Research Letters in the Information and Mathematical Sciences

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https://mro.massey.ac.nz/handle/10179/4332

Research Letters welcomes papers from staff and graduate students at Massey University in the areas of: Computer Science, Information Science, Mathematics, Statistics and the Physical and Engineering Sciences. Research letters is a preprint series that accepts articles of completed research work, technical reports, or preliminary results from ongoing research. After editing, articles are published online and can be referenced, or handed out at conferences. Copyright remains with the authors and the articles can be used as preprints to academic journal publications or handed out at conferences. Editors Dr Elena Calude Dr Napoleon Reyes The guidelines for writing a manuscript can be accessed here.

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Now showing 1 - 20 of 130

The disjunctivities of ω-languages
(Massey University, 2000) Yeh, Yow Tzong
An ω-language over a finite alphabet X is a set of infinite sequences of letters of X. Consider congruences IL and Pω, L on X* and a congruence OL on Xω introduced by an ω-language L. IL, Pω, L, and OL are called the infinitary syntactic-congruence, the principal congruence and the ω-syntactic congruence of L, respectively. If IL (Pω, L, OL) is the equality then L is called an I-disjunctive (P-disjunctive, O-disjunctive, respectively) ω- language. Properties concerning such ω-languages are explored and relations between these ω-languages are also studied.
Neural nets - their use and abuse for small data sets
(Massey University, 2000) Meyer, Denny
Neural nets can be used for non-linear classification and regression models. They have a big advantage over conventional statistical tools in that it is not necessary to assume any mathematical form for the functional relationship between the variables. However, they also have a few associated problems chief of which are probably the risk of over-parametrization in the absence of P-values, the lack of appropriate diagnostic tools and the difficulties associated with model interpretation. The first of these problems is particularly important in the case of small data sets. These problems are investigated in the context of real market research data involving non-linear regression and discriminant analysis. In all cases we compare the results of the non-linear neural net models with those of conventional linear statistical methods. Our conclusion is that the theory and software for neural networks has some way to go before the above problems will be solved.
A variation equation for the wave forcing of floating thin plates
(Massey University, 2000) Meylan, Michael H.
A variational equation is derived for a floating thin plate subject to wave forcing. This variational equation is derived from the thin plate equations of motion by including the forcing due to the wave through the integral equation derived using the free surface Green’s function. This equation combines the optimum method forsolving the motion of a thin plate (the variational equation) with the optimum method for solving the wave forcing of a floating body (the Green’s function method). Solutions of the variational equation are presented for some simple thin plate geometries using polynomial basis functions. The variational equation is extended to the case of plates of variable properties and to multiple plates and example solutions are presented.
Decision making in the evaluation, selection and implementation of ERP systems
(Massey University, 2000) Shakir, Maha
The evaluation, selection and implementation (ESI) of ERP systems involve making multiple decisions during the lifecycle of the ERP project. This study tries to map six models of decision-making to the ERP project lifecycle, which is conceptualized using case study data for a health service provider organization in New Zealand. ERP projects are deemed strategic projects for which success or failure has a great impact on the organization. Gaining an understanding of the decision-making process during the life of the project helps in better preparations and planning before and during each phase. Findings suggest that some decision-making models apply to the stages of evaluation, selection and implementation while others are missing. The three models that apply are the administrative, adaptive and political models. This study aids practitioners in better planning and implementation of ERP projects through better understanding the decision-making process. A benefit to academics is in providing new insights for ERP systems implementation, an area where little research is conducted.
Building knowledge-based economies: research projects in knowledge management and knowledge transfer
(Massey University, 2000) Gibson, Virginia R.
Small and medium-sized enterprises (SMEs) are viewed as the growth engines of the new knowledgebased economy. This new economic growth model differs from the old in significant ways, many of which are related to the knowledge base that will be required by the SMEs. Based upon prior research a set of factors important to the success of SMEs in a knowledge-based economy is described. Focusing on those factors related to the knowledge base, the paper concludes with a set of research questions and brief descriptions of three research projects on knowledge management and knowledge transfer.
The Lean Cuisine+ notation revised
(Massey University, 2000) Scogings, Chris
The Lean Cuisine+ notation was developed by Chris Phillips (1995) as an executable semi-formal graphical notation for describing the underlying behaviour of event-based direct manipulation interfaces. Lean Cuisine+ builds on the original Lean Cuisine notation introduced in Apperley & Spence (1989). During the construction of a CASE tool for the notation, as well as further research into the use of the Lean Cuisine+ notation, various changes have been made and the revised notation is presented here. The format and much of the content of this document follows that of Appendix C of Phillips (1993) in order to easily distinguish between the earlier and later versions of the notation.
A renewal cluster model for the inter-arrival times of rainfall events
(Massey University, 2000) Cowpertwait, Paul S.P.
A statistical model, based on a renewal cluster point process, is proposed and used to infer the distributional properties of dry periods in a continuous-time record. The model incorporates a mixed probability distribution in which inter-arrival times are classified into two distinct types, representing cyclonic and anticyclonic weather. This results in rainfall events being clustered in time, and enables objective probabilistic statements to be made about storm properties, e.g. the expected number of events in a storm cluster. The model is fitted to data taken from a gauge near Wellington, New Zealand, by maximising the likelihood function with respect to the parameters. The Akaike Information Criteria is used to select the best fitting distributions from a range of candidates. The log-Normal distribution is found to provide the best fit to the times between successive storm clusters, whilst the Weibull distribution is found to provide the best fit to the times between successive events in the same storm cluster. Harmonic curves are used to provide a parsimonious parameterisation, allowing for the seasonal variation in precipitation. Under the fitted model, the interval series is transformed into a residual series, which is assessed to determine overall goodness-of-fit.
Automatic variance control and variance estimation loops
(Massey University, 2000) Moir, T.J.
A closed loop servo approach is applied to the problem of controlling and estimating variance in nonstationary signals. The new circuit closely resembles but is not the same as, automatic gain control (AGC) which is common in radio and other circuits. The closed loop nature of the solution to this problem makes this approach highly accurate and can be used recursively in real time.
C/C++ implementation of functions of the class LT0
(Massey University, 2000) Calude, Elena; Kay, Peter; Luo, Weiwei
This report describes an on-going implementation, in C/C++, of the functions and schemes of the formal system LT0, presented in the paper Caporaso, Pani and Covino [1]. The final aim is to be able to effectively construct a "small manageable" Exponential Diophantine Equation which represents (in the sense of Chaitin [2]) an algorithmical random binary sequence.
The development of elliptic functions according to Ramanujan and Venkatachaliengar
(Massey University, 2000) Cooper, Shaun
These notes are based on the monograph Development of Elliptic Functions according to Ramanujan by K. Venkatachaliengar [2]. The goal of the notes is to show how some of the main properties of Jacobian and Weierstrass elliptic functions can be developed in an elementary way from the 1Ã1 function. All of the ideas presented in these notes can be found in Venkatachaliengar's book. The only thing I have done is to rearrange the order in which the material is presented. I am entirely responsible for any errors in these notes, and would be very grateful to be informed about them, whether they be large or small.
Building an inexpensive parallel computer
(Massey University, 2000) Grosz, Lutz; Barczak, Andre
A survey of generalized inverses and their use in stochastic modelling
(Massey University, 2000) Hunter, Jeffrey J.
In many stochastic models, in particular Markov chains in discrete or continuous time and Markov renewal processes, a Markov chain is present either directly or indirectly through some form of embedding. The analysis of many problems of interest associated with these models, eg. stationary distributions, moments of first passage time distributions and moments of occupation time random variables, often concerns the solution of a system of linear equations involving I – P, where P is the transition matrix of a finite, irreducible, discrete time Markov chain. Generalized inverses play an important role in the solution of such singular sets of equations. In this paper we survey the application of generalized inverses to the aforementioned problems. The presentation will include results concerning the analysis of perturbed systems and the characterization of types of generalized inverses associated with Markovian kernels.
Critical success factors for developing an e-business strategy
(Massey University, 2000) Viehland, Dennis W.
e-Business is the new, leading edge of electronic commerce. Organizations are using e-business applications such as enterprise resource planning, customer relationship management and e-procurement to transform traditional businesses into e-businesses. As organizations pursue an e-business strategy what are the five or six most important factors to consider? What are the opportunities? What are the threats? Answering these questions is the primary purpose of this paper. First, e-business is defined and placed in an historical context with its evolution through the electronic commerce concept. Then six critical success factors for developing e-business strategy are discussed and mini-case studies are used to illustrate their application in real businesses.
Intracellular calcium oscillations
(Massey University, 2000) Coxhead, Peter D.
Oscillations and traveling waves of calcium: a simplified model
(Massey University, 2000) Singer, Benjamin
We construct a heuristic model of calcium oscillations in pancreatic acinar cells. The model is based on the two-state model of Sneyd et al. (Sneyd, J., A. LeBeau and D. Yule, 2000, Traveling waves of calcium in pancreatic acinar cells: model construction and bifurcation analysis, Physica D, in press) and is similar in spirit to the FitzHugh reduction of the Hodgkin-Huxley equations. The simpli¯ed model successfully reproduces the oscillatory behavior and wave behaviour of the more complex model. In particular, the simpli¯ed model provides an example of a simple, physiologically relevant model that has a T-point and an associated spiral branch of homoclinic orbits.
Discrete-time variance tracking with application to speech processing
(Massey University, 2001) Moir, T.J.
Two new discrete-time algorithms are presented for tracking variance and reciprocal variance. The closed loop nature of the solutions to these problems makes this approach highly accurate and can be used recursively in real time. Since the Least-Mean Squares (LMS) method of parameter estimation requires an estimate of variance to compute the step size, this technique is well suited to applications such as speech processing and adaptive filtering.
An ES process framework for understanding the strategic decision making process of ES implementations
(Massey University, 2001) Shakir, Maha
Enterprise systems (ES) implementations are regarded costly, time and resource consuming and have a great impact on the organization in terms of the risks they involve and the opportunities they provide. The steering committee (SC) represents the group of individuals who is responsible for making strategic decisions throughout the ES implementation lifecycle. It is evident from recent studies that there is a relationship between the decision making process and ES implementation success. One of the key elements that contribute to the success of ES implementations is a quick decision making process (Brown and Vessey, 1999; Gupta, 2000; Parr, et al., 1999). This study addresses the strategic decision-making process by SC through its focus on four research questions (1) How can the strategic decision-making process in the implementation of ES be better understood, during each phase of the ES implementation lifecycle? (2) What is the process by which the SC makes strategic decisions? (3) How are fast decisions made? and (4) How does decision speed link to the success of ES implementation? Process models of ES implementation will provide a framework to investigate the strategic decision making process during each phases of the ES implementation lifecycle. Patterns in the decision making process will be explored using strategic choice models. This study develops a research model that focuses on the decision making process by steering committee to explore research questions. It concludes with identifying contributions to both IS research and business practitioners.
Issues in data collection: missing data and the 2001 New Zealand census
(Massey University, 2001) Scheffer, Judi
Missing data plagues all surveys, and to a degree the New Zealand Census suffers from the same malaise. While it is not a high level of missingness, it is present. If not correctly dealt with; just deleting cases with missing data will lead to biased conclusions, particularly if the missingness mechanism is NMAR. Some missing data may be inevitable; sometimes a respondent may be incapable of answering a question. This is usually MAR. If however the respondent refuses to answer a question because of say having a high income, then the results of the income question will be biased. Over time there have been a growing number of people employing avoidance tactics so as not to be classified as a refusal, but to make enumeration just too difficult. Anecdotal evidence among enumerators shows that this accounts for about 5% of respondents.
Algebraic conversions
(Massey University, 2001) Mills, Bruce
An examination of the pure algebraic properties of computational type conversion leads to a new generalizations of the concept of a homomorphism for which the term conversion seems appropriate. While an homomorphism is a mapping that respects the value of all terms, a conversion is a mapping that respects the value of all sufficiently small terms. Such a mapping has practical value, as well as theoretical interest that stems from conversions forming a category. This paper gives a precise definition of the concept and demonstrates an application to formal computer science based on work completed by the author in his PhD thesis.
E-commerce technology adoption framework by New Zealand small to medium size enterprises
(Massey University, 2001) Rashid, M.A.
This paper attempts to highlight a framework for the adoption of electronic commerce (EC) technologies in New Zealand with specific interest in the small to medium-size enterprise (SME) sector of the economy. The main thrust of the research was to develop the framework for EC adoption by the New Zealand SMEs and hence study the accelerators and impediments to the adoption and diffusion of EC technologies. The paper shows how IS/IT adoption and diffusion theories and practicalities can be explored for developing the proposed EC adoption framework. It is argued that results from research case studies based on the framework are able to identify the factors influencing and leading to the adoption of e-commerce technologies by the New Zealand SMEs.

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