• Korean Journal of Psychosomatic Medicine
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• v.24 no.1
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• pp.74-82
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• 2016

Objectives : Suicide attempters have impaired decision making and are at high risk of reattempt. Therefore it is important to refer them to psychiatric treatment. Especially, People with medical comorbidity are at higher risk of suicidal attempt and mortality. The aim of this study was to investigate the characteristics of suicidal attempters and to analyze the influence of the medical comorbidity on decision to receive psychiatric treatment after visit to an emergency department. Methods : One hundred and thirty two patients, who visited the emergency room of a general hospital in Gyeonggi-do between January, 2012 and December, 2012 were enrolled as the subjects of this study. After reviewing each subject's medical records retrospectively, demographic and clinical factors were analyzed. Results : Regardless of the engagement type, either via admission or outpatient clinic, the determinant factors of psychiatric treatment engagement were psychiatric diagnosis, employment status, previous psychiatric treatment history, and previous attempt history. Comparison of severity of medical comorbidity(Charlson Comorbidity Index) showed that suicide attempters who received psychiatric treatment via admission or refused the treatment tended to have higher level of medical comorbidity than who received psychiatric treatment via outpatient department. Conclusions : Our findings showed that medical comorbidity of suicide attempters affected the decision to accept psychiatric treatment. All psychiatrists should evaluate the presence and the severity of medical comorbidity of the suicide attempters and consider implementing more intervention for the medically ill attempters who are willing to discharge against advice.

• Journal of Intelligence and Information Systems
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• v.23 no.4
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• pp.77-110
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• 2017

Recently, the diversification and individualization of consumption patterns through the web and mobile devices based on the Internet have been rapid. As this happens, the efficient operation of the offline store, which is a traditional distribution channel, has become more important. In order to raise both the sales and profits of stores, stores need to supply and sell the most attractive products to consumers in a timely manner. However, there is a lack of research on which SKUs, out of many products, can increase sales probability and reduce inventory costs. In particular, if a company sells products through multiple in-store stores across multiple locations, it would be helpful to increase sales and profitability of stores if SKUs appealing to customers are recommended. In this study, the recommender system (recommender system such as collaborative filtering and hybrid filtering), which has been used for personalization recommendation, is suggested by SKU recommendation method of a store unit of a distribution company that handles a homogeneous brand through a plurality of sales stores by country and region. We calculated the similarity of each store by using the purchase data of each store's handling items, filtering the collaboration according to the sales history of each store by each SKU, and finally recommending the individual SKU to the store. In addition, the store is classified into four clusters through PCA (Principal Component Analysis) and cluster analysis (Clustering) using the store profile data. The recommendation system is implemented by the hybrid filtering method that applies the collaborative filtering in each cluster and measured the performance of both methods based on actual sales data. Most of the existing recommendation systems have been studied by recommending items such as movies and music to the users. In practice, industrial applications have also become popular. In the meantime, there has been little research on recommending SKUs for each store by applying these recommendation systems, which have been mainly dealt with in the field of personalization services, to the store units of distributors handling similar brands. If the recommendation method of the existing recommendation methodology was 'the individual field', this study expanded the scope of the store beyond the individual domain through a plurality of sales stores by country and region and dealt with the store unit of the distribution company handling the same brand SKU while suggesting a recommendation method. In addition, if the existing recommendation system is limited to online, it is recommended to apply the data mining technique to develop an algorithm suitable for expanding to the store area rather than expanding the utilization range offline and analyzing based on the existing individual. The significance of the results of this study is that the personalization recommendation algorithm is applied to a plurality of sales outlets handling the same brand. A meaningful result is derived and a concrete methodology that can be constructed and used as a system for actual companies is proposed. It is also meaningful that this is the first attempt to expand the research area of the academic field related to the existing recommendation system, which was focused on the personalization domain, to a sales store of a company handling the same brand. From 05 to 03 in 2014, the number of stores' sales volume of the top 100 SKUs are limited to 52 SKUs by collaborative filtering and the hybrid filtering method SKU recommended. We compared the performance of the two recommendation methods by totaling the sales results. The reason for comparing the two recommendation methods is that the recommendation method of this study is defined as the reference model in which offline collaborative filtering is applied to demonstrate higher performance than the existing recommendation method. The results of this model are compared with the Hybrid filtering method, which is a model that reflects the characteristics of the offline store view. The proposed method showed a higher performance than the existing recommendation method. The proposed method was proved by using actual sales data of large Korean apparel companies. In this study, we propose a method to extend the recommendation system of the individual level to the group level and to efficiently approach it. In addition to the theoretical framework, which is of great value.

• Radiation Oncology Journal
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• v.25 no.1
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• pp.43-53
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• 2007

[ $\underline{Purpose}$ ]: To evaluate the relationship between the expression of EGFR, p53, Cox-2, Bcl-2 and the clinical parameters of NPC (nasopharyngeal carcinoma) patients treated with radiotherapy with/without chemotherapy, and to determine if these could be used as a biologic marker. $\underline{Materials\;and\;Methods}$: This study retrospectively examined 75 NPC patients who were pathologically diagnosed at St. Mary's Hospital and Kangnam St Mary's Hospital from March 1988 to August 2002 and treated with radiotherapy with/without chemotherapy. The levels of EGFR, p53, Cox-2, and Bcl-2 expression were determined immunohistochemically. The relationship between the levels of EGFR, p53, Cox-2 and Bcl-2 expression and the H- E staining findings including the WHO classification, TNM stage, tumor response to chemotherapy and radiotherapy, disease free survival (DFS), and overall survival (OS) was analyzed. $\underline{Results}$: At a median follow up of 50.8 months (range: $5.5{\sim}201$ months), the 3 years OS rate and PFS rate were 68.7% and 68.2%, respectively. The five year OS rate and PFS rate were 53.5% and 51.1%, respectively. The median OS duration and PFS duration were 85.5 months and 61.1 months, respectively. The WHO classification correlated with the complete response rate, lymph node metastasis and distant metastasis. The expression of p53 was associated with increased mitosis and poor overall survival. The expression of Bcl-2 correlated with the DFS and WHO classification. The expression of Cox-2 correlated with a poor overall survival and response rate in the lymph node. However, EGFR was not correlated with any factors. $\underline{Conclusion}$: These results suggest that the expression of p53, Cox-2, Bcl-2 plays role in predicting prognostic factors for NPC treated with radiotherapy with/without chemotherapy. However, further study on a larger number of patients will be needed to identify more useful biomarkers of NPC.

• Clinical and Experimental Pediatrics
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• v.52 no.8
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• pp.917-921
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• 2009

Purpose : Although renal ultrasonography (USG) has improved the detection rate of hydronephrosis (HN), its clinical courses and postnatal management remains controversial. Here, we reviewed the clinical features of patients with HN according to the grades. Methods : We retrospectively studied 207 patients who were regularly followed-up among 367 patients with HN detected by renal USG postnatally between April 1998 and December 2007. These patients were grouped into four groups, grades 1-4, according to renal pelvic diameter (RPD). For analysis, each group was merged into two categories (mild: grade 1, 2; severe: grade 3, 4). Results : During follow-up, 128 episodes of urinary tract infection (UTI) occurred in 91 patients. According to grades from 1 to 4, 35/89 (39.3%), 41/88 (46.5%), 11/22 (50%), and 4/8 (50%), respectively, had UTI, without any significance between the mild and severe groups. However, the severe group presented a higher risk in cumulative episodes of UTI per year (P=0.041). The spontaneous resolution of HN was observed in 103 (58.8%) of the 175 mild group patients and in 3 (10.7%) of the 28 severe group patients (P<0.001). Furthermore, the detection rate of prenatal HN by prenatal USG was much higher in patients with severe RPD (P<0.001). Conclusion : We found that the severer the grade of HN, the lower was the rate of spontaneous resolution and higher was the frequency of UTI. Therefore, the establishment of guidelines for managing treatments such as antibiotic prophylaxis for patients with HN is needed to improve renal prognosis.

• Korean Journal of Psychosomatic Medicine
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• v.25 no.2
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• pp.200-209
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• 2017

Objectives : The aim of this study was to analyze the relationship between depressive symptoms and sociodemographic factors associated with geriatric depression and insomnia and to examine the effects of these factors on depression. Methods : The severities of insomnia and depression in elderly aged 60 and older lived in Gwangmyeong city were evaluated and the related sociodemographic factors were investigated. From April 20, 2016 to December 1, 2016, Gwangmyeong city Mental Health Sevices consignment by department of psychiatry of a university-affiliated general hospital conducted surveys and interviews for total 837 elderly peoples lived in Gwangmyeong city by visiting welfare center and wards located in the city. Structured interviews were conducted using Insomnia Severity Index(ISI) and Short form-Geriatric Depression Scale(S-GDS) to examine the relationship between sociodemographic factors and the severities of insomnia and depression. Results : There were significant differences in S-GDS mean scores and age(below 70 years old, 70s, 80s, above 90 years old), type of health care(health insurance, medical aid), type of residency(own, not own) and marital status(single, married, divorced or widowed).There was a significant difference in education level, especially between not educated(and/or) elementary graduates and college graduate(F=3.227, p=0.012). Also, there were significant differences in age, type of health care, type of residency, number of household on divided S-GDS score above and below 10 scores(p<0.05). Insomnia measured by ISI was not significantly associated with sociodemographic factors(p>0.05), but was significantly associated with depressive symptoms(p<0.05). These findings suggest more severe insomnia symptom indicated the higher probability of depression and elderly with depressive symptoms had more severe insomnia. Conclusions : Geriatric depression has significant relationships with age, type of health care, type of residency, marital status, education and number of households. In addition, insomnia which is main symptom of depression in elderly, has important role in predicting the severity and diagnosis of depression.

• Childhood Kidney Diseases
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• v.2 no.2
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• pp.145-151
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• 1998

Purpose : DMSA renal scan is known as a valuable method for evaluating acute pyelonephritis and renal scar in patients with febrile urinary tract infection or vesicoureteral reflux. We made this study, to determine the most effective use of DMSA renal scan. Methods : 155 children were admitted to the Pediatric Department of Yonsei University, Severance hospital with the symptom of urinary tract infection from January, 1992 to June, 1995. DMSA scan, renal ultrasound and VCUG were performed. One consisted of 29 patients with the diagnosis of acute pyelonephritis without vesicoureteral reflux and the otherconsistedofllpatientswithvesicoureteralreflux. Results : The follow-up DMSA scans at mean $0.99{\pm}0.46$ months after the initial DMSA scans were performed in the 29 children with acute pyetonephritis. 21($72.4\%$) of 29 children showed normal DMSA scans. 8 children with abnormal DMSA scans had follow-up DMSA scans at 2.5 months after the initial scans and 6 of 8 children showed normal DMSA scans. Only 12($41.4\%$) of 29 children showed abnormal renal ultrasound. The data about DMSA scans in 32 children with vesicoureteral reflux showed that there were abnormal DMSA scans in Grade $I;25.0\%$, Grade $II;44.5\%$, Grade $III;64.3\%$, Grade $IV;92.9\%$ and Grade $V;100.0\%$. There was a significant difference in that 36 renal unit ($68.0\%$) on DMSA renal scan and 26 renal units ($49.1\%$) on renal ultrasound showed abnormal finding(P<0.05). Conclusion : DMSA renal scan is more useful than renal ultrasound for the diagnosis of acute pyelonephritis. It is considered that if the initial DMSA scan is abnormal, a follow-up DMSA scan must be performed after 10weeks (8-12weeks) and the change in DMSA scan evaluated.

• Clinical and Experimental Pediatrics
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• v.46 no.10
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• pp.996-1002
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• 2003

Purpose : In Rett syndrome patients, the incidence of sudden death is greater than that of the general population, and cardiac electrical instability including fatal cardiac arrhythmia is a main suspected cause. In this study, we are going to find out the possible cause of the higher risk of sudden death in Rett patients by the evaluation of heart rate variability, a marker of cardiac autonomic activity and corrected QT intervals. Methods : Diagnosis of Rett syndrome was made by molecular genetic study of Rett syndrome (MECP2 gene) or clinical diagnostic criteria of Rett syndrome. Heart rate variability and corrected QT intervals were measured by 24 h-Holter study in 12 Rett patients, and in 30 age-matched healthy children with chief complaints of chest pain or suspected heart murmurs. The were compared with the normal age-matched control. Results : Patients with total Rett syndrome, classic Rett syndrome, and Rett variants had significantly lower heart rate variability(especially rMSSD)(P<0.05) and longer corrected QT intervals than age-matched healthy children(P<0.05). Sympathovagal balance expressed by the ratio of high to low frequency(LF/HF ratio) also showed statistically significant differences between the three groups considered(P<0.05). Conclusion : A significant reduction of heart rate variability, a marker of autonomic disarray, suggests a possible explanation of cardiac dysfunction in sudden death associated with Rett syndrome.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.261-267
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• 2007

Purpose: To evaluate the association between radiation pneumonitis and dose-volume histogram parameters and to provide practical guidelines to prevent radiation pneumonitis following radiotherapy administered for breast cancer including internal mammary lymph nodes. Materials and Methods: Twenty patients with early breast cancer who underwent a partial mastectomy were involved in this study. The entire breast, supraclavicular lymph nodes, and internal mammary lymph nodes were irradiated with a dose of 50.4 Gy in 28 fractions. Radiation pneumonitis was assessed by both radiological pulmonary change (RPC) and by evaluation of symptomatic radiation pneumonitis. Dose-volume histogram parameters were compared between patients with grade <2 RPC and those with grade ${\geq}$2 RPC. The parameters were the mean lung dose, V10 (percent lung volume receiving equal to and more than 10 Gy), V20, V30, V40, and normal tissue complication probability (NTCP). Results: Of the 20 patients, 9 (45%) developed grade 2 RPC and 11 (55%) did not develop RPC (grade 0). Only one patient developed grade 1 symptomatic radiation pneumonitis. Univariate analysis showed that among the dose-volume histogram parameters, NTCP was significantly different between the two RPC grade groups (p<0.05). Fisher's exact test indicated that an NTCP value of 45% was appropriate as an RPC threshold level. Conclusion: This study shows that NTCP can be used as a predictor of RPC after radiotherapy of the internal mammary lymph nodes in breast cancer. Clinically, it indicates that an RPC is likely to develop when the NTCP is greater than 45%.

• KDI Journal of Economic Policy
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• v.12 no.2
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• pp.51-79
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• 1990

Research on technical efficiency, an important dimension of market performance, had received little attention until recently by most industrial organization empiricists, the reason being that traditional microeconomic theory simply assumed away any form of inefficiency in production. Recently, however, an increasing number of research efforts have been conducted to answer questions such as: To what extent do technical ineffciencies exist in the production activities of firms and plants? What are the factors accounting for the level of inefficiency found and those explaining the interindustry difference in technical inefficiency? Are there any significant international differences in the levels of technical efficiency and, if so, how can we reconcile these results with the observed pattern of international trade, etc? As the first in a series of studies on the technical efficiency of Korea's manufacturing industries, this paper attempts to answer some of these questions. Since the estimation of technical efficiency requires the use of plant-level data for each of the five-digit KSIC industries available from the Census of Manufactures, one may consture the findings of this paper as empirical evidence of technical efficiency in Korea's manufacturing industries at the most disaggregated level. We start by clarifying the relationship among the various concepts of efficiency-allocative effciency, factor-price efficiency, technical efficiency, Leibenstein's X-efficiency, and scale efficiency. It then becomes clear that unless certain ceteris paribus assumptions are satisfied, our estimates of technical inefficiency are in fact related to factor price inefficiency as well. The empirical model employed is, what is called, a stochastic frontier production function which divides the stochastic term into two different components-one with a symmetric distribution for pure white noise and the other for technical inefficiency with an asymmetric distribution. A translog production function is assumed for the functional relationship between inputs and output, and was estimated by the corrected ordinary least squares method. The second and third sample moments of the regression residuals are then used to yield estimates of four different types of measures for technical (in) efficiency. The entire range of manufacturing industries can be divided into two groups, depending on whether or not the distribution of estimated regression residuals allows a successful estimation of technical efficiency. The regression equation employing value added as the dependent variable gives a greater number of "successful" industries than the one using gross output. The correlation among estimates of the different measures of efficiency appears to be high, while the estimates of efficiency based on different regression equations seem almost uncorrelated. Thus, in the subsequent analysis of the determinants of interindustry variations in technical efficiency, the choice of the regression equation in the previous stage will affect the outcome significantly.

• Pediatric Infection and Vaccine
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• v.16 no.1
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• pp.40-46
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• 2009

Purpose : The purpose of this study was to identify useful predictors for diagnosing bacterial meningitis and performing CSF studies in febrile infants three months or younger. Methods : Six hundred and fifty two febrile infants with a rectal temperature ${\geq}38.0^{\circ}C$ presented from January 2003 to April 2008 and were retrospectively studied. The total white blood cell count (WBC), band count, absolute neutrophil count (ANC), quantitative C-reactive protein (CRP) and blood cultures were performed on admission. The clinical variables associated with bacterial meningitis were analyzed. Results : In patients with bacterial meningitis, the clinical variables including CRP (P=0.036), band count (P=0.037), ANC (P=0.036) and age (P=0.001) were significantly different. The area under the receiver-operating characteristic curve was 0.969 for CRP, 0.946 for the band count, 0.765 for the ANC and 0.235 for age. A CRP cutoff point of 8 mg/dL was determined to maximize both the sensitivity and specificity (sensitivity 83%, specificity 95%, likelihood ratio 16.6). A CRP concentration of <7 mg/dL "ruled-out" bacterial meningitis, with a likelihood ratio of 0.17, a posttest probability of <0.1% and negative predictive value 91%. A CRP concentration greater than 9 mg/dL had a much higher likelihood ratio (20.1) than the band count (16.6) and ANC (2.2). Conclusion : The CRP concentration was a useful laboratory test for the differential diagnosis of bacterial meningitis among febrile infants three months of age or younger. A CRP concentration of <7 mg/dL effectively ruled out bacterial meningitis; a value ${\geq}9mg/dL$ increased the clinical suspicion of bacterial meningitis and the need for CSF evaluation.