The cement clinker compressive strength (CCCS) at the specified age is a significant indicator of the clinker quality. However, as for the existing CCCS measurement process, the test block must undergo standard curing for a specified age (long waiting time), which is of poor timeliness. Cement production enterprises have long yearned for a new approach to quickly obtain the CCCS values. In this article, a new method for predicting the CCCS with high accuracy immediately using only process information that can be quickly detected is proposed. First, a more efficient feature selection technique is designed to screen out the key input variable group for the CCCS modeling. Then, considering that the traditional single kernel support vector regression (SVR) is difficult to have both good learning and generalization abilities at the same time, the advantages of polynomial kernel function and K-type kernel function are combined to construct hybrid kernel SVR, which serves as the model structures of the 3 days’ CCCS (R3) and 28 days’ CCCS (R28). Finally, an improved grey wolf optimizer algorithm is proposed for the global optimal estimation of CCCS model parameters to further improve the prediction accuracy of the constructed models. The effectiveness of the overall work is verified through various comparative experiments. The experimental results prove that our proposed method can quickly establish accurate estimation models. The optimized SVR can predict the CCCS at specified ages very accurately and timely, which is beneficial for the production of various types of cement in industry.

Enhancing the prediction of volatile and intermittent electric loads is one of the pivotal elements that contributes to the smooth functioning of modern power grids. However, conventional deep learning-based forecasting techniques fall short in simultaneously taking into account both the temporal dependencies of historical loads and the spatial structure between residential units, resulting in a subpar prediction performance. Furthermore, the representation of the spatial graph structure is frequently inadequate and constrained, along with the complexities inherent in Spatial-Temporal data, impeding the effective learning among different households. To alleviate those shortcomings, this article proposes a novel framework: Spatial-Temporal fusion adaptive gated graph convolution networks (STFAG-GCNs), tailored for residential short-term load forecasting (STLF). Spatial-Temporal fusion graph construction is introduced to compensate for several existing correlations where additional information are not known or unreflected in advance. Through an innovative gated adaptive fusion graph convolution (AFG-Conv) mechanism, Spatial-Temporal fusion graph convolution network (STFGCN) dynamically model the Spatial-Temporal correlations implicitly. Meanwhile, by integrating a gated temporal convolutional network (Gated TCN) and multiple STFGCNs into a unified Spatial-Temporal fusion layer, STFAG-GCN handles long sequences by stacking layers. Experimental results on real-world datasets validate the accuracy and robustness of STFAG-GCN in forecasting short-term residential loads, highlighting its advancements over state-of-the-art methods. Ablation experiments further reveal its effectiveness and superiority.

We propose an innovative approach to enhance welding operations by using a cyber-physical system (CPS) with layered architecture and enabling a robot to be effectively operated by its commanding human. This article focuses on the recognition of the commanding human's intention that should be executed by the robot. To this end, a virtual reality (VR) system based on the HTC Vive is used to create a remote virtual welding environment. Human hand movement speed data is collected and used to train a hidden Markov model (HMM) using the Baum-Welch algorithm. The Bayesian information criterion (BIC) is applied to determine the number of hidden states. The state occupancy probability distribution (the probability of each state at a given time) is estimated based on the human hand movement speed sequence using the forward algorithm. The human intention, defined as the intended movement in this article, is then estimated as the statistical expectation of the observable variables. Using the proposed human intention estimation algorithm, the intended movement recognized from the raw movement data is smoother, which is preferable in welding tasks. A 6-DoF industrial robot, UR-5 with a custom gas tungsten arc welding (GTAW) torch installed, works as the final performer of the welding jobs. The robot receives the intended movement data from the HMM and uses this to assist the human welding operators. Welding experiments have been conducted both with and without the proposed human intention recognition (IR) algorithm. The results show that the robot can help the operators complete welding tasks with better performance using the proposed IR system, supporting the effectiveness of the proposed VR robot-assisted welding system. Note to Practitioners-Welding is not only labor-intensive but also requires real-time adaption to the process, which is challenging for robots/machines but relatively straightforward for humans. Using a human commanded robot to perform welding can liberate humans from laborious operations and hazardous environments. To this end, a virtual reality (VR) system is used to create a virtual welding environment for a human to view the process remotely and for a human to pass his/her resultant adaptation to the robot through hand movements. However, hand movements do not always fully represent the intended adaptation of the commanding human, and the recognition of such human intention is fundamental in such a proposed method. This article established the mathematical framework for the recognition of the human intention and, thus, the foundation for effective assistance of robots to humans.

Multi-hop relaying is an economically efficient architecture for coverage extension and throughput enhancement in future wireless networks. OFDM, on the other hand, is a spectrally efficient physical layer modulation technique for broadband transmission. As a natural consequence of combining OFDM with multi-hop relaying, the allocation of per-hop subcarrier power and per-hop transmission time is crucial in optimizing the network performance. This paper is concerned with the end-to-end information outage in an OFDM based linear relay network. Our goal is to find an optimal power and time adaptation policy to minimize the outage probability under a long-term total power constraint. We solve the problem in two steps. First, for any given channel realization, we derive the minimum short-term power required to meet a target transmission rate. We show that it can be obtained through two nested bisection loops. To reduce computational complexity and signalling overhead, we also propose a sub-optimal algorithm. In the second step, we determine a power threshold to control the transmission on-off so that the long-term total power constraint is satisfied. Numerical examples are provided to illustrate the performance of the proposed power and time adaptation schemes with respect to other resource adaptation schemes.

With mobile WiMAX being widely deployed, providing a feasible solution for location service in mobile WiMAX is imperative and significant. In this paper, we propose a novel mobile WiMAX positioning scheme, which includes four steps: downlink preamble fast detection (DPFD), positioning algorithm selection mechanism based on the number of detected preambles, media access control (MAC) message signaling, and location calculation. In the first step, neighbor information carried by MOBNBR-ADV is introduced to decrease the neighbor BSs' preamble detection time. Meanwhile, Uplink Ranging Assistant Downlink-Time Difference of Arrival (URAD-TDoA)/uplink ranging assistant-cell ID (URA-CelllD) are proposed in selection mechanism for two/one preambles detected. Furthermore, new messages and detail message signaling for positioning are designed in MAC layer. By simulations, we show that the proposed positioning scheme can be a promising candidate for location service in mobile WiMAX systems.

This paper is concerned with the end-to-end transmission outage in an OFDM based wireless multi-hop network. The network consists of a source node, a destination node, and a set of serial relay nodes. Transmission outage occurs when the end-to-end transmission rate is less than a target rate. Our goal is to find an optimal power and time control policy to minimize the outage probability at a target end-to-end data rate under a long-term total power constraint. The problem is solved in two steps. First, for any given channel realization, we derive the minimum total power required to meet the target rate by varying the transmission power and time allocated to each hop. This is formulated as a convex optimization problem and is solved efficiently. We then compare the required minimum total power for each channel realization with a power threshold. If the threshold is exceeded, the transmission is turned off. The optimal threshold is chosen to meet the long-term total power constraint. Two suboptimal power and time control policies are also presented and compared with the optimal policy by simulation.

We study the end-to-end resource allocation in an OFDM based multi-hop network consisting of a one-dimensional chain of nodes including a source, a destination, and multiple relays. The problem is to maximize the end-to-end average transmission rate under a long-term total power constraint by adapting the transmission power on each subcarrier over each hop and the transmission time used by each hop in every time frame. The solution to the problem is derived by decomposing it into two subproblems: short-term time and power allocation given an arbitrary total power constraint for each channel realization, and total power distribution over all channel realizations. We show that the optimal solution has the following features: the power allocation on subcarriers over each hop has the water-filling structure and a higher water level is given to the hop with relatively poor channel condition; meanwhile, the fraction of transmission time allocated to each hop is adjusted to keep the instantaneous rates over all hops equal. To tradeoff between performance, computational complexity and signalling overhead, three suboptimal resource allocation algorithms are also proposed. Numerical results are illustrated under different network settings and channel environments.

This paper focuses on routing tree construction problem and its influence on the performance of utilizing centralized scheduling in IEEE 802.16 mesh networks. We apply three routing tree construction algorithms, namely, hop minimization modulation maximization (HMMM), energy/bit minimization (EbM), and interference minimization (IM) routing tree constructions with nodes spaced randomly. Furthermore, a novel multi-channel centralized scheduling algorithm with spatial reuse is proposed and its performance with the three routing tree construction algorithms is evaluated under variance of link capacity induced by co-channel interference. Simulation results show that the routing tree constructed by the EbM algorithm outperforms the two others. Therefore, EbM routing tree construction algorithm with multichannel scheduling algorithm with spatial reuse is highly efficient for IEEE 802.16 mesh networks.

In this paper we consider the topology aggregation problem in hierarchical ASON networks. Usually, the requirement of scalability and security of the network is fulfilled by domain division. The relevant information exchanged among domains will be greatly increased for large scale networks. The topology aggregation aims at reducing the amount of link state information without losing accuracy for routing calculation. We propose to apply a bidirectional shuffle-net model to topology abstraction procedure, which can significantly reduce the size of link state information. A genetic algorithm is utilized to construct the optimal mapping relationship between shuffle-net and aggregated topology for accuracy purpose. Simulation shows that the proposed scheme has good performance compared with symmetric-star approach and heuristic shuffle-net algorithm.

Mobile WiMAX is one of the most promising technologies for broadband wireless communication. The IEEE 802.16e standard for Mobile WiMAX, the enhanced version of the IEEE 802.16 standard with mobility support, defines the implementation of hard handover is mandatory. However, the long interruption of hard handover is horrible for delay and packet loss sensitive real-time applications such as IPTV, VoIP, SatTV. To solve this problem without many changes to 802.16e equipments, we propose an enhanced link-layer QoS aware handover scheme - passport handover to accelerate handover process. We also propose a connection CID assignment strategy to avoid confliction of CIDs of handing over services with that of ongoing services in the target BS. Simulation results prove that the scheme makes real-time downlink data transmission interruption so brief that users will not perceive the interruption. And it also greatly reduces uplink data transmission delay and packet loss probability.

In this paper, a new control plane recovery mechanism for optical user network interface is proposed against ingress nodal failure. Current standards of IETF and OIF only provide mechanisms to recover transit and egress nodal failure, while ingress nodal recovery hasn't been covered yet. Introducing an upstream recovery path message into nodal fault recovery, the proposed mechanism can be applied to ingress nodal recovery and thus reinforce control plane recovery. Detailed signaling flow is presented and simulation results show that the recovery time is cut down by the proposed mechanism. The proposed mechanism provides better interoperability between IETF and OIF standards.

This paper proposes a new integrated QoS architecture for IEEE 802.16 broadband wireless MAN in TDD mode. After analyzing the current strategies to provide IntServ for the Internet connection via IEEE802.16-2004 WirelessMAN, a mapping rule and a fast signaling mechanism for providing both InterServ and DiffServ are given under point to multi-point (PMP) and mesh mode. Comparison and performance analysis of traditional and proposed signaling mechanism are given. The simulation is conducted for VoIP, FTP and HTTP traffic with different QoS requirements. The results show that the proposed integrated QoS control mechanism is more fast and efficient for service setup and maintenance. What is more, bandwidth requirements of different applications can be satisfied by the proposed architecture

A fair and efficient service flow management architecture for IEEE802.16 broadband wireless access (BWA) systems is proposed for TDD mode. Compared with the traditional fixed bandwidth allocation, the proposed architecture adjusts uplink and downlink bandwidth dynamically to achieve higher throughput for unbalanced traffic. A deficit fair priority queue scheduling algorithm is deployed to serve different types of service flows in both uplink and downlink, which provides more fairness to the system. Simulation results show the proposed architecture can meet the QoS requirement in terms of bandwidth and fairness for all types of traffic.

Multiple access interference (MAI) is a bottleneck which limits the capacity of CDMA system. Differentiated MAI control is proposed for hybrid ARQ-II of CDMA networks by noticing that successive trials of transmission have increasing error-correcting capability in hybrid ARQ-II. Data packets are classified and put into corresponding queues according to different trials of transmission. The scheduling algorithm is studied and applied to realize such control. Simulation shows that differential MAI control using weighted round robin (WRR) or deficit weighted round robin (DWRR) scheduling has significant improvement by comparison to simple MAI control for hybrid ARQ-H in CDMA networks.

A new multiple access protocol that combines the characteristics of hybrid ARQ error control and turbo coding is proposed and investigated. If hybrid ARQ-II with code combining is applied, retransmissions are reduced and frame error rate is lowered when the channel experiences heavy traffic. It is an adaptive optimization of the balance between the CDMA processing gain and FEC coding gain. Simulation shows that using hybrid ARQ-II with code combing in PMCAP/CDMA can improve the delay performance in AWGN channels. Code limitation strategies can decrease the multiple access interference (MAI) level and frame error rate, which in turn improves the system performance when the background noise is very high.

Preamble minislot channel access protocol (PMCAP/CDMA) is a receiver-oriented medium access protocol. PMCAP/CDMA is applied to voice and data integration networks in a single cell. A dynamic code-set assignment strategy is proposed to separate voice/data access contention and guarantee the QoS of these traffics. A PCAR (proposed code-pool assignment rule) is proposed to decrease the collision probability of the same type of traffic. The simulation shows that the dynamic code-set assignment strategy is more adaptive to the fluctuation of voice/data traffic. By using PCAR in PMCAP/CDMA, the performance of data traffic is significantly improved while the performance of voice traffic remains good.