• Journal of the Korean Arthroscopy Society
• /
• v.1 no.1
• /
• pp.41-46
• /
• 1997

The natural history of the anterior cruciate ligament(ACL)-deficient knee remains controversial. although numerous investigation have tried to ascertain the course that the knee would follow once the ACL has lost functional integrity. An extensive review of the literature performed according to symptoms. physical examinations, associated surrounding tissue injuries. returns to activity level and radiological changes in the knee joint. An active individual with a non-functioning ACL was susceptible to injury to the menisci and deteriorate the articular cartilage, followed radiographic changes. An activity levels in general also changed after injury. The most common symptom was pain. But instability varied in these individuals. Conclusively we believe that all these factors will eventually, if not initially, result in a symptomatic knee. which will result in significant limitations to the individual's desired level. So we recommend an aggressive approach in person who desired to return to a relatively active life style in young person as well as in middle aged individuals who have significant symptomatic ACL deficient knee.

• The Journal of Korean Physical Therapy
• /
• v.12 no.2
• /
• pp.219-228
• /
• 2000

Successful return to work or athletic sports after rehabilitation of an orthopeadic condition and sports injury of the lower extremities requires that the therapist understand the mechanical requirements of high level Physical activity. High level Physical activity need resistance exercise Program in the treatment approaching methods. One of them, the plyometrics training is the best way that will be magnifing the musculotendon unit. So it is important understanding of biomechanics and neurophysiology of plyometrics.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.182.2-182.2
• /
• 2012

If the satellite has the magnetic material or magnetic moment, the satellite is affected by the earth magnetic field by the space environment in Geostational orbit. The aim of this paper is to assess the satellite magnetic momentum which is an input to ADCS(Altitude Determination Control Subsystem) analyses to assess spurious torques. The magnetic momentum at satellite level is due to magnetic momentum generated by each unit which is due to internal currents circulation or to the presence of magnetic components. Also the magnetic momentum at satellite level is due to circulation of the DC supply current from PSR(Power Supply Regulator) to each unit. As introducing the intrinsic contribution of each unit and the magnetic moment based on the current return through the structure, this paper assess the satellite magnetic moment.

• Journal of Korean Academy of Nursing
• /
• v.41 no.3
• /
• pp.393-402
• /
• 2011

Purpose: This study was done to assess the educational needs that should be considered in developing curriculum for staff in charge of public health services in public hospitals. Methods: The participants in this study were staff in charge of public health services in 130 public hospitals. The Borich's Needs Assessment Model which analyzed the relation of 'required competence level' and 'present competence level', was utilized. Data were collected from October to November 2007 using a structure self-report questionnaire. The return rate was 66.9%. The Cronbach's alpha score was 0.959. Results: The mean scores for 'required competence level', 'present competence level' and Borich's need were 4.02, 3.44, and 2.30 respectively. According to public health service items, 'strategies to recognize the present condition and analyze problems' had the highest score for Borich's need, but 'establishment of annual or monthly objectives' had the lowest score for Borich's need. Conclusion: Education was found to be very important for staff carrying out public health services. Ultimately the results of this study may be utilized to develop education program for staff carrying out public health services in public hospitals.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.21 no.3
• /
• pp.224-229
• /
• 2009

Partial safety factors(PSFs) for Level I reliability based design of caisson type quay walls were calculated. First order reliability method(FORM) based PSFs are the functions of sensitivities of limit state function with respect to design random variables, target reliability index, characteristic values and first moment of random variables. Modified PSFs for water level and resilient water level are newly defined to keep consistency with the current design code. In the numerical example, PSFs were calculated by using a target reliability index. Seismic coefficient is defined to show extreme distribution. It was found that PSFs for seismic coefficient becomes smaller as the return period for design seismic coefficient grows longer.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.29 no.1
• /
• pp.82-91
• /
• 2021

The topic of this paper was analyzed as "t -test" and "multiple regression analysis" for 303 helicopter pilot trainees from aviation schools in the county for "improvement of education through correlation analysis of helicopter pilots' situational awareness and education satisfaction." In addition to the factors for overcoming situational awareness and situational awareness, the level of satisfaction of the instructor and the level of satisfaction of the learning management system (LMS) is the confidence interval p<.05, 95%. It was analyzed to be significant at the level of 05, 95%. Therefore, it was analyzed that in order to improve the "quality of the instructor" in future education, institutional supplementation and "learning management system (LMS)" need to be established including VR and AR so that pilot trainees can use it at all times.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.2 no.4
• /
• pp.103-133
• /
• 2007

The purpose of this study is to investigate whether customer satisfaction is affected by the expenditure for the customer satisfaction such as advertising, promotion, and training. This study also investigate whether the financial performance of the firm is affected by the customer satisfaction. The major findings are summarized as following. First, the customer satisfaction is affected by the expenditure for the customer satisfaction such as promotion, training. But customer satisfaction is not affected by advertising cost. Second, considering the time-lag and incremental valiables, the relationship between customer satisfaction and expenditure for the customer satisfaction is not founded. Third, the customer satisfaction affects positively on the corporate financial performance, such as ratio of operating income to sales, ratio of net income to sales, return on total assets, and return on equity. Finally, considering the time-lag the relationship between customer satisfaction and financial performance is not founded. Considering the incremental valiables, the relationship between customer satisfaction and financial performance is founded when ratio of operating income to sales and return on total assets are used financial performance. These findings imply that the expenditure for promotiom and training is needed to increase the customer satisfaction. Also improvement customer satisfaction is needed to increase the financial performance. The limitations of this study are as following. First, this study could not consider the other variables that would affect on the relationship among expenditure for customer satisfaction, level of customer satisfaction, and financial performance. Second, the results of this study are difficult to generalize because this study is focused on the service industry.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.22 no.3
• /
• pp.191-201
• /
• 2010

The breakwaters are designed by considering the cost optimization because a human risk is seldom considered. Most breakwaters, however, were constructed without considering the cost optimization. In this study, the optimum return period, target failure probability and the partial safety factors were evaluated by applying the cost optimization to the rubble mound breakwaters in Korea. The applied method was developed by Hans F. Burcharth and John D. Sorensen in relation to the PIANC Working Group 47. The optimum return period was determined as 50 years in many cases and was found as 100 years in the case of high real interest rate. Target failure probability was suggested by using the probabilities of failure corresponding to the optimum return period and those of reliability analysis of existing structures. The final target failure probability is about 60% for the initial limit state of the national design standard and then the overall safety factor is calculated as 1.09. It is required that the nominal diameter and weight of armor are respectively 9% and 30% larger than those of the existing design method. Moreover, partial safety factors considering the cost optimization were compared with those calculated by Level 2 analysis and a fairly good agreement was found between the two methods especially the failure probability less than 40%.

• The Korean Journal of Financial Management
• /
• v.26 no.1
• /
• pp.165-188
• /
• 2009

This paper has suggested the methodology for the frontier portfolios and the optimal portfolio under the mean-VaR framework, not assuming the normal distribution and considering the investor's preferences for the higher moments of return distributions. It suggested the grid and rank approach which did not need an assumption about return distributions to find the frontier portfolios. And the optimal portfolio was selected using the utility function that considered the 3rd and the 4th moments. For the application of the methodology, weekly returns of the developed countries index, the emerging market index and the KOSPI index were used. After the frontier portfolios of the mean-variance framework and the mean-VaR framework were selected, the optimal portfolios of each framework were compared. This application compared not only the difference of the standard deviation but also the difference of the utility level and the certainty equivalent expressed by weekly expected returns. In order to verify statistical significances about the differences between the mean-VaR and the mean-variance, this paper presented the statistics which were obtained by the historical simulation method using the bootstrapping. The results showed that an investor under the mean-VaR framework had a tendency to select the optimal portfolio which has bigger standard deviation, comparing to an investor under the mean-variance framework. In addition, the more risk averse an investor is, the bigger utility level and certainty equivalent he achieves under the mean-VaR framework. However, the difference between the two frameworks were not significant in statistical as well as economic criterion.

• The Journal of the Korea Contents Association
• /
• v.21 no.11
• /
• pp.320-332
• /
• 2021

This paper investigates the influence of stock-level left-tail risk, which is defined using Value-at-Risk(VaR) estimates of past one-year daily stock returns, in the expected stock returns in the Korean stock market. Our results are summarized as follows: First, monthly-constructed zero-cost portfolios that buy (shortsell) the highest (lowest) left-tail risk decile in the previous month exhibit an average monthly return (called left-tail risk premium) of -2.29%. Second, Fama-MacBeth cross-sectional regressions suggest that left-tail risk in the previous month shows significant and negative explanatory power over return in this month, after controlling for various firm characteristics such as firm size, B/M, market beta, liquidity, maximum daily return, idiosyncratic volatility, and skewness. Third, the stocks with larger recent month loss have lower returns in the next month. Fourth, the magnitude of left-tail risk premium is negatively related with lagged market-level volatility. These results support the hypothesis from a perspective of behavioral finance that the overpricing of stocks with left-tail risk is attributed to the investors' underreaction to it.