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소수주형 철도교의 궤도시스템 변화에 따른 동적거동 분석 (A Dynamic Behavior Analysis of composite Few Plate Girder Railway Bridge under Variety of Track systems)

  • 이홍준;최정열;엄맥;박용걸
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2005년도 추계학술대회 논문집
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    • pp.1171-1176
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    • 2005
  • The latest technical development of steel plate girder railway bridge are developing in ways to maximize its durability of materials in use of high strength steel and efficiency of maintenance and management by the introduction of simplified and standardization ideas. In addition to this, it is also expected to reduce the cost of bridge construction and to simplify the process of bridge manufacturing. Referring to this, composite few plate girder railway bridge is highly recommendable that is very economical with the fine exterior. In this paper, it will analyse the variation of dynamic behavior of existing composite few plate girder railway bridge with ballast caused by modified Slab Track through interpretation of limited enzyme in order to obtain the existing data for improvement of Slab Track system from Ballast Track system. Consequently, it can help maximize economic efficiency and structural capability. As a results, although the natural frequency by modified Slab Track are decreased, it is hardly influencing on the safety of railway bridges. It is also evident in the case of slab deck with a reduced scale in comparison with Ballast Track. Therefore, it is expected to reduce the cost of a railway bridge plan. And, it can expect the synergistic effect of the ensure long term durability of bridge caused by decreased stresses of bottom flange due to reduced dead load. As a result, the analytical study are carried out to investigate the composite few plate girder railway bridge could be the optimal design method for the dynamic safety of a girder section.

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우리나라 건축물에 사용된 목재 수종의 변천 (Changes in the Species of Woods Used for Korean Ancient and Historic Architectures)

  • 박원규;이광희
    • 건축역사연구
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    • 제16권1호
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    • pp.9-28
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    • 2007
  • We investigated the changes in the species of the woods used for Korean ancient and historic architectures, which include prehistoric excavated relics and existing wooden buildings in South Korea. The species data were collected from various sources such as excavation and repair reports, journal papers, and a few unpublished documents. We divided the building Periods as Paleolithic, Neolitic, Bronze Ages, Iron Age/Three Kingdoms, Koryo, Joseon (early, middle, late) and modem periods. In prehistoric periods, hardwoods were major species. Oak (Quercus spp.) woods dominated (94 percent in average); the others (5%) were Juglans mandshurica, Platycarya strobilacea, Castanea crenata, and few softwoods(1%). During Iron Age and Three Kingdom periods, oaks remained as a major species (57%) and others Platycarya strobilacea(21%), Castanea crenata(13%), and Pinus spp. (6%). The oak woods decreased in Koryo period and they occupied only 1.1%. Instead of oaks, pine (Pinus spp., 71%) and Zelkova serrata (22%) dominated in Koryo. In early and middle Joseon periods, pine woods (73%) remain as a major species and the others were oaks (14%) and Zelkova serrata (9%). As late Joseon came, the pine woods occupied more than 88%. In the late 19th and early 20th centuries, a few boreal species such as larch (Larix spp.) and spruce (Picea spp.), which grow in cold area, were found. We believe they were transported from northern Korea. The existing buildings in Korea are mainly from Joseon period and a few from late Koryo periods. During these periods, pine woods were used for most buildings. For such reason, pine woods were known as 'representative materials for historic buildings'. but earlier times, broad-leaved trees, i.e., oak and Zelkova woods were major materials. The changes in building materials resulted from both climate and human impacts. The dry climate and disturbed forests induce more pines in the mountains. We also compared the wood qualities of the species and found that Zelkova woods were superior ones and deserved more planting for future demands in the repair for historic buildings.

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Analysis of Auxiliary Device in a Gas-solid Cyclone by Experimental and Computational Approaches

  • Lee, Ju-Yeol;Park, Duck-Shin;Jo, Young-Min
    • Journal of Korean Society for Atmospheric Environment
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    • 제19권E1호
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    • pp.21-28
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    • 2003
  • An auxiliary device, called Post Cyclone (PoC). had been introduced and primarily examined in earlier works which proved the reduction of the emission of fine dust from the gas-solid cyclones without incurring significant increase of cost and pressure drop. It has been known that the PoC has some advantages over other secondary dust treatment devices such as (a) simple design, (b) low cost of manufacture, (c) minimum additional pressure drop, (d) high recoverbility of the product dust, and (e) simplicity of operation. Despite the potential advantage, however, lack of practical data confined its plausible application in wide areas. Thus, in this work, a few serial experiments were conducted in terms of a few operation conditions, and the particle trajectories throughout the cyclone set-up were visually analyzed by using a commercial computer simulation program (FLUENT).

Electrical breakdown properties in neon gas mixed with xenon

  • Han S. Uhm;Park, Eun H.;Guansup Cho;Ki W. Whang
    • Journal of Korean Vacuum Science & Technology
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    • 제4권4호
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    • pp.112-121
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    • 2000
  • The paper investigates electrical discharge properties in neon gas mixed with xenon. The breakdown temperature T$\sub$b/ and voltage V$\sub$b/ are obtained in terms of the gas mixture ratio X. It is shown that the breakdown voltage decreases, reaches the minimum value at X=0.02 and then increases again, as the mixture ratio X increases from zero to unity. Therefore, mixing the neon gas with a few percent of xenon is the most beneficial to reduce the breakdown voltage. Plasma density at breakdown in neon gas mixed with xenon is described in terms of the gas mixture ratio. The optimum value of mixture ratio for highest plasma density is found to be Xm=0.03. A preliminary experiment of AC-PDP is carried out for neon gas mixed with a few percent of xenon to verify some of the theoretical models. The experimental data agree qualitatively well with theoretical predictions.

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여고생(16~18세)의 체형분류(제1보);정면체형 분류 (Classification of high school girls' body shapes (Part I) -classificationi of frontal body shapes-)

  • 장혜경;김인숙
    • 한국의류학회지
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    • 제23권6호
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    • pp.876-885
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    • 1999
  • This study aimed to classify high school girls' frontal body shapes into a few representative types and to give each type a name to symbolize its typical shape clearly. Subjects consisted of 205 high school girls aged 15 through 17 years attending high schools in Kwangju. 55 anthropometric and 29 photographic measurements were taken from each subject. The data were reduced to a few factors and the main factors composing the frontal body shapes were classified into 3 clusters. as the results the frontal body shapes of the high school girls were classified into H, X, Y types.

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The Development of Mobile USB Home Control System

  • Kim, Hee-Sun;Kim, Yong-Seok;Lee, Chang-Goo
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.2155-2158
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    • 2003
  • A term of home automation that was in fashion only a few years ago has not been used any more. Nowadays, We have been used a term of home network or digital home than home automation much. While internet infra is diffused at home, data network corp., communication corp., electric appliance corp. and home automation control system corp. which we did not mind each other particularly constructed consortium, and they have designs on home network market. Also, cellular phone's growth tried home networking by using not only wired internet but also broadband wireless communication. Regardless, many solutions are coming out it is few to be applied to real life because the standard is not determined with the protocol each other. Therefore, we developed home network system using USB(Universal Serial Bus) that has the possibility most in home networking standard. The mobile USB home control system is excellent at expansibility and portability. Also we can complete low cost and stable system using an embedded system.

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피로균열 성장과정에 대한 평가방법의 영향 (Influence of Evaluation Methods for Fatigue Crack Growth Process)

  • 안철봉
    • 한국생산제조학회지
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    • 제8권1호
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    • pp.119-125
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    • 1999
  • The distribution of fatigue crack growth rate is subjected to the measuring interval and calculated method of growth rate. In this paper, in order to establish the method of determining the distribution of fatigue crack growth rate, which ignores those influences, a series of fatigue crack growth experiments and measuring intervals of crack length calculated reasonable are presented. The main conclusions obtained are summarized as follows: 1) As a result of the ΔP constant test and ΔK constant test, it is thought that an approximate measuring interval of 0.3~0.7mm is reasonable, which allows for few errors and is little subjected to the calculated method of crack growth rate. 2) After generally comparing the error estimation by using the experimental data of CCT specimen with the error rating of the CT specimens, it is possible that the fatigue test has few errors within the measuring interval, ξ(Δa/W)=0.0067~0.017, regardless of the dimension of specimen geometry.

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칼만 필터를 이용한 레이저 간섭계의 측정 정밀도 향상에 관한 연구 (A Study on the Improvement of Measurement Accuracy of Laser Interferometer using the Kalman filter)

  • 이재호;박태동;정준흥;박기헌
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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    • pp.1783-1784
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    • 2006
  • A laser interferometer is the unique measurement device that can measure the range up to a few meters with sub-nano resolution and this characteristic makes it as the important sensing device for the emerging nano-mechatronics technologies. The laser interferometer, however, is very sensitive to the environments such as temperature, humidity, sound noises, vibrations and air turbulences and these factors result in a few hundred nano meter errors. There have been many efforts to reduce these environmental errors. The output of the laser interferometer is assumed to be the sum of a real displacement and a Markov process noise. The purpose of this paper is to develop Kalman filter algorithms to reduce the laser interferometer measurement errors by exploiting the information of displacements in position-servo systems.

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지방자치단체의 다문화 가족정책 비교분석 (The Local Government Analysis of Muticultural Family Policy)

  • 강기정;변미희
    • 가족자원경영과 정책
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    • 제14권3호
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    • pp.37-51
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    • 2010
  • The purpose of this study was to analyze the local government of multicultural family policy. For this study, researchers first compared Canada, Australia and Japan and, second, analyzed the foreign policy plan data in Korea. The findings were as follows: First, Gyunggi province had many plans for foreign laborers and Gangwon, Kyungbuk and Jeonnam provinces had many plans for multicultural family wives. Second, many local governments had few economic independence programs for multicultural family wives, except Gangwon and Kyungbuk provinces. Third, many local governments had no school or study programs for children of multicultural families, except Gangwon, Kyungbuk and Chungnam provinces. Fourth, Canada and Australia had many sources of public information and many educational opportunities for people to gain understanding but local Korean governments had few of these programs. Finally, Canada and Australia had many international programs for immigrants to maintenance their culture but local Korean governments have none of these programs.

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A Mediating Effect of Internalization on Technology Adoption

  • Kim, Sung Kun
    • Journal of Information Technology Applications and Management
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    • 제23권3호
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    • pp.35-47
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    • 2016
  • Many technology innovations fail. Only a few of them are successfully implemented. Most of the remaining are discontinued before long or fail to be routinized. Although employees attempted to adopt the innovation for some legitimacy reasons, they have not reached the stage of internalization in which they believe in the real value of the innovation and become committed to the innovation. The deficiency of internalization was utilized in many studies as an important factor for explaining the failed innovation cases. However, few empirical studies examine the role of internalization in technology adoption. This study aims to investigate a mediating effect of internalization on technology adoption.