Volume 43,Issue 9,2020 Table of Contents

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  • 1  Experimental study on partial load characteristics of variable primary flow air-conditioning system
    QIN Han LI Nan DENG Kai TAO Chenyang
    2020, 43(9):1-8. DOI: 10.11835/j.issn.1000-582X.2020.09.001
    [Abstract](736) [HTML](809) [PDF 795.85 K](873)
    Abstract:
    An experiment table of variable flow air conditioning system was set up for studying the operation characteristics of variable primary flow air-conditioning system under partial load conditions with constant differential pressure control strategy. The results show that as the load rate decreases, the COP of the chiller increases first and then decreases, and the highest COP appears at 60% load rate. The integrated efficiency of the pump is always reduced, while the chiller input power and pump input power show different trends-the pump input power is always reduced, and the chiller input power decreases first and then increases, resulting in the total input power of chiller and pump at 27.2% load rate being higher than that at 45.1% load rate. The variable frequency operation of the pump does not satisfy the affinity law. The equation of correlations between pump input power and flow rate is obtained, reasoning out that pump input power is related to the ratio of the constant differential pressure, the resistance of the equipment room and the integrated efficiency of the pump.The input power of the pump in this experiment is approximately proportional to the second power of the flow rate.
    2  Computation accuracy analysis of indoor lighting simulation software based on BIM technology
    WU Yuting YU Juan WANG Aiying WANG Lixiong Yin Yujun
    2020, 43(9):9-23. DOI: 10.11835/j.issn.1000-582X.2020.09.002
    [Abstract](786) [HTML](715) [PDF 11.91 M](804)
    Abstract:
    The integration of lighting profession and building information modelling (BIM) technology on the same platform is still in its infancy. DIALux evo 8.2 and ElumTools 2019.07 are currently the only indoor lighting simulation software that participate in BIM technology. The calculation accuracy of them were verified using the cases 5.2 to 5.8 in CIE171:2006-test cases to assess the accuracy of lighting computer programs which published by CIE (Commission Internationale de i'Eclairage). Then the advantages and disadvantages of them were analysed. The results show that 1) both of them have high accuracy in calculating the direct illuminance of point light source and area light source, and luminous flux conservation performance; 2) the accuracy of DIALux evo 8.2 is better than ElumTools 2019.07 when calculating the indirect illuminance of large-area diffuse reflection, occlusion and different reflectivity; 3) ElumTools 2019.07 has higher accuracy when calculating small-area diffuse reflection; 4) both of them have relatively low accuracy when calculating directional transmission performance. Based on the case study, it is further concluded that the core algorithm is the main cause of errors, and both of them have defects in information exchanges. The use of photon mapping algorithms to create a full information exchange interface between buildings and lighting will be the future direction of indoor lighting simulation software development based on BIM technology.
    3  Real-time monitoring system of carbon emission in construction site under the cyber-physical systems
    LIU Guiwen YANG Hao FU Yan MAO Chao XU Pengpeng HONG Jingke LI Kaijian
    2020, 43(9):24-31. DOI: 10.11835/j.issn.1000-582X.2020.09.003
    [Abstract](1186) [HTML](1365) [PDF 1019.81 K](941)
    Abstract:
    The control of carbon emission in construction industry becomes an important research topic with the aggravation of global warming, hence the need for research of calculation and monitoring of carbon emission in construction sites. In this paper, the existing carbon emission calculation methods were combed out, and the characteristics of them were summarized. Then, the framework of real-time monitoring system of carbon emission in construction sites combined with cyber-physical systems (CPS) technology was proposed. The calculation boundary and calculation logic of carbon emission were definded, and the real-time carbon emission monitoring system was developed from hardware system and software system. Through the effective coupling of wireless sensors, servers, databases and clients, the system finally accomplished real-time monitoring and data analysis of carbon emissions in construction sites.
    4  Experiments on the performance of bond anchorage between high strength variable rib reinforcement and concrete
    WANG Yihong ZHAO Xiaoqin YAO Shengfa LIU Xi
    2020, 43(9):32-40. DOI: 10.11835/j.issn.1000-582X.2020.09.004
    [Abstract](517) [HTML](539) [PDF 6.46 M](932)
    Abstract:
    To study the influence of the increase of cross rib spacing on the bond-slip behavior between 630 MPa high-strength steel bars and concrete, a test was carried out on the bond-slip behavior between steel bars and concrete by the beam bond test method, with using 42 standard shape steel bars and reinforcement with increased cross rib spacing. The influences of the thickness of concrete cover, diameter of rebars and anchorage length on the bond and anchorage performance of two types of rebars and concrete were analyzed.The results show that the bond strength between 630 MPa high-strength steel bar and concrete with increased cross rib spacing is not lower than that of standard shape high-strength steel bars, and the change of bond strength of two types of steel bars and concrete is basically consistent with that of concrete strength, steel bar diameter and anchorage length. The increase of the distance between transverse ribs has no significant effect on the bond-slip behavior of 630 MPa steel bar and concrete.
    5  Sentence similarity computation based on syntactic dependency convolutional neural network
    XUAN Jing WU Qiong WEI Congyue WU Xing
    2020, 43(9):41-53. DOI: 10.11835/j.issn.1000-582X.2020.09.005
    [Abstract](758) [HTML](399) [PDF 2.73 M](756)
    Abstract:
    Sentence similarity computation is a basic task of many natural language processing, and its accuracy has a direct impact on the performance of language related systems, especially in machine translation, plagiarism detection, query ranking and question answering. Compared with the traditional methods that rely on shallow features like morphology, word sequence and grammar structure for sentence similarity computation, deep learning methods can integrate the deep semantic features and achieve better results. However, deep learning methods using convolutional neural networks needs to overcome defects such as narrow receptive field and insufficient long-distance information dependence when extracting text features. In this paper, a DCNN(dependency convolutional neural network) model was established to carry out dependency-based syntactic analysis for information retrieval over longer distance. We made text parsing, employing Stanford NLP for syntactic analysis, and then retrieved mutual relationship between two words in a binary combination or triplet. As lexical supplement information embedded in these word combinations, the dependency information, in addition to that of the original sentence, was added up as Convolutional Neural Network input, thus constructing a Dependency CNN. Experiment results reveal that the long distance dependency information effectively improve the similarity computation performance in our proposed dependency model on MSRP(Microsoft research paraphrase corpus) dataset, and the accuracy and F1 value are 80.33% and 85.91 respectively. The Pearson correlation coefficient of the model reaches 87.5 on SICK(Sentences invloving compositional knowledge) dataset and 92.2 on MSRvid(Microsoft videl paraphrase corpus) dataset.
    6  An android malware detection method based on system behavior sequences
    YANG Jiyun CHEN Gang YAN Ran LYU Jianbin
    2020, 43(9):54-63. DOI: 10.11835/j.issn.1000-582X.2020.09.006
    [Abstract](389) [HTML](842) [PDF 701.61 K](708)
    Abstract:
    At present, behavior features of machine learning based Android malicious code detecting approaches are independent from each other, whereas the sequential relationships between behavior features could indicate malicious behavior. In order to furtherly improve the detection accuracy, an Android malicious code detection method based on the features of system behavior sequence was proposed. Firstly, the sequences of system activities including sensitive API calls, file access, data transmission, etc. were extracted. Next, based on Markov chain model the system behavior sequences were transformed into state transition sequence, and state transition probability matrix were created. Then, the state transition probability matrix and the state occurrence frequency were used as feature sets to train the SAEs model. Finally, we examined the performance of the trained SAEs model on a dataset. The experimental results show that the proposed method performed better than the typical malicious code detection method on accuracy, precision and recall.
    7  An accurate orientation technique by removing MEMS gyroscope's noises in real time
    HE Haochen ZHANG Danhong
    2020, 43(9):64-72. DOI: 10.11835/j.issn.1000-582X.2020.09.007
    [Abstract](563) [HTML](477) [PDF 1.70 M](650)
    Abstract:
    MEMS-IMU includes a tri-axial gyroscope and a tri-axial accelerometer, in which gyroscope's noises lead to MEMS-IMU's orientation inaccurate and result in external accelerations presenting errors. Based on the problem, a method of removing gyroscope's noises in real time is proposed. The third column of directioncosine matrix and gyroscope's bias are taken as state vector so that gyroscope's noises could be obtained online. Both the external accelerations and measurement noises of accelerometer are regarded as measurement residuals so as to measure the gravity vector in any trajectory. A Kalman filter is utilized to fuse the measurement results of gyroscope and accelerometer, in which the former results is used to estimate the state vector and the latter results is aimed to calibrate the state vector. The feasibility of this study is verified by comparing orientation and external accelerations when MEMS-IMU is in arbitrary quasi-static. Experimental results show the maximum errors of pitch, roll, yaw and external accelerations are 0.5°, 0.2°, 2° and 0.2 m/s2 respectively, which are much better than that only based on gyroscope.
    8  Research on irregular flight recovery based on minimumcost flow model
    LI Yanlong BU Peng YU Fei ZHANG Yue ZHANG Xin
    2020, 43(9):73-80. DOI: 10.11835/j.issn.1000-582X.2020.09.008
    [Abstract](499) [HTML](832) [PDF 1.01 M](671)
    Abstract:
    The occurrence of unexpected incidents will cause flight plan failure to be carried out as planned,which will bring huge losses to airlines and passengers. In addition to the complexity of related factors, the difficulty in the flight recovery problem is mainly reflected in the immediacy of the recovery scheme.Therefore, in order to propose a quick and effective flight recovery plan to reduce the related losses, this paper described the recovery of irregular flight through space-time network technology, and realized the tracking of flights in space and time. Based on the minimumcost flow model, an integer programming model with the minimum delay time as the objective function was established. The model also considered the scheduling strategies of flight delay, aircraft replacement and flight cancellation. The Floyd-Warshall algorithm was proposed to solving the established model. Finally, the model and algorithm were verified by an example. The results show that for the emergency situation, the model and algorithm established in this paper can provide a reasonable flight recovery scheme, and the model and algorithm are feasible and availability. The model established in this paper has a general applicability, and it has certain reference significance for the study of the problem of recovery of abnormal flights.
    9  Distributed controller placement in SDN based on network partitioning
    WANG Kun LU Guanghong XU Lin YANG Han
    2020, 43(9):81-92. DOI: 10.11835/j.issn.1000-582X.2020.09.009
    [Abstract](557) [HTML](492) [PDF 1.04 M](705)
    Abstract:
    In this paper, the problem of distributed controller deployment in large-scale SDN(softwate defined networking) network is addressed. Aiming at improving resilience and reliability, a two stage controller placement (TSCP) method was proposed. The control domain was divided by the similarity of node to enhance the connectivity among device in the control domain for improving the resilience. Controller set with the minimum average rate of control path loss was selected as the controller placement for improving the reliability. By constraining the size of control domain and the propagation delay among equipment (switch or controller), the number of switch in control domain was made equalized and the controller placement reasonable. With the performance indexes defined, the comparison of GCP algorithm and K*-means algorithm with TSCP algorithm was made by experiments, and the results showed that TSCP algorithm could optimize the scale of control domain, balance the number of switches in control domain and reduce the number of controllers, thus performing better in network elasticity and reliability.
    10  Fault diagnosis of multi-sensor signal with unknown composite fault based on deep learning
    XING Liwen YAO Wenkai HUANG Ying
    2020, 43(9):93-100. DOI: 10.11835/j.issn.1000-582X.2020.09.010
    [Abstract](727) [HTML](1322) [PDF 1.62 M](928)
    Abstract:
    Deep learning has been widely used in the field of fault diagnosis, among which convolution neural networks (CNN) and long short-term memory networks (LSTM) are typical models. As a common method of multi-sensor signal fault diagnosis, CNN can obtain good diagnosis effect, but it can not diagnose unknown composite fault. In order to solve this problem, a CNN-LSTM-FCM(fuzzy C-means) model was proposed. Since LSTM was more sensitive to the time signals with the connection between the front and the back, it was combined with CNN to realize the diagnosis of unknown signals. The decoupling of composite fault was achieved through the probability classification output. The CNN-LSTM-FCM model itself had optimized parameter design, which further improved the diagnosis accuracy. The chemical process fault measurement data was used for experiments, and the results showed that the diagnostic accuracy of CNN-LSTM-FCM model could reach 97.15%, which was superior to both CNN model and LSTM model, thus having a high application value in fault diagnosis.
    11  Load transfer model considering over-consolidation ratio and Poisson effect
    OU Mingxi DAI Zhifeng CHEN Yinghui DING Zude
    2020, 43(9):101-108. DOI: 10.11835/j.issn.1000-582X.2020.223
    [Abstract](431) [HTML](752) [PDF 1.44 M](636)
    Abstract:
    In order to analyze the influence of over-consolidation state and Poisson effect on shear characteristics of sand-pipe pile interface, load transfer model was established on the basis of traditional hyperbolic model, in which lateral earth pressure coefficient of the over-consolidation ratio and the increase of lateral earth pressure caused by Poisson effect were considered, and the reliability of calculation model was verified by existing model test results. Also the influence factors on limit friction stress were analyzed by an example, and the results showed that the ultimate frictional resistance of compressive piles and uplift piles increased linearly with the increase of over-consolidation ratio from 1.0 to 3.0, and the increases range was 83.6% and 92.9% respectively; the ultimate frictional resistance of compressive piles increased linearly with the increase of poisson ratio from 0.1 to 0.3, and the increase range was 3.5%, while the uplift piles decreased linearly with the increase of Poisson ratio, and the decrease range was 3.6%; with the pile-soil modulus ratio increase from 300 to 1 500, the ultimate frictional resistance of compressive piles decreased about 7.6%, and the uplift piles increased about 9.6%.
    12  Groundwater dynamic simulation and maximum water level predictionof Erqi business district in Wuhan
    YUAN Guangkun
    2020, 43(9):109-117. DOI: 10.11835/j.issn.1000-582X.2020.09.012
    [Abstract](519) [HTML](780) [PDF 3.23 M](663)
    Abstract:
    FEFLOW numerical simulation software was employed to simulate the dynamic changes of groundwater of Hankou district, Wuhan. The regional model was used to provide boundary conditions for Erqi business district so as to construct the refined model of groundwater dynamic change in the studied area. The highest water level of confined aquifer got by simulation was 27.5 m around the flood control wall of the Yangtze river in the east of business district. The groundwater level gradually decreased from east to west, and finally dropped to 22.0~25.9 m within the business district. The research results can provide reasonable anti-floating fortification water level for anti-floating design in the area, furnishing the basis for accurate calculation of groundwater buoyancy.
    13  Mixed fruit fly algorithm and its application in combinatorial optimization
    LI Yancang HAN Muxuan
    2020, 43(9):118-130. DOI: 10.11835/j.issn.1000-582X.2020.226
    [Abstract](457) [HTML](1029) [PDF 2.83 M](642)
    Abstract:
    To overcome the defects of local optimum and precocity in basic fruit fly algorithm, an improved drosophila algorithm was presented in this paper for optimization. The basic idea is to improve the searching ability and accuracy of the algorithm by using the self-non-self antigen recognition mechanism of immune algorithm and the knowledge processing mechanism of learning-memory-forgetting in immune system. The immune response is introduced at the later stage of fruit fly algorithm implementation and the population diversity is enhanced by producing different antibodies to jump out of the local optimum. The results of numerical simulation and practical cases show that the improved algorithm performs better, and it provides an effective and feasible method and idea for algorithm optimization.

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