• Journal of the Korea Society of Computer and Information
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• v.27 no.9
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• pp.59-68
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• 2022

A recommender system covers users, searches the items or services which users will like, and let users purchase them. Because recommendations from a recommender system are predictions of users' preferences for the items which they do not purchase yet, it is rarely possible to be drawn a perfect answer. An evaluation has been conducted to determine whether a prediction is right or not. However, it can be lower user's satisfaction if a recommender system focuses on only the preferences, that is caused by a 'filter bubble effect'. The filter bubble effect is an algorithmic bias that skews or limits the information an individual user sees on the recommended list. It is the reason why multiple metrics are required to evaluate recommender systems, and a diversity metrics is mainly used for it. In this paper, we compare three different methods for enhancing diversity for personalized recommendation - bin packing, weighted random choice, greedy re-ranking - with a practical e-commerce data acquired from a fashion shopping mall. Besides, we present the difference between experimental results and F1 scores.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.3
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• pp.49-56
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• 2022

ROK Navy intends to secure the Korean-type aircraft carrier in order to effectively prepare for various future security threats. In general, the Korean national competency is considered to be at the level of having an aircraft carrier, but it is unclear what scale aircraft carrier would be appropriate. In this study, the efficiency was evaluated through the relative comparison between national competency(national power, economic power) and the scale of aircraft carriers, and the optimal scale of the Korean-type aircraft carrier that could be acquired was presented. A DEA(Data Envelopment Analysis) model was applied to aircraft carriers(19 aircraft carriers in 11 countries) currently in operation and scheduled to be possessed in the world. As input variables, CINC(Composite Index of National Capability) and GDP(Gross Domestic Product), which are the most widely used as indicators of national and economic power, and as output variables, the full-load displacement, length, and width of aircraft carriers were selected. ARIMA(short-term within 5 years) and simple regression(long-term over 5 years) were used to estimate the future national competency of each country at the time of aircraft carriers acquisition. The relative efficiency score of the Korean-type aircraft carrier currently being evaluated is 1.062, and it was evaluated as small-scale aircraft carrier compared to the national competency. Based on Korean national competency, the optimal scale of the Korean-type aircraft carrier calculated by aggregating benchmark groups, is 58,308.1 tons of full-load displacement, 279.4m in length, and 68.3m in width.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.1135-1141
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• 2023

The purpose of this study was to investigate the effect of Grit and Self-elasticity on Carrer Identity of nursing students. Data were collected among 193 nursing students in G city, from Sep 4 to 15 2023. The collected data was analyzed a using t-test, One way ANOVA, Pearson correlation coefficient and Stepwise multiple regression using SPSS 20.0 WIN program. The results revealed that the average score for Self-elasticity was 3.42±0.45, Grit was 3.63±0.60, Carrer Identity was 4.06±0.79. students acquired Self-elasticity by gender as per general characteristics. The Carrer Identity showed statistically significant differences in gender. There was a statistically significant positive correlation between the Carrer Identity of Self-elasticity(r=.370, p=.000), and Grit(r=.283, p=.000). Carrer Identity showed Models including the variables, Self-elasticity, Gender, Grit explained 22.6% of the variance in the Carrer Identity stress. Based on the outcome of this study, steps should be taken to design intervention program that emphasize a improve Carrer Identity for nursing students.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.122-127
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• 2010

Purpose: The Xpress3.$cardiac^{TM}$ which is a kind of wide beam reconstruction (WBR) method developed by UltraSPECT (Haifa, Israel) enables the acquisition of at quarter time while maintaining image quality. The purpose of this study is to investigate the usefulness of WBR method for decreasing scan times and to compare to it with filtered back projection (FBP), which is the method routinely used. Materials and Methods: Phantom and clinical studies were performed. The anthropomorphic torso phantom was made on an equality with counts from patient's body. The Tl-201 concentrations in the compartments were 74 kBq (2 ${\mu}Ci$)/cc in myocardium, 11.1 kBq (0.3 ${\mu}Ci$)/cc in soft tissue, and 2.59 kBq (0.07 ${\mu}Ci$)/cc in lung. The non-gated Tl-201 myocardial perfusion SPECT data were acquired with the phantom. The former study was scanned for 50 seconds per frame with FBP method, and the latter study was acquired for 13 seconds per frame with WBR method. Using the Xeleris ver. 2.0551, full width at half maximum (FWHM) and average image contrast were compared. In clinical studies, we analyzed the 30 patients who were examined by Tl-201 gated myocardial perfusion SPECT in department of nuclear medicine at Asan Medical Center from January to April 2010. The patients were imaged at full time (50 second per frame) with FBP algorithm and again quarter-time (13 second per frame) with the WBR algorithm. Using the 4D MSPECT (4DM), Quantitative Perfusion SPECT (QPS), and Quantitative Gated SPECT (QGS) software, the summed stress score (SSS), summed rest score (SRS), summed difference score, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were analyzed for their correlations and statistical comparison by paired t-test. Results: As a result of the phantom study, the WBR method improved FWHM more than about 30% compared with FBP method (WBR data 5.47 mm, FBP data 7.07 mm). And the WBR method's average image contrast was also higher than FBP method's. However, in result of quantitative indices, SSS, SDS, SRS, EDV, ESV, EF, there were statistically significant differences from WBR and FBP(p<0.01). In the correlation of SSS, SDS, SRS, there were significant differences for WBR and FBP (0.18, 0.34, 0.08). But EDV, ESV, EF showed good correlation with WBR and FBP (0.88, 0.89, 0.71). Conclusion: From phantom study results, we confirmed that the WBR method reduces an acquisition time while improving an image quality compared with FBP method. However, we should consider significant differences in quantitative indices. And it needs to take an evaluation test to apply clinical study to find a cause of differences out between phantom and clinical results.

• Ecology and Resilient Infrastructure
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• v.8 no.4
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• pp.253-265
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• 2021

In this study, crop cultivation filed was extracted by using Unmanned Aerial Vehicle (UAV) imagery and deep learning models to overcome the limitations of satellite imagery and to contribute to the technological development of understanding the status of crop cultivation field. The study area was set around Chungbuk Goesan-gun Gammul-myeon Yidam-li and orthogonal images of the area were acquired by using UAV images. In addition, study data for deep learning models was collected by using Farm Map that modified by fieldwork. The Attention U-Net was used as a deep learning model to extract feature of UAV in this study. After the model learning process, the performance evaluation of the model for corn cultivation extraction was performed using non-learning data. We present the model's performance using precision, recall, and F1-score; the metrics show 0.94, 0.96, and 0.92, respectively. This study proved that the method is an effective methodology of extracting corn cultivation field, also presented the potential applicability for other crops.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.23 no.1
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• pp.23-30
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• 2012

Objectives : This study was conducted to investigate the prevalence of victims of bullying and the demographic characteristics of victims, and their related psychopathology, in a Korean nationwide sample of youths in middle and high school over a one month period. Methods : During the autumn of 2009, students in the 7th to 12th grades at 23 secondary schools participated in a nationwide, cross-sectional study. The study subjects completed the Adolescent Mental Health and Problem Behavior Screening Questionnaire-II (AMPQ-II) and Symptom Checklist-90-Revision (SCL-90-R). Based on the data acquired, descriptive statistics, correlation coefficients and multiple logistic regression analysis were performed. Results : Among the 3364 participants, 2272 (67.54%) completed the questionnaire. The prevalence of victimization was 28.9%. Male gender was positively associated with victimization, and grade level was negatively related to victimization. The AMPQ-II bullying score (Factor 4) was significantly (p<.001) and positively correlated to the AMPQ-II student total score (r= 0.50), Worry and thought (Factor 1 ; r=0.38), Mood and suicide (Factor 2 ; r=0.31), Academic and Internet-related problems (Factor 3 ; r=0.24), Rule violations (Factor 5 ; r=0.23), and AMPQ-II teacher total score (r=0.11). Somatization (r=0.23), Obsessive-compulsive behavior (r=0.24), Interpersonal sensitivity (r=0.30), Depression (r=0.33), Anxiety (r=0.26), Hostility (r=0.30), Phobic anxiety (r=0.22), Paranoid ideation (r=0.36), and Psychoticism (r=0.31) results from the SCL-90-R were also found to be positively related to the AMPQ-II bullying score, and remained significant after adjusting for age and gender. A total of 26% of the victims reported suicidal ideations as compared to 9% of non-victims over the month prior to the evaluation ($x^2$=119.595, df=1, p<.001). The multiple logistic regression analysis indicated that the AMPQ-II bullying score significantly increased the risk of suicidal ideation [Exp(b)=1.55, df=1, p<.001] after adjusting for age and gender. Conclusion : School bullying was highly prevalent among Korean middle and high school students. This study provided strong evidence that suicidal ideation and psychopathology were serious problems among the victims of bullying.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1234-1240
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• 2009

This study was to compare the effectiveness and validity of various data-mining algorithm for Sasang type diagnostic test. We compared the sensitivity and specificity index of nine attribute selection and eleven class classification algorithms with 31 data-set characterizing Sasang typology and 10-fold validation methods installed in Waikato Environment Knowledge Analysis (WEKA). The highest classification validity score can be acquired as follows; 69.9 as Percentage Correctly Predicted index with Naive Bayes Classifier, 80 as sensitivity index with LWL/Tae-Eum type, 93.5 as specificity index with Naive Bayes Classifier/So-Eum type. The classification algorithm with highest PCP index of 69.62 after attribute selection was Naive Bayes Classifier. In this study we can find that the best-fit algorithm for traditional medicine is case sensitive and that characteristics of clinical circumstances, and data-mining algorithms and study purpose should be considered to get the highest validity even with the well defined data sets. It is also confirmed that we can't find one-fits-all algorithm and there should be many studies with trials and errors. This study will serve as a pivotal foundation for the development of medical instruments for Pattern Identification and Sasang type diagnosis on the basis of traditional Korean Medicine.

• Journal of Korean Academy of Nursing Administration
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• v.9 no.4
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• pp.529-539
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• 2003

Purpose : The objective of this research is to explore the job satisfaction of clinical nurses by the rank of nurse staffing in order to provide effective management for nurses. Method : The research has been conducted on three hundred twenty nurses working at tertiary eight hospitals which were from 2nd rank of nurse staffing to 5th. rank of nurse staffing in Seoul, from August 1 to September 30 of 2003, through survey. For the experimental tools, used Park-Yoon's job satisfaction for nurses(1992) which was modified Stamp's job satisfaction test(1978). The acquired data were analyzed through SPSS program using descriptive method, $x^2$-test, ANCOVA, and LSD. Results : Overall job satisfaction of nurses showed fairly high level of 3.17; in the order of high score, 3.84 for interaction, 3.00 for autonomy, 2.63 for administration. Analysis based of the rank of nurse staffing showed that hospitals of 2nd rank and 3rd. rank of nurse staffing which were higher ratio of patient vs nurse were more satisfied with nurses' job satisfaction than other nurses who were 4th. rank and 5th. rank of nurse staffing. Conclusion : The result of this study revealed that hospital which was higher the rank of nurse staffing was more influenced of nurses' job satisfaction and especially interaction, administration and autonomy which were sub-category of job satisfaction were different among the ranks of nurse staffing.

• Journal of Digital Convergence
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• v.16 no.4
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• pp.277-288
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• 2018

This study investigated the correlations of the AIDS knowledge, self-esteem, sense of control, optimistic bias toward AIDS, and condom use in the Chinese male college students. A cross-sectional survey was used, and 307 male students were recruited from anonymous universities in cities of two provinces in China. The data were analyzed according to descriptive statistics, ANOVA, Pearson's correlations. The Chinese male college students had an optimistic bias toward AIDS. The score of AIDS knowledge was 73%, and the self-esteem and sense of control scores were all rated higher than the median. The difference among groups according to grade and age were statistically significant in this study. The self-esteem, sense of control, and optimistic bias toward AIDS showed significant positive correlations, but AIDS knowledge, optimistic bias, and condom use have no correlations. The studies that examine psychological variables with condom use among various groups should be followed in the Chinese context.

• The Journal of Korean Physical Therapy
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• v.24 no.2
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• pp.98-106
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• 2012

Purpose: The goal of this study was to analyze the degree of stress and methods of coping with stress in mothers of cerebral palsied children and to provide a basic resource for the development of policies to improve the mental health of mothers with cerebral palsied children. Methods: 85 mothers with cerebral palsied children and 77 mothers of normal children completed a self-administered questionnaire that evaluated the degree of stress and methods of coping with stress. Cronbach's ${\alpha}$ score was used to determine the internal consistency of the acquired data and the discriminated validity was estimated by Pearson's correlation coefficient. Independent t-tests were conducted to compare the degree of stress and method of coping with stress between mothers of cerebral palsied children and mothers of normal children and one-way ANOVA was performed to analyze the effect of generalized characteristics on stress in mothers of cerebral palsied children. Results: The degree of stress in terms of anxiety response and roles as mother for mothers with cerebral palsied children was higher than mothers with normal children. However, there was no significant difference between two group in regards to the methods of coping with stress during a stressful episode. The degree of stress for mothers with cerebral palsied children was greater when the child was younger. Conclusion: Mothers of cerebral palsied children had higher stress than that of mothers with normal children and felt more stress when their child was younger. Therefore, these results suggest that health-based policies should be developed to improve the mental health of mothers with cerebral palsied children.