• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.47-53
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• 2012

In general, it is essential that contents are to be provided with proper bitrate according to network conditions in order to support higher quality of video streaming services over wired and wireless networks. Recently, DASH is adopted by the MPEG as the standard for HTTP based adaptive streaming technology and consists of the server and clients. The clients should parse XML files from the server and play contents after accessing the finely divided segments into various bitrates. In this paper, we designed a Smart AP(Access Point) which exists between DASH contents server and Non-DASH clients enables provide DASH services to Non-DASH clients. In addition, proposed Smart AP provides DASH service to various types of clients as maintaining the existing environment without additional development costs.

• Journal of Broadcast Engineering
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• v.22 no.5
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• pp.548-559
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• 2017

Recently, various high-quality AV services such as UHDTV have begun to increase as broadcasting technology evolves, and various broadcasting standards have been defined. Among the various broadcasting standards, there are representative delivery technologies which are DASH/ROUTE and MMTP. DASH/ROUTE and MMTP are adopted as delivery standards for UHD broadcasting in south Korea, currently. DASH segment and MPU are segmented units including media data, which are delivered via DASH/ROUTE and MMTP, respectively. In this paper, we analyzed structure of DASH segment and MPU and propose a verification system which enables converting DASH segments to MPUs and delivering them via MMTP.

• Journal of Korean Biological Nursing Science
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• v.12 no.3
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• pp.195-205
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• 2010

Purpose: The purpose of this study was to develop the dietary approaches to stop hypertension (DASH) diet education program tailored to Korean adults and to examine the effect of the DASH diet education program on bone mineral density in middle aged women. Methods: The subjects of this study were 26 middle aged women, pre and post menopause, who attend a church located in Kyung-In district. The DASH group I (n=13) was provided with the DASH diet education program only, while the DASH group II (n=13) was provided with DASH diet education program along with calcium supplements (1 g/day). The DASH diet education program included one lecture on DASH diet, one face to face counseling, and five telephone counseling sessions during the 8 weeks period. Results: The knowledge and subjective compliance level of DASH diet increased significantly in both groups, at 4 and 8 weeks after the intervention. The level of objective compliance of DASH diet in both groups increased over the study period, but it was not significant as compared to those of the baseline. Bone mineral density of both groups decreased at 8weeks as compared to the baseline after the intervention. Conclusion: Although 8weeks of DASH diet education program increased the knowledge and compliance of DASH diet, it was not effective to bring the changes in bone mineral density among the middle aged women.

• Journal of KIISE
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• v.42 no.8
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• pp.1039-1048
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• 2015

Recently, the web-based adaptive streaming service, DASH (Dynamic Adaptive Streaming over HTTP), is receiving more attention. However, existing network-based and buffer-based video quality control schemes in DASH environments make oscillation of segment throughput, causing degradation of the quality of experience (QoE) with frequent quality changes and playback interruptions because these schemes do not consider the content characteristics. In this paper, we propose a C-DASH (Content Characteristics based Dynamic Adaptive Streaming over HTTP) scheme in order to improve the QoE in DASH environments. The C-DASH scheme performs seamless and smooth quality control based on the segment throughput, buffer status, and segment size of the content. Based on simulation results, it is confirmed that the C-DASH scheme can improve the QoE, when compared with the existing quality control schemes.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.2
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• pp.156-169
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• 2009

In this study, the authors introduced DASH (Disabilities of the arm, shoulder, and hand), which had been developed for evaluating the functional impairment in the movement of upper extremities in regular daily activities, work ability and sports/performing arts ability. It is an ergonomic risk assessment tool used for industrial workers and also a disability measurement tool for upper extremity disorders arising from musculoskeletal disorders and symptom. This study intended to examine the applicability of DASH in occupational health field. Firstly, DASH development process and composition were reviewed through The DASH outcome measure user's manual and early articles. Secondly, reliability, validity, and responsiveness of the DASH in various languages at the application stage as well as its reliability and validity at the early stage of development were investigated. Thirdly, focusing on the application of DASH to clinical cases, workers with musculoskeletal symptoms, healthy workers, workers with other diseases, and general population were discussed besides workers with major musculoskeletal disorders. Lastly, DASH questionnaire was examined for its potential as a reference for assessing the functional impairment in the movement of upper extremities of workers with musculoskeletal symptoms in industrial workers in Korea.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.18-21
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• 2018

최근 시청자에게 실재적인 몰입감을 제공하는 실감미디어가 발전하고 있다. 이러한 실감미디어 중 가장 접근성이 뛰어난 것은 VR으로, 현재 다양한 서비스에 응용되고 있는 상황이다. 하지만 360VR은 높은 비트 전송률과 고해상도의 특성을 지니고 있기 때문에 대역폭 비용 및 시청자의 QoE 보장의 불확실성 등의 다양한 문제가 있다. 이러한 문제를 개선시키기 위해 HTTP 기반의 적응적 스트리밍 기법이 발전해나가고 있으며 이 기술의 표준으로 MPEG-DASH가 채택되었다. MPEG-DASH는 TCP 기반의 전송 프로토콜을 사용하고 있지만 현재 TCP는 고용량의 데이터가 전송되는 웹 기반에서 HTTP의 병목현상을 일으켜 대역폭 효율성을 떨어뜨리는 하나의 원인으로 나타나고 있다. 이러한 문제를 해결하기 위해 본 논문에서는 UDP 기반의 QUIC 프로토콜을 MPEG-DASH에 적용하는 시스템을 고안하고 이를 QUIC-DASH라 칭한다. 고해상도의 360VR 송출 실험으로 QUIC-DASH 시스템과 기존의 MPEG-DASH 시스템을 비교 분석한 결과로 대역폭의 절감이 이루어진 것을 확인하였다.

• Journal of Korean Biological Nursing Science
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• v.19 no.3
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• pp.141-150
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• 2017

Purpose: The purpose of this study was to investigate the effects of the Korean Dietary Approaches to Stop Hypertension (DASH) education program on oxidative stress, antioxidant capacity, and serum homocysteine (Hcy) level in elderly Korean women. Methods: This was a quasi-experimental study employing non-equivalent control group pretest-posttest design. The DASH group (n= 27) underwent the DASH education program for 12 weeks, whereas the control group (n= 21) was provided one education session. The survey was conducted before and after the intervention period. Results: In DASH group, monounsaturated fatty acid (MUFA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) intakes significantly increased after the intervention as compared to prior to the intervention. No significant differences were found in the control group. After the intervention, thiobarbituric acid reactive substance (TBARS) and Hcy levels significantly decreased in the DASH group but not in the control group. Conclusion: The DASH education program was effective in reducing oxidative stress and Hcy levels in elderly Korean women.

• Journal of The Korean Association For Science Education
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• v.23 no.4
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• pp.386-400
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• 2003

This paper presents an analysis of the Developmental Approaches in Science, Health and Technology (DASH) program, a K-6 curriculum developed by the Curriculum Research & Development Group (CRDG) at the University of Hawaii employing the curriculum analysis framework created by Posner. Using this framework the analyst found that the DASH design is based on the research on learning, teaching, and assessment now driving efforts to reform science education at the elementary level. DASH embraces the constructivist idea that learning is a personal and social process and the recapitulation model that new concepts are built out of theories previously learned. DASH provides an understandable, exciting, and memorable experience in the operations of science, health, and technology, and develops their capacity to use the skills and knowledge of science, health, and technology both in and outside school. A number of studies of DASH have examined its functionality, effectiveness of pedagogy and what students learn. The innovative nature of DASH necessitated a multidimensional assessment that included both quantitative and qualitative research techniques. Ongoing development of the DASH program in the research setting of a university laboratory school permits ever deeper connections with emerging curriculum theory and curriculum practice, and allows new linkages as ideas are tested in research classrooms.

• KIISE Transactions on Computing Practices
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• v.21 no.1
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• pp.82-87
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• 2015

There are many current researches that are looking to improve the quality of HTTP adaptive streaming services. However, the existing schemes have a serious problem of QoE (Quality of Experience) degradation because few consider VBR video transmission. To cope with this problem, in this paper, we proposed a novel media quality adaptation scheme called CB-DASH (Content and Buffer-aware DASH). The proposed scheme controlled the video quality considering the VBR characteristics of video and the client's buffer state. Through the simulation, we proved that our scheme accomplished a more accurate estimated bandwidth than the conventional DASH and improved the QoE of streaming service.

• Journal of KIISE
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• v.44 no.4
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• pp.423-432
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• 2017

Recently, the video quality control schemes for the improvement of the QoE (Quality of Experience) of video streaming services that are based on DASH (Dynamic Adaptive Streaming over HTTP), which is a standard of HTTP adaptive streaming (HAS) services, have been studied. However, the problem of the existing schemes is the degradation that is due to unnecessary quality changes because the VBR (Variable Bitrate) characteristics of the video are not considered. In this paper, we propose a SC-DASH (Segment Characteristics-based DASH) which controls the video quality based on the segment characteristics. The SC-DASH can prevent the occurrence of the unnecessary quality changes by controlling the video quality based on the size of the next segment, the segment throughput, and the buffer occupancy. The experiment results showed that the SC-DASH improves the QoE by reducing the unnecessary quality changes compared with the existing quality control schemes.