1,722,495 research outputs found
Simulation based topology optimization assessment with manufacturing constraints
Full text linkIn Automotive and Aerospace industries, Topology Optimization (TO) is being used for the last few decades to produce lightweight structures. On the other hand, TO produces very complex geometrical features (i.e. irregular shape and hidden cavities along the thickness) that is sometimes difficult to be manufactured even with Additive Manufacturing (AM) and Casting techniques. In this paper suitable design and manufacturing constraint (MC) are applied during TO process that act as an Optimization Tool (OT) and improves geometrical features of the mechanical structures for easy manufacturing. Three mechanical structures with different geometries and boundary conditions have been considered for analysis purpose. Topology Optimization based on linear static analysis has been performed using OptiStruct (HyperWorks) solver. Finally, results of analysis conclude that the proposed OT produces lightweight structures with very simple geometries that can easily be manufactured with the help of AM or Casting techniques
A new variant of Jensen inclusion and Hermite-Hadamard type inclusions for interval-valued functions
Full text linkIn this research, we give a new version of Jensen inclusion for interval-valued functions, which is called Jensen-Mercer inclusion. Moreover, we establish some new inclusions of the Hermite-Hadamard-Mercer type for interval-valued functions. Finally, we give some applications of newly established inequalities to make them more interesting for the readers. © 2023, University of Nis. All rights reserved.Suan Dusit University, SDU: N42A650384; National Natural Science Foundation of China, NSFC: 11971241; National Research Council of Thailand, NRCT2020 Mathematics Subject Classification. 26D10, 26A51, 26D15. Keywords. Hermite–Hadamard inequality; Jensen-inequality; Convex interval-valued functions. Received: 15 July 2022; Accepted: 21 December 2022 Communicated by Dragan S. Djordjevi? This project is funded by National Research Council of Thailand (NRCT) and Suan Dusit University: N42A650384. This research was also partially supported by National Natural Science Foundation of China 11971241. * Corresponding author: Muhammad Aamir Ali Email addresses: thanin [email protected] (Thanin Sitthiwirattham), [email protected] (Ifra Bashir Sial), [email protected] (Muhammad Aamir Ali), [email protected] (Hüseyin Budak), [email protected] (Jiraporn Reunsumrit
Design of a non-isolated single phase online ups topology with parallel battery bank for low power applications / Muhammad Aamir
Full text linkUninterruptible Power Supplies (UPS) are widely used to provide reliable and high quality power to critical loads such as airlines computers, datacenters, communication systems, and medical support systems in hospitals in all grid conditions. Online UPS system is considered to be the most preferable UPS due to its highest level of power quality and proven reliability against all types of line disturbances and power outages. This research presents a new topology of the non-isolated online uninterruptible power supply system. The proposed system consists of bridgeless boost rectifier, battery charger/discharger, and an inverter. The rectifier performs power factor correction and provides regulated DC-link voltage. The rectifier operates with a minimum semiconductor device, reducing the conduction losses of the circuit significantly. A new battery charger/discharger has been implemented, which ensures the bidirectional power flow between the DC-link and the battery bank, reducing the battery bank voltage to only 24V, and regulates the DC-link voltage during battery mode. The bidirectional operation of the converter is achieved by employing only three active switches, a coupled inductor, and an additional voltage clamped circuit. Batteries are connected in parallel depending on the backup time requirement of the system. Operating batteries in parallel improve the battery performance and resolve the problems related to conventional battery banks that arrange batteries in series. The inverter provides a regulated output voltage to the load. A new cascaded slide mode and proportional-resonant control have been proposed. Slide mode control is recognized as the most robust control with high stability while the proportional-resonant control shapes the output waveform closely according to the reference sinusoidal signal. Keeping in view the characteristics of slide mode and proportional-resonant control, a cascaded controller is proposed for the bipolar single-phase UPS inverter. The outer voltage loop uses the proportional-resonant control while the inner loop uses the slide mode control. The proposed control scheme regulates the output voltage for both linear and non-linear load and shows excellent performance during transients and step changes in load. The proposed controller shows significant improvement in terms of reducing the total harmonics distortion to 0.5% for linear load and 1.25% for non-linear load, strong robustness, and fast response time of only 0.3ms. Operation principle and experimental results of 1kVA prototype have been presented to verify the validity of the proposed UPS. The efficiency of the proposed system is 94% during battery mode and 92% during the normal mode of operation
Supplemental Material - Actions for solutions: Financial behaviors, power (im)balance, and economic abuse among Chinese young adults in non-marital cohabitation
No full textSupplemental Material for Actions for solutions: Financial behaviors, power (im)balance, and economic abuse among Chinese young adults in non-marital cohabitation by Xiaomin Li, Muhammad Aamir Khan, Jing Jian Xiao and Dexia Kong in Journal of Social and Personal Relationships</p
Çizge uygulamaları için karalama defteri belleği tabanlı özelleştirilmiş işlemci mimarisi analizi
No full textCataloged from PDF version of article.Includes bibliographical references (leaves 64-69).In graph analytic applications, main memory accesses prove to be a bottleneck as
graphs have a poor spatial and temporal locality usage in the caches and higher
memory hierarchy. Although this bottleneck is slightly mitigated with the use
of miss status handling registers (MSHRs) in caches, the problem becomes more
signi cant in the case of large graphs. The MSHR, which relies on an out-of-order
processor's reorder buffer, becomes quickly saturated as the memory requests keep
on piling up because of the limited instruction window size.
To tackle the memory bottleneck for graph applications, the use of a Scratchpad
Memory (SPM) together with custom instructions is proposed. This model
is implemented and tested on a custom in-order processor using the x86 architecture
to accommodate the related custom instructions. The custom instructions
provide non-blocking access to data from the main memory while overlapping
with other non-blocking instructions in the CPU pipeline.
This design is evaluated on an industry-level simulator, GEM5, and uses the
graph kernels from the GAP Benchmark to test the proposed system. The system
shows a speedup of up to 7x for PageRank while averaging a speedup of
1.5x for the other graph kernels such as Single-Source shortest path, Connected
Components, and Triangle Counting.by Muhammad Aamir Saee
Collective Asynchronous Remote Invocation (CARI): A High-Level and Effcient Communication API for Irregular Applications
Full text linkThe Message Passing Interface (MPI) standard continues to dominate the landscape of parallel computing as the de facto API for writing large-scale scientific applications. But the critics argue that it is a low-level API and harder to practice than shared memory approaches. This paper addresses the issue of programming productivity by proposing a high-level, easy-to-use, and effcient programming API that hides and segregates complex low-level message passing code from the application specific code. Our proposed API is inspired by communication patterns found in Gadget-2, which is an MPI-based parallel production code for cosmological N-body and hydrodynamic simulations. In this paper—we analyze Gadget-2 with a view to understanding what high-level Single Program Multiple Data (SPMD) communication abstractions might be developed to replace the intricate use of MPI in such an irregular application—and do so without compromising the effciency. Our analysis revealed that the use of low-level MPI primitives—bundled with the computation code—makes Gadget-2 diffcult to understand and probably hard to maintain. In addition, we found out that the original Gadget-2 code contains a small handful of—complex and recurring—patterns of message passing. We also noted that these complex patterns can be reorganized into a higherlevel communication library with some modifications to the Gadget-2 code. We present the implementation and evaluation of one such message passing pattern (or schedule) that we term Collective Asynchronous Remote Invocation (CARI). As the name suggests, CARI is a collective variant of Remote Method Invocation (RMI), which is an attractive, high-level, and established paradigm in distributed systems programming. The CARI API might be implemented in several ways—we develop and evaluate two versions of this API on a compute cluster. The performance evaluation reveals that CARI versions of the Gadget-2 code perform as well as the original Gadget-2 code but the level of abstraction is raised considerably
On some new quantum midpoint-type inequalities for twice quantum differentiable convex functions
Full text linkThe present paper aims to find some new midpoint-type inequalities for twice quantum differentiable convex functions. The consequences derived in this paper are unification and generalization of the comparable consequences in the literature on midpoint inequalities. © 2021 Muhammad Aamir Ali et al., published by De Gruyter.National Natural Science Foundation of China, NSFC: 11301127, 11601485, 11626101, 11701176, 11971241, 61673169Funding information : The work was supported by the Natural Science Foundation of China (Grant Nos. 61673169, 11301127, 11701176, 11626101, 11601485, 11971241)
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