• Proceeding of EDISON Challenge
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• 2016.11a
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• pp.1-3
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• 2016

대형 화물 트럭(heavy-duty truck)은 화물 적재에 용이하지만, 공기역학적으로 불리한 형상을 가진다. 이러한 단점을 극복하고자 대형 화물 트럭에는 공기저항력(aerodynamic drag)을 줄일 수 있는 여러 가지 장치가 달려있다. 본 논문에서는 디플렉터(deflector) 형상이 항력 감소에 어떠한 영향을 주며, 평판 형태와 굴곡진 형태의 디플렉터 형상에 대한 항력 계수 비교를 EDISON-CFD를 활용하여 비교하였다. 해석 결과, 측풍(side-wind)의 영향을 무시하며 차량 속도 95 km/h로 등속을 유지하는 조건에서 평판 형태의 Model 1과 바깥으로 굴곡진 Model 2에서 전체 항력 계수가 낮게 나타났다.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.4
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• pp.274-280
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• 2007

This paper demonstrates an efficiency improvement of the class E power amplifier (PA) by tuning-out the input capacitance ($C_{IN}$) of the power HBT with a shunt inductance. In order to obtain high output power, the PA needs the large emitter size of a transistor. The larger the emitter size, the higher the parasitic capacitance. The parasitic $C_{IN}$ affects the distortion of the voltage signal at the base node and changes the duty cycle to decrease the PA's efficiency. Adopting the L-C resonance, we obtain a remarkable efficiency improvement of as much as 7%. This PA exhibits output power of 29 dBm and collector efficiency of 71% at 1.9 GHz.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.122-128
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• 2010

Efficient energy management is a very important issue in wireless sensor network since wireless sensor nodes are usually battery-powered. Recently, S-MAC protocol based on low duty-cycle has been proposed to reduce energy consumption. Even though research effort has been made to evaluate performance of S-MAC by conducting various simulations, however, some important simulation parameters are not well evaluated yet. In this paper, we identify the performance of S-MAC under different amount of streams and different patterns such as data rate and traffic. Through analyzing the simulation results, we discover weakness of S-MAC as well as analyze impact of amount of streams and packet pattern.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.173-174
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• 2012

본 논문에서는 전기자동차용 부하 직렬 공진형 컨버터(Series-loaded Resonant Converter, SRC)타입의 탑재형 충전기 (On-Board Charger, OBC)의 추가 회로 없이 경부하 효율을 향상시키기 위한 스위칭 방법들을 비교 분석한다. 시스템에 적용할 스위칭 제어 방법은 Asymmetrical Duty Cycle Control (ADC)과 Asymmetrical Voltage-Cancellation Control (AVC) 방법이다. 각 제어 방법을 기존의 3.3kW SRC-OBC의 적용하여 경부하 영역에서의 효율을 확인하고 각 제어 방법의 타당성을 검증한다.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.4
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• pp.57-66
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• 2011

We implemented the document DRM applying role based access control(RBAC) mechanism for preventing the information leakage of a document which is transmitted in network environment. It must prevent to access document not related to user role and duty, and must allow operation to document for improving security, considering user role and security level according to a document importance. We improved the security of document DRM by adding to the access control module applying RBAC for satisfying security requirements. Though the user access document, our system allows operation authorizations to document by the user's role & security level and the security attribute of RBAC. Our system prevents indiscriminate access to the documents by user who is not associated with the role, and prevents damage the confidentiality and integrity.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.171-172
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• 2012

본 논문에서는 Cascade buck-boost 컨버터 토폴로지에서 인덕터 전류 리플 손실을 감소시켜 효율 향상시키는 최적 스위칭 방법을 제시한다. 효율을 높이기 위한 최적 스위칭 방법은 다양한 방식으로 듀티크기와 위상을 변화시켜 인덕터 전류 리플로 인해 발생하는 손실을 비교하여 최소화하는 방식을 채택한다. 또한, 제시된 방법은 100W급 Test bed를 통해 타당성을 검증한다.

• Journal of the Korea Society of Computer and Information
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• v.21 no.12
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• pp.107-114
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• 2016

Web system helps high-performance processing for big-data analysis and practical use to make various information using IT resources. The government have started the RPS system in 2012. The system invigorates the electricity production as using renewable energy equipment. The government operates system gathered big-data with various related information system data and the system users are distributed geographically. The companies have to fulfill the system, are available to purchase the REC to other electricity generation company sellers to procure REC for their duty volumes. The REC market operates single auction methods with users a competitive price. But the price have the large variation with various user trading strategy and sellers situations. This papler proposed RPS system modeling and simulation in web environment that is modeled in geographically distributed computing environment for web user with DEVS W/S. Web simulation system base on web service helps to analysis correlation and variables that act on trading price and volume within RPS big-data and the analysis can be forecast REC price.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.4 no.1
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• pp.8-24
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• 1979

Including the Qualfication of Staffer required for Commuinication, the National Law of Professional qualification is a basic law for supply with manpower of high growth industry, and it is aiming at perfect the national Policy Concerned improvement for education and training of staff, carrying out of state examination for qualification and getting an occupation or application for special qualification. This law has established a management committee for qualification system in The Ministry of Science and Technique ROK, and authorized competence Minister according to kind of special qualification aiming at getting employment, practical use and courteous treatment in society and economy for national qualification, and also regulated their each official duty. A qualification of staffer required for communication is an administrative measure giving as occupational certificate after some examination for knowledge, technique and faculty in vocational ability to adapt to intrinsic of telecommunication. This certificate has the cause of an attribution of over the sphere of telecommunication, and so it has been originated in international situation, and then some of them is forced by international law, otherwise it be in common use between the nations. The Characteristic and orthodox of communication certificate has been succeded continually in company with development of telecommunication and the appliable field of them is specified, but the sovereign power of nation is approved by ITU that she can extent the applicable position for communication certificate and coordinate the utility of qualification for telecommunication value. Korean telecommunication law excepted the application of communication certificate in public communication field. It is unreasonable and even disobeyed against the theory of communication science and intrinsic of telecommuncation. Therefore it should be corrected immediately and then communication certificate have to accept in the public communication field at all, if so, the application field of communication certificate can have more than useful extenxion such as administration measure should be achieved by the management committee for qualification system in Ministry of Science and Technique and competemce Minister appointed according to special kind of certificate and the administration have to manage by the method and proccess caused by communication science or cooperative system between administration, industry, education and science. And, then, every acquisitor of qualification also has to try to perfect his vocational duty sincerely and to promote each self-realization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.221-224
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• 2012

This paper presents a CMOS interface circuit for MEMS acceleration sensor. It consists of a capacitance to voltage converter(CVC), a second-order switched-capacitor (SC) integrator and comparator. A bandgap reference(BGR) has been designed to supply a stable bias to the circuit and a ${\Sigma}{\Delta}$ Modulator with chopper - stabilization(CHS) has also been designed for more suppression of the low frequency noise and offset. As a result, the output of this ${\Sigma}{\Delta}$ Modulator increases about 10% duty cycle when the input voltage amplitude increases 100mV and the sensitivity is x, y-axis 0.45v/g, z-axis 0.28V/g. This work is designed and implemented in a 0.35um CMOS technology with a supply voltage of 3.3V and a sampling frequency of 3MHz sampling frequency. The size of the designed chip including PADs is $0.96mm{\times}0.85mm$.

• International Commerce and Information Review
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• v.17 no.3
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• pp.203-222
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• 2015

Papers in FTA research have mostly focused on the legal interpretation of the FTA treaties. In this research, more focus was put on the customs laws and related cases delivered in the U.S. federal courts, by which we can analyze the Korea-U.S. FTA in more practical manner to derive the enterprises' solutions to cope with the disputes of FTA preferential duty. The Tariff Act of 1930 is the U.S. customs law to govern FTA preferential duties. The administrative practices with customs duties are coordinated with the FTA rules. The most controversial issue in the U.S. customs law lies in the classification of imported goods for imposition of the customs duties, based on Harmonized Tariff Schedule of the United States. It was found that the U.S. federal courts had been quite favorable to the CBP(U.S. Customs and Border Protections) in litigation with the private importers and exporters. The reason seems to be that the CBP has been dealing with the customs cases so many times, accumulating much experience in execution of the U.S. customs laws, which is likely to make their decisions on customs duties almost free of errors. Therefore, the Korean exporters need to collect the CBP's past cases on the denial of preferential treatment on imported goods and be fully informed of the CBP's policies on the FTA preferential duty treatment.