Polynomial methods for structure from motion

The authors analyze the limitations of structure from motion (SFM) methods presented in the literature and propose the use of a polynomial system of equations, with the unit quaternions representing rotation, to recover SFM under perspective projection. The authors combine the equations by the method of resultants with the MAXIMA symbolic algebra system, reducing the system to a single polynomial. Its real roots are then found with Sturm sequences. Since this system has multiple solutions, a hypothesize-and-verify scheme is used to eliminate incorrect ones. The scheme diminishes the sensitivity of using polynomial equations. The authors examine the effect of different rotation axes and angles on SFM accuracy and compare the performance of the algorithm to a few earlier approaches. Generally, it is found that a large amount of motion is the most important factor in getting good SFM accuracy     

Hyperplasia of lymphatic vessels in VEGF-C transgenic mice

No growth factors specific for the lymphatic vascular system have yet been described. Vascular endothelial growth factor (VEGF) regulates vascular permeability and angiogenesis, but does not promote lymphangiogenesis. Overexpression of VEGF-C, a ligand of the VEGF receptors VEGFR-3 and VEGFR-2, in the skin of transgenic mice resulted in lymphatic, but not vascular, endothelial proliferation and vessel enlargement. Thus, VEGF-C induces selective hyperplasia of the lymphatic vasculature, which is involved in the draining of interstitial fluid and in immune function, inflammation, and tumor metastasis. VEGF-C may play a role in disorders involving the lymphatic system and may be of potential use in therapeutic lymphangiogenesis.     

Built-in Self Testing of Embedded Memories

The authors present a built-in self-test (BIST) method for testing embedded memories. Two algorithms are proposed for self-testing of embedded bedded RAMs, both of which can detect a large variety of stuck-at and non-stuck-at faults. The hardware implementation of the methods requires a hardware test-pattern generator, which produces address, data, and read/write inputs. The output responses of the memory can be compressed by using a parallel input signature analyzer, or they can be compared with expected responses by an output comparator. The layout of memories has been considered in the design of additional BIST circuitry. The authors conclude by evaluating the two schemes on the basis of area overhead, performance degradation, fault coverage, test application time, and testing of self-test circuitry. The BIST overhead is very low and test time is quite short. Six devices, with one of the test schemes, have been manufactured and are in the field.     

Stabilisation of external optical feedback phase in a semiconductor laser

The linewidth of a semiconductor laser was reduced and held to much less than 1 MHz using a simple DC scheme for the stabilisation of the phase of external optical feedback. This scheme was based on the antisymmetric response to feedback phase at the two laser facets.     

Surface structural investigations on (100) and (110) faces of flux-grown lanthanum borate crystals

Results of topographical studies carried out on (100) and (110) faces of lanthanum borate crystals grown from the PbO-B₂O₃ flux system are illustrated and discussed. The habit faces display the formation of cavities, microcrystals, elliptical etch pits, elliptical hillocks, circular hillocks and irregular structures. Also described are a various number of elevated structures identified as impurity phases. Energy dispersive X-ray (EDAX) studies have confirmed that these impurity phases in the growth of lanthanum borate (LaBO₃) crystals are enriched by lead (Pb). The habit faces also exhibit some elevated regions which are reported to be more imperfect in comparison with others. It is inferred that independent growth on the habit faces has taken place during the last stage of crystal growth by a two-dimensional nucleation mechanism.     

Effectiveness factor under cyclic operation of a reactor

Results are reported on the influence of intraparticle diffusion on the measured rate of reaction under a condition where the feed composition is changing periodically. The specific application is to cyclic operation of an ammonia synthesis reactor. The effectiveness factor calculated relative to the steady-state kinetic rates for the time-average feed condition for fine particles was higher than the comparable steady-state effectiveness factor as a result of the rate improvement due to cycling. The effectiveness factor calculated relative to the time-average rate of reaction under cyclic operation for the fine particles was much less than unity and similar numerically to the steady-state effectiveness factor. The cycling effectiveness factor by either definition varied with cycling conditions because of the complex interaction of cycling parameters.     

Creation of Ferroelectric, Single-Crystal Architecture in Sm0.5La0.5BGeO5 Glass

Using a novel, selective heating by Nd:YAG laser, a single-crystal architecture is created in a model glass system, Sm_0.5La_0.5BGeO₅, which devitrifies congruently into a ferroelectric phase of the same composition as the parent glass. The Sm³⁺ ions in glass absorb the light and heat the matrix locally resulting in devitrification. Initially, a polycrystalline spot is formed. However, with optimum laser power, scanning speed, and the depth of focus, one of the grains acts as the seed for further growth as a single crystal. By programming the relative displacement of the glass with respect to laser spot, desired single ferroelectric crystal architecture is created. The optical functionalities (guiding of light and second harmonic generation) of the architectures are shown, which demonstrate the viability of this method for constructing active elements in optical integrated circuits. The single-crystal nature of the architecture is confirmed from the electron backscattered diffraction results.     

Social problem solving as a mediator of the stress-pain relationship among individuals with noncardiac chest pain.

Objective: The present study tested the hypothesis that social problem solving (SPS) served to mediate the relationship between preceived stress and noncardiac chest pain (NCCP). Design: Adults undergoing stress myocardial perfusion imaging (MPI) to determine the presence of underlying cardiovascular disease related to the experience of chest pain were recruited prior to stress testing to complete a series of self-report inventories. Main Outcome Measures: MPI results were used to identify individuals with NCCP (N = 166; 91 men, 75 women; mean age = 53.92 years, SD = 11.98). Measures included perceived stress, SPS, and chest pain frequency and intensity. Results: In direct tests of the mediational effects of SPS, it was found that two problem-solving dimensions, negative problem orientation and rational problem solving, each served as significant mediators of the effects of stress on both NCCP intensity and frequency. Conclusion: These results support a mediational analysis of NCCP that includes stress and SPS. As such, it identifies SPS as a potentially important clinical target to consider when developing future psychosocial-based therapy protocols for treating individuals with NCCP. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-started voltage-source series-resonant converter forhigh-power induction heating and melting applications

An inverter configuration for high-power induction heating and melting applications is presented. The proposed inverter covers loads with quality factors up to 12, while featuring self-starting capabilities. This is achieved by properly distributing the compensated capacitor between the primary and the secondary of the matching transformer. The transient analysis of the configuration defines the maximum ratio of the primary and secondary capacitors, in order to assure self starting. On the other hand, the steady-state analysis defines the minimum ratio to limit the operating flux level of the matching transformer to a safe level. This paper identifies the sources of self-starting failures in the standard configuration and presents the transient and steady-state analyses toward a systematic procedure of components design for the proposed topology. Experimental results on a laboratory prototype to prove the theoretical considerations are also included     

Cell formation in flexible manufacturing systems under resource constraints

In this paper, the cell formation problem in Flexible Manufacturing Systems under resource constraints is discussed. A 0–1 integer programming model is developed to form the machine-part groups and to decide on the number of machines and the number of copies of tools required to achieve minimum overall system cost. The model takes into account the processing time available on any machine, tool lives and the processing requirements of the parts. The model is illustrated using a numerical example.