Roger W. Ehrich

Bio: Roger W. Ehrich is an academic researcher from Virginia Tech. The author has contributed to research in topics: The Internet & Usability. The author has an hindex of 8, co-authored 23 publications receiving 265 citations.

Computer analysis of user interfaces based on repetition in transcripts of user sessions

Abstract: It is generally acknowledged that the production of quality user interfaces requires a thorough understanding of the user and that this involves evaluating the interface by observing the user working with the system, or by performing human factors experiments. Such methods traditionally involve the use of video tape, protocol analysis, critical incident analysis, etc. These methods require time consuming analyses and may be invasive. In addition, the data obtained through such methods represent a relatively small portion of the use of a system. An alternative approach is to record all user input and systems output, i.e., log the user session. Such transcripts can be collected automatically and non-invasively over a long period of time. Unfortunately, this produces voluminous amounts of data. There is, therefore, a need for tools and techniques that allow an evaluator to identify potential performance and usability problems from such data. It is hypothesized that repetition of user actions is an important indicator of potential user interface problems.

QUIZIT: An Interactive Quiz System for WWW-based Instruction.

Abstract: In distance learning and self-paced instruction, student evaluation with prompt feedback has always been a critical issue. Instructors and teaching assistants are often confronted with scores of e-mail messages per day from students, the need to work night and day to grade exams, and heavy workloads late in the term. This paper describes the design of an automatic evaluation system that aims to eliminate some of the workload on instructors, by providing a convenient way of authoring interactive quizzes while addressing issues of reuse, portability and immediate feedback to students. We build on the standard models of Computer-based Training (CBT) and Web-based Training (WBT) systems, showing how we can combine their best features and overcome some of their problems, keeping in mind the specific requirements of our educational environment.

Chat rooms as Virtual Hangouts for rural elementary students

Abstract: This article is a description of how 24 rural, 5th-grade students with home Internet access used an Internet chat application after school and how this usage changed during a one-year period. Study results have implications for curriculum design (e.g., how teachers can use chat to stimulate collaborative learning after school), student-teacher interactions (e.g., how can teachers maintain their authority in this new environment), and research (e.g., how does gender affect student usage of chat).

Usability Engineering

Abstract: From the Publisher: Written by the author of the best-selling HyperText & HyperMedia, this book provides an excellent guide to the methods of usability engineering. Special features: emphasizes cost-effective methods that will help developers improve their user interfaces immediately, shows you how to avoid the four most frequently listed reasons for delay in software projects, provides step-by-step information about which methods to use at various stages during the development life cycle, and offers information on the unique issues relating to informational usability. You do not need to have previous knowledge of usability to implement the methods provided, yet all of the latest research is covered.

SUSAN—A New Approach to Low Level Image Processing

Abstract: This paper describes a new approach to low level image processing; in particular, edge and corner detection and structure preserving noise reduction. Non-linear filtering is used to define which parts of the image are closely related to each individual pixel; each pixel has associated with it a local image region which is of similar brightness to that pixel. The new feature detectors are based on the minimization of this local image region, and the noise reduction method uses this region as the smoothing neighbourhood. The resulting methods are accurate, noise resistant and fast. Details of the new feature detectors and of the new noise reduction method are described, along with test results.

Markov Random Field Texture Models

Abstract: We consider a texture to be a stochastic, possibly periodic, two-dimensional image field. A texture model is a mathematical procedure capable of producing and describing a textured image. We explore the use of Markov random fields as texture models. The binomial model, where each point in the texture has a binomial distribution with parameter controlled by its neighbors and ``number of tries'' equal to the number of gray levels, was taken to be the basic model for the analysis. A method of generating samples from the binomial model is given, followed by a theoretical and practical analysis of the method's convergence. Examples show how the parameters of the Markov random field control the strength and direction of the clustering in the image. The power of the binomial model to produce blurry, sharp, line-like, and blob-like textures is demonstrated. Natural texture samples were digitized and their parameters were estimated under the Markov random field model. A hypothesis test was used for an objective assessment of goodness-of-fit under the Markov random field model. Overall, microtextures fit the model well. The estimated parameters of the natural textures were used as input to the generation procedure. The synthetic microtextures closely resembled their real counterparts, while the regular and inhomogeneous textures did not.

Computer and Robot Vision

Abstract: Computer and Robot Vision Vol. 1, by R.M. Haralick and Linda G. Shapiro, Addison-Wesley, 1992, ISBN 0-201-10887-1.