• Journal of Power Electronics
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• 제9권2호
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• pp.198-206
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• 2009

An algorithm is developed that enables a single-phase matrix converter (SPMC) to perform functions of a generalized single phase power electronics converter such as acting as a frequency changer, rectifier, inverter, and chopper. This reduces the need for new converter hardware. The algorithm is implemented first on computer simulation software Orcad Capture CIS version 9.1. Simulation results are presented for five types of converters with a control input variable that decides the 1) type of converter and 2) type of output waveform. The simulated results verify the working and operation of a generalized converter based on SPMC. Simulated results are verified with experimental results. Hardware design is obtained using readily available ICs and other components. The trigger circuit has been tested qualitatively by observing waveforms on CRO. The operation of the proposed system has been found to be satisfactory.

• Journal of electromagnetic engineering and science
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• 제2권2호
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• pp.93-99
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• 2002

The Cartesian loop chip which is one of key devices in narrow-band Walky-Talky transmitter using RZ-SSB modulation method was designed and implemented with 0.35 Um CMOS technology. The reduced size and low cost of transmitter were available by the use of direct-conversion and Cartesian loop chip, which improved the power efficiency and linearity of transmitting path. In addition, low power operation was possible through CMOS technology. The performance test results of transmitter showed -23 dBc improvement of IMD level and -30 dEc below suppression of SSB characteristic in the operation of Cartesian loop chip (closed-loop). At that time, the transmitting power was about 37 dBm (5 W). The main parameters to improve the transmitting characteristic and to compensate the distortion in feed back loop such as DC-offset, loop gain and phase value are interfaced with notebook PC to be controlled with S/W.

• 한국컴퓨터정보학회논문지
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• 제7권2호
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• pp.19-33
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• 2002

본 연구에서는 Parwan CPU를 VHDL을 이용하여 Behavioral Leve에서 기술하고 Dataflow LEVEL에서 상호 연결하여 기술하였고, Test-bench 방식을 이용하여 프로세서의 동작을 확인하기 위해 시뮬레이션 하였다. 제시된 방식은 설계의 정보교환이 용이하고 동작의 표현이 정확하고 간결하였으며, 설계의 문서화가 용이하며, 구성된 프로세서의 동작을 확인하기가 용이하였다. VHD교의 Behavioral 기술은 설계자에게 설계된 시스템을 확인할 때 많은 도움을 주었으며. Dataflow 기술은 설계의 버스연결과 레지스터 구조를 확인할 때 유용하게 사용할 수 있었다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.81-86
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• 1999

A Web-based information system from the Korea Agricultural Water Use Laboratory AWUL, has been developed to provide with regional water management information and guidance for the operations of irrigation reservoirs through the World Wide Web(WWW). Twenty-six reservoirs are selected as the reference reservoirs for regional water management , and the real-time operation guide may be issued the grwoing seasons. The information available from the system includes the wether forecasting , drought analyses, and reservoir operation data for those reference sites. For a specific reservoir, the manager may access the system to obtain the water requriement, irrigation secheduling , and reservoir operations that fit best to the irrigation district.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2003년도 춘계학술대회논문집
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• pp.115-119
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• 2003

It requires a great deal of efforts to maintain a distributed system. What is important here is that we should be able to upgrade/maintain a distributed system without stopping the system in operation. For this, what we need is a dynamic reconfigurable framework for highly available distributed systems. In this paper, we propose objects-hot-swapping methods as a solution to our problem. These methods permit us to dynamically upgrade/expand a system without stopping the system in operation. In addition, we analyze these methods and show that an approach based on proxy is the most efficient. Furthermore, we propose two proxy-based approaches: the first one based on the static proxy provides for a fast execution time but it is difficult to implement. The second one based on the dynamic proxy provides for a slow execution time but it is easier to implement. Finally, we propose a hot swapping framework for these static and dynamic proxy.

• 한국안전학회지
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• 제22권3호
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• pp.88-97
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• 2007

A point based speed enforcement system(SES) has been widely used in roadways to reduce the operating speeds and potential traffic accidents. Recently, the needs for introudcing new SES using point-to-point speed measurement was presented, however, no practical guidelines or justification of the system was available. This study investigated the effectiveness of the current SES and introduction of the new SES through user interview survey method. Survey results showed that 33% of respondents were unsatisfactory to the current way of SES operation, which was 11% higher than satisfactory respondents, and about 70% of the respondents supported the introduction of point-to-point based SES operation. A majority of respondents preferred the straight roadway segment, bridge and tunnel, and curved roadway segment for a start application site with the segment length of 1-5 km long. Using these survey results, an introduction scheme was discussed in terms of legal bases, installation criteria, and operational guidelines.

• 한국전기전자재료학회논문지
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• 제16권9호
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• pp.771-774
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• 2003

In this paper, the programming characteristics of the multi-bit devices based on SONOS structure are investigated. Our devices have been fabricated by 0.35 $\mu\textrm{m}$ complementary metal-oxide-semiconductor (CMOS) process with LOCOS isolation. In order to achieve the multi-bit operation per cell, charges must be locally frapped in the nitride layer above the channel near the source-drain junction. Programming method is selected by Channel Hot Electron (CUE) injection which is available for localized trap in nitride film. To demonstrate CHE injection, substrate current (Isub) and one-shot programming curve are investigated. The multi-bit operation which stores two-bit per cell is investigated. Also, Hot Hole(HH) injection for fast erasing is used. The fabricated SONOS devices have ultra-thinner gate dielectrics and then have lower programming voltage, simpler process and better scalability compared to any other multi-bit storage Flash memory. Our programming characteristics are shown to be the most promising for the multi-bit flash memory.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2611-2613
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• 2000

This paper deals with a novel approach to unknown inputs observer(UIO) design for linear time-invariant dynamical systems using a fast Walsh transform and Walsh function's differential operation. Generally, UIO has a derivation of system outputs which is not available from the measurement directly. And it is an obstacle to estimate the unknown inputs properly when unexpected measurement noises are presented. Therefore, this paper propose an algebraic approach to eliminate such problems by using a Walsh function's differential operation.

• 대한안전경영과학회지
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• 제8권3호
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• pp.103-114
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• 2006

A cross docking operation involves multiple trucks (known as inbound trucks) that deliver items from suppliers to a distribution center and multiple trucks (known as outbound trucks) that ship items from the distribution center to customers. Based on customer demands, an inbound truck may have its items transferred to multiple outbound trucks. Similarly, an outbound truck can receive its consignments from multiple inbound trucks. A unique characteristic of a cross docking system is the absence or prohibition of long term storage of items at the distribution center. Items delivered to the distribution center from suppliers are shipped to customers as soon as possible without being placed in storage in the distribution center. The objective of this paper is to develop the optimal operational strategy for finding the best truck docking sequence for both inbound and outbound trucks in order to minimize total operation time where a temporary storage area is not available in a cross docking system.

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.698-703
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• 2016

We report a new all-optical flip-flop (AOFF) with a quite simple structure, using optical beating in an injection-locked Fabry-Perot laser diode (FP-LD) with optical bistability. While conventional AOFF methods using an injection-locked FP-LD require additional devices such as secondary FP-LDs or polarization controllers for reset operation, the proposed method can be implemented using only a single commercially available FP-LD with set and reset signals. The optical beating induces intensity fluctuations inside the FP-LD, and releases the locking state to the reset state. Even though we demonstrated the AOFF at 100 Mbit/s, we expect that its operation rate could extend to 10 Gbit/s, according to the limit of the FP-LD's frequency response.