• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2469-2490
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• 2019

A low-energy adaptive clustering hierarchy (LEACH) protocol is a low-power adaptive cluster routing protocol which was proposed by MIT's Chandrakasan for sensor networks. In the LEACH protocol, the selection mode of cluster-head nodes is a random selection of cycles, which may result in uneven distribution of nodal energy and reduce the lifetime of the entire network. Hence, we propose a new selection method to enhance the lifetime of network, in this selection function, the energy consumed between nodes in the clusters and the power consumed by the transfer between the cluster head and the base station are considered at the same time. Meanwhile, the improved FTBA algorithm integrating the curve strategy is proposed to enhance local and global search capabilities. Then we combine the improved BA with LEACH, and use the intelligent algorithm to select the cluster head. Experiment results show that the improved BA has stronger optimization ability than other optimization algorithms, which the method we proposed (FTBA-TC-LEACH) is superior than the LEACH and LEACH with standard BA (SBA-LEACH). The FTBA-TC-LEACH can obviously reduce network energy consumption and enhance the lifetime of wireless sensor networks (WSNs).

• Radiation Oncology Journal
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• 제38권2호
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• pp.138-147
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• 2020

Purpose: To evaluate the dosimetric variations in patients of head and neck cancer treated with definitive or adjuvant radiotherapy using optimized non-coplanar (ncVMAT) beams with coplanar (cVMAT) beams using volumetric arc therapy. Materials and Methods: Twenty-two patients of head and neck cancer that had received radiotherapy using VMAT in our department were retrospectively analyzed. Each of the patients was planned using coplanar and non-coplanar orientations using an optimized couch angle and fluences. We analyzed the Conformity Index (C_IRTOG), Dose Homogeneity Index (DHI), Heterogeneity Index (HI_RTOG), low dose volume, target and organs-at-risk coverage in both the plans without changing planning optimization parameters. Results: The prescription dose ranged from 60 Gy to 70 Gy. Using ncVMAT, C_IRTOG, DHI and HI_RTOG, and tumor coverage (ID_95%) had improved, low dose spillage volume in the body V_5Gy was increased and V_10Gy was reduced. Integral dose and intensity-modulated radiation therapy factor had increased in ncVMAT. In the case of non-coplanar beam arrangements, maximum dose (D_max) of right and left humeral head were reduced significantly whereas apex of the right and left lung mean dose were increased. Conclusion: The use of ncVMAT produced better target coverage and sparing of the shoulder and soft tissue of the neck as well as the critical organ compared with the cVMAT in patients of head and neck malignancy.

• 대한간호학회지
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• 제22권2호
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• pp.127-142
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• 1992

The purpose of this study was to identify relationships between the nursing performance of staff nurses and the leadership styles of head as perceived by the head nurses and the staff nurses. The subject consisted of 33 head nurses and 200 staff nurses who were working at SNUH between July 1, and July 31, 1991. Leadership styles as perceived by head nurses and staff nurses were measured using an instrument adapted by Park (1988) . Evaluations of the nursing performance of staff nurses were done by head nurses utilizing a questionnaire adopted by Park(1988). Data were analysed using percentage distribution, ANOVA, Scheffe test and Pearson Correlation Coefficient. The results are summarized as follows : 1. The majority of the head nurses and staff nurses perceived the head nurse as having a tendency to exercise high level authority and benevolence oriented leadership. 2. The majority of the staff nurses carried out their nursing performance in a highly skilled manner. 3. There were significant differences in perceptions of leadership style between head nurses and staff nurses. 4. “Authority” and “Benevolence” in leadership style as perceived by the head nurses were related very weakly to the nursing performance of the staff nurse. 5. “Benevolence” of leadership style as perceived by the staff nurses was related very weakly to the nursing performance of the staff nurse. 6. Group comparisons of nursing performance and leadership style found that high nursing performance by the staff nurse was related in the group with high “Authority” as perceived by the head nurse and low “Authority” as perceived by the staff nurse. From the above findings, this study suggests the following : 1) Further studies are needed to control extraneous variables. 2) Efforts in leadership development are needed to enhance nursing performance. 3) Factor exploration study are needed to seek factors that contribute to the perception gap between the head nurse and the staff nurse.

• 대한예방한의학회지
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• 제18권1호
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• pp.43-52
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• 2014

This study was conducted to analyze if there is a difference between the head hospital and branch hospital by comparing the profitability and operating expenses to patient revenue of oriental medicine hospitals affiliated with universities in order to find whether opening branch hospitals is an appropriate method to increase profitability. Profit indices used for the comparison of head hospital and branch hospital include ratio of operating profit on medical revenue, net-income on medical revenue, net profit to total assets, and operating profit to total assets; and cost indices included ratio of labor costs, material costs and administrative costs. In comparison of profit indices of head hospitals and branch hospitals, head hospitals displayed negative(-) in all four profit index averages while branch hospitals displayed positive(+), showing that branch hospitals have higher profitability. In particular, in the case of head hospitals, ratio of net profit to total assets was -13.6%, while that of branch hospitals was 12.9%, which was higher than 3.1%, the average of Korean oriental medicine hospitals in 2011. As a result of difference analysis between groups of head hospitals and branch hospitals, profit indices of ratio of operating profit on medical revenue, net-income on medical revenue, and ratio of net profit to total assets were found to vary by hospitals, but there was no statistically significant difference between head hospitals and branch hospitals(p<0.1). Only the ratio of operating profit to total assets of head hospitals and branch hospitals indicated significant difference between the two groups, showing that ratio of operating profit to total assets of branch hospitals is larger than that of head hospitals. Meanwhile, the cost indices of ratio of labor costs, material costs and administrative costs in the difference test results did not show significant difference between the head hospital and branch hospital(p<0.1). Thus, it cannot be said that a certain oriental medicine hospital's profitability is high or low depending on whether it is head hospital or a branch as profitability varies depending on the management environment of the hospital. Therefore, oriental medicine hospitals affiliated with universities would need to make efforts to increase their profitability as an individual hospital rather than focusing on whether they are head hospital or a branch.

• 한국생산제조학회지
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• 제22권6호
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• pp.937-944
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• 2013

This paper describes an improved model that can be used for configuring a non-contact pneumatic head to handle a large sheet of glass. The cylindrical head model is of a large size (70 mm). It operates on vortex flow, which can simultaneously generate suction and repulsion over the flat object's surface. The head allows for the minimal non-contact lifting of objects weighing over 3N by using reference conditions (working pressure and head dimensions). Additionally, a functional flow-guide is applied for inducing a developing tangential vortex flow to increase suction and repulsion to the reference head. The cylindrical flow-guide is associated with relatively low tangential velocity. The improved model generates greater lifting force than the reference model, as verified experimentally.

• 한국토양비료학회지
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• 제45권5호
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• pp.717-724
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• 2012

Salt accumulated soil should be reclaimed to lower salt level for crop production. This study was carried out to investigate the characteristics of water flow and transport of mono and divalent solutes on salt accumulated soils with different head pressures. Saturated hydraulic conductivity was measured by constant and falling head methods with maintaining different head pressures. Saturated hydraulic conductivity was influenced by bulk density and organic matter contents in soils, but it had different elusion patterns between saline and sodic soil. While the quantity of water necessary for reclamation could be varies with soil type, it was considered that the supply of one pore volume of water was affordable and economic. Additional head pressure significantly increased the volume of leachate at a given time and it was more effective at low organic matter soils. The results indicate that additional head pressure would be one of the best irrigation practices on desalination method for salt accumulated soils.

• Radiation Oncology Journal
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• 제17권3호
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• pp.179-187
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• 1999

치료선량의 증가와 주위 정상조직의 보호의 의미에서 근접치료의 효과는 입증되어 있다. 그러나 우리 나라에서는 아직 통상치료법으로 상용화가 되어 있지 않다. 저자는 저선량률 이리디움 근접조사치료의 임상적 경험을 바탕으로 두경부암에서의 근접조사치료의 역사, 사용되는 동위원소의 재원 및 특성, 시행 시 고려 하여야할 사항, 임상기술적인 문제, 방사선물리학적 문제 등을 검토하였고 저자의 임상 경험 185례의 치료성적을 분석하여 그 효과를 검증하였고 마지막으로 향후 발전방향을 제시하여 보았다.

• 대한두경부종양학회지
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• 제38권1호
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• pp.25-29
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• 2022

Parathyroid carcinoma is very rare malignant neoplasm, accounting for less than 0.005% of all cancers. Most parathyroid carcinoma is a functioning tumor that causes hyperparathyroidism, leading to hypercalcemia. We report a parathyroid carcinoma case that was suspicious for spontaneous infarction of cancer, leading to resolution of hypercalcemia. A 29-year-old male visited our hospital presenting with right neck swelling and pain. He has been experiencing frequent urolithiasis for four years but laboratory tests showed normal serum calcium level. Right vocal cord paresis was identified with laryngoscopy. Ultrasonography revealed a 3.7 × 3.5 cm mass in the right thyroid containing a focal cystic portion. Computed tomography confirmed the presence of a low-density right thyroid mass. Right thyroid lobectomy was performed and pathological evaluation revealed parathyroid carcinoma with central necrosis. We report this very rare case with a literature review.

• 한국인터넷방송통신학회논문지
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• 제16권3호
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• pp.129-135
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• 2016

저시력인들을 위한 기존 시각 향상 장치들이 많이 있다. 이 장치는 주로 확대경 역할이 대부분이고, 고가이다. 저시력 원인으로는 다양한 증상에 기인한다. 시력 향상을 위해서는 영상의 확대, 밝기, 대비를 조절할 필요가 있다. 따라서 시력 향상 휴대용 마이크로 디스플레이 구동 드라이버 및 장치를 개발한다. 이 장치의 4가지 기본 원리는 영상 확대, 특정 색 조절, BLU로 밝기 조절, 프리즘에 의한 시축 개선이다. 제안된 HMVED 장치의 임상 실험이 실시되었다. 결과적으로 기존 장치에 비해서 수혜 효과가 돋보였으며 본 장치는 저중량, 저가, 휴대성이 용이하므로 저시력인의 삶의 질 향상에 도모한다.

• 한국유체기계학회 논문집
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• 제15권3호
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• pp.32-38
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• 2012

This paper is aimed to propose the design database(DB) of the inline micro-turbine for 5kW class. CFD analysis is performed to investigate the effect of a turbine on each parameter. This study showed that RadhaKrishna's data is different from the 5kW class in the low-head and the micro-turbine. Therefore, new DB for the design of inline micro-turbine for 5kW class could be needed. This study configured new design DB for the design of inline micro-turbine for 5kW class. The DB of this study showed that the optimal hub ratio(Dp/DR), the optimal body ratio(Db/DR) and the optimal range of body length ratio(Lh/DR) is 50%, 1.1 and 2.3 to 2.9, respectively.