Constraints—A language for expressing almost-hierarchical descriptions

We present an interactive system organized around networks of constraints rather than the programs which manipulate them. We describe a language of hierarchical constraint networks. We describe one method of deriving useful consequences of a set of constraints which we call propagation. Dependency analysis is used to spot and track down inconsistent subsets of a constraint set. Propagation of constraints is most flexible and useful when coupled with the ability to perform symbolic manipulations on algebraic expressions. Such manipulations are in turn best expressed as alterations or augmentations of the constraint network.Almost-Hierarchical Constraint Networks can be constructed to represent the multiple viewpoints used by engineers in the synthesis and analysis of electrical networks. These multiple viewpoints are used in terminal equivalence and power arguments to reduce the apparent synergy in a circuit so that it can be attacked algebraically.     

Can preschool children invent addition algorithms?

Examined the patterns of reaction times that emerge when a child is taught a specific problem-solving procedure and then given extensive practice over many weeks. In 2 experiments, 10 pre-schoolers (average age 4 yrs 8 mo) who knew how to count but were unacquainted with arithmetic were taught a simple algorithm for solving single-digit addition problems and were then given extended practice. An S performing this algorithm would generate reaction times proportional to the sum of the addends. The main finding shows that, at the end of the extended practice phase, data of many Ss were best fitted by a different model predicting reaction times proportional to the minimum addend. This implies that these Ss were no longer using the algorithm they were originally taught. It is also interpreted as suggesting that they invented a more efficient procedure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Organic desorption from carbon—III. The effect of solvent in the desorption of phenol from dry carbon

The desorption of phenol from active carbon was studied using a continuous flow desorber. The system used was nearly water free to reduce water-phenol interactions. An attempt to correlate the desorption data with the physical properties of phenol and solvents, in addition to regular solution theory, proved unsuccessful. A thermodynamic approach using the linear free energy-enthalpy relationship produced a general trend by using the heat of solution for phenol in solution and a reasonable correlation using the heat of formation of the phenol-solvent hydrogen bond with the desorption data.     

La luminescence de l'europium divalent dans les fluoroberyllates alcalino-terreux

The M_1?xEu_xBeF₄ (M = Ca, Sr, Ba) phases are efficient UV phosphors. Emission consists of both a broad d-f band and narrow f-f lines, the relative intensities being strongly dependent on host lattice, europium content and temperature     

The internal friction of glasses

Basic fundamentals of the elastic behaviour of a standard linear solid and the internal friction technique based on this model are briefly described. The internal friction (Q ^–1) caused by various thermally activated processes in vitreous solids are reviewed for several glass compositions in relation to ionic mobility and other relevant properties. Similar relaxation mechanisms characterize many vitreous solids. The relaxation of alkali ions is essentially independent of the glass network former and has an activation energy of 15 to 25 kcal mol^–1. Other processes like the interaction of oxygen ions and protons, alkali ions and protons, mixed-alkali ion interaction and the motion of single bonded oxygen ions have an activation energy of 30 to 40 kcal mol^–1. The activation energy for relaxation of the glass network is 100 to 120 kcal mol^–1.     

Transients in Carbon Dioxide Stores

Physiologically correct models of the respiratory control system require accurate knowledge of the structure and dynamics of carbon dioxide stores of the body. Several models of these stores have been investigated and the computed results compared to experiment. The effect on these models of alterations in cardiac output, regional perfusion, and tissue absorptive capacity for carbon dioxide has been examined. Experimental results are best duplicated by a five venous compartment model of carbon dioxide stores with a low absorptive capacity for carbon dioxide during the first few minutes following a change in ventilation.     

Calculation by the Method of Finite Differences of the Temperature Distribution in Layered Tissues

A numerical approach to obtain the temperature distribution in layered tissues with thermal source and cooling inside the tissues is presented in this paper. This approach can be applied to problems with a distributed internal thermal source produced by external radiation such as microwave, ultrasound, and shortwave, or by internal increase of metabolic rate in live subjects. The exact mechanism of cooling is not discussed here, but it is assumed to be due to blood flow in vivo. The calculation of the temperature distribution in layered tissues is based on a linear model of the tissues that consists of several layers of different kinds of tissues separated by parallel boundaries. Some simple mathematical forms of the cooling functions are also assumed in this paper. The results obtained agree well with six available experiments.     

Computing with feeling

Computers are usually considered as manipulators of numbers, words and symbols: machines with which we communicate visually by printers, plotters and displays, and sometimes audibly through music synthesis and speech recognition. We are engaged in a project involving touch communication with computers in order to broaden computer graphics capability. Originally pioneered by Noll and by Batter and Brooks, touch communication with computers can link together brain, hands and computer to explore new worlds of felt imagery, worlds existing only in computer memory.Humans are distinguished from other animals particularly by two things: the hands, which allow fine manipulations of objects in the environment, and the brain, which permits thought. Touch communication with computers employs both of these most human capabilities. What we're searching for is a closer symbiosis between humans and machines, a partnership of two unlike species growing together as both learn to perform joint tasks better. This symbiosis demands a better interface where machine meets person.The first of our touch communication systems is a three-dimensional force-position system called “Touchy Feely” in which mechanical simplicity is gained by using a tetrahedral coordinate system, employing the computer to transform into other coordinate systems. We are also designing a force, torque, position and orientation system. “Touchy Twisty”, which will permit the user to feel the docking of one three-dimensional object with another: in other words, to allow the assembly of computer simulated objects.There are many applications of human-computer touch communication to research and learning, extending into such areas as computer science, engineering design, chemistry, physics, biology, medicine, psychology, art, and insight for the blind. With touch communication we can feel things never felt or seen before and perceive spatial relationships not otherwise possible. We can thereby create a more sensitive awareness and understanding of natural phenomena in three-dimensional space, phenomena involving forces and torques for which visual representation is often inappropriate or impossible.