Near-capacity turbo trellis coded modulation design based on EXIT charts and union bounds - [transactions papers]

Bandwidth efficient parallel-concatenated Turbo Trellis Coded Modulation (TTCM) schemes were designed for communicating over uncorrelated Rayleigh fading channels. A symbol-based union bound was derived for analysing the error floor of the proposed TTCM schemes. A pair of In-phase (I) and Quadrature-phase (Q) interleavers were employed for interleaving the I and Q components of the TTCMcoded symbols, in order to attain an increased diversity gain. The decoding convergence of the IQ-TTCM schemes was analysed using symbol-based EXtrinsic Information Transfer (EXIT) charts. The best TTCM component codes were selected with the aid of both the symbolbased union bound and non-binary EXIT charts, for designing capacity-approaching IQ-TTCM schemes in the context of 8PSK, 16QAM, 32QAM and 64QAM modulation schemes.     

Isoconversional kinetic analysis of the crystallization phases of amorphous selenium thin films

The crystallization kinetics of Se thin films were determined under nonisothermal conditions using a differential scanning calorimetry (DSC) technique. The development of crystal phases by thermal treatment of the film at various temperatures was analyzed by X-ray diffraction. Microstructures were identified by studying the morphology of the films using scanning electron microscopy and atomic force microscopy. This study reveals the simultaneous presence of distinct hexagonal and monoclinic phases; the DSC crystallization curve is formed by overlapping the exothermic crystallization curves of both phases. Two isoconversional methods, the Kissinger-Akahira-Sunose and Vyazovkin methods, were used to determine the variation of the activation energy for crystallization with temperature. The results show that the crystallization activation energy decreases with the extent of crystallization or temperature, which suggests that the examined phases follow multi-step kinetics.     

A Turbo Detection and Sphere-Packing-Modulation-Aided Space-Time Coding Scheme

A recently proposed space-time block-coding (STBC) signal-construction method that combines orthogonal design with sphere packing (SP), referred to here as STBC-SP, has shown useful performance improvements over Alamouti's conventional orthogonal design. In this contribution, we demonstrate that the performance of STBC-SP systems can be further improved by concatenating SP-aided modulation with channel coding and performing demapping as well as channel decoding iteratively. We also investigate the convergence behavior of this concatenated scheme with the aid of extrinsic-information-transfer charts. The proposed turbo-detected STBC-SP scheme exhibits a "turbo-cliff" at E_b/N₀=2.5 dB and provides E_b/N₀ gains of approximately 20.2 and 2.0 dB at a bit error rate of 10 ^-5 over an equivalent-throughput uncoded STBC-SP scheme and a turbo-detected quadrature phase shift keying (QPSK) modulated STBC scheme, respectively, when communicating over a correlated Rayleigh fading channel.A condensed version of this paper was presented at VTC'04 Fall, LA, USA     

Microstructural,mechanical, and thermal characteristics of recycled cellulose fiber‐halloysite‐epoxy hybrid nanocomposites

Epoxy hybrid‐nanocomposites reinforced with recycled cellulose fibers (RCF) and halloysite nanotubes (HNTs) have been fabricated and investigated. The dispersion of HNTs was studied by synchrotron radiation diffraction (SRD) and transmission electron microscopy (TEM). The influences of RCF/HNTs dispersion on the mechanical properties and thermal properties of these composites have been characterized in terms of flexural strength, flexural modulus, fracture toughness, impact toughness, impact strength, and thermogravimetric analysis. The fracture surface morphology and toughness mechanisms were investigated by SEM. Results indicated that mechanical properties increased because of the addition of HNTs into the epoxy matrix. Flexural strength, flexural modulus, fracture toughness, and impact toughness increased by 20.8, 72.8, 56.5, and 25.0%, respectively, at 1 wt% HNTs load. The presence of RCF dramatically enhanced flexural strength, fracture toughness, impact strength, and impact toughness of the composites by 160%, 350%, 444%, and 263%, respectively. However, adding HNTs to RCF/epoxy showed only slight enhancements in flexural strength and fracture toughness. The inclusion of 5 wt% HNTs into RCF/epoxy ecocomposites increased the impact toughness by 27.6%. The presence of either HNTs or RCF accelerated the thermal degradation of neat epoxy. However, at high temperature, samples reinforced with RCF and HNTs displayed better thermal stability with increased char residue than neat resin. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers     

Breast Cancer Detection in Saudi Arabian Women Using Hybrid Machine Learning on Mammographic Images

Breast cancer (BC) is the most common cause of women’s deaths worldwide. The mammography technique is the most important modality for the detection of BC. To detect abnormalities in mammographic images, the Breast Imaging Reporting and Data System (BI-RADs) is used as a baseline. The correct allocation of BI-RADs categories for mammographic images is always an interesting task, even for specialists. In this work, to detect and classify the mammogram images in BI-RADs, a novel hybrid model is presented using a convolutional neural network (CNN) with the integration of a support vector machine (SVM). The dataset used in this research was collected from different hospitals in the Qassim health cluster of Saudi Arabia. The collection of all categories of BI-RADs is one of the major contributions of this paper. Another significant contribution is the development of a hybrid approach through the integration of CNN and SVM. The proposed hybrid approach uses three CNN models to obtain ensemble CNN model results. This ensemble model saves the values to integrate them with SVM. The proposed system achieved a classification accuracy, sensitivity, specificity, precision, and F1-score of 93.6%, 94.8%, 96.9%, 96.6%, and 95.7%, respectively. The proposed model achieved better performance compared to previously available methods.     

An Optimized Method for Accounting Information in Logistic Systems

In the era of rapid information development, with the popularity of computers, the advancement of science and technology, and the ongoing expansion of IT technology and business, the enterprise resource planning (ERP) system has evolved into a platform and a guarantee for the fulfilment of company management procedures after long-term operations. Because of developments in information technology, most manual accounting procedures are being replaced by computerized Accounting Information Systems (AIS), which are quicker and more accurate. The primary factors influencing the decisions of logistics firm trading parties are investigated in order to enhance the design of decision-supporting modules and to improve the performance of logistics enterprises through AIS. This paper proposed a novel approach to calculate the weights of each information element in order to establish their important degree. The main purpose of this research is to present a quantitative analytic approach for determining the important information of logistics business collaboration response. Furthermore, the idea of total orders and the significant degrees stated above are used to identify the optimal order of all information elements. Using the three ways of marginal revenue, marginal cost, and business matching degree, the information with cumulative weights is which is deployed to form the data from the intersection of the best order. It has the ability to drastically reduce the time and effort required to create a logistics business control/decision-making system.     

Lattice Transformation from 2D to Quasi 1D and Phonon Properties of Exfoliated ZrS2 and ZrSe2

Recent reports on thermal and thermoelectric properties of emerging 2D materials have shown promising results. Among these materials are Zirconium-based chalcogenides such as zirconium disulfide (ZrS₂), zirconium diselenide (ZrSe₂), zirconium trisulfide (ZrS₃), and zirconium triselenide (ZrSe₃). Here, the thermal properties of these materials are investigated using confocal Raman spectroscopy. Two different and distinctive Raman signatures of exfoliated ZrX₂ (where X = S or Se) are observed. For 2D-ZrX₂, Raman modes are in alignment with those reported in literature. However, for quasi 1D-ZrX₂, Raman modes are identical to exfoliated ZrX₃ nanosheets, indicating a major lattice transformation from 2D to quasi-1D. Raman temperature dependence for ZrX₂ are also measured. Most Raman modes exhibit a linear downshift dependence with increasing temperature. However, for 2D-ZrS₂, a blueshift for A1g mode is detected with increasing temperature. Finally, phonon dynamics under optical heating for ZrX₂ are measured. Based on these measurements, the calculated thermal conductivity and the interfacial thermal conductance indicate lower interfacial thermal conductance for quasi 1D-ZrX₂ compared to 2D-ZrX₂, which can be attributed to the phonon confinement in 1D. The results demonstrate exceptional thermal properties for Zirconium-based materials, making them ideal for thermoelectric device applications and future thermal management strategies.