• Journal of IKEEE
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• v.19 no.4
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• pp.491-499
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• 2015

Silicon Carbide(SiC) has large advantage in high temperature and high voltage applications because of its high thermal conductivity and large band gap energy. When using SiC to design power semiconductor devices, edge termination techniques have to be adjusted for its maximum breakdown voltage characteristics. Many edge termination techniques have been proposed, and the most appropriate technique for SiC device is Junction Termination Extension(JTE). In this paper, the change of breakdown voltage efficiency ratio according to the change of doping concentration and passivation oxide charge of each JTE techniques is demonstrated. As a result, the maximum breakdown voltage ratio of Single Zone JTE(SZ-JTE), Double Zone JTE(DZ-JTE), Multiple Floating Zone JTE(MFZ-JTE), and Space Modulated JTE(SM-JTE) is 98.24%, 99.02%, 98.98%, 99.22% each. MFZ-JTE has the smallest and SZ-JTE has the largest sensitivity of breakdown voltage ratios according to the change of JTE doping concentration. Additionally the degradation of breakdown voltage due to the passivation oxide charge is analyzed, and the sensitivity is largest in SZ-JTE and smallest in MFZ-JTE, too. In this paper, DZ-JTE and SM-JTE is the best efficiency JTE techniques than MFZ-JTE which needs large doping concentration in short JTE width.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.147-156
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• 2011

Though a dozen of different software life cycle models are suggested, there is no universal model which can satisfy all the characteristics of software. Organizations mix and match different life cycle models to develop a model more tailored for their systems and capabilities. We suggest overlapped-concurrent development life cycle model that is more suitable in various software development environment. Firstly, we divided the development process into abstract and implementation stage. Abstract stage is from software concept phase to detailed design starting time, and implementation stage is from detailed design phase to system testing phase. Next, the abstract stage introduced the overlapped phase concept that begins the next phase when the step is completed 20% by applying pareto's law. In the implementation stage, we introduced the concurrent development which the several phases are performed some time as when one use-case (UC) is completed the next development phase is started immediately. The proposed model has an advantage that it can reduce the inefficiency of development resource greatly. This model can increase the customer satisfaction with a great product at a low cost and on a short schedule. Also, this model can contribute to increase the software development success rate.

• Korean Journal of Childcare and Education
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• v.7 no.2
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• pp.181-203
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• 2011

The purposes of this study were to examine the perception of directors and child care providers regarding the Seoul-type Child Care Accreditation and its operating system. The objects were 309 directors and child care providers at accredited Seoul-type child care centers. The collected data was analyzed using frequency, percentiles, and ${\chi}^2$. The results are as follows: First, the majority of directors and child care providers perceived 'the preparation for effective quality control of child-care service' as the primary purpose of the Seoul-type Child Care Accreditation. Many of them responded that the child care centers meeting the purpose of accreditation would be 'private' and 'home-based' ones. Seoul-type Child Care Accreditation was easier to pass compared to National Child Care Accreditation. The directors and child care providers perceived that the accreditation will narrow the gap between public and private child care centers. Second, in operating customized child-care service, most directors preferred 'submits only the same plan as that of a designated one', but most child care providers preferred 'assessment after providing customized child-care'. For the reliable child-care service and accounting management system, both subject groups showed general satisfaction with 'current system'. Third, both subject groups responded that 'overtime pay for child care providers' and 'government's consistent child-care policy' were what they desire most to improve Seoul-type Child Care Accreditation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.5
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• pp.237-242
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• 2010

Magnesium-substituted BCP (biphasic calcium phosphate) powders were prepared by incorporating small amounts of magnesium into the structure of different hydroxyapatite (HAp)/${\beta}$-tricalcium phosphate (${\beta}$-TCP) ratios through coprecipitation method. A series of magnesium substitutions ranging from 0, 0.5, and 1.0 wt%, which are comparable to the measured magnesium contents, were performed. The obtained powders were characterized by the following analytical techniques: X-ray diffraction analysis (XRD), Thermo Gravimetric Analyzer (TGA) and Fourier transform infrared spectroscopy (FT-IR). The results have shown that substitution of magnesium in the calcium-deficient apatites resulted in the formation of biphasic mixtures of different HAP/${\beta}$-TCP ratios after heating above $1000^{\circ}C$. The 1.0 wt% magnesiumsubstituted-BCP were soaked in Hank's solutions after 2 weeks to observe the morphology of the biocement, especially needle-like hydroxyapatite crystals and to estimate the length and diameter of nanoneedle crystals.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.5
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• pp.201-208
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• 2016

Ceramic pigments, which show good thermal and chemical stabilities, have been applied for various industry with development of digital printing technology. Ceramic inkjet printing has advantages of high efficiency of ink usage and eco-friendly process. Thus, the interest of the ceramic pigments with various function and color including CMYK (cyan, magenta, yellow, black) digital primary color is increasing. Here, we investigated the thermal and chemical stabilities of white ceramic pigment for digital inkjet printing process. The microstructure and crystal structure of MgO, $Al_2O_3$, $MgAl_2O_4$, $CeO_2$ were analyzed, and the stability with glaze were evaluated. In order to evaluate the applicability for digital inkjet printing, the chemical stability of white ceramic pigments at high temperature was investigated by characterization of the mixed color properties with CMYK ceramic pigments after firing process.

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.3
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• pp.99-106
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• 2002

The application method of GIS for planning of forest road network can be save the efforts and cost by frequently change of forest road and evaluation the forest road route before construction. The purpose of this study is to suggest the proper method for planning an optimal forest road network in mountains forest using geographic information system(GIS) in the national forest of Mt. Kumsan at Namhae-gun, Gyungsangnam-do. In the forest road network planning by the minimum longitudinal gradient, The total length was 20.41km, and road density was 6.92m/ha. In the forest road network planning by mixed with the minimum longitudinal gradient and the maximization of investment effect, The total length was 21.15km, and road density was higher than that of the minimum longitudinal gradient as 7.17m/ha. The road length overlapped by cost path was more short than 3.52m/ha of the minimum longitudinal gradient as 1.73km. So, it appeared that forest road has an high effectiveness in yarding function. Therefore, it considered that the geographic information system could provide an effective and resonable solutions for planning of optimal forest road network.

• Journal of Digital Contents Society
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• v.9 no.3
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• pp.399-412
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• 2008

The 21st century has been changed into a knowledge-oriented society, which means our society is more dependent on information and moves toward information. The mixing of broadcasting and co mmunication prevails and it makes possible a new type of broadcasting service. Depending on that, a broadcasting is being changed into a consumer-oriented service to satisfy the demands of consum ers in a new media age. It makes us attain to the personal media age to be possible interactive com munication unlike existing one-way transmission. As a result, new complex media are commercialize d and the instance is DMB. DMB is said 'my own TV' or 'TV in my own hands'. But it has limit t o retransmit existing broadcast programs. So hereafter, DMB broadcasting must be produced with co ntents suited its properties out of retransmitting existing contents. It is necessary to analyze exactly properties and service fields of DMB media to make an establish production direction of contents for DMB. This paper intends to suggest overall optimized image-contents production direction including appropriate program developments, a proper running time, visual expressions such as a camera angle and walking etc... DMB contents suited with its properties will give more familiarities to DMB users. Besides, DMB is expected to be a new culture watching broadcasting.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.1
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• pp.91-101
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• 2008

Structural analysis models to develop live load distribution factors of simply supported prestressed concrete I-girder bridge should have the precision of the analysis results as well as modeling simplicity. This is due to the numerous frequency of structural analysis needed while developing live load distribution factors. In this study, an appropriate structural analysis model is selected by comparing previous researchs studies and models used in practical design. Also, the influence by the flexural stiffness of barrier and diaphragm on the live load distribution had been analyzed through comparing the numerical analysis and experimental tests. As a result, the model that the eccentric girder and the barrier and diaphragm are connected to the deck plate was appropriate in satisfying both accuracy and simplicity for structural analysis of simply supported prestressed concrete I-girder bridge. However, the barrier was analyzed to have insignificant influence on the live load distribution in spite of its variation of stiffness. The eccentric diaphragm showed little influence at 25% or higher of flexural stiffness. From the results, a model that the girder is rigidly connected to the deck plate in consideration of the eccentricity, the barrier is ignored and the whole section of diaphragm is supposed to be valid without eccentricity is decided as the most appropriate structural model to develop the live load distribution factors of simply supported prestressed concrete I-girder bridge in this study.

• Korean Journal of Social Welfare
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• v.63 no.1
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• pp.267-289
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• 2011

The purpose of the present study was to develop a Korean version of the scale of attitudes for disabled Persons and attitudes towards disabled person-original by translating and modifying the scale proposed by Antonak(1982). In order to test validation, this study was focused on processing survey and statistic data analysis and tried to find a way to applicate in Korea. The data were collected from 500 non-disabled persons divided into two groups, which were consist of target group (public officials, health care providers, teachers, journalists and rehabilitation facility staffs) and general group. Based on the descriptive analysis, exploratory factor analysis and confirmatory factor analysis of the data, validity and reliability were examined. Also to find the statistic significant difference on attitudes towards disabled person between target group and general group, t-test was proceed. The result of the exploratory factor analysis drew 15 items representing 3 factors (Pessimism-Stereotype, Optimism-Human Rights, Derogatory Personality Stereotype). A confirmatory factor analysis results provided the construct validity of this scale as good and reasonable fitness. Cronbach's alpha ranged from .67 to .85 showed internal consistencies of the sub-scales. The subscales were significantly correlated with convergent with DFS(Disability Factor Scale) variables. And the target group had more positive attitudes toward disabled person than general group. It is suggested this scale more suitable for various disability types be elaborated, and get a practical implication on attitudes towards disabled person.

• Korean Journal of Social Welfare
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• v.69 no.2
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• pp.271-294
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• 2017

Social workers empathized with clients'distress, feel concerned for clients in distress, and try to reduce their distress. This is called compassion. Compassion is an essential component of social work practice. However, compassion results in both positive results and negative results. The purpose of this study is to evaluate the Korean version of ProQOL which was developed to measure compassion satisfaction and compassion fatigue of helping professionals, to identify levels of compassion satisfaction/fatigue of the participants, and to divide the participants into clusters by clustering variables which are compassion satisfaction/fatigue. A total of 284 social workers residing in Seoul and Surrounding areas participated in this study. Confirmatory factor analysis confirmed that the Korea version of ProQOL is composed of compassion satisfaction factor and compassion fatigue factor as reported in a previous study. Its reliability and validity were satisfactory. The level of participants'compassion satisfaction was above moderate and their level of compassion fatigue was below moderate. Those who are older, have graduate education, have more years of work experience, or have higher positions have more compassion satisfaction. Cluster analysis divided the participants into 3 clusters. Cluster 1 is characterized by moderate compassion satisfaction and low compassion fatigue, Cluster 2 is characterized by low compassion satisfaction and moderate compassion fatigue, and Cluster 3 is characterized by high compassion satisfaction and high compassion fatigue.