bluuebunny/crossref_metadata_2025 huggingface dataset:
Positive relationships between invasive purple loosestrife (Lythrum salicaria) and plant species diversity and abundance in Minnesota wetlands
Authors: Hager Heather A , Vinebrooke Rolf D
Published: July 2004

Plant species invasions may result from, and cause, changes in the vegetation community and abiotic environment. It is often hypothesized that nonnative plant invaders suppress the diversity of native species. We examined relationships of vegetation and environmental gradients associated with the nonnative invasive wetland plant Lythrum salicaria L. to determine whether L. salicaria invasion is associated with reduced diversity and abundance of resident plant species in the wetland community. Vegetation and environmental variables were surveyed in 10 wetlands defining a gradient of L. salicaria abundance. In addition, relationships among variables were compared between invaded, Lythrum-dominated and uninvaded, Typha-dominated patches within 6 of the 10 invaded wetlands. Contrary to expectations, ordination results showed that plant diversity was higher in invaded than in uninvaded patches. Lythrum salicaria replaced other plant density and biomass on a one-to-one basis. The ordination results generated an unexpected competing set of testable hypotheses regarding whether L. salicaria invades diverse plant communities or enhances plant community diversity.Key words: invasion, Lythrum salicaria, ordination, plant community composition, Typha-dominated marshes, wetlands.
Fast- and slow-growing subalpine fir produce lesions of different sizes in response to inoculation with a blue-stain fungus associated with Dryocoetes confusus (Coleoptera: Scolytidae)
Authors: Bleiker Katherine P , Uzunovic Adnan
Published: July 2004

Trees with low vigor and reduced radial growth may be more susceptible to attack by bark beetles because of reduced host defenses. Fungi associated with bark beetles may be used to elicit an induced defense response from the host. A blue-stain fungus isolated from Dryocoetes confusus Swaine was used to examine the morphology of the hypersensitive response of fast- and slow-growing subalpine fir trees in British Columbia. Twenty fast-growing and 20 slow-growing trees were inoculated with the blue-stain isolate, and the dimensions of the resultant lesions were compared between fast- and slow-growing trees and between fungus and control treatments at 3, 7, 10, 17, and 41 d after inoculation. The length and width of the lesions was greater in response to fungus versus control treatments at 7, 10, 17, and 41 d after inoculation. The length of the lesions was significantly greater in fast- than in slow-growing trees at 7, 10, and 17 d after inoculation. There was no significant difference in the size of the lesions between fast- and slow-growing trees 41 d after inoculation. The temporary difference in the size of the lesions between fast- and slow-growing trees suggests that host vigor affects the induced defense response within a certain time frame.Key words: Abies lasiocarpa, Dryocoetes confusus, host vigor, defense, blue-stain fungi, Ophiostoma.
The roles of calmodulin polar distribution during pollen hydration and germination
Authors: Tao Wen-Jing , Liang Shu-Ping , Lu Ying-Tang
Published: July 2004

Polarity patterning of pollen germination is a vital process for angiosperm fertilization. In our study a new method was employed to investigate the real-time distribution of calmodulin (CaM) in living pollen grains and pollen tubes. The CaMGFP fusion gene was constructed under the control of the pollen-specific promoter LAT52-7 and transformed into Nicotiana tabacum L. Through confocal laser scanning microscopy, high levels of CaM were observed to accumulate in the three germinal apertures, and a tipbase gradient of CaM was detected in elongating pollen tubes. During pollen-grain hydration and germination, one of the three germinal apertures aggregated a much higher level of CaM than the other two. In addition, CaM showed a directional migration from the cytoplasm to this germinal aperture, where the pollen tube would emerge. Interestingly, CaM was not detected in the reproductive nucleus of either pollen grains or pollen tubes. Our findings indicated that the directional migration of CaM existed during pollen hydration and germination, and this movement may play a crucial role in the normal polarity establishment of pollen germination.Key words: calmodulin, polarity, pollen grain, Nicotiana tabacum.
Rock climbing alters the vegetation of limestone cliffs in the northern Swiss Jura Mountains
Authors: Müller Stefan W , Rusterholz Hans-Peter , Baur Bruno
Published: July 2004

Exposed cliffs in the northern Swiss Jura Mountains harbour a highly diverse flora with numerous endangered and relic plant species. On these cliffs, sport climbing is enjoying increasing popularity. We examined the ecological effects of sport climbing on vascular plants at the cliff base and on the cliff face by assessing plant cover and species density at various distances from frequently used climbing routes. Plant cover was significantly reduced at the base of climbing routes. Furthermore, species density (number of species per square metre) at the cliff base, as well as plant cover and species density at the cliff face, tended to increase with distance from the route. We also compared the vegetation of five frequently climbed cliffs with that of seven unclimbed cliffs. Climbing significantly altered the plant composition. Specialized rock species occurred less frequently on climbed cliffs than on unclimbed cliffs. Management plans and conservation actions are needed to preserve the threatened plant species on frequently climbed cliffs. Such plans should include the establishment of climbing-free protection areas on cliffs with a high number of specialized, relic plants and the protection of entire cliffs that are not yet climbed.Key words: disturbance, vegetation, Jura Mountains, rock climbing, limestone cliff.
Causal relationship between growth inhibition, accumulation of phenolic metabolites, and changes of UV-induced fluorescences in nitrogen-deficient barley plants
Authors: Mercure Sarah-Amélie , Daoust Benoit , Samson Guy
Published: July 2004

UV-induced chlorophyll (ChlFUV) and blue-green (BGF) fluorescences emitted by leaves have been proposed as useful indicators of plant physiological status under stress conditions. In this report, we investigated the effects of nitrogen (N) deficiency on ChlFUV and BGF emissions of leaf sections in relation to plant growth inhibition and accumulation of phenolic metabolites in barley leaves. Plants in a growth chamber were supplied with one of five different NO3 concentrations (0.8, 1.6, 5.0, 8.0, or 16 mmol/L) for a 2-week period. Total fresh biomass decreased with decreasing N supply, whereas leaf content of soluble phenolic compounds increased. This increase in leaf phenolic compounds observed with limiting N supply was accompanied by large increases of the BGF intensity and BGF/ChlFUV ratio of leaf sections and, to a lower extent, by a decrease of the leaf epidermal transmittance of UV radiation (as estimated by the ratio of ChlF intensities induced by UV and blue excitation). Interestingly, we observed a negative correlation (r2 = 0.975) between fresh biomass of plants and BGF intensity of leaf sections. By interpreting, in a context of stress physiology, the changes of UV-induced fluorescences, our results support their potential use as a sensitive tool for the rapid assessment of a plant's nutrient status.Key words: blue-green fluorescence, chlorophyll fluorescence, flavonoids, growth inhibition, nitrogen deficiency, phenolic compounds.
The eastern boreal old-growth balsam fir forest: a distinct ecosystem
Authors: Desponts Mireille , Brunet Geneviève , Bélanger Louis , Bouchard Mathieu
Published: July 2004

The objective of this project was to assess the importance of pristine forests in maintaining the botanical biodiversity of the humid boreal balsam fir forest of eastern Canada. The study was based on a comparative analysis of silviculturally mature second-growth stands and pristine forest stands at two stages of development (senescent and old growth) in the Gaspé Peninsula. The structure and composition of the stands was described, and the abundance of structural attributes evaluated. The communities of nonvascular plant species (mosses, liverworts), lichens, and saprophytic fungi were compared. The study demonstrated that the pristine forest landscape studied was composed largely of old-growth and senescent stands. Old-growth forests are differentiated by their irregular structure. The results regarding nonvascular plant species, lichens, and saprophytic fungi show higher species diversity in old-growth forests, corresponding to higher habitat diversity. Species assemblages were comparable between the pristine forests, but different from those of second-growth stands. Rare species are found more frequently in the old-growth forests. The results indicate that the old-growth balsam fir stands of the Gaspé Peninsula constitute critical habitats for maintaining a large number of species threatened by the gradual disappearance of primeval stands.Key words: forest management, biodiversity, old-growth forest, humid boreal fir forest, nonvascular plants.
Interactive effects of fertilization and throughfall exclusion on the physiological responses and whole-tree carbon uptake of mature loblolly pine
Authors: Tang Zhenmin , Sayer Mary A. Sword , Chambers Jim L , Barnett James P
Published: July 2004

Few studies have examined the combined effects of nutrition and water exclusion on the canopy physiology of mature loblolly pine (Pinus taeda L.). Understanding the impacts of forest management on plantation productivity requires extensive research on the relationship between silvicultural treatments and environmental constraints to growth. We studied the physiological responses of 18-year-old loblolly pine trees exposed to a combination of fertilization (fertilizer or no fertilizer) and throughfall (normal throughfall or throughfall exclusion). Gas exchange variables were measured in the upper and lower crown between 0900 and 1700 h from May to November in 1999. Needle fall was collected to estimate foliage mass and leaf area. Summer drought and throughfall exclusion significantly decreased predawn xylem pressure potential. Needle-level photosynthesis, transpiration, and stomatal conductance declined during the drought and were significantly lower in the throughfall exclusion treatment. Throughfall exclusion also reduced annual foliage mass and daily whole-crown photosynthesis and transpiration. In the normal throughfall treatment, fertilization had no effect on needle-level physiology, but increased annual foliage mass and whole-crown photosynthesis by 26% and 41%, respectively. With the exclusion of throughfall, however, annual foliage mass and daily whole-crown photosynthesis exhibited little response to fertilization. We conclude that greater nutrient availability enhances the carbon uptake of mature loblolly pine trees by stimulating foliage production, but the positive effects of fertilization on leaf area and carbon fixation are limited by low water availability.Key words: foliage mass, photosynthesis, Pinus taeda, seasonal trend, transpiration, xylem pressure potential.
Restauration d'images ultrasonores en contrôle non destructif
Authors: Amrani M El , Safouane A
Published: July 2004

The evolution of manufacturing techniques and the required quality show the importance of noninvasive diagnostics in industrial processes. Ultrasounds are widely used for this purpose, thanks to their innocuous character and their intrinsic qualities. In later years, the amelioration of ultrasonic techniques has required a number of improvements, including image processing. The present works focuses on the improvement of lateral resolution to optimize the localization and the size of the defects. To this end, we have developped a 3-D model that describes the propagation of ultrasonic waves and their interaction with a point defect. Reconstructing the image requires a 2-D deconvolution through an inverse filter. Tests made on Bscam images show clearly the efficiency of this technique to improve the image resolution.[Journal translation]
On a family of photon-added deformed coherent states associated with two-parameter deformed boson oscillator algebra
Authors: Naderi M H , Soltanolkotabi M , Roknizadeh R
Published: July 2004

By introducing a generalization of the (p, q)-deformed boson oscillator algebra, we establish a two-parameter deformed oscillator algebra in an infinite-dimensional subspace of the Hilbert space of a harmonic oscillator without first finite Fock states. We construct the associated coherent states, which can be interpreted as photon-added deformed states. In addition to the mathematical characteristics, the quantum statistical properties of these states are discussed in detail analytically and numerically in the context of conventional as well as deformed quantum optics. Particularly, we find that for conventional (nondeformed) photons the states may be quadrature squeezed in both cases Q = pq < 1, Q = pq > 1 and their photon number statistics exhibits a transition from sub-Poissonian to super-Poissonian for Q < 1 whereas for Q > 1 they are always sub-Poissonian. On the other hand, for deformed photons, the states are sub-Poissonian for Q > 1 and no quadrature squeezing occurs while for Q < 1 they show super-Poissonian behavior and there is a simultaneous squeezing in both field quadratures.PACS Nos.: 42.50.Ar, 03.65.w
Nonlinear instabilities in magnetized plasmas: a geometrical treatment
Authors: Dobias Peter , Samson John C
Published: July 2004

The objectives of this paper are four-fold. The first, and main concern, is the development of an alternative approach to the description of plasma physics using methods of differential geometry. These methods have long been used in many other areas of physics, such as general relativity, or quantum field theory, but do not seem to have seen extensive application in plasma physics, and in particular in magnetohydrodynamics (MHD). The second objective is to employ this formalism for perturbation calculations, particularly to nonlinear processes in MHD. The use of differential geometry for variational calculations in ideal MHD allows a self-consistent, and compact calculation of the Lagrangian, and yields results valid for arbitrary topologies of the magnetic field. The third objective is to outline the use of this formalism in analyzing several plasma processes that occur in systems with complex magnetic-field topologies. We specifically focus on the nonlinear stability of plasmas in the magnetotail-like configuration of the magnetic field, such as found in the Earth's magnetosphere. Finally, we utilize previous results to present a self-consistent method for the investigation of the nonlinear stability of magnetized plasmas and for the investigation of the transition between linear and nonlinearbehavior for systems close to equilibrium. This method is based on the analysis of potential energy density, using results for plasma displacement from a linear model to calculate the second- andthird-order energies. We demonstrate this method on an example of a force-free field with magnetic-field lines stretched from dipolar configuration. In this example, we can clearly identify the transition between linear and nonlinear instability. PACS Nos.: 52.30.g, 52.35.g
Optimized loading for particle-in-cell gyrokinetic simulations
Authors: Lewandowski J L.V
Published: July 2004

The problem of particle loading in particle-in-cell gyrokinetic simulations is addressed using a quadratic optimization algorithm. Optimized loading in configuration space dramatically reduces the short-wavelength modes in the electrostatic potential that are partly responsible for the nonconservation of total energy; further, the long-wavelength modes are resolved with good accuracy. As a result, the conservation of energy for the optimized loading is much better that the conservation of energy for the random loading. The method is valid for any geometry and can be coupled to optimization algorithms in velocity space. PACS Nos.: 52.35.Py, 52.30.Jb, 52.55.Fa
Correlativity and the origin of the T 2 difference between the BlochGrüneisen law and the Debye law
Authors: Wang Jin -Feng , Zhang Cheng -Ju , Hu Jin -Fan
Published: July 2004

To find the origin of the T 2 difference between the BlochGrüneisen law and the Debye law, a resistivity statistical model for ideal metals is presented. In the model, the system is regarded as a phonon system in which all phonons have the same momentum value, i.e., the mean momentum. The principal point of the simplified model is that the electrons located at the Fermi surface are scattered by these mean-momentum phonons. It is found that the electrical resistivity of an ideal metal is directly proportional to the phonon concentration and the square of the phonon mean momentum, which first related the electrical resistivity to the phonon parameters. The theoretical results from the model are consistent with experimental observations that the electrical resistivity is directly proportional to temperature T at high temperatures, and to T 5 at very low temperatures, naturally, this is consistent with the BlochGrüneisen law. It is found by theoretical analyses that the heat capacity of a solid at very low temperatures is only proportional to the phonon concentration. Therefore, the contribution of the square of phonon mean momentum to the electrical resistivity brings about the T 2 difference between the BlochGrüneisen law and the Debye law. PACS Nos.: 72.10.Di, 65.40.Ba
An analysis of software development environments
Authors: Prentice Dan
Published: July 2004

Software development environments are now being proposed as a way to solve problems of software development such as high costs and hidden errors. These environments have tremendous potential to structure the programming process, making it more reliable and error free. The potential also exists to ignore important costs associated with these environments. The large impact of software development environments makes them worthy of discussion. Topics of interest include 1) the package of a software development environment and 2) recurring dilemmas associated with the use of software development environments in organizations. A definition of a software development environment is provided and the dominant trends, with respect to costs, benefits and users, are discussed.
Software safety
Authors: Leveson Nancy G.
Published: July 2004

Software safety is an important aspect of software quality which is in need of research attention and priority. In this paper, software safety is defined and distinguished from reliability, and the current research efforts of the Irvine Safety Project are outlined.
The blit debugger
Authors: Cargill Thomas A.
Published: July 2004

This paper describes the evolution to date of a flexible debugger for C programs on the Blit, a multi-processing bitmap terminal. The debugger is of interest for the following reasons:

-- it is assisted by the terminal software's elegant separation of the debugger process from its subject process.

-- it resides autonomously in the terminal and is bound dynamically to arbitrary subject processes.

-- it executes asynchronously with its subject.

-- its implementation is distributed as a small process in the terminal and a large process in the host timesharing system.

-- its user interface uses graphics and a mouse.

An opinion about the most fruitful direction for further application of graphics is offered.
Rapid prototyping workshop
Authors: Squires Stephen L. , Zelkowitz Marvin , Branstad Martha
Published: July 2004

The Second Software Engineering Symposium was sponsored by ACM SIGSOFT, the IEEE Computer Society Technical Committees on Software Engineering and VLSI, and the National Bureau of Standards. Martha Branstad of the National Bureau of Standards and Marvin Zelkowitz of the University of Maryland were General Cochairmen, and Stephen L. Squires of the National Security Agency was the Program Chairman.
Operational specification as the basis for rapid prototyping
Authors: Balzer Robert M. , Goldman Neil M. , Wile David S.
Published: July 2004

This paper describes a set of freedoms which both simplify the task of specifing systems and make the resulting specification more comprehensible. These freedoms eliminate the need, in specific areas, to consider: the mechanisims for accomplishing certain capabilities, the careful coordination and integration of separate operations, the costs of those operations, and other detailed concerns which characterize implementation.These freedoms are partitioned into the areas of efficiency, method, and data, and providing them has resulted in a novel formal specification language, Gist. The main features of this language are described in terms of the freedoms it affords. An overview of the language is then presented together with an example of its use to specify the behavior of a real system.
Rapid prototyping, automatic programming, and experimental sciences
Authors: Barstow David
Published: July 2004

Automatic programming as a strategy for developing rapid prototyping systems is an attractive alternative (although perhaps further in the future) to human-oriented methodologies and to executable specifications. In the case of some experimental sciences, however, it is currently possible to develop rapid prototyping systems using the automatic programming strategy. The greatest value of such systems is gained when they are oriented toward use by domain scientists, rather than software engineers. This goal has major implications for the specification language, the user interface, and the programming knowledge required by the system.
Rapid prototyping using executable requirements specifications
Authors: Davis Alan M.
Published: July 2004

This paper describes a software tool, called the Feature Simulator, that "executes" formally written requirements specifications for real-time systems and enables users to "interact" with the simulated product at the completion of the requirements specification phase of the software life-cycle. This tool thus produces an early and rapid prototype with which customers, designers, and managers can verify that the product meets their needs and expectations. Any deficiencies that they find can then be corrected by inexpensive changes to the product's requirements specification, rather than by more costly modifications to the final product.
ACT/1
Authors: Mason R. E. A. , Carey T. T. , Benjamin A.
Published: July 2004

This paper introduces an application development methodology whereby interactive screen oriented applications are simulated in scenarios, and then prototyped. This methodology, termed "architecture-based", allows users and developers to quickly reach agreement on precise specifications of a system. The paper describes the essential features of this methodology, and relates the methodology to similar techniques proposed by others. It then describes ACT/1, a program product which is specifically designed for developing such scenarios, and for translating the specified application systems into prototypes and then into working production programs. The relationship of the methodology to some concepts discussed at the Software Engineering Symposium on Rapid Prototyping is briefly discussed.
Initial thoughts on rapid prototyping techniques
Authors: Taylor Tamara , Standish Thomas A.
Published: July 2004

This paper sets some context, raises issues, and provides our initial thinking on the characteristics of effective rapid prototyping techniques.After discussing the role rapid prototyping techniques can play in the software lifecycle, the paper looks at possible technical approaches including: heavily parameterized models, reusable software, rapid prototyping languages, prefabrication techniques for system generation, and reconfigurable test harnesses.The paper concludes that a multi-faceted approach to rapid prototyping techniques is needed if we are to address a broad range of applications successfully --- no single technical approach suffices for all potentially desirable applications.
Prototyping and small scale software projects
Authors: Strand Eugene M. , Jones Warren T.
Published: July 2004

To reduce the development time of small scale interactive software systems for research and clinical use in cardiology at UAB a display-oriented language was developed. Experience with this system has been very successful in early stabilization of the specification of the user dialogue.
An advanced operating systems project using concurrency
Authors: Leach Ronald J.
Published: July 2004

Most courses in operating systems follow one of three patterns: high level discussion with most programming done in a high level language; building operating systems from device driver level up; and courses which use emulator programs which emulate special architectures. In this paper, we describe a course which emphasizes the strong points of these approaches. The course also emphasizes teaching concurrency, introducing networking, and developing a deeper understanding of many of the system calls and system commands of the UNIX operating system. The major course project is described in the paper.
An intelligent multi-display terminal system towards
Authors: Mano Yoshihisa , Omaki Kazuhito , Torii Koji
Published: July 2004

A good programming environment should be designed after sufficient and careful considerations inclusively of the current progress of the hardware and the software. Intelligent terminals controlled by micro-processors have been developed as a certain step in this sense. But most of them are with a "single" display. It is, however, desired to compare and examine various informations during the programming process. We, therefore, have developed an intelligent terminal with "multi-displays" and implemented a system named MDPS (Multi-Display Programming System) in order to realize a high-level programming environment, where humans' activities of programming efforts are faithfully simulated.
Use of data abstraction in process specification
Authors: Bradshaw Franklyn T. , Ernst George W. , Hookway Raymond J.
Published: July 2004

Processes in computer systems are often intimately involved with various data abstractions that occur in the systems. The specification of such processes should state the nature of this involvement. This note focuses on a special kind of process, called a realization process, and its specification because it appears to capture the interplay between concurrency and abstraction in a natural way. A realization process has two important properties: it is transparent to the abstract space and it is serializable with processes at the abstract level. Transparency and serializability are the main specifications of realization processes. These concepts are illustrated by an example of the kind of realization processes found in actual computer systems which serves to motivate the discussion.
Implementation of a non-deterministic loop
Authors: Höft Hartmut
Published: July 2004

Dijkstra's calculus of guarded commands incorporates nondeterminism into the branch and the loop statements. I argue in this paper that the course CS8, Organization of Programming Languages, is an appropriate place to introduce this semantics for a language control structure into the undergraduate curriculum. In section IV I present a short implementation for the Dijkstra do... od command as a function in Mathematica. The paper concludes with the application of this function to random walks.
Pascal with internet primitives for pedagogy
Authors: Mullins Paul M.
Published: July 2004

An extension to standard Pascal which includes the kind of Internet primitives necessary to support meaningful programming projects for a networks course is described. The new language, Pascal with Internet Primitives (PIP), is a simple modification of the standard Pascal language providing interprocess communication library routines. The PIP use requests and uses networked
services
which are presented as Pascal-style files. Primitives calls are handled transparently by a compiler preprocessor and an extended run-time environment. This simple file-based extension allows the student to immediately write pedagogically useful programs using pre-planned Internet facilities. More complex assignments, such as the development of network servers, protocols, et cetera, are possible with increased awareness of primitive function calls. Increased awareness can come about gradually as a part of the course and occurs within the syntactically familiar setting of Pascal. This approach allows presentation of programming essentials as meaningful excursions, rather than as a separate topic. Design, implementation, and use of the system are described.
Software engineering and the game of monopoly
Authors: Toal Raymond J. , Dorin Philip M.
Published: July 2004

We claim that a good basis for a course in Software Engineering is to have a group of students make a computer program for the game of Monopoly. We discuss our experiences in organizing and running such a course, and on the computer program that resulted from the most recent version of the course.
Group projects in software engineering at York
Authors: Briggs Jim
Published: July 2004

This paper describes the format of the second year group project in software engineering undertaken by all single-subject undergraduate students in Computer Science at the University of York.
OPIUM: a debugging environment for Prolog development and debugging research
Authors: Ducassé Mireille , Emde Anna-Maria
Published: July 2004

Opium is an extensible debugging environment for PROLOG providing high-level debugging facilities for programmers and debugging experts.
Ada task taxonomy support for concurrent programming
Authors: Lai Robert Chi Tau
Published: July 2004

The Ada task taxonomy can be used as the main scheme to help programmers to develop concurrent programs. The conventional way of defining a taxonomy for software modules is not based on the interactive behavior of the modules. The behavior of Ada tasks is more dynamic than that of other Ada modules such as procedures, functions and packages. By classifying sets of tasks by their interactive characteristics, functions, and procedural behaviors, a task taxonomy can be formulated. Task taxonomy can be used as an abstraction for software developers to design, store, and retrieve concurrent systems and reusable parts. A set of tools based on characteristics formally representing kinds of tasks can be designed. This set of tools will help programmers define their own task taxonomies for designing, constructing, and maintaining concurrent systems.
A conceptual model for megaprogramming
Authors: Tracz Will
Published: July 2004

"
Currently, software is put together one statement at a time. What we need is to put software together one component at a time
." --- Barry Boehm, at the Domain Specific Software Architecture (DSSA) Workshop, July 11--12, 1990.Megaprogramming, as defined at the first ISTO Software Technology Community Meeting, June 27-29, 1990, by Barry Boehm, director of DARPA/ISTO, is component-based software engineering and life-cycle management. The goal of this paper is to place megaprogramming in perspective with research in other areas of software engineering (i.e., formal methods and rapid prototyping) and to describe the author's experience developing a system to support megaprogramming.The paper, first, analyzes megaprogramming and its relationship to other DARPA research initiatives (CPS/CPL --- Common Prototyping System/Common Prototyping Language, DSSA --- Domain Specific Software Architectures, and SWU --- Software Understanding). Next, the desirable attributes of megaprogramming software components are identified and a software development model (The 3C Model) and resulting prototype megaprogramming system (LILEANNA --- Library Interconnection Language Extended by Annotated Ada) are described.
Estimating the total number of software failures using an exponential model
Authors: Musa John D. , Iannino A.
Published: July 2004

Different approaches to estimating the total number of failures parameter for the Jelinski-Moranda model are considered. The maximum likelihood estimator, a harmonic jackknife maximum likelihood estimator, and a simple Bayesian estimator are studied. None of these is found to be entirely satisfactory, each suffering from either infinite estimates and/or severe bias in small to moderate samples. The purpose of this paper is to summarize this work, in order to stimulate a search for better estimators.
Coding quality and tools in programming methods
Authors: Perlman G
Published: July 2004

Twenty-two programming tools were introduced in coordinated exercises as part of a programming methods course. Twenty-two or twenty-four graduate students with work experience responded to a survey asking about previous and intended use of the tools. The survey showed that many tools were new and useful to the students. My conclusion is that it is worthwhile to incorporate a module on coding quality and tools in software engineering programs.
An approach for assessing software prototypes
Authors: Church VE , Card D N , Agresti W W , Jordan Q L
Published: July 2004

A procedure for evaluating a software prototype is presented. The need to assess the prototype itself arises from the use of prototyping to demonstrate the feasibility of a design or development strategy. The assessment procedure can also be of use in deciding whether to evolve a prototype into a complete system. The procedure consists of identifying evaluation criteria, defining alternative design approaches, and ranking the alternatives according to the criteria.
This is IT: a metamodel of the software process
Authors: Wileden J
Published: July 2004

A systematic study of the software process will require a vocabulary in which various process models, methods and approaches can be described, compared and contrasted. This paper describes a meta-model that might provide such a vocabulary, illustrates how it might be used, and poses some example questions of the kind that such a meta-model should help in answering.
Software development methodologies and traditional and modern information systems
Authors: Connors Danny T.
Published: July 2004

Considerable discussion exists about the proper methodology for developing software. Some individuals favor a strict step-by-step approach, while others favor rapid prototyping. The extra dimensions of newer information systems such as Decision Support Systems and Expert Systems add to the confusion. Many individuals believe that new systems need new methodologies.This paper surveys the literature to determine current philosophies concerning traditional and modern information systems. Then, a typology which integrates the philosophies into a model useful for selecting an appropriate methodology for the information system task at hand is proposed.
A first computing course based on curricula 1991
Authors: Alvarez Rubio Juan
Published: July 2004

A two semester first year course is proposed that provides an introduction to algorithmic problem solving and programming, human-computer communication, file and database systems, and software engineering. The goals of this course coincide and expand upon the
Introduction to Programming and Computer Tools
course proposed by the ACM Task Force as a prerequisite for studies in computer science. The methodology integrates the contents of several knowledge units of the
Computing Curricula 1991
of the ACM/IEEE-CS.
Teaching concurrency with Joyce and Linda
Authors: McDonald Chris
Published: July 2004

To overcome the difficulty of demonstrating the principles of concurrency with limited parallel computing resources, a concurrent programming language has been designed and implemented which uses the Linda parallel programming paradigm. The language executes under the UNIX operating system and is supported by an X-windows based viewer of programs undergoing concurrent execution. This paper describes the language, its compiler and execution environment and experiences gained in using the language in a third year undergraduate course over the last two years.
Developing expertise in expert system development by developing prototypes for actual commercial applications
Authors: Mazlack Lawrence J. , Pick Roger A. , Tudor Paul , Wood Wallace R.
Published: July 2004

We designed and executed a course to develop expert system expertise in a classroom environment. It taught both the theory and practice of knowledge-based systems. Teams consisted of knowledge domain experts and computer experienced people. The interest was training people in knowledge-base tasks and having them develop commercially significant projects. The focust of this paper is on what was done in the classroom to provide a significant expert system development experience.
Good pedagogical random number generators
Authors: Warford J. S.
Published: July 2004

A
CACM
by Park and Miller [6] advocated a standard for random number generators based on the Lehmer generator [5] and criticised a number of computer science textbooks for presenting bad random number generators. This paper advocates the proposed standard and presents a set of generators based on theoretically sound principles that are also useful for microcomputer implementation and classroom presentations at the introductory level.
Introducing functional programming in discrete mathematics
Authors: Wainwright Roger L.
Published: July 2004

Programming assignments in my discrete mathematics course have changed recently due to an influx of non-computer science students with little or no programming experience. Programming problems are now assigned in a simple to learn, easy to write, mathematical-like functional programming language that requires no previous programming experience. In theory, all students begin on the same basis. Exposure to the concepts of functional programming is an essential part of computer science and mathematics curricula. For most students this is the only exposure to functional programming. Functional programming and discrete mathematics are a natural combination. One week of lectures and perhaps a small monetary investment is all that is required. An instructor totally unfamiliar with functional programming can easily learn enough in a week or so to present a simple introduction to the topic. Introducing functional programming concepts in discrete mathematics was very successful. Students found the exposure to functional programming to be an insight they had never experienced before and enthusiastically recommended an introduction to functional programming be a permanent part of the course.
Experience with the language SR in an undergraduate operating systems course
Authors: Hartley Stephen J.
Published: July 2004

In undergraduate operating systems classes, students learn about concurrent process synchronization, including such things as shared data, race conditions, critical sections, mutual exclusion, semaphores, monitors, and the test-and-set hardware instruction. They also study interprocess communication, message passing, rendezvous, and remote procedure calls. Solutions to classical problems, such as the dining philosophers, producers and consumers, bounded buffers, and readers and writers, are presented using the above concepts. However, students need to write programs in a language that provides facilities for concurrent programming in order to appreciate fully the above concepts. This paper describes the SR language and discusses its successful use as an environment for concurrent programming in an undergraduate operating systems class.
Results of SIGCSE membership survey
Authors: Dale Nell
Published: July 2004

SIGCSE is alive and well, as evidenced by the fact that 445 of you took the time to fill out the six-page questionnaire mailed out to the approximately 2600 SIGCSE members in early January. Those of you who were at the Technical Symposium in Kansas City heard me summarize the responses. Here is a hard copy of the results, including additional responses received after the Symposium. I will group the responses into three categories:
Who are we? How do we rate current services
? and
Where should we be going
? In closing, I will discuss comments from the free response section of the questionnaire and pose a challange to educational researchers.
Teaching C with UNIX for college credit to professional programmers
Authors: Osborne Lawrence
Published: July 2004

This paper addresses the problem of introducing the UNIX operating system and the C language to professional programmers and system analyists who have had little or no experience with either UNIX or C. Workshops given to industrial employees ordinarily last for no more than a few consecutive days and offer no college credit. In contrast, the course described in this paper required approximately nine days, spread over a three week period, and the students earned three hours of undergraduate credit towards a degree in computer science. A detailed breakdown of the contents of the lectures is given, and examples of the programming exercises done in the laboratory component of the course are presented. Observations on the effectiveness of the approach and suggestions for future improvements in the course are offered in the final section of the paper.
Identifying foundations of software engineering expertise
Authors: Rösel Andreas , Bailes Paul
Published: July 2004

The importance of software development expertise to our society and likewise the importance of education in this field are self-evident. At the same time it is undisputed that software development at the professional level is a complex activity. It must be presumed that the make-up of expertise required to successfully complete such activities will itself be non-simple, deserving of our attention. A hierarchical view of professional expertise is presented and a method for determining the fundamental principles making up lasting expertise is systematically derived. The method is applied to determine principles of software engineering expertise. The view presented provides a step towards a well founded understanding of the types of expertise needed for the activity of software development. Educators involved in courses releasing professionally recognised software developers should be interested to examine which aspects of the expertise-derivation they already utilise and which aspects could further benefit their courses.
A discussion on the Ada Run-Time Environment in safety critical applications
Authors: Chelini James V.
Published: July 2004

The complex systems being built today are increasingly software driven. These systems, such as air traffic control systems, nuclear power plants, avionics software, and even automotive control software, are integral parts of our world. We take these systems for granted everyday and trust them to work safely, without injury to us.The Ada language is being used in a growing number of these systems. This requires a reevaluation of how the language can be effectively used in safety-critical systems. A key element of this evaluation is the Ada Run-Time Environment (RTE) itself. Ada is unique in that it provides its own real-time executive. This paper examines the impact of the Ada RTE on safety critical software and discusses steps to identify and reduce potential risks.
An operating systems project
Authors: Goh Angela
Published: July 2004

An operating systems project which is part of an introductory course in operating systems is described. The project, which emphasizes on process management within operating systems, was implemented on the Motorola 68000 Single Computer Board. In order to complete the work, the students were required to integrate knowledge gained from other courses.
Student designed machines for a theory of computation course
Authors: Krone Joan
Published: July 2004

Most Computer Science faculty members look forward to teaching a course in Theory of Computation. However, there is usually concern over how well students are able to understand Turing's thesis, Church's thesis, and the relationship between them with only one semester of concentration on details of a particular textbook. This paper describes how students in the Theory of Computation Course at Denison University designed their own theoretic machines and showed how those machines could be used to solve example problems, hopefully achieving an understanding of the theses by Church and Turing as a result of developing the technical details necessary in describing their machines.
Real theorem provers deserve real user-interfaces
Authors: Théry Laurent , Bertot Yves , Kahn Gilles
Published: July 2004

This paper explains how to add a modern user interface to existing theorem provers, using principles and tools designed for programming environments.
The use of Logo in an introductory computer science course
Authors: Shaffer Dale
Published: July 2004

The use of LOGO as a first language in Computer Science is examined and compared to the use of Applesoft BASIC. The method for demonstrating LOGO's adequacy is based on comparisons with ACM's CS1 model.
Software engineering practicums: a case study of a senior capstone sequence
Authors: Oman Paul W
Published: July 2004

Increasing demand for software engineers has caused academia to search for means to incorporate software engineering into the existing computer science curriculum. This paper explores traditional software engineering instructional methods and then provides a case study of a two semester practicum modeled after specialized training programs. These practicums, integrated into the University of Idaho Computer Science program, require all computer science seniors to solve "real-world" software engineering problems for actual customers. The practicums serve as quality control exit requirements to ensure that computer science graduates have the software engineering skills required in industry and graduate school. The integrated nature of the computer science program uniquely provides experiential variety while fostering individual responsibility, group interaction skills, and practical experience.
A first course in computer science for small four year CS programs
Authors: Bryant Robert , De Palma Paul
Published: July 2004

The paper is a contribution to the ongoing debate over the content of CS1. Instead of opting for either the depth first or breadth-first approach, we have built a course using some of the strongest elements of each. This course does not replace CS1 in our department. Rather, we use it to give beginning computer science students a more balanced view of the discipline than CS1 does. We also use it to teach in one place much of the redundant material found in the standard computer science curriculum. We find this makes for more sophisticated students and lets us use our small faculty more efficiently.
A set of programming projects for a second programming course
Authors: Chandra Kailash
Published: July 2004

A set of six related programming projects are presented. These projects are based on the assignments given to a class taking a second course in Pascal programming. The first project started with a source code of a working program assigned to the students giving them a jump start and then taking them step by step to a project where they developed a simple full-screen visual text editor. It has been a very successful experiment. It is hoped that the others can use similar programming assignments in their classes.