The harsh testing environments of underwater scenarios make it extremely hard to plan a reasonable routing protocol for Underwater Sensor Networks (UWSNs). The main challenge in UWSNs is energy confinement. It is needed to plan an energy effective scheme which increases the life span of the network and also reduces the energy usage in data transfer from supplier to sink. In this research, we present the design of a routing protocol known as Energy Harvesting in UWSN (EH-UWSN). EH-UWSN is a compact, energy efficient, and high throughput routing protocol, in which we present utilization of energy gaining with coordinating transfer of data packets through relay nodes. Through Energy Harvesting, the nodes are capable to recharge their batteries from the outside surrounding with the ultimate objective to improve the time span of network and proceed data through cooperation, along with restricting energy usage. At the sink node, the mixing plan applied is centered on Signal-to-Noise Ratio Combination (SNRC). Outcomes of EH-UWSN procedure reveal good results in terms of usage of energy, throughput, and network life span in comparing with our previous Cooperative Routing Scheme for UWSNs (Co-UWSN). Simulation results show that EH-UWSN has consumed considerably lesser energy when compared with Co-UWSN along with extending network lifetime and higher throughput at the destination.

This study proposes an advanced control scheme for the interlinking inverters of the hybrid AC/DC microgrids, which facilitates a seamless transition between grid-connected and stand-alone/islanding modes for the microgrid. Due to a nonlinear relationship between the terminal voltages of the voltage-source inverter (VSI) interfacing through inductor–capacitor (LC) filters with the grid voltages and currents, a feedback linearization technique (FLT) is employed to control the interlinking VSI under both grid-connected and islanding operations. The FLT-based current controllers are applied in the grid-connected mode, in which they adjust the power exchange between the DC and AC subgrids and mitigate the distortion of the grid currents produced by nonlinear loads. Under the stand-alone operation, the AC bus voltages are directly regulated by the FLT-voltage controllers of the interlinking VSI. In order to reduce the inrush currents and voltage overshot at the instant of mode switching, the FLT-based controllers are performed all the time regardless of the operating modes, where the voltage references for the VSI are not changed abruptly. The control performance of the VSI is highly satisfactory with low-transient overshoot values of the voltages and currents and low total harmonic distortion (THD) values of the grid currents and AC bus voltages are about 3.5% and 2.7%, respectively, under the nonlinear load condition. The validity of the new control strategy is verified by the simulation work, which investigates the operation of a hybrid AC/DC microgrid.

This study deals with fault ride-through (FRT) capability and output power fluctuation suppression of wind turbine systems (WTS) having PMSG (permanent-magnet synchronous generator) for mitigating grid frequency variation and voltage flicker in the distribution system. The coordinated control of a cost-effective scheme based on energy storage supercapacitors (ESSs) and braking resistors (BR) is introduced to perform the multiple tasks of the WTS. In this hybrid scheme, the ESSs are initially used to absorb the fluctuated power component with the constraints of their ratings during the grid faults and wind speed variation conditions prior to the activation of the BRs when the ESSs cannot fully consume the mismatched power between the PMSG and grid during severe grid faults. With the additional BRs, the capacity of the costly ESSs is remarkably reduced, while the performance of the fault ride-through capability and power smoothening for the WTS are still kept satisfactory and in compliance with the requirements of advanced grid codes. Detailed experimental implementation and its results for a down-scaled prototype in a laboratory are shown to verify the effectiveness of the introduced scheme along with the simulation results with the high-power rating WTS.

| The government of Khyber Pakhtunkhwa in the year 1999, started a new strategy of Farm Services Center for the empowerment of farmers that aimed to provide agricultural inputs like seeds, fertilizers, pesticides, machinery along with advisory services in order to increase per acre yield. This study was conducted in Khyber Pakhtunkhwa province in the year 2016. The study was conducted to assess the effectiveness of Farm Services Centers (FSCs) in district Charsadda regarding provision of agricultural services to its member farmers. About 57% respondents were registered with FSC since last 4-6 years period. Also 57% of the respondents mentioned that the extension agent was the source of awareness about FSC. About 43% of the respondents were invited by FSC for general body meeting whereas only 26% participated in the process of election. Maximum respondents were provided farm machinery by FSC i.e. cultivator (51%), rotavator (56%), mold bold plough (56%), disk plough (48%), single furrow (47%), drill (61%) and ridge maker (53%). Market was the source of seed for majority of the respondents regarding cauliflower (43%), bitter gourd (32%), bottle gourd (13%), potato (34%) and squash (29%). Similarly, majority of the respondents obtained urea (73%), SSP (54%), DAP (60%) and Nitro-Phos (55%) from the FSC whereas 91%, 99% and 96% respondents obtained Micron, Supper Silica and Gypsum from the concerned dealers. It is concluded that there was a gap in invitation of farmers for general body meeting and participation in elections by FSC members. FSC administration did not fulfill its obligation regarding provision of vegetable seed to its members resultantly they purchased seeds from the open market. Due to effective services of FSCs, farmers were inclined towards the cultivation of vegetables on larger areas and hence achieved significant yield of these selected vegetables in the study area. It is suggested that steps should be taken so that the participation of farmers in general body meetings and elections of FSC should be enhanced so that the trust of farmers be developed and they would be able to reach the solution of their problems. Timely availability of vegetable seeds along with subsidy should be ensured so that farmers can avail this opportunity.

KSII Transactions on Internet and Information Systems TIIS Paper Details