On the plane geometry design method of the loop-free hyperbolic single-layer cable structures

Renjie Liu,Jiajia Cao,Hang Zhao,Su-Duo Xue,Guangyong Wang,Jin Liang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.10

The plane geometry design of the cable-net structure is the basis for the form-finding and structural design. The loop-free single-layer cable-net structure is a new cable-net scheme, but due to its special and complex shape, it is difficult to determine its plane geometry according to architectural requirements. In this paper, the moving support node method is proposed, which can quickly get the plane geometry of a loop-free single-layer cable-net structure. The form-finding is proceeded based on the existing small elastic modulus method. There are two constraints when using the moving support node method. One is that the projection of all cables is straight line, and the other is that the distance between the two cables of each support node and the inner boundary of the target is equal. The aim is to minimize the sum of the distances from all cables to the inner boundary of the target. Using the plane geometry control parameters and the plane coordinates of the support nodes as decision variables, the plane geometry closest to the target inner and outer boundaries is get through optimization analysis. According to the derivation of the formula, the plane projection shape of a loop-free single-layer cable-net structure is mainly related to three parameters, including the number of supports, the difference between the node numbers of the supports at both ends of each cable, and the target curve equations of the inner and outer boundaries. Finally, taking the roof structure of Linyi Olympic Stadium as an instance, the feasibility of the plane geometry design method of the loop-free single-layer cable-net structures based on the moving support node method is verified.

Experimental research on machining characteristics of SiC ceramic with end electric discharge milling

Renjie Ji,Yonghong Liu,Yanzhen Zhang,Xin Dong,Zhili Chen,Baoping Cai 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.6

Silicon carbide (SiC) ceramic has been widely used in modern industry. However, the beneficial properties of SiC ceramic make machining difficult and costly by conventional machining methods. This paper proposes a new process of machining SiC ceramic using end electric discharge (ED) milling. The process is able to effectively machine a large surface area on SiC ceramic at low cost and no environmental pollution. The effects of emulsion concentration, emulsion flux, milling depth, copper electrode number, and copper electrode diameter on the process performance such as the material removal rate, electrode wear ratio, and surface roughness have been investigated. In addition, the microstructure of the machined surface is examined with a scanning electron microscope, and the material removal mechanism of SiC ceramic during end ED milling is obtained.

Effect of machining parameters on surface integrity of silicon carbide ceramic using end electric discharge milling and mechanical grinding hybrid machining

Renjie Ji,Yonghong Liu,Yanzhen Zhang,Baoping Cai,Xiaopeng Li,Chao Zheng 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.1

A novel hybrid process that integrates end electric discharge (ED) milling and mechanical grinding is proposed. The process is able to effectively machine a large surface area on SiC ceramic with good surface quality and fine working environmental practice. The polarity, pulse on-time, and peak current are varied to explore their effects on the surface integrity, such as surface morphology, surface roughness, micro-cracks, and composition on the machined surface. The results show that positive tool polarity, short pulse on-time, and low peak current cause a fine surface finish. During the hybrid machining of SiC ceramic, the material is mainly removed by end ED milling at rough machining mode, whereas it is mainly removed by mechanical grinding at finish machining mode. Moreover, the material from the tool can transfer to the workpiece, and a combination reaction takes place during machining.

Analyzing the Impact of the Internet on Higher Education

Renjie Zhou,Dongchen Xia,Yuyu Yin,Jilin Zhang,Wei Zhang,Jin Feng 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.6

The Internet has gone deeply into nowadays college students’ life, and has become an important platform for students to study, entertainment, and build social relationships. In this paper, we study the patterns of how college students use the Internet, and analyze the potential impacts of Internet on the living and education of college students. We find that 95% of college students spend more than two hours online per day. Academic and career development is the top motivation for college students to use the Internet. However, high percentage of the college students is not able to control their usage of the Internet well, which leading to recognition that the Internet is a negative factor that affects their course performance. The findings are helpful for educators to guide students to use Internet in a reasonable way and to find ways to make the Internet to be conducive to high quality of higher education.

On the Collapse Resistance of the Levy Type and the Loop-Free Suspen-Dome Structures After Accidental Failure of Cables

Renjie Liu,Yao Zou,Guangyong Wang,Suduo Xue 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.2

Current Levy type suspen-domes use loop cables which are key elements and carry large tensions. The loop-free suspendome was proposed for improving the collapse resistance and reducing cable tensions. However, the collapse resistance of the loop-free suspen-dome after accidental failure of cables has not been verifi ed and its key element is not clear. In this paper, analysis on the collapse resistance of both the Levy type suspen-dome and the loop-free suspen-dome after accidental failure of cables is performed based on the AP method by considering dynamic eff ect and non-linearity. The displacements and residual bearing capacity of 34 cable-rupture schemes are discussed, the eff ect on the cable tension and failure mode are also analyzed. It turns out that collapse resistance of the loop-free suspen-dome is better than the Levy type suspen-dome. The failure of cables does not infl uence the tension of remaining cables obviously so that the loop-free cable-strut system has suffi cient stiff ness and provides support and restraint for the reticulated shell. The most important cable in the loop-free suspen-dome is located in the outermost layer of the cable-strut system. It is also found that whether progressive collapse of the suspen-dome occurs after accidental failure of cables depends on both the bearing capacity of the reticulated shell and the residual contribution of the cable-strut system.

Unconstrained Face Verification by Optimally Organizing Multiple Classifiers

Renjie Huang,Tao Li,Yumin Dou,Mao Ye 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.4

Face verification is still a difficult problem in badly uncontrolled conditions. Motivated by the observation that failure of facial image pair-matching is always caused by inconsistent visual con-ditions of both total face and face parts, we propose to train multiple classifiers on total face and face parts with respect to different visual consistency conditions. For training these classifiers, multiple similarity measures of multiple features on the matched and mismatched face image pairs are consid-ered as the positive and negative training samples respectively. For a new face image pair, we compute its similarity measures and visual consistency measures (VCM). Relying on these VCMs, we adap-tively select VCM-specific classifiers and optimally organize them to form an ensemble by the reliabil-ity estimation and adaptively weighting combination. Our contributions are the visual consistency measure and the optimally organized VCM-specific classifier ensemble which can better overcome the influence of uncontrolled factors such as pose, illumination and expression etc. Experiments on the challenging unconstrained face dataset LFW (Labeled Face in the Wild) confirm the good performance of our algorithm with the record 0.8927 compared with state-of-the-art approaches in the same experiment settings.

Fuzzy Synthetic Evaluation of Relay Protection based on Variable Weight Value

Renjie Song,Yuming Chen 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.11

To improve the accuracy of the state evaluation is the most important for the relay protection state maintenance. Therefore, a fuzzy synthetic evaluation of relay protection based on variable weight value is proposed in this paper. Pick up the major factor of the device and secondary circuit of relay protection to establish a reasonable index system of state evaluation. Then according to the variable weight comprehensive concept of factor space theory, we introduce the balance function to adjust the weight coefficient of each factor. Final, get the membership function in triangle trapezoid distribution to show the condition information, and select synthetic operator, then an evaluation system of relay protection with objectively and accurately is proposed. Running examples show that after dealing with the variable weight, some factors weight value become larger or smaller, so running state of evaluate factor may be changed, make it close to the real running state.

Treatment of wastewater containing linear alkylbenzene sulfonate by bacterial-microalgal biological turntable

Renjie Tu,Wenbiao Jin,Song-fang Han,Binbin Ding,Shu-hong Gao,Xu Zhou,Shao-feng Li,Xiaochi Feng,Qing Wang,Qinhui Yang,Yu Yuwen 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.5

Linear alkylbenzene sulfonate (LAS), which is widely used as detergent, is a common toxic pollutant in wastewater. Generally, biodegradation process is applied to remove LAS. However, the efficiency of traditional wastewater treatment cannot meet the growing demand. In this study, an improved biological turntable with a symbiotic system of bacteria and microalgae was primarily used to enhance the biodegradation efficiency of LAS from wastewater. The symbiotic system of bacteria and microalgae was mainly composed of Scenedesmus dimorphus and three LAS-degrading bacteria Plesiomonas sp. (L3, L7) and Pseudomonas sp. (H6). The average removal rate of LAS was up to 94.6%. The LAS concentration of the effluent of the system decreased by 81.7% after the bacterial-microalgae inoculation (the inoculation temperature was 25 oC; microalgae were inoculated at a concentration of 10% only at the start of the system; bacteria were continuously inoculated at 1‰ concentration). After bacterial-microalgae inoculation, the average effluent concentration of CODCr in the tertiary reaction tank was 24.3mg/L, the average membrane effluent concentration was 15.8mg/L, and the average removal rate was 90.5%. Compared with the control group without inoculation, the concentration of CODCr in the tertiary reaction tank and membrane effluent decreased by 55.7% and 46.4%. The denaturing gradient electrophoresis (DGGE) pattern analysis of the systemic flora showed that there were two dominant species of high LAS degrading bacteria. They were identified to belong to Plesiomonas sp. and Pseudomonas sp., respectively.

The View Growth Pattern of User Generated Videos on YouTube

Renjie Zhou,Dongchen Xia,Yuyu Yin,Jilin Zhang,Wei Zhang 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.6

With the rapid development of social media, video sharing sites like YouTube are getting more and more attention. Discovering the view growth pattern have become interesting topics for researchers as well as advertisers, media companies. In this paper, we analyze two aspects about video view growth pattern of YouTube videos. Firstly, the pattern of aggregated view is studied. It is found that the aggregated view rate peaks in the first few days, and falls quickly in the following days, and then decrease slowly during the consecutive weeks. Finally, the view rate tends to be a constant on the long run. The aggregated view count after a period of two months can be fitted with a linear line. Secondly, the view growth pattern of individual video is explored. The results indicate that the majority of videos peak at the very beginning of videos’ lifetime, and the category of view sources causes the peak is different. The view count of individual video and the view count from each source item also stabilize after a period of two months, and we finally show the referring time and active period of each source item.

Controllable Curve Fitting Based Swing Door Trending Algorithm and its Application in Process Data Compression

Song Renjie,Zhang Qinghe,Liu Haiyang,Yang Shuo,Wang Zhaohui,Bao Zhen 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.11

Swing door trending (SDT) algorithm is a lossy compression algorithm that be applied on the real-time database and proposed by OSI software company of American; SDT is widely used to compress process data generated by process industry. Using straight line for a data section to linear fitting in traditional SDT algorithm. However, the data generated in the process of industrial production are slightly fluctuating with time. So, the use of linear fitting will lead to a large decompression error. In order to overcome the large decompression error generated by the traditional SDT, we proposed Controllable Curve Fitting Based Swing Door Trending (CCFSDT). The CCFSDT algorithm uses curve line for a data section to fitting, the data restored are closer to the true value. And in order to reduce the cost of curve fitting, it can be appropriate to reduce the total number of points of curve fitting. We filter noise point before fitting to void the impact on the reduction data and achieve better compression effect. The experimental results on simulated data and actual plant data show that: under the same conditions, the CCFSDT can well reduce the errors of decompression and achieve satisfactory performance.