Macsyma: A personal history

The Macsyma system arose out of research on mathematical software in the AI group at MIT in the 1960s. Algorithm development in symbolic integration and simplification arose out of the interest of people, such as the author, who were also mathematics students. The later development of algorithms for the GCD of sparse polynomials, for example, arose out of the needs of our user community. During various times in the 1970s the computer on which Macsyma ran was one of the most popular nodes on the ARPANET. We discuss the attempts in the late 70s and the 80s to develop Macsyma systems that ran on popular computer architectures. Finally, we discuss the impact of the fundamental ideas in Macsyma on the author’s current research on large scale engineering and socio-technical systems.     

Reasoning about Knowledge: A Response by the Authors

Minds and Machines -     

Generalization to Novel Views: Universal,Class-based,and Model-based Processing

A major problem in object recognition is that a novel image of a given object can be different from all previously seen images. Images can vary considerably due to changes in viewing conditions such as viewing position and illumination. In this paper we distinguish between three types of recognition schemes by the level at which generalization to novel images takes place: universal, class, and model-based. The first is applicable equally to all objects, the second to a class of objects, and the third uses known properties of individual objects. We derive theoretical limitations on each of the three generalization levels. For the universal level, previous results have shown that no invariance can be obtained. Here we show that this limitation holds even when the assumptions made on the objects and the recognition functions are relaxed. We also extend the results to changes of illumination direction. For the class level, previous studies presented specific examples of classes of objects for which functions invariant to viewpoint exist. Here, we distinguish between classes that admit such invariance and classes that do not. We demonstrate that there is a tradeoff between the set of objects that can be discriminated by a given recognition function and the set of images from which the recognition function can recognize these objects. Furthermore, we demonstrate that although functions that are invariant to illumination direction do not exist at the universal level, when the objects are restricted to belong to a given class, an invariant function to illumination direction can be defined. A general conclusion of this study is that class-based processing, that has not been used extensively in the past, is often advantageous for dealing with variations due to viewpoint and illuminant changes.     

Term distribution visualizations with Focus+Context

Many text searches are meant to identify one particular fact or one particular section of a document. Unfortunately, predominant search paradigms focus mostly on identifying relevant documents and leave the burden of within-document searching on the user. This research explores term distribution visualizations as a means to more clearly identify both the relevance of documents and the location of specific information within them. We present a set of term distribution visualizations, introduce a Focus+Context model for within-document search and navigation, and describe the design and results of a 34-subject user study. This user study shows that these visualizations—with the exception of the grey scale histogram variant—are comparable in usability to our Grep interface. This is impressive given the substantial experience of our users with Grep functionality. Overall, we conclude that user do not find this visualization model difficult to use and understand.     

The effect of cognitive and affective aspects on usability

Studies on customer’s needs, desires and preferences have become highly important in the product design and development process. One consideration in usability is the cognitive aspect, which is related to the accommodation and evaluation of human cognitive capabilities, limitations and tendencies. In addition to the cognitive aspect, a recent study has shown that the affective aspect has been considered in the evaluation of product usability. Thus, both cognitive and affective aspects are deemed to be important for product design and the development process. Inherently, both aspects deliver complete human and product interaction and experience. However, studies that consider the affective process as a complement to the cognitive process for usability are relatively rare. To address this gap, this study discusses how an integrative framework of the cognitive and affective aspects can be applied to a product for usability assessment via empirical studies on e-commerce and e-learning platforms. The sample involved 230 respondents, using purposive sampling. The result shows that both cognitive and affective aspects have a significant effect, although with different weights. The affective aspect has been shown to improve product usability and user’s acceptance.     

Influence of substrate temperature on crystalline copper aluminium oxide thin films synthesized through chemical spray pyrolysis (CSP) technique

Copper aluminium oxide (CuAlO₂) of well ordered crystalline films were deposited on to glass substrates with Cu/Al ratio r = 0.8 at the substrate temperatures of 250, 300, 350, 400 and 450 °C. Films which were characterized had a thickness of the order of few micrometers. Films deposited at the optimized deposition temperature (450 °C) revealed well-crystalline CuAlO₂ phase with XRD peak at 2θ = 31.7° corresponds to (006) reflection. The peak positions of the core level XPS spectra, confirm the presence of delafossite CuAlO₂ phase. The optical transmission of 80 % has been observed in the visible spectrum. The obtained band gap energy is 4.1 eV. From the observed results it was evidenced that the substrate temperature has strong influence on the structural and optical properties of the spray pyrolysed copper aluminium oxide films.     

Wind characteristics and energy potential assessment in Akure,South West Nigeria: econometrics and policy implications

This paper analysed 11 years of daily mean wind-speed data, measured at Akure, Ondo State, Nigeria, using Weibull and Rayleigh distribution functions. While both distributions showed good agreements in extreme-value estimation patterns, investigation of their wind-speed characteristics modelling criteria, using goodness-of-fit statistics, revealed that the wind data followed the Weibull more than Rayleigh. Monthly wind-speed of Akure city ranged from 1.41 to 4.24 m/s by the Weibull fittings and from 1.40 to 4.16 m/s by the Rayleigh fittings. Overall results, of 2.71 m/s (Weibull) or 2.70 m/s (Rayleigh) mean wind-speed and 18.51 W/m² (Weibull) or 22.26 W/m² (Rayleigh) mean power density, indicated Akure a low wind-speed site, requiring low wind-speed turbine for generating wind energy. Econometric analyses of power output simulations using such turbine system resulted in affordable wind energy cost. These bear policy implications for sustainable wind energy usage in this and similar regions of the world.     

Agent-based framework for intelligent natural language interface

In this contribution, we present a framework for an intelligent natural language interface (NLI) that suits the need of embedded platform, using agent-based approach. The proposed framework is motivated by an ongoing speech technology research project aimed at developing a generic synthesizer for information disseminating systems in local languages. The architecture is based on various forms of action representations with a sequence of transformations that converts users’ input (text or speech) into a suitable set of agent actions that produce response to the input. This approach incrementally minimizes the complexity and ambiguity of the natural language input by using predefined sets of interim actions at different levels, hence, increasing the robustness and reliability of the NLI.