One of the main challenges in Wireless sensor network (WSN) is the connectivity and coverage. Con... more One of the main challenges in Wireless sensor network (WSN) is the connectivity and coverage. Connectivity is responsible of keeping the different nodes in the network connected and exchange data. Coverage impacts how efficient we are utilizing the operating sensors or mobile devices in the network. To provide a better performance to the connectivity in the network, one of the solutions is to maximize the coverage. This paper provides a novel resilient incremental algorithm which improves the coverage of connected mobile devices within a heterogeneous and homogeneous networks. Extensive simulations showed an improvement on the coverage up to 99% in homogeneous environments and 89% in heterogeneous environments.
The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.
International Journal of Distributed Sensor Networks, Feb 1, 2019
The failure of communications systems may cause catastrophic damage to human life and economic ac... more The failure of communications systems may cause catastrophic damage to human life and economic activities as people are unable to communicate with each other in a timely manner and with a convenient quality of service. Therefore, the exchange of information is more than necessary for people in their everyday life or during harsh environments to prevent the death and injury of thousands of individuals. The study of communications systems behavior in harsh environments helps to design or select more resilient technologies that are capable of operating in challenging conditions. This article reviews existing approaches, major causes of failure, and weaknesses of communications systems during extreme events. First, we highlight the importance of communications systems, and then we examine related works, how communication may fail, and the effect of this failure on human life in general and during extreme events response. Furthermore, we study and analyze how communications are used during various stages of extreme events, and we identify the main weaknesses and limitations that communications systems may suffer based on many case studies. To conclude, we identify and discuss relevant attributes, requirements, and recommendations for communications systems to perform with a suitable quality of service during harsh environments and to reduce risks of communication failure in challenging conditions.
HealthCare system is considered a key element in ubiquitous computing, which means health care se... more HealthCare system is considered a key element in ubiquitous computing, which means health care services are recommended at any time and at any places to monitor patients based on their context. This study aims to define a simple framework that could be guidelines when you start thinking about building a health context-awareness system in ubiquitous environment. This paper starts by defining the concept of context and then presenting a comprehensive list of context models. Outcome of the work of this research is an ontology healthcare model based on current context of patient which makes monitoring process more accurate. This study includes an Android application in order to prove the concept of this hypothesis.
This paper describes ubiquitous computing and context-aware applications. It presents briefly a s... more This paper describes ubiquitous computing and context-aware applications. It presents briefly a survey and contributions of our works and many others works done during the last years.
The separation of concerns as a conceptual paradigm, aims to manage the complexity of the softwar... more The separation of concerns as a conceptual paradigm, aims to manage the complexity of the software systems by dividing them into different concerns and aspects. The benefits of this paradigm such as adaptability, reuse and maintenance, have been key drivers of its adoption and usability. These quality attributes have been discussed in aspect-oriented programming (AOP) which is a complement to traditional programming methods, whether object-oriented programming or procedural programming. The main concept of AOP is to gather the treatments related to a specific concern (problem) in a centralized unit called aspect. In this paper, two case studies of AOP are conducted with AspectJ: i) through three different implementations, addressing three distinct issues: Logging, Adding features and Using the Observer design pattern, and ii) through the design of aspect mobile application that is easy to use and quickly accessible and especially through Android devices. Also, the different technologies of AspectJ are used to design our application and illustrate the modularity and the composition of components (database manager, development software, and plugins). For each case study, we present the advantages and disadvantages to better understand and decompose the applications using this programming paradigm. Potential implementation examples are provided to support the explanation of the different situations and justify the use of the AOP to solve these issues. OSGi framework can also be used in the future work to offer dynamic manner of mobile applications.
Recommendation technique is a personalized search used to assist a user access information/servic... more Recommendation technique is a personalized search used to assist a user access information/services that are related to his preferences and interests, or to the preferences and interests of similar users. The main challenge of personalized Information Retrieval is the modeling and the integration of user profiles. In this paper, we propose a generic model of user profiles based on the search history of users delimited by several search sessions. These profiles are based on weighted topical graphs and are integrated into a hybrid data recommendation process. To evaluate the proposed system a prototype is developed. The results are quite encouraging; they showed that our model is able to help users when searching for items.
The study of radio signal propagation path loss (PL) is important for planning, designing and eva... more The study of radio signal propagation path loss (PL) is important for planning, designing and evaluating the performance of radio communication networks. However, the state-of-the-art in PL modelling for fixed wireless networks in rural environments is still ill-equipped for making accurate predictions. This paper explores the application of the log distance PL model to heterogeneous fixed wireless networks in harsh rural propagation conditions. This model is then extended and optimized to improve its accuracy. In particular, the dataset is classified according to many criteria, radio links are split into many intervals according to their distances, antenna heights and elevations are integrated into its formula and long-term extreme seasonal variations are considered. Our study uses a wide set of measurements from the fixed wireless networks of a wireless internet service provider in rural regions of Canada. The proposed modifications improve the accuracy by 7 to 15 dB in terms of the root mean squared error.
In this paper we present an application for COVID-19 contact tracing based on device-to-device te... more In this paper we present an application for COVID-19 contact tracing based on device-to-device technology. This paradigm allows communication between two devices without the need for network infrastructure. Recently, various technologies such as Bluetooth and Wi-Fi Direct have been used in this field. Our approach is based on Wi-Fi Direct. We first explore similar approaches that have been developed. We then present the architecture of the proposed application and show a prototype implementation.
Instance Matching (IM) is the process of matching instances that refer to the same real-world obj... more Instance Matching (IM) is the process of matching instances that refer to the same real-world object (e.g., the same person) across different independent Knowledge Bases (KBs). This process is considered as a key step, for instance, in the integration of KBs. In this paper, we propose BIGMAT, a novel approach for the IM problem based on Markov random walks. Our approach bears in mind the local and global information mutually calculated from a pairwise similarity graph. Precisely, we first build an expanded association graph consisting of pairs of IM candidates. Then, we rank each candidate pair through the stationary distribution computed from the Markov random walk on the association graph. We provide a scalable distributed implementation on top of the Spark framework and we evaluate it on benchmark datasets from the instance track of the Ontology Alignment Evaluation Initiative (OAEI). The experiments show the efficiency and scalability of our approach compared to several state-of-the-art IM approaches.
Two of the main challenges in wireless sensor networks (WSNs) are connectivity and coverage. Conn... more Two of the main challenges in wireless sensor networks (WSNs) are connectivity and coverage. Connectivity keeps different nodes in the network linked and to exchange data. Coverage affects the efficiency of the operating sensors used in the network. This paper proposes a novel resilient incremental algorithm that improves the coverage of randomly distributed mobile devices within a heterogeneous or homogeneous environment. This algorithm guarantees connectivity by ensuring at least 2-connected neighbors for any device in the network. Results showed up to 89% coverage improvement in a heterogeneous environment and up to 99% coverage improvement in a homogeneous environment.
One of the main challenges in Wireless sensor network (WSN) is the connectivity and coverage. Con... more One of the main challenges in Wireless sensor network (WSN) is the connectivity and coverage. Connectivity is responsible of keeping the different nodes in the network connected and exchange data. Coverage impacts how efficient we are utilizing the operating sensors or mobile devices in the network. To provide a better performance to the connectivity in the network, one of the solutions is to maximize the coverage. This paper provides a novel resilient incremental algorithm which improves the coverage of connected mobile devices within a heterogeneous and homogeneous networks. Extensive simulations showed an improvement on the coverage up to 99% in homogeneous environments and 89% in heterogeneous environments.
The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.
International Journal of Distributed Sensor Networks, Feb 1, 2019
The failure of communications systems may cause catastrophic damage to human life and economic ac... more The failure of communications systems may cause catastrophic damage to human life and economic activities as people are unable to communicate with each other in a timely manner and with a convenient quality of service. Therefore, the exchange of information is more than necessary for people in their everyday life or during harsh environments to prevent the death and injury of thousands of individuals. The study of communications systems behavior in harsh environments helps to design or select more resilient technologies that are capable of operating in challenging conditions. This article reviews existing approaches, major causes of failure, and weaknesses of communications systems during extreme events. First, we highlight the importance of communications systems, and then we examine related works, how communication may fail, and the effect of this failure on human life in general and during extreme events response. Furthermore, we study and analyze how communications are used during various stages of extreme events, and we identify the main weaknesses and limitations that communications systems may suffer based on many case studies. To conclude, we identify and discuss relevant attributes, requirements, and recommendations for communications systems to perform with a suitable quality of service during harsh environments and to reduce risks of communication failure in challenging conditions.
HealthCare system is considered a key element in ubiquitous computing, which means health care se... more HealthCare system is considered a key element in ubiquitous computing, which means health care services are recommended at any time and at any places to monitor patients based on their context. This study aims to define a simple framework that could be guidelines when you start thinking about building a health context-awareness system in ubiquitous environment. This paper starts by defining the concept of context and then presenting a comprehensive list of context models. Outcome of the work of this research is an ontology healthcare model based on current context of patient which makes monitoring process more accurate. This study includes an Android application in order to prove the concept of this hypothesis.
This paper describes ubiquitous computing and context-aware applications. It presents briefly a s... more This paper describes ubiquitous computing and context-aware applications. It presents briefly a survey and contributions of our works and many others works done during the last years.
The separation of concerns as a conceptual paradigm, aims to manage the complexity of the softwar... more The separation of concerns as a conceptual paradigm, aims to manage the complexity of the software systems by dividing them into different concerns and aspects. The benefits of this paradigm such as adaptability, reuse and maintenance, have been key drivers of its adoption and usability. These quality attributes have been discussed in aspect-oriented programming (AOP) which is a complement to traditional programming methods, whether object-oriented programming or procedural programming. The main concept of AOP is to gather the treatments related to a specific concern (problem) in a centralized unit called aspect. In this paper, two case studies of AOP are conducted with AspectJ: i) through three different implementations, addressing three distinct issues: Logging, Adding features and Using the Observer design pattern, and ii) through the design of aspect mobile application that is easy to use and quickly accessible and especially through Android devices. Also, the different technologies of AspectJ are used to design our application and illustrate the modularity and the composition of components (database manager, development software, and plugins). For each case study, we present the advantages and disadvantages to better understand and decompose the applications using this programming paradigm. Potential implementation examples are provided to support the explanation of the different situations and justify the use of the AOP to solve these issues. OSGi framework can also be used in the future work to offer dynamic manner of mobile applications.
Recommendation technique is a personalized search used to assist a user access information/servic... more Recommendation technique is a personalized search used to assist a user access information/services that are related to his preferences and interests, or to the preferences and interests of similar users. The main challenge of personalized Information Retrieval is the modeling and the integration of user profiles. In this paper, we propose a generic model of user profiles based on the search history of users delimited by several search sessions. These profiles are based on weighted topical graphs and are integrated into a hybrid data recommendation process. To evaluate the proposed system a prototype is developed. The results are quite encouraging; they showed that our model is able to help users when searching for items.
The study of radio signal propagation path loss (PL) is important for planning, designing and eva... more The study of radio signal propagation path loss (PL) is important for planning, designing and evaluating the performance of radio communication networks. However, the state-of-the-art in PL modelling for fixed wireless networks in rural environments is still ill-equipped for making accurate predictions. This paper explores the application of the log distance PL model to heterogeneous fixed wireless networks in harsh rural propagation conditions. This model is then extended and optimized to improve its accuracy. In particular, the dataset is classified according to many criteria, radio links are split into many intervals according to their distances, antenna heights and elevations are integrated into its formula and long-term extreme seasonal variations are considered. Our study uses a wide set of measurements from the fixed wireless networks of a wireless internet service provider in rural regions of Canada. The proposed modifications improve the accuracy by 7 to 15 dB in terms of the root mean squared error.
In this paper we present an application for COVID-19 contact tracing based on device-to-device te... more In this paper we present an application for COVID-19 contact tracing based on device-to-device technology. This paradigm allows communication between two devices without the need for network infrastructure. Recently, various technologies such as Bluetooth and Wi-Fi Direct have been used in this field. Our approach is based on Wi-Fi Direct. We first explore similar approaches that have been developed. We then present the architecture of the proposed application and show a prototype implementation.
Instance Matching (IM) is the process of matching instances that refer to the same real-world obj... more Instance Matching (IM) is the process of matching instances that refer to the same real-world object (e.g., the same person) across different independent Knowledge Bases (KBs). This process is considered as a key step, for instance, in the integration of KBs. In this paper, we propose BIGMAT, a novel approach for the IM problem based on Markov random walks. Our approach bears in mind the local and global information mutually calculated from a pairwise similarity graph. Precisely, we first build an expanded association graph consisting of pairs of IM candidates. Then, we rank each candidate pair through the stationary distribution computed from the Markov random walk on the association graph. We provide a scalable distributed implementation on top of the Spark framework and we evaluate it on benchmark datasets from the instance track of the Ontology Alignment Evaluation Initiative (OAEI). The experiments show the efficiency and scalability of our approach compared to several state-of-the-art IM approaches.
Two of the main challenges in wireless sensor networks (WSNs) are connectivity and coverage. Conn... more Two of the main challenges in wireless sensor networks (WSNs) are connectivity and coverage. Connectivity keeps different nodes in the network linked and to exchange data. Coverage affects the efficiency of the operating sensors used in the network. This paper proposes a novel resilient incremental algorithm that improves the coverage of randomly distributed mobile devices within a heterogeneous or homogeneous environment. This algorithm guarantees connectivity by ensuring at least 2-connected neighbors for any device in the network. Results showed up to 89% coverage improvement in a heterogeneous environment and up to 99% coverage improvement in a homogeneous environment.
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Papers by Hamid Mcheick