Showing papers by "Brigham Young University published in 1988"

Culture and Continuity in Family Firms

Abstract: The culture of the family firm plays an important role in determining the success of the business beyond the first generation.

Inducing rules for expert system development: an example using default and bankruptcy data

Abstract: With rapidly growing interest in the development of knowledge-based computer consulting systems for various problem domains, the difficulties associated with knowledge acquisition have special importance. This paper reports on the results of experiments designed to assess the effectiveness of an inductive algorithm in discovering predictive knowledge structures in financial data. The quality of the results are evaluated by comparing them to results generated by discriminant analysis, individual judgments, and group judgments. A partial intersection of predictive attributes occurs. More importantly, for all cases tested, the inductively produced knowledge structures perform better than the competing models.

Partially Adaptive Estimation of Regression Models via the Generalized T Distribution

Abstract: This paper considers M-estimators of regression parameters that make use of a generalized functional form for the disturbance distribution. The family of distributions considered is the generalized t (GT), which includes the power exponential or Box-Tiao, normal, Laplace, and t distributions as special cases. The corresponding influence function is bounded and redescending for finite “degrees of freedom.” The regression estimators considered are those that maximize the GT quasi-likelihood, as well as one-step versions. Estimators of the parameters of the GT distribution and the effect of such estimates on the asymptotic efficiency of the regression estimates are discussed. We give a minimum-distance interpretation of the choice of GT parameter estimate that minimizes the asymptotic variance of the regression parameters.

The four generations of computerized educational measurement

Abstract: Educational measurement is undergoing a revolution, due to the rapid dissemination of information-processing technology. One of the most notable aspects of that revolution is the rapidity with which it has come upon us. It is perhaps inevitable that the recent growth in power and sophistication of computing resources and the widespread dissemination of computers in daily life have brought about irreversible changes in educational measurement. Recent developments in computerized measurement are summarized by placing them in a four-generation framework, in which each generation represents a genus of increasing sophistication and power. Generation 1. Computerized testing (CT): administering conventional tests by computer Generation 2. Computerized adaptive testing (CAT): tailoring the difficulty or contents of the next piece presented or an aspect of the timing of the next item on the basis of examinees' responses Generation 3. Continuous measurement (CM): using calibrated measures embedded in a curriculum to continuously and unobtrusively estimate dynamic changes in the student's achievement trajectory and profile as a learner Generation 4. Intelligent measurement (IM): producing intelligent scoring, interpretation of individual profiles, and advice to learners and teachers, by means of knowledge bases and inferencing procedures While acknowledging the obvious pitfalls associated with proposing a framework in a developing field, the authors hope that the suggested framework will provide an ad interim contribution to the field's universe of discourse and facilitate communication about the rapidly developing issues.

Device and method for correction of robot inaccuracy

Abstract: A method and device for improving orientation and/or location accuracy of a programmable robot with respect to a target object. The method consists of calibrating the position of a terminal control frame associated with a robot end-effector which is coupled to a robot distal link. Separated reference positions external from the robot are identified, as to geometry and spatial data. This identification data is stored for later recall and comparison for use in determining a localized relative frame of reference. The robot end-­effector is moved to a first reference position and a rigid body error correction is determined. This correction is stored in computer memory for application to later computer movement.

Predicting Radiative Transfer in Axisymmetric Cylindrical Enclosures Using the Discrete Ordinates Method

Abstract: Radiation codes have been developed based on the S 2 and S 4 discrete ordinates approximations which involve solving the radiation transport equation in 4 and 12 directions, respectively. Evaluation of the codes against exact numerical solutions and experimental data show that both these approximations predict radiative fluxes with acceptable accuracy. The models are also evaluated treating them as part of an overall predictive scheme for pulverized coal combustion. The comparative importance of the various input parameters on the model predictions is evaluated via a detailed sensitivity study based on Fourier analysis technique. This analysis shows that the predictions arc most sensitive to the particle number densities and temperatures, while little sensitivity to the absorption and scattering efficiencies is detected.

Ordovician sphinctozoan sponges of alaska and yukon territory

Abstract: ABSTRAcr-In Coal Creek Canyon, Utah, the Spring Canyon Member of the Blackhawk Formation is divisible into four regressive hemicycles of deposition, each representing the downdip part of a nearshore-to-offshore sequence. The first and fourth hemicycles are best developed. Individual bedding units span middle-shoreface to lower-offshore lithofacies, the latter corresponding to a thin intertongue of Mancos Shale. Trace fossil assemblages include ~22 ichnospecies and 17 ichnogenera: Ancorichnus, Aulichnites, Chondrites, Cylindrichnus, Ophiomorpha, Palaeophycus, Phoebichnus, Planolites, Rosselia, Schaubcylindrichnus, Scolicia, Skolithos, Taenidium, Teichichnus, Terebellina, Thalassinoides, and Uchirites. Diversity and abundance of ichnospecies are greater in nearshore than in offshore lithofacies. Distal deposits are typified by obscure bioturbate textures: Cylindrichnus concentricus, Palaeophycus heberti, and Rosselia socialis are prevalent through the remainder of the lithofacies suite. Ophiomorpha irregulaire and Schaubcylindrichnus coronus are most common in middle-shoreface beds and Chondrites ichnosp. in upper-offshore beds; Ophiomorpha nodosa and O. annulata also are common in this part of the sequence.

Predicting Radiative Transfer in Rectangular Enclosures Using the Discrete Ordinates Method

Abstract: Discrete ordinates solutions of the radiative transfer equation in two-and three-dimensional rectangular enclosures containing absorbing-emitting-scattering media have been obtained using S2, Se, Sg and Sg, approximations. Evaluation against exact analytical and numerical solutions show that while all of these approximations provide acceptable predictions of the radiation fluxes in twodimensional enclosures, use of the higher order (higher than S1,) approximations is not justified due to substantial increase in computational time and negligible improvement in the accuracy of the predictions. However, for three-dimensional enclosures, the 52 approximation is grossly in error. S1 S1) and S5, approximations predict wall heat fluxes and the temperatures of the medium accurately in these enclosures, but, once again, S4, approximation is shown to be adequate. A study of the sensitivity of the predicted net heat absorption by the walls to the dimensions of the system, and radiative properties of the medium and t...

Toward Culturally Sensitive Theories of Culture Change

Abstract: Existing theories of culture change in organizations generally fail to take the nature of the culture to be changed into account. It is suggested here that different cultures may change through different processes. Factors that influence the persistence of culture and the impact that organizational history has on culture change are discussed. Implications for future research are explored.

Distribution of Energy Use and Biomass Among Species of North American Terrestrial Birds

Abstract: The distribution of biomass and energy use among species with different body sizes provides an empirical basis for studying ecological processes that determine species diversity. Biomass and energy use distributions were determined for North Amer- ican terrestrial birds from data on population density and body mass of 380 species and data on energy use obtained from the literature. Using these data, several hypotheses regarding the specific form of biomass (summed for all species in a body size category) and energy use distributions were evaluated. Biomass continued to increase in successive log body mass intervals, but this was not due simply to increasing species numbers. Energy use initially increased in these same intervals but leveled off above a body mass of 80 g. Energy used by average populations of individual species was uniformly distributed between the lower and upper bounds of each log body mass interval. In addition, the upper boundaries on biomass and energy use for individual species paralleled closely the biomass and energy use distributions. Quali- tatively similar patterns were obtained for plant- and animal-eating birds considered sep- arately, and for birds in 14 arbitrarily defined subregions of the North American continent. There were important quantitative differences among energy use distributions for the 14 subregions. Subregions at lower latitudes had energy use distributions that were nearly an order of magnitude higher than those of regions at higher latitudes. These results imply that previous hypotheses to explain biomass and energy use distributions were not of sufficient generality to account for both similarities among distributions of very different systems (e.g., birds and aquatic plankton) and spatial variation among systems composed of similar species. A more general hypothesis should consider the importance of inherent physiological constraints on energy use and environmental limitations on energy avail- ability. The processes that influence resource allocation in a large assemblage of many species may result in statistical patterns of energy use and biomass that tend to maximize ecological quantities analogous to entropy in statistical physical systems.

Digital Neural Networks

Abstract: Demands for applications requiring massive parallelism in symbolic environments have given rebirth to research in models labeled as neural networks. These models are made up of many simple nodes which are highly interconnected such that computation takes place as data flows amongst the nodes of the network. To present, most models have proposed nodes based on simple analog functions, where inputs are multiplied by weights and summed, the total then optionally being transformed by an arbitrary function at the node. Learning in these systems is accomplished by adjusting the weights on the input lines. This paper discusses the use of digital (boolean) nodes as a primitive building block in connectionist systems. Digital nodes naturally engender new paradigms and mechanisms for learning and processing in connectionist networks. The digital nodes are used as the basic building block of a class of models called ASOCS (Adaptive Self-Organizing Concurrent Systems). These models combine massive parallelism with the ability to adapt in a self-organizing fashion. Basic features of standard neural network learning algorithms and those proposed using digital nodes are compared and contrasted. The latter mechanisms can lead to vastly improved efficiency for many applications.

Initiation of sexual activity among female adolescents.

Abstract: According to the 1982 National Survey of Family Growth 46% women aged 15-19 had experienced premarital intercourse. Projections based on this study show that by their 20th birthdays 70% of all women in the US will have experienced premarital intercourse. This article examines the effects of various factors on the likelihood that teenagers will become sexually active. Data for this study were taken from the National Survey of Family Growth Cycle III. Fieldwork was done in 1982 and included interviews of 7969 women aged 15-44. Data include background characteristics measures of fertility and contraception measures of fecundity and birth expectations use of family planning services and the respondents marital history. The study concludes that family stability (intact families) Hispanic ethnicity high parental education religious affiliation regular church attendance and reproductive education decrease the occurrence of 1st intercourse. Other factors characterize an environment that is unstable and unstructured and has a liberalizing influence upon 1st intercourse. Teens from broken homes blacks and the lower social classes are more likely to initiate intercourse. Geographic factors have a very small influence upon the initiation of sexual activity among teens. Similar patterns of influence appear regarding contraceptive use. The same factors that encourage stability such as high fathers education Catholic or Jewish religious affiliation religious attendance and reproductive instruction shift the odds in favor of contracepted rather than noncontracepted sex. Family instability and low social class increase the risk that 1st intercourse will not be contracepted. Providing too much sex education such as instruction on birth control may actually contribute to the leniency of the environment although the authors find no evidence that school-based birth control instruction increases the chances that contraceptives will be used. Environments that are too restrictive increase the chance that 1st intercourse will be noncontracepted. In sum adolescents need an environment balanced between the liberal and conservative extremes to reduce the rate of 1st intercourse and to increase the use of contraception at intercourse.

Sexual attitudes and behavior of high school students in relation to background and contextual factors.

Abstract: Although premarital sexuaUty has been an important area of research for several decades, researchers (e.g., Ehrmann, 1964; Reiss, 1960, 1967) empha? sized attitudes or standards and mostly used college-age samples. One of the major recent shifts in this area has been toward studying younger adolescents (Chilman, 1983; Coales & Stokes, 1986; Diepold & Young, 1979; Sorensen, 1973). National sample surveys have documented that the proportion of adolescents who have had intercourse increased during the 1970s (Zelnik, Kantner, & Ford, 1981) and increases with age (Pratt, Mosher, Bachrach, & Horn, 1984). Estimates in 1986 were that 53% of female and 61% of male 17-year-olds have had intercourse (Harris & Associates, 1986). Another factor traditionally associated with adolescent sexual behavior is more widespread sexual activity among males than females, but there is con? siderable evidence that sex differences are diminishing (Coales & Stokes, 1986; Jessor & Jessor, 1975; Robinson & Jedlicka, 1982). ReUgious participation and church attendance are inversely related to sexual permissiveness of college students (Davids, 1982; Notzer, Leuvan, Mashiach, & Soffer, 1984; Reiss, 1967; Reiss & Miller, 1979; Sack, Keller, & Hinkle, 1984; Young, 1982) and younger teenagers (Harris & Associates, 1986). Living with a single parent is related to more permissive teen sexual attitudes and behavior (Harris & Associates, 1986), even after controlling relevant contaminating variables (Rodgers, 1983; Thornton & Camburn, 1987) as is lower social class (Chilman, 1983; Harris & Associates). The present analyses were undertaken, first, to go beyond the previously reported bivariate relationships and ascertain how a number of background and contextual variables relate to sexual attitudes and behavior when they are combined in a multivariate analysis. A second purpose was to do this analysis with a recent and younger (high school-aged) sample of adolescents.

Measurement and prediction of entrained-flow gasification processes.

Abstract: A detailed mathematical model is used to predict local and effluent properties within an axisymmetric, entrained-flow gasifier. Laboratory experiments were conducted to provide local properties for four coal types from a gasifier operating at near-atmospheric pressure. Effects of selected model parameters and test variables were examined and compared with measurements in most cases. The comparison of predictions and measurements provides the first evaluation of capabilities and limitations of a comprehensive model for entrained-flow gasifiers.

Comparison of Bulk, Emulsion, Thin Sheet Supported, and Hollo Fiber Supported Liquid Membranes in Macrocycle-Mediated Cation Separations

Abstract: The advantages, disadvantages, and possible applications of macrocycle-mediated bulk, emulsion, supported and hollow fiber liquid membranes have been investi-gated. The relative transport rates of the alkali metal cations and of Zn(II), Cd(II) and Hg(II) in sin-gle and competitive cation experiments are studied and compared in the different membrane types. The four membrane types demonstrate similar selectivities but significantly different cation fluxes under comparable conditions using analogous macrocyclic carriers. The degree of distribution of the macrocycle to the organic membrane which is necessary for significant transport varies dramatically among the membrane types, each of which requires unique solvent characteristics. In the experiments, either l8-crown-6, dicyclohexano-l8-crown-6, or 4,1′(5)bis(1-hydroxyheptylcyclohexano)-l8-crown-6 were incorporated into bulk (chloroform, raethylene chloride), emulsion (toluene), supported (phenylhexane) and hollow fiber (phenylhexane or 1-octanol) ...

Molecular cloning and expression of the Bacillus anthracis edema factor toxin gene: a calmodulin-dependent adenylate cyclase.

Abstract: The Bacillus anthracis exotoxin is composed of a lethal factor, a protective antigen, and an edema factor (EF). EF is a calmodulin-dependent adenylate cyclase which elevates cyclic AMP levels within cells. The entire EF gene (cya) has been cloned in Escherichia coli, but EF gene expression by its own B. anthracis promoter could not be detected in E. coli. However, when the EF gene was placed downstream from the lac or the T7 promoter, enzymatically active EF was produced. The EF gene, like the protective antigen (pag) and lethal factor (lef) genes, was present on the large B. anthracis toxin plasmid pXO1. Images

Process of removing and concentrating desired molecules from solutions

Abstract: A method is disclosed for the quantitative removal and concentration of desired molecules or ions, such as gases, anions and amino acids, from a source solution which may contain larger concentrations of other molecules. The method comprises bringing the source solution into contact with a solid cation-ligand-matrix consisting of a cation complexed to a ligand molecule covalently bonded to a matrix consisting of an organic spacer bonded to a solid inorganic support through a silicon atom. The cation has an affinity for the desired molecules to form a complex between the desired molecules and the cation portion of the solid cation-ligand-matrix at binding sites initially held by H₂O or other weakly coordinated ligands or via ion pairing. The desired molecule complex is broken releasing either the desired molecules or desired molecules complexed with the cation by contacting the solid cation-ligand-matrix-desired molecule complex with a much smaller volume of a receiving solution in which said desired molecules are soluble. The concentrated ions or molecules thus removed may be analyzed and/or recovered by known methods. The process is useful in measuring the concentrations of molecules originally present at parts per billion levels; in the removal of low levels of toxic molecules such as ammonia or anions such as chromate from potable and saline water; in the preparation of ultrapure salts and gases; and in the recovery of valuable molecules present in low concentrations as in the separation of amino acids, etc.

A cache coherence approach for large multiprocessor systems

Abstract: This paper explores the architecture of high-performance large scale multiprocessors using private caches for each processor. The caches reduce the average memory access time, but they also result in the well known cache coherence problem. Multiple copies of each memory location are allowed to exist but they must be kept consistent with each other. In this paper, we present a solution to the cache coherence problem specifically for shared bus multiprocessors that adapts dynamically to the reference pattern. Simulation results are presented that demonstrate the high level of performance relative to other protocols particularly during intervals with high levels of sharing.The paper then presents a coherence solution for large multiprocessor systems organized around a hierarchy of buses. One of the first solutions of this kind, the hierarchical protocol is an extension of the adaptive shared bus approach described in this paper.

Thermodynamic quantities for the interaction of SO 4 2− with H + and Na + in aqueous solution from 150 to 320°C

Abstract: The aqueous reactions, $$\begin{gathered} H^ + + SO_4^{2 - } = HSO_4^ - ,Na^ + + SO_4^{2 - } = NaSO_1^ - , \hfill \\ and H^ + + HSO_4^ - = H_2 SO_4 (aq) \hfill \\ \end{gathered} $$ were studied as a function of ionic strength(I) at 150, 175, 200, 250, 300 and 320°C using a flow calorimetric procedure. Log K, ΔH, ΔS and ΔC p values at I=0 were derived from the data at each temperature. Using these experimental values, equations describing log K, ΔH, ΔS and ΔC p at I=0 and temperatures from 150 to 320°C were derived for each system. The use of equations containing identical numbers of positive and identical numbers of negative charges on both sides of the equal sign (isocoulombic reaction principle) was evaluated as a technique for the extrapolation of log K values valid below 100°C to temperatures above 150°C. This evaluation indicated that the principle gives good estimates up to 320°C.

Monitoring the metropolitanization process.

Abstract: Alternative approaches have led to different interpretations of the metropolitanization process in the United States. We identify and illustrate several methods and procedures for monitoring metropolitan-nonmetropolitan population change using the 1950–1980 U.S. decennial censuses. Two basic approaches are compared: constant area approaches and component methods. In addition, we assess the effects of changing metropolitan definitions on metropolitan-nonmetropolitan growth. The results clearly reveal that the underlying mechanics of metropolitanization not only are complex but have changed substantially during the 1950–1980 period. We conclude with observations regarding the use of these procedures in future research.