bluuebunny/crossref_metadata_2025_split huggingface dataset:
A LAN emulation model for wireless ATM
Authors: Hać Anna , Hossain Asif 
Published: August 2002

AbstractAn architecture based on emulated LAN is proposed which can efficiently provide the required bandwidth of mobiles as they migrate between cells. The proposed solution (1) ensures the required bandwidth of a mobile when its path changes because of handoff, (2) efficiently reserves bandwidth resulting in higher bandwidth/network utilization, (3) has the flexibility of reserving bandwidth depending upon the mobility (rate of handoff). Copyright © 2001 John Wiley & Sons, Ltd.
A new approach of polling efficiency based on network topology
Authors: Han Jeong‐Soo , Ahn Seong‐Jin , Chung Jin‐Wook 
Published: August 2002

AbstractIn this article we present significantly effective algorithms which allow the manager who already knows failure in one system or more in the managed network to choose which to manage. Using this information, we compare and analyze management efficiency affected by whether we are fully aware of the network topology or not, and carry out an experiment to generalize efficiency according to the location(s) of failed system(s). Copyright © 2001 John Wiley & Sons, Ltd.
Resource allocation scheme for QoS provisioning in microcellular networks carrying multimedia traffic
Authors: Hać Anna , Armstrong Abhinay 
Published: August 2002

AbstractWe propose a new resource allocation scheme based on the concept of resource reservation and resource renegotiation. The new scheme is aimed at improving performance with regard to new call blocking rate, handoff dropping rate, forced call termination rate, and average bandwidth use. We compare our scheme with other schemes. The performance is evaluated by using simulation. Copyright © 2001 John Wiley & Sons, Ltd.
ARCMA—adaptive request channel multiple access protocol for wireless ATM networks
Authors: Hać Anna , Chew Boon Ling 
Published: August 2002

AbstractWe propose a new multiple access protocol based on demand assignment. This protocol is designed to reduce contention in the request phase while minimizing transmission delay under various network (ATM) environments. Our protocol uses an adaptive scheme that changes under heavy traffic conditions, and also provides priority to certain delay‐sensitive traffic. Copyright © 2001 John Wiley & Sons, Ltd.
On multiroute maximum flows in networks
Authors: Aggarwal Charu C. , Orlin James B. 
Published: August 2002

AbstractLet G = (N, A) be a network with a designated source node s, a designated sink node t, and a finite integral capacity uij on each arc (i, j) ∈ A. An elementary K‐flow is a flow of K units from s to t such that the flow on each arcis 0 or 1. A K‐route flow is a flow from s to t that may be expressed as a nonnegative linear sum of elementary K‐flows. In this paper, we show how to determine a maximum K‐route flow as a sequence of O(min {log (nU), K}( maximum‐flow problems. This improves upon the algorithm by Kishimoto, which solves this problem as a sequence of K maximum‐flow problems. In addition, we have simplified and extended some of the basic theory. We also discuss the application of our technique to Birkhoff's theorem and a scheduling problem. © 2001 John Wiley & Sons, Inc.
Degree‐ and time‐constrained broadcast networks
Authors: Dinneen Michael J. , Pritchard Geoffrey , Wilson Mark C. 
Published: August 2002

AbstractWe consider the problem of constructing networks with as many nodes as possible, subject to upper bounds on the degree and broadcast time. This paper includes the results of an extensive empirical study of broadcasting in small regular graphs using a stochastic search algorithm to approximate the broadcast time. Significant improvements on known results are obtained for cubic broadcast networks. © 2002 Wiley Periodicals, Inc.
Efficient algorithms for centers and medians in interval and circular‐arc graphs
Authors: Bespamyatnikh Sergei , Bhattacharya Binay , Keil Mark , Kirkpatrick David , Segal Michael 
Published: August 2002

AbstractThep‐center problem is to locatepfacilities on a network so as to minimize the largest distance from a demand point to its nearest facility. Thep‐median problem is to locatepfacilities on a network so as to minimize the average distance from a demand point to its closest facility. We consider these problems when the network can be modeled by an interval or circular‐arc graph whose edges have unit lengths. We provide, given the interval model of annvertex interval graph, anO(n) time algorithm for the 1‐median problem on the interval graph. We also show how to solve thep‐median problem, for arbitraryp, on an interval graph inO(pnlogn) time and on a circular‐arc graph inO(pn2logn) time. We introduce a spring representation of the objective function and show how to solve thep‐center problem on a circular‐arc graph inO(pn) time, assuming that the arc endpoints are sorted. © 2002 Wiley Periodicals, Inc.
Multigraph augmentation under biconnectivity and general edge‐connectivity requirements
Authors: Ishii Toshimasa , Nagamochi Hiroshi , Ibaraki Toshihide 
Published: August 2002

AbstractGiven an undirected multigraphG= (V,E) and a requirement functionrλ: () →Z+(where () is the set of all pairs of vertices andZ+is the set of nonnegative integers), we consider the problem of augmentingGby the smallest number of new edges so that the local edge‐connectivity and vertex‐connectivity between every pairx,y∈Vbecome at leastrλ(x,y) and two, respectively. In this paper, we show that the problem can be solved inO(n3(m+n) log(n2/(m+n))) time, wherenandmare the numbers of vertices and pairs of adjacent vertices inG, respectively. This time complexity can be improved toO((nm+n2logn) logn), in the case of the uniform requirementrλ(x,y)= 𝓁 for allx,y∈V. Furthermore, for the generalrλ, we show that the augmentation problem that preserves the simplicity of the resulting graph can be solved in polynomial time for any fixed 𝓁*= max{rλ(x,y) |x,y∈V}. © 2001 John Wiley & Sons, Inc.
Minimum spanners of butterfly graphs
Authors: Hwang Shien‐Ching , Chen Gen‐Huey 
Published: August 2002

AbstractGiven a connected graphG, a spanning subgraphG′ofGis called at‐spanner if every pair of two adjacent vertices inGhas a distance of at mosttinG′. At‐spanner of a graphGis minimum if it contains minimum number of edges among allt‐spanners ofG. Finding minimum spanners for general graphs is rather difficult. Most of previous results were obtained for some particular graphs, for example, butterfly graphs, cube‐connected cycles, de Bruijn graphs, Kautz graphs, complete bipartite graphs, and permutation graphs. The butterfly graphs were originally introduced as the underlying graphs of FFT networks which can perform the fast Fourier transform (FFT) very efficiently. In this paper, we successfully construct most of the minimumt‐spanners for thek‐aryr‐dimensional butterfly graphs for 2 ≤t≤ 6 andt= 8. © 2001 John Wiley & Sons, Inc.
The structured total least‐squares approach for non‐linearly structured matrices
Authors: Lemmerling P. , Van Huffel S. , De Moor B. 
Published: August 2002

AbstractIn this paper, an extension of the structured total least‐squares (STLS) approach fornon‐linearly structuredmatrices is presented in the so‐called ‘Riemannian singular value decomposition’ (RiSVD) framework. It is shown that this type of STLS problem can be solved by solving a set of Riemannian SVD equations. For small perturbations the problem can be reformulated into finding the smallest singular value and the corresponding right singular vector of this Riemannian SVD. A heuristic algorithm is proposed. Some examples of Vandermonde‐type matrices are used to demonstrate the improved accuracy of the obtained parameter estimator when compared to other methods such as least squares (LS) or total least squares (TLS). Copyright © 2002 John Wiley & Sons, Ltd.
A numerical method for the determination of dextrous workspaces of Gough–Stewart platforms
Authors: du Plessis L. J. , Snyman J. A. 
Published: August 2002

AbstractAn optimization approach to the computation of the boundaries of different dextrous workspaces of parallel manipulators is presented. A specific dextrous workspace is the region in space in which, at each position of the working point, a manipulator can control the orientation of its upper working platform through a specified range of orientation angles. Here the dextrous workspace is determined from the intersection of suitably chosen fixed orientation workspaces, which are found by application of a constrained optimization algorithm. The procedure is simple and has the considerable advantage that it may easily be automated. The method is illustrated by its application to both a planar and spatial Gough–Stewart platform. Copyright © 2001 John Wiley & Sons, Ltd.
Real qualitative researchers do not count: The use of numbers in qualitative research
Authors: Sandelowski Margarete 
Published: August 2002

AbstractTwo myths about qualitative research are that real qualitative researchers do not count and cannot count. These antinumber myths have led to the underutilization of numbers in qualitative research and to the simplistic view of qualitative research as non‐ or antinumber. Yet numbers are integral to qualitative research, as meaning depends, in part, on number. As in quantitative research, numbers are used in qualitative research to establish the significance of a research project, to document what is known about a problem, and to describe a sample. But they are also useful for showcasing the labor and complexity of qualitative work and to generate meaning from qualitative data; to document, verify, and test researcher interpretations or conclusions; and to re‐present target events and experiences. Although numbers are important in the treatment of qualitative data, qualitative researchers should avoid the counting pitfalls of verbal counting, overcounting, misleading counting, and acontextual counting. © 2001 John Wiley & Sons, Inc. Res Nurs Health 24: 230–240, 2001
State reform and the ‘privatized state’ in Paraguay
Authors: Nickson Andrew , Lambert Peter 
Published: August 2002

AbstractThis article uses Paraguay, in Latin America, as a case study in order to examine the difficulties of introducing state reform where the state itself has a long history of control by private interests. It shows how the ‘privatized’ nature of the Paraguayan state is central to an understanding of how it has functioned and responded to recent reform efforts. The article provides an overview of the Paraguayan public sector and identifies several of its peculiar features that are relevant to understanding the state reform process: its small size, high levels of inefficiency and ineffectiveness, rampant politicization and endemic corruption. The article examines the three major components of an externally driven state reform process that began with democratization in 1989: privatization of loss‐making state corporations, civil service reform and decentralization. It shows how the ‘privatized’ nature of the state has proved a major obstacle to these efforts and is a major factor in explaining their limited success. The article concludes by offering a pessimistic assessment of the likely prospects for state reform and highlights the danger that Paraguay could descend into a ‘failed state’. Copyright © 2002 John Wiley & Sons, Ltd.
Benchmarking: a tool for facilitating organizational learning?
Authors: Auluck Randhir 
Published: August 2002

AbstractThis article looks at benchmarking as a tool for promoting performance improvement and the ‘learning organization’ ideal. Specifically, it considers some of the ways the European Foundation for Quality Management Excellence Model and self‐assessment approach are being applied within the UK public service. Further, the article introduces ‘Dolphin’, a new self‐assessment tool based on the Excellence Model, and describes how the tool can be applied in practice. Finally, whether benchmarking can aid organizational improvement, organizational learning and establish the basis for a ‘learning culture’ is discussed. Copyright © Crown Copyright 2002. Recorded with the permission of the controller of Her Majestry's Stationery Office. Published by John Wiley & Sons, Ltd.
Critical aspects for the reliable headspace analysis of plants cultivated in vitro
Authors: Maes Katrien , Vercammen Joeri , Pham‐Tuan Hai , Sandra Pat , Debergh Pierre C. 
Published: August 2002

AbstractVarious factors controlling the recoveries of volatile organic compounds in in vitro headspace analysis of tomato plants (Lycopersicon esculentum Mill. ‘Moneymaker’), sampled using solid phase micro‐extraction, were evaluated and optimised. The variations in composition of the headspaces were determined as a function of time, and following in vitro wounding of the plant. Copyright © 2001 John Wiley & Sons, Ltd.
Population screening for isoniazid acetylator phenotype
Authors: Seifart Heiner I. , Parkin Donald P. , Botha Frederik J. H. , Donald Peter R. , Van Der Walt Ben J. 
Published: August 2002

AbstractPurposeTo establish a useful method for acetylator phenotypification and therapeutic drug monitoring of patients receiving isoniazid.MethodsSixty patients with uncomplicated pulmonary tuberculosis were given a 5‐mg/kg oral dose of isoniazid each. Plasma concentrations of isoniazid and its metabolite, acetyl‐isoniazid, were determined by HPLC analyses at various post‐dose times. From the isoniazid concentration and the concentration ratio of acetyl‐isoniazid and isoniazid (metabolic ratio), phenotypification methods were assessed.ResultsThe metabolic ratios at 3 h post‐dose revealed a trimodal distribution; a fast, intermediate and slow acetylator phenotype group. The 2‐h and 6‐h data showed different bimodal combinations of these phenotype groups. The metabolic ratio phenotypification method could be simplified by using the HPLC data directly without converting it to absolute concentrations.ConclusionsA single‐sample test based upon the plasma isoniazid concentration, combined with the metabolic ratio of acetyl‐isoniazid and isoniazid, appears to be a reliable parameter for phenotype discrimination and for bioavailability testing. Copyright © 2001 John Wiley & Sons, Ltd.
Living free‐radical polymerization of styrene under a constant source of γ radiation
Authors: Quinn John F. , Barner Leonie , Rizzardo Ezio , Davis Thomas P. 
Published: August 2002

AbstractLiving polymerization of styrene was observed using γ radiation as a source of initiation and 1‐phenylethyl phenyldithioacetate as a reversible addition–fragmentation chain transfer (RAFT) agent. The γ radiation had little or no detrimental effect on the RAFT agent, with the molecular weight of the polymer increasing linearly with conversion (up to the maximum measured conversions of 30%). The polymerization had kinetics (polym.) consistent with those of a living polymerization (first order in monomer) and proportional to the square root of the radiation‐dose rate. This initiation technique may facilitate the grafting of narrow polydispersity, well‐defined polymers onto existing polymer surfaces as well as allow a wealth of kinetic experiments using the constant radical flux generated by γ radiation. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 19–25, 2002
Preparation of partially hydrolyzed oligo(vinylacetate) as polyol for polyurethane formation
Authors: Zimmermann Jörg , Sunder Alexander , Mülhaupt Rolf 
Published: August 2002

AbstractPolyols based on oligo(vinylacetate) were synthesized using a convenient one‐pot, two‐step process. Polymerization of vinylacetate was performed in 2‐propanol as a chain‐transfer agent using di‐tert‐butylperoxide as a free‐radical initiator. Saponification of the oligomers was performed in both tetrahydrofuran and 2‐propanol using stoichiometric amounts of methanol in the presence of a basic catalyst. Well‐defined oligo(vinylacetate‐co‐vinylalcohol) polyols with a degree of polymerization below 12 and a hydroxyfunctionality smaller than 4 were obtained. Oligo(vinylacetate‐co‐vinylalcohol) was used as a polyol component in the formation of polyurethanes. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2085–2092, 2002
Polyurethanes containing sulfur. III. New thermoplastic HDI‐based segmented polyurethanes with diphenylmethane unit in their structure
Authors: Kultys Anna , Pikus Stanisław 
Published: August 2002

AbstractThree series of new thermoplastic, high molecular weight, segmented thiopolyurethanes were synthesized by a one‐step melt polymerization from newly obtained thiodiols, including bis[4‐(2‐hydroxyethyl)thiomethylphenyl]methane, bis[4‐(3‐hydroxypropyl)thiomethylphenyl]methane, and bis[4‐(6‐hydroxyhexyl)thiomethylphenyl]methane (BHHM), as chain extenders; hexamethylene diisocyanate; and 20–80 mol % poly(oxytetramethylene) glycol (PTMG; number‐average molecular weight = 1000) as the soft segment. Solution polymerization with the chain extender BHHM gave considerably lower molecular weight polymers. The structures of all the polyurethanes were determined with Fourier transform infrared and X‐ray diffraction analysis. The thermal properties of the polyurethanes were examined with differential scanning calorimetry and thermogravimetric analysis. Shore A/D hardness and tensile properties were also determined. All the polyurethanes showed partially crystalline structures; those obtained with 40–80 mol % PTMG were elastomers. An increase in the PTMG content decreased hardness, modulus of elasticity, and tensile strength, whereas elongation at break increased. BHHM‐based polyurethanes obtained in the melt showed the best tensile properties. The polyurethanes exhibited definite glass transitions (−70 to −59 °C) that were nearly independent of the hard‐segment content up to about 50 wt % (40–80 mol % PTMG), indicating the existence of mainly microphase‐separated soft and hard segments. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1733–1742, 2001
Polyrotaxanes by free‐radical polymerization of acrylate and methacrylate monomers in the presence of a crown ether
Authors: Gibson Harry W. , Bryant William S. , Lee Sang‐Hun 
Published: August 2002

AbstractPoly[(methyl acrylate)‐rotaxa‐(30‐crown‐10)] (5) and poly[(methyl methacrylate)‐rotaxa‐(30‐crown‐10)] (6) were synthesized by azobisisobutyronitrile‐initiated free‐radical bulk polymerizations of the respective monomers in the presence of 30‐crown‐10 (1; equimolar; 5 times the monomer mass). For 5, 3.8 mass % (0.81 mol % with respect to the monomer) of the crown was incorporated versus 1.7 mass % (0.39 mol % with respect to the monomer) for 6. Control reactions with 18‐crown‐6, which is to small to be threaded, showed that chain transfer to the crown ethers was detectable only for the acrylate but was relatively negligible and spectroscopically distinct. The threading yields were much higher with these systems than with polystyrene, most likely because of the greater compatibility of the crown ether with these polar monomers and polymers and the consequent ability to carry out the polymerizations homogeneously in the absence of added solvent; however, the threading process was still essentially statistical. Therefore, the polymerization of methacrylate monomers 8a–8c based on tetraarylmethane moieties connected via diethyleneoxy or triethyleneoxy spacers was examined in the presence of 1 in the belief that the supramolecular semirotaxane monomer 9 formed statistically in situ could be captured more efficiently and produce higher threading yields, presumably of side‐chain polyrotaxanes, than the simple (meth)acrylate monomers. Azobisisobutyronitrile‐initiated polymerizations either neat or in toluene produced polyrotaxanes 10 with up to about 1.6 mass % and 2 mol % threaded crown ether, presumably trapped on the pendant stoppered side chains. Although primarily statistical in nature, the latter rotaxane syntheses afforded on a molar basis 3–7 times more efficient incorporation of 1 than styrene (0.33 mol %), methyl acrylate (0.81 mol %), or methyl methacrylate (0.39 mol %) monomers for the preparation of main‐chain polypseudorotaxanes and indeed even surpassed the 60‐crown‐20/polyacrylonitrile system (1.5 mol %). This was presumed to be due to the fact that the loss of the crown ether, once it was threaded onto the monomer to form 9 and the latter was polymerized, was either retarded (by the tetraphenylmethyl stopper in 10a) or prevented completely [by tris(p‐t‐butylphenyl)phenylmethyl stoppers in 10b and 10c]. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1978–1993, 2001
Copolymerization behavior of direct polycondensation of AB2 and AB monomers that forms hyperbranched aromatic polyamide copolymers
Authors: Jikei Mitsutoshi , Fujii Ken , Kakimoto Masa‐Aki 
Published: August 2002

AbstractThe copolymerization behavior of the one‐step direct polycondensation of 3,5‐bis‐(4‐aminophenoxy)benzoic acid (AB2 monomer) and 3‐(4‐aminophenoxy)benzoic acid (AB monomer) was investigated by IR and 13C NMR measurements. IR measurements revealed that the content of the AB2 units in the polymer was higher in the early stages of polymerization. 13C NMR spectra of the polymers indicated that the number of dendritic units increased slowly with increasing reaction time. The stepwise copolymerization of the AB2 and AB monomers was also carried out, and the structure was analyzed by 13C NMR measurements. Copolymer synthesized stepwise by adding AB2 monomer first (polymer II) had more dendritic units and less terminal units as compared with the one‐step copolymer (polymer I). Copolymer synthesized stepwise by adding AB monomer first gave a resulting copolymer (polymer III) composed of long AB chains. The solubility of the stepwise copolymers was low, and the inherent viscosity was high in comparison with the one‐step copolymer as a result of the difference in architecture of the copolymers. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3304–3310, 2001
Reversible melting in nanophase‐separated poly(oligoamide‐alt‐oligoether)s and its dependence on sequence length, crystal perfection, and molecular mobility
Authors: Di Lorenzo Maria Laura , Pyda Marek , Wunderlich Bernhard 
Published: August 2002

AbstractThe degree of reversibility of the melting of multiblock copolymers of alternating oligoamides and oligoethers was investigated with respect to the composition and molecular mass of the blocks. The analysis was conducted with temperature‐modulated calorimetry, and it revealed different degrees of reversibility of the melting process that depended on the block length, crystal perfection, and molecular mobility. For the oligoamide blocks, the amount of crystal that melts and crystallizes reversibly during quasi‐isothermal analysis increases with decreasing molar mass, and shorter amide sequences form poorer crystals that have a higher tendency toward reorganization. Reorganization of the oligoamides is also favored by the presence of the more mobile oligoether units. Reversible melting of the oligoether segments is influenced by the presence of glassy and crystalline oligoamide blocks in the adjacent nanophases. Because of the segmented nature of the copolymers, the oligoether segments are not free to flow as in an isotropic melt but are anchored to the oligoamide surfaces with different degrees of restriction that change the local equilibrium of melting and recrystallization. A comparison of the copolymers with the corresponding homopolymers provides information about the role of molecular nucleation and mobility in the reversibility of melting. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2969–2981, 2001