• Steel and Composite Structures
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• v.42 no.4
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• pp.459-475
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• 2022

In this paper a model for the prediction of the ultimate axial compressive capacity of square and rectangular Concrete Filled Steel Tubes, based on an Artificial Neural Network modeling procedure is presented. The model is trained and tested using an experimental database, compiled for this reason from the literature that amounts to 1193 specimens, including long, thin-walled and high-strength ones. The proposed model was selected as the optimum from a plethora of alternatives, employing different activation functions in the context of Artificial Neural Network technique. The performance of the developed model was compared against existing methodologies from design codes and from proposals in the literature, employing several performance indices. It was found that the proposed model achieves remarkably improved predictions of the ultimate axial load.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.3
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• pp.185-189
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• 2005

Lipids such as total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C) and high sensitivity C-reactive protein (hs-CRP) are known as good risk factors for coronary artery diseases caused by arthrosclerosis. We measured the serum concentrations of hs-CRP, TC, and HDL-C of 6,128 persons who underwent medical examinations in the Health Screening Center at Kangbuk Samsung Hospital. We classified the subjects into normotensive and hypertensive groups according to the blood pressure measured. We investigated whether there was a difference of hs-CRP and lipids between the normotensive and hypertensive groups. There was significant difference of TC, TC/HDL-C ratio, and hs-CRP concentration between the normotensive and hypertensive groups in both men and women, but there was no significant difference of HDL-C concentration between two groups. Our results indicated that the concentrations of hs-CRP and lipids were higher in patients with hypertension and confirmed the usefulness of lipids and hs-CRP in predicting the risk for coronary artery diseases.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1613-1616
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• 2008

Hiroshima University opened the advanced display laboratory (ADL) in 2006 to specifically focus on the PDP researches. The mission of ADL is to lay the bases for the innovative PDP technologies. Our research efforts have been concentrated on the fundamental study of protective materials and phosphors, and also of the effect of protective materials with high $\gamma$ emission in the high luminous efficacy. This paper briefly introduces the present status of our research activities.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.505-509
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• 2007

Proxy Mobile IPv6 (PMIPv6)는 Mobile Node (MN)가 스스로 이동성을 지원하지 않더라도 Mobile Access Gate가 MN대신 이동성을 처리하여 IPv6 이동성을 지원하는 기술이다. 좀 더 향상된 핸드오버 성능을 얻기 위해 Proxy Mobile IPv6에서도 버퍼링을 통한 패킷 손실을 줄이는 기법을 사용할 수 있다. 하지만, IEEE 802.11 네트워크에서는 Handover 발생 직전에 MN이 어떠한 통보도 AP로 하지 않기 때문에 Handover시에 패킷 손실을 줄이기 위한 패킷 버퍼링 방법을 사용하기가 어렵다. 본 논문에서 PMIPv6에서 MAG와 AP가 MN의 이동성을 감지하여 버퍼링을 시작하고 Handover가 발생하였을 경우에 대비해 버퍼링을 하는 Cross-layer 버퍼링 방법을 제안한다. 이를 통해 PMIPv6에서도 MN의 변경 없이 Handover시에 발생하는 패킷 손실을 최소화 할 수 있다. 또한 간단한 성능 비교를 통하여 제안 방법이 기존 PMIPv6보다 우수함을 알 수 있다.

• Nuclear Engineering and Technology
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• v.52 no.1
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• pp.148-154
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• 2020

The radiation induced segregation of Cr at grain boundaries (GBs) in Ferritic/Martensitic steels was modeled assuming vacancy and interstitialcy diffusion mechanisms. In particular, the dependence of segregation on temperature and grain boundary misorientation angle was analyzed. It is found that Cr enriches at grain boundaries at low temperatures primarily through the interstitialcy mechanism while depletes at high temperatures predominantly through the vacancy mechanism. There is a crossover from Cr enrichment to depletion at an intermediate temperature where the Cr:Fe vacancy and interstitialcy diffusion coefficient ratios intersect. The bell-shape Cr enrichment response is attributed to the decreasing void sinks inside the grains as temperature rises. It is also shown that low angle grain boundaries (LAGBs) and special Σ coincidence-site lattice (CSL) grain boundaries exhibit suppressed radiation induced segregation (RIS) response while high angle grain boundaries (HAGBs) have high RIS segregation. This different behavior is attributed to the variations in dislocation density at different grain boundaries.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.1047-1050
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• 1998

This paper describes an advanced prototype of voltage-fed zero voltage soft-switching PWM resonant inverter with an active voltage clamped capacitor, which is put into practice for high-frequency high-power induction-heated appliances. This application-specific quasi-resonant inverter using the latest generation IGBTs for soft-switching can regulate its output power under a principle of a fixed frequency ZVS-PWM strategy. Its operating principle and unique features are presented as compared with a conventional quasi-resonant ZVS inverter for induction-heated cooker, together with its power regulation characteristics on the basis of its simulation and experimental results. The steady-state performances of this inverter developed for multi-burner type induction-heated food cooking appliance are evaluated and discussed from a practical point of view.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.6
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• pp.48-53
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• 1996

In this paper, the illuminance of elementary, junior, and senior high school in Inchon was measured and analyzed to investigate their night illuminating circumstances(classrooms, science rooms, and laboratories). More than four schools were selected based on the years elapsed(l0, 20, and 30 years, etc) since the opening of the schools. It was shown that the average illuminance for the classroom and that for science room and laboratory have been improved significantly such that the former was 235.6[lx] (260[lx] for senior high school, 208[lx] for junior high school, 203[lx]) for elementary school) and the latter was 233.7[lx](248.8[lx] for senior high school, 216.4[lx] for junior high school, 207.8[lx] for elementary school). The uniformity of the illuminance was exceedingly worse than the recommended one(the average value for the classroom and that for sciense room and laboratory were 0.95 and 1.08, respectively). It was found that the maximum to minimum illuminance ratio with respect to illumination derivative(7.9 for classroom, 6.8 for scienceroom or laboratory) was very high for most school buildings and was much higher for the old ones. From the measured results, it was shown that the illuminance for the school buildings needs to be improved with regard to quality.

• Journal of Microbiology and Biotechnology
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• v.22 no.4
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• pp.479-483
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• 2012

The secretory efficiency of recombinant xylanase xynB from yeast Pichia pastoris between the ${\alpha}$-factor preprosequence and a classical mammalian signal peptide derived from bovine ${\beta}$-casein was compared. The results showed that although the bovine ${\beta}$-casein signal peptide could direct high-level secretion of recombinant xylanase, it was relatively less efficient than the ${\alpha}$-factor preprosequence. In contrast, the bovine ${\beta}$-casein signal peptide caused remarkably more recombinant xylanase trapped intracellularly. Real-time RT-PCR analysis indicated that the difference in the secretory level between the two signal sequences was not due to the difference in the transcriptional efficiency.

• Steel and Composite Structures
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• v.36 no.2
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• pp.187-196
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• 2020

Double skin composite wall system owns several structural merits in terms of high load-carrying capacity, large axial stiffness, and favorable ductility. A recently proposed form of truss connector was used to bond the steel plates to the concrete core to achieve good composite action. The structural behavior of rectangular high walls under compression and T-shaped high walls under eccentric compression has been investigated by the authors. Furthermore, the influences of the truss spacings, the wall width, and the faceplate thickness have been previously studied by the authors on short walls under uniform compression. This paper experimentally investigated the effect of width-to-thickness ratio on the compressive behavior of short walls. Compressive tests were conducted on three short specimens with different width-to-thickness ratios. Based on the test results, it is found that the composite wall shows high compressive resistance and good ductility. The walls fail by local buckling of steel plates and crushing of concrete core. It is also observed that width-to-thickness ratio has great influence on the compressive resistance, initial stiffness, and strain distribution across the section. Finally, the test results are compared with the predictions by modern codes.

• Hwankyungkyoyuk
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• v.18 no.2 s.27
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• pp.101-112
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• 2005

The purpose of this study is to develop environmental inquiry activities for teaching the 10th grade students in science classes of high school. The activities are developed to perform goals of environmental education for sustainable development. In order to this, activities are sequently organized in order of context of laboratory, field, and problem solving in respect of one learning topic. The object of inquiry activities in laboratory context is understanding concepts related environment and environmental pollution. The inquiry activities in field context have an object of attaining good awareness and attitude toward environment. Throughout the activities in probem solving context students are expected to have a mind of participating in environmental issues. The activities are designed to learn and use integrated science knowledge in many domains. Some activities are intended to utilize MBL(Microcomputer-based Laboratory). The ICT materials, lesson plans, instructional sheets for teaching and student' sheets for inquiry were produced to guide these activities. It is expected that this effort will contribute to cultivate environmental literate persons who have not only scientific understanding but also practical will of environmental issues.