Vasileios Kokkinos
Short CV: Dr. Vasileios Kokkinos was born in Ioannina, Greece in 1981. He obtained his diploma from the Physics Department of the University of Patras on October 2003. Next, he was accepted in the postgraduate program “Electronics and Information Processing” in the same department and on March 2006 he obtained his Master Degree. In 2010 he received his PhD on Power Control in Mobile Telecommunication Networks from the Computer Engineering and Informatics Department. He currently works as Computer and Informatics Engineer and Manager at the Distributed Systems and Telematics Lab of the Computer Engineering and Informatics Department. His research interests include data networks, 3rd/4th/5th generation mobile telecommunications networks, multicast routing and group management, radio resource management and internet of things. He has published several research papers in various well-known refereed conferences and articles in scientific journals.
Journal Articles
Bouras, Christos; Stergiou, Eirini; Karakostaki, Charitini; Tzanos, Vasileios; Kokkinos, Vasileios
The Nexus between Wind Energy, Biodiversity Protection and Social Acceptance: Evidence of Good Practices from Greece, Latvia and Poland Journal Article
In: International Journal of Environmental and Ecological Engineering , World Academy of Science, Engineering and Technology, vol. 18, pp. 85-94, 2024.
Abstract | Links | BibTeX | Tags:
@article{4672,
title = {The Nexus between Wind Energy, Biodiversity Protection and Social Acceptance: Evidence of Good Practices from Greece, Latvia and Poland},
author = {Christos Bouras and Eirini Stergiou and Charitini Karakostaki and Vasileios Tzanos and Vasileios Kokkinos},
url = {https://telematics3.upatras.gr/wp-content/uploads/2024/06/IJEEE2023_Bouras.pdf},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {International Journal of Environmental and Ecological Engineering , World Academy of Science, Engineering and Technology},
volume = {18},
pages = {85-94},
abstract = {Wind power represents a major pathway to curtailing greenhouse gas emissions and thus reducing the rate of climate change. A wind turbine runs practically emission-free for 20 years, representing one of the most environmentally sustainable sources of energy. Nevertheless, environmental and biodiversity concerns can often slow down or halt the deployment of wind farms due to local public opposition. This opposition is often fuelled by poor relationships between wind energy stakeholders and civil society, which in many cases led to conflictual protests and property damage. In this context, addressing these concerns is essential in order to facilitate the proliferation of wind farms in Europe and the phase-out of fossil fuels from the energy mix. The aim of this study is to identify a number of good practices and cases to avoid increasing biodiversity protection at all stages of wind farms’ lifecycle in three participating countries, namely Greece, Latvia, and Poland. The results indicate that although available technological solutions are already being exploited worldwide, in these countries, there is still room for improvement. To address this gap, a set of policy recommendations is proposed to accomplish the wind energy targets in the near future while simultaneously mitigating the pertinent biodiversity risks.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Wind power represents a major pathway to curtailing greenhouse gas emissions and thus reducing the rate of climate change. A wind turbine runs practically emission-free for 20 years, representing one of the most environmentally sustainable sources of energy. Nevertheless, environmental and biodiversity concerns can often slow down or halt the deployment of wind farms due to local public opposition. This opposition is often fuelled by poor relationships between wind energy stakeholders and civil society, which in many cases led to conflictual protests and property damage. In this context, addressing these concerns is essential in order to facilitate the proliferation of wind farms in Europe and the phase-out of fossil fuels from the energy mix. The aim of this study is to identify a number of good practices and cases to avoid increasing biodiversity protection at all stages of wind farms’ lifecycle in three participating countries, namely Greece, Latvia, and Poland. The results indicate that although available technological solutions are already being exploited worldwide, in these countries, there is still room for improvement. To address this gap, a set of policy recommendations is proposed to accomplish the wind energy targets in the near future while simultaneously mitigating the pertinent biodiversity risks.
Stefas, Dimitris; Gyftokostas, Nikolaos; Kourelias, Panagiotis; Nanou, Eleni; Tananaki, Chrysoula; Kanelis, Dimitrios; Liolios, Vasileios; Kokkinos, Vasileios; Bouras, Christos; Couris, Stelios
Honey discrimination based on the bee feeding by Laser Induced Breakdown Spectroscopy Journal Article
In: Food Control, Elsevier Science, pp. 1 - 9 , 2022.
Abstract | Links | BibTeX | Tags:
@article{4568,
title = {Honey discrimination based on the bee feeding by Laser Induced Breakdown Spectroscopy},
author = {Dimitris Stefas and Nikolaos Gyftokostas and Panagiotis Kourelias and Eleni Nanou and Chrysoula Tananaki and Dimitrios Kanelis and Vasileios Liolios and Vasileios Kokkinos and Christos Bouras and Stelios Couris},
url = {https://telematics3.upatras.gr/honey-discrimination-based-on-the-bee-feeding-by-libs/},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Food Control, Elsevier Science},
pages = {1 - 9 },
abstract = {In the present work, the effects of artificial feeding of bees on the honey are investigated by employing for the first time, Laser Induced Breakdown Spectroscopy (LIBS) by analyzing the emission spectral characteristics of the plasma created on the surface of honey samples. Correlation plots indicating the importance of spectral lines of elements as e.g., Calcium (Ca), Magnesium (Mg), Sodium (Na) and Potassium (K) are constructed, while machine learning algorithms based on Linear Discriminant Analysis (LDA) and Random Forest Classifiers (RFC) are employed to classify the honey samples in terms of the bee food used. The constructed machine learning
models were validated by both cross-validation and external validation, while the obtained accuracies exceeded 90% of correct classification, indicating the potential of LIBS technique for honey discrimination. The obtained results by LIBS were also validated by HPLC-RID, which is the standard technique used for the analysis of the main honey sugars.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In the present work, the effects of artificial feeding of bees on the honey are investigated by employing for the first time, Laser Induced Breakdown Spectroscopy (LIBS) by analyzing the emission spectral characteristics of the plasma created on the surface of honey samples. Correlation plots indicating the importance of spectral lines of elements as e.g., Calcium (Ca), Magnesium (Mg), Sodium (Na) and Potassium (K) are constructed, while machine learning algorithms based on Linear Discriminant Analysis (LDA) and Random Forest Classifiers (RFC) are employed to classify the honey samples in terms of the bee food used. The constructed machine learning
models were validated by both cross-validation and external validation, while the obtained accuracies exceeded 90% of correct classification, indicating the potential of LIBS technique for honey discrimination. The obtained results by LIBS were also validated by HPLC-RID, which is the standard technique used for the analysis of the main honey sugars.
models were validated by both cross-validation and external validation, while the obtained accuracies exceeded 90% of correct classification, indicating the potential of LIBS technique for honey discrimination. The obtained results by LIBS were also validated by HPLC-RID, which is the standard technique used for the analysis of the main honey sugars.
Stefas, Dimitrios; Gyftokostas, Nikolaos; Kourelias, Panagiotis; Nanou, Eleni; Kokkinos, Vasileios; Bouras, Christos; Couris, Stelios
A Laser-Based Method for the Detection of Honey Adulteration Journal Article
In: Applied Sciences, MPDI, Special Issue Chemical Composition, Properties and Applications of Honey, pp. 1 - 14 , 2021.
Abstract | Links | BibTeX | Tags:
@article{4546,
title = {A Laser-Based Method for the Detection of Honey Adulteration},
author = {Dimitrios Stefas and Nikolaos Gyftokostas and Panagiotis Kourelias and Eleni Nanou and Vasileios Kokkinos and Christos Bouras and Stelios Couris},
url = {https://telematics3.upatras.gr/applsci-11-06435/},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Applied Sciences, MPDI, Special Issue Chemical Composition, Properties and Applications of Honey},
pages = {1 - 14 },
abstract = {In the present work, laser-induced breakdown spectroscopy, aided by some machine learning algorithms (i.e., linear discriminant analysis (LDA) and extremely randomized trees (ERT)), is used for the detection of honey adulteration with glucose syrup. In addition, it is shown that instead of the entire LIBS spectrum, the spectral lines of inorganic ingredients of honey (i.e., calcium, sodium, and potassium) can be also used for the detection of adulteration providing efficient discrimination. The constructed predictive models attained high classification accuracies exceeding 90% correct classification.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In the present work, laser-induced breakdown spectroscopy, aided by some machine learning algorithms (i.e., linear discriminant analysis (LDA) and extremely randomized trees (ERT)), is used for the detection of honey adulteration with glucose syrup. In addition, it is shown that instead of the entire LIBS spectrum, the spectral lines of inorganic ingredients of honey (i.e., calcium, sodium, and potassium) can be also used for the detection of adulteration providing efficient discrimination. The constructed predictive models attained high classification accuracies exceeding 90% correct classification.
Gyftokostas, Nikolaos; Nanou, Eleni; Stefas, Dimitrios; Kokkinos, Vasileios; Bouras, Christos; Couris, Stelios
In: Open Access Journal, MDPI, Special Issue Characterization of Olive Products from Greece, vol. 26, pp. 1 - 19, 2021.
Abstract | Links | BibTeX | Tags:
@article{4521,
title = {Classification of Greek olive from different regions by machine learning - aided Laser - Induced Breakdown Spectroscopy and Absorption Spectroscopy},
author = {Nikolaos Gyftokostas and Eleni Nanou and Dimitrios Stefas and Vasileios Kokkinos and Christos Bouras and Stelios Couris},
url = {https://telematics3.upatras.gr/s41598-021-84941-z_0/},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Open Access Journal, MDPI, Special Issue Characterization of Olive Products from Greece},
volume = {26},
pages = {1 - 19},
abstract = {In the present work, the emission and the absorption spectra of numerous Greek olive oil samples and mixtures of them, obtained by two spectroscopic techniques, namely Laser-Induced Breakdown Spectroscopy (LIBS) and Absorption Spectroscopy, and aided by machine learning algorithms, were employed for the discrimination/classification of olive oils regarding their geographical origin. Both emission and absorption spectra were initially preprocessed by means of Principal Component Analysis (PCA) and were subsequently used for the construction of predictive models, employing Linear Discriminant Analysis (LDA) and Support Vector Machines (SVM). All
data analysis methodologies were validated by both “k-fold” cross-validation and external validation methods. In all cases, very high classification accuracies were found, up to 100%. The present results demonstrate the advantages of machine learning implementation for improving the capabilities of these spectroscopic techniques as tools for efficient olive oil quality monitoring and control.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In the present work, the emission and the absorption spectra of numerous Greek olive oil samples and mixtures of them, obtained by two spectroscopic techniques, namely Laser-Induced Breakdown Spectroscopy (LIBS) and Absorption Spectroscopy, and aided by machine learning algorithms, were employed for the discrimination/classification of olive oils regarding their geographical origin. Both emission and absorption spectra were initially preprocessed by means of Principal Component Analysis (PCA) and were subsequently used for the construction of predictive models, employing Linear Discriminant Analysis (LDA) and Support Vector Machines (SVM). All
data analysis methodologies were validated by both “k-fold” cross-validation and external validation methods. In all cases, very high classification accuracies were found, up to 100%. The present results demonstrate the advantages of machine learning implementation for improving the capabilities of these spectroscopic techniques as tools for efficient olive oil quality monitoring and control.
data analysis methodologies were validated by both “k-fold” cross-validation and external validation methods. In all cases, very high classification accuracies were found, up to 100%. The present results demonstrate the advantages of machine learning implementation for improving the capabilities of these spectroscopic techniques as tools for efficient olive oil quality monitoring and control.
Bouras, Christos; Gkamas, Apostolos; Kokkinos, Vasileios; Papachristos, Nikolaos
Performance Evaluation of Monitoring IoT Systems using LoRaWan Journal Article
In: Telecommunication Systems, Springer Verlang, pp. 295 - 308 , 2021.
Abstract | Links | BibTeX | Tags:
@article{4576,
title = {Performance Evaluation of Monitoring IoT Systems using LoRaWan},
author = {Christos Bouras and Apostolos Gkamas and Vasileios Kokkinos and Nikolaos Papachristos},
url = {https://telematics3.upatras.gr/telecommunicationssystems2021/},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Telecommunication Systems, Springer Verlang},
pages = {295 - 308 },
abstract = {The proliferation of smart devices, or even better, IoT devices, has led to the widespread development of applications that take advantage of these devices. Of particular interest is the precise localization of such a device. However, these use cases become extremely difficult when connectivity to end-devices is required even in areas where the signal is too low or different technologies co-exist for the transmission of the data. In this research work, we study LoRaWan and Wi-Fi as two possible candidates for data transmission. We are particularly focused on the study of the above technologies in terms of performance as well as application development that can be used as rescue monitoring systems. For this reason, we start by describing LoRa as an ideal low power and long-distance communication protocol on the IoT devices compared to the Wi-Fi network. We perform various simulations in terms of time on air transmission, bit error rate by changing important metrics to study the behavior of the whole mechanism. Based on our simulations, the main findings highlight that the contribution of a Spreading Factor (SF) and bandwidth (BW) optimizations can be applied to real hardware for real Search and Rescue (SAR) cases giving improved results in case of coverage and battery extension applications. As a continuation of our research, we developed a monitor application that collects and visualizes data from end-nodes (wearables). These data are processed gateway and network server to The Things Network (TTN) for further analysis. The proposed solution can be used in different rescue monitor scenarios such as identifying and find individuals of vulnerable groups or those belonging to group of people with a high probability of being lost. The purpose of the above solution is to overcome monitor problems on SAR cases, compare with WiFi and suggest a module supporting both technologies in order to be used in real experiments.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The proliferation of smart devices, or even better, IoT devices, has led to the widespread development of applications that take advantage of these devices. Of particular interest is the precise localization of such a device. However, these use cases become extremely difficult when connectivity to end-devices is required even in areas where the signal is too low or different technologies co-exist for the transmission of the data. In this research work, we study LoRaWan and Wi-Fi as two possible candidates for data transmission. We are particularly focused on the study of the above technologies in terms of performance as well as application development that can be used as rescue monitoring systems. For this reason, we start by describing LoRa as an ideal low power and long-distance communication protocol on the IoT devices compared to the Wi-Fi network. We perform various simulations in terms of time on air transmission, bit error rate by changing important metrics to study the behavior of the whole mechanism. Based on our simulations, the main findings highlight that the contribution of a Spreading Factor (SF) and bandwidth (BW) optimizations can be applied to real hardware for real Search and Rescue (SAR) cases giving improved results in case of coverage and battery extension applications. As a continuation of our research, we developed a monitor application that collects and visualizes data from end-nodes (wearables). These data are processed gateway and network server to The Things Network (TTN) for further analysis. The proposed solution can be used in different rescue monitor scenarios such as identifying and find individuals of vulnerable groups or those belonging to group of people with a high probability of being lost. The purpose of the above solution is to overcome monitor problems on SAR cases, compare with WiFi and suggest a module supporting both technologies in order to be used in real experiments.
Gyftokostas, Nikolaos; Stefas, Dimitrios; Kokkinos, Vasileios; Bouras, Christos; Couris, Stelios
Laser-Induced Breakdown Spectroscopy coupled with machine learning as a tool for olive oil authenticity and geographic discrimination Journal Article
In: Scientific Reports, Nature Research Journals, vol. 11, pp. 1 - 11, 2021.
Abstract | Links | BibTeX | Tags:
@article{4520,
title = {Laser-Induced Breakdown Spectroscopy coupled with machine learning as a tool for olive oil authenticity and geographic discrimination},
author = {Nikolaos Gyftokostas and Dimitrios Stefas and Vasileios Kokkinos and Christos Bouras and Stelios Couris},
url = {https://telematics3.upatras.gr/s41598-021-84941-z/},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Scientific Reports, Nature Research Journals},
volume = {11},
pages = {1 - 11},
abstract = {Olive oil is a basic element of the Mediterranean diet and a key product for the economies of the Mediterranean countries. Thus, there is an added incentive in the olive oil business for fraud through practices like adulteration and mislabeling. In the present work, Laser Induced Breakdown Spectroscopy (LIBS) assisted by machine learning is used for the classification of 139 virgin olive oils in terms of their geographical origin. The LIBS spectra of these olive oil samples were used to train different machine learning algorithms, namely LDA, ERTC, RFC, XGBoost, and to assess their classification performance. In addition, the variable importance of the spectral features was calculated, for the identification of the most important ones for the classification performance and to reduce their number for the algorithmic training. The algorithmic training was evaluated and tested by means of classification reports, confusion matrices and by external validation procedure as well. The present results demonstrate that machine learning aided LIBS can be a powerful and efficient tool for the rapid authentication of the geographic origin of virgin olive oil.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Olive oil is a basic element of the Mediterranean diet and a key product for the economies of the Mediterranean countries. Thus, there is an added incentive in the olive oil business for fraud through practices like adulteration and mislabeling. In the present work, Laser Induced Breakdown Spectroscopy (LIBS) assisted by machine learning is used for the classification of 139 virgin olive oils in terms of their geographical origin. The LIBS spectra of these olive oil samples were used to train different machine learning algorithms, namely LDA, ERTC, RFC, XGBoost, and to assess their classification performance. In addition, the variable importance of the spectral features was calculated, for the identification of the most important ones for the classification performance and to reduce their number for the algorithmic training. The algorithmic training was evaluated and tested by means of classification reports, confusion matrices and by external validation procedure as well. The present results demonstrate that machine learning aided LIBS can be a powerful and efficient tool for the rapid authentication of the geographic origin of virgin olive oil.
Kokoris, Ioannis; Kokkinos, Vasileios; Michos, Evangelos; Kalogeropoulos, Rafail; Charalambides, Marios; Kounelis, Agisilaos; Iliadou, Eleni; Damianidis, Christos K.; Mallinis, Giorgos; Bouras, Christos; Dimopoulos, Panayotis
MAES_GR: A Web-Based, Spatially Enabled Field Survey Platform for the MAES Implementation in Greece Journal Article
In: Land, MDPI 2021, vol. 10, pp. 1 - 18, 2021.
Abstract | Links | BibTeX | Tags:
@article{4524,
title = {MAES_GR: A Web-Based, Spatially Enabled Field Survey Platform for the MAES Implementation in Greece},
author = {Ioannis Kokoris and Vasileios Kokkinos and Evangelos Michos and Rafail Kalogeropoulos and Marios Charalambides and Agisilaos Kounelis and Eleni Iliadou and Christos K. Damianidis and Giorgos Mallinis and Christos Bouras and Panayotis Dimopoulos},
url = {https://telematics3.upatras.gr/land-10-00381/},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Land, MDPI 2021},
volume = {10},
pages = {1 - 18},
abstract = {This study presents a standardized approach to collecting, registering, and reporting field-survey data for baseline MAES (Mapping and Assessment of Ecosystems and their Services) information in Greece. This is accomplished through a web-based platform (MAES_GR) exclusively developed under the relevant, nation-wide LIFE-IP 4 NATURA project. Based on the European Commission’s guidance for ecosystem condition (EC) and ecosystem services (ES) MAES studies, we conceptualized and structured an online platform to support EC and ES assessments, integrating all relevant fields of information needed for registering EC and ES parameters. A novel algorithm calculating EC was also developed and it is available as an integral part of the platform. The use of the MAES_GR platform was evaluated during nationwide field surveys efforts, increasing time efficiency and reducing costs. Field recording of EC and ES pinpoint spatial priorities for ecosystem restoration, conservation and sustainable development. This work highlights that MAES implementation can be favored by the use of technology tools such as mobile survey platforms, developed according to scientific needs and policy guidelines. Such tools, apart from the data inventory phase, can be used for data analysis, synthesis and extraction, providing timely, standardized information suitable for reporting at the local, regional, national and European Union scale.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This study presents a standardized approach to collecting, registering, and reporting field-survey data for baseline MAES (Mapping and Assessment of Ecosystems and their Services) information in Greece. This is accomplished through a web-based platform (MAES_GR) exclusively developed under the relevant, nation-wide LIFE-IP 4 NATURA project. Based on the European Commission’s guidance for ecosystem condition (EC) and ecosystem services (ES) MAES studies, we conceptualized and structured an online platform to support EC and ES assessments, integrating all relevant fields of information needed for registering EC and ES parameters. A novel algorithm calculating EC was also developed and it is available as an integral part of the platform. The use of the MAES_GR platform was evaluated during nationwide field surveys efforts, increasing time efficiency and reducing costs. Field recording of EC and ES pinpoint spatial priorities for ecosystem restoration, conservation and sustainable development. This work highlights that MAES implementation can be favored by the use of technology tools such as mobile survey platforms, developed according to scientific needs and policy guidelines. Such tools, apart from the data inventory phase, can be used for data analysis, synthesis and extraction, providing timely, standardized information suitable for reporting at the local, regional, national and European Union scale.
Bouras, Christos; Stefas, Dimitrios; Gyftokostas, Nikolaos; Kourelias, Panagiotis; Nanou, Eleni; Kokkinos, Vasileios; Couris, Stelios
In: Food Control, Elsevier Science, vol. 130, pp. 1-8, 2021.
Abstract | Links | BibTeX | Tags:
@article{4538,
title = {Discrimination of olive oils based on the olive cultivar origin by machine learning employing the fusion of emission and absorption spectroscopic data},
author = {Christos Bouras and Dimitrios Stefas and Nikolaos Gyftokostas and Panagiotis Kourelias and Eleni Nanou and Vasileios Kokkinos and Stelios Couris},
url = {https://telematics3.upatras.gr/1-s2-0-s0956713521004564-main-1/},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Food Control, Elsevier Science},
volume = {130},
pages = {1-8},
abstract = {In this work Laser-Induced Breakdown Spectroscopy (LIBS) and absorption spectroscopy aided by machine learning are employed for discriminating some extra virgin Greek olive oils of different olive cultivars for the first time. LIBS and absorption spectra of extra virgin olive oils belonging to Kolovi and Koroneiki cultivars, as well as mixtures of them, were collected, analyzed, and used to develop classification schemes employing Linear Discriminant Analysis and Gradient Boosting, the latter allowing the determination of the most important spectral features. Both algorithms were found to provide efficient classification of the olive oil spectra with accuracies exceeding 90%. Furthermore, for the first time, the emission spectra of LIBS were fused with the absorption spectra to create predictive models and their accuracies were found to be significantly improved. This work demonstrates the enhanced capabilities of LIBS and absorption spectroscopy and the potential of their combination for olive oil quality monitoring and control.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this work Laser-Induced Breakdown Spectroscopy (LIBS) and absorption spectroscopy aided by machine learning are employed for discriminating some extra virgin Greek olive oils of different olive cultivars for the first time. LIBS and absorption spectra of extra virgin olive oils belonging to Kolovi and Koroneiki cultivars, as well as mixtures of them, were collected, analyzed, and used to develop classification schemes employing Linear Discriminant Analysis and Gradient Boosting, the latter allowing the determination of the most important spectral features. Both algorithms were found to provide efficient classification of the olive oil spectra with accuracies exceeding 90%. Furthermore, for the first time, the emission spectra of LIBS were fused with the absorption spectra to create predictive models and their accuracies were found to be significantly improved. This work demonstrates the enhanced capabilities of LIBS and absorption spectroscopy and the potential of their combination for olive oil quality monitoring and control.
Bouras, Christos; Kokkinos, Vasileios; Michos, Evangelos
An online tool on sustainable water management Journal Article
In: Tourism: An International Interdisciplinary Journal, Institute for Tourism, Zagreb, Croatia, 2020, vol. 68, Νο4, pp. 450-465, 2020.
Abstract | Links | BibTeX | Tags:
@article{4502,
title = {An online tool on sustainable water management},
author = {Christos Bouras and Vasileios Kokkinos and Evangelos Michos},
url = {https://telematics3.upatras.gr/450-465-paper-06-tourism-2020-04eng/},
year = {2020},
date = {2020-01-01},
urldate = {2020-01-01},
journal = {Tourism: An International Interdisciplinary Journal, Institute for Tourism, Zagreb, Croatia, 2020},
volume = {68, Νο4},
pages = {450-465},
abstract = {Water demand strains supply capacity in the Mediterranean coastal areas, affecting negatively the maintenance of natural and cultural heritage. Tackling this subject, the “Coastal areas sustainable tourism water management in the Mediterranean - CASTWATER” project aims to support sustainable tourism water management in Mediterranean (MED) coastal areas, by improving the monitoring and assessment of the water sustainability performance of tourism. To this end, the elaboration of an online tool to monitor and assess sustainable tourism water management was envisaged and developed, primarily addressed to tourism sector small and medium-sized enterprises (SMEs). The CASTWATER online tool was designed to so as to provide two different functionalities. On the one hand, SMEs can self-evaluate their performance in sustainable water management and efficiently acknowledge possible actions that promote water efficiency in their tourism establishments. On the other hand, the tool measures, at both regional and local level, the levels of good governance and the effectiveness of water-tourism policies in order to improve sustainable water management. The approach presented in this work is heavily based on the initial technical specifications and end-user feedback, aiding SMEs in understanding, comparing, assessing and rating their performance regarding water efficiency and sustainable water manag},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Water demand strains supply capacity in the Mediterranean coastal areas, affecting negatively the maintenance of natural and cultural heritage. Tackling this subject, the “Coastal areas sustainable tourism water management in the Mediterranean - CASTWATER” project aims to support sustainable tourism water management in Mediterranean (MED) coastal areas, by improving the monitoring and assessment of the water sustainability performance of tourism. To this end, the elaboration of an online tool to monitor and assess sustainable tourism water management was envisaged and developed, primarily addressed to tourism sector small and medium-sized enterprises (SMEs). The CASTWATER online tool was designed to so as to provide two different functionalities. On the one hand, SMEs can self-evaluate their performance in sustainable water management and efficiently acknowledge possible actions that promote water efficiency in their tourism establishments. On the other hand, the tool measures, at both regional and local level, the levels of good governance and the effectiveness of water-tourism policies in order to improve sustainable water management. The approach presented in this work is heavily based on the initial technical specifications and end-user feedback, aiding SMEs in understanding, comparing, assessing and rating their performance regarding water efficiency and sustainable water manag
Bouras, Christos; Gkamas, Apostolos; Kokkinos, Vasileios; Papachristos, Nikolaos
Geolocation analysis for SAR systems using LoRaWAN Journal Article
In: International Journal of Communication Systems, Wiley InterScience, pp. 1 - 16, 2020.
Abstract | Links | BibTeX | Tags:
@article{4487,
title = {Geolocation analysis for SAR systems using LoRaWAN},
author = {Christos Bouras and Apostolos Gkamas and Vasileios Kokkinos and Nikolaos Papachristos},
url = {https://telematics3.upatras.gr/dac-4593/},
year = {2020},
date = {2020-01-01},
urldate = {2020-01-01},
journal = {International Journal of Communication Systems, Wiley InterScience},
pages = {1 - 16},
abstract = {Low Power Wide Area Network (LPWAN) technologies aiming to provide power-efficient solutions to the field of Internet of Things (IoT). Over the last years we have seen a significant development within the area of IoT applications. For many applications, the problem of localization (i.e. determine the physical location of nodes) is critical. An area study of such use case is also the rescue monitor systems. In this study, we start by describing a solution designed for the Long Range Wide Area Network (LoRaWAN) to localize position of IoT modules such as wearables used from vulnerable groups. Through performance study of the behavior of a LoRaWAN channel and using trilateration and RSSI information, the localization of an IoT wearable can be acquired within a small range. Routing people in need is one of the use cases the above mechanism could be integrated so as to be able to be tracked by familiar people. After that, we evaluate the usage of mathematical model of multilateration algorithms using Time Difference of Arrival (TDoA) as a solution for positioning over LoRaWAN. The research is carried out using simulations in Python by configuring the constant positions of the Gateways inside an outdoor area. The proposed algorithms can be integrated in application for tracking people at any time and especially routing people from vulnerable groups. Through multilateration and algorithm’s prediction, we can have an accuracy of 40-60m in location positioning, ideal for search and rescue use cases. We finally summarize the above algorithms’ estimation and general behavior in a SAR system.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Low Power Wide Area Network (LPWAN) technologies aiming to provide power-efficient solutions to the field of Internet of Things (IoT). Over the last years we have seen a significant development within the area of IoT applications. For many applications, the problem of localization (i.e. determine the physical location of nodes) is critical. An area study of such use case is also the rescue monitor systems. In this study, we start by describing a solution designed for the Long Range Wide Area Network (LoRaWAN) to localize position of IoT modules such as wearables used from vulnerable groups. Through performance study of the behavior of a LoRaWAN channel and using trilateration and RSSI information, the localization of an IoT wearable can be acquired within a small range. Routing people in need is one of the use cases the above mechanism could be integrated so as to be able to be tracked by familiar people. After that, we evaluate the usage of mathematical model of multilateration algorithms using Time Difference of Arrival (TDoA) as a solution for positioning over LoRaWAN. The research is carried out using simulations in Python by configuring the constant positions of the Gateways inside an outdoor area. The proposed algorithms can be integrated in application for tracking people at any time and especially routing people from vulnerable groups. Through multilateration and algorithm’s prediction, we can have an accuracy of 40-60m in location positioning, ideal for search and rescue use cases. We finally summarize the above algorithms’ estimation and general behavior in a SAR system.
Baumann, Kurt; Bouras, Christos; Kokkinos, Vasileios; Papachristos, Nikolaos; Stamos, Kostas
WiFiMon - A Tool for Wi-Fi Performance Monitoring and Verification Journal Article
In: International Journal of Wireless Networks and Broadband Technologies (IJWNBT), IGI Global, vol. 8, pp. 1-18, 2019.
Abstract | Links | BibTeX | Tags:
@article{4405,
title = {WiFiMon - A Tool for Wi-Fi Performance Monitoring and Verification},
author = {Kurt Baumann and Christos Bouras and Vasileios Kokkinos and Nikolaos Papachristos and Kostas Stamos},
url = {https://telematics3.upatras.gr/wifimon_-a-tool-for-wi-fi-performance-monitoring-and-verification/},
year = {2019},
date = {2019-01-01},
urldate = {2019-01-01},
journal = {International Journal of Wireless Networks and Broadband Technologies (IJWNBT), IGI Global},
volume = {8},
pages = {1-18},
abstract = {Measuring network quality of a wireless network as experienced by end-users is quite difficult, as there isn’t a single tool available that can record measurements on all sides of the system. The approach presented in this research work is based on the end-user feedback, giving the opportunity of visualization of network performance in real time. We initially present an overview of the developed tool, called WiFiMon, which has the ability to capture, record measurements and export statistics on the quality of Wi-Fi network as perceived by the end-users. The measurements are initiated by the end-users - without their intervention – after they visit a web page or use a mobile application. WiFiMon aims to give a clear understanding of the Wi-Fi network conditions by measuring specific parameters of the network, such as download/upload throughput, and correlate these measurements with raw data from various log files to obtain additional information regarding the performance of specific access points. The results reveal the functionality of the proposed tool and its scalability.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Measuring network quality of a wireless network as experienced by end-users is quite difficult, as there isn’t a single tool available that can record measurements on all sides of the system. The approach presented in this research work is based on the end-user feedback, giving the opportunity of visualization of network performance in real time. We initially present an overview of the developed tool, called WiFiMon, which has the ability to capture, record measurements and export statistics on the quality of Wi-Fi network as perceived by the end-users. The measurements are initiated by the end-users - without their intervention – after they visit a web page or use a mobile application. WiFiMon aims to give a clear understanding of the Wi-Fi network conditions by measuring specific parameters of the network, such as download/upload throughput, and correlate these measurements with raw data from various log files to obtain additional information regarding the performance of specific access points. The results reveal the functionality of the proposed tool and its scalability.
Bouras, Christos; Kanakis, Nikolaos; Kokkinos, Vasileios; Papachristos, Nikolaos; Vouyioukas, Demosthenes
MCS Selection Exploiting Femtocells Utilization in Multicast Transmissions Journal Article
In: International Journal of Communication Systems, Wiley InterScience, vol. 31, pp. 1 - 13 , 2018.
Abstract | Links | BibTeX | Tags:
@article{4259,
title = {MCS Selection Exploiting Femtocells Utilization in Multicast Transmissions},
author = {Christos Bouras and Nikolaos Kanakis and Vasileios Kokkinos and Nikolaos Papachristos and Demosthenes Vouyioukas},
url = {https://telematics3.upatras.gr/bouras_et_al-2018-international_journal_of_communication_systems-1/},
year = {2018},
date = {2018-01-01},
urldate = {2018-01-01},
journal = {International Journal of Communication Systems, Wiley InterScience},
volume = {31},
pages = {1 - 13 },
abstract = {Multicast-Broadcast over Single Frequency Network (MBSFN) technology, as introduced by the Long Term Evolution Advanced (LTE-A) group, is expected to be part of the upcoming cellular systems offering resource efficiency to broadcast services. MBSFN transmission is suitable to serve multicast groups searching the same content. In addition, the fast emerging technology of femtocells networks and their hybrid nature can lead to efficient resource sharing between non-subscribed users when located inside their coverage. The focus of this manuscript is twofold; firstly, we have contacted simulation experiments to compare the MBSFN transmission with the traditional PTP transmission for various femtocell distributions and network topology changes; secondly, a novel multicast transmissions mechanism is proposed from non-subscribed users who exploit femtocells resources for broadcast services, without limiting user’s data requirements. The simulation results lead to a significant system’s performance in terms of average throughput, total capacity and energy consumption.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Multicast-Broadcast over Single Frequency Network (MBSFN) technology, as introduced by the Long Term Evolution Advanced (LTE-A) group, is expected to be part of the upcoming cellular systems offering resource efficiency to broadcast services. MBSFN transmission is suitable to serve multicast groups searching the same content. In addition, the fast emerging technology of femtocells networks and their hybrid nature can lead to efficient resource sharing between non-subscribed users when located inside their coverage. The focus of this manuscript is twofold; firstly, we have contacted simulation experiments to compare the MBSFN transmission with the traditional PTP transmission for various femtocell distributions and network topology changes; secondly, a novel multicast transmissions mechanism is proposed from non-subscribed users who exploit femtocells resources for broadcast services, without limiting user’s data requirements. The simulation results lead to a significant system’s performance in terms of average throughput, total capacity and energy consumption.
Bouras, Christos; Kokkinos, Vasileios; Kollia, Anastasia; Papazois, Andreas
Analyzing Small - cells and Distributed Antenna Systems from Techno - economic Perspective Journal Article
In: International Journal of Wireless Networks and Broadband Technologies (IJWNBT), IGI Global, vol. 6, pp. 45-64, 2017.
Abstract | Links | BibTeX | Tags:
@article{4191,
title = {Analyzing Small - cells and Distributed Antenna Systems from Techno - economic Perspective},
author = {Christos Bouras and Vasileios Kokkinos and Anastasia Kollia and Andreas Papazois},
url = {https://telematics3.upatras.gr/analyzing-small-cells-and-distributed-antenna-systems-from-techno-economic-perspective/},
year = {2017},
date = {2017-01-01},
urldate = {2017-01-01},
journal = {International Journal of Wireless Networks and Broadband Technologies (IJWNBT), IGI Global},
volume = {6},
pages = {45-64},
abstract = {Next-generation of mobile technologies is expected to largely augment the system’s peak data rates and cut down on the round-trip delays. The main idea of using ultra-density or DAS (Distributed Antenna Systems) based on their properties, is that they are able to increase efficiency and expand network capacity without the need for more spectrum resources by redistributing the existing ones, depict them as the key solutions for the future mobile networks. Small cells and DAS were launched mainly for addressing the issue of limited connectivity indoors. There are several other important benefits of these technologies, which constitute them as bases for future generations of mobile networks, such as 5G (5G-PPP, 2014). Femtocells’ benefit is that they provide ultra-density, which is expected to be one of the essential features of 5G. Ultra-dense networks coexist with the existing macrocellular ones forming altogether heterogeneous networks and fulfill the requirements and the network’s future demands. Scientists and researchers have decided to move towards this direction by conducing several research activity in the area (Networld2020 ETP, 2014; IWPC, 2014). The future mobile networks are going to demand a large network coverage. DAS would be an ideal solution to deal with the limited spectrum, because it provides repeaters, that are connected to the antenna system. It also serves the augmenting numbers of the smart devices, that in the future will be connected to the Internet or the smart home devices of the owner’s home network as we move dynamically to the Internet of Things. This paper studies the techno-economic aspects of ultra-dense and DAS deployments. It presents the characteristics and advantages for all their parts, as well as a techno-economic modeling of these deployment types. The defined models are used for the investigation of the upper technologies from an economic point of view. They provide an insight in the future financial and pricing aspects of these solutions and consist a useful tool for the definition of financing and pricing policies towards economically viable deployments. The authors define models for selecting the most appropriate network architectural solution for public buildings’ indoor coverage. Cost, investment, materials, coverage and capacity are the parameters that are taken into account for the definition of their models. The main scientific contribution of this paper is that it includes multiple case-study examples of the techno-economic models as well as results of conducted experiments. It also analyzes and presents a techno-economic model and summarizes the main research activity in the particular field. The remaining part of this paper is structured as follows: the second section refers to the related research that has been conducted so far. The third section presents the architectures of ultra-dense and DAS deployments used in the models. In the following section we describe cost models for ultra-dense and DAS deployments. In the next section we define the parameterization of the cost models. In the sixth section we conduce some experimental scenarios and analyze the corresponding results. Finally, in the seventh section we conclude our paper with the most fundamental conclusions realized in the experimental procedure and in the final section we list some ideas for future research work in the field of mobile network technologies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Next-generation of mobile technologies is expected to largely augment the system’s peak data rates and cut down on the round-trip delays. The main idea of using ultra-density or DAS (Distributed Antenna Systems) based on their properties, is that they are able to increase efficiency and expand network capacity without the need for more spectrum resources by redistributing the existing ones, depict them as the key solutions for the future mobile networks. Small cells and DAS were launched mainly for addressing the issue of limited connectivity indoors. There are several other important benefits of these technologies, which constitute them as bases for future generations of mobile networks, such as 5G (5G-PPP, 2014). Femtocells’ benefit is that they provide ultra-density, which is expected to be one of the essential features of 5G. Ultra-dense networks coexist with the existing macrocellular ones forming altogether heterogeneous networks and fulfill the requirements and the network’s future demands. Scientists and researchers have decided to move towards this direction by conducing several research activity in the area (Networld2020 ETP, 2014; IWPC, 2014). The future mobile networks are going to demand a large network coverage. DAS would be an ideal solution to deal with the limited spectrum, because it provides repeaters, that are connected to the antenna system. It also serves the augmenting numbers of the smart devices, that in the future will be connected to the Internet or the smart home devices of the owner’s home network as we move dynamically to the Internet of Things. This paper studies the techno-economic aspects of ultra-dense and DAS deployments. It presents the characteristics and advantages for all their parts, as well as a techno-economic modeling of these deployment types. The defined models are used for the investigation of the upper technologies from an economic point of view. They provide an insight in the future financial and pricing aspects of these solutions and consist a useful tool for the definition of financing and pricing policies towards economically viable deployments. The authors define models for selecting the most appropriate network architectural solution for public buildings’ indoor coverage. Cost, investment, materials, coverage and capacity are the parameters that are taken into account for the definition of their models. The main scientific contribution of this paper is that it includes multiple case-study examples of the techno-economic models as well as results of conducted experiments. It also analyzes and presents a techno-economic model and summarizes the main research activity in the particular field. The remaining part of this paper is structured as follows: the second section refers to the related research that has been conducted so far. The third section presents the architectures of ultra-dense and DAS deployments used in the models. In the following section we describe cost models for ultra-dense and DAS deployments. In the next section we define the parameterization of the cost models. In the sixth section we conduce some experimental scenarios and analyze the corresponding results. Finally, in the seventh section we conclude our paper with the most fundamental conclusions realized in the experimental procedure and in the final section we list some ideas for future research work in the field of mobile network technologies.
Gkypali, Areti; Kokkinos, Vasileios; Bouras, Christos; Tsekouras, Kostas
Science parks and regional innovation performance in fiscal austerity era: Less in more Journal Article
In: Special Issue on GCW 2014, Small Business Economics, Springer Verlang, vol. 47, pp. 313-330, 2016.
Abstract | Links | BibTeX | Tags:
@article{4109,
title = {Science parks and regional innovation performance in fiscal austerity era: Less in more},
author = {Areti Gkypali and Vasileios Kokkinos and Christos Bouras and Kostas Tsekouras},
url = {https://telematics3.upatras.gr/sbe2016_si_bouras/},
year = {2016},
date = {2016-08-01},
urldate = {2016-08-01},
journal = {Special Issue on GCW 2014, Small Business Economics, Springer Verlang},
volume = {47},
pages = {313-330},
abstract = {European financial crisis has raised questions about the sustainability and the contribution of innovation anchors especially in Southern European countries such as Greece. This paper utilizes the concept of regional innovation systems (RISs) and introduces a methodological approach that allows for evaluating an Science and Technology Park’s (STP) contribution into the corresponding RIS performance, taking into consideration (1) the RIS idiosyncrasies, (2) the dominant role of government expenditures on R&D and (3) the underlying complexity of knowledge production and management, under alternative sets of restrictions imposed by fiscal consolidation on the preferences of authorities which design and implement Science, Technology and Innovation (STI) policies. Our framework relies on the estimation of a multi-input–multi-output latent knowledge production function approach and the corresponding efficiency indices. Data requirements are sourced from the Regional Innovation Scoreboard, for the four Greek regions and from a small-scale case study, with respect to the examined regional STP covering the period from 2000 to 2012. The main empirical findings highlight that the contribution of the examined STP in the corresponding RIS performance diminishes alongside with the decrease in GERD investment levels, with respect to all the efficiency indices. These findings are attributed to the structural characteristics of both the RIS and the STP under investigation, and capture their dependence on managing public financial resources for STI activities.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
European financial crisis has raised questions about the sustainability and the contribution of innovation anchors especially in Southern European countries such as Greece. This paper utilizes the concept of regional innovation systems (RISs) and introduces a methodological approach that allows for evaluating an Science and Technology Park’s (STP) contribution into the corresponding RIS performance, taking into consideration (1) the RIS idiosyncrasies, (2) the dominant role of government expenditures on R&D and (3) the underlying complexity of knowledge production and management, under alternative sets of restrictions imposed by fiscal consolidation on the preferences of authorities which design and implement Science, Technology and Innovation (STI) policies. Our framework relies on the estimation of a multi-input–multi-output latent knowledge production function approach and the corresponding efficiency indices. Data requirements are sourced from the Regional Innovation Scoreboard, for the four Greek regions and from a small-scale case study, with respect to the examined regional STP covering the period from 2000 to 2012. The main empirical findings highlight that the contribution of the examined STP in the corresponding RIS performance diminishes alongside with the decrease in GERD investment levels, with respect to all the efficiency indices. These findings are attributed to the structural characteristics of both the RIS and the STP under investigation, and capture their dependence on managing public financial resources for STI activities.
Asimakis, Konstantinos; Bouras, Christos; Kokkinos, Vasileios; Papazois, Andreas
Mobility - aware Power Control in MBSFN Journal Article
In: Telecommunications Systems, Springer Verlang (Special Issue on WMNC 2012), vol. 61, pp. 77-91, 2016.
Abstract | Links | BibTeX | Tags:
@article{3438,
title = {Mobility - aware Power Control in MBSFN},
author = {Konstantinos Asimakis and Christos Bouras and Vasileios Kokkinos and Andreas Papazois},
url = {https://telematics3.upatras.gr/telsys2016_bouras/},
year = {2016},
date = {2016-01-01},
urldate = {2016-01-01},
journal = {Telecommunications Systems, Springer Verlang (Special Issue on WMNC 2012)},
volume = {61},
pages = {77-91},
abstract = {Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN) within LTE systems is a feature that allows synchronous broadcasting of common data among neighboring cells. With MBSFN operation, mobile broadcast/multicast users are able to use inter-cell interference in a constructive way and to achieve increased bit-rates compared to when conventional broadcasting is used. In this manuscript, we present our work on the optimization of the power control for future mobile networks that employ MBSFN transmission. We propose a novel simulator and system optimizer that can minimize the individual cell’s transmission power by taking into account the changing positions of users. The system optimizer is based on a novel genetic algorithm, which is resistant to entrapment in local optima and makes use of mutations over the previous solutions in order to optimize the power consumption given the new users’ positions. The optimizer’s engine can be used in conjunction with the simulator or can be easily modi ed to receive real-time measurements from a real LTE network as an input. In order to read descriptions of the various scenarios, the simulator uses the eXtendable Temporal Network Description Language (XTNDL), a language that is also speci ed in this manuscript.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN) within LTE systems is a feature that allows synchronous broadcasting of common data among neighboring cells. With MBSFN operation, mobile broadcast/multicast users are able to use inter-cell interference in a constructive way and to achieve increased bit-rates compared to when conventional broadcasting is used. In this manuscript, we present our work on the optimization of the power control for future mobile networks that employ MBSFN transmission. We propose a novel simulator and system optimizer that can minimize the individual cell’s transmission power by taking into account the changing positions of users. The system optimizer is based on a novel genetic algorithm, which is resistant to entrapment in local optima and makes use of mutations over the previous solutions in order to optimize the power consumption given the new users’ positions. The optimizer’s engine can be used in conjunction with the simulator or can be easily modi ed to receive real-time measurements from a real LTE network as an input. In order to read descriptions of the various scenarios, the simulator uses the eXtendable Temporal Network Description Language (XTNDL), a language that is also speci ed in this manuscript.
Bouras, Christos; Diles, Georgios; Kokkinos, Vasileios; Papazois, Andreas
Transmission optimizing on dense femtocell deployments in 5G Journal Article
In: International Journal of Communication Systems, Wiley InterScience, vol. 29, pp. 2325 - 2438, 2016.
Abstract | Links | BibTeX | Tags:
@article{4108,
title = {Transmission optimizing on dense femtocell deployments in 5G},
author = {Christos Bouras and Georgios Diles and Vasileios Kokkinos and Andreas Papazois},
url = {https://telematics3.upatras.gr/bouras_et_al-2015-international_journal_of_communication_systems/},
year = {2016},
date = {2016-01-01},
urldate = {2016-01-01},
journal = {International Journal of Communication Systems, Wiley InterScience},
volume = {29},
pages = {2325 - 2438},
abstract = {In the upcoming generation of mobile networks, femtocells will play a major role because they provide cost-efficient improvement in data rates and coverage. High penetration is expected in the upcoming ultradense 5G networks, increasing the probability of femtocells’ clusters. This, in turn, will require interference mitigation techniques to protect nearby non-subscribed users, especially in weak macrocell signal areas. In this paper, we present a mechanism where multiple femtocells coordinate their transmission to serve multiple non-subscribed users through hybrid access. First, we introduce an algorithm that determines the spectrum allocation of femtocells’ hybrid access. The algorithm aims to compensate for the performance reduction of subscribed users, due to reduced spectrum. For the second step of the mechanism, we introduce a power control algorithm that balances the impact of hybrid access among all the members of the femtocell cluster. First, we investigate the case where only one femtocell operates in hybrid access, and then we refine the power control algorithm by allowing multiple femtocells in the same cluster to operate in hybrid mode and by taking into account the effect that any change in power transmission will have on neighbouring femtocells. Simulations for the evaluation of the hybrid access algorithm compared with closed and other hybrid access schemes show improvement in the throughput of the non-subscribed users connected to femtocell and the most impacted subscribed users at weak macrocell signal areas and in the fairness of the hybrid access application scheme.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In the upcoming generation of mobile networks, femtocells will play a major role because they provide cost-efficient improvement in data rates and coverage. High penetration is expected in the upcoming ultradense 5G networks, increasing the probability of femtocells’ clusters. This, in turn, will require interference mitigation techniques to protect nearby non-subscribed users, especially in weak macrocell signal areas. In this paper, we present a mechanism where multiple femtocells coordinate their transmission to serve multiple non-subscribed users through hybrid access. First, we introduce an algorithm that determines the spectrum allocation of femtocells’ hybrid access. The algorithm aims to compensate for the performance reduction of subscribed users, due to reduced spectrum. For the second step of the mechanism, we introduce a power control algorithm that balances the impact of hybrid access among all the members of the femtocell cluster. First, we investigate the case where only one femtocell operates in hybrid access, and then we refine the power control algorithm by allowing multiple femtocells in the same cluster to operate in hybrid mode and by taking into account the effect that any change in power transmission will have on neighbouring femtocells. Simulations for the evaluation of the hybrid access algorithm compared with closed and other hybrid access schemes show improvement in the throughput of the non-subscribed users connected to femtocell and the most impacted subscribed users at weak macrocell signal areas and in the fairness of the hybrid access application scheme.
Bouras, Christos; Kanakis, Nikos; Kokkinos, Vasileios; Papazois, Andreas
Deploying AL-FEC Protection with Online Algorithms for Multicast Services over Cellular Networks Journal Article
In: Wireless Networks, Springer Verlang, vol. 20, pp. 2109-2122, 2015.
Abstract | Links | BibTeX | Tags:
@article{3436,
title = {Deploying AL-FEC Protection with Online Algorithms for Multicast Services over Cellular Networks},
author = {Christos Bouras and Nikos Kanakis and Vasileios Kokkinos and Andreas Papazois},
url = {https://telematics3.upatras.gr/art_10-1007_s11276-014-0734-x/},
year = {2015},
date = {2015-01-01},
urldate = {2015-01-01},
journal = {Wireless Networks, Springer Verlang},
volume = {20},
pages = {2109-2122},
abstract = {Reliability control is a key concern on the evolution of mobile multicast services. To this direction, the use of forward error correction (FEC) on the application layer is widely adopted in several mobile multicast standards. FEC is a feedback free error control method, where the transmitter introduces in advance redundant information within the source data to enable receivers recovering arbitrary data erasures. On multicast delivery where retransmission-based error recovery methods are not ecient, the most suitable error control method is the use of application layer forward error correction (AL-FEC) codes. In this work, we introduce novel AL-FEC deployment policies over mobile multicast environments utilizing online algorithms. We aim at the ecient application of AL-FEC protection with RaptorQ codes over multicast delivery in the context of competitive analysis. We provide a competitiveness analysis model of AL-FEC application over mobile multicast environments. Furthermore, we propose two online algorithms adjusting the introduced redundancy of AL-FEC protection according to several FEC encoding parameters and constraints of mobile multicast delivery.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Reliability control is a key concern on the evolution of mobile multicast services. To this direction, the use of forward error correction (FEC) on the application layer is widely adopted in several mobile multicast standards. FEC is a feedback free error control method, where the transmitter introduces in advance redundant information within the source data to enable receivers recovering arbitrary data erasures. On multicast delivery where retransmission-based error recovery methods are not ecient, the most suitable error control method is the use of application layer forward error correction (AL-FEC) codes. In this work, we introduce novel AL-FEC deployment policies over mobile multicast environments utilizing online algorithms. We aim at the ecient application of AL-FEC protection with RaptorQ codes over multicast delivery in the context of competitive analysis. We provide a competitiveness analysis model of AL-FEC application over mobile multicast environments. Furthermore, we propose two online algorithms adjusting the introduced redundancy of AL-FEC protection according to several FEC encoding parameters and constraints of mobile multicast delivery.
Antonis, Konstantinos; Bouras, Christos; D’Elia, Fabrizio; Vincenzo, Annalisa Di; Diles, Georgios; Kokkinos, Vasileios; Koskeris, Andreas
Broadband and e - Government Services in South East Europe: Comparative Analysis, Impact and Policy Recommendations Journal Article
In: International Journal of Interdisciplinary Telecommunications and Networking, IGI Global, vol. 6, pp. 39-56, 2015.
Abstract | Links | BibTeX | Tags:
@article{4060,
title = {Broadband and e - Government Services in South East Europe: Comparative Analysis, Impact and Policy Recommendations},
author = {Konstantinos Antonis and Christos Bouras and Fabrizio D’Elia and Annalisa Di Vincenzo and Georgios Diles and Vasileios Kokkinos and Andreas Koskeris},
url = {https://telematics3.upatras.gr/broadband-and-e-government-services-in-south-east-europe_-comparative-analysis-impact-and-policy-recommendations/},
year = {2015},
date = {2015-01-01},
urldate = {2015-01-01},
journal = {International Journal of Interdisciplinary Telecommunications and Networking, IGI Global},
volume = {6},
pages = {39-56},
abstract = {The European Commission acknowledging the significance of broadband for the improvement of citizen welfare and its economic benefits, has put in place targets for the diffusion of broadband to all citizens and businesses in the European Union. This manuscript comparatively assesses the current state of affairs in broadband and digital public services in selected South East Europe (SEE) countries in order to identify weaknesses and highlight strengths, and attempts to measure the impact and effectiveness of broadband on the economy. To this direction, the authors focus on evaluating the correlation between broadband and growth and employment. They also estimate the savings achieved by the usage of e-services and the potential savings that will follow their increased utilization over the next years. The analysis is followed by a number of recommendations that aim to support informed decision making. The manuscript builds on four surveys that took place during the second quarter of 2013.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The European Commission acknowledging the significance of broadband for the improvement of citizen welfare and its economic benefits, has put in place targets for the diffusion of broadband to all citizens and businesses in the European Union. This manuscript comparatively assesses the current state of affairs in broadband and digital public services in selected South East Europe (SEE) countries in order to identify weaknesses and highlight strengths, and attempts to measure the impact and effectiveness of broadband on the economy. To this direction, the authors focus on evaluating the correlation between broadband and growth and employment. They also estimate the savings achieved by the usage of e-services and the potential savings that will follow their increased utilization over the next years. The analysis is followed by a number of recommendations that aim to support informed decision making. The manuscript builds on four surveys that took place during the second quarter of 2013.
Bouras, Christos; Diles, Georgios; Kokkinos, Vasileios; Kontodimas, Konstantinos; Papazois, Andreas
A Simulation Framework for Evaluating Interference Mitigation Techniques in Heterogeneous Cellurar Environments Journal Article
In: Wireless Personal Communications, Springer Verlang, vol. 77, pp. 1213-1237, 2014.
Abstract | Links | BibTeX | Tags:
@article{3440,
title = {A Simulation Framework for Evaluating Interference Mitigation Techniques in Heterogeneous Cellurar Environments},
author = {Christos Bouras and Georgios Diles and Vasileios Kokkinos and Konstantinos Kontodimas and Andreas Papazois},
url = {https://telematics3.upatras.gr/wpcfinal/},
year = {2014},
date = {2014-01-01},
urldate = {2014-01-01},
journal = {Wireless Personal Communications, Springer Verlang},
volume = {77},
pages = {1213-1237},
abstract = {Femtocells present an attractive solution for the improvement of a mobile network services providing better data rates and coverage. Since their deployment results to a heterogeneous network where two layers must utilize the available spectrum, issues of interference arise. A method to address this challenge, is investigating the locations of the newly installed FBS, and enforcing a power controlled transmission of all FBSs that achieves optimal and fair overall performance. Another option that becomes available in inter-cell interference cancellation (ICIC) macrocell environments, is utilizing the available spectrum to complete or partly avoid co-channel operation. In this work, we provide a simulation framework that allows the creation of custom, high configurable, user defined topologies of femtocells with power control and frequency allocation capabilities. It allows the investigation of the margin of improvement in interference when these methods are applied and may work as a decision tool for planning and evaluating heterogeneous networks. To showcase the frameworks
capabilities, we evaluate and study the behaviour of custom deployed femtocells/macrocells networks and examine the cross-tier interference issues. Facilitated by the framework, we enforce and evaluate each interference mitigation technique for different femtocells? deployment densities. Finally, we compare the results of each method in terms of total throughput, spectral efficiency and cell-edge users performance.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Femtocells present an attractive solution for the improvement of a mobile network services providing better data rates and coverage. Since their deployment results to a heterogeneous network where two layers must utilize the available spectrum, issues of interference arise. A method to address this challenge, is investigating the locations of the newly installed FBS, and enforcing a power controlled transmission of all FBSs that achieves optimal and fair overall performance. Another option that becomes available in inter-cell interference cancellation (ICIC) macrocell environments, is utilizing the available spectrum to complete or partly avoid co-channel operation. In this work, we provide a simulation framework that allows the creation of custom, high configurable, user defined topologies of femtocells with power control and frequency allocation capabilities. It allows the investigation of the margin of improvement in interference when these methods are applied and may work as a decision tool for planning and evaluating heterogeneous networks. To showcase the frameworks
capabilities, we evaluate and study the behaviour of custom deployed femtocells/macrocells networks and examine the cross-tier interference issues. Facilitated by the framework, we enforce and evaluate each interference mitigation technique for different femtocells? deployment densities. Finally, we compare the results of each method in terms of total throughput, spectral efficiency and cell-edge users performance.
capabilities, we evaluate and study the behaviour of custom deployed femtocells/macrocells networks and examine the cross-tier interference issues. Facilitated by the framework, we enforce and evaluate each interference mitigation technique for different femtocells? deployment densities. Finally, we compare the results of each method in terms of total throughput, spectral efficiency and cell-edge users performance.
Bouras, Christos; Antonis, Konstantinos; Diles, Georgios; Kokkinos, Vasileios; Loukopoulos, Leonidas
Economic Broadband Development through Infrastructure Sharing Journal Article
In: International Journal of Business Data Communications and Networking, IGI Global, vol. 10, pp. 21-42, 2014.
Abstract | Links | BibTeX | Tags:
@article{4106,
title = {Economic Broadband Development through Infrastructure Sharing},
author = {Christos Bouras and Konstantinos Antonis and Georgios Diles and Vasileios Kokkinos and Leonidas Loukopoulos},
url = {https://telematics3.upatras.gr/economic-broadband-development-through-infrastructure-sharing/},
year = {2014},
date = {2014-01-01},
urldate = {2014-01-01},
journal = {International Journal of Business Data Communications and Networking, IGI Global},
volume = {10},
pages = {21-42},
abstract = {Broadband is a public utility with positive effects on competitiveness, employment and growth. Although evidence shows that broadband development is increasing, this increment is not homogeneous between urban and rural areas. The main factor is the high cost for deploying next generation networks in rural areas, and especially the cost linked to civil engineering works. In order to overcome the investment challenges arising in the context of broadband deployment, the European Commission made mandatory the sharing of existing telecommunication and non-telecommunication infrastructures and facilities. This manuscript proposes and presents a novel tool that enables the estimation of the expected savings from exploiting existing infrastructures when deploying a broadband network. This is followed by a number of general principles and recommendations that policy makers and national authorities could embrace to diminish deployment costs and promote broadband deployment.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Broadband is a public utility with positive effects on competitiveness, employment and growth. Although evidence shows that broadband development is increasing, this increment is not homogeneous between urban and rural areas. The main factor is the high cost for deploying next generation networks in rural areas, and especially the cost linked to civil engineering works. In order to overcome the investment challenges arising in the context of broadband deployment, the European Commission made mandatory the sharing of existing telecommunication and non-telecommunication infrastructures and facilities. This manuscript proposes and presents a novel tool that enables the estimation of the expected savings from exploiting existing infrastructures when deploying a broadband network. This is followed by a number of general principles and recommendations that policy makers and national authorities could embrace to diminish deployment costs and promote broadband deployment.