2,299 results for Report

  • Comparing Hash Function Algorithms for the IPv6 Flow Label

    Anderson, Lewis; Brownlee, John; Carpenter, Brian (2012)

    Report
    The University of Auckland Library

    We compare several stateless hash algorithms for generating IPv6 flow labels, by testing them against trace files of IPv6 traffic measured at four different sites. The criteria for comparison were uniformity of the resulting distribution of hash values and computing time. Of the algorithms tested, we recommend FNV1a-32. We also note how the hash values may be made hard for a third party to predict.

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  • Quasi Convolutional Smoothing of Polyhedra

    Lobb, R.J. (1995-05)

    Report
    The University of Auckland Library

    This paper describes a system for the representation and rendering of polyhedral scenes in which individual components can have different user-specified amounts of rounding applied to edges and corners. Objects are represented by structures similar to CSG trees but with arithmetic operators at internal nodes rather than set membership operators. An object’s smoothing attribute specifies the radius of a spherical smoothing filter, and the smoothed object’s surface is defined by an iso-density surface after low-pass filtering. The filtering is an approximation to true convolutional filtering, but allows rapid determination of iso-density surfaces. The rounded surfaces are similar to those achieved by use of filleting and surface blending techniques during modelling, but are much easier to specify, far more economical in storage, and simpler to compute. By varying the smoothing radii, a wide range of effects can be obtained, from near-perfect polyhedra through to “blobby models”.

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  • From Serial to Massively Parallel Constraint Satisfaction

    Guesgen, H.W. (1993-03)

    Report
    The University of Auckland Library

    Local propagation algorithms such as Waltz filtering and Mackworth’s AC-x algorithms have been successfully applied in AI for solving constraint satisfaction problems (CSPs). It has been shown that they can be implemented in parallel very easily. However, algorithms like Waltz filtering and AC-x are not complete. In general, they can only be used as preprocessing methods as they do not compute a globally consistent solution for a CSP; they result in local consistency also known as arc consistency. In this paper, we introduce extensions of local constraint propagation to overcome this drawback, i.e. to compute globally consistent solutions for a CSP. The idea is to associate additional information with the values during the propagation process so that global relationships among the values are maintained. The result are algorithms that are complete and for which there are straightforward, parallel and massively parallel implementations.

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  • Efficient Parallel Algorithm for Tree Accumulations

    Gibbons, J.; Cai, W.; Skillicorn, D. (1993-03)

    Report
    The University of Auckland Library

    Accumulations are higher-order operations on structured objects: they leave the shape of an object unchanged, but replace elements of that object with accumulated information about other elements. Upwards and downwards accumulations on trees are two such operations; they form the basis of many tree algorithms. We present two Erew Pram algorithms for computing accumulations on trees taking O(log n ) time on O (n/log n) processors, which is optional.

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  • Multi-Methods in a Statically-Typed Programming Language

    Mugridge, R.B.; Hamer, J.; Hosking, J.G. (1991-11)

    Report
    The University of Auckland Library

    Multivariant functions in Kea are a statically-typed form of the multi-methods of CLOS (Keene, 1989) but encapsulation is retained. Multivariants permit fine typing distinctions to be made, allow despatching to be avoided in some cases, and may be used to avoid some restrictions of the contravariance rule. Once multivariant functions are introduced by example, the semantics of the despatch of multivariants are provided, based on the generation of despatching variants. Three issues arise with despatching: redundancy, ambiguity, and exhaustiveness of a (partially-ordered) set of variants with respect to a function call. It is shown that the approach taken here is consistent with separate compilation.

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  • A New Structure for an Operating Systems Course

    Creak, G.A.; Sheehan, Robert (1998-03)

    Report
    The University of Auckland Library

    This report has grown from a seminar which we presented to the Auckland University Computer Science Department in 1995. Though blandly entitled "An Operating Systems Course", it was in fact an account of changes which we had made in the nature of the department's final undergraduate year operating systems course since Alan took charge of it in 1985. Robert joined in 1988 while Alan was on leave; since 1989, we have presented the course jointly except during Alan's further leave in 1996. -- from Introduction.

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  • Rewriting History: More Power to Creative People

    Lutteroth, Christof; Weber, Gerald (2011)

    Report
    The University of Auckland Library

    Trying out different alternatives is a natural part of creative work. However, with the current tools we often end up having to redo changes that worked in one alternative on other versions. This is additional work that should be unnecessary in our electronic age. We propose a new approach for supporting creative work: an artifact is described as the history of the operations that created it. We show that by allowing users to change the history, the common use cases of merging, generalizing and specializing can be supported efficiently. The “rewriting history” approach is based on a formal specification of the operations offered by a tool, and enables exciting new ways to share and combine creative work. It is complementary to state-based version control and offers the user a new understanding of merging. It was implemented for a drawing tool that supports synchronous collaborative work.

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  • Tuple Space for Mashups

    Lutteroth, Christof; Tian, Sheng; Weber, Gerald (2011)

    Report
    The University of Auckland Library

    Inter-widget communication is essential for enterprise mashup applications. To implement it, current mashups use the publish/subscribe pattern. However, for mashup scenarios with many interactions between widgets, this pattern requires a lot of manual wiring between the widgets in existing mashup platforms. In this paper, we propose a new event model, UWEM, which is an extension of Linda and Tuple Space. UWEM separates event publishers and subscribers in space, time and reference. It provides a more flexible and effective interaction pattern among widgets. It makes it easier for users to build mashups, and also delivers a plug and play experience of building mashup application for users. We have implemented UWEM in a popular enterprise mashup framework.

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  • Logic Blog 2010

    Nies, Andre; Bienvenu; Khalimulin (2010)

    Report
    The University of Auckland Library

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  • Image Flow in Light Fields

    van der Linden, Jarno (1999-08)

    Report
    The University of Auckland Library

    Image-based modeling can simplify the scene modeling process in computer graphics by assuming that it is not the geometry of a scene that is of interest, but rather the look of a scene. Instead of obtaining detailed surface geometry and colour data, visual data alone is acquired. This can be done with relative ease through photography. Light Fields are a recent development in how such information is stored. Images of a scene are used to create a four dimensional radiance function. A light field determines what a scene looks like when viewed from anywhere outside of the space enclosing the scene. With light fields, as in many other image-based modeling and rendering systems, there is a trade-off between quality and memory. A high quality result requires storage of a large number of samples obtained from high-resolution input images. The number of images required can be reduced by using image warping techniques based on image flow. Image warping computes intermediate images from the existing images in the system, thereby giving the illusion of a higher sampling density than that actually used during acquisition. In this paper, we show how to use image flow in light fields to produce high quality output from only a small set of input images. Unlike previous work, we do not generate intermediate images, but rather use image flow to render a new view directly. High quality new views can be generated from as few as 8x8 images. We demonstrate several rendering methods for image-flow augmented light fields

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  • Logic Blog 2011

    Nies, Andre (2011)

    Report
    The University of Auckland Library

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  • The Feasibility and Use of a Minor Containment Algorithm

    Xiong, Liu; Dinneen, Michael (2000-02)

    Report
    The University of Auckland Library

    We present a general algorithm for checking whether one graph is a minor of another. Although this algorithm is not polynomial-time, it is quite practical for small graphs. For all connected graphs with 5 vertices or less we count how many connected graphs of order at most 9 are above them in the minor order. Our computed tables may be useful in the design of heuristic algorithms for minor closed families of graphs.

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  • When Virtual Memory Isn't Enough

    Thomborson, C. (1996-11)

    Report
    The University of Auckland Library

    Virtual memory, even on the largest and fastest contemporary computers, is neither large enough nor fast enough for all applications. Some data structures must be held in the file system, and some ‘performance hints’ must be given to the memory-management runtime routines. For these reasons, most large-memory application codes are littered with system-specific names, constants, file-migration policies, pragmas and hints. Such codes are very difficult to develop, maintain, and port. I propose a new paradigm for the design of large-memory codes, providing many of the performance advantages and few of the drawbacks of system-specific coding techniques. In my paradigm, programmers must organise their data structures into a series of (nesting) data blocks, with blocksizes Bh increasing in a fractal (power-law) progression [see formula in pdf]. Furthermore, the larger blocks must be referenced much less frequently than the smaller blocks. I argue that efficient algorithms for several important problems on workstations and PCs are found at ∂≈3/2 and R=8. I sketch a model of memory performance that explains why non-hierarchical large-memory codes require system-specific tuning for efficient execution.

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  • Punctured Elias Codes for Variable-Length Coding of the Integers

    Fenwick, P. (1996-12)

    Report
    The University of Auckland Library

    The compact representation of integers is an important problem in areas such as data compression, especially where there is a nearly monotonic decrease in the likelihood of larger integers. While many different representations have been described, it is not always clear in which circumstances a particular code is to be preferred. This report introduces a variant of the Elias γ code which is shown to be better than other codes for some distributions.

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  • Deriving Tidy Drawings Of Trees (1993)

    Gibbons, J. (1993-11)

    Report
    The University of Auckland Library

    The tree-drawing problem is to produce a ‘tidy’ mapping of elements of a tree to points in the plane. In this paper, we derive an efficient algorithm for producing tidy drawings of trees. The specification, the starting point for the derivations, consists of a collection of intuitively appealing criteria satisfied by tidy drawings. The derivation shows constructively that these criteria completely determine the drawing. Indeed, the criteria completely determine a simple but inefficient algorithm for drawing a tree, which can be transformed into an efficient algorithm using just standard techniques and a small number of inventive steps. The algorithm consists of an upwards accumulation followed by a downwards accumulation on the tree, and is further evidence of the utility of these two higher-order tree operations.

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  • Using change descriptions to maintain consistency across multiple representations

    Hosking, J.G.; Grundy, J.C. (1995-02)

    Report
    The University of Auckland Library

    We describe a technique for dealing with partial mappings between different representations, both formal and informal, of an evolving software system. This technique uses discrete "change descriptions" to propagate changes between related views. These change descriptions my be used to autiomatically modify affected views, or to annotate the view to indicate manual intervention is required to maintain consistency.

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  • Economic strategy issues for the New Zealand region in the global economy

    Saunders, C.; Dalziel, P.; Kaye Blake, W.

    Report
    Lincoln University

    This report is offered by the AERU at Lincoln University as an issues paper to identify key economic strategy issues for New Zealand, analysed in the context of New Zealand’s position in the global economy. A fundamental ‘New Zealand conundrum’ is that international trends will not allow New Zealand’s economic targets to be met simply by increasing current quantities of primary sector exports and tourism numbers. New Zealand needs to diversify its economy through new knowledge-based enterprises and the use of knowledge intensive services to achieve higher returns for New Zealand traditional export sectors. The report offers this vision for New Zealand’s economic strategy: New Zealand residents through their enterprise and work are all able to enjoy levels of economic well-being that are no lower than enjoyed in other highly developed economies of the world, in the present and in the future. The vision is supported by high level goals under seven headings: • world-class enterprise; • innovation systems; • skills and life-long learning; • public and private investment; • environmental kāwanatanga; • equity and inclusiveness; and • Auckland city. The report argues that economic strategy needs to pay particular attention to the country’s core export sectors on the basis that they are internationally competitive and generate incomes that fuel domestic demand. In order to achieve the above vision, a national economic strategy must guide appropriate investment in physical, financial, human, natural, social and cultural capital that will improve the capability of enterprises to take advantage of New Zealand’s international market opportunities. New Zealand has a high level of physical capital, but low population density means the cost of infrastructure is high and New Zealand does not produce many types of physical capital outside of building and construction. The report recommends policies to address concerns about the way in which public investment is managed at national and regional levels. Examples of this would be reviewing the operation of the Resource Management Act 1991 and creating a robust decision-making process for investments in large-scale infrastructure projects such as water storage. New Zealand’s financial system has been resilient in the current crisis, and the country scores very highly for integrity and low corruption. Nevertheless businesses and observers often identify difficult access to financial capital as a constraint on enterprise expansion. Therefore the report recommends scoping policies for helping small to medium-sized enterprises access working capital such as the United Kingdom Enterprise Finance Guarantee programme. New Zealand has a comprehensive education system, but with a large tail of underachievement and long-standing concerns about weak connections between employers and educators (secondary and tertiary). Appropriately directed investment in human capital can promote inclusiveness of the whole population and address shortages of skills demanded by employers. Life-long learning through adult education is important to encourage participation as skill needs change over time. The report recommends strengthening education directed towards the export-led sectors, including international marketing and other business services. New Zealand has abundant natural resources and a global reputation for clean and green practices, which are attractive to overseas consumers and tourists. The image is under threat in some segments of the market, including for example recent debates about ‘food miles’. The report recommends addressing this by creating a New Zealand eco-label that would tie individual business performance to the overall New Zealand brand that would aim to lead internationally acceptable standards. New Zealand has strong international and domestic networks that aid economic well-being. There is evidence that greater networking of businesses with each other and their communities enhances business development. The report confirms that Māori experience large gaps in basic social security that threatens the sustainability of New Zealand’s economic development. The report supports policies to strengthen international and domestic business networks. It also supports policies to settle historical grievances about Māori property rights and to better position Māori to build and leverage off their collective resources, knowledge, skills and leadership capability. New Zealand has inherited important values from previous generations that are foundational for economic well-being. The fact that English is the country’s dominant language is an international advantage. It has also been stated that New Zealand culture does not acknowledge business success or support community leadership as well as in some countries. The report supports recent proposals that policy should not aim to deny cultural values held by New Zealanders, but to offer strategies for addressing unintended negative consequences for businesses. Because this report is offered as an issues paper, it has necessarily been selective in the issues it has highlighted, but these selections have not been arbitrarily made. Instead, the material presented in this report has drawn on the three authors’ considerable experience in researching strategic economic development issues, summarised in an appendix to this report. That experience led to three major points that frame the report’s contents: 1. A national economic strategy must begin with a credible analysis of the country’s positioning in the global economy. 2. The economy’s capability to respond to international market opportunities is determined by six major types of capital: physical, financial, human, natural, social and cultural. 3. A national economic strategy needs to pay particular attention to the country’s core export sectors on the basis that they are internationally competitive and generate incomes that fuel domestic demand.

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  • Child Poverty Monitor 2015

    Simpson, Jean; Duncanson, Mavis; Oben, Glenda; Wicken, Andrew; Pierson, Melanie (2015-11)

    Report
    University of Otago

    The Child Poverty Monitor and this Technical Report provide data on a set of indicators that assess aspects of child poverty in New Zealand and their implications for child wellbeing. In it are data on income and non-income measures of poverty, including measures that reflect increasing levels of severity. Other data include indicators related to health, living conditions, education, and a selection of economic measures used to assess how well we are doing as a nation that are relevant to the wellbeing of children and their families. The Child Poverty Monitor is a partnership comprising the Office of the Children’s Commissioner, the University of Otago’s New Zealand Child and Youth Epidemiology Service (NZCYES) and the J R McKenzie Trust. The purpose is to compile and share robust information on child poverty measures that are publicly available and easily accessible. Only by having the essential measures on child poverty in New Zealand compiled, published and disseminated annually can we tell how well we are progressing in effectively reducing child poverty in our nation.

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  • Child Poverty Monitor 2014

    Simpson, Jean; Oben, Glenda; Wicken, Andrew; Adams, Judith; Reddington, Anne; Duncanson, Mavis (2014-11)

    Report
    University of Otago

    This Report provides data and technical information on child poverty measures, economic indicators, and child health measures. It builds on the information previously reported in the Children’s Social Health Monitor, thereby providing consistently in these measures. The child poverty measures in this report examine aspects of income poverty, material hardship, and severity and persistence of child poverty. For these measures, we rely heavily on data available in the Ministry of Social Development report Household Incomes in New Zealand: Trends in Indicators of Inequality and Hardship 1982 to 2013. Data are also provided on a few indicators that have economic implications for child poverty: income inequality, unemployment, GDP and reliance on benefits. A new set of measures included in this Technical Report relates to housing. Household crowding and housing costs are highly relevant to child poverty. Data for these indicators have been drawn from the 2001, 2006 and 2013 Censuses and Household Incomes in New Zealand: Trends in Indicators of Inequality and Hardship 1982 to 2013. The health and wellbeing indicators look at hospital admissions and deaths from conditions associated with child poverty, including some infectious and respiratory diseases and injuries; the assault, neglect and maltreatment of children; and infant mortality. For each indicator, there are large disparities for children related to socioeconomic status and ethnicity. Monitoring these health indicators is entirely appropriate, as they are the early signs of the consequences of children living in poverty. Over time, we will look to include additional indicators of child poverty, related to issues such as education, social inclusion, disability and quality of life.

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  • University of Otago Open Access Publishing Survey Results (including Maori ethnicity results)

    White, Richard; Remy, Melanie (2017-05-24)

    Report
    University of Otago

    Abstract: Researchers at the University of Otago are ambivalent about Open Access: in principle they strongly support open access to research literature but their behaviours are driven by the practicalities of cost and publication venue. This document reports the results of a survey carried out in 2015 of University of Otago researchers as to their attitudes towards and behaviours in relation to open access publishing. This version of the report includes a sub-analysis of respondents who selected Maori ethnicity. The original version of the report without this sub-analysis is available via OUR Archive at http://hdl.handle.net/10523/6947 The project page for more information, such as the questions used and the anonymised raw data, is available at https://figshare.com/projects/University_of_Otago_Open_Access_Publishing_Survey_2015-16/17216

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