Theory and analysis of consecutive-k-out-of-n:G systems reliability

This study introduces the concept of consecutive-k-out-of-n:G systems. Twelve theorems are derived to establish and support the basic theory of consecutive-k-out-of-n:G systems reliability;Applying the theorems, one can evaluate the reliability of linear consecutive-k-out-of-n:G systems and the reliability of circular consecutive-k-out-of-n:G systems, respectively. One can determine the reliability importance of components that indicates which component deserves the most additional investigation and development to improve the overall system reliability at the minimum effort. The study also provides a way to apply the methods for consecutive-k-out-of-n:F systems to consecutive-k-out-of-n:G systems. There exist n!/2 possible designs for a linear consecutive-k-out-of-n system, and (n - 1)!/2 possible designs for a circular consecutive-k-out-of-n system. A problem of interest is to find the design (or configuration) which maximizes the overall system reliability. Some aspects of the optimal design of consecutive-k-out-of-n systems have been investigated, and some necessary conditions for the optimal design of consecutive-k-out-of-n:G systems and consecutive-k-out-of-n:F systems have been derived, respectively. Further, a sufficient condition for the optimal configuration of a linear consecutive-k-out-of-n:G system with restriction of n ≤ 2k has been presented;Reliability evaluations are mainly based on recursive approaches. If all components are equally reliable and the system size n is less than or equal to 3k, the closed formulas are provided to evaluate the system reliability directly for both linear and circular systems. Bounds on the reliability of consecutive-k-out-of-n systems are studied since it is, sometimes, sufficient to know the bounds on the system reliability. An approximation to the reliability of a large linear consecutive-k-out-of-n:G system with equally reliable components is proposed and a suggestion in this situation is given

Synthesis and Performance Analysis of Network Topology using Graph Theory

In this work, the peculiarities of network topology have been explored to evolve techniques for the solution of practical problems which manifest in the form of graphs.  They also give insight into the scope and possible areas for improvement of existing networks and as well the cost implication of incorporating efficiciency factors into new designs. The shortest route algorithm was applied in defining the topology that maximizes reliability during resource transmission. The algorithm was implemented using TORA Software on an Excel platform. Key words: topology, graphs, vertices, nodes, edges, telecommunication networ

Information Technology of Software Architecture Structural Synthesis of Information System

Information technology of information system software architecture structural synthesis is proposed. It is used for evolutionary models of the software lifecycle, which provides configuration and formation of software to control the realization and recovery of computing processes in parallel and distributed computing resources structures. The technology is applied in the framework of the software requirements analysis, design of architecture, design and integration of software. Method of combining vertices for multilevel graph model of software architecture and automata-based method of checking performance limitations to software are based on the advanced graph model of software architecture. These methods are proposed in the framework of information technology and allow forming a rational structure of the program, as well as checking for compliance with the functional and non-functional requirements of the end user.The essence of proposed information technology is in displaying of the customer's requirements in the current version of the graph model of program complex structure and providing a reconfiguration of the system modules. This process is based on the analysis and processing of the graph model, software module specifications, formation of software structure in accordance with the graph model, software verification and its compilation

Statistical reliability assessment for small sample of failure data of dumper diesel engines based on power law process and maximum likelihood estimation

Dumpers or dump trucks are used all over the world to move overburden from many opencast mines. Diesel engines are the main driving force behind the trucks. The frequency of damage due to the failure of diesel engines is enormous. Therefore, efforts are necessary to analyze failure to reduce the downtime periods. A detailed analysis of engine failure at the subsystem level needs to be done. Reliability analysis and maintenance planning remain the norm in this regard. The obstacle faced while analysing the reliability of dumpers was the availability of a large number of data failures. In this paper, this issue is addressed by using Common Beta Hypothesis test and Meta-analysis test. The engine is divided into five subsystems. The result shows that all five subsystems pass the CBH test and Meta-analysis test. Accordingly, the failure data is grouped. The trend test of grouped failure data shows that the Failure data of two subsystems follows the independent and identically distributed characteristics while the remaining three do not follow it. The reliability is estimated for all five subsystems. Finally, fuel supply subsystems show the highest reliability while the lowest value is seen for self-starting subsystems.The authors are grateful to FCT—Fundação para a Ciência e Tecnologia who financially supported this work through the RD Units Project Scope: UIDP/04077/2020 and UIDB/04077/2020

Reliable fault-tolerant model predictive control of drinking water transport networks

This paper proposes a reliable fault-tolerant model predictive control applied to drinking water transport networks. After a fault has occurred, the predictive controller should be redesigned to cope with the fault effect. Before starting to apply the fault-tolerant control strategy, it should be evaluated whether the predictive controller will be able to continue operating after the fault appearance. This is done by means of a structural analysis to determine loss of controllability after the fault complemented with feasibility analysis of the optimization problem related to the predictive controller design, so as to consider the fault effect in actuator constraints. Moreover, by evaluating the admissibility of the different actuator-fault configurations, critical actuators regarding fault tolerance can be identified considering structural, feasibility, performance and reliability analyses. On the other hand, the proposed approach allows a degradation analysis of the system to be performed. As a result of these analyses, the predictive controller design can be modified by adapting constraints such that the best achievable performance with some pre-established level of reliability will be achieved. The proposed approach is tested on the Barcelona drinking water transport network.Postprint (author's final draft

A stream processing framework based on linked data for information collaborating of regional energy networks

© 2005-2012 IEEE. Coordinating of energy networks to form a city-level multidimensional integrated energy system becomes a new trend in Energy Internet (EI). The collaborating in the information layer is a core issue to achieve smart integration. However, the heterogeneity of multiagent data, the volatility of components, and the real-time analysis requirement in EI bring significant challenges. To solve these problems, in this article we propose a stream processing framework based on linked data for information collaboration among multiple energy networks. The framework provides a universal data representation based on linked data and semantic relation discovery approach to model and semantically fuse heterogeneous data. Semantics-based information transmission contracts and channels are automatically generated to adapt to structural changes in EI. A multimodel-based dynamic adjusting stream processing is implemented using data semantics. A real-world case study is implemented to demonstrate the adaptability, feasibility, and flexibility of the proposed framework

Economic health-aware LPV-MPC based on system reliability assessment for water transport network

This paper proposes a health-aware control approach for drinking water transport networks. This approach is based on an economic model predictive control (MPC) that considers an additional goal with the aim of extending the components and system reliability. The components and system reliability are incorporated into the MPC model using a Linear Parameter Varying (LPV) modeling approach. The MPC controller uses additionally an economic objective function that determines the optimal filling/emptying sequence of the tanks considering that electricity price varies between day and night and that the demand also follows a 24-h repetitive pattern. The proposed LPV-MPC control approach allows considering the model nonlinearities by embedding them in the parameters. The values of these varying parameters are updated at each iteration taking into account the new values of the scheduling variables. In this way, the optimization problem associated with the MPC problem is solved by means of Quadratic Programming (QP) to avoid the use of nonlinear programming. This iterative approach reduces the computational load compared to the solution of a nonlinear optimization problem. A case study based on the Barcelona water transport network is used for assessing the proposed approach performance.Peer ReviewedPostprint (published version

Contingency-Constrained Unit Commitment with Post-Contingency Corrective Recourse

We consider the problem of minimizing costs in the generation unit commitment problem, a cornerstone in electric power system operations, while enforcing an N-k-e reliability criterion. This reliability criterion is a generalization of the well-known $N$-$k$ criterion, and dictates that at least $(1-e_ j)$ fraction of the total system demand must be met following the failures of $k$ or fewer system components. We refer to this problem as the Contingency-Constrained Unit Commitment problem, or CCUC. We present a mixed-integer programming formulation of the CCUC that accounts for both transmission and generation element failures. We propose novel cutting plane algorithms that avoid the need to explicitly consider an exponential number of contingencies. Computational studies are performed on several IEEE test systems and a simplified model of the Western US interconnection network, which demonstrate the effectiveness of our proposed methods relative to current state-of-the-art

Reliability and cost: A sensitivity analysis

In the design phase of a system, how a design engineer or manager choose between a subsystem with .990 reliability and a more costly subsystem with .995 reliability is examined, along with the justification of the increased cost. High reliability is not necessarily an end in itself but may be desirable in order to reduce the expected cost due to subsystem failure. However, this may not be the wisest use of funds since the expected cost due to subsystem failure is not the only cost involved. The subsystem itself may be very costly. The cost of the subsystem nor the expected cost due to subsystem failure should not be considered separately but the total of the two costs should be maximized, i.e., the total of the cost of the subsystem plus the expected cost due to subsystem failure