59732955
What video can and can't do for collaboration: a case study
6543572
Findings from Observational Studies of Collaborative Work
Abstract The work activity of small groups of three to four people was videotaped and analysed in order to understand collaborative work and to guide the development of tools to support it. The analysis focused on the group's shared drawing activity—their listing, drawing, gesturing and talking around a shared drawing surface. This analysis identified specific features of collaborative work activity that raise design implications for collaborative technology: (1) collaborators use hand gestures to uniquely communicate significant information; (2) the process of creating and using drawings conveys much information not contained in the resulting drawings; (3) the drawing space is an important resource for the group in mediating their collaboration; (4) there is a fluent mix of activity in the drawing space; and (5) the spatial orientation among the collaborators and the drawing space has a role in structuring their activity. These observations are illustrated with examples from the video data, and the design implications they raise are discussed.
43821577
When Can I Expect an Email Response? A Study of Rhythms in Email Usage
A study of email responsiveness was conducted to understand how the timing of email responses conveys important information. Interviews and observations explored users' perceptions of how they responded to email and formed expectations of others' responses to them. We identified ways in which users maintain and cultivate a responsiveness image for projecting expectations about their email response. We also discuss other contextual cues people use to discover email responsiveness, which include using other tools such as the calendar and phone, accounting for the amount of work time overlap available, and establishing a pacing between email correspondents. These cues help users develop a sense of when to expect a response and when breakdown has occurred, requiring further action.
18533540
Beyond Instant Messaging
The recent rise in popularity of IM (instant messaging) has driven the developmentof platforms and the emergence of standards to support IM. Especially as theuse of IM has migrated from online socializing at home to business settings,there is a need to provide robust platforms with the interfaces that businesscustomers use to integrate with other work applications. Yet, in the rush todevelop a mature IM infrastructure, it is also important to recognize that IMfeatures and uses are still evolving. For example, popular press stories1 haveraised the concern that IM interactions may be too distracting in the workplace.This concern suggests that we still need to fine-tune the interface design forIM so the benefits of quick, lightweight communication can be gained withoutcreating a distracting burden for users. How can the industry meet the demandfor robust platforms and standards for IM without locking out innovation anddevelopment?
1186186
Piazza: a desktop environment supporting impromptu and planned interactions
Much of the support for communication across distributed communities has focused on meetings and intentional contact. However, most interactions within co-located groups occur when people happen to run into each other. Such unintended interactions should also be supported among distributed communities. We conducted a study of the communication patterns of a large, distributed organization and found that people tend to disseminate information using formal techniques, even though people usually receive information informally. We then designed a system called Piazza that is intended to support the range of communication styles evident in large communities, paying particular attention to adchessing the problems revealed in our study. Piazza allows people to be aware of others who are doing similar tasks when they are using their computers, the~by enabling unintended interactions. It also supports intentiomd contacts and planned meetings. We discuss issues for analysis in an upcoming use study.
12875596
Exploring patterns of social commonality among file directories at work
We studied files stored by members of a work organization for patterns of social commonality. Discovering identical or similar documents, applications, developer libraries, or other files may suggest shared interests or experience among users. Examining actual file data revealed a number of individual and aggregate practices around file storage. For example, pairs of users typically have many (over 13,000) files in common. A prototype called LiveWire exploits this commonality to make file backup and restore more efficient for a work organization. We removed commonly shared files and focused on specific filetypes that represent user activity to find more meaningful files in common. The Consolidarity project explores how patterns of file commonality could encourage social networking in an organizational context. Mechanisms for addressing the privacy concerns raised by this approach are discussed.
444470
Handling uncertainties in workflow applications
Workflow techniques are currently seen as the key techniques to improve the effectiveness and productivity of business processes. Most workflow models take a static view toward workflow applications. The static view requires that all the components are known in advance and the structural information alone can uniquely determine an execution path. Some applications may not have either or both of these properties. In these applications, uncertainty exists. In this paper, we study the issues related to uncertainties. We characterize uncertainties into three categories, domain uncertainty, structural uncertainty and implementation uncertainty, and discuss the impact they have on workflow specification and implementation. We then propose approaches to coping with each of them.
15896075
Effective bandwidth-based QoS provisioning for real-time audio/video streaming over MIMO-OFDM wireless networks
We propose a cross-layer design scheme to support the real-time quality of service (QoS) guarantees for heterogeneous mobile users over downlink MIMO-OFDM wireless networks. Inspired by the effective bandwidth theory originally established for wired networks, we develop the approach to apply the theory into wireless networks. Based on MIMO-OFDM infrastructure employed at the physical (PHY)-layer, we analytically derive the medium access control (MAC)-layer admission-control and time-slot allocation algorithms to guarantee the statistical delay-bound for different real-time users. Simulation results show that the proposed scheme can efficiently support the wireless QoS requirement for diverse real-time mobile users.
1484935
Improving genome rearrangement phylogeny using sequence-style parsimony
The study of genome rearrangements, the evolutionary events that change the order and strandedness of genes within genomes, presents new opportunities for discoveries about deep evolutionary events. The best software so far, GRAPPA, solves breakpoint and inversion phylogenies by scoring each tree topology through iterative improvements of internal node gene orders. We find that the greedy hill-climbing approach means the accuracy is limited because of multiple local optima. To address this problem, we propose integration GRAPPA with MPME, a string encoding of gene adjacency relationships whose optimal internal node assignments can be determined globally in polynomial time, to provide better initializations for GRAPPA. In simulation studies, the new algorithm yields shorter tree lengths and better accuracy in phylogeny reconstruction.
79892
Resource Allocation and Quality of Service Evaluation for Wireless Communication Systems Using Fluid Models
Wireless systems offer a unique mixture of connectivity, flexibility, and freedom. It is therefore not surprising that wireless technology is being embraced with increasing vigor. For real-time applications, user satisfaction is closely linked to quantities such as queue length, packet loss probability, and delay. System performance is therefore related to, not only Shannon capacity, but also quality of service (QoS) requirements. This work studies the problem of resource allocation in the context of stringent QoS constraints. The joint impact of spectral bandwidth, power, and code rate is considered. Analytical expressions for the probability of buffer overflow, its associated exponential decay rate, and the effective capacity are obtained. Fundamental performance limits for Markov wireless channel models are identified. It is found that, even with an unlimited power and spectral bandwidth budget, only a finite arrival rate can be supported for a QoS constraint defined in terms of exponential decay rate
46008282
A Head Gesture Recognition Algorithm
In this paper, we present a head gesture recognition algorithm that is based on the tracking technique developed by Kanade, Luca, and Tomasi (KaLuTo) and a one-class-in-one neural network algorithm. In our method, human skin colors are used to detect the head from complex backgrounds and the KaLuTo algorithm is applied to detect and track feature points on the head. Feature points tracked in successive frames are used to construct a feature vector as the input to the one-class-in-one neural network, which is employed to classify the head gestures into different classes. This method can offer some robustness to different background conditions. Experimental results prove the effectiveness of this method.