Modelling interval data with Normal and Skew-Normal distributions

A parametric modelling for interval data is proposed, assuming a multivariate Normal or Skew-Normal distribution for the midpoints and log-ranges of the interval variables. The intrinsic nature of the interval variables leads to special structures of the variance–covariance matrix, which is represented by five different possible configurations. Maximum likelihood estimation for both models under all considered configurations is studied. The proposed modelling is then considered in the context of analysis of variance and multivariate analysis of variance testing. To access the behaviour of the proposed methodology, a simulation study is performed. The results show that, for medium or large sample sizes, tests have good power and their true significance level approaches nominal levels when the constraints assumed for the model are respected; however, for small samples, sizes close to nominal levels cannot be guaranteed. Applications to Chinese meteorological data in three different regions and to credit card usage variables for different card designations, illustrate the proposed methodology.     

Complexity properties of complementary prisms

The complementary prism \(G\bar{G}\) of a graph G arises from the disjoint union of the graph G and its complement \(\bar{G}\) by adding the edges of a perfect matching joining pairs of corresponding vertices of G and \(\bar{G}\). Haynes, Henning, Slater, and van der Merwe introduced the complementary prism and as a variation of the well-known prism. We study algorithmic/complexity properties of complementary prisms with respect to cliques, independent sets, k-domination, and especially \(P_3\)-convexity. We establish hardness results and identify some efficiently solvable cases.     

Measuring Stability and Change: Methodological Issues in Quality of Life studies

The aim of the paper is to show how the variety of approaches to study social change may result in a challenging complexity for the social scientist, starting from the difficulty of defining the concept of “change” itself and managing it through observed data. This is particularly true in presence of complex phenomena, such as those defining and composing the quality of life. What should be pointed out is that quality of life studies not only are focused on the present time but have also long term perspectives. This represents the link between studies on quality of life and forecasting. When applied to the field of quality of life, the typical logical approach to forecasts, based upon inferential statistics, could reveal its limits. Those limits are related to different aspects: e.g., the forms of relationships between different aspects of the phenomenon, which can be linear and non-linear; the dimensionality of phenomenon, which can turn out to be very complex; the causality, which could be direct or indirect; the entity of change, which implies the idea that also small change can have great impact; the perspective of observation, which can be internal or external and local or global. Consequently, the study of change related to quality of life needs, in addition to the traditional statistical tools as well as the tradition of social indicators, a different approach. Although the Futures Studies are not a proper science, nevertheless their approach to social research may ensure the requested accuracy of a scientific forecasting process.     

Use of jump process to model mobility in massive multiplayer on-line games

This paper proposes a methodology to model the mobility of characters in Massively Multiplayer On-line (MMO) Games. We propose to model the mobility of characters in the map of an MMO game as a jump process using two approaches to model the times spent in the states of the process: parametric and non-parametric. Furthermore, a simulator for the mobility is presented. We analyze geographic position data of the characters in the map of the game World of Warcraft and compare the observed and simulated data. The proposed methodology and the simulator can be used to optimize computing load allocation of servers, which is extremely important for game performance, service quality and cost.     

Work–family conflict and job insecurity: are workers from different generations experiencing true differences?

This paper explores the question whether workers of different generations significantly diverge in their perceptions of work–family conflict and job insecurity and implications of such differences on affective commitment and job satisfaction. Given the explorative nature of this study, we use a multi-method approach which relies on a focus group with Italian graduated students and on a field study with workers from an Italian food processing company respectively grouped in three generational cohorts: Baby Boomers, gen Xers, and Millennials. Overall, our findings demonstrate that workers belonging to different generational cohorts display divergent perceptions of work–family conflict and job insecurity. However, the effects of such perceptions on work attitudes are not directly correlated with the experienced levels of job insecurity and work–family conflict. That is, although Millennials tend to perceive a higher level of job insecurity than Baby Boomers and gen Xers, job insecurity is more likely to produce negative consequences on work attitudes among Baby Boomers and gen Xers rather than among Millennials. Notably, our findings indicate that there are no significant differences with regard to the effects of work–family conflict on affective commitment and job satisfaction among the three generational cohorts considered.     

Preaching to the Choir: Are the Commission’s Recommendations Already Applied?

As we have seen, the Commission’s final report outlines a comprehensive framework by defining some guidelines by: (a) identifying the limits of GDP as an indicator of economic performance and social progress, including measurement problems; (b) considering what additional information might be required for the production of more relevant social progress indicators; and (c) assessing the feasibility of alternative measurement and presentation tools. The report argues that GDP should not be completely eliminated by the options for measuring progress, but must be integrated with other information. In particular, the Committee defines three major areas in which indicators should be developed: economic conditions, quality of life and sustainability. In the European scene, but not only, there are many initiatives that aim at measuring the progress of countries and well-being through different conceptual frameworks and by using several indicators. This work intends to analyze some of those relevant initiatives by comparing and confronting them to the Commission’s recommendations, in order to check what already fits the commission recommendations and what still needs to be defined in that perspective.     

Activity at work, innovation and sustainable development

The aim of this paper is to present and discuss a French-Brazilian project (CAPES-COFECUB) centered on the relations between sustainable development, innovation and changes in work activities that accompany these innovations for sustainable development. Sustainable development calls for an integrated approach of three dimensions: social equity, economic viability and environmental sustainability. In order to achieve this integration, considerable innovations efforts are required. However, the work, understood as a productive act, is deeply lacking in the current researches. Starting from the idea that work is a "fundamental need" the goal of this project is to propose innovative methods that can be used for designing production systems from the perspective of sustainable development.     

The start up as a phase of architectural design process

Alterations made in the architectural design can be considered as a continuous process, from its conception to the moment a built environment is already in use. This article focuses on the "moving phase", which is the initial moment of the environment occupation and the start-up of services. It aims to show that the continuity of ergonomics interventions during the "moving phase" or start up may reveal the built environment inadequacies; clearly showing needs not met by the design and allowing making instant decisions to solve non-foreseen problems. The results have revealed some lessons experienced by users during a critical stage not usually included in the design process.     

Measuring organizational effectiveness in information and communication technology companies using item response theory

The aim of this paper is to measure the effectiveness of the organizations Information and Communication Technology (ICT) from the point of view of the manager, using Item Response Theory (IRT). There is a need to verify the effectiveness of these organizations which are normally associated to complex, dynamic, and competitive environments. In academic literature, there is disagreement surrounding the concept of organizational effectiveness and its measurement. A construct was elaborated based on dimensions of effectiveness towards the construction of the items of the questionnaire which submitted to specialists for evaluation. It demonstrated itself to be viable in measuring organizational effectiveness of ICT companies under the point of view of a manager through using Two-Parameter Logistic Model (2PLM) of the IRT. This modeling permits us to evaluate the quality and property of each item placed within a single scale: items and respondents, which is not possible when using other similar tools.     

Organizational factors related to occupational accidents in construction

The purpose of this paper is to understand the influence of organizational factors on occupational accident causation. A field study was undertaken and focused on the phase of concreting the floors of a residential block in a building project in Brazil. The methodological approach was based on the analysis of carpenters' work practices and of the workers' accounts of minor falls. Observations were noted on work practices over this stage. Furthermore, interviews were conducted with the workers hired by the subcontractors and with professionals working for the main contractor. The results show that falls were related to the introduction of new building technology and its use by the workforce. The production planning and organization of activities by the subcontracted firms also led to temporary demands that were additional determining factors for falls on site. The work analysis reveals the need to consider organizational factors in prevention practices.