• 한국소음진동공학회논문집
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• 제22권2호
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• pp.179-186
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• 2012

The potential hazards resulting from a low-velocity impact(bird-strike, tool drop, runway debris, etc.) on aircraft structures, such as engine nacelle or leading edges has been a long-term concern to the aircraft industry. Certification authorities require that exposed aircraft components must be tested to prove their capability to withstand low-velocity impact without suffering critical damage. In most of the past research studies unloaded specimens have been used for impact tests, however, in reality it is much more likely that a composite structure is exposed to a certain stress state when it is being impacted, which can have a significant effect on the impact performance. And the radiated impact sound induced by impact is analyzed for the damage detection evaluation. In this study, an investigation was undertaken to evaluate the effect in-plane loading on the impact force and sound of composite laminates numerically.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.890-895
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• 2001

Pressure resonance frequency that is caused in the combustion chamber can be interpreted to acoustic analysis. Until now the pressure resonance has been assumed and calculated to a disc type combustion chamber that neglected the combustion chamber height because the knock occurs near the TDC(top dead center). In this research FEM(fine element method) has been used to calculate the pressure resonance frequency inside the experimental engine combustion. The reduce error of the resonance frequency obtained by FEM has decreased about 50% compared to the calculation of Draper's equation. Due to the asymmetry in the shape of the combustion chamber that was neglected in Draper's equation we could find out that a new resonance frequency could be generated. To make the experimental results equal we could know that the speed of sound that satisfies Draper's equation was selected 13% higher than all the pent-roof type combustion considered.

• 한국소음진동공학회논문집
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• 제26권7호
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• pp.774-780
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• 2016

In this paper noise source and transfer path of tactical vehicle are analyzed with partial coherence function and spectrum analysis. Engine, transmission, structure panel and aerodynamic are main source of cabin noise. To reduce cabin noise, identifying transfer path of sources and analyzing their contribution is important. With modeling of transfer path and partial coherence function, transfer path and principal noise source can be identified. Engine/transmission and structural resonance are principal source of low frequency noise and by adding stiffener and sound absorbing material, resonance of vibration and inflow air problem can be solved.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1487-1492
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• 2000

To identify forklift's booming noise in cabin under idling engine revolution, we discussed and applied conditioned input analysis. Acceleration signals at engine mounts and front window and rear window were considered as candidate input signals and output signal was sound pressure signal at driver's ear position in cabin. To reduce the numbers of the input signals, one idea were applied; Each one input signal from each input groups was selected, respectively because input signals in the same group were highly correlated. And Hilbert transform was used to determine the ordering of three selected inputs. Partial coherence functions, multiple coherence function and conditioned spectral density functions were investigate to the effects of booming noise by partial inputs.

• 한국생산제조학회지
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• 제6권3호
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• pp.96-102
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• 1997

Eigenvalue analysis of vibration mode and an analysis by frequency response among the methods of predicting gear noise are related with transmitting sound of vibration. In this study we intended to reduce the vibration noise of differential gear by reducing torque fluctuation of drive pinion shaft which causes vibration noise of differential gear in rear wheel drive vehicles. For this we developed multi-degree of freedom analysis model in which mass moment of inertia and torsional spring combined and we examined the influence of torsional vibration of driveline elements by performing forced vibration analysis of engine excitation torque. We studied the methods for reducing torsional vibration of driveline according to the design factor of propeller shaft and examined the effects reducing vibration in differential gear by applying flexible coupling.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.341-346
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• 2014

Intake E-CVVT noise, generally caused by collision sound of roller and cage clearance at idle and driving condition, is considerable source of annoyance in passenger cars using the gasoline engine. Main source of this noise is the cam torque variation of an intake E-CVVT system, and can be controlled by clearance decrease such as backlash reduction, but which may increase the manufacturing cost. Thus in this paper, most effective solution for low noise intake E-CVVT was achieved through not only reduction of backlash and cam angular acceleration but also improvement of vehicle transfer system, which is optimal configuration through acoustic sensitivity optimization of engine mount support bracket.

• 한국자동차공학회논문집
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• 제6권4호
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• pp.151-159
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• 1998

The heavy equipment such as tracter has been studied to improve rather the performance of engine than comfort. The mufflers of tracters have various specifications according to their uses. The exact analysis of various mufflers is needed to reduce the level of exhaust moise, a major noise source of engine, to improve the ride quality of tracter. In this study, a software based on Green's function is developed to predict the performance of sound transmission loss for a muffler according to the locations of inlet/outlet pipes. The locations of inlet and outlet pipes can be fixed at different position individually. The conventional muffler has the locations of inlet/outlet pipes on the direction of longitudinal axes. On other hand, the inlet and outlet pipes may be located at the circumferential surface of a test muffler such as one of tracter. The software is verified by analysis and experiment on current muffler of tracter and the improvement technique is proposed to reduce the level of exhaust noise.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.769-772
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• 2013

When developing engine mount, interm mount bracket 1st resonance is critical to make sound quality better or worse. So, at the initial stage of development, we need to consider some design parameter to setup the target of interm bracket 1st resonance. Especially, 3cylinder interm bracket guideline is not well known. So, this paper deals with some important sensitivity which should be considered during the development of vehicle. From source to interior side, we should know the component sensitivity like body sensitivity p/F or bracket gain etc. Through this paper, we could get the knowledge of design guideline and key consideration points.

• International Journal of Contents
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• 제18권1호
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• pp.98-104
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• 2022

With Unity creating footage is possible by using 3D motion, 2D motion, particular, and sound. Even post-production video editing is possible by combining the footage. In particular, Cinemachine, a suite of camera tools for Unity, that greatly affects screen layout and the flow of video images, can implement most of the functions of a physical camera. Visual aesthetics can be achieved through it. However, as it is a part of a game engine. Thus, the understanding of the game engine should come first. Also doubts may arise as to how similar it is to a physical camera. Accordingly, the purpose of this study is to examine the advantages and cautions of virtual cameras in Cinemachine, and explore the potential for development by implementing storytelling directly.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 1999년도 학술대회지 vol.2
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• pp.575-586
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• 1999

The advent of the Internet and the enormous increase in volume of electronically stored information (SGML, Image, Sound, etc.) has led to substantial work on IR(Information Retrieval). To service on the WWW, construction and retrieval technology of SGML, which is the fundamental standard data format for CALS/EC, is needed specially. Due to such a change, it becomes essential to change the existing paradigm of conventional information retrieval systems and to adopt new Internet service system with search engine, SGML browser and advanced Internet technology on WWW. KIPRIS(Korea Industrial Property Rights Information Service), which is the specialized and integrated Internet service systems in the field of industrial property rights information service, is trying to be a guide for our country to establish its technological competitiveness with providing the online service of high quality. The objective of the paper identifies features and technologies of KIPRIS IR(Information Retrieval) system based on WWW as follows. First, it describes the development background and process of KIPRIS. Second, it presents a fundamental technology that consists of IR(Information Retrieval) concept, BRS(Bibliographical Retrieval System) search engine, SGML implementation technologies and the Internet/WWW technologies. Third, it provides information about system configuration, architecture, and the features and characteristics of KIPRIS. Finally, the implemented KIPRIS system is introduced.