Design and Implementation of a Low Complexity VLSI Turbo-Code Decoder Architecture for Low Energy Mobile Wireless Communications

Channel coding is commonly incorporated to obtain sufficient reception quality in wireless mobile communications transceiver to counter channel degradation due to intersymbol interference, multipath dispersion, and thermal noise induced by electronic circuit devices. For low energy mobile wireless communications, it is highly desirable to incorporate a decoder which has a very low power consumption while achieving a high coding gain. In this paper, a sub-optimal low-complexity multi-stage pipeline decoder architecture for a powerful channel coding technique known as “turbo-code” is presented. The presented architecture avoids complex operations such as exponent and logarithmic computations. The turbo-code decoding algorithm is reformulated for an efficient VLSI implementation. Furthermore, the communication channel statistic estimation process has been completely eliminated. The architecture has been designed and implemented with the 0.6 μm CMOS standard cell technology using Epoch computer aided design tool. The performance and the circuit complexity of the turbo-code decoder are evaluated and compared with the other types of well-known decoders. The power consumption of the low-complexity turbo-code decoder is comparable to that of the conventional convolutional-code decoder. However, the low-complexity turbo-code decoder has a significant coding gain over the conventional convolutional-code decoders and it is well suited for very low power applications.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41335/1/11265_2004_Article_253264.pd

Various Security Analysis of a pfCM-MD Hash Domain Extension and Applications based on the Extension

We propose a new hash domain extension \textit{a prefix-free-Counter-Masking-MD (pfCM-MD)}. And, among security notions for the hash function, we focus on the indifferentiable security notion by which we can check whether the structure of a given hash function has any weakness or not. Next, we consider the security of HMAC, two new prf constructions, NIST SP 800-56A key derivation function, and the randomized hashing in NIST SP 800-106, where all of them are based on the pfCM-MD. Especially, due to the counter of the pfCM-MD, the pfCM-MD are secure against all of generic second-preimage attacks such as Kelsey-Schneier attack \cite{KeSc05} and Elena {\em et al.}\u27 attck \cite{AnBoFoHoKeShZi08}. Our proof technique and most of notations follow those in \cite{BeDaPeAs08,Bellare06,BeCaKr96a}

Indifferentiable Security Analysis of choppfMD, chopMD, a chopMDP, chopWPH, chopNI, chopEMD, chopCS, and chopESh Hash Domain Extensions

We provide simple and unified indifferentiable security analyses of choppfMD, chopMD, a chopMDP (where the permutation $P$ is to be xored with any non-zero constant.), chopWPH (the chopped version of Wide-Pipe Hash proposed in \cite{Lucks05}), chopEMD, chopNI, chopCS, chopESh hash domain extensions. Even though there are security analysis of them in the case of no-bit chopping (i.e., $s=0$), there is no unified way to give security proofs. All our proofs in this paper follow the technique introduced in \cite{BeDaPeAs08}. These proofs are simple and easy to follow

Human macrophage polarization in the response to

Infection with Mycobacterium leprae, the causative organism of leprosy, is still endemic in numerous parts of the world including the southwestern United States. The broad variation of symptoms in the leprosy disease spectrum range from the milder tuberculoid leprosy (paucibacillary) to the more severe and disfiguring lepromatous leprosy (multibacillary). The established thinking in the health community is that host response, rather than M. leprae strain variation, is the reason for the range of disease severity. More recent discoveries suggest that macrophage polarization also plays a significant role in the spectrum of leprosy disease but to what degree it contributes is not fully established. In this study, we aimed to analyze if different strains of M. leprae elicit different transcription responses in human macrophages, and to examine the role of macrophage polarization in these responses. Genomic DNA from three different strains of M. leprae DNA (Strains NHDP, Br4923, and Thai-53) were used to stimulate human macrophages under three polarization conditions (M1, M1-activated, and M2). Transcriptome analysis revealed a large number of differentially expressed (DE) genes upon stimulation with DNA from M. leprae strain Thai-53 compared to strains NHDP and Br4923, independent of the macrophage polarization condition. We also found that macrophage polarization affects the responses to M. leprae DNA, with up-regulation of numerous interferon stimulated genes. These findings provide a deeper understanding of the role of macrophage polarization in the recognition of M. leprae DNA, with the potential to improve leprosy treatment strategies

Construction of Bacillus thuringiensis simulant strains suitable for environmental release

For a surrogate bacterium to be used in outdoor studies, it is important to consider environmental and human safety and ease of detection. Recently, Bacillus thuringiensis, a popular bioinsecticide bacterium, has been gaining attention as a surrogate bacterium for use in biodefense. In this study, we constructed simulant strains of B. thuringiensis with enhanced characteristics for environmental studies. Through transposon mutagenesis, pigment genes were inserted into the chromosome, producing yellow-colored colonies for easy detection. To prevent persistence of spores in the environment, a genetic circuit was designed to produce a spore without sporulation capability. Two loxP sites were inserted, one on each side of the spo0A gene, which encodes a sporulation master regulator, and a sporulation-dependent Cre expression cassette was inserted into the chromosome. This genetic circuit successfully deleted spo0A during sporulation, producing spores that lacked the spo0A gene. In addition, two major α/β-type small acid-soluble spore protein (SASP) genes, predicted by synteny analysis, were deleted. The spores of the mutant strain showed increased UV-C sensitivity and quickly lost viability when tested in a solar simulator. When the spores of the mutant strain were administered to the lungs of BALB/c mice, cells were quickly removed from the body, suggesting enhanced in vivo safety. All strains constructed in this study contain no antibiotic resistance markers and all heterologous genes were inserted into the chromosome, which are useful features for simulants to be released into the environment

Performance driven VLSI system design for low energy wireless communications.

The advent of mobile wireless communications has generated increased demand for long lasting portable device operation, and consequently, system power dissipation has become an important design metric. This dissertation presents a design methodology for reducing the power consumption of several critical aspects of wireless communication system while achieving a desired level of performance. In particular, the design methodology focuses on the architectural and algorithmic optimization of synchronization techniques and decoding algorithms. First, a low-power multiplier design methodology for DSP and communication system applications is proposed. Then, the front-end digital components such as a matched filter and a fast Fourier transform, which are integral part of the demodulation and synchronization, are optimized for low-power. Also, a low-complexity synchronization technique for a hybrid spread-spectrum system is developed and analyzed which supports frequency hopping and variable spreading gain transmission. In addition, an efficient synchronization scheme is developed with low-complexity physical realization for multi-carrier spread-spectrum system. This dissertation also discussed the importance of channel coding and presented a low-complexity architecture and its low-power VLSI implementation for a turbo-code. Finally, a system level power optimization method is presented where the selection of algorithms and choice of accuracy are determined to minimize the overall power dissipation through power-performance tradeoff analysis.Ph.D.Applied SciencesElectrical engineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/132375/2/9963806.pd

The Bc(1) Complex of Rhodobacter Sphaeroides and Its Integration Into the Photosynthetic Chain

165 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998.In this thesis, the effects of two inhibitors, funiculosin and zinc, on the bc\sb1 complex of Rhodobacter sphaeroides, and the role of isocyt c\sb2 in the photosynthetic chain were studied. Also the organization of the photosynthetic electron transfer chain of Rb. sphaeroides and the role of PufX were investigated. In Rb. sphaeroides, a bulky Val residue at position 209 in the bc\sb1 complex has been shown to provide the resistance to funiculosin. The mutation of Val209 to the smaller Ala allows funiculosin binding at the Q\sb0-site, and the additional change of Ile213 to Leu potentiates this effect. The effects of funiculosin on the Q\sb0-site of the bc\sb1 complex in the mutant strains suggest that changes in structural packing close to the Q\rm\sb{i}-site exert a relatively long-range secondary effect. Zinc inhibits the bc\sb1, complex of Rb. sphaeroids by binding a single inhibition site at the Q\sb0-site. But, when the bc\sb1, complex is embedded in the membrane, it is shielded from the inhibitory effect of zinc by the presence phospholipids in membranes, which interact with zinc ions, and compete effectively until the binding site are saturated. Isocyt c\sb2 has been shown to replace cyt c\sb2, and allow the system to undergo rapid electron transfer with kinetics similar to wild type in spite of its low concentration in cells and chromatophores, suggesting rapid diffusion of isocyt c\sb2,between several chains. Structural models of PufX suggest that it forms a dimer, providing a gate in LH1. The kinetic data also suggest two permeation pathways of quinone through the LH1; one using PufX and another less efficient pathway that depends on disorder in the LH1 palisade. Two models for the organization of photosynthetic electron transfer chain in Rb. sphaeroides, supercomplex model and heterogeneity model were examined with wild type and overproducer strains of Rb. sphaeroides. No fixed stoichiometry of photosynthetic components, and the dependence of the equilibrium constants on the light intensity and the type of inhibitors were explained more simply with the heterogeneity model rather than supercomplex model. The heterogeneity model was also consistent with the data suggesting a role for PufX.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD