• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.631-637
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• 2005

This paper presents a stiffness analysis method for a low-DOF parallel manipulator, which takes into account of elastic deformations of joints and links. A low-DOF parallel manipulator is defined as a spatial parallel manipulator which has less than six degrees of freedom. Differently from the case of a 6-DOF parallel manipulator, the serial chains in a low-DOF parallel manipulator are subject to constraint forces as well as actuation forces. The reaction forces due to actuations and constraints in each limb can be determined by making use of the theory of reciprocal screws. It is shown that the stiffness model of an F-DOF parallel manipulator consists of F springs related to the reciprocal screws of actuations and 6-F springs related to the reciprocal screws of constraints, which connect the moving platform to the fixed base in parallel. The $6{times}6$ stiffness matrix is derived, which is the sum of the stiffness matrices of actuations and constraints. The six spring constants can be precisely determined by modeling the compliance of joints and links in a serial chain as follows; the link can be considered as an Euler beam and the stiffness matrix of rotational or prismatic joint can be modeled as a $6{times}6$ diagonal matrix, where one diagonal element about the rotation axis or along the sliding direction is zero. By summing the elastic deformations in joints and links, the compliance matrix of a serial chain is obtained. Finally, applying the reciprocal screws to the compliance matrix of a serial chain, the compliance values of springs can be determined. As an example of explaining the procedure, the stiffness of the Tricept parallel manipulator has been analyzed.

• Journal of Korean Academy of Nursing
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• v.40 no.3
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• pp.400-410
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• 2010

Purpose: The purpose of this study was to investigate the factors that influenced the health-related quality of life of young-old (65-74 yr) men, old-old (75-84 yr) men, and oldest-old (85 yr or above) men in vulnerable aged received home care from public health center. Methods: The participants for this study were 318 aged Korean men living in D city. The data was collected from August to October, 2009 using structured questionnaires. Chi-square, One way ANOVA, Duncan test, Pearson's Correlation Coefficient and multiple regression with the SPSS WIN 14.0 program were used to analyze the data. Results: There were statistically significant differences among young-old, old-old, and oldest-old men regarding the health-related quality of life, health promoting behavior, IADL (Instrumental Activities of Daily Living), rehabilitation, depression, and social support. The model including variables related to physical, psychological, and social aspects of life, explained variance of the health-related quality of life of aged men differently, such as 39.6% of young-old, 35.4% of old-old, and 47.0% of oldest-old. Finally, IADL and social support were predictors in explaining the level of health-related quality of life among vulnerable old men regardless of age. Conclusion: Based on the findings of the study, nursing interventions should be developed to improve health-related quality of life of vulnerable aged men according to age differences.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.67.2-67.2
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• 2014

The presence of multiple populations is now well-established in most globular clusters in the Milky Way. In light of this progress, here we suggest a new model explaining the origin of the Sandage period-shift and the difference in mean period of type ab RR Lyrae variables between the two Oosterhoff groups. In our models, the instability strip in the metal-poor group II clusters, such as M15, is populated by second generation stars (G2) with enhanced helium and CNO abundances, while the RR Lyraes in the relatively metal-rich group I clusters like M3 are mostly produced by first generation stars (G1) without these enhancements. This population shift within the instability strip with metallicity can create the observed period-shift between the two groups, since both helium and CNO abundances play a role in increasing the period of RR Lyrae variables. The presence of more metal-rich clusters having Oosterhoff-intermediate characteristics, such as NGC 1851, as well as of most metal-rich clusters having RR Lyraes with longest periods (group III) can also be reproduced, as more helium-rich third and later generations of stars (G3) penetrate into the instability strip with further increase in metallicity. Therefore, although there are systems where the suggested population shift cannot be a viable explanation, for the most general cases, our models predict that the RR Lyraes are produced mostly by G1, G2, and G3, respectively, for the Oosterhoff groups I, II, and III.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.327-334
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• 2015

We investigated the current and potential spatial distributions and habitable areas of Biston robustum and Camellia japonica in South Korea in order to provide useful data for the conservation of C. japonica and minimize the damage caused by B. robustum. It was predicted that, by 2070, although B. robustum would be widely distributed throughout the Korean Peninsula, except for the western and eastern coastal areas, it would be narrowly distributed along the Sokcho-si and Goseong-gun coastlines in Gangwon Province. C. japonica is currently located along the southern coastline but its critical habitable area is predicted to gradually disappear by 2070. Assessment of the potential distribution probabilities of B. robustum and C. japonica revealed that the area under the curve (AUC) values were 0.995 and 0.991, respectively, which indicate high precision and applicability of the model. Major factors influencing the potential distribution of B. robustum included precipitation of wettest quarter and annual precipitation (BIO16 and BIO12), whereas annual mean temperature and mean temperature of wettest quarter (BIO1 and BIO8) were important variables for explaining C. japonica distribution. Overlapping areas of B. robustum and C. japonica were $11,782km^2$, $5447km^2$, and $870km^2$ for the current, 2050-predicted, and 2070-predicted conditions, respectively, clearly showing a dramatic decrease in area. Although it is predicted that B. robustum would cause continuous damage to C. japonica in the southern part of the Korean Peninsula, such impacts might diminish over time and become negligible in the future.

• Child Health Nursing Research
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• v.4 no.2
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• pp.255-264
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• 1998

Disease prevention and health promotions are basically needed to be healthy, health education is the most useful mean to accomplish them. Preschool children are being developped, their health problem can effect their health status through their lives. This study was attempted to survey for status of health education of kindergarten for preshoolers and to provide the basic precious data for nursing intervention. The subjects were 51 kidergarten teachers. The data were collected by the questionaires, which consiste of 25 items concerning daily life habits of children and 1 item concerning the problems of health education for preschoolers. The data were analyzed by SAS program. The results of this study are as folleowed ; 1. The most frequently educated subjects were 'adequate and safe play' and 'hand washing', 'walking and running straightly', 'oral hygiene or tooth brushing', 'walking staires'. 2. The most frequently used teaching method was the explaining. 3. The most frequently used instructional method was the pictures. The slide films and OHP was seldomly used media. 4. The most effective teaching method which perceived by the kindergarten teachers was role play . Discuss ion and compensation/reinforcement were comparatively effective method also. 5. The most effective instructional media which perceived by the kindergarten teachers was a real object/model. 6. The problems of health education for preschoolers were 'deficiency of developped health educational programs' and 'inconsistency between parents' education and kindergarten teachers' education', 'deficiency of instructional media'. The other problems were' the knowledge deficit of teachers themselves' and 'the difficulty of measure the effect of education', 'time deficit'. Conclusionally, we have to realize the health of children is the future of our health, and reinforce the health education for preschoolers to accomplish the disease prevention and health promotion.

• The Journal of Korean Academic Society of Nursing Education
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• v.18 no.2
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• pp.229-238
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• 2012

Purpose: The purpose of this study was to evaluate the theory of planned behavior (TPB) in the structural relationship of nursing students' performance related to nosocomial infection control (NIC). Method: Data was collected by using a questionnaire completed by 238 nursing students of three nursing colleges in Suwon, Sokcho. Results: The mean score of performance related to NIC was 3.86. The highest mean score of performance related to NIC was 4.18 (${\pm}0.91$) for 'hand washing' and the lowest mean score was 3.56 (${\pm}1.08$) for 'respiratory system'. In prediction of the intention of nursing students' on NIC, the attitude, the subjective norm, and the perceived behavior control(PBC) of TPB resulted in statistically significant influencing factors (p<0.050). These three variables explained 47.6% of the total variance of the intention of nursing students' on NIC. In predicting the performance related to NIC, the PBC resulted in the direct and main influencing factor of nursing students' performance related to NIC (p<0.010). Intention was not a significant determinant. These two variables explained 13.2% of total variance of the performance related to NIC. Conclusion: This study shows the TPB model's applicability in explaining performance related to NIC of nursing students and highlights the importance of PBC for strategies to enhance performance related to NIC in nursing students.

• Asia pacific journal of information systems
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• v.25 no.2
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• pp.211-238
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• 2015

Despite longstanding concern with the dimensionality of the service quality construct as measured by ServQual and IS-ServQual instruments, variations on the IS-ServQual instrument have been enduringly prominent in both academic research and practice in the field of IS. We explain the continuing popularity of the instrument based on the salience of the item set for predicting overall customer satisfaction, suggesting that the preoccupation with the dimensions has been a distraction. The implicit mutual exclusivity of the items suggests a more appropriate conceptualization of IS-ServQual as a formative index. This conceptualization resolves the paradox in IS-ServQual research, that of how an instrument with such well-known and well-documented weaknesses continue to be very influential and widely used by academics and practitioners. A formative conceptualization acknowledges and addresses the criticisms of IS-ServQual, while simultaneously explaining its enduring salience by focusing on the items rather than the "dimensions." By employing an opportunistic sample and adopting the most recent IS-ServQual instrument published in a leading IS journal (virtually, any valid IS-ServQual sample in combination with a previously tested instrument variant would suffice for study purposes), we demonstrate that when re-specified as both first-order and second-order formatives, IS-ServQual has good model quality metrics and high predictive power on customer satisfaction. We conclude that this formative specification has higher practical use and is more defensible theoretically.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.3
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• pp.101-119
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• 2011

A empirical study investigating firms' attitudes and behaviors regarding of RFID technology within supply chain is very limited. Thus, this study examines the determinants influencing firms' adoption and performance of RFID within the supply chain. Particularly, this study focus on the impacts of the companies' relationship characteristics, including strategic fit, interdependence, compatibility, and long-term orientation affection RFID adoption and performance within the supply chain. Furthermore, the study includes environment uncertainty as a moderating effect between relationship characteristics and RFID adoption. The proposed research model was tested using structural equation modeling from 227 employees. Results of this study support the proposed hypotheses. The implication of this study suggest a new theoretical framework explaining RFID adoption and performance with the supply chain.

• Journal of Fisheries and Marine Sciences Education
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• v.14 no.1
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• pp.57-73
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• 2002

Illegal fishing is often cited as a principal cause of the failure of fisheries management, expecially fishing efforts regulations in traditional fisheries management. Usually, illegal fishing problems are perceived to be equivalent to inadequate enforcement, and policy prescription then follow to strengthen enforcement programs. The purpose of this paper is to analyze the illegal fishing behavior relatively recent emphasis on fishing efforts regulations in traditional fisheries management. The analysis focuses on measuring, explaining and developing the effectiveness way of enforcement strategies responding to imperfectly managed fishing efforts regulations through illegal fishing behavior and avoid enforcement fishing efforts measures. A model of fishermen fishing behavior and profit-maximizing decision making is analyzed to determine optimal fishing at individual fisherman level in response to fishing efforts regulation. The results of economic analysis of the enforcement of illegal fishing in traditional fisheries management results are as follows: First, illegal fishing will occur only if enforcement effort is not so high as to remove the incentive to do so, and if the effectiveness of avoidance is not too great, nor its cost too low. Second, avoidance effort will occur at a level jointly proportional to the extent of illegal activity and of enforcement; for given levels of the latter, the desired avoidance effort increase with its effectiveness and decrease with its cost Third, to improve the effectiveness of enforcement, understanding avoidance behavior appears to be crucial to any efforts. Forth, enforcement and fishermen behavior interact depends strongly on characteristics of avoidance, specifically its cost and effectiveness. When avoidance is neither too cheap nor too effective, the interaction is regular. Fifth, in this case, at low levels of enforcement, fishers respond to increases in enforcement by increasing avoidance, but at higher enforcement levels, it becomes uneconomical to continue to do so, and avoidance decreases with enforcement. Sixth, illegal fishing activity decreases steadily with enforcement, so the fishery manager is able, in theory, to reduce illegal fishing toward zero by increasing enforcement. If, however, avoidance is very inexpensive and/or very efficient/ then the optimal level of avoidance will increase indefinitely with increasing enforcement. Finally, less fishery enforcement is required if fishermen have less incentive to overfish, and fishermen have less incentive to avoid fishery enforcement measures.

• International Journal of Highway Engineering
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• v.19 no.5
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• pp.143-151
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• 2017

PURPOSES : The purpose of this study is to develop models of accidents occurring at circular intersections related to the time of day and night and driver gender, and to provide countermeasures for safer circular intersections. METHODS : Seventy intersections built before 2008 were surveyed for inclusion in the modeling. Traffic accident data from 2008 to 2014 were collected from the TAAS data set of the Road Traffic Authority. Sixteen variables explaining the accidents including geometry and traffic volume were selected from the literature and seven multiple linear regression models were developed using SPSS 20.0. RESULTS : First, the null hypotheses, that the number of traffic accidents are not related to driver gender or time of day, were rejected at a 5% level of significance. Second, seven statistically significant accident models with $R^2$ value of 0.643-0.890 were developed. Third, in daytime models by gender, when the right-turn-only lane was selected as the common variable, the number of lanes, presence of driveways and speed humps, diagrammatic exit destination sign, and total entering traffic volume were evaluated as specific variables. Finally, in nighttime models by gender, when the diagrammatic exit destination sign was selected as the common variable, total entering traffic volume, presence of right-turn-only lanes, number of circulatory road way lanes, and presence of splitter islands and driveways were identified as specific variables. CONCLUSIONS:This study developed seven accident models and analyzed the common and specific variables by time of day and gender. The results suggest approaches to providing countermeasures for safer circular intersections.