Showing papers by "Clemson University published in 1986"

Experimentation in software engineering

Abstract: A framework is presented for analyzing most of the experimental work performed in software engineering over the past several years. The framework of experimentation consists of four categories corresponding to phases of the experimentation process: definition, planning, operation, and interpretation. A variety of experiments are described within the framework and their contribution to the software engineering discipline is discussed. Some recommendations for the application of the experimental process in software engineering are included.

Crop simulation models in agronomic systems.

Abstract: Publisher Summary This chapter discusses some crop simulation models in agronomic systems. Many crop models or parts of crop models have been built to help the researcher and students understand the operation of some part of an agronomic cropping system, for example, soil water flow, stomata1 control, or fertilizer nutrient movement. In addition to understanding various parts of agronomic systems, the modelers want to see what can be expected to happen if some change is made in that system. Field tests are very expensive, especially as the numbers of variables and/or treatments increase, and years of results are needed. A proven model of the system helps to evaluate these treatments and indicates which ones could be expected to give the desired results. The cotton model, GOSSYM, has been widely validated. GOSSYM has been used in a user-friendly form on a PC microcomputer as a tool for on-farm management decisions pertaining to nitrogen fertilizer applications, irrigation scheduling, and timing of harvest-aid chemicals. By combining GOSSYM with an expert system program, COMAX, the on-farm management decisions have been run in several combinations to give the user an optimal plan for fertilizer and irrigation scheduling.

Performance Analysis of Local Computer Networks

Abstract: In this age of modern era, the use of internet must be maximized. Yeah, internet will help us very much not only for important thing but also for daily activities. Many people now, from any level can use internet. The sources of internet connection can also be enjoyed in many places. As one of the benefits is to get the on-line performance analysis of local computer networks book, as the world window, as many people suggest.

A Tight Linearization and an Algorithm for Zero-One Quadratic Programming Problems

Abstract: This paper is concerned with the solution of linearly constrained zero-one quadratic programming problems. Problems of this kind arise in numerous economic, location decision, and strategic planning situations, including capital budgeting, facility location, quadratic assignment, media selection, and dynamic set covering. A new linearization technique is presented for this problem which is demonstrated to yield a tighter continuous or linear programming relaxation than is available through other methods. An implicit enumeration algorithm which uses Lagrangian relaxation, Benders' cutting planes, and local explorations is designed to exploit the strength of this linearization. Computational experience is provided to demonstrate the usefulness of the proposed linearization and algorithm.

Sex differences in levels of tolerance and attribution of blame for sexual harassment on a university campus

Abstract: Although the issue of sexual harassment on college campuses has been discussed in the literature for the last five years, little attention has been paid to sex differences in levels of tolerance and attribution of blame in harassment. The current survey, based on a random sample of faculty, students, and staff at a large southern university, details sex differences in definitions of harassment, in attitudes toward causes, in attitudes toward romantic relationships between faculty and students, and in attitudes toward university policy. The authors suggest that sex differences reflect differing perceptions by men and women of their own self-interests within the university, and the organizational environment. Attention is also directed to the explanatory power of attribution theory.

Joint torques for control of two coordinated moving robots

Abstract: Tasks for two coordinated industrial robots always bring the robots in contact with a same object. Physically the three form a closed kinematic chain mechanism. When the chain is in motion, the positions and orientations of the two robots must satisfy a set of holonomic equality constraints for every time instant. To eliminate motion errors between them, one of them is assigned to carry the major part of the task. Its motion is planned accordingly. The motion of the second robot is to follow that of the first robot as specified by the relations of the joint velocities derived from the constraint conditions. Thus if any modification of the motion is needed in real time, only the motion of the first robot is modified. The modification for the second robot is done implicitly through the constraint conditions. Specifically, when the joint displacements, velocities, accelerations and torques/forces of the first robot are known for the planned or modified motion, the corresponding variables for the second robot can be determined through the constrained relations.

Complexity in Long-term Contracts: An Analysis of Natural Gas Contractual Provisions

Abstract: Long-term contracts in the coal, geothermal, uranium, and natural gas industries, among others, often include complex quantity and price provisions. Several explanations for contractual complexities of these kinds have been advanced. The earliest is that such complex provisions are a manifestation of market power. A second possibility is that the quantity and price provisions of long-term contracts are methods of allocating risk. A third explanation stems from the transaction cost framework of Coase, Klein et al., and Williamson (1979, 1985). The transaction cost hypothesis maintains that economic organization varies systematically with the condition of asset specificity. This is amenable to empirical testing. Indeed, there is a growing empirical literature testing this hypothesis (Joskow, Masten, Monteverde and Teece, and Palay (1984, 1985)). In this paper I analyze and empirically test a number of hypotheses on the role of the contractual provisions in the natural gas industry. I compare the

Mean Flow Characteristics of a Turbulent Offset Jet

Abstract: A detailed study of the mean flow characteristics of a turbulent offset jet is presented. The flow is characterized by a longitudinal variation of curvature, skewed impingement onto a flat surface, a recirculating region, and the development of a wall jet region. Flow structure is described in the preimpingement, recirculation and impingement regions. An interdependence is shown among the pressure differential across the jet, jet curvature and entrainment. The magnitude of the curvature strain rate is found to be significant and implies that this flow cannot be accurately modelled as a thin shear layer. The jet decay and spread rates are similar to those of a plane jet if appropriate curved coordinates are used. The extent of the impingement region is approximately 20 nozzle widths downstream, in agreement with previous studies.

The relationship between satellite measured convective bursts and tropical cyclone intensification

Abstract: The relationship between the mean temperature of the top of the cloud canopies and the future maximum winds of Atlantic Ocean tropical cyclones is analyzed. The area-average cloud top temperatures from 309 observations of 12 tropical cyclones which occurred during 1974–79 were compiled from infrared measurements made by Geostationary Operational Environment Satellites. Maximum winds were obtained from best track records. The satellite measurements showed that prolonged surges of intense convection developed in the near region surrounding the depression centers before the maximum winds initially increased. Subsequent weakening of the convection occurred but was frequently followed by new surges of intense convection. It was found that when these prolonged surges of intense convection 1asted for 9 or more hours, and the filtered (6-h running mean) area-average cloud top temperature within 222 km of the tropical cyclone centers was 238 K or less, that the maximum winds of the tropical cyclones incre...

Weathering characteristics of hardwood surfaces

Abstract: Four hardwoods, red oak, white oak, yellow-poplar, and sweetgum, were exposed to outdoor weathering and to artificial ultraviolet (UV) light with wavelengths of λ>220 and >254 nm. Discoloration and loss of brightness were observed from all specimens regardless of their exposure conditions. White oak and sweetgum changed color at a slower rate than did red oak and yellow-poplar. SEM micrographs showed that all wood species exhibited surface deterioration after 30 days exposure to sunlight or 500 hrs to UV light. Loss of middle lamella, separation of procumbent cells, and damage of pit structures were observed on transverse sections for all species. ESCA studies revealed a high oxygen content at the wood surfaces indicating severe oxidation of wood exposed either outdoors or to artificial UV light. The generation of new chromophoric groups such as carbonyls, carboxylic acids and quinones, and the loss of lignin at the oxidized surface were demonstrated experimentally by infrared studies.

A probabilistic permeability model and the pore size density function

Abstract: Mathematical interpretation of the pore size disribution (PSD) data as measured by mercury intrusion porosimetry was revealed in detail. The PSD data were commonly presented as cumulative intruded volume per gram of specimen versus pore size. In this paper, however, they were expressed in a dimensionless term for convenient mathematical operations. The pore size density function was deduced from the PSD data using the finite difference approximation and curve-fitting technique. For the prediction of permeability, first the published correlations between permeability and pore geometry were critically reviewed. A probabilistic permeability model based on the pore size density function was then developed, which can be thought of as a generalization of Childs and Collis-George's model. Predictions of permeability of the compacted soils studied using the developed model were very good for a wide range of permeabilities.

Selecting interrelated R & D projects in space technology planning

Abstract: A decision support model and solution procedure are presented for selecting interrelated R and D projects in space technology planning. Technical and benefit interactions among projects are explicitly considered. The problem addressed is that of selecting among technologically enabling and value enhancing projects. A 0-1 integer programming model is formulated and a solution technique is presented that places technology project sets into two categories: (1) those the decision-maker should consider, and (2) those that are dominated by sets in the first category. Use of the model and solution techniques is demonstrated in the context of a NASA case example pertaining to Earth resources space programs. The efficiency of the model (with the solution technique) in reducing an unmanageably large number of feasible and efficient sets is demonstrated in the example problem.

Bidens pilosa complex (asteraceae) in north and central america

Abstract: Field observations, chromosome counts, flavonoid chemistry, breeding system data, hybridization experiments, and a quantitative analysis of twelve morphological features combine to show that the North and Central American populations of B. pilosa sensu Sherif actually include three distinct species: B. odorata (n = 12), B. alba (n = 24), and B. pilosa (n = 36). All these taxa are square-stemmed, white-rayed or discoid annuals with linear, obcompressed-quadrangulate achenes, but each species can be distinguished morphologically by differences in ray length and width, in outer phyllary length, width and shape and chemically by differences in the chalcones accumulated in their leaves. New combinations are proposed and two varieties, B. odorata var. oaxacensis and B. odorata var. chilpancingensis, are described as new. Descriptions, distribution maps, synonymies, and a key to all taxa are provided. BIDENS PILOSA L. (Asteraceae) is a widely distributed subtropical and tropical weed with its center of diversification in Mexico. Throughout its range, this taxon is recognized by its annual habit, square stem, and linear, obcom

Seasonal Distribution of Thermotolerant Free‐Living Amoebae. I. Willard's Pond

Abstract: A quantitative study of the seasonal distribution of thermotolerant (37 degrees C and 45 degrees C), small free-living amoebae (FLA) was conducted in Willard's Pond, a warm, monomictic lake in the Piedmont region of South Carolina. Correlation of physical and chemical parameters with the seasonal distribution was facilitated by partitioning the aquatic ecosystem into benthic, planktonic, and neustonic habitats. Population densities of FLA peaked in late summer in each habitat; however, species composition varied between habitats. Littoral sediment appeared to be the major habitat for FLA, with peaks in populations of Acanthamoeba and Naegleria in August, Hartmannella in July, and Vahlkampfia in May. Populations in profundal sediment underwent dramatic seasonal shifts, apparently in response to the seasonal chemical changes in the hypolimnion. Acanthamoeba was most prevalent in late summer, representing as much as 82% of the FLA in profundal sediment. Distribution patterns and species composition of FLA from surface water were similar to those from littoral sediment; however, a greater percentage of Naegleria was found in surface water. Numerous FLA were isolated from the neustonic community (surface film), and the number of FLA isolated in the surface film at the deep water station was found to be significantly (P less than 0.05) greater than the number from subsurface (5-10 cm) samples. In the water column, FLA populations consistently were highest in the detrital layer, which persisted at a depth of 3.0-3.4 m throughout the summer period. The large percentage of Naegleria contributing to FLA in the detrital layer suggests that Naegleria amoeboflagellates sink through the layer, flagellate, and swim back up, such migrations possibly being triggered by a reduction of nutrients below the layer or by the presence of anoxic, reducing conditions in the hypolimnion. In addition, weather events were found to play a major role in the redistribution of FLA between various habitats in the aquatic ecosystem, with such changes probably due to resuspension of FLA from littoral sediment by wind action and input from the watershed via runoff.

Is Laughter the Best Medicine?: A Study of the Effects of Humor on Perceived Pain and Affect of Humor on Perceived Pain and Affect

Abstract: This paper presents a study of the effects of humor on affect and perceived pain in elderly residents of a long-term care facility. Movies were viewed by two groups (humor and non-humor) and differences between groups were noted on measures of perceived pain and affect. Humor is shown to provide significant benefits to aged clients. Qualitative information on program implementation is included.

The Loneliness Experience of College Students Sex Differences

Abstract: The present study examined sex differences among college students in the quantitative and qualitative aspects of loneliness. Measurements of loneliness, emotional reactivity, and social risk taking were administered to 112 undergraduates. Males evidenced greater self-reported loneliness than females. Generally, affective and social risk-taking measures were more highly related to loneliness among males than females. The results suggest that loneliness is more likely to be associated with negative personal and affective self-evaluations for males than for females. Males may react to loneliness more negatively than females because of a tendency to attribute loneliness to personal failure rather than external, uncontrollable causes. Evidence also suggests that having difficulty in initiating social risks may contribute to loneliness for males more than females.

Effect of curvature on the turbulence of a two-dimensional jet

Abstract: An experimental study is presented which details the turbulence characteristics of a two dimensional offset jet. A single offset ratio (height of the nozzle above the solid parallel wall by nozzle width) of seven is used with a nozzle Reynolds number of 15,000. Measurements are presented in the preattachment jet region made with a dual frequency shifted laser Doppler anemometer. The relative strain rates resulting from curvature on the upper and lower sides of the jet are determined and their effects on the r. m. s. fluctuating velocity components are presented.

Extended Oxygen Delivery from the Nerve Hemoglobin of Tellina alternata (Bivalvia)

Abstract: An oxygen-binding hemoglobin localized in the nerves of Tellina alternata (Bivalvia) required 30 minutes to unload oxygen when excised nerves were exposed to pure nitrogen. Neural excitability under these conditions could be sustained only until deoxygenation of the hemoglobin was complete. When the oxygen-combining function of the hemoglobin was abolished with carbon monoxide, the neural excitability ceased within a few minutes of oxygen removal, a response identical to that of hemoglobinless homologous nerves of other bivalves. These results demonstrate that aerobic activity can be supported by the oxygen stored on hemoglobin in microscopic tissues for a considerable time under anoxic conditions.

Molecular evolution of the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO)

Abstract: The evolutionary relationship of the RuBisCO large subunit gene(s) (rbcL) of several prokaryotes was examined using the technique of heterologous DNA hybridization. Restriction fragments of cloned rbcL from Anacystis nidulans 6301, Chlamydomonas reinhardtii, Rhodospirillum rubrum, and maize were nick-translated and used as probes. The C. reinhardtii and maize probes hybridized with restriction fragment(s) only from cyanobacteria: Agmenellum quadruplicatum, Fremyella diplosiphon, and Mastigocladus laminosus. In addition, the A. nidulans probe hybridized with restriction fragment(s) from Alcaligenes eutrophus, Chromatium vinosum, Nitrobacter hamburgensis, Paracoccus denitrificans, Pseudomonas oxalaticus, Rhodomicrobium vannielii, Rhodopseudomonas capsulata, Rhodopseudomonas palustris, Rhodopseudomonas sphaeroides, Thiobacillus intermedius, Thiobacillus neapolitanus, and Thiothrix nivea. The elucidated fragment of Rhodopseudomonas species is presumably for the Form I RuBisCO LSU of these organisms. The R. rubrum probe hybridized only to a restriction fragment(s) from R. capsulata, R. palustris, R. sphaeroides, T. neapolitanus, and T. nivea. The fragment(s) of Rhodopseudomonas species is the Form II rbcL of these organisms. The restriction fragments of T. neapolitanus and T. nivea were also different from those elucidated by the A. nidulans probe, suggesting the presence of a second (different) rbcL in these organisms. Positive hybridization was not obtained using any of the probes with DNA from Beggiatoa alba, Chlorobium vibrioforme or Chloroflexus aurantiacus. It appears that all rbcL have evolved from a common ancestor. Our data are consistent with and supportive of the evolutionary scheme for RuBisCO proposed by Akazawa, Takabe, and Kobayashi [1].

Mixing/segregation in two‐ and three‐dimensional fluidized beds: Binary systems of equidensity spherical particles

Abstract: A comparison was made of the equilibrium mixing/segregation behavior of binary mixtures of different-sized, equal-density glass beads in two- and three-dimensional fluidized beds. Several empirical equations for mixing index were examined, all involving a dimensionless function of excess gas velocity. This function, which appeared to largely account for the effect of aspect ratio, was found to optimally correlate the data for both types of beds. However, a much better fit was obtained for the threedimensional bed data, most probably because wall effects significantly retarded mixing in the two-dimensional bed.