CLiFF Notes: Research In Natural Language Processing at the University of Pennsylvania

The Computational Linguistics Feedback Forum (CLIFF) is a group of students and faculty who gather once a week to discuss the members\u27 current research. As the word feedback suggests, the group\u27s purpose is the sharing of ideas. The group also promotes interdisciplinary contacts between researchers who share an interest in Cognitive Science. There is no single theme describing the research in Natural Language Processing at Penn. There is work done in CCG, Tree adjoining grammars, intonation, statistical methods, plan inference, instruction understanding, incremental interpretation, language acquisition, syntactic parsing, causal reasoning, free word order languages, ... and many other areas. With this in mind, rather than trying to summarize the varied work currently underway here at Penn, we suggest reading the following abstracts to see how the students and faculty themselves describe their work. Their abstracts illustrate the diversity of interests among the researchers, explain the areas of common interest, and describe some very interesting work in Cognitive Science. This report is a collection of abstracts from both faculty and graduate students in Computer Science, Psychology and Linguistics. We pride ourselves on the close working relations between these groups, as we believe that the communication among the different departments and the ongoing inter-departmental research not only improves the quality of our work, but makes much of that work possible

CLiFF Notes: Research in the Language, Information and Computation Laboratory of the University of Pennsylvania

One concern of the Computer Graphics Research Lab is in simulating human task behavior and understanding why the visualization of the appearance, capabilities and performance of humans is so challenging. Our research has produced a system, called Jack, for the definition, manipulation, animation and human factors analysis of simulated human figures. Jack permits the envisionment of human motion by interactive specification and simultaneous execution of multiple constraints, and is sensitive to such issues as body shape and size, linkage, and plausible motions. Enhanced control is provided by natural behaviors such as looking, reaching, balancing, lifting, stepping, walking, grasping, and so on. Although intended for highly interactive applications, Jack is a foundation for other research. The very ubiquitousness of other people in our lives poses a tantalizing challenge to the computational modeler: people are at once the most common object around us, and yet the most structurally complex. Their everyday movements are amazingly fluid, yet demanding to reproduce, with actions driven not just mechanically by muscles and bones but also cognitively by beliefs and intentions. Our motor systems manage to learn how to make us move without leaving us the burden or pleasure of knowing how we did it. Likewise we learn how to describe the actions and behaviors of others without consciously struggling with the processes of perception, recognition, and language. Present technology lets us approach human appearance and motion through computer graphics modeling and three dimensional animation, but there is considerable distance to go before purely synthesized figures trick our senses. We seek to build computational models of human like figures which manifest animacy and convincing behavior. Towards this end, we: Create an interactive computer graphics human model; Endow it with reasonable biomechanical properties; Provide it with human like behaviors; Use this simulated figure as an agent to effect changes in its world; Describe and guide its tasks through natural language instructions. There are presently no perfect solutions to any of these problems; ultimately, however, we should be able to give our surrogate human directions that, in conjunction with suitable symbolic reasoning processes, make it appear to behave in a natural, appropriate, and intelligent fashion. Compromises will be essential, due to limits in computation, throughput of display hardware, and demands of real-time interaction, but our algorithms aim to balance the physical device constraints with carefully crafted models, general solutions, and thoughtful organization. The Jack software is built on Silicon Graphics Iris 4D workstations because those systems have 3-D graphics features that greatly aid the process of interacting with highly articulated figures such as the human body. Of course, graphics capabilities themselves do not make a usable system. Our research has therefore focused on software to make the manipulation of a simulated human figure easy for a rather specific user population: human factors design engineers or ergonomics analysts involved in visualizing and assessing human motor performance, fit, reach, view, and other physical tasks in a workplace environment. The software also happens to be quite usable by others, including graduate students and animators. The point, however, is that program design has tried to take into account a wide variety of physical problem oriented tasks, rather than just offer a computer graphics and animation tool for the already computer sophisticated or skilled animator. As an alternative to interactive specification, a simulation system allows a convenient temporal and spatial parallel programming language for behaviors. The Graphics Lab is working with the Natural Language Group to explore the possibility of using natural language instructions, such as those found in assembly or maintenance manuals, to drive the behavior of our animated human agents. (See the CLiFF note entry for the AnimNL group for details.) Even though Jack is under continual development, it has nonetheless already proved to be a substantial computational tool in analyzing human abilities in physical workplaces. It is being applied to actual problems involving space vehicle inhabitants, helicopter pilots, maintenance technicians, foot soldiers, and tractor drivers. This broad range of applications is precisely the target we intended to reach. The general capabilities embedded in Jack attempt to mirror certain aspects of human performance, rather than the specific requirements of the corresponding workplace. We view the Jack system as the basis of a virtual animated agent that can carry out tasks and instructions in a simulated 3D environment. While we have not yet fooled anyone into believing that the Jack figure is real , its behaviors are becoming more reasonable and its repertoire of actions more extensive. When interactive control becomes more labor intensive than natural language instructional control, we will have reached a significant milestone toward an intelligent agent

The Role of the English It-Cleft and the French C’est-Cleft in Research Discourse

Despite extensive work on cleft constructions, little attention has been given to their functions in specialised discourse. Using a collection of 40 research articles from the KIAP corpus, this study aims at establishing the role of clefts in English and French research discourse. The quantitative analysis reveals a higher frequency of clefts in French. The study also shows that clefts can help authors increase semantic continuity, reinforce the structure of articles and increase discursive coherence. Clefts thus facilitate the readership’s understanding of the argumentation. From a contrastive viewpoint, the study of the different authorial roles – writer, researcher, arguer, quoter, presenter – reveals that English-speaking researchers tend to be more reader-oriented than French-speaking ones. This study thus gives new insight into the way argumentation is built in research articles and paves the way for further research on the differences between French and English research discourse.Bien que beaucoup de travaux sur les constructions clivées aient été réalisés, il n’y a eu que peu d’attention portée à leur aspect fonctionnel dans le discours spécialisé. En travaillant sur un corpus de 40 articles de recherche issus du corpus KIAP, cette étude a pour but d’établir le rôle des clivées dans le discours scientifique en français et en anglais. L’analyse quantitative révèle un nombre plus élevé de clivées en français. La recherche montre également qu’elles peuvent aider les auteurs à créer une continuité sémantique, consolider la structure d’un article et augmenter la cohérence discursive. Les constructions clivées facilitent donc la compréhension de l’argumentaire par le lecteur. D’un point de vue contrastif, l’étude des différents rôles attribués à l’auteur – rédacteur, chercheur, argumentateur, référenceur, présentateur – révèle que les chercheurs anglophones ont tendance à être plus subjectifs et portés vers le lecteur que les francophones. Cet article donne donc une nouvelle vision de la manière dont l’argumentation est construite dans les articles de recherche et offre la possibilité de conduire des études plus approfondies sur les différences entre le discours scientifique en français et en anglais

CLiFF Notes: Research in the Language Information and Computation Laboratory of The University of Pennsylvania

This report takes its name from the Computational Linguistics Feedback Forum (CLIFF), an informal discussion group for students and faculty. However the scope of the research covered in this report is broader than the title might suggest; this is the yearly report of the LINC Lab, the Language, Information and Computation Laboratory of the University of Pennsylvania. It may at first be hard to see the threads that bind together the work presented here, work by faculty, graduate students and postdocs in the Computer Science, Psychology, and Linguistics Departments, and the Institute for Research in Cognitive Science. It includes prototypical Natural Language fields such as: Combinatorial Categorial Grammars, Tree Adjoining Grammars, syntactic parsing and the syntax-semantics interface; but it extends to statistical methods, plan inference, instruction understanding, intonation, causal reasoning, free word order languages, geometric reasoning, medical informatics, connectionism, and language acquisition. With 48 individual contributors and six projects represented, this is the largest LINC Lab collection to date, and the most diverse

Design of a Controlled Language for Critical Infrastructures Protection

We describe a project for the construction of controlled language for critical infrastructures protection (CIP). This project originates from the need to coordinate and categorize the communications on CIP at the European level. These communications can be physically represented by official documents, reports on incidents, informal communications and plain e-mail. We explore the application of traditional library science tools for the construction of controlled languages in order to achieve our goal. Our starting point is an analogous work done during the sixties in the field of nuclear science known as the Euratom Thesaurus.JRC.G.6-Security technology assessmen

A STUDY OF COHESION AS A TEXT-FORMING RESOURCE IN THE ACADEMIC WRITING OF SAUDI UNDERGRADUATE STUDENTS OF ENGLISH AS A FOREIGN LANGUAGE (EFL)

Assuming academic writing as a genre-specific discourse which is linguistically and socio-culturally embedded both in the wider academic discourse community and the local context where it is produced, the present study sought to investigate Saudi EFL undergraduate students' use of cohesive devices as a text-forming resource in the creation of argumentative essays. More specifically, the study attempted to explain the use of cohesion in the creation of texture, and in the rhetorical structure of the sample texts. Structured questionnaires and interviews were also used to gauge the perceptions of the teachers and the students about the teaching and learning of academic writing and cohesive devices, and to triangulate the study. The researcher adopted a mixed-methods approach for analysis of the data. Halliday and Hasan's (1976) model of cohesion analysis was the mainstay of the data analysis; however, frameworks from other perspectives such as the Systemic Functional Linguistics, English for Specific Purposes, Academic Literacies, and English Language Teaching were also consulted to find out answers to the three research questions of the study. The results obtained through quantitative and qualitative analysis of the data revealed that cohesive devices were statistically significantly correlated with the text length and sentence units. However, they varied significantly between two extremes of the text length. The appropriate use of cohesive devices was also significant as the non-significant misuse or overuse did not affect the texture or Exam/cohesion scores of the sample texts. The study also claims that cohesive density rather than the text length was the significant variable of differences in the Exam and cohesion scores for the texts. Referential and lexical cohesion appeared to be statistically significant, and thereby the most preferred cohesive devices in the corpus. The pattern of texture in the students' essays corresponded with Halliday and Hasan's (1976 p.296) notion of 'dense texture'. The study also claims to be the first initiative of its kind to have analyzed cohesion in the rhetorical structure of the argumentative essays. The move analysis revealed significant correlations between the moves in the three stages of the sample texts. The survey questionnaires unfolded statistically significant dichotomies between the pedagogic and learning beliefs of the teacher and the student participants. I argue that cohesion is an important non-structural resource in the creation of texture; however, it provides only a partial picture. The students do use cohesive devices but with instances of misuse and overuse. Moreover, there is the need to help students make use of other types of reiteration, collocations and conjunctions for a better cohesive effect, and lexical and semantic diversity. The study recommends raising awareness and functional ability of the students through explicit teaching of cohesive devices not as discrete grammatical items but as discourse semantic resources of text formation

Planning multisentential English text using communicative acts

The goal of this research is to develop explanation presentation mechanisms for knowledge based systems which enable them to define domain terminology and concepts, narrate events, elucidate plans, processes, or propositions and argue to support a claim or advocate action. This requires the development of devices which select, structure, order and then linguistically realize explanation content as coherent and cohesive English text. With the goal of identifying generic explanation presentation strategies, a wide range of naturally occurring texts were analyzed with respect to their communicative sttucture, function, content and intended effects on the reader. This motivated an integrated theory of communicative acts which characterizes text at the level of rhetorical acts (e.g., describe, define, narrate), illocutionary acts (e.g., inform, request), and locutionary acts (e.g., ask, command). Taken as a whole, the identified communicative acts characterize the structure, content and intended effects of four types of text: description, narration, exposition, argument. These text types have distinct effects such as getting the reader to know about entities, to know about events, to understand plans, processes, or propositions, or to believe propositions or want to perform actions. In addition to identifying the communicative function and effect of text at multiple levels of abstraction, this dissertation details a tripartite theory of focus of attention (discourse focus, temporal focus, and spatial focus) which constrains the planning and linguistic realization of text. To test the integrated theory of communicative acts and tripartite theory of focus of attention, a text generation system TEXPLAN (Textual EXplanation PLANner) was implemented that plans and linguistically realizes multisentential and multiparagraph explanations from knowledge based systems. The communicative acts identified during text analysis were formalized as over sixty compositional and (in some cases) recursive plan operators in the library of a hierarchical planner. Discourse, temporal, and spatial focus models were implemented to track and use attentional information to guide the organization and realization of text. Because the plan operators distinguish between the communicative function (e.g., argue for a proposition) and the expected effect (e.g., the reader believes the proposition) of communicative acts, the system is able to construct a discourse model of the structure and function of its textual responses as well as a user model of the expected effects of its responses on the reader's knowledge, beliefs, and desires. The system uses both the discourse model and user model to guide subsequent utterances. To test its generality, the system was interfaced to a variety of domain applications including a neuropsychological diagnosis system, a mission planning system, and a knowledge based mission simulator. The system produces descriptions, narrations, expositions, and arguments from these applications, thus exhibiting a broader range of rhetorical coverage than previous text generation systems

The analysis of reading tasks and texts

Bibliography : p. 78-8

IMPACTS in natural language generation NLG between technology and applications : workshop at Schloss Dagstuhl, Germany July 26-28, 2000

Instructional text, because it is a useful and relatively constrained sub-Ianguage, has been a popular target for research-oriented generation systems. This work has demonstrated that existing technology is adequate for generating draft instructions; the problem, as is typical of generation work in general, has been with the acquisition of domain and lexicogrammatical knowledge. This acquisition task is a formidable barrier to the practical use of generation technology. The Isolde project attempts to address this problem by extracting parts of the required knowledge from existing models and by building tools to tailor what is extracted into a form suitable for generation

IMPACTS in natural language generation NLG between technology and applications : workshop at Schloss Dagstuhl, Germany July 26-28, 2000

Instructional text, because it is a useful and relatively constrained sub-Ianguage, has been a popular target for research-oriented generation systems. This work has demonstrated that existing technology is adequate for generating draft instructions; the problem, as is typical of generation work in general, has been with the acquisition of domain and lexicogrammatical knowledge. This acquisition task is a formidable barrier to the practical use of generation technology. The Isolde project attempts to address this problem by extracting parts of the required knowledge from existing models and by building tools to tailor what is extracted into a form suitable for generation