Quantum random number generator
Pooser, Raphael C.
2016-05-10
A quantum random number generator (QRNG) and a photon generator for a QRNG are provided. The photon generator may be operated in a spontaneous mode below a lasing threshold to emit photons. Photons emitted from the photon generator may have at least one random characteristic, which may be monitored by the QRNG to generate a random number. In one embodiment, the photon generator may include a photon emitter and an amplifier coupled to the photon emitter. The amplifier may enable the photon generator to be used in the QRNG without introducing significant bias in the random number and may enable multiplexing of multiple random numbers. The amplifier may also desensitize the photon generator to fluctuations in power supplied thereto while operating in the spontaneous mode. In one embodiment, the photon emitter and amplifier may be a tapered diode amplifier.
Quantum random number generation
Ma, Xiongfeng; Yuan, Xiao; Cao, Zhu; Zhang, Zhen; Qi, Bing
2016-06-28
Quantum physics can be exploited to generate true random numbers, which play important roles in many applications, especially in cryptography. Genuine randomness from the measurement of a quantum system reveals the inherent nature of quantumness -- coherence, an important feature that differentiates quantum mechanics from classical physics. The generation of genuine randomness is generally considered impossible with only classical means. Based on the degree of trustworthiness on devices, quantum random number generators (QRNGs) can be grouped into three categories. The first category, practical QRNG, is built on fully trusted and calibrated devices and typically can generate randomness at a high speed by properly modeling the devices. The second category is self-testing QRNG, where verifiable randomness can be generated without trusting the actual implementation. The third category, semi-self-testing QRNG, is an intermediate category which provides a tradeoff between the trustworthiness on the device and the random number generation speed.
Quantum random number generation
Ma, Xiongfeng; Yuan, Xiao; Cao, Zhu; ...
2016-06-28
Quantum physics can be exploited to generate true random numbers, which play important roles in many applications, especially in cryptography. Genuine randomness from the measurement of a quantum system reveals the inherent nature of quantumness -- coherence, an important feature that differentiates quantum mechanics from classical physics. The generation of genuine randomness is generally considered impossible with only classical means. Based on the degree of trustworthiness on devices, quantum random number generators (QRNGs) can be grouped into three categories. The first category, practical QRNG, is built on fully trusted and calibrated devices and typically can generate randomness at a highmore » speed by properly modeling the devices. The second category is self-testing QRNG, where verifiable randomness can be generated without trusting the actual implementation. The third category, semi-self-testing QRNG, is an intermediate category which provides a tradeoff between the trustworthiness on the device and the random number generation speed.« less
Quantum random number generation
NASA Astrophysics Data System (ADS)
Ma, Xiongfeng; Yuan, Xiao; Cao, Zhu; Qi, Bing; Zhang, Zhen
2016-06-01
Quantum physics can be exploited to generate true random numbers, which have important roles in many applications, especially in cryptography. Genuine randomness from the measurement of a quantum system reveals the inherent nature of quantumness—coherence, an important feature that differentiates quantum mechanics from classical physics. The generation of genuine randomness is generally considered impossible with only classical means. On the basis of the degree of trustworthiness on devices, quantum random number generators (QRNGs) can be grouped into three categories. The first category, practical QRNG, is built on fully trusted and calibrated devices and typically can generate randomness at a high speed by properly modelling the devices. The second category is self-testing QRNG, in which verifiable randomness can be generated without trusting the actual implementation. The third category, semi-self-testing QRNG, is an intermediate category that provides a tradeoff between the trustworthiness on the device and the random number generation speed.
Quantum random number generators
NASA Astrophysics Data System (ADS)
Herrero-Collantes, Miguel; Garcia-Escartin, Juan Carlos
2017-01-01
Random numbers are a fundamental resource in science and engineering with important applications in simulation and cryptography. The inherent randomness at the core of quantum mechanics makes quantum systems a perfect source of entropy. Quantum random number generation is one of the most mature quantum technologies with many alternative generation methods. This review discusses the different technologies in quantum random number generation from the early devices based on radioactive decay to the multiple ways to use the quantum states of light to gather entropy from a quantum origin. Randomness extraction and amplification and the notable possibility of generating trusted random numbers even with untrusted hardware using device-independent generation protocols are also discussed.
[Intel random number generator-based true random number generator].
Huang, Feng; Shen, Hong
2004-09-01
To establish a true random number generator on the basis of certain Intel chips. The random numbers were acquired by programming using Microsoft Visual C++ 6.0 via register reading from the random number generator (RNG) unit of an Intel 815 chipset-based computer with Intel Security Driver (ISD). We tested the generator with 500 random numbers in NIST FIPS 140-1 and X(2) R-Squared test, and the result showed that the random number it generated satisfied the demand of independence and uniform distribution. We also compared the random numbers generated by Intel RNG-based true random number generator and those from the random number table statistically, by using the same amount of 7500 random numbers in the same value domain, which showed that the SD, SE and CV of Intel RNG-based random number generator were less than those of the random number table. The result of u test of two CVs revealed no significant difference between the two methods. Intel RNG-based random number generator can produce high-quality random numbers with good independence and uniform distribution, and solves some problems with random number table in acquisition of the random numbers.
Random number generation and creativity.
Bains, William
2008-01-01
A previous paper suggested that humans can generate genuinely random numbers. I tested this hypothesis by repeating the experiment with a larger number of highly numerate subjects, asking them to call out a sequence of digits selected from 0 through 9. The resulting sequences were substantially non-random, with an excess of sequential pairs of numbers and a deficit of repeats of the same number, in line with previous literature. However, the previous literature suggests that humans generate random numbers with substantial conscious effort, and distractions which reduce that effort reduce the randomness of the numbers. I reduced my subjects' concentration by asking them to call out in another language, and with alcohol - neither affected the randomness of their responses. This suggests that the ability to generate random numbers is a 'basic' function of the human mind, even if those numbers are not mathematically 'random'. I hypothesise that there is a 'creativity' mechanism, while not truly random, provides novelty as part of the mind's defence against closed programming loops, and that testing for the effects seen here in people more or less familiar with numbers or with spontaneous creativity could identify more features of this process. It is possible that training to perform better at simple random generation tasks could help to increase creativity, through training people to reduce the conscious mind's suppression of the 'spontaneous', creative response to new questions.
Thermodynamics of random number generation
NASA Astrophysics Data System (ADS)
Aghamohammadi, Cina; Crutchfield, James P.
2017-06-01
We analyze the thermodynamic costs of the three main approaches to generating random numbers via the recently introduced Information Processing Second Law. Given access to a specified source of randomness, a random number generator (RNG) produces samples from a desired target probability distribution. This differs from pseudorandom number generators (PRNGs) that use wholly deterministic algorithms and from true random number generators (TRNGs) in which the randomness source is a physical system. For each class, we analyze the thermodynamics of generators based on algorithms implemented as finite-state machines, as these allow for direct bounds on the required physical resources. This establishes bounds on heat dissipation and work consumption during the operation of three main classes of RNG algorithms—including those of von Neumann, Knuth, and Yao and Roche and Hoshi—and for PRNG methods. We introduce a general TRNG and determine its thermodynamic costs exactly for arbitrary target distributions. The results highlight the significant differences between the three main approaches to random number generation: One is work producing, one is work consuming, and the other is potentially dissipation neutral. Notably, TRNGs can both generate random numbers and convert thermal energy to stored work. These thermodynamic costs on information creation complement Landauer's limit on the irreducible costs of information destruction.
The MIXMAX random number generator
NASA Astrophysics Data System (ADS)
Savvidy, Konstantin G.
2015-11-01
In this paper, we study the randomness properties of unimodular matrix random number generators. Under well-known conditions, these discrete-time dynamical systems have the highly desirable K-mixing properties which guarantee high quality random numbers. It is found that some widely used random number generators have poor Kolmogorov entropy and consequently fail in empirical tests of randomness. These tests show that the lowest acceptable value of the Kolmogorov entropy is around 50. Next, we provide a solution to the problem of determining the maximal period of unimodular matrix generators of pseudo-random numbers. We formulate the necessary and sufficient condition to attain the maximum period and present a family of specific generators in the MIXMAX family with superior performance and excellent statistical properties. Finally, we construct three efficient algorithms for operations with the MIXMAX matrix which is a multi-dimensional generalization of the famous cat-map. First, allowing to compute the multiplication by the MIXMAX matrix with O(N) operations. Second, to recursively compute its characteristic polynomial with O(N2) operations, and third, to apply skips of large number of steps S to the sequence in O(N2 log(S)) operations.
High speed optical quantum random number generation.
Fürst, Martin; Weier, Henning; Nauerth, Sebastian; Marangon, Davide G; Kurtsiefer, Christian; Weinfurter, Harald
2010-06-07
We present a fully integrated, ready-for-use quantum random number generator (QRNG) whose stochastic model is based on the randomness of detecting single photons in attenuated light. We show that often annoying deadtime effects associated with photomultiplier tubes (PMT) can be utilized to avoid postprocessing for bias or correlations. The random numbers directly delivered to a PC, generated at a rate of up to 50 Mbit/s, clearly pass all tests relevant for (physical) random number generators.
Self-correcting random number generator
Humble, Travis S.; Pooser, Raphael C.
2016-09-06
A system and method for generating random numbers. The system may include a random number generator (RNG), such as a quantum random number generator (QRNG) configured to self-correct or adapt in order to substantially achieve randomness from the output of the RNG. By adapting, the RNG may generate a random number that may be considered random regardless of whether the random number itself is tested as such. As an example, the RNG may include components to monitor one or more characteristics of the RNG during operation, and may use the monitored characteristics as a basis for adapting, or self-correcting, to provide a random number according to one or more performance criteria.
Generation of pseudo-random numbers
NASA Technical Reports Server (NTRS)
Howell, L. W.; Rheinfurth, M. H.
1982-01-01
Practical methods for generating acceptable random numbers from a variety of probability distributions which are frequently encountered in engineering applications are described. The speed, accuracy, and guarantee of statistical randomness of the various methods are discussed.
Ultra-fast Quantum Random Number Generator
NASA Astrophysics Data System (ADS)
Yicheng, Shi
We describe a series of Randomness Extractors for removing bias and residual correlations in random numbers generated from measurements on noisy physical systems. The structures of the randomness extractors are based on Linear Feedback Shift Registers (LFSR). This leads to a significant simplification in the implementation of randomness extractors.
All-optical fast random number generator.
Li, Pu; Wang, Yun-Cai; Zhang, Jian-Zhong
2010-09-13
We propose a scheme of all-optical random number generator (RNG), which consists of an ultra-wide bandwidth (UWB) chaotic laser, an all-optical sampler and an all-optical comparator. Free from the electric-device bandwidth, it can generate 10Gbit/s random numbers in our simulation. The high-speed bit sequences can pass standard statistical tests for randomness after all-optical exclusive-or (XOR) operation.
Self-Testing Quantum Random Number Generator
NASA Astrophysics Data System (ADS)
Lunghi, Tommaso; Brask, Jonatan Bohr; Lim, Charles Ci Wen; Lavigne, Quentin; Bowles, Joseph; Martin, Anthony; Zbinden, Hugo; Brunner, Nicolas
2015-04-01
The generation of random numbers is a task of paramount importance in modern science. A central problem for both classical and quantum randomness generation is to estimate the entropy of the data generated by a given device. Here we present a protocol for self-testing quantum random number generation, in which the user can monitor the entropy in real time. Based on a few general assumptions, our protocol guarantees continuous generation of high quality randomness, without the need for a detailed characterization of the devices. Using a fully optical setup, we implement our protocol and illustrate its self-testing capacity. Our work thus provides a practical approach to quantum randomness generation in a scenario of trusted but error-prone devices.
Source-Independent Quantum Random Number Generation
NASA Astrophysics Data System (ADS)
Cao, Zhu; Zhou, Hongyi; Yuan, Xiao; Ma, Xiongfeng
2016-01-01
Quantum random number generators can provide genuine randomness by appealing to the fundamental principles of quantum mechanics. In general, a physical generator contains two parts—a randomness source and its readout. The source is essential to the quality of the resulting random numbers; hence, it needs to be carefully calibrated and modeled to achieve information-theoretical provable randomness. However, in practice, the source is a complicated physical system, such as a light source or an atomic ensemble, and any deviations in the real-life implementation from the theoretical model may affect the randomness of the output. To close this gap, we propose a source-independent scheme for quantum random number generation in which output randomness can be certified, even when the source is uncharacterized and untrusted. In our randomness analysis, we make no assumptions about the dimension of the source. For instance, multiphoton emissions are allowed in optical implementations. Our analysis takes into account the finite-key effect with the composable security definition. In the limit of large data size, the length of the input random seed is exponentially small compared to that of the output random bit. In addition, by modifying a quantum key distribution system, we experimentally demonstrate our scheme and achieve a randomness generation rate of over 5 ×103 bit /s .
Truly random number generation: an example
NASA Astrophysics Data System (ADS)
Frauchiger, Daniela; Renner, Renato
2013-10-01
Randomness is crucial for a variety of applications, ranging from gambling to computer simulations, and from cryptography to statistics. However, many of the currently used methods for generating randomness do not meet the criteria that are necessary for these applications to work properly and safely. A common problem is that a sequence of numbers may look random but nevertheless not be truly random. In fact, the sequence may pass all standard statistical tests and yet be perfectly predictable. This renders it useless for many applications. For example, in cryptography, the predictability of a "andomly" chosen password is obviously undesirable. Here, we review a recently developed approach to generating true | and hence unpredictable | randomness.
Random Number Generation for High Performance Computing
2015-01-01
SECURITY CLASSIFICATION OF: The primary objectives of the Phase II of the project are: (a) implement the context-aware parallel random number...Report Title The primary objectives of the Phase II of the project are: (a) implement the context-aware parallel random number generator (CPRNG...standard Unix/Linux systems, and a parallel RNG based on cryptographic operations from the family of generators proposed by D.E. Shaw Group [12], and a
Analysis of Additive Random Number Generators.
1977-03-01
linear congruential generators yn*\\* ayn+bmo,iPa- The simplest example of a sequence satisfying (1.1) with *> I is the Fibonacci sequence with p - 2...However, the Fibonacci sequence is not a suitable random number generator because successive triples are very poorly distributed in three...number generator should have small discrepancy. Definition 2.1 can be extended naturally to define discrepancy for sequences of points yn lying in
Quantum random number generator using photon-number path entanglement
NASA Astrophysics Data System (ADS)
Kwon, Osung; Cho, Young-Wook; Kim, Yoon-Ho
2010-08-01
We report an experimental implementation of quantum random number generator based on the photon-number-path entangled state. The photon-number-path entangled state is prepared by means of two-photon Hong-Ou-Mandel quantum interference at a beam splitter. The randomness in our scheme is of truly quantum mechanical origin as it comes from the projection measurement of the entangled two-photon state. The generated bit sequences satisfy the standard randomness test.
Statistical Analysis of Random Number Generators
NASA Astrophysics Data System (ADS)
Accardi, Luigi; Gäbler, Markus
2011-01-01
In many applications, for example cryptography and Monte Carlo simulation, there is need for random numbers. Any procedure, algorithm or device which is intended to produce such is called a random number generator (RNG). What makes a good RNG? This paper gives an overview on empirical testing of the statistical properties of the sequences produced by RNGs and special software packages designed for that purpose. We also present the results of applying a particular test suite--TestU01-- to a family of RNGs currently being developed at the Centro Interdipartimentale Vito Volterra (CIVV), Roma, Italy.
Random Number Generation with Cosmic Photons.
Wu, Cheng; Bai, Bing; Liu, Yang; Zhang, Xiaoming; Yang, Meng; Cao, Yuan; Wang, Jianfeng; Zhang, Shaohua; Zhou, Hongyan; Shi, Xiheng; Ma, Xiongfeng; Ren, Ji-Gang; Zhang, Jun; Peng, Cheng-Zhi; Fan, Jingyun; Zhang, Qiang; Pan, Jian-Wei
2017-04-07
Random numbers are indispensable for a variety of applications ranging from testing physics foundations to information encryption. In particular, nonlocality test provide strong evidence for our current understanding of nature-quantum mechanics. All the random number generators (RNGs) used for the existing tests are constructed locally, making the test results vulnerable to the freedom-of-choice loophole. We report an experimental realization of RNGs based on the arrival time of cosmic photons. The measurement outcomes (raw data) pass the standard NIST statistical test suite. We present a realistic design to employ these RNGs in a Bell test experiment, which addresses the freedom-of-choice loophole.
Random Number Generation with Cosmic Photons
NASA Astrophysics Data System (ADS)
Wu, Cheng; Bai, Bing; Liu, Yang; Zhang, Xiaoming; Yang, Meng; Cao, Yuan; Wang, Jianfeng; Zhang, Shaohua; Zhou, Hongyan; Shi, Xiheng; Ma, Xiongfeng; Ren, Ji-Gang; Zhang, Jun; Peng, Cheng-Zhi; Fan, Jingyun; Zhang, Qiang; Pan, Jian-Wei
2017-04-01
Random numbers are indispensable for a variety of applications ranging from testing physics foundations to information encryption. In particular, nonlocality test provide strong evidence for our current understanding of nature—quantum mechanics. All the random number generators (RNGs) used for the existing tests are constructed locally, making the test results vulnerable to the freedom-of-choice loophole. We report an experimental realization of RNGs based on the arrival time of cosmic photons. The measurement outcomes (raw data) pass the standard NIST statistical test suite. We present a realistic design to employ these RNGs in a Bell test experiment, which addresses the freedom-of-choice loophole.
The RANDOM computer program: A linear congruential random number generator
NASA Technical Reports Server (NTRS)
Miles, R. F., Jr.
1986-01-01
The RANDOM Computer Program is a FORTRAN program for generating random number sequences and testing linear congruential random number generators (LCGs). The linear congruential form of random number generator is discussed, and the selection of parameters of an LCG for a microcomputer described. This document describes the following: (1) The RANDOM Computer Program; (2) RANDOM.MOD, the computer code needed to implement an LCG in a FORTRAN program; and (3) The RANCYCLE and the ARITH Computer Programs that provide computational assistance in the selection of parameters for an LCG. The RANDOM, RANCYCLE, and ARITH Computer Programs are written in Microsoft FORTRAN for the IBM PC microcomputer and its compatibles. With only minor modifications, the RANDOM Computer Program and its LCG can be run on most micromputers or mainframe computers.
Operational conditions for random-number generation
NASA Astrophysics Data System (ADS)
Compagner, A.
1995-11-01
Ensemble theory is used to describe arbitrary sequences of integers, whether formed by the decimals of π or produced by a roulette or by any other means. Correlation coefficients of any range and order are defined as Fourier transforms of the ensemble weights. Competing definitions of random sequences are considered. Special attention is given to sequences of random numbers needed for Monte Carlo calculations. Different recipes for those sequences lead to correlations that vary in range and order, but the total amount of correlation is the same for all sequences of a given length (without internal periodicities). For maximum-length sequences produced by linear algorithms, most correlation coefficients are zero, but the remaining ones are of absolute value 1. In well-tempered sequences, these complete correlations are of high order or of very long range. General conditions to be obeyed by random-number generators are discussed and a qualitative method for comparing different recipes is given.
Random number generation from spontaneous Raman scattering
NASA Astrophysics Data System (ADS)
Collins, M. J.; Clark, A. S.; Xiong, C.; Mägi, E.; Steel, M. J.; Eggleton, B. J.
2015-10-01
We investigate the generation of random numbers via the quantum process of spontaneous Raman scattering. Spontaneous Raman photons are produced by illuminating a highly nonlinear chalcogenide glass ( As 2 S 3 ) fiber with a CW laser at a power well below the stimulated Raman threshold. Single Raman photons are collected and separated into two discrete wavelength detuning bins of equal scattering probability. The sequence of photon detection clicks is converted into a random bit stream. Postprocessing is applied to remove detector bias, resulting in a final bit rate of ˜650 kb/s. The collected random bit-sequences pass the NIST statistical test suite for one hundred 1 Mb samples, with the significance level set to α = 0.01 . The fiber is stable, robust and the high nonlinearity (compared to silica) allows for a short fiber length and low pump power favourable for real world application.
Long period pseudo random number sequence generator
NASA Technical Reports Server (NTRS)
Wang, Charles C. (Inventor)
1989-01-01
A circuit for generating a sequence of pseudo random numbers, (A sub K). There is an exponentiator in GF(2 sup m) for the normal basis representation of elements in a finite field GF(2 sup m) each represented by m binary digits and having two inputs and an output from which the sequence (A sub K). Of pseudo random numbers is taken. One of the two inputs is connected to receive the outputs (E sub K) of maximal length shift register of n stages. There is a switch having a pair of inputs and an output. The switch outputs is connected to the other of the two inputs of the exponentiator. One of the switch inputs is connected for initially receiving a primitive element (A sub O) in GF(2 sup m). Finally, there is a delay circuit having an input and an output. The delay circuit output is connected to the other of the switch inputs and the delay circuit input is connected to the output of the exponentiator. Whereby after the exponentiator initially receives the primitive element (A sub O) in GF(2 sup m) through the switch, the switch can be switched to cause the exponentiator to receive as its input a delayed output A(K-1) from the exponentiator thereby generating (A sub K) continuously at the output of the exponentiator. The exponentiator in GF(2 sup m) is novel and comprises a cyclic-shift circuit; a Massey-Omura multiplier; and, a control logic circuit all operably connected together to perform the function U(sub i) = 92(sup i) (for n(sub i) = 1 or 1 (for n(subi) = 0).
A Pseudo-Random Number Generator Based on Normal Numbers
Bailey, David H.
2004-12-31
In a recent paper, Richard Crandall and the present author established that each of a certain class of explicitly given real constants, uncountably infinite in number, is b-normal, for an integer that appears in the formula defining the constant. A b-normal constant is one where every string of m digits appears in the base-b expansion of the constant with limiting frequency b{sup -m}. This paper shows how this result can be used to fashion an efficient and effective pseudo-random number generator, which generates successive strings of binary digits from one of the constants in this class. The resulting generator, which tests slightly faster than a conventional linear congruential generator, avoids difficulties with large power-of-two data access strides that may occur when using conventional generators. It is also well suited for parallel processing--each processor can quickly and independently compute its starting value, with the collective sequence generated by all processors being the same as that generated by a single processor.
An integrable low-cost hardware random number generator
NASA Astrophysics Data System (ADS)
Ranasinghe, Damith C.; Lim, Daihyun; Devadas, Srinivas; Jamali, Behnam; Zhu, Zheng; Cole, Peter H.
2005-02-01
A hardware random number generator is different from a pseudo-random number generator; a pseudo-random number generator approximates the assumed behavior of a real hardware random number generator. Simple pseudo random number generators suffices for most applications, however for demanding situations such as the generation of cryptographic keys, requires an efficient and a cost effective source of random numbers. Arbiter-based Physical Unclonable Functions (PUFs) proposed for physical authentication of ICs exploits statistical delay variation of wires and transistors across integrated circuits, as a result of process variations, to build a secret key unique to each IC. Experimental results and theoretical studies show that a sufficient amount of variation exits across IC"s. This variation enables each IC to be identified securely. It is possible to exploit the unreliability of these PUF responses to build a physical random number generator. There exists measurement noise, which comes from the instability of an arbiter when it is in a racing condition. There exist challenges whose responses are unpredictable. Without environmental variations, the responses of these challenges are random in repeated measurements. Compared to other physical random number generators, the PUF-based random number generators can be a compact and a low-power solution since the generator need only be turned on when required. A 64-stage PUF circuit costs less than 1000 gates and the circuit can be implemented using a standard IC manufacturing processes. In this paper we have presented a fast and an efficient random number generator, and analysed the quality of random numbers produced using an array of tests used by the National Institute of Standards and Technology to evaluate the randomness of random number generators designed for cryptographic applications.
Quantum random number generator based on twin beams.
Zhang, Qiang; Deng, Xiaowei; Tian, Caixing; Su, Xiaolong
2017-03-01
We produce two strings of quantum random numbers simultaneously from the intensity fluctuations of the twin beams generated by a nondegenerate optical parametric oscillator. Two strings of quantum random numbers with bit rates up to 60 Mb/s are extracted simultaneously with a suitable post-processing algorithm. By post-selecting the identical data from two raw sequences and using a suitable hash function, we also extract two strings of identical quantum random numbers. The obtained random numbers pass all NIST randomness tests. The presented scheme shows the feasibility of generating quantum random numbers from the intensity of a macroscopic optical field.
Towards a high-speed quantum random number generator
NASA Astrophysics Data System (ADS)
Stucki, Damien; Burri, Samuel; Charbon, Edoardo; Chunnilall, Christopher; Meneghetti, Alessio; Regazzoni, Francesco
2013-10-01
Randomness is of fundamental importance in various fields, such as cryptography, numerical simulations, or the gaming industry. Quantum physics, which is fundamentally probabilistic, is the best option for a physical random number generator. In this article, we will present the work carried out in various projects in the context of the development of a commercial and certified high speed random number generator.
Generation of physical random numbers by using homodyne detection
NASA Astrophysics Data System (ADS)
Hirakawa, Kodai; Oya, Shota; Oguri, Yusuke; Ichikawa, Tsubasa; Eto, Yujiro; Hirano, Takuya; Tsurumaru, Toyohiro
2016-10-01
Physical random numbers generated by quantum measurements are, in principle, impossible to predict. We have demonstrated the generation of physical random numbers by using a high-speed balanced photodetector to measure the quadrature amplitudes of vacuum states. Using this method, random numbers were generated at 500 Mbps, which is more than one order of magnitude faster than previously [Gabriel et al:, Nature Photonics 4, 711-715 (2010)]. The Crush test battery of the TestU01 suite consists of 31 tests in 144 variations, and we used them to statistically analyze these numbers. The generated random numbers passed 14 of the 31 tests. To improve the randomness, we performed a hash operation, in which each random number was multiplied by a random Toeplitz matrix; the resulting numbers passed all of the tests in the TestU01 Crush battery.
Quantum random number generation for loophole-free Bell tests
NASA Astrophysics Data System (ADS)
Mitchell, Morgan; Abellan, Carlos; Amaya, Waldimar
2015-05-01
We describe the generation of quantum random numbers at multi-Gbps rates, combined with real-time randomness extraction, to give very high purity random numbers based on quantum events at most tens of ns in the past. The system satisfies the stringent requirements of quantum non-locality tests that aim to close the timing loophole. We describe the generation mechanism using spontaneous-emission-driven phase diffusion in a semiconductor laser, digitization, and extraction by parity calculation using multi-GHz logic chips. We pay special attention to experimental proof of the quality of the random numbers and analysis of the randomness extraction. In contrast to widely-used models of randomness generators in the computer science literature, we argue that randomness generation by spontaneous emission can be extracted from a single source.
Quantum Random Number Generation on a Mobile Phone
NASA Astrophysics Data System (ADS)
Sanguinetti, Bruno; Martin, Anthony; Zbinden, Hugo; Gisin, Nicolas
2014-07-01
Quantum random number generators (QRNGs) can significantly improve the security of cryptographic protocols by ensuring that generated keys cannot be predicted. However, the cost, size, and power requirements of current Quantum random number generators have prevented them from becoming widespread. In the meantime, the quality of the cameras integrated in mobile telephones has improved significantly so that now they are sensitive to light at the few-photon level. We demonstrate how these can be used to generate random numbers of a quantum origin.
RNGAVXLIB: Program library for random number generation, AVX realization
NASA Astrophysics Data System (ADS)
Guskova, M. S.; Barash, L. Yu.; Shchur, L. N.
2016-03-01
We present the random number generator (RNG) library RNGAVXLIB, which contains fast AVX realizations of a number of modern random number generators, and also the abilities to jump ahead inside a RNG sequence and to initialize up to 1019 independent random number streams with block splitting method. Fast AVX implementations produce exactly the same output sequences as the original algorithms. Usage of AVX vectorization allows to substantially improve performance of the generators. The new realizations are up to 2 times faster than the SSE realizations implemented in the previous version of the library (Barash and Shchur, 2013), and up to 40 times faster compared to the original algorithms written in ANSI C.
Ternary jitter-based true random number generator
NASA Astrophysics Data System (ADS)
Latypov, Rustam; Stolov, Evgeni
2017-01-01
In this paper a novel family of generators producing true uniform random numbers in ternary logic is presented. The generator consists of a number of identical ternary logic combinational units connected into a ring. All the units are provided to have a random delay time, and this time is supposed to be distributed in accordance with an exponential distribution. All delays are supposed to be independent events. The theory of the generator is based on Erlang equations. The generator can be used for test production in various systems. Features of multidimensional random vectors, produced by the generator, are discussed.
Pseudo-random number generator for the Sigma 5 computer
NASA Technical Reports Server (NTRS)
Carroll, S. N.
1983-01-01
A technique is presented for developing a pseudo-random number generator based on the linear congruential form. The two numbers used for the generator are a prime number and a corresponding primitive root, where the prime is the largest prime number that can be accurately represented on a particular computer. The primitive root is selected by applying Marsaglia's lattice test. The technique presented was applied to write a random number program for the Sigma 5 computer. The new program, named S:RANDOM1, is judged to be superior to the older program named S:RANDOM. For applications requiring several independent random number generators, a table is included showing several acceptable primitive roots. The technique and programs described can be applied to any computer having word length different from that of the Sigma 5.
Quantum Random Number Generation Using a Quanta Image Sensor.
Amri, Emna; Felk, Yacine; Stucki, Damien; Ma, Jiaju; Fossum, Eric R
2016-06-29
A new quantum random number generation method is proposed. The method is based on the randomness of the photon emission process and the single photon counting capability of the Quanta Image Sensor (QIS). It has the potential to generate high-quality random numbers with remarkable data output rate. In this paper, the principle of photon statistics and theory of entropy are discussed. Sample data were collected with QIS jot device, and its randomness quality was analyzed. The randomness assessment method and results are discussed.
Quantum Random Number Generation Using a Quanta Image Sensor
Amri, Emna; Felk, Yacine; Stucki, Damien; Ma, Jiaju; Fossum, Eric R.
2016-01-01
A new quantum random number generation method is proposed. The method is based on the randomness of the photon emission process and the single photon counting capability of the Quanta Image Sensor (QIS). It has the potential to generate high-quality random numbers with remarkable data output rate. In this paper, the principle of photon statistics and theory of entropy are discussed. Sample data were collected with QIS jot device, and its randomness quality was analyzed. The randomness assessment method and results are discussed. PMID:27367698
The Evolution of Random Number Generation in MUVES
2017-01-01
ARL-TR-7928• JAN 2017 US Army Research Laboratory The Evolution ofRandom Number Generationin MUVES by Joseph C Collins Approved for public release...Laboratory The Evolution ofRandom Number Generationin MUVES by Joseph C Collins Survivability/Lethality Analysis Directorate, ARL Approved for public release...Report The Evolution of Random Number Generation in MUVES Joseph C Collins ARL-TR-7928 Approved for public release; distribution is unlimited. October 2013
Fast quantum-optical random-number generators
NASA Astrophysics Data System (ADS)
Durt, Thomas; Belmonte, Carlos; Lamoureux, Louis-Philippe; Panajotov, Krassimir; Van den Berghe, Frederik; Thienpont, Hugo
2013-02-01
In this paper we study experimentally the properties of three types of quantum -optical random-number generators and characterize them using the available National Institute for Standards and Technology statistical tests, as well as four alternate tests. The generators are characterized by a trade-off between, on one hand, the rate of generation of random bits and, on the other hand, the degree of randomness of the series which they deliver. We describe various techniques aimed at maximizing this rate without diminishing the quality (degree of randomness) of the series generated by it.
A hybrid-type quantum random number generator
NASA Astrophysics Data System (ADS)
Hai-Qiang, Ma; Wu, Zhu; Ke-Jin, Wei; Rui-Xue, Li; Hong-Wei, Liu
2016-05-01
This paper proposes a well-performing hybrid-type truly quantum random number generator based on the time interval between two independent single-photon detection signals, which is practical and intuitive, and generates the initial random number sources from a combination of multiple existing random number sources. A time-to-amplitude converter and multichannel analyzer are used for qualitative analysis to demonstrate that each and every step is random. Furthermore, a carefully designed data acquisition system is used to obtain a high-quality random sequence. Our scheme is simple and proves that the random number bit rate can be dramatically increased to satisfy practical requirements. Project supported by the National Natural Science Foundation of China (Grant Nos. 61178010 and 11374042), the Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), China, and the Fundamental Research Funds for the Central Universities of China (Grant No. bupt2014TS01).
Monte Carlo simulations: Hidden errors from ``good'' random number generators
NASA Astrophysics Data System (ADS)
Ferrenberg, Alan M.; Landau, D. P.; Wong, Y. Joanna
1992-12-01
The Wolff algorithm is now accepted as the best cluster-flipping Monte Carlo algorithm for beating ``critical slowing down.'' We show how this method can yield incorrect answers due to subtle correlations in ``high quality'' random number generators.
Assessment of Human Random Number Generation for Biometric Verification
Jokar, Elham; Mikaili, Mohammad
2012-01-01
Random number generation is one of the human abilities. It is proven that the sequence of random numbers generated by people do not follow full randomness criteria. These numbers produced by brain activity seem to be completely nonstationary. In this paper, we show that there is a distinction between the random numbers generated by different people who provide the discrimination capability, and can be used as a biometric signature. We considered these numbers as a signal, and their complexity for various time-frequency sections was calculated. Then with a proper structure of a support vector machine, we classify the features. The error rate, obtained in this study, shows high discrimination capabilities for this biometric characteristic. PMID:23626943
NASA Astrophysics Data System (ADS)
Miszczak, Jarosław Adam
2013-01-01
The presented package for the Mathematica computing system allows the harnessing of quantum random number generators (QRNG) for investigating the statistical properties of quantum states. The described package implements a number of functions for generating random states. The new version of the package adds the ability to use the on-line quantum random number generator service and implements new functions for retrieving lists of random numbers. Thanks to the introduced improvements, the new version provides faster access to high-quality sources of random numbers and can be used in simulations requiring large amount of random data. New version program summaryProgram title: TRQS Catalogue identifier: AEKA_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKA_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 18 134 No. of bytes in distributed program, including test data, etc.: 2 520 49 Distribution format: tar.gz Programming language: Mathematica, C. Computer: Any supporting Mathematica in version 7 or higher. Operating system: Any platform supporting Mathematica; tested with GNU/Linux (32 and 64 bit). RAM: Case-dependent Supplementary material: Fig. 1 mentioned below can be downloaded. Classification: 4.15. External routines: Quantis software library (http://www.idquantique.com/support/quantis-trng.html) Catalogue identifier of previous version: AEKA_v1_0 Journal reference of previous version: Comput. Phys. Comm. 183(2012)118 Does the new version supersede the previous version?: Yes Nature of problem: Generation of random density matrices and utilization of high-quality random numbers for the purpose of computer simulation. Solution method: Use of a physical quantum random number generator and an on-line service providing access to the source of true random
Social Noise: Generating Random Numbers from Twitter Streams
NASA Astrophysics Data System (ADS)
Fernández, Norberto; Quintas, Fernando; Sánchez, Luis; Arias, Jesús
2015-12-01
Due to the multiple applications of random numbers in computer systems (cryptography, online gambling, computer simulation, etc.) it is important to have mechanisms to generate these numbers. True Random Number Generators (TRNGs) are commonly used for this purpose. TRNGs rely on non-deterministic sources to generate randomness. Physical processes (like noise in semiconductors, quantum phenomenon, etc.) play this role in state of the art TRNGs. In this paper, we depart from previous work and explore the possibility of defining social TRNGs using the stream of public messages of the microblogging service Twitter as randomness source. Thus, we define two TRNGs based on Twitter stream information and evaluate them using the National Institute of Standards and Technology (NIST) statistical test suite. The results of the evaluation confirm the feasibility of the proposed approach.
An investigation of the uniform random number generator
NASA Technical Reports Server (NTRS)
Temple, E. C.
1982-01-01
Most random number generators that are in use today are of the congruential form X(i+1) + AX(i) + C mod M where A, C, and M are nonnegative integers. If C=O, the generator is called the multiplicative type and those for which C/O are called mixed congruential generators. It is easy to see that congruential generators will repeat a sequence of numbers after a maximum of M values have been generated. The number of numbers that a procedure generates before restarting the sequence is called the length or the period of the generator. Generally, it is desirable to make the period as long as possible. A detailed discussion of congruential generators is given. Also, several promising procedures that differ from the multiplicative and mixed procedure are discussed.
Experimental measurement-device-independent quantum random-number generation
NASA Astrophysics Data System (ADS)
Nie, You-Qi; Guan, Jian-Yu; Zhou, Hongyi; Zhang, Qiang; Ma, Xiongfeng; Zhang, Jun; Pan, Jian-Wei
2016-12-01
The randomness from a quantum random-number generator (QRNG) relies on the accurate characterization of its devices. However, device imperfections and inaccurate characterizations can result in wrong entropy estimation and bias in practice, which highly affects the genuine randomness generation and may even induce the disappearance of quantum randomness in an extreme case. Here we experimentally demonstrate a measurement-device-independent (MDI) QRNG based on time-bin encoding to achieve certified quantum randomness even when the measurement devices are uncharacterized and untrusted. The MDI-QRNG is randomly switched between the regular randomness generation mode and a test mode, in which four quantum states are randomly prepared to perform measurement tomography in real time. With a clock rate of 25 MHz, the MDI-QRNG generates a final random bit rate of 5.7 kbps. Such implementation with an all-fiber setup provides an approach to construct a fully integrated MDI-QRNG with trusted but error-prone devices in practice.
Two-bit quantum random number generator based on photon-number-resolving detection
NASA Astrophysics Data System (ADS)
Jian, Yi; Ren, Min; Wu, E.; Wu, Guang; Zeng, Heping
2011-07-01
Here we present a new fast two-bit quantum random number generator based on the intrinsic randomness of the quantum physical phenomenon of photon statistics of coherent light source. Two-bit random numbers were generated according to the number of detected photons in each light pulse by a photon-number-resolving detector. Poissonian photon statistics of the coherent light source guaranteed the complete randomness of the bit sequences. Multi-bit true random numbers were generated for the first time based on the multi-photon events from a coherent light source.
Accelerating Pseudo-Random Number Generator for MCNP on GPU
NASA Astrophysics Data System (ADS)
Gong, Chunye; Liu, Jie; Chi, Lihua; Hu, Qingfeng; Deng, Li; Gong, Zhenghu
2010-09-01
Pseudo-random number generators (PRNG) are intensively used in many stochastic algorithms in particle simulations, artificial neural networks and other scientific computation. The PRNG in Monte Carlo N-Particle Transport Code (MCNP) requires long period, high quality, flexible jump and fast enough. In this paper, we implement such a PRNG for MCNP on NVIDIA's GTX200 Graphics Processor Units (GPU) using CUDA programming model. Results shows that 3.80 to 8.10 times speedup are achieved compared with 4 to 6 cores CPUs and more than 679.18 million double precision random numbers can be generated per second on GPU.
Acute peripheral vestibular deficit increases redundancy in random number generation.
Moser, Ivan; Vibert, Dominique; Caversaccio, Marco D; Mast, Fred W
2017-02-01
Unilateral peripheral vestibular deficit leads to broad cognitive difficulties and biases in spatial orientation. More specifically, vestibular patients typically show a spatial bias toward their affected ear in the subjective visual vertical, head and trunk orientation, fall tendency, and walking trajectory. By means of a random number generation task, we set out to investigate how an acute peripheral vestibular deficit affects the mental representation of numbers in space. Furthermore, the random number generation task allowed us to test if patients with peripheral vestibular deficit show evidence of impaired executive functions while keeping the head straight and while performing active head turns. Previous research using galvanic vestibular stimulation in healthy people has shown no effects on number space, but revealed increased redundancy of the generated numbers. Other studies reported a spatial bias in number representation during active and passive head turns. In this experiment, we tested 43 patients with acute vestibular neuritis (18 patients with left-sided and 25 with right-sided vestibular deficit) and 28 age-matched healthy controls. We found no bias in number space in patients with peripheral vestibular deficit but showed increased redundancy in patients during active head turns. Patients showed worse performance in generating sequences of random numbers, which indicates a deficit in the updating component of executive functions. We argue that RNG is a promising candidate for a time- and cost-effective assessment of executive functions in patients suffering from a peripheral vestibular deficit.
Testing, Selection, and Implementation of Random Number Generators
2008-07-01
U.S. Army Research Laboratory ATTN: AMSRD-ARL-SL-BD Aberdeen Proving Ground, MD 21005-5068 8 . PERFORMING ORGANIZATION REPORT NUMBER ARL...NUMBER (Include area code) 410-278-6832 Standard Form 298 (Rev. 8 /98) Prescribed by ANSI Std. Z39.18 ii Contents 1. Random Number Generators 1...Linear RNGs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.4.2 The Characteristic Polynomial
Ultrafast quantum random number generation based on quantum phase fluctuations.
Xu, Feihu; Qi, Bing; Ma, Xiongfeng; Xu, He; Zheng, Haoxuan; Lo, Hoi-Kwong
2012-05-21
A quantum random number generator (QRNG) can generate true randomness by exploiting the fundamental indeterminism of quantum mechanics. Most approaches to QRNG employ single-photon detection technologies and are limited in speed. Here, we experimentally demonstrate an ultrafast QRNG at a rate over 6 Gbits/s based on the quantum phase fluctuations of a laser operating near threshold. Moreover, we consider a potential adversary who has partial knowledge on the raw data and discuss how one can rigorously remove such partial knowledge with postprocessing. We quantify the quantum randomness through min-entropy by modeling our system and employ two randomness extractors--Trevisan's extractor and Toeplitz-hashing--to distill the randomness, which is information-theoretically provable. The simplicity and high-speed of our experimental setup show the feasibility of a robust, low-cost, high-speed QRNG.
Quantum random-number generator based on a photon-number-resolving detector
NASA Astrophysics Data System (ADS)
Ren, Min; Wu, E.; Liang, Yan; Jian, Yi; Wu, Guang; Zeng, Heping
2011-02-01
We demonstrated a high-efficiency quantum random number generator which takes inherent advantage of the photon number distribution randomness of a coherent light source. This scheme was realized by comparing the photon flux of consecutive pulses with a photon number resolving detector. The random bit generation rate could reach 2.4 MHz with a system clock of 6.0 MHz, corresponding to a random bit generation efficiency as high as 40%. The random number files passed all the stringent statistical tests.
Source-Device-Independent Ultrafast Quantum Random Number Generation
NASA Astrophysics Data System (ADS)
Marangon, Davide G.; Vallone, Giuseppe; Villoresi, Paolo
2017-02-01
Secure random numbers are a fundamental element of many applications in science, statistics, cryptography and more in general in security protocols. We present a method that enables the generation of high-speed unpredictable random numbers from the quadratures of an electromagnetic field without any assumption on the input state. The method allows us to eliminate the numbers that can be predicted due to the presence of classical and quantum side information. In particular, we introduce a procedure to estimate a bound on the conditional min-entropy based on the entropic uncertainty principle for position and momentum observables of infinite dimensional quantum systems. By the above method, we experimentally demonstrated the generation of secure true random bits at a rate greater than 1.7 Gbit /s .
Source-Device-Independent Ultrafast Quantum Random Number Generation.
Marangon, Davide G; Vallone, Giuseppe; Villoresi, Paolo
2017-02-10
Secure random numbers are a fundamental element of many applications in science, statistics, cryptography and more in general in security protocols. We present a method that enables the generation of high-speed unpredictable random numbers from the quadratures of an electromagnetic field without any assumption on the input state. The method allows us to eliminate the numbers that can be predicted due to the presence of classical and quantum side information. In particular, we introduce a procedure to estimate a bound on the conditional min-entropy based on the entropic uncertainty principle for position and momentum observables of infinite dimensional quantum systems. By the above method, we experimentally demonstrated the generation of secure true random bits at a rate greater than 1.7 Gbit/s.
GASPRNG: GPU accelerated scalable parallel random number generator library
NASA Astrophysics Data System (ADS)
Gao, Shuang; Peterson, Gregory D.
2013-04-01
Graphics processors represent a promising technology for accelerating computational science applications. Many computational science applications require fast and scalable random number generation with good statistical properties, so they use the Scalable Parallel Random Number Generators library (SPRNG). We present the GPU Accelerated SPRNG library (GASPRNG) to accelerate SPRNG in GPU-based high performance computing systems. GASPRNG includes code for a host CPU and CUDA code for execution on NVIDIA graphics processing units (GPUs) along with a programming interface to support various usage models for pseudorandom numbers and computational science applications executing on the CPU, GPU, or both. This paper describes the implementation approach used to produce high performance and also describes how to use the programming interface. The programming interface allows a user to be able to use GASPRNG the same way as SPRNG on traditional serial or parallel computers as well as to develop tightly coupled programs executing primarily on the GPU. We also describe how to install GASPRNG and use it. To help illustrate linking with GASPRNG, various demonstration codes are included for the different usage models. GASPRNG on a single GPU shows up to 280x speedup over SPRNG on a single CPU core and is able to scale for larger systems in the same manner as SPRNG. Because GASPRNG generates identical streams of pseudorandom numbers as SPRNG, users can be confident about the quality of GASPRNG for scalable computational science applications. Catalogue identifier: AEOI_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOI_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: UTK license. No. of lines in distributed program, including test data, etc.: 167900 No. of bytes in distributed program, including test data, etc.: 1422058 Distribution format: tar.gz Programming language: C and CUDA. Computer: Any PC or
DNA-based random number generation in security circuitry.
Gearheart, Christy M; Arazi, Benjamin; Rouchka, Eric C
2010-06-01
DNA-based circuit design is an area of research in which traditional silicon-based technologies are replaced by naturally occurring phenomena taken from biochemistry and molecular biology. This research focuses on further developing DNA-based methodologies to mimic digital data manipulation. While exhibiting fundamental principles, this work was done in conjunction with the vision that DNA-based circuitry, when the technology matures, will form the basis for a tamper-proof security module, revolutionizing the meaning and concept of tamper-proofing and possibly preventing it altogether based on accurate scientific observations. A paramount part of such a solution would be self-generation of random numbers. A novel prototype schema employs solid phase synthesis of oligonucleotides for random construction of DNA sequences; temporary storage and retrieval is achieved through plasmid vectors. A discussion of how to evaluate sequence randomness is included, as well as how these techniques are applied to a simulation of the random number generation circuitry. Simulation results show generated sequences successfully pass three selected NIST random number generation tests specified for security applications.
DNA-Based Random Number Generation in Security Circuitry
Gearheart, Christy M.; Arazi, Benjamin; Rouchka, Eric C.
2010-01-01
DNA-based circuit design is an area of research in which traditional silicon-based technologies are replaced by naturally occurring phenomena taken from biochemistry and molecular biology. This research focuses on further developing DNA-based methodologies to mimic digital data manipulation. While exhibiting fundamental principles, this work was done in conjunction with the vision that DNA-based circuitry, when the technology matures, will form the basis for a tamper-proof security module, revolutionizing the meaning and concept of tamper-proofing and possibly preventing it altogether based on accurate scientific observations. A paramount part of such a solution would be self-generation of random numbers. A novel prototype schema employs solid-phase synthesis of oligonucleotides for random construction of DNA sequences; temporary storage and retrieval is achieved through plasmid vectors. A discussion of how to evaluate sequence randomness is included, as well as how these techniques are applied to a simulation of the random number generation circuitry. Simulation results show generated sequences successfully pass three selected NIST random number generation tests specified for security applications. PMID:20303385
Random number generation in native and foreign languages.
Strenge, Hans; Bohm, Jessica
2004-06-01
The effects of different levels of language proficiency on random number generation were examined in this study. 16 healthy right-handed students (7 women, 9 men; aged 22 to 25 years, M=23.8, SD=.83) attempted to generate a random sequence of the digits 1 to 9 at pacing frequencies of 1, 1.5, and 2 Hz. Randomization was done in German (native language L1), English (first foreign language L2), and French (second foreign language L3). There was a pattern of redundancy and seriation tendencies, increasing with speed of generation for all languages (L1-L3). While using L2 and L3, responses slowed and the number of errors committed increased. Further, there was a peculiar pattern of dissociation in nonrandom performance with an increase of habitual counting in ones and a strong reduction of counting in twos. All effects were most pronounced when subjects used L3 and 2-Hz pacing rates. Slowing and nonrandomness was not correlated with self-assessment parameters regarding language proficiency. We suggest that in a task involving number activation in a nonnative language, lack of proficiency will interfere with random number generation, leading to interruptions and rule breaking, at least when reaching the limits of attentional capacity at higher pacing rates.
Testing random number generators for Monte Carlo applications.
Sim, L H; Nitschke, K N
1993-03-01
Central to any system for modelling radiation transport phenomena using Monte Carlo techniques is the method by which pseudo random numbers are generated. This method is commonly referred to as the Random Number Generator (RNG). It is usually a computer implemented mathematical algorithm which produces a series of numbers uniformly distributed on the interval [0,1). If this series satisfies certain statistical tests for randomness, then for practical purposes the pseudo random numbers in the series can be considered to be random. Tests of this nature are important not only for new RNGs but also to test the implementation of known RNG algorithms in different computer environments. Six RNGs have been tested using six statistical tests and one visual test. The statistical tests are the moments, frequency (digit and number), serial, gap, and poker tests. The visual test is a simple two dimensional ordered pair display. In addition the RNGs have been tested in a specific Monte Carlo application. This type of test is often overlooked, however it is important that in addition to satisfactory performance in statistical tests, the RNG be able to perform effectively in the applications of interest. The RNGs tested here are based on a variety of algorithms, including multiplicative and linear congruential, lagged Fibonacci, and combination arithmetic and lagged Fibonacci. The effect of the Bays-Durham shuffling algorithm on the output of a known "bad" RNG has also been investigated.
Analysis of entropy extraction efficiencies in random number generation systems
NASA Astrophysics Data System (ADS)
Wang, Chao; Wang, Shuang; Chen, Wei; Yin, Zhen-Qiang; Han, Zheng-Fu
2016-05-01
Random numbers (RNs) have applications in many areas: lottery games, gambling, computer simulation, and, most importantly, cryptography [N. Gisin et al., Rev. Mod. Phys. 74 (2002) 145]. In cryptography theory, the theoretical security of the system calls for high quality RNs. Therefore, developing methods for producing unpredictable RNs with adequate speed is an attractive topic. Early on, despite the lack of theoretical support, pseudo RNs generated by algorithmic methods performed well and satisfied reasonable statistical requirements. However, as implemented, those pseudorandom sequences were completely determined by mathematical formulas and initial seeds, which cannot introduce extra entropy or information. In these cases, “random” bits are generated that are not at all random. Physical random number generators (RNGs), which, in contrast to algorithmic methods, are based on unpredictable physical random phenomena, have attracted considerable research interest. However, the way that we extract random bits from those physical entropy sources has a large influence on the efficiency and performance of the system. In this manuscript, we will review and discuss several randomness extraction schemes that are based on radiation or photon arrival times. We analyze the robustness, post-processing requirements and, in particular, the extraction efficiency of those methods to aid in the construction of efficient, compact and robust physical RNG systems.
Enhanced security for multi-detector quantum random number generators
NASA Astrophysics Data System (ADS)
Marangon, Davide G.; Vallone, Giuseppe; Zanforlin, Ugo; Villoresi, Paolo
2016-11-01
Quantum random number generators (QRNG) represent an advanced solution for randomness generation, which is essential in every cryptographic application. In this context, integrated arrays of single-photon detectors have promising applications as QRNGs based on the spatial detection of photons. For the employment of QRNGs in cryptography, it is necessary to have efficient methods to evaluate the so-called quantum min-entropy that corresponds to the amount of the true extractable quantum randomness from the QRNG. Here, we present an efficient method that allows the estimation of the quantum min-entropy for a multi-detector QRNG. In particular, we consider a scenario in which an attacker can control the efficiency of the detectors and knows the emitted number of photons. Eventually, we apply the method to a QRNG with 103 detectors.
Robust Quantum Random Number Generator Based on Avalanche Photodiodes
NASA Astrophysics Data System (ADS)
Wang, Fang-Xiang; Wang, Chao; Chen, Wei; Wang, Shuang; Lv, Fu-Sheng; He, De-Yong; Yin, Zhen-Qiang; Li, Hong-Wei; Guo, Guang-Can; Han, Zheng-Fu
2015-08-01
We propose and demonstrate a scheme to realize a high-efficiency truly quantum random number generator (RNG) at room temperature (RT). Using an effective extractor with simple time bin encoding method, the avalanche pulses of avalanche photodiode (APD) are converted into high-quality random numbers (RNs) that are robust to slow varying noise such as fluctuations of pulse intensity and temperature. A light source is compatible but not necessary in this scheme. Therefor the robustness of the system is effective enhanced. The random bits generation rate of this proof-of-principle system is 0.69 Mbps with double APDs and 0.34 Mbps with single APD. The results indicate that a high-speed RNG chip based on the scheme is potentially available with an integrable APD array.
Fault tolerant quantum random number generator certified by Majorana fermions
NASA Astrophysics Data System (ADS)
Deng, Dong-Ling; Duan, Lu-Ming
2013-03-01
Braiding of Majorana fermions gives accurate topological quantum operations that are intrinsically robust to noise and imperfection, providing a natural method to realize fault-tolerant quantum information processing. Unfortunately, it is known that braiding of Majorana fermions is not sufficient for implementation of universal quantum computation. Here we show that topological manipulation of Majorana fermions provides the full set of operations required to generate random numbers by way of quantum mechanics and to certify its genuine randomness through violation of a multipartite Bell inequality. The result opens a new perspective to apply Majorana fermions for robust generation of certified random numbers, which has important applications in cryptography and other related areas. This work was supported by the NBRPC (973 Program) 2011CBA00300 (2011CBA00302), the IARPA MUSIQC program, the ARO and the AFOSR MURI program.
Solution-Processed Carbon Nanotube True Random Number Generator.
Gaviria Rojas, William A; McMorrow, Julian J; Geier, Michael L; Tang, Qianying; Kim, Chris H; Marks, Tobin J; Hersam, Mark C
2017-08-09
With the growing adoption of interconnected electronic devices in consumer and industrial applications, there is an increasing demand for robust security protocols when transmitting and receiving sensitive data. Toward this end, hardware true random number generators (TRNGs), commonly used to create encryption keys, offer significant advantages over software pseudorandom number generators. However, the vast network of devices and sensors envisioned for the "Internet of Things" will require small, low-cost, and mechanically flexible TRNGs with low computational complexity. These rigorous constraints position solution-processed semiconducting single-walled carbon nanotubes (SWCNTs) as leading candidates for next-generation security devices. Here, we demonstrate the first TRNG using static random access memory (SRAM) cells based on solution-processed SWCNTs that digitize thermal noise to generate random bits. This bit generation strategy can be readily implemented in hardware with minimal transistor and computational overhead, resulting in an output stream that passes standardized statistical tests for randomness. By using solution-processed semiconducting SWCNTs in a low-power, complementary architecture to achieve TRNG, we demonstrate a promising approach for improving the security of printable and flexible electronics.
Ghersi, Dario; Parakh, Abhishek; Mezei, Mihaly
2017-09-18
Four pseudorandom number generators were compared with a physical, quantum-based random number generator using the NIST suite of statistical tests, which only the quantum-based random number generator could successfully pass. We then measured the effect of the five random number generators on various calculated properties in different Markov-chain Monte Carlo simulations. Two types of systems were tested: conformational sampling of a small molecule in aqueous solution and liquid methanol under constant temperature and pressure. The results show that poor quality pseudorandom number generators produce results that deviate significantly from those obtained with the quantum-based random number generator, particularly in the case of the small molecule in aqueous solution setup. In contrast, the widely used Mersenne Twister pseudorandom generator and a 64-bit Linear Congruential Generator with a scrambler produce results that are statistically indistinguishable from those obtained with the quantum-based random number generator. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Quantum random number generators and their applications in cryptography
NASA Astrophysics Data System (ADS)
Stipcevic, Mario
2012-06-01
Random number generators (RNG) are an important resource in many areas: cryptography (both quantum and classical), probabilistic computation (Monte Carlo methods), numerical simulations, industrial testing and labeling, hazard games, scientific research etc. Because today's computers are deterministic, they can not create random numbers unless complemented with a physical RNG. Randomness of a RNG can be defined and scientifically characterized and measured. Especially valuable is the information-theoretic provable RNG which, at state of the art, seem to be possible only by harvest of randomness inherent to certain (simple) quantum systems and such a generator we call Quantum RNG (QRNG). On the other hand, current industry standards dictate use of RNGs based on free running oscillators (FRO) whose randomness is derived from electronics noise present in logic circuits and which, although quantum in nature, cannot be strictly proven. This approach is currently used in FPGA and ASIC chips. We compare weak and strong aspects of the two approaches for use in cryptography and in general. We also give an alternative definition of randomness, discuss usage of single photon detectors in realization of QRNGs and give several examples where QRNG can significantly improve security of a cryptographic system.
Random number generators tested on quantum Monte Carlo simulations.
Hongo, Kenta; Maezono, Ryo; Miura, Kenichi
2010-08-01
We have tested and compared several (pseudo) random number generators (RNGs) applied to a practical application, ground state energy calculations of molecules using variational and diffusion Monte Carlo metheds. A new multiple recursive generator with 8th-order recursion (MRG8) and the Mersenne twister generator (MT19937) are tested and compared with the RANLUX generator with five luxury levels (RANLUX-[0-4]). Both MRG8 and MT19937 are proven to give the same total energy as that evaluated with RANLUX-4 (highest luxury level) within the statistical error bars with less computational cost to generate the sequence. We also tested the notorious implementation of linear congruential generator (LCG), RANDU, for comparison.
Perceiving numbers affects the internal random movements generator.
Vicario, Carmelo Mario
2012-01-01
According to the evidence of direct relationships among space, numbers, and finger representations, a random movement generation (RMG) task was employed in order to investigate whether numerical exposure can influence the finger selection of healthy humans. To this purpose a group of participants were asked to generate random finger movements during the exposure to several numerical cues. Although participants were explicitly asked to move finger as random as possible, results showed that left-hand fingers were moved more frequently than right-hand fingers when low numerical cues (from 1 to 3) were presented, and, vice versa, right-hand fingers were moved more frequently than left-hand fingers when high numerical cues (ranged from 7 to 9) were presented. The current result suggests that spontaneous actions can be affected by abstract information, providing an evidence that numerical concepts can influence low-level, non-goal-directed behaviours.
Theory and Testing of Uniform Random Number Generators
1976-06-01
primitive root/ prime modulus random number generators which form a more general algebraic system, a finite field. The special properties of finite field...arithmetic will be developed and several new theorems will be presented regarding primitive roots of prime fields. Using these properties of finite...element a of the group there is an inverse denoted a such that a a = 1. The residues which are relatively prime to a general modulus m under the
NASA Astrophysics Data System (ADS)
Barash, L. Yu.; Shchur, L. N.
2013-10-01
In this update, we present the new version of the random number generator (RNG) library RNGSSELIB, which, in particular, contains fast SSE realizations of a number of modern and most reliable generators [1]. The new features are: (i) Fortran compatibility and examples of using the library in Fortran; (ii) new modern and reliable generators; (iii) the abilities to jump ahead inside a RNG sequence and to initialize up to 1019 independent random number streams with block splitting method. Summary of revisions: We added Fortran compatibility and examples of using the library in Fortran for each of the generators. New modern and reliable generators GM29, GM55.4, GQ58.1, GQ58.3, and GQ58.4, which were introduced in [5] were added to the library. The ability to jump ahead inside a RNG sequence and to initialize independent random number streams with block splitting method are added for each of the RNGs. Restrictions: For SSE realizations of the generators, the Intel or AMD CPU supporting SSE2 command set is required. In order to use the SSE realization for the lfsr113 generator, the CPU must support the SSE4.1 command set. Additional comments: The function call interface has been slightly modified compared to the previous version in order to support Fortran compatibility. For each of the generators, RNGSSELIB supports the following functions, where rng should be replaced by the particular name of the RNG: void rng_skipahead_(rng_state* state, unsigned long long offset); void rng_init_(rng_state* state); void rng_init_sequence_(rng_state* state,unsigned long long SequenceNumber); unsigned int rng_generate_(rng_state* state); float rng_generate_uniform_float_(rng_state* state); unsigned int rng_sse_generate_(rng_sse_state* state); void rng_get_sse_state_(rng_state* state,rng_sse_state* sse_state); void rng_print_state_(rng_state* state); void rng_print_sse_state_(rng_sse_state* state); There are a few peculiarities for some of the RNGs. For example, the function void mt
Postprocessing for quantum random-number generators: Entropy evaluation and randomness extraction
NASA Astrophysics Data System (ADS)
Ma, Xiongfeng; Xu, Feihu; Xu, He; Tan, Xiaoqing; Qi, Bing; Lo, Hoi-Kwong
2013-06-01
Quantum random-number generators (QRNGs) can offer a means to generate information-theoretically provable random numbers, in principle. In practice, unfortunately, the quantum randomness is inevitably mixed with classical randomness due to classical noises. To distill this quantum randomness, one needs to quantify the randomness of the source and apply a randomness extractor. Here, we propose a generic framework for evaluating quantum randomness of real-life QRNGs by min-entropy, and apply it to two different existing quantum random-number systems in the literature. Moreover, we provide a guideline of QRNG data postprocessing for which we implement two information-theoretically provable randomness extractors: Toeplitz-hashing extractor and Trevisan's extractor.
Implementing Quality Control on a Random Number Stream to Improve a Stochastic Weather Generator
USDA-ARS?s Scientific Manuscript database
For decades stochastic modelers have used computerized random number generators to produce random numeric sequences fitting a specified statistical distribution. Unfortunately, none of the random number generators we tested satisfactorily produced the target distribution. The result is generated d...
Quantum Statistical Testing of a Quantum Random Number Generator
Humble, Travis S
2014-01-01
The unobservable elements in a quantum technology, e.g., the quantum state, complicate system verification against promised behavior. Using model-based system engineering, we present methods for verifying the opera- tion of a prototypical quantum random number generator. We begin with the algorithmic design of the QRNG followed by the synthesis of its physical design requirements. We next discuss how quantum statistical testing can be used to verify device behavior as well as detect device bias. We conclude by highlighting how system design and verification methods must influence effort to certify future quantum technologies.
Quantum statistical testing of a quantum random number generator
NASA Astrophysics Data System (ADS)
Humble, Travis S.
2014-10-01
The unobservable elements in a quantum technology, e.g., the quantum state, complicate system verification against promised behavior. Using model-based system engineering, we present methods for verifying the operation of a prototypical quantum random number generator. We begin with the algorithmic design of the QRNG followed by the synthesis of its physical design requirements. We next discuss how quantum statistical testing can be used to verify device behavior as well as detect device bias. We conclude by highlighting how system design and verification methods must influence effort to certify future quantum technologies.
Strenge, Hans; Rogge, Carolin
2010-04-01
The effects of different instructions on verbal random number generation were examined in 40 healthy students who attempted to generate random sequences of the digits 1 to 6. Two groups of 20 received different instructions with alternative numerical representations. The Symbolic group (Arabic digits) was instructed to randomize while continuously using the analogy of selecting and replacing numbered balls from a hat, whereas the Nonsymbolic group (arrays of dots) was instructed to imagine repeatedly throwing a die. Participants asked for self-reports on their strategies reported spontaneously occurring visuospatial imagination of a mental number line (42%), or imagining throwing a die (23%). Individual number representation was not affected by the initial instruction. There were no differences in randomization performance by group. Comprehensive understanding of the nature of the randomization task requires considering individual differences in construction of mental models.
Pseudo random number generator based on quantum chaotic map
NASA Astrophysics Data System (ADS)
Akhshani, A.; Akhavan, A.; Mobaraki, A.; Lim, S.-C.; Hassan, Z.
2014-01-01
For many years dissipative quantum maps were widely used as informative models of quantum chaos. In this paper, a new scheme for generating good pseudo-random numbers (PRNG), based on quantum logistic map is proposed. Note that the PRNG merely relies on the equations used in the quantum chaotic map. The algorithm is not complex, which does not impose high requirement on computer hardware and thus computation speed is fast. In order to face the challenge of using the proposed PRNG in quantum cryptography and other practical applications, the proposed PRNG is subjected to statistical tests using well-known test suites such as NIST, DIEHARD, ENT and TestU01. The results of the statistical tests were promising, as the proposed PRNG successfully passed all these tests. Moreover, the degree of non-periodicity of the chaotic sequences of the quantum map is investigated through the Scale index technique. The obtained result shows that, the sequence is more non-periodic. From these results it can be concluded that, the new scheme can generate a high percentage of usable pseudo-random numbers for simulation and other applications in scientific computing.
FPGA Implementation of Metastability-Based True Random Number Generator
NASA Astrophysics Data System (ADS)
Hata, Hisashi; Ichikawa, Shuichi
True random number generators (TRNGs) are important as a basis for computer security. Though there are some TRNGs composed of analog circuit, the use of digital circuits is desired for the application of TRNGs to logic LSIs. Some of the digital TRNGs utilize jitter in free-running ring oscillators as a source of entropy, which consume large power. Another type of TRNG exploits the metastability of a latch to generate entropy. Although this kind of TRNG has been mostly implemented with full-custom LSI technology, this study presents an implementation based on common FPGA technology. Our TRNG is comprised of logic gates only, and can be integrated in any kind of logic LSI. The RS latch in our TRNG is implemented as a hard-macro to guarantee the quality of randomness by minimizing the signal skew and load imbalance of internal nodes. To improve the quality and throughput, the output of 64-256 latches are XOR'ed. The derived design was verified on a Xilinx Virtex-4 FPGA (XC4VFX20), and passed NIST statistical test suite without post-processing. Our TRNG with 256 latches occupies 580 slices, while achieving 12.5Mbps throughput.
Statistical evaluation of PACSTAT random number generation capabilities
Piepel, G.F.; Toland, M.R.; Harty, H.; Budden, M.J.; Bartley, C.L.
1988-05-01
This report summarizes the work performed in verifying the general purpose Monte Carlo driver-program PACSTAT. The main objective of the work was to verify the performance of PACSTAT's random number generation capabilities. Secondary objectives were to document (using controlled configuration management procedures) changes made in PACSTAT at Pacific Northwest Laboratory, and to assure that PACSTAT input and output files satisfy quality assurance traceability constraints. Upon receipt of the PRIME version of the PACSTAT code from the Basalt Waste Isolation Project, Pacific Northwest Laboratory staff converted the code to run on Digital Equipment Corporation (DEC) VAXs. The modifications to PACSTAT were implemented using the WITNESS configuration management system, with the modifications themselves intended to make the code as portable as possible. Certain modifications were made to make the PACSTAT input and output files conform to quality assurance traceability constraints. 10 refs., 17 figs., 6 tabs.
Manipulating attentional load in sequence learning through random number generation.
Wierzchoń, Michał; Gaillard, Vinciane; Asanowicz, Dariusz; Cleeremans, Axel
2012-01-01
Implicit learning is often assumed to be an effortless process. However, some artificial grammar learning and sequence learning studies using dual tasks seem to suggest that attention is essential for implicit learning to occur. This discrepancy probably results from the specific type of secondary task that is used. Different secondary tasks may engage attentional resources differently and therefore may bias performance on the primary task in different ways. Here, we used a random number generation (RNG) task, which may allow for a closer monitoring of a participant's engagement in a secondary task than the popular secondary task in sequence learning studies: tone counting (TC). In the first two experiments, we investigated the interference associated with performing RNG concurrently with a serial reaction time (SRT) task. In a third experiment, we compared the effects of RNG and TC. In all three experiments, we directly evaluated participants' knowledge of the sequence with a subsequent sequence generation task. Sequence learning was consistently observed in all experiments, but was impaired under dual-task conditions. Most importantly, our data suggest that RNG is more demanding and impairs learning to a greater extent than TC. Nevertheless, we failed to observe effects of the secondary task in subsequent sequence generation. Our studies indicate that RNG is a promising task to explore the involvement of attention in the SRT task.
Manipulating attentional load in sequence learning through random number generation
Wierzchoń, Michał; Gaillard, Vinciane; Asanowicz, Dariusz; Cleeremans, Axel
2012-01-01
Implicit learning is often assumed to be an effortless process. However, some artificial grammar learning and sequence learning studies using dual tasks seem to suggest that attention is essential for implicit learning to occur. This discrepancy probably results from the specific type of secondary task that is used. Different secondary tasks may engage attentional resources differently and therefore may bias performance on the primary task in different ways. Here, we used a random number generation (RNG) task, which may allow for a closer monitoring of a participant’s engagement in a secondary task than the popular secondary task in sequence learning studies: tone counting (TC). In the first two experiments, we investigated the interference associated with performing RNG concurrently with a serial reaction time (SRT) task. In a third experiment, we compared the effects of RNG and TC. In all three experiments, we directly evaluated participants’ knowledge of the sequence with a subsequent sequence generation task. Sequence learning was consistently observed in all experiments, but was impaired under dual-task conditions. Most importantly, our data suggest that RNG is more demanding and impairs learning to a greater extent than TC. Nevertheless, we failed to observe effects of the secondary task in subsequent sequence generation. Our studies indicate that RNG is a promising task to explore the involvement of attention in the SRT task. PMID:22723816
Efficient Raman generation in a waveguide: A route to ultrafast quantum random number generation
England, D. G.; Bustard, P. J.; Moffatt, D. J.; Nunn, J.; Lausten, R.; Sussman, B. J.
2014-02-03
The inherent uncertainty in quantum mechanics offers a source of true randomness which can be used to produce unbreakable cryptographic keys. We discuss the development of a high-speed random number generator based on the quantum phase fluctuations in spontaneously initiated stimulated Raman scattering (SISRS). We utilize the tight confinement and long interaction length available in a Potassium Titanyl Phosphate waveguide to generate highly efficient SISRS using nanojoule pulse energies, reducing the high pump power requirements of the previous approaches. We measure the random phase of the Stokes output using a simple interferometric setup to yield quantum random numbers at 145 Mbps.
Efficient Raman generation in a waveguide: A route to ultrafast quantum random number generation
NASA Astrophysics Data System (ADS)
England, D. G.; Bustard, P. J.; Moffatt, D. J.; Nunn, J.; Lausten, R.; Sussman, B. J.
2014-02-01
The inherent uncertainty in quantum mechanics offers a source of true randomness which can be used to produce unbreakable cryptographic keys. We discuss the development of a high-speed random number generator based on the quantum phase fluctuations in spontaneously initiated stimulated Raman scattering (SISRS). We utilize the tight confinement and long interaction length available in a Potassium Titanyl Phosphate waveguide to generate highly efficient SISRS using nanojoule pulse energies, reducing the high pump power requirements of the previous approaches. We measure the random phase of the Stokes output using a simple interferometric setup to yield quantum random numbers at 145 Mbps.
NASA Astrophysics Data System (ADS)
Cieśla, Michał
2017-01-01
The properties of the number of iterations in random sequential adsorption protocol needed to generate finite saturated random packing of spherically symmetric shapes were studied. Numerical results obtained for one, two, and three dimensional packings were supported by analytical calculations valid for any dimension d. It has been shown that the number of iterations needed to generate finite saturated packing is subject to Pareto distribution with exponent -1-1/d and the median of this distribution scales with packing size according to the power-law characterized by exponent d. Obtained results can be used in designing effective random sequential adsorption simulations.
Maximization of Extractable Randomness in a Quantum Random-Number Generator
NASA Astrophysics Data System (ADS)
Haw, J. Y.; Assad, S. M.; Lance, A. M.; Ng, N. H. Y.; Sharma, V.; Lam, P. K.; Symul, T.
2015-05-01
The generation of random numbers via quantum processes is an efficient and reliable method to obtain true indeterministic random numbers that are of vital importance to cryptographic communication and large-scale computer modeling. However, in realistic scenarios, the raw output of a quantum random-number generator is inevitably tainted by classical technical noise. The integrity of the device can be compromised if this noise is tampered with or even controlled by some malicious party. To safeguard against this, we propose and experimentally demonstrate an approach that produces side-information-independent randomness that is quantified by min-entropy conditioned on this classical noise. We present a method for maximizing the conditional min entropy of the number sequence generated from a given quantum-to-classical-noise ratio. The detected photocurrent in our experiment is shown to have a real-time random-number generation rate of 14 (Mb i t /s )/MHz . The spectral response of the detection system shows the potential to deliver more than 70 Gbit /s of random numbers in our experimental setup.
Efficient and robust quantum random number generation by photon number detection
Applegate, M. J.; Thomas, O.; Dynes, J. F.; Yuan, Z. L.; Shields, A. J.; Ritchie, D. A.
2015-08-17
We present an efficient and robust quantum random number generator based upon high-rate room temperature photon number detection. We employ an electric field-modulated silicon avalanche photodiode, a type of device particularly suited to high-rate photon number detection with excellent photon number resolution to detect, without an applied dead-time, up to 4 photons from the optical pulses emitted by a laser. By both measuring and modeling the response of the detector to the incident photons, we are able to determine the illumination conditions that achieve an optimal bit rate that we show is robust against variation in the photon flux. We extract random bits from the detected photon numbers with an efficiency of 99% corresponding to 1.97 bits per detected photon number yielding a bit rate of 143 Mbit/s, and verify that the extracted bits pass stringent statistical tests for randomness. Our scheme is highly scalable and has the potential of multi-Gbit/s bit rates.
Efficient and robust quantum random number generation by photon number detection
NASA Astrophysics Data System (ADS)
Applegate, M. J.; Thomas, O.; Dynes, J. F.; Yuan, Z. L.; Ritchie, D. A.; Shields, A. J.
2015-08-01
We present an efficient and robust quantum random number generator based upon high-rate room temperature photon number detection. We employ an electric field-modulated silicon avalanche photodiode, a type of device particularly suited to high-rate photon number detection with excellent photon number resolution to detect, without an applied dead-time, up to 4 photons from the optical pulses emitted by a laser. By both measuring and modeling the response of the detector to the incident photons, we are able to determine the illumination conditions that achieve an optimal bit rate that we show is robust against variation in the photon flux. We extract random bits from the detected photon numbers with an efficiency of 99% corresponding to 1.97 bits per detected photon number yielding a bit rate of 143 Mbit/s, and verify that the extracted bits pass stringent statistical tests for randomness. Our scheme is highly scalable and has the potential of multi-Gbit/s bit rates.
Some Efficient Random Number Generators for Micro Computers.
1983-09-01
bytt:bytel; CONST 1IKLT z 1221; ( other good values are: 2937, 393, 4199, 4293,) b5in ( 9237,14789,15125,17245) seed.int : MULT I sed.int +; Rlyte...Ili](B) Z ..X ....... X ........ x ........ S A * *-------- Figure I: Relationship betueen bits in a Tausuorthe sequence. Here B) is defined as a...Ii]c )R od@ -----------------------------I *here li] = the i-th number produced by the generator. Ii+I] the (i41)-th number produced by the geerator
Using Computer-Generated Random Numbers to Calculate the Lifetime of a Comet.
ERIC Educational Resources Information Center
Danesh, Iraj
1991-01-01
An educational technique to calculate the lifetime of a comet using software-generated random numbers is introduced to undergraduate physiques and astronomy students. Discussed are the generation and eligibility of the required random numbers, background literature related to the problem, and the solution to the problem using random numbers.…
Using Computer-Generated Random Numbers to Calculate the Lifetime of a Comet.
ERIC Educational Resources Information Center
Danesh, Iraj
1991-01-01
An educational technique to calculate the lifetime of a comet using software-generated random numbers is introduced to undergraduate physiques and astronomy students. Discussed are the generation and eligibility of the required random numbers, background literature related to the problem, and the solution to the problem using random numbers.…
Studies of random number generators for parallel processing
Bowman, K.O.; Robinson, M.T.
1986-09-01
If Monte Carlo calculations are to be performed in a parallel processing environment, a method of generating appropriate sequences of pseudorandom numbers for each process must be available. Frederickson et al. proposed an elegant algorithm based on the concept of pseudorandom or Lehmer trees: the sequence of numbers from a linear congruential generator is divided into disjoint subsequences by the members of an auxilary sequence. One subsequence can be assigned to each process. Extensive tests show the algorithm to suffer from correlations between the parallel subsequences: this is a result of the small number of bits which particpate in the auxiliary sequence and illustrates the well-known discovery of Marsaglia. Two alternative algorithms are proposed, both of which appear to be free of interprocess correlations. One relaxes the conditions on the Lehmer tree by using an arbitrary auxiliary multiplier: it is not known to what extent the subsequences are disjoint. The other partitions the main sequence into disjoint subsequences by sending one member to each process in turn, minimizing interprocess communication by defining new sequence generating parameters. 10 refs., 4 figs.
Persaud, Navindra
2005-01-01
Computer algorithms can only produce seemingly random or pseudorandom numbers whereas certain natural phenomena, such as the decay of radioactive particles, can be utilized to produce truly random numbers. In this study, the ability of humans to generate random numbers was tested in healthy adults. Subjects were simply asked to generate and dictate random numbers. Generated numbers were tested for uniformity, independence and information density. The results suggest that humans can generate random numbers that are uniformly distributed, independent of one another and unpredictable. If humans can generate sequences of random numbers then neural networks or forms of artificial intelligence, which are purported to function in ways essentially the same as the human brain, should also be able to generate sequences of random numbers. Elucidating the precise mechanism by which humans generate random number sequences and the underlying neural substrates may have implications in the cognitive science of decision-making. It is possible that humans use their random-generating neural machinery to make difficult decisions in which all expected outcomes are similar. It is also possible that certain people, perhaps those with neurological or psychiatric impairments, are less able or unable to generate random numbers. If the random-generating neural machinery is employed in decision making its impairment would have profound implications in matters of agency and free will.
Anosov C-systems and random number generators
NASA Astrophysics Data System (ADS)
Savvidy, G. K.
2016-08-01
We further develop our previous proposal to use hyperbolic Anosov C-systems to generate pseudorandom numbers and to use them for efficient Monte Carlo calculations in high energy particle physics. All trajectories of hyperbolic dynamical systems are exponentially unstable, and C-systems therefore have mixing of all orders, a countable Lebesgue spectrum, and a positive Kolmogorov entropy. These exceptional ergodic properties follow from the C-condition introduced by Anosov. This condition defines a rich class of dynamical systems forming an open set in the space of all dynamical systems. An important property of C-systems is that they have a countable set of everywhere dense periodic trajectories and their density increases exponentially with entropy. Of special interest are the C-systems defined on higher-dimensional tori. Such C-systems are excellent candidates for generating pseudorandom numbers that can be used in Monte Carlo calculations. An efficient algorithm was recently constructed that allows generating long C-system trajectories very rapidly. These trajectories have good statistical properties and can be used for calculations in quantum chromodynamics and in high energy particle physics.
Stipčević, Mario
2016-03-15
In this work, a new type of elementary logic circuit, named random flip-flop (RFF), is proposed, experimentally realized, and studied. Unlike conventional Boolean logic circuits whose action is deterministic and highly reproducible, the action of a RFF is intentionally made maximally unpredictable and, in the proposed realization, derived from a fundamentally random process of emission and detection of light quanta. We demonstrate novel applications of RFF in randomness preserving frequency division, random frequency synthesis, and random number generation. Possible usages of these applications in the information and communication technology, cryptographic hardware, and testing equipment are discussed.
Real-time fast physical random number generator with a photonic integrated circuit.
Ugajin, Kazusa; Terashima, Yuta; Iwakawa, Kento; Uchida, Atsushi; Harayama, Takahisa; Yoshimura, Kazuyuki; Inubushi, Masanobu
2017-03-20
Random number generators are essential for applications in information security and numerical simulations. Most optical-chaos-based random number generators produce random bit sequences by offline post-processing with large optical components. We demonstrate a real-time hardware implementation of a fast physical random number generator with a photonic integrated circuit and a field programmable gate array (FPGA) electronic board. We generate 1-Tbit random bit sequences and evaluate their statistical randomness using NIST Special Publication 800-22 and TestU01. All of the BigCrush tests in TestU01 are passed using 410-Gbit random bit sequences. A maximum real-time generation rate of 21.1 Gb/s is achieved for random bit sequences in binary format stored in a computer, which can be directly used for applications involving secret keys in cryptography and random seeds in large-scale numerical simulations.
Multi-bit quantum random number generation by measuring positions of arrival photons
Yan, Qiurong; Zhao, Baosheng; Liao, Qinghong; Zhou, Nanrun
2014-10-15
We report upon the realization of a novel multi-bit optical quantum random number generator by continuously measuring the arrival positions of photon emitted from a LED using MCP-based WSA photon counting imaging detector. A spatial encoding method is proposed to extract multi-bits random number from the position coordinates of each detected photon. The randomness of bits sequence relies on the intrinsic randomness of the quantum physical processes of photonic emission and subsequent photoelectric conversion. A prototype has been built and the random bit generation rate could reach 8 Mbit/s, with random bit generation efficiency of 16 bits per detected photon. FPGA implementation of Huffman coding is proposed to reduce the bias of raw extracted random bits. The random numbers passed all tests for physical random number generator.
Multi-bit quantum random number generation by measuring positions of arrival photons
NASA Astrophysics Data System (ADS)
Yan, Qiurong; Zhao, Baosheng; Liao, Qinghong; Zhou, Nanrun
2014-10-01
We report upon the realization of a novel multi-bit optical quantum random number generator by continuously measuring the arrival positions of photon emitted from a LED using MCP-based WSA photon counting imaging detector. A spatial encoding method is proposed to extract multi-bits random number from the position coordinates of each detected photon. The randomness of bits sequence relies on the intrinsic randomness of the quantum physical processes of photonic emission and subsequent photoelectric conversion. A prototype has been built and the random bit generation rate could reach 8 Mbit/s, with random bit generation efficiency of 16 bits per detected photon. FPGA implementation of Huffman coding is proposed to reduce the bias of raw extracted random bits. The random numbers passed all tests for physical random number generator.
a Pseudo-Random Number Generator Employing Multiple RÉNYI Maps
NASA Astrophysics Data System (ADS)
Lui, Oi-Yan; Yuen, Ching-Hung; Wong, Kwok-Wo
2013-11-01
The increasing risk along with the drastic development of multimedia data transmission has raised a big concern on data security. A good pseudo-random number generator is an essential tool in cryptography. In this paper, we propose a novel pseudo-random number generator based on the controlled combination of the outputs of several digitized chaotic Rényi maps. The generated pseudo-random sequences have passed both the NIST 800-22 Revision 1a and the DIEHARD tests. Moreover, simulation results show that the proposed pseudo-random number generator requires less operation time than existing generators and is highly sensitive to the seed.
A generator for unique quantum random numbers based on vacuum states
NASA Astrophysics Data System (ADS)
Gabriel, Christian; Wittmann, Christoffer; Sych, Denis; Dong, Ruifang; Mauerer, Wolfgang; Andersen, Ulrik L.; Marquardt, Christoph; Leuchs, Gerd
2010-10-01
Random numbers are a valuable component in diverse applications that range from simulations over gambling to cryptography. The quest for true randomness in these applications has engendered a large variety of different proposals for producing random numbers based on the foundational unpredictability of quantum mechanics. However, most approaches do not consider that a potential adversary could have knowledge about the generated numbers, so the numbers are not verifiably random and unique. Here we present a simple experimental setup based on homodyne measurements that uses the purity of a continuous-variable quantum vacuum state to generate unique random numbers. We use the intrinsic randomness in measuring the quadratures of a mode in the lowest energy vacuum state, which cannot be correlated to any other state. The simplicity of our source, combined with its verifiably unique randomness, are important attributes for achieving high-reliability, high-speed and low-cost quantum random number generators.
Novel pseudo-random number generator based on quantum random walks
Yang, Yu-Guang; Zhao, Qian-Qian
2016-01-01
In this paper, we investigate the potential application of quantum computation for constructing pseudo-random number generators (PRNGs) and further construct a novel PRNG based on quantum random walks (QRWs), a famous quantum computation model. The PRNG merely relies on the equations used in the QRWs, and thus the generation algorithm is simple and the computation speed is fast. The proposed PRNG is subjected to statistical tests such as NIST and successfully passed the test. Compared with the representative PRNG based on quantum chaotic maps (QCM), the present QRWs-based PRNG has some advantages such as better statistical complexity and recurrence. For example, the normalized Shannon entropy and the statistical complexity of the QRWs-based PRNG are 0.999699456771172 and 1.799961178212329e-04 respectively given the number of 8 bits-words, say, 16Mbits. By contrast, the corresponding values of the QCM-based PRNG are 0.999448131481064 and 3.701210794388818e-04 respectively. Thus the statistical complexity and the normalized entropy of the QRWs-based PRNG are closer to 0 and 1 respectively than those of the QCM-based PRNG when the number of words of the analyzed sequence increases. It provides a new clue to construct PRNGs and also extends the applications of quantum computation. PMID:26842402
Novel pseudo-random number generator based on quantum random walks.
Yang, Yu-Guang; Zhao, Qian-Qian
2016-02-04
In this paper, we investigate the potential application of quantum computation for constructing pseudo-random number generators (PRNGs) and further construct a novel PRNG based on quantum random walks (QRWs), a famous quantum computation model. The PRNG merely relies on the equations used in the QRWs, and thus the generation algorithm is simple and the computation speed is fast. The proposed PRNG is subjected to statistical tests such as NIST and successfully passed the test. Compared with the representative PRNG based on quantum chaotic maps (QCM), the present QRWs-based PRNG has some advantages such as better statistical complexity and recurrence. For example, the normalized Shannon entropy and the statistical complexity of the QRWs-based PRNG are 0.999699456771172 and 1.799961178212329e-04 respectively given the number of 8 bits-words, say, 16Mbits. By contrast, the corresponding values of the QCM-based PRNG are 0.999448131481064 and 3.701210794388818e-04 respectively. Thus the statistical complexity and the normalized entropy of the QRWs-based PRNG are closer to 0 and 1 respectively than those of the QCM-based PRNG when the number of words of the analyzed sequence increases. It provides a new clue to construct PRNGs and also extends the applications of quantum computation.
Novel pseudo-random number generator based on quantum random walks
NASA Astrophysics Data System (ADS)
Yang, Yu-Guang; Zhao, Qian-Qian
2016-02-01
In this paper, we investigate the potential application of quantum computation for constructing pseudo-random number generators (PRNGs) and further construct a novel PRNG based on quantum random walks (QRWs), a famous quantum computation model. The PRNG merely relies on the equations used in the QRWs, and thus the generation algorithm is simple and the computation speed is fast. The proposed PRNG is subjected to statistical tests such as NIST and successfully passed the test. Compared with the representative PRNG based on quantum chaotic maps (QCM), the present QRWs-based PRNG has some advantages such as better statistical complexity and recurrence. For example, the normalized Shannon entropy and the statistical complexity of the QRWs-based PRNG are 0.999699456771172 and 1.799961178212329e-04 respectively given the number of 8 bits-words, say, 16Mbits. By contrast, the corresponding values of the QCM-based PRNG are 0.999448131481064 and 3.701210794388818e-04 respectively. Thus the statistical complexity and the normalized entropy of the QRWs-based PRNG are closer to 0 and 1 respectively than those of the QCM-based PRNG when the number of words of the analyzed sequence increases. It provides a new clue to construct PRNGs and also extends the applications of quantum computation.
25 CFR 547.14 - What are the minimum technical standards for electronic random number generation?
Code of Federal Regulations, 2010 CFR
2010-04-01
... 25 Indians 2 2010-04-01 2010-04-01 false What are the minimum technical standards for electronic random number generation? 547.14 Section 547.14 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF... CLASS II GAMES § 547.14 What are the minimum technical standards for electronic random number generation...
54 Gbps real time quantum random number generator with simple implementation
NASA Astrophysics Data System (ADS)
Yang, Jie; Liu, Jinlu; Su, Qi; Li, Zhengyu; Fan, Fan; Xu, Bingjie; Guo, Hong
2016-11-01
We present a random number generation scheme based on measuring the phase fluctuations of a laser with a simple and compact experimental setup. A simple model is established to analyze the randomness and the simulation result based on this model fits well with the experiment data. After the analog to digital sampling and suitable randomness extraction integrated in the field programmable gate array, the final random bits are delivered to a PC, realizing a 5.4 Gbps real time quantum random number generation. The final random bit sequences have passed all the NIST and DIEHARD tests.
Fast random number generation with spontaneous emission noise of a single-mode semiconductor laser
NASA Astrophysics Data System (ADS)
Zhang, Jianzhong; Zhang, Mingjiang; Liu, Yi; Li, Pu; Yi, Xiaogang; Zhang, Mingtao; Wang, Yuncai
2016-11-01
We experimentally demonstrate a 12.5 Gb s-1 random number generator based on measuring the spontaneous emission noise of a single-mode semiconductor laser. The spontaneous emission of light is quantum mechanical in nature and is an inborn physical entropy source of true randomness. By combining a high-speed analog-to-digital converter and off-line processing, random numbers are extracted from the spontaneous emission with the verified randomness. The generator is simple, robust, and with no need of accurately tuning the comparison threshold. The use of semiconductor lasers makes it particularly compatible with the delivery of random numbers in optical networks.
NASA Astrophysics Data System (ADS)
Nie, You-Qi; Zhang, Hong-Fei; Zhang, Zhen; Wang, Jian; Ma, Xiongfeng; Zhang, Jun; Pan, Jian-Wei
2014-02-01
We present a practical high-speed quantum random number generator, where the timing of single-photon detection relative to an external time reference is measured as the raw data. The bias of the raw data can be substantially reduced compared with the previous realizations. The raw random bit rate of our generator can reach 109 Mbps. We develop a model for the generator and evaluate the min-entropy of the raw data. Toeplitz matrix hashing is applied for randomness extraction, after which the final random bits are able to pass the standard randomness tests.
Doing Better by Getting Worse: Posthypnotic Amnesia Improves Random Number Generation
Terhune, Devin Blair; Brugger, Peter
2011-01-01
Although forgetting is often regarded as a deficit that we need to control to optimize cognitive functioning, it can have beneficial effects in a number of contexts. We examined whether disrupting memory for previous numerical responses would attenuate repetition avoidance (the tendency to avoid repeating the same number) during random number generation and thereby improve the randomness of responses. Low suggestible and low dissociative and high dissociative highly suggestible individuals completed a random number generation task in a control condition, following a posthypnotic amnesia suggestion to forget previous numerical responses, and in a second control condition following the cancellation of the suggestion. High dissociative highly suggestible participants displayed a selective increase in repetitions during posthypnotic amnesia, with equivalent repetition frequency to a random system, whereas the other two groups exhibited repetition avoidance across conditions. Our results demonstrate that temporarily disrupting memory for previous numerical responses improves random number generation. PMID:22195022
Limitations of a True Random Number Generator in a Field Programmable Gate Array
2007-12-01
more hardware than addition. The first two numbers for a sequence from a Fibonacci generator must be supplied and generally m is usually chosen as...congruential generator with a lagged Fibonacci generator. The two generators should produce a good random sequence and tested to make sure the resulting...9 Figure 3 Von Neumann and Xor Corrector for Unbiasing Random Sequences ............. 10 Figure 4 Four Bit Linear
High-speed quantum-random number generation by continuous measurement of arrival time of photons
Yan, Qiurong; Zhao, Baosheng; Hua, Zhang; Liao, Qinghong; Yang, Hao
2015-07-15
We demonstrate a novel high speed and multi-bit optical quantum random number generator by continuously measuring arrival time of photons with a common starting point. To obtain the unbiased and post-processing free random bits, the measured photon arrival time is converted into the sum of integral multiple of a fixed period and a phase time. Theoretical and experimental results show that the phase time is an independent and uniform random variable. A random bit extraction method by encoding the phase time is proposed. An experimental setup has been built and the unbiased random bit generation rate could reach 128 Mb/s, with random bit generation efficiency of 8 bits per detected photon. The random numbers passed all tests in the statistical test suite.
High-speed quantum-random number generation by continuous measurement of arrival time of photons
NASA Astrophysics Data System (ADS)
Yan, Qiurong; Zhao, Baosheng; Hua, Zhang; Liao, Qinghong; Yang, Hao
2015-07-01
We demonstrate a novel high speed and multi-bit optical quantum random number generator by continuously measuring arrival time of photons with a common starting point. To obtain the unbiased and post-processing free random bits, the measured photon arrival time is converted into the sum of integral multiple of a fixed period and a phase time. Theoretical and experimental results show that the phase time is an independent and uniform random variable. A random bit extraction method by encoding the phase time is proposed. An experimental setup has been built and the unbiased random bit generation rate could reach 128 Mb/s, with random bit generation efficiency of 8 bits per detected photon. The random numbers passed all tests in the statistical test suite.
High-speed True Random Number Generation Based on Paired Memristors for Security Electronics.
Zhang, Teng; Yin, Minghui; Xu, Changmin; Lu, Xiayan; Sun, Xinhao; Yang, Yuchao; Huang, Ru
2017-09-08
True random number generator (TRNG) is a critical component in hardware security that is increasingly important in the era of mobile computing and Internet of Things. Here we demonstrate a TRNG using intrinsic variation of memristors as a natural source of entropy that is otherwise undesirable in most applications. The random bits were produced by cyclically switching a pair of tantalum oxide based memristors and comparing their resistance values in the off state, taking advantage of the more pronounced resistance variation compared with that in the on state. Using an alternating read scheme in the designed TRNG circuit, the unbiasedness of the random numbers was significantly improved, and the bitstream passed standard randomness tests. The Pt/TaOx/Ta memristors fabricated in this work have fast programming/erasing speeds of ~30 ns, suggesting a high random number throughput. The approach proposed here thus holds great promise for physically-implemented random number generation. © 2017 IOP Publishing Ltd.
Note: A 10 Gbps real-time post-processing free physical random number generator chip
NASA Astrophysics Data System (ADS)
Qian, Yi; Liang, Futian; Wang, Xinzhe; Li, Feng; Chen, Lian; Jin, Ge
2017-09-01
A random number generator with high data rate, small size, and low power consumption is essential for a certain quantum key distribution (QKD) system. We designed a 10 Gbps random number generator ASIC, TRNG2016, for the QKD system. With a 6 mm × 6 mm QFN48 package, TRNG2016 has 10 independent physical random number generation channels, and each channel can work at a fixed frequency up to 1 Gbps. The random number generated by TRNG2016 can pass the NIST statistical tests without any post-processing. With 3.3 V IO power supply and 1.2 V core power supply, the typical power consumption of TRNG2016 is 773 mW with 10 channels on and running at 1 Gbps data rate.
Recommendations and illustrations for the evaluation of photonic random number generators
NASA Astrophysics Data System (ADS)
Hart, Joseph D.; Terashima, Yuta; Uchida, Atsushi; Baumgartner, Gerald B.; Murphy, Thomas E.; Roy, Rajarshi
2017-09-01
The never-ending quest to improve the security of digital information combined with recent improvements in hardware technology has caused the field of random number generation to undergo a fundamental shift from relying solely on pseudo-random algorithms to employing optical entropy sources. Despite these significant advances on the hardware side, commonly used statistical measures and evaluation practices remain ill-suited to understand or quantify the optical entropy that underlies physical random number generation. We review the state of the art in the evaluation of optical random number generation and recommend a new paradigm: quantifying entropy generation and understanding the physical limits of the optical sources of randomness. In order to do this, we advocate for the separation of the physical entropy source from deterministic post-processing in the evaluation of random number generators and for the explicit consideration of the impact of the measurement and digitization process on the rate of entropy production. We present the Cohen-Procaccia estimate of the entropy rate h (𝜖 ,τ ) as one way to do this. In order to provide an illustration of our recommendations, we apply the Cohen-Procaccia estimate as well as the entropy estimates from the new NIST draft standards for physical random number generators to evaluate and compare three common optical entropy sources: single photon time-of-arrival detection, chaotic lasers, and amplified spontaneous emission.
A novel quantum random number generation algorithm used by smartphone camera
NASA Astrophysics Data System (ADS)
Wu, Nan; Wang, Kun; Hu, Haixing; Song, Fangmin; Li, Xiangdong
2015-05-01
We study an efficient algorithm to extract quantum random numbers (QRN) from the raw data obtained by charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) based sensors, like a camera used in a commercial smartphone. Based on NIST statistical test for random number generators, the proposed algorithm has a high QRN generation rate and high statistical randomness. This algorithm provides a kind of simple, low-priced and reliable devices as a QRN generator for quantum key distribution (QKD) or other cryptographic applications.
A Comparison of Three Random Number Generators for Aircraft Dynamic Modeling Applications
NASA Technical Reports Server (NTRS)
Grauer, Jared A.
2017-01-01
Three random number generators, which produce Gaussian white noise sequences, were compared to assess their suitability in aircraft dynamic modeling applications. The first generator considered was the MATLAB (registered) implementation of the Mersenne-Twister algorithm. The second generator was a website called Random.org, which processes atmospheric noise measured using radios to create the random numbers. The third generator was based on synthesis of the Fourier series, where the random number sequences are constructed from prescribed amplitude and phase spectra. A total of 200 sequences, each having 601 random numbers, for each generator were collected and analyzed in terms of the mean, variance, normality, autocorrelation, and power spectral density. These sequences were then applied to two problems in aircraft dynamic modeling, namely estimating stability and control derivatives from simulated onboard sensor data, and simulating flight in atmospheric turbulence. In general, each random number generator had good performance and is well-suited for aircraft dynamic modeling applications. Specific strengths and weaknesses of each generator are discussed. For Monte Carlo simulation, the Fourier synthesis method is recommended because it most accurately and consistently approximated Gaussian white noise and can be implemented with reasonable computational effort.
Quantum random number generation using an on-chip plasmonic beamsplitter
NASA Astrophysics Data System (ADS)
Francis, Jason T.; Zhang, Xia; Özdemir, Şahin K.; Tame, Mark
2017-09-01
We report an experimental realisation of a quantum random number generator using a plasmonic beamsplitter. Free-space single photons are converted into propagating single surface plasmon polaritons on a gold stripe waveguide via a grating. The surface plasmons are then guided to a region where they are scattered into one of two possible outputs. The presence of a plasmonic excitation in a given output determines the value of a random bit generated from the quantum scattering process. Using a stream of single surface plasmons injected into the beamsplitter we achieve a quantum random number generation rate of 2.37 Mbits s-1 even in the presence of loss. We characterise the quality of the random number sequence generated, finding it to be comparable to sequences from other quantum photonic-based devices. The compact nature of our nanophotonic device makes it suitable for tight integration in on-chip applications, such as in quantum computing and communication schemes.
Towse, John N; Loetscher, Tobias; Brugger, Peter
2014-01-01
We investigate the number preferences of children and adults when generating random digit sequences. Previous research has shown convincingly that adults prefer smaller numbers when randomly choosing between responses 1-6. We analyze randomization choices made by both children and adults, considering a range of experimental studies and task configurations. Children - most of whom are between 8 and 11~years - show a preference for relatively large numbers when choosing numbers 1-10. Adults show a preference for small numbers with the same response set. We report a modest association between children's age and numerical bias. However, children also exhibit a small number bias with a smaller response set available, and they show a preference specifically for the numbers 1-3 across many datasets. We argue that number space demonstrates both continuities (numbers 1-3 have a distinct status) and change (a developmentally emerging bias toward the left side of representational space or lower numbers).
Efficient pseudo-random number generation for monte-carlo simulations using graphic processors
NASA Astrophysics Data System (ADS)
Mohanty, Siddhant; Mohanty, A. K.; Carminati, F.
2012-06-01
A hybrid approach based on the combination of three Tausworthe generators and one linear congruential generator for pseudo random number generation for GPU programing as suggested in NVIDIA-CUDA library has been used for MONTE-CARLO sampling. On each GPU thread, a random seed is generated on fly in a simple way using the quick and dirty algorithm where mod operation is not performed explicitly due to unsigned integer overflow. Using this hybrid generator, multivariate correlated sampling based on alias technique has been carried out using both CUDA and OpenCL languages.
The generation of 68 Gbps quantum random number by measuring laser phase fluctuations
Nie, You-Qi; Liu, Yang; Zhang, Jun Pan, Jian-Wei; Huang, Leilei; Payne, Frank
2015-06-15
The speed of a quantum random number generator is essential for practical applications, such as high-speed quantum key distribution systems. Here, we push the speed of a quantum random number generator to 68 Gbps by operating a laser around its threshold level. To achieve the rate, not only high-speed photodetector and high sampling rate are needed but also a very stable interferometer is required. A practical interferometer with active feedback instead of common temperature control is developed to meet the requirement of stability. Phase fluctuations of the laser are measured by the interferometer with a photodetector and then digitalized to raw random numbers with a rate of 80 Gbps. The min-entropy of the raw data is evaluated by modeling the system and is used to quantify the quantum randomness of the raw data. The bias of the raw data caused by other signals, such as classical and detection noises, can be removed by Toeplitz-matrix hashing randomness extraction. The final random numbers can pass through the standard randomness tests. Our demonstration shows that high-speed quantum random number generators are ready for practical usage.
The generation of 68 Gbps quantum random number by measuring laser phase fluctuations.
Nie, You-Qi; Huang, Leilei; Liu, Yang; Payne, Frank; Zhang, Jun; Pan, Jian-Wei
2015-06-01
The speed of a quantum random number generator is essential for practical applications, such as high-speed quantum key distribution systems. Here, we push the speed of a quantum random number generator to 68 Gbps by operating a laser around its threshold level. To achieve the rate, not only high-speed photodetector and high sampling rate are needed but also a very stable interferometer is required. A practical interferometer with active feedback instead of common temperature control is developed to meet the requirement of stability. Phase fluctuations of the laser are measured by the interferometer with a photodetector and then digitalized to raw random numbers with a rate of 80 Gbps. The min-entropy of the raw data is evaluated by modeling the system and is used to quantify the quantum randomness of the raw data. The bias of the raw data caused by other signals, such as classical and detection noises, can be removed by Toeplitz-matrix hashing randomness extraction. The final random numbers can pass through the standard randomness tests. Our demonstration shows that high-speed quantum random number generators are ready for practical usage.
The generation of 68 Gbps quantum random number by measuring laser phase fluctuations
NASA Astrophysics Data System (ADS)
Nie, You-Qi; Huang, Leilei; Liu, Yang; Payne, Frank; Zhang, Jun; Pan, Jian-Wei
2015-06-01
The speed of a quantum random number generator is essential for practical applications, such as high-speed quantum key distribution systems. Here, we push the speed of a quantum random number generator to 68 Gbps by operating a laser around its threshold level. To achieve the rate, not only high-speed photodetector and high sampling rate are needed but also a very stable interferometer is required. A practical interferometer with active feedback instead of common temperature control is developed to meet the requirement of stability. Phase fluctuations of the laser are measured by the interferometer with a photodetector and then digitalized to raw random numbers with a rate of 80 Gbps. The min-entropy of the raw data is evaluated by modeling the system and is used to quantify the quantum randomness of the raw data. The bias of the raw data caused by other signals, such as classical and detection noises, can be removed by Toeplitz-matrix hashing randomness extraction. The final random numbers can pass through the standard randomness tests. Our demonstration shows that high-speed quantum random number generators are ready for practical usage.
Fault-tolerant quantum random-number generator certified by Majorana fermions
NASA Astrophysics Data System (ADS)
Deng, Dong-Ling; Duan, Lu-Ming
2013-07-01
Braiding of Majorana fermions gives accurate topological quantum operations that are intrinsically robust to noise and imperfection, providing a natural method to realize fault-tolerant quantum information processing. Unfortunately, it is known that braiding of Majorana fermions is not sufficient for the implementation of universal quantum computation. Here we show that topological manipulation of Majorana fermions provides the full set of operations required to generate random numbers by way of quantum mechanics and to certify its genuine randomness through violation of a multipartite Bell inequality. The result opens a perspective to apply Majorana fermions for the robust generation of certified random numbers, which has important applications in cryptography and other related areas.
Loss-tolerant measurement-device-independent quantum random number generation
NASA Astrophysics Data System (ADS)
Cao, Zhu; Zhou, Hongyi; Ma, Xiongfeng
2015-12-01
Quantum random number generators (QRNGs) output genuine random numbers based upon the uncertainty principle. A QRNG contains two parts in general—a randomness source and a readout detector. How to remove detector imperfections has been one of the most important questions in practical randomness generation. We propose a simple solution, measurement-device-independent QRNG, which not only removes all detector side channels but is robust against losses. In contrast to previous fully device-independent QRNGs, our scheme does not require high detector efficiency or nonlocality tests. Simulations show that our protocol can be implemented efficiently with a practical coherent state laser and other standard optical components. The security analysis of our QRNG consists mainly of two parts: measurement tomography and randomness quantification, where several new techniques are developed to characterize the randomness associated with a positive-operator valued measure.
A robust approach to the generation of high-quality random numbers
NASA Astrophysics Data System (ADS)
Bisadi, Zahra; Fontana, Giorgio; Moser, Enrico; Pucker, Georg; Pavesi, Lorenzo
2016-10-01
A random number generation approach comprising a silicon nanocrystals LED (Si-NCs LED), silicon single photon avalanche photodiode (Si SPAD) and a field-programmable gate array (FPGA) is introduced. The Si-NCs LED is the source of entropy with photon emission in the visible range detectable by silicon detectors allowing the fabrication of an all-silicon-based device. The proposed quantum random number generator (QRNG) is robust against variations of the internal and external parameters such as aging of the components, changing temperature, the ambient interferences and the silicon detector artifacts. The raw data show high quality of randomness and passed all the statistical tests in National Institute of Standards and Technology (NIST) tests suite without the application of a post-processing algorithm. The efficiency of random number generation is 4-bits per detected photon.
Note: Fully integrated 3.2 Gbps quantum random number generator with real-time extraction
Zhang, Xiao-Guang; Nie, You-Qi; Liang, Hao; Zhang, Jun Pan, Jian-Wei; Zhou, Hongyi; Ma, Xiongfeng
2016-07-15
We present a real-time and fully integrated quantum random number generator (QRNG) by measuring laser phase fluctuations. The QRNG scheme based on laser phase fluctuations is featured for its capability of generating ultra-high-speed random numbers. However, the speed bottleneck of a practical QRNG lies on the limited speed of randomness extraction. To close the gap between the fast randomness generation and the slow post-processing, we propose a pipeline extraction algorithm based on Toeplitz matrix hashing and implement it in a high-speed field-programmable gate array. Further, all the QRNG components are integrated into a module, including a compact and actively stabilized interferometer, high-speed data acquisition, and real-time data post-processing and transmission. The final generation rate of the QRNG module with real-time extraction can reach 3.2 Gbps.
Note: Fully integrated 3.2 Gbps quantum random number generator with real-time extraction.
Zhang, Xiao-Guang; Nie, You-Qi; Zhou, Hongyi; Liang, Hao; Ma, Xiongfeng; Zhang, Jun; Pan, Jian-Wei
2016-07-01
We present a real-time and fully integrated quantum random number generator (QRNG) by measuring laser phase fluctuations. The QRNG scheme based on laser phase fluctuations is featured for its capability of generating ultra-high-speed random numbers. However, the speed bottleneck of a practical QRNG lies on the limited speed of randomness extraction. To close the gap between the fast randomness generation and the slow post-processing, we propose a pipeline extraction algorithm based on Toeplitz matrix hashing and implement it in a high-speed field-programmable gate array. Further, all the QRNG components are integrated into a module, including a compact and actively stabilized interferometer, high-speed data acquisition, and real-time data post-processing and transmission. The final generation rate of the QRNG module with real-time extraction can reach 3.2 Gbps.
Note: Fully integrated 3.2 Gbps quantum random number generator with real-time extraction
NASA Astrophysics Data System (ADS)
Zhang, Xiao-Guang; Nie, You-Qi; Zhou, Hongyi; Liang, Hao; Ma, Xiongfeng; Zhang, Jun; Pan, Jian-Wei
2016-07-01
We present a real-time and fully integrated quantum random number generator (QRNG) by measuring laser phase fluctuations. The QRNG scheme based on laser phase fluctuations is featured for its capability of generating ultra-high-speed random numbers. However, the speed bottleneck of a practical QRNG lies on the limited speed of randomness extraction. To close the gap between the fast randomness generation and the slow post-processing, we propose a pipeline extraction algorithm based on Toeplitz matrix hashing and implement it in a high-speed field-programmable gate array. Further, all the QRNG components are integrated into a module, including a compact and actively stabilized interferometer, high-speed data acquisition, and real-time data post-processing and transmission. The final generation rate of the QRNG module with real-time extraction can reach 3.2 Gbps.
Scope of Various Random Number Generators in Ant System Approach for TSP
NASA Technical Reports Server (NTRS)
Sen, S. K.; Shaykhian, Gholam Ali
2007-01-01
Experimented on heuristic, based on an ant system approach for traveling Salesman problem, are several quasi and pseudo-random number generators. This experiment is to explore if any particular generator is most desirable. Such an experiment on large samples has the potential to rank the performance of the generators for the foregoing heuristic. This is just to seek an answer to the controversial performance ranking of the generators in probabilistic/statically sense.
Münte, Thomas F; Joppich, Gregor; Däuper, Jan; Schrader, Christoph; Dengler, Reinhard; Heldmann, Marcus
2015-01-01
The generation of random sequences is considered to tax executive functions and has been reported to be impaired in Parkinson's disease (PD) previously. To assess the neurophysiological markers of random number generation in PD. Event-related potentials (ERP) were recorded in 12 PD patients and 12 age-matched normal controls (NC) while either engaging in random number generation (RNG) by pressing the number keys on a computer keyboard in a random sequence or in ordered number generation (ONG) necessitating key presses in the canonical order. Key presses were paced by an external auditory stimulus at a rate of 1 tone every 1800 ms. As a secondary task subjects had to monitor the tone-sequence for a particular target tone to which the number "0" key had to be pressed. This target tone occurred randomly and infrequently, thus creating a secondary oddball task. Behaviorally, PD patients showed an increased tendency to count in steps of one as well as a tendency towards repetition avoidance. Electrophysiologically, the amplitude of the P3 component of the ERP to the target tone of the secondary task was reduced during RNG in PD but not in NC. The behavioral findings indicate less random behavior in PD while the ERP findings suggest that this impairment comes about, because attentional resources are depleted in PD.
25 CFR 547.14 - What are the minimum technical standards for electronic random number generation?
Code of Federal Regulations, 2012 CFR
2012-04-01
... CLASS II GAMES § 547.14 What are the minimum technical standards for electronic random number generation... rules of the game. For example, if a bingo game with 75 objects with numbers or other designations has a... serial correlation (outcomes shall be independent from the previous game); and (x) Test on...
25 CFR 547.14 - What are the minimum technical standards for electronic random number generation?
Code of Federal Regulations, 2011 CFR
2011-04-01
... CLASS II GAMES § 547.14 What are the minimum technical standards for electronic random number generation... rules of the game. For example, if a bingo game with 75 objects with numbers or other designations has a... serial correlation (outcomes shall be independent from the previous game); and (x) Test on...
Practical quantum random number generator based on measuring the shot noise of vacuum states
Shen Yong; Zou Hongxin; Tian Liang
2010-06-15
The shot noise of vacuum states is a kind of quantum noise and is totally random. In this paper a nondeterministic random number generation scheme based on measuring the shot noise of vacuum states is presented and experimentally demonstrated. We use a homodyne detector to measure the shot noise of vacuum states. Considering that the frequency bandwidth of our detector is limited, we derive the optimal sampling rate so that sampling points have the least correlation with each other. We also choose a method to extract random numbers from sampling values, and prove that the influence of classical noise can be avoided with this method so that the detector does not have to be shot-noise limited. The random numbers generated with this scheme have passed ent and diehard tests.
Practical quantum random number generator based on measuring the shot noise of vacuum states
NASA Astrophysics Data System (ADS)
Shen, Yong; Tian, Liang; Zou, Hongxin
2010-06-01
The shot noise of vacuum states is a kind of quantum noise and is totally random. In this paper a nondeterministic random number generation scheme based on measuring the shot noise of vacuum states is presented and experimentally demonstrated. We use a homodyne detector to measure the shot noise of vacuum states. Considering that the frequency bandwidth of our detector is limited, we derive the optimal sampling rate so that sampling points have the least correlation with each other. We also choose a method to extract random numbers from sampling values, and prove that the influence of classical noise can be avoided with this method so that the detector does not have to be shot-noise limited. The random numbers generated with this scheme have passed ent and diehard tests.
Direct generation of all-optical random numbers from optical pulse amplitude chaos.
Li, Pu; Wang, Yun-Cai; Wang, An-Bang; Yang, Ling-Zhen; Zhang, Ming-Jiang; Zhang, Jian-Zhong
2012-02-13
We propose and theoretically demonstrate an all-optical method for directly generating all-optical random numbers from pulse amplitude chaos produced by a mode-locked fiber ring laser. Under an appropriate pump intensity, the mode-locked laser can experience a quasi-periodic route to chaos. Such a chaos consists of a stream of pulses with a fixed repetition frequency but random intensities. In this method, we do not require sampling procedure and external triggered clocks but directly quantize the chaotic pulses stream into random number sequence via an all-optical flip-flop. Moreover, our simulation results show that the pulse amplitude chaos has no periodicity and possesses a highly symmetric distribution of amplitude. Thus, in theory, the obtained random number sequence without post-processing has a high-quality randomness verified by industry-standard statistical tests.
An efficient algorithm for generating random number pairs drawn from a bivariate normal distribution
NASA Technical Reports Server (NTRS)
Campbell, C. W.
1983-01-01
An efficient algorithm for generating random number pairs from a bivariate normal distribution was developed. Any desired value of the two means, two standard deviations, and correlation coefficient can be selected. Theoretically the technique is exact and in practice its accuracy is limited only by the quality of the uniform distribution random number generator, inaccuracies in computer function evaluation, and arithmetic. A FORTRAN routine was written to check the algorithm and good accuracy was obtained. Some small errors in the correlation coefficient were observed to vary in a surprisingly regular manner. A simple model was developed which explained the qualities aspects of the errors.
NASA Astrophysics Data System (ADS)
Tong, Qiaoling; Zou, Xuecheng; Tong, Hengqing
2009-10-01
Radio Frequency Identification (RFID) technology has been widely used in the image recognition system. However, the feature of the RFID system may bring out security threatens. In this paper, we analyze the existing RFID authentication protocols and state an infinite dimension pseudo random number generator to strengthen the protocol security. Then an authentication protocol based on infinite dimension pseudo random number generator is proposed. Compared to the traditional protocols, our method could resist various attack approaches, and protect the tag information and the location privacy of the tag holder efficiently.
NASA Astrophysics Data System (ADS)
Brask, Jonatan Bohr; Martin, Anthony; Esposito, William; Houlmann, Raphael; Bowles, Joseph; Zbinden, Hugo; Brunner, Nicolas
2017-05-01
An approach to quantum random number generation based on unambiguous quantum state discrimination is developed. We consider a prepare-and-measure protocol, where two nonorthogonal quantum states can be prepared, and a measurement device aims at unambiguously discriminating between them. Because the states are nonorthogonal, this necessarily leads to a minimal rate of inconclusive events whose occurrence must be genuinely random and which provide the randomness source that we exploit. Our protocol is semi-device-independent in the sense that the output entropy can be lower bounded based on experimental data and a few general assumptions about the setup alone. It is also practically relevant, which we demonstrate by realizing a simple optical implementation, achieving rates of 16.5 Mbits /s . Combining ease of implementation, a high rate, and a real-time entropy estimation, our protocol represents a promising approach intermediate between fully device-independent protocols and commercial quantum random number generators.
640-Gbit/s fast physical random number generation using a broadband chaotic semiconductor laser
Zhang, Limeng; Pan, Biwei; Chen, Guangcan; Guo, Lu; Lu, Dan; Zhao, Lingjuan; Wang, Wei
2017-01-01
An ultra-fast physical random number generator is demonstrated utilizing a photonic integrated device based broadband chaotic source with a simple post data processing method. The compact chaotic source is implemented by using a monolithic integrated dual-mode amplified feedback laser (AFL) with self-injection, where a robust chaotic signal with RF frequency coverage of above 50 GHz and flatness of ±3.6 dB is generated. By using 4-least significant bits (LSBs) retaining from the 8-bit digitization of the chaotic waveform, random sequences with a bit-rate up to 640 Gbit/s (160 GS/s × 4 bits) are realized. The generated random bits have passed each of the fifteen NIST statistics tests (NIST SP800-22), indicating its randomness for practical applications. PMID:28374860
640-Gbit/s fast physical random number generation using a broadband chaotic semiconductor laser.
Zhang, Limeng; Pan, Biwei; Chen, Guangcan; Guo, Lu; Lu, Dan; Zhao, Lingjuan; Wang, Wei
2017-04-04
An ultra-fast physical random number generator is demonstrated utilizing a photonic integrated device based broadband chaotic source with a simple post data processing method. The compact chaotic source is implemented by using a monolithic integrated dual-mode amplified feedback laser (AFL) with self-injection, where a robust chaotic signal with RF frequency coverage of above 50 GHz and flatness of ±3.6 dB is generated. By using 4-least significant bits (LSBs) retaining from the 8-bit digitization of the chaotic waveform, random sequences with a bit-rate up to 640 Gbit/s (160 GS/s × 4 bits) are realized. The generated random bits have passed each of the fifteen NIST statistics tests (NIST SP800-22), indicating its randomness for practical applications.
640-Gbit/s fast physical random number generation using a broadband chaotic semiconductor laser
NASA Astrophysics Data System (ADS)
Zhang, Limeng; Pan, Biwei; Chen, Guangcan; Guo, Lu; Lu, Dan; Zhao, Lingjuan; Wang, Wei
2017-04-01
An ultra-fast physical random number generator is demonstrated utilizing a photonic integrated device based broadband chaotic source with a simple post data processing method. The compact chaotic source is implemented by using a monolithic integrated dual-mode amplified feedback laser (AFL) with self-injection, where a robust chaotic signal with RF frequency coverage of above 50 GHz and flatness of ±3.6 dB is generated. By using 4-least significant bits (LSBs) retaining from the 8-bit digitization of the chaotic waveform, random sequences with a bit-rate up to 640 Gbit/s (160 GS/s × 4 bits) are realized. The generated random bits have passed each of the fifteen NIST statistics tests (NIST SP800-22), indicating its randomness for practical applications.
Toward DNA-based Security Circuitry: First Step - Random Number Generation.
Bogard, Christy M; Arazi, Benjamin; Rouchka, Eric C
2008-08-10
DNA-based circuit design is an area of research in which traditional silicon-based technologies are replaced by naturally occurring phenomena taken from biochemistry and molecular biology. Our team investigates the implications of DNA-based circuit design in serving security applications. As an initial step we develop a random number generation circuitry. A novel prototype schema employs solid-phase synthesis of oligonucleotides for random construction of DNA sequences. Temporary storage and retrieval is achieved through plasmid vectors.
Scope of Various Random Number Generators in ant System Approach for TSP
NASA Technical Reports Server (NTRS)
Sen, S. K.; Shaykhian, Gholam Ali
2007-01-01
Experimented on heuristic, based on an ant system approach for traveling salesman problem, are several quasi- and pseudo-random number generators. This experiment is to explore if any particular generator is most desirable. Such an experiment on large samples has the potential to rank the performance of the generators for the foregoing heuristic. This is mainly to seek an answer to the controversial issue "which generator is the best in terms of quality of the result (accuracy) as well as cost of producing the result (time/computational complexity) in a probabilistic/statistical sense."
Scope of Various Random Number Generators in ant System Approach for TSP
NASA Technical Reports Server (NTRS)
Sen, S. K.; Shaykhian, Gholam Ali
2007-01-01
Experimented on heuristic, based on an ant system approach for traveling salesman problem, are several quasi- and pseudo-random number generators. This experiment is to explore if any particular generator is most desirable. Such an experiment on large samples has the potential to rank the performance of the generators for the foregoing heuristic. This is mainly to seek an answer to the controversial issue "which generator is the best in terms of quality of the result (accuracy) as well as cost of producing the result (time/computational complexity) in a probabilistic/statistical sense."
Minimalist design of a robust real-time quantum random number generator
NASA Astrophysics Data System (ADS)
Kravtsov, K. S.; Radchenko, I. V.; Kulik, S. P.; Molotkov, S. N.
2015-08-01
We present a simple and robust construction of a real-time quantum random number generator (QRNG). Our minimalist approach ensures stable operation of the device as well as its simple and straightforward hardware implementation as a stand-alone module. As a source of randomness the device uses measurements of time intervals between clicks of a single-photon detector. The obtained raw sequence is then filtered and processed by a deterministic randomness extractor, which is realized as a look-up table. This enables high speed on-the-fly processing without the need of extensive computations. The overall performance of the device is around 1 random bit per detector click, resulting in 1.2 Mbit/s generation rate in our implementation.
A robust random number generator based on differential comparison of chaotic laser signals.
Zhang, Jianzhong; Wang, Yuncai; Liu, Ming; Xue, Lugang; Li, Pu; Wang, Anbang; Zhang, Mingjiang
2012-03-26
We experimentally realize a robust real-time random number generator by differentially comparing the signal from a chaotic semiconductor laser and its delayed signal through a 1-bit analog-to-digital converter. The probability density distribution of the output chaotic signal based on the differential comparison method possesses an extremely small coefficient of Pearson's median skewness (1.5 × 10⁻⁶), which can yield a balanced random sequence much easily than the previously reported method that compares the signal from the chaotic laser with a certain threshold value. Moveover, we experimently demonstrate that our method can stably generate good random numbers at rates of 1.44 Gbit/s with excellent immunity from external perturbations while the previously reported method fails.
Numerical analysis of ultrafast physical random number generator using dual-channel optical chaos
NASA Astrophysics Data System (ADS)
Elsonbaty, Amr; Hegazy, Salem F.; Obayya, Salah S. A.
2016-09-01
Fast physical random number generators (PRNGs) are essential elements in the development of many modern applications. We numerically demonstrate an extraction scheme to establish an ultrafast PRNG using dual-channel optical-chaos source. Simultaneous suppression of time-delay signature in all observables of the output is verified using autocorrelation-function method. The proposed technique compares the level of the chaotic signal at time t with M levels of its delayed version. The comparators [1-bit analog-to-digital converters (ADCs)] are triggered using a clock subject to an incremental delay. All the delays of the chaotic signal before the ADCs and the relative delays of the clock are mutually incommensurable. The outputs of the ADCs are then combined using parity-check logic to produce physically true random numbers. The randomness quality of the generated random bits is evaluated by the statistical tests of National Institute of Standards and Technology Special Publication 800-22. The results verify that all tests are passed from M=1 to M=39 at sampling rate up to 34.5 GHz, which indicates that the maximum generation rate of random bits is 2.691 Tb/s without employing any preprocessing techniques. This rate, to the best of our knowledge, is higher than any previously reported PRNG.
Phillips, Carolyn L.; Anderson, Joshua A.; Glotzer, Sharon C.
2011-08-10
Highlights: {yields} Molecular Dynamics codes implemented on GPUs have achieved two-order of magnitude computational accelerations. {yields} Brownian Dynamics and Dissipative Particle Dynamics simulations require a large number of random numbers per time step. {yields} We introduce a method for generating small batches of pseudorandom numbers distributed over many threads of calculations. {yields} With this method, Dissipative Particle Dynamics is implemented on a GPU device without requiring thread-to-thread communication. - Abstract: Brownian Dynamics (BD), also known as Langevin Dynamics, and Dissipative Particle Dynamics (DPD) are implicit solvent methods commonly used in models of soft matter and biomolecular systems. The interaction of the numerous solvent particles with larger particles is coarse-grained as a Langevin thermostat is applied to individual particles or to particle pairs. The Langevin thermostat requires a pseudo-random number generator (PRNG) to generate the stochastic force applied to each particle or pair of neighboring particles during each time step in the integration of Newton's equations of motion. In a Single-Instruction-Multiple-Thread (SIMT) GPU parallel computing environment, small batches of random numbers must be generated over thousands of threads and millions of kernel calls. In this communication we introduce a one-PRNG-per-kernel-call-per-thread scheme, in which a micro-stream of pseudorandom numbers is generated in each thread and kernel call. These high quality, statistically robust micro-streams require no global memory for state storage, are more computationally efficient than other PRNG schemes in memory-bound kernels, and uniquely enable the DPD simulation method without requiring communication between threads.
RANDOM: A Computer Program for Evaluating Pseudo-Uniform RANDOM Number Generators.
1982-08-01
correlation employed in RANDOM is taken from Wald and Wolfowitz (1943) and is performed using both the circular and noncircular definitions. The theory behind...Addison-Wesley, 1962). Wald , A. and J. Wolfowitz , "An Exact Test for Randomness in the Non-Parametric Case Based on Serial Correlation," Annals of...measures the interdependence between these two variables. If p = q, the covariance between R and Rq is equivalent to the variance of Rp. Wolfowitz (1944
Application of random number generators in genetic algorithms to improve rainfall-runoff modelling
NASA Astrophysics Data System (ADS)
Chlumecký, Martin; Buchtele, Josef; Richta, Karel
2017-10-01
The efficient calibration of rainfall-runoff models is a difficult issue, even for experienced hydrologists. Therefore, fast and high-quality model calibration is a valuable improvement. This paper describes a novel methodology and software for the optimisation of a rainfall-runoff modelling using a genetic algorithm (GA) with a newly prepared concept of a random number generator (HRNG), which is the core of the optimisation. The GA estimates model parameters using evolutionary principles, which requires a quality number generator. The new HRNG generates random numbers based on hydrological information and it provides better numbers compared to pure software generators. The GA enhances the model calibration very well and the goal is to optimise the calibration of the model with a minimum of user interaction. This article focuses on improving the internal structure of the GA, which is shielded from the user. The results that we obtained indicate that the HRNG provides a stable trend in the output quality of the model, despite various configurations of the GA. In contrast to previous research, the HRNG speeds up the calibration of the model and offers an improvement of rainfall-runoff modelling.
40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sample selection by random number... Â§ 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square... area created in accordance with paragraph (a) of this section, select two random numbers: one each for...
ERIC Educational Resources Information Center
Boonsathorn, Wasita; Charoen, Danuvasin; Dryver, Arthur L.
2014-01-01
E-Learning brings access to a powerful but often overlooked teaching tool: random number generation. Using random number generation, a practically infinite number of quantitative problem-solution sets can be created. In addition, within the e-learning context, in the spirit of the mastery of learning, it is possible to assign online quantitative…
ERIC Educational Resources Information Center
Boonsathorn, Wasita; Charoen, Danuvasin; Dryver, Arthur L.
2014-01-01
E-Learning brings access to a powerful but often overlooked teaching tool: random number generation. Using random number generation, a practically infinite number of quantitative problem-solution sets can be created. In addition, within the e-learning context, in the spirit of the mastery of learning, it is possible to assign online quantitative…
Complexity and properties of a multidimensional Cat-Hadamard map for pseudo random number generation
NASA Astrophysics Data System (ADS)
Kim Hue, Ta Thi; Hoang, Thang Manh
2017-01-01
This paper presents a novel method to extend the Cat map from 2-dimension to higher dimension using the fast pseudo Hadamard Transform, and the resulted maps are called Cat-Hadamard maps. The complexity and properties of Cat-Hadamard maps are investigated under the point of view for cryptographic applications. In addition, we propose a method for constructing a pseudo random number generator using a novel design concept of the high dimensional Cat map. The simulation results show that the proposed generator fulfilled all the statistic tests of the NIST SP 800-90 A.
Complexity and properties of a multidimensional Cat-Hadamard map for pseudo random number generation
NASA Astrophysics Data System (ADS)
Kim Hue, Ta Thi; Hoang, Thang Manh
2017-07-01
This paper presents a novel method to extend the Cat map from 2-dimension to higher dimension using the fast pseudo Hadamard Transform, and the resulted maps are called Cat-Hadamard maps. The complexity and properties of Cat-Hadamard maps are investigated under the point of view for cryptographic applications. In addition, we propose a method for constructing a pseudo random number generator using a novel design concept of the high dimensional Cat map. The simulation results show that the proposed generator fulfilled all the statistic tests of the NIST SP 800-90 A.
Zhmurov, A; Rybnikov, K; Kholodov, Y; Barsegov, V
2011-05-12
The use of graphics processing units (GPUs) in simulation applications offers a significant speed gain as compared to computations on central processing units (CPUs). Many simulation methods require a large number of independent random variables generated at each step. We present two approaches for implementation of random number generators (RNGs) on a GPU. In the one-RNG-per-thread approach, one RNG produces a stream of random numbers in each thread of execution, whereas the one-RNG-for-all-threads method builds on the ability of different threads to communicate, thus, sharing random seeds across an entire GPU device. We used these approaches to implement Ran2, Hybrid Taus, and Lagged Fibonacci algorithms on a GPU. We profiled the performance of these generators in terms of the computational time, memory usage, and the speedup factor (CPU time/GPU time). These generators have been incorporated into the program for Langevin simulations of biomolecules fully implemented on the GPU. The ∼250-fold computational speedup on the GPU allowed us to carry out single-molecule dynamic force measurements in silico to explore the mechanical properties of the bacteriophage HK97 in the experimental subsecond time scale. We found that the nanomechanical response of HK97 depends on the conditions of force application, including the rate of change and geometry of the mechanical perturbation. Hence, using the GPU-based implementation of RNGs, presented here, in conjunction with Langevin simulations, makes it possible to directly compare the results of dynamic force measurements in vitro and in silico.
Yu, Aifang; Chen, Xiangyu; Cui, Haotian; Chen, Libo; Luo, Jianjun; Tang, Wei; Peng, Mingzeng; Zhang, Yang; Zhai, Junyi; Wang, Zhong Lin
2016-12-27
Modern cryptography increasingly employs random numbers generated from physical sources in lieu of conventional software-based pseudorandom numbers, primarily owing to the great demand of unpredictable, indecipherable cryptographic keys from true random numbers for information security. Thus, far, the sole demonstration of true random numbers has been generated through thermal noise and/or quantum effects, which suffers from expensive and complex equipment. In this paper, we demonstrate a method for self-powered creation of true random numbers by using triboelectric technology to collect random signals from nature. This random number generator based on coupled triboelectric and electrostatic induction effects at the liquid-dielectric interface includes an elaborately designed triboelectric generator (TENG) with an irregular grating structure, an electronic-optical device, and an optical-electronic device. The random characteristics of raindrops are harvested through TENG and consequently transformed and converted by electronic-optical device and an optical-electronic device with a nonlinear characteristic. The cooperation of the mechanical, electrical, and optical signals ensures that the generator possesses complex nonlinear input-output behavior and contributes to increased randomness. The random number sequences are deduced from final electrical signals received by an optical-electronic device using a familiar algorithm. These obtained random number sequences exhibit good statistical characteristics, unpredictability, and unrepeatability. Our study supplies a simple, practical, and effective method to generate true random numbers, which can be widely used in cryptographic protocols, digital signatures, authentication, identification, and other information security fields.
NASA Astrophysics Data System (ADS)
Rangarajan, Nikhil; Parthasarathy, Arun; Rakheja, Shaloo
2017-06-01
In this paper, we propose a spin-based true random number generator (TRNG) that uses the inherent stochasticity in nanomagnets as the source of entropy. In contrast to previous works on spin-based TRNGs, we focus on the precessional switching strategy in nanomagnets to generate a truly random sequence. Using the NIST SP 800-22 test suite for randomness, we demonstrate that the output of the proposed TRNG circuit is statistically random with 99% confidence levels. The effects of process and temperature variability on the device are studied and shown to have no effect on the quality of randomness of the device. To benchmark the performance of the TRNG in terms of area, throughput, and power, we use SPICE (Simulation Program with Integrated Circuit Emphasis)-based models of the nanomagnet and combine them with CMOS device models at the 45 nm technology node. The throughput, power, and area footprints of the proposed TRNG are shown to be better than those of existing state-of-the-art TRNGs. We identify the optimal material and geometrical parameters of the nanomagnet to minimize the energy per bit at a given throughput of the TRNG circuit. Our results provide insights into the device-level modifications that can yield significant system-level improvements. Overall, the proposed spin-based TRNG circuit shows significant robustness, reliability, and fidelity and, therefore, has a potential for on-chip implementation.
An On-Demand Optical Quantum Random Number Generator with In-Future Action and Ultra-Fast Response
Stipčević, Mario; Ursin, Rupert
2015-01-01
Random numbers are essential for our modern information based society e.g. in cryptography. Unlike frequently used pseudo-random generators, physical random number generators do not depend on complex algorithms but rather on a physicsal process to provide true randomness. Quantum random number generators (QRNG) do rely on a process, wich can be described by a probabilistic theory only, even in principle. Here we present a conceptualy simple implementation, which offers a 100% efficiency of producing a random bit upon a request and simultaneously exhibits an ultra low latency. A careful technical and statistical analysis demonstrates its robustness against imperfections of the actual implemented technology and enables to quickly estimate randomness of very long sequences. Generated random numbers pass standard statistical tests without any post-processing. The setup described, as well as the theory presented here, demonstrate the maturity and overall understanding of the technology. PMID:26057576
An On-Demand Optical Quantum Random Number Generator with In-Future Action and Ultra-Fast Response.
Stipčević, Mario; Ursin, Rupert
2015-06-09
Random numbers are essential for our modern information based society e.g. in cryptography. Unlike frequently used pseudo-random generators, physical random number generators do not depend on complex algorithms but rather on a physical process to provide true randomness. Quantum random number generators (QRNG) do rely on a process, which can be described by a probabilistic theory only, even in principle. Here we present a conceptually simple implementation, which offers a 100% efficiency of producing a random bit upon a request and simultaneously exhibits an ultra low latency. A careful technical and statistical analysis demonstrates its robustness against imperfections of the actual implemented technology and enables to quickly estimate randomness of very long sequences. Generated random numbers pass standard statistical tests without any post-processing. The setup described, as well as the theory presented here, demonstrate the maturity and overall understanding of the technology.
All-optical random number generation using highly nonlinear fibers by numerical simulation
NASA Astrophysics Data System (ADS)
Wang, Juanfen; Liang, Junqiang; Li, Pu; Yang, Lingzhen; Wang, Yuncai
2014-06-01
A new scheme of all-optical random number generation based on the nonlinear effects in highly nonlinear fibers (HNLF) is proposed. The scheme is comprised of ultra-wide band chaotic entropy source, all-optical sampler, all-optical comparator and all-optical exclusive-or (XOR), which are mainly realized by four-wave mixing (FWM) and cross-phase modulation (XPM) in highly nonlinear fibers. And we achieve 10 Gbit/s random numbers through numerically simulating all the processes. The entire operations are completed in the all-optical domain, which may overcome the bottleneck problem of electronic devices, and apply directly in high-speed all-optical communication network.
Chaotic oscillation and random-number generation based on nanoscale optical-energy transfer
NASA Astrophysics Data System (ADS)
Naruse, Makoto; Kim, Song-Ju; Aono, Masashi; Hori, Hirokazu; Ohtsu, Motoichi
2014-08-01
By using nanoscale energy-transfer dynamics and density matrix formalism, we demonstrate theoretically and numerically that chaotic oscillation and random-number generation occur in a nanoscale system. The physical system consists of a pair of quantum dots (QDs), with one QD smaller than the other, between which energy transfers via optical near-field interactions. When the system is pumped by continuous-wave radiation and incorporates a timing delay between two energy transfers within the system, it emits optical pulses. We refer to such QD pairs as nano-optical pulsers (NOPs). Irradiating an NOP with external periodic optical pulses causes the oscillating frequency of the NOP to synchronize with the external stimulus. We find that chaotic oscillation occurs in the NOP population when they are connected by an external time delay. Moreover, by evaluating the time-domain signals by statistical-test suites, we confirm that the signals are sufficiently random to qualify the system as a random-number generator (RNG). This study reveals that even relatively simple nanodevices that interact locally with each other through optical energy transfer at scales far below the wavelength of irradiating light can exhibit complex oscillatory dynamics. These findings are significant for applications such as ultrasmall RNGs.
NASA Astrophysics Data System (ADS)
Becker, Markus; Weerawardane, Thushara Lanka; Li, Xi; Görg, Carmelita
Pseudo Random Number Generators (PRNG) are the base for stochastic simulations. The usage of good generators is essential for valid simulation results. OPNET Modeler a well-known tool for simulation of communication networks provides a Pseudo Random Number Generator. The extension of OPNET Modeler with external generators and additional statistical evaluation methods that has been performed for this paper increases the flexibility and options in the simulation studies performed.
Random Numbers and Quantum Computers
ERIC Educational Resources Information Center
McCartney, Mark; Glass, David
2002-01-01
The topic of random numbers is investigated in such a way as to illustrate links between mathematics, physics and computer science. First, the generation of random numbers by a classical computer using the linear congruential generator and logistic map is considered. It is noted that these procedures yield only pseudo-random numbers since…
Random Numbers and Quantum Computers
ERIC Educational Resources Information Center
McCartney, Mark; Glass, David
2002-01-01
The topic of random numbers is investigated in such a way as to illustrate links between mathematics, physics and computer science. First, the generation of random numbers by a classical computer using the linear congruential generator and logistic map is considered. It is noted that these procedures yield only pseudo-random numbers since…
25 CFR 547.14 - What are the minimum technical standards for electronic random number generation?
Code of Federal Regulations, 2013 CFR
2013-04-01
...) Unpredictability; and (3) Non-repeatability. (b) Statistical randomness. (1) Numbers or other designations produced... must pass the statistical tests for randomness to a 99% confidence level, which may include: (i)...
25 CFR 547.14 - What are the minimum technical standards for electronic random number generation?
Code of Federal Regulations, 2014 CFR
2014-04-01
...) Unpredictability; and (3) Non-repeatability. (b) Statistical randomness. (1) Numbers or other designations produced... must pass the statistical tests for randomness to a 99% confidence level, which may include: (i)...
Sheppard, David P; Woods, Steven Paul; Doyle, Katie L; Verduzco, Marizela
2017-02-01
HIV is associated with frontostriatal dysregulation and executive dysfunction. This study evaluated whether HIV-infected individuals evidence deficits in random number generation (RNG), which is a strategic task requiring paced, rule-guided production of digits. In total, 74 HIV+ adults and 54 seronegative comparison participants completed a comprehensive research neuropsychological battery. Participants produced a random digit sequence by avoiding any order and using numbers 1 through 10 for 100 s at a pace of 1 digit/s. Outcomes included intrusions, repetitions, seriation (1-2-3-4), and cycling (median length of gaps between repeating digits). HIV disease was associated with higher levels of seriation and cycling (ps < .05) but not intrusions or repetitions (ps > .10). Among HIV+ individuals, higher seriation was associated with neuropsychological performance including poorer auditory attention, verbal learning, and delayed memory, whereas higher cycling scores were associated with poorer delayed memory and verbal fluency (ps < .05). Higher seriation also was independently associated with self-reported declines in activities of daily living (ADLs) in the HIV+ group. Individuals living with HIV disease evidence moderate difficulties in inhibiting statistically unlikely non-random sequences, which showed medium associations with higher order verbal abilities and may contribute to greater declines in everyday functioning outcomes. Future studies might examine RNG's role in health behaviors such as medical decision-making or medication adherence. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
NASA Astrophysics Data System (ADS)
Czernik, Pawel
2013-10-01
The hardware random number generator based on the 74121 monostable multivibrators for applications in cryptographically secure distributed measurement and control systems with asymmetric resources was presented. This device was implemented on the basis of the physical electronic vibration generator in which the circuit is composed of two "loop" 74121 monostable multivibrators, D flip-flop and external clock signal source. The clock signal, witch control D flip-flop was generated by a computer on one of the parallel port pins. There was presented programmed the author's acquisition process of random data from the measuring system to a computer. The presented system was designed, builded and thoroughly tested in the term of cryptographic security in our laboratory, what there is the most important part of this publication. Real cryptographic security was tested based on the author's software and the software environment called RDieHarder. The obtained results was here presented and analyzed in detail with particular reference to the specificity of distributed measurement and control systems with asymmetric resources.
NEW CORRELATION BETWEEN A HUMAN SUBJECT AND A QUANTUM MECHANICAL RANDOM NUMBER GENERATOR,
EXPERIMENTAL DESIGN, ACCURACY), (* PARAPSYCHOLOGY , STATISTICAL PROCESSES), (*STATISTICAL PROCESSES, MEASUREMENT), (*PERFORMANCE(HUMAN), CORRELATION TECHNIQUES), PROBABILITY, RANDOM VARIABLES, NUMBERS, STATISTICAL TESTS, STUDENTS
Li, Dongfang; Lu, Zhaojun; Zou, Xuecheng; Liu, Zhenglin
2015-01-01
Random number generators (RNG) play an important role in many sensor network systems and applications, such as those requiring secure and robust communications. In this paper, we develop a high-security and high-throughput hardware true random number generator, called PUFKEY, which consists of two kinds of physical unclonable function (PUF) elements. Combined with a conditioning algorithm, true random seeds are extracted from the noise on the start-up pattern of SRAM memories. These true random seeds contain full entropy. Then, the true random seeds are used as the input for a non-deterministic hardware RNG to generate a stream of true random bits with a throughput as high as 803 Mbps. The experimental results show that the bitstream generated by the proposed PUFKEY can pass all standard national institute of standards and technology (NIST) randomness tests and is resilient to a wide range of security attacks. PMID:26501283
Li, Dongfang; Lu, Zhaojun; Zou, Xuecheng; Liu, Zhenglin
2015-10-16
Random number generators (RNG) play an important role in many sensor network systems and applications, such as those requiring secure and robust communications. In this paper, we develop a high-security and high-throughput hardware true random number generator, called PUFKEY, which consists of two kinds of physical unclonable function (PUF) elements. Combined with a conditioning algorithm, true random seeds are extracted from the noise on the start-up pattern of SRAM memories. These true random seeds contain full entropy. Then, the true random seeds are used as the input for a non-deterministic hardware RNG to generate a stream of true random bits with a throughput as high as 803 Mbps. The experimental results show that the bitstream generated by the proposed PUFKEY can pass all standard national institute of standards and technology (NIST) randomness tests and is resilient to a wide range of security attacks.
Sexton, Nicholas J.; Cooper, Richard P.
2014-01-01
Random number generation (RNG) is a complex cognitive task for human subjects, requiring deliberative control to avoid production of habitual, stereotyped sequences. Under various manipulations (e.g., speeded responding, transcranial magnetic stimulation, or neurological damage) the performance of human subjects deteriorates, as reflected in a number of qualitatively distinct, dissociable biases. For example, the intrusion of stereotyped behavior (e.g., counting) increases at faster rates of generation. Theoretical accounts of the task postulate that it requires the integrated operation of multiple, computationally heterogeneous cognitive control (“executive”) processes. We present a computational model of RNG, within the framework of a novel, neuropsychologically-inspired cognitive architecture, ESPro. Manipulating the rate of sequence generation in the model reproduced a number of key effects observed in empirical studies, including increasing sequence stereotypy at faster rates. Within the model, this was due to time limitations on the interaction of supervisory control processes, namely, task setting, proposal of responses, monitoring, and response inhibition. The model thus supports the fractionation of executive function into multiple, computationally heterogeneous processes. PMID:25071644
Oomens, Wouter; Maes, Joseph H. R.; Hasselman, Fred; Egger, Jos I. M.
2015-01-01
The concept of executive functions plays a prominent role in contemporary experimental and clinical studies on cognition. One paradigm used in this framework is the random number generation (RNG) task, the execution of which demands aspects of executive functioning, specifically inhibition and working memory. Data from the RNG task are best seen as a series of successive events. However, traditional RNG measures that are used to quantify executive functioning are mostly summary statistics referring to deviations from mathematical randomness. In the current study, we explore the utility of recurrence quantification analysis (RQA), a non-linear method that keeps the entire sequence intact, as a better way to describe executive functioning compared to traditional measures. To this aim, 242 first- and second-year students completed a non-paced RNG task. Principal component analysis of their data showed that traditional and RQA measures convey more or less the same information. However, RQA measures do so more parsimoniously and have a better interpretation. PMID:26097449
Click, Timothy H.; Kaminski, George A.; Liu, Aibing B.
2010-01-01
We have simulated pure liquid butane, methanol and hydrated alanine polypeptide with the Monte Carlo technique using three kinds of random number generators - the standard Linear Congruential Generator (LCG), a modification of the LCG with additional randomization used in the BOSS software, and the “Mersenne Twister” generator by Matsumoto and Nishimura. While using the latter two random number generators leads to reasonably similar physical features, the LCG produces a significant different results. For the pure fluids, a noticeable expansion occurs. Using the original LCG on butane yields a molecular volume of 171.4 Å3 per molecule compared to ca. 163.6–163.9 Å3 for the other two generators, a deviation of about 5%. For methanol, the LCG produces an average volume of 86.3 Å3 per molecule, which is about 24% higher than the 68.8–70.2 Å3 obtained with the random number generator in BOSS and the generator by Matsumoto and Nishimura. In case of the hydrated tridecaalanine peptide, the volume and energy tend to be noticeably greater with the LCG than with the BOSS (modified LCG) random number generator. For the simulated hydrated extended conformation of tridecaalanine, the difference in volume reached ca. 87%. The uniformity and periodicity of the generators do not seem to play the crucial role in these phenomena. We conclude that it is important to test a random number generator by modeling a system such as the pure liquid methanol with a well-established force field before routinely employing it in Monte Carlo simulations. PMID:20734313
Three criteria for quantum random-number generators based on beam splitters
Svozil, Karl
2009-05-15
We propose three criteria for the generation of random digital strings from quantum beam splitters: (i) three or more mutually exclusive outcomes corresponding to the invocation of three- and higher-dimensional Hilbert spaces, (ii) the mandatory use of pure states in conjugated bases for preparation and detection, and (iii) the use of entangled singlet (unique) states for elimination of bias.
Pawlowski, Marcin Piotr; Jara, Antonio; Ogorzalek, Maciej
2015-01-01
Entropy in computer security is associated with the unpredictability of a source of randomness. The random source with high entropy tends to achieve a uniform distribution of random values. Random number generators are one of the most important building blocks of cryptosystems. In constrained devices of the Internet of Things ecosystem, high entropy random number generators are hard to achieve due to hardware limitations. For the purpose of the random number generation in constrained devices, this work proposes a solution based on the least-significant bits concatenation entropy harvesting method. As a potential source of entropy, on-board integrated sensors (i.e., temperature, humidity and two different light sensors) have been analyzed. Additionally, the costs (i.e., time and memory consumption) of the presented approach have been measured. The results obtained from the proposed method with statistical fine tuning achieved a Shannon entropy of around 7.9 bits per byte of data for temperature and humidity sensors. The results showed that sensor-based random number generators are a valuable source of entropy with very small RAM and Flash memory requirements for constrained devices of the Internet of Things. PMID:26506357
Pawlowski, Marcin Piotr; Jara, Antonio; Ogorzalek, Maciej
2015-10-22
Entropy in computer security is associated with the unpredictability of a source of randomness. The random source with high entropy tends to achieve a uniform distribution of random values. Random number generators are one of the most important building blocks of cryptosystems. In constrained devices of the Internet of Things ecosystem, high entropy random number generators are hard to achieve due to hardware limitations. For the purpose of the random number generation in constrained devices, this work proposes a solution based on the least-significant bits concatenation entropy harvesting method. As a potential source of entropy, on-board integrated sensors (i.e., temperature, humidity and two different light sensors) have been analyzed. Additionally, the costs (i.e., time and memory consumption) of the presented approach have been measured. The results obtained from the proposed method with statistical fine tuning achieved a Shannon entropy of around 7.9 bits per byte of data for temperature and humidity sensors. The results showed that sensor-based random number generators are a valuable source of entropy with very small RAM and Flash memory requirements for constrained devices of the Internet of Things.
Jahanshahi, M; Profice, P; Brown, R G; Ridding, M C; Dirnberger, G; Rothwell, J C
1998-08-01
Random number generation is an attention-demanding task that engages working memory and executive processes. Random number generation requires holding information 'on line', suppression of habitual counting, internally driven response generation and monitoring of responses. Evidence from PET studies suggests that the dorsolateral prefrontal cortex (DLPFC) is involved in the generation of random responses. We examined the effects of short trains of transcranial magnetic stimulation (TMS) over the left or right DLPFC or medial frontal cortex on random number generation in healthy normal participants. As in previous evidence, in control trials without stimulation participants performed poorly on the random number generation task, showing repetition avoidance and a tendency to count. Brief disruption of processing with TMS over the left DLPFC changed the balance of the individuals' counting bias, increasing the most habitual counting in ones and reducing the lower probability response of counting in twos. This differential effect of TMS over the left DLPFC on the balance of the subject's counting bias was not obtained with TMS over the right DLPFC or the medial frontal cortex. The results suggest that, with disruption of the left DLPFC with TMS, habitual counting in ones that has previously been suppressed is released from inhibition. From these findings a network modulation model of random number generation is proposed, whereby suppression of habitual responses is achieved through the modulatory influence of the left DLPFC over a number-associative network in the superior temporal cortex. To allow emergence of appropriate random responses, the left DLPFC inhibits the superior temporal cortex to prevent spreading activation and habitual counting in ones.
Random numbers from vacuum fluctuations
NASA Astrophysics Data System (ADS)
Shi, Yicheng; Chng, Brenda; Kurtsiefer, Christian
2016-07-01
We implement a quantum random number generator based on a balanced homodyne measurement of vacuum fluctuations of the electromagnetic field. The digitized signal is directly processed with a fast randomness extraction scheme based on a linear feedback shift register. The random bit stream is continuously read in a computer at a rate of about 480 Mbit/s and passes an extended test suite for random numbers.
Random numbers from vacuum fluctuations
Shi, Yicheng; Kurtsiefer, Christian; Chng, Brenda
2016-07-25
We implement a quantum random number generator based on a balanced homodyne measurement of vacuum fluctuations of the electromagnetic field. The digitized signal is directly processed with a fast randomness extraction scheme based on a linear feedback shift register. The random bit stream is continuously read in a computer at a rate of about 480 Mbit/s and passes an extended test suite for random numbers.
NASA Astrophysics Data System (ADS)
Wahl, Michael; Leifgen, Matthias; Berlin, Michael; Röhlicke, Tino; Rahn, Hans-Jürgen; Benson, Oliver
2011-04-01
We report the implementation of a quantum random number generator based on photon arrival times. Due to fast and high resolution timing we are able to generate the highest bitrate of any current generator based on photon arrival times. Bias in the raw data due to the exponential distribution of the arrival times is removed by postprocessing which is directly integrated in the field programmable logic of the timing electronics.
A new technique for ultrafast physical random number generation using optical chaos
NASA Astrophysics Data System (ADS)
Elsonbaty, Amr; Hegazy, Salem F.; Obayya, Salah S. A.
2016-04-01
In this paper, we numerically demonstrate a new extraction scheme for generating ultra-fast physically random sequence of bits. For this purpose, we utilize a dual-channel optical chaos source with suppressed time delayed (TD) signature in both the intensity and the phase of its two channels. The proposed technique uses M 1-bit analog-to-digital converters (ADCs) to compare the level of the chaotic intensity signal at time t with its levels after incommensurable delay-interval Tm, where m = {1,2, … , M}. The binary output of each 1-bit ADC is then sampled by a positive-edge-triggered D flip flop. The clock sequence applied to the flip-flops is relatively delayed such that the rising edge of the clock triggering the m flip-flop precedes the rising edge of the clock of a subsequent m+1 flip-flop by a fixed period. The outputs of all flip flops are then combined by means of a parity-check logic. Numerical simulations are carried out using values of parameters at which TD signature is suppressed for chosen values of setup parameters. The 15 statistical tests in Special Publication 800-22 from NIST are applied to the generated random bits in order to examine the randomness quality of these bits for different values of M. The results show that all tests are passed from M = 1 to M = 39 at sampling rate up to 34.5 GHz which indicates that the maximum generation rate of random bits is 2.691 Tb/sec using a chaotic source of single VCSEL and without employing any pre-processing techniques.
Procassini, R J; Beck, B R
2004-12-07
It might be assumed that use of a ''high-quality'' random number generator (RNG), producing a sequence of ''pseudo random'' numbers with a ''long'' repetition period, is crucial for producing unbiased results in Monte Carlo particle transport simulations. While several theoretical and empirical tests have been devised to check the quality (randomness and period) of an RNG, for many applications it is not clear what level of RNG quality is required to produce unbiased results. This paper explores the issue of RNG quality in the context of parallel, Monte Carlo transport simulations in order to determine how ''good'' is ''good enough''. This study employs the MERCURY Monte Carlo code, which incorporates the CNPRNG library for the generation of pseudo-random numbers via linear congruential generator (LCG) algorithms. The paper outlines the usage of random numbers during parallel MERCURY simulations, and then describes the source and criticality transport simulations which comprise the empirical basis of this study. A series of calculations for each test problem in which the quality of the RNG (period of the LCG) is varied provides the empirical basis for determining the minimum repetition period which may be employed without producing a bias in the mean integrated results.
40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Sample selection by random number generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT POLYCHLORINATED BIPHENYLS (PCBs...
Grade, Stéphane; Badets, Arnaud; Pesenti, Mauro
2017-05-01
Numerical magnitude and specific grasping action processing have been shown to interfere with each other because some aspects of numerical meaning may be grounded in sensorimotor transformation mechanisms linked to finger grip control. However, how specific these interactions are to grasping actions is still unknown. The present study tested the specificity of the number-grip relationship by investigating how the observation of different closing-opening stimuli that might or not refer to prehension-releasing actions was able to influence a random number generation task. Participants had to randomly produce numbers after they observed action stimuli representing either closure or aperture of the fingers, the hand or the mouth, or a colour change used as a control condition. Random number generation was influenced by the prior presentation of finger grip actions, whereby observing a closing finger grip led participants to produce small rather than large numbers, whereas observing an opening finger grip led them to produce large rather than small numbers. Hand actions had reduced or no influence on number production; mouth action influence was restricted to opening, with an overproduction of large numbers. Finally, colour changes did not influence number generation. These results show that some characteristics of observed finger, hand and mouth grip actions automatically prime number magnitude, with the strongest effect for finger grasping. The findings are discussed in terms of the functional and neural mechanisms shared between hand actions and number processing, but also between hand and mouth actions. The present study provides converging evidence that part of number semantics is grounded in sensory-motor mechanisms.
Koyama, Kento; Hokunan, Hidekazu; Hasegawa, Mayumi; Kawamura, Shuso; Koseki, Shigenobu
2016-12-01
We investigated a bacterial sample preparation procedure for single-cell studies. In the present study, we examined whether single bacterial cells obtained via 10-fold dilution followed a theoretical Poisson distribution. Four serotypes of Salmonella enterica, three serotypes of enterohaemorrhagic Escherichia coli and one serotype of Listeria monocytogenes were used as sample bacteria. An inoculum of each serotype was prepared via a 10-fold dilution series to obtain bacterial cell counts with mean values of one or two. To determine whether the experimentally obtained bacterial cell counts follow a theoretical Poisson distribution, a likelihood ratio test between the experimentally obtained cell counts and Poisson distribution which parameter estimated by maximum likelihood estimation (MLE) was conducted. The bacterial cell counts of each serotype sufficiently followed a Poisson distribution. Furthermore, to examine the validity of the parameters of Poisson distribution from experimentally obtained bacterial cell counts, we compared these with the parameters of a Poisson distribution that were estimated using random number generation via computer simulation. The Poisson distribution parameters experimentally obtained from bacterial cell counts were within the range of the parameters estimated using a computer simulation. These results demonstrate that the bacterial cell counts of each serotype obtained via 10-fold dilution followed a Poisson distribution. The fact that the frequency of bacterial cell counts follows a Poisson distribution at low number would be applied to some single-cell studies with a few bacterial cells. In particular, the procedure presented in this study enables us to develop an inactivation model at the single-cell level that can estimate the variability of survival bacterial numbers during the bacterial death process.
Wang, Yonggang; Hui, Cong; Liu, Chong; Xu, Chao
2016-04-01
The contribution of this paper is proposing a new entropy extraction mechanism based on sampling phase jitter in ring oscillators to make a high throughput true random number generator in a field programmable gate array (FPGA) practical. Starting from experimental observation and analysis of the entropy source in FPGA, a multi-phase sampling method is exploited to harvest the clock jitter with a maximum entropy and fast sampling speed. This parametrized design is implemented in a Xilinx Artix-7 FPGA, where the carry chains in the FPGA are explored to realize the precise phase shifting. The generator circuit is simple and resource-saving, so that multiple generation channels can run in parallel to scale the output throughput for specific applications. The prototype integrates 64 circuit units in the FPGA to provide a total output throughput of 7.68 Gbps, which meets the requirement of current high-speed quantum key distribution systems. The randomness evaluation, as well as its robustness to ambient temperature, confirms that the new method in a purely digital fashion can provide high-speed high-quality random bit sequences for a variety of embedded applications.
Wang, Yonggang Hui, Cong; Liu, Chong; Xu, Chao
2016-04-15
The contribution of this paper is proposing a new entropy extraction mechanism based on sampling phase jitter in ring oscillators to make a high throughput true random number generator in a field programmable gate array (FPGA) practical. Starting from experimental observation and analysis of the entropy source in FPGA, a multi-phase sampling method is exploited to harvest the clock jitter with a maximum entropy and fast sampling speed. This parametrized design is implemented in a Xilinx Artix-7 FPGA, where the carry chains in the FPGA are explored to realize the precise phase shifting. The generator circuit is simple and resource-saving, so that multiple generation channels can run in parallel to scale the output throughput for specific applications. The prototype integrates 64 circuit units in the FPGA to provide a total output throughput of 7.68 Gbps, which meets the requirement of current high-speed quantum key distribution systems. The randomness evaluation, as well as its robustness to ambient temperature, confirms that the new method in a purely digital fashion can provide high-speed high-quality random bit sequences for a variety of embedded applications.
NASA Astrophysics Data System (ADS)
Wang, Yonggang; Hui, Cong; Liu, Chong; Xu, Chao
2016-04-01
The contribution of this paper is proposing a new entropy extraction mechanism based on sampling phase jitter in ring oscillators to make a high throughput true random number generator in a field programmable gate array (FPGA) practical. Starting from experimental observation and analysis of the entropy source in FPGA, a multi-phase sampling method is exploited to harvest the clock jitter with a maximum entropy and fast sampling speed. This parametrized design is implemented in a Xilinx Artix-7 FPGA, where the carry chains in the FPGA are explored to realize the precise phase shifting. The generator circuit is simple and resource-saving, so that multiple generation channels can run in parallel to scale the output throughput for specific applications. The prototype integrates 64 circuit units in the FPGA to provide a total output throughput of 7.68 Gbps, which meets the requirement of current high-speed quantum key distribution systems. The randomness evaluation, as well as its robustness to ambient temperature, confirms that the new method in a purely digital fashion can provide high-speed high-quality random bit sequences for a variety of embedded applications.
NASA Astrophysics Data System (ADS)
Dyadkin, Iosif G.; Hamilton, Kenneth G.
1997-12-01
Over two hundred congruential pseudorandom number generators, each with a different multiplier, are built into a single assembler routine that returns 32-bit integer and floating-point values. This gives a Monte Carlo user the opportunity of selecting a combination of sequences, so as to provide a greater appearance of chaos. The software makes use of extended 64-bit arithmetic on Intel 386/387 (or higher) chips, thus attaining a period of 2 62 for each of the individual generators. The routine also features entry points that more directly support certain applications, such as well logging in nuclear geophysics. In addition to the customary uniform (0,1) "white noise" generator, the package provides values distributed according to the exponential and Gaussian distributions, random unit vectors in two and three dimensions, as well as Klein-Nishina and neutron scattering distributions.
Stream Cipher Based on Pseudo-Random Number Generation Using Optical Affine Transformation
2000-01-01
using double-random phase encoding," Appl. Opt. 36, pp. 1054-1058, 1997. 6. G. Unnikrishnan , J. Joseph, and K. Singh, "Optical encryption system that...system using three-dimensional keys in the fresnel do- main," Opt. Lett. 24, pp. 762-764, 1999. 8. M . Madjarova, M . Kakuta, M.Yamaguchi, and N. Ohyama...34Optical implementation of the stream cipher based on the irreversible cellular automata algorithm," Opt. Lett. 22, pp. 1624-1626, 1997. 9. M . Kakuta, M
Pseudorandom Number Generators for Mobile Devices: An Examination and Attempt to Improve Randomness
2013-09-01
Improved Cryptanalysis of the Self-Shrinking Generator,” Australasian Conference on Information Security and Privacy (ACISP) 2001 (Lecture Notes in...Computer Science (LNCS), Vol. 4284, (2006). Zenner, Erik, Matthias Krause, Stefan Lucks. 2001. “Improved Cryptanalysis of the Self- Shrinking
NASA Astrophysics Data System (ADS)
Czernik, Pawel
The chaotic signal generator based on the theory of nonlinear dynamical systems for applications in cryptographically secure distributed measurement and control systems with asymmetric resources is presented. This system was implemented on the basis of the physical chaotic electronic vibration generator in which the resonant circuit is composed of two capacitors, two resistors, coil and transistor, called the Colpitts oscillator. The presented system was designed, programmed and thoroughly tested in the term of cryptographic security in our laboratory, what there is the most important part of this publication. True cryptographic security was tested based on the author's software and the software environment called RDieHarder. The obtained results will be here presented and analyzed in detail with particular reference to the specificity of distributed measurement and control systems with asymmetric resources.
Morse, Melvin L; Beem, Lance W
2011-12-01
Reiki therapy is documented for relief of pain and stress. Energetic healing has been documented to alter biologic markers of illness such as hematocrit. True random number generators are reported to be affected by energy healers and spiritually oriented conscious awareness. The patient was a then 54-year-old severely ill man who had hepatitis C types 1 and 2 and who did not improve with conventional therapy. He also suffered from obesity, the metabolic syndrome, asthma, and hypertension. He was treated with experimental high-dose interferon/riboviron therapy with resultant profound anemia and neutropenia. Energetic healing and Reiki therapy was administered initially to enhance the patient's sense of well-being and to relieve anxiety. Possible effects on the patient's absolute neutrophil count and hematocrit were incidentally noted. Reiki therapy was then initiated at times of profound neutropenia to assess its possible effect on the patient's absolute neutrophil count (ANC). Reiki and other energetic healing sessions were monitored with a true random number generator (RNG). Statistically significant relationships were documented between Reiki therapy, a quieting of the electronically created white noise of the RNG during healing sessions, and improvement in the patient's ANC. The immediate clinical result was that the patient could tolerate the high-dose interferon regimen without missing doses because of absolute neutropenia. The patient was initially a late responder to interferon and had been given a 5% chance of clearing the virus. He remains clear of the virus 1 year after treatment. The association between changes in the RNG, Reiki therapy, and a patient's ANC is the first to the authors' knowledge in the medical literature. Future studies assessing the effects of energetic healing on specific biologic markers of disease are anticipated. Concurrent use of a true RNG may prove to correlate with the effectiveness of energetic therapy.
Beem, Lance W.
2011-01-01
Abstract Background Reiki therapy is documented for relief of pain and stress. Energetic healing has been documented to alter biologic markers of illness such as hematocrit. True random number generators are reported to be affected by energy healers and spiritually oriented conscious awareness. Methods The patient was a then 54-year-old severely ill man who had hepatitis C types 1 and 2 and who did not improve with conventional therapy. He also suffered from obesity, the metabolic syndrome, asthma, and hypertension. He was treated with experimental high-dose interferon/riboviron therapy with resultant profound anemia and neutropenia. Energetic healing and Reiki therapy was administered initially to enhance the patient's sense of well-being and to relieve anxiety. Possible effects on the patient's absolute neutrophil count and hematocrit were incidentally noted. Reiki therapy was then initiated at times of profound neutropenia to assess its possible effect on the patient's absolute neutrophil count (ANC). Reiki and other energetic healing sessions were monitored with a true random number generator (RNG). Results Statistically significant relationships were documented between Reiki therapy, a quieting of the electronically created white noise of the RNG during healing sessions, and improvement in the patient's ANC. The immediate clinical result was that the patient could tolerate the high-dose interferon regimen without missing doses because of absolute neutropenia. The patient was initially a late responder to interferon and had been given a 5% chance of clearing the virus. He remains clear of the virus 1 year after treatment. Conclusions The association between changes in the RNG, Reiki therapy, and a patient's ANC is the first to the authors' knowledge in the medical literature. Future studies assessing the effects of energetic healing on specific biologic markers of disease are anticipated. Concurrent use of a true RNG may prove to correlate with the
Investigating the Randomness of Numbers
ERIC Educational Resources Information Center
Pendleton, Kenn L.
2009-01-01
The use of random numbers is pervasive in today's world. Random numbers have practical applications in such far-flung arenas as computer simulations, cryptography, gambling, the legal system, statistical sampling, and even the war on terrorism. Evaluating the randomness of extremely large samples is a complex, intricate process. However, the…
Investigating the Randomness of Numbers
ERIC Educational Resources Information Center
Pendleton, Kenn L.
2009-01-01
The use of random numbers is pervasive in today's world. Random numbers have practical applications in such far-flung arenas as computer simulations, cryptography, gambling, the legal system, statistical sampling, and even the war on terrorism. Evaluating the randomness of extremely large samples is a complex, intricate process. However, the…
ERIC Educational Resources Information Center
Rinehart, Nicole J.; Bradshaw, John L.; Moss, Simon A.; Brereton, Avril V.; Tonge, Bruce J.
2006-01-01
The repetitive, stereotyped and obsessive behaviours, which are core diagnostic features of autism, are thought to be underpinned by executive dysfunction. This study examined executive impairment in individuals with autism and Asperger's disorder using a verbal equivalent of an established pseudo-random number generating task. Different patterns…
Random Numbers from a Delay Equation
NASA Astrophysics Data System (ADS)
Self, Julian; Mackey, Michael C.
2016-10-01
Delay differential equations can have "chaotic" solutions that can be used to mimic Brownian motion. Since a Brownian motion is random in its velocity, it is reasonable to think that a random number generator might be constructed from such a model. In this preliminary study, we consider one specific example of this and show that it satisfies criteria commonly employed in the testing of random number generators (from TestU01's very stringent "Big Crush" battery of tests). A technique termed digit discarding, commonly used in both this generator and physical RNGs using laser feedback systems, is discussed with regard to the maximal Lyapunov exponent. Also, we benchmark the generator to a contemporary common method: the multiple recursive generator, MRG32k3a. Although our method is about 7 times slower than MRG32k3a, there is in principle no apparent limit on the number of possible values that can be generated from the scheme we present here.
Random numbers certified by Bell's theorem.
Pironio, S; Acín, A; Massar, S; de la Giroday, A Boyer; Matsukevich, D N; Maunz, P; Olmschenk, S; Hayes, D; Luo, L; Manning, T A; Monroe, C
2010-04-15
Randomness is a fundamental feature of nature and a valuable resource for applications ranging from cryptography and gambling to numerical simulation of physical and biological systems. Random numbers, however, are difficult to characterize mathematically, and their generation must rely on an unpredictable physical process. Inaccuracies in the theoretical modelling of such processes or failures of the devices, possibly due to adversarial attacks, limit the reliability of random number generators in ways that are difficult to control and detect. Here, inspired by earlier work on non-locality-based and device-independent quantum information processing, we show that the non-local correlations of entangled quantum particles can be used to certify the presence of genuine randomness. It is thereby possible to design a cryptographically secure random number generator that does not require any assumption about the internal working of the device. Such a strong form of randomness generation is impossible classically and possible in quantum systems only if certified by a Bell inequality violation. We carry out a proof-of-concept demonstration of this proposal in a system of two entangled atoms separated by approximately one metre. The observed Bell inequality violation, featuring near perfect detection efficiency, guarantees that 42 new random numbers are generated with 99 per cent confidence. Our results lay the groundwork for future device-independent quantum information experiments and for addressing fundamental issues raised by the intrinsic randomness of quantum theory.
NASA Astrophysics Data System (ADS)
Yang, Yu-Guang; Xu, Peng; Yang, Rui; Zhou, Yi-Hua; Shi, Wei-Min
2016-01-01
Quantum information and quantum computation have achieved a huge success during the last years. In this paper, we investigate the capability of quantum Hash function, which can be constructed by subtly modifying quantum walks, a famous quantum computation model. It is found that quantum Hash function can act as a hash function for the privacy amplification process of quantum key distribution systems with higher security. As a byproduct, quantum Hash function can also be used for pseudo-random number generation due to its inherent chaotic dynamics. Further we discuss the application of quantum Hash function to image encryption and propose a novel image encryption algorithm. Numerical simulations and performance comparisons show that quantum Hash function is eligible for privacy amplification in quantum key distribution, pseudo-random number generation and image encryption in terms of various hash tests and randomness tests. It extends the scope of application of quantum computation and quantum information.
Yang, Yu-Guang; Xu, Peng; Yang, Rui; Zhou, Yi-Hua; Shi, Wei-Min
2016-01-29
Quantum information and quantum computation have achieved a huge success during the last years. In this paper, we investigate the capability of quantum Hash function, which can be constructed by subtly modifying quantum walks, a famous quantum computation model. It is found that quantum Hash function can act as a hash function for the privacy amplification process of quantum key distribution systems with higher security. As a byproduct, quantum Hash function can also be used for pseudo-random number generation due to its inherent chaotic dynamics. Further we discuss the application of quantum Hash function to image encryption and propose a novel image encryption algorithm. Numerical simulations and performance comparisons show that quantum Hash function is eligible for privacy amplification in quantum key distribution, pseudo-random number generation and image encryption in terms of various hash tests and randomness tests. It extends the scope of application of quantum computation and quantum information.
Yang, Yu-Guang; Xu, Peng; Yang, Rui; Zhou, Yi-Hua; Shi, Wei-Min
2016-01-01
Quantum information and quantum computation have achieved a huge success during the last years. In this paper, we investigate the capability of quantum Hash function, which can be constructed by subtly modifying quantum walks, a famous quantum computation model. It is found that quantum Hash function can act as a hash function for the privacy amplification process of quantum key distribution systems with higher security. As a byproduct, quantum Hash function can also be used for pseudo-random number generation due to its inherent chaotic dynamics. Further we discuss the application of quantum Hash function to image encryption and propose a novel image encryption algorithm. Numerical simulations and performance comparisons show that quantum Hash function is eligible for privacy amplification in quantum key distribution, pseudo-random number generation and image encryption in terms of various hash tests and randomness tests. It extends the scope of application of quantum computation and quantum information. PMID:26823196
ERIC Educational Resources Information Center
Griffiths, Martin
2011-01-01
One of the author's undergraduate students recently asked him whether it was possible to generate a random positive integer. After some thought, the author realised that there were plenty of interesting mathematical ideas inherent in her question. So much so in fact, that the author decided to organise a workshop, open both to undergraduates and…
NASA Astrophysics Data System (ADS)
Contassot-Vivier, Sylvain; Couchot, Jean-François; Guyeux, Christophe; Heam, Pierre-Cyrille
Designing a pseudorandom number generator (PRNG) is a difficult and complex task. Many recent works have considered chaotic functions as the basis of built PRNGs: the quality of the output would indeed be an obvious consequence of some chaos properties. However, there is no direct reasoning that goes from chaotic functions to uniform distribution of the output. Moreover, embedding such kind of functions into a PRNG does not necessarily allow to get a chaotic output, which could be required for simulating some chaotic behaviors. In a previous work, some of the authors have proposed the idea of walking into a N-cube where a balanced Hamiltonian cycle has been removed as the basis of a chaotic PRNG. In this article, all the difficult issues observed in the previous work have been tackled. The chaotic behavior of the whole PRNG is proven. The construction of the balanced Hamiltonian cycle is theoretically and practically solved. An upper bound of the expected length of the walk to obtain a uniform distribution is calculated. Finally practical experiments show that the generators successfully pass the classical statistical tests.
Anzak, Anam; Gaynor, Louise; Beigi, Mazda; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Brown, Peter; Jahanshahi, Marjan
2013-01-01
In paced random number generation (RNG) participants are asked to generate numbers between 1 and 9 in a random fashion, in synchrony with a pacing stimulus. Successful task performance can be achieved through control of the main biases known to exist in human RNG compared to a computer generated series: seriation, cycling through a set of available numbers, and repetition avoidance. A role in response inhibition and switching from automatic to controlled processing has previously been ascribed to the subthalamic nucleus (STN). We sought evidence of frequency-specific changes in STN oscillatory activity which could be directly related to use of such strategies during RNG. Local field potentials (LFPs) were recorded from depth electrodes implanted in the STN of 7 patients (14 sides) with Parkinson's disease (PD), when patients were on dopaminergic medication. Patients were instructed to (1) generate a series of 100 numbers between 1 and 9 in a random fashion, and (2) undertake a control serial counting task, both in synchrony with a 0.5 Hz pacing stimulus. Significant increases in LFP power (p ≤ 0.05) across a narrow gamma frequency band (45-60 Hz) during RNG, compared to the control counting task, were observed. Further, the number of 'repeated pairs' (a decline in which reflects repetition avoidance bias in human RNG) was positively correlated with these gamma increases. We therefore suggest that STN gamma activity is relevant for controlled processing, in particular the active selection and repetition of the same number on successive trials. These results are consistent with a frequency-specific role of the STN in executive processes such as suppression of habitual responses and 'switching-on' of more controlled processing strategies. Copyright © 2012 Elsevier Inc. All rights reserved.
Random numbers spring from alpha decay
Frigerio, N.A.; Sanathanan, L.P.; Morley, M.; Clark, N.A.; Tyler, S.A.
1980-05-01
Congruential random number generators, which are widely used in Monte Carlo simulations, are deficient in that the number they generate are concentrated in a relatively small number of hyperplanes. While this deficiency may not be a limitation in small Monte Carlo studies involving a few variables, it introduces a significant bias in large simulations requiring high resolution. This bias was recognized and assessed during preparations for an accident analysis study of nuclear power plants. This report describes a random number device based on the radioactive decay of alpha particles from a /sup 235/U source in a high-resolution gas proportional counter. The signals were fed to a 4096-channel analyzer and for each channel the frequency of signals registered in a 20,000-microsecond interval was recorded. The parity bits of these frequency counts (0 for an even count and 1 for an odd count) were then assembled in sequence to form 31-bit binary random numbers and transcribed to a magnetic tape. This cycle was repeated as many times as were necessary to create 3 million random numbers. The frequency distribution of counts from the present device conforms to the Brockwell-Moyal distribution, which takes into account the dead time of the counter (both the dead time and decay constant of the underlying Poisson process were estimated). Analysis of the count data and tests of randomness on a sample set of the 31-bit binary numbers indicate that this random number device is a highly reliable source of truly random numbers. Its use is, therefore, recommended in Monte Carlo simulations for which the congruential pseudorandom number generators are found to be inadequate. 6 figures, 5 tables.
True random numbers from amplified quantum vacuum.
Jofre, M; Curty, M; Steinlechner, F; Anzolin, G; Torres, J P; Mitchell, M W; Pruneri, V
2011-10-10
Random numbers are essential for applications ranging from secure communications to numerical simulation and quantitative finance. Algorithms can rapidly produce pseudo-random outcomes, series of numbers that mimic most properties of true random numbers while quantum random number generators (QRNGs) exploit intrinsic quantum randomness to produce true random numbers. Single-photon QRNGs are conceptually simple but produce few random bits per detection. In contrast, vacuum fluctuations are a vast resource for QRNGs: they are broad-band and thus can encode many random bits per second. Direct recording of vacuum fluctuations is possible, but requires shot-noise-limited detectors, at the cost of bandwidth. We demonstrate efficient conversion of vacuum fluctuations to true random bits using optical amplification of vacuum and interferometry. Using commercially-available optical components we demonstrate a QRNG at a bit rate of 1.11 Gbps. The proposed scheme has the potential to be extended to 10 Gbps and even up to 100 Gbps by taking advantage of high speed modulation sources and detectors for optical fiber telecommunication devices.
Particle number and random phases
Kandrup, H.E.
1988-09-15
This paper focuses on the particle content of some scalar field as defined with respect to two sets of modes connected via a well-behaved (and unitarily implementable) Bogoliubov transformation. The principal conclusion impacts on the special role of ''random phase'' states, for which the relative phases associated with the projection of the quantum state into two different numbers eigenstates are treated as ''random'' and averaged over in a density matrix. Specifically, it is demonstrated that if, with respect to one set of modes, the field is in a ''random phase'' state, then any other mode decomposition related via a nontrivial Bogoliubov transformation will yield a larger expectation value for the total particle number. This special role of ''random phase'' states is also related to a recently discussed measure of entropy S/sub N/ which assesses the ''spread'' or ''uncertainty'' in particle number. One specific example of all this is the relative particle content in Minkowski space as defined with respect to the modes natural for inertial and uniformly accelerated observers. Another is the initial and final particle numbers detected by two observers in a ''statically bounded'' universe of the form examined by Parker and Zel'dovich.
Mohr, Christine; Koutrakis, Nikolaos; Kuhn, Gustav
2015-01-01
Magical ideation and belief in the paranormal is considered to represent a trait-like character; people either believe in it or not. Yet, anecdotes indicate that exposure to an anomalous event can turn skeptics into believers. This transformation is likely to be accompanied by altered cognitive functioning such as impaired judgments of event likelihood. Here, we investigated whether the exposure to an anomalous event changes individuals’ explicit traditional (religious) and non-traditional (e.g., paranormal) beliefs as well as cognitive biases that have previously been associated with non-traditional beliefs, e.g., repetition avoidance when producing random numbers in a mental dice task. In a classroom, 91 students saw a magic demonstration after their psychology lecture. Before the demonstration, half of the students were told that the performance was done respectively by a conjuror (magician group) or a psychic (psychic group). The instruction influenced participants’ explanations of the anomalous event. Participants in the magician, as compared to the psychic group, were more likely to explain the event through conjuring abilities while the reverse was true for psychic abilities. Moreover, these explanations correlated positively with their prior traditional and non-traditional beliefs. Finally, we observed that the psychic group showed more repetition avoidance than the magician group, and this effect remained the same regardless of whether assessed before or after the magic demonstration. We conclude that pre-existing beliefs and contextual suggestions both influence people’s interpretations of anomalous events and associated cognitive biases. Beliefs and associated cognitive biases are likely flexible well into adulthood and change with actual life events. PMID:25653626
Mohr, Christine; Koutrakis, Nikolaos; Kuhn, Gustav
2014-01-01
Magical ideation and belief in the paranormal is considered to represent a trait-like character; people either believe in it or not. Yet, anecdotes indicate that exposure to an anomalous event can turn skeptics into believers. This transformation is likely to be accompanied by altered cognitive functioning such as impaired judgments of event likelihood. Here, we investigated whether the exposure to an anomalous event changes individuals' explicit traditional (religious) and non-traditional (e.g., paranormal) beliefs as well as cognitive biases that have previously been associated with non-traditional beliefs, e.g., repetition avoidance when producing random numbers in a mental dice task. In a classroom, 91 students saw a magic demonstration after their psychology lecture. Before the demonstration, half of the students were told that the performance was done respectively by a conjuror (magician group) or a psychic (psychic group). The instruction influenced participants' explanations of the anomalous event. Participants in the magician, as compared to the psychic group, were more likely to explain the event through conjuring abilities while the reverse was true for psychic abilities. Moreover, these explanations correlated positively with their prior traditional and non-traditional beliefs. Finally, we observed that the psychic group showed more repetition avoidance than the magician group, and this effect remained the same regardless of whether assessed before or after the magic demonstration. We conclude that pre-existing beliefs and contextual suggestions both influence people's interpretations of anomalous events and associated cognitive biases. Beliefs and associated cognitive biases are likely flexible well into adulthood and change with actual life events.
NASA Astrophysics Data System (ADS)
Lee, Hochul; Ebrahimi, Farbod; Amiri, Pedram Khalili; Wang, Kang L.
2017-05-01
A true random number generator based on perpendicularly magnetized voltage-controlled magnetic tunnel junction devices (MRNG) is presented. Unlike MTJs used in memory applications where a stable bit is needed to store information, in this work, the MTJ is intentionally designed with small perpendicular magnetic anisotropy (PMA). This allows one to take advantage of the thermally activated fluctuations of its free layer as a stochastic noise source. Furthermore, we take advantage of the voltage dependence of anisotropy to temporarily change the MTJ state into an unstable state when a voltage is applied. Since the MTJ has two energetically stable states, the final state is randomly chosen by thermal fluctuation. The voltage controlled magnetic anisotropy (VCMA) effect is used to generate the metastable state of the MTJ by lowering its energy barrier. The proposed MRNG achieves a high throughput (32 Gbps) by implementing a 64 ×64 MTJ array into CMOS circuits and executing operations in a parallel manner. Furthermore, the circuit consumes very low energy to generate a random bit (31.5 fJ/bit) due to the high energy efficiency of the voltage-controlled MTJ switching.
Classical probabilistic realization of “Random Numbers Certified by Bell's Theorem”
NASA Astrophysics Data System (ADS)
Khrennikov, Andrei
2015-07-01
We question the commonly accepted statement that random numbers certified by Bell's theorem carry some special sort of randomness, so to say, quantum randomness or intrinsic randomness. We show that such numbers can be easily generated by classical random generators.
ERIC Educational Resources Information Center
Ben-Ari, Morechai
2004-01-01
The term "random" is frequently used in discussion of the theory of evolution, even though the mathematical concept of randomness is problematic and of little relevance in the theory. Therefore, since the core concept of the theory of evolution is the non-random process of natural selection, the term random should not be used in teaching the…
ERIC Educational Resources Information Center
Ben-Ari, Morechai
2004-01-01
The term "random" is frequently used in discussion of the theory of evolution, even though the mathematical concept of randomness is problematic and of little relevance in the theory. Therefore, since the core concept of the theory of evolution is the non-random process of natural selection, the term random should not be used in teaching the…
Can brains generate random numbers?
NASA Astrophysics Data System (ADS)
Chvátal, V.; Goldsmith, M.
2013-01-01
Motivated by EEG recordings of normal brain activity, we construct arbitrarily large McCulloch-Pitts neural networks that, without any external input, make every subset of their neurons fire in some iteration (and therefore in infinitely many iterations).
A Multi-Threaded Cryptographic Pseudorandom Number Generator Test Suite
2016-09-01
There are multiple applications for pseudorandom number generators, notably in simulation and cryptography . A bad pseudorandom number generator can...multiple applications for pseudorandom number generators, notably in simu- lation and cryptography . A bad pseudorandom number generator can cause...from a truly random sequence to an attacker” [7]. There are multiple applications for PRNGs, notably in simulation and cryptography . Bad PRNGs can
Security of practical private randomness generation
NASA Astrophysics Data System (ADS)
Pironio, Stefano; Massar, Serge
2013-01-01
Measurements on entangled quantum systems necessarily yield outcomes that are intrinsically unpredictable if they violate a Bell inequality. This property can be used to generate certified randomness in a device-independent way, i.e., without making detailed assumptions about the internal working of the quantum devices used to generate the random numbers. Furthermore these numbers are also private; i.e., they appear random not only to the user but also to any adversary that might possess a perfect description of the devices. Since this process requires a small initial random seed to sample the behavior of the quantum devices and to extract uniform randomness from the raw outputs of the devices, one usually speaks of device-independent randomness expansion. The purpose of this paper is twofold. First, we point out that in most real, practical situations, where the concept of device independence is used as a protection against unintentional flaws or failures of the quantum apparatuses, it is sufficient to show that the generated string is random with respect to an adversary that holds only classical side information; i.e., proving randomness against quantum side information is not necessary. Furthermore, the initial random seed does not need to be private with respect to the adversary, provided that it is generated in a way that is independent from the measured systems. The devices, however, will generate cryptographically secure randomness that cannot be predicted by the adversary, and thus one can, given access to free public randomness, talk about private randomness generation. The theoretical tools to quantify the generated randomness according to these criteria were already introduced in S. Pironio [Nature (London)NATUAS0028-083610.1038/nature09008 464, 1021 (2010)], but the final results were improperly formulated. The second aim of this paper is to correct this inaccurate formulation and therefore lay out a precise theoretical framework for practical device
NASA Astrophysics Data System (ADS)
Tang, X.; Wu, Z. M.; Wu, J. G.; Deng, T.; Fan, L.; Zhong, Z. Q.; Chen, J. J.; Xia, G. Q.
2015-01-01
We propose and experimentally demonstrate a novel technique to generate multi-channel high-speed physical random numbers (PRNs) by taking two chaotic signal outputs from mutually coupled semiconductor lasers (MC-SLs) as entropy sources. First, through controlling the operation parameters of the MC-SL system, two time-delay signature (TDS) suppressed chaotic signals can be obtained. Next, each of these two chaotic signals is sampled by an 8 bit analog-to-digital converter (ADC) with a sampling rate of 10 GHz, and then a bitwise exclusive-OR (XOR) operation on the corresponding bits in samples of the chaotic signal and its time delayed signal is implemented to obtain 8 bit XOR data. Furthermore, through selecting the five least significant bits (LSBs) of 8 bit XOR data to form 5 bit Boolean sequences, two sets of PRN streams with a rate up to 50 Gbits s-1 are generated and successfully pass the NIST statistical tests. Finally, merging these two sets of 50 Gbits s-1 PRN streams by an interleaving operation, another set of the 100 Gbits s-1 PRN stream, which meets all the quality criteria of NIST statistical tests, is also acquired.
Quinkert, A. W.; Pfaff, D. W.
2012-01-01
Deep brain stimulation (DBS) has shown promise in the treatment of many neurological and psychiatric disorders as well as a disorder of consciousness, the minimally conscious state (MCS). In the clinic, DBS is always monotonic standard pulses; however, we have hypothesized that temporally patterned pulses might be more efficient in achieving desired behavioral responses. Here we present two experiments on DBS of the central thalamus to increase arousal, as measured by motor activity, and to affect the electroencephalogram (EEG). In the first, we optimized amplitude and frequency in standard stimulation of the central thalamus in intact mice. In the second, the optimized fixed frequency was compared to two alternative temporal patterns, chaotic and random, which were physically identical to each other and fixed frequency in all ways except temporal pattern. In both experiments and with all types of stimulation, DBS of the central thalamus increased arousal as measured by motor activity. These data also revealed that temporal patterning of pulses can modulate response to stimulation. That temporal patterns in DBS of the central thalamus were found to alter motor activity response implies possible usefulness of temporal patterns in DBS of other contexts. More investigation into exactly how temporally patterned stimulation may affect neuronal circuit dynamics is necessary. PMID:22285420
NASA Astrophysics Data System (ADS)
Taylor, Adam; Bennie, Peter; Guyon, Fredric; Cameron, Iain; Glanfield, James; Emam, Omar
2013-08-01
This paper describes a proposal for a space flight demonstration of a low power, compact Dynamically Reconfigurable Programmable Board (DRPB) based upon a minor evolution of the Astrium Janus payload for UKube 1. The Janus payload is one of a number of the payloads selected to be part of the first national UK-Cube satellite (UKube) [1] to be sponsored by the UK Space Agency. In the UKube configuration the demonstrator performs two experiments the first uses firmware to realise an Astrium patented cosmic random number generator for generating secure cryptographic keys while the second monitors the large high performance SRAM based FPGA for SEU and SEFI events allowing correlation with predicted upset rates. This experiment is called the Janus experiment after the two-faced roman god of beginnings and transitions, transitioning from clear text to encrypted and marking the beginning of flying advanced FPGA's on suitable missions.
Williams, Isobel Anne; Wilkinson, Leonora; Limousin, Patricia; Jahanshahi, Marjan
2015-01-01
Deep brain stimulation of the subthalamic nucleus (STN DBS) ameliorates the motor symptoms of Parkinson's disease (PD). However, some aspects of executive control are impaired with STN DBS. We tested the prediction that (i) STN DBS interferes with switching from automatic to controlled processing during fast-paced random number generation (RNG) (ii) STN DBS-induced cognitive control changes are load-dependent. Fifteen PD patients with bilateral STN DBS performed paced-RNG, under three levels of cognitive load synchronised with a pacing stimulus presented at 1, 0.5 and 0.33 Hz (faster rates require greater cognitive control), with DBS on or off. Measures of output randomness were calculated. Countscore 1 (CS1) indicates habitual counting in steps of one (CS1). Countscore 2 (CS2) indicates a more controlled strategy of counting in twos. The fastest rate was associated with an increased CS1 score with STN DBS on compared to off. At the slowest rate, patients had higher CS2 scores with DBS off than on, such that the differences between CS1 and CS2 scores disappeared. We provide evidence for a load-dependent effect of STN DBS on paced RNG in PD. Patients could switch to more controlled RNG strategies during conditions of low cognitive load at slower rates only when the STN stimulators were off, but when STN stimulation was on, they engaged in more automatic habitual counting under increased cognitive load. These findings are consistent with the proposal that the STN implements a switch signal from the medial frontal cortex which enables a shift from automatic to controlled processing.
Williams, Isobel Anne; Wilkinson, Leonora; Limousin, Patricia; Jahanshahi, Marjan
2015-01-01
Background: Deep brain stimulation of the subthalamic nucleus (STN DBS) ameliorates the motor symptoms of Parkinson’s disease (PD). However, some aspects of executive control are impaired with STN DBS. Objective: We tested the prediction that (i) STN DBS interferes with switching from automatic to controlled processing during fast-paced random number generation (RNG) (ii) STN DBS-induced cognitive control changes are load-dependent. Methods: Fifteen PD patients with bilateral STN DBS performed paced-RNG, under three levels of cognitive load synchronised with a pacing stimulus presented at 1, 0.5 and 0.33 Hz (faster rates require greater cognitive control), with DBS on or off. Measures of output randomness were calculated. Countscore 1 (CS1) indicates habitual counting in steps of one (CS1). Countscore 2 (CS2) indicates a more controlled strategy of counting in twos. Results: The fastest rate was associated with an increased CS1 score with STN DBS on compared to off. At the slowest rate, patients had higher CS2 scores with DBS off than on, such that the differences between CS1 and CS2 scores disappeared. Conclusions: We provide evidence for a load-dependent effect of STN DBS on paced RNG in PD. Patients could switch to more controlled RNG strategies during conditions of low cognitive load at slower rates only when the STN stimulators were off, but when STN stimulation was on, they engaged in more automatic habitual counting under increased cognitive load. These findings are consistent with the proposal that the STN implements a switch signal from the medial frontal cortex which enables a shift from automatic to controlled processing. PMID:25720447
An optical ultrafast random bit generator
NASA Astrophysics Data System (ADS)
Kanter, Ido; Aviad, Yaara; Reidler, Igor; Cohen, Elad; Rosenbluh, Michael
2010-01-01
The generation of random bit sequences based on non-deterministic physical mechanisms is of paramount importance for cryptography and secure communications. High data rates also require extremely fast generation rates and robustness to external perturbations. Physical generators based on stochastic noise sources have been limited in bandwidth to ~100 Mbit s-1 generation rates. We present a physical random bit generator, based on a chaotic semiconductor laser, having time-delayed self-feedback, which operates reliably at rates up to 300 Gbit s-1. The method uses a high derivative of the digitized chaotic laser intensity and generates the random sequence by retaining a number of the least significant bits of the high derivative value. The method is insensitive to laser operational parameters and eliminates the necessity for all external constraints such as incommensurate sampling rates and laser external cavity round trip time. The randomness of long bit strings is verified by standard statistical tests.
Experimental Certification of Random Numbers via Quantum Contextuality
NASA Astrophysics Data System (ADS)
Um, Mark; Zhang, Xiang; Zhang, Junhua; Wang, Ye; Yangchao, Shen; Deng, D.-L.; Duan, Lu-Ming; Kim, Kihwan
2013-04-01
The intrinsic unpredictability of measurements in quantum mechanics can be used to produce genuine randomness. Here, we demonstrate a random number generator where the randomness is certified by quantum contextuality in connection with the Kochen-Specker theorem. In particular, we generate random numbers from measurements on a single trapped ion with three internal levels, and certify the generated randomness by showing a bound on the minimum entropy through observation of violation of the Klyachko-Can-Binicioglu-Shumovsky (KCBS) inequality. Concerning the test of the KCBS inequality, we close the detection efficiency loophole for the first time and make it relatively immune to the compatibility loophole. In our experiment, we generate 1 × 105 random numbers that are guaranteed to have 5.2 × 104 bits of minimum entropy with a 99% confidence level.
Fast generation of sparse random kernel graphs
Hagberg, Aric; Lemons, Nathan; Du, Wen -Bo
2015-09-10
The development of kernel-based inhomogeneous random graphs has provided models that are flexible enough to capture many observed characteristics of real networks, and that are also mathematically tractable. We specify a class of inhomogeneous random graph models, called random kernel graphs, that produces sparse graphs with tunable graph properties, and we develop an efficient generation algorithm to sample random instances from this model. As real-world networks are usually large, it is essential that the run-time of generation algorithms scales better than quadratically in the number of vertices n. We show that for many practical kernels our algorithm runs in time at most ο(n(logn)²). As an example, we show how to generate samples of power-law degree distribution graphs with tunable assortativity.
Fast generation of sparse random kernel graphs
Hagberg, Aric; Lemons, Nathan; Du, Wen -Bo
2015-09-10
The development of kernel-based inhomogeneous random graphs has provided models that are flexible enough to capture many observed characteristics of real networks, and that are also mathematically tractable. We specify a class of inhomogeneous random graph models, called random kernel graphs, that produces sparse graphs with tunable graph properties, and we develop an efficient generation algorithm to sample random instances from this model. As real-world networks are usually large, it is essential that the run-time of generation algorithms scales better than quadratically in the number of vertices n. We show that for many practical kernels our algorithm runs in timemore » at most ο(n(logn)²). As an example, we show how to generate samples of power-law degree distribution graphs with tunable assortativity.« less
Integrated-Circuit Pseudorandom-Number Generator
NASA Technical Reports Server (NTRS)
Steelman, James E.; Beasley, Jeff; Aragon, Michael; Ramirez, Francisco; Summers, Kenneth L.; Knoebel, Arthur
1992-01-01
Integrated circuit produces 8-bit pseudorandom numbers from specified probability distribution, at rate of 10 MHz. Use of Boolean logic, circuit implements pseudorandom-number-generating algorithm. Circuit includes eight 12-bit pseudorandom-number generators, outputs are uniformly distributed. 8-bit pseudorandom numbers satisfying specified nonuniform probability distribution are generated by processing uniformly distributed outputs of eight 12-bit pseudorandom-number generators through "pipeline" of D flip-flops, comparators, and memories implementing conditional probabilities on zeros and ones.
Randomness generation based on spontaneous emissions of lasers
NASA Astrophysics Data System (ADS)
Zhou, Hongyi; Yuan, Xiao; Ma, Xiongfeng
2015-06-01
Random numbers play a key role in information science, especially in cryptography. Based on the probabilistic nature of quantum mechanics, quantum random number generators can produce genuine randomness. In particular, random numbers can be produced from laser phase fluctuations with a very high speed, typically in the Gbps regime. In this work, by developing a physical model, we investigate the origin of the randomness in quantum random number generators based on laser phase fluctuations. We show how the randomness essentially stems from spontaneous emissions. The laser phase fluctuation can be quantitatively evaluated from basic principles and qualitatively explained by the Brownian motion model. After taking account of practical device precision, we show that the randomness generation speed is limited by the finite resolution of detection devices. Our result also provides the optimal experiment design in order to achieve the maximum generation speed.
Security of Semi-Device-Independent Random Number Expansion Protocols.
Li, Dan-Dan; Wen, Qiao-Yan; Wang, Yu-Kun; Zhou, Yu-Qian; Gao, Fei
2015-10-27
Semi-device-independent random number expansion (SDI-RNE) protocols require some truly random numbers to generate fresh ones, with making no assumptions on the internal working of quantum devices except for the dimension of the Hilbert space. The generated randomness is certified by non-classical correlation in the prepare-and-measure test. Until now, the analytical relations between the amount of the generated randomness and the degree of non-classical correlation, which are crucial for evaluating the security of SDI-RNE protocols, are not clear under both the ideal condition and the practical one. In the paper, first, we give the analytical relation between the above two factors under the ideal condition. As well, we derive the analytical relation under the practical conditions, where devices' behavior is not independent and identical in each round and there exists deviation in estimating the non-classical behavior of devices. Furthermore, we choose a different randomness extractor (i.e., two-universal random function) and give the security proof.
Security of Semi-Device-Independent Random Number Expansion Protocols
NASA Astrophysics Data System (ADS)
Li, Dan-Dan; Wen, Qiao-Yan; Wang, Yu-Kun; Zhou, Yu-Qian; Gao, Fei
2015-10-01
Semi-device-independent random number expansion (SDI-RNE) protocols require some truly random numbers to generate fresh ones, with making no assumptions on the internal working of quantum devices except for the dimension of the Hilbert space. The generated randomness is certified by non-classical correlation in the prepare-and-measure test. Until now, the analytical relations between the amount of the generated randomness and the degree of non-classical correlation, which are crucial for evaluating the security of SDI-RNE protocols, are not clear under both the ideal condition and the practical one. In the paper, first, we give the analytical relation between the above two factors under the ideal condition. As well, we derive the analytical relation under the practical conditions, where devices’ behavior is not independent and identical in each round and there exists deviation in estimating the non-classical behavior of devices. Furthermore, we choose a different randomness extractor (i.e., two-universal random function) and give the security proof.
Security of Semi-Device-Independent Random Number Expansion Protocols
Li, Dan-Dan; Wen, Qiao-Yan; Wang, Yu-Kun; Zhou, Yu-Qian; Gao, Fei
2015-01-01
Semi-device-independent random number expansion (SDI-RNE) protocols require some truly random numbers to generate fresh ones, with making no assumptions on the internal working of quantum devices except for the dimension of the Hilbert space. The generated randomness is certified by non-classical correlation in the prepare-and-measure test. Until now, the analytical relations between the amount of the generated randomness and the degree of non-classical correlation, which are crucial for evaluating the security of SDI-RNE protocols, are not clear under both the ideal condition and the practical one. In the paper, first, we give the analytical relation between the above two factors under the ideal condition. As well, we derive the analytical relation under the practical conditions, where devices’ behavior is not independent and identical in each round and there exists deviation in estimating the non-classical behavior of devices. Furthermore, we choose a different randomness extractor (i.e., two-universal random function) and give the security proof. PMID:26503335
Techniques for testing the quality of parallel pseudorandom number generators
Cuccaro, S.A.; Mascagni, M.; Pryor, D.V.
1995-12-01
Ensuring that pseudorandom number generators have good randomness properties is more complicated in a multiprocessor implementation than in the uniprocessor case. We discuss simple extensions of uniprocessor testing for SIMD parallel streams, and develop in detail a repeatability test for the SPMD paradigm. Examples of the application of these tests to an additive tagged-Fibonacci generator are also given.
A Random Number Model for Beer's Law-Atom Shadowing
NASA Astrophysics Data System (ADS)
Daniels, R. Scott
1999-01-01
A random-number corpuscular-theory-of-light model for teaching Beer's law is presented. In this model, atoms are considered to have photon-capture cross-sectional areas and to exist in some finite volume. Where by chance one atom lies directly behind another, the first atom is said to cast a shadow on the second, thereby preventing the second atom from participating in the attenuation of radiation at that instant. This model not only produces the linear Beer's law relationship, but it also provides a simple and visual model from which the law can be demonstrated with the use of a computer-spreadsheet random number generator.
Physical Principle for Generation of Randomness
NASA Technical Reports Server (NTRS)
Zak, Michail
2009-01-01
A physical principle (more precisely, a principle that incorporates mathematical models used in physics) has been conceived as the basis of a method of generating randomness in Monte Carlo simulations. The principle eliminates the need for conventional random-number generators. The Monte Carlo simulation method is among the most powerful computational methods for solving high-dimensional problems in physics, chemistry, economics, and information processing. The Monte Carlo simulation method is especially effective for solving problems in which computational complexity increases exponentially with dimensionality. The main advantage of the Monte Carlo simulation method over other methods is that the demand on computational resources becomes independent of dimensionality. As augmented by the present principle, the Monte Carlo simulation method becomes an even more powerful computational method that is especially useful for solving problems associated with dynamics of fluids, planning, scheduling, and combinatorial optimization. The present principle is based on coupling of dynamical equations with the corresponding Liouville equation. The randomness is generated by non-Lipschitz instability of dynamics triggered and controlled by feedback from the Liouville equation. (In non-Lipschitz dynamics, the derivatives of solutions of the dynamical equations are not required to be bounded.)
Quantum Random Numbers Guaranteed by Kochen-Specker Theorem
NASA Astrophysics Data System (ADS)
Um, Mark; Zhang, Xiang; Zhang, Junhua; Wang, Ye; Shen, Yang-Chao; Deng, Dong-Ling; Duan, Lu-Ming; Kim, Kihwan; CQI Team
2013-05-01
We present a random number generator certified by Kochen-Specker (KS) theorem with a trapped ion system. Outcomes of quantum theory are intrinsically random and can be used to produce genuine randomness. In real implementation, however, the true randomness is inevitably mingled with classical noise or control imperfection and cannot be decisively certified. The KS inequality differentiates the results of quantum mechanics from those of classical theory, non-contextual in nature. We demonstrate the experimental violations of the KS inequality, in particular, the Klyachko-Can-Binicioglu-Shumovsky (KCBS) inequality without the detection loophole and reasonably without the compatibility loophole. The violations are used to certify the randomness of a generated string. As a proof of principle, we produce 1 × 105 random numbers that contain 5.2 × 104 bits of minimum entropy. This work was supported by the National Basic Research Program of China Grant 2011CBA00300, 2011CBA00301, 2011CBA00302, the National Natural Science Foundation of China Grant 61073174, 61033001, 61061130540. KK acknowledges the support of the Thousand Young Talents plan.
Generating and using truly random quantum states in Mathematica
NASA Astrophysics Data System (ADS)
Miszczak, Jarosław Adam
2012-01-01
The problem of generating random quantum states is of a great interest from the quantum information theory point of view. In this paper we present a package for Mathematica computing system harnessing a specific piece of hardware, namely Quantis quantum random number generator (QRNG), for investigating statistical properties of quantum states. The described package implements a number of functions for generating random states, which use Quantis QRNG as a source of randomness. It also provides procedures which can be used in simulations not related directly to quantum information processing. Program summaryProgram title: TRQS Catalogue identifier: AEKA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKA_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 7924 No. of bytes in distributed program, including test data, etc.: 88 651 Distribution format: tar.gz Programming language: Mathematica, C Computer: Requires a Quantis quantum random number generator (QRNG, http://www.idquantique.com/true-random-number-generator/products-overview.html) and supporting a recent version of Mathematica Operating system: Any platform supporting Mathematica; tested with GNU/Linux (32 and 64 bit) RAM: Case dependent Classification: 4.15 Nature of problem: Generation of random density matrices. Solution method: Use of a physical quantum random number generator. Running time: Generating 100 random numbers takes about 1 second, generating 1000 random density matrices takes more than a minute.
Intergenerational resource transfers with random offspring numbers
Arrow, Kenneth J.; Levin, Simon A.
2009-01-01
A problem common to biology and economics is the transfer of resources from parents to children. We consider the issue under the assumption that the number of offspring is unknown and can be represented as a random variable. There are 3 basic assumptions. The first assumption is that a given body of resources can be divided into consumption (yielding satisfaction) and transfer to children. The second assumption is that the parents' welfare includes a concern for the welfare of their children; this is recursive in the sense that the children's welfares include concern for their children and so forth. However, the welfare of a child from a given consumption is counted somewhat differently (generally less) than that of the parent (the welfare of a child is “discounted”). The third assumption is that resources transferred may grow (or decline). In economic language, investment, including that in education or nutrition, is productive. Under suitable restrictions, precise formulas for the resulting allocation of resources are found, demonstrating that, depending on the shape of the utility curve, uncertainty regarding the number of offspring may or may not favor increased consumption. The results imply that wealth (stock of resources) will ultimately have a log-normal distribution. PMID:19617553
Generating functions for weighted Hurwitz numbers
NASA Astrophysics Data System (ADS)
Guay-Paquet, Mathieu; Harnad, J.
2017-08-01
Double Hurwitz numbers enumerating weighted n-sheeted branched coverings of the Riemann sphere or, equivalently, weighted paths in the Cayley graph of Sn generated by transpositions are determined by an associated weight generating function. A uniquely determined 1-parameter family of 2D Toda τ -functions of hypergeometric type is shown to consist of generating functions for such weighted Hurwitz numbers. Four classical cases are detailed, in which the weighting is uniform: Okounkov's double Hurwitz numbers for which the ramification is simple at all but two specified branch points; the case of Belyi curves, with three branch points, two with specified profiles; the general case, with a specified number of branch points, two with fixed profiles, the rest constrained only by the genus; and the signed enumeration case, with sign determined by the parity of the number of branch points. Using the exponentiated quantum dilogarithm function as a weight generator, three new types of weighted enumerations are introduced. These determine quantum Hurwitz numbers depending on a deformation parameter q. By suitable interpretation of q, the statistical mechanics of quantum weighted branched covers may be related to that of Bosonic gases. The standard double Hurwitz numbers are recovered in the classical limit.
Random, but Uniform Please: Requirements for Synthetic Weather Generation
USDA-ARS?s Scientific Manuscript database
Synthetic weather generation models often rely on standard uniform random numbers (RN) to simulate stochastic aspects of weather. However, short sequences of RNs, needed to generate certain weather variables, are not necessarily uniformly distributed, as assumed by weather generation models, and may...
Computer routines for probability distributions, random numbers, and related functions
Kirby, W.
1983-01-01
Use of previously coded and tested subroutines simplifies and speeds up program development and testing. This report presents routines that can be used to calculate various probability distributions and other functions of importance in statistical hydrology. The routines are designed as general-purpose Fortran subroutines and functions to be called from user-written main progress. The probability distributions provided include the beta, chi-square, gamma, Gaussian (normal), Pearson Type III (tables and approximation), and Weibull. Also provided are the distributions of the Grubbs-Beck outlier test, Kolmogorov 's and Smirnov 's D, Student 's t, noncentral t (approximate), and Snedecor F. Other mathematical functions include the Bessel function, I sub o, gamma and log-gamma functions, error functions, and exponential integral. Auxiliary services include sorting and printer-plotting. Random number generators for uniform and normal numbers are provided and may be used with some of the above routines to generate numbers from other distributions. (USGS)
Computer routines for probability distributions, random numbers, and related functions
Kirby, W.H.
1980-01-01
Use of previously codes and tested subroutines simplifies and speeds up program development and testing. This report presents routines that can be used to calculate various probability distributions and other functions of importance in statistical hydrology. The routines are designed as general-purpose Fortran subroutines and functions to be called from user-written main programs. The probability distributions provided include the beta, chisquare, gamma, Gaussian (normal), Pearson Type III (tables and approximation), and Weibull. Also provided are the distributions of the Grubbs-Beck outlier test, Kolmogorov 's and Smirnov 's D, Student 's t, noncentral t (approximate), and Snedecor F tests. Other mathematical functions include the Bessel function I (subzero), gamma and log-gamma functions, error functions and exponential integral. Auxiliary services include sorting and printer plotting. Random number generators for uniform and normal numbers are provided and may be used with some of the above routines to generate numbers from other distributions. (USGS)
Random Variate Generation: A Survey.
1980-06-01
Lawrance and Lewis (1977, 1978), Jacobs and Lewis (1977) and Schmeiser and Lal (1979) consider time series having gamma marginal distributions. Price...random variables from probability distributions," Proceedings of the Winter Simulation Confgrnce, 269-280. Lawrance . A.J. and P.A.W. Lewis (1977). "An...exponential moving-average sequence and point process (EMAI)," J. Appl. Prob., 14, 98-113. Lawrance , A.J. and P.A.W. Lewis (1978), "An exponential
The RANLUX Generator:. Resonances in a Random Walk Test
NASA Astrophysics Data System (ADS)
Shchur, Lev N.; Butera, Paolo
Using a recently proposed directed random walk test, we systematically investigate the popular random number generator RANLUX developed by Lüscher and implemented by James. We confirm the good quality of this generator with the recommended luxury level. At a smaller luxury level (for instance equal to 1) resonances are observed in the random walk test. We also find that the lagged Fibonacci and Subtract-with-Carry recipes exhibit similar failures in the random walk test. A revised analysis of the corresponding dynamical systems leads to the observation of resonances in the eigenvalues of Jacobi matrix.
Random Item Generation Is Affected by Age
ERIC Educational Resources Information Center
Multani, Namita; Rudzicz, Frank; Wong, Wing Yiu Stephanie; Namasivayam, Aravind Kumar; van Lieshout, Pascal
2016-01-01
Purpose: Random item generation (RIG) involves central executive functioning. Measuring aspects of random sequences can therefore provide a simple method to complement other tools for cognitive assessment. We examine the extent to which RIG relates to specific measures of cognitive function, and whether those measures can be estimated using RIG…
Random Item Generation Is Affected by Age
ERIC Educational Resources Information Center
Multani, Namita; Rudzicz, Frank; Wong, Wing Yiu Stephanie; Namasivayam, Aravind Kumar; van Lieshout, Pascal
2016-01-01
Purpose: Random item generation (RIG) involves central executive functioning. Measuring aspects of random sequences can therefore provide a simple method to complement other tools for cognitive assessment. We examine the extent to which RIG relates to specific measures of cognitive function, and whether those measures can be estimated using RIG…
Number Rigidity in Superhomogeneous Random Point Fields
NASA Astrophysics Data System (ADS)
Ghosh, Subhro; Lebowitz, Joel
2017-02-01
We give sufficient conditions for the number rigidity of a large class of point processes in dimension d=1 and 2, based on the decay of correlations. Number rigidity implies that the probability distribution of the number of particles in a bounded domain Λ subset R^d, conditional on the configuration on Λ ^\\complement , is concentrated on a single integer N_Λ . Our conditions are: (a) ρ _1(x)= - int _{R^d} ρ _tr^{(2)}(x,y) dy for all x, where ρ _1 and ρ _tr^{(2)} are the intensity and the truncated pair correlation function resp., and (b)|ρ _tr^{(2)}(x,y)| is bounded by C_1[|x-y|+1]^{-2} in d=1 and by C_2[|x-y|+1]^{-(4+ɛ)} in d=2. Condition (a) covers a wide class of processes, including translation invariant or periodic point process on R^d, d=1,2, that are superhomogeneous or hyperuniform (that is the variance of the number of particles in a bounded domain Ω subset R^d grows slower than the volume of Ω ). It also covers determinantal point processes having a projection kernel. Our conditions for number rigidity are satisfied by all known processes with number rigidity in d=1,2. We also observe, in the light of the results of [26], that no such criteria exist in d>2.
Generating high Reynolds-number flows.
NASA Technical Reports Server (NTRS)
Russell, D. A.
1972-01-01
Present test facilities are seriously limited regarding investigations involving high Reynolds numbers due to financial considerations. Quasi-steady testing facilities offer a practical immediate solution to the problem of high-Re testing. A familiar example is the blowdown wind tunnel, but even more flexibility and economy may be provided by using shock-tube devices. The Ludwieg tube is the shock-tube device most often proposed as a means of generating high-Re flows. Two-stage nozzles may be used with a Ludwieg tube. Quasi-steady facilities will be useful only if the available test time exceeds that required to establish steady flow.
On grey levels in random CAPTCHA generation
NASA Astrophysics Data System (ADS)
Newton, Fraser; Kouritzin, Michael A.
2011-06-01
A CAPTCHA is an automatically generated test designed to distinguish between humans and computer programs; specifically, they are designed to be easy for humans but difficult for computer programs to pass in order to prevent the abuse of resources by automated bots. They are commonly seen guarding webmail registration forms, online auction sites, and preventing brute force attacks on passwords. In the following, we address the question: How does adding a grey level to random CAPTCHA generation affect the utility of the CAPTCHA? We treat the problem of generating the random CAPTCHA as one of random field simulation: An initial state of background noise is evolved over time using Gibbs sampling and an efficient algorithm for generating correlated random variables. This approach has already been found to yield highly-readable yet difficult-to-crack CAPTCHAs. We detail how the requisite parameters for introducing grey levels are estimated and how we generate the random CAPTCHA. The resulting CAPTCHA will be evaluated in terms of human readability as well as its resistance to automated attacks in the forms of character segmentation and optical character recognition.
EPCGen2 Pseudorandom Number Generators: Analysis of J3Gen
Peinado, Alberto; Munilla, Jorge; Fúster-Sabater, Amparo
2014-01-01
This paper analyzes the cryptographic security of J3Gen, a promising pseudo random number generator for low-cost passive Radio Frequency Identification (RFID) tags. Although J3Gen has been shown to fulfill the randomness criteria set by the EPCglobal Gen2 standard and is intended for security applications, we describe here two cryptanalytic attacks that question its security claims: (i) a probabilistic attack based on solving linear equation systems; and (ii) a deterministic attack based on the decimation of the output sequence. Numerical results, supported by simulations, show that for the specific recommended values of the configurable parameters, a low number of intercepted output bits are enough to break J3Gen. We then make some recommendations that address these issues. PMID:24721767
Private random numbers produced by entangled ions and certified by Bell's theorem
NASA Astrophysics Data System (ADS)
Hayes, David; Matsukevich, Dzmitry; Maunz, Peter; Monroe, Chris; Olmschenk, Steven
2010-03-01
It has been shown that entangled particles can be used to generate numbers whose privacy and randomness are guaranteed by the violation of a Bell inequality [1,2]. The authenticity of the bit stream produced is guaranteed when the system used can close the detection loophole and when the entangled particles are non-interacting. We report the use of remotely located trapped ions with near perfect state detection efficiency as a private random number generator. By entangling the ions through photon interference and choosing the measurement settings using a pseudo-random number generator, we measure a CHSH correlation function that is more than seven standard deviations above the classical limit. With a total of 3016 events, we are able to certify the generation of 42 new random numbers with 99% confidence. [1] S. Pironio et al.(submitted to Nature, arXiv:0911.3427) [2] Colbeck, R. PhD Dissertation (2007)
On the basic reproduction number in a random environment.
Bacaër, Nicolas; Khaladi, Mohamed
2013-12-01
The concept of basic reproduction number R0 in population dynamics is studied in the case of random environments. For simplicity the dependence between successive environments is supposed to follow a Markov chain. R0 is the spectral radius of a next-generation operator. Its position with respect to 1 always determines population growth or decay in simulations, unlike another parameter suggested in a recent article (Hernandez-Suarez et al., Theor Popul Biol, doi: 10.1016/j.tpb.2012.05.004 , 2012). The position of the latter with respect to 1 determines growth or decay of the population's expectation. R0 is easily computed in the case of scalar population models without any structure. The main emphasis is on discrete-time models but continuous-time models are also considered.
Simulations Using Random-Generated DNA and RNA Sequences
ERIC Educational Resources Information Center
Bryce, C. F. A.
1977-01-01
Using a very simple computer program written in BASIC, a very large number of random-generated DNA or RNA sequences are obtained. Students use these sequences to predict complementary sequences and translational products, evaluate base compositions, determine frequencies of particular triplet codons, and suggest possible secondary structures.…
Implementation of a portable and reproducible parallel pseudorandom number generator
Pryor, D.V.; Cuccaro, S.A.; Mascagni, M.; Robinson, M.L.
1994-12-31
The authors describe in detail the parallel implementation of a family of additive lagged-Fibonacci pseudorandom number generators. The theoretical structure of these generators is exploited to preserve their well-known randomness properties and to provide a parallel system in of distinct cycles. The algorithm presented here solves the reproducibility problem for a far larger class of parallel Monte Carlo applications than has been previously possible. In particular, Monte Carlo applications that undergo ``splitting`` can be coded to be reproducible, independent both of the number of processors and the execution order of the parallel processes. A library of portable C routines (available from the authors) that implements these ideas is also described.
Quantum random bit generation using stimulated Raman scattering.
Bustard, Philip J; Moffatt, Doug; Lausten, Rune; Wu, Guorong; Walmsley, Ian A; Sussman, Benjamin J
2011-12-05
Random number sequences are a critical resource in a wide variety of information systems, including applications in cryptography, simulation, and data sampling. We introduce a quantum random number generator based on the phase measurement of Stokes light generated by amplification of zero-point vacuum fluctuations using stimulated Raman scattering. This is an example of quantum noise amplification using the most noise-free process possible: near unitary quantum evolution. The use of phase offers robustness to classical pump noise and the ability to generate multiple bits per measurement. The Stokes light is generated with high intensity and as a result, fast detectors with high signal-to-noise ratios can be used for measurement, eliminating the need for single-photon sensitive devices. The demonstrated implementation uses optical phonons in bulk diamond.
TURBID: A Routine for Generating Random Turbulent Inflow Data
2011-11-09
Laboratories for Computational Physics and Fluid Dynamics i REPORT DOCUMENTATION PAGE Form ApprovedOMB No. 0704-0188 3 . DATES COVERED (From - To) Standard...in strongly intermittent [ 3 ] or two-dimensional turbulence [4]. In such cases some- what more elaborate methods [5] for generating synthetic...which are returned form the standard random number 3 generator. vfromr in turn uses the function filco, which calculates the filter co- efficients
Negative numbers are generated in the mind.
Ganor-Stern, Dana; Tzelgov, Joseph
2008-01-01
The goal of the present study was to disentangle two possible representations of negative numbers--the holistic representation, where absolute magnitude is integrated with polarity; and the components representation, where absolute magnitude is stored separately from polarity. Participants' performance was examined in two tasks involving numbers from--100 to 100. In the numerical comparison task, participants had to decide which number of a pair was numerically larger/smaller. In the number line task, participants were presented with a spatial number line on which they had to place a number. The results of both tasks support the components representation of negative numbers. The findings suggest that processing of negative numbers does not involve retrieval of their meaning from memory, but rather the integration of the polarity sign with the digits' magnitudes.
49 CFR 229.105 - Steam generator number.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 49 Transportation 4 2010-10-01 2010-10-01 false Steam generator number. 229.105 Section 229.105..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.105 Steam generator number. An identification number shall be marked on the steam generator's...
49 CFR 229.105 - Steam generator number.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 49 Transportation 4 2012-10-01 2012-10-01 false Steam generator number. 229.105 Section 229.105..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.105 Steam generator number. An identification number shall be marked on the steam generator's...
49 CFR 229.105 - Steam generator number.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 49 Transportation 4 2013-10-01 2013-10-01 false Steam generator number. 229.105 Section 229.105..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.105 Steam generator number. An identification number shall be marked on the steam generator's...
49 CFR 229.105 - Steam generator number.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 49 Transportation 4 2014-10-01 2014-10-01 false Steam generator number. 229.105 Section 229.105..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.105 Steam generator number. An identification number shall be marked on the steam generator's...
49 CFR 229.105 - Steam generator number.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 49 Transportation 4 2011-10-01 2011-10-01 false Steam generator number. 229.105 Section 229.105..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.105 Steam generator number. An identification number shall be marked on the steam generator's...
Saturation of number variance in embedded random-matrix ensembles.
Prakash, Ravi; Pandey, Akhilesh
2016-05-01
We study fluctuation properties of embedded random matrix ensembles of noninteracting particles. For ensemble of two noninteracting particle systems, we find that unlike the spectra of classical random matrices, correlation functions are nonstationary. In the locally stationary region of spectra, we study the number variance and the spacing distributions. The spacing distributions follow the Poisson statistics, which is a key behavior of uncorrelated spectra. The number variance varies linearly as in the Poisson case for short correlation lengths but a kind of regularization occurs for large correlation lengths, and the number variance approaches saturation values. These results are known in the study of integrable systems but are being demonstrated for the first time in random matrix theory. We conjecture that the interacting particle cases, which exhibit the characteristics of classical random matrices for short correlation lengths, will also show saturation effects for large correlation lengths.
Building Kindergartners' Number Sense: A Randomized Controlled Study
ERIC Educational Resources Information Center
Jordan, Nancy C.; Glutting, Joseph; Dyson, Nancy; Hassinger-Das, Brenna; Irwin, Casey
2012-01-01
Math achievement in elementary school is mediated by performance and growth in number sense during kindergarten. The aim of the present study was to test the effectiveness of a targeted small-group number sense intervention for high-risk kindergartners from low-income communities. Children were randomly assigned to 1 of 3 groups (n = 44 in each…
Building Kindergartners' Number Sense: A Randomized Controlled Study
ERIC Educational Resources Information Center
Jordan, Nancy C.; Glutting, Joseph; Dyson, Nancy; Hassinger-Das, Brenna; Irwin, Casey
2012-01-01
Math achievement in elementary school is mediated by performance and growth in number sense during kindergarten. The aim of the present study was to test the effectiveness of a targeted small-group number sense intervention for high-risk kindergartners from low-income communities. Children were randomly assigned to 1 of 3 groups (n = 44 in each…
Random generation of RNA secondary structures according to native distributions.
Nebel, Markus E; Scheid, Anika; Weinberg, Frank
2011-10-12
Random biological sequences are a topic of great interest in genome analysis since, according to a powerful paradigm, they represent the background noise from which the actual biological information must differentiate. Accordingly, the generation of random sequences has been investigated for a long time. Similarly, random object of a more complicated structure like RNA molecules or proteins are of interest. In this article, we present a new general framework for deriving algorithms for the non-uniform random generation of combinatorial objects according to the encoding and probability distribution implied by a stochastic context-free grammar. Briefly, the framework extends on the well-known recursive method for (uniform) random generation and uses the popular framework of admissible specifications of combinatorial classes, introducing weighted combinatorial classes to allow for the non-uniform generation by means of unranking. This framework is used to derive an algorithm for the generation of RNA secondary structures of a given fixed size. We address the random generation of these structures according to a realistic distribution obtained from real-life data by using a very detailed context-free grammar (that models the class of RNA secondary structures by distinguishing between all known motifs in RNA structure). Compared to well-known sampling approaches used in several structure prediction tools (such as SFold) ours has two major advantages: Firstly, after a preprocessing step in time O(n2) for the computation of all weighted class sizes needed, with our approach a set of m random secondary structures of a given structure size n can be computed in worst-case time complexity Om⋅n⋅ log(n) while other algorithms typically have a runtime in O(m⋅n2). Secondly, our approach works with integer arithmetic only which is faster and saves us from all the discomforting details of using floating point arithmetic with logarithmized probabilities. A number of
Random generation of RNA secondary structures according to native distributions
2011-01-01
. Conclusion A number of experimental results shows that our random generation method produces realistic output, at least with respect to the appearance of the different structural motifs. The algorithm is available as a webservice at http://wwwagak.cs.uni-kl.de/NonUniRandGen and can be used for generating random secondary structures of any specified RNA type. A link to download an implementation of our method (in Wolfram Mathematica) can be found there, too. PMID:21992500
Efficient biased random bit generation for parallel processing
Slone, Dale M.
1994-09-28
A lattice gas automaton was implemented on a massively parallel machine (the BBN TC2000) and a vector supercomputer (the CRAY C90). The automaton models Burgers equation ρt + ρρ_{x} = vρ_{xx} in 1 dimension. The lattice gas evolves by advecting and colliding pseudo-particles on a 1-dimensional, periodic grid. The specific rules for colliding particles are stochastic in nature and require the generation of many billions of random numbers to create the random bits necessary for the lattice gas. The goal of the thesis was to speed up the process of generating the random bits and thereby lessen the computational bottleneck of the automaton.
Multiprime Blum Blum Shub Pseudorandom Number Generator
2016-09-01
Cryptography , National Institute of Standards and Technology Tests 15. NUMBER OF PAGES 83 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18...1: Introduction Cryptography is a part of our daily lives. Many digital communications require secrecy and authentication over open channels such as...security, of which cryptography is an intrinsic part. Encryption is the process of transforming data, in the form of plaintext, into ciphertext using a
At least some errors are randomly generated (Freud was wrong)
NASA Technical Reports Server (NTRS)
Sellen, A. J.; Senders, J. W.
1986-01-01
An experiment was carried out to expose something about human error generating mechanisms. In the context of the experiment, an error was made when a subject pressed the wrong key on a computer keyboard or pressed no key at all in the time allotted. These might be considered, respectively, errors of substitution and errors of omission. Each of seven subjects saw a sequence of three digital numbers, made an easily learned binary judgement about each, and was to press the appropriate one of two keys. Each session consisted of 1,000 presentations of randomly permuted, fixed numbers broken into 10 blocks of 100. One of two keys should have been pressed within one second of the onset of each stimulus. These data were subjected to statistical analyses in order to probe the nature of the error generating mechanisms. Goodness of fit tests for a Poisson distribution for the number of errors per 50 trial interval and for an exponential distribution of the length of the intervals between errors were carried out. There is evidence for an endogenous mechanism that may best be described as a random error generator. Furthermore, an item analysis of the number of errors produced per stimulus suggests the existence of a second mechanism operating on task driven factors producing exogenous errors. Some errors, at least, are the result of constant probability generating mechanisms with error rate idiosyncratically determined for each subject.
DNA based random key generation and management for OTP encryption.
Zhang, Yunpeng; Liu, Xin; Sun, Manhui
2017-09-01
One-time pad (OTP) is a principle of key generation applied to the stream ciphering method which offers total privacy. The OTP encryption scheme has proved to be unbreakable in theory, but difficult to realize in practical applications. Because OTP encryption specially requires the absolute randomness of the key, its development has suffered from dense constraints. DNA cryptography is a new and promising technology in the field of information security. DNA chromosomes storing capabilities can be used as one-time pad structures with pseudo-random number generation and indexing in order to encrypt the plaintext messages. In this paper, we present a feasible solution to the OTP symmetric key generation and transmission problem with DNA at the molecular level. Through recombinant DNA technology, by using only sender-receiver known restriction enzymes to combine the secure key represented by DNA sequence and the T vector, we generate the DNA bio-hiding secure key and then place the recombinant plasmid in implanted bacteria for secure key transmission. The designed bio experiments and simulation results show that the security of the transmission of the key is further improved and the environmental requirements of key transmission are reduced. Analysis has demonstrated that the proposed DNA-based random key generation and management solutions are marked by high security and usability. Published by Elsevier B.V.
Device- and semi-device-independent random numbers based on noninequality paradox
NASA Astrophysics Data System (ADS)
Li, Hong-Wei; Pawłowski, Marcin; Rahaman, Ramij; Guo, Guang-Can; Han, Zheng-Fu
2015-08-01
In this work, we propose device-independent true random number expansion protocols based on noninequality paradoxes such as Hardy's and Cabello's nonlocality arguments, thus highlighting the noninequality paradox as an important resource for device-independent quantum-information processing, in particular for generating true randomness. As a byproduct, we find that the nonlocal bound of the Cabello argument with arbitrary dimension is the same as the one achieved in the qubits system. More interestingly, we propose a dimension witness paradox based on the Cabello argument which can be used for constructing a semi-device-independent true random number expansion protocol.
Generation of large prime numbers from a sequence of previous prime numbers
NASA Astrophysics Data System (ADS)
Samir, Brahim Belhaouari; Rezk, Youssef A. Y.
2012-09-01
A prime number is co-prime with all the primes as well. This paper utilizes this fact by generating larger prime numbers based on a set of smaller prime numbers. The prime numbers are ordered and each two consecutive primes are coupled to generate their co-prime number formula extending this process larger prime sequence is established. Will the process help us produce larger prime numbers faster and more efficiently? This paper investigates the described process.
Number of distinct sites visited by a subdiffusive random walker.
Yuste, Santos Bravo; Klafter, J; Lindenberg, Katja
2008-03-01
The asymptotic mean number of distinct sites visited by a subdiffusive continuous-time random walker in two dimensions seems not to have been explicitly calculated anywhere in the literature. This number has been calculated for other dimensions for only one specific asymptotic behavior of the waiting time distribution between steps. We present an explicit derivation for two cases in all integer dimensions so as to formally complete a tableau of results. In this tableau we include the dominant as well as subdominant contributions in all integer dimensions. Other quantities that can be calculated from the mean number of distinct sites visited are also discussed.
On the number of connected components of random algebraic hypersurfaces
NASA Astrophysics Data System (ADS)
Fyodorov, Yan V.; Lerario, Antonio; Lundberg, Erik
2015-09-01
We study the expectation of the number of components b0(X) of a random algebraic hypersurface X defined by the zero set in projective space RPn of a random homogeneous polynomial f of degree d. Specifically, we consider invariant ensembles, that is Gaussian ensembles of polynomials that are invariant under an orthogonal change of variables. Fixing n, under some rescaling assumptions on the family of ensembles (as d → ∞), we prove that Eb0(X) has the same order of growth as [ Eb0(X ∩ RP1) ] n. This relates the average number of components of X to the classical problem of M. Kac (1943) on the number of zeros of the random univariate polynomial f|RP1. The proof requires an upper bound for Eb0(X), which we obtain by counting extrema using Random Matrix Theory methods from Fyodorov (2013), and it also requires a lower bound, which we obtain by a modification of the barrier method from Lerario and Lundberg (2015) and Nazarov and Sodin (2009). We also provide quantitative upper bounds on implied constants; for the real Fubini-Study model these estimates provide super-exponential decay (as n → ∞) of the leading coefficient (in d) of Eb0(X) .
Detail of generator number three, oblique. Control panels on the ...
Detail of generator number three, oblique. Control panels on the main floor and on the mezzanine are visible behind and above the generators. - March Air Force Base, Strategic Air Command, Utility Building, 5220 Riverside Drive, Moreno Valley, Riverside County, CA
Generating matrix of the bi-periodic Lucas numbers
NASA Astrophysics Data System (ADS)
Coskun, Arzu; Taskara, Necati
2017-07-01
In this paper, firstly, we introduce the Ql-Generating matrix for the bi-periodic Lucas numbers. Then, by taking into account this matrix representation, we obtain some properties for the bi-periodic Fibonacci and Lucas numbers.
The average crossing number of equilateral random polygons
NASA Astrophysics Data System (ADS)
Diao, Y.; Dobay, A.; Kusner, R. B.; Millett, K.; Stasiak, A.
2003-11-01
In this paper, we study the average crossing number of equilateral random walks and polygons. We show that the mean average crossing number ACN of all equilateral random walks of length n is of the form \\frac{3}{16} n \\ln n +O(n) . A similar result holds for equilateral random polygons. These results are confirmed by our numerical studies. Furthermore, our numerical studies indicate that when random polygons of length n are divided into individual knot types, the \\langle ACN({\\cal K})\\rangle for each knot type \\cal K can be described by a function of the form \\langle ACN({\\cal K})\\rangle=a (n-n_0) \\ln (n-n_0)+b (n-n_0)+c where a, b and c are constants depending on \\cal K and n0 is the minimal number of segments required to form \\cal K . The \\langle ACN({\\cal K})\\rangle profiles diverge from each other, with more complex knots showing higher \\langle ACN({\\cal K})\\rangle than less complex knots. Moreover, the \\langle ACN({\\cal K})\\rangle profiles intersect with the langACNrang profile of all closed walks. These points of intersection define the equilibrium length of \\cal K , i.e., the chain length n_e({\\cal K}) at which a statistical ensemble of configurations with given knot type \\cal K —upon cutting, equilibration and reclosure to a new knot type \\cal K^\\prime —does not show a tendency to increase or decrease \\langle ACN({\\cal K^\\prime)}\\rangle . This concept of equilibrium length seems to be universal, and applies also to other length-dependent observables for random knots, such as the mean radius of gyration langRgrang.
Pseudorandom number generation using chaotic true orbits of the Bernoulli map
Saito, Asaki; Yamaguchi, Akihiro
2016-06-15
We devise a pseudorandom number generator that exactly computes chaotic true orbits of the Bernoulli map on quadratic algebraic integers. Moreover, we describe a way to select the initial points (seeds) for generating multiple pseudorandom binary sequences. This selection method distributes the initial points almost uniformly (equidistantly) in the unit interval, and latter parts of the generated sequences are guaranteed not to coincide. We also demonstrate through statistical testing that the generated sequences possess good randomness properties.
Multistability, chaos, and random signal generation in semiconductor superlattices
NASA Astrophysics Data System (ADS)
Ying, Lei; Huang, Danhong; Lai, Ying-Cheng
2016-06-01
Historically, semiconductor superlattices, artificial periodic structures of different semiconductor materials, were invented with the purpose of engineering or manipulating the electronic properties of semiconductor devices. A key application lies in generating radiation sources, amplifiers, and detectors in the "unusual" spectral range of subterahertz and terahertz (0.1-10 THz), which cannot be readily realized using conventional radiation sources, the so-called THz gap. Efforts in the past three decades have demonstrated various nonlinear dynamical behaviors including chaos, suggesting the potential to exploit chaos in semiconductor superlattices as random signal sources (e.g., random number generators) in the THz frequency range. We consider a realistic model of hot electrons in semiconductor superlattice, taking into account the induced space charge field. Through a systematic exploration of the phase space we find that, when the system is subject to an external electrical driving of a single frequency, chaos is typically associated with the occurrence of multistability. That is, for a given parameter setting, while there are initial conditions that lead to chaotic trajectories, simultaneously there are other initial conditions that lead to regular motions. Transition to multistability, i.e., the emergence of multistability with chaos as a system parameter passes through a critical point, is found and argued to be abrupt. Multistability thus presents an obstacle to utilizing the superlattice system as a reliable and robust random signal source. However, we demonstrate that, when an additional driving field of incommensurate frequency is applied, multistability can be eliminated, with chaos representing the only possible asymptotic behavior of the system. In such a case, a random initial condition will lead to a trajectory landing in a chaotic attractor with probability 1, making quasiperiodically driven semiconductor superlattices potentially as a reliable
Multistability, chaos, and random signal generation in semiconductor superlattices.
Ying, Lei; Huang, Danhong; Lai, Ying-Cheng
2016-06-01
Historically, semiconductor superlattices, artificial periodic structures of different semiconductor materials, were invented with the purpose of engineering or manipulating the electronic properties of semiconductor devices. A key application lies in generating radiation sources, amplifiers, and detectors in the "unusual" spectral range of subterahertz and terahertz (0.1-10 THz), which cannot be readily realized using conventional radiation sources, the so-called THz gap. Efforts in the past three decades have demonstrated various nonlinear dynamical behaviors including chaos, suggesting the potential to exploit chaos in semiconductor superlattices as random signal sources (e.g., random number generators) in the THz frequency range. We consider a realistic model of hot electrons in semiconductor superlattice, taking into account the induced space charge field. Through a systematic exploration of the phase space we find that, when the system is subject to an external electrical driving of a single frequency, chaos is typically associated with the occurrence of multistability. That is, for a given parameter setting, while there are initial conditions that lead to chaotic trajectories, simultaneously there are other initial conditions that lead to regular motions. Transition to multistability, i.e., the emergence of multistability with chaos as a system parameter passes through a critical point, is found and argued to be abrupt. Multistability thus presents an obstacle to utilizing the superlattice system as a reliable and robust random signal source. However, we demonstrate that, when an additional driving field of incommensurate frequency is applied, multistability can be eliminated, with chaos representing the only possible asymptotic behavior of the system. In such a case, a random initial condition will lead to a trajectory landing in a chaotic attractor with probability 1, making quasiperiodically driven semiconductor superlattices potentially as a reliable
Learning Binomial Probability Concepts with Simulation, Random Numbers and a Spreadsheet
ERIC Educational Resources Information Center
Rochowicz, John A., Jr.
2005-01-01
This paper introduces the reader to the concepts of binomial probability and simulation. A spreadsheet is used to illustrate these concepts. Random number generators are great technological tools for demonstrating the concepts of probability. Ideas of approximation, estimation, and mathematical usefulness provide numerous ways of learning…
Expected number of sites visited by a constrained n-step random walk
NASA Astrophysics Data System (ADS)
Larralde, Hernan; Weiss, George H.
1995-08-01
We develop a formalism based on generating functions for calculating the expected number of sites visited by a lattice random walk constrained to visit a fixed point at the nth step. Explicit results are given in the large-n limit when the target point is not too far from the origin.
Random Numbers Demonstrate the Frequency of Type I Errors: Three Spreadsheets for Class Instruction
ERIC Educational Resources Information Center
Duffy, Sean
2010-01-01
This paper describes three spreadsheet exercises demonstrating the nature and frequency of type I errors using random number generation. The exercises are designed specifically to address issues related to testing multiple relations using correlation (Demonstration I), t tests varying in sample size (Demonstration II) and multiple comparisons…
The random walk of a low-Reynolds-number swimmer
NASA Astrophysics Data System (ADS)
Rafaï, Salima; Garcia, Michaël; Berti, Stefano; Peyla, Philippe
2010-11-01
Swimming at a micrometer scale demands particular strategies. Indeed when inertia is negligible as compared to viscous forces (i.e. Reynolds number Re is lower than unity), hydrodynamics equations are reversible in time. To achieve propulsion a low Reynolds number, swimmers must then deform in a way that is not invariant under time reversal. Here we investigate the dispersal properties of self propelled organisms by means of microscopy and cell tracking. Our system of interest is the microalga Chlamydomonas Reinhardtii, a motile single celled green alga about 10 micrometers in diameter that swims with two flagellae. In the case of dilute suspensions, we show that tracked trajectories are well modelled by a correlated random walk. This process is based on short time correlations in the direction of movement called persistence. At longer times, correlations are lost and a standard random walk caracterizes the trajectories. Moreover, high speed imaging enables us to show how speed fluctuations at very short times affect the statistical description of the dynamics. Finally we show how drag forces modify the characteristics of this particular random walk.
Limitations of the number self-consistent random phase approximation
NASA Astrophysics Data System (ADS)
Mariano, Alejandro; Hirsch, Jorge G.
2000-05-01
The quasiparticle random phase approximation (QRPA) equations are solved taking into account the Pauli principle at the expectation value level, and allowing changes in the mean field occupation numbers to minimize the energy while having the correct number of particles in the correlated vacuum. The study of Fermi pn excitations in 76Ge using a realistic Hilbert space shows that the pairing energy gaps in the modified mean field are diminished up to one half of the experimental value when strong proton-neutron correlations are present. Additionally, the Ikeda sum rule for Fermi transitions is violated due to the lack of scattering terms in the phonon operators. These results call for a critical revision of the double β decay half-lives estimated using the QRPA extensions when standard QRPA calculations collapse.
Generating variable and random schedules of reinforcement using Microsoft Excel macros.
Bancroft, Stacie L; Bourret, Jason C
2008-01-01
Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time. Generating schedule values for variable and random reinforcement schedules can be difficult. The present article describes the steps necessary to write macros in Microsoft Excel that will generate variable-ratio, variable-interval, variable-time, random-ratio, random-interval, and random-time reinforcement schedule values.
Generating Variable and Random Schedules of Reinforcement Using Microsoft Excel Macros
Bancroft, Stacie L; Bourret, Jason C
2008-01-01
Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time. Generating schedule values for variable and random reinforcement schedules can be difficult. The present article describes the steps necessary to write macros in Microsoft Excel that will generate variable-ratio, variable-interval, variable-time, random-ratio, random-interval, and random-time reinforcement schedule values. PMID:18595286
Random Sequence for Optimal Low-Power Laser Generated Ultrasound
NASA Astrophysics Data System (ADS)
Vangi, D.; Virga, A.; Gulino, M. S.
2017-08-01
Low-power laser generated ultrasounds are lately gaining importance in the research world, thanks to the possibility of investigating a mechanical component structural integrity through a non-contact and Non-Destructive Testing (NDT) procedure. The ultrasounds are, however, very low in amplitude, making it necessary to use pre-processing and post-processing operations on the signals to detect them. The cross-correlation technique is used in this work, meaning that a random signal must be used as laser input. For this purpose, a highly random and simple-to-create code called T sequence, capable of enhancing the ultrasound detectability, is introduced (not previously available at the state of the art). Several important parameters which characterize the T sequence can influence the process: the number of pulses Npulses , the pulse duration δ and the distance between pulses dpulses . A Finite Element FE model of a 3 mm steel disk has been initially developed to analytically study the longitudinal ultrasound generation mechanism and the obtainable outputs. Later, experimental tests have shown that the T sequence is highly flexible for ultrasound detection purposes, making it optimal to use high Npulses and δ but low dpulses . In the end, apart from describing all phenomena that arise in the low-power laser generation process, the results of this study are also important for setting up an effective NDT procedure using this technology.
The Numbers Game: Phasing in Generated ID Numbers at the University of Oregon
ERIC Educational Resources Information Center
Eveland, Sue
2005-01-01
With all the recent headlines about security breaches and information loss at financial and educational institutions, the higher education community needs to address the issue of using social security numbers as ID numbers. The University of Oregon undertook a change process to assign generated ID numbers to all records in their information…
Measurement-device-independent randomness generation with arbitrary quantum states
NASA Astrophysics Data System (ADS)
Bischof, Felix; Kampermann, Hermann; Bruß, Dagmar
2017-06-01
Measurements of quantum systems can be used to generate classical data that are truly unpredictable for every observer. However, this true randomness needs to be discriminated from randomness due to ignorance or lack of control of the devices. We analyze the randomness gain of a measurement-device-independent setup, consisting of a well-characterized source of quantum states and a completely uncharacterized and untrusted detector. Our framework generalizes previous schemes as arbitrary input states and arbitrary measurements can be analyzed. Our method is used to suggest simple and realistic implementations that yield high randomness generation rates of more than one random bit per qubit for detectors of sufficient quality.
RANDOM PULSE GENERATOR PRODUCING FIDUCIAL MARKS
Nielsen, W.F.
1960-02-01
The apparatus for automatically applying a fiducial marking, having a nonrepetitive pattern, to a plurality of simultaneously made records comprises, in series, a bypass filter, a trigger circuit, and a pulse generator, with printing means connected to and controlled by the pulse generator for simultaneously making the visible fiducial marks on a plurality of simultaneously produced records.
Generation of kth-order random toposequences
NASA Astrophysics Data System (ADS)
Odgers, Nathan P.; McBratney, Alex. B.; Minasny, Budiman
2008-05-01
The model presented in this paper derives toposequences from a digital elevation model (DEM). It is written in ArcInfo Macro Language (AML). The toposequences are called kth-order random toposequences, because they take a random path uphill to the top of a hill and downhill to a stream or valley bottom from a randomly selected seed point, and they are located in a streamshed of order k according to a particular stream-ordering system. We define a kth-order streamshed as the area of land that drains directly to a stream segment of stream order k. The model attempts to optimise the spatial configuration of a set of derived toposequences iteratively by using simulated annealing to maximise the total sum of distances between each toposequence hilltop in the set. The user is able to select the order, k, of the derived toposequences. Toposequences are useful for determining soil sampling locations for use in collecting soil data for digital soil mapping applications. Sampling locations can be allocated according to equal elevation or equal-distance intervals along the length of the toposequence, for example. We demonstrate the use of this model for a study area in the Hunter Valley of New South Wales, Australia. Of the 64 toposequences derived, 32 were first-order random toposequences according to Strahler's stream-ordering system, and 32 were second-order random toposequences. The model that we present in this paper is an efficient method for sampling soil along soil toposequences. The soils along a toposequence are related to each other by the topography they are found in, so soil data collected by this method is useful for establishing soil-landscape rules for the preparation of digital soil maps.
Generating Pseudorandom Numbers From Various Distributions Using C++
2014-06-01
ANY REAL NUMBER double t=1/(1+.3275911* fabs ( x ));//..see Abramowitz and Stegun, 7.1.26 (p. 299...t=1/(1+.3275911* fabs ( x ));//..see Abramowitz and Stegun, 7.1.26 (p. 299) double a[]={.254829592,-.284496736,1.421413741,-1.453152027,1.061405429...CLOCKS_PER_SEC,yRandom::Rand(I)); yRandom::Initialize(I,1),init_genrand(1),g.seed(1); bool check=true; for(int i=0;i�++i){ unsigned x
Sample size in orthodontic randomized controlled trials: are numbers justified?
Koletsi, Despina; Pandis, Nikolaos; Fleming, Padhraig S
2014-02-01
Sample size calculations are advocated by the Consolidated Standards of Reporting Trials (CONSORT) group to justify sample sizes in randomized controlled trials (RCTs). This study aimed to analyse the reporting of sample size calculations in trials published as RCTs in orthodontic speciality journals. The performance of sample size calculations was assessed and calculations verified where possible. Related aspects, including number of authors; parallel, split-mouth, or other design; single- or multi-centre study; region of publication; type of data analysis (intention-to-treat or per-protocol basis); and number of participants recruited and lost to follow-up, were considered. Of 139 RCTs identified, complete sample size calculations were reported in 41 studies (29.5 per cent). Parallel designs were typically adopted (n = 113; 81 per cent), with 80 per cent (n = 111) involving two arms and 16 per cent having three arms. Data analysis was conducted on an intention-to-treat (ITT) basis in a small minority of studies (n = 18; 13 per cent). According to the calculations presented, overall, a median of 46 participants were required to demonstrate sufficient power to highlight meaningful differences (typically at a power of 80 per cent). The median number of participants recruited was 60, with a median of 4 participants being lost to follow-up. Our finding indicates good agreement between projected numbers required and those verified (median discrepancy: 5.3 per cent), although only a minority of trials (29.5 per cent) could be examined. Although sample size calculations are often reported in trials published as RCTs in orthodontic speciality journals, presentation is suboptimal and in need of significant improvement.
Image encryption using random sequence generated from generalized information domain
NASA Astrophysics Data System (ADS)
Xia-Yan, Zhang; Guo-Ji, Zhang; Xuan, Li; Ya-Zhou, Ren; Jie-Hua, Wu
2016-05-01
A novel image encryption method based on the random sequence generated from the generalized information domain and permutation-diffusion architecture is proposed. The random sequence is generated by reconstruction from the generalized information file and discrete trajectory extraction from the data stream. The trajectory address sequence is used to generate a P-box to shuffle the plain image while random sequences are treated as keystreams. A new factor called drift factor is employed to accelerate and enhance the performance of the random sequence generator. An initial value is introduced to make the encryption method an approximately one-time pad. Experimental results show that the random sequences pass the NIST statistical test with a high ratio and extensive analysis demonstrates that the new encryption scheme has superior security.
Number of distinct sites visited by N random walkers
NASA Astrophysics Data System (ADS)
Larralde, Hernan; Trunfio, Paul; Havlin, Shlomo; Stanley, H. Eugene; Weiss, George H.
1992-05-01
We study the number of distinct sites visited by N random walkers after t steps SN(t) under the condition that all the walkers are initially at the origin. We derive asymptotic expressions for the mean number of distinct sites
Independence numbers and chromatic numbers of the random subgraphs of some distance graphs
NASA Astrophysics Data System (ADS)
Bogolubsky, L. I.; Gusev, A. S.; Pyaderkin, M. M.; Raigorodskii, A. M.
2015-10-01
This work is concerned with the Nelson-Hadwiger classical problem of finding the chromatic numbers of distance graphs in ℝn. Most consideration is given to the class of graphs G(n, r, s)= (V(n, r), E(n, r, s)) defined as follows: \\displaystyle V(n, r)=\\bigl\\{\\mathbf{x}=(x_1,\\dots,x_n) : x_i\\in\\{0, 1\\}, x_1+\\dots+x_n=r\\bigr\\},//\\displaystyle E(n, r, s)=\\bigl\\{\\{\\mathbf{x}, \\mathbf{y}: (\\mathbf{x}, \\mathbf{y})=s\\}\\bigr\\}, where (x, y) is the Euclidean inner product. In particular, the chromatic number of G(n, 3, 1) was recently found by Balogh, Kostochka and Raigorodskii. The objects of the study are the random subgraphs 𝒢(G(n, r, s), p) whose edges are independently taken from the set E(n, r, s), each with probability p. The independence number and the chromatic number of such graphs are estimated both from below and from above. In the case when r - s is a prime power and r <= 2s + 1, the order of growth of α(𝒢(G(n, r, s), p)) and χ(𝒢(G(n, r, s), p)) is established. Bibliography: 51 titles.
Synthesizing computer generated holograms with reduced number of perspective projections.
Katz, Barak; Shaked, Natan T; Rosen, Joseph
2007-10-01
We present an improved method for recording a synthesized Fourier hologram under incoherent white-light illumination. The advantage of the method is that the number of real projections needed for generating the hologram is significantly reduced. The new method, designated as synthetic projection holography, is demonstrated experimentally. We show that the synthetic projection holography barely affects the reconstructed images. However, by increasing the number of observed projections one can improve the synthetic projection hologram quality.
Probabilistic generation of random networks taking into account information on motifs occurrence.
Bois, Frederic Y; Gayraud, Ghislaine
2015-01-01
Because of the huge number of graphs possible even with a small number of nodes, inference on network structure is known to be a challenging problem. Generating large random directed graphs with prescribed probabilities of occurrences of some meaningful patterns (motifs) is also difficult. We show how to generate such random graphs according to a formal probabilistic representation, using fast Markov chain Monte Carlo methods to sample them. As an illustration, we generate realistic graphs with several hundred nodes mimicking a gene transcription interaction network in Escherichia coli.
Random noun generation in younger and older adults.
Heuer, Herbert; Janczyk, Markus; Kunde, Wilfried
2010-03-01
We examined age-related changes of executive functions by means of random noun generation. Consistent with previous observations on random letter generation, older participants produced more prepotent responses than younger ones. In the case of random noun generation, prepotent responses are nouns of the same category as the preceding noun. In contrast to previous observations, older participants exhibited stronger repetition avoidance and a stronger tendency toward local evenness-that is, toward equal frequencies of the alternative responses even in short subsequences. These data suggest that at higher adult age inhibition of prepotent responses is impaired. In addition, strategic attentional processes of response selection are strengthened, in particular the application of a heuristic for randomness. In this sense response selection is more controlled in older than in younger adults.
The Reliability of Randomly Generated Math Curriculum-Based Measurements
ERIC Educational Resources Information Center
Strait, Gerald G.; Smith, Bradley H.; Pender, Carolyn; Malone, Patrick S.; Roberts, Jarod; Hall, John D.
2015-01-01
"Curriculum-Based Measurement" (CBM) is a direct method of academic assessment used to screen and evaluate students' skills and monitor their responses to academic instruction and intervention. Interventioncentral.org offers a math worksheet generator at no cost that creates randomly generated "math curriculum-based measures"…
The Reliability of Randomly Generated Math Curriculum-Based Measurements
ERIC Educational Resources Information Center
Strait, Gerald G.; Smith, Bradley H.; Pender, Carolyn; Malone, Patrick S.; Roberts, Jarod; Hall, John D.
2015-01-01
"Curriculum-Based Measurement" (CBM) is a direct method of academic assessment used to screen and evaluate students' skills and monitor their responses to academic instruction and intervention. Interventioncentral.org offers a math worksheet generator at no cost that creates randomly generated "math curriculum-based measures"…
Spline methods for approximating quantile functions and generating random samples
NASA Technical Reports Server (NTRS)
Schiess, J. R.; Matthews, C. G.
1985-01-01
Two cubic spline formulations are presented for representing the quantile function (inverse cumulative distribution function) of a random sample of data. Both B-spline and rational spline approximations are compared with analytic representations of the quantile function. It is also shown how these representations can be used to generate random samples for use in simulation studies. Comparisons are made on samples generated from known distributions and a sample of experimental data. The spline representations are more accurate for multimodal and skewed samples and to require much less time to generate samples than the analytic representation.
Distribution of the number of generations in flux compactifications
NASA Astrophysics Data System (ADS)
Braun, Andreas P.; Watari, Taizan
2014-12-01
Flux compactification of string theory generates an ensemble with a large number of vacua, called the landscape. By using the statistics of various properties of low-energy effective theories in the string landscape, one can therefore hope to provide a scientific foundation to the notion of naturalness. This article discusses how to answer such questions of practical interest by using flux compactification of F-theory. It is found that the distribution is approximately in a factorized form given by distribution on the choice of 7-brane gauge group, that on the number of generations Ngen and that on effective coupling constants. The distribution on Ngen is approximately Gaussian for the range |Ngen|≲10 . The statistical cost of higher-rank gauge group is also discussed.
Phase-Coding Self-Testing Quantum Random Number Generator
NASA Astrophysics Data System (ADS)
Song, Xiao-Tian; Li, Hong-Wei; Yin, Zhen-Qiang; Liang, Wen-Ye; Zhang, Chun-Mei; Han, Yun-Guang; Chen, Wei; Han, Zheng-Fu
2015-08-01
Not Available Supported by the National Basic Research Program of China under Grant Nos 2011CBA00200 and 2011CB921200, the National Natural Science Foundation of China under Grant Nos 61201239, 61205118, 11304397 and 61475148, and the Strategic Priority Research Program (B) of Chinese Academy of Sciences under Grant Nos XDB01030100 and XDB01030300.
Towards the generation of random bits at terahertz rates based on a chaotic semiconductor laser
NASA Astrophysics Data System (ADS)
Kanter, Ido; Aviad, Yaara; Reidler, Igor; Cohen, Elad; Rosenbluh, Michael
2010-06-01
Random bit generators (RBGs) are important in many aspects of statistical physics and crucial in Monte-Carlo simulations, stochastic modeling and quantum cryptography. The quality of a RBG is measured by the unpredictability of the bit string it produces and the speed at which the truly random bits can be generated. Deterministic algorithms generate pseudo-random numbers at high data rates as they are only limited by electronic hardware speed, but their unpredictability is limited by the very nature of their deterministic origin. It is widely accepted that the core of any true RBG must be an intrinsically non-deterministic physical process, e.g. measuring thermal noise from a resistor. Owing to low signal levels, such systems are highly susceptible to bias, introduced by amplification, and to small nonrandom external perturbations resulting in a limited generation rate, typically less than 100M bit/s. We present a physical random bit generator, based on a chaotic semiconductor laser, having delayed optical feedback, which operates reliably at rates up to 300Gbit/s. The method uses a high derivative of the digitized chaotic laser intensity and generates the random sequence by retaining a number of the least significant bits of the high derivative value. The method is insensitive to laser operational parameters and eliminates the necessity for all external constraints such as incommensurate sampling rates and laser external cavity round trip time. The randomness of long bit strings is verified by standard statistical tests.
Secure self-calibrating quantum random-bit generator
Fiorentino, M.; Santori, C.; Spillane, S. M.; Beausoleil, R. G.; Munro, W. J.
2007-03-15
Random-bit generators (RBGs) are key components of a variety of information processing applications ranging from simulations to cryptography. In particular, cryptographic systems require 'strong' RBGs that produce high-entropy bit sequences, but traditional software pseudo-RBGs have very low entropy content and therefore are relatively weak for cryptography. Hardware RBGs yield entropy from chaotic or quantum physical systems and therefore are expected to exhibit high entropy, but in current implementations their exact entropy content is unknown. Here we report a quantum random-bit generator (QRBG) that harvests entropy by measuring single-photon and entangled two-photon polarization states. We introduce and implement a quantum tomographic method to measure a lower bound on the 'min-entropy' of the system, and we employ this value to distill a truly random-bit sequence. This approach is secure: even if an attacker takes control of the source of optical states, a secure random sequence can be distilled.
Narrow-band generation in random distributed feedback fiber laser.
Sugavanam, Srikanth; Tarasov, Nikita; Shu, Xuewen; Churkin, Dmitry V
2013-07-15
Narrow-band emission of spectral width down to ~0.05 nm line-width is achieved in the random distributed feedback fiber laser employing narrow-band fiber Bragg grating or fiber Fabry-Perot interferometer filters. The observed line-width is ~10 times less than line-width of other demonstrated up to date random distributed feedback fiber lasers. The random DFB laser with Fabry-Perot interferometer filter provides simultaneously multi-wavelength and narrow-band (within each line) generation with possibility of further wavelength tuning.
Generating and controlling homogeneous air turbulence using random jet arrays
NASA Astrophysics Data System (ADS)
Carter, Douglas; Petersen, Alec; Amili, Omid; Coletti, Filippo
2016-12-01
The use of random jet arrays, already employed in water tank facilities to generate zero-mean-flow homogeneous turbulence, is extended to air as a working fluid. A novel facility is introduced that uses two facing arrays of individually controlled jets (256 in total) to force steady homogeneous turbulence with negligible mean flow, shear, and strain. Quasi-synthetic jet pumps are created by expanding pressurized air through small straight nozzles and are actuated by fast-response low-voltage solenoid valves. Velocity fields, two-point correlations, energy spectra, and second-order structure functions are obtained from 2D PIV and are used to characterize the turbulence from the integral-to-the Kolmogorov scales. Several metrics are defined to quantify how well zero-mean-flow homogeneous turbulence is approximated for a wide range of forcing and geometric parameters. With increasing jet firing time duration, both the velocity fluctuations and the integral length scales are augmented and therefore the Reynolds number is increased. We reach a Taylor-microscale Reynolds number of 470, a large-scale Reynolds number of 74,000, and an integral-to-Kolmogorov length scale ratio of 680. The volume of the present homogeneous turbulence, the largest reported to date in a zero-mean-flow facility, is much larger than the integral length scale, allowing for the natural development of the energy cascade. The turbulence is found to be anisotropic irrespective of the distance between the jet arrays. Fine grids placed in front of the jets are effective at modulating the turbulence, reducing both velocity fluctuations and integral scales. Varying the jet-to-jet spacing within each array has no effect on the integral length scale, suggesting that this is dictated by the length scale of the jets.
Phase transition in a stochastic prime-number generator.
Luque, Bartolo; Lacasa, Lucas; Miramontes, Octavio
2007-07-01
We introduce a stochastic algorithm that acts as a prime-number generator. The dynamics of this algorithm gives rise to a continuous phase transition, which separates a phase where the algorithm is able to reduce a whole set of integers into primes and a phase where the system reaches a frozen state with low prime density. We present both numerical simulations and an analytical approach in terms of an annealed approximation, by means of which the data are collapsed. A critical slowing-down phenomenon is also outlined.
Intensive statistical complexity measure of pseudorandom number generators
NASA Astrophysics Data System (ADS)
Larrondo, H. A.; González, C. M.; Martín, M. T.; Plastino, A.; Rosso, O. A.
2005-10-01
A Statistical Complexity measure has been recently proposed to quantify the performance of chaotic Pseudorandom number generators (PRNG) (Physica A 354 (2005) 281). Here we revisit this quantifier and introduce two important improvements: (i) consideration of an intensive statistical complexity (Physica A 334 (2004) 119), and (ii) following the prescription of Brand and Pompe (Phys. Rev. Lett. 88 (2002) 174102-1) in evaluating the probability distribution associated with the PRNG. The ensuing new measure is applied to a very well-tested PRNG advanced by Marsaglia.
All-optical quantum random bit generation from intrinsically binary phase of parametric oscillators.
Marandi, Alireza; Leindecker, Nick C; Vodopyanov, Konstantin L; Byer, Robert L
2012-08-13
We demonstrate a novel all-optical quantum random number generator (RNG) based on above-threshold binary phase state selection in a degenerate optical parametric oscillator (OPO). Photodetection is not a part of the random process, and no post processing is required for the generated bit sequence. We show that the outcome is statistically random with 99% confidence, and verify that the randomness is due to the phase of initiating photons generated through spontaneous parametric down conversion of the pump, with negligible contribution of classical noise sources. With the use of micro- and nanoscale OPO resonators, this technique offers a promise for simple, robust, and high-speed on-chip all-optical quantum RNGs.
Simulation and study of small numbers of random events
NASA Technical Reports Server (NTRS)
Shelton, R. D.
1986-01-01
Random events were simulated by computer and subjected to various statistical methods to extract important parameters. Various forms of curve fitting were explored, such as least squares, least distance from a line, maximum likelihood. Problems considered were dead time, exponential decay, and spectrum extraction from cosmic ray data using binned data and data from individual events. Computer programs, mostly of an iterative nature, were developed to do these simulations and extractions and are partially listed as appendices. The mathematical basis for the compuer programs is given.
NASA Astrophysics Data System (ADS)
Mironowicz, Piotr; Tavakoli, Armin; Hameedi, Alley; Marques, Breno; Pawłowski, Marcin; Bourennane, Mohamed
2016-06-01
Quantum communication with systems of dimension larger than two provides advantages in information processing tasks. Examples include higher rates of key distribution and random number generation. The main disadvantage of using such multi-dimensional quantum systems is the increased complexity of the experimental setup. Here, we analyze a not-so-obvious problem: the relation between randomness certification and computational requirements of the post-processing of experimental data. In particular, we consider semi-device independent randomness certification from an experiment using a four dimensional quantum system to violate the classical bound of a random access code. Using state-of-the-art techniques, a smaller quantum violation requires more computational power to demonstrate randomness, which at some point becomes impossible with today’s computers although the randomness is (probably) still there. We show that by dedicating more input settings of the experiment to randomness certification, then by more computational postprocessing of the experimental data which corresponds to a quantum violation, one may increase the amount of certified randomness. Furthermore, we introduce a method that significantly lowers the computational complexity of randomness certification. Our results show how more randomness can be generated without altering the hardware and indicate a path for future semi-device independent protocols to follow.
Dynamics of asynchronous random Boolean networks with asynchrony generated by stochastic processes.
Deng, Xutao; Geng, Huimin; Matache, Mihaela Teodora
2007-03-01
An asynchronous Boolean network with N nodes whose states at each time point are determined by certain parent nodes is considered. We make use of the models developed by Matache and Heidel [Matache, M.T., Heidel, J., 2005. Asynchronous random Boolean network model based on elementary cellular automata rule 126. Phys. Rev. E 71, 026232] for a constant number of parents, and Matache [Matache, M.T., 2006. Asynchronous random Boolean network model with variable number of parents based on elementary cellular automata rule 126. IJMPB 20 (8), 897-923] for a varying number of parents. In both these papers the authors consider an asynchronous updating of all nodes, with asynchrony generated by various random distributions. We supplement those results by using various stochastic processes as generators for the number of nodes to be updated at each time point. In this paper we use the following stochastic processes: Poisson process, random walk, birth and death process, Brownian motion, and fractional Brownian motion. We study the dynamics of the model through sensitivity of the orbits to initial values, bifurcation diagrams, and fixed-point analysis. The dynamics of the system show that the number of nodes to be updated at each time point is of great importance, especially for the random walk, the birth and death, and the Brownian motion processes. Small or moderate values for the number of updated nodes generate order, while large values may generate chaos depending on the underlying parameters. The Poisson process generates order. With fractional Brownian motion, as the values of the Hurst parameter increase, the system exhibits order for a wider range of combinations of the underlying parameters.
Impact of random numbers on parallel Monte Carlo application
Pandey, Ras B.
2002-10-22
A number of graduate students are involved at various level of research in this project. We investigate the basic issues in materials using Monte Carlo simulations with specific interest in heterogeneous materials. Attempts have been made to seek collaborations with the DOE laboratories. Specific details are given.
NASA Astrophysics Data System (ADS)
Dai, Liyi
2016-05-01
Stochastic optimization is a fundamental problem that finds applications in many areas including biological and cognitive sciences. The classical stochastic approximation algorithm for iterative stochastic optimization requires gradient information of the sample object function that is typically difficult to obtain in practice. Recently there has been renewed interests in derivative free approaches to stochastic optimization. In this paper, we examine the rates of convergence for the Kiefer-Wolfowitz algorithm and the mirror descent algorithm, by approximating gradient using finite differences generated through common random numbers. It is shown that the convergence of these algorithms can be accelerated by controlling the implementation of the finite differences. Particularly, it is shown that the rate can be increased to n-2/5 in general and to n-1/2, the best possible rate of stochastic approximation, in Monte Carlo optimization for a broad class of problems, in the iteration number n.
High-efficiency generation in a short random fiber laser
NASA Astrophysics Data System (ADS)
Vatnik, I. D.; Churkin, D. V.; Podivilov, E. V.; Babin, S. A.
2014-07-01
We demonstrate a high-efficiency random lasing in a 850 m span of a phosphosilicate fiber. Random distributed feedback owing to the Rayleigh backscattering in the fiber enables narrowband generation with output power of up to 7.3 W at the Stokes wavelength λS = 1308 nm from 11 W of the pump power at λP = 1115 nm. The laser demonstrates unique generation efficiency. Near the generation threshold, more than 2 W of output power is generated from only 0.5 W of pump power excess over the generation threshold. At high pump power, the quantum conversion efficiency defined as a ratio of generated and pump photons at the laser output exceeds 100%. It is explained by the fact that every pump photon is converted into the Stokes photon far from the output fiber end, while the Stokes photons have lower attenuation than the pump photons.
Quantum random bit generation using energy fluctuations in stimulated Raman scattering.
Bustard, Philip J; England, Duncan G; Nunn, Josh; Moffatt, Doug; Spanner, Michael; Lausten, Rune; Sussman, Benjamin J
2013-12-02
Random number sequences are a critical resource in modern information processing systems, with applications in cryptography, numerical simulation, and data sampling. We introduce a quantum random number generator based on the measurement of pulse energy quantum fluctuations in Stokes light generated by spontaneously-initiated stimulated Raman scattering. Bright Stokes pulse energy fluctuations up to five times the mean energy are measured with fast photodiodes and converted to unbiased random binary strings. Since the pulse energy is a continuous variable, multiple bits can be extracted from a single measurement. Our approach can be generalized to a wide range of Raman active materials; here we demonstrate a prototype using the optical phonon line in bulk diamond.
Number-conserving random phase approximation with analytically integrated matrix elements
Kyotoku, M. ); Schmid, K.W. ); Gruemmer, F. ); Faessler, A. )
1990-01-01
In the present paper a number conserving random phase approximation is derived as a special case of the recently developed random phase approximation in general symmetry projected quasiparticle mean fields. All the occurring integrals induced by the number projection are performed analytically after writing the various overlap and energy matrices in the random phase approximation equation as polynomials in the gauge angle. In the limit of a large number of particles the well-known pairing vibration matrix elements are recovered. We also present a new analytically number projected variational equation for the number conserving pairing problem.
Cascaded Cerenkov third-harmonic generation in random quadratic media
Ayoub, Mousa; Roedig, Philip; Imbrock, Joerg; Denz, Cornelia
2011-12-12
We investigate experimentally and theoretically the conical emission of Cerenkov-type third-harmonic generation in strontium barium niobate of random 2D-{chi}{sup (2)} distribution. The azimuthal intensity distribution is explained by the polarization properties of the fundamental and Cerenkov second-harmonic waves, depending on the cascaded origin of the generation process. Moreover, we show the role of the individual domain shape in an additional modulation on the conical emission, controlled by the electrical switching of the spontaneous polarization of the ferroelectric medium.
Differential-phase-shift quantum-key-distribution protocol with a small number of random delays
NASA Astrophysics Data System (ADS)
Hatakeyama, Yuki; Mizutani, Akihiro; Kato, Go; Imoto, Nobuyuki; Tamaki, Kiyoshi
2017-04-01
The differential-phase-shift (DPS) quantum-key-distribution (QKD) protocol was proposed aiming at simple implementation, but it can tolerate only a small disturbance in a quantum channel. The round-robin DPS (RRDPS) protocol could be a good solution for this problem, which in fact can tolerate even up to 50 % of a bit error rate. Unfortunately, however, such a high tolerance can be achieved only when we compromise the simplicity, i.e., Bob's measurement must involve a large number of random delays (|R | denotes its number), and in a practical regime of |R | being small, the tolerance is low. In this paper, we propose a DPS protocol to achieve a higher tolerance than the one in the original DPS protocol, in which the measurement setup is less demanding than the one of the RRDPS protocol for the high tolerance regime. We call our protocol the small-number-random DPS (SNRDPS) protocol, and in this protocol, we add only a small amount of randomness to the original DPS protocol, i.e., 2 ≤|R |≤10 . In fact, we found that the performance of the SNRDPS protocol is significantly enhanced over the original DPS protocol only by employing a few additional delays such as |R |=2 . Also, we found that the key generation rate of the SNRDPS protocol outperforms the RRDPS protocol without monitoring the bit error rate when it is less than 5 % and |R |≤10 . Our protocol is an intermediate protocol between the original DPS protocol and the RRDPS protocol, and it increases the variety of the DPS-type protocols with quantified security.
Generating Small Numbers by Tunneling in Multi-Throat Compactifications
Silverstein, Eva M
2001-07-25
A generic F-theory compactification containing many D3 branes develops multiple brane throats. The interaction of observers residing inside different throats involves tunneling suppression and, as a result, is very weak. This suggests a new mechanism for generating small numbers in Nature. One application is to the hierarchy problem: large supersymmetry breaking near the unification scale inside a shallow throat causes TeV-scale SUSY-breaking inside the standard-model throat. Another application, inspired by nuclear-decay, is in designing naturally long-lived particles: a cold dark matter particle residing near the standard model brane decays to an approximate CFT-state of a longer throat within a Hubble time. This suggests that most of the mass of the universe today could consist of CFT-matter and may soften structure formation at sub-galactic scales. The tunneling calculation demonstrates that the coupling between two throats is dominated by higher dimensional modes and consequently is much larger than a naive application of holography might suggest.
Shteingart, Hanan; Loewenstein, Yonatan
2016-01-01
There is a long history of experiments in which participants are instructed to generate a long sequence of binary random numbers. The scope of this line of research has shifted over the years from identifying the basic psychological principles and/or the heuristics that lead to deviations from randomness, to one of predicting future choices. In this paper, we used generalized linear regression and the framework of Reinforcement Learning in order to address both points. In particular, we used logistic regression analysis in order to characterize the temporal sequence of participants' choices. Surprisingly, a population analysis indicated that the contribution of the most recent trial has only a weak effect on behavior, compared to more preceding trials, a result that seems irreconcilable with standard sequential effects that decay monotonously with the delay. However, when considering each participant separately, we found that the magnitudes of the sequential effect are a monotonous decreasing function of the delay, yet these individual sequential effects are largely averaged out in a population analysis because of heterogeneity. The substantial behavioral heterogeneity in this task is further demonstrated quantitatively by considering the predictive power of the model. We show that a heterogeneous model of sequential dependencies captures the structure available in random sequence generation. Finally, we show that the results of the logistic regression analysis can be interpreted in the framework of reinforcement learning, allowing us to compare the sequential effects in the random sequence generation task to those in an operant learning task. We show that in contrast to the random sequence generation task, sequential effects in operant learning are far more homogenous across the population. These results suggest that in the random sequence generation task, different participants adopt different cognitive strategies to suppress sequential dependencies when
A top-down model to generate ensembles of runoff from a large number of hillslopes
NASA Astrophysics Data System (ADS)
Furey, P. R.; Gupta, V. K.; Troutman, B. M.
2013-09-01
We hypothesize that total hillslope water loss for a rainfall-runoff event is inversely related to a function of a lognormal random variable, based on basin- and point-scale observations taken from the 21 km2 Goodwin Creek Experimental Watershed (GCEW) in Mississippi, USA. A top-down approach is used to develop a new runoff generation model both to test our physical-statistical hypothesis and to provide a method of generating ensembles of runoff from a large number of hillslopes in a basin. The model is based on the assumption that the probability distributions of a runoff/loss ratio have a space-time rescaling property. We test this assumption using streamflow and rainfall data from GCEW. For over 100 rainfall-runoff events, we find that the spatial probability distributions of a runoff/loss ratio can be rescaled to a new distribution that is common to all events. We interpret random within-event differences in runoff/loss ratios in the model to arise from soil moisture spatial variability. Observations of water loss during events in GCEW support this interpretation. Our model preserves water balance in a mean statistical sense and supports our hypothesis. As an example, we use the model to generate ensembles of runoff at a large number of hillslopes for a rainfall-runoff event in GCEW.
Generation of Large Numbers of Independently Transformed Fertile Barley Plants.
Wan, Y.; Lemaux, P. G.
1994-01-01
A rapid, efficient, and reproducible system to generate large numbers of independently transformed, self-fertile, transgenic barley (Hordeum vulgare L.) plants is described. Immature zygotic embryos, young callus, and microspore-derived embryos were bombarded with a plasmid containing bar and uidA either alone or in combination with another plasmid containing a barley yellow dwarf virus coat protein (BYDVcp) gene. A total of 91 independent bialaphos-resistant callus lines expressed functional phosphinothricin acetyltransferase, the product of bar. Integration of bar was confirmed by DNA hybridization in the 67 lines analyzed. Co-transformation frequencies of 84 and 85% were determined for the two linked genes (bar and uidA) and for two unlinked genes (bar and the BYDVcp gene), respectively. More than 500 green, fertile, transgenic plants were regenerated from 36 transformed callus lines on bialaphos-containing medium; albino plants only were regenerated from 41 lines. T0 plants in 25 lines (three plants per line) were analyzed by DNA hybridization, and all contained bar. Most contained the same integration patterns for the introduced genes (bar, uidA, and the BYDVcp gene) as their parental callus lines. Transmission of the genes to T1 progeny was confirmed in the five families analyzed by DNA hybridization. A germination test of immature T1 embryos on bialaphos-containing medium was useful for selecting individuals that were actively expressing bar, although this was not a good indicator of the presence or absence of bar. Expression of bar in some progeny plants was indicated by resistance to the herbicide Basta. The T1 plants were in soil approximately 7 months after bombardment of the immature embryo. PMID:12232059
Realistic noise-tolerant randomness amplification using finite number of devices
Brandão, Fernando G. S. L.; Ramanathan, Ravishankar; Grudka, Andrzej; Horodecki, Karol; Horodecki, Michał; Horodecki, Paweł; Szarek, Tomasz; Wojewódka, Hanna
2016-01-01
Randomness is a fundamental concept, with implications from security of modern data systems, to fundamental laws of nature and even the philosophy of science. Randomness is called certified if it describes events that cannot be pre-determined by an external adversary. It is known that weak certified randomness can be amplified to nearly ideal randomness using quantum-mechanical systems. However, so far, it was unclear whether randomness amplification is a realistic task, as the existing proposals either do not tolerate noise or require an unbounded number of different devices. Here we provide an error-tolerant protocol using a finite number of devices for amplifying arbitrary weak randomness into nearly perfect random bits, which are secure against a no-signalling adversary. The correctness of the protocol is assessed by violating a Bell inequality, with the degree of violation determining the noise tolerance threshold. An experimental realization of the protocol is within reach of current technology. PMID:27098302
Realistic noise-tolerant randomness amplification using finite number of devices
NASA Astrophysics Data System (ADS)
Brandão, Fernando G. S. L.; Ramanathan, Ravishankar; Grudka, Andrzej; Horodecki, Karol; Horodecki, Michał; Horodecki, Paweł; Szarek, Tomasz; Wojewódka, Hanna
2016-04-01
Randomness is a fundamental concept, with implications from security of modern data systems, to fundamental laws of nature and even the philosophy of science. Randomness is called certified if it describes events that cannot be pre-determined by an external adversary. It is known that weak certified randomness can be amplified to nearly ideal randomness using quantum-mechanical systems. However, so far, it was unclear whether randomness amplification is a realistic task, as the existing proposals either do not tolerate noise or require an unbounded number of different devices. Here we provide an error-tolerant protocol using a finite number of devices for amplifying arbitrary weak randomness into nearly perfect random bits, which are secure against a no-signalling adversary. The correctness of the protocol is assessed by violating a Bell inequality, with the degree of violation determining the noise tolerance threshold. An experimental realization of the protocol is within reach of current technology.
The linking number and the writhe of uniform random walks and polygons in confined spaces
NASA Astrophysics Data System (ADS)
Panagiotou, E.; Millett, K. C.; Lambropoulou, S.
2010-01-01
Random walks and polygons are used to model polymers. In this paper we consider the extension of the writhe, self-linking number and linking number to open chains. We then study the average writhe, self-linking and linking number of random walks and polygons over the space of configurations as a function of their length. We show that the mean squared linking number, the mean squared writhe and the mean squared self-linking number of oriented uniform random walks or polygons of length n, in a convex confined space, are of the form O(n2). Moreover, for a fixed simple closed curve in a convex confined space, we prove that the mean absolute value of the linking number between this curve and a uniform random walk or polygon of n edges is of the form O(\\sqrt{n}) . Our numerical studies confirm those results. They also indicate that the mean absolute linking number between any two oriented uniform random walks or polygons, of n edges each, is of the form O(n). Equilateral random walks and polygons are used to model polymers in θ-conditions. We use numerical simulations to investigate how the self-linking and linking number of equilateral random walks scale with their length.
Non-random DNA fragmentation in next-generation sequencing
NASA Astrophysics Data System (ADS)
Poptsova, Maria S.; Il'Icheva, Irina A.; Nechipurenko, Dmitry Yu.; Panchenko, Larisa A.; Khodikov, Mingian V.; Oparina, Nina Y.; Polozov, Robert V.; Nechipurenko, Yury D.; Grokhovsky, Sergei L.
2014-03-01
Next Generation Sequencing (NGS) technology is based on cutting DNA into small fragments, and their massive parallel sequencing. The multiple overlapping segments termed ``reads'' are assembled into a contiguous sequence. To reduce sequencing errors, every genome region should be sequenced several dozen times. This sequencing approach is based on the assumption that genomic DNA breaks are random and sequence-independent. However, previously we showed that for the sonicated restriction DNA fragments the rates of double-stranded breaks depend on the nucleotide sequence. In this work we analyzed genomic reads from NGS data and discovered that fragmentation methods based on the action of the hydrodynamic forces on DNA, produce similar bias. Consideration of this non-random DNA fragmentation may allow one to unravel what factors and to what extent influence the non-uniform coverage of various genomic regions.
McFarland, Christopher D
2015-01-01
The Ziggurat Algorithm is a very fast rejection sampling method for generating PseudoRandom Numbers (PRNs) from statistical distributions. In the algorithm, rectangular sampling domains are layered on top of each other (resembling a ziggurat) to encapsulate the desired probability density function. Random values within these layers are sampled and then returned if they lie beneath the graph of the probability density function. Here, we present an implementation where ziggurat layers reside completely beneath the probability density function, thereby eliminating the need for any rejection test within the ziggurat layers. In the new algorithm, small overhanging segments of probability density remain to the right of each ziggurat layer, which can be efficiently sampled with triangularly-shaped sampling domains. Median runtimes of the new algorithm for exponential and normal variates is reduced to 58% and 53% respectively (collective range: 41–93%). An accessible C library, along with extensions into Python and MATLAB/Octave are provided. PMID:27041780
Microcomputers: Instrument Generation Software. Evaluation Guides. Guide Number 11.
ERIC Educational Resources Information Center
Gray, Peter J.
Designed to assist evaluators in selecting the appropriate software for the generation of various data collection instruments, this guide discusses such key program characteristics as text entry, item storage and manipulation, item retrieval, and printing. Some characteristics of a good instrument generation program are discussed; these include…
Shteingart, Hanan; Loewenstein, Yonatan
2016-01-01
There is a long history of experiments in which participants are instructed to generate a long sequence of binary random numbers. The scope of this line of research has shifted over the years from identifying the basic psychological principles and/or the heuristics that lead to deviations from randomness, to one of predicting future choices. In this paper, we used generalized linear regression and the framework of Reinforcement Learning in order to address both points. In particular, we used logistic regression analysis in order to characterize the temporal sequence of participants’ choices. Surprisingly, a population analysis indicated that the contribution of the most recent trial has only a weak effect on behavior, compared to more preceding trials, a result that seems irreconcilable with standard sequential effects that decay monotonously with the delay. However, when considering each participant separately, we found that the magnitudes of the sequential effect are a monotonous decreasing function of the delay, yet these individual sequential effects are largely averaged out in a population analysis because of heterogeneity. The substantial behavioral heterogeneity in this task is further demonstrated quantitatively by considering the predictive power of the model. We show that a heterogeneous model of sequential dependencies captures the structure available in random sequence generation. Finally, we show that the results of the logistic regression analysis can be interpreted in the framework of reinforcement learning, allowing us to compare the sequential effects in the random sequence generation task to those in an operant learning task. We show that in contrast to the random sequence generation task, sequential effects in operant learning are far more homogenous across the population. These results suggest that in the random sequence generation task, different participants adopt different cognitive strategies to suppress sequential dependencies when
Automatic Generation of Randomized Trial Sequences for Priming Experiments
Ihrke, Matthias; Behrendt, Jörg
2011-01-01
In most psychological experiments, a randomized presentation of successive displays is crucial for the validity of the results. For some paradigms, this is not a trivial issue because trials are interdependent, e.g., priming paradigms. We present a software that automatically generates optimized trial sequences for (negative-) priming experiments. Our implementation is based on an optimization heuristic known as genetic algorithms that allows for an intuitive interpretation due to its similarity to natural evolution. The program features a graphical user interface that allows the user to generate trial sequences and to interactively improve them. The software is based on freely available software and is released under the GNU General Public License. PMID:22007178
Nonquadratic Variation of the Blum Blum Shub Pseudorandom Number Generator
2016-09-01
maximum 200 words) Cryptography is essential for secure online communications. Many different types of ciphers are implemented in modern-day... cryptography , but they all have one common factor. All ciphers require a source of randomness, which makes them unpre- dictable. One such source of this...Martinsen Second Reader Craig Rasmussen Chair, Department of Applied Mathematics iii THIS PAGE INTENTIONALLY LEFT BLANK iv ABSTRACT Cryptography is
Making heads or tails of probability: an experiment with random generators.
Morsanyi, Kinga; Handley, Simon J; Serpell, Sylvie
2013-09-01
The equiprobability bias is a tendency for individuals to think of probabilistic events as 'equiprobable' by nature, and to judge outcomes that occur with different probabilities as equally likely. The equiprobability bias has been repeatedly found to be related to formal education in statistics, and it is claimed to be based on a misunderstanding of the concept of randomness. The aim of the present study was to examine whether experimenting with random generators would decrease the equiprobability bias. The participants were 108 psychology students whose performance was measured either immediately after taking part in a training session (n= 55), or without doing any training exercises (n= 53). The training session consisted of four activities. These included generating random sequences of events, and learning about the law of large numbers. Subsequently, the participants were tested on a series of equiprobability problems, and a number of other problems with similar structure and content. The results indicated that the training successfully decreased the equiprobability bias. However, this effect was moderated by participants' cognitive ability (i.e., higher ability participants benefitted from the training more than participants with lower cognitive ability). Finally, the training session had the unexpected side effect of increasing students' susceptibility to the representativeness heuristic. Experimenting with random generators has a positive effect on students' general understanding of probability, but the same time it might increase their susceptibility to certain biases (especially, to the representativeness heuristic). These findings have important implications for using training methods to improve probabilistic reasoning performance. © 2012 The British Psychological Society.
Raw and Central Moments of Binomial Random Variables via Stirling Numbers
ERIC Educational Resources Information Center
Griffiths, Martin
2013-01-01
We consider here the problem of calculating the moments of binomial random variables. It is shown how formulae for both the raw and the central moments of such random variables may be obtained in a recursive manner utilizing Stirling numbers of the first kind. Suggestions are also provided as to how students might be encouraged to explore this…
Raw and Central Moments of Binomial Random Variables via Stirling Numbers
ERIC Educational Resources Information Center
Griffiths, Martin
2013-01-01
We consider here the problem of calculating the moments of binomial random variables. It is shown how formulae for both the raw and the central moments of such random variables may be obtained in a recursive manner utilizing Stirling numbers of the first kind. Suggestions are also provided as to how students might be encouraged to explore this…
Kanter, Ido; Butkovski, Maria; Peleg, Yitzhak; Zigzag, Meital; Aviad, Yaara; Reidler, Igor; Rosenbluh, Michael; Kinzel, Wolfgang
2010-08-16
Random bit generators (RBGs) constitute an important tool in cryptography, stochastic simulations and secure communications. The later in particular has some difficult requirements: high generation rate of unpredictable bit strings and secure key-exchange protocols over public channels. Deterministic algorithms generate pseudo-random number sequences at high rates, however, their unpredictability is limited by the very nature of their deterministic origin. Recently, physical RBGs based on chaotic semiconductor lasers were shown to exceed Gbit/s rates. Whether secure synchronization of two high rate physical RBGs is possible remains an open question. Here we propose a method, whereby two fast RBGs based on mutually coupled chaotic lasers, are synchronized. Using information theoretic analysis we demonstrate security against a powerful computational eavesdropper, capable of noiseless amplification, where all parameters are publicly known. The method is also extended to secure synchronization of a small network of three RBGs.
Response selection in dual task paradigms: observations from random generation tasks.
Dirnberger, Georg; Jahanshahi, Marjan
2010-03-01
Performance of attention-demanding tasks is worse if two tasks are carried out simultaneously than if each of the tasks is performed alone. Our aim was to determine whether these 'dual task costs' can be attributed to mechanisms on a supra-trial level such as switching of limited resources between trials or concurrent breakdown of supervisory functions, or to mechanisms effective within each trial such as demands of response selection. Twenty healthy volunteers performed verbal random number generation (RNG) and random movement generation (RMG) at three different rates. For each rate, both tasks were examined once in a single task condition and once in a dual task condition. Results showed that performance (quality of randomness) in each random generation task (RNG/RMG) was reduced at faster rates and impaired by concurrent performance of a secondary random generation task. In the dual task condition, transient increase or decrease of bias in one random generation task during any short interval was not associated with concurrent increase or decrease of bias in the other task. In conclusion, the fact that during dual task performance transient bias in one task was not associated with concurrent improvement of performance in the other task indicates that alternation of supervisory control or attentional resources from one to the other task does not mediate the observed dual task costs. Resources of the central executive are not re-allocated or 'switched' from one to the other task. Dual task costs may result from mechanisms effective within each trial such as the demands of response selection.
Generation of Random Particle Packings for Discrete Element Models
NASA Astrophysics Data System (ADS)
Abe, S.; Weatherley, D.; Ayton, T.
2012-04-01
An important step in the setup process of Discrete Element Model (DEM) simulations is the generation of a suitable particle packing. There are quite a number of properties such a granular material specimen should ideally have, such as high coordination number, isotropy, the ability to fill arbitrary bounding volumes and the absence of locked-in stresses. An algorithm which is able to produce specimens fulfilling these requirements is the insertion based sphere packing algorithm originally proposed by Place and Mora, 2001 [2] and extended in this work. The algorithm works in two stages. First a number of "seed" spheres are inserted into the bounding volume. In the second stage the gaps between the "seed" spheres are filled by inserting new spheres in a way so they have D+1 (i.e. 3 in 2D, 4 in 3D) touching contacts with either other spheres or the boundaries of the enclosing volume. Here we present an implementation of the algorithm and a systematic statistical analysis of the generated sphere packings. The analysis of the particle radius distribution shows that they follow a power-law with an exponent ≈ D (i.e. ≈3 for a 3D packing and ≈2 for 2D). Although the algorithm intrinsically guarantees coordination numbers of at least 4 in 3D and 3 in 2D, the coordination numbers realized in the generated packings can be significantly higher, reaching beyond 50 if the range of particle radii is sufficiently large. Even for relatively small ranges of particle sizes (e.g. Rmin = 0.5Rmax) the maximum coordination number may exceed 10. The degree of isotropy of the generated sphere packing is also analysed in both 2D and 3D, by measuring the distribution of orientations of vectors joining the centres of adjacent particles. If the range of particle sizes is small, the packing algorithm yields moderate anisotropy approaching that expected for a face-centred cubic packing of equal-sized particles. However, once Rmin < 0.3Rmax a very high degree of isotropy is demonstrated in
On-chip generation of heralded photon-number states
NASA Astrophysics Data System (ADS)
Vergyris, Panagiotis; Meany, Thomas; Lunghi, Tommaso; Sauder, Gregory; Downes, James; Steel, M. J.; Withford, Michael J.; Alibart, Olivier; Tanzilli, Sébastien
2016-10-01
Beyond the use of genuine monolithic integrated optical platforms, we report here a hybrid strategy enabling on-chip generation of configurable heralded two-photon states. More specifically, we combine two different fabrication techniques, i.e., non-linear waveguides on lithium niobate for efficient photon-pair generation and femtosecond-laser-direct-written waveguides on glass for photon manipulation. Through real-time device manipulation capabilities, a variety of path-coded heralded two-photon states can be produced, ranging from product to entangled states. Those states are engineered with high levels of purity, assessed by fidelities of 99.5 ± 8% and 95.0 ± 8%, respectively, obtained via quantum interferometric measurements. Our strategy therefore stands as a milestone for further exploiting entanglement-based protocols, relying on engineered quantum states, and enabled by scalable and compatible photonic circuits.
On-chip generation of heralded photon-number states
Vergyris, Panagiotis; Meany, Thomas; Lunghi, Tommaso; Sauder, Gregory; Downes, James; Steel, M. J.; Withford, Michael J.; Alibart, Olivier; Tanzilli, Sébastien
2016-01-01
Beyond the use of genuine monolithic integrated optical platforms, we report here a hybrid strategy enabling on-chip generation of configurable heralded two-photon states. More specifically, we combine two different fabrication techniques, i.e., non-linear waveguides on lithium niobate for efficient photon-pair generation and femtosecond-laser-direct-written waveguides on glass for photon manipulation. Through real-time device manipulation capabilities, a variety of path-coded heralded two-photon states can be produced, ranging from product to entangled states. Those states are engineered with high levels of purity, assessed by fidelities of 99.5 ± 8% and 95.0 ± 8%, respectively, obtained via quantum interferometric measurements. Our strategy therefore stands as a milestone for further exploiting entanglement-based protocols, relying on engineered quantum states, and enabled by scalable and compatible photonic circuits. PMID:27775062
Emergence of a 'visual number sense' in hierarchical generative models.
Stoianov, Ivilin; Zorzi, Marco
2012-01-08
Numerosity estimation is phylogenetically ancient and foundational to human mathematical learning, but its computational bases remain controversial. Here we show that visual numerosity emerges as a statistical property of images in 'deep networks' that learn a hierarchical generative model of the sensory input. Emergent numerosity detectors had response profiles resembling those of monkey parietal neurons and supported numerosity estimation with the same behavioral signature shown by humans and animals.
NASA Astrophysics Data System (ADS)
Xu, Peifeng; Shi, Kai; Sun, Yuxin; Zhua, Huangqiu
2017-05-01
Dual rotor permanent magnet (DRPM) wind power generator using ferrite magnets has the advantages of low cost, high efficiency, and high torque density. How to further improve the performance and reduce the cost of the machine by proper choice of pole number and slot number is an important problem to be solved when performing preliminarily design a DRPM wind generator. This paper presents a comprehensive performance comparison of a DRPM wind generator using ferrite magnets with different slot and pole number combinations. The main winding factors are calculated by means of the star of slots. Under the same machine volume and ferrite consumption, the flux linkage, back-electromotive force (EMF), cogging torque, output torque, torque pulsation, and losses are investigated and compared using finite element analysis (FEA). The results show that the slot and pole number combinations have an important impact on the generator properties.
Generating Random Earthquake Events for Probabilistic Tsunami Hazard Assessment
NASA Astrophysics Data System (ADS)
LeVeque, Randall J.; Waagan, Knut; González, Frank I.; Rim, Donsub; Lin, Guang
2016-12-01
To perform probabilistic tsunami hazard assessment for subduction zone earthquakes, it is necessary to start with a catalog of possible future events along with the annual probability of occurrence, or a probability distribution of such events that can be easily sampled. For near-field events, the distribution of slip on the fault can have a significant effect on the resulting tsunami. We present an approach to defining a probability distribution based on subdividing the fault geometry into many subfaults and prescribing a desired covariance matrix relating slip on one subfault to slip on any other subfault. The eigenvalues and eigenvectors of this matrix are then used to define a Karhunen-Loève expansion for random slip patterns. This is similar to a spectral representation of random slip based on Fourier series but conforms to a general fault geometry. We show that only a few terms in this series are needed to represent the features of the slip distribution that are most important in tsunami generation, first with a simple one-dimensional example where slip varies only in the down-dip direction and then on a portion of the Cascadia Subduction Zone.
Theory of second harmonic generation in randomly oriented species
NASA Astrophysics Data System (ADS)
Andrews, David L.; Allcock, Philip; Demidov, Andrey A.
1995-01-01
It is well known that second harmonic generation (SHG) is a process forbidden within atomic and molecular fluids. Nonetheless recent experimental observations of second harmonic evolution in suspensions of randomly oriented Halobacterium halobium purple membranes have raised new questions about the precise criteria which determine prohibition of the second harmonic. To address the problem a theoretical framework for SHG is developed that specifically deals with molecular systems, and is therefore cast in terms of molecular properties with more regard to the influence of the local structure. This contrasts with the classical approach based on bulk susceptibilities, which has not proved adequate to explain the conflicting experimental results. By properly formulating the detailed procedure for dealing with the necessary orientational averages, the present theory discloses a relationship between the coherent process of second harmonic generation and a directed component of its incoherent counterpart, hyper-Rayleigh scattering. Inter alia, the theory explains the SHG detected in purple membrane suspensions. The polarisation features of the harmonic evolution are also considered more generally, and in particular it is shown that the SHG signal will persist under conditions of circularly polarised pumping. This specific polarisation feature will allow experimental validation of the theory.
Internal wave generation by tidal flow over random topography
NASA Astrophysics Data System (ADS)
Zhao, Jiajun; Zhang, Likun; Swinney, Harry
2015-11-01
The irregularity of oceanic topography plays a critical role in determining the power in internal waves generated by tidal flow over the seafloor. We conduct numerical simulations (for a fluid with a constant buoyancy frequency) for different synthetic random topographies. For topography with small rms height Hrms and small slopes the simulations yield a quadratic dependence of the power on Hrms, in accord with linear theory. However, for tall topography with steep slopes the internal wave power is found to vary linearly with Hrms. The transition from quadratic to linear scaling of the radiated internal wave power on Hrms occurs when the ``valley slope'' exceeds the internal wave slope. (The valley slope, to be defined in this talk, characterizes the maximum slope of topography between adjacent peaks.) The simulations also reveal that the radiated power saturates with increasing topographic resolution, as conjectured in previous studies. The present results should be helpful in improving estimates of the total internal wave power generated by the world's oceans.
The intersection numbers of the p-spin curves from random matrix theory
NASA Astrophysics Data System (ADS)
Brézin, E.; Hikami, S.
2013-02-01
The intersection numbers of p-spin curves are computed through correlation functions of Gaussian ensembles of random matrices in an external matrix source. The p-dependence of intersection numbers is determined as polynomial in p; the large p behavior is also considered. The analytic continuation of intersection numbers to negative values of p is discussed in relation to SL(2,R)/U(1) black hole sigma model.
NASA Astrophysics Data System (ADS)
Argollo de Menezes, Marcio; Brigatti, Edgardo; Schwämmle, Veit
2013-08-01
Microbiological systems evolve to fulfil their tasks with maximal efficiency. The immune system is a remarkable example, where the distinction between self and non-self is made by means of molecular interaction between self-proteins and antigens, triggering affinity-dependent systemic actions. Specificity of this binding and the infinitude of potential antigenic patterns call for novel mechanisms to generate antibody diversity. Inspired by this problem, we develop a genetic algorithm where agents evolve their strings in the presence of random antigenic strings and reproduce with affinity-dependent rates. We ask what is the best strategy to generate diversity if agents can rearrange their strings a finite number of times. We find that endowing each agent with an inheritable cellular automaton rule for performing rearrangements makes the system more efficient in pattern-matching than if transformations are totally random. In the former implementation, the population evolves to a stationary state where agents with different automata rules coexist.
The expected number of distinct sites visited by N biased random walks in one dimension
NASA Astrophysics Data System (ADS)
Larralde, Hernan; Weiss, George H.; Eugene Stanley, H.
1994-09-01
We calculate the asymptotic form of the expected number of distinct sites visited by N random walkers moving independently in one dimension. It is shown that to lowest order and at long times, the leading term in the asymptotic result is that found for the random walk of a single biased particle, which implies that the bias is strong enough a factor to dominate the many-body effects in that regime. The lowest order correction term contains the many-body contribution. This is essentially the result for the unbiased random walk.
Using common random numbers in health care cost-effectiveness simulation modeling.
Murphy, Daniel R; Klein, Robert W; Smolen, Lee J; Klein, Timothy M; Roberts, Stephen D
2013-08-01
To identify the problem of separating statistical noise from treatment effects in health outcomes modeling and analysis. To demonstrate the implementation of one technique, common random numbers (CRNs), and to illustrate the value of CRNs to assess costs and outcomes under uncertainty. A microsimulation model was designed to evaluate osteoporosis treatment, estimating cost and utility measures for patient cohorts at high risk of osteoporosis-related fractures. Incremental cost-effectiveness ratios (ICERs) were estimated using a full implementation of CRNs, a partial implementation of CRNs, and no CRNs. A modification to traditional probabilistic sensitivity analysis (PSA) was used to determine how variance reduction can impact a decision maker's view of treatment efficacy and costs. The full use of CRNs provided a 93.6 percent reduction in variance compared to simulations not using the technique. The use of partial CRNs provided a 5.6 percent reduction. The PSA results using full CRNs demonstrated a substantially tighter range of cost-benefit outcomes for teriparatide usage than the cost-benefits generated without the technique. CRNs provide substantial variance reduction for cost-effectiveness studies. By reducing variability not associated with the treatment being evaluated, CRNs provide a better understanding of treatment effects and risks. © Health Research and Educational Trust.
Using Common Random Numbers in Health Care Cost-Effectiveness Simulation Modeling
Murphy, Daniel R; Klein, Robert W; Smolen, Lee J; Klein, Timothy M; Roberts, Stephen D
2013-01-01
Objectives To identify the problem of separating statistical noise from treatment effects in health outcomes modeling and analysis. To demonstrate the implementation of one technique, common random numbers (CRNs), and to illustrate the value of CRNs to assess costs and outcomes under uncertainty. Methods A microsimulation model was designed to evaluate osteoporosis treatment, estimating cost and utility measures for patient cohorts at high risk of osteoporosis-related fractures. Incremental cost-effectiveness ratios (ICERs) were estimated using a full implementation of CRNs, a partial implementation of CRNs, and no CRNs. A modification to traditional probabilistic sensitivity analysis (PSA) was used to determine how variance reduction can impact a decision maker's view of treatment efficacy and costs. Results The full use of CRNs provided a 93.6 percent reduction in variance compared to simulations not using the technique. The use of partial CRNs provided a 5.6 percent reduction. The PSA results using full CRNs demonstrated a substantially tighter range of cost-benefit outcomes for teriparatide usage than the cost-benefits generated without the technique. Conclusions CRNs provide substantial variance reduction for cost-effectiveness studies. By reducing variability not associated with the treatment being evaluated, CRNs provide a better understanding of treatment effects and risks. PMID:23402573
Keeping the noise down: common random numbers for disease simulation modeling.
Stout, Natasha K; Goldie, Sue J
2008-12-01
Disease simulation models are used to conduct decision analyses of the comparative benefits and risks associated with preventive and treatment strategies. To address increasing model complexity and computational intensity, modelers use variance reduction techniques to reduce stochastic noise and improve computational efficiency. One technique, common random numbers, further allows modelers to conduct counterfactual-like analyses with direct computation of statistics at the individual level. This technique uses synchronized random numbers across model runs to induce correlation in model output thereby making differences easier to distinguish as well as simulating identical individuals across model runs. We provide a tutorial introduction and demonstrate the application of common random numbers in an individual-level simulation model of the epidemiology of breast cancer.
Keeping the Noise Down: Common Random Numbers for Disease Simulation Modeling
Stout, Natasha K.; Goldie, Sue J.
2009-01-01
Disease simulation models are used to conduct decision analyses of the comparative benefits and risks associated with preventive and treatment strategies. To address increasing model complexity and computational intensity, modelers use variance reduction techniques to reduce stochastic noise and improve computational efficiency. One technique, common random numbers, further allows modelers to conduct counterfactual-like analyses with direct computation of statistics at the individual level. This technique uses synchronized random numbers across model runs to induce correlation in model output thereby making differences easier to distinguish as well as simulating identical individuals across model runs. We provide a tutorial introduction and demonstrate the application of common random numbers in an individual-level simulation model of the epidemiology of breast cancer. PMID:18998599
Alamino, R C; Saad, D
2008-06-01
Using methods of statistical physics, we study the average number and kernel size of general sparse random matrices over Galois fields GF(q) , with a given connectivity profile, in the thermodynamical limit of large matrices. We introduce a mapping of GF(q) matrices onto spin systems using the representation of the cyclic group of order q as the q th complex roots of unity. This representation facilitates the derivation of the average kernel size of random matrices using the replica approach, under the replica-symmetric ansatz, resulting in saddle point equations for general connectivity distributions. Numerical solutions are then obtained for particular cases by population dynamics. Similar techniques also allow us to obtain an expression for the exact and average numbers of random matrices for any general connectivity profile. We present numerical results for particular distributions.
NASA Astrophysics Data System (ADS)
Urano, Ryo; Okamoto, Yuko
2015-12-01
We propose a replica-exchange method (REM) which does not use pseudo random numbers. For this purpose, we first give a conditional probability for Gibbs sampling replica-exchange method (GSREM) based on the heat bath method. In GSREM, replica exchange is performed by conditional probability based on the weight of states using pseudo random numbers. From the conditional probability, we propose a new method called deterministic replica-exchange method (DETREM) that produces thermal equilibrium distribution based on a differential equation instead of using pseudo random numbers. This method satisfies the detailed balance condition using a conditional probability of Gibbs heat bath method and thus results can reproduce the Boltzmann distribution within the condition of the probability. We confirmed that the equivalent results were obtained by REM and DETREM with two-dimensional Ising model. DETREM can avoid problems of choice of seeds in pseudo random numbers for parallel computing of REM and gives analytic method for REM using a differential equation.
Laws of large numbers for q-dependent random variables and nonextensive statistical mechanics
NASA Astrophysics Data System (ADS)
Trindade, Marco A. S.
2017-06-01
In this work, we prove a weak law and a strong law of large numbers through the concept of q-product for dependent random variables, in the context of nonextensive statistical mechanics. Applications for the consistency of estimators are presented and connections with stochastic processes are discussed.
NASA Astrophysics Data System (ADS)
Reznik, A. L.; Tuzikov, A. V.; Solov'ev, A. A.; Torgov, A. V.
2016-11-01
Original codes and combinatorial-geometrical computational schemes are presented, which are developed and applied for finding exact analytical formulas that describe the probability of errorless readout of random point images recorded by a scanning aperture with a limited number of threshold levels. Combinatorial problems encountered in the course of the study and associated with the new generalization of Catalan numbers are formulated and solved. An attempt is made to find the explicit analytical form of these numbers, which is, on the one hand, a necessary stage of solving the basic research problem and, on the other hand, an independent self-consistent problem.
rMotifGen: random motif generator for DNA and protein sequences.
Rouchka, Eric C; Hardin, C Timothy
2007-08-07
Detection of short, subtle conserved motif regions within a set of related DNA or amino acid sequences can lead to discoveries about important regulatory domains such as transcription factor and DNA binding sites as well as conserved protein domains. In order to help assess motif detection algorithms on motifs with varying properties and levels of conservation, we have developed a computational tool, rMotifGen, with the sole purpose of generating a number of random DNA or protein sequences containing short sequence motifs. Each motif consensus can be user-defined, randomly generated, or created from a position-specific scoring matrix (PSSM). Insertions and mutations within these motifs are created according to user-defined parameters and substitution matrices. The resulting sequences can be helpful in mutational simulations and in testing the limits of motif detection algorithms. Two implementations of rMotifGen have been created, one providing a graphical user interface (GUI) for random motif construction, and the other serving as a command line interface. The second implementation has the added advantages of platform independence and being able to be called in a batch mode. rMotifGen was used to construct sample sets of sequences containing DNA motifs and amino acid motifs that were then tested against the Gibbs sampler and MEME packages. rMotifGen provides an efficient and convenient method for creating random DNA or amino acid sequences with a variable number of motifs, where the instance of each motif can be incorporated using a position-specific scoring matrix (PSSM) or by creating an instance mutated from its corresponding consensus using an evolutionary model based on substitution matrices. rMotifGen is freely available at: http://bioinformatics.louisville.edu/brg/rMotifGen/.
rMotifGen: random motif generator for DNA and protein sequences
Rouchka, Eric C; Hardin, C Timothy
2007-01-01
Background Detection of short, subtle conserved motif regions within a set of related DNA or amino acid sequences can lead to discoveries about important regulatory domains such as transcription factor and DNA binding sites as well as conserved protein domains. In order to help assess motif detection algorithms on motifs with varying properties and levels of conservation, we have developed a computational tool, rMotifGen, with the sole purpose of generating a number of random DNA or protein sequences containing short sequence motifs. Each motif consensus can be user-defined, randomly generated, or created from a position-specific scoring matrix (PSSM). Insertions and mutations within these motifs are created according to user-defined parameters and substitution matrices. The resulting sequences can be helpful in mutational simulations and in testing the limits of motif detection algorithms. Results Two implementations of rMotifGen have been created, one providing a graphical user interface (GUI) for random motif construction, and the other serving as a command line interface. The second implementation has the added advantages of platform independence and being able to be called in a batch mode. rMotifGen was used to construct sample sets of sequences containing DNA motifs and amino acid motifs that were then tested against the Gibbs sampler and MEME packages. Conclusion rMotifGen provides an efficient and convenient method for creating random DNA or amino acid sequences with a variable number of motifs, where the instance of each motif can be incorporated using a position-specific scoring matrix (PSSM) or by creating an instance mutated from its corresponding consensus using an evolutionary model based on substitution matrices. rMotifGen is freely available at: . PMID:17683637
Hansen, Marie J; Rasmussen, Nana Ø; Chung, Grace
2008-01-01
We have developed a method for extracting the number of trial participants from abstracts describing randomized controlled trials (RCTs); the number of trial participants may be an indication of the reliability of the trial. The method depends on statistical natural language processing. The number of interest was determined by a binary supervised classification based on a support vector machine algorithm. The method was trialled on 223 abstracts in which the number of trial participants was identified manually to act as a gold standard. Automatic extraction resulted in 2 false-positive and 19 false-negative classifications. The algorithm was capable of extracting the number of trial participants with an accuracy of 97% and an F-measure of 0.84. The algorithm may improve the selection of relevant articles in regard to question-answering, and hence may assist in decision-making.
ERIC Educational Resources Information Center
Kiliç, Çigdem
2017-01-01
In that current study, pattern conversion ability of 25 pre-service mathematics teachers (producing figural patterns following number patterns) was investigated. During the study participants were asked to generate figural patterns based on those number patterns. The results of the study indicate that many participants could generate different…
A stochastic basis to the spatially uniform distribution of randomly generated Ionian paterae
NASA Astrophysics Data System (ADS)
Shoji, D.; Hussmann, H.
2016-10-01
Due to its tidally heated interior, Io is a geologically very active satellite that bears many volcanic features. It is observed that the mean nearest neighbor distance of each volcanic feature, called a patera, is larger than that of a random distribution, which implies that the spatial distribution of paterae is uniform rather than random. However, it is uncertain how the paterae are organized into a uniform distribution. We suggest the mechanism of Io's uniformly distributed paterae considering localized obliteration of old features. Instead of geological modeling, we performed stochastic simulations and statistical analyses for the obliteration of quiescent paterae. Monte Carlo calculations with Gaussian obliteration probability show that if the width of obliteration probability is approximately 80 km and the volcanic generation rate is ˜5.0 × 10-6 km-2 Ma-1, uniform distribution and the observed number density of paterae are attained at the 2σ level on a time scale of approximately 6 Myr. With this generation rate and width of the obliteration probability, the averaged distance of one patera to the nearest patera (mean nearest neighbor distance) is approximately 200 km, which is consistent with the observed value. The uniformity of the distribution is maintained once it is achieved. On regional scales, Io's paterae would naturally evolve from random into uniform distributions by the obliteration of old and quiescent features.
Li, Xiao-Zhou; Li, Song-Sui; Zhuang, Jun-Ping; Chan, Sze-Chun
2015-09-01
A semiconductor laser with distributed feedback from a fiber Bragg grating (FBG) is investigated for random bit generation (RBG). The feedback perturbs the laser to emit chaotically with the intensity being sampled periodically. The samples are then converted into random bits by a simple postprocessing of self-differencing and selecting bits. Unlike a conventional mirror that provides localized feedback, the FBG provides distributed feedback which effectively suppresses the information of the round-trip feedback delay time. Randomness is ensured even when the sampling period is commensurate with the feedback delay between the laser and the grating. Consequently, in RBG, the FBG feedback enables continuous tuning of the output bit rate, reduces the minimum sampling period, and increases the number of bits selected per sample. RBG is experimentally investigated at a sampling period continuously tunable from over 16 ns down to 50 ps, while the feedback delay is fixed at 7.7 ns. By selecting 5 least-significant bits per sample, output bit rates from 0.3 to 100 Gbps are achieved with randomness examined by the National Institute of Standards and Technology test suite.
Quantum cryptography using coherent states: Randomized encryption and key generation
NASA Astrophysics Data System (ADS)
Corndorf, Eric
With the advent of the global optical-telecommunications infrastructure, an increasing number of individuals, companies, and agencies communicate information with one another over public networks or physically-insecure private networks. While the majority of the traffic flowing through these networks requires little or no assurance of secrecy, the same cannot be said for certain communications between banks, between government agencies, within the military, and between corporations. In these arenas, the need to specify some level of secrecy in communications is a high priority. While the current approaches to securing sensitive information (namely the public-key-cryptography infrastructure and deterministic private-key ciphers like AES and 3DES) seem to be cryptographically strong based on empirical evidence, there exist no mathematical proofs of secrecy for any widely deployed cryptosystem. As an example, the ubiquitous public-key cryptosystems infer all of their secrecy from the assumption that factoring of the product of two large primes is necessarily time consuming---something which has not, and perhaps cannot, be proven. Since the 1980s, the possibility of using quantum-mechanical features of light as a physical mechanism for satisfying particular cryptographic objectives has been explored. This research has been fueled by the hopes that cryptosystems based on quantum systems may provide provable levels of secrecy which are at least as valid as quantum mechanics itself. Unfortunately, the most widely considered quantum-cryptographic protocols (BB84 and the Ekert protocol) have serious implementation problems. Specifically, they require quantum-mechanical states which are not readily available, and they rely on unproven relations between intrusion-level detection and the information available to an attacker. As a result, the secrecy level provided by these experimental implementations is entirely unspecified. In an effort to provably satisfy the cryptographic
Large Deviation Function for the Number of Eigenvalues of Sparse Random Graphs Inside an Interval
NASA Astrophysics Data System (ADS)
Metz, Fernando L.; Pérez Castillo, Isaac
2016-09-01
We present a general method to obtain the exact rate function Ψ[a ,b ](k ) controlling the large deviation probability Prob[IN[a ,b ]=k N ]≍e-N Ψ[a ,b ](k ) that an N ×N sparse random matrix has IN[a ,b ]=k N eigenvalues inside the interval [a ,b ]. The method is applied to study the eigenvalue statistics in two distinct examples: (i) the shifted index number of eigenvalues for an ensemble of Erdös-Rényi graphs and (ii) the number of eigenvalues within a bounded region of the spectrum for the Anderson model on regular random graphs. A salient feature of the rate function in both cases is that, unlike rotationally invariant random matrices, it is asymmetric with respect to its minimum. The asymmetric character depends on the disorder in a way that is compatible with the distinct eigenvalue statistics corresponding to localized and delocalized eigenstates. The results also show that the level compressibility κ2/κ1 for the Anderson model on a regular graph satisfies 0 <κ2/κ1<1 in the bulk regime, in contrast with the behavior found in Gaussian random matrices. Our theoretical findings are thoroughly compared to numerical diagonalization in both cases, showing a reasonable good agreement.
Large Deviation Function for the Number of Eigenvalues of Sparse Random Graphs Inside an Interval.
Metz, Fernando L; Pérez Castillo, Isaac
2016-09-02
We present a general method to obtain the exact rate function Ψ_{[a,b]}(k) controlling the large deviation probability Prob[I_{N}[a,b]=kN]≍e^{-NΨ_{[a,b]}(k)} that an N×N sparse random matrix has I_{N}[a,b]=kN eigenvalues inside the interval [a,b]. The method is applied to study the eigenvalue statistics in two distinct examples: (i) the shifted index number of eigenvalues for an ensemble of Erdös-Rényi graphs and (ii) the number of eigenvalues within a bounded region of the spectrum for the Anderson model on regular random graphs. A salient feature of the rate function in both cases is that, unlike rotationally invariant random matrices, it is asymmetric with respect to its minimum. The asymmetric character depends on the disorder in a way that is compatible with the distinct eigenvalue statistics corresponding to localized and delocalized eigenstates. The results also show that the level compressibility κ_{2}/κ_{1} for the Anderson model on a regular graph satisfies 0<κ_{2}/κ_{1}<1 in the bulk regime, in contrast with the behavior found in Gaussian random matrices. Our theoretical findings are thoroughly compared to numerical diagonalization in both cases, showing a reasonable good agreement.
Some recent variations on the expected number of distinct sites visited by an n-step random walk
NASA Astrophysics Data System (ADS)
Weiss, George H.; Dayan, Ido; Havlin, Shlomo; Kiefer, James E.; Larralde, Hernan; Stanley, H. Eugene; Trunfio, Paul
1992-12-01
Asymptotic forms for the expected number of distinct sites visited by an n-step random walk, being calculable for many random walks, have been used in a number of analyses of physical models. We describe three recent extensions of the problem, the first replacing the single random walker by N→∞ random walkers, the second to the study of a random walk in the presence of a trapping site, and the third to a random walk in the presence of a trapping hyperplane.
Oracle inequalities for SVMs that are based on random entropy numbers
Steinwart, Ingo
2009-01-01
In this paper we present a new technique for bounding local Rademacher averages of function classes induced by a loss function and a reproducing kernel Hilbert space (RKHS). At the heart of this technique lies the observation that certain expectations of random entropy numbers can be bounded by the eigenvalues of the integral operator associated to the RKHS. We then work out the details of the new technique by establishing two new oracle inequalities for SVMs, which complement and generalize orevious results.
Wave propagation in randomly stratified media and the law of large numbers
NASA Astrophysics Data System (ADS)
Kotulski, Z.
1992-10-01
The propagation of scalar harmonic waves through a randomly stratified slab is investigated. The transition matrix method is applied for the analysis of the problem. To obtain the effective parameters of the material of the slab the law of large numbers for non-commuting products is applied. The results are illustrated with the numerical example of the propagation of elastic waves in steel-titanium laminate in an aluminium environment.
Random-effects meta-analysis: the number of studies matters.
Guolo, Annamaria; Varin, Cristiano
2017-06-01
This paper investigates the impact of the number of studies on meta-analysis and meta-regression within the random-effects model framework. It is frequently neglected that inference in random-effects models requires a substantial number of studies included in meta-analysis to guarantee reliable conclusions. Several authors warn about the risk of inaccurate results of the traditional DerSimonian and Laird approach especially in the common case of meta-analysis involving a limited number of studies. This paper presents a selection of likelihood and non-likelihood methods for inference in meta-analysis proposed to overcome the limitations of the DerSimonian and Laird procedure, with a focus on the effect of the number of studies. The applicability and the performance of the methods are investigated in terms of Type I error rates and empirical power to detect effects, according to scenarios of practical interest. Simulation studies and applications to real meta-analyses highlight that it is not possible to identify an approach uniformly superior to alternatives. The overall recommendation is to avoid the DerSimonian and Laird method when the number of meta-analysis studies is modest and prefer a more comprehensive procedure that compares alternative inferential approaches. R code for meta-analysis according to all of the inferential methods examined in the paper is provided.
Carmody, F; Grant, A; Somchiwong, M
1986-01-01
A new design of vacuum extractor cup--'the New Generation cup'--has recently been introduced into clinical practice. Its major modification is a traction cord which passes around the rim of the cup for 180 degrees and is free to slide within the rim. Claims that this design 'enables the operator to pull obliquely without causing the cup to tilt' and thereby 'reduces failure rates, reduces the incidence of scalp trauma and increases operator confidence' have been evaluated in a randomized controlled trial. 123 women with singleton pregnancies of 37 completed weeks or more, with a cephalic presentation and for whom a decision to deliver by vacuum extraction had been taken, were randomly allocated to the 'New Generation' cup or BIRD's original vacuum extractor cup; 50 mm anterior and posterior cups were used in both groups as appropriate. The two groups were comparable at entry and delivered by obstetricians of similar status. The two types of cup were similar in respect of number of failures to deliver with the vacuum extractor, correct positioning of the cup, number of pulls required for delivery and time taken to expedite delivery. Cup detachments occurred in nine cases allocated to the 'New Generation' cup compared with four allocated to the original BIRD cup. The babies in the two groups were in similar condition at birth and sustained similar amounts of scalp trauma. Neonatal jaundice, both clinical and biochemical, was more common in babies delivered with the 'New Generation cup' and this was reflected in greater use of phototherapy in this group. Operators were equally divided in their preference of cup.(ABSTRACT TRUNCATED AT 250 WORDS)
Large-scale magnetic field generation by randomly forced shearing waves.
Heinemann, T; McWilliams, J C; Schekochihin, A A
2011-12-16
A rigorous theory for the generation of a large-scale magnetic field by random nonhelically forced motions of a conducting fluid combined with a linear shear is presented in the analytically tractable limit of low magnetic Reynolds number (Rm) and weak shear. The dynamo is kinematic and due to fluctuations in the net (volume-averaged) electromotive force. This is a minimal proof-of-concept quasilinear calculation aiming to put the shear dynamo, a new effect recently found in numerical experiments, on a firm theoretical footing. Numerically observed scalings of the wave number and growth rate of the fastest-growing mode, previously not understood, are derived analytically. The simplicity of the model suggests that shear dynamo action may be a generic property of sheared magnetohydrodynamic turbulence.
Ohsawa, Yusuke; Yamaguchi, Kazuhiro; Ichikawa, Tsubasa; Sakamoto, Yuji
2013-01-01
Computer-generated holograms (CGHs) using multiview images (MVIs) are holograms generated with multiple ordinary cameras. This process typically requires a huge number of cameras arranged at high density. In this paper, we propose a method to improve CGH using MVIs that obtains the MVIs by using voxel models rather than cameras. In the proposed method the voxel model is generated using the shape-from-silhouette (SFS) technique. We perform SFS using a small number of cameras arranged sparsely to create voxel models of objects and then generate the required number of images from these models by volume rendering. This enables us to generate CGHs using MVIs with just a small number of sparsely arranged cameras. Moreover, the proposed method arrange CGHs using MVIs at arbitrary positions.
NASA Astrophysics Data System (ADS)
Inose, Yuta; Ema, Kazuhiro; Kishino, Katsumi
2017-08-01
We report the dependence of randomness in sample configuration on stimulated emission phenomena in two-dimensional nanocolumn arrays. From the wavelength selectivity of the photoluminescence, we found that the stimulated emission is apparently related to a distributed feedback mechanism. By comparing the emission behavior between two regularly arranged InGaN/GaN nanocolumn samples with different degrees of randomness, we found that localization effects become prominent if the sample array has any randomness, even in an almost perfect sample. Several modes are localized at different areas in the nanostructures and partially overlap in space, and they compete with each other, especially in a slightly imperfect sample. In addition to the randomness dependence, by observing the wave number space images of the photoluminescence, we confirmed that the stimulated emission phenomena in the crystal arrays are generated by Bragg diffraction at photonic band edges, though the modes have some degree of variability via the sample randomness.
Components of random generation by normal subjects and patients with dysexecutive syndrome.
Spatt, J; Goldenberg, G
1993-11-01
The study presents a hypothesis on how randomness could be simulated by human subjects. Three sources of deviation from randomness are predicted: (1) the preferred application of overlearned production schemata for producing sequences of digits, (2) a wrong concept of randomness, and (3) the impossibility to monitor for redundancies of higher- than those of first-order. Deviations of random generation of digits produced by healthy subjects, patients with chronic frontal lobe damage, and patients with Parkinson's disease from random sequences produced by a computer program can be explained by the differential influence of these factors. Whereas incorrect concepts of randomness and limits on monitoring capacity distinguished all sequences produced by humans from actual random sequences, persistence on a single production strategy distinguished brain-damaged patients from controls. Random generation of digits appears to be a theoretically transparent and clinically useful test of executive function.
Records for the number of distinct sites visited by a random walk on the fully connected lattice
NASA Astrophysics Data System (ADS)
Turban, Loïc
2015-11-01
We consider a random walk on the fully connected lattice with N sites and study the time evolution of the number of distinct sites s visited by the walker on a subset with n sites. A record value v is obtained for s at a record time t when the walker visits a site of the subset for the first time. The record time t is a partial covering time when v\\lt n and a total covering time when v = n. The probability distributions for the number of records s, the record value v and the record (covering) time t, involving r-Stirling numbers, are obtained using generating function techniques. The mean values, variances and skewnesses are deduced from the generating functions. In the scaling limit the probability distributions for s and v lead to the same Gaussian density. The fluctuations of the record time t are also Gaussian at partial covering, when n-v={{O}}(n). They are distributed according to the type-I Gumbel extreme-value distribution at total covering, when v = n. A discrete sequence of generalized Gumbel distributions, indexed by n-v, is obtained at almost total covering, when n-v={{O}}(1). These generalized Gumbel distributions are crossing over to the Gaussian distribution when n - v increases.
Random Variate Generation for Bayesian Nonparametric Reliability Analysis
2005-05-01
functions 21 22 U = rv.mrand(); //uniform(0,1) variate 23 N = rv.stdnorm(); //normal(0,1) variate 24 Chi = rv.ChiSquare(8); // ChiSquare n = 8 d.f. 25 Gam...and mu ≥ 0 for lognormal. To obtain a Chi Squared random variate with n degrees of freedom, call function ChiSquare (n) with integer valued n ≥ 1. For... ChiSquare (): Returns ChiSquare R.V. using stdnorm(). *************************************************************************/ double RanV:: ChiSquare
Annoni, J.; Pegna, A.
1997-01-01
OBJECTIVE—To test the hypothesis that, during random motor generation, the spatial contingencies inherent to the task would induce additional preferences in normal subjects, shifting their performances farther from randomness. By contrast, perceptual or executive dysfunction could alter these task related biases in patients with brain damage. METHODS—Two groups of patients, with right and left focal brain lesions, as well as 25 right handed subjects matched for age and handedness were asked to execute a random choice motor task—namely, to generate a random series of 180 button presses from a set of 10 keys placed vertically in front of them. RESULTS—In the control group, as in the left brain lesion group, motor generation was subject to deviations from theoretical expected randomness, similar to those when numbers are generated mentally, as immediate repetitions (successive presses on the same key) are avoided. However, the distribution of button presses was also contingent on the topographic disposition of the keys: the central keys were chosen more often than those placed at extreme positions. Small distances were favoured, particularly with the left hand. These patterns were influenced by implicit strategies and task related contingencies. By contrast, right brain lesion patients with frontal involvement tended to show a more square distribution of key presses—that is, the number of key presses tended to be more equally distributed. The strategies were also altered by brain lesions: the number of immediate repetitions was more frequent when the lesion involved the right frontal areas yielding a random generation nearer to expected theoretical randomness. The frequency of adjacent key presses was increased by right anterior and left posterior cortical as well as by right subcortical lesions, but decreased by left subcortical lesions. CONCLUSIONS—Depending on the side of the lesion and the degree of cortical-subcortical involvement, the
Copy number variation of individual cattle genomes using next-generation sequencing
USDA-ARS?s Scientific Manuscript database
Copy Number Variations (CNVs) affect a wide range of phenotypic traits; however, CNVs in or near segmental duplication regions are often difficult to track. Using a read depth approach based on next generation sequencing, we examined genome-wide copy number differences among five taurine (three Angu...
Copy number variation of individual cattle genomes using next-generation sequencing
USDA-ARS?s Scientific Manuscript database
Copy number variations (CNVs) affect a wide range of phenotypic traits; however, CNVs in or near segmental duplication regions are often intractable. Using a read depth approach based on next-generation sequencing, we examined genome-wide copy number differences among five taurine (three Angus, one ...
Individualized cattle copy number and segmental duplication maps using next generation sequencing
USDA-ARS?s Scientific Manuscript database
Copy Number Variations (CNVs) affect a wide range of phenotypic traits; however, CNVs in or near segmental duplication regions are often intractable. Using a read depth approach based on next generation sequencing, we examined genome-wide copy number differences among five taurine (three Angus, one ...
The exact distribution of the condition number of complex random matrices.
Shi, Lin; Gan, Taibin; Zhu, Hong; Gu, Xianming
2013-01-01
Let G(m×n) (m ≥ n) be a complex random matrix and W = G(m×n)(H)G(m×n) which is the complex Wishart matrix. Let λ1 > λ2 > …>λn > 0 and σ1 > σ2 > …>σn > 0 denote the eigenvalues of the W and singular values of G(m×n), respectively. The 2-norm condition number of G(m×n) is k2(G(m×n)) = √(λ1/λn) =σ1/σn. In this paper, the exact distribution of the condition number of the complex Wishart matrices is derived. The distribution is expressed in terms of complex zonal polynomials.
Kouritzin, Michael A; Newton, Fraser; Wu, Biao
2013-04-01
Herein, we propose generating CAPTCHAs through random field simulation and give a novel, effective and efficient algorithm to do so. Indeed, we demonstrate that sufficient information about word tests for easy human recognition is contained in the site marginal probabilities and the site-to-nearby-site covariances and that these quantities can be embedded directly into certain conditional probabilities, designed for effective simulation. The CAPTCHAs are then partial random realizations of the random CAPTCHA word. We start with an initial random field (e.g., randomly scattered letter pieces) and use Gibbs resampling to re-simulate portions of the field repeatedly using these conditional probabilities until the word becomes human-readable. The residual randomness from the initial random field together with the random implementation of the CAPTCHA word provide significant resistance to attack. This results in a CAPTCHA, which is unrecognizable to modern optical character recognition but is recognized about 95% of the time in a human readability study.
Deke, John
2016-10-25
Cluster randomized controlled trials (CRCTs) often require a large number of clusters in order to detect small effects with high probability. However, there are contexts where it may be possible to design a CRCT with a much smaller number of clusters (10 or fewer) and still detect meaningful effects. The objective is to offer recommendations for best practices in design and analysis for small CRCTs. I use simulations to examine alternative design and analysis approaches. Specifically, I examine (1) which analytic approaches control Type I errors at the desired rate, (2) which design and analytic approaches yield the most power, (3) what is the design effect of spurious correlations, and (4) examples of specific scenarios under which impacts of different sizes can be detected with high probability. I find that (1) mixed effects modeling and using Ordinary Least Squares (OLS) on data aggregated to the cluster level both control the Type I error rate, (2) randomization within blocks is always recommended, but how best to account for blocking through covariate adjustment depends on whether the precision gains offset the degrees of freedom loss, (3) power calculations can be accurate when design effects from small sample, spurious correlations are taken into account, and (4) it is very difficult to detect small effects with just four clusters, but with six or more clusters, there are realistic circumstances under which small effects can be detected with high probability. © The Author(s) 2016.
[Cell membrane electroporator with digital generation of random shaped pulses].
Iakovenko, S A; Trubitsin, B V
2003-01-01
A Digital Poration System (DPS), a versatile device for electrotreatment of biological objects by electric field pulses; was designed, constructed, and implemented. A feature distinguishing DPS from the currently available electroporators based on capacitor discharge through the load is the use of a digital-to-analog converter card as a generator of pulses applied for electroporation of biological membranes, with further amplification of the pulse by both voltage and current. The shape of pulses, including bipolar pulses, is arbitrarily programmable in DPS unlike other electroporators providing exponentially decaying and square-wave pulses only. Thus, the application area of DPS is substantially extended. In DPS, many of the drawbacks inherent in capacitor electroporators are removed, including the need for an additional external pulse analyzer monitoring and logging the electroporation processes, the necessity to recharge the capacitor before any new pulse, a poor precision of setting and measuring the pulse parameters, the need for an additional generator of long-lasting low-voltage signals for electrophoresis of ions into the porated object, the need for additional AC generators for the alignment of cells before, after, and during electroporation, and the need for an additional microprocessor to control multi-pulse and/or repetitive protocols. DPS provides a slew rate of about 1 V/1 ns required for the electroporation of most mammalian somatic cells, with +/- 250 V output voltage and 500 Ohm load resistance. The application area of DPS is much wider than for the available porators. It includes electrochemotherapy, cell electrofusion, oocyte activation by mimicking calcium waves (the latter two are the crucial components of mammalian organism cloning technology), dielectrophoretic bunching and orientation ordering of cells, sorting of cells, and electrophoresis of charged species into the cells.
Geometric random walk of finite number of agents under constant variance
NASA Astrophysics Data System (ADS)
Yano, Ryosuke
2017-05-01
The characteristics of the 1D geometric random walk of a finite number of agents are investigated by assuming constant variance. Firstly, the characteristics of the steady state solution of the distribution function, which is obtained using the extended geometric Brownian motion (EGBM), are investigated in the framework of the 1D Fokker-Planck type equation. The uniqueness and existence of the steady state solution of the distribution function requires the number of particles to be finite. To avoid the divergence of the steady state solution of the distribution function at the mean value in the 1D Fokker-Planck type equation, the hybrid model, which is a combination of EGBM and normal BM, is proposed. Next, the steady state solution of the distribution function, which is obtained using the geometric Lévy flight, is investigated under constant variance in the framework of the space fractional 1D Fokker-Planck type equation. Additionally, we confirm that the solution of the distribution function obtained using the super-elastic and inelastic (SI-) Boltzmann equation under constant variance approaches the Cauchy distribution, when the power law number of the relative velocity increases. Finally, dissipation processes of the pressure deviator and heat flux are numerically investigated using the 2D space fractional Fokker-Planck type equations for Lévy flight and SI-Boltzmann equation by assuming their linear response relations.
On statistical inference for the random set generated Cox process with set-marking.
Penttinen, Antti; Niemi, Aki
2007-04-01
Cox point process is a process class for hierarchical modelling of systems of non-interacting points in Rd under environmental heterogeneity which is modelled through a random intensity function. In this work a class of Cox processes is suggested where the random intensity is generated by a random closed set. Such heterogeneity appears for example in forestry where silvicultural treatments like harvesting and site-preparation create geometrical patterns for tree density variation in two different phases. In this paper the second order property, important both in data analysis and in the context of spatial sampling, is derived. The usefulness of the random set generated Cox process is highly increased, if for each point it is observed whether it is included in the random set or not. This additional information is easy and economical to obtain in many cases and is hence of practical value; it leads to marks for the points. The resulting random set marked Cox process is a marked point process where the marks are intensity-dependent. The problem with set-marking is that the marks are not a representative sample from the random set. This paper derives the second order property of the random set marked Cox process and suggests a practical estimation method for area fraction and covariance of the random set and for the point densities within and outside the random set. A simulated example and a forestry example are given.
NASA Astrophysics Data System (ADS)
Marino, Ricardo; Majumdar, Satya N.; Schehr, Grégory; Vivo, Pierpaolo
2016-09-01
Let Pβ(V )(NI) be the probability that a N ×N β -ensemble of random matrices with confining potential V (x ) has NI eigenvalues inside an interval I =[a ,b ] on the real line. We introduce a general formalism, based on the Coulomb gas technique and the resolvent method, to compute analytically Pβ(V )(NI) for large N . We show that this probability scales for large N as Pβ(V )(NI) ≈exp[-β N2ψ(V )(NI/N ) ] , where β is the Dyson index of the ensemble. The rate function ψ(V )(kI) , independent of β , is computed in terms of single integrals that can be easily evaluated numerically. The general formalism is then applied to the classical β -Gaussian (I =[-L ,L ] ), β -Wishart (I =[1 ,L ] ), and β -Cauchy (I =[-L ,L ] ) ensembles. Expanding the rate function around its minimum, we find that generically the number variance v a r (NI) exhibits a nonmonotonic behavior as a function of the size of the interval, with a maximum that can be precisely characterized. These analytical results, corroborated by numerical simulations, provide the full counting statistics of many systems where random matrix models apply. In particular, we present results for the full counting statistics of zero-temperature one-dimensional spinless fermions in a harmonic trap.
Field Line Random Walk in Isotropic Magnetic Turbulence up to Infinite Kubo Number
NASA Astrophysics Data System (ADS)
Sonsrettee, W.; Wongpan, P.; Ruffolo, D. J.; Matthaeus, W. H.; Chuychai, P.; Rowlands, G.
2013-12-01
In astrophysical plasmas, the magnetic field line random walk (FLRW) plays a key role in the transport of energetic particles. In the present, we consider isotropic magnetic turbulence, which is a reasonable model for interstellar space. Theoretical conceptions of the FLRW have been strongly influenced by studies of the limit of weak fluctuations (or a strong mean field) (e.g, Isichenko 1991a, b). In this case, the behavior of FLRW can be characterized by the Kubo number R = (b/B0)(l_∥ /l_ \\bot ) , where l∥ and l_ \\bot are turbulence coherence scales parallel and perpendicular to the mean field, respectively, and b is the root mean squared fluctuation field. In the 2D limit (R ≫ 1), there has been an apparent conflict between concepts of Bohm diffusion, which is based on the Corrsin's independence hypothesis, and percolative diffusion. Here we have used three non-perturbative analytic techniques based on Corrsin's independence hypothesis for B0 = 0 (R = ∞ ): diffusive decorrelation (DD), random ballistic decorrelation (RBD) and a general ordinary differential equation (ODE), and compared them with direct computer simulations. All the analytical models and computer simulations agree that isotropic turbulence for R = ∞ has a field line diffusion coefficient that is consistent with Bohm diffusion. Partially supported by the Thailand Research Fund, NASA, and NSF.
Stelfox, Henry Thomas; Goverman, Jeremy
2008-12-01
Injuries represent an important and growing global burden of disease. The availability of evidence-based injury control interventions is unknown. We aimed to assess trends with respect to the number, content, and methodologic quality of reports of randomized controlled trials (RCTs) in the prevention and care of injuries. We searched MEDLINE and the Cochrane Central Register of Controlled Trials for reports of RCTs of interventions in the prevention and care of injuries published between January 1, 1966 and January 1, 2006. Ten percent of reports, stratified by year, were randomly sampled. Studies were abstracted using a standardized form for nature of intervention, sample size, patients studied, and methodologic quality. The rate of publication of injury-related RCTs increased from 1.2 to 5.3 articles per 100 RCTs published in MEDLINE (p < 0.001) during the study period. A total of 308 reports were included in the analysis of content and methodologic quality. Poisonings (31 [10%]) were the single most common isolated mechanism of patient injury studied, whereas only 12 reports (4%) focused on road traffic injuries. The majority of interventions were hospital based (211 [68%]) and half (45%) were judged to be only available in high-income countries. Allocation concealment was deemed adequate in 73 articles (24%). One quarter of reports documented blinding of participants (77 [25%]), investigators (68 [22%]), and outcome assessors (83 [27%]). Only 44 articles (14%) reported intention-to-treat analyses. The number of RCTs specific to the prevention and care of injuries is small, but increasing. The reporting of injury-related RCTs has important deficiencies including inadequate allocation concealment; failure to blind patients, investigators, and assessors; and per protocol analyses. In addition, many interventions studied are not available in low-income countries where the majority of the world's population resides and injury rates are highest.
NASA Astrophysics Data System (ADS)
Liu, Yuexin; Metzner, John J.; Guo, Ruyan; Yu, Francis T. S.
2005-09-01
An efficient and secure algorithm for random phase mask generation used in optical data encryption and transmission system is proposed, based on Diffie-Hellman public key distribution. Thus-generated random mask has higher security due to the fact that it is never exposed to the vulnerable transmitting channels. The effectiveness to retrieve the original image and its robustness against blind manipulation have been demonstrated by our numerical results. In addition, this algorithm can be easily extended to multicast networking system and refresh of this shared random key is also very simple to implement.
Generation of photon-number squeezed states with a fiber-optic symmetric interferometer.
Hosaka, Aruto; Hirosawa, Kenichi; Sawada, Ryota; Kannari, Fumihiko
2015-07-27
We numerically and experimentally demonstrate photon-number squeezed state generation with a symmetric fiber interferometer in an 800-nm wavelength and compared with an asymmetric fiber interferometer, although photon-number squeezed pulses have been generated only with asymmetric interferometers. Even though we obtain -1.0dB squeezing with an asymmetric fiber interferometer, since perfect spectral phase and intensity matching between displacement and signal pulses are achieved with a symmetric fiber interferometer, we obtain better squeezing of -3.1dB. We also numerically calculate and clarify this scheme's usefulness at a 1.55-μm wavelength.
On an acoustic field generated by subsonic jet at low Reynolds numbers
NASA Technical Reports Server (NTRS)
Yamamoto, K.; Arndt, R. E. A.
1978-01-01
An acoustic field generated by subsonic jets at low Reynolds numbers was investigated. This work is motivated by the need to increase the fundamental understanding of the jet noise generation mechanism which is essential to the development of further advanced techniques of noise suppression. The scope of this study consists of two major investigation. One is a study of large scale coherent structure in the jet turbulence, and the other is a study of the Reynolds number dependence of jet noise. With this in mind, extensive flow and acoustic measurements in low Reynolds number turbulent jets (8,930 less than or equal to M less than or equal to 220,000) were undertaken using miniature nozzles of the same configuration but different diameters at various exist Mach numbers (0.2 less than or equal to M less than or equal to 0.9).
Image encryption using the Gyrator transform and random phase masks generated by using chaos
NASA Astrophysics Data System (ADS)
Vilardy, Juan M.; Jimenez, Carlos J.; Perez, Ronal
2017-06-01
The Gyrator transform (GT), chaotic random phase masks (CRPMs) and a random permutation of the Jigsaw transform (JT) are utilized to design an images encryption-decryption system. The encryption-decryption system is based on the double random phase encoding (DRPE) in the Gyrator domain (GD), this technique uses two random phase masks (RPMs) to encode the image to encrypt (original image) into a random noise. The RPMs are generated by using chaos, these masks are CRPMs. The parameters of the chaotic function have the control of the generation of the CRPMs. We apply a random permutation to the resulting image of the DRPE technique, with the purpose of obtaining an encrypted image with a higher randomness. In order to successfully retrieve the original image (without errors or noise-free) at the output of the decryption system is necessary to have all the proper keys, which are: the rotation angles of the GTs, the parameters of the chaotic function utilized to generate the two CRPMs and the random permutation of the JT. We check and analyze the validity of the image encryption and decryption systems by means of computing simulations.
Generation of Multi-Lod 3d City Models in Citygml with the Procedural Modelling Engine RANDOM3DCITY
NASA Astrophysics Data System (ADS)
Biljecki, F.; Ledoux, H.; Stoter, J.
2016-09-01
The production and dissemination of semantic 3D city models is rapidly increasing benefiting a growing number of use cases. However, their availability in multiple LODs and in the CityGML format is still problematic in practice. This hinders applications and experiments where multi-LOD datasets are required as input, for instance, to determine the performance of different LODs in a spatial analysis. An alternative approach to obtain 3D city models is to generate them with procedural modelling, which is - as we discuss in this paper - well suited as a method to source multi-LOD datasets useful for a number of applications. However, procedural modelling has not yet been employed for this purpose. Therefore, we have developed RANDOM3DCITY, an experimental procedural modelling engine for generating synthetic datasets of buildings and other urban features. The engine is designed to produce models in CityGML and does so in multiple LODs. Besides the generation of multiple geometric LODs, we implement the realisation of multiple levels of spatiosemantic coherence, geometric reference variants, and indoor representations. As a result of their permutations, each building can be generated in 392 different CityGML representations, an unprecedented number of modelling variants of the same feature. The datasets produced by RANDOM3DCITY are suited for several applications, as we show in this paper with documented uses. The developed engine is available under an open-source licence at Github at Random3Dcity"target="_blank">http://github.com/tudelft3d/Random3Dcity.
NASA Astrophysics Data System (ADS)
Beale, Paul
2015-03-01
We propose a new class of pseudorandom number generators based on Pohlig-Hellman exponentiation ciphers. The method generates uniform pseudorandom streams by encrypting simple sequences of short integer messages into ciphertexts by exponentiation modulo prime numbers. The advantages of the method are: the method is trivially parallelizable by parameterization with each pseudorandom number generator derived from an independent prime modulus, the method is fully scalable on massively parallel computing clusters due to the large number of primes available for each implementation, the seeding and initialization of the independent streams is simple, the method requires only a few integer multiply-mod operations per pseudorandom number, the state of each instance is defined by only a few integer values, the period of each instance is different, and the method passes a battery of intrastream and interstream correlation tests using up to 1013 pseudorandom numbers per test. We propose an implementation using 32-bit prime moduli with small exponents that require only a few 64-bit multiply-mod operations that can be executed directly in hardware. The 32-bit implementation we propose has millions of possible instances, all with periods greater than 1018. Supported by NSF CNS-082179.
Miller, Paul
2013-01-01
Randomly connected recurrent networks of excitatory groups of neurons can possess a multitude of attractor states. When the internal excitatory synapses of these networks are depressing, the attractor states can be destabilized with increasing input. This leads to an itinerancy, where with either repeated transient stimuli, or increasing duration of a single stimulus, the network activity advances through sequences of attractor states. We find that the resulting network state, which persists beyond stimulus offset, can encode the number of stimuli presented via a distributed representation of neural activity with non-monotonic tuning curves for most neurons. Increased duration of a single stimulus is encoded via different distributed representations, so unlike an integrator, the network distinguishes separate successive presentations of a short stimulus from a single presentation of a longer stimulus with equal total duration. Moreover, different amplitudes of stimulus cause new, distinct activity patterns, such that changes in stimulus number, duration and amplitude can be distinguished from each other. These properties of the network depend on dynamic depressing synapses, as they disappear if synapses are static. Thus, short-term synaptic depression allows a network to store separately the different dynamic properties of a spatially constant stimulus.
Paez, T.L.; Gregory, D.L.
1990-01-01
This paper and a companion paper show that the traditional limits on amplitude and frequency that can be generated in a laboratory test on a vibration exciter can be substantially extended. This is accomplished by attaching a device to the shaker that permits controlled metal to metal impacts that generate a high acceleration, high frequency environment on a test surface. A companion paper derives some of the mechanical relations for the system. This paper shows that a sinusoidal shaker input can be used to excite deterministic chaotic dynamics of the system yielding a random vibration environment on the test surface, or a random motion of the shaker can be used to generate a random vibration environment on the test surface. Numerical examples are presented to show the kind of environments that can be generated in this system. 9 refs., 9 figs.
USDA-ARS?s Scientific Manuscript database
Many species in temperate climates show latitudinal variation in life-cycle corresponding to synchronization with seasonal fluctuations in resources. In particular, insects often vary clinally in voltinism (the number of generations per year) which is determined by the timing of diapause terminatio...
NASA Astrophysics Data System (ADS)
Liu, Tongjun; Wang, Tongcai; Luan, Weiling; Cao, Qimin
2017-01-01
Waste heat recovery through thermoelectric generators is a promising way to improve energy conversion efficiency. This paper proposes a type of heat pipe assisted thermoelectric generator (HP-TEG) system. The expandable evaporator and condenser surface of the heat pipe facilitates the intensive assembly of thermoelectric (TE) modules to compose a compact device. Compared with a conventional layer structure thermoelectric generator, this system is feasible for the installment of more TE couples, thus increasing power output. To investigate the performance of the HP-TEG and the optimal number of TE couples, a theoretical model was presented and verified by experiment results. Further theoretical analysis results showed the performance of the HP-TEG could be further improved by optimizing the parameters, including the inlet air temperature, the thermal resistance of the heating section, and thermal resistance of the cooling structure. Moreover, applying a proper number of TE couples is important to acquire the best power output performance.
Fractal generator for efficient production of random planar patterns and symbols in digital mapping
NASA Astrophysics Data System (ADS)
Chen, Qiyu; Liu, Gang; Ma, Xiaogang; Li, Xinchuan; He, Zhenwen
2017-08-01
In digital cartography, the automatic generation of random planar patterns and symbols is still an ongoing challenge. Those patterns and symbols of randomness have randomly variated configurations and boundaries, and their generating algorithms are constrained by the shape features, cartographic standards and many other conditions. The fractal geometry offers favorable solutions to simulate random boundaries and patterns. In the work presented in this paper, we used both fractal theory and random Iterated Function Systems (IFS) to develop a method for the automatic generation of random planar patterns and symbols. The marshland and the trough cross-bedding patterns were used as two case studies for the implementation of the method. We first analyzed the morphological characteristics of those two planar patterns. Then we designed algorithms and implementation schemes addressing the features of each pattern. Finally, we ran the algorithms to generate the patterns and symbols, and compared them with the requirements of a few digital cartographic standards. The method presented in this paper has already been deployed in a digital mapping system for practical uses. The flexibility of the method also allows it to be reused and/or adapted in various software platforms for digital mapping.
Selak, Vanessa; Crengle, Sue; Elley, C Raina; Wadham, Angela; Harwood, Matire; Rafter, Natasha; Bullen, Chris; Pillai, Avinesh; Arroll, Bruce; Rodgers, Anthony
2013-06-22
ori were more likely than non-Māori to proceed to subsequent stages of recruitment. Differences between randomized Māori and non-Māori were evident (e.g. Maori were less likely to have established coronary artery disease). Recruitment of equal numbers of indigenous and non-indigenous participants is possible if it is prioritised, adequately resourced and self-determination is supported. The trial is registered with the Australian New Zealand Clinical Trial Registry ACTRN12606000067572.
Early stage hot spot analysis through standard cell base random pattern generation
NASA Astrophysics Data System (ADS)
Jeon, Joong-Won; Song, Jaewan; Kim, Jeong-Lim; Park, Seongyul; Yang, Seung-Hune; Lee, Sooryong; Kang, Hokyu; Madkour, Kareem; ElManhawy, Wael; Lee, SeungJo; Kwan, Joe
2017-04-01
Due to limited availability of DRC clean patterns during the process and RET recipe development, OPC recipes are not tested with high pattern coverage. Various kinds of pattern can help OPC engineer to detect sensitive patterns to lithographic effects. Random pattern generation is needed to secure robust OPC recipe. However, simple random patterns without considering real product layout style can't cover patterning hotspot in production levels. It is not effective to use them for OPC optimization thus it is important to generate random patterns similar to real product patterns. This paper presents a strategy for generating random patterns based on design architecture information and preventing hotspot in early process development stage through a tool called Layout Schema Generator (LSG). Using LSG, we generate standard cell based on random patterns reflecting real design cell structure - fin pitch, gate pitch and cell height. The output standard cells from LSG are applied to an analysis methodology to assess their hotspot severity by assigning a score according to their optical image parameters - NILS, MEEF, %PV band and thus potential hotspots can be defined by determining their ranking. This flow is demonstrated on Samsung 7nm technology optimizing OPC recipe and early enough in the process avoiding using problematic patterns.
Allele-specific copy number profiling by next-generation DNA sequencing.
Chen, Hao; Bell, John M; Zavala, Nicolas A; Ji, Hanlee P; Zhang, Nancy R
2015-02-27
The progression and clonal development of tumors often involve amplifications and deletions of genomic DNA. Estimation of allele-specific copy number, which quantifies the number of copies of each allele at each variant loci rather than the total number of chromosome copies, is an important step in the characterization of tumor genomes and the inference of their clonal history. We describe a new method, falcon, for finding somatic allele-specific copy number changes by next generation sequencing of tumors with matched normals. falcon is based on a change-point model on a bivariate mixed Binomial process, which explicitly models the copy numbers of the two chromosome haplotypes and corrects for local allele-specific coverage biases. By using the Binomial distribution rather than a normal approximation, falcon more effectively pools evidence from sites with low coverage. A modified Bayesian information criterion is used to guide model selection for determining the number of copy number events. Falcon is evaluated on in silico spike-in data and applied to the analysis of a pre-malignant colon tumor sample and late-stage colorectal adenocarcinoma from the same individual. The allele-specific copy number estimates obtained by falcon allows us to draw detailed conclusions regarding the clonal history of the individual's colon cancer.
Fuchs, Lynn S.; Powell, Sarah R.; Seethaler, Pamela M.; Cirino, Paul T.; Fletcher, Jack M.; Fuchs, Douglas; Hamlett, Carol L.; Zumeta, Rebecca O.
2009-01-01
The purposes of this study were to assess the efficacy of remedial tutoring for 3rd graders with mathematics difficulty, to investigate whether tutoring is differentially efficacious depending on students’ math difficulty status (mathematics difficulty alone vs. mathematics plus reading difficulty), to explore transfer from number combination (NC) remediation, and to examine the transportability of the tutoring protocols. At 2 sites, 133 students were stratified on mathematics difficulty status and site and then randomly assigned to 3 conditions: control (no tutoring), tutoring on automatic retrieval of NCs (i.e., Math Flash), or tutoring on word problems with attention to the foundational skills of NCs, procedural calculations, and algebra (i.e., Pirate Math). Tutoring occurred for 16 weeks, 3 sessions per week and 20–30 min per session. Math Flash enhanced fluency with NCs with transfer to procedural computation but without transfer to algebra or word problems. Pirate Math enhanced word problem skill as well as fluency with NCs, procedural computation, and algebra. Tutoring was not differentially efficacious as a function of students’ mathematics difficulty status. The tutoring protocols proved transportable across sites. PMID:19865600
Method for Generating a Randomized Flight-by-Flight Loading Sequence for an Aircraft
1980-07-01
candidates p in the random sampling process Mabc The number of different stresses in the negative gFn flight stress spectrum for the ath control point of... Mabc The number of different stresses in the one g flight Fg 9stress spectrum for the ath control point of an air- craft flying the cth mission...4 abm A simple graph derived from nabm whose ordinates "L~n LT n T are the selection candidates in the random samplingprocess Mabc The number of
Theory of fast nondeterministic physical random-bit generation with chaotic lasers.
Harayama, Takahisa; Sunada, Satoshi; Yoshimura, Kazuyuki; Muramatsu, Jun; Arai, Ken-ichi; Uchida, Atsushi; Davis, Peter
2012-04-01
We theoretically show that completely stochastic fast physical random bit generation at a rate of more than one gigabit per second can be realized by using lasers with optical delayed feedback which creates high-dimensional chaos of laser light outputs. The theory is based on the mixing property of chaos, which transduces microscopic quantum noise of spontaneous emission in lasers into random transitions between discrete macroscopic states.
ERIC Educational Resources Information Center
Gersten, Russell; Rolfhus, Eric; Clarke, Ben; Decker, Lauren E.; Wilkins, Chuck; Dimino, Joseph
2015-01-01
Replication studies are extremely rare in education. This randomized controlled trial (RCT) is a scale-up replication of Fuchs et al., which in a sample of 139 found a statistically significant positive impact for Number Rockets, a small-group intervention for at-risk first graders that focused on building understanding of number operations. The…
ERIC Educational Resources Information Center
Gersten, Russell; Rolfhus, Eric; Clarke, Ben; Decker, Lauren E.; Wilkins, Chuck; Dimino, Joseph
2015-01-01
Replication studies are extremely rare in education. This randomized controlled trial (RCT) is a scale-up replication of Fuchs et al., which in a sample of 139 found a statistically significant positive impact for Number Rockets, a small-group intervention for at-risk first graders that focused on building understanding of number operations. The…
Code to generate random identifiers and select QA/QC samples
Mehnert, Edward
1992-01-01
SAMPLID is a PC-based, FORTRAN-77 code which generates unique numbers for identification of samples, selection of QA/QC samples, and generation of labels. These procedures are tedious, but using a computer code such as SAMPLID can increase efficiency and reduce or eliminate errors and bias. The algorithm, used in SAMPLID, for generation of pseudorandom numbers is free of statistical flaws present in commonly available algorithms.
Graphene based widely-tunable and singly-polarized pulse generation with random fiber lasers
Yao, B. C.; Rao, Y. J.; Wang, Z. N.; Wu, Y.; Zhou, J. H.; Wu, H.; Fan, M. Q.; Cao, X. L.; Zhang, W. L.; Chen, Y. F.; Li, Y. R.; Churkin, D.; Turitsyn, S.; Wong, C. W.
2015-01-01
Pulse generation often requires a stabilized cavity and its corresponding mode structure for initial phase-locking. Contrastingly, modeless cavity-free random lasers provide new possibilities for high quantum efficiency lasing that could potentially be widely tunable spectrally and temporally. Pulse generation in random lasers, however, has remained elusive since the discovery of modeless gain lasing. Here we report coherent pulse generation with modeless random lasers based on the unique polarization selectivity and broadband saturable absorption of monolayer graphene. Simultaneous temporal compression of cavity-free pulses are observed with such a polarization modulation, along with a broadly-tunable pulsewidth across two orders of magnitude down to 900 ps, a broadly-tunable repetition rate across three orders of magnitude up to 3 MHz, and a singly-polarized pulse train at 41 dB extinction ratio, about an order of magnitude larger than conventional pulsed fiber lasers. Moreover, our graphene-based pulse formation also demonstrates robust pulse-to-pulse stability and wide-wavelength operation due to the cavity-less feature. Such a graphene-based architecture not only provides a tunable pulsed random laser for fiber-optic sensing, speckle-free imaging, and laser-material processing, but also a new way for the non-random CW fiber lasers to generate widely tunable and singly-polarized pulses. PMID:26687730
Photon-number entangled states generated in Kerr media with optical parametric pumping
Kowalewska-Kudlaszyk, A.; Leonski, W.; Perina, Jan Jr.
2011-05-15
Two nonlinear Kerr oscillators mutually coupled by parametric pumping are studied as a source of states entangled in photon numbers. Temporal evolution of entanglement quantified by negativity shows the effects of sudden death and birth of entanglement. Entanglement is preserved even in asymptotic states under certain conditions. The role of reservoirs at finite temperature in entanglement evolution is elucidated. Relation between generation of entangled states and violation of Cauchy-Schwartz inequality for oscillator intensities is found.
Generation of a superposition of odd photon number states for quantum information networks.
Neergaard-Nielsen, J S; Nielsen, B Melholt; Hettich, C; Mølmer, K; Polzik, E S
2006-08-25
We report on the experimental observation of quantum-network-compatible light described by a nonpositive Wigner function. The state is generated by photon subtraction from a squeezed vacuum state produced by a continuous wave optical parametric amplifier. Ideally, the state is a coherent superposition of odd photon number states, closely resembling a superposition of weak coherent states |alpha > - |-alpha >. In the limit of low squeezing the state is basically a single photon state. Light is generated with about 10,000 and more events per second in a nearly perfect spatial mode with a Fourier-limited frequency bandwidth which matches well atomic quantum memory requirements. The generated state of light is an excellent input state for testing quantum memories, quantum repeaters, and linear optics quantum computers.
NASA Astrophysics Data System (ADS)
Saichev, A.; Helmstetter, A.; Sornette, D.
2005-06-01
We consider a general stochastic branching process,which is relevant to earthquakes as well as to many other systems, and we study the distributions of the total number of offsprings (direct and indirect aftershocks in seismicity) and of the total number of generations before extinction. We apply our results to a branching model of triggered seismicity, the ETAS (epidemic-type aftershock sequence) model. The ETAS model assumes that each earthquake can trigger other earthquakes (“aftershocks”). An aftershock sequence results in this model from the cascade of aftershocks of each past earthquake. Due to the large fluctuations of the number of aftershocks triggered directly by any earthquake (“fertility”), there is a large variability of the total number of aftershocks from one sequence to another, for the same mainshock magnitude. We study the regime in which the distribution of fertilities μ is characterized by a power law ~1/μ1+γ. For earthquakes we expect such a power-distribution of fertilities with γ=b/α based on the Gutenberg-Richter magnitude distribution ~ 10-bm and on the increase ~ 10-αm of the number of aftershocks with the mainshock magnitude m. We derive the asymptotic distributions pr(r) and pg(g) of the total number r of offsprings and of the total number g of generations until extinction following a mainshock. In the regime γ < 2 for which the distribution of fertilities has an infinite variance, we find This should be compared with the distributions obtained for standard branching processes with finite variance. These predictions are checked by numerical simulations. Our results apply directly to the ETAS model whose preferred values α=0.8 1 and b=1 puts it in the regime where the distribution of fertilities has an infinite variance. More generally, our results apply to any stochastic branching process with a power-law distribution of offsprings per mother
Use of chaotic and random vibrations to generate high frequency test inputs
Gregory, D. L.; Paez, T. L.
1990-01-01
This paper and a companion paper show the traditional limits on amplitude and frequency that can be generated in a laboratory test on a vibration exciter can be substantially extended. This is accomplished by attaching a device to the shaker that permits controlled metal to metal impacts that generate high frequency, high acceleration environment on a test surface. A companion paper (Reference 1) shows that a sinusoidal or random shaker input can be used to generate a random vibration environment on the test surface. This paper derives the three response components that occur on the test surface due to an impact on the bottom surface and the base driven response from the shaker input. These response components are used to generate impulse response functions and frequency response functions which are used in the companion paper to derive power spectral density functions for the overall response. 9 refs., 8 figs.
Sugavanam, S; Yan, Z; Kamynin, V; Kurkov, A S; Zhang, L; Churkin, D V
2014-02-10
Multiwavelength lasing in the random distributed feedback fiber laser is demonstrated by employing an all fiber Lyot filter. Stable multiwavelength generation is obtained, with each line exhibiting sub-nanometer line-widths. A flat power distribution over multiple lines is obtained, which indicates that the power between lines is redistributed in nonlinear mixing processes. The multiwavelength generation is observed both in first and second Stokes waves.
NASA Astrophysics Data System (ADS)
Meshram, S. Gajbhiye; Sharma, S. K.; Tignath, S.
2017-07-01
Watershed is an ideal unit for planning and management of land and water resources (Gajbhiye et al., IEEE international conference on advances in technology and engineering (ICATE), Bombay, vol 1, issue 9, pp 23-25, 2013a; Gajbhiye et al., Appl Water Sci 4(1):51-61, 2014a; Gajbhiye et al., J Geol Soc India (SCI-IF 0.596) 84(2):192-196, 2014b). This study aims to generate the curve number, using remote sensing and geographical information system (GIS) and the effect of slope on curve number values. The study was carried out in Kanhaiya Nala watershed located in Satna district of Madhya Pradesh. Soil map, Land Use/Land cover and slope map were generated in GIS Environment. The CN parameter values corresponding to various soil, land cover, and land management conditions were selected from Natural Resource Conservation Service (NRCS) standard table. Curve number (CN) is an index developed by the NRCS, to represent the potential for storm water runoff within a drainage area. The CN for a drainage basin is estimated using a combination of land use, soil, and antecedent soil moisture condition (AMC). In present study effect of slope on CN values were determined. The result showed that the CN unadjusted value are higher in comparison to CN adjusted with slope. Remote sensing and GIS is very reliable technique for the preparation of most of the input data required by the SCS curve number model.
NASA Astrophysics Data System (ADS)
Krieg, Mike; Thomas, Tyler; Mohseni, Kamran
2009-11-01
Both jellyfish and Squid propel themselves by ejecting high momentum vortex rings. A set of vortex ring generating thrusters were developed and tested for application in underwater vehicle propulsion. Vortex rings generated from a steady piston cylinder mechanism have a universal formation time, known as the formation number (Gharib et al. 1998), associated with reaching maximum circulation, where the vortex ring separates from its trailing shear flow. The non-dimensional jet formation time (also called the stroke ratio) plays a key role in the thrust output of the device; since thrusters operating above the formation number re-ingest the trailing jet. A variable diameter exit nozzle was used to increase the formation number of the jet to maximize thrust (which is a technique observed in squid and jellyfish locomotion). Visualization studies confirmed the ability to delay the onset of ring ``pinch-off'', using a variable nozzle, and the thrust was empirically shown to achieve a higher maximum. Additionally, a fluid slug model which was developed to predict the thrust output was adapted to incorporate a changing nozzle diameter. This model was verified with the empirical thrust data and was again shown to be accurate for stroke ratios below the formation number.
Yang, Xiuping Min, Lequan Wang, Xue
2015-05-15
This paper sets up a chaos criterion theorem on a kind of cubic polynomial discrete maps. Using this theorem, Zhou-Song's chaos criterion theorem on quadratic polynomial discrete maps and generalized synchronization (GS) theorem construct an eight-dimensional chaotic GS system. Numerical simulations have been carried out to verify the effectiveness of theoretical results. The chaotic GS system is used to design a chaos-based pseudorandom number generator (CPRNG). Using FIPS 140-2 test suit/Generalized FIPS 140-2, test suit tests the randomness of two 1000 key streams consisting of 20 000 bits generated by the CPRNG, respectively. The results show that there are 99.9%/98.5% key streams to have passed the FIPS 140-2 test suit/Generalized FIPS 140-2 test. Numerical simulations show that the different keystreams have an average 50.001% same codes. The key space of the CPRNG is larger than 2{sup 1345}. As an application of the CPRNG, this study gives an image encryption example. Experimental results show that the linear coefficients between the plaintext and the ciphertext and the decrypted ciphertexts via the 100 key streams with perturbed keys are less than 0.00428. The result suggests that the decrypted texts via the keystreams generated via perturbed keys of the CPRNG are almost completely independent on the original image text, and brute attacks are needed to break the cryptographic system.
Towse, John Nicholas; Towse, Andrea Sarah; Saito, Satoru; Maehara, Yukio; Miyake, Akira
2016-01-01
Generating random number sequences is a popular psychological task often used to measure executive functioning. We explore random generation under “joint cognition” instructions; pairs of participants take turns to compile a shared response sequence. Across three studies, we point to six key findings from this novel format. First, there are both costs and benefits from group performance. Second, repetition avoidance occurs in dyadic as well as individual production settings. Third, individuals modify their choices in a dyadic situation such that the pair becomes the unit of psychological function. Fourth, there is immediate contagion of sequence stereotypy amongst the pairs (i.e., each contributor “owns” their partner’s response). Fifth, dyad effects occur even when participants know their partner is not interacting with them (Experiment 2). Sixth, ironically, directing participants’ efforts away from their shared task responsibility can actually benefit conjoint performance (Experiment 3). These results both constrain models of random generation and illuminate processes of joint cognition. PMID:26977923
NASA Astrophysics Data System (ADS)
Yousefjani, Rozhin; Nichols, Rosanna; Salimi, Shahriar; Adesso, Gerardo
2017-06-01
Quantum metrology aims to exploit quantum phenomena to overcome classical limitations in the estimation of relevant parameters. We consider a probe undergoing a phase shift φ whose generator is randomly sampled according to a distribution with unknown concentration κ , which introduces a physical source of noise. We then investigate strategies for the joint estimation of the two parameters φ and κ given a finite number N of interactions with the phase imprinting channel. We consider both single qubit and multipartite entangled probes, and identify regions of the parameters where simultaneous estimation is advantageous, resulting in up to a twofold reduction in resources. Quantum enhanced precision is achievable at moderate N , while for sufficiently large N classical strategies take over and the precision follows the standard quantum limit. We show that full-scale entanglement is not needed to reach such an enhancement, as efficient strategies using significantly fewer qubits in a scheme interpolating between the conventional sequential and parallel metrological schemes yield the same effective performance. These results may have relevant applications in optimization of sensing technologies.
Generating Random Parallel Test Forms Using CTT in a Computer-Based Environment.
ERIC Educational Resources Information Center
Weiner, John A.; Gibson, Wade M.
1998-01-01
Describes a procedure for automated-test-forms assembly based on Classical Test Theory (CTT). The procedure uses stratified random-content sampling and test-form preequating to ensure both content and psychometric equivalence in generating virtually unlimited parallel forms. Extends the usefulness of CTT in automated test construction. (Author/SLD)
Spectral turning bands for efficient Gaussian random fields generation on GPUs and accelerators
NASA Astrophysics Data System (ADS)
Hunger, L.; Cosenza, B.; Kimeswenger, S.; Fahringer, T.
2015-11-01
A random field (RF) is a set of correlated random variables associated with different spatial locations. RF generation algorithms are of crucial importance for many scientific areas, such as astrophysics, geostatistics, computer graphics, and many others. Current approaches commonly make use of 3D fast Fourier transform (FFT), which does not scale well for RF bigger than the available memory; they are also limited to regular rectilinear meshes. We introduce random field generation with the turning band method (RAFT), an RF generation algorithm based on the turning band method that is optimized for massively parallel hardware such as GPUs and accelerators. Our algorithm replaces the 3D FFT with a lower-order, one-dimensional FFT followed by a projection step and is further optimized with loop unrolling and blocking. RAFT can easily generate RF on non-regular (non-uniform) meshes and efficiently produce fields with mesh sizes bigger than the available device memory by using a streaming, out-of-core approach. Our algorithm generates RF with the correct statistical behavior and is tested on a variety of modern hardware, such as NVIDIA Tesla, AMD FirePro and Intel Phi. RAFT is faster than the traditional methods on regular meshes and has been successfully applied to two real case scenarios: planetary nebulae and cosmological simulations.
NASA Astrophysics Data System (ADS)
ajansen; kwhitefoot; panteltje1; edprochak; sudhakar, the
2014-07-01
In reply to the physicsworld.com news story “How to make a quantum random-number generator from a mobile phone” (16 May, http://ow.ly/xFiYc, see also p5), which describes a way of delivering random numbers by counting the number of photons that impinge on each of the individual pixels in the camera of a Nokia N9 smartphone.
Trail, Collin M; Madhok, Vaibhav; Deutsch, Ivan H
2008-10-01
We study the dynamical generation of entanglement as a signature of chaos in a system of periodically kicked coupled tops, where chaos and entanglement arise from the same physical mechanism. The long-time-averaged entanglement as a function of the position of an initially localized wave packet very closely correlates with the classical phase space surface of section--it is nearly uniform in the chaotic sea, and reproduces the detailed structure of the regular islands. The uniform value in the chaotic sea is explained by the random state conjecture. As classically chaotic dynamics take localized distributions in phase space to random distributions, quantized versions take localized coherent states to pseudorandom states in Hilbert space. Such random states are highly entangled, with an average value near that of the maximally entangled state. For a map with global chaos, we derive that value based on analytic results for the entropy of random states. For a mixed phase space, we use the Percival conjecture to identify a "chaotic subspace" of the Hilbert space. The typical entanglement, averaged over the unitarily invariant Haar measure in this subspace, agrees with the long-time-averaged entanglement for initial states in the chaotic sea. In all cases the dynamically generated entanglement is that of a random complex vector, even though the system is time-reversal invariant, and the Floquet operator is a member of the circular orthogonal ensemble.
An adaptive random search for short term generation scheduling with network constraints.
Marmolejo, J A; Velasco, Jonás; Selley, Héctor J
2017-01-01
This paper presents an adaptive random search approach to address a short term generation scheduling with network constraints, which determines the startup and shutdown schedules of thermal units over a given planning horizon. In this model, we consider the transmission network through capacity limits and line losses. The mathematical model is stated in the form of a Mixed Integer Non Linear Problem with binary variables. The proposed heuristic is a population-based method that generates a set of new potential solutions via a random search strategy. The random search is based on the Markov Chain Monte Carlo method. The main key of the proposed method is that the noise level of the random search is adaptively controlled in order to exploring and exploiting the entire search space. In order to improve the solutions, we consider coupling a local search into random search process. Several test systems are presented to evaluate the performance of the proposed heuristic. We use a commercial optimizer to compare the quality of the solutions provided by the proposed method. The solution of the proposed algorithm showed a significant reduction in computational effort with respect to the full-scale outer approximation commercial solver. Numerical results show the potential and robustness of our approach.
An adaptive random search for short term generation scheduling with network constraints
Velasco, Jonás; Selley, Héctor J.
2017-01-01
This paper presents an adaptive random search approach to address a short term generation scheduling with network constraints, which determines the startup and shutdown schedules of thermal units over a given planning horizon. In this model, we consider the transmission network through capacity limits and line losses. The mathematical model is stated in the form of a Mixed Integer Non Linear Problem with binary variables. The proposed heuristic is a population-based method that generates a set of new potential solutions via a random search strategy. The random search is based on the Markov Chain Monte Carlo method. The main key of the proposed method is that the noise level of the random search is adaptively controlled in order to exploring and exploiting the entire search space. In order to improve the solutions, we consider coupling a local search into random search process. Several test systems are presented to evaluate the performance of the proposed heuristic. We use a commercial optimizer to compare the quality of the solutions provided by the proposed method. The solution of the proposed algorithm showed a significant reduction in computational effort with respect to the full-scale outer approximation commercial solver. Numerical results show the potential and robustness of our approach. PMID:28234954
Generating Variable and Random Schedules of Reinforcement Using Microsoft Excel Macros
ERIC Educational Resources Information Center
Bancroft, Stacie L.; Bourret, Jason C.
2008-01-01
Variable reinforcement schedules are used to arrange the availability of reinforcement following varying response ratios or intervals of time. Random reinforcement schedules are subtypes of variable reinforcement schedules that can be used to arrange the availability of reinforcement at a constant probability across number of responses or time.…
ERIC Educational Resources Information Center
Reike, Dennis; Schwarz, Wolf
2016-01-01
The time required to determine the larger of 2 digits decreases with their numerical distance, and, for a given distance, increases with their magnitude (Moyer & Landauer, 1967). One detailed quantitative framework to account for these effects is provided by random walk models. These chronometric models describe how number-related noisy…
ERIC Educational Resources Information Center
Reike, Dennis; Schwarz, Wolf
2016-01-01
The time required to determine the larger of 2 digits decreases with their numerical distance, and, for a given distance, increases with their magnitude (Moyer & Landauer, 1967). One detailed quantitative framework to account for these effects is provided by random walk models. These chronometric models describe how number-related noisy…
Random walk of a swimmer in a low-Reynolds-number medium
NASA Astrophysics Data System (ADS)
Garcia, Michaël; Berti, Stefano; Peyla, Philippe; Rafaï, Salima
2011-03-01
Swimming at a micrometer scale demands particular strategies. When inertia is negligible compared to viscous forces, hydrodynamics equations are reversible in time. To achieve propulsion, microswimmers must therefore deform in a way that is not invariant under time reversal. Here, we investigate dispersal properties of the microalga Chlamydomonas reinhardtii by means of microscopy and cell tracking. We show that tracked trajectories are well modeled by a correlated random walk. This process is based on short time correlations in the direction of movement called persistence. At longer times, correlation is lost and a standard random walk characterizes the trajectories. Moreover, high-speed imaging enables us to show how the back-and-forth motion of flagella at very short times affects the statistical description of the dynamics. Finally, we show how drag forces modify the characteristics of this particular random walk.
Random walk of a swimmer in a low-Reynolds-number medium.
Garcia, Michaël; Berti, Stefano; Peyla, Philippe; Rafaï, Salima
2011-03-01
Swimming at a micrometer scale demands particular strategies. When inertia is negligible compared to viscous forces, hydrodynamics equations are reversible in time. To achieve propulsion, microswimmers must therefore deform in a way that is not invariant under time reversal. Here, we investigate dispersal properties of the microalga Chlamydomonas reinhardtii by means of microscopy and cell tracking. We show that tracked trajectories are well modeled by a correlated random walk. This process is based on short time correlations in the direction of movement called persistence. At longer times, correlation is lost and a standard random walk characterizes the trajectories. Moreover, high-speed imaging enables us to show how the back-and-forth motion of flagella at very short times affects the statistical description of the dynamics. Finally, we show how drag forces modify the characteristics of this particular random walk.
Fluctuations in sliding motion generated by independent and random actions of protein motors.
Sekimoto, K; Tawada, K
2001-01-31
We consider theoretical fluctuations in the in vitro sliding movement of individual cytoskeletal filaments generated by an ensemble of protein motors whose actions are assumed to be statistically independent and random. We show that the mean square deviation of the sliding distances of a filament for a given period of time around their average is proportional to the inverse of the filament length. This result provides a basis for an experimental test of the general assumption on the independent and random actions of protein motors.
2007-11-02
Software Encryption. Dec. 1993. Cambridge, U.K.: R. Anderson, pp. 185-190. [2] Donald E. Knuth , The Art of Computer Programming. Vol 2: Seminumer- ical...two statistical tests for keystream sequences,” Electronics Letters. 23, pp. 365-366. [3] D. E. Knuth (1998), The Art of Computer Programming. Vol. 2...combination of the linearly independent m-bit vectors. Maple An interactive computer algebra system that provides a complete mathematical environment for the
A Simple Nonperiodic Random Number Generator: A Recursive Model for the Logistic Map
1992-01-01
model such diverse phenomena as fluid turbulence, the evolution of biological populations, and the fluctuation of economic prices[4]. An excellent...symposium on Computational Fluid Mechanics, 1984 (M. Murman and L. Morino, Ed.).’ 7 1 Introduction Atmospheric flows have played a fundamental role in...solution of the Navier-Stokes equations of fluid mechanics and the statisti- cal approach geared to the analysis of averaged fluid equations
Post-processing Free Quantum Random Number Generator Based on Avalanche Photodiode Array
NASA Astrophysics Data System (ADS)
Yang, Li; Sheng-Kai, Liao; Fu-Tian, Liang; Qi, Shen; Hao, Liang; Cheng-Zhi, Peng
2016-03-01
Not Available Supported by the Chinese Academy of Sciences Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, Shanghai Branch, University of Science and Technology of China, and the National Natural Science Foundation of China under Grant No 11405172.
NASA Astrophysics Data System (ADS)
Rinberg, Anatoly; Katsikis, Georgios; Prakash, Manu
2017-09-01
The generation of droplets at low Reynolds numbers is driven by nonlinear dynamics that give rise to complex patterns concerning both the droplet-to-droplet spacing and the individual droplet sizes. Here we demonstrate an experimental system in which a time-varying energy landscape provides a periodic magnetic force that generates an array of droplets from an immiscible mixture of ferrofluid and silicone oil. The resulting droplet patterns are periodic, owing to the nature of the magnetic force, yet the droplet spacing and size can vary greatly by tuning a single bias pressure applied on the ferrofluid phase; for a given cycle period of the magnetic force, droplets can be generated either at integer multiples (1, 2, ...), or at rational fractions (3/2, 5/3, 5/2, ...) of this period with mono- or multidisperse droplet sizes. We develop a discrete-time dynamical systems model not only to reproduce the phenotypes of the observed patterns but also to provide a framework for understanding systems driven by such periodic energy landscapes.
Generation of Large Numbers of Antigen-Expressing Human Dendritic Cells Using CD14-ML Technology
Imamura, Yuya; Haruta, Miwa; Tomita, Yusuke; Matsumura, Keiko; Ikeda, Tokunori; Yuno, Akira; Hirayama, Masatoshi; Nakayama, Hideki; Mizuta, Hiroshi; Nishimura, Yasuharu; Senju, Satoru
2016-01-01
We previously reported a method to expand human monocytes through lentivirus-mediated introduction of cMYC and BMI1, and we named the monocyte-derived proliferating cells, CD14-ML. CD14-ML differentiated into functional DC (CD14-ML-DC) upon addition of IL-4, resulting in the generation of a large number of DC. One drawback of this method was the extensive donor-dependent variation in proliferation efficiency. In the current study, we found that introduction of BCL2 or LYL1 along with cMYC and BMI1 was beneficial. Using the improved method, we obtained CD14-ML from all samples, regardless of whether the donors were healthy individuals or cancer patients. In vitro stimulation of peripheral blood T cells with CD14-ML-DC that were loaded with cancer antigen-derived peptides led to the establishment of CD4+ and CD8+ T cell lines that recognized the peptides. Since CD14-ML was propagated for more than 1 month, we could readily conduct genetic modification experiments. To generate CD14-ML-DC that expressed antigenic proteins, we introduced lentiviral antigen-expression vectors and subjected the cells to 2 weeks of culture for drug-selection and expansion. The resulting antigen-expressing CD14-ML-DC successfully induced CD8+ T cell lines that were reactive to CMVpp65 or MART1/MelanA, suggesting an application in vaccination therapy. Thus, this improved method enables the generation of a sufficient number of DC for vaccination therapy from a small amount of peripheral blood from cancer patients. Information on T cell epitopes is not necessary in vaccination with cancer antigen-expressing CD14-ML-DC; therefore, all patients, irrespective of HLA type, will benefit from anti-cancer therapy based on this technology. PMID:27050553
Generation of Large Numbers of Antigen-Expressing Human Dendritic Cells Using CD14-ML Technology.
Imamura, Yuya; Haruta, Miwa; Tomita, Yusuke; Matsumura, Keiko; Ikeda, Tokunori; Yuno, Akira; Hirayama, Masatoshi; Nakayama, Hideki; Mizuta, Hiroshi; Nishimura, Yasuharu; Senju, Satoru
2016-01-01
We previously reported a method to expand human monocytes through lentivirus-mediated introduction of cMYC and BMI1, and we named the monocyte-derived proliferating cells, CD14-ML. CD14-ML differentiated into functional DC (CD14-ML-DC) upon addition of IL-4, resulting in the generation of a large number of DC. One drawback of this method was the extensive donor-dependent variation in proliferation efficiency. In the current study, we found that introduction of BCL2 or LYL1 along with cMYC and BMI1 was beneficial. Using the improved method, we obtained CD14-ML from all samples, regardless of whether the donors were healthy individuals or cancer patients. In vitro stimulation of peripheral blood T cells with CD14-ML-DC that were loaded with cancer antigen-derived peptides led to the establishment of CD4+ and CD8+ T cell lines that recognized the peptides. Since CD14-ML was propagated for more than 1 month, we could readily conduct genetic modification experiments. To generate CD14-ML-DC that expressed antigenic proteins, we introduced lentiviral antigen-expression vectors and subjected the cells to 2 weeks of culture for drug-selection and expansion. The resulting antigen-expressing CD14-ML-DC successfully induced CD8+ T cell lines that were reactive to CMVpp65 or MART1/MelanA, suggesting an application in vaccination therapy. Thus, this improved method enables the generation of a sufficient number of DC for vaccination therapy from a small amount of peripheral blood from cancer patients. Information on T cell epitopes is not necessary in vaccination with cancer antigen-expressing CD14-ML-DC; therefore, all patients, irrespective of HLA type, will benefit from anti-cancer therapy based on this technology.
Copy number variation of individual cattle genomes using next-generation sequencing
Bickhart, Derek M.; Hou, Yali; Schroeder, Steven G.; Alkan, Can; Cardone, Maria Francesca; Matukumalli, Lakshmi K.; Song, Jiuzhou; Schnabel, Robert D.; Ventura, Mario; Taylor, Jeremy F.; Garcia, Jose Fernando; Van Tassell, Curtis P.; Sonstegard, Tad S.; Eichler, Evan E.; Liu, George E.
2012-01-01
Copy number variations (CNVs) affect a wide range of phenotypic traits; however, CNVs in or near segmental duplication regions are often intractable. Using a read depth approach based on next-generation sequencing, we examined genome-wide copy number differences among five taurine (three Angus, one Holstein, and one Hereford) and one indicine (Nelore) cattle. Within mapped chromosomal sequence, we identified 1265 CNV regions comprising ∼55.6-Mbp sequence—476 of which (∼38%) have not previously been reported. We validated this sequence-based CNV call set with array comparative genomic hybridization (aCGH), quantitative PCR (qPCR), and fluorescent in situ hybridization (FISH), achieving a validation rate of 82% and a false positive rate of 8%. We further estimated absolute copy numbers for genomic segments and annotated genes in each individual. Surveys of the top 25 most variable genes revealed that the Nelore individual had the lowest copy numbers in 13 cases (∼52%, χ2 test; P-value <0.05). In contrast, genes related to pathogen- and parasite-resistance, such as CATHL4 and ULBP17, were highly duplicated in the Nelore individual relative to the taurine cattle, while genes involved in lipid transport and metabolism, including APOL3 and FABP2, were highly duplicated in the beef breeds. These CNV regions also harbor genes like BPIFA2A (BSP30A) and WC1, suggesting that some CNVs may be associated with breed-specific differences in adaptation, health, and production traits. By providing the first individualized cattle CNV and segmental duplication maps and genome-wide gene copy number estimates, we enable future CNV studies into highly duplicated regions in the cattle genome. PMID:22300768
Xi, Sixing; Wang, Xiaolei; Song, Lipei; Zhu, Zhuqing; Zhu, Bowen; Huang, Shuai; Yu, Nana; Wang, Huaying
2017-04-03
Optical image encryption, especially double-random-phase-based, is of great interest in information security. In this work, we experimentally demonstrate the security and feasibility of optical image encryption with asymmetric double random phase and computer-generated hologram (CGH) by using spatial light modulator. First of all, the encrypted image modulated by asymmetric double random phase is numerically encoded into real-value CGH. Then, the encoded real-value CGH is loaded on the spatial light modulator and optically decrypted in self-designed experimental system. Experimental decryption results are in agreement with numerical calculations under the prober/mistaken phase keys condition. This optical decryption technology opens a window of optical encryption practical application and shows great potential for digital multimedia product copyright protection and holographic false trademark.
Random Brillouin fiber laser for tunable ultra-narrow linewidth microwave generation.
Xiang, Dao; Lu, Ping; Xu, Yanping; Chen, Liang; Bao, Xiaoyi
2016-10-15
Studies about random lasing phenomena taking place in disordered structures with amplification are gaining great interest, as they can support dual wavelength lasing without cavity length restriction and, hence, the tunable beat frequency in a microwave can be created in a random cavity and be amplified for applications in the information and communication technology. Here, we present a novel random Brillouin fiber laser scheme using the stimulated Brillouin scattering as gain and strong Rayleigh scattering feedback (10 km) in the single-mode fiber. The high degree of mutual coherence between the two Stokes beams from two different lasers leads to the generation of tunable ultra-narrow linewidth microwave signals (<10 Hz at 3 dB bandwidth) with a 70 dB contrast. This offers a simple and cost-effective design for microwave sources.
dos Santos, Gisele Munhoes; Bento, Ricardo Ferreira; de Medeiros, Italo Roberto Torres; Oiticcica, Jeanne; da Silva, Eleonora Csipai; Penteado, Silvio
2014-07-23
Hearing aids with an integrated sound generator have been used to enhance the treatment of tinnitus. The main aim of this study was to verify whether the combined use of amplification and sound generator is more effective than conventional amplification alone in reducing tinnitus annoyance by means of the use of a new hearing aid with an integrated sound generator. A total of 49 patients underwent a blind randomized clinical trial. Tinnitus annoyance was measured by Tinnitus Handicap Inventory and numerical scales, and psychoacoustic measures of tinnitus were also performed. The sound generator was set at the lowest intensity capable of providing relief from tinnitus. Results showed that 62.5% of the patients presented a reduction in tinnitus annoyance in the combined fitting group and in the group with amplification alone, 78% showed a reduction. This difference between the groups was not statistically significant. © The Author(s) 2014.
Liverseed, David R.
2013-01-01
Conventional abrasive sanding generates high concentrations of particles. Depending on the substrate being abraded and exposure duration, overexposure to the particles can cause negative health effects ranging from respiratory irritation to cancer. The goal of this study was to understand the differences in particle emissions between a conventional random orbital sanding system and a self-generated vacuum random orbital sanding system with attached particle filtration bag. Particle concentrations were sampled for each system in a controlled test chamber for oak wood, chromate painted (hexavalent chromium) steel panels, and gel-coated (titanium dioxide) fiberglass panels using a Gesamtstaub-Probenahmesystem (GSP) sampler at three different locations adjacent to the sanding. Elevated concentrations were reported for all particles in the samples collected during conventional sanding. The geometric mean concentration ratios for the three substrates ranged from 320 to 4640 times greater for the conventional sanding system than the self-generated vacuum sanding system. The differences in the particle concentration generated by the two sanding systems were statistically significant with the two sample t-test (P < 0.0001) for all three substances. The data suggest that workers using conventional sanding systems could utilize the self-generated vacuum sanding system technology to potentially reduce exposure to particles and mitigate negative health effects. PMID:23065674
Liverseed, David R; Logan, Perry W; Johnson, Carl E; Morey, Sandy Z; Raynor, Peter C
2013-03-01
Conventional abrasive sanding generates high concentrations of particles. Depending on the substrate being abraded and exposure duration, overexposure to the particles can cause negative health effects ranging from respiratory irritation to cancer. The goal of this study was to understand the differences in particle emissions between a conventional random orbital sanding system and a self-generated vacuum random orbital sanding system with attached particle filtration bag. Particle concentrations were sampled for each system in a controlled test chamber for oak wood, chromate painted (hexavalent chromium) steel panels, and gel-coated (titanium dioxide) fiberglass panels using a Gesamtstaub-Probenahmesystem (GSP) sampler at three different locations adjacent to the sanding. Elevated concentrations were reported for all particles in the samples collected during conventional sanding. The geometric mean concentration ratios for the three substrates ranged from 320 to 4640 times greater for the conventional sanding system than the self-generated vacuum sanding system. The differences in the particle concentration generated by the two sanding systems were statistically significant with the two sample t-test (P < 0.0001) for all three substances. The data suggest that workers using conventional sanding systems could utilize the self-generated vacuum sanding system technology to potentially reduce exposure to particles and mitigate negative health effects.
Expected number of distinct sites visited by N random walks in the presence of an absorbing boundary
NASA Astrophysics Data System (ADS)
Larralde, Hernán; Weiss, George H.
2003-08-01
In earlier work we have studied the expected number of distinct sites (ENDS) visited by N random walkers in time t on a translationally invariant lattice. Optical applications suggest the interest in analysing the same problem for a semi-infinite lattice in three dimensions bounded by a plane of absorbing sites. We here study this problem, showing a multiplicity of time regimes, and at the longest times showing that the ENDS is proportional to Nsurdt where t is the time. In the absence of a boundary the comparable result is proportional to Nt. Thus, the boundary effect eliminates approximately surdt random walks.
Knudsen, Bodo; Miyaoka, Ricardo; Shah, Ketul; Holden, Timothy; Turk, Thomas M T; Pedro, Renato N; Kriedberg, Carly; Hinck, Bryan; Ortiz-Alvarado, Omar; Monga, Manoj
2010-03-01
To evaluate the durability of 4 next-generation flexible ureteroscopes in a randomized, multi-institutional, prospective study. Patients at 3 institutions were randomized to 1 of 4 flexible ureteroscopes: the Wolf Viper, Olympus URF-P5, Gyrus-ACMI DUR-8 Elite (DUR-8E), and Stryker FlexVision U-500. Each center used 1 scope from each manufacturer until it needed major repair (primary endpoint). Intraoperative data included total time of use, number of scope insertions through an access sheath, working time in the lower pole, number of insertions and total time for accessory instrumentation in the working channel, number of laser insertions through the working channel, and total laser energy used. A total of 175 patients were randomized. The DUR-8E experienced early catastrophic failure (< or = 10 cases) at all 3 sites; however, this also occurred at 1 site each for the Stryker and Wolf scopes. The DUR-8E required major repair after the fewest average number of cases (5.3), the lowest average total time of usage (108 minutes), the fewest insertions through an access sheath (20.3), the shortest duration of laser firing (31.3 minutes), and the shortest instrument in the working channel time (224.7 minutes). As such, due to variation in durability within manufacturers, no differences could be demonstrated. Visibility ratings for the Wolf iper were significantly better than the DUR-8E (P = .034) and the Flexvision (P = .038). The Wolf Viper, Olympus URF-P5, and Stryker Flexvision U-500 flexible ureteroscopes seem comparable with regard to durability. However, larger prospective registry-based studies are needed to document significant differences between them. 2010 Elsevier Inc. All rights reserved.
Unstructured and adaptive mesh generation for high Reynolds number viscous flows
NASA Technical Reports Server (NTRS)
Mavriplis, Dimitri J.
1991-01-01
A method for generating and adaptively refining a highly stretched unstructured mesh suitable for the computation of high-Reynolds-number viscous flows about arbitrary two-dimensional geometries was developed. The method is based on the Delaunay triangulation of a predetermined set of points and employs a local mapping in order to achieve the high stretching rates required in the boundary-layer and wake regions. The initial mesh-point distribution is determined in a geometry-adaptive manner which clusters points in regions of high curvature and sharp corners. Adaptive mesh refinement is achieved by adding new points in regions of large flow gradients, and locally retriangulating; thus, obviating the need for global mesh regeneration. Initial and adapted meshes about complex multi-element airfoil geometries are shown and compressible flow solutions are computed on these meshes.
Efficient Generation of Large Number-Path Entanglement Using Only Linear Optics and Feed-Forward
Cable, Hugo; Dowling, Jonathan P.
2007-10-19
We show how an idealized measurement procedure can condense photons from two modes into one and how, by feeding forward the results of the measurement, it is possible to generate efficiently superposition states commonly called N00N states. For the basic procedure sources of number states leak onto a beam splitter, and the output ports are monitored by photodetectors. We find that detecting a fixed fraction of the input at one output port suffices to direct the remainder to the same port, with high probability, however large the initial state. When instead photons are detected at both ports, macroscopic quantum superposition states are produced. We describe a linear-optical circuit for making the components of such a state orthogonal, and another to convert the output to a N00N state. Our approach scales exponentially better than existing proposals. Important applications include quantum imaging and metrology.
2012-01-01
In the Scandinavian Prostate Cancer Group Trial Number 4 (SPCG-4), 347 men were randomly assigned to radical prostatectomy and 348 to watchful waiting. In the most recent analysis (median follow-up time = 12.8 years), the cumulative mortality curves had been stable over the follow-up. At 15 years, the absolute risk reduction of dying from prostate cancer was 6.1% following randomization to radical prostatectomy, compared with watchful waiting. Hence, 17 need to be randomized to operation to avert one death. Data on self-reported symptoms, stress from symptoms, and quality of life were collected at 4 and 12.2 years of median follow-up. These questionnaire studies show an intricate pattern of symptoms evolving after surgery, hormonal treatments, signs of tumor progression, and also from natural aging. This article discusses some of the main findings of the SPCG-4 study. PMID:23271778
Kowacs, Tanja; O'Reilly, Laura; Pan, Qing; Huijser, Annemarie; Lang, Philipp; Rau, Sven; Browne, Wesley R; Pryce, Mary T; Vos, Johannes G
2016-03-21
The photocatalytic generation of hydrogen (H2) from protons by two cyclometalated ruthenium-platinum polypyridyl complexes, [Ru(bpy)2(2,5-bpp)PtIS](2+) (1) and [Ru(dceb)2(2,5-bpp)PtIS](2+) (2) [where bpy = 2,2'-bipyridine, 2,5-bpp = 2,2',5',2″-terpyridine, dceb = 4,4'-di(carboxyethyl)bipyridine, and S = solvent], is reported. Turnover numbers (TONs) for H2 generation were increased by nearly an order of magnitude by the introduction of carboxyethyl ester units, i.e., from 80 for 1P to 650 for 2P after 6 h of irradiation, with an early turnover frequency (TOF) increasing from 15 to 200 h(-1). The TON and TOF values for 2P are among the highest reported to date for supramolecular photocatalysts. The increase correlates with stabilization of the excited states localized on the peripheral ligands of the light-harvesting Ru(II) center.
Near field development of artificially generated high Reynolds number turbulent boundary layers
NASA Astrophysics Data System (ADS)
Rodríguez-López, Eduardo; Bruce, Paul J. K.; Buxton, Oliver R. H.
2016-11-01
Particle image velocimetry is conducted in the near field of two distinct wall-mounted trips for the artificial generation of a high Reynolds number turbulent boundary layer. The first of these trips consists of high aspect ratio obstacles, which are supposed to minimize the influence of their wakes on the near-wall region, contrasting with low aspect ratio trips, which would enhance this influence. A comprehensive study involving flow description, turbulent-nonturbulent interface detection, a low-order model description of the flow and an exploration of the influence of the wake in the near-wall region is conducted and two different mechanisms are clearly identified and described. First, high aspect ratio trips generate a wall-driven mechanism whose characteristics are a thinner, sharper, and less tortuous turbulent-nonturbulent interface and a reduced influence of the trips' wake in the near-wall region. Second, low aspect ratio trips generate a wake-driven mechanisms in which their turbulent-nonturbulent interface is thicker, less sharply defined, and with a higher tortuosity and the detached wake of the obstacles presents a significant influence on the near-wall region. Study of the low-order modeling of the flow field suggests that these two mechanisms may not be exclusive to the particular geometries tested in the present study but, on the contrary, can be explained based on the predominant flow features. In particular, the distinction of these two mechanisms can explain some of the trends that have appeared in the literature in the past decades.
NASA Astrophysics Data System (ADS)
Pohle, Ina; Niebisch, Michael; Zha, Tingting; Schümberg, Sabine; Müller, Hannes; Maurer, Thomas; Hinz, Christoph
2017-04-01
Rainfall variability within a storm is of major importance for fast hydrological processes, e.g. surface runoff, erosion and solute dissipation from surface soils. To investigate and simulate the impacts of within-storm variabilities on these processes, long time series of rainfall with high resolution are required. Yet, observed precipitation records of hourly or higher resolution are in most cases available only for a small number of stations and only for a few years. To obtain long time series of alternating rainfall events and interstorm periods while conserving the statistics of observed rainfall events, the Poisson model can be used. Multiplicative microcanonical random cascades have been widely applied to disaggregate rainfall time series from coarse to fine temporal resolution. We present a new coupling approach of the Poisson rectangular pulse model and the multiplicative microcanonical random cascade model that preserves the characteristics of rainfall events as well as inter-storm periods. In the first step, a Poisson rectangular pulse model is applied to generate discrete rainfall events (duration and mean intensity) and inter-storm periods (duration). The rainfall events are subsequently disaggregated to high-resolution time series (user-specified, e.g. 10 min resolution) by a multiplicative microcanonical random cascade model. One of the challenges of coupling these models is to parameterize the cascade model for the event durations generated by the Poisson model. In fact, the cascade model is best suited to downscale rainfall data with constant time step such as daily precipitation data. Without starting from a fixed time step duration (e.g. daily), the disaggregation of events requires some modifications of the multiplicative microcanonical random cascade model proposed by Olsson (1998): Firstly, the parameterization of the cascade model for events of different durations requires continuous functions for the probabilities of the multiplicative
Turbulence statistics downstream of a vorticity generator at low Reynolds numbers
NASA Astrophysics Data System (ADS)
Habchi, Charbel; Lemenand, Thierry; Della Valle, Dominique; Peerhossaini, Hassan
2016-10-01
Vortex generators (VGs) are inserted in turbulent pipe flows in order to improve mixing and heat and mass transfer while a moderate pressure drop is maintained. The purpose of the present study is to contribute to the elaboration of scaling laws for the turbulence decay downstream a row of VGs. This knowledge will help in the design of such systems, especially for optimal geometry and spacing of the VG. The experimental study is carried out using laser Doppler anemometry at different locations downstream of the row of VGs so as to probe the streamwise velocity field. The Taylor microscale Reynolds number Reλ ranges between 15 and 80 so that, for the lowest flow rates, fully developed turbulence conditions are not fulfilled. Comparison of the integral length scale to data in the open literature shows that the conventional scaling laws at the dissipative scale are fairly assessed. It is shown that the turbulence macroscale increases in the streamwise direction and is scaled by the VG dimensions. The normalized turbulent energy dissipation rate has values between 0.5 and 2.8, with -1 power-law decay as a function of the Taylor microscale Reynolds number. This observation is consistent with previous findings using direct numerical simulations (DNS). The streamwise variation of the turbulence energy dissipation rate shows an exponential decay; it reaches an asymptotic value after a distance of about 6 times the VG height.
Structure Generation and Analysis from the Loosest to the Densest Random Packings
NASA Astrophysics Data System (ADS)
Delaney, Gary W.
2017-06-01
We explore sets of jammed packings of frictional spheres and ellipsoids generated using the Discrete Element Method. A novel preparation method is presented and analysed, where the internal structure of the system is modified by iteratively removing grains to generate a continuous variation in packing fraction from the densest to the loosest mechanically stable systems. We present a number of measures quantifying the variation in the structure of the system as grains are removed, including the variation in packing fraction, distribution of grain contact numbers, degree of orientational ordering and the degree of displacements of the grains due to rearrangements to achieve mechanical stability after a grain is removed.
Dependent online kernel learning with constant number of random Fourier features.
Hu, Zhen; Lin, Ming; Zhang, Changshui
2015-10-01
Traditional online kernel learning analysis assumes independently identically distributed (i.i.d.) about the training sequence. Recent studies reveal that when the loss function is smooth and strongly convex, given T i.i.d. training instances, a constant sampling complexity of random Fourier features is sufficient to ensure O(logT/T) convergence rate of excess risk, which is optimal in online kernel learning up to a logT factor. However, the i.i.d. hypothesis is too strong in practice, which greatly impairs their value. In this paper, we study the sampling complexity of random Fourier features in online kernel learning under non-i.i.d. assumptions. We prove that the sampling complexity under non-i.i.d. settings is also constant, but the convergence rate of excess risk is O(logT/T+ ϕ) , where ϕ is the mixing coefficient measuring the extent of non-i.i.d. of training sequence. We conduct experiments both on artificial and real large-scale data sets to verify our theories.
Topographic height dependence of internal wave generation by tidal flow over random topography
NASA Astrophysics Data System (ADS)
Zhao, Jiajun; Zhang, Likun; Swinney, Harry L.
2015-10-01
Internal waves (IWs) generated by tidal flow over the seafloor play a critical role in ocean circulation and climate. We determine the dependence of the radiated IW power on topographic parameters in numerical simulations of tidal flow over two-dimensional random topographic profiles that have the spectrum of oceanic abyssal hills. The IW power increases as the horizontal spatial resolution scale is decreased, but below a certain spatial scale the power saturates at a level less than the linear theory prediction. For increasing topographic RMS height Hrms the emergent interference of the tide and the IWs from different generation sites leads to a transition in the IW power dependence on Hrms from quadratic to linear. This transition in the scaling of the IW power depends on the slopes of a valley's nearest neighboring peaks. Our results should guide the modeling of IW generation by tidal flow over small-scale ocean topography.
NASA Astrophysics Data System (ADS)
Tomita, Toshihiro; Miyaji, Kousuke
2016-04-01
The dependence of random telegraph noise (RTN) amplitude distribution on the number of traps and trap depth position is investigated using three-dimensional Monte Carlo device simulation including random dopant fluctuation (RDF) in a 30 nm NAND multi level flash memory. The ΔV th tail distribution becomes broad at fixed double traps, indicating that the number of traps greatly affects the worst RTN characteristics. It is also found that for both fixed single and fixed double traps, the ΔV th distribution in the lowest cell threshold voltage (V th) state shows the broadest distribution among all cell V th states. This is because the drain current flows at the channel surface in the lowest cell V th state, while at a high cell V th, it flows at the deeper position owing to the fringing coupling between the control gate (CG) and the channel. In this work, the ΔV th distribution with the number of traps following the Poisson distribution is also considered to cope with the variations in trap number. As a result, it is found that the number of traps is an important factor for understanding RTN characteristics. In addition, considering trap position in the tunnel oxide thickness direction is also an important factor.
Theory and generation of conditional, scalable sub-Gaussian random fields
NASA Astrophysics Data System (ADS)
Panzeri, M.; Riva, M.; Guadagnini, A.; Neuman, S. P.
2016-03-01
Many earth and environmental (as well as a host of other) variables, Y, and their spatial (or temporal) increments, ΔY, exhibit non-Gaussian statistical scaling. Previously we were able to capture key aspects of such non-Gaussian scaling by treating Y and/or ΔY as sub-Gaussian random fields (or processes). This however left unaddressed the empirical finding that whereas sample frequency distributions of Y tend to display relatively mild non-Gaussian peaks and tails, those of ΔY often reveal peaks that grow sharper and tails that become heavier with decreasing separation distance or lag. Recently we proposed a generalized sub-Gaussian model (GSG) which resolves this apparent inconsistency between the statistical scaling behaviors of observed variables and their increments. We presented an algorithm to generate unconditional random realizations of statistically isotropic or anisotropic GSG functions and illustrated it in two dimensions. Most importantly, we demonstrated the feasibility of estimating all parameters of a GSG model underlying a single realization of Y by analyzing jointly spatial moments of Y data and corresponding increments, ΔY. Here, we extend our GSG model to account for noisy measurements of Y at a discrete set of points in space (or time), present an algorithm to generate conditional realizations of corresponding isotropic or anisotropic random fields, introduce two approximate versions of this algorithm to reduce CPU time, and explore them on one and two-dimensional synthetic test cases.
NASA Technical Reports Server (NTRS)
Over, Thomas, M.; Gupta, Vijay K.
1994-01-01
Under the theory of independent and identically distributed random cascades, the probability distribution of the cascade generator determines the spatial and the ensemble properties of spatial rainfall. Three sets of radar-derived rainfall data in space and time are analyzed to estimate the probability distribution of the generator. A detailed comparison between instantaneous scans of spatial rainfall and simulated cascades using the scaling properties of the marginal moments is carried out. This comparison highlights important similarities and differences between the data and the random cascade theory. Differences are quantified and measured for the three datasets. Evidence is presented to show that the scaling properties of the rainfall can be captured to the first order by a random cascade with a single parameter. The dependence of this parameter on forcing by the large-scale meteorological conditions, as measured by the large-scale spatial average rain rate, is investigated for these three datasets. The data show that this dependence can be captured by a one-to-one function. Since the large-scale average rain rate can be diagnosed from the large-scale dynamics, this relationship demonstrates an important linkage between the large-scale atmospheric dynamics and the statistical cascade theory of mesoscale rainfall. Potential application of this research to parameterization of runoff from the land surface and regional flood frequency analysis is briefly discussed, and open problems for further research are presented.
Thermodynamic method for generating random stress distributions on an earthquake fault
Barall, Michael; Harris, Ruth A.
2012-01-01
This report presents a new method for generating random stress distributions on an earthquake fault, suitable for use as initial conditions in a dynamic rupture simulation. The method employs concepts from thermodynamics and statistical mechanics. A pattern of fault slip is considered to be analogous to a micro-state of a thermodynamic system. The energy of the micro-state is taken to be the elastic energy stored in the surrounding medium. Then, the Boltzmann distribution gives the probability of a given pattern of fault slip and stress. We show how to decompose the system into independent degrees of freedom, which makes it computationally feasible to select a random state. However, due to the equipartition theorem, straightforward application of the Boltzmann distribution leads to a divergence which predicts infinite stress. To avoid equipartition, we show that the finite strength of the fault acts to restrict the possible states of the system. By analyzing a set of earthquake scaling relations, we derive a new formula for the expected power spectral density of the stress distribution, which allows us to construct a computer algorithm free of infinities. We then present a new technique for controlling the extent of the rupture by generating a random stress distribution thousands of times larger than the fault surface, and selecting a portion which, by chance, has a positive stress perturbation of the desired size. Finally, we present a new two-stage nucleation method that combines a small zone of forced rupture with a larger zone of reduced fracture energy.
ERIC Educational Resources Information Center
Fuchs, Lynn S.; Powell, Sarah R.; Seethaler, Pamela M.; Cirino, Paul T.; Fletcher, Jack M.; Fuchs, Douglas; Hamlett, Carol L.; Zumeta, Rebecca O.
2009-01-01
The purposes of this study were to assess the efficacy of remedial tutoring for 3rd graders with mathematics difficulty, to investigate whether tutoring is differentially efficacious depending on students' math difficulty status (mathematics difficulty alone vs. mathematics plus reading difficulty), to explore transfer from number combination (NC)…
He, Chao-Zhu; Zhang, Kun-He; Wang, Ting; Wan, Qin-Si; Hu, Piao-Ping; Hu, Mei-Di; Huang, De-Qiang; Lv, Nong-Hua
2013-09-01
The amplification of a random single-stranded DNA (ssDNA) library by polymerase chain reaction (PCR) is a key step in each round of aptamer selection by systematic evolution of ligands by exponential enrichment (SELEX), but it can be impeded by the amplification of by-products due to the severely nonspecific hybridizations among various sequences in the PCR system. To amplify a random ssDNA library free from by-products, we developed a novel method termed single-primer-limited amplification (SPLA), which was initiated from the amplification of minus-stranded DNA (msDNA) of an ssDNA library with reverse primer limited to 5-fold molar quantity of the template, followed by the amplification of plus-stranded DNA (psDNA) of the msDNA with forward primer limited to 10-fold molar quantity of the template and recovery of psDNA by gel excision. We found that the amount of by-products increased with the increase of template amount and thermal cycle number. With the optimized template amount and thermal cycle, SPLA could amplify target ssDNA without detectable by-products and nonspecific products and could produce psDNA 16.1 times as much as that by asymmetric PCR. In conclusion, SPLA is a simple and feasible method to efficiently generate a random ssDNA sub-library for aptamer selection.
On the Formation Mechanisms of Artificially Generated High Reynolds Number Turbulent Boundary Layers
NASA Astrophysics Data System (ADS)
Rodríguez-López, Eduardo; Bruce, Paul J. K.; Buxton, Oliver R. H.
2016-08-01
We investigate the evolution of an artificially thick turbulent boundary layer generated by two families of small obstacles (divided into uniform and non-uniform wall normal distributions of blockage). One- and two-point velocity measurements using constant temperature anemometry show that the canonical behaviour of a boundary layer is recovered after an adaptation region downstream of the trips presenting 150~% higher momentum thickness (or equivalently, Reynolds number) than the natural case for the same downstream distance (x≈ 3 m). The effect of the degree of immersion of the trips for h/δ ≳ 1 is shown to play a secondary role. The one-point diagnostic quantities used to assess the degree of recovery of the canonical properties are the friction coefficient (representative of the inner motions), the shape factor and wake parameter (representative of the wake regions); they provide a severe test to be applied to artificially generated boundary layers. Simultaneous two-point velocity measurements of both spanwise and wall-normal correlations and the modulation of inner velocity by the outer structures show that there are two different formation mechanisms for the boundary layer. The trips with high aspect ratio and uniform distributed blockage leave the inner motions of the boundary layer relatively undisturbed, which subsequently drive the mixing of the obstacles' wake with the wall-bounded flow (wall-driven). In contrast, the low aspect-ratio trips with non-uniform blockage destroy the inner structures, which are then re-formed further downstream under the influence of the wake of the trips (wake-driven).
CRISPR transcript processing: a mechanism for generating a large number of small interfering RNAs
2012-01-01
Background CRISPR/Cas (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated sequences) is a recently discovered prokaryotic defense system against foreign DNA, including viruses and plasmids. CRISPR cassette is transcribed as a continuous transcript (pre-crRNA), which is processed by Cas proteins into small RNA molecules (crRNAs) that are responsible for defense against invading viruses. Experiments in E. coli report that overexpression of cas genes generates a large number of crRNAs, from only few pre-crRNAs. Results We here develop a minimal model of CRISPR processing, which we parameterize based on available experimental data. From the model, we show that the system can generate a large amount of crRNAs, based on only a small decrease in the amount of pre-crRNAs. The relationship between the decrease of pre-crRNAs and the increase of crRNAs corresponds to strong linear amplification. Interestingly, this strong amplification crucially depends on fast non-specific degradation of pre-crRNA by an unidentified nuclease. We show that overexpression of cas genes above a certain level does not result in further increase of crRNA, but that this saturation can be relieved if the rate of CRISPR transcription is increased. We furthermore show that a small increase of CRISPR transcription rate can substantially decrease the extent of cas gene activation necessary to achieve a desired amount of crRNA. Conclusions The simple mathematical model developed here is able to explain existing experimental observations on CRISPR transcript processing in Escherichia coli. The model shows that a competition between specific pre-crRNA processing and non-specific degradation determines the steady-state levels of crRNA and is responsible for strong linear amplification of crRNAs when cas genes are overexpressed. The model further shows how disappearance of only a few pre-crRNA molecules normally present in the cell can lead to a large (two orders of magnitude
CRISPR transcript processing: a mechanism for generating a large number of small interfering RNAs.
Djordjevic, Marko; Djordjevic, Magdalena; Severinov, Konstantin
2012-07-31
CRISPR/Cas (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated sequences) is a recently discovered prokaryotic defense system against foreign DNA, including viruses and plasmids. CRISPR cassette is transcribed as a continuous transcript (pre-crRNA), which is processed by Cas proteins into small RNA molecules (crRNAs) that are responsible for defense against invading viruses. Experiments in E. coli report that overexpression of cas genes generates a large number of crRNAs, from only few pre-crRNAs. We here develop a minimal model of CRISPR processing, which we parameterize based on available experimental data. From the model, we show that the system can generate a large amount of crRNAs, based on only a small decrease in the amount of pre-crRNAs. The relationship between the decrease of pre-crRNAs and the increase of crRNAs corresponds to strong linear amplification. Interestingly, this strong amplification crucially depends on fast non-specific degradation of pre-crRNA by an unidentified nuclease. We show that overexpression of cas genes above a certain level does not result in further increase of crRNA, but that this saturation can be relieved if the rate of CRISPR transcription is increased. We furthermore show that a small increase of CRISPR transcription rate can substantially decrease the extent of cas gene activation necessary to achieve a desired amount of crRNA. The simple mathematical model developed here is able to explain existing experimental observations on CRISPR transcript processing in Escherichia coli. The model shows that a competition between specific pre-crRNA processing and non-specific degradation determines the steady-state levels of crRNA and is responsible for strong linear amplification of crRNAs when cas genes are overexpressed. The model further shows how disappearance of only a few pre-crRNA molecules normally present in the cell can lead to a large (two orders of magnitude) increase of crRNAs upon cas
Device-Independent Randomness Generation in the Presence of Weak Cross-Talk
NASA Astrophysics Data System (ADS)
Silman, J.; Pironio, S.; Massar, S.
2013-03-01
Device-independent protocols use nonlocality to certify that they are performing properly. This is achieved via Bell experiments on entangled quantum systems, which are kept isolated from one another during the measurements. However, with present-day technology, perfect isolation comes at the price of experimental complexity and extremely low data rates. Here we argue that for device-independent randomness generation—and other device-independent protocols where the devices are in the same lab—we can slightly relax the requirement of perfect isolation and still retain most of the advantages of the device-independent approach, by allowing a little cross-talk between the devices. This opens up the possibility of using existent experimental systems with high data rates, such as Josephson phase qubits on the same chip, thereby bringing device-independent randomness generation much closer to practical application.
NASA Astrophysics Data System (ADS)
Xi, Si-xing; Wang, Xiaolei; Sun, Xin; Chang, Shengjiang; Lin, Lie
2014-01-01
We propose a new method of image encryption using Fourier computer-generated hologram (CGH) in the encryption system of multiple Fresnel diffraction transforms with phase masks. The digital image to be encrypted is modulated by a series of three random-phase masks in Fresnel diffraction system and finally is transformed into a complex-amplitude image which is stationary white noise (in which the information is like stationary-white-noise). Because the complex-amplitude information is not easy to be directly saved, the binary real value Fourier CGH is applied to record it. Compared with the traditional double random-phase image encryption technology, this method adds new keys which enhance the image encryption security and the Fourier CGH greatly improves the antinoise performance.
NASA Astrophysics Data System (ADS)
Staber, Brian; Guilleminot, Johann
2017-06-01
In this Note, we present a unified approach to the information-theoretic modeling and simulation of a class of elasticity random fields, for all physical symmetry classes. The new stochastic representation builds upon a Walpole tensor decomposition, which allows the maximum entropy constraints to be decoupled in accordance with the tensor (sub)algebras associated with the class under consideration. In contrast to previous works where the construction was carried out on the scalar-valued Walpole coordinates, the proposed strategy involves both matrix-valued and scalar-valued random fields. This enables, in particular, the construction of a generation algorithm based on a memoryless transformation, hence improving the computational efficiency of the framework. Two applications involving weak symmetries and sampling over spherical and cylindrical geometries are subsequently provided. These numerical experiments are relevant to the modeling of elastic interphases in nanocomposites, as well as to the simulation of spatially dependent wood properties for instance.
Maglennon, Gareth A; Cook, Beth S; Deeney, Alannah S; Bossé, Janine T; Peters, Sarah E; Langford, Paul R; Maskell, Duncan J; Tucker, Alexander W; Wren, Brendan W; Rycroft, Andrew N
2013-12-21
Mycoplasma hyopneumoniae is the cause of enzootic pneumonia in pigs, a chronic respiratory disease associated with significant economic losses to swine producers worldwide. The molecular pathogenesis of infection is poorly understood due to the lack of genetic tools to allow manipulation of the organism and more generally for the Mycoplasma genus. The objective of this study was to develop a system for generating random transposon insertion mutants in M. hyopneumoniae that could prove a powerful tool in enabling the pathogenesis of infection to be unraveled. A novel delivery vector was constructed containing a hyperactive C9 mutant of the Himar1 transposase along with a mini transposon containing the tetracycline resistance cassette, tetM. M. hyopneumoniae strain 232 was electroporated with the construct and tetM-expressing transformants selected on agar containing tetracycline. Individual transformants contained single transposon insertions that were stable upon serial passages in broth medium. The insertion sites of 44 individual transformants were determined and confirmed disruption of several M. hyopneumoniae genes. A large pool of over 10 000 mutants was generated that should allow saturation of the M. hyopneumoniae strain 232 genome. This is the first time that transposon mutagenesis has been demonstrated in this important pathogen and could be generally applied for other Mycoplasma species that are intractable to genetic manipulation. The ability to generate random mutant libraries is a powerful tool in the further study of the pathogenesis of this important swine pathogen.
Efficient cascaded generation of narrowband linearly-polarized radiation in random Raman fiber laser
NASA Astrophysics Data System (ADS)
Babin, Sergey A.; Zlobina, Ekaterina A.; Kablukov, Sergey I.; Podivilov, Evgeniy V.
2016-03-01
We demonstrate a linearly-polarized high efficiency random Raman lasing of the 1st-order Stokes wave and cascaded generation in 0.5- and 1-km-long PM fiber, respectively, under polarized pumping. Quantum efficiency of converting input pump radiation (1.05μm) into the 1st (1.11μm), 2nd (1.17μm) and 3rd-order (1.23μm) Stokes waves is about 80% in the cascaded generation, regardless of the order, and amounts to 92% for the 1st-order Stokes wave in the 0.5-km PM fiber. Polarization extinction ratio is >22 dB for all the waves at output powers of up to 10 W. An analytical model describing adequately the generated power for all components of the cascaded random Raman fiber laser has been developed. The laser bandwidth increases with Stokes order, amounting to ~1, ~2 and ~3 nm for the consecutive orders, respectively.
Tang, Xi; Wu, Zheng-Mao; Wu, Jia-Gui; Deng, Tao; Chen, Jian-Jun; Fan, Li; Zhong, Zhu-Qiang; Xia, Guang-Qiong
2015-12-28
Using two mutually coupled semiconductor lasers (MC-SLs) outputs as chaotic entropy sources, a scheme for generating Tbits/s ultra-fast physical random bit (PRB) is demonstrated and analyzed experimentally. Firstly, two entropy sources originating from two chaotic outputs of MC-SLs are obtained in parallel. Secondly, by adopting multiple optimized post-processing methods, two PRB streams with the generation rate of 0.56 Tbits/s are extracted from the two entropy sources and their randomness are verified by using NIST Special Publication 800-22 statistical tests. Through merging the two sets of 0.56 Tbits/s PRB streams by an interleaving operation, a third set of 1.12 Tbits/s PRB stream, which meets all the quality criteria of NIST statistical tests, can be further acquired. Finally, after additionally taking into account the restriction of the min-entropy, the generation rate of two sets of PRB stream from the two entropy sources can still attain 0.48 Tbits/s, and then a third set of merging PRB stream is 0.96 Tbits/s. Moreover, for the sequence length of the order of 10 Gbits, the statistical bias and serial correlation coefficient of three sets of PRB streams are also analyzed.
Venkataraman, Narayan; Ulfarsson, Gudmundur F; Shankar, Venky N
2013-10-01
A nine-year (1999-2007) continuous panel of crash histories on interstates in Washington State, USA, was used to estimate random parameter negative binomial (RPNB) models for various aggregations of crashes. A total of 21 different models were assessed in terms of four ways to aggregate crashes, by: (a) severity, (b) number of vehicles involved, (c) crash type, and by (d) location characteristics. The models within these aggregations include specifications for all severities (property damage only, possible injury, evident injury, disabling injury, and fatality), number of vehicles involved (one-vehicle to five-or-more-vehicle), crash type (sideswipe, same direction, overturn, head-on, fixed object, rear-end, and other), and location types (urban interchange, rural interchange, urban non-interchange, rural non-interchange). A total of 1153 directional road segments comprising of the seven Washington State interstates were analyzed, yielding statistical models of crash frequency based on 10,377 observations. These results suggest that in general there was a significant improvement in log-likelihood when using RPNB compared to a fixed parameter negative binomial baseline model. Heterogeneity effects are most noticeable for lighting type, road curvature, and traffic volume (ADT). Median lighting or right-side lighting are linked to increased crash frequencies in many models for more than half of the road segments compared to both-sides lighting. Both-sides lighting thereby appears to generally lead to a safety improvement. Traffic volume has a random parameter but the effect is always toward increasing crash frequencies as expected. However that the effect is random shows that the effect of traffic volume on crash frequency is complex and varies by road segment. The number of lanes has a random parameter effect only in the interchange type models. The results show that road segment-specific insights into crash frequency occurrence can lead to improved design policy and
Using the Cre-lox system to randomize target gene expression states and generate diverse phenotypes
Niesner, Bradley; Maheshri, Narendra
2013-01-01
Modifying the expression of multiple genes enables both deeper understanding of their function and the engineering of complex multigenic cellular phenotypes. However, deletion or overexpression of multiple genes can be laborious and involves multiple sequential genetic modifications. Here we describe a strategy to randomize the expression state of multiple genes in S. cerevisiae using Cre-loxP recombination. By inserting promoters flanked by inverted loxP sites in front of a gene of interest we can randomly turn it OFF or ON, or between 4 distinct expression states. We show at least 6 genes can be randomized independently and argue that using orthogonal loxP sites should increase this number to at least 15. Finally, we show how combining this strategy with mating allows easy introduction of native regulation as an additional expression state and use this to probe the role of 4 different enzymes involved in base excision repair in tolerate exposure to methyl methane sulfonate (MMS), a genotoxic DNA alkylating agent. The set of vectors developed here can be used to randomize the expression of both heterologous genes and endogenous genes, and could immediately prove useful for metabolic engineering in yeast. Because Cre-loxP recombination works in many organisms, this strategy should be readily extendable. PMID:23733452
Generation of optical 'Schrödinger cats' from photon number states.
Ourjoumtsev, Alexei; Jeong, Hyunseok; Tualle-Brouri, Rosa; Grangier, Philippe
2007-08-16
Schrödinger's cat is a Gedankenexperiment in quantum physics, in which an atomic decay triggers the death of the cat. Because quantum physics allow atoms to remain in superpositions of states, the classical cat would then be simultaneously dead and alive. By analogy, a 'cat' state of freely propagating light can be defined as a quantum superposition of well separated quasi-classical states-it is a classical light wave that simultaneously possesses two opposite phases. Such states play an important role in fundamental tests of quantum theory and in many quantum information processing tasks, including quantum computation, quantum teleportation and precision measurements. Recently, optical Schrödinger 'kittens' were prepared; however, they are too small for most of the aforementioned applications and increasing their size is experimentally challenging. Here we demonstrate, theoretically and experimentally, a protocol that allows the generation of arbitrarily large squeezed Schrödinger cat states, using homodyne detection and photon number states as resources. We implemented this protocol with light pulses containing two photons, producing a squeezed Schrödinger cat state with a negative Wigner function. This state clearly exhibits several quantum phase-space interference fringes between the 'dead' and 'alive' components, and is large enough to become useful for quantum information processing and experimental tests of quantum theory.
Generation of optical `Schrödinger cats' from photon number states
NASA Astrophysics Data System (ADS)
Ourjoumtsev, Alexei; Jeong, Hyunseok; Tualle-Brouri, Rosa; Grangier, Philippe
2007-08-01
Schrödinger's cat is a Gedankenexperiment in quantum physics, in which an atomic decay triggers the death of the cat. Because quantum physics allow atoms to remain in superpositions of states, the classical cat would then be simultaneously dead and alive. By analogy, a `cat' state of freely propagating light can be defined as a quantum superposition of well separated quasi-classical states-it is a classical light wave that simultaneously possesses two opposite phases. Such states play an important role in fundamental tests of quantum theory and in many quantum information processing tasks, including quantum computation, quantum teleportation and precision measurements. Recently, optical Schrödinger `kittens' were prepared; however, they are too small for most of the aforementioned applications and increasing their size is experimentally challenging. Here we demonstrate, theoretically and experimentally, a protocol that allows the generation of arbitrarily large squeezed Schrödinger cat states, using homodyne detection and photon number states as resources. We implemented this protocol with light pulses containing two photons, producing a squeezed Schrödinger cat state with a negative Wigner function. This state clearly exhibits several quantum phase-space interference fringes between the `dead' and `alive' components, and is large enough to become useful for quantum information processing and experimental tests of quantum theory.
Similar numbers of neurons are generated in the male and female rat preoptic area in utero.
Orikasa, Chitose; Kondo, Yasuhiko; Usui, Sumiko; Sakuma, Yasuo
2010-09-01
The birth date of neurons comprising the sexually dimorphic nucleus of the rat preoptic area (SDN-POA) was determined by bromodeoxyuridine (BrdU) injections at a prescribed time during the embryonic period. Calbindin immunostaining was used as a marker to identity the SDN-POA. The animals were bred from dams injected with BrdU on days 14, 16 or 18 of pregnancy (fertilization defined as day 1). On day 15 after birth (PD), all offspring were euthanized and brain sections were prepared for histology. Neurogenesis in the SDN-POA began around embryonic day (ED) 14 and culminated on ED 18, whereas the preoptic neurons surrounding the SDN-POA generated earlier than did those of the SDN-POA. Although the SDN-POA was significantly larger in males than in females at PD15, the total numbers of neurons comprising the SDN-POA were not significantly different between sexes. Similar aggregates of somatostatin mRNA-positive cells in the central portion of the SDN-POA were observed in both sexes at PD8. On PD15, the aggregates became scattered in males, whereas the aggregates in females remained congested. These data suggest that sexual dimorphism in the SDN-POA results from male-specific postnatal radial spreading of cells rather than cell proliferation during embryonic neurogenesis. 2010 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.
Morrill, André; Forbes, Mark R
2012-06-01
Parasite aggregation is viewed as a natural law in parasite-host ecology but is a paradox insofar as parasites should follow the Poisson distribution if hosts are encountered randomly. Much research has focused on whether parasite aggregation in or on hosts is explained by aggregation of infective parasite stages in the environment, or by heterogeneity within host samples in terms of host responses to infection (e.g., through representation of different age classes of hosts). In this paper, we argue that the typically aggregated distributions of parasites may be explained simply. We propose that aggregated distributions can be derived from parasites encountering hosts randomly, but subsequently by parasites being 'lost' from hosts based on condition-linked escape or immunity of hosts. Host condition should be a normally distributed trait even among otherwise homogeneous sets of hosts. Our model shows that mean host condition and variation in host condition have different effects on the different metrics of parasite aggregation. Our model further predicts that as host condition increases, parasites become more aggregated but numbers of attending parasites are reduced overall and this is important for parasite population dynamics. The effects of deviation from random encounter are discussed with respect to the relationship between host condition and final parasite numbers.
A random approach of test macro generation for early detection of hotspots
NASA Astrophysics Data System (ADS)
Lee, Jong-hyun; Kim, Chin; Kang, Minsoo; Hwang, Sungwook; Yang, Jae-seok; Harb, Mohammed; Al-Imam, Mohamed; Madkour, Kareem; ElManhawy, Wael; Kwan, Joe
2016-03-01
Multiple-Patterning Technology (MPT) is still the preferred choice over EUV for the advanced technology nodes, starting the 20nm node. Down the way to 7nm and 5nm nodes, Self-Aligned Multiple Patterning (SAMP) appears to be one of the effective multiple patterning techniques in terms of achieving small pitch of printed lines on wafer, yet its yield is in question. Predicting and enhancing the yield in the early stages of technology development are some of the main objectives for creating test macros on test masks. While conventional yield ramp techniques for a new technology node have relied on using designs from previous technology nodes as a starting point to identify patterns for Design of Experiment (DoE) creation, these techniques are challenging to apply in the case of introducing an MPT technique like SAMP that did not exist in previous nodes. This paper presents a new strategy for generating test structures based on random placement of unit patterns that can construct more meaningful bigger patterns. Specifications governing the relationships between those unit patterns can be adjusted to generate layout clips that look like realistic SAMP designs. A via chain can be constructed to connect the random DoE of SAMP structures through a routing layer to external pads for electrical measurement. These clips are decomposed according to the decomposition rules of the technology into the appropriate mandrel and cut masks. The decomposed clips can be tested through simulations, or electrically on silicon to discover hotspots. The hotspots can be used in optimizing the fabrication process and models to fix them. They can also be used as learning patterns for DFM deck development. By expanding the size of the randomly generated test structures, more hotspots can be detected. This should provide a faster way to enhance the yield of a new technology node.
NASA Astrophysics Data System (ADS)
Feng, Ju; Shen, Wen Zhong; Xu, Chang
2016-09-01
A new algorithm for multi-objective wind farm layout optimization is presented. It formulates the wind turbine locations as continuous variables and is capable of optimizing the number of turbines and their locations in the wind farm simultaneously. Two objectives are considered. One is to maximize the total power production, which is calculated by considering the wake effects using the Jensen wake model combined with the local wind distribution. The other is to minimize the total electrical cable length. This length is assumed to be the total length of the minimal spanning tree that connects all turbines and is calculated by using Prim's algorithm. Constraints on wind farm boundary and wind turbine proximity are also considered. An ideal test case shows the proposed algorithm largely outperforms a famous multi-objective genetic algorithm (NSGA-II). In the real test case based on the Horn Rev 1 wind farm, the algorithm also obtains useful Pareto frontiers and provides a wide range of Pareto optimal layouts with different numbers of turbines for a real-life wind farm developer.
Stochastic generation of explicit pore structures by thresholding Gaussian random fields
Hyman, Jeffrey D.; Winter, C. Larrabee
2014-11-15
We provide a description and computational investigation of an efficient method to stochastically generate realistic pore structures. Smolarkiewicz and Winter introduced this specific method in pores resolving simulation of Darcy flows (Smolarkiewicz and Winter, 2010 [1]) without giving a complete formal description or analysis of the method, or indicating how to control the parameterization of the ensemble. We address both issues in this paper. The method consists of two steps. First, a realization of a correlated Gaussian field, or topography, is produced by convolving a prescribed kernel with an initial field of independent, identically distributed random variables. The intrinsic length scales of the kernel determine the correlation structure of the topography. Next, a sample pore space is generated by applying a level threshold to the Gaussian field realization: points are assigned to the void phase or the solid phase depending on whether the topography over them is above or below the threshold. Hence, the topology and geometry of the pore space depend on the form of the kernel and the level threshold. Manipulating these two user prescribed quantities allows good control of pore space observables, in particular the Minkowski functionals. Extensions of the method to generate media with multiple pore structures and preferential flow directions are also discussed. To demonstrate its usefulness, the method is used to generate a pore space with physical and hydrological properties similar to a sample of Berea sandstone. -- Graphical abstract: -- Highlights: •An efficient method to stochastically generate realistic pore structures is provided. •Samples are generated by applying a level threshold to a Gaussian field realization. •Two user prescribed quantities determine the topology and geometry of the pore space. •Multiple pore structures and preferential flow directions can be produced. •A pore space based on Berea sandstone is generated.
Random source generating far field with elliptical flat-topped beam profile
NASA Astrophysics Data System (ADS)
Zhang, Yongtao; Cai, Yangjian
2014-07-01
Circular and rectangular multi-Gaussian Schell-model (MGSM) sources which generate far fields with circular and rectangular flat-topped beam profiles were introduced just recently (Sahin and Korotkova 2012 Opt. Lett. 37 2970; Korotkova 2014 Opt. Lett. 39 64). In this paper, a random source named an elliptical MGSM source is introduced. An analytical expression for the propagation factor of an elliptical MGSM beam is derived. Furthermore, an analytical propagation formula for an elliptical MGSM beam passing through a stigmatic ABCD optical system is derived, and its propagation properties in free space are studied. It is interesting to find that an elliptical MGSM source generates a far field with an elliptical flat-topped beam profile, being qualitatively different from that of circular and rectangular MGSM sources. The ellipticity and the flatness of the elliptical flat-topped beam profile in the far field are determined by the initial coherence widths and the beam index, respectively.
On the Number of Generator Sets of the Non-Cubic Symmetry Point Groups.
ERIC Educational Resources Information Center
Kouyoumdjian, E. R.
1983-01-01
The generator set of a group is the subset of the set of elements of the group. The nature and use of generator sets is discussed, focusing on generator sets for the noncubic symmetry point groups containing one, two, and three symmetry elements. (JN)
NASA Technical Reports Server (NTRS)
Wang, Charles C.; Pei, Dingyi
1990-01-01
A VLSI design for computing exponentiation in finite fields is developed. An algorithm to generate a relatively long pseudorandom number sequence is presented. It is shown that the period of this sequence is significantly increased compared to that of the sequence generated by the most commonly used maximal length shift register scheme.
NASA Astrophysics Data System (ADS)
Galindo-Torres, S. A.; Muñoz, J. D.; Alonso-Marroquín, F.
2010-11-01
Minkowski operators (dilation and erosion of sets in vector spaces) have been extensively used in computer graphics, image processing to analyze the structure of materials, and more recently in molecular dynamics. Here, we apply those mathematical concepts to extend the discrete element method to simulate granular materials with complex-shaped particles. The Voronoi-Minkowski diagrams are introduced to generate random packings of complex-shaped particles with tunable particle roundness. Contact forces and potentials are calculated in terms of distances instead of overlaps. By using the Verlet method to detect neighborhood, we achieve CPU times that grow linearly with the body’s number of sides. Simulations of dissipative granular materials under shear demonstrate that the method maintains conservation of energy in accord with the first law of thermodynamics. A series of simulations for biaxial test, shear band formation, hysteretic behavior, and ratcheting show that the model can reproduce the main features of real granular-soil behavior.
Dictated versus database-generated discharge summaries: a randomized clinical trial
van Walraven, C; Laupacis, A; Seth, R; Wells, G
1999-01-01
BACKGROUND: Hospital discharge summaries communicate information necessary for continuing patient care. They are most commonly generated by voice dictation and are often of poor quality. The objective of this study was to compare discharge summaries created by voice dictation with those generated from a clinical database. METHODS: A randomized clinical trial was performed in which discharge summaries for patients discharged from a general internal medicine service at a tertiary care teaching hospital in Ottawa were created by voice dictation (151 patients) or from a database (142 patients). Patients had been admitted between September 1996 and June 1997. The trial was preceded by a baseline cohort study in which all summaries were created by dictation. For the database group, information on forms completed by housestaff was entered into a database and collated into a discharge summary. For the dictation group, housestaff dictated narrative letters. The proportion of patients for whom a summary was generated within 4 weeks of discharge was recorded. Physicians receiving the summary rated its quality, completeness, organization and timeliness on a 100-mm visual analogue scale. Housestaff preference was also determined. RESULTS: Patients in the database group and the dictation group were similar. A summary was much more likely to be generated within 4 weeks of discharge for patients in the database group than for those in the dictation group (113 [79.6%] v. 86 [57.0%]; p < 0.001). Summary quality was similar (mean rating 72.7 [standard deviation (SD) 19.3] v. 74.9 [SD 16.6]), as were assessments of completeness (73.4 [SD 19.8] v. 78.2 [SD 14.9]), organization (77.4 [SD 16.3] v. 79.3 [SD 17.2]) and timeliness (70.3 [SD 21.9] v. 66.2 [SD 25.6]). Many information items of interest were more likely to be included in the database-generated summaries. The database system created summaries faster and was preferred by housestaff. Dictated summaries in the baseline and
NASA Astrophysics Data System (ADS)
Das, Suman; Sadique Uz Zaman, J. K. M.; Ghosh, Ranjan
2016-06-01
In Advanced Encryption Standard (AES), the standard S-Box is conventionally generated by using a particular irreducible polynomial {11B} in GF(28) as the modulus and a particular additive constant polynomial {63} in GF(2), though it can be generated by many other polynomials. In this paper, it has been shown that it is possible to generate secured AES S-Boxes by using some other selected modulus and additive polynomials and also can be generated randomly, using a PRNG like BBS. A comparative study has been made on the randomness of corresponding AES ciphertexts generated, using these S-Boxes, by the NIST Test Suite coded for this paper. It has been found that besides using the standard one, other moduli and additive constants are also able to generate equally or better random ciphertexts; the same is true for random S-Boxes also. As these new types of S-Boxes are user-defined, hence unknown, they are able to prevent linear and differential cryptanalysis. Moreover, they act as additional key-inputs to AES, thus increasing the key-space.
Zhao, Youxuan; Li, Feilong; Cao, Peng; Liu, Yaolu; Zhang, Jianyu; Fu, Shaoyun; Zhang, Jun; Hu, Ning
2017-08-01
Since the identification of micro-cracks in engineering materials is very valuable in understanding the initial and slight changes in mechanical properties of materials under complex working environments, numerical simulations on the propagation of the low frequency S0 Lamb wave in thin plates with randomly distributed micro-cracks were performed to study the behavior of nonlinear Lamb waves. The results showed that while the influence of the randomly distributed micro-cracks on the phase velocity of the low frequency S0 fundamental waves could be neglected, significant ultrasonic nonlinear effects caused by the randomly distributed micro-cracks was discovered, which mainly presented as a second harmonic generation. By using a Monte Carlo simulation method, we found that the acoustic nonlinear parameter increased linearly with the micro-crack density and the size of micro-crack zone, and it was also related to the excitation frequency and friction coefficient of the micro-crack surfaces. In addition, it was found that the nonlinear effect of waves reflected by the micro-cracks was more noticeable than that of the transmitted waves. This study theoretically reveals that the low frequency S0 mode of Lamb waves can be used as the fundamental waves to quantitatively identify micro-cracks in thin plates. Copyright © 2017 Elsevier B.V. All rights reserved.
NASA Astrophysics Data System (ADS)
Matthews, J. O.; Hopcraft, K. I.; Jakeman, E.
2003-11-01
Some properties of classical population processes that comprise births, deaths and multiple immigrations are investigated. The rates at which the immigrants arrive can be tailored to produce a population whose steady state fluctuations are described by a pre-selected distribution. Attention is focused on the class of distributions with a discrete stable law, which have power-law tails and whose moments and autocorrelation function do not exist. The separate problem of monitoring and characterizing the fluctuations is studied, analysing the statistics of individuals that leave the population. The fluctuations in the size of the population are transferred to the times between emigrants that form an intermittent time series of events. The emigrants are counted with a detector of finite dynamic range and response time. This is modelled through clipping the time series or saturating it at an arbitrary but finite level, whereupon its moments and correlation properties become finite. Distributions for the time to the first counted event and for the time between events exhibit power-law regimes that are characteristic of the fluctuations in population size. The processes provide analytical models with which properties of complex discrete random phenomena can be explored, and in addition provide generic means by which random time series encompassing a wide range of intermittent and other discrete random behaviour may be generated.
Cassie state robustness of plasma generated randomly nano-rough surfaces
NASA Astrophysics Data System (ADS)
Di Mundo, Rosa; Bottiglione, Francesco; Carbone, Giuseppe
2014-10-01
Superhydrophobic surfaces are effective in practical applications provided they are “robust superhydrophobic”, i.e. able to retain the Cassie state, i.e. with water suspended onto the surface protrusions, even under severe conditions (high pressure, vibrations, high speed impact, etc.). We show that for randomly rough surfaces, given the Young angle, Cassie states are robust when a threshold value of the Wenzel roughness factor, rW, is exceeded. In particular, superhydrophobic nano-textured surfaces have been generated by self-masked plasma etching. In view of their random roughness, topography features, acquired by Atomic Force Microscopy, have been statistically analyzed in order to gain information on statistical parameters such as power spectral density, fractal dimension and Wenzel roughness factor (rW), which has been used to assess Cassie state robustness. Results indicate that randomly rough surfaces produced by plasma at high power or long treatment duration, which are also fractal self-affine, have a rW higher than the theoretical threshold, thus for them a robust superhydrophobicity is predicted. In agreement with this, under dynamic wetting conditionson these surfaces the most pronounced superhydrophobic character has been appreciated: they show the lowest contact angle hysteresis and result in the sharpest bouncing when hit by drops at high impact velocity.
Population clustering based on copy number variations detected from next generation sequencing data
Duan, Junbo; Zhang, Ji-Gang; Wan, Mingxi; Deng, Hong-Wen; Wang, Yu-Ping
2015-01-01
Copy number variations (CNVs) can be used as significant bio-markers and next generation sequencing (NGS) provides a high resolution detection of these CNVs. But how to extract features from CNVs and further apply them to genomic studies such as population clustering have become a big challenge. In this paper, we propose a novel method for population clustering based on CNVs from NGS. First, CNVs are extracted from each sample to form a feature matrix. Then, this feature matrix is decomposed into the source matrix and weight matrix with non-negative matrix factorization (NMF). The source matrix consists of common CNVs that are shared by all the samples from the same group, and the weight matrix indicates the corresponding level of CNVs from each sample. Therefore, using NMF of CNVs one can differentiate samples from different ethnic groups, i.e. population clustering. To validate the approach, we applied it to the analysis of both simulation data and two real data set from the 1000 Genomes Project. The results on simulation data demonstrate that the proposed method can recover the true common CNVs with high quality. The results on the first real data analysis show that the proposed method can cluster two family trio with different ancestries into two ethnic groups and the results on the second real data analysis show that the proposed method can be applied to the whole-genome with large sample size consisting of multiple groups. Both results demonstrate the potential of the proposed method for population clustering. PMID:25152046
NASA Astrophysics Data System (ADS)
Dasgupta, Sakyasingha; Nishikawa, Isao; Aihara, Kazuyuki; Toyoizumi, Taro
Source of cortical variability and its influence on signal processing remain an open question. We address the latter, by studying two types of balanced randomly connected networks of quadratic I-F neurons, with irregular spontaneous activity: (a) a deterministic network with strong connections generating noise by chaotic dynamics (b) a stochastic network with weak connections receiving noisy input. They are analytically tractable in the limit of large network-size and channel time-constant. Despite different sources of noise, spontaneous activity of these networks are identical unless majority of neurons are simultaneously recorded. However, the two networks show remarkably different sensitivity to external stimuli. In the former, input reverberates internally and can be read out over long time, but in the latter, inputs rapidly decay. This is further enhanced with activity-dependent plasticity at input synapses producing marked difference in decoding inputs from neural activity. We show, this leads to distinct performance of the two networks to integrate temporally separate signals from multiple sources, with the deterministic chaotic network activity serving as reservoir for Monte Carlo sampling to perform near optimal Bayesian integration, unlike its stochastic counterpart.
Numbers matter to informed patient choices: A randomized design across age and numeracy levels
Peters, Ellen; Hart, P. Sol; Tusler, Martin; Fraenkel, Liana
2013-01-01
Background How drug adverse events (AEs) are communicated in the United States may mislead consumers and result in low adherence. Requiring written information to include numeric AE-likelihood information might lessen these effects, but providing numbers may disadvantage less skilled populations. Objective To determine risk comprehension and willingness to use a medication when presented with numeric or non-numeric AE-likelihood information across age, numeracy, and cholesterol-lowering-drug-usage groups. Design In a cross-sectional internet survey (N=905; American Life Panel, 5/15/08–6/18/08), respondents were presented with a hypothetical prescription medication for high cholesterol. AE likelihoods were described using one of six formats (non-numeric: Consumer-Medication-Information (CMI)-like list, risk labels; numeric: percentage, frequency, risk-labels-plus-percentage, risk-labels-plus-frequency). Main outcome measures were risk comprehension (recoded to indicate presence/absence of risk overestimation and underestimation), willingness to use the medication (7-point scale; not likely=0, very likely=6), and main reason for willingness (chosen from eight predefined reasons). Results Individuals given non-numeric information were more likely to overestimate risk, less willing to take the medication, and gave different reasons than those provided numeric information across numeracy and age groups (e.g., among less numerate: 69% and 18% overestimated risks in non-numeric and numeric formats, respectively; among more numerate: these same proportions were 66% and 6%). Less numerate middle-aged and older adults, however, showed less influence of numeric format on willingness to take the medication. Limitations It is unclear whether differences are clinically meaningful although some differences are large. Conclusions Providing numeric AE-likelihood information (compared to non-numeric) is likely to increase risk comprehension across numeracy and age levels. Its
Zhang, Guo-Qiang; Tao, Shiqiang; Xing, Guangming; Mozes, Jeno; Zonjy, Bilal; Lhatoo, Samden D
2015-01-01
Background A unique study identifier serves as a key for linking research data about a study subject without revealing protected health information in the identifier. While sufficient for single-site and limited-scale studies, the use of common unique study identifiers has several drawbacks for large multicenter studies, where thousands of research participants may be recruited from multiple sites. An important property of study identifiers is error tolerance (or validatable), in that inadvertent editing mistakes during their transmission and use will most likely result in invalid study identifiers. Objective This paper introduces a novel method called "Randomized N-gram Hashing (NHash)," for generating unique study identifiers in a distributed and validatable fashion, in multicenter research. NHash has a unique set of properties: (1) it is a pseudonym serving the purpose of linking research data about a study participant for research purposes; (2) it can be generated automatically in a completely distributed fashion with virtually no risk for identifier collision; (3) it incorporates a set of cryptographic hash functions based on N-grams, with a combination of additional encryption techniques such as a shift cipher; (d) it is validatable (error tolerant) in the sense that inadvertent edit errors will mostly result in invalid identifiers. Methods NHash consists of 2 phases. First, an intermediate string using randomized N-gram hashing is generated. This string consists of a collection of N-gram hashes f 1, f 2, ..., f k. The input for each function f i has 3 components: a random number r, an integer n, and input data m. The result, f i(r, n, m), is an n-gram of m with a starting position s, which is computed as (r mod |m|), where |m| represents the length of m. The output for Step 1 is the concatenation of the sequence f 1(r 1, n 1, m 1), f 2(r 2, n 2, m 2), ..., f k(r k, n k, m k). In the second phase, the intermediate string generated in Phase 1 is encrypted
Akl, Elie A; Maroun, Nancy; Guyatt, Gordon; Oxman, Andrew D; Alonso-Coello, Pablo; Vist, Gunn E; Devereaux, P J; Montori, Victor M; Schünemann, Holger J
2007-12-01
To compare health care consumers' understanding, evaluations, and preferences for symbols vs. numbers and letters for the representation of strength of recommendations (SOR) and quality of evidence (QOE). Questionnaire study in a randomized controlled design in the setting of a community health education program. Eighty-four participants completed the questionnaire. For the presentation of the SOR, participants had better objective understanding of symbols than numbers (74% vs. 14%, P<0.001). They also scored symbols positively, and numbers negatively for ease of understanding (mean difference [md]=1.5, P=0.001), clearness and conciseness (md=1.5, P<0.001), and conveyance of the degree of uncertainty (md=0.7, P=0.092). About half (48%) preferred symbols over numbers. For the presentation of the QOE, objective understanding of symbols and letters was similar (91% vs. 95%, P=0.509). Participants scored both symbols and letters positively; the scores for symbols were however lower for ease of understanding (md=-0.7, P=0.019), clearness and conciseness (md=-0.6, P=0.051), and conveyance of the QOE (md=-0.4, P=0.24). Symbols were superior to numbers for the presentation of the SOR. Objective understanding was high for both symbols and letters for the presentation of the QOE, but letters conveyed the QOE better than symbols.
Education in Chronically Poor Rural Areas Lags across Generations. Issue Brief Number 24
ERIC Educational Resources Information Center
Ulrich, Jessica D.
2011-01-01
As part of the Community and Environment in Rural America (CERA) initiative, the Carsey Institute has been investigating broad trends between rural community types, including the education level of residents and their parents. Since 2007, Carsey researchers have conducted over 17,000 telephone surveys with randomly selected adult Americans from…