• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 춘계학술대회논문집
• /
• pp.155-160
• /
• 2001

This study is performed to evaluate and design the vibration characteristics of the onboard machinery with resilient mountings. To reduce the vibration level of onboard machinery with resilient mountings, it is important to evaluate and, if necessary, modify the vibration characteristics of the resilient mountings. In this study, we have developed a program to calculate natural frequencies of the machinery with resilient mountings, forced vibration levels due to internal excitation force of the machinery itself and external excitation forces. of the main engine and the propeller. and the force and motion transmissibility of the resilient mountings. The developed program is also able to be applied to optimal design of the resilient mountings for obtaining a target natural frequency and for achieving a minimum forced vibration level at the center of gravity of the machinery.

• 대한조선학회논문집
• /
• 제39권1호
• /
• pp.73-81
• /
• 2002

일반적으로, 선박에 탑재되는 장비의 진동문제는 장비자체의 기진력에 의한 진동문제뿐만 아니라 외부기진력인 주기관과 추진기의 기진력이 장비하부 데크를 통하여 장비에 과도 진동을 유발하는 경우가 많다. 따라서 본 연구에서는, 선박에 탑재되는 장비 마운팅 시스템의 진동 성능을 평가할 수 있도록 고유진동해석, 전달율계산, 강제진동해석 등을 수행할 수 있는 프로그램을 개발하였고, 선내 주요기진원과 장비의 공진시 공진회피를 위한 마운트 설계 변경 프로그램과, 그리고 장비 마운트 하부데크의 진동에 의한 장비의 무게중심에서 속도응답이 최소가 되도록, 마운트 강성을 결정하는 최적화 프로그램을 개발하였다.

• Archives of Pharmacal Research
• /
• 제21권6호
• /
• pp.779-781
• /
• 1998

The aim of this study is to provide evidence on the aphrodisiac property of Eurycoma longifolia Jack. An electric grid was used as an obstruction in the electrical copula tion cage in order to determine how much an aversive stimulus the sexually naive male rat for both the treated with E. longifolia Jack and control groups were willing to overcome to reach the estrous receptive female in the goal cage. The intensity of the grid current was maintained at 0.12mA and this was the intensity in which the male rats in the control group failed to crossover to reach the goal cage. Results showed that E. longifolia Jack continued to enhance and also maintain a high level of both the total number of successful crossovers, mountings, intromissions and ejaculations during the 9-12 th week observation period. In conclusion, these results further enhanced and strenghtened the aphrodisiac property of E.longifolia Jack.

• 소음진동
• /
• 제8권5호
• /
• pp.862-869
• /
• 1998

The interior noise generated by the windshield wiper system including a wiper motor, the motor mountings and linkages is considered as a structure-borne noise. The structureborne noise is closely related with the system vibration which was transmitted into interior cabin through the car body. In this study, the frequency characteristics of vibration in the wiper motor system were first identified through the frequency analysis. Then effects of the wiper motor mountings and linkages on the vehicle interior noise were studied through in-vehicle measurements. Finally a possibility of noise reduction at a certain frequency was revealed from the study.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 춘계학술대회논문집
• /
• pp.1128-1133
• /
• 2003

A gas driven heat pump (GHP) core design comprises internal combustion engine, compressors incorporated to a cooling/heating system, rubber mountings and belt transmissions. Main excitation farces are generated by an engine, compressors themselves and belt fluctuation. It leads to high vibration level of the mount that can cause damage of GHP elements. Therefore an appropriate design of the mounting system is crucial in terms of reliability and vibration reduction. In this paper oscillation of the engine mount is explored both experimentally and analytically. Experimental analysis of natural frequencies and operational frequency response of the GHP engine mounting system enables to create simplified model for numerical and analytical investigations. It is worked out criteria f3r vibration abatement of the isolated structure. Influence of bracket stiffness between engine and compressors, suspension locations and damper performance is investigated. Ways to reduce excitation forces and improve dynamic performance of the engine-compressor mounting system are considered from these analyses. Implementation of the proposed approach permits to choose appropriate rubber mountings and their location as well as joining elements design A phase matching technique can be employed to control forces from main exciters. It enables to changing vibration response of the structure by control of natural modes contribution. Proposed changes lead to significant vibration reduction and can be easily utilized in engineering practice.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2004년도 추계학술대회
• /
• pp.15-19
• /
• 2004

현재 국내에서는 NMEA 프로토콜 멀티플렉서를 개발한 사례 및 제품이 없어, 외국의 고비용 장비를 수입하여 사용하거나, 멀티 포트를 이용하여 NMEA 프로토콜을 전송하는 프로그램을 소프트웨어 적으로 구현하여 사용하고 있다. 이러한 방법은 고비용이 지출되거나, 각 응용프로그램마다 별도의 처리 부분을 작성해야하는 문제점이 있다. 또한, NMEA 프로토콜을 출력하는 각각의 장비들은 제조 회사 및 플랫폼이 다르므로 이중의 자원낭비 및 손실 등을 초래할 수 있다. 본 논문에서는 이를 보완하기 위하여 신뢰성 있는 처리방법과 고성능의 단일 하드웨어 모듈로서 독립적으로 동작할 수 있고 최적화된 큐의 설계를 이용하여 모듈의 메모리 효율을 높이며, 주요 입력 센서 장비인 자이로콤 파스, 에코 사운드, GPS 등의 장비들과 실시간 통신의 높은 신뢰성을 유지할 수 있는 NMEA 프로토콜 멀티플렉서를 구현에 대하여 제안하였다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 1996년도 춘계학술대회논문집; 부산수산대학교, 10 May 1996
• /
• pp.188-193
• /
• 1996

The purpose of resilient mounting for marine engine is to prevent noise and ship damages caused by engine vibration. Although many researches for the resilient mounting system have been carried out, these results have limit to apply on the marine engine systems. Because marine engine generally have low speed operating range and have to consider misfiring condition. In this paper, we studied the effect of engine's misfiring on the resilient mounting systems. And the influences of design parameters, such as dynamic characteristics and location angles of resilient rubber mountings, were also examined on the single and double resilient mounting systems.

• 한국자동차공학회논문집
• /
• 제5권4호
• /
• pp.84-92
• /
• 1997

Among the various sources of vehicle interior noise, this paper concerns the road induced noise ; the identification of its transfer path by using experimental method. Multiple input and single output model is taken as a noise generation model. Because it is impossible to measure the road imput forces directly, the acceleration signals are measured on four axle;three directions for each point. By considering the cross correlations of input signals, four uncorrelated source groups are taken. Multiple coherence function is employed to investigate the contribution of each group. In addtion, to identify the detailed path through the suspension systems, the contributions of all possible paths are ranked by using the coherence functions between interior noise and the relative accelerations of connections such as bushings and mountings. Measurements are performed with passenger vehicle traveling on concrete and asphalt roads at 60㎞/h.

• Journal of Biosystems Engineering
• /
• 제24권3호
• /
• pp.183-194
• /
• 1999

Using the dynamic model and simulation program TDA developed in the previous paper, effects of design parameters of an agricultural tractor-trailer system on its vertical seat vibrations were investigated. The tractor-trailer system was excited by traversing over a half-sine bump. The excitation frequencies were determined by traveling velocity of the tractor and a half-sine bump selected appropriately. TDA predicted the autospectra of the vertical seat accelerations with different values of design parameters and compared them to analyze their effects. The design parameters included positions of engine, cab, and seat mountings as well as their dynamic properties. The results of this study suggested guidelines with which an improved structure of tractor may be developed in the early stage of design for a better ride quality.

• 한국컴퓨터산업학회논문지
• /
• 제8권4호
• /
• pp.245-252
• /
• 2007

본 논문은 기존 전용선을 이용하는 대신에 PLC(Power Line Communication)를 이용하여 인터넷성능을 평가하고자 한다. 많은 통신망 장비와 작업의 어려운 문제를 단순히 전력선만으로 해결하고자한다. 이와 같이 전력선으로 인터넷을 이용하면 작업의 어려운 문제뿐만 아니라 초기 비용적인 측면에서도 크나큰 이득이 될 수 있다. 따라서 본 논문은 전력선을 이용하여 인터넷 이용이 어느 수준까지 활용할 수 있는가를 평가, 고찰해보고, 향후 전력선으로 인터넷을 활성화할 수 있는가에 대해 타당성을 고찰하였다.