Adaptive RS codes for message delivery over an encrypted mobile network

The authors present a hybrid automatic repeat request technique using adaptive Reed-Solomon (RS) codes with packet erasure. This technique suits the transport layer in tactical mobile wireless networks with type I encryption, where encryption erasures the entire Internet protocol packet. The novelty of the presented technique is the multifaceted optimisation of Reed-Solomon codes at the transport layer for delivery assurance, speed of service (SoS) and network throughput. With this technique, the transport layer in tactical networks can meet the stringent requirements of quality of service imposed by the tactical network user, even under adverse conditions. These requirements define a high level of reliability (delivery assurance), a specific SoS and optimum use of the limited bandwidth (BW) of the wireless network, where the probability of packet erasure can be very high. The provided probabilistic analysis shows that focusing on network throughput alone will result in violating SoS and delivery assurance requirements. On the other hand, focusing on SoS and delivery assurance requirements can result in poor network throughput. The multifaceted optimisation technique, which utilises hybrid ARQ for message delivery, is described using a homogeneous Markov chain.     

Joint lossless-source and channel coding using automatic repeatrequest

The susceptibility of arithmetic coding to errors is utilized for channel error recovery using an automatic repeat request (ARQ) scheme. The presented scheme optimizes the tradeoff between the redundancy added to overcome channel errors and detection capability. With this approach, the type of error pattern introduced by the channel does not affect the receiver's detection capability. This scheme is suitable for transmitting long files over low bit error rate channels, and it provides the assurance of reconstructing the original data, free from catastrophic errors     

MOS current mode circuits: analysis, design, and variability

The interest in MOS current-mode logic (MCML) is increasing because of its ability to dissipate less power than conventional CMOS circuits at high frequencies, while providing an analog friendly environment. Moreover, automated design methodologies are gaining attention by circuit designers to provide shorter design cycles and faster time to market. This paper provides designers with an insight to the different tradeoffs involved in the design of MCML circuits to efficiently and systematically design MCML circuits. A comprehensive analytical formulation for the design parameters of MCML circuits using the BSIM3v3 model is introduced. In addition, a closed-form expression for the noise margin of two-level MCML circuits is derived. In order to verify the validity of the analytical formulations, an automated design methodology for MCML circuits is proposed to overcome the complexities of the design process. The effectiveness of the design methodology and the accuracy of the analytical formulations are tested by designing several MCML benchmarks built in a 0.18-/spl mu/m CMOS technology. The error in the required performance in the designed circuits is within 11% when compared to HSPICE simulations. A worst case parameter variations modeling is presented to investigate the impact of variations on MCML circuits as well as designing MCML circuits for variability. Finally, the impact of variations on MCML circuits is investigated with technology scaling and different circuit architectures.     

Principles and applications of hyperspectral imaging in quality evaluation of agro-food products: a review

The requirements of reliability, expeditiousness, accuracy, consistency, and simplicity for quality assessment of food products encouraged the development of non-destructive technologies to meet the demands of consumers to obtain superior food qualities. Hyperspectral imaging is one of the most promising techniques currently investigated for quality evaluation purposes in numerous sorts of applications. The main advantage of the hyperspectral imaging system is its aptitude to incorporate both spectroscopy and imaging techniques not only to make a direct assessment of different components simultaneously but also to locate the spatial distribution of such components in the tested products. Associated with multivariate analysis protocols, hyperspectral imaging shows a convinced attitude to be dominated in food authentication and analysis in future. The marvellous potential of the hyperspectral imaging technique as a non-destructive tool has driven the development of more sophisticated hyperspectral imaging systems in food applications. The aim of this review is to give detailed outlines about the theory and principles of hyperspectral imaging and to focus primarily on its applications in the field of quality evaluation of agro-food products as well as its future applicability in modern food industries and research.     

Robust colour calibration of an imaging system using a colour space transform and advanced regression modelling

A new algorithm for the conversion of device dependent RGB colour data into device independent L*a*b* colour data without introducing noticeable error has been developed. By combining a linear colour space transform and advanced multiple regression methodologies it was possible to predict L*a*b* colour data with less than 2.2 colour units of error (CIE 1976). By transforming the red, green and blue colour components into new variables that better reflect the structure of the L*a*b* colour space, a low colour calibration error was immediately achieved (ΔE(CAL) = 14.1). Application of a range of regression models on the data further reduced the colour calibration error substantially (multilinear regression ΔE(CAL) = 5.4; response surface ΔE(CAL) = 2.9; PLSR ΔE(CAL) = 2.6; LASSO regression ΔE(CAL) = 2.1). Only the PLSR models deteriorated substantially under cross validation. The algorithm is adaptable and can be easily recalibrated to any working computer vision system. The algorithm was tested on a typical working laboratory computer vision system and delivered only a very marginal loss of colour information ΔE(CAL) = 2.35. Colour features derived on this system were able to safely discriminate between three classes of ham with 100% correct classification whereas colour features measured on a conventional colourimeter were not.     

Near-infrared hyperspectral imaging for grading and classification of pork

In this study, a hyperspectral imaging technique was developed to achieve fast, accurate, and objective determination of pork quality grades. Hyperspectral images were acquired in the near-infrared (NIR) range from 900 to 1700 nm for 75 pork cuts of longissimus dorsi muscle from three quality grades (PSE, RFN and DFD). Spectral information was extracted from each sample and six significant wavelengths that explain most of the variation among pork classes were identified from 2nd derivative spectra. There were obvious reflectance differences among the three quality grades mainly at wavelengths 960, 1074, 1124, 1147, 1207 and 1341 nm. Principal component analysis (PCA) was carried out using these particular wavelengths and the results indicated that pork classes could be precisely discriminated with overall accuracy of 96%. Algorithm was developed to produce classification maps of the tested samples based on score images resulting from PCA and the results were compared with the ordinary classification method. Investigation of the misclassified samples was performed and showed that hyperspectral based classification can aid in class determination by showing spatial location of classes within the samples.     

Low-power CMOS/BiCMOS drivers and receivers for on-chipinterconnects

Novel low-voltage swing CMOS and BiCMOS driver/receiver circuits for low-power VLSI applications are proposed. Interconnect wire drivers with low output signal swing are employed. Special receivers provide single and double level conversion while minimizing the total driver/receiver transmission delay. These level converters have no DC power dissipation. At 3.3 V power supply voltage, the proposed circuits consume less power without delay penalty. The power saving is observed to be as high as 30%. At lower supplies further power and delay improvements are observed     

Novel high speed circuit structures for BiCMOS environment

Novel high speed BiCMOS circuits including ECL/CMOS, CMOS/ECL interface circuits and a BiCMOS sense amplifier are presented. A generic 0.8 μm complementary BiCMOS technology has been used in the circuit design. Circuit simulations show superior performance of the novel circuits over conventional designs. The time delays of the proposed ECL/CMOS interface circuits, the dynamic reference voltage CMOS/ECL interface circuit and the BiCMOS sense amplifier are improved by 20, 250, and 60%, respectively. All the proposed circuits maintain speed advantage until the supply voltage is scaled down to 3.3 V     

VLSI compressor design with applications to digital neural networks

A key problem for implementing high-performance, high-capacity digital neural networks (DNN) is to design effective VLSI compressors to reduce the impact of carry propagation of large data matrix. In this paper, such a compressor design based on complex complementary pass-transistor logic (C²PL) is presented. Some types of 3-2 compressors in C²PL are implemented and a number of experiments are conducted to optimize their performance. Two typical building blocks, 4-2 and 7-3 compressors, are developed and their DNN applications are discussed. Compared with the complementary pass-transistor logic (CPL) and the conventional direct logic (CDL), our simulations show that the C²PL compressors have the best performance in power, delay and number of transistors     

Two new methods for constructing double-ended priority queues from priority queues

We introduce two data-structural transformations to construct double-ended priority queues from priority queues. To apply our transformations the priority queues exploited must support the extraction of an unspecified element, in addition to the standard priority-queue operations. With the first transformation we obtain a double-ended priority queue which guarantees the worst-case cost of O(1) for find-min, find-max, insert, extract; and the worst-case cost of O(lg n) with at most lg n + O(1) element comparisons for delete. With the second transformation we get a meldable double-ended priority queue which guarantees the worst-case cost of O(1) for find-min, find-max, insert, extract; the worst-case cost of O(lg n) with at most lg n + O(lg lg n) element comparisons for delete; and the worst-case cost of O(min {lg m, lg n}) for meld. Here, m and n denote the number of elements stored in the data structures prior to the operation in question. The work of the authors was partially supported by the Danish Natural Science Research Council under contracts 21-02-0501 (project Practical data structures and algorithms) and 272-05-0272 (project Generic programming—algorithms and tools). A. Elmasry was supported by Alexander von Humboldt fellowship.