On the Verification of a WiMax Design Using Symbolic Simulation

In top-down multi-level design methodologies, design descriptions at higher levels of abstraction are incrementally refined to the final realizations. Simulation based techniques have traditionally been used to verify that such model refinements do not change the design functionality. Unfortunately, with computer simulations it is not possible to completely check that a design transformation is correct in a reasonable amount of time, as the number of test patterns required to do so increase exponentially with the number of system state variables. In this paper, we propose a methodology for the verification of conformance of models generated at higher levels of abstraction in the design process to the design specifications. We model the system behavior using sequence of recurrence equations. We then use symbolic simulation together with equivalence checking and property checking techniques for design verification. Using our proposed method, we have verified the equivalence of three WiMax system models at different levels of design abstraction, and the correctness of various system properties on those models. Our symbolic modeling and verification experiments show that the proposed verification methodology provides performance advantage over its numerical counterpart.Comment: In Proceedings SCSS 2012, arXiv:1307.802

Decoding information for grasping from the macaque dorsomedial visual stream

Neurodecoders have been developed by researchers mostly to control neuroprosthetic devices, but also to shed new light on neural functions. In this study, we show that signals representing grip configurations can be reliably decoded from neural data acquired from area V6A of the monkey medial posterior parietal cortex. Two Macaca fascicularis monkeys were trained to perform an instructed-delay reach-to-grasp task in the dark and in the light toward objects of different shapes. Population neural activity was extracted at various time intervals on vision of the objects, the delay before movement, and grasp execution. This activity was used to train and validate a Bayes classifier used for decoding objects and grip types. Recognition rates were well over chance level for all the epochs analyzed in this study. Furthermore, we detected slightly different decoding accuracies, depending on the task's visual condition. Generalization analysis was performed by training and testing the system during different time intervals. This analysis demonstrated that a change of code occurred during the course of the task. Our classifier was able to discriminate grasp types fairly well in advance with respect to grasping onset. This feature might be important when the timing is critical to send signals to external devices before the movement start. Our results suggest that the neural signals from the dorsomedial visual pathway can be a good substrate to feed neural prostheses for prehensile actions

Accurate tube wall temperature by coupled simulation of a steam cracker convection section

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Situating Learning for Digital Inclusion in the Social Context of Communities

An approach to digital and social inclusion has been developed which situates learning for digital inclusion in the social context of communities. The approach follows views of learning that emphasise the role of the context in learning and the importance of learning in authentic situations. While digital inclusion programs tend to focus more on teaching people how to use computers and the internet, the approach presented takes a different perspective, in which learning for digital inclusion is situated in the social context of the learners and is based on authentic activities. The approach is being applied in Brazilian rural communities

Quality of media traffic over Lossy internet protocol networks: Measurement and improvement.

Voice over Internet Protocol (VoIP) is an active area of research in the world of communication. The high revenue made by the telecommunication companies is a motivation to develop solutions that transmit voice over other media rather than the traditional, circuit switching network. However, while IP networks can carry data traffic very well due to their besteffort nature, they are not designed to carry real-time applications such as voice. As such several degradations can happen to the speech signal before it reaches its destination. Therefore, it is important for legal, commercial, and technical reasons to measure the quality of VoIP applications accurately and non-intrusively. Several methods were proposed to measure the speech quality: some of these methods are subjective, others are intrusive-based while others are non-intrusive. One of the non-intrusive methods for measuring the speech quality is the E-model standardised by the International Telecommunication Union-Telecommunication Standardisation Sector (ITU-T). Although the E-model is a non-intrusive method for measuring the speech quality, but it depends on the time-consuming, expensive and hard to conduct subjective tests to calibrate its parameters, consequently it is applicable to a limited number of conditions and speech coders. Also, it is less accurate than the intrusive methods such as Perceptual Evaluation of Speech Quality (PESQ) because it does not consider the contents of the received signal. In this thesis an approach to extend the E-model based on PESQ is proposed. Using this method the E-model can be extended to new network conditions and applied to new speech coders without the need for the subjective tests. The modified E-model calibrated using PESQ is compared with the E-model calibrated using i ii subjective tests to prove its effectiveness. During the above extension the relation between quality estimation using the E-model and PESQ is investigated and a correction formula is proposed to correct the deviation in speech quality estimation. Another extension to the E-model to improve its accuracy in comparison with the PESQ looks into the content of the degraded signal and classifies packet loss into either Voiced or Unvoiced based on the received surrounding packets. The accuracy of the proposed method is evaluated by comparing the estimation of the new method that takes packet class into consideration with the measurement provided by PESQ as a more accurate, intrusive method for measuring the speech quality. The above two extensions for quality estimation of the E-model are combined to offer a method for estimating the quality of VoIP applications accurately, nonintrusively without the need for the time-consuming, expensive, and hard to conduct subjective tests. Finally, the applicability of the E-model or the modified E-model in measuring the quality of services in Service Oriented Computing (SOC) is illustrated

Tales from the Levant: The Judeo-Arabic Demonic ‘Other’ and John Milton’s Paradise Lost

This thesis revisits Milton’s employment of mythology and the demonic, by shedding a light on a neglected, yet intriguing possible presence of Middle-Eastern mythology – or as identified in this thesis – Judeo-Arabic mythology in Paradise Lost. The mythographic reception of Milton’s work has been rightly discussed within a Greco-Roman frame. However, this thesis offers for a consideration an analysis of the unique role of Judeo-Arabic mythology. By doing so, the thesis not only aims to enrich the dualistic analyses of ‘East-West’, ‘Christian-Muslim’ and ‘Anglo-Ottoman’ relations, when tackling this angle of Early Modern studies, but also to generally demonstrate the way seventeenth-century literature encompassed multifaceted and interchangeable allusions to both Islam and Judaism in Catholic and Protestant writing. The thesis directs its attention towards examining the possible presence of two Judeo-Arabic demonic figures in Paradise Lost: the Islamic devil, Iblis, and his consort in the Jewish tradition, Lilith. The argument demonstrates the way Milton’s deployment of the Judeo-Arabic demonic not only mirrors the Biblical story of the Fall, but also connects with the political and religious upheavals of his age, including the emergence of the first English translation of the Qur’an in 1649. Furthermore, by examining the two Judeo-Arabic demonic figures in Paradise Lost not only the treatment of the demonic in Milton’s work is revisited in a way that allows for a wider scope of literary analysis, but the complex treatment of gender, identity and ‘the Other’ are similarly understood within a more pluralistic context. The thesis then concludes with the first discussion of the contemporary reception of Milton’s Paradise Lost in the writings of Arab women specifically, exploring the way the very same demonic, discussed throughout the thesis, is deployed by these female Arab authors while resisting and redefining the role of gender in religion, society and politics

VoIP Quality Assessment Technologies

Non

Securing Smart Grid Communication Using Ethereum Smart Contracts

Haidar Safa Mohamed NassarSmart grids are being continually adopted as a replacement of the traditional power grid systems to ensure safe, efficient, and cost-effective power distribution. The smart grid is a heterogeneous communication network made up of various devices and components such as smart meters, automation, and emerging technologies interacting with each other. As a result, the smart grid inherits most of the security vulnerabilities of cyber systems, putting the smart grid at risk of cyber-attacks. To secure the communication between smart grid entities, namely the smart meters and the utility, we propose in this thesis a communication infrastructure built on top of a blockchain network, specifically Ethereum. All two-way communication between the smart meters and the utility is assumed to be transactions governed by smart contracts. Smart contracts are designed in such a way to ensure that each smart meter is authentic and each smart meter reading is reported securely and privately. We present a simulation of a sample smart grid and report the costs incurred from building such a grid. Each architecture discussed will contain a solution to a problem previously faced and will come with trade-offs that are analyzed in terms of certain metrics. The simulations illustrate the feasibility and security of the proposed architectures

WSN-DS: A Dataset for Intrusion Detection Systems in Wireless Sensor Networks

Wireless Sensor Networks (WSN) have become increasingly one of the hottest research areas in computer science due to their wide range of applications including critical military and civilian applications. Such applications have created various security threats, especially in unattended environments. To ensure the security and dependability of WSN services, an Intrusion Detection System (IDS) should be in place. This IDS has to be compatible with the characteristics of WSNs and capable of detecting the largest possible number of security threats. In this paper a specialized dataset for WSN is developed to help better detect and classify four types of Denial of Service (DoS) attacks: Blackhole, Grayhole, Flooding, and Scheduling attacks. This paper considers the use of LEACH protocol which is one of the most popular hierarchical routing protocols in WSNs. A scheme has been defined to collect data from Network Simulator 2 (NS-2) and then processed to produce 23 features. The collected dataset is called WSN-DS. Artificial Neural Network (ANN) has been trained on the dataset to detect and classify different DoS attacks. The results show that WSN-DS improved the ability of IDS to achieve higher classification accuracy rate. WEKA toolbox was used with holdout and 10-Fold Cross Validation methods. The best results were achieved with 10-Fold Cross Validation with one hidden layer. The classification accuracies of attacks were 92.8%, 99.4%, 92.2%, 75.6%, and 99.8% for Blackhole, Flooding, Scheduling, and Grayhole attacks, in addition to the normal case (without attacks), respectively