23 research outputs found

    BAS-VAS: A novel secure protocol for value added service delivery to mobile devices

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    Mobile operators offer a wide range of valueadded services (VAS) to their subscribers (i.e., mobile users), which in turn generates around 15% of the telecommunication industry revenue. However, simultaneous VAS requests from a large number of mobile devices to a single server or a cluster in an internet-of-things (IoT) environment could result in an inefficient system, if these requests are handled one at a time as the present traditional cellular network scenario is. This will not only slow down the server’s efficiency but also adversely impacts the performance of the network. The current (insecure) practice of transmitting user identity in plaintext also results in traceability. In this paper, we introduce the first known protocol designed to efficiently handle multiple VAS requests at one time, as well as ensuring the secure delivery of the services to a large number of requesting mobile users. The proposed batch verification protocol (BAS-VAS) is capable of authenticating multiple simultaneous requests received by a large number of mobile users. We demonstrate that the protocol preserves user privacy over the network. The provider’s servers ensure the privacy of the requested service’s priority by performing sorting over encrypted integer data. The simulation results also demonstrate that the proposed protocol is lightweight and efficient in terms of communication and computation overheads, protocol execution time, and batch and re-batch verification delay. Specifically, we perform batch and re-batch verification (after detecting and removing malicious requests from the batch) for multiple requests in order to improve the overall efficiency of the system, as well as discussing time, space and cost complexity analysis, along with the security proof of our protocol using Proverif

    Development of an Adaptive Environmental Management System for Lejweleputswa District: A Participatory Approach through Fuzzy Cognitive Maps

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    Published ThesisEnvironmental pollution caused by mines within the district of Lejweleputswa in Free State is a major contributor to health issues and the inability to grow crops within the mining communities. Mining industries continue to develop environmental management systems/plans to mitigate the impact their operations has on the society. Even with these plans, there are still issues of environmental pollution affecting the society. Though there are Information Communication and Technology (ICT) based pollution monitoring solutions, their use is dismal due to lack of appreciation or understanding of how they disseminate information. Furthermore, non-adopting community members are being regarded as inherently conservative or irrational, but these community members argue that the recommendations and technologies brought to them are not always appropriate to their circumstances. There was concern that local people’s knowledge of their environment, farming systems, and their social as well as economic situation had been ignored and underestimated when ICTs solutions are being implemented (Warburton & Martin, 1999). Another challenge is that there is no station to monitor pollution for small communities such as Nyakallong in the district. This result in mining communities depending on their own local knowledge to observe and monitor mining related environmental pollution. However, this local knowledge has never been tested scientifically or analysed to recognize its usability or effectiveness. Mining companies tend to ignore this knowledge from the communities as it is treated like common information with no much scientific value. As a step towards verifying or validating this local knowledge, fuzzy cognitive maps were used to model, analyse and represent this linguistic local knowledge. Although this local knowledge assists in mitigating environmental pollution, incorporating it with scientific knowledge will improve its relevance, trustworthiness and acceptability by majority of community members and policy-makers. Information and Communication Technologies (ICTs) can accelerate this integration; this is the focus of this research. The increased usages of Information Technology being witnessed today makes it the most important factor for the world to depend on for solutions to many of today’s and tomorrow’s problems. These solutions make use of various forms for dissemination purposes, one of the most versatile dissemination device is a mobile phone since majority of the world’s population do own a mobile phone. In this way information is easily accessible by almost everyone that needs it. A novel environmental management solution was designed to work within the mining communities of Lejweleputswa. The research started off by designing a unique integration framework that creates the much-needed link between local knowledge and scientific knowledge. The framework was then converted into an adaptable environmental pollution management system prototype made up of three components; (1) gathering environmental pollution knowledge; (2) environmental monitoring and; (3) environmental dissemination and communication. To achieve sustainability, relevance and acceptability, local knowledge was integrated in each of the three components while mobile phones were used as both input and output devices for the system. In order to facilitate collection and conservation of local knowledge on environmental monitoring, an elaborate android-based mobile application was developed. Wireless sensor-based gas sensor boards were acquired, and deployed as a compliment to conventional monitoring stations, they were used to gather scientific knowledge. To allow for public access to the system’s data, a web portal and an SMS-based component were also implemented. In order to collect local knowledge from community, a case study of Nyakallong community in Lejweleputswa was carried out. On completion of the system prototype, it was evaluated by participants from the community; 90% of respondents gave a score of ‘excellent ‘

    A Review of Resonant Converter Control Techniques and The Performances

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    paper first discusses each control technique and then gives experimental results and/or performance to highlights their merits. The resonant converter used as a case study is not specified to just single topology instead it used few topologies such as series-parallel resonant converter (SPRC), LCC resonant converter and parallel resonant converter (PRC). On the other hand, the control techniques presented in this paper are self-sustained phase shift modulation (SSPSM) control, self-oscillating power factor control, magnetic control and the H-∞ robust control technique

    State-Feedback Controller Based on Pole Placement Technique for Inverted Pendulum System

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    This paper presents a state space control technique for inverted pendulum system using simulation and real experiment via MATLAB/SIMULINK software. The inverted pendulum is difficult system to control in the field of control engineering. It is also one of the most important classical control system problems because of its nonlinear characteristics and unstable system. It has three main problems that always appear in control application which are nonlinear system, unstable and non-minimumbehavior phase system. This project will apply state feedback controller based on pole placement technique which is capable in stabilizing the practical based inverted pendulum at vertical position. Desired design specifications which are 4 seconds settling time and 5 % overshoot is needed to apply in full state feedback controller based on pole placement technique. First of all, the mathematical model of an inverted pendulum system is derived to obtain the state space representation of the system. Then, the design phase of the State-Feedback Controller can be conducted after linearization technique is performed to the nonlinear equation with the aid of mathematical aided software such as Mathcad. After that, the design is simulated using MATLAB/Simulink software. The controller design of the inverted pendulum system is verified using simulation and experiment test. Finally the controller design is compared with PID controller for benchmarking purpose

    A SIMULATION STUDY OF STATE-FEEDBACK CONTROL METHOD FOR ELECTRO HYDRAULIC SERVO MODEL

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    Electro hydraulic servo system is used by many industries due to its ability to impart large forces. It also has advantage in term of fast response and robustness. The electro hydraulic system suffered from errors of the transient response which are steady state error, settling time and the ripples. It is crucial to design a controller for the system to ensure the reliability of the system. Aiming at the characteristic of the system, steady state feedback control method is designed to compensate the error. The analysis of the system is done based on the transient response specifically on the actuator part. MATLAB Simulink is used as the simulation software to evaluate the force performance of state feedback controller method. The steady state error, settling time and ripple are observed and recorded for each controller. Three methods is applied, which are full feedback, state feedback with feed forward and integral control are compared with proportional, integral and derivatives (PID) controller. The result of each controller shows the differences performance. Based on the simulation results, the feedforward technique is found to be the best control technique for the electro hydraulic servo system due to the requirement performance such as percent overshoot, settling time, rise time and zero steady state error. This good result will directly benefit industries that use electro hydraulic system as their actuator for production machines
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