Fast numerically stable computation of orthogonal Fourier?Mellin moments

An efficient algorithm for the computation of the orthogonal Fourier-Mellin moments (OFMMs) is presented. The proposed method computes the fractional parts of the orthogonal polynomials, which consist of fractional terms, recursively, by eliminating the number of factorial calculations. The recursive computation of the fractional terms makes the overall computation of the OFMMs a very fast procedure in comparison with the conventional direct method. Actually, the computational complexity of the proposed method is linear O(p) in multiplications, with p being the moment order, while the corresponding complexity of the direct method is O(p²). Moreover, this recursive algorithm has better numerical behaviour, as it arrives at an overflow situation much later than the original one and does not introduce any finite precision errors. These are the two major advantages of the algorithm introduced in the current work, establishing the computation of the OFMMs to a very high order as a quite easy and achievable task. Appropriate simulations on images of different sizes justify the superiority of the proposed algorithm over the conventional algorithm currently used     

Supply current testing in linear bipolar ICs

Fault detection in linear bipolar integrated circuits using power supply current measurements is investigated. The most prevalent, catastrophic and parametric faults, have been modelled for a representative (741 type) opamp. The circuit is simulated under both linear and nonlinear operation. Comparative results between power supply current and output voltage measurements are given, showing the improvement in fault coverage by the use of the current sensing method.<>     

Novel moment invariants for improved classification performance in computer vision applications

A novel set of moment invariants based on the Krawtchouk moments are introduced in this paper. These moment invariants are computed over a finite number of image intensity slices, extracted by applying an innovative image representation scheme, the image slice representation (ISR) method. Based on this technique an image is decomposed to a several non-overlapped intensity slices, which can be considered as binary slices of certain intensity. This image representation gives the advantage to accelerate the computation of image's moments since the image can be described in a number of homogenous rectangular blocks, which permits the simplification of the computation formulas. The moments computed over the extracted slices seem to be more efficient than the corresponding moments of the same order that describe the whole image, in recognizing the pattern under processing. The proposed moment invariants are exhaustively tested in several well known computer vision datasets, regarding their rotation, scaling and translation (RST) invariant recognition performance, by resulting to remarkable outcomes.     

Estimation of ambient temperature bin data from monthly average temperatures and solar clearness index. Validation of the methodology in two Greek cities

Ambient temperature bin data are used for estimating the energy consumption in HVAC systems with air-source heat pumps and cooling equipment. In this paper a methodology for estimating the ambient temperature bin data, based on monthly average outdoor temperatures and solar clearness index, is presented. For the two most populated cities of Greece, namely Athens and Thessaloniki, the estimated data are compared to the bin data produced by statistical analysis of 10 years hourly dry-bulb temperature measurements. Both data sets were also used for estimating the heating and cooling energy requirements of a case study building. The results obtained are similar, with very small differences, suggesting that the proposed methodology can be used for estimating bin data for other cities.     

Design,Synthesis, and in vitro Evaluation of P2X7 Antagonists

The P2X7 receptor is a promising target for the treatment of various diseases due to its significant role in inflammation and immune cell signaling. This work describes the design, synthesis, and in vitro evaluation of a series of novel derivatives bearing diverse scaffolds as potent P2X7 antagonists. Our approach was based on structural modifications of reported (adamantan-1-yl)methylbenzamides able to inhibit the receptor activation. The adamantane moieties and the amide bond were replaced, and the replacements were evaluated by a ligand-based pharmacophore model. The antagonistic potency of the synthesized analogues was assessed by two-electrode voltage clamp experiments, using Xenopus laevis oocytes that express the human P2X7 receptor. SAR studies suggested that the replacement of the adamantane ring by an aryl-cyclohexyl moiety afforded the most potent antagonists against the activation of the P2X7 cation channel, with analogue 2-chloro-N-[1-(3-(nitrooxymethyl)phenyl)cyclohexyl)methyl]benzamide ( 56 ) exhibiting the best potency with an IC₅₀ value of 0.39 μM.     

Oscillator analogy for modelling the manufacturing systems dynamics

The purpose of this paper is to present an approach of modelling and analysis of the dynamic behaviour of manufacturing systems. The manufacturing system is considered to be responding to an excitation, namely a demand that varies over time, by producing a number of parts over time. This resembles a mechanical system that displaces its mass responding to a varying input force. Based on this analogy, this paper establishes a manufacturing system's modelling method. A system identification technique is used for deriving inertia, damping and stiffness from the manufacturing system's response to different excitations. Based on these attributes, the response of a manufacturing system to any given input can be estimated. Furthermore, a definition for assessing manufacturing flexibility, based on this approach, is being discussed.     

Bin weather data for 38 Greek cities

Ambient temperature bin data are used for estimating the energy consumption for heating and cooling of buildings. This well-known method is a steady-state approach and the energy requirements are determined at various outdoor temperatures, in order to account for the effect of outside temperature on the HVAC equipment efficiency. The application of the method requires detailed bin data. In this paper, the dry-bulb temperature bin data for 38 Greek cities are determined by using a reliable estimating methodology, based on monthly-average outdoor temperatures and solar clearness index. The data are calculated from −18 °C to 42 °C with 2 °C increments in six daily 4-h shifts, and are presented in tabular form.     

Polymer thick-films on silicon: a route to hybrid microsystems

The integration of polymer thick-film transducers and silicon offers a low-cost technology for the fabrication of hybrid microsystems. This paper presents a study on the feasibility and processing parameters of this integration. Selected transducer films were printed on silicon wafers covered with aluminum or various passivation layers and also on alumina for comparison. The quality of film adhesion was investigated using standard tape pull and scratch tests. Scanning electron microscopy and energy dispersive X-ray spectra analysis were used to investigate the interface between the films and the substrates. It was found that the films did not contaminate the wafers. We also characterized the film resolution by researching the wetting behavior of the pastes and the quality of printed patterns. The influence of the substrate's thermal coefficient of expansion on the resistance of a carbon polymer film was also analyzed. The experiments showed that the same design rules can be applied on both alumina and silicon substrates. Furthermore, dry and wet methods of etching and cleaning wafers from the thick-films were assessed. An insight into the potential and limitations of the technology is developed by discussing the issues of bonding mechanism, silicon contamination and influence of substrate on the resolution, electrical properties and infrared curing of the films. A design methodology for hybrid microsystems is proposed along with a suggestion for potential applications     

Impact of the ambient temperature rise on the energy consumption for heating and cooling in residential buildings of Greece

Annual values of heating and cooling degree-days for two typical base temperatures, namely 15 °C for heating and 24 °C for cooling, and for the two main cities of Greece (Athens and Thessaloniki) from 1983 to 2002 are presented in the study, calculated using hourly dry bulb temperature records from the meteorological stations of the National Observatory of Athens and of the Aristotle University of Thessaloniki. The decade average (1983–1992 and 1993–2002) values of the heating and cooling degree-days of the two cities are compared, for various base temperatures. The results show that the average value of heating degree-days of Athens for the decade 1993–2002, depending on the base temperature, is reduced from 8% to 22% as compared to the corresponding value of the decade 1983–1992. Similarly, the reduction in the Thessaloniki case is found in the range 4.5%–9.5%. The difference in the average value of cooling degree-days of the decades is more pronounced, the increase ranging from 25% to 69% for Athens and from 10% to 21% for Thessaloniki. In order to evaluate the effect of these changes on the energy requirements for heating and cooling of a typical residential building, the latter were calculated using the variable base degree-day method and the data sets of the two decades. The results show a reduction of the heating energy demand by 11.5% and 5% and an increase of the cooling energy demand by 26% and 10%, for Athens and Thessaloniki respectively.     

Efficient and accurate computation of geometric moments on gray-scale images

A novel algorithm that permits the fast and accurate computation of geometric moments on gray-scale images is presented in this paper. The proposed algorithm constitutes an extension of the IBR algorithm, introduced in the past, which was applicable only for binary images. A new image representation scheme, the ISR (intensity slice representation), which represents a gray-scale image as an expansion of several two-level images of different intensity values, enables the partially application of the IBR algorithm to each image component. Moreover, using the resulted set of image blocks, the geometric moments’ computation can be accelerated through appropriate computation schemes.