Real-μ bounds based on fixed shapes in the Nyquist plane: Parabolas, hyperbolas, cissoids, nephroids, and octomorphs

In this paper we introduce new bounds for the real structured singular value. The approach is based on absolute stability criteria with plant-dependent multipliers that exclude the Nyquist plot from fixed plane curve shapes containing the critical point − + _jO. Unlike half-plane and circle-based bounds the critical feature of the fixed curve bounds is their ability to differentiate between the real and imaginary components of the uncertainty. Since the plant-dependent multipliers have the same functional form at all frequencies, the resulting graphical interpretation of the absolute stability criteria are frequency independent in contrast to the frequency-dependent off-axis circles that arise in standard real-μ bounds.     

The μ-basis of a planar rational curve—properties and computation

A moving line L(x,y;t)=0 is a family of lines with one parameter t in a plane. A moving line L(x,y;t)=0 is said to follow a rational curve P(t) if the point P(t₀) is on the line L(x,y;t₀)=0 for any parameter value t₀. A μ-basis of a rational curve P(t) is a pair of lowest degree moving lines that constitute a basis of the module formed by all the moving lines following P(t), which is the syzygy module of P(t). The study of moving lines, especially the μ-basis, has recently led to an efficient method, called the moving line method, for computing the implicit equation of a rational curve [3 and 6]. In this paper, we present properties and equivalent definitions of a μ-basis of a planar rational curve. Several of these properties and definitions are new, and they help to clarify an earlier definition of the μ-basis [3]. Furthermore, based on some of these newly established properties, an efficient algorithm is presented to compute a μ-basis of a planar rational curve. This algorithm applies vector elimination to the moving line module of P(t), and has O(n²) time complexity, where n is the degree of P(t). We show that the new algorithm is more efficient than the fastest previous algorithm [7].     

K competing queues with geometric service requirements and linear costs: The μc-rule is always optimal

In this note, a discrete-time system of K competing queues with geometric service requirements and arbitrary arrival patterns is studied. When the cost per slot is linear in the queue sizes, it is shown that the μc-rule minimizes the expected discounted cost over the infinite horizon.     

μ-Bases and singularities of rational planar curves

We provide a technique to detect the singularities of rational planar curves and to compute the correct order of each singularity including the infinitely near singularities without resorting to blow ups. Our approach employs the given parametrization of the curve and uses a μ-basis for the parametrization to construct two planar algebraic curves whose intersection points correspond to the parameters of the singularities including infinitely near singularities with proper multiplicity. This approach extends Abhyankar's method of t-resultants from planar polynomial curves to rational planar curves. We also derive the classical result that for a rational planar curve of degree n the sum of all the singularities with proper multiplicity is (n−1)(n−2)/2. Examples are provided to flesh out our results.     

Effect of the reaction time, reagent concentration and sample thickness on the thermal derivatisation of p porous silicon with α-undecene and ω-carboxy alkenes: A FTIR investigation

This paper presents a detailed study, based on Fourier transform infrared (FTIR) analysis, on the derivatisation of p⁺-type porous silicon (PS) via thermal activated hydrosilylation of α-undecene. The α-undecene was used as a model for alkene precursor to calculate the efficiency of the hydrosilylation reaction, determined by comparing the integrated intensity of the SiH_x peaks (2200–2000 cm⁻¹) of the as-prepared and modified sample, by varying three parameters: the reaction time, the reagent concentration and the sample thickness. This study aims to optimize the PS derivatisation as a function of the thickness, in order to consider the thermal activation as a useful process for modifying PS slab waveguide for sensing application. Moreover two methods using ω-carboxy alkenes (where the carboxylic moiety was an ester or an acid) to obtain a PS surface –COOH-terminated, to be exploited for bioconjugation protocols, were tested and the reactions efficiency compared with the alkene model, i.e. α-undecene. FTIR spectroscopy and contact angle measurements were used to characterize the modified PS samples.     

Creating change and driving innovation in highly automated and lean organizations: The Temporal Think Tank™ (T3™)

This paper introduces the concept of the temporal think tank™ (T3™), a temporary in-house research center, based on case studies with a highly automated global manufacturer and in various small-sized manufacture (SME's). The T3™ brings individuals from across the organization together in a team setting in which they are charged to look at the future, develop their decision-making skills, and use entrepreneurial thinking to incubate new processes and/or products. After an appropriate time in the temporal think tank™, the individuals are asked to return to their regular positions to implement the best practices and best ideas and doing so spur the organization forward. At intervals, the temporal think tanks™ can be reconvened, or reconstituted with new participants. This approach prepares technology champions for the SME, who can return to the organization with a fresh outlook and renewed energy to keep the enterprise at the peak of efficiency and effectiveness.     

Mineral potential targeting and resource assessment based on 3D geological modeling in Luanchuan region, China

In this paper, we used 3D modeling and nonlinear methods (fractal, multifractal, and probabilistic neural networks (PNN)) for regional mineral potential mapping and quantitative assessment for porphyry and skarn-type Mo deposits and hydrothermal vein-type Pb-Zn-Ag deposits in the Luanchuan region, China. A 3D geological model was constructed from various geological maps, cross sections, boreholes, and gravity and magnetic data. Geological features associated with mineralization were extracted using the 3D geological model and metallogenic models of porphyry and skarn-type Mo and Pb-Zn-Ag deposits. The multifractal method, principal component analysis, and power spectrum-area method were used to separate regional variability from local variability in the geochemical data. A 2.5D forward modeling of gravity and magnetic data was carried out to define the geometry, depth, and physical properties of geological bodies at depth. 3D visualization of the results assisted in understanding the spatial relations between the deposits and the other geological bodies (e.g., igneous intrusions). The PNN method was applied to represent and integrate multiple anomalies for mineral potential modeling. The concentration-area fractal method was used to classify the PNN mineral potential model. Three levels (ground surface and two subsurface horizontal planes) of mineral potential models were evaluated for undiscovered Mo and Pb-Zn-Ag deposits. Validation of the results shows that 3D modeling was useful for not only accurately extracting geological features but also for predicting potential mineral targets and evaluating mineral resources. The mineral potential targets identified consist of eight Mo potential targets and 15 Pb-Zn-Ag potential targets. Based on grade-tonnage data from the known Mo and Pb-Zn-Ag deposits and the results of 3D modeling, estimated potential resources of each of these types of deposits are 10.8 and 153.1 Mt (Pb+Zn is 152.9 Mt and Ag is 0.92 Mt), respectively.     

Characterization of ozone sensors based on WO3 reactively sputtered films: influence of O2 concentration in the sputtering gas, and working temperature

We report on electrical responses of tungsten oxide thin film ozone sensors based on a tungsten trioxide (WO₃)/tin oxide (SiO₂)/Si structure with interdigitated Pt electrodes. The influence of O₂ concentration in the sputtering gas and working temperature of the sensor are investigated. Sensitivity to ozone increases with O₂ content in the sputtering gas. It reaches its highest value for sensors fabricated with 50% O₂. For these sensors, the best ozone sensitivity and shortest response and recovery times are obtained at a working temperature of 523 K. Ozone sensitivity is compared to other ozone sensors.     

Remarks regarding the gap between continuous, Lipschitz, and differentiable storage functions for dissipation inequalities appearing in H∞ control

This paper deals with the regularity of solutions of the Hamilton–Jacobi inequality which arises in H_∞ control. It shows by explicit counterexamples that there are gaps between existence of continuous and locally Lipschitz (positive definite and proper) solutions, and between Lipschitz and continuously differentiable ones. On the other hand, it is shown that it is always possible to smooth-out solutions, provided that an infinitesimal increase in gain is allowed.     

Applying the Practical Inquiry Model to investigate the quality of students’ online discourse in an information ethics course based on Bloom’s teaching goal and Bird’s 3C model

The goal of this study is to better understand how the study participants’ cognitive discourse is displayed in their learning transaction in an asynchronous, text-based conferencing environment based on Garrison’s Practical Inquiry Model (2001). The authors designed an online information ethics course based on Bloom’s taxonomy of educational objectives and Bird’s 3C model (Content–Construction–Consolidation). The content analyzed included the participants’ message posts, the quality of the dialogue and the scaffolding strategies for mentoring used by group leaders and teachers.     

Cultural Cues in Students' Computer‐Mediated Communication: Influences on E‐mail Style,Perception of the Sender,and Willingness to Help

Computer‐mediated communication among university students with different cultural backgrounds has become widespread. In this study, we examine how undergraduates (N = 130) react to cultural cues when responding to an e‐mail request for cooperation sent by a peer. Participants rated the sender's personality and stated their willingness to help. In the inquiry, 2 types of cultural cues were varied, resulting in a 2 × 2 factorial design: ethnicity (German vs. Chinese name) and communication style (Western vs. Asian). Results showed that participants aligned their responses to the communication style; however, the ethnicity cue influenced the wording of their response, their perception of the sender's personality and their willingness to help. Results are discussed regarding communication accommodation and social judgment theories.     

Steps, techniques, and technologies for the development of intelligent applications based on Semantic Web Services: A case study in e-learning systems

Semantic Web Services domain has gained special attention in academia and industry. It has been adopted as a promise to enable automation of all aspects of Web Services provision and uses, such as service creation, selection, discovery, composition, and invocation. However, the development of intelligent systems based on Semantic Web Services (SWS) is still a complex and time-consuming task, mainly with respect to the choice and integration of technologies. In this paper, we discuss some empirical issues associated with the development process for such systems and propose a systematic way for building intelligent applications based on SWS by providing the development process with steps, techniques and technologies. In addition, one experiment concerning the implementation of a real e-learning system using the proposed approach is described. The evaluation results from this experiment showed that our approach has been effective and relevant in terms of improvements in the development process of intelligent applications based on SWS.