• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.58-60
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• 2005

This paper presents a optimal power flow calculation algorithm considering voltage and transient stability. In this method, voltage stability margin and transient stability constraints is incorporated into a optimal power flow calculation formulation to guarantee adequate voltage and transient security levels in power system. The proposed method is applied to IEEE-24 Reliability Test System and the results shows the effectiveness of the method.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2007년도 추계학술대회
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• pp.109-113
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• 2007

Micro-PIV is a well-known method for measurement of two- dimensional, two-component velocity in the microfluidic devices. Lots of the micro fluidic devices generate three-dimensional flow and 3D measurement of velocity is helpful to understand the physics of micro flow phenomena. In this study, we developed new micro 3D measurement method by applying 2-frame PTV in stereoscopic micro system. In this study, we did the validation study of SMPTV by using the simulated flow model to verify the accuracy and the feasibility of measurement and compared with SMPIV method. The results showed that SMPTV provides better spatial resolution and measurement accuracy than SMPIV method.

• 동력기계공학회지
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• 제10권2호
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• pp.68-74
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• 2006

In the development of new automobiles, the efforts to reduce environmental problems like air pollution have been risen. Blowby gas consists of about $20{\sim}35%$ of total amount of Hydrocarbon (HC), one of dangerous pollutants issuing from automobiles. A PCV valve is a very small component in an automotive engine but it is a very important part. Because that a PCV valve is used to control blowby gas and to recirculate it into a manifold automatically. Although it has very simple operating principle, designing a PCV valve is so difficult due to interaction between fluid and solid. In this study, our purpose is to develop a design program for a PCV valve and to verify its efficiency. Both Bernoulli equation and 4th order Runge-Kutta method were adopted to predict spool displacements and flow patterns. Comparing with experiments, it was found that both spool diameters and displacements were predicted well, however, flow rates showed a little differences because of the assumption of non viscous flow.

• 한국산업정보학회논문지
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• 제5권4호
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• pp.39-46
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• 2000

New products often have in-service reliability problem despite an intensive development program. Therefore reliability data must be collected and analyzed, and improvements designed and implemented. A type of reliability incentive contract which has recently attracted a lot of attention is reliability improvement warranty(RIW). It has been employed by military, airlines, telecommunication systems, and public utilities. An RIW contract requires that the supplies carries out all repairs, modify the equipment to improve its reliability, and provides all spates needed, for a fixed period, for once-off fee. This paper presents the reliability growth analysis and management methods for in-service MC68 microprocessor, which is the main component of the base station controller in PCS(Personal Communication Service) telecommunication system. The methods will provide guidelines to monitor reliability program in planning RIW contract.

• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.7431-7434
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• 2015

As an important component of innate immune system, neutrophil has been involved in many other physiological processes, including tumor-related diseases. In 2004, the phenomenon of NETs was reported for the first time. Extracellular decondensed chromatin, released from activated neutrophils, forms a network structure, which is NETs. This review focuses on the function of NETs in tumor cell proliferation, metastasis, and tumor-associated thrombosis; it also explores the application of NETs specific markers in the diagnosis of pre-thrombotic state and tumor associated diseases; it also explores NETs inhibitor for the treatment of tumor-related diseases. In view of the rapid development of NETs, it may provide new therapeutic targets for tumor-associated thrombosis, and even tumor itself.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권1호
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• pp.28-37
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• 2017

Purpose: This paper proposes a procedure that may infer and identify interaction failures in a module. Methods: In design FMEA, we defined an interaction model between components and proposed a method for selecting a single component by using the standard specification classification table and four methods for choosing the related components. We also introduced the function tree for function and requirement characteristic analysis and proposed utilization of standard stress lists and 1st and 2nd stress analysis tables to determine the effect the stress analysis has on interactions. Finally, the interaction mechanism diagram was proposed and used to infer the failure mechanism. Process FMEA also established procedures in a similar way. Results: We established a procedure for predicting the failure mode due to interaction between components based on Company A's multi-step FMEA procedure. Conclusion: By applying the proposed interaction FMEA procedure to the development model, we were able to confirm the effect of the new derivation on the failure mode of interaction, which was not predicted by the existing FMEA.

• 생약학회지
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• 제8권2호
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• pp.69-72
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• 1977

The investigation is involved with the development of the new method of decoction preparation in order to prevent the loss of volatile oil from crude drugs. Volatile oil in crude drug containig volatile oil ranged from 1 to 2.2% in content. Volatile oil content in crude drung prescription which main component is a crude drug containing volatile oil was $0.11{\sim}0.39\;ml$. It was found that traditional method of decoction preparation has caused to lose almost all of the volatile oil. Application of method of Pharmacopoea (Kp II) for the preparation of decoction prevented the loss of volatile oil from one half to two-third of its content. The method of Pharmacopoea to which air condenser was attached could completely prevented the loss of volatile oil from the preparation.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 the technical trends in the world automobile and lubricant market
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• pp.21-24
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• 2002

There is a trend with driveline lubricants toward improved thermal stability, vehicle component durability and fuel efficiency. These improvements can significantly reduce vehicle operating costs and improve customer satisfaction. Of these improvements, the fuel efficiency is getting a substantial attention due to recent focus on $CO_2$ emission control in Europe, Japan and $CAF{\'{E}}$ requirement in U.S.A. Lower viscosity axle oils and transmission fluids are currently being evaluated as potential solutions since these lubricants tend to reduce the churning losses and can improve the fuel efficiency. However, these lubricants should provide adequate gear and bearing protection, while increasing the overall efficiency of the driveline components. In this paper, the development of new fuel efficient axle was discussed with the focus on the effect of base oils, additives, and viscosity modifiers on the fuel efficiency of driveline components.

• 한국해양공학회지
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• 제34권2호
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• pp.120-127
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• 2020

Evaluation of fatigue strength considering the springing effect of very large container ships is crucial in the design stage. In this study, we established a fatigue strength evaluation method considering a linear springing component in the frequency domain. Based on a three-dimensional global model, a fluid-structure interaction analysis was performed and the modal superposition method was applied to determine the hot spot stress at the hatch corner of very large container ships. Fatigue damage was directly estimated using the stress transfer function with a linear springing response. Furthermore, we proposed a new methodology to apply the springing effect to fatigue damage using hull girder loads. Subsequently, we estimated the fatigue damage contribution due to linear springing components along the ship length. Finally, we discussed the practical application of the proposed methods.

• 대한기계학회논문집A
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• 제29권7호
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• pp.947-954
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• 2005

The purpose of this study is to develop failure pressure evaluation models, which are applicable to straight pipes and elbows containing an internally wall thinning defect induced by flow-accelerated-corrosion (FAC). In this study, thus, three dimensional finite element (FE) analyses are performed to investigate the dependences of failure pressure of internally wall thinned pipe on the defect shape, the pipe geometry, and the defect location and bend radius of elbow. Also, the existing failure pressure assessment models for externally wall thinned pipes are examined. Based on these, the new models for assessing failure pressure of piping components with an internally wall thinning defect are proposed. Comparison of failure pressure, predicted by proposed models, with FE analysis result shows good agreement regardless of pipe type, defect shape, and defect location and bend radius.