Mohd Asyraf Zulkifley^1,*, Ali Fayyaz Munir², Mohd Edil Abd Sukor³, Muhammad Hakimi Mohd Shafiai⁴

CMC-Computers, Materials & Continua, Vol.75, No.2, pp. 4395-4418, 2023, DOI:10.32604/cmc.2023.036094

Abstract A well-managed financial market of stocks, commodities, derivatives, and bonds is crucial to a country’s economic growth. It provides confidence to investors, which encourages the inflow of cash to ensure good market liquidity. However, there will always be a group of traders that aims to manipulate market pricing to negatively influence stock values in their favor. These illegal trading activities are surely prohibited according to the rules and regulations of every country’s stock market. It is the role of regulators to detect and prevent any manipulation cases in order to provide a trading platform that is fair and efficient. However,… More >

Saeed Kazemi Najafi¹, Farhood Najafi², Antonio Pizzi^3,*, Fatemeh Hassani Khorshidi^1,*, Rabi Behrooz¹

Journal of Renewable Materials, Vol.11, No.5, pp. 2171-2189, 2023, DOI:10.32604/jrm.2023.027835

Abstract Polyols are groups of organic compounds which contain carbon and are randomly linked to other atoms, especially carbon-carbon and carbon-hydrogen. These compounds are mainly used as reactants to make other polymers. Among biopolymers, lignin is regarded as the base of a new polymer in polyol construction. The present study aimed to investigate the effects of amine type (diethylenetriamine and ethylenediamine) on the modification of lignin-based polyols, so as to provide an alternative to petroleum polyols and, in turn, increase functional groups and reduce their harm to humans’ health and the environment. To this aim, first, lignin was extracted from raw… More > Graphic Abstract

Jun Lee¹, Hyun Kwon^2,*

CMC-Computers, Materials & Continua, Vol.75, No.1, pp. 2025-2042, 2023, DOI:10.32604/cmc.2023.036051

Abstract A concurrency control mechanism for collaborative work is a key element in a mixed reality environment. However, conventional locking mechanisms restrict potential tasks or the support of non-owners, thus increasing the working time because of waiting to avoid conflicts. Herein, we propose an adaptive concurrency control approach that can reduce conflicts and work time. We classify shared object manipulation in mixed reality into detailed goals and tasks. Then, we model the relationships among goal, task, and ownership. As the collaborative work progresses, the proposed system adapts the different concurrency control mechanisms of shared object manipulation according to the modeling of… More >

Van-Truong Nguyen^*

CMC-Computers, Materials & Continua, Vol.74, No.2, pp. 2771-2787, 2023, DOI:10.32604/cmc.2023.033460

Abstract In this paper, a non-negative adaptive mechanism based on an adaptive nonsingular fast terminal sliding mode control strategy is proposed to have finite time and high-speed trajectory tracking for parallel manipulators with the existence of unknown bounded complex uncertainties and external disturbances. The proposed approach is a hybrid scheme of the online non-negative adaptive mechanism, tracking differentiator, and nonsingular fast terminal sliding mode control (NFTSMC). Based on the online non-negative adaptive mechanism, the proposed control can remove the assumption that the uncertainties and disturbances must be bounded for the NFTSMC controllers. The proposed controller has several advantages such as simple… More >

Li Ding, Yong Yao^*, Rui Ma

CMES-Computer Modeling in Engineering & Sciences, Vol.135, No.2, pp. 1539-1558, 2023, DOI:10.32604/cmes.2022.023003

Abstract With the increasing demand for interactive aerial operations, the application of aerial manipulators is becoming more promising. However, there are a few critical problems on how to improve the energetic efficiency and pose control of the aerial manipulator for practical application. In this paper, a novel cable-driven aerial manipulator used for remote water sampling is proposed and then its rigid-flexible coupling dynamics model is constructed which takes joint flexibility into account. To achieve high precision joint position tracking under lumped disturbances, a newly controller, which consists of three parts: linear extended state observer, adaptive super-twisting strategy, and fractional-order nonsingular terminal… More >

Li Ding^1,*, Rui Ma¹, Zhengtian Wu², Rongzhi Qi¹, Wenrui Ruan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.135, No.1, pp. 441-464, 2023, DOI:10.32604/cmes.2022.022642

Abstract This article proposes a novel method for maintaining the trajectory of an aerial manipulator by utilizing a fast nonsingular terminal sliding mode (FNTSM) manifold and a linear extended state observer (LESO). The developed control method applies an FNTSM to ensure the tracking performance’s control accuracy, and an LESO to estimate the system’s unmodeled dynamics and external disturbances. Additionally, an improved salp swarm algorithm (ISSA) is employed to parameter tune the suggested controller by integrating the salp swarm technique with a cloud model. This approach also uses a model-free scheme to reduce the complexity of controller design without relying on complex… More >

D. Maincer^1,*, Y. Benmahamed², M. Mansour¹, Mosleh Alharthi³, Sherif S. M. Ghonein³

Intelligent Automation & Soft Computing, Vol.35, No.2, pp. 1957-1969, 2023, DOI:10.32604/iasc.2023.029210

Abstract In this paper, Support Vector Machine (SVM) and K-Nearest Neighbor (KNN) based methods are to be applied on fault diagnosis in a robot manipulator. A comparative study between the two classifiers in terms of successfully detecting and isolating the seven classes of sensor faults is considered in this work. For both classifiers, the torque, the position and the speed of the manipulator have been employed as the input vector. However, it is to mention that a large database is needed and used for the training and testing phases. The SVM method used in this paper is based on the Gaussian… More >

Elham Azadeh¹, Xinyi Chen², Antonio Pizzi^2,*, Christine Gérardin¹, Philip Gérardin¹, Hisham Essawy³

Journal of Renewable Materials, Vol.10, No.12, pp. 3217-3227, 2022, DOI:10.32604/jrm.2022.022740

Abstract Non-isocyanate polyurethane (NIPU) foams using a hydrolysable tannin, also vulgarly called tannic acid, namely here commercial chestnut wood tannin extract was prepared. Compression strength did not appear to depend on the foam apparent density while the formulation composition of the NIPU foams has been shown to be more determinant. These NIPU foams appeared to be self-extinguishing once the high temperature flame is removed. The ignition time gave encouraging results but for improved fire resistance the foams may need some fire-retardant addition. FTIR spectrometry showed the formation of non-isocyanate urethane linkages. Thermogravimetric analysis indicated a good thermal resistance of these foams,… More >

Anitha Govindhan^1,*, Karnam Anantha Sunitha², Sivanathan Kandhasamy³

Intelligent Automation & Soft Computing, Vol.35, No.1, pp. 351-365, 2023, DOI:10.32604/iasc.2023.026361

Abstract This paper presents a Model-Based Design (MBD) approach for the design and control of a customized manipulator intended for drilling and positioning of dental implants accurately with minimal human intervention. While performing an intra-oral surgery for a prolonged duration within a limited oral cavity, the tremor of dentist's hand is inevitable. As a result, wielding the drilling tool and inserting the dental implants safely in accurate position and orientation is highly challenging even for experienced dentists. Therefore, we introduce a customized manipulator that is designed ergonomically by taking in to account the dental chair specifications and anthropomorphic data such that… More >

Lei Zhang^1,2,*, Shouzhi Huang^1,2, Zhaocai Du³, Guangyao Ouyang^1,2, Heping Chen⁴

CMC-Computers, Materials & Continua, Vol.72, No.3, pp. 4817-4832, 2022, DOI:10.32604/cmc.2022.026845

Abstract In this study, a hyper-redundant manipulator was designed for detection and searching in narrow spaces for aerospace and earthquake rescue applications. A forward kinematics equation for the hyper-redundant manipulator was derived using the homogeneous coordinate transformation method. Based on the modal function backbone curve method and the known path, an improved modal method for the backbone curves was proposed. First, the configuration of the backbone curve for the hyper-redundant manipulator was divided into two parts: a mode function curve segment of the mode function and a known path segment. By changing the discrete points along the known path, the backbone… More >