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The Biomechanical Study on the Timings of Tkatchev Motion in Horizontal Bar (중고등학교 우수 선수의 철봉 Tkatchev 기술의 순간 동작 시점에 관한 운동역학적 연구)

  • Lim, Kyu-Chan
    • Korean Journal of Applied Biomechanics
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    • v.29 no.2
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    • pp.121-128
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    • 2019
  • Objective: The aim of this study was to examine the relation between swing phase and airborne phase of Tkatchev motion which was successfully performed with following motion by excellent middle and high school athletes in horizontal bar. Method: The subjects for this study were 8 male middle and high school top athletes. After their Tkatchev motions were filmed by two digital highspeed camcorders setting in 90 frames/sec at the 44th National Gymnastics against Cities and Provinces, the % lapse time lapse time of each instant, inferred maximum force acting on horizontal bar, and other kinematical variables were calculated through DLT method. After the relations among the % lapse times of each instants of downswing-start, downswing-finish, whipswing-finish, release, peak-height, and lapse time of regrasp, the relation among maximum force acting on bar, % lapse time, peak height, and the relation between % lapse time and release height were examined, the biomechanical timing characteristics of Tkatchev motion were as follows. Results: Firstly, it was revealed that the whole lapse time was $1.62{\pm}.06s$ and the correlation between the % lapse time of downswing-start and % lapse time of release was .819. Secondly, it was revealed that the pattern of COG path was shifted forwardly and tilted 11 clockwise from origin. Thirdly, it was revealed that maximum force acting on bar was inferred in $2,283{\pm}425N$ ($4.7{\pm}.6BW$) and the correlation between maximum force and peak height was r = .893. Lastly, it was revealed that the horizontal and vertical component of body COG velocity was $-2.14{\pm}.29m/s$, $2.70{\pm}.43m/s$ respectively, release height was $.49{\pm}.12m$, and shoulder angle was $139{\pm}5deg$, and that the later the % lapse time of release, the higher the release height (r = .935). Conclusion: It is desired that the gymnastic athletes should delay the downswing-start near the horizontal plane on $2^{nd}$ quadrant because the later the % lapse time of downswing, the higher the release height. After all the higher release height could ensure the athletes to regrasp the bar safely, the athletes should exercise to make downswing-start delay.

Impact of Youth Entrepreneurial Competency on the Success and Satisfaction of Start-ups through Entrepreneurial Self-Efficiency (청년창업가역량이 창업자기효능감을 매개로 창업성공과 창업만족에 미치는 영향)

  • Choi, Su Heyong;Kang, Hee kyung;Lee, Dae Shik
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.15 no.5
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    • pp.245-259
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    • 2020
  • The development of technology and the advent of a non-face-to-face society are expected to have a direct impact on job problems. In line with this phenomenon, the government and education and training institutions are coping with job problems through the start-up support policy while at the same time inducing the creation of innovative companies. In particular, youth start-up support can be expected not only to compensate for market failures, but also to promote high-growth start-ups. Based on this background of research, this study examined the competency of young entrepreneurs to start their own businesses, their entrepreneurial self-efficacy, and their impact on success and satisfaction of start-ups. Based on the theoretical research, the research theory and research model were derived by setting entrepreneurial self-efficacy as a mediating variable after reviewing the relation between the main elements of start-up competency of young start-up entrepreneurs and start-up performance. The Youth Entrepreneurship Competency was divided into four categories: Entrepreneurial Competencies, Technical Competencies, Management Competencies, and Creative Competencies, and the hypothesis was that each had a significant impact on the start-up performance through the mediating effect of entrepreneurial self-efficacy. A survey was conducted on young entrepreneurs in their 20s and 30s in Korea for empirical research, and the analysis results were as follows. First of all, the competency of young entrepreneurs to start their own businesses affects the success of start-ups and the satisfaction of start-ups. There are differences in the competencies, and both technical and management competencies can be seen through the entrepreneurial self-efficacy to enhance the success of start-ups and the satisfaction of start-ups. Entrepreneurial competency was fully mediated to start-up success and partially mediated to start-up satisfaction. In the case of creative competency, there were only direct effects on successful start-ups, and the satisfaction of start-ups showed partial mediating effects. Thus, seven of the eight detailed hypotheses were supported and one was rejected. Based on the above findings, the implications were presented.

Mini-Bin Based Implementation Complexity Improvement in Fair Packet Schedulers (공정 패킷 스케줄러에서 미니빈 기반 구현 복잡도 개선)

  • Kim, Tae-Joon;Kim, Hwang-Rae
    • Journal of Korea Multimedia Society
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    • v.9 no.8
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    • pp.1020-1029
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    • 2006
  • Realization of high-capacity quality-of-service router needs fair packet schedulers with a lower complexity. Timestamp based fair packet schedulers have the ideal complexity of O(log V), where V is the maximum number of admitted flows, but it has been recently reduced to O(1) using bin concept. However, the latency property was deteriorated and the bandwidth utilization was also declined. In addition, traffic flows requiring strong delay bound may not be admitted. To overcome these problems, this paper proposes a Mini-Bin based Start-Time (MBST) scheduler with variable complexity and evaluates its performance. The MBST scheduler uses the timestamp calculation scheme of start-time based schedulers to enhance the bandwidth utilization and also introduces mini-bin concept to improve the latency, The performance evaluation shows that the proposed scheduler can reduce the complexity of the legacy start-tine based schedulers by $1.8{\sim}5$ times without deteriorating the bandwidth utilization property.

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Design of Readout Circuit with Dual Slope Correction for photo sensor of LTPS TFT-LCD (LTPS TFT LCD 패널의 광 센서를 위한 dual slope 보정 회로)

  • Woo, Doo-Hyung
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.6
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    • pp.31-38
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    • 2009
  • To improve the image quality and lower the power consumption of the mobile applications, it is the one of the best candidate to control the backlight unit of the LCD module with ambient light. Ambient light sensor and readout circuit were integrated in LCD panel for the mobile applications, and we designed them with LTPS TFT. We proposed noble start-up correction in order to correct the variation of the photo sensors in each panel. We used time-to-digital method for converting photo current to digital data. To effectively merge time-to-digital method with start-up correction, we proposed noble dual slope correction method. The entire readout circuit was designed and estimated with LTPS TFT process. The readout circuit has very simple and stable structure and timing, so it is suitable for LTPS TFT process. The readout circuit can correct the variation of the photo sensors without an additional equipment, and it outputs the 4-levels digital data per decade for input luminance that has a dynamic range of 60dB. The readout rate is 100 times/sec, and the linearity error for digital conversion is less than 18%.

Leukocyte Sequestration and Free Radical-Mediated Lung Injury in Ovine Cardiopulmonary bypass Using Membrane Oxygenator (양에서 막형 산화기를 사용하여 심폐바이패스할 경우 백혈구격리 및 자유라디칼로 중재되는 폐손상)

  • 김원곤;신윤철;서정욱
    • Journal of Chest Surgery
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    • v.32 no.11
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    • pp.978-983
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    • 1999
  • Background: Complement activation with transpulmonary leukocyte sequestration is considered a main mediator leading to ischemia-reperfusion lung(I-R) injury. We studied the role of leukocytes in the formation of I-R injury in ovine cardiopulmonary bypass(CPB) model with a membrane oxygenator. Material and Method: Five sheep were used. CPB circuitry consisted of a roller pump(American Optical Corp., Greenwich, CT, USA) and a membrane oxygenator(UNIVOX-IC, Bentley, Baxter Health Corp, Irvine, CA, USA). The CPB time was fixed at 120 min. Ten minutes after the start of CPB, total CPB was established. Thereafter a total CPB of 100 min was performed, followed by another 10 min of partial CPB. The CPB was discontinued and the animals were fully recovered. For measuring left and right atrial leukocyte counts, blood samples were taken before thoracotomy, 5 min and 109 in after the start of CPB, and 30 min and 120 min after weaning. C3a was measured before thoracotomy, 109 min after the start of CPB, and 30 min and 120 min after weaning. Plasma malondialdehyde(MDA) was checked before thoracotomy, 109 min after the start of CPB, and 30 min after weaning. One to two grams of lung tissue were taken for water content measurement before thoracotomy, 109 min after the start of CPB, and 30 min after weaning. Lung biopsy specimens were examined by light and electron microscopy. Result: Of 5 animals, 4 survived the experimental procedures. Of these, 3 animals survived on a long-term basis. No significant differences in transpulmonary gradients of leukocyte were found and no significant complement activation was expressed by C3a levels. MDA level did not show significant changes related to lung reperfusion despite an increase after the start of CPB. On both light and electron microscopic examinations, mild to moderate acute lung change was observed. Interstitial edema, leakage of erythrocytes into the alveolar space and endothelial cell swelling were the main findings. Water content of the lung showed a slight increase after the start of CPB, but there was no statistical significance. Conclusion: These findings indicate that ischemia-repersusion lung injury may not be from complement activation-leukocyte sequestration but from another source of oxygen free radicals related to CPB.

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The Relationship between Collaboration Professor and Start-up of Undergraduate Students (산학협력중점교수와 대학생 창업 간의 관계)

  • Jung, Hyejin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.8
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    • pp.228-234
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    • 2020
  • The number of collaboration professors has significantly increased since the last decade, along with rapid technological developments and the necessity of entrepreneurial universities. Despite the expansion of collaboration professor recruitment, few empirical studies have examined the contribution of collaboration professors to university-industry collaboration. In particular, we do not have sufficient knowledge about the role of collaboration professors in the start-ups of undergraduate students, which is one of major duties of these professors. Following previous studies, this study constructs panel data of 203 universities explaining the proportions of collaboration professors, activities of undergraduate students, support of universities for students preparing new firms, and attributes of universities from 2017 to 2019. The results indicate that the percentage of collaboration professors is not statistically related with the start-ups of undergraduate students, whereas that of full-time professors working at organizations specializing in start-ups is positively and significantly associated with the number of new firms of undergraduate students. In addition, the percentage of students who had attended the start-up camps and the availability of financial support from universities for students who attempt to create new firms positively influence the start-ups of undergraduate students.

A Survey on the Current Status of Management of Fashion Start-up Companies by the Rising Fashion Designers (신진디자이너의 패션스타트업 기업운영 실태조사 연구)

  • Ji, Hye Kyung;Kim, Bock Hee
    • Journal of the Korean Society of Costume
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    • v.67 no.2
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    • pp.131-146
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    • 2017
  • The aim of this study is to investigate the operating characteristics of fashion start-up companies and the characteristics of their founders. For this purpose, this study surveyed fashion start-up companies via online survey in May 2015, and analyzed the data from one hundred companies. The results are as follows. First, for the characteristics of the founders, female founders constituted 65.0% and male founders 35.0%. At the time of establishment, founders aged 26-35 constituted 77.0%. Founders with less than five years of work experience made up about 80%. 82.1% of the founders participated in domestic and foreign exhibitions/fairs. 41.0% of the founders were awarded fashion contest and competition awards, and 33.3% of the founders were supported by rising designer support projects. Second, for the operating characteristics of the start-up companies, clothing at 78.0% was the most popular entrepreneurial item, and the majority targeted the age 20-30 group. 78.0% of the companies had less than 40 production styles per season, and all the enterprises had less than 5 employees. 59.0% of the companies had export experience. Exports to China, Hong Kong, and Japan accounted for 67.4% of all exports. Major distribution channels were mainly select shops(offline select shops 79.8%, online select shops 62.8%). The main methods of promotion were fashion media articles/interviews, product sponsorship, and SNS. The most preferred distribution channel was becoming a part of online/offline select shops(92.6%). Viral marketing(84.4%), star marketing and costume sponsorship(66.7%) were the most preferred method of promotion. The most preferred way to enter foreign markets was to participate in domestic and foreign exhibitions/fairs/trade shows. This study provides basic data necessary for future founders preparing to launch fashion start-up companies. It also aids fashion start-up companies in developing more advanced business operation strategies.

The Impact of the Characteristics of Start-up CEOs on the Amount of Investment in Series A Round (스타트업 CEO 특성이 시리즈 A 투자단계 벤처기업의 투자금액에 미치는 영향)

  • Choi, Sung-Woo;Han, In-Goo;Yoon, Byung-Seop
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.4
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    • pp.17-30
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    • 2022
  • The purpose of this study is to analyze the impact of the characteristics of start-up CEOs on the performance of investment attraction from the perspective of Series A investment. The results of the study are as follows. First, when the educational level of start-up CEOs was high and startup CEOs had start-up experience and investment attraction experience, venture investors such as venture capital had a significantly positive (+) effect on the investment for start-ups. This was systematically significantly positive even when control variables were introduced. When start-up CEOs had work experiences, there was no significantly positive effect on the total investment amount for start-ups but a significantly positive (+) effect on the average investment amount. Second, the standardization coefficient of total investment amount was larger in the case of start-up experience than that in the case of investment attraction experience while the standardization coefficient of average investment amount was larger in the case of investment attraction experience than that in the case of start-up experience. This suggests that the start-up experience is important for the total investment amount while the investment attraction experience is important for the average investment amount. Third, when the sales of start-ups were high at the time of Series A investment, the total investment amount and the average investment amount were also significantly high. Even if early start-ups are less profitable or have losses, the start-ups with a certain level of sales seem to be attractive investment targets for venture capital. The results of this study are useful for the investment decisions of venture capital and the financing strategies of start-ups. The implications for pre-CEOs preparing for start-ups art that the total amount of investment will increase if they have expertise through degree acquisition, challenge start-ups, gain start-up experience and implement investment attraction. Even if CEOs of start-ups do not have start-up experience, the average amount of investment for start-ups can increase if they have work experience in related industries.

Fast Booting of Linux Kernel using Dynamic IDE Device Probing Scheme (동적 IDE 장치 검사 기법을 이용한 리눅스 커널의 빠른 부팅)

  • Kim, Young-Ju
    • The Journal of the Korea Contents Association
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    • v.7 no.1
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    • pp.139-146
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    • 2007
  • Most of embedded systems have been developed practically based on the PC platform equipped with Intel x86 CPU since it is able to reduce the total time for product development and improve the reliability of product by making use of a variety of solutions developed for a long time in the PC environment. Also, embedded systems based on PC-platform mainly use a high-capacity hard disk as data storage device for applications intending to store multimedia data. Recently, while the capacity of hard disk is increasing rapidly, the start-up ready time of hard disk is growing longer more than 30 seconds. The lengthened start-up ready time may delay the booting time of embedded system seriously, weighting users down with inconvenience. This paper proposes the refined system architecture and the dynamic IDE device probing method for fast booting of linux kernel in the embedded system based on PC platform with high-capacity hard disks, and the performance of proposed methods is evaluated and presented.

A Time-to-Digital Converter Using Dual Edge Flip Flops for Improving Resolution (분해능 향상을 위해 듀얼 에지 플립플롭을 사용하는 시간-디지털 변환기)

  • Choi, Jin-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.7
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    • pp.816-821
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    • 2019
  • A counter-type time-to-digital converter was designed using a dual edge T flip-flop. The time-to-digital converter was designed with a $0.18{\mu}m$ CMOS process at a supply voltage of 1.5 volts. In a typical time-to-digital converter, when the period of the clock is T, a conversion error corresponding to the period of the clock occurs due to the asynchronism between the input signal and the clock. However, the clock of the time-to-digital converter proposed in this paper is generated in synchronization with the start signal which is the input signal. As a result, conversion errors that may occur due to asynchronization of the start signal and the clock do not occur. The flip-flops constituting the counters are composed of dual-edge flip-flops operating at the positive and negative edges of the clock to improve the resolution.