• 한국노년학
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• v.32 no.2
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• pp.649-668
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• 2012

The purpose of this study ahead of the aging society in Korea to prevent problems of the elderly aged new addiction Internet Addiction and identify factors affecting the quantitative increase and qualitative improvement beyond that aims to promote. To this end, residents in Seoul over the age of 60's targets, local welfare, cultural centers, senior centers and other research in the area through one-on-one interviews were conducted the survey. Findings The average degree of Internet addiction elderly 36.16 points (SD = 10.02) and the distribution of at least 20 points to 65 points, respectively. Factors affecting the degree of Internet addiction as a computer time (β = .248, p <.001), mon allowance (β = .180, p <.01), age (β = .139, p <.01) and social support (β = .087, p <.05), self-efficacy (β = - .078, p <.05), most used location (β = - .116, p <.05), degree of family relationship (β = - .147, p <.01), housing type (β = - .153, p <.01), were of the order, this factor was 17.6% of the variance. In other words, the more computer time, the higher the age, the more mon allowance, housing is not self, the lower the degree of family relationship, the house is not a place most used, lower self-efficacy, social support is high As increasing the degree of Internet addiction was thought to be the two predictor variables. Survey results to target the elderly through the Internet addiction group psychotherapy program implementation, and production and distribution of manuals related to Internet use and addiction-related factors, according to the case-by-case Case management services are tailored to be done, and the Internet in general for seniors potential risks related to use in training and preventive services for the elderly will need to be made.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.3
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• pp.206-211
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• 2018

Purpose: Recently, a method of forming a slot in the prosthesis lingual has been introduced to solve the occlusal and aesthetic disadvantages of screw-retained prosthesis in the manufacture of implant-fixed prosthesis and to ensure retrievability in cement retained prostheses. The purpose of this study is to investigate the effect of the internal gap on the removal of the prosthesis in the preparation of cement-retained implant prostheses with lingual slots. Materials and methods: Titanium abutment and internal gap of the zirconia prosthesis to be attached to the upper part were set to 30, 35, and $50{\mu}m$, respectively. Three for each type total 15 were produced for each type. The zirconia prosthesis formed a retrievable cement-type slot with a space of 1 mm at the location where the titanium abutment meets the shelf area. Autocatalytic resin cement was used for bonding of abutment and zirconia prosthesis, and the maximum removal stress value was measured in units of Ncm by using the customized equipment of the cemented specimen. The Kruskal-Wallis test was used to compare the three groups by statistical analysis (${\alpha}=.05$), modified by post hoc test the Mann-Whitney U-test and the Bonferroni correction method were used to compare the two methods (${\alpha}=.017$). Results: There was no statistically significant difference in removal stress between the $30{\mu}m$ group and the $35{\mu}m$ group in the internal gap (P = .032), and there was a significant difference between the $30{\mu}m$ group and the $50{\mu}m$ group, between the $35{\mu}m$ group and the $50{\mu}m$ group (P < .017). Conclusion: Thus, the internal gap of computer-aided design affected the retention between the zirconia prosthesis and the titanium abutment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.1844-1849
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• 2014

Existing measurement methods using microscopes or surface roughness measurement instruments for surface control in manufacturing die are low in their efficiency when they are applied in industrial fields due to structural problems. Therefore, it is very important to develop a measurement and analysis system which can enhance efficiency in the measurement of different-sized manufacturing dies and provide quality control regardless of location. This study aimed at the development of a portable surface measurement system to satisfy this need. This measurement system was designed and manufactured in such a way as to divide it into three parts: the Base, the Body, and the Optical system. As a result of testing the system, the surface roughness was measured with an accuracy between 94.9 and 99.9%, and the deviation in the measurement value of a circle was within $2{\mu}m$.

• Korean journal of communication and information
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• v.51
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• pp.65-86
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• 2010

This paper reviews the problems and opportunities of Japanese newspaper industry. In the focus are particularly issues related to causes of the crisis and reacting strategies overcoming the crisis. To answer the questions, we conducted in-depth interviews with top-level managers of major newspaper companies in Japan. Secondary data were gathered to complement the interview. Top managers mainly perceived the causes of the crisis as young readers' alienation from newspaper due to the change of media environment and structural factors such as increasing production/distribution costs and diminishing appeals for advertisers. They are implementing several strategies to overcome this crisis - developing newspaper content for young readers; packaging customized on-off line advertisement; extending news distribution via online and mobile platforms; diversifying business into diverse sectors such as real-estate; enhancing brand equity of newspaper; and collaborating with rival newspaper companies in operating news site and joint printing/distribution. Lessons from the case of Japanese newspaper industry may be useful starting points for the Korean newspaper companies agonizing for diminishing circulation and advertising revenues.

• Journal of Korean Home Economics Education Association
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• v.25 no.1
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• pp.155-172
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• 2013

This study developed smart education programs on clothing in Home Economics education for middle school students and assessed the validity of the programs. To create a self-directed adaptive learning model, 'Textile fibers' was selected as a topic. A digital textbook was developed to provide an adaptive learning experience to each student. The students can learn the contents of the digital textbook via their smart phones or tablet PCs in their Home Economics classes. To create a cooperative learning model for a good communication, 'Recycling clothes' was selected as a topic. Students can cooperate to solve the problems via Google docs and facebook in their Home Economics classes. The programs gained more than 4.5 on a 5-point Likert scale. The results of the assessment indicated that the smart education programs on clothing are appropriate to enhancing the self-directed learning, communication, and cooperation competencies of the students in Home Economics classes.

• Journal of Convergence for Information Technology
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• v.9 no.7
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• pp.106-113
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• 2019

The purpose of this paper is aimed to derive suggestions for convergence technology for effective management of distance education by analyzing a long-term case. The experiment was designed with notebook, smartphone or tablet based robot controlled by a remote instructor and a learner, who have experience of distance learning including robot assisted learning. The tablet based robot has the display system of feedback to speakers. During five months, three types of experiments were conducted randomly and a participant was interviewed thoroughly. The result, like the previous research, demonstrates that the task performance of the learner in telepresence robot-assisted learning was better than that in the notebook, and smartphone based. However, it is believed to be necessary to adjust the system for eye-contact and voice transmission for the remote instructor. The instructor required an additional sight by supplementing an extra camera and automatic direction control to source of sound.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.4
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• pp.324-332
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• 2011

Purpose: The purpose of this study was to compare the stress distribution of teeth and jaw on load by differentiating property of materials according to each layer of widely used mouthguard. Materials and methods: A Korean adult having normal cranium and mandible was selected to examine. A customized mouthguard was constructed by use of DRUFOMAT plate and DRUFOMAT-TE/-SQ of Dreve Co. according to Signature Mouthguard system. The cranium was scanned by means of computed tomography with 1mm interval. It was modeled with CANTIBio BIONIX/Body Builder program and simulated and interpreted using Alter HyperMesh program. The mouthguard was classified as follows according to the layers. (1) soft guard (Bioplast)(SG) (2) hard guard (Duran)(HG) (3) medium guard (Drufomat)(MG) (4) soft layer + hard layer (SG + HG) (5) hard layer + soft layer (HG + SG) (6) soft layer + hard layer + soft layer (SG + HG + SG) (7) hard layer + soft layer + hard layer (HG + SG + HG) The impact locations on mandible were gnathion, the center of inferior border, and the anterior edge of gonial angle. And the impact directions were oblique ($45^{\circ}$). The impact load was 800 N for 0.1 sec. The stress distribution was measured at maxillary teeth, TMJ and maxilla. The statistics were conducted using Repeated ANOVA and in case of difference, Duncan test was used as post analysis. Results: In teeth and maxilla, the mouthguard contacting soft layer of mandibular teeth presented lowest stress measure and, in contrast, in condyle, the mouthguard contacting hard layer of mandibular teeth presented lowest stress measure. Conclusion: For all impact directions, soft layer + hard layer + soft layer, the mouthguard with three layers which the hard layer is sandwiched between two soft layers, showed relatively even distribution of stress in impact.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.641-649
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• 2023

This study compares and analyzes the performance of a shield manufactured using 3D printing technology to find out its applicability as a shield in high-energy electron beam therapy. Actual measurement and monte carlo simulations were performed to evaluate the shielding performance of 3D printing materials for high-energy electron beams. First, in order to secure reliability for the simulation, a source term evaluation was conducted by referring to the IAEA's TRS-398 recommendation. Second, to analyze the shielding performance of PLA+W (93%), a specimen was manufactured using a 3D printer, and the shielding rate by thickness according to electron beam energy was evaluated. Third, the shielding thickness required for electron beam treatment was calculated through a comparative analysis of shielding performance between PLA+W (93%) and existing shielding bodies. First, as a result of the evaluation of the source term through actual measurement and simulation, the TRS-398 recommendation was satisfied with an error of less than 1%, thereby securing the reliability of the simulation. Second, as a result of the shielding performance analysis for PLA+W (93%), 6 MeV electron beams showed a shielding rate of more than 95% at 3.12 mm, and 15 MeV electron beams showed a shielding rate of more than 90% at 10 mm thickness. Third, through simulations, comparative analysis between PLA+W (93%) materials and existing shields showed high shielding rates within the same thickness in the order of tungsten, lead, copper, PLA+W (93%), and aluminum. 6 MeV electron beams showed almost similar shielding rates at 5 mm or more and 15 MeV electron beams. Through this study in the future, it is judged that it can be used as basic data for the production and application of shielding bodies using PLA+W (93%) materials in high-energy electron beam treatment.

• 대한공업교육학회지
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• v.40 no.2
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• pp.130-154
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• 2015

The purpose of this study was to analyze the mechanical and metallurgical education (MME) teachers' job using the Developing a Curriculum (DACUM) methodology. To accomplish the purpose of this study, an MME teachers' job/occupational analysis was conducted in the following steps: "Planning the DACUM workshop," "Recruiting/Constructing the DACUM committee members," "Providing the DACUM orientation," "Holding the DACUM workshop," "Verifying the DACUM result," and "Refining the DACUM chart based on verification data." The DACUM job/occupational analysis was conducted by fifteen DACUM committee members in the DACUM workshop in January, 2015; moreover, the DACUM chart of the MME teachers was verified by the group of subject matter experts. The major findings of the study were as follows. First, this study defined the MME teachers who taught mechanical and metallurgical-related subjects to students with the secondary education teacher certification and performed work related to character education, career guidance, life guidance, and others in a specialized high school, the Meister high school. Second, this study determined 16 duties and 199 tasks for fulfilling the MME teachers' job; moreover, the study extracted the importance, difficulty, and frequency of each task and demand for the entry-level workforce. Third, this study provides the DACUM research chart based on the job/occupational analysis results of the MME teachers.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.227-227
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• 2012

Cryopump는 반도체 임플란타 공정, OLED분야, 신소재 개발, 표면분석 및 처리, 의료분야, 입자가속기, 핵융합 등 다양한 진공분야에 응용되는 고진공용 극저온펌프이다. 특히 향후로의 산업구조는 디스플레이, 반도체, IT 산업분야로 집중 재편될 것이기에, 이에 따른 핵심제조장비인 고진공 펌프의 수요가 급증할 것으로 판단된다. 그리고 이를 위한 핵심부품과 장비들의 국산화가 시급한 실정이다. 기술적인 측면에서 보자면 GVT는 미국의 Varian과 일본Ebara의 Cryopump 제조기술을 원천으로 한 회사로써 현재는 국내 유일의 G-M냉동기와 Cryopump 제조기술을 보유한 업체이다. 그리고 최근 오랫동안 정체되었던 관련 기술을 발전시켜 최적화된 한국형 G-M 냉동기 및 이를 장착한 다양한 사이즈의 고성능 Cryopump를 출시하게 되었다. 가장 큰 수확은 Cryopump의 성능을 크게 향상시켰으며 무엇보다 고객맞춤형으로 디자인할 수 있을 정도의 기술력을 확보하게 되었다는 점이다. Cryopump의 성능은 장착되는 Cryocooler(G-M냉동기)의 성능과 밀접한 관련이 있기 때문에 일차로 Cryocooler의 성능을 개선하고 이차로 이를 장착한 Cryopump의 성능을 개선하였다. 본 연구는 일차로 진행된 HP Series 2단 Cryocooler 4가지 모델 중 가장 범용인 HPM 모델과 HPS모델에 대한 제작과 성능시험에 관한 것이다. 이는 각각 기존의 ICP Series 펌프에 장착되던 Expander 535 모델 및 Expander 855 모델에 대한 설계 최적화의 결과물로써 내용은 Cryocooler에 대한 'Typical Performance Test(1st STG와 2nd STG의 온도가 각각의 Stage에 인가되는 Heat Load에 의해 그물망 형태의 그래프가 되도록 수행하는 시험법)'의 절차를 따라 수행되었다. HPM Cryocooler의 성능은 2nd STG Temp. 20K 와 1st STG Temp. 80K를 Heat Load 기준으로 하였을 경우, 각각 8.2W, 55.0W의 성능을 나타내었고 HPS Cryocooler의 성능은 2nd STG Temp. 20K 와 1st STG Temp. 72K를 Heat Load기준으로 하였을 경우, 각각 14.0W, 90.0W의 성능을 나타내었다. 1st STG Temp.를 72K로 정한 이유는 Power Supply의 용량 한계로 인해 90W이상의 Heat Load를 인가할 수 없었기 때문이다. 만약 성능 그래프의 경향성을 고려하여 1st STG Temp. 80K로 가정한다면, 각각 약 13W, 100W 정도의 성능을 가질 것으로 추정된다. 단, 본 시험에 사용된 Compressor는 GVT의 HC80Plus 모델로 내부에는 Helium용 5HP급 Scroll Type의 Compressor가 장착되어 있으며, 봉입압력 250Psig에 저압 100Psig기준, 65scfm의 유량을 가지는 압축기이다. 압축기와 Cryocooler의 조합은 1:1이었고 시험방법은 Cryocooler에 대한 GVT 자체규정에 따라 진행되었으며 밤과 낮 및 공장전체의 부하변동에 따른 냉각수 온도변화에 따른 펌프의 성능변화는 고려되지 않았다.