• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.930-931
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• 2008

This study is on the development of a low cost inverter module with Power Factor Correction(PFC) circuit which satisfies the international harmonic current standard such as IEC61000-3-2. In this study, the performances of the PFC circuit applying a new control method are simulated and verified by Matlab/Simulink. Also, the inverter module with the designed PFC circuit is implemented and the experimental results for the module are presented. Finally, through an analysis for the results of the simulation and the experiment, the merits obtainable by applying the PFC circuit when designing an inverter module are discussed and presented.

• 대한기계학회논문집A
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• 제21권12호
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• pp.2172-2178
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• 1997

Development of diamond wheel with fine grains and multi-pore structures were newely attempted. Wheels, that are employed for ultra precision and high performance grinding of difficult-to materials such as tungsten carbide alloy using tool and die materials, must have both performances to remove tool marks efficiently and to contact elastically with curved surfaces. Diamond grains were bonded firmly by a melamine resin to prevent the decrease of machining efficiency due to grain sinking within the bond materials. Also, highly foamed structures were developed to increase the flexibility of the wheel, and to induce active self-sharpening by increasing contact pressure between the wheel and work surfaces. In this paper, melamine-bonded diamond wheels are trial manufactured, then the forming method of wheels are suggested, and the grinding characteristics of wheels are also illustrated.

• 대한의용생체공학회:의공학회지
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• 제11권1호
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• pp.141-146
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• 1990

A clinical workstation has been developed for the use in clinical ward. This system is connected to the Picture Archiving and Communication System previously installed. It provides the capabilities of image display, image processing, diagnostic report review, clinical lab data review and analytic diagrams presentation for the hospitalized patients in clinical ward. The performances of this system were evaluated during the 9 months. These results show typical aspects of clinical patterns in data transmissions, image studies and clinical lab data studies. These typical aspects should be counted in the further development of workstation for the clinical use.

• International Journal of Aeronautical and Space Sciences
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• 제6권1호
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• pp.61-70
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• 2005

The currently developed propulsion system(PS) is composed of propellant tank, valves, thrusters, interconnecting line assembly and thermal hardwares to prevent propellant freezing in the space environment. Comprehensive engineering analyses in the structure, thermal, flow and plume fields are performed to evaluate main design parameters and to verify their suitabilities concurrently at the design phase. The integrated PS has undergone a series of acceptance tests to verify workmanship, performance, and functionality prior to spacecraft level integration. After all the processes of assembly, integration and test are completed, the PS is integrated with the satellite bus system successfully. At present, the severe environmental tests have been carried out to evaluate functionality performances of satellite bus system. This paper summarizes an overall development process of monopropellant propulsion system for the attitude and orbit control of LEO(Low Earth Orbit) observation satellite from the design engineering up to the integration and test.

• 한국과학교육학회지
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• 제22권5호
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• pp.1071-1081
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• 2002

This article describes the status of science teacher education in Taiwan. The pre-service and in-service science teacher training system, institutes, curricula, programs, and evaluation on the institutes were briefly introduced. The differences before and after the 1996 reform of science teacher training system were compared. Finally, the attempts and efforts that have been done through the channels of research to promote science teachers' professional development were addressed. These efforts include the Case studies of exemplary science teachers' teaching performances, the development of licensure instruments for the certification of science teachers, the use of computers and distance education for supervising student teachers, the exploration of promoting science teachers' understanding about the nature of science, the exploration of promoting science teachers' pedagogical content knowledge, the exploration of promoting science teachers' ability of increasing effective student-teacher and student-student interactions, and the exploration of effective teaching strategies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2371-2373
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• 1999

This paper deals with the development, reliability, specification and performances of the ACSR inner corrosion detector system. It is designed to run on ACSR automatically and to inspect the corrosion of the line with on-line continuously. And it comprises a sensor a constant current source, a signal processing unit, a RF transmitter and receiver unit. Also separable encircling coil sensor is proposed in order to detect inner corrosion of the overhead ground wires. In conclusion, this detector can realize the nondestructive detecting of an ACSR inner corrosion.

• 산업경영시스템학회지
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• 제28권4호
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• pp.1-6
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• 2005

This study is to investigate empirically the turnover awareness of key member working in Research & Development Division in high technology electronic R&D institute. Through the analysis of 106 questionnaires and individual depth interview with key member who is evaluated as core researcher and developer in their working project or has good results in the last 2-3 years, this study obtains the practical informations on the understandings of their professional consciousness and extend of turnover awareness etc. The findings are as follows. Two-thirds of the researcher has the mind of turnover to improve job stability and develop their career. They have an self-awareness that they are key member as a core competent person in working project and their organization, but are dissatisfied with the underestimation of their performances that are not recognized by the organization as they expected level. And the result indicates that many of them haven't find their visions in their organization.

• 전자통신동향분석
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• 제32권6호
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• pp.17-26
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• 2017

Electronic packaging technology is a technology that easily connects devices to the outside. The fourth industrial revolution is thought to be possible with the advancement of certain devices. The advancement of these devices must be accompanied by innovations in electronic packaging that connects the devices to the outside world, allowing their performances to be implemented at the system level. In this paper, the development trends of 2.5D/3D technology, heterogeneous integration technology, ultrafine interconnection technology, and heat dissipation technology will be examined, and the development direction of these technologies will be discussed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.597-598
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• 2006

This paper describes a development of a new $1.4{\times}1.1$ and $2.0{\times}1.4mm$ RF SAW filters made by PCB substrate instead of HTCC package, and this technology can reduce the cost of materials down to 40%. We have investigated the multi-layered PCB substrate structures and raw materials to find out the optimal flip-bonding condition between the $LiTaO_3$ wafer and PCB substrates. Also the optimal materials and processing conditions of epoxy laminating film were found out through the experiments which can reduce the bending moment caused by the difference of the thermal expansion between the PCB substrate and laminating film. The new PCB SAW filter shows good electrical and reliability performances with respect to the present SAW filters.

• 한국해양공학회지
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• 제18권1호
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• pp.80-84
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• 2004

The initial hull form of a 3 G/T and 30 knots class coastal leisure boat is newly developed. The performances measured, resistance, trim and sinkage, are investigated in a high-speed, circulating water channel (CWC). The effect of a fin attached on the hull side is studied together. Wave patterns are observed to clarify the relationship between the resistance performance and the wave characteristics. It can be found that the fin plays a role of increasing the resistance performance above a certain velocity.