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1.
本文提出了城市道路网络的动态可分配性概念,以衡量对特定城市道路网络实施动态分配研究的有效性。并将这个概念用于面向动态交通分配的城市道路网络子区划分,考虑了道路网络的动态变化特性,不仅在空间上,也在时间上对道路网络进行了分区研究。该研究可为动态交通分配的建模研究提供合理的背景和对象。  相似文献   

2.
   鉴于发明者在创新活动中的“抱团”研发现象,采用GN算法,识别可再生能源行业发明者合作创新网络的社群结构,根据社群内部成员和社群经纪人网络位点的不同,通过相邻期社群动态追踪,划分社群结构动态配置,实证社群配置与社群创新能力间的关系。结果表明:发明者合作创新网络存在明显的社群划分,不同类型的社群动态配置对社群发明者创新影响显著不同。总体为,动态与静态相协调的社群配置优于双动或双静的社群配置,具体为,“动荡”社群创新能力最弱,“纽带”社群创新能力最强,“独立”及“固化”社群介于两者间。以促进发明者创新,政策应该有利于创新网络动态及稳定的折中。  相似文献   

3.
Wideband code division multiple access (WCDMA) is selected as the air interface scheme for 3G wireless networks. This scheme offers a high data rate that makes the wireless networks a suitable environment for real-time packet data services. 3G networks can be used to deliver multimedia traffic with guaranteed quality of service, but faces the scalability challenge in terms of the number of connections that can be setup in the cellular network. The more connections take place in WCDMA based network, the more interference is created, which yields more QoS degradation. To handle this issue, several algorithms that are collectively alleviate the QoS degradation have been developed and implemented. In this paper, we provide a system link simulator that models the WCDMA cellular network with the necessary radio resource management algorithms. The downlink direction has been simulated as it is usually the limiting link in setting up multimedia sessions, and interactive web sessions. The simulation environment provides, through the implementation of new wrap-around technique, a fair source of intra-cell and inter-cell interference, and avoids session disconnections due to the limited simulation area. Then, we suggest an admission control algorithm for admitting immediate and advance radio resource reservation requests. The admission control algorithm decision is based on the amount of interference that the new request will add to the network. The algorithm relies on the radio resource reservation states that stores all admitted immediate and advance sessions.  相似文献   

4.
The business process outsourcing industry has got disrupted, first by the significant shift in value creation activities from the clients to the service providers, and second by pervasive digital penetration, resulting in the emergence of Digital Transformational Outsourcing (DTO). Service providers now play a more significant role, making their capabilities important. In the new context, service providers require a uniquely different set of dynamic capabilities to handle end-to-end business functions on behalf of their clients while delivering digital value propositions.We study 26 of the largest global business process outsourcing providers to conceptualise and identify six dynamic capabilities of service providers salient in the new context, i.e., consultative, orchestration, insights, network management, knowledge access, and standardisation. Interviews conducted with industry experts provided evidence in support of the identified dynamic capabilities. A novel firm capability dataset was created using secondary data, and using fuzzy-set Qualitative Comparative Analysis (fsQCA), we identify configurations for high and low performance and find them to vary by the firm's broad/narrow scope.  相似文献   

5.
In this paper, the problem of finite-horizon H state estimation is investigated for a class of discrete time-varying complex networks with multiplicative noises and random coupling strengths. The network nodes and estimators are connected via a constrained communication network which allows only one node to send measurement data at each transmission instant. The Round-Robin protocol is introduced to determine which node obtains the access to the network at certain transmission instant. The aim of the addressed problem is to design a set of time-varying estimator parameters such that the prescribed H performance is guaranteed over a finite horizon. By using the stochastic analysis approach and completing-the-square method, sufficient conditions are derived for the existence of the desired estimators in terms of the solution to backward recursive Riccati difference equations. Finally, a numerical example is provided to validate the feasibility and effectiveness of the proposed results.  相似文献   

6.
Computer networks are assuming an increasingly important role in the transmission and manipulation of information. The implementation of the Joint Academic Network (JANET) provides for the first time a truly integrated, private academic network linking all UK universities. Based on a set of standard communication protocols, JANET has largely superseded earlier regional networks, and their associated interconnection procedures which were complex and unwieldy. An in-depth survey of six UK universities and two polytechnic institutions was undertaken with the objective of examining the principal issues to emerge in the field of academic networking in Great Britain. The survey also considered the implications of current network developments for new categories of services and users that are likely to emerge (by contrast with existing network traffic which is primarily associated with data processing and computation).  相似文献   

7.
As access to information becomes more intensive in society, a great deal of that information is becoming available through diverse channels. Accordingly, users require effective methods for accessing this information. Conversational agents can act as effective and familiar user interfaces. Although conversational agents can analyze the queries of users based on a static process, they cannot manage expressions that are more complex. In this paper, we propose a system that uses semantic Bayesian networks to infer the intentions of the user based on Bayesian networks and their semantic information. Since conversation often contains ambiguous expressions, the managing of context and uncertainty is necessary to support flexible conversational agents. The proposed method uses mixed-initiative interaction (MII) to obtain missing information and clarify spurious concepts in order to understand the intention of users correctly. We applied this to an information retrieval service for websites to verify the usefulness of the proposed method.  相似文献   

8.
本文提出了一种简单的交通疏导算法,可以动态调整交通网络中的车流量,还可以得到两个或两个以上的交通疏导方案。本算法具有容易理解、形式规范的特点,无论用于教学还是解决实际问题,都有较大的实用价值。  相似文献   

9.
This paper introduces a polynomial operator called the DT-polynomial as a novel approach to network flow problems. The class of networks dealt with is time-varying in the sense that the capacity, cost, and travel-time of each edge may vary in discrete time. The Dt-polynomial is a polynomial in two operators, D (delay) and T (time), which is used for describing the time-varying transmission characteristics. The paper starts with the mathematics involving the DT-polynomials. A new shortest arrival route algorithm is presented, and its computational complexity is found to be favorable in comparison with others such as Dijkstra's method and the potential method derived from Ford-Fulkerson's technique. Furthermore, a dynamic flow problem is formulated and analyzed in terms of DT-polynomials, and a latest-departure earliest-arrival schedule is given. Finally, a modified DT-polynomial is applied to digital filter networks.  相似文献   

10.
《Journal of The Franklin Institute》2021,358(18):10232-10249
In this paper, we investigate the physical-layer security for an Internet of Things (IoT) relaying network employing non-orthogonal multiple access (NOMA) in the context of non-linear energy harvesting. In particular, a power-constrained source transmits its confidential information to a destination via an IoT device, which first decodes the received signal and then forwards the decoded data together with its own information using the NOMA technique to their respective destinations, while an eavesdropper is overhearing this transmission. Considering the scenario that both the power-constrained source and the IoT device are assumed to work under non-linear energy harvesting modes, and are capable of harvesting energy from a power beacon with a time switching protocol, both analytical and asymptotic expressions for secrecy outage probability as well as the analytical expression for the probability of strictly positive secrecy capacity are derived. In addition, those expressions are also verified with Monte-Carlo simulations.  相似文献   

11.
无线传感器网络节点有着严格的能量限制,目前已有的许多路由协议假定了节点知道网络的全局信息或者让节点根据路由表进行路由。这些方式均会使网络产生较多的通信负荷,增大能量开销。结合多源单汇路由的特点,本文提出了几种局部路由算法。该算法中,节点仅根据目标节点与邻居节点的地理位置、剩余能量等信息,决定下一跳节点,最终建立到达目的节点的路径。本文首次引入了带约束后跳发射的思想,并将这种后跳发射与已有的算法相结合得到新的后跳路由算法。计算机仿真实验表明,在有数据融合的网络中,带约束的后跳-为难度路由算法使得网络的生存时间最长,较其余算法增加了网络11%和14%的工作周期数。最后又将局部路由算法进行合理改进,得到最小化平均为难度的算法,应用于无数据融合的网络中,效果很好。  相似文献   

12.
管卫利 《科技通报》2012,28(6):31-33
提出一种新的动态时隙混合类MAC协议——CA-QC协议。CA-QC协议能够在控制时隙内集中消除所有的接入冲突,并提出消费算法来提高实时业务的QoS保障,然后通过队列管理算法来实现整个网络完全分布式运行。仿真结果表明,对于时延敏感的实时业务,CA-QC协议可以提供有效支持,并可在混合业务环境下,在接入时延和接入效率方面呈现出较好性能。  相似文献   

13.
证明在车辆网络中应用网络编码,其广播容量最大化问题是NP难的;提出一种基于最大编码机会的优化调度算法. 该算法结合网络编码与车辆缓存提供的编码机会,有效提高了广播容量. 结果表明,与贪婪算法相比,该算法获得更大网络编码增益,保证了一定的传输公平性.  相似文献   

14.
一种基于演化神经网络的预测算法   总被引:4,自引:0,他引:4  
李英  李武  王浣尘 《预测》2003,22(6):66-69
在神经网络预测方法中,网络结构的确定直接影响到预测结果的精确性。本文引入演化神经网络,利用遗传算法确定神经网络的结构参数,可以减少对预测用户经验的依赖性。通过对不同时间间隔的交通流实测数据的预测,表明本文中提出的预测方法具有较好的预测效果。  相似文献   

15.
全业务运营接入技术分析   总被引:1,自引:0,他引:1  
电信运营商重组完成后,三大运营商都拥有移动网和固定网,并进行全业务运营,全业务运营要求网络可以承载并维护不同带宽、不同QoS等级的业务,在核心网发展趋于成熟的情况下,接入网技术成为全业务运营成败的关键之一。尽管核心网早已采用光传输技术,但接入网目前的网络现状仍是铜缆接入为主。本文主要讨论目前存在的大量铜缆接入网络作为过渡阶段,为了满足全业务运营的需求可以采用哪些接入技术,以及可以铺设光接入网的地区接入技术的选择。  相似文献   

16.
由于无线网路中链路质量的不稳定、信号的广播传输模式和节点之间存在的相互干扰,针对提高无线网状网络性能的信道分配和路由选择将更加复杂。采用多信道成为一种可选的提高网络容量的方法。本文提出了一种基于2.4GHz 802.11无线网状网络的一种固定信道分配方法,采用了多输入多输出技术使得网络中的数据流以流水线的方式进行传输。在这个场景下多条并行的流可以同时被激活,以此来提升UDP和TCP的传输性能。通过对802.11b网络中1、6和11三个相互不重叠的信道的分配,该信道分配算法在空间上实现邻居节点之间的干扰最小化,其中信道1和11被分配给网状网络的主干传输部分,信道6被分配给用户接入网络。文章最后通过NS2仿真实验,并对本文提出的算法进行了分析。实验结果证明网络的平均吞吐率有大幅度提升,且多跳传输的延迟也被降低。  相似文献   

17.
基于动态交通流量的可变车道自适应控制方法   总被引:1,自引:0,他引:1  
为解决目前可变车道多为手动定时控制、感应控制而引起的可变车道利用率不高以及控制精度不高的问题,首先对影响可变车道属性的因素进行分析,然后以实时的交通流量数据为基础,提出了一种基于动态交通流量的可变车道自适应控制方法,实时地改变可变车道的属性,充分利用可变车道,提高信号交叉口的通行能力。PARAMICS仿真结果表明,该方法能够提高可变车道的利用率,减小信号交叉口的交通延误。  相似文献   

18.
User-created automation applets to connect IoT devices and applications have become popular and widely available. Exploring those applets enables us to grasp the patterns of how users are utilizing and maximizing the power of connection by themselves, which can deliver practical implications for IoT service design. This study builds an IoT application network with the data of the IFTTT(if this then that) platform which is the most popular platform for self-automation of IoT services. The trigger-action relationships of the IFTTT applets currently activated are collected and used to construct an IoT application network whose nodes are IoT service channels, and links represent their connections. The constructed IoT network is then embedded by the node2vec technique, an algorithmic framework for representational learning of nodes in networks. Clustering the embedded nodes produces the four clusters of IoT usage patterns: Smart Home, Activity Tracking, Information Digest, and Lifelogging & Sharing. We also predict the IoT application network using node2vec-based link prediction with several machine learning classifiers to identify promising connections between IoT applications. Feasible service scenarios are then generated from predicted links between IoT applications. The findings and the proposed approach can offer IoT service providers practical implications for enhancing user experiences and developing new services.  相似文献   

19.
移动无线自组网络,通过多跳接入Internet,卫星网和第三代移动系统,构成了下一代无线Ad-hoc互联网,实现了异构网络的融合和资源共享。在下一代移动无线网络环境下,带宽和功率受限,存在着各种传输误差。根据这些特性,本文采用基于方向的小波分形的插值算法,提出了一种适用于移动无线Ad-hoc网络的视频传输的服务质量(Quality of Service,简称QOS)控制方法,模拟结果表明,该算法与现存算法(双线性内插)相比,具有更优的性能(信噪比),并能适应网络带宽的动态变化。  相似文献   

20.
在基于802.16j的无线中继网络中,考虑路由和调度的联合优化问题,最小化系统总调度时间. 首先采用线性规划的方法建立路由,进行链路业务速率分配,然后基于平移和交换思想提出一种链路调度算法. 理论分析证明所提算法的性能在最坏情况下,不会超过最优性能的1.5倍. 仿真结果表明,所提算法的平均性能非常接近最优性能.  相似文献   

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