The paper deals with systems suffered from gradual deterioration. To avoid functional failures and disastrous consequences, such systems should be monitored and preventively maintained. And to promote the maintenance ...The paper deals with systems suffered from gradual deterioration. To avoid functional failures and disastrous consequences, such systems should be monitored and preventively maintained. And to promote the maintenance effectiveness, an unequal time-interval maintenance policy was brought forward to substitute fixedinterval preventive maintenance strategy. At the same time, preventive and corrective maintenance actions are both assumed to be imperfect, and their impact on the system is expressed by the increment of failure rate. The case study shown that the unequal time-interval maintenance policy proposed in the paper is of help to promote the availability of the system.展开更多
This study addresses the existence, uniqueness, and comparison theorem forunbounded solutions of one-dimensional backward stochastic differential equations (BSDEs)with sub-quadratic generators, considering both finite...This study addresses the existence, uniqueness, and comparison theorem forunbounded solutions of one-dimensional backward stochastic differential equations (BSDEs)with sub-quadratic generators, considering both finite and infinite terminal times. Initially,we establish the existence of unbounded solutions for BSDEs where the generator gsatisfies a time-varying one-sided linear growth condition in the first unknown variable yand a time-varying sub-quadratic growth condition in the second unknown variable z. Next,the uniqueness and comparison theorems for unbounded solutions are proven under a timevaryingextended convexity assumption. These findings extend the results in [12] to thegeneral time-interval BSDEs. Finally, we propose and verify several sufficient conditionsfor ensuring uniqueness, utilizing innovative approaches applied for the first time, even inthe context of finite time-interval BSDEs.展开更多
In integrated energy systems(IESs),traditional fixed time-interval dispatching scheme is unable to adapt to the need of dynamic properties of the transient network,demand response characteristics,dispatching time scal...In integrated energy systems(IESs),traditional fixed time-interval dispatching scheme is unable to adapt to the need of dynamic properties of the transient network,demand response characteristics,dispatching time scales in energy subsystems and renewable power uncertainties.This scheme may easily result in uneconomic source-grid-load-storage operations in IES.In this paper,we propose a dispatching method for IES based on dynamic time-interval of model predictive control(MPC).We firstly build models for energy sub-systems and multi-energy loads in the power-gas-heat IES.Then,we develop an innovative optimization method leveraging trajectory deviation control,energy control,and cost control frameworks in MPC to handle the requirements and constraints over the timeinterval of dispatching.Finally,a dynamic programming algorithm is introduced to efficiently solve the proposed method.Experiments and simulation results prove the effectiveness of the method.展开更多
The process of extracting patterns that are frequent from supermarket datasets is a well known problem of data mining. Nowadays, we have many approaches to resolve the problem. Association rule mining is one among the...The process of extracting patterns that are frequent from supermarket datasets is a well known problem of data mining. Nowadays, we have many approaches to resolve the problem. Association rule mining is one among them. Supermarket data are usually temporal in nature as they record all the transactions in the supermarket, with the time of occurrence. An algorithm has been proposed to find frequent itemsets, taking the temporal attributes in supermarket dataset. The best part of the algorithm is that each frequent itemset extracted by it is associated with a list of time intervals in which it is frequent. Taking time of transactions as calendar dates, we may get various types of periodic patterns viz. yearly, quarterly, monthly, etc. If the time intervals associated with a periodic itemset are kept in a compact manner, it turns out to be a fuzzy time interval. Clustering of such patterns can be a useful data mining problem. In this paper, we put forward an agglomerative hierarchical clustering algorithm which is able to extracts clusters among such periodic itemsets. Here we take two similarity measures, one on the itemsets of the clusters and others on the corresponding fuzzy time intervals. The efficiency of the proposed method is demonstrated through experimentation on real datasets.展开更多
A major concern in modern smart-phones and hand-held devices is a way of mitigating the time interval error (TIE) perceived at high-speed digital transits along the traces of the circuit-board (rigid and or flexible) ...A major concern in modern smart-phones and hand-held devices is a way of mitigating the time interval error (TIE) perceived at high-speed digital transits along the traces of the circuit-board (rigid and or flexible) used in baseband infrastructures. Indicated here is a way of adopting a planar fractal inductor configuration to improvise the necessary time-delay in the transits of digital signal phase jitter and reduce the TIE. This paper addresses systematic design considerations on fractal inductor geometry commensurate with practical aspects of its implementation as delaylines in the high-speed digital transports at the baseband operations of smart-phone infrastructures. Experimental results obtained from a test module are presented to illustrate the efficacy of the design and acceptable delay performance of the test structure commensurate with the digital transports of interest.展开更多
Background:Radiotherapy following primary operation is strongly recommended for salivary gland carcinomas(SGCs)with adverse features.The interval between surgery and the initiation of radiotherapy(SRT)varied and a pro...Background:Radiotherapy following primary operation is strongly recommended for salivary gland carcinomas(SGCs)with adverse features.The interval between surgery and the initiation of radiotherapy(SRT)varied and a prolonged SRT may cause failure of cancer treatment.However,the association of SRT with survival is unclear in major SGCs.Methods:This retrospective study included a total of 346 patients who underwent radiotherapy after the pri-mary operation from Fudan University Shanghai Cancer Center from 2005 to 2020.The best cutoffvalue of the SRT was determined by the maximum log-rank statistic method.The primary endpoint of the study was over-all survival(OS).Correlations between variables and OS were conducted by the univariable analysis using the Log-rank method,and a multivariate Cox proportional hazards regression was performed to identify the indepen-dent prognostic factors associated with OS.The estimated survival rates were captured using the Kaplan-Meier method.Results:With a median follow-up time of 70.31 months,the estimated 5-year OS,LRFS,and DMFS were 83.3%,80.1%,and 75.9%,respectively.The cutoffvalue for SRT was 8.5 weeks,while age,T stage,N stage,perineural invasion(PNI),pathological aggression,chemotherapy,and SRT were associated with OS in the univariable analysis.The Cox regression analysis demonstrated that older age(P<0.001),T3-4 tumors(P=0.007),positive N stage(P<0.001),pathological aggression(P=0.014),and longer SRT(P=0.009)were independent prognostic factors for major SGCs.Using the stratification model,we observed that delay in the SRT was associated with worse OS(P=0.006)in the high-risk group,whereas no significant difference was observed in the low-risk subgroup(P=0.61).Conclusions:The delay in the initiation of postoperative radiotherapy may be a prognostic factor for patients with major SGCs.It was suggested that radiotherapy should be delivered within 8.5 weeks following the operation,especially for patients with≥2 risk factors,including older age,high pathological aggression,T3-4 tumors,and positive N stage.展开更多
文摘The paper deals with systems suffered from gradual deterioration. To avoid functional failures and disastrous consequences, such systems should be monitored and preventively maintained. And to promote the maintenance effectiveness, an unequal time-interval maintenance policy was brought forward to substitute fixedinterval preventive maintenance strategy. At the same time, preventive and corrective maintenance actions are both assumed to be imperfect, and their impact on the system is expressed by the increment of failure rate. The case study shown that the unequal time-interval maintenance policy proposed in the paper is of help to promote the availability of the system.
文摘This study addresses the existence, uniqueness, and comparison theorem forunbounded solutions of one-dimensional backward stochastic differential equations (BSDEs)with sub-quadratic generators, considering both finite and infinite terminal times. Initially,we establish the existence of unbounded solutions for BSDEs where the generator gsatisfies a time-varying one-sided linear growth condition in the first unknown variable yand a time-varying sub-quadratic growth condition in the second unknown variable z. Next,the uniqueness and comparison theorems for unbounded solutions are proven under a timevaryingextended convexity assumption. These findings extend the results in [12] to thegeneral time-interval BSDEs. Finally, we propose and verify several sufficient conditionsfor ensuring uniqueness, utilizing innovative approaches applied for the first time, even inthe context of finite time-interval BSDEs.
基金supported in part by National Key R&D Program of China(No.2018YFB0905000)National Natural Science Foundation of China(No.61873121)Science and Technology Project of State Grid Corporation of China(No.SGTJDK00DWJS1800232)
文摘In integrated energy systems(IESs),traditional fixed time-interval dispatching scheme is unable to adapt to the need of dynamic properties of the transient network,demand response characteristics,dispatching time scales in energy subsystems and renewable power uncertainties.This scheme may easily result in uneconomic source-grid-load-storage operations in IES.In this paper,we propose a dispatching method for IES based on dynamic time-interval of model predictive control(MPC).We firstly build models for energy sub-systems and multi-energy loads in the power-gas-heat IES.Then,we develop an innovative optimization method leveraging trajectory deviation control,energy control,and cost control frameworks in MPC to handle the requirements and constraints over the timeinterval of dispatching.Finally,a dynamic programming algorithm is introduced to efficiently solve the proposed method.Experiments and simulation results prove the effectiveness of the method.
文摘The process of extracting patterns that are frequent from supermarket datasets is a well known problem of data mining. Nowadays, we have many approaches to resolve the problem. Association rule mining is one among them. Supermarket data are usually temporal in nature as they record all the transactions in the supermarket, with the time of occurrence. An algorithm has been proposed to find frequent itemsets, taking the temporal attributes in supermarket dataset. The best part of the algorithm is that each frequent itemset extracted by it is associated with a list of time intervals in which it is frequent. Taking time of transactions as calendar dates, we may get various types of periodic patterns viz. yearly, quarterly, monthly, etc. If the time intervals associated with a periodic itemset are kept in a compact manner, it turns out to be a fuzzy time interval. Clustering of such patterns can be a useful data mining problem. In this paper, we put forward an agglomerative hierarchical clustering algorithm which is able to extracts clusters among such periodic itemsets. Here we take two similarity measures, one on the itemsets of the clusters and others on the corresponding fuzzy time intervals. The efficiency of the proposed method is demonstrated through experimentation on real datasets.
文摘A major concern in modern smart-phones and hand-held devices is a way of mitigating the time interval error (TIE) perceived at high-speed digital transits along the traces of the circuit-board (rigid and or flexible) used in baseband infrastructures. Indicated here is a way of adopting a planar fractal inductor configuration to improvise the necessary time-delay in the transits of digital signal phase jitter and reduce the TIE. This paper addresses systematic design considerations on fractal inductor geometry commensurate with practical aspects of its implementation as delaylines in the high-speed digital transports at the baseband operations of smart-phone infrastructures. Experimental results obtained from a test module are presented to illustrate the efficacy of the design and acceptable delay performance of the test structure commensurate with the digital transports of interest.
文摘Background:Radiotherapy following primary operation is strongly recommended for salivary gland carcinomas(SGCs)with adverse features.The interval between surgery and the initiation of radiotherapy(SRT)varied and a prolonged SRT may cause failure of cancer treatment.However,the association of SRT with survival is unclear in major SGCs.Methods:This retrospective study included a total of 346 patients who underwent radiotherapy after the pri-mary operation from Fudan University Shanghai Cancer Center from 2005 to 2020.The best cutoffvalue of the SRT was determined by the maximum log-rank statistic method.The primary endpoint of the study was over-all survival(OS).Correlations between variables and OS were conducted by the univariable analysis using the Log-rank method,and a multivariate Cox proportional hazards regression was performed to identify the indepen-dent prognostic factors associated with OS.The estimated survival rates were captured using the Kaplan-Meier method.Results:With a median follow-up time of 70.31 months,the estimated 5-year OS,LRFS,and DMFS were 83.3%,80.1%,and 75.9%,respectively.The cutoffvalue for SRT was 8.5 weeks,while age,T stage,N stage,perineural invasion(PNI),pathological aggression,chemotherapy,and SRT were associated with OS in the univariable analysis.The Cox regression analysis demonstrated that older age(P<0.001),T3-4 tumors(P=0.007),positive N stage(P<0.001),pathological aggression(P=0.014),and longer SRT(P=0.009)were independent prognostic factors for major SGCs.Using the stratification model,we observed that delay in the SRT was associated with worse OS(P=0.006)in the high-risk group,whereas no significant difference was observed in the low-risk subgroup(P=0.61).Conclusions:The delay in the initiation of postoperative radiotherapy may be a prognostic factor for patients with major SGCs.It was suggested that radiotherapy should be delivered within 8.5 weeks following the operation,especially for patients with≥2 risk factors,including older age,high pathological aggression,T3-4 tumors,and positive N stage.
