The paper presents a case study of visualization and animation of results of inverse kinematics simulation of a redundant construction manipulator, represented as a mechanical system with four degrees of freedom. The boom consists of four rigid links, interconnected by rotational joints. The rotation of the links is described by relative joint angles and their values, together with the links lengths, determine the manipulator working range. For a prescribed vertical straight-line trajectory, the inverse kinematics task at the velocity level is solved by the use of weighted pseudoinverse matrix. To compensate the deviations from the desired trajectory, the inverse kinematics equation is modified by adding terms, proportional to the difference between the current and the desired position of the boom end point. By the use of the contemporary Web technologies a VR environment for simulation and visualization of the obtained results is developed. It consists of a started under Common Gateway Interface Matlab executable file placed on a server, a Web page with input form, an X3D model of the manipulator. The functionality of the application on the user side is provided by a JavaScript file. The produced VR environment is easy reused and shared with other users and thus considerably facilitates the design, investigation and e-learning of such type of system.
{"title":"Web-based VR Environment for Simulation and Visualization of Construction Manipulator Motion","authors":"B. Tudjarov, Rosen P. Mitrev","doi":"10.1145/3351556.3351562","DOIUrl":"https://doi.org/10.1145/3351556.3351562","url":null,"abstract":"The paper presents a case study of visualization and animation of results of inverse kinematics simulation of a redundant construction manipulator, represented as a mechanical system with four degrees of freedom. The boom consists of four rigid links, interconnected by rotational joints. The rotation of the links is described by relative joint angles and their values, together with the links lengths, determine the manipulator working range. For a prescribed vertical straight-line trajectory, the inverse kinematics task at the velocity level is solved by the use of weighted pseudoinverse matrix. To compensate the deviations from the desired trajectory, the inverse kinematics equation is modified by adding terms, proportional to the difference between the current and the desired position of the boom end point. By the use of the contemporary Web technologies a VR environment for simulation and visualization of the obtained results is developed. It consists of a started under Common Gateway Interface Matlab executable file placed on a server, a Web page with input form, an X3D model of the manipulator. The functionality of the application on the user side is provided by a JavaScript file. The produced VR environment is easy reused and shared with other users and thus considerably facilitates the design, investigation and e-learning of such type of system.","PeriodicalId":126836,"journal":{"name":"Proceedings of the 9th Balkan Conference on Informatics","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125445749","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}
Georgia Koloniari, Georgios Evangelidis, Nikolaos Sachpenderis, Ioannis Milonas
The goal of this paper is to propose a complete framework for addressing the problem of predicting communities behavior in evolving social networks. The framework encompasses all steps required for community detection, analysis and behavior prediction. Our approach is based on modeling community evolution by multidimensional time series that describe the changes of each community's properties, both structural and content-based, through time. The prediction framework is based on rule discovery upon the multidimensional time series, so that based on patterns that appear in the evolution of a community's property so far, future behavior can be predicted. Finally, exploiting the similarity between the behavior of a network's communities, their multidimensional time series will be used for community clustering. Thus, rule discovery can also incorporate global rules that appear in clusters of communities as well as on the network level, so as to discover global behavior patterns that characterize all the communities of a network.
{"title":"A Framework for Predicting Community Behavior in Evolving Social Networks","authors":"Georgia Koloniari, Georgios Evangelidis, Nikolaos Sachpenderis, Ioannis Milonas","doi":"10.1145/3351556.3351583","DOIUrl":"https://doi.org/10.1145/3351556.3351583","url":null,"abstract":"The goal of this paper is to propose a complete framework for addressing the problem of predicting communities behavior in evolving social networks. The framework encompasses all steps required for community detection, analysis and behavior prediction. Our approach is based on modeling community evolution by multidimensional time series that describe the changes of each community's properties, both structural and content-based, through time. The prediction framework is based on rule discovery upon the multidimensional time series, so that based on patterns that appear in the evolution of a community's property so far, future behavior can be predicted. Finally, exploiting the similarity between the behavior of a network's communities, their multidimensional time series will be used for community clustering. Thus, rule discovery can also incorporate global rules that appear in clusters of communities as well as on the network level, so as to discover global behavior patterns that characterize all the communities of a network.","PeriodicalId":126836,"journal":{"name":"Proceedings of the 9th Balkan Conference on Informatics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129026671","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}
Studies have provided evidence that interventions with Socially Assistive Robots (SARs), can help children with Autism Spectrum Disorder (ASD) to develop social skills. This study will outline features of SAR that respond to the heterogeneity of the ASD, thus promote interesting activities in safe environments for children with ASD to feel secure and motivated to participate. Subsequently a research will be presented, that was held with the aim to verify whether a robot can facilitate dyadic activities among children with ASD and TD, more effectively than a human mediator does.
{"title":"Can a robot be an efficient mediator in promoting dyadic activities among children with Autism Spectrum Disorders and children of Typical Development?","authors":"Sofia Pliasa, Nikolaos Fachantidis","doi":"10.1145/3351556.3351592","DOIUrl":"https://doi.org/10.1145/3351556.3351592","url":null,"abstract":"Studies have provided evidence that interventions with Socially Assistive Robots (SARs), can help children with Autism Spectrum Disorder (ASD) to develop social skills. This study will outline features of SAR that respond to the heterogeneity of the ASD, thus promote interesting activities in safe environments for children with ASD to feel secure and motivated to participate. Subsequently a research will be presented, that was held with the aim to verify whether a robot can facilitate dyadic activities among children with ASD and TD, more effectively than a human mediator does.","PeriodicalId":126836,"journal":{"name":"Proceedings of the 9th Balkan Conference on Informatics","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116382234","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}
In nowadays, many users use wireless networks, which are usually based on the IEEE 802.11 standard (Wi-Fi). Because of broadcast technology used, they are easily susceptible to security attacks. It is very important to study the risks and potential vulnerabilities of Wi-Fi networks to recommend users how to improve their security. This paper presents a research of the security of wireless networks in city of Varna, Bulgaria, and methodology based on war-driving technique. The obtained results are summarized and compared with those from previous research. The recommendations for users are formulated.
{"title":"An Empirical Study of Wireless Security in City Environment","authors":"H. Valchanov, J. Edikyan, V. Aleksieva","doi":"10.1145/3351556.3351563","DOIUrl":"https://doi.org/10.1145/3351556.3351563","url":null,"abstract":"In nowadays, many users use wireless networks, which are usually based on the IEEE 802.11 standard (Wi-Fi). Because of broadcast technology used, they are easily susceptible to security attacks. It is very important to study the risks and potential vulnerabilities of Wi-Fi networks to recommend users how to improve their security. This paper presents a research of the security of wireless networks in city of Varna, Bulgaria, and methodology based on war-driving technique. The obtained results are summarized and compared with those from previous research. The recommendations for users are formulated.","PeriodicalId":126836,"journal":{"name":"Proceedings of the 9th Balkan Conference on Informatics","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127436117","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}
The modern portfolio theory applies many computations, needed for assessment of investment policies of financial assets. The optimal portfolio decisions are based on quantitative evaluations, following numerical models and formal relations. Thus, applied computing supports the financial decisions. Without informatics tools and computational environment, such kind of portfolio optimizations is impossible to perform. This paper makes and application of applied computing for the case of estimation and assessing three types of portfolios. They are based on advanced chapters of modern portfolio theory and portfolio optimization. It is provided comparisons between investment policies, which have been developed by mean-variance model and Black-Litterman model with classical and modified formalization of expert views. The applied computations have been performed in MATLAB environment with real data of the Bulgarian Stock Exchange.
{"title":"Applied Computing for Portfolio Optimization in Bulgarian Stock Exchange","authors":"K. Stoilova, T. Stoilov, Miroslav Vladimirov","doi":"10.1145/3351556.3351566","DOIUrl":"https://doi.org/10.1145/3351556.3351566","url":null,"abstract":"The modern portfolio theory applies many computations, needed for assessment of investment policies of financial assets. The optimal portfolio decisions are based on quantitative evaluations, following numerical models and formal relations. Thus, applied computing supports the financial decisions. Without informatics tools and computational environment, such kind of portfolio optimizations is impossible to perform. This paper makes and application of applied computing for the case of estimation and assessing three types of portfolios. They are based on advanced chapters of modern portfolio theory and portfolio optimization. It is provided comparisons between investment policies, which have been developed by mean-variance model and Black-Litterman model with classical and modified formalization of expert views. The applied computations have been performed in MATLAB environment with real data of the Bulgarian Stock Exchange.","PeriodicalId":126836,"journal":{"name":"Proceedings of the 9th Balkan Conference on Informatics","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123482581","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}
In this paper, we investigate the effect of parallelism on two data reduction algorithms that use k-Means clustering in order to find homogeneous clusters in the training set. By homogeneous, we refer to clusters where all instances belong to the same class label. Our approach divides the training set into subsets and applies the data reduction algorithm on each separate subset in parallel. Then, the reduced subsets are merged back to the final reduced set. In our experimental study, we split the datasets into 8, 16, 32 and 64 subsets. The results obtained reveal that parallelism can achieve very low preprocessing costs. Also, when the number of subsets is high, in some datasets the accuracy of k-NN classification is almost equal (if not better) to the one achieved when using the standard execution of the reduction algorithms, with a small loss in the reduction rate.
{"title":"The Effect of Parallelism on Data Reduction","authors":"Pavlos Ponos, Stefanos Ougiaroglou, Georgios Evangelidis","doi":"10.1145/3351556.3351584","DOIUrl":"https://doi.org/10.1145/3351556.3351584","url":null,"abstract":"In this paper, we investigate the effect of parallelism on two data reduction algorithms that use k-Means clustering in order to find homogeneous clusters in the training set. By homogeneous, we refer to clusters where all instances belong to the same class label. Our approach divides the training set into subsets and applies the data reduction algorithm on each separate subset in parallel. Then, the reduced subsets are merged back to the final reduced set. In our experimental study, we split the datasets into 8, 16, 32 and 64 subsets. The results obtained reveal that parallelism can achieve very low preprocessing costs. Also, when the number of subsets is high, in some datasets the accuracy of k-NN classification is almost equal (if not better) to the one achieved when using the standard execution of the reduction algorithms, with a small loss in the reduction rate.","PeriodicalId":126836,"journal":{"name":"Proceedings of the 9th Balkan Conference on Informatics","volume":"14 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125990979","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}
One of the reasons why it is so hard to statically analyze C++ source code is because of its Standard Template Library (STL). The STL is a monstrous collection of complex code base whose semantics is hard for static analyzers to understand. Unfortunately, many of the most serious memory management bugs in C++ are connected to the lifetimes of STL containers. This paper describes a method of adding knowledge of STL ownership semantics to a static analysis engine. It was implemented in an open-source symbolic execution framework widely used in the industry, and produced new and serious lifetime-related error reports in popular open-source projects.
{"title":"Detecting C++ Lifetime Errors with Symbolic Execution","authors":"R. Kovács, G. Horváth, Z. Porkoláb","doi":"10.1145/3351556.3351585","DOIUrl":"https://doi.org/10.1145/3351556.3351585","url":null,"abstract":"One of the reasons why it is so hard to statically analyze C++ source code is because of its Standard Template Library (STL). The STL is a monstrous collection of complex code base whose semantics is hard for static analyzers to understand. Unfortunately, many of the most serious memory management bugs in C++ are connected to the lifetimes of STL containers. This paper describes a method of adding knowledge of STL ownership semantics to a static analysis engine. It was implemented in an open-source symbolic execution framework widely used in the industry, and produced new and serious lifetime-related error reports in popular open-source projects.","PeriodicalId":126836,"journal":{"name":"Proceedings of the 9th Balkan Conference on Informatics","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123001285","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}
V. Yosifova, R. Trifonov, Antoniya Tasheva, Ognian Nakov
The information security problems include a wide range of possible threats that affect almost every aspect of human life. This article makes a survey about the trends of the latest problems in cybersecurity reviewing the security reports issued by some major information security companies. These problems are not static, nor equally distributed. Some of them have more significant impact than others in a specific time but at the next period the situation is changed. The purpose of this paper is to summarize the existing trends in the cyberspace security and to point out the future research tasks in the area.
{"title":"Trends Review of the Contemporary Security Problems in the Cyberspace","authors":"V. Yosifova, R. Trifonov, Antoniya Tasheva, Ognian Nakov","doi":"10.1145/3351556.3351560","DOIUrl":"https://doi.org/10.1145/3351556.3351560","url":null,"abstract":"The information security problems include a wide range of possible threats that affect almost every aspect of human life. This article makes a survey about the trends of the latest problems in cybersecurity reviewing the security reports issued by some major information security companies. These problems are not static, nor equally distributed. Some of them have more significant impact than others in a specific time but at the next period the situation is changed. The purpose of this paper is to summarize the existing trends in the cyberspace security and to point out the future research tasks in the area.","PeriodicalId":126836,"journal":{"name":"Proceedings of the 9th Balkan Conference on Informatics","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115269563","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}
In recent years, Artificial Intelligence (AI) has shown significant progress and its potential is growing. An application area of AI is Natural Language Processing (NLP). Voice assistants incorporate AI using cloud computing and can communicate with the users in natural language. Voice assistants are easy to use and thus there are millions of devices that incorporates them in households nowadays. Most common devices with voice assistants are smart speakers and they have just started to be used in schools and universities. The purpose of this paper is to study the capabilities of voice assistants in the classroom and to present findings from previous studies.
{"title":"Voice Assistants and Artificial Intelligence in Education","authors":"G. Terzopoulos, M. Satratzemi","doi":"10.1145/3351556.3351588","DOIUrl":"https://doi.org/10.1145/3351556.3351588","url":null,"abstract":"In recent years, Artificial Intelligence (AI) has shown significant progress and its potential is growing. An application area of AI is Natural Language Processing (NLP). Voice assistants incorporate AI using cloud computing and can communicate with the users in natural language. Voice assistants are easy to use and thus there are millions of devices that incorporates them in households nowadays. Most common devices with voice assistants are smart speakers and they have just started to be used in schools and universities. The purpose of this paper is to study the capabilities of voice assistants in the classroom and to present findings from previous studies.","PeriodicalId":126836,"journal":{"name":"Proceedings of the 9th Balkan Conference on Informatics","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125326294","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}
While C++ is a powerful language, it has many subtle ways to introduce object lifetime-related errors. According to Microsoft, 70% of their security patches are fixing memory issues. Thus, it is crucial to develop safety measures to counteract these problems. Static analysis is an essential approach to detect runtime errors by analyzing the source code without executing it. One of the reasons why is it so easy to make mistakes using C++ is that the language provides a rich taxonomy of object lifetime-related concepts such as containers, values, iterators, raw pointers, lvalue and rvalue references, smart pointers, etc. The behavior of user-defined types depends on their category. Classical static analysis approaches treat user-defined types as black boxes and do not reason about their correctness. In this paper, we argue for an approach that infers the category of user-defined types and leverages this information during analysis. To achieve this goal we first analyze user-defined classes to predict their ownership semantics. Then we use this information to generalize existing static analysis methods. We evaluated the proposed method on large open source projects.
{"title":"Categorization of C++ Classes for Static Lifetime Analysis","authors":"G. Horváth, Norbert Pataki","doi":"10.1145/3351556.3351559","DOIUrl":"https://doi.org/10.1145/3351556.3351559","url":null,"abstract":"While C++ is a powerful language, it has many subtle ways to introduce object lifetime-related errors. According to Microsoft, 70% of their security patches are fixing memory issues. Thus, it is crucial to develop safety measures to counteract these problems. Static analysis is an essential approach to detect runtime errors by analyzing the source code without executing it. One of the reasons why is it so easy to make mistakes using C++ is that the language provides a rich taxonomy of object lifetime-related concepts such as containers, values, iterators, raw pointers, lvalue and rvalue references, smart pointers, etc. The behavior of user-defined types depends on their category. Classical static analysis approaches treat user-defined types as black boxes and do not reason about their correctness. In this paper, we argue for an approach that infers the category of user-defined types and leverages this information during analysis. To achieve this goal we first analyze user-defined classes to predict their ownership semantics. Then we use this information to generalize existing static analysis methods. We evaluated the proposed method on large open source projects.","PeriodicalId":126836,"journal":{"name":"Proceedings of the 9th Balkan Conference on Informatics","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114456869","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：