• ETRI Journal
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• v.40 no.1
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• pp.51-60
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• 2018

In Long Term Evolution (LTE) cellular networks, the transmit power control (TPC) mechanism consists of two parts: the open loop (OL) and closed loop. Most cellular networks consider OL/TPC because of its simple implementation and low operation cost. The analysis of OL/TPC parameters is essential for efficient resource management from the cellular operator's viewpoint. In this work, the impact of the OL/TPC parameters is investigated for homogeneous small cells and heterogeneous small-cell/macrocell network environments. A mathematical model is derived to compute the transmit power at the user equipment, the received power at the eNodeB, the interference in the network, and the received signal-to-interference ratio. Using the analytical platform, the effects of the OL/TPC parameters on the system performance in LTE networks are investigated. Numerical results show that, in order to achieve the best performance, it is appropriate to choose ${\alpha}_{small}=1$ and $P_{o-small}=-100dBm$ in a homogenous small-cell network. Further, the selections of ${\alpha}_{small}=1$ and $P_{o-small}=-100dBm$ in the small cells and ${\alpha}_{macro}=0.8$ and $P_{o-macro}=-100dBm$ in the macrocells seem to be suitable for heterogeneous network deployment.

• Journal of Advanced Navigation Technology
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• v.24 no.1
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• pp.37-46
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• 2020

Multi-crew pilot license (MPL) is a new pilot licensing concept introduced and operated by ICAO. Mostly, candidates for MPL are educated and drilled with competency-based trainings (CBTs). In this paper, to present education and training measures for the domestic MPL application, ICAO documents and Korea aviation laws for pilot licensing, domestic and foreign airlines' employee requirements, and status of operations related to MPL system are identified. Also feasibility of MPL application in Korea is reviewed by checking approved domestic aviation training institutions' capabilities, airlines' pilot demands, and concerns of airlines and trainees with MPL system. Finally, three education and training measures on MPL application in Korea for the air navigation safety are suggested.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.2
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• pp.175-190
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• 2014

This study analyzes the business strategy of fast fashion through Zara, a successful fashion brand from Inditex Spain. An in-depth case approach is adopted based on extensive secondary research that includes literature and press releases published in Korean as well as English. The findings of this research demonstrate a speedy and flexible process occurring in the supply chain of its fast fashion business and the cooperation between the company's headquarters and international subsidiaries. Zara's headquarters executes four representative strategies: competitive market research, an integrated organizational structure, small quantity batch production, and a specialized distribution system. Zara's international subsidiaries execute their own four representative strategies: differentiated international expansion, independent human resource management, small but fundamental IT, and maximization of store resources. These two core parts intimately work together to satisfy target customers all over the world by bringing competitive advantages to the fashion business and represent a key concept of Zara's business strategy. The main drawbacks of case studies are limited validity and representativeness restraining the potential for making generalizations. However this case is considered sufficient to provide valuable insight and improve the understanding of operation strategy in fast fashion.

• Research in Community and Public Health Nursing
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• v.18 no.2
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• pp.266-275
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• 2007

Purpose: The purpose of this study was to evaluate achievements of a community health center for vulnerable population in urban areas and to find out its strength and weakness. Method: This evaluative study employed system theories and analytic techniques. Results: The purpose of improving vulnerable population's health-related self-care abilities adequately met the operation of programs. This center maintained close connection to a nursing college as a information resource. The subjects' satisfaction was high because team members who visited them were faithful and there were face-to-face contact, sufficient time set, closeness and resourcefulness. There were needs for regular meetings to discuss overall matters in organizing the program and to improve management skills. The mean score of health promotion lifestyle was 2.23 on a 4 point scale. This score indicates what in higher than vulnerable people in other communities. Conclusions: Community-based nursing centers for vulnerable population in urban areas should be developed as support organizations and community network.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.191-202
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• 2017

The purpose of this study is to develop an engineer competency model using Analytical Hierarchy Process (AHP) to improve the national technical qualification system. Korea has managed technical human resources at the government level through the operation of a national technical qualification system that certifies engineers with national certificates or technical grades by laws. However, there have been increasing concerns that the government system is separated from global standards and does not reflect an engineer's comprehensive capabilities. For these reasons, the new architecture of the system has been continuously discussed and becomes a major policy issue of the Korean government. For the development of the engineer competency model, domestic and global models were separately structured using 554 valid questionnaires with a consistency ratio (CR) of 0.1 or less. The relative importance of engineer competency factors in a domestic model was career (0.383), qualification (0.253), academic degree (0.195), and job training (0.169) whereas the order in the global model was career (0.308), global ability (0.237), job training (0.175), domestic qualification (0.147), and academic degree (0.134). The results of AHP analysis indicated that the evaluation factors and methods recognized by engineers were different from a current government model focusing on domestic qualifications. There was also perceptual difference in the importance of engineer evaluation factors between groups depending on the type of organizations and markets. This means that it is necessary to reflect the characteristics of organizations and markets when evaluating engineer competency. Based on AHP analysis and literature reviews, this paper discussed how to develop a new engineer competency index (ECI) and presented two effective index models verified by simulation test using 59,721 engineers' information. Lastly, the paper discussed major findings of our empirical research and proposed policy alternatives for the improvement of a national engineer qualification system. The paper contributes to the management of technical human resources since it provides quantitative competency models that are objectively developed by reflecting market recognition and can be effectively used by the policy makers or firms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.544-547
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• 2008

The Growth of Multimedia Digital Content market is extending to IP network environment. this is realized via IPTV service which provide Triple-Service that is broadcasting, communication, telephone service. Recently on IPTV Settop box has fixed key for control access permission. and this is cause of Wasting resource to operation and management. it can be resolved to apply DRM System which mixed MPEG-21 REL(Rights Expression Language) and XML Signature. In this paper, we designed Permission Management Module for IPTV Service which can control permission to access via MPEG-21 and XML Signature.

• Atmosphere
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• v.20 no.2
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• pp.173-186
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• 2010

The impact of the precipitation has been focused on losses in social and economical sectors. However, as growing the concerns of the future water shortage caused by the climate change, the precipitation should be consider in various views for an effective planning in the water resource management. A precipitation case occurred from 20 to 21 April 2009 was recorded as a welcome rain because it reduced the severe drought continued in Korea from winter season of 2008. In this study, economic values of the event was calculated with positive aspects in various sectors. The estimation is based on four major parts such as a secure of water resources, the improvement of air quality, the decrease of forest fires, and the reduction of the drought impact. The water resources only considered inflow waters into dams and the reservoirs managed by Korean public institutions and their economic values accounts for 5.92 billion won. Decreases of four air pollutants($PM_{10}$, $NO_2$, CO, and $SO_2$) were considered as the positive effects of the rainfall and estimated 175.4 billion won. The preventive effect of the forest fire after the rainfall results in 0.48 billion won. Finally, the rainfall during the drought period is effective to reduce the social costs of 108.65 billion won. Although the economic values estimated in this study explain parts of the positive effects of the precipitation, it can help to develop a comprehensive and systematic valuation system for the whole process of the precipitation. For doing this, various rainfall types should be analyzed in social-economic terms including economics, environments and hydrology.

• Journal of the Korean Society for information Management
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• v.26 no.1
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• pp.321-350
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• 2009

The purpose of this study is to find methods for utilizing digital room in public library and its efficient operation by analyzing the status quo of the digital rooms in public libraries, which had been built nation-widely about 5 years ago. It is found that it is urgent to supplement and improve the infrastructure of them. It is also required to build multi-functional digital rooms and an integrated operational system for digital rooms. Implementation of an integrated operational system, first of all, for applicable sections of digital room may be the best alternative. The multi-functional digital rooms can be built, which, in addition to its traditional function, can include a variety of original information resources and function of information creation using application programs, as well as functions such as education, information services, online/offline community creation, and activating information sharing. In the future, the digital rooms in public libraries must play a significant role as online/offline spaces, which are not the places for use and access to internet information resource, but for information/knowledge sharing and collaborative activities. It also must provide a communication channel between librarians and users as well as among users themselves.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.62-66
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• 2017

In this paper, we present the development of communication and data processing strategy for the electromagnetic wave precipitation gauge system. The electromagnetic wave precipitation gauge system is a small system for deriving area rainfall rates within 1 km radius through dual polarization radar observation at 24GHz band. It is necessary to take consider for measurement of accurate precipitation under limited computing resources originating from small systems and to minimize the use of network for the unattended operation and remote management. To overcome computational resource limitations, we adopted the fuzzy logic for quality control to eliminate non-precipitation echoes and developed the method by weighted synthesis of various rain rate fields using multiple radar QPE formulas. Also we have designed variable data packets rules to minimize the network traffic.

• Journal of Internet Computing and Services
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• v.13 no.3
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• pp.93-105
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• 2012

A data stream is a series of tuples which are generated in real-time, incessant, immense, and volatile manner. As new information technologies are actively emerging, stream processing methods are being needed to efficiently handle data streams. Especially, finding out an efficient evaluation for a multi-way join would make outstanding contributions toward improving the performance of a data stream management system because a join operation is one of the most resource-consuming operators for evaluating queries. In this paper, in order to evaluate efficiently a multi-way join continuous query, we propose a novel method to decrease the cost of a query by eliminating unsuccessful intermediate results. For this, we propose a matrix-based structure for monitoring data streams and estimate the number of final result tuples of the query and find out unsuccessful tuples by matrix multiplication operations. And then using these information, we process efficiently a multi-way join continuous query by filtering out the unsuccessful tuples in advance before actual evaluation of the query.