• 한국수소및신에너지학회논문집
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• 제28권3호
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• pp.252-272
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• 2017

Fuel cell systems have to satisfy acceptable operating reliability, sufficient lifetime and price to enter the market in competition with existing products. Fuel cells are made up of complex element technologies and various problems related to the failure of the components can affect the reliability and safety of the system. This problem can be overcome by introducing a monitoring and supervisory control system in addition to automatic control to detect the failure of the fuel cell quickly and properly diagnose the performance degradation. For the fault detection and diagnosis of polymer electrolyte fuel cells, the model based method using the theoretical superposition value and the non-model based method of checking the signal tendency or the converted signal characteristic can be applied. The methods analyzed in this paper can contribute to the development of integrated monitoring and control technology for the whole system as well as the stack.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.847-858
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• 2015

Control strategy and corresponding parameters have significant impacts on the overall technical and economic characteristics of composite energy storage systems (CESS). A better control strategy and optimized control parameters can be used to improve the economic and technical characteristics of CESS, and determine the maximum power and stored energy capacity of CESS. A novel coordinated control strategy is proposed considering the coordination of various energy storage systems in CESS. To describe the degree of coordination, a new index, i.e. state of charge coordinated response margin of supercapacitor energy storage system, is presented. Based on the proposed control strategy and index, an optimization model was formulated to minimize the total equivalent cost in a given period for two purposes. The one is to obtain optimal control parameters of an existing CESS, and the other is to obtain the integrated optimal results of control parameters, maximum power and stored energy capacity for CESS in a given period. Case studies indicate that the developed index, control strategy and optimization model can be extensively applied to optimize the economic and technical characteristics of CESS. In addition, impacts of control parameters are discussed in detail.

• 한국통신학회논문지
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• 제32권4B호
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• pp.200-207
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• 2007

최근에 인터넷에서는 많은 Peer-to-Peer (P2P) 시스템이 등장하여 자료 공유가 활발히 이루어지고 있다. P2P 시스템은 자가 형성, 자가 치료, 분산처리와 같은 특징을 지니고 있어, 그러한 특징을 공유하는 애드혹 환경에서도 적절한 응용 프로그램으로 인식되고 있다. 본 논문은 가장 널리 사용되는 P2P 시스템중의 하나인 Gnutella를 애드혹 망에서 보다 효율적으로 동작할 수 있도록 개선하여 시스템 수명 연장, 오버헤드 감소, 향상된 성능을 제공하는 것을 목적으로 한다. 이를 위해 계층적 피어를 사용하는 Gnutella 방식에 계량값을 이용한 울트라피어 선택방안, 능동적 울트라피어 정보제공 방안 등을 도입하였다. 모의실험 결과, 본 논문에서 제안한 방안은 Gnutella 보다 망을 더욱 효율적으로 사용함으로써 검색 성공률을 높이고, 응답시간을 줄였으며, 오버헤드 측면에서도 훨씬 좋은 결과를 보였다. 또한 애드혹 망 및 P2P 시스템의 지속시간에 영향을 미칠 수 있는 노드들의 잔여 에너지양을 높일 수 있었다.

• 생물치료정신의학
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• 제24권3호
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• pp.129-141
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• 2018

Suicide is a behavior that is intended to cause death by itself and requires medical treatment, resulting in suicidal attempt or completion. Suicide causes loss of life, damages the body, costs a lot of medical expenses, and causes families to fall into sorrow and suffering therefore this suicide is a huge loss to family and society. There have been attempts to reduce and prevent suicide by understanding the mechanism of suicide. The mechanism of suicide can be thought of as psychological mechanism and biological mechanism. In the past, if we considered the psychological and biological mechanisms separately, the development of neuroscience now connects and integrates these two. Psychological factors affect biological factors and biological temperaments also affect perception or thinking about the situation and increase psychological vulnerability. Distant factors in suicidal behavior-such as childhood adversity and family and genetic predisposition-increase the lifetime risk of suicide. They alter the response to stress and other processes through changes in gene expression and regulation of emotional and behavioral characteristics. Distant factors affect the biological system and consequently changes in these systems can increase the risk of suicide. In other words, the distal factor does not directly induce suicidal behavior but rather acts indirectly through developmental or mediating factors. These mediating factors are impulsive aggressive and anxious trait, and chronic use of substances. The mechanism of this disorder is the abnormality of the serotonin system and the abnormality of the lipid level. Proximal factors are associated with the onset of suicide events and include changes in the major neurotransmitter systems, inflammatory changes, and dysfunction of glial cells in the brain. A series of studies, including a variety of research methods and postmortem and in-vivo imaging studies, show the impairment of the serotonergic neurotransmitter system and hypothalamic-pituitary-adrenal axis stress response system for suicidal behavior. These disorders lead to suicidal behavior due to difficulty in cognitive control of mood, pessimism, reactive aggression, abnormality in problem solving abilities, excessive response to negative social signals, severe emotional distress, and cognitive dysregulation of suicidal ideation.

• 한국기계가공학회지
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• 제18권2호
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• pp.65-72
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• 2019

In long freight trains, there is a brake time delay in neighboring freight cars, which causes damage and fractures in the couplers, especially at their knuckle. A problem in the couplers of the cars can cause derailment and damages of human life and property. In this study, maximum forces on the couplers are studied when a long freight car brakes with the brake delay time and coupler gap. We make a dynamic model of 50 freight cars and couplers, applying contact between the couplers and a characteristic curve to express the force and displacement of the buffers using SIMPACK, which is a multi-body dynamics program. We use EN 14531-2, which is a standard of freight car brakes, to verify the dynamic model. Then, we compare the analyzed impact force with the coupler knuckle standard after applying the two carriages of a locomotive in the model based on the dispersed double head control system. The result shows that all coupler gap conditions satisfy the infinite lifetime of the material when the brake delay time is 0.1 second.

• 한국구조물진단유지관리공학회 논문집
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• 제11권4호
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• pp.109-120
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• 2007

본 연구에서는 생애주기비용을 고려한 성능기반 최적 유지관리 전략 수립 시스템을 개발하였다. 교량 수명동안 비용과 성능이라는 상반되는 목적을 균형있게 만족시킬 수 있는 유지관리 시나리오의 생성을 다중목적 조합최적화 문제로 정식화하고 유전자알고리즘을 적용하였다. 개발된 프로그램을 이용하여 국도 상 강거더 교량의 최적 유지관리 시나리오를 제공하는 과정을 제시하였다. 개발된 시스템은 현재의 교량 유지관리 전략 수립의 방법을 개선하여 교량 관리주체에게 다양한 제약 및 요구조건에 부합하는 최적의 교량 유지관리 시나리오를 제공할 수 있는 효율적인 도구로 활용될 수 있을 것으로 판단된다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 추계학술대회
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• pp.26-33
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• 1995

Silicone Rubber (SR)-based potassium- and sodium-selective solid-state electrodes have been developed for the portable blood electrolyte analyzer system. The electrochemical performance of these electrodes have been evaluated with a static experimental setup and with the newly developed blood electrolyte analyzer system (model; HS603). It has been shown that their potentiometric properties are essentially comparable to those of PVC-based ion-selective electrodes, but with greatly improved lifetime (200 and 40 days for potassium and sodium sensors, respectively) and potential stability (within $\pm0.1$ mV). Clinical tests have been performed with real serum samples and the results have been compared with those obtained from Ciba-Corning BGA 288 system; correlations were excellent, proving its practical utility as a new commercial system.

• 한국한의학연구원논문집
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• 제6권1호
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• pp.13-27
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• 2000

1. Purpose: This study was intended to consider through a bibliographical comparison between the system of Kabo-Bon ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$ and that of Shinehook-Pan ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$. 2. Method: This study was based on the ${\ulcorner}$Hamsansachon Dongyi Soose Bowon old Kabo-Bon${\lrcorner}$, which was compared with a bibliographical data from Shinchook-Pan ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$ and the collection of manuscripts left unpublished in Lee Je-ma's lifetime. 3. Result & Conclusion: Exterior-Interior Pathological system was found in the system of Kabo-Bon ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$, and it might be referred to that of Jang Joong-kyung's ${\ulcorner}$Shanghan Ron${\lrcorner}$. There were no 'the Discourse on the Origin of oriental Medicine' and 'the Discourse on the General Health Maintenance' in the Kabo-Bon ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$. And it was supposed to be many changes of contents on 'the Discourse on Nature and Order', 'the Discourse on the Four Principles', 'the Discourse on the Establishment and Supplement' and 'the Discourse on Viscera and Bowels' in the Shinchook-Pan ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$ compared with those in the Kabo-Bon ${\ulcorner}$Dongyi Soose Bowon${\lrcorner}$.

• Journal of Welding and Joining
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• 제33권3호
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• pp.25-31
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• 2015

Due to environmental regulations (RoHS, WEEE and ELV) of the European Union, electronics and automotive electronics have to eliminate toxic substance from electronic devices and system. Specifically, reliability issue of lead-free solder joint have an increasing demand for the car electronics caused by ELV banning. The authors prepared engine control unit and cabin electronics soldered with Sn-3.0Ag-0.5Cu (SAC305). To compare with the degradation characteristics of solder joint strength, thermal cycling test (TC), power-thermal cycling test (PTC) and series tests were conducted. Series tests were conducted for TC and PTC combined stress test using the same sample in sequence and continuously. TC test was performed at $-40{\sim}125^{\circ}C$ and soak time 10 min for 1000 cycles. PTC test was applied by pulse power and full function conditions during 100 cycles. Combined stress test was tested in accordance with automotive company standard. Solder joint degradation was observed by optical microscopy and environment scanning electron microscopy (ESEM). In addition, to compare with deterioration of bond strength of quad flat package (QFP) and chip components, we have measured lead pull and shear strength. Based on the series test results, consequently, we have validated of series test method for lifetime and reliability of Pb-free solder joint in automotive electronics.

• 한국사회복지학
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• 제48권
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• pp.7-41
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• 2002

This paper analyses the proposals contained in the British Government Green Paper, A New Contract for Welfare: Partnership in Pensions for low paid workers and the potential of the new rules to guarantee a decent income in old age. The UK pension system is a partnership between the State(providing the basic state pension and the SERPS), employers(providing occupational pension scheme) and private pension providers(providing personal pensions). Although the system needs to change, this partnership remains the right foundation. However, the pension Green Paper proposes substantial changes to second tier pension provision in the UK. In particular, the Government plans to replace the SERPS with a new State Second Pension. According to the Green Paper, this will result in "dramatically better pension provision for those earning less than ${\pounds}9,000$ a year" and through increased payments to private pension schemes, will also provide "extra help to those on middle incomes(${\pounds}9,000-{\pounds}18,500$ a year). Therefore, it discusses the general principles inherent in the design of the British pension system and analyses the balance of these principles is represented in the Green Paper. The paper then examines how the Government's proposals protect individuals from a means-tested old age. This paper finds that the Green paper's proposals add up to reinventing a new two-stage basic pension. However, two key features of a such a basic pension package are missing- an 'adequate' level of payment and comprehensive entitlement. Because of these missing principles we argue that the Green Paper's proposals incorporate for the low paid. The income from the basic pension and the secondary pension which is so near the means-tested minimum that little is gained in retirement from a lifetime of work and contribution. Indeed, the shift away from collective provision and the emphasis on individual responsibility will reinforce this inequality, so that many poor will continue to experience poverty in later life.