• Journal of Biomedical Engineering Research
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• v.33 no.3
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• pp.141-147
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• 2012

In this paper, we have investigated effects of two specific meditations (Chinese qigong meditation and Kundalini yoga meditation) on the heart rate variability (HRV), which is a well-known quantitative measure of autonomic balance, of skilled students. To analyze the effects, the MIT/BIH physionet database was utilized. The database includes RR intervals of eight skilled Chinese qigong meditators (5 women and 3 men; age range 26-35) and four skilled Kundalini yoga meditators (2 women and 2 men; age range 20-52). RR intervals of each subject were measured before and during the meditations. For HRV analysis, we have used typical four HRV parameters - the low frequency to high frequency power ratio (LF/HF ratio), SD2/SD1 ratio, sample entropy, and fractal dimension. The LF/HF ratio was calculated by the autoregressive spectrum and the SD2/SD1 ratio was derived from the Poincar$\grave{e}$ plot. The sample entropy was computed from the phase space plot and the fractal dimension was estimated by the Higuchi's algorithm. In the experiments, the Wilcoxon signed rank test was employed because we used small datasets and compared HRV parameters before and during the meditations. As a result, we have found increment of the LF/HF and SD2/SD1 ratios in both meditations; whereas the sample entropy is decreased during the meditations. In addition, the fractal dimension is increased during the Chinese qigong meditation; whereas it is decreased during the Kundalini yoga meditation. The results show that the sympathetic nervous system is generally more activated in skilled Chinese qigong and Kundalini yoga meditators, but the activation of the parasympathetic nervous tone is suppressed.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.428-430
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• 2012

Korea View 는 지상파 디지털 TV 의 새로운 서비스 프레임워크로 6MHz 의 지상파 방송 대역폭 내에서 하나의 HD 채널만 서비스되던 것을 향상된 비디오 압축 기술을 이용하여 1 개의 HD 채널과 3 개의 SD 채널, 총 4 개의 채널을 서비스하는 지상파 다채널 디지털 TV 서비스를 의미한다. 본 논문에서는 Korea View 서비스 프레임워크에 H.264/SVC 를 이용하여 SD 급으로 전송되던 3 개의 채널에 대해 SVC 의 공간 계위를 갖도록 부호화 한 HD 급 향상계층 비디오 부호화 스트림을 광대역 망을 통해 전송하는 다채널 하이브리드 HDTV 방송서비스 프레임워크를 제안하고 이를 위해 H.264/SVC 의 부호화 성능을 평가하고 분석한다. 이를 위해 본 논문에서는 H.264/SVC 기본계층에 해당하는 3 개의 SD 채널에 대해 1.5Mbps 목표 비트율로 부호화 하는 동시에 H.264/SVC 의 향상계층에 해당하는 HD 비디오의 부호화를 수행하여 SD 급 기본계층과 HD 급 향상계층의 부호화 성능을 평가 및 분석하였다. 실험을 통해 SD 급 기본계층에서 34.5dB 이상의 화질로 서비스 가능한 수준의 객관적 화질임을 확인하였고, HD 급 향상계층에 대해서는 12Mbps 비트율로 부호화 된 MPEG-2 영상의 화질을 제공하기 위해 690kbps 이상의 비트율이 필요하다는 것을 제시한다.

• Korean System Dynamics Review
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• v.11 no.2
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• pp.45-75
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• 2010

Today, the logistics industry has played a critical role in national economy activities. The low cost and high efficiency of the logistics industry are meaningful in the improvement of national competitiveness and the logistics industry. However, efficiency of logistics is lower than that of the United States and Japan since most quantities are processed in road transportation in Korea. With regard to this, existing studies expected a saving of social and environmental costs due to a decrease of road transportation as well as improvement of logistics productivity due to bulk transportation through activation of rail and costal transport. For the expectation, the existing multimodal transport systems should be improved first. Therefore it aimed to develop scenario-based simulation models of multimodal transport systems for decision makers in charge of improvement in the logistics area. For model development, this study utilized Thinking Process and System Dynamics(TP-SD) methodology.

• Korean System Dynamics Review
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• v.4 no.2
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• pp.95-130
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• 2003

The purpose of this study is to find what causes make public projects hold off, going beyond the planned deadline and budget. Using System Dynamics(SD) and their derivative Urban Dynamics(UD) models, it intends to analyze major feedback loops based on VENSIM and to simulate them with STELLA software, all of which are interrelated with various causes of project delay. To prevent or ameliorate project delay, first of all it advises to focus on endogenous delaying factors not exogenous ones. These factors either reinforce or balance certain loops in complex causal structure, In the case example on the Cremation Building Project in Cheongju, Residents’ participation demand make negotiation put off and delayed negotiation reinforces administrative-expediency planning in order to observe a time limit, on the other hand, once building consensus, it increase both the level of planning performance and public trust. In the meantime, the real planning process used to neglect residents opinions and manage public grievance only through compensation, he a result of simulation, visible fruit of negotiation in the initial phase seems to be not satisfactory owing to funds and time consumed, but after reaching an mutual agreement among stakeholders, planning performance is effective and strategic than administrative-expediency planning viewed in both financial and time angle. It proposes to devise specific tools schematizing project implementation. In order to upgrade the quality of project management, it recommends for planners to adopt key concepts based on SD/UD diagrams and causal loops, which would contribute to enriching Planning abbots.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.3
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• pp.93-114
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• 2002

This paper suggests a dynamic balanced scorecard (DBSC) model employing the concept of system dynamics (SD), which could overcome the limitations inherent in the conventional balanced scorecard (BSC) and facilitate strategic learning process in organizations. The BSC has been a successful framework for measuring an organization＇s performance in various Perspectives through translating an organization＇s vision and strategy into an interrelated set of key performance indicators and specific actions. The BSC, while having significant strengths over traditional performance measurement methods, however, has its own limitations, due to its static nature, such as overlooking two-way causation between performance Indicators and neglecting the impact of delayed feedback flowing from the adoption of new strategies or policy changes. To overcome these limitations, we employs SD, a methodology for understanding complex systems where dynamic feedback among the interrelated system components significantly impact on the system outcomes. The SD simulation model in the form of DBSC we suggest in this paper would serve as a useful strategic learning tool for facilitating an organization＇s communication process through various scenario analyses as well as predicting the dynamic behavior pattern of their key performance measures over a future time frame. For the demonstration purpose, we apply the DBSC model to Korea Coal Corporation (KoCoal ) BSC case.

• Journal of Technologic Dentistry
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• v.30 no.2
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• pp.105-119
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• 2008

This study explored the status of free time activities among the dental technicians who are working at Seoul, Gyonggido, and Gangwondo. On the basis of this research, we aim to present needs and applicable solutions to improve the working conditions and enhance the quality of life through more effective time management in free time activities that lead to their self development and far more enriched life. 500 subjects were randomly chosen and the questionary sheets were provided. Among them, 305 sheets were returned to be analysed through SPSS Win 10.0 software and the results are as follows; First, mean in the satisfaction of leisure activities was 3.44(SD=.73). Mean in sub categories was as follows; psychological factor(M=3.65, SD=.71), social factor(M=3.54, SD=.75), rest factors(M=3.52, SD=.63), physical factor(M=3.43, SD=.88), other factors(M=3.40, SD=.66), circumstantial factor(M=3.33, SD=.63), educational factor(M=3.24, SD=.73). Second, the most relevant sub categories in the satisfaction of leisure activities were social, educational, physical, and other circumstantial factors by sequence. Factors that affect leisure activities satisfaction were career and status of health, which shows statistical significance(p<.001). That is to say, contention of this study is that the general characteristics are closely related with and affect the types and the level of satisfaction in leisure activities of the subjects. Considering these results, the dental businesses and the associations of dental technicians should recognize the needs to improve the time management through more efficient cooperations between dentists and back office dental team, systemized working time, and introduction of incentive system among others. On the basis of this appreciation, the dental business should provide more time and various opportunities with the dental technicians. Dental technicians also need to reconsider their appreciations of leisure activities, that is, leisure activities are not just spending time doing something but they refresh them and enable them to be more active and faithful to home and work.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.600-604
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• 2007

In this study, we first prepared 3 kinds of powders with different molecular masses from the crude protein-bound polysaccharide extract of Agraricus blazei Murill through ultrafiltration, followed by spray-drying. Then, the antitumor activities of the powders were analyzed. Size exclusion chromatography coupled with a multi-angle laser-light-scattering system showed the 3 powders had the following molecular ranges: below 10 kDa (SD-1), 10 to 150 kDa (SD-2), and above 150 kDa (SD-3), representing peak molecular weights of $8.26{\times}10^3,\;9.65{\times}10^4$, and $5.94{\times}10^6\;g/mol$, respectively. All the powders stimulated macrophage RAW264.7 cells to produce nitric oxide, of which SD-2 and SD-3 were superior to the crude extract powder (CP-SD), while SD-1 showed the lowest activity. Similar results were found for their cytotoxicities against human cancer cell lines (A549, MCF-7, and AGS), where the highest activity was obtained with the SD-2 treatment for 72 hr at $1,000\;{\mu}g/mL$. The MCF-7 cell line was less sensitive to the powders than the other cells. From this research we found that ultrafiltration, in combination with spray-drying, is applicable for preparing protein-bound polysaccharide powders with higher antitumor activities.

• The Korea Journal of Herbology
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• v.34 no.5
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• pp.29-37
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• 2019

Objectives : Bang-poong (Saposhnikovia divaricata; SD) was traditionally used to treat inflammatory disorders. In this study, we aimed to investigate whether Bang-poong and related species including SD, Glehnia littoralis (GL), and Peucedanum japonicum (PJ) possess neuroprotective effects and acetylcholinesterase (AChE) inhibitory activities. Methods : Roots of SD, GL and PJ were extracted with distilled water (DW) or 70% ethanol (EtOH). We assessed 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activities of the extracts. To examine neuroprotective effects, we measured cell viability in PC12 or HT22 cells after treatment of the extracts with $H_2O_2$ or amyloid-beta ($A{\beta}$). To assess anti-neuroinflammatory effects, we measured the nitric oxide (NO) levels after treatment with the extracts and lipopolysaccharide (LPS) in BV2 microglial cells. In addition, we performed AChE inhibition assay to explore effects of the extracts on the cholinergic system. Results : DW and EtOH extracts of SD, GL and PJ showed mild DPPH free radical scavenging activities. Also, DW extracts of GL and PJ showed protective effects against $H_2O_2$-induced toxicity in PC12 cells. In LPS-activated BV2 cells, EtOH extracts of SD, GL and PJ exerted inhibitory effects on NO production. Meanwhile, DW extracts of SD, GL and PJ inhibited the $A{\beta}$-induced cell death in HT22 cells. In addition, DW and EtOH extracts of GL exhibited remarkable inhibitory activities on AChE. Conclusions : We demonstrated that SD, GL and PJ exert anti-oxidative, anti-neuroinflammatory and AChE inhibitory activities. These results indicate that SD, GL and PJ could be potential candidates for neurological disorders.

• Journal of Korea Water Resources Association
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• v.45 no.1
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• pp.101-111
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• 2012

In this paper, the feedback loop mechanisms among the operational indices and exogenous variables of a sewerage system that are inherent in the operation and maintenance of a sewerage system were identified using the System Dynamics (SD) modeling methodology. The identified feedback loops were used to develop a SD computer simulation model that can be used to predict future operational conditions of a sewerage system and identified the efficient ways of operation. The data of Busan metropolitan city sewerage system was applied to verify the developed SD model and predict future operational conditions of the system. As a result, it was predicted that sewage treatment efficiency, volume of sewage treatment and cost recovery rate will be gradually increased, whereas service rate which was already very close to the target will remain almost the same as the current value. Furthermore, sensitivity analysis concerning some operational indices was performed in order to discover the policy leverage. As a result, it was found that the exogenous variables related to the pipe maintenance had a great effect on facility using rate, volume of sewage treatment as well as sewage treatment efficiency.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.773-774
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• 2006

Devices which coupled in network environment should be operated in various service-oriented ways by several services. In this paper, we propose service-oriented application architecture which based on OSGi. OSGi is very well defined industrial standard by using platform independent technology.