Some Results on Convolutional Coupled Codes: Distance Properties, Performance, and Design

The class of Convolutional Coupled Codes is a promising alternative to classical Turbo-Codes. A Convolutional Coupled Code consists of a cascade of ν identical recursive systematic convolutional (RSC) outer codes and k inner block codes with parameters (2ν, ν, d_i). The codes are linked together such that only the systematic part of the outer codes is encoded with the inner block encoders. Only the redundancy from the inner and outer codes are transmitted. An estimation of the minimum distance is derived. The influence of number, code memory and code polynomials of the outer RSC codes on the distance properties and the convergence behavior of the iterative decoding scheme is studied. With respect to this results, we present a guideline for the optimal design of the RSC outer codes.     

The Prediction of Bubble-point Pressure and Bubble-point Oil Formation Volume Factor in the Absence of PVT Analysis

Up to now, there has not been one specific correlation published to directly estimate the bubble-point pressure in the absence of pressure-volume-temperature (PVT) analysis. Presently, there is just one published correlation available to estimate the bubble-point oil formation volume factor (FVF) directly in the absence of PVT analysis. Multiple regression analysis technique is applied to develop two novel correlations to estimate the bubble-point pressure and the bubble-point oil FVF. The developed correlations can be applied in a straightforward manner by using direct field measurement data. Separator gas oil ratio, separator pressure, stock-tank oil gravity, and reservoir temperature are the only key parameters required to predict bubble-point pressure and bubble-point oil FVF.     

On the feedback error compensation for adaptive modulation and coding scheme

In this paper, we consider the effect of feedback error on the performance of the joint adaptive modulation and diversity combining (AMDC) scheme which was previously studied with an assumption of perfect feedback channels. We quantify the performance of two joint AMDC schemes in the presence of feedback error, in terms of the average spectral efficiency, the average number of combined paths, and the average bit error rate. The benefit of feedback error compensation with adaptive combining is also quantified. Selected numerical examples are presented and discussed to illustrate the effectiveness of the proposed feedback error compensation strategy with adaptive combining. Copyright © 2011 John Wiley & Sons, Ltd.     

Feature construction as a bi-level optimization problem

Neural Computing and Applications - Feature selection and construction are important preprocessing techniques in data mining. They allow not only dimensionality reduction but also classification...     

Deriving business processes with service level agreements from early requirements

When designing a service-based business process employing loosely coupled services, one is not only interested in guaranteeing a certain flow of work, but also in how the work will be performed. This involves the consideration of non-functional properties which go from execution time and costs, to trust and security. Ideally, a designer would like to have guarantees over the behavior of the services involved in the process. These guarantees are the object of Service Level Agreements.We propose a methodology to design service-based business processes together with Service Level Agreements that guarantee a certain quality of execution, with particular emphasis on security. Starting from an early requirements analysis modeled in the Secure Tropos formalism, we provide a set of user-guided transformations and reasoning tools the final output of which is a set of processes in the form of Secure BPELs together with a set of Service Level Agreements to be signed by participating services. To show the potential impact of the approach, we illustrate the functioning of the methodology on a collaborative procurement scenario derived from the application domain of a research project.     

An Efficient Method for the Synthesis of Some New and Known Polyhydroxyl Aromatic Compounds (Trisphenols) under Solvent-free Conditions

A simple, rapid, green, and highly efficient method for the synthesis of substituted trisphenols is described from the reaction of 2,6-bis (methylol) phenols (BMP) and different substituted phenols in the presence of a nanosilica supported dual acidic ionic liquid (NSSDAIL), supported 1-methyl-3-(4-sulfobutyl) imidazolium hydrogen sulfate, as catalyst under solvent-free conditions. This reaction allowed us to prepare some new and known derivatives of substituted trisphenols. This procedure is a clean and environmentally friendly approach to prepare different 2,6-bis(2-hydroxy benzyl) phenol derivatives that offers many advantages, including short reaction times and high yield of the products, use a non corrosive and reusable catalyst and solvent-free conditions.     

Plasma Heating of Carbonate Formations

Calcium carbonate rock samples were exposed to high temperature argon plasma to investigate the efficiency of plasma heating for fracturing carbonate formations. Plasma temperature can change the basic properties of the rock through fracture and calcination, which in turn can result in a significant increase in its porosity and permeability. Several calcium carbonate cores with a diameter of 25.4 mm and a height of 29 mm were subjected to axial plasma heating at different temperatures and for different periods of time. The experimental results indicated that the top surface temperatures of the samples ranged from 800°C to 900°C and the temperature reached steady state within 4 min. The scanning electron microscope (SEM) and porosity analysis of the treated samples indicated significant changes in the basic structure of the rocks and a substantial increase in both porosity and permeability. A mathematical model was developed to predict the temperature distribution along the axis of the heated sample and to estimate the time needed to achieve steady state. The model predictions were in good agreement with experimental results.     

On Convolutional Coupled Codes

The error correcting performance of the parallel concatenation of two convolutional codes is very promising. Inspired from this construction which is near the Shannon limit error correction performance, we consider a further development of concatenated codes. In this construction systematic convolutional codes and rate 1/2 systematic block codes are linked together such that only the systematic part of the convolutional codes is encoded with the block encoders. The bits of each information vector of the convolutional codes are scrambled by a given interleaving before entering to the block encoders. Then, differently from the Turbo codes, in which information symbols and the redundancy from the constituent codes are transmitted [1], we transmit only the redundancy from the convolutional and block codes. We call this construction convolutional coupled codes and code coupling is the new scheme of code concatenation. The structural properties of the generator matrix of the convolutional coupled code is investigated. It's minimum distance is lower and upper bounded and we introduce the term of the effective free distance. Simulation results will show, that convolutional coupled codes have the potential of being a realistic alternative to Turbo codes.     

Bowel endometriosis. Eight cases of colorectal resection

Colo-rectal endometriosis requiring colon resection are reported in 8 patients to illustrated the diagnostic and therapeutic problems encountered in the management of this uncommon localisation. Pericatamenial or catamenial bowel symptoms associated with pelvic genital involvement were encountered in all cases. Clinical examination, barium enema and colonoscopy are essential to guide surgical management looking for multiple localisations. However their diagnostic value is low as endometriosis rarely involves the mucosa. Endosonography appears to be very promising in evaluating the depth of infiltration of the bowel. The treatment of bowel endometriosis is controversial and varies greatly according to the patient's complaints and clinical data. The indications and limits of all treatment modalities including abstention, medical, and surgical treatment are discussed. From the cases reported we conclude that symptomatic bowel endometriosis should be fully excised whenever possible, and the surgical procedure should be adapted to the depth of infiltration. A full thickness excision or bowel resection is mandatory in patients with deep muscularis involvement. These procedures, which are often difficult due to extensive fibrosis and adhesions, may be achieved by laparoscopy in selected patients.     

A new technique for treatment of permeability damage due to asphaltene deposition using laser technology

This study proposes a new technique for cleaning deposited asphaltenes using laser energy. Two series of experiments were carried out to achieve this objective. In the first one, one-inch column of bitumen mixed with limestone was placed above powdered limestone column in a flow cell. In the second series of experiments, actual consolidated limestone cores were subjected to flow of asphaltenic crude oil to simulate the damage process (i.e. permeability reduction). Both unconsolidated and consolidated limestone samples were subjected to a laser energy using laboratory diode modules at various laser intensity and treatment time intervals.Experimental results indicated that exposure of the above-mentioned permeability damaged limestone samples to laser energy caused asphaltene disruption and resulted in recovery of damaged permeability. The increase of laser intensity increased the recovered permeability and the optimum time duration is measured to be 1 h at laser intensity of 19 mW/h. Simultaneous pumping is required during the laser treatment to avoid the re-precipitation of the disrupted asphaltene.