Understanding and reducing web delays

Over the years the number of web users has increased dramatically unfortunately leading to the inherent problem of congestion. This can affect each user's surfing experience. This paper investigates download times associated with a web request, identifies where delays occur, and provides guidelines which can be followed by web developers to enable a faster and more efficient download and service for their users. Copyright © 2005 John Wiley & Sons, Ltd.     

Wireless Internet Access Using IS-2000 Third Generation System: A Performance and Capacity Study

The Internet has been growing tremendously in the recent years and applications like web browsing are becoming increasingly popular. In a collective effort to provide seamless access to the Internet, wireless equipment manufacturers and service providers are developing 3G wireless systems that efficiently support current and future Internet applications. In this paper, we evaluate the performance and capacity of a 3G wireless data system based on IS-2000 standard. We consider web browsing as the common application for all users and evaluate the system performance for single and parallel web browsing sessions. We perform this study through a detailed simulation of web traffic model described by distributions of number of objects per page, object size, page request size and page reading time. The simulation includes HTTP and TCP/IP protocols, link level recovery, radio resource management, mobility, channel model and, delays in the Internet and the radio access network. We quantify important system attributes like average page download times and system throughput (Kb/s per carrier per sector). We also evaluate normalized object download time, normalized page download time, penalty in performance due to link errors, link layer buffer sizes needed, channel holding time, average power used and distribution of the power used in the system.     

Fair end‐to‐end window‐based congestion control in time‐varying data communication networks

Communication networks are time varying and, hence, fair sharing of network resources among the users in such a dynamic environment is a challenging task. In this context, a time‐varying network model is designed, and the shortest user's route is found. In the designed network model, an end‐to‐end window‐based congestion control scheme is developed with the help of internal nodes or router, and the end user can get implicit feedback (throughput). This scheme is considered as fair if the allocation of resources among users minimizes overall congestion or backlog in the networks. Window update approach is based on a multi‐class fluid model and is updated dynamically by considering delays (communication, propagation, and queuing) and the backlog of packets in the user's routes. Convergence and stability of the window size are obtained using a Lyapunov function. A comparative study with other window‐based methods is also provided.     

高校门户网站的表格布局技术研究

网页布局的优良是决定高校门户网站是否美观的一个重要因素,合理的布局不仅能够将网页中的文本、图片等内容完美并直观地呈现给高校门户网站浏览者,而且能够合理地安排网页空间,优化网页的显示效果和提高网页的下载速度,从而给用户良好的浏览体验.     

Efficiency of repeated network interactions

In this paper we consider a network with interactions by two users. Each of them repeatedly issues download requests on the network. These requests may be unsuccessful due to congestion or non-congestion-related errors. A user decides when to cancel a request (that is, what his impatience threshold is) and how long to wait before reissuing his request after cancellation of the previous request (that is, what his waiting time will be). This pair of impatience threshold and waiting time is his strategy. If a customer decides not to wait but to reissue his request immediately, that is, he sets his waiting time to zero, then he is said to use a so-called restart strategy. The goal of the user is to maximize the number of successful requests over a given time span.We study optimal strategies for the users in a game-theoretic framework. We find that in case congestion is the only cause of unsuccessful requests then each of the users will be very patient and any waiting time is optimal. Hence, restart strategies are among the optimal strategies. Second, in case non-congestion-related errors may occur, users will also set large impatience times, but now they will set waiting times to zero; in other words: they immediately reissue an unsuccessful download. In this case all optimal strategies are restart strategies. Hence, in both cases restart strategies are among the optimal strategies. Finally, implementing socially optimal strategies instead of individual optimal ones cannot improve the efficiency of the network usage.     

基于点对点WiFi通信实现移动数据流量卸载的架构：预定-发送

Currently cellular networks do not have sufficient capacity to accommodate the exp-onential growth of mobile data requirements. Data can be delivered between mobile terminals through peer-to-peer WiFi com-munications (e.g. WiFi direct), but contacts between mobile terminals are frequently disrupted because of the user mobility. In this paper, we propose a Subscribe-and-Send architecture and an opportunistic forwarding protocol for it called HPRO. Under Sub-scribe-and-Send, a user subscribes contents on the Content Service Provider (CSP) but does not download the subscribed contents. Some users who have these contents deliver them to the subscribers through WiFi opportunistic peer-to-peer communications. Numerical simulations provide a robust evaluation of the forwarding performance and the traffic of-floading performance of Subscribe-and-Send and HPRO.     

A Learning-Based Approach for Web Cache Management

Web caching has been widely used to alleviate Internet traffic congestion in World Wide Web (WWW) services. To reduce download throughput, an effective strategy on web cache management is needed to exploit web usage information in order to make a decision on evicting the document stored in case of cache saturation. This paper presents a so-called Learning Based Replacement algorithm (LBR), a hybrid approach towards an efficient replacement model for web caching by incorporating a machine learning technique (naive Bayes) into the LRU replacement method to improve prediction of possibility that an existing page will be revised by a succeeding request, from access history in a web log. The learned knowledge includes information on which URL objects in cache should be kept or evicted. The learning-based model is acquired to represent the hidden aspect of user request pattern for predicting the re-reference possibility. By a number of experiments, the LBR gains potential improvement of prediction on revisit probability, hit rate and byte hit rate overtraditional methods; LRU, LFU, and GDSF, respectively.     

Culture and consumer responses to web download time: a four-continent study of mono and polychronism

Most e-commerce sites would like to include as much relevant and sales-inducing content on their pages as possible. Unfortunately, resulting download delays may lead to consumer frustration and a negative attitude toward the product or service displayed. But is frustration with download delay a universal problem or is it culture-specific? How should firms view this problem? These are the primary research questions investigated in the current study. An experiment conducted on four continents was selected as an appropriate research method to answer those questions. Country sites were selected for differing cultural senses of time and how this might affect individual responses to download delay. Our sample included the US and Finnish cultures representing monochronic cultures and Egyptian and Peruvian cultures representing polychronic cultures. Consistent with the proposed hypotheses, subjects from polychronic cultures were significantly less concerned with download delays than subjects in monochronic cultures. Similarly, perceived wait times varied significantly between the mono- and polychronic groups. Practical insights derived from this study enable specific suggestions on customization of web page content richness as well as infrastructure requirements based on the cultural identity of the intended e-Consumer. Moreover, results suggest theoretical implications for future research.     

Mitigating server-side congestion in the Internet throughpseudoserving

Server-side congestion arises when a large number of users wish to retrieve files from a server over a short period of time. Under such conditions, users are in a unique position to benefit enormously by sharing retrieved files. Pseudoserving, a new paradigm for Internet access, provides incentives for users to contribute to the speedy dissemination of server files through a contract set by a “superserver”. Under this contract, the superserver grants a user a referral to where a copy of the requested file may be retrieved in exchange for the user's assurance to serve other users for a specified period of time. Simulations that consider only network congestion occurring near the server show that: (1) pseudoserving is effective because it self-scales to handle very high request rates; (2) pseudoserving is feasible because a user who participates as a pseudoserver benefits enormously in return for a relatively small contribution of the user's resources; (3) pseudoserving is robust under realistic user behavior because it can tolerate a large percentage of contract breaches; and (4) pseudoserving can exploit locality to reduce usage of network resources. Experiments performed on a local area network that account for the processing of additional layers of protocols and the finite processing and storage capacities of the server and the clients, corroborate the simulation results. They also demonstrate the benefits of exploiting network locality in reducing download times and network traffic while making referrals to a pseudoserver. Limitations of pseudoserving and potential solutions to them are also discussed     

An Internet and wireless networking‐based water pipes web application for fault reporting

With the advancement of modern technologies such as smart cities, IoT, and e‐governments, people have to participate in their well‐being self‐governing and safe guard their key resources and critical infrastructures. To employ their efforts efficiently, many modern handy applications are created and solutions are proposed. Supported by the Ministry of Water, we designed and developed a free‐of‐charge web application (App.), easy to download from Google play store and operate using simple gadgets. Users can report water and sewage accidents fast and easy and at no cost. By merging Surveying and Geomatics Engineering with Information and Communication Technology (ICT) with Wireless communication, networking technology, and systems, we are able to create a web application to report complaints of accidents directly to the right delegated call centers at the Water Authority using the Internet and a smart mobile phone (simple gadgets). This will automate the complaint process and cancel the old paper work system. Surveying and Geomatics Engineering are concerned with the creation of an accurate GIS to manage the Water Authority data and in the data uploading into Google Maps. The developed computer program (application) works in two ways: first, it connects users (customer or employee) to the water authority electronically, and second, it allows immediate checking about the location of the complaint, momentarily filling using the Authority coordinate system, immediate action delegation (repair) at the water authority, continuous follow up, and confirmation to the user about the case. It performs as well, the needed coordinate transformation to guarantee exact filing and locations. Several software tools and programming languages are used to achieve this work such as ArcGIS, Google earth, Google map, GIS cloud, and Java and C++. As a case study, we present the App. performance for a town “Al‐Fuheis, Jordan” using the Water Authority data for creating the needed Water pipes and Sewage (GIS). Moreover, we presented the performance and the efficiency of the App. even when using Goggle Maps data only without GIS data intervention and it proved to be satisfying as well. As a result. a web App. called “Water Pipes” for the Water Authority is posted on their web to allow users participation in the reporting and the follow up process to better conserve the very scarce water in the country. In addition, it automates the work at the Water Authority from filing to take action and repair electronically in no time.     

Adaptive Delay Optimization of Multicast-Enabled Coded Caching in Device-to-Device Networks

This letter investigates a delay optimization problem in device-to-device(D2D)networks where users have pre-downloaded subfiles following a coded caching rule.Due to acquiring rest subfiles,users may suffer both receiving and transmitting delays.To achieve the delay minimization,we first propose a delay-aware mode-selection strategy to adaptively choose multicast or D2D communications mode to reduce the receiving-caused delay.By matching these transmit modes with distinct subfile sizes,we further formulate a min-max optimization problem to minimize the delivery delay.Finally,numerical results prove that the proposed scheme outperforms existing ones in terms of both receiving and transmitting delays.     

A Two-Time-Scale Design for Edge-Based Detection and Rectification of Uncooperative Flows

Existing Internet protocols rely on cooperative behavior of end users. We present a control-theoretic algorithm to counteract uncooperative users which change their congestion control schemes to gain larger bandwidth. This algorithm rectifies uncooperative users; that is, forces them to comply with their fair share, by adjusting the prices fed back to them. It is to be implemented at the edge of the network (e.g., by ISPs), and can be used with any congestion notification policy deployed by the network. Our design achieves a separation of time-scales between the network congestion feedback loop and the price-adjustment loop, thus recovering the fair allocation of bandwidth upon a fast transient phase     

End-to-end congestion control for the Internet: delays andstability

Under the assumption that queueing delays will eventually become small relative to propagation delays, we derive stability results for a fluid flow model of end-to-end Internet congestion control. The theoretical results of the paper are intended to be decentralized and locally implemented: each end system needs knowledge only of its own round-trip delay. Criteria for local stability and rate of convergence are completely characterized for a single resource, single user system. Stability criteria are also described for networks where all users share the same round-trip delay. Numerical experiments investigate extensions to more general networks. Through simulations, we are able to evaluate the relative importance of queueing delays and propagation delays on network stability. Finally, we suggest how these results may be used to design network resources     

Multimedia traffic characteristics in broadband networks

It is pertinent to develop a set of simple parameters that can best characterize the variability and the statistical correlations of the packet arrival process. These parameters are then used by the network to allocate its resources among the different users in order to avoid congestion and maintain a predefined quality of service (QOS) for each user. The traffic characterization and modeling of the real-time bursty traffic, mainly voice and video traffic sources, using statistical methods are described. It is shown that the variability of the variance of the sum of consecutive packet interarrival times leads to significant queuing delays and therefore is a major cause of congestion in broadband networks     

基于Android平台与Web服务器的课程管理信息系统

基于Android平台搭建了一个客户端/服务器结构下的课程管理信息系统。客户端为智能手机,使用Android Studio开发,服务器利用Tomcat搭建Web容器,用开发工具My Eclipse10对服务器编程,并用My SQL数据库开发环境提供数据层应用。所用到的开发语言有Java和SQL,最终实现了手机客户端添加、修改、删除课程,课程提醒,用户注册、登录功能,以及课程信息通过Http远程上传和下载。Web端具备后台查看已注册用户的功能。本系统能够为学生选修课程和教师管理课程信息提供方便。     

基于AT2042的嵌入式网络视频监控系统的设计与实现

为了实现中小场合对于视频监控设备的低成本和网络化的需求,设计了一种基于ARM-S3C2410、音视频硬件编解码芯片AT2042的嵌入式网络视频监控系统,该监控系统实现了MPEG-4编解码器,能实现本地的海量存储、远程控制以及运动检测的功能。用户通过在个人计算机(PC)端输入网页服务器的因特网协议(IP)地址来访问服务器,下载安装ActiveX控件,远程监控实现需要的控制。     

一种便捷的移动终端应用程序下载方法

针对目前平台提供商提供的下载方式不够灵活,提出一种应用程序下载的便捷方法,使得用户无需进入繁琐的层层嵌套式的软件目录查找可供下载的应用程序,简化了用户操作。对企业用户而言,移动终端所需下载的应用程序往往只有一个,因此可以实现应用程序的傻瓜式下载并安装,可以避免由于客户所厌烦的繁琐的操作方式而导致的客户流失。最后用实验验证了该方法的便捷性。     

中国移动互联网应用服务领域发展研究

近些年移动互联网各领域快速发展.在用户方面,移动用户规模快速增长,2016年移动互联网用户总数达到20亿.在终端方面,2016年,全球移动智能终端总共出货量达到15亿台,同比增长约5％.在应用方面,移动应用规模超过1000万款,累计下载规模超过万亿.与此同时,移动应用产业飞速发展,其不断融入新型能力,在传感、识别等方向均有突破,并快速融入到人们日常生活的方方面面.随着移动应用服务的发展,其同样出现了诸多问题,危害用户合法权益,影响产业健康持续发展.重点阐述当前移动应用领域发展现状,解析其特点与存在问题,并探索保障行业健康持续发展的相关措施.     

ENROUTE: An Entropy Aware Routing Scheme for Information-Centric Networks (ICN)

With the exponential growth of end users and web data, the internet is undergoing the change of paradigm from a user-centric model to a content-centric one, popularly known as information-centric networks (ICN). Current ICN research evolves around three key-issues namely (i) content request searching, (ii) content routing, and (iii) in-network caching scheme to deliver the requested content to the end user. This would improve the user experience to obtain requested content because it lowers the download delay and provides higher throughput. Existing researches have mainly focused on on-path congestion or expected delivery time of a content to determine the optimized path towards custodian. However, it ignores the cumulative effect of the link-state parameters and the state of the cache, and consequently it leads to degrade the delay performance. In order to overcome this shortfall, we consider both the congestion of a link and the state of on-path caches to determine the best possible routes. We introduce a generic term entropy to quantify the effects of link congestion and state of on-path caches. Thereafter, we develop a novel entropy dependent algorithm namely ENROUTE for searching of content request triggered by any user, routing of this content, and caching for the delivery this requested content to the user. The entropy value of an intra-domain node indicates how many popular contents are already cached in the node, which, in turn, signifies the degree of enrichment of that node with the popular contents. On the other hand, the entropy for a link indicates how much the link is congested with the traversal of contents. In order to have reduced delay, we enhance the entropy of caches in nodes, and also use path with low entropy for downloading contents. We evaluate the performance of our proposed ENROUTE algorithm against state-of-the-art schemes for various network parameters and observe an improvement of 29–52% in delay, 12–39% in hit rate, and 4–39% in throughput.