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Split-order consolidation optimization for online supermarkets: Process analysis and optimization models

《工程管理前沿（英文）》页码 499-516 doi: 10.1007/s42524-022-0221-5

摘要： The large-scale online supermarket is a newly emerging online retailing mode which brings great convenience to people. Online supermarkets are characterized by having large amounts of daily orders with potentially multiple items, diverse delivery times, and a high order-split rate. Multiple shipments for one order caused by order splitting result in high cost and disturbance and a large number of discarded consumable packages at online retailers and customers, causing severe damage to the environment. Accordingly, research on split-order consolidation fulfilment is critical for the advancement of the practice and theory in the context of highly complex online retailing. This paper first analyzes the characteristics and the challenges associated with the split-order consolidation problem that online supermarket is confronting and summarizes the new operational process of split-order consolidation fulfilment. Then, a time–space network optimization model is built, and its corresponding solution algorithm is presented to solve the questions of where and when to consolidate the split orders. Finally, the computation results of the numerical experiments are provided to verify the effectiveness of the algorithm, and a sensitivity analysis of the relevant parameters is performed. This work highlights the effect of order consolidation processes and fulfilment methods on the order fulfilment decision-making for online supermarkets. The purpose of this article is to help pave the way for more effective online supermarket management and order implementation.

关键词： online supermarkets split-order consolidation time–space network genetic algorithm

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FULL TIME-SPACE GOVERNANCE STRATEGY AND TECHNOLOGY FOR CROPLAND NON-POINT POLLUTION CONTROL IN CHINA

《农业科学与工程前沿（英文）》 2023年第10卷第4期页码 593-606 doi: 10.15302/J-FASE-2023522

摘要：

Ensuring food safety while reducing agricultural non-point source pollution is quite challenging, especially in developing and underdeveloped countries. Effective systematic strategies and comprehensive technologies need to be developed for agricultural non-point source pollution control at the watershed scale to improve surface water quality. In this review, a proposal is made for a full time-space governance strategy that prioritizes source management followed by endpoint water pollution control. The 4R chain technology system is specifically reviewed, including source reduction, process retention, nutrient reuse and water restoration. The 4R chain technology system with the full time-space governance strategy was applied at the scale of an administrative village and proved to be a feasible solution for reducing agricultural non-point source pollution in China. In the future, a monitoring system needs to be established to trace N and P transport. Additionally, new smart fertilizer and intelligent equipment need to be developed, and relevant governance standards and supportive policies need to be set to enhance the efficacy of agricultural non-point source pollution control.

关键词： 4R chain technology system agricultural non-point source pollution case study full time-space governance strategy

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A time−space porosity computational model for concrete under sulfate attack

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0985-7

摘要： The deterioration of the microscopic pore structure of concrete under external sulfate attack (ESA) is a primary cause of degradation. Nevertheless, little effort has been invested in exploring the temporal and spatial development of the porosity of concrete under ESA. This study proposes a mechanical–chemical model to simulate the spatiotemporal distribution of the porosity. A relationship between the corrosion damage and amount of ettringite is proposed based on the theory of volume expansion. In addition, the expansion strain at the macro-scale is obtained using a stress analysis model of composite concentric sphere elements and the micromechanical mean-field approach. Finally, considering the influence of corrosion damage and cement hydration on the diffusion of sulfate ions, the expansion deformation and porosity space−time distribution are obtained using the finite difference method. The results demonstrate that the expansion strains calculated using the suggested model agree well with previously reported experimental results. Moreover, the tricalcium aluminate concentration, initial elastic modulus of cement paste, corrosion damage, and continuous hydration of cement significantly affect concrete under ESA. The proposed model can forecast and assess the porosity of concrete covers and provide a credible approach for determining the residual life of concrete structures under ESA.

关键词： expansion deformation porosity internal expansion stress external sulfate attack mechanical–chemical coupling model

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Efficient detection methods for amplify-and-forward relay-aided device-to-device systems with full-rate space-time Article

Kang-li ZHANG, Cong ZHANG, Fang-lin GU, Jian WANG

《信息与电子工程前沿（英文）》 2017年第18卷第6期页码 788-795 doi: 10.1631/FITEE.1700018

摘要：中继辅助设备到设备通信是下一代蜂窝网络中一项极具潜力的技术。研究了适用于配置多天线的放大转发中继辅助设备到设备通信系统的不同传输方案。为了解决基于全速率空时块码传输方案的传统最大似然检测算法复杂度高的问题，文中提出两种低复杂度检测方法，分别为采用最大似然合并算法的检测方法和采用联合条件最大似然检测器的检测方法。特别是，所提的基于联合条件最大似然检测器的检测方法，能够通过牺牲一定的存储空间换取较好的并行处理能力。仿真结果表明：针对采用全速率空时块码传输方案提出的两种检测方法，能够获得与传统最大似然检测方法近乎相同的误符号率，但所提检测方法复杂度更低；同时，采用基于全速率空时块码的传输方案比复用传输方案具有更优的误码性能。仿真结果还进一步验证了对所提检测方法的分集增益分析。

关键词：设备到设备通信；中继；检测；全速率空时块码

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我国天地一体化航天互联网构想

沈荣骏

《中国工程科学》 2006年第8卷第10期页码 19-30

摘要：

地面互联网技术的快速发展以及航天任务的复杂性不断提高，产生了将互联网扩展到空间、建立天地一体化航天互联网的强烈需求，并提供了实现的技术可能性。探讨了我国航天任务中存在的不同卫星天地协议不统一、航天任务数据不能共享、资源综合利用率低等问题，分析了对未来任务的需求，阐述了建设我国天地一体化航天互联网的重要意义；介绍了国外航天互联网发展状况；提出了我国天地一体化航天互联网的总体目标、组成、网络体系结构及网络协议的初步构想；分析了需要突破的关键技术；最后提出了发展步骤建议。

关键词：一体化航天互联网体系结构网络协议发展步骤

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Negative weights in network time model

Zoltán A. VATTAI, Levente MÁLYUSZ

《工程管理前沿（英文）》 2022年第9卷第2期页码 268-280 doi: 10.1007/s42524-020-0109-1

摘要： Time does not go backward. A negative duration, such as “time period” at first sight is difficult to interpret. Previous network techniques (CPM/PERT/PDM) did not support negative parameters and/or loops (potentially necessitating recursive calculations) in the model because of the limited computing and data storage capabilities of early computers. Monsieur Roy and John Fondahl implicitly introduced negative weights into network techniques to represent activities with fixed or estimated durations (MPM/PDM). Subsequently, the introduction of negative lead and/or lag times by software developers (IBM) apparently overcome the limitation of not allowing negative time parameters in time model. Referring to general digraph (Event on Node) representation where activities are represented by pairs of nodes and pairwise relative time restrictions are represented by weighted arrows, we can release most restraints in constructing the graph structure (incorporating the dynamic model of the inner logic of time plan), and a surprisingly flexible and handy network model can be developed that provides all the advantages of the abovementioned techniques. This paper aims to review the theoretical possibilities and technical interpretations (and use) of negative weights in network time models and discuss approximately 20 types of time-based restrictions among the activities of construction projects. We focus on pure relative time models, without considering other restrictions (such as calendar data, time-cost trade-off, resource allocation or other constraints).

关键词： graph technique network technique construction management scheduling

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Understanding network travel time reliability with on-demand ride service data

Xiqun (Michael) CHEN, Xiaowei CHEN, Hongyu ZHENG, Chuqiao CHEN

《工程管理前沿（英文）》 2017年第4卷第4期页码 388-398 doi: 10.15302/J-FEM-2017046

摘要： Travel time reliability is of increasing importance for travelers, shippers, and transportation managers because traffic congestion has become worse in major urban areas in recent years. To better evaluate the urban network-wide travel time reliability, five indices based on the emerging on-demand ride service data are proposed: network free flow time rate (NFFTR), network travel time rate (NTTR), network planning time rate (NPTR), network buffer time rate (NBTR), and network buffer time rate index (NBTRI). These indices take into account the probability distribution of the travel time rate (i.e., travel time spent for the unit distance, in min/km) of each origin-destination (OD) pair in the road network. We use real-world data extracted from DiDi-Chuxing, which is the largest on-demand ride service platform in China. For demonstrative purposes, the network-wide travel time reliability of Beijing is analyzed in detail from two dimensions of time and space. The results show that the road network is more unreliable in AM/PM peaks than other time periods, and the most reliable time period is the early morning. Additionally, we can find that the central region is more unreliable than other regions of the city based on the spatial analysis results. The proposed network travel time reliability indices provide insights for the comprehensive evaluation of the road network traffic dynamics and day-to-day travel time variations.

关键词： network travel time reliability on-demand ride services travel time rate OD

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Virtual network embedding based on real-time topological attributes

Jian DING,Tao HUANG,Jiang LIU,Yun-jie LIU

《信息与电子工程前沿（英文）》 2015年第16卷第2期页码 109-118 doi: 10.1631/FITEE.1400147

摘要： As a great challenge of network virtualization, virtual network embedding/mapping is increasingly important. It aims to successfully and efficiently assign the nodes and links of a virtual network (VN) onto a shared substrate network. The problem has been proved to be NP-hard and some heuristic algorithms have been proposed. However, most of the algorithms use only the local information of a node, such as CPU capacity and bandwidth, to determine how to map a VN, without considering the topological attributes which may pose significant impact on the performance of the embedding. In this paper, a new embedding algorithm is proposed based on real-time topological attributes. The concept of betweenness centrality in graph theory is borrowed to sort the nodes of VNs, and the nodes of the substrate network are sorted according to the correlation properties between the former selected and unselected nodes. In this way, node mapping and link mapping can be well coupled. A simulator is built to evaluate the performance of the proposed virtual network embedding (VNE) algorithm. The results show that the new algorithm significantly increases the revenue/cost (R/C) ratio and acceptance ratio as well as reduces the runtime.

关键词： Virtual network embedding (VNE) Real-time topological attributes Betweenness centrality Correlation properties Network virtualization

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Real-time tool condition monitoring method based on temperature measurement and artificial neural network

《机械工程前沿（英文）》 doi: 10.1007/s11465-021-0661-3

摘要： Tool failures in machining processes often cause severe damages of workpieces and lead to large quantities of loss, making tool condition monitoring an important, urgent issue. However, problems such as practicability still remain in actual machining. Here, a real-time tool condition monitoring method integrated in an in situ fiber optic temperature measuring apparatus is proposed. A thermal simulation is conducted to investigate how the fluctuating cutting heats affect the measuring temperatures, and an intermittent cutting experiment is carried out, verifying that the apparatus can capture the rapid but slight temperature undulations. Fourier transform is carried out. The spectrum features are then selected and input into the artificial neural network for classification, and a caution is given if the tool is worn. A learning rate adaption algorithm is introduced, greatly reducing the dependence on initial parameters, making training convenient and flexible. The accuracy stays 90% and higher in variable argument processes. Furthermore, an application program with a graphical user interface is constructed to present real-time results, confirming the practicality.

关键词： tool condition monitoring cutting temperature neural network learning rate adaption

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Robust energy-efficient train speed profile optimization in a scenario-based position–time–speed network

《工程管理前沿（英文）》 2021年第8卷第4期页码 595-614 doi: 10.1007/s42524-021-0173-1

摘要： Train speed profile optimization is an efficient approach to reducing energy consumption in urban rail transit systems. Different from most existing studies that assume deterministic parameters as model inputs, this paper proposes a robust energy-efficient train speed profile optimization approach by considering the uncertainty of train modeling parameters. Specifically, we first construct a scenario-based position–time–speed (PTS) network by considering resistance parameters as discrete scenario-based random variables. Then, a percentile reliability model is proposed to generate a robust train speed profile, by which the scenario-based energy consumption is less than the model objective value at

α

confidence level. To solve the model efficiently, we present several algorithms to eliminate the infeasible nodes and arcs in the PTS network and propose a model reformulation strategy to transform the original model into an equivalent linear programming model. Lastly, on the basis of our field test data collected in Beijing metro Yizhuang line, a series of experiments are conducted to verify the effectiveness of the model and analyze the influences of parameter uncertainties on the generated train speed profile.

关键词： robust train speed profile percentile reliability model scenario-based position–time–speed network mixed-integer programming

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Time-series prediction based on global fuzzy measure in social networks

Li-ming YANG,Wei ZHANG,Yun-fang CHEN

《信息与电子工程前沿（英文）》 2015年第16卷第10期页码 805-816 doi: 10.1631/FITEE.1500025

摘要： Social network analysis (SNA) is among the hottest topics of current research. Most measurements of SNA methods are certainty oriented, while in reality, the uncertainties in relationships are widely spread to be overridden. In this paper, fuzzy concept is introduced to model the uncertainty, and a similarity metric is used to build a fuzzy relation model among individuals in the social network. The traditional social network is transformed into a fuzzy network by replacing the traditional relations with fuzzy relation and calculating the global fuzzy measure such as network density and centralization. Finally, the trend of fuzzy network evolution is analyzed and predicted with a fuzzy Markov chain. Experimental results demonstrate that the fuzzy network has more superiority than the traditional network in describing the network evolution process.

关键词： Time-series network Fuzzy network Fuzzy Markov chain

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Data-driven approach to solve vertical drain under time-dependent loading

《结构与土木工程前沿（英文）》 2021年第15卷第3期页码 696-711 doi: 10.1007/s11709-021-0727-7

摘要： Currently, the vertical drain consolidation problem is solved by numerous analytical solutions, such as time-dependent solutions and linear or parabolic radial drainage in the smear zone, and no artificial intelligence (AI) approach has been applied. Thus, in this study, a new hybrid model based on deep neural networks (DNNs), particle swarm optimization (PSO), and genetic algorithms (GAs) is proposed to solve this problem. The DNN can effectively simulate any sophisticated equation, and the PSO and GA can optimize the selected DNN and improve the performance of the prediction model. In the present study, analytical solutions to vertical drains in the literature are incorporated into the DNN–PSO and DNN–GA prediction models with three different radial drainage patterns in the smear zone under time-dependent loading. The verification performed with analytical solutions and measurements from three full-scale embankment tests revealed promising applications of the proposed approach.

关键词： vertical drain artificial neural network time-dependent loading deep learning network genetic algorithm particle swarm optimization

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天基信息实时智能服务系统仿真评估研究

江昊,李德仁,沈欣,吴静

《中国工程科学》 2020年第22卷第2期页码 153-160 doi: 10.15302/J-SSCAE-2020.02.019

摘要：

天基信息实时智能服务系统（PNTRC）是多星协同、多网互联的下一代天基信息系统，将广泛应用在卫星通信、导航、遥感等领域。本文针对 PNTRC 建模仿真和效能评估展开研究，分析了系统评估仿真的必要性、需求以及发展趋势，进而支撑PNTRC顶层设计和实施方案论证。针对 PNTRC 动态时变、业务多样、异质异构的特性，对场景可扩展的高效分布式仿真、时空动态分析评估方法、系统体系化建模等关键技术展开详细讨论。基于分布式仿真评估系统，以高分辨率对地遥感业务为例，对比和评估了多个低轨通信星座对遥感业务的传输支持能力。研究结果表明，在遥感业务数据传输过程中，覆盖密集的OneWeb 星座卫星具有更小的网络时延、丢包以及更高的容量和稳定性，但单星容量反而不及覆盖密度较小的“虹云”“鸿雁”星座。本文研究为我国PNTRC可行性论证与工程建设提供了方法和技术手段支撑。

关键词：天基信息实时服务仿真评估低轨通信星座

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陆海空天一体化信息网络发展研究

徐晓帆,王妮炜,高璎园,陆洲,汪春霆,陆军

《中国工程科学》 2021年第23卷第2期页码 39-45 doi: 10.15302/J-SSCAE-2021.02.006

摘要：

陆海空天一体化信息网络具有为陆基、海基、空基、天基等各类用户提供全球随遇接入、信息安全可靠服务的能力，是我国避免受制于人、实现网络强国的重要基础设施之一。立足于我国一体化信息网络的发展，本文以文献调研、专家咨询的研究方式，梳理了陆海空天一体化信息网络的发展需求，开展了国内外典型系统的分析研究，总结了我国在先进陆海空天一体化信息网络方面存在的主要问题及差距，重点提出适合国情的融合网络架构初步设想及相应发展路线建议。研究认为，在推进陆海空天一体化信息网络论证设计和工程实施的过程中，应着重强化网络架构、技术体制、应用服务支撑体系方面的深度融合，兼顾通信、导航、遥感系统的功能融合，推动天基网络技术自主可控和高端产业升级，同步加强相关系统的安全防护能力建设。

关键词：陆海空天一体化信息网络，天基信息系统，网络架构，融合网络，发展路线

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平坦快衰落条件下天线数较多时空时格码的设计

耿嘉,曹秀英,毕光国

《中国工程科学》 2006年第8卷第6期页码 48-54

摘要：

空时格码技术是近年来无线通信领域的一个研究热点，空时格码的设计准则问题一直是该技术的一个难点。在平坦快衰落条件下且天线数目较多时，基于最小平方欧式距离最大化的空时格码设计准则虽然优于经典的距离－积准则，但仍不完善。从平方距离分布与平方距离和方－方和比分布的角度对此进行了改进，得到改进的准则以及性能为目前最优的新码。还对快慢2种衰落条件下码性能差异的原因给出了新的解释，并将改进的码设计准则应用于智贪码的设计。

关键词：空时格码准则平坦快衰落距离分布