SETL implementation:data structures,primitives, and storage management

In this paper the application of preconditioning is extended to block iterative methods and shown to yield improved convergence rates for linear systems derived from the generalised Dirichlet problem.     

PoliawaC: design and evaluation of an awareness-enhanced groupware client

Presenting the activities of others at the user interface — thereby providing awareness — a is crucial aspect of CSCW systems. However, this problem is often neglected by existing designs. This paper discusses design requirements, introduces a notification design framework and describes the functionality ofPoliAwaC, a groupware client aimed specifically at supporting awarenes.PoliAwaC provides a variety of different graphical notification mechanisms which can be coupled to specific working situations using the AREA model. We also report on the evaluation of the system under real-life conditions in a German federal ministry.     

Reducing conflicts in groupware: metafunctions and their empirical evaluation

Certain functions in groupware affect more than one user who might have conflicting interests. To describe conflicts arising from the use of groupware functions, we distinguish the roles of the activator and the user affected. As technical means to lessen these conflicts, we develop two metafunctions: visibility of use and negotiability. We expect that these metafunctions reduce role-based conflicts and lead to higher acceptance of groupwaresystems among users. To examine these hypotheses we performed an empirical study in six different organizations. Using scenarios to present different design options to users, we confirmed most of our assumptions. Implications of these findings for the design of groupware are discussed.     

Reducing conflicts in groupware: Metafunctions and their empirical evaluation

Certain functions in groupware affect more than one user who might have conflicting interests. To describe conflicts arising from the use of groupware functions, we distinguish the roles of the activator and the user affected. As technical means to lessen these conflicts, we develop two metafunctions: visibility of use and negotiability. We expect that these metafunctions reduce role-based conflicts and lead to higher acceptance of groupwaresystems among users. To examine these hypotheses we performed an empirical study in six different organizations. Using scenarios to present different design options to users, we confirmed most of our assumptions. Implications of these findings for the design of groupware are discussed.     

Developing groupware for requirements negotiation: lessons learned

Defining requirements is a complex and difficult process, and defects in the process often lead to costly project failures. There is no complete and well-defined set of requirements waiting to be discovered in system development. Different stakeholders: users, customers, managers, domain experts, and developers, come to the project with diverse expectations and interests. Requirements emerge in a highly collaborative, interactive, and interdisciplinary negotiation process that involves heterogeneous stakeholders. At the University of Southern California's Center for Software Engineering, we have developed a series of groupware implementations for the WinWin requirements negotiation approach. The WinWin approach involves having a system's success-critical stakeholders participate in a negotiation process so they can converge on a mutually satisfactory or win-win set of requirements. The WinWin groupware system, which has evolved over four generations, enables and facilitates heterogeneous stakeholder participation and collaboration. Each generation reflects an increase in our understanding of what is needed for successful WinWin groupware operations and technology support. The authors present the major lessons they learned during WinWin's development     

Getting used with groupware: a first class experience

This article reports on an empirical investigation of long-term use of a groupware system in a spatially and massively distributed network of educators. It is a case study based investigation aimed at understanding the impacts of collaboration technology in supporting social interaction. The paradigm of social constructivism and the perspective of structuration are proposed as frameworks for understanding the impacts of technology on mediating social interaction. Utilizing these perspectives in an empirical investigation, the case study findings demonstrate how collaboration technology can serve as a change agent in transforming the culture and structure of social interaction. This is enacted in two ways: through the various meanings which people construct when interacting with technology and in benefiting from the structural properties of a system through its technical affordances.     

Cords: geometric curve primitives for modeling contact

Curves are perhaps the most versatile of modeling primitives in computer graphics. They define a rough structure for many surface-generation algorithms and are often fit to meaningful surface features for further shape modeling. Deformable objects such as hair and fur are simulated on finite element curve discretizations. Motion paths for planning and animation applications are tied to underlying curves. In this article we present a geometric curve primitive, known as a cord, which allows for interactive modeling of curves that contact complex geometry.     

A coordination framework and architecture for internet groupware

We discuss a group coordination architecture to support Internet-wide distributed collaboration, in particular for WWW-based distance education. With the current surge in e-commerce and Web-centric information exchange among users, the need for systems offering better telepresence and interaction capabilities becomes tangible. Group coordination in distributed systems and networked multimedia systems has many faces manifested in a variety of user interfaces and network protocols. However, to date no general methodology exists for engineering group coordination protocols to streamline the deployment of remote learning and collaboration environments. The objective of this article is to identify the key elements of a general group coordination framework, complementing existing group membership and multicast dissemination models, and to set the cornerstones for a coordination architecture which may be used to leverage the rapid development of group-oriented distributed collaborative applications in the Internet, for example for distance education, distributed scientific simulation and visualization, or similar applications.     

Towards goal-directed biped locomotion: Combining CPGs and motion primitives

In this paper it is presented a CPG approach based on phase oscillators to bipedal locomotion where the designer with little a priori knowledge is able to incrementally add basic motion primitives, reaching bipedal walking and other locomotor behaviors as final result. The proposed CPG aims to be a model free solution for the generation of bipedal walking, not requiring the use of inverse kinematical models and previously defined joint trajectories.The proposed incremental construction of bipedal walking allows an easier parametrization and performance evaluation throughout the design process. Furthermore, the approach provides for a developmental mechanism, which enables progressively building a motor repertoire. It would easily benefit from evolutionary robotics and machine learning to explore this aspect.The proposed CPG system also offers a good substrate for the inclusion of feedback mechanisms for modulation and adaptation. It is explored a phase regulation mechanism using load sensory information, observable in vertebrate legged animals.Results from simulations, on HOAP and DARwIn-OP in Webots software show the adequacy of the locomotor system to generate bipedal walk on different robots. Experiments on a DARwIn-OP demonstrates how it can accomplish locomotion and how the proposed work can generalize, achieving several distinct locomotor behaviors.     

Secrets to success and fatal flaws: the design of large-display groupware

Research in the field of large-display groupware applications has yet to yield a killer app, a common look and feel for applications, or a set of broadly applicable design principles. It's therefore difficult to understand what constitutes a successful large-display groupware application and what affects their adoption. Although large-display groupware faces many of the same adoption and use challenges as conventional desktop groupware, how people perceive and interact with large-display groupware yields some unique challenges. We've built and evaluated several large-display groupware systems that address various workgroups, functions, and environments. This experience has given us broad expertise regarding the social dynamics and technical challenges surrounding large-display groupware's design. To enhance our understanding of these challenges, we've also undertaken a broad survey of existing large-display groupware systems to understand how their purpose, design, and deployment affect the success of their integration into everyday tasks and practices.     

Automatic decomposition of time series into step, ramp, and impulse primitives

Time series data that can be modeled as linear combinations of weighted and shifted primitive functions such as ramps, steps and impulses are representative of many industrial, manufacturing, and business processes. Data of this type also are found in statistical process control, structural health monitoring, and other system diagnosis applications. Often, the existence of one or more of these primitive functions may be indicative of the occurrence of a specific process event, making their detection and interpretation of great interest. The human eye is an exceptional tool at this kind of pattern recognition. However, for processes that generate large amounts of data the human eye encounters difficulties related to speed and consistency necessitating an automated approach. In this paper, we consider the problem of decomposing a time series into its steps, ramps, and impulses constituents and expressing it as a linear combination of weighted and shifted versions of these primitives. We express the problem as a least squares error minimization coupled with a combinatorial search to arrive at an acceptable decomposition. We show that under certain conditions, such decomposition is possible and can be obtained efficiently using a sliding window approach. We illustrate the results with several examples.     

Ex-W-Pert system: A Web-based distributed expert system for groupware design

The World Wide Web (Web) allows people at remotely located sites to communicate and share their ideas using a common communication protocol. A common use of the Web system is running a client application, using a browsing tool, by pointing to a local or proxy server to browse data written in the hypertext format that contains anchors that address other URLs. In this paper a new application of the Web system for sharing knowledge-based systems and groupware development activities is introduced. An architecture for a Web-based Distributed Expert System (Ex-W-Pert System) is proposed and an implementation of the proposed architecture in groupware design is demonstrated. The resources and knowledge bases are distributed and can be accessed through the internet.     

Action recognition and understanding through motor primitives

In robotics, recognition of human activity has been used extensively for robot task learning through imitation and demonstration. However, there has not been much work performed on modeling and recognition of activities that involve object manipulation and grasping. In this work, we deal with single arm/hand actions which are very similar to each other in terms of arm/hand motions. The approach is based on the hypothesis that actions can be represented as sequences of motion primitives. Given this, a set of five different manipulation actions of different levels of complexity are investigated. To model the process, we use a combination of discriminative support vector machines and generative hidden Markov models. The experimental evaluation, performed with 10 people, investigates both the definition and structure of primitive motions, as well as the validity of the modeling approach taken.     

Negotiability: a metafunction to tailor access to data in groupware

Functions which control access to data in groupware should be designed flexibly by offering different options to end users. However, conflicts might arise among different end users in the process of selecting one of these options. To support users in finding a consensual solution for these conflicts, we propose a metafunction called 'negotiability'. We propose to define and explore the concept of 'negotiability', and discuss its application to access control, concurrency control, and consistency control. We assume that negotiability can play an important role in tailoring these mechanisms and supporting a co-operative use of system's flexibility.     

LICRA: A replicated-data management algorithm for distributed synchronous groupware applications

Replicated data consistency is a key issue in the design of distributed real time groupware applications. In this paper, we propose a new protocol to cope with this problem. The proposed algorithm guarantees an optimal response time while ensuring data consistency at system quiescence. The originality of our proposition relies on the fact that neither locks nor clocks nor global information are required to establish data consistency. Instead, direct dependency relations between generated operations as well as operation transformation mechanism are used. The coupling of the above two mentioned mechanisms is shown to realize a good trade-off between the different requirements of groupware applications. Advantages of our approach are illustrated by comparing the algorithm to two well known optimistic concurrency control protocols for groupware applications: dOPT and ORESTE.     

Virtual team awareness and groupware support: an evaluation of the TeamSCOPE system

This paper overviews a Web-based collaborative system called TeamSCOPE that has been designed to support awareness needs of globally distributed teams. Four types of awareness needs of virtual teams are defined and the awareness support features of TeamSCOPE are described. The usage patterns of eight globally distributed engineering design teams are outlined, and evaluation results are provided. Findings illustrate how group process interacts with technology to create design challenges in the support of virtual team awareness needs.