R. Malavika^1,*, M. L. Valarmathi²

Computer Systems Science and Engineering, Vol.42, No.1, pp. 229-243, 2022, DOI:10.32604/csse.2022.020947 - 02 December 2021

Abstract Web service applications are increasing tremendously in support of high-level businesses. There must be a need of better server load balancing mechanism for improving the performance of web services in business. Though many load balancing methods exist, there is still a need for sophisticated load balancing mechanism for not letting the clients to get frustrated. In this work, the server with minimum response time and the server having less traffic volume were selected for the aimed server to process the forthcoming requests. The Servers are probed with adaptive control of time with two thresholds L… More >

Alex Rudniy^*

CMC-Computers, Materials & Continua, Vol.71, No.1, pp. 979-992, 2022, DOI:10.32604/cmc.2022.016676 - 03 November 2021

Abstract This paper describes the process of design and construction of a data warehouse (“DW”) for an online learning platform using three prominent technologies, Microsoft SQL Server, MongoDB and Apache Hive. The three systems are evaluated for corpus construction and descriptive analytics. The case also demonstrates the value of evidence-centered design principles for data warehouse design that is sustainable enough to adapt to the demands of handling big data in a variety of contexts. Additionally, the paper addresses maintainability-performance tradeoff, storage considerations and accessibility of big data corpora. In this NSF-sponsored work, the data were processed, transformed,… More >

Buddhadeva Sahoo^1,*, Sangram Keshari Routray², Pravat Kumar Rout², Mohammed M. Alhaider³

CMC-Computers, Materials & Continua, Vol.70, No.2, pp. 2319-2346, 2022, DOI:10.32604/cmc.2022.019559 - 27 September 2021

Abstract This paper presents a combined control and modulation technique to enhance the power quality (PQ) and power reliability (PR) of a hybrid energy system (HES) through a single-phase 11-level cascaded H-bridge inverter (11-CHBI). The controller and inverter specifically regulate the HES and meet the load demand. To track optimum power, a Modified Perturb and Observe (MP&O) technique is used for HES. Ultra-capacitor (UCAP) based energy storage device and a novel current control strategy are proposed to provide additional active power support during both voltage sag and swell conditions. For an improved PQ and PR, a… More >

H. Abdelfattah¹, A. A. Abouelsoud², Fahd A. Banakhr³, Mohamed I. Mosaad^3,*

Intelligent Automation & Soft Computing, Vol.31, No.1, pp. 591-605, 2022, DOI:10.32604/iasc.2022.018765 - 03 September 2021

Abstract Induction motors are still the most used in industrial applications due to the simplicity of installation and low maintenance cost, especially for the squirrel cage type. The significant development in power electronics in terms of high-speed technologies in power electronic switches, their availability in high ratings, and the considerable decrease in the cost of the power electronics components supports this increase in uses. However, changing the induction motor's speed with loading, load torque measurement devices, and speed sensors limit this increase in using such motors. This paper proposes a state feedback controller-based backstepping technique for… More >

Xiaojuan Lu, Qingbo Zhang^*

Energy Engineering, Vol.118, No.6, pp. 1729-1740, 2021, DOI:10.32604/EE.2021.014938 - 10 September 2021

Abstract In the process of grid-connected photovoltaic power generation, there are high requirements for the quality of the power that the inverter breaks into the grid. In this work, to improve the power quality of the grid-connected inverter into the grid, and the output of the system can meet the grid-connected requirements more quickly and accurately, we exhibit an approach toward establishing a mixed logical dynamical (MLD) model where logic variables were introduced to switch dynamics of the single-phase photovoltaic inverters. Besides, based on the model, our recent efforts in studying the finite control set model More >

Sangeetha Ganesan^*, Sumathi Ganesan

Intelligent Automation & Soft Computing, Vol.30, No.2, pp. 387-401, 2021, DOI:10.32604/iasc.2021.019024 - 11 August 2021

Abstract Cloud Computing has been economically famous for sharing the resources of third-party applications. There may be an increase in the exploitation of the prevailing Cloud resources and their vulnerabilities as a result of the aggressive growth of Cloud Computing. In the Cache Side Channel Attack (CSCA), the attackers can leak sensitive information of a Virtual Machine (VM) which is co-located in a physical machine due to inadequate logical isolation. The Cloud Service Provider (CSP) has to modify either at the hardware level to isolate their VM or at the software, level to isolate their applications.… More >

Yilin Hu¹, Yan Xie², Bo Li^3,*, Yiqiang Jiang¹, Fu Bao¹

Energy Engineering, Vol.118, No.4, pp. 911-929, 2021, DOI:10.32604/EE.2021.014759 - 31 May 2021

Abstract Wind turbine employs pitch angle control to maintain captured power at its rated value when the wind speed is higher than rated value. This work adopts a perturbation observer based sliding-mode control (POSMC) strategy to realize robust variable-pitch control of permanent magnet synchronous generator (PMSG). POSMC combines system nonlinearities, parametric uncertainties, unmodelled dynamics, and time-varying external disturbances into a perturbation, which aims to estimate the perturbation via a perturbation observer without an accurate system model. Subsequently, sliding mode control (SMC) is designed to completely compensate perturbation estimation in real-time for the sake of achieving a More >

Quan Min¹, Min Deng¹, Zichen Zheng^2,*, Shu Wang², Xianyong Gui³, Haichuan Zhang²

Energy Engineering, Vol.118, No.4, pp. 853-874, 2021, DOI:10.32604/EE.2021.014515 - 31 May 2021

Abstract Combined with the characteristics of the distributed-drive electric vehicle and direct yaw moment control, a double-layer structure direct yaw moment controller is designed. The upper additional yaw moment controller is constructed based on model predictive control. Aiming at minimizing the utilization rate of tire adhesion and constrained by the working characteristics of motor system and brake system, a quadratic programming active set was designed to optimize the distribution of additional yaw moments. The road surface adhesion coefficient has a great impact on the reliability of direct yaw moment control, for which joint observer of vehicle… More >

Jin Zhang¹, Youliang Tang¹, Feng Yu^2,*

Energy Engineering, Vol.118, No.4, pp. 1083-1094, 2021, DOI:10.32604/EE.2021.014482 - 31 May 2021

Abstract In this paper, position sensorless control system of permanent magnet synchronous linear motor (PMSLM) based on sliding mode observer (SMO) with an improved phase-locked loop (PLL) is studied. Firstly, according to the mathematical model, a SMO is designed for sensorless control PMSLM drive. Thereafter, an improved PLL is proposed to tackle the imperfection of data overflow existed in the traditional PLL. The designed SMO incorporating with the improved PLL can be effectively suppress the pulsation of the estimated position and hence the chattering of the derived electrical angular velocity. At last, simulated and experimental results More >

Shun-Yuan Wang¹, Yun-Jung Hsu¹, Sung-Jung Hsiao², Wen-Tsai Sung^3,*

Computer Systems Science and Engineering, Vol.38, No.2, pp. 197-214, 2021, DOI:10.32604/csse.2021.015713 - 23 April 2021

Abstract This study proposes a Web platform, the Web of Things (WoT), whose Internet of Things (IoT) architecture is used to develop the technology behind a new standard Web platform. When a remote sensor passes data to a microcontroller for processing, the protocol is often not known. This study proposes a WoT platform that enables the use of a browser in a mobile device to control a remote hardware device. An optimized code is written using an artificial intelligence-based algorithm in a microcontroller. Digital data convergence technology is adopted to process the packets of different protocols… More >