Cad for analysis and synthesis of MM-wave transmission lines

This work presents a software for analysis and synthesis of four types of planar lines used on the millimeter wave band: Suspended Microstrip Line, Inverted Microstrip Line, Suspended Stripline and Broadside Coupled Stripline. Conceived for IBM/PG or compatible microcomputers, the program, (MMWL), can study each configuration at a time or all of them at once, and it does not matter if it is synthesis or analysis for each line at the same time. The results are presented in Tables shown in the same screen. The program also provides curves of characteristic impedances against conducting strip width for each one of studied structures. Therefore, it allows choosing the best combination for circuit realization, becoming a helpful tool for projects and with acceptable results.

     

Analysis of Antennas with PBG Substrate

The use of photonic materials has been used in the theory of optical waves. The PBG (Photonic Band Gap) theory and material, was developed recently for optical frequencies and can be easily applied to millimeter waves, microwaves and planar antenna frequencies. The presence of photonic materials as substrate in antennas has some good characteristics such as, supression of light spontaneous emission and suppression of surface waves, allowing the application in planar antenna array. In this work an elaborate analysis using the full wave Transverse Transmission Line - TTL method, that provides efficient and concise results is applied to the planar antennas array with PBG substrate.     

Discovering interobserver variability in the cytodiagnosis of breast cancer using decision trees and Bayesian networks

We evaluate the performance of two decision tree procedures and four Bayesian network classifiers as potential decision support systems in the cytodiagnosis of breast cancer. In order to test their performance thoroughly, we use two real-world databases containing 692 cases and 322 cases collected by a single observer and 19 observers, respectively. The results show that, in general, there are considerable differences in all tests (accuracy, sensitivity, specificity, PV+, PV− and ROC) when a specific classifier uses the single-observer dataset compared to those when this same classifier uses the multiple-observer dataset. These results suggest that different observers see different things: a problem known as interobserver variability. We graphically unveil such a problem by presenting the structures of the decision trees and Bayesian networks resultant from running both databases.     

The use of sugar cane stillage for single cell protein production

Stillage from cane molasses alcohol for SCP production was used for the growth of strains of Candida and Paecilomyces as SCP sources. The results of small and large scale experiments carried out with a Candida utilis strain with data on chemical composition, amino acid profile, vitamin content and biological value of the cell material are given.     

Photosynthetic production of Dunaliella biomass from natural salt water and carbon dioxide

A Dunaliella strain has been isolated and grown in a medium containing saline lake water. Using 40% saline water and mixture of CO₂-air (4% CO₂) the algae grew with a specific growth rate of 0.073 h⁻¹. The maximum cell concentration was 5.6 × 10⁷ cells cm⁻³ which corresponded to 3.63 g dm⁻³ of dry biomass. Using 80% saline water, a glycerol concentration of 1.47 g glycerol g⁻¹ of, protein was obtained which amounted to 44.3% of Dunaliella dry weight. Fermentor CO₂ from a continuous yeast culture was also used as carbon source for photosynthetic growth. At 2.5% CO₂ in the exit gas a decrease of the specific growth rate was observed but the final concentration attained was comparable to that obtained with CO₂-air mixtures.     

Using an image-extended relational database to support content-based image retrieval in a PACS

This paper presents a new Picture Archiving and Communication System (PACS), called cbPACS, which has content-based image retrieval capabilities. The cbPACS answers range and k-nearest- neighbor similarity queries, employing a relational database manager extended to support images. The images are compared through their features, which are extracted by an image-processing module and stored in the extended relational database. The database extensions were developed aiming at efficiently answering similarity queries by taking advantage of specialized indexing methods. The main concept supporting the extensions is the definition, inside the relational manager, of distance functions based on features extracted from the images. An extension to the SQL language enables the construction of an interpreter that intercepts the extended commands and translates them to standard SQL, allowing any relational database server to be used. By now, the system implemented works on features based on color distribution of the images through normalized histograms as well as metric histograms. Metric histograms are invariant regarding scale, translation and rotation of images and also to brightness transformations. The cbPACS is prepared to integrate new image features, based on texture and shape of the main objects in the image.     

Atomic nanotube welders: boron interstitials triggering connections in double-walled carbon nanotubes

Here we demonstrate that the incorporation of boron (B) atoms between double-walled carbon nanotubes (DWNTs) during thermal annealing (1400-1600 degrees C) results in covalent nanotube "Y" junctions, DWNT coalescence, and the formation of flattened multiwalled carbon nanotubes (MWNTs). These processes occur via the merging of adjacent tubes, which is triggered by B interstitial atoms. We observe that B atom interstitials between DWNTs are responsible for the rapid establishment of covalent connections between neighboring tubes (polymerization), thereby resulting in the fast annealing of the carbon cylinders with B atoms embedded in the newly created carbon nanotube network. Once B is in the lattice, tube faceting (polygonization) starts to occur, and the electronic properties are expected to change dramatically. Therefore, B atoms indeed act as atomic nanotube fusers (or welders), and this process could now be used in assembling novel electronic nanotube devices, nanotube networks, carbon nanofoams and heterojunctions exhibiting p-type electronic properties.     

Associative Gray Level Pattern Processing using Binary Decomposition and α β Memories

In this note we show how a binary memory can be used to recall gray-level patterns. We take as example the α β associative memories recently proposed in Yáñez, Associative Memories based on order Relations and Binary Operators(In Spanish), PhD Thesis, Center for computing Research, February of 2002, only useful in the binary case. Basically, the idea consists on that given a set of gray-level patterns to be first memorized: (1) Decompose them into their corresponding binary patterns, and (2) Build the corresponding binary associative memory (one memory for each binary layer) with each training pattern set (by layers). A given pattern or a distorted version of it, it is recalled in three steps: (1) Decomposition of the pattern by layers into its binary patterns, (2) Recalling of each one of its binary components, layer by layer also, and (3) Reconstruction of the pattern from the binary patterns already recalled in step 2. The proposed methodology operates at two phases: training and recalling. Conditions for perfect recall of a pattern either from the fundamental set or from a distorted version of one them are also given. Experiments where the efficiency of the proposal is tested are also given.     

High-bandwidth Address Generation Unit

In this paper we present an efficient data fetch circuitry to retrieve several operands from a n-way parallel memory system in a single machine cycle. The proposed address generation unit operates with an improved version of the low-order parallel memory access approach. Our design supports data structures of arbitrary lengths and different odd strides. The experimental results show that our address generation unit is capable of generating eight 32 − bit addresses every 6 ns for different strides when implemented on a VIRTEX-II PRO xc2vp30-7ff1696 FPGA device using only trivial hardware resources.