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• 1. [Article] Content Aware Request Distribution for High Performance Web Service: A Performance Study

  The World Wide Web is becoming a basic infrastructure for a variety of services, and the increases in audience size and client network bandwidth create service demands that are outpacing server capacity. ...

  Citation × Citation Citation Abstract Copy Title: Content Aware Request Distribution for High Performance Web Service: A Performance Study Author: Jones, Robert M. Year: 2002 The World Wide Web is becoming a basic infrastructure for a variety of services, and the increases in audience size and client network bandwidth create service demands that are outpacing server capacity. Web clusters are one solution to this need for highperformance, highly available web server systems. We are interested in load distribution techniques, specifically Layer-7 algorithms that are content-aware. Layer- 7 algorithms allow distribution control based on the specific content requested, which is advantageous for a system that offers highly heterogenous services. We examine the performance of the Client Aware Policy (CAP) on a Linux/Apache web cluster consisting of a single web switch that directs requests to a pool of dual-processor SMP nodes. We show that the performance advantage of CAP over simple algorithms such as random and round-robin is as high as 29% on our testbed consisting of a mixture of static and dynamic content. Under heavily loaded conditions however, the performance decreases to the level of random distribution. In studying SMP vs. uniprocessor performance using the same number of processors with CAP distribution, we find that SMP dual-processor nodes under moderate workload levels provide equivalent throughput as the same number of CPU’s in a uniprocessor cluster. As workload increases to a heavily loaded state however, the SMP cluster shows reduced throughput compared to a cluster using uniprocessor nodes. We show that the web cluster’s maximum throughput increases linearly with the addition of more nodes to the server pool. We conclude that CAP is advantageous over random or round-robin distribution under certain conditions for highly dynamic workloads, and suggest some future enhancements that may improve its performance. Title: Content Aware Request Distribution for High Performance Web Service: A Performance Study Author: Jones, Robert M. Year: 2002 The World Wide Web is becoming a basic infrastructure for a variety of services, and the increases in audience size and client network bandwidth create service demands that are outpacing server capacity. Web clusters are one solution to this need for highperformance, highly available web server systems. We are interested in load distribution techniques, specifically Layer-7 algorithms that are content-aware. Layer- 7 algorithms allow distribution control based on the specific content requested, which is advantageous for a system that offers highly heterogenous services. We examine the performance of the Client Aware Policy (CAP) on a Linux/Apache web cluster consisting of a single web switch that directs requests to a pool of dual-processor SMP nodes. We show that the performance advantage of CAP over simple algorithms such as random and round-robin is as high as 29% on our testbed consisting of a mixture of static and dynamic content. Under heavily loaded conditions however, the performance decreases to the level of random distribution. In studying SMP vs. uniprocessor performance using the same number of processors with CAP distribution, we find that SMP dual-processor nodes under moderate workload levels provide equivalent throughput as the same number of CPU’s in a uniprocessor cluster. As workload increases to a heavily loaded state however, the SMP cluster shows reduced throughput compared to a cluster using uniprocessor nodes. We show that the web cluster’s maximum throughput increases linearly with the addition of more nodes to the server pool. We conclude that CAP is advantageous over random or round-robin distribution under certain conditions for highly dynamic workloads, and suggest some future enhancements that may improve its performance. Close

• 2. [Article] Using Spammers' Computing Resources for Volunteer Computing

  Spammers are continually looking to circumvent counter-measures seeking to slow them down. An immense amount of time and money is currently devoted to hiding spam, but not enough is devoted to effectively ...

  Citation × Citation Citation Abstract Copy Title: Using Spammers' Computing Resources for Volunteer Computing Author: Bui, Thai Le Quy Year: 2014 Spammers are continually looking to circumvent counter-measures seeking to slow them down. An immense amount of time and money is currently devoted to hiding spam, but not enough is devoted to effectively preventing it. One approach for preventing spam is to force the spammer's machine to solve a computational problem of varying difficulty before granting access. The idea is that suspicious or problematic requests are given difficult problems to solve while legitimate requests are allowed through with minimal computation. Unfortunately, most systems that employ this model waste the computing resources being used, as they are directed towards solving cryptographic problems that provide no societal benefit. While systems such as reCAPTCHA and FoldIt have allowed users to contribute solutions to useful problems interactively, an analogous solution for non-interactive proof-of-work does not exist. Towards this end, this paper describes MetaCAPTCHA and reBOINC, an infrastructure for supporting useful proof-of-work that is integrated into a web spam throttling service. The infrastructure dynamically issues CAPTCHAs and proof-of-work puzzles while ensuring that malicious users solve challenging puzzles. Additionally, it provides a framework that enables the computational resources of spammers to be redirected towards meaningful research. To validate the efficacy of our approach, prototype implementations based on OpenCV and BOINC are described that demonstrate the ability to harvest spammer's resources for beneficial purposes. Title: Using Spammers' Computing Resources for Volunteer Computing Author: Bui, Thai Le Quy Year: 2014 Spammers are continually looking to circumvent counter-measures seeking to slow them down. An immense amount of time and money is currently devoted to hiding spam, but not enough is devoted to effectively preventing it. One approach for preventing spam is to force the spammer's machine to solve a computational problem of varying difficulty before granting access. The idea is that suspicious or problematic requests are given difficult problems to solve while legitimate requests are allowed through with minimal computation. Unfortunately, most systems that employ this model waste the computing resources being used, as they are directed towards solving cryptographic problems that provide no societal benefit. While systems such as reCAPTCHA and FoldIt have allowed users to contribute solutions to useful problems interactively, an analogous solution for non-interactive proof-of-work does not exist. Towards this end, this paper describes MetaCAPTCHA and reBOINC, an infrastructure for supporting useful proof-of-work that is integrated into a web spam throttling service. The infrastructure dynamically issues CAPTCHAs and proof-of-work puzzles while ensuring that malicious users solve challenging puzzles. Additionally, it provides a framework that enables the computational resources of spammers to be redirected towards meaningful research. To validate the efficacy of our approach, prototype implementations based on OpenCV and BOINC are described that demonstrate the ability to harvest spammer's resources for beneficial purposes. Close

• 3. [Article] Intersections of Critical Systems Thinking and Community Based Participatory Research in Developing a Web Site for Autistic Adults

  People with disabilities, including those on the autism spectrum, comprise the world's largest minority and experience significant inequities in Internet use. Existing standards for accessible web sites ...

  Citation × Citation Citation Abstract Copy Title: Intersections of Critical Systems Thinking and Community Based Participatory Research in Developing a Web Site for Autistic Adults Author: Raymaker, Dora Madeline Year: 2015 People with disabilities, including those on the autism spectrum, comprise the world's largest minority and experience significant inequities in Internet use. Existing standards for accessible web sites are necessary but not sufficient without the direct engagement of end users in identifying access needs. Yet little is known about methods for effective engagement, and there are no systematically derived Web accessibility guidelines for autistic end users. Here I explore a hybrid approach to direct engagement using critical systems thinking (CST) and community based participatory research (CBPR) during the co-development of a healthcare-focused web site by the Academic Autism Spectrum Partnership in Research and Education (AASPIRE). I explore these ideas on three levels: theory, practice, and critical self-reflection. On the theory level, I examine the common philosophical and historical roots of CST and CBPR, ways in which they intersect and complement, and propose the hybrid approach exemplified by AASPIRE. On the practice level, I explore our web site development process and evaluate the accessibility, usability, and acceptability of the web site for autistic end users; from that work, comes a set of recommendations for working with people with disabilities in technology development and a set of accessibility guidelines for autistic end users. On the critical self-reflection level, I inquire into my own experiences as an insider-researcher during the web site development. I then synthesize the levels to evaluate whether or not taking a hybrid CST/CBPR approach to web development was effective, as indicated by the team's ability to function as an emancipatory learning organization (an indicator of effective systems thinking on an organizational level), and the overall usability and accessibility of the web site. The result of the synthesis suggests a hybrid CST/CBPR approach was effective. Implications of this work include innovations in CST methods for operationalizing its commitment to human emancipation, potential for drawing a more ideologically-aligned systems thinking literature into the domain of CBPR, a means for individuals wishing to create a more power-balanced learning organization, innovations around including people with disabilities in research and technology development, more accessible web sites for people on the autism spectrum, and a potential small shift of dominant discourse around autism, disability, and the value of insider-researchers over time. Title: Intersections of Critical Systems Thinking and Community Based Participatory Research in Developing a Web Site for Autistic Adults Author: Raymaker, Dora Madeline Year: 2015 People with disabilities, including those on the autism spectrum, comprise the world's largest minority and experience significant inequities in Internet use. Existing standards for accessible web sites are necessary but not sufficient without the direct engagement of end users in identifying access needs. Yet little is known about methods for effective engagement, and there are no systematically derived Web accessibility guidelines for autistic end users. Here I explore a hybrid approach to direct engagement using critical systems thinking (CST) and community based participatory research (CBPR) during the co-development of a healthcare-focused web site by the Academic Autism Spectrum Partnership in Research and Education (AASPIRE). I explore these ideas on three levels: theory, practice, and critical self-reflection. On the theory level, I examine the common philosophical and historical roots of CST and CBPR, ways in which they intersect and complement, and propose the hybrid approach exemplified by AASPIRE. On the practice level, I explore our web site development process and evaluate the accessibility, usability, and acceptability of the web site for autistic end users; from that work, comes a set of recommendations for working with people with disabilities in technology development and a set of accessibility guidelines for autistic end users. On the critical self-reflection level, I inquire into my own experiences as an insider-researcher during the web site development. I then synthesize the levels to evaluate whether or not taking a hybrid CST/CBPR approach to web development was effective, as indicated by the team's ability to function as an emancipatory learning organization (an indicator of effective systems thinking on an organizational level), and the overall usability and accessibility of the web site. The result of the synthesis suggests a hybrid CST/CBPR approach was effective. Implications of this work include innovations in CST methods for operationalizing its commitment to human emancipation, potential for drawing a more ideologically-aligned systems thinking literature into the domain of CBPR, a means for individuals wishing to create a more power-balanced learning organization, innovations around including people with disabilities in research and technology development, more accessible web sites for people on the autism spectrum, and a potential small shift of dominant discourse around autism, disability, and the value of insider-researchers over time. Close

• 4. [Article] InfoFilter: Supporting Quality of Service for Fresh Information Delivery

  With the explosive growth of the Internet and World Wide Web comes a dramatic increase in the number of users that compete for the shared resources of distributed system environments. Most implementations ...

  Citation × Citation Citation Abstract Copy Title: InfoFilter: Supporting Quality of Service for Fresh Information Delivery Author: Liu, Ling, Pu, Calton, Schwan, Karsten, Walpole, Jonathan Year: 2000 With the explosive growth of the Internet and World Wide Web comes a dramatic increase in the number of users that compete for the shared resources of distributed system environments. Most implementations of application servers and distributed search software do not distinguish among requests to different web pages. This has the implication that the behavior of application servers is quite unpredictable. Applications that require timely delivery of fresh information consequently suffer the most in such competitive environments. This paper presents a model of quality of service (QoS) and the design of a QoS-enabled information delivery system that implements such a QoS modeL The goal of this development is two-fold. On one hand, we want to enable users or applications to specify the desired quality of service requ.irements for their requests so that application-aware QoS adaptation is supported throughout the Web query and search processing. On the other hand, we want to enable an application server to customize how it shou.ld respond to external requests by setting priorities among query requests and allocating server resources using adaptive QoS control mechanisms. We introduce the Infopipe approach as the systems support architecture and underlying technology for building a QoS-enabled distributed system for fresh information delivery. Title: InfoFilter: Supporting Quality of Service for Fresh Information Delivery Author: Liu, Ling, Pu, Calton, Schwan, Karsten, Walpole, Jonathan Year: 2000 With the explosive growth of the Internet and World Wide Web comes a dramatic increase in the number of users that compete for the shared resources of distributed system environments. Most implementations of application servers and distributed search software do not distinguish among requests to different web pages. This has the implication that the behavior of application servers is quite unpredictable. Applications that require timely delivery of fresh information consequently suffer the most in such competitive environments. This paper presents a model of quality of service (QoS) and the design of a QoS-enabled information delivery system that implements such a QoS modeL The goal of this development is two-fold. On one hand, we want to enable users or applications to specify the desired quality of service requ.irements for their requests so that application-aware QoS adaptation is supported throughout the Web query and search processing. On the other hand, we want to enable an application server to customize how it shou.ld respond to external requests by setting priorities among query requests and allocating server resources using adaptive QoS control mechanisms. We introduce the Infopipe approach as the systems support architecture and underlying technology for building a QoS-enabled distributed system for fresh information delivery. Close

• 5. [Article] Thumbnail Preserving Encryption for JPEG

  With more and more data being stored in the cloud, securing multimedia data is becoming increasingly important. Use of existing encryption methods with cloud services is possible, but makes many web-based ...

  Citation × Citation Citation Abstract Copy Title: Thumbnail Preserving Encryption for JPEG Author: Wright, Charles V., Feng, Wu-chi Year: 2015 With more and more data being stored in the cloud, securing multimedia data is becoming increasingly important. Use of existing encryption methods with cloud services is possible, but makes many web-based applications difficult or impossible to use. In this paper, we propose a new image encryption scheme specially designed for protecting JPEG images in cloud photo storage services. Our technique allows efficient reconstruction of an accurate low-resolution thumbnail from the ciphertext image, but aims to prevent the extraction of any more detailed information. This will allow efficient storage and retrieval of image data in the cloud but protect its contents from outside hackers or snooping cloud administrators. Experiments of the proposed approach using an online selfie database show that it can achieve a good balance of privacy, utility, image quality, and file size. Title: Thumbnail Preserving Encryption for JPEG Author: Wright, Charles V., Feng, Wu-chi Year: 2015 With more and more data being stored in the cloud, securing multimedia data is becoming increasingly important. Use of existing encryption methods with cloud services is possible, but makes many web-based applications difficult or impossible to use. In this paper, we propose a new image encryption scheme specially designed for protecting JPEG images in cloud photo storage services. Our technique allows efficient reconstruction of an accurate low-resolution thumbnail from the ciphertext image, but aims to prevent the extraction of any more detailed information. This will allow efficient storage and retrieval of image data in the cloud but protect its contents from outside hackers or snooping cloud administrators. Experiments of the proposed approach using an online selfie database show that it can achieve a good balance of privacy, utility, image quality, and file size. Close