• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.571-576
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• 1994

In recent years, ultrasonic has been widely applied in measurement and industrial fields and its application range has been expanded as a result of continuous research and development. Wire Bonding Machine, an instrument fabricating semi-conductor, makes use of ultrasonic bonding method. In order to improve the currently used wire bonding machine using ultrasonic energy, technical accumulation is needed steadily through development of exciting device of ultrasonic composed of piezoelectic vibrator and horn. This study investigates the design conditions affecting the dynamic characteristics through the theoretical and experimental analysis of piezoelectric vibrator and horn, The study conducts separately the system identification of piezoelectric vibrator in time domain and the modal analysis of horn in frequency domain. In theoretical model, the integrated modeling is conducted via a combination of dynamic identification of piezoelectric vibrator and theoretical analysis of horn. Hence comparison is made for theoretical and experimental results of the dynamic characteristics of the ultrasonic transducer composed of piezoelectric vibrator and horn. Form the results of this study we develop the design technique of ultrasonic transducer using dynamic characteristic analysis and propose the possibility of ultrasonic welding considering the optimal condition of the natural frequency and vibration mode of horn.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.449-450
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• 2006

Development of a feed drive system with high speed, positioning accuracy and thrust has been an important issue in modern automation systems and machine tools. Linear motors can be used as an efficient system to achieve such technical demands. By eliminating mechanical transmission mechanisms such as ball screw or rack-pinion, much higher speeds and greater acceleration can be achieved without backlash or excessive friction. However, an important disadvantage of linear motor system is its high power loss and heating up of motor and neighboring machine components on operation. For the application of the linear motors to precision machine tools an effective cooling method and thermal optimizing measures are required. In this paper presents an investigation into a thermal behavior of linear motor cooling plate. FVM employed to analyze the thermal behavior of the linear motor cooling plate, using the ANSYS-CFX.

• Wind and Structures
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• 제15권5호
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• pp.409-421
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• 2012

In this paper, the method of introducing additional source/sink terms in the turbulence and momentum transport equations was applied to appropriately model the effect of the tree canopy. At first, the new additional source term for the turbulence frequency ${\omega}$ equation in the SST k-${\omega}$ model was proposed through theoretical analogy. Then the new source/sink term model for the SST k-${\omega}$ model was numerically verified. At last, the proposed source term model was adopted in the wind environment optimal design of the twin high-rise buildings of CABR (China Academy of Building Research). Based on the numerical simulations, the technical measure to ameliorate the wind environment was proposed. Using the new inflow boundary conditions developed in the previous studies, it was concluded that the theoretically reasonable source term model of the SST k-${\omega}$ model was applicable for modeling the tree canopy flow and accurate numerical results are obtained.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.924-926
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• 2006

저전력 집적회로 기술과 MEMS (micro electro-mechanical systems) 기술이 융합된 산물인 스마트 센서는 작은 크기, 저비용, 저전력의 특성을 가지고, 그와 더불어 임베디드 어플리케이션에 사용되기에 적합하므로 이동 환경 컴퓨팅 분야에서 주목을 받고 있다. 이 센서들이 이동 통신에 적용되면 어플리케이션의 특성에 따라 인간의 접촉이 쉽지 않은 곳과 원격 통신이 가능하다는 장점이 있다. 이러한 혁명적인 원격 네트워크 기술로 인하여 활동적인 연구자들에게 엄청난 연구의 장이 열린 것이다. 본 논문에서는 그 중 한가지의 어플리케이션인 열센서 카메라에 대한 응용 분야로, 적외선 열센서 카메라에 대한 미세 조정을 위한 시스템 구축 방안에 대하여 논의한다.

• Journal of Positioning, Navigation, and Timing
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• 제11권4호
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• pp.279-286
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• 2022

In this paper, we designed a software library that produces integrated Global Navigation Satellite System (GNSS) / Inertial Navigation System (INS) navigation information using the raw measurements provided by the GNSS chipset, gyroscope, accelerometer and magnetometer embedded in android smartphone. Loosely coupled integration method was used to derive information of GNSS /INS integrated navigation. An application built in the designed library was developed and installed on the android smartphone. And we conducted field experiments. GNSS navigation messages were collected in the Radio Technical Commission for Maritime Service (RTCM 3.0) format by the Network Transport of RTCM via Internet Protocol (NTRIP). As a result of experiments, it was confirmed that design requirements were satisfied by deriving navigation such as three-dimensional position and speed, course over ground (COG), speed over ground (SOG), heading and protection level (PL) using the designed library. In addition, the results of this experiment are expected to be applicable to maritime navigation applications using smart device.

• Educational Technology International
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• 제6권1호
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• pp.103-119
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• 2005

This study investigated to designand implement web-based collaborative learning system Co-Net and map out students' learning procedure using the system, based upon Student Team Achievement Division (STAD Slavin, 1990, 1996). There are technical process and instructional considerations to be made during the design process. The former are those that concern equipment requirements and specifications and include Ease of Use, Speed of Access, and Flexibility. On the other hand, instructional considerationsare concerned with the delivery and access of instructional materials and their outcomes on learners. They are cooperative interactions within groups and group heterogeneity, learner control, group incentives, individual accountability, equal opportunity for earning high scores and contributing to group effort, task specialization, and competition among groups. A web site for a virtual learning environment designed and built by the authors and known as Co-Net is then explained along with the whole process learners inside the environment. The main page of Co-Net consists of 15 menus to implement cooperative learning process. The cooperative learning activities using 15 menus are composed of six phases (1) preparation of the new knowledge (2) presentation of the new knowledge (3) knowledge assimilation and application (4) team and individual evaluation (5) team and individual recognition Throughout the five phases, the appropriate use of cooperative learning techniques has been shown to have both academic and social benefits to learners.

• 한국해양공학회지
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• 제28권1호
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• pp.77-84
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• 2014

Recently, CFRP composites have often been used as the materials for lightweight pleasure yacht hulls. Because CFRP composites not only make the hull light but also have good physical characteristics, in the leading countries of the marine industries, CFRP yachts are being sold at a higher price. The design and construction of FRP composite yachts, including those made of CFRP, have to follow rules based on ISO 12215, such as the hull structure rules of the international classification societies. On the other hand, there are no rules related to CFRP composites in the Guidance for Recreational Crafts, which was newly revised by the Korean Register of Shipping. In this paper, ISO 12215-5 and Part B, RINA Pleasure Yacht (REGISTRO ITALIANO NAVALE) on the design pressure and scantling of CFRP hull structures are compared and analyzed. Through a comparative study and the application to a cruise yacht design, we try to understand how to design CFRP hull structures using the international standards, ISO 12215, and the rules of the international classification society, RINA.

• 한국건설관리학회논문집
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• 제18권5호
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• pp.50-58
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• 2017

최종 설계 결과물의 완성도와 발주자 요구에 적합한 설계 품질을 확보하기 위해서 프로젝트 참여자간 요구사항의 공유와 원활한 커뮤니케이션 과정이 필요하다. 하지만 기존의 문서기반, 도면기반 협력 방식은 복잡한 설계도서의 효과적 이해가 어렵고, 해당 분야의 충분한 기술적 경험이 중요하다. 참여자간 커뮤니케이션의 비효과적, 비효율적인 전달과 이해는 기능의 간섭 및 충돌의 가능성을 높이고 사업 수행의 물질적, 시간적 손실을 초래한다. 따라서 본 연구는 국내 건축설계업무에서의 참여자간 커뮤니케이션 현황과 인식을 조사하고 개선 방향을 제안하고자한다. 설문조사 내용을 기반으로 커뮤니케이션 증진요건을 분석하고 QFD 도구를 이용하여 기술적 요구사항을 프로젝트 참여자간 공유하고 수정하고 피드백 할 수 있는 커뮤니케이션 방안을 제시한다. QFD는 통합적인 설계검토가 가능하여 기능 간섭 및 충돌과 같은 예상 문제점을 발견하고 공유할 수 있다. 본 연구는 QFD를 이용한 커뮤니케이션 도구를 통해 적합한 의사결정을 지원하며 결과적으로 사용자 만족도 향상을 목적으로 한다.

• 콘크리트학회논문집
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• 제29권3호
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• pp.259-266
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• 2017

본 연구는 PHC말뚝의 단점인 전단력을 보강한 기능성말뚝을 개발하여 보다 경제적이고 합리적인 말뚝의 현장 적용에 기여하고자 하였다. 본 연구를 통해 개발된 CFP말뚝은 링형 합성 전단연결재를 배치하고 PHC말뚝 중공부에 콘크리트를 속채움함으로써 말뚝의 전단성능을 증대시키고, PHC말뚝 내 보강철근(H13-8ea)과 말뚝 중공부의 보강철근(H19-8ea)을 배치하여 횡보강철근비 증대에 따른 전단강도를 향상시켰다. 또한, 속채움 콘크리트와 PHC말뚝의 합성거동을 위해 말뚝 보강철근의 정착 홀이 형성된 합성 전단연결재를 배치하여 보강철근의 다월력을 말뚝의 전단강도 증진에 효과적으로 반영시켰다. CFP말뚝의 전단설계와 성능을 검증하고자 도로교설계기준의 한계상태설계법(2012)을 적용한 전단강도를 산출하였고, 말뚝 시험규정인 KS F 4306에서 제시한 실험방법을 통해 결과값을 비교 검토하였다. CFP말뚝의 단면별 설계전단강도와 실험결과 각 시험체는 설계전단강도 대비 평균 2.20, 2.15, 2.05의 안전율을 확보하는 것으로 나타나 효과적인 전단강도 예측이 가능할 것으로 생각된다.

• KIEAE Journal
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• 제3권3호
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• pp.11-18
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• 2003

The purpose of this study was to find out awareness of the environment-friendly planning elements for residential unit space among practitioners. The respondents in this questionnaire survey were 140 practitioners in architecture and interior design field. The major findings of this study were as follows; most of the respondents were aware of the impact of indoor built environment on residents' wellness. In addition, the survey respondents viewed that the factors for planning environment-friendly high-rise apartments were represented by gardening and energy-saving while their perception on the concept excluded comprehensive components affecting residents' life quality. Over 50% of respondents had an experience of applying environment-friendly planning elements in their works, and high frequency appeared on the general planning elements which had been applied special awareness as pro-environmental features. The respondents considered environment-friendly planning elements as important. Specially, space planning and system were considered more likely important in interior design field. In application of environment-friendly planning elements, cost, lack of consumers' awareness of and underdevelopment of environment-friendly materials were of concern. Therefore, the consumer's cognition needs to be improved for wide application about environment-friendly planning element, and then consumers are willing to pay additional construction cost of environment-friendly apartments. At the same time, the current practice that housing developers pass the additional cost on to residents needs to be changed. Then, the quality of life in high-rise residential settings can be improved. More importantly, the exchange and development of the reliable information on environment-friendly planning elements need to be made, and technical support and long-term policy for the development are required. This research showed current status of knowledge and practice in sustainable planning of unit apartment and proved basic information for future direction.