14 research outputs found
Generating Software for Well-Understood Domains
Current software development is often quite code-centric and aimed at
short-term deliverables, due to various contextual forces (such as the need for
new revenue streams from many individual buyers). We're interested in software
where different forces drive the development. \textbf{Well understood domains}
and \textbf{long-lived software} provide one such context.
A crucial observation is that software artifacts that are currently
handwritten contain considerable duplication. By using domain-specific
languages and generative techniques, we can capture the contents of many of the
artifacts of such software. Assuming an appropriate codification of domain
knowledge, we find that the resulting de-duplicated sources are shorter and
closer to the domain. Our prototype, Drasil, indicates improvements to
traceability and change management. We're also hopeful that this could lead to
long-term productivity improvements for software where these forces are at
play.Comment: 12 pages, paper accepted at EVCS 202
CADRS: A System for the Design of Complex Data Structures in LISP
This thesis describes a project to design and implement a data abstraction facility for LISP. The result of this project, the CADRS (Compiler for Access of Data Regardless of Structure) system, supports the definition, creation, and efficient manipulation of hybrid data/procedure structures that closely resemble class objects in languages like Simula [2] and Smalltalk
A Programming Environment Evaluation Methodology for Object-Oriented Systems
The object-oriented design strategy as both a problem decomposition and system development paradigm has made impressive inroads into the various areas of the computing sciences. Substantial development productivity improvements have been demonstrated in areas ranging from artificial intelligence to user interface design. However, there has been very little progress in the formal characterization of these productivity improvements and in the identification of the underlying cognitive mechanisms. The development and validation of models and metrics of this sort require large amounts of systematically-gathered structural and productivity data. There has, however, been a notable lack of systematically-gathered information on these development environments. A large part of this problem is attributable to the lack of a systematic programming environment evaluation methodology that is appropriate to the evaluation of object-oriented systems
A Simplified Faceted Approach To Information Retrieval for Reusable Software Classification
Software Reuse is widely recognized as the most promising technique presently available in reducing the cost of software production. It is the adaptation or incorporation of previously developed software components, designs or other software-related artifacts (i.e. test plans) into new software or software development regimes. Researchers and vendors are doubling their efforts and devoting their time primarily to the topic of software reuse. Most have focused on mechanisms to construct reusable software but few have focused on the problem of discovering components or designs to meet specific needs. In order for software reuse to be successful, it must be perceived to be less costly to discover a software component or related artifact to satisfy a given need than to discover one anew. As results, this study will describe a method to classify software components that meet a specified need.
Specifically, the purpose of the present research study is to provide a flexible system, comprised of a classification scheme and searcher system, entitled Guides-Search, in which processes can be retrieved by carrying out a structured dialogue with the user. The classification scheme provides both the structure of questions to be posed to the user, and the set of possible answers to each question. The model is not an attempt to replace current structures; but rather, seeks to provide a conceptual and structural method to support the improvement of software reuse methodology.
The investigation focuses on the following goals and objectives for the classification scheme and searcher system: the classification will be flexible and extensible, but usable by the Searcher; the user will not be presented with a large number of questions; the user will never be required to answer a question not known to be germane to the query
An experimental system for computer aided geometric design
technical reportThe main goal of this proposed level-of-effort project is to extend present capabilities in the area of Computer Aided Geometric Design (CAGD) and to develop custom VLSI support for some special geometric functions
Yavaa: supporting data workflows from discovery to visualization
Recent years have witness an increasing number of data silos being opened up both within organizations and to the general public: Scientists publish their raw data as supplements to articles or even standalone artifacts to enable others to verify and extend their work. Governments pass laws to open up formerly protected data treasures to improve accountability and transparency as well as to enable new business ideas based on this public good. Even companies share structured information about their products and services to advertise their use and thus increase revenue. Exploiting this wealth of information holds many challenges for users, though. Oftentimes data is provided as tables whose sheer endless rows of daunting numbers are barely accessible. InfoVis can mitigate this gap. However, offered visualization options are generally very limited and next to no support is given in applying any of them. The same holds true for data wrangling. Only very few options to adjust the data to the current needs and barely any protection are in place to prevent even the most obvious mistakes. When it comes to data from multiple providers, the situation gets even bleaker. Only recently tools emerged to search for datasets across institutional borders reasonably. Easy-to-use ways to combine these datasets are still missing, though. Finally, results generally lack proper documentation of their provenance. So even the most compelling visualizations can be called into question when their coming about remains unclear. The foundations for a vivid exchange and exploitation of open data are set, but the barrier of entry remains relatively high, especially for non-expert users. This thesis aims to lower that barrier by providing tools and assistance, reducing the amount of prior experience and skills required. It covers the whole workflow ranging from identifying proper datasets, over possible transformations, up until the export of the result in the form of suitable visualizations
An Examination of the Influence of Age on L2 Acquisition of English Sound-Symbolic Patterns
A number of researchers (DeKeyser, 2012; J. S. Johnson & Newport, 1989; Long, 1990) have argued that age is a critical factor in second language acquisition. This conclusion is based on extensive research over the last two decades that has demonstrated age-related effects in learners’ nonnativelike acquisition of phonology, morphosyntax, pragmatics, and discourse-level features of language. In the wake of such findings, there has recently been an increased interest in determining the precise linguistic areas that are difficult for adult learners and the cognitive mechanisms implicated in age-related effects. Because implicit learning plays a key role in first-language (L1) acquisition, particularly in the acquisition of statistical patterns in language, it has been proposed that age effects may be the result of attenuated implicit learning capabilities in late-teen and adult learners (DeKeyser, 2000; Janacsek, Fiser, & Nemeth, 2012). If this is true, age-related effects should be significant in linguistic areas that are not readily amenable to conscious learning processes and explicit instruction. To determine whether this is in fact the case, this study examined the linguistic knowledge of native speakers (NSs), early L2 learners, and learners who acquired English as adults. In particular, it examined these groups’ knowledge related to an area of English that is hypothesized to be difficult to learn explicitly, namely, English sound-symbolic (SS) patterns.
Participants were composed of English NSs (n = 20) and three NNS groups with L1 Korean and L2 of English. The NNS groups were divided into three groups based on age of onset (AO) , with an AO range from 3 to 9 years of age (n = 20), 10 to 16 (n = 20), and > 17 (n = 20). Three experiments were performed that tested the participants’ English magnitude SS sensitivities when forming assumptions about nonce words (Experiment 1 and 2) and their ability to utilize English SS patterns to bootstrap their learning of new vocabulary (Experiment 3). The two late L2 learner groups (AO 10-16; 17+) were found to have significantly reduced levels of SS knowledge compared to the early L2 learners (AO 3-9) and NSs in all experiments. Only in Experiment 1 and 2, the early L2 learners had diminished magnitude SS sensitivities compared to NSs, but not for Experiment 3.
Explicit and implicit aptitudes as measured by LLAMA (Meara, 2005) were also tested for potential relationships with test scores. Explicit aptitudes (LLAMA B, E, and F) did not have a significant effect on the performance of all AO groups, whereas implicit aptitude (LLAMA D) did have a moderate to strong correlation for test scores in only the two late learner groups. The early learner group was not affected by language aptitude levels during the experiments.
In sum, the study has found that there is evidence for SPE in the areas of magnitude and English phonesthemic SS patterns. Implicit language-learning aptitudes appeared to have a facilitative effect on the acquisition of these SS sensitivities for the two late L2 learner groups, but not for the early L2 learners
Simulation of packet and cell-based communication networks
This thesis investigates, using simulation techniques, the practical aspects of implementing a novel mobility protocol on the emerging Broadband Integrated Services Digital Network standard. The increasing expansion of telecommunications networks has meant that the demand for simulation has increased rapidly in recent years; but conventional simulators are slow and developments in the communications field are outstripping the ability of sequential uni-processor simulators. Newer techniques using distributed simulation on a multi-processor network are investigated in an attempt to make a cell-level simulation of a non-trivial B.-I.S.D.N. network feasible. The current state of development of the Asynchronous Transfer Mode standard, which will be used to implement a B.-I.S.D.N., is reviewed and simulation studies of the Orwell Slotted Ring protocol were made in an attempt to devise a simpler model for use in the main simulator. The mobility protocol, which uses a footprinting technique to simplify hand- offs by distributing information about a connexion to surrounding base stations, was implemented on the simulator and found to be functional after a few 'special case' scenarios had been catered for
Bibliography of synthesis documents on selected coastal ocean topics
This compilation of references to works which synthesize information on coastal topics is intended to be useful to resource managers in decision making processes. However, the utility must be understand in terms of its limited coverage. The bibliography is not inclusive of all the published materials on the topics selected.
Coverage is clearly defined in the following paragraph.
The time span of the bibliography is limited to references that were published from I983 to 1993, except for a last-minute addition of a few 1994 publications. All searches were done in mid- to late-1993. The bibliography was compiled from searches done on the following DIALOG electronic databases: Aquatic Sciences and Fisheries Abstracts, BlOSlS Previews, Dissertation Abstracts Online, Life Sciences Collection, NTlS (National Technical lnformation Service), Oceanic Abstracts, Pollution Abstracts, SciSearch, and Water Resources Abstracts. In
addition, two NOAA electronic datases were searched: the NOAA Library and lnformation Catalog and the NOAA Sea Grant Depository Database.
Synthesis of information is not an ubiquitous term used in database development. In order to locate syntheses of required coastal topics, 89 search terms were used in combinations which required 10 searches from each file. From the nearly 6,000 citations which resulted from the electronic searches, the most appropriate were selected to produce this bibliography. The document was edited and indexed using Wordperfect software. When available, an abstract has been included. Every abstract was edited.
The bibliography is subdivided into four main topics or sections: ecosystems, coastal water body conditions, natural disasters, and resource management. In the
ecosystems section, emphasis is placed on organisms in their environment on the major coastlines of the U.S. In the second section, coastal water body conditions, the environment itself is emphasized. References were found for the Alaskan coast, but none were found for Hawaii. The third section, on natural disasters, emphasizes environmental impacts resulting from natural phenomena. Guidelines, planning and management reports, modelling documents, strategic and restoration plans, and environmental economics related to sustainability are included in the fourth section, resource management. Author, geographic, and subject indices indices are provided.
The authors would like to thank Victor Omelczenko and Terry Seldon of the NOAA Sea Grant Office for access to and training on the NOAA Sea Grant Depository Database. We are grateful also to Dorothy Anderson, Philip Keavey, and Elizabeth Petersen who reviewed the draft document