An Active Construction Dynamic Schedule Management Model: Using the Fuzzy Earned Value Management and BP Neural Network

Fangfang Yu,Xiaobo Chen,Clark A. Cory,Zhixuan Yang,Yingwen Hu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.7

Project schedule management is an important aspect of project management. Earned value management (EVM) and its extension methods are widely adopted in project schedule management in various previous studies, however, most of these studies adopted schedule performance indicators based on definiteness condition and historical data, which ignored the impact of uncertainty and dynamics. So the decision risk in schedule management has been increased dramatically. Therefore, this paper proposed an active construction dynamic schedule management model based on fuzzy earned value management (F-EVM) and BP neural network (BP-NN). Firstly, the fuzzy theory was introduced into EVM to evaluate the schedule performance when the project finish schedule cannot be deterministic expression. Then, the main resource planning was functioned as input variables to predict the schedule in advance through BP-NN. Finally, the future action plans was adjusted based on the results to achieve active control of the project schedule. The case results indicated that the introduction of F-EVM effectively reduced influence of subjective estimation on uncertainty in the data measurement process. And the proposed dynamic schedule management model gave a 32.06% better mean absolute percentage error (MAPE) than the existing methods for estimated project duration. Hence, the proposed model provided a more accurate estimation of the project duration and considered the uncertainty and dynamics of the construction project, thereby achieving more effective management of project schedule.

Large deviations for dependent heavy tailed random variables

Yu Miao,Tianyu Xue,Ke Wang,Fangfang Zhao 한국통계학회 2012 Journal of the Korean Statistical Society Vol.41 No.2

Let {Xn, n ≥ 1} be a stationary sequence of random variables with heavy tails. In this paper,we study the logarithmic asymptotic behaviors for the distributions of the partial sums Sn = ni =1 Xi under the assumption that {Xn, n ≥ 1} is a sequence of dependent random variables. Our main interest is in the crude estimates P(|Sn| > nx) ≈ n−αx+1 for appropriate values x where α is a specific parameter. Some results in this paper extend the works of Hu and Nyrhinen (2004).

Experimental Study on Mechanical Performance and Microstructure of Polypropylene Fiber Recycled Concrete

Fangfang Wei,Liping Li,Yu Zhu,Youzheng Zhao 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.7

Recycled concrete reinforced by polypropylene fibers boosts an alternative sustainable solution to address the need of reusing waste concrete. This paper reports experimental and analytical studies of static and dynamic comprehensive behavior on recycled concrete specimens reinforced with different contents of polypropylene fiber (PPF). Electro-hydraulic pressure testing was used to obtain static compressive strength, whereas 74 mm diameter Split HopkinsonPressure Bar (SHPB) was applied for dynamic impact compression tests at four strain rates. In addition, the reinforcing mechanism of polypropylene fiber on recycled concrete was analyzed of the micro-structure through Scanning Electron Microscope (SEM). Finally, ANSYS/LS-DYNA was applied for the simulation of the SHPB test, which was validated by good agreements of the stress waveform and failure modes of the fiber-reinforced recycled concrete specimen during the impact test. It appears that polypropylene fiber can optimize the microscopic pore structure inside the concrete, thus effectively improving the mechanical properties of recycled concrete which were originally defected by recycled aggregate. Also, higher strain rates significantly increase dynamic compressive strength as well as impact toughness. This study shows that the optimal content of polypropylene fiber in recycled concrete is 0.1% − 0.2%. The numerical simulation by ANSYS/LS-DYNA further proved that the HOLMQUIST-JOHNSON-COOK (HJC) constitutive model can better reflect the dynamic performance of concrete.

Predicting Urban Tourism Flow with Tourism Digital Footprints Based on Deep Learning

Fangfang Gu,Keshen Jiang,Yu Ding,Xuexiu Fan 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.4

Tourism flow is not only the manifestation of tourists’ special displacement change, but also an important driving mode of regional connection. It has been considered as one of significantly topics in many applications. The existing research on tourism flow prediction based on tourist number or statistical model is not in-depth enough or ignores the nonlinearity and complexity of tourism flow. In this paper, taking Nanjing as an example, we propose a prediction method of urban tourism flow based on deep learning methods using travel diaries of domestic tourists. Our proposed method can extract the spatio-temporal dependence relationship of tourism flow and further forecast the tourism flow to attractions for every day of the year or for every time period of the day. Experimental results show that our proposed method is slightly better than other benchmark models in terms of prediction accuracy, especially in predicting seasonal trends. The proposed method has practical significance in preventing tourists unnecessary crowding and saving a lot of queuing time.

Central limit theorems for LS estimators in the EV regression model with dependent measurements

Yu Miao,Fangfang Zhao,Ke Wang 한국통계학회 2011 Journal of the Korean Statistical Society Vol.40 No.3

In this paper, we consider the simple linear errors-in-variables (EV) regression models:η_i = θ + βx_i + ε_i, ξ_i = x_i + δ_i, 1 ≤ i ≤ n, where θ, β, x_1, x_2, . . . are unknown constants (parameters), (ε_1, δ_1), (ε_2, δ_2), . . . are errors and ξ_i, η_i, i = 1, 2, . . . are observable. The asymptotic normality for the least square (LS) estimators of the unknown parameters βand θ in the model are established under the assumptions that the errors arem-dependent,martingale differences, φ-mixing, ρ-mixing and α-mixing.

Reliability Enhancement for Multimedia Delivery in Caching-Assisted MmWave HetNets

Yin, Fangfang,Wang, An,Zhang, Yu,Liu, Danpu,Jin, Libiao 한국통신학회 2023 Journal of communications and networks Vol.25 No.3

Explosive growth of bandwidth-intensive multime-dia applications may impose a heavy traffic burden on wirelesslinks of heterogeneous networks (HetNets), which also requiressubstantial energy consumption. Edge caching is emerging toreduce the service latency and relieve the huge burden on thebackhaul links in HetNets. Moreover, millimeter wave (mmWave)spectrum with huge available bandwidth has been regarded asa promising technology to satisfy the high capacity demands infuture HetNets. However, the high directionality coupled withharsh propagation environment makes mmWave communicationvulnerable to blockage, which makes link establishment andmaintenance challenging. In this paper, we propose a jointmaximum distance separable (MDS) coded caching and trans-mission problem for a mmWave HetNet, aiming at minimizingthe backhaul energy consumption while satisfying users’ qualityof service (QoS) requirements on high data rate. The formulatedmixed integer non-linear programming (MINLP) problem issolved by decomposing it into two stages of subproblems. Inthe first stage, the convex optimization technique is applied totackle the coded caching subproblem. Subsequently, we proposetwo efficient algorithms based on matching in the second stageto deal with the transmission subproblem. Simulation resultsdemonstrate that the proposed schemes can effectively maximizethe backhaul energy saving and enhance the download ratecompared with the benchmark scheme.

Deformation Characteristics and Determination of Optimum Supporting Time of Alteration Rock Mass in Deep Mine

Weijian Yu,Bao Pan,Fang Zhang,Shufu Yao,Fangfang Liu 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.11

In the tectonic belt, the stability of surrounding metamorphic rock was studied systematically using field investigation, laboratory analysis, theoretical derivation and engineering application. Based on the Jinchuan Mine geological conditions, the exposed surrounding rock of the roadway and its deformed features were analysed. The results of X-ray diffraction and scanning electron microscopy shows that the microstructures of altered rocks affected by structural belts were significant loose, the fractures and pores were well developed, and the composition of clay minerals was more abundant. Then, A nonlinear rheological constitutive model based on the modified Nishihara model is deduced. The actual monitoring data and the rheological parameters of the surrounding rock mass in the Jinchuan Mine area were determined. And these data were used to obtain the optimum secondary-support time by inverse analysis. Finally, the joint support technology of bolt and anchor cable was proposed. The field practice shows that this support method is favourable to the long-term stability of roadway and can effectively reduce the deformation of roadway surrounding rock.

Global Output Feedback Regulation of Uncertain Nonlinear Systems with Unknown Time Delay

Weiyong Yu,Shutang Liu,Fangfang Zhang 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.2

This paper investigates the problem of global output feedback regulation for a class of nonlinear systems with unknown time delay. It is also allowed to contain uncertain functions of all the states and input as long as the uncertainties satisfying certain bounded condition for the considered systems. In this paper, a constructive control technique has been proposed for controlling the systems. By using dynamic high-gain scaling approach and choosing an appropriate Lyapunov-Krasovskii functional, a delay-independent robust adaptive output feedback controller is constructed such that the states of the considered systems achieve global regulation. Two simulation examples are provided to demonstrate the effectiveness of the proposed design scheme.

Research on a Dynamic E-commerce System based on Middleware Technology and Web Service

Changai Chen,Fangfang Geng,Jiayun Zhang,Yu Zhao 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.9

With the continuous development of information technology and the growing popularity of the Internet, the E-commerce system based on the traditional distributed technology has exposed more and more problems and the development of dynamic E-commerce system has become the target of the next generation of E-commerce. Middleware technology is the trend of the development of software, which is famed and the software developing fastest. So the middleware technology is used to develop the E-commerce system in order to propose a new generation dynamic E-commerce system. Several key techniques J2EE architecture and MVC design pattern are introduced. Then a service-oriented architecture(SOA) and a service-oriented dynamic E-commerce system based on middleware technology and web services are researched and designed. Web services can provide exchange of information and system integration for dynamic E-commerce, support more complex types of web interaction and collaboration. J2EE technology and MVC design pattern can simplify the software development, improve the software performance and quickly construct the dynamic E-commerce system with the good expansibility, maintainability, dependability and high usability.

Curcumin Alleviates the Side Effects of Cisplatin on Gastric Emptying of Mice by Inhibiting the Signal Changes of Acetylcholine and Interstitial Cells of Cajal

Hui Li,Wenhua Xu,Xuying Liu,Junli Ye,Peijie Li,Fangfang Shang,Xiaoling Yu 한국식품영양과학회 2020 Journal of medicinal food Vol.23 No.9

Cisplatin is a widely used anticancer drug that has adverse effects on gastrointestinal function. Curcumin is a natural polyphenol extracted from the rhizome of turmeric that has a wide range of biological activities. The present study investigated the effects of cisplatin on gastric emptying in mice and examined whether these can be inhibited by curcumin. We found that pretreatment with curcumin (200 mg/kg/day) for 10–30 days partly inhibited the decreases in gastric emptying rate and body weight induced by cisplatin. Furthermore, cisplatin reduced acetylcholine (ACh) concentration and the messenger RNA (mRNA) level of ACh receptor (AChR) as well as acetylcholinesterase activity in the stomach of mice; caused ultrastructural damage to interstitial cells of Cajal (ICC); and altered the expression of c-kit/stem cell factor and the gap junction protein connexin 43 in ICC. Curcumin pretreatment inhibited the effects of cisplatin on ACh indicators and ICC. These results demonstrate that curcumin can protect against cisplatin-induced gastric emptying disorder and thus has therapeutic potential for alleviating this condition in cancer patients receiving cisplatin chemotherapy.