177 research outputs found

    Facilitating evolution in relational database design : a procedure to evaluate and refine novice database designers' schemata : a thesis presented in partial fulfilment of the requirements for the degree of Master of Business Studies in Information Systems at Massey University

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    Relational database management systems (RDBMS) have become widely used by many industries in recent years. Latterly these systems have begun to expand their market by becoming readily available at minimal cost to most users of modern computing technology. The quality of applications developed from RDBMSs however is largely dependent upon the quality of the underlying schema. This research looks at the area of schema design and in particular schemata designed by people who have a minimal understanding of relational concepts. It uses a survey and case studies to help define some of the issues involved in the area. A procedure to modify existing schemata is described, and the schema from one of the case studies used to apply the schema re-design procedure to a real database design. The results are compared to the original schema as well as a schema designed using a conventional application of the NIAM analysis and design methodology. The research supports the hypothesis that database applications based on schemata designed by lay-persons are currently being used to support business data management requirements. The utility, reliability and longevity of these applications depend to some extent on the quality of the underlying schema and its ability to store the required data and maintain that data's integrity. The application of the schema re-design procedure presented in this thesis reveals refinements on the original schema and provides a method for lay-persons to evaluate and improve existing database designs. A number of issues and questions related to the focus of this research are raised and, although outside the scope of the research, are noted as suggestions for further work

    Changing the CIS Academic Culture: Using Senior Design Projects to Unify the Curriculum

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    Recently we initiated an effort to create a synergistic relationship between the senior design sequence and the sophomore software engineering course that resulted in a cultural change to our CIS academic community. Because of the enthusiastic response from students and faculty, we are extending this initiative to generate early interest among freshman and sophomore majors for electives in artificial intelligence and decision support. With hardware acquisitions obtained through an Instrumentation Laboratory Improvement (ILI) grant from the National Science Foundation, teams in the Senior Projects capstone sequence are preparing projects that will be employed in early courses in the curriculum. The projects will be used to provide students with insight about each of the elective areas of the curriculum through demonstrations and activities. This paper describes the five project initiatives and how the projects will be employed to generate interest in the elective areas

    The effects of feed budgeting, complete diet blending, and corn supplement blending on finishing pig growth performance in a commercial environment

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    A total of 808 pigs (PIC 337 x 1050, initially 78.4 ± 1.4 lb BW) were used to compare different feed-blending strategies for finishing pigs using the FeedPro system (Feedlogic Corp., Willmar, MN). There were 3 experimental treatments: (1) a standard-phase complete feed program, (2) blending a high- and low-lysine complete diet (curve), and (3) blending ground corn and a supplement. FeedPro is an integrated feed dispensing system that can deliver and blend 2 separate diets while dispensing. Treatment diets were fed over 4 phases (78 to 231 lb BW) with a common complete diet containing Paylean fed during the fifth phase. The 5 phases were from 78 to 115, 115 to 157, 157 to 191, 191 to 239, and 239 to 281 lb. Each treatment had 10 replicate pens and 26 to 27 pigs per pen. Overall (d 0 to 78), pigs phase-fed complete diets had greater (P < 0.01) ADG than pigs fed blended diets and tended to have greater (P < 0.07) ADG than those fed the ground corn-supplement blend. Pigs fed the blended diets had lower (P < 0.001) ADFI than pigs phase-fed complete diets or fed the corn-supplement blend. However, pigs fed blended diets had improved (P < 0.001) F/G compared to pigs phase-fed a ground corn-supplement blend and tended to have improved (P < 0.07) F/G compared to pigs fed standard-phase diets. Pigs fed standard-phase diets had heavier (P < 0.03) HCW than pigs fed the corn-supplement blend and tended to have heavier (P < 0.03) HCW than pigs fed diets on a lysine curve. However, there were no differences (P ≥ 0.11) in percentage yield, percentage lean, fat depth, or loin depth among treatments. There were no differences (P ≥ 0.11) in total revenue or income over feed costs (IOFC) across treatments. However, standard phase-fed pigs held a numerical advantage in total revenue, mainly driven by a heavier HCW over other treatments. Also, pigs fed a ground corn-supplement blend had numerically the lowest IOFC compared to other treatments. In conclusion, feeding using the FeedPro system is competitive with standard phase-fed diets on a net return basis, while feeding a ground corn-supplement blend adversely affected net returns

    Online Small-Sat Knowledge Repositories and Modeling Tools for Risk Reduction and Enhanced Mission Success

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    Developers of small satellites face the challenges of a short development schedule, incomplete information about parts from vendors, and limited budgets. The situation is complicated by the need to use commercial electronic parts rather than radiation hardened parts to meet performance and budget constraints. Fortunately, a number of organizations are standing up new modeling and data resources that are available for free online. Motivation for sharing models, part data, and lessons learned include shorter development times, increased mission success likelihood, and training the next generation of space professionals. The purpose of this paper is to make these resources and their complementary capabilities known to the small satellite community. Five free online platforms are discussed that address various parts of the information and modeling challenges posed by when electronics are operated in space, especially commercial electronics. The first platform is the Small Satellite Reliability Initiative (SSRI) Knowledge Base, a Wikipedia-like site that documents knowledge useful for successful small satellite missions. The second platform is Radiation Guidelines for Notional Threat Identification and Classification (RGENTIC), which accepts user input on electronic part types and mission parameters, then produces a list of possible radiation concerns for various part-types. The third platform is Systems Engineering Assurance and Modeling (SEAM), which incorporates architectural system modeling for identifying radiation fault propagation, Goal Structuring Notation, a visual argument scheme for creating radiation assurance cases, and construction of fault trees and Bayesian nets for reliability analysis. The fourth platform is the Parts, Materials and Processes Encyclopedia (PMPedia), a repository for information on relevant information for small satellite performance on electronic parts, material properties, and constructing processes. The fifth platform is Cosmic Ray Effects on Microelectronics (CREME), a collection of tools that enable the user to estimate the effect of the cosmic ray environment on various microelectronic parts. Taken together, these tools can significantly improve the chance of mission success

    Evaluation of feed budgeting, complete diet blending, and corn-supplement blending on finishing-pig performance

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    A total of 283 pigs (PIC TR4 x 1050, initially 77.2 ± 1.4 lb BW) were used to compare phase feeding with blending finishing diets by using the FeedPro system (Feedlogic Corporation, Willmar, MN). There were 3 experimental treatments: (1) a standard 4-phase complete feed program, (2) blending high- and low-lysine complete diets over the entire experiment, and (3) blending ground corn and a separate complete supplement within each phase. FeedPro is an integrated feed dispensing system that can deliver and blend 2 separate diets while dispensing. The 4 phases were 77 to 120, 120 to 175, 175 to 221, and 221 to 278 lb. Each treatment had 12 replicate pens and 8 pigs per pen. Overall (77 to 278 lb), ADG and ADFI were similar (P \u3e 0.24) across treatments. However, pigs fed the ground corn-supplement blend had poorer (P \u3c 0.01) F/G than pigs fed diets blended in multiple phases and tended to have poorer (P \u3c 0.09) F/G than pigs fed the standard phase diets. There were no differences (P \u3e 0.70) in HCW, percentage yield, and loin depth across treatments. Pigs fed using phase feeding of the ground corn-supplement blend had greater (P \u3c 0.02) percentage lean and lower (P \u3c 0.04) fat depth than pigs fed using phase feeding of complete diets or diet blending. There were no (P \u3e 0.28) statistical differences in total revenue and income over feed costs (IOFC) across treatments. However, the highest IOFC was obtained from diet blending, which had a numeric advantage of 1.44to1.44 to 2.32/pig over other treatments. In conclusion, the FeedPro system blended separate complete diets and a ground corn-supplement combination without adversely affecting growth performance and carcass characteristics.; Swine Day, Manhattan, KS, November 18, 201

    Connecting Mission Profiles and Radiation Vulnerability Assessment

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    Radiation vulnerability assessment early in spacecraft development is cheaper and faster than in late development phases. RGENTIC and SEAM are two software platforms that can be coupled to provide this type of early assessment. Specifically, RGENTIC is a tool that outputs descriptions of radiation risks based on a selected mission environment and the system’s electronic part portfolio, while SEAM models how radiation-induced faults in electronic parts propagate through a system. In this work, we propose a spacecraft evaluation flow where RGENTIC’s outputs, which are radiation vulnerabilities of electronic parts for a given mission, become inputs to SEAM, resulting in an automatic part-type template palette presented to users so that they can easily begin modeling the occurrence and propagation of radiation-induced faults in their spacecraft. In this context, fault propagation modeling shows how radiation effects impact the spacecraft’s electronics. The interface between these platforms can be streamlined through the creation of a SEAM global part-type library with templates based on radiation effects in part-type families such as sensors, processors, voltage regulators, and so forth. Several of the part-types defined in RGENTIC have been integrated into SEAM templates. Ultimately, all 66+ part-types from the RGENTIC look-up table will be included in the SEAM global part library. Once accomplished, the part templates can be used to populate each project-specific part library in SEAM, ensuring all RGENTIC’s part-types are represented, and the radiation effects are consistent between the two. The harmonization process between RGENTIC and SEAM begins as follows: designers input a detailed knowledge of their system and mission into RGENTIC, which then outputs a generic part-type list that associates each part-type with potential radiation concerns. The list is then downloaded in a SEAM-readable file, which SEAM uses to populate the initially blank project with the part templates that correspond to RGENTIC’s output. The final product is a system fault model using a project-specific radiation effect part library. The radiation effects considered in the part library are associated with three categories of radiation-environment issues: single event effects (SEE), total ionizing dose (TID), and displacement damage dose (DDD). An example part-type is the discrete LED, which has been functionally decomposed into input power and output light. It has a single possible radiation-induced fault that is associated with DDD, which causes degraded brightness and is observed on the output. Overall, designers will benefit from a coordination of these two tools because it simplifies the initial definition of the project in SEAM. This is especially the case for new users, since the necessary radiation models for their parts are available before modeling commences. Furthermore, starting from a duplicate of an existing project decreases the amount of time and effort required to develop project-specific models. Incorporating RGENTIC’s table of part-types resolves these issues and provides a streamlined process for creating system radiation fault models. Consequently, spacecraft designers can identify radiation problems early in the design cycle and fix them with lower cost and less effort than in later design stages

    The HIPASS Catalogue - II. Completeness, Reliability, and Parameter Accuracy

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    The HI Parkes All Sky Survey (HIPASS) is a blind extragalactic HI 21-cm emission line survey covering the whole southern sky from declination -90 to +25. The HIPASS catalogue (HICAT), containing 4315 HI-selected galaxies from the region south of declination +2, is presented in Meyer et al. (2004a, Paper I). This paper describes in detail the completeness and reliability of HICAT, which are calculated from the recovery rate of synthetic sources and follow-up observations, respectively. HICAT is found to be 99 per cent complete at a peak flux of 84 mJy and an integrated flux of 9.4 Jy km/s. The overall reliability is 95 per cent, but rises to 99 per cent for sources with peak fluxes >58 mJy or integrated flux > 8.2 Jy km/s. Expressions are derived for the uncertainties on the most important HICAT parameters: peak flux, integrated flux, velocity width, and recessional velocity. The errors on HICAT parameters are dominated by the noise in the HIPASS data, rather than by the parametrization procedure.Comment: Accepted for publication in MNRAS. 12 pages, 11 figures. Paper with higher resolution figures can be downloaded from http://hipass.aus-vo.or

    Wide-field dynamic astronomy in the near-infrared with Palomar Gattini-IR and DREAMS

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    There have been a dramatic increase in the number of optical and radio transient surveys due to astronomical transients such as gravitational waves and gamma ray bursts, however, there have been a limited number of wide-field infrared surveys due to narrow field-of-view and high cost of infrared cameras, we present two new wide-field near-infrared fully automated surveyors; Palomar Gattini-IR and the Dynamic REd All-sky Monitoring Survey (DREAMS). Palomar Gattini-IR, a 25 square degree J-band imager that begun science operations at Palomar Observatory, USA in October 2018; we report on survey strategy as well as telescope and observatory operations and will also providing initial science results. DREAMS is a 3.75 square degree wide-field imager that is planned for Siding Spring Observatory, Australia; we report on the current optical and mechanical design and plans to achieve on-sky results in 2020. DREAMS is on-track to be one of the first astronomical telescopes to use an Indium Galium Arsenide (InGaAs) detector and we report initial on-sky testing results for the selected detector package. DREAMS is also well placed to take advantage and provide near-infrared follow-up of the LSST

    Methodology for Correlating Historical Degradation Data to Radiation-Induced Degradation System Effects in Small Satellites

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    When constructing a system-level fault tree to demonstrate device-to-system level radiation degradation, reliability engineers need relevant, device-level failure probabilities to incorporate into reliability models. Deriving probabilities from testing can be expensive and time-consuming, especially if the system is complex. This methodology offers an alternative means of deriving device-level failure probabilities. It uses Bayesian analysis to establish links between historical radiation datasets and failure probabilities. A demonstration system for this methodology is provided, which is a TID response of a linear voltage regulator at 100 krad(SiO2). Data fed into the Bayesian model is derived from literature on the components found within a linear voltage regulator. An example is presented with data pertaining to the device’s bipolar junction transistor (BJT)’s gain degradation factor (GDF). Kernel density estimation is used to provide insight into the dataset’s general distribution shape. This guides the engineer into picking the appropriate distribution for device-level Bayesian analysis. Failure probabilities generated from the Bayesian analysis are incorporated into a LTspice model to derive a system failure probability (using Monte Carlo) of the regulator’s output. In our demonstration system, a 96.5% likelihood of system degradation was found in the assumed environment

    Contrasting evolutionary history, anthropogenic declines and genetic contact in the northern and southern white rhinoceros (Ceratotherium simum)

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    The white rhinoceros (Ceratotherium simum) has a discontinuous African distribution, which is limited by the extent of sub-Saharan grasslands. The southern population (SWR) declined to its lowest number around the turn of the nineteenth century, but recovered to become the world's most numerous rhinoceros. In contrast, the northern population (NWR) was common during much of the twentieth century, declining rapidly since the 1970s, and now only two post-reproductive individuals remain. Despite this species's conservation status, it lacks a genetic assessment of its demographic history. We therefore sampled 232 individuals from extant and museum sources and analysed ten microsatellite loci and the mtDNA control region. Both marker types reliably partitioned the species into SWR and NWR, with moderate nuclear genetic diversity and only three mtDNA haplotypes for the species, including historical samples. We detected ancient interglacial demographic declines in both populations. Both populations may also have been affected by recent declines associated with the colonial expansion for the SWR, and with the much earlier Bantu migrations for the NWR. Finally, we detected post-divergence secondary contact between NWR and SWR, possibly occurring as recently as the last glacial maximum. These results suggest the species was subjected to regular periods of fragmentation and low genetic diversity, which may have been replenished upon secondary contact during glacial periods. The species's current situation thus reflects prehistoric declines that were exacerbated by anthropogenic pressure associated with the rise of late Holocene technological advancement in Africa. Importantly, secondary contact suggests a potentially positive outcome for a hybrid rescue conservation strategy, although further genome-wide data are desirable to corroborate these results
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