• Journal of Intelligence and Information Systems
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• v.19 no.2
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• pp.39-54
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• 2013

Recent explosive increase of electronic commerce provides many advantageous purchase opportunities to customers. In this situation, customers who do not have enough knowledge about their purchases, may accept product recommendations. Product recommender systems automatically reflect user's preference and provide recommendation list to the users. Thus, product recommender system in online shopping store has been known as one of the most popular tools for one-to-one marketing. However, recommender systems which do not properly reflect user's preference cause user's disappointment and waste of time. In this study, we propose a novel recommender system which uses data mining and multi-model ensemble techniques to enhance the recommendation performance through reflecting the precise user's preference. The research data is collected from the real-world online shopping store, which deals products from famous art galleries and museums in Korea. The data initially contain 5759 transaction data, but finally remain 3167 transaction data after deletion of null data. In this study, we transform the categorical variables into dummy variables and exclude outlier data. The proposed model consists of two steps. The first step predicts customers who have high likelihood to purchase products in the online shopping store. In this step, we first use logistic regression, decision trees, and artificial neural networks to predict customers who have high likelihood to purchase products in each product group. We perform above data mining techniques using SAS E-Miner software. In this study, we partition datasets into two sets as modeling and validation sets for the logistic regression and decision trees. We also partition datasets into three sets as training, test, and validation sets for the artificial neural network model. The validation dataset is equal for the all experiments. Then we composite the results of each predictor using the multi-model ensemble techniques such as bagging and bumping. Bagging is the abbreviation of "Bootstrap Aggregation" and it composite outputs from several machine learning techniques for raising the performance and stability of prediction or classification. This technique is special form of the averaging method. Bumping is the abbreviation of "Bootstrap Umbrella of Model Parameter," and it only considers the model which has the lowest error value. The results show that bumping outperforms bagging and the other predictors except for "Poster" product group. For the "Poster" product group, artificial neural network model performs better than the other models. In the second step, we use the market basket analysis to extract association rules for co-purchased products. We can extract thirty one association rules according to values of Lift, Support, and Confidence measure. We set the minimum transaction frequency to support associations as 5%, maximum number of items in an association as 4, and minimum confidence for rule generation as 10%. This study also excludes the extracted association rules below 1 of lift value. We finally get fifteen association rules by excluding duplicate rules. Among the fifteen association rules, eleven rules contain association between products in "Office Supplies" product group, one rules include the association between "Office Supplies" and "Fashion" product groups, and other three rules contain association between "Office Supplies" and "Home Decoration" product groups. Finally, the proposed product recommender systems provides list of recommendations to the proper customers. We test the usability of the proposed system by using prototype and real-world transaction and profile data. For this end, we construct the prototype system by using the ASP, Java Script and Microsoft Access. In addition, we survey about user satisfaction for the recommended product list from the proposed system and the randomly selected product lists. The participants for the survey are 173 persons who use MSN Messenger, Daum Caf$\acute{e}$, and P2P services. We evaluate the user satisfaction using five-scale Likert measure. This study also performs "Paired Sample T-test" for the results of the survey. The results show that the proposed model outperforms the random selection model with 1% statistical significance level. It means that the users satisfied the recommended product list significantly. The results also show that the proposed system may be useful in real-world online shopping store.

• Journal of Intelligence and Information Systems
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• v.17 no.3
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• pp.43-61
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• 2011

In this research, we propose a dynamic decision making using social context based on ontology. Dynamic adaptation is adopted for the high qualified decision making, which is defined as creation of proper information using contexts depending on decision maker's state of affairs in ubiquitous computing environment. Thereby, the context for the dynamic adaptation is classified as a static, dynamic and social context. Static context contains personal explicit information like demographic data. Dynamic context like weather or traffic information is provided by external information service provider. Finally, social context implies much more implicit knowledge such as social relationship than the other two-type context, but it is not easy to extract any implied tacit knowledge as well as generalized rules from the information. So, it was not easy for the social context to apply into dynamic adaptation. In this light, we tried the social context into the dynamic adaptation to generate context-appropriate personalized information. It is necessary to build modeling methodology to adopt dynamic adaptation using the context. The proposed context modeling used ontology and cases which are best to represent tacit and unstructured knowledge such as social context. Case-based reasoning and constraint satisfaction problem is applied into the dynamic decision making system for the dynamic adaption. Case-based reasoning is used case to represent the context including social, dynamic and static and to extract personalized knowledge from the personalized case-base. Constraint satisfaction problem is used when the selected case through the case-based reasoning needs dynamic adaptation, since it is usual to adapt the selected case because context can be changed timely according to environment status. The case-base reasoning adopts problem context for effective representation of static, dynamic and social context, which use a case structure with index and solution and problem ontology of decision maker. The case is stored in case-base as a repository of a decision maker's personal experience and knowledge. The constraint satisfaction problem use solution ontology which is extracted from collective intelligence which is generalized from solutions of decision makers. The solution ontology is retrieved to find proper solution depending on the decision maker's context when it is necessary. At the same time, dynamic adaptation is applied to adapt the selected case using solution ontology. The decision making process is comprised of following steps. First, whenever the system aware new context, the system converses the context into problem context ontology with case structure. Any context is defined by a case with a formal knowledge representation structure. Thereby, social context as implicit knowledge is also represented a formal form like a case. In addition, for the context modeling, ontology is also adopted. Second, we select a proper case as a decision making solution from decision maker's personal case-base. We convince that the selected case should be the best case depending on context related to decision maker's current status as well as decision maker's requirements. However, it is possible to change the environment and context around the decision maker and it is necessary to adapt the selected case. Third, if the selected case is not available or the decision maker doesn't satisfy according to the newly arrived context, then constraint satisfaction problem and solution ontology is applied to derive new solution for the decision maker. The constraint satisfaction problem uses to the previously selected case to adopt and solution ontology. The verification of the proposed methodology is processed by searching a meeting place according to the decision maker's requirements and context, the extracted solution shows the satisfaction depending on meeting purpose.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.44
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• pp.377-391
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• 1997

We consider the characterized curriculum of industrial engineering for training the excellent technician. We classified many kinds of jobs in the industry and information society and compared them with the curriculums of 13 junior colleges sampled randomly. Also we inquired the degree of relation of the technique qualification for graduates from industrial engineering to the current major subjects. For fostering the cultured individuals the community demands, we amended and looked into the current liberal arts course to supplement it. We analyzed the opinions of students, professors and experts from various circles through questionnaires, and then we set up the direction and the priority order for developing the curriculum for training the technician. According to the analyzed results, we presented the curriculum centering around customers and demanders and introduced it in detail. We are going to utilize developed curriculum, teaching methods by computers and practice methods step by step, and make expansion to industrial engineering of other colleges. Then we are planning to apply to the reeducation for graduates and the social education that contains the industrial human resources and the ordinary persons.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.2
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• pp.103-109
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• 2010

The edit distance problem is finding the minimum number of edit operations to transform a string into another one. It is one of the important problems in algorithm research and there are some algorithms that compute an optimal edit distance for the one-dimensional languages such as the English alphabet. However, there are a few researches to find the edit distance for the more complicated language such as the Korean or Chinese alphabet. In this paper, we define the measure of the edit distance for the Korean alphabet and present an algorithm for the edit distance problem for the Korean alphabet.

• Journal of Hospice and Palliative Care
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• v.19 no.1
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• pp.1-4
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• 2016

As advance care planning is taking center stage in the field of end-of-life care, various tools have been developed to aid in the often emotional and difficult decision-making process. Video decision support tools are one of the most promising means of assistance, of which the modus operandi is to provide more comprehensive and precise information of medical procedures to patients and their families, allowing them to make better informed decisions. Despite such value, some are concerned about its potential negative impact. For example, video footages of some procedures may be shocking and unpalatable to non-medical professionals, and patients and families may refuse the procedures. One approach to soften the sometimes unpleasant visual of medical procedures is to show less aggressive or more relaxing scenes. Yet another potential issue is that the objectivity of video decision support tools might be vulnerable to the very stakeholders who were involved in the development. Some might argue that having multiple stakeholders may function as checks and balances and provide collective wisdom, but we should provide more systematic guarantee on the objectivity of the visual decision aids. Because the decision of the modality of an individual's death is the last and most significant choice in one's life, no party should exert their influence on such a delicate decision. With carefully designed video decision support tools, our patients will live the last moments of their lives with dignity, as they deserve.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.142-152
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• 2014

This paper analyzes the conjunction events of Korea satellites by year or kind of satellite using CSM, which is provided by JSpOC. If multiple CSM for single conjunction event are available, consistency analysis is performed using minimum range of CSM. And this paper presents the contact analysis results with space objects if there is a radar system in Korea. The effectiveness of Korea's radar system is analyzed by calculating the access time or frequency with space objects. Furthermore, we investigate the radar systems of other space agencies and find the specific parameter depending on the operating environment. Using this information, we define the requirements of radar system, which is appropriate the Korea.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.115-124
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• 2013

Recently, there have been improvements in diagnostic methods for the assessment of early caries lesions. The reason is that dental professionals are seeking methods to reliably detect incipient dental caries and to remineralize them. This review examines the literature on principles, theoretical background, and history of the Quantitative Light-Induced Fluorescence (QLF) system (Inspektor Research Systems BV, The Netherlands). Furthermore, this paper discusses the potential application of QLF system to clinical practice for educational purpose, enabling dental hygiene students to perform oral health assessment using the QLF system. In addition, the clinical application of QLF system can motivate patients by providing additional visual information about caries and bacterial activity. The evidences on validity and reliability of the QLF system for detection of longitudinal changes in de/remineralization and caries were examined. The QLF system is capable of monitoring and quantifying mineral changes in early caries lesions. Therefore, it can be used to assess the impacts of caries preventive measures on the remineralization and reversal of the caries process. And the QLF system is a very promising equipment to assess educational effectiveness for dental hygiene students in their learning process. In conclusion, the QLF system is the most effective technology for more sensitive staging of caries and treatment without surgical intervention.

• Korean Institute of Interior Design Journal
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• v.21 no.1
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• pp.159-169
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• 2012

One of critical issues in the housing area is what strategies should be adopted for revitalizing contemporary communities in housing complex. It is expected that those strategies could encourage neighbourship and recover the existing community spaces. Based on the assumption that contemporary communities might have different characteristics from those of the traditional communities and spaces, this research aims to explore the possibility of new communities in a current context. With the development of the information communication technologies (ICT) and hardware systems, the environment would be capable of anticipating people's needs and then provide them with customization options to tailor the environment to their requirements. By incorporating the 'smart' paradigm, this paper introduces the concept of a smart community and space with the potential of mobile Augmented Reality(AR) as alternative strategies for activating the communities. The residents believe that existing common spaces need to be extendable and augmented by combining new technologies. The smart communities and spaces are expected to extend people's interaction to virtual world in aj real context, further combined with social network, it enables sustainable relationships among residents, contributina to a new type of community.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.193-199
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• 2013

Today, university students are suffering from various stresses such as individual capacity development, school score management, human relationships, job placement, and English study for preparation as member of society the future. However, stress of students decreases stabilization of mind and aggravate feeling of satisfaction of life. In this research, we examined the relationships among stress, mindfulness and life satisfaction among university students. In addition, we analyzed the moderating effect as university class levels on stress and life satisfaction using partial least squares. This results provide useful implications for decreasing stress, improving mindfulness, and increasing life satisfaction among university students.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.4
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• pp.129-139
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• 1985

Small-scale hydropower systems offer several advantages compared to other alternatives as an important source of energy in both developed and developing countries. This study proposes systematic criteria for screening of small-scale hydropower sites to determine their potential for farther study, and demonstrates the general procedure. These criteria are based on the physical characteristics of the sites and their social, environmental and economic aspects. The procedure presented shows great flexibility for screening based on the availability of information and situation at the site.