• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.442-446
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• 2004

KOMPSAT series use software-controlled unregulated bus system in which the main bus is directly connected to a battery and the duty-ratio for PWM switch is controlled by the on-board satellite software. This paper proposes a new power-stage circuit that can be available for modularization of the power regulator which is used at the software-controlled unregulated bus system satellite. And we analyze the proposed power-stage operation according to its operating modes and verify it by performing software simulation and hardware experiment using prototype. We constructs a parallel-module converter which is composed of proposed power-stages and perform experiment to verify modular characteristics of the proposed power-stage. Finally, we verify the usefulness of the proposed power-stage by comparing above results with those of a parallel-module converter made of conventional power-stages.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.2120-2132
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• 1997

A layout automation system for analog integrated circuits is proposed. The implemented system performs full-custom analog layout under the analog layout constraints. In order to overcome the demerits of conventional analog layout systems, parameterized module library is proposed. The system can support complex analog layout modules, resulting in a maximum expandability of the system. Moreover, modified dynamic multi-path algorithm is developed by enhancing the conventional Dijkstra algorithm. Several benchmark circuits such as comparator, op amp, and filter was tested by the system. Layout results compared to OPASYN show well-merging layout and interdigitized layout module.

• Annual Conference of KIPS
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• 2002.11a
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• pp.27-30
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• 2002

Recently, there are lots of concerning on the control of multi-agent control system and mixed reality integrating real and virtual environments. In this paper, an integrated agent control system based on mixed reality and mobile environment is proposed. The system consists of a manager, agents, a mapping module, a geographic information module, a WAP server, and a mobile manager. The manager has Hybrid Device Manager(HDM) working for revising images and position data of the agents to display that at the 3D virtual and mobile environments respectively. Especially, the images of the agent is translated to LBM format and displayed on the mobile phone, and the current position of the agent is displayed on the display screen, so that a user are able to control the agent when he is moving. Experimental results shows the proposed system lets us control the agents conveniently at a computer and a mobile phone.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.465-470
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• 2002

A novel phased array antenna system for space-borne polarimetric SAR is proposed and completed in this paper.The antenna system assures polarimetric and multi-mode capability of SAR. It has broadband, high polarization isolation and high port to port isolation. The antenna system is composed of broadband polarimetric microstrip antenna, T/R modules and multifunction beam controller nit. The polarimetric microstrip antenna has more than 100MHz bandwidth at L-band with -30dB polarization isolation and high port to port isolation. The microstrip element and T/R module's structure and characteristics, the subarray's performances measuring results are presented in detail in this paper. A design scheme on beam controller of the phased array antenna is also proposed and completed, which is based on Digital Signal Processing (DSP) chip -TMS320F206. This beam controller unit has small size and high reliability compared with general beam controller. In addition, the multifunction beam controller unit can acquire and then send the T/R module's working states to detection system in real time.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.11
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• pp.938-941
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• 2012

LED is divided to multichannel in order not to exceed a certain voltage in aspects of electric standard. However, it's not possible to know in accordance with what channel SMPS controls the constant voltage and current. In order to solve this problem, it needs to detect the maximum LED String voltage which is applied to LED control circuit, and it is possible to minimize the voltage drop when a difference of LED string voltage occurs by each channel if LED is controlled by the maximum LED string voltage detected. In addition, it is also possible to maximize the efficiency of LED if change LED voltage by detecting the maximum voltage. Feasibility of this claim was verified through implementation of the circuit.

• Journal of the Korean Physical Society
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• v.73 no.12
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• pp.1904-1907
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• 2018

We designed a depth-encoding positron emission tomography (PET) detector by using a bottom and side readout method with a cross-arranged scintillator array. To evaluate the characteristics of the novel detector module, we used the DETECT2000 simulation tool to perform the optical photon transport in the crystal array. The detector module consists of an $M(column){\times}N(row)$ cross-arranged crystal array composed of M/3 sub-arrays consisting of $N{\times}3$ crystals. The second column of the sub-array is arranged perpendicular to the first and the third columns. The crystal is optically coupled to the crystals of the other columns; however, the surfaces between the crystals in the same column are treated as reflectors. A $6{\times}5$ crystal array consisting of two sub-arrays was considered for proof of concept. The two multi-pixel photon counter (MPPC) arrays are coupled to the bottom and one side of the crystal array, respectively. The x-y position is determined by the bottom MPPC array, and the side MPPC array gives depth information. All pixels in the x-y plane and the z direction were clearly distinguished.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.181-181
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• 2017

Low impact development (LID) practices has become important to mitigate the damage from natural disasters in urban areas. Thereby many hydrological simulation models can simulate the hydrological impact of LID practices. However, commonly used models are not able to provide specific information to most users such as where LIDs should be placed and what kind of LID should be designed. In this study, a decision support system which can be used with the EPA's SWMM was developed for the determination of LID types and locations of LID practices, named Water Management Prioritization Module (WMPM), was applied to a urbanized university campus. Eight sub-catchments were selected as feasible candidate areas for the planning of LID practices. Pre-designated infiltration trenches and permeable pavements were applied to each selected sub-catchments, followed by peak and total runoffs comparison between before/after planning of LIDs. Moreover, TOPSIS, one of a multi-criteria decision analysis method was used in the procedure of selecting target sub-catchment areas and final prioritization of LID types and locations. As a result, sub-catchments S4 with permeable pavements and S16 with infiltration trenches has shown the most decrease in total and peak runoffs, respectively. Therefore, WMPM was found to be effective in determining the best alternative among various scenarios generated and simulated.

• Journal of IKEEE
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• v.22 no.4
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• pp.1036-1043
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• 2018

This paper presented future power system protection technologies through the HW/SW integration platform with IEC 61850 and IEEE c37.238 standards. To determine the implementation performance of the integrated platform, an example of EVM (Evaluation Module) was constructed to satisfy the standards. The platform has been identified as a future power system integrated IED(Intelligent Electronic Device) HW/SW technology that meets the level of error required by the time sync standard and the level of delay required by protecting the power system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.585-586
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• 2019

Recently, the systems for managing the labs provide services that can be managed in real time by using various sensors based on IoT. The system collects sensor data and transmits it to the server, identifies the dangerous situation, and sends operation commands to the devices. These systems have a centralized structure that slows data processing when managing multiple laboratories. To solve this problem, this paper proposes a system that manages laboratories in distributed processing environment to identify and manage risk situations. The sensor module is used to control the laboratory and to automatically identify and respond to the dangerous situation.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2670-2689
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• 2022

STREAM - a lattice transport calculation code with method of characteristics for the purpose of light water reactor analysis - has been developed by the Computational Reactor Physics and Experiment laboratory (CORE) of the Ulsan National Institute of Science and Technology (UNIST). Recently, efforts have been taken to develop a photon module in STREAM to assess photon heating and the influence of gamma photon transport on power distributions, as only neutron transport was considered in previous STREAM versions. A multi-group photon library is produced for STREAM based on the ENDF/B-VII.1 library with the use of the library-processing code NJOY. The developed photon solver for the computation of 2D and 3D distributions of photon flux and energy deposition is based on the method of characteristics like the neutron solver. The photon library and photon module produced and implemented for STREAM are verified on VERA pin and assembly problems by comparison with the Monte Carlo code MCS - also developed at UNIST. A short analysis of the impact of photon transport during depletion and thermal hydraulics feedback is presented for a 2D core also from the VERA benchmark.