Can social microblogging be used to forecast intraday exchange rates?

The Efficient Market Hypothesis (EMH) is widely accepted to hold true under certain assumptions. One of its implications is that the prediction of stock prices at least in the short run cannot outperform the random walk model. Yet, recently many studies stressing the psychological and social dimension of financial behavior have challenged the validity of the EMH. Towards this aim, over the last few years, internet-based communication platforms and search engines have been used to extract early indicators of social and economic trends. Here, we used Twitter's social networking platform to model and forecast the EUR/USD exchange rate in a high-frequency intradaily trading scale. Using time series and trading simulations analysis, we provide some evidence that the information provided in social microblogging platforms such as Twitter can in certain cases enhance the forecasting efficiency regarding the very short (intradaily) forex.Comment: This is a prior version of the paper published at NETNOMICS. The final publication is available at http://www.springer.com/economics/economic+theory/journal/1106

Domain-Driven Design and Soft Systems Methodology as a Framework to Avoid Software Crises

Crisis is considered to be an issue concerning complex systems like societies, organizations or even families. It can be defined as the situation in which the system functions poorly, the causes of the dysfunction are not immediately identified and immediate decisions need to be made. The type and the duration of a crisis may require different kinds of decision making. In a long-term crisis, when system changes may be required, the active participation of the affected people may be more important than the power and dynamics of the leadership. Software crises, in their their contemporary form as oganizational maffunctions, can still affect the viability of any organization. In this contribution we highlight the systemic aspects of a crisis, the complexity behind that and the role of systemic methodologies to explore its root causes and to design effective interventions. Our focus is on modeling as a means to simplify the complexity of the regarded phenomena and to build a knowledge consensus among stakeholders. Domain-Driven Design comes from software as an approach to deal with complex projects. It is based on models exploration in a creative collaboration between domain practitioners and solution providers. SSM is an established methodology for dealing with wicked situations. It incorporates the use of models and, along with Domain-Driven Design and other systemic methodologies can be employed to develop a common perception of the situation and a common language between interested parties in a crisis situation

Systemic modeling and relations thinking for risk assessment and IT resources alignment

Systems of any kind expose behaviors that are not directly related to the individual attributes or behaviors of their constituting elements. These are known as emergent behaviors and their existence is a challenge for the manager who oversees an organization or when an intervention is attempted. In this study we argue that interactions or relations provide the main contribution to the existence of the emergent properties and studying these relations can be the starting point for examining or assessing emergent properties or behaviors. Two typical examples of emergent behaviors in an organization which operates as a sociotechnical system are: (a) risk and opportunities and (b) the effectiveness of the information systems. The most systemic organizational paradigms are management systems following an ISO management standard, like ISO 9001:2015. Thus, our approach is aimed at systems of this type

Effects of multimedia computer-assisted instruction (MCAI) on academic achievement in physical education of Greek primary students

Computer technology has become an integral part of physical education, yet there have been few studies exploring the use of multimedia technology in the instruction of Physical Education. The purpose of this study was to investigate if Computer Assisted Instruction (CAI) in Physical Education is functional in the school environment. An interactive multimedia CD-ROM program was developed, especially for the needs of the study, titled «The tree of Health». This intervention trial involved 12 fifth- and sixthgrade classes (N = 248 students), randomized into 3 groups: Multimedia Computer Assisted Instruction, Traditional Approach to teaching (TA), and Control. Students were tested using pre and post-tests that measured knowledge of «Health related fitness» subjects. The experiment lasted 12 class hours, two classes per week over six weeks. The results of an analysis of covariance indicated that there was a significant increase in achievement post-test for the (MCAI) group when compared to either the (TA) or control groups, F(1, 238) = 13.486, p < .0167; F(1, 238) = 53.872, p < .0167. These results indicate that this new educational tool is an effective way to introduce health-related physical education programs for young students in typical classroom settings.Computer technology has become an integral part of physical education, yet there have been few studies exploring the use of multimedia technology in the instruction of Physical Education. The purpose of this study was to investigate if Computer Assisted Instruction (CAI) in Physical Education is functional in the school environment. An interactive multimedia CD-ROM program was developed, especially for the needs of the study, titled «The tree of Health». This intervention trial involved 12 fifth- and sixthgrade classes (N = 248 students), randomized into 3 groups: Multimedia Computer Assisted Instruction, Traditional Approach to teaching (TA), and Control. Students were tested using pre and post-tests that measured knowledge of «Health related fitness» subjects. The experiment lasted 12 class hours, two classes per week over six weeks. The results of an analysis of covariance indicated that there was a significant increase in achievement post-test for the (MCAI) group when compared to either the (TA) or control groups, F(1, 238) = 13.486, p < .0167; F(1, 238) = 53.872, p < .0167. These results indicate that this new educational tool is an effective way to introduce health-related physical education programs for young students in typical classroom settings

Application of chemometric methods for assessment and modelling of microbiological quality data concerning coastal bathing water in Greece

Background. Worldwide, the aim of managing water is to safeguard human health whilst maintaining sustainable aquatic and associated terrestrial, ecosystems. Because human enteric viruses are the most likely pathogens responsible for waterborne diseases from recreational water use, but detection methods are complex and costly for routine monitoring, it is of great interest to determine the quality of coastal bathing water with a minimum cost and maximum safety. Design and methods. This study handles the assessment and modelling of the microbiological quality data of 2149 seawater bathing areas in Greece over 10-year period (1997-2006) by chemometric methods. Results. Cluster analysis results indicated that the studied bathing beaches are classified in accordance with the seasonality in three groups. Factor analysis was applied to investigate possible determining factors in the groups resulted from the cluster analysis, and also two new parameters were created in each group; VF1 includes E. coli, faecal coliforms and total coliforms and VF2 includes faecal streptococci/enterococci. By applying the cluster analysis in each seasonal group, three new groups of coasts were generated, group A (ultraclean), group B (clean) and group C (contaminated). Conclusions. The above analysis is confirmed by the application of discriminant analysis, and proves that chemometric methods are useful tools for assessment and modeling microbiological quality data of coastal bathing water on a large scale, and thus could attribute to effective and economical monitoring of the quality of coastal bathing water in a country with a big number of bathing coasts, like Greece