Statistical properties of the rWG(J) index of agreement.

L. R. James, R. G. Demaree, and G. Wolf (1984) introduced rwg(J) to estimate interrater agreement for a group. This index is calculated by comparing an observed group variance with an expected random variance. As researchers have gained experience using this index, several questions have arisen. What are the consequences of replacing values beyond the unit interval by 0? What is the dependence of rwg(J) on the group size? The authors' simulations show that a positive bias is caused by the truncation, but for large population values of rwg(J) it is negligible. Also, in this case, the group size has no effect on the expected value of rwg(J). For inference on rwg(J), researchers can exploit the availability of computers to simulate data from the hypothesized distribution and then compare the simulation results for rwg(J) with the actual values. In addition, it is shown how the bootstrap method can be used for comparing the indices of 2 groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enantiomeric Control of Intrinsically Chiral Nanocrystals

The chiral aspect of inorganic crystals that crystallize in chiral space groups has been largely ignored until recently, partly due to difficulties in characterizing the chiroptical properties of bulk crystals, and also due to the difficulty in separating (sub)micrometer-scale chiral crystal enantiomers. In recent years, the colloidal synthesis of intrinsically chiral nanocrystals (NCs) of several chiral inorganic compounds with significant enantiomeric excess has been demonstrated. This is achieved through the use of chiral molecular ligands, which bind to the atomic/ionic components of the crystals, preferentially forming one crystal enantiomorph. Here, recent progress on several aspects of these NCs is described, including the connection between ligand structure and its ability to direct NC handedness, chiral amplification in the synthesis leading to enantiopure NC samples, spontaneous symmetry breaking, the formation of NCs with chiral shapes, the connection between lattice and shape chirality and mixed contributions of atomic-scale and shape chirality to the chiroptical properties.     

Adaptive shape prior for recognition and variational segmentation of degraded historical characters

We propose a variational method for model based segmentation of gray-scale images of highly degraded historical documents. Given a training set of characters (of a certain letter), we construct a small set of shape models that cover most of the training set's shape variance. For each gray-scale image of a respective degraded character, we construct a custom made shape prior using those fragments of the shape models that best fit the character's boundary. Therefore, we are not limited to any particular shape in the shape model set. In addition, we demonstrate the application of our shape prior to degraded character recognition. Experiments show that our method achieves very accurate results both in segmentation of highly degraded characters and both in recognition. When compared with manual segmentation, the average distance between the boundaries of respective segmented characters was 0.8 pixels (the average size of the characters was 70*70 pixels).     

Disciplined and free-spirited: ‘Time-out behaviour’ at the Agile conference

In this article we observe and try to understand a peculiar duality in the agile community, whereby on the one hand, we see a serious professional community working hard to improve the quality of software products and submitting to the strictest discipline of high professional standards, while on the other hand, in its conferences, we see the same community adopting a playful free-spirited stance. Invoking an anthropological perspective, we propose that both the serious professional aspects and the playful free-spirited atmosphere at the conference, as well as the connection between the two, can all be seen to emerge from the fundamental principles of the agile community as expressed by its Manifesto.     

Case-based Sentencing Using a Tree of Legal Concepts

The Judge's Apprentice is a case-based decision support system implemented and intended for use in Israeli criminal law to aid sentencing in cases of either robbery or rape. The system uses a sentencing tree, which is a hierarchical classification of 371 legal concepts relevant to criminal sentencing. Each leaf in this tree represents an index, which can be input for any case. The indexes are important for determining index similarity in the retrieval process and for computation of the proposed sentence. After retrieval of suitable cases and selection of the best case, we use a case-based quantitative evaluation as a formula for computing a verdict for the case at hand.     

Modeling Hydrogen Sulfide Emission Rates in Gravity Sewage Collection Systems

The factors affecting sulfide buildup in gravity sewers are complex, consisting of biological and physical processes, both in the aqueous and the gas phases of the sewer. The rate of each of these processes varies (among other parameters) according to flow characteristics, temperature, and pH. Under fast and turbulent flow conditions, the stripping of hydrogen sulfide into the gas phase may become the dominant process. The paper presents a semiempirical approach to the problem of quantifying hydrogen sulfide emission rates in sewers. Kinetics of hydrogen sulfide emission as a function of hydraulic parameters was measured in the laboratory using methods adopted from flocculation theory. A flocculation unit was used to impart a selected velocity gradient (G) into the water, and sulfide concentration was measured with time. The process was repeated for a number of G values. Regression analysis was then used to fit the rate of hydrogen sulfide emission equation against G. An equation was developed linking G to HL (head loss) in sewers assuming plug flow conditions. The hydraulic model and the kinetic model were linked (via G) to give the desired rate equation for hydrogen sulfide emission along a sewer line. The model was used to predict H2S emission from a uniform flow sewer and the effect of parameters such as pH, sewer slope and degree of fullness was studied. As expected, results show that low pH, high slope, and low degree of fullness enhance emission rates. Reasonable agreement was attained when the model output was compared with measured results from a field test sewer in Virginia, South Africa, under conditions where sulfide stripping was the rate-dominant process.     

Sampled-data H8 state-feedback control of systems with state delays

Sliding mode based feedback control has long been recognized as a powerful, yet easy-to-implement, control method to counteract non-vanishing external disturbances and unmodelled dynamics. Recently, research attention has focused on the development of sliding mode feedback control methods for various classes of infinite-dimensional systems. However, the existing methods are based on the assumption that distributed sensing and actuation is available, which significantly restricts their applicability to distributed process control applications. In this work, a sliding mode output feedback control method is developed for a class of linear infinite-dimensional systems with finite-dimensional unstable part using finite-dimensional sensing and actuation. Modal decomposition is initially used to decompose the original infinite-dimensional system into an interconnection of a finite-dimensional (possibly unstable) system and an infinite-dimensional stable system. Then, a sliding mode-based stabilizing state feedback controller is constructed on the basis of the finite-dimensional system. Subsequently, an infinite-dimensional Luenberger state observer, which utilizes a finite number of measurements, is constructed to provide estimates of the state of the infinite-dimensional system. Finally, an output feedback controller design is completed by coupling the infinite-dimensional Luenberger state observer and the sliding mode-based state feedback controller. Implementation, performance and robustness issues of the sliding-mode output feedback controller are illustrated in a simulation study of a distributed parameter system governed by the linearization around the spatially-uniform steady-state solution of the Kuramoto–Sivashinsky partial differential equation with periodic boundary conditions.     

“Andromaly”: a behavioral malware detection framework for android devices

This article presents Andromaly—a framework for detecting malware on Android mobile devices. The proposed framework realizes a Host-based Malware Detection System that continuously monitors various features and events obtained from the mobile device and then applies Machine Learning anomaly detectors to classify the collected data as normal (benign) or abnormal (malicious). Since no malicious applications are yet available for Android, we developed four malicious applications, and evaluated Andromaly’s ability to detect new malware based on samples of known malware. We evaluated several combinations of anomaly detection algorithms, feature selection method and the number of top features in order to find the combination that yields the best performance in detecting new malware on Android. Empirical results suggest that the proposed framework is effective in detecting malware on mobile devices in general and on Android in particular.     

Overview of the Plasma Science and Innovation Center (PSI – Center)

The principal goal of the Plasma Science and Innovation Center (PSI – Center) is to achieve significantly improved computational predictive capability for smaller-scale devices. This is being accomplished through the refinement of existing computational tools through adding sufficient physics modeling, boundary conditions, and geometric capabilities while benchmarking results against experimental data. The work emphasizes the modeling needs of emerging concept (EC) experiments, but improved simulation capabilities for all innovative confinement concepts (ICC) are expected. A special emphasis is placed on physics effects that may extend beyond the standard analysis applied to the mainline programs.