A recursive approach to space resection using straight lines

An approach using straight lines as features to solve the photogrammetric space resection problem is presented. An explicit mathematical model relating straight lines, in both object and image space, is used. Based on this model, Kalman Filtering is applied to solve the space resection problem. The recursive property of the filter is used in an iterative process which uses the sequentially estimated camera location parameters to feedback to the feature extraction process in the image. This feedback process leads to a gradual reduction of the image space for feature searching, and consequently eliminates the bottleneck due to the high computational cost of the image segmentation phase. It also enables feature extraction and the determination of feature correspondence in image and object space in an automatic way, i.e., without operator interference. Results obtained from simulated and real data show that highly accurate space resection parameters are obtained as well as a progressive processing time reduction. The obtained accuracy, the automatic correspondence process, and the short related processing time show that the proposed approach can be used in many real-time machine vision systems, making possible the implementation of applications not feasible until now.

Interaction potential between vortex lines for uniaxial superconductors in the London approximation

Two distinct expressions of the interaction potential between arbitrarily oriented curved vortex lines with respect to the crystal c axis are derived within the London approximation. One of these expressions is used to compute the eigenvalues of the elasticity matrix. We examine the elastic properties of the vortex chain lattice, recently proposed, concerning shearing deformation.

Translating conduction-electron spin-resonance lines into lorentzian lines

The Dysonian line in the limit d < or ∼ δ, where d is the thickness and 6 the skin depth, was fitted to a combination of absorption and dispersion Lorentzian lines. This procedure allows one to determine not only microwave conductivity from the Dysonian line but also the true g value, linewidth, and paramagnetic susceptibility by the measurement of five parameters of the ESR absorption-derivative Dysonian line. ©1990 Academic Press, inc.

High resolution spectroscopy of 13CH3OH around the 10R(20) CO2 laser emission: New FIR laser lines, frequency measurement and assignments

We investigated the IR absorption spectrum of 13CH3OH around the frequency of the 10R(20) CO2 laser line. We found two absorption lines which can be excited by 10R(20) and studied the FIR laser emissions excited by this pump line using a waveguide CO2 laser of 300 MHz tunability. We report two new FIR laser lines of large offset, not previously observed due to their weakness and closeness to other stronger lines. We measured the frequencies of five FIR laser lines for the first time by an accurate heterodyne technique and present the complete assignments of the IR-FIR laser systems relative to this pump line. Furthermore we present new frequency values for two FIR laser lines whose frequencies had been previously wrongly measured. Copyright © 1997 Elsevier Science Ltd.

Chromosome damage induced by 5-azacytidine under the influence of caffeine or cytosine arabinoside in CHO-K1 (wild-type) and XRS-5 (mutant) cell lines

5-azacytidine (5-azaC) treatment combined with cytosine arabinoside (ara-C) or caffeine were performed in vitro in Chinese hamster cells, CHO-K1 (wild-type) and xrs-5 (mutant) cell lines, in order to compare the cell response to the induction of chromosomal aberrations. Exponentially growing cells were treated with 5-azaC (4-16 uM) for 1 h, the cells were washed and incubated for 7 h, and 500 uM caffeine or 5 uM ara-C were added to the cultures for the last 2 h. In both cell lines, 5-azaC induced a significantly increase (P<0.01) in the frequencies of aberrations; in the combined treatments (5-azaC + Ara-C), a significant reduction (P<0.05) was observed for the aberrations which were randomly distributed. Caffeine had no influence at the same conditions. 5-azaC induced-DNA lesions were probably processed at S/G2 phase in a common pathway in both cell lines, but alternatively, 5-azaC may cause xrs-5 cells to revert to the wild-type.

Description of the nucleolar activity and karyotype in germinative cell lines of Rhodnius domesticus (Triatominae, Heteroptera)

The purpose of this work was to study the karyotype, spermatogenesis and nucleolar activity at meiosis, in the species Rhodnius domesticus (Heteroptera, Triatominae). The testicular tubules were cytologically prepared by the conventional method of cell crushing and subsequent application of cytogenetic staining techniques with lacto-acetic orcein and silver-ion impregnation. The species under study presented karyotype 2n= 20A+XY, the modal number of the subfamily Triatominae. The chromosomes presented no primary constriction and were therefore characterized as holocentric. It was observed that the sex chromosomes sometimes were located at the periphery, close to the ring formed by autosomes, at first meiotic division. At metaphases II, sex chromosomes were positioned in the center of the autosomal ring, thus evidencing a postreductional behavior. These same chromosomes showed late migration at anaphases and were clearly impregnated with silver-ions, suggesting they bore Nucleolar Organizer Regions. Dispersed nucleolar corpuscles in cytoplasm until telophase II and small dots in spermatids strongly impregnated with silver, could be seen. Thus, it may be inferred that, in triatomines, the nucleolus does not completely disappear but remains in the form of small corpuscles that have a role in cell differentiation.

Eigenvalue analyses of two parallel lines using a single real transformation matrix

For a typical non-symmetrical system with two parallel three phase transmission lines, modal transformation is applied using some examples of single real transformation matrices. These examples are applied searching an adequate single real transformation matrix to two parallel three phase transmission line systems. The analyses are started with the eigenvector and eigenvalue studies, using Clarke's transformation or linear combinations of Clarke's elements. The Z C and parameters are analyzed for the case that presents the smallest errors between the exact eigenvalues and the single real transformation matrix application results. The single real transformation determined for this case is based on Clarke's matrix and its main characteristic is the use of a unique homopolar reference. So, the homopolar mode becomes a connector mode between the two three-phase circuits of the analyzed system. ©2005 IEEE.

Fault identification in distribution lines using intelligent systems and statistical methods

The main objective involved with this paper consists of presenting the results obtained from the application of artificial neural networks and statistical tools in the automatic identification and classification process of faults in electric power distribution systems. The developed techniques to treat the proposed problem have used, in an integrated way, several approaches that can contribute to the successful detection process of faults, aiming that it is carried out in a reliable and safe way. The compilations of the results obtained from practical experiments accomplished in a pilot distribution feeder have demonstrated that the developed techniques provide accurate results, identifying and classifying efficiently the several occurrences of faults observed in the feeder. © 2006 IEEE.

Modal representation of three-phase lines applying two transformation matrices: Evaluation of its eigenvectors

The objective of this paper is to show an alternative representation in time domain of a non-transposed three-phase transmission line decomposed in its exact modes by using two transformation matrices. The first matrix is Clarke's matrix that is real, frequency independent, easily represented in computational transient programs (EMTP) and separates the line into Quasi-modes α, β and zero. After that, Quasi-modes a and zero are decomposed into their exact modes by using a modal transformation matrix whose elements can be synthesized in time domain through standard curve-fitting techniques. The main advantage of this alternative representation is to reduce the processing time because a frequency dependent modal transformation matrix of a three-phase line has nine elements to be represented in time domain while a modal transformation matrix of a two-phase line has only four elements. This paper shows modal decomposition process and eigenvectors of a non-transposed three-phase line with a vertical symmetry plane whose nominal voltage is 440 kV and line length is 500 km. ©2006 IEEE.

Some considerations about a new procedure to derive transmission line parameters concerning three-phase lines

The paper shows an alternative methodology to calculate transmission line parameters per unit length and to apply it in a three-phase line with a vertical symmetry plane. This procedure is derived from a general procedure where the modal transformation matrix of the line is required. In this paper, the unknown modal transformation matrix requested by general procedure is substituted by Clarke's matrix. With the substitution that is shown in the paper, the transmission line parameters can be obtained starting from impedances measured in one terminal of the line. First, the article shows the classical methodology to calculate frequency dependent transmission line parameters by using Carson and Pollaczeck's equations for representing the ground effect and Bessel's functions to represent the skin effect. After that, a new procedure is shown to calculate frequency dependent transmission line parameters directly from currents and voltages of an existing line. Then, this procedure is applied in a non-transposed three-phase transmission line whose parameters have been previously calculated by using the classical methodology. Finally, the results obtained by using the new procedure and by using the classical methodology are compared. The article shows simulation results for typical frequency spectra of switching transients (10 Hz to 10 kHz). Results have shown that procedure has © 2006 IEEE.

Sensitivity analysis for overload-relief in transmission lines using an implicitly coupled method (CRIC)

The restructuring of energy markets to provide free access to the networks and the consequent increase of the number of power transactions has been causing congestions in transmission systems. As consequence, the networks suffer overloads in a more frequent way. One parameter that has strong influence on transfer capability is the reactive power flow. A sensitivity analysis can be used to find the best solution to minimize the reactive power flows and relief, the overload in one transmission line. The proposed methodology consists on the computation of two sensitivities based on the use of the Lc matrix from CRIC (Constant Reactive Implicitly Coupled) power flow method, that provide a set of actions to reduce the reactive power flow and alleviate overloads in the lines: (a) sensitivity between reactive power flow in lines and reactive power injections in the buses, (b) sensitivity between reactive power flow in lines and transformer's taps. © 2006 IEEE.

An alternative procedure to decrease the dimension of the frequency dependent modal transformation matrices: Application in three-phase transmission lines with a vertical symmetry plane

The objective of this paper is to show an alternative representation in time domain of a non-transposed three-phase transmission line decomposed in its exact modes by using two transformation matrices. The first matrix is Clarke's matrix that is real, frequency independent, easily represented in computational transient programs (EMTP) and separates the line into Quasi-modes α, β and zero. After that, Quasi-modes α and zero are decomposed into their exact modes by using a modal transformation matrix whose elements can be synthesized in time domain through standard curve-fitting techniques. The main advantage of this alternative representation is to reduce the processing time because a frequency dependent modal transformation matrix of a three-phase line has nine elements to be represented in time domain while a modal transformation matrix of a two-phase line has only four elements. This paper shows modal decomposition process and eigenvectors of a non-transposed three-phase line with a vertical symmetry plane whose nominal voltage is 440 kV and line length is 500 km. © 2006 IEEE.

DCOOD optically pumped by a13CO2 laser: New terahertz laser lines

In this work, we report new optically pumped terahertz laser lines from DCOOD. An isotopic 13CO2 laser was used for first time as pump source, and a Fabry-Perot open cavity was used as a terahertz laser resonator. Optoacoustic absorption spectra were used as a guide to search for new terahertz laser lines. We could observe six new laser lines in the range from 303.8μm (0.987 THz) to 725.1μm (0.413 THz). The lines were characterized according to wavelength, relative polarization, relative intensity, and optimum working pressure. The transferred Lamb-dip technique was used to measure the frequency absorption transition both for this laser lines. © 2008 American Institute of Physics.

Application of a serum/protein-free medium for the growth of mammalian cell lines and high level production of classical, variant and very virulent strain of infectious bursal disease virus (IBDV)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Using state-space techniques to represent frequency dependent single-phase lines directly in time domain

This paper proposes to use a state-space technique to represent a frequency dependent line for simulating electromagnetic transients directly in time domain. The distributed nature of the line is represented by a multiple 1t section network made up of the lumped parameters and the frequency dependence of the per unit longitudinal parameters is matched by using a rational function. The rational function is represented by its equivalent circuit with passive elements. This passive circuit is then inserted in each 1t circuit of the cascade that represents the line. Because the system is very sparse, it is possible to use a sparsity technique to store only nonzero elements of this matrix for saving space and running time. The model was used to simulate the energization process of a 10 km length single-phase line. ©2008 IEEE.