• 한국자동차공학회논문집
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• 제3권3호
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• pp.119-128
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• 1995

A driver-vehicle model means the integrated dynamic model that is able to estimate the steering wheel angle from the driver's desired path based on the dynamic characteristics of the driver and vehicle. In this paper, the dynamic characteristics of several four-wheel steering systems with the simultaneously steerable front and rear wheels are investigated and compared by means of the driver-vehicle model. Especially, the presented analysis results are obtained by using the ISO test codes such as lane change, double lane change and slalom, and the effects of the driver's steering response time and vehicle speed are examined on the responsiveness and stability of vehicle.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.832-936
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• 1996

In this paper, we study a dynamic characteristics of HDD. HDD is constructed by spindle motor/disk unit, cover, base, E-block arm/suspension unit, and rotary actuator/voice coil motor. First, we make a FE model of spindle motor/disk unit and analyzed natural frequency/mode analytically and experimentally. Especially, the change of natural frequecy of spindle motor unit according to change of B.C is considered. Second, FE model of cover, base is made. Third, we assemble the above three FE mode, we get HEE assembly and dynamic analysis of HDD assembly is accomplished.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.244-249
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• 1997

Internal and external heat sources will cause to deform to machine elements in the contact joint of structure,which results in the change of contact pressure distribution different from initial assembly. Heat induced variations of contact pressure will change the static and dynamic properties such as contact stiffness,damping as well as contact heat conduction in the structure. In order to design and control the intelligent machine tool operating in variant conditions more sophisticatedly, the good prediction for the changes of prescribed propeties are strongly required especially in the contact elements adjacent to the rotational or linear bearing This paper presents some computational and experimental results in regard to static and dynamic characteristics of the press-fitted bush and shaft assembly which is a model of the bearing innerrace and shaft assembly. In the condition of heat generation on the outer surface of the bush,the effects of changes in the negative clearance and the heat flux on pressure distribution and dynamic properties are investigated. Results of this study show that the edge effect of the bush and the initial clearance have effects on the transient dynamic characteristics significantiy.

• 전기학회논문지P
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• 제57권1호
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• pp.14-21
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• 2008

In this paper, we propose an adaptive contrast enhancement method using dynamic range segmentation. Histogram Equalization (HE) method is widely used for contrast enhancement. However, histogram equalization method is not suitable for commercial display because it may cause undesirable artifacts due to the significant change in brightness. The proposed algorithm segments the dynamic range of the histogram and redistributes the pixel intensities by the segment area ratio. The proposed method may cause over compressed effect when intensity distribution of an original image is concentrated in specific narrow region. In order to overcome this problem, we introduce an adaptive scale factor. The experimental results show that the proposed algorithm suppresses the significant change in brightness and provides wide histogram distribution compared with histogram equalization.

• 한국수자원학회논문집
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• 제31권4호
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• pp.407-413
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• 1998

본 연구는 기후 변화가 수자원 시스템에 미치는 영향에 대한 최근의 연구 동향을 살펴보고, 그 중의 한 기법을 미국의 Skagit 시스템에 실례로 적용해 보았다. 적용된 기법에서는, 기후변화로 인하여 Skagit 시스템의 월별 유입량의 평균과 분산이 $\pm$5% 증가한다고 가정하였다. 평균과 분산이 변화한 각각의 경우에 대하여 월별 운영률을 추계학적 동적 계획법으로 구하고 기후 변화가 없다고 가정한 경우의 운영률과 비교하였다. 그 결과 Skagit 시스템의 월별 운영률은 유입량 분산의 변화보다는 평균의 변화에 더욱 민감함을 보였다. 또, 결정된 운영률들은 모의 발생된 유입량 시나리오들을 이용하여 그 효율성을 비교하였는데, 운영률의 평가 지표로는 평균 연간 수익을 사용하였다. 산출된 운영률 중 가장 최선의 운영률을 선택하기 위하여, 본 연구에서는 Bayesian 결정 기법을 간단한 예로 설명하였다.

• Communications for Statistical Applications and Methods
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• 제3권1호
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• pp.207-217
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• 1996

The problem of detecting change with independent data is considered. The asymptotic distribution of the sample change process with the sample Fourier coefficients is shown as a Brownian Bridge process. We suggest to use dynamic statistics such as a sample Brownian Bridge and graphs as statistical animation. Graphs including change PP plots are given by way of illustration with the simulated data.

• 한국수소및신에너지학회논문집
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• 제35권2호
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• pp.121-128
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• 2024

In this study, a dynamic simulation model of a heavy-duty truck, equipped with a fuel cell power-train, has been developed and the dynamic behavior of the fuel cell stack has bee investigated using. Output change simulations were performed according to several drive cycle load change of a fuel cell truck. Mathworks' Simulink and Simscape program were used to develop the model. The model is comprised of fuel cell power train, power converter system and truck vehicle part. The vehicle runs at targeted speed of the truck, which is set as the load of the system. The dynamic behavior of the fuel cell stack according to the weight difference were analyzed, and based on this, the dynamic characteristics of the fuel cell output power and battery state with simple load was analyzed.

• Journal of Obesity & Metabolic Syndrome
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• 제27권4호
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• pp.203-212
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• 2018

Dynamic energy balance can give clinicians important answers for why obesity is so resistant to control. When food intake is reduced for weight control, all components of energy expenditure change, including metabolic rate at rest (resting energy expenditure [REE]), metabolic rate of exercise, and adaptive thermogenesis. This means that a change in energy intake influences energy expenditure in a dynamic way. Mechanisms associated with reduction of total energy expenditure following weight loss are likely to be related to decreased body mass and enhanced metabolic efficiency. Reducing calorie intake results in a decrease in body weight, initially with a marked reduction in fat free mass and a decrease in REE, and this change is maintained for several years in a reduced state. Metabolic adaptation, which is not explained by changes in body composition, lasts for more than several years. These are powerful physiological adaptations that induce weight regain. To avoid a typically observed weight-loss and regain trajectory, realistic weight loss goals should be established and maintained for more than 1 year. Using a mathematical model can help clinicians formulate advice about diet control. It is important to emphasize steady efforts for several years to maintain reduced weight over efforts to lose weight. Because obesity is difficult to reverse, clinicians must prioritize obesity prevention. Obesity prevention strategies should have high feasibility, broad population reach, and relatively low cost, especially for young children who have the smallest energy gaps to change.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.682-686
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• 2002

This study predicts the sensitivity coefficient by the change of dynamic Characteristics of the Structure. The method is applied to examples of a cantilever and 3 degree of freedom lumped mass model by modifying the mass and stiffness. The predicted the sensitivity coefficient are in good agreement with these from the structural reanalysis using the modified mass and stiffness.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.125-128
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• 2003

In this paper, we propose a dynamic key lifetime change protocol for performance enhancement of virtual private networks using IPSec. The proposed protocol changes the key lifetime according to the number of secure tunnels. The proposed protocol is implemented with Linux 2.4.18 and FreeS/WAN 1.99. The system employing our proposed protocol performs better than the original version in terms of network performance and security.