Investigation on the Stratigraphic Response and Plugging Effect Induced by Press-In Open Caisson in Mucky Soil

Yongzhi Wang,Mengbo Liu,Shaoming Liao,Qiong Yi,Junzuo He,Linqi Liu,Zhiqun Gong,Kaiying Li 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.5

Press-in open caisson method, which sinks into soil with the aid of mechanical pressure without excavation, is becoming an important method of construction in extremely soft foundations. However, many engineering problems are prone to occur in the construction of caissons, such as sinking and large deformation. In this study, the stratigraphic response model, such as soil migration during the press-in process of open caisson, is focused on. Through model tests of soil and caissons, the migration patterns of each part of the soil were carried out, and the mechanism underlying the stratigraphic response pattern was investigated. The three primary conclusions are as follows: 1) The bottom edge foot of caisson produces lateral extrusion on surrounding soil in the range of 10 cm (20%H) below, resulting in lateral movement of soil. 2) two kinds of plug, i.e., “wedged” and “unwedged” plugs exist, and the driven forces for the soil migration can be divided into three stages, i.e., caused by soil plug with active arch, by soil plug with passive arch and caused by soil squeezing effect. 3) there is a significant linear correlation between the soil plug changes, the horizontal movement of the deep soil body, and the displacement of the surface uplift. The soil plugging effect and squeezing effect are interacted and enhanced with each other. This study provides a new understanding of the stratigraphic response in the construction of press-in open caissons, andguides safety control of open caissons construction.

Securing MapReduce Result Integrity via Verification-based Integrity Assurance Framework

Yongzhi Wang,Jinpeng Wei,Yucong Duan 보안공학연구지원센터 2014 International Journal of Grid and Distributed Comp Vol.7 No.6

MapReduce, a large-scale data processing paradigm, is gaining popularity. However, like other distributed computing frameworks, MapReduce suffers from the integrity assurance vulnerability: malicious workers in the MapReduce cluster could tamper with its computation result and thereby render the overall computation result inaccurate. Existing solutions are effective in defeating the malicious behavior of non-collusive workers, but are less effective in detecting collusive workers. In this paper, we propose the Verification-based Integrity Assurance Framework (VIAF). By using task replication and probabilistic result verification, VIAF can detect both non-collusive and collusive workers, even if the malicious workers dominate the environment. We have implemented VIAF on Hadoop, an open source MapReduce implementation. Our theoretical analysis and experimental result show that VIAF can achieve high job accuracy while imposing moderate performance overhead.

Usability Evaluation Method of ECDIS Human-computer Interface Based on Emotional Experience

Yongzhi Hao,Pengjun Zheng,Yibing Wang,Tianming Yan,Zhihao Han 국제이네비해양경제학회 2019 International Journal of e-Navigation and Maritime Vol.13 No.1

At present, ECDIS has been widely used in ship positioning, collision avoidance and navigation, and has developed into an important part of integrated navigation and automation system. However, most ECDIS software focuses too much on system function and technical level when realizing powerful navigation AIDS, neglecting the problems that the crew are most concerned about, such as realizing the human-computer interface operation quickly and simply as well as obtaining the information of human-computer interaction effectively and accurately. In order to improve the design of Electronic Chart Display and Information system(ECDIS)human-computer interface and its usability effectively, a new method for evaluating ECDIS human-computer interface is proposed. Starting from the concept and connotation of usability, five-factor personality model is used to measure the users’ personality type in reference to the essence of usability (user’s emotional experience) and calculate the basic emotional variant of users. Then, according to the users’ emotional stimulation after finishing the given ECDIS task and combining with the system Usability scale (SUS), a tool dedicated to usability testing and five dimensions of usability evaluation proposed by Jakob Nielsen, father of usability, the emotion relationship model of usability and users is established by using partial least square method ( PLS ), and the validity of the model is verified with an aim to locate the key indicators that affect the usability of the ECDIS human-computer interface, It will be more helpful to improve the usability of ECDIS human-computer interface.

Nonsingular Finite-time Second Order Sliding Mode Attitude Control for Reentry Vehicle

Yongzhi Sheng,Jie Geng,Xiangdong Liu,Liang Wang 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.4

This paper presents nonlinear robust flight control strategies for the reentry vehicle which is nonlinear, coupling, and includes parameter uncertainties and external disturbances. Firstly, a finitetime second order sliding mode attitude control strategy is pointed out with the introduction of a nonsingular finite-time sliding mode manifold. By the proposed controller, the attitude tracking errors are mathematically proved to converge to zero within finite time and the chattering of sliding mode controller is alleviated without any deterioration of robustness and accuracy. For further alleviation of chattering, a smooth second order sliding mode attitude control strategy is then designed based on an improved nonsingular finite-time sliding mode manifold. Finally, the proposed strategies are applied to the attitude control of X-33 RLV in the reentry phase to verify the validity and robustness of the proposed strategies.

A Novel Adaptive High-order Sliding Mode Control based on Integral Sliding Mode

Liang Wang,Yongzhi Sheng,Xiangdong Liu 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.3

This paper presents an adaptive high-order sliding mode control scheme targeting for uncertain minimum phase nonlinear single-input-single-output (SISO) systems, which can be equivalently formulated as the finite-time stabilization of high-order input-output dynamics subject to the uncertainties of parameters such as a chain of integrators. The proposed controller is derived from the concept of integral sliding mode and consists of two parts, one part of which achieves the finite-time stabilization of the high-order input-output dynamics without uncertainties by solving a finite-horizon optimal control problem with a free-final-state. The other part adopts the adaptive sliding mode control technique considering the practical bounded uncertainties, by which a modified switching gain adaptation algorithm is developed so that the on-line switching gain selection can be executed and the upper bounds of the uncertainties are not requisite in advance. As a result, a high-order sliding mode is established, ensuring the sliding variables and its high-order derivatives converge to an arbitrarily small vicinity of the origin in finite time. Therefore, the proposed controller achieves fixed convergence time and further improves strong robustness against bounded uncertainties with lower chattering and the easy implementation. Simulation results are presented in detail to verify the effectiveness and feasibility of the proposed algorithm.

A Data-Driven Deep Learning Network for Massive MIMO Detection with High-order QAM

Yu, Yongzhi,Ying, Jie,Wang, Ping,Guo, Limin 한국통신학회 2023 Journal of communications and networks Vol.25 No.1

Massive multiple-input multiple-output (MIMO)can provide higher spectral efficiency and energy efficiencycompared to conventional MIMO systems. Unfortunately, asthe numbers of modulation orders and antennas increase, thecomputational complexity of conventional symbol detection algo-rithms becomes unaffordable and their performance deteriorates. However, deep learning (DL) techniques can provide flexibility,nonlinearity and computational parallelism for massive MIMOdetection to address these challenges. We propose an efficientdata-driven detection network, i.e., accelerated multiuser inter-ference cancellation network (AMIC-Net), for uplink massiveMIMO systems. Specifically, we first introduce an extrapolationfactor regarded as a learnable parameter into the multiuserinterference cancellation (MIC) algorithm for iterative sequentialdetection (ISD) detector through extrapolation technique toenhance the convergence performance. Then we unfold the aboveaccelerated iterative algorithm and adopt a sparsely connectedapproach, instead of fully connected, to obtain a relativelysimple deep neural network (DNN) structure to enhance thedetection performance through the data-driven DL approach. Furthermore, in order to accommodate communication scenarioswith higher-order modulation, a novel activation function isproposed, which is composed of multiple softsign activationfunctions with additional learnable parameters to implement amulti-segment mapping of the set of constellation points withdifferent modulations. Numerical results show that the proposedDL network can bring significant performance gain to ISDdetector with various massive antenna settings and outperformthe existing detectors with the same or lower computationalcomplexity, especially in high-order QAM modulation scenarios.

Field-Emission Property of Self-Purification SiC/SiOx Coaxial Nanowires Synthesized via Direct Microwave Irradiation Using Iron-Containing Catalyst

Qing Zhou,Yongzhi Yu,Shan Huang,Jiang Meng,Jigang Wang 대한금속·재료학회 2017 ELECTRONIC MATERIALS LETTERS Vol.13 No.4

SiC/SiOx coaxial nanowires were rapidly synthesized via directmicrowave irradiation in low vacuum atmosphere. During the preparationprocess, only graphite, silicon, silicon dioxide powders were used as rawmaterials and iron-containing substance was employed as catalyst. Comprehensive characterizations were employed to investigate themicrostructure of the products. The results showed that a great quantityof coaxial nanowires with uniform sizes and high aspect ratio had beensuccessfully achieved. The coaxial nanowires consist of a silicon oxide(SiOx) shell and a β-phase silicon carbide (β-SiC) core that exhibited inspecial tube brush like. In additional, nearly all the products wereachieved in the statement of pure SiC/SiOx coaxial nanowires withoutthe existence of metallic catalyst, indicating that the self-removal of iron(Fe) catalyst should be occurred during the synthesis process. Photoluminescence (PL) spectral analysis result indicated that suchnovel SiC/SiOx coaxial nanowires exhibited significant blue-shift. Besides, the measurement results of field-emission (FE) demonstratedthat the SiC/SiOx coaxial nanowires had ultralow turn-on field andthreshold field with values of 0.2 and 2.1 V/μm, respectively. The heterojunctionstructure formed between SiOx shell and SiC core, lots ofemission sites, as well as clear tips of the nanowires were applied toexplain the excellent FE properties.

Differential expression of heat shock protein 90, 70, 60 in chicken muscles postmortem and its relationship with meat quality

Zhang, Muhan,Wang, Daoying,Geng, Zhiming,Sun, Chong,Bian, Huan,Xu, Weimin,Zhu, Yongzhi,Li, Pengpeng Asian Australasian Association of Animal Productio 2017 Animal Bioscience Vol.30 No.1

Objective: The aim of this study was to investigate the expression of heat shock protein (HSP) 90, 70, and 60 in chicken muscles and their possible relationship with quality traits of meat. Methods: The breast muscles from one hundred broiler chickens were analyzed for drip loss and other quality parameters, and the levels of heat shock protein (HSP) 90, 70, and 60 were determined by immunoblots. Results: Based on the data, chicken breast muscles were segregated into low (drip loss${\leq}5%$), intermediate (5%<drip loss<9.5%) and high (drip loss${\geq}9.5$) drip loss groups. The expression of HSP90 and HSP60 were significantly lower in the high drip loss group compared to that in the low and intermediate drip loss group (p<0.05), while HSP70 was equivalent in abundance in all groups (p>0.05). Conclusion: Results of this study suggests that higher levels of HSP90 and HSP60 may be advantageous for maintenance of cell function and reduction of water loss, and they could act as potential indicator for better water holding capacity of meat.

Sensory, Physicochemical and Microbiological Changes in Water-cooked Salted Duck during Storage at 4℃

Li, Yanliang,Yao, Dongrui,Wang, Daoying,Xu, Weimin,Zhu, Yongzhi,Jin, Bangquan Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.7

Water-cooked salted ducks were tray-packaged and stored under refrigeration ($4{\pm}1^{\circ}C$) in order to evaluate the quality changes during storage. pH, total volatile basic nitrogen (TVB-N), sensory and microbiological analysis were determined at 0, 2, 4, 6, 8, 9 and 10 days of storage. pH value and TVB-N (mg N/100 g) varied from $6.47{\pm}0.16$ to $6.69{\pm}0.10$ and from $5.90{\pm}0.93$ to $13.42{\pm}2.46$, respectively. Sensory results indicated that ducks were unacceptable at the 10th day of storage. The predominant spoilage bacteria at the end of the shelf-life were Brochothrix thermosphacta, lactic acid bacteria (LAB) and minor components were Enterobacteriaceae, members of Micrococci, yeasts and moulds. Pseudomonads were also detected. Both total bacteria and the various spoilage ones, overall, increased from the initial sampling to the final day.

The Impact of Line Resistance on Load Sharing and An Improved Droop Control of DC Microgrid

CAO Wei,YANG Daopei,CAO Jialin,WANG Yongzhi,YAN Yuxing 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This paper proposes an effective DC voltage and power sharing droop control structure for DC microgrid based on public bus voltage feedback signal. Firstly, the impact of the line resistance on power sharing among droop controlled distributed generators is analyzed and the reason why the line resistance cannot be ignored is presented. Then, an improved droop control is proposed. The simulation test based on MATLAB/Simulink was implemented to demonstrate the proposed approach.