National Bureau of Economic Research

I didn't get a chance to hit the pumpkin patch this year, so I missed out on seeing any corn mazes. To make up for it, I decided to make some mazes of my own! Being a programmer, I over-engineered it and built a random maze generator!

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Two commonly encountered bottlenecks in the structure determination of a protein by X-ray crystallography are screening for conditions that give high-quality crystals and, in the case of novel structures, finding derivatization conditions for experimental phasing. In this study, the phasing molecule 5-amino-2,4,6-triiodoisophthalic acid (I3C) was added to a random microseed matrix screen to generate high-quality crystals derivatized with I3C in a single optimization experiment. I3C, often referred to as the magic triangle, contains an aromatic ring scaffold with three bound I atoms. This approach was applied to efficiently phase the structures of hen egg-white lysozyme and the N-terminal domain of the Orf11 protein from Staphylococcus phage P68 (Orf11 NTD) using SAD phasing. The structure of Orf11 NTD suggests that it may play a role as a virion-associated lysin or endolysin.

One study that looked at kids' sleep and behavior patterns might have missed the bigger picture. Another study looks at academic performance.

A whole new kingdom will need to be created to classify Hemimastix kukwesjijk, the organisms found in a random dirt sample.

Following in the footsteps of Fibonacci and the Mandelbrot Set, a computer program creates beautiful structures of chaos.

Send love into the world with a little bit of creativity and paint.

Automotive Review Co. has conducted a randomized and unedited survey which asked over 800 randomly selected customers about the experience they have had with the Supreme Performance Chip 4.0 as well as the company Great Lakes Auto

Margaret Parker, MD, MCCM, speaks Mark Duffett, PhD, about the article, High-Quality Randomized Controlled Trials in Pediatric Critical Care: A Survey of Barriers and Facilitators, published in the May 2017 issue of Pediatric Critical Care Medicine.

A CSS3 Random Heroes game, animated sprites using no images.

Isobar’s Rob Larsen suggests that there is often a need to build CSS selectors dynamically when building applications. ”This is typically some existing pattern paired with a loop counter or something pulled from a data attribute,” he writes on his blog. His choice is to create a variable called ”selector” and ”to craft the selector Read the rest...

A natural problem in the context of the coupon collector's problem is the behavior of the maximum of independent geometrically distributed random variables (with distinct parameters). This question has been addressed by Brennan et al. (British J. of Math. & CS. 8 (2015), 330-336). Here we provide explicit asymptotic expressions for the moments of that maximum, as well as of the maximum of exponential random variables with corresponding parameters. We also deal with the probability of each of the variables being the maximal one.

The calculations lead to expressions involving Hurwitz's zeta function at certain special points. We find here explicitly the values of the function at these points. Also, the distribution function of the maximum we deal with is closely related to the generating function of the partition function. Thus, our results (and proofs) rely on classical results pertaining to the partition function.

We apply the paracontrolled calculus to study the asymptotic behavior of a certain quasilinear PDE with smeared mild noise, which originally appears as the space-time scaling limit of a particle system in random environment on one dimensional discrete lattice. We establish the convergence result and show a local in time well-posedness of the limit stochastic PDE with spatial white noise. It turns out that our limit stochastic PDE does not require any renormalization. We also show a comparison theorem for the limit equation.

We show that a random puncturing of a code with good distance is list recoverable beyond the Johnson bound. In particular, this implies that there are Reed-Solomon codes that are list recoverable beyond the Johnson bound. It was previously known that there are Reed-Solomon codes that do not have this property. As an immediate corollary to our main theorem, we obtain better degree bounds on unbalanced expanders that come from Reed-Solomon codes.

We perform an effectivization of classical results concerning universal coding and prediction for stationary ergodic processes over an arbitrary finite alphabet. That is, we lift the well-known almost sure statements to statements about Martin-L"of random sequences. Most of this work is quite mechanical but, by the way, we complete a result of Ryabko from 2008 by showing that each universal probability measure in the sense of universal coding induces a universal predictor in the prequential sense. Surprisingly, the effectivization of this implication holds true provided the universal measure does not ascribe too low conditional probabilities to individual symbols. As an example, we show that the Prediction by Partial Matching (PPM) measure satisfies this requirement. In the almost sure setting, the requirement is superfluous.

We utilize recent results on the exact block error probability of Gaussian random codes in additive white Gaussian noise to analyze Gaussian random coding for massive multiple-access at finite message length. Soft iterative interference cancellation is found to closely approach the performance bounds recently found in [1]. The existence of two fundamentally different regimes in the trade-off between power and bandwidth efficiency reported in [2] is related to much older results in [3] on power optimization by linear programming. Furthermore, we tighten the achievability bounds of [1] in the low power regime and show that orthogonal constellations are very close to the theoretical limits for message lengths around 100 and above.

This paper investigates the convergence of the randomized Kaczmarz algorithm for the problem of phase retrieval of complex-valued objects. While this algorithm has been studied for the real-valued case}, its generalization to the complex-valued case is nontrivial and has been left as a conjecture. This paper establishes the connection between the convergence of the algorithm and the convexity of an objective function. Based on the connection, it demonstrates that when the sensing vectors are sampled uniformly from a unit sphere and the number of sensing vectors $m$ satisfies $m>O(nlog n)$ as $n, m ightarrowinfty$, then this algorithm with a good initialization achieves linear convergence to the solution with high probability.

Randomized Numerical Linear Algebra (RandNLA) uses randomness to develop improved algorithms for matrix problems that arise in scientific computing, data science, machine learning, etc. Determinantal Point Processes (DPPs), a seemingly unrelated topic in pure and applied mathematics, is a class of stochastic point processes with probability distribution characterized by sub-determinants of a kernel matrix. Recent work has uncovered deep and fruitful connections between DPPs and RandNLA which lead to new guarantees and improved algorithms that are of interest to both areas. We provide an overview of this exciting new line of research, including brief introductions to RandNLA and DPPs, as well as applications of DPPs to classical linear algebra tasks such as least squares regression, low-rank approximation and the Nystr"om method. For example, random sampling with a DPP leads to new kinds of unbiased estimators for least squares, enabling more refined statistical and inferential understanding of these algorithms; a DPP is, in some sense, an optimal randomized algorithm for the Nystr"om method; and a RandNLA technique called leverage score sampling can be derived as the marginal distribution of a DPP. We also discuss recent algorithmic developments, illustrating that, while not quite as efficient as standard RandNLA techniques, DPP-based algorithms are only moderately more expensive.

A perpendicular spin-transfer torque magnetic random access memory (STTMRAM) element includes a fixed layer having a magnetization that is substantially fixed in one direction and a barrier layer formed on top of the fixed layer and a free layer. The free layer has a number of alternating laminates, each laminate being made of a magnetic layer and an insulating layer. The magnetic layer is switchable and formed on top of the barrier layer. The free layer is capable of switching its magnetization to a parallel or an anti-parallel state relative to the magnetization of the fixed layer during a write operation when bidirectional electric current is applied across the STTMRAM element. Magnetic layers of the laminates are ferromagnetically coupled to switch together as a single domain during the write operation and the magnetization of the fixed and free layers and the magnetic layers of the laminates have perpendicular anisotropy.

Methods using a sequence of externally generated magnetic fields to initialize the magnetization directions of each of the layers in perpendicular MTJ MRAM elements for data and reference bits when the required magnetization directions are anti-parallel are described. The coercivity of the fixed pinned and reference layers can be made unequal so that one of them can be switched by a magnetic field that will reliably leave the other one unswitched. Embodiments of the invention utilize the different effective coercivity fields of the pinned, reference and free layers to selectively switch the magnetization directions using a sequence of magnetic fields of decreasing strength. Optionally the chip or wafer can be heated to reduce the required field magnitude. It is possible that the first magnetic field in the sequence can be applied during an annealing step in the MRAM manufacture process.

A circuit arrangement and method couple a hardware-based pseudorandom number generator (PRNG) to an execution unit in such a manner that pseudorandom numbers generated by the PRNG may be selectively output to the execution unit for use as an operand during the execution of instructions by the execution unit. A PRNG may be coupled to an input of an operand multiplexer that outputs to an operand input of an execution unit so that operands provided by instructions supplied to the execution unit are selectively overridden with pseudorandom numbers generated by the PRNG. Furthermore, overridden operands provided by instructions supplied to the execution unit may be used as seed values for the PRNG.

In accordance with one or more aspects, an initial output string is generated by a random number generator. The initial output string is sent to a random number service, and an indication of failure is received from the random number service if the initial output string is the same as a previous initial output string received by the random number service. Operation of the device is ceased in response to the indication of failure. Additionally, entropy estimates for hash values of an entropy source can be generated by an entropy estimation service based on hash values of various entropy source values received by the entropy estimation service. The hash values can be incorporated into an entropy pool of the device, and the entropy estimate of the pool being updated based on the estimated entropy of the entropy source.

A random number generation method and apparatus using a low-power microprocessor is provided. In the random number generation method, a low-power microprocessor determines whether external power is supplied to a random number generator. The low-power microprocessor updates an internal state of the random number generator based on a first scheme if it is determined that the external power is supplied to the random number generator. The low-power microprocessor updates the internal state of the random number generator based on a second scheme different from the first scheme if it is determined that the external power is not supplied to the random number generator.

The disclosure is related systems and methods for using operation durations of a data storage medium to generate random numbers. In one embodiment, a device may comprise a random number generator circuit configured to store a value representing a duration of an operation on the data storage medium, and generate a random number based on the value. Another embodiment may be a method comprising recording durations of access operations to a data storage medium, and generating a random number based on the durations.

A method for generating multi-level (or multi-bit) pseudo-random sequences is disclosed. This embodiment relates to communication systems, and more particularly to generating multi-level pseudo random symbol sequence. Present day systems do not employ effective mechanisms for generation of multi level PRBS in order to increase the data communication rates. Further, these systems do not cover all the possible transitions for the outputs of the system. The proposed system employs mechanisms in order to generate PRBS signals for producing multi levels signals to the electronic components. The mechanism employs alternate bit tapping techniques. In the alternate bit tapping technique, bits are tapped alternatively to determine the current state and the next state of the system. In addition, the mechanism also covers all the possible states of the output vector with transitions between the output states. This ensures that high data rates are obtained for a given bandwidth of operation.

A data processing apparatus is provided for producing a randomized value. A cell in the data processing apparatus comprises a dielectric oxide layer and stress voltage circuitry is configured to apply a stress voltage across the dielectric oxide layer of the cell to cause an oxide breakdown process to occur. Oxide breakdown detection circuitry is configured to determine a current extent of the oxide breakdown process by measuring a response of the dielectric oxide layer to the stress voltage and randomized value determination circuitry is configured to determine a randomized value in dependence on the current extent of the oxide breakdown process.

A strap comprising a propylene and 1-hexene copolymer containing from 0.3 wt % to less than 5 wt % of 1-hexene derived units said copolymer having a melt flow rate (MFR) determined according to ISO method 1133 (230° C., 2.16 kg ranging from 0.3 to less than 11 g/10 min.

A secret stream of bits begins by receiving a public random stream contained in a wireless communication signal at a transmit/receive unit. The public random stream is sampled and specific bits are extracted according to a shared common secret. These extracted bits are used to create a longer secret stream. The shared common secret may be generated using JRNSO techniques, or provided to the transmit/receive units prior to the communication session. Alternatively, one of the transmit/receive unit is assumed to be more powerful than any potential eavesdropper. In this situation, the powerful transmit/receive unit may broadcast and store a public random stream. The weaker transmit/receive unit selects select random bits of the broadcast for creating a key. The weaker transmit/receive unit sends the powerful transmit/receive unit the selected bit numbers, and powerful transmit/receive unit uses the random numbers to produce the key created by the weaker transmit/receive unit.

An apparatus and method for converting a random binary sequence into a random integer is provided. The present invention converts a random binary sequence into a random integer, and determines whether the corresponding random integer falls within a preset integer interval. Further, if it is determined that the random integer generated from the random binary sequence does not fall within the preset integer interval, the present invention repeatedly updates a random binary sequence until a random integer falling within the corresponding integer interval is obtained, thus outputting uniformly distributed random integers which fall within the preset integer interval.

A self-feedback random generator comprises a digital-to-analog converter, a digital oscillator, a frequency-modulating unit and a first D-type flip-flop. The digital-to-analog converter receives a digital random-code signal and the digital random-code signal is converted to corresponding analog random signal. The frequency-modulating unit modulates frequency of first digital oscillating signal so as to increase random of frequency of first digital oscillating signal according to voltage value of the analog random signal, and accordingly outputs a second digital oscillating signal. The first D-type flip-flop receives the second digital oscillating signal and a clock signal, and reads the second digital oscillating signal through utilizing the clock signal so as to outputs the digital random-code signal, wherein frequency of the clock signal is smaller than frequency of the first digital oscillating signal, and random of frequency of the second digital oscillating signal corresponds to random of the digital random-code signal.

Embodiments generally relate to optoelectronic devices and more specifically, to textured layers in optoelectronic devices. In one embodiment, a method for providing a textured layer in an optoelectronic device includes depositing a first layer of a first material and depositing an island layer of a second material on the first layer. Depositing the island layer includes forming one or more islands of the second material to provide at least one textured surface of the island layer, where the textured surface is operative to cause scattering of light.

Apparatuses and methods for moving playing cards from a first group of cards into plural hands of cards, wherein each of the hands contains a random arrangement of cards. The apparatus may comprise a card receiver for receiving the first group of cards, a single stack of card-receiving compartments generally adjacent to the card receiver, the stack generally vertically movable, an elevator for moving the stack, a card-moving mechanism between the card receiver and the stack, and a microprocessor that controls the card-moving mechanism and the elevator so that an individual card is moved into an identified compartment. The number of compartments receiving cards and the number of cards moved to each compartment may be selected. Apparatuses for feeding cards may comprise a surface for supporting a stack of cards, a feed roller with a frictional outer surface, a drive mechanism for causing rotation of the feed roller, a pair of speed-up rollers to advance the cards out of the feed roller, and a clutch mechanism for disengaging the feed roller from the drive mechanism as the card comes into contact with the speed-up rollers.

An SRAM includes an SRAM array comprising a plurality of SRAM cells arranged in a matrix. Each of the SRAM cells includes six vertical field effect transistors. The SRAM array includes a plurality of groups of conductive regions extending in the column direction. Each of the plurality of groups of conductive regions includes a first to a fourth conductive region arranged in this order in the row direction, and the first to fourth conductive regions are separated by insulating regions from each other. The first, second and third conductive regions are coupled to sources of first conductive type VFETs, and the fourth conductive region is coupled to sources of second conductive type VFETs. The plurality of groups are arranged in the row direction such that the fourth conductive region of one group of conductive regions is adjacent to the first conductive region of adjacent one group of conductive regions.

A bit line architecture for dual-port static random-access memory (DP SRAM) is provided. An array of memory cells is arranged in rows and columns, and comprises a first subarray and a second subarray. A first pair of complementary bit lines (CBLs) extends along a column, from a first side of the array, and terminates between the first and second subarrays. A second pair of CBLs extends from the first side of the array, along the column, to a second side of the array. The CBLs of the second pair of CBLs have stepped profiles between the first and second subarrays. A third pair of CBLs and a fourth pair of CBLs extend along the column. The first and third pairs of CBLs electrically couple to memory cells in the first subarray, and the second and fourth pairs of CBLs electrically couple to memory cells in the second subarray.

A magnetoresistive random access memory (MRAM) structure includes a bottom electrode structure. A magnetic tunnel junction (MTJ) element is over the bottom electrode structure. The MTJ element includes an anti-ferromagnetic material layer. A ferromagnetic pinned layer is over the anti-ferromagnetic material layer. A tunneling layer is over the ferromagnetic pinned layer. A ferromagnetic free layer is over the tunneling layer. The ferromagnetic free layer has a first portion and a demagnetized second portion. The MRAM also includes a top electrode structure over the first portion.

A method for providing a randomized card engine for use in wagering card games which thwarts advantage play methods in live or electronic gaming formats, which includes the steps of shuffling, or simulating the shuffling of, a plurality of standard decks of physical playing cards to form a set of playing cards in a randomly-ordered condition, dividing the set of randomly-ordered playing cards into a plurality of subsets, and providing each subset of the plurality of subsets for independent use in a respective card wagering game.

A method of making a MRAM device includes forming a magnetic tunnel junction on an electrode, the magnetic tunnel junction comprising a reference layer positioned in contact with the electrode, a tunnel barrier layer arranged on the reference layer, and a free layer arranged on the tunnel barrier layer; and depositing an encapsulating layer on and along sidewalls of the magnetic tunnel junction; wherein the exposing of the magnetic tunnel junction to hydrogen plasma is performed at a temperature from about 150 to about 250° C. An MRAM device including an encapsulating layer comprising either silicon nitride or aluminum oxide is also provided.

During the WCBE spring fund drive the staff was so inspired by your responses that we promised to each do five random acts of kindness in your honor. Coming up with ideas wasn’t hard, and putting them into action was even easier. In fact, I realized there were different categories of RAK. Some of the things I did in your name were not-so-random; every week when I do my grocery shopping now, I spend $5-10 on food for the free Little Pantry in my neighborhood, to provide a snack or an extra meal for someone who needs it. Some were practical, like taking cat litter and a dozen cans of prescription food to the folks at Cat Welfare. Some were more… whimsical. I used scraps of old sweaters to make a dozen or so little monsters – then scattered them around the children’s sections of two different libraries. Some of the best RAKs, the ones that make people smile, are small, spontaneous gestures. In the course of this challenge to myself, I realized how many opportunities there are in a day for

A few of us had the opportunity to visit with a lovely woman who may be WCBE's longest-living listener. Anne Smith has lived in Columbus since 1957, a year after 90.5 began broadcasting. Anne loves to listen to 90.5 with her son Roger and especially enjoys the music. Caitlin Farkas, Maggie Brennan, and Mike Foley visited with Anne during her special birthday celebration this past weekend. We arrived just in time to join her family and friends in singing " Happy Birthday." Can you believe this beautiful woman is 102 years old? Anne's smile and kindness truly inspired us. We're so grateful to have shared a small part of her special day. WCBE staff have been dedicated to bringing the Central Ohio community Random Acts of Kindness since our spring fundraiser. Be sure to spread the kindness and let us know which random act of kindness you performed today by sending us an email!

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