M. Farid Yahya¹, Reduan Mat Dan^2,3,*, M. Fadzlee Samsubaha¹, Zaini Rashid¹, Azma Putra^2,3,*

Sound & Vibration, Vol.57, pp. 119-131, 2023, DOI:10.32604/sv.2023.045029

Abstract A case study of excessive vibration on a motor-compressor system is presented in this paper. After barely two months of operation, the reciprocating compressor motor’s routine monitoring revealed excessive axial vibration amplitude. For this reason, the Operational Modal Analysis (OMA) was carried out in order to identify the primary cause. According to the investigation, one of the harmonic components which was 18 times the motor’s running speed matched with a resonance frequency of 112 Hz. According to OMA study, the motor was vibrating in torsional motion because the compressor’s load had stimulated the entire motor-compressor unit at this resonance frequency.… More >

Baofeng Ji^1,2,3,*, Ying Wang^1,2,3, Weixing Wang¹, Shahid Mumtaz⁴, Charalampos Tsimenidis⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.2, pp. 1885-1905, 2024, DOI:10.32604/cmes.2023.030872

Abstract The utilization of mobile edge computing (MEC) for unmanned aerial vehicle (UAV) communication presents a viable solution for achieving high reliability and low latency communication. This study explores the potential of employing intelligent reflective surfaces (IRS) and UAVs as relay nodes to efficiently offload user computing tasks to the MEC server system model. Specifically, the user node accesses the primary user spectrum, while adhering to the constraint of satisfying the primary user peak interference power. Furthermore, the UAV acquires energy without interrupting the primary user’s regular communication by employing two energy harvesting schemes, namely time switching (TS) and power splitting… More >

Junyan Liu¹, Ju Liu¹, Yan Wang¹, Shuang Liu¹, Qiao Wang¹, Yihe Du^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.1, pp. 205-218, 2024, DOI:10.32604/fdmp.2023.030645

Abstract The variation of the principal stress of formations with the working and geo-mechanical conditions can trigger wellbore instabilities and adversely affect the well completion. A finite element model, based on the theory of poro-elasticity and the Mohr-Coulomb rock damage criterion, is used here to analyze such a risk. The changes in wellbore stability before and after reservoir acidification are simulated for different pressure differences. The results indicate that the risk of wellbore instability grows with an increase in the production-pressure difference regardless of whether acidification is completed or not; the same is true for the instability area. After acidizing, the… More >

Tian Lu, Bohong Liu^*

Journal on Artificial Intelligence, Vol.5, pp. 113-129, 2023, DOI:10.32604/jai.2023.043970

Abstract To realize a better automatic train driving operation control strategy for urban rail trains, an automatic train driving method with improved DQN algorithm (classical deep reinforcement learning algorithm) is proposed as a research object. Firstly, the train control model is established by considering the train operation requirements. Secondly, the dueling network and DDQN ideas are introduced to prevent the value function overestimation problem. Finally, the priority experience playback and “restricted speed arrival time” are used to reduce the useless experience utilization. The experiments are carried out to verify the train operation strategy method by simulating the actual line conditions. From… More >

Yi-Li Huang¹, Fang-Yie Leu^1,2,*, Ruey-Kai Sheu¹, Jung-Chun Liu¹, Chi-Jan Huang^2,3

CMC-Computers, Materials & Continua, Vol.77, No.1, pp. 1143-1164, 2023, DOI:10.32604/cmc.2023.037161

Abstract Currently, data security mainly relies on password (PW) or system channel key (SK_CH) to encrypt data before they are sent, no matter whether in broadband networks, the 5th generation (5G) mobile communications, satellite communications, and so on. In these environments, a fixed password or channel key (e.g., PW/SK_CH) is often adopted to encrypt different data, resulting in security risks since this PW/SK_CH may be solved after hackers collect a huge amount of encrypted data. Actually, the most popularly used security mechanism Advanced Encryption Standard (AES) has its own problems, e.g., several rounds have been solved. On the other hand, if… More >

Cheng Hu^1,2, Weiheng Xiang^1,3,*, Ping Chen^2,3, Yi Yang^4,5, Libo Zhou³, Jiufang Jiang⁵, Shunkai Li^2,4, Yang Ming¹, Qing Li³

Journal of Renewable Materials, Vol.11, No.11, pp. 3945-3956, 2023, DOI:10.32604/jrm.2023.027544

Abstract The aim of this study is to enhance the value and utilization of red mud generated in the Bayer process by preparing composite cement mortars. The effects of two different types of Bayer red mud with varying physical and chemical characteristics on the fluidity, mechanical strength, mineral composition, and microstructure of the composite cement mortar were systematically evaluated. The results showed that the optimal addition of red mud A was 10 wt%, while it was 20 wt% for red mud B. The mechanical properties of the composite cement mortar met the standards for P·O42.5 cement. Furthermore, the composite mortar with… More >

Zihan Qi^*

Energy Engineering, Vol.120, No.11, pp. 2547-2563, 2023, DOI:10.32604/ee.2023.027045

Abstract A novel operation control method for relay protection in flexible DC distribution networks with distributed power supply is proposed to address the issue of inaccurate fault location during relay protection, leading to poor performance. The method combines a fault-tolerant fault location method based on long-term and short-term memory networks to accurately locate the fault section. Then, an operation control method for relay protection based on adaptive weight and whale optimization algorithm (WOA) is used to construct an objective function considering the shortest relay protection action time and the smallest impulse current. The adaptive weight and WOA are employed to obtain… More >

Shengyao Sun^1,2, Ying Du³, Jiajun Chen⁴, Xuan Zhang⁵, Jiwei Zhang^6,*, Yiyi Xu⁷

CMC-Computers, Materials & Continua, Vol.76, No.3, pp. 2879-2900, 2023, DOI:10.32604/cmc.2023.037483

Abstract In Multi-access Edge Computing (MEC), to deal with multiple user equipment (UE)’s task offloading problem of parallel relationships under the multi-constraints, this paper proposes a cooperation partial task offloading method (named CPMM), aiming to reduce UE's energy and computation consumption, while meeting the task completion delay as much as possible. CPMM first studies the task offloading of single-UE and then considers the task offloading of multi-UE based on single-UE task offloading. CPMM uses the critical path algorithm to divide the modules into key and non-key modules. According to some constraints of UE-self when offloading tasks, it gives priority to non-key… More >

Shiwei Su^1,2, Guangyong Hu², Xianghua Li³, Xin Li², Wei Xiong^2,*

Energy Engineering, Vol.120, No.10, pp. 2343-2368, 2023, DOI:10.32604/ee.2023.028500

Abstract As new power systems and dual carbon policies develop, virtual power plant cluster (VPPC) provides another reliable way to promote the efficient utilization of energy and solve environmental pollution problems. To solve the coordinated optimal operation and low-carbon economic operation problem in multi-virtual power plant, a multi-virtual power plant (VPP) electricity-carbon interaction optimal scheduling model considering integrated demand response (IDR) is proposed. Firstly, a multi-VPP electricity-carbon interaction framework is established. The interaction of electric energy and carbon quotas can realize energy complementarity, reduce energy waste and promote low-carbon operation. Secondly, in order to coordinate the multiple types of energy and… More > Graphic Abstract

Zhiguang Liu¹, Shilin Wang¹, Jian Zhao^1,*, Jianhong Hao², Fei Yu³

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.1, pp. 473-487, 2024, DOI:10.32604/cmes.2023.029729

Abstract A real-time adaptive roles allocation method based on reinforcement learning is proposed to improve human-robot cooperation performance for a curtain wall installation task. This method breaks the traditional idea that the robot is regarded as the follower or only adjusts the leader and the follower in cooperation. In this paper, a self-learning method is proposed which can dynamically adapt and continuously adjust the initiative weight of the robot according to the change of the task. Firstly, the physical human-robot cooperation model, including the role factor is built. Then, a reinforcement learning model that can adjust the role factor in real… More > Graphic Abstract