1,818 research outputs found

    Intelligent computational sketching support for conceptual design

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    Sketches, with their flexibility and suggestiveness, are in many ways ideal for expressing emerging design concepts. This can be seen from the fact that the process of representing early designs by free-hand drawings was used as far back as in the early 15th century [1]. On the other hand, CAD systems have become widely accepted as an essential design tool in recent years, not least because they provide a base on which design analysis can be carried out. Efficient transfer of sketches into a CAD representation, therefore, is a powerful addition to the designers' armoury.It has been pointed out by many that a pen-on-paper system is the best tool for sketching. One of the crucial requirements of a computer aided sketching system is its ability to recognise and interpret the elements of sketches. 'Sketch recognition', as it has come to be known, has been widely studied by people working in such fields: as artificial intelligence to human-computer interaction and robotic vision. Despite the continuing efforts to solve the problem of appropriate conceptual design modelling, it is difficult to achieve completely accurate recognition of sketches because usually sketches implicate vague information, and the idiosyncratic expression and understanding differ from each designer

    Shape matching and clustering

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    Generalising knowledge and matching patterns is a basic human trait in re-using past experiences. We often cluster (group) knowledge of similar attributes as a process of learning and or aid to manage the complexity and re-use of experiential knowledge [1, 2]. In conceptual design, an ill-defined shape may be recognised as more than one type. Resulting in shapes possibly being classified differently when different criteria are applied. This paper outlines the work being carried out to develop a new technique for shape clustering. It highlights the current methods for analysing shapes found in computer aided sketching systems, before a method is proposed that addresses shape clustering and pattern matching. Clustering for vague geometric models and multiple viewpoint support are explored

    Calvin’s sudden conversion (Subita Conversio) and its historical meaning ‘cor meum tibi offero, prompte et sincere’

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    In Calvin research of the Twentieth Century, different approaches towards the question about Calvin’s ‘conversion’, as mentioned in the introduction to his commentary on the Psalms, have been followed. In this article a number of these approaches are discussed, as well as certain other issues, which should be taken into account. After a discussion of these issues the conclusion is drawn that Calvin’s conversion was not the product of a gradual recognition and human decision, but an event of a decisive regeneration, resulting in true and evangelical faith under the sovereign guidance of God. Calvin’s thought on the sovereignty of God provided the guiding principle for the Reformed faith. Therefore, Calvin’s conversion was more than the conversion of an individual. It was rather a matrix for the formation of the Reformed faith and the Reformed and Presbyterian Churches. It was also the guidance and special providence of God, completing the Reformation

    Managing Climatic Risks to Combat Land Degradation and Enhance Food security: Key Information Needs

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    This paper discusses the key information needs to reduce the negative impacts of weather variability and climate change on land degradation and food security, and identifies the opportunities and barriers between the information and services needed. It suggests that vulnerability assessments based on a livelihood concept that includes climate information and key socio-economic variables can overcome the narrow focus of common one-dimensional vulnerability studies. Both current and future climatic risks can be managed better if there is appropriate policy and institutional support together with technological interventions to address the complexities of multiple risks that agriculture has to face. This would require effective partnerships among agencies dealing with meteorological and hydrological services, agricultural research, land degradation and food security issues. In addition a state-of-the-art infrastructure to measure, record, store and disseminate data on weather variables, and access to weather and seasonal climate forecasts at desired spatial and temporal scales would be needed

    Topological Charge Fluctuations and Low-Lying Dirac Eigenmodes

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    We discuss the utility of low-lying Dirac eigenmodes for studying the nature of topological charge fluctuations in QCD. The implications of previous results using the local chirality histogram method are discussed, and the new results using the overlap Dirac operator in Wilson gauge backgrounds at lattice spacings ranging from a~0.04 fm to a~0.12 fm are reported. While the degree of local chirality does not change appreciably closer to the continuum limit, we find that the size and density of local structures responsible for chiral peaking do change significantly. The resulting values are in disagreement with the assumptions of the Instanton Liquid Model. We conclude that the fluctuations of topological charge in the QCD vacuum are not locally quantized.Comment: 3 pages, 4 figures, Lattice2001(confinement

    Bogomol'nyi equations for solitons in Maxwell-Chern-Simons gauge theories with the magnetic moment interaction term

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    Without assuming rotational invariance, we derive Bogomol'nyi equations for the solitons in the abelian Chern-Simons gauge theories with the anomalous magnetic moment interaction. We also evaluate the number of zero modes around a static soliton configuration.Comment: 9 pages, Revtex, SNUTP-94/6

    Rheological evaluation of the fabrication parameters of cellulose acetate butyrate membrane on CO2/N2 separation performance

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    The rise in emission of greenhouse gases (GHGs) mainly carbon dioxide (CO2) in recent years due to rapid development of modern civilisation, has been listed as the primary contributor to global warming. To address this global issue, membrane technology was applied and developed intensively because of its superior performance in terms of efficiency and economic advantages. In this study, the cellulose acetate butyrate (CAB) polymer was selected as the polymer matrix material since it exhibited excellent film-forming properties. In addition, the wet-phase inversion technique was adopted to synthesise the membrane based on different casting conditions. The optimum outcomes of the fabrication conditions were then characterised with the scanning electron micrograph (SEM) to determine the best CAB membrane for CO2/N2 separation. The results showed that CAB-70000 fabricated with 4 wt% of CAB polymer concentration, casting thickness of 250 µm, solvent evaporation time of 5 minutes, and 30 minutes of solvent exchange for isopropyl alcohol and n-hexane, exhibited the best gas separation performance. Further, CAB-70000 showed an average selectivity of 6.12 ± 0.09 and permeance up to 227.95 ± 0.39 GPU for CO2 and 37.28 ± 0.54 GPU for N2, respectively. In summary, this study is expected to show a detailed outline of the future direction and perspective of the novel CAB polymeric membrane that is suitable to be applied in the industry, and serves as an insight for researchers and manufacturers working in the related field of gas separation

    Low-dimensional long-range topological structure in the QCD vacuum

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    Lattice topological charge associated with Ginsparg-Wilson fermions exhibits generic topological stability over quantum ensemble of configurations contributing to the QCD path integral. Moreover, the underlying chiral symmetry leads to the suppression of ultraviolet noise in the associated topological charge densities ("chiral smoothing"). This provides a solid foundation for the direct study of the role of topological charge fluctuations in the physics of QCD vacuum. Using these tools it was recently demonstrated that: (a) there is a well-defined space-time structure (order) in topological charge density (defined through overlap fermions) for typical configurations contributing to QCD path integral; (b) this fundamental structure is low-dimensional, exhibiting sign-coherent behavior on subsets of dimension less than four and not less than one; (c) the structure has a long-range global character (spreading over maximal space-time distances) and is built around the locally one-dimensional network of strong fields (skeleton). In this talk we elaborate on certain aspects and implications of these results.Comment: 3 pages, 1 figure; Lattice2003(topology

    Lateral Size and Thickness Dependence in Ferroelectric Nanostructures Formed by Localized Domain Switching

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    Ferroelectric nanostructures can be formed by local switching of domains using techniques such as piezo-force microscopy (PFM). Understanding lateral size effects is important to determine the minimum feature size for writing ferroelectric nanostructures. To understand these lateral size effects, we use the time-dependent-Ginzburg-Landau equations to simulate localized switching of domains for a PFM type and parallel-plate capacitor configurations. Our investigations indicate that fringing electric fields lead to switching via 90 deg domain wedge nucleation for thicker films while at smaller thicknesses, the polarization switches directly by 180 deg rotations. The voltage required to switch the domain increases by decreasing the lateral size and at very small lateral sizes the coercive voltage becomes so large that it becomes virtually impossible to switch the domain. In all cases, the width of the switched region extends beyond the electrodes, due to fringing.Comment: 21 pages, 11 figure

    Effects of reducing dietary crude protein and metabolic energy in weaned piglets

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    The objective of this experiment was to determine the effects of a pure reduction in the dietary crude protein (CP) and metabolic energy (ME) contents on growth performance, nutrient digestibility, blood profile, faecal microflora and odour gas emission in weaned pigs. A total of 80 weaned piglets ((Landrace × Yorkshire) × Duroc) with a mean initial bodyweight (BW) of 6.8 ± 0.5 kg were randomly allotted to four treatments with four replicate pens of five piglets per pen (based on average BW) for 45 days. The dietary treatments consisted of i) CON: basal diet; ii) LME: reduction of 10% of ME in basal diet; iii) LCP: reduction of 10% of CP in basal diet; iv) MECP: reduction of 10% of CP and 10% of ME in basal diet. During the experimental period, average daily feed intake (ADFI) improved in piglets fed the LME and LCP diets, compared with those fed the CON diets. Average daily gain (ADG) and gain to feed (G : F) ratio decreased in piglets fed LCP, LME, and MECP diet, when compared with those fed the CON diet. However, during the total experimental period, ADG and G : F ratio were not affected by dietary treatment. With regard to nutrient digestibility, apparent total track digestibility (ATTD) of CP was not affected by experimental diets. The concentration of blood urea nitrogen (BUN) in blood decreased more in piglets fed LME, LCP, and MECP than those fed the CON diet. The emissions of ammonia (NH3), hydrogen sufide (H2S), and volatile fatty acids (VFAs) were lower in piglets fed LME, LCP, and MECP diet than those fed the CON diet. In conclusion, these results indicate that reduction in dietary CP and ME content did not decrease growth performance and nutrient digestibility, and they increased positive effects such as BUN and gas emission reduction.Keywords: Blood profile, digestibility, growth performance, odour emission, pi
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