• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.171-178
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• 2010

Pipeline structure is one of core underground infrastructure which transports primary sources. Since the almost pipeline structures are placed underground and connected each other complexly, it is difficult to monitor their structural health condition continuously. In order to overcome this limitation of recent monitoring technique, recently, a Ubiquitous Sensor Network (USN) system based on on-line and real-time monitoring system is being developed by the authors' research group. In this study, real-time pipeline health monitoring (PHM) methodology is presented based on electromechanical impedance methods using USN. Two types of damages including loosened bolts and notches are artificially inflicted on the pipeline structures, PZT and MFC sensors that have piezoelectric characteristics are employed to detect these damages. For objective evaluation of pipeline conditions, Damage metric such as Root Mean Square Deviation (RMSD) value was computed from the impedance signals to quantify the level of the damage. Optimal threshold levels for decision making are estimated by generalized extreme value(GEV) based statistical method. Throughout a series of experimental studies, it was reviewed the effectiveness and robustness of proposed PHM system.

• Journal of the Korean Geographical Society
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• v.31 no.2
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• pp.317-328
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• 1996

The purpose of this paper is to review the trend of research in geographical education since the launching of the Korean Geographical Society in 1945 and to suggest the areas and directions for future oriented research in geographical education. 422 articles (including 12 books) were reviewed and analized for this paper. The outputs of research in geographical education contributed in developing and improving the geographical education in primary and secondary school geography. But to achieve stable and desirable status as a subject in the school curriculum, research in geographical education has to be changed in its target areas and methods. The results and the suggestions of this study are summarized as follows: First, research in geographical education in diverse areas, especially in the areas of significance, aims and objectives, and psychology of geographical education should be preceded the revision of the school curriclum so that the results could be used as the basis information and evidences in decision making about the curriculum. Second, research in geographical education for affective domain and skill development should be implemented more actively in accordance to the trend of integration centering around the dicipline-inquiry skill and citizenship skill. More close relationship between the circles of geographical education and geography would be one of the ways to satisfy the social needs. Third, the linkage between primary and secondary school geography is crucial to the research in geographical education. Considering the sequence in human development research in geographical education for two levels of school should be conducted in more wide school-year span. Fourth, critical and prescriptive research in geographical education focusing on the individual, diciplinary, and social relevancy of the content of geographical education may be recommended. Finally, the outputs of the research in geographical education should be publicized more widely so that the rationale for justification of subject geography and geographical education may be shared with among the researchers, educational administrators, and practioners.

• Journal of the Korean Geographical Society
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• v.42 no.1 s.118
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• pp.96-120
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• 2007

The purpose of this study is to look into practical knowledge of geography teacher that lead the teacher's conduct in performance assessment situation. In Classroom all activity of teachers is their unique creature and the behavior which express teacher's knowledge and competency as expert. Practical knowledge can be seen as a system of understanding that guides the teacher s decision, which involves the construction of contents to teach, methods of instruction, resources to use etc. Therefore if we fully read the teacher's instruction, we have to understand the practical knowledge of teacher. As an ordinary activity of teaming and teaching, performance assessment is conducted on active learning and teaching situation and has intention to advance learning. Thus All evaluating behavior conducted by teacher can be understood through the practical knowledge of teacher. For this purpose a series of performance assessment scenes conducted by teacher were selected observed and captured the imagery, principles and rules of practical knowledge through the qualitative research method. The result supposed that practical knowledge influence the whole process of geography teacher's performance assessment activity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6C
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• pp.429-437
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• 2008

Multiple-input multiple-output (MIMO) techniques can be used for the spectral efficiency enhancement of the cellular systems, which can be categorized into spatial multiplexing (SM) and spatial diversity schemes. MIMO systems suffer a severe performance degradation due to the intercell interference from the adjacent cells as the mobile terminal moves toward the cell boundary. Therefore for the spectral efficiency enhancement, an appropriate transmission scheme for the given channel environment and reception scheme which can mitigate the intercell interference are required. In this paper, we propose an adaptive signal transmission/reception scheme for the spectral efficiency improvement of $M_R{\times}M_T$ MIMO systems, present the decision criteria for the adaptive operation of the proposed scheme, and demonstrate the performance gain. The proposed scheme performs adaptive transmission using spatial multiplexing and spatial diversity, and adaptive reception using maximal ratio combining (MRC) and intercell spatial demultiplexing (ISD) when the spatial diversity transmission is used at the transmitter. Spatial multiplexing/demultiplexing is performed at the high signal-to-interference ratio (SIR) range, and the transmit diversity in conjunction with the adaptive reception uses either conventional MRC or ISD which can mitigate the $M_R-1$ interference signals, based on the mobile location. For the performance evaluation of the proposed adaptive scheme, the probability density function (pdf) of the effective SIR for the transmission/reception methods in consideration are derived for $M_R{\times}M_T$ MIMO systems. Using the results, the average effective SIR and spectral efficiency are presented and compared with simulation results.

• Korean journal of communication and information
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• v.29
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• pp.233-269
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• 2005

The purpose of the study is to explore the characteristics of lawsuits against investigative reporting programs of the broadcast media. This study proposed three research questions: (1) what were the characteristics of court derisions on the investigative reporting programs? (2) what were the reasonings on which judges rely in the lawsuits for a right of reply? (3) what were the critical issues and how the libel laws were applied in balancing between the freedom of the press and the protection of individual rights. To answer these questions, the study employed quantitative and qualitative methods analysing 35 related cases. This study revealed that investigative reporting programs must deal with the Issues of 'public figures' and 'matters of public concern' to be protected under the freedom of the press. The study also found that the broadcast media must prove legitimate public interests and the truth of the facts to prevail in a case. In 1999, the Constitutional Court of Korea held that pubic figures in libel cases must be regarded differently from private figures. In accordance with the decision, the Supreme Court has applied differing criteria for public figures in libel cases. However, courts have not set a clear definition of the public figure yet. To advocate the freedom of the press, as the results of this study indicate, TV producers and journalists should behave lawfully in the course of newsgathering and provide the opportunities of reply for their news sources.

• Journal of the Economic Geographical Society of Korea
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• v.18 no.4
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• pp.415-430
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• 2015

Since the late 1990s Vinacafe has gone through strategic changes in corporate governance and managements due to an increase in the introduction of coffee MNCs, a growth of global demands in sustainable coffee, aging coffee tree, and the deterioration of coffee production with climate changes in Vietnam. Vinacafe has attempted to cope with these kinds of changes through strategies for equitization. Therefore, the main aim of this paper is to identify strategies for enhancing the competitiveness of the Vietnamese coffee industry by investigating changes in corporate governance and processes of coffee production and distribution. The equitization of Vinacafe has led to the enhancement of coffee competitiveness in two perspectives. Firstly, as it has decentralized decision-making from headquarter, subsidiaries have become able to strength their competitiveness themselves by introducing new technologies, improving coffee quality, and encouraging the introduction of eco-friendly production methods through cooperative relationships with stakeholders involved in coffee production and distributions in Vietnam. Secondly, it has also enhanced competitiveness through the diversification and effectiveness of coffee managements by intensifying the flexibility of contract with coffee farmers and diversifying coffee sales and supply chains in Vietnam.

• Spatial Information Research
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• v.14 no.1 s.36
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• pp.163-176
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• 2006

The concept of 'spatial association' explains spatial distribution pattern of geographical phenomenon based on similarity with neighborhoods, as in the Tobler's Law of Geography: 'Everything is related to everything else, but near things are more related than distant things.' In this study, we develop a time-series exploratory analysis tool for discovering temporal patterns of spatial association by combining spatial statistics and geo-visualization, and thus present a possibility to support spatial decision-making process. As for the spatial proximity weight matrix indispensable to measuring global and local spatial association, we employ a variety of flexible weighting schemes using geometric characteristics of areal unit. In addition, we renovate the existing visualization methods for more effective understanding of the procedures and results of time-series analysis on spatial association: for instance, temporal parallel coordinate plot with box plot, animated map for spatial association, and 3D Moran scatterplot. The feasibility of our system is verified by time-series analysis experiments on the spatial association of land price fluctuation rate for all administrative units in Korea, $1995{\sim}2004$.

• Journal of Korea Port Economic Association
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• v.28 no.1
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• pp.263-288
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• 2012

This study aims to define which factors will contribute to vitalization of Saemangeum New Port to secure international competitiveness in order to attract international shipping companies, shippers and forwarders in constructing Saemangeum New Port, and to propose subsequent implications. For research methods of the current study, a factor analysis and a decision making method of analytic hierarchy process(AHP) were used. Through precedent studies, total 11 measuring variables were selected including short entrance and exit channels, main infrastructure development project, tax cut and deregulation, and through a factor analysis, total 3 high rank evaluation factors including 'location and facilities', 'surrounding infrastructure and hydrophile property', and 'local policy and environment'. Analysis results summarizing a test of reliability of measuring variables in this study indicate that as Cronbach alpha coefficient of total 11 measuring variables were turned out to be over 0.8, it is surpassing general average 0.6, which means there is reliability.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.2
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• pp.91-98
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• 2017

Background & Object: Basic daily activity screening tool such as the Modified Barthel Index (MBI) has been used commonly in rehabilitation clinic and community based rehabilitation setting. Previous studies have shown the significant relations between the level of daily activities and driving ability on stroke or elderly people. However, there is a lack of studies to investigate the usefulness of MBI on prediction of driving ability for stroke patient. This study was to predict driving abilities of stroke survivor using Korean version Modified Barthel Index (K-MBI). Methods: A sample of 48 patients with stroke in rehabilitation hospital was recruited. All participants were tested level of basic daily activities using K-MBI. The driving ability of participants was tested using virtual reality driving simulator. The predictive validity was calculated of the K-MBI among pass or fail group of driving simulator test using receiver operating characteristics curves. Results: The cut-off score of >86.5 on the K-MBI is proper sensitivity to predict on driving performance ability. Conclusion: This pilot result offers clinical reference to therapists and caregivers for reasoning on driving recommendation period during rehabilitation stage of stroke survivors. Further studies need to identify prediction using real on-road test in a large population group.

• Journal of Digital Convergence
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• v.13 no.2
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• pp.215-225
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• 2015

This study was conducted to develop a severity-adjusted LOS(Length of Stay) model for knee replacement patients and identify factors that can influence the LOS by using the Korean National Hospital Discharge in-depth Injury Survey data. The comorbidity scoring systems and data-mining methods were used to design a severity-adjusted LOS model which covered 4,102 knee replacement patients. In this study, a decision tree model using CCS comorbidity scoring index was chosen for the final model that produced superior results. Factors such as presence of arthritis, patient sex and admission route etc. influenced patient length of stay. And there was a statistically significant difference between real LOS and adjusted LOS resulted from health-insurance type, bed size, and hospital location. Therefore the policy alternative on excessive medical utilization is needed to reduce variation in length of hospital stay in patients who undergo knee replacement.