• Structural Engineering and Mechanics
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• 제64권1호
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• pp.11-21
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• 2017

It has been observed in the past that, the reinforced concrete (RC) bridge columns are very often subjected to torsional moment in addition to flexure and shear during seismic vibration. Ignoring torsion in the design can trigger unexpected shear failure of the columns (Farhey et al. 1993). Performance based seismic design is a popular design philosophy which calls for accurate prediction of the hysteresis behavior of structural elements to ensure safe and economical design under earthquake loading. However, very few investigations in the past focused on the development of analytical models to accurately predict the response of RC members under cyclic torsion. Previously developed hysteresis models are not readily applicable for torsional loading owing to significant pinching and stiffness degradation associated with torsion (Wang et al. 2014). The present study proposes an improved polygonal hysteresis model which can accurately predict the hysteretic behavior of RC circular and square columns under torsion. The primary curve is obtained from mechanics based softened truss model for torsion. The proposed model is validated with test data of two circular and two square columns. A good correlation is observed between the predicted and measured torque-twist behavior and dissipated energy.

• 전산구조공학
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• 제10권3호
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• pp.225-231
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• 1997

제어봉 구동장치(CEDM)의 동적거동은 원자로의 동적거동과 연동되어 있어, 두 구조물 간의 상호 동적 특성을 이해한 후 CEDM의 설계 개선 방향을 정립해야 한다. 원자로와 CEDM을 각각 1차 질량 및 2차 질량으로 하는 2 자유도계로 단순화하여 상호 동적 영향을 검토하고, 두 질량의 응답을 모두 감소시키는 최적의 .mu.-f곡선을 제시하였다. 설계 개선은 고유진동수비 f를 가능한 0.93부근으로 수렴시켜야 하며, 질량비 .mu.는 감소시키지 않아야 하고, 제시된 최적의 .mu.-f곡선에 접근시키는 방향으로 해야 함을 제안하였다. 이에 따라 CEDM의 부품들의 설계를 최적화하여 원자로와 CEDM의 변위 응답비를 각각 10.5-19.7%와 6.3-3.4%씩 모두 감소시킬 수 있었다.

• 한국농공학회지
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• 제18권4호
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• pp.4242-4250
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• 1976

The determination of the pre-consolidation load known to have a great effect on the consolidation characteristics of the soil have been researched and discussed in detail by many other researchers. A study was undertaken to investigate and compare the effect of pre-consolidation loads on the coefficient of permeability and the consolidation characterisics of soil through the consolidation test on the three types of soil samples. The results of this study are follows; 1. Large compression index is dependent on initial void ratio of the sample being used and the pressure-void ratio curve shows a curved linear relationship in over-consolidated area but a linear relationship in normally consolidated area.2. Settlement-time curve is S-shaped where the pressure is larger than pre-consolidation load and regardless of over-burden pressure, it is a similar straight line respectively in the secondary consolidation area. 3. Primary consolidation ratio of the sample increases almost linearly with the increase of over-burden pressure but the coefficient of volume compressibility decreases linearly with the increase of it. 4. Time factor of a certain degree of consolidation increases with over-burden pressure but the coefficient of consolidation decreases with it in over-consolidated area. There is a linear relationship between them in normally consolidated area. 5. The void ratio of completion point of primary consolidation decreases linearly with over-burden pressure. 6. The coefficient of permeability of sample decreases linearly with over-burden pressure in normally consolidated area, also it increases linearly with increment of the void ratio of the sample.

• 한국정보전자통신기술학회논문지
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• 제5권4호
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• pp.211-215
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• 2012

대형의료기기는 환자 진단과 치료 행위에 있어서 매우 중요한 기기이다. 이런 대형의료기기를 사용하여 환자를 진단 또는 치료할 때 의료기기의 회로 내에서 갑작스런 전류의 변화는 회로의 단락 등 매우 심각한 문제를 일으킨다. 특히 회로 내에서 전류변환기에 큰 부하가 걸리게 한다. 이것으로 인해 변환기는 포화에 이르게 되는데 이것은 철심코일 인턱터의 magnetic curve에 기인한다. 이와 같이 변환기가 saturate에 이르게 되면 1차 측과 2차 측의 변환 비율이 깨지게 되고 회로가 단락되는 문제가 발생하게 된다. 이 논문 에서는 대형의료기기에 사용되는 current 변환기의 입력 측에 갑작스런 큰 전류 변화가 발생 했을 때 일어나는 그에 따른 포화 상태와 그의 2차 측 전류의 변화를 simulation 해본다.

• Journal of Preventive Medicine and Public Health
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• 제11권1호
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• pp.31-40
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• 1978

저자는 1970년부터 1975년까지 6 년갑에 걸쳐 부산지역 국민학교 학생들의 신체발육상태를 평가하고져 무작위로 추출한 부산시 모 국민학교 학생 656명(남 374, 여 282)을 대상으로 그들의 실제 신체체격 측정을 통하여 과거 6 년 동안의 신체발육상태를 조사 분석하여 다음의 결론을 얻었다. (1) 신장의 연간 최대성장연령은 남자$7{\sim}8$세 (5.9cm), 여자 $10{\sim}11$세 (6.5cm)이었고 남녀 신장발육곡선은 $10{\sim}11$세에서 서로 교차하였다. (2) 체중의 연간 최대성장연령은 남자 $9{\sim}10$세(3.1kg), 여자 $10{\sim}11$세 (3.9kg)이었고 남녀체중발육 곡선은 $10{\sim}11$세에서 서로 교차하였다. (3) 흉위의 연간 최대성장연령은 남자 $8{\sim}9$세(3.1cm), 여자 $9{\sim}10$세 (2.9cm)이었고 전자와는 달리 남녀 융위발육곡선은 서로 교차하지 않았다. 4. 좌고의 연간 최대성장연령은 남녀 모두 $6{\sim}7$세 (남 3.3cm, 여 3.4cm)이었고 남너 좌고발육곡선은 $8{\sim}9$세에서 서로 교차하였다. (5) 각 지역간의 비교에는 각각의 신체계측치를 체격종합치 (Physical Integrated Ualue)로서 서로 비교하는 것이 매우 간편하고 바람직 하였으며 한국소아 신체표준발육치에 대한 부산지역 국민학교 학동들의 체격종합치 (Physical Integrated Value)는 남여 각각 신장 +0.30, +0.29, 체중 +0.33, +0.35 흉위 +0.65, +0.57, 좌고 +0.10, +0.20으로 서울을 제외한 타지역 (대구, 대전, 농촌지역)에 비하여 비교적 우수하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.194-196
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• 2000

This paper presents a new digital relaying algorithm for protection of a two winding power transformer. The proposed algorithm calculates mutual flux linkages of primary and secondary windings from the currents and voltages of primary and secondary windings. The mutual flux linkage ratio of primary and secondary windings is equal to the turn ratio in case of the steady state and magnetic inrush. On the other hand, the ratio is different from the turn ratio in case of internal winding faults. The algorithm does not require B-H curve. The results of various tests are satisfactory.

• 대한전기학회논문지:전력기술부문A
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• 제49권10호
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• pp.524-530
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• 2000

This paper presents a transformer protective relaying algorithm using the ratio of induced voltages. The proposed algorithm calculates primary and secondary voltage from currents and voltages of primary and secondary windings. The ratio of primary and secondary induced voltages is equal to the turn ratio in case of the steady state and magnetic inrush. On the other hand, the ratio is different form the turn ratio in case of internal winding faults. The algorithm does not require B-H curve and can reduce the relay's operating time.

• 한국인쇄학회:학술대회논문집
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• 한국인쇄학회 2000년도 춘계 학술발표회 논문집
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• pp.25-34
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• 2000

Recently, color proofing in printing industry grow rapidly. If an order decide color from known color information in the case of color reproduction, we can reduce expenses and time. In color proofing the best important point must be closed proofed color to primary color and secondary color. Model-based approaches have the advantages of faster recharacterization and the opportunity of simulating product enhancements such as changes in ink properties and halftoning. In this paper, we transformed the dot area of CMYK to CIELAB color space using color reprodution models. Firstly, we measured spectral reflectance of primary color printed by Matchprint II and the data was used to find tone reproduction curve using regression equation, and than we applied at primary color model, such as Murray-Davies, Yule-Nilsen, and mixed color model, such as Kubelka--Munk, relaxed version of spectral Neugebauser. In such results, the Kubleka-Munk model resulted in the best spectral reconstruction accuracy followed by relaxed version of spectral Neugebauer model, color difference is 2.8401.

• 한국인쇄학회지
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• 제18권2호
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• pp.29-40
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• 2000

Recently. color proofing in printing industry grow rapidly. If an order decide color from known color information in the case of color reproduction, we can reduce expenses and time. In color proofing the best important point must be closed proofed color to primary color and secondary color. Model-based approaches have the advantages of faster recharacterization and the opportunity of simulating product enhancements such as changes in ink properties and halftoning. In this paper, we transformed the dot area of CMYK to CIELAB color space using color reproduction models. Firstly, we measured spectral reflectance of primary color printed by Matchprint II and the data was used to find tone reproduction curve using regression equation, and than we applied at primary color model, such as Murray-Davies, Yule-Nilsen, and mixed color model, such as Kubelka-Munk, relaxed version of spectral Neugebauer. In such results, the Kubelka-Munk model resulted in the best spectral reconstruction accuracy followed by relaxed version of spectral Neugebauer model, color difference is 2.8401.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.65-66
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• 2008

This paper proposes a compensating algorithm for the secondary current of the measurement current transformer (CT) that removes the effects of the hysteresis characteristics of the iron-core. The exciting current resulting from the hysteresis characteristics of the core causes an error between the primary current and the secondary current of the CT. The proposed algorithm decomposes the exciting current into the magnetizing current and the core loss current and each of them is estimated. The core loss current is calculated from the secondary voltage and the secondary voltage-core loss current curve. The core flux linkage is calculated and then inserted into the flux-current curve to estimate the magnetizing current. The exciting current at every sampling interval is obtained by summing the core-loss and magnetizing currents and then added to the measured current to compensate the secondary current. The performance of the proposed algorithm is validated under various conditions using EMTP generated data. The test results of the real CT were also included. The results indicate that the proposed algorithm can improve the accuracy of the measurement CT significantly, and thus reduce the size and the cost of the CT.