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Earthquake performance of FRP retrofitting of short columns around band-type windows

  • Kocak, Ali
    • Structural Engineering and Mechanics
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    • v.53 no.1
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    • pp.1-16
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    • 2015
  • Due to design codes and regulations and the variety of building plans in Turkey, it is very often seen that band-type windows are left for ventilation and lightening of the basements of buildings which are used for various purposes such as workplaces and storage. Therefore when the necessary support measures cannot be given, short columns are subjected to very high shear forces and so damage occurs. One of the precautions to avoid the damage of short column mechanisms in buildings where band-type windows are in the basement is to strengthen the short columns with fiber reinforced polymer (FRP). In this study, the effect of the FRP retrofitting process of the short columns around band-windowed structures, which are found especially in basement areas, is analyzed in accordance with Turkish Seismic Code 2007 (TSC 2007). Three different models which are bare frame, frame with short columns and retrofitted short columns with FRP, are created and analyzed according to TSC 2007 performance analysis methods to understand the effects of band windows in basements and the effect of FRP retrofitting.

24 hour Load Forecasting using Combined Very-short-term and Short-term Multi-Variable Time-Series Model (초단기 및 단기 다변수 시계열 결합모델을 이용한 24시간 부하예측)

  • Lee, WonJun;Lee, Munsu;Kang, Byung-O;Jung, Jaesung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.3
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    • pp.493-499
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    • 2017
  • This paper proposes a combined very-short-term and short-term multi-variate time-series model for 24 hour load forecasting. First, the best model for very-short-term and short-term load forecasting is selected by considering the least error value, and then they are combined by the optimal forecasting time. The actual load data of industry complex is used to show the effectiveness of the proposed model. As a result the load forecasting accuracy of the combined model has increased more than a single model for 24 hour load forecasting.

Research on the Short-term Memory Effects on VR Tour Games

  • Sui, Qiao;Cho, Dong-Min
    • Journal of Korea Multimedia Society
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    • v.24 no.7
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    • pp.922-932
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    • 2021
  • This thesis mainly studies the impact of short-term memory in VR tour games on users. The thesis is based on VR tour games and short-term memory, using the literature research method, the practical research method, and the investigation method. First, the author designs and makes VR tour games on the Beijing-Hangzhou Grand Canal, and then conducts a questionnaire survey and designs a control experiment. The experiment explores the differences of the short-term memory level of individuals between the normal environment and the VR tour game environment. It verifies whether the influential hypothesis proposed by the research is correct. Research conclusions show that: VR tour games have an impact on short-term memory. Compared with the normal environment, the subjects have better performance in the VR tour game mode and can maintain a high short-term memory level for a longer time. Its conclusions should promote the cultural propaganda of scenic spots and provide theoretical support for tourists' short-term memory of scenic spots culture.

Proposal for a virtual museum with vertical aspect ratio for the convergence of metaverse and short-form content

  • Il-hyun Cho
    • International journal of advanced smart convergence
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    • v.12 no.3
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    • pp.119-126
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    • 2023
  • This study explores the convergence of metaverse and short-form content, proposing a new approach for viewing short-form content with a vertical aspect ratio on a metaverse platform and within a virtual museum. Short-form content has gained popularity due to the snack culture and is proving to be advantageous in e-commerce. By studying the relationship between vertical ratio screens and gaze, we confirm the effectiveness of vertical ratio short-form content in providing immersive experiences and fostering sharing and communication. The proposed virtual museum offers opportunities for innovative businesses to market through fandom. This research highlights the value of vertical proportion short-form content and its significance in the convergence of metaverse and short-form content. It aims to contribute to industry development, provide new creative directions, enhance personal visual experiences, and expand applicability in related fields.

Short-circuit Protection Circuit Design for SiC MOSFET Using Current Sensing Circuit Based on Rogowski Coil (Rogowski Coil 기반의 전류 센싱 회로를 적용한 SiC MOSFET 단락 보호 회로 설계)

  • Lee, Ju-A;Byun, Jongeun;Ann, Sangjoon;Son, Won-Jin;Lee, Byoung-Kuk
    • The Transactions of the Korean Institute of Power Electronics
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    • v.26 no.3
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    • pp.214-221
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    • 2021
  • SiC MOSFETs require a faster and more reliable short-circuit protection circuit than conventional methods due to narrow short-circuit withstand times. Therefore, this research proposes a short-circuit protection circuit using a current-sensing circuit based on Rogowski coil. The method of designing the current-sensing circuit, which is a component of the proposed circuit, is presented first. The integrator and input/output filter that compose the current-sensing circuit are designed to have a wide bandwidth for accurately measuring short-circuit currents with high di/dt. The precision of the designed sensing circuit is verified on a double pulse test (DPT). In addition, the sensing accuracy according to the bandwidth of the filters and the number of turns of the Rogowski coil is analyzed. Next, the entire short-circuit protection circuit with the current-sensing circuit is designed in consideration of the fast short-circuit shutdown time. To verify the performance of this circuit, a short-circuit test is conducted for two cases of short-circuit conditions that can occur in the half-bridge structure. Finally, the short-circuit shutdown time is measured to confirm the suitability of the proposed protection circuit for the SiC MOSFET short-circuit protection.

A New Ac-to-Dc Power Converter for a Load with Frequent Short Circuits (부하단락이 빈번히 발생하는 경우에 적합한 교류-직류 전력변환기)

  • No, Ui-Cheol;Kim, In-Dong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.7
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    • pp.384-390
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    • 1999
  • This paper describes a new ac-to-dc power converter using a multilevel converter. A conventional multilevel ac-to-dc converter has large output dc filter capacitors. When a short circuit happens in a load, the stored energy in the capacitors should be discharged through the load with a high short circuit current. The high current may cause considerable damage to the capacitors and the load. The output dc capacitors of the proposed converter do not discharge even under load short circuit condition. In the case of a load short circuit, the capacitors become a floating state immediately and remain in the state. Then the stored capacitor energy is supplied to the load again as soon as the short circuit has been cleared. Therefore, the rising time of the load voltage can be significantly reduced. This feature satisfies the requirement of a power supply for a load with frequent short circuits. The proposed converter has the characteristics of a simplified structure, a reduced cost, weight, and volume compared with conventional power supplies with frequent output short circuits. Experimental results are presented to verify the usefulness of the proposed converter.

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Experimental research on seismic behavior of steel reinforced high-strength concrete short columns

  • Zhu, Weiqing;Jia, Jinqing;Zhang, Junguang
    • Steel and Composite Structures
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    • v.25 no.5
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    • pp.603-615
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    • 2017
  • This experimental research presents the seismic performance of steel reinforced high-strength concrete (SRHC) short columns. Eleven SRHC column specimens were tested under simulated earthquake loading conditions, including six short column specimens and five normal column specimens. The parameters studied included the axial load level, stirrup details and shear span ratio. The failure modes, critical region length, energy dissipation capacity and deformation capacity, stiffness and strength degradation and shear displacement of SRHC short columns were analyzed in detail. The effects of the parameters on seismic performance were discussed. The test results showed that SRHC short columns exhibited shear-flexure failure characteristics. The critical region length of SRHC short columns could be taken as the whole column height, regardless of axial load level. In comparison to SRHC normal columns, SRHC short columns had weaker energy dissipation capacity and deformation capacity, and experienced faster stiffness degradation and strength degradation. The decrease in energy dissipation and deformation capacity due to the decreasing shear span ratio was more serious when the axial load level was higher. However, SRHC short columns confined by multiple stirrups might possess good seismic behavior with enough deformation capacity (ultimate drift ratio ${\geq}2.5%$), even though a relative large axial load ratio (= 0.38) and relative small structural steel ratio (= 3.58%) were used, and were suitable to be used in tall buildings in earthquake regions.

Crack Closure and Growth Behavior of Short Fatigue Cracks under Random Loading (Part II : Growth Behavior and Growth Life Prediction) (짧은 피로균열의 랜덤하중하의 균열닫힘 및 진전거동(Part II : 진전거동 및 진전수명예측))

  • Lee, Shin-Young;Song, Ji-Ho
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.141-146
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    • 2000
  • Crack closure and growth behavior of physically short fatigue cracks under random loading are investigated by performing narrow- and wide-band random loading tests for various stress ratios. The importance of the crack closure phenomenon is examined by predicting the growth lives of short cracks using obtained crack opening behavior. Artificially prepared two-dimensional, short through-thickness cracks are used. The crack opening load of short cracks is much lower under random loading than under constant-amplitude loading corresponding to the largest load cycle in a random load history. This result indicates that the largest load cycle in a random load history has an effect to enhance crack opening of short cracks. Most of the life prediction ratios are within the factor of 2 scatter band except several data at very short crack sizes, indicating that crack growth predictions based on the measured crack opening data are excellent. From the results obtained in this study, it can be concluded that crack closure is the primary factor governing fatigue crack growth of short cracks under random loading as well as under constant-amplitude loading.

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Evaluation of craniofacial morphology in short-statured children: growth hormone deficiency versus idiopathic short stature

  • Kim, Ki Bong;Kim, Eun-Kyong;Jang, Kyung Mi;Kim, Min Seon;Park, Eun Young
    • Journal of Yeungnam Medical Science
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    • v.38 no.1
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    • pp.47-52
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    • 2021
  • Background: Short stature is defined as a height below the 3rd percentile or more than two standard deviations below the mean for a given age, sex, and population. There have been inconsistent results regarding craniofacial morphology in short-statured children. This study aimed to analyze the differences between short-statured children with growth hormone deficiency, idiopathic short-statured children, and normal children. Methods: Thirty-one short-statured children with growth hormone deficiency, 32 idiopathic short-statured children, and 32 healthy children were enrolled in this study. The measurements of their craniofacial structures from lateral cephalograms were evaluated. Results: There were statistically significant differences among the three groups seven variables (anterior cranial base length, posterior cranial base length, total cranial base length, upper posterior facial height, posterior total facial height, mandibular ramus length, and overall mandibular length) in the linear measurement and five variables (saddle angle, gonial angle, mandibular plane angle, position of mandible, and maxilla versus mandible) in the angular measurement. Conclusion: Compared to the control group, many linear and angular measurements of the craniofacial structures were significantly different in the two short-statured groups (p <0.05). Treatment plans by orthodontists should include these craniofacial structure characteristics.

Body Characteristics, Perceived Body Size and Body-Cathexis for Short Women Aged 18 to 59 (18~59세 키 작은 여성의 체형특징, 신체인식과 신체만족도 분석)

  • Lee, Jeong-Yim
    • Journal of the Korean Society of Clothing and Textiles
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    • v.35 no.11
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    • pp.1346-1361
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    • 2011
  • This study examined the body characteristics, perceived body size and body-cathexis according to the stature of women aged 18 to 59. Special focus was on women of short stature; in addition, the study searched for the proper clothing fit and satisfaction level for short women. The 2010 SizeKorea data of 2,586 women aged 18 to 59 was analyzed statistically to find the distribution of stature according to 4 age groups along with the body characteristics and proportion of 3 stature groups in each age group. A questionnaire was conducted with responses from 412 women aged 18 to 59, and the perceived body size and satisfaction with body size of 3 stature groups were studied with 5 Likert scales. Although the stature of Korean women has increased, short stature women (those under 155cm) still represent a high percentage of individuals in Korea. Short women (small in height and length) had unique body characteristics in width, depth, and girth that were distinguished from the characteristics of medium or tall women. Especially, the lower body part of short women had distinct characteristics. Accordingly, it is undesirable to reflect the same ease or same body proportion in clothing construction for the 3 stature groups. Short women perceived their stature and length of upper or lower body as too short and the satisfaction with their body size was lower than medium or tall women. To upgrade the clothing fit and satisfaction of short women, it is necessary to reflect the unique body characteristics of short women in clothing design and construction.