• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.4
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• pp.407-418
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• 2014

As the high-throughput requirement in the next generation communication system increases, it becomes essential to implement high-throughput SISO (Soft-Input Soft-Output) decoder with minimal hardware resources. In this paper, we present the comparison results between cascaded radix-4 ACS (Add-Compare-Select) and LUT (Look-Up Table)-based radix-4 ACS in terms of delay, area, and power consumption. The hardware overhead incurred from the retiming technique used for high speed radix-4 ACS operation is also analyzed. According to the various analysis results, high-throughput radix-4 SISO decoding architecture based on simple path metric recovery circuit is proposed to minimize the hardware resources. The proposed architecture is implemented in 65 nm CMOS process and memory requirement and power consumption can be reduced up to 78% and 32%, respectively, while achieving high-throughput requirement.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.134-135
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• 2018

Nuclear Power Plant consists of about 1.4 million facilities. and the design standards and design requirements for the continuos utilization and safety of facilities are complexly connected with the facilities. When a design change for facilities or design requirements is occurred at the time of construction or operation, there are a lot of facilities, design requirements, and design bases that are affected by the facilities or design bases being changed. The above design changes are so complex that the existing document-bases design change process is time-consuming and may also cause human error. In this study, we developed a design requirement taxonomy that can be applied to the data-centric design bases document that can improve it. To do this, we analyze the design elements from the highest level to the lowest level applied to the nuclear power plant, and classify the design elements according to the characteristics of the design elements.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.157-161
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• 2004

Urban transit is system that offer target Performance and function because various lower part system such as vehicles, signaling, power supply, rail track is consisted as complex. It is important first of all that describe correctly system requirement until configuration of system, design, manufacture, installation and test verification so that the complicated urban transit system is to act safety and reliable and to display target Performance and function properly. The system requirement assist the system developer to comprehensive the performance and function of system in basic design. Therefore, In this paper wishes to study way to analyze system of system requirement and apply to Urban transit.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.7
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• pp.1161-1168
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• 2016

Battery energy storage system(BESS) attract the attention of the power system operators with its fast response to a disturbance in spite of its limited energy capacity. This paper proposes the operating method of BESS for following the Automatic Generation Control(AGC) frequency control which is centrally distributed by a system operator. As BESS needs to just meet the control requirement from the system operator, it should be able to properly manage the state of charge(SOC) of BESS to be available to control signal. For doing these, the proposed method distributes the control requirement to available batteries in proportion to its SOC. In addition, unavailable batteries are controlled to recover the SOC to an appropriate range, and the recovering power is supplied by available batteries meeting the control requirement. Moreover, the proposed method manages the efficiency of power conversion system (PCS) by limiting the number of PCS to be assigned for the low control requirement. Finally, the case studies are carried out to verify the effectiveness of proposed strategy.

• Journal of Biosystems Engineering
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• v.6 no.1
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• pp.1-14
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• 1981

A laboratory model test was carried out with a newly designed model to figure out the vibration characteristics of the vibratory tillage tool according to the method of forced vibration, i.e., horizontally and vertically forced vibrations. The results are summarized as follows: 1. The reduction ratios of the draft force of the vibratory blade were 14.2-42.6% for the case where the vibration was forced parallel to the travelling direction of the blade, and 15-54.5% for the vertically forced vibration. And it was thought that the method of vertically forced vibration was preferable to the reduction of the draft force. 2. The ratio of the draft force of a vibratory blade to that of a static one could be represented as a function of V/At. It was found to be possible to reduce the draft force by taking a lower value of (V/Af) and this meant that the effictiveness of tillage practice using the vibratory system would be limited. 3. The torque to the main rotating shaft to vibrate the model blade increased frequency and amplitude. This tendency varied according to the physical properties of tested soil. In case of horizontally forced vibration, the torque was 8~34% less than in case of vertically forced vibration. 4. With the increase of frequency, the total power requirement increased linearly, and also the portion of oscillating power requirement in the total power tended to increase. The magnitude of the total power requirement was 1.4-13 times greater than that of a static one for the case of horizontal vibration, and 1.5-15 times greater for the case of vertical vibration. It was thought that the horizontal vibration of the blade was preferable to the vertical vibration in view of the power requirement. 5. A linearity was found between the amplitude of moment oscillogram and magnitude of oscillating acceleration. Only positive values of moment occurred when the blade was forced to vibrate vertically, but negative values occurred in rarity in the case of amplitude A3 when the blade was forced to vibrate horizontally.

• Journal of Biosystems Engineering
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• v.9 no.2
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• pp.1-7
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• 1984

The engines mounted on power-tillers are used as power source in various kinds of works such as plowing, harrowing, transporting, spraying, water pumping and threshing, etc. But the engines have not been used effectively from a standpoint of fuel consumption because of lack of proper power transmission system and lack of understanding of fuel consumption characteristics of the engines. Therefore, this study was attempted to establish proper power transmission system between the power-tiller engines and various implements. In order to accomplish the above objective, firstly, power requirement and pulley sizes for various implements, which are driven by the power-tiller engines, were investigated to find out whether the power transmission system is proper. Secondly, partload variable engine-speed test was conducted for 3 different sizes of diesel engines to measure to specific fuel consumption. Thirdly, the present power transmission systems were analyzed in terms of specific fuel consumption, and proper power transmission systems were suggested for various implements. The results of this study are summarized as follows: 1. Power requirement for each fixed-type implement of power-tiller varied from 1.5 ps to 11 ps according to its type and operating conditions, but generally in the range of 2.5 ps to 7 ps. 2. Each power tiller and implement were equipped with only one size of pully with few exeptions. With the present power transmission systems, the engines can't be utilized effectively in terms of fuel economy. The pulley size of engine or implement should be diversified to provide the optimum engine speed for different implements. 3. For a diesel eninge with the rated power output of 6 ps, the optimum engine speed to minimize specific fuel consumption was 2200 rpm for the power reguirement in the range of 6 ps or more, 1700 rpm in the range of 4 to 6 ps, and 1200 rpm in the range of 4 ps or less. 4. For a diesel engine with the rated power output of 8 ps, the optimum engine speed was 2200 rpm for the power requirement in the range of 7 ps or more, 1700 rpm in the range of 4.8 to 7 ps, and 1200 rpm in the range of 4.8 ps or less. 5. For a diesel engine with the rated power output of 10 ps, the optimum engine speed was 2200 rpm for the power requirement in the range of 8.4 ps or more, 1700 rpm in the range of 5.4 ps to 8.4 ps, and 1200 rpm in thr range of 5.4 ps or less. 6. Provided the existing implements are dirven by 8 ps diesel engines, the optimum size of engine pulley should be larger than 120mm for the works of requiring less than 4 ps and 90-110mm for the works requiring 4.5-6.5 ps in order to minimize fuel consumption.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.12
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• pp.715-726
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• 1999

This paper estimates the capacity of shunt type active power filters(APF) for harmonic/reactive power compensation with a thyristor converter load. The base capacity requirement of APF is defined for idealized converter load current waveform and the effect of commutation overlap on the APF capacity is examined. The APF capacity required for reactive power compensation in addition to the harmonic elimination is estimated to give maximum achievable power factor for various operating condition of the partially-loaded thyristor converter. The method of current limit of APF is introduced, and it is shown that the APF capacity can be considerably reduced by deliberately limiting the peak current while maintaining the filtering performance to meet the level std 519 regulation.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.488-490
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• 2006

In the electric power industry, It is important that the supply of energy must always be guaranteed. To satisfy these requirements, various forms of technologies are needed, such as RFID tag, reader, sensor network, middleware and so on. WSN (Wireless Sensor Network) technologies of the electric power industry are in the early stage and there is no clear guideline for developing electric facility management system using WSN. Relevant experience is limited, the challenge will be to derive requirement from business practice and to determine whether it is possible or not. To explore this issue, we focus on researching and field test of prototype system in Korea Electric Power Corporation (KEPCO). In this paper we describe requirement from power industry. And we introduce design and implementation of the power facility monitoring system.

• Journal of Applied Reliability
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• v.15 no.3
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• pp.145-148
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• 2015

The products to meet the requirement of are installed in nuclear power plant and the reliability target should be provided in the requirement. However, it is not easy to set a reliability target using quantitative analysis. The objective of this paper is to propose a method of reliability target setting considered warranty cost for process controller and then compare a reliability target with reliability analysis result.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.401-408
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• 2016

During daylight, the solar array of low earth orbit satellites harvests electrical power to operate satellites. The power conversion of the solar array is carried out by control of the operation point using the solar array regulator when the solar array faces the sunlight. Thus, the design of the solar array should comply with not only the power requirement of satellite system but also the input voltage requirement of the solar array regulator. In this paper, the design requirements of the solar array for low earth orbit satellites are defined, and the means of satisfying these requirements are described. In addition, the architecture of a multi-distributed interface is suggested to maximize the power harvested from a solar array having high temperature deviation between each panel. The power analysis in this paper shows the optimal number of multi-distributed interfaces with a converter.