다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Information Theory and Reliable Communication

Random number generators in digital information systems make use of physical entropy sources such as electronic and photonic noise to add unpredictability to deterministically generated pseudo-random sequences1,2. However, there is a large gap between the generation rates achieved with existing physical sources and the high data rates of many computation and communication systems; this is a fundamental weakness of these systems. Here we show that good quality random bit sequences can be generated at very fast bit rates using physical chaos in semiconductor lasers. Streams of bits that pass standard statistical tests for randomness have been generated at rates of up to 1.7 Gbps by sampling the fluctuating optical output of two chaotic lasers. This rate is an order of magnitude faster than that of previously reported devices for physical random bit generators with verified randomness. This means that the performance of random number generators can be greatly improved by using chaotic laser devices as physical entropy sources. Random-number generators are important in digital information systems. However, the speed at which current sources operate is much slower than the typical data rates used in communication and computing. Chaos in semiconductor lasers might help to bridge the gap.

Fast physical random bit generation with chaotic semiconductor lasers

The power consumed by a circuit varies according to the activity of its individual transistors and other components As a result, measurements of the power used by actual computers or microchips contain information about the operations being performed and the data being processed Cryptographic designs have traditionally assumed that secrets are manipulated in environments that expose no information beyond the specified inputs and outputs This paper examines how information leaked through power consumption and other side channels can be analyzed to extract secret keys from a wide range of devices The attacks are practical, non-invasive, and highly effective—even against complex and noisy systems where cryptographic computations account for only a small fraction of the overall power consumption We also introduce approaches for preventing DPA attacks and for building cryptosystems that remain secure even when implemented in hardware that leaks

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Introduction to differential power analysis

Analogue IC Design: the Current Mode Approach

A new methodology for yield optimization of integrated circuits is presented. We propose a dc external control scheme which performs on-line estimation of the active device model parameters and proper correction of the bias point. Design of a 2.5 Gbit/s front-end amplifier has been performed, and a strong yield improvement has been found. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 134–137, 2001.

Bias correction and yield optimization of MMICs with external digital control

An E-band Variable Gain Amplifier with 24 dB-control range and 80 to 100 GHz 1 dB bandwidth in SiGe BiCMOS technology

In this paper a novel linear transconductor topology is proposed, where class-AB behavior based on adaptive biasing is exploited to improve the linear range. The adaptive biasing circuit is based on the Winner-Take-All topology already used for class-AB OTAs, and optimized to improve the linearity, and the proposed transconductor features a gain control input for tunability. The transconductor provides a gain of 43 μS while consuming 70 μW. The linear range (1% variation of the dc transconductance gain) is 470 mVpp, about 4.5 times larger than for the corresponding class-A cell. Total harmonic distortion is improved by about 15 dB, and good results in terms of linearity and noise are reported with respect to the state-of-the-art. Simulations of a Gm-C biquad filter based on the proposed transconductor are also reported to validate the design.

A class-AB linear transconductor with enhanced linearity

A novel topology of lossy equalizer with impedance transformation and stabilization capability is presented, which allows the design of broadband very high-linearity and high-power amplifiers. Design equations are presented and used to design a 1-2.4 GHz 60W composite amplifier exploiting push-pull configuration.

Design of broad-band power amplifiers by means of an impedance transforming lossy equalizer

A criterion to check the conditional stability of linear active two-port networks comprising more than one active device and terminated with complex impedances is presented. The proposed necessary and sufficient condition allows the guarantee of the stability in circular regions around the nominal terminations, thus providing circuit robustness with respect to load variations. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 360–360, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mmce10033

Alessandro Trifiletti

Papers

Bias correction and yield optimization of MMICs with external digital control

An E-band Variable Gain Amplifier with 24 dB-control range and 80 to 100 GHz 1 dB bandwidth in SiGe BiCMOS technology

A class-AB linear transconductor with enhanced linearity

Design of broad-band power amplifiers by means of an impedance transforming lossy equalizer

Design of stable microwave multidevice circuits with complex termination impedances