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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] 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