• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.163-166
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• 2009

다중접합 초 고효율 태양전지 제조를 위해 SiC 매트릭스를 이용한 실리콘 양자점 초격자 박막을 제조하고 특성을 분석하였다. $SiC/Si_{1-x}C_x$(x ~ 0.31)로 실리콘 양자점 초격자 박막을 Si과 C target을 이용한 co-sputtering법으로 초격자 박막을 제조하고, $1000^{\circ}C$에서 20분간 열처리를 하였다. high resolution transmission electron microscopy 사진으로 약1~7nm 크기인 양자점 생성과 분포 밀도를 확인할 수 있었으며, grazing incident X-ray diffraction (GIXRD)를 통해서 Si(111)과 $\beta$-SiC(111)이 생성되었음을 알 수 있었다. Auger electron spectroscopy (AES)측정에서 stoichiometric SiC층과 Si-rich SiC층의 Si 원자농도 (56%, 69%)와 C 원자 농도 (44%, 31%)를 알 수 있었으며, Fourier transform infra-red spectroscopy (FTIR)측정에서 SiC 픽의 위치가 767에서 $800cm^{-1}$으로 이동하는 것을 알 수 있었다.

• Membrane and Water Treatment
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• v.7 no.4
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• pp.355-365
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• 2016

The improvement of fouling resistance of porous polymeric membrane is one of the most important targets in membrane preparation for water purification in many process like wastewater treatment. Membranes can be modified by various techniques, including the treatment of polymer material, blending of hydrophilic polymer into polymer solution, and post treatment of fabricated membrane. This research proposed the modifications of morphology and surface property of hydrophobic membrane by blending polyethersulfone (PES) with three polymeric additives, polyvinylpyrrolidone (PVP), Pluronic F127 (Plu), and Tetronic 1307 (Tet). PES hollow fiber membranes were fabricated via dry-wet spinning process by using a spinneret with inner and outer diameter of 0.7 and 1.0 mm, respectively. The morphology changes of PES blend membrane by those additives, as well as the change of performance in ultrafiltration module were comparatively observed. The surface structure of membranes was characterized by atomic force microscopy and Fourier transform infra red spectroscopy. The cross section morphology of PES blend hollow fiber membranes was investigated by scanning electron microscopy. The results showed that all polymeric additives blended in this system affected to improve the performances of PES membrane. The ultra-filtration experiment confirmed that PES-PVP membrane showed the best performance among the three membranes on the basis of filtration stability.

• Journal of the Korean Society for information Management
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• v.30 no.3
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• pp.249-271
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• 2013

The purpose of this study is to develop a collaborative print journal preservation model for the medical libraries in Korea. After reviewing previous studies and advanced preservation practices, a survey was administered to the members of the Korean Medical Library Association to collect data about the present states of journal weeding and storage space as well as their needs and preferences for collaborative preservation. Based on the analysis, a hybrid model, consisting of centralized and distributed archives, is proposed with MEDLIS as infra structure. Detailed characteristics and three phases of implement strategies are described. Finally, recommendations for the Korean Medical Library Association to the successful substantiation are suggested.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.3097-3110
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• 1997

As to the recent advances in computer technologies and high-speed networks, telecommunication services and provision of multimedia services will be provided on the basic of a new software architecture adapting networking infrastructure on open information networking architecture. In this paper, the video conference services has been selected as a target service example because it is expected to become one of the most important services on the full service network. In fact, it can be viewed as the basis for providing telecommunication services such as video telephony and video conferencing. This paper presents the prototyping of TINA (Telecommunication Information Networking Architecture) based desktop video conference system using the concepts of session management. The prototyping of desktop video conference system aims at assessing TINA concepts and refinement of the mapping between session graph and connection graph, and provides object modeling methodologies towards distribution and objected-orientation.

• Journal of Positioning, Navigation, and Timing
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• v.8 no.4
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• pp.153-164
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• 2019

This paper presents the development of an end-to-end numerical simulator for signal design of the next generation global navigation satellite system (GNSS). The GNSS services are an essential element of modern human life, becoming a core part of national infra-structure. Several countries are developing or modernizing their own positioning and timing system as their demand, and South Korea is also planning to develop a Korean Positioning System (KPS) based on its own technology, with the aim of operation in 2034. The developed simulator consists of three main units such as a signal generator, a channel unit, and a receiver. The signal generator is constructed based on the actual navigation satellite payload model. For channels, a simple Gaussian channel and land mobile satellite (LMS) multipath channel environments are implemented. A software receiver approach based on a commercial GNSS receiver model is employed. Through the simulator proposed in this paper, it is possible to simulate the entire transceiver chain process from signal generation to receiver processing including channel effect. Finally, numerical simulation results for a simple example scenario is analyzed. The use of the numerical signal simulator in this paper will be ideally suited to design a new navigation signal for the upcoming KPS by reducing the research and development efforts, tremendously.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.756-760
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• 2005

By development of a robot technology, personal robot is being developed very actively. Various infra-technologies are accumulated in hardware and software how by internal a lot of research and development efforts, and it is circumstance that actual commodity is announced. But, personal robot is applied to be acting near human, and takes charge of safety and connected directly a lot of works of home security, gas-leakage, fire-warning facilities, or/and etc. So personal robot must do safe and stable action even if any unexpected accidents are happened, important functions are always operated. In this paper, we are wished to show design structures for supporting fault-tolerant operation from our real-time robot middleware viewpoint. Personal robot, in being developed, was designed by module structure to do to interconnect and to interoperate among each module that is mutually implemented by each research facilities or company. Also, each modules can use appreciate network system that is fit for handling and communicating its data. To guarantee this, we have being developed a real-time network middleware, for especially personal robot. Recent our working is to add and to adjust some functions like connection management, distributed routing mechanism, remote object management, and making platform independent robot application execution environment with self-moving of robot application, for fault-tolerant personal robot.

• Journal of Korea Port Economic Association
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• v.22 no.4
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• pp.59-79
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• 2006

In this paper, we analyse the comparative competitiveness of the 10 major logistic hub cities in China. First, using the input distance function, we calculated the technical efficiencies and the opportunity costs of the transport infra structure investments. Then, based on not only these supply side factors but also demand side, the overall comparative competitiveness by cities are analyzed. Our main findings are as follows: early developed, larger cities such as Shanghai, Guangzhou, Shenzhen are technically efficient but their opportunity costs of the additional transport investments are higher than the other cities. We also found that overall competitiveness of these larger and leading logistic hub cities are dominant over the small and newly developed logistic cities.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.709-712
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• 2010

A military tactical information communication network uses no base station and all mobile terminal are independent while mobile networks use an infra structure that a fixed base station supports many mobile terminals. A clustering system is more efficient than the existing one in small Ad-hoc network using a limited message size. The development of an adaptive clustering algorithm is necessary to maximize the network efficiency via a study on a clustering for military tactical information communication network.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.876-881
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• 2006

This study was carried out to understand depositional environment and genesis of clayey soils that distributed in the Dongup area. On the basis of detailed observation and description on mineralogy, geochemical composition, geophysical properties, paleontological analysis of cored sediments, three sedimentary unit have been distinguished. From bottom to top, they are early Holocene freshwater muddy deposit(Unit I, fluvial swamp), late Holocene silt and muddy deposit(Unit II, alluvial deposit), late Holocene muddy deposit(Unit III, fluvial swamp). Unit II is divided into three part: the lower part-unweathered massive silt and muddy deposit, middle part-weathered layered slit and muddy deposit and upper part-weathered massive muddy deposit.

• KIEAE Journal
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• v.1 no.1
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• pp.45-52
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• 2001

This study aims to make a fundamental data for a policy-making decision in treatment and disposal of municipal solid wastes and presents a research data on the discharge properties of municipal solid wastes and making a unit of them in the Taegu metropolitan city. The results can be summarized as follows; survey the discharge properties of municipal solid wastes, calorific values and to present a research-data in supplying incineration-heat of wastes with the area of Sung-seo in Taegu. So, using fundamental data for planning and running wastes-incineration plants as well as trying to make better Urban Environmental Infra-structure. The results are obtained from the study. 1) The proportion of combustible wastes in Taegu increased from 89.6% to 94.47% during 1993~2000. However, the proportion of incombustibles decreased from 10.4% to 5.53% during 1993~2000. 2) The value of representative properties is about 1500~2000kcal/kg. So we can expect that it should be made use of energy-resources positively. 3) The heat from Sung-seo wastes-incineration plants is used to produce electronic-energy for wastes-incineration plants in summer season. The heat from Sung-sea wastes-incineration plants is in charge of 27% which of supplying the area of Sung-seo with district heating energy in winter season.