• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2003년도 추계학술대회 논문집
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• pp.95-98
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• 2003

When a shock wave discharges from an open end of a duct, an impulse wave is generated outside the duct, causing serious noise and vibration problems. The magnitude of the impulse wave can be reduced by installing of a perforated duct. In the current study, the characteristics of the impulse wave discharged from the exit of a perforated duct are numerically investigated. A TVD (total variation diminishing) scheme is used to solve the unsteady, axisymmetric, compressible Euler equations. In computations, the porosity of a perforated pipe $(\sigma)$ and the Mach number of incident shock wave $(M_s)$ are varied in the range of $\sigma=0\~19\%\;and\;M_s=1.01\~1.50$, respectively. The results show that the directivity and magnitude of impulse wave strongly depend upon the Mach number of incident shock wave and the porosity of the perforated pipe. The present CFD results are in close agreement with experimental results.

• Journal of applied mathematics & informatics
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• 제18권1_2호
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• pp.145-158
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• 2005

We formulate a stochastic control problem on proportional reinsurance that includes impulse and regular control strategies. For the first time we combine impulse control with regular control, and derive the expected total discount pay-out (return function) from present to bankruptcy. By relying on both stochastic calculus and the classical theory of impulse and regular controls, we state a set of sufficient conditions for its solution in terms of optimal return function. Moreover, we also derive its explicit form and corresponding impulse and regular control strategies.

• KEPCO Journal on Electric Power and Energy
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• 제1권1호
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• pp.79-84
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• 2015

Transformer is widely used element on power system and industrial area. Especially the transformers installed at power system are exposed to an environment of arbitrary changed. Thus the prediction of degradation and the analysis of response to impulse are important. To conduct those works, the electrical characteristics of system should be analyzed, effectively. But the analysis of electrical characteristic in electric machine level such as pole and pad-mounted transformer is almost no, thus commercial VNA (Vector Network Analyzer) is used to getting the response in wide frequency range. However, the output power of VNA is usually under 10mW, so verification for effectiveness of measuring electrically large component should be conducted, firstly. Next, after getting total S-parameter of transformer, predicting impulse response can be performed in time-domain with circuit simulator. In this paper, it is introduced that verification effectiveness of VNA using transfer function from SFRA (Sweep Frequency Response Analyzer), firstly. Next, total S-parameter, six by six matix form, was built using measured 2 port S-parameter from vector network analyzer. To get the response to impulse which is defined by IEC 60060-1, time-domain simulation is conducted to ADS (Advenced Design System) circuit simulator.

• 한국의류산업학회지
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• 제15권4호
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• pp.533-542
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• 2013

Fashion products are frequently purchased on impulse and are also one of the most popular product categories sold online. Online environment attributes can facilitate flow experiences that are described as an optimal psychological state reached during an engagement in activities (e.g., games and e-shopping). This study estimated the path model to examine the causal relationships among shopping mall attributes, flow, e-impulse buying, and consumer satisfaction for fashion products. A total of 598 usable questionnaires were obtained from college students who had purchased fashion products through the Internet. Data were analyzed by exploratory factor analysis, confirmatory factor analysis, and path analysis using SPSS 18.0 and AMOS 18.0. The results showed that e-shopping mall attributes (visual attributes and product attributes) significantly influenced e-impulse buying (fashion-oriented impulse buying and promotion-oriented impulse buying) which was mediated by the consumer flow experience and then influenced by consumer satisfaction. In the path model, the flow was stimulated by shopping mall attributes, the e-impulse buying was influenced by flow, and the consumer satisfaction was influenced by e-impulse buying. Flow was the most highly related to the fashion-oriented impulse buying, and followed by the relationship of the flow and promotion-oriented impulse buying in the context of e-shopping for fashion products. A managerial implication was discussed for fashion product e-retailers to develop strategies on visual attributes and product attributes that could stimulate and increase the consumer flow to trigger impulse buying as well as consumer satisfaction.

• 한국의류학회지
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• 제34권12호
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• pp.1947-1956
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• 2010

This study is to understand fashion product aesthetics by exploring the antecedents of aesthetic experiences and the influence of aesthetic experiences on impulse buying behavior. A total of 520 usable questionnaires were obtained through an internet survey. A structural equation model using a correlation matrix with maximum likelihood was estimated by using AMOS 18.0 to examine the relationships among aesthetic value, aesthetic acumen, affective experience, cognitive experience, and impulse buying behavior. The results showed that aesthetic value and acumen had a significant effect on the cognition of aesthetic experiences and that aesthetic experiences had a significant effect on impulse buying behavior. These results highlight the powerful motivational force behind fashion product aesthetics. The key implications for research and management are discussed further.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.544-549
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• 2003

When a shock wave arrives at an open end of tube, an impulse wave is discharged from the tube exit and causes serious noise and vibration problems. In the current study, the effect of the cross-sectional area of tube on the impulse wave is numerically investigated using a CFD method. The Harten-Yee's total variation diminishing(TVD) scheme is used to solve the axisymmetric, two-dimensional, unsteady, compressible Euler equations. With three different cross-sectional areas of tube, the Mach number of the incident shock wave $M_{s}$ is varied between 1.01 and 1.5. The results obtained show that the directivity and magnitude of impulse wave strongly depend upon the Mach number of incident shock wave and are influenced by the tube area. It is also known that the tube cross-sectional area significantly affects the magnitude of impulse wave at or near the tube axis.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.550-555
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• 2003

When a shock wave arrives at an open end of tube, an impulse wave is discharged from the tube exit and complicated flow is formed near tube exit. The flow field is influenced by the cross-sectional geometry of tube exit, such as circular, square, rectangular, trapezoid and etc. In the current study, three-dimensional propagation characteristics of impulse wave discharged from the tube exit with non-circular cross section are numerically investigated using a CFD method. Total variation diminishing (TVD) scheme is used to solve the three-dimensional, unsteady, compressible Euler equations. Computations are performed for the Mach numbers of the incident shock wave $M_{s}$ below 1.5. The results obtained show that the peak pressure of the impulse wave and propagation directivity depends on the cross-sectional geometry of tube exit and the Mach number of incident shock wave.

• 대한가정학회지
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• 제45권6호
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• pp.113-122
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• 2007

본 연구의 목적은 의류판매 온라인 쇼핑몰 상에서의 충동구매행동과 의류판매 사이트의 프로모션, 제품/정책 정보간의 관계를 알아보기 위한 것이다. 인터넷 설문지를 통한 데이터 수집을 통해 236부가 본 연구에 사용되었다. 결과 분석 이전에 웹사이트특성을 분류하기 위해 요인분석을 실한 결과 웹사이트 특성이 프로모션과 제품/정책 정보로 구분되었다. 연구결과 충동구매를 한 집단의 의류판매 사이트의 프로모션과 제품/정책 정보에 대한 평가가 그렇지 않은 집단보다 높게 나타났고 충동구매집단의 충동구매성향과 의류판매 사이트의 프로모션, 제품/정책 정보에 대한 평가는 정적인 상관관계를 가지는 것으로 나타났다.

• 대한물리치료과학회지
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• 제11권4호
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• pp.29-37
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• 2004

Measurements of plantar pressure provide an indication of foot and ankle function during gait and other functional activities because the foot and ankle provide necessary support and flexibility for weight bearing and weight shifting while people are performing these activities. Plantar pressure is being increasingly used in both research and clinical practice to measure the effects of various footwear and physical therapy intervention. The influence of walking speed and ground inclination on plantar pressure parameters However has not been evaluated in detail. So, in this study to determine the effect of changes in walking speed and ground inclination on plantar pressure treadmills with different walking speeds and inclination were used. Plantar pressure parameters were measured with the Parotec system using the walking and running in 20 healthy participants(10 male, 10 female) aged $20{\sim}28$(mean 22.22, S.D.2.26 years) when slow walking and running. The result of this study with increased die walking speed, the peak pressure of 1st, 5th metatarsal head and total contact time and impulse total at the forefoot was affected by walking speed; however, die peak pressure, contact time and impulse total at the forefoot was not affected by ground inclination.

• 한국소음진동공학회논문집
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• 제12권5호
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• pp.346-354
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• 2002

The present study is to investigate the propagation characteristics of the impulse waves discharged from the exit of the convergent and divergent pipes. An experiment is carried out using a shock tube with an open end and is compared to the computation of the axisymmetric, compressible, unsteady Euler equations, which are solved by the second-order total variation diminishing (TVD) scheme. For the computational work, several initial compression waves are assumed inside the pipe so that those are the same to the experimental ones of the shock tube. The results show that the peak pressures of the impulse waves discharged from the exit of convergent and divergent pipes decrease with an increase in the wavelength of the initial compression wave. All of the impulse waves have a strong directivity toward the pipe axis, regardless of the exit type of the pipe employed. The impulse waves discharged from the divergent pipe are stronger than those from the straight pipe, while the impulse waves of the convergent pipe are weaker than those from the straight pipe. It is found that the convergent pipe can play a role of a passive control to reduce the peak pressure of the impulse wave. The present computations represent the experimented impulse waves with a good accuracy.