• Archives of Plastic Surgery
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• 제32권5호
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• pp.567-572
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• 2005

An electrical burn used to result in the damage of the skin and underlying deep soft tissue injury. Thus, in order to preserve devitalizing tissues and promote the structural survival free flaps with ample blood supply are frequently employed. However, early unpredictable vascular injury and progressive tissue necrosis may cause the free flaps full of hazards. We applied 50 free flaps upon 41 acute electrical burn cases between 1998 and 2004. Injured areas, timing of operation and causes of flap loss were studied. The victim's ages ranged from 13 to 60 years. (an average 37.8 years) Thirteen out of 50 free flaps were lost totally: three cases were due to arterial insufficiency and ten venous congestion. Total loss of flaps were observed in 5 of 12 cases in the postoperative 3 weeks, 6 of 20 cases between 3 and 6 weeks and 2 of 18 cases after 6 weeks. In three of 12 cases the free flap was lost partially in the postoperative 3 weeks, 4 of 20 cases between 3 and 6 weeks and 1 of 18 cases after 6 weeks. The result was statistically significant by a T-test (p<0.05). This study showed that timing of the operation is accountable for the loss of free flap. It is most important to conduct the free flap procedure on an electrical injury at the time when the recipient vessel is definitely discernible and intact so as to minimize the loss of flap and spare the structures.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권4호
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• pp.720-740
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• 2011

Wi-Fi-enabled portable devices have recently been introduced into the consumer electronics market. These devices download or upload content, from or to a host machine, such as a personal computer, a laptop, a home gateway, or a media server. This paper investigates the fairness among multiple Wi-Fi-enabled portable devices in a home network when they are simultaneously communicated with the host machine. First, we present that, a simple IEEE 802.11-based home network suffers from unfairness, and the fairness is exaggerated by the wireless link errors. This unfairness is due to the asymmetric response of the TCP to data-packet loss and to acknowledgment-packet loss, and the wireless link errors that occur in the proximity of any node; the errors affect other wireless devices through the interaction at the interface queue of the home gateway. We propose a QoS-provisioning framework in order to achieve per-device fairness and service differentiation. For this purpose, we introduce the medium access price, which denotes an aggregate value of network-wide traffic load, per-device link usage, and per-device link error rate. We implemented the proposed framework in the ns-2 simulator, and carried out a simulation study to evaluate its performance with respect to fairness, service differentiation, loss and delay. The simulation results indicate that the proposed method enforces the per-device fairness, regardless of the number of devices present and regardless of the level of wireless link errors; furthermore it achieves high link utilization with only a small amount of frame losses.

• 한국터널지하공간학회 논문집
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• 제16권1호
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• pp.75-89
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• 2014

최근 세계 여러 나라에서는 지하공간의 활용이 증가하고 있다. 특히, 저심도 굴착의 경우 대부분 개착식 굴착공법을 적용하는데, 극심한 교통 체증 및 인접구조물의 불안정 등의 문제가 발생될 수도 있다. 이러한 문제를 극복하기 위해서 저토피 토사구간에서 충분한 안정성을 확보하고 공사기간을 최소화하며 터널을 굴착할 수 있는 M-CAM공법(Modified Cellular Arch Method)이 제안되었다. 본 연구에서는 M-CAM공법 적용 시 주열식 수직연속벽체(Continuous Pile Wall, CPW)의 규격 및 지반조건이 터널 거동에 미치는 영향을 파악하기 위해 민감도분석을 수행하였다. 우선 터널의 안정성에 영향을 주는 매개변수로는 수직연속벽체의 근입깊이, 직경, 측압계수 그리고 지반상태를 선정하였다. 한편 수치해석을 위해서, 유한차분법에 기초를 둔 FLAC 2D가 이용되었다. 본 연구결과 수직연속벽체의 규격 중 근입깊이가 터널 안정성에 가장 큰 영향을 주는 것을 확인되었다.

• 전기학회논문지
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• 제65권4호
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• pp.555-560
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• 2016

Recently, many countries have placed great attention on energy security and climate changes. Governments are promoting the construction of renewable energy projects with regulatory support in Korea. Despite an increasing penetration of renewable resources, however, the photovoltaic and wind power are underutilized due to the endemic problems such as difficulties of output control and intermittent output. The Energy Storage System (ESS) is proposed as a good solution for solving the problems and has been studied in both the private business and the government. However, because of inefficient aspects, the research has been carried out for improving high costs and a small capacity. In addition, the ESS is currently installed for using only one purpose which is frequency regulation or transmission congestion relief such that has an economic limitation. Therefore, methods which are becoming economically justifiable to increase the penetration of the ESS is required. Thus, this paper presents in terms of operation efficiency to improve economic feasibility of the ESS currently used. mainly, there are two aspects for the operation efficiency. Firstly, it is intended to improve the utilization rate through a process that can utilize the ESS for various purposes. It is necessary to be able to use for other purposes by classifying and clustering for increasing the efficiency of availability. The clustering method is proposed to conduct the grouping the ESS. Especially, it is proposed to utilize ESS for frequency regulation service which is the one of ancillary services in the power system. Through case studies, it is confirmed to secure the necessary resources by clustering small size ESS.

• 해양환경안전학회지
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• 제11권2호
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• pp.1-8
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• 2005

현행 목포항의 항로는 달리도 등대 수역과 고하도 만곡부 지점을 대각도로 변침해야 함으로 국$\cdot$내외의 항로선계지침을 충족하지 못하고 있다. 또한 항로 주변에 천소가 존재하고 제2항로의 신설로 인한 통항선박의 항법문제, 항로표지의 재배치 및 신실 등이 필요하다. 따라서 본 연구에서는 목포항 접근수역에 대한 자연환경, 해양사고, 해상교통량 및 해상교통흐름실태조사, 어업현황 등을 조사$\cdot$분석하고, 전문가 및 이용자에 대한 설문조사 및 국내외 항로설계지침과의 적절성 등을 검토하여 개선안을 도출하고자 한다. 또한 개선안에 대한 해상교통류시뮬레이션 및 선박조종시뮬레이션을 실시하여 타당성을 검증한다.

• Archives of Reconstructive Microsurgery
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• 제13권1호
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• pp.74-81
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• 2004

This study was designed to introduce the cross-leg free flap only for vein anastomosis as an alternative salvage method for the reconstruction of severe soft tissue defects in vascular-compromised lower extremities. Four cross-leg free flap reconstructions were performed using the latissimus dorsi muscle to reconstruct soft tissue defects in the lower extremity. The recipient artery was confined to the ipsilateral side and the venous anastomosis was carried out in the contralateral side. Both legs were immobilized together with an external fixator. All patients were males, and had a mean age of 31 years. The mean time of pedicle division was 8.8 days range of 7 to 10 days. The mean size of the flap was 186.5 cm2. All flaps survived after pedicle division without venous congestion. There was no complication in joint stiffness, nor donor site morbidity except for a linear scar. The cross-leg free flap only for vein anastomosis is a refinement of a salvage procedure used for the reconstruction of severe soft tissue defects in vascular-compromised lower extremities.

• Radiation Oncology Journal
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• 제9권2호
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• pp.227-232
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• 1991

기관지 폐색으로 호흡곤란을 유발하는 기관지내 악성종양을 치료하기 위한 방사선 치료방법으로 고선량 기관지내 근접치료법이 본원에서 시행되었다. 기관지 내시경 시술을 이용하여 근접치료용 관을 기관지 내로 삽입하며 microSelectron HDR Ir-192를 이용하여 고선량 근접치료를 시행하였다. 이 논문에서 저자들의 경험을 소개하고 이 새로운 근접치료 시술이 효과적이면서도 외래 환자로 통근 치료도 가능할 정도로 용이하고 안전한 치료법으로 자세한 기술적 인 점을 설명하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권8호
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• pp.2188-2208
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• 2023

Quality of Service (QoS) is a critical feature of Wireless Sensor Networks (WSNs) with routing algorithms. Data packets are moved between cluster heads with QoS using a number of energy-efficient routing techniques. However, sustaining high scalability while increasing the life of a WSN's networks scenario remains a challenging task. Thus, this research aims to develop an energy-balancing component that ensures equal energy consumption for all network sensors while offering flexible routing without congestion, even at peak hours. This research work proposes a Gravitational Blackhole Search Optimised splay tree routing framework. Based on the splay tree topology, the routing procedure is carried out by the suggested method using three distinct steps. Initially, the proposed GBSO decides the optimal route at initiation phases by choosing the root node with optimum energy in the splay tree. In the selection stage, the steps for energy update and trust update are completed by evaluating a novel reliance function utilising the Parent Reliance (PR) and Grand Parent Reliance (GPR). Finally, in the routing phase, using the fitness measure and the minimal distance, the GBSO algorithm determines the best route for data broadcast. The model results demonstrated the efficacy of the suggested technique with 99.52% packet delivery ratio, a minimum delay of 0.19 s, and a network lifetime of 1750 rounds with 200 nodes. Also, the comparative analysis ensured that the suggested algorithm surpasses the effectiveness of the existing algorithm in all aspects and guaranteed end-to-end delivery of packets.

• 한국지반환경공학회 논문집
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• 제23권4호
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• pp.29-39
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• 2022

도심지의 심각한 교통체증을 해결하기 위해 지하차도, 대심도 지하도로, 광역급행철도 등 대규모 지하공간 개발이 이루어지고 있다. 도심지 지하차도로 건설로 인해 인접한 도시철도 A호선 교각기초 영향 최소화 및 안정성 확보를 위해 흙막이 가시설 보강, 기초 보강 등을 실시하였다. 본 연구에서는 근접도 평가와 함께 지하차도 굴착공사로 인한 안정성을 검토하기 위해 3차원 유한요소해석을 수행하고 수치해석 결과를 통해 보강효과를 정량적으로 분석하였다. 분석결과 기존 보강을 수행한 결과에 비해 겹침 CIP와 지반보강 그라우팅을 실시할 경우 흙막이 가시설 벽체 변위는 50% 이상 저감되었고 기초말뚝의 응력에서도 45% 이상 감소 효과가 있었다. 수치해석결과 분석을 토대로 근접시공 시 보강그라우팅, 가시설 벽체의 강성 증대 등을 통해 가시설 벽체의 변위 발생을 적극적으로 억제해야 함을 확인할 수 있었다.

• 대한교통학회지
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• 제17권2호
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• pp.7-19
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• 1999

본 연구의 목적은 통신업무(Telecommuting)의 교통대체에 대한 직·간접영향을 분석하는 것으로 통근통행을 중심으로 분석하였다. 이를 위하여 우선 국내외의 통신업무 실시사례와 특성을 분석하였다. 다음으로 실증분석을 위해 RP (Revealed Preference)와 SP(Stated Preference)조사를 실시하였다. RP조사는 응답자의 정보기술에 대한 인식과 직업특성, 교통이용특성 등을 조사하였고 SP조사는 어떠한 조건이 응답자로 하여금 통신 업무를 수행하도록 유도할 수 있는지에 대하여 조사하였다. 조사결과 고임금과 통신설비에 대한 보조가 통신업무로의 전환을 효과적으로 유도하는 것으로 나타났다. 서울시에 통신업무를 시행하였을 경우 49.1%의 근로자가 통신업무로 전환될 수 있는 것으로 나타났고, 이로 인한 교통대체효과는 연간 74조 4천억원의 직·간접교통 비용을 절감하는 것으로 분석되었다. 본 연구결과 통신업무는 교통혼잡을 효과적으로 감소시킬 수 있는 대안으로 판별되었다.