Use of mobile health (mHealth) systems has increased with the advancement and proliferation of mobile computing and related technologies. It has improved efficiency and effectiveness of healthcare services. Non-invasive pain level detection from facial images is one of the promising mHealth applications. Effective pain treatment requires regular and continuous pain assessment. Most of the pain research tools are study or disease specific while some are pain (lumbar pain, cancer pain, etc.) and patient group specific (neonatal, adult, woman, etc.). This results in recurrent but potentially avoidable costs such as time, money, and workforce to develop similar services or software research tools for each research study. In this study, we have proposed, designed, and implemented a customizable personalized pain study platform that offers real-time data collection, research participant management, role-based access control, research data anonymization etc. It is also used to investigate pain level detection accuracy using evidence-based continuous learning from the facial expression data, collected from Bangladesh, Nepal and USA, which yielded about 71% classification accuracy.

Duty-cycle MAC protocols have been proposed to meet the demanding energy requirements of wireless sensor networks. Although existing duty-cycle MAC protocols such as S-MAC are power efficient, they introduce significant end-to-end delivery latency and provide poor traffic contention handling. In this paper, we present a new duty-cycle MAC protocol, called RMAC (the routing enhanced MAC protocol), that exploits cross-layer routing information in order to avoid these problems without sacrificing energy efficiency. In RMAC, a setup control frame can travel across multiple hops and schedule the upcoming data packet delivery along that route. Each intermediate relaying node for the data packet along these hops sleeps and intelligently wakes up at a scheduled time, so that its upstream node can send the data packet to it and it can immediately forward the data packet to its downstream node. When wireless medium contention occurs, RMAC moves contention traffic away from the busy area by delivering data packets over multiple hops in a single cycle, helping to reduce the contention in the area quickly. Our simulation results in ns-2 show that RMAC achieves significant improvement in end-to-end delivery latency over S-MAC and can handle traffic contention much more efficiently than S-MAC, without sacrificing energy efficiency or network throughput.

Simulation and physical implementation are both valuable tools in evaluating ad hoc network routing protocols, but neither alone is sufficient. In this paper, we present the design and performance of PRAN, a new system for the physical implementation of ad hoc network routing protocols that unifies these two types of evaluation methodologies. PRAN (physical realization of ad hoc networks) allows existing simulation models of ad hoc network routing protocols to be used - without modification - to create a physical implementation of the same protocol. We have evaluated the simplicity and portability of our approach across multiple protocols and multiple operating systems through example implementations in PRAN of the DSR and AODV routing protocols in FreeBSD and Linux using the standard existing, unmodified ns-2 simulation model of each. We illustrate the ability of the resulting protocol implementations to handle real, demanding applications by describing a demonstration with this DSR implementation transmitting real-time video streams over a multihop mobile ad hoc network; the demonstration features mobile robots being remotely operated based on the real-time video stream transmitted from the robot over the network. We also present a detailed performance evaluation of PRAN to show the feasibility of our architecture

In this paper, we present the initial design and evaluation of two techniques for routing improvement using directional antennas in mobile ad hoc networks. First, we use directional antennas to bridge permanent network partitions by adaptively transmitting selected packets over a longer distance, still transmitting most packets a shorter distance. Second, in a network without permanent partitions, we use directional antennas to repair routes in use, when an intermediate node moves out of wireless transmission range along the route; by using the capability of a directional antenna to transmit packets over a longer distance, we bridge the route breakage caused by the intermediate node's movement, thus reducing packet delivery latency. Through simulations, we demonstrate the effectiveness of our design in the context of the dynamic source routing protocol (DSR).

Summary form only given. Recent advances in technology have made low-cost, low-power wireless sensors a reality. A network of such nodes can coordinate among themselves for distributed sensing and processing of certain phenomena. We propose an architecture to provide a stateless solution in sensor networks for efficient addressing and routing. We name our architecture TreeCast. We propose a unique method of address allocation, building up multiple disjoint trees which are geographically inter-twined and rooted at the data sink. Using these trees, routing messages to and from the sink node without maintaining any routing state in the sensor nodes is possible. Next, we use this address allocation method for scoped addressing, through which sensor nodes of a particular type or in a particular region can be targeted. Evaluation of our protocol using ns-2 simulations shows how well our addressing and routing schemes perform.

Recent advances in technology have made low cost, low power wireless sensors a reality. Clock synchronization is an important service in any distributed system, including sensor network systems. Applications of clock synchronization in sensor networks include data integration in sensors, sensor reading fusion, TDMA medium access scheduling, and power mode energy saving. However, for a number of reasons, standard clock synchronization protocols are unsuitable for direct application in sensor networks. In this paper, we introduce the concept of adaptive clock synchronization based on the need of the application and the resource constraint in the sensor networks. We describe a probabilistic method for clock synchronization that uses the higher precision of receiver-to-receiver synchronization, as described in Reference Broadcast Synchronization (RBS) protocol. This deterministic protocol is extended to provide a probabilistic bound on the accuracy of the clock synchronization, allowing for a tradeo between accuracy and resource requirement. Expressions to convert service specifications (maximum clock synchronization error and confidence probability) to actual protocol parameters (minimum number of messages and synchronization overhead) are derived. Further, we extend this protocol for maintaining clock synchronization in a multihop network.