Showing papers by "University of Illinois at Urbana–Champaign published in 1984"

Subjective Well-Being

Abstract: The literature on subjective well-being (SWB), including happiness, life satisfaction, and positive affect, is reviewed in three areas: measurement, causal factors, and theory. Psychometric data on single-item and multi-item subjective well-being scales are presented, and the measures are compared. Measuring various components of subjective well-being is discussed. In terms of causal influences, research findings on the demographic correlates of SWB are evaluated, as well as the findings on other influences such as health, social contact, activity, and personality. A number of theoretical approaches to happiness are presented and discussed: telic theories, associationistic models, activity theories, judgment approaches, and top-down versus bottom-up conceptions.

Subjective Well-being

Abstract: The literature on subjective well-being (SWB), including happiness, life satisfaction, and positive affect, is reviewed in three areas: measurement, causal factors, and theory. Psychometric data on single-item and multi-item subjective well-being scales are presented, and the measures are compared. Measuring various components of subjective well-being is discussed. In terms of causal influences, research findings on the demographic correlates of SWB are evaluated, as well as the findings on other influences such as health, social contact, activity, and personality. A number of theoretical approaches to happiness are presented and discussed: telic theories, associationistic models, activity theories, judgment approaches, and top-down versus bottom-up conceptions.

Algorithm-Based Fault Tolerance for Matrix Operations

Abstract: The rapid progress in VLSI technology has reduced the cost of hardware, allowing multiple copies of low-cost processors to provide a large amount of computational capability for a small cost. In addition to achieving high performance, high reliability is also important to ensure that the results of long computations are valid. This paper proposes a novel system-level method of achieving high reliability, called algorithm-based fault tolerance. The technique encodes data at a high level, and algorithms are designed to operate on encoded data and produce encoded output data. The computation tasks within an algorithm are appropriately distributed among multiple computation units for fault tolerance. The technique is applied to matrix compomations which form the heart of many computation-intensive tasks. Algorithm-based fault tolerance schemes are proposed to detect and correct errors when matrix operations such as addition, multiplication, scalar product, LU-decomposition, and transposition are performed using multiple processor systems. The method proposed can detect and correct any failure within a single processor in a multiple processor system. The number of processors needed to just detect errors in matrix multiplication is also studied.

A Nation at Risk

Abstract: † United States Department of Education, National Commission on Excellence in Education, A Nation at Risk (us Government Printing Office, Washington, DC, 1983). Stock No. 065-000-00177-2, $4·50.

Orientation Behavior of Fibers in Concentrated Suspensions

Abstract: A mathematical model is developed to predict the orientation distribution function of rigid fibers in concentrated suspensions. The model contains a phenomenological term to account for interactions between fibers. Predictions of the model are tested against experiments in simple shear flow, using suspensions of nylon monofilaments in silicone oil. The results compare favorably for steady-state distributions, though the theory predicts a more rapid approach to steady state than actually occurs. The model predicts, and experiments show, that fiber orientation is not reversible when the flow is reversed. The model is useful for predicting the effects of processing on fiber orienta tion in short fiber composites.

Cognitive simplification processes in strategic decision‐making

Abstract: Strategic decision-making can be viewed as a special kind of decision-making under uncertainty. Such decision-making involves the activities of goal formulation, problem identification, alternatives generation, and evaluation/selection. Researchers in cognitive psychology and behavioural decision theory have identified a number of cognitive simplification processes which may affect the way decision-makers perform these tasks. Within this paper, the research on these processes is summarized and their possible effects on strategic decision-making are discussed. Implications for future research in this area are also drawn.

Uniqueness and Estimation of Three-Dimensional Motion Parameters of Rigid Objects with Curved Surfaces

Abstract: Two main results are established in this paper. First, we show that seven point correspondences are sufficient to uniquely determine from two perspective views the three-dimensional motion parameters (within a scale factor for the translations) of a rigid object with curved surfaces. The seven points should not be traversed by two planes with one plane containing the origin, nor by a cone containing the origin. Second, a set of ``essential parameters'' are introduced which uniquely determine the motion parameters up to a scale factor for the translations, and can be estimated by solving a set of linear equations which are derived from the correspondences of eight image points. The actual motion parameters can subsequently be determined by computing the singular value decomposition (SVD) of a 3×3 matrix containing the essential parameters.

Factor analysis and construct validity of the Narcissistic Personality Inventory.

Abstract: Three studies are reported which provide evidence for the validity of the Narcissistic Personality Inventory (NPI). Factor analysis of the NPI in Study 1 revealed four factors which were labelled: Exploitativeness/Entitlement, Leadership/Authority, Superiority/Arrogance, and Self-absorption/Self-admiration. In Study 2, scores on the NPI were correlated with basic dimensions of personality, and with relevant self-variables. Narcissism scores were positively related to dominance, exhibitionism, extraversion, self-esteem, and self-monitoring, among others; and negatively related to abasement, deference, and social anxiety, among others. Correlations between the NPI factors and personality variables are also examined. In Study 3, peer ratings of narcissism were obtained and it was found that these were strongly related to scores on the NPI. Taken together, the three studies provide considerable evidence for the construct validity of the NPI, and avenues for future research are suggested.

Energy and the u.s. Economy: a biophysical perspective.

Abstract: A series of hypotheses is presented about the relation of national energy use to national economic activity (both time series and cross-sectional) which offer a different perspective from standard economics for the assessment of historical and current economic events. The analysis incorporates nearly 100 years of time series data and 3 years of cross-sectional data on 87 sectors of the United States economy. Gross national product, labor productivity, and price levels are all correlated closely with various aspects of energy use, and these correlations are improved when corrections are made for energy quality. A large portion of the apparent increase in U.S. energy efficiency has been due to our ability to expand the relative use of high-quality fuels such as petroleum and electricity, and also to relative shifts in fuel use between sectors of the economy. The concept of energy return on investment is introduced as a major driving force in our economy, and data are provided which show a marked decline in energy return on investment for all our principal fuels in recent decades. Future economic growth will depend largely on the net energy yield of alternative fuel sources, and some standard economic models may need to be modified to account for the biophysical constraints on human economic activity.

Simpatia as a Cultural Script of Hispanics.

Abstract: : A cultural script is a pattern of social interaction which is characteristic of a particular cultural group. Simpatia, and its component harmony, or the emphasis on positive behaviors in positive situations (e.g., complimenting somebody who has done a good job) and the de-emphasis of negative behaviors in negative situations (e.g., criticising) may be a Hispanic cultural script. Lower status individuals are not supposed to show aggression even when their rights are taken away. The data indicate that Hispanic recruits expect more positive behaviors in positive social situations and de-emphasize the appropriateness of negative behaviors in situations of conflict, particularly when the actor is of lower status. The implications of these findings for the Navy is that Hispanics are likely to have higher levels of expectations concerning the appropriateness of positive behaviors (e.g., receiving a compliment if they do a good job) than Mainstream recruits. Thus, they will feel underrewarded in situations where they do a good job. Conversely, they will expect less expression of criticism from lower status individuals, and therefore even mild criticism from such individuals might be seen as extreme criticism. (Author)

The CO2/O 2 specificity of ribulose 1,5-bisphosphate carboxylase/oxygenase : Dependence on ribulosebisphosphate concentration, pH and temperature.

Abstract: The substrate specificity factor, VcKo/VoKc, of spinach (Spinacia oleracea L.) ribulose 1,5-bisphosphate carboxylase/oxygenase was determined at ribulosebisphosphate concentrations between 0.63 and 200 μM, at pH values between 7.4 and 8.9, and at temperatures in the range of 5° C to 40° C. The CO2/O2 specificity was the same at all ribulosebisphosphate concentrations and largely independent of pH. With increasing temperature, the specificity decreased from values of about 160 at 5° C to about 50 at 40° C. The primary effects of temperature were on Kc [Km(CO2)] and Vc [Vmax (CO2)], which increased by factors of about 10 and 20, respectively, over the temperature range examined. In contrast, Ko [Ki (O2)] was unchanged and Vo [Vmax (O2)] increased by a factor of 5 over these temperatures. The CO2 compensation concentrations (Γ) were calculated from specificity values obtained at temperatures between 5° C and 40° C, and were compared with literature values of Γ. Quantitative agreement was found for the calculated and measured Γ values. The observations reported here indicate that the temperature response of ribulose 1,5-bisphosphate carboxylase/oxygenase kinetic parameters accounts for two-thirds of the temperature dependence of the photorespiration/photosynthesis ratio in C3 plants, with the remaining one-third the consequence of differential temperature effects on the solubilities of CO2 and O2.

On the Dependence of P300 Latency on Stimulus Evaluation Processes

Abstract: McCarthy and Donchin (1981) found that the latency of a late positive component of the event-related potential (ERP) was influenced by the presence of noise in a stimulus matrix but not by the compatibility between the stimulus presented and the response required They concluded that this component is a P300 and that its latency was influenced by stimulus evaluation but not by response selection processes The present experiments were designed to confirm that the component identified by McCarthy and Donchin was indeed a P300 and to determine if its latency varies systematically with increases in stimulus evaluation time produced by graded changes in noise level In Experiment 1, subjects performed a standard oddball task in which they were required to count the rarer of two stimuli (the words RIGHT or LEFT) which were, or were not, embedded in a noise matrix (characters from the alphabet) The positive component of the ERP, whose amplitude was larger for rare target stimuli, was labeled a P300, and the latency of this component was longer when the stimuli were embedded in noise In Experiment 2, subjects performed a choice reaction time task Following the procedures used by McCarthy and Donchin, stimulus words RIGHT and LEFT required right or left hand responses depending on the presence of a cue word SAME or OPPOSITE which preceded the stimulus Stimulus words were presented in four different degrees of noise, the levels of which were manipulated by varying the set size of the alphabetic characters which could surround the stimulus words Reaction time increased both with noise (by 325 ms) and as a function of stimulus-response incompatibility (by 127 ms) In contrast, P300 latency increased substantially with noise (by 200 ms) but, to a much lesser extent (by 14 ms), with response incompatibility These results indicate that the P300 is sensitive to the ease with which a target stimulus can be discriminated from noise They confirm that P300 latency can be used as a measure of the timing of stimulus evaluation processes that is relatively independent of response selection and execution

Destabilizing Hybridization, General-Purpose Genotypes and Geographic Parthenogenesis

Abstract: The ecological and genetic correlates of parthenogenesis are clarified by focusing upon two of the major challenges that confront a newly arisen parthenogen: the genetic disruption that results from backcrosses with sexual relatives, and the evolution of a highly generalized genotype. Both of these factors have been ignored in previous theories of the evolution of reproductive systems. Yet, the geographic ranges, ecological characteristics, elevated ploidy levels, and hybrid origins of many parthenogens, as well as the widespread suppression of recombination in automicts, are consistent with expectations derived from the destabilizing hybridization and general-purpose genotype hypotheses. Whereas the support for these hypotheses is broad, much of the evidence is circumstantial; experimental tests would allow an evaluation of the proposed hypotheses and the more traditional alternatives based on differential colonization, competitive, and coevolutionary abilities. An appreciation of the stringent requireme...

Concepts and Concept Formation

Abstract: categories. That is, since cue validity is the probability of being in some category given some property, this probability will increase (or at worst not decrease) as the size of the category increases (e.g. the probability of being an animal given the property of flying is greater than the probability of bird given flying, since there must be more animals that fly than birds that fly).6 The idea that cohesive categories maximize the probability of particular properties given the category fares no better. In this case, the most specific categories will always be picked out. Medin (1982) has analyzed a variety of formal measures of category cohe­ siveness and pointed out problems with all of them. For example, one possible principle is to have concepts such that they minimize the similarity between contrasting categories; but minimizing between-category similarity will always lead one to sort a set of n objects into exactly two categories. Similarly, functions based on maximizing within-category similarity while minimizing between-category similarity lead to a variety of problems and counterintuitive expectations about when to accept new members into existent categories versus when to set up new categories. At a less formal but still abstract level, Sternberg (1982) has tried to translate some of Goodman's (e.g. 1983) ideas about induction into possible constraints on natural concepts. Sternberg suggests that the apparent naturalness of a concept increases with the familiarity of the concept (where familiarity is related to Goodman's notion of entrenchment), and decreases with the number of transformations specified in the concept (e.g. aging specifies certain trans­

Signal Versus Noise in the Southern Oscillation

Abstract: The utility of a simple index for monitoring the Southern Oscillation signal is explored in detail. Based upon sea level pressure data at the two stations Tahiti (T) and Darwin (D), an optimal index, in the sense that it combines the Southern Oscillation variance into one series is the combination [Tn + Dn] where the subscript n denotes normalization by the overall standard deviation of each series. A direct measure of the noise due to small-scale or transient phenomena that are not a part of the large-scale coherent Southern Oscillation fluctuations is the index [Tn + Dn]. It is recommended that this index of noise also should be monitored in order to determine the representativeness of the Southern Oscillation index. The signal-to-noise ratio is shown to depend upon the cross correlation between Darwin and Tahiti, and can be increased by applying weighted moving average low-pass filters to the data. Monthly data exhibit a signal-to-noise ratio, defined as the ratio of the standard deviations, o...

A low-overhead coherence solution for multiprocessors with private cache memories

Abstract: This paper presents a cache coherence solution for multiprocessors organized around a single time-shared bus. The solution aims at reducing bus traffic and hence bus wait time. This in turn increases the overall processor utilization. Unlike most traditional high-performance coherence solutions, this solution does not use any global tables. Furthermore, this coherence scheme is modular and easily extensible, requiring no modification of cache modules to add more processors to a system. The performance of this scheme is evaluated by using an approximate analysis method. It is shown that the performance of this scheme is closely tied with the miss ratio and the amount of sharing between processors.

Pathogen mortality of tropical tree seedlings: experimental studies of the effects of dispersal distance, seedling density, and light conditions

Abstract: We present results of two experiments designed to identify the relative importance of dispersal distance, seedling density, and light conditions on pathogen-caused mortality of tropical tree seedlings. The field experiment on Barro Colorado Island, Panama, demonstrated that both an increase in dispersal distance and a decrease in seedling density reduce levels of damping-off disease among seedlings of Platypodium elegans, and that there is an interaction between the two factors. The results indicated significant variation among sites in pathogen activity and suggested that seedlings are more vulnerable to disease when establishing around their parent tree than around other conspecific trees.The second experiment in a screened enclosure used potted seedlings of 18 wind-dispersed tree species exposed to two levels of sunlight and seedling density. The results indicated that environmental conditions similar to those in light-gaps significantly reduce pathogen activity. They also confirmed that high seedling density increases disease levels, especially under shaded conditions.Seedlings of 16 of the 18 species experienced pathogencaused mortality, but in widely varying amounts. Seed weight was not a good predictor of a species' vulnerability to pathogens. Adult wood density, an indicator of growth rate and successional status, was inversely correlated with a species' vulnerability to pathogens. Fast-growing, colonizing species, whose seedlings require light-gaps, lacked strong resistance to seedling pathogens, relative to slow-growing species able to tolerate shade and escape seedling pathogens. We discuss these results in the context of seed dispersal as a means of escaping from seedling pathogens.

A case of syntactical learning and judgment: How conscious and how abstract?

Abstract: This study examined two possible bases for grammatical judgments following syntactical learning: unconscious representations of a formal grammar, as in Reber's (1976) hypothesis of implicit learning, and conscious rules within informal grammars. Experimental subjects inspected strings generated by a finite-state grammar, viewed either one at a time or all at a time, with implicit or explicit learning instructions. In a transfer test, experimental and control subjects judged the grammatically of grammatical and nongrammatical strings, reporting on every trial the bases for their judgments. In replication of others' results, experimental subjects met the critical test for grammatical abstraction: significantly correct classification of novel strings. We found, however, that reported rules predicted those grammatical judgments without significant residual. Subjects evidently acquired correlated grammars, personal sets of conscious rules, each of limited scope and many of imperfect validity. Those rules themselves were shown to embody abstractions, consciously represented novelty that could account for

Standardization of a Test of Speech Perception in Noise

Abstract: All 10 forms of the test of Speech Perception in Noise (SPIN) were presented to 128 listeners who had some degree of sensorineural hearing loss Presentation of the speech track was at 50 dB above

Person x situation interactions: choice of situations and congruence response models.

Abstract: Two models of Person X Situation interaction were examined. The first model predicts that there is a relation between personality and the situations people naturally choose to be in; the second model predicts that when there is congruence between the situation and personality, a person will experience more positive and less negative affect. These models were investigated by using mood and activity reports gathered on 3,512 occasions sampled randomly from the everyday lives of 42 subjects. Situational dimensions were related to some but not all personality variables investigated. Need for order predicted choice of typical situations and extraversion correlated with time spent recreating socially. However, it was found that individuals did not spend more time in those settings where they experienced more positive emotions nor less time in those situations where they experienced more negative affect. In terms of the affect-congruence model, several predicted relations were found, but several others did not reach significance. The failure of the affect-congruence model to be consistently supported was probably because the affect of individuals was relatively consistent across situations. The present results suggest that although some theoretically meaningful Person X Situation interactions do occur, they are not necessarily strong or easily predictable.

Biomass of Tropical Forests: A New Estimate Based on Forest Volumes

Abstract: Recent assessments of areas of different tropical forest types and their corresponding stand volumes were used to calculate the biomass densities and total biomass of tropical forests. Total biomass was estimated at 205 x 10(9) tons, and weighted biomass densities for undisturbed closed and open broadleaf forests were 176 and 61 tons per hectare, respectively. These values are considerably lower than those previously reported and raise questions about the role of the terrestrial biota in the global carbon budget.

Relationships between Woody Debris and Fish Habitat in a Small Warmwater Stream

Abstract: Abundance of woody debris was manipulated in a small Illinois stream to determine the importance of this material to fish. When a stream reach was divided along midchannel, and debris was added to one side, but removed from the other, fish and benthic invertebrates were usually more abundant on the side with woody debris than on the cleared side. In further experiments during a low-flow year (1980), debris removal was followed by rapid decreases in water depth and occurrence of benthic organic litter, and increases in current velocity and proportion of sand bottom. These changes were less apparent in unaltered reaches during 1980, and in all reaches during 1981, which was a high-flow year. Artificial debris was colonized by many invertebrates, including chironomids, trichopterans, and ephemeropterans. Most large fish (age 2+) avoided reaches without debris, whereas some smaller fish (such as johnny darter) preferred them; preferences for reach treatments were stronger in 1980 than in 1981. The ad...