• 한국유체기계학회 논문집
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• 제7권5호
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• pp.43-49
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• 2004

A turbo blower, driven by a high-speed blushless DC motor, was designed as a efficient substitute of a ring blower or a roots blower. Computational analysis and performance tests have been performed to investigate performance characteristics of the blower. Experimental measurements showed that the blower has a good stability margin. This paper gives an outline of design, computational flow analysis and performance test for aerodynamic evaluation of the variable speed turboblower.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.962-964
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• 2004

The plunger speed of solenoid actuator is affected by mass of plunger, magnetic motive force, inductance, and return spring. These factors are not independent but related with each other according to design characteristics of solenoid actuator. So, it is impossible to change the designed value for the purpose of increasing plunger speed. In this study, we have analyzed the characteristics of high-speed solenoid actuator having a non-magnetic ring which plays a role to concentrate the effective magnetic flux into plunger. For more detailed analysis, we have induced characteristic equations and performed FEM analysis and simulation for dynamic characteristics of plunger, and proved the propriety of these by experiments.

• 한국운동역학회지
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• 제17권3호
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• pp.217-224
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• 2007

This study was to investigate the effects of enslaving on finger-tip force of other fingers on finger pressing speed. We hypothesized that the effects depend on finger pressing speed, and the fingers proximity and are larger for fingers that are closer to each other. Six healthy, right-handed subjects(age: $27.1{\pm}4.3yr$, height: $175.4{\pm}7.2cm$, weight $71.3{\pm}5.8kg$) participated in the experiment. Each finger showed no significant on task finger speed. In the tasks with two neighboring fingers (e.g. middle and ring finger tasks), the index and middle fingers showed larger forces than the other neighboring fingers. During the index and little finger tasks, the enslaving force magnitude decreased with distance to the task finger (i.e. index finger enslaving force was the smallest during the little finger task).

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.360-366
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• 2001

This paper show the designing, manufacturing and performance test procedure of a high speed, fixed ratio planetary roller type traction drive as a speed reducer. The arrangement and size design for sun roller, planetary rollers and ring roller are carried out and a proper pre-load mechanism are adopted. To improve transmitting power capacity and endurance limit, nitro-carburized bearing steel and a synthetic traction oil are used. The manufactured and assembled traction drive operated successfully under unloaded conditions. Further tests for various load and speed conditions are executing now to improve the performance of the traction drive.

• 대한임베디드공학회논문지
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• 제16권6호
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• pp.247-251
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• 2021

We propose a protocol for Ethernet-based industrial real-time communication networks. In the protocol, the master periodically transmits control frames to all slaves, and the ring-type network topology is selected to achieve high-speed transmission speed. The proposed protocol is implemented in the form of both firmware and Linux kernel modules. To improve the transmission speed, the MAC address table is disabled in the firmware implementation, and the NAPI function of the Ethernet driver is removed in the Linux kernel module implementation. A network experiment environment is built with four ARM processor-based embedded systems and network operation experiments are performed for various frame sizes. From the experimental results, it is verified that the proposed protocol normally operates, and the firmware implementation shows better transmission speed than the Linux kernel module implementation.

• Tribology and Lubricants
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• 제21권5호
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• pp.201-208
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• 2005

This paper presents the FEM analysis on the contact behavior characteristics of mechanical face seals in a small hydro-power turbine. Especially, the axial displacement and contact normal stress between a seal ring and a seal seat of a primary sealing unit have been analyzed as functions of rotating speed of a hydro-turbine, sealing gap, water and cooling fluid temperature. Those are strongly related to a leakage of water and wear between a seal ring and a seal seat. The FEM computed results present that the rotating speed of a hydro-turbine may be kept less than 800 rpm, and the sealing gap in a primary sealing unit is restricted $0.5\~5$. The coolant temperature in which is most influential parameter to the contact behaviors of a sealing unit may be kept less than $15^{\circ}C$ for a safe operation of a sealing unit without a leakage and wear.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1724-1729
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• 1991

This paper gives an overview of HIGIPS design concepts and prototype HIGIPS configuration, and discusses its application to recognition of the 3-D motion of a human arm. HIGIPS which employs the combination of pipeline architecture and multiprocessor architecture, is a high-speed, high-performance and low cost N * M multimicroprocessor parallel machine, where N is the number of pipeline stages and M is the number of processors in each stage. The algorithm to recognize the motion of a human arm with a single TV camera was developed on personal computer (NEC PC9801 series). As a constraint condition, some simple ring marks are used. Each joint of the arm is attached with a ring mark to obtain its centroid position when the arm moves. These centroid positions in the three-dimensional space are linked at each of the successive pictures of the moving arm to recover its overall motion. This algorithm takes about 2 seconds to process one image frame on the general-purpose personal computer. This paper mainly discuses how to partition this algorithm and execute on HIGIPS, and shows the speed up. From this application, it is clear that HIGIPS is an efficient machine for image processing and recognizing.

• 한국전기전자재료학회논문지
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• 제16권6호
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• pp.484-489
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• 2003

In this paper, a single phase driven piezoelectric motor design was presented for linear motion Two metal/ceramic composite actuators, a piezoelectric ring which was bonded to a metal endcap from one side, were used as the active elements of this motor. The motor was composed of a piezoelectric ceramic, a metal ring which has 4 arms, and a guider. Motors with 30 [mm] and 35 [mm] diameter were studied by finite element analysis and experiments. As results, the maximum speed of motor was obtained at resonance frequency. When the applied voltage of the motor increased, the speed was increased. Also, bidirectional motion of the motor was achieved by combining two motors which have different resonance frequency. But the characteristics of bidirectional motion were not equaled, because of the problem of reproduction on the fabrication and the experiment. If present motor is used at the auto-zoom device of a camera, it will have much advantage. Because the direct linear motion can be achieved with a simple structure of motor and no gearbox of total system.

• 한국전자통신학회논문지
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• 제12권1호
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• pp.75-84
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• 2017

초고속 환경에서 대용량 데이터에 대한 안정적 기록 및 효율적인 데이터 접근의 필요성은 갈수록 높아지고 있다. 이와 관련된 기초과학의 한 분야로 방대한 천체 관측 데이터를 생산하는 VLBI(: Very Long Baseline Interferometer)가 있는데 고분해능, 고감도 관측 연구를 수행하기 위해서는 고성능의 데이터 저장 시스템이 요구된다. 하지만 시장에 출시된 대다수 클라우드 기반 스토리지는 일반 IT, 금융, 행정 서비스 지원을 위한 저용량, 복수 스트림의 비정형 데이터에 최적화되어 있기 때문에 빅 스트림 데이터 기록을 위한 최적의 대안이 될 수 없다. 본 논문에서는 이를 극복하기 위한 방안으로 데이터 입출력 처리에 있어 고성능, 동시성에 최적화된 데이터 저장 시스템을 설계하고자 한다. 이를 위해 멀티 코어 CPU 환경에서 libpcap, pf_ring 등의 API 호출을 통해 패킷 입출력 모듈을 구현하였고 외부로부터 유입되는 데이터를 효율적으로 처리할 수 있도록 소프트웨어 RAID(: Redundant Array of Inexpensive Disks) 기반의 확장성 있는 스토리지를 구축하였다.

• 한국통신학회논문지
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• 제19권7호
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• pp.1256-1271
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• 1994

본 논문에서는 Gbit 매체접근데어 프로토콜인 HMR(High-speed Multimedia Ring)의 퀘타 할당방법을 변형 적용하여 B-ISDN의 GFC(Generic Flow Control) 프로토콜로 제안하고 시뮬레이션을 통하여 제안된 프로토콜의 성능을 분석하였다. HMR 프로토콜은 Gbit ATM-LAN으로 제안되었지만 버스, 링, 스타버스 형태의 토폴로지에 적용할 수 있도록 고려되었을뿐 아니라 멀티미디어 트래픽 수용을 위한 다단계의 우선순위 제어기능을 가지고 있으므로 수정없이 GFC 프로토콜로 적용이 가능하다. 그러나 기존의 HMR 프로토콜에서 제안되었던 정적퀘타할당 방법은 버스트성이 큰 트래픽에 대하여는 엑세스지연이 과다하게 되는 단점이 있었다. 따라서 본 논문에서는 큐의 크기를 고려한 동적퀘타할당 방식을 적용한 HMR 프로토콜을 제안하고 CCITT에서 제안한 7사지 GFC 시험절차를 적용하여 시뮬레이션을 수행하였다. 동적 퀘타할당 방식을 적용한 HMR 프로토콜은 정적퀘타할당 방식을 적용한 HMR에 비하여 개선된 성능을 나타내었다. 또한 HMR-GFC 프로토콜은 ATMR에 비하여 우수한 성능을 나타내며, DQDB와는 대등한 정도의 성능을 나타탬을 확인하였다.