• The KIPS Transactions:PartC
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• v.15C no.3
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• pp.205-212
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• 2008

In the environment with multiple heterogeneous wireless sensor networks with a single point of sensed data collection or a gateway (GW), relay points (RPs) may be required for the energy efficient delivery of sensed data from static or mobile sinks to the GW. The optimal placement of RPs becomes an even more difficult problem if static sinks are dynamically added or the trajectory of mobile sinks can not be known in advance. In order to resolve this problem, we propose a mechanism to deploy RPs in a grid pattern and to use the tree-based relaying network for reducing the cost of the RP and for reducing the control overhead incurred by the route setup from sinks to the GW. For the performance evaluation of our proposed mechanism, we have carried out a numerical analysis on a single route setup from a sink to the GW and, for more general performance evaluations, ns-2 based simulations have been carried out. According to the performance evaluation results, our tree-based relaying network mechanism outperforms that based on AODV in terms of the data delivery time, the network service time and the control overhead.

• Korea Journal of Hospital Management
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• v.23 no.1
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• pp.28-40
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• 2018

Purpose: The purpose is to understand the perception of medical providers at tertiary hospitals in Seoul on the importance-performance of the reform on a doctor-designation system, and to provide the policy suggestion of the perception on such a system. Methodology: To achieve the purpose, this study utilized structured survey tools to conduct a questionnaire survey of nursing, administrative and medical technology professionals at six tertiary hospitals in Seoul. An importance-performance analysis was utilized for an analysis that showed the perception of the reform on a doctor-designation system. Findings: First, it was identified that those medical providers had the highest perception of the importance about the performance of the reform on a doctor-designation system. Second, according to the result of action grid of an importance-performance analysis (IPA), it can be identified that in the 2nd stage of 'Concentrate here' included are the items as to design and effect of medical care quality and subsidies & patient infection and safety and control fees, effect of income security of the method for compensating for loss established by the government and offering sufficient information on general medical services and doctor-designation medical services. In the 1st stage of 'Keep up the Good Work', and the 2nd stage of 'Concentrate here' included is the item as to the performance of patients of the reform on a doctor designation system. Practical Implications: There could be identified the effect of the reform bill on the perception of medical providers. It is expected that a better environment would be provided for patients to use a hospital and for medical providers to offer medical services, if the goverment makes efforts to improve methods for compensating for loss and continuous monitoring of the performance of patients.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.5
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• pp.19-28
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• 2012

Recently a grid and cloud computing collaboration have become a social issue. These collaborative network system, the P2P system based on this system. Distingui shed from the client/server systems, P2P systems in order to exchange information, its purpose and functions are divided according to the morphological Category. In accordance with the purposes and functions of information and data retrieval, remote program control and integration services for the offers. Most P2P systems client/server scalability, and management takes the form, but to overcome the disadvantages in terms of applying the mixed-mode system is increasing. And recently the distributed computing aspects of the service to users in order to provide suitable to accommodate the diverse needs of various types of mobile agent technology is needed. In this paper, as required by the mobile agent access to a remote resource access control and agent for the execution and management capabilities and improve the reliability of the mobile agent system designed to suggest.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.149-157
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• 2009

Tracking technologies which provide real-time and customized information through various information collecting and processing for pedestrians who use traffic connective and transferring center have been being examined. However some problems are caused due to the wide-range positioning error for some services as device installation and service place. It is also difficult to be applied to traffic linkage and transfer services because many situations can be barren. In the testbed, Gwangmyoung Station, we got some results in bad conditions such as a lot of steel construction and another communication device. Practically, conditions of the place which will be built can be worse than Gwangmyoung station. Therefore, we researched suitable Location correction algorithm as a method for accuracy to traffic connective and transferring system. And its algorithm is designed through grid coordinates, map-matching, modeling coordinates and Kalman filtering and is being implemented continuously. Also preparing for optimization of various transferring center model, we designed for simulator type algorithm what is available for deciding algorithm factor.

• Health Policy and Management
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• v.26 no.3
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• pp.233-241
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• 2016

Background: This study purposed to analyze and understand how spatial accessibility of patients influenced the number of outpatient visits for the internal medicine of a hospital. Methods: A hospital with 100 beds in Seoul, South Korea provided data from 2013 January 1 to 2013 June 30. Euclidean distance and road ares were used to represent the spatial accessibility. Patient level data and dong level data were collected and used in spatial analysis. Dong level data was converted into grid level ($500{\times}500m$) for the multivariate analysis. Hot-spot analysis and generalized linear model were applied to the data collected. Results: Hot-spots of outpatient visits were found around the study hospital, and cold-spots were not found. Number of outpatient visits was varied by the distance between patient resident and hospitals, and about 80% of total outpatient visits was occurred in within the 5 km from study hospital, and 50% was occurred in within 1.6 km. Spatial accessibility had significant influences on the outpatient visits. Conclusion: Findings provide evidences that spatial accessibility had influences on the patients' behaviors in utilizing the outpatient care of internal medicine in a hospital. Results can provide useful information to health policy makers as well as hospital managers for their decision making.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.1
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• pp.63-73
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• 2010

A comprehensive mapping project for agroclimatic zoning in South Korea will end by April 2010, which has required 4 years, a billion won (ca. 0.9 million US dollars) and 22 experts from 7 institutions to complete it. The map database from this project may be categorized into primary, secondary and analytical products. The primary products are called "high definition" digital climate maps (HD-DCMs) and available through the state of the art techniques in geospatial climatology. For example, daily minimum temperature surfaces were prepared by combining the climatic normals (1971-2000 and 1981-2008) of synoptic observations with the simulated thermodynamic nature of cold air by using the raster GIS and microwave temperature profiling which can quantify effects of cold air drainage on local temperature. The spatial resolution of the gridded climate data is 30m for temperature and solar irradiance, and 270m for precipitation. The secondary products are climatic indices produced by statistical analysis of the primary products and includes extremes, sums, and probabilities of climatic events relevant to farming activities at a given grid cell. The analytical products were prepared by driving agronomic models with the HD-DCMs and dates of full bloom, the risk of freezing damage, and the fruit quality are among the examples. Because the spatial resolution of local climate information for agronomic practices exceeds the current weather service scale, HD-DCMs and the value-added products are expected to supplement the insufficient spatial resolution of official climatology. In this lecture, state of the art techniques embedded in the products, how to combine the techniques with the existing geospatial information, and agroclimatic zoning for major crops and fruits in South Korea will be provided.

• The Journal of the Korea Contents Association
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• v.12 no.2
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• pp.30-39
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• 2012

In these day, some of IT venders already were going to cloud computing market, as well they are going to expand their territory for the cloud computing market through that based on their hardware and software technology, making collaboration between hardware and software vender. Distributed file system is very mainly technology for the cloud computing that must be protect performance and safety for high levels service requests as well data store. This paper introduced distributed file system for cloud computing and how to use this theory such as memory database, Hadoop file system, high availability database system. now In the market, this paper define a very large distributed processing architect as a reference by kind of distributed file systems through using technology in cloud computing market.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.904-914
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• 2017

For efficient energy usage, the concept of demand response has been emerged and thereby Open Automated D emand Response(OpenADR) protocol is developed as a standard protocol to provide automated demand response. There have been emerging trends on the demand response services using the Internet of Things(IoT) for smart h ome energy management. In this smart home energy IoT environment, a lightweight protocol is needed rather tha n the existing HTTP/ XML based OpenADR protocol for demand response services since many small devices wi ll be interconnected. In this paper, we propose a lightweight OpenADR protocol based on CoAP protocol for pro viding demand response service in Smart Energy IoT environment, implement the proposed CoAP-based protocol, and analyzed the performance compared to existing HTTP/ XML-based OpenADR 2.0b protocol.

• Atmosphere
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• v.27 no.2
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• pp.189-197
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• 2017

Progressing from weather forecasts and warnings to multi-hazard impact-based forecast and warning services represents a paradigm shift in service delivery. Urban flooding is a typical meteorological disaster. This study proposes support plan for urban flooding impact-based forecast by providing inundation risk matrix. To achieve this goal, we first configured storm sewer management model (SWMM) to analyze 1D pipe networks and then grid based inundation analysis model (GIAM) to analyze 2D inundation depth over the Gangnam drainage area with $7.4km^2$. The accuracy of the simulated inundation results for heavy rainfall in 2010 and 2011 are 0.61 and 0.57 in POD index, respectively. 20 inundation scenarios responding on rainfall scenarios with 10~200 mm interval are produced for 60 and 120 minutes of rainfall duration. When the inundation damage thresholds are defined as pre-occurrence stage, occurrence stage to $0.01km^2$, 0.01 to $0.1km^2$, and $0.1km^2$ or more in area with a depth of 0.5 m or more, rainfall thresholds responding on each inundation damage threshold results in: 0 to 20 mm, 20 to 50 mm, 50 to 80 mm, and 80 mm or more in the rainfall duration 60 minutes and 0 to 30 mm, 30 to 70 mm, 70 to 110 mm, and 110 mm or more in the rainfall duration 120 minutes. Rainfall thresholds as a trigger of urban inundation damage can be used to form an inundation risk matrix. It is expected to be used for urban flood impact forecasting.

• The Journal of Bigdata
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• v.5 no.1
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• pp.97-108
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• 2020

As the domestic electric power industry becomes a smart grid, big data platforms for demand management, facility management, and customer service have been deployed. However, due to the nature of the big data project, big data platforms take time to realize their value in the business processes. Therefore, it is not easy to evaluate the performance of the initial big data platforms using the known or theoretical evaluation methods. In this paper, we propose a methodology of big data platform performance evaluation based on specific information quality such as information completeness/sufficiency, information reliability, information relevancy, information comparability, information unbiasedness, timeliness of information, related to the volume, diversity, and velocity of big data.