Jensen's Method Research Articles

A Research on Information Disclosure Quality and Stock Price Volatility in Capital Market of Iran

The current research studies the relationship between disclosure quality and the stock price in the Tehran stock exchange. In this research, the disclosure quality has been calculated using Jensen's method. Also, a survey was carried out in 29 companies, from the list of accepted companies at the Tehran stock exchange, which offered the information for a 5-year period from 2005 to the end of 2010. The main hypothesis of this research is that there is a significant relationship between the disclosure quality and stock price in the Tehran stock exchange, and regression has been used for testing this hypothesis. After general and annual testing of the data, the test error was more than 5%, which means that the test was not significant at any level; so, we can say with confidence that no significant relationship between the variables was found.

Calibration and Validation of a Mean Value Model for Turbocharged Diesel Engine

In order to meet the high requirements of the control strategies for an effective and accuracy control-oriented model, a mean value model for a turbocharged diesel engine has been developed on the Matlab/Simulink. And then the error sources leading to the simulation inaccuracy have been analyzed comprehensively and two sets of experiments for model calibration and validation have been designed. Then a model calibration process and a model validation process have been proposed, with which the developed model is well calibrated and validated against the two sets of experimental data. Especially, for the compressor model calibration, an improved Jensen and Kristense method has been introduced to interpolate and extend the compressor maps. And turbine efficiency observer is designed for the rectification of turbine maps. At last, the calibration and validation process and improved methods and observer for turbocharger are verified and evaluated.

Relay Precoding for Non-Regenerative MIMO Relay Systems with Partial CSI Feedback

We consider a relay precoding problem in a non-regenerative multiple-input multiple-output (MIMO) relay system, where the relay has the perfect channel state information of the source-relay link and only the covariance information of the relay-destination link. The average capacity seen by the relay is maximized under a relay transmit power constraint. The relay precoding problem is transformed to its equivalent power allocation problem at the relay. The optimal power allocation solution is then derived by formulating the optimization problem via difference of convex (DC) functions programming. To reduce the computational complexity, we also propose a suboptimal scheme by modifying the naive Jensen method. Furthermore, we propose the maximum eigenmode relaying (MER) scheme, which allocates the relay transmit power only to the maximum eigenmode. A necessary and sufficient condition for the MER to be asymptotically optimal is derived in the high signal-to-noise ratio (SNR) regime of the source-relay link. The performance of the proposed schemes is investigated through extensive numerical simulations.

A study of tubercular lymphadenitis: A comparison of various laboratory diagnostic modalities with a special reference to tubercular polymerase chain reaction

Objective: The purpose of our study was to compare various laboratory diagnostic methods, namely histopathological examination, Ziehl-Neelsen (ZN) stain, AFB culture by conventional Lowenstein–Jensen (LJ) method and fluorescence-based mycobacterial growth indicator tube (MGIT) technique and polymerase chain reaction (PCR) in clinically suspected cases of tubercular lymphadenitis. Materials and Methods: A total of 65 lymph nodes biopsied from patients clinically suspected of having tubercular lymph nodes were included. Specimens were processed for AFB culture after NaOH-NALC concentration and inoculation on LJ medium and using the MGIT system. PCR was performed on all specimens using a commercial nested PCR kit targeting IS6110 insertion element of Mycobacterium tuberculosis complex. All lymph node specimens were subjected to histopathological examination. Results: Of the 65 lymph nodes, 37 (56.9%) were positive on MGIT culture and 45 (69.2%) were positive by PCR. Histopathology showed maximum sensitivity (96%) but with compromised specificity (78.5%). PCR showed 90.1% sensitivity and 100% specificity. The mean turnaround time for mycobacterial growth in smear negative specimens was 30 days determined by LJ and 20 days by MGIT techniques. Conclusion: PCR is a rapid and useful method for diagnosis of TB lymphadenitis and definitely increases the positive predictive value of a positive histopathology report. MGIT is better than LJ culture as regards time to positivity and higher yield.

Spectrofluorometric analysis of cardiotonic steroids.

Abstract The sensitive and specific fluorimetric methods introduced by Jensen (1952; 1953) for digitalis estimation were re-evaluated for the assay of cardiotonic steroids and other steroids of biological interest. Characteristics of the excitation and fluorescence spectra were determined. Using a modification of Jensen's original digitoxin method and a spectrofluorometer, a linear relation was demonstrated between fluorescence intensity and concentrations from 0.01 to 6 μg./ml. for both digitoxin and digoxin. Application of these methods to the assay of gitoxin and cholesterol would seem to be equally practicable. In addition, scillaren A and B and strophanthin K can be made to fluoresce weakly. On the other hand, ouabain, cholestanol, testosterone, and hydrocortisone showed no fluorescence. Possible mechanisms of the reactions are discussed

Comparative experimental study on absolute measurement of spherical surface with two-sphere method

Abstract The two-sphere method with multiple confocal measurements and a “cat's-eye” measurement is used widely in high accuracy interferometry, which can obtain the absolute surface data of the tested spherical surface. We provide a comparative experimental study on absolute testing procedures for spherical surface with two-sphere method, which include the classical Jensen method with three position measurements, the Zygo method with five position measurements and a variant of the Jensen method. The variant of the Jensen method can combine the multiple “three-position” measurements based on the fiducial method and averaging method. The repeatability of the involved absolute measurement methods is also studied by the five set experiments, and the corresponding Zernike fitting coefficients are compared in detail. The experimental results are meaningful for implementation of two-sphere method with higher repeatability in practice.

Standardization of first and second-line antitubercular susceptibility testing using BacT Alert 3D system: a report from a tertiary care centre in India

Resurgence of multidrug resistant tuberculosis has lead to demand for rapid susceptibility testing. Conventional methods take > 3 weeks and are tedious. Automated methods have superseded them for first line drug susceptibility testing. An attempt was made to standardize first and second line susceptibility testing using the BacT Alert 3D system (Biomerieux). And compare results with Lowenstein Jensen's (LJ) method. 121 isolates of Mycobacterium tuberculosis, 67 pulmonary and 54 extra pulmonary were subjected to sensitivity to first and second line drugs. Multidrug resistance was detected equally by both methods at 15.7%. 100% agreement was observed between the two methods for aminoglycosides, rifampicin, ethionamide and ciprofloxacin. 91.5% agreement was observed for isoniazid, 85% for pyrazinamide and 72.4% for ethambutol. The time taken by LJ method was 18-32 days and BacT Alert 3D system took 4-12 days. In the lesser developed nations where tuberculosis is rampant a rapid effective method for confirming multidrug resistant tuberculosis is definitely desirable and the BacT Alert 3D system was found an effective method when compared to the 'gold standard' LJ proportion.

Synchronous culture of Plasmodium falciparum at high parasitemia levels

This protocol describes a method for preparing cultures of Plasmodium falciparum synchronized at any intraerythrocytic stage. Using this method, around 60% parasitized cells may be obtained. On the basis of Trager and Jensen's original continuous culture method, our approach relies on the use of fresh human blood not older than 2 weeks, a low hematocrit between 0.8 and 1.5%, a starting frozen inoculum of 10% ring-stage parasitemia, human serum replaced with AlbuMAX I and alternating sorbitol and Percoll synchronization methods to shorten the cycle window to 4-6 h and reduce sorbitol toxicity. From our synchronized high parasite density cultures, 3-5 ml of infected red blood cells can be obtained in 1 week, corresponding to 1.2 mg of total parasite protein per ml of harvested culture. On the basis of the variables parasitemia and packed cell volume, we provide an equation to accurately calculate the amount of complete medium required every 24 h corrected for the cycle stage and capacity of the culture flask. Ten days suffice to complete the protocol from a frozen stock of parasites.

Modelization of acoustic waves radiation from sources of complex geometry aperture

The Rayleigh integral giving the impulse response for the acoustic velocity potential cannot always be determined analytically for all types of transducer apertures. The shape of the transducer surface and the spatial distribution of the excitation on its surface can complicate the calculation. This makes using numeric methods indispensable. One of these methods consists in discritizing the aperture surface in polygonal shape elements. Our work makes use of both methods of Jensen and Faure [IEEE UFFC 39-2(1992)262, Acta Acustica 2(1994)257]. In the former, the transducer surface is subdivided in triangles. The latter one uses additional virtual triangles one side of which is that of the physical element and its summit is the field point projection on the plane containing the considered physical element. Additionally, a rotation of the virtual triangle around the field point projection is performed. In this work, the orientations of those virtual triangles are considered according to Jensen method and their contributions to the impulse response are calculated according to the two situations described by Faure. The combination of the two methods is, then, generalized to the case of nonplanar complex surfaces such as concave phased arrays.

Comparison of Evapotranspirations Measured by Lysimeter and Calculated by Various Estimating Methods

The accuracy of methods for estimating evapotranspiration at upland in a humid area was investigated at a soybean field. First, hourly evapotranspiration were estimated using the Bowen ratio method, Brown‐Rosenberg method, Batholic method and Monteith method. Second, daily evapotranspiration were estimated using the Ostromeki method, Makkink method, Stephens method, Turc method, Jensen method, van Bavel method, van Bavel‐Businger method and Penman method. Correlativity between estimated and observed values was compared, and superiority of these methods was discussed. When hourly meteorological data were available, the Batholic method was accurate next to the Bowen ratio method. And when daily meteorological data were available, the Stephens method showed high accuracy next to the Penman method, though this method only use average daily temperature and daily solar radiation.

Duncan's Spearman's G — Does It have a Clinical Application?

When IQ tests are ranked by the magnitude of their score gains over time, this hierarchy lacks a positive correlation with the same tests ranked by their g loadings. Therefore, Jensen declared IQ gains “hollow” and, by implication, extended this judgment to score gains that indicated that blacks had made IQ gains on whites. We offer four exploratory meta-analyses that apply Jensen's method to the subtest score differences between normal subjects and those suffering from certain afflictions: iodine deficiency (K = 6, N = 196), prenatal cocaine exposure (K = 2, N = 215), fetal alcohol syndrome and degree of fetal alcohol syndrome (respectively, K = 1, N = 110; and K = 3, N = 125), and traumatic brain injury (K = 14, N = 629). All of these create a substantial cognitive deficit in those afflicted. However, the correlations between subtest score differences and g loadings run from − 0.23 to + 0.12, with an unweighted average of 0.00.

Two failures of Spearman's hypothesis: The GATB in Holland and the JAT in South Africa

Spearman's hypothesis states that the differences between Blacks and Whites in psychometric IQ are attributable to a fundamental difference in general intelligence ( g). To investigate this hypothesis, Jensen devised the method of correlated vectors. This method involves calculating the correlation between the factor loadings of the subtest and the observed differences in means. Although the hypothesis concerns U.S. populations, Jensen's test has also been used to investigate other groups. The aim of the present paper is to test Spearman's hypothesis in a published Dutch and a published South African data set. Both data sets were previously analyzed by Jensen's method, and the results were interpreted in support of Spearman's hypothesis. In this paper, we reanalyzed both data sets by Multigroup Confirmatory Factor Analysis (MGCFA). We find that the hypothesis of factorial invariance, which implies that the same construct is measured in the groups, must be rejected. This greatly complicates any comparison of the group with respect to the test scores and makes it impossible to determine the role, if any, of g in explaining the observed differences in psychometric IQ. This conclusion runs counter to the conclusion that Spearman's hypothesis is supported in these data sets.

Investigating Group Differences on Cognitive Tests Using Spearman's Hypothesis: An Evaluation of Jensen's Method

Jensen has posited a research method to investigate group differences in cognitive tests. This method consists of first extracting a general intelligence factor by means of exploratory factor analysis. Secondly, similarity of factor loadings across groups is evaluated in an attempt to ensure that the same constructs are measured. Finally, the correlation is computed between the loadings of the tests on the general intelligence factor and the mean differences between groups on the tests. This part is referred to as a test of "Spearman's Hypothesis", which essentially states that differences in g account for the main part of differences in observed scores. Based on the correlation, inferences are made with respect to group differences in general intelligence. The validity of these inferences is investigated and compared to the validity of inferences based on multi-group confirmatory factor analysis. For this comparison, population covariance matrices are constructed which incorporate violations of the central assumption underlying Jensen's method concerning the existence of g and/or violations of Spearman's Hypothesis. It is demonstrated that Jensen's method is quite insensitive to the violations. This lack of specificity is observed consistently for all types of violations introduced in the present study. Multi-group confirmatory factor analysis emerges as clearly superior to Jensen's method.

Improving the Gumbel analysis by using M-th highest extremes

Improvements to the Gumbel method of extreme value analysis of wind data made over the last two decades are reviewed and illustrated using sample data for Jersey. A new procedure for extending the Gumbel method to include M-th highest annual extremes is shown to be less effective than the standard method, but leads to a method for calibrating peak-over-threshold methods against the standard Gumbel approach. Peak-over-threshold methods that include at least the 3rd highest annual extremes, specifically the modified Jensen and Franck method and the Method of independent storms are shown to give the best estimates of extremes from observations.

The “Jensen Effect” and the “Spearman-Jensen hypothesis” of Black-White IQ differences

Arthur Jensen's research on the biological basis of mental ability has culminated in his encyclopedic new work The g Factor (1998) which massively confirms “Spearman's (1927) hypothesis” that Black-White IQ differences vary systematically as a function of each test's g loading. More generally. The g Factor consolidates the psychometric, neurophysiological, behavior genetic, and comparative evidence for the existence and importance of g, and links it to evolutionary processes. But perhaps Jensen's greatest legacy to science will be his pioneering method of correlated vectors which subsumes, under a much broader principle, his famous (1969a) hypothesis about the heritability of the Black-White IQ gap and, as Osborne (1980) dubbed it, the “Spearman-Jensen hypothesis” that Black-White IQ differences are greatest on the g-factor. Jensen's method of correlated vectors demonstrates that g (specifically a test's g loading) is the best predictor of that test's correlation with a given variable. In future, when a significant correlation occurs between g-factor loadings and variable X, the result might usefully be called a “Jensen Effect” (for that X variable), because otherwise there is no name for it, only a long explanation of how the effect was achieved. Naming it the “Jensen Effect” would honor one of the greatest psychologists of our time.

Electrophoretic variations of enzyme, GDH (NADP-dependent glutamate dehydrogenase)(EC. 1.4.1.4) in characterizing clones and isolates of Malaysian Plasmodium falciparum.

Malaysian, African and Thai Plasmodium falciparum isolates were cultured in vitro by the Trager and Jensen method (1976; 1977) and were later cloned by the limiting dilution method (Rosario, 1981). Forty-eight clones were obtained and were characterized by electrophoretic variations of GDH (NADP-dependent glutamate dehydrogenase)(EC. 1.4.1.4). It was found that they were pure clones because they possessed either GDH-1 or GDH-2 unlike their parent isolates which exhibited both GDH-1 and GDH-2.

A combinatorial forcing for coding the universe by a real when there are no sharps

AbstractAssuming 0# does not exist, we present a combinatorial approach to Jensen's method of coding by a real. The forcing uses combinatorial consequences of fine structure (including the Covering Lemma, in various guises), but makes no direct appeal to fine structure itself.

Numerical methods for reliability evaluation of Markov closed fault-tolerant systems

This paper compares three numerical methods for reliability calculation of Markov, closed, fault-tolerant systems which give rise to continuous-time, time-homogeneous, finite-state, acyclic Markov chains. The authors consider a modified version of Jensen's method (a probabilistic method, also known as uniformization or randomization), a new version of ACE (acyclic Markov chain evaluator) algorithm with several enhancements, and a third-order implicit Runge-Kutta method (an ordinary-differential-equation solution method). Modifications to Jensen's method include incorporating stable calculation of Poisson probabilities and steady-state detection of the underlying discrete-time Markov chain. The new version of Jensen's method is not only more efficient but yields more accurate results. Modifications to ACE algorithm are proposed which incorporate scaling and other refinements to make it more stable and accurate. However, the new version no longer yields solution symbolic with respect to time variable. Implicit Runge-Kutta method can exploit the acyclic structure of the Markov chain and therefore becomes more efficient. All three methods are implemented. Several reliability models are numerically solved using these methods and the results are compared on the basis of accuracy and computation cost.

Stiffness-tolerant methods for transient analysis of stiff Markov chains

Three methods for numerical transient analysis of Markov chains, the modified Jensen's method (Jensen's method with steady-state detection of the underlying DTMC and computation of Poisson probabilities using the method of Fox and Glynn [1]), a third-order L-stable implicit Runge-Kutta method, and a second-order L-stable method, TR-BDF2, are compared. These methods are evaluated on the basis of their performance (accuracy of the solution and computational cost) on stiff Markov chains. Steady-state detection in Jensen's method results in large savings of computation time for Markov chains when mission time extends beyond the steady-state point. For stiff models, computation of Poisson probabilities using traditional methods runs into underflow problems. Fox and Glynn's method for computing Poisson probabilities avoids underflow problems for all practical problems and yields highly accurate solutions. We conclude that for mildly stiff Markov chains, the modified Jensen's method is the method of choice. For stiff Markov chains, we recommend the use of the L-stable ODE methods. If low accuracy (upto eight decimal places) is acceptable, then TR-BDF2 method should be used. If higher accuracy is desired, then we recommend third-order implicit Runge-Kutta method.

Mixed-Weibull parameter estimation for burn-in data using the Bayesian approach

A Bayesian approach is presented for both grouped and ungrouped burn-in test data, to come up with the posterior parameters of the bimodal mixed-Weibull distribution. The concepts of belonging probabilities and fractional ranks are introduced for this approach. A numerical comparison is made by conducting the Kolmogorov-Smirnov goodness-of-fit test on the parameter estimates obtained by Jensen's graphical method, by the Bayesian approach using the conventional separation plotting method and by the Bayesian approach using the fractional rank plotting method. It turns out that the Bayesian approach with the fractional rank plotting method yields the best results.