Showing papers by "University of Houston published in 1997"
TL;DR: The authors examined differences between entrepreneurs and managers in large organizations with respect to two biases and heuristics: overconfidence (overestimating the probability of being right) and representativeness (the tendency to overgeneralize from a few characteristics or observations).
2,505 citations
TL;DR: This paper found more evidence against the unit-root hypothesis than Zivot and Andrews, but less than Perron, who argued that the observed behavior may indicate failure to account for structural change.
Abstract: Ever since Nelson and Plosser (1982) found evidence in favor of the unit-root hypothesis for 13 long-term annual macro series, observed unit-root behavior has been equated with persistence in the economy. Perron (1989) questioned this interpretation, arguing instead that the “observed” behavior may indicate failure to account for structural change. Zivot and Andrews (1992) restored confidence in the unit-root hypothesis by incorporating an endogenous break point into the specification. By allowing for the possibility of two endogenous break points, we find more evidence against the unit-root hypothesis than Zivot and Andrews, but less than Perron.
1,508 citations
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TL;DR: The results indicate that helping behavior and sportsmanship had significant effects on performance quantity and that helpingbehavior had a significant impact on performance quality, but civic virtue had no effect on either performance measure.
Abstract: Despite the widespread interest in the topic of organizational citizenship behaviors (OCBs), little empirical research has tested the fundamental assumption that these forms of behavior improve the effectiveness of work groups or organizations in which they are exhibited. In the present study, the effects of OCBs on the quantity and quality of the performance of 218 people working in 40 machine crews in a paper mill located in the Northeastern United States were examined. The results indicate that helping behavior and sportsmanship had significant effects on performance quantity and that helping behavior had a significant impact on performance quality. However; civic virtue had no effect on either performance measure.
1,373 citations
TL;DR: In this article, the authors provide a geometrical argument as to why the Pareto curve is convex, and show that this is not the case for all parts of the set.
Abstract: A standard technique for generating the Pareto set in multicriteria optimization problems is to minimize (convex) weighted sums of the different objectives for various different settings of the weights. However, it is well-known that this method succeeds in getting points from all parts of the Pareto set only when the Pareto curve is convex. This article provides a geometrical argument as to why this is the case.
1,052 citations
TL;DR: The predictive validity of two measurement methods of self-image congruence (traditional versus new) were compared in six studies involving different consumer populations, products, consumption settings, and dependent variables (brand preference, preference for product form, consumer satisfaction/dissatisfaction, brand attitude, and program choice).
Abstract: The predictive validity of two measurement methods of self-image congruence—traditional versus new—were compared in six studies involving different consumer populations, products, consumption settings, and dependent variables (brand preference, preference for product form, consumer satisfaction/dissatisfaction, brand attitude, and program choice). The traditional method is based on tapping the subject’s perception of product-user image and the subject’s perception of his/her self-image along a predetermined set of image attributes and adding the self-congruity scores across all image dimensions. Three problems were identified and discussed in relation to the traditional method: (1) the use of discrepancy scores, (2) the possible use of irrelevant images, and (3) the use of the compensatory decision rule. The new method is based on tapping the psychological experience of self-congruity directly and globally. The findings demonstrated the predictive validity of the new method over and beyond the traditional method.
960 citations
TL;DR: Although many approaches and techniques exist to approach different versions of the static output feedback problem in the control of linear, time-invariant systems, no efficient algorithmic solutions are available.
952 citations
TL;DR: Attitudinal body dissatisfaction, both questionnaire and self-ideal discrepancy measures, produced substantially larger effect sizes than did perceptual size-estimation inaccuracy, which appears unlikely to reflect a more generalized sensory/perceptual deficit.
Abstract: Objective
Although body-image disturbance is among the diagnostic criteria for anorexia nervosa and bulimia nervosa, the nature and extent of this disturbance have not been precisely identified. This is the purpose of this first meta-analysis of extant research on body image and eating disorders. Method: Using contemporary techniques, the meta-analysis systematically examined 66 studies (from 1974 to 1993) of perceptual and attitudinal parameters of body image among anorexics and bulimics relative to control groups. Results: Attitudinal body dissatisfaction, both questionnaire and self-ideal discrepancy measures, produced substantially larger effect sizes than did perceptual size-estimation inaccuracy. Body dissatisfaction measures, whether global or weight/shape related, differentiated bulimic and anorexic groups (with bulimics having more dissatisfaction), whereas perceptual distortion indices did not. Somewhat larger effects occurred with whole-body than with body-part size-estimation assessments. Size distortion among patients with eating disorders appears unlikely to reflect a more generalized sensory/perceptual deficit. Discussion: Scientific, conceptual, and clinical implications of these findings are delineated. © 1997 Wiley-Liss, Inc. Int J Eat Disord 22: 107–125, 1997.
824 citations
TL;DR: It is shown that fully interpolatory higher order vector basis functions of the Nedelec type are defined in a unified and consistent manner for the most common element shapes and sample numerical results confirm the faster convergence of the higher order functions.
Abstract: Low-order vector basis functions compatible with the Nedelec (1980) representations are widely used for electromagnetic field problems. Higher-order functions are receiving wider application, but their development is hampered by the complex procedures used to generate them and lack of a consistent notation for both elements and bases. In this paper, fully interpolatory higher order vector basis functions of the Nedelec type are defined in a unified and consistent manner for the most common element shapes. It is shown that these functions can be obtained as the product of zeroth-order Nedelec representations and interpolatory polynomials with specially arranged arrays of interpolation points. The completeness properties of the vector functions are discussed, and expressions for the vector functions of arbitrary polynomial order are presented. Sample numerical results confirm the faster convergence of the higher order functions.
648 citations
TL;DR: In this paper, Jeong et al. used a conditional sampling scheme to extract the entire extent of dominant vortical structures near the wall in a numerically simulated turbulent channel flow.
Abstract: Coherent structures (CS) near the wall (i.e. y + ≤ 60) in a numerically simulated turbulent channel flow are educed using a conditional sampling scheme which extracts the entire extent of dominant vortical structures. Such structures are detected from the instantaneous flow field using our newly developed vortex definition (Jeong & Hussain 1995) - a region of negative λ 2, the second largest eigenvalue of the tensor SikSkj + ΩikΩkj - which accurately captures the structure details (unlike velocity-, vorticity- or pressure-based eduction). Extensive testing has shown that λ 2 correctly captures vortical structures, even in the presence of the strong shear occurring near the wall of a boundary layer. We have shown that the dominant near-wall educed (i.e. ensemble averaged after proper alignment) CS are highly elongated quasi-streamwise vortices; the CS are inclined 9° in the vertical (x, y)-plane and tilted ±4° in the horizontal (x, z)-plane. The vortices of alternating sign overlap in x as a staggered array; there is no indication near the wall of hairpin vortices, not only in the educed data but also in instantaneous fields. Our model of the CS array reproduces nearly all experimentally observed events reported in the literature, such as VITA, Reynolds stress distribution, wall pressure variation, elongated low-speed streaks, spanwise shear, etc. In particular, a phase difference (in space) between streamwise and normal velocity fluctuations created by CS advection causes Q4 ('sweep’) events to dominate Q2 ('ejection’) and also creates counter-gradient Reynolds stresses (such as Ql and Q3 events) above and below the CS. We also show that these effects are adequately modelled by half of a Batchelor's dipole embedded in (and decoupled from) a background shear U(y). The CS tilting (in the (x, z)-plane) is found to be responsible for sustaining CS through redistribution of streamwise turbulent kinetic energy to normal and spanwise components via coherent pressure-strain effects.
647 citations
TL;DR: In this paper, the authors investigate long-run purchasing power parity by testing for unit roots in real exchange rates of industrial countries under the current float, and find that accounting for serial correlation considerably weakens the evidence against the unit root null hypothesis.
612 citations
TL;DR: This work presents examples from the literature to illustrate how sperm competition and female choice of sperm can enable polyandrous females to minimize the risk of fertilization by genetically–incompatible sperm.
Abstract: Fundamental to the recentlyproposed hypothesis that females mate with more than one male as a hedge against genetic incompatibility is the premise that mechanisms are available to polyandrous femal...
TL;DR: In this paper, the authors examined the relation between correlation and variance in a conditional time and state varying framework and found that the correlations between the U.S. and other world markets are on average 2 to 3.5 times higher when the market is in a high variance state as compared to a low variance regime.
Abstract: Several papers have documented the fact that correlations across major stock markets are higher when markets are more volatile - this is done by comparing unconditional correlations over sub-periods or by using conditional correlations that are time varying. In this paper we examine the relation between correlation and variance in a conditional time and state varying framework. We use a switching ARCH (SWARCH) technique that does two things. One, it enables us to model variance as state varying. Two, a bivariate SWARCH model allows us to go from conditional variance to state varying covariances and correlations and hence test for differences in correlations across variance regimes. We find that the correlations between the U.S. and other world markets are on average 2 to 3.5 times higher when the U.S. market is in a high variance state as compared to a low variance regime. We also find that, compared to a GARCH framework, the portfolio choices resulting from our SWARCH model lead to higher Sharpe ratios.
TL;DR: In this article, the authors reviewed the research literature in order to describe and evaluate the many ways interviews can be structured and identified fifteen components of structure that may enhance either the content of the interview or the evaluation process in the interview.
Abstract: Virtually every previous review has concluded that structuring the selection interview improves its psychometric properties. This paper reviews the research literature in order to describe and evaluate the many ways interviews can be structured. Fifteen components of structure are identified that may enhance either the content of the interview or the evaluation process in the interview. Each component is explained in terms of its various operationalizations in the literature. Then, each component is critiqued in terms of its impact on numerous forms of reliability, validity, and user reactions. Finally, recommendations for research and practice are presented. It is concluded that interviews can be easily enhanced by using some of the many possible components of structure, and the improvement of this popular selection procedure should be a high priority for future research and practice.
TL;DR: In this article, the authors argue that large variations in stock prices happen with sufficient frequency to raise doubts about existing models, which all fail to account for non-Gaussian statistics, and argue that the large variations may be due to a crowd effect, where agents imitate each other's behavior.
Abstract: Large variations in stock prices happen with sufficient frequency to raise doubts about existing models, which all fail to account for non-Gaussian statistics. We construct simple models of a stock market, and argue that the large variations may be due to a crowd effect, where agents imitate each other's behavior. The variations over different time scales can be related to each other in a systematic way, similar to the Levy stable distribution proposed by Mandelbrot to describe real market indices. In the simplest least realistic case, exact results for the statistics of the variations are derived by mapping onto a model of diffusing and annihilating particles, which has been solved by quantum field theory methods. When the agents imitate each other and respond to recent market volatility, different scaling behavior is obtained. In this case, the statistics of price variations is consistent with empirical observations. The interplay between “rational” traders whose behavior is derived from fundamental analysis of the stock, including dividends, and “noise traders”, whose behavior is governed solely by studying the market dynamics and the behavior of other traders, is investigated. When the relative number of rational traders is small, “bubbles” often occur, where the market price moves outside the range justified by fundamental market analysis. When the number of rational traders is larger, the market price is generally locked within the price range they define.
TL;DR: In this article, three compounds were obtained from the reactions of Co(NCS)2 with pyrazine and 4,4‘-bipyridine in different solvents.
Abstract: Three compounds were obtained from the reactions of Co(NCS)2 with pyrazine and 4,4‘-bipyridine in different solvents: Co(NCS)2(pyz)2 (1) has a 2D sheet structure, monoclinic, C2/m, a = 10.039(2) A, b = 10.382(2) A, c = 7.190(1) A, β = 118.64(1)°, Z = 2; Co(NCS)2(H2O)2(4,4‘-bipy)·4,4‘-bipy (2) has linear Co−bipy−Co chains connected by hydrogen bonds between H2O and noncoordinated 4,4‘-bipy molecules to form stair type sheets, triclinic, P1, a = 7.450(1) A, b = 9.020(1) A, c = 10.122(1) A, α = 107.74(1)°, β = 104.02(1)°, γ = 97.16(1)°, Z = 1; Co(NCS)2(4,4‘-bipy)2·2(CH3CH2)2O (3) has ether molecules intercalated between layers formed by Co(NCS)2 and coordinated 4,4‘-bipyridine ligands, monoclinic, P2/c, a = 11.483(2) A, b = 11.397(3) A, c = 13.609(1) A, β = 107.55(1)°, Z = 2. Compounds 2 and 3 thermally decompose to form the same products. The identities of the decomposition products are discussed.
TL;DR: In this paper, the authors provide an overview of the research extended in the areas of associations' location choice and participation decision-making variables of the attendees and propose two models to address the interaction and interrelationships among associations, host locations, and attendees.
TL;DR: The proposed hybrid learning scheme provides a framework for incorporating existing algorithms in the training of GRBF networks, which include unsupervised algorithms for clustering and learning vector quantization, as well as learning algorithms for training single-layer linear neural networks.
Abstract: This paper proposes a framework for constructing and training radial basis function (RBF) neural networks. The proposed growing radial basis function (GRBF) network begins with a small number of prototypes, which determine the locations of radial basis functions. In the process of training, the GRBF network gross by splitting one of the prototypes at each growing cycle. Two splitting criteria are proposed to determine which prototype to split in each growing cycle. The proposed hybrid learning scheme provides a framework for incorporating existing algorithms in the training of GRBF networks. These include unsupervised algorithms for clustering and learning vector quantization, as well as learning algorithms for training single-layer linear neural networks. A supervised learning scheme based on the minimization of the localized class-conditional variance is also proposed and tested. GRBF neural networks are evaluated and tested on a variety of data sets with very satisfactory results.
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28 Jul 1997TL;DR: In this paper, the masonry theory of masonry and its application in the construction of towers and bells are discussed, as well as the structural elements of a masonry vault.
Abstract: Preface 1. Introduction 2. Structural theory of masonry 3. Domes 4. The masonry vault 5. Some structural elements 6. Towers and bells 7. Spires 8. Some historical notes Bibliography Index.
TL;DR: Individual growth curve analyses showed that measures of the preinjury family environment consistently predicted both the level of cognitive and behavioral functioning at 12 months postinjury and the rate of intraindividual change during the 12-month follow-up period, even after taking into account group membership and injury severity.
Abstract: Previous studies of childhood traumatic brain injury (TBI) have emphasized injury-related variables rather than environmental factors as predictors of recovery. We addressed this concern using data collected during a prospective study of children with either TBI or orthopedic injuries (OI) and their families. Participants included 53 children with severe TBI, 56 with moderate TBI, and 80 with OI, all from 6 to 12 years of age at the time of injury. Measures of the preinjury family environment were collected shortly after the injury (baseline). Child cognitive and behavioral outcomes were assessed at baseline and at 6- and 12-month follow-ups. Individual growth curve analyses showed that measures of the preinjury family environment consistently predicted both the level of cognitive and behavioral functioning at 12 months postinjury and the rate of intraindividual change during the 12-month follow-up period, even after taking into account group membership and injury severity. In some cases, the preinjury family environment was a significant moderator of the effect of TBI, buffering its impact in high-functioning families and exacerbating it in low-functioning families. Thus, preinjury environmental factors predict recovery following TBI in children, even after accounting for injury-related variables.
TL;DR: It is demonstrated that a second IL‐1R‐related Drosophila protein, 18‐Wheeler (18W), is a critical component of the humoral immune response and expression is induced in response to infection.
Abstract: Mammals and insects employ similar Rel/NF-kappaB signaling cascades in their humoral immune responses. The mammalian interleukin-1 type I receptor (IL-1R) is one way of activating this cascade. The Drosophila Toll protein, whose cytoplasmic domain shows striking similarity to that of the IL-1R, acts in the humoral antimicrobial response. Here we demonstrate that a second IL-1R-related Drosophila protein, 18-Wheeler (18W), is a critical component of the humoral immune response. 18-wheeler is expressed in the larval fat body, the primary organ of antimicrobial peptide synthesis. In the absence of the 18W receptor, larvae are more susceptible to bacterial infection. Nuclear translocation of the Rel protein Dorsal-like immunity factor (Dif) is inhibited, though nuclear translocation of another Rel protein, Dorsal, is unaffected. Induction of several antibacterial genes is reduced following infection, relative to wild-type: attacin is reduced by 95%, cecropin by 65% and diptericin by 12%. Finally, 18-wheeler (18w) expression is induced in response to infection and, in addition to the receptor form, four immune-specific transcripts and proteins are produced.
TL;DR: The authors examined the effect of economic perceptions on vote choice and found that the cross-sectional effects of the economy on voter choice have been substantially over-estimated and that economic perceptions are themselves structured by vote choice.
Abstract: Much previous research shows that variation in vote choice closely follows variation in economic perceptions over time. A number of scholars argue that the pattern is rooted in cross-sectional effects and have found apparent evidence of such effects. However, most of these studies do not take into account the possibility that economic perceptions are themselves structured by vote choice, which poses potentially serious implications. We begin to address this endogeneity, focusing specifically on Lewis-Beck's (1988) analysis of economic voting. The results suggest that the cross-sectional effects of the economy on vote choice have been substantially overstated.
TL;DR: In this paper, the surface composition, termination, and structure of the Al 2 O 3 {0001}-(1 × 1) surface have been determined through the use of time-of-flight scattering and recoiling spectrometry (TOF-SARS), low energy electron diffraction (LEED), and classical ion trajectory simulations.
TL;DR: In this paper, necessary and sufficient conditions for the existence of a solution to the continuous-time and discrete-time reduced-order H/sub/spl infin// and L/sub 2/L/sub 1/spl ∆ ) filtering problems are derived in terms of linear matrix inequalities and a coupling nonconvex matrix rank constraint.
Abstract: Necessary and sufficient conditions are derived for the existence of a solution to the continuous-time and discrete-time reduced-order H/sub /spl infin// and L/sub 2/-L/sub /spl infin// filtering problems. These conditions are expressed in terms of linear matrix inequalities (LMIs) and a coupling nonconvex matrix rank constraint. Convex LMI problems are obtained for the full-order and the zeroth-order filtering. An explicit parametrization of all reduced-order filters that correspond to a feasible solution is derived in terms of a contractive matrix, and iterative algorithms are proposed to solve the reduced-order filtering problems using alternating projections.
TL;DR: In this paper, a charge-transfer origin (λCT) analysis of the colored solutions revealed their charge transfer origin and provided quantitative information of the intermolecular association in the form of the KDA and eCT values for the formation and visualization, respectively, of different [D,A] complexes.
Abstract: Molecular association of various aromatic hydrocarbons (D, including sterically hindered donors) with a representative group of diverse acceptors (A = quinone, trinitrobenzene, tetracyanoethylene, tropylium, tetranitromethane, and nitrosonium) is visually apparent in solution by the spontaneous appearance of distinctive colors. Spectral (UV−vis) analyses of the colored solutions reveal their charge-transfer origin (λCT), and they provide quantitative information of the intermolecular association in the form of the KDA and eCT values for the formation and visualization, respectively, of different [D,A] complexes. Importantly, such measurements establish charge-transfer absorption to be a sensitive analytical tool for evaluating the steric inhibition of donor−acceptor association. For example, the steric differences among various hindered aromatic donors in their association with quinone are readily dramatized in their distinctive charge-transfer (color) absorptions and verified by X-ray crystallography of ...
TL;DR: Using sequential trend break and panel data models, this paper investigated the unit root hypothesis for the inflation rates of thirteen OECD countries and found evidence of stationarity in only four of the thirteen countries.
Abstract: SUMMARY Using sequential trend break and panel data models, we investigate the unit root hypothesis for the inflation rates of thirteen OECD countries. With individual country tests, we find evidence of stationarity in only four of the thirteen countries. The results are more striking with the panel data model. We can strongly reject the unit root hypothesis both for a panel of all thirteen countries and for a number of smaller panels consisting of as few as three countries. The non-rejection of the unit root hypothesis for inflation is very fragile to even a small amount of cross-section variation. #1997 John Wiley & Sons, Ltd.
TL;DR: Overall, tabu search tends to give the most robust results closely followed by simulated annealing, and genetic algorithms do not generally perform well for these types of problems, except when very few candidate solutions may be evaluated because of large computing requirements.
TL;DR: In this paper, the authors test six restrictions in the context of common ratio effect data for a general class of theories of risky choice, and two restrictions, one for aggregate and one for individual data, are supported.
Abstract: Probabilistic choices or ‘choice errors’ may play an important supporting role in shaping observed risky choices, and a variety of restrictions on such choice probabilities play the role of identifying restrictions in empirical decision research. We test six restrictions in the context of common ratio effect data for a general class of theories of risky choice. Two restrictions, one for aggregate and one for individual data, are supported. But none of the heterogeneity restrictions that make the aggregate data model powerful survive scrutiny; nor do estimable parametric versions of the individual data model. There is room for new stochastic identifying restrictions in empirical decision research.
TL;DR: In this paper, the authors examined the impact of "expectations" on service quality perceptions in the Hong Kong hotel industry which involved cross-cultural samples and found that significant expectations differences exist between cultural groups and that expectation did not improve the validity of SERVQUAL.
TL;DR: In this article, a contingency framework for the mode of entry decision which accomodates alternative decision strategies is presented, and an outcome of the cybernetic strategy is an hierarchical model for the Mode of Entry decision.
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TL;DR: In this paper, the authors provide a unified framework to simultaneously investigate asymmetric volatility at the firm and the market level and examine two potential explanations of the asymmetry: leverage effects and time-varying risk premiums.
Abstract: It appears that volatility in equity markets is asymmetric: returns and conditional volatility are negatively correlated. We provide a unified framework to simultaneously investigate asymmetric volatility at the firm and the market level and to examine two potential explanations of the asymmetry: leverage effects and time-varying risk premiums. Our empirical application uses the market portfolio and portfolios with different leverage constructed from Nikkei 225 stocks, extending the empirical evidence on asymmetry to Japanese stocks. Although volatility asymmetry is present and significant at the market and the portfolio levels, its source differs across portfolios. We find that it is important to include leverage ratios in the volatility dynamics but that their economic effects are mostly dwarfed by the volatility feedback mechanism. Volatility feedback is enhanced by a phenomenon that we term covariance asymmetry: conditional covariances with the market increase only significantly following negative market news. We do not find significant asymmetries in conditional betas.