Automatic generation of starvation-free semaphore solutions to general mutual exclusion problems is discussed. A reduction approach is introduced for recognizing edge-solvable problems, together with an O(N^2) algorithm for graph reduction, where N is the number of nodes. An algorithm for the automatic generation of starvation-free edge-solvable solutions is presented. The solutions are proved to be very efficient. For general problems, there are two ways to generate efficient solutions. One associates a semaphore with every node, the other with every edge. They are both better than the standard monitor—like solutions. Besides strong semaphores, solutions using weak semaphores, weaker semaphores and generalized semaphores are also considered. Basic properties of semaphore solutions are also discussed. Tools describing the dynamic behavior of parallel systems, as well as performance criteria for evaluating semaphore solutions are elaborated.

This research is concerned with some aspects of the retrieval of information from database systems by casual, naive computer users. A "casual user" is defined as an individual who only wishes to execute queries perhaps once or twice a month, and a "naive user" is someone who has little or no expertise in operating a computer and, more specifically for the purposes of this study, is not practiced at querying a database. The research initially focuses on a specific group of casual, naive users, namely a group of clinicians, and analyzes their characteristics as they pertain to the retrieval of information from a computer database. The characteristics thus elicited are then used to create the requirements for a database interface that would, potentially, be acceptable to this group. An interface having the desired requirements is then proposed. This interface consists, from a user's perspective, of three basic components. A graphical model gives a picture of the database structure. Windows give the ability to view different areas of the database, physically group together items that come under one logical heading and provide the user with immediate access to the data item names used by the system. Finally, a natural language query …

This study models the human process of music cognition on the digital computer. The definition of music cognition is derived from the work in music cognition done by the researchers Carol Krumhansl and Edward Kessler, and by Mari Jones, as well as from the music theories of Heinrich Schenker. The computer implementation functions in three stages. First, it translates a musical "performance" in the form of MIDI (Musical Instrument Digital Interface) messages into LISP structures. Second, the various parameters of the performance are examined separately a la Jones's joint accent structure, quantified according to psychological findings, and adjusted to a common scale. The findings of Krumhansl and Kessler are used to evaluate the consonance of each note with respect to the key of the piece and with respect to the immediately sounding harmony. This process yields a multidimensional set of points, each of which is a cognitive evaluation of a single musical event within the context of the piece of music within which it occurred. This set of points forms a metric space in multi-dimensional Euclidean space. The third phase of the analysis maps the set of points into a topology-preserving data structure for a Schenkerian-like middleground structural analysis. This …

Every business has to keep records. Sometimes these records have to be presented in a standardized form, or more often they can be arranged in any way that suits the user. Business records are of little use unless they can be referred to quickly, to provide information when it is required. In computer systems it is essential to be able to recognize any particular record in a data file which is a collection of similar records kept on secondary computer storage devices.

The purpose of this project is 1) to create a Thai character set for text processing, 2) to write a text processing program for the character set, and 3) to allow users to create and save the text.

Among the early applications of computers, one can find frequent mention of intelligent instructional systems. Such intelligent instructional systems represent a new generation of learner-based computer aided instruction, preceded in time by the original frame-based systems and an intervening generation of expert-based CAI. The history of CAI is characterized by three generations: Frame-based CAI, Expert-based CAI and Learner-based CAI.