Dynamic Text Research Articles

Compressed indexes for dynamic text collections

Let T be a string with n characters over an alphabet of constant size. A recent breakthrough on compressed indexing allows us to build an index for T in optimal space (i.e., O ( n ) bits), while supporting very efficient pattern matching [Ferragina and Manzini 2000; Grossi and Vitter 2000]. Yet the compressed nature of such indexes also makes them difficult to update dynamically. This article extends the work on optimal-space indexing to a dynamic collection of texts. Our first result is a compressed solution to the library management problem, where we show an index of O ( n ) bits for a text collection L of total length n , which can be updated in O (| T | log n ) time when a text T is inserted or deleted from L ; also, the index supports searching the occurrences of any pattern P in all texts in L in O (| P | log n + occ log 2 n ) time, where occ is the number of occurrences. Our second result is a compressed solution to the dictionary matching problem, where we show an index of O ( d ) bits for a pattern collection D of total length d , which can be updated in O (| P | log 2 d ) time when a pattern P is inserted or deleted from D ; also, the index supports searching the occurrences of all patterns of D in any text T in O ((| T | + occ )log 2 d ) time. When compared with the O ( d log d )-bit suffix-tree-based solution of Amir et al. [1995], the compact solution increases the query time by roughly a factor of log d only. The solution to the dictionary matching problem is based on a new compressed representation of a suffix tree. Precisely, we give an O ( n )-bit representation of a suffix tree for a dynamic collection of texts whose total length is n , which supports insertion and deletion of a text T in O (| T | log 2 n ) time, as well as all suffix tree traversal operations, including forward and backward suffix links. This work can be regarded as a generalization of the compressed representation of static texts. In the study of the aforementioned result, we also derive the first O ( n )-bit representation for maintaining n pairs of balanced parentheses in O (log n /log log n ) time per operation, matching the time complexity of the previous O ( n log n )-bit solution.

On a mechanism of stabilizing turbulent free shear layers in cavity flows

Turbulent free shear flows are subject to the well-known Kelvin–Helmholtz type [Panton RL. Incompressible flow. John Wiley and Sons; 1984. p. 675] instability, and it is well-known that any free shear flow which approximates a thin vorticity layer will be unstable to a wide range of amplitudes and frequencies of disturbance. In fact, much of what constitutes flow control in turbulent free shear layers consists of feeding a prescribed destabilizing disturbance to these layers. The question in the control of free shear flows is not whether the shear layer will be stable, but whether you can influence how the layer becomes unstable. In most cases, since these flows are so receptive to forcing input, and naturally tend toward instability, large changes in flow conditions can be achieved with very small amplitude periodic inputs. Recently, it has been discovered that turbulent free shear flows can also be stabilized using periodic forcing. This is, at first glance, counter-intuitive, considering our long history of considering these flows to be very unstable to forcing input. It is a phenomenon not described in modern fluid dynamic text books. The forcing required to achieve this effect (which we will call turbulent shear layer stabilization) is of a much higher amplitude and frequency than the more traditional type of shear layer flow control effect seen in the literature (which we will call turbulent shear layer destabilization). A numerical study is undertaken to investigate the effect of frequency of pulsed mass injection on the nature of stabilization, destabilization and acoustic suppression in high speed cavity flows. An implicit, 2nd-order in space and time flow solver, coupled with a recently developed hybrid RANS-LES (Reynolds Averaged Navier Stokes-Large Eddy Simulation) turbulence model by Nichols and Nelson [Nichols RH, Nelson CC. Weapons bay acoustic predictions using a multi-scale turbulence model. In: Proceedings of the ITEA 2001 aircraft-stores compatibility symposium, March 2001], is utilized in a Chimera-based parallel format. This tool is used to numerically simulate both an unsuppressed cavity in resonance, as well as the effect of mass-addition pulsed jet flow control on cavity flow physics and ultimately, cavity acoustic levels. Frequency (and in a limited number of cases, amplitude) of pulse is varied, from 0 Hz (steady) up to 5000 Hz. The change in the character of the flow control effect as pulsing frequency is changed is described, and linked to changes in acoustic levels. Limited comparison to 1/10th scale experiments is presented. The observed local stabilization of the cavity turbulent shear layer, when subjected to high frequency pulsed blowing, is shown in simulation to be the result of a violent instability and breakdown of a pair of opposite sign vortical structures created with each high frequency “pulse”. This unique shear layer stabilization behavior is only observed in simulation above a certain critical pulsing frequency. Below this critical frequency, pulsing is shown in simulation to provide little benefit with respect to suppression of high cavity acoustic levels.

The Use of Dynamic Text in the Communication Process

Principles concerning appropriate sizes, line length and line spacing for reading matter are studied by several researchers (Black, 1990). In practice (White, 2003), the best text type is so comfortable that it is invisible (transparent), i.e. the reader is not aware of the act of reading. The way in which designer uses the space on the page greatly affects how easily the reader can understand and retrieve the information from it (Hartley, 1994). Digital possibilities of connecting spatial with textual data dynamically may guide reader's attention and increase reader's capability of understanding, memorizing and learning textually presented information. The effects of dynamic visuals on information acquisition have been investigated by several researchers (Angelin et al, 1996). Motion typography can convey ideas, aesthetics and evoke responses. The motion variables of dynamic text include alternations of font's proportions, changes over time and changes in motion directions. The research will examine and evaluate possible merits and dangers of dynamic text usage for transparent readability. The aims are to determine relationships between font (type, size), line (length, spacing) and motion (speed, direction) for better readability. Students from The Faculty of Graphic Arts, Graphic Design Department, are chosen as the observers for visual evaluation.

Development of a web-based graduate-level module courseware

This article presents a survey analysis conducted in and the implementation of a web-based courseware for a graduate-level module on Rapid Response Manufacturing. A courseware website has been developed using HyperText Markup Language, JavaScripts, and Cascading Style Sheets. The website designed is of a hierarchical design. To allow students to navigate easily in this website, a navigation menu that resembled the popular Microsoft Outlook is hence chosen. The website contains course materials, which serve either as introductory materials or pre-class reading materials, and serves to bridge professors and students. The colors scheme and layout used for the website were carefully chosen to achieve a professional look, and the course materials are informative and meaningful. The course materials are presented in an interactive manner using templates created using Macromedia Flash. Using Flash movies, students are able to choose any topic of their choice easily with the click of the mouse. Some animations and mouse rollover effects are also incorporated into the Flash movies for an increased visual experience. The use of dynamic text in Flash movies also greatly improves the way course contents are maintained on the website, allowing the courseware to be easily updated by the lecturers themselves as the materials for the graduate module are updated as technologies in Rapid Response Manufacturing advance. © 2006 Wiley Periodicals, Inc. Comput Appl Eng Educ 14: 90–105, 2006; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20069

Dynamic Text Comprehension

Reading is one of the most complex and uniquely human of cognitive activities. Our understanding of the processes and factors involved in text comprehension is quite impressive, but it also is fragmented, with a proliferation of “mini-theories” for specific components that in reality are intertwined and interact with one another. Theories of dynamic text comprehension (DTC) aim to capture the integration of these components. They depict reading comprehension as an ongoing process involving fluctuations in the activation of concepts as the reader proceeds through the text, resulting in a gradually emerging interpretation of the material. Features of texts and characteristics of the reader jointly and interactively affect these fluctuations, influencing and being influenced by the reader's understanding and memory of what is read. We illustrate the DTC approach by describing one theory, called the Landscape model, and summarize how its simulations match empirical data. We conclude with some implications of the DTC framework for basic and applied reading research.

Visualizing Live Text Streams Using Motion and Temporal Pooling

The informational context in which we live and work is becoming increasingly complex and rich, with information much more plentiful and accessible than ever before. Our informational context is also faster paced, with news and developments spreading across media and the Internet at an often astounding rate. In today's competitive world, the first response to a trend is usually the most effective. Thus far, the technology responsible for this information complexity offers little to help us quickly understand and act upon it. Although visualization is useful, its techniques are typically too slow or simply not designed to help users understand highly time-sensitive and dynamic information streams. To address this, we developed TextPool, a system that uses temporal pooling to visualize live text streams such as newswires and system telemetry. In temporal pooling, systems gather recent stream content into a buffer (pool) to use for visualization. Because the stream continues to flow through the pool in real time, the visualization must be dynamic, using motion to respond to the pool's changing content. The TextPool system processes live text streams in real time using information retrieval techniques, extracts the most frequently occurring salient terms from the buffered streams, and displays related terms next to one another in a dynamic text collage.

Preferred retinal locus and reading rate with four dynamic text presentation formats.

Electronic display devices hold the potential to improve access to written material by people with low vision. For those with central field loss, the optimal form of electronic text presentation may vary according to the location of the preferred retinal locus, but this has never been investigated. In this study, we examined the relationship between preferred retinal locus location and reading rate for four electronic display formats (rapid serial visual presentation, horizontal scroll, vertical scroll, and page). Short sentences were presented in each format to 35 low-vision (most with central field loss) and 14 age-matched control subjects. Subjects read aloud to determine maximum oral reading rate and read silently to determine preferred silent reading rate. With the exception of page format, maximum oral reading rates were faster than silent preferred reading rates for both groups of subjects. For the low-vision group, there was no significant difference in maximum oral reading rates between the four display formats; and when reading at a preferred silent rate, page format was faster than the other three formats. Though page format was read more quickly, half of the low-vision subjects preferred the horizontal-scroll format. Contrary to our predictions, there was no significant effect of preferred retinal locus location (vertical vs. lateral) on reading rate and no significant interaction between preferred retinal locus location and display format. The differences between maximum oral and preferred silent reading rates and the lack of a relationship between reading rates and preferred display format reinforce the importance of patient preference in the evaluation and selection of a device or display format during rehabilitation.

Rapid airway access

To review the steps involved in safe airway management in critically ill children. Review of articles selected through Medline until April 2003 using the following key words: intubation, children, sedation. Airway compromise is rare, but whenever it occurs, the situation depends on professionals trained to carry out safe, early, and rapid airway management, with no harm to the patient. The method currently advocated for airway management is rapid sequence intubation, which requires preparation, sedation and neuromuscular block. We observed that it is not possible to apply one single intubation protocol to all cases, since the selection of the most adequate procedure depends on indication and patient conditions. We defined the drug doses most commonly used in our setting, since little is know so far about the real effect of sedatives and analgesics. In most situations, the association of an opioid (fentanyl at 5-10 micro g/kg) with a sedative (midazolam at 0.5 mg/kg) and a neuromuscular blocking agent are sufficient for tracheal intubation. Training, knowledge, and skill in airway management are of fundamental importance for pediatric intensive caregivers and are vital for the adequate treatment of critically ill children. We present an objective and dynamic text aimed at offering a theoretical basis for the generation of new protocols, to be implemented according to the strengths and difficulties of each service.

Acesso rápido à via aérea

OBJETIVO: O artigo visa rever os passos da obtencao de uma via aerea segura no atendimento da crianca criticamente enferma. FONTES DOS DADOS: Revisao de artigos a partir da busca na base de dados Medline ate abril de 2003, utilizando os unitermos intubacao, criancas e sedacao. SINTESE DOS DADOS: O comprometimento da via aerea e incomum, porem quando ocorre, depende de profissionais treinados para a rapida obtencao da via aerea, de maneira segura, precoce e sem causar prejuizos para tais pacientes. O metodo preconizado para tal abordagem e a sequencia rapida de intubacao que alem de preparacao, utiliza sedacao e bloqueador neuromuscular. Observamos que nao e possivel a aplicacao de um protocolo unico de intubacao, pois depende da indicacao e condicoes do paciente. Definimos doses das medicacoes mais utilizadas em nosso meio, pois acreditamos que pouco se conhece do real efeito de drogas sedativas e analgesicas. Na maioria das situacoes, a associacao de um analgesico opioide (fentanil na dose de 5 a 10 µg/kg) e um sedativo (midazolam 0,5 mg/kg) e um bloqueador neuromuscular sao suficientes para a intubacao traqueal. CONCLUSOES: Treinamento, conhecimento, habilidade na obtencao da via aerea sao fundamentais para o intensivista pediatrico e sao vitais para o adequado atendimento de criancas gravemente enfermas. Apresentamos um texto objetivo e dinâmico, visando a oferecer subsidios para a geracao de protocolos a serem implementados de acordo com facilidades e dificuldades de cada servico.

Reading families: the literate lives of urban children

This dynamic text offers a rare glimpse into the literacy development of urban children and their families' role in it. Based on the author's candid interviews with her first-grade students, their parents and grandparents, this book challenges the stereotypical view that urban parents don't care about their children's education. By listening closely to the voices of her students and their families, the author helps us to move beyond negative assumptions, revealing complexities that have previously been undocumented.

Genealogical research on the Web

This is not just another resource pointing you to the thousands of genealogical research sites on the Web. Instead, this dynamic text features the tips, techniques, and resources covered in Diane Kovac's popular workshops on how to efficiently unearth an amazing array of genealogical gold on the Web. Both amateur family-history sleuths and professional geneaologists have marveled at how useful the Web can be for those with the Kovacs know-how. Included are URLs and passwords for informative Web-based activities, greatly enhancing the user-friendly quality of this book. Web forms for each activity allow you to report your progress and receive further tips from Ms. Kovacs. Learn when you'll have to travel and when you can research from home, how to involve others in your process, what resources and techniques to avoid, how to connect with experts and key libraries in the field, what tools and sites work best for the separate stages of the research process, and how to publish your own family history. Beginners, experts, librarians, and patrons - everyone has a treasure to uncover with the virtual hands-on help of Diane Kovacs!

Speeder Reader: An experiment in the future of reading

Speeder Reader is an interactive reading station built around two primary ideas: dynamic text (especially RSVP, that is, rapid serial visual presentation), and the interface metaphor of driving. As words flash one at a time on a screen in front of the reader, he or she controls the rate of speed of the words with a gas pedal (up to 1850 words per minute in the current instance). Text stream selection is performed with a steering wheel. Thus, one can “drive through a book”. We leverage people's knowledge of the familiar activity of driving an automobile (or, in the case of children, operating a speed-racing video game) to allow comfortable and intuitive access to a possibly less familiar world of interactive text. We emphasize the power and ease of the familiar driving metaphor as a navigation device. Speeder Reader was first installed at the Tech Museum of Innovation in San Jose, CA, as part of a larger exhibit on the impact of digital technologies on reading.

Designing efficient text presentation of multimedia CAI — the evaluation of dynamic text patterns and the negative repetition effect on memory

The present study investigated the effects of presenting the same material with dynamic text patterns in multimedia CAI. Four commonly used dynamic text patterns were utilized to present 10 basic concepts of mechanics. Two hundred college students selected at random from two universities were randomly assigned to one of 10 experimental conditions created by combining five text patterns (i.e. four dynamic patterns and a static presentation) and two types of repetition conditions (i.e. text presented once or three times). Their working memory capacity was assessed via a reading span test to ensure that the subjects were able to process and retain information at about the same level. Differences were found on the affective and perceptual evaluation of the dynamic text pattern. After partialing out the effect of working memory capacity, we found that, on the memory test, participants performed worse in conditions where learning material was presented three times. Interpretations and implications in designing CAI are discussed.

Dynamic texts and tourist gaze: Death, bones and buffalo

Contemporary cultural studies, including tourism research, have largely avoided analysing the effects of texts upon individuals. This gap is addressed by examining the dynamic relationships between guidebooks and tourists through interviews carried out in Tana Toraja, Indonesia. Reliance upon a limited number of international guidebooks led to a commodified experience and gaze, these sources “tutoring” tourists to gaze at aspects of Tana Toraja either comparatively, enthusiastically, or with disinterest, in order to realise an “authentic exotic” Other. A model linking the relationship between guidebooks, spoken communication, and the conceptual spheres dominating tourists’ perceptions is developed, arguing for greater recognition of the dynamism of texts in both tourism and cultural studies.

Improved Dynamic Text Indexing

In the dynamic text indexing problem, a text string has to be maintained under string insertions and deletions in order to answer on-line queries about arbitrary pattern occurrences. By means of some new techniques and data structures, we achieve improved worst-case bounds. We show that finding allpoccoccurrences of a pattern of lengthpin the current text of lengthntakesO(p+pocc+updlogp+logn) time, whereupdis the number of text uptakes performed so far; inserting or deleting a string of lengthsfrom the current text takesO(slog(s+n)) time.

Simulated cataract does not reduce the benefit of RSVP

Normally sighted younger and older (mean age 71 years) observers read sentences and random lists of words from a rapid serial visual presentation (RSVP) display and a scroll display using their normal vision and through two levels of cataract simulators. Unlike patients with central field loss (CFL), there was no decrease in the benefit of RSVP with reduced vision due to the cataract simulators. However, the usefulness of sentence-level context was reduced as visual acuity was reduced. In addition, older readers did not benefit as much from RSVP as younger readers, and many in the older group were unable to read using the more severe cataract simulators from either display format. From these data we conclude that the benefits of RSVP are not reduced with reduced acuity and contrast sensitivity, and that there are age-related changes in reading rates from dynamic text displays not related to acuity.

Dynamic suffix tree and two-dimensional texts management

This paper contains two results. First, it gives a new implementation of a dynamic suffix tree, which can manage a set of strings in a space conserving manner. Second, it presents an improved data structure for storing, searching and updating a library of two-dimensional texts. This result improves the previously best scheme, the s-trees of Giancarlo (1993), as regards the time complexity of both the search and the update operations. In particular, the search operation is as fast as that of the best static solution (which assumes the texts are fixed).

Dynamic Text Indexing under String Updates

This paper generalizes the dynamic text indexing problem, introduced in [15], to insertion and deletion of strings. The problem is to quickly answer on-line queries about the occurrences of arbitrary pattern strings in a text that may change due to insertion or deletion of strings from it. To treat strings as atomic objects, we provide new sequential techniques and related data structures, which combine the suffix tree with the naming technique used in parallel computation on strings. We also introduce a geometric interpretation of the problem of finding the occurrences of a pattern in a given substring of the text. As a result, the algorithm allows the insertion in the text of a stringSinO(|S|log(n+|S|)) amortized time, and the deletion from the text of a stringSinO(|S|logn) amortized time, wherenis the length of the current text. A pattern search requiresO(plogp+upd(logn+logp)+pocc) worst-case time, wherepis the length of the pattern andpoccis the number of its occurrences in the current text, obtained after the execution ofupdupdate operations. This solution requiresO(n2logn) space, which is not initialized.We also provide a technique to reduce the space toO(nlogn), yielding a solution that requiresO((p+upd)logplogn+pocc) query time in the worst-case,O(|S|log3/2(|S|+n)) amortized time to insert a stringSin, andO(|S|log3/2n) amortized time to delete a stringSfrom the current text.Furthermore, we use our techniques to solve the novel on-line dynamic tree matching problem that requires the on-line detection of the occurrences of an arbitrary subtree in a forest of ordered labeled trees. The forest may change due to insertion or deletion of subtrees or by renaming of some nodes. Such a problem is solved by a simple reduction to the dynamic text indexing problem.

The State of the Art in Text Filtering

This paper develops a conceptual framework for text filtering practice and research, and reviews present practice in the field. Text filtering is an information seeking process in which documents are selected from a dynamic text stream to satisfy a relatively stable and specific information need. A model of the information seeking process is introduced and specialized to define text filtering. The historical development of text filtering is then reviewed and case studies of recent work are used to highlight important design characteristics of modern text filtering systems. User modeling techniques drawn from information retrieval, recommender systems, machine learning and other fields are described. The paper concludes with observations on the present state of the art and implications for future research on text filtering.

How to implement a naturalistic model of abstracting: Four core working steps of an expert abstractor

Four working steps taken from a comprehensive empirical model of expert abstracting are studied in order to prepare an explorative implementation of a simulation model. It aims at explaining the knowledge processing activities during professional summarizing. Following the case-based and holistic strategy of qualitative empirical research, we develop the main features of the simulation system by investigating in detail a small but central test case—four working steps where an expert abstractor discovers what the paper is about and drafts the topic sentence of the abstract. Following the KADS methodology of knowledge engineering, our discussion begins with the empirical model (a conceptual model in KADS terms) and aims at a computational model which is implementable without determining the concrete implementation tools (the design model according to KADS). The envisaged solution uses a blackboard system architecture with cooperating object-oriented agents representing cognitive strategies and a dynamic text representation which borrows its conceptual relations in particular from RST (Rhetorical Structure Theory). As a result of the discussion we feel that a small simulation model of professional summarizing is feasible.