Computerized Classification Testing and Its Relationship to the Testing Goal

Assessment can serve different goals. If the aim of testing is to classify respondents into one of multiple levels instead of obtaining a precise estimate of the respondent’s ability, computerized classification testing can be used. This type of testing requires algorithms for item selection and making the classification decision. The result of the test administration is provided in a report about the decision with sometimes additional feedback. The design of all these components of the test should be in line with the testing goal. Several goals have been defined for assessment which make a judgment about: pupils, the learning process, groups of students and schools, and the quality of education. The possibilities for use of computerized classification testing for different testing goals are investigated in the current pape

Belbin Revisited: The Construct Validity of the Interplace II Team Role Instrument

In the present study the construct validity of the revised edition of the Belbin Team Roles measure, the so-called Interplace II program, is tested. Three parallel parts were used to determine someone’s team roles. The sample included 1434 persons who were asked to fill out the self-perception inventory and the self-perception assessment, whereas the observer assessment sheet was filled out by at least four observers. The inter-rater reliability appeared to be satisfactory across all team roles. As for the construct validity, which was studied in a multitrait-multimethod design using structural equation modeling, the results revealed that the discriminant and convergent validity for the instrument as a whole is good; only a small effect could be contributed to method variance.Belbin;multitrait-multimethod methodology;team roles;teams

State space description of national economies: the V4 countries

We present a new approach to description of national economies. For this we use the state space viewpoint, which is used mostly in the theory of dynamical systems and in the control theory. Gross domestic product, inflation, and unemployment rates are taken as state variables. We demonstrate that for the considered period of time the phase trajectory of each of the V4 countries (Slovak Republic, Czech Republic, Hungary, and Poland) lies approximately in one plane, so that the economic development of each country can be assocated with a corresponding plane in the state space. The suggested approach opens a way to a new set of economic indicators (for example, normal vectors of national economies, various plane slopes, 2D angles between the planes corresponding to different economies, etc.). The tool used for computations is orthogonal regression (alias orthogonal distance regression, alias total least squares method), and we also give general arguments for using orthogonal regression instead of the classical regression based on the least squares method. A MATLAB routine for fitting 3D data to lines and planes in 3D is provided.Comment: 13 pages, 18 figure

Neurogenic modulation of micturition: the relation between stimulation intensity and the maximum shortening velocity of the guinea pig detrusor muscle

The course of micturition depends on bladder contractility and urethral resistance. The former is determined by geometrical, muscular and neurogenic factors. The muscular aspects of bladder contractility can be characterized by the parameters Pisv, the isovolumetric detrusor pressure, and vmax, the maximum (unloaded) shortening velocity of the detrusor muscle. The neurogenic control system of the urinary tract modulates bladder contractility, which might effectively change the values of Pisv and vmax. These parameters also depend on the instantaneous bladder volume. In previous work the dependence of Pisv on the intensity of stimulation and bladder volume was measured in guinea pig bladders in vivo and in vitro. In the present work vmax was derived in 5 guinea pig bladder in vitro, using electrical stimulation and the stop-flow technique. This technique implies that pressure values measured at a certain shortening velocity of the bladder circumference and in an isovolumetric contraction at the same volume are used to derive vmax mathematically from the Hill equation. vmax was independent of the bladder volume in the range of 0.6 to 6.1 ml., but it was significantly different for the two intensities of stimulation used. Therefore, it is concluded that the maximum shortening velocity of the guinea pig detrusor muscle depends on the intensity of stimulation. During submaximal stimulation the detrusor not only generates lower pressures, it also contracts more slowly. A possible explanation for this phenomenon is that the bladder is not uniformly stimulated. The isovolumetric pressure measured in the stop-flow test was compared with the isovolumetric pressure measured at the same bladder volume some minutes later. It was observed that shortening had a depressant effect of approximately 33% on the isovolumetric pressure. This implies that the clinically employed stop-flow test might underestimate detrusor contraction strength

Optimizing the Post Sandvik Nanoflex material model using inverse optimization and the finite element method

This article describes an inverse optimization method for the Sandvik Nanoflex steel in cold forming\ud processes. The optimization revolves around measured samples and calculations using the Finite Element\ud Method. Sandvik Nanoflex is part of the group of meta-stable stainless steels. These materials are characterized\ud by a good corrosion resistance, high strength, good formability and crack resistance. In addition, Sandvik\ud Nanoflex has a strain-induced transformation and, depending on austenising conditions and chemical composition,\ud a stress-assisted transformation can occur. The martensite phase of this material shows a substantial aging\ud response. The inverse optimization is a sub-category of the optimization techniques. The inverse optimization\ud method uses a top down approach, as the name implies. The starting point is a prototype state where the current\ud state is to converge on. In our experiment the test specimen is used as prototype and a calculation result as\ud current state. The calculation is then adapted so that the result converges towards the test example. An iterative\ud numerical optimization algorithm controls the adaptation. For the inverse optimization method two parameters\ud are defined: shape of the product and martensite profile. These parameters are extracted from both calculation\ud and test specimen, using Fourier analysis and integrals. An optimization parameter is then formulated from\ud the extracted parameters. The method uses this optimization parameter to increase the accuracy of ”The Post”\ud material model for Sandvik Nanoflex. [1] The article will describe a method to optimize material models, using\ud a combination practical experiments, Finite Element Method and parameter extraction

Comparison of immunofluorescence and enzyme-linked immunosorbent assays for the serology of hantavirus infections.

Three enzyme-linked immunosorbent assay (ELISA) systems based upon different principles were developed for the serology of Hantaan virus infections and compared with an indirect immunofluorescence assay (IFA). The indirect IFA was carried out with gamma-irradiated Hantaan virus-infected and uninfected Vero E6 cells fixed with ethanol (-70 degrees C) or acetone (20 degrees C) on drop slides and a FITC-coupled sheep anti-human Ig preparation. Atypical staining in the IFA was avoided by using ethanol (-70 degrees C) instead of acetone (20 degrees C) fixation. In the first ELISA ('cell-assay'), Hantaan virus-infected or uninfected Vero E6 cells were used as antigens, which after gamma-irradiation were seeded into microtiter ELISA strips. Serial dilutions of human sera were incubated and specific antibodies were demonstrated with a horseradish peroxidase (HRPO)-conjugated sheep anti-human Ig preparation. In the second ELISA ('competition-assay') an affinity-purified human Ig preparation was used as a capture antibody for Hantaan virus antigen. After incubation of serial dilutions of human sera with this coat, the reactivity of the affinity purified anti-Hantaan virus Ig coupled to HRPO was determined. In the third ELISA ('complex trapping blocking [CTB]-assay') the same capture antibody was used to react with a mixture of the antigen and serial dilutions of human sera. The reactivity with the same HRPO conjugate was then determined. The results obtained in the respective assay systems with sera from people at risk or suspected of Hantaan virus infection coincided well. The CTB-ELISA proved to be faster and more sensitive than both the other ELISA systems, without giving more non-specific reactions: it detected almost all the IFA positive samples.(ABSTRACT TRUNCATED AT 250 WORDS