• Journal of Korea Water Resources Association
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• v.51 no.11
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• pp.989-998
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• 2018

Connectivity between water source and demand node can be served as a critical system performance indicator of the degree of water distribution network (WDN)' failure severity under abnormal conditions. Graph theory-based approaches have been widely applied to quantify the connectivity due to WDN's graph-like topological feature. However, most previous studies used undirected-unweighted graph theory which is not proper to WDN. In this study, the directed-weighted graph theory was applied for WDN connectivity analyses. We also proposed novel connectivity indicators, Source-to-Node Shortest Pathway (SNSP) and SNSP-Degree (SNSP-D) which is an inverse of the SNSP value, that does not require complicate hydraulic simulation of a WDN of interest. The proposed SNSP-D index was demonstrated in total 42 networks in J City, South Korea in which Pearson Correlation Coefficient (PCC) between the proposed SNSP-D and four other system performance indicators was computed: three resilience indexes and an energy efficiency metric. It was confirmed that a system representative value of the SNSP-D has strong correlation with all resilience and energy efficiency indexes (PCC = 0.87 on average). Especially, PCC was higher than 0.93 with modified resilience index (MRI) and energy efficiency indicator. In addition, a multiple linear regression analysis was performed to identify the system hydraulic characteristic factors that affect the correlation between SNSP-D and other system performance indicators. The proposed SNSP is expected to be served as a useful surrogate measure of resilience and/or energy efficiency indexes in practice.

• Journal of Families and Better Life
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• v.10 no.1 s.19
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• pp.53-74
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• 1992

The purpose of this study was to analyse the factors that influence marital conflicts and family life statisfaction, and to predict the future stage of establishment family and extending family, bsed on the theretical model by system approach. For this pourpose, 336 couples of urban households in Seoul were selected. The data were analysed through statistical methods such as, Frequency, percentile, T-test, F-test, ANOVA, Pearson's correlation analysis. The results were as follow : The Martial Conflict and family life satisfaction of surveyed couples were above middle level. It had significantly differences according to family life cycle, husband and wife's educationed levels, husband and wife's occupations, and family income. And Family life satisfaction had significantly differences according to marital conflict. The marital conflict is higher, life satisfaction is lower. In this study, it were appeared that the amount of marital conflict and life satisfaction had differences according to life cycle stages, husband and wife's educational level, husband and wife occupations, and family income, and so that the conflict of phsycho-social system was more affected on family life satisfaction that of managerial system. Such results were indicated that the birth of children was the critical family event affecting on family life satisfaction on and the marital conflict. But the conflict by family's given resources and situational differences also as an environment affection on the family system.

• Journal of the Korean Home Economics Association
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• v.37 no.3
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• pp.63-84
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• 1999

The purpose of this study was to explore how family type based on intra system dynamics explained housewives'objective and subjective family financial well-being. The data were collected by means of questionnaire distributed to a stratified sample of 662 housewives in Seoul who usually managers household finances. The questionnaire included family cohesion and adaptability scale, communication scale, financial management scale, and subjective family financial well-being scale. Frequency, percentile, mean, Х$^2$ Pearson’s correlation, one-way ANOVA, multiple regression were used to analyze the data. The study had resulted in five major findings: 1. Among four intra system dynamics elements were highly relationships 2. Families were categorized tv four types, named personal-oriented(N: 164), managerial-oriented(N=169), dynamics(N=154), and non-dynamic(N=134) family. 3. The four types of family were influenced tv age of housewives, duration of marriage, and job status of husbands. 4. The four types of family were significantly related with subjective family financial well-being. The personal-oriented family type was significantly related with objective family financial well-being. 5. The dynamic family type showed the highest effect of subjective family financial well-being. The personal-oriented family type showed the greatest effect of objective family financial well-being. The recommendation for future research and better ways to enhance level of intra system dynamics elements and family financial well-being.

• Journal of KIISE:Software and Applications
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• v.30 no.3_4
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• pp.316-325
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• 2003

A user preference prediction method using an exiting collaborative filtering technique has used the nearest-neighborhood method based on the user preference about items and has sought the user's similarity from the Pearson correlation coefficient. Therefore, it does not reflect any contents about items and also solve the problem of the sparsity. This study suggests the preference prediction system using the similarity weight granted Bayesian estimated value and the associative user clustering to complement problems of an exiting collaborative preference prediction method. This method suggested in this paper groups the user according to the Genre by using Association Rule Hypergraph Partitioning Algorithm and the new user is classified into one of these Genres by Naive Bayes classifier to slove the problem of sparsity in the collaborative filtering system. Besides, for get the similarity between users belonged to the classified genre and new users, this study allows the different estimated value to item which user vote through Naive Bayes learning. If the preference with estimated value is applied to the exiting Pearson correlation coefficient, it is able to promote the precision of the prediction by reducing the error of the prediction because of missing value. To estimate the performance of suggested method, the suggested method is compared with existing collaborative filtering techniques. As a result, the proposed method is efficient for improving the accuracy of prediction through solving problems of existing collaborative filtering techniques.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.2
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• pp.174-188
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• 2004

In the life environment changed with not only the quality and the price of the products but also the material abundance, it is the most crucial factor for the strategy of product sales to investigate consumer's sensibility and preference degree. In this perspective, it is necessary to design and merchandise the products in cope with each consumer's sensibility and needs as well as its functional aspects. In this paper, we propose the Fashion Design Recommender Agent System (FDRAS-pro) for textile design applying collaborative filtering personalization technique as one of the methods of material development centered on consumer's sensibility and preference. For a collaborative filtering system based on textile, Representative-Attribute Neighborhood is adopted to determine the number or neighbors that will be used for preferences estimation. Pearson's Correlation Coefficient is used to calculate similarity weights among users. We build a database founded on the sensibility adjectives to develop textile designs by extracting the representative sensibility adjectives from users' sensibility and preferences about textile designs. FDRAS-pro recommends textile designs to a customer who has a similar propensity about textile. To investigate the sensibility and emotion according to the effect of design factors, fertile designs were analyzed in terms of 9 design factors, such as, motif source, motif-background ratio, motif variation, motif interpretation, motif arrangement, motif articulation, hue contrast, value contrast, chroma contrast. Finally, we plan to conduct empirical applications to verify the adequacy and the validity of our system.

• Journal of Korean Academy of Nursing Administration
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• v.20 no.4
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• pp.414-425
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• 2014

Purpose: The purpose of this study was to identify hospital nurses' recognition of the team system and the effectiveness of the team system as an organizational structure. Methods: A self-report questionnaire was used to collect data from 247 general hospital nurses during 4 months in 2013. Analysis was done using descriptive statistics, t-test, ANOVA, Pearson correlation coefficients and factor analysis with SPSS 18.0. program Results: There was no significant difference in nurses' recognition of team structure (t=2.06, p=.153) or effect of team structure (t=0.36, p=.549) according to use of team system. In hospitals with a team system, there were positive correlations between recognition of the effect of the team system and age (r=.25, p=.033), and total clinical career (r=.26, p=.012). In hospitals not using a team system, nurses' recognition of team structure as an organizational system (r=.31, p<.001), nurses' recognition of team structure, total (r=.30 p<.001) correlated significantly with the effects of team system. Conclusion: Results of this study provide a retrospection view of the team system in nursing organizational systems. The nursing team system's ultimate goal needs to be confirmed for complementary nursing care. Also, more studies on nurses' perceptions of, and effectiveness of the team system are necessary.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1102-1108
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• 2008

Wearable physiological signal monitoring systems are regarded as an important sensing unit platforms in ubiquitous/mobile healthcare application. In this paper, we suggested the modified bipolar electrodes implemented on the portable heart activity monitoring system, which minimized the distance of electrodes formed on a attachable pad. The proposed electrode configuration is useful in mobile measurement environments, but has a disadvantage of reduced amplitude of the heart action potential. In order to overcome the shortcoming of the suggested electrode configuration, we implemented the amplifying circuit to increase the signal-gain and decrease the artifacts. For evaluations, we analyzed the specificity of measured cardiography using the proposed electrodes through the comparing of heart activity monitoring system with standard clinical ECG(lead2) by pearson correlation coefficients. The result showed that the average correlation coefficient is $0.903{\pm}0.036,\;0.873{\pm}0.072$ at V3, V4 chest lead position, respectively. Thus, the modified bipolar electrode is quite suitable to monitor the electrical activity of the heart in the situation of the mobile environment, and could be considered having high similarity with standard clinical ECG.

• Journal of the Korean Society of Food Culture
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• v.12 no.1
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• pp.71-78
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• 1997

The productivity of a hospital foodservice system has a significant implication in hospital management as costs for labor and material increase, competitions among hospitals increase, and patients' expectations as to the quality of hospital services increase. The foodservice is characterized by its labor intensiveness. The objective of this study was to examine associations between operational and managerial factors and the productivity of dishwashing work in hospital foodservice systems. The labor productivity in 20 conventional food service systems was assessed and related to a number of influencing variables within the system. The productivity measurement was based upon the total dish equivalents as a ratio of the total direct and non-direct labor hours required to wash these dishes. 20 hospitals with more than 500 beds located in Seoul were surveyed to obtain data for study variables. Questionnaire and a survey form were mailed. Statistical methods used in this study were descriptive analysis and Pearson product moment correlation analysis. Hospital system characteristic which was found to correlate significantly with productivity was the ratio of dish loss. As this increased, the productivity level increased.

• Journal of the Korean Home Economics Association
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• v.37 no.2
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• pp.99-112
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• 1999

The purpose of this study were to investigate the effect of Family System Functioning, Parent & Child Factor and Parent-child Relation on Adolescent's Psychological Well-being (Family Life Satisfaction, Self-Esteem and Depression), and the causal relations of Adolescedent's Depression and Related Variables. The subjects were 532 triads of adolescents and their parents living in Seoul area, Korea. The survey methods were questionaires included FACES n, PAC Inventory, family life satisfactin scale, KMSS, Self-Esteem Inventory and CES-D, etc. Data were analyzed by frequencies, percentages, mean, standard deviation, paired t - test, Pearson's correlation , multiple regression, and path analysis The major findings were as follows: Family system functionings had a indirect effect through adolescents'family life satisfaction, self-esteem on adolescents'depression. The degree of openness of parent-adolescent communication and father's marital satisfaction had a indirect effect through adolescents'family life satisfaction on adolescents'depression. Adolescents'satisfaction with physical self, peer-relations and school life had a indirect effect through adolescents'self-esteem on their depression. Also adolescents'satisfaction with peer-relations and their fathers'depression had a direct effect on their depression.

• Korean Journal of Child Studies
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• v.31 no.4
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• pp.139-157
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• 2010

This study investigated the cognitive process of 5-year-old children, with a particular focus on gender, monthly age, and their tendencies towards hyperactivity through the performance of the Cognitive Assessment System (CAS; Das & Naglieri, 1997). The children with tendencies towards hyperactivity were identified based on Conners Teachers' Rating Scale (CTRS). The subjects were 75 five-year-old children in Seoul and surrounding metropolitan areas. Data were analyzed by means of descriptive statistics, an independent sample t-test, Pearson's correlation coefficient, one-way ANOVA, and by K-mean cluster analysis. Our results were as follows : (1) The CAS and CTRS' sub-factors were correlated negatively, except the positive correlation between planning factor and hyperactivity factor. (2) Girls exhibited significantly higher CAS scores in planning & sequential processing than boys. (3) The upper monthly age group (68-71 months) showed significantly higher score in terms of planning than the lower monthly age group (60-63 months). (4) The CAS scores of the children with tendencies towards hyperactivity was lower than that of normal children. (5) The CAS profile of 5-year-old children was divided into 4 groups with distinctive characteristics by means of K-mean cluster analysis.