• 한국정보과학회논문지:시스템및이론
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• 제31권8호
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• pp.473-486
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• 2004

NUMA 시스템은 원격의 메모리에 반복적으로 접근하는 오버헤드를 피하기 위해 지역 노드내에 원격 캐시를 둔다. 이러한 원격 캐시를 사용하여 원격 메모리로의 접근 지연 시간을 감소시키고 네트워크 상의 트래픽 양을 줄이지 못한다면 다중 프로세서 시스템의 성능 저하는 명백하다. 성능 상의 여러 기준 중에서 메모리 시스템과 관련해서는 캐시 교체 정책에 관한 연구가 계속되었고, 그 중 다중 프로세서 시스템에서의 캐시 교체 정책에 관한 연구도 이어졌다. 본 논문에서는 캐시의 공유 상태에 기반을 둔 교체 정책을 제안한다. 소유권이 없는 캐시 라인을 먼저 교체하고, 이를 통해 소유권이 옮겨지는 오버헤드를 피하여 메모리 지연 시간을 줄인다. 또한 소유권이 없는 캐시 라인에 지나친 피해가 얼도록, “MRU를 사용한 소유권 유지 교체 정책(KOM)”과 “참조 비트를 사용한 소유권 유지 교체 정책(KORB)”를 제안하고, 이를 LRU, Pseudo LRU(PLRU)와 비교한다. KOM과 KORB는 PLRU에 비하여 수행 시간에서 25%, 13%씩 각각 향상을 보였다. 특히 KOM은 하드웨어 복잡도가 현저히 낮음에도 불구하고 LRU에 가까운 성능을 나타냈다.

• 한국재난정보학회 논문집
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• 제14권3호
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• pp.305-314
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• 2018

연구목적: 동치환공법은 유사한 동다짐공법에 비해 동치환 직경, 심도, 간격, 타격에너지(중추 무게와 낙하고), 지반강도 증대 효과, 지반 개량효율 등에 대한 연구 및 실증이 부족하다. 연구방법: 본 연구에서는 실트질 점토지반을 연구 대상 지반으로 선정하여 예비 동치환시공과 본시공 동치환의 2가지 경우로 나눠서 지반개량을 실시하고 효과를 분석하였으며, 결과를 바탕으로 적정 개량심도 결정 및 개량효과에 미치는 인자에 관하여 연구하였다. 연구결과: 실트질 점토 지반을 대상으로 동치환 적정 심도 결정, 지반개량효과에 끼치는 특성을 상세히 분석하여 동치환 시 적용할 수 있는 개량심도 ($D_R$) 관계식을 제안하였다. 결론: 동치환공법을 실트질 점토 지반에 적용한 경우, 동다짐공법의 낙하에너지보다 1.25~2.5배 증가시켜야 하는 것으로 나타났다.

• Journal of Chest Surgery
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• 제19권1호
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• pp.108-115
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• 1986

During 12 years period from 1974 to 1985, 76 valve replacement procedures were performed at Seoul National University Hospital in 67 pediatric patients aging up to 15 years [mean 12.3 years] and it was 7.3% of total valve replacement procedures in same period. Sixty seven patients were composed of 44 males and 23 females. Of the 67 patients, 43 patients had acquired valve lesions and 24 patients congenital valve lesions. Sixty cases received single valve replacement, 7 cases double or triple valve replacement and 9 cases redo-valve replacement. Sixty seven patients received 84 valves [65 bioprosthetic valves and 19 prosthetic valves by] 76 operations, Sixty three of 65 bioprosthetic valves had been replaced before 1983 and 15 of 19 prosthetic valves in recent 2 years. Eleven patients [14.6%] died within one month post-operatively and 8 patients [10.5%] during the follow-up period with the overall mortality rate of 25.1%. There were early post-operative complication of 23 cases [30.3%] and late post-operative complication of 27 cases [35.3%] with the total complication rate of 65.8%. In 58 patients received bioprosthetic valves, there were 14 cases of restenosis of replaced valves. Of the 14 cases of bioprosthetic valve restenosis, 8 cases received redo-valve replacement procedures without mortality in 1 5/12-5 years after initial operation but 4 cases died without reoperation and 2 cases lost during follow-up. The overall mortality and complication rate were still high but they markedly decreased during recent 2 years. So, in spite of its containing many problems, valve replacement in children is becoming safe and useful procedure in whom valve reconstructive procedures are impossible.

• 스마트미디어저널
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• 제6권2호
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• pp.33-41
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• 2017

철도 선로전환기는 열차의 진로를 현재의 궤도에서 다른 궤도로 제어하는 장치이다. 선로전환기의 노후화로 인한 이상 상황은 탈선 등과 같은 심각한 문제를 발생할 수 있기 때문에, 선로전환기의 적절한 교체시기를 결정하는 것은 매우 중요하다. 본 논문에서는 국내 철도 현장에서 획득한 선로전환기의 전류신호로부터 다차원 데이터 큐브를 구성하고 OLAP(On-Line Analytical Processing) 분석을 통하여 체계적으로 "교체가 필요한 데이터"와 "교체 시점이 아닌 데이터" 집합을 정제하여 분류하였다. 또한 선로전환기의 교체시기 탐지 문제를 이진 분류 문제로 해석하여 이진 분류기의 대표적 모델인 SVM(Support Vector Machine)을 탐지기로 설계함으로써 선로전환기의 노후화에 따른 적절한 교체시기를 탐지하는 시스템을 제안한다. 이때, 입력되는 전류 신호를 DWT(Discrete Wavelet Transform)와 PCA(Principal Components Analysis) 기법으로 고차원의 특징벡터 신호를 정보의 손실을 최소화하면서 저차원의 특징벡터로 변환한다. 실제 국내에서 운행 중인 선로전환기의 이상상황 정보가 포함된 대규모의 전류 신호를 이용하여 제안하는 시스템의 성능을 실험적으로 검증한 바 98%를 넘는 탐지 정확도를 확인하였다.

• Journal of Korean Neurosurgical Society
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• 제62권1호
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• pp.83-89
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• 2019

Objective : This study is a retrospective cost-benefit analysis of cervical anterior interbody fusion and cervical artificial disc replacement, which are the main surgical methods to treat degenerative cervical disc disease. Methods : We analyzed 156 patients who underwent anterior cervical disc fusion and cervical artificial disc replacement from January 1, 2008 to December 31, 2009, diagnosed with degenerative cervical disc disorder. In this study, the costs and benefits were analyzed by using quality adjusted life year (QALY) as the outcome index for patients undergoing surgery, and a Markov model was used for the analysis. Only direct medical costs were included in the analysis; indirect medical costs were excluded. Data were analyzed with TreeAge Pro $2015^{TM}$ (TreeAge Software, Inc, Williamstown, MA, USA). Results : Patients who underwent cervical anterior fusion had a total cost of KRW 2501807/USD 2357 over 5 years and obtained a utility of 3.72 QALY. Patients who underwent cervical artificial disc replacement received 4.18 QALY for a total of KRW 3685949/USD 3473 over 5 years. The cumulative cost-effectiveness ratio of cervical spine replacement surgery was KRW 2549511/QALY (USD 2402/QALY), which was lower than the general Korean payment standard. Conclusion : Both cervical anterior fusion and cervical artificial disc replacement are cost-effective treatments for patients with degenerative cervical disc disease. Cervical artificial disc replacement may be an effective alternative to obtain more benefits.

• Structural Engineering and Mechanics
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• 제70권2호
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• pp.169-178
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• 2019

The replacement of damaged components is an important task for long-span bridges. Conventional strategy for component replacement is to close the bridge to traffic, so that the influence of the surrounding environment is reduced to a minimum extent. However, complete traffic interruption would bring substantial economic losses and negative social influence nowadays. This paper investigates traffic control technologies without interruption for component replacement of long-span bridges. A numerical procedure of traffic control technologies is proposed incorporating traffic microsimulation and site-specific data, which is then implemented through a case study of cable replacement of a long-span cable-stayed bridge. Results indicate traffic load effects on the bridge are lower than the design values under current low daily traffic volume, and therefore cable replacement could be conducted without traffic control. However, considering a possible medium or high level of daily traffic volume, traffic load effects of girder bending moment and cable force nearest to the replaced cable become larger than the design level. This indicates a potential risk of failure, and traffic control should be implemented. Parametric studies show that speed control does not decrease but increase the load effects, and flow control using lane closure is not effectual. However, weight control and gap control are very effective to mitigate traffic load effects, and it is recommended to employ a weight control with gross vehicle weight no more than 65 t or/and a gap control with minimum vehicle gap no less than 40 m for the cable replacement of the case bridge.

• Communications for Statistical Applications and Methods
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• 제6권2호
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• pp.403-412
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• 1999

A block replacement policy where at failure the item is either replaced by a new or used item or remains inactive until the next planned replacement is considered. in this paper our interests are focused on reusing all the used items created by the policy. Numerical results for the case where the underlying life distribution is gamma are obtained.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.281-286
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• 2002

To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment of curing temperature $35^{\circ}C$, . Flesh concrete tested slump. air contest and Hardening concrete valuated setting period of form, day of age 1, 3, 5. 7, 10, 28 compression strength in sealing curing. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Experiment result age 28day compression strength more higher plan concrete then standard environment in curing temperature $20^{\circ}C$, , most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$, replacement binder 25%, fine aggregate 15%. (2) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

• The Journal of Korean Physical Therapy
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• 제25권6호
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• pp.417-421
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• 2013

Purpose: This study was to identify the effect of cervical stabilization exercise on pain and structure in patients with cervical artificial disc replacement. Methods: Forty-four individuals with cervical artificial disc replacement volunteered to participate from FEB 2012 to MAR 2013 in this study. They were allocated to either Experimental Group (EG) or Control Group (CG), with 22 subjects in each group. Subjects from the EG performed cervical stabilization exercise program and subjects from the CG performed isometric exercise program. Assessment tools were made with the Visual Analogue Scale (VAS), Neck Disability Index (NDI), and Cervical Lordosis Angle (CLA). Results: In this study, in within-group and between-group comparison, the EG and CG showed significant differences in all parameters(p<0.05). But EG showed more improvement than CG at all parameters. Conclusion: These findings suggest that cervical stabilization exercise may be favorably used to improve VAS, NDI and CLA in patients with cervical artificial disc replacement. Further studies with larger sample and long-term follow-up period need to generalize the results of this study.

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2691-2696
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• 2013

The electronic cigarette (E-cigarette) is a battery-powered device that aerosolizes nicotine so that it is readily delivered into the respiratory tract. The analytical data regarding the substances present in E-cigarettes are very limited. The aim of this study was to measure the concentration of aldehydes-formaldehyde (FA), acetaldehyde (AA) and, acrolein (AL)-in 225 replacement liquid brands from 17 E-cigarette shops sold in the Republic of Korea by headspace solid-phase micro extraction and gas chromatography-mass spectrometry (HS-SPME GC-MS). The concentration range of FA and AA was 0.02-10.09 mg/L (mean = 2.16 mg/L, detected in 207 of 225 samples) and 0.10-15.63 mg/L (mean = 4.98 mg/L, detected in all samples), respectively. AL was not detected in any of 225 replacement liquids. FA and AA were originally present in almost all replacement liquids of electronic cigarettes.