bluuebunny/crossref_metadata_2025_split huggingface dataset:
The use of analysis of variance procedures in biological studies
Authors: Williams Byron K. 
Published: June 2007

AbstractThe analysis of variance (ANOVA) is widely used in biological studies, yet there remains considerable confusion among researchers about the interpretation of hypotheses being tested. Ambiguities arise when statistical designs are unbalanced, and in particular when not all combinations of design factors are represented in the data. This paper clarifies the relationship among hypothesis testing, statistical modelling and computing procedures in ANOVA for unbalanced data. A simple two‐factor fixed effects design is used to illustrate three common parametrizations for ANOVA models, and some associations among these parametrizations are developed. Biologically meaningful hypotheses for main effects and interactions are given in terms of each parametrization, and procedures for testing the hypotheses are described. The standard statistical computing procedures in ANOVA are given along with their corresponding hypotheses. Throughout the development unbalanced designs are assumed and attention is given to problems that arise with missing cells.
An alternative description of the stochastic process generating security returns
Authors: Espahbodi Hassanali , Espahbodi Pouran , Tehranian Hassan 
Published: June 2007

AbstractThis research questions the appropriateness of the market model in describing the stochastic process generating security returns. A new descriptive model which considers the adaptive behaviour of economic agents and their partial adjustment to new information is proposed. Empirical results indicate that the proposed model is superior to the conventional market model in describing the returns generating process. These findings raise questions about previous studies concerning the information content of specific events or concerning the market efficiency.
Effect of superficial velocity on pressure fluctuations in a gas–solid fluidized bed: A stochastic analysis
Authors: Neogi D. , Fan L. T. , Yutani N. , Nassar R. , Walawender W. P. 
Published: June 2007

AbstractThe characteristics of a gas–solid fluidized bed are influenced by complicated and stochastic phenomena, e.g. jetting and the bubbling of the fluidizing medium and the motion of the fluidized particles. In this study pressure fluctuations due to the bubble movement were measured by means of a pressure probe over a range of time. The resultant time series have been analysed by determining their autocorrelation function and power spectrum with emphasis on the examination of the effect of the superficial velocity of the fluidizing gas. A stochastic model of bubble motion in a fluidized bed has been developed. This model visualizes the bubble motion in a fluidized bed to consist of the random movement, generating irregular signals, and the linear movement, generating wave‐like signals. A theoretical autocorrelation function and a power spectral density function have been derived based on the model.
Presentation of problem: Performance of jitter in discriminating between normal and dysphonic speakers
Authors: Schoentgen Jean 
Published: June 2007

AbstractThe data we deal with are acoustic feature values computed from speech signals produced by normal control speakers and speakers suffering from a laryngeal pathology. The problem is (i) to compare the discriminatory performance of a given acoustic feature with other features of the same family; (ii) to compare the performance of corresponding features in studies carried out on corpora which were not identical and which did not contain the same number of speakers; (iii) to express quantitatively the share of laryngeal pathologies which could be detected reliably by acoustic means alone. We propose to accomplish tasks (i) to (iii) by separating pooled control and risk groups on the basis of the acoustic feature values alone and by evaluating the quality of approximation of the original groups so realized. In order to evaluate this quality we compute a merit factor satisfying the following properties: (1) to be independent of the number of speakers contained in the pooled control and risk groups; (2) to increase and decrease linearly with the detection and false alarm rates, respectively; (3) to take on values between 0 (no discrimination at all) and 1 (perfect discrimination). We also address the question of the confidence one may have in the merit factor values so achieved, i.e. we describe a method of computing the probability that a merit factor value might have been realized by chance alone.
Clusterwise aggregation of relations
Authors: Gaul Wolfgang , Schader Martin 
Published: June 2007

AbstractIn this paper we handle the general problem of finding q(> 1) central relations on a set of objects which best fit the information contained in a finite number of given relations on that set. The proposed CAR (clusterwise aggregation of relations) algorithm allows one to consider the well‐known situation of determining a single central relation as a special case (q = 1) and takes into account the fact that the representation of appropriately selected subsets of relations by different central relations can provide additional insights into whether different clusters or segments of relations exist in the given set of relations. Two examples demonstrate the usefulness of the suggested approach.
Prognostic of glial tumours
Authors: Commenges D. , Dartigues J. F. , Rossi Carla 
Published: June 2007

AbstractWe deal with the problem of finding a suitable model to predict survival of patients suffering from glial tumours as a function of several covariates.Estimation is based upon a retrospective study on 192 patients. Data were collected in the Hospital of Bordeaux and are analysed by Commenges and Dartigues1using a Cox model.In the present paper we use dynamic Bayesian models which allow effects of the covariates to change with time through a stochastic structure.The survival function at one year is also calculated as a function of the covariates with the highest prognostic values and two factors (linear combinations of the covariates) are identified which synthesize information related to the general state of the patient (age, first symptom, etc.) and the characteristics of the tumour (diameter, localization, etc.), respectively. Survival at one year is then calculated as function of the two factors. Results are reported in tabular and graphic forms.
Statistical methods in multi‐speaker automatic speech recognition
Authors: Boyer A. , Di Martino J. , Divoux P. , Haton J. P. , Mari J. F. , Smaili K. 
Published: June 2007

AbstractAutomatic speech recognition and understanding (ASR) plays an important role in the framework of man‐machine communication. Substantial industrial developments are at present in progress in this area. However, after 40 years or so of efforts several fundamental questions remain open. This paper is concerned with a comparative study of four different methods for multi‐speaker word recognition: (i) clustering of acoustic templates, (ii) comparison with a finite state automaton, (iii) dynamic programming and vector quantization, (iv) stochastic Markov sources. In order to make things comparable, the four methods were tested with the same material made up of the ten digits (0 to 9) pronounced four times by 60 different speakers (30 males and 30 females). We will distinguish in our experiments between multi‐speaker systems (capable of recognizing words pronounced by speakers that have been used during the training phase of the system) and speaker‐independent systems (capable of recognizing words pronounced by speakers totally unknown to the system). Half of the corpus (15 male and 15 female) were used for training, and the remaining part for test.
Model of traffic flow and blocking probability analysis of an m‐asymmetrical two stage incomplete link system
Authors: Tralhǎo Lino M. , Craveirinha José F. , Clímaco Joáo N. 
Published: June 2007

AbstractIn the first part of this study we present and review a simplified model for the traffic flow between the switches of a modular switching system. In the second part, an approximated model for calculating the blocking probability on a system with this type of architecture is presented and then generalized to a structure here defined as an m‐asymmetrical incomplete link system. The model is based on the probabilistic hypothesis of Jacobaeus and leads to a system of formulae which may be calculated using a computing language allowing for recursive subprograms.
Factors affecting the demand for softwood lumber in the united states
Authors: Uri Noel D. , Boyd Roy 
Published: June 2007

AbstractThis study sets out to examine whether the demand for softwood lumber in the United States is responsive to various market factors including the price of softwood lumber, the price of other building materials, and the level of economic activity (e.g. housing starts). Concern in the analysis is focused on overcoming some of the methodological shortcomings found in previous studies of this issue. The results are conclusive. The quantity of softwood lumber demanded does respond to the various economic factors considered. Moreover, when the structural stability of the estimated relationships is investigated, the results suggest that the demand for softwood lumber regionally in the United States has remained unaltered over the sample period (1950–1985).
A strategic r&d planning model with an application to an energy research organization
Authors: Chao Hung‐Po , Peck Stephen C. , Steve Wan Y. 
Published: June 2007

AbstractThis paper describes a two‐stage strategic planning model for determining the optimal R&D portfolio in the presence of both exploratory and developmental research projects. An example is illustrated in the context of energy research. Research portfolios are analysed using a Bayesian approach in which probability assessments are updated as new information generated by exploratory research becomes available. Useful insights are obtained through sensitivity analysis. It is found that exploratory research tends to exhibit a lumpy characteristic.
Some open problems in the design and use of modern production systems
Authors: Harhalakis G. , Proth J. M. 
Published: June 2007

AbstractDuring the past two decades, manufacturing systems have moved towards automation, integration and modularity. These trends will certainly continue in the future due to the constraints of the market and to evolution of resources and worker requirements. As a consequence, the design and use of manufacturing systems are increasingly expensive. Numerous methods and tools have been developed to face up to this situation, but some complementary aids could be provided for designers and manufacturing engineers. The goal of this paper is to present important open problems whose solutions could certainly significantly improve the design and use of modern production systems.
Stochastic signal analysis: Numerical representation and applications to system theory
Authors: Valderrama Mariano J. 
Published: June 2007

AbstractAlternative procedures for representing a stochastic signal as a denumerable series with uncorrelated terms are developed. The study includes considerations about parametric rescaling and its repercussions on the orthogonal expansion, as well as numerical techniques for approaching such an expansion. In addition, applications to the Gaussian characterization of stochastic signals, filtering and stochastic modelling are treated.
Improving two theorems of bose on difference families
Authors: Buratti Marco 
Published: June 2007

AbstractIn [2] R. C. Bose gives a sufficient condition for the existence of a (q, 5, 1) difference family in (GF(q), +)—where q ≡ 1 mod 20 is a prime power — with the property that every base block is a coset of the 5th roots of unity. Similarly he gives a sufficient condition for the existence of a (q, 4, 1) difference family in (GF(q, +)—where q ≡ 1 mod 12 is a prime power — with the property that every base block is the union of a coset of the 3rd roots of unity with zero. In this article we replace the mentioned sufficient conditions with necessary and sufficient ones. As a consequence, we obtain new infinite classes of simple difference families and hence new Steiner 2‐designs with block sizes 4 and 5. In particular, we get a (p4α, 5, 1)‐DF for any odd prime p ≡ 2, 3 (mod 5), and a (p2α, 4, 1)‐DF for any odd prime p ≡ 2 (mod 3). © 1995 John Wiley & Sons, Inc.
A generalization of the ray‐chaudhuri‐wilson theorem
Authors: Snevily Hunter S. 
Published: June 2007

AbstractLet K = {k1,…,kr} and L = {l1,…,ls} be two sets of non‐negative integers and assume ki > lj for every i,j. Let F be an L‐intersecting family of subsets of a set of n elements. Assume the size of every set in F is a number from K. We conjecture that |F| ⩽ (ns). We prove that our conjecturer is true for any K. (with min ki ⩾ s) when L = {0,1,…,s − 1}. We also show that for any K and any L, (with min ki > max lj)CALLING STATEMENT : © 1995 John Wiley & Sons, Inc.
An inequality involving the vertex arboricity and edge arboricity of a graph
Authors: Burr Stefan A. 
Published: June 2007

AbstractLet a(G) and a1(G) denote the vertex arboricity and the edge arboricity of G, respectively. The inequality a(G) ⩽ a1(G) is proved, and this is sharp. Two related inequalities, involving another parameter, are also proved.
Minimal ordered triangulations of surfaces
Authors: Magajna Zlatan , Mohar Bojan , Pisanski Tomaž 
Published: June 2007

AbstractA finite simplicial complex is orderable if its simplices are the chains of a poset. For each closed surface an orderable triangulation is given that is minimal with respect to the number of vertices. The construction of minimal ordered triangulations implies that for each surface S the minimal number of vertices of a bipartite graph, which has a quadrilateral embedding into S, is equal to b(S) = ⌈4 + (16 – 8χ)1/2⌉, where χ is the Euler characteristic of S.
Extremal problems concerning transformations of the edges of the complete hypergraphs
Authors: Caro Yair 
Published: June 2007

AbstractWe consider extremal problems concerning transformations of the edges of complete hypergraphs. We estimate the order of the largest subhypergraph K such that for every edge e ϵ E(K), f(e) ∉ E(K), assuming f(e) ≠ e. Several extensions and variations of this problem are also discussed here.
Edge‐colored saturated graphs
Authors: Hanson D. , Toft B. 
Published: June 2007

AbstractA graph G is (k1, k2, …, kt)‐saturated if there exists a coloring C of the edges of G in t colors 1, 2, …, t in such a way that there is no monochromatic complete ki‐subgraph K of color i, 1 ⩽ i ⩽ t, but the addition of any new edge of color i, joining two nonadjacent vertices in G, with C, creates a monochromatic K of color i, 1 ⩽ i ⩽ t. We determine the maximum and minimum number of edges in such graphs and characterize the unique extremal graphs.
Hierarchy for imbedding‐distribution invariants of a graph
Authors: Gross Jonathan L. , Furst Merrick L. 
Published: June 2007

AbstractMost existing papers about graph imbeddings are concerned with the determination of minimum genus, and various others have been devoted to maximum genus or to highly symmetric imbeddings of special graphs. An entirely different viewpoint is now presented in which one seeks distributional information about the huge family of all cellular imbeddings of a graph into all closed surfaces, instead of focusing on just one imbedding or on the existence of imbeddings into just one surface. The distribution of imbeddings admits a hierarchically ordered class of computable invariants, each of which partitions the set of all graphs into much finer subcategories than the subcategories corresponding to minimum genus or to any other single imbedding surface. Quite low in this hierarchy are invariants such as the average genus, taken over all cellular imbeddings, and the average region size, where “region size” means the number of edge traversals required to complete a tour of a region boundary. Further up in the hierarchy is the multiset of duals of a graph. At an intermediate level are the “imbedding polynomials.” The hierarchy is explored, and several specific calculations of the values of some of the invariants are provided. The main results are concerned with the amount of work needed to derive one invariant from another, when possible, and with principles for computing the algebraic effect of adding an edge or of otherwise combining two graphs.
On the Interval Number of a Triangulated Graph
Authors: Andreae Thomas 
Published: June 2007

AbstractThe interval number of a simple undirected graph G, denoted i(G), is the least nonnegative integer r for which we can assign to each vertex in G a collection of at most r intervals on the real line such that two distinct vertices v and w of G are adjacent if and only if some interval for v intersects some interval for w. For triangulated graphs G, we consider the problem of finding a sharp upper bound for the interval number of G in terms of its clique number ω(G). The following partial results are proved. (1) For each triangulated graph G, i(G) ⩽ ⌈ω(G)/2⌉ + 1, and this is best possible for 2 ⩽ ω(G) ⩽ 6. (2) For each integer m ⩾ 2, there exists a triangulated graph G with ω(G) = m and i(G) > m1/2.
Bidegreed graphs are edge reconstructible
Authors: Myrvold W. J. , Ellingham M. N. , Hoffman D. G. 
Published: June 2007

AbstractAn edge‐deleted subgraph of a graph G is a subgraph obtained from G by the deletion of an edge. The Edge Reconstruction Conjecture asserts that every simple finite graph with four or more edges is determined uniquely, up to isomorphism, by its collection of edge‐deleted subgraphs. A class of graphs is said to be edge reconstructible if there is no graph in the class with four or more edges that is not edge reconstructible. This paper proves that bidegreed graphs (graphs whose vertices all have one of two possible degrees) are edge reconstructible. The results are then generalized to show that all graphs that do not have three consecutive integers in their degree sequence are also edge reconstructible.
A new 5‐arc‐transitive cubic graph
Authors: Conder Marston 
Published: June 2007

AbstractA connected cubic graph having 75,600 vertices is shown to exist, with the symmetric group S10 as a group of automorphisms acting transitively on its 5‐arcs. This graph is not bipartite, nor is it a covering of any other known 4‐ or 5‐arc‐transitive graph.
Hypergraph planarity and the complexity of drawing venn diagrams
Authors: Johnson D. S. , Pollak H. O. 
Published: June 2007

AbstractWe introduce two new notions of planarity for hypergraphs based on dual generalizations of the standard Venn diagram. These definitions are illustrated by results concerning the existence and nonexistence of such diagrams for certain classes of hypergraphs. We conclude by showing that the general problem of determining whether such diagrams exist is NP‐complete.
On the hamiltonian path graph of a graph
Authors: Hendry George R. T. 
Published: June 2007

AbstractThe hamiltonian path graph H(F) of a graph F is that graph having the same vertex set as F and in which two vertices u and v are adjacent if and only if F contains a hamiltonian u − v path. First, in response to a conjecture of Chartrand, Kapoor and Nordhaus, a characterization of nonhamiltonian graphs isomorphic to their hamiltonian path graphs is presented. Next, the maximum size of a hamiltonian graph F of given order such that K̄d ⊆ H(F) is determined. Finally, it is shown that if the degree sum of the endvertices of a hamiltonian path in a graph F with at least five vertices is at least |V(F)| + t(t ⩾ 0), then H(F) contains a complete subgraph of order t + 4.
The maximum interval number of graphs with given genus
Authors: Scheinerman Edward R. 
Published: June 2007

AbstractThe interval number of a graph G, denoted i(G), is the least positive integer t such that G is the intersection graph of sets, each of which is the union of t compact real intervals. It is known that every planar graph has interval number at most 3 and that this result is best possible. We investigate the maximum value of the interval number for graphs with higher genus and show that the maximum value of the interval number of graphs with genus g is between ⌈√g⌉ and 3 + ⌈√3g⌉. We also show that the maximum arboricity of graphs with genus g is either 1 + ⌈√3g⌉ or 2 + ⌈√3g⌉.
On unavoidable digraphs in orientations of graphs
Authors: Bloom Gary S. , Burr Stefan A. 
Published: June 2007

AbstractLet G be a graph, and let D be a directed graph. Write G → D to mean that, no matter how the edges of G are given orientations, a copy of D must appear as a subgraph of the resulting oriented graph. It is proved that among all G for which G → D, the minimum chromatic number is equal to the minimum k for which Kk → hom(D), where hom(D) is the set of homomorphs of D. Next, necessary and sufficient conditions are given for a directed graph to have a homomorphism into a given transitive tournament, directed path, or directed cycle. These results are then applied to various cases of the above theorem. In particular, the minimum chromatic number is evaluated whenever D is an oriented forest, and all D are characterized for which the minimum chromatic number is no more than three.
Enumeration and generation of a class of regular digraphs
Authors: Ramanath M. V. S. , Walsh T. R. 
Published: June 2007

AbstractWe study the class of directed graphs that have indegree = outdegree = 2 at every vertex. These digraphs can be decomposed uniquely into “alternating cycles”, we use this decomposition to present efficient techniques for counting and generating them. The number (up to isomorphism) of these digraphs and the number of connected ones on up to 20 vertices have been computed and are presented.
Ki‐covers. II. Ki‐perfect graphs
Authors: Conforti Michele , Corneil Derek Gordon , Mahjoub Ali Ridha 
Published: June 2007

AbstractAKi is a complete subgraph of size i. A Ki‐cover of a graph G(V, E) is a set C of Ki−1s of G such that every Ki in G contains at least one Ki−1 in C. ci(G) is the cardinality of a smallest Ki‐cover of G. A Ki‐packing of G is a set of Kis such that no two Kis have i − 1 nodes in common. pi(G) is the cardinality of a largest Ki‐packing of G. Let Fi(G) denote the set of Kis in G and define ci(F) and pi(F) analogously for F ⊆ Fi(G). G is Ki‐perfect if ∀F ⊆ Fi(G), ci(F) = pi(F). The K2‐perfect graphs are precisely the bipartite graphs. We present a characterization of Ki‐perfect graphs that is similar to the Strong Perfect Graph Conjecture, and explore the relationships between Ki‐perfect graphs and normal hypergraphs. Furthermore, if iA denotes the 0 − 1 matrix of G where the rows are the elements of Fi−1(G) that belong to at least one Ki and the columns are the elements of Fi(G), then we show that iA is perfect iff G is a Ki‐perfect graph. We also characterize the Ki‐perfect graphs for which iAis balanced.