Automatic Adjustment of the Lengths of Subband Adaptive Filters

Zhiqiang Ma,Kenji Nakayama,Akihiko Sugiyama 한국통신학회 1993 Asia-Pacific Conference on Communications Vol.2 No.2

Communication Resource Allocation Strategy of Internet of Vehicles Based on MEC

Zhiqiang Ma 한국정보처리학회 2022 Journal of information processing systems Vol.18 No.3

The business of Internet of Vehicles (IoV) is growing rapidly, and the large amount of data exchange has causedproblems of large mobile network communication delay and large energy loss. A strategy for resourceallocation of IoV communication based on mobile edge computing (MEC) is thus proposed. First, a model ofthe cloud-side collaborative cache and resource allocation system for the IoV is designed. Vehicles can offloadtasks to MEC servers or neighboring vehicles for communication. Then, the communication model and thecalculation model of IoV system are comprehensively analyzed. The optimization objective of minimizingdelay and energy consumption is constructed. Finally, the on-board computing task is coded, and theoptimization problem is transformed into a knapsack problem. The optimal resource allocation strategy isobtained through genetic algorithm. The simulation results based on the MATLAB platform show that: Theproposed strategy offloads tasks to the MEC server or neighboring vehicles, making full use of systemresources. In different situations, the energy consumption does not exceed 300 J and 180 J, with an averagedelay of 210 ms, effectively reducing system overhead and improving response speed.

Online Integrated Development Environment for MapReduce Programming

Zhiqiang Ma,Shuangtao Yang,Zhida Shi,Rui Yan 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.6

Though MapReduce programming model simplifies the development of parallel program, ordinary users have difficulties in setting up the development environment for MapReduce. The online integrated development environment for MapReduce programming can solve this problem, thus users need not build the environment themselves, only need to focus on the logical design of the parallel program. During the software construction, the problem of independent space setting and naming conflict of the file in the multi-user environment, and the problem of online compiling, execution and instant feedback message to client are solved. The software has been deployed and tested in Hadoop cluster, and can meet users’ basic requirements for the development of MapReduce.

Optimization of OFDMA-Based Cellular Cognitive Radio Networks

Ma, Yao,Kim, Dong In,Wu, Zhiqiang IEEE 2010 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.58 No.8

<P>In this paper, we study the coexistence and optimization of a multicell cognitive radio network (CRN) which is overlaid with a multicell primary radio network (PRN). We propose a PRN-willingness-based design framework for coexistence and subchannel sharing, and a Lagrange duality based technique to optimize the weighted sum rate (WSR) of secondary users (SUs) over multiple cells. First, to avoid unacceptable SU interference to primary users (PUs), the PRN determines its interference margin based on its target performance metric and channel conditions, and broadcasts this information to the CRN. Second, each CRN cell optimizes its WSR and implements intercell iterative waterfilling (IC-IWF) to control the intercell interference. To account for the interference and transmit power limits at SUs, multilevel waterfilling (M-WF) and direct-power truncation (DPT) duality schemes are developed. Third, we develop a serial dual update technique which enables low-complexity and fast-convergence of the proposed duality schemes. Numerical results demonstrate the effects of multiple parameters, such as the number of SUs per cell, subchannel occupancy probability (SOP), and outage probability of the PUs. Our results show that the proposed duality schemes provide a large performance enhancement than the channel-greedy and access-fairness based resource allocation schemes.</P>

A New Three-Phase Current Modulation Method to Suppress the Commutation Torque Ripple of Brushless DC Motor

Zhiqiang Wang,Shuai Yin,Tiehua Ma 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.5

The brushless DC motor’s commutation torque ripple is caused by inconsistency in the rate of phase current change. Thus, a method that considers armature resistance is proposed to modulate phase current. The three-phase control strategy, which involves the “open-phase conduction, off-phase pulse width modulation, and maintained non-commutation phase” technique, is applied during commutation at full-speed segments of the motor. Changes in each phase current are analyzed theoretically by establishing mathematical model based on phase current to determine the relative difference among shutdown phase, duty, and motor operating parameters. The turn-on and turn-off phase current change rates are made to be consistent to ensure less non-commutation phase current ripple, then the torque ripple is inhibited. The simulation results show that the phase commutation current and torque ripple coefficient of the proposed method are reduced from 56.9% and 55.5% to 6.8% and 6.1%, respectively. In the experiment system, the pulsation coefficient of the motor phase current is reduced from 40.0% to 16.7% at low speed and 50.0% to 18.8% at high speed. The simulation and experimental results show that the proposed control method significantly inhibits commutation current and torque in the full section.

Reliability Based Structural Topology Optimization Considering Non-stationary Stochastic Excitations

Zhiqiang Hu,Ziqi Wang,Cheng Su,Haitao Ma 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.3

This paper studies the optimum structural design considering non-stationary stochastic excitations. The topology optimization of the lateral bracing system of frame structures is conducted and the first-passage probability of a displacement response is minimized under the material volume constraint. The concept of Solid Isotropic Material with Penalization (SIMP) model is employed for describing the material distribution. An efficient optimization algorithm based on explicit time-domain method is developed. Numerical examples of frame structures subjected to non-stationary seismic excitations are investigated to demonstrate the effectiveness of the proposed approach.

Analysis and Optimization of Laying Process Parameters of Carbon Fiber Reinforced Thermoplastic Composites for Additive Manufacturing Using Robot

Zhiqiang Liu,Yinqi Li,Yi Hao,Zhihao Ma,Xianan Gu 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.25 No.3

The research object of this paper is carbon fiber reinforced thermoplastic composite CF/PEEK. Through control planning of robot motion, simulation and experiment on Paving pressure and paving speed are carried out, and on this basis analysis and optimization are carried out. In the analysis of laying pressure, the deformation of rigid press roll and flexible press roll under different pressures is analyzed by finite element simulation. According to the laying experiment, it is certain that the flexible press roll can obtain better laying quality when laying; different pressures are selected to lay the tow. The laying range of these pressures is determined as 50–250 N according to the quality of the tow. In the temperature experiment, the temperature change of the tow in different layers under different laying speeds is analyzed. Through the experiment, it is found that there is a strong correlation between the laying speed and the laying temperature. The experiment also found that under a certain laying speed, selecting the corresponding heating temperature range can obtain higher laying quality and that selecting appropriate paving process parameters, conducting paving tests, and conducting trajectory planning based on the process can effectively reduce paving defects. Finally, in order to solve the problem of path planning for thin-wall structure carbon fiber placement, a natural path algorithm based on Laplace smoothing is proposed. The algorithm obtains the grid surface through the discretization of the thin-walled surface structure, smooths the grid using the Laplace method, and uses the natural path method to obtain the trajectory. At the same time, the algorithm also considers the layout path boundary and layer design, etc. The problem is to complete the trajectory planning through the fiber path assisted generation software and compare the trajectory points with the traditional surface mesh method to verify the rationality of the trajectory algorithm.

A New Three-Phase Current Modulation Method to Suppress the Commutation Torque Ripple of Brushless DC Motor

Wang, Zhiqiang,Yin, Shuai,Ma, Tiehua The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.5

The brushless DC motor's commutation torque ripple is caused by inconsistency in the rate of phase current change. Thus, a method that considers armature resistance is proposed to modulate phase current. The three-phase control strategy, which involves the "open-phase conduction, off-phase pulse width modulation, and maintained non-commutation phase" technique, is applied during commutation at full-speed segments of the motor. Changes in each phase current are analyzed theoretically by establishing mathematical model based on phase current to determine the relative difference among shutdown phase, duty, and motor operating parameters. The turn-on and turn-off phase current change rates are made to be consistent to ensure less non-commutation phase current ripple, then the torque ripple is inhibited. The simulation results show that the phase commutation current and torque ripple coefficient of the proposed method are reduced from 56.9% and 55.5% to 6.8% and 6.1%, respectively. In the experiment system, the pulsation coefficient of the motor phase current is reduced from 40.0% to 16.7% at low speed and 50.0% to 18.8% at high speed. The simulation and experimental results show that the proposed control method significantly inhibits commutation current and torque in the full section.

Nucleomodulin BspJ as an effector promotes the colonization of Brucella abortus in the host

Zhongchen Ma,Shuifa Yu,Kejian Cheng,Yuhe Miao,Yimei Xu,Ruirui Hu,Wei Zheng,Jihai Yi,Huan Zhang,Ruirui Li,Zhiqiang Li,Yong Wang,Chuangfu Chen 대한수의학회 2022 Journal of Veterinary Science Vol.23 No.1

Background: Brucella infection induces brucellosis, a zoonotic disease. The intracellular circulation process and virulence of Brucella mainly depend on its type IV secretion system (T4SS) expressing secretory effectors. Secreted protein BspJ is a nucleomodulin of Brucella that invades the host cell nucleus. BspJ mediates host energy synthesis and apoptosis through interaction with proteins. However, the mechanism of BspJ as it affects the intracellular survival of Brucella remains to be clarified. Objectives: To verify the functions of nucleomodulin BspJ in Brucella's intracellular infection cycles. Methods: Constructed Brucella abortus BspJ gene deletion strain (B. abortus ΔBspJ) and complement strain (B. abortus pBspJ) and studied their roles in the proliferation of Brucella both in vivo and in vitro. Results: BspJ gene deletion reduced the survival and intracellular proliferation of Brucella at the replicating Brucella-containing vacuoles (rBCV) stage. Compared with the parent strain, the colonization ability of the bacteria in mice was significantly reduced, causing less inflammatory infiltration and pathological damage. We also found that the knockout of BspJ altered the secretion of cytokines (interleukin [IL]-6, IL-1β, IL-10, tumor necrosis factor-α, interferon-γ) in host cells and in mice to affect the intracellular survival of Brucella. Conclusions: BspJ is extremely important for the circulatory proliferation of Brucella in the host, and it may be involved in a previously unknown mechanism of Brucella's intracellular survival.

Evaluation Model for Economic Operation of Active Distribution Network Orienting to Energy Internet

Liye Ma,Zhiqiang Wang,Tao Zhu,Zhigang Lu 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.3

As the fossil energy exhausted and the environmental climate worsening, renewable energy became the main force to promote the transformation of the energy structure, This paper establishes the new evaluation index system of the issues and put forward the evaluation model for economic operation of distribution network under the background of energy internet based on the fuzzy comprehensive evaluation methods. Firstly, the new characteristics of energy internet are discussed from the aspect of regulation mechanism, energy hub, grid structure, demand management, social participation and consumptive balance. And the index system is established by the various new demand to the distribution network. Secondly, the index weights are selected by the analytic hierarchy process. Membership degrees and scores of evaluation are calculated by fuzzy comprehensive evaluation methods. Ultimately the evaluation levels were obtained. Finally, the validity and eff ectiveness of the method proposed were confi rmed through theory analysis and application example.