| 1. |
- Ali, Amjad, et al.
(författare)
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Electrochemical study of composite materials for coal-based direct carbon fuel cell
- 2018
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 43:28, s. 12900-12908
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Tidskriftsartikel (refereegranskat)abstract
- The efficient conversion of solid carbon fuels into energy by reducing the emission of harmful gases is important for clean environment. In this regards, direct carbon fuel cell (DCFC) is a system that converts solid carbon directly into electrical energy with high thermodynamic efficiency (100%), system efficiency of 80% and half emission of gases compared to conventional coal power plants. This can generate electricity from any carbonaceous fuel such as charcoal, carbon black, carbon fiber, graphite, lignite, bituminous coal and waste materials. In this paper, ternary carbonate-samarium doped ceria (LNK-SDC) electrolyte has been synthesized via co-precipitation technique, while LiNi-CuZnFeO (LNCZFO) electrode has been prepared using solid state reaction method. Due to significant ionic conductivity of electrolyte LNK-SDC, it is used in DCFC. Three types of solid carbon (lignite, bituminous, sub-bituminous) are used as fuel to generate power. The X-ray diffraction confirmed the cubic crystalline structure of samarium doped ceria, whereas XRD pattern of LNCZFO showed its composite structure. The proximate and ultimate coal analysis showed that fuel (carbon) with higher carbon content and lower ash content was promising fuel for DCFC. The measured ionic conductivity of LNK-SDC is 0.0998 Scm(-1) and electronic conductivity of LNCZFO is 10.1 Scm(-1) at 700 degrees C, respectively. A maximum power density of 58 mWcm(-2) is obtained using sub bituminous fuel.
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| 2. |
- Ali, Irfan, et al.
(författare)
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A thermal-aware scheduling algorithm for reducing thermal risks in DAG-based applications in cyber-physical systems
- 2023
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Ingår i: Ubiquitous security. - Singapore : Springer. - 9789819902712 - 9789819902729 ; , s. 497-508
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Konferensbidrag (refereegranskat)abstract
- Directed Acyclic Graph (DAG)-based scheduling applications are critical to resource allocation in the Cloud, Edge, and Fog layers of cyber-physical systems (CPS). However, thermal anomalies in DVFS-enabled homogeneous multiprocessor systems (HMSS) may be exploited by malicious applications posing risks to the availability of the underlying CPS. This can negatively affect the trustworthiness of CPS. This paper proposes an algorithm to address the thermal risks in DVFS-enabled HMSS for periodic DAG-based applications. It also improves the current list scheduling-based Depth-First and Breadth-First techniques without violating the timing constraints of the system. We test the algorithm using standard benchmarks and synthetic applications in a simulation setup. The results show a reduction in the temperature peaks by up to 30%, average temperature by up to 22%, temperature variations up to 3 times, and temperature spatial gradients by up to 4 times as compared to the conventional Depth-First Scheduling algorithms.
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| 3. |
- Ashraf, Shehzad Ali, et al.
(författare)
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From Radio Design to System Evaluations for Ultra-Reliable and Low-Latency Communication
- 2017
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Ingår i: European Wireless 2017 - 23rd European Wireless Conference. - 9783800744268
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Konferensbidrag (refereegranskat)abstract
- Ultra-reliable and low-latency communication is the enabler for many new use cases, including wireless industrial automation. Fulfilling varying requirements of these use cases demands a flexible radio design. To address this, a holistic approach needs to be adopted. Therefore, this paper presents the radio access concepts affecting the communication reliability and latency, and comprehensively evaluates link and system level considerations through simulations. In particular, we describe the choice of suitable modulation and coding schemes, and discuss the impact of different numerologies and waveform candidates. We also point out the key principles for radio frame design to reduce the end-to-end latency. The presented concepts are then used to evaluate the performance at system level for an industrial scenario. It is shown that by an appropriate design of the radio interface for 5G system, the required low-latency and high reliability for industrial applications and many other use cases can be achieved.
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| 4. |
- Cheema, M. A., et al.
(författare)
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A Drone-Aided Blockchain-Based Smart Vehicular Network
- 2021
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Ingår i: IEEE transactions on intelligent transportation systems (Print). - : Institute of Electrical and Electronics Engineers Inc.. - 1524-9050 .- 1558-0016. ; 22:7, s. 4160-4170
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Tidskriftsartikel (refereegranskat)abstract
- The staggering growth of the number of vehicles worldwide has become a critical challenge resulting in tragic incidents, environment pollution, congestion, etc. Therefore, one of the promising approaches is to design a smart vehicular system as it is beneficial to drive safely. Present vehicular system lacks data reliability, security, and easy deployment. Motivated by these issues, this paper addresses a drone-enabled intelligent vehicular system, which is secure, easy to deploy and reliable in quality. Nevertheless, an increase in the number of operating drones in the communication networks makes them more vulnerable towards the cyber-attacks, which can completely sabotage the communication infrastructure. To tackle these problems, we propose a blockchain-based registration and authentication system for the entities such as drones, smart vehicles (SVs) and roadside units (RSUs). This paper is mainly focused on the blockchain-based secure system design and the optimal placement of drones to improve the spectral efficiency of the overall network. In particular, we investigate the association of RSUs with the drones by considering multiple communication-related factors such as available bandwidth, maximum number of links a drone can support, and backhaul limitations. We show that the proposed model can easily be overlaid on the current vehicular network reaping benefits of secure and reliable communications. © 2000-2011 IEEE.
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| 5. |
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| 6. |
- Shehzad, Muhammad Karam, et al.
(författare)
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On the Association of Small Cell Base Stations with UAVs using Unsupervised Learning
- 2019
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Ingår i: IEEE 89th Vehicular Technology Conference, VTC2019-Spring. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Small cell networks (SCNs) offer a cost-effective coverage solution to wireless applications demanding high data rates. However in SCNs, a challenging problem is the proper management of backhaul links to small cell base stations(SCBSs). To make a good backhaul link, perfect line-of-sight (LoS) communication between the SCBSs and the core network plays a vital role. In this study, we use the idea of employing unmanned aerial vehicles (UAVs) to provide connectivity betweenSCBSs and the core network. We focus on the association of SCBSs with UAVs by considering multiple communication-related factors including data rate limit and available bandwidth resources of the backhaul. In particular, we address the optimum placement of UAVs to serve a maximum number of SCBSswhile considering available resources using the unsupervised k-means algorithm. Numerical results show that the proposed approach outperforms the conventional approach in terms of associatedSCBSs, bandwidth consumption, available link utilization, and sum-rate maximization.
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