Patterns of semantic relations to improve image content search

This paper reports on a study to explore how semantic relations can be used to expand a query for objects in an image. The study is part of a project with the overall objective to provide semantic annotation and search facilities for a virtual collection of art resources. In this study we used semantic relations from WordNet for 15 image content queries. The results show that, next to the hyponym/hypernym relation, the meronym/holonym (part-of) relation is particularly useful in query expansion. We identified a number of relation patterns that improve recall without jeopardising precision.     

Thirty-Something Categorization Results Explained: Selective Attention, Eyetracking, and Models of Category Learning.

An eyetracking study testing D. L. Medin and M. M. Schaffer's (1978) 5-4 category structure was conducted. Over 30 studies have shown that the exemplar-based generalized context model (GCM) usually provides a better quantitative account of 5-4 learning data as compared with the prototype model. However, J. D. Smith and J. P. Minda (2000) argued that the GCM is a psychologically implausible account of 5-4 learning because it implies suboptimal attention weights. To test this claim, the authors recorded undergraduates' eye movements while the students learned the 5-4 category structure. Eye fixations matched the attention weights estimated by the GCM but not those of the prototype model. This result confirms that the GCM is a realistic model of the processes involved in learning the 5-4 structure and that learners do not always optimize attention, as commonly supposed. The conditions under which learners are likely to optimize attention during category learning are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavior of palladium and its impact on intermetallic growth in palladium-coated Cu wire bonding

This paper describes the behavior of palladium in palladium-coated Cu (PdCu) wire bonding and its impact on bond reliability by utilizing transmission electron microscopy (TEM). A Pd layer approximately 80 nm thick, which is coated on the surface of Cu wire, dissolves into the Cu matrix during ball formation (under N₂ gas protection) when the wire tip is melted to form a ball. As a result of dissolving the very thin Pd layer into the ball, Pd is almost undetectable along the entire bond interface between the ball and the Al pad. The behavior of Pd during thermal aging in air, however, is different for central and peripheral interfaces. At the central interface, less than 5 at.% Pd is present after 168 h aging at 175 °C. At the periphery, however, Pd diffuses back and congregates, reaching a level of ～12 at.% after 24 h, and a Pd-rich (Cu,Pd)₉Al₄ layer (>40 at.% Pd) forms after 168 h. Pd acts substitutionally in Cu₉Al₄ but cannot penetrate into the CuAl₂ or CuAl. By comparison of intermetallic thickness and interfacial morphology between PdCu and bare Cu wire bonds, it is concluded that the presence of Pd reduces intermetallic growth rate, and is associated with numerous nanovoids in PdCu bonds.     

Investigation of liquid metal embrittlement of dual phase steel joints by electro-thermomechanical spot-welding simulation

ABSTRACT

A 3D electro-thermomechanical model is established in order to investigate liquid metal embrittlement. After calibration to a dual phase steel of the 1000?MPa tensile strength class, it is used to analyse the thermo-mechanical system of an experimental procedure to enforce liquid metal embrittlement during resistance spot welding. In this procedure, a tensile stress level is applied to zinc coated advanced high strength steel samples during welding. Thereby, liquid metal embrittlement formation is enforced, depending on the applied stress level and the selected material. The model is suitable to determine and visualise the corresponding underlying stresses and strains responsible for the occurrence of liquid metal embrittlement. Simulated local stresses and strains show good conformity with experimentally observed surface crack locations.     

Cartesian machining versus parametric machining: A comparative study

The 'de facto' standard methods of machining sculptured surfaces are by sweeping either the parametric space or the physical space of the workpiece. This paper presents the computational aspects of generating toolpaths for both methods and then compares their performance. For given chord error and scallop height tolerances, the CPU time, the toolpath length, either in cutting or fast moving modes, and the number of cutter retreats are compared for representative surfaces. This comparative study demonstrates the subjective aspects of selecting either machining approaches. It has been found that the only clear difference in performance is in the CPU time, hence the necessity of offering the user the possibility of quantitatively comparing the performance of each approach in order to select the most appropriate.     

Constrained probabilistic multi-objective optimization of shot peening process

Shot peening is a cold working process used for improving the fatigue strength of metallic components. An optimum set of peening parameters must increase the residual compressive stress (RCS), but reduce the surface roughness and cold work for improving the fatigue strength. The optimization is made robust to avoid any unfeasible solution that may arise out of random variations of input variables. The current study uses the well-known Design and Analysis of Computer Experiments (DACE) methodology for optimization, which is better than the conventional Design of Experiments (DoE) approach. It employs a finite element method based unit cell approach to determine the RCS, surface roughness and cold work of a given material. Radial basis functions are used to develop the meta-models. A genetic algorithm (GA) is employed for finding a robust and optimum set of shot peening parameters for a given material. With this approach, the operator will achieve the optimum solution specified by the designer.     

Combining hierarchical and associative gene ontology relations with textual evidence in estimating gene and gene product similarity

Two approaches have recently emerged where the similarity between two genes or gene products is obtained by comparing Gene Ontology (GO) annotations associated with the genes or gene products. One approach captures GO-based similarity in terms of hierarchical relations within each gene subontology, while the other relies on associative relations across the three gene subontologies. We propose a novel methodology where the two approaches can be merged and enriched by textual evidence extracted from biomedical literature with ensuing benefits in coverage and stronger correlation with sequence-based similarity     

Dietary exposure of juvenile rainbow trout (Oncorhynchus mykiss) to 1,2-bis(2,4,6-tribromophenoxy)ethane: bioaccumulation parameters, biochemical effects, and metabolism

Juvenile rainbow trout (Oncorhynchus mykiss) were exposed in the laboratory to an environmentally relevant dose of 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) via their diet for 49 days, followed by 154 days of untreated food to examine bioaccumulation parameters, potential biochemical effects, and metabolic products. There was a linear increase in the amount of BTBPE in fish during the uptake phase of the experiment, and an uptake rate constant of 0.0069 +/- 0.0012 (arithmetic mean +/- 1 x standard error) nmoles per day was calculated. The elimination of BTBPE from the fish obeyed first-order depuration kinetics (r2 = 0.6427, p < 0.001) with a calculated half-life of 54.1 +/- 8.5 days. The derived biomagnification factor of 2.3 +/- 0.9 suggests that this chemical has a high potential for biomagnification in aquatic food webs. Debrominated and hydroxylated metabolites were not detected in liver extracts and suggest that either biotransformation or storage of BTBPE-metabolites in the hepatic system of fish is minor or that our exposure time frame was too short. Similar concentrations of circulating thyroid hormones, liver deiodinase enzyme activity, and thyroid glandular histology suggest that BTBPE is not a potent thyroid axis disruptor.