302 results for Working or discussion paper, 1990

  • Informal introduction to Starlog

    Cleary, John G. (1993-10)

    Working or discussion paper
    University of Waikato

    This report provides an informal and gentle introduction to the logic programming language Starlog and is intended to eventually form the first chapter of a book on Starlog. Like Prolog (a widely known and common logic programming language), Starlog programs consist of sets of Horn clauses. Starlog differs from Prolog in the way it is executed and in the use of logical time to order execution. The style of programming that results tends to be different from Prolog and similar to programs for relational databases.

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  • Proving the existence of solutions in logical arithmetic

    Cleary, John G. (1993-10)

    Working or discussion paper
    University of Waikato

    Logical arithmetic is a logically correct technique for real arithmetic in Prolog which uses constraints over interval representations for its implementation. Four problems with the technique are considered: answers are conditional and uninformative; iterative computations may lead to unboundedly large constraint networks; it is difficult and ineffective to deal with negation; and computing extrema is often not effective. A solution to these problems is proposed in the form of "existential intervals" which record the existence of a solution to a set of constraints within an interval. It is shown how to operate on existential intervals and how they solve the four problems.

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  • The design of an optimistic AND-parallel Prolog

    Cleary, John G.; Olthof, Ian (1993-10)

    Working or discussion paper
    University of Waikato

    A distributed AND-parallel Prolog implementation is described. The system can correctly handle all pure Prolog programs. In particular, it deals with the problem of distributed backtracking. Conflicts in variable bindings are resolved by assigning a time value to every unification. Bindings with smaller time values are given precedence over those with larger time values. The algorithm is based on the optimistic Time Warp system, with Prolog-specific optimizations. The optimizations include two new unification algorithms that permit unification and backtracking in any order. The result is a system which can fully exploit the parallelism available in both dependent and independent AND-parallelism.

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  • Parallel programming with PICSIL1

    Pearson, Murray W.; Melchert, Matthew (1993-10)

    Working or discussion paper
    University of Waikato

    This paper describes the background and development of PICSIL1 a visual language for specifying parallel algorithms using structured decomposition. PICSIL1 draws upon graphical and textual specification techniques; the first for high level structure of an algorithm, the second for more detailed functional specifications. The graphical specification techniques used in PICSIL1 are based on Data Flow Diagrams (DFDs) and are well suited to the assembly and interconnection of abstract modules. Minor modifications to DFDs have however had to be made to make them suitable for describing parallel algorithms. These include the ability to dynamically replicate sections of a diagram and change the structure of parts of a diagram dependent on data being processed. Work is proceeding on the development of an editor to allow the direct capture and editing of PICSIL1 descriptions. In the near future development of compiler and visual debugging tools are planned.

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  • Discrete Fourier Transforms of Fractional Processes August

    Phillips, Peter (1999)

    Working or discussion paper
    The University of Auckland Library

    Discrete Fourier transforms (dft's) of fractional processes are studied and a exact representation of the dft is given in terms of the component data. The new representation gives the frequency domain form of the model for a fractional process, and is particularly useful in analyzing the asymptotic behavior of the dft and periodogram in the nonstationary case when the memory parameter d > 1/2. Various asymptotic approximations are suggested. It is shown that smoothed periodogram spectral estimates remain consistent for frequencies away from the origin in the nonstationary case provided the memory parameter d < 1. When d = 1, the spectral estimates are inconsistent and converge weakly to random variates. Applications of the theory to log periodogram regression and local Whittle estimation of the memory parameter are discussed and some modified versions of these procedures are suggested.

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  • Industry Premium: What we Know and What The New Zealand Data Say

    Bandyopadhyay, Debasis (1999)

    Working or discussion paper
    The University of Auckland Library

    This paper critically reviews conventional explanations of why the individual income reflects an industry premium. It presents four facts about industry premiums in New Zealand to highlight the limitation of those explanations. In particular, it suggests that competitive theories that refer to unobservable characteristics or compensating wage differentials are too broad and non-competitive theories that rely on the efficiency wage hypothesis are too narrow to successfully explain what the New Zealand data reveal. Employees receive industry premium, but so do the self-employed, and do so more than the employees if uneducated; but the premium difference falls as the education level rises.

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  • Public Disclosure of Patent Applications, R&D, and Welfare

    Aoki, Reiko; Spiegel, Yossi (1998)

    Working or discussion paper
    The University of Auckland Library

    In Europe and in Japan, patent applications are publicly disclosed after 18 month from the filing date regardless of whether a patent has been or will be registered. In the U.S. in contrast, patent applications are publicly disclosed only when a patent is granted. In this paper we examine the consequences of this difference for (i) firm's R&D and patenting behavior, (ii) consumers' surplus and social welfare, and (iii) the incentives of firms to innovate, in a setting where patent protection is imperfect in the sense that patent applications may be rejected and patents are not always upheld in court. The main conclusions are that public disclosure leads to fewer patent applications and fewer innovations, but for a given number of innovations, it raises the probability that new technologies will reach the product market and thereby enhances consumers' surplus and possibly total welfare as well .

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  • Distribution of Human Capital and Economic Growth

    Bandyopadhyay, Debasis (1997)

    Working or discussion paper
    The University of Auckland Library

    This paper provides an empirically tractable model of economic growth where the distribution of human capital is central to understanding the key issues. Long run growth is possible only if the distribution of human capital belongs to a known class such that investment in education, the model's engine of growth, exceeds inter-generational depreciation of human capital. The model contributes to understanding of the puzzle of growth disparities among countries by exhibiting multiple steady states under alternative paradigms of growth. It provides a purely neoclassical model to explain why a lower income inequality may correspond to a higher rate of growth.

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  • A LAD Regression Under Non-Standard Conditions

    Rogers, Alan (1997)

    Working or discussion paper
    The University of Auckland Library

    Most work on the asymptotic properties of least absolute deviations (LAD) estimators makes use of the assumption that the common distribution of the disturbances has a density which is finite and positive at zero. We consider the implications of weakening this assumption in a regression setting. We see that the results obtained are similar in flavor to those obtained in a least squares context when the disturbance variance is allowed to be infinite: both the shape of the limiting distribution and the rate of convergence to it is affected in reasonably simple and intuitive ways. As well as conventional regression models we outline results for some simple autoregressive models which may have a unit root and/or infinite error variance.

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  • A Cooperative Game Approach to Patent Litigation, Settlement, and Allocation of Legal Costs

    Aoki, Reiko; Hu, Jin (1999)

    Working or discussion paper
    The University of Auckland Library

    We analyze litigation and settlement behavior in case of patent infringement using the Nash Bargaining Game framework. We show that litigation can be the Pareto efficient outcome. We also show that when there is settlement, the transfer payment from the defendant to the plaintiff is increasing in its own legal cost and decreasing in that of the plaintiff, reflecting the bargaining power on both sides. We also compare the American and English rules of cost allocation when legal costs are endogenously determined.

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  • Empirical Characteristic Function in Time Series Estimation

    Knight, John; Yu, Jun (1999)

    Working or discussion paper
    The University of Auckland Library

    Since the empirical characteristic function is the Fourier transformation of the emipirical distribution function, it retains all the information in the sample but can overcome difficulties arising from the likelihood. This paper discusses an estimation method using the empirical characteristic function for stationary processes. Under some regularity conditions, the resulting estimators are shown to be consistent and asymptotically normal. The method is applied to estimate Gaussion ARMA models. The optimal weight functions and estimating equations are given for in detail. Monte Carlo evidence shows that thc empirical characteristic function method can work as well as the exact maximum likelihood method and outperforms the conditional maximum likelihood method.

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  • Do Topics Diffuse from Core to Periphery Journals?

    Bandyopadhyay, Debasis; Yu, Jun (1999)

    Working or discussion paper
    The University of Auckland Library

    We examine the interests among competing topics of macroeconomics by tracing publication frequencies of these topics as recorded in the EconLit database over the period from 1969 through 1996. We find some evidence in the data that the interests on a topic in the core journals relative to the periphery journals decreases as the topic gets old. We, however, find that an increasing interest on a topic in the periphery journals Granger causes an increase in interest on the same topic in the core journals but not vice versa. The evidence, therefore, suggests that the topics do not gradually diffuse from the core journals to the periphery journals. Nevertheless, we find that one could economize their literature search by focusing on that smaller set of core journals.

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  • The Impact of Recent Welfare Reforms on Labour Supply Behaviour In New Zealand

    Maloney, Tim (1998)

    Working or discussion paper
    The University of Auckland Library

    New Zealand recently initiated sweeping reforms to its social welfare programmes by cutting benefits and tightening eligibility criteria. One of the objectives of these reforms was to provide incentives for people to enter or re-enter the labour force. Econometric analysis is used in this paper to isolate the actual effects of these benefit reforms on labour supply. Previous research in many counties has often failed to accurately measure the extent of these work disincentives, or to observe variation in these programmes that would allow this empirical analysis to take place. The structure of these benefit programmes in New Zealand, and the nature of these reforms offers a unique opportunity to identify these behavioural responses. Quarterly random samples of individuals between 1985 and 1995 are used to isolate the effects of these reforms, while controlling for a wide variety of other influences. This study finds compelling evidence that these benefit reforms resulted in a substantial increase in aggregate labour supply in this country.

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  • Ideology, Asymmetric Information, and Campaign Contributions to Politicians

    Boyce, John (1998)

    Working or discussion paper
    The University of Auckland Library

    This paper considers a model of interest group competition to influence policy outcomes when politicians and some interest groups hold private information about the polic y preferences (ideology) of politicians. Politicians cannot credibly reveal their ideology to others because all politician types prefer more campaign contributions to fewer. However, informed interest groups do convey some information about politician_s type by their contributions. If an uninformed group is a friend (it prefers moving the given policy in the same direction as the informed group), the informed group will truthfully reveal whether or not the politician is receptive to contributions. However, if the uninformed group is an enemy (it prefers a policy movement in the opposite direction), with the same signal the informed group only partially reveals whether the politician is receptive to contributions from its enemies. Empirical evidence is presented that supports the hypothesis that political action committee contributions are informative as well as persuasive.

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  • What Do Uncertainty-Averse Decision-Makers Believe? A Note

    Ryan, Matthew (1999)

    Working or discussion paper
    The University of Auckland Library

    The aim of this note is to plug an important gap in our understanding of the epistemic foundations of uncertainty-averse behavior. For Choquet expected utility maximizers (Schmeidler (1989)), the beliefs which motivate uncertainty-averse choice are frequently identified using Dow and Werlang's (1994) notion of support for convex capacities. Building on the work of Morris (1997), we present a new, preference-based belief operator which is is shown to characterize such epistemic inferences. This makes their behavioral foundations transparent, and enables readier comparison with alternative epistemic models for such behavior.

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  • Patent Licensing with Spillovers

    Aoki, Reiko; Tauman, Yair (1998)

    Working or discussion paper
    The University of Auckland Library

    The purpose of this paper is to study the effect of spillover on extent of licensing when cost reducing innovation is introduced and licensed to a number of oligopolistic firms. We characterize the equilibrium number of licenses that are sold through an auction. An increase in the number of licenses has two effects. First, it increases the competition between the licensees. Second, due to spillover, the non-licensees become more efficient contributing to even more competition. We find that despite these effects, a patentee of a significant innovation will sell more licenses when there is spillover than without spillover thereby inducing even more competition. In this case, consumer surplus will be greater with spillover. However, if the innovation is less significant, then the patentee will sell less licenses with spillover thereby restrict competition. In this case the market price will be higher and the consumer surplus will be smaller.

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  • Does Enviromental Regulation Stimulate Innovative Responses? Evidence from U.S. Manufacturing

    Ratnayake, Ravi (1999)

    Working or discussion paper
    The University of Auckland Library

    A wide spread concern can be witnessed among businessmen, policy makers and academics about the role of environmental regulations on innovative responses. In this study, we examine whether these regulations enhance or hinder R&D expenditure using the data for eight major U.S industries for the period 1982 to 1992. We find no strong evidence to support the view that environmental regulations proxied by abatements costs have any significant impact on the pollution abatement technology.

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  • Health Insurance in the Presence of Physician Price Discrimination

    Vaithianathan, Rhema (1998)

    Working or discussion paper
    The University of Auckland Library

    We model equilibrium in the health insurance market, when a monopolistic physician price discriminates on the basis of coinsurance rates. The physician extracts surplus created in the insurance market, leading to some consumers remaining uninsured. This 'hold-up' problem is solved if the physician and insurer integrate or enter a price agreement prior to writing the insurance contract. Both approaches improve insurer and physician profitability, and restore complete insurance market coverage. This paper therefore explains both partial insurance market coverage and the emergence of various contractual and ownership arrangements in the health insurance industry.

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  • A Test Statistic and Its Application in Modelling Daily Stock Returns

    Shao, Qi-Man; Yu, Hao; Yu, Jun (1999)

    Working or discussion paper
    The University of Auckland Library

    In this paper we propose a test statistic to discriminate bctween models with finite variance and models with infinite variance. The test statistic is the ratio of the sample standard deviation and the sample interquartile range. Both asymptotic and finite sample propert,ies of the test statistic are discussed. We show that the test is consistent against infinite-variance distributiorls and has small size distortions. The statistic is applied to compare the competing models for S&P 500 index returns. Our test can not reject most distributions with finite variance for both a pre-crash sample and a post-crash sample, and hence supports the literature. However, for a sample including crash days, our test suggests that the finite-variance distributions must be rejected. The finding is different from what have been discovered in the recent literature.

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  • New Unit Root Asymptotics in the Presence of Deterministic Trends

    Phillips, Peter (1998)

    Working or discussion paper
    The University of Auckland Library

    Recent work by the author (1998) has shown that stochastic trends can be validly represented in empirical regressions in terms of deterministic functions of time. These representations offer an alternative mechanism for modelling stochastic trends. It is shown here that the alternate representations affect the asymptotics of all commonly used unit root tests in the presence of trends. In particular, the critical values of unit root tests diverge when the number of deterministic regressors K -+ rn as the sample size n + w. In such circumstances, use of conventional critical values based on fixed K will lead to rejection of the null of a unit root in favour of trend stationarity with probability one when the null is true. The results can be interpreted as saying that serious attempts to model trends by deterministic functions will always be successful and that these functions can validly represent stochastically trending data even when lagged variables are present in the regressor set, thereby undermining conventional unit root tests.

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