Active learning for object classification: from exploration to exploitation

Classifying large datasets without any a-priori information poses a problem in numerous tasks. Especially in industrial environments, we often encounter diverse measurement devices and sensors that produce huge amounts of data, but we still rely on a human expert to help give the data a meaningful interpretation. As the amount of data that must be manually classified plays a critical role, we need to reduce the number of learning episodes involving human interactions as much as possible. In addition for real world applications it is fundamental to converge in a stable manner to a solution that is close to the optimal solution. We present a new self-controlled exploration/exploitation strategy to select data points to be labeled by a domain expert where the potential of each data point is computed based on a combination of its representativeness and the uncertainty of the classifier. A new Prototype Based Active Learning (PBAC) algorithm for classification is introduced. We compare the results to other active learning approaches on several benchmark datasets.     

Effect of serum proteins and osteoblasts on the surface transformation of a calcium phosphate coating: a physicochemical and ultrastructural study

We describe a practical method for the analysis of multiple analytes in a single sample. The vehicle for each separate measurement consists of a set of microspheres identifiable by characteristic fluorophores embedded in the particles. The use of robust, bench-top flow cytometers (flow microfluorimeters) for the analysis of the multiple sets of microspheres is facilitated by hardware and software, which acquire the data from the cytometer, classify the microspheres according to sets, and collate measurement information from each microsphere set in real time. This measurement system can analyze up to 64 analytes in a single sample. The advantages of multiplexed assays using flow cytometry include robust measurements, because each microsphere set is measured repeatedly. The advantage of the assay's is consistent with simultaneous measurement of many parameters as well as the speed with which the flow microfluorimeter (cytometer) makes measurements (many hundreds per second). Here, we describe the properties of the microspheres, the calibration of the cytometer, and the influence of the properties of the microspheres on the sensitivity of measurements.     

Gender differences in posttraumatic stress disorder.

One of the most consistent findings in the epidemiology of posttraumatic stress disorder (PTSD) is the higher risk of this disorder in women. Explanations reviewed within a psychobiological model of PTSD suggest that women's higher PTSD risk may be due to the type of trauma they experience, their younger age at the time of trauma exposure, their stronger perceptions of threat and loss of control, higher levels of peritraumatic dissociation, insufficient social support resources, and greater use of alcohol to manage trauma-related symptoms like intrusive memories and dissociation, as well as gender-specific acute psychobiological reactions to trauma. This review demonstrates the need for additional research of the gender differences in posttraumatic stress. Recommendations are made for clinical practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Elektrochemische Rauschmessungen an partiell beschichteten Oberflächen verschiedener Werkstoffe

Electrochemical noise measurements on partly coated surfaces of different materials Defects or for a special function necessary interruptions in the polymer coating on metallic materials are preferred sites of increased corrosion attack. The delamination of coatings originating from those irregularities is of great practical relevance and thus now as before also subject of intensive scientific studies. Apart from already established research methods, the measurement of electrochemical noise offers an additional research method for assessment of delamination and corrosion phenomena around defects in the coating in situ in dependency on the substrate and coating materials, the corrosive agent and environment, as well as on other influencing parameters. In this paper results of such kind of noise measurements on two quite different corrosion systems are presented.     

Anaerobic expression of Escherichia coli succinate dehydrogenase: functional replacement of fumarate reductase in the respiratory chain during anaerobic growth

Succinate-ubiquinone oxidoreductase (SQR) from Escherichia coli is expressed maximally during aerobic growth, when it catalyzes the oxidation of succinate to fumarate in the tricarboxylic acid cycle and reduces ubiquinone in the membrane. The enzyme is similar in structure and function to fumarate reductase (menaquinol-fumarate oxidoreductase [QFR]), which participates in anaerobic respiration by E. coli. Fumarate reductase, which is proficient in succinate oxidation, is able to functionally replace SQR in aerobic respiration when conditions are used to allow the expression of the frdABCD operon aerobically. SQR has not previously been shown to be capable of supporting anaerobic growth of E. coli because expression of the enzyme complex is largely repressed by anaerobic conditions. In order to obtain expression of SQR anaerobically, plasmids which utilize the PFRD promoter of the frdABCD operon fused to the sdhCDAB genes to drive expression were constructed. It was found that, under anaerobic growth conditions where fumarate is utilized as the terminal electron acceptor, SQR would function to support anaerobic growth of E. coli. The levels of amplification of SQR and QFR were similar under anaerobic growth conditions. The catalytic properties of SQR isolated from anaerobically grown cells were measured and found to be identical to those of enzyme produced aerobically. The anaerobic expression of SQR gave a greater yield of enzyme complex than was found in the membrane from aerobically grown cells under the conditions tested. In addition, it was found that anaerobic expression of SQR could saturate the capacity of the membrane for incorporation of enzyme complex. As has been seen with the amplified QFR complex, E. coli accommodates the excess SQR produced by increasing the amount of membrane. The excess membrane was found in tubular structures that could be seen in thin-section electron micrographs.     

Surface oxide films on Aluminum bondpads: Influence on thermosonic wire bonding behavior and hardness

Using indentation testing, wire bond tests and electron microscopy, the influence of increased oxide films on Al metallization surfaces on the wire bonding behavior and hardness was investigated. Oxide film thickness values larger than about 20 nm obstruct the bond contact and resulted in a poor bonding quality. The presence of such films causes also a hardness increase which can be detected by current sensitive indentation test methods. Therefore, an improved indentation testing technique can be applied during the quality control of bondpad metallizations prior to wire bonding.     

Theoretical and experimental investigations on the influence of the microscopic anisotropic material properties of gear teeth on their macroscopic behavior

Innovative cold rolling technologies are important future production methods to gain more resource efficiency producing gears. Through current research at the Fraunhofer Institute for Machine Tools and Forming Technology (IWU), it is possible to produce running gears for use in vehicle transmissions by this method.The paper contends theoretical and experimental investigations on cold rolled gears to determine their properties in detail. The theoretical principles of material anisotropy following cold forming processes as well as the results of investigations on gear teeth are discussed. Different calculation methodologies to compute the efficient elastic behavior of an anisotropic material area are compared by applying them to measurement data of an Electron Backscatter Diffraction (EBSD). Furthermore, methods to simulate the rolling process are described and applied to the investigated gear. It is shown that the production method can have an effect on the elastic material behavior of gear teeth.     

Relation of α2-Antiplasmin Genotype and Genetic Determinants of Fibrinogen Synthesis and Fibrin Clot Formation with Vascular Endothelial Growth Factor Level in Axial Spondyloarthritis

Objective: Coagulation and fibrinolysis are interrelated with the expression of vascular endothelial growth factor (VEGF), which frequently is increased in axial spondyloarthritis (axSpA). We tested whether (i) α₂-antiplasmin (A2AP) Arg6Trp, (ii) fibrinogen, factor XIII A-subunit or B-subunit genotypes are associated with VEGF levels and assessed whether the known association between elevated VEGF and radiographic spinal progression in axSpA depends on genetic background. Methods: One hundred and eighty-six axSpA patients from the German Spondyloarthritis Inception Cohort were genotyped, characterized for VEGF levels, and statistically analyzed. The association between VEGF and radiographic spinal progression was assessed in dependence on genetic background in stratified analyses. Results: A2AP 6Trp carriage was associated with VEGF elevation (OR: 2.37, 95% CI: 1.06–5.29) and VEGF levels (6Trp, 455 ± 334 pg/mL; 6Arg/Arg, 373 ± 293 pg/mL; p < 0.008). Association between elevated VEGF and radiographic spinal progression in axSpA (OR: 3.11, 95% CI: 1.02–8.82) depended remarkably on the fibrinogen (FGA) genotype. When considering axSpA patients with elevated VEGF, in FGA rs6050A>G wild types, 42.1% of patients (8 of 19) progressed, while in G-allele carriers, no radiographic progression happened (0 of 13) (p < 0.04). Conclusions: The A2AP Arg6Trp genotype seems to influence VEGF levels in axSpA. The predictive value of VEGF elevations in respect of radiographic spinal progression in axSpA depends on FGA genotypes.