Cyber-physical power system(CPPS)has significantly improved the operational efficiency of power systems.However,cross-space cascading failures may occur due to the coupling characteristics,which poses a great threat t...Cyber-physical power system(CPPS)has significantly improved the operational efficiency of power systems.However,cross-space cascading failures may occur due to the coupling characteristics,which poses a great threat to the safety and reliability of CPPS,and there is an acute need to reduce the probability of these failures.Towards this end,this paper first proposes a cascading failure index to identify and quantify the importance of different information in the same class of communication services.On this basis,a joint improved risk-balanced service function chain routing strategy(SFC-RS)is proposed,which is modeled as a robust optimization problem and solved by column-and-constraint generation(C-CG)algorithm.Compared with the traditional shortest-path routing algorithm,the superiority of SFC-RS is verified in the IEEE 30-bus system.The results demonstrate that SFC-RS effectively mitigates the risk associated with information transmission in the network,enhances information transmission accessibility,and effectively limits communication disruption from becoming the cause of cross-space cascading failures.展开更多
AIM: To assess CD163 expression in plasma and peripheral blood and analyze its association with disease in acute-on-chronic hepatitis B liver failure (ACHBLF) patients. METHODS: A retrospective study was conducted fro...AIM: To assess CD163 expression in plasma and peripheral blood and analyze its association with disease in acute-on-chronic hepatitis B liver failure (ACHBLF) patients. METHODS: A retrospective study was conducted from January 1, 2011 to January 1, 2012. Forty patients with ACHBLF (mean age 44.48 ± 12.28 years, range 18-69 years), 40 patients with chronic hepatitis B (CHB) (mean age 39.45 ± 12.22 years, range 21-57 years) and 20 ageand sex-matched healthy controls (mean age 38.35 ± 11.97 years, range 28-60 years) were included in this study. Flow cytometry was used to analyze the frequency of CD163+ peripheral blood mononuclear cells (PBMCs) and surface protein expression of CD163. Real-time transcription-polymerase chain re-action was performed to assess relative CD163 mRNA levels in PBMCs. Plasma soluble CD163 (sCD163) levels were measured by enzyme-linked immunosorbent assay. Clinical variables were also recorded. Comparisons between groups were analyzed by Kruskal-Wallis H test and Mann-Whitney U test. Statistical analyses were performed using SPSS 15.0 software and a P value < 0.05 was considered statistically significant. RESULTS: Flow cytometry showed that the population of CD163+ PBMCs was significantly greater in ACHBLF patients than in CHB patients and healthy controls (47.9645% ± 17.1542%, 32.0975% ± 11.0215% vs 17.9460% ± 6.3618%, P < 0.0001). However, there were no significant differences in mean fluorescence intensity of CD163+ PBMCs within the three groups (27.4975 ± 11.3731, 25.8140 ± 10.0649 vs 20.5050 ± 6.2437, P = 0.0514). CD163 mRNA expression in ACHBLF patients was significantly increased compared with CHB patients and healthy controls (1.41 × 10 -2 ± 2.18 × 10 -2 , 5.10 × 10 -3 ± 3.61 × 10 -3 vs 37.0 × 10 -4 ± 3.55 × 10 -4 , P = 0.02). Plasma sCD163 levels in patients with ACHBLF were significantly increased compared with CHB patients and healthy controls (4706.2175 ± 1681.1096 ng/mL, 1089.7160 ± 736.8395 ng/mL vs 435.9562 ± 440.8329 ng/mL, P < 0.0001). In ACHBLF patients, plasma sCD163 levels were significantly positively associated with model for end-stage liver disease scores (r = 0.5075, P = 0.008), hepatitis B virus-DNA (r = 0.6827, P < 0.0001), and negatively associated with prothrombin activity (r = -0.3348, P = 0.0347), but had no correlation with total bilirubin (r = 0.2551, P = 0.1122). Furthermore, sCD163 was obviously elevated in non-surviving patients compared with surviving patients with ACHBLF (5344.9080 ± 1589.5199 ng/mL vs 3641.7333 ± 1264.5228 ng/mL, P = 0.0321). CONCLUSION: CD163 and sCD163 may be related to disease severity and prognosis in ACHBLF patients.展开更多
A new problem that classical statistical methods are incapable of solving is reliability modeling and assessment when multiple numerical control machine tools(NCMTs) reveal zero failures after a reliability test. Thus...A new problem that classical statistical methods are incapable of solving is reliability modeling and assessment when multiple numerical control machine tools(NCMTs) reveal zero failures after a reliability test. Thus, the zero-failure data form and corresponding Bayesian model are developed to solve the zero-failure problem of NCMTs, for which no previous suitable statistical model has been developed. An expert-judgment process that incorporates prior information is presented to solve the difficulty in obtaining reliable prior distributions of Weibull parameters. The equations for the posterior distribution of the parameter vector and the Markov chain Monte Carlo(MCMC) algorithm are derived to solve the difficulty of calculating high-dimensional integration and to obtain parameter estimators. The proposed method is applied to a real case; a corresponding programming code and trick are developed to implement an MCMC simulation in Win BUGS, and a mean time between failures(MTBF) of 1057.9 h is obtained. Given its ability to combine expert judgment, prior information, and data, the proposed reliability modeling and assessment method under the zero failure of NCMTs is validated.展开更多
To solve a real problem:how to calculate the reliability of a system with time-varying failure rates in industry systems,this paper studies a model for the load-sharing parallel system with time-varying failure rates,...To solve a real problem:how to calculate the reliability of a system with time-varying failure rates in industry systems,this paper studies a model for the load-sharing parallel system with time-varying failure rates,and obtains calculating formulas of reliability and availability of the system by solving differential equations.In this paper,the failure rates are expressed in polynomial configuration.The constant,linear and Weibull failure rate are in their special form.The polynomial failure rates provide flexibility in modeling the practical time-varying failure rates.展开更多
This paper deals with Bayesian inference and prediction problems of the Burr type XII distribution based on progressive first failure censored data. We consider the Bayesian inference under a squared error loss functi...This paper deals with Bayesian inference and prediction problems of the Burr type XII distribution based on progressive first failure censored data. We consider the Bayesian inference under a squared error loss function. We propose to apply Gibbs sampling procedure to draw Markov Chain Monte Carlo (MCMC) samples, and they have in turn, been used to compute the Bayes estimates with the help of importance sampling technique. We have performed a simulation study in order to compare the proposed Bayes estimators with the maximum likelihood estimators. We further consider two sample Bayes prediction to predicting future order statistics and upper record values from Burr type XII distribution based on progressive first failure censored data. The predictive densities are obtained and used to determine prediction intervals for unobserved order statistics and upper record values. A real life data set is used to illustrate the results derived.展开更多
Background: Amyloidosis is a disease characterized by the deposition of fibrillar proteins in tissues. The nature of the protein defines the type of amyloidosis. Cardiac involvement is most often secondary to deposits...Background: Amyloidosis is a disease characterized by the deposition of fibrillar proteins in tissues. The nature of the protein defines the type of amyloidosis. Cardiac involvement is most often secondary to deposits of transthyretin and immunoglobulin light chains. Treatment depends on the type of amyloidosis. Cardiac light chain amyloidosis is a medical emergency. Aim: To highlight the importance of an early diagnosis of cardiac light chain amyloidosis. Case Presentation: We report the case of an 88-year-old hypertensive female patient with sustained atrial fibrillation and recurrent heart failure, in whom echocardiography showed concentric left ventricle hypertrophy with mildly reduced left ventricle ejection fraction (LVEF) to 45%. Bone scintigraphy was normal. Serum analysis showed increased lambda free light chains. Accessory salivary gland biopsy revealed weak Kappa light chain staining and clear overexpression of lambda light chain deposits. The diagnosis of stage 3B cardiac amyloidosis secondary to lambda light chain myeloma was made. After a multidisciplinary meeting, it was decided to start treatment with DARATUMUMAB + LENALIDOMIDE. Patient’s general condition deteriorated with the occurrence of febrile pancytopenia. Chemotherapy was stopped and management was limited to comfort care until the patient’s death. Conclusion: Cardiac light-chain amyloidosis must be diagnosed early as it can be rapidly fatal.展开更多
现有安全稳定控制系统(简称稳控系统)的可靠性评估方法本质上属于静态建模,由于未能体现系统内各装置老化和检修等动态过程,在一定程度上影响了评估结果的准确性。为此,文中提出一种基于马尔可夫链蒙特卡洛(Markov chain Monte Carlo,MC...现有安全稳定控制系统(简称稳控系统)的可靠性评估方法本质上属于静态建模,由于未能体现系统内各装置老化和检修等动态过程,在一定程度上影响了评估结果的准确性。为此,文中提出一种基于马尔可夫链蒙特卡洛(Markov chain Monte Carlo,MCMC)的稳控系统动态可靠性评估方法。首先针对失效过程,构建四状态非齐次马尔可夫模型来模拟装置老化过程,并给出各状态评判方法;其次针对修复过程,分析不同检修策略对装置状态转移的影响以体现状态检修的差异性;最后考虑稳控装置状态转移过程的时序或条件相关性,对稳控系统可靠性进行动态建模。以实际稳控系统为例,仿真对比不同检修策略下的可靠性,并对模型参数进行灵敏度分析。评估结果表明,该方法可以求解稳控系统的时变可用度,用于指导稳控装置现场合理检修。展开更多
基金funded by the National Natural Science Foundation of China under Grant 52177074.
文摘Cyber-physical power system(CPPS)has significantly improved the operational efficiency of power systems.However,cross-space cascading failures may occur due to the coupling characteristics,which poses a great threat to the safety and reliability of CPPS,and there is an acute need to reduce the probability of these failures.Towards this end,this paper first proposes a cascading failure index to identify and quantify the importance of different information in the same class of communication services.On this basis,a joint improved risk-balanced service function chain routing strategy(SFC-RS)is proposed,which is modeled as a robust optimization problem and solved by column-and-constraint generation(C-CG)algorithm.Compared with the traditional shortest-path routing algorithm,the superiority of SFC-RS is verified in the IEEE 30-bus system.The results demonstrate that SFC-RS effectively mitigates the risk associated with information transmission in the network,enhances information transmission accessibility,and effectively limits communication disruption from becoming the cause of cross-space cascading failures.
基金Supported by Grants from Key Project of Chinese Ministry of Science and Technology, No. 2012ZX10002007 and No.2013ZX10002001National Natural Science Foundation of China, No. 81171579 and No. 81201287Natural Science Foundation of Shandong Province, No. ZR2010HM070 and No.ZR2010HQ040
文摘AIM: To assess CD163 expression in plasma and peripheral blood and analyze its association with disease in acute-on-chronic hepatitis B liver failure (ACHBLF) patients. METHODS: A retrospective study was conducted from January 1, 2011 to January 1, 2012. Forty patients with ACHBLF (mean age 44.48 ± 12.28 years, range 18-69 years), 40 patients with chronic hepatitis B (CHB) (mean age 39.45 ± 12.22 years, range 21-57 years) and 20 ageand sex-matched healthy controls (mean age 38.35 ± 11.97 years, range 28-60 years) were included in this study. Flow cytometry was used to analyze the frequency of CD163+ peripheral blood mononuclear cells (PBMCs) and surface protein expression of CD163. Real-time transcription-polymerase chain re-action was performed to assess relative CD163 mRNA levels in PBMCs. Plasma soluble CD163 (sCD163) levels were measured by enzyme-linked immunosorbent assay. Clinical variables were also recorded. Comparisons between groups were analyzed by Kruskal-Wallis H test and Mann-Whitney U test. Statistical analyses were performed using SPSS 15.0 software and a P value < 0.05 was considered statistically significant. RESULTS: Flow cytometry showed that the population of CD163+ PBMCs was significantly greater in ACHBLF patients than in CHB patients and healthy controls (47.9645% ± 17.1542%, 32.0975% ± 11.0215% vs 17.9460% ± 6.3618%, P < 0.0001). However, there were no significant differences in mean fluorescence intensity of CD163+ PBMCs within the three groups (27.4975 ± 11.3731, 25.8140 ± 10.0649 vs 20.5050 ± 6.2437, P = 0.0514). CD163 mRNA expression in ACHBLF patients was significantly increased compared with CHB patients and healthy controls (1.41 × 10 -2 ± 2.18 × 10 -2 , 5.10 × 10 -3 ± 3.61 × 10 -3 vs 37.0 × 10 -4 ± 3.55 × 10 -4 , P = 0.02). Plasma sCD163 levels in patients with ACHBLF were significantly increased compared with CHB patients and healthy controls (4706.2175 ± 1681.1096 ng/mL, 1089.7160 ± 736.8395 ng/mL vs 435.9562 ± 440.8329 ng/mL, P < 0.0001). In ACHBLF patients, plasma sCD163 levels were significantly positively associated with model for end-stage liver disease scores (r = 0.5075, P = 0.008), hepatitis B virus-DNA (r = 0.6827, P < 0.0001), and negatively associated with prothrombin activity (r = -0.3348, P = 0.0347), but had no correlation with total bilirubin (r = 0.2551, P = 0.1122). Furthermore, sCD163 was obviously elevated in non-surviving patients compared with surviving patients with ACHBLF (5344.9080 ± 1589.5199 ng/mL vs 3641.7333 ± 1264.5228 ng/mL, P = 0.0321). CONCLUSION: CD163 and sCD163 may be related to disease severity and prognosis in ACHBLF patients.
基金Project(2014ZX04014-011)supported by State Key Science&Technology Program of ChinaProject([2016]414)supported by the 13th Five-year Program of Education Department of Jilin Province,China
文摘A new problem that classical statistical methods are incapable of solving is reliability modeling and assessment when multiple numerical control machine tools(NCMTs) reveal zero failures after a reliability test. Thus, the zero-failure data form and corresponding Bayesian model are developed to solve the zero-failure problem of NCMTs, for which no previous suitable statistical model has been developed. An expert-judgment process that incorporates prior information is presented to solve the difficulty in obtaining reliable prior distributions of Weibull parameters. The equations for the posterior distribution of the parameter vector and the Markov chain Monte Carlo(MCMC) algorithm are derived to solve the difficulty of calculating high-dimensional integration and to obtain parameter estimators. The proposed method is applied to a real case; a corresponding programming code and trick are developed to implement an MCMC simulation in Win BUGS, and a mean time between failures(MTBF) of 1057.9 h is obtained. Given its ability to combine expert judgment, prior information, and data, the proposed reliability modeling and assessment method under the zero failure of NCMTs is validated.
文摘To solve a real problem:how to calculate the reliability of a system with time-varying failure rates in industry systems,this paper studies a model for the load-sharing parallel system with time-varying failure rates,and obtains calculating formulas of reliability and availability of the system by solving differential equations.In this paper,the failure rates are expressed in polynomial configuration.The constant,linear and Weibull failure rate are in their special form.The polynomial failure rates provide flexibility in modeling the practical time-varying failure rates.
文摘This paper deals with Bayesian inference and prediction problems of the Burr type XII distribution based on progressive first failure censored data. We consider the Bayesian inference under a squared error loss function. We propose to apply Gibbs sampling procedure to draw Markov Chain Monte Carlo (MCMC) samples, and they have in turn, been used to compute the Bayes estimates with the help of importance sampling technique. We have performed a simulation study in order to compare the proposed Bayes estimators with the maximum likelihood estimators. We further consider two sample Bayes prediction to predicting future order statistics and upper record values from Burr type XII distribution based on progressive first failure censored data. The predictive densities are obtained and used to determine prediction intervals for unobserved order statistics and upper record values. A real life data set is used to illustrate the results derived.
文摘Background: Amyloidosis is a disease characterized by the deposition of fibrillar proteins in tissues. The nature of the protein defines the type of amyloidosis. Cardiac involvement is most often secondary to deposits of transthyretin and immunoglobulin light chains. Treatment depends on the type of amyloidosis. Cardiac light chain amyloidosis is a medical emergency. Aim: To highlight the importance of an early diagnosis of cardiac light chain amyloidosis. Case Presentation: We report the case of an 88-year-old hypertensive female patient with sustained atrial fibrillation and recurrent heart failure, in whom echocardiography showed concentric left ventricle hypertrophy with mildly reduced left ventricle ejection fraction (LVEF) to 45%. Bone scintigraphy was normal. Serum analysis showed increased lambda free light chains. Accessory salivary gland biopsy revealed weak Kappa light chain staining and clear overexpression of lambda light chain deposits. The diagnosis of stage 3B cardiac amyloidosis secondary to lambda light chain myeloma was made. After a multidisciplinary meeting, it was decided to start treatment with DARATUMUMAB + LENALIDOMIDE. Patient’s general condition deteriorated with the occurrence of febrile pancytopenia. Chemotherapy was stopped and management was limited to comfort care until the patient’s death. Conclusion: Cardiac light-chain amyloidosis must be diagnosed early as it can be rapidly fatal.
文摘现有安全稳定控制系统(简称稳控系统)的可靠性评估方法本质上属于静态建模,由于未能体现系统内各装置老化和检修等动态过程,在一定程度上影响了评估结果的准确性。为此,文中提出一种基于马尔可夫链蒙特卡洛(Markov chain Monte Carlo,MCMC)的稳控系统动态可靠性评估方法。首先针对失效过程,构建四状态非齐次马尔可夫模型来模拟装置老化过程,并给出各状态评判方法;其次针对修复过程,分析不同检修策略对装置状态转移的影响以体现状态检修的差异性;最后考虑稳控装置状态转移过程的时序或条件相关性,对稳控系统可靠性进行动态建模。以实际稳控系统为例,仿真对比不同检修策略下的可靠性,并对模型参数进行灵敏度分析。评估结果表明,该方法可以求解稳控系统的时变可用度,用于指导稳控装置现场合理检修。
