1993.07a
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The use of preformed polymers and their cross-linking have been attempted in order to improve the intrinsic fragility of monolayers and Langmuir-Blodgett (LB) films and to make their technological applications possible. It has shown that an imidization followed a polyion-complexation can stabilize the LB films against heat and solvents. And, when the polymer structure was property designed, concurrent removal of the alkyl tails together with imide formation could be accomplished. In this paper, we present a characteristic monolayer behavior of polymer with pendent polyethers and carboxyls, it's polyion-complexed LB film with subphase polymer PAA, and a possible skeletonization of the LB film by thermal imidization. Also, deposition status of LB films are evaluated by using QCM.
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In this paper, we proposed a new method which does not need no load test for the characteristics analysis of linear induction motor. A new equivalent circuit of LIM is chosen and a method of determining its constants from results of the lock test is discussed. The calculated results were satisfactorily agreed with experimental results and conventional method.
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This paper decribed the development of Thermal Imaging Oservation System(TIOS) using the serial-parallel scan method. The detectors scan five lines at a time. These are put into serial order by electronic scan converter. Digital memory and high speed multiplexer are used for the serial conversion instead of charge coupled devices. As a result, thermal imaging system be presented with exellent performance which MRTD value is less than
$0.5^{\circ}K$ at 7.5 cycles/mm. -
The correlation between electrical conduction and dielectric relaxation properties of copper ion conducting glasses is discussed. The glasses were prepared in the system
$CuI-Cu_2S-Cu_2O-MoO_3$ using rapid quenching technique. These glasses have high ionic conductivities at room temperature in the range of$10^{\circ}$ [S/m], and the conductivities increase with increasing CuI content. The activation energies for conduction are 0.26 - 0.57 eV. The dielectric relaxation times are 1 - 10uS, and the activation energy for ion jumping are 0.18 - 0.41eV. It is shown that the tendency of conduction properties depending on composition of the glass is similar those of dilectric relaxation. -
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In this study PLZT was selected which has the excellent quadratic electro-optic property and slim-loop. It was fabricated by the methods of vacuum hot-pressing and sintering. The electrode of color filter was evaporated using the interdigital type masks. Through XRD have we investigated the molecular structure composition formular. Hysteresis and transmission characteristics were measured, The transmission of RGB was envestigated. We are going to study the correlation of coercive field and the nontransmited field.
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The dielectric properties of pressboard depend on the chemical and fine structures as well as on the macroscopic structure of pressboard. The investigate on the dielectric characteristics of pressboard therefore, provides an important approach to an understanding of the correlation between the characteristics and the structure of pressboard. The purpose of this research is to investigate the dielectric properties of pressboard.
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A technique computing short-term load foadcasting is essential for monitoring and controlling power system operation. This paper shows the use of general exponential smoothing to develop an adaptive forecasting system based on observed value of hourly demand. Forecasts of hourly load with lead times of one to twenty-four hours are computed at hourly intervals throughout the week. Standard error for lead times of one to twenty-four hour range from three to four percent average load. Studies are planned to investigate the use of weather influence to increase forecast accuracy.
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This paper presents a new optimal VAR planning algorithm considering voltage stability margin. The characteristic of this method is to make it possible to formulate VAR planning for the dual purpose of maintaining voltage profiles within specified limits, and increasing the voltage stability margin of anticipated operating conditions with respect to voltage collapse. The IEEE-30 bus system is used to demonstrate the capability of the proposed algorithm.
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This study considers the economic aspect of the distribution automation system, which is the decision-making criteria of the electric utilities for the investment. The feeder automation candidate region is divided into two types of the urban and the rural. The total investment cost of the feeder automation for each type is estimated. The annual cost, is also estimated, by finding the fixed charge rate. To compare the annual cost and the economic effect cost, for the investment decision-making, the costs are quantitatively estimated on the following effects : the manpower replacement, the outage cost saving, the main transformer utilization improvement, the feeder utilization improvement, and the line loss reduction.
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This paper presents the development of interactive graphical software for the educational purpose of power flow(PF) calculation. The developed software is specially designated to give a beginner the interest on PF problem as well as to increase the understanding of it with ease. the software developed in this paper is basically composed of the pull-down menu driver, in which various functions, such as Program Master, Data File Management, Case Study Option, PF Run and View Output, are prepared to handle the software easily and thus to be familiar with power flow calculation. A special design is also considered for interactive operation of the software, wi th which user can interrupt the computation process of PF to control the convergency of PF algorithm, With this function begineer can acquire the understanding of convergency characteristics and numerical sensitivity of PF algorithm as well as basic concept of its computation logic. Futhermore, various graphic illustrations is also provided to review and compare the computation results on monitor.
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As for the organization of actual test facilities, we carried out the conceptual design for the actual test facilities related to PAFC simulater, PCS, distribution feeder, dummy load, measurement system and fault generation equipment.
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Load Management, is originated from efficiency improvement of energy use, or energy conservaion. Traditionally, electric utilities have constructed new power plants to meet the steadily increasing electricity demand. Power development planning, however, is becoming more difficult in the countries like Korea, Japan, and the United States, and increasing concerns about global environmental problems necessitate changes from existing supply-side options based on fossil-fuel to environmentally agreeable supply strategies. This paper discusses the demand side management strategy with emphasis on the concept, implementation scheme, and current practices employed in utilities.
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One of the most important functions in the distribution automation is the service restoration. This paper proposes the new method which considers not only constraints of voltage, line current and bank capacity but also the operating characteristics of protective devices such as OCR and reclosers.
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This paper proposes a design of the tracking controller using artificial neural network and the compare the result with a result of optimal controller. In practical use, conventional Optimal controller has some limits. First, optimal controller can be designed only for linear system. Second, for many systems state observation is difficult or sometimes impossible. But the controller using artificial neural network does not need mathmatical model of the system including state observation, so it can be used for both linear and nonlinear system with no additional cost for nonlinearity. Designed multi layer neural network controller is composed of two parts, feedforward controller gives a steady state input & feedback controller gives transient input via minimizing the quadratic cost function. From the comparison of the results of the simulation of linear & nonlinear plant, the plant controlled by using neural network controller shows the trajectory similar to that of the plant controlled by an optimal controller.
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A systematic procedure for determining the elements of system state matrix is suggested. The interrelation of submatrices of the system matrix is investigated. Each element or each block can be represented in algebraic form. These results can be applied in the eigenvalue sensitivity analysis with respect to the changes in controller parameters.
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This study suggests a dynamic braking control algorithm in order to improve the transient stability of a multimachine power system. Dynamic braking control has been known as an effective method by which transient stability of power systems could be improved. Under the context, the study suggests a modified MRVM which possibly handles more rapid on-line computation through the improvement of the conventional MRVM(Model Referenced Velocity Matching). In order to resolve the phenomenon of stability recovery hinderance due to the prolonged dynamic braking control under the stable equilibrium state and chattering problem, the study also composes an algorithm in such a way that dynamic braking control could be prohibited by setting-up absolute stability region, Lastly, a comparison with the results derived from the application of the conventional control technique to the model power system is made in order to prove the superiority of the suggested control technique.
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This parer propose an adaptive methodlogy for setting of the underfrequency relays that is based on the initial rate of change of the frequency at the relay. During severe emergencies which result in insufficient power generation to meet load, an automatic load shedding program throughout the affected area can prevent total collapse. To avoid this kind of insufficient power generation, load shedding relays are often applied throughput the system to provide a means of helping balance the load to the remaining generation. Comparing, it has been found that the use of the proposed method for the amount and the timing of load shed more efficiently than the conventional method.
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This paper presents an efficient method to calculate voltage collapse point and to improve static voltage stability. To evaluate static voltage stability in power systems. it is necessary to get critical loading points. For this purpose, we use linear programming to calculate efficiently voltage collapse point. And if index value becomes larger than given threshold value, vol tags stability is improved by compensation of reactive power at selected bus. This algorithm is verified by simulation on the sample system.
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The purpose of the facility investment planning for bulk power system is to appropriately configure the power system network to supply the load, which has the supply capability satisfying the probabilistically changing load on the desired reliability level. In order to achieve this purpose, this paper represents the reliability evaluation of the KEPCO's real system with using the MEXICO model, and builds the data base of the power system operation in order to effectively handle the computer model.
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This paper presents an expert system that sheds loads considering priority in the localized SCADA power systems during an emergency states. The proposed algorithm uses neural networks to detect local load shedding location and heuristic rules to determine load shedding amounts. The proposed expert system is demonatrated at one of the model system which incorporates two localized SCADA power system. It is operated under workstation.
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In recent years, it is widely being issued to consider the Non-Utility Generation (NUG) in the public electric utility sector. The Non-Utility Generation can be divided into two major parts, i. e., dispersed generation and privatization. In the participation of the NUGs in the public sector, the economy of scale and publiciy of the NUGs should be considered. In this paper, we with give the present status of Non-Utility Generation and. problems caused by the dispersed generation and privatization. Also, the analysis of the problems of NUGs and future policies of the electric utility will be discussed.
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This paper describes an efficient method of computing any desired number of the most unstable eigenvalues and eigenvectors of a large scale multi-machine power system. Approximate eigenvalues obtained by Hessenberg process are refined using Rayleigh quotient iteration with cubic convergence property. If further eigenvalues and eigenvectors are needed, the procedure described above are repeated with deflation. The proposed algorithm can cover all the model types of synchronous machines, exciters, speed governing system and PSS defined in AESOPS. The proposed algorithm applied to New England test system with 10 machines and 39 buses produced the results same with AESOPS in faster computation time. Also eigenvectors computed in Rayleigh quotient iteration makes it possible to make eigen-analysis for improving unstable modes.
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We have proposed a new technology compensating reactance component of line and load. Because capacity of SC is static, it is not appropriate to varing reactance and causes SSR problems. TCSC is introduced for the flecxible control of reactance of SC. If SC voltage is varied when the capacitor current is constant, it can be considered that capacity of SC was varied. SO capacity of SC can be controlled by controlling the voltage of SC. Control reference voltage of SC can be obtained from the condition that sum of reactive powers in all parts is zero.
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The load forecasting has been essential in planning and operation of power systems. The load composition rata is also needed to analyze power-systems - load flow calculation and system stability. This paper proposes the monthly peak load forecasting methods for load groups in residential class using load composition rate and electric consumption characteristics. The proposed methods were applied to a real-scale power system and the effectiveness was turned out.
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This paper contains the various effect of distribution feeder sectionalizing by distribution automation. The effect by automatic sectionalizing switch and the effect by manual switch are analyzed and shown according to the radial feeder and the loop feeder respectively. Based on the reliability analysis, the reference for the feeder division and sectionalization is recommended. Also, the necessary number of manual switch where the automatic switch is installed is recommended through the reliability analysis.
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Stability analysis is an essential work in the operation and planning of power system. There are two categories, direct method and indirect method, and indirect method calculates the trajectories of states by numerical methods. Popular method using explicit integration has relatively low accuracy, so a more accurate method is requested. By the consideration of bus voltage variation, Runge-Kutta 4th order method can be made more accurate, but this scheme need much computation time. Through three recipes, computational cost of proposed method can be reduced. So the proposed method has improved accuracy and slight rise in cost. the method was tested on the IEEE 14 bus system.
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This paper proposes the enhanced rules for setting and coordination of the relays in the distance relaying. The developed new rules to diagnose the coordination based on the system information are expected to be very helpful in the system expansion planning stage. An expert system to adopt those rules have been developed using the hybrid AI tool, NEXPERT-OBJECT.
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In accordance with increase of electrical power demanded, more efficient supervisory control of distribution system is required. This study contains development of MMI(man-machine-interface) system with GUI(graphic-user-interface), for the automatic power distribution system. The main function of MMI system are to edit network of power distribution, to view network, to warnning a breakdown and to management of data base for network. The GUI function of MMI system enables more efficient management of power distribution system.
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This paper presents an approach to feeder reconfiguration in order to achieve an efficient operation of distribution systems utilizing knowledge base. The optimal feeder reconfiguration in this study eliminates various abnormal states which will create feeder overloads and feeder constraint problems. and will also accomplish minimum power loss of the distribution systems under normal operating condition by means of branch exchanges to change the status of sectionalizing switches with experiences of the experts. For an effective implementation of feeder reconfiguration, a best-first tree searching strategy based on heuristics is employed to evaluate the various alternatives of load transfer. The heuristic exchange of branches results in reduction of the search space as a means of implementing the best-first searching strategy.
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The objective of this study is to solve the operation scheduling problem of plural battery energy storage systems (BESS), and to find useful intonation from its result. Unlike conventional energy storage system, BESS has on hardware characteristics such as high efficiency, fast-acting response and operational loss. Considering rate constraints of thermal unit power as well as hardware characteristics of BESS, the operation scheduling has an intricated problem. In order to solve this optimization problem, we use successive approximations dynamic programming. In two types of operation, the proposed algorithm is applied to test system. one is daily optimal operation, the other weekly optimal operation.
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This paper gives derivations of voltage collapse conditions by using the Lyapunov function, which yields the exactly same results with the sensitivity analysis approach. On the other hand, the voltage collapse phenomenon is interpreted in the physical sense, and causes of the static voltage unstability and the dynamic voltage unstability are analyzed with the use of proposed Lyapunov function. In addition a new method is developed to calculate the power capacity limit of transmission lines with respect to voltage stability. This paper shows that it is able to analyze the voltage collapse with the Lyapunov direct method in the simple 2-bus system and proposes that the method works well by observing the variation of Lyapunov function as the load is increased in the system.
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This paper proposed a regulation technique of scale factors on fuzzy controller for power system stabilization. These scale factors arc regulated by a given exponential function with performance index variables. Simulation results show that the proposed fuzzy control technique are more powerful than conventional ones in faces of usefulness and robustness.
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This paper presents a partitioning technique for equivalent models to large scale power system. The proposed partitioning technique is utilized by using a heuristic approach based on distributed array processor and the coherent groupings of generator buses. In this paper the reduced Ward-PV method considering the characteristics of buses is used to equivalent models of external system. The technique is demonstrated on New England system with 39 buses, 46 lines and 10 generators.
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This paper presents a new method for solving unit commitment problem including hydro and pumped storage hydro units in a large scale power system. The proposed method makes it possible to get variable power of hydro and pumped storage hydro units and results in the better unit commitment with good convergency. Moreover this paper proposes an unit commitment algorithm to consider variable power of these units effectively by Lagrangian Relaxation method. By applying the proposed method to the test system, it is verified the usefulness of this method.
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This paper presents the developing a new algorithm for detecting the Back fed Earth Fault in three wire-unigrounded distribution system by zero sequence admittance. So called "Backfed Earth Fault" of the electric power distribution line refers to a class of earth faults that the load-side line only is grounded, following after the distribution line broken into two parts, the source-side and the load-side. Because its mechanism differs from that of other earth faults, it is therefore, required to examine. This paper deals with the detailed software of the digital protective relay for Backfed earth fault. In order to prove that the proposed schemes is good, we performed off-line simulation using data from EMTP and ETSA(Electrcity Trust Of South Austrilia). It is shown that the suggested algorithm is never mal operated.
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This paper presents the new algorithm for fault analysis and the fault analysis package for executing this algorithm. This algorithm obtains requisite term for fault analysis by the two-port network technique. Therefore, the fault calculation time is minimized because
${Y_{BUS}}^{-1}$ calculation time is removed. And, the graphic user environment for fault analysis is implemented in mouse-oriented user interface with window and pull-down menu. Therefore, this package can be a useful tool for fault analysis. -
In this paper, we introduce 'Expert System(ES)' for Fault Diagnosis(FD) in unmanned-Substation(S/S). In contrast with the co nventional ES, this ES has the following characteristics. First, this ES performs the function that judges the right or false operation of Relays(Ry's) and Circuit Breakers(CB's) in S/S. Then, with this information of the above judgments and the operating times of Ry's and CB's, the candidates of the feasible fault areas are generated. Several examples are presented to show the validity of this system.
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In the power system state estimation, the J(x)-index test and normalized residuals
$r_N$ have been used to detect the presence of bad measurements and identify their location. But, these methods require the complete re-estimation of system states whenever bad data is identified. This paper presents back-propagation neural network model using autoregressive filter for identification of bad measurements. The performances of neural network method are compared with those of conventional methods and simulation results show the good performance in the bad data identification based on the neural network under sample power system. -
This paper presents a novel and efficient method to calculate the critical point of voltage collapse. Conjugate gradient and modified Newton-Raphson methods are employed to calculate two pairs of multiple load flow solutions for two operating conditions, i.e., both +mode and -mode voltages for two loading conditions respectively. Then these four voltage magnitude-load data sets of the bus which is most susceptible to voltage collapse, are fitted to third order polynomial using Lagrangian interpolation in order to represent approximate nose curve (P-V curve). This nose curve locates first estimate of the critical point of voltage collapse. The procedure described above is repeated near the critical point and the new estimate will be very close to the critical point. The proposed method is tested for the eleven bus Klos-Kerner system, with good accuracy and fast computation time.
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This paper details methods used to verify the adquacy of a dc traction power supply for design in Seoul matropolitain subway Line-6 system. Examples of the approach are given for a major subway presently under construction. The performance of trains operating at maximum system design capacity is modelled using a train simulation program. Using a dc network analyser program, the maximum train operating timetable, and a model of the ac and dc electrical suppy system, the electrical performance of the entire system can be modelled over a 24-hour period. The results of this analysis are used to determime: train voltage at a level sufficient to ensure train schedules: adequacy of traction transformers, rectifier, and switchgear ratings; sizes of the overhead contact systern conductors, and ac and de feeder cables: and power and energy demands at the utility company's supply points for inital and final timetable operations.
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Station Blackout(SBO) event means the complete loss of alternating current(AC) electrical power to the essential & nonessential switchgear buses in a nuclear power plants. Since many safety systems in nuclear power plants depend upon alternative current power, the SBO event could be an important contributor to damage of reactor core. Therefore, the SBO events have been considered as a very important safety issues in a nuclear power plants. In this paper, as evaluating the design characteristics of offsite & emergency power systems, an acceptable minimum SBO duration is calculated. And it is presented that the design method for alternative AC(AAC) sources to cope with the SBO events.
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The long-term electricity resource planning of electric utility has undergone significant change during the past decade. The current resource planning can be considered as multi-objective decision making procedure under the various uncertainties such as demand growth, construction cost, fuel price, environmental regulation, plant site, financial adequacy, new technology advent and so on. This paper presents a standardized electricity resource planning scheme using the strategic planning concept. EGEAS computer model was fully applied to indentify feasible alternative plans and simulate various attribute values corresponding each alternative plan and future. As a case study, a hypothetical long-ten capacity expansion planning problem is analyzed.
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Load models for the analysis and simulation of power system are often introduced when the more accurate result is required. This work presents a single expressed load model as T-equivalent circuit of induction motor, for the composite characteristics of various loads. The parameters of the proposed load model are identified based on the system identification method as Recursive Least Square identification method. Case study results show the accuracy of proposed load model, and compared with some field measurements.
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Protective Relay in power system play a prominent part in minimizing power delivery interruptions and help to get a fast and secure restoration when a failure occurs. In order to meet the higher functional requirements in power system, the performance tests on response characteristic of protective relay is essential to ensure reliability. The purpose of this study is as follows: In order to evaluate performance of protective relay, it is intended to develop performance of digital protective relay simulator which is composed of digital protective relay part, behaviour analysis part, waveform generation part and simulation program to simulate pour system in detail.
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This paper presents several techniques of power spectrum estimation for high impedance fault detection. High impedance faults are those faults with current too low to be reliably cleared by conventional overcurrent protection. So power spectrum estimation is required. AR and MA techniques require optimal order for good performance of power spectrum estimation because these techniques are unstable for order selection. ARMA and Extended techniches are stable for order selection and have very sharp response. So ARMA and Extended Prony techniques are suitable for our purpose.
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A new approach using fuzzy dynamic programming is proposed for the flexible long-term generation mix under uncertain circumstances. A characteristic feature of the presented approach is that not only fuzziness in fuel and construction cost. load growth and reliability but also many constraints of generation mix can easily be taken into account by using fuzzy dynamic programming. The method can accommodate arbitrary shape of membership function as well as the operation of pump-generator. And so more realistic solution can be obtained. The effectiveness of the proposed approach is demonstrated by the best generation mix problem of KEPCO-system which contains nuclear, coal, LNG, oil and pump-generator hydro plant in multi-years.
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This paper describes an parallell computing algorithm in Gauss elimination of Jacobian matrix to large-scale power system. The structure of Jacobian matrix becomes different according to ordering method of buses. In sequential computation buses are ordered to minimize the number of fill-in in the triangulation of the Jacobian matrix. The proposed method using ND(nested dissection) ordering develops the parallelism in the Gauss elimination to have balance of computing load among processes and each processor uses the sequential computation method to preserve the sparsity of matrix.
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This paper deals with AVR(Automatic Voltage Regulator) control1or design of synchronous generator adapting AC indirect excitation system. The simulation results are presented in frequency and tine domain for two plants(A and B). Try and error method for compensator design is used.
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This paper deals with a methodology of the dynamic voltage stability analysis. The several physical power system constraints e.q upper and lower lomit of SVC and OLTC are considered. The proposed equivalent load model is the combination induction motor and impedance load. The variation of System voltages and equivalent induction motor slips for actual power systems are simulated and plotted in this paper.
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Laying up homogeneous power cable in the earth. we sure that one of the most effectest fact is the rising of thermal resistivity. Today, system designing of in and outdoor project, calculating current carrying capacity totally depend on standard of JCS-168D and IEC-287 to applicate. Specially, the formula of calculating soil thermal resistivity is what is based on KENELLY,s is usually used. In this report, Let's study the formula of soil thermal resistivity which was born in the idea of KENELLY.
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Best generation mix belongs to a multi attribute decision making, because we should consider many uncertain factors and choose the best one of the alternatives. Sugeno's fuzzy integral has been used as the solution of multi attribute decision making, but the exact value of the coefficient
$\lambda$ hat not known yet which is needed to calculate fuzzy measure. This paper proposes the new method to calculate fuzzy measure without fixing the value of$\lambda$ . The proposed method considers$\lambda$ as a probability distribution function and calculated expectation of fuzzy measure. The method is applied to the test system and the validity of the method is verified. -
A distance protection algorithm for detecting faults at power transmission lines is presented in this paper. The algorithm is based on the differential equation related to the voltage and the current at an equivalent circuit of a transmission line which is composed of the lumped resistance and inductance. The presented integration method has high performance at though the fault voltage and the current are heavily distorted with the DC offset and harmonics which occurred at transient states after faults.
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The SCADA (Supervisory Control And Data Acquisition) system made by HARRIS corporation of U.S.A for special propose industrial computer is currently used for Power control in KEPCO (Korea Electric Power corporation). But it's I/O expression is composed or only alpha-numeric and semi-graphic characters. So operators have had some troubles and difficulties. We have studied and implemented Hanguel (Korean Character) in this system to solve these difficulties. In this paper we'll discuss the method and technics of Hanguel Implementation on SCADA system, and trendency of Hanguel implementation will be added.
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This paper reports a status of KLDN(Korean Lightning Detection Network) SYSTEM in Korea, which was constructed by KMA(Korean Meteorological Administration) & KERI(Korean Electrotechnology Research Institute). At first, system configuration was introduced, and then lightning location data between August/1992 & April/1993, which was obtained in KLDN SYSTEM, was analyzed statistically. Finally, we show the future research planning in relation with this KLDN SYSTEM.
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A systematic procedure for the elements of system matrix in multimachine systems with loads is suggested for the small-signal stability studies. Synchronous machines are represented by either a two-axis model or classical model. The interrelationship of submatrices of system matrix is investigated. Once elements of one submatrix are determined, they can be used to calculate the elements of the other submatrix. It is illustrated for three machine and nine bus multimachine systems with constant impedance loads, constant MVA load, constant current and power factors.
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This paper presents an efficient method for determining the economic dispatch of thermal generator using an alternative Jacobian matrix considering system constraints. The transmission loss is approximately expressed as a funtion of generating powers and the generalized generation factor. From this expression, the Jacobian matrix is formulated and solved by the Newton Raphson Method. In this method, the economic dispatch problem is solved rapidly without calculating the penalty factor. The proposed method has fast convergency characteristic and good accuracy. The feasibility of this method is demonstrated by means of examples.
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This raper describes a nev program designed as a part of the integrated software package for distribution system planning and operation. The program accesses electrical map databases which include both electrical and geographical information. Data retrieval, load flow analyses, and reconfiguration studies can be easily performed in highly interactive environment on graphics and pull down menus, case study results demonstrate the practical usefulness of the program at the real systems.
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In this paper a numerical model of the industrial cogeneration system which have a thermal storage tank is proposed for the short-term operation strategy. Short-term operation costs of towing cycle and bottoming cycle are calculated by using the proposed model of a thermal storage tank. Simulation results of four cases are compared and analyzed each other. By these simulations which are similar to real operation circumstances, the validity of the proposed model is verified.
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Appropriate control of real and reactive power flowing in and out from system can lead to considerable benefits : network stabilization, load leveling, voltage regulation etc. This paper presents how to control real and reactive power flow between an flywheel energy storage system and a power three phase network. The system compensating real and reactive power consists of control system and cycloconverter operating in the four quadrant modes.
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Distribution planning requires comprehensive knowledge about not only distribution but also transmission/subtransmission system expansion plan. At the same time, distribution planning is very time consuming and a series of routine job which involves a lot of experience and efforts of planning engineers. Since the quality of distribution planning depends upon the ability of planning engineers, the economy of investment should be taken into consideration. The object of this study is to establish a computerized distribution planning system which helps distribution engineers finding a new system expansion plan. It provides the engineers with at optimal system expansion plan which satisfies the condition of both reliability and economy.
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In this paper, we proposed a design method of self-learning fuzzy logic controller using fuzzy neural network. The parameters of membership function in premise are modified by descent method and also consequent parameters by learning mechanism of animal conditioning theory. The proposed method is applied to pole balancing system in order to confirm the feasibility.
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This paper presents a new identification method which utilizes fuzzy inference in parameter identification. The proposed system has an additional control loop where a real plant is replaced by a plant model. The control system to be designed is to satisfy the following specifications: 1) It has zero steady-state error. 2) It has adequate damping characteristics. 3) 1),2) satisfied, it has a shortest rise-time. Fuzzy rules describe the relationship between comparison results of the features and magnitude of modification in the model parameter values. This method is effective in auto-tuning because the response of the closed loop is verified. The proposed method is tested in simulation for several plants with first- order lags and dead-times. The results show that the proposed method is effective in practical use.
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This paper deals with a self-tuning fuzzy controller. The fuzzy controller is constructed with linguistic rules which consist of the fuzzy variables and fuzzy sets. Each of fuzzy sets is characterized by a membership function. The tuning fussy controller has paramemters to effect control output. In this paper we propose tuning method for the scaling factor. Computer simulations carried out on a second-order process will show how the present tuning approach improves the transient and steady-state characteristics of the overall system.
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The Hopfield model is defined as an adaptive dynamic system. In this paper we propose a modified neural network which is capable of solving linear programming problems and a set of linear equations. The model is directly implemented from the given system, and solves the problem without calculating the inverse of the matrices. We get the better stability results by the addition of scaling property and by using the nonlinearities in the linear programming neural networks.
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Multi-layered neural networks offer an exciting alternative for modelling complex non-liner systems. This paper investigates the identification of continuous time nonliner system using neural networks with a single hidden layer. The digital low - pass filter are introduced to avoid direct approximation of system derivatives from sampled data. Using a pre-designed digital low pass filter, an approximated discrete-time estimation model is constructed easily. A continuous approximation liner model is first estimated from sampled input-out signals. Then the modeling error due to the nonlinearity is decreased by a compensator using neural network. Simulation results are given to demonstrate the effective of the proposed method.
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Recently, the development of novel control methodology enables us to improve the performance of AC-machine drives by using pulse width modulation (PWM) technique. Usually, the dynamic characteristic of induction motor (IM) has been represented by the 5-th order nonlinear differential equation. This dynamics, however, can be reduced to 3-rd order dynamics by applying direct control of IM input current. This methodology concludes that it is much easier to control IM by means of the field-oriented methods employing the current controller. Therefore a precise current control is crucial to achieve a high control performance both in dynamic and steady state operations. This paper presents an adaptive fuzzy current controller with artificial neural network (ANN) for field-oriented controlled IM. This new control structure is able to adaptively minimize a current ripple while maintaining constant switching frequency. Especially the proposed controller employs neuro-computing philosophy as well as adaptive learning pattern recognizing principles with respect to variations of the system parameters. The proposed approach is applied to the IM drive system, and its performance is tested through various simulations. Simulation results show that the proposed system, compared among several known classical methods, has a superb performance.
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This paper deals with the design of an adaptive controller using neural network. We present RBFMLP Neural Network which consists of serial-connected two networks - Radial Basis Function Network and Multi Layer Perceptron, and then design a controller based on proposed networks with the adaptive control system structure, The plant and parameters of the controller are identified by the neural networks. We use the dynamic backpropagation algorithm for the learning of networks. Simulations represent the superiorities of the proposed network and the controller.
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Semiconductor devices generate harmonics which induced bad effects against power distribution systems. To surpress harmonics, the filter design and the identification of harmonic load sources are needed. In this paper, artificial neural networks are used to identify the nonlinear relationship between harmonic loads and harmonic currents that vary at times. To find the best adequate network for solving this identification problem, we compared with recognition rates of neural networks by changing hidden layer neuron number.
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In this paper, back-propagation neural network is used to implement a controller for electric furnace. Although the dynamics of furnace is nonlinear and time-delayed and depends on the environment, the time constant is relatively large so that manual control based on human expert can have good performance. The input-output data of the manual controller are collooted and used as training data for neurocontroller. From simulation. we find that the neurocontroller has better performances than the conventional controller.
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In this paper, a class of neural-network controllers with two inputs of error and error change, is applied to the position control of D.C. servo system. The proposed controller is learned by error back-propagating error information to compensate the weighting value using its previous derivatives and to decrease exponentially a series of self learning coefficients. Through the simulations and implementations, the effectiveness and superiority to the conventional fuzzy controller is proved.
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In this paper, Fuzzy-Neural Network Control system that has the characteristic of fuzzy control to be controlled easily end the good characteristic of a artificial neural network to control the plant due to its learning is presented. A fuzzy rule to be applied is selected automatically by the allocated neurons. The neurons correspond to Fuzzy rules which ere created by a expert. To adaptivity, the more precise modeling is implemented by error beck-propagation learning of adjusting the link-weight of fuzzy membership function in Fuzzy-Neural Network. The more classified fuzzy rule is used to include the property of Dual Mode Method. To test the effectiveness of the algorithm presented above, the simulation for position end velocity of DC servo motor is implemented.
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In this paper, we assume that the dynamics of DC motor and nonlinear load are unknown. We train the inverse dynamic model of DC motor and nonlinear load using the neural network and construct speed control system based on the traind dynamic model and current control mode. Speed prediction scheme using neural network is also proposed the alleviate the time delay effect caused by the computation time of neural network. Simulation results show good performances of the control system. Finally, hardware configuration of the control system is outlined.
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This paper proposes an automatic tuning fuzzy controller for frequency control of a hydro power plant (HPP). The proposed automatic tuning fuzzy controller consists of fuzzy control part and scaling factor calculation part. Scaling factor tuning is based on the concept of conventional tuning rules for the PI controller. The proposed controller was evaluated by simulation. Good results have been obtained for the 5kW model HHP.
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This paper presents a new method to implement Hebbian learning method on artificial neural network. In hebbian learning algorithm, complexity in terms of multiplications is high. To save the chip area, we consider a new learning circuit. By calculating similarity, or correlation between
$X_i$ and$O_i$ , large portion of circuits commonly used in conventional neural networks is not necessary for this new hebbian learning circuit named COR. The output signals of COR is applied to weight storage capacitors for direct control the voltages of the capacitors. The weighted sum,${\Sigma}W_{ij}O_j$ , is realized by multipliers, whose output currents are summed up in one line which goes to learning circuit or output circuit. The drain current of the multiplier can produce positive or negative synaptic weights. The pass transistor selects eight learning mode or recall mode. The layout of an learnable six-neuron fully connected Hopfield neural network is designed, and is simulated using PSPICE. The network memorizes, and retrieves the patterns correctly under the existence of minor noises. -
This paper presents an on-line monitoring and control system designed for the automation of a Concrete plant. The system is based on the combined structure composed of a general purpose PLC (Plogrammable Logic Controller) and a personal computer. Simulation results are ahem to illustrate the system operation. Preconstructed rules are applied to the plant data for the diagnosis of the weighing process in the simulation.
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This paper proposes an adaptive generalized predictive control with feedforward algorithm for steam generator level control in nuclear power plant. The proposed algorithm is shown that the parameters of N-step ahead predictors can be obtained using the parameters of one-step ahead predictor which is derived from plant model with feedforward. Using this property the proposed scheme is an adaptive algorithm which consists of GPC method and the recursive least squares algorithm for identifying the parameters of one-step ahead predictor. Also, computer simulations are performed to evaluate the performance of proposed algorithm using a mathematical model of PWR steam generator Simulation results show good performances for load variation. And the proposed algorithm shows better responses than PI controller does.
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A control for Steam Generator (S/C) level is very difficult by automatic control mode but also manual control node during plant start up and/or low power level operation with the analog control system because of a non-nominal process responce. The goal of this study is to improve and computerize and applicate for KO-RI #1 Steam Generator level control system.
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Implementation of DSP Controller for Levitation of EMS System using Nonlinear Feedback LinearizationThe implementation of Nonlinear Feedback Linearization control for Electro-Magnetic Suspension system is presented. The controller using TMS320C31 DSP chip was proposed and the experiments were performed Control law for EMS system using feedback linearization is derived and implemented in the DSP. Some tests were constructed far experimental comparison between feedback linearization and classical state feedback The experimental results demonstrate that the feedback linearization controller shows bettor performance than that of the classical state feedback controller and it is robust with respect to disturbance and parameter variation, though some steady-state errors appear.
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One maglev vehicle is composed of 6 or 8 modules. Each module is composed of 4 staggered magnets attached to an aluminum bogie. In the view point of levitation control except propulsion-by LIM. 5 is the maximum degree of freedom to be controlled. But rolling control of the vhhicle depends on the bogie structure. We describe just anti-roll type bogie structure and 4 degree of freedom control is sufficient for levitation quality improvement. Multivariable pole-placement concept is used for controller design. Control experiment is performed on a specially designed test module as well as actual bogie system.
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When the noise is mainly caused by a detector and is statistically independent of the incident radiation, the multiplexing inherent in the Hadamard transform (HT) spectrometer can provide an improved spectrum-estimate. A spectrum-estimate can be further improved when any nonidealities in the system are compensated. In this research, three spectrum-estimation methods for an HT spectrometer having a nonideal mask are discussed in terms of computational efficiency, statistical bias, the sources of error, and the mean-square error associated with a given estimate. In addition, the results obtained from computer simulations are used to verify the theoretical foundation of each method.
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A new method of EEG spindle waveform detection i s presented. The method combines the signal conditioning in the time-domin and the analysis of local spectrum in the frequency-domain. Fast computation methods, utilizing some effective approximations, are also suggested for the desist and implementation of the filter as well as for the computation of the local spectrum. The presented approach is especially useful for the real-time implementation of the waveform detection system under a general purpose microcomputer environment. The overall detection system is implemented and tested on-line with the total 24 hour data of selected four subjects. The result show the average agreement of 86.7% with the visually inspected result.
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Software and hardware for cochlear implant system have been developed to create a speech signal processing system which, in real-time, extracts model parameter including formants, pitch, amplitude information. The system is based on the Texas Instruments TMS320 family. In hardware, computer interface has been desisted and implemented that allows presentation of biphasic pulse stimuli to patients with the hearing handicapped. The host computer sends a stream of bytes to the parallel port. Upon receipt of the data the interface generates the appropriate burst sequence that is delivered to the patient's external transmitter coil. The coded information is interpreted by the Nucleus-22 internal receiver that delivers the pulse to the specified electrodes at the specified amplitude and pulse width.
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Recently semiconductor technology is widely used in biotechnology fields and one of the represetatives is electric cell-fusion-device. In this paper. some basic researches required in the development of this fusion system was performed and they are as follows: 1) preparation of protoplast and selection of the fittest plant cell, 2) development of high frequency AC power supply for cell-alignment by using class-E resonant circuit. As a result, cabbage cell is selected and pearl-chain, which shows cell-alignment. can be observed by the applied AC field.
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In this paper, analysis of the noise induced by rotating machines and the mode analysis of a 3-dimensional enclosure are presented. Adaptive active noise control algorithms for the multi-channel case are proposed. Computer simulations were done to show usefulness of the designed algorithm in a 3-dimensional enclosure case.
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Most control system design problems involve finding state feedback gain for good response by the pole or characteristic polynomial assignment. In this paper, the characteristic polynomial assignment using PID controller for discrete 2-dimensional system descrived by the Fornasini-Marchesini's 2nd model (F-MM II) is considered. This method it not only available to F-MM II but also to Rosser's model.
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In this paper, a new design procedure is proposed for constructing the observer for linear discrete-time systems with unknown inputs. An existence condition for the suggested observer is also presented. The observer design procedure does not use any transformation technique, augmentation technique and has a clear physical meaning, so it is easy to understand and to design the observer. It directly estimates the unknown inputs from that outputs only, so it is different from other pre-works in which the reconstruction of the unknown inputs arc performed with the additional output derivatives.
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Some well known order reduction methods are briefly described and a nev order reduction technique is introduced. A comparison of the various classes of order reduction approaches are indicated. Furthermore, the question is raised how order reduction should be executed with respect to controller design. Finally, by means of an example, results of the discussed approaches are compared.
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Walsh function and transform are important analytical tools for control theory and signal processing and have wide applications in those fields, especially in the field of digital communications. Therefore there is a need for a Walsh function generator in order to realize certain applications. And a number of different desists are known. But desist and implementation of such a generator through hardware logic nay give rise to orthogonality error. To develop Walsh function generator which gets rid of orthogonality error, this paper presents a microprocessor based design and implementation method.
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Digital redesign techniques are to derive a digital controller fred the existing continuous controller and its plant so that the performance of the digitally controlled system is matched as closely as possible to that of the original continuous system at the sampling instants. Recently a new digital redesign technique, was developed to use the generalized sampled-data hold function(GSHF) based on the the grammian matrix. With this new technique the digitally redesigned system showed several good features compared with any existing technique in terms of the state match at the sampling instants, the large sampling period, and the transient reponses. This paper concerns a further improvement of the new digital redesign technique by employing the discrete grammian matrix instead of the continuous grammian matrix in defining GSHF. With this modification, it was observed by simulation that the transient response of the modified digital system shows far better performance than the digital system based on the continuous grammian matrix.
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We present the discrete event systems modeled by finite state machines in this paper using the boolean matrices and vectors. We propose a supervisor synthesis method for such boolean discrete-event systems. The proposed supervisor synthesis algorithm is practically implementable, since the size of the state vector in the product system does not increase exponentially with the number of components.
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This paper presents the control of input/output automata. The input/output automata provides an appropriate model for discrete event systems consisting of concurrently-operating components. Ramadge and Wonham's supervisor controller can be transformed into the controllter of input/output automata. Using input/output automata, the modelling can be more realistic and concurrent discrete event systems can be controlled easily.
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In order to estimation the optimum PID parameter of the turbine speed controller, the response cure of the object plant was compared with the reference pattern and then the magnitude peak value error and peak time error was calculated. With the calculated errors as input into the Fuzzy inference Method was introduced to propose the tuning method for each parameter. And the computer simulation was performed with the above Fuzzy inference method in which the Chunju hydro power plant turbine governor system was used as a model. This Study also aims to develop the exclusive tuner for govenor using industrial computer.
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This paper presents model reduction method of multivariable systems using orthogonal transformation based on aggregation method in time domain. Reduced model which is desisted by presented method preserve stability as relative dominant eigenvalues are selected in original system and obtained computational advantages using orthogonal functions.
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In this paper, an output feedback controller is proposed for continuous time-invariant linear systems. The proposed controller, LQ-FIR consists of an LQ control gain and an optimal FIR filter. The LQ-FIR controller is derived, and the stability of the closed loop system is proved. The bounds of parameter variations guaranteeing the closed loop stability are obtained, when the LQ-FIR controller is applied to the system with model uncertainties.
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In this paper we propose a new method which diagonalize a transfer function matrix. Using it, we can design robust controllers for more MIMO system very easily.
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In this paper, we present a robust
$H^{\infty}$ controller for a state delayed system with uncertainties. The unstructured and norm bounded uncertainties enter into both the state and the input matrix, where the matching condition of the uncertainties is not assumed. A robust stabilization condition and also a robust$H^{\infty}$ stabilization condition are suggested. The robust$H^{\infty}$ controller is obtained by solving a Riccati equation which is derived from the suggested robust$H^{\infty}$ stabilization condition. -
It is a standard problem that designs a controller to minimize the
$H_{\infty}$ -norm of a given plant. By reducing a standard problem to a model-matching problem, we can obtain all the parameters which consist of a controller. After presenting a practical model and applying it to a tracking model, we design an$H_{\infty}$ controller and an LQ controller to concrete that$H_{\infty}$ control theory is far more robust than LQ control theory. And we show the advantage of an$H_{\infty}$ controller by obtaining a desired Bode diagram and comparing it with that of an LQ controller. -
An integral-augmented variable structure system is suggested for the control of an uncertain SISO systems without the reaching phase problems. The integral-augmented sliding surface is defined in order to remove the reaching phase, then it is designed using the optimal technique. The example results show the effectiveness of the algorithm.
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In this paper, the method for designing a robust linear multivariable model following servo system is proposed. This model following servo system for the (n)th order reference input and the (n)th order disturbance is treated, and is designed so that the (n)th order response of the plant should be kept close to the (n)th order response of the given model by LQ(Linear Quadratic) optimal regulator approach. It is proved that the characteristics of the model following servo system is robust in the presence of the disturbances and the parameter perturbations of the plant dynamics.
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This paper presents the general MRAC algorithm design, it's real time implementation and investigates the effect of purely deterministic disturbances to adaptive control algorithm. The design of adaptive control algorithm to reject the disturbances properly is also presented. In real time application, adaptive control algorithm is considered to investigate its performance by using DC motor. Disturbance rejection algorithm is investigated in simulation.
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It is known that Feedback linearization has important limitations-the full state has to be measured; no robustness is guaranteed with respect to parameter uncertainty and unmodeled dynamics. In this paper, we construct a nonlinear feedback linearization controller for the system containing uncertain parameters and unknown states, in the case of EMS system with rail vibration. Performance of this controller is demonstrated by computer simulation.
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The simulated annealing(SA) algorithm is a stochastic strategy for search of the ground state and a powerful tool for optimization. based on the anneal ins process used for the crystallization in physical systems. It's main disadvantage is the long convergence time. Therefore, this paper shows that the new algorithm using SA can be applied to reduce the computation time. This idea has been used to solve the estimation problem of the nonlinear parameter.
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This paper introduces what calibration is and how it is operated. The steps of calibration methods are discussed, which are modeling, measurement, parameter identification and compensation. Using modified D-H model, a new algorithm for parameter identification is developed. This algorithm is very simple and applicable to off-line robot simulator.
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In this paper, a variable structure controller with time-varying sliding surface is proposed for robot manipulators. The proposed time-varying sliding surface ensures the existence of sliding mode from an initial state, while the contentional sliding surface cannot achieve the robust performance against parameter variations and disturbances before the sliding mode occurs. Therefore, error transient can be fully prescribed in advance for all time. Furthermore, it is shown that the overall system is globally exponetially stable. The efficiency of the proposed method for the trajectory tracking has been demonstrated by simulations.
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This paper proposes a method for determining navigation path of an autonomous mobile robot in surrounding environment using a fuzzy algorithm. This fuzzy algorithm includes three type (MIN-TIME, ECONOMY, SAFETY) motion mode for the given robot to get the ability to meet the ambiguous situation which the robot will encounter. Each node is applied to the game situation. This paper conclude with some results of computer simulation concerning an evaluation of this method.
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In this paper, we present an approach to automatically tune and adapt PID parameters by using Fuzzy Logic. PID controllers are well-known and found in many industries. Although the potentials of PID controllers, PID controllers are often poorly tuned and their capabilities are not fully used. We can think that the tuning of PID parameters is based on heuristics and some rule of thumbs. This is the reason we come to use Fuzzy Logic. We show that by imbedding heuristics and some rule of thumbs in PID controllers, reperesented by Fuzzy Logic. we can make PID controllers be robust to uncertainties such as load variations and adapt parameter changes.
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In this thesis, we consider an iterative learning controller to control the continuous trajectory of 2 links direct drive robot manipulator and process computer simulation and real-time experiment. To improve control performance, we adapt an iterative learning control algorithm, drive a sufficient condition for convergence from which is drived extended conventional control algorithm and get better performance by extended learning control algorithm than that by conventional algorithm from simulation results. Also, experimental results show that better performance is taken by extended learning algorithm.
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In this paper we deal with the design and implementation problem of a robust adaptive controller for a direct drive manipulator with unmodeled dynamics. The proposed controller ensures that the closed loop system is stable and output errors are converged to some boundary. To validate the improved performance of the proposed controller experimental results are presented in this paper.
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GoldStar Industrial Systems Co. R & D center successfully developed the inverter for welding under the support of GoldStar Electric Machinery Co. Now, we are currently working on the mechanical part of articulated robot and a high-performance general purpose motion controller. By combining the above three items, we will be able to constitute the complete welding robot system on our own. In this article. the welding robot system currently under developing is introduced. The main focus will be placed on the development of general purpose motion controller with welding control module. Therefore, the architecture of welding robot controller where the general purpose motion controller is combined with the welding controller module will be explained. Here, the software system will be explained with regard to the hardware system.
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In this paper, we derive a simple robust nonlinear control scheme for n-link robot manipulators subject to parameter uncertainty. By using the theory of variable structure system(VSS) and taking advantage of the important property of the robot dynamics, the stability of the derived control scheme is proved. This scheme utilizes the desired trajectory outputs, which can be calculated a priori, instead of the actual joint outputs in the nonlinear compensation controller. So the amount of on-line calculations is largely reduced, and as a result, this scheme can be implemented much more efficiently.
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In this paper, we propose a sensory data combination method by a fuzzy number approach for multisensor data fusion. Generally, the weighting of one sensory data with respect to another is derived from measures of the relative reliabilities of the two sensory modules. But the relative weight of two sensory data can be approximately determined through human experiences or insufficient experimental data without difficulty. We represent these relative weight using appropriate fuzzy numbers as well as sensory data itself. Using the relative weight, which is subjective valuation, and a fuzzy-numbered sensor data, the fuzzy weighted average method is used for a representative sensory data. The manipulation and calculation of fuzzy numbers can be carried out using the Zadeh's extension principle which can be approximately implemented by the
$\alpha$ -cut representation of fuzzy numbers and interval analysis. -
The most important technique for an indoor robot navigation is to find out the direction and the distance from the current location to the destination through the information achieved from the sensor. For this purpose, we suggest sensor-based local homing method which compares the destination sensory data with the current location. As for the sensors, we use the CCD camera and the ultrasonic sensor, and recorded entire 360 degree panoramic data. We match the features of the image data, and the distance and the direction of the matched point will be considered as fuzzy numbers. Through a simple fuzzy arithmetic, we infer the geometric relations between the current location and the destination location.
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The acceleration/deceleration control method and interpolated operating are essential to the servo motor control system. In a few years ago, a floating point DSP chip was used for the purpose of processing a lot of calculated amount. But in this paper, we proposed new acceleration/deceleration control method and circular interpolation algorithm without another floating point DSP chip. The validity of proposed algorithms are verified through computer simulation and experimental result.
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This paper proposes an algorithm to find an optimal trajectory for unspecified paths of the tips of two arms of a dual arm robot. The effective handling a specified object of a dual arm robot closely depends on the effective collision avoidance between parts of robot and the object. For time optimal trajectory without collision, a graphical method is applied for a robot with two degree of freedom. The effectiveness of the proposed method is demonstrated by some simulation results.
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In this paper, an inverse kinematics of redundant manipulators is proposed. Optimality-constraint based inverse kinematic algorithms have some problems because those algorithms are based on necessary conditions for optimality. Among the problems, switching from a maximum value to a minimum value may occur and make an inverse kinematic solution unstable while performing a given task. An inverse kinematic solution for protecting from the switchings is suggested. By sufficient conditions for optimality, the configuration space is defined as a set of regions, potentially good configuration region and potentially bad configuration region. Inverse kinematics solution within potentially good configuration region can provide joint trajectories without both singularities and switchings. Through a simulation of tracing a circle, we show the effectiveness of this inverse kinematics.
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The ultrasonic sensor used in autonomous mobile robot and autonomous guided vehicle(A.G.V.) is not available for long range measurement. And as the performance of autonomous mobile robot and A.G.V. improves, the importance of the range sensor for long range measurement is increasing. In this paper, we introduce the range sensor for long range measurement using milimeter wave sensor and propose the structure of that system.
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Integration of intelligent robot workcell is now a hot issue in CIM and robotics area. This paper dealt with relatively low level essential topics. i. e., multi-robot coordination and real-time communication for the integration of intelligent robot workcell. For the coordination of multi-robot system, the tightly-coupled coordination is proposed using the various sensors. In order to handle the numerous communication data, time-critical communication network (field-bus) is introduced and investigated. Finally, intelligent robot workcell is suggested using the mini-MAP and field-bus.
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Chamferless peg-in-hole process of the cylindrical type parts using force/torque sensor and vision sensor is analyzed and simulated in this paper. Peg-in-hole process is classified to the normal mode (only position error) and tilted mode(position and orientation error). The tilted mode is sub-classified to the small and the big tilted mode according to the relative orientation error. Since the big tilted node happened very rare, most papers dealt with only the normal or the small tilted mode. But the most errors of the peg-in-hole process happened in the big tilted mode. This problem is analyzed and simulated in this paper using the force/torque sensor and vision senor. In the normal mode, fuzzy logic is introduced to combine the data of the force/torque sensor and vision sensor. Also the whole processing algorithms and simulations are presented.
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The methods for stereo matching are divided into two techniques: area-based matching and feature-based matching. To find corresponding points by area-based method, it takes a lot of time because there are many points to be matched. Feature-based matching algorithm is often used because with this method it matches only some feature points so that the processing time is fast even though it requires interpolation after matching. In this paper, we propose the smart technique by which we makes features simpler than conventional methods to match an image pair by feature-based matching algorithm.
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In this paper, we proposed a new FMS Landmark recognition algorithm using color images. Firstly, a NTSC image fame is captured, and then it is converted to a field image in order to reduce the image blurring from the AGV motion. Secondly, the landmark is detected via the comparison of the color vectors of image pixels with the landmark color. Finally, the identification of FMS landmark is executed using a newly designed landmark pattern with a set of reference points. The landmark pattern is normalized against its translation, rotation, and scaling. And then, its vertical projection data are fisted for the pattern classification using the standard data set. Experimental results show that our scheme performs well.
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A real time simulation is an effective tool for use in design, performance evaluation, and testing of the vehicle dynamic system. An alternate approach is to use a computer system designed specifically to provide an integrated simulation environment in which all aspects of hardware-in-the-loop simulation task have been taken into account.
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Main function of distribution automation system can be summarized as feeder automation, telemetering, load control and facility information management. But in most cases, one or two of the above mentioned functions are developed in one distribution automation system. Which function to be developed in the automation system depends on the distribution system's characteristics. The title KODAS means
$\underline{KO}$ rea$\underline{D}$ istribution$\underline{A}$ utomation$\underline{S}$ ystem. Management Korea for KODAS is central control station of distribution system, which is composed of several substations. This paper describes computer system, software tools, data base design data acqusition scheme and information flow. -
In this paper, GIS (Geographical Information System) for KODAS (Korea Distribution Automation System) will be presented. It has been developed to display the status of distribution power line facilities with background geographical map information (eg. address, street, railways and building) and provides various menu screen that can be handled easily. We will discuss computer system I/F between Host computer and GIS, DB structure for GIS and It's functions.
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In this paper, an algorithm for the fault diagnosis using simple FCM(Fuzzy Cognitive Map) is proposed FCMs which store uncertain causal knowledges are fuzzy signed graphs with feedback. The algorithm allows searching the origin of fault and the ways of propagating the abnormality throughout the process simply and has following characteristics. First, it can distinguish the cause of soft failure which can degenerate the process as well as hard failure. Second, it is proper for the processes which have difficulties to establish the exact quantative model. Finally, it has short amputation time in comparison with the fault tree or the other AI methods. The applicability of the proposed algorithm for the fault diagonosis to a tank or pipeline system is demonstrated
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The purpose of this study is to propose a robust OFVSCS that have the robust properties against process parameter variations and external disturbances by extending the basic OFVSCS and to evaluate its control performances. The ROFVSCS is composed of dynamic switching surfaces and output feedback switching control inputs that are constructed by the use of the unknown vector modeling technique. With the proposed scheme. existence of sliding mode is guaranteed and any nonzero bias can be suppressed in the face of disturbances and process parameter variations as far as well-known matching condition is satisfied. Due to the fact that the ROFVSCS is driven by small number of measured information, the practical application of VSCS for the systems with unmeasurable states and for high order systems. that conventional schemes cannot be applied, is possible with the proposed scheme. It is noticeable that implementation cost or VSCS can be considerably reduced without sacrifice of control performances by adopting ROFVSCS since there is no need to measure the states with high measurement cost.
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A rule based fuzzy expert system in self-tune PID controllers is presented in this paper. The rule base. the core of the expert system, is extracted from the Wills' tuning map and the author's knowledge about the implicit relations between PID gains and controlled output response. The overall control system consists of the relay feedback scheme and the expert system, where the one is responsible for initial tuning and the other for subsequent tuning. The PID control system with the proposed fuzzy expert system, shows better convergence rate and control performances than those of a Litt in spite of the fact that the two rule bases are extracted from the same maps provided by Wills.
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A tire tread pattern recognition scheme of which the pattern recognition algorithm is designed based on the fuzzy hierarchical clustering method is proposed and compared with the scheme based on the conventional FCM. The features are extracted from the binary images of the tire tread patterns. In the proposed scheme, the protoypes are obtained more easily and schematically than obtained prototypes using FCM. The experimental results of classification for the practical situations are given and shows the usefulness of the proposed scheme.
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Kim, Eung-Seok;Kim, Kwang-Bae;Choy, Ick;Oh, Sang-Rok;Cho, Young-Jo;Lee, Jun-Soo;Lim, Mee-Seub;Park, Jung-Min;Ahn, Hyun-Sik;Kang, Il-Kwon 442
The design problem of the AGC (Automatic Gauge Control) without a gauge-meter and a load-cell for a reversing rolling mill will be considered in this paper. The proposed controller in this paper is designed using only the linearly approximated relationships between a roll gab, a metal thickness and a pressing force. The data transfer delaying can be released by using these relationships. To show the validity of the proposed control method, the results of the computer simulation and the mathematical analysis will be presented in this paper. -
Digital filter is a signal processor which converts the sequence input sampled from analog signal into another sequence output. It includes software routines which filter digital signal, a computer system for executing the routines, and a data acquisition system which implements A/D, D/A signal conversion. In this paper, a data acquisition system is designed and implemented for one-board computer of MC68000. Also, the theory regarding signal conversion and and its problems occured in implementation are considered. And then, with the hardware implemented like this, design of a digital low-pass filter with the cutoff frequency of 200Hz is implemented, and related characteristics are considered.
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In this study, a method is suggested to design the A/D conversion system which has high resolution to convert load cell signal. First, hardware was designed to reduce the offset voltage of integrator and comparator. And then, a calibration software technique was performed to obtain the stable data from A/D converter. The optimal parameters of each elements in the circuits was selected using the SPICE simulation. The main advantage of our method is high precision A/D converter can be constructed with low cost and high confidence. Therefore proposed method is expected to be used in the industrial field where a high precision measurement is required.
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In this research, the digital signal processing PC board which employs TI's TMS320C25 is implemented. The board can perform following functions. spectrum analysis of speech and repetitive signal, digital filters emulation by convolution, signal generation of sinusoidal wave, rectangular wave etc.. In this system, communications between PC and DSP board. program down-loading to DSP board and recording and graphic of acquired and processed data in DSP board are executed by PC. Parallel interface and buffer memory are used in communications. Data acquisition and operation are carried out in DSP board. Resultant data are transmitted to PC and output through DAC.
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A new filter-bank is proposed in order to track center frequency of narrow bard signal. The filter-bark proposed here has a laster and a slave filter bark. The two barks are connected in series-parallel. The master filter bank which is made of traditional filter bank detects the center frequency roughly. And the performance for tracking center frequency is greatly improved by the slave filter bank which is based or energy-difference estimator. Computer simulations show that it achieves a good tracking accuracy.
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In this paper, The laser transmitter module is designed as the subsystem of the high repetitive laser rangefinder. The module consists of high voltage power supply, high voltage control circuits, high voltage discharger, electro-optic Q-switch driver, and laser resonator. The high voltage power supply is composed of 2-phase flyback converter. And it has 220W power level and 78% conversion efficiency. From the Q-switch driver of the crossed porro resonator, the phase retardation voltage is switched from 600V to -1500V with 200ns falling time. The module can be operated up to 15Hz. And it generates the laser pulse which has 20ns width and 80mJ.
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In this paper, a peak detection algorithm having high reliability is proposed. The peak detection algorithm is implemented to a charger and power control system which is applicable to home appliances or notebook PC directly. The charger and power control system is controlled by a microprocessor, M50927 (Mitzubishi), to improve cost to performance ratio. The charger algorithm is designed to be operated under optimal charge node and various protections are added tn improve the reliability of the charger.
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To analyze dynamic characteristics for a motorcar, the creation and the hammering test methods are introduced. This paper has studied the method of computing the natural frequency of the impulse wave on a tire, the decay constant which determines the absorption capability for the impulsive force. Moreover we have examined the reliability for the decay constant calculated, in this paper theoritical results are agreed with the simulated ones.
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Nowadays, according to gradual progress of the information oriented society, it is being increase rapidly that social requirement for the high quality and stability of electric power supply. Therefore, for the sake of expansion of the various power system and reasonable operation and administration, there are some growing need for telecommunication system that will operate in high dependability performance and expansion by much. But beause of unestablished reliability analysis and evaluation methodology for power telecommunication system, it could not have a reasonable planning for the purpose of improving dependability performance on telecommunication system. The object of this study is to construct reasonable methodology of reliability evaluation fur the efficient power telecommunication facility administration.
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Premium Service is the next service to be developed after the Freephone Service and Credit Call Service which has currently been developed and is being now tested. Premium Service is a service which provide information on a telephone line. The calls are charged with a special rate which includes service and call charge. Public telecommunication operator performs charging and accounting from the service user for the service provider and for every service provided subtracts the commission from the part of service revenue and gives the rest back to the service provider. This paper is about the study on the implementation of the Premium Service in the Service Switching Point.
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Instead of installing new communication wiring to each house in the apartment house building. the power distribution network. which is already installed in the building. can be use as communication medium. In a safty management, by adoption of power line communication system, at remote we can monitor safty related sensors such as fire, gas leakage, burglar intrusion and emergency call which are located at each house. From this viewpoint, we developed security monitoring system for apartment house building using power lines. Security monitoring system consists of Power Line Communication-Sub Controller (PLC-SC). Power Line Communication-Main Controller (PLC-MC) and Management System (MS). Between a PLC-MC and a PLC-SC, the transmission rate is 1200 bps in power lines and modulation technique is frequency shirt keying (FSK). In between a PLC-MC and a MS, the transmission rate is 1200 bps in communication line (RS-485). As a result of this research. transmission loss is 0.1dB per meter of intrabuilding distribution network. Transmission can be reach in 250 meters. So it is enough to communicate for security monitoring system in apartment house building.
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A fully balanced differential amplifier can achieve high-gain wide-bandwidth characteristics. And also, Offset PSRR, CMRR and Noise performance of that are excellent, but these merits can be achieved only when the architecture holds fully balanced. Commonly, the fully balanced differential amplifier has a common mode feedback(CMFB) circuit in order to maintain the balance. This paper presents improved characteristics of the CMFB circuit and designs the wide-bandwidth CMOS Op-amp. The unity gain bandwidth of this Op-amp is 50MHz with the load capacitor 2pF, and the value of phase margin is
$85^{\circ}$ . -
Fuzzy Logic Control immitating human decision making process is a novel control strategy based on expert's experience and knowledge and many process designers are developing its applications. But it is difficult to obtain a set of ruler from human operators. And there is a limitation on adjusting to environmental changes. In this paper, we proposed adaptive fuzzy algorithm to overcome these difficulties using weights added to the rules. To verify the validity of this control strategy, we have implemented this algorithm for a DC servo motor with PD-type fuzzy controller.
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Many optimization problem or multiple attribute, multiple alternative decision making problem may have fuzzy evaluation factors. In this case, fuzzy number operation technique is needed to evaluate and compare object functions which become fuzzy sets. Generally, fuzzy number operations can be defined by extension principle of fuzzy set theory, but it is tedious to do fuzzy number operations by using extension principle when the membership functions are defined by complex functions. Many fast methods which approximate the membership functions such as triangle, trapezoidal, or L-R type functions are proposed. In this paper, a fast fuzzy number operation method is proposed which do not simplify the membership functions of fuzzy numbers.
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CMAC (Cerebeller Model Articulation Controller) is kind of Neural Networks that imitate the human cerebellum. For storage and retrieval of learned data, the input of CMAC is used as a key to determine the memory location. he learned information is distributively stored in physical memory. The learning of CMAC is very fast and converged well, therefore, it effects the application of Pattern Recognition. Through the our experiment of Pattern Recognition, we will prove that CMAC is very suitable for On-line real time processing and incremental learning of Neural Networks.
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This paper presents spoken numbers recognition method using a spatio-temporal network This network is efficient in processing the spectrum sequences of speech patterns as spatio-temporal patterns. The number of windows and channels is experimentally determined. The recognition rate has been improved by experiments done on various parameters. The test data is collected form 10 numbers spoken by 2 male and female speakers. A recognition rate of 80% was obtained on a test set of 50 words.
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This paper presents handover algorithm method using fuzzy rules and neura1 network. In future mobile communication systems, the amount of call requests over a region will increase dramatically. This problem has to be solved by decreasing the cell size. But, this method lets a mobile station switch the a base station at a higher rate. In order to maintain better mobile communication system in a micro or pico cellular system, better handover algorithm must be devoloped. In this paper, we propose a handover algorithm which is based on the fuzzy teory that is applied to make rules with the parameters and neural network that is to learn rules. This new handover algorithm is tested by computer simulation and compared with the conventional algorithms.
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A circuit of sigmoid function for neural network is designed by using Piecewise Linear (PWL) method. The slope of sigmoid function can be adjusted to 2 and 0.25. Also the circuit presents both sigmoid function and its differential form. The circuits is simulated by using ViewLogic. Theoretical and simulated performance agree with 1.8 percent.
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JPEG(Joint Photographic Experts Group) 표준안은 디지털 정지 압축을 위하여 국제표준화기구(ISO/SC29/WG10)와 국제전신전화 자문회의(CCITT SG VIII)에 의해서 제안되었다. JPEG 표준안은 전자영상, 컴퓨터 그래픽, 멀티미디어 등과 관련하여 널리 응용되고 있으나, 의료 영상분야에서는 JPEG 압축의 손실 특성 때문에 사용이 매우 제한적이었다. 본 논문에서는 JPEG 표준안을 핵자기 공명 단층 영상 (256 gray levels,
$256{\times}256$ size) 압축에 적용하여 그 성능을 조사하였다. 이를 위하여 JPEG 표준안 중 DCT에 기반을 둔 순차식 부호화 압축을 C-Cube Microsystems의 CL550 chip을 사용하여 구현하였고, 점진식 및 무손실 부호화 방식은 특별한 Hardware 없이 Software로 구현하여 실험하였다. 본 실험을 통하여 핵자기 공명 단층 시험 영상에 대해 거의 왜곡없이 약 10-20 정도의 압축률이 얻어짐을 확인할 수 있었다. 특히 JPEG으로 압축하였을 경우 재구성한 영상과 원영상과의 에러 신호가 random noise에 가깝게 나타남으로써 특별한 artifact가 없는 것도 JPEG의 큰 장점으로 부각된다. 한편 JPEG의 점진식 및 게층식 부호화 방식은 압축률과 신호대 잡음비에 있어서는 순차식과 동일하나, 거대한 영상 데이터 베이스 내에서의 빠른 탐색과 비교적 속도가 느린 공중망을 통한 원격 진단에 유용한 특성을 갖는다. -
The monitor program, which controls overall operation of MC68000 based system and executes some commands and I/O operations, is a system program and consists of functions that executes these operations. Monitor program can be easily applied to design a digital filter. This paper approaches to the object, to which refer above, by considerng algorithm of monitor program, which operates in M68000 based system, and concerning theory. This monitor program operate by the serial communication between host IBM-PC and target MC68000 system with MC6850 and MAX232C.
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The weighted median hybrid filters are proposed. These filters take weighting factors in calculating the output of subfilters of median hybrid filters. The properties of weighted median hybrid filters are analysed and compared to the conventional median filter. The results indicate that these filters preserve details of edge better than and are computationally much more efficient than conventional median filter.
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Dispatcher's Training simulation function are network analysis, power system modeling, supervisory control, and system security assessment. This function provides hand-on training for power dispatchers for operation of the nation control center in the future, it needs interface between simulator and expert system. This paper introduces DTS function which is adopted in the Central Load Dispatching Office.
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AS THE POWER SYSTEM BECOMES LARGER AND MORE COMPLICATED, THE NUMBER OF UNEXPLAINABLE FAULTS IS INCREASING. IN ORDER TO EXPLAIN THESE FAULTS, NUMEROUS AND VARIOUS DATA ARE NEEDED. BUT THESE DATA ARE NOT READILY AVAILABLE FROM THE FIELD TEST, SO SHOULD BE OBTAINED FROM THE SIMULATOR WHICH CAN SIMULATE THE POWER SYSTEM EXACTLY AND EASILY. IN THIS PAPER, A DIGITAL SIMULATOR WHICH IS APPROPRIATE FOR THIS PURPOSE IS DEVELOPED. THIS SIMULATOR IS DIVIDED INTO THREE PARTS : DIGITAL SIMULATION PART, D/A CONVERSION AND CONTROL PART AND AMPLIFIER PART. AND, THE FUNCTION OF THE SIMULATOR AND THE FUTURE RESEARCH AREA ARE DISCUSSED.
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This paper discusses the training simulator designed to improve the skills of operators who handle the SCADA System of KEPCO (Korea Electric Power Co. ). The system is composed of the simulation subsystem and database, and implemented on the 380-based P. C. It is 1 inked to existing SCADA system (HARRIS and TADCOM) to work realistically for the situation of accidents and corresponding actions.
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The Status of Power Plant Simulation Technology and KEPCO's Plan for Self-Reliance of the TechnologyKEPCO Research Center is carrying out a simulator(full scope replica type) development project for two nuclear power plants(Kori-2, Younggwang-3,4) and one fossil power plant(Poryong-3,4). In this project, we aim not only the installation of high performance simulators at the power plant sites but also the realization of self reliance of power plant simulation technology in Korea. In the course of preparing procurement specification for the 3 simulators, the present status of power plant simulation technology has been surveyed and is presented in this paper. The fidelity of simulation and the automation of simulation model production has been greatly improved due to the ever increasing computing power of today's workstations. The need and importance of the application of high fidelity simulators to the operator training is refocused since the accident at TMI Nuclear Power Plant, U.S.A.
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Recently, the analysis of power systems is transfering from analytical techniques to simulation because it is difficult to analyze accurately the phenomena occured in complicated and huge power systems. Digital computers are used popularly to analyze the phenomena of power systems. But real-time simulators were used due to the limitation of digital computer - real time analysis, non-linearity and so on - and rapid development of digital technologies. In this paper, we discuss the advanced foreign power system simulators and the conceptual designs for the KEPCO power system simulator have been drawn for the domestic development.