Search results for: Zhang Wenxin

Authors: Zilin Zhang

Abstract:

Agent-based simulation has become a popular method of exploring the behavior of all kinds of urban systems. The city clearly is viewed as such a system. Many urban evolution processes, such as the development or the transaction of a piece of land, can be modeled with a set of rules. Such modeling approaches can be used to gain insight into urban-development and land market transactions in the real world. Our work contributes to such type of research by modeling the transactions of lands in a city and its surrounding suburbs. By replicating the demand and supply needs in the land market, we are able to demonstrate the different transaction patterns in three types of residential areas - downtown, city-suburban, and further suburban areas. In addition, we are also able to compare the vital roles of different activation conditions play in generating the various transaction patterns of the land market at the macro level. We use this simulation to loosely test our hypotheses about the nature of activation regimes by the replication of the Zi traders’ model. In the end, we hope our analytical results can be useful for city planners and policymakers to develop rational city plans and policies for shaping sustainable urban development.

Keywords: simulation, agent-based modeling, housing market, city

Procedia PDF Downloads 89

Authors: Shaoying Guo, Yanyun Xu, Meng Zhang, Weiqing Huang

Abstract:

The wireless communication network is developing rapidly, thus the wireless security becomes more and more important. Specific emitter identification (SEI) is an vital part of wireless communication security as a technique to identify the unique transmitters. In this paper, a SEI method based on multiscale dispersion entropy (MDE) and refined composite multiscale dispersion entropy (RCMDE) is proposed. The algorithms of MDE and RCMDE are used to extract features for identification of five wireless devices and cross-validation support vector machine (CV-SVM) is used as the classifier. The experimental results show that the total identification accuracy is 99.3%, even at low signal-to-noise ratio(SNR) of 5dB, which proves that MDE and RCMDE can describe the communication signal series well. In addition, compared with other methods, the proposed method is effective and provides better accuracy and stability for SEI.

Keywords: cross-validation support vector machine, refined com- posite multiscale dispersion entropy, specific emitter identification, transient signal, wireless communication device

Procedia PDF Downloads 129

Authors: Chengcao Sun, Shujun Li, Cuili Yang, Yongyong Xi, Liang Wang, Feng Zhang, Dejia Li

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Hsa-miRNA-139-5p (miR-139-5p) has recently been discovered having anticancer efficacy in different organs. However, the role of miR-139-5p on lung cancer is still ambiguous. In this study, we investigated the role of miR-139-5p on development of lung cancer. Results indicated miR-139-5p was significantly down-regulated in primary tumor tissues and very low levels were found in a non-small cell lung cancer (NSCLC) cell lines. Ectopic expression of miR-139-5p in NSCLC cell lines significantly suppressed cell growth through inhibition of cyclin D1 and up-regulation of p57(Kip2). In addition, miR-139-5p induced apoptosis, as indicated by up-regulation of key apoptosis gene cleaved caspase-3, and down-regulation of anti-apoptosis gene Bcl2. Moreover, miR-139-5p inhibited cellular metastasis through inhibition of matrix metalloproteinases (MMP)-7 and MMP-9. Further, oncogene c-Met was revealed to be a putative target of miR-139-5p, which was inversely correlated with miR-139-5p expression. Taken together, our results demonstrated that miR-139-5p plays a pivotal role in lung cancer through inhibiting cell proliferation, metastasis, and promoting apoptosis by targeting oncogenic c-Met.

Keywords: hsa-miRNA-139-5p (miR-139-5p), c-Met, non-small cell lung cancer (NSCLC), proliferation, apoptosis

Procedia PDF Downloads 342

Authors: Haizhong Zhang, Yan-Gang Zhao

Abstract:

Fundamental period, mode shape, and participation factor are important basic information for the understanding of earthquake response of ground. In this study, a simple approach is presented to calculate these basic information of layered soil profiles. To develop this method, closed form equations are derived for analysis of free vibration of layered soil profiles firstly, based on equilibrium between inertia and elastic forces. Then, by further associating with the Madera procedure developed for estimation of fundamental period, a simple method that can directly determine the fundamental period, mode shape and participation factor is proposed. The proposed approach can be conveniently implemented in simple spreadsheets and easily used by practicing engineers. In addition, the accuracy of the proposed approach is investigated by analyzing first vibration mode of 67 representative layered soil profiles, it is found that results by the proposed method agree very well with accurate results.

Keywords: layered soil profile, natural vibration, fundamental period, fundamental mode shape

Procedia PDF Downloads 326

Authors: Xiangji Guo, Bo Zhang

Abstract:

In this paper, the phenomenon of vortex breakdown in a vortex tube was analyzed within the scope of unsteady character in swirl flows. A 3-D Unsteady Reynolds-averaged Navier–Stokes (URANS) closed by the Reynolds Stress Model (RSM) was adopted to simulate the large-scale vortex structure in vortex tube, and the numerical model was verified by the steady results. The swirl number was calculated for the vortex tube and the flow field was classed as strong swirl flow. According to the results, a time-dependent spiral flow field gyrates around a central recirculation zone which is precessing around the axis of the tube, and manifests the flow structure is the spiral type (S-type) vortex breakdown. The vortex breakdown is crucial for the formation of the central recirculation zone (CRZ), a further discussion was about the affection on CRZ with the different external conditions of vortex tube, the study on the unsteady characters was expected to hope to design of vortex tube and analyze the energy separation effect.

Keywords: vortex tube, vortex breakdown, central recirculation zone, unsteady, energy separation

Procedia PDF Downloads 317

Authors: Haonan Hu, Shuge Lei, Dasheng Sun, Huabin Zhang, Kehong Yuan, Jian Dai, Jijun Tang

Abstract:

This paper focuses on the classification task of breast ultrasound images and conducts research on the reliability measurement of classification results. A dual-channel evaluation framework was developed based on the proposed inference reliability and predictive reliability scores. For the inference reliability evaluation, human-aligned and doctor-agreed inference rationals based on the improved feature attribution algorithm SP-RISA are gracefully applied. Uncertainty quantification is used to evaluate the predictive reliability via the test time enhancement. The effectiveness of this reliability evaluation framework has been verified on the breast ultrasound clinical dataset YBUS, and its robustness is verified on the public dataset BUSI. The expected calibration errors on both datasets are significantly lower than traditional evaluation methods, which proves the effectiveness of the proposed reliability measurement.

Keywords: medical imaging, ultrasound imaging, XAI, uncertainty measurement, trustworthy AI

Procedia PDF Downloads 101

Authors: Yan Zhang

Abstract:

With the development of commercial movies, more and more instructors are drawn to adapt film pedagogy to teach history and culture. By challenging traditional standards of classroom culture, instruction through film represents an intersection of modernity and adaptability which is no longer optional but essential to maintaining educational accessibility. First, this presentation describes special features of the film that can be used in the classroom and help students acquire intercultural communicative competence (ICC) and achieve the learning goal. Second, the author brings forward the 5 A STAIRCASE model (Acknowledge-Adjust-Acculturate-Act-Assess) to explore how students acquire international communicative competence. Third, this article presents the intersections between new digital environments and classroom practice, such as how films can contribute to combining classical and contemporary Chinese cultures seamlessly and how film pedagogy can be an effective way to get students to engage in deeper critical thinking by exposing them to visuals, music, language, and styling which do not exist in traditional learning formats. Last, the student’s final video project will be exemplified at the end, demonstrating how to engage students in the analysis and experience of history and culture.

Keywords: intercultural education, curriculum, media, history

Procedia PDF Downloads 74

Authors: Qingyu Zhang, Mei Cao

Abstract:

As the environments become increasingly uncertain, firms have attempted to achieve greater supply chain collaboration. Supply chain collaboration can generate significant benefits to its members, e.g., reducing risks and decreasing transaction costs. However, a strong relationship is often related to firm’s culture (e.g., short-term vs. long-term interests). The objective of the study is to explore the effect of long-term oriented culture on product quality in a supply chain. Data was collected through a Web survey of U.S. manufacturing firms. Structural equation modeling (LISREL) was used to analyze the data. The results support the mediating roles of goal congruence and communication in the relationship between long-term orientation and product quality in the supply chain. Goal congruence partially mediates the relationship between long-term orientation and communication; communication completely mediates the relationship between goal congruence and product quality. Without high levels of communication, goal congruence cannot improve product quality in a positive way.

Keywords: communication, long-term orientation, product quality, supply chain

Procedia PDF Downloads 347

Authors: Yan Zeng, Li Tao, Liujun Han, Tianye Zhang, Yongan Yu, Kaijun Ma, Long Chen

Abstract:

Mechanical asphyxia is one of the main cause of death; however, death by mechanical asphyxia may be difficult to prove in court, particularly in cases in which corpses exhibit no obvious signs of asphyxia. To identify a credible biomarker of asphyxia, we first examined the expression levels of all the mRNAs in human cardiac tissue specimens subjected to mechanical asphyxia and compared these expression levels with those of the corresponding mRNAs in specimens subjected to craniocerebral injury. A total of 119 differentially expressed mRNAs were selected and the expression levels of these mRNAs were examined in 44 human cardiac tissue specimens subjected to mechanical asphyxia, craniocerebral injury, hemorrhagic shock and other causes of death. We found that DUSP1 and KCNJ2 were up-regulated in tissue specimens of mechanical asphyxia compared with control tissues, with no significant correlation between age, environmental temperature and PMI, indicating that DUSP1 and KCNJ2 may associate with mechanical asphyxia-induced death and can thus serve as useful biomarkers of death by mechanical asphyxia.

Keywords: mechanical asphyxia, biomarkers, DUSP1, KCNJ2, cardiac tissue

Procedia PDF Downloads 295

Authors: Bilal Ashraf, Qianxiao Zhang

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This study empirically investigated the linkage amid financial development and its important determinants such as information and communication technology, natural resource rents, economic growth, current account balance, and gross savings in 107 economies. This paper preferred to employ the second-generation unit root tests to handle the issues of slope heterogeneity and “cross-sectional dependence” in panel data. The “Kao, Pedroni, and Westerlund tests” confirm the long-lasting connections among the variables under study, while the significant endings of “cross-sectionally augmented autoregressive distributed lag (CS-ARDL)” exposed that NRR, CAB, and S negatively affected the financial development while ICT and EG stimulates the procedure of FD. Further, the robustness analysis's application of FGLS supports the appropriateness and applicability of CS-ARDL. Finally, the findings of “DH causality analysis” endorse the bidirectional causality linkages amongst research factors. Based on the study's outcomes, we suggest some policy suggestions that empower the process of financial development, globally.

Keywords: determinants of financial developments, CS-ARDL, financial development, global sample, causality analysis

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Authors: Gnanachandrasamy G., Zhou Y., Ramkumar T., Venkatramanan S., Wang S., Mo Liping, Jingru Zhang

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In order to assess the heavy metal contamination totally fourty five groundwater samples were collected from the coastal part of Cauvery deltaic region, South India, during monsoon season in the year of 2017. The study area lies between longitudes 79º15’ to 79º 50’ E and latitudes 10º10’ to 11º20’ N with total area of 2,569 km². The concentration of As, Ba, Cd, Cr, Co, Cu, Ni, Pb, Se, and Zn were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The heavy metals ranged between 0.007-117.8 µg/l for As, 8.503-1281 µg/l for Ba, 0.006-0.12 µg/l for Cd, 0.23-5.572µg/l for Cr, 0.44-17.9 µg/l for Co, 0.633-11.56 µg/l for Cu, 0.467-29.34 µg/l for Ni, 0.008-5.756 µg/l for Pb, 0.979 to 45.49 µg/l for Se, and 2.712-10480 µg/l for Zn in the groundwaters. A comparison of heavy metal concentration with WHO and BIS drinking water standards shows that Ni, Zn, As, Se, and Ba level is higher than the drinking water standards in some of the groundwater samples, and the concentrations of all the other heavy metals were lower than the drinking water standards. The present levels of heavy metal concentration in the studied area groundwaters are moderate to severe to public health and environmental concerns and need attention.

Keywords: cauvery delta, drinking water, groundwater, heavy metals

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Authors: Han Xiao, Ruan Qi, Zhang Lei, Qi Yan

Abstract:

Space environment simulator is a facility used to conduct thermal test for spacecraft, and vacuum vessel is the main body of it. According to the requirements for thermal tests of the spacecraft and its solar array panels, the primary vessel and the side vessels are designed to be a combinative structure connected with aperture, which ratio reaches 0.7. Since the vacuum vessel suffers 0.1MPa external pressure during the process of thermal test, in order to ensure the simulator’s reliability and safety, it’s necessary to calculate the vacuum vessel’s intensity and stability. Based on the impact of large openings to vacuum vessel structure, this paper explored the reinforce design and analytical way of vacuum vessel with large openings, using a large space environment simulator’s vacuum vessel design as an example. Tests showed that the reinforce structure is effective to fulfill the requirements of external pressure and the gravity. This ensured the reliability of the space environment simulator, providing a guarantee for developing the spacecraft.

Keywords: vacuum vessel, large opening, space environment simulator, structure design

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Authors: Yunwei Zhang, Na Li, Yuhong Niu

Abstract:

Bone tissue engineering scaffold was regarded as an important clinical technology of curing bony defect. The patent protection of bone tissue engineering scaffold had been paid more attention and strengthened all over the world. This study analyzed the future development trends of international technologies in the field of bone tissue engineering scaffold and its patent protection. This study used the methods of data classification and classification indexing to analyze 2718 patents retrieved in the patent database. Results showed that the patents coming from United States had a competitive advantage over other countiries in the field of bone tissue engineering scaffold. The number of patent applications by a single company in U.S. was a quarter of that of the world. However, the capability of R&D in China was obviously weaker than global level, patents mainly coming from universities and scientific research institutions. Moreover, it would be predicted that synthetic organic materials as new materials would be gradually replaced by composite materials. The patent technology protections of composite materials would be more strengthened in the future.

Keywords: bone tissue engineering, patent analysis, Scaffold material, patent protection

Procedia PDF Downloads 133

Authors: Golnar Behzadi, Michael O'Sullivan, Tava Olsen, Abraham Zhang

Abstract:

By definition, increasing supply chain resilience improves the supply chain’s ability to return to normal, or to an even more desirable situation, quickly and efficiently after being hit by a disruption. This is especially critical in agribusiness supply chains where the products are perishable and have a short life-cycle. In this paper, we propose a resilience metric to capture and improve the recovery process in terms of both performance and time, of an agribusiness supply chain following either supply or demand-side disruption. We build a model that determines optimal supply chain recovery planning decisions and selects the best resilient strategies that minimize the loss of profit during the recovery time window. The model is formulated as a two-stage stochastic mixed-integer linear programming problem and solved with a branch-and-cut algorithm. The results show that the optimal recovery schedule is highly dependent on the duration of the time-window allowed for recovery. In addition, the profit loss during recovery is reduced by utilizing the proposed resilient actions.

Keywords: agribusiness supply chain, recovery, resilience metric, risk management

Procedia PDF Downloads 397

Authors: Yaowei Hu, Yongkai Wu, Lu Zhang, Xintao Wu

Abstract:

Causal inference from observational data is receiving wide applications in many fields. However, unidentifiable situations, where causal effects cannot be uniquely computed from observational data, pose critical barriers to applying causal inference to complicated real applications. In this paper, we develop a bounding method for estimating the average causal effect (ACE) under unidentifiable situations due to hidden confounders. We propose to parameterize the unknown exogenous random variables and structural equations of a causal model using neural networks and implicit generative models. Then, with an adversarial learning framework, we search the parameter space to explicitly traverse causal models that agree with the given observational distribution and find those that minimize or maximize the ACE to obtain its lower and upper bounds. The proposed method does not make any assumption about the data generating process and the type of the variables. Experiments using both synthetic and real-world datasets show the effectiveness of the method.

Keywords: average causal effect, hidden confounding, bound estimation, generative adversarial learning

Procedia PDF Downloads 191

Authors: Li Minghui, Min Shaorong, Zhang Jun

Abstract:

This paper aims for studying the operational efficiency of surface warship’s motorized evasion to acoustic homing torpedo. It orderly developed trajectory model, self-guide detection model, vessel evasion model, as well as anti-torpedo error model in three-dimensional space to make up for the deficiency of precious researches analyzing two-dimensionally confrontational models. Then, making use of the Monte Carlo method, it carried out the simulation for the confrontation process of evasion in the environment of MATLAB. At last, it quantitatively analyzed the main factors which determine vessel’s survival probability. The results show that evasion relative bearing and speed will affect vessel’s survival probability significantly. Thus, choosing appropriate evasion relative bearing and speed according to alarming range and alarming relative bearing for torpedo, improving alarming range and positioning accuracy and reducing the response time against torpedo will improve the vessel’s survival probability significantly.

Keywords: acoustic homing torpedo, vessel evasion, monte carlo method, torpedo defense, vessel's survival probability

Procedia PDF Downloads 455

Authors: Li Feng, Cheng Zhang, Chuanzhou Yuang

Abstract:

Understanding the macromolecular structure of low-rank coal is very important for its gasification and liquefaction. The pyrolysis is one of the methods of analyzing the macromolecular structure of coal. The gaseous products decomposed directly by the raw lignite at 500 °C and indirectly by tar products from raw lignite pyrolysis at 500 °C were investigated and compared by thermogravimetry, gas chromatography and mass spectrum coupled instrument system (TG/GC/MS) in this paper. The results show that 52 kinds of products were found from the raw lignite and 70 kinds of products from the tar. The pyrolysis products directly from the lignite appear more monocyclic aromatic hydrocarbons and less substituent groups or branch chain, compared with the products from the tar. There is less linear chain and double bonds structure in the tar, which can be speculated that linear chain and double bonds structure took part in the generation of condensed rings and other reactions. There are more kinds of phenol and furan in the tar, which indicate that these products may be generated from the secondary reaction. The formation process of phenol, phenol naphthalene, naphthene and furan are discussed.

Keywords: composition and structure, lignite, pyrolysis of coal, tar, TG/GC/MS

Procedia PDF Downloads 141

Authors: Tiedan Huang, Chun Zhang, Caitlin Coe

Abstract:

This study investigated the quality of instructional support for young Emergent Multilingual Learners (EMLs) in 50 Universal Prekindergarten (UPK) classroom in New York City (NYC). This is one of the first empirical studies examining the instructional support for this student population. We collected data using a mixed method of structured observations of teacher-child interactions in 50 classrooms, and surveys and interviews with program leaders and the teaching teams. We found that NYC’s UPK classrooms offered warm and supportive environments for EMLs. Nevertheless, in general, instructional support was relatively low. This study identified large mindset, knowledge, and practice gaps—and a real opportunity—among NYC early childhood professionals, specifically in the areas of providing adequate instructional and linguistic support for EMLs as well as partnering with families in capturing their cultural and home literacy assets. Consistent, rigorous, and meaningful use of data is necessary to support both EMLs’ language and literacy development and teachers’/leaders’ professional development.

Keywords: high quality instruction, culturally and linguistically responsive practices, professional development, workforce development

Procedia PDF Downloads 80

Authors: Zhou Xiaowen China, Zhang Sanming China

Abstract:

Neighbourhood space as a very important part of city spaces, is an organic combination of material environment and spiritual achievement in people’ daily life, and has a real impact upon the sustainable development of the whole city. Looking back on the past 2014 World Architecture Festival (WAF), 4 out of 35winning buildings were neighbourhood designs, and all of them mentioned about space-sharing and sustainable development. In this paper, three award-winning cases were studied, including the world building of the year—the chapel (Vietnam, A21 studio), The Carve (Norway, A-Lab) and House for Trees (Vietnam, Vo Trong Nghia Architects). Urban context, planning, space construction and sustainable technology were discussed. Based on those, it was discovered that passive energy-saving technologies have been paid more and more attention, sharing space has been designed ingeniously, and the architectural forms of them reflect social inclusion and equity. This paper is aimed at summarizing the excellent works on the Festival and providing reference for the future design.

Keywords: neighbourhood design, 2014 World Architecture Festival (WAF), sustainable development, space-sharing

Procedia PDF Downloads 444

Authors: Hui Wang, Huan Zhang

Abstract:

This study uses systematic review and qualitative comparative analysis methods to comprehensively inquire about the recent street-level policy entrepreneurship research, to identify the characteristics and lessons we can learn from 20 years of street-level policy entrepreneurship literature, and the relations between political contexts and street-level policy entrepreneurs’ strategies. Using data from a systematic review of street-level policy entrepreneurship literature, we identify the sub-components of different political contexts and core strategies of street-level policy entrepreneurs and estimate the configurational relations between different political settings and street-level policy entrepreneurs’ strategies. Our results show that street-level policy entrepreneurs display social acuity, define the problem, and build team strategies when policy or political streams dominate. Street-level policy entrepreneurs will use lead-by-example strategies when both policy and political streams dominate. Furthermore, street-level policy entrepreneurs will use bureaucratic strategies, even if no stream dominates in the political context.

Keywords: policy entrepreneurs, qualitative comparative analysis, street-level bureaucracy, systematic review

Procedia PDF Downloads 111

Authors: Qiang Zhang, Xiaojian Hu1

Abstract:

Intersection is the place where vehicles and pedestrians must pass through, turn and evacuate. Obtaining the motion data of vehicles near the intersection is of great significance for transportation research. Since there are usually many targets and there are more conflicts between targets, this makes it difficult to obtain vehicle motion parameters in traffic videos of intersections. According to the characteristics of traffic videos, this paper applies video technology to realize the automated track, count and trajectory extraction of vehicles to collect traffic data by roadside surveillance cameras installed near the intersections. Based on the video recognition method, the vehicles in each lane near the intersection are tracked with extracting trajectory and counted respectively in various degrees of occlusion and visibility. The performances are compared with current recognized CPU-based algorithms of real-time tracking-by-detection. The speed of the presented system is higher than the others and the system has a better real-time performance. The accuracy of direction has reached about 94.99% on average, and the accuracy of classification and statistics has reached about 75.12% on average.

Keywords: tracking and statistics, vehicle, signalized intersection, motion parameter, trajectory

Procedia PDF Downloads 221

Authors: Rui Chen, Jinfeng Zhang, Chun-Sing Lee

Abstract:

In the past couple of decades, nanoscale metal-organic frameworks (NMOFs) have been highlighted as promising delivery platforms for biomedical applications, which combine many potent features such as high loading capacity, progressive biodegradability and low cytotoxicity. While NMOF has been extensively used as carriers for drugs of different modalities, so far there is no report on exploiting the advantages of NMOF for combination therapy. Herein, we prepared core-shell nanoparticles, where each nanoparticle contains a single graphitic-phase carbon nitride (g-C3N4) nanosheet encapsulated by a zeolitic-imidazolate frameworks-8 (ZIF-8) shell. The g-C3N4 nanosheets are effective visible-light photosensitizer for photodynamic therapy (PDT). When hosting DOX (doxorubicin), the as-synthesized core-shell nanoparticles could realize combinational photo-chemo therapy and provide dual-color fluorescence imaging. Therefore, we expect NMOFs-based core-shell nanoparticles could provide a new way to achieve much-enhanced cancer therapy.

Keywords: carbon nitride, combination therapy, drug delivery, nanoscale metal-organic frameworks

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Authors: Qiang Zhang, Xiaojian Hu

Abstract:

Aiming at the problem of the existing real-time evaluation methods for traffic safety status, a video information-based urban road section traffic safety status evaluation method was established, and the rapid detection method of traffic flow parameters based on video information is analyzed. The concept of the speed dispersion of the road section that affects the traffic safety state of the urban road section is proposed, and the method of evaluating the traffic safety state of the urban road section based on the speed dispersion of the road section is established. Experiments show that the proposed method can reasonably evaluate the safety status of urban roads in real-time, and the evaluation results can provide a corresponding basis for the traffic management department to formulate an effective urban road section traffic safety improvement plan.

Keywords: intelligent transportation system, road traffic safety, video information, vehicle speed dispersion

Procedia PDF Downloads 164

Authors: Luyao Zhang, Tianyu Wu, Jiayi Li, Carlos-Gustavo Salas-Flores, Saad Lahrichi

Abstract:

Recent advances in AI have made algorithmic trading a central role in finance. However, current research and applications are disconnected information islands. We propose a generally applicable pipeline for designing, programming, and evaluating algorithmic trading of stock and crypto tokens. Moreover, we provide comparative case studies for four conventional algorithms, including moving average crossover, volume-weighted average price, sentiment analysis, and statistical arbitrage. Our study offers a systematic way to program and compare different trading strategies. Moreover, we implement our algorithms by object-oriented programming in Python3, which serves as open-source software for future academic research and applications.

Keywords: algorithmic trading, AI for finance, fintech, machine learning, moving average crossover, volume weighted average price, sentiment analysis, statistical arbitrage, pair trading, object-oriented programming, python3

Procedia PDF Downloads 144

Authors: Yi Ming Zhang, Zhan Xi Wang, Hang Chen, Gang Wang

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Manual polishing has problems such as high labor intensity, low production efficiency and difficulty in guaranteeing the consistency of polishing quality. It is more and more necessary to replace manual polishing with robot polishing. Polishing force directly affects the quality of polishing, so accurate tracking and control of polishing force is one of the most important conditions for improving the accuracy of robot polishing. The traditional force control strategy is difficult to adapt to the strong coupling of force control and position control during the robot polishing process. Therefore, based on the analysis of force-based impedance control and position-based impedance control, this paper proposed a new type of adaptive controller. Based on force feedback control of active compliance control, the controller can adaptively estimate the stiffness and position of the external environment and eliminate the steady-state force error produced by traditional impedance control. The simulation results of the model shows that the adaptive controller has good adaptability to changing environmental positions and environmental stiffness, and can accurately track and control polishing force.

Keywords: robot polishing, force feedback, impedance control, adaptive control

Procedia PDF Downloads 199

Authors: Yang Jian-Hong, Zhang Ren-Cheng, Huang Li

Abstract:

Arc fault is one of the main inducements of electric fires. Arc Fault Detection Device (AFDD) can detect arc fault effectively. Arc fault detections and unhooking standards are the keys to AFDD practical application. First, an arc fault continuous production system was developed, which could count the arc half wave number. Then, Combining with the UL1699 standard, ignition probability curve of cotton and unhooking time of various currents intensity were obtained by experiments. The combustion degree of arc fault could be expressed effectively by arc area. Experiments proved that electric fires would be misjudged or missed only using arc half wave number as AFDD unhooking basis. At last, Practical tests were carried out on the self-developed AFDD system. The result showed that actual AFDD unhooking time was the sum of arc half wave cycling number, Arc wave identification time and unhooking mechanical operation time And the first two shared shorter time. Unhooking time standard depended on the shortest mechanical operation time.

Keywords: arc fault detection device, arc area, arc half wave, unhooking time, arc fault

Procedia PDF Downloads 507

Authors: Zhang Bian, Zhao Jijun

Abstract:

The urban layout of Xi’an city (the capital Chang’an in the Tang dynasty) was shaped by feudal etiquette, but this dominant factor was replaced by modern city planning during the period of the Republic of China. This makes Xi’an a representative case to explore the transformation process of Chinese cities in the early 20^th century. By analyzing the contrast and connection between the historical texts of city planning and the realistic construction activities recorded by the maps and images, this paper reviews the transformation process of the urban space of Xi’an in the early 20^th century and divides it into four phases according to important events that significantly impacted planning and construction activities. Based on this, the entire transformation of Xi’an’s city planning and practices can be characterized by three aspects: 1) the dominant force of the city plan and construction changed with the establishment of modern city administrations; 2) the layout of the city was continuously broadened to meet the demand of modern economy and city life; and, 3) the ritual space was transformed into practical space for commercial and recreational activities.

Keywords: city space, the early 20th century, transformation, Xi’an city

Procedia PDF Downloads 164

Authors: Mohsen Torabi, Kaili Zhang

Abstract:

This work considers forced convection in a channel partially filled with porous media from local thermal non-equilibrium (LTNE) point of view. The channel is heated with constant heat flux from the lower side and is isolated on the top side. The wall heat flux is considered to be divided between the solid and fluid phases based on their temperature gradients and effective thermal conductivities. The general forms of the velocity and temperature fields are analytically obtained. To obtain the constant parameters for temperature equations, a numerical solution is considered. Using different thermophysical parameters, both velocity and temperature fields are comprehensively illustrated. Discussions regarding bifurcation phenomenon are provided. Since this geometry has not been considered yet, the present analysis is a useful addition to the literature on thermal performance of porous systems from LTNE perspective.

Keywords: local thermal non-equilibrium, forced convection, thermal bifurcation, porous-fluid interface, combined analytical-numerical solution

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Authors: Yuxin Wu, Yu-Shing Wang, Zitao Zhang

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A high-speed and time-lapse S-wave velocity measurement system has been built up for S-wave tomography in sand. This system is based on bender elements and applied to model pile tests in a tailor-made pressurized chamber to monitor the shear wave velocity distribution during pile installation in sand. Tactile pressure sensors are used parallel together with bender elements to monitor the stress changes during the tests. Strain gages are used to monitor the shaft resistance and toe resistance of pile. Since the shear wave velocity (Vs) is determined by the shear modulus of sand and the shaft resistance of pile is also influenced by the shear modulus of sand around the pile, the purposes of this study are to time-lapse monitor the S-wave velocity distribution change at a certain horizontal section during pile installation and to correlate the S-wave velocity distribution and shaft resistance of pile in sand.

Keywords: bender element, pile, shaft resistance, shear wave velocity, tomography

Procedia PDF Downloads 429

Authors: Sibo Lu, Zhongkai Qian, Haotian Zhang

Abstract:

This article examines the phenomenon of micro-sovereignty in the context of property management and its implications for biopolitics and urban governance in mainland China. It explores the transformation of urban spaces into privatized communities managed by property companies, leading to the reterritorialization of urban areas and the segmentation of urban populations. Drawing on legal frameworks, we analyze how commercial real estate development and property management have reshaped the urban landscape, placing nearly all urban residents within service areas of property management firms, thus establishing micro-sovereign entities that exercise control over residential spaces. Through a critique of property management's sovereign effects on social organization and the exploration of autonomous, democratic alternatives in community governance, this article contributes to the broader discourse on sovereignty, governance, and resistance within the urban milieu of contemporary China. It underscores the urgent need for more democratic forms of community management that can transcend the capitalist logic of property management companies and foster genuine participatory governance at the grassroots level.

Keywords: biopolitic, critical theory, political sociology, political philosophy

Procedia PDF Downloads 47