• Journal of the Korea Society for Simulation
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• v.15 no.3
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• pp.87-91
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• 2006

With the growth of the internet, the number of wireless internet users has increased continuously up to date. However, mobile communications could not support high speed transmission rate with cheap communication fee and wireless LAN has problems in providing terminal mobility and wide area connectivity, respectively. So the WMAN standard has been newly designed to make up for these limits. The initial 802.16 specification effectively offers a solution for providing fixed users with high speed wireless communication but it does not offer terminal mobility. So the 802.16d and 802.16e have been developed as the next generation solution that can support various PHY layer (SC, SCa, OFDM, OFDMA) and offer the terminal mobility. In this paper, we propose an effective uplink scheduling algorithm for VoIP with using UGS, and we show that our proposed algorithm is superior in view of average delay and management of uplink bandwidth to conventional rtPS algorithm and the scheme in reference, with using NS-2 network simulator.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.190-195
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• 2009

Since the industrial revolution, the global environmental problems such as greenhouse gas accumulation and the average temperature increase have caused people's attention. 'Low Carbon, Green Growth' was presented to cope with these global concerns, as one of main policies of 2008 in Korea. The paradigm of a green urban development is started to concern the whole city's energy problems owing to realize 'Low Carbon, Green Growth' in the urban side. The government established a nation's basic energy plan for 20 years, and some local cities made efforts to develop new renewable energy such as the solar, wind and water energy which are suitable to each city's character. As a part of these efforts, the concept of U-Eco city is newly appeared to reflect upon ubiquitous technique, urban ecology and the next generation energy system. However, urban plan is difficult to adopt this next generation energy system with existing laws, regulations and technical systems. The new executive and systematic system is needed to realize the U-Eco city U-Eco for the management of an efficient city. In this study, the authors investigate the concept of the next generation energy system and U-Eco city to realize the energy-efficient city plan and analyze problems to occur during the application of them in an existing city plan. Then, the authors show the remedies to deal with occurred problems.

• Nuclear Engineering and Technology
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• v.20 no.3
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• pp.189-196
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• 1988

This study investigates the effect of fuel pellet eccentricity on fuel rod thermal performance under the steady state condition. The governing equations in the fuel pellet and the cladding region are set up in 2-dimensional cylindrical coordinate (r, $\theta$) and are solved by finite element method. The angular-dependent heat transfer coefficient in the gap region is used in order to account for the asymmetry of gap width. Material propeties are used as a function of temperature and volumetric heat generation as a function of radial position. The results show the increase of maximum local heat flux at the cladding outer surface and the decrease of maximum and average fuel temperatures due to eccentricity. The former is expected to affect the uncertainties in the minimum DNBR calculation. The latter two are expected to reduce the possibility of fuel melting and the fuel stored energy. Also, the fuel pellet eccentricity introduces asymmetry in fuel pellet temperature and movement of the location of maximum fuel pellet temperature.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.153-161
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• 2008

Agriculture and forest are basis for livelihood in Nepal while both sectors constitute around 40 percent of the national product and over two-thirds of the economically active population is dependent on agriculture. However, radical changes in land use, depletion in crops production and food availability are major threats due to loss of soil fertilityand severe environmental degradation. In this study, we used time series data from 1986/87 to 2005/06 about food crop production and population published by Government of Nepal, Ministry of Agriculture and Cooperatives and Central Bureau of Statistics. Descriptive statistics and ArcGIS were used to assess and map the food security status of Nepalese Terai based on the local food demand and supply system. Food supply to demand ratio(FSDR) was the main idea of assessment. Our results showed that out of 20 districts, only 8 districts were categorised under secured food districts whereas 5 districts were still under food unsecured situation. The analysis further revealed that 7 districts had faced food deficit more than 8-16 times during the last 20 year periods. Data further showed that there was surplus food supply relative to the requirements dictated by FSDR. However, the average FSDR was less than 1.2(less than 20% surplus) exploring fact that most of the districts were not producing sufficient food to cope up the food shock and after 1995 it was relatively stagnant. Our prediction reveals that food supply in Terai even in the future would remain at almost the same level as now, and there will not more than 16-17% surplus by 2021 considering medium vibrant population growth. The findings thus, indicate that Terai may not be a food secure region in the future, even though the region is considered as a food storage house of Nepal. In addition, this paper suggests ways to make future comprehensive case studies more widely comparable in Terai, Nepal.

• Journal of Acupuncture Research
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• v.35 no.2
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• pp.95-100
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• 2018

Background: The aim of this study is to assess the feasibility of acupuncture treatment for the management of subacute and chronic post-thoracotomy pain in patients with traumatic multiple rib fractures. Methods: A total of 30 participants who have undergone thoracotomy after traumatic multiple rib fractures will be recruited. Participants will be invited and equally randomised into acupuncture plus usual care and usual care alone groups. A computer-generated random number sequence will be used and concealed using opaque, sealed, sequentially numbered envelopes. Twelve sessions of manual and electrical acupuncture performed by Korean medicine doctors will be provided over a span of 3 months to participants allocated to the acupuncture group. Participants in the usual care group will continue pain medication, exercise and physical therapy as required. Study feasibility will be measured based on the proportion of patients who complete the measurement of pain at 12 or 24 weeks after baseline. The clinical outcomes will include; the average pain intensity over the recent week at rest, movement and cough, quality of life, patient's global assessment of recovery, respiratory function measured by the pulmonary function test and use of pain medication at 4, 8, 12 and 24 weeks after enrolment. Adverse events will be recorded for all participants. Written informed consent will be obtained from all participants. The local ethics committee has approved the study. This pilot trial will inform further studies investigating the potential role of acupuncture for subacute and chronic post-thoracotomy pain in patients with traumatic multiple rib fractures.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.5
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• pp.299-303
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• 2009

Introduction: Maxillary malignant tumors are primary tumors of the maxillary gingiva, sinus, and palate. The purpose of this study was to research the prognosis and treatment modalities of maxillary malignant tumors. Materials & Methods: For this study, 52 patients, who were treated after being diagnosed for maxillary malignant tumors at the department of OMFS at Yonsei University college of Dentistry from January 1997 till April 2008, were classified, then the prognoses of these patients were evaluated depending on their primary site, histopathology and treatment modalities. The results of this study showed that the most common primary site for maxillary malignant tumors was the gingiva and for histopathology, squamous cell carcinoma. Result & Conclusion: The average follow up period was 32.7 months. In determining prognosis, the most important factors were the control of local site and metastasis of cervical lymph nodes. Therefore, for a better prognosis, a tumor free margin during surgery and a periodic follow up to examine for metastasis to cervical lymph nodes and other organs are necessary.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.611-620
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• 2014

This research analyzed the operation efficiency and influence factors of housing facilities for the severely disabled in Jeolla region by using the DEA model. First, the analysis of efficiency for 2012 was carried out using the CCR model. As a result, 12 DMUs were proved to be efficient, and the average efficiency of CCR was 0.85, confirming that the efficiency of all DMUs were satisfactory. Second, regression analysis was carried out to analyze the factors affecting the efficiency of the DEA model by using the Tobit model. In this case, the inputs and calculated variables were set as independent variables whereas the efficiency as the dependent variable. As a result, the detailed variables had a low significance; the overall input variables showed a negative influence while the calculated variables tended to be a positive influence. In terms of operation efficiency, there was no meaningful result in input variables besides the number of workers. Instead of expanding the input variables, the following should be made for housing facilities of the severely disabled; more efforts should be put in to improve welfare service delivery system and operating environment and structure, and the program must be supplemented as well.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.3
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• pp.114-128
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• 2013

Greenhouse gas emissions have been an important issue in different countries because of their effects on global warming. The government has to organize greenhouse gas reduction measures suitable to regional characteristics by establishing annual implementation plans and comprehensive policies based on the UNFCCC. The transportation sector is one of the major contributors of air pollution; hence increasing need to estimate current and future traffic emissions precisely. Under these circumstances, a number of emission models have been developed recently. However, current methods of estimation cannot carry out effective analyses because it does not reflect vehicle movement characteristics. This study aims to present a new method for calculating road traffic emissions in Goyang city. A travel demand model is utilized to carry out GHG emission estimates according the traffic data (fleet composition, vehicle kilometers travelled, traffic intensity, road type, emission factors and speed). This study evaluates two approaches to estimate the road traffic emissions in Goyang City: Pollution-Emis and the Handbook of Emission Factors for Road Transport (HBEFA v.3.1) which is representative of the "average speed" and the "traffic situation" model types. The evaluation of results shows that the proposed emission estimation method may be a good practice if vigilant implementation of model inputs is observed.

• Korean Journal of Adult Nursing
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• v.26 no.6
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• pp.693-702
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• 2014

Purpose: The purpose of this study was to examine the relationships between treatment belief, personal control, depressive mood, and health-related quality of life in patients with hemodialysis based on self-regulation theory. Methods: Data were collected from 220 patients at 27 local hemodialysis clinics in Seoul during 2013 and 2014. The Revised Illness Perception Questionnaire, the Hospital Anxiety and Depression Scale, and Medical Outcomes Study Short Form-12 were used to measure outcome variables. Data were analyzed using descriptive statistics, t-tests, ANOVA, Pearson correlation, and multiple regression using the 'enter' method. Results: Treatment belief and personal control scored 3.58 and 3.54 out of 5 points respectively, on average. Treatment belief and personal control of kidney disease were negatively correlated with depressive mood and positively correlated with health-related quality of life. According to the regression analysis, treatment belief, monthly income, and personal control were discovered to account for 21.8% of the variance in depressive mood, where as depressive mood, monthly income, treatment belief, and age were found out to account for 40.6% of the variance in health-related quality of life. Conclusion: Our study demonstrated significant positive relationships between treatment belief and illness outcome in hemodialysis patients. Interventions aimed to provide the necessary information and trust to maximize the effectiveness of treatment need be developed to improve patients outcomes.

• Journal of Environmental Science International
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• v.25 no.6
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• pp.865-875
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• 2016

In this study, mass concentrations and chemical compositions of $PM_{2.5}$, including water-soluble ions and elements were determined at the 1,100 m-highland of Mt. Hallasan in Jeju Island across four seasons from August 2013 to August 2014. The average mass concentration of $PM_{2.5}$ was $12.5{\pm}8.41{\mu}g/m^3$ with 45.8% of the contribution from eight water-soluble ionic species. Three ionic species ($SO{_4}^{2-}$, $NH{_4}^+$, and $NO{_3}^-$) comprised 96.2% of the total concentration of ions contained in $PM_{2.5}$ and were the dominant ions, accounting for 43.5% of the $PM_{2.5}$ mass at Mt. Hallasan. On the basis of the mass concentration level, seasonal variation, enrichment factor, and relationship among elements, we can presume that Mg, K, Ca, Mn, Fe, Co, Sr, Ba, Nd, and Dy originated mainly from crust or soil and that V, Cr, Ni, Cu, Zn, As, Cd, and Pb were significantly enriched in $PM_{2.5}$ owing to the effects of the anthropogenic emissions. These results and the local distribution of emission sources and topographic characteristics near this sampling site suggest that the compositions of $PM_{2.5}$ collected at the 1100 m-highland of Mt. Hallasan were largely influenced by inflow from outside of Jeju Island.