Luis G Vargas - Academia.edu (original) (raw)

Papers by Luis G Vargas

The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

This paper develops an axiomatization of the Analytic Hierarchy Process for decision-making under... more This paper develops an axiomatization of the Analytic Hierarchy Process for decision-making under uncertainty. We find that with this axiomatization the AHP priority function is proportional to an exponential of a Dyer-Sarin comparative utility function with a fixed reference point.

Proceedings of the International Symposium on the Analytic Hierarchy Process, 1996

We examine some examples where the use of cardinal preferences solves problems that occur when or... more We examine some examples where the use of cardinal preferences solves problems that occur when ordinal preferences are used exclusively. Ordinal preferences are the first step toward ranking alternatives but they are not the last. In general we are interested in deriving a consistent ranking of alternatives which may then be used to construct a scale after a unit of measurement has been developed.

International Series in Operations Research & Management Science, 2001

Each actor has individual objectives. The objectives for the different actors were carefully defi... more Each actor has individual objectives. The objectives for the different actors were carefully defined based on specific research on each of them. The next step was to identify all the policies being currently implemented by the different actors in order to achieve their respective objectives. Also costs and benefits for each of the objectives were identified.

Proceedings of the International Symposium on the Analytic Hierarchy Process, 1999

The seven pillars of the AHP, some highlights of which are discussed in the paper, are: 1) ratio ... more The seven pillars of the AHP, some highlights of which are discussed in the paper, are: 1) ratio scales derived from reciprocal paired comparisons; 2) paired comparisons and the psychophysical origin of the fundamental scale used to make the comparisons; 3) conditions for sensitivity of the eigenvector to changes in judgments; 4) homogeneity and clustering to extend the scale from 1-9 to 1-Go; 5) additive synthesis of priorities, leading to a vector of multi-linear forms as applied within the decision structure of a hierarchy or the more general feedback network to reduce multi-dimensional measurements to a uthdimensional ratio scale; 6) allowing rank preservation (ideal mode) or allowing rank reversal (distributive mode); and 7) group decision making using a mathematically justifiable way for synthesizing individual judgments which allows the construction of a cardinal group decision compatible with the individual preferences.

International Series in Operations Research & Management Science, 2001

íερá áρχή is the Greek word for hierarchy meaning holy origin or holy rule1. It is the ordering o... more íερá áρχή is the Greek word for hierarchy meaning holy origin or holy rule1. It is the ordering of parts or elements of a whole from the highest to the lowest. A hierarchy is the principle of control that secures the effective functioning of the organization2.

A retributive conflict is a conflict in which the parties decide on courses of action not just be... more A retributive conflict is a conflict in which the parties decide on courses of action not just because of the benefits they accrue but also because of the costs they exert on the other party. The AHP has been used to study this conflict and to provide potential solutions that could lead to a peace agreement. We show how the AHP is used to assess the concessions/tradeoffs of the parties and how an agreement in principles has resulted pointing to a possible solution of the conflict.

Proceedings of the International Symposium on the Analytic Hierarchy Process, 2014

This paper addresses the derivation of a Euclidean center and its application to interval recipro... more This paper addresses the derivation of a Euclidean center and its application to interval reciprocal matrices. An Euclidean center is defined as the point in decision space from which one can inscribe the largest sphere contained by the constraints. We extend this concept by introducing its weighted version, which we term the weighted Euclidean center. We show that by assigning weights to the different decision variables we can traverse the entire decision space. In addition, we show that the concept of a weighted Euclidean center and that of the achievement scalarizing function introduced by Wierzbicki are intimately related.

Medical decision making : an international journal of the Society for Medical Decision Making, 2018

Current colorectal cancer screening guidelines by the US Preventive Services Task Force endorse m... more Current colorectal cancer screening guidelines by the US Preventive Services Task Force endorse multiple options for average-risk patients and recommend that screening choices should be guided by individual patient preferences. Implementing these recommendations in practice is challenging because they depend on accurate and efficient elicitation and assessment of preferences from patients who are facing a novel task. To present a methodology for analyzing the sensitivity and stability of a patient's preferences regarding colorectal cancer screening options and to provide a starting point for a personalized discussion between the patient and the health care provider about the selection of the appropriate screening option. This research is a secondary analysis of patient preference data collected as part of a previous study. We propose new measures of preference sensitivity and stability that can be used to determine if additional information provided would result in a change to t...

Mathematical Modelling, 1987

The Analytic Hierarchy Process is used to show how forecasts can be made of the effects of moneta... more The Analytic Hierarchy Process is used to show how forecasts can be made of the effects of monetarist, Keynesian and supply-side macroeconomic policies and to determine their impact on important variables such as unemployment, inflation and GNP growth.

Journal of Management Information Systems, 1999

After several years in private industry, he earned his Ph.D. in 1995 from the Katz Graduate Schoo... more After several years in private industry, he earned his Ph.D. in 1995 from the Katz Graduate School of Business, University of Pittsburgh, specializing in artificial intelligence. His current research interests focus on data mining and computational modeling for decision support. His work has been published in various journals, including Information and Management, Interfaces, Expert Systems with Applications, and IEEE Transactions on Knowledge and Data Engineering.

Springer eBooks, 2013

Multi-criteria decision making (MCDM) was used to make comparative analysis of projects or hetero... more Multi-criteria decision making (MCDM) was used to make comparative analysis of projects or heterogeneous measures for prioritization criteria and subcriteria simultaneously in a complex situation. The aim of this paper is to determine the alternatives and the sensitivity of main factors affecting water and energy consumption as well as environmental impact in a recycled paper manufacturing by using analytic hierarchy process (AHP). The AHP enables one to consider all the elements of decision process in a model, and to compare criteria and subcriteria of the model to find the best alternative. The AHP technique is applied through specific software package with user-friendly interfaces called Expert Choice. The results indicated that reduction of water consumption is the most important alternative for sustainable development in a recycled paper mill in Iran. Also, good housekeeping is the most sensitive criterion affecting the alternatives. The paper illustrates how the AHP method can help industrial management to overcome the energy usage and environmental impact in the manufacture.

This research-in-process is exploring a contingency approach to the construction and selection of... more This research-in-process is exploring a contingency approach to the construction and selection of data mining models for predictive classification. This approach considers the structure of the data set and the relationships between and among the various attributes characterizing the data set, with the goal of selecting a model that provides greater insight into the data – and therefore predicts most accurately -- given a particular data structure. Preliminary results obtained from analysis of hospital patient records indicate that concentration indices, commonly used to measure firm concentration within an industry, are useful in characterizing data set structures and therefore in guiding the model selection process. The eventual goal of this research is the construction of a decision support system that can aid decision makers in the model selection task.

Proceedings / the ... Annual Symposium on Computer Application [sic] in Medical Care. Symposium on Computer Applications in Medical Care, 1994

International Series in Operations Research & Management Science, 2013

The paper presents a solution to a real, current and significant problem for Poland. Poland, as a... more The paper presents a solution to a real, current and significant problem for Poland. Poland, as a new EU country should join the Economic and Monetary Union-the euro zone after fulfilling the convergence criteria set by the Maastricht Treaty, as soon as possible. Entering the zone it should gain in many economic, social and political fields. We can therefore look for new opportunities. However, entering the euro zone is results also in costs and risks. The paper aims to find such an alternative which would maximize benefits and opportunities and minimalize costs and risks. The alternatives were developed-early, medium-term and late entry of Poland's into the euro zone. The problem was solved by use of Analytical Network Process. Using multiplicative and additive/negative mathematical formulae the conclusions show, without any doubt, that Poland should enter the euro zone late, that is after 2011.

Proceedings of the 2010 Winter Simulation Conference, 2010

The advanced scheduling of patients for elective surgeries is challenging when the operating room... more The advanced scheduling of patients for elective surgeries is challenging when the operating room capacity usage by these procedures is uncertain. We study the application of some revenue management concepts and techniques to operating rooms for several surgical procedures performed in a multi-tier reimbursement system. Our approach focuses on booking requests for elective procedures, under the assumption that each request uses a random amount of time. We create and use a modified version of Belobaba's well-known EMSRb algorithm (Belobaba 1989) to decide on near-optimal protection levels for various classes of patients. Under the random resource utilization assumption, we decide, for each planning horizon, how much time to reserve for satisfying the demand coming from each class of patients, based on the type of surgical procedure requested and the patient's reimbursement level.

Socio-Economic Planning Sciences, 1991

Each year graduate business admissions committees must carefully evaluate prospective students. C... more Each year graduate business admissions committees must carefully evaluate prospective students. Committees must judge the performance of applicants with respect to a wide range of quantitative and qualitative criteria in order to select the best students. The overall process is complex and time consuming. In this paper, we construct an easy-to-use, replicable model that can aid such admissions committees in the selection process.

Journal of the American Medical Informatics Association, 1997

The plans for Resource Coordination for Surgical Services system (RCSS) incorporate a distributed... more The plans for Resource Coordination for Surgical Services system (RCSS) incorporate a distributed objectbase with a coordinating server. User-centered information screens are customized for each geographic location in surgical services. User interfaces are designed to mimic paper lists and worksheets used by health care providers. Patient-specific and site-specific data will be entered and maintained by providers at each geographic location, but also rebroadcast and displayed for all providers. Although RCSS is primarily a communications system, it will also support review of surgical utilization and operative scheduling.

Journal of Multi-Criteria Decision Analysis, 2012

In most long-lasting conflicts, each party's grievances increase while the concessions they are w... more In most long-lasting conflicts, each party's grievances increase while the concessions they are willing to make decline in number, quality, and perceived value. Both parties lose sight of what they are willing to settle for, generally exaggerate their own needs, and minimize the needs of the other side over time. But, it is precisely the matter of trading that needs to be made more concrete and of higher priority for both sides, if a meaningful resolution is to be found. Without a formal way of trading off the concessions and packages of concessions, both sides are likely to suspect that they are getting the short end of the bargain. All of this requires going beyond verbal descriptions of the concessions to more broadly include their economic, social, geographic, humanitarian and historical worth. It is critical that all of this needs to be translated into priorities derived in terms of the different values and beliefs of the parties. The Analytic Hierarchy Process (AHP) provides a way to perform such an assessment with the participation of negotiators for the parties. It is a positive approach that makes it possible to reason and express feelings and judgments with numerical intensities to derive priorities. With the assistance of panels of Israeli participants and Palestinian participants brought together in 2009 and 2010, AHP was applied for the first time to the Palestinian-Israeli conflict. AHP makes it possible to evaluate moderate and extreme viewpoints and determine their effect on the trading of concessions.

European Journal of Operational Research, 2011

An innovative Analytic Hierarchy Process-based structure is developed to capture the relationship... more An innovative Analytic Hierarchy Process-based structure is developed to capture the relationship between various levels of activities contributed by people to society. Physical objects have widespread extension and degrees of importance that often differ by many orders of magnitude. Similarly, mental thoughts and criteria occur in widely heterogeneous entities that have to be sorted and arranged into homogeneous groups of few elements in each group so that one can evaluate the relationships among them accurately, from the smallest to the largest. It is through such a framework for organizing factors with smooth transition that it is possible to derive reliable priorities from expert judgments. The proposed model enables one to make decisions and allocate resources in as detailed and fine a way as possible. In addition to the traditional approach of structuring criteria into multiple clusters, the alternatives of a decision are also organized into the lowest multiple levels of that hierarchy. This arrangement and evaluation of alternatives differs from one criterion to another, which adds to the complexity of the undertaking when the alternatives are heterogeneous. The coherent approach to structuring complex decisions with the Analytic Hierarchy Process enables one to transcend the complexity of dealing in a scientific way with the problem of widespread orders of magnitude of criteria and alternatives in a complex decision. When the magnitudes are actually very small or very large, the accuracy of rating alternatives one at a time instead of comparing them in pairs involves much guessing, and can lead to a questionable outcome. Alternatively, comparisons, which are necessary for the measurement of intangibles, have greater and better justified accuracy.

The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

This paper develops an axiomatization of the Analytic Hierarchy Process for decision-making under... more This paper develops an axiomatization of the Analytic Hierarchy Process for decision-making under uncertainty. We find that with this axiomatization the AHP priority function is proportional to an exponential of a Dyer-Sarin comparative utility function with a fixed reference point.

Proceedings of the International Symposium on the Analytic Hierarchy Process, 1996

We examine some examples where the use of cardinal preferences solves problems that occur when or... more We examine some examples where the use of cardinal preferences solves problems that occur when ordinal preferences are used exclusively. Ordinal preferences are the first step toward ranking alternatives but they are not the last. In general we are interested in deriving a consistent ranking of alternatives which may then be used to construct a scale after a unit of measurement has been developed.

International Series in Operations Research & Management Science, 2001

Each actor has individual objectives. The objectives for the different actors were carefully defi... more Each actor has individual objectives. The objectives for the different actors were carefully defined based on specific research on each of them. The next step was to identify all the policies being currently implemented by the different actors in order to achieve their respective objectives. Also costs and benefits for each of the objectives were identified.

Proceedings of the International Symposium on the Analytic Hierarchy Process, 1999

The seven pillars of the AHP, some highlights of which are discussed in the paper, are: 1) ratio ... more The seven pillars of the AHP, some highlights of which are discussed in the paper, are: 1) ratio scales derived from reciprocal paired comparisons; 2) paired comparisons and the psychophysical origin of the fundamental scale used to make the comparisons; 3) conditions for sensitivity of the eigenvector to changes in judgments; 4) homogeneity and clustering to extend the scale from 1-9 to 1-Go; 5) additive synthesis of priorities, leading to a vector of multi-linear forms as applied within the decision structure of a hierarchy or the more general feedback network to reduce multi-dimensional measurements to a uthdimensional ratio scale; 6) allowing rank preservation (ideal mode) or allowing rank reversal (distributive mode); and 7) group decision making using a mathematically justifiable way for synthesizing individual judgments which allows the construction of a cardinal group decision compatible with the individual preferences.

International Series in Operations Research & Management Science, 2001

íερá áρχή is the Greek word for hierarchy meaning holy origin or holy rule1. It is the ordering o... more íερá áρχή is the Greek word for hierarchy meaning holy origin or holy rule1. It is the ordering of parts or elements of a whole from the highest to the lowest. A hierarchy is the principle of control that secures the effective functioning of the organization2.

A retributive conflict is a conflict in which the parties decide on courses of action not just be... more A retributive conflict is a conflict in which the parties decide on courses of action not just because of the benefits they accrue but also because of the costs they exert on the other party. The AHP has been used to study this conflict and to provide potential solutions that could lead to a peace agreement. We show how the AHP is used to assess the concessions/tradeoffs of the parties and how an agreement in principles has resulted pointing to a possible solution of the conflict.

Proceedings of the International Symposium on the Analytic Hierarchy Process, 2014

This paper addresses the derivation of a Euclidean center and its application to interval recipro... more This paper addresses the derivation of a Euclidean center and its application to interval reciprocal matrices. An Euclidean center is defined as the point in decision space from which one can inscribe the largest sphere contained by the constraints. We extend this concept by introducing its weighted version, which we term the weighted Euclidean center. We show that by assigning weights to the different decision variables we can traverse the entire decision space. In addition, we show that the concept of a weighted Euclidean center and that of the achievement scalarizing function introduced by Wierzbicki are intimately related.

Medical decision making : an international journal of the Society for Medical Decision Making, 2018

Current colorectal cancer screening guidelines by the US Preventive Services Task Force endorse m... more Current colorectal cancer screening guidelines by the US Preventive Services Task Force endorse multiple options for average-risk patients and recommend that screening choices should be guided by individual patient preferences. Implementing these recommendations in practice is challenging because they depend on accurate and efficient elicitation and assessment of preferences from patients who are facing a novel task. To present a methodology for analyzing the sensitivity and stability of a patient's preferences regarding colorectal cancer screening options and to provide a starting point for a personalized discussion between the patient and the health care provider about the selection of the appropriate screening option. This research is a secondary analysis of patient preference data collected as part of a previous study. We propose new measures of preference sensitivity and stability that can be used to determine if additional information provided would result in a change to t...

Mathematical Modelling, 1987

The Analytic Hierarchy Process is used to show how forecasts can be made of the effects of moneta... more The Analytic Hierarchy Process is used to show how forecasts can be made of the effects of monetarist, Keynesian and supply-side macroeconomic policies and to determine their impact on important variables such as unemployment, inflation and GNP growth.

Journal of Management Information Systems, 1999

After several years in private industry, he earned his Ph.D. in 1995 from the Katz Graduate Schoo... more After several years in private industry, he earned his Ph.D. in 1995 from the Katz Graduate School of Business, University of Pittsburgh, specializing in artificial intelligence. His current research interests focus on data mining and computational modeling for decision support. His work has been published in various journals, including Information and Management, Interfaces, Expert Systems with Applications, and IEEE Transactions on Knowledge and Data Engineering.

Springer eBooks, 2013

Multi-criteria decision making (MCDM) was used to make comparative analysis of projects or hetero... more Multi-criteria decision making (MCDM) was used to make comparative analysis of projects or heterogeneous measures for prioritization criteria and subcriteria simultaneously in a complex situation. The aim of this paper is to determine the alternatives and the sensitivity of main factors affecting water and energy consumption as well as environmental impact in a recycled paper manufacturing by using analytic hierarchy process (AHP). The AHP enables one to consider all the elements of decision process in a model, and to compare criteria and subcriteria of the model to find the best alternative. The AHP technique is applied through specific software package with user-friendly interfaces called Expert Choice. The results indicated that reduction of water consumption is the most important alternative for sustainable development in a recycled paper mill in Iran. Also, good housekeeping is the most sensitive criterion affecting the alternatives. The paper illustrates how the AHP method can help industrial management to overcome the energy usage and environmental impact in the manufacture.

This research-in-process is exploring a contingency approach to the construction and selection of... more This research-in-process is exploring a contingency approach to the construction and selection of data mining models for predictive classification. This approach considers the structure of the data set and the relationships between and among the various attributes characterizing the data set, with the goal of selecting a model that provides greater insight into the data – and therefore predicts most accurately -- given a particular data structure. Preliminary results obtained from analysis of hospital patient records indicate that concentration indices, commonly used to measure firm concentration within an industry, are useful in characterizing data set structures and therefore in guiding the model selection process. The eventual goal of this research is the construction of a decision support system that can aid decision makers in the model selection task.

Proceedings / the ... Annual Symposium on Computer Application [sic] in Medical Care. Symposium on Computer Applications in Medical Care, 1994

International Series in Operations Research & Management Science, 2013

The paper presents a solution to a real, current and significant problem for Poland. Poland, as a... more The paper presents a solution to a real, current and significant problem for Poland. Poland, as a new EU country should join the Economic and Monetary Union-the euro zone after fulfilling the convergence criteria set by the Maastricht Treaty, as soon as possible. Entering the zone it should gain in many economic, social and political fields. We can therefore look for new opportunities. However, entering the euro zone is results also in costs and risks. The paper aims to find such an alternative which would maximize benefits and opportunities and minimalize costs and risks. The alternatives were developed-early, medium-term and late entry of Poland's into the euro zone. The problem was solved by use of Analytical Network Process. Using multiplicative and additive/negative mathematical formulae the conclusions show, without any doubt, that Poland should enter the euro zone late, that is after 2011.

Proceedings of the 2010 Winter Simulation Conference, 2010

The advanced scheduling of patients for elective surgeries is challenging when the operating room... more The advanced scheduling of patients for elective surgeries is challenging when the operating room capacity usage by these procedures is uncertain. We study the application of some revenue management concepts and techniques to operating rooms for several surgical procedures performed in a multi-tier reimbursement system. Our approach focuses on booking requests for elective procedures, under the assumption that each request uses a random amount of time. We create and use a modified version of Belobaba's well-known EMSRb algorithm (Belobaba 1989) to decide on near-optimal protection levels for various classes of patients. Under the random resource utilization assumption, we decide, for each planning horizon, how much time to reserve for satisfying the demand coming from each class of patients, based on the type of surgical procedure requested and the patient's reimbursement level.

Socio-Economic Planning Sciences, 1991

Each year graduate business admissions committees must carefully evaluate prospective students. C... more Each year graduate business admissions committees must carefully evaluate prospective students. Committees must judge the performance of applicants with respect to a wide range of quantitative and qualitative criteria in order to select the best students. The overall process is complex and time consuming. In this paper, we construct an easy-to-use, replicable model that can aid such admissions committees in the selection process.

Journal of the American Medical Informatics Association, 1997

The plans for Resource Coordination for Surgical Services system (RCSS) incorporate a distributed... more The plans for Resource Coordination for Surgical Services system (RCSS) incorporate a distributed objectbase with a coordinating server. User-centered information screens are customized for each geographic location in surgical services. User interfaces are designed to mimic paper lists and worksheets used by health care providers. Patient-specific and site-specific data will be entered and maintained by providers at each geographic location, but also rebroadcast and displayed for all providers. Although RCSS is primarily a communications system, it will also support review of surgical utilization and operative scheduling.

Journal of Multi-Criteria Decision Analysis, 2012

In most long-lasting conflicts, each party's grievances increase while the concessions they are w... more In most long-lasting conflicts, each party's grievances increase while the concessions they are willing to make decline in number, quality, and perceived value. Both parties lose sight of what they are willing to settle for, generally exaggerate their own needs, and minimize the needs of the other side over time. But, it is precisely the matter of trading that needs to be made more concrete and of higher priority for both sides, if a meaningful resolution is to be found. Without a formal way of trading off the concessions and packages of concessions, both sides are likely to suspect that they are getting the short end of the bargain. All of this requires going beyond verbal descriptions of the concessions to more broadly include their economic, social, geographic, humanitarian and historical worth. It is critical that all of this needs to be translated into priorities derived in terms of the different values and beliefs of the parties. The Analytic Hierarchy Process (AHP) provides a way to perform such an assessment with the participation of negotiators for the parties. It is a positive approach that makes it possible to reason and express feelings and judgments with numerical intensities to derive priorities. With the assistance of panels of Israeli participants and Palestinian participants brought together in 2009 and 2010, AHP was applied for the first time to the Palestinian-Israeli conflict. AHP makes it possible to evaluate moderate and extreme viewpoints and determine their effect on the trading of concessions.

European Journal of Operational Research, 2011

An innovative Analytic Hierarchy Process-based structure is developed to capture the relationship... more An innovative Analytic Hierarchy Process-based structure is developed to capture the relationship between various levels of activities contributed by people to society. Physical objects have widespread extension and degrees of importance that often differ by many orders of magnitude. Similarly, mental thoughts and criteria occur in widely heterogeneous entities that have to be sorted and arranged into homogeneous groups of few elements in each group so that one can evaluate the relationships among them accurately, from the smallest to the largest. It is through such a framework for organizing factors with smooth transition that it is possible to derive reliable priorities from expert judgments. The proposed model enables one to make decisions and allocate resources in as detailed and fine a way as possible. In addition to the traditional approach of structuring criteria into multiple clusters, the alternatives of a decision are also organized into the lowest multiple levels of that hierarchy. This arrangement and evaluation of alternatives differs from one criterion to another, which adds to the complexity of the undertaking when the alternatives are heterogeneous. The coherent approach to structuring complex decisions with the Analytic Hierarchy Process enables one to transcend the complexity of dealing in a scientific way with the problem of widespread orders of magnitude of criteria and alternatives in a complex decision. When the magnitudes are actually very small or very large, the accuracy of rating alternatives one at a time instead of comparing them in pairs involves much guessing, and can lead to a questionable outcome. Alternatively, comparisons, which are necessary for the measurement of intangibles, have greater and better justified accuracy.