The bergman kernel method for the numerical conformal mapping of simply connected domains

A numerical method for the conformal mapping of simply-connected domains onto the unit disc is considered. The method is based on the use of the Bergman kernel function of the domain. It is shown that, for a successful application, the basis of the series representation of the kernel must include terms that reflect the main singular behaviour of the kernel in the complement of the domain

An orthonormalization method for the approximate conformal mapping of multiply-connected domains

We consider the use of an orthonormalization method for constructing approximations to one of the standard conformal maps for multiply-connected domains. The method has been used successfully in [12], but only for the mapping of doubly-connected domains. Our purpose here is to consider its application to the mapping of domains whose connectivity is greater than two

Studying How E-Markets Evaluation Can Enhance Trust in Virtual Business Communities

One of the major drawbacks of conducting business online is the raised level of risk associated with business transactions. Potential business partners usually have limited information about each others reliability or product / service quality before an online transaction. In this paper, we focus on the problem of selecting a trustful electronic market (e-market), in order to perform business transactions with it. In particular, we examine how the decision of selecting an appropriate e-market can be facilitated by an e-market recommendation algorithm. For this purpose, a metadata model for collecting and storing e-market evaluations from the members of a virtual business community in a reusable and interoperable manner is introduced. Then, an e-market recommendation algorithm that can synthesize existing e-market evaluations stored using the metadata model, is designed. Finally, a scenario of how the presented e-market recommendation algorithm can support a virtual agribusiness community of the organic agriculture sector is discussed.E-market, metadata, recommender system, virtual community, Institutional and Behavioral Economics, Marketing,

A Survey of Greek Agricultural E-Markets

The role that information technology plays in today’s business activities has led to an increase in firms using and/or deploying e-markets online. This development undoubtedly affects the agri-food sector, since a large number of agricultural firms are demonstrating or are expected to demonstrate e-commerce activities. This paper aims to provide an overview of the current status of agricultural e-markets in Greece, by presenting results from an analysis of 100 cases. Results indicate that Greek e-markets may still have a rather low degree of sophistication, but they demonstrate a strong B2B orientation, as well as an outreach for international customer bases.Internet, e-commerce, e-markets, agriculture, agri-food sector, survey, Consumer/Household Economics, Marketing,

Aptitude measurement: is measurement validity compromised in the morning

The purpose of the present study was to evaluate the reliability and validity of the General Aptitude Test (GAT), a national instrument for the measurement of aptitude/achievement in the Kingdom of Saudi Arabia as a function of daytime testing. Participants were 722 students who took on the GAT across morning and evening administrations in a within-person pre-post design. Participants were matched for gender, parental education, and test center characteristics (i.e., size). The GAT was tested for its psychometric properties and its measurement invariance across time of day. Results pointed to a significant misfit using an exact invariance protocol. Specifically, there was a large number of non-invariant items pointing to Differential Item Functioning (DIF). Second, internal consistency reliabilities were consistently lower during morning testing compared to evening testing as evidenced using both statistical and visual means. Concerns about dimensionality were also raised for the morning compared to the evening administration. Last, comparison of performance levels indicated that morning testing was associated with significant decrements in performance across all domains compared to performance levels during evening testing. The results have implications for the validity of measurement and public testing policy if test validity during morning administration is compromised

Developing a smartphone app for m-government in agriculture

The high penetration of smartphones and the advanced capabilities of the software that they can host, forces public agencies to rapidly transform their services in the mobile government environment for maximizing utility of services and minimizing costs. In this context, the aim of the paper is primarily to review the smartphone use and capabilities in agriculture. An overview of apps targeted to the agricultural business sector is provided. Secondly, the potential use of smartphones for mobile government is discussed and a transactional mobile government app for the Android operating system is proposed based on a case study for agriculture. The mobile government app is based on a previously developed electronic government system for farmers. Design and technical aspects for the implementation of the proposed app are presented and discussed. Such apps seem to be a promising solution for farmers enabling them to access government information and transact with public agencies at their convenience and at a location of their choice.</jats:p

ICT and farmers : lessons learned and future developments

Information and Communication Technologies (ICT) evolution is well advancing Moore?s Law prediction of geometric progression of computer performance indexes. Indeed, these technologies are not only fast developed but, in addition, are giving birth to newer ones nicely branching existing “old fashion” ICT systems and tools. These innovations of ICT are not only regenerating traditional sciences, like Agriculture, and practices, like farming, but also, awake well neglected human sensitiveness and indifference for poverty, environmental protection, climatic deterioration issues and the future of our planet as a whole. To refer to a few examples of these innovations affecting Agriculture and Environmental Sciences: Cloud Computing provides equality in resources management and exploitability to small budget farms against the big ones. Web2 browser allows, as a platform, effective runtime environment and considerably easy access to applications by farmers lacking proper education and training. Parallel Computing brings exponentially increased core processing to low-end computers facilitating the use of huge computer power by small agricultural research units. Never the less agricultural and farming communities, in their majority, do not adopt new ICT tools and systems to the degree required for substantial agricultural development. In this paper, experience gained over the years is used to evaluate and reason poor performance in the area of applicability of ICT innovations and tools by the vast majority of farmers throughout the world.</jats:p