• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.89-95
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• 2003

In this study, the technical characteristics of geosynchronous multi-mission satellites are investigated, compared to communication satellites. Geosynchronous meteorological satellites, whose imaging data is normally shared with the international society, have large coverage for monitoring and data service. Also the higher pointing accuracy is requested to keep the spatial resolution of 1-4km, compared to those of communication satellites. Cryogenic thermal control is needed for the better performance of IR sensors and the contamination protection of optical parts should be considered. On the other hands, for the successful development of the multi-mission satellite COMS, which will be launched in 2008, the special features of attitude control, electrical power, thermal control and mechanism are investigated.

• Journal of Digital Contents Society
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• v.5 no.1
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• pp.7-11
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• 2004

There are many problems that must solve to construct next generation high-speed communication network. Among these, item that must consider basically is characteristics analysis of traffic that nows to network Traffic characteristics of many Internet services that is offered present have shown that network traffic exhibits at a wide range of scals-self-similarity. Self-similarity is expressed by long term dependency, this is contradictory concept with Poisson model that have relativity short term dependency. Therefore, first of all, for design and dimensioning of next generation communication network, traffic model that are reflected burstiness and self-similarity is required. Here self-similarity can be characterized by Hurst parameter. In this paper, the calculation equation is derived considering queueing delay and self-similarity of data traffic art compared with simulation results.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.68-70
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• 2023

COVI-19 이후 콜드체인 시스템의 중요성이 증가함과 함께 냉동물류센터에 대한 중요성도 부각되고 있다. 향후 냉동물류센터의 양적·질적 팽창은 불가피하며 그에 따른 위치선정의 중요성도 커지고 있다. 하지만, 대다수의 국내 냉동물류센터는 단순보관의 역할 위주에, 도심이나 주요도로와 멀리 떨어져 있고, 노후화의 문제를 가지고 있다. 또한 냉동물류센터는 에너지 소비가 많은 만큼 위치선정에 따른 비용문제도 큰 영향을 미친다. 따라서 본 연구는 AHP를 활용하여 부산 경남 냉동 물류 센터의 위치 경쟁력 결정 요인을 분석하고자 한다. 시설요인, 서비스 요인, 위치 요인, 그리고 비용 요인의 네 가지 영역과 이를 세부적으로 나누어 19개의 항목을 계층화하여 상대적 중요도를 평가하였다. 연구결과는 냉동물류센터의 입지결정요인과 기존에 냉동물류센터에 요구되던 기본적인 요소에 입지경쟁력 분석을 위한 우선 순위를 계층화하였다. 비용요인이 국내 냉동물류센터 입지경쟁력의 결정요인 중 가장 높은 비중을 차지하였다. 실제 시설인프라와 물류연결성은 관련 업종 근무자들이 가장 민감하게 받아들이는 사항이기도 하며 새로운 냉동물류센터의 도입 시에도 필수적으로 참고가 되어야할 것으로 보인다. 본 연구는 냉동물류센터 종사자 및 관련업계 종사자들이 어떠한 요인을 냉동물류센터의 입지경쟁력 결정요인으로 비중 있게 고려하고 있는지를 도출하였고, 향후 입지경쟁력 향상을 위한 전략적 시사점을 제공한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6B
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• pp.495-507
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• 2006

In wireless local area networks (WLANs), the successful design of scheduling algorithm is a key factor in guaranteeing the various quality of service (QoS) requirements for the stringent real-time constraints of multimedia services. In this paper we propose a multipolling-based dynamic scheduling algorithm for providing delay guarantees to multimedia traffics such as MPEG streams. The dynamic algorithm exploits the characteristics of MPEG stream, and uses mini frames for feedback control in order to deliver dynamic parameters for channel requests from stations to the point coordinator (PC) operating at the access point (AP). In this scheme, the duration of channel time allocated to a station during a superframe is changed dynamically depending on the MPEG frame type, traffic load and delay bound of the frame, etc. Performance of the proposed scheme is investigated by simulation. Our results show that compared to conventional scheme, the proposed scheme is very effective and has high performance while guaranteeing the delay bound.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.1-12
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• 2005

In wireless personal area networks(PANs), the successful design of channel time allocation algorithm is a key factor in guaranteeing the various quality of service(QoS) requirements for the stringent real-time constraints of multimedia services. In this paper we propose a dynamic channel time allocation algerian for providing delay guarantees to multimedia traffics such as MPEG streams in the IEEE 802.15.3 high-rate WPANs. The dynamic algorithm exploits the characteristics of MPEG stream, wherein the devices (DEVs) send their channel time requests only at the end of superframe boundaries. The algerian uses mini packets for feedback control in order to deliver dynamic parameters for channel time requests from the DEVs to the piconet coordinator (PNC). In this scheme, the duration of channel time allocated to a DEV during a superframe is changed dynamically depending on the MPEG frame type, traffic load and delay bound of the frame, etc. Performance of the proposed scheme is investigated by simulation. Our results show that compared to traditional scheme, the proposed scheme is very effective and has high performance while guaranteeing the delay bound.

• Journal of the Korea Society of Computer and Information
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• v.26 no.3
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• pp.69-75
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• 2021

Limitation of the TCP/IP network technology included in the vehicle communication is due to the frequent mobility of the vehicle, the increase in intermittent connection requirements, and the constant presence of the possibility of vehicle hacking. VNDN technology enables the transfer of the name you are looking for using textual information without the need for vehicle identifiers like IP/ID. In addition, intermittent connectivity communication is possible rather than end-to-end connection communication. The data itself is the subject of communication based on name-based forwarding using two types of packets: Interest packet and Data packet. One of the issues to be solved for the realization of infotainment services under the VNDN environment is the traffic explosion caused by data broadcasting. In this paper, we analyze and compare the existing technologies to reduce the data broadcast storm. Through this, we derive and analyze the requirements for presenting the best data mitigation technique for solving the data explosion phenomenon in the VNDN environment. We expect this paper can be utilized as prior knowledge in researching improved forwarding techniques to resolve the data broadcast explosion in connected vehicles over NDN.

• Journal of agriculture & life science
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• v.43 no.2
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• pp.65-78
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• 2009

The purpose of this research is to analyze the factors influencing satisfaction level of consumers using internet shopping mall to purchase agricultural products and to check relationship between satisfaction factor and intention in current situation of fast diffusion of market size for agricultural product e-commerce. Purchase motivation in internet shopping mall was shown to be the reason of convenience rather than confidence degree for agricultural product consumers. Consumer satisfaction factor of agricultural product internet shopping mall can be distinguished by confidence in service quality, diversity of products, delivery and customer support, and security. The result of this research will help us understand the determination factor of consumer satisfaction and their intention about internet shopping, while finding out what consumers expect from internet shopping when purchasing agricultural products.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.33 no.1
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• pp.499-519
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• 2022

This study empirically analyzed how users and librarians perceive the roles and functions of the future public library through a survey and suggested what should be considered in establishing the future direction of the development of future library. As a result of the analysis, both librarians and users aware that contents were the most important aspect in the operation of future public libraries. In addition, users perceive the importance of information services higher than librarians, which shows that future public libraries require to develop and offer various information services. In contrast, the adoption of the latest information technology showed relatively low awareness of its importance in future public libraries. Therefore, the use of content and the provision of various channels and tools to satisfy information needs were perceived as more important than the adoption of information technologies.

• Journal of Industrial Convergence
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• v.21 no.10
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• pp.65-80
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• 2023

Through inductive content analysis, this study sought to examine the crisis experienced by the institution, the quality of service, and the distrust of the system and institution based on the experience of distrust in the home-visiting care service of bbeneficiary and guardians. FGI was conducted on five managers of institutions that provide home-visiting care services. As a result, the central phenomenon was found: deterioration of service quality, distrust of systems and institutions, and difficulties in opera-ting long-term care institutions. In order to improve the quality of home-visited care services and build trust in care workers and institutions, first, home-based associations or operating corporations should develop new education program plans and manuals to strengthen the capabilities of care workers and social workers. Second, the NHIS's monitoring system and the professional management system of care workers should be established. Third, it is necessary to improve awareness of the role, expertise, and rights of care workers, and fourth, improvement measures are required to reduce the turnover rate of care workers, which is the cause of the deterioration of the quality of long-term care services.

• Journal of Korean Society of Archives and Records Management
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• v.15 no.3
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• pp.193-217
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• 2015

The main purpose of this study is to analyze the educational effectiveness of historical thinking contents through the experimentation methodology. The procedures of this study will review foreign and domestic historical thinking cases of archival contents for history education; derive some implications from the review; and apply the implications to classes targeted for first year high school students. It can be said that classes utilizing historical thinking contents have beneficial effects on the subcategories of historical thinking, that is, chronology comprehension ability, historical inquiry ability, historical imagination, and historical judgment ability. The average between before and after examination results shows a statistically meaningful difference. In addition, this study shows that students obtain better scores after examination than before.