• Journal of applied mathematics & informatics
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• v.28 no.3_4
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• pp.723-737
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• 2010

In this paper, we investigate the sampling theorem for frame in multiwavelet subspaces. By the frame satisfying some special conditions, we obtain its dual frame with explicit expression. Then, we give an equivalent condition for the sampling theorem to hold in multiwavelet subspaces. Finally, a sufficient condition under which the sampling theorem holds is established. Some typical examples illustrate our results.

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

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.86-89
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• 2003

To model a numerical problem space under the limitation of available data, we need to extract sparse but key points from the space and to efficiently approximate the space with them. This study proposes a sampling method based on the search process of genetic algorithm and a space modeling method based on least-squares approximation using the summation of Gaussian functions. We conducted simulations to evaluate them for several kinds of problem spaces: DeJong's, Schaffer's, and our original one. We then compared the performance between our sampling method and sampling at regular intervals and that between our modeling method and modeling using a polynomial. The results showed that the error between a problem space and its model was the smallest for the combination of our sampling and modeling methods for many problem spaces when the number of samples was considerably small.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.594-604
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• 2017

The Korean National Institute of Fisheries Science (NIFS) has biannually (spring and fall, respectively) deployed a bottom trawl survey along the coastal areas for last decade, taking samples on a regular basis (i.e., a systematic sampling). Despite the availability of the survey data, NIFS has not yet officially reported the estimates of the groundfish population sizes as well as has not evaluated uncertainty of the estimates. The objectives of our study were to infer the relative size of a fish population, applying two different sampling techniques (namely simple and stratified sampling) with different observation units to the NIFS survey data, and to compare those two techniques in bias and precision. For demonstration purposes, we used data on Pacific cod (Gadus macrocephalus) collected by the 2011-2015 surveys, and the results of simple and stratified sampling showed that the point estimates and precision varied by observation unit as well as the sampling technique.

• Journal of the Korean Statistical Society
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• v.8 no.2
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• pp.165-168
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• 1979

For crops that are planted in a lattice layout, sampling designs can be made to take advantage of this regular arrangement. In order to select which tobacco plants to be examined in a survey to estimate disease loss in tobacco a method of, so called, bent plots was devised based on the regularity of plantings in the tobacco fields. We will first describe this sample selection and measurement method and then provide estimators and their bias and variance properties.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.24
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• pp.187-192
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• 1991

We consider a filling process problem on a production line. Up to present this problem have examined by 100% inspection. Thus a target value is determined which takes into account the regular selling prices, the reprocess cost, the excess quality cost and the process variability and so on. However, in this paper we propose a solution under specified sampling plan when the inspection is nondestructive.

• Journal of Korean Public Health Nursing
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• v.33 no.2
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• pp.270-283
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• 2019

Purpose: The aim of this study was to identify the job insecurity, job satisfaction, and organizational commitment of non-regular visiting nurses working at public health centers, and evaluate the effects of job insecurity on the job satisfaction and organizational commitment. Methods: This study was a descriptive survey study. One hundred forty-three visiting nurses, who were non-regular hired by 16 public health centers in B city, were selected using a convenient sampling method. Results: The results were analyzed using SPSS/Win 21.0. A feeling of helplessness (among job insecurity factors) and retention intention significantly affected the job satisfaction of non-regular visiting nurses, and their explanation power was 20%. Retention intention, a feeling of helplessness, and age significantly influenced the organizational commitment, and their explanation power was 26%. Conclusion: Therefore, it would be necessary to stabilize the employment type, provide appropriate promotion and compensation for nurses according to their work performance, and reduce the number of non-regular employees to increase the job satisfaction and organizational commitment of non-regular visiting nurses.

• Journal of the Ergonomics Society of Korea
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• v.27 no.3
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• pp.53-60
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• 2008

The work-related musculoskeletal disorders have constantly increased since it became an issue in 1996. In 2002, the Government established the risk factors analysis system in order to prevent musculoskeletal disorders. The proclamation by the Ministry of Labor defined eleven spheres of work associated with musculoskeletal disorders. As a result, business proprietors, who have workers engaged in tasks associated with musculoskeletal disorders, are required to conduct the risk factor analysis on a regular basis every three years. However, numerous issues have been raised while carrying out the risk factor analysis in various industries. One of the issues is that even though work sampling is an ideal method in risk factor analysis, most cases have selected extreme task postures, which is judged by an expert, due to limited time. This study will propose the desired direction of the risk factor analysis by comparing task assessment results between work sampling scenes and extreme task scenes.

• Korean Journal of Community Nutrition
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• v.24 no.5
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• pp.408-421
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• 2019

Objectives: This study compared the dietary behaviors of single-person households when eating alone according to the employment pattern and age. Methods: A total of 566 people aged 20~59 years old were collected from the status of workers and classified into three groups according to their employment pattern (regular, non-regular workers and business owner). The subjects were collected by purposive quota sampling on a Gallup panel from June to November in 2017. The dietary behavior and perception of eating alone of the subjects were surveyed via online and self-reported questionnaires. Results: The frequency of eating alone was significantly higher in the regular group than the non-regular group and business group (p<0.01). The place of eating alone was significantly higher in the regular and non-regular group in the convenience store, and business group in the office (p<0.001). Ramen, the menu when eating alone, was significantly higher in the non-regular group than the other groups (p<0.01). The preference for eating alone was lower in the older age group (p<0.05). The young aged group (aged 20~30) ate more fast food and felt more convenience than the older aged group aged 40~50 years (p<0.05). Conclusions: Single-person households with a non-regular job have poorer dietary behavior in eating alone than those who had regular employment. In a situation of an increasing number of non-regular workers aged in their 20s and 30s, there is a high likelihood of social problems, such as health and poverty. This study highlights the need for a healthy food selection environment to improve the dietary life of single-person households with non-regular jobs for the diverse types of single-person households.

• 한국노년학
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• v.28 no.4
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• pp.953-968
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• 2008

This research was performed to recognize anxiety level of older people, to find out anxiety level after or before regular exercises, and to find out how much anxiety level could be lowered by the sports activities. This research selected a population among the students who enrolled at sport activity classes (e, g., physical exercises, gate ball, volume dance) at L, S, J, Y (a), Y (b), D older people college located in Seoul and Gyoenggi area. 200 of the population were chosen as candidates by convenience sampling, nonprobability sampling. Considering the age of the candidates, total 200 cases were collected by using two methods (survey and interview) simultaneously. The data assessment was made by SPSS 12.0 Version. Error tolerance in statistics is .05. The data was analyzed by using frequency analysis, paired t-test and independent t-test. After analyzing anxiety awareness level after and before regular exercises, anxiety of older people are classified by four factors. First, anxiety for loss is 3.756 (M=3.756) before exercises, while 1.942 (M=1.942) after exercises. Second, fear for aging is 3.443 before exercises and 2.243 after exercises. Third, anxiety for physical appearance is 3.253 before exercises and 2.310 after exercises. Finally, anxiety caused by psychological insecurity is 3.060 before exercises, while 1.666 after exercises. Error of tolerance for all factors falls within .001. Anxiety score after exercises is lower than that of before exercises for every factor as well. As a result, regular physical exercises appeared to reduce anxiety level of older people.