bluuebunny/crossref_metadata_2025 huggingface dataset:
cis–trans Isomerism among the Octahedral Diaquabis(optically active C-substituted ethylenediamine)nickel(II) Complexes and Their Thermal Reaction Products. An Explanation for a Variety in Colors and Stereochemistry of Lifschitz Complexes
Authors: Ihara Yoshinori , Sakino Tomomi , Ishikawa Mieko , Koyata Takanori
Published: June 2006

The solid-phase thermal reactions of trans-diaquabis(diamine)nickel(II) complexes (trans-[Ni(diamine)2(H2O)2]X2) were investigated by means of TG/DTA and DSC, and high-temperature electronic spectrometry, where the diamine is an optically active diamine such as (1S,2S)-1,2-diphenyl-1,2-ethanediamine or (S)-4-methyl-1,2-pentanediamine, and X is Cl−, Br−, or NO3−. Several complexes were peculiarly transformed into cis-[NiX2(diamine)2] upon thermal deaquation-anation, and then isomerized to trans-[NiX2(diamine)2] upon further heating. The results were in contrast to the reactions of the complexes with the corresponding racemic diamines which underwent a simple deaquation-anation, retaining an original trans configuration. The differences must come from a slight difference in the conformation of diamine ligands between trans-[Ni(R-diamine)(S-diamine)(H2O)2]X2 which is obtained for the rac-diamines and trans-[Ni(R- or S-diamine)2(H2O)2]X2 which is obtained for the optically active diamines.
Development of Chemical Substances Regulating Biofilm Formation
Authors: Yamada Akihiro , Kitamura Hitomi , Yamaguchi Kaori , Fukuzawa Seketsu , Kamijima Chiyuki , Yazawa Kazunaga , Kuramoto Makoto , Wang Gui-Yang-Sheng , Fujitani Yasuyuki , Uemura Daisuke
Published: June 2006

The chemical substances which regulate biofilm formation were examined, and a bioassay system which uses marine bacteria with adhering properties was developed. This bioassay system is suitable for screening crude extracts from marine organisms. Using this system, those substances which regulate biofilm formation were isolated from marine organisms. For example, bis(deacetyl)solenolide D was obtained from the marine sponge Psammaplysilla purpurea. Novel nitroalkanes were also isolated from the Okinawan sponge Callyspongia sp. Ethyl N-(2-phenylethyl)carbamate isolated from the marine bacteria SCRC3P79 (Cytophaga sp.) inhibited biofilm formation. Furthermore, the N,N-dichloro, isocyanide, isothiocyanate, and dithiocarbamate derivatives of 2-(4-nitrophenyl)ethylamine, significantly inhibited the growth of marine attaching bacteria. Interestingly, most of the marine sponges examined contained anti-biofilm compounds, such as benzoic acid, aeroplysinin-I, and bromoageliferin.
A New Convenient Synthesis of 1,2′-Biazulenes by Photolysis of 2-Diazo-1,3-dicyanoazulen-6(2H)-one with Azulene Derivatives
Authors: Lin Shih-Jue , Jiang Shuan-Ya , Huang Tian-Chyuan , Dai Cheng-Shyan , Tsai Pai-Feng , Takeshita Hitoshi , -Lin Yun-Sha , Nozoe (the late) Tetsuo
Published: June 2006

A photolysis of 2-diazo-1,3-dicyanoazulen-6(2H)-one in the presence of azulene derivatives in anhydrous ethyl acetate solution afforded 1,2′-biazulene derivatives, which are otherwise difficult to obtain, in good yields, nearly 90% or more. Accompanying by-products, 1,3-dicyanoazulen-6-ol and 2,5′-biazulene derivatives, were also characterized.
High 1,2-Asymmetric Induction in Radical Reactions: Radical Addition to γ-Hydroxy α,β-Unsaturated Carboxylic Esters and Sulfones
Authors: Ogura Katsuyuki , Kayano Akio , Akazome Motohiro
Published: June 2006

High 1,2-asymmetric induction was realized by the addition of a 1-hydroxy-1-methylethyl radical to conformationally flexible (E)-γ-hydroxy α,β-unsaturated carboxylic esters and sulfones (1 and 2, respectively). Upon the irradiation (> 290 nm) of (E)-1 and benzophenone in 2-propanol, the 1-hydroxy-1-methylethyl radical was generated in situ and added to (E)-1 with high anti-stereoselectivity. The bulkier is the γ-alkyl group of (E)-1, the higher does the selectivity become. Similarly, a radical addition to the acetates of (E)-1 and (E)-2 proceeded stereoselectively in an anti fashion, whereas (Z)-2 exhibited syn-stereoselectivity. The mechanism for these stereoselective radical additions is discussed.
Synthesis and in Vitro Evaluation of 5-closo- and 5-nido-Orthocarboranyluridines as Boron Carriers
Authors: Imamura Ken-ichiro , Yamamoto Yoshinori
Published: June 2006

Sugar-part modified closo-carboranyluridines, 5-(o-carboran-1-yl)-2′,3′-dideoxy-3′-thiauridine 5 and 5-(o-carboran-1-yl)-2′,3′-dideoxy-2′α-phenylthiouridine 6, were synthesized. These newly synthesized closo-carboranyluridines, 5 and 6, and previously synthesized 5-(o-carboran-1-yl)uridine 1 were converted to the corresponding nido-carboranyluridines 18, 19, and 17, respectively. Water-solubility of nido-type 17 was about 100 times higher than that of its closo-counterpart 1. Water-solubilities of sugar modified nido-types 18 and 19 were about 1000 times higher than those of their closo-counterparts 5 and 6 . Cytotoxicities of the nido-types (17 and 19) were about 10 times lower than those of the corresponding closo-counterparts (1 and 6, respectively). Cellular uptake of the nido-types (17 and 19) was in the level similar to that of the closo-counterparts (1 and 6, respectively), although it is often believed that cellular uptake of hydrophilic carboranes (nido-forms) is much lower than that of lipophilic closo-carboranes.
Ruthenium-Catalyzed Addition of Carbon–Hydrogen Bonds in Aromatic Ketones to Olefins. The Effect of Various Substituents at the Aromatic Ring
Authors: Sonoda Motohiro , Kakiuchi Fumitoshi , Chatani Naoto , Murai Shinji
Published: June 2006

To obtain further insight into the new ruthenium-catalyzed reaction of carbon–hydrogen bonds in aromatic ketones with olefins, the effect of various substituents at the aromatic ring is examined. Reaction of o-methylacetophenone with triethoxyvinylsilane (2) in the presence of [Ru(H)2(CO)(PPh3)3] (3)as the catalyst gave the 1 : 1 addition product in quantitative yield. Similarly, the ketone having an o-CF3 group gave the coupling product 9 in 92% yield. However, ortho substituents such as OMe, F, and CN, seem to react with and kill the catalyst so that no efficient reaction was attained. In the cases of the reactions of p-methoxy- and p-fluoroacetophenones with 2, the corresponding 1 : 2 addition products were obtained as the major products. In the cases of m-substituted acetophenones, two different C–H bonds at the ortho positions are available. The C–C bond formation preferentially occurred at the sterically less congested positions. Exceptions are the reactions of m-methoxy- and m-fluoroacetophenones, in which the C–C bond formation took place preferentially at the more congested position. This may be due to the coordination of oxygen or fluorine atom to ruthenium. The factors controlling these selectivities are discussed.
Dried Urushi Lacquer Film Comprizing Several New Types of Inorganic Linkage and Urushiol Matrix
Authors: Shiihara Isao
Published: June 2006

This paper concerns the hardening mechanism of urushi lacquer. The author wished to propose an entirely new mechanism for the room-temperature hardening of urushiol in this natural resin. An investigation of the unit reactions correlated to the mechanism indicated that the catechol moiety of urushiol and metalhydroxides play an important role in hardening.

According to the results, the structure of one component of urushiol as “acetone powder”, obtained from raw urushi sap, was clearly determined. On this basis, it is disclosed that the polymerization of urushiol does not depend on the opening of the sesquiterpene double bond, but is mainly associated with a new type of inorganic ionomer bonding, such as silanolate and carbohydroperoxide–calcium hyroxide, –magnesium hydroxide or –other metal hydroxide combinations’ hydrogen bonding bridges with the urushiol matrix.
Analysis of Microelectrode-Detected ESR (MEDESR) Signals of Nitroxide Radicals in Electrolyte Solutions
Authors: Yokoyama Hidekatsu , Sato Toshiyuki , Ohya-Nishiguchi Hiroaki , Kamada Hitoshi , Kasai Nahoko , Matsue Tomokazu
Published: June 2006

Microelectrode-detected ESR (MEDESR) spectroscopy is a technique that is employed to observe magnetic resonance on the basis of an impedance change of electrodes. The characteristics of MEDESR for nitroxide radicals in electrolyte solutions were analyzed. MEDESR signals were obtained at zero bias-current, suggesting that modulation of the bias-current derived from ESR would not generate MEDESR signals. A good linear relationship between the MEDESR signal intensity and the applied power over a range of up to 150 mW was obtained. The frequency characteristics of the magnetic field modulation indicated that a simple thermal phenomenon would not cause an impedance change in MEDESR. When the radical was distributed on only the electrode surface, no signals were detected. The MEDESR spectra of a nitroxide solution, located outside the electrolytic cell, was detectable. These findings suggest that since MEDESR signals are irrelevant to the radicals in an electrical double layer, they are derived from some changes in the microwaves in the whole resonator. It is speculated, however, that the detecting mechanism of MEDESR is not a simple process of rectifying detection of a microwave change by resonant absorption like in conventional ESR, because the signal intensity of MEDESR is proportional to the irradiation power, and not to the square root as in the conventional ESR.
Biomechanical and Histomorphometric Analyses of Monocortical Screws at Placement and 6 Weeks Postinsertion
Authors: Huja S. S. , Rao J. , Struckhoff J. A. , Beck F. M. , Litsky A. S.
Published: June 2006

Maxillofacial screws are increasingly being used in orthodontics to provide anchorage for tooth movement. The objective of this study was to determine the biomechanical stability as well as the bone tissue response of screws at 6 weeks postinsertion in a canine model. Seven skeletally mature male dogs received 102 screws (2 × 6 mm or 2 × 8 mm) at predetermined sites. Twenty screws became loose or were lost during the 6-week undisturbed healing period. Forty-eight screws were randomized for mechanical testing and 34 for histology. Peak pullout strength was recorded and ∼80-μm sections were examined for histomorphometric parameters. Statistical analyses were conducted by analysis of variance and Tukey-Kramer method. Mean ± SE peak pullout strengths for the various sites ranged from 153.5 ± 37.6 N to 389.3 ± 32.5 N with no significant (P < .05) differences at immediate placement and 6 weeks postinsertion. Bone contact ranged from 79% to 95%. Histomorphometric analyses indicated higher bone formation rate in the mandible than in the maxilla and a gradient of decreasing turnover with increasing distance from the screw interface. These results provide the clinical orthodontist with an estimate of the holding power of these screws and an understanding of early biological healing response associated with self-drilling screws.
Distributed strain measurement for pile foundations
Authors: Klar A. , Bennett P. J. , Soga K. , Mair R. J. , Tester P. , Fernie R. , St John H. D. , Torp-Peterson G.
Published: June 2006

Recent advances in strain measurement using optical fibres provide new opportunities for monitoring the performance of piles. Brillouin optical time-domain reflectometry (BOTDR) is an innovative technique that allows measurement of full strain profiles using standard optical fibres. Distributed optical fibre strain sensors were installed at two sites, and the details of the installation methods are presented. A theoretical analysis that compares pile behaviour evaluated from localised strain measurement at discrete locations and from distributed strain measurements is conducted for the case of a vertically loaded pile in layered soil. Two problems are considered: a load test aiming to establish the load transfer function, and changes in pile–soil interface stress due to nearby tunnelling. Advantages of such a distributed reading for monitoring the performance of pile foundations in layered soils are demonstrated from the results of both cases. Cost analysis results show that the BOTDR measurement is a cost-effective pile monitoring method compared with discrete strain measurement methods such as vibrating-wire strain gauges and fibre Bragg gratings.
Knowledge-based design and construction of driven piles
Authors: Zhang L. M. , Shek L. M. P. , Pang H. W. , Pang C. F.
Published: June 2006

Specified numbers of static load tests (e.g., 1% of working piles) and dynamic tests (e.g., 10% of working piles) are often required in Hong Kong to verify the reliability of driven piles for every single project. In this research, a pile database, the Hong Kong Driven Pile Database, is developed: (a) to systematically compile historic driven pile data, which include pile data, soil investigation data, static load test results, dynamic test results and case pile wave analysis program results; (b) to provide data for reliability evaluation of design methods; (c) to assist in design of future foundation projects based on past experience; and (d) to learn from past failures. The database contains information on 1514 piles, including 308 static load test piles. In this paper, the basic information of the database such as the sources of piling data and the major components of the database is first described. Then the reliability of five termination criteria for piledriving control is evaluated against the pile test information in the database. Subsequently, a performance evaluation of three driving-stress analysis methods is conducted based on information in the database. Finally, to demonstrate possible knowledge-based pile design and construction using the database, a design example is presented illustrating how the database can be used to assist in the early stage of pile design for a future project. The information on hammers, range of final set values and resulting pile performance in case histories of similar projects can be used as a reference for the engineer to expedite design for new projects. The engineer can also learn from the past pile failures contained in the database.
Piled foundations for Eureka Tower, Melbourne, Australia
Authors: Ervin M. C. , Finlayson J. E.
Published: June 2006

The Eureka Tower project in Melbourne is a 92 level (300 m high) residential development. The geology of the site is complex. Bored piled foundations were recommended, requiring socketing into very-high-strength basalt or high-strength siltstone. For the piles proposed to be socketed into the basalt, the successful piling contractor proposed the alternative of continuous flight auger (CFA) piles bearing directly on to the basalt rock. The design bearing stresses for both these CFA piles and the bored piles in siltstone exceeded previously adopted values in Melbourne. Statnamic and dynamic testing was performed on the CFA piles. For the bored piles an extensive investigation programme provided confidence in the socket design, with the assumed conditions verified during construction. This paper was first published in the BGA International Conference on Foundations, University of Dundee, 2003. It has been revised and expanded slightly to cover construction aspects of the project.
On the Importance of Inhibition: Central and Peripheral Manifestations of Nonlinear Inhibitory Processes in Neural Systems
Authors: Thayer Julian F.
Published: June 2006

Inhibitory processes provide for the sculpting of neural action at all levels of the neuraxis. Importantly, it appears that this inhibitory function may be decidedly nonlinear in nature such that a little inhibition goes a long way in guiding the behavior of neural systems. The neural control of the heart is used as a model system to illustrate the nature of this nonlinear inhibitory control. Similar inhibitory processes function in the prefrontal cortex, in the amygdala, and between the prefrontal cortex and the amygdala in the service of organism flexibility, adaptability, and health. It is suggested that a dynamical systems perspective of neural regulation involving nonlinear inhibitory processes may be a useful framework within which to investigate the complex behavior associated with health and disease.
Upper tolerance limit for the largest observation from censored samples
Authors: Takada Yoshikazu
Published: June 2006

This paper deals with obtaining an upper tolerance limit for a largest observation X(n) in an ordered sample of size n from a continuous distribution where the first m observations X(1) < X(2) < … < X(m), l ≤ m < n, have been observed. A criterion of “goodness” of tolerance limit is developed, and a method is given to obtain the best tolerance limit. This method is applied to exponential and Pareto distributions.
Some results on commutation matrices, with statistical applications
Authors: Neudecker H. , Wansbeek Tom
Published: June 2006

The commutation matrix Pmn changes the order of multiplication of a Kronecker matrix product. The vec operator stacks columns of a matrix one under another in a single column. It is possible to express the vec of a Kronecker matrix product in terms of a Kronecker product of vecs of matrices. The commutation matrix plays an important role here. “Super‐vec‐operators” like vec A ⊗ vec A vec (A ⊗ A), and vec{(A ⊗ A)Pnn} are very convenient. Several of their properties are being studied. Both the traditional commutation matrix and vec operator and the newer concepts developed from these are applied to multivariate statistical and related problems.
Estimation of Pr{yp> max(y1, …, yp‐1)}: Predictive approach in exponential case
Authors: Rinco Stefan
Published: June 2006

The structural‐inference approach to predictive distributions is used to derive the estimator ofP= Pr{Yp> max(Y1, …,Yp‐1)} when the independent random variablesY1, …, Ypfollow exponential distributions with unequal location parameters and equal scale parameters. The result is Equation (4.6).
A combinatorial method for products of generalized h‐statistics
Authors: Tracy D. S. , Gupta B. C.
Published: June 2006

The h‐statistic h (Dwyer [1]) is extended to the generalized h‐statistic hP1…Ps such that E(hP1…Ps) with properties similar to polykays. In order to obtain their sampling moments, formulas expressing their products as linear combinations of the same are required. The paper presents a combinatorial method to achieve this. Certain rules are developed and applied to obtain products through weight 5.
An econometric model of the demand for energy in canada part one: The industrial demand for gas
Authors: Khazzoom J. Daniel
Published: June 2006

This is part one of a study of the demand for energy in Canada in the industrial, residential and residential‐commercial markets. The study focuses on the four major sources of energy: gas, oil, coal and electricity. The contents of this paper are as follows:

1. The economic background. The main ideas; a diagrammatic derivation of the free and captive demand; the model.

2. Estimation.The interdependence of demand and price: Natural gas, oil, electricity and coal; the price variables that enter the relationships; data and operational definitions of the variables.

3. Estimation and simulation results for the industrial demand for natural gas. The price‐additive model, the problem of multicollinearity, the alternative.
A note on the expected values of powers of a matrix
Authors: Rahman M. , Ahsanullah M.
Published: June 2006

It is known [Z] that if X is any positive random variable, then E (Xn)>[E (X)]n for any integer n, provided the expectations exist. A matrix generalization of this result for n = ‐1 was given in [1]. We will show that a simple exercise in matrix analysis yields the matrix generalization for any integer n, positive or negative.
Confidence bands from censored samples
Authors: Csőrgő Sándor , Horváth Lajos
Published: June 2006

Several types of asymptotic confidence bands have been proposed in the literature when the data are randomly censored on the right. Introducing new classes of bands, we place the old bands and their relationship to one another within a comprehensive theory of bands. A thorough analysis yields narrower bands and two kinds of modifications which are asymptotically distribution‐ and censor‐free. One of these is useful when the interval on which the bands are constructed is predetermined and the width of the bands is random; the other, when there is a predetermined bound on the width and the interval is random. We illustrate our bands on the Szeged pacemaker data. These methods also provide a general modification of the Kolmogorov band in the uncensored case.
Copules archimédiennes et families de lois bidimensionnelles dont les marges sont données
Authors: Genest Christian , Mackay R. Jock
Published: June 2006

Toute fonction de répartition bidimensionnelle dont les marges sont continues peut être représentée de fçon unique par une copule, c'est‐à‐dire par une fonction de répartition concentrée sur le carré unité et dont les marges sont uniformes. Dans cet article, nous nous intéressons à une classe de copules, dites archimédiennes, qui permet de représenter bon nombre de lois bidimensionnelles connues. Nous donnons des conditions sous lesquelles deux copules de cette classe sont ordonnées stochastiquement et nous examinons les propriétés limites de suites de copules archimédiennes. Nous fournissons également deux nouveaux exemples de families paramétriques de lois bidimensionnelles comprenant comme cas limites les bornes de Frechet et la loi d'indépendance.
Multivariate regression analysis and canonical variates
Authors: Van Der Merwe A. , Zidek J. V.
Published: June 2006

A method called FICYREG of estimating regression coefficients is introduced. This is a generalization to the multivariate regression problem of the James‐Stein estimator. When suitably représentés FICYREG emerges as a rule in which the canonical variates and canonical correlations have an intrinsic role to play. By exploiting these objects FICYREG is able to achieve stability against the influence of the “noise” present in problems where the responses are correlated so that some of the response vector's canonical variates will be essentially independent of all others including the predictors. The least squares (LS) estimator is, by contrast, highly sensitive to this noise. The use of FICYREG is illustrated in terms of an example, and its peformance is compared to the LS estimator when a quadratic loss function is assumed. The cases of both fixed and random predictors are considered. Overall, FICYREG outperforms the LS estimator.
Asymptotic distribution of the latent roots of the noncentral wishart distribution and the power of the likelihood ratio test for nonadditivity
Authors: Carter E. M. , Srivastava M. S.
Published: June 2006

In this paper the asymptotic distribution of the roots of the noncentral Wishart distribution is derived with a remainder term of O(n−2). This distribution is used to derive the asymptotic distribution of the likelihood ratio test for nonadditivity. Some calculated values of the asymptotic power of this test is given. Also, an estimate of σ2 with a bias term of the order O(n−3/2) is given.
Probabilities of moderate deviations under m‐dependence
Authors: Ghosh Malay
Published: June 2006

Consider a stationary sequence {X1, X2,… } of m‐dependent random variables. It is proved that for any constant c > 0, if E|X1|p < ∞ for some p > c2 + 2, then

and

as n → ∞, where μ = E(X1) and

The above results on probabilities of moderate deviations for sample means are then used to obtain similar results for U‐statistics and Von Mises' differentiable statistical functions when the underlying variables form a stationary m‐dependent sequence.
A power study of a rank transform for the two‐way classification model when interaction may be present
Authors: Iman Ronald L.
Published: June 2006

The power of the usual parametric analysis of variance for the two‐way model when interaction may be present is compared with the power of a test based on performing the usual parametric analysis on ranks, i.e., a rank transform is used. While the mathematical theory has not yet been developed for such an approach, this study shows the value of developing the theory for such an approach to the analysis of experimental designs, and indicates that this approach is probably a valid procedure. Simulation results are présentés for three underlying populations: normal, contaminated normal, and exponential. These results show the rank transform approach has a null distribution similar to that of the F‐statistic computed on the raw data in all the cases considered. Though little, if any, loss of power occurs from using the rank transform approach, a significant increase in power is apparent when the underlying population is contaminated normal.
Statistical problems in environmental research
Authors: Ware James H. , Louis Thomas A.
Published: June 2006

Growing concern about the health effects of exposure to pollutants and other chemicals in the environment has stimulated new research to detect and quantify environmental hazards. This research has generated many interesting and challenging methodological problems for statisticians. One type of statistical research develops new methods for the design and analysis of individual studies. Because current research of this type is too diverse to summarize in a single article, we discuss current work in two areas of application: the carcinogen bioassay in small rodents and epidemiologic studies of air pollution. To assess the risk of a potentially harmful agent, one must frequently combine evidence from different and often quite dissimilar studies. Hence, this paper also discusses the central role of data synthesis in risk assessment, reviews some of the relevant statistical literature, and considers the role of statisticians in evaluating and combining evidence from diverse sources.
The interpretation of maximum‐likelihood estimation
Authors: Sprott David A. , Viveros‐Aguilera Román
Published: June 2006

Maximum‐likelihood estimation is interpreted as a procedure for generating approximate pivotal quantities, that is, functions u(X;θ) of the data X and parameter θ that have distributions not involving θ. Further, these pivotals should be efficient in the sense of reproducing approximately the likelihood function of θ based on X, and they should be approximately linear in θ. To this end the effect of replacing θ by a parameter ϕ = ϕ(θ) is examined. The relationship of maximum‐likelihood estimation interpreted in this way to conditional inference is discussed. Examples illustrating this use of maximum‐likelihood estimation on small samples are given.
Recent developments in nonlinear stochastic modelling of social processes
Authors: Bartholomew D. J.
Published: June 2006

After a brief review of social applications of Markov chains, the paper discusses nonlinear (“interactive”) Markov models in discrete and continuous time. The rather subtle relationship between the deterministic and stochastic versions of such models is explored by means of examples. It is shown that the behaviour of nonlinear systems over time periods of practical interest depends critically on the total size as well as on the system parameters. Particular attention is paid to strong and weak forms of quasi‐stationarity exhibited by stochastic systems.
Sampling properties of estimators of the log‐logistic distribution with application to Canadian precipitation data
Authors: Shoukri M. M. , Mian I. U. H. , Tracy D. S.
Published: June 2006

We consider the probability‐weighted moment and the maximum‐likelihood estimators of two parameters in the log‐logistic distribution. Quantile estimators are obtained using both methods. The distributional properties of these estimators are studied in large samples, via asymptotic theory, and in small and moderate samples, via Monte Carlo simulation. The distribution is shown to be appropriate for a wide variety of meteorological data.
Small sample properties of isotonic estimators — bias and mean squared error of linear combinations under normality
Authors: Parsons Van L. , Hoang Thu M.
Published: June 2006

Bias and mean squared error for linear combinations of the isotonic regression estimators are computed. The case of sampling three distinct populations and the case of sampling seven or fewer populations having common mean are studied in detail. Numerical results are given, and comparisons between isotonic and unbiased estimation procedures are made.
A neighbourhood‐based classifier for landsat data
Authors: Owen Art
Published: June 2006

A classifier is developed which uses information from all pixels in a neighbourhood to classify the pixel at the center of the neighbourhood. It is not a smoother in that it tries to recognize boundaries. and it makes explieite use of the relative positions of pixels in the neighbourhood. It is based on a geometric probability model for the distribution of the classes in the plane. The neighbourhood‐based classifier is shown to outperform linear discriminant analysis on some LANDSAT data.
The asymptotic behavior of monotone percentile regression estimates
Authors: Wright F. T.
Published: June 2006

The least‐absolute‐deviation estimate of a monotone regression function on an interval has been studied in the literature. If the observation points become dense in the interval, the almost sure rate of convergence has been shown to be O(n1/4). Applying the techniques used by Brunk (1970, Nonparametric, Techniques in Statistical Inference. Cambridge Univ. Press), the asymptotic distribution of the l1 estimator at a point is obtained. If the underlying regression function has positive slope at the point, the rate of convergence is seen to be O(n1/3). Monotone percentile regression estimates are also considered.
On the power of the t‐test and some rank tests when outliers may be present
Authors: Iman Ronald L. , Conover W. J.
Published: June 2006

The power of some rank tests, used for testing the hypothesis of shift, is found when the underlying distributions contain outliers. The outliers are assumed to occur as the result of mixing two normal distributions with common variance. A small sample case shows how the scores for the rank tests are found and the exact power is computed for each of these rank tests. A Monte Carlo study provides an estimate of the power of the usual two sample t‐test.
On a random series in a hilbert space
Authors: Deo Chandrakant M.
Published: June 2006

Let (Sn) be partial sums of a non‐degenerate sequence of Identically and independently distributed random variables taking values in a separable Hilbert space. Then for 0 ≤ β ≤ 3/2, the series

converges almost nowhere. For β > 3/2 this may not be true.
A consistent system of conditional probabilities which is not compatible with any random field
Authors: Hamilton M. , Anderson W. J.
Published: June 2006

A consistent, Markovian family of conditional densities is constructed which is not compatible with any random field.
An improved ranked set two‐sample mann‐whitney‐wilcoxon test
Authors: Öztürk Ömer , Wolfe Douglas A.
Published: June 2006

The authors present an improved ranked set two‐sample Mann‐Whitney‐Wilcoxon test for a location shift between samples from two distributions F and G. They define a function that measures the amount of information provided by each observation from the two samples, given the actual joint ranking of all the units in a set. This information function is used as a guide for improving the Pitman efficacy of the Mann‐Whitney‐Wilcoxon test. When the underlying distributions are symmetric, observations at their mode(s) must be quantified in order to gain efficiency. Analogous results are provided for asymmetric distributions.
On the stability of maximum‐likelihood estimators of orthogonal parameters
Authors: Cox D. R. , Reid N.
Published: June 2006

If two parameters ψ and λ, are orthogonal, λψ, the maximum‐likelihood estimate of λ for given ψ, varies only slowly with ψ in the neighbourhood of the overall maximum‐likelihood point. The same is true if ψλ is replaced by a nonlinear functionh(ψλ). The detailed form of the variation of ψλ with ψ is studied, and a basis suggested for choosing a particular functionh(ψλ) that shows the dependence in the least informative fashion.
Measures of centrality for multivariate and directional distributions
Authors: Small Christopher G.
Published: June 2006

Measures of centrality that generalize the univariate median are studied and applied to multivariate and directional distributions. A standard example is developed for general multivariate settings, and the uniqueness of the median proved for distributions satisfying certain regularity conditions. In the presence of weaker regularity, this median is shown to be of codimension 2. Conditions are also provided for these measures of centrality to be equivariant under transformations on the sample space. The equivariance of the usual univariate median under monotone transformations is seen as a special case.
Estimators of shift based on statistics of the Kolmogorov‐Smirnov type
Authors: Boulanger Alain
Published: June 2006

This paper is concerned with the estimation of a shift parameter δo, based on some nonnegative functionalHg1of the pair (DδN(x), f̄δN(x)), whereDδN(x) = KN/b {F2,n(x)—F1,m(x + δ)}, +δN(x) = {mF1,m(x + δ) +nF2,n(x)}/N, whereF1,mandF2,nare the empirical distribution functions of two independent random samples (N = m + n), and whereK2N=mn/N.First an estimator δN, is defined as a value of δ minimizing a functionalHof the type ofH1. A second estimator δ1Nis also defined which is a linearized version of the first. Finite and asymptotic properties of these estimators are considered. It is also shown that most well‐known test statistics of the Kolmogorov‐Smirnov type are particular cases of such functionalsH1. The asymptotic distribution and the asymptotic efficiency of some estimators are given.
Uniform asymptotic linearity of a process based on a signed rank statistic
Authors: Boulanger Alain , Eeden Constance Van
Published: June 2006

Consider the process

with, cf. (1.2) on page 265 in B1,

X1, …, XNa sample from a distributionFand, fori= 1, …, N, R, the rank of |X1‐ q1ø| among |X1‐ q1ø|, …, |XN‐ qNø|. It is shown that, under certain regularity conditions onFand on the constantspiand qi, TøN(t) is asymptotically approximately a linear function of ø uniformly intand in ø for |ø| ≤ C. The special case where thepiand theqi, are independent ofiis considered.
On a Berry‐Esséen theorem for a Studentized jackknife L‐estimate
Authors: Cheng Kuang‐Fu
Published: June 2006

Consider a linear function of order statistics (“L‐estimate”) which can be expressed as a statistical function T(Fn) based on the sample cumulative distribution function Fn. Let T*(Fn) be the corresponding jackknifed version of T(Fn), and let V2n be the jackknife estimate of the asymptotic variance of n 1/2T(Fn) or n 1/2T*(Fn). In this paper, we provide a Berry‐Esséen rate of the normal approximation for a Studentized jackknife L‐estimate n1/2[T*(Fn) ‐ T(F)]/Vn, where T(F) is the basic functional associated with the L‐estimate.
Estimation in the presence of incidental parameters
Authors: Mak Tak K.
Published: June 2006

This paper considers the estimation of “structural” parameters when the number of unknown parameters increases with the sample size. Neyman and Scott (1948) had demonstrated that maximum likelihood estimators (MLE) of structural parameters may be inconsistent in this case. Patefield (1977) further observed that the asymptotic covariance matrix of the MLE is not equal to the inverse of the information matrix. In this paper we establish asymptotic properties of estimators (which include in particular the MLE) obtained via the usual likelihood approach when the incidental parameters are first replaced by their estimates (which are allowed to depend on the structural parameters). Conditions for consistency and asymptotic normality together with a proper formula for the asymptotic covariance matrix are given. The results are illustrated and applied to the problem of estimating linear functional relationships, and mild conditions on the incidental parameters for the MLE (or an adjusted MLE) to be consistent and asymptotically normal are obtained. These conditions are weaker than those imposed by previous authors.
The design of experiments for correlated error structures: Layout and robustness
Authors: Herzberg Agnes M.
Published: June 2006

Observations with correlated error structures are sometimes unavoidable. Appropriate designs and analyses are reviewed for such situations. Serious problems can occur if conventional designs and analyses are used when correlated errors and layout are ignored or when the error structure is not known. Robust designs are discussed which guard against these problems.
Bayesian estimation of the difference between two proportions
Authors: Alvo Mayer , Cabilio Paul
Published: June 2006

This paper is concerned with the problem of allocating a fixed number of trials between two independent binomial populations with unknown success probabilities θ1 and θ2, in order to estimate θ1 ‐ θ2 with squared error loss. Introducing independent beta priors on θ1 and θ2, a heuristic allocation procedure is introduced and compared both with the optimal and with the best fixed allocation procedure. Numerical and asymptotic results of these comparisons are given and seem to indicate that there are situations when the best fixed allocation procedure performs almost as well as the optimal procedure.
Enrolment in initial courses in statistics: An exploratory study
Authors: Baggs Ivan
Published: June 2006

In January 1981 a questionnaire was sent to 102 universities and colleges in Canada and the United States seeking information on enrolment in initial courses in statistics. That questionnaire has been analyzed and the results are presented in this paper.
Inférence statistique dans les processus stochastiques: Aperçu historique
Authors: Moore Marc
Published: June 2006

L'étude de I'inférence statistique relative aux processus stochastiques s'est poursuivie suivant deux voies. On a d'une part considéré des problèmes liés à des processus particuliers et, d'autre part, on a aussi considéré l'extension de résultats généraux obtenus pour des variables aléatoires indépendantes. On retrace ici les premières contributions marquantes, on apprécie leur influence, et on donne une idée de l'évolution des activités dans le domaine de l'inférence statistique faite à partir de l'observation d'un processus stochastique.
Bootstrap variance and bias estimation in linear models
Authors: Shao Jun
Published: June 2006

Let θ be a nonlinear function of the regression parameters and θ be its estimator based on the least‐squares method. This paper studies the bootstrap estimators of the variance and bias of θ. The bootstrap estimators are shown to be consistent and asymptotically unbiased under some conditions. Asymptotic orders of the mean squared errors of the bootstrap estimators are also obtained. The bootstrap and the classical linearization method are compared in a simulation study. Discussions about when to use the bootstrap are given.
L1‐Tightness and the law of large numbers in D(IR)
Authors: Daffer Pete , Schiopu‐Kratina Loana
Published: June 2006

This article presents laws of large numbers for random elements of D(IR). The proofs bring forth the similarities between processes restricted to compact sets of D (IR) and processes with increasing trajectories. The results appear to generalize existing results and cover the independent identically distributed case studied by Ranga Rao.
Patterned matrix derivatives
Authors: Tracy D. S. , Jinadasa K. G.
Published: June 2006

A general procedure for obtaining matrix derivatives of functions of nonlinear patterned matrices is proposed. The method is extended to obtain the Jacobians of patterned matrix transformations. Nel (1980) and Wiens (1985) consider the linear patterned cases. The procedure proposed here takes care of these cases as well.
Some robust tests of independence in symmetrical multivariate distributions
Authors: Giri Narayan C.
Published: June 2006

Let X =(x)ij=(111, …, X,)T, i = l, …n, be an n X random matrix having multivariate symmetrical distributions with parameters μ, Σ. The p‐variate normal with mean μ and covariance matrix is a member of this family. Let be the squared multiple correlation coefficient between the first and the succeeding p1 components, and let p2 = + be the squared multiple correlation coefficient between the first and the remaining p1 + p2 =p – 1 components of the p‐variate normal vector. We shall consider here three testing problems for multivariate symmetrical distributions. They are (A) to test p2 =0 against; (B) to test against =0, 0; (C) to test against p2 =0, We have shown here that for problem (A) the uniformly most powerful invariant (UMPI) and locally minimax test for the multivariate normal is UMPI and is locally minimax as p2 0 for multivariate symmetrical distributions. For problem (B) the UMPI and locally minimax test is UMPI and locally minimax as for multivariate symmetrical distributions. For problem (C) the locally best invariant (LBI) and locally minimax test for the multivariate normal is also LBI and is locally minimax as for multivariate symmetrical distributions.
Resolution of Godambe's paradox
Authors: Genest Christian , Schervish Mark J.
Published: June 2006

Two versions of a statistical paradox involving an ancillarity principle have recently been proposed by Godambe (1979, 1982). In this note, we point out that the two versions of his paradox are actually quite different, and we resolve both of them by investigating their relationship to randomization. The first version of Godambe's paradox was criticized earlier by Good (1980), but we believe his argument to be flawed.
The block replacement model with inactivity periods and general cost structure
Authors: Tilquin C. , Cléroux R.
Published: June 2006

There exists a gap between the state of the art in this part of reliability theory devoted to preventive replacement and its applications to real world situations. This dichotomy results in part from the fact that standard models are too simple from the point of view of the cost structure to adequately deal with reality. In considering a general cost structure for the block replacement model with inactivity periods, we hope to contribute to filling this gap.
DT and MDT designs and their applications as breeding experiments
Authors: Aggarwal K.R.
Published: June 2006

The paper contains the analysis and constructions of some useful confounded diallel experiments involving F1's and reciprocal F1's. The incomplete block designs used for this purpose are some four and three class PBIB designs for the s(s‐1) treatments.
On indirect least squares estimation of a simultaneous equation system
Authors: Park Soo‐Bin
Published: June 2006

The indirect least squares (ILS) approach is broadly regarded as a procedure of deriving the structural parameters of a simultaneous equation system indirectly from the estimates of reduced‐form parameters. In this paper it is shown that the ILS approach yields estimators which are identical with the two‐stage least squares estimator, when applied to a single equation, and the three‐stage least squares estimator, when applied to the complete system. Thus a fresh motivation for the ILS method is provided.
Simulation de la fécondité au moyen d'un modèle basé sur la courbe du type I de pearson
Authors: Mitra S. , Romaniuk A.
Published: June 2006

There have been various attempts to use the Pearson type I curve for the purpose of graduating age‐specific fertility rates for human populations. This article attempts to broaden the scope of application of this curve, and discusses three particular areas where such application of this curve would be feasible. These areas are: simulation of age‐specific fertility rates; estimation of certain fertility parameters where statistics are either unreliable or incomplete as is the case in most developing countries; and projections of births. The writers feel that the greatest potential of the Pearsonian type I curve lies in the area of parametric model building for birth projections. One of the important prerequisites for a fruitful application in this area is simplification of procedures and reduction of a number of parameters needed to derive the Pearsonian type I curve. This article presents new methods for deriving this latter curve. The results of the proposed models are tested against data on age‐specific fertility rates for Canada.
A note on estimating the variance of the sample mean in stratified sampling
Authors: Dumouchel W. H. , Rothman E. , Govindarajulu Z.
Published: June 2006

Consider a sample of n observations such that a single observation is randomly drawn from each of n strata, each having mean ui and variance σ2i (i=1,…, n). Two estimators for the variance of the sample mean are proposed and their relative efficiency is examined.
Analyzing point processes subjected to random deletions
Authors: Brillinger David R.
Published: June 2006

Certain nonstationary point process data are viewed as having arisen through time dependent random deletions of a stationary point process. Initially the probability Of deletion is assumed known and estimates of the rate and autointensity function of the inherent stationary process are constructed. Then an estimate of the deletion probability function is developed for the case of the function depending on a finite dimensional parameter. An estimate is provided for the variance of the autointensity estimate.
On a cramér‐von mises type statistic for testing bivariate independence
Authors: Koziol James A. , Nemec Amanda F.
Published: June 2006

A Cramér‐von Mises type statistic for testing bivariate independence, proposed by Hoeffding (1948) and by Blum, Kiefer, and Rosenblatt (1961), is examined in greater detail. The statistic is decomposed into components in the manner of Durbin and Knott (1972), and the components are shown to be related to linear rank statistics. Asymptotic power properties of the Hoeffding statistic and its components in testing for independence with bivariate normal random observations are described; a Monte Carlo study comparing these statistics with other nonparametric statistics for bivariate independence is also reported.
Goodness‐of‐fit tests of hypothesized canonical variables
Authors: Gupta R. D. , Kabe D. G.
Published: June 2006

In the literature goodness‐of‐fit tests for canonical variables are available either in thexspace or in theyspace, see e.g., Bartlett (1951), Kshirsagar (1971, 1972), Radcliffe (1968), and Williams (1952). Here we present goodness‐of‐fit tests for canonical variables in both thexandyspaces. The results appear as extensions of the results of the above authors.
Coupling methods in approximations
Authors: Wang Y. H.
Published: June 2006

Let X and Y be two arbitrary k‐dimensional discrete random vectors, for k ≥ 1. We prove that there exists a coupling method which minimizes P(X ≠ Y). This result is used to find the least upper bound for the metric d(X, Y) = supA|P(X ∈ A) − P(Y ∈ A)| and to derive the inequality d(Σ Xi, Σ Yi) ≤ Σd(Xi, Yi). We thus obtain a unified method to measure the disparity between the distributions of sums of independent random vectors. Several examples are given.
Robustness of theil's mixed regression estimators
Authors: Swamy P.A.V.B. , Mehta J.S.
Published: June 2006

An efficient method for incorporating incomplete prior information in regression analysis was developed by Theil [1963]. In this paper we take up the estimator of coefficients given by this procedure and study its robustness to departures from normality of prior estimators of coefficients. The use of incomplete or biased prior information in regression analysis is also considered and a new estimator for the regression coefficient is suggested.