The capabilities for representing and reasoning about three-dimensional (3-D) objects are essential for knowledge-based, 3-D photointerpretation systems that combine domain knowledge with image processing, as demonstrated by 3- D Mosaic and ACRONYM. A practical framework for geometric representation and reasoning must incorporate projections between a two-dimensional (2-D) image and a 3-D scene, shape and surface properties of objects, and geometric and topological relationships between objects. In addition, it should allow easy modification and extension of the system's domain knowledge and be flexible enough to organize its reasoning efficiently to take advantage of the current available knowledge. This system uses frames to represent objects such as buildings and walls, geometric features such as lines and planes, and geometric relationships such as parallel lines.

Our guest editor is Avi Kak, of Purdue University. We also round out the issue with the final installment of Steven Frank's Swartout, on an AAAIsponsored Planning Workshop, held last year. "open-ended" (i.e., almost any aspect of the experienced world might be Book reviews should be submitted to the Book Review Editor, Bruce D'Ambrosio, Computer Science Department, Oregon State University, Corvallis, OR 97331 (503) 754.4466 Advertising rates and media kits are available upon request from AI Magazine, 445 Burgess Drive, Menlo Park, CA 94025 Telephone (415) 328.3123

Subsequent chapters extend these techniques to the recognition of isolated curved objects using a graph model, interpretation of imperfect regions using a scene model, and recognition of multiple objects using Z-D object models. Shirai proceeds in a logical fashion two-dimensional pattern (2-D) recognition, pleted, the author concentrates on the from 2-D analysis, to line drawing such as character recognition 3-D world. The next two chapters deal interpretation, to the analysis of range or the recognition of silhouettes. The chapter on range data irregular objects using fractals and brief description of the field, the processing is a very strong one that superquadrics. This is followed by a reference source for researchers analysis, edge linking and following, chapter on three-dimensional description in 3-D vision.

This is a summary of the Workshop on Planning that was sponsored by the Defense Advanced Research Project Agency and held in Santa Cruz, California, on October 21-23, 1987. The purpose of this workshop was to identify and explore new directions for research in planning.

Sometimes less ambiguous, are extremely complex.

However, a substantial amount of research is still needed to solve many difficult problems before real-time expert systems can enhance current monitoring and control systems. In this article, we examine how the real-time problem domain is significantly different from those domains which have traditionally been solved by expert systems. The survey is divided into three areas: applications, tools, and theoretic issues. From the results of the survey, we identify a set of real-time research issues that have yet to be solved and point out limitations of current tools for real-time problems.

Real-time domains present a new and challenging environment for the application of knowledge-based problem-solving techniques. However, a substantial amount of research is still needed to solve many difficult problems before real-time expert systems can enhance current monitoring and control systems. In this article, we examine how the real-time problem domain is significantly different from those domains which have traditionally been solved by expert systems. We conduct a survey on the current state of the art in applying knowledge-based systems to real-time problems and describe the key issues that are pertinent in a real-time domain. The survey is divided into three areas: applications, tools, and theoretic issues. From the results of the survey, we identify a set of real-time research issues that have yet to be solved and point out limitations of current tools for real-time problems. Finally, we propose a set of requirements that a real-time knowledge-based system must satisfy.

Letters to the editor on the lack of a central index to the field's published works and the fact that many original works are not published in journals; praise for Letovsky article -- stimulating and amusing. felt subsequent letters to editors were full of bombastic indignation; criticism of Kasday letter about it and Bob Engelmore's weak support of the article; dualism in regards to Letovsky letter; and a reply to criticism by Letovsky, acknowledging diaristic form.

This review examines two important works in decision analysis: Howard and Matheson's The Principles and Applications of Decision Analysis, and Winterfeldt and Edwards's "Decision Analysis and Behavioral Research.