This special issue of the Journal of Networks includes mainly extended versions of selected paper... more This special issue of the Journal of Networks includes mainly extended versions of selected papers accepted and presented at the 2009 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS 2009). Only papers with excellent review scores were invited to submit extended versions to this Special Issue, which have undergone a second review process. The selected papers address a variety of topics related to the performance evaluation of communication networks and systems. In the first paper, "Analysis of a Buffered Optical Switch with General Interarrival Times", by Conor McArdle, Daniele Tafani and Liam P. Barry, the authors developed a relatively simple model for the analysis of an OBS (Optical Burst Switching) node with FDLs (Fiber Delay Lines) by applying circuit switching analysis methods. The model may be used to evaluate performance under any general independent (GI) traffic stream that may be expressed in terms of the LST (Laplace-Stieltjes transform) of the interarrival distribution. The analysis is formulated in terms of virtual traffic flows within the optical switch from which expressions for burst blocking probability, fiber delay line occupancy and mean delay are derived. The second paper, "Comparison of the Design Characteristics of MMI Wavelength Demultiplexers Using Different Approaches by Computing the Effective Index", authored by M. Najjar, R. Rejeb, H. Rezig and M. S. Obaidat, investigates the design characteristics of a wavelength demultiplexer using the effective index method in order to determine the propagation constants and field distributions. In order to analyze the impact of computation method on the design characteristics of the demultiplexer, the effective index is computed by an analytic approach. A new algorithm for developing an analytic model is proposed.
Six papers were selected based on their excellent review scores. Their authors were invited to su... more Six papers were selected based on their excellent review scores. Their authors were invited to submit extended versions which have undergone a second review process. This selection addresses a variety of topics related to the Performance Modeling and Evaluation of Computer and Telecommunication Systems.
In this paper we present a set of tools that help in building interfaces for users who exhibit un... more In this paper we present a set of tools that help in building interfaces for users who exhibit uncontrolled tremor in their upper limbs. These tools, which use a standard sketch board as sensing and final interface device, permit the logging of movement information while the user performs some simple tasks. Several movement analysis tests are proposed and applied to a small group of users. These preliminary experiments were conducted as a phenomenological study of these users. Although the sample size is small, test results are studied in detail and several important conclusions are obtained. Furthermore, useful data and procedures for building usable interfaces are also presented.
The use of simulation tools in the development of new Wireless Sensor Networks protocols and appl... more The use of simulation tools in the development of new Wireless Sensor Networks protocols and applications should be accompanied by minimisation of redundant code and work, making it possible to seamlessly run the same code on simulated and real platforms. This work proposes an architecture for a WSN testing platform that integrates simulation tools in an application-transparent way. The platform will be focused on testing the WSN sink node and providing it with both real and simulated data. The novelty of this approach lies in the use of a flexible network simulation tool not focused on a specific network technology, and the use of generic hardware and open source tools.
International Symposium on Performance Evaluation of Computer and Telecommunication Systems, Jul 13, 2009
Address event representation (AER) is a neuromorphic interchip communication protocol that allows... more Address event representation (AER) is a neuromorphic interchip communication protocol that allows for real-time virtual massive connectivity between huge number neurons located on different chips. When building multichip mutilayered AER systems it is absolutely necessary to have a computer interface that allows (a) to read AER interchip traffic into the computer and visualize it on screen, and (b) convert conventional
International Journal of Communication Systems, Aug 15, 2013
Currently, wireless sensor networks (WSNs) are formed by devices with limited resources and limit... more Currently, wireless sensor networks (WSNs) are formed by devices with limited resources and limited power energy availability. Thanks to their cost effectiveness, flexibility, and ease of deployment, wireless sensor networks have been applied to many scenarios such as industrial, civil, and military applications. For many applications, security is a primary issue, but this produces an extra energy cost. Thus, in real applications, a trade-off is required between the security level and energy consumption. This paper evaluates different security schemes applied to human tracking applications, based on a real-case scenario.
Ns-2 and its successor ns-3 are discrete-event simulators. Ns-3 is still under development, but o... more Ns-2 and its successor ns-3 are discrete-event simulators. Ns-3 is still under development, but offers some interesting characteristics for developers while ns-2 still has a big user base. This paper remarks current differences between both tools from developers point of view. Leaving performance and resources consumption aside, technical issues described in the present paper might help to choose one or another alternative depending of simulation and project management requirements.
Image processing in digital computer systems usually considers the visual information as a sequen... more Image processing in digital computer systems usually considers the visual information as a sequence of frames. These frames are from cameras that capture reality for a short period of time. They are renewed and transmitted at a rate of 25-30 frames per second, in a typical real-time scenario. Digital video processing has to process each frame in order to obtain a filter result or detect a feature on the input. This processing is usually based on very complex and expensive (in resources) operations for an efficient real-time application. Brain can perform very complex visual processing in real-time using relatively simple cells, called neurons, which codify the information into spikes. Spike-based processing is a relatively new approach that implements the processing by manipulating spikes one by one at the time they are transmitted, like a human brain. The spike-based philosophy for visual information processing based on the neuro-inspired Address Event Representation (AER) is achieving nowadays very high performances. In this work we study the low level performance for realtime scenarios of a spike-based co-processor connected to a conventional PC and implemented through a PCI board. These low level lacks are focused both in the software conversion of static frames into AER format and in the bottleneck of the PCI interface.
... Wibree16 is a Nokia proposal for WSN using Bluetooth PHY layer and simplifying upper layers t... more ... Wibree16 is a Nokia proposal for WSN using Bluetooth PHY layer and simplifying upper layers to guarantee very low power consumption. Wibree allows total compatibility with traditional Bluetooth devices at similar data rates (than 1.0 specification) but at very low power ...
Simulation Modelling Practice and Theory, May 1, 2011
Ns-2 and its successor ns-3 are discrete-event simulators which are closely related to each other... more Ns-2 and its successor ns-3 are discrete-event simulators which are closely related to each other as they share common background, concepts and similar aims. Ns-3 is still under development, but it offers some interesting characteristics for developers while ns-2 still has a large user base. While other studies have compared different network simulators, focusing on performance measurements, in this paper we adopted a different approach by focusing on technical characteristics and using software metrics to obtain useful conclusions. We chose ns-2 and ns-3 for our case study because of the popularity of the former in research and the increasing use of the latter. This reflects the current situation where ns-3 has emerged as a viable alternative to ns-2 due to its features and design. The paper assesses the current state of both projects and their respective evolution supported by the measurements obtained from a broad set of software metrics. By considering other qualitative characteristics we obtained a summary of technical features of both simulators including, architectural design, software dependencies or documentation policies. 1. Introduction Simulation is a key tool in networking research due to its inherent advantages over testing with real hardware [1]. Matters such as budget and cost of time make simulation attractive for research, while flexibility, scalability and virtually no cost expansion are also valuable advantages over other testing methods [2]. Network simulators allow us to implement and study different network entities in a simulated environment, providing a high degree of flexibility to test new protocols, technologies, conceptual models and topologies. Ns-3 [3] has been conceived as ns-2's successor: its developers have tried to solve or mitigate many of ns-2's well-known drawbacks as well as apply new concepts, such as validation and software engineering techniques, to produce a more reliable simulation tool to support academic and industrial research [4]. Other technical papers have already compared ns-2 and ns-3 [5], along with other network simulators, evaluating their core performance and scheduling capabilities but not focusing on any specific simulator features to make the comparison of very different pieces of software as fair as possible. Instead this study has focused on two specific simulators, ns-2 and ns-3, which are quite close in terms of structure, aims and user base. These facts allowed us to focus on technical aspects that are not directly comparable in other simulation packages due to their quite different characteristics and nature. In other words, adding other simulator packages to this study would introduce too different elements that are not susceptible to be compared in the same terms than with ns-2 and ns-3. One good reference that has good review of other simulation packages that the interested reader may want to look at is Obaidat and Papadimitriou [6].
Address Event Representation (AER) is a that are more active are accessing the bus more frequentl... more Address Event Representation (AER) is a that are more active are accessing the bus more frequently neuromorphic interchip communication protocol that allows than those less active. for real-time connectivity between huge number neurons located on different chips. By exploiting high speed digital CPIE2 communication circuits (nano-seconds), synaptic neural 1111|111SI In connections can be time multiplexed (mili-seconds). When wIFAL building multi-chip muti-layered AER systems it is absolutely
Intimate partner violence against women (IPVW) is a pressing social issue which poses a challenge... more Intimate partner violence against women (IPVW) is a pressing social issue which poses a challenge in terms of prevention, legal action, and reporting the abuse once it has occurred. However, a significant number of female victims who file a complaint against their abuser and initiate legal proceedings, subsequently, withdraw charges for different reasons. Research in this field has been focusing on identifying the factors underlying women victims' decision to disengage from the legal process to enable intervention before this occurs. Previous studies have applied statistical models to use input variables and make a prediction of withdrawal. However, none have used machine learning models to predict disengagement from legal proceedings in IPVW cases. This could represent a more accurate way of detecting these events. This study applied machine learning (ML) techniques to predict the decision of IPVW victims to withdraw from prosecution. Three different ML algorithms were optimized and tested with the original dataset to assess the performance of ML models against non-linear input data. Once the best models had been obtained, explainable artificial intelligence (xAI) techniques were applied to search for the most informative input features and reduce the original dataset to the most important variables. Finally, these results were compared to those obtained in the previous work that used statistical techniques, and the set of most informative parameters was combined with the variables of the previous study, showing that ML-based models had a better predictive accuracy in all cases and that by adding one new variable to the previous work's predictive model, the accuracy to detect withdrawal improved by 7.5%.
Diavideos is a web platform that collects trustworthy diabetes health videos from YouTube and off... more Diavideos is a web platform that collects trustworthy diabetes health videos from YouTube and offers them in a easy way. YouTube is a big repository of health videos, but good content is sometimes mixed with misleading and harmful videos such as promoting anorexia [1]. Diavideos is a web portal that provides easy access to a repository of trustworthy diabetes videos. This poster describes Diavideos and explains the crawling method used to retrieve these videos from trusted channels.
Guest Editorial This special issue of the Journal of Networks includes extended versions of exten... more Guest Editorial This special issue of the Journal of Networks includes extended versions of extended versions of selected best papers accepted and presented at the 8th International Joint Conference on e-Business and Telecommunications (ICETE 2011). Eight papers were selected based on their excellent review scores. Their authors were invited to submit extended versions, which have undergone a second review process to guarantee that all the papers included in this Special Issue have been rigorously peer-reviewed. The accepted papers cover areas like empirical evaluations, simulation modeling and theoretical studies addressing a variety of topics related to security in telecommunications, wireless networking, and localization. The first paper "Simplified Scheduling for Underwater Acoustic Networks" is authored by W. Van Kleunen, N. Meratnia and P. J. M. Havinga. It proposes an interesting solution to the scheduling and routing issues in underwater acoustic networks, giving a simplified set of constrains. These constrains are applied to three new scheduling algorithms: centralized for maximum throughput, distributed for low computational costs and centralized for low-latency end-toend communications. The evaluation by simulation explores extensively the benefits obtained when the new set of constrains is applied to the proposed algorithms. The second paper, entitled "Power Management Mechanism Exploiting Network and Video Information over Wireless Links" authored by C. Bouras, S. Charalambides, K. Stamos, S. Stroumpis and G. Zaoudis, describes some cross-layer mechanisms to manage power consumption in wireless communications. The authors focus their analysis on video transmissions. The scenarios proposed are simulated using ns-2 simulator, obtaining relevant results referred to the video quality and the associated power consumption. In the third paper, "QoS-Aware Multipath Communications over MANETs", by M. Obaidat, M. Ali, I. Shahwan, M. S. Obaidat, and S. Obeidat, the authors propose a QoS aware routing protocol based on multipath routing. They try to minimize the packet delay providing more than one path between source and destination, and choosing the best path based on the quality of the link. The new protocol is compared against another well-known single path routing protocol (AODV) by means of simulation over OPNET. The results show that the new routing protocol outperforms AODV in terms of end-to-end delay, but at the cost of a greater protocol overhead. The fourth paper, "Fingerprint Indoor Position System Based On Bitcloud and Openmac", authored by J. A. Gómez, A. V. Medina, E. Dorronzoro, O. Rivera and M. Merino, uses fingerprints as an alternative approach to estimate location of mobile nodes in WSNs. The fingerprints are used in two algorithms, being the second one (centroid) the algorithm that offers more accuracy. The algorithms are tested in two real implementations (bitcloud and openmac) over a specific scenario. The results show that openmac can overtake the problems detected in bitcloud and improve the precision on localization. The fifth paper is entitled "Localization Method For Low Power Wireless Sensor Networks", authored by D. F. Larios, J. Barbancho, F. J. Molina and C. León. This paper proposes a range-free localization algorithm that uses fuzzy logic to process RSSI and estimate the position of mobile devices. This method causes less localization errors than other well-known localization methods and, at the same time, it improves power consumption of the mobile nodes. The sixth paper, "Development Tools For Context Aware And Secure Pervasive Computing in Embedded Systems (PECES) Middleware", authored by R. Zhao, K. Selvarajah and N. Speirs presents a set of tools to enable the communication among heterogeneous devices across multiple smart devices and platforms in a secure manner. PECES and its tools are especially useful for experienced developers of services and applications that desire a clean deployment of their applications regardless of the platform for which they are developing. PECES has been evaluated by means of heuristic techniques that conclude that the majority of interviewed people assert that PECES is useful, and easy to use. The seventh paper "Performance of OpenDPI in Identifying Sampled Network Traffic", authored by J. Khalife, A. Hajjar and J. Diaz, studies the impact of sampling traffic on the performance of OpenDPI, by means of two different ways of gathering information: per-packet sampling and per-flow sampling, in order to determine the reduction of the input data and the accuracy of the classification. Results show that the per-flow packet is more convenient for sampling; showing very high accuracy rates. The last paper entitled, "Anomaly Detection Using Metaheuristic Firefly Harmonic Clustering", authored by M. H. A. C. Adaniya, T. Abrão and M. Lemes Proença presents a clustering algorithm based on K-Harmonic means (KHM) and Firefly Algorithm (FA) for the detection of network volume anomalies due to device failing or misconfiguration. As a consequence of the application to the real data collected from a proxy server, and a further statistic analysis, the algorithm achieves about 80% of true positive recognitions and 20% of false positive recognitions, demonstrating the satisfactory behaviour of this algorithm. The guest editors would like to thank all the authors and reviewers for their valuable contributions to this special issue. We also thank the editorial staff of Journal of Networking for their support. We hope that the papers selected in this special issue will become useful resources for researchers and practitioners in these areas.
International Symposium on Performance Evaluation of Computer and Telecommunication Systems, Jul 8, 2012
ABSTRACT Several works in the literature have recently addressed the study of different Networked... more ABSTRACT Several works in the literature have recently addressed the study of different Networked Virtual Environments (NVE) due to their increasing popularity and widespread use in fields ranging from entertainment to e-Health. Open Wonderland is one of these NVEs which has been the subject of several studies mainly focused on the client side. This paper aims to cover the server-side performance issues to provide complementary results that can be useful for properly sizing Open Wonderland systems according to the number of expected users. An experimental testbed is used, which provides real data that shows that CPU and outgoing bandwidth are the most critical parameters when the number of clients increase.
This special issue of the Journal of Networks includes mainly extended versions of selected paper... more This special issue of the Journal of Networks includes mainly extended versions of selected papers accepted and presented at the 2009 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS 2009). Only papers with excellent review scores were invited to submit extended versions to this Special Issue, which have undergone a second review process. The selected papers address a variety of topics related to the performance evaluation of communication networks and systems. In the first paper, "Analysis of a Buffered Optical Switch with General Interarrival Times", by Conor McArdle, Daniele Tafani and Liam P. Barry, the authors developed a relatively simple model for the analysis of an OBS (Optical Burst Switching) node with FDLs (Fiber Delay Lines) by applying circuit switching analysis methods. The model may be used to evaluate performance under any general independent (GI) traffic stream that may be expressed in terms of the LST (Laplace-Stieltjes transform) of the interarrival distribution. The analysis is formulated in terms of virtual traffic flows within the optical switch from which expressions for burst blocking probability, fiber delay line occupancy and mean delay are derived. The second paper, "Comparison of the Design Characteristics of MMI Wavelength Demultiplexers Using Different Approaches by Computing the Effective Index", authored by M. Najjar, R. Rejeb, H. Rezig and M. S. Obaidat, investigates the design characteristics of a wavelength demultiplexer using the effective index method in order to determine the propagation constants and field distributions. In order to analyze the impact of computation method on the design characteristics of the demultiplexer, the effective index is computed by an analytic approach. A new algorithm for developing an analytic model is proposed.
Six papers were selected based on their excellent review scores. Their authors were invited to su... more Six papers were selected based on their excellent review scores. Their authors were invited to submit extended versions which have undergone a second review process. This selection addresses a variety of topics related to the Performance Modeling and Evaluation of Computer and Telecommunication Systems.
In this paper we present a set of tools that help in building interfaces for users who exhibit un... more In this paper we present a set of tools that help in building interfaces for users who exhibit uncontrolled tremor in their upper limbs. These tools, which use a standard sketch board as sensing and final interface device, permit the logging of movement information while the user performs some simple tasks. Several movement analysis tests are proposed and applied to a small group of users. These preliminary experiments were conducted as a phenomenological study of these users. Although the sample size is small, test results are studied in detail and several important conclusions are obtained. Furthermore, useful data and procedures for building usable interfaces are also presented.
The use of simulation tools in the development of new Wireless Sensor Networks protocols and appl... more The use of simulation tools in the development of new Wireless Sensor Networks protocols and applications should be accompanied by minimisation of redundant code and work, making it possible to seamlessly run the same code on simulated and real platforms. This work proposes an architecture for a WSN testing platform that integrates simulation tools in an application-transparent way. The platform will be focused on testing the WSN sink node and providing it with both real and simulated data. The novelty of this approach lies in the use of a flexible network simulation tool not focused on a specific network technology, and the use of generic hardware and open source tools.
International Symposium on Performance Evaluation of Computer and Telecommunication Systems, Jul 13, 2009
Address event representation (AER) is a neuromorphic interchip communication protocol that allows... more Address event representation (AER) is a neuromorphic interchip communication protocol that allows for real-time virtual massive connectivity between huge number neurons located on different chips. When building multichip mutilayered AER systems it is absolutely necessary to have a computer interface that allows (a) to read AER interchip traffic into the computer and visualize it on screen, and (b) convert conventional
International Journal of Communication Systems, Aug 15, 2013
Currently, wireless sensor networks (WSNs) are formed by devices with limited resources and limit... more Currently, wireless sensor networks (WSNs) are formed by devices with limited resources and limited power energy availability. Thanks to their cost effectiveness, flexibility, and ease of deployment, wireless sensor networks have been applied to many scenarios such as industrial, civil, and military applications. For many applications, security is a primary issue, but this produces an extra energy cost. Thus, in real applications, a trade-off is required between the security level and energy consumption. This paper evaluates different security schemes applied to human tracking applications, based on a real-case scenario.
Ns-2 and its successor ns-3 are discrete-event simulators. Ns-3 is still under development, but o... more Ns-2 and its successor ns-3 are discrete-event simulators. Ns-3 is still under development, but offers some interesting characteristics for developers while ns-2 still has a big user base. This paper remarks current differences between both tools from developers point of view. Leaving performance and resources consumption aside, technical issues described in the present paper might help to choose one or another alternative depending of simulation and project management requirements.
Image processing in digital computer systems usually considers the visual information as a sequen... more Image processing in digital computer systems usually considers the visual information as a sequence of frames. These frames are from cameras that capture reality for a short period of time. They are renewed and transmitted at a rate of 25-30 frames per second, in a typical real-time scenario. Digital video processing has to process each frame in order to obtain a filter result or detect a feature on the input. This processing is usually based on very complex and expensive (in resources) operations for an efficient real-time application. Brain can perform very complex visual processing in real-time using relatively simple cells, called neurons, which codify the information into spikes. Spike-based processing is a relatively new approach that implements the processing by manipulating spikes one by one at the time they are transmitted, like a human brain. The spike-based philosophy for visual information processing based on the neuro-inspired Address Event Representation (AER) is achieving nowadays very high performances. In this work we study the low level performance for realtime scenarios of a spike-based co-processor connected to a conventional PC and implemented through a PCI board. These low level lacks are focused both in the software conversion of static frames into AER format and in the bottleneck of the PCI interface.
... Wibree16 is a Nokia proposal for WSN using Bluetooth PHY layer and simplifying upper layers t... more ... Wibree16 is a Nokia proposal for WSN using Bluetooth PHY layer and simplifying upper layers to guarantee very low power consumption. Wibree allows total compatibility with traditional Bluetooth devices at similar data rates (than 1.0 specification) but at very low power ...
Simulation Modelling Practice and Theory, May 1, 2011
Ns-2 and its successor ns-3 are discrete-event simulators which are closely related to each other... more Ns-2 and its successor ns-3 are discrete-event simulators which are closely related to each other as they share common background, concepts and similar aims. Ns-3 is still under development, but it offers some interesting characteristics for developers while ns-2 still has a large user base. While other studies have compared different network simulators, focusing on performance measurements, in this paper we adopted a different approach by focusing on technical characteristics and using software metrics to obtain useful conclusions. We chose ns-2 and ns-3 for our case study because of the popularity of the former in research and the increasing use of the latter. This reflects the current situation where ns-3 has emerged as a viable alternative to ns-2 due to its features and design. The paper assesses the current state of both projects and their respective evolution supported by the measurements obtained from a broad set of software metrics. By considering other qualitative characteristics we obtained a summary of technical features of both simulators including, architectural design, software dependencies or documentation policies. 1. Introduction Simulation is a key tool in networking research due to its inherent advantages over testing with real hardware [1]. Matters such as budget and cost of time make simulation attractive for research, while flexibility, scalability and virtually no cost expansion are also valuable advantages over other testing methods [2]. Network simulators allow us to implement and study different network entities in a simulated environment, providing a high degree of flexibility to test new protocols, technologies, conceptual models and topologies. Ns-3 [3] has been conceived as ns-2's successor: its developers have tried to solve or mitigate many of ns-2's well-known drawbacks as well as apply new concepts, such as validation and software engineering techniques, to produce a more reliable simulation tool to support academic and industrial research [4]. Other technical papers have already compared ns-2 and ns-3 [5], along with other network simulators, evaluating their core performance and scheduling capabilities but not focusing on any specific simulator features to make the comparison of very different pieces of software as fair as possible. Instead this study has focused on two specific simulators, ns-2 and ns-3, which are quite close in terms of structure, aims and user base. These facts allowed us to focus on technical aspects that are not directly comparable in other simulation packages due to their quite different characteristics and nature. In other words, adding other simulator packages to this study would introduce too different elements that are not susceptible to be compared in the same terms than with ns-2 and ns-3. One good reference that has good review of other simulation packages that the interested reader may want to look at is Obaidat and Papadimitriou [6].
Address Event Representation (AER) is a that are more active are accessing the bus more frequentl... more Address Event Representation (AER) is a that are more active are accessing the bus more frequently neuromorphic interchip communication protocol that allows than those less active. for real-time connectivity between huge number neurons located on different chips. By exploiting high speed digital CPIE2 communication circuits (nano-seconds), synaptic neural 1111|111SI In connections can be time multiplexed (mili-seconds). When wIFAL building multi-chip muti-layered AER systems it is absolutely
Intimate partner violence against women (IPVW) is a pressing social issue which poses a challenge... more Intimate partner violence against women (IPVW) is a pressing social issue which poses a challenge in terms of prevention, legal action, and reporting the abuse once it has occurred. However, a significant number of female victims who file a complaint against their abuser and initiate legal proceedings, subsequently, withdraw charges for different reasons. Research in this field has been focusing on identifying the factors underlying women victims' decision to disengage from the legal process to enable intervention before this occurs. Previous studies have applied statistical models to use input variables and make a prediction of withdrawal. However, none have used machine learning models to predict disengagement from legal proceedings in IPVW cases. This could represent a more accurate way of detecting these events. This study applied machine learning (ML) techniques to predict the decision of IPVW victims to withdraw from prosecution. Three different ML algorithms were optimized and tested with the original dataset to assess the performance of ML models against non-linear input data. Once the best models had been obtained, explainable artificial intelligence (xAI) techniques were applied to search for the most informative input features and reduce the original dataset to the most important variables. Finally, these results were compared to those obtained in the previous work that used statistical techniques, and the set of most informative parameters was combined with the variables of the previous study, showing that ML-based models had a better predictive accuracy in all cases and that by adding one new variable to the previous work's predictive model, the accuracy to detect withdrawal improved by 7.5%.
Diavideos is a web platform that collects trustworthy diabetes health videos from YouTube and off... more Diavideos is a web platform that collects trustworthy diabetes health videos from YouTube and offers them in a easy way. YouTube is a big repository of health videos, but good content is sometimes mixed with misleading and harmful videos such as promoting anorexia [1]. Diavideos is a web portal that provides easy access to a repository of trustworthy diabetes videos. This poster describes Diavideos and explains the crawling method used to retrieve these videos from trusted channels.
Guest Editorial This special issue of the Journal of Networks includes extended versions of exten... more Guest Editorial This special issue of the Journal of Networks includes extended versions of extended versions of selected best papers accepted and presented at the 8th International Joint Conference on e-Business and Telecommunications (ICETE 2011). Eight papers were selected based on their excellent review scores. Their authors were invited to submit extended versions, which have undergone a second review process to guarantee that all the papers included in this Special Issue have been rigorously peer-reviewed. The accepted papers cover areas like empirical evaluations, simulation modeling and theoretical studies addressing a variety of topics related to security in telecommunications, wireless networking, and localization. The first paper "Simplified Scheduling for Underwater Acoustic Networks" is authored by W. Van Kleunen, N. Meratnia and P. J. M. Havinga. It proposes an interesting solution to the scheduling and routing issues in underwater acoustic networks, giving a simplified set of constrains. These constrains are applied to three new scheduling algorithms: centralized for maximum throughput, distributed for low computational costs and centralized for low-latency end-toend communications. The evaluation by simulation explores extensively the benefits obtained when the new set of constrains is applied to the proposed algorithms. The second paper, entitled "Power Management Mechanism Exploiting Network and Video Information over Wireless Links" authored by C. Bouras, S. Charalambides, K. Stamos, S. Stroumpis and G. Zaoudis, describes some cross-layer mechanisms to manage power consumption in wireless communications. The authors focus their analysis on video transmissions. The scenarios proposed are simulated using ns-2 simulator, obtaining relevant results referred to the video quality and the associated power consumption. In the third paper, "QoS-Aware Multipath Communications over MANETs", by M. Obaidat, M. Ali, I. Shahwan, M. S. Obaidat, and S. Obeidat, the authors propose a QoS aware routing protocol based on multipath routing. They try to minimize the packet delay providing more than one path between source and destination, and choosing the best path based on the quality of the link. The new protocol is compared against another well-known single path routing protocol (AODV) by means of simulation over OPNET. The results show that the new routing protocol outperforms AODV in terms of end-to-end delay, but at the cost of a greater protocol overhead. The fourth paper, "Fingerprint Indoor Position System Based On Bitcloud and Openmac", authored by J. A. Gómez, A. V. Medina, E. Dorronzoro, O. Rivera and M. Merino, uses fingerprints as an alternative approach to estimate location of mobile nodes in WSNs. The fingerprints are used in two algorithms, being the second one (centroid) the algorithm that offers more accuracy. The algorithms are tested in two real implementations (bitcloud and openmac) over a specific scenario. The results show that openmac can overtake the problems detected in bitcloud and improve the precision on localization. The fifth paper is entitled "Localization Method For Low Power Wireless Sensor Networks", authored by D. F. Larios, J. Barbancho, F. J. Molina and C. León. This paper proposes a range-free localization algorithm that uses fuzzy logic to process RSSI and estimate the position of mobile devices. This method causes less localization errors than other well-known localization methods and, at the same time, it improves power consumption of the mobile nodes. The sixth paper, "Development Tools For Context Aware And Secure Pervasive Computing in Embedded Systems (PECES) Middleware", authored by R. Zhao, K. Selvarajah and N. Speirs presents a set of tools to enable the communication among heterogeneous devices across multiple smart devices and platforms in a secure manner. PECES and its tools are especially useful for experienced developers of services and applications that desire a clean deployment of their applications regardless of the platform for which they are developing. PECES has been evaluated by means of heuristic techniques that conclude that the majority of interviewed people assert that PECES is useful, and easy to use. The seventh paper "Performance of OpenDPI in Identifying Sampled Network Traffic", authored by J. Khalife, A. Hajjar and J. Diaz, studies the impact of sampling traffic on the performance of OpenDPI, by means of two different ways of gathering information: per-packet sampling and per-flow sampling, in order to determine the reduction of the input data and the accuracy of the classification. Results show that the per-flow packet is more convenient for sampling; showing very high accuracy rates. The last paper entitled, "Anomaly Detection Using Metaheuristic Firefly Harmonic Clustering", authored by M. H. A. C. Adaniya, T. Abrão and M. Lemes Proença presents a clustering algorithm based on K-Harmonic means (KHM) and Firefly Algorithm (FA) for the detection of network volume anomalies due to device failing or misconfiguration. As a consequence of the application to the real data collected from a proxy server, and a further statistic analysis, the algorithm achieves about 80% of true positive recognitions and 20% of false positive recognitions, demonstrating the satisfactory behaviour of this algorithm. The guest editors would like to thank all the authors and reviewers for their valuable contributions to this special issue. We also thank the editorial staff of Journal of Networking for their support. We hope that the papers selected in this special issue will become useful resources for researchers and practitioners in these areas.
International Symposium on Performance Evaluation of Computer and Telecommunication Systems, Jul 8, 2012
ABSTRACT Several works in the literature have recently addressed the study of different Networked... more ABSTRACT Several works in the literature have recently addressed the study of different Networked Virtual Environments (NVE) due to their increasing popularity and widespread use in fields ranging from entertainment to e-Health. Open Wonderland is one of these NVEs which has been the subject of several studies mainly focused on the client side. This paper aims to cover the server-side performance issues to provide complementary results that can be useful for properly sizing Open Wonderland systems according to the number of expected users. An experimental testbed is used, which provides real data that shows that CPU and outgoing bandwidth are the most critical parameters when the number of clients increase.
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Papers by Jose Sevillano