Challenges and opportunities in renovating public sector information by enabling linked data and analytics

Linked Data has become the current W3C recommended approach for publishing data on the World Wide Web as it is sharable, extensible, and easily re-usable. An ecosystem of linked data hubs in the Public Sector has the potential to offer significant benefits to its consumers (other public offices and ministries, as well as researchers, citizens and SMEs), such as increased accessibility and re-use value of their data through the use of web-scale identifiers and easy interlinking with datasets of other public data providers. The power and flexibility of the schema-defying Linked Data, however, is counterbalanced by inborn factors that diminish the potential for cost-effective and efficient adoption by the Public Sector. The paper analyzes these challenges in view of the current state-of-the-art in linked data technologies and proposes a technical framework that aims to hide the underlying complexity of linked data while maintaining and promoting the interlinking capabilities enabled by the Linked Data Paradigm. The paper presents the innovations behind our proposed solutions as well as their advantages, especially for the non-expert users.     

A Genetic Programming Approach for EUR/USD Exchange Rate Forecasting and Trading

The purpose of this article is to present a novel genetic programming trading technique in the task of forecasting the next day returns when trading the EUR/USD exchange rate based on the exchange rates of historical data. Aiming at testing its effectiveness, we benchmark the forecasting performance of our genetic programming implementation with three traditional strategies (naive strategy, MACD, and a buy & hold strategy) plus a hybrid evolutionary artificial neural network approach. The proposed genetic programming technique was found to demonstrate the highest trading performance in terms of annualized return and information ratio when compared to all other strategies which have been used. When more elaborate trading techniques, such as leverage, were combined with the examined models, the genetic programming approach still presented the highest trading performance. To the best of our knowledge, this is the first time that genetic programming is applied in the problem of effectively modeling and trading with the EUR/USD exchange rate. Our application now offers practitioners with an effective and extremely promising set of results when forecasting in the foreign exchange market. The developed genetic programming environment is implemented using the C++ programming language and includes a variation of the genetic programming algorithm with tournament selection.     

CloudsStorm: A framework for seamlessly programming and controlling virtual infrastructure functions during the DevOps lifecycle of cloud applications

The infrastructure-as-a-service (IaaS) model of cloud computing provides virtual infrastructure functions (VIFs), which allow application developers to flexibly provision suitable virtual machines' (VM) types and locations, and even configure the network connection for each VM. Because of the pay-as-you-go business model, IaaS provides an elastic way to operate applications on demand. However, in current cloud applications DevOps (software development and operations) lifecycle, the VM provisioning steps mainly rely on manually leveraging these VIFs. Moreover, these functions cannot be programmatically embedded into the application logic to control the infrastructure at runtime. Especially, the vendor lock-in issue, which different clouds provide different VIFs, also enlarges this gap between the cloud infrastructure management and application operation. To mitigate this gap, we designed and implemented a framework, CloudsStorm, which enables developers to easily leverage VIFs of different clouds and program them into their cloud applications. To be specific, CloudsStorm empowers applications with infrastructure programmability at design-level, infrastructure-level, and application-level. CloudsStorm also provides two infrastructure controlling modes, ie, active and passive mode, for applications at runtime. Besides, case studies about operating task-based and big data applications on clouds show that the monetary cost is significantly reduced through the seamless and on-demand infrastructure management provided by CloudsStorm. Finally, the scaling and recovery operation evaluations of CloudsStorm are performed to show its controlling performance. Compared with other tools, ie, “jcloud” and “cloudinit.d”, the scaling and provisioning performance evaluations demonstrate that CloudsStorm can achieve at least 10% efficiency improvement in our experiment settings.     

Solar tower power plant in Germany and future perspectives of the development of the technology in Greece and Cyprus

Since the 80s power production with solar thermal power plants has been a way to substitute fossil fuels. By concentrating direct solar radiation from heliostats very high temperatures of a thermal fluid can be reached. The resulting heat is converted to mechanical energy in a steam cycle which generates electricity.High efficiencies and fast start-up are reached by using air as a heat medium, as well as using porous ceramic materials as solar receiver of the concentrated sunlight.In Germany the construction of a 1.5 MW_e solar tower power plant began in 2008. It is operational since December 2008 and started production of electricity in the spring of 2009.In Greece and Cyprus, countries with high solar potential, the development of this competitive solar thermal technology is imperative, since it has already been implemented in other Mediterranean countries.     

A Diversified Library of Bacterial and Fungal Bifunctional Cytochrome P450 Enzymes for Drug Metabolite Synthesis

Innovative biohydroxylation catalysts for the preparation of drug metabolites were developed from scratch. A set of bacterial and fungal sequences of putative and already known bifunctional P450 enzymes was identified by protein sequence alignments, expressed in Escherichia coli and characterised. Notably, a fungal self‐sufficient cytochrome P450 (CYP) from Aspergillus fumigatus turned out to be especially stable during catalyst preparation and application and also in presence of organic co‐solvents. To enhance the catalytic activity and broaden the substrate specificity of those variants with high expression levels prominent single mutations were introduced. Selected improved variants were then used as lyophilised bacterial lysates for the synthesis of 4′‐hydroxydiclofenac and 6‐hydroxychlorzoxazone, the two metabolites of active pharmaceutical compounds diclofenac and chlorzoxazone representing the same metabolites as generated by human P450s.     

Comparative study of spontaneously fermented sourdoughs originating from two regions of Greece: Peloponnesus and Thessaly

A total of 167 yeast and 136 lactic acid bacteria strains were isolated from spontaneously fermented wheat sourdoughs from two regions of Greece, namely Thessaly and Peloponnesus. Identification of the isolates exhibited dominance of Torulaspora delbrueckii with sporadic presence of Saccharomyces cerevisiae and, regarding the lactic acid bacteria, dominance of Lactobacillus sanfranciscensis in the sourdoughs from Thessaly and Lb. plantarum subsp. plantarum in the sourdoughs from Peloponnesus. The latter was accompanied by Pediococcus pentosaceus as secondary microbiota. None of the above mentioned strains exhibited amylolytic, lipolytic or proteolytic activities, and none of the lactic acid bacteria strains produced antimicrobial compounds.     

Interactive Videoconferencing for collaborative learning at a distance in the school of 21st century: A case study in elementary schools in Greece

The aim of this paper is to present the design, implementation and evaluation of the methodology which focuses on the pedagogical utilization of Interactive Videoconferencing (IVC) in the contemporary elementary school.     

A Reasoning System of Ternary Projective Relations

This paper introduces a reasoning system based on a previously developed model for ternary projective relations between spatial objects. The model applies to spatial objects of the kind point and region is based on basic projective invariants and takes into account the size and shape of the three objects that are involved in a relation. The reasoning system proposes a set of permutation and composition rules, which allow the inference of unknown relations from given ones.