144 research outputs found

    A New Approach Correlating Binaural Hearing and the Brain’s Response

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    Normal binaural hearing allows the auditory system to determine the direction and distance of sound sources and to detect certain sounds at much lower intensity levels. Different stimuli may have different impact on binaural processing and may generate different brain responses. The mechanism by which this occurs is poorly understood. Time averaged EEG responses of normal hearing subjects to repeated stimuli were analyzed. The stimuli, 500 Hz Blackman windowed pure tones, were presented as homo-phasic or anti-phasic and were also mixed with various noise conditions. Auditory evoked potentials (AEP) were obtained by averaging 500 trials of in-phase and 500 trials of out-phase of each EEG epoch. The results show that the amplitude of the dominant frequency component in the 20 - 50 Hz range of the middle latency response of the AEP was larger for the anti-phasic condition than for the homo-phasic condition. The normalised amplitude differences were larger when the stimuli were embedded in noise resulting in a higher mean value of the normalized amplitude difference than for noise free stimuli. These results are likely to relate to binaural masking level difference which finds that the detection of a signal in a background noise is easier when the signal has a different inter-aural phase difference than the noise

    Proposal for an experiment to search for Randall-Sundrum type corrections to Newton's law of gravitation

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    String theory, as well as the string inspired brane-world models such as the Randall-Sundrum (RS) one, suggest a modification of Newton's law of gravitation at small distance scales. Search for modifications of standard gravity is an active field of research in this context. It is well known that short range corrections to gravity would violate the Newton-Birkhoff theorem. Based on calculations of RS type non-Newtonian forces for finite size spherical bodies, we propose a torsion balance based experiment to search for the effects of violation of this celebrated theorem valid in Newtonian gravity as well as the general theory of relativity. We explain the main principle behind the experiment and provide detailed calculations suggesting optimum values of the parameters of the experiment. The projected sensitivity is sufficient to probe the Randall-Sundrum parameter up to 10 microns.Comment: 4 pages and 5 figures, figures improved, minor clarifications and few references added, final version to appear in PRD (rapid communications

    Security source code analysis of applications in Android OS

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    It is a known fact that Android mobile phones' security has room for improvement. Many malicious app developers have targeted android mobile phones, mainly because android as an open operating system provides great flexibility to developers and there are many android phones which do not have the latest security updates. With the update of marshmallow in android, applications request permission only during runtime, but not all users have this update. This is important because user permission is required to perform certain actions. The permissions may be irrelevant to the features provided by an application. The purpose of this research is to investigate the use and security risk of seeming irrelevant permissions in applications available from Google store. Two different applications which seem to ask irrelevant permissions during installation were selected from Google store. To test these applications, static analysis, dynamic analysis and reverse engineering tools were used. Findings show potentially malicious behavior, demonstrating that downloading apps from Google play store do not guarantee security

    Preventive measures for cross site request forgery attacks on web-based applications

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    Today's contemporary business world has incorporated Web Services and Web Applications in its core of operating cycle nowadays and security plays a major role in the amalgamation of such services and applications with the business needs worldwide. OWASP (Open Web Application Security Project) states that the effectiveness of security mechanisms in a Web Application can be estimated by evaluating the degree of vulnerability against any of the nominated top ten vulnerabilities, nominated by the OWASP. This paper sheds light on a number of existing tools that can be used to test for the CSRF vulnerability. The main objective of the research is to identify the available solutions to prevent CSRF attacks. By analyzing the techniques employed in each of the solutions, the optimal tool can be identified. Tests against the exploitation of the vulnerabilities were conducted after implementing the solutions into the web application to check the efficacy of each of the solutions. The research also proposes a combined solution that integrates the passing of an unpredictable token through a hidden field and validating it on the server side with the passing of token through URL

    Factors associated with the discontinuation of modern methods of contraception in the low income areas of Sukh Initiative Karachi: A community-based case control study

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    Introduction: Discontinuation of a contraceptive method soon after its initiation is becoming a public health problem in Low middle income countries and may result in unintended pregnancy and related unwanted consequences. A better understanding of factors behind discontinuation of a modern method would help in designing interventions to continue its use till desired spacing goals are achieved. |Objective: To determine factors associated with the discontinuation of modern contraceptive methods within six months of its use compared to continued use of modern method for at least six months in low-income areas of Karachi, Pakistan. Method: Community-based case-control study was conducted in low-income areas of Karachi. Cases were 137 users who discontinued a modern contraceptive method within 6 months of initiation and were not using any method at the time of interview, while controls were 276 continuous users of modern method for at least last six months from the time of interview. Information was collected by using a structured questionnaire. Applied logistic regression was used to identify the associated factors for discontinuation. Result: The mean ages of discontinued and continued users were 29.3±5.3 years and 29.2±5.4 years respectively. A larger proportion of the discontinued users had no formal education (43.8%) as compared to the continued users (27.9%). The factors associated with discontinuation of a modern method of contraception were belonging to Sindhi ethnicity [OR: 2.54, 95%CI 1.16-5.57], experiencing side effects [OR: 15.12; 95% CI 7.50-30.51], difficulty in accessing contraceptives by themselves [OR: 0.40, 95%CI 0.19-0.83] and difficulty in reaching clinics for management of the side effects [OR: 4.10, 95%CI 2.38-7.05]. Moreover, women having support from the husband for contraceptive use were less likely to discontinue the method [OR: 0.58, 95% CI 0.34-0.98]. Conclusion: Sindhi ethnicity and side effects of modern methods of contraception were identified as major factors for discontinuation in low-income populations. Similarly, women who had difficulty in travelling to reach clinics for treatment also contributed to discontinuation. Furthermore, women using long acting methods and those supported by their husbands were less likely to discontinue the contraceptive methods. Findings emphasize a need to focus on Sindhi ethnicity and trainings of service providers on management of side effects and provision of high quality of services

    Intrusion detection system for the Internet of Things based on blockchain and multi-agent systems

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    With the popularity of Internet of Things (IoT) technology, the security of the IoT network has become an important issue. Traditional intrusion detection systems have their limitations when applied to the IoT network due to resource constraints and the complexity. This research focusses on the design, implementation and testing of an intrusion detection system which uses a hybrid placement strategy based on a multi-agent system, blockchain and deep learning algorithms. The system consists of the following modules: data collection, data management, analysis, and response. The National security lab–knowledge discovery and data mining NSL-KDD dataset is used to test the system. The results demonstrate the efficiency of deep learning algorithms when detecting attacks from the transport layer. The experiment indicates that deep learning algorithms are suitable for intrusion detection in IoT network environment

    High-energy ball milling technique for ZnO nanoparticles as antibacterial material

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    Nanoparticles of zinc oxide (ZnO) are increasingly recognized for their utility in biological applications. In this study, the high-energy ball milling (HEBM) technique was used to produce nanoparticles of ZnO from its microcrystalline powder. Four samples were ball milled for 2, 10, 20, and 50 hours, respectively. The structural and optical modifications induced in the ‘as synthesized’ nanomaterials were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and photoluminescence emission spectra (PL). SEM and TEM results show a gradual decrease in particle size from around 600 to ∼30 nm, with increased milling time. The initial microstructures had random shapes, while the final shape became quite spherical. XRD analysis showed ZnO in a hexagonal structure, broadening in the diffracted peaks and going from larger to smaller particles along with a relaxation in the lattice constant c. The value of c was found to increase from 5.204 to 5.217 Å with a decrease in particle size (600 to ∼30 nm). PL result showed a new band at around 365 nm, whose intensity is found to increase as the particles size decreases. These remarkable structural and optical modifications induced in ZnO nanoparticles might prove useful for various applications. The increase in c value is an important factor for increasing the antibacterial effects of ZnO, suggesting that the HEBM technique is quite suitable for producing these nanoparticles for this purpose

    Determining the optimal number of GAT and GCN layers for node classification in graph neural networks

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    Node classification in complex networks plays an important role including social network analysis and recommendation systems. Some graph neural networks such as Graph Convolutional Networks (GCN) and Graph Attention Networks (GAT) have emerged as effective approaches for achieving high-performance classification in such tasks. However, constructing a graph neural network architecture is challenging particularly due to the complex task of determining the optimal number of layers. This study presents a mathematical formula for determining the optimal number of GCN and GAT hidden layers. The experiment was conducted on ten benchmark datasets, evaluating performance metrices such as accuracy, precision, recall, F1-score, and MCC for identifying the best estimation of number of hidden layers. According to the experimental findings, the number of GAT and GCN layers selected has a substantial impact on classification accuracy. Studies show that adding extra layers after the optimum number of layers has a negative or no impact on the classification performance. Our proposed approximation technique may provide valuable insights for enhancing efficiency and accuracy of the Graph Neural Network algorithms

    Priority-Based Offloading and Caching in Mobile Edge Cloud

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    Mobile Edge Computing (MEC) is relatively a novel concept in the parlance of Computational Offloading. MEC signifies the offloading of intensive computational tasks to the cloud which is generally positioned at the edge of a mobile network. Being in an embryonic stage of development, not much research has yet been done in this field despite its potential promises. However, with time the advantages are gaining growing attention and MEC is gradually taking over some of the resource-intensive functionalities of a traditional centralized cloud-based system. Another new idea called Task Caching is emerging rapidly with the offloading policy. This joint optimization idea of Task Offloading and caching is relatively a very new concept. It has been in use for reducing energy consumption and delay time for mobile edge computing. Due to the encouraging offshoots from some of the current research on the joint optimization problem, this research initiative aims to take the progress forward. The work improves upon the “prioritization of the tasks” by adopting a very practical approach discussed forward, and proposes a different way for Task Offloading and caching to the edge of the cloud, thereby bringing a significant enhancement to the QoS of MEC
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