• 한국통신학회논문지
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• 제24권10B호
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• pp.1832-1840
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• 1999

논문에서는 WDM 기술을 사용하는 완전 광전달망에서 장애를 복구할 수 있는 양 방향 BLSR/4 WDM/SHR 구조의 네트워크를 설계하였다. 제안한 네트워크는 전기적 기능이 없는 완전 광소자를 사용하여 높은 수준의 투명성을 제공하고, BLSR/4 SHR 구조를 사용함으로써 장애 복구를 효율적으로 수행할 수 있다. 또한, 제안한 BLSR/4 WDM/SHR의 여러 장애에 대한 생존성을 분석하기 위한 모델을 제시하였으며, 전파 시간, 처리 시간, 절체 시간의 파라미터를 사용하여 복구 성능을 분석하였다.

• Korean Circulation Journal
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• 제52권12호
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• pp.878-886
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• 2022

Background and Objectives: Moderate aortic stenosis (AS) confers a surprisingly adverse prognosis, approaching that of severe AS. The objective of this study was to describe the clinical course of patients with moderate AS with evidence of concomitant heart failure manifesting as elevated brain natriuretic peptide (BNP) levels. Methods: This is a single-center, retrospective cohort study of 332 patients with elevated BNP. 165 patients with moderate AS were compared with 167 controls with none-mild AS. The Median follow-up duration was 3.85 years. The primary outcome was a composite endpoint of all-cause hospitalizations and all-cause mortality. Results: BNP levels were 530 and 515 pg/mL in the study and the control groups, respectively. Moderate AS had significantly higher rates of primary composite endpoint in both univariate analysis (hazard ratio [HR], 1.50; 95% confidence interval [CI], 1.14-1.97; p=0.004) and adjusted analysis (HR, 1.45; 95% CI, 1.05-2.01; p=0.02). Moderate AS had 1.41 (95% CI, 1.18-1.69; p<0.001) times more all-cause hospitalization per patient-year of follow-up compared to controls in the univariate model. After adjustment for significant covariates, moderate AS remained an independent predictor of all-cause hospitalizations (incidence rate ratio [IRR], 1.45; 95% CI, 1.18-1.79; p=0.005). Furthermore, moderate AS was significantly associated with higher all-cause hospitalization rates in both heart failure with reduced ejection fraction (IRR, 1.33; 95% CI, 1.02-1.75; p=0.038) and heart failure with preserved ejection fraction [IRR], 1.31; 95% CI, 1.03-1.67; p=0.026). Conclusions: Moderate AS in conjunction with elevated BNP portends a significantly worse prognosis than those without moderate AS and should be followed closely.

• 한국정보과학회논문지:정보통신
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• 제34권4호
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• pp.256-261
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• 2007

편향 자기 경로 제어 방법을 사용하는 고성능 고장 감내 스위칭 망인, 2차원 링-밴얀 망은 비균일 부하를 가하였을 경우에 사이클릭 밴얀 스위칭 망보다 성능이 우수하다. 본 논문에서는 이 망의 신뢰성 분석을 제시한다. 하드웨어 복잡도를 반영한 확률적 모형을 사용하여, 고장까지의 평균시간(Mean-Time-to-Failure)을 계산하여 제시하였다. 결과적으로, 최근에 개발된 Hui의 망 보다. $16\;{\times}\;16$ 망은 27.5%, $64\;{\times}\;64$ 망은 51.0%, 이 스위칭 망의 신뢰성이 높음을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.651-656
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• 2002

In general, the most important problem in slope stability analysis is that there is no definite way to describe the natural three-dimensional Joint network. Therefore, the many approaches were tried to anlayze the slope stability. Numerical modeling approach is one of the branch to resolve the complexity of natural system. UDEC, FLAC, and SWEDGE are widely used commercial code for the purpose on stability analysis. For the purpose on the more appropriate application of these kind of code, however, three-dimensional distribution of joint network must be identified in more explicit way. Remaining problem is to definitely describe the three dimensional network of joint and bedding, but it is almost impossible in practical sense. Three dimensional joint generation method with random number generation and the results of generation to UDEC have been applied to settle the refered problems in field site. However, this approach also has a important problem, and it is that joint network is generated only once. This problem lead to the limitation on the application to field case, in practical sense. To get rid of this limitation, Monte Carlo Simulation is proposed in this study 1) statistical analysis of input values and definition of the applied system with statistical parameter, 2) instead of the consideration of generated network as a real system, generated system is just taken as one reliable system, 3) present the design parameters, through the statistical analysis of ouput values Results of this study are not only the probability of failure, but also area of failure block, shear strength, normal strength and failure pattern, and all of these results are described in statistical parameters. The results of this study, shear strength, failure area, pattern etc, can provide the direct basement on the design, cutoff angle, support pattern, support strength and etc.

• 전자공학회논문지A
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• 제32A권8호
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• pp.1-10
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• 1995

We have analyzed the reliability of failure models in circuit-switched networks. These models are grid topology circuit-switched networks, and each node transmits a packet to a destination node using a Flooding routing method. We have assumed that the failure of each link and node is independent. We have considered two method to analyze reliability in these models : The Karnaugh Map method and joint probability method. In this two method, we have analyzed the reliability in a small grid topology circuit switched network by a joint probability method, and comared analytic results with simulated ones. For a large grid enormous. So, we have evaluated the reliability of the network by computer simulation techniques. As results, we have found that the analytic results are very close to simulated ones in a small grid topology circuit switched network. And, we have found that network reliability decreases exponentially, according to increment of link or node failure, and network reliability is almost linearly decreased according to increment of the number of links, by which call has passed. Finally, we have found an interesting result that nodes in a center of the network are superior to the other nodes from the reliability point of view.

• 한국군사과학기술학회지
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• 제10권2호
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• pp.107-114
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• 2007

This paper describes the Petri Net(PN) model for reliability analysis of fault-tolerant dual Ethernet which Is applied in Naval Combat System. The network for Naval Combat System performs failure detection and auto path recovery by handling redundant path in case of temporary link failure. After studying the behavior of this kind of network, the reliability analysis model is proposed using stochastic Petri Net and continuous-time Markov chains. Finally, the numerical result is analyzed according to changing the failure rate and the recover rate of link.

• 한국기계가공학회지
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• 제19권11호
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• pp.94-101
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• 2020

In the age of industry 4.0, artificial intelligence is being widely used to realize machinery condition monitoring. Due to their excellent performance and the ability to handle large volumes of data, machine learning techniques have been applied to realize the fault diagnosis of different equipment. In this study, we performed the failure mode effect analysis (FMEA) of an aluminum electrolytic capacitor by using deep learning and big data. Several tests were performed to identify the main failure mode of the aluminum electrolytic capacitor, and it was noted that the capacitance reduced significantly over time due to overheating. To reflect the capacitance degradation behavior over time, we employed the Vanilla long short-term memory (LSTM) neural network architecture. The LSTM neural network has been demonstrated to achieve excellent long-term predictions. The prediction results and metrics of the LSTM and Vanilla LSTM models were examined and compared. The Vanilla LSTM outperformed the conventional LSTM in terms of the computational resources and time required to predict the capacitance degradation.

• 한국통신학회논문지
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• 제36권10A호
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• pp.830-838
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• 2011

최근 무선 환경에서 네트워크 효율성 증대를 위하여 네트워크 코딩에 대한 연구들이 많이 진행되고 있다. 본 논문에서는 무선 환경에서 RLNC를 적용하기 위한 고려사항들을 분석해 본다. 우선 기존의 멀티캐스트에서 사용하는 방식으로 우선 분산 환경에 RLNC에 적용 가능한지 살펴보았다. 시뮬레이션 결과 멀티캐스트에서 사용하는 방식대로 적용한 RLNC에서는 디코딩 실패가 발생하였고, X 구조에서 인코딩과 디코딩을 모두 수행하여 디코딩 실패를 제거한 RLNC는 전송 이득이 많지 않았다. 또한 본 논문에서는 hidden 노드 문제, 코딩 기회 분석, RLNC 오버헤드 등의 무선 환경에서 실제적인 고려사항을 분석해 보았다.

• 한국시뮬레이션학회논문지
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• 제27권3호
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• pp.89-97
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• 2018

미래전에서는 무기체계의 상당부분이 무인체계로 대체될 것이며 이들은 상호 통신으로 연결되어 네트워크중심전으로 변화하고 있다. 이에 따라 무인체계 효과분석이 중요한 이슈가 될 것이다. 하지만 무인체계의 주요통제 수단인 통신장애 상황에서 UGV에 대한 효과분석 연구는 매우 미흡한 실정이다. 본 논문에서는 지형을 고려한 통신장애 상황에서 무인체계의 운용효과분석을 위한 새로운 에이전트기반 모델링 절차를 제시하였다. 추가적으로, 통신장애 상황을 극복할 수 있는 통신중계기를 추가하였을 경우 UGV운용효과의 변화에 대한 분석결과도 제시하였다.

• 산업공학
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• 제10권2호
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• pp.41-50
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• 1997

This paper considers the reliability computation of the network with dependent components and a software system is developed for supporting the reliability analysis and improvement of the system reliability. At first, We propose the common cause failure and load sharing models as the typical models considering the dynamic behaviors of networks with dependent components. Secondly, the algorithm is proposed to obtain the network reliability and reliability importance of component. The software, Delphi, is used to develop the our reliability analysis system.