Journal Staff

Integration of renewable resources such as remote solar or wind farms and electricpower trading between neighbouring countries lead to new requirements on the development of thetransmission grids. Since AC grid expansion is limited by e.g. legislations issues, High VoltageDirect Current (HVDC) technology with its diverse benets compared to AC is being considered asappropriate alternative solution. The developed HVDC grid can be either embedded inside one ACgrid or connects several AC areas. In both architectures, the separate DC supervisory control can beproposed to control the HVDC grids using the interfacing information from AC Supervisory ControlAnd Data Acquisition (SCADA). The supervisory control is supposed to calculate the optimal power ow (OPF) in order to run the system in the most optimal situation. Based on the architecture, therequired information, boundary of the system and also objective function can vary. The aim of the thesis is to present the ndings of a feasibility study to implement a supervisorycontrol for bipolar Voltage Source Converter (VSC) HVDC grids in possible real time platforms. DCsupervisory control has a network topology manager to identify the grid conguration and employsan OPF calculator based on interior point optimization method to determine the set-point valuesfor all HVDC stations in a grid. OPF calculator takes into account the DC voltage, converter andDC line constraints.i

Assessment of Productivity Status Using Carlson’s TSI and Fish Diversity of Goronyo Dam, Sokoto State, Nigeria

Goronyo Dam is the largest lentic waterbody in Sokoto, it was constructed to serve as flood control and used for irrigation activities. The study was conducted to evaluate productivity status and fish diversity of Goronyo Dam in 2016. Water samples were collected monthly from the Dam at two sampling sites (Upstream and Downstream). Water samples were collected using sterilized sampling bottles and analyzed in the Laboratory for physicochemical variables and the diversity of fish was evaluated through the use of a structured questionnaire. Depth and transparency were the only variables that did not show any statistically significant difference between the months. Productivity status of the dam was evaluated using Carlson’s Trophic State Index. The downstream has high TSI value of 16.54 compared to upstream with 13.00. A diversity of fishes from the shows that 3 species were more abundant in the dam, these were; Mormyrops species, Alestes species and Clupeid species. Factors contributed to the survival of fish species were an abundance of water and plankton in the dam. While factors affecting the distribution of fish species were pollution and predation

Comparing SVM and Naive Bayes classifiers for text categorization with Wikitology as knowledge enrichment

The activity of labeling of documents according to their content is known as text categorization. Many experiments have been carried out to enhance text categorization by adding background knowledge to the document using knowledge repositories like Word Net, Open Project Directory (OPD), Wikipedia and Wikitology. In our previous work, we have carried out intensive experiments by extracting knowledge from Wikitology and evaluating the experiment on Support Vector Machine with 10- fold cross-validations. The results clearly indicate Wikitology is far better than other knowledge bases. In this paper we are comparing Support Vector Machine (SVM) and Na\"ive Bayes (NB) classifiers under text enrichment through Wikitology. We validated results with 10-fold cross validation and shown that NB gives an improvement of +28.78%, on the other hand SVM gives an improvement of +6.36% when compared with baseline results. Na\"ive Bayes classifier is better choice when external enriching is used through any external knowledge base.Comment: 5 page

The real exchange rate of an oil exporting economy: Empirical evidence from Nigeria

In this study the long-run relationship between real oil price, real effective exchange rate and productivity differentials is examined using annual data for Nigeria over the period 1980 to 2010. We aim to investigate whether oil price fluctuations and productivity differentials affect the real effective exchange rate. The empirical results suggest that whereas real oil price exercise a significant positive effect on the real exchange rate in the long run. Productivity differentials exercise a significant negative influence on the real exchange rate. The study noted that, the real exchange rate appreciation of 2000-2010 was driven by oil prices. The findings of this study have important implications for exchange rate policy and are relevant to many developing economies where oil exports constitute a significant share of their exports.Exchange rate, oil price, Nigerian economy

Evaluation of Physico-Chemical and Fungal Species Associated with Oil Contaminated Soil from Selected Automobile Garage in Sokoto Metropolis

This study was conducted with a view to evaluating the physicochemical and mycological properties of different oil contaminated soils collected from three different automobile garages in Sokoto Metropolis, and uncontaminated soil from the temporary site, Usmanu Danfodiyo University, Sokoto (UDUS) was used as the control. The pH was determined using pH meter model Hanna (H1991301), quantity of mineral elements was evaluated in accordance with Murphy and Fungi were isolated from the three oil contaminated samples (A, B. and C) and the uncontaminated (sample D) as control, this was done by standard procedure using the method of P. Ren, T. Jankun & B. Leaderer. The physical, chemical, and mineral elements from the oil-contaminated soils of the three automobile garages and control. The results of particle soil analysis revealed the high content of sandy soil (96.2 to 87.3) and silt is the lowest with (2.5–0.6). Magnesium had the highest concentration of studied minerals, ranging from 193 to 649.2 mg/kg. while PH result revealed that the soil samples were pH value ranged from (16.85–16.20) in oil Contaminated samples, while the control had 15.90, and electrical conductivity ranged from 12.8–13.8 % and 28 % in control, four fungal isolates Aspergillus sp., Penicillum sp., Mucor sp. and Sporobolomyces sp. were identified based on colonial, sexual and morphological characteristics. These fungal strains can be used in bioremediation process and oil pollution reduction in aquatic ecosystems

Relay selection for multiple access relay channel with decode-forward and analog network coding

This paper presents a relay selection for decode-and-forward based on network coding (DF-NC) and analog-NC protocols in general scheme of cellular network system. In the propose scheme the two source node simultaneously transmit their own information to all the relays as well as the destination node, and then, a single relay i.e. best with a minimum symbol error rate (SER) will be selected to forward the new version of the received signal. Simulation results show that, the DF-NC scheme with considerable performance has exactness over analog-NC scheme. To improve the system performance, optimal power allocation between the two sources and the best relay is determined based on the asymptotic SER. By increasing the number of relays node, the optimum power allocation achieve better performance than asymptotic SER.Comment: 11 pages, 5 figures; International Journal of Distributed and Parallel Systems (IJDPS) Vol.3, No.2, March 201