• Journal of Communications and Networks
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• 제10권1호
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• pp.79-88
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• 2008

In this paper, we propose efficient peer assignment algorithms for low-latency transmission of scalable coded images in peer-to-peer networks, in which peers may dynamically join and leave the networks. The objective of our algorithm is to minimize the transmission time of a requested image that is scalable coded. When an image is scalable coded in different bit rates, the bit stream encoded in a lower bit rate is a prefix subset of the one encoded in a higher bit rate. Therefore, a peer with the same requested image coded in any bit rate, even when it is different from the requested rate, may work as a supplying peer. As a result, when a scalable coded image is requested, more supplying peers can be found in peer-to-peer networks to help with the transfer. However, the set of supplying peers is not static during transmission, as the peers in this set may leave the network or finish their transmission at different times. The proposed peer assignment algorithms have taken into account the above constraints. In this paper, we first prove the existence of an optimal peer assignment solution for a simple identity permutation function, and then formulate peer assignment with this identity permutation as a mixed-integer programming problem. Next, we discuss how to address the problem of dynamic peer departures during image transmission. Finally, we carry out experiments to evaluate the performance of proposed peer assignment algorithms.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 추계학술대회
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• pp.547-548
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• 2021

본 논문에서는 SR DEVS 모델에서 자식 객체에 대한 부모 객체의 내부 상속을 고려한다. 내부 상속 함수는 상속 부모 객체가 지정될 경우 함수의 상속 처리를 수행한다. 내부 상속의 경우 부모 객체의 자산 특성에 따라 순수 상속과 부분 분열 상속으로 구분된다. 또한 상속에서 여러 자산에 대한 상속 선택이 발생할 경우 함수 처리를 요구한다. 내부 상속에 대해 선택 함수의 결정 방식을 통하여 자식 객체는 부모 객체로부터 자산을 넘겨받는다.

• 한국통신학회논문지
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• 제25권8A호
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• pp.1144-1152
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• 2000

In order to guarantee the user-requested quality-of-service(QoS) and keep the network utilization at maximum it is required to manage the network performance continuously after the network installation. The performance management function should provide the useful information for the network expansion and the capacity reallocation in the future. Currently the TINA provides the specification of the management function of configuration management connection management and fault management ; but the management function of performance management and security management are not well-defined yet. In this paper we propose a TINA-based performance management architecture for the efficient performance management of the heterogeneous networks or NEs with TMN and SNMP management functions. And we examine the proposed architecture into the ATM network (with SNMP and TMN) monitoring. The proposed architecture is based on the distributed processing architecture and the concept the TMN perfo mance management. The proposed architecture have been designed and implemented in multiprocess and multithread structure.

• 한국항행학회논문지
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• 제23권2호
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• pp.158-165
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• 2019

기존 웹 페이지는 사용자가 해당 페이지를 요청할 때 마다 새로운 페이지를 다운로드 받아 사용자에게 제공하였다. 따라서 동일한 페이지를사용자가 반복해서 요청할 경우 동일한 리소스에 대한 다운로드만을 반복하게 된다. 이는 불필요한 데이터의 소비를 발생시키는 요인이다. 본 논문에서는 사용자와 서버간의 불필요한 요청에 의해 발생하는 데이터의 소모를 감소시키고, 콘텐츠 제공 속도를 향상시키는 대에 초점을 맞추었다. 따라서 이를 방지하기 위하여 본 논문에서는 캐싱 시스템과 사용자가 요청하는 파일의 변경을 감지할 수있는 해시 함수를 이용한 해시 값의 비교를 통해 항상 최신 캐시를 유지하면서 데이터 소모를 줄일 수 있는 알고리즘에 대하여 논하고, 웹 콘텐츠의 속도 향상을 위한 서비스 워커 기반의 캐싱 시스템을 설계하고 성능을 평가하였다.

• 한국통신학회논문지
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• 제34권2B호
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• pp.203-211
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• 2009

방송 통신융합 현상이 나타남에 따라 인증기준이 제정되지 않은 상황에서 제조자가 제품에 대한 출시 승인을 요청하는 상황이 빈번하게 발생하고 있다. 그럼에도 불구하고 이러한 상황에 대처할 수 있는 행정처분절차는 부재한 상황이다. 이러한 관점에서 본 연구는 잠정인종제도(잠정행정처분제도), SDoC와 기술기준의 민간화제도 등을 해결책으로 제시하였다. SDoC와 기술기준 민간화제도의 도입은 원천적으로 기술기준이 존재하지 않는 제품의 등장을 최소화시킬 수 있으며, 잠정인증제도는 기술기준이 부재한 경우에 행정적 해결책을 제시할 수 있을 것이다.

• 한국건설관리학회논문집
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• 제5권3호
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• pp.88-96
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• 2004

고객 요구사항은 기업의 여러 성과와 관련하여 최근 이에 대한 관심이 증가되고 있는 개념이며, 특히 국내 건설업에서 큰 비중을 차지하는 아파트 사업의 경우 다각도의 조사를 통해 고객의 요구사항을 발굴하고 이를 사업에 반영하여 품질을 향상시키는 노력이 필요하다. 이를 위해서는 고객의 요구사항을 파악하고 아파트 사업에 적용하는 기법이 요구되며 QFD(Quality Function Deployment)와 연계된 ROQ(Return On Qualify)는 제조업에서 사용되는 기법으로 고객의 요구사항을 조사하여 고객만족을 향상시키고 이를 품질개선 프로그램에 적용해 수익성을 향상시키게 하는 프로세스이다. 본 연구에서는 ROQ 프로세스의 적용을 통해 아파트 품질관리 개선방안을 제시하였다. 이를 위해 먼저 소비자 면접조사와 FGI(포커스그룹 인터뷰) 조사 실시 및 고객의 요구사항을 분석하였으며, 그 후 전문가의 면담을 통해 새로운 아파트 상품 개발에 적용 가능한 품질개선 프로그램을 수립하였다. 이 프로세스를 통해 새로운 아파트 품질관리 개선방안을 제시하도록 한다.

• 대한인간공학회지
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• 제28권4호
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• pp.51-59
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• 2009

These days mobile phone which were used mainly by grown-up persons are now widely used among children as well due to new social demands. Despite this trend, existing mobile phones are still being designed and produced according to the taste of people in their 20s and 30s, even the elderly, not satisfying physical, emotional and cognitive characteristics raised by children. This study aimed to extract the design factors of mobile phones for children by reflecting functional factors requested by children and parents in QFD's customer demands. First, functional and design factors requested in mobile phones for children were extracted from existing products and documentary records and some functional factors were selected through a process of integration and omission. The survey research was conducted on children and parents, based on the selected functional factors. Based on the survey research, functional factors were analyzed using AHP, and key functional factors considered by children and parents in mobile phones for children were investigated. Finally, in order to reflect the results in QFD, the correlation between functional factors and design factors was constructed as HOQ through experts' evaluation. The results showed that both children and parents recognized the basic functions such as telephoning, text messaging and phone directory as high priority functional factors, even though the relative importance was different between children and parents. Therefore, it is likely to satisfy the desires of both children and parents by designing mobile phones for children in consideration of design factors such as menu depth, button independence and button arrangement. It is expected that this study will promote experiments on design factors and propose basic data for and guidelines to mobile phone design for children.

• 한국관개배수논문집
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• 제18권2호
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• pp.142-160
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• 2011

This study was performed to apply the preventive management technique that is known for more economic and preventive for disaster than corrective technique to Repair & Improvement(R&I) Project policy of irrigational facilities. The appropriate periods of R&I Project had been driven to 40yrs, 24yrs, 27yrs, and 29yrs for reservoir, Pumping and drainage pumping station, Diversion weir and Irrigation & drainage canal respectively. The cost of R&I Project for 10 years had been estimated as 616.9 billion won per year including the 85 billion won for the project of 'Disaster prevention and Function continuity'. After the period of 'Improvement all at once', about 30yrs, 421.8 billion won was requested for 'Function continuity'.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.735-736
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• 2008

There are many equipments for the Short Circuit Test, for example Short Circuit Generator, Induction Motor, Sequence Timer, CLR, Back Up Breaker, Making Switch and Excitation Equipment etc. Gradually an allowable tolerance of the short circuit test voltage is become smaller by the standards for short circuit test. The excitation equipment of short circuit generator is very important for test voltage is adjusted by the excitation equipment. Especially the excitation equipment must be possessed character of exactitude, durability and inalterability because some times around 10,000 times opening and closing short circuit test is requested by clint, which must be done within one minute. The purpose of this study for function and operation of the excitation equipment which rated DC voltage is 1,000V, rated DC current is 300A, rated out put is 30kW and type is YNEX 97S-441/609, is to help operation of short circuit generator.

• 천문학회보
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• 제38권1호
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• pp.64.1-64.1
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• 2013

The point spread function (PSF) of an optical system is in general defined as a two-dimensional intensity distribution which results from a single point source at infinity. It is an important key for the evaluation of the optical performance of an astronomical telescope. The PSFs of the soft X-ray telescope (SXT) aboard Yohkoh were measured in a wide range of the field-of-view under the in-flight configuration at White Sands Missile Range prior to launching the satellite. It has been known that the SXT PSF has a sharp peak at the core and the intensity drops very fast as it goes distant from the center. Due to the combination of this sharp peak at the PSF core and the effect of undersampling by a large pixel size, a carefully designed method is requested in the examination of the PSF data. The pattern of the SXT PSF is determined by the fitting of a mathematical functional form to the pre-launch experimental data. The elliptical Moffat function has been adopted for the evaluation of the SXT PSF. It is revealed from our study that the SXT PSF shows a peculiar characteristics, and thus a careful consideration on the undersampling effect and also a proper choice of statistics are necessary for the determination of the best fit function of the PSF. Details on the on- and off-axis SXT PSF in the field-of-view will be introduced and discussed in our presentation.