Papers by Theodosios Theodosiou
Procedia Economics and Finance, 2014
Procedia Economics and Finance, 2014
Consumers who prefer to make their shopping via Internet are continuously increasing. This paper ... more Consumers who prefer to make their shopping via Internet are continuously increasing. This paper investigates the relation of econsumers with the applications of e-commerce, their attitude when buying and their consuming satisfaction. The present study empirically investigates the e-consumers' perception regarding e-shopping. A sample of 168 consumers from three cities of Greece was used in order to answer a structured questionnaire regarding e-consumer behaviour. The results of the empirical research are presented and the relevant findings are discussed.
Aquatic Conservation: Marine and Freshwater Ecosystems, 2010
1. Cymodocea nodosa's leaf length distribution was studied as an easily measurable indicator to m... more 1. Cymodocea nodosa's leaf length distribution was studied as an easily measurable indicator to monitor and conserve Macedonian, North Aegean, Greek coastal habitats. 2. Three Cymodocea meadows off the eastern Kavala Gulf coast (Nea Karvali, Erateino, Agiasma), with that of Nea Karvali close to an industrial area being the most degraded, were sampled during the seagrass main growing season in July 2004. Two further meadows, one pristine to less degraded (Brasidas, Gulf of Kavala) and one degraded (Biamyl, Inner Thessaloniki Gulf), were sampled as benchmarks in July 2005. The results were evaluated using Gaussian fit curves, and non-parametric and nested parametric ANOVA on a hierarchy of spatial scales: area (tens of metres), site (hundreds of metres) and meadow (kilometres). 3. Frequency (%) distribution of leaf length values and CymoSkew index variation were best associated with anthropogenic stress. Frequency (%) distribution of adult and intermediate photosynthetic leaf length values revealed a unimodal distribution possible to be fitted, at least at pristine to less degraded meadows, by normal distribution (R 2 40.5). 4. Statistically significant variation was estimated for CymoSkew index, a quantitative expression of leaf length asymmetry, on the meadow scale (Po0.001). Biamyl (3.82) and Nea Karvali (3.64) were indicated as heavily degraded meadows, Erateino (2.93) as a degraded meadow, Agiasma (2.18) as a meadow with the first signs of degradation, and Brasidas (1.68) as a pristine to less degraded meadow. These results in combination with other meadow specific biotic parameters were used to suggest a preliminary angiosperm 'Ecological Status Classes' classification scheme useful for the implementation of WFD in the north Aegean Sea. 5. The CymoSkew index seems to respond to lower levels of stress than is needed for other more conservative plant modules and therefore, could be regarded as an early warning indicator of Cymodocea habitat degradation.
Efficient human resource management needs accurate assessment and representation of available com... more Efficient human resource management needs accurate assessment and representation of available competences as well as effective mapping of required competences for specific jobs and positions. In this regard, appropriate definition and identification of competence gaps express differences between acquired and required competences. Using a detailed quantification scheme together with a mathematical approach is a way to support accurate competence analytics, which can be applied in a wide variety of sectors and fields. This article describes the combined use of software technologies and mathematical and statistical methods for assessing and analyzing competences in human resource information systems. Based on a standard competence model, which is called a Professional, Innovative and Social competence tree, the proposed framework offers flexible tools to experts in real enterprise environments, either for evaluation of employees towards an optimal job assignment and vocational training...
Biomedical literature databases constitute valuable repositories of up to date scientific knowled... more Biomedical literature databases constitute valuable repositories of up to date scientific knowledge. The development of efficient classification methods in order to facilitate the organization of these databases and the extraction of novel biomedical knowledge is becoming increasingly important. Several of these methods use bio-ontologies, like Gene Ontology to concisely describe and classify biological documents. The purpose of this paper is to compare two classical statistical classification methods, namely multinomial logistic regression (MLR) and linear discriminant analysis (LDA), to a machine learning classification method, called support vector machines (SVM). Although all the methods have been used with success for classifying texts, there is not a direct comparison between them for classifying biological text to specific Gene Ontology terms. The results from the study show that LDA performs better (accuracy 80.32%) than SVM (77.18%) and MLR (57.4%). LDA not only performs we...
Best Practices in Online Education, 2013
In this chapter, issues concerning the role of Learning Management Systems in early childhood edu... more In this chapter, issues concerning the role of Learning Management Systems in early childhood education are discussed. To the best of the authors’ knowledge, such issues have not been thoroughly discussed till now in literature. Learning Management Systems in early childhood concern four types of users: pre-service teachers, in-service teachers, early childhood students and their parents. To a certain degree, each type of user affects the types of services and functionalities that have to be provided by a Learning Management System. Relevant case studies depicting Learning Management Systems role in different settings are presented. Requirements that Learning Management Systems should satisfy are also discussed. Practical issues and guidelines concerning the use of the open source Learning Management System Moodle are also presented. Lastly, future research directions are outlined.
In this paper we present a framework for conducting electronic elections over the web taking into... more In this paper we present a framework for conducting electronic elections over the web taking into consideration the legal consequences. The proposed system has to be based on open source software with its own security protocol. It will be an alternative and practical solution to existing e-voting systems applications not only for communities, universities and organizations but for national and communities elections as well. Key-Words: E-voting, Electronic Election Systems, Requirements, Types, Legal Aspects, Technical Aspects
Nucleic Acids Research, 2021
Bottom-up proteomics analyses have been proved over the last years to be a powerful tool in the c... more Bottom-up proteomics analyses have been proved over the last years to be a powerful tool in the characterization of the proteome and are crucial for understanding cellular and organism behaviour. Through differential proteomic analysis researchers can shed light on groups of proteins or individual proteins that play key roles in certain, normal or pathological conditions. However, several tools for the analysis of such complex datasets are powerful, but hard-to-use with steep learning curves. In addition, some other tools are easy to use, but are weak in terms of analytical power. Previously, we have introduced ProteoSign, a powerful, yet user-friendly open-source online platform for protein differential expression/abundance analysis designed with the end-proteomics user in mind. Part of Proteosign's power stems from the utilization of the well-established Linear Models For Microarray Data (LIMMA) methodology. Here, we present a substantial upgrade of this computational resource...
A huge amount of data is produced in our days in the agriculture sector. Due to the huge amount o... more A huge amount of data is produced in our days in the agriculture sector. Due to the huge amount of this datasets it is necessary to use data mining techniques in order to comprehend the data and extract useful information. In our work we apply three different data mining techniques to data about Olea europaea var. media oblonga from the island of Thassos, at the northern part of Greece. The data were from 1063 farmers from three different municipalities of Thassos, namely Kallirachi, Limenaria and Prinos and concerned 2010. They were analysed using the classification algorithm OneR, the clustering algorithm k-means and the association rule mining algorithm, Apriori from the WEKA data mining package. The results indicate that organic cultivation could improve the production of olives and olive oil.
Analyzing Healthcare Data of Immigrants from the General Hospitals of East Macedonia and Trace
International Review of Management and Business Research, 2015
IntroductionThe number of immigrants entering the European Union countries the last couple of yea... more IntroductionThe number of immigrants entering the European Union countries the last couple of years has been increased dramatically (Vasileva, 20012). Greece is one of the EU countries accepting a substantial proportion of the immigrants. Migratory flows to Greece began in the early 90s in response to the radical upheavals in Eastern Europe. A small portion of incoming immigrants were political refugees from Eastern Europe, while the largest part of the incoming people were economic immigrants were seeking in the booming then Greece better living conditions and employment. The flows of immigrants were relatively stable and high during the decades of '90 and '00. At the end of the last decade they have relatively weakened due to the economic crisis in Greece. It is noteworthy that in recent years there are significant movements of refugees to Greece from the areas southern of Greece due the war situation in many countries in the southern regions (Afghanistan, Iraq, Syria, N. ...
Analysing the Cost of Immigrants to the National Health System in Eastern Macedonia and Thrace
World Academy of Science, Engineering and Technology, International Journal of Humanities and Social Sciences, 2015
The latest years the number of immigrants at Greece has increased dramatically. Their impact on t... more The latest years the number of immigrants at Greece has increased dramatically. Their impact on the National Health System (NHS) has not been yet thoroughly investigated. This paper analyses the cost of immigrants to the NHS hospitals of the region of Eastern Macedonia and Thrace. The data are collected from 2005 to 2011 from five different hospitals and are analysed using linear mixed effects models in order to investigate the effects of nationality and year on the cost of hospitalization and treatment. The results show that generally the Greek nationality patients have a higher mean cost of hospitalization compared to the immigrants and that there is an increasing trend for the cost except for the year 2010. Keywords—Cost, Eastern Macedonia, Thrace, immigrants, national health system.
EMBnet.journal
In this article we present the Network Analysis Profiler (NAP v2.0), a web tool to directly compa... more In this article we present the Network Analysis Profiler (NAP v2.0), a web tool to directly compare the topological features of multiple networks simultaneously. NAP is written in R and Shiny and currently offers both 2D and 3D network visualisation, as well as simultaneous visual comparisons of node- and edge-based topological features as bar charts or scatterplot matrix. NAP is fully interactive, and users can easily export and visualise the intersection between any pair of networks using Venn diagrams or a 2D and a 3D multi-layer graph-based visualisation. NAP supports weighted, unweighted, directed, undirected and bipartite graphs.
A Web e-voting system with a data analysis component
Journal of Systems and Information Technology
Purpose Currently, electronic election is one of the most popular issues of e-democracy. This has... more Purpose Currently, electronic election is one of the most popular issues of e-democracy. This has led to the development of applications and several security mechanisms to address such necessity. The problem that arises is that such applications are created either on demand for a specific election process, or experimentally for scientific purposes. The purpose of this study is to present a new e-voting system, called VOTAN. The VOTAN system involves a combination of new features with basic advantages, the implementation as open source software, its modular organization covering the functional requirements of a typical electronic voting system (EVS) and the capability of data analysis of candidates and voters. Design/methodology/approach VOTAN stands for VOTes Analyzer. It is a secure application for the conduct of electronic elections through the internet based on its own security protocol. It also includes a data analysis component which analyzes the election results and investigat...
International journal of economics and finance, 2011
Since the beginning of the 90s, Greece has rapidly become a reception country of a significant nu... more Since the beginning of the 90s, Greece has rapidly become a reception country of a significant number of immigrants. It is estimated that, nowadays, the number of immigrants, both legal and illegal, is approximately 1,2 million. At the same time, Greece is, moreover, being used as an intermediate, temporary station in the immigrants’ effort to reach the countries of the central Europe. Consequently, the existing migration stock of Greece is too significant to be left unexamined, especially since various previous researches indicate that a considerable number of immigrants express their intention to make Greece their place of permanent residence. Therefore, the application of an integration immigration policy in Greek society is considered to be a necessity and the examination of the parameters that will support its effectiveness rises as an important practical issue. The present study empirically investigates the main factors that compose, according to relevant literature, the immig...
BMC Research Notes
Objective: Nowadays, due to the technological advances of high-throughput techniques, Systems Bio... more Objective: Nowadays, due to the technological advances of high-throughput techniques, Systems Biology has seen a tremendous growth of data generation. With network analysis, looking at biological systems at a higher level in order to better understand a system, its topology and the relationships between its components is of a great importance. Gene expression, signal transduction, protein/chemical interactions, biomedical literature co-occurrences, are few of the examples captured in biological network representations where nodes represent certain bioentities and edges represent the connections between them. Today, many tools for network visualization and analysis are available. Nevertheless, most of them are standalone applications that often (i) burden users with computing and calculation time depending on the network's size and (ii) focus on handling, editing and exploring a network interactively. While such functionality is of great importance, limited efforts have been made towards the comparison of the topological analysis of multiple networks. Results: Network Analysis Provider (NAP) is a comprehensive web tool to automate network profiling and intra/internetwork topology comparison. It is designed to bridge the gap between network analysis, statistics, graph theory and partially visualization in a user-friendly way. It is freely available and aims to become a very appealing tool for the broader community. It hosts a great plethora of topological analysis methods such as node and edge rankings. Few of its powerful characteristics are: its ability to enable easy profile comparisons across multiple networks, find their intersection and provide users with simplified, high quality plots of any of the offered topological characteristics against any other within the same network. It is written in R and Shiny, it is based on the igraph library and it is able to handle medium-scale weighted/unweighted, directed/undirected and bipartite graphs. NAP is available at http:// bioinformatics.med.uoc.gr/NAP.
Nucleic acids research, Jan 17, 2017
Profiling of proteome dynamics is crucial for understanding cellular behavior in response to intr... more Profiling of proteome dynamics is crucial for understanding cellular behavior in response to intrinsic and extrinsic stimuli and maintenance of homeostasis. Over the last 20 years, mass spectrometry (MS) has emerged as the most powerful tool for large-scale identification and characterization of proteins. Bottom-up proteomics, the most common MS-based proteomics approach, has always been challenging in terms of data management, processing, analysis and visualization, with modern instruments capable of producing several gigabytes of data out of a single experiment. Here, we present ProteoSign, a freely available web application, dedicated in allowing users to perform proteomics differential expression/abundance analysis in a user-friendly and self-explanatory way. Although several non-commercial standalone tools have been developed for post-quantification statistical analysis of proteomics data, most of them are not end-user appealing as they often require very stringent installation...
Expert Systems with Applications, 2017
Efficient human resource management needs accurate assessment and representation of available com... more Efficient human resource management needs accurate assessment and representation of available competences as well as effective mapping of required competences for specific jobs and positions. In this regard, appropriate definition and identification of competence gaps express differences between acquired and required competences. Using a detailed quantification scheme together with a mathematical approach is a way to support accurate competence analytics, which can be applied in a wide variety of sectors and fields. This article describes the combined use of software technologies and mathematical and statistical methods for assessing and analyzing competences in human resource information systems. Based on a standard competence model, which is called a Professional, Innovative and Social competence tree, the proposed framework offers flexible tools to experts in real enterprise environments, either for evaluation of employees towards an optimal job assignment and vocational training or for recruitment processes. The system has been tested with real human resource data sets in the frame of the European project called ComProFITS.
BMC Bioinformatics, 2016
Background: Text mining and data integration methods are gaining ground in the field of health sc... more Background: Text mining and data integration methods are gaining ground in the field of health sciences due to the exponential growth of bio-medical literature and information stored in biological databases. While such methods mostly try to extract bioentity associations from PubMed, very few of them are dedicated in mining other types of repositories such as chemical databases. Results: Herein, we apply a text mining approach on the DrugBank database in order to explore drug associations based on the DrugBank "Description", "Indication", "Pharmacodynamics" and "Mechanism of Action" text fields. We apply Name Entity Recognition (NER) techniques on these fields to identify chemicals, proteins, genes, pathways, diseases, and we utilize the TextQuest algorithm to find additional biologically significant words. Using a plethora of similarity and partitional clustering techniques, we group the DrugBank records based on their common terms and investigate possible scenarios why these records are clustered together. Different views such as clustered chemicals based on their textual information, tag clouds consisting of Significant Terms along with the terms that were used for clustering are delivered to the user through a user-friendly web interface.
Application of Data Mining Techniques to Olea europaea var. media oblonga production from Thassos Island
ABSTRACT A huge amount of data is produced in our days in the agriculture sector. Due to the huge... more ABSTRACT A huge amount of data is produced in our days in the agriculture sector. Due to the huge amount of this datasets it is necessary to use data mining techniques in order to comprehend the data and extract useful information. In our work we apply three different data mining techniques to data about Olea europaea var. media oblonga from the island of Thassos, at the northern part of Greece. The data were from 1063 farmers from three different municipalities of Thassos, namely Kallirachi, Limenaria and Prinos and concerned 2010. They were analysed using the classification algorithm OneR, the clustering algorithm k-means and the association rule mining algorithm, Apriori from the WEKA data mining package. The results indicate that organic cultivation could improve the production of olives and olive oil.
International Journal of Medical Informatics, 2007
Background: Functional annotation of genes is an important task in biology since it facilitates t... more Background: Functional annotation of genes is an important task in biology since it facilitates the characterization of genes relationships and the understanding of biochemical pathways. The various gene functions can be described by standardized and structured vocabularies, called bio-ontologies. The assignment of bio-ontolgy terms to genes is carried out by means of applying certain methods to datasets extracted from biomedical articles. These methods originate from data mining and machine learning and include maximum entropy or support vector machines (SVM).
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Papers by Theodosios Theodosiou