网络口碑对网络销售农产品的作用机理——基于“天猫”某品牌茶叶销售的实证研究

以网络广泛销售的农产品———茶叶为研究对象,在收集并处理网上顾客评论数据的基础上,探究网络口碑对这类农产品线上销售的作用机理。在控制相关内生性因素的前提下,建立农产品网络口碑弹性模型EK,并对面板数据进行分位数回归分析。结果表明,在农产品网络销售中,网络口碑数量、评分及产品价格对农产品的销售都有显著影响。在不同销量分位数下,各变量对销量的影响不同:口碑数量的弹性趋势相对平稳;口碑评分弹性则呈现出不规则的U型趋势;价格的弹性值均为负,整体走势趋于缓慢上升。

海马注射β-淀粉样蛋白对BACE1 mRNA的影响及通络救脑口服液的干预作用

目的:探讨大鼠大脑海马注射β-淀粉样蛋白1-40对BACE1mRNA表达的影响及通络救脑口服液对其的干预作用。方法:采用大脑海马立体定向注射β-淀粉样蛋白1-40诱导Alzheimer's病动物模型后,药物干预4周,第5周应用实时定量PCR法检测BACE1mRNA表达。结果:模型组BACE12-ΔΔCt为4.67±0.52,2-ΔΔCt显著多于假手术组(1.07±0.08,P<0.01),表明模型组BACE1mRNA表达上调;与模型组比较,盐酸多萘哌齐组(1.80±0.23)、通络救脑口服液48mg、24mg、12mg/kg·d分别为2.92±0.22、1.54±0.25和0.54±0.11,2-ΔΔCt显著减少,表明BACE1mRNA表达下调。结论:大脑海马注射β-淀粉样蛋白1-40后大鼠海马组织BACE1mRNA表达水平明显增高,通络救脑口服液可以抑制海马组织BACE1mRNA的表达,从而发挥其抗老年性痴呆的作用。

多相位渠化平交路口设计

具体介绍了多相位渠化路口的设计思路 ,并结合深圳市平交路口的设计作了具体的分析。

Study on Remote Sensing of Water Depths Based on BP Artificial Neural Network

A momentum BP neural network model （MBPNNM） was constructed to retrieve the water depth information for the South Channel of the Yangtze River Estuary using the relationship between the reflectance derived from Landsat 7 satellite data and the water depth information. Results showed that MBPNNM, which exhibited a strong capability of nonlinear mapping, allowed the water depth information in the study area to be retrieved at a relatively high level of accuracy. Affected by the sediment concentration of water in the estuary, MBPNNM enabled the retrieval of water depth of less than 5 meters accurately. However, the accuracy was not ideal for the water depths of more than 10 meters.

A NEW METHOD FOR FINDING THE NATURAL FREQUENCY SET OF A LINEAR TIME-INVARIANT NETWORK

This paper presents a new method for finding the natural frequency set of a linear time invariant network. In the paper deriving and proving of a common equation are described. It is for the first time that in the common equation the natural frequencies of an n th order network are correlated with the n port parameters. The equation is simple and dual in form and clear in its physical meaning. The procedure of finding the solution is simplified and standardized, and it will not cause the loss of roots. The common equation would find wide use and be systematized.

紧紧依靠质量和人才在市场经济中求发展

陕西省秦洋食品饮料有限公司是一九八四年秉城市经济体制改革的东风诞生的.九年来,公司在产值、产量、

Online Internet Traffic Identification Algorithm Based on Multistage Classifier

Internet traffic classification plays an important role in network management. Many approaches have been proposed to clas-sify different categories of Internet traffic. However, these approaches have specific us-age contexts that restrict their ability when they are applied in the current network envi-ronment. For example, the port based ap-proach cannot identify network applications with dynamic ports; the deep packet inspec-tion approach is invalid for encrypted network applications; and the statistical based approach is time-onsuming. In this paper, a novel tech-nique is proposed to classify different catego-ries of network applications. The port based, deep packet inspection based and statistical based approaches are integrated as a multi-stage classifier. The experimental results demonstrate that this approach has high rec-ognition rate which is up to 98% and good performance of real-time for traffic identifica-tion.

High-precision grating sensor demodulation device's network interface based on DM9000A

High-precision fiber Bragg grating se nsor demodulation instrument with wide-range dynamic scanning can effectivel y improve the measuring range of the optical fiber grating sensor.Ethernet com munication module is an extremely important part of the high-precision grating sensor demodulation device.Network interface based on Ethernet control chip D M9000A is used to send and receive the Bragg grating sensing pulse.The network transformer YL18-2050S is used to convert and filter the pulse from network.The transmitting and receiving program of grating demodulation,hardware circuit of Ethernet transmission interface are designed.The experimental results show that the network interface can achieve accurate and real-time transmissi on of the grating sensing information at high speed.

A High-Elasticity Router Architecture with Software Data Plane and Flow Switching Plane Separation

Routers have traditionally been architected as two elements: forwarding plane and control plane through For CES or other protocols. Each forwarding plane aggregates a fixed amount of computing, memory, and network interface resources to forward packets. Unfortunately, the tight coupling of packet-processing tasks with network interfaces has severely restricted service innovation and hardware upgrade. In this context, we explore the insightful prospect of functional separation in forwarding plane to propose a next-generation router architecture, which, if realized, can provide promises both for various packet-processing tasks and for flexible deployment while solving concerns related to the above problems. Thus, we put forward an alternative construction in which functional resources within a forwarding plane are disaggregated. A forwarding plane is instead separated into two planes: software data plane(SDP) and flow switching plane(FSP), and each plane can be viewed as a collection of "building blocks". SDP is responsible for packet-processing tasks without its expansibility restricted with the amount and kinds of network interfaces. FSP is in charge of packet receiving/transmitting tasks and can incrementally add switching elements, such as general switches, or even specialized switches, to provide network interfaces for SDP. Besides, our proposed router architecture uses network fabrics to achievethe best connectivity among building blocks,which can support for network topology reconfiguration within one device.At last,we make an experiment on our platform in terms of bandwidth utilization rate,configuration delay,system throughput and execution time.

Effects of Dimers on Cooperation in the Spatial Prisoner's Dilemma Game

We investigate the evolutionary prisoner＇s dilemma game in structured populations by introducing dimers, which are defined as that two players in each dimer always hold a same strategy. We find that influences of dimets on cooperation depend on the type of dimers and the population structure. For those dimers in which players interact with each other, the cooperation level increases with the number of dimers though the cooperation improvement level depends on the type of network structures. On the other hand, the dimers, in which there are not mutual interactions, will not do any good to the cooperation level in a single community, but interestingly, will improve the cooperation level in a population with two communities. We explore the relationship between dimers and self-interactions and find that the effects of dimers are similar to that of self-interactions. Also, we find that the dimers, which are established over two communities in a multi-community network, act as one type of interaction through which information between communities is communicated by the requirement that two players in a dimer hold a same strategy.

Congestion control for ATM multiplexers using neural networks：multiple sources／single buffer scenario

A new neural network based method for solving the problem of congestion control arising at the user network interface (UNI) of ATM networks is proposed in this paper. Unlike the previous methods where the coding rate for all traffic sources as controller output signals is tuned in a body, the proposed method adjusts the coding rate for only a part of the traffic sources while the remainder sources send the cells in the previous coding rate in case of occurrence of congestion. The controller output signals include the source coding rate and the percentage of the sources that send cells at the corresponding coding rate. The control methods not only minimize the cell loss rate but also guarantee the quality of information (such as voice sources) fed into the multiplexer buffer. Simulations with 150 ADPCM voice sources fed into the multiplexer buffer showed that the proposed methods have advantage over the previous methods in the aspect of the performance indices such as cell loss rate (CLR) and voice quality.

Study on the Reversible DC-DC Converter as Interface between Low and Medium Voltage DC Networks

This paper introduces an isolated reversible DC-DC converter with a particular topology, which benefits from both the NPC （neutral point clamped） structure and the series-parallel connection of converters. The key property of the proposed topology is the output voltage elevation above the blocking capabilities of each switch, without taking to a delicate synchronization of series-connected semiconductors. The converter is composed by two identical cells, each containing a full bridge, a medium frequency transformer and an NPC converter, connected in parallel at the input and in series at the output. The operation principle of each cell, into which a trapezoidal modulation was implemented, is similar to a DAB （dual active bridge）. A new model improves the dynamic performance of the controller. Simulation and experimental results verify the proposed topology, its control and start-up strategy.

The Rise and Fall of Social Networking Sites： A Comparative Study of Cyworld and Facebook

This study examines why some social networking sites （SNSs） stagnate while other SNSs grow by comparing Cyworld with Facebook. Cyworld was one of the most successful SNSs in the world, but its international expansion efforts failed. Facebook＇s open technology has had considerable influence on various sectors of the economy and society and allowed it to become a dominant SNS at the global level, whereas Cyworld has remained a local SNS. Facebook＇s open platform and application programming interface （API） pose a serious challenge to Cyworld＇s walled-garden approach. Cyworld is based on strong ties fostering close relationships, whereas Facebook expands social networks through its open and weak ties and has more network power than Cyworld. Therefore, openness is the main reason behind the rise of Facebook and the fall of Cyworld.

Mozambique Ports in the 16th Century： Trade Routes, Changes, and Knowledge in the Indian Ocean Under Portuguese Rule

Arriving to the east African coast in the 16th century, Portuguese faced an important and well-structured commercial network dominated by Muslim merchants. Operating throughout the Indian Ocean and in articulation with the inland African trade routes by way of the coastal settlements from Bazaruto up to the north of Mozambique, this network bustled luxury goods and basic goods benefiting either from a network of inter-personal relationships and kinship that supported the whole business, or from an ancestral knowledge on the techniques and particular procedures indispensable to navigating in the Indian Ocean. This trade made the prosperity of small southern ports, like Sofala or Mozambique long before the Portuguese arrival. However, this trade was so much dependent on the network＇s capacity of organisation and the supply demand relation of the goods involved, as well as on other factors such as the political stability of the African kingdoms, the environmental changes that shaped flows and trade routes or the actual knowledge of the region and of the different forms of organization of local communities. By focusing in the ports of Sofala and Mozambique and the information provided by the Portuguese documents we intend to analyse its evolution during the 16th century in order to understand its role in the Indian Ocean commercial network under Portuguese rule.

The Fatherhood Premium： Mirage or Reality？ How Do Occupational Characteristics Matter

A differential fatherhood premium exists among selected groups of fathers of various socio-economic backgrounds. Besides marital status, residential arrangement, biological paternity, and other demographic dimensions, the mechanisms associated with fathers＇ structural characteristics of work that produce divergent labor market outcomes are less well understood. The authors leveraged the cases of productivity and specialization, family and responsibility, and compensating differentials and examined the impacts of work context and occupational characteristics on the pay gap between fathers and non-fathers Based on joint data from the 1997-2015 National Longitudinal Survey of Youth （NLSY97） and Occupational Information Network （O＇NET） （n -- 37,138）, the authors used fixed-effects models to estimate the associations between job features and the fatherhood premium. The regression results showed that occupations entailing competition and requiring on-the-job training are associated with more wage bonus; occupations offering inflexible schedule are associated with less wage gain These work-related characteristics further emphasize fathers＇ work structure and context, human capital accumulation, and work-family conflict. Overall, these findings are consistent with the theoretical perspectives of productivity and specialization and compensating differentials, adding new evidences to the structural explanations of the fatherhood premium.

Comprehensively Context-Aware Approach to Guaranteeing Multimedia Conferencing Services

Service-Oriented Communication(SOC)is a key research issue to enable media communications using the Service-Oriented Architecture(SOA).Motivated by the necessity to guarantee the service quality of our webbased multimedia conferencing system,we present a Comprehensively Context-Aware(CoCA)approach in this paper.One major problem in the existing end-to-end Quality of Service(QoS)management solutions is that they analyse and exploit the relationships between the QoS metrics and corresponding contexts in an isolated manner.In this paper,we propose a novel approach to leveraging such relationships in a comprehensive manner based on Bayesian networks and the fuzzy set theory.This approach includes three phases:1)information feedback and training,2)QoS-to-context mapping,and3)optimal context adaption.We implement the proposed CoCA in the real multimedia conferencing system and compare its performance with the existing bandwidth aware and playback buffer aware schemes.Experimental results show that the proposed CoCA outperforms the competing approaches in improving the average video Peak Signal-to-Noise Ratio(PSNR).It also exhibits good performance in preventing the playback buffer starvation.

SWN: An SDN Based Framework for Carrier Grade WiFi Networks

With the rapid growth of mobile data traffic and vast traffic offloaded from cellular network, Wi-Fi has been considered as an essential component to cope with the tremendous growth of mobile data traffic. Although operators have deployed a lot of carrier grade Wi-Fi networks, but there are still a multitude of arrears for nowadays Wi-Fi networks, such as supporting seamless handover between APs, automatic network access and unified authentication, etc. In this paper, we propose an SDN based carrier grade Wi-Fi network framework, namely SWN. The key conceptual contribution of SWN is a principled refactoring of Wi-Fi networks into control and data planes. The control plane has a centralized global view of the whole network, can perceive the underlying network state by network situation awareness(NAS) technique, and bundles the perceived information and network management operations into northbound Application Programming Interface(API) for upper applications. In the data plane, we construct software access point(SAP) to abstract the connection between user equipment(UE) and access point(AP). Network operators can design network applications by utilizing these APIs and the SAP abstraction to configure and manage the whole network, which makes carrier grade Wi-Fi networks more flexible, user-friendly, and scalable.

EEG classification based on probabilistic neural network with supervised learning in brain computer interface

Aiming at the topic of electroencephalogram （EEG） pattern recognition in brain computer interface （BCI）, a classification method based on probabilistic neural network （PNN） with supervised learning is presented in this paper. It applies the recognition rate of training samples to the learning progress of network parameters. The learning vector quantization is employed to group training samples and the Genetic algorithm （GA） is used for training the network＇ s smoothing parameters and hidden central vector for detemlining hidden neurons. Utilizing the standard dataset I （a） of BCI Competition 2003 and comparing with other classification methods, the experiment results show that the best performance of pattern recognition Js got in this way, and the classification accuracy can reach to 93.8%, which improves over 5% compared with the best result （88.7 % ） of the competition. This technology provides an effective way to EEG classification in practical system of BCI.

Node of International Flows or the Other Face of El Eulma

El Eulma has become an important node of transnational informal trade. It maintains strong relationships with international market places since the period where the ＂Trabendo＂ have seen a wide development in Algeria. On the national and regional level, the city of El Eulma is the main element of the network of informal merchant areas known by ＂Douba＇l＂ markets. The most important areas are located in the central and eastern of Algeria. This dual membership was conferred to it because of the strong presence of import companies and the existence of discrete and dynamic networks well-organized, formed of false importers, This article focuses on commercial trajectories, the forms of networks and their developments and tries to know the logic. From these trajectories, how the merchant places could be formed in Algeria, as was the case for El Eulma.

ARROW-WTCP:A fast transport protocol based on explicit congestion notification over wired/wireless networks

An explicit congestion notification (ECN)-based distributed transport protocol,ARROW-WTCP (AcceleRate tRansmission towards Optimal Window size TCP for Wireless network),was proposed.The ARROW-WTCP enables feasible deployment of ARROW-TCP from wired to wireless networks by providing a joint design of source and router algorithms.The protocol obtains the actual capacity of the wireless channel by calculating the queue variation in base station (BS) and adjusts the congestion window by using the feedback from its bottleneck link.The simulation results show that the ARROW-WTCP achieves strong stability,max-min fairness in dynamic networks,fast convergence to efficiency without introducing much excess traffic,and almost full link utilization in the steady state.It outperforms the XCP-B (eXplicit Control Protocol Blind),the wireless version of XCP,in terms of stability,fairness,convergence and utilization in wireless networks.