Owing to the destructive impacts of harmonic currents, the topic of reducing their impacts on power system has attracted tremendous research interests. In this regard, a shunt active power filter (SAPF) is recognized to be the most reliable instrument. It performs by first detecting the harmonic currents that are present in a harmonic-contaminated power system, and subsequently generates and injects corrective mitigation current back into the power system to cancel out all the detected harmonic currents. This means that other than the ability to generate corrective mitigation current itself, it is actually more important to make sure that the SAPF is able to operate in phase with the operating power system, so that the mitigation current can correctly be injected. Hence, proper synchronization technique needs to be integrated when designing the control algorithms of SAPF. This paper critically discusses and analyzes various types of existing phase synchronization techniques which have been applied to manage operation of SAPF; in terms of features, working principle, implementation and performance. The analysis provided can potentially serve as a guideline and provision of information on selecting the most suitable technique for synchronizing SAPF with the connected power system.

Energy conservation and optimization remains the top researched field for wireless sensor networks, which is one of a subsets and the underlying communication medium for Internet of Things (IoT) devices. These constrained IoT devices are mostly battery operated and therefore requires robust and optimized algorithms to improve resources utilization which inherently increases the life-span for these devices without compromising Quality of Service (QoS). The communication radios on these nodes are the most power hogging components. Therefore, a major focus has always been on MAC and cross-layer protocols to optimize the duty cycle of radios for the conservation of energy. This paper presents a unique scheme for dynamically adjusting the duty cycle of nodes based on the arrival of incoming infrequent source node sensor data over which eliminates the need for frequent periodic channel assessment for network activity. The proposed scheme also makes use of ultra-low wakeUp receivers on the receiver nodes to further aid the node in energy conservation. In this paper, we describe the details of our design scheme, implementation and evaluation details in Contiki OS and Cooja simulator. The results are micro-benchmarked with ContikiMAC and X-MAC protocols, and an improvement in radio duty cycle is reported for lighter network traffic.

A leakage-free and disposable biochip for deoxyribonucleic acid (DNA) separation and detection is developed in this study. The biochip comprises of 50 mm long polydimethylsiloxane (PDMS) microchannel and copper electrodes engraved on flame retardant (FR-4) printed circuit board (PCB) substrate. An inhibitor made from photocurable diacrylate bisphenol-A polymer (DABA) was used to establish a permanent bonding between PDMS and PCB substrates. Pull-off test experiments resulted in average strength of 287.4 kPa and a standard deviation of ± 23.8 kPa. These results are comparable to recent studies on leak-free microfluidic applications. Meanwhile, the leakage test showed that the biochip could withstand a pressure of more than 190 kPa, which is sufficiently high for most DNA measurements. Finally, experiments performed on two different DNA samples indicated that the proposed design could accurately detect DNA fragments with current sensitivity higher than 100 nA, under electric field strength of 20 V/cm. The new design effectively seals the biochip, thus preventing leakage of liquid from the sensor matrix. Together with its biologically and electrochemically inert characteristic, it opens up possibilities in building a truly portable biosensing device.