Showing papers by "Purdue University published in 1983"

Measuring marital quality, A critical look at the dependent variable

Abstract: This paper critically examines the operationalization of marital quality indices used as dependent variables. First, it looks at the functioning and construction of marital quality variables. In particular, Spanier's Dyadic Adjustment Scale is used to illustrate the arguments. Second, it presents both semantic and empirical criteria to judge the development of a marital quality index. Finally, it presents a Quality Marriage Index (QMI) based on the introduced criteria. This index was constructed using data from 430 people across four states. Several advantages of the QMI over more traditional measures are shown in terms of how co variates relate to the index.

A distance measure between attributed relational graphs for pattern recognition

Abstract: A method to determine a distance measure between two nonhierarchical attributed relational graphs is presented. In order to apply this distance measure, the graphs are characterised by descriptive graph grammars (DGG). The proposed distance measure is based on the computation of the minimum number of modifications required to transform an input graph into the reference one. Specifically, the distance measure is defined as the cost of recognition of nodes plus the number of transformations which include node insertion, node deletion, branch insertion, branch deletion, node label substitution and branch label substitution. The major difference between the proposed distance measure and the other ones is the consideration of the cost of recognition of nodes in the distance computation. In order to do this, the principal features of the nodes are described by one or several cost functions which are used to compute the similarity between the input nodes and the reference ones. Finally, an application of this distance measure to the recognition of lower case handwritten English characters is presented.

Circumplex Model of marital and family systems: VI. Theoretical update.

Abstract: This paper updates the theoretical work on the Circumplex Model and provides revised and new hypotheses. Similarities and contrasts to the Beavers Systems Model are made along with comments regarding Beavers and Voeller's critique. FACES II, a newly revised assessment tool, provides both "perceived" and "ideal" family assessment that is useful empirically and clinically.

The rhetoric of identification and the study of organizational communication

Abstract: This essay argues that scholars of rhetoric and communication broaden their conception and application of Kenneth Burke's “rhetoric of identification.” The first part of the essay offers the individual‐organization relationship as an exemplar for understanding and examining the rhetoric of identification. The second section derives a tentative typology of identification strategies and tactics and applies it in a critical assessment of corporate house organs. The essay concludes with an interpretive explication of the process of identification in contemporary business organizations.

Chemical and Physical Structure of Polymers as Carriers for Controlled Release of Bioactive Agents: A Review

Abstract: In a controlled release system a drug, pesticide, or other bio-active agent is incorporated into a carrier, generally a polymeric material. The rate of release of the substance is determined by the properties of the polymer itself and is only weakly dependent on environmental factors (such as the pH of bodily fluids). Controlled release systems are capable of delivering substances slowly and continuously for up to several years.

On the various and changing meanings of organizational membership: A field study of organizational identification

Abstract: The primary aim of this study was to analyze and interpret some aspects of the process of organizational identification in a corporate field setting. Specifically, the study focused on how an individual's identification (or identifying) with an employing organization influences on‐the‐job decision making. Past research efforts have been limited by their treatment of organizational identification as a product or state, rather than as a process. The wider perspective on identification is well represented by Herbert A. Simon and Kenneth Burke, whose writings were integrated to provide a theoretical framework for this study. While this study neither examined the phenomenon of identification over time nor placed it in a clearly‐defined causal chain, it explicitly recognized identification as a continuing development involving many changes. The study employed two methodologies for the examination of identification in a corporate field setting: moderately‐scheduled interviews that produced largely qualitative da...

An Empirical Analysis of Strategy Types

Abstract: Using the PIMS SPIYR data base, which pools cross-section and timeseries data, an empirical study to identify business strategy types was undertaken. Using a two-stage methodological approach combining principal component and cluster analysis on both a consumer products and an industrial products data base, two sets of strategy typologies were identified. Six strategy types were identified for consumer products: (1) harvest, (2) builder, (3) cashout, (4) niche or specialization, (5) climber, and (6) continuity. For industrial products, four strategy types were identified: (1) low commitment, (2) growth, (3) maintenance, and (4) niche or specialization. A discussion of the characteristics of each strategy type is offered.

Formulation and optimization of cubic polynomial joint trajectories for industrial robots

Abstract: Because of physical constraints, the optimum control of industrial robots is a difficult problem. An alternative approach is to divide the problem into two parts: optimum path planning for off-line processing followed by on-line path tracking. The path tracking can be achieved by adopting the existing approach. The path planning is done at the joint level. Cubic spline functions are used for constructing joint trajectories for industrial robots. The motion of the robot is specified by a sequence of Cartesian knots, i.e., positions and orientations of the hand. For an N -joint robot, these Cartesian knots are transformed into N sets of joint displacements, with one set for each joint. Piecewise cubic polynomials are used to fit the sequence of joint displacements for each of the N joints. Because of the use of the cubic spline function idea, there are only n - 2 equations to be solved for each joint, where n is the number of selected knots. The problem is proved to be uniquely solvable. An algorithm is developed to schedule the time intervals between each pair of adjacent knots such that the total traveling time is minimized subject to the physical constraints on joint velocities, accelerations, and jerks. Fortran programs have been written to implement: 1) the procedure for constructing the cubic polynomial joint trajectories; and 2) the algorithm for minimizing the traveling time. Results are illustrated by means of a numerical example.

The structure of bovine rhodopsin.

Abstract: We have isolated 16 peptides from a cyanogen bromide digest of rhodopsin. These cyanogen bromide peptides account for the complete composition of the protein. Methionine-containing peptides from other chemical and enzymatic digests of rhodopsin have allowed us to place the cyanogen bromide peptides in order, yielding the sequence of the protein. We have completed the sequence of most of the cyanogen bromide peptides. This information, in conjunction with that from other laboratories, forms the basis for our prediction of the secondary structure of the protein and how it may be arranged in the disk membrane.

Estimation and choice of neighbors in spatial-interaction models of images

Abstract: Some aspects of statistical inference for a class of spatial-interaction models for finite images are presented: primarily the simultaneous autoregressive (SAR) models and conditional Markov (CM) models. Each of these models is characterized by a set of neighbors, a set of coefficients, and a noise sequence of specified characteristics. We are concerned with two problems: the estimation of the unknown parameters in both SAR and CM models and the choice of an appropriate model from a class of such competing models. Assuming Gaussian-distributed variables, we discuss maximum likelihood (ML) estimation methods. In general, the ML scheme leads to nonlinear optimization problems. To avoid excessive computation, an iterative scheme is given for SAR models, which gives approximate ML estimates in the Gaussian case and reasonably good estimates in some non-Gaussian situations as well. Likewise, for CM models, an easily computable consistent estimate is given. The asymptotic mean-squared error (mse) of this estimate for a four-neighbor CM model is shown tn be substantially less than the mse of the popular coding estimate. Asymptotically consistent decision rules are given for choosing an appropriate SAR or CM model. The usefulness of the estimation scheme and the decision rule for the choice of neighbors is illustrated by using synthetic patterns. Synthetic patterns obeying known SAR and CM models are generated, and the models corresponding to true and several competing neighbor sets are fitted. The estimation scheme yields estimates close to the parameters of the true models, and the decision rule for the choice of neighbors picks up the true model from the class of competing models.

Gender and Social Influence: A Social Psychological Analysis.

Abstract: Men and women are believed to differ in how influential and easily influenced they are: Men are thought to be more influential, and women more easily influenced. In natural settings, men and women tend to differ in these ways, but these differ- ences stem largely from formal status inequalities by which men are more likely than women to have high-status roles. Status is important because of the legitimate authority vested in high-status roles: Within appropriate limits, people of higher status are believed to have the right to make demands of those of lower status, and people of lower status are ex- pected to comply with these demands. Yet, small, stereotypic sex differences in leadership and social influence generally have been found in laboratory experiments and other small-group settings where men and women have equal formal status. These small sex differences may occur because experience with hierarchical social structures in which men have higher status creates expectancies about male and female behavior, and these expectancies affect social interaction in ways that foster behavior that confirms the expectancies. Sex differences that occur in the laboratory as well as natural settings, then, may stem from social structural factors—namely, from the existing distributions of women and men into social roles.

State of the Art-Location on Networks: A Survey. Part I: The p-Center and p-Median Problems

Abstract: Network location problems occur when new facilities are to be located on a network. The network of interest may be a road network, an air transport network, a river network, or a network of shipping lanes. For a given network location problem, the new facilities are often idealized as points, and may be located anywhere on the network; constraints may be imposed upon the problem so that new facilities are not too far from existing facilities. Usually some objective function is to be minimized. For single objective function problems, typically the objective is to minimize either a sum of transport costs proportional to network travel distances between existing facilities and closest new facilities, or a maximum of "losses" proportional to such travel distances, or the total number of new facilities to be located. There is also a growing interest in multiobjective network location problems. Of the approximately 100 references we list, roughly 60 date from 1978 or later; we focus upon work which deals directly with the network of interest, and which exploits the network structure. The principal structure exploited to date is that of a tree, i.e., a connected network without cycles. Tree-like networks may be encountered when having cycles is very expensive, as with portions of interstate highway systems. Further, simple distribution systems with a single distributor at the "hub" can often be modeled as star-like trees. With trees, "reasonable" functions of distance are often convex, whereas for a cyclic network such functions of distance are usually nonconvex. Convexity explains, to some extent, the tractability of tree network location problems.

The swelling interface number as a criterion for prediction of diffusional solute release mechanisms in swellable polymers

Abstract: When a glassy polymer containing a uniformly dispersed solute is brought in contact with a penetrant, solute diffusion will be associated with the transport mechanism and penetration velocity of the penetrant in the polymer. Analysis and prediction of mechanisms of diffusional solute release may be obtained through a new dimensionless number, the swelling interface number, Sw, which compares the relative mobilities of the penetrant and the solute in the presence of macromolecular relaxations in the polymer. It is shown that a sufficient and necessary criterion for time-independent diffusional solute release rates from these swellable systems is that the Sw be smaller than 10−2. The swelling interface number Sw may be related to easily determined structural and thermodynamic parameters of the solute/polymer/penetrant system. Preliminary experimental results of dynamic water swelling of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) and diffusional release of theophylline from initially glassy copolymers show that decreasing values of Sw are related to increased pseudo-case-II transport kinetics of the solute.

Adaptive linear controller for robotic manipulators

Abstract: This paper presents a new approach to the position and velocity control of a manipulator by using an adaptive controller of the self-tuning type for each joint. The complicated manipulator system is modeled by a set of time series difference equations. The parameters of the models are determined by on-line recursive algorithms, which result from minimizing the sum of the squared equation errors. The adaptive controller of each joint is designed on the basis of the difference equation model and a chosen performance criterion. The controller gains are calculated on-line using the model with the estimated values of system parameters. Simulation results are presented to demonstrate the applicability of the approach. Some aspects of the implementation are also discussed.

Dynamic Behavior of a Class of Photovoltaic Power Systems

Abstract: An important consideration in the operation of grid connected photovoltaic power systems is a means of adjusting the photovoltaic array voltage so that maximum output power is achieved for the given atmospheric conditions. The dynamic behiavior of a specific photovoltaic power system which utilizes the well known perturb and observe method of power tracking is examined. Using measured insolation data, it is demonstrated that the perturb and observe method of control migrates considerably from peak power whenever the insolation varies randomly as a result of cloud cover. An alternate method of power tracking is also examined. It is shown that the photovoltaic power system, utilizing the proposed method of power tracking, is able to track accurately peak power conditions during periods of randomly varying insolation.

A computational study of reconstruction algorithms for diffraction tomography: Interpolation versus filtered-backpropagation

Abstract: From the standpoint of reporting a new contribution, this paper shows that by using bilinear interpolation followed by direct two-dimensional Fourier inversion, one can obtain reconstructions of quality which is comparable to that produced by the filtered-backpropagation algorithm proposed recently by Devaney. For an N × N image reconstructed from N diffracted projections, the former approach requires approximately 4N FFT's, whereas the backpropagation technique requires approximately N2FFT's. We have also taken this opportunity to present the reader with a tutorial introduction to diffraction tomography, an area that is becoming increasingly important not only in medical imaging, but also in underwater and seismic mapping with microwaves and sound. The main feature of the tutorial part is the statement of the Fourier diffraction projection theorem, which is an extension of the traditional Fourier slice theorem to the case of image formation with diffracting illumination.

The myth of equality in science classrooms

Abstract: An analysis of the 1976-1977 NAEP survey of science attitudes showed that, by age nine, females, although expressing similar or greater desires to participate in science activities, had consistently fewer experiences in science than boys of the same age. Science activities surveyed included use of common experimental materials and instruments, observation of scientific phenomena, and field trips. At ages 13 and 17, girls again reported fewer classroom and extracurricular science activities than boys. Their responses indicated narrow perceptions of science and of the usefulness of scientific research. In addition, they displayed generally negative attitudes toward science classes and careers. Suggestions to eliminate the inequalities found are offered.

Rapid visual feedback processing in single-aiming movements.

Abstract: A major line of behavioral support for motor-program theory derives from evidence indicating that feedback does not influence the execution and control of limited duration movements. Since feedback cannot be utilized, the motor-program is assumed to act as the controlling agent. In a classic study, Keele and Posner observed that visual feedback had no effect on the accuracy of 190-msec single-aiming movements. Therefore visual feedback processing time is greater than 190 msec, and, more importantly, limited duration movements are governed by motor programs. In the present paper, we observed that visual feedback can affect the spatial accuracy of movements with durations much less than 190 msec. We hypothesize that visual feedback can aid motor control via processes not associated with intermittent error corrections.