Papers by Jose Ramirez-marquez
For power industry systems, reliability is related to the ability of the system to provide an ade... more For power industry systems, reliability is related to the ability of the system to provide an adequate supply of electrical energy (2-5). However, reliability related measures are fundamentally different to those used in traditional reliability practice. System reliability is related to the probability that a product/service will operate properly for a specified period of time under the design operating conditions
Computers & Industrial Engineering, 2015
ABSTRACT Rapid cardiac defibrillation is an essential link in the "Chain of Survival&... more ABSTRACT Rapid cardiac defibrillation is an essential link in the "Chain of Survival" for Sudden Cardiac Arrest (SCA) victims. Bystander access to publicly available Automated External Defibrillators (AEDs) can provide the necessary care to victims prior to arrival of emergency responders. Use of public-access AEDs has shown promising results in decreasing collapse-to-shock times among SCA patients which is associated with improved patient outcomes. The purpose of this study is to develop a method for generating optimal placement plans of public-access AEDs. These plans can be used for deployment in urban environments. Previous studies suggest targeting areas with concentrations of high risk populations or high foot-traffic. Most recently, studies have begun to implement mathematical optimization based on historic incidences. The novelty of this study lies in the use of an evolutionary, multi-objective optimization for maximizing geospatial coverage and temporal availability while minimizing the number of deployed devices. Additionally, estimated walking time is used to determine a more accurate time-to-retrieve a device rather than traditional straight-line approximations. An interactive tool is developed to allow a decision-makers to change parameters and observe effects on benefits and cost. The approach is deployed and evaluated for a sample urban environment. We simulate an average decrease of time-to-retrieve by 98.06 seconds indicating an estimated 11.44% to 16.3% survival probability improvement using our optimization technique compared to a baseline optimization.
Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability, 2009
Abstract: This paper extends the current stochastic network interdiction problem (SNIP) approache... more Abstract: This paper extends the current stochastic network interdiction problem (SNIP) approaches to allow for the inclusion of multistate behaviour of link flow when a given link is targeted for interdiction. Under this modelling scenario, described as the multistate SNIP, a new ...
Reliability Engineering & System Safety, 2009
This paper presents a network optimization model that maximizes the survivability of a network fo... more This paper presents a network optimization model that maximizes the survivability of a network for a specific sourcesink flow when resources are allocated to protect network links under an evenly distributed attack strategy. The proposed model takes into account the stochastic ...
Reliability Engineering & System Safety, 2004
The redundancy allocation problem is formulated with the objective of minimizing design cost, whe... more The redundancy allocation problem is formulated with the objective of minimizing design cost, when the system exhibits a multi-state reliability behavior, given system-level performance constraints. When the multi-state nature of the system is considered, traditional solution methodologies are no longer valid. This study considers a multi-state series-parallel system (MSPS) with capacitated binary components that can provide different multi-state system performance levels. The different demand levels, which must be supplied during the systemoperating period, result in the multi-state nature of the system. The new solution methodology offers several distinct benefits compared to traditional formulations of the MSPS redundancy allocation problem. For some systems, recognizing that different component versions yield different system performance is critical so that the overall system reliability estimation and associated design models the true system reliability behavior more realistically. The MSPS design problem, solved in this study, has been previously analyzed using genetic algorithms (GAs) and the universal generating function. The specific problem being addressed is one where there are multiple component choices, but once a component selection is made, only the same component type can be used to provide redundancy. This is the first time that the MSPS design problem has been addressed without using GAs. The heuristic offers more efficient and straightforward analyses. Solutions to three different problem types are obtained illustrating the simplicity and ease of application of the heuristic without compromising the intended optimization needs. q
The TQM Magazine, 2007
Purpose -The evolution of six sigma has morphed from a method or set of techniques to a movement ... more Purpose -The evolution of six sigma has morphed from a method or set of techniques to a movement focused on business-process improvement. Business processes are transformed through the successful selection and implementation of competing six sigma projects. However, the efforts to implement a six sigma process improvement initiative alone do not guarantee success. To meet aggressive schedules and tight budget constraints, a successful six sigma project needs to follow the proven define, measure, analyze, improve, and control methodology. Any slip in schedule or cost overrun is likely to offset the potential benefits achieved by implementing six sigma projects. The purpose of this paper is to focus on six sigma projects targeted at improving the overall customer satisfaction called Big Q projects. The aim is to develop a mathematical model to select one or more six sigma projects that result in the maximum benefit to the organization. Design/methodology/approach -This research provides the identification of important inputs and outputs for six sigma projects that are then analyzed using data envelopment analysis (DEA) to identify projects, which result in maximum benefit. Maximum benefit here provides a Pareto optimal solution based on inputs and outputs directly related to the efficiency of the six sigma projects under study. A sensitivity analysis of efficiency measurement is also carried out to study the impact of variation in projects' inputs and outputs on project performance and to identify the critical inputs and outputs. Findings -DEA, often used for relative efficiency analysis and productivity analysis, is now successfully constructed for six sigma project selection. Practical implications -Provides a practical approach to guide the selection of six sigma projects for implementation, especially for companies with limited resources. The sensitivity analysis discussed in the paper helps to understand the uncertainties in project inputs and outputs. Originality/value -This paper introduces DEA as a tool for six sigma project selection.
Reliability Engineering & System Safety, 2007
... rules have been developed by Rocco and Muselli [7]. These researchers have employed classific... more ... rules have been developed by Rocco and Muselli [7]. These researchers have employed classification techniques to produce an estimate of the reliability expression, which provides reasonably accurate values of the reliability and the MMCV. Recently, Ramirez-Marquez and ...
Reliability Engineering & System Safety, 2005
... A Monte-Carlo simulation approach for approximating multi-state two-terminal reliability. ...... more ... A Monte-Carlo simulation approach for approximating multi-state two-terminal reliability. ... Available online 15 July 2004. Abstract. This paper describes a Monte-Carlo (MC) simulation methodology for estimating the reliability of a multi-state network. ...
Reliability Engineering & System Safety, 2008
The mobile ad-hoc wireless network (MAWN) is a new and emerging network scheme that is being empl... more The mobile ad-hoc wireless network (MAWN) is a new and emerging network scheme that is being employed in a variety of applications. The MAWN varies from traditional networks because it is a self-forming and dynamic network. The MAWN is free of infrastructure and, as such, ...
IEEE Transactions on Reliability - TR
This paper describes an extension of a classical network reliability problem to the multi-state c... more This paper describes an extension of a classical network reliability problem to the multi-state case. The two-terminal reliability (2TR) problem assumes a network and its elements can be in either a working or a failed state. However, many practical networks are built of elements that may operate in more than two states. The major focus of this study is to develop a methodology for obtaining the multi-state equivalent of binary cut sets, namely, multi-state minimal cut vectors (MMCV), for the multi-state two-terminal reliability (M2TR) problem. The algorithm uses an information sharing approach that significantly reduces the number of vector enumerations needed to obtain all MMCV. The algorithm mimics natural organisms in that a select number of MMCV, called "offspring cuts," inherit information from other MMCV called "parent cuts." Additionally, the paper discusses the computation of reliability once the MMCV are known. For large systems with even a relatively s...
Systems Engineering, 2009
The purpose of this paper is to describe a methodology that enables systems engineers or program ... more The purpose of this paper is to describe a methodology that enables systems engineers or program managers to formulate a system-wide optimal development plan in order to facilitate monitoring and evaluation of the development process in terms of the actual readiness of the system. It proposes the use of the System Readiness Level (SRL) scale to measure the maturity of a system composed of technological elements, which are being developed based on cost-driven strategies (as opposed to time-to-marketdriven strategies). A constrained optimization model is used to identify which critical technology elements and integration links can be matured to which levels at a particular time such that the development costs are minimized while a targeted SRL value is attained on schedule. While the algorithm does not necessarily reduce the total cost of development, it is able to find the minimal amount of expenditures which will achieve the desired maturity level during the earlier part of the development process. Essentially, it shifts the rest of the expenditures towards the latter part of the development during which model-based integration and testing procedures which have been suggested by others can be applied to reduce costs and time further. This can be a useful option to have when there is substantial uncertainty with the system due to its high novelty and technological content. As a value added approach, the model gives the systems engineer the information needed to understand what a delay may mean to development, so a more informed decision can be made. The paper concludes by discussing the possible use of the optimal development plan to monitor and control the progress of systems under development.
Reliability Engineering & System Safety, 2007
... They developed a solution space reduction procedure and a branch-and-bound algorithm to obtai... more ... They developed a solution space reduction procedure and a branch-and-bound algorithm to obtain a solution ... Note: I i defines the probability that component type i fails due to an independent cause ... This model is a general approximation to the exact common cause failure model ...
Reliability Engineering & System Safety, 2009
This paper introduces an evolutionary optimization approach that can be readily applied to solve ... more This paper introduces an evolutionary optimization approach that can be readily applied to solve deterministic network interdiction problems. The network interdiction problem solved considers the minimization of the maximum flow that can be transmitted between a source node and ...
Reliability Engineering & System Safety, 2009
The reliability of ad-hoc networks is gaining popularity in two areas: as a topic of academic int... more The reliability of ad-hoc networks is gaining popularity in two areas: as a topic of academic interest and as a key performance parameter for defense systems employing this type of network. The ad-hoc network is dynamic and scalable and these descriptions are what attract its users. ...
Reliability Engineering & System Safety, 2006
... José E. Ramírez-Márquez Corresponding Author Contact Information , E-mail The Corresponding A... more ... José E. Ramírez-Márquez Corresponding Author Contact Information , E-mail The Corresponding Author and Wei Jiang [Author vitae]. ... Dotson & Gobien [3] developed an algorithm for determining 2TR based on set theory and matrix algebra. ...
Reliability Engineering & System Safety, 2006
In this paper, new importance measures for multi-state systems with multi-state components are in... more In this paper, new importance measures for multi-state systems with multi-state components are introduced and evaluated. These new measures complement and enhance current work done in the area of multi-state reliability. In general, importance measures are used to evaluate and rank the criticality of component or component states with respect to system reliability. The focus of the study is to provide intuitive and clear importance measures that can be used to enhance system reliability from two perspectives: (1) how a specific component affects multi-state system reliability and (2) how a particular component state or set of states affects multi-state system reliability. The first measure unsatisfied demand index, provides insight regarding a component or component state contribution to unsatisfied demand. The second measure multi-state failure frequency index, elaborates on an approach that quantifies the contribution of a particular component or component state to system failure. Finally, the multi-state redundancy importance identifies where to allocate component redundancy as to improve system reliability. The findings of this study indicate that both perspectives can be used to complement each other and as an effective tool to assess component criticality. Examples illustrate and compare the proposed measures with previous multi-state importance measures. q Reliability Engineering and System Safety 91 (2006) 894-904 www.elsevier.com/locate/ress 0951-8320/$ -see front matter q
Reliability Engineering & System Safety, 2007
Availability is one of the metrics often used in the evaluation of system effectiveness. Its use ... more Availability is one of the metrics often used in the evaluation of system effectiveness. Its use as an effectiveness metric is often dictated by the nature of the system under consideration. While some systems operate continuously, many others operate on an intermittent basis where each operational period may often involve a different set of missions. This is the most likely
Reliability Engineering & System Safety, 2007
Reliability is one of the most important performance measures for emerging technologies. For thes... more Reliability is one of the most important performance measures for emerging technologies. For these systems, shortcomings are often overlooked in early releases as the cutting edge technology overshadows a fragile design. Currently, the proliferation of the mobile ad hoc wireless ...
Reliability Engineering & System Safety, 2008
... José Emmanuel Ramirez-Marquez a , Corresponding Author Contact Information , E-mail The Corre... more ... José Emmanuel Ramirez-Marquez a , Corresponding Author Contact Information , E-mail The Corresponding Author and Claudio M. Rocco b. ... updates the state space region to be searched via a penalty function and a subset with binary information of the best solutions found ...
International Journal of Production Economics, 2008
Six Sigma is at the top of the agenda for many companies that try to reduce cost and improve prod... more Six Sigma is at the top of the agenda for many companies that try to reduce cost and improve productivity. Many of the top manufacturing companies implement thousands of Six Sigma projects every year and this implementation demands a significant investment of capital ...
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Papers by Jose Ramirez-marquez