Harriet J. Fell

Analysis of a Public Key Approach Based on Polynomial Substitution

We set out to build a public key cryptosystem by repeatedly substituting for variables in multivariate polynomials and simplifying the results to conceal the substitution process. There seems, however, to be no way to build such a system that is both secure and has a public key of practical size when the devices used to limit the number of coefficeints are nilpotence and J-rings. We have only shown, however, that it is impossible to produce such a system if the total degree of the encryption polynomial determines the size of the public key. Perhaps, by properly choosing p 0 and p 1, we can employ the fundamental scheme to produce sparse encrypting polynomials. Then the public key could be kept small while the encrypting polynomial bas large total degree and is difficult to invert.

Exploring Martian planetary images: C++ exercises for CS1

We present a series of programming exercises based on photographic images of Mars collected by the NASA Viking Orbiter. Even without the news that there may once have been life on Mars [1], we feel that these exercises provide an exciting platform for exploring machine representation of data, presentation of data, and methods of storing and extracting data from files. All exercises are on the level easily mastered in the first programming course.

Foundations of computer science: what are they and how do we teach them?

Computer science as a discipline is changing rapidly. New developments in software and hardware are changing the way we write programs, design systems, and create applications. The role of the first year curriculum in computer science is to lay the foundations for becoming a professional in the field. We examine the ways in which the changing nature of computer science influences our teaching methods, our view of which concepts are fundamental, and the overall sense of what it takes to become a successful computer scientist. We propose a first year curriculum model that has a strong emphasis on design, on programming in a structured project based environment, and on the extensive use of tools, libraries, and templates. We illustrate this model by describing a collection of graphicsbased exercises that apply computing across the disciplines. 1 Curriculum trends in computer science 1.1 Depth first versus breadth first Unlike mathematics where the freshman curriculum has consisted of calculus for generations, there is a significant debate among computer science educators about what to teach to freshman computer science majors. The two main views have been described as ‘breadth first’ and ‘depth first’ ACM/IEEE Curriculum 91 [21]. The proponents of the ‘breadth first’ view recommend that students receive a broad introduction to computer science including topics such as algorithmic, logic, computer architecture, machine languages, high level languages, compilation, the elements of programming, artificial intelligence, etc. The proponents of the ‘depth first’ view recommend that programming be the focal topic for the freshman year and that related topics such as algorithms, data structures, and design be motivated as providing a more powerful perspective on the programming process. Both views have merit which is why the debate has not and probably cannot be entirely resolved. At Northeastern University, we organize the freshman program on the ‘depth first’ model. We do this from a belief that what brings a student into computer science in the first place is the fact that a computer program designed from pure thought can make the computer do wonderful things. We want to build on Permission to tnal(e Cfigitalmarcl mpy of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or mmmercial advantage, the copyright notice, the title of the ublication and its date appear, and notice is given that ! copying is y permission of ACM, Inc. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission andlor a fee. Integrating Tech. into C.S.E. W96 Barcelona, Spain 01996 ACM O-89791 -844-u9WOO09...

visiBabble for reinforcement of early vocalization

505O this excitement. We also have a practical reason. After the freshman year, our students follow a cooperative education plan in which they alternate academic work with work in industry every three months. It is only by following a ‘depth first’ model that we can prepare our students to be ready for their first job assignments in the software industry. 1.2 The importance of design The rapid developments in both hardware and software that have taken place in the past few years call into question the traditional approaches to computer science education for undergraduates. In 1976, Niklaus Wirth could summarize the essence of software design in the title of his book Algorithms + Data Structures = Programs. The philosophy of this text is that a knowledge of the classic algorithms and data structures is the critical component in the education of a computer scientist. The development of complete programs is seen as a relatively simple top-down process in which the functional decomposition of a design problem leads naturally to the use of appropriate algorithms and data structures. Today, the design and development of programs is more complex and more subtle than the simple model suggested by Wirth’s title. To train students to work in a modern software development environment, it is essential to recognize that classic algorithms and data structures are just the starting point. The design process itself must be a major focus throughout the curriculum. Traditionally, computer science education has been most concerned with the design and performance of individual algorithms on individual data structures. It is now imperative that the design of large program structures with elaborate functionalities and elegant interfaces be treated as one of the central problems of computer science education. To build an innovative curriculum with a focus on issues of design, it is important to recognize certain critical realities: . The object-oriented paradigm has become central to the design process [2, 10, 16]. The concept of object combines a data structure with the algorithms that operate on it. Although this combination may at first seem merely convenient, it changes the entire design process from a top-down functional model to a model of objects that interact with one another. The bells and whistles of object-oriented design such as inheritance, function and operator overloading, and templates also make the use of objects more natural and more powerful than classic data structures. . Graphics and user interface design are now as fundamental to programming as text [1,5,6,9,10,13,14, 18,19]. Due to the needs of graphics and user interface design, modern operating

Automatic babble recognition for early detection of speech related disorders

The visiBabble system processes infant vocalizations in real-time. It responds to the infants syllable-like productions with brightly colored animations and records the acoustic-phonetic analysis. The system reinforces the production of syllabic utterances that are associated with later language and cognitive development. We report here on the development of the visiBabble prototype and field-testing of the system.

Baby-Babble-Blanket: infant interface with automatic data collection

We have developed a program, the Early Vocalization Analyzer (EVA), that analyses digitized recordings of infant vocalizations. The purpose of such a system is to automatically and reliably screen infants who may be at risk for later communication problems. EVA applies the landmark detection theory of Stevens et al., for the recognition of acoustic features in adult speech, to detect syllables in vocalizations produced by typically developing six to thirteen month old infants. We discuss the differences between adult-specific code and code written to analyse infant vocalizations. In a validity test, EVA achieved 90% agreement in marking 128 landmarks commonly identified by two human judges, was often closer to one or both judges than the humans were to each other. In a second test EVA and a human judge had 86% agreement in identifying 150 landmarks.

Using the Baby-Babble-Blanket for infants with motor problems: an empirical study

The Baby-Babble-Blanket (BBB), a pad with pressure-sensitive switches linked to a Macintosh computer, was developed to provide infants or developmentally delayed children with a communication/environmental control system. Lying on the pad, infants use early movements, such as head rolling or leg raising, to produce digitized sound. The BBB software automatically collects data on the overall number of switch activations and on particular switches in a variety of conditions and graphs them. Possible important uses of the BBB are to train cause-effect skills, to increase the overall amount of movement, or to encourage particular movements. Preliminary data were collected on a 5-month-old infant with club feet, hydrocephaly, and poor muscle tone to determine what movements the infant could use to access the pad, and whether the use of particular body parts could be increased by the ability to access the digitized mothers voice. Results suggest that the infant could activate the device by two different moveme...

Comparing emotions using acoustics and human perceptual dimensions

Children with motor problems often develop to be passive, presumably because of an inability to communicate and to control the environment. The Baby-Babble-Blanket (BBB), a pad with pressure switches linked to a Macintosh computer, was developed to meet this need. Lying on the pad, infants use head-rolling, leg-lifting and kicking to produce digitized sound. Data is collected by the BBB software on the infants switch activations. An empirical study was carried out on a five-month-old infant with club feet, hydrocephaly and poor muscle tone to determine what movements the infant could use to access the pad, whether movements would increase over a baseline in response to sound, and what level of cause and effect the infant would demonstrate. Videotapes and switch activation data suggest that the infant: 1) could activate the device by rolling his head and raising his legs. 2) increased switch activations, over a no-sound baseline, in response to the sound of his mothers voice. 3) was able to change from using his head to raising his legs in response to the reinforcer.

Scaling: a design pattern in introductory computer science courses

Understanding the difference between emotions based on acoustic features is important for computer recognition and classification of emotions. We conducted a study of human perception of six emotions based on three perceptual dimensions and compared the human classification with machine classification based on many acoustic parameters. Results show that the six emotions cluster differently according to acoustic features and to perceptual dimensions. Acoustic features fail to characterize the perceptual dimension of valence. More research is needed to find acoustic features that have a close relation to human perception.

EVA, an early vocalization analyzer: an empirical validity study of computer categorization

We present a series of programming exercises that use scaling as a theme for teaching design techniques in the introductory computer science course sequence. All exercises are on the level easily mastered in the first year of programming. Additionally, the exercises introduce a rich variety of applications of computer science.