Exploiting Data Mining Techniques for Broadcasting Data in Mobile Computing Environments

Cataloged from PDF version of article.Mobile computers can be equipped with wireless communication devices that enable users to access data services from any location. In wireless communication, the server-to-client (downlink) communication bandwidth is much higher than the client-to-server (uplink) communication bandwidth. This asymmetry makes the dissemination of data to client machines a desirable approach. However, dissemination of data by broadcasting may induce high access latency in case the number of broadcast data items is large. In this paper, we propose two methods aiming to reduce client access latency of broadcast data. Our methods are based on analyzing the broadcast history (i.e., the chronological sequence of items that have been requested by clients) using data mining techniques. With the first method, the data items in the broadcast disk are organized in such a way that the items requested subsequently are placed close to each other. The second method focuses on improving the cache hit ratio to be able to decrease the access latency. It enables clients to prefetch the data from the broadcast disk based on the rules extracted from previous data request patterns. The proposed methods are implemented on a Web log to estimate their effectiveness. It is shown through performance experiments that the proposed rule-based methods are effective in improving the system performance in terms of the average latency as well as the cache hit ratio of mobile clients

Contributions towards smart cities : exploring block level census data for the characterization of change in Lisbon

Dissertation presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Information Systems and Technologies ManagementThe interest in using information to improve the quality of living in large urban areas and its governance efficiency has been around for decades. Nevertheless, the improvements in Information and Communications Technology has sparked a new dynamic in academic research, usually under the umbrella term of Smart Cities. This concept of Smart City can probably be translated, in a simplified version, into cities that are lived, managed and developed in an information-saturated environment. While it makes perfect sense and we can easily foresee the benefits of such a concept, presently there are still several significant challenges that need to be tackled before we can materialize this vision. In this work we aim at providing a small contribution in this direction, which maximizes the relevancy of the available information resources. One of the most detailed and geographically relevant information resource available, for the study of cities, is the census, more specifically the data available at block level (Subsecção Estatística). In this work, we use Self-Organizing Maps (SOM) and the variant Geo-SOM to explore the block level data from the Portuguese census of Lisbon city, for the years of 2001 and 2011. We focus on gauging change, proposing ways that allow the comparison of the two time periods, which have two different underlying geographical bases. We proceed with the analysis of the data using different SOM variants, aiming at producing a two-fold portrait: one, of the evolution of Lisbon during the first decade of the XXI century, another, of how the census dataset and SOM’s can be used to produce an informational framework for the study of cities

Last mile logistics in mega-cities for perishable fruits

Purpose: A common problem in mega cities is congestion, due to the size of the automotive park, this makes that the perishable foods decreasing their organoleptic characteristics or increases their losses, which requires considering the effect of time on routing problems. The state of the art demonstrates the need to formulate new routing models that include the specific characteristics of perishable foods in order to reduce their losses. Design/methodology/approach: A mathematical model was formulated based on two classical models: the three-index vehicle flow model proposed by (Golden, Assad, Levy & Gheysens, 1984) and the time window model proposed by (Cordeau, Desaulniers, Desrosiers, Solomon & Soumis, 1999). We proposed a novel VRP Model that permits reductions loss due to the perishable. Findings: The optimum cost is found with AMP® for twenty nodes, six vehicles and six fruits. For more nodes, a two-phase strategy is proposed, first a clustering based on a modified p-median model and then a VRP for each cluster. Research limitations/implications: The results showed the need to investigate multi-objective models, since the performance measures can be efficiency, quality and response capacity; the model can be applied in other supply chains of perishable foods. Social implications: According to FAO in Logistics practices in the last mile generate between 10-30% of the perishable food loss in developing countries’ mega-cities. Originality/value: A last-mile logistics strategy is proposed to manage delivery routes for fresh fruits in mega-cities, considering the effect of congestion through travel time in the perishability function. The new model it uses the flow variable to control the amount of each fruit arriving to each node and the time variable to define fruit waste or loss depending on the time and type of fruit.Peer Reviewe

A taxonomy of multi-industry labour force skills

This paper proposes an empirical study of the skill repertoires of 290 sectors in the United States over the period 2002–2011. We use information on employment structures and job content of occupations to flesh out structural characteristics of industry-specific know-how. The exercise of mapping the skills structures embedded in the workforce yields a taxonomy that discloses novel nuances on the organization of industry. In so doing we also take an initial step towards the integration of labour and employment in the area of innovation studies

3D Printing for Solving Part Obscolescence

The purpose of this research was to highlight the issue of parts obsolescence and to highlight the possibility of using alternative methods to overcome parts shortage. Specifically, this thesis sought to answer the research question: is the three-dimensional printing technology (3D) an applicable approach to overcome part obsolescence. The research question was answered through data research and survey analysis. Notwithstanding, the diminished manufacturing sources and material shortages (DMSMS) management and other existing approaches, such as forecasting, contracting, and reverse engineering (RE), were discussed briefly in the literature review and profoundly in chapter IV to differentiate among applicable existing solutions toward solving parts obsolescence. This research qualitatively conducted a survey to identify the depth of the applicability of the 3D printing technology approach to be a solution for material shortages in comparison with other approaches to solving this matter

Reusability based on Life Cycle Sustainability Assessment: Case Study on WEEE

AbstractReuse is one of the key strategies of Waste Electrical and Electronic Equipment (WEEE) recycling system in China. Reuse can help realize eco-efficient and sustainable WEEE management, with environmentally friendly materials recovery. At present, reusability of products and components is determined only by the products functional situation or the economic cost benefit analysis. It does not cover all the three pillars of sustainability, including environment, economy and society. In this study, the emerging integrated method, Life Cycle Sustainability Assessment (LCSA), is employed to measure reusability of typical electrical and electronic products and components. The results of case studies show that, LCSA based reusability of typical electrical and electronic products and components will help improve WEEE management policy