10633849
Assessing differential usage of usenet social accounting meta-data
We describe a usage study of NetscanTech, a system that generates and publishes daily a range of social metrics across three dimensions: newsgroup, author, and thread, for a set of approximately 15,000 technical newsgroups in Usenet. We bring together three interlinked datasets: survey data, usage log data and social accounting data from Usenet participation, to triangulate the relationship between various user roles and differential usage of social metrics in NetscanTech. We found our most frequent users focused on information related to individual authors far more than any other information provided. In contrast, users that visited less frequently focused more on information related to newsgroups and viewing newsgroup metrics. Our results suggest features that designers and developers of online communities may wish to include in their interfaces to support the cultivation of different community roles.
402019
Conversation trees and threaded chats
Chat programs and instant messaging services are increasingly popular among Internet users. However, basic issues with the interfaces and data structures of most forms of chat limit their utility for use in formal interactions (like group meetings) and decision-making tasks. In this paper, we discuss Threaded Text Chat, a program designed to address some of the deficiencies of current chat programs. Standard forms of chat introduce ambiguity into interaction in a number of ways, most profoundly by rupturing connections between turns and replies. Threaded Chat presents a solution to this problem by supporting the basic turn-taking structure of human conversation. While the solution introduces interface design challenges of its own, usability studies show that users' patterns of interaction in Threaded Chat are equally effective, but different (and possibly more efficient) than standard chat programs.
5888435
Visualization components for persistent conversations
An appropriately designed interface to persistent, threaded conversations could reinforce socially beneficial behavior by prominently featuring how frequently and to what degree each user exhibits such behaviors. Based on the data generated by the Netscan data-mining project [9], we have developed a set of tools for illustrating the structure of discussion threads like those found in Usenet newsgroups and the patterns of participation within the discussions. We describe the benefits and challenges of integrating these tools into a multi-faceted dashboard for navigating and reading discussions in social cyberspaces like Usenet and related interaction media. Visualizations of the structure of online discussions have applications for research into the sociology of online groups as well as possible interface designs for their members.
26831752
Incrementally visualising criminal networks
Understanding the information gathered thus far in a criminal investigation is of great importance, particularly in terms of guiding its future course. Since the late 1980's the use of software tools to provide visualisations of this information has become increasingly common. The objective of such tools is to provide, in a readily comprehensible way, the social network of all the people involved. This may include the victims, suspects, witnesses, acquaintances and locations of interest in the investigation such as workplaces or nightclubs. Such diagrammatic representations often provide the focus for discussion among the investigating team and are incrementally added to as new facts are discovered. In this paper we present a brief overview of this important subject area and discuss how such software products could be further enhanced. We also present an example that illustrates the basic principles using a demonstrator we developed.
835724
Database Support for Exploring Criminal Networks
An established method of comprehending the data gathered thus far in a criminal investigation is to incrementally visualize it as a network, such as in the diagram displayed below which is referred to as a link chart, to ascertain if, and how, objects of interest are connected.
7182268
Accelerating scientific applications with the SRC-6 reconfigurable computer: methodologies and analysis
Reconfigurable computing offers the promise of performing computations in hardware to increase performance and efficiency while retaining much of the flexibility of a software solution. Recently, the capacities of reconfigurable computing devices, like field programmable gate arrays, have risen to levels that make it possible to execute 64b floating-point operations. SRC Computers has designed the SRC-6 MAPstation to blend the benefits of commodity processors with the benefits of reconfigurable computing. In this paper, we describe our effort to accelerate the performance of several scientific applications on the SRC-6. We describe our methodology, analysis, and results. Our early evaluation demonstrates that the SRC-6 provides a unique software stack that is applicable to many scientific solutions and our experiments reveal the performance benefits of the system.
7589048
Security considerations when designing a distributed file system using object storage devices
We present the design goals that led us to developing a distributed object-based secure file system, Brave. Brave uses mutually authenticated object storage devices, SCARED, to store file system data. Rather than require a new authentication infrastructure. we show how we use a simple authentication protocol that is bridged into existing security infrastructures, even if there is more than one authentication protocol or domain present. We position our work in the context of some of the current work going on in distributed secure file systems and present our implementation of our file system. We also present some security weaknesses that are shared with other distributed file systems that may not be apparent when designing these systems.
14206506
The role of diverse populations in phylogenetic analysis
The most popular approaches for reconstructing phylogenetic trees attempt to solve NP-hard optimization criteria such as maximum parsimony (MP). Currently, the best-performing heuristic for reconstructing MP trees is Recursive-Iterative DCM3 (Rec-I-DCM3), which uses a single tree (or solution) to guide its way through an exponentially-sized tree space. To improve performance further, we designed Cooperative Rec-I-DCM3, a population-based approach for utilizing a population of Rec-I-DCM3 trees.We compare the performance of Cooperative Rec-I-DCM3 to Rec-I-DCM3 on four large biological datasets. Of particular interest is Cooperative Rec-I-DCM3's selection criteria for maintaining a population of solutions. Our experiments reveal that diverse populations outperform Rec-I-DCM3 in terms of average rates of convergence to best-known MP scores. To achieve greater performance, we designed an elitist population strategy, in which each solution's tree score matches that of the best score found in each generation. The elitist strategy was by far the worst overall performer in our experiments. Hence, being greedy is not always the best approach. Instead, a population of diverse solutions allows our cooperative algorithm to achieve the greatest performance improvements.