• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.210-213
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• 2002

This paper addresses the design and implementation of compensation of rain attenuation for Ka-band satellite communication system complied with DVB-RCS[2]. A structure of rain fade compensation scheme in the Ka-band satellite communication system is presented. Rain fade compensation scheme in this paper is mainly applied into return-link, which is the path through which user terminal transmit the data tn hub system providing a service. Symbol rate and code rate of channel code are used as variable transmission parameter for rain fade compensation. For estimation of channel environment, SNR of the user terminal which is measured by demodulator of hub system is used. Rain fade compensation scheme in the paper changes the symbol rate and/or code rate according to the measured SNR so that it can compensate the attenuation of the signal.

• Journal of the Korea Society for Simulation
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• v.7 no.2
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• pp.153-165
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• 1998

In the Is-95 soft handoff scheme of CDMA, there occurs a tradeoff between improving quality due to the space diversity and additional resource management like updates of the active set during soft handoffs. In addition, if a mobile terminal is alternating two adjacent cells, a well-known phenomenon called ping-ping causes the resource management to be seriously degraded. By noting that in general the probability that a user initiates additional handoffs is exponentially decreased as the user has already handed over one or more times, we present a soft handoff algorithm making use of handoff profiles of mobile terminals to improve resource utilization. In the proposed algorithm the number of handoffs made so far during the call is recorded in the mobile profile and the profile data is used for adjusting handoff parameters such as the value of add or drop threshold (T_ADD or T_DROP). Through simulations, the result of the proposed algorithm is shown to improve the handoff performance by lowering the number of handoffs while simultaneously reducing resource waste.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.1
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• pp.149-158
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• 1987

This paper describes the SEAS which is a 2-dimensional graphic editor for schematic circuit and IC mask layout. This system runs on general purpose computer and Tektronix 4110 series graphic terminal. With this system, user can edit schematic circuits and/or IC mask layout with 2 level hierarchy. This system supports more than 20 kinds of built-in symbol, user definable internal symbols, 60 macros, 16 function keys, 4 level on-screen menu operation and edit-in-place of cell in main drawing. And it provides editing functions such as reflection, rotation, move and copy of one or a group of elements, and modification of polygona geometry etc. To improve the excution speed, we used local memory of graphic terminal. For the portability of the program, the system is written in FORTRAN 77 programming language.

• Proceedings of the ESK Conference
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• 1995.10a
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• pp.62-74
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• 1995

This study surveys four characteristics (overall density, local density, grouping, complexity) to effect user's performance on the on-line terminal displays of commercial banks, and makes the new screen by the screen design procedure. The new screen includes to increase the number of groups and to arrange the items on the screen. And then, this study carrys out experiments to compare performance(operating time and error number ) by each screen. The result is described that the operating time decreases about 20% at the new OUT-screen than the existing OUT-screens; about 25% at the new IN-screen.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.364-369
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• 1992

본 논문에서는 연속 공정자동화를 위한 시스템 제어장치 중 공정의 제반운영 및 제어상태를 감시하기 위하여 공정상태를 나타내는 여러가지의 data를 그래픽 모니터상에 graphics로 표시해 주는 User Interface System인 Operator Terminal의 설계 및 구현을 다룬다. 이를 위하여 Operator Terminal은 출력장치로 VGA board와 color monitor, 입력장치로는 mouse와 function keyboard, 통신을 위한 RS232C serial port를 갖는 IBM-PC AT급의 mother board로 구성된다. 또한 program 저장은 상위 computer의 HDD를 이용한다. 그래픽 편집 및 모니터링을 위한 software는 한글 MS Windows 환경에서 구현한다.

• Proceedings of the Korea Database Society Conference
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• 1995.12a
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• pp.80-89
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• 1995

지능형 멀티미디어 워크스테이션 특징 ■ Agent-Based Computing Environment & User Interface ■ Portability with Workstation Computing Power ■ Multimedia and Intelligence ■ Easy to use ■ Easy to add functions ■ Evolution based on History of Desktop Environment ● dummy text terminal → PC → Personal Workstation → X-terminal 사용자의 특성 ■ 쉽고 편리하게 사용하기를 원하는 사용자 ■ 이동하면서 작업을 하여야 하는 사용자 ■ 데이타의 저장 및 처리보다는 주로 멀티미디어 데이터를 검색하는 사용자 ■ 멀티미디어 데이타가 주로 서버에 있는 경우와 이러한 데이터를 이용하는 사용자(중략)

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.145-154
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• 2010

End-to-End(E2E) encryption is to encrypt private and important financial information such as user's secret access numbers and account numbers from user's terminal to financial institutions. There has been found significant security vulnerabilities by various hacking in early E2E encryption system since early E2E encryption is not satisfied the basic security requirement which is that there does not exist user's financial information on plaintext in user's terminal. Extensional E2E encryption which is to improve early E2E encryption provides confidentiality and integrity to protect user's financial information from vulnerabilities such as alteration, forgery and leakage of confidential information. In this paper, we explain the extensional E2E encryption technology and present considerable security issues when the extensional E2E encryption technology is applied to financial systems.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.4
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• pp.209-214
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• 2011

This study suggests a Healthcare System for elderly and disabled who have mobility impairment and use a wheelchair for long time. Seating long time in a wheelchair without reducing pressure causes high risk of developing pressure sores. Pressure sores come with great deal of pain and often lead to develop complication. Not only it takes time and effort to treat pressure sores but also increases medical expenses. Therefore, we will develop a device to help to prevent pressure sores by measuring pressure distribution while seating in a wheelchair and wirelessly send information to user device to check pressure distribution in real time. The equipment to measure body pressure is composed of FSR sitting mat which is a sensor measuring part and an user terminal which is a monitoring part. The designed mat is matrix formed FSR sensor to measure pressure. The sensor send measured data to the controller which is connected to the end of the mat, and then the collected data are sent to an user terminal through a bluetooth. Developing a pressure monitoring system will help to prevent those who have mobility impairment to manage pressure sores and furthermore relieve their burden of medical expenses.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.3
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• pp.119-127
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• 2019

COsmicheskaya Sisteyama Poiska Avariynich Sudov Search and Rescue Satellite-Aided Tracking (COSPAS-SARSAT) is an international communication support program to perform search and rescue (SAR) operations in emergency situations by using satellite signals relayed from a beacon. The legacy COSPAS-SARSAT was originally composed of low altitude and geostationary Earth orbit satellites; thus, a limited number of directional dish antennas was sufficient to cover the limited number of visible satellites at the local user terminal. However, the second generation COSPAS-SARSAT newly added the medium Earth orbit satellites, e.g., Global Navigation Satellite Systems (GNSS) to the existing system, so that the number of visible satellites increase dramatically, and the system upgrade to cover all the visible satellites is foreseen. The additional use of planned Korea Positioning System (KPS) to existing GNSS is envisaged to provide a better performance of their SAR service. This paper presents the benefits of the additional use of KPS together with the phased array antennas at the local user terminal of the COSPAS-SARSAT. This is to effectively response to the increase of the number of visible satellites. Numerical simulation is included to evaluate the performance improvement of COSPAS-SARSAT in terms of the number of visible satellites, geometry between satellites and user, and position estimation accuracy.

• Journal of Korean Port Research
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• v.10 no.2
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• pp.7-15
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• 1996

A berth assignment problem has a direct impact on assessment of charges made to ships and goods. A berth can be assigned to incoming vessels and operated in tow different ways: as a common user berth, as a preference berth. A common user berth is a berth that any ship calling at a port may be permitted to use according to her time of arrival and to priorities as determined by the port authority. In this paper, we concerned with various types of mathematical programming models for a berth assignment problem to achive an efficient berth operation. In this paper, we focus on a reasonable berth assignment programming in a public container terminal in consideration of trade-off between server and user. We propose a branch and bound algorithm & heuristic algorithm for solving the problem. We suggest three models of berth assignment to minimizing the objective functions such as total port time, total berthing time and maximum berthing time by using a revised Maximum Position Shift(MPS) with which the trade-off between servers and users can be considered. The berth assignment problem is formulated by min-max and 0-1 integer programming and developed heuristic algorithm to solve the problem more easily instead of branch and bound method. Finally, we gave the numerrical solutions of the illustrative examples.