• Journal of Preventive Medicine and Public Health
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• v.38 no.3
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• pp.298-306
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• 2005

Objectives : To develop measurement scales of Internet addiction, and propose a Korean Internet Addiction Index (K-IAI) and classification criteria for Internet addiction from the threshold scores developed. Methods : The identification of the concept of 'Internet addiction' was based on the literature review. To select the scales, an exploratory factor analysis was applied. A construct validation was tested by a confirmatory factor analysis (CFA) with a structured equation model (SEM). In testing the validity of the classification criteria, ANOVA and non-recursive models with SEM were applied. Results : Out of 1,080 questionnaires distributed, 1,037 were returned,; a response rate of 96%. The Cronbach-$\alpha$ of all items was over 0.75. Using an exploratory factor analysis in the condition of a 6 factor constrain as the study model proposed, 23 of the initial 28 items were identified. In testing the discriminant and convergent validity of the selected 23 scales using CFA with SEM, the Internet addiction model explained about 93% of all variances of the data collected, and all the latent variables significantly explained the designated scales. A K-IAI was proposed using the T-scores of the sum of all factor averages. In the classification of users, the basic concept was a twostandard deviation approach of the K-IAI as the criteria of MMPI. The addiction group had a score ${\geq}70$ in the K-IAI, the pre-addiction group between ${\geq}50$ and <70, and the average user group <50. The Internet use times of the classified groups were statistically different in the ANOVA and multiple comparisons. Conclusions : The K-IAI is a reliable and valid instrument for measuring Internet addiction. Moreover, the taxonomy of the groups was also verified using various methods.

• Physical Therapy Korea
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• v.11 no.3
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• pp.59-70
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• 2004

The purpose of this study was to propose a task-related circuits program for stroke patients and to test the difference in functional improvements between patients undergoing conventional physical therapy and those participating in a task-related circuits exercise program. The subjects were 10 stroke in-patients of the Korea National Rehabilitation Center in Seoul. We measured the following variables: Motor Assessment Scale (MAS), Berg Balance Scale (BBS), Tone Assessment Scale (TAS), speed of gait, rate of step, physiological costs index, age, weight, height, site of lesion, onset day and whether the subject participated in an exercise program. Collected data were statistically analyzed by SPSS 10.0/PC using descriptive statistics, Mann-Whitney U test, Wilcoxon rank sum test and Spearman's correlation. The results of the experiment were as follows: (1) In the pre-test and post-test for function, there was not a statistical significance between the group partaking in a task-related circuits program and the group of conventional physical therapy (p>.05). (2) In the MAS, BBS and speed of gait test, the group undergoing conventional physical therapy showed a statistical significance (p<.05). (3) In the MAS, BBS, speed of gait, PCI, TAS (passive, associated reaction, TAS total score), the group of task-related circuits program showed a statistical significance (p<.05). As a result, the group participating in a task-related circuits program had a more functional improvement than the group participating in conventional physical therapy. Therefore, an intervention recommended for a stroke patient would be a task-related circuits program consisting of a longer session of each task for a more improved functional recovery.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.4
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• pp.378-386
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• 2013

In this paper, we propose a multi-way relaying system, in which N communicating nodes interchange their information one another by the help of a multiple-antenna non-regenerative relay station (RS). While the conventional multi-way relaying requires 2N transmission phases to complete the data exchange, the proposed system completes the mission with N phases composed of one multiple access phase and N-1 broadcast phases. For effective broadcast transmission, the proposed system pairs users for signal transmission with a new RS beamforming matrix not to interfere with the nodes of different pairs and a self-interference canceler at each node. The performance evaluation in terms of the average sum rate shows that the proposed system outperforms the conventional one with more significant gain when the number of RS antennas is comparable to the number of communicating nodes. The proposed schemes can be applicable to marine communications where the ships need to share their information with extended coverage.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.1
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• pp.21-25
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• 2004

From the gradual increasing state of charge (GISOC) observations, electrochemical behavior of multi-walled carbon nanotube│(lM LiP $F_{6}$ , EC,DEC,DME 3:5:5 volume ratio)│lithium cells was evaluated using the galvanostatic charge-discharge process. A MWCNT delivers a specific charge capacity of 1,300 mAh/g in a Li cell when cycled up to an end voltage of 0 V (vs. Li/L $i^{＋}$ )at a constant current rate every 10 hours. However, in the present study, the specific discharge capacity obtained is 338 mAh/g, thus amounting to a coulombic efficiency of only 26％. Further, when the MWCNT│Li cells were tested using the GISOC method, two distinguishable linear-fit ranges were observed due to the intercalation/deintercalation of lithium, which were found to have II $E_1$, IIC $s_1$ and II $E_2$of 27.3％, 372 mAh/g, and 25.5％, respectively. Q $c_1$, could be calculated from the data of IIE and IICs of each range by the modified equation "II $C_{sum}$= $\Sigma$( $Q_{C}$- $Q_{D}$)=(II $E_{1}$$^{-1}$ ) $Q_{Dl}$ ＋(II $E_2$$^{-1}$ -1) ( $Q_{D2}$- $Q_{Dl}$ ) ＋ IIC $s_1$= $Q_{Cl}$ - $Q_{Dl}$ ". Results of the GISOC method could be converted to the results of galvanostatic charge-discharge process, irrespective of the state of charge of the cell or battery.ery.y.y.

• Journal of Labour Economics
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• v.37 no.4
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• pp.25-57
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• 2014

Analysing the effects of expanded trade liberalization on the domestic labor market such as the flexibility of employment adjustment and the wage elasticity of employment etc. with industry base data, we get some important results as follows. The speed of employment adjustment in whole industries is turned out to be more rapid on the employee basis than on the whole worker basis. And the speed of employment adjustment is more rapid in the industries with high level of import ratio than those with high level of export ratio. In sum, viewing on the employee basis, the expanded trade liberalization makes the speed of employment adjustment slower slightly in individual industry level, and it is led mainly by the effects of export ratio rising. In case of the wage elasticity of employment, it becomes to be much higher as rates of openness or export ratios go higher, so the environment of jobless growth seems to be much more strengthened in this country.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.25-33
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• 2010

Introducing the quantized channel state information (CSI), space division multiple access (SDMA) can extract the multiplexing gain with the limited feedback burden. However, huge signaling burden of feedback can still suffer SDMA system because the total feedback data of SDMA is linearly dependent on the number of users. Hence, we propose a new feedback scheme to control the feedback load decided by the number of users. In this scheme, the cut-off level, which restricts the feedbacks of poor conditioned users, is suggested for the reduction of the feedback burden without the performance loss. From simulation results, then, we show that the proposed feedback scheme can achieve not only the sum-rate gain but also the reasonable feedback reduction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.1
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• pp.30-34
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• 1988

In roastal fish farms the farmers, especialy engaging in dealing with the floating cage culture, going to know about relationships between holding capacity and water quality in cage. Some of water quality managers and specialists studing physiological ecology understand that the key of water quality management concerned fish farming is budget of dissolved oxygen. This paper deals with oxygen budget in floating cage of the yellow tail farms at southern coastal area in Korea. The sampling station is located at Konli-Do fish farm near Chungmu, and the data is collected for 24 hours from 3:00 p.m. 8th September 1987. In result, the needed oxygen coming after the consumption by the rearing fish had been supplied with the tide current exchange, the sum of oxygen produced by phytoplankton photosynthesis and diffused from atmosphere are no more that $43\%$ for the needs of sea water consumption included respiration of planktons and decomposition of organic matters. The optimum holding capacity of cage is possible to compute with the calculation of minimum diurnal water exchange rate $[Qin{\cdot}V^{-1}\;(C-\bar{c})]$ through net mesh of cage.

• Journal of the Korean Dietetic Association
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• v.1 no.1
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• pp.66-78
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• 1995

The purposes of this study were to a) analyze the dietitian's job as a foodservice manager in employee foodservice, b) examine the performance and importance levels of management activities, c) determine factors affecting performance and importance levels of management activities. A job analysis questionnaires were developed and mailed to 65 dietitians who were members of The Korean Dietetic Association Practice Group, members with management responsibilities in employee foodservices. Completed questionnaires were received from 32 dietitians for a response rate of 49%. The questionnaire contained two parts with a total of 99 statements. Statistical data analysis was completed using the SAS programs for descriptive analysis, Wilcoxon signed ranks test, Wilcoxon rank sum test, and pearson correlation. The results of this study can be summarized as follows. 1. The average score of performance and importance levels on management activities were 3.11, 3.99 respectively. And they were significantly different(p<0.001). 2. The performance level was significantly correlated to working hours per week(r= .6598, p<.01), number of meals(r=.3934, p<.05) and foodcost(r=.5208, p<.05). 3. The importance level on management activities was significantly correlated to working hours per week(r=.6214, p<.05), number of meals(r= .4161, p<.05) and foodcost (r =.6920, p<.01).

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.1
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• pp.91-97
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• 2016

This study is concerned about the process capability index in single process. Previous process capability indices have been developed for the consistency with the nonconforming rate due to the process target value and skewness. These indices calculate the process capability by measuring one spot in an item. But the only one datum in an item reduces the representativeness of the item. In addition to the lack of representativeness, there are many cases that the uniformity of the item such as flatness of panel is absolutely important. In these cases, we have to measure several spots in an item. Also the nonconforming judgment to an item is mainly due to the range not due to the standard variation or the shift from the specifications. To imply the uniformity concept to the process capability index, we should consider only the variation in an item. It is the within subgroup variation. When the universe is composed of several subgroups, the sample standard deviation is the sum of the within subgroup variation and the between subgroup variation. So the range R which represents only the within subgroup variation is the much better measure than that of the sample standard deviation. In general, a subgroup contains a couple of individual items. But in our cases, a subgroup is an item and R is the difference between the maximum and the minimum among the measured data in an item. Even though our object is a single process index, causing by the subgroups, its analytic structure looks like a system process capability index. In this paper we propose a new process capability index considering the representativeness and uniformity.

• Journal of Korean Medicine for Obesity Research
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• v.8 no.1
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• pp.53-61
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• 2008

Objectives We have investigated a questionnaire on syndrome differentiation pertaining to obesity. To calculate data from this questionnaire, we can simply sum up the degree of symptoms. However, this does not reflect the difference in contribution of syndrome differentiation. In order to improve the level of precision of this questionnaire, we gather the weight of each symptom from experts and apply them to overweight persons. Method Nine Experts from The Society of Korean Medicine for Obesity Research nominated weights for the symptoms. We created a program based on weight survey results and applied to 1487 overweight persons and 26 oriental medical doctors. The concordance rate between the result obtained from the oriental medical doctors and that obtained using three methods was analyzed. Results 1. The reliability of this questionnaire is very high (Cronbach' ${\alpha}$=0.963). 2. The concordance level between diagnosis by oriental medical doctors and the result of general calculation is 0.347, between diagnosis by oriental medical doctors and the result of weighted calculation by syndrome differentiation is 0.362, between diagnosis by oriental medical doctors and the result of weighted calculation by symptoms is 0.1. Conclusions Weighted calculation by syndrome differentiation is relative more appropriate among three methods studied.