Designing wrapper components for e-services in integrating heterogeneous systems

Component-based approaches are becoming more and more popular to support Internet-based application development. Different component modeling approaches, however, can be adopted, obtaining different abstraction levels (either conceptual or operational). In this paper we present a component-based architecture for the design of e-applications, and discuss the concept of wrapper components as building blocks for the development of e-services, where these services are based on legacy systems. We discuss their characteristics and their applicability in Internet-based application development. Received: 30 October 2000 / Accepted: 9 January 2001 Published online: 28 June 2001     

Trusted Computing Platform Alliance

An industry consortium focused on ensuring that all PCs are secure for electronic business transactions has announced the release of its first version specification. The Trusted Computing Platform Alliance (TCPA), backed by founding members Compaq, Microsoft, Hewlett-Packard, IBM and Intel, said that the specification will adopt the combination of a hardware and a software approach, which includes a security chip that encrypts data whether filed locally, or sent over the Internet by E-mail.     

AutoTutor: Incorporating Back-Channel Feedback and Other Human-Like Conversational Behaviors into an Intelligent Tutoring System

This paper describes our recent attempts to incorporate human-like conversational behaviors into the dialog moves delivered by an animated pedagogical agent that simulates human tutors. We first present a brief overview of the modules comprising AutoTutor, an intelligent tutoring system. The second section describes a set of conversational behaviors that are being incorporated into AutoTutor. The behaviors of interest involve variations in intonation, head movements, arm and hand movements, facial expressions, eye blinking, gaze direction, and back-channel feedback. The final section presents a recent empirical study concerned with back-channel feedback events during human-to-human tutoring sessions. The back-channel feedback events emitted by tutors are mostly positive (63%), mostly verbal (77%), and immediately follow speech-act boundaries or noun-phrase boundaries (83%). Tutors also deliver back-channelevents at a very high rate when students are emitting dialog, about 13 events per minute. Conversely, 88% of students' back-channel feedback events are head nods, and they occur at unbounded locations (63%).     

Genetic Threading

The biological function of proteins is dependent, to a large extent, on their native three dimensional conformation. Thus, it is important to know the structure of as many proteins as possible. Since experimental methods for structure determination are very tedious, there is a significant effort to calculate the structure of a protein from its linear sequence. Direct methods of calculating structure from sequence are not available yet. Thus, an indirect approach to predict the conformation of protein, called threading, is discussed. In this approach, known structures are used as constraints, to restrict the search for the native conformation. Threading requires finding good alignments between a sequence and a structure, which is a major computational challenge and a practical bottleneck in applying threading procedures. The Genetic Algorithm paradigm, an efficient search method that is based on evolutionary ideas, is used to perform sequence to structure alignments. A proper representation is discussed in which genetic operators can be effectively implemented. The algorithm performance is tested for a set of six sequence/structure pairs. The effects of changing operators and parameters are explored and analyzed.     

Visual lobe shape and search performance for targets of different difficulty

In quantitative models of visual search it has usually been assumed that visual lobe area shape was sufficiently regular to be approximated by a circle or ellipse. However, the irregularities in visual lobe shapes that have been found in studies involving extensive lobe mapping have suggested that lobe shape may have important implications for visual search performance and for the accuracy of mathematical models used for performance prediction. However, no systematic research on the relationship between the shape aspect of visual lobes and search performance seems to have been carried out and no comparisons of visual lobe shape characteristics under the effect of target difficulty have been reported. The current study was conducted to achieve two major objectives in two experiments. Experiment 1 used two different targets (letter 'O' and letter 'Y') to map the visual lobes of subjects in order to provide a systematic and quantitative comparison of lobe shape characteristics and experiment 2 was to investigate the correlation of visual lobe shape characteristics with visual search time under the effect of target difficulty. The visual lobes of 28 subjects were mapped on 24 imaginary and regularly spaced meridians originating from the centre of the visual field to resemble the full field mapping situation. Five categories of shape indices, viz. roundness, boundary smoothness, symmetry, elongation and shape regularity were investigated. The results of this study demonstrated that the visual lobe shapes of subjects elongate horizontally with medium level of roundness, high levels of boundary smoothness, symmetry and regularity for an easy target (O) against a homogeneous background of 'X's. When a difficult target (Y) was used, the visual lobes of the subjects were still elongated horizontally but to a smaller extent and with a low level of roundness, medium level of boundary smoothness and regularity and a similar high level of symmetry to the easy target. Moreover, significant correlations between shape indices and visual search time were found, suggesting mathematical models for predicting search time should not merely rely on area but also should consider visual lobe shape indices. Finally, a universal mathematical model containing several visual lobe shape indices was developed, which was applicable in the prediction of visual search time for a range of similar search tasks.     

Exploring the Interaction between Java's Implicitly Thrown Exceptions and Instruction Scheduling

The frequent occurrence of implicitly thrown exceptions poses one of the challenges present in a Java compiler. Not only do these implicitly thrown exceptions directly affect the performance by requiring explicit checks, they also indirectly impact the performance by restricting code movement in order to satisfy the precise exception model in Java. In particular, instruction scheduling is one transformation that is restricted by implicitly thrown exceptions due to the heavy reliance on reordering instructions to exploit maximum hardware performance. The goal of this study is two-fold: first, investigate the degree to which implicitly thrown exceptions in Java hinder instruction scheduling, and second, find new techniques for allowing more efficient execution of Java programs containing implicitly thrown exceptions. Experimental results show that with aggressive scheduling techniques, such as superblock scheduling, the negative performance impact can be greatly reduced.     

Passivation of pyrite due to surface treatment

Two samples of naturally occurring pyrite were treated with acetyl acetone, silanes, humic acids, lignin-NaOH mixture, and oxalic acid. The corrosion rate of pyrite was observed to decrease significantly due to the surface treatment by the chemicals used in this study. Surface characterization methods indicate that phenyl triacetoxy silane forms a passive coating a few Angstroms thick on the pyrite, thus preventing its dissolution in 1M H₂SO₄.     

The deep waters of land reform: land,water and conservation area claims in Limpopo Province,Olifants Basin,South Africa

Through investigating the reactions of commercial farmers to land and water reforms in the Trichardtsdal-Ofcolaco area, Limpopo Province, Olifants Basin, South Africa, from 1997 to 2006, it is shown that water claims are key to land redistribution processes, and that commercial farmers make strategic use of arguments for nature conservation and ecological stewardship to defend their claims to water. Given these observations, caution is warranted with respect to the implementation of land and water reforms as separate policy packages; it may be more effective to design water and conservation policies as an integral part of land reform programmes.     

Using digital technologies to redress inequities for English language learners in the English speaking mathematics classroom

This study examined the question, ‘What is the impact of a digital math intervention on secondary ELL students’ mathematical capabilities and perceptions of their future possibilities?’ The hypothesis was that through its direct effect on increasing students’ math ability and its indirect effect on increasing students’ perceived math self-efficacy, the digital intervention affects students’ perceptions of their functionings and future possibilities. A path analysis, with qualitative data nested into the design, was used to analyze the conceptualized relationships. The study was conducted with 50 ninth-and-10th-grade Hispanic students in a Colorado high school, over 6 months. The primary finding was that through its direct effect on increasing students’ math ability and its indirect effect on increasing students’ perceived math self-efficacy, the digital intervention improved students’ perceptions of their functionings and future possibilities. What this study specifically underscores is the importance of taking a coherent and purposeful approach toward the design of digital student-directed educational technology, especially for ELL students who may have specific learning needs.     

Reduced order optimization for model predictive control using principal control moves

In order to reduce the computational complexity of model predictive control (MPC) a proper input signal parametrization is proposed in this paper which significantly reduces the number of decision variables. This parametrization can be based on either measured data from closed-loop operation or simulation data. The snapshots of representative time domain data for all manipulated variables are projected on an orthonormal basis by a Karhunen-Loeve transformation. These significant features (termed principal control moves, PCM) can be reduced utilizing an analytic criterion for performance degradation. Furthermore, a stability analysis of the proposed method is given. Considerations on the identification of the PCM are made and another criterion is given for a sufficient selection of PCM. It is shown by an example of an industrial drying process that a strong reduction in the order of the optimization is possible while retaining a high performance level.