A review and comparison of strategies for handling missing values in separate-and-conquer rule learning

In this paper, we review possible strategies for handling missing values in separate-and-conquer rule learning algorithms, and compare them experimentally on a large number of datasets. In particular through a careful study with data with controlled levels of missing values we get additional insights on the strategies’ different biases w.r.t. attributes with missing values. Somewhat surprisingly, a strategy that implements a strong bias against the use of attributes with missing values, exhibits the best average performance on 24 datasets from the UCI repository.     

Model-based development of a course of action scheduling tool

This paper shows how a formal method in the form of Coloured Petri Nets (CPNs) and the supporting CPN Tools have been used in the development of the Course of Action Scheduling Tool (COAST). The aim of COAST is to support human planners in the specification and scheduling of tasks in a Course of Action. CPNs have been used to develop a formal model of the task execution framework underlying COAST. The CPN model has been extracted in executable form from CPN Tools and embedded directly into COAST, thereby automatically bridging the gap between the formal specification and its implementation. The scheduling capabilities of COAST are based on state space exploration of the embedded CPN model. Planners interact with COAST using a domain-specific graphical user interface (GUI) that hides the embedded CPN model and analysis algorithms. This means that COAST is based on a rigorous semantical model, but the use of formal methods is transparent to the users. Trials of operational planning using COAST have been conducted within the Australian Defence Force. The work of Lin Zhang was done while he was with the Command and Control Division of the Australian Defence Science and Technology Organisation.     

Development of an optimized refolding process for recombinant Ala-Glu-IGF-1

Denatured and reduced N-terminal extended insulin-like growthfactor-1 (AE-IGF-1) was purified from Escherichia coli extractsand subjected to in vitro folding. The renaturation processwas shown to be a function of the redox potential of the solution.Folding by different methods had no significant effect on therenaturation. A maximal yield of 60% (w/w)was obtained. Thefolded AE-IGF-1 was enzymatically converted to IGF-1. The majorby-product (20% w/w) was identified as scrambled IGF-1. Enzymaticdigestion at alkaline and acidic pH suggested two possible disulphidebond arrangements: (i) Cys⁶–Cys⁴⁷, Cys¹⁸–Cys⁶¹,Cys⁴⁸–Cys⁵²; or (if) Cys⁶–Cys⁵², Cys^l8–Cys⁶¹,Cys⁴⁷ and Cys⁴⁸ being in their reduced forms. Energy minimizationand molecular modelling suggested that the scrambled IGF-1,having reduced cysteines at positions 47 and 48, was the energeticallymost stable conformation of the two.     

Improving the quality of phase maps in phase object digital holographic interferometry by finding the right reconstruction distance

Improved quality of phase maps in pulsed digital holographic interferometry is demonstrated by finding the right reconstruction distance. The objective is to improve the optical phase information when the object under study is a phase object and when it is out of focus, leading to low contrast fringes in the phase map. A numerical refocusing is performed by introducing an ideal lens as a multiplication by a phase field in the Fourier domain, and then a region of maximum speckle correlation is found by comparing undisturbed and disturbed subimages in different refocused imaging planes. After finding the right reconstruction distance, a phase map of high visibility is constructed. By this technique a 30% reduction of the phase error for a flow of helium gas and a 50% reduction of the phase error for a weak thin lens were obtained, which resulted in a significant improvement of the visual appearance of the phase maps.     

Direction sensitive bending sensors based on multi-wall carbon nanotube/epoxy nanocomposites

In the present work, a direction sensitive bending strain sensor consisting of a single block of epoxy/multi-wall carbon nanotube composite was developed. Moreover, the manufacturing could be realized in a straightforward single-step processing route. The directional sensitivity to bending deformations is related to the change in electrical resistance, which becomes positive or negative, depending on the direction of bending deflection. This effect is achieved by generating a gradient in electrical conductivity throughout the material. The resistance versus strain behaviour of these devices is investigated in detail and related to the microstructure of the nanocomposites.     

Recombination dynamics of surface-related excitonic states in single ZnO nanowires

With decreasing diameter the influence of surface-related effects becomes increasingly important for an understanding of the optical properties of semiconductor nanowires. We present time integrated and time resolved photoluminescence studies of single zincoxide nanowires with different diameters. We analyze the changes in the optical spectra for wires with different surface-to-volume ratios, present optical spectra of single wires at different excitation densities, and study the time-resolved dynamics of the surface related and donor-bound exciton related emission lines for a single nanowire at low temperatures.     

Structural densification of lithium phosphoaluminoborate glasses

Lithium aluminoborate glasses have recently been found to undergo dramatic changes in their short-range structures upon compression at moderate pressure (~1 GPa), most notably manifested in an increase in network forming cation coordination number (CN). This has important consequences for their mechanical behavior, and to further understand the structural densification mechanisms of this glass family, we here study the effect of P₂O₅ incorporation in a lithium aluminoborate glass (with fixed Li/Al/B ratio) on the pressure-induced changes in structure, density, and hardness. We find that P₂O₅ addition results in a more open and soft network, with P-O-Al and P-O-B bonding, a slightly smaller fraction of tetrahedral-to-trigonal boron, and an unchanged aluminum speciation. Upon compression, the cation-oxygen CNs of both boron and aluminum increase systemically, whereas the number of bridging oxygens around phosphorous (Qⁿ) decreases. The glasses with higher P₂O₅ content feature a larger decrease in Qⁿ (P) upon compression, which leads to more non-bridging oxygen that in turn fuel the larger increase in CN of B and Al for higher P₂O₅ content. We find that the CN changes of Al and B can account for a large fraction (around 50% at 2 GPa) of the total volume densification and that the extent of structural changes (so-called atomic self-adaptivity) scales well with the extent of volume densification and pressure-induced increase in hardness.     

Language-independent look-ahead for checking multi-perspective declarative process models

Software and Systems Modeling - Declarative process modelling languages focus on describing a process by restrictions over the behaviour, which must be satisfied throughout the whole process...