• Journal of applied mathematics & informatics
• /
• v.18 no.1_2
• /
• pp.145-158
• /
• 2005

We formulate a stochastic control problem on proportional reinsurance that includes impulse and regular control strategies. For the first time we combine impulse control with regular control, and derive the expected total discount pay-out (return function) from present to bankruptcy. By relying on both stochastic calculus and the classical theory of impulse and regular controls, we state a set of sufficient conditions for its solution in terms of optimal return function. Moreover, we also derive its explicit form and corresponding impulse and regular control strategies.

• Transactions on Control, Automation and Systems Engineering
• /
• v.4 no.2
• /
• pp.147-155
• /
• 2002

In this paper, the regular rotational gaits of the quadruped crawling robot are studied. It is assumed that the proposed regular rotational gaits starts from one of six support patterns in a translational gaits and end up with one of six support patterns in a translational gaits. Noting that six support patterns in a regular translational gait belong to two different groups with respect to regular rotational gait, the static stability margin and the maximum rotational displacement during one rotational stride period for the two representative support patterns are investigated. It is expected that the proposed regular rotational gaits will enhance the omni-directional characteristics of the quadruped crawling robot.

• Korean Journal of Digital Imaging in Medicine
• /
• v.12 no.2
• /
• pp.71-79
• /
• 2010

Thanks to the great development of technology in radiation, we are now able to reduce radiation exposure to the patients, and the radiographer and expenses in medical sector. We are also trying to produce ideal images which maintain useful information. These kinds of effort are increasing over the world. For that reason, we should get images which include necessary data of patients. Then it also can help to reduce radiation exposure to the patients. Therefore, we need to know the problems that cause a falling off in image's quality and check on generator in case of their electronic and mechanical errors. And moreover, we should anticipate the possibility of devices errors and prevent them with regular quality control. This investigation was conducted in medical institutions, institute of educations and hospitals. They are all in Seongnam-City. We used PMX-III, kVp meter to implement kVp test, mR / mAs output test, light fiel / beam alignment test, Reproducibility of exposure dose, half value layer test, reproducibility of exposure time test. in the case of hospitals, they perceive the importance of regular quality control and organize the regular quality control team so they can be satisfied with the error standard in most experiments. On the other hand, when it comes to medical institutions and institute of educations, they perceive the importance of regular quality control less than hospitals do. Radiographer need to understand the importance of regular quality control and practice it so they can get the fine ideal image with the lower dose to the patient.

• Journal of Labour Economics
• /
• v.30 no.2
• /
• pp.1-31
• /
• 2007

The purpose of this paper is to analyse wage differentials between non-regular and regular works. Data from EAPS(Economically Active Population Survey) 2005 show that the monthly wage level of non-regular worker is only 63% of regular worker and thus there exist 37% wage differentials. However, these wage differentials do not control for hours of work, the amount of human capital, job characteristics, and other individual characteristics affecting wages. If these variables are added to the hourly wage regression equation, the wage gap between non-regular and regular workers drastically decreases to 2.2%. Furthermore, decomposition of the wage differentials by Oaxaca method shows that productivity difference between non-regular and regular workers explains up to 91% of the wage gap. This implies that the magnitude of wage discrimination against non-regular workers is at most 0.2% of hourly wage of regular workers. To control for unobserved individual heterogeneities more accurately, we also construct panel data and estimate wage differentials. The results from the panel data approach show that there is no difference in the hourly wages between non-regular and regular workers. In some specifications, the wage rate of non-regular worker is rather higher than that of regular worker. These results are consistent with economic theory. Other things being equal, workers with unstable employment may require higher wages to compensate their unstability. Firms are willing to pay higher wages if they can get more flexibility from non-regular employment. Empirical results in this paper cast doubt on the view that there is wage discrimination against non-regular workers in the labor market. Public policies should be targeted for disadvantaged groups among non-regular workers, not for non-regular workers in general.

• Journal of the Korean Society of Food Culture
• /
• v.27 no.1
• /
• pp.38-48
• /
• 2012

This study was conducted to examine dietary behaviors according to residence status and ethnicity of university students in Yanbian, China. For the subjects, 334 university students (Male=141, Female=193) answered a questionnaire about perception of weight control, dietary patterns, health habits, residence status, and ethnicity. Perception of weight, meal frequency, favorite kind of food, meal finishing time, skipping breakfast, type of breakfast, snack frequency, late-night snack frequency, exercise frequency, regular life, and sleeping time were all significantly associated with residence status. Motivation of weight control, meal frequency, regularity of meal time, meal volume, favorite kind of food, exercise time, and regular life were all significantly associated with ethnicity. University students who lived with their parents perceived their weight more properly, exhibited a more positive dietary pattern, and lived a more regular life than those students who lived in a dormitory with their friends. Chinese students exhibited a more regular dietary pattern and lived a more regular life than the Korean-Chinese students. As a result, both environmental and inherent factors are related with the dietary behaviors of university students in Yanbian, China. These data could be used to help university students in Yanbian, China attain a healthy diet.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10b
• /
• pp.425-429
• /
• 1992

Point sets in the Euclidean and digital planes are discussed. The local necessary and sufficient conditions are suggested for pointed lattice extraction from these sets are presented. A number of theorems and corollaries are given. The regular and "almost" regular point sets are studied. The results can be used in automatic control of textured textile images by both general and multiprocessing systems.g systems.

• Proceedings of the KIEE Conference
• /
• 1990.11a
• /
• pp.319-322
• /
• 1990

Self-controlled permanent magnet synchronous motor (PMSM) has similar operating characteristics as seperately excited dc motor. It is favored in servo applications due to its improvement of efficiency and maintenance. This paper presents completely digitalized controller using microprocessor and voltage fed inverter. The speed control system for PMSM is implemented. To control the motor speed, the control system regulates the magnitude of Inverter output voltage by regular-sampled PWM method to generate sinusoidal PWM wave with microprocessor. And to keep the range of inverter switching frequency, it varies the number of pulse train according to the speed.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.28 no.3
• /
• pp.274-285
• /
• 1992

Among various Power converters, a variable voltage variable frequency (VVVF) three-phase PWM inverter is regarded as most promising power converter due to its capabilities, which permits the control of voltage, frequency and harmonic contents in a single power stage employing only on DC source. As a modulating technique of the PWM inverter, the regular sampling technique has rendered possible the on-line computation and generation of PWM control waveforms with a reasonably high switching frequencies. In this paper, microprocessor based three-phase regular samping PWM inverter with real-time control algorithm and control circuits for driving three phase AC motor has been developed. Harmocic components of PWM waveform were analized theoretically in terms of Bessel function series and then calculated by digital computer and observed with spectrum analyzer.

• The Korean Journal of Food And Nutrition
• /
• v.25 no.3
• /
• pp.483-489
• /
• 2012

In this study, a survey was carried out on 208 students at middle schools in Gyeonggi-do through May 1 to July 20, 2011, with the purpose of figuring out how eating attitudes of middle school students affect their psychological achievement and self control. The results were as follows. First, the effect of eating attitudes on the psychological achievement of middle school students demonstrated that regular dietary life, dietary life and health had a statistically significant positive effect on psychological achievement. Second, the effect of eating attitudes on self control in middle school students showed that balanced dietary life, dietary life and health had a statistically significant positive effect on self control. The above findings confirmed that regular and healthy dietary life connected directly with health, which was a factor that makes them think positively about psychological achievement. Besides, for eating self control, as balanced dietary life in eating attitudes was important. And as this had a positive effect on their self control, could improve their eating attitudes. Consequently, the regular eating attitudes and balanced dietary life in eating attitudes of middle school students can make their psychological achievement and eating self control for the nutrition and health care.

• Journal of the Korean Society of School Health
• /
• v.22 no.2
• /
• pp.49-59
• /
• 2009

Purpose : The purpose of this study was to evaluate the effects of regular health education by school nurses on middle school student's health related knowledge, attitude and behavior. Methods : A quasi-experimental design with pretest and posttest measures was used. Questionnaire survey was conducted to middle school students(1st, 2nd year). The participants of the study were composed two groups : 274 in health education group and 336 in control group. Results : After seventeen-week of receiving regular health education, differences were observed between the experimental group and the control group to health knowledge(F=7.901, p=.005), health attitude(F=4.174, p=.042) and health behavior(F=7.675, p=.006). Conclusion : The regular health education by school nurses on middle school students improve their health related knowledge, attitude and behavior. So it is recommended to develop standardized manual and educational materials for providing systematic and effective health education.