• Journal of Power Electronics
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• v.11 no.6
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• pp.870-879
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• 2011

Regulated peak power tracking (RPPT) systems such as the series structure and the series-parallel structures are commonly used in satellite space power systems. However, these structures process the solar array power or the battery power to the load through two cascaded regulators during one orbit cycle, which reduces the energy transfer efficiency. Also the battery charging time is increased due to placement of converter between the battery and the solar array. In this paper a parallel structure has been proposed which can improve the energy transfer efficiency and the battery charging time for satellite space power RPPT systems. An analogue controller is used to control all of the required functions, such as load voltage regulation and solar array stabilization with maximum power point tracking (MPPT). In order to compare the system efficiency and the battery charging efficiency of the proposed structure with those of a series (conventional) structure and a simplified series-parallel structure, simulations are performed and the results are analyzed using a loss analysis model. The proposed structure charges the battery more quickly when compared to the other two structures. Also the efficiency of the proposed structure has been improved under different modes of solar array operation when compared with the other two structures. To verify the system, experiments are carried out under different modes of solar array operation, including PPT charge, battery discharge, and eclipse and trickle charge.

• Spatial Information Research
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• v.7 no.2
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• pp.209-221
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• 1999

In this research, AVL-GIS(Automatic Vehicle Location System linked with Geographic Information System) system was developed using integration of core techniques of GIS engine written by Java language, GOS(Global Positioning System) and wireless telecommunication interfacing techniques. IDGPS(Inverted differential GPS) techniques was employed to estimate accurate position of mobile vehicle and to supervise their path from AVL-GLS control center system. Between mobile vehicle and AVL-GLS control center system which has spatial data analysis function, road network and rleate ddata base were connected wireless phone to communicate for position an dmessage in real time. The developed system from this research has more enhanced GIS functions rather than previous AVL oriented system which has MDT for message display and voice communication only. This system can support build-up application system such as fleet management like bus, taxi, truck, disaster and emergency and monitoring of transportation status for customer s order via web browser in filed of EC/CALS in low cost.

• Journal of the Korean Society for Railway
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• v.14 no.4
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• pp.383-389
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• 2011

Until now, in planning and constructing KTX and the Express Way, the connectivity and transfer between these facilities have not been considered. In this study the effect of mode choice behavior by connecting KTX and the Express Way is analyzed through estimating Multinomial Logit Model and Binary Logit Model. The SP and RP surveys to develop these models were carried out and the data were selected from the passengers using the KTX station, Express Bus Terminals and Rest Areas in the Express Way. To test the effect of connectivity and transfer in the field, the case study for Dongtan KTX station was carried out. According to the results, connecting the KTX station and the Express Way has the effect of increasing the demand by 30%. And this is caused by saving about 120 minutes of traveling time from Seoul to Pusan. This study shows that the connectivity and transfer can increase the efficiency of transportation system and the improvement in the mobility and accessibility will maximize the usages of these two facilities.

• Journal of the Korean Society for Railway
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• v.18 no.1
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• pp.25-32
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• 2015

It has been subject to question whether a conventional traffic signal controller can support efficient operation at grade intersections in which vehicles and tram lines cross concurrently. This study proposes a list of functional requirements for a traffic signal controller to support effective operation of trams at such an intersection. The considered details includes the combinations of geometric conditions at which vehicle, bus, and tram lines are aligned, the types of exclusive tram signals, and the combinations of various signal phases, including exclusive tram phases, which are currently undefined in the nation. The results suggest that the controller should be capable of dealing with the NEMA standard overlap relays and a quadruple-ring phase representation scheme.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.7
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• pp.103-110
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• 2014

Recent TSV based 3D Integrated Circuit (IC) technology needs more powerful thermal management techniques. However, because cooling cost and form factor are restricted, thermal management are emphasis on software based techniques. But in case of throttling thermal management which one of the most candidate technique, increasing bus occupation induce total performance decrease. To solve communication bottleneck issue in TSV based 3D SoC, we proposed adaptive throttling technique Experimental results show that the proposed method can improve throughput by about 72% compare with minimal path routing.

• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.55-65
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• 2009

Due to the rapid increase of electricity demand, consideration of environmental constraints in optimal power flow (OPF) problems is increasingly important. In Algeria, up to 90% of electricity is produced by thermal generators (vapor, gas). In order to keep the emission of gaseous pollutants like sulfur dioxide (SO2) and Nitrogen (NO2) under the admissible ecological limits, many conventional and global optimization methods have been proposed to study the trade-off relation between fuel cost and emissions. This paper presents an efficient decomposed Parallel GA to solve the multi-objective environmental/economic dispatch problem. At the decomposed stage the length of the original chromosome is reduced successively and adapted to the topology of the new partition. Two subproblems are proposed: the first subproblem is related to the active power planning to minimize the total fuel cost, and the second subproblem is a reactive power planning design based in practical rules to make fine corrections to the voltage deviation and reactive power violation using a specified number of shunt dynamic compensators named Static Var Compensators (SVC). To validate the robustness of the proposed approach, the algorithm proposed was tested on the Algerian 59-bus network test and compared with conventional methods and with global optimization methods (GA, FGA, and ACO). The results show that the approach proposed can converge to the near solution and obtain a competitive solution at a critical situation and within a reasonable time.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.3
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• pp.167-176
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• 1995

The purpose of this study is to suggest objective basic data for park management proposal through the quantitative analysis of users' behaviors and satisfaction for the actual conditions of management in Moaksan provincial park. For this, users' behaviors and socio-ecnomic characteristics have been analyzed. Specifically, it attempts to investigate users' anticipation and degree of satisfaction applied Expectancy Theory by Likert scale. And users' satisfaction for the actual conditions of management had been analyzed by using the multiple regression. Results of this study can be summarized as follows ; From the aspect of utilization reality, the male usage was silighty higher than female usage, and the usage rate reality, the male usage was slighty higher than female usage, and the usage rate among the young and students such as university students also appeared slightly higher than the norm. Due to the fact, subject park had been provincial park, bus usage was predominant, and users' visit park 1 or 2 times a year. Generally, the value of users' post occupancy evaluation were higher than those of anticipated, and Use in night and facilities were lower. A sense of the season, dense of forest, beauty of skyline and a perspective view appeared as main explicatory variables having positive effects on the satisfaction level for the landscape. Amount of plant and shade were positive variables on the satisfaction and users' had dissatisfaction with trial damage. According to the multiple regression analysis, the major variables to the satisfaction for the actual condition of vegetation management were diversity, recovery of artificial injury.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.10
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• pp.586-594
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• 2003

X-Match algorithm is a lossless compression algorithm suitable for hardware implementation owing to its simplicity. It can compress 32 bits per clock cycle and is suitable for real time compression. However, as the bus width increases 64-bit, the compression unit also need to increase. This paper proposes the cooperative parallel X-Match (X-MatchCP) algorithm, which improves the compression speed by performing the two X-Match algorithms in parallel. It searches the all dictionary for two words, combines the compression codes of two words generated by parallel X-Match compression and outputs the combined code while the previous parallel X-Match algorithm searches an individual dictionary. The compression ratio in X-MatchCP is almost the same as in X-Match. X-MatchCP algorithm is described and simulated by Verilog hardware description language.

• The KIPS Transactions:PartD
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• v.17D no.1
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• pp.41-52
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• 2010

A relation between generated test cases and an original requirement is important, but it becomes very complex because a relation between requirement models and requirements are m-to-n in automatic test case generation based on models. In this paper, I suggest automatic generation technique for REED (REquirement EDitor), 1-to-1 requirement modeling tool. Test cases are generated though 3 steps, Coverage Target Generation, IORT (Input Output Relation Tree)Generation, and Test Cases Generation. All these steps are running automatically. The generated test cases can be generated from a single requirement. As a result of applying to three real commercial systems, there are 5566 test cases for the Temperature Controller, 3757 test cases for Bus Card Terminal, and 4611 test cases for Excavator Controller.

• Journal of Astronomy and Space Sciences
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• v.33 no.4
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• pp.323-333
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• 2016

In this study, the uncertainty requirements for orbit, attitude, and burn performance were estimated and analyzed for the execution of the $1^{st}$ lunar orbit insertion (LOI) maneuver of the Korea Pathfinder Lunar Orbiter (KPLO) mission. During the early design phase of the system, associate analysis is an essential design factor as the $1^{st}$ LOI maneuver is the largest burn that utilizes the onboard propulsion system; the success of the lunar capture is directly affected by the performance achieved. For the analysis, the spacecraft is assumed to have already approached the periselene with a hyperbolic arrival trajectory around the moon. In addition, diverse arrival conditions and mission constraints were considered, such as varying periselene approach velocity, altitude, and orbital period of the capture orbit after execution of the $1^{st}$ LOI maneuver. The current analysis assumed an impulsive LOI maneuver, and two-body equations of motion were adapted to simplify the problem for a preliminary analysis. Monte Carlo simulations were performed for the statistical analysis to analyze diverse uncertainties that might arise at the moment when the maneuver is executed. As a result, three major requirements were analyzed and estimated for the early design phase. First, the minimum requirements were estimated for the burn performance to be captured around the moon. Second, the requirements for orbit, attitude, and maneuver burn performances were simultaneously estimated and analyzed to maintain the $1^{st}$ elliptical orbit achieved around the moon within the specified orbital period. Finally, the dispersion requirements on the B-plane aiming at target points to meet the target insertion goal were analyzed and can be utilized as reference target guidelines for a mid-course correction (MCC) maneuver during the transfer. More detailed system requirements for the KPLO mission, particularly for the spacecraft bus itself and for the flight dynamics subsystem at the ground control center, are expected to be prepared and established based on the current results, including a contingency trajectory design plan.