• Journal of the Korea Society of Computer and Information
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• v.27 no.1
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• pp.83-89
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• 2022

As a representative technique of recommender systems, collaborative filtering has been successfully in service through many commercial and academic systems. This technique recommends items highly rated by similar neighbor users, based on similarity of ratings on common items rated by two users. Recently research on time-aware recommender systems has been conducted, which attempts to improve system performance by reflecting user rating time of items. However, the decay rate uniform to past ratings has a risk of lowering the rating prediction performance of the system. This study proposes a rating time-aware similarity measure between users, which is a novel approach different from previous ones. The proposed approach considers changes of similarity value over time, not item rating time. In order to evaluate performance of the proposed method, experiments using various parameter values and types of time change functions are conducted, resulting in improving prediction accuracy of existing traditional similarity measures significantly.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.398-398
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• 2022

최근 수돗물 공급과정에 있어 적수, 유충 발생 등 지역 단위의 수질문제로 국민의 직간접적인 피해가 발생된 바 있다. 수질문제 발생 시, 소셜네트워크서비스(SNS)에 게시되는 피해 관련 의견은 시공간적으로 빠르게 확산되며, 궁극적으로는 물공급과정 전체의 부정적 인식증가와 신뢰도 저하를 초래한다. 따라서, 물공급시스템에서의 수질사고 발생을 빠르게 인지하는 다양한 방법론의 적용을 통한 피해 최소화를 위한 노력이 반드시 필요하다. 일반적으로 수질사고는 다양한 항목의 실시간 계측기에서 획득되는 시계열자료의 변화양상을 통해 판단할 수 있으나, 이와 같은 방법론의 효율적 적용을 위해서는 선진계측인프라의 도입이 선행되어야 한다. 본 연구에서는 국내의 발달된 정보통신기술환경을 활용하여, 물공급네트워크 내 수질사고인지를 위한 SNS 별 웹크롤링 방법론을 제안하고, 적용결과를 분석하였다. 방법론의 구현에 앞서, 각종 SNS 별(트위터, 인스타그램, 블로그, 네이버 카페 등) 프로그래밍을 통한 웹크롤링 가능여부, 정보획득 기간 등을 확인하였으며, 과거 유사 수질사고 발생 시 영향력과 관련 게시글이 크게 나타난 네이버 카페와 트위터를 중심으로 웹 크롤링 절차를 제시하였다. 네이버 카페의 경우 대상급수구역 내의 시민들이 다수 참여하는 카페를 목록화하고, 지자체명과 핵심 키워드(수돗물, 유충, 적수) 조합을 활용한 웹크롤링을 수행하여, 관련 게시물 건수와 의미를 실시간으로 분석하는 절차를 마련하였다. 개발된 SNS 별 웹크롤링 방법론에 따라 과거 수질사고가 발생된 바 있는 2개 이상의 지자체에 대한 분석을 실시하였으며, SNS 별 결과에 있어 차이점을 확인하여 제시하였다. 향후 제안된 방법을 적용하여 시공간적 수질사고 정보의 전파 및 확산양상을 추가적으로 분석할수 있을 것으로 기대된다.

• The Journal of the Korea Contents Association
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• v.14 no.5
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• pp.190-198
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• 2014

The purpose of study was evaluated associations among risk factors to have influence on HRQOL of community dwelling Elderly People. Total 314 community dwelling elderly persons(age:$75.80{\pm}5.64$[$mean{\pm}SD$]) who had no disease(n=81) and more than two chronic diseases (n=233) were interviewed based on the QOL questionnaires. During two months. The activities of daily living were evaluated using BI and FAI. Neuropsychological status was evaluated using GDS. Health related QOL was evaluated using the SF-36. The results emphasize the importance of preventing and controlling depression, chronic diseases, and low basic activities of daily living in order to reduce their impact on HRQOL among community dwelling elderly people.

• International Commerce and Information Review
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• v.16 no.3
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• pp.3-23
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• 2014

This study focused on causes of use reluctant intention because closed SNS was more active than open SNS was despite tremendous growth of SNS to have negative influence upon not only SNS contents suppliers but also marketing business using SNS. The survey were conducted a total of 205 participants with adult over colleague student, 197 copies that excluded questionnaire with unfaithful answer were used in the analysis, and we used path analysis of structural equation modeling. The results of modified path model showed that interactivity was influenced by value, and then affecting "trust ${\rightarrow}$ satisfaction ${\rightarrow}$ using reluctant intention" path and "satisfaction ${\rightarrow}$ using reluctant intention" path. These result reflected that interactivity have a double-edged sword and value is very important standard to make a positive of negative role of interactivity. These results suggested that interactivity was found to have influence upon not only behavioral willingness that took actions depending upon either improvisation or situation but also behavioral intention path that thought and took actions in reasonable way. The interactivity had double-edged sword to help develop SNS and to produce negative results.

• Journal of Hospice and Palliative Care
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• v.17 no.3
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• pp.170-178
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• 2014

Purpose: Delirium is a common and serious neuropsychiatric complication among terminally ill cancer patients. We investigated risk factors related to the development of delirium among hospice care patients. Methods: Between May 2011 and September 2012, we included patients who were mentally alert and had no psychiatric disease or drug addiction at the hospice ward of two local hospitals. Among them, participants who had been diagnosed with delirium by two doctors according to the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders-4th edition) criteria were grouped as Delirium Group. We analyzed results of psychometric and other laboratory tests performed at the time of patient's admission - psychometric tests included cognitive function (mini-mental status examination, MMSE), depression (Beck Depression Inventory, BDI), anxiety, and insomnia (Insomnia Severity Index, ISI). Logistic regression analysis was used to compare delirium and the related factors. Cox's proportional hazard model was performed using significant factors of logistic regression analysis. Results: Of the 96 patients who met the inclusion criteria, 41 (42.7%) developed delirium. According to the logistic regression analysis, primary cancer site, cognitive impairment (MMSE < 24), depression ($BDI{\geq}16$), and insomnia ($ISI{\geq}15$) were significant factors related to delirium. Among the four factors, depression (OR 5.130; 95% CI, 2.009~13.097) and cognitive impairment (OR 5.130; 95% CI, 2.009~13.097) were found significant using Cox's proportional hazard model. Conclusion: The development of delirium was significantly related to depression and cognitive impairment among patients receiving hospice care. It is necessary to carefully monitor depression and cognitive function in hospice care.

• Korean Journal of Psychosomatic Medicine
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• v.27 no.1
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• pp.60-68
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• 2019

Objectives : The association between thyroid-related hormones and cognitive function has been controversial. The purpose of this study is to compare the levels of thyroid-related hormones in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). Furthermore, we investigated the relationship between thyroid-related hormones and cognitive function. Methods : From January 2011 to December 2018, we retrospectively reviewed 105 patients who were diagnosed with AD and MCI by visiting a dementia clinic at Ilsan Paik Hospital. Thyroid-related hormones [triiodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH)] was measured using chemiluminescent immunoassay. An independent sample t-test was performed to analyze the mean value of thyroid-related hormones in patients of AD and MCI. To investigate whether thyroid-related hormones correlate significantly with Global deterioration scale (GDS), Clinical dementia rating (CDR) and scores of each The Korean version of the consortium to establish a registry for Alzheimer's disease items, we conducted a partial correlation analysis with geriatric depression scale-Korean version (GDS-K) scores as covariates. Results : There was no significant difference in the mean serum T3, T4 and TSH levels between patients of the AD and the MCI, but the Construction Praxis Test (CPT) showed a significant positive correlation with the serum TSH concentration (p-value=0.004). Conclusions : In our study, the positive correlation between serum TSH level and the CPT associated with executive function was found to be helpful in understanding the association between thyroid-related hormones and the pathophysiology of dementia. Prospective studies in regard of the pathophysiology of thyroid-related hormones on cognitive function will be necessary in the future.

• Food Science and Preservation
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• v.17 no.5
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• pp.688-697
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• 2010

We investigated the cholesterol-lowering and body-weight loss effects of Cheonggukjang fermented using Bacillus subtilis DJI in rats fed a high-fat/high-cholesterol diet for 4 weeks. Weight-matched male Sprague-Dawley rats were assigned to one of four groups: a normal diet group (N), a high-fat/high-cholesterol diet group (HFC), a high-fat/high-cholesterol diet with DJI Cheonggukjang group (HFC-SCK), and a high-fat/high-cholesterol with commercial Cheonggukjang group (HFC-CCK). All of body weight and liver and adipose tissue weights increased in animals fed a high-fat/high-cholesterol diet, but decreased significantly in rats fed Cheonggukjang powder, compared with the HFC group. Food intake was lower in the HFC group than in the N group, and that of the HFC-CCK group was the lowest among the four groups. Serum total cholesterol levels were significantly lower in the Cheonggukjang-powder fed groups than the other groups. Serum phospholipid and HDL-cholesterol concentrations were significantly decreased in HFC animals and were markedly increased upon feeding of a Cheonggukjang-containing-diet. Levels of serum LDL-cholesterol, the atherogenic index, and cardiac risk factor assessment indications tended to be decreased in Cheonggukjang powder-fed groups, compared with the HFC group. The total cholesterol level in liver tissue was increased by feeding of a high-fat/high-cholesterol diet, and was significantly reduced when Cheonggukjang powder was present in the diet. The levels of total lipids and triglycerides in adipose tissues were lower in the HFC-SCK group than in the HFC group, whereas no significant differences were evidence when the HFC and the HFC-CCK groups were compared. Fecal weight, moisture level, and total lipid content increased in animals fed Cheonggukjang powder. The activities of HR-LPL and TE-LPL in adipose tissues were increased in the HFC group compared with the Cheonggukjang powder-fed groups. These results indicate that dietary Cheonggukjang may improve lipid metabolism and prevent obesity and hyperlipidemia.

• Korean Journal of Psychosomatic Medicine
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• v.20 no.2
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• pp.105-111
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• 2012

Objectives : We investigated the prevalence and composite score of the neuropsychiatric symptoms in patients with mild cognitive impairment(MCI), and dementia of Alzheimer's type(AD). The aim of this study is to analyze the correlation between the result of Korean Neuropsychiatric Inventory(K-NPI) and cognitive function. Methods : A total of 163 patients diagnosed with MCI or AD was divided into three groups(55 MCI patients, 56 dementia patients with mild stage, and 52 dementia patients with moderate, severe stage). We examined neuro-psychiatric symptoms by K-NPI and compared the prevalence and composite score of each subdomain in K-NPI among three groups. Results : The most common symptoms in the MCI group were depression/dysphoria, sleep/night-time behavior, anxiety, and irritability/lability. In mild AD group, the most frequent disturbance was agitation/aggression, depression/dysphoria, anxiety, apathy/indifference, and sleep/night-time behavior. In moderate to severe AD group, the most frequent disturbance was apathy/indifference, depression/dysphoria, agitation/aggression, and delusion. The frequencies of delusion, hallucination, agitation/aggression, apathy/indifference, aberrant motor behavior, appetite/eating change were statistically significant. The total NPI score showed a negative correlation with MMSE-KC and a positive correlation with GDS. Conclusions : Neuropsychiatric symptoms are common features of MCI and AD. These symptoms observed in MCI are similar to those of mild AD. Psychosis is most common in moderate to severe AD, leading to a faster rate of cognitive decline. Therefore, proper management according to the neuropsychiatric symptoms of MCI and three stages of dementia is needed.

• Korean Journal of Psychosomatic Medicine
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• v.22 no.2
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• pp.104-111
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• 2014

Objectives : The aim of this study was to investigate the relationship between metabolic syndrome and cognitive functions among chronic schizophrenia patients. Methods : The survey participants were 105(40 metabolic syndrome and 65 non-metabolic syndrome) chronic schizophrenia patients at Yang-san Hospital. Each score of cognitive test(A Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet, stroop test), Positive and Negative Syndrome Scale, Hamilton rating scale for Depression were assessed. Statistical analysis of the relationship between various tests of A Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet and metabolic syndrome were performed using ANCOVA and logistic regression. Results : Schizophrenia patients with lower score on construction praxia were likely to be included in Metabolic syndrome group. However, there were no significant relationships in other tests between the two groups. Conclusions : This study found metabolic syndrome caused cognitive decline in chronic schizophrenia patients, especially Construction praxia. This study could be a basis to show metabolic syndrome has to be treated appropriately in schizophrenia patients and suggests the necessity of following longitudinal designed study.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.6
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• pp.127-137
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• 2015

Recent research has shown that university students experience severe stress and depleted directed attention due to study, social relationships, and economic dependency. Based on the stress reduction theory and the attention restoration theory, this study aims to investigate the effects of natural landscape on university students' stress and cognitive performance through a wide array of measurements including GSR(galvanic skin responsse), IBI(interbeat interval), ZIPERS(Zucherman Inventory of Personal Reactions), and mental arithmetic test. The restorative effects of natural landscape were compared with those of urban landscape. 128 university students participated in the study, and the data of 120 students was analyzed. The results showed that natural landscape was more restorative in relieving psychological stress and in enhancing cognitive performance than urban landscape, which evidenced the restorative effects of natural landscape. Therefore, it could be proposed that natural landscaping of the university campus contributes to students' stress reduction and cognitive enhancement. But such effects were not found in the two physiological measures(both GSR and IBI). Moreover, it was analyzed that urban landscape had a more beneficial effect than natural landscape for IBI, which might resulted from the participants' characteristics and the study landscape. Specifically, the young age span of the participants(average 23.8 years old) and the very natural setting of the university where they were enrolled might lead to the conflicting results in physiological measures. Also, the urban landscape used in the study had a sense of "scope", which is one of the Kaplan and Kaplan's restorative characteristics. Based on this opinion, it was suggested that future study should investigate the impact of the landscape type and contents as well as the participants' characteristics on the restorative effects of natural landscape.