• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.939-944
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• 1991

The dynamic behavior of a quick-acting hydraulic fuse is investigated by analysis and experiment. In view of the short response time, a proper dynamic analysis of the entire hydraulic circuit is necessary, in addition to analysis of the fuse behavior. Dynamic models of the fuse and other hydraulic circuit elements used in the experimental setup are derived and used for computer simulation. Also, the experiments are performed under a variety of operating conditions. Experimental and analytical results are in very good agreement.

• 전자공학회논문지CI
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• 제45권5호
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• pp.117-124
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• 2008

본 논문은 BcN(Broadband convergence Network)에서 IMS(IP Multimedia Subsystem)기반 멀티미디어 서비스를 제공함에 있어 세션 제어를 담당하는 CSCF(Call Session Control Function)의 호 처리 성능을 분석한 것이다. 지금까지 SIP기반의 음성 서비스의 호/세션 관련된 성능분석은 연구되고 있으나 IMS기반 멀티미디어 서비스의 호 처리 성능 분석에 대한 연구는 미흡한 실정이다. 본 논문에서는 M/M/1을 적용한 큐잉 모델과 OPNET 시뮬레이션을 통해 CSCF의 처리 용량과 가입자 수를 변화시키면서 IMS의 세션 설정 절차에 따른 호 설정 지연 시간을 측정하였다. 그 결과 총 사용자의 세션 설정 요구율이 CSCF 처리 용량의 13%이상일 경우에는 급격한 지연 증가가 나타남을 알 수 있었다. 따라서 본 성능 분석을 통해 세션 설정 지연 허용값에 맞는 CSCF의 용량과 가능한 사용자 수를 계산할 수 있을 것이다.

• Smart Structures and Systems
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• 제25권3호
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• pp.279-284
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• 2020

Electrical current is usually used to change the damping force of Magnetorheological Dampers (MRDs). However, changing the electrical current could shift the stiffness of the system, the phenomenon that was not considered carefully. This study aims to evaluate this shift. A typical MRD was designed, optimized, and fabricated to do some accurate and detailed experimental tests to examine the stiffness variation. The damper is equipped with a circulating system to prevent the deposition of particles when it is at rest. Besides that, a vibration setup was developed for the experimental study. It is capable of generating vibration with either constant frequency or frequency sweep and measure the amplitude of vibration. The damper was tested by the vibrating setup, and it was concluded that with a change in electrical current from 0 to 1.4 A, resonant frequency would change from 13.8 Hz to 16 Hz. Considering the unchanging mass of 85.1 kg, the change in resonant frequency translates as a shift in stiffness, which changes from 640 kN/m to 860 kN/m.

• 한국경영과학회지
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• 제13권1호
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• pp.13-13
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• 1988

This paper considers the sequencing problem in mixed model assembly lines with hybrid workstation types and sequence-dependent setup times. Computation time is often a critical factor in choosing a method of determining the sequence. We develop a mathematical formulation of the problem to minimize the overall length of a line, and present a tabu search technique which can provide a near optimal solution in real time. The proposed technique is compared with a genetic algorithm and a branch-and-bound method. Experimental results are reported to demonstrate the efficiency of the technique.

• 한국초전도ㆍ저온공학회논문지
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• 제1권2호
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• pp.30-36
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• 1999

Superconductors are dissipative when exposed to time-varying magnetic fields. To analyze the AC characteristics of a superconductor, one usually needs to know magnetization curves of it. Good magnetization curves can be obtained only in homogeneous magnetic filed. In This paper, we report the setup and test results of a magnetization measurement system, which consists mainly of frequency-variable power supply and homeogenous magnet with 7-cm long air gap. Special emphasis are foused on the design and fabrication of the magnet, which aims to give background magnetic fields, and on the overall characteristics of the system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.286-289
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• 2008

Damping materials are widely used to reduce vibration or noise generation of structures. To understand their damping capability and for use in numerical simulations, their viscoelastic properties should be measured in the frequency range of interest. In this study, experimental setup is proposed to measure materials properties of very compliant polymer materials. The polymer materials used in this study are difficult to form into rod shapes, and typical resonance methods are not applicable. In the proposed measurement setup, the damping materials were modeled as a simple viscoelastic support at one end of the beam. Their properties were measured through analysis of their effects on the wave propagation characteristics of the beam structure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.367-371
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• 2014

Based on ISO 7235, an experimental setup to measure the acoustic performance of splitter type dissipative silencers are fabricated. The length of each duct, sound source, microphone locations, modal filter, and anechoic termination are considered in the design of this setup. The modal filter is a particularly important factor because it affects the limit of measurement, which is also determined by the amount of flanking transmission of sound generated by the sound source to microphones. The effects of absorptive materials, media which covers the materials, and the number of splitters on the noise reduction of the sample silencers are experimentally investigated. The insertions loss of silencers with media and higher number of splitters increases, especially at higher frequencies.

• 산업기술연구
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• 제20권B호
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• pp.95-103
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• 2000

A model trains must have similitude with its original model not only in shape but also in motion. Motion characteristics of a model train under considerations are maximum velocity in straight and circular tracks and stopping distance. Equations of motions are derived to obtain maximum speed and stopping distance based on the Newton's Second Law and the energy principal. To accurately predict traction and resistance force between wheel and rail. wheel slip, or creepage, is taken into consideration. To verify the equations of motion, various experiments have been carried out including measurement of gear efficiency, location of mass center, rolling resistance force, traction force, slip, maximum velocity and stopping distance. This paper addresses how the experiments are setup and carried out in detail. Also the results of experiments are compared with the analytical prediction, which showed good agreements with each other.

• 동력기계공학회지
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• 제9권3호
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• pp.44-49
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• 2005

The aerodynamic performance of an indoor room air-conditioner using a cross-flow fan is strongly influenced by the various design factors of a rear-guider and a stabilizer. The purpose of this study is to investigate the effects of a rear-guider and a stabilizer on the aerodynamic performance in the maximum flowrate range of a cross-flow fan. The design factors considered in this study are a rear-guider clearance, a stabilizer cutoff clearance, and a stabilizer setup angle, respectively. Aerodynamic performances including maximum flowrate and power show the biggest magnitude distribution in the case of $45^{\circ}$, the stabilizer setup angle as well as nearly similar magnitude distribution regardless of the stabilizer cutoff clearances. Moreover, the more a rear-guider clearance increases, the more the magnitude of maximum flowrate and power increases.

• 산업경영시스템학회지
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• 제12권19호
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• pp.39-47
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• 1989

This paper considers a multi-stage flowshop scheduling Problem where the setup times of jots depend on immediately preceding jobs. Three heuristics algorithms, CAMPBELL, PEIDAN and CAMRING are proposed. The performance measure is a minimization of makespan. The parameters of simulation model are PS(ratio of the processing times to setup times), M(number of machines), and N(number of job). This simulation model for each algorithm is a 4$\times$3$\times$3 factorial design with 360 observations. The makespan of the proposed heuristic algorithms is compared with the optimal makespan obtained by the complete enumeration of schedules. This yardstick of comparison is defined as a relative error. The mean relative error of CAMPBELL, PEIDAN, and CAMRING algorithms are 4.353%, 7.908%, and 8.578% respectively. The SPSS, is used to analyse emphirical results. The experimental results show that the three factors are statistically significant at 5% level.