Network-based ranking in social systems: three challenges

Ranking algorithms are pervasive in our increasingly digitized societies, with important real-world applications including recommender systems, search engines, and influencer marketing practices. From a network science perspective, network-based ranking algorithms solve fundamental problems related to the identification of vital nodes for the stability and dynamics of a complex system. Despite the ubiquitous and successful applications of these algorithms, we argue that our understanding of their performance and their applications to real-world problems face three fundamental challenges: (i) Rankings might be biased by various factors; (2) their effectiveness might be limited to specific problems; and (3) agents' decisions driven by rankings might result in potentially vicious feedback mechanisms and unhealthy systemic consequences. Methods rooted in network science and agent-based modeling can help us to understand and overcome these challenges.Comment: Perspective article. 9 pages, 3 figure

The Use of Computational Methods in the Toxicological Assessment of Chemicals in Food: Current Status and Future Prospects

A wide range of chemicals are intentionally added to, or unintentially found in, food products, often in very small amounts. Depending on the situation, the experimental data needed to complete a dietary risk assessment, which is the scientific basis for protecting human health, may not be available or obtainable, for reasons of cost, time and animal welfare. For example, toxicity data are often lacking for the metabolites and degradation products of pesticide active ingredients. There is therefore an interest in the development and application of efficient and effective non-animal methods for assessing chemical toxicity, including Quantitative Structure-Activity Relationship (QSAR) models and related computational methods. This report gives an overview of how computational methods are currently used in the field of food safety by national regulatory bodies, international advisory organisations and the food industry. On the basis of an international survey, a comprehensive literature review and a detailed QSAR analysis, a range of recommendations are made with the long-term aim of promoting the judicious use of suitable QSAR methods. The current status of QSAR methods is reviewed not only for toxicological endpoints relevant to dietary risk assessment, but also for Absorption, Distribution, Metabolism and Excretion (ADME) properties, which are often important in discriminating between the toxicological profiles of parent compounds and their reaction products. By referring to the concept of the Threshold of Toxicological Concern (TTC), the risk assessment context in which QSAR methods can be expected to be used is also discussed. This Joint Research Centre (JRC) Reference Report provides a summary and update of the findings obtained in a study carried out by the JRC under the terms of a contract awarded by the European Food Safety Authority (EFSA).JRC.DG.I.6-Systems toxicolog

Web Acceptance and Usage Model: A Comparison between Goal-directed and Experiential Web Users

In this paper we analyse the Web acceptance and usage between goal-directed users and experiential users, incorporating intrinsic motives to improve the particular and explanatory TAM value –traditionally related to extrinsic motives-. A field study was conducted to validate measures used to operationalize model variables and to test the hypothesised network of relationships. The data analysis method used was Partial Least Squares (PLS).The empirical results provided strong support for the hypotheses, highlighting the roles of flow, ease of use and usefulness in determining the actual use of the Web among experiential and goal-directed users. In contrast with previous research that suggests that flow would be more likely to occur during experiential activities than goal-directed activities, we found clear evidence of flow for goal-directed activities. In particular the study findings indicate that flow might play a powerfulrole in determining the attitude towards usage,intention to useand, in turn,actual Web use among experiential and goal-directed users

The interaction of lean and building information modeling in construction

Lean construction and Building Information Modeling are quite different initiatives, but both are having profound impacts on the construction industry. A rigorous analysis of the myriad specific interactions between them indicates that a synergy exists which, if properly understood in theoretical terms, can be exploited to improve construction processes beyond the degree to which it might be improved by application of either of these paradigms independently. Using a matrix that juxtaposes BIM functionalities with prescriptive lean construction principles, fifty-six interactions have been identified, all but four of which represent constructive interaction. Although evidence for the majority of these has been found, the matrix is not considered complete, but rather a framework for research to explore the degree of validity of the interactions. Construction executives, managers, designers and developers of IT systems for construction can also benefit from the framework as an aid to recognizing the potential synergies when planning their lean and BIM adoption strategies

A strategic theoretical framework to safeguard business value for information systems

The phenomenon of business value dissipation in mature organisations as an unintended by-product of the adoption and use of information systems has been a highly debated topic in the corporate boardroom awakening the interest of practitioners and academics alike. Much of the discourse tends to focus on the inability of organisations to unlock and realise the intended benefits to be harvested through large information systems investments. While the business case for investing in large technology programmes has been thoroughly investigated, the human agent that causes value erosion through his interaction with information systems (IS), has not received the studied attention it deserves. This study examines the use of technology in organisations by considering the dichotomy inherent in IS where its introduction for the purposes of creating new or sustaining existing business value subsequently also inadvertently dissipates value. The study proceeds to investigate the root people-induced causes resulting in the unintentional dissipation of value and presents an empirically validated model suggesting that human agents do not only create value for organisations through their use of IS, but at the same time, deliberately or inadvertently, dissipate value. The root people-induced causes resulting in the unintentional dissipation of value is delineated within a Theoretical Technology Value Framework that is constructed from a review of the extant literature, and delineates the overall unintentional value destroying causes and effects of IS on organisations. The Theoretical Technology Value Framework is forthwith applied as a basis for the development of a set of questions to support both qualitative and quantitative investigations from which an Archetypical Technology Value Model was derived. Finally, an Archetypical Technology Value Model is presented as a benchmark and basis to identify, investigate, mitigate and minimise or eliminate the unintentional value destroying effects of IS on Information Technology driven organisations. The study concludes with implications for both theory and practice and suggestions on how value erosion through the activities of the human agent may be identified, modeled and mitigated. Ultimately, recommendations are offered towards the crafting of more effective IS.School of ComputingPh. D. (Information Systems