• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1B
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• pp.51-59
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• 2011

It is the background that the provision of the mobile WiMAX femtocell trial service of a leading mobile telecommunication service operator using small base stations for indoor mobile broadband services and coverage expansion through eliminations of shadow areas in this paper. The paper presents an analysis result of trial subscribers' usage satisfaction for the mobile WiMAX femtocell service and suggests a market approach strategy of a mobile WiMAX femtocell service based on the analysis result. The interesting influence factors are extracted from wide influence factors suggested by existing research literature related with mobile service usage satisfaction and confined to a system quality, a service quality, and an account structure with consideration for attributes of mobile WiMAX femtocell service under exploring its early stages of service market. And then we analyze impacts of the factors to the mobile WiMAX femtocell service usage satisfaction. As a result, a system quality and an account structure have a tendency to provide considerable impacts to subscribers' usage satisfaction for mobile WiMAX femtocell service which is immature in both its technology and market. Therefore a market approach with the preferential consideration of the two factors will be valid.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.94-100
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• 2002

This paper is concerned with the development, and performance test of LIPCA (Lightweight Piezo-composite Curved Actuator) that is lighter than other conventional piezo-composite type actuators. LIPCA is composed of top fiber composite layers with a high modulus and low CTE (Coefficient of Thermal Expansion), a middle PZT cermaic wafer, and base layers with a high modulus and high CTE. The performance of each actuator was evaluated using an actuator test system consisting of an actuator supporting jig, a high voltage actuating power supplier, and a non-contact laser measuring system. The simply supported condition actuator was excited by the power supplier with 1.0Hz cycle and up to $100\sim400V_{pp}$. The displacement at the center point of actuator was measured with non-contact laser displacement measuring system, It has been shown that the LIPCA-C2 can 34% decrease in mass and 13% increase in displacement compared to THUNDER.

• Archives of Plastic Surgery
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• v.32 no.1
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• pp.29-36
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• 2005

Craniosynostosis is the premature fusion of one or more sutures of either cranial vault or base. Fused sutures may impede normal growth of the calvaria, leading to characteristic skull deformities; Morphological craniosynostosis is classified descriptively. Being craniosynostosis uncorrected the deformity progresses continuously and causes an increase of intracranial pressure. The surgical involvement aims at the expansion of intracranial space as well as satisfactory achievement of craniofacial shape. Early surgical correction in infancy prevents the deformity from the further progression and possible associated complication of high intracranial pressure. A long period of follow-up is essential to asses the outcome of an effectiveness of the surgery. measurement of intracranial volume has been concerned in medical personnel and anthropologists for many years. A reliable and accurate measurements of the intracranial volume facilitates to make a diagnosis and treatment of craniosynostosis. Pre-and postoperative change of intracranial volume was evaluated with 3D CT scanning in 12 cases of craniosynostosis who underwent frontal advancement and total cranial vault remodeling. Increased intracranial volume is attributed to surgical release of craniosynostosis and natural growth. We conceive that the intracranial volume is significantly increased after surgical correction of fused cranial sutures and along with natural growing. A procedure of frontal advancement and total cranial vault remodeling is very useful to correct such a deformity as craniosynostosis. And also 2 cases out of five mentally retarded patients improved remarkably and Forehead retrusion or temporal depression followed in another two cases.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.5
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• pp.22-28
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• 2008

This paper aims to offer a solution based on semantic document classification to improve e-Government utilization and efficiency for people using their own information retrieval system and linguistic expression. Generally, semantic document classification method is an approach that classifies documents based on the diverse relationships between keywords in a document without fully describing hierarchial concepts between keywords. Our approach considers the deep meanings within the context of the document and radically enhances the information retrieval performance. Concept Weight Document Classification(CoWDC) method, which goes beyond using existing keyword and simple thesaurus/ontology methods by fully considering the concept hierarchy of various concepts is proposed, experimented, and evaluated. With the recognition that in order to verify the superiority of the semantic retrieval technology through test results of the CoWDC and efficiently integrate it into the e-Government, creation of a thesaurus, management of the operating system, expansion of the knowledge base and improvements in search service and accuracy at the national level were needed.

• International Journal of Automotive Technology
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• v.5 no.1
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• pp.55-59
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• 2004

Spot welding is a very important and useful technology in fabrication of thin sheet structures such as the parts in an automobile. However, because the fatigue strength of the spot welding point is considerably lower than that of the base metal due to stress concentration at the nugget edge, the nugget size must be estimated to evaluate a reasonable fatigue strength at a spot welded lap joint. So far, many investigators have experimentally studied the estimation of fatigue strengths of various spot weldments by using a destructive method. However, these destructive methods poses problems so testing of weldments by these methods are difficult. Furthermore, these methods cannot be applied to a real product, and are time and cost consuming, as well. Therefore, there has been a strong, continual demand for the development of a nondestructive method for estimating nugget size. In this study, the effective nugget size in spot weldments have been analyzed by using thermoelastic stress analysis adopting infrared thermography. Using the results of the temperature distribution obtained by analysis of the infared stress due to adiabatic heat expansion under sinusoidal wave stresses, the effective nugget size in spot welded specimens were estimated. To examine the evaluated effective nugget size in spot weldments, it was compared with the results of microstructure observation from a 5％ Nital etching test.

• The Journal of the Korea Contents Association
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• v.17 no.1
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• pp.728-739
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• 2017

This study has a purpose that comes up with a practical direction of training program about a cultivating vocational competence to older adults for living an independent life including a social, economic, and emotional base. The aged people suffered from a employment uncertainty because the aged people's job opportunity is just opened to unskilled works and not related with a regular lifelong educational program. In this study, the direction of program for cultivating vocational competence should be expanded and standardized. Also, there are less social agreement about older adult's cultivating vocational competence has a meaning above the purpose with economic activity. And the program should related with the employment. The direction of program for cultivating vocational competence to older adult should be the expansion and standardization of program. and should have the opportunity of sympathy about older adult's physical and social problem.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.2
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• pp.59-69
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• 2013

By the end of 2012, there were 5.1 billion mobile communication subscribers in South Korea. The majority of subscriptions (97.3 percent) were for mobile phones, particularly smartphones. From 2010 to 2012, the number of mobile phone subscriptions increased 2,000 percent, growing from an initial subscriber base of 150 million. This paper explores the changing mobile communication landscape from a socio-technological perspective to understand the underlying drivers of change and their effects on the South Korean populace. A content analysis of 11,156 electronic newspaper articles mentioning mobile communication in South Korea and occurring between 2010 and 2012 was conducted. 5,119 keywords were extracted based on frequency statistics and further analyzed to determine the drivers of change. Based on this analysis, we conclude that South Korea's mobile communication environment is focused on rapid expansion of technology with minor consideration given to the social aspects of this change. This has resulted in several negative consequences and we urge for new policies by government and industry to address this gap.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.1022-1027
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• 1999

This paper proposes method that uses Time-Difference-of-Arrival(TDOA) of Forward Pilot signals from base stations(BS) arriving at a mobile station(MS) as a position location method of CDMA MS. MS searcher does acquisition of BS Pilot signals and measurement of TDOAs. In order to do it, its processing gain is very important. Proportional relationship of the gain to the signal coherent integration interval is theoretically derived and analyzed and field test is performed to show acquisition of weak Pilot signals and stable measurements of TDOA values by increasing the gain. Also, signal strength decrease exponentially by the distance it travels. Therefore, improvement of the searcher gain makes possible to acquire Pilot signals at a location far away from BS. Variation of possible position estimation area relative to the signal strength within a cell is simulated with computer. Neglecting shadow effect it indicated necessity of detecting signals below -35dB in order to cover over 90% of cell area. Thus, efforts to maximize searcher coherent integration interval in order to acquire weak Pilot signals are required for expansion of position estimation area and measurement of stable TDOA values.

• Hwankyungkyoyuk
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• v.18 no.3 s.28
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• pp.75-90
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• 2005

The purpose of this study was to analyze middle school students' consumption lifestyle and develop a program for measuring Ecological Footprint (EF) for them. For this study, 200 male and female middle school students in large cities, medium & small cities were selected to analyze their consumption lifestyle. It was also that the existing programs for measuring EF were studied and basic rules of setting up new EF indicators were established based on the results of survey and literature study. 15 indexes was selected by dividing the life areas into food, housing, traffic, goods and services areas and than the delpi computer programming tools was used to develop program for measuring EF in this study. The program for measuring EF can be used as educational materials for consumers' environment education in the areas of social environment education and school environment education. The followings are suggestions coming out of this study. First, it is required to revise and complement program for measuring EF analyzing the problems that occur when applying it to middle school students actually. Second, some data that used during normalization of EF ate originally from the USA. So it is necessary to change the data to meet the Korean situation. Third, it is necessary to have design work that can invite interests of students with consumers' environmental education materials through cooperation between environmental education experts and computer programmers. Fourth, it is necessary to have practical research with consumers' environmental education adding educational contents into EF measurement program. Fifth, it is necessary to develop a method for distribution an expansion of the program for measuring EF to make it usable in different types of environmental education materials.

• The Research Journal of the Costume Culture
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• v.18 no.5
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• pp.1003-1016
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• 2010

The purpose of this study is to reorganize any rusty image including natural modeling characteristic presented from the natural phenomenon to certain patterns in order to create the fashion design that are valued in the expansion of independently expressional area and modeling art. As a method for research, the author analyzed the concept and characteristic for rust with a base of theoretical background by the documental research and realistic consideration, analyzed its modeling characteristic through domestic and overseas pictures, and e-documents as data, inspected the modeling activities of various categories that various images were adapted related to rust, looked into the concept of Digital Textile Printing and its producing procedure as an expressional method, and analyzed the examples of modern dress and its ornament making use of Digital Textile Printing. The conclusions of this study are as below. First, the rust occurred due to the natural phenomenon is the bond with different material like metal, each unique modeling characteristic occurs and harmony of various patterns has abundant aesthetic value. Second, the author could endowed sensible characteristic and speciality with works and could produce creative fashion design that painting, abstractive pattern and harmony of unique sense of colors are significant by using the image of rust, Third, to emphasize natural feeling of rust, the author could develop creative design that simple silhouette and impressive pattern look significant by reorganizing and applying rust according to repetition, increment, rhythm, contract, emphasis and harmony. Fourth, Digital Textile Printing method is used to induce visual effect by the expression of feels of rust, and the author could express the natural patterns, delicate expression for the feels of a material and unique design of emotion.