• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.04a
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• pp.88-96
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• 1995

Seismic design provisions in Korea has developed based on seismic provisions in United States (e.g., ATC 3-06). Current seismic design provisions in U .S. is moving toward adopting enhanced concept for design. Federal Emergence Management Agency (FEMA) Provides the NEHRP recommended Provisions for the Development of Seismic Regulations for New Buildings which can be used as a source document for use by any interested members of the building community. Current seismic design provisions in U .S. generally use a uni-level force. These provisions can not be satisfied if the limit state design is concerned. Limit state can be defined as a state causing undesirable performance o( a structure (e .g., serviceability, ultimate, buckling, etc.). Even if there are provision for controlling drift by two levels, it is still difficult to satisfy limit states using uni-level force. Architectural Institute of Japan (AIJ) uses a hi-level forces Int seismic loadings which can satisfy serviceability and ultimate limit state. However, the seismic parameters used in AIJ guideline are basically determined by subjective manner of code committee member and professions. These parameters need to be determined based on target quantities (target reliability, target energy dissipation, target displacement, target stress level, etc.). This study develops the method to determine the sesmic design parameters based on a certain taget level. Reliability is used as a target level and load factors in ANSI/ASCE 7-88 are selected as design parameters to be determined.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.795-798
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• 2016

Transmission X-ray tubes based on carbon nanotube have attracted significant attention recently. In most of these tubes, tungsten is used as the target material. In this article, the well-known simulator Geant4 was used to obtain some of the tungsten target parameters. The optimal thickness for maximum production of usable X-rays when the target is exposed to electron beams of different energies was obtained. The linear variation of optimal thickness of the target for different electron energies was also obtained. The data obtained in this study can be used to design X-ray tubes. A beryllium window was considered for the X-ray tube. The X-ray energy spectra at the moment of production and after passing through the target and window for different electron energies in the 30-110 keV range were also obtained. The results obtained show that with a specific thickness, the target material itself can act as filter, which enables generation of X-rays with a limited energy.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2650-2659
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• 2022

The dense granular flow spallation target is a new target concept proposed for an Accelerator-Driven Sub-critical (ADS) system. In this paper, the beam-target configurations of a tungsten granular flow target for the ADS with a thermal power of 1 GW is explored. The beam profile options using different scanning methods are discussed. The critical geometry parameters are adjusted to investigate the performance of the granular target from the aspects of neutron efficiency, stability and temperature distribution in target medium. To figure out how the target under accident conditions would behave, different clogging conditions are induced in the simulation. The dynamic processes are analyzed and some important parameters such as abnormal temperature rise and beam cutoff time window are obtained. The response of the sub-critical reactor to a clogging accident is also investigated. It is indicated that the monitoring of the granular flow by the neutron detectors in the sub-critical core will be effective.

• Korean Journal of Food Science and Technology
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• v.23 no.1
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• pp.88-92
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• 1991

To analyze the effects of the system parameters on the target parameters, which include the amount of water evaporation, water solubility index(WSI) and water absorption index(WAI), test trials of fractional factorial design of the three process variables at three levels were carried out for corn grit with a laboratory twin-screw extruder with three different screw configurations. The system parameters collected from the trials, such as extrusion temperature, specific mechanical energy input(SME) and mean residence time(RT), were showed the ranges of $129{\sim}182^{\circ}C$, $67{\sim}163\;kwh/ton$ and $12{\sim}34\;sec$, respectively. Within these ranges of the system parameters, the target parameters were able to be quantified by using multiple regression equations. The correlation of results with the system parameters blocked by the screw configuration as dependent variables, yield correlation coefficients above 0.90, and the correlation using the system parameters obtained from whole experiment system as the dependent variables yield correlation coefficients around 0.80. The functional relationship, which can be quantified by second order polynomial regression equation with only two system parameters within necessary degree of accuracy, can he graped in three dimensional surface response and contour diagrams.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.1958-1960
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• 2001

In this paper, we propose the design methodology of target tracking system using the identification of TS fuzzy model based on genetic algorithm(GA) and RLS algorithm. In general, the objective of target tracking is to estimate the future trajectory of the target based on the past position of the target obtained from the sensor. In the conventional and mathematical nonlinear filtering method such as extended Kalman filter(EKF), the performance of the system may be deteriorated in highly nonlinear situation. In this paper, to resolve these problems of nonlinear filtering technique, the error of EKF by nonlinearity is compensated by identifying TS fuzzy model. In the proposed method, after composing training datum from the parameters of EKF, by identifying the premise and consequent parameters and the rule numbers of TS fuzzy model using GA, and by tuning finely the consequent parameters of TS fuzzy model using recursive least square(RLS) algorithm, the error of EKF is compensated. Finally, the proposed method is applied to three dimensional tracking problem, and the simulation results shows that the tracking performance is improved by the proposed method.

• ETRI Journal
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• v.36 no.5
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• pp.704-713
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• 2014

Most natural language processing tasks depend on the outputs of some other tasks. Thus, they involve other tasks as subtasks. The main problem of this type of pipelined model is that the optimality of the subtasks that are trained with their own data is not guaranteed in the final target task, since the subtasks are not optimized with respect to the target task. As a solution to this problem, this paper proposes a consolidation of subtasks for a target task ($CST^2$). In $CST^2$, all parameters of a target task and its subtasks are optimized to fulfill the objective of the target task. $CST^2$ finds such optimized parameters through a backpropagation algorithm. In experiments in which text chunking is a target task and part-of-speech tagging is its subtask, $CST^2$ outperforms a traditional pipelined text chunker. The experimental results prove the effectiveness of optimizing subtasks with respect to the target task.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.4 s.142
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• pp.299-306
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• 2005

To determine a guidance law which is suitable for Target Tracking System(TTS) of an underwater vehicle, the performance (hitting probability) of TTS were calculated with four different guidance schemes, considering underwater vehicle's manoeuvrability and characteristics of seeking equipment such as sonar To evaluate the performance of TTS with each guidance law, numerous target-tracking simulations of underwater vehicle were performed under the condition of target's various motion scenario. Furthermore, the effect of sonar characteristics to the performance of guidance law in TTS was studied by changing parameters of sonar such as frequency of ping and detecting error of target. The pursuit-tail guidance law showed the best performance among four different guidance laws. Complex motion of target from straight line to turning circle and zigzag movement, low frequency of sonar ping and large detecting error of target decreased the hitting probability.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3164-3170
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• 2021

The increasing interest that GEANT4 is gaining nowadays, because of its special capabilities, prompted us to address its reliability in neutronic calculation for the realistic and complex spallation target MEGAPIE of the Paul Scherrer Institute of Switzerland. In this paper we have specifically addressed the neutronic characterization of the active zone of this target. Three physical quantities are evaluated: neutron flux spectra and total neutron fluxes on target's z-axis, and the neutron yield as a function of the target's altitude and radius. Comparison of the obtained results with those of the MCNPX reference code and some experimental measurements have confirmed the impact of the geometrical and proton beam models on the neutron fluxes. It has also allowed to reveal the intrinsic influence of the code type. The resulting differences reach a factor of ~2 for the beam model and 4-18% for the other parameters cumulated. The analysis of the neutron yield has led us to conclude that: 1) Increasing the productivity of the MEGAPIE target cannot be achieved simply by increasing the thickness of the target, if the irradiation parameters are not modified. 2) The size of the spallation area needs to be redefined more precisely.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.299-309
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• 2013

A comprehensive SAR(Synthetic Aperture Radar) simulation is considered to be a complicated task since a full knowledge of the signal propagation characteristics, antenna pattern, system internal errors and interference noises should be taken into account. In high resolution target application modes, the time varying nature of target RCS(Radar Cross Section) strongly affects the generated SAR images. In this paper, in-depth SAR simulations are performed and analyzed incorporating the STK tools and MATLAB software. STK provides realistic orbit parameters while its radar module helps to extract accurate radiometric parameters of ground targets. SAR raw data corresponding to a given target is generated and processed using MATLAB simulator. The performance is measured by PSLR(Peak Sidelobe Ratio) and ISLR(Integrated Sidelobe Ratio) for a point target, which can be used as reference parameters for accurate radiometric calibration. Finally, high resolution target simulations are performed by adopting time varying target RCS characteristics.

• Korean Journal of Remote Sensing
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• v.28 no.4
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• pp.369-392
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• 2012

Recently, many target detection algorithms were developed for hyperspectral image. However, almost of these studies focused only accuracy from 1 or 2 data sets to validate and compare the algorithms although they give limited information to users. This study aimed to compare usability of target detection algorithms with various parameters. Five parameters were proposed to compare sensitivity in aspect of detection accuracy which are related with radiometric and spectral characteristics of target, background and image. Six target detection algorithms were compared in aspect of accuracy and efficiency (processing time) by variation of the parameters and image size, respectively. The results shown different usability of each algorithm by each parameter in aspect of accuracy. Second order statistics based algorithms needed relatively long processing time. Integrated usabilities of accuracy and efficiency were various by characteristics of target, background and image. Consequently, users would consider appropriate target detection algorithms by characteristics of data and purpose of detection.