• Journal of Intelligence and Information Systems
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• v.20 no.4
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• pp.107-120
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• 2014

This study proposes a novel recommender system using the structural hole analysis to reflect qualitative and emotional information in recommendation process. Although collaborative filtering (CF) is known as the most popular recommendation algorithm, it has some limitations including scalability and sparsity problems. The scalability problem arises when the volume of users and items become quite large. It means that CF cannot scale up due to large computation time for finding neighbors from the user-item matrix as the number of users and items increases in real-world e-commerce sites. Sparsity is a common problem of most recommender systems due to the fact that users generally evaluate only a small portion of the whole items. In addition, the cold-start problem is the special case of the sparsity problem when users or items newly added to the system with no ratings at all. When the user's preference evaluation data is sparse, two users or items are unlikely to have common ratings, and finally, CF will predict ratings using a very limited number of similar users. Moreover, it may produces biased recommendations because similarity weights may be estimated using only a small portion of rating data. In this study, we suggest a novel limitation of the conventional CF. The limitation is that CF does not consider qualitative and emotional information about users in the recommendation process because it only utilizes user's preference scores of the user-item matrix. To address this novel limitation, this study proposes cluster-indexing CF model with the structural hole analysis for recommendations. In general, the structural hole means a location which connects two separate actors without any redundant connections in the network. The actor who occupies the structural hole can easily access to non-redundant, various and fresh information. Therefore, the actor who occupies the structural hole may be a important person in the focal network and he or she may be the representative person in the focal subgroup in the network. Thus, his or her characteristics may represent the general characteristics of the users in the focal subgroup. In this sense, we can distinguish friends and strangers of the focal user utilizing the structural hole analysis. This study uses the structural hole analysis to select structural holes in subgroups as an initial seeds for a cluster analysis. First, we gather data about users' preference ratings for items and their social network information. For gathering research data, we develop a data collection system. Then, we perform structural hole analysis and find structural holes of social network. Next, we use these structural holes as cluster centroids for the clustering algorithm. Finally, this study makes recommendations using CF within user's cluster, and compare the recommendation performances of comparative models. For implementing experiments of the proposed model, we composite the experimental results from two experiments. The first experiment is the structural hole analysis. For the first one, this study employs a software package for the analysis of social network data - UCINET version 6. The second one is for performing modified clustering, and CF using the result of the cluster analysis. We develop an experimental system using VBA (Visual Basic for Application) of Microsoft Excel 2007 for the second one. This study designs to analyzing clustering based on a novel similarity measure - Pearson correlation between user preference rating vectors for the modified clustering experiment. In addition, this study uses 'all-but-one' approach for the CF experiment. In order to validate the effectiveness of our proposed model, we apply three comparative types of CF models to the same dataset. The experimental results show that the proposed model outperforms the other comparative models. In especial, the proposed model significantly performs better than two comparative modes with the cluster analysis from the statistical significance test. However, the difference between the proposed model and the naive model does not have statistical significance.

• Journal of the Korean Wood Science and Technology
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• v.48 no.2
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• pp.206-216
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• 2020

This study was conducted to analyze the sap flow and composition by tapping date in Acer akamotoanum from an artificial forest in the City of Jinju. The sap was collected from five saplings (diameter at breast height10-20 cm) in two phases with an interval of a month. During phase 1 (January 10, 2019 - February 9, 2019) with daily mean temperature of 1.16±2.15℃, 60.59 liters of sap was collected over 32 days. Phase 2 (February 12, 2019 - February 22, 2019) with daily mean temperature of 2.55±1.30℃ yielded 13.38 liters of sap over 11 days, which was a reduction to 22% of the total sap flow in phase 1. The analysis of sugar composition in the collected sap from phase 1 and 2 showed that sucrose concentration was 2.5% at its highest during the earlier days of collection and decreased to 0.8% at the end. Glucose and fructose concentrations were measured near 0, and were lower than sucrose concentration. The most prominent inorganic elements in the collected sap were potassium (41.69 - 89.75 mg/kg), calcium (24.66 - 48.14 mg/kg) and magnesium (10.18 - 27.25 mg/kg). The contents of sucrose and inorganic components between the samples collected from phase 1 and 2 did not show significant differences. The sap flow amounts of A. okamotoanum from different tapping periods showed a notable variation, but there were no significant differences in the contents of sugar or inorganic elements.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.2
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• pp.2262-2275
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• 1971

Fourteenes rervoirs maintained by the local land improvement associations in the province of Chullabuk-Do and 20 reservoir maintained by thos in the province of Chullanam-Do, were surveyed in connection with a correction between storage capacity and sediment deposit. In addition to this survey, 3,347 of small reservoir, that lie scattered around in the above-mentioned two provinces were investigated by using existing two provinces were investigated by using existing records pertaining to storage capacity in the office of City and country, respectively. According to this investigation the following comclusions are derived. 1. A sediment deposition rate is high, being about $10.63m^3/ha$ of drainage area, and resulting in the average decreasc of storage capaity by 27.5%. This high rate of deposition coule be mainly attributed to the serve denudation of forests due to disorderly cuttings of trees. Easpecially, in small reservoir, an original average design storage depth of 197mm in irrigation water depth is decreased to about 140mm. 2. An average unit storage depth of 325.6mm as the time of initial construction is decreased to 226mm at present. This phenomena causes a greater shortage irrigation water, since it was assumed that original storage quantity was already in short. 3. Generally speaking, seepage rates through dam abutment intakepipe, etc, are high due to insufficient maintenance and management of reservoir. 4. It is recommended that sediment deposit should be dredged when a reservoir is dry in drought. 5. Farmers usually waste excessive irrigation water. 6. Water saving methods should be practiced by applying only necessary water for growing stage of rice. 7. In are as where water defficiency for irrigation is severe, a soil moisture content should be kept at about 70% by applying water once in several days. 8. Tube wells should be provided so as to exploit ground water and subsurface current below stream bed as much as possible. 9. If an intake weir was constructed, a water collection well should be built for the use in drought. 10. Water conservation should be forced by converting devastated forests contained in the drainage area of reservoir to protected forests so as to take priority of yrefor estation, gully control, the prohibition of disorderly cutting of trees, etc. 11. Collective rice nurseries should be adopted, and it should be recommended that irrigation water for rice nurseries is supplied by farmer themselves. 12. Sediment desposit in reservoir should be thoroughly dreged so as to secure a original design storage capacity. 13. The structure of overflow weir should be automatic so as to freely control flood level and not to increase dam height.

• Clinical and Experimental Pediatrics
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• v.49 no.10
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• pp.1079-1085
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• 2006

Purpose : The purpose of this study was to evaluate factors affecting hematologic recovery and infection in high-dose chemotherapy(HDCT) and autologous stem cell transplantation(ASCT) in patients with high-risk solid tumor. Methods : From January 2004 to December 2005, 72 HDCTs and ASCTs were applied to children with high-risk solid tumor at Samsung Medical Center. Medical records of these 72 HDCTs and ASCTs were retrospectively analyzed. Results : The single most powerful predictor of neutrophil and platelet recovery was the number of transplanted $CD34^+$ cells. The duration of high fever was significantly longer in young patients, in patients treated with total body irradiation and/or thiotepa, and in patients transplanted with lower $CD34^+$ cell dose(<$2{\times}10^6/kg$). However, the difference in the duration of high fever according to the number of $CD34^+$ cells was not clinically significant. Conclusion : Findings in this study suggest that HDCT and ASCT with low $CD34^+$ cell dose is clinically feasible despite delayed hematologic recovery, especially at a dose >$1{\times}10^6/kg$ per transplantation. Therefore, it is important not to defer the appropriate time for HDCT for an additional collection of hematopoietic stem cells if the number of collected $CD34^+$ cells is >$1{\times}10^6/kg$ per transplantation.

• Journal of Intelligence and Information Systems
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• v.17 no.3
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• pp.131-146
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• 2011

It is becoming more essential than ever for office professionals to become competent in information collection/gathering and problem solving in today's global business society. In particular, office professionals do not only assist simple chores but are also forced to make decisions as quickly and efficiently as possible in problematic situations that can end in either profit or loss to their company. Since office professionals rely heavily on their tacit knowledge to solve problems that arise in everyday business situations, it is truly helpful and efficient to refer to similar business cases from the past and share or reuse such previous business knowledge for better performance results. Case-based reasoning(CBR) is a problem-solving method which utilizes previous similar cases to solve problems. Through CBR, the closest case to the current business situation can be searched and retrieved from the case or knowledge base and can be referred to for a new solution. This reduces the time and resources needed and increase success probability. The main purpose of this study is to design a system called COKRS(Case-based reasoning Office Knowledge Recommender System) and develop a prototype for it. COKRS manages cases and their meta data, accepts key words from the user and searches the casebase for the most similar past case to the input keyword, and communicates with users to collect information about the quality of the case provided and continuously apply the information to update values on the similarity table. Core concepts like system architecture, definition of a case, meta database, similarity table have been introduced, and also an algorithm to retrieve all similar cases from past work history has also been proposed. In this research, a case is best defined as a work experience in office administration. However, defining a case in office administration was not an easy task in reality. We surveyed 10 office professionals in order to get an idea of how to define a case in office administration and found out that in most cases any type of office work is to be recorded digitally and/or non-digitally. Therefore, we have defined a record or document case as for COKRS. Similarity table was composed of items of the result of job analysis for office professionals conducted in a previous research. Values between items of the similarity table were initially set to those from researchers' experiences and literature review. The results of this study could also be utilized in other areas of business for knowledge sharing wherever it is necessary and beneficial to share and learn from past experiences. We expect this research to be a reference for researchers and developers who are in this area or interested in office knowledge recommendation system based on CBR. Focus group interview(FGI) was conducted with ten administrative assistants carefully selected from various areas of business. They were given a chance to try out COKRS in an actual work setting and make some suggestions for future improvement. FGI has identified the user-interface for saving and searching cases for keywords as the most positive aspect of COKRS, and has identified the most urgently needed improvement as transforming tacit knowledge and knowhow into recorded documents more efficiently. Also, the focus group has mentioned that it is essential to secure enough support, encouragement, and reward from the company and promote positive attitude and atmosphere for knowledge sharing for everybody's benefit in the company.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.3
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• pp.131-138
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• 1988

Collection of organisms for the fisheries resources community were obtained with a set net during 8 months between May, 1985 and May, 1986 on the coast of Pukchon, Cheju Island, Korea. Most of organisms, representing 36 species, were less than 20cm $(93\%)$ in length, and 130g $(91\%)$ in weight. The four most abundant species were jack mackerel, Trachurus japonicus ; squid, Todarodes pacificus : damsel fish, Chromis notatus : and rabbit fish, Siganus fuscescens, which comprised about $83\% in number and about $73\%$ of the total catch. The diversity index of the number of species and information indices for individual and catch were the highest in October and the lowest in Septemer, indicating a close relationship with the change between the species number and catch at that time. A cluster analysis of 17 species was illustrated from the similarity matrix. All of the 17 species were grouped at the 0.2 similarity level. Three groups were present at 0.60 level, whereas species in other groups were sporadic in occurrence.

• Journal of Global Scholars of Marketing Science
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• v.20 no.1
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• pp.27-34
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• 2010

During the past 10 years, sales of luxury goods increased significantly to more than US$ 130 billion in 2007. In this industry, more than half of the revenue comes from Asia where the average income has risen significantly, and the demand for luxury products is forecast to grow rapidly. Purchasing luxury brands appears to be an intriguing social phenomenon that is profitable for companies in this region. As a newly developed country, Korea is one of the most attractive luxury markets in Asia. Currently, a total of 120 luxury fashion brands have entered the Korean market, primarily in luxury districts in Seoul where the competition is fierce. The purposes of this study are to: (1) identify antecedents of attitude toward luxury brands, (2) examine the effect of attitudes toward luxury brands on customer equity, (3) determine the impact of attitudes toward luxury brands on customer lifetime value, and (4) investigate the influence of customer equity on customer life time value. Previous studies have examined materialism, social need, experiential need, need for uniqueness, conformity, and fashion involvement as antecedents of attitude toward luxury brands. Richins and Dowson (1992) suggested that that materialism influences consumption behavior relative to quantity of goods purchased. Nueno and Quelch (1998) reported that the ownership of luxury brands conveys information related to the owner's social status, communicates an image of success and prestige, and is a determinant of purchase behavior. Experiential need is recognized as an important aspect of consumption, especially for new products developed to meet consumer demand. Since luxury goods, by definition are relatively scarce, ownership of these types of products may fulfill consumers' need for uniqueness. In this study, value equity, relationship equity, and brand equity are examined as drivers of customer equity. The sample (n = 114) was undergraduate and graduate students at two private women's universities in Seoul, Korea. Data collection was conducted using a self-administered questionnaire survey in March, 2009. Data analysis included descriptive statistics, factor analysis, reliability analysis, and regression analysis using SPSS 15.0 software. Data analysis resulted in a number of conclusions. First, experiential need and fashion involvement positively influence participants' attitude toward luxury brands. Second, attitude toward luxury brands positively influences brand equity, followed by value equity and relationship equity. However, there is no significant relationship between attitude toward luxury brand and customer lifetime value. Finally, relationship equity positively influences customer lifetime value. In conclusion, young consumers are an important potential consumer group that tries different brands to discover the ones most suitable for them. Luxury marketers that use effective marketing strategies to attract and engender loyalty among this potentially lucrative consumer group may increase customer equity and lifetime value.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.2
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• pp.161-170
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• 1997

This is an effort to confirm changes biological monitoring according to changes in levels of exposure to styrene for industrial workers. This study was conducted on 108 workers, including male of 64 and female 44 who were working at factories of FRP, dipping, and coating. An improved passive monitor method(organic vapor monitor; OVM) was employed to determine levels of exposure. The biological monitoring include blood styrene concentration, urinary mandelic acid(MA), and urinary phenylglyoxylic acid(PGA). Biological monitoring were made through the Collection of blood and urine. The mean value of exposure to styrene was 21.0ppm, which is measured by organic vapor monitor, one of improved passive monitors. The highest exposure level was observed among workers in boat factories, laminating procedure workers, processing workers, respectively(p<0.01). For exposure level, 11% of subjects under study showed over 50ppm which is time weighted average(TWA). The correlation coefficient between biological specimens and the exposure level was 0.62 for blood styrene concentration, 0.58 for MA corrected by creatinine, and 0.70 for PGA corrected by creatinine, respectively(p<0.01). The regression analyses found exposure level relative importance in explaining variance in biological monitoring. In additional to that, gender was a significant factor in explaining variance of MA and MA+PGA. Almost half of variance(49%) in blood styrene concentration was explained by predictors, including exposure level, age, gender, duration, and drinking volume during the last week(p<0.01). The very high correlation(higher than 0.95 was found when a comparison was made among three types of corrected methods, including uncorrected specific gravity and creatinine. In conclusion, these findings suggest OVM to represent levels of exposure to styrene for industrial workers. A discussion was made on possible use of specific gravity sample for biological monitoring. Exposure level may be predicted on MA, PGA in urine, which could be applied to represent biological monitoring.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.175-182
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• 2001

The main focus of this study was set to help college students in Kangwon province to improve and correct dietary habits and to maintain healthy life. The nutritional status and food preference of college students were examined from May to July, 1999. The collection of the research data has been made on the basis of questionnaries for 184 college students residing in Kangwon province. Statistical analysis of the data was performed using SAS package program for descriptive frequency and statistical significance. The meal skipping ratio of the subjects were 2% and for the reasons of meal skipping 45% responded "lack of time". As for main dishes, cooked rice turned out to be the most preferred by the subjects and the second and third favored by female students were bread and noodle respectively. Most preferred side-dishes were meat soup, kimchi, laver Kui,squid Bockeum, fried squid, beef Chon, squid Chorim, soy Namul, Dubuk Changachi and squid Muchim. Less preferred side-dishes include radish soup, white kimchi, mugwort fry, liver Bockeum, liver sheon and egg plant Kui. No one-plate food was disliked by the subjects. Male liked Manndukuk and female liked cuttle fish rice. The intakes of nutrient except for energy, iron and calcium for female students were the same or above the Recommended Dietary Allowances (RDA) for Koreans.

• Journal of Korean Academy of Nursing
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• v.22 no.4
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• pp.636-652
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• 1992

This study identified the impact of childhood cancer on the Korean family. The purpose was to contribute knowledge for family nursing and pediatric hospice care practice with sick children and their families. This descriptive study was conducted during a 6 month period with children who were being treated for cancer at six university hospitals in Seoul. The data were gathered from members of 68 families ; 24(Group A), with a child newly diagnosed with cancer : 27(Group B), with a child under treatment and without complications, and 17 (Group C), with a child in relapse. Medical records, structured questionnaires and interviews were used for data collection. The questionnaires and interview schedules had been used previously in Martinson's research in the USA and China. The findings, conclusions, and suggestions are as follows. 1. The impact of childhood cancer on the family. Members of the family experienced fear, helplessness, guilty feelings, and anger at the time of the initial diagnosis and at relapse. Mothers complained of headache, anorexia and poor appetite, weight loss, sleep disturbance, and bad dreams. Many of the fathers either lost or changed jobs, and all working mothers stopped working. Half the parents reported changes in their marital relationships such as frequent quarrels but also stronger unity. Family members perceived cancer as the most frightening disease. Change in their world view was expressed as living on faith understanding suffering, determining to live a better life, wanting to live an upright life and valuing health as the most important. Religious activities are found most helpful through this difficult experience. Financial debt due to the treatment and care of the sick child, burdened 22 families. The above mentioned impact was most evidant in Group B(those presently undergoing treatment) and Group C(those in relapse). Findings indicate that nursing care should embrace the family of a child who is being treated for cancer. 2. Characteristics of the child with cancer The majority of the children in this sample had a diagnosis of leukemia. Their mean age was 6.8 and the ratio of boys to girls was 1.12 ; 1. The mean hospitalization frequency was 13.5 times and the mean duration of illness was 16.8 months. Most of 1.he children perceived cancer as the most frightening disease ; 32.7% of the children described their sickness as serious. Children in Group C were hospitalized more frequently, stayed in hospital for longer periods, and expressed their sickness as quite serious more often than the other two groups. These findings indicate how much comprehensive pediatric hospice nursing care services are needed along with relevant research and nursing education. 3. Characteristics of the families. The mean age of the father was 39.5 and the mother, 36,6 ; they are in their most productive life period. Mothers especially expressed feelings of financial uneasiness and powerlessness about giving up their jobs, and guilty feelings for not providing enough care and concern to other children due to taking care of the sick one. The burden of caring for the sick child can bring negative changes in family dynamics which they think provoke potential health problems in members of the family These findings suggest a need for nursing support and counselling resources. Findings also suggest the need for ethical inquiry about such questions as who should give information to the child in regard to diagnosis and prognosis, when, and how. Other suggestions included : 1) Quality health care for childhood cancer such as home care and pediatric hospice programs should be established. 2) Special and practical consideration for long-term patients should be made in the present insurance coverage. The reimbursement period for long-term patients should be lengthened. 3) Further in-depth qualitative studies are needed. 4) Education programs including guided practice experience for pediatric hospice care practitioners are needed.