• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.248-251
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• 2005

본 연구에서는 가스 터빈 엔진의 결함에 의해 나타나는 엔진의 성능 저하를 진단하는 기법을 연구하였다. 대상 엔진을 모델화하기 위해 상용 프로그램 GSP를 이용하여 저하된 성능 진단을 위한 변수들을 추출하였으며 이를 바탕으로 Health Monitoring을 위한 Virtual Sensor Model을 구축하였다. 단일 결함과 복합 결함을 예측하기 위한 방법으로 Multiple Linear Regression기법과 가중치를 이용한 기법을 도입하여 엔진 구성품의 결함 위치 및 결함 정도를 예측하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.241-243
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• 1996

This papar presents an analysing method of radial force densities acting on each stator tooth of an induction motor with skewed slots. Two-dimensional finite element method is used for electromagnetic Held analysis of an induction motor, and skew effects are considered by coupling several disks cut by planes perpendicular to the shaft. Radial force densities as a source of vibration are calculated along the surface elements of each stator tooth and its time harmonics are examined by discrete Fourier decomposition.

• Journal of Yeungnam Medical Science
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• 제5권2호
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• pp.235-238
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• 1988

저자들은 최근 약 5cm 길이의 근위부 맹관을 가진 불완전 종복요도를 발견하여 이의 완전 적출술을 시행하여 병리 검사상 편평 상피세포로 구성된 요도를 확인하였기에 문헌적 고찰과 함께 보고하는 바이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.733-735
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• 2001

The high temperature superconducting bulk can be used as the bearing of a motor. This paper presents the fabrication and test results of a motor with superconducting bearing using HTS bulks. The bearing used four hexahedron type YBCO bulks. Height, width and depth of the HTS bulk were 10mm, 30mm and 30mm, respectively. Single phase induction motor was used to drive the shaft and solid rotor was adopted for high speed rotation. Test results show the motor with HTS magnetic bearing can rotate silently and smoothly without any contact.

• 대한조선학회지
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• 제3권1호
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• pp.25-32
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• 1966

For preliminary estimation of ships' machinery weights, many papers giving well-judged data and discussions for rational method of estimation, such as [1], [2], [3], [4], [5], [6], are available, however, they are mostly concerned with large ships propelled by power more than about 2, 000 horsepower. Regarding the medium and small-sized ships, as far as the author is aware, fragmental data and vague discussions found in various technical literature are the all available. In this paper, available data concerned with machinery weights of commercial ships propelled by direct-drive diesel plants of power below 3, 000 horsepower with single screw propeller are collected and analysed to obtain systematic data Fig. 1 and Fig. 2 as weight to power ratio versus power per shaft diagrams together with suplementary data Fig. 1 and Fig. 3. Influences of various factor such as revolutions per minute, mean effective pressure, type and construction of the main units on machinery weights are also investigated in detail to give a better guidance for logical and rational utlization of the proposed diagrams in preliminary estimation of machinery weights.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.601-604
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• 1994

This paper describes an effective method to estimate a position of an automous vehicle equipped with a single CCD-camera along indoor passageways. Using the sequential image data from the self-movement of the vehicle, the position is estimated by integrating the approximated motion parameters. The detection of the yaw angle that is one of the motion parameter is difficult in general, e.g. slip or error for noise, therefore the different detection is presented, which is, without shaft encoders, based on a projection function for 2D-image data and a cross-correlation function so as to be robust for noise. The approximated geometric function to estimate the position is used to reduce the computational effort. To verify the effectiveness of the method, the analysis and the computational results are shown through the simulations. Furthermore, the experimental results by using the test vehicle for the real indoor passageway are shown.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.245-252
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• 2000

Model tests on free standing pile groups and piled footings with varying a pile spacing in two layered soils are carried out. The influence of pile cap on the behaviors of end bearing pile groups is analyzed by comparing the bearing behavior in piled footings with those in a single pile, a shallow footing(cap alone) and free standing pile groups. From the test results, it is found that the bearing characteristics of cap-soil-pile system are related with load levels and pile spacings. Before yield, the bearing resistance by cap is not fully mobilized, however, as the applied load increases, the bearing resistance of cap approaches to that of cap alone and settlement hardening occurs after yield due to the compaction caused by the contact pressure between cap and soil. By the cap-soil-pile interaction, shaft friction and point resistance of piles considerably increase with dependency of pile spacings. In two layered soil, the increasing effect of dilatancy in dense sandy soil adjacent to pile tips, increases the point resistance of pile.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.157-160
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• 2006

A turbo-expander is developed for the regeneration in the expansion process. The turbo-expander operates in the partial admission and supersonic flow, and an axial-type single stage turbine is applied to the turbo-expander. Its outer diameter is 82mm and the operating gas is R134a. A 15kW reciprocating compressor is applied in this experiment and the turbo-expander is installed in the expansion process instead of the commonly using expansion valve. Two supersonic nozzles are applied for the expansion process. The high speed of R 134a after passing the supersonic nozzles gives the impulse force to the turbo-expander and some powers are generated on this process. A generator is installed at the end of the turbo-expander shaft. The generating output power from the turbo-expander is controlled by the power controller. Pressures and temperatures are measured on the lines for the performance investigation. More than 600W/(kg/sec) are generated in this experiment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.662-667
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• 2000

A simulation procedure for a full transient analysis of the start-up of heavy-duty gas turbines for power generation is constructed. Compressor stages are grouped into three categories (front, mid, rear) and three different stage characteristic curves are applied to consider the different low-speed operating characteristics. Start-up behavior of a typical single-shaft gas turbine for power generation is simulated. The predicted transient behavior shows a good agreement with the field data. Special attention is paid to the effects of the modulation of VIGV on start-up characteristics, which play a key role in the stable operation of gas turbines.

• 대한기계학회논문집B
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• 제33권12호
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• pp.933-938
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• 2009

Hot test of a full-scale turbopump for a 30-ton-thrust liquid rocket engine was carried out. The turbopump is composed of an oxidizer pump, a fuel pump, and a turbine on a single shaft. Model fluid was used in the test, that is, hot air for the turbine and water for the pumps. The turbopump was operated stably at full speed for 120 seconds. In terms of performance characteristics of pumps and turbine, the results from the turbopump assembly test are compared with those from the turbopump component tests which were performed at about half of the design rotational speed.