International Journal of Sensor Networks and Data Communications

This editorial briefly examines challenges in design of adaptive decision feedback equalizers for multi-Gbps serial links. The state-of-the-art of serial links over wire channels is briefly reviewed. The impairment of wire channels at high frequencies and their effect on the performance of serial links are examined. It is followed with a close examination of channel equalization techniques to combat inter-symbol interference. Challenges and opportunities in design of adaptive feedback equalizers including timing constraints, power consumption, adaptive references for error generation and thresholds for logic state determination, data-DFE, eye-opening monitor DFE, and edge-DFE, floating tap DFE are examined.

A scalable microwire peripheral nerve interface was developed, which interacted with regenerated peripheral nerves in microchannel scaffolds. Neural interface technologies are envisioned to facilitate direct connections between the nervous system and external technologies such as limb prosthetics or data acquisition systems for further processing. Presented here is an animal study using a handcrafted microwire regenerative peripheral nerve interface, a novel neural interface device for communicating with peripheral nerves. The neural interface studies using animal models are crucial in the evaluation of efficacy and safety of implantable medical devices before their use in clinical studies. 16-electrode microwire microchannel scaffolds were developed for both peripheral nerve regeneration and peripheral nerve interfacing. The microchannels were used for nerve regeneration pathways as a scaffolding material and the embedded microwires were used as a recording electrode to capture neural signals from the regenerated peripheral nerves. Wireless stimulation and recording capabilities were also incorporated to the developed peripheral nerve interface which gave the freedom of the complex experimental setting of wired data acquisition systems and minimized the potential infection of the animals from the wire connections. A commercially available wireless recording system was efficiently adopted to the peripheral nerve interface. The 32-channel wireless recording system covered 16-electrode microwires in the peripheral nerve interface, two cuff electrodes, and two electromyography electrodes. The 2-channel wireless stimulation system was connected to a cuff electrode on the sciatic nerve branch and was used to make evoked signals which went through the regenerated peripheral nerves and were captured by the wireless recording system at a different location. The successful wireless communication was demonstrated in the result section and the future goals of a wireless neural interface for chronic implants and clinical trials were discussed together.

Despite being the most efficient automatic repeat request (ARQ) protocol, the selective-repeat ARQ (SR-ARQ) is previously thought to be infeasible in underwater acoustic communications owing to the half-duplex property of typical underwater acoustic modems. However, with the help of the juggling-like stop-and-wait (JSW) transmission scheme, it has now become feasible. In this paper, we evaluate the delivery delay (consisting of transmission and resequencing delays) of the SR-ARQ operating over the JSW scheme under the static assumption that the relative radial velocity between the transmitter and the receiver is zero, aiming to provide system designers with a valuable reference for delay evaluation under more general scenarios. We model the underwater acoustic channel as a two-state Discrete Time Markov Channel, and derive the closed-form expression for the delivery delay under heavy traffic situation. Unlike most analytical approaches for the delay analysis of SR-ARQ in terrestrial communications whose computational complexities grow exponentially with round-trip delay, our proposed analytical approach is immune to the round-trip delay. This also makes our approach suitable for terrestrial communications. To highlight the accuracy of our approach, we also provide comparisons between analytical and simulation results.

In this paper, experiments are conducted to evaluate the efficacy of a novel adaptive power control algorithm in terms of energy efficiency in heart rate monitoring scenario of a mobile adult in a typical home environment. As part of health care, persons with heart related problems are required to be monitored by logging for example, their heart rate on a regular basis to check for any anomaly. At the same time, it is expected that the person in question should be able to move freely within the given facility. The wireless sensors that are attached to the person send periodic data to the central base station. Since the person is mobile, the distance between the transmitting sensor and the base station changes with time. Since the signal path-loss is primarily dependent on distance and the number and type of obstructions between the transmitter and the receiver, it may be wise to use transmission power control to modulate the transmit power. Using power control, the sensor can adjust the level that is sufficient to send the data through the wireless channel without wasting energy. Conservation of energy is critical in wireless sensor network scenarios because they are powered by batteries which have limited lifetime. A critical application like the heart rate monitoring sensor is expected to operate for a reasonable amount of time before the battery dies. The novel adaptive power control algorithm uses intelligent modulation methods to ramp up or ramp down the transmission power level as and when required. By this method, the operational lifetime of the wireless sensor can be extended. As part of the experimental methodology for this paper, two subjects of different age groups have been used. Experimental results show that there is at least a 12% increase in the energy savings using the proposed algorithm.

Wireless Multimedia Sensor Networks (WMSNs), is a network of sensors which are limited in terms of computational, memory, bandwidth, and battery capability. Multimedia transmission over WSN requires certain Qos guarantees such as huge amount of bandwidth, strict delay and lower loss ratio, which makes transmitting multimedia content over it, is a challenging problem. Recently adopting cross-layer design in WMSNs proved to be a promising approach, which improves quality of service of WSN under various operational conditions. In this work, an energy aware framework for transmitting multimedia content over WSN (ECWMSN) is presented, where packet and path scheduling were introduced, so that It adaptably selects optimum video encoding parameters at application layer according to current wireless channel state, and schedules packets according to its type to drop less important packets in case of network congestion. Finally, path scheduling is introduced so that different packets types/priority is routed through suitable path with suitable Qos taking into consideration the network lifetime. Simulation results show that ECWMSN optimizes video quality and prolongs network lifetime.

Wireless sensor networks are comprised of low power devices with fixed energy stores. They often require long term operation for successful deployment so it is important to efficiently manage and track their energy usage. To effectively accomplish this across distributed networks requires methods which have low energy cost with minimal error. In this paper we present a straightforward model for energy consumption in wireless sensor networks which is light-weight and accurate. The model has been applied to a wireless sensor network developed by the Queen's University MEMs lab and is evaluated with a custom testbed. Through testing, the model is exposed to realistic disturbances of communication loss, battery effects and variable voltage supplies. It was shown that with 99% packet reception rates in the network, the model accurately estimates end node energy consumption with less than 5% error. These results were demonstrated across varying data rates, battery supply capacities, and runtimes up to full network lifetime.

This article describes a method to translate an evidence based health care intervention to the mobile environment. This translation assisted patient participants to: avoid life threatening infections; monitor emotions and fatigue; keep involved in healthy activities. The mobile technology also decreased costs by reducing for example travel to visit health care providers. Testing of this translation method and its use by comparison groups of patients adds to the knowledge base for assessing technology for its impact on health outcome measures. The challenges and workflow of designing materials for the mobile format are described.

Transitioning clinical trial verified interventions, previously provided in person to patients, onto tablet and internet platforms is an important process that must be evaluated. In this study, our evidence based guide’s intravenous (IV) homeCare interventions (IVhomeCare) were delivered via Apple iPad miniTM tablet audiovisual instruction / discussion sessions and on a website. Each iPad audiovisual session (n = 41), included three to five families, a mental health specialist, and healthcare professionals. Patients and their family caregivers readily learned to use the wireless mobile tablets, and the IVhomeCare interventions, as described here, were successfully translated onto these mobile technology platforms. Using Likert scale responses on a questionnaire (1 = not helpful and 5 = very helpful) participants indicated that they gained problem solving skills for home care through iPad group discussion (M = 4.60, SD = 0.60). The firewall protected videoconferencing in real time with multiple healthcare professionals effectively allowed health history taking and visual inspection of the patient’s IV insertion site for signs of infection. Supportive interactions with peer families on videoconferencing were documented during discussions. Discussion topics included low moods, fatigue, infection worry, how to maintain independence, and need for support from others with their same lifelong IV experiences. The visual family interactions, discussions with professionals, and the iPad internet links were highly rated. Mobile distance care delivery can result in saved time and money for both healthcare professionals and families.