• 한국통신학회논문지
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• 제37C권11호
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• pp.1170-1181
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• 2012

다양한 응용에서 사용되고 있는 무선 센서 네트워크(WSN)는 저가의 센서 노드를 구성하기 위해 배터리, 메모리 크기, MCU, RF transceiver 등과 같은 하드웨어에서 제약을 갖고 있다. 특히, 센서 노드의 제한된 에너지는 네트워크 수명과 직접적인 관련이 있기 때문에 네트워크 수명을 연장하기 위한 효율적인 알고리즘이 요구된다. 군 환경에서 침입자를 탐지하기 위한 감시 정찰 응용은 이벤트 구동형(event-driven) 전송 모델로써, 이벤트 발생 빈도가 드물고(rare), 폭발적(bursty), 지역적(local)으로 발생하는 특징이 있다. 이와 같은 응용에서는 Data Aggregation의 장점이 있는 클러스터링 알고리즘을 이용하는 것이 각 노드가 개별적으로 데이터를 전송하는 것 보다 데이터 전송량을 줄여 에너지 효율을 높일 수 있다. 하지만 기존의 클러스터링 알고리즘은 감시 정찰 응용의 이벤트 발생에 대한 특징을 고려하고 있지 않기 때문에 여러 문제가 발생한다. 본 논문에서는 이러한 문제를 개선한 감시 정찰 응용에서의 에너지 효율적인 클러스터링 알고리즘을 제안한다. 이 알고리즘은 타깃을 탐지한 노드들이 각각 Cluster Head Election Window (CHEW)를 생성하여 지역적 경쟁 방식으로 클러스터를 구성하고, 타깃의 이동성을 고려하였다. 시뮬레이션 결과에서는 타깃의 이동에 따라 클러스터가 형성되는 자취를 분석하고, 에너지 효율이 증가되는 것을 증명하였다.

• 암석학회지
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• 제14권3호
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• pp.169-179
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• 2005

계명산층 내의 충주 철광상 부근에서 산출되는 산성 변성화산암들은 매우 높은 희토류 원소 및 고장력 원소 농도를 갖는다. 비교적 높은 ${\epsilon}_{Nd}$(0) 값과 결여된 Nb(-) 이상치는 이들의 형성에 지각물질에 의한 혼염이 수반되지 않았음을 시사한다. 또한 지구조 판별도에서 판내부 환경에 도시된다. 이러한 지구화학적 특징들은 750Ma의 연대를 보이는 문주리층의 산성변성화산암과 매우 비슷하다. 이들은 Al-형(Eby, 1992)에 분류되는 마그마의 지구화학적 특징을 나타내며, 대륙의 분열과 관련된 열곡환경에서 맨틀기원의 마그마가 분화되어 생성되었음을 지시한다. 약 330Ma의 연대를 보이는 충주 철광상 부근의 알칼리 화강암 및 희유금속광상과는 달리 동일지역에서 산출되는 산성 변성화산암들의 Sm-Nd 동위원소 자료는 명확한 동시선을 형성하지 않는다. 또한 낮은 ${\epsilon}_{Nd}$(0) 값을 갖는 알칼리 화강암과는 달리 산성 변성화산암과 희유금속광상은 비교적 높은 ${\epsilon}_{Nd}$(0) 값을 갖는다. 이러한 차이에 근거하여 다음과 같은 생성가설을 제시한다: 계명산층 내의 충주 철광상 부근에 분포하는 산성 변성화산암은 계명산층의 다른 지역과 문주리층 내의 산성 변성화산암들과 마찬가지로 신원생대인 750Ma에 생성되었다. 약 330Ma 경에 기존 Al-형 화성암과 일부 오래된 지각물질의 용융으로 알칼리 화강암이 생성되었다. 이와 동시에 열수작용으로 인한 산성 화산암 내의 물질 재배치로 희유금속광상이 형성되었으며, 뒤이은 약 280Ma경의 광역변성작용시 산성 변성화산암의 Nd-Sm 동위원소계가 교란되었다.

• The Korean Journal of Pain
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• 제9권2호
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• pp.430-433
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• 1996

It is common practice to use epidural catheter for anesthesia or for postoperative analgesia and other kinds of pain control. However, Intraspinal infection associated with this practice is rare event. We report a case of spinal subdural abscess occuring in patient who had recently received epidural catheterization. The cause in this case is not certain, although infection from the epidural catheter is the best possibility. We recommand an aseptic technique in all procedure for epidural or spinal analgesia.

• Journal of Korean Neurosurgical Society
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• 제46권5호
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• pp.492-494
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• 2009

The authors report a case of recurrent subarachnoid hemorrhage (SAH) after complete occlusion of an intracranial aneurysm. It is known that regrowth of an aneurysm after the complete clipping is a rare event. For detection of recurrence, however, it may be necessary to follow up with the patient regularly after the initial operation for intracranial aneurysms, because re-rupture of an aneurysm can cause a fatal result, and the cumulative risk of a recurrent SAH is thought to be not low over time.

• Journal of Korean Neurosurgical Society
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• 제53권2호
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• pp.125-128
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• 2013

A 65-year-old man who had lateral cervical disc herniation underwent cervical posterior laminoforaminotomy at C5-6 and C6-7 level right side. During the operation, there was no serious surgical bleeding event. After operation, he complained persistent right shoulder pain and neck pain. Repeated magnetic resonance image (MRI) showed diffuse cervical epidural hematoma (EDH) extending from C5 to T1 level right side and spinal cord compression at C5-6-7 level. He underwent exploration. There was active bleeding at muscular layer. Muscular active bleeding was controlled and intramuscular hematoma was removed. The patient's symptom was reduced after second operation. Symptomatic postoperative spinal EDH requiring reoperation is rare. Meticulous bleeding control is important before wound closure. In addition, if patient presents persistent or aggravated pain after operation, rapid evaluation using MRI and second look operation is needed as soon as possible.

• Journal of Chest Surgery
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• 제28권5호
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• pp.495-498
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• 1995

Pulmonary arteriovenous fistula can be either congenital or acquired. The vast majority are congenital, and about 60% have been associated with hereditary hemorrhagic telangiectasia [Rendu-Osler-Weber disease . Secondary or acquired pulmonary arteriovenous fistula occurs with trauma, schistosomiasis, long-standing hepatic cirrhosis, metastatic carcinoma, and actinomycosis. Pulmonary hemorrhage secondary to acquired pulmonary arteriovenous fistula is a rare event associated with mortality. We have experienced 64 year-old female patient with the hemoptysis secondary to acquired pulmonary arteriovenous fistula due to the infection of pulmonary parasite. The chest PA and CT scan was showed calcified nodule to the distal portion of lateral segmental bronchus of RML. The bronchial angiogram was demonstrated slightly hypertrophied bronchial artery supplying RML bronchus and the presence of hypervascularization around the calcified nodule, rapid A-V shunting is noted by fluoroscopy. The patient was successfully treated by the right middle lobectomy.

• Journal of Korean Neurosurgical Society
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• 제53권1호
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• pp.43-45
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• 2013

"Tumor-to-tumor" metastasis is a rare event; meningioma has been reported as the most common primary intracranial tumor to harbor cancer metastases. Several hypotheses have been previously proposed to explain this occurrence, but the exact mechanism by which these metastases develop into meningiomas is not yet understood. Magnetic resonance imaging and spectroscopy have been valuable diagnostic tools, but preoperative diagnosis of metastasis to meningioma remains highly difficult. We present a case report of a metastasis of non-small cell lung cancer into an intracranial meningioma.

• Imaging Science in Dentistry
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• 제42권1호
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• pp.55-60
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• 2012

Gorlin-Goltz syndrome is an autosomal dominant disorder principally characterized by cutaneous basal cell carcinomas, multiple keratocystic odontogenic tumors, and skeletal anomalies. This syndrome may be diagnosed early by dentist because keratocystic odontogenic tumors are usually one of the first manifestations of the syndrome. Early diagnosis and treatment are of utmost importance in reducing the severity of long term sequelae of this syndrome. This report presents a rare event of Gorlin-Goltz syndrome occurring in a 39-year-old male and his 8-year-old daughter. The clinical and investigative features of this familial disorder has been described in detail.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.371-376
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• 2007

This paper describes a study to determine proper escape way interval for the design phase of single bored double track tunnel. Among many methods which determine escape way interval, we choose a QRA(Quantitative Risk Analysis) method. But a different method must be chosen differ from other country because of special design situation of Korea. So, it is necessary to develop a method which considers a special design condition of Korea. Because fire accidents of railway tunnel are a rare event, simulated situation can be produced by CFD simulation and evacuation analysis simulation. However, it is generally difficult to estimate of fatalities from these methods, so a concept of FED is introduced to estimate of fatalities. Quantification process provides effective results for practical design stage and the result were employed in design.

• Journal of Trauma and Injury
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• 제30권4호
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• pp.220-226
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• 2017

Traumatic dissection of the celiac artery without aortic dissection is a rare event. Here we describe two cases of celiac artery dissection after blunt abdominal trauma managed conservatively without surgical or endovascular intervention.