• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.2
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• pp.11-19
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• 1999

The design procedure as well as some test results of a low-cost commercial radome for mobile DBS(Direct Broadcasting Satellite) receiving antenna system are presented in this paper. At first the complex permittivity of dielectric material should be measured in order to select a material for radome design. The complex permittivities of low-cost plastics supplied by domestic vendors are measured and presented. And then the transmission losses of the sheets are calculated. The calculated results are verified by the measurements of wave transmission test of that sheets. Two kinds of radomes, ABS single-layer and A-Sandwich((PET-Foam-ABS), are fabricated and measured practically. The transmission losses of single-layer and A-sandwich radome are 1.5dB and 0.6dB respectively at the maximum wave incident angle of 57 degree. Also the calculated crosspolarization caused by A-sandwich radome is under 20dB.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.11a
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• pp.67-68
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• 2001

제지공장은 에너지 다소비 업종이며 고도의 장치산업이기 때문에 초지 설비의 효과적 운영을 통한 생산성 극대화가 경제성과 직결되어 었다. 또한 24시간 연속생산을 하는 초지 설비로 소비자가 선호하는 품질의 종이를 생산하기 위해서는 공정의 안정성 이 매우 중요하다. 이는 공정의 불안정화는 생산제품의 품질 변화를 유발함으로써 균일 성을 저하시키는 악영향을 미치기 때문이다. 제지 공정의 안정화를 저해하는 인자에는 지절, 지종 변화, 조업중단, 조업재개 둥과 공정의 특성상 수반되는 돌발사태 등이 있을 수 있다. 이들 인자 가운데 가장 심각하게 공정의 안정성을 악화시키는 것은 지절의 발 생이라 할 수 있다. 지절이 발생되면 생산성 저하 등의 여러 문제점이 발생하기도 하지 만 다량의 파지가 발생되기 때문에 공정 안정성 면에서 볼 때에도 부득이하게 생성된 다량의 파지를 공정에 재투입하기 위해 재해리해야하므로 많은 양의 백수가 소모되며 이에 따라 예기치 않은 공정 백수의 사용으로 전체 백수계에 갑작스런 변동이 생기게 된다. 백수가 파지의 해리에 사용됨에 따라 공정 내에는 추가적인 청수가 공급되어야 하므로 전체적으로는 청수의 사용량도 늘어난다. 또한 증가된 파지의 재사용도 대부분 의 공장에서 broke chest의 용량이 한정되어 있으므로 이의 적절한 컨트롤은 중요하다. 더욱이 점차 공정이 고폐쇄화됨에 따라 공정 컨트롤에 대한 여유가 적으므로 백수와 공정의 관리는 점차 어려워지고 있다. 공정 시율레이션은 현존하는 공정을 수학적으로 모델화하여 이를 컴퓨터 하드 왜어를 이용해 실제 공장에서 일어나는 상황을 모사하는 것이다. 이러한 공정 모사는 새로운 공장을 설계하기 전에 타당성 조사와 여러 가지 사례조사를 실시할 때, 기존 공 장의 개조나 증설 또는 기존 공장의 운전조건을 실제로 변경하기 전에도 미리 모사를 함으로써 실제 시험 운전을 하는 경우 보다 많은 비용과 시간을 절약할 수 있다. 본 연 구는 백상지 생산 공정 설계도면을 참고하여 상용 시율레이터로 시율레이션 모델을 구 축하고 이를 기반으로 지절 상황을 모사하였으며, 지절 후의 공정 불안정화 상황을 파 악하였다. 또한 이러한 상황의 대책을 강구하기 위해 다양한 공정 조절 방안을 시율레이션 모댈에 적용하여 그 결과를 해석하였다.

• The KIPS Transactions:PartB
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• v.9B no.3
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• pp.311-318
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• 2002

Document image layout analysis contains the process to segment document image into detailed regions and the process to classify the segmented regions into text, picture, table or etc. In the region classification process, the size of a region, the density of black pixels, and the complexity of pixel distribution are the bases of region classification. But in case of picture, the ranges of these bases are so wide that it's difficult to decide the classification threshold between picture and others. As a result, the picture has a higher region classification error than others. In this paper, we propose document image layout analysis method which has a better performance for the picture and text region classification than that of previous methods including commercial softwares. In the picture and text region classification, median filter is used in order to reduce the influence of the size of a region, the density of black pixels, and the complexity of pixel distribution. Futhermore the classification error is corrected by the use of region expanding filter and constrained conditions.

• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.637-643
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• 2007

In many fields, commercial programs or equipments are biting developed and these are getting complicated more and more by adding advantages from existing products. In promoting the usability of these products, design based on the information integration receives attention. However, is information integration always better? In this study, we tried to demonstrate information distribution is more efficient than information integration through conning display design that was propelled by many countries' classification societies. We designed the conning display using many ergonomic methods and conducted its performance experiment. Results of the performance experiment reveal that conning display having two modes (one shows the functions related with ocean and coast voyage and another shows the functions related with docking and leaving port) is more efficient.

• The KIPS Transactions:PartA
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• v.15A no.5
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• pp.259-268
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• 2008

Multi-Core processors have become main-stream microprocessors in recent years. Servers based on these multi-core processors are widely adopted in High Performance Computing (HPC) and commercial business applications as well. These servers provide increased level of parallelism, thus can potentially boost the performance for applications. However, the shared resources among multiple cores on the same chip can become hot spots and act as performance bottlenecks. Therefore it is essential to optimize the use of shared resources for high performance and scalability for the multi-core servers. In this paper, we conduct experimental studies to analyze the positive and negative effects of the resource sharing on the performance of HPC applications. Through the analyses we also characterize the performance of multi-core servers.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.2
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• pp.95-102
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• 2013

Exfoliated graphite (EFG) with high aspect ratio was incorporated with high density polyethylene (HDPE) for use as high barrier packaging material such as water-sensitivity electric product and pharmaceutical packaging. Also HDPE/EFG nanocomposite films were prepared by adding the compatibilizer for effective dispersion and compatibility. Their chemical properties, crystal structure properties, thermal properties and water barrier properties of as-prepared HDPE/EFG nanocomposite films were investigated as a function of EFG contents. It showed that there is a weak interfacial interaction between HDPE and EFG, however, the water vapor permeations were decreased from 127 to 78 (70 ${\mu}m{\cdot}g/m^2$, $day{\cdot}atm$) by addition of EFG. Especially, the physical properties of HDPE/EFG nanocomposite films were effectively increased up to 0.5 wt%, however, there were no significant improvement of properties in nanocomposite films at the additional EFG loading. To maximize their performance of the nanocomposite films, further research is required to enhance the dispersion of EFG and compatibility of EFG in HDPE matrix.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11a
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• pp.87-95
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• 2005

Laser sealing/cutting technique, one of the 4 core technologies to manufacture self-luminous glass tubes (SLGTs) has been developed. Through the analysis of commercial products it is found that Pyrex Is used for SLGTs. A CO2 laser, which is commonly used for glass work was used for the study The factors affecting the sealing/cutting were laser intensity, duration. Irradiation method, and pressure inside the tube. The whole Process is composed of 2 stages. In the first stage. both ends of the tubes are sealed while tritium is insected in the tubes. And the tritium sealed tubes are cut in the desired size in the second stage. Defocused beam was used for seal ing and focused beam was used for cutting. After the sealing/cutting, the tubes were heat treated to prevent fracture due to the residual heat stress.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.233-244
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• 2008

A conceptual design study for a pyroprocesing facility, has been carried out in this study, which is available for the recovery of uranium and transuranic elemental group(TRU), that is, reusable as a nuclear fuel especially in a next generation-type reactor. The scale of this facility has been chosen as 20 kg HM/batch, comparatively small engineering size in order to collect scale-up data for the design of a commercial facility as well as to get operational experience. The spent fuel to be handled in this process is as follows : 3.5 % enriched uranium fuel, 35,000MWd/tU and 5-year cooled. The major items considered in the conceptual study are a building lay-out including various hot cells, safety management of the process operation in conjunction with material balance control, radiation safety, inert atmosphere control in shielded hot cells, and criticality control of uranium and TRU products.

• Journal of Advanced Navigation Technology
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• v.3 no.2
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• pp.132-138
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• 1999

This paper describes the development of an automatic dependent surveillance system(ADS) with Java on Web environment. The ADS consists of a server module and a client one. The server module performs a database server for gathering GPS data from airplanes. It also dose an Web server function for sending Java applet to clients. The applet enables each client to obtain the current flight information from the server via the Internet without a special client software. This client-server based ADS with Java environment has several advantages over other systems. One is not to need for installing special client software on each client system. The other is its simplicity on system maintenance. The reason why it has simplicity is to require only server program modification including the applet without updating client software. After testing the ADS system with the flight information of a Mooney, we can show that the prototype system can be a candidate for developing commercial products.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.354-362
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• 2015

In this study, for integrated management and inter-exchange of operational data generated by ships and land-side information on safe and business, a vessel communication system with modular functions was designed that applied high efficiency compression, least-cost algorithms and Inmarsat FBB connection automation system. Performance test at the KTsat Kumsan satellite earth station; system was found to delivered an average transfer speed of 7 kB/S, which was significant improvement from the existing commercial product's average speed of 5 kB/S. It also delivered twice the efficiency of the existing product in terms of compression rate and transfer of the most widely used office files in maritime businesses.