Choice Of Symbols Research Articles

Symbol-Based Modeling and Coding of Block Markov Sources

Industry-standard lossless compression algorithms (such as LZW) are usually implemented so that they work on bytes as symbols. Experiments indicate that data for which bytes are not the natural choice of symbols compress poorly using these implementations, while algorithms working on a bit level perform reasonably on byte-based data in addition to having computational advantages resulting from operating on a small alphabet. In this correspondence, we offer an information-theoretic explanation to these experimental results by assessing the redundancy (which is approximated by the divergence rate of two source distributions) of a bit-based model when applied to a byte-based source. More specifically, we study the problem of approximating a block Markov source (our model for byte-based data) with higher order Markov sources (which model bit-based Markov encoders), and show that the divergence rate between a block Markov source and the best matching higher order Markov model for that source converges to zero exponentially fast as the memory of the model increases. This result is applied to obtain bounds on the redundancy of certain symbol-based universal codes when they are used for byte-aligned sources

Using the Multimodal Communication Screening Test for Persons with Aphasia (MCST‐A) to guide the selection of alternative communication strategies for people with aphasia

Background: People with severe communication problems associated with aphasia and concomitant apraxia of speech are often unable to meet their daily communication needs through speech alone. For these people, augmentative and alternative communication (AAC) strategies may offer opportunities for improved communication effectiveness. However, it can be challenging to determine if individuals can learn to use alternative communication strategies independently or if they will require assistance from conversational partners to participate in meaningful communication interactions. Aims: The authors developed an assessment tool, the Multimodal Communication Screening Task for Persons with Aphasia (MCST‐A; Garrett & Lasker, 2005b), to help clinicians differentiate those individuals who would benefit most from partner‐dependent communication strategies (e.g., written choice conversation, partner‐presented symbol choices, tagged yes/no questions) and those who could learn to use AAC systems (e.g., digitised speech devices that store complete messages; multi‐level devices with stored messages and spelling capabilities) to communicate independently. This article describes the tool and its administration protocol. We also compare MCST‐A scores to profiles of actual communication strategy use for four individuals across a range of aphasia severity. Methods & Procedures: Four individuals with communication disabilities associated with aphasia were asked to locate pictorial, textual, or graphic symbols from an eight‐page stimulus manual to communicate simple needs and complex concepts, complete simple categories, tell and retell stories, or use partial spelling to convey novel information. Accuracy of responses and the amount and type of cueing required to complete each simulated communication task were tallied for each individual. MCST‐A test results are discussed in light of each individual's observed pattern of AAC strategy and system use both during and following functional communication treatment. Results: Descriptive analyses of the four cases revealed a correspondence between MCST‐A test scores, level of impairment as measured by the Western Aphasia Battery (Kertesz, 1982), and patterns of communication strategy use. The two individuals who received the lowest response accuracy scores and the highest cueing scores on the MCST‐A were primarily dependent on partner‐supported communication strategies in their daily lives. The two individuals with the lowest cueing scores and highest response accuracy scores had learned to use complex AAC communication devices to communicate independently and generatively in community settings. Conclusions: The hierarchy of scores seen on the MCST‐A corresponded with individuals' abilities to communicate using AAC strategies after participating in functional therapy. The MCST‐A may guide clinicians in identifying the most appropriate AAC strategies for individuals with aphasia. Further validation is warranted.

Symbol communication in special schools in England: the current position and some key issues

In this article, originally submitted to B J S E‘s Research Section, Chris Abbott of King's College, London, and Helen Lucey of the Open University report on the outcomes of a survey of special schools in England. The aim of the research, funded by the Nuffield Foundation, was to understand the nature and extent of symbol use for communication and literacy. A questionnaire was used to collect data on topics including: the types of symbols in use; the methodologies operated; ownership of symbol choice; and agreed policies within and outside school. The researchers had an excellent response in this important survey, undertake n after a period of rapid growth in symbol use in special schools and elsewhere. Chris Abbott and Helen Lucey provide a discussion of the results of their survey and of the issues that arise from the findings and the many comments added by respondents. They close their article with a call for further detailed research, both in the UK and in co-operation with practitioners in other countries, into the ways in which symbol use can meet the needs of learners. [ABSTRACT FROM AUTHOR]

Geochemical mapping: technique or art?

Various techniques for producing geochemical maps are reviewed. Interpretation of processes leading to the observed element distribution will be facilitated when the data structure is displayed in a geochemical map. This can be achieved by using the boxplot or percentiles, evenly spread over the whole data range, for class selection. Map scale (to purpose), type and amount of background map information, choice of symbols (black-and-white mapping) and, for colour maps, the colour scale are important issues that need consideration.

Factors influencing the algebra “reversal error”

Given a written problem statement about a proportional relationship between two quantities, many students will place the constant of proportionality on the wrong side of the equals sign. Introductory physics is one of the first courses in which students encounter multiple-step problems that require algebraic (rather than numeric) solutions, and this “reversal error” is relatively common in student solutions to these types of problems. We describe an investigation into three possible influences on students who make this reversal error: variable symbol choice, sentence structure, and context familiarity. Our results, from a calculus-based physics course and an intermediate algebra course, show that sentence structure is the most significant of these three possibilities. However, sentence structure alone does not provide a complete explanation for the reversal error.

The world of touch: an international survey of tactile maps. Part 2: design

This paper reports the findings of an international survey that collected data on production methods, techniques, outputs and design preferences among tactile map producers, designers and researchers worldwide. A number of consistencies and inconsistencies are identified and we speculate on the extent to which the current state of tactile map production is likely to meet the needs of the client population. In this second part of the report we focus on issues of map design, such as the choice of map size and format, and choice of symbols. We also report answers to a series of open-ended questions on respondents' approach to addressing user needs.

The magnetism of songs

One striking feature of the student demonstrations in Indonesia in the months before and after President Soeharto's fall from power was the choice of patriotic symbols.1 No protest rally seemed complete without students singing nationalist songs. Another indispensable feature of many of the demonstrations was a long march. Both the patriotic lyrics and the long marches are signs of the success of Indonesia's New Order indoctrination and the special brand of nationalism the military tried to inculcate. The long marches, invariably referred to as such in English, are reminiscent of the heroic march of soldiers of the Siliwangi army division returning from Central Java to their home base in West Java in 1948. Forced to withdraw to Indonesian Republican territory after the Renville Agreement of 17 January 1948, the troops, accompanied by their families, began their wearying return journey to West Java after the launching of the Second Dutch Military Action on 18 December 1948. Of course, the students' long marches were much shorter than this, often no more than a walk around the periphery of a campus or a hotel, or through one part of a town. Some of the nationalist songs, known in Indonesian as lagu perjuangan, 'struggle songs' (or occasionally as lagu pahlawan, 'heroes' songs'), glorify the Indonesian Revolution and the struggle for independence from the Dutch. That protesting students sang nationalist songs with such enthusiasm requires some explanation. Another term for one group of such songs is lagu wajib, 'compulsory songs', referring to the fact that schoolchildren are obliged to sing them (and a lot of other songs which glorify the nation or voice official ideology and as such form part of a larger indoctrination campaign)

Meaningful Mathematical Representations and Early Algebraic Reasoning

Both oral and written communication play an important role in teaching and learning mathematics (NCTM 2000). Students and teachers exchange ideas about their understanding of, and thinking about, mathematics by communicating with one another. An important part of this communication process is the choice of symbols used to represent that thinking (Hiebert 1989). The process of representing mathematical ideas using symbols and expressions should begin at the earliest stages of mathematics instruction and appear in the context of ideas to which young students can relate (Carey 1992).

BER performance analysis of a direct conversion receiver

Direct conversion receivers are increasingly popular for use in mobile terminals. This is due to advantages over other architectures such as heterodyne receivers in terms of cost, electrical current, and physical size. However, a direct conversion receiver often generates a DC-offset that has to be taken care of either by suppressing the DC-offset in the radio-frequency part of the receiver, or by taking care of it during baseband processing. A theoretical analysis of the bit error rate (BER) performance in a direct conversion receiver with different levels of DC-offset suppression is presented. Explicit results are presented on how the BER depends on the signal-to-noise ratio (SNR), the signal-to-DC-level, and the choice of pilot symbols both with M-QAM and M-PSK in a slow, flat Rayleigh fading channel. A design rule, which applies to the design of DC-compensation in direct conversion receivers, is also presented.

Intersubjectivity and understanding rock art

Intersubjectivity and understanding rock art

Setac-Europe reaches 1,000 members!

Setac-Europe reaches 1,000 members!

Are faces special for sheep? Evidence from facial and object discrimination learning tests showing effects of inversion and social familiarity

We have previously shown that sheep, like monkeys, have neural circuits within the temporal lobe that respond preferentially to faces. They can also discriminate between sheep, humans and other animals on the basis of facial cues using an enclosed Y-maze. In the present study we investigated the speed with which Clun Forest sheep learn to discriminate between familiar and unfamiliar faces, as opposed to symbols, in order to gain a food reward using the same Y-maze apparatus. Animals ( n = 10) received 1 day of training where projected images of the pairs of faces or symbols were paired for 20 trials with a picture of either an empty or full bucket of food (which indicated which choice of face or symbol would result in the animal receiving a food reward) and on the next 4 days they were given a further 20 trials a day with the faces or symbols alone. Results showed that sheep learned significantly faster (by day 1 or 2 post training) to recognise sheep faces of a familiar breed compared to geometrical symbols (3–4 days post training). Learning using faces of animals of another unfamiliar breed was also significantly better than for symbols but was significantly worse than that seen using faces of a familiar breed. Inverting the faces significantly reduced learning speed for faces of a familiar breed but not for that of an unfamiliar one. Inverting familiar objects, food buckets, also did not impair discriminatory performance. In a further set of trials where discrimination learning was made more difficult by excluding cued trials and reducing the number of daily trials to eight, social familiarity was found to further improve the animal's ability to learn to discriminate between the faces of a familiar breed. Finally, while discriminatory performance for adult sheep faces was very good, that for young lamb faces was poor, with only one animal learning to choose the face associated with food. It was confirmed in maternal ewes that they were also slow to learn to recognise the faces of their lambs (2–3 weeks). Overall these results show that sheep can learn to distinguish between individual adult sheep faces but that breed and social familiarity influence the level of performance. Further, discrimination learning of familiar and unfamiliar facial stimuli is better than between simple geometrical symbols, indicating that faces may be preferentially processed by the brain compared to other objects suggesting that faces are indeed special in this species as has been claimed for human and non-human primates.

An essay on culture: symbolic structure and social structure

Drawing on scholarship and personal experience, Berger here reviews and synthesizes recent work in cultural sociology from a materialist perspective. His essay culminates in a call for an empirical research programme focused on the relation between symbolic choices and social locations, rather than on interpretive accounts of the meanings of texts or performances.

Children's invented symbol systems: Exploring parallels between music and mathematics.

This is a short report of an exploratory study linking children's invented mathematical notations and music notations. Ten 8-year-old children participated in the study. Prior research in music notations has indicated that children have a variety of symbols at their disposal, and their choice of symbols depends on the entity they are trying to capture. This was also the case for notations of tessellations. Although there were similarities found between the use of symbols in the two domains, a consideration of the intended reader did not appear to be a contributing factor in designing mathematical notations. This research note describes the first of four phases of the research comparing children's invented notations for mathematics and music. The overall aims of the research are to explore the authentic connections between music and mathematics in terms of notations, as well as form and transformations, and to adapt methodologies used in researching children's music cognition to address parallel situations in mathematics. There is much to learn from the research on music notations in advancing our understanding of mathematics notations. A diverse body of research indicates that children use a rich and varied repertoire of symbols and strategies in notating rhythm sequences and melodies. They notate with pictures or icons, letters and words, numbers, lines and squiggles and crosses, music symbols, and color to create engaging systems of recording the music they (Bamberger, 1982; Davidson & Colley, 1986; Davidson & Scripp, 1988; Davidson, Scripp, & Welsh, 1988; Smith, 1989; Upitis, 1987, 1990a) and compose (Borstad, 1989; Upitis, 1990b, 1992). In an examination of the research on children's music notations, three other features consistently emerge. The first is that children are more likely to engage in exploring and using music notations when they are involved in making something that they value as real—perhaps composing a piece that others will in a class concert (Upitis, 1992). Second, research on music notations indicates the importance of the intended or imagined reader. Children are less likely to use music symbols if they know that the person who will be reading their notation is not fluent in standard notation (Upitis, 1990a, 1992). Finally, research indicates that when children truly embrace an idea, they make it a part of their world, using the idea to see the everyday phenomena in new ways (Hodgkin, 1985). Thus, children who become musicians and composers may hear the music in the pattern on a sweater or in a mosaic (Upitis, 1990b).

Discussion Contribution to the "Foundation of the Structural and Form Analysis of Folk Dance"

From our point of view we wish to differentiate four points: 1. The system of form analysis as such (correctness and consequentiality of the system in all its parts). 2. The type of graphic representation (choice of symbols, indexes, and signs, the types of tables, etc. ) which are differentiated by the analytic system (and some of which members of our group have occasionally used differently). 3. The type of definition in the system (formulations, comprehensibility of parts of the Syllabus, exactness of explanation, sufficiency of examples). 4. Demonstration of the usefulness of the analytic system for the ethnochoreologic -practice (e.g. for methods of comparison of various dances, for determination of their development, their age, their change in function, etc.), and the degree and role that form contributes to classification of folk dances. (Point 4 relates to the introductory chapter.) (I have used with success the form structural analysis in my examples to the paper Fragen und Gedanken zur Klassifikationsproblematik in Der Altere Paartanz in Europa, proceedings of the 1980 conference in Stockholm: Arkivet for Folklig Dans.)

User Perceptions of Bi-Symbol Maps

Cartographers continue to be concerned with differences that arise between what a designer intends a map to communicate and what users perceive the map to convey. Symbol choice and presentation, in relationship to the process by which users apprehend maps, appear to be the core issues in this concern. This paper examines designer-user disparity within the context of perceptual and task-related responses to two-symbol map depictions of a single theme. It assesses users' perceptions of differences among versions of a bi-symbol map with regard to their usefulness for point estimating. To elicit users' perceptions, the study employed three series of this bi-symbol map, each created by varying the presentation of one or the other or both symbols. The study used a multi-dimensional scaling design to examine the participants' perceptions for their universality and for what they may say about this type of map, symbol choice and symbol presentation. The results from such an examination, while not surprising, prove to have implications for all of these issues.

Subliminal Stimulation, Choice Behavior and Some Personality Correlates of Subliminal Sensitivity

The aim of this study was to investigate the possible relations between specific personality variables and the effect of subliminal stimulation on choice behavior. It was hypothesized that subjects with low anxiety, less neuroticism, and external locus of control and the trait of extraversion would be more susceptible to subliminal stimulation. 38 undergraduate students were exposed to subliminal messages urging them to choose symbols instead of numbers or letters. Analysis showed that subliminal stimulation did not generate a preference for symbols over numbers or letters. No support was observed for the hypothesis of an association between susceptibility and personality variables. These results may be explained in terms of symbol choice being a neutral message that did not relate to the subjects' needs and motivation.

The choice of names and symbols for quantities in chemistry

The importance of maintaining a clear distinction between the names and symbols for quantities and the names and symbols for units.

On the Substantiality of Form: Interpreting Symbolic Expression in the Paradigm of Social Organization

The publication of Sir James Frazer's Totemism and Exogamy raised as many problems for anthropologists as it tried to solve: namely, why do symbols that stand for any social group become imbued with religious, ritual, social, and mystical significance, and how do these totemic conceptual systems relate to systems of action? More often than not, symbols of group unity—whatever the group—possess more than one dimension, and these dimensions are often hard to differentiate analytically and ethnographically. In the mainstream of anthropology symbols and their use have been deemed to reflect patterns of social organization. Within this paradigm the majority of authors treat the choice of symbol as either essentially arbitrary or deterministically compelled. We find that the old paradigm of symbol as a reflection of something essentially social—cultural inversion, as some authors would have it, or vaguely and vulgarly determined as others put it—is rather suspect.

Applications of a Cartographic Communication Model to Tactual Map Design

Cartographic communication models provide a framework for mapping decisions. The models help the cartographer formulate ideas on map content, symbol choice, design and message. They also stress the importance of effectively transmitting the map message based on knowledge of the map recipient's characteristics. This paper presents a practical application of the theory outlined in a communication model. It does so by examining the mapping decisions required in communicating geographic information in tactual form to visually impaired persons. The tactual map reader, map reading process, symbols, lettering, content, design and production methods are discussed in the context of the model. Some suggestions are offered for introducing these topics in the classroom.