Vision and action

Our work on active vision has recently focused on the computational modelling of navigational tasks, where our investigations were guided by the idea of approaching vision for behavioural systems in the form of modules that are directly related to perceptual tasks. These studies led us to branch in various directions and inquire into the problems that have to be addressed in order to obtain an overall understanding of perceptual systems. In this paper, we present our views about the architecture of vision systems, about how to tackle the design and analysis of perceptual systems, and promising future research directions. Our suggested approach for understanding behavioural vision to realize the relationships of perception and action builds on two earlier approaches, the Medusa philosophy¹ and the Synthetic approach². The resulting framework calls for synthesizing an artificial vision system by studying vision competences of increasing complexity and, at the same time, pursuing the integration of the perceptual components with action and learning modules. We expect that computer vision research in the future will progress in tight collaboration with many other disciplines that are concerned with empirical approaches to vision, i.e. the understanding of biological vision. Throughout the paper, we describe biological findings that motivate computational arguments which we believe will influence studies of computer vision in the near future.     

How do humans inspect BPMN models: an exploratory study

Even though considerable progress regarding the technical perspective on modeling and supporting business processes has been achieved, it appears that the human perspective is still often left aside. In particular, we do not have an in-depth understanding of how process models are inspected by humans, what strategies are taken, what challenges arise, and what cognitive processes are involved. This paper contributes toward such an understanding and reports an exploratory study investigating how humans identify and classify quality issues in BPMN process models. Providing preliminary answers to initial research questions, we also indicate other research questions that can be investigated using this approach. Our qualitative analysis shows that humans adapt different strategies on how to identify quality issues. In addition, we observed several challenges appearing when humans inspect process models. Finally, we present different manners in which classification of quality issues was addressed.     

Calculated Nanocube Vacancy Formation Energy and Cohesion Energy at 0 K

Nanoparticles of face‐centered cubic Cu are modeled using the Sutton–Chen potential. Shapes ranging from perfect cubes through to octahedrons are modeled and characterized. Bulk properties, surface energies, vacancy formation energy, E_v, and cohesive energies, E_coh, are investigated for particles simulated to up to 5 nm in diameter. Below the subsurface layers, particles larger than 1 nm diameter are compared well to bulk. Of the different shapes, rhombicuboctahedrons are both more stable and have more reactive surfaces. As E_v is dependent on surface orientation, there is a little correlation with size and E_v is mostly dependent on nanoparticle shape. E_coh is not as dependent on surface orientation and shows both size and shape dependency.     

Understanding Declare models: strategies,pitfalls, empirical results

Declarative approaches to business process modeling are regarded as well suited for highly volatile environments, as they enable a high degree of flexibility. However, problems in understanding and maintaining declarative process models often impede their adoption. Likewise, little research has been conducted into the understanding of declarative process models. This paper takes a first step toward addressing this fundamental question and reports on an empirical investigation consisting of an exploratory study and a follow-up study focusing on the system analysts’ sense-making of declarative process models that are specified in Declare. For this purpose, we distributed real-world Declare models to the participating subjects and asked them to describe the illustrated process and to perform a series of sense-making tasks. The results of our studies indicate that two main strategies for reading Declare models exist: either considering the execution order of the activities in the process model, or orienting by the layout of the process model. In addition, the results indicate that single constraints can be handled well by most subjects, while combinations of constraints pose significant challenges. Moreover, the study revealed that aspects that are similar in both imperative and declarative process modeling languages at a graphical level, while having different semantics, cause considerable troubles. This research not only helps guiding the future development of tools for supporting system analysts, but also gives advice on the design of declarative process modeling notations and points out typical pitfalls to teachers and educators of future systems analysts.     

Compensation effects in the thermoxidative decomposition of polymers

Summary Are presented some aspects of the non-isothermal kinetics of the thermoxidative decomposition of poly(methylmethacrylate), poly(vinylchloride), poly(vinylacetate) and poly(vinylalcohol). Both the apparent activation energies and the pre-exponential factor depend on conversion and exhibit a pseudo-compensation effect.     

Modification of cellulose/chitin mix fibers with N‐isopropylacrylamide and poly(N‐isopropylacrylamide) under cold plasma conditions

A two‐step grafting procedure was applied to cellulose/chitin (CC) mix fibers, namely: activation under the action of cold plasma discharges, followed by reaction with N‐isopropylacrylamide (NIPAAm) and poly(N‐isopropylacrylamide) (PNIPAAm) to obtain fibers with responsiveness to external stimuli. The graft samples were characterized using attenuated total reflection Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction, scanning electron microscopy coupled with energy‐dispersive X‐ray microanalysis and antimicrobial testing. All obtained results confirm the morphological and structural changes after plasma treatment which determine the modification of cellulose fiber properties. It was estimated from XPS data that the degrees of modification/grafting were about 23% for CC/NIPAAm and 13% for CC/PNIPAAm. Such treatment could be transferred to practical technologies, particularly in textile applications and special applications in the medical field. Copyright © 2012 Society of Chemical Industry     

Current Perspectives on Synthetic Compartments for Biomedical Applications

Nano- and micrometer-sized compartments composed of synthetic polymers are designed to mimic spatial and temporal divisions found in nature. Self-assembly of polymers into compartments such as polymersomes, giant unilamellar vesicles (GUVs), layer-by-layer (LbL) capsules, capsosomes, or polyion complex vesicles (PICsomes) allows for the separation of defined environments from the exterior. These compartments can be further engineered through the incorporation of (bio)molecules within the lumen or into the membrane, while the membrane can be decorated with functional moieties to produce catalytic compartments with defined structures and functions. Nanometer-sized compartments are used for imaging, theranostic, and therapeutic applications as a more mechanically stable alternative to liposomes, and through the encapsulation of catalytic molecules, i.e., enzymes, catalytic compartments can localize and act in vivo. On the micrometer scale, such biohybrid systems are used to encapsulate model proteins and form multicompartmentalized structures through the combination of multiple compartments, reaching closer to the creation of artificial organelles and cells. Significant progress in therapeutic applications and modeling strategies has been achieved through both the creation of polymers with tailored properties and functionalizations and novel techniques for their assembly.     

Antithrombin Activity and Association with Risk of Thrombosis and Mortality in Patients with Cancer

Venous and arterial thromboembolism (VTE/ATE) are common complications in cancer patients. Antithrombin deficiency is a risk factor for thrombosis in the general population, but its connection to risk of cancer-associated thrombosis is unclear. We investigated the association of antithrombin activity levels with risk of cancer-associated VTE/ATE and all-cause mortality in an observational cohort study including patients with cancer, the Vienna Cancer and Thrombosis Study. In total, 1127 patients were included (45% female, median age: 62 years). Amongst these subjects, 110 (9.7%) patients were diagnosed with VTE, 32 (2.8%) with ATE, and 563 (49.9%) died. Antithrombin was not associated with a risk of VTE (subdistribution hazard ratio (SHR): 1.00 per 1% increase in antithrombin level; 95% CI: 0.99–1.01) or ATE (SHR: 1.00; 95% CI: 0.98–1.03). However, antithrombin showed a u-shaped association with the risk of all-cause death, i.e., patients with very low but also very high levels had poorer overall survival. In the subgroup of patients with brain tumors, higher antithrombin levels were associated with ATE risk (SHR: 1.02 per 1% increase; 95% CI: 1.00–1.04) and mortality (HR: 1.01 per 1% increase; 95% CI: 1.00–1.02). Both high and low antithrombin activity was associated with the risk of death. However, no association with cancer-associated VTE and ATE across all cancer types was found, with the exception of in brain tumors.     

Kinetic Study of Heterogeneously Catalyzed Glucose Oxidation in a Stirred Cell

Liquid phase oxidation of glucose to gluconic acid using Bi promoted Pd catalysts was studied in a stirred cell. Gas‐liquid mass transfer limitations are observed at lower but not at higher rotational speeds. The conversion and the deactivation of the Pd catalyst depend on the O₂ concentration in the liquid phase. With decreasing glucose concentration, the reaction rate decreases leading to higher oxygen concentration in the liquid, which deactivates the catalyst due to over‐oxidation. Severe mass transfer limitations even at low Pd loadings could be attributed to intraparticle or liquid‐to‐solid mass transfer.