Digit Strings Research Articles

Impaired visual processing of letter and digit strings in adult dyslexic readers

The slow word reading of developmental dyslexics may stem from a string processing impairment which in turn reflects visual attentional deficits. We indeed found substantially enhanced recognition time thresholds in the dyslexic adult readers. However, their position profiles were hard to reconcile with any of the discussed visual attentional deficit hypotheses and with the prediction that dyslexic readers suffer from an absent string processing system as they exhibited similar M-shaped position profiles for digit and letter strings as the normal reading controls.

Numbers and space: a cognitive illusion?

This study investigated the relationships between numerical and spatial representations by means of a bisection task, exploring the view that the core representation of number meaning is spatially organized as a mental number line. In Experiment nos. 1 (bisection of digit strings) and 2 (bisection of flanked lines) spatial biases towards the larger digit were found to be related only to processing of relative magnitude. Experiment nos. 3 (bisection of an unfilled space) and 4 (bisection of flanked lines/unfilled spaces) aimed at disclosing perceptual, attentional, and numerical constraints on the bias induced by the position of the larger digit. This effect is interpreted in terms of a cognitive illusion of length, whereby a spatial bias compensates for the numerical disparity. This seems to operate in a categorical fashion ("small/large"), and to be congruent with the assumption that relatively large numbers are associated with the right side of a mental representational space.

Executive control of working memory in schizophrenia

There is considerable evidence that working memory impairment is a common feature of schizophrenia. The present study assessed working memory and executive function in 54 participants with schizophrenia, and a group of 54 normal controls matched to the patients on age, gender and estimated premorbid IQ, using traditional and newer measures of executive function and two dual tasks—Telephone Search with Counting and the Memory Span and Tracking Task. Results indicated that participants with schizophrenia were significantly impaired on all standardised measures of executive function with the exception of a composite measure of the Trail Making Test. Results for the dual task measures demonstrated that while the participants with schizophrenia were unimpaired on immediate digit span recall over a 2-min period, they recalled fewer digit strings and performed more poorly on a tracking task (box-crossing task) compared with controls. In addition, participants with schizophrenia performed more poorly on the tracking task when they were required to simultaneously recall digits strings than when they performed this task alone. Contrary to expectation, results of the telephone search task under dual conditions were not significantly different between groups. These results may reflect the insufficient complexity of the tone-counting task as an interference task. Overall, the present study showed that participants with schizophrenia appear to have a restricted impairment of their working memory system that is evident in tasks in which the visuospatial sketchpad slave system requires central executive control.

Adaptive genetic algorithm for lot-sizing problem with self-adjustment operation rate

This paper presents a new adaptive genetic algorithm (GA) to escape local optimum solutions of the traditional lot-sizing rules. In this GA, the timing of replenishment is encoded as a string of binary digits (a chromosome). Each gene in that chromosome stands for a period. Standard GA operators are used to generate new populations. These populations are evaluated by a fitness function using the replenishment scheme of solution based on the total cost. Through this evaluation, the rates of GA operators for the next generation are automatically adjusted based on the rate of survivor offsprings, which are generated by corresponding operators. The oriented search procedure using these self-adjustment rates of operator schemes can give faster and better solutions. Some experimental results confirm the theoretical judgment.

Crack Identification in Plates Using Genetic Algorithm

When a crack exists in a structural member, it leads to changes in natural frequencies. Therefore, cracks in structures can be detected by measuring the vibrations in the natural frequencies of appropriate vibration modes. In this paper a crack identification method for plates is presented using both a genetic algorithm (GA) and FEM. The FEM program is developed to calculate the natural frequencies of the cracked plates based on the BFM (Bogner, Fox and Schmidt) plate model since the accuracy of the forward solver is important. In the study, two types of cracks, i.e., internal and edge crack are considered. To identify the crack location and the depth from frequency measurements, the width and the position of the crack in a plate are coded into fixed-length binary digit string. By using GA, the square sum of residuals between the measured data and the dynamic response is minimized in the identification process and thus the crack is identified. To avoid a large number of calculation cost, Response Surface Method (RSM) is also adopted in the minimizing process. The combination of GA and RSM made the identification more effective ad robust. The availability of the proposed method is confirmed by -results of numerical simulation.

Stringed instrument with embedded DSP modeling

Disclosed is a stringed instrument (100) with embedded digital signal processing (DSP) modeling capabilities. The stringed instrument (100) has a body (102) and a plurality of strings (106) and each of the plurality of strings (106) is respectively coupled to a pickup of a polyphonic pickup (110). The polyphonic pickup (110) is used to detect a vibration signal for each string (106). An A/D converter converts the detected vibration signal of a string into a digital string vibration signal. Further, a digital signal processor (120) is located within the body of the stringed instrument to process the digital string vibration signal. Particularly, the digital signal processor (120) is used to process the digital string vibration signal such that the corresponding string tone of one of a plurality of selectable stringed instruments may be emulated. The emulated digital tone signal is then converted to analog form to create an emulated analog tone signal for output to an amplification device.

Why are non-native (L2) utterances longer than native-produced utterances?

Research has repeatedly shown that utterances produced by non-native speakers are longer than those of native speakers, even when produced as rapidly as possible. The non-native speaking rate effect is known to be greater for late than early L2 learners, but may disappear for late learners when very short-duration L2 utterances are examined. This study examined the duration of English utterances produced by native English (NE) speakers and late native Spanish (NS) learners of English (n=20 each). For normal-rate utterances, durations were significantly longer for the NS than NE group for syntactically complex sentences (e.g., The boy saw that Gary forgot a box of pencils) but not simple sentences (Gary forgot a box of pencils) or noun phrases (a box of pencils). However, the NS-NE difference reached significance for all three utterance types at a fast rate. In Experiment 2, the NS group took longer than the NE group to produce the digit string 1 2 3 4 5 6 7 as rapidly as possible. Taken together, the results suggest that differences in both the articulation of L2 speech sounds and higher-order planning (including the formulation of syntactic representations) contribute to the nonnative speaking rate effect. [Work supported by NIH.]

Final Digit Strings of Cubes

Let s be the string of decimal digits 31415926535 . . . 5275045519 formed by the first billion digits of zz. You have probably wondered idly whether there is an integer n such that n3 ends in s. Or, to take another example, let s be formed by concatenating the decimal digits of 9993, 9983, . . ., 23, 13, and ask the same question. The fourth annual North Central Section/MAA Team Contest [1] of November 2000, contained the following problem: Is there an integer n such that n3, in decimal form, ends in 2000 ones? The answer to all three of the above questions is affirmative. Indeed, if s is any string of decimal digits ending in 1, 3, 7, or 9, there is an integer n such that n3 ends in s, as we'll see in the next section. What about other final digit strings? If the last digit of s is anything other than 1, 3, 7, or 9, there may or may not be a cube ending in s. The precise conditions under which there is such a cube are rather interesting, and are given in three subsequent sections. From the material there you can conclude that there are cubes ending VOL. 77, NO. 2, APRIL 2004 149

Why is it difficult to see in the fog? How stimulus contrast affects visual perception and visual memory.

Processing visually degraded stimuli is a common experience. We struggle to find house keys on dim front porches, to decipher slides projected in overly bright seminar rooms, and to read 10th-generation photocopies. In this research, we focus specifically on stimuli that are degraded via reduction of stimulus contrast and address two questions. First, why is it difficult to process low-contrast, as compared with high-contrast, stimuli? Second, is the effect of contrast fundamental in that its effect is independent of the stimulus being processed and the reason for processing the stimulus? We formally address and answer these questions within the context of a series of nested theories, each providing a successively stronger definition of what it means for contrast to affect perception and memory. To evaluate the theories, we carried out six experiments. Experiments 1 and 2 involved simple stimuli (randomly generated forms and digit strings), whereas Experiments 3-6 involved naturalistic pictures (faces, houses, and cityscapes). The stimuli were presented at two contrast levels and at varying exposure durations. The data from all the experiments allow the conclusion that some function of stimulus contrast combines multiplicatively with stimulus duration at a stage prior to that at which the nature of the stimulus and the reason for processing it are determined, and it is the result of this multiplicative combination that determines eventual memory performance. We describe a stronger version of this theory--the sensory response, information acquisition theory--which has at its core, the strong Bloch's-law-like assumption of a fundamental visual system response that is proportional to the product of stimulus contrast and stimulus duration. This theory was, as it has been in the past, highly successful in accounting for memory for simple stimuli shown at short (i.e., shorter than an eye fixation) durations. However, it was less successful in accounting for data from short-duration naturalistic pictures and was entirely unsuccessful in accounting for data from naturalistic pictures shown at longer durations. We discuss (1) processing differences between short- and long-duration stimuli, (2) processing differences between simple stimuli, such as digits, and complex stimuli, such as pictures, (3) processing differences between biluminant stimuli (such as line drawings with only two luminance levels) and multiluminant stimuli (such as grayscale pictures with multiple luminance levels), and (4) Bloch's law and a proposed generalization of the concept of metamers.

An Innovative Prosody Modeling Method for Chinese Speech Recognition

This paper presents an innovative method for prosody modeling in Chinese speech recognition. Our method first evaluated the reliability of the prosodic information by which the recognition system dynamically tunes the balance between the spectral scores and prosodic scores. The basic idea of this method is to use prosodic knowledge based on its reliability. The higher the reliability, the more the prosodic information contributes to recognition. Thus, this method will not introduce extra errors but will incorporate more knowledge into the recognition system. Experimental results showed that this method reduced the relative word error rate by as much as 52.9% and 46.0% for Mandarin and Cantonese digit string recognition tasks, respectively. When incorporating tone information into Cantonese Large Vocabulary Continuous Speech Recognition (LVCSR) via the proposed method, a 20.16% relative character error rate reduction was obtained.

A stochastic model of cytotoxic T cell responses

We have constructed a stochastic stage-structured model of the cytotoxic T lymphocyte (CTL) response to antigen and the maintenance of immunological memory. The model follows the dynamics of a viral infection and the stimulation, proliferation, and differentiation of naı̈ve CD8 + T cells into effector CTL, which can eliminate virally infected cells. The model is capable of following the dynamics of multiple T cell clones, each with a T cell receptor represented by a digit string. MHC–viral peptide complexes are also represented by strings and a string match rule is used to compute the affinity of a T cell receptor for a viral epitope. The avidities of interactions are also computed by taking into consideration the density of MHC–viral peptides on the surface of an infected cell. Lastly, the model allows the probability of T cell stimulation to depend on avidity but also incorporates the notion of an antigen-independent programmed proliferative response. We compare the model to experimental data on the cytotoxic T cell response to lymphocytic choriomeningitis virus infections.

On the Hausdorff dimension of generalized Besicovitch-Eggleston sets of d-tuples of numbers

We give a systematic and detailed account of the Hausdorff dimensions of sets of d-tuples of numbers defined in terms of the asymptotic behaviour of the frequencies of strings of digits in their N-adic expansion.

固有振動数変化に基づくき裂を有する平板のき裂同定 : 面内振動の場合(オーガナイズドセッション,材料強度と構造設計)

When a crack exists in a structural member, it leads to changes in natural frequencies. Therefore, cracks in structures can be detected by measuring the natural frequencies. In this paper a method for identification of a crack in a in-plane vibration plate is presented using both a genetic algorithm (GA) and FEM. The FEM program is developed to calculate the natural frequencies of the cracked plates based on the 8-node quadrilateral model. In the analysis, two types of cracks, i.e., internal and edge crack are considered. To identify the crack location and the size from frequency measurements, the size and the position of the crack in a plate are coded into fixed-length binary digit string. By using GA, the square sum of residuals between the measured data and the dynamic response is minimized in the identification process and thus the crack is identified. The availability of the proposed method is confirmed by results of numerical simulation.

Inverse relation between postural variability and difficulty of a concurrent short-term memory task

We measured postural stability while participants simply stood or stood while performing a digit rehearsal task of varying levels of difficulty in order to examine the effects on postural control of concurrent short-term memory demands. The rehearsal task manipulation avoided factors that contaminate postural sway measurements, such as vocal articulation or visual fixation during posture data collection. When participants performed the more difficult digit tasks (longer digit strings), postural sway was reduced relative to when performing an easy version of the task (few digits). The results identified a complex relation between postural control and cognitive or attentional demands.

A Methodology for Feature Selection Using Multiobjective Genetic Algorithms for Handwritten Digit String Recognition

In this paper a methodology for feature selection for the handwritten digit string recognition is proposed. Its novelty lies in the use of a multiobjective genetic algorithm where sensitivity analysis and neural network are employed to allow the use of a representative database to evaluate fitness and the use of a validation database to identify the subsets of selected features that provide a good generalization. Some advantages of this approach include the ability to accommodate multiple criteria such as number of features and accuracy of the classifier, as well as the capacity to deal with huge databases in order to adequately represent the pattern recognition problem. Comprehensive experiments on the NIST SD19 demonstrate the feasibility of the proposed methodology.

Algorithmic randomness in empirical data

According to a traditional view, scientific laws and theories constitute algorithmic compressions of empirical data sets collected from observations and measurements. This article defends the thesis that, to the contrary, empirical data sets are algorithmically incompressible. The reason is that individual data points are determined partly by perturbations, or causal factors that cannot be reduced to any pattern. If empirical data sets are incompressible, then they exhibit maximal algorithmic complexity, maximal entropy and zero redundancy. They are therefore maximally efficient carriers of information about the world. Since, on algorithmic information theory, a string is algorithmically random just if it is incompressible, the thesis entails that empirical data sets consist of algorithmically random strings of digits. Rather than constituting compressions of empirical data, scientific laws and theories pick out patterns that data sets exhibit with a certain noise.

The influence of string length and repetition on chunking of digit strings.

This study examined the effects of string length and repetitions on number processing with a data entry task. Participants read and entered strings of between three and eight digits and then typed them on the keypad of a computer. Chunking effects were found for all string lengths, with chunk sizes of as small as two digits. Chunk boundary placement varied depending on the length of a digit string, and chunking was avoided at positions between digit repetitions, even when those positions were otherwise common chunk boundaries. Digit repetitions significantly reduced the study time required to process a string prior to its entry. These results are interpreted as showing that flexible chunking strategies and the presence of repetitions are used to facilitate number processing.

Segmentation and recognition of handwritten dates: an HMM-MLP hybrid approach

This paper presents an HMM-MLP hybrid system for segmenting and recognizing complex date images written on Brazilian bank checks. Through the recognition process, the system makes use of an HMM-based approach to segment a date image into subfields. Then the three obligatory date subfields (day, month, and year) are processed. A neural approach has been adopted to decipher strings of digits (day and year) and a Markovian strategy to recognize and verify words (month). The final decision module makes an accept/reject decision. We also introduce the concept of metaclasses of digits to reduce the lexicon size of the day and year and improve the precision of their segmentation and recognition. Experiments show interesting results on date recognition.

Effective Complexity as a Measure of Information Content

Murray Gell-Mann has proposed the concept of effective complexity as a measure of information content. The effective complexity of a string of digits is defined as the algorithmic complexity of the regular component of the string. This paper argues that the effective complexity of a given string is not uniquely determined. The effective complexity of a string admitting a physical interpretation, such as an empirical data set, depends on the cognitive and practical interests of investigators. The effective complexity of a string as a purely formal construct, lacking a physical interpretation, is either close to zero, or equal to the string's algorithmic complexity, or arbitrary, depending on the auxiliary criterion chosen to pick out the regular component of the string. Because of this flaw, the concept of effective complexity is unsuitable as a measure of information content.

음절수와 모음 열을 이용한 한국어 연결 숫자 음성인식

본 논문에서는 음절수와 모음 열 정보를 이용한 한국어 연속 숫자 인식을 제안하였다. 제안한 연속 숫자 인식기는 첫 단계로 발성된 연속 숫자 음성에서 음절수와 구간을 추출하고, 두 번째 단계로 모음 열을 인식한다. 이와 같이 인식된 모음 열 정보를 이용하여 인식 후보를 줄이게 된다. 인식후보 모델은 조음효과에 효과적으로 대처할 수 있는 CV(Consonant Vowel), VCCV, VC단위 HMM(Hidden Markov Model)을 사용하여 연속 숫자 음성인식기를 구성하였다. 실험결과 제안된 방법이 조음효과를 효과적으로 대처하고 연결 숫자 인식에 유효함을 확인하였다. In this paper, we present a new Korean connected digit recognition based on vowel string and number of syllables. There are two steps to reduce digit candidates. The first one is to determine the number and interval of digit. Once the number and interval of digit are determined, the second is to recognize the vowel string in the digit string. The digit candidates according to vowel string are recognized based on CV (consonant vowel), VCCV and VC unit HMM. The proposed method can cope effectively with the coarticulation effects and recognize the connected digit speech very well.