• Title/Summary/Keyword: 강제가진

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Forced Convection in a Flow Channel with Multiple Obstacles (다수의 장애물을 가진 유동채널에서의 강제 대류에 관한 연구)

  • Nam, Pyung-Woo;Cho, Sung-Hwan
    • Solar Energy
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    • v.9 no.1
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    • pp.62-69
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    • 1989
  • This analysis is to investigate the influence of inflow angle when cooling air flows into PC (Printed Circuit) board channels. Flow between PC board channels with heat generating blocks is assumed laminar, incompressible, two-dimensional. Geometric parameters (block spacing (S), block height (H), block width (W) and channel height (L)) are held fixed. Inflow angle variations are $-10^{\circ},\;0^{\circ},\;10^{\circ}$, where uniform heat flux per unit axial length Q (W/m) from heated block surfaces is generated. The governing equations for velocity and temperature are solved by SIMPLE (Semi-Implicit Method Pressure for Linked Equation) algorithm. Nusselt number on each block surfaces is analyzed after a numerical calculation result. The result shows that the assumption on parallel inflow (inflow angle to channel, $0^{\circ}$) to PC board channels can be used without large error even when inflow' angle is varied.

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A Strategy for Improving TCP Performance Considering Handoff in Mobile Computing Environments (이동 컴퓨팅 환경에서 핸드오프를 고려한 TCP 성능 개선 방안)

  • 박종문;송주석
    • Proceedings of the Korean Information Science Society Conference
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    • 1999.10c
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    • pp.688-690
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    • 1999
  • 오늘날 통신 환경에서 널리 사용되고 있는 TCP는 유선망과 고정된 호스트로 이루어진 전통적인 네트워크에 적합하여 유선망의 특성을 적용한 것이기 때문에, 무선 구간의 제한된 대역폭, 높은 지연, 산발적인 비트 에러, 일시적인 연결 두절 및 핸드오프 등과 같은 특징을 가진 특성상 유선망과는 상이한 무선망에 이를 그대로 적용하게 되면 오히려 불필요한 메커니즘의 호출로 인해 End-to-End Throughput의 성능 저하를 가져온다. 이러한 무선망에서 발생되는 핸드오프로 인해 TCP 성능이 저하되는 것을 방지하기 위한 방안으로 핸드오프 과정 동안 무선 구간에서 발생되는 패킷 손실로 인한 고정 호스트 재전송 타이머의 타임아웃과 불필요한 혼잡제어 절차의 수행에 따른 성능감소를 미연에 방지하기 위한 방안으로 핸드오프가 발생했을 때 핸드오프를 가장 먼저 알게 되는 이동 호스트가 ICMP(Internet Control Message Protocol) 형태의 EHN(Explicit Handoff Notification) 패킷을 고정 호스트에 전송하여 새로운 기지국과 고정 호스트에 핸드오프의 시작을 명시적으로 알림으로써 핸드오프 과정 동안에 발생되는 고정 호스트 재전송 타이머의 타임아웃과 혼잡제어 절차를 강제로 일어나지 않게 하여 기지국에서의 부하를 감소하게 할 수 있는 새로운 방식의 EHN 알고리즘을 제안한다.

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Comparative Analysis on the Measures and Programs for Age Equality of OECD Countries (OECD 국가의 연령차별 완화대책 및 프로그램 비교연구: 노동시장에서의 연령차별금지법을 중심으로)

  • Han, Hye-Kyung
    • Korean Journal of Social Welfare
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    • v.57 no.2
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    • pp.277-295
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    • 2005
  • The purpose of this study was to bring together evidence of the operation and impact of legislation to prohibit age discrimination in those countries that have such laws. We identified 5 countries with extensive age discrimination legislation: the US, Canada, Australia, Finland and Republic of Ireland. The objectives and cultural context of age discrimination lesgislation, which plays a large part in each country determining what type of lesgislation is deemed to be appropriate. The effeciveness or impact of the legislation, in terms of progress towards these objectives. Some key issues where choices of emphasis will need to be made in the introduction of new legislation to reduce age discrimination.

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A Study on the Pressure Vessel containing tension material used the Prestressed Concept (프리스트레스트 개념을 적용한 긴장재가 구비된 압력용기 연구)

  • Yim, Heon-Wook
    • Journal of Convergence for Information Technology
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    • v.7 no.5
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    • pp.103-109
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    • 2017
  • A pressure vessel is a cylindrical container that accommodates a pressurized fluid. In real life, there are propane canisters and butane canisters. According to data from the Korea Gas Safety Corporation, The number of domestic gas accidents is average 33 cases of domestic gas accidents occurred per year and 20.8 for mobile butane gases. The purpose of this study was to investigate a method to prevent this kind of explosion. Common studies include forced drain through safe holes, forced separation of butane canisters, and manufacturing of high-strength steel. This paper uses a concept that reduces stress inside the cylinder using prestressed method that precede compression. In other words, install a long liner in both ends of the pressure vessel. I want to develop a safety device that acts like a gas intermediate valve.

Low frequency critical bandwidths of Korean normal hearing adults (한국 정상 성인의 저주파수 임계 주파수 대역 특성에 관한 연구)

  • Moon, Jihyun;Jeon, Kyongeon;Lim, Dukhwan
    • The Journal of the Acoustical Society of Korea
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    • v.41 no.1
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    • pp.70-75
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    • 2022
  • The critical bandwidth represents response interactions with respect to a signal tone and their neighboring bands. This study was to analyze the critical bandwidths of a clinically important 500 Hz tone in Korean young male and female subjects (male = 10, female = 10) at a conversational level (60 dB HL). Data were measured with notched band noise and two alternative forced choice methods. Results showed that the critical bandwidth was slightly greater (95 Hz) than the previous Western measures. There were no statistically significant differences in gender, nor were there any significant differences in lateralization of the ear (p > 0.05). These results may have implications in optimizing effective tinnitus masking or the related clinical applications.

A study on mandatory insurance for aircraft operators (항공보험 가입의무에 관한 연구)

  • Lee, Chang-Jae
    • The Korean Journal of Air & Space Law and Policy
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    • v.33 no.2
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    • pp.169-197
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    • 2018
  • The purpose of this study is to present a reasonable and concrete standard for the Korean aviation insurance compulsory subscription system. Through this, we aim to improve the current revision of laws and regulations, and ultimately create an environment in which the safety and property of the Korean people who use aircraft with appropriate aviation insurance can be secured. In particular, by reviewing the aviation business law and its new laws and regulations enacted in 2017, the legislative improvement direction of aviation insurance will be proposed. In order to maintain the continuous growth of the air transportation industry and to make amicable compensation for the victims, considering the characteristics of the total accident, instantness, and giganticness of air accidents in which a lot of people and property are lost in the event of an accident, adequate insurance coverage is essential. In this respect, the compulsory insurance to amend the principle of freedom of contract, which is the great principle of the modern judicial system, will be persuasive. However, in comparison with foreign legislation, the legal provisions on Korea's obligation to comply with aviation insurance need to be revised around the following issues: First, it is reasonable to enforce the regulation of the mandatory aviation insurance by legislation from the Congress not by administrative regulations. Because it will force the monetary obligations of the individual such as common air carriers. Second, our law regulations respond to various kinds of air damages by using the phrase "limit of liability stipulated in international conventions". However, as we have seen in the text, the range of compensation are various according to the use of legal instruments in international conventions such as the Montreal Convention, which governs the compensation of passengers for damages to passengers today. Third, in countries with narrow territories, such as Korea, there are big differences in flying time and insurable risk between domestic and international transportation. Therefore, it is necessary to divide domestic transportation and international transportation even in the obligation to join the insurance. This dual discipline has the advantage for rookies in air carrier market who mainly start their business from domestic service. Fourth, according to Korean law, the regulations of automobile loss insurance is applicable to the aviation mandatory insurance of unmanned aerial vehicle accident which is lack of persuasion. In the future, it will be appropriate to discipline insurance for unmanned aerial vehicles with unlimited potential for development from a long-term perspective.

Nonlinear Analysis of a Forced Beam with Internal Resonances (내부공진을 가진 보의 비선형 강제진동해석)

  • 이원경;소강영
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1991.04a
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    • pp.147-152
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    • 1991
  • 양단이 고정된 보가 변형할 때에는 중간 평면의 신장을 수반하게 된다. 운동 의 진폭이 증가함에 따라 이 신장이 보의 동적 응답에 미치는 영향은 심각 하게 된다. 이러한 현상은 응력과 변형도와의 관계가 선형적이라 하더라도 변형도와 변위와의 관계식은 비선형이 되며 결국은 보의 비선형 운동방정식 을 낳게된다. 보는 연속계이긴하지만 근사를 위하여 다자유도계로 간주할 수 있다. 비선형 다자유도계에 있어서는 선형화된 계의 고유진동수끼리 적절한 관계를 가질 때 내부공진이 발생할 수 있다. 양단이 고정된 곧은 보의 비선 형 동적응답이 그동안 많이 연구되어 오고 있으며, 집중질량을 가지고 직각 으로 굽은 보의 해석을 위하여 내부공진을 고려한 해석적 혹은 실험적 연구 가 이루어져 왔다. 그중에서도 Nayfeh등은 조화가진 하의 핀과 꺾쇠로 고정 된(hinged-clamped) 보의 정상상태응답을 해석하기 위해 두 모우드 사이의 내부공진을 고려하였다. 이 연구에서는 세 모우드 사이의 내부공진을 고려하 여 강제진행 중인 보의 비선형 해석을 다루고자 한다. 이 문제에 관심을 갖 게 된 동기는 "연속계의 비선형 해석에서 더 많은 모우드를 포함시키면 어 떤 결과를 낳게 될 것인가\ulcorner"라는 질문에서 생겨난 것이다. 갤러킨 법을 이용 하여 비선형 편미분 방정식과 경계 조건으로 표현되는 이 문제를 연립 비선 형 상미분 방정식으로 변환한다. 다중시간법(the method of multiple scales) 을 이용하여 이 상미분 방정식을 정상상태에서의 세 모우드의 진폭과 위상 에 대한 연립비선형 대수방정식으로 변환한다. 이 대수방정식을 수치적으로 풀어서 정상상태 응답을 구하고 Nayfeh등의 결과와 비교한다. 결과와 비교한다. studies, the origin of ${\alpha}$$_1$peak was attributed to the detrapping process form trap with 2.88[eV] deep of injected space charge from the chathode in the crystaline regions. The origin of ${\alpha}$$_2$ peak was regarded as the detrapping process of ions trapped with 0.9[eV] deep originated from impurity-ion remained in the specimen during production process of the material, in the crystalline regions. The origin of ${\beta}$ peak was concluded to be due to the depolarization process of "C=0"dipole with the activation energy of 0.75[eV] in the amorphous regions. The origin of ${\gamma}$ peak was responsible to the process combined with the depolarization of "CH$_3$", chain segment, with the activation energy of carriers from the shallow trap with 0.4[eV], in he amorp

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Antifatigue Effect of Chlorella vulgaris in Mice (클로렐라의 항 피로 효과 연구)

  • An Hyo-Jin;Seo Sang-Wan;Sim Kyung-Sik;Kim Jung-Suk;Kim Eun-Hee;Lee Mi-Ok;Park Hyeung-Suk;Han Jae-Gab;Lee Eun-Hee;Um Jae-Young;Hong Seung-Heon;Kim Hyung-Min
    • The Korean Journal of Food And Nutrition
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    • v.19 no.2
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    • pp.169-175
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    • 2006
  • A unicellular algae, Chlorella vulgaris(CV), was used as a biological response modifier. The effect of CV on forced swimming test and blood biochemical parameters related to fatigue was investigated. Blood urea nitrogen(BUN); creatine kinase(CK); lactic dehydrogenase(LDH); glucose(Glc); total protein(TP); and albumin were determined. CV was orally administered to mice in the range of 0.05 to 0.15 g/kg/day. A forced swimming test results on 3 and 7 day after administration of CV, showed that immobility time was decreased in the CV-administered group(0.15 g/kg). In addition, the contents of BUN in the blood serum were decreased in CV-fed group. The contents of CK and LDH were tended to decrease, but not statistically significant. The plasma Glc level was increased in CV-fed groups(0.05 and 0.1 g/kg) compared to control group. It had no effect on the elevation of TP and albumin level. The results indicate that CV could improve physical stamina.

The review of the 2016 amended Korean Mental Health promotion Act from the Perspective of Human Rights and Inclusion of Persons with Mental Disabilities (정신장애인의 인권과 지역사회통합의 관점에서 본 2016년 정신건강증진법의 평가와 과제)

  • Park, Inhwan
    • The Korean Society of Law and Medicine
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    • v.17 no.1
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    • pp.209-279
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    • 2016
  • The Korean Mental Health Act was amended 2016 overall. This paper examines and evaluates the old Korean Mental Health Act since 1995 and the new Korean Mental Health Promotion Act 2016 from the Perspective of Human Rights and Inclusion of Persons with Psychosocial Disabilities. The persons with mental disabilities was separated and ruled out from society by the enactment of the Mental Health Act in 1995 and five times amendment. That has been justified and institutionally supported by medical viewpoint. The medical approach which reconsider the persons with mental disabilities as patients conceal that the aims of the involuntary admission in Mental Hospital are protection of society and the relief of the family member's duty of support for person with mental disabilities. This is institutionally supported in the 1995 Korean Mental Health Act by involuntary admission through the consent of family members as protectors. According to the old Act, the family members as protectors are authorized to consent to involuntary admission of persons with mental disabilities. Also, the psychiatrist that diagnoses the person with mental disabilities and evaluates the need for treatment by admission is not impartial in this decision. Family members as protectors may want to lighten their burden of support for the person with mental disabilities in their home by admitting them into a mental hospital, and the psychiatrist in the mental hospital can be improperly influenced by demand of hospital management. Additionally, Article 24 of the Korean Mental Health Act for the Involuntary Admission by the Consent of Family Members as Protector might violate personal liberty, as guaranteed in the Korean Constitution. The Mental Health Promotion Law was amended to reduce the scope of the persons with mental illness which are subject to forced hospitalization and to demand that a second diagnosis is made by another psychiatrist and screening by the committee concerning the legitimacy of admission in the process of the involuntary admission by the consent of family members as a method of protection. The amended Mental Health Promotion Law will contribute to reducing the number of the involuntary admissions and the inclusion of persons with mental disabilities. But if persons with mental disabilities are not providing some kind of service to the community, the amended Mental Health Promotion Law does not work for Inclusion of them.

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Analysis of Experimental Modal Properties of an Electric Cabinet via a Forced Vibration Test Using a Shaker (가진기를 이용한 강제진동시험에 의한 전기 캐비닛의 실험적 모드특성 분석)

  • Cho, Sung-Gook;So, Gi-Hwan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.15 no.6
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    • pp.11-18
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    • 2011
  • Accurate modal identification analysis is required to reasonably perform a seismic qualification of safety-related electric equipment installed in nuclear power plants (NPPs). This study evaluates a variation of the modal properties of an electric equipment cabinet structure in NPPs according to the excitation levels. For the study, an actual electric equipment cabinet was selected as a specimen and was dynamically tested by using a portable exciter in accordance with the level of input vibration energy. Tests were classified into two sets: with-door cases, and without-door cases. Frequency response functions were computed from the signals of the acceleration responses and input motions measured from the vibration tests. A polynomial curve fitting algorithm was used to extract the modal properties from the frequency response functions. This study reviews the variation of the modal properties according to the variation of the excitation levels. The results of the study show that the modal frequencies and the modal dampings of the object specimen varies nonlinearly according to the excitation level of the test motion. Attaching the door increases the modal damping of the cabinet.