# Δημοσιεύσεις

### 2020

#### Journal Articles

 D. Geromichalos, M.Azkarate, E. Tsardoulias, L. Gerdes, L. Petrou and C. Perez Del Pulgar Journal of Field Robotics, pp. 1-18, 2020 Feb This paper describes a novel approach to simultaneous localization and mapping (SLAM) techniques applied to the autonomous planetary rover exploration scenario to reduce both the relative and absolute localization errors, using two well‐proven techniques: particle filters and scan matching. Continuous relative localization is improved by matching high‐resolution sensor scans to the online created local map. Additionally, to avoid issues with drifting localization, absolute localization is globally corrected at discrete times, according to predefined event criteria, by matching the current local map to the orbiter's global map. The resolutions of local and global maps can be appropriately chosen for computation and accuracy purposes. Further, the online generated local map, of the form of a structured elevation grid map, can also be used to evaluate the traversability of the surrounding environment and allow for continuous navigation. The objective of this study is to support long‐range low‐supervision planetary exploration. The implemented SLAM technique has been validated with a data set acquired during a field test campaign performed at the Teide Volcano on the island of Tenerife, representative of a Mars/Moon exploration scenario.@article{etsardouEsa2020,author={D. Geromichalos and M.Azkarate and E. Tsardoulias and L. Gerdes and L. Petrou and C. Perez Del Pulgar},title={SLAM for Autonomous Planetary Rovers with Global Localization},journal={Journal of Field Robotics},pages={1-18},year={2020},month={02},date={2020-02-28},url={https://onlinelibrary.wiley.com/doi/abs/10.1002/rob.21943},doi={https://doi.org/10.1002/rob.21943},publisher's url={https://onlinelibrary.wiley.com/journal/15564967},keywords={autonomous navigation;long term localization;planetary rovers;SLAM},abstract={This paper describes a novel approach to simultaneous localization and mapping (SLAM) techniques applied to the autonomous planetary rover exploration scenario to reduce both the relative and absolute localization errors, using two well‐proven techniques: particle filters and scan matching. Continuous relative localization is improved by matching high‐resolution sensor scans to the online created local map. Additionally, to avoid issues with drifting localization, absolute localization is globally corrected at discrete times, according to predefined event criteria, by matching the current local map to the orbiter\'s global map. The resolutions of local and global maps can be appropriately chosen for computation and accuracy purposes. Further, the online generated local map, of the form of a structured elevation grid map, can also be used to evaluate the traversability of the surrounding environment and allow for continuous navigation. The objective of this study is to support long‐range low‐supervision planetary exploration. The implemented SLAM technique has been validated with a data set acquired during a field test campaign performed at the Teide Volcano on the island of Tenerife, representative of a Mars/Moon exploration scenario.}} A. Tzitzis, S. Megalou, S. Siachalou, E. Tsardoulias, A. Filotheou, T. Yioultsis, and A. G. Dimitriou IEEE Journal of Radio Frequency Identification, 2020 Jun In this work, we present a method for 3D localization of RFID tags by a reader-equipped robot with a single antenna. The robot carries a set of sensors, which enable it to create a map of the environment and locate itself in it (Simultaneous Localization and Mapping -SLAM). Then we exploit the collected phase measurements to localize large tag populations in real-time. We show that by forcing the robot to move along non-straight trajectories, thus creating non-linear synthetic apertures, the circular ambiguity of the possible tag’s locations is eliminated and 3D localization is accomplished. A reliability metric is introduced, suitable for real-time assessment of the localization error. We investigate how the curvature of the robot’s trajectory affects the accuracy under varying multipath conditions. It is found that increasing the trajectory’s slope and number of turns improves the accuracy of the method. We introduce a phase model that accounts for the effects of multipath and derive the closed form expression of the resultant’s phase probability density function. Finally, the proposed method is extended when multiple antennas are available. Experimental results in a "multipath-rich" indoor environment demonstrate a mean 3D error of 35cm, achieved in a few seconds.@article{etsardouRfid22020,author={A. Tzitzis and S. Megalou and S. Siachalou and E. Tsardoulias and A. Filotheou and T. Yioultsis and and A. G. Dimitriou},title={Trajectory Planning of a Moving Robot Empowers 3D Localization of RFID Tags with a Single Antenna},journal={IEEE Journal of Radio Frequency Identification},year={2020},month={06},date={2020-06-05},url={https://ieeexplore.ieee.org/document/9109328},doi={https://doi.org/10.1109/JRFID.2020.3000332},publisher's url={https://doi.org/10.1109/JRFID.2020.3000332},keywords={robotics;SLAM;RFID;3D Localization;Non Linear Optimization;Phase Unwrapping;Trajectory Evaluation},abstract={In this work, we present a method for 3D localization of RFID tags by a reader-equipped robot with a single antenna. The robot carries a set of sensors, which enable it to create a map of the environment and locate itself in it (Simultaneous Localization and Mapping -SLAM). Then we exploit the collected phase measurements to localize large tag populations in real-time. We show that by forcing the robot to move along non-straight trajectories, thus creating non-linear synthetic apertures, the circular ambiguity of the possible tag’s locations is eliminated and 3D localization is accomplished. A reliability metric is introduced, suitable for real-time assessment of the localization error. We investigate how the curvature of the robot’s trajectory affects the accuracy under varying multipath conditions. It is found that increasing the trajectory’s slope and number of turns improves the accuracy of the method. We introduce a phase model that accounts for the effects of multipath and derive the closed form expression of the resultant’s phase probability density function. Finally, the proposed method is extended when multiple antennas are available. Experimental results in a \"multipath-rich\" indoor environment demonstrate a mean 3D error of 35cm, achieved in a few seconds.}} Michail D. Papamichail and Andreas L. Symeonidis "A Generic Methodology for Early Identification of Non-Maintainable Source Code Components through Analysis of Software Releases" Information and Software Technology, 118, pp. 106218, 2020 Feb Contemporary development approaches consider that time-to-market is of utmost importance and assume that software projects are constantly evolving, driven by the continuously changing requirements of end-users. This practically requires an iterative process where software is changing by introducing new or updating existing software/user features, while at the same time continuing to support the stable ones. In order to ensure efficient software evolution, the need to produce maintainable software is evident. In this work, we argue that non-maintainable software is not the outcome of a single change, but the consequence of a series of changes throughout the development lifecycle. To that end, we define a maintainability evaluation methodology across releases and employ various information residing in software repositories, so as to decide on the maintainability of software. Upon using the dropping of packages as a non-maintainability indicator (accompanied by a series of quality-related criteria), the proposed methodology involves using one-class-classification techniques for evaluating maintainability at a package level, on four different axes each targeting a primary source code property: complexity, cohesion, coupling, and inheritance. Given the qualitative and quantitative evaluation of our methodology, we argue that apart from providing accurate and interpretable maintainability evaluation at package level, we can also identify non-maintainable components at an early stage. This early stage is in many cases around 50% of the software package lifecycle. Based on our findings, we conclude that modeling the trending behavior of certain static analysis metrics enables the effective identification of non-maintainable software components and thus can be a valuable tool for the software engineers.@article{ISTmaintainabilityPaper,author={Michail D. Papamichail and Andreas L. Symeonidis},title={A Generic Methodology for Early Identification of Non-Maintainable Source Code Components through Analysis of Software Releases},journal={Information and Software Technology},volume={118},pages={106218},year={2020},month={02},date={2020-02-01},url={https://issel.ee.auth.gr/wp-content/uploads/2020/06/ISTmaintainabilityPaper.pdf},doi={https://doi.org/10.1016/j.infsof.2019.106218},issn={0950-5849},keywords={static analysis metrics;Software releases;maintainability evaluation;software quality;trend analysis},abstract={Contemporary development approaches consider that time-to-market is of utmost importance and assume that software projects are constantly evolving, driven by the continuously changing requirements of end-users. This practically requires an iterative process where software is changing by introducing new or updating existing software/user features, while at the same time continuing to support the stable ones. In order to ensure efficient software evolution, the need to produce maintainable software is evident. In this work, we argue that non-maintainable software is not the outcome of a single change, but the consequence of a series of changes throughout the development lifecycle. To that end, we define a maintainability evaluation methodology across releases and employ various information residing in software repositories, so as to decide on the maintainability of software. Upon using the dropping of packages as a non-maintainability indicator (accompanied by a series of quality-related criteria), the proposed methodology involves using one-class-classification techniques for evaluating maintainability at a package level, on four different axes each targeting a primary source code property: complexity, cohesion, coupling, and inheritance. Given the qualitative and quantitative evaluation of our methodology, we argue that apart from providing accurate and interpretable maintainability evaluation at package level, we can also identify non-maintainable components at an early stage. This early stage is in many cases around 50% of the software package lifecycle. Based on our findings, we conclude that modeling the trending behavior of certain static analysis metrics enables the effective identification of non-maintainable software components and thus can be a valuable tool for the software engineers.}}

### 2019

#### Journal Articles

 Alexandros Filotheou, Emmanouil Tsardoulias, Antonis Dimitriou, Andreas Symeonidis and Loukas Petrou "Quantitative and Qualitative Evaluation of ROS-Enabled Local and Global Planners in 2D Static Environments" Journal of Intelligent & Robotic Systems, 2019 Oct Apart from perception, one of the most fundamental aspects of an autonomous mobile robot is the ability to adequately and safely traverse the environment it operates in. This ability is called Navigation and is performed in a two- or three-dimensional fashion, except for cases where the robot is neither a ground vehicle nor articulated (e.g. robotics arms). The planning part of navigation comprises a global planner, suitable for generating a path from an initial to a target pose, and a local planner tasked with traversing the aforementioned path while dealing with environmental, sensorial and motion uncertainties. However, the task of selecting the optimal global and/or local planner combination is quite hard since no research provides insight on which is best regarding the domain and planner limitations. In this context, current work performs a comparative analysis on qualitative and quantitative aspects of the most common ROS-enabled global and local planners for robots operating in two-dimensional static environments, on the basis of mission-centered and planner-related metrics, optimality and traversability aspects, as well as non-measurable aspects, such as documentation quality, parameterisability, ease of use, etc.@article{Filotheou2019,author={Alexandros Filotheou and Emmanouil Tsardoulias and Antonis Dimitriou and Andreas Symeonidis and Loukas Petrou},title={Quantitative and Qualitative Evaluation of ROS-Enabled Local and Global Planners in 2D Static Environments},journal={Journal of Intelligent & Robotic Systems},year={2019},month={10},date={2019-10-21},url={https://bit.ly/2yylSu4},doi={http://10.1007/s10846-019-01086-y},issn={1573-0409},abstract={Apart from perception, one of the most fundamental aspects of an autonomous mobile robot is the ability to adequately and safely traverse the environment it operates in. This ability is called Navigation and is performed in a two- or three-dimensional fashion, except for cases where the robot is neither a ground vehicle nor articulated (e.g. robotics arms). The planning part of navigation comprises a global planner, suitable for generating a path from an initial to a target pose, and a local planner tasked with traversing the aforementioned path while dealing with environmental, sensorial and motion uncertainties. However, the task of selecting the optimal global and/or local planner combination is quite hard since no research provides insight on which is best regarding the domain and planner limitations. In this context, current work performs a comparative analysis on qualitative and quantitative aspects of the most common ROS-enabled global and local planners for robots operating in two-dimensional static environments, on the basis of mission-centered and planner-related metrics, optimality and traversability aspects, as well as non-measurable aspects, such as documentation quality, parameterisability, ease of use, etc.}} Emmanouil Krasanakis, Emmanouil Schinas, Symeon Papadopoulos, Yiannis Kompatsiaris and Andreas Symeonidis Information Processing & Management, pp. 102053, 2019 Jun Local community detection is an emerging topic in network analysis that aims to detect well-connected communities encompassing sets of priorly known seed nodes. In this work, we explore the similar problem of ranking network nodes based on their relevance to the communities characterized by seed nodes. However, seed nodes may not be central enough or sufficiently many to produce high quality ranks. To solve this problem, we introduce a methodology we call seed oversampling, which first runs a node ranking algorithm to discover more nodes that belong to the community and then reruns the same ranking algorithm for the new seed nodes. We formally discuss why this process improves the quality of calculated community ranks if the original set of seed nodes is small and introduce a boosting scheme that iteratively repeats seed oversampling to further improve rank quality when certain ranking algorithm properties are met. Finally, we demonstrate the effectiveness of our methods in improving community relevance ranks given only a few random seed nodes of real-world network communities. In our experiments, boosted and simple seed oversampling yielded better rank quality than the previous neighborhood inflation heuristic, which adds the neighborhoods of original seed nodes to seeds.@article{KRASANAKIS2019102053,author={Emmanouil Krasanakis and Emmanouil Schinas and Symeon Papadopoulos and Yiannis Kompatsiaris and Andreas Symeonidis},title={Boosted seed oversampling for local community ranking},journal={Information Processing & Management},pages={102053},year={2019},month={06},date={2019-06-19},doi={https://doi.org/10.1016/j.ipm.2019.06.002},issn={0306-4573},publisher's url={http://www.sciencedirect.com/science/article/pii/S0306457318308574},abstract={Local community detection is an emerging topic in network analysis that aims to detect well-connected communities encompassing sets of priorly known seed nodes. In this work, we explore the similar problem of ranking network nodes based on their relevance to the communities characterized by seed nodes. However, seed nodes may not be central enough or sufficiently many to produce high quality ranks. To solve this problem, we introduce a methodology we call seed oversampling, which first runs a node ranking algorithm to discover more nodes that belong to the community and then reruns the same ranking algorithm for the new seed nodes. We formally discuss why this process improves the quality of calculated community ranks if the original set of seed nodes is small and introduce a boosting scheme that iteratively repeats seed oversampling to further improve rank quality when certain ranking algorithm properties are met. Finally, we demonstrate the effectiveness of our methods in improving community relevance ranks given only a few random seed nodes of real-world network communities. In our experiments, boosted and simple seed oversampling yielded better rank quality than the previous neighborhood inflation heuristic, which adds the neighborhoods of original seed nodes to seeds.}} Michail Papamichail, Kyriakos Chatzidimitriou, Thomas Karanikiotis, Napoleon-Christos Oikonomou, Andreas Symeonidis and Sashi Saripalle "BrainRun: A Behavioral Biometrics Dataset towards Continuous Implicit Authentication" Data, 4, (2), 2019 May The widespread use of smartphones has dictated a new paradigm, where mobile applications are the primary channel for dealing with day-to-day tasks. This paradigm is full of sensitive information, making security of utmost importance. To that end, and given the traditional authentication techniques (passwords and/or unlock patterns) which have become ineffective, several research efforts are targeted towards biometrics security, while more advanced techniques are considering continuous implicit authentication on the basis of behavioral biometrics. However, most studies in this direction are performed “in vitro” resulting in small-scale experimentation. In this context, and in an effort to create a solid information basis upon which continuous authentication models can be built, we employ the real-world application “BrainRun”, a brain-training game aiming at boosting cognitive skills of individuals. BrainRun embeds a gestures capturing tool, so that the different types of gestures that describe the swiping behavior of users are recorded and thus can be modeled. Upon releasing the application at both the “Google Play Store” and “Apple App Store”, we construct a dataset containing gestures and sensors data for more than 2000 different users and devices. The dataset is distributed under the CC0 license and can be found at the EU Zenodo repository.@article{Papamichail2019,author={Michail Papamichail and Kyriakos Chatzidimitriou and Thomas Karanikiotis and Napoleon-Christos Oikonomou and Andreas Symeonidis and Sashi Saripalle},title={BrainRun: A Behavioral Biometrics Dataset towards Continuous Implicit Authentication},journal={Data},volume={4},number={2},year={2019},month={05},date={2019-05-03},url={https://res.mdpi.com/data/data-04-00060/article_deploy/data-04-00060.pdf?filename=&attachment=1},doi={http://10.3390/data4020060},issn={2306-5729},abstract={The widespread use of smartphones has dictated a new paradigm, where mobile applications are the primary channel for dealing with day-to-day tasks. This paradigm is full of sensitive information, making security of utmost importance. To that end, and given the traditional authentication techniques (passwords and/or unlock patterns) which have become ineffective, several research efforts are targeted towards biometrics security, while more advanced techniques are considering continuous implicit authentication on the basis of behavioral biometrics. However, most studies in this direction are performed “in vitro” resulting in small-scale experimentation. In this context, and in an effort to create a solid information basis upon which continuous authentication models can be built, we employ the real-world application “BrainRun”, a brain-training game aiming at boosting cognitive skills of individuals. BrainRun embeds a gestures capturing tool, so that the different types of gestures that describe the swiping behavior of users are recorded and thus can be modeled. Upon releasing the application at both the “Google Play Store” and “Apple App Store”, we construct a dataset containing gestures and sensors data for more than 2000 different users and devices. The dataset is distributed under the CC0 license and can be found at the EU Zenodo repository.}} Michail D. Papamichail, Themistoklis Diamantopoulos and Andreas L. Symeonidis "Software Reusability Dataset based on Static Analysis Metrics and Reuse Rate Information" Data in Brief, 2019 Dec The widely adopted component-based development paradigm considers the reuse of proper software components as a primary criterion for successful software development. As a result, various research efforts are directed towards evaluating the extent to which a software component is reusable. Prior efforts follow expert-based approaches, however the continuously increasing open-source software initiative allows the introduction of data-driven alternatives. In this context we have generated a dataset that harnesses information residing in online code hosting facilities and introduces the actual reuse rate of software components as a measure of their reusability. To do so, we have analyzed the most popular projects included in the maven registry and have computed a large number of static analysis metrics at both class and package levels using SourceMeter tool [2] that quantify six major source code properties: complexity, cohesion, coupling, inheritance, documentation and size. For these projects we additionally computed their reuse rate using our self-developed code search engine, AGORA [5]. The generated dataset contains analysis information regarding more than 24,000 classes and 2,000 packages, and can, thus, be used as the information basis towards the design and development of data-driven reusability evaluation methodologies. The dataset is related to the research article entitled "Measuring the Reusability of Software Components using Static Analysis Metrics and Reuse Rate Information@article{PAPAMICHAIL2019104687,author={Michail D. Papamichail and Themistoklis Diamantopoulos and Andreas L. Symeonidis},title={Software Reusability Dataset based on Static Analysis Metrics and Reuse Rate Information},journal={Data in Brief},year={2019},month={12},date={2019-12-31},url={https://reader.elsevier.com/reader/sd/pii/S235234091931042X?token=9CDEB13940390201A35D26027D763CACB6EE4D49BFA9B920C4D32B348809F1F6A7DE309AA1737161C7E5BF1963BBD952},doi={https://doi.org/10.1016/j.dib.2019.104687},keywords={developer-perceived reusability;code reuse;static analysis metrics;Reusability assessment},abstract={The widely adopted component-based development paradigm considers the reuse of proper software components as a primary criterion for successful software development. As a result, various research efforts are directed towards evaluating the extent to which a software component is reusable. Prior efforts follow expert-based approaches, however the continuously increasing open-source software initiative allows the introduction of data-driven alternatives. In this context we have generated a dataset that harnesses information residing in online code hosting facilities and introduces the actual reuse rate of software components as a measure of their reusability. To do so, we have analyzed the most popular projects included in the maven registry and have computed a large number of static analysis metrics at both class and package levels using SourceMeter tool [2] that quantify six major source code properties: complexity, cohesion, coupling, inheritance, documentation and size. For these projects we additionally computed their reuse rate using our self-developed code search engine, AGORA [5]. The generated dataset contains analysis information regarding more than 24,000 classes and 2,000 packages, and can, thus, be used as the information basis towards the design and development of data-driven reusability evaluation methodologies. The dataset is related to the research article entitled \"Measuring the Reusability of Software Components using Static Analysis Metrics and Reuse Rate Information}} Michail D. Papamichail , Themistoklis Diamantopoulos and Andreas L. Symeonidis Journal of Systems and Software, pp. 110423, 2019 Sep Nowadays, the continuously evolving open-source community and the increasing demands of end users are forming a new software development paradigm; developers rely more on reusing components from online sources to minimize the time and cost of software development. An important challenge in this context is to evaluate the degree to which a software component is suitable for reuse, i.e. its reusability. Contemporary approaches assess reusability using static analysis metrics by relying on the help of experts, who usually set metric thresholds or provide ground truth values so that estimation models are built. However, even when expert help is available, it may still be subjective or case-specific. In this work, we refrain from expert-based solutions and employ the actual reuse rate of source code components as ground truth for building a reusability estimation model. We initially build a benchmark dataset, harnessing the power of online repositories to determine the number of reuse occurrences for each component in the dataset. Subsequently, we build a model based on static analysis metrics to assess reusability from five different properties: complexity, cohesion, coupling, inheritance, documentation and size. The evaluation of our methodology indicates that our system can effectively assess reusability as perceived by developers.@article{PAPAMICHAIL2019110423,author={Michail D. Papamichail and Themistoklis Diamantopoulos and Andreas L. Symeonidis},title={Measuring the Reusability of Software Components using Static Analysis Metrics and Reuse Rate Information},journal={Journal of Systems and Software},pages={110423},year={2019},month={09},date={2019-09-17},url={https://issel.ee.auth.gr/wp-content/uploads/2019/09/2019mpapamicJSS.pdf},doi={https://doi.org/10.1016/j.jss.2019.110423},issn={0164-1212},publisher's url={https://www.sciencedirect.com/science/article/pii/S0164121219301979},keywords={developer-perceived reusability;code reuse;static analysis metrics;reusability estimation},abstract={Nowadays, the continuously evolving open-source community and the increasing demands of end users are forming a new software development paradigm; developers rely more on reusing components from online sources to minimize the time and cost of software development. An important challenge in this context is to evaluate the degree to which a software component is suitable for reuse, i.e. its reusability. Contemporary approaches assess reusability using static analysis metrics by relying on the help of experts, who usually set metric thresholds or provide ground truth values so that estimation models are built. However, even when expert help is available, it may still be subjective or case-specific. In this work, we refrain from expert-based solutions and employ the actual reuse rate of source code components as ground truth for building a reusability estimation model. We initially build a benchmark dataset, harnessing the power of online repositories to determine the number of reuse occurrences for each component in the dataset. Subsequently, we build a model based on static analysis metrics to assess reusability from five different properties: complexity, cohesion, coupling, inheritance, documentation and size. The evaluation of our methodology indicates that our system can effectively assess reusability as perceived by developers.}} Eleni Poptsi, Emmanouil Tsardoulias, Despina Moraitou, Andreas Symeonidis and Magda Tsolaki Journal of Alzheimer's Disease, pp. 1-19, 2019 Oct Background:Subjective cognitive decline (SCD) and mild cognitive impairment (MCI) are acknowledged stages of the clinical spectrum of Alzheimer’s disease (AD), and cognitive control seems to be among the first neuropsychological predictors of cognitive decline. Existing tests are usually affected by educational level, linguistic abilities, cultural differences, and social status, constituting them error-prone when differentiating between the aforementioned stages. Creating robust neuropsychological tests is therefore prominent. Objective:The design of a novel psychometric battery for the cognitive control and attention assessment, free of demographic effects, capable to discriminate cognitively healthy aging, SCD, MCI, and mild Dementia (mD). Methods:The battery initial hypothesis was tuned using iterations of administration on random sampling healthy older adults and people with SCD, MCI, and mD, from the area of Thessaloniki, Greece. This resulted in the first release of the REflexes MEasurement DEviceS for Alzheimer battery (REMEDES for Alzheimer-R4Alz). Results:The first release lasts for almost an hour. The battery was design to assess working memory (WM) including WM storage, processing, and updating, enriched by episodic buffer recruitment. It was also designed to assess attention control abilities comprising selective, sustained, and divided attention subtasks. Finally, it comprises an inhibitory control, a task/rule switching or set-shifting, and a cognitive flexibility subtask as a combination of inhibition and task/rule switching abilities. Conclusion:The R4Alz battery is an easy to use psychometric battery with increasing difficulty levels and assumingly ecological validity, being entertaining for older adults, potentially free of demographic effects, and promising as a more accurate and early diagnosis tool of neurodegeneration.@article{poptsi2019remedes,author={Eleni Poptsi and Emmanouil Tsardoulias and Despina Moraitou and Andreas Symeonidis and Magda Tsolaki},title={REMEDES for Alzheimer-R4Alz Battery: Design and Development of a New Tool of Cognitive Control Assessment for the Diagnosis of Minor and Major Neurocognitive Disorders},journal={Journal of Alzheimer's Disease},pages={1-19},year={2019},month={10},date={2019-10-18},doi={http://10.3233/JAD-190798},publisher's url={https://content.iospress.com/},abstract={Background:Subjective cognitive decline (SCD) and mild cognitive impairment (MCI) are acknowledged stages of the clinical spectrum of Alzheimer’s disease (AD), and cognitive control seems to be among the first neuropsychological predictors of cognitive decline. Existing tests are usually affected by educational level, linguistic abilities, cultural differences, and social status, constituting them error-prone when differentiating between the aforementioned stages. Creating robust neuropsychological tests is therefore prominent. Objective:The design of a novel psychometric battery for the cognitive control and attention assessment, free of demographic effects, capable to discriminate cognitively healthy aging, SCD, MCI, and mild Dementia (mD). Methods:The battery initial hypothesis was tuned using iterations of administration on random sampling healthy older adults and people with SCD, MCI, and mD, from the area of Thessaloniki, Greece. This resulted in the first release of the REflexes MEasurement DEviceS for Alzheimer battery (REMEDES for Alzheimer-R4Alz). Results:The first release lasts for almost an hour. The battery was design to assess working memory (WM) including WM storage, processing, and updating, enriched by episodic buffer recruitment. It was also designed to assess attention control abilities comprising selective, sustained, and divided attention subtasks. Finally, it comprises an inhibitory control, a task/rule switching or set-shifting, and a cognitive flexibility subtask as a combination of inhibition and task/rule switching abilities. Conclusion:The R4Alz battery is an easy to use psychometric battery with increasing difficulty levels and assumingly ecological validity, being entertaining for older adults, potentially free of demographic effects, and promising as a more accurate and early diagnosis tool of neurodegeneration.}} Emmanouil G. Tsardoulias, M. Protopapas, Andreas L. Symeonidis and Loukas Petrou Journal of Intelligent & Robotic Systems, 2019 Jul The alignment of two occupancy grid maps generated by SLAM algorithms is a quite researched problem, being an obligatory step either for unsupervised map merging techniques or for evaluation of OGMs (Occupancy Grid Maps) against a blueprint of the environment. This paper provides an overview of the existing automatic alignment techniques of two occupancy grid maps that employ pattern matching. Additionally, an alignment pipeline using local features and image descriptors is implemented, as well as a method to eliminate erroneous correspondences, aiming at producing the correct transformation between the two maps. Finally, map quality metrics are proposed and utilized, in order to quantify the produced map’s correctness. A comparative analysis was performed over a number of image processing and OGM-oriented detectors and descriptors, in order to identify the best combinations for the map evaluation problem, performed between two OGMs or between an OGM and a Blueprint map.@article{Tsardoulias2019,author={Emmanouil G. Tsardoulias and M. Protopapas and Andreas L. Symeonidis and Loukas Petrou},title={A Comparative Analysis of Pattern Matching Techniques Towards OGM Evaluation},journal={Journal of Intelligent & Robotic Systems},year={2019},month={07},date={2019-07-11},url={https://link.springer.com/content/pdf/10.1007%2Fs10846-019-01053-7.pdf},doi={http://10.1007/s10846-019-01053-7},issn={1573-0409},publisher's url={https://link.springer.com/content/pdf/10.1007%2Fs10846-019-01053-7.pdf},abstract={The alignment of two occupancy grid maps generated by SLAM algorithms is a quite researched problem, being an obligatory step either for unsupervised map merging techniques or for evaluation of OGMs (Occupancy Grid Maps) against a blueprint of the environment. This paper provides an overview of the existing automatic alignment techniques of two occupancy grid maps that employ pattern matching. Additionally, an alignment pipeline using local features and image descriptors is implemented, as well as a method to eliminate erroneous correspondences, aiming at producing the correct transformation between the two maps. Finally, map quality metrics are proposed and utilized, in order to quantify the produced map’s correctness. A comparative analysis was performed over a number of image processing and OGM-oriented detectors and descriptors, in order to identify the best combinations for the map evaluation problem, performed between two OGMs or between an OGM and a Blueprint map.}} Anastasios Tzitzis, Spyros Megalou, Stavroula Siachalou, Emmanouil Tsardoulias, Athanasios Kehagias, Traianos Yioultsis and Antonis Dimitriou "Localization of RFID Tags by a Moving Robot, via Phase Unwrapping and Non-Linear Optimization" IEEE Journal of Radio Frequency Identification, 3, (4), pp. 216 - 226, 2019 Aug In this paper, we propose a new method for the localization of RFID tags, by deploying off-the-shelf RFID equipment on a robotic platform. The constructed robot is capable to perform Simultaneous Localization (of its own position) and Mapping (SLAM) of the environment and then locate the RFID tags around its path. The proposed method is based on properly treating the measured phase of the backscattered signal by each tag at the reader’s antenna, located on top of the robot. More specifically, the measured phase samples are reconstructed, such that the $2\pi$ discontinuities are eliminated (phase-unwrapping). This allows for the formation of an optimization problem, which can be solved rapidly by standard methods. The proposed method is experimentally compared against the SAR/imaging methods, which represent the accuracy benchmark in prior-art, deploying off-the-shelf equipment. It is shown that the proposed method solves exactly the same problem as holographic-imaging methods, overcoming the grid-density constraints of the latter. Furthermore, the problem, being calculations-grid-independent, is solved orders of magnitude faster, allowing for the applicability of the method in real-time inventorying and localization. It is also shown that the state-of-the-art SLAM method, which is used for the estimation of the trace of the robot, also suffers from errors, which directly affect the accuracy of the RFID localization method. Deployment of reference RFID tags at known positions, seems to significantly reduce such errors.@article{tzitzis2019localization,author={Anastasios Tzitzis and Spyros Megalou and Stavroula Siachalou and Emmanouil Tsardoulias and Athanasios Kehagias and Traianos Yioultsis and Antonis Dimitriou},title={Localization of RFID Tags by a Moving Robot, via Phase Unwrapping and Non-Linear Optimization},journal={IEEE Journal of Radio Frequency Identification},volume={3},number={4},pages={216 - 226},year={2019},month={08},date={2019-08-26},url={https://bit.ly/2KYVgbq},doi={https://doi.org/10.1109/JRFID.2019.2936969},abstract={In this paper, we propose a new method for the localization of RFID tags, by deploying off-the-shelf RFID equipment on a robotic platform. The constructed robot is capable to perform Simultaneous Localization (of its own position) and Mapping (SLAM) of the environment and then locate the RFID tags around its path. The proposed method is based on properly treating the measured phase of the backscattered signal by each tag at the reader’s antenna, located on top of the robot. More specifically, the measured phase samples are reconstructed, such that the $2\\pi$ discontinuities are eliminated (phase-unwrapping). This allows for the formation of an optimization problem, which can be solved rapidly by standard methods. The proposed method is experimentally compared against the SAR/imaging methods, which represent the accuracy benchmark in prior-art, deploying off-the-shelf equipment. It is shown that the proposed method solves exactly the same problem as holographic-imaging methods, overcoming the grid-density constraints of the latter. Furthermore, the problem, being calculations-grid-independent, is solved orders of magnitude faster, allowing for the applicability of the method in real-time inventorying and localization. It is also shown that the state-of-the-art SLAM method, which is used for the estimation of the trace of the robot, also suffers from errors, which directly affect the accuracy of the RFID localization method. Deployment of reference RFID tags at known positions, seems to significantly reduce such errors.}}

### 2015

#### Inproceedings Papers

 Themistoklis Diamantopoulos and Andreas Symeonidis "Towards Interpretable Defect-Prone Component Analysis using Genetic Fuzzy Systems" IEEE/ACM 4th International Workshop on Realizing Artificial Intelligence Synergies in Software Engineering (RAISE, pp. 32-38, Florence, Italy, 2015 May The problem of Software Reliability Prediction is attracting the attention of several researchers during the last few years. Various classification techniques are proposed in current literature which involve the use of metrics drawn from version control systems in order to classify software components as defect-prone or defect-free. In this paper, we create a novel genetic fuzzy rule-based system to efficiently model the defect-proneness of each component. The system uses a Mamdani-Assilian inference engine and models the problem as a one-class classification task. System rules are constructed using a genetic algorithm, where each chromosome represents a rule base (Pittsburgh approach). The parameters of our fuzzy system and the operators of the genetic algorithm are designed with regard to producing interpretable output. Thus, the output offers not only effective classification, but also a comprehensive set of rules that can be easily visualized to extract useful conclusions about the metrics of the software.@inproceedings{2015DiamantopoulosRAISE,author={Themistoklis Diamantopoulos and Andreas Symeonidis},title={Towards Interpretable Defect-Prone Component Analysis using Genetic Fuzzy Systems},booktitle={IEEE/ACM 4th International Workshop on Realizing Artificial Intelligence Synergies in Software Engineering (RAISE},pages={32-38},address={Florence, Italy},year={2015},month={05},date={2015-05-01},url={http://issel.ee.auth.gr/wp-content/uploads/2017/01/Towards-Interpretable-Defect-Prone-Component-Analysis-using-Genetic-Fuzzy-Systems-.pdf},keywords={Load Forecasting},abstract={The problem of Software Reliability Prediction is attracting the attention of several researchers during the last few years. Various classification techniques are proposed in current literature which involve the use of metrics drawn from version control systems in order to classify software components as defect-prone or defect-free. In this paper, we create a novel genetic fuzzy rule-based system to efficiently model the defect-proneness of each component. The system uses a Mamdani-Assilian inference engine and models the problem as a one-class classification task. System rules are constructed using a genetic algorithm, where each chromosome represents a rule base (Pittsburgh approach). The parameters of our fuzzy system and the operators of the genetic algorithm are designed with regard to producing interpretable output. Thus, the output offers not only effective classification, but also a comprehensive set of rules that can be easily visualized to extract useful conclusions about the metrics of the software.}}

### 2014

#### Conference Papers

 Fotis Psomopoulos, Emmanouil Tsardoulias, Alexandros Giokas, Cezary Zielinski, Vincent Prunet, Ilias Trochidis, David Daney, Manuel Serrano, Ludovic Courtes, Stratos Arampatzis and Pericles A. Mitkas "RAPP System Architecture, Assistance and Service Robotics in a Human Environment" International Conference on Intelligent Robots and Systems (IEEE/RSJ), Chicago, Illinois, 2014 Sep Robots are fast becoming a part of everyday life. This rise can be evidenced both through the public news and announcements, as well as in recent literature in the robotics scientific communities. This expanding development requires new paradigms in producing the necessary software to allow for the users@conference{2014PsomopoulosIEEE/RSJ,author={Fotis Psomopoulos and Emmanouil Tsardoulias and Alexandros Giokas and Cezary Zielinski and Vincent Prunet and Ilias Trochidis and David Daney and Manuel Serrano and Ludovic Courtes and Stratos Arampatzis and Pericles A. Mitkas},title={RAPP System Architecture, Assistance and Service Robotics in a Human Environment},booktitle={International Conference on Intelligent Robots and Systems (IEEE/RSJ)},address={Chicago, Illinois},year={2014},month={09},date={2014-09-14},url={http://issel.ee.auth.gr/wp-content/uploads/2016/02/RAPP-System-Architecture-Assistance-and-Service-Robotics-in-a-Human-Environment.pdf},keywords={Load Forecasting},abstract={Robots are fast becoming a part of everyday life. This rise can be evidenced both through the public news and announcements, as well as in recent literature in the robotics scientific communities. This expanding development requires new paradigms in producing the necessary software to allow for the users}}

### 2013

#### Conference Papers

 Tsardoulias, E. G., A. Iliakopoulou, A. Kargakos, and L. Petrou "On Global Path Planning for Occupancy Grid Maps" 22nd International Workshop on Robotics in Alpe-Adria-Danube Region, 2013 Sep This paper considers the problem of robot path planning in indoors environments. Several approaches to tackle this problem have been proposed, which employ structures such as graphs or trees to direct robot’s movement throughout space. The current document constitutes a survey of eight well-known path planning methods, aiming at comparing and evaluating their performances in various environments of different characteristics.@conference{etsardouRaad2013,author={Tsardoulias and E. G. and A. Iliakopoulou and A. Kargakos and and L. Petrou},title={On Global Path Planning for Occupancy Grid Maps},booktitle={22nd International Workshop on Robotics in Alpe-Adria-Danube Region},year={2013},month={09},date={2013-09-11},url={https://bit.ly/2ZunqRJ},keywords={Robot Path Planning;Visibility Graphs;RRTs;PRMs;Dijkstra’s algorithm},abstract={This paper considers the problem of robot path planning in indoors environments. Several approaches to tackle this problem have been proposed, which employ structures such as graphs or trees to direct robot’s movement throughout space. The current document constitutes a survey of eight well-known path planning methods, aiming at comparing and evaluating their performances in various environments of different characteristics.}}

### 2012

#### Inbooks

 Kiriakos C. Chatzidimitriou, Ioannis Partalas, Pericles A. Mitkas and Ioannis Vlahavas "Transferring Evolved Reservoir Features in Reinforcement Learning Tasks" Charpter:1, 7188, pp. 213-224, Springer Berlin Heidelberg, 2012 Jan Lecture Notes in Artificial Intelligent (LNAI)@inbook{2012ChatzidimitriouLNAI,author={Kiriakos C. Chatzidimitriou and Ioannis Partalas and Pericles A. Mitkas and Ioannis Vlahavas},title={Transferring Evolved Reservoir Features in Reinforcement Learning Tasks},chapter={1},volume={7188},pages={213-224},publisher={Springer Berlin Heidelberg},year={2012},month={01},date={2012-01-01},url={http://issel.ee.auth.gr/wp-content/uploads/2017/01/Transferring-Evolved-Reservoir-Features-in-Reinforcement-Learning-Tasks.pdf},doi={http://issel.ee.auth.gr/wp-content/uploads/publications/chp_LNAI.pdf},abstract={Lecture Notes in Artificial Intelligent (LNAI)}} Andreas L. Symeonidis, Panagiotis Toulis and Pericles A. Mitkas "Supporting Agent-Oriented Software Engineering for Data Mining Enhanced Agent Development" Charpter:1, 7607, pp. 7-21, Springer Berlin Heidelberg, 2012 Jun Lecture Notes in Computer Science@inbook{2012SymeonidisLNCS,author={Andreas L. Symeonidis and Panagiotis Toulis and Pericles A. Mitkas},title={Supporting Agent-Oriented Software Engineering for Data Mining Enhanced Agent Development},chapter={1},volume={7607},pages={7-21},publisher={Springer Berlin Heidelberg},year={2012},month={06},date={2012-06-04},url={http://issel.ee.auth.gr/wp-content/uploads/2017/01/Supporting-Agent-Oriented-Software-Engineering-for-Data-Mining-Enhanced-Agent-Development-1.pdf},abstract={Lecture Notes in Computer Science}}

### 2011

#### Conference Papers

 Michalis Tsapanos, Kyriakos C. Chatzidimitriou and Pericles A. Mitkas "A Zeroth-Level Classifier System for Real Time Strategy Games" Web Intelligence and Intelligent Agent Technology (WI-IAT), 2011 IEEE/WIC/ACM International Conference, pp. 244-247, Springer Berlin Heidelberg, Lyons, France, 2011 Aug Real Time Strategy games (RTS) provide an interesting test bed for agents that use Reinforcement Learning (RL) algorithms. From an agent@conference{2011TsapanosWI-IAT,author={Michalis Tsapanos and Kyriakos C. Chatzidimitriou and Pericles A. Mitkas},title={A Zeroth-Level Classifier System for Real Time Strategy Games},booktitle={Web Intelligence and Intelligent Agent Technology (WI-IAT), 2011 IEEE/WIC/ACM International Conference},pages={244-247},publisher={Springer Berlin Heidelberg},address={Lyons, France},year={2011},month={08},date={2011-08-22},url={http://issel.ee.auth.gr/wp-content/uploads/2017/01/A_Zeroth-Level_Classifier_System_for_Real_Time_Str.pdf},keywords={Learning Classifier Systems;Real Time Strategy Games},abstract={Real Time Strategy games (RTS) provide an interesting test bed for agents that use Reinforcement Learning (RL) algorithms. From an agent}}

### 2010

#### Conference Papers

 Fotis E. Psomopoulos and Pericles A. Mitkas "Multi Level Clustering of Phylogenetic Profiles" BioInformatics and BioEngineering (BIBE), 2010 IEEE International Conference, pp. 308-309, Freiburg, Germany, 2010 May The prediction of gene function from genome sequences is one of the main issues in Bioinformatics. Most computational approaches are based on the similarity between sequences to infer gene function. However, the availability of several fully sequenced genomes has enabled alternative approaches, such as phylogenetic profiles. Phylogenetic profiles are vectors which indicate the presence or absence of a gene in other genomes. The main concept of phylogenetic profiles is that proteins participating in a common structural complex or metabolic pathway are likely to evolve in a correlated fashion. In this paper, a multi level clustering algorithm of phylogenetic profiles is presented, which aims to detect inter- and intra-genome gene clusters.@conference{2010PsomopoulosBIBE,author={Fotis E. Psomopoulos and Pericles A. Mitkas},title={Multi Level Clustering of Phylogenetic Profiles},booktitle={BioInformatics and BioEngineering (BIBE), 2010 IEEE International Conference},pages={308-309},address={Freiburg, Germany},year={2010},month={05},date={2010-05-31},url={http://issel.ee.auth.gr/wp-content/uploads/2016/02/Multi-Level-Clustering-of-Phylogenetic-Profiles.pdf},keywords={Algorithm;Clustering;Phylogenetic profiles},abstract={The prediction of gene function from genome sequences is one of the main issues in Bioinformatics. Most computational approaches are based on the similarity between sequences to infer gene function. However, the availability of several fully sequenced genomes has enabled alternative approaches, such as phylogenetic profiles. Phylogenetic profiles are vectors which indicate the presence or absence of a gene in other genomes. The main concept of phylogenetic profiles is that proteins participating in a common structural complex or metabolic pathway are likely to evolve in a correlated fashion. In this paper, a multi level clustering algorithm of phylogenetic profiles is presented, which aims to detect inter- and intra-genome gene clusters.}}

### 2009

#### Books

 Fotis Psomopoulos and Pericles Mitkas "Handbook of Research on Computational Grid Technologies for Life Sciences, Biomedicine, and Healthcare" 2, UK: IGI Global., Catanzaro, Italy, 2009 May @book{2009PsomopoulosHRCGTLSBH,author={Fotis Psomopoulos and Pericles Mitkas},title={Handbook of Research on Computational Grid Technologies for Life Sciences, Biomedicine, and Healthcare},volume={2},publisher={UK: IGI Global.},address={Catanzaro, Italy},year={2009},month={05},date={2009-05-00}}

### 2008

#### Conference Papers

 Pericles A. Mitkas, Vassilis Koutkias, Andreas Symeonidis, Manolis Falelakis, Christos Diou, Irini Lekka, Anastasios T. Delopoulos, Theodoros Agorastos and Nicos Maglaveras "Association Studies on Cervical Cancer Facilitated by Inference and Semantic Technologes: The ASSIST Approach" MIE, Goteborg, Sweden, 2008 May Cervical cancer (CxCa) is currently the second leading cause of cancer-related deaths, for women between 20 and 39 years old. As infection by the human papillomavirus (HPV) is considered as the central risk factor for CxCa, current research focuses on the role of specific genetic and environmental factors in determining HPV persistence and subsequent progression of the disease. ASSIST is an EU-funded research project that aims to facilitate the design and execution of genetic association studies on CxCa in a systematic way by adopting inference and semantic technologies. Toward this goal, ASSIST provides the means for seamless integration and virtual unification of distributed and heterogeneous CxCa data repositories, and the underlying mechanisms to undertake the entire process of expressing and statistically evaluating medical hypotheses based on the collected data in order to generate medically important associations. The ultimate goal for ASSIST is to foster the biomedical research community by providing an open, integrated and collaborative framework to facilitate genetic association studies.@conference{2008MitkasMIE,author={Pericles A. Mitkas and Vassilis Koutkias and Andreas Symeonidis and Manolis Falelakis and Christos Diou and Irini Lekka and Anastasios T. Delopoulos and Theodoros Agorastos and Nicos Maglaveras},title={Association Studies on Cervical Cancer Facilitated by Inference and Semantic Technologes: The ASSIST Approach},booktitle={MIE},address={Goteborg, Sweden},year={2008},month={05},date={2008-05-25},url={http://issel.ee.auth.gr/wp-content/uploads/2016/02/Association-Studies-on-Cervical-Cancer-Facilitated-by-Inference-and-Semantic-Technologies-The-ASSIST-Approach-.pdf},keywords={agent performance evaluation;Supply Chain Management systems},abstract={Cervical cancer (CxCa) is currently the second leading cause of cancer-related deaths, for women between 20 and 39 years old. As infection by the human papillomavirus (HPV) is considered as the central risk factor for CxCa, current research focuses on the role of specific genetic and environmental factors in determining HPV persistence and subsequent progression of the disease. ASSIST is an EU-funded research project that aims to facilitate the design and execution of genetic association studies on CxCa in a systematic way by adopting inference and semantic technologies. Toward this goal, ASSIST provides the means for seamless integration and virtual unification of distributed and heterogeneous CxCa data repositories, and the underlying mechanisms to undertake the entire process of expressing and statistically evaluating medical hypotheses based on the collected data in order to generate medically important associations. The ultimate goal for ASSIST is to foster the biomedical research community by providing an open, integrated and collaborative framework to facilitate genetic association studies.}}

### 2005

#### Books

 Andreas Symeonidis and Pericles A. Mitkas "Agent Intelligence Through Data Mining (Multiagent Systems, Artificial Societies, and Simulated Organizations)" Springer-Verlag New York, Inc., Secaucus, NJ, USA, 2005 Jul @book{2005Symeonidis,author={Andreas Symeonidis and Pericles A. Mitkas},title={Agent Intelligence Through Data Mining (Multiagent Systems, Artificial Societies, and Simulated Organizations)},publisher={Springer-Verlag New York, Inc.},address={Secaucus, NJ, USA},year={2005},month={07},date={2005-07-15}}