Croatian Operational Research Review最新文献

{"title":"Efficiency of municipal service providers in the Republic of Croatia","authors":"Alemka Šegota, Ljerka Cerović, D. Maradin","doi":"10.17535/CRORR.2017.0035","DOIUrl":"https://doi.org/10.17535/CRORR.2017.0035","url":null,"abstract":"Municipal services, such as the collection, removal and disposal of waste, are just some of the necessary activities carried out by public authorities","PeriodicalId":44065,"journal":{"name":"Croatian Operational Research Review","volume":"8 1","pages":"537-562"},"PeriodicalIF":0.7,"publicationDate":"2017-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17535/CRORR.2017.0035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47144243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A linear fractional bilevel programming problem with multichoice parameters","authors":"R. Arora, Kavita Gupta","doi":"10.17535/crorr.2017.0032","DOIUrl":"https://doi.org/10.17535/crorr.2017.0032","url":null,"abstract":"A bilevel programming problem (BLPP) is a hierarchical optimization problem where the constraint region of the upper level is implicitly determined by the lower level optimization problem. In this paper, a bilevel programming problem is considered in which the objective functions are linear fractional and the feasible region is a convex polyhedron. Linear fractional objectives in BLPP are useful in production planning, financial planning, corporate planning and so forth. Here, the cost coefficient of the objective functions are multi-choice parameters. The multi-choice parameters are replaced using interpolating polynomials. Then, fuzzy programming is used to find a compromise solution of the transformed BLPP. An algorithm is developed to find a compromise solution of BLPP. The method is illustrated with the help of an example.","PeriodicalId":44065,"journal":{"name":"Croatian Operational Research Review","volume":"8 1","pages":"499-513"},"PeriodicalIF":0.7,"publicationDate":"2017-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17535/crorr.2017.0032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48316814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Organizations of public benefit: performance evaluation using MCDA approach","authors":"D. Górecka, E. Chojnacka","doi":"10.17535/CRORR.2017.0040","DOIUrl":"https://doi.org/10.17535/CRORR.2017.0040","url":null,"abstract":"In many countries, organizations of public benefit play an important role inthe economy and are established only for charitable purposes. Serving the public interest is often connected with certain benefits, such as additional source of revenue, tax advantages or state grants, but also certain obligations, such as guaranteeing trustworthiness and transparency of operations. Taking the role of charities and voluntary organizations into consideration there is a great need to assess properly such entities whereas tools indicated for corporate finance are not appropriate since these units are established for purposes other than profit-making. Moreover, their range of activities is very different. Hence, new assessment methods are needed in order to evaluate them properly. For this reason the main aim of this paper is to propose and apply multi-criteria decision aiding (MCDA) approach to the problem of assessment of organizations of public benefit. The proposed procedure using EVAMIX method for mixed evaluations (deterministic and stochastic) has been employed in the process of appraising and ranking nine Public Benefit Organizations (PBOs) from one of Polish voivodships operating in the field of ‘Ecology, animals and heritage protection’, and eight charities from two neighboring English metropolitan boroughs, operating in the field of ‘Animals’. Rankings of these entities havebeen obtained so that, e.g., a potential donator would have a better base to make his or her decision regarding financial support.","PeriodicalId":44065,"journal":{"name":"Croatian Operational Research Review","volume":"8 1","pages":"613-629"},"PeriodicalIF":0.7,"publicationDate":"2017-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17535/CRORR.2017.0040","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46531645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An empirical analysis of airport efficiency: the Croatian case","authors":"Danijela Rabar, Robert Zenzerović, Josip Šajrih","doi":"10.17535/CRORR.2017.0030","DOIUrl":"https://doi.org/10.17535/CRORR.2017.0030","url":null,"abstract":"The main objective of this paper is to present an empirical application of the DEA method, by proposing an adequate model for determining the relative efficiencies of seven Croatian airports, and by analysing the obtained scores. To highlight different crucial aspects of airport performance in Croatia, four indicators are used for the period 2009-2014: personnel costs/airport throughput unit (ATU), total expenditures excluding personnel costs/ATU and total assets/ATU as input variables, while the output variable is total revenue/ATU. To overcome certain limitations associated with the relationship between the number of the observed entities and the number of employed variables, and to provide dynamic efficiency results that usually reflect reality better than static ones, window analysis is used as an extension of basic input-oriented DEA models. In general, the findings indicate that, over the observed period, performance rankings change, and, with the exception of the last observed year, the relative performance of Croatian airports is gradually declining. Consequently, the airports of Split, Pula and Zadar were found to be efficient (“best practice” airports) in the four years, and the airports of Zagreb and Osijek in one single year. Based on the efficiency score averaged across the observed period, Split turned out to be most efficient whilst Osijek appeared to be least efficient. Total assets per ATU are identified as the most significant source of inefficiency. Using both constant and variable returns to scale assumptions, this paper is the first to decompose the technical efficiency of Croatian airports into two components – pure technical efficiency, which reflects the ability of an airport to obtain maximal outputs at an optimal scale, and scale efficiency, which reflects the distance of an observed airport from the most productive scale size. The significance of these results is in the fact that they offer the possibility of directly identifying inefficiency causes, and can serve as a basis for an a posteriori correction of previously made disadvantageous decisions.","PeriodicalId":44065,"journal":{"name":"Croatian Operational Research Review","volume":"8 1","pages":"471-487"},"PeriodicalIF":0.7,"publicationDate":"2017-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17535/CRORR.2017.0030","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44146250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Hostile model for network reliability analysis","authors":"Dan Lena, F. Robledo, P. Romero","doi":"10.17535/CRORR.2017.0031","DOIUrl":"https://doi.org/10.17535/CRORR.2017.0031","url":null,"abstract":"In reliability analysis, the goal is to determine the probability of consistentoperation of a system. We introduce the Hostile model, where the system under study is a network, and all the components may fail (both sites and links), except for a distinguished subset of sites, called terminals. The Hostile model includes the Classical Reliability model as a particular case. As a corollary, the exact reliability evaluation of a network in the Hostile model belongs to the list of NP-hard computational problems. Traditional methods for the classical reliability model such as Crude Monte Carlo, Importance Sampling and Recursive Variance Reduction are here adapted for the Hostile model. The performance of these methods is finally discussed using real-life networks.","PeriodicalId":44065,"journal":{"name":"Croatian Operational Research Review","volume":"8 1","pages":"489-498"},"PeriodicalIF":0.7,"publicationDate":"2017-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17535/CRORR.2017.0031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42426576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two models of the capacitated vehicle routing problem","authors":"Zuzana Borčinová, Slovakia Žilina","doi":"10.17535/CRORR.2017.0029","DOIUrl":"https://doi.org/10.17535/CRORR.2017.0029","url":null,"abstract":"The aim of the Capacitated Vehicle Routing Problem (CVRP) is to find a set of minimum total cost routes for a fleet of capacitated vehicles based at a single depot, to serve a set of customers. There exist various integer linear programming models of the CVRP. One of the main dierences lies in the way to eliminate sub-tours, i.e. cycles that do not go through the depot. In this paper, we describe a well-known ow formulation of CVRP, where sub-tour elimination constraints have a cardinality exponentially growing with the number of customers. Then we present a mixed linear programming formulation with polynomial cardinality of sub-tour elimination constraints. Both of the models were implemented and compared on several benchmarks.","PeriodicalId":44065,"journal":{"name":"Croatian Operational Research Review","volume":"8 1","pages":"463-469"},"PeriodicalIF":0.7,"publicationDate":"2017-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17535/CRORR.2017.0029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46716629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The art of company financial modelling","authors":"Zoran Lukić","doi":"10.17535/CRORR.2017.0026","DOIUrl":"https://doi.org/10.17535/CRORR.2017.0026","url":null,"abstract":"In corporate finance, the term financial modelling denotes a widely used technique of comprehensive customised quantification of a company’s entire operations. Even though not mathematically strict, such models exhibit descriptive, explanatory and predictive qualities. The paper elaborates on the main steps and principles for building financial models of companies. It also identifies required assumptions and certain statistical properties of well-constructed models. Furthermore, it describes the use of such models for decision support purposes, supplemented by an illustrative example. Finally, it discusses general characteristics and concerns associated with appropriate model construction and use.","PeriodicalId":44065,"journal":{"name":"Croatian Operational Research Review","volume":"8 1","pages":"409-427"},"PeriodicalIF":0.7,"publicationDate":"2017-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17535/CRORR.2017.0026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47418864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation of minimum sample size for identification of the most important features: a case study providing a qualitative B2B sales data set","authors":"M. Bohanec, Dunajska cesta Sl Ljubljana Slovenia Salvirt Ltd., M. K. Borstnar, M. Robnik-Sikonja","doi":"10.17535/CRORR.2017.0033","DOIUrl":"https://doi.org/10.17535/CRORR.2017.0033","url":null,"abstract":"An important task in machine learning is to reduce data set dimensionality, which in turn contributes to reducing computational load and data collection costs, while improving human understanding and interpretation of models. We introduce an operational guideline for determining the minimum number of instances sucient to identify correct ranks of features with the highest impact. We conduct tests based on qualitative B2B sales forecasting data. The results show that a relatively small instance subset is sucient for identifying the most important features when rank is not important.","PeriodicalId":44065,"journal":{"name":"Croatian Operational Research Review","volume":"42 3","pages":"515-524"},"PeriodicalIF":0.7,"publicationDate":"2017-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17535/CRORR.2017.0033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41305553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data anonymization patent landscape","authors":"M. P. Bach, Jasmina Pivar, Ksenija Dumicic","doi":"10.17535/CRORR.2017.0017","DOIUrl":"https://doi.org/10.17535/CRORR.2017.0017","url":null,"abstract":"The omnipresent, unstoppable increase in digital data has led to a greater understanding of the importance of data privacy. Different approaches are used to implement data privacy. The goal of this paper is to develop a data anonymization patent landscape, by determining the following: (i) the trend in data anonymization patenting, (ii) the type of technical content protected in data anonymization, (iii) the organizations and countries most active in patenting data anonymization know-how; and (iv) the topics emerging most often in patent titles. Patents from the PatSeer database relating to data anonymization from 2001 to 2015 were analyzed. We used the longitudinal approach in combination with text mining techniques to develop a data anonymization patent landscape. The results indicated the following. The number of single patent families is growing with a high increase after 2010, thus indicating a positive trend in the area of patenting data anonymization solutions. The majority of patenting activities relate to the G Physics section. Organizations from the USA and Japan assigned the majority of patents related to data anonymization. The results of text mining indicate that the most often used word in titles of data anonymization patents are “anonym*, “method”, “data” and “system”. Several additional words that indicated the most frequent topics related to data anonymization were: “equipment”, “software”, “protection”, “identification”, or “encryption”, and specific topics such as “community”, “medical”, or “service”.","PeriodicalId":44065,"journal":{"name":"Croatian Operational Research Review","volume":"8 1","pages":"265-281"},"PeriodicalIF":0.7,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17535/CRORR.2017.0017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42951832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A decision rule based on goal programming and one-stage models for uncertain multi-criteria mixed decision making and games against nature","authors":"Helena Gaspars-Wieloch","doi":"10.17535/CRORR.2017.0004","DOIUrl":"https://doi.org/10.17535/CRORR.2017.0004","url":null,"abstract":"This paper is concerned with games against nature and multi-criteria decision making under uncertainty along with scenario planning. We focus on decision problems where a deterministic evaluation of criteria is not possible. The procedure we propose is based on weighted goal programming and may be applied when seeking a mixed strategy. A mixed strategy allows the decision maker to select and perform a weighted combination of several accessible alternatives. The new method takes into consideration the decision maker’s preference structure (importance of particular goals) and nature (pessimistic, moderate or optimistic attitude towards a given problem). It is designed for one-shot decisions made under uncertainty with unknown probabilities (frequencies), i.e for decision making under complete uncertainty or decision making under strategic uncertainty. The procedure refers to one-stage models, i.e. models considering combinations of scenarios and criteria (scenario-criterion pairs) as distinct meta-attributes, which means that the novel approach can be used in the case of totally independent payoff matrices for particular targets. The algorithm does not require any information about frequencies, which is especially desirable for new decision problems. It can be successfully applied by passive decision makers, as only criteria weights and the coefficient of optimism have to be declared.","PeriodicalId":44065,"journal":{"name":"Croatian Operational Research Review","volume":"8 1","pages":"61-76"},"PeriodicalIF":0.7,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17535/CRORR.2017.0004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47238434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}