• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.1
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• pp.206-213
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• 1996

Third order correlation funciton is to be advantageous to detect unique features embedded in various random signals that are undetectable with second order correlation or power spectrum. In this paper, we will introduce optical modulator which consists of a laser light source, 2-dimensional ultrasonic diffractor cell with signal controlling circuitry, and a CCD camera connected to personal computer for image processing. With this modulator, the third order correlaiton pattern of signal can be immediately obtained at the camera due to parallel nature of optical computing.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.166-168
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• 2006

새로운 도시교통 시스템을 개발하기 위하여 시스템의 적용지역 검토 후 운영자, 이용자, 공급자 측면에서의 요구사항 도출과 아울러 이를 토대로 하여 시스템 요구사항을 도출하였다. 이는 기능 및 성능으로 구분할 수 있고 하부시스템별로 기능과 성능을 할당하여 각 하부시스템의 기능과 주요 장치가 갖추어야 할 조건, 용량 등을 정의하였다. 또한 환경요구사항 및 하부 시스템별 기기의 동작 조건등을 정의하여 시스템 개념을 확립하였다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.2
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• pp.119-132
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• 1990

To design protection coordination for an electric power distribution system, an expert system is developed, using both the veteran expert's heuristics and the guide book for the distribution facility operation considering feeder configuration, service route, load characteristics fault current and load current. The expert system developed in this papaer determines the type of protective device(clearing current and sequence). The location and rating change of protective device in the old feeder is realized by using old database. Current(T-C) curves of various kinds of protective devices are stored in Knowledge Base (KB). The expert system is developed on a 32 bit personal computer using PROLOG, AutoCAD,dBASEIIIPLUS and FORTRAN. To compute the fault current and loadflow, FORTRAN is used.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2011.06a
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• pp.230-236
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• 2011

Despite economic sanctions, including Western countries' ban on exports of advanced technology, North Korea is regarded as being equipped with independent technology power in the science technology sector as shown in its launch of intercontinental ballistic missile. However, North Korea has been shrouded in mystery in terms of software technology level. Chosun Computer Center, a software development institution representing North Korea since 2006, mobilized IT experts from Kim Il-sung University and Kim Chaek University of Technology and launched a project for an independent development of a computer operating system (OS), called "Red Star." Recently, it made public the 2.1-version. The OS program, which was manufactured in two types for a server computer and personal computer and are being supplied to institutions and individuals.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.623-624
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• 2006

Over the past decade, changes in product development processes and increased consumer demands have dramatically influenced engineering working practices and targets. The information technology revolution has made its appearance concurrent to this relentless escalation in product engineering requirement. It has offered hopes for improved productivity despite these increasing demands. The wide availability of personal computing power, virtually inexhaustible sources of information and an abundance of computerized engineering tools have created great expectations. CAPP (Computer Aided Process Planning) Expert system and database were developed using VB.NET and Microsoft SQL 2000 Server.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1374-1389
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• 1994

In this paper, a novel M-ary orthogonal CDMA scheme which utilizes time hopping codes and binary orthogonal sequences is proposed for personal communication system. Its modulated output signal has the characteristics of greater bandwidth occupancy and lower spectral density level as well. So this scheme is useful for spectrum overlay with existing narrowband communication systems which occupy current radio frequency channels. This paper investigates system characteristics through the analysis of modulated output signal power spectrum, and demonstrates the possibility of spectrum overlay.

• Journal of the Korean Society of School Health
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• v.28 no.2
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• pp.120-126
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• 2015

Purpose: The purpose of this study was to understand interpersonal dispositions and social support among high school students and identify factors associated with depression. Methods: A total of 604 students (320 males and 284 females) from four high schools conveniently sampled from high schools in the Incheon area participated in a self-administered survey. Results: According to hierarchical multiple regression analysis, the following factors significantly affected the participants' depression levels with the explanatory power of 30.6%: grade, perceived health status, sympathetic-acceptable personality, sociable-friendly personality, rebellious-distrustful personality, parent support, peer support, and the support from community. Conclusion: In this study, interpersonal dispositions and social support were positively associated with depression. These results suggest that strengthening personal relations and social support can help high school students in terms of mental health and suicide prevention.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3079-3089
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• 2015

In this paper, a smart constrained application protocol (CoAP)-based gateway with a border router is proposed for home safety services to remotely monitor the trespass, fire, and indoor air quality. The smart CoAP gateway controls a home safety sensor node with a pyroelectric infrared motion sensor, a fire sensor, a humidity and temperature sensor, and a non-dispersive infrared CO2 sensor and gathers sensing data from them. In addition, it can convert physical sensing data into understandable information and perform packet conversion as a border router for seamless connection between a low-power wireless personal area network (6LoWPAN) and the Internet (IPv6). Implementation and laboratory test results verify the feasibility of the smart CoAP gateway which especially can provide about 97.20% data throughput.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.616-620
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• 2006

IEEE 802.15.4 is designed for low-rate wireless personal area networks (LR_WPAN) and it attempts to provide a low data rate, low power, low cost wireless networking on the device-level communication. In this paper, I have established a realistic environment for the effect of collision in nonbeacon-enabled mode and beacon enabled mode. The data throughput and delivery ratio are investigated as the performance metrics.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1733-1751
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• 2015

The IEEE 802.15.4 standard not only provides a maximum of seven guaranteed time slots (GTSs) for allocation within a superframe to support time-critical traffic, but also achieves ultralow complexity, cost, and power in low-rate and short-distance wireless personal area networks (WPANs). Real-time wireless body area sensor networks (WBASNs), as a special purpose WPAN, can perfectly use the IEEE 802. 15. 4 standard for its wireless connection. In this paper, we propose an adaptive GTS allocation scheme for real-time WBASN data transmissions with different priorities in consideration of low latency, fairness, and bandwidth utilization. The proposed GTS allocation scheme combines a weight-based priority assignment algorithm with an innovative starvation avoidance scheme. Simulation results show that the proposed method significantly outperforms the existing GTS implementation for the traditional IEEE 802.15.4 in terms of average delay, contention free period bandwidth utilization, and fairness.