1,010 research outputs found
On the practical utility of a continuum traffic flow model on curvy highways in adverse weather conditions
No full textThe macroscopic continuum traffic flow models are being investigated to predict and ameliorate traffic more efficiently. These models are beneficial implementation tools to comprehend and complement the shortfalls in traffic evolution. Despite the significant enhancements in devising the traffic dynamics, the practical utilization of these macroscopic models is not being fully explored. In this study, the Non-Homogeneous Stimulus-Response Model (NHSRM) (Imran et al., 2023) is investigated for its application in forecasting traffic flow on a curvy highway during various weather conditions. The weather impact, in the specific, dry, light rainfall, moderate rainfall, and heavy rainfall on the travel time, velocity, and density spatiotemporal evolution on a curvy highway is analyzed. The flow during different weather conditions is investigated over two curved roads with 120 m, and 500 m radii. As evident from the results, significant velocity breakdowns during heavy rainfall impact the upstream traffic which contributes to congestion development. The average velocity of traffic depletes significantly, and the congestion formation upstream is significant. While the travel time of particular highway segments elevates sharply during heavy rainfall. A comprehensive understanding of the insights, and the critically associated with the parameters of the model, in particular, on the choice of the maximum velocity of the highway has been presented for NHSRM
Interview with Bashir Omar
No full textهذة المقابلة مع المؤلف بشير عمر، يتحدث عن مؤلفاتة وخاصة كتب الأطفال، كما أشار لمشكلة الكتابة المتعلقة بكتب الأطفال وكيفية حلها.أجرى المقابلة حسن شمس الدين.In this interview, author Bashir Omar (Bashir Umar) speaks about his writings. He also mentions difficulties in writing children's books and how to resolve them. The interview was conducted by Hasan Shams al-Din
Design and testing of a sensing system for aero-engine smart bearings
No full textSmart bearings incorporating self-powered sensors and wireless data communications with intelligence in monitoring bearing conditions can help to detect early faults in aero-engine bearings. This paper presents the challenges in design and development of a sensing system with compact and low-power consumption sensors and the procedures for sensor performance evaluation under the requirements of aerospace standard (DO160 [1]). Industrial standard DO160 testing is necessary for preliminary testing of the smart sensing system prior to being installed in aero-engine, thus a laboratory test procedure has been developed for sensor performance evaluation for the smart aero-engine bearings in this project. As a case study, this paper presents the details and results of the accelerometer evaluation following the requirements in DO160
Calculating trust using multiple heterogeneous social networks
No full textIn today's Internet, a web user becomes members of multiple social networks due to different types of services provided by each of these networks. This creates an opportunity to make trust decisions that go beyond individual social networks, since these networks provide single perspective of trust. To make trust inference over multiple social networks, these networks need to be consolidated. It is nontrivial as these networks are of heterogeneous nature due to different naming conventions used in these networks. Furthermore, trust metrics extracted from these networks are also varied in nature due to different trust evaluation algorithms used in each of these networks. Heterogeneity of these social networks can be overcome by using semantic technologies as it allows us to represent knowledge using ontologies. Trust data can be consolidated by using such data fusion techniques which not only provide but also preserve trust data integrity from each of the individual social network profiles. The proposed semantic framework is evaluated using two sets of experiments. Through simulations in this work, we analysed various techniques for data fusion. For identifying suitable technique that preserves the integrity of trust consolidated from each of the individual networks, analysis revealed that Weighted Ordered Weighted Averaging parameter best aggregated trust data, and, unlike other techniques, it preserved the integrity of trust from each individual network for varying participant overlap and tie overlap (p≤0.05). Similarly, for experimental analysis, we used findings of the simulation study about the best trust aggregation technique and applied the proposed framework on real-life trust data between participants, which we extracted from pairs of professional social networks. Analysis partially proved our hypothesis about generating better trust values from consolidated multiple heterogeneous networks. We witnessed an improvement in overall results for all the participants who were part of multiple social networks (p≤0.05), while disproving the claim for those existing in nonoverlapping regions of the social networks.</p
Integrated smart bearings for next generation aero-engines.: Part II: energy harvesting and wireless communication development
No full textThe robust and reliable operation of aircraft engines is paramount. Rolling element bearings play a major role in aircraft engines and bearing failure impacts engine health and reliability. Condition monitoring of the bearing system is necessary to provide early warning of problems by sensing parameters such as vibration and temperature. However, conventional wired sensing systems are not always desirable due to size and weight constraints, and their reduced performance in high temperature and pressure environments. For the development of innovative smart bearings for an Ultra High Propulsion Efficiency (UHPE) ground test demonstrator, an integrated, self-powered and wireless system is proposed. In this paper, the feasibility of using a self-powered sensor for this application is investigated. The design of the self-powered condition monitoring system addresses the issues of both achieving reliable sources of energy and transmitting data. Laboratory experiments are carried out to evaluate the performance of the system under various operating conditions. The effects of temperature variation on efficiency of the energy harvester are demonstrated
Interview with Abd al-Razzaq al-Bashir
No full textهذة المقابلة مع عبد الرزاق البصير الكاتب الكويتي ، وعضو في مجمع اللغة العربية في القاهرة ، يتحدث عن نشأتة وتعليمه. يشير للشعراء المفضلين له، الذين أثروا في شخصيته. ويشير إلى أهمية اللغة العربية في حياته. أجرى المقابلة حسن شمس الدين.In this interview, Kuwaiti author Abd al-Razzaq al-Bashir speaks about his early life and education. He mentions his favorite poets that impacted his life and the importance of the Arabic language. The interview was conducted by Hasan Shams al-Din
First person – Aushaq Bashir Malla
No full textABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Aushaq Bashir Malla is co-first author on ‘ IP6K1 is essential for chromatoid body formation and temporal regulation of Tnp2 and Prm2 expression in mouse spermatids’, published in Journal of Cell Science. Aushaq is a PhD student at the Centre for DNA Fingerprinting and Diagnostics, India, investigating the post-transcriptional regulation of mRNA and role of RNA–protein interactions in disease and development.</jats:p
Application of Analog Adaptive Filters for Dynamic Sensor Compensation
No full textThis paper investigates the application of analog adaptive techniques to the area of dynamic sensor compensation, of which there is little reported work in the literature. The case is illustrated by showing how the response of a load cell can be improved to speed up the process of measurement. The load cell is a sensor with an oscillatory output in which the measurand contributes to the response parameters. Thus, a compensation filter needs to track variation in measurand whereas a simple, fixed filter is only valid at one specific load value. To facilitate this investigation, computer models for the load cell and the adaptive compensation filter have been developed. To allow a practical implementation of the adaptive techniques, a novel piecewise linearization technique is proposed in order to vary a floating voltage-controlled resistor in a linear manner over a wide range. Simulation and practical results are presented, thus demonstrating the effectiveness of the proposed techniques
A Fast and Accurate Process Variation-aware Modeling Technique for Resistive Bridge Defects
No full textRecent research has shown that tests generated without taking process variation into account may lead to loss of test quality. At present there is no efficient device-level modeling technique that models the effect of process variation on resistive bridge defects. This paper presents a fast and accurate technique to achieve this, including modeling the effect of voltage and temperature variation using BSIM4 transistor model. To speedup the computation time and without compromising simulation accuracy (achieved through BSIM4) two efficient voltage approximation algorithms are proposed for calculating logic threshold of driven gates and voltages on bridged lines of a fault-site to calculate bridge critical resistance. Experiments are conducted on a 65-nm gate library (for illustration purposes), and results show that on average the proposed modeling technique is more than 53 times faster and in the worst case, error in bridge critical resistance is 2.64% when compared with HSPICE
Oil-cooled thermoelectric energy harvesting for aero-engine sensing system
No full textTo enhance the performance and reliability of aircraft propulsion systems, an integrated bearing condition monitoring system is proposed. This intelligent bearing must have advanced health management capabilities to provide early warning of problems. In most commercial high-temperature applications, the sensing system is located externally due to lack of appropriate electronic devices that can function at high temperature. This paper presents the design and implementation of a self-powered sensing system for use in a high-temperature aircraft environment. The performance of the thermoelectric generator and energy availability to process acceleration data is shown from our laboratory tests based on realistic operating conditions
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