Education-driven research in CAD

We argue for a new research category, named education-driven research (EDR), which fills the gap between traditional field-specific research that is not concerned with educational objectives and research in education that focuses on fundamental teaching and learning principles and possibly on their customization to broad areas (such as mathematics or physics), but not to specific disciplines (such as CAD). The objective of EDR is to simplify the formulation of the underlying theoretical foundations and of specific tools and solutions in a specialized domain, so as to make them easy to understand and internalize. As such, EDR is a difficult and genuine research activity, which requires a deep understanding of the specific field and can rarely be carried out by generalists with primary expertise in broad education principles. We illustrate the concept of EDR with three examples in CAD: (1) the Split and Tweak subdivisions of a polygon and its use for generating curves, surfaces, and animations; (2) the construction of a topological partition of a plane induced by an arbitrary arrangement of edges; and (3) a romantic definition of the minimal and Hausdorff distances. These examples demonstrate the value of using analogies, of introducing evocative terminology, and of synthesizing the simplest fundamental building blocks. The intuitive understanding provided by EDR enables the students (and even the instructor) to better appreciate the limitations of a particular solution and to explore alternatives. In particular, in these examples, EDR has allowed the author to: (1) reduce the cost of evaluating a cubic B-spline curve; (2) develop a new subdivision curve that is better approximated by its control polygon than either a cubic B-spline or an interpolating 4-point subdivision curve; (3) discover how a circuit inclusion tree may be used for identifying the faces in an arrangement; and (4) rectify a common misconception about the computation of the Hausdorff error between triangle meshes. We invite the scientific community to encourage the development of EDR by publishing its results as genuine research contributions in peer-reviewed professional journals.     

Estimation for the number of components in a mixture model using stepwise split-and-merge EM algorithm

The main difficulty with EM algorithm for mixture model concerns the number of components, say g. This is the question of model selection, and the EM algorithm itself could not estimate g. On the contrary, the algorithm requires g to be specified before the remaining parameters can be estimated. To solve this problem, a new algorithm, which is called stepwise split-and-merge EM (SSMEM) algorithm, is proposed. The SSMEM algorithm alternately splits and merges components, estimating g and other parameters of components simultaneously. Also, two novel criteria are introduced to efficiently select the components for split or merge. Experimental results on simulated and real data demonstrate the effectivity of the proposed algorithm.     

Evaluation of passive microwave snow water equivalent algorithms in the depth hoar-dominated snowpack of the Kuparuk River Watershed, Alaska, USA

This research investigates the utility of passive microwave remote sensing instruments to accurately determine snow water equivalent (SWE) over large spatial extents. Three existing Special Sensor Microwave Imager (SSM/I) snow water equivalent algorithms produced by Chang, Tait and Goodison were evaluated for their ability to determine snow water equivalent in a snowpack containing substantial depth hoar, large faceted snow crystals. The Kuparuk River Watershed (8140 km²) test site on the North Slope of Alaska was chosen for its snowpack containing a think depth hoar layer and long history of ground truth data. A new regional snow water equivalent algorithm was developed to determine if it could produce better results than the existing algorithms in an area known to contain significant depth hoar. The four algorithms were tested to see how well they could determine snow water equivalent: (1) on a per pixel basis, (2) across swath-averaged spatial bands of approximately 850 km², and (3) on a watershed scale. The algorithms were evaluated to see if they captured the annual spatial distribution in snow water equivalent over the watershed. Results show that the algorithms developed by Chang and from this research are generally within 3 cm of the spatially averaged snow water equivalents over the entire watershed. The algorithms produced by Chang, Tait, and in this research were able to predict the basin-wide ground measured snow water equivalent value within a percent error range from −32.4% to 24.4% in the years with a typical snowpack. None of the algorithms produce accurate results on a pixel-by-pixel scale, with errors ranging from −26% to 308%.     

关于从旋涡炉渣回收铜的研究

介绍了用自然澄清法降低、回收旋涡炉渣中的铜的方法。该方法工艺简单。操作方便，不仅降低冶炼成本，同时提高了经济效益。     

2003 Gold Medal Award for Life Achievement in the Science of Psychology.

Presents the 2003 American Psychological Foundation's Gold Medal Award for Life Achievement in the Science of Psychology, which was presented to Robert Rosenthal. A biography of Rosenthal is provided, along with a selected bibliography and the text of the award citation: "For outstanding scientific contributions that have had a profound influence on research methods, empirical investigations, theory, and applications. Robert Rosenthal's seminal research on interpersonal expectancy inspired hundreds of studies with applications within and beyond psychology. His amplification of experimenter- and subject-related artifacts and his insights about ethical issues have improved the way that research is conducted. His statistical contributions are classic and wide ranging, including his body of work on meta-analysis and contrast analysis and his formulation of valuable procedures, such as the binomial effect-size display and counternull statistics. An exceptional scientist, teacher, mentor, and author, Rosenthal, with his generous and brilliant touch, has shaped the lives and work of countless others." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Boiling: Size Distribution of Bubbles as Demanded by the Principle of Maximum Information

The principle of maximum informational entropy is used to find the probability density function for the departure radius of a bubble in boiling on a solid surface. A general relation is derived, which leads to particular expressions.     

Filtration of Non-Newtonian Hydrocarbon Fluid in a High-Frequency Electromagnetic Field

The paper gives the results of experimental investigations of the initial pressure gradient of bituminous oil and the time dependences of variation of the temperature in a formation model and of the well production rate in a microwave-frequency electromagnetic field. The effect of strong decay of the non-Newtonian properties of bituminous oil is revealed. The nonuniformity of temperature distribution over the formation thickness is demonstrated, which depends on the initial production rate of the well and on the duration of stimulation of the bottom-hole zone of formation.     

A Mixed-Approach Analysis of Deformations in Pipe Bends. Part 3. Calculation of Bend Axis Displacements by the Method of Initial Parameters

A problem of deformation of a curved shell loaded by internal pressure, axial force, and temperature difference is discussed. Physical equations are derived whereby the displacements and angles of rotation of the line of centers of mass of cross sections of a shell are related to loading parameters. A general constitutive set of equations for a curved element during its deformation is given. Using a method of initial parameters, an analytical solution is obtained for the differential equations for displacements and angles of rotation of the center line allowing for the action of distributed forces and moments.     

A simple approximation algorithm for the weighted matching problem

We present a linear time approximation algorithm with a performance ratio of 1/2 for finding a maximum weight matching in an arbitrary graph. Such a result is already known and is due to Preis [STACS'99, Lecture Notes in Comput. Sci., Vol. 1563, 1999, pp. 259-269]. Our algorithm uses a new approach which is much simpler than the one given by Preis and needs no amortized analysis for its running time.     

Treatment of low turbidity water by sweep coagulation using bentonite

A novel strategy of sweep coagulation to treat low turbidity water is presented herein. Study findings demonstrated that an Na⁺‐saturated bentonite with medium cation exchange capacity (CEC) resulted in significant turbidity removal at a bentonite dosage of 30 mg dm^?3. Bentonite dispersion with fully delaminated platelets tended to undergo a more porous type of coagulation with intense face‐to‐face interactions of platelets and effectively entrapped TiO₂ particles in band‐type structures. This type of coagulation usually results in a large volume of settled flocs with a fluffy structure and excellent turbidity removal efficiency for sweep coagulation. The sign and magnitude of electrical charge on TiO₂ particles has a minor effect on the efficiency of sweep coagulation. Copyright © 2005 Society of Chemical Industry