저전력 마이크로컨트롤러를 위한명령어 레벨의 소모전류 모델링 및 최적화에 대한 연구

엄흥식,김건욱 대한전자공학회 2006 電子工學會論文誌-CI (Computer and Information) Vol.43 No.5

본 논문에서는 임베디드 시스템에서 사용되는 대표적 저전력 마이크로컨트롤러인 ATmega128을 대상으로 명령어 레벨의 소모전류를 측정, 모델링하였다. 마이크로컨트롤러가 소모하는 전류는 메모리의 접근 유무에 의해 차이가 나며, 메모리 접근 명령어가 메모리 비접근 명령어에 비해 내부 메모리 기준으로 17% 더 높은 전류소모를 나타낸다. 프로그램의 메모리 접근 명령어 사용빈도가 높을수록, 메모리 계층구조에서 낮은 계층의 정보를 접근할수록 프로그램의 전력소모는 비례한다고 관찰된다. 본 논문에서는 명령어 레벨의 소모전류모델화를 통하여 실제 프로그램의 전력소모를 예측, 분석하고 메모리 접근 명령어의 비율을 줄이는 방향으로 프로그램의 전력소모를 최적화한다. 또한 마이크로컨트롤러 기반 시스템에서 프로그램 실행 전력을 최적화할 수 있는 기법을 하드웨어와 소프트웨어 측면에서 다양하게 제안한다. This paper presents experimental instruction-level current consumption model for low power microcontroller ATmega128. The accessibility of instruction for internal memory decides power consumption of the microcontroller as much as 17% of difference between access instruction and non-access instruction. The power consumption for the given program will be increased in the proportional to the ratio of memory access instruction and lower level memory access in the hierarchy. Throughout the current consumption model, the power consumption can be predicted and optimized in the direction of reducing the frequency memory access. Also, the various optimization methods are introduced in terms of software and hardware viewpoints.

20대의 치주염 진행에 대한 2년간의 종적연구

엄흥식,Um, Heung-Sik 대한치주과학회 1998 Journal of Periodontal & Implant Science Vol.28 No.3

The purpose of this investigation was to examine the pattern of progression of periodontitis and the change in the extent and severity of the periodontal condition in young adults. Fourteen subjects with periodontitis, 11 males and 3 females in the age range 22-26, participated in the study. Following a baseline examination, the subjects were monitored for gingival index, probing pocket depth, gingival recession, probing attachment level and radiogrphic crestal bone height for 24 months without therapy. Re-examination were performed after 12 and 24 months. Gingival index, probing pocket depth, gingival recession and probing attachment level were assesed at 6 locations per tooth, and crestal bone height was assessed by subtraction radiography. The results from the follow-up examination revealed that the subjects underwent minor changes with respect to a series of different clinical parameters. The mean values of gingival index was improved, however, the mean values of probing pocket depth, gingival recession, probing attchment level and crestal bone height showed no significant change between baseline and the re-examination after 1 and 2 years.

치조골내낭에 수종의 골이식재 이식후 혈소판 유래 성장인자의 분포에 관한 면역조직화학적 연구

엄흥식,한수부,이재일,김현종,장범석,Um, Heung-Sik,Han, Soo-Boo,Lee, Jae-Il,Kim, Hyun-Jong,Chang, Beom-Sek 대한치주과학회 1997 Journal of Periodontal & Implant Science Vol.27 No.1

Platelet-derived growth factor(PDGF) has been shown to play an important role in periodontal regeneration. The purpose of the present study was to examine the distribution of PDGF in experimentally created periodontal intrabony defects after flap surgery with various bone graft materials. Six healthy mongrel dogs were used in this study. Three-wall bony defects were created in maxillary and mandibular premolars, inflammation induced by wire ligation and injection of impression material into the defects. Eight weeks later, the experimental lesions thus obtained were treated by plain flap surgery(control group), flap surgery plus autogenous bone graft(autogenous bone group), flap surgery plus Biocoral graft(Biocoral group), or flap surgery plus bioglass graft(bioglass group), which were randomly assigned to the defects. After 4, H, and 12 weeks postoperatively, 2 dogs were sacrificed at each time and 1he specimens were taken for histological examinations and immunohistochemical examinations for PDGF. In the control defects the amount of new bone formation was minimal. In the autogenous bone and Biocoral group new bone was deposited around implanted particles and the amount of new bone was increased with time. A large number of bioglass particles exibited a central excabation and bone formation could be observed in the central excabation as well as around the particles. The expression of PDGF was low in the control group. The expression of PDGF in Biocoral group was increased at 1, H week, but decreased at 12 week. The increased PDGF expression in autogenous bone and bioglass group was maintained to the end of the experiment.

Porphyromonas gingivalis와 Tannerella forsythia의 응집반응

엄흥식,이석우,박재홍,Um, Heung-Sik,Lee, Seok-Woo,Park, Jae-Hong,Nauman, R.K. 대한치주과학회 2006 Journal of Periodontal & Implant Science Vol.36 No.1

Dental plaque, a biofilm consisting of more than 500 different bacterial species, is an etiological agent of human periodontal disease, It is therefore important to characterize interactions among periodontopathic microorganisms in order to understand the microbial pathogenesis of periodontal disease. Previous data have suggested a synergistic effect of tow major periodontal pathogens Porphyromonas gingivalis and Tannerella forsythia in the periodontal lesion. In the present study, to better understand interaction between P. gingivalis and T. forsythia, the coaggregation activity between these bacteria was characterized. The coaggregation activity was observed by a direct visual assay by mixing equal amount (1 ${\times}$ $10^9$)of T. forsythia and P. gingivaJis cells. It was found that the first aggregates began to appear after 5-10 min, and that the large aggregates completely settled within 1 h. Electron and epifluorescence microscopic studies confirmed cell-cell contact between two bacteria. The heat treatment of P. gingivalis completely blocked the activity, suggesting an involvement of a heat-labile component of P. gingivalis in the interaction. On the other hand, heat treatment of T. forsythia significantly increased the coaggregation activity; the aggregates began to appear immediately. The coaggregation activity was inhibited by addition of protease, however carbohydrates did not inhibit the activity, suggesting that coaggregation is a protein-protein interaction. The results of this study suggest that coaggregation between P. gingivalis and T. forsythia is a result of cell-cell physical contact, and that coaggregation is mediated by a heat-labile component of P. gingivalis and T. forsythia component that can be activated on heat treatment.

Chlorhexidine을 이용한 치주낭 세척이 치주염에 이환된 치근내 침투세균에 미치는 영향

엄흥식,한수부,Um, Heung-Sik,Han, Soo-Boo 대한치주과학회 1989 Journal of Periodontal & Implant Science Vol.19 No.2

신농양에 동반된 척추 경막외 농양 1예

엄흥식,김준재,김현수,박영정,최상봉,박원도,김상현 인제대학교 2006 仁濟醫學 Vol.27 No.-

Spinal epidural abscess is an uncommon but readily diagnosable and treatable potential cause of paralysis and death. The incidence of spinal epidural abscess is approximately one to two cases per 10,000 hospital admissions in the United States. The symptoms of spinal epidural abscess are varied but include lower back pain, fever, local tenderness and neurological deficit, especially in such high risk groups as patients with diabetes, intravenous drug abuse, chronic renal failure, alcoholism, liver disease and immunocompromization. Infections of the epidural space originate from contiguous spread or via hematogenous routes from a distant source. Cutaneous sites of infection are the most common remote sources, especially in intravenous drug users. S. aureus accounts for most spinal epidural abscess infections, followed by streptococci and gram-negative anaerobes. We here report a case of spinal epidural abscess in renal abscess patient complaining of fever and back pain. A 71-year old female patient was admitted to epigastric pain and oliguria. She had been diagnosed as acute renal failure and treated with hydration. After third hospital days, she shows a persistent fever and drowsy mentality. Abdominal computed tomography demonstrated renal abscess. She was treated with intravenous antibiotics, third cephalosporin. Blood cultures and urinary culture revealed Escherichia, coli. After fourteenth hospital days, she developed back pain, muscle weakness and decreased sensation of lower extremities. Spine MRI demonstrated spinal epidural abscess with spinal cord compression. Surgical drainage with laminectomy was performed. After treatment of intravenous antibiotics and surgical drainage, she discharged with improved back pain and neurological symptom.

치주질환의 분류

엄흥식 대한치과의사협회 1999 대한치과의사협회지 Vol.37 No.3

치석제거술과 치근면활택술

엄흥식,장범석 대한치과의사협회 2000 대한치과의사협회지 Vol.38 No.11

전송전력 최적화를 통한 센서네트워크의 효율적인 에너지관리에 대한 연구

엄흥식,김건욱 대한전자공학회 2007 電子工學會論文誌-CI (Computer and Information) Vol.44 No.3

This paper reconsiders established power conservation models for ubiquitous sensor networks that use relay nodes instead of direct communication and proposes novel network power consumption model with consideration of the channel level and radio chip level simultaneously. We estimate the effect of minimum hop-count policy in terms of network power consumption through simulation of various situations for low power RF module CC2420. It is observed that maximum RF power and minimum hop-count results in lower energy consumption relatively. Also, in total network energy consumption, which is included re-transmission, minimum hop count policy presents decrease by 33.1% of energy consumption in compare with the conventional model. 본 논문에서는 무선채널의 신호감쇄특성으로 인하여 멀티홉을 통한 센서네트워크의 에너지소비를 최소화하려는 기존의 연구를 재해석하고 무선채널의 특성과 하드웨어의 전력소비를 동시에 고려하여 센서네트워크의 에너지소비를 모델링하였다. 또한 센서네트워크 하드웨어 플랫폼에 주로 사용되고 있는 RF모듈인 Chipcon사의 CC2420을 대상으로 최대 전송전력과 최소의 홉을 통한 데이터 전송이 네트워크의 에너지효율에 미치는 영향을 다양한 상황의 시뮬레이션을 통해 검증한다. 최대 전송전력으로 최소의 홉을 통하여 전송했을 경우, 낮은 전송전력으로 여러 홉을 거쳐 데이터를 전송하는 것보다 네트워크의 에너지소비가 적게 발생하는 것으로 관찰된다. 높은 전송전력에 따라 증가하는 재전송을 고려한 결과 또한 최대 전송전력으로 전송했을 경우 최대 33.1%의 에너지효율을 얻을 수 있다.

수종의 골연하치주낭 치료법의 임상적 효과에 관한 연구

엄흥식(Um, Heung-Sik) 대한치과의사협회 1994 대한치과의사협회지 Vol.32 No.9