• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.101.1-101
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• 2002

Vehicle driving simulator is a virtual reality device which makes a human being feel as if the one drives a vehicle actually. Unlike actual vehicle, the simulator has limited kinematic workspace and bounded dynamic characteristics. So it is difficult to simulate dynamic motions of a multi-body vehicle model fully. In order to overcome these problems, washout algorithm which restricts workspace of the simulator within the kinematic limits is needed, and analysis of dynamic characteristics is required also. However, it is difficult to select the proper cutoff frequency of filters in washout algorithm. This paper introduces the signal compression method as an effective method to analyze the sim...

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.741-744
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• 2003

본 논문은 모자이크 배경을 생성하고 변화되는 정보만을 전송함으로서 동적기반 압축시스템을 제안한다. 동적 모자이크 배경은 카메라 움직임 정보를 이용하여 단일영상으로 점진적으로 통합된다. 카메라 움직임 예측을 위해 각각의 영상들과 이전영상과의 원근투영 매개변수를 순차적으로 계산하였다. 카메라 움직임은 배경영역과 전경영역에서 식별함으로서 배경상에서 강건하게 계측된다. 수정된 블록기반 움직임계측은 배경영역을 분리하는데 이용되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.168-170
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• 1997

This paper presents the dynamic analysis of a reciprocating actuation system based on moving magnet actuator for gas compression. For the analysis of the linear actuator, an axisymmetric finite element method (FEM) considering the saturation effect of the magnetic material is used, and electrical circuit equation, mechanical dynamic equation and pressure dynamics are coupled. In the FE analysis, we adopt a moving line technique. The pressure dynamics of the gas in the compressor is modeled by using the law of thermodynamics. The analysis results are compared fairly well with experimental ones.

• Structural Engineering and Mechanics
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• 제3권3호
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• pp.229-244
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• 1995

The parametric instability behaviour of a plate subjected to localized in-plane compressive or tensile periodic edge loading is studied, considering the effects of damping into the system. Different edge loading cases have been considered. Damping has been introduced in the form of proportional damping. Dynamic instability behaviour under compressive or tensile periodic edge loading shows that the instability regions are influenced by the load band width and its location on the edge. The effects of damping on the instability regions show that there is a critical value of dynamic load factor beyond which the plate becomes dynamically unstable. The critical dynamic load factor increases as damping increases. Damping generally reduces the widths of the instability regions.

• 대한정형도수물리치료학회지
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• 제25권1호
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• pp.63-70
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• 2019

Background: The purpose of this study was to determine the effects of a pelvic compression belt on gait abilities and balance in subacute stroke patients. Methods: Twenty two patients with subacute were recruited and randomly assigned into two group: Two group offered conventional physical therapy and occupational therapy for five day. The group was composed of twelve patients. Participants in the experimental group were given the pelvic compression belt and conventional physical therapy, conventional occupational therapy, although conventional physical therapy and occupational therapy provided in the subjects in the control group. To assess the gait ability, the GAITRITE system was used and the Balance system SD was used to test balance. All measurements were performed before and after intervention. Results: The experimental group shows a significant improvement the cadence, velocity, step length and stride length in gait (p<.05) and show significant increase in the dynamic standing balance (p<.05). However, control group shows a significant improvement the cadence, velocity, step length and stride length in gait (p<.05), but shows no significant differences in dynamic standing balance. Furthermore, there were significant differences gait velocity, dynamic standing balance between two groups (p<.05). Conclusions: The results demonstrated that the elastic pelvic belt application is effective to improve gait velocity, dynamic balance in the subacute stroke patients. Thus, the elastic pelvic belt is seemed to be one of the potential methods to facilitate the active rehabilitation program for hemiplegia patients.

• 한국엔터테인먼트산업학회논문지
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• 제13권2호
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• pp.93-100
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• 2019

현대 대중음악의 보컬 녹음에서 소리의 다이내믹을 압축해주는 컴프레서는 필수적인 장비이다. 컴프레서는 음악청취를 위한 믹스에서 뿐 아니라 가수가 녹음을 하는 중에 반주와 함께 자신의 목소리를 듣기 위한 모니터에 적용되기도 한다. 이 연구는 보컬 녹음에 있어 모니터 환경에 적용된 컴프레서가 가수의 가창에 미치는 영향에 대한 실험 연구다. 10명의 참여 가수를 섭외하여 블라인드 테스트로 모니터를 통해 들리는 보컬에 1:1, 2:1, 4:1의 압축 비율의 컴프레서를 걸어 가창에 어떻게 영향을 받는지를 실험하였다. 실험 결과 모니터에 적용된 압축 비율이 높을 수록 다이내믹이 큰 부분에서 더 크게 노래하고, 음색이 더 밝았지만 음정은 미세하게 부정확해지는 결과가 나타났다. 블라인드를 유지한 상황에서의 사후 인터뷰 결과 가수들은 모니터에 컴프레서를 통해 압축된 소리를 듣는 것을 대체로 선호하는 것도 발견되었다. 실험에서 사용한 음악이 다이내믹의 범위가 넓은 발라드곡이었기 때문에 모든 음악 녹음에 일반화할 수는 없지만 녹음 현장의 모니터링에 대한 중요한 시사점을 제공할 수 있을 것으로 생각한다. 또한 모니터 환경에 따른 가수의 가창에 미치는 영향에 대해 실증 연구를 통해 연구된 본 논문을 바탕으로 녹음 기술에 대한 인지과학적 접근이 추가로 이루어지기를 희망한다.

• Structural Engineering and Mechanics
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• 제66권3호
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• pp.295-303
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• 2018

The semi-analytical method to study the nonlinear dynamic behavior of simply supported spiral stiffened functionally graded (FG) cylindrical shells subjected to an axial compression is presented. The FG shell is surrounded by damping and linear/nonlinear elastic foundation. The proposed linear model is based on the two-parameter elastic foundation (Winkler and Pasternak). A three-parameter elastic foundation with hardening/softening cubic nonlinearity is used for nonlinear model. The material properties of the shell and stiffeners are assumed to be FG. Based on the classical plate theory of shells and von $K{\acute{a}}rm{\acute{a}}n$ nonlinear equations, smeared stiffeners technique and Galerkin method, this paper solves the nonlinear vibration problem. The fourth order Runge-Kutta method is used to find the nonlinear dynamic responses. Results are given to consider effects of spiral stiffeners with various angles, elastic foundation and damping coefficients on the nonlinear dynamic response of spiral stiffened simply supported FG cylindrical shells.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.167-170
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• 1997

For the optimal net shape forging of semi-solid materials (SSM), it is important to predict the deformation for variation of strain rate. It should be necessruy to conduct a formation of stress-strain curve in semi-solid alloys for analysis of the thixoforming process. Particularly, important problem to application of computer aided engineering in SSM processing is to prevent a segregation of liquid component during compression process. The liquid segregation is studied as multistage change of the strain rate and test piece size to prevent the liquid segregation during the compression process. The compression test for semi-solid aluminium alloy with a controlled solid fraction is performed by dynamic material test system with a furnace. Moreover morphology of structure and fraction of pore are investigated through compression test.

• Structural Engineering and Mechanics
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• 제52권4호
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• pp.687-699
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• 2014

Based on the energy method considering the second order effects, the natural frequencies of externally prestressed simply supported beam and the compression softening effect of external prestress force were analyzed. It is concluded that the compression softening effect depends on the loss of external tendon eccentricity. As the number of deviators increases from zero to a large number, the compression softening effect of external prestress force decreases from the effect of axial compression to almost zero, which is consistent with the conclusion mathematically rigorously proven. The frequencies calculated by the energy method conform well to the frequencies by FEM which can simulate the frictionless slide between the external tendon and deviator, the accuracy of the energy method is validated. The calculation results show that the compression softening effect of external prestress force is negligible for the beam with 2 or more deviators due to slight loss of external tendon eccentricity. As the eccentricity and area of tendon increase, the first natural frequency of the simply supported beams noticeably increases, however the effect of the external tendon on other frequencies is negligible.

• 대한임베디드공학회논문지
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• 제11권2호
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• pp.79-86
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• 2016

In wireless sensor networks, increasing the sensing rate of each node to improve the data accuracy usually incurs a decrease of network lifetime. In this study, an energy-adaptive data compression scheme is proposed to efficiently control the sensing rate in an energy-harvesting wireless sensor network (WSN). In the proposed scheme, by utilizing the surplus energy effectively for the data compression, each node can increase the sensing rate without any rise of blackout time. Simulation result verifies that the proposed scheme gathers more amount of sensory data per unit time with lower number of blackout nodes than the other compression schemes for WSN.