• Advances in concrete construction
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• 제14권5호
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• pp.299-307
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• 2022

Cement-based matrixes have low tensile strength and negligible ductility. Adding fibres to these matrixes will improve their mechanical properties and make these composites suitable for structural applications. Post-cracking tensile strength of steel fibers-reinforced cementitious composite materials is directly related to the number of transverse fibers passing through the crack width and the pulling-out behavior of each of the fibers. Therefore, the exact recognition of the pullout behavior of single fibers is necessary to understand the uniaxial tensile and bending behavior of steel fiber-reinforced concrete. In this paper, an experimental study has been carried out on the pullout behavior of 3D (steel fibers with totally two hooks at both ends), 4D (steel fibers with a total of four hooks at both ends), and 5D (steel fibers with totally six hooks at both ends) in which the fibers have been located either perpendicular to the crack width or in an inclined manner. The pullout behavior of the mentioned steel fibers at an inclination angle of 0, 15, 30, 45, and 60 degrees and with embedded lengths of 10, 15, 20, 25, and 30 millimetres is studied in order to explore the simultaneous effect of the inclination angle of the fibers relative to the alongside loading and the embedded length of fibers on the pullout response in each case, including the maximal pullout force, the slip of the maximum point of pullout force, pullout energy, fiber rupture, and concrete matrix spalling. The results showed that the maximum pullout energy in 3D, 4D, and 5D steel fibers with different embedded lengths occurs at 0 to 30° inclination angles. In 5D fibers, maximum pullout energy occurs at a 30° angle with a 25 mm embedded length.

• Earthquakes and Structures
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• 제15권2호
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• pp.123-132
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• 2018

In this paper the strain energy density (SED) model is used to analyze the seismic behavior of suspen-domes and a new criterion is established for judging the seismic failure based on a characteristic point in the SED model. Firstly, a nonlinear time-history response analysis was carried out using the finite-element package ANSYS for typical suspen-domes subjected to different ground motions. The seismic responses including nodal displacements, ratios of yielding members, strain energy density and structural maximum deformation energy were extracted corresponding to the increasing peak ground acceleration (A). Secondly, the SED sum ($I_d$) was calculated which revealed that the $I_d-A$ curve exhibited a relatively large change (called a characteristic point) at a certain value of A with a very small load increment after the structures entered the elastic-plastic state. Thirdly, a SED criterion is proposed to judge the seismic failure load based on the characteristic point. Subsequently, the case study verifies the characteristic point and the proposed SED criterion. Finally, this paper describes the unity and application of the SED criterion. The SED method may open a new way for structural appraisal and the SED criterion might give a unified criterion for predicting the failure loads of various structures subjected to dynamic loads.

• 전자공학회논문지B
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• 제30B권4호
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• pp.1-10
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• 1993

In this paper, a new method of phoneme segmentation of handwritten Korean characters using the local graph pattern is proposed. At first, thinning was performed before extracting features. End-point, inflexion-point, branch-point and cross-point were extracted as features. Using these features and the angular relations between these features, local graph pattern was made. When local graph pattern is made, the of strokes is investigated on contacting point. From this process, pattern is simplified as contacting pattern of the basic form and the contacting form we must take into account can be restricted within fixed region, 4therefore phoneme segmentation not influenced by characters form and any other contact in a single character is performed as matching this local graph pattern with base patterns searched ahead. This experiments with 540 characters have been conducted. From the result of this experiment, it is shown that phoneme segmentation is independent of characters form and other contact in a single character to obtain a correct segmentation rate of 95%, manages it efficiently to reduce the time spent in lock operation when the lock.

• 원예과학기술지
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• 제19권4호
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• pp.579-584
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• 2001

안개초 고품질 절화 생산을 위해 'Bristol Fairy' 삽아묘를 공시하여 토양수분 포텐셜을 영양생장기에는 -3.2, -10.0kPa, 출뢰기 이후에는 -10.0, -31.6, -79.4kPa로 설정하고 토양수분이 관수 개시점에 도달했을 때 10mm씩 관수하여 봄, 가을 연속재배를 하였다. 개화는 영양생장기, 출뢰기 이후 토양수분 포텐셜이 낮을수록 빨라지는 경향이었으며, 그 외 개화기 생육에는 처리 간 차이가 없었다. 봄, 가을 재배 모두 토양수분 포텐셜이 낮을수록 측지장은 짧아지고 화경의 강도는 강해지며, 상위 절간장도 짧아 휘어진 정도가 감소하였다. 특히, 가을 재배 시 토양수분 포텐셜이 높을수록 측지장이 정단보다 높아 원추화서가 파괴되는 경향이 심하였다. 봄 절화의 절화량은 처리 간 유의한 차이가 없었지만, 가을은 토양수분 포텐셜이 낮을수록 증가하였다. 따라서 안개초 고품질 절화 생산을 위한 관수개시점은 영양생장기는 -10.0kPa, 출뢰기 후에는 -79.4kPa이 적정하다고 생각되었다.

• 한국전자파학회논문지
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• 제16권6호
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• pp.622-631
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• 2005

본 논문에서는 전자파 방사 내성 시험의 불확실성 요인이 되는 '오버 및 언더 편차'와 그로 인해 발생하는 '오버 및 언더 테스팅'을 줄이고자 기존 균일장 측정 방법의 문제점을 비교 분석하고 '오버 및 언더 편차'를 최소화할 수 있는 새로운 균일장 측정 방법을 제안하였다. 성능이 다른 4개의 국내 시험 기관 무반사실에 이를 적용하여 기존 측정 방법과 비교 실험하였으며 6 dB을 초과하는 필드에 대해 최소 편차인 FDI(Field Deviation Index)와 비교 분석하였다. 실험에 대한 분석 결과 '오버 및 언더 편차'는 제안 방법이 FDI와 동일하게 나타났으며 특정 주파수에선 현재 국내 규격 및 국제 규격보다 4.9 dB, 2.37 dB 개선되었고 전체 주파수에서는 평균적으로 1.193 dB, 0.017 dB 개선되었다. '오버 및 언더 테스팅 포인트'는 제안 방법이 기존 방법보다 최대 926개, 10개 포인트가 적게 측정되었으며 균일 영역 중심부 4포인트에서는 최대 118개, 9개 적게 측정되었으며, 다른 포인트에 대한 비율 또한 가장 낮게 측정되어 시험의 불확실성의 요인을 최소화하였음을 확인하였다.

• Safety and Health at Work
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• 제4권1호
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• pp.52-62
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• 2013

Objectives: To investigate the association between psychological distress and obesity among law enforcement officers (LEOs) in the United States. Methods: Self-reported data on psychological distress based on six key questions were obtained from LEOs who participated in the National Health Interview Survey (2004-2010). We used Prochaska's cut-point of a Kessler 6 score ${\geq}5$ for moderate/high mental distress in our analysis. Mean levels of body mass index (BMI) were compared across three levels of psychological distress. Results: The average age of LEOs (n = 929) was 39.3 years; 25% were female. Overall, 8.1% of LEOs had moderate or high psychological distress; 37.5% were obese (BMI ${\geq}30$). Mean BMI increased with increasing psychological distress (no distress, BMI = $27.2kg/m^2$; mild distress, $27.6kg/m^2$; and moderate/high distress, $33.1kg/m^2$; p = 0.016) after adjustment for age, race, income, and education level among female officers only. Physical activity modified the association between psychological distress and BMI but only among male LEOs (interaction p = 0.002). Among male LEOs reporting low physical activity, psychological distress was positively associated with BMI ($30.3kg/m^2$ for no distress, 30.7 for mild distress, 31.8 for moderate/high distress; p = 0.179) after adjustment, but not significantly. This association was not significant among males reporting high physical activity. Conclusion: Mean BMI significantly increased as psychological distress increased among female LEOs. A longitudinal study design may reveal the directionality of this association as well as the potential role that physical activity might play in this association.

• 환경영향평가
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• 제16권2호
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• pp.143-156
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• 2007

This study has researched the management status and the pollution level of water, soil, stream sediments of 11 abandoned coal mines out of a total of 12 within Obong-Dam area except Bukyung mine, which was submerged when constructing Obong-Dam, and selected areas which are in needs to have pollution control facilities in the first place. From the results of examination on the runoff at the waste rock pile and mineheads, the runoff from Sueun mine (pH, Fe, Al), Samwon mine (pH, Al), Wangdo mine (pH, Al), Mose mine (pH, Fe, Al) and Daeryeong mine (pH) exceeded the permissible discharge standards of the water quality, but the water at merging point with Obong-Dam after joined with Doma branch satisfied both Water Quality Standards and Drinking Water Quality Standards. In regard to groundwater contamination, it is found that areas where exceeded the Drinking Water Quality Standards are Wangdo mine (pH), Jangjae mine (pH, Zn), Daeryeong mine (pH) whereas all areas satisfied Soil Contamination Warning Standards of Soil Environmental Conservation Law. When comparing a research result on underwater sediments of branches of abandoned mines to the EPA Guidelines for classification of great lakes harbor sediments, Dongguk Gaerim (Fe), Jungwon mine (Fe), Daebo mine (Mn), Samwon mine (Mn) and Daeryeong mine (Mn) showed mid-level of contamination, whereas Sueun (Fe, Mn), Daebo mine (Fe), Woosung mine (Fe, Mn), Wangdo mine (Fe, Mn), Mose mine (Fe) and Daeryeong mine (Fe) showed high-level of contamination. In addition, contamination levels of underwater sediments in Wangsan and Doma branch where abandoned mine's branches merge together, Wangsan branch showed no contamination at all whereas Doma branch shows mid-level of contamination which reflect the Doma branch is affected by waste rock pile and minehead runoff of the abandoned mines in the Doma branch area. It is concluded that Mose mine and Sueun mine required treatment of acid mine drainage. and Wangdo, Jungwon, and Samwon mines were in need of mine tailing and erosion control work. The Samwon mine additionally required a control system for closed minehead runoff. Although the Samwon mine reached a high concentration of Al, Mn $Ca^{2+}$, $SO{_4}^{2-}$ in the runoff, the levels decreased after it was combined with a tributary. It has been concluded that after further monitoring of the cause of pollution, a preventive measure system may be needed to be built.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.246-249
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• 2000

In this paper, we describe an automated extraction program that transforms a mask layout into an approximated equivalent circuit information suitable for circuit simulation, and that extract the geometric parameters of stacked MOSFETs and the distributed RCs of layout blocks. To extract equivalent circuit from mask layout, we propose new block disassembly technique capable of accurate computations of distributed RCs at branch point, using vectorized edges which represent the outline of an individual polygon.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.325-329
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• 2000

An effective Carrier-Based PWM scheme that enables the instantaneous quality of each branch point voltage of a diode clamped 4-level inverter to be reduced at a low modulation index is described. This scheme presents a computed zero sequence voltage of PWM by the feedback of both DC-link voltages and load currents. The proposed PWM scheme enables to increase the controllable region of DC-link voltage and makes it possible to operate with small DC-link capacitors. The validity of the proposed PWM scheme is verified by simulation results.

• 대한수학회논문집
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• 제31권4호
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• pp.729-743
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• 2016

In the current work, the intuitionistic fuzzy version of Hyers-Ulam stability for a nonic functional equation by applying a fixed point method is investigated. This way shows that some fixed points of a suitable operator can be a nonic mapping.