Cloud Computing (CC) is widely adopted in sectors like education, healthcare, and banking due to its scalability and cost-effectiveness. However, its internet-based nature exposes it to cyber threats, necessitating ad...
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This article proposes three-level (TL) buck-boost direct ac-ac converters based on switching-cell configuration with coupled magnetics. The proposed converters use only six active switches and can produce noninverting...
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This study introduces a high step-up DC-DC converter integrated with a novel, lossless snubber circuit. To achieve an elevated voltage gain, the design combines a voltage-lifting mechanism with a voltage-doubling circ...
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Dynamic network architectures that utilize communication, computing, and storage resources at the wireless edge are key to delivering emerging services in next-generation networks (e.g., AR/VR, 3D video, intelligent c...
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Dynamic network architectures that utilize communication, computing, and storage resources at the wireless edge are key to delivering emerging services in next-generation networks (e.g., AR/VR, 3D video, intelligent cars, etc). Network slicing can be significantly enhanced by including dynamically available resources throughout the fog/edge/cloud continuum and using mmWave/THz bands. However, network slicing of dynamic multi-tier computing networks remains under-explored. In this paper, we present a self-learning end-to-end network slicing mechanism (SELF-E2E-NS) that facilitates collaboration between the Infrastructure Provider (InP) and tenants to slice their subscribers' resources (i.e., radio, computing, and storage) as fog resources. To adapt to the uncertain availability of resources at the edge and minimize the risk of non-satisfying service level agreements (SLAs), our slicing mechanism has two operational modes. Operational mode 1 is for joint network slicing (JNS) in which the InP infrastructure is augmented with fog resources and jointly sliced to meet high throughput and delay tolerant requirements. Operational mode 2 is for independent network slicing (INS) in which the InP infrastructure and fog resources are sliced separately to achieve high throughput, low-latency, and high-reliability requirements. Our schemes leverage mmWave/THz, fog/edge/cloud computing, and caching to achieve new service requirements. We design a DQ-E2E-JNS algorithm that uses Deep Dueling network and a MAAC-E2E-INS algorithm based on multi-agent actor-critic, which incorporate service-aware pricing feedback and fog trading matching, respectively. These algorithms find the optimal slice request admission and collaboration policy that maximizes the long-term revenue of the InP and tenants for each mode. The simulation results show that our novel slicing mechanism can serve up to 4 times more requests and effectively exploits different spectrum bands and fog resources to improve re
This letter presents the design, analysis, and implementation of an electrically compact high-gain multilayer Vivaldi antenna. The multilayer antenna comprises gradient metasurface superstrate layers arranged on the t...
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Grid-tie voltage source converters(VSCs)can operate in three distinct modes:AC-dominant,DC-dominant,and balanced,depending on the placement of the stiff voltage *** distinct operation modes of the VSCs traditionally d...
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Grid-tie voltage source converters(VSCs)can operate in three distinct modes:AC-dominant,DC-dominant,and balanced,depending on the placement of the stiff voltage *** distinct operation modes of the VSCs traditionally demand different synchronization control techniques,leading to heterogeneous *** is challenging for the power system to accommodate and coordinate heterogeneous VSCs.A promising universal synchronization control technique for VSCs is the DC-link voltage synchronization control(DVSC)based on a lead compensator(LC).The LC DVSC stabilizes both the DC and AC voltages of a VSC while achieving synchronization with the AC *** results in a dual-port grid-forming(DGFM)characteristic for the ***,there has been very limited study on the stability and synchronization controller design of the VSCs with the LC DVSC operating in various *** bridge this gap,the paper presents a quantitative analysis on the stability and steady-state performance of the LC DVSC in all three operation modes of the DGFM *** on the analysis,the paper provides step-by-step design guidelines for the LC ***,the paper uncovers an instability issue related to the LC DVSC when the DGFM VSC operates in the balanced *** tackle the instability issue,a virtual resistance control is proposed and integrated with the LC *** results validate the analysis and demonstrate the effectiveness of the DGFM VSC with the LC DVSC designed using the proposed guidelines in all three operation ***,the paper demonstrates the feasibility of employing the DGFM VSC with the LC DVSC for all three possible operation modes,which can help overcome the challenges associated with accommodating and coordinating heterogeneous VSCs in the power system.
Green hydrogen has shown great potential to power microgrids as a primary source,whereas the resilient operation methodology under extreme events remains an open *** fill this gap,this letter establishes an operationa...
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Green hydrogen has shown great potential to power microgrids as a primary source,whereas the resilient operation methodology under extreme events remains an open *** fill this gap,this letter establishes an operational optimization strategy towards resilient hydrogen-powered *** frequency and voltage regulation characteristics of primary hydrogen sources under droop control and their electrical-chemical conversion process with nonlinear stack efficiency are accurately modeled by piecewise linear constraints.A resilience-oriented multi-time-slot stochastic optimization model is then formulated for an economic and robust operation under changing *** results show that the new formulation can leverage the primary hydrogen sources to achieve a resilience and safety-assured operation plan,supplying maximum critical loads while significantly reducing the frequency and voltage variations.
Multiple secondary users(SUs) perform collaborative spectrum sensing(CSS) in cognitive radio networks to improve the sensing performance. However,this system severely degrades with spectrum sensing data falsification(...
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Multiple secondary users(SUs) perform collaborative spectrum sensing(CSS) in cognitive radio networks to improve the sensing performance. However,this system severely degrades with spectrum sensing data falsification(SSDF) attacks from a large number of malicious secondary users, i.e., massive SSDF attacks. To mitigate such attacks, we propose a joint spectrum sensing and spectrum access framework. During spectrum sensing,each SU compares the decisions of CSS and independent spectrum sensing(IndSS), and then the reliable decisions are adopted as its final decisions. Since the transmission slot is divided into several tiny slots, at the stage of spectrum access, each SU is assigned with a specific tiny time slot. In accordance with its independent final spectrum decisions, each node separately accesses the tiny time *** results verify effectiveness of the proposed algorithm.
It is well-known that lithium plating significantly reduces the capacity of Li-ion batteries, particularly at elevated charging rates, high state of charge (SoC), and low temperatures. This study presents a simplified...
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Global navigation satellite systems (GNSS) face significant challenges in urban and sub-urban areas due to non-line-of-sight (NLOS) propagation, multipath effects, and low received power levels, resulting in highly no...
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