• 한국정밀공학회지
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• 제28권1호
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• pp.63-72
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• 2011

In recent years, hot-stamped components are more increasingly used in the automotive industry in order to reduce weight and to improve the strength of vehicles. In hot stamping process, blank is hot formed and press hardened in a tool. However, in hot stamping without cooling channel, temperature of the tool increases gradually in mass production thus cannot meet the critical cooling rate to obtain high strength over 1500MPa. Warpage occurs in the hot stamped component due to non-uniform stress state caused by unbalanced cooling. Therefore, tools should be uniformly as well as rapidly cooled down by the coolant which flows through cooling channel. In this paper, optimal design method of cooling channel to obtain uniform and high strength of the component is proposed. Optimized cooling channel is applied to the hot press V-bending process. As a result of measuring strength, hardness and microstructure of the hot formed parts, it is known that the design methodology of cooling channel is effective to the hot stamping process.

• KEPCO Journal on Electric Power and Energy
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• 제2권4호
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• pp.609-613
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• 2016

전기자동차 배터리 셀들 간의 불균형 충전 문제를 해결하기 위해, 직병렬 하이브리드 충전 구조를 개발하였다. 이 방법은 직렬 부분에 의해 주 충전이 수행되며 병렬 부분에 의해 밸런싱이 수행되는데, 이 때, 직렬 부분은 부피가 크고 무겁지만 병렬 부분은 직렬 부분보다 작고 가볍다. 개별 배터리 셀 전압을 측정하기 위한 센서 어레이, 듀티비 제어를 포함한 IGBT, 그리고 배터리 관리 시스템은 제안된 시스템의 핵심 요소이다.

• 한국통신학회논문지
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• 제31권9C호
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• pp.831-839
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• 2006

본 논문에서는 수신기에서 I/Q 위상 및 진폭 불균형을 갖는 계층적 MPSK(Hierarchical M-ary Phase Shift Keying) 신호에 대해 수치 적분이 필요 없는 정확하고 일반화된 closed-form 형태의 비트 오류 확률(Bit Error Probability) 표현을 유도한다. 새롭게 유도된 비트 오류 확률 표현은 간결한 형태의 일반화된 식으로 되어 있어 다양한 환경으로의 적용이 용이하다. 뿐만 아니라, 계층적 MPSK를 적용하는 많은 디지털 통신 시스템에서 복조시 발생할 수 있는 I/Q 불균형들에 의한 시스템 성능 변화에 대하여 정확한 이론적 성능 기준을 제공할 것으로 기대된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.397_398
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• 2009

Demonstrations to deploy high temperature superconducting (HTS) cable to the real gird are actively carried out throughout the world. Power utilities have an interest in the inherent advantage of the HTS cable system, and achieve the expected results from the series of verification test. To embody the reliability in the phenomenon occurred commonly in three-phase system, we simulate the load unbalance. A 22.9 kV large scale HTS cable system with the specification of 100 m-long, 50 MVA capacity has been tested with up to 30% unbalance rate. To evaluate the effect of AC loss increase due to the unbalanced load, the cooling loads are measured by the calorimetry method. In this paper, the correlation between AC loss and load unbalance is described and investigated precisely.

• Journal of Chest Surgery
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• 제28권8호
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• pp.759-765
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• 1995

We reviewed our experiences on 33 patients who underwent a bidirectional cavopulmonary shunt[BCPS from February 1992 to July 1994. There were 19 male an 14 female patients, and their weight ranged from 4.4 to 13.3 Kg[mean weight 8.4 $\pm$2.9 Kg . The age ranged from 2 to 55 months [mean age 16.7 $\pm$15.5 months . Their diagnosis included single ventricle group in 16, unbalanced ventricles in 8 whose associated anomalies were double outlet right ventricle, transposition of great arteries and total anomalous pulmonary venous return, tricuspid atresia in 7, hypoplastic left heart syndrome in 1 who underwent a Norwood procedure and double outlet right ventricle with pulmonic stenosis and tricuspid stenosis in 1 who underwent biventricular repair. Among them 10 patients had received other palliative operation before [Norwood procedure 1, pulmonary artery banding 3, modified Blalock-Taussig shunt 6 . The BCPS operations were performed under the cardiopulmonary bypass. 16 patients underwent unilateral BCPS and 17 patients who had bilateral SVC underwent bilateral BCPS. Three patients whose associated anomalies were interruption of IVC underwent total cavopulmonary shunt. There were 5 operative deaths [mortality rate 15.1 % and 2 late deaths. The risk factor for the operation was high mean pulmonary artery pressure [p value<0.05 . The survivors showed good postoperative course and their postoperative oxygen saturation was increased significantly compared to that of preoperative status[p value<0.05 .Conclusively, BCPS operation is effective and safe palliative procedure for the many cyanotic complex congenital anomalies with decreased pulmonary blood flow especialy for the patients who have the high risk factors for Fontan operations.

• 동아시아식생활학회지
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• 제19권6호
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• pp.846-855
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• 2009

This study was performed to assess gender differences in rates of obesity, dietary behaviors, and nutrient intakes among college students living in Gwangju. Anthropometric measurements showed that the body mass indexes (BMIs) of the males and females were $22.1{\pm}2.6$ and $20.1{\pm}2.4$ respectively. All obesity indices including BMI, relative body weight (RBW), % body fat by bioelectrical impedence analysis (BIA), and waist-hip ratio (WHR) were significantly higher in the males than in the females. Abdominal fat was also found to be higher in the males whereas underweight was prominent in the female students. The dietary behaviors of the males as determined by dietary scores, were poorer than those of the females. Twenty-four hour dietary recalls revealed that most nutrient intakes were adequate, exceptions of vitamin C, Ca, and folate intakes in both sexes and Fe intake in the female students. Ca and folate intakes were below 75% of the KDRI for both genders. In addition, Unbalanced energy ratios of carbohydrate, protein, and fat were noted in both genders. Effective nutrition education programs targeting college students should be developed and implemented to increase Ca and folate consumption. It is suggested that gender-based nutrition education approaches be created due to poor dietary behavior in males and inadequate nutrient intakes in female college students.

• Asian Journal of Business Environment
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• 제3권2호
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• pp.17-22
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• 2013

Purpose - This dissertation is based on previous research, and analyzes processing trade, which constitutes a major section of foreign trade in Shandong Province. Research design, data, and methodology - The study uses the survey data on polarization, which is a vital index reflecting the unbalanced growth of regional economic development. The article introduces the processing trade polarization index, and the processing trade polarization fluctuation rate, to predict the geographical polarization posture and development trends in Shandong Province. Results -The development of processing trade in Shandong Province shows the level of gradient from east to west. The first-line growth pole has been formed and developed, and the initial formation of the diffusion mechanism has taken place. However, coordination problems in accompanying regional development have become increasingly prominent. Conclusions - This study focuses on the development of processing trade strategy and suggests overall coordination of development objectives, using non-balanced development goals. According to regional characteristics and development objectives of the processing trade in Shandong Province, the region around the city is divided into innovation diffusion region, enhanced growth areas, areas expected to undertake development, and areas to upgrade in four levels, given the different policy proposals.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.663-665
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• 2000

We fabricated resistive superconducting fault current limiters (SFCL) based on YBCO thin films grown on 2-inch diameter saphire substrates Two SFCLs with nearly identical properties were connected in series to investigate the simultaneous quench. There was a slight difference in the rate of voltage increase between two SFCL units when they were operated independently. This difference. however, resulted in significantly unbalanced power dissipation between the units. This imbalance was removed by connecting a shunt resistor to an SFCL in parallel. The appropriate values of the shunt resistances were $80{\Omega}$ at $75 V_{rms}$. $100{\Omega}$ at $100 V_{rms}$ and $110{\Omega}$ at $120 V_{rms}$, respectively. Increased power input at high voltages also reduced the initial imbalance in power dissipation. but with increase in film temperature to higher than 200 K.

• Journal of Information Processing Systems
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• 제8권4호
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• pp.555-566
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• 2012

The cloud environment makes it possible to analyze large data sets in a scalable computing infrastructure. In the bioinformatics field, the applications are composed of the complex workflow tasks, which require huge data storage as well as a computing-intensive parallel workload. Many approaches have been introduced in distributed solutions. However, they focus on static resource provisioning with a batch-processing scheme in a local computing farm and data storage. In the case of a large-scale workflow system, it is inevitable and valuable to outsource the entire or a part of their tasks to public clouds for reducing resource costs. The problems, however, occurred at the transfer time for huge dataset as well as there being an unbalanced completion time of different problem sizes. In this paper, we propose an adaptive resource-provisioning scheme that includes run-time data distribution and collection services for hiding the data transfer time. The proposed adaptive resource-provisioning scheme optimizes the allocation ratio of computing elements to the different datasets in order to minimize the total makespan under resource constraints. We conducted the experiments with a well-known sequence alignment algorithm and the results showed that the proposed scheme is efficient for the cloud environment.

• The Journal of Asian Finance, Economics and Business
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• 제8권7호
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• pp.195-201
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• 2021

This study aims to assess the impact of ownership structure of commercial banks on bank credit risk in Vietnam. The authors used the unbalanced table data of 28 commercial banks in the period from 2004 to 2020 with 439 observations. The ratio of loan loss provisioning to loans (CR) is selected as a dependent variable representing credit risk at commercial banks. The regression methods used include: least squares method (OLS), fixed-effect model (FEM), random-effect model (REM) and general least squares method (GLS). The results reveal that, with interaction variable between the ratio of equity to total assets and foreign ownership, the national GDP annual growth rate is negatively associated with credit risk. With the ratio of equity to total assets, the interaction variable between equity and state ownership, and bank size have a significant positive impact on credit risk. In addition, inflation has negligible impact on the credit risk of commercial banks in Vietnam over the research period. The findings of this study suggest that, if foreign-owned banks increase equity capital, there will be a stronger impact on reducing credit risk than other banks. On the other hand, when state-owned commercial banks in Vietnam increase equity, they will have higher credit risk.