Giannis Tzimas

Prof. Giannis Tzimas


Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 October 2013 in Nucleic Acids Research
Verified
Journal Article
Open access
PDF file
BGBelinda Giardine
Belinda Giardine
JBJoseph Borg
Joseph Borg
EVEmmanouil Viennas
Emmanouil Viennas
CPCristiana Pavlidis
Cristiana Pavlidis
KMKamran Moradkhani
Kamran Moradkhani
George PatrinosGeorge Patrinos
George Patrinos
HbVar (http://globin.bx.psu.edu/hbvar) is one of the oldest and most appreciated locus-specific databases launched in 2001 by a multi-center academic effort to provide timely information on the genomic alterations leading to hemoglobin variants and all types of thalassemia and hemoglobinopathies. Database records include extensive phenotypic descriptions, biochemical and hematological effects, associated pathology and ethnic occurrence, accompanied by mutation frequencies and references. Here, we report updates to >600 HbVar entries, inclusion of population-specific data for 28 populations and 27 ethnic groups for α-, and β-thalassemias and additional querying options in the HbVar query page. HbVar content was also inter-connected with two other established genetic databases, namely FINDbase (http://www.findbase.org) and Leiden Open-Access Variation database (http://www.lovd.nl), which allows comparative data querying and analysis. HbVar data content has contributed to the realization of two collaborative projects to identify genomic variants that lie on different globin paralogs. Most importantly, HbVar data content has contributed to demonstrate the microattribution concept in practice. These updates significantly enriched the database content and querying potential, enhanced the database profile and data quality and broadened the inter-relation of HbVar with other databases, which should increase the already high impact of this resource to the globin and genetic database community.

12 October 2012 in Internet Research
Verified
Journal Article
Closed access
EFEvanthia Faliagka
Evanthia Faliagka
ATAthanasios Tsakalidis
Athanasios Tsakalidis
GTGiannis Tzimas
Giannis Tzimas
Purpose: The purpose of this paper is to present a novel approach for recruiting and ranking job applicants in online recruitment systems, with the objective to automate applicant pre‐screening. An integrated, company‐oriented, e‐recruitment system was implemented based on the proposed scheme and its functionality was showcased and evaluated in a real‐world recruitment scenario.Design/methodology/approach: The proposed system implements automated candidate ranking, based on objective criteria that can be extracted from the applicant's LinkedIn profile. What is more, candidate personality traits are automatically extracted from his/her social presence using linguistic analysis. The applicant's rank is derived from individual selection criteria using analytical hierarchy process (AHP), while their relative significance (weight) is controlled by the recruiter.Findings: The proposed e‐recruitment system was deployed in a real‐world recruitment scenario, and its output was validated by expert recruiters. It was found that with the exception of senior positions that required domain experience and specific qualifications, automated pre‐screening performed consistently compared to human recruiters.Research limitations/implications: It was found that companies can increase the efficiency of the recruitment process if they integrate an e‐recruitment system in their human resources management infrastructure that automates the candidate pre‐screening process. Interviewing and background investigation of applicants can then be limited to the top candidates identified from the system.Originality/value: To the best of the authors’ knowledge, this is the first e‐recruitment system that supports automated extraction of candidate personality traits using linguistic analysis and ranks candidates with the AHP.

11 July 2013 in Artificial Intelligence Review
Verified
Journal Article
Closed access
PDF file
EFEvanthia Faliagka
Evanthia Faliagka
Lazaros IliadisLazaros Iliadis
Lazaros Iliadis
Ioannis KarydisIoannis Karydis
Ioannis Karydis
Maria RigouMaria Rigou
Maria Rigou
Spyros SioutasSpyros Sioutas
Spyros Sioutas
GTGiannis Tzimas
Giannis Tzimas

26 June 2012 in Human Mutation
Verified
Journal Article
Open access
PDF file
George PatrinosGeorge Patrinos
George Patrinos
David N. CooperDavid N. Cooper
David N. Cooper
Erik MulligenErik Mulligen
Erik Mulligen
VGVassiliki Gkantouna
Vassiliki Gkantouna
GTGiannis Tzimas
Giannis Tzimas
BMBarend Mons
Barend Mons
The advances in bioinformatics required to annotate human genomic variants and to place them in public data repositories have not kept pace with their discovery. Moreover, a law of diminishing returns has begun to operate both in terms of data publication and submission. Although the continued deposition of such data in the public domain is essential to maximize both their scientific and clinical utility, rewards for data sharing are few, representing a serious practical impediment to data submission. To date, two main strategies have been adopted as a means to encourage the submission of human genomic variant data: (1) database journal linkups involving the affiliation of a scientific journal with a publicly available database and (2) microattribution, involving the unambiguous linkage of data to their contributors via a unique identifier. The latter could in principle lead to the establishment of a microcitation‐tracking system that acknowledges individual endeavor and achievement. Both approaches could incentivize potential data contributors, thereby encouraging them to share their data with the scientific community. Here, we summarize and critically evaluate approaches that have been proposed to address current deficiencies in data attribution and discuss ways in which they could become more widely adopted as novel scientific publication modalities. Hum Mutat 33:1503–1512, 2012.

4 March 2017 in Algorithms
Verified
Journal Article
Open access
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Andreas KanavosAndreas Kanavos
Andreas Kanavos
NNNikolaos Nodarakis
Nikolaos Nodarakis
Spyros SioutasSpyros Sioutas
Spyros Sioutas
ATAthanasios Tsakalidis
Athanasios Tsakalidis
DTDimitrios Tsolis
Dimitrios Tsolis
GTGiannis Tzimas
Giannis Tzimas
Sentiment Analysis on Twitter Data is indeed a challenging problem due to the nature, diversity and volume of the data. People tend to express their feelings freely, which makes Twitter an ideal source for accumulating a vast amount of opinions towards a wide spectrum of topics. This amount of information offers huge potential and can be harnessed to receive the sentiment tendency towards these topics. However, since no one can invest an infinite amount of time to read through these tweets, an automated decision making approach is necessary. Nevertheless, most existing solutions are limited in centralized environments only. Thus, they can only process at most a few thousand tweets. Such a sample is not representative in order to define the sentiment polarity towards a topic due to the massive number of tweets published daily. In this work, we develop two systems: the first in the MapReduce and the second in the Apache Spark framework for programming with Big Data. The algorithm exploits all hashtags and emoticons inside a tweet, as sentiment labels, and proceeds to a classification method of diverse sentiment types in a parallel and distributed manner. Moreover, the sentiment analysis tool is based on Machine Learning methodologies alongside Natural Language Processing techniques and utilizes Apache Spark’s Machine learning library, MLlib. In order to address the nature of Big Data, we introduce some pre-processing steps for achieving better results in Sentiment Analysis as well as Bloom filters to compact the storage size of intermediate data and boost the performance of our algorithm. Finally, the proposed system was trained and validated with real data crawled by Twitter, and, through an extensive experimental evaluation, we prove that our solution is efficient, robust and scalable while confirming the quality of our sentiment identification.

14 November 2013 in Nucleic Acids Research
Verified
Journal Article
Open access
PDF file
PPPetros Papadopoulos
Petros Papadopoulos
EVEmmanouil Viennas
Emmanouil Viennas
VGVassiliki Gkantouna
Vassiliki Gkantouna
CPCristiana Pavlidis
Cristiana Pavlidis
MBMarina Bartsakoulia
Marina Bartsakoulia
George PatrinosGeorge Patrinos
George Patrinos
FINDbase (http://www.findbase.org) aims to document frequencies of clinically relevant genomic variations, namely causative mutations and pharmacogenomic markers, worldwide. Each database record includes the population, ethnic group or geographical region, the disorder name and the related gene, accompanied by links to any related databases and the genetic variation together with its frequency in that population. Here, we report, in addition to the regular data content updates, significant developments in FINDbase, related to data visualization and querying, data submission, interrelation with other resources and a new module for genetic disease summaries. In particular, (i) we have developed new data visualization tools that facilitate data querying and comparison among different populations, (ii) we have generated a new FINDbase module, built around Microsoft’s PivotViewer (http://www.getpivot.com) software, based on Microsoft Silverlight technology (http://www.silverlight.net), that includes 259 genetic disease summaries from five populations, systematically collected from the literature representing the documented genetic makeup of these populations and (iii) the implementation of a generic data submission tool for every module currently available in FINDbase.