• 대한기계학회논문집B
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• 제26권9호
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• pp.1319-1324
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• 2002

A theoretical model on shock-vortex interaction is investigated using a numerical technique to solve Navier-Stokes equations. The shock-vortex interaction generated by this model based on the classical Rankin vortex is precisely investigated for a benchmark problem: Dosanjh and Weeks experiment. In terms of shock dynamics, the interaction is categorized to three stages: shock distortion, shock split, and shock-shock interaction. The quadrupolar structure of the sound source produced by the interaction is far supported with the present model, and the difference between experiment and theoretical model is also discussed in this paper.

• 한국군사과학기술학회지
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• 제24권1호
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• pp.70-78
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• 2021

Naval surface ships and submarines could be exposed to non-contact underwater explosion(UNDEX) environment. Equipment installed on the ships and submarines could be damaged by shock load generated by UNDEX environment. Therefore, shock survivability of equipment generally evaluated by shock tests. Ground based shock test machine such as Light weight shock test machine(LVSM) is developed to simulate shock load caused by UNDEX environment. In this study, linear dynamic model of LVSM is proposed and evaluated to improve shock test design procedure. Parameters of the model are decided by optimizing time domain response compared to zero payload experiment. Proposed model is verified by comparing simulation results and test results of maximum payload experiment. Finally, shock test design using the model is described for various test equipment weight.

• 약학회지
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• 제48권1호
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• pp.82-87
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• 2004

Mungbean trypsin inhibitor (MBTI) was isolated and purified from Mung bean which has been used as a galenic and traditional food. MBTI and poly(ethylene glycol) were conjugated by using water soluble carbodiimide. We evaluated the therapeutic value of the MBTI and MBTI-PEG conjugate using animal models, sublethal septic shock model in guinea pig caused by pseudomonal elastase, shock model in rat caused by lipopolysaccharide, and the vascular permeability test by using pseudomonal elastase. In two shock model in guinea p Is and in rat, hypotesion shock was inhibited by pretreatment of MBTI. And also the vascular permeability caused by pseudomonal elastase reduced by pretreatment of MBTI. Also, therapeutic value of the MBTI-PEG conjugate was evaluated by using the sublethal septic shock model caused by pseudomonal elastase. The MBTI-PEG conjugate was more effective than native MBTI against pseudomonal elastase induced septic shock in guinea pig model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권4호
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• pp.1080-1099
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• 2023

Digital healthcare combined with telemedicine services in the form of convergence with digital technology and AI is developing rapidly. Digital healthcare research is being conducted on many conditions including shock. However, the causes of shock are diverse, and the treatment is very complicated, requiring a high level of medical knowledge. In this paper, we propose a shock detection method based on the correlation between shock and data extracted from hemodynamic monitoring equipment. From the various parameters expressed by this equipment, four parameters closely related to patient shock were used as the input data for a machine learning model in order to detect the shock. Using the four parameters as input data, that is, feature values, a random forest-based ensemble machine learning model was constructed. The value of the mean arterial pressure was used as the correct answer value, the so called label value, to detect the patient's shock state. The performance was then compared with the decision tree and logistic regression model using a confusion matrix. The average accuracy of the random forest model was 92.80%, which shows superior performance compared to other models. We look forward to our work playing a role in helping medical staff by making recommendations for the diagnosis and treatment of complex and difficult cases of shock.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 추계학술대회논문집
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• pp.185-187
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• 2009

A density based method with homogeneous cavitation model to investigate cavitation-bubble collapsing behavior is proposed and applied to bubble-shock interaction problems. By applying this method, cylindrical bubbles located in the liquid and incident liquid shock wave are computed. Bubble collapsing behavior, shock-bubble interaction and shock transmission/reflection pattern are investigated.

• International Journal of Reliability and Applications
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• 제4권2호
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• pp.71-77
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• 2003

We propose, in this paper, the discrete version of NBU$_{Mg}$and show that the NBU$_{Mg}$ class is preserved under both the non-homo geneous poisson shock model and the general shock model.

• 한국ITS학회 논문지
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• 제11권4호
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• pp.51-62
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• 2012

Lighthill과 Whitham의 충격파모형에 따르면 동일한 속도를 유지하는 교통류 흐름상태에서도 충격파가 존재하며, 이는 라디오 전파처럼 보이지도 않고 관측할 수도 없다고 하였다. 최근의 한 논문은 이 문제에 대해 새로운 접근방법을 통해 위와 같은 모순이 어떻게 발생하였는지를 보여주었고, 이를 개선하기 위해 점근적 충격파모형 (asymptotical shock wave model) 을 제시하였다. 점근적 충격파모형은 동일한 속도로 이동하는 균일한 교통류에서 라디오 전파와 같은 관측 불가능한 충격파가 존재하지 않는 것을 증명하였다. 그러나 상기 논문은 모형의 유도와 증명에 치중하였고 모형으로서의 해석이나 구체적인 수치를 적용한 모형의 검증은 아직 실행된 적이 없다. 본 논문은 점근적 충격파모형의 내포된 의미를 해석하고, 구체적인 수치를 바탕으로 한 시나리오를 통해 모형의 성능을 시험하였다. 그 결과 점근적 충격파모형은 기존 모형에 비해 수식상의 큰 차이는 없었지만, 유일한 차이인 등식의 세 번째 항목이 모형 결과에 결정적인 차이를 나타냄을 확인하였다. 새 모형에 도입된 파라메터는 적용된 수치의 대소에 따라 그 결과가 다르게 나타났다. 이는 기존의 충격파모형에는 없는 특징으로서, 적절한 수치를 선정한다면 다양한 교통흐름에 신축적으로 모형을 적용할 수 있을 것으로 판단된다. 또한 구체적인 수치를 적용한 점근적모형의 시나리오별 시험 결과 동일한 조건에서 새로운 모형은 기존 모형에 비해 충격파가 교통류의 하류 측으로 더 진행됨을 확인하였다. 양 모형간의 이러한 차이는 통계적 유의성 검토에서도 확인되었으며, 향후 현장 자료를 적용한 추가적 비교연구가 필요한 것으로 사료된다.

• 한국소음진동공학회논문집
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• 제16권11호
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• pp.1108-1114
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• 2006

Underwater acoustic transducers can be exposed to a underwater explosive shock caused by various types of underwater weapon. So, a robust anti-shock design is required for transducers to endure the underwater explosive shock. To check the anti-shock characteristics of a transducer, underwater explosive shock test is needed. The conditions of underwater explosive shock test are set up referring to various oversea explosive shock test specifications, and the explosive shock pressure values are calculated according to those conditions. Transient analyses art: carried out for two kinds of underwater acoustic transducer model to verify the anti-shock characteristics. The applied model has robust anti-shock characteristics enough to endure the explosive shock up to 2300 psi. In the future, the transducer design should be certified through the fields test, and modified if needed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.139-142
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• 2002

An experimental model and a conceptual model are investigated in this paper with both shock tube experiment and numerical technique. The shock-vortex interaction generated by this model is visualized with various methods: holographic interferometry, shodowgraphy, and numerical computation. In terms of shock dynamics, there are two meaningful physics in the present problem. They are reflective wave from the slip layer at the vortex edge and transmitted shock penetrating the vortex core. The discussion in this study is mainly focused on the two kinds of waves contributing to the quadrupolar pressure distribution around the vortex center during the interaction.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.156-162
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• 2003

The shock absorber is a part having a direct influence on the ride comfort, stability and dynamic load prediction of a vehicle. Thus, a rationally modeled shock absorber should be required in the dynamic analysis of vehicles. This thesis presents a modified model, based on Worden's hyperbolic tangent function, in order to fit experimental data on the velocity-damping force of a shock absorber. The hyperbolic tangent function correctly indicates the characteristics of a shock absorber, and has the advantage of containing physical causality. To evaluate the method, comparative evaluations of the linear model, the 5th polynomial model and Worden's model were carried out. The function presented in this paper is not only simple but also makes it possible to estimate the function coefficients easily and visually. In addition, it has the advantage of containing physical causality. Lastly, it effectively models the damping force of a shock absorber.