Showing papers by "Concordia University published in 1990"

The state of the art in online handwriting recognition

Abstract: This survey describes the state of the art of online handwriting recognition during a period of renewed activity in the field. It is based on an extensive review of the literature, including journal articles, conference proceedings, and patents. Online versus offline recognition, digitizer technology, and handwriting properties and recognition problems are discussed. Shape recognition algorithms, preprocessing and postprocessing techniques, experimental systems, and commercial products are examined. >

Focus-on-Form and Corrective Feedback in Communicative Language Teaching: Effects on Second Language Learning

Abstract: The developing oral English of approximately 100 second language learners (four intact classes) was examined in this study. The learners were native speakers of French (aged 10–12 years) who had received a 5-month intensive ESL course in either grade 5 or grade 6 in elementary schools in Quebec. A large corpus of classroom observation data was also analyzed. Substantial between-class differences were found in the accuracy with which students used such English structures as progressive -ing and adjective–noun order in noun phrases. There was some evidence that these differences (which were not correlated with performance on listening comprehension tests) were due to differences in teachers' form-focused instruction. These findings are discussed in terms of current competing views of the role of form-focused instruction in second language learning.

On the meaning of Maslach's three dimensions of burnout

Abstract: The dimensionality of Maslach's (1982) 3 aspects of job burnout--emotional exhaustion, depersonalization, and personal accomplishment--was examined among a sample of supervisors and managers in the human services. A series of confirmatory factor analyses supported the 3-factor model, with the first 2 aspects highly correlated. The 3 aspects were found to be differentially related to other variables reflecting aspects of strain, stress coping, and self-efficacy in predictable and meaningful ways. Implications for better understanding the burnout process are discussed.

Defensive Behavior in Organizations: A Preliminary Model

Abstract: The literature on organizational politics has focused on the proactive promotion of self-interests but has neglected the reactive defense of self-interests. Defensive behaviors are argued to: (1) avoid action, via over-conforming, passing the buck, playing dumb, depersonalizing, smoothing and stretching, and stalling, (2) avoid blame via buffing, playing safe, justifying, scapegoating, misrepresenting, and escalating commitment, and (3) avoid change via resisting change and protecting turf. Organizational antecedents of defensiveness include bureaucratic rationality and various stressors, and individual antecedents include insecurity and anxiety, emotional exhaustion, work alienation, self-monitoring, and low self-efficacy. The effects of defensiveness on the individual, recipients, and organization are discussed, and directions for future research are presented.

Predictors and Consequences of Aggressive Behavior by Community-Based Dementia Patients

Abstract: The frequency, nature, context, and caregivers' reactions to aggressive behavior in 213 dementia patients residing in the community was studied. Aggression was reported in 57.2% of the patients and in 10.6% of the caregivers. Predictors of patient aggression were greater frequency of behavior and memory problems, premorbid aggression, and a more troubled premorbid social relationship between patient and caregiver. Patient aggression predicted the decision to discontinue home care.

Bromocriptine self-administration and bromocriptine-reinstatement of cocaine-trained and heroin-trained lever pressing in rats.

Abstract: Rats were trained to lever press for intravenous cocaine (1.0 mg/kg/injection) and then switched to bromocriptine (0.3, 1.0, or 3.0 mg/kg/injection) on a FR-1 reinforcement schedule. Bromocriptine sustained responding at all three doses; hourly drug intake increased linearly with log-dose. In a second experiment, animals were trained to respond for cocaine (1.0 mg/kg/injection) or heroin (0.1 mg/kg/injection) reinforcement; drug was available for the first 2 h of each daily session; saline was substituted for cocaine or heroin for 5 subsequent hours. One hour into each saline substitution session, an intravenous injection of saline or bromocriptine (0.0, 0.5, 1.0, or 2.0 mg/kg) was given. Bromocriptine reinstated both cocaine-trained and herointrained lever pressing; under these conditions, the drug was most effective in the heroin-trained animals. Reinforcing doses of clonidine (0.0625 and 0.125 mg/kg), methohexital, and nicotine (0.05 and 0.1 mg/kg), and a sub-intoxicating dose of ethanol (2 g/kg) failed to reinstate cocaine-trained responding. These data indicate that bromocriptine has cocaine-like and heroin-like stimulus and reinforcing effects.

Concept Mapping as an Instructional Strategy for High School Biology

Abstract: In this study, concept mapping was assessed as an instructional strategy for use by high school students in learning biology concepts. Concept mapping, which requires learners to plot concepts and their interrelations in a meaningful organizational network, was compared with an established curriculum approach and tested in an interaction with learners of varying verbal ability. The design emphasized external validity. As hypothesized, concept mapping facilitated low-ability learners’ performance, but only on higher level, relational knowledge. The usefulness of the technique was discussed in terms of its ability to individualize and raise the quality of learning with little extra effort or resource costs to the instructional system.

Facilitation of sexual behaviors in the male rat associated with intra-VTA injections of opiates.

Abstract: Male rats were tested for sexual behaviors after bilateral injections of morphine sulfate or dynorphin1–13 into the ventral tegmental area. Both morphine and dynorphin1–13 increased, in a dose-orderly manner, the number of males that mounted, and the display of female-directed behavior. Repeated administration of morphine, but not dynorphin1–13, into the region of the ventral tegmental area increased dopamine (DA) metabolism in the nucleus accumbens, a terminal field of the mesolimbic DA system. These results suggest that activation of elements within the region of the VTA activated by mu and kappa selective agonists are able to facilitate some aspects of sexual behavior, but that only morphine appears to activate dopaminergic elements within the VTA.

Intermodal transportation in north america and the development of inland load centers

Abstract: This paper analyzes the changes that are transforming intermodal transportation in the United States and Canada. Traffic is being concentrated at a relatively small number of inland load centers that serve as regional truck distribution points, and are linked by high volume dedicated train services. Both theoretical and practical implications of the changes are examined, and a range of research questions are presented.

A two switch high performance current regulated DC/AC converter module

Abstract: A high-performance current regulated single-phase DC/AC converter module is proposed in this paper. Its novel features include: a two-switch topology with no "shoot-through" paths, high input to-output voltage gain, low and constant switching frequencies, and practically instantaneous recovery from input or output transients. Moreover, by utilizing an inner filter capacitor current control loop the proposed module can maintain nearly perfect sinusoidal output voltages even with highly nonlinear loads. Furthermore, three-phase operation can be obtained easily by using three of these modules. Finally, the paper includes the analysis and design of the converter power and control circuits and the experimental evaluation of key predicted results. >

Dual moment maps into loop algebras

Abstract: Moment maps are defined from the space of rank-r deformations of a fixedn xn matrixA to the duals $$(\widetilde{g1}(r)^ + )^* , (\widetilde{g1}(n)^ + )^* $$ of the positive half of the loop algebras $$\widetilde{g1}(r),\widetilde{g1}(n)$$ . These maps are shown to give rise to the same invariant manifolds under Hamiltonian flow obtained through the Adler-Kostant-Symes theorem from the rings $$I(\widetilde{g1}(r)^* ),I(\widetilde{g1}(n)^* )$$ of invariant functions. This gives a dual characterization of integrable Hamiltonian systems as isospectral flow in the two loop algebras.

Focused wide-band array processing by spatial resampling

Abstract: The authors present a novel approach for coherently focusing wideband data received by a linear array of sensors. The proposed preprocessing consists of adjusting the spatial sampling rate, or spatially resampling the array outputs as a function of temporal frequency so that broadband sources are aligned in the spatial frequency domain. Spatial resampling has the advantage that it can reduce each wideband source in multigroup multiple-source scenarios to essentially a rank-one representation without preliminary estimates or a priori knowledge of the spatial distribution of the sources. Preliminary simulations performed using a well-known digital interpolation method to implement spatial resampling with the MUSIC spectral estimator have yielded promising results. >

The ALOHA systems in shadowed mobile radio channels with slow or fast fading

Abstract: The influence of receiver capture on the performance of the ALOHA protocol in the presence of shadowing is investigated. The combined effect of Rayleigh fading, log-normal shadowing, and spatial distribution of mobile users is also studied. It is shown that shadowing is similar to fading and near/far phenomena, in that it makes the capture effect possible and provides ALOHA systems with substantial improvements in throughput. It is also confirmed that the superimposed Rayleigh fading, log-normal shadowing, and spatial distribution can further enhance the capture effect, resulting in a ALOHA system with higher throughput. The fast fading effect in ALOHA systems is explored. A very fast fading case is examined which may be considered to be equivalent to interleaving in slow fading. It is found that an ALOHA system under fast fading conditions also benefits from the capture results in higher throughput. >

Complementary algorithms for the recognition of totally unconstrained handwritten numerals

Abstract: Two novel methods for recognizing totally unconstrained handwritten numerals are presented. One classifies samples based on structural features extracted from their skeletons; the other makes use of their contours. Both methods achieve high recognition rates (86.05%, 93.90%) and low substitution rates (2.25%, 1.60%). To take advantage of the inherent complementarity of the two methods, different ways of combining them are studied. It is shown that it is possible to reduce the substitution rate to 0.70%, while the recognition rate remains as high as 92.00% . Furthermore, if reliability is of utmost importance, one can avoid substitutions completely (reliability 100%) and still retain a fairly high recognition rate (84.85%). >

A nontraditional role for water in the cytochrome c oxidase reaction

Abstract: The passage of electrons through cytochrome c oxidase is directly related to the activity of water. Reducing the activity in a system containing reductant, oxygen, and cytochrome oxidase blocks electron transfer between reduced cytochrome a and oxidized cytochrome a3. The extent of the block is directly related to the osmotic pressure of the system, implying that the protein shell of the oxidase acts as a semipermeable membrane that excludes osmotic perturbants but not water. It appears that approximately 10 water molecules must enter and leave the oxidase in order for internal electron transfer to occur.

The leucine regulon of Escherichia coli K-12: a mutation in rblA alters expression of L-leucine-dependent metabolic operons.

Abstract: We have isolated and characterized a highly pleiotropic Escherichia coli mutant affected in the activity of a number of enzymes involved in different metabolic pathways, all of which are regulated by leucine. Selected for its ability to grow with L-serine as sole carbon source, the rbl-1::Tn10 mutant had high levels of L-serine deaminase activity (due to increased transcription of the structural gene) and of another amino acid-degrading enzyme, L-threonine dehydrogenase, and decreased transcription of the operons serA and ilvIH, coding for biosynthetic enzymes. The rbl mutation suppressed the slow growth of a metK mutant, deficient in S-adenosylmethionine synthetase. Furthermore, metK mutants spontaneously accumulated faster-growing rbl-like derivatives, and a commonly used metK strain, RG62, carries such a mutation. The rbl gene is located near 20 min on the E. coli genetic map. All phenotypes of the rbl mutant could be observed in rbl+ strains cultivated in the presence of L-leucine, and exogenous L-leucine had little further effect on the rbl strains. We propose that the rbl gene product is the regulator of a global response to leucine.

The record of magma chamber processes in plagioclase phenocrysts at Thera Volcano, Aegean Volcanic Arc, Greece

Abstract: Lavas and pyroclastic rocks throughout the volcanic stratigraphy of the Tertiary-Quaternary volcanic complex of Thera in the Aegean island arc display inhomogenous plagioclase populations and phenocryst resorption textures, interpreted as indicative of magma mixing. Plagioclase zoning characteristics studied by Nomarski and laser interferometry techniques establish three main categories of plagioclase: (i) inherited plagioclase (nucleated in endmember prior to initial mixing event) (ii) in situ plagioclase (nucleated in mixed or hybrid magma) and (iii) xenocrystic plagioclase. Nomarski contrast images and linearized compositional zoning profiles reveal striking differences between calcic and sodic plagioclases, depending on the composition of the lava in which they are hosted. These differences reflect the contrasting effects of changes in physical-chemical parameters in basic vis-a-vis more acidic melts during magma mixing and/or influx of new magma into the subvolcanic magma chamber, as well as the influence of magma chamber dynamics on plagioclase equilibration. Variations in bulk major and trace element abundances of Thera volcanic products reflect the dominant overprint of crystal fractionation, but decoupling between major and trace element fractionation models and variations in incompatible trace element distributions are all indicative of magma mixing processes, consistent with compositional and textural zoning in plagioclases.

The socialization of sex-differentiated skills and academic performance: a mediational model

Abstract: Using a multifactorial model, sex differences in academic performance were examined in a sample of 347 elementary school children. As expected, girls' academic performance averaged higher than boys'. Path analysis confirmed initial hypotheses that girls' advantage is partially due to their characteristic of greater responsiveness to social cues and compliance with adult direction. This advantage was partially offset in this model by boys' greater visual-spatial skill, which also was a predictor of academic success. Access to stereotypic masculine toys and activities at home was, for both sexes, a predictor of children's visual-spatial ability. As expected, socioeconomic variables, including mothers' occupation and fathers' level of education, also influenced the environmental, social, and cognitive factors predicting academic success. These results indicate that boys' and girls' differential development of specific cognitive and social skills may play an important role in establishing sex differences in academic performance.

Nest temperature: effects on maternal behavior, pup development, and interactions with handling.

Abstract: These studies compared the patterns of mother-young contact under different thermal environments and assessed the implications of the differing patterns of contact for pup development and the dam's behavior. In the first experiment, the warm surface dramatically reduced the total amount of contact time between dams and litters and the dam's food intake, but the effects on the pups were limited to smaller adrenal glands. A replication of the first experiment in which daily weighing and handling of the pups was eliminated produced no differences in development. In a third experiment, during which dams had access to a warm surface outside of the next area and the daily weighing and handling was resumed, the pups showed smaller adrenal glands, lower body temperatures and less thermoregulatory ability. A comparison of results suggests that handling increased the weight of adrenal glands of pups reared under the unmanipulated condition, but not the warm-rearing condition.

Preexposure to foot-shock sensitizes the locomotor response to subsequent systemic morphine and intra-nucleus accumbens amphetamine.

Abstract: The effect of repeated exposure to foot-shock on locomotor activity was examined by testing rats in the shock boxes for one hour following shock exposure. Early in testing activity was elevated relative to the nonshocked control group, between 40-60 min following shock. Over days this period of elevated activity occurred sooner in time and lengthened in duration. When these animals were tested in the absence of shock, those preexposed to shock were more active following either saline or morphine (0.5 and 5.0 mg/kg IP) injections. In a second experiment, elevated spontaneous and morphine-induced activity was also found when rats had been preexposed to shock in boxes distinct from the activity test boxes. In a final experiment, animals preexposed to shock were tested after bilateral infusions of either amphetamine (5 and 10 micrograms/microliters/side) or morphine (5 micrograms/microliters/side) into the nucleus accumbens (NAS). On the amphetamine tests, previously shocked animals were significantly more active than control animals. In contrast, intra-NAS infusions of morphine failed to differentiate between the two groups. These results suggest that repeated mild foot-shock sensitizes the mesolimbic dopamine system by mechanisms similar to those mediating the sensitized behavioral and dopaminergic responses seen following repeated opioid or stimulant administration.

A novel approach to paralleling of power converter units with true redundancy

Abstract: The demand for power supplies with expansion capabilities has prompted interest in modular power converters with built-in features for connection in parallel with two or more other units. The authors describe a novel scheme which offers a given unit frequency and phase synchronization with any number of units operating in parallel. The scheme is based on a master/slave configuration using a rotating priority window which provides random selection of a new master and therefore results in true redundancy. Compared to conventional methods of paralleling, the scheme requires fewer interconnections between individual units and offers increased reliability. System operation and implementation are described in detail, and experimental results are given. >

The Dimensionality of Ratings and Their Use in Personnel Decisions.

Abstract: Teaching is a complex activity with many dimensions, which can be evaluated separately or globally. Global ratings are better for personnel decisions.