Towards a Dichotomy for the Possible Winner Problem in Elections Based on Scoring Rules

To make a joint decision, agents (or voters) are often required to provide their preferences as linear orders. To determine a winner, the given linear orders can be aggregated according to a voting protocol. However, in realistic settings, the voters may often only provide partial orders. This directly leads to the Possible Winner problem that asks, given a set of partial votes, whether a distinguished candidate can still become a winner. In this work, we consider the computational complexity of Possible Winner for the broad class of voting protocols defined by scoring rules. A scoring rule provides a score value for every position which a candidate can have in a linear order. Prominent examples include plurality, k-approval, and Borda. Generalizing previous NP-hardness results for some special cases, we settle the computational complexity for all but one scoring rule. More precisely, for an unbounded number of candidates and unweighted voters, we show that Possible Winner is NP-complete for all pure scoring rules except plurality, veto, and the scoring rule defined by the scoring vector (2,1,...,1,0), while it is solvable in polynomial time for plurality and veto.Comment: minor changes and updates; accepted for publication in JCSS, online version available

Design recommendations of floor vibrations induced by human activities

Structural engineers are now facing with new demands towards long spans, lightweight floors in steelconcrete composite construction and big open interiors. Thеsе new design trends аrе leading to the extensive problems related to the serviceability limit state, especially problems with unwanted floor vibrations. Annoying vibrations caused by human activities are an important serviceability problem, which can significantly affect the comfort of people, quality of life and structures functionality. Over past years many design recommendations of floor vibrations induced by human activities have been published. This paper presents a short overview of dynamic loads modeling and design recommendations of floor vibrations induced by human activities

Towards a framework to combine multiobjective optimization and econometrics and an application in economics of education

Acknowledgements. This work was supported by the Spanish Ministry of Science and Innovation (project PID2020-115429GB-I00), by the Andalusian Regional Ministry of Economy, Knowledge, Business and University (PAI group SEJ-532 and project UMA18-FEDERJA-024, also supported by FEDER funding), and by the University of Malaga (project B1-2020 18). Sandra Gonzalez-Gallardo is recipient of a research contract within “Ayudas para la Recualificación del Sistema Universitario Español, Modalidad Margarita Salas”, financiado por la Unión Europea – NextGenerationEU.In this paper, we propose a theoretical framework that combines econometric and multiobjective programming methodologies to help researchers to identify and achieve optimal solutions to socio-economic and management problems. Sometimes, it is important to analyse which combination of values of the explanatory variables -in an econometric model- would imply the simultaneous achievement of the best values of the response variables. In such situations, if certain degree of conflict is observed among the response variables, we propose to formulate a multiobjective optimization problem based on the conclusions obtained from a regression analysis. Subsequently, the application of multiobjective optimization techniques allows gaining a better insight about the conflicting relation between the response variables, and how a balanced “optimal” situation among them could be achieved. This piece of information can be hardly extracted just by econometric techniques. An application in the field of economics of education, related to the analysis of the students’ well-being as a way to improve their academic performance, demonstrates the potential of our proposal.Spanish Ministry of Science and Innovation (project PID2020-115429GB-I00)Andalusian Regional Ministry of Economy, Knowledge, Business and University (PAI group SEJ-532 and project UMA18-FEDERJA-024, also supported by FEDER funding)University of Malaga (project B1-2020 18)“Ayudas para la Recualificación del Sistema Universitario Español, Modalidad Margarita Salas”, financiado por la Unión Europea – NextGenerationE

Data Minimisation in Communication Protocols: A Formal Analysis Framework and Application to Identity Management

With the growing amount of personal information exchanged over the Internet, privacy is becoming more and more a concern for users. One of the key principles in protecting privacy is data minimisation. This principle requires that only the minimum amount of information necessary to accomplish a certain goal is collected and processed. "Privacy-enhancing" communication protocols have been proposed to guarantee data minimisation in a wide range of applications. However, currently there is no satisfactory way to assess and compare the privacy they offer in a precise way: existing analyses are either too informal and high-level, or specific for one particular system. In this work, we propose a general formal framework to analyse and compare communication protocols with respect to privacy by data minimisation. Privacy requirements are formalised independent of a particular protocol in terms of the knowledge of (coalitions of) actors in a three-layer model of personal information. These requirements are then verified automatically for particular protocols by computing this knowledge from a description of their communication. We validate our framework in an identity management (IdM) case study. As IdM systems are used more and more to satisfy the increasing need for reliable on-line identification and authentication, privacy is becoming an increasingly critical issue. We use our framework to analyse and compare four identity management systems. Finally, we discuss the completeness and (re)usability of the proposed framework

Basics of M-Theory

This is a review article of eleven dimensional supergravity in which we present all necessary calculations, namely the Noether procedure, the equations of motion (without neglecting the fermions), the Killing spinor equation, as well as some simple and less simple supersymmetric solutions to this theory. All calculations are printed in much detail and with explicit comments as to how they were done. Also contained is a simple approach to Clifford algebras to prepare the grounds for the harder calculations in spin space and Fierz identities.Comment: 96 pages, corrected and extended versio

Transformational Leadership and Digital Creativity: The Mediating Roles of Creative Self-Efficacy and Ambidextrous Learning

Drawing insights from social cognitive theory and organizational learning theory, this study aims to uncover themediating mechanisms between direct manager’s transformational leadership behaviors and employees’ digital creativity in the context of digital technology. We conducted a field survey in China and collected data from 234 employees who utilized digital technologies to support daily work. Structural equation modelling analysis results showed that employees’ creative self-efficacy and two learning activities (exploitation vs. exploration) effectively transmitted the influence of transformational leadership ondigital creativity. Our study not only contributes to the understanding on effective use of digital technologies, but also provides practical insights for managers in the big data era

Quantitative Ultrasonic Evaluation of Mechanical Properties of Engineering Materials

Progress in the application of ultrasonic techniques to nondestructive measurement of mechanical strength of engineering materials is reviewed. A dormant concept in nondestructive evaluation (NDE) is invoked. The availability of ultrasonic methods that can be applied to actual parts to assess their potential susceptibility to failure under design conditions is discussed. It was shown that ultrasonic methods yield measurements of elastic moduli, microstructure, hardness, fracture toughness, tensile strength, yield strength, and shear strength for a wide range of materials (including many types of metals, ceramics, and fiber composites). It was also indicated that although most of these methods were shown feasible in laboratory studies, more work is needed before they can be used on actual parts in processing, assembly, inspection, and maintenance lines

Post-breeding migration routes of marine turtles from Bonaire and Klein Bonaire, Caribbean Netherlands

The management of small rookeries is key to conserving the regional genetic diversity of marine turtle populations and requires knowledge on population connectivity between breeding and foraging areas. To elucidate the geographic scope of the populations of marine turtles breeding at Bonaire and Klein Bonaire (Caribbean Netherlands) we examined the post-breeding migratory behavior of 5 female loggerheads Caretta caretta, 4 female green turtles Chelonia mydas, and 2 male and 13 female hawksbill turtles Eretmochelys imbricata during the years 2004-2013. After leaving Bonaire, the 24 tracked turtles frequented foraging grounds in 10 countries. The distances swum from Bonaire to the foraging areas ranged from 608 to 1766 km for loggerhead turtles, 198 to 3135 km for green turtles, and 197 to 3135 km for hawksbill turtles, together crossing the waters of 19 countries. Males represented the minority in this study, but we made 2 key observations that require further research: males remained in the vicinity of the breeding area for 3-5 mo, which is 2-5 times longer than females, and males migrated greater distances than previously recorded. Although the turtles dispersed widely across the Caribbean, there appeared to be 2 benthic foraging areas of particular importance to all 3 species of marine turtles breeding at Bonaire, namely the shallow banks east of Nicaragua and Honduras (n = 8 tracked turtles) and Los Roques, Venezuela (n = 3). Marine turtles breeding at Bonaire face threats from legal turtle harvesting, illegal take, and bycatch in the waters that they traverse across the Caribbea