This paper presents MHARS (Mobile Human Activity Recognition System), a mobile system designed to monitor patients in the context of Ambient Assisted Living (AAL), which allows the recognition of the activities performed by the user as well as the detection of the activities intensity in real time. MHARS was designed to be able to gather data from different sensors, to recognize the activities and measure their intensity in different user mobility scenarios. The system allows the inference of situations regarding the health status of the patient and provides support for executing actions, reacting to events that deserve attention from the patient’s caregivers and family members. Experiments demonstrate that MHARS presents good accuracy and has an affordable consumption of mobile resources.Keywords: Ambient Assisted Living, Human Activity Recognition, situation inference, mobile computing.
A research topic of growing interest is the convergence between Collaborative Systems and Ubiquitous Computing, where context awareness is becoming a tool for enhancing collaboration processes. The application of Ubiquitous Computing concepts in the improvement of collaboration strategies created a research front called Ubiquitous Collaboration. This article proposes a framework to aid the development of collaborative applications for ubiquitous environments, called MaPS. MaPS works at one relevant stage of the collaboration. It uses context information and user profiles to improve the search for peers and the selection of communication channels. The article proposes the framework, its requirements and its architecture. Moreover, we describe a prototype and two applications which were developed with it. The framework was evaluated considering software development, based on the experience got in the implementation of the applications and aspects of functionalities. It was made through a scenario involving active participants. The results of both evaluations show the potential for using MaPS.Keywords: collaboration, collaborative applications, ubiquitous computing, ubiquitous collaboration, ubiquitous environments, context awareness.
Advances in ubiquitous computing are enabling the emergence of opportunities in many areas; among them we highlight the health-related applications. In this area, there is a trend toward developing many applications that enable care wherever you are and whenever you need, called ubiquitous healthcare. A detailed survey of existing and proposed models has shown that none of these applications meets the needs of people who suffer from food allergy. Thus, this article proposes an allergy detection ubiquitous model based on situation awareness. This model, called Allergy Detector, focuses on food allergy, in particular the eight major allergens (peanut, milk, egg, wheat, soy, fish, crustacean and tree nuts) and their derivatives, which cause about 90% of all food allergies. The main scientific contribution of the Allergy Detector is the use of situation awareness for detecting allergies anytime and anywhere in a transparent manner. In order to assess the model, we designed some case studies. We also carried out a profiling, accessing the Allergy Detector in terms of performance and identifying the main bottlenecks. The results showed the feasibility of using the model for detecting allergy ubiquitously.Keywords: ubiquitous computing, context awareness, ubiquituos health.
Even though human activities may result in injuries, there is not much discussion in the academy of how ubiquitous computing could assess such risks. So, this paper proposes a model for the Activity Manager layer of the Activity Project, which aims to predict and infer risks in activities. The model uses the Activity Theory for the composition and prediction of activities. It also infers the risk in actions based on changes in the user’s physiological context caused by the actions, and such changes are modeled according to the Hyperspace Analogue to Context model. Tests were conducted and the developed models outperformed proposals found for action prediction, with an accuracy of 78.69%, as well as for risk situation detection, with an accuracy of 98.94%, showing the efficiency of the proposed solution.Keywords: activities of daily living, Activity Theory, activity recognition, activity prediction, risk in actions.
The complexity of applications in the mobile crowdsensing domain is due to factors such as interoperability among heterogeneous devices, recruiting of devices, collection of data from these devices, and adaptation of application operation in dynamic environments. This paper introduces a platform based on models at runtime (M@RT) for the development of the mobile crowdsensing functionality of applications. The platform supports model-based creation and processing of queries that target a distributed and dynamic set of sensor-capable devices. The paper also presents the results of an evaluation that shows the impact of runtime model processing on the performance of applications in mobile crowdsensing scenarios. Keywords: participatory sensing, models at runtime, model execution engine, mobile computing.
The skill level of a person in processing information, reacting to his/her surroundings and decision making for performing an activity is determined by the allocation of the mental resources demanded by such activity. When the allocation is inappropriate, there is a higher possibility for some accident to occur. Thus, one can notice that the cognitive workload spent by the person is an important variable that can take him to a risky situation. Since it is not possible to measure the cognitive workload spent by a person during the performance of an activity directly, we noticed the need to evaluate the level of his/her performance in order to be possible to infer the cognitive workload used. So, we propose the creation of a model to classify the cognitive workload based on the behavioral model skill-rule-knowledge and the relations of performance properties with the context surrounding the person. The evaluation of the model was made using a public dataset and the results showed a promising approach for the classification of human performances. Keywords: human activity, context-aware middleware, ubiquity, cognitive workload, human performance.
In Wireless Sensor Networks (WSNs), sensor nodes detect environment events and send them to sink nodes, which are responsible for processing these events. Due to the reduced of the nodes, the biggest restriction in a WSN is related to power consumption. Sender-based and receiver-based communication protocols each have their own advantages and disadvantages in certain scenarios. Since a WSN can undergo alterations in time, a protocol that is able to adapt to environmental conditions can increase network lifetime. This paper presents a hybrid routing protocol that operates according to sender-based and receiver-based approaches. The protocol was implemented using the NS-2 simulator and compared to sender-based and receiver-based approaches operating on their own. The results showed that the hybrid protocol, compared to sender and receiver-based approaches, achieves delivery rates close to 100%, performing 2.9 times less transmissions for each packet delivered. These gains demonstrate the contribution of the proposed algorithm, which reduces the number of transmissions, allowing the WSN to have a longer survival time. Keywords: hybrid sender and receiver protocol, Wireless Sensor Networks, routing protocol, simulations.
Sensor networks have been used in a wide range of applications. In Digital Cities they play an important role in gathering real-time data in urban scale. However, the heterogeneous and complex technologies applied in such applications make it difficult to monitor and manage different sensor networks, and also prevents the interoperation between systems. Thus, this paper presents a proposal of a novel architecture based on service orientation for homogeneous interoperation among sensor networks used in a Digital City scenario. Based on the outlined architectural model, a case study took place in a Brazilian operational Digital City in the state of Sao Paulo. The objective of the study is to demonstrate that architecture can be used for monitoring heterogeneous environments in a unified way, promoting datasharing and interoperability. Keywords: Service-oriented architectures, Open Access Metropolitan Area Networks, ZigBee, sensor networks.
Nowadays, Brazil has an expected growth in the tourism sector due to the FIFA World Cup (which had a huge success) and the Olympics in Rio de Janeiro. However, there is a lack of tourism applications for Brazil, such as Electronic Tourism Guides (ETGs) for mobile devices. The existence of ETGs that takes into account real world environment is still very rare. By taking into account this scenario, this article presents a ubiquitous tourism model based on augmented reality. The proposed architecture, which is called UbitourAR, takes into account the context awareness focusing on localization-based services allied with user profile and restrictions. This article describes the development of UbitourAR enabling users to interact with the real world environment using augmented reality when visiting a place or point of interest (POI). In order to evaluate the model we had taken two approaches. Firstly, we evaluated the ontology proposed using scenarios. Secondly, we evaluated the usability in terms of efficiency, effectiveness and user satisfaction. For doing that, we developed a mobile application for the Caminhos de Pedra itinerary, in Bento Goncalves, Brazil. The proposed model extends the previous work of Ubitour by adding augmented reality. The results of the tests showed a user acceptance higher than 80%, which encourages the research in augmented reality allied with ubiquitous tourism. Keywords: augmented reality, Web Semantics, ubiquitous tourism, ubiquitous computing, mobile computing.
The medication therapy process i n the hospital environment is complex and error prone. We consider that the use of technology can automate the verification of this process, reducing the number of errors during the treatment. Thus, this work proposes a software architecture aimed to provide the patient’s current situation awareness, called EXEHDA-TG. As a central contribution, this work provides the monitoring of the patient’s vital signs, allowing the physician to confirm that the desired effect with the administration of medications is being reached. In the developed architecture, this effect desired by physicians in vital parameters is called Therapeutic Goal (TG). The evaluation of EXEHDA-TG was taken through three usage scenarios. The results have been satisfactory in the analysis of the evolution of vital signs. Keywords: ubiquitous computing, situation awareness, therapeutic goal.
Semantic clustering is a recent technique for saving energy in wireless sensor networks. Its mechanism of action consists in dividing the network into groups (clusters) formed by semantically related nodes and at least one semantic collector, which acts as a bridge between its internal nodes and the sink node. Since semantic collector nodes need to perform more tasks than normal nodes, they deplete their energy budget faster, so it is necessary to use efficient mechanisms for electing semantic collectors to prolong the network lifetime. Our hypothesis is that an effective choice of semantic collectors allows a longer network lifetime. To test it, we start from a previous work of the authors of this article and we propose an algorithm for electing semantic collectors in a distributed way based on a fuzzy inference engine. The inputs of the inference engine are the residual energy of nodes and their received signal strength indicator (RSSI). Simulation results confirm our hypothesis, since the algorithm provides (i) an improvement of 17.4% in relation to another proposal of the related literature, and (ii) a gain of 68.8% over the time life of the network’s original work. Keywords : Wireless Sensors Networks, Semantic Cluster, Semantic Collector Election.
This work presents a probabilistic constructive heuristic to support the design of roadside infrastructure for information dissemination in vehicular networks. We formulate this as a Probabilistic Maximum Coverage Problem (PMCP) and we intend to maximize the number of vehicles that get in contact with the infrastructure. We compare our approach with non-probabilistic MCP in simulated urban areas following a Manhattan-style topology with variable traffic conditions. The main contributions of this work are (i) the formal definition of the Probabilistic Maximum Coverage Problem, (ii) the application of PMCP to solve one instance of the problem of facilities allocation and (iii) the application of a probabilistic approach to model the volume of vehicles along the urban area, where the position of each vehicle is no longer considered deterministic, but it is treated as a probability function distributed over all the intersections. The vehicles no longer have a position. Instead, vehicles have a probability of being in a given position at a given instant of time. The results reveal that PMCP requires less dissemination points (DPs) to achieve similar coverage ratio than non-probabilistic MCP, while preserving the same samples deviation. Keywords: vehicular networks, maximum coverage problem, information dissemination.
Vehicular networks represent a special type of wireless network that has gained the attention of researchers over the past few years. Routing protocols for this type of network must face several challenges, such as high mobility, high speeds and frequent network disconnections. This paper proposes a vehicular routing algorithm called RouteSpray that in addition to using vehicular routes to help make routing decisions, uses controlled spraying to forward multiple copies of messages, thus ensuring better delivery rates without overloading the network. The results of experiments performed in this study indicate that the RouteSpray algorithm delivered 13.46% more messages than other algorithms reported in the literature. In addition, the RouteSpray algorithm kept the buffer occupation 73.38% lower. Keywords: wireless networks, vehicular networks, routing protocols.
Opportunistic Networks (ONs) are mobile networks that support intermittent links and long delays. ON nodes exchange data in brief moments called contacts, when another node is within radio range. Contacts are ephemeral and unpredictable, thus they must be implemented as efficiently as possible. However, most previous work rely on simplistic assumptions such as unlimited bandwidth and contentionfree transmissions. This paper presents a more realistic evaluation of ON contacts. Simulations show that, on opposition to the consensus in the literature, routing protocols that forward more copies and those that determine a subset of nodes to receive the Bundles using a certain criteria outperform flooding-based protocols, because the latter generates too much medium contention. Finally, buffer management and forwarding prioritization may influence the performance of the network by up to 30%. Keywords: Opportunistic networks, simulation, Delay-Tolerant Networks.
Ubiquitous computing aims to make tasks that depend on computing transparent to the users, providing resources and services anytime and anywhere. This paper proposes a computational model to support ubiquitous libraries. The model provides appropriate information and tools to the librarian to maintain resources and services in a library, as well tools that allow offering better services to the library users. We developed a prototype that has been evaluated by thirteen volunteers in the Library of Centro Universitario Univates (Univates). The results showed a good acceptance of the model. Keywords: Ubiquitous Computing, Mobile Computing, Ubiquitous Libraries, Intelligent Systems.
The applications in Ubiquitous Computing (UbiComp) environments must be aware of their contexts of interest and adapt to changes in them. Thus, a major research challenge in the area of UbiComp is related to context awareness. Considering the high distribution, heterogeneity, dynamism, and mobility of ubiquitous environments, this paper presents an architectural model for context awareness, called EXEHDAUC (Execution Environment for Highly Distributed Applications - Ubiquitous Context awareness). The proposal includes elements to support contextual data acquisition, actuation in the environment, and processing of contextual information. We consider that the main contribution of this work is an architecture that supports the managing of the acquisition, storage, and processing of context data, in a distributed way, independently of the application, in an autonomic and rule-based perspective. To assess the functionalities of the EXEHDA-UC, we present a case study, highlighting the prototypes developed, technologies employed, and tests carried out. Keywords: ubiquitous computing, context awareness, distributed architecture.
In conferences, congresses and symposia, there are issues that may be handled by applications running in mobile devices. In these environments, Audience Response Systems can be used to increase iteration between participants. This paper aims to evaluate the usability of two Audience Response Systems, namely Simple Question and Voting, developed for collaborative proposals. We employed a set of 15 heuristics for mobile groupware evaluation, which includes three fundamental aspects of mobile groupware applications: HCI, mobilit y, and collabo ration. In the evaluation performed in this work, three specialists used the heuristics to evaluate both systems interfaces. The evaluation was conducted in three steps: (i) exploration of the system and its features; (ii) usability evaluation; (iii) consolidation of the collected data and reflection. The evaluation results of Simple Question and Voting indicated than both are in accordance with some usability aspects. However, we also identified common problems, such as non-appropriate communication methods, low coordination, and group management. Based on the results and experiences obtained over this evaluation, we argue that the heuristic set presented is applicable to evaluate mobile groupware usability.Keywords: heuristic evaluation, mobile groupware, usability.
This article aims to present the first ideas for developing a framework for load-balancing called GetLB. Considering the electronic funds transfer (EFT) context, GetLB offers a new scheduling heuristic that optimizes the selection of Processing Machines to execute transactions in a processing center. Instead of using the Round-Robin typical approach, the proposal combines data from computation, network, memory and disc metrics for producing a unified scheduling approach, denoted LL (i,j). The proposal calculates the load level of executing an i-typed transaction on a j specific Processing Machine. Furthermore, the load-balancing framework also enables notifications triggered by Processing Machines to the Dispatcher for informing it about asynchronous events such as administrative tasks or transactions disposing. Aiming to evaluate GetLB, a simple prototype was developed by using Java RMI. Preliminary tests revealed that the framework is feasible, outperforming the number of queued transactions obtained with the Round-Robin approach.Keywords: Electronic Funds Transfer, transactions, load balancing, remote method invocation
Recently, virtualization is becoming increasingly popular due to its wide adoption in cloud computing. This success stems from the fact that the infrastructure scales better and configuration and recovery tasks become simpler. Despite the benefits, the performance impact due to virtualization represents a major challenge for the establishment of accurate Service Level Agreements (SLA). This work presents an approach for monitoring and analysis of performance in virtualized environments. Experiments with generation of synthetic workloads in our monitored infrastructure allowed us to identify the main causes of the observed degradation of performance. Further, some specific behaviors were noticed for different load profiles.Key words: performance analysis, performance monitoring, virtualization.
Increasingly popular, Internet applications for multimedia broadcasting require multipoint communication, in order to reduce network traffic rates. However, the widespread adoption of traditional multicast protocols is still held back by the current Internet structure, where the responsibility for management of multicast groups is distributed among network devices. By using distributed algorithms, such protocols generate delays in processing control groups events. In this paper we propose a clean-slate approach for multimedia multicasting, where the end to end calculation of the best route is performed to decrease delays in group configuration. The prototype developed implements this approach using OpenFlow technology. Results obtained through experimentation show a performance gain in relation to traditional IP multicasting.Key words: Multicast, SDN, OpenFlow.
