• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.6
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• pp.2240-2254
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• 2021

We investigate the channel allocation problem in an ultra-dense device-to-device (D2D) enabled cellular network in underlaying mode where multiple D2D users are forced to share the same channel. Two kinds of low complexity solutions, which just require partial channel state information (CSI) exchange, are devised to resolve the combinatorial optimization problem with the quality of service (QoS) guaranteeing. We begin by sorting the cellular users equipment (CUEs) links in sequence in a matric of interference tolerance for ensuring the SINR requirement. Moreover, the interference quota of CUEs is regarded as one kind of communication resource. Multiple D2D candidates compete for the interference quota to establish spectrum sharing links. Then base station calculates the occupation of interference quota by D2D users with partial CSI such as the interference channel gain of D2D users and the channel gain of D2D themselves, and carries out the channel allocation by setting different access priorities distribution. In this paper, we proposed two novel fast matching algorithms utilize partial information rather than global CSI exchanging, which reduce the computation complexity. Numerical results reveal that, our proposed algorithms achieve outstanding performance than the contrast algorithms including Hungarian algorithm in terms of throughput, fairness and access rate. Specifically, the performance of our proposed channel allocation algorithm is more superior in ultra-dense D2D scenarios.

• Journal of the Korean Home Economics Association
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• v.42 no.7
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• pp.1-17
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• 2004

This study was conducted to determine the influence of socio-economic status of potential consumers on the types of senior congregate housing(SCH) among 4 urban areas(Seoul Metropolitan area, Busan, Gwangaju, and Daejun). This study was part or a research series to develop SCH which meets the korean situation. The Questionnaire used for the final analysis involved 1006 people and SPSS Windows program was used for statistical analysis. The opinion about SCH should differ among the 4 urban areas according to Socio-Economic Status(SES). The results of this study were as follows: The opinions on SCH varied in each region according to SES indicating that diverse constructions of senior housing to meet selective needs of the old can create high demand in a construction market. In order to induce active participation of the private sector, the Ministry of Construction and Transportation, rather than the Ministry of Health and Welfare, should be in charge of the development of SCH. This is desirable in the perspective of developing new types of housing as for general housing. In this case, the Ministry of Construction and Transportation should consider geographic locations and environmental factors of each city. Moreover, the successful development of SCH needs an effort to reexamine an appropriate development plan rather than adopting the cases of developed countries without criticism. In terms of policies, the government should provide financial support for building sharing space, give an exception on a measurement rate, assist in the education of supervisors and establish a management system and so on.

• Industrial Engineering and Management Systems
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• v.8 no.2
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• pp.80-92
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• 2009

This paper addresses the inventory rationing issue embedded in the regional supply chain inventory replenishment problem (RSIRP). The concerned supply chain, which was fed by the national supply chain, consisted of a single warehouse distributing a single product to multiple stores (M-stores) with independent and normally distributed customer demand. It was assumed that the supply chain operated under the order-up-to level inventory replenishment system and had only one truck at the regional warehouse. The truck could make one replenishment trip to one store per period (a round trip per period). Based on current inventories and the vehicle constraint, the warehouse must make two decisions in each period: which store in the region to replenish and what was the replenishment quantity? The objective was to position inventories so as to minimize lost sales in the region. The warehouse inventory was replenished in every fixed-interval from a source outside the region, but the store inventory could be replenished daily. The truck destination (store) in each period was selected based on its maximum expected shortage. The replenishment quantity was then determined based on the predetermined order-up-to level system. In case of insufficient warehouse inventories to fulfill all projected store demands, an inventory rationing rule must be applied. In this paper, a new inventory rationing rule named Expected Cost Minimization (ECM) was proposed based on the practical purpose. The numerical results based on real data from a selective industry show that its performance was better and more robust than the current practice and other sharing rules in the existing literature.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.3
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• pp.57-67
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• 2007

Researchers in mobile AR systems have so far put the value on the technical challenges involved in the limitations imposed from mobility. Beyond such immediate technical questions, however, are questions regarding the possible contents that are to be used for the user’s interaction in ubiquitous computing environment. Various aspects of context of user and environment can be utilized easily as well as effectively. Moreover, the environment will be equipped with lots of pervasive but invisible computing resources. However, it is difficult for users to have access to those computing resources. At the same time, as the smart appliances get to have more features, their user interfaces tend to become harder to use. Thus, in this paper, we propose Context-Aware Mobile Augmented Reality (CAMAR) system. In our system, users only need to take a picture of smart appliances with a built-in camera in a mobile device when they intend to control the appliances. It lets users interact with the smart appliances through personalized control interfaces on their mobile devices. Also, it supports enabling contents to be not only personalized but also shared selectively and interactively among user communities.

• The Journal of the Korea Contents Association
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• v.21 no.9
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• pp.446-457
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• 2021

The aim of this study was to grasp the seriousness of depression problems in medical students by examining the research trends among them and to present desirable direction of the future study. A selective search has been conducted for literature published in Nurimedia (DBPIA), Korean studies Information Service System (KISS), Research Information Sharing Service (RISS), National Assembly Library (NANET) and National Digital Science Library (NDSL) databases. 18 papers have been selected for the final analysis. The results showed that studies on depression problems were published in very small proportion which researchers with diverse majors including psychiatry participated. Second, most of depression assessment tools usually measured depression only while some did various psychological symptoms. Third, independent t test was the most frequent analytic method. Last but not least, there was no research dealing with intervention about depression in medical students. To sum up, though numerous researchers with diverse specialties participated in the depression study and analyzed the data using various analyses and variables, there is a lack of intervention for depression of the medical students. Therefore, it is necessary to emphasize the necessity of practical intervention based on the evidence-based practice.

• 대한공업교육학회지
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• v.39 no.1
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• pp.189-208
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• 2014

The purpose of this research was to investigate the critical issues and practical strategies that Korean technology teachers perceived. To accomplish the purpose of this study, a qualitative study was conducted to identify critical issues and practical strategies of Korean technology education targeted on Korean technology teachers. A purposeful sampling for choosing technology teachers was used for this study with three selection conditions: 1) 'Excellent Korean technology teacher' award winning teachers, or 2) technology teachers actively involved in both on-line and off-line teachers' association, and 3) leaders in local technology teachers' association. This study conducted exploratory in-depth interviews with selective 15 technology teachers regarding critical issues and practical strategies of Korean technology teachers. The interpretation of the interview content was conducted by two researchers using the thematic analysis which analyzed the frequency of concepts, words, and meanings held from collected data. In the conclusion, critical issues researchers identified were 1) curriculum problems, 2) education environment and facilities problems, 3) teachers' problems, 4) students' problems, 5) related research institution and college problems, 6) social problems. Secondly, Korean technology teachers agreed with following practical strategies 1) separating technology education from home economic education, 2) sharing practices on managing and improving educational environment and laboratory for technology education, 3) actively involving in technology teachers' group, 4) motivating students using hands-on activity 5) improving the quality and the quantity on technology teachers preparatory institution, 6) advertising the values of technology education to the public. Lastly, the positive factors to succeed technology education were 1) technology education satisfying social needs and 2) technology teachers' will or passion toward improving their technology classrooms. The negative factors to hinder technology education were 1) low self-respect of Korean technology teachers and 2) rejection or retarded acceptance toward social transition. Several recommendations based the conclusion were suggested as 1) implementing supplementary study toward selected critical issues and 2) conducting exemplary case studies regarding concrete practical strategies for improving challenges of Korean technology education.