Chrysostomos Tsoukalas, D. Dervos, Jorge Martínez Gil, J. F. A. Montes
{"title":"TheMa: An API for Mining Linked Datasets","authors":"Chrysostomos Tsoukalas, D. Dervos, Jorge Martínez Gil, J. F. A. Montes","doi":"10.1109/PCI.2012.58","DOIUrl":"https://doi.org/10.1109/PCI.2012.58","url":null,"abstract":"Linked Open Data is a paradigm for linking the data available on the Web in a structured format in order to make it accessible for computers and people. This leads to having more people and services publish their data on the web and as a result the graph that contains all this information is getting bigger. This paper proposes the usage of some network analysis algorithms on a Linked Dataset in order to extract useful information which in turn leads to a better understanding/interpretation of the data involved, plus comprises a first step in the direction of mining hidden information from the dataset.","PeriodicalId":131195,"journal":{"name":"2012 16th Panhellenic Conference on Informatics","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116710104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Using Microworlds to Introduce Programming to Novices","authors":"Y. Papadopoulos, Stergios Tegos","doi":"10.1109/PCi.2012.18","DOIUrl":"https://doi.org/10.1109/PCi.2012.18","url":null,"abstract":"Introduction to programming is a traditional and compulsory course for first year Computer Science students. However, research in the field of computer science education has highlighted that many students lack on problem solving and computational thinking skills. These issues provoke questions in the academic community as to whether the learning methodology of introductory to programming courses is appropriate. As regards the pedagogical procedure in general, the teacher-centered model was amended with the introduction of Interactive Learning Environments, which promote distributed learning. In this paper, we examine the fundamental skills needed for introductory to programming courses. Additionally, we focus on some of the most popular micro worlds and evaluate them in terms of educational suitability.","PeriodicalId":131195,"journal":{"name":"2012 16th Panhellenic Conference on Informatics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131925082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Parallel Implementation of the Slope One Algorithm for Collaborative Filtering","authors":"Efthalia Karydi, K. Margaritis","doi":"10.1109/PCi.2012.34","DOIUrl":"https://doi.org/10.1109/PCi.2012.34","url":null,"abstract":"Recommender systems are mechanisms that filter information and predict a user's preference to an item. Parallel implementations of recommender systems improve scalability issues and can be applied to internet-based companies having considerable impact on their profits. This paper implements two parallel versions of the collaborative filtering algorithm Slope One, which has advantages such as its efficiency and the ability to update data dynamically. The first presented version is parallely implemented with the use of the OpenMP API and its performance is evaluated on a multi-core system. The second is an hybrid approach using both OpenMP and MPI and its performance is evaluated in an homogeneous and an heterogeneous cluster. Experiments proved that the multithreaded version is 9,5 times faster than the sequential algorithm.","PeriodicalId":131195,"journal":{"name":"2012 16th Panhellenic Conference on Informatics","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116261912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Gravvanis, C. Filelis-Papadopoulos, E. A. Lipitakis
{"title":"A Note on the Comparison of a Class of Preconditioned Iterative Methods","authors":"G. Gravvanis, C. Filelis-Papadopoulos, E. A. Lipitakis","doi":"10.1109/PCi.2012.12","DOIUrl":"https://doi.org/10.1109/PCi.2012.12","url":null,"abstract":"The preconditioned iterative methods are mainly categorized into implicit preconditioned methods and explicit preconditioned methods. In this manuscript we review implicit preconditioned methods, based on incomplete and approximate factorization, and explicit preconditioned methods, based on sparse approximate inverses and explicit approximate inverses. Additionally we present the modified Moore-Penrose conditions and theoretical estimates on the iteration matrix of the explicit preconditioned method, based on explicit approximate inverses. Finally, the performance of the preconditioned iterative methods is illustrated by solving characteristic 2D elliptic problem and numerical results are given. The theoretical estimates were in qualitative agreement with the numerical results.","PeriodicalId":131195,"journal":{"name":"2012 16th Panhellenic Conference on Informatics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131311857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stelios E. Ploumis, Aggeliki Sgora, Dionisis Kandris, D. Vergados
{"title":"Congestion Avoidance in Wireless Sensor Networks: A Survey","authors":"Stelios E. Ploumis, Aggeliki Sgora, Dionisis Kandris, D. Vergados","doi":"10.1109/PCi.2012.83","DOIUrl":"https://doi.org/10.1109/PCi.2012.83","url":null,"abstract":"Congestion can degrade the performance of a Wireless Sensor Network (WSN) since it causes energy waste, throughput reduction and increased information loss. To prevent this situation several congestion avoidance mechanisms and schemes may be applied. The aim of this paper is to survey existing congestion avoidance mechanisms to classify them and to discuss their advantages and drawbacks.","PeriodicalId":131195,"journal":{"name":"2012 16th Panhellenic Conference on Informatics","volume":"160 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115997235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Secure Management of Medical Data in Wireless Environments","authors":"D. Vassis, P. Belsis, C. Skourlas","doi":"10.1109/PCi.2012.37","DOIUrl":"https://doi.org/10.1109/PCi.2012.37","url":null,"abstract":"Wireless devices are responsible for a new era in computing. New networking paradigms such as mobile computing, ad-hoc networks pervasive infrastructures, all offer new possibilities to the user, from experimental technologies lately some of the aforementioned examples tend to become part of ordinary life applications. The medical sector benefits substantially from the use of mobile devices, since monitoring becomes more efficient and flexible for both the patient as well as for the practitioner. This means that data may be accessible from anywhere, enabling ubiquitous access to information. There are though certain requirements mainly associated with the strict security framework that rules the processing and transmission of medical data. The sensitive nature of medical information forces the implementation of medical wireless systems to be compliant with a number of security related requirements and also to be able to interact with other similar systems (interoperability) as well as to deal with bandwidth and hardware resource constraints that characterize the wireless topology. In this paper we present an architecture that attempts to deal with these issues, moreover, in order to prove the validity of our approach we have also evaluated the performance of our platform through simulation in different operating scenarios.","PeriodicalId":131195,"journal":{"name":"2012 16th Panhellenic Conference on Informatics","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131045938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Christopoulou, Dimitris Ringas, Michail Stefanidakis
{"title":"Experiences from the Urban Computing Impact on Urban Culture","authors":"E. Christopoulou, Dimitris Ringas, Michail Stefanidakis","doi":"10.1109/PCI.2012.53","DOIUrl":"https://doi.org/10.1109/PCI.2012.53","url":null,"abstract":"In this paper we present CLIO an urban computing system used to form and interact with the collective city memory, formed by shared citizens' recollections. Our goal has been to study the impact of such a system on the urban culture and in particular how it alters the city, the perception of people about the city and the communication among people. We applied CLIO and conducted user studies in two different cities, in Greece and Finland, personal memories were collected and context annotated through a storytelling process, people were invited to access CLIO via various interfaces and we observed their reactions browsing collective city memory and their interactions with our system. Our experience shows that urban computing applications can have a strong impact on city culture and people perceive the important role of such applications in the urban life, it is revealed that smartness is a salient aspect of a successful urban computing system.","PeriodicalId":131195,"journal":{"name":"2012 16th Panhellenic Conference on Informatics","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132509645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Voyiatzis, Kyriakos Axiotis, N. Papaspyrou, H. Antonopoulou, C. Efstathiou
{"title":"Test Set Embedding into Low-Power BIST Sequences Using Maximum Bipartite Matching","authors":"I. Voyiatzis, Kyriakos Axiotis, N. Papaspyrou, H. Antonopoulou, C. Efstathiou","doi":"10.1109/PCi.2012.75","DOIUrl":"https://doi.org/10.1109/PCi.2012.75","url":null,"abstract":"Current trends in VLSI designs necessitate low power during both normal system operation and testing activity. Traditional Built-in Self Test (BIST) generators rise unnaturally the power consumption during testing, boosting the need to add low-power solutions to the arsenal of BIST pattern generators. In this paper, the utilization of gray code generators is proposed as a low-power BIST solution. More precisely, we show how the time required to apply a given test pattern can be decreased, by switching between different gray sequences during the application of the test set. Experimental results indicate that the time required to embed the test set within a low-power sequence is reduced to almost 50%, compared to a previously proposed solution.","PeriodicalId":131195,"journal":{"name":"2012 16th Panhellenic Conference on Informatics","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127814380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Tsolkas, N. Passas, C. Xenakis, Vassilis Papataxiarhis, V. Tsetsos
{"title":"Busfinder: A Personalized Multimodal Transportation Guide with Dynamic Routing","authors":"D. Tsolkas, N. Passas, C. Xenakis, Vassilis Papataxiarhis, V. Tsetsos","doi":"10.1109/PCi.2012.19","DOIUrl":"https://doi.org/10.1109/PCi.2012.19","url":null,"abstract":"Multimodal routing services with public transportation are already present in many large cities across the globe. In this paper we describe a mobile guide that goes beyond existing solutions, mainly due to its service personalization and its dynamic routing algorithm. Personalization is based on knowledge engineering principles and Semantic Web technologies. The dynamic routing algorithm is based on short term history and estimators and supports cities with pre-installed fleet management systems in the public transport means.","PeriodicalId":131195,"journal":{"name":"2012 16th Panhellenic Conference on Informatics","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126681944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Maritime Clouds for the European Ports","authors":"Kleanthis Dellios, D. Polemi","doi":"10.1109/PCi.2012.39","DOIUrl":"https://doi.org/10.1109/PCi.2012.39","url":null,"abstract":"The adoption of Cloud Computing technology can lead to a new revolution in the maritime field, offering trustworthy cross-border, interoperable, secure e-port services to all maritime participants. In this paper, cloud technology is introduced in the maritime sector, maritime cloud delivery and deployment models are proposed in order to provide a holistic, harmonized European secure maritime environment.","PeriodicalId":131195,"journal":{"name":"2012 16th Panhellenic Conference on Informatics","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128859971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}