Jim Challenger's research while affiliated with IBM and other places

Publications (18)

Article
Full-text available
This article presents a publishing system for efficiently creating dynamic Web content. Complex Web pages are constructed from simpler fragments. Fragments may recursively embed other fragments. Relationships between Web pages and fragments are represented by object dependence graphs. We present algorithms for efficiently detecting and updating Web...
Conference Paper
To support complex, rapidly changing, high-volume Web sites many components contribute to keeping the content current. Monitoring the workflow through all these components is a challenging task. This paper describes a system in which monitoring objects created by the various heterogeneous, distributed components are distributed to any application c...
Article
Efficient disk storage is a crucial component for many applications. The commonly used method of storing data on disk using file systems or databases incurs significant overhead which can be a problem for applications which need to frequently access and update a large number of objects. This paper presents efficient algorithms for managing persiste...
Article
Full-text available
Efficient disk storage is a crucial component for many applications. The commonly used method of storing data on disk using file systems or databases incurs significant overhead which can be a problem for applications which need to frequently access and update a large number of objects. This paper presents efficient algorithms for managing persiste...
Chapter
Full-text available
This paper describes techniques for improving performance at Web sites which receive significant traffic. Poor performance can be caused by dynamic data, insufficient network bandwidth, and poor Web page design. Dynamic data overheads can often be reduced by caching dynamic pages and using fast interfaces to invoke server programs. Web server accel...
Article
Full-text available
This article presents techniques for designing Web sites that need to handle large request volumes and provide high availability. The authors present new techniques they developed for keeping cached dynamic data current and synchronizing caches with underlying databases. Many of these techniques were deployed at the official Web site for the 1998 O...
Conference Paper
Full-text available
This paper presents a publishing system for efficiently creating dynamic Web content. Complex Web pages are constructed from simpler fragments. Fragments may recursively embed other fragments. Relationships between Web pages and fragments are represented by object dependence graphs. We present algorithms for efficiently detecting and updating Web p...
Article
Full-text available
Dynamic Web pages can seriously reduce the performance of Web servers. One technique for improving performance is to cache dynamic Web pages. We have developed the Dynamic Web cache which is particularly well-suited for dynamic pages. Our cache has improved performance significantly at several commercial Web sites. This paper analyzes the design an...
Article
Full-text available
This paper presents a publishing system for efficiently creating dynamic Web content. Complex Web pages are constructed from simpler fragments. Fragments may recursively embed other fragments. Relationships between Web pages and fragments are represented by object dependence graphs. We present algorithms for efficiently detecting and updating Web p...
Conference Paper
Full-text available
This paper presents a new approach for consistently caching dynamic Web data in order to improve performance. Our algorithm, which we call data update propagation (DUP), maintains data dependence information between cached objects and the underlying data which affect their values in a graph. When the system becomes aware of a change to underlying d...
Article
Full-text available
This paper presents a method for precisely specifying data dependencies between cached objects and underlying data which are constantly changing and affect the values of cached objects. Our algorithm, which we call Data Update Propagation (DUP), can be generalized to hierarchies of dependencies where an object has a data dependence on other entitie...
Conference Paper
This paper describes the system and key techniques used for achieving performance and high availability at the official Web site for the 1998 Olympic Winter Games which was one of the most popular Web sites for the duration of the Olympic Games. The Web site utilized thirteen SP2 systems scattered around the globe containing a total of 143 processo...
Article
Full-text available
: This paper describes the system and key techniques used for achieving performance and high availability at the official Web site for the 1998 Olympic Winter Games which was one of the most popular Web sites for the duration of the Olympic Games. The Web site utilized thirteen SP2 systems scattered around the globe containing a total of 143 proces...
Article
A fundamental trend for servers in network-centric computing environments is to evolve from traditional database and transaction servers to information distribution and handling systems. In addition to documents written in the HyperText Markup Language (HTML), data stored in other forms can be retrieved through the Common Gateway Interface (CGI). A...
Conference Paper
Full-text available
A fundamental trend for servers in network-centric computing environments is to evolve from traditional database and transaction servers to information distribution arid handling systems. In addition to documents written in the Hyper Text Markup Language (HTML), data stored in other forms can be retrieved through the Common Gateway interface (CCI)....

Citations

... A key problem with caching dynamic pages is determining what pages should be cached and when a cached page has become obsolete. Our cache provides API's which allow an application program to explicitly add, delete, and update cached objects [4]. Explicit management of the cache is essential for optimal performance and consistency. ...
... Franklin incorporated research from IBM that was developed for the events infrastructure, including the Olympic games web sites. This technology, called Trigger Monitor [2], maintained an object-dependency graph of information fragments within an HTML web site. When a fragment of information changed, all the pages that depended on that fragment were automatically and efficiently updated. ...
... Using a web server to implement an information retrieval system does not dramatically affect the types of algorithms that might be used. Some work is being done to apply web server performance improvements to the development of distributed information retrieval systems [22]. In those cases, the use of pre-started processes, or cliettes, avoids the start-up costs of starting processes from a typical common gateway interface (CGI). ...
... (1) servidores web e (2) jogos interativos multi-usuários. A escalabilidade de servidores web e discutida em vários trabalhos [9,16,15], assim como o impacto do sistema operacional na aceleração de seu desempenho [52,62,61,19,44,18,54]. ...
... es were designed to terminate right after serving their first HTTP request. Similarly, [4] proposes persistent database connections for server processes to the content database. Performance depends heavily on the middleware's implementation. ...
... For example, network traffic can be distributed based on header information (e.g., IP address or TCP ports) or payload information (e.g., signatures). The balanced distribution of data is not fully reliable due to the heterogeneous nature of the security event data [66,67]. For example, if network traffic is distributed based on IP range, one range may contain more number of packets with large size, which may exhaust one node. ...
... The nodes CE1, CE2 and CE3 correspond to the three root elements of the web pages. If we consider the connected subgraphs using these root elements as starting points, we obtain the content units of the three web pages: The use of this type of representation for the model of content units of web pages was suggested in [6] and they called it as Object Dependence Graph (ODG). Several research studies have used this type of models to represent the web pages or to solve their problematic [7]. ...
... Such a balancing reviews the request itself to decide on the route. In [11] and [12], the load balancing in the websites having high access rate in reality has been addressed. In [13] and [14], client-side algorithms for assign the requests to a server have been provided. ...
... As such, the discussion of works strictly related to clustering algorithms will be restricted to the relevant references that are present in the system description. It is important to discuss some of what has been done in the context of dynamic content web applications [3] [4] [5] [6] [7] [8], so as to better appreciate the contribution of the current work. A rather thorough study and comparison of load balancing and scheduling strategies, for the type of applications identified above, can be seen in the work of Amza et al. [9] . ...
... This is because the result of this phase determines the result of the knowledge discovery phase. The methods used according to literature are explained as follows; [27] used Data Update Propagation (DUP) for web content extraction, [28] used Association Rule for web content extraction but did not cover many Hoover websites. [29]used Object Dependence Graphs (ODG) for efficient web content extraction. ...