Design for very large-scale conversations

Thesis (Ph.D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2000.Includes bibliographical references (leaves 184-200).On the Internet there are now very large-scale conversations (VLSCs) in which hundreds, even thousands, of people exchange messages across international borders in daily, many-to-many communications. It is my thesis that VLSC is an emergent communication medium that engenders new social and linguistic connections between people. VLSC poses fundamental challenges to the analytic tools and descriptive methodologies of linguistics and sociology previously developed to understand conversations of a much smaller scale. Consequently, the challenge for software design is this: How can the tools of social science be appropriated and improved upon to create better interfaces for participants and interested observers to understand and critically reflect upon conversation? This dissertation accomplishes two pieces of work. Firstly, the design, implementation, and demonstration of a proof-of-concept, VLSC interface is presented. The Conversation Map system provides a means to explore and question the social and linguistic structure of very large-scale conversations (e.g., Usenet newsgroups). Secondly, the thinking that went into the design of the Conversation Map system is generalized and articulated as an aesthetics, ethics, and epistemology of design for VLSC. The goal of the second, theoretical portion of the thesis is to provide a means to describe the emergent phenomenon of VLSC and a vocabulary for critiquing software designed for VLSC and computer-mediated conversation in general.Warren Sack.Ph.D

Actor-role analysis : ideology, point of view, and the news

Thesis (M.S.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1994.Includes bibliographical references (leaves 80-85).by Warren Sack.M.S

A Methodological Framework for Socio-Cognitive Analyses of Collaborative Design of Open Source Software

Open Source Software (OSS) development challenges traditional software engineering practices. In particular, OSS projects are managed by a large number of volunteers, working freely on the tasks they choose to undertake. OSS projects also rarely rely on explicit system-level design, or on project plans or schedules. Moreover, OSS developers work in arbitrary locations and collaborate almost exclusively over the Internet, using simple tools such as email and software code tracking databases (e.g. CVS). All the characteristics above make OSS development akin to weaving a tapestry of heterogeneous components. The OSS design process relies on various types of actors: people with prescribed roles, but also elements coming from a variety of information spaces (such as email and software code). The objective of our research is to understand the specific hybrid weaving accomplished by the actors of this distributed, collective design process. This, in turn, challenges traditional methodologies used to understand distributed software engineering: OSS development is simply too "fibrous" to lend itself well to analysis under a single methodological lens. In this paper, we describe the methodological framework we articulated to analyze collaborative design in the Open Source world. Our framework focuses on the links between the heterogeneous components of a project's hybrid network. We combine ethnography, text mining, and socio-technical network analysis and visualization to understand OSS development in its totality. This way, we are able to simultaneously consider the social, technical, and cognitive aspects of OSS development. We describe our methodology in detail, and discuss its implications for future research on distributed collective practices

Thematic Coherence and Quotation Practices in OSS Design-Oriented Online Discussions

http://portal.acm.org/citation.cfm?id=1099237&coll=Portal&dl=GUIDE&CFID=62246420&CFTOKEN=99105023This paper presents an analysis of online discussions in Open Source Software (OSS) design. The objective of our work is to understand and model the dynamics of OSS design that take place in mailing list exchanges. We show how quotation practices can be used to locate design relevant data in discussion archives. OSS developers use quotation as a mechanism to maintain the discursive context. To retrace thematic coherence in the online discussions of a major OSS project, Python, we follow how messages are linked through quotation practices. We compare our quotation-based analysis with a more conventional analysis: a thread-based of the reply-to links between messages. The advantages of a quotation-based analysis over a thread-based analysis are outlined. Our analysis reveals also the links between the social structure and elements in the discussion space and how it shapes influence in the design process

A study of online discussions in an Open-Source Software Community: Reconstructing thematic coherence and argumentation from quotation practices

http://www.springer.com/sgw/cda/frontpage/0,,1-40393-22-46608953-detailsPage%253Dppmmedia%257Ctoc%257Ctoc,00.htmlThis paper presents an analysis of online discussions in Open Source Software (OSS) design. The objective of our work is twofold. First, our research aims to understand and model the dynamics of OSS design that take place in mailing list exchanges. Second, our more long term objective is to develop tools to assist OSS developers to extract and reconstruct design relevant information from previous discussions. We show how quotation practices can be used to locate design relevant data in discussion archives. OSS developers use quotation as a mechanism to maintain the discursive context. To retrace thematic coherence in the online discussions of a major OSS project, Python, we follow how messages are linked through quotation practices. We compare our quotation-based analysis with a more conventional, thread-based analysis of the (reply-to) links between messages. The advantages of a quotation-based analysis over a thread-based analysis are outlined. Our approach provides a means to analyze argumentation and design rationales and promises a novel means to discover design relevant information in the archives of online discussions. Our analysis reveals also the links between the social structure and elements in the discussion space and how it shapes influence in the design process

Do mycorrhizal network benefits to survival and growth of interior Douglas-fir seedlings increase with soil moisture stress?

Facilitation of tree establishment by ectomycorrhizal (EM) networks (MNs) may become increasingly important as drought stress increases with climate change in some forested regions of North America. The objective of this study was to determine (1) whether temperature, CO2 concentration ([CO2]), soil moisture, and MNs interact to affect plant establishment success, such that MNs facilitate establishment when plants are the most water stressed, and (2) whether transfer of C and water between plants through MNs plays a role in this. We established interior Douglas-fir (Pseudotsuga menziesiivar.glauca) seedlings in root boxes with and without the potential to form MNs with nearby conspecific seedlings that had consistent access to water via their taproots. We varied temperature, [CO2], and soil moisture in growth chambers. Douglas-fir seedling survival increased when the potential existed to form an MN. Growth increased with MN potential under the driest soil conditions, but decreased with temperature at 800 ppm [CO2]. Transfer of 13C to receiver seedlings was unaffected by potential to form an MN with donor seedlings, but deuterated water (D2O) transfer increased with MN potential under ambient [CO2]. Chlorophyll fluorescence was reduced when seedlings had the potential to form an MN under high [CO2] and cool temperatures. We conclude that Douglas-fir seedling establishment in laboratory conditions is facilitated by MN potential where Douglas-fir seedlings have consistent access to water. Moreover, this facilitation appears to increase as water stress potential increases and water transfer via networks may play a role in this. These results suggest that conservation of MN potential may be important to forest regeneration where drought stress increases with climate change

Time Course of the Involvement of the Right Anterior Superior Temporal Gyrus and the Right Fronto-Parietal Operculum in Emotional Prosody Perception

In verbal communication, not only the meaning of the words convey information, but also the tone of voice (prosody) conveys crucial information about the emotional state and intentions of others. In various studies right frontal and right temporal regions have been found to play a role in emotional prosody perception. Here, we used triple-pulse repetitive transcranial magnetic stimulation (rTMS) to shed light on the precise time course of involvement of the right anterior superior temporal gyrus and the right fronto-parietal operculum. We hypothesized that information would be processed in the right anterior superior temporal gyrus before being processed in the right fronto-parietal operculum. Right-handed healthy subjects performed an emotional prosody task. During listening to each sentence a triplet of TMS pulses was applied to one of the regions at one of six time points (400–1900 ms). Results showed a significant main effect of Time for right anterior superior temporal gyrus and right fronto-parietal operculum. The largest interference was observed half-way through the sentence. This effect was stronger for withdrawal emotions than for the approach emotion. A further experiment with the inclusion of an active control condition, TMS over the EEG site POz (midline parietal-occipital junction), revealed stronger effects at the fronto-parietal operculum and anterior superior temporal gyrus relative to the active control condition. No evidence was found for sequential processing of emotional prosodic information from right anterior superior temporal gyrus to the right fronto-parietal operculum, but the results revealed more parallel processing. Our results suggest that both right fronto-parietal operculum and right anterior superior temporal gyrus are critical for emotional prosody perception at a relatively late time period after sentence onset. This may reflect that emotional cues can still be ambiguous at the beginning of sentences, but become more apparent half-way through the sentence

Response to Comment on “Plant diversity increases with the strength of negative density dependence at the global scale”

Hülsmann and Hartig suggest that ecological mechanisms other than specialized natural enemies or intraspecific competition contribute to our estimates of conspecific negative density dependence (CNDD). To address their concern, we show that our results are not the result of a methodological artifact and present a null-model analysis that demonstrates that our original findings—(i) stronger CNDD at tropical relative to temperate latitudes and (ii) a latitudinal shift in the relationship between CNDD and species abundance—persist even after controlling for other processes that might influence spatial relationships between adults and recruits

Electrochemical measurements and thermodynamic calculations of redox equilibria in pallasite meteorites: Implications for the eucrite parent body

The intrinsic oxygen fugacity (IOF) of olivine separates from the Salta, Springwater, and Eagle Station pallasites was measured between 850 and 1150[deg]C using oxygen-specific solid zirconia electrolytes at 105 Pa. The experimental apparatus consisted of a double-opposed electrolyte configuration with a CO-CO2 gas-mix bridging atmosphere. Four initial IOF measurements on Salta olivines revealed the effects of grain size and cell memory on experimental results; experiments with an IW cell memory and fine grain size (log fO2), contains Fa12.5 and Fe90.5Ni9.0; Springwater, of intermediate redox state (~IW), contains Fa18.0 and Fe87.5Ni12.1; Eagle Station, the most oxidized sample (IW + 0.5 logfO2), contains Fa20.5 and Fe85.0Ni14.6. Electron microbeam characterization of the starting materials and run products from these experiments have shown that olivine is the only phase present. Thermodynamic calculations of redox equilibria involving equilibrium pallasite assemblages are in good agreement with our experimental results and provide a lower limit to pallasite redox stability; others involving disequilibrium assemblages, suggest that pallasites experienced localized, late-stage oxidation and reduction effects. Consideration of the redox buffer metal-olivine-orthopyroxene utilizing calculated Eucrite Parent Body (EPB) mantle phase compositions indicates that small redox gradients may have existed in the EPB. Such gradients may have produced strong compositional variation within the EPB. In addition, there is apparently significant redox heterogeneity in the source area of Eagle Station Trio (EST) pallasites and Bocaiuva iron meteorites.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28556/1/0000358.pd