Letter Pairs Research Articles

The Optimization of Numerical Algorithm Parameters with a Genetic Algorithm to Animate Letters of the Sign Alphabet

At present, the development of animation-based works for human–computer interaction applications has increased. To generate animations, actions are pre-recorded and animation flows are configured. In this research, from two images of letters of the sign language alphabet, intermediate frames were generated using a numerical traced algorithm based on homotopy. The parameters of a homotopy curve were optimized with a genetic algorithm to generate intermediate frames. In the experiments performed, sequences where a person executes pairs of letters in sign language were recorded and animations of the same pairs of letters were generated with the proposed method. Subsequently, the similarity of the real sequences to the animations was measured using Dynamic Time Wrapping. The results obtained show that the images obtained are consistent with their execution by a person. Animation files between sign pairs were created from sign images, with each file weighing an average of 18.3 KB. By having sequences between pairs of letters it is possible to animate words and sentences. The animations generated by this homotopy-based animation method optimized with a genetic algorithm can be used in various deaf interaction applications to provide assistance. From several pairs of letters a file base was generated using the animations between pairs of letters; with these files you can create animations of words and sentences.

Generalizing Körner’s graph entropy to graphons

Körner introduced the notion of graph entropy in 1973 as the minimal code rate of a natural coding problem where not all pairs of letters can be distinguished in the alphabet. Later it turned out that it can be expressed as the solution of a minimization problem over the so-called vertex-packing polytope.In this paper we generalize this notion to graphons. We show that the analogous minimization problem provides an upper bound for graphon entropy. We also give a lower bound in the shape of a maximization problem. The main result of the paper is that for most graphons these two bounds actually coincide and hence precisely determine the entropy in question. Furthermore, graphon entropy has a nice connection to the fractional chromatic number and the fractional clique number.

Judgments of learning enhance recall for category-cued but not letter-cued items.

Making immediate judgments of learning (JOLs) during study can influence later memory performance, with a common outcome being that JOLs improve cued-recall performance for related word pairs (i.e., positive reactivity) and do not impact memory for unrelated pairs (i.e., no reactivity). The cue-strengthening hypothesis proposes that JOL reactivity will be observed when a criterion test is sensitive to the cues used to inform JOLs (Soderstrom et al., Journal of Experimental Psychology: Learning, Memory, and Cognition, 41 (2), 553-558, 2015). Across four experiments, we evaluated this hypothesis with category pairs (e.g., A type of gem - Jade) and letter pairs (e.g., Ja - Jade). Participants studied a list comprised of both pair types, made (or did not make) JOLs, and completed a cued-recall test (Experiments 1a/b). The cue-strengthening hypothesis predicts greater positive reactivity for category pairs than for letter pairs, because making a JOL strengthens the relationship between the cue and target, which is more beneficial for material with an a priori semantic relationship. Outcomes were consistent with this hypothesis. We also evaluated and ruled out alternative explanations for this pattern of effects: (a) that they arose due to overall differences in recall performance for the two pair types (Experiment 2); (b) that they would also occur even when the criterion test is not sensitive to the cues used to inform JOLs (Experiment 3); and (c) that JOLs only increased memory strength for the targets (Experiment 4). Thus, the current experiments rule out plausible accounts of reactivity effects and provide further, converging evidence for the cue-strengthening hypothesis.

Cognitive influences on fixational eye movements

We perceive the world based on visual information acquired via oculomotor control,1 an activity intertwined with ongoing cognitive processes.2,3,4 Cognitive influences have been primarily studied in the context of macroscopic movements, like saccades and smooth pursuits. However, our eyes are never still, even during periods of fixation. One of the fixational eye movements, ocular drifts, shifts the stimulus over hundreds of receptors on the retina, a motion that has been argued to enhance the processing of spatial detail by translating spatial into temporal information.5 Despite their apparent randomness, ocular drifts are under neural control.6,7,8 However little is known about the control of drift beyond the brainstem circuitry of the vestibulo-ocular reflex.9,10 Here, we investigated the cognitive control of ocular drifts with a letter discrimination task. The experiment was designed to reveal open-loop effects, i.e., cognitive oculomotor control driven by specific prior knowledge of the task, independent of incoming sensory information. Open-loop influences were isolated by randomly presenting pure noise fields (no letters) while subjects engaged indiscriminating specific letter pairs. Our results show open-loop control of drift direction in human observers.

Garrano Horses Perceive Letters of the Alphabet on a Touchscreen System: A Pilot Study.

This study aimed to use a computer-controlled touchscreen system to examine visual discrimination in Garrano horses (Equus caballus), an endangered breed of pony belonging to the Iberian horse family. This pilot study focused on the perceptual similarity among letters of the alphabet. We tested five horses in a one-male unit (OMU) living permanently in a semi-free enclosure near their natural habitat in Serra d'Arga, northern Portugal. Horses were trained to nose-touch black circles that appeared on the screen. Then, they were tested for discrimination of five letters of the Latin alphabet in Arial font, namely O, B, V, Z, and X, using a two-choice discrimination task. The confusion matrix of letter pairs was used to show the MDS and to identify the relative contribution of shape features. The results showed perceptual similarities among letters with curvatures pitted against those of straight lines. Shape perception in horses seems to share features with that of humans and other animals living in different niches. The touchscreen system proved to be an objective and innovative way of studying cognition in the socially organized group of horses. The automated system can promote the welfare of captive horses by maximizing their freedom of movement.

Numerical estrangement and integration between symbolic and non-symbolic numerical information: Task-dependence and its link to math abilities in adults

Most adults have access to two different number systems to represent numerical information: an exact number system, which relies on different forms of number symbols to represent exact numerical information, and an approximate number system, which allows for approximate estimates of numerical quantities. Here we investigate the integration between the symbolic and non-symbolic numerical information (i.e., “numerical integration”), and how numerical integration relates to adults' formal math abilities. We administered two tasks to measure numerical integration. For a number comparison task with non-symbolic dot arrays and Arabic numerals, participants indicated the larger of two sequentially presented stimuli that were same-format (dot-dot or numeral-numeral), or mixed-format (dot-numeral or numeral-dot). For a number-letter discrimination task, participants identified Arabic numerals or letter pairs that co-occurred with dot arrays (matching or mismatching the quantity represented by the numeral). In the number comparison task, participants were significantly slower when comparing mixed-format stimuli, especially when Arabic numerals were presented first and dot arrays second, suggesting estrangement between symbolic and non-symbolic numerical information and an asymmetry depending on the order in which the numerical information is presented. In contrast, in the number-letter discrimination task, participants were significantly faster in number-letter discrimination for matching dot arrays and numerals, suggesting integration between symbolic and non-symbolic numerical information. Surprisingly, some measures of numerical estrangement derived from the number comparison task significantly correlated with adults' performance on a standardized math assessment. Thus, we conclude that numerical integration or estrangement is task-dependent, and adults with greater levels of symbolic estrangement tend to have higher math skills.

Relative letter-position coding revisited

The notion that the brain achieves visual word recognition by encoding the relative positions of letters with open-bigram representations (e.g., ‘h-e’, ‘h-r’ and ‘e-r’ driving recognition of ‘her’) has been successful in accounting for many behaviors and phenomena. However, one characteristic of open-bigrams has remained unexplored: How is the activation of a bigram modulated by the distance between its constituents in the visual field? On the one hand, contiguous letters (e.g., ‘at’ in ‘father’) may allow for a clearer percept of the bigram. On the other hand, an increasing distance between letters (e.g., ‘ae’ in ‘father’) should create more certainty about their relative positions, which is precisely what the bigram is meant to convey. This matter was investigated with two experiments in which participants indicated whether target pairs of letters occurred in random letter strings. They were instructed that letter order mattered (i.e., ‘a-b’ does not occur in ‘kbac’), while letter contiguity did not (i.e., ‘a-b’ occurs in ‘akcb’). Controlling for crowding and eccentricity, bigrams were recognized faster upon decreasing the letter distance. However, when switching the target letter order (meaning the string should be met by a ‘no’ response), shorter letter distances yielded slower responses and more false positives. Neither relative position-coding models nor absolute position-coding models accommodate both these patterns at once. We discuss how a complete account of our effects may instead combine elements from both model types.

Letter visual similarity of Japanese hiragana and katakana based on reaction times

AbstractLetter similarity (i.e., perceptual distance) is a critical measure to better understand letter perception and literacy development. Despite its importance, however, measurements of letter similarity for non-alphabetic scripts are limited, and the shortage of letter similarity for non-alphabetic script interferes with the identification of the universality and the uniqueness of letter perception systems across different scripts. In the present study, we provide a comprehensive matrix of letter similarity for Japanese kana letters (hiragana and katakana). We obtained the discrimination reaction times for simultaneously presented letter pairs and calculated the perceptual distance of 4,278 letter pairs by inversing the time. The matrix showed significant correlations with previously obtained letter similarity for hiragana and katakana. An additional experiment showed that letter pairs for the same sounds (え–エ) produced significantly slower responses compared with those for different sounds (え–コ). However, the differences in reaction times between the same and different sound conditions were smaller than the sequentially presented conditions, suggesting that the matrix was partially attributable to knowledge-based factors (e.g., letter-sound knowledge). This first comprehensive matrix of letter similarity (i.e., perceptual distance) for Japanese kana letters (hiragana and katakana) will be useful for researchers interested in letter perception and literacy development.

Emergence of a compositional neural code for written words: Recycling of a convolutional neural network for reading

The visual word form area (VWFA) is a region of human inferotemporal cortex that emerges at a fixed location in the occipitotemporal cortex during reading acquisition and systematically responds to written words in literate individuals. According to the neuronal recycling hypothesis, this region arises through the repurposing, for letter recognition, of a subpart of the ventral visual pathway initially involved in face and object recognition. Furthermore, according to the biased connectivity hypothesis, its reproducible localization is due to preexisting connections from this subregion to areas involved in spoken-language processing. Here, we evaluate those hypotheses in an explicit computational model. We trained a deep convolutional neural network of the ventral visual pathway, first to categorize pictures and then to recognize written words invariantly for case, font, and size. We show that the model can account for many properties of the VWFA, particularly when a subset of units possesses a biased connectivity to word output units. The network develops a sparse, invariant representation of written words, based on a restricted set of reading-selective units. Their activation mimics several properties of the VWFA, and their lesioning causes a reading-specific deficit. The model predicts that, in literate brains, written words are encoded by a compositional neural code with neurons tuned either to individual letters and their ordinal position relative to word start or word ending or to pairs of letters (bigrams).

Chunking is not all-or-none: hierarchical representations preserve perceptual detail within chunks

Objects are not stored as unitary representations: memory representations are hierarchically structured in that objects structure memory, but features within objects are mostly independent (Fougnie et al. 2013). Yet prominent chunk learning theories still treat learned chunks as all-or-none bound representations (e.g., in visual memory, “content-free labels”, Huang & Awh, 2018). Here we suggest that as in the case of objects themselves, chunks that combine objects are also hierarchically structured, with preserved information about their contents in addition to the chunk ‘pointer’. We tested this in two ways: In Experiment 1 and 2, we had participants learn new ‘chunks’ using the color-pair paradigm of Brady et al. (2009), in which colors frequently co-occur next to each other in a working memory paradigm (e.g., orange frequently co-occurs with green). However, unlike previous work where the colors were identical on every trial, the colors in these experiments varied in luminance: so although green frequently occurred with orange, the particular green and orange on each trial were unique. We found that (1) learning significantly improved capacity over the experiment; (2) after learning, knowledge about the 2 colors was correlated, showing some binding; and yet (3) participants did not simply encode abstractions (“irish flag colors”), but had preserved knowledge of trial-specific color information as well. In Experiment 3, we relied on existing chunks. Participants were instructed to remember known words (e.g., “GO”) or unknown letter pairs (e.g., “SP”), with letter fonts varying from trial to trial. The presence of pre-existing word chunks helped not only in knowing the letters but also improved knowledge of the fonts -- which contradicts predictions made by a content-free labels account. Overall we find evidence that memory should be considered hierarchical: Chunks, like objects, serve as cues to access specific information within them, rather than serving as all-or-none abstractions.

Implementasi Algoritma Kriptografi Playfair Cipher untuk Mengamankan Data Aset

Data sangatlah penting untuk manusia, data juga dibutuhkan untuk mengumpulkan informasi. Namun mengingat kejahatan cybercrime sudah banyak terjadi di era digital saat ini. Oleh karena itu, keamanan data menjadi hal yang sangat penting untuk diperhatikan. Didalam perusahaan mempunyai data penting. Salah satunya perusahaan di Karawang yaitu PT Adyawinsa Stamping Industries terdapat aplikasi penginputan data yaitu data aset perusahaan. Banyaknya masalah kejahatan data membuat sistem basis data rentan untuk dimanipulasi. Oleh sebab itu, dilakukan implementasi keamanan data terhadap data aset dengan menggunakan kriptografi Playfair Cipher. Playfair Cipher ini mengenkripsikan pasangan huruf (bigram atau digraf) menjadi pasangan huruf, bukan huruf tunggal seperti pada cipher klasik lainnya. Tujuan penelitian ini adalah aplikasi yang mampu melakukan enkripsi data dengan menggunakan algoritma kriptografi Playfair Cipher dan aplikasi juga mampu melakukan dekripsi dari data di dalam database telah dienkripsi kemudian memasukkan data yang telah dienkripsi ke dalam database Hasil dari penelitian ini menunjukkan bahwa sistem yang dibangun telah berhasil melakukan enkripsi dan dekripsi data aset terhadap nama user dan nama aset dengan menggunakan algoritma kriptografi Playfair Cipher. Terdapat perbedaan hasil dekripsi yang diuji dalam penelitian ini. Akan tetapi, aplikasi dapat mengatur hasil dekripsi dengan tools yang terdapat di dalam aplikasi.

The Mirror Generalization Process in Reading: Evidence from Korean Hangul.

Mirror invariance or generalisation is the ability to recognise objects as being the same regardless of their spatial orientation. However, when, for example, learning to read Roman script, children need to hone these skills so that they can readily discriminate between mirror letters such as b/d or p/b. Korean Hangul makes a particularly interesting comparison as it has both lateral and vertical perceptually similar mirror letter pairs (i.e., ㅏㅓ, ㅑㅕ, ㅗㅜ, ㅛㅠ). In the current study, we investigated the mirror generalisation effect in native readers of Korean Hangul. We used a similar negative priming paradigm as used by (Ahr et al., Brain and Cognition 117:1-8, 2017) with Roman script readers. In contrast to their findings, we did not find evidence of negative priming due to either lateral (e.g., ㅏ + ㅓ) or vertical (e.g., ㅗ + ㅜ) mirror letter primes in Korean readers. One explanation for these results is that adult readers of Korean Hangul may not experience mirror invariance to the same extent as Roman script readers due to script-specific characteristics. Thus, learning to read this distinctive script may result in readers being less sensitive to mirror reversals than Roman script readers.

A causal role for the cerebellum in semantic integration: a transcranial magnetic stimulation study

Mounting evidence suggests that the cerebellum, a structure previously linked to motor function, is also involved in a wide range of non-motor processes. It has been proposed that the cerebellum performs the same computational processes in both motor and non-motor domains. Within motor functions, the cerebellum is involved in the integration of signals from multiple systems. Here we hypothesized that cerebellum may be involved in integration within semantic memory as well. Specifically, understanding a noun-adjective combination (e.g. red apple) requires combining the meaning of the adjective (red) with the meaning of the noun (apple). In two experiments, participants were asked to judge whether noun-adjective word-pairs were semantically related (e.g., red apple) or not (e.g., lucky milk) while online transcranial magnetic stimulation (TMS) was administered over the right cerebellum or over a control site (vertex in Experiment 1 and visual cortex in Experiment 2). Cerebellar TMS caused a decrease in participants’ accuracy for related word-pairs while accuracy for unrelated stimuli was not affected. A third experiment using a control task where subjects compared pairs of random letters showed no effect of TMS. Taken together these results indicate that the right cerebellum is involved specifically in the processing of semantically related stimuli. These results are consistent with theories that proposed the existence of a unified cerebellar function within motor and non-motor domains, as well with recent perspectives about cerebellar involvement in semantic memory and predictive cognition.

Topological difference between target and flankers alleviates crowding effect

In the crowding effect, object recognition in the periphery deteriorates when other items flank the target, especially if they share similarities. Here, we report that the similarity defined by topological property (differences in number of holes) influences the crowding effect. Orientation discrimination tasks suggested that the crowding effect was weaker with a topological different (TD) flanker than a topological equivalent (TE) flanker and an existing inward-outward anisotropy phenomenon. In another experiment, both an outer and an inner flanker were used to constitute four different conditions. The performance of an outer TD flanker and an inner TE flanker was superior to that of an outer TE flanker and an inner TD flanker, even though the items of the stimuli were the same. Different stimuli were used to control for local features. To eliminate the possible explanation of confusability, we selected pairs of letters with matched confusability, but one pair was TD and another was TE. The letter identification performance was better for the TD condition. Lastly, we investigated the digit identification under four conditions with varied spacing. Regardless of different spacing, the crowding effect was reduced by a topological different flanker. The results collectively suggest that topological property plays a role in the perceptual grouping, which modulates the crowding effect.

New symmetric key cipher capable of digraph to single letter conversion utilizing binary system

In this paper, a new Playfair cipher built on bits level symmetric key cryptographic was proposed for the purpose of converting pairs of letters (digraphs) into single letters. The proposed algorithm is capable to overcome many of the shortcoming and vulnerabilities that exist in the current classical version of Playfair algorithm. The Playfair cipher is exceedingly complex than a classical substitution cipher, but still simple to hack using automated tactics. It is famous as a digraph cipher because two letters are exchanged by other two letters. This destroys any solo letter occurrence statistics, but the digraph statistics still unaffected (frequencies of two letters). Unluckily letter pairs have a flatter distribution than the one letter frequencies, so this intricacy matters for solving the code using pen and paper procedures. The suggested encryption process is conducted as follows; letters are first arranged in a spiral manner in Polybius square, afterwards, each pair will be replaced utilizing before-after technique if we are arranging pairs horizontally and down-up technique (vertically). The former process produces pairs of Plaintext that will be converted to binary bit stream then will be divided over blocks with stable sizes. Bits of these blocks are taken from pairs then fit them into square matrix of suitable order to put the concept of row-wise and revers row-wise matrix. Bits of this matrix are split into 2x2 square matrixes. The sub-matrixes are formed 8 bits. Here the XNOR operation is taken into consideration for bitwise operation to generate the keys for decryption and produce the cipher-text.

Correspondence Between Citizens and Executive Power: Correlative Text Analysis

This article refers to the material of written appeals made by citizens to executive bodies and official responses to the appeals. The authors proceed from the fact that it is possible to objectively assess the quality of written responses to citizens’ appeals only when they are considered together with the initial appeals of the citizens. The authors use an innovative method, applying the linguistic textual approach to the analysis of pairs of business letters. Correlative linguistic textual analysis is demonstrated in the field of two text categories: theme and composition. The article shows the thematic correlation between the response and the original business letter and highlights the most common violations of the categorial thematic correlation (shift of the subject matter of the original letter, incomplete thematic correspondence of the text units in the pair, etc.). The analysis of composition is based on the model composition signs of the letter of appeal and the official reply. Theoretical observations of the linguistic textual character are relevant to the practice of composing official response letters to citizens’ appeals. The use of correlative linguistic text analysis opens an opportunity to objectively evaluate the logical and linguistic quality of the official response letter and develop a methodology for composing response letters on the basis of the source texts.

Application of a genetic algorithm to the keyboard layout problem.

The number of people who use computers for business and personal purposes increases as technology grows. The application of ergonomic practices on computer workstations reduces the musculoskeletal discomfort experienced and increases the overall satisfaction of the users. Keyboards are available in various systems, from computers to mobile devices, and have difference shapes and sizes. The keyboard size and shape is known to influence the user’s upper extremities. Alternative keyboard designs help diminish the pain in the arms that occurs due to awkward arm postures. Most previous studies tried to optimize the keyboard layout based on ergonomic typing and the frequency of letters’ co-occurrence. This research considers the frequency of the appearance of the most used 3,000 words in the English language. First, the frequency of each letter pair is calculated by the Text Analyzer. Then, a genetic algorithm is applied to design an ergonomically optimized keyboard to minimize the total distance of finger travel among the selected alphanumeric characters. The results showed that the distance travelled obtained by the proposed keyboard layout is less than that for the QWERTY keyboard in all different types of texts, in which an average of 6.04% improvement was achieved. Therefore, the proposed design can be used for keyboards to reduce time and fatigue.

The black superiority effect: Black is taller than gray

A novel illusion entitled “the letter height superiority effect” has been demonstrated. This shows that letters are perceived as being taller than pseudoletters, while in reality their objective sizes are identical. An explanation of this illusion has been proposed in the framework of the Interactive Activation Model. Indeed, we postulated that the more a feature is activated, the taller a stimulus is perceived as being. The objective of the current study was to test this postulate by manipulating feature activation through signal-to-noise ratio. We presented gray stimuli (low signal-to-noise ratio) or black ones (high signal-to-noise ratio). In a first experiment, participants judged the size of pairs of either letters or pseudoletters presented as black or gray. In a second experiment we presented pairs consisting of a letter and a pseudoletter, of identical or different colors. In a third experiment, we presented pairs of letters or pseudoletters of identical or different colors by block to test the possible effect of previous exposure on perceptual judgments. The results showed that for identical objective size, participants perceive black stimuli to be taller than gray ones and that the effects of the nature of the stimuli and their color are cumulative. The results also indicated that the effects were not due to previous exposure to color or sizes. These results confirm the Interactive Activation Model as a credible explanation for the letter height superiority effect.

Time-conjunctive representations of future events.

It is widely accepted that people can predict the relative imminence of future events. However, it is unknown whether the timing of future events is represented using only a "strength-like" estimate or if future events are represented conjunctively with their position on a mental timeline. We examined how people judge temporal relationships among anticipated future events using the novel Judgment of Anticipated Co-Occurrence (JACO) task. Participants were initially trained on a stream of letters sampled from a probabilistically repeating sequence. During test trials, the stream was interrupted with pairs of probe letters and the participants' task was to choose the probe letter they expected to appear in the stream during a lagged target window 4-6 items (4.3-8.5 s) in the future. Participants performed above chance as they gained experience with the task. Because the correct item was sometimes the more imminent probe letter and other times the less imminent probe letter, these results rule out the possibility that participants relied solely on thresholding a strength-like estimate of temporal imminence. Rather, these results suggest that participants held (1) temporally organized predictions of the future letters in the stream, (2) a temporal estimate of the lagged target window, and (3) some means to compare the two and evaluate their temporal alignment. Response time increased with the lag to the more imminent probe letter, suggesting that participants accessed the future sequentially in a manner that mirrors scanning processes previously proposed to operate on memory representations in the short-term judgment of recency task.

Microscopic path structure of optimally aligned random sequences

Considering optimal alignments of two i.i.d. random sequences of length $n$, we show that for Lebesgue-almost all scoring functions, almost surely the empirical distribution of aligned letter pairs in all optimal alignments converges to a unique limiting distribution as $n$ tends to infinity. This result helps understanding the microscopic path structure of a special type of last-passage percolation problem with correlated weights, an area of long-standing open problems. Characterizing the microscopic path structure also yields robust alternatives to the use of optimal alignment scores alone for testing the homology of genetic sequences.