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161 results on '"Vrakas, Dimitris"'

1. Does Noise Affect Housing Prices? A Case Study in the Urban Area of Thessaloniki

Author

Kamtziridis, Georgios, Vrakas, Dimitris, and Tsoumakas, Grigorios

Subjects
Computer Science - Machine Learning
Abstract

Real estate markets depend on various methods to predict housing prices, including models that have been trained on datasets of residential or commercial properties. Most studies endeavor to create more accurate machine learning models by utilizing data such as basic property characteristics as well as urban features like distances from amenities and road accessibility. Even though environmental factors like noise pollution can potentially affect prices, the research around this topic is limited. One of the reasons is the lack of data. In this paper, we reconstruct and make publicly available a general purpose noise pollution dataset based on published studies conducted by the Hellenic Ministry of Environment and Energy for the city of Thessaloniki, Greece. Then, we train ensemble machine learning models, like XGBoost, on property data for different areas of Thessaloniki to investigate the way noise influences prices through interpretability evaluation techniques. Our study provides a new noise pollution dataset that not only demonstrates the impact noise has on housing prices, but also indicates that the influence of noise on prices significantly varies among different areas of the same city., Comment: 24 pages, 20 figures, 7 tables

Published
2023

2. Intelligent Energy Management Systems -- A Review

Author

Mischos, Stavros, Dalagdi, Eleanna, and Vrakas, Dimitris

Subjects
Computer Science - Computers and Society
Abstract

Climate change has become a major problem for humanity in the last two decades. One of the reasons that caused it, is our daily energy waste. People consume electricity in order to use home/work appliances and devices and also reach certain levels of comfort while working or being at home. However, even though the environmental impact of this behavior is not immediately observed, it leads to increased CO2 emissions coming from energy generation from power plants. Confronting such a problem efficiently will affect both the environment and our society. Monitoring energy consumption in real-time, changing energy wastage behavior of occupants and using automations with incorporated energy savings scenarios, are ways to decrease global energy footprint. In this review, we study intelligent systems for energy management in residential, commercial and educational buildings, classifying them in two major categories depending on whether they provide direct or indirect control. The article also discusses what the strengths and weaknesses are, which optimization techniques do they use and finally, provide insights about how these systems can be improved in the future.

Published
2022

3. Machine Learning Approaches for Non-Intrusive Home Absence Detection Based on Appliance Electrical Use

Author

Lentzas, Athanasios and Vrakas, Dimitris

Subjects
Computer Science - Machine Learning, Computer Science - Artificial Intelligence, Computer Science - Neural and Evolutionary Computing, Electrical Engineering and Systems Science - Signal Processing
Abstract

Home absence detection is an emerging field on smart home installations. Identifying whether or not the residents of the house are present, is important in numerous scenarios. Possible scenarios include but are not limited to: elderly people living alone, people suffering from dementia, home quarantine. The majority of published papers focus on either pressure / door sensors or cameras in order to detect outing events. Although the aforementioned approaches provide solid results, they are intrusive and require modifications for sensor placement. In our work, appliance electrical use is investigated as a means for detecting the presence or absence of residents. The energy use is the result of power disaggregation, a non intrusive / non invasive sensing method. Since a dataset providing energy data and ground truth for home absence is not available, artificial outing events were introduced on the UK-DALE dataset, a well known dataset for Non Intrusive Load Monitoring (NILM). Several machine learning algorithms were evaluated using the generated dataset. Benchmark results have shown that home absence detection using appliance power consumption is feasible., Comment: 20 pages,submitted to "Expert Systems with Applications"

Published
2022
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4. From Robot Self-Localization to Global-Localization: An RSSI Based Approach

Author

Lentzas, Athanasios and Vrakas, Dimitris

Subjects
Computer Science - Robotics
Abstract

Localization is a crucial task for autonomous mobile robots in order to successfully move to goal locations in their environment. Usually, this is done in a robot-centric manner, where the robot maintains a map with its body in the center. In swarm robotics applications, where a group of robots needs to coordinate in order to achieve their common goals, robot-centric localization will not suffice as each member of the swarm has its own frame of reference. One way to deal with this problem is to create, maintain and share a common map (global coordinate system), among the members of the swarm. This paper presents an approach to global localization for a group of robots in unknown, GPS and landmark free environments that extends the localization scheme of the LadyBug algorithm. The main idea relies on members of the swarm staying still and acting as beacons, emitting electromagnetic signals. These stationary robots form a global frame of reference and the rest of the group localize themselves in it using the Received Signal Strength Indicator (RSSI). The proposed method is evaluated, and the results obtained from the experiments are promising., Comment: In Proceedings AREA 2023, arXiv:2310.00333

Published
2021
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7. Entropy Based Feature Pooling in Speech Command Classification

Author

Nalmpantis, Christoforos, Vrysis, Lazaros, Vlachava, Danai, Papageorgiou, Lefteris, Vrakas, Dimitris, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, and Arai, Kohei, editor

Published
2021
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8. Attention in Recurrent Neural Networks for Energy Disaggregation

Author

Virtsionis Gkalinikis, Nikolaos, Nalmpantis, Christoforos, Vrakas, Dimitris, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Appice, Annalisa, editor, Tsoumakas, Grigorios, editor, Manolopoulos, Yannis, editor, and Matwin, Stan, editor

Published
2020
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9. The Tomaco Hybrid Matching Framework for SAWSDL Semantic Web Services

Author

Stavropoulos, Thanos G., Andreadis, Stelios, Bassiliades, Nick, Vrakas, Dimitris, and Vlahavas, Ioannis

Subjects
Computer Science - Software Engineering, Computer Science - Artificial Intelligence, H.3.5
Abstract

This work aims to resolve issues related to Web Service retrieval, also known as Service Selection, Discovery or essentially Matching, in two directions. Firstly, a novel matching algorithm for SAWSDL is introduced. The algorithm is hybrid in nature, combining novel and known concepts, such as a logic-based strategy and syntactic text-similarity measures on semantic annotations and textual descriptions. A plugin for the S3 contest environment was developed, in order to position Tomaco amongst state-of-the-art in an objective, reproducible manner. Evaluation showed that Tomaco ranks high amongst state of the art, especially for early recall levels. Secondly, this work introduces the Tomaco web application, which aims to accelerate the wide-spread adoption of Semantic Web Service technologies and algorithms while targeting the lack of user-friendly applications in this field. Tomaco integrates a variety of configurable matching algorithms proposed in this paper. It, finally, allows discovery of both existing and user-contributed service collections and ontologies, serving also as a service registry., Comment: Under review. Keywords: Web Services Discovery, Intelligent Web Services and Semantic Web, Internet reasoning services, Web-based services

Published
2014

12. Imaging Time-Series for NILM

Author

Kyrkou, Lamprini, Nalmpantis, Christoforos, Vrakas, Dimitris, Barbosa, Simone Diniz Junqueira, Editorial Board Member, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Kotenko, Igor, Editorial Board Member, Yuan, Junsong, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Macintyre, John, editor, Iliadis, Lazaros, editor, Maglogiannis, Ilias, editor, and Jayne, Chrisina, editor

Published
2019
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13. A Benchmark Framework to Evaluate Energy Disaggregation Solutions

Author

Symeonidis, Nikolaos, Nalmpantis, Christoforos, Vrakas, Dimitris, Barbosa, Simone Diniz Junqueira, Editorial Board Member, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Kotenko, Igor, Editorial Board Member, Yuan, Junsong, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Macintyre, John, editor, Iliadis, Lazaros, editor, Maglogiannis, Ilias, editor, and Jayne, Chrisina, editor

Published
2019
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14. Signal2Vec: Time Series Embedding Representation

Author

Nalmpantis, Christoforos, Vrakas, Dimitris, Barbosa, Simone Diniz Junqueira, Editorial Board Member, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Kotenko, Igor, Editorial Board Member, Yuan, Junsong, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Macintyre, John, editor, Iliadis, Lazaros, editor, Maglogiannis, Ilias, editor, and Jayne, Chrisina, editor

Published
2019
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23. Policies Production System for Ambient Intelligence Environments

Author

Kotsiopoulos, Nikos P., Vrakas, Dimitris, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Kobsa, Alfred, editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Weikum, Gerhard, editor, Goebel, Randy, editor, Tanaka, Yuzuru, editor, Wahlster, Wolfgang, editor, Siekmann, Jörg, editor, Likas, Aristidis, editor, Blekas, Konstantinos, editor, and Kalles, Dimitris, editor

Published
2014
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24. AI in Greece: The Case of Research on Linked Geospatial Data

Author

Koubarakis, Manolis, Vouros, George, Chalkiadakis, Georgios, Plagianakos, Vassilis, Tjortjis, Christos, Kavallieratou, Ergina, Vrakas, Dimitris, Mavridis, Nikolaos, Petasis, Georgios, Blekas, Konstantinos, and Krithara, Anastasia

Subjects
Artificial intelligence -- Research, Geospatial data -- Case studies, Nonprofit organizations -- Services, Artificial intelligence, Business
Abstract

We survey the AI research carried out in Greece recently. We concentrate on the case of linked geospatial data, an area with significant practical importance, very interesting research results, and [...]

Published
2018

26. A System for Energy Savings in an Ambient Intelligence Environment

Author

Stavropoulos, Thanos G., Vrakas, Dimitris, Arvanitidis, Alexandros, Vlahavas, Ioannis, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Kranzlmüller, Dieter, editor, and Toja, A Min, editor

Published
2011
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30. System Architecture for a Smart University Building

Author

Stavropoulos, Thanos G., Tsioliaridou, Ageliki, Koutitas, George, Vrakas, Dimitris, Vlahavas, Ioannis, Hutchison, David, Kanade, Takeo, Kittler, Josef, Kleinberg, Jon M., Mattern, Friedemann, Mitchell, John C., Naor, Moni, Nierstrasz, Oscar, Pandu Rangan, C., Steffen, Bernhard, Sudan, Madhu, Terzopoulos, Demetri, Tygar, Doug, Vardi, Moshe Y., Weikum, Gerhard, Diamantaras, Konstantinos, editor, Duch, Wlodek, editor, and Iliadis, Lazaros S., editor

Published
2010
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31. Semantic Awareness in Automated Web Service Composition through Planning

Author

Hatzi, Ourania, Vrakas, Dimitris, Bassiliades, Nick, Anagnostopoulos, Dimosthenis, Vlahavas, Ioannis, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Goebel, Randy, editor, Siekmann, Jörg, editor, Wahlster, Wolfgang, editor, Konstantopoulos, Stasinos, editor, Perantonis, Stavros, editor, Karkaletsis, Vangelis, editor, Spyropoulos, Constantine D., editor, and Vouros, George, editor

Published
2010
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33. Towards Automatic Synthesis of Educational Resources Through Automated Planning

Author

Vrakas, Dimitris, Kokkoras, Fotis, Bassiliades, Nick, Vlahavas, Ioannis, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Dough, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Carbonell, Jaime G., editor, Siekmann, Jörg, editor, Antoniou, Grigoris, editor, Potamias, George, editor, Spyropoulos, Costas, editor, and Plexousakis, Dimitris, editor

Published
2006
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35. Using the k-Nearest Problems for Adaptive Multicriteria Planning

Author

Tsoumakas, Grigorios, Vrakas, Dimitris, Bassiliades, Nick, Vlahavas, Ioannis, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Carbonell, Jaime G., editor, Siekmann, Jörg, editor, Vouros, George A., editor, and Panayiotopoulos, Themistoklis, editor

Published
2004
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47. Use of multimedia and the World Wide Web in civil engineering learning

Author

Golias, Michael, Angelides, Demos C., Marnas, Stelios I., and Vrakas, Dimitris

Subjects
Internet -- Usage, Engineering -- Study and teaching, Internet, Business, Education, Engineering and manufacturing industries
Abstract

The case study method, which has been proven to be a very useful learning tool, can be further enhanced with the use of multimedia and the World Wide Web. This paper demonstrates multimedia and Web-based enhancement with the design and construction of a port, a large-scale civil engineering project. The main purpose was to create an educational tool that brings into the classroom a 'real-life' design and construction problem, including the construction field, operation of equipment, and details of construction methods. This enables civil engineering students to better understand the details of the planning, design, and construction of a complicated project. Furthermore, through the use of evaluation tests, feedback on the students' understanding of the case study can be provided to both the students and the educator. This application can be expanded beyond an academic environment for use as a learning tool in a business environment, which may be especially beneficial for new engineers. CE Database subject headings: Case reports; Information technology (IT); Multimedia; Internet; Training; Engineering education.

Published
2005

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