Online Impression Management: Personality Traits and Concerns for Secondary Goals as Predictors of Self‐Presentation Tactics on Facebook

This study investigates the utility of personality traits and secondary goals as predictors of self‐presentation tactics employed by Facebook users. A structural equation model of self‐presentation tactics on Facebook was proposed and tested. Although fit of the initial model was good, the final model, eliminating three paths and adding two others, yielded a significantly better fitting model. Findings show that personality traits predicted concern for secondary goals (N = 477) and that secondary goals predicted the use of various self‐presentation tactics used on Facebook. Results indicated that these personality traits and secondary goals are both theoretically and empirically sound components for the conceptualization of online impression management.     

FAST AND ROBUST INCREMENTAL ACTION PREDICTION FOR INTERACTIVE AGENTS

The ability for a given agent to adapt on-line to better interact with another agent is a difficult and important problem. This problem becomes even more difficult when the agent to interact with is a human, because humans learn quickly and behave nondeterministically. In this paper, we present a novel method whereby an agent can incrementally learn to predict the actions of another agent (even a human), and thereby can learn to better interact with that agent. We take a case-based approach, where the behavior of the other agent is learned in the form of state–action pairs. We generalize these cases either through continuous k -nearest neighbor, or a modified bounded minimax search. Through our case studies, our technique is empirically shown to require little storage, learn very quickly, and be fast and robust in practice. It can accurately predict actions several steps into the future. Our case studies include interactive virtual environments involving mixtures of synthetic agents and humans, with cooperative and/or competitive relationships.     

Analysis of the temperature effect on the components of plant digestibility in two populations of perennial ryegrass

For the development of mechanistic models of herbage digestibility, quantitative insight into the effects of age, temperature and cultivar on digestibility characteristics of individual plant parts is needed. Towards that goal, glasshouse experiments were conducted at day/night temperatures of 13/8, 18/13 and 23/18 °C with vegetative and reproductive crops of two populations of perennial ryegrass (Lolium perenne L) selected for differences in leaf blade digestibility. Cell wall content (CWC) and true cell wall and organic matter digestibility (CWD and OMD) of vegetative and reproductive tillers were related to dimensions, mass, CWC and digestibility of separate plant parts. Compared with the vegetative tillers, the reproductive tillers had higher rates of leaf appearance, organic matter growth and CWD decline. Strikingly, for both tiller types, no direct effect of temperature on whole tiller CWD was observed, since temperature effects could be eliminated completely by relating CWD to development stage (DVS) expressed as number of leaves appearing on the main tiller. Temperature effects on CWD were restricted to its influence on tiller development rate only. The decline of CWD of individual plant parts with DVS in the reproductive tillers could be described with a negative exponential curve, which reached an asymptote that was higher for leaf blades (755 g kg^?1) than for leaf sheaths (491 g kg^?1) and stem internodes (230 g kg^?1). However, all plant parts in both tiller types had the same fractional CWD decline rate of 0.395 per leaf appearance interval, independent of plant part insertion level, population or temperature. Differences between temperature treatments in OMD were caused by the higher CWC of plant parts at higher temperature, due to a stronger decline of the specific organic matter mass than of the specific cell wall mass of plant parts at increasing temperature. Differences in whole tiller OMD between populations were observed only for vegetative tillers and were also caused by differences in CWC. It is concluded that temperature increase accelerated both the tiller development rate and the rate of decline of CWD during aging to the same extent, whereas plant parts responded similarly in the fractional CWD decline pattern as a function of DVS. These trends offer unique possibilities for modelling grass digestibility under contrasting temperature regimes. © 2003 Society of Chemical Industry     

Measurement of the modulation transfer function of digital X-ray detectors with an opaque edge-test device

A variant of the edge method for the determination of the pre-sampled modulation transfer function (MTF) of digital X-ray imaging devices has been developed and accepted as the standard method in the novel DQE measurement standard IEC 62220-1. An opaque tungsten edge-test device accomplishes the ideal step-like profile of the incident X rays. The edge spread function is measured over a large region across the edge transition that enables an accurate MTF measurement including the 'low-frequency drop'. The method has been applied to different state-of-the-art X-ray imaging detectors, a computed radiography, a CsI-based indirect and an Se-based direct flat-panel detector. The MTF measurement results will be presented. In contrast to the opaque edge device, the commonly used semi-transparent edge-test devices produce scatter radiation that deteriorates the incident X-ray profile, which leads to a systematic overestimation of the MTF.     

Numerical Modeling of Free Surface Dynamics of Melt in an Alternate Electromagnetic Field: Part I. Implementation and Verification of Model

By means of ANSYS Classic and ANSYS CFX external coupling, a numerical model for free surface dynamics of electrically conductive fluid in an alternate electromagnetic field is developed. Volume of Fluid (VOF) numerical technique and k–ω SST turbulence model are applied for the high Reynolds number two-phase flow calculation. The model is extended on 3D and adjusted for the case of electromagnetic levitation. Results for the steady-state free surface shapes obtained with transient calculations are compared with other models and experimental measurements in induction furnaces, induction furnace with cold crucible, and electromagnetic levitation melting device. Numerical calculation results of free surface dynamics are compared with analytic estimation of free surface oscillation period. Parameter studies by means of developed approach and comparison between 3D simulations of free surface dynamics of electromagnetically induced flow with k–ω SST and large eddy simulation (LES) turbulence models are discussed in the second part of the article to follow.     

Potential effects of climate change and eutrophication on a large subtropical shallow lake

In many aquatic ecosystems, increased nutrient loading has caused eutrophication, which is reflected in the trophic structure of the ecosystem. In Lake Mangueira, a large shallow subtropical lake in Brazil, nutrient loading has also increased, but it is still unclear what the effects of this increase will be and how this relates to climate change. To evaluate the effects of increased nutrient loadings in such large lake one would need to integrate hydrological and ecological processes into one model, an approach that has rarely been used before. Here, we apply different versions of a complex 3D ecological model, called IPH-TRIM3D-PCLake, which describes the integrated hydrodynamic, water-quality, and biological processes in the lake. First, the nutrient loadings from the watershed were estimated using a separate hydrological water quality model of the watershed based on field data. Second, we calibrated the 3D ecological model for a 6-year monitoring period in the lake using a simplified non-spatial version of the model. Finally, the calibrated ecological model was applied to evaluate the spatial explicit effects of different scenarios of land use, water pumping for irrigation, and climate change. On short term (1.5 year), the system seemed to be rather resilient, probably because of the lake size related to its high inertia. Our simulations indicated warming can increase water transparency in Lake Mangueira which may be related to two factors: (a) the current meso-oligotrophic state of the lake which may easily lead to nutrient limitation; and (b) submerged macrophytes grow during the whole season. The combined effect of climate change and increased nutrient loading, less strong than increased nutrient loading alone. The model can only be used for qualitative predictions of the effect of management scenarios, such as maintenance of water levels in the dry season, and water-pumping rules for irrigation in order to maintain the ecosystem structure and functions in the future under additional stress caused by increased use or climate change.     

Enhancing computer graphics through machine learning: a survey

Machine learning has experienced explosive growth in the last few decades, achieving sufficient maturity to provide effective tools for sundry scientific and engineering fields. Machine learning provides a firm theoretical foundation upon which to build techniques that leverage existing data to extract interesting information or to synthesize more data.In this paper we survey the uses of machine learning methods and concepts in recent computer graphics techniques. Many graphics techniques are data-driven; however, few graphics papers explicitly leverage the machine learning literature to underpin, validate, and develop their proposed methods. This survey provides novel insights by casting many existing computer graphics techniques into a common learning framework. This not only illuminates how these techniques are related, but also reveals possible ways in which they may be improved. We also use our analysis to propose several directions for future work.     

A Flexible and Energy-Efficient Coarse-Grained Reconfigurable Architecture for Mobile Systems

Two of the most important design issues for next generation handheld devices are wireless networking and the processing of multimedia content. Both applications rely heavily on computationally intensive digital signal processing algorithms. Programmable architectures that keep pace with the increasing performance requirements become more and more power hungry. This is problematic for a battery powered mobile device, since it has only a limited amount of energy available. Conversely, dedicated architectures are too inflexible to keep pace with changing standards and feature sets. A mobile device requires high-performance, flexibility and (energy-)efficiency. These contradicting requirements need to be balanced in the system architecture of a mobile device. In this paper a heterogeneous architecture of domain specific processing tiles is proposed. The focal point is the coarse-grained reconfigurable architecture of the Montium processing tile, which is designed to execute digital signal processing algorithms energy-efficiently.