Visualizing proportions and dissimilarities by space-filling maps: a large neighborhood search approach

In this paper we address the problem of visualizing a set of individuals, which have attached a statistical value given as a proportion, and a dissimilarity measure. Each individual is represented as a region within the unit square, in such a way that the area of the regions represent the proportions and the distances between them represent the dissimilarities. To enhance the interpretability of the representation, the regions are required to satisfy two properties. First, they must form a partition of the unit square, namely, the portions in which it is divided must cover its area without overlapping. Second, the portions must be made of a connected union of rectangles which verify the so-called box-connectivity constraints, yielding a visualization map called Space-filling Box-connected Map (SBM). The construction of an SBM is formally stated as a mathematical optimization problem, which is solved heuristically by using the Large Neighborhood Search technique. The methodology proposed in this paper is applied to three real-world datasets: the first one concerning financial markets in Europe and Asia, the second one about the letters in the English alphabet, and finally the provinces of The Netherlands as a geographical application.Ministerio de Economía y CompetitividadJunta de AndalucíaEuropean Regional Development Fun

Sistema de control interno y gestión de contrataciones públicas de una unidad ejecutora de un organismo público autónomo, Cusco, 2021

Mediante la presente investigación se quiere determinar el grado de relación que existe entre el Sistema de Control Interno y la Gestión de las Contrataciones Públicas, en un organismo público autónomo, en el departamento del Cusco, en el año 2021, el enfoque utilizado fue el cuantitativo, de tipo básica, el diseño fue el no experimental y transversal y el alcance fue el correlacional. De las dos variables identificadas se aplicó el instrumento de recolección de datos a todos los trabajadores administrativos que tienen relación con las dos variables, se aplicaron dos cuestionarios el primero de 27 ítems y el segundo de 30 ítems, estas cumplen con el criterio de validación de expertos, obtenidos los resultados se han procesados estos mediante el software estadísticos SPSS V. 29, por ende se ha verificado que el coeficiente de correlación arroja un valor de 0.511, concluyendo que la correlación es significativa entre las dos variables, entendiendo que a un mayor grado de control interno las contrataciones públicas cobran mayor importancia, en la entidad adscrita al Ministerio Publico

Design and control of public-service contracts and an application to public transportation systems

Until the end of the 20th century it was common that cities organized, financed, and managed their own public transportation systems. More recently (in Italy mainly during the last decade), many countries liberalized the service provision of public transportation. Although offering local public transportation is a political and financial duty of governments, the service provision is outsourced to a private operator, while the government retains a control position, given to a regulatory agency. This is a common scheme not only in transportation. In close collaboration with the public transportation agency of the city of Bologna, Italy, we designed a methodology to optimize some aspects of the contractual relationship between that agency and the bus operator. We focus on the fines specified by the contract when the operator fails to comply with the service level it has agreed to provide, and on a procedure to measure that service level. Our approach has the advantage that it aligns the incentives of both parties to the benefit of bus riders. We model the agency–operator relationship as a multistage game and find its equilibrium to establish the best operating regime. The game-theoretical approach provides expressions for the fines that the operator should be charged if it does not satisfy the contracted services, and for the optimal agency’s budget to devote to control activities. Second, to check the compliance of the operator with the schedule specified by the contract in a resource-efficient way, we compute how to position the agency’s employees to verify if buses are running according to the specifications of the contract. This is achieved by counting bus services and by checking other quality indicators. We formulate this NP-hard problem as a mixed integer linear program and propose an algorithm to solve it that is effective in providing itineraries for the controllers working for the agency. This paper was accepted by Dimitris Bertsimas, optimization

Design and control of public-service contracts and an application to public transportation systems

Until the end of the 20th century it was common that cities organized, financed, and managed their own public transportation systems. More recently (in Italy mainly during the last decade), many countries liberalized the service provision of public transportation. Although offering local public transportation is a political and financial duty of governments, the service provision is outsourced to a private operator, while the government retains a control position, given to a regulatory agency. This is a common scheme not only in transportation. In close collaboration with the public transportation agency of the city of Bologna, Italy, we designed a methodology to optimize some aspects of the contractual relationship between that agency and the bus operator. We focus on the fines specified by the contract when the operator fails to comply with the service level it has agreed to provide, and on a procedure to measure that service level. Our approach has the advantage that it aligns the incentives of both parties to the benefit of bus riders. We model the agency-operator relationship as a multistage game and find its equilibrium to establish the best operating regime. The gametheoretical approach provides expressions for the fines that the operator should be charged if it does not satisfy the contracted services, and for the optimal agency's budget to devote to control activities. Second, to check the compliance of the operator with the schedule specified by the contract in a resource-efficient way, we compute how to position the agency's employees to verify if buses are running according to the specifications of the contract. This is achieved by counting bus services and by checking other quality indicators. We formulate this NP-hard problem as a mixed integer linear program and propose an algorithm to solve it that is effective in providing itineraries for the controllers working for the agency

Risk-Based Game Modelling for Port State Control Inspections

This thesis aims to develop a new way for port authorities to predict, analyse and make decisions in Port State Control (PSC) inspections. Under the New Inspection Regime (NIR), it is necessary to not only figure out the influence of new regime to the PSC system, but also provide some technical tools capable of predicting the inspection results and supporting the decision-making of port authorities when regulating the inspection policy. The study consists of analysis from multiple perspectives, both qualitative and quantitative. The risk factors influencing the inspection results and the decision-making of port authorities under NIR are identified through the practical inspection records and related literature. The Paris Memorandum of Understanding (MoU) offers the historical inspection records within the region of Europe and the North Atlantic basin, reflecting different conditions in different periods. Given the different inspection system since 2011, port authorities require a brand new perception of the new inspection regime to estimate the inspection results, and further make decisions when making their own inspection policy. To achieve the objective, an incorporation of two types of models that have proved popular and superior is applied in this study. One is the risk assessment model of Bayesian network (BN), the other is the decision-making model of game theory. The BN models in this research utilize a data-driven approach called Tree Augmented Naïve (TAN) learning to derive the structure of the models. Based on the inspection reports collected from Paris MoU, two BNs that represent the situations of Paris MoU inspection system in different periods are constructed. Company performance, the new indicator, is viewed as one of the important factors influencing the inspection results for the first time and considered in the models. The BN model after the implementation of NIR can serve as the prediction tool for estimating inspection results under dynamic situations. Additionally, a comparative analysis between two models is conducted to clarify the influence on PSC inspection system brought by NIR. When constructing the non-cooperative strategic game model between port authorities and ship owners under NIR, the BN model outcomes play a crucial role in this process, highlighting the novelty of this model. Through the analysis and calculation on the payoff matrix, a Nash equilibrium solution representing the theoretical optimal inspection rate for port authorities is obtained. To validate the feasibility and practical significance of the game model, an empirical study is conducted. The statistics are quantitative and collected from different sources, i.e. Basic vessel information from the World Shipping Encyclopaedia (WSE), casualty information from IMO and Lloyd's Register of Shipping, PSC Inspection records from Paris MoU online inspection database, and the estimated value of different cost types from Drewry Shipping Consultants Ltd. The empirical study illustrates the insights of the optimal inspection policy for port authorities (i.e. with the increase of punishment severity, the optimal inspection rates experience a decreasing trend whatever the vessel condition), as well as providing suggestions for them when formulating the optimal inspection policy under various situations. Based on the BN model and the strategic game model after the implementation of NIR, the thesis eventually proposes a decision-making framework for port authorities to prioritise and select the strategies under different situations. The six-step framework incorporates a risk assessment approach and decision-making approach to provide a novel way to rank the candidate options of port authorities in terms of their resources, which enables decision-makers to find optimal strategies to improve the performance of the PSC inspection system under dynamic business environments. In general, this thesis provides important insights for port authorities to ensure that optimal inspection actions are taken to improve safety at sea in a cost effective manner. The two technical tools (i.e. the dynamic prediction tool for inspection results & the optimal inspection strategy), and the decision-making framework proposed in this project are helpful for port authorities within the Paris MoU region when regulating their inspection policy under NIR. Meanwhile, the comparative analysis in this study further clarifies the influence of NIR on new inspection system from different angles for the first time, demonstrating the introduction and implementation of NIR is a wise and positive decision