Hierarchical directory-based shared memory architecture

We describe the design of a directory-based shared memory architecture on a hierarchical network of hypercubes. The distributed directory scheme comprises two separate hierarchical networks for handling cache requests and transfers. Further, the scheme assumes a single address space and each processing element views the entire network as contiguous memory space. The size of individual directories stored at each node of the network remains constant throughout the network. Although the size of the directory increases with the network size, the architecture is scalable. The results of the analytical studies demonstrate superior performance characteristics of our scheme compared with those of other schemes.

Object extraction using genetic algorithms and morphological processing

This paper introduces a novel methodology for object detection using genetic algorithms and morphological processing. The method employs a kind of object oriented structuring element, which are derived using genetic algorithm operating. The population of morphological filters iteratively evaluated according to a statistical performance index corresponding to object extraction ability, and evolves into an optimal structuring elements using the evolution principles of genetic search. Experimental results of object extraction in high resolution satellite images are presented to illustrate the merit and feasibility of the proposed method.

Women's cognitive and emotional processing during sexual arousal : the effects of erotic film and absorption

Sexual arousal is a complex and dynamic element of women’s sexuality. Accounts vary, however most multidimensional models highlight the cognitive, affective and physiological components of the female sexual arousal response. While literature examining the peripheral physiological changes that occur during female sexual arousal abounds, there has been a dearth of literature pertaining to the cognitive and affective components. Thus, while many authors have included cognitive and emotions as independent components of the female sexual arousal response, there has been little empirical research to validate this approach. The aim of the current thesis was to examine the cognitive and affective components of female sexual arousal in more depth, investigating the nature of the relationship between these components under various experimental conditions. In order to do so, two integrated studies were conducted, each highlighting the effects of either external or internal variables on women’s subjective sexual arousal, absorption, positive affect and negative affect. Study One was designed to evaluate women’s emotional and cognitive processing of two elements of erotic film – foreplay and erotic context. 60 women were asked to report their subjective sexual arousal, absorption, positive affect and negative affect in response to one of four erotic film excerpts. The erotic excerpts varied in accordance with the degree of foreplay (low vs. high) depicted and the context in which the sexual activities took place (novel vs. habitual context). Women in the study responded more favourably to the high foreplay erotic film excerpt, subsequently reporting higher degrees of subjective sexual arousal, absorption and positive affect. Women also responded favourably to the erotic excerpt filmed in a novel context, reporting greater subjective sexual arousal as a result. The environment in which the sexual encounters were filmed failed to have an effect however, on women’s absorption or their positive or negative affect. The results of Study One suggest that stimulus specific variables, such as the degree of foreplay depicted, have a significant influence on female cognitive and emotional processing of erotic film. The results also suggest that a relationship exists between absorption, subjective sexual arousal and positive affect, albeit a correlational one. Specifically, there was evidence of parallel processing during sexual arousal, as participant reported sexual arousal, absorption and positive affect all increased and decreased in unison. Based on the results it was suggested that future research attempt to experimentally manipulate one of these variables, to examine its direct effect on the remaining variable. Thus, Study Two aimed to examine the effects of absorption on women’s cognitive and emotional processing of erotica. Study Two manipulated absorption at two levels (high vs. low), examining the impact of these states on participants’ subsequent absorption, subjective sexual arousal and positive and negative affect. 62 women were asked to read one of two sets of test session instructions. The first, participant-oriented instruction set, instructed participants to immerse themselves in the erotic film excerpt, as if they were active participants in the sexual exchange. The second, spectator-oriented instruction set, directed participants to observe and evaluate the erotic film. These instructions were designed to elicit high and low degrees of absorption, respectively. The utility of this approach when manipulating female absorption, was demonstrated by self reported ratings of absorption, given at the conclusion of the film presentation. Participants were also asked to report their subjective sexual arousal and positive and negative affect at the conclusion of the erotic film presentation. The findings of this study suggest that the adoption of a participant-oriented (high absorption) perspective elicits more favourable responses from participants than a spectator-oriented (low absorption) perspective, with participants in the former experimental group reporting greater degrees of subjective sexual arousal and positive affect. Negative affect was equivalent across experimental conditions, with the participants reporting that they experienced little to no aversive feelings during either of the experimental conditions. The results suggest that the degree to which a women immerses and absorbs herself in a sexual stimulus has a significant impact in her subsequent cognitive and affective processing of that stimulus. More specifically, it appears that women respond more favourably when they are highly absorbed and immersed in a stimulus, reporting greater subjective sexual arousal and positive affect. Overall, the results of Studies One and Two highlight the dynamic and complex nature of female sexual arousal. It appears that women have definite cognitive and affective responses to sexual stimuli. The magnitude of these responses may be mediated by a number of factors however, including the intrinsic qualities of the stimulus and the degree to which the woman attends to the stimulus. Both these variables act to either enhance or inhibit the sexual arousal response. There results have important implications for current sexuality literature. While women’s cognitions and emotions in response to erotic film were generally highly correlated, in some instances they differed, warranting their inclusion as separate elements in models of female sexual arousal. Furthermore, it might be suggested that the inclusion of an additional variable – absorption – into current models of female sexual arousal would prove beneficial, aiding researchers to better understand and predict the arousal process. As such, recommendations are made for a revised model of female sexual arousal. In terms of future directions, the results of the present thesis have implications for the treatment of sexual dysfunctions, suggesting that clinicians need to understand the internal and external variables that might contribute to the aetiology and maintenance of their presenting problems.

Development of the multi-scale analysis model to simulate strain localization occurring during material processing

Abstract A detailed description of possibilities given by the developed Cellular Automata—Finite Element (CAFE) multi scale model for prediction of the initiation and propagation of micro shear bands and shear bands in metallic materials subjected to plastic deformation is presented in the work. Particular emphasis in defining the criterion for initiation of micro shear and shear bands, as well as in defining the transition rules for the cellular automata, is put on accounting for the physical aspects of these phenomena occurring in two different scales in the material. The proposed approach led to the creation of the real multi scale model of strain localization phenomena. This model predicts material behavior in various thermo-mechanical processes. Selected examples of applications of the developed model to simulations of metal forming processes, which involve strain localization, are presented in the work. An approach based on the Smoothed Particle Hydrodynamic, which allows to overcome difficulties with remeshing in the traditional CAFE method, is a subject of this work as well. In the developed model remeshing becomes possible and difficulties limiting application of the CAFE method to simple deformation processes are solved. Obtained results of numerical simulaA detailed description of possibilities given by the developed Cellular Automata—Finite Element (CAFE) multi scale model for prediction of the initiation and propagation of micro shear bands and shear bands in metallic materials subjected to plastic deformation is presented in the work. Particular emphasis in defining the criterion for initiation of micro shear and shear bands, as well as in defining the transition rules for the cellular automata, is put on accounting for the physical aspects of these phenomena occurring in two different scales in the material. The proposed approach led to the creation of the real multi scale model of strain localization phenomena. This model predicts material behavior in various thermo-mechanical processes. Selected examples of applications of the developed model to simulations of metal forming processes, which involve strain localization, are presented in the work. An approach based on the Smoothed Particle Hydrodynamic, which allows to overcome difficulties with remeshing in the traditional CAFE method, is a subject of this work as well. In the developed model remeshing becomes possible and difficulties limiting application of the CAFE method to simple deformation processes are solved. Obtained results of numerical simulations are compared with the experimental results of cold rolling process to show good predicative capabilities of the developed model.tions are compared with the experimental results of cold rolling process to show good predicative capabilities of the developed model.

Post processing of the hot torsion test results using a multi-dimensional modelling approach

A model selection scheme was extended to a multi-dimensional representation of the hot torsion test torque, twist and twist rate data to calculate partial derivatives of the torque data with respect to twist and twist rate. These enabled calculation of the instantaneous strain and strain rate hardening indices in the Fields and Backofen method. The concept of an iso-parametric shape function has been borrowed from the finite element method for adding twist rate as a dependant variable to the torque-twist models identified by the model selection scheme. Expressions to calculate the hardening indices, when employing a rational model of torsion data, were derived and presented. Subsequently, the models were used for post processing the data and determining hot strength behaviour, taking into account variations of strain and strain rate hardening indices during the deformation. To substantiate the technique, the hot flow behaviour of API-X70 micro-alloyed steel was determined using a range of hot torsion test data for the material. The flow stress obtained using the instantaneous hardening indices were compared with that obtained by the orthodox technique. For the investigated cases, the onset of dynamic recrystallization (DRX) predicted by the presented technique deviated considerably from those obtained when the average indices were used.

Using the solid-shell element to model the roll forming of large radii profiles

Roll forming is an incremental bending process for forming metal sheet, strip or coiled stock. Although Finite Element Analysis (FEA) is a standard tool for metal forming simulation, it is only now being increasingly used for the analysis of the roll forming process. This is because of the excessive computational time due to the long strip length and the multiple numbers of stands that have to be modelled. Typically a single solid element is used through the thickness of the sheet for roll forming simulations. Recent investigations have shown that residual stresses introduced during steel processing may affect the roll forming process and therefore need to be included in roll forming simulations. These residual stresses vary in intensity through the thickness and this cannot be accounted for by using only one solid element through the material thickness, in this work a solid-shell element with an arbitrary number of integration points has been used to simulate the roll forming process. The system modelled is that of roll forming a V-channel with dual phase DP780 sheet steel. In addition, the influence of other modelling parameters, such as friction, on CPU time is further investigated. The numerical results are compared to experimental data and a good correlation has been observed. Additionally the numerical results show that the CPU time is reduced in the model without friction and that considering friction does not have a significant effect on springback prediction in the numerical analysis of the roll forming process.

Finite element model updating using estimation of distribution algorithm

Finite Element (FE) model updating has been attracting research attentions in structural engineering fields for over 20 years. Its immense importance to the design, construction and maintenance of civil and mechanical structures has been highly recognised. However, many sources of uncertainties may affect the updating results. These uncertainties may be caused by FE modelling errors, measurement noises, signal processing techniques, and so on. Therefore, research efforts on model updating have been focusing on tackling with uncertainties for a long time. Recently, a new type of evolutionary algorithms has been developed to address uncertainty problems, known as Estimation of Distribution Algorithms (EDAs). EDAs are evolutionary algorithms based on estimation and sampling from probabilistic models and able to overcome some of the drawbacks exhibited by traditional genetic algorithms (GAs). In this paper, a numerical steel simple beam is constructed in commercial software ANSYS. The various damage scenarios are simulated and EDAs are employed to identify damages via FE model updating process. The results show that the performances of EDAs for model updating are efficient and reliable.

Structure and mechanical property variations in Mg-Gd-Y-Zn-Zr alloy depending on its composition and processing conditions

An effect of alloying element content on mechanical properties and precipitate formation in Mg-RE alloys was studied for Mg-8Gd-4Y- 1Zn-0.4Zr (wt%) and Mg-10Gd-5Y-1.8Zn-0.4Zr (wt%). It is shown that small variations in the alloying element concentration can be used to manipulate the alloy microstructure and precipitate formation towards eliminating the asymmetry (tension/compression) and anisotropy of yield stress.