Kenneth C. Smith

A second-generation current conveyor and its applications

A recent publication [l] introduced the concept of current conveying and an implementation in the form of a circuit building block termed the current conveyor (CC). This block has proven to be useful in many inst.rumentation applications, some of which have already been test)ed and reported [2], [3], while others are still under investigation. This correspondence introduces another new building block embodying the current conveying concept, but with different and more versatile terminal characteristics. This new block is considered to be a secondgeneration current conveyor,1 and h.ence is termed CC II.2 Application of CC II to the areas of active network synthesis and analog computation will be considered..

A multi-touch three dimensional touch-sensitive tablet

A prototype touch-sensitive tablet is presented. The tablets main innovation is that it is capable of sensing more than one point of contact at a time. In addition to being able to provide position coordinates, the tablet also gives a measure of degree of contact, independently for each point of contact. In order to enable multi-touch sensing, the tablet surface is divided into a grid of discrete points. The points are scanned using a recursive area subdivision algorithm. In order to minimize the resolution lost due to the discrete nature of the grid, a novel interpolation scheme has been developed. Finally, the paper briefly discusses how multi-touch sensing, interpolation, and degree of contact sensing can be combined to expand our vocabulary in human-computer interaction.

The current conveyor—A new circuit building block

A new circuit concept applicable to a basic building block in a variety of instrumentation and communication systems is introduced. The new concept is called current conveying and its implementation a current conveyor.

Magnetoresistive random access memory using magnetic tunnel junctions

Magnetoresistive random access memory (MRAM) technology combines a spintronic device with standard silicon-based microelectronics to obtain a combination of attributes not found in any other memory technology. Key attributes of MRAM technology are nonvolatility and unlimited read and write endurance. Magnetic tunnel junction (MTJ) devices have several advantages over other magnetoresistive devices for use in MRAM cells, such as a large signal for the read operation and a resistance that can be tailored to the circuit. Due to these attributes, MTJ MRAM can operate at high speed and is expected to have competitive densities when commercialized. In this paper, we review our recent progress in the development of MTJ-MRAM technology. We describe how the memory operates, including significant aspects of reading, writing, and integration of the magnetic material with CMOS, which enabled our recent demonstration of a 1-Mbit memory chip. Important memory attributes are compared between MRAM and other memory technologies.

RAP: an associative processor for data base management

Recent concepts in data base management systems (DBMS) necessitate making the logical view and the physical representation of data distinct from each other. Currently, this requirement has to be realized in the environment of conventional Von Neumann architecture. This creates the need for several levels of indirection for mapping one structure into the other. Also, efficient search mechanisms are needed to handle large data bases within concurrent processing and on-line response limits. The implementation of these requirements results in software complexities and inefficiencies in the following way. Pointer mechanisms for mapping structures and providing fast access paths have to be implemented by software and data. These pointers are extra data requiring extensive overhead in storage, access time, and maintenance.

Towards a comprehensive user interface management system

A UIMS developed at the University of Toronto is presented. The system has two main components. The first is a set of tools to support the design and implementation of interactive graphics programs. The second is a run-time support package which handles interactions between the system and the user (things such as hit detection, event detection, screen updates, and procedure invocation), and provides facilities for logging user interactions for later protocol analysis. The design/implementation tool is a preprocessor, called MENULAY, which permits the applications programmer to use interactive graphics techniques to design graphics menus and their functionality. The output of this preprocessor is high-level code which can be compiled with application-specific routines. User interactions with the resulting executable module are then handled by the run-time support package. The presentation works through an example from design to execution in a step-by-step manner.

A multiple valued logic: a tutorial and appreciation

This tutorial places the developments and potential of multiple-valued signals and logic in the relevant context of binary and two-valued signals. It covers: the role of multivalued logic (MVL) in the binary world; multivalued representation; binary-related radices; multivalued functions; storage techniques in MVL; and implementation issues. An overview of applications is included.<<ETX>>

Three-dimensional location estimation of circular features for machine vision

A closed-form analytical solution to the problem of 3D estimation of circular-feature location is presented. Two different cases are considered: 3D orientation and position estimation when the radius is known and when it is not known. Extension of the method to general 3D quadratic features is also addressed. Simulated experimental results obtained for all three cases verified the analytical method. In the case of real experiments, a set of circles located on a calibration plate, whose locations were known with respect to a reference frame, were used for camera calibration as well as for the application of the method. A sequential compensation procedure was applied to the input gray-level image to compensate for distortion. These results also showed the validity of the process and the applicability of the analytical method. >

Reactive environments

increasingly widespread, we are confronted with the burden of controlling a myriad of complex devices in our day-today activities. While many people today could hardly imagine living in electronics-free homes or working in offices without computers, few of us have truly mastered full control of our VCRs, microwave ovens, or office photocopiers. Rather than making our lives easier, as technology was intended to do, it has complicated our activities with lengthy instruction manuals and confusing user interfaces. Designers have been trying to make the computer more “user-friendly” ever since its inception. The last two decades have brought us the notable advances of keyboard terminals, graphics displays, and pointing devices, as well as the graphical user interface, introduced in 1981 by the Xerox Star and popularized by the Apple Macintosh. Most recently, we have seen the emergence of pen-based and portable computers. However, despite this progress of interface improvements, very little has changed in terms of how we work with these machines. The basic rules of interaction are the same as they were in the days of the ENIAC: users must engage in an explicit, machine oriented dialogue with the computer rather than interact with the computer as they do with other people. In the last few years, computer scientists have begun talking about a new approach to human-computer interaction in which computing would not necessitate sitting in front of a screen and isolating ourselves from the world around us. Instead, in a computer-augmented environment, electronic systems could be merged into the physical world to provide computer functionality to everyday objects. This idea is exemplified by Ubiquitous Computing (UbiComp)

A Many-Valued Algebra for Switching Systems

Many-valued switching systems have been of considerable academic interest, despite the apparent inability to use them in practical applications. The main drawbacks, as pointed out by a number of authors, are the difficulties associated with the implementation of the functional basic set and the lack of adequate simplification techniques.