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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Electrical Engineering and Technology
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Journal DOI :
The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 7, Issue 6 - Nov 2012
Volume 7, Issue 5 - Sep 2012
Volume 7, Issue 4 - Jul 2012
Volume 7, Issue 3 - May 2012
Volume 7, Issue 2 - Mar 2012
Volume 7, Issue 1 - Jan 2012
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Power Sharing Method for a Grid connected Microgrid with Multiple Distributed Generators
Nguyen, Khanh-Loc ; Won, Dong-Jun ; Ahn, Seon-Ju ; Chung, Il-Yop ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 459~467
DOI : 10.5370/JEET.2012.7.4.459
In this paper, a grid connected microgrid with multiple inverter-based distributed generators (DGs) is considered. DG in FFC mode regulates the microgrid as a controllable load from the utility point of view as long as its output is within the capacity limit. The transition mode causes a change in frequency of microgrid due to the loss of power transferred between main grid and microgrid. Frequency deviation from the nominal value can exceed the limit if the loss of power is large enough. This paper presents a coordinated control method for inverter-based DGs so that the microgrid is always regulated as a constant load from the utility viewpoint during grid connected mode, and the frequency deviation in the transition mode is minimized. DGs can share the load by changing their control modes between UPC and FFC and stabilize microgrid during transition.
Market-Based Transmission Expansion Planning Under Uncertainty in Bids by Fuzzy Assessment
Kamyab, Gholam-Reza ; Fotuhi-Firuzabad, Mahmood ; Rashidinejad, Masoud ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 468~479
DOI : 10.5370/JEET.2012.7.4.468
In this paper, by a simple example it is shown that existing market-based criteria alone cannot completely and correctly evaluate the transmission network expansion from market view. However criteria congestion cost (CC) and social welfare (SW) together are able to correctly evaluate transmission network from market view and so they are adopted for the market-based transmission expansion planning. To simply indicate the limits of CC and SW social welfare percentage (SWP) and congestion cost percentage (CCP) are defined. To consider uncertainty in bids of market producers and consumers, and also indeterminacy in the acceptable boundaries of the SWP and CCP and their priorities, fuzzy assessment approach is used. In this approach, appropriate fuzzy sets and a fuzzy rule base are provided to evaluate the acceptability of an expansion plan. Then, the least-investment cost plan, which is acceptable in all probable scenarios, is searched. The proposed method is applied to an 8-bus system.
Analysis of Stability of PV System using the Eigenvalue according to the Frequency Variation and Requirements of Frequency Protection
Seo, Hun-Chul ; Kim, Chul-Hwan ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 480~485
DOI : 10.5370/JEET.2012.7.4.480
Use of photovoltaic (PV) power generation system will become more widespread in the future due to anticipated cost reduction in PV technology. As the capacity of PV systems increases, a variation of power system frequency may prevent the stable output of PV system. However, the standard for the frequency protection of distributed generation in Korea Electric Power Corporation (KEPCO)'s rule does not include the setting of frequency protection. Therefore, this paper analyzes the correlation between the frequency protection requirements and the stability of grid-connected PV system for the adjustable operating setting of frequency protection. The distribution system interconnected with 3 MW PV system is modeled by Matlab/Simulink. The various values of frequency are simulated. For studied cases, the stability of PV system is analyzed. It is concluded that the setting of frequency protection is necessary to consider the stability of PV system.
Distribution System Reconfiguration Considering Customer and DG Reliability Cost
Cho, Sung-Min ; Shin, Hee-Sang ; Park, Jin-Hyun ; Kim, Jae-Chul ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 486~492
DOI : 10.5370/JEET.2012.7.4.486
This paper presents a novel objective function for distribution system reconfiguration for reliability enhancement. When islanding operations of distributed generators is prohibited, faults in the feeder interrupt the operation of distributed generators. For this reason, we include the customer interruption cost as well as the distributed generator interruption cost in the objective function in the network reconfiguration algorithm. The network reconfiguration in which genetic algorithms are used is implemented by MATLAB. The effect of the proposed objective function in the network reconfiguration is analyzed and compared with existing objective functions through case studies. The network reconfiguration considering the proposed objective function is suitable for a distribution system that has a high penetration of distributed generators.
Performance Comparison of GA, DE, PSO and SA Approaches in Enhancement of Total Transfer Capability using FACTS Devices
Chandrasekar, K. ; Ramana, N.V. ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 493~500
DOI : 10.5370/JEET.2012.7.4.493
In this paper the performance of meta-heuristics algorithms such as GA (Genetic Algorithm), DE (Differential Evolution), PSO (Particle Swarm Optimization) and SA (Simulated Annealing) for the problem of TTC enhancement using FACTS devices are compared. In addition to that in the assessment procedure of TTC two novel techniques are proposed. First the optimization algorithm which is used for TTC enhancement is simultaneously used for assessment of TTC. Second the power flow is done using Broyden - Shamanski method with Sherman - Morrison formula (BSS). The proposed approach is tested on WSCC 9 bus, IEEE 118 bus test systems and the results are compared with the conventional Repeated Power Flow (RPF) using Newton Raphson (NR) method which indicates that the proposed method provides better TTC enhancement and computational efficacy than the conventional procedure.
Optimal Particle Swarm Based Placement and Sizing of Static Synchronous Series Compensator to Maximize Social Welfare
Hajforoosh, Somayeh ; Nabavi, Seyed M.H. ; Masoum, Mohammad A.S. ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 501~512
DOI : 10.5370/JEET.2012.7.4.501
Social welfare maximization in a double-sided auction market is performed by implementing an aggregation-based particle swarm optimization (CAPSO) algorithm for optimal placement and sizing of one Static Synchronous Series Compensator (SSSC) device. Dallied simulation results (without/with line flow constraints and without/with SSSC) are generated to demonstrate the impact of SSSC on the congestion levels of the modified IEEE 14-bus test system. The proposed CAPSO algorithm employs conventional quadratic smooth and augmented quadratic nonsmooth generator cost curves with sine components to improve the accurate of the model by incorporating the valve loading effects. CAPSO also employs quadratic smooth consumer benefit functions. The proposed approach relies on particle swarm optimization to capture the near-optimal GenCos and DisCos, as well as the location and rating of SSSC while the Newton based load flow solution minimizes the mismatch equations. Simulation results of the proposed CAPSO algorithm are compared to solutions obtained by sequential quadratic programming (SQP) and a recently implemented Fuzzy based genetic algorithm (Fuzzy-GA). The main contributions are inclusion of customer benefit in the congestion management objective function, consideration of nonsmooth generator characteristics and the utilization of a coordinated aggregation-based PSO for locating/sizing of SSSC.
LMI-based Sliding Mode Speed Tracking Control Design for Surface-mounted Permanent Magnet Synchronous Motors
Leu, Viet Quoc ; Choi, Han-Ho ; Jung, Jin-Woo ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 513~523
DOI : 10.5370/JEET.2012.7.4.513
For precisely regulating the speed of a permanent magnet synchronous motor system with unknown load torque disturbance and disturbance inputs, an LMI-based sliding mode control scheme is proposed in this paper. After a brief review of the PMSM mathematical model, the sliding mode control law is designed in terms of linear matrix inequalities (LMIs). By adding an extended observer which estimates the unknown load torque, the proposed speed tracking controller can guarantee a good control performance. The stability of the proposed control system is proven through the reachability condition and an approximate method to implement the chattering reduction is also presented. The proposed control algorithm is implemented by using a digital signal processor (DSP) TMS320F28335. The simulation and experimental results verify that the proposed methodology achieves a more robust performance and a faster dynamic response than the conventional linear PI control method in the presence of PMSM parameter uncertainties and unknown external noises.
Control of a Novel PV Tracking System Considering the Shadow Influence
Ko, Jae-Sub ; Chung, Dong-Hwa ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 524~529
DOI : 10.5370/JEET.2012.7.4.524
This paper proposes a novel control strategy of a PV tracking system considering the shadow influence. If distance of between PV arrays is not enough, shadow can be occurred to PV module. In PV system, if shadow is occurred to PV modules then PV modules operates reverses bias, and will eventually cause hot-spot and loss. To reduce loss by shadow influence, this paper proposes shadow compensation algorithm using distance between arrays and shadow length of array. The distance between arrays is calculated by using azimuth of solar, and length of array shadow is calculated using by altitude of solar. The shadow compensation algorithm proposed in this paper compares distance between arrays and length of array shadow. When the shadow length is longer than the distance between arrays, the algorithm adjusts altitude of array to avoid the shadow effects. The control algorithm proposed in this paper proves validity through compared with conventional algorithm and proposes experiment result.
Optimal Rotor Structure Design of Interior Permanent Magnet Synchronous Machine based on Efficient Genetic Algorithm Using Kriging Model
Woo, Dong-Kyun ; Kim, Il-Woo ; Jung, Hyun-Kyo ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 530~537
DOI : 10.5370/JEET.2012.7.4.530
In the recent past, genetic algorithm (GA) and evolutionary optimization scheme have become increasingly popular for the design of electromagnetic (EM) devices. However, the conventional GA suffers from computational drawback and parameter dependency when applied to a computationally expensive problem, such as practical EM optimization design. To overcome these issues, a hybrid optimization scheme using GA in conjunction with Kriging is proposed. The algorithm is validated by using two mathematical problems and by optimizing rotor structure of interior permanent magnet synchronous machine.
Reduction of Components in Cascaded Transformer Multilevel Inverter Using Two DC Sources
Banaei, Mohamad Reza ; Salary, Ebrahim ; Alizadeh, Ramin ; Khounjahan, Hossein ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 538~545
DOI : 10.5370/JEET.2012.7.4.538
In this paper a novel cascaded transformer multilevel inverter is proposed. Each basic unit of the inverter includes two DC sources, single phase transformers and semiconductor switches. This inverter, which operates as symmetric and asymmetric, can output more number of voltage levels in the same number of the switching devices. Besides, the number of gate driving circuits is reduced, which leads to circuit size reduction and lower power consumption in the driving circuits. Moreover, several methods to determination of transformers turn ratio in proposed inverter are presented. Theoretical analysis, simulation results using MATLAB/SIMULINK and experimental results are provided to verify the operation of the suggested inverter.
Intelligent Control for Torque Ripple Minimization in Combined Vector and Direct Controls for High Performance of IM Drive
Boulghasoul, Zakaria ; Elbacha, Abdelhadi ; Elwarraki, Elmostafa ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 546~557
DOI : 10.5370/JEET.2012.7.4.546
In Conventional Combined Vector and Direct Controls (VC-DTC) of induction motor, stator current is very rich in harmonic components. It leads to high torque ripple of induction motor in high and low speed region. To solve this problem, a control method based on the concept of fuzzy logic approach is used. The control scheme proposed uses stator current error as variable. Through the fuzzy logic controller rules, the choice of voltage space vector is optimized and then torque and speed are controlled successfully with a less ripple level in torque response, which improve the system's performance. Simulation results trough MATLAB/SIMULINK
software gave results that justify the claims.
Experiments of a Novel Magnetic Levitation Stage for Wide Area Movements
Jeon, Jeong-Woo ; Caraiani, Mitica ; Oh, Hyeon-Seok ; Kim, Sung-Shin ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 558~563
DOI : 10.5370/JEET.2012.7.4.558
In this paper, a novel planar type magnetic levitation system without other assistant devices is proposed and it can move with 6 degree of freedom (X, Y, Z,
) in wafer size as well as in nano scale positioning.The mover is composed with 2-D Halbach permanent magnet array and the stator is composed with
coil arrays.It was composed in laboratory and tested with short stroke (4 [mm]) and long stroke (160 [mm])movements. The errors of short movement test is [X, Y, Z,
]The errors of long stroke movement test is [X, Y, Z,
Levitation and Thrust Forces Analysis of Hybrid-Excited Linear Synchronous Motor for Magnetically Levitated Vehicle
Cho, Han-Wook ; Kim, Chang-Hyun ; Han, Hyung-Suk ; Lee, Jong-Min ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 564~569
DOI : 10.5370/JEET.2012.7.4.564
This paper proposes a hybrid-excited linear synchronous motor (LSM) that has potential applications in a magnetically levitated vehicle. The levitation and thrust force characteristics of the LSM are investigated by means of three-dimensional (3-D) numerical electromagnetic FEM calculations and experimental verification. Compared to a conventional LSM with electromagnets, a hybrid-excited LSM can improve levitation force/weight ratios, and reduce the power consumption of the vehicle. Because the two-dimensional (2-D) FE analysis model describes only the center section of the physical device, it cannot express the complex behavior of leakage flux, which this study is able to predicts along with levitation and thrust force characteristics by 3-D FEM calculations. A static force tester for a hybrid-excited LSM has been manufactured and tested in order to verify these predictions. The experimental results confirm the validity of the 3-D FEM calculation scheme for the description of a hybrid-excited LSM.
A Novel Modeling and Performance Analysis of Imperfect Quadrature Modulator in RF Transmitter
Park, Yong-Kuk ; Kim, Hyeong-Seok ; Lee, Ki-Sik ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 570~575
DOI : 10.5370/JEET.2012.7.4.570
In a wireless communication RF transmitter, the output of a quadrature modulator (QM) is distorted by not only the linear imperfection features such as in/quadrature-phase (I/Q) input gain imbalance, local phase imbalance, and local gain imbalance but also the nonlinear imperfection features such as direct current (DC) offset and mixer nonlinearity related to in-band spurious signal. In this paper, we propose the unified QM model to analyze the combined effects of the linear and nonlinear imperfection features on the performance of the QM. The unified QM model consists of two identical nonlinear systems and modified I/Q inputs based on the two-port nonlinear mixer model. The unified QM model shows that the output signals can be expressed by mixer circuit parameters such as intercept point and gain as well as the imperfection features. The proposed approach is validated by not only simulation but also measurement.
Cutting Technique for Biodegradable Rope using a CW CO
Laser with TEM
Lee, Dong-Gil ; Kim, Seong-Hun ; Park, Seong-Wook ; Yang, Yong-Su ; Xu, Guo-Cheng ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 576~581
DOI : 10.5370/JEET.2012.7.4.576
A 23 W continuous wavelength
laser system exited by a high-frequency LCC resonant converter is adapted to cut a biodegradable rope fabricated with polybutylene succinate. As the biodegradable rope consists of three twisted strands, the thickness changes relative to the position of the laser beam and we thus propose a method to determine exact cutting depth. In order to obtain the parameters related to the rope cutting, the experimental and theoretical cutting depths are compared and analyzed for a range of laser heat sources. The melted thickness and groove width of the cut biodegradable rope are also examined. The proposed theoretical cutting depth depends on the incident power and target velocity ratio. From these experimental results, the biodegradable rope with a diameter of 22 mm can be cut with a heat source of 50 J/cm resulting in a melted thickness of 1.96 mm and a groove width of 0.65 mm. The laser system is shown to be perfect tool for the processing of biodegradable rope without the occurrence of raveling.
Highly Miniaturized and Performed UWB Bandpass Filter Embedded into PCB with SrTiO
Cheon, Seong-Jong ; Park, Jun-Hwan ; Park, Jae-Yeong ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 582~588
DOI : 10.5370/JEET.2012.7.4.582
In this paper, a highly miniaturized and performed UWB bandpass filter has been newly designed and implemented by embedding all the passive elements into a multi-layered PCB substrate with high dielectric
composite film for 3.1 - 4.75 GHz compact UWB system applications. The high dielectric composite film was utilized to increase the capacitance densities and quality factors of capacitors embedded into the PCB. In order to reduce the size of the filter and avoid parasitic EM coupling between the embedded filter circuit elements, it was designed by using a
order Chebyshev circuit topology and a capacitive coupled transformation technology. Independent transmission zeros were also applied for improving the attenuation of the filter at the desired stopbands. The measured insertion and return losses in the passband were better than 1.68 and 12 dB, with a minimum value of 0.78 dB. The transmission zeros of the measured response were occurred at 2.2 and 5.15 GHz resulting in excellent suppressions of 31 and 20 dB at WLAN bands of 2.4 and 5.15 GHz, respectively. The size of the fabricated bandpass filter was
Frequency-dependent grounding impedance of the counterpoise based on the dispersed currents
Choi, Jong-Hyuk ; Lee, Bok-Hee ; Paek, Seung-Kwon ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 589~595
DOI : 10.5370/JEET.2012.7.4.589
When surges and electromagnetic pulses from lightning or power conversion devices are considered, it is desirable to evaluate grounding system performance as grounding impedance. In the case of large-sized grounding electrodes or long counterpoises, the grounding impedance is increased with increasing the frequency of injected current. The grounding impedance is increased by the inductance of grounding electrodes. This paper presents the measured results of frequency-dependent grounding impedance and impedance phase as a function of the length of counterpoises. In order to analyze the frequency-dependent grounding impedance of the counterpoises, the frequency-dependent current dissipation rates were measured and simulated by the distributed parameter circuit model reflecting the frequency-dependent relative resistivity and permittivity of soil. As a result, the ground current dissipation rate is proportional to the soil resistivity near the counterpoises in a low frequency. On the other hand, the ground current dissipation near the injection point is increased as the frequency of injected current increases. Since the high frequency ground current cannot reach the far end of long counterpoise, the grounding impedance of long counterpoise approaches that of the short one in the high frequency. The results obtained from this work could be applied in design of grounding systems.
Highly transparent and resistive nanocrystalline ZnO-SnO
films prepared by rf magnetron sputtering
Cha, Chun-Nam ; Choi, Mu-Hee ; Ma, Tae-Young ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 596~600
DOI : 10.5370/JEET.2012.7.4.596
films were deposited by rf magnetron sputtering using a ZnO-
(2:1 molar ratio) target. The target was made from a mixture of ZnO and
powders calcined at
. The working pressure was 1 mTorr, and the rf power was 120 W. The ratio of oxygen to argon (
:Ar) was varied from 0% to 10%, and the substrate temperature was varied from
. The crystallographic properties and the surface morphologies of the films were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force spectroscopy (AFM). The ZnO-
films deposited in
:Ar = 10% exhibited resistivity higher than
and transmittance of more than 80% in the visible range.
A Study on the Design and Electrical Characteristics Enhancement of the Floating Island IGBT with Low On-Resistance
Jung, Eun-Sik ; Cho, Yu-Seup ; Kang, Ey-Goo ; Kim, Yong-Tae ; Sung, Man-Young ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 601~605
DOI : 10.5370/JEET.2012.7.4.601
Insulated Gate Bipolar Transistors(IGBTs) have received wide attention because of their high current conduction and good switching characteristics. To reduce the power loss of IGBT, the onstate voltage drop should be lowered and the switching time should be shortened. However, there is trade-off between the breakdown voltage and the on-state voltage drop. The FLoatingIsland(FLI) structure can lower the on-state voltage drop without reducing breakdown voltage. In this paper, The FLI IGBT shows an on-state voltage drop that is 22.5% lower than the conventional IGBT, even though the breakdown voltages of each IGBT are almost identical.
Performance Analysis of the Robust Least Squares Target Localization Scheme using RDOA Measurements
Choi, Ka-Hyung ; Ra, Won-Sang ; Park, Jin-Bae ; Yoon, Tae-Sung ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 606~614
DOI : 10.5370/JEET.2012.7.4.606
A practical recursive linear robust estimation scheme is proposed for target localization in the sensor network which provides range difference of arrival (RDOA) measurements. In order to radically solve the known practical difficulties such as sensitivity for initial guess and heavy computational burden caused by intrinsic nonlinearity of the RDOA based target localization problem, an uncertain linear measurement model is newly derived. In the suggested problem setting, the target localization performance of the conventional linear estimation schemes might be severely degraded under the low SNR condition and be affected by the target position in the sensor network. This motivates us to devise a new sensor network localization algorithm within the framework of the recently developed robust least squares estimation theory. Provided that the statistical information regarding RDOA measurements are available, the estimate of the proposition method shows the convergence in probability to the true target position. Through the computer simulations, the omnidirectional target localization performance and consistency of the proposed algorithm are compared to those of the existing ones. It is shown that the proposed method is more reliable than the total least squares method and the linear correction least squares method.
Attitude Determination GPS/INS Integration System Design Using Triple Difference Technique
Oh, Sang-Heon ; Hwang, Dong-Hwan ; Park, Chan-Sik ; Lee, Sang-Jeong ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 615~625
DOI : 10.5370/JEET.2012.7.4.615
GPS attitude outputs or carrier phase observables can be effectively utilized to compensate the attitude error of the strapdown inertial navigation system. However, when the integer ambiguity is not correctly resolved and/or a cycle slip occurs, an erroneous GPS output can be obtained. If the erroneous GPS output is applied to the attitude determination GPS/INS (ADGPS/INS) integrated navigation system, the performance of the system can be degraded. This paper proposes an ADGPS/INS integration system using the triple difference carrier phase observables. The proposed integration system contains a cycle slip detection algorithm, in which the inertial information is combined. Computer simulations and flight test were performed to verify effectiveness of the proposed navigation system. Results show that the proposed system gives an accurate and reliable navigation solution even when the integer ambiguity is not correctly resolved and the cycle slip occurs.
Elimination of Clock Jump Effects in Low-Quality Differential GPS Measurements
Kim, Hee-Sung ; Lee, Hyung-Keun ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 626~635
DOI : 10.5370/JEET.2012.7.4.626
Most of single frequency GPS receivers utilize low-quality crystal oscillators. If a lowquality crystal oscillator is utilized as the time reference of a GPS receiver, the receiver's clock bias grows very fast due to its inherent low precision and poor stability. To prevent the clock bias becoming too large, large clock jumps are intentionally injected to the clock bias and the time offset for clock steering purpose. The abrupt changes in the clock bias and the time offset, if not properly considered, induce serious accuracy degradation in relative differential positioning. To prevent the accuracy degradation, this paper proposes an efficient and systematic method to eliminate the undesirable clock jump effects. Experiment results based on real measurements verify the effectiveness of the propose method.
Multiobjective Space Search Optimization and Information Granulation in the Design of Fuzzy Radial Basis Function Neural Networks
Huang, Wei ; Oh, Sung-Kwun ; Zhang, Honghao ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 636~645
DOI : 10.5370/JEET.2012.7.4.636
This study introduces an information granular-based fuzzy radial basis function neural networks (FRBFNN) based on multiobjective optimization and weighted least square (WLS). An improved multiobjective space search algorithm (IMSSA) is proposed to optimize the FRBFNN. In the design of FRBFNN, the premise part of the rules is constructed with the aid of Fuzzy C-Means (FCM) clustering while the consequent part of the fuzzy rules is developed by using four types of polynomials, namely constant, linear, quadratic, and modified quadratic. Information granulation realized with C-Means clustering helps determine the initial values of the apex parameters of the membership function of the fuzzy neural network. To enhance the flexibility of neural network, we use the WLS learning to estimate the coefficients of the polynomials. In comparison with ordinary least square commonly used in the design of fuzzy radial basis function neural networks, WLS could come with a different type of the local model in each rule when dealing with the FRBFNN. Since the performance of the FRBFNN model is directly affected by some parameters such as e.g., the fuzzification coefficient used in the FCM, the number of rules and the orders of the polynomials present in the consequent parts of the rules, we carry out both structural as well as parametric optimization of the network. The proposed IMSSA that aims at the simultaneous minimization of complexity and the maximization of accuracy is exploited here to optimize the parameters of the model. Experimental results illustrate that the proposed neural network leads to better performance in comparison with some existing neurofuzzy models encountered in the literature.
New Watermarking Technique Using Data Matrix and Encryption Keys
Kim, Il-Hwan ; Kwon, Chang-Hee ; Lee, Wang-Heon ;
Journal of Electrical Engineering and Technology, volume 7, issue 4, 2012, Pages 646~651
DOI : 10.5370/JEET.2012.7.4.646
Meaningful logos or random sequences have been used in the current digital watermarking techniques of 2D bar code. The meaningful logos can not only be created by copyright holders based on their unique information, but are also very effective when representing their copyrights. The random sequences enhance the security of the watermark for verifying one's copyrights against intentional or unintentional attacks. In this paper, we propose a new watermarking technique taking advantage of Data Matrix as well as encryption keys. The Data Matrix not only recovers the original data by an error checking and correction algorithm, even when its high-density data storage and barcode are damaged, but also encrypts the copyright verification information by randomization of the barcode, including ownership keys. Furthermore, the encryption keys and the patterns are used to localize the watermark, and make the watermark robust against attacks, respectively. Through the comparison experiments of the copyright information extracted from the watermark, we can verify that the proposed method has good quality and is robust to various attacks, such as JPEG compression, filtering and resizing.