Measuring Internet performance for home users can provide useful information for improving networks. Unfortunately, Internet measurements typically require users to install special software, a major impediment to use. To overcome this impediment, we designed and implemented several scripting techniques to predict Internet performance from within the tightly constrained sandbox environment of a Web browser. Our techniques are integrated into a Web site project called “How's My Network” that provides predictions for common Internet activities, with this paper concentrating on the performance of online news, social networks, and online shopping. The contributions of this work include the design, implementation and evaluation of new approaches for predicting Web browser performance.

Web-based services involving dynamic computation of the content are increasingly used on the Web. This computation may not only involve processing, but often involves access to other back-end services typically for database access. These multi-tiered Web-based services have different characteristics than traditional Web content and new models need to be considered not only how to manage them, but also how the DNS mechanism should map clients to the appropriate front-end server. In this work we study the potential of considering back-end service times in the decision of mapping clients to servers. We do so by gathering data from deployed platforms in the Internet today from client locations both scattered around the globe and around the United States. We use these data for the simulation of straightforward policies that account for back-end service time. Our results show that in the best case our simple policies have better performance than using current DNS decisions, while in the worst case they provide comparable performance for a range of performance metrics.

Purpose The purpose of this paper is to take a novel approach to help users better understand and be more aware of what third parties are learning about them as they browse the web. Design/methodology/approach The approach the authors take is to personalize the awareness by using JavaScript embedded in a web page to examine portions of a user's web-browser history in order to ascertain web sites that the user has visited. The authors then personalize information reported to the user about what third-party sites are tracking the user's behavior along with demographic information these sites may be inferring from these visited sites and the user's geographic location. Findings It was found that 63 percent of users agreed with a statement of concern for third parties monitoring activities, about half of the respondents agreed with a concern for knowledge about a user's location and a little more than half agreed to concern about inference of demographic information. It was found that females are more concerned about these issues than males. In terms of possible actions, a majority of users report using an ad blocker tool and even more delete cookies at least some amount of time. Using an opt-out mechanism or removing browser history is done by less than 20 percent of users. Despite expressing more concern for information known by third parties, females are not significantly more likely to take actions that may limit what is leaked to these third parties. A contributor to this discrepancy is that females were much less likely to know their settings for many of the actions, indicating less familiarity with them. Social implications Web privacy is an important social issue so helping users to better understand tracking of their actions, along with what actions can be taken to limit tracking, is important. Originality/value The paper takes an original approach to helping users understand what third parties learn about them and follows up that approach with a survey of user attitudes and actions on this important topic.

As part of a project to develop a user-centered network measurement platform that limits impediments to participation, this work focuses on using the execution of a signed Java applet for home network measurement. We have developed a Java applet tool to understand the capabilities of such a tool for measuring characteristics of a user's network environment from the browser. This paper reports on the capabilities of the tool, the measurement methodology employed, and initial results obtained for a set of residential users employing the tool. Despite the sandbox-type restrictions in Java, the results include information about the configuration of the user's testing machine, wireless connectivity of the testing machine, available upload and download throughput, DNS performance and the number and type of devices on the user's network.

For the last few years we have been studying the diffusion of private information for users as they visit various Web sites triggering data gathering aggregation by third parties. This paper reports on our longitudinal study consisting of multiple snapshots of our examination of such diffusion over four years. We examine the various technical ways by which third-party aggregators acquire data and the depth of user-related information acquired. We study techniques for protecting privacy diffusion as well as limitations of such techniques. We introduce the concept of secondary privacy damage. Our results show increasing aggregation of user-related data by a steadily decreasing number of entities. A handful of companies are able to track users' movement across almost all of the popular Web sites. Virtually all the protection techniques have significant limitations highlighting the seriousness of the problem and the need for alternate solutions.

Various bits of information about users accessing Web sites. some of which are private, have been gathered since the inception of the Web. Increasingly the gathering, aggregation, and processing has been outsourced to third parties. The goal of this work is to examine the effectiveness of specific techniques to limit this diffusion of private information to third parties. We also examine the impact of these privacy protection techniques on the usability and quality of the Web pages returned. Using objective measures for privacy protection and page quality we examine their tradeoffs for different privacy protection techniques applied to a collection of popular Web sites as well as a focused set of sites with significant privacy concerns. We study privacy protection both at a browser and at a proxy.

As a follow up to characterizing traffic deemed as unwanted by Web clients such as advertisements, we examine how information related to individual users is aggregated as a result of browsing seemingly unrelated Web sites. We examine the privacy diffusion on the Internet, hidden transactions, and the potential for a few sites to be able to construct a profile of individual users. We define and generate a privacy footprint allowing us to assess and compare the diffusion of privacy information across a wide variety of sites. We examine the effectiveness of existing and new techniques to reduce this diffusion. Our results show that the size of the privacy footprint is a legitimate cause for concern across the sets of sites that we study.

Web pages include extraneous material that may be viewed as undesirable by a user. Increasingly many Web sites also require users to register to access either all or portions of the site. Such tension between content owners and users has resulted in a "cat and mouse" game between content provided and how users access it.We carried out a measurement-based study to understand the nature of extraneous content and its impact on performance as perceived by users. We characterize how this content is distributed and the effectiveness of blocking mechanisms to stop it as well as countermeasures taken by content owners to negate such mechanisms. We also examine sites that require some form of registration to control access and the attempts made to circumvent it.Results from our study show that extraneous content exists on a majority of popular pages and that a 25-30% reduction in downloaded objects and bytes with corresponding latency reduction can be attained by blocking such content. The top ten advertisement delivering companies delivered 40% of all URLs matched as ads in our study. Both the server name and the remainder of the URL are important in matching a URL as an ad. A majority of popular sites require some form of registration and for such sites users can obtain an account from a shared public database. We discuss future measures and countermeasures on the part of each side.

In this work, we propose a novel methodology that can be used to assess the relative popularity for any Internet application based on the data servers it uses. The basic idea is to infer popularity of data servers by periodically "poking" at local Domain Name servers (LDNSs) that service Domain Name System requests from a set of users running Internet applications and determining if LDNSs have cached resource records for the data servers. This approach allows us to measure the relative percentage of pokes that result in a cache hit as a coarse measure of the relative popularity of a particular data server among the users of a given LDNS. In addition, the time-to-live (TTL) of cached DNS resource records can be used to measure the gaps in time when a resource record for a data server is not cached. The cache gaps can be used to infer request interarrivals for more popular data servers.The methodology can be applied to any Internet application that uses distinguished server names and performs DNS lookups on these names as part of application use. The methodology can be used to collect usage information from any LDNS that accepts DNS queries. As example applications of the methodology, we evaluate the relative popularity of selected Web sites and the relative popularity of different Web servers serving content at a given Web site. We also apply the methodology to servers providing multimedia content, data servers for grid computing, and network game servers. We use data gathered from LDNSs of commercial and educational sites as well as Internet Service Providers serving both commercial and home customers.

In earlier work we proposed a way for a Web server to detect connectivity information about clients accessing it in order to take tailored actions for a client request. This paper describes the design, implementation, and evaluation of such a working system. A Web site has a strong incentive to reduce the `time-to-glass' to retain users who may otherwise lose interest and leave the site. We have performed a measurement study from multiple client sites around the world with various levels of connectivity to the Internet communicating with modified Apache Web servers under our control. The results show that clients can be classified in a correct and stable manner and that user-perceived latency can be reduced via tailored actions. Our measurements show that classification and determination of server actions are done without significant overhead on the Web server. We explore a variety of modified actions ranging from selecting a lower quality version of the resource to altering the manner of content delivery. By studying numerous performance related factors in a single unified framework and examining both individual actions as well as combination of actions, our modified Web server implementation shows the efficacy of various server actions.

The problem of Web cache consistency continues to be an important one. Current Web caches use heuristic-based policies for determining the freshness of cached objects, often forcing content providers to unnecessarily mark their content as uncacheable simply to retain control over it. Server-driven invalidation has been proposed as a mechanism for providing strong cache consistency for Web objects, but it requires servers to maintain per-client state even for infrequently changing objects. We propose an alternative approach to strong cache consistency, called MONARCH, which does not require servers to maintain per-client state. In this work we focus on a new approach for evaluation of MONARCH in comparison with current practice and other cache consistency policies. This approach uses snapshots of content collected from real Web sites as input to a simulator. Results of the evaluation show MONARCH generates little more request traffic than an optimal cache coherency policy.

No abstract available.

This special session presents issues, approaches and experiences related to incorporating Human-Computer Interaction (HCI) into the undergraduate CS curriculum. Since the publication of the ACM SIGCHI Curricula for Human-Computer Interaction in 1992 [1], CS educators have tried various implementations of these guidelines. These implementations have been mainly offered as elective courses or modules within other courses, partly because the CS mainstream has been slow to recognize the importance of user interface design and HCI issues in software development.Today at least 50% of the code written for software applications is specific to the user interface. Average end-user expertise is continually dropping due to the proliferation of inexpensive computers available to the general public. Accordingly, user interface effectiveness has become increasingly important in software development, as the user interface has the power to make or break a software product. Through its emphasis on user-centered design, task analysis, and usability evaluation among other topics, an HCI course addresses more than 1/3 of the guidelines and imperatives of the ACM Code of Ethics [2]. This includes issues related to professional review, evaluations of computer systems, social responsibility and quality of life, and non-discrimination and dignity of end-users.CS educators have begun realizing the importance of incorporating HCI into the educational experience of students. Approximately 40% of the CAC-accredited degree programs include an HCI course at the upper level; however, this course is offered mostly as an elective (37% of degree programs) as opposed to a required course (3% of degree programs) [3]. Also, HCI is included as a core knowledge area in Computing Curricula 2001 [4, 5, 6]; unfortunately, only six hours have been devoted to it, as opposed to, say, 36 hours for architecture.

We categorize the set of clients communicating with a server on the Web based on information that can be determined by the server. The Web server uses the information to direct tailored actions. Users with poor connectivity may choose not to stay at a Web site if it takes a long time to receive a page, even if the Web server at the site is not the bottleneck. Retaining such clients may be of interest to a Web site. Better connected clients can receive enhanced representations of Web pages, such as with higher quality images.We explore a variety of considerations that could be used by a Web server in characterizing a client. Once a client is characterized as poor or rich, the server can deliver altered content, alter how content is delivered, alter policy and caching decisions, or decide when to redirect the client to a mirror site. We also use network-aware client clustering techniques to provide a coarser level of client categorization and use it to categorize subsequent clients from that cluster for which a client-specific categorization is not available.Our results for client characterization and applicable server actions are derived from real, recent, and diverse set of Web server logs. Our experiments demonstrate that a relatively simple characterization policy can classify poor clients such that these clients subsequently make the majority of badly performing requests to a Web server. This policy is also stable in terms of clients staying in the same class for a large portion of the analysis period. Client clustering can significantly help in initially classifying clients for which no previous information about the client is known. We also show that different server actions can be applied to a significant number of request sequences with poor performance.

Typical undergraduate operating systems projects use services provided by an operating system via system calls or develop code in a simulated operating system. With the increasing popularity of operating systems with open source code such as Linux, there are untapped possibilities for operating systems projects to modify real operating system code. We present the hardware and software configuration of an open source laboratory that promises to provide students that use it with a better understanding of operating system internals than is typically gained in a traditional operating systems course. Our preliminary projects and evaluation suggest that thus far the lab has achieved its primary goal in that students that used the lab feel more knowledgeable in operating systems and more confident in their ability to write and modify operating system code.

Article Share on N for the price of 1: bundling web objects for more efficient content delivery Authors: Craig E. Wills Computer Science Dept., Worcester Polytechnic Institute, Worcester, MA Computer Science Dept., Worcester Polytechnic Institute, Worcester, MAView Profile , Mikhail Mikhailov Computer Science Dept., Worcester Polytechnic Institute, Worcester, MA Computer Science Dept., Worcester Polytechnic Institute, Worcester, MAView Profile , Hao Shang Computer Science Dept., Worcester Polytechnic Institute, Worcester, MA Computer Science Dept., Worcester Polytechnic Institute, Worcester, MAView Profile Authors Info & Claims WWW '01: Proceedings of the 10th international conference on World Wide WebMay 2001 Pages 257–265https://doi.org/10.1145/371920.372061Published:01 April 2001Publication History 19citation478DownloadsMetricsTotal Citations19Total Downloads478Last 12 Months3Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

This paper describes our experiences with the Webware, Interfaces and Networking Experimental (WINE) Laboratory. The WINE Lab was created to assist in teaching the topics of computer networks, user interfaces and webware. The goal of the lab is to provide students with the opportunity to complete projects, experiment with relevant techniques and make connections between topics with resources not available in a general purpose Unix-based computing environment. The results from offering courses with the lab show success in meeting these goals. 1 Introduction The paper describes our experiences with the Webware, Interfaces and Networking Experimental Laboratory (WINE Lab) here at Worcester Polytechnic Institute (WPI). This lab was developed to assist in teaching the topics of computer networks, user interfaces and webware. The objective in developing the WINE Lab was to improve these three courses by providing students with the opportunity to complete projects, experiment with relevant...

This work studies the interaction of Web proxy cache coherency and replacement policies using trace-driven simulations. We specifically examine the relative importance of each type of policy in affecting the overall costs, the potential of incorporating coherency issues in cache replacement and the inclusion of additional factors such as frequency of resource use in replacement and coherency policies. The results show that the cache replacement policy in use is the primary cost determinant for relatively small caches, while the cache coherency policy is the determinant for larger caches. Incorporating cache coherency issues in cache replacement policies yields little improvement in overall performance. The use of access frequency in cache replacement, along with temporal locality and size information, results in a simple and better performing policy than found in previously published work. Combining this new replacement policy with the best piggyback-based cache coherency policy results in a 4.5% decrease in costs and 89% reduction in staleness ratio when compared to policy combinations in current use. Preliminary work indicates that cache replacement and coherency policies continue to affect costs in the presence of HTTP protocol enhancements such as persistent connections.

No abstract available.

No abstract available.

A problem in teaching large introductory computer science courses is to overcome the impersonality of the large lecture class and to provide more personal attention to individual students.Our approach as to use peer [earning experiences to instill in students the need to take responsibility for their learning and for ihe learning of those around them.Recent work has shown that educational quality for students and productivity for faculty can be enhanced through use of peer-learning environments where students do not just learn and faculty do not just teach.The novel aspects of our work are to apply group learning in a large introductory computer science class setting and to expect more responsibility on the part of students for their learning.In support of these goals we have introduced the use of upper-level undergraduate students to help facilitate student group interaction.In addition, we have developed software to minimize the administrative overhead of handling many groups and for students to electronically record group learning activities.

One issue in distributed computing systems is how to locate and manage resource information that is inherently distributed within the computing environment. The article investigates the use of a technique called multicasting for location of such distributed information. It presents three different strategies for using the resources contained by a machine to dynamically compute the multicast addresses on which the machine should listen for requests of the information. The central goal of these strategies is to filter out requests for resource information at the network interface of a machine so that a machine only receives a request for information if it contains the resource.>

A service execution mechanism is designed to provide users transparent access to computational services in a distributed environment. The central idea in this approach is that computations available to the user in a distributed system should be treated as services, where a service is a user-level computation that is offered by one or more machines. The identification of a service is separate from its execution for all computations available to the user. This abstraction allows the details of performing a service to be hidden from the user, and allows the user to specify what services he/she would like to use and not be concerned with where or how the services are invoked. The author's experience with a prototype implementation is reviewed. It is concluded that the service mechanism is a small cost in the total time to execute a simple local service, and an insignificant cost for more computation-intensive services. For services that are invoked remotely, additional costs may be incurred for probing during selection, but these costs are negligible in comparison to the costs of invocation.>

General techniques are first examined for managing distributed information and how various evaluation criteria, when applied to the techniques, are affected by the parameters and scale of a problem. Then the use of the techniques and criteria is illustrated for the problems of locating service and server status information, as well as determining the current status of a user in a distributed environment. In each case, the best technique to use for the problem based on its parameters is obtained.>

As a user's computing environment grows from a single time-shared host to a network of specialized and general-purpose machines, the capability for the user to access all of these resources in a consistent and transparent manner becomes desirable. Instead of viewing commands as binary files, we expect the user to view commands as services provided by servers in the network. The user interacts with a personal workstation that locates and executes services on his behalf.