148806746
Human-computer interaction: psychology as a science of design.
1921535
Interface design issues for advice-giving expert systems
Advice giving could become the first successful domain for intelligent interfaces.
14110921
The reuse of uses in Smalltalk programming
Software reuse, a long-standing and refractory issue in software technology, has been specifically emphasized as an advantage of the object-oriented programming paradigm. We report an empirical study of expert Smalltalk programmers reusing user interface classes in small graphical applications. Our primary goal was to develop a qualitative characterization of expert reuse strategies that could be used to identify requirements for teaching and supporting reuse programming. A secondary interest was to demonstrate to these experts the Reuse View Matcher—a prototype reuse tool—and to collect some initial observations of this tool in use during reuse programming. We observed extensive “reuse of uses” in the programmers' work: they relied heavily on code in expample applications that provided an implicit specification for reuse of the target class. We called this implicit specification a “usage context.” The programmers searched for relevant usage contexts early. They repeatedly evaluated the contextualized information to develop solution plans, and they borrowed and adapted it when the sample context suited their immediate reuse goals. The process of code development was highly dynamic and incremental; analysis and implementation were tightly interleaved, frequently driven by testing and debugging. These results are considered in terms of the tradeoffs that inhere in the reuse of uses and the teaching and tool support that might improve the efficiency and accuracy of this approach to reuse.
774
Can Subcategorisation Probabilities Help a Statistical Parser
Research into the automatic acquisition of lexical information from corpora is starting to produce large-scale computational lexicons containing data on the relative frequencies of subcategorisation alternatives for individual verbal predicates. However, the empirical question of whether this type of frequency information can in practice improve the accuracy of a statistical parser has not yet been answered. In this paper we describe an experiment with a wide-coverage statistical grammar and parser for English and subcategorisation frequencies acquired from ten million words of text which shows that this information can significantly improve parse accuracy.
257038
Apportioning Development Effort in a Probabilistic LR Parsing System Through Evaluation
We describe an implemented system for robust domain-independent syntactic parsing of English, using a unification-based grammar of part-ofspeech and punctuation labels coupled with a probabilistic LR parser. We present evaluations of the system’s performance along several different dimensions; these enable us to assess the contribution that each individual part is making to the success of the system as a whole, and thus prioritise the effort to be devoted to its further enhancement. Currently, the system is able to parse around 80% of sentences in a substantial corpus of general text containing a number of distinct genres. On a random sample of 250 such sentences the system has a mean crossing bracket rate of 0.71 and recall and precision of 83% and 84% respectively when evaluated against manually-disambiguated analyses.
1970300
Acting out the future: a process for envisionment
It is difficult to design innovative information and communication technologies to meet needs that will emerge from future interactions between users, technologies and their situations of use. We have been using scenarios that are acted out as a way of envisioning the future. This paper describes some of the core dilemmas of innovative design. It draws on our existing work as well as ideas from a range of disciplines to present a ‘light’ but useful envisionment process that may be applied to commercial design problems.
15057511
Completing design in use: closing the appropriation cycle
Users appropriate a technology innovation as they adapt and adapt to its capabilities. This paper argues that the appropriation of technology innovations – information and communication technologies such as devices and systems – is actually part of the design process. The design of a technology innovation is completed by users as they appropriate it. The contributions of the paper are to draw attention to the crucial role played by users’ actions in completing the design process and to examine the implications for the design and implementation of technology innovations. The challenge for designers is to design malleable technologies that can be adapted to users’ organisational, social and personal practices, and then to harvest users’ needs from the appropriated innovation in order to improve its design. For managers, trainers and IS staff involved in the implementation of innovations, the challenge is to encourage and support users’ appropriation activities.
39105600
Estimating the Reliability of Regeneration-Based Replica Control Protocols
The accessibility of vital information can be enhanced by replicating the data on several sites and employing a consistency control protocol to manage the replicas. The reliability of a replicated data object depends on maintaining a viable set of current replicas. When storage is limited, it may not be feasible to simply replicate a data object at enough sites to achieve the desired level of reliability. Regeneration approximates the reliability provided by additional replicas for a modest increase in storage costs, and is applicable whenever a new replica of a data object can be created faster than a system failure can be repaired. Regeneration enhances reliability by creating new replicas on other sites in response to site failures. Several strategies for replica maintenance are considered, and the benefits of each are analyzed using simulation and both algebraic and numeric solutions to systems of differential equations. >