Evidential Clustering: A Review

International audienceIn evidential clustering, uncertainty about the assignment of objects to clusters is represented by Dempster-Shafer mass functions. The resulting clustering structure, called a credal partition, is shown to be more general than hard, fuzzy, possibilistic and rough partitions, which are recovered as special cases. Three algorithms to generate a credal partition are reviewed. Each of these algorithms is shown to implement a decision-directed clustering strategy. Their relative merits are discussed

Interoperability and market foreclosure in the European Microsoft case.

In this paper we discuss some of the most important economic issues raised in European Commission vs. Microsoft (2004) concerning the market for work group servers. In our view, the most important economic issues relate to (a) foreclosure incentives and (b) innovation effects of the proposed remedy. We discuss the economic basis for the Commission’s claims that Microsoft had incentives to exclude rivals in the work group server market through degrading the interoperability of their server operating systems with Windows. We also examine the impact of compulsory disclosure of information on interoperability and argue that the effects on innovation are not unambiguously negative as Microsoft claim. We conclude with some general implications of the case for anti-trust enforcement in high innovation sectors.

Making decisions with evidential probability and objective Bayesian calibration inductive logics

Calibration inductive logics are based on accepting estimates of relative frequencies, which are used to generate imprecise probabilities. In turn, these imprecise probabilities are intended to guide beliefs and decisions — a process called “calibration”. Two prominent examples are Henry E. Kyburg's system of Evidential Probability and Jon Williamson's version of Objective Bayesianism. There are many unexplored questions about these logics. How well do they perform in the short-run? Under what circumstances do they do better or worse? What is their performance relative to traditional Bayesianism? In this article, we develop an agent-based model of a classic binomial decision problem, including players based on variations of Evidential Probability and Objective Bayesianism. We compare the performances of these players, including against a benchmark player who uses standard Bayesian inductive logic. We find that the calibrated players can match the performance of the Bayesian player, but only with particular acceptance thresholds and decision rules. Among other points, our discussion raises some challenges for characterising “cautious” reasoning using imprecise probabilities. Thus, we demonstrate a new way of systematically comparing imprecise probability systems, and we conclude that calibration inductive logics are surprisingly promising for making decisions

Assessment of Information Technology Adoption in Project Information Exchange in Nigerian Construction Industry

Information Technology (IT) has been applied by various industries with significant improvement in the practice and strategic standing of the industries. Its successful application is evident in manufacturing, petroleum, banking, aerospace and military industries. However, despite this evidential benefit as a result of IT adoption, delayed receipt of project information and/or loss of the project data/information are still prevalent in the Nigerian construction industry. To reduce these inefficiencies in the data management of the industry, this study investigates the medium of project information exchange and examine the order of IT adoption in the Nigerian Construction industry. A quantitative approach using questionnaire survey was employed. Structured questionnaires were distributed among quantity surveyors in contracting, consulting and public sector. The resultant data was analyzed using descriptive statistical tool. The results revealed the dominance of the paper-based medium over the use of IT tools in information acquisition and dissemination in the construction industry. About three-quarter of drawings, specifications and schedules were acquired through printed copy (paper based), and only about one-tenth of these information were acquired through email and disk/flash. While about four-fifth of the bills of quantities, claims and final account documents/information were being disseminated through the traditional paper-based printed copy, and less than one-tenth of these information are being disseminated through email and disk/flash. The order of IT adoption and use in information acquisition in the Nigerian Construction industry was found to be paper based medium, then followed by online medium, email and others (mobile) came third and fourth respectively, while disk/flash and came fifth and sixth in ranking. Furthermore, in contrast to the order of IT adoption and use in information acquisition in the Nigerian Construction industry, paper-based and disk/flash medium came first and second in order of information dissemination. Emails and online medium came 3rd and 4th in place, while fax and others (such as mobile phone), came 5th and 6th in adoption and use. Thus, for construction professionals in developing countries to reap the benefit of IT, it must go beyond the use of paper based medium to the use of IT tools for the acquisition and dissemination of information in the industry

Stance-taking and social status on an online bulletin board: A qualitative and quantitative approach

In this study, I demonstrate that social hierarchy and power are important aspects for understanding the use of epistemic and evidential stance verbs in computer-mediated communication. The data for the study come from an online bulletin board about rhythmic gymnastics, where the construction of social roles is believed to play a role in the expression of stance. The members of the community are divided into three hierarchically distinct social ranks based on status and activity on the board. I investigate whether members of a higher rank use epistemic and evidential stance verbs in a more authoritative manner than members of lower ranks using two methodological frameworks. In the qualitative part of the study, I adopt the dialogical discourse analysis to argue that epistemic and evidential stance is a dialogically constructed phenomenon that locally emerges between conversational co-participants. The quantitative part of the study employs the multifactorial usage-feature analysis, where two stance verbs think and seem are coded for a range of formal, semantic and extra-linguistic factors, which are believed to contribute to the differentiation of authoritative and tentative stance. The results show that bulletin board users of a higher rank exhibit a more authoritative and even aggressive use of epistemic and evidential stance verbs than users of lower ranks

The e-Robot Project: a longitudinal on-line research collaboration to investigate ERA principles

The Educational Robotic Application (ERA) Principles provides a framework for evaluating Educational Robots and their activities. This paper presents the rationale behind the proposed e-Robot Project, an online community based research resource aimed at gathering data on the use of educational robotics. Collating the data against ERA is an iterative process that will simultaneously verify and improve ERA, which in turn will inform the design and application of educational robotics. e-Robot involves all aspects of the research process from research design to meta-analysis. The project can run indefinitely and will encourage participation from student teachers, teachers, researchers, developers, administrators, politicians and other interested parties

Recognition Situations Using Extended Dempster-Shafer Theory

Weiser’s [111] vision of pervasive computing describes a world where technology seamlessly integrates into the environment, automatically responding to peoples’ needs. Underpinning this vision is the ability of systems to automatically track the situation of a person. The task of situation recognition is critical and complex: noisy and unreliable sensor data, dynamic situations, unpredictable human behaviour and changes in the environment all contribute to the complexity. No single recognition technique is suitable in all environments. Factors such as availability of training data, ability to deal with uncertain information and transparency to the user will determine which technique to use in any particular environment. In this thesis, we propose the use of Dempster-Shafer theory as a theoretically sound basis for situation recognition - an approach that can reason with uncertainty, but which does not rely on training data. We use existing operations from Dempster-Shafer theory and create new operations to establish an evidence decision network. The network is used to generate and assess situation beliefs based on processed sensor data for an environment. We also define two specific extensions to Dempster-Shafer theory to enhance the knowledge that can be used for reasoning: 1) temporal knowledge about situation time patterns 2) quality of evidence sources (sensors) into the reasoning process. To validate the feasibility of our approach, this thesis creates evidence decision networks for two real-world data sets: a smart home data set and an officebased data set. We analyse situation recognition accuracy for each of the data sets, using the evidence decision networks with temporal/quality extensions. We also compare the evidence decision networks against two learning techniques: Naïve Bayes and J48 Decision Tree

Diversity and power in the world city network

There are three purposes: (1) to illustrate diversity amongst world cities; (2) to show how this reflects/constitutes power relativities between cities; and (3) to place debates on diversity and power on a firm empirical basis. The power of cities is interpreted both as a capacity (‘power over’) and as a medium (‘power to’). World cities are treated as global service centres and the world city network is conceptualised as being ‘interlocked’ through provision of business and financial services by global firms. The study is primarily empirical and uses a global data set comprising information on 100 global service firms in 123 world cities. Seven different ways of measuring and illustrating power differentials are presented: global network connectivity, banking/finance connectivity, dominant centres, global command centres, regional command centres, high connectivity gateways, and gateways to emerging markets. These categories have been identified before but never specified as comprehensively and rigorously as here. Whereas power as command power is concentrated in the USA, western Europe and Tokyo, network power is much more geographically diffused transcending the old ‘North-South divide’. Finally the focus on diversity makes problematic the lazy policy tendency for emulation of a few well-known ‘global cities’