While the technology underlying speech interfaces has improved in recent years, our understanding of the human side of speech interactions remains limited. This paper provides new insight on one important human aspect of speech interactions: the sense of agency - defined as the experience of controlling one's own actions and their outcomes. Two experiments are described. In each case a voice command is compared with keyboard input. Agency is measured using an implicit metric: intentional binding. In both experiments we find that participants' sense of agency is significantly reduced for voice commands as compared to keyboard input. This finding presents a fundamental challenge for the design of effective speech interfaces. We reflect on this finding and, based on current theory in HCI and cognitive neuroscience, offer possible explanations for the reduced sense of agency observed in speech interfaces.

Cognitive neuroscience defines the sense of agency as the experience of controlling one's own actions and, through this control, affecting the external world. We believe that the sense of personal agency is a key factor in how people experience interactions with technology. This paper draws on theoretical perspectives in cognitive neuroscience and describes two implicit methods through which personal agency can be empirically investigated. We report two experiments applying these methods to HCI problems. One shows that a new input modality - skin-based interaction - can substantially increase users' sense of agency. The second demonstrates that variations in the parameters of assistance techniques such as predictive mouse acceleration can have a significant impact on users' sense of agency. The methods presented provide designers with new ways of evaluating and refining empowering interaction techniques and interfaces, in which users experience an instinctive sense of control and ownership over their actions.

PrologueShor6ly after the collapse of Soviet domination in Eastern Europe, a Polish housewife was interviewed by Na6ional Public Radio.She complained that the introduction of free enterprise to Poland was a great inconvenience.Now, instead of shopping at the most conveniently located store, secure in the knowledge that prices were uniform, she had to go from store to store comparing prices, in order to be sure that she was making the best buy."Why should prices be different at each store?" she complained."After all, they are all selling the same things."On the surface, her remarks seem to make a great deal of sense.If we can find the fallacy in her thinking, we will learn a small lesson about a very important subject, free-market economics, and more relevantly, a big lesson about a less important subject, software reuse libraries.

Several efforts are currently underway to foster a marketplace for reusable software components based upon interoperating electronic libraries containing managed collections of components. In such a marketplace, it is necessary for potential users to be able to verify the origin of candidate components and to assure that they have not been modified by third parties. This paper proposes a method for providing the assurance through the application of modern encryption techniques.>

Does a single, general-purpose RSL or a domain-specific RSL provide the best method to leverage knowledge and assets across a large organization? My experience indicates the need for at least three fundamentally different types of libraries: local libraries; domain specific libraries; and reference libraries. Can RSLs can effectively interoperate across organizations? There are already come examples of the effective interoperation of reuse libraries. Does an RSL require a formal classification for components stored in the library? As collections grow, users will require more assistance in locating and selecting relevant candidates, but different classification mechanisms are relevant to different types of libraries. Must an RSL provide specialized reuse support, such as user registration, version control and problem notification? There will always be a role for libraries which are operated on a pro bone basis by members of the research community or other altruistic parties. On the other hand, as reuse transitions from a technological basis to an economic basis, there will be users willing to pay for additional services and there will be vendors willing to provide them.>

No abstract available.

Abstract Motivated by the study of large graphs with given degree and diameter, and the recent interest in the design of highly symmetric interconnection networks (e.g., the study of Cayley digraphs), we are led to the search for large vertex symmetric digraphs with given degree and diameter. The main result of this paper is the construction of a new class of vertex symmetric directed graphs, Γδ(D) (δ ≥ D) that have degree δ, diameter D, and (δ + 1)δ … (δ – D + 2) vertices. The graphs Γδ(D) are first found in the notation of Cayley coset digraphs. Then, we discover that they have a very simple representation in terms of sequences like the commonly studied networks such as the hypercube, de Bruijn graphs, and Kautz graphs. Based on the sequence representation, we give a simple shortest‐path routing scheme. We also show that the average distance in our digraph Γδ(D) is very close to its diameter D. As a consequence, it follows that the natural routing scheme, which is even simpler than the shortest‐path routing, is nearly optimal on an average basis. © 1993 by John Wiley & Sons, Inc.

A report is presented on a collection of constructions of symmetric networks that provide the largest known values for the number of nodes that can be placed in a network of a given degree and diameter. Some of the constructions are in the range of current potential engineering significance. The constructions are Cayley graphs of linear groups obtained by experimental computation.>