University of the Aegean

About: University of the Aegean is a education organization based out in Mytilene, Greece. It is known for research contribution in the topics: Population & Context (language use). The organization has 2818 authors who have published 8100 publications receiving 179275 citations. The organization is also known as: UAEG.

Preference Learning for Cognitive Modeling: A Case Study on Entertainment Preferences

Abstract: Learning from preferences, which provide means for expressing a subject's desires, constitutes an important topic in machine learning research. This paper presents a comparative study of four alternative instance preference learning algorithms (both linear and nonlinear). The case study investigated is to learn to predict the expressed entertainment preferences of children when playing physical games built on their personalized playing features ( entertainment modeling). Two of the approaches are derived from the literature-the large-margin algorithm (LMA) and preference learning with Gaussian processes-while the remaining two are custom-designed approaches for the problem under investigation: meta-LMA and neuroevolution. Preference learning techniques are combined with feature set selection methods permitting the construction of effective preference models, given suitable individual playing features. The underlying preference model that best reflects children preferences is obtained through neuroevolution: 82.22% of cross-validation accuracy in predicting reported entertainment in the main set of game survey experimentation. The model is able to correctly match expressed preferences in 66.66% of cases on previously unseen data (p -value = 0.0136) of a second physical activity control experiment. Results indicate the benefit of the use of neuroevolution and sequential forward selection for the investigated complex case study of cognitive modeling in physical games.

Multivariate Mixed Models for Open-Ended Contingent Valuation Data: Willingness To Pay For Conservation of Monk Seals

Abstract: Although dichotomous choice (DC) contingent valuation (CV) has been recommended by the US NOAA 'blue-ribbon' panel for large-scale contingent valuation studies, useful information can still be obtained from smaller, open-ended (OE) studies, often undertaken as a precursor to a DC survey. The CV study considered here was carried out in Greece and looked at willingness-to-pay (WTP) for protecting the Mediterranean monk seal (Monachus-monachus) in the Aegean area. This is the most endangered seal in the world, and the application of the CV methodology was the first such application in Greece. The OE data consist of two responses: first, a binary response detailing whether or not respondents were in principle prepared to pay for the protection of this seal; secondly, those respondents who answered 'yes' to the first question were then asked to state their maximum WTP for such protection. A multivariate binomial – log-normal mixture model is used to develop a bid function including explanatory variables such as income, sex, age and education. Such a modelling approach provides an alternative to more commonplace tobit estimation. However, the model is extended to include further information which was collected on: (a) an increased WTP amount given in response to information that the initial WTP amount may not be enough to prevent the extinction of the seal; (b) respondents were asked to divide their final WTP amount between use, option and existence values, the latter requiring a multivariate model with four binary and four continuous responses per individual in the same model. The discussion focuses on the methodological issues raised with some comment on the substantive interpretation of results.

Participative Public Policy Making Through Multiple Social Media Platforms Utilization

Abstract: Described is the research concerning the systematic, intensive and centralized web 2.0 social media exploitation by government agencies for widening and enhancing participative public policy making, which is conducted as part of the research project PADGETS 'Policy Gadgets Mashing Underlying Group Knowledge in Web 2.0 Media' partially funded by the European Commission. The proposed approach is based on a central system, which publishes various types of policy-related content e.g., short text long text, images, video and micro-applications in multiple social media simultaneously, and also collects from them and processes data on citizens' interactions e.g., views, comments, ratings, votes, etc.. Posing difficult research questions and challenges, both technical analysis and exploitation of social media application programming interfaces APIs, appropriate design of the central system architecture, processing and integrating the large amounts of collected citizens' interaction data and also non-technical investigation of the value generated by this approach, preconditions for its effective application by government agencies, which are researched in the above project. Some first findings on them are presented and discussed.

The MIS 11 – MIS 1 analogy, southern European vegetation, atmospheric methane and the "early anthropogenic hypothesis"

Abstract: . Marine Isotope Stage (MIS) 11 has been considered a potential analogue for the Holocene and its future evolution. However, a dichotomy has emerged over the precise chronological alignment of the two intervals, with one solution favouring a synchronization of the precession signal and another of the obliquity signal. The two schemes lead to different implications over the natural length of the current interglacial and the underlying causes of the evolution of greenhouse gas concentrations. Here, the close coupling observed between changes in southern European tree populations and atmospheric methane concentrations in previous interglacials is used to evaluate the natural vs. anthropogenic contribution to Holocene methane emissions and assess the two alignment schemes. Comparison of the vegetation trends in MIS 1 and MIS 11 favours a precessional alignment, which would suggest that the Holocene is nearing the end of its natural course. This, combined with the divergence between methane concentrations and temperate tree populations after 5 kyr BP, provides some support for the notion that the Holocene methane trend may be anomalous compared to previous interglacials. In contrast, comparison of MIS 1 with MIS 19, which may represent a closer astronomical analogue than MIS 11, leads to substantially different conclusions on the projected natural duration of the current interglacial and the extent of the anthropogenic contribution to the Holocene methane budget. As answers vary with the choice of analogue, resolution of these issues using past interglacials remains elusive.