A cost minimisation model for system reliability allocation

2019 ◽  
Vol 36 (9) ◽  
pp. 1620-1643 ◽  
Author(s):  
Omkarprasad S. Vaidya ◽  
L. Ganapathy ◽  
Sushil Kumar
Keyword(s):  
Optimization Problem ◽  
Cost Optimization ◽  
Optimal Solution ◽  
System Component ◽  
Lagrangian Multiplier ◽  
Step Size ◽  
Exponential Relationship ◽  
Content Type ◽  
In Series ◽  
The Cost

Purpose The purpose of this paper is to consider a nonlinear problem of minimizing the cost of providing reliable systems. The authors assume that the system consists of several components in series, and for each such component, the cost of the component increases exponentially with its reliability. Design/methodology/approach In order to solve this nonlinear optimization problem, the authors propose two approaches. The first approach is based on the concept of adjusting the reliability of a pair of components to minimize the cost of the system. The authors call this procedure as reliability adjustment routine (RAR). Proofs of optimality and convergence for the proposed model are also provided. The second approach solves the problem by using a Lagrangian multiplier. A procedure is developed to obtain the maximum step size to achieve the desired optimal solution in minimum iterations. Proposed approaches are efficient and give exact solutions. Findings Proposed methods enable a decision maker to allocate reliability to the components in series while minimizing the total cost of the system. The developed procedures are illustrated using a numerical example. Although an exponential relationship between the component cost and reliability is assumed, this can be extended to various other nonlinear distributions. Originality/value This cost optimization problem, subject to system component reliability values, assumes the near practical nonlinear pattern of cost vs reliability. Such problems are complex to solve. The authors provide a unique approach called RAR to solve such convoluted problems. The authors also provide an approach to solve such problems by using a Lagrangian multiplier method. Various proofs have been worked out to substantiate the work.

The cost competitiveness, competitiveness and sustainability of the hospitality industry in India

2016 ◽  
Vol 8 (4) ◽  
pp. 432-443 ◽  
Author(s):  
Madhu Vij
Keyword(s):  
Hospitality Industry ◽  
Cost Optimization ◽  
Cost Effective ◽  
Comprehensive Treatment ◽  
Global Level ◽  
Content Type ◽  
Present Context ◽  
Cost Competitiveness ◽  
Internal Operations ◽  
The Cost

Purpose This study aims to provide a comprehensive treatment of the various issues surrounding the concept of the cost competitiveness, competitiveness and sustainability of the hospitality industry. We also investigate how innovations in the Indian hospitality industry can optimize costs without compromising the quality of the product or the services offered. Design/methodology/approach The methodology used is mainly survey-based with the use of both structured and unstructured questionnaires. In addition, some interviews were conducted with policy-makers and academics to explore from their perspectives what might be the innovations and sustainability issues in the next decade. Findings The paper helps to identify the essential aspects of cost competitiveness, competitiveness and sustainability in the hospitality industry and to better understand if cost optimization can be accomplished simply by realigning process or cost. These issues have become very important in India in the present context of globalization. Practical implications With growing competition on a global level, the hospitality industry needs to proactively manage its internal operations and focus on reducing costs and raising service quality. In this context, the paper helps to reveal sustainable cost effective practices that are geared to today’s competitive environment. Originality/value The inspiration to write this paper arises from the recent global economic slowdown and the fact that the hospitality industry is confronted with growing competition on a global level. This study highlights how value can be created for customers by applying suitable strategies.

Representation of replacement rules in the form of a matrix

2016 ◽  
Vol 22 (2) ◽  
pp. 164-179
Author(s):  
Sergey Golovin
Keyword(s):  
Mathematical Models ◽  
Cost Structure ◽  
Verbal Description ◽  
System Component ◽  
Content Type ◽  
Maintenance Program ◽  
Repair Costs ◽  
System Components ◽  
The Matrix ◽  
The Cost

Purpose – The purpose of this paper is to represent replacement policies (rules) in the form of a matrix. Visualization of replacement rules is useful for maintenance records. Matrix representation is more effective than the verbal description usually provided, as it allows better understanding of the specifics of the different replacement rules without careful research of their mathematical models. Design/methodology/approach – This approach employs mathematical models to investigate the simple conditions (requirements) for replacement of system component with illustrative examples. When comparing the different replacement rules a cost structure is applied to takes into account the nature and technology of disassembly assembly actions for the repair unit. Findings – Representation of replacement rules in the matrix form is useful when describing planned replacement models, opportunity replacement models, group replacement models and others, as well as computer modeling of the renewal process. Forming simple conditions for the replacement of system components ensures the total average repair cost is minimized. These conditions can be applied in the early stages of creating a maintenance program for the machine. Practical implications – Replacement matrices can be specified in a technical manual for maintenance of machines to achieve reliable operation and to reduce repair costs. Replacement matrices can be put into practical use for maintenance records and may be included in the maintenance procedures library of CMMSs. Developed in the paper, the replacement matrix, the conditions for replacement of system components and the cost structure will help engineers to make decisions at the time of repair for assembly units. Originality/value – Proposed in the paper is a new approach to the visualization of the replacement rules and cost structure which simplifies the analysis of options for repair actions. The proposed technique contributes to the record of maintenance actions and the decision making process for replacement.

Automated layout design of multi-span reinforced concrete beams using charged system search algorithm

2018 ◽  
Vol 35 (3) ◽  
pp. 1402-1413 ◽  
Author(s):  
Mehmet Eren Uz ◽  
Pezhman Sharafi ◽  
Mahya Askarian ◽  
Weiqing Fu ◽  
Chunmei Zhang
Keyword(s):  
Reinforced Concrete ◽  
Optimization Problem ◽  
Concrete Beams ◽  
Cost Optimization ◽  
Layout Design ◽  
Content Type ◽  
Charged System Search ◽  
Automated Method ◽  
Charged System ◽  
Geometric Layout

Purpose The preliminary layout design of structures impacts upon the entire design process and, consequently, the total cost. The purpose of this paper is to select the most economical layouts that satisfy structural and architectural requirements, while considering the reciprocal effects of cost factors and layout variables at the preliminary stages of design. Design/methodology/approach This paper presents an automated method for cost optimization of geometric layout design of multi-span reinforced concrete (RC) beams subjected to dynamic loading by using the charged system search (CSS) algorithm. First, a novel cost optimization approach for geometric layout problems is introduced, in which both cost parameters and dynamic responses are considered in the preliminary layout design of beams. The proposed structural optimization problem with constraints on the static and dynamic equilibrium, architectural dimensions and structural action effects is solved using the CSS algorithm. Findings The proposed CSS algorithm for solving the cost optimization problem can be easily used for optimizing the span lengths and is also capable of working with various cost functions. The presented examples show that the proposed algorithm using the new cost optimization function provides satisfactory results and can result in over 7 per cent cost saving. Originality/value This is an original paper proposing a novel methodology for preliminary layout design of concrete beams.

Optimal control of nonlinear systems with dynamic programming

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Isaac Tawiah ◽  
Yinglei Song
Keyword(s):  
Optimal Control ◽  
Optimization Problem ◽  
Optimal Control Problems ◽  
Optimal Solution ◽  
Functional Approach ◽  
Equality Constraints ◽  
Control Problems ◽  
Iterative Approach ◽  
Simulation Results ◽  
The Cost

Abstract In this paper, a generalized technique for solving a class of nonlinear optimal control problems is proposed. The optimization problem is formulated based on the cost-to-go functional approach and the optimal solution can be obtained by Bellman’s technique. Specifically, a continuous nonlinear system is first discretized and a set of equality constraints can be obtained from the discretization. We show that, under a certain condition, the optimal solution of a problem in this class can be approximated by a solution of the set of equality constraints within any precision and the system is guaranteed to be stable under a control signal obtained from the solution. An iterative approach is then applied to numerically solve the set of equality constraints. The technique is tested on a nonlinear control problem from the class and simulation results show that the approach is not only effective but also leads to a fast convergence and accurate optimal solution.

scholarly journals Cost Optimization in the SIS Model of Infectious Disease with Treatment

2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Steven Marc Goldman ◽  
James Lightwood
Keyword(s):  
Infectious Disease ◽  
Optimization Problem ◽  
Cost Optimization ◽  
Rational Behavior ◽  
Present Value ◽  
Sis Model ◽  
Optimal Program ◽  
Private Behavior ◽  
Long Run ◽  
The Cost

Abstract We consider the intertemporal social optimization problem of minimizing the present value of the costs incurred from both disease and treatment. Though the analysis is complicated by the analytical failure of concavity, we are able to substantially characterize both the long run equilibria and the adjustment paths. The cost minimizing program is shown to exhibit decreased levels of treatment at higher disease levels. The socially optimal program is compared to individually rational behavior and the inefficiencies in private behavior from the infection externality are shown to cause increases in the equilibrium rate of infection.

Cost assessment of complex repairable system consisting two subsystems in series configuration using Gumbel Hougaard family copula

2019 ◽  
Vol 36 (10) ◽  
pp. 1683-1698 ◽  
Author(s):  
Abdul Kareem Lado ◽  
V.V. Singh
Keyword(s):  
Joint Probability ◽  
Industrial Sector ◽  
Joint Probability Distribution ◽  
Cost Assessment ◽  
Social Implication ◽  
Content Type ◽  
In Series ◽  
Series Configuration ◽  
Parallel Configuration ◽  
The Cost

Purpose The purpose of this paper is to covenant with the cost assessment of a complex repairable system, consisting of two subsystems (Subsystem 1 and Subsystem 2) connected in series configuration and being operated by a human operator. Each subsystem has two identical units in parallel configuration and has different types of failure and two types of repairs (general repair and copula repair). Through the transition diagram, the system of first-order partial differential equations is derived and solved using a supplementary variable technique, Laplace transforms. All failures are assumed to follow exponential distribution, whereas repairs follow two types of distributions that are general and Gumbel–Hougaard family copula. In this paper, explicit expressions for reliability, availability, mean time to failure (MTTF) and cost analysis functions have been obtained. In this paper, two types of repairs (copula repair and general repair) have been studied, and it has been concluded that copula repair is more reliable as compared to general repair. Some computations are taken as particular case by evaluating: reliability, availability, MTTF and cost analysis, so as to capture the effect of both failure and repair rates to reliability measures. The results have been shown in tables and graphs. The convincing part has been discussed in last section of this study. Design/methodology/approach This paper is focused on the cost assessment of a system consisting two subsystem series configuration. Each subsystem has two identical units in parallel configuration. The performance of the system has been analyzed by supplementary variable techniques and Laplace transforms. Various measures of the reliability have been discussed by evaluations. Software called Maple 13 is used for computations. Findings In this research paper, the authors have evaluated the operational cost and incurred profit of the system together with other reliability measures for various situations and different types of failures and two types of repairs using Gumbel–Hougaard family copula distribution. Research limitations/implications The present research focuses on the series and parallel configured complex systems that is used everywhere in industry and other sectors. The authors main aim is to claim that repair through the joint probability distribution copula is far better than general repair. Copula repair for a completely failed system is more beneficial for industrial system operations that will increase profit to the industrial sector. Practical implications The authors have observed that when repair follows general distribution the values of reliability obtained of the system are less compared to the those obtained when the authors apply copula repair, a joint probability distribution. It is a clear implication for industrial sector and organization to use the policy for a better generate revenue. Social implications According to the best of authors’ knowledge, there is no social implication as this study is meant for reliability section. The study in management and case study matters is considered to have social implication. Originality/value This research is the original work of authors. Nothing has been copied from any paper or book. The references are cited according to the relevance of study.

Business Cost Budgets

2012 ◽  
Vol 3 (3) ◽  
pp. 49-64 ◽  
Author(s):  
Axel Kieninger ◽  
Gerhard Satzger ◽  
Detlef Straeten ◽  
Björn Schmitz ◽  
Dian Baltadzhiev
Keyword(s):  
Service Quality ◽  
Optimization Problem ◽  
Service Level Agreement ◽  
Optimal Solution ◽  
Service Level ◽  
Service Level Agreements ◽  
Additional Information ◽  
Quality Aspects ◽  
The Cost ◽  
Business Cost

In this work the authors address an IT service customer’s challenge of selecting the cost-optimal service level agreement among different options offered by an external provider. They model the customer’s optimization problem at distinctive levels of detail with regard to the description of service quality aspects. At each level of detail they explicitly consider the potential negative monetary impact of different service quality levels on a customer’s business process – reflected via the concept of “business cost.” First, they analyze which information a customer typically bases service level agreement decisions upon today and elaborate on the question which additional information a rational customer would need to take a well-founded decision. Second, the authors define a set of concepts that a customer should consider when selecting service level agreements. Third, the authors apply these concepts to develop a “business cost budget method” that enables a customer to compare multiple service level agreements and to select the cost-optimal solution of its optimization problem – assuming customer and provider to collaborate. Introducing this approach, they suggest that both parties jointly define “business cost budgets” as an additional kind of service indicator describing service quality’s adverse business impact instead of only service quality.

Supplier selection problem in IoT solutions

2019 ◽  
Vol 15 (1) ◽  
pp. 16-19 ◽  
Author(s):  
Sonal Agarwal ◽  
Vidushi Sharma ◽  
Anuradha Pughat
Keyword(s):  
Supply Chain ◽  
Unit Cost ◽  
Cost Optimization ◽  
Vendor Selection ◽  
Strategic Decisions ◽  
Product Cost ◽  
Content Type ◽  
Cost Constraints ◽  
The Right ◽  
The Cost

Purpose The use of Internet of Things (IoT) and networks has built a potential impact on the product cost and time in a company’s manufacturing process. These IoT solutions provide end-to-end visibility and faster introduction of merchandise and supplier in the market. The main aim of this research paper is to supply products with improved quality and cheaper price, whereas the rising response and quality of the client service. Design/methodology/approach This paper designs and develops two cases for selecting the most efficient vendor while keeping in mind the profit and cost constraints in optimization. Findings Outsourcing is a vital parameter to cut back the price and maximize the profit of the manufacturer. Therefore, the integration of supply chain with IoT can provide a solution to the cost optimization and supplier/vendor selection problems in supply chain management. Research limitations/implications The results show that the models are quite realistic and can help the IoT-based manufacturing units to make strategic decisions regarding product manufacturing and distribution. Practical implications The authors can further extend the model to derive the retailer’s profit function and develop the end product cost to the consumers and hence make it a n-level multi-vendor selection model for IoT-based systems. Originality/value The right choice of vendor for IoT-enabled business is a crucial concern. In this paper, the authors designed and developed multi-vendor models with in-house production and outsourcing decisions to meet the demand along with the vendor selection. The variable demands and designed variable unit cost function and batch order are set to make vendor selection more realistic.

Multiobjective optimization of compensation networks for wireless power transfer systems

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Manuele Bertoluzzo ◽  
Paolo Di Barba ◽  
Michele Forzan ◽  
Maria Evelina Mognaschi ◽  
Elisabetta Sieni
Keyword(s):  
Frequency Response ◽  
Optimization Problem ◽  
Optimization Problems ◽  
Optimal Solution ◽  
Wireless Power Transfer ◽  
Power Transfer ◽  
Wireless Power ◽  
Nsga Ii ◽  
Content Type ◽  
Starting Point

Purpose The purpose of this paper is to show how the EStra-Many method works on optimization problems characterized by high-dimensionality of the objective space. Moreover, a comparison with a more classical approach (a constrained bi-objective problem solved by means of NSGA-II) is done. Design/methodology/approach The six reactances of a compensation network (CN) for a wireless power transfer system (WPTS) are synthesized by means of an automated optimal design. In particular, an evolutionary algorithm EStra-Many coupled with a sorting strategy has been applied to an optimization problem with four objective functions (OFs). To assess the obtained results, a classical genetic algorithm NSGA-II has been run on a bi-objective problem, constrained by two functions, and the solutions have been analyzed and compared with the ones obtained by EStra-Many. Findings The proposed EStra-Many method identified a solution (CN synthesis) that enhances the WPTS, considering all the four OFs. In particular, to assess the synthesized CN, the Bode diagram of the frequency response and a circuital simulation were evaluated a posteriori; they showed good performance of the CN, with smooth response and without unwanted oscillations when fed by a square wave signal with offset. The EStra-Many method has been able to find a good solution among all the feasible solutions, showing potentiality also for other fields of research, in fact, a solution nondominated with respect to the starting point has been identified. From the methodological viewpoint, the main finding is a new formulation of the many-objective optimization problem based on the concept of degree of conflict, which gives rise to an implementation free from hierarchical weights. Originality/value The new approach EStra-Many used in this paper showed to properly find an optimal solution, trading-off multiple objectives. The compensation network so synthesized by the proposed method showed good properties in terms of frequency response and robustness. The proposed method, able to deal effectively with four OFs, could be applied to solve problems with a higher number of OFs in a variety of applications because of its generality.

On the Accelerated Convergence of the Decentralized Event-triggered Algorithm for Convex Optimization

2021 ◽  
Vol 30 (01) ◽  
pp. 2140003
Author(s):  
Keke Zhang ◽  
Jiang Xiong ◽  
Xiangguang Dai
Keyword(s):  
Cost Function ◽  
Optimal Solution ◽  
Linear Convergence ◽  
Step Size ◽  
Undirected Network ◽  
Momentum Coefficient ◽  
Convex Cost ◽  
Local Convex ◽  
The Cost ◽  
Event Triggered

This article considers a problem of solving the optimal solution of the sum of locally convex cost functions over an undirected network. Each local convex cost function in the network is accessed only by each unit. To be able to reduce the amount of computation and get the desired result in an accelerated way, we put forward a fresh accelerated decentralized event-triggered algorithm, named as A-DETA, for the optimization problem. A-DETA combines gradient tracking and two momentum accelerated terms, adopts nonuniform step-sizes and emphasizes that each unit interacts with neighboring units independently only at the sampling time triggered by the event. On the premise of assuming the smoothness and strong convexity of the cost function, it is proved that A-DETA can obtain the exact optimal solution linearly in the event of sufficiently small positive step-size and momentum coefficient. Moreover, an explicit linear convergence speed is definitely shown. Finally, extensive simulation example validates the usability of A-DETA.

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