비만아 부모의 돌봄 경험: q 방법론

After two decades of research and development, elliptic curve cryptography now has widespread exposure and acceptance. Industry, banking, and government standards are in place to facilitate extensive deployment of this efficient public-key mechanism. Anchored by a comprehensive treatment of the practical aspects of elliptic curve cryptography (ECC), this guide explains the basic mathematics, describes state-of-the-art implementation methods, and presents standardized protocols for public-key encryption, digital signatures, and key establishment. In addition, the book addresses some issues that arise in software and hardware implementation, as well as side-channel attacks and countermeasures. Readers receive the theoretical fundamentals as an underpinning for a wealth of practical and accessible knowledge about efficient application. Features & Benefits: * Breadth of coverage and unified, integrated approach to elliptic curve cryptosystems * Describes important industry and government protocols, such as the FIPS 186-2 standard from the U.S. National Institute for Standards and Technology * Provides full exposition on techniques for efficiently implementing finite-field and elliptic curve arithmetic* Distills complex mathematics and algorithms for easy understanding* Includes useful literature references, a list of algorithms, and appendices on sample parameters, ECC standards, and software toolsThis comprehensive, highly focused reference is a useful and indispensable resource for practitioners, professionals, or researchers in computer science, computer engineering, network design, and network data security.

https://cdn.preterhuman.net/texts/cryptography/Hankerson,%20Menezes,%20Vanstone.%20Guide%20to%20elliptic%20curve%20cryptography%20(Springer,%202004)(ISBN%20038795273X)(332s)_CsCr_.pdf

Guide to Elliptic Curve Cryptography

National Institute of Standards and Technology における超伝導研究及び生活

Most of the signal processing that we will study in this course involves local operations on a signal, namely transforming the signal by applying linear combinations of values in the neighborhood of each sample point. You are familiar with such operations from Calculus, namely, taking derivatives and you are also familiar with this from optics namely blurring a signal. We will be looking at sampled signals only. Let's start with a few basic examples. Local difference Suppose we have a 1D image and we take the local difference of intensities, DI(x) = 1 2 (I(x + 1) − I(x − 1)) which give a discrete approximation to a partial derivative. (We compute this for each x in the image.) What is the effect of such a transformation? One key idea is that such a derivative would be useful for marking positions where the intensity changes. Such a change is called an edge. It is important to detect edges in images because they often mark locations at which object properties change. These can include changes in illumination along a surface due to a shadow boundary, or a material (pigment) change, or a change in depth as when one object ends and another begins. The computational problem of finding intensity edges in images is called edge detection. We could look for positions at which DI(x) has a large negative or positive value. Large positive values indicate an edge that goes from low to high intensity, and large negative values indicate an edge that goes from high to low intensity. Example Suppose the image consists of a single (slightly sloped) edge:

http://ieeexplore.ieee.org/iel5/5/31307/01456462.pdf

Linear systems

Ad hoc wireless networks enable new and exciting applications, but also pose significant technical challenges. In this article we give a brief overview of ad hoc wireless networks and their applications with a particular emphasis on energy constraints. We then discuss advances in the link, multiple access, network, and application protocols for these networks. We show that cross-layer design of these protocols is imperative to meet emerging application requirements, particularly when energy is a limited resource.

Design challenges for energy-constrained ad hoc wireless networks

We describe a new orthogonal frequency division multiplexing (OFDM) scheme, named pulsed-OFDM, for ultra wideband (UWB) communications. Pulsed-OFDM modulation uses pulsed sinusoids instead of continuous sinusoids to send information in parallel over different sub-carriers. Pulsating OFDM symbols spreads the spectrum of the modulated signals in the frequency domain leading to a spreading gain equal to the inverse of the duty cycle of the pulsed sub-carriers. The spreading gain provided by this system leads to an enhanced performance in multipath fading environments. We also show that at the receiver part of the multipath diversity can be exploited by pulsed-OFDM system leading to a low complexity and low power consumption transceiver structure. Easy implementation and frequency spreading of pulsed-OFDM modulation make it a proper modulation for UWB communications where the ratio of bandwidth to the data rate is large but power spectral density is limited. We design a low complexity and low power consumption pulsed-OFDM system for the IEEE 802.15.3a wireless personal area networks and compare it with the normal OFDM system has been proposed for this standard. We also provide realistic simulation results for the measured indoor propagation channels provided by the IEEE 802.15.3a standard to demonstrate the advantages of the pulsed OFDM modulation for UWB communications.

Pulsed OFDM modulation for ultra wideband communications

Polar codes are the first provable capacity-achieving forward error correction (FEC) codes. In general polar codes can be decoded via either successive cancellation (SC) or belief propagation (BP) decoding algorithm. However, to date practical applications of polar codes have been hindered by the long decoding latency and limited error-correcting performance problems. In this paper, based on our recent proposed early stopping criteria for the BP algorithm, we propose a hybrid BP-SC decoding scheme to improve the decoding performance of polar codes with relatively short latency. Simulation results show that, for (1024, 512) polar codes the proposed approach leads to at least 0.2dB gain over the BP algorithm with the same maximum number of iterations for the entire SNR region, and also achieves 0.2dB decoding gain over the BP algorithm with the same worst-case latency in the high SNR region. Besides, compared to the SC algorithm, the proposed scheme leads to 0.2dB gain in the medium SNR region with much less average decoding latency. In addition, we also propose the low-complexity unified hardware architecture for the hybrid decoding scheme, which is able to implement SC and BP algorithms using same hardware.

Algorithm and architecture for hybrid decoding of polar codes

The high speed implementation of a DFE (decision feedback equalizer) requires reformulation of the DFE into an array of comparators and a multiplexer loop. The throughput of the DFE is limited by the speed of the multiplexer loop. This paper proposes a novel look-ahead computation approach to pipeline multiplexer loops. The proposed technique is demonstrated and applied to design multiplexer loop based DFEs with throughput in the range of 3.125-10 Gbps.

Pipelining of parallel multiplexer loops and decision feedback equalizers

An n-level look-ahead network converts input values to intermediate values that are provided to a plurality of multiplexers arranged to form a pipelined multiplexer loop. The first stage of the multiplexer loop consists of a single multiplexer. The second stage consists of at least two multiplexers. Communication links couple the output ports of the second stage multiplexers to the input ports of the first stage multiplexer. A first feedback loop electrically couples the output port of the first stage multiplexer to the control port of the first stage multiplexer. This first feedback loop has a first delay device having a first delay time. A second feedback loop couples the output port of the first stage multiplexer to the control ports of the second stage multiplexers. This second feedback loop includes the first delay device and a second delay device having a second delay time.

Pipelining of multiplexer loops in a digital circuit

This paper presents a low-power bit-serial Viterbi decoder chip with the coding rate r=1/3 and the constraint length K=9 (256 states). This chip has been implemented using 0.5 /spl mu/m three-layer metal CMOS technology and is targeted for high speed convolutional decoding for next generation wireless applications such as wide-band CDMA mobile systems and wireless ATM LANs. The chip is expected to operate at 20 Mbps under 3.3 V and at 2 Mbps under 1.8 V. The add-compare-select (ACS) units have been designed using bit-serial arithmetic, which has made it feasible to execute 256 ACS operations in parallel. For trace-back operations, we have developed a novel power-efficient trace-back scheme and an application-specific memory, which was designed considering that 256 bits should be written simultaneously for write operations but only one bit needs to be accessed for read operations. We have estimated that the chip dissipates only 10 mW at 2 Mbps operation under 1.8 V.

Keshab K. Parhi

Papers

Pulsed OFDM modulation for ultra wideband communications

Algorithm and architecture for hybrid decoding of polar codes

Pipelining of parallel multiplexer loops and decision feedback equalizers

Pipelining of multiplexer loops in a digital circuit

Low-power bit-serial Viterbi decoder for next generation wide-band CDMA systems