• Journal of the Society of Naval Architects of Korea
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• 제53권1호
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• pp.62-68
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• 2016

A simple calculation tool for added resistance in waves is developed to utilize for initial design or embedded module for navigation support system. In order to select an appropriate calculation method for added resistance in waves, three methods (drift method, integrated pressure method, radiated energy method) based on strip method are applied to Wigley I and KVLCC2. The methods for added resistance in waves give the underestimated results because it is difficult to consider nonlinear effects due to reflected wave. We apply asymptotic (Faltinsen's method) and empirical formula (NMRI's method) to improve the accuracy for short wave length region. In comparison with experimental results, the combination of radiated energy method and short wave correction method of NMRI is the most reasonable. However, a simple sum of results calculated by two methods gives rise to the overestimation of added resistance for short wave length region because added resistance of radiated energy method exits in total reflection region. To overcome this problem, modified radiated energy method is proposed using correction coefficient defined by reflection coefficient of NMRI's method. Finally, added resistance in regular waves is composed of added resistance of modified radiated energy method and that of short wave correction method of NMRI. Estimated added resistance in regular waves is validated by comparison with experimental results of other research groups.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.57.2-57.2
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• 2011

Dye-sensitized solar cells (DSSC) have recently been developed as a cost-effective photovoltaic system due to their low-cost materials and facile processing. The production of DSSC involves chemical and thermal processes but no vacuum is involved. Therefore, DSSC can be fabricated without using expensive equipment. The use of dyes and nanocrystalline $TiO_2$ is one of the most promising approaches to realize both high performance and low cost. The efficiency of the DSSC changes consequently in the particle size, morphology, crystallization and surface state of the $TiO_2$. Nanocrystalline $TiO_2$ materials have been widely used as a photo catalyst and an electron collector in DSSC. Front electrode in DSSC are required to have an extremely high porosity and surface area such that the dyes can be sufficiently adsorbed and be electronically interconnected, resulting in the efficient generation of photocurrent within cells. In this study, DSSC were fabricated by an screen printing for the $TiO_2$ thin film. $TiO_2$ nanoparticles characterized by X-ray diffractometer (XRD) and scanning electron microscope (SEM) and scanning auger microscopy (SAM) and zeta potential and electrochemical impedance spectroscopy(EIS).In addition, DSSC module was modeled and simulated using the SILVACO TCAD software program. Improve the efficiency of DSSC, the effect of $TiO_2$ thin film thickness and $TiO_2$ nanoparticle size was investigated by SILVACO TCAD software program.

• Journal of KIISE:Computing Practices and Letters
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• 제5권4호
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• pp.489-497
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• 1999

국내의 ATM 기술은 대부분 교환기 시스템 개발에 집중되어 있었고 최근에는ATM 서비스 분야에 대한 개발 요구가 있다. 이러한 가운데 Internet 서비스는 데이타 망의 기본 서비스로 자리잡았으며, ATM망도 기본적으로 Internet 서비스를 지원하여야 한다. IETF의 IPOA (Classical IP and ARP over ATM)는 국내 망 여건 및 구현의 용이성으로 Internet 서비스를 위한 프로토콜중 가장 선호 대상이지만 RFC사양의 허술함, 구현자의 사양에 대한 이해 부족과 초기 외산 장비 제조 업체들의 자체 사양때문에 기존의 IPOA장비들과 상호 운용 시험에서 후발 IPOA 개발자는 시행착오를 겪어야만 한다. 본 논문에서는 기존 외산 IPOA 장비들과 자체 개발한 장비와 상호 운용 시험을 수행하면서 겪은 사례 연구를 정리하였고 이를 기초로 기존의 외산 IPOA와 상호 운용할 수 있는 최종 요구 사항을 제시하였다. 본 논문을 기초로 IPOA 장비를 개발한다면 국내 후발 ATM 장비 업체는 개발의 시간 및 노력을 줄일 수 있고 향후 IP/ATM 국내 기술력 향상에 도움이 될 것이다.Abstract While we have been focusing on development of ATM switching systems, recently the demand on service by use of ATM switching system is increasing rapidly. Among various ATM services, the Internet service should be provided in an ATM network since the Internet service has been the basic data service. Many domestic engineers consider the classical IP and ARP over ATM (IPOA) to be an appropriate method for interworking of IP and ATM because the IP is the network protocol used in most domestic data networks, and the IPOA is simpler and has less overhead than other approaches. However, it is not easy for a developer to implement the IPOA function module interoperable with other existing ones due to the incomplete description of IETF's RFC specifications, misunderstanding of designer and/or developer, and incompatible vendors' specifications. In this paper, we show several case studies undertaken for interoperability tests of IPOA products between our product and other vendor's products, and discuss the implementation requirement of the IPOA software to be interoperable with the existing IPOA equipment.The design and implementation requirements presented in this paper will reduce the effort of IPOA-developing engineers and time required for interoperability test. Also, this contribution will be helpful in IP/ATM interworking areas.

• Proceedings of the KAIS Fall Conference
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• 한국산학기술학회 2010년도 춘계학술발표논문집 2부
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• pp.610-613
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• 2010

본 과제를 통하여 기술적으로는 로봇 개발에 있어 기존 기술을 최대한 활용하고 새로운 기능을 추가하는 형태로 발전해 갈 수 있도록, 각 요소별 기능을 표준화 모듈화 하여 새로운 제품의 개발이 손쉽게 이루어 질 수 있는 기본 platform으로의 역할이 가능해졌다. 구동부 제작 및 설계, 금형 비용 등을 절감하기 위한 다목적 완구로봇 플랫폼을 확보할 수 있었다. 로봇이 복잡한 환경을 인식하고, 자율적으로 작업을 수행하며, 예측하지 못한 문제에 적절한 대처를 할 수 있도록 하기 위한 핵심 기술을 제공하게 될 것으로 생각된다. 로봇 개발에 있어 전문지식이 없는 초보자들이 직접 제작 구동해 볼 수 있는 비주얼한 개발환경을 지원할 뿐만 아니라 GUI 개발환경 및 TEXT Programming 으로 상호 전환이 가능한 코딩 방법을 지원(MSRS와의 차별화를 시도하였다. 기존 하드웨어 지식과 소프트웨어지식이 없는 상태에서도 제작자의 창의력에 따라 다양한 형태의 로봇을 제작 적용이 용의 하며 초보자들에 대한 로봇개발에 흥미를 유발할 수 있도록 하였다. 고급사용자를 위한 별도의 다운로딩 포트를 제공하였다. 로봇공학의 기본지식을 습득(아날로그/디지털 회로를 이해하고, 각종 센서의 이해하며, 스템/서보/DC모터의 제어기술, 펌웨어개발능력, 기본수준의 소프트웨어개발 능력) 활용할 수 있다. 또한, 경제 및 산업적 측면으로는 다음과 같은 장점이 있다. 기존 기술들의 장점을 취합하여 추가적인 기술을 적용할 수 있는 Base형태의 로봇을 개발할 경우 이를 활용한 제품 개발 및 Base자체로도 충분한 시장을 형성 할 수 있을 것으로 기대된다. 인터넷기반 로봇 제어 기술의 확보로 로봇시스템의 생산비용을 낮추고 TTM (Time-to-Market) 제약을 해결시켜 준다. 다른 응용 시스템에 쉽게 적용이 가능하고 지식기반 로봇 서비스의 요소기술 개발은 멀티미디어 콘텐츠분야(교육/게임/오락 등)의 활성화가 가능하기 때문에 타 IT산업에의 파급효과가 예상된다. B2B를 통한 실질적인 판매를 통한 동종기업의 연구 개발비 및 개발 기간의 단축이 예상된다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제30권6호
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• pp.124-129
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• 2002

KAISTAT-4 is the fourth experimental microsatellite of KITSAT series which has been developed by Satellite Technology Research Center of KAIST for the last two years. The launch of KAISTSAT-4 is scheduled in 2003. The primary experimental payloads consist of Far-ultraviolet Imaging Spectrograph and Space Physis Package. In a similar way to KITSAT series, the interior of KAISTSAT-4 comprises mainly a set of stacked aluminium-alloy module boxes, each being capable of acting as the primary load path in the mechanical structure. The KAISTSAT-4 qualification model is now designed, fabricated, integrated, and tested to verify if the electrical and mechanical components work and can withstand the launch environments. All the required structural tests have been performed to a sufficient degree to satisfy the intent of the test requirements. This paper presents the structural system and launch environmental test results of KAISTSAT-4 qualification model.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제32권7호
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• pp.126-132
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• 2004

Thermal control of satellite propellant tank is achieved by patch heaters enabled by thermostat's behavior. It is important to attach the thermostat on the appropriate position of the propellant tank. However its position cannot be given with exact numerics because tank is spherical. In practice, the thermostat position is designated approximately in a relevant drawing approximately, thereby an engineer practices depending on his own experience and intuition. The sensitivity analysis for the position of thermostat is performed such that the influence on the thermal behavior and control of tank is examined quantatively. When assembling tank module, the reasonable performance on the thermal control is believed with possible human errors if the uncertainty in the position of thermostat is not quite large.

• Journal of Radiation Protection and Research
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• 제43권2호
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• pp.39-49
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• 2018

Background: A model to assess the activity concentration of agricultural products and the public ingestion dose as result of a nuclear accident is necessarily required to manage the contaminated agricultural systems by the accident, or to estimate the effects of chronic exposure due to food ingestion at a Level 3 PSA. Materials and Methods: A dynamic compartment model, which is composed of three sub-modules, namely, an agricultural plant contamination assessment model, an animal product contamination assessment model, and an ingestion dose assessment model has been developed based on Korean farming characteristics such as the growth characteristics of rice and stockbreeding. Results and Discussion: The application study showed that the present model can predict well the characteristics of the activity concentration for agricultural products and ingestion dose depending on the deposition date. Conclusion: The present model is very useful to predict the radioactivity concentration of agricultural foodstuffs and public ingestion dose as consequence of a nuclear accident. Consequently, it is expected to be used effectively as a module for the ingestion dose calculation of the Korean agricultural contamination management system as well as the Level 3 PSA code, which is currently being developed.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제23권4호
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• pp.997-1005
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• 1998

This paper presents a modified on-off algorithm based on the gradient method for providing the phase of each antenna element more accurately and simply compared to the conventional on-off algorithm. The sup4erisority of theproposed method is due to the fact that the proposed method finds the increase and decrease of the array output power more accurately by utilizing the gradient of array output power with respect to the instantaneous phase of array element. The array antenna adopting to the proposed method formsmaximum beam-pattern along the direction of the desired signal by aligning the phase of every antenna enement. The proposed method is applied to both linear and two-dimentional aray for analyzing the result. The capability of the real-time processing of the proposed technique is confirmed by implementing the proposed algorithm with TMS320C30 Evaluation Module. Since the computational load required to form the beam-pattern per snapshot is small, the proposed method is suitable for the mobile communication system of which the response must be fast. By the results obtained from the application of the proposed method to the CDMA mobile communication environment, it is vreified that the performance of the received signal is consideralbly improved.

• Journal of rehabilitation welfare engineering & assistive technology
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• 제8권3호
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• pp.151-160
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• 2014

In this study, the effect of the automotive haptic-seat technology which can transmit the driving information by the vibro-stimulus from the seat was investigated to overcome previous system's limitation relied on the visual and audial method and to help handicap driving. A prototype haptic seat cover with 30 coin-type motors and driver module were developed for this sake. In an experiment of seat vibration stimulation being performed under virtual driving situation by targeting the elderly aged over 65 years old, average score of test subjects for total vibration recognition was 3.5/4 points and recognition rate of 87.5% was represented. In addition, a result that all the test subjects totally recognized overspeed warning signal of 4 times was represented. As a result of statistical analysis for vibration recognition score by each group depending on TMT score, a significant difference was not found and a result that tactile function of which vibration is recognized even by the aged whose visual, perceptional function is declined showed an equal ability was obtained.. In this study it was shown that the seat vibration stimulus could be used to transfer the old drivers' information while driving.

• Journal of Digital Convergence
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• 제14권1호
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• pp.75-82
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• 2016

The most of public services that we use these days is distributed and supplied as 'App' service because of wide spread of smat phones. Especially, since the interest of general citizens about usabilitu of public data has been increased, in case of Seoul, people can reach the data through 'Seoul Open Data Plaza' of 25 regions of Seoul. It becomes possible to construct various throughout this system. Ultimately, in case of users, they are provided many services through their electronic media. Looking at the development and research of public data service, they are mostly focusing on service or building up the service, but the research on visualization of contents is insufficient. This study is suggesting the specific plan and directionality of building public service using the public data which studied in the advanced research, "The user interface platform". Finally. this research is for a right usage of public data in the smart urban environment in near future and providing the practical public service.