No abstract

Centralized file-sharing networks have low reliability, scalability issues, and possess a single point of failure, thus making peer-to-peer (P2P) networks an attractive alternative since they are mostly anonymous, autonomous, cooperative, and decentralized. Although, there are review articles on P2P overlay networks and technologies, however, other aspects such as hybrid P2P networks, modelling of P2P, trust and reputation management issues, coexistence with other existing networks, and so on have not been comprehensively reviewed. In addition, existing reviews were limited to articles published in or before 2012. This paper performs a state-of-the-art literature survey on the emerging research areas of P2P networks, applications and ensuing challenges along with proposed solutions by scholars. The literature search for this survey was limited to the top-rated publisher of scholarly articles. This research shows that issues with security, privacy, the confidentiality of information and trust management will need greater attention, especially in sensitive applications like health services and vehicle to vehicle communication ad hoc networks. In addition, more work is needed in developing solutions to effectively investigate and curb deviant behaviours among some P2P networks.

Abstract-properties of Silicon Carbide Junction Field EffectTransistor (SiC JFET) such as high switching speed, low forward voltage drop and high temperature operation have attracted the interest of power electronic researchers and technologists, who for many years developed devices based on Silicon (Si). A number of power system Engineers have made efforts to develop more robust equipment including circuits or modules with higher power density. However, it was realized that several available power semiconductor devices were approaching theoretical limits offered by Si material with respect to capability to block high voltage, provide low on-state voltage drop and switch at high frequencies. This paper presents an overview of the current applications of SiC JFET in circuits such as inverters, rectifiers and amplifiers. Other areas of application reviewed include; usage of the SiC JFET in pulse signal circuits and boost converters. Efforts directed toward mitigating the observed increase in electromagnetic interference were also discussed. It also presented some areas for further research, such as having more applications of SiC JFET in harsh, high temperature environment. More work is needed with regards to SiC JFET drivers so as to ensure stable and reliable operation, and reduction in the prices of SiC JFETs through mass production by industries.

This paper focuses on the design and implementation of an automated pricing system using international breweries Ilesha as a case study. The research makes a provision for the customization of the program designs in order to accommodate other manufacturing company such as Cadbury, Unilever, Nigeria breweries, Nestle etc. The objectives include reduction of stress, paper work and error, also to increase speed and satisfy customers. The research work proffer a solution to a competitive price changes and assists enterprise on how to quickly respond to price change. This gives rooms for easy & quick price adjustment. In order to achieve all these, design and implementation of an automated pricing system is necessary. This paper presents the design of a web based application called Price Engine by making use of PHP, MySQL, Apache, Dreamweaver, and HTML as design tools.

DC motor as an electric machine have been applied in numerous control systems. However, a critical parameter of interest that must be evaluated in designing a DC motor based system is the damping constant of the rotor. This paper analytically examines how to determine the damping constant of the rotor of a 12V DC motor, with the determination based on the following parameters: Armature resistance (R a), inductance (La), Capacitance, the Stall current and the Angular rate of excitation of the motor with varying armature excitation of the current. These parameters help to ascertain the maximum and the minimum operating limit of the motor so as not to exceed the boundary-operating limits of the 12V motor. Experiments were performed in the laboratory and at the end of the analysis, the result shows that the value of damping constant of a 12V DC motor was-3.317  10-4 N-m-sec 2. This parameter can be factored in future control system designs.