• Korean Journal of Remote Sensing
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• v.28 no.4
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• pp.467-475
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• 2012

Cloud computing services are known that they have many advantages from the point of view in economic saving, scalability, security, sharing and accessibility. So their applications are extending from simple office systems to the expert system for scientific computing. However, research or computing technology development in the geo-spatial fields including remote sensing applications are the beginning stage. In this work, the previously implemented smartphone app for image processing was first migrated to mobile cloud computing linked to Amazon web services. As well, parallel programming was applied for improving operation performance. Industrial needs and technology development cases in terms of mobile cloud computing services are being increased. Thus, a performance testing on a satellite image processing module was carried out as the main purpose of this study. Types of implementation or services for mobile cloud varies. As the result of this testing study in a given condition, the performance of cloud computing server was higher than that of the single server without cloud service. This work is a preliminary case study for the further linkage approach for mobile cloud and satellite image processing.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.338-338
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• 2012

사파이어 ($Al_2O_3$)는 높은 밴드갭 에너지 (~19.5 eV)를 가진 물질로서 우수한 내마모성, 강도, 전기 절연성 및 안정한 화학적 특성을 갖고 발광다이오드 기판, 보석재료 등 각종 산업 및 기술적 분야에서 널리 사용되고 있다. 특히, 플립칩 발광다이오드 구조의 경우 광추출효율을 향상시키기 위해 높은 투과도를 갖는 사파이어 기판이 요구되어 왔으며, 지금까지 건식/습식식각방법을 이용한 사파이어 표면에 마이크로 크기의 심한 거칠기 또는 요철이 형성된 나노크기의 격자구조를 형성시키는 연구가 진행되어 오고 있다. 그 중, 나노 크기의 격자구조는 공기에서 반도체 기판까지 선형적인 유효굴절률 분포를 갖기 때문에 표면에서 생기는 Fresnel 반사 손실을 줄일 수 있다. 이러한 구조를 형성하기 위해서는 식각 마스크가 필요한데, 형성 방법으로 레이저 간섭 리소그래피, 전자빔 리소그래피, 나노임프린트 리소그래피 등이 있으나, 비싼 가격과 복잡한 공정 절차 등의 단점을 지니고 있다. 따라서 본 연구에서는 식각 마스크 패턴을 위해, 보다 저렴하고 간단한 실리카 나노구 및 열적응집 금 나노 입자를 이용하였다. 양면 폴리싱 c-plane 사파이어 기판을 사용하였고, 단일 층의 주기적인 실리카 나노구를 기판 표면에 스핀코팅에 의해 도포한 후 유도결합플라즈마 식각 장비를 이용하여 식각하여 주기적인 패턴을 갖는 렌즈모양의 격자구조를 형성하였다. 그리고 주기적으로 형성된 격자 위에 열 증착기를 이용하여 금 박막을 증착한 후 급속열적어닐닝(rapid thermal annealing)을 이용하여 열처리함으로써 비주기적인 금 나노입자를 형성시켰다. 형성된 금 나노패턴을 이용하여 동일한 조건으로 식각함으로써 광대역 및 전방향성 높은 투과도를 갖는 원뿔 모양의 사파이어 나노구조를 제작하였다. 제작된 샘플의 패턴 및 식각 형상은 전자현미경을 사용하여 관찰하였으며, UV-vis-NIR 분광광도계 (spectrophotometer)를 사용하여 투과율을 측정하였다. 렌즈 모양 표면 위에 원뿔모양의 나노구조를 갖는 사파이어 기판은 일반적인 사파이어 기판보다 향상된 투과율 특성을 보였다.

• Spatial Information Research
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• v.8 no.2
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• pp.191-201
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• 2000

Recently, tourism industry is on the trend of expanding its activity arena, boosted by revitalization of regional economy and reorganization of urban environment, undertaken for the purpose of place marketing. However, Korea has not been able to develop a variety of tourism itineraries that can attract the interest of tourists because most tourism resources are isolated with single function. This constraint has prevented tourism industry in Korea from attaining competitiveness. In attempting to overcome this constraint, this study seeks to develop tourism itineraries by constructing and utilizing database on historical and cultural tourism resources based on the case of Kangneung City. Through the construction of information system on historical and cultural resources and tourism support facilities, optimal tourism itineraries that take into account maintenance conditions, types, values, lodging availabilities and accessibility of tourism resource areas can be developed. Moreover, it is expected that this information system will have a high level of usage in the future, for it can provide a wide range of tourism services on the internet and education materials as well as facilitate resources management.

• Journal of Advanced Navigation Technology
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• v.24 no.3
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• pp.212-217
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• 2020

Recently, with the interest in the 4th industrial revolution, the demand for autonomous driving technology is increasing. V2X communication technology is a core technology for autonomous vehicles that exchanges information with objects such as vehicles, infrastructure, networks, and pedestrians through wired and wireless networks. In this paper, we present the results of the hybrid V2X communication system, which is a hybrid design of WAVE and LTE, and the coverage test to confirm the performance of the system. Through coverage measurement, we show that the hybrid V2X communication performance is superior to the existing LTE or WAVE single communication system in communication coverage, so it can be effectively applied to autonomous driving services.

• Korean Business Review
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• v.12
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• pp.239-254
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• 1999

There has been a lot of researches on the major motivation of consumer's choice for airlines. Due to the competition in airline industries, most of airlines offer a various level of benefits to customers such as a frequent traveller bonus, a schedule, services in flight including a meal and an entertainment program, a discounted fare and an intangible part of personal service. However, it is very difficult to measure the performance of the customers' benefit and to identify the weight of each factor being considered on the airline choice. In this paper, we focus on the airline choice process for the business travellers. The AHP is applied to evaluate the factors reflecting the business travellers' choice for airlines. This study will be useful to build a marketing plan for the business traveller's market.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.40.2-40.2
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• 2011

초경합금은 경도가 높은 재료를 말하며 일반적으로는 탄화텅스텐(WC)계 재료를 말한다. 국내 현재 초경합금 동향은 반도체 산업, 내마모성 공구, 절삭공구, 금형 등 많은 분야에 사용되어지고 있다. 또한 최근 들어 FSW (Friction Stir Welding, FSW)기술이 발전함에 따라 접합기술개발이 다양화되면서 FSW Tool의 고성능의 초경 재료가 요구되어지며 장수명의 Tool개발이 되어야 한다. 국내에서는 초경 합금 재료로 사용되어지고 있는 텅스텐 카바이드(WC)와 코발트(Co)를 이용하여 많은 연구가 진행되었다. 본 실험에서는 텅스텐 카바이드와 코발트 및 몰르브덴 카바이드를 혼합하여 소결체를 제조하였다. 실험에 사용된 텅스텐 카바이드는 높은 경도를 가지고 강한 취성을 나타내며, 소결에 어려운 단점이 있다. 이러한 단점을 코발트와 몰리브덴 카바이드를 첨가하여 소결온도를 낮춰주는 역할과 액상 소결시 텅스텐카바이드 입자사이에 침투하여 액상소결에 의한 치밀화가 가능하게 해주며 인성이 향상되어 고인성 재료를 만들 수 있었다. 본 실험에서는 합성과 치밀화가 동시에 진행되는 SPS (Spark Plasma Sintering:SPS) 장비를 이용하여 실험을 진행하였다. 이 방법은 방전플라즈마 소결 공법으로, 기존의 연소법과 열간 가압기술(Hot-press, HIP)을 결합한 방식으로 단 시간, 단일공정으로 치밀한 소결체를 얻을 수 있는 장점이 있다. 본 연구에서는 $WC-5Mo_2C$-5wt%Co 소결체 제조를 위해 원소 분말을 Horizontal ball milling 혼합하였다. 균일하게 혼합된 분말을 흑연다이에 충진하여 펄스전류와 기계적 압력을 동시에 가하여 $WC-5Mo_2C-5Co$ 복합재료를 제조하고 소결체의 밀도, 순도, 상변태, 미세조직 등을 분석 및 평가하였다. SPS공정 조건은 고진공하에서 $1,200^{\circ}C$-60MPa, 펄스비 12:1 조건으로 수행하였으며, 얻어진 $WC-5Mo_2C-5Co$ 소결체의 상대 밀도는 98%이상 이였다. 또한, 결정립 크기는 약 400 nm였으며, 경도는 $2,453kg/mm^2$를 나타내었다.

• Journal of Energy Engineering
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• v.10 no.4
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• pp.349-356
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• 2001

Phenomenon of direct contact condensation (DCC) heat transfer between steam and water is characterized by the transport of heat and mass through a moving steam/water interface. Since the DCC heat transfer provides some advantageous features in the viewpoint of enhanced heat transfer, it is widely applied to the diversified industries. This study proposes a simple condensation model on the stable steam jets discharging into a quenching tank with subcooled water from a single horizontal pipe for the prediction of the steam jet shapes. The model was derived from the mass, momentum and energy equations as well as thermal balance equation with condensing characteristics at the steam/water interface for the axi-symmetric coordinates. The extremely large heat transfer rate at the steam/water interface was reflected in the effective thermal conductivity estimated from the previous experimental results. The results were compared with the experimental ones. The predicted steam jet shape(i. e. radius and length) by the model was increasing as the steam mass flux and the pool temperature were increasing, which was similar to the trend observed in the experiment.

• International Commerce and Information Review
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• v.13 no.3
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• pp.489-510
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• 2011

Free Trade Agreement (FTA) between the Korea, of the one part, and the EU and its member states, of the other part, has been effective, as of 1 Jul 2011. EU enlarged its members up to 27 countries including Romania and Bulgaria in 2007, and stood up as the second largest trading partner to the Korea right after the China. FTA, generally, shows the several different figures according to the countries concerned on the agreement The EU has long history and cultural, educational assets. In addition to that, the EU also has economical, industrial bases. Therefore, the EU seeks fruitful profits utilizing its intellectual property rights. There are copyrights and related rights, trade marks, geographical indications, designs, and patents, etc. on the Chapter 10. intellectual property rights of the Korea EU FTA. Among them, the others except geographical indications seem to be somewhat the terms advantageous to the Korea. It is possible to ask further requirements to the Korea in the years to come because the EU member countries are very much interested in the practical profits of intellectual property rights. Thus, it would be essential tasks for us to review the intellectual property rights protection and features of the Korea EU FTA.

• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.41-46
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• 2012

The flash point the lowest temperature at which the concentration of vapor of the substance in the air reaches the lower flammability limit(LFL), and is one of the most important physical properties used to determine the potential for fire and explosion hazards of industrial materials. The most published flash point data was for pure components and the flash points of the binary solutions that have flammable components, appear to be scarce in the literature. In the present study, the flash points of tert-pentanol+n-decane system were measured by Tag open-cup tester. The measured data were compared with the values calculated by the Raoult's law and the optimization methods based on the Wilson and NRTL equations. The calculated values by optimization methods were found to be better than those based on the Raoult's law.

• The Journal of Society for e-Business Studies
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• v.16 no.3
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• pp.145-158
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• 2011

Recently, the rapidly increased use of smartphone devices provides both opportunity and problems at the same time to the telecom companies in domestic and world wide. It provides a great opportunity to overcome the market stagnation of the existing voice- centric communications, and also problems of building a highly efficient new wireless access networks to accommodate huge volume of data traffic among smart devices. Facing with the age of keen competition, telecom companies have two kinds of strategies for network transition; a strategy of building uniform LTE -based 4G networks as fast as possible, and a hybrid network enhancement strategy compounding 3G and 4G networks using HSP A+, WiFi, cloud computing, etc. It is difficult to predict which strategy will have more successful outcome in the near future. This paper studies the trends and issues of network enhancement policies and transition strategies to the 4G network era, and tries to draw appropriate and efficient ways for network enhancement and operation.