bluuebunny/crossref_metadata_2025_split huggingface dataset:
An interactive approach to multiple criteria optimization with multiple decision‐makers
Authors: Korhonen Pekka , Moskowitz Herbert , Wallenius Jyrki , Zionts Stanley 
Published: May 2007

AbstractIn this article we propose a formal man‐machine interactive approach to multiple criteria optimization with multiple decision makers. The approach is based on some of our earlier research findings in multiple criteria decision making. A discrete decision space is assumed. The same framework may readily be used for multiple criteria mathematical programming problems. To test the approach two experiments were conducted using undergraduate Business School students as subjects in Finland and in the United States. The context was, respectively, a high‐level Finnish labor‐management problem and the management‐union collective bargaining game developed at the Krannert Graduate School of Management, Purdue University. The results of the experiments indicate that our approach is a potentially useful decision aid for group decision‐making and bargaining problems.
A heuristic for capacity expansion planning with multiple facility types
Authors: Luss Hanan 
Published: May 2007

AbstractA capacity expansion model with multiple facility types is examined, where different facility types represent different quality levels. Applications for the model can be found in communications networks and production facilities. The model assumes a finite number of discrete time periods. The facilities are expanded over time. Capacity of a high‐quality facility can be converted to satisfy demand for a lower‐quality facility. The costs considered include capacity expansion costs and excess capacity holding costs. All cost functions are nondecreasing and concave. An algorithm that finds optimal expansion policies requires extensive computations and is practical only for small scale problems. Here, we develop a heuristic that employs so‐called distributed expansion policies. It also attempts to decompose the problem into several smaller problems solved independently. The heuristic is computationally efficient. Further, it has consistently found near‐optimal solutions.
Bounding methods for facilities location algorithms
Authors: Dowling Paul D. , Love Robert F. 
Published: May 2007

AbstractSingle‐ and multi‐facility location problems are often solved with iterative computational procedures. Although these procedures have proven to converage, in practice it is desirable to be able to compute a lower bound on the objective function at each iteration. This enables the user to stop the iterative process when the objective function is within a prespecified tolerance of the optimum value. In this article we generalize a new bounding method to include multi‐facility problems with lp distances. A proof is given that for Euclidean distance problems the new bounding procedure is superior to two other known methods. Numerical results are given for the three methods.
The processor‐sharing queueing model for time‐shared systems with bulk arrivals
Authors: Kleinrock L. , Muntz R. R. , Rodemich E. 
Published: May 2007

AbstractWe consider a model which is applicable to time‐multi‐plexed systems, such as multiplexed communication channels and time‐shared computing facilities. In this (processor‐sharing) queueing model, all jobs currently in the system share equally the processing capability of the server. In this paper, we investigate the processor‐sharing model for the case of bulk arrivals. The mean response time of the system as a function of required service time is derived. An example is given to show the effect of bulk arrivals versus single arrivals for a constant utilization.
Optimal design of centralized computer networks
Authors: Frank H. , Frisch I. T. , Van Slyke R. , Chou W. S. 
Published: May 2007

AbstractMajor design problems for centralized computer networks are link layout and capacity assignment. The objective is to select link locations and capacities so that the average time delay required to transmit a message from any node to the central node does not exceed a specified maximum. The design problem is to find the least cost system which satisfies the time delay constraints for given levels of traffic. In this paper, we describe an algorithm to select globally optimum link capacities for specified tree structures. We also give a heuristic method for finding low cost tree structures. The methods have been programmed and are capable of handling networks with thousands of nodes. In addition, they can consider any finite set of link capacities with an arbitrary cost structure and do not depend on the mathematical model used to calculate average time delay.
An algorithm for certain multi‐commodity flow problems
Authors: Kleitman Daniel J. 
Published: May 2007

AbstractIn this paper an algorithm is presented for solving a certain class of multi‐commodity flow problems. The class of problems considered consist of integer capacity multi‐source and multi‐sink problems for which each node is a source of sink for all but at most one commodity. The algorithm is described in the case that any edge connecting a source and sink of a commodity can be used for flow of that commodity.
Minimal k‐arc connected graphs
Authors: Fulkerson D. R. , Shapley L. S. 
Published: May 2007

AbstractA graph is k‐arc‐connected if it is necessary to remove at least k arcs in order to disconnect the graph. This paper solves the problem of determining the least number of arcs required in a k‐arc‐connected graph on n nodes by describing constructions that produce such graphs having kn/2 arcs (for kn éven) or (kn+1) /2 arcs (for kn odd). These results have application to the practical problem of synthesizing minimum cost, “k‐reliable” communication networks.
The steiner problem in graphs
Authors: Dreyfus S. E. , Wagner R. A. 
Published: May 2007

AbstractAn algorithm for solving the Steiner problem on a finite undirected graph is presented. This algorithm computes the set of graph arcs of minimum total length needed to connect a specified set of k graph nodes. If the entire graph contains n nodes, the algorithm requires time proportional to
n3/2 + n2 (2k‐1 ‐ k ‐ 1) + n(3k‐1 ‐ 2k + 3)/2.The time requirement above includes the term n3/2, which can be eliminated if the set of shortest paths connecting each pair of nodes in the graph is available.
Network reliability analysis: Part I
Authors: Van Slyke R. , Frank H. 
Published: May 2007

AbstractThis paper considers networks with randomly failing links and nodes. In Part 1, nodes are assumed to be perfectly reliable. A combinatorial analysis is given when all links have equal reliabilities. Two general simulation methods are described. The first is particularly useful if a wide range of failure probabilities is to be considered. The second combines a combinatorial analysis with stratified sampling to yield major computational savings. Later parts will describe generalizations, decomposition methods for large networks and applications to computer network analysis.
On non‐blocking switching networks
Authors: Cantor D. G. 
Published: May 2007

AbstractA switching network may be informally described as a collection of single‐pole, single‐throw switches arranged so as to connect a set of terminals called inputs to another set of terminals called outputs. It is non‐blocking if, given any set of connections from some of the inputs to some of the outputs, and an idle input terminal x and idle output terminal y, then it is possible to connect x to y without disturbing any of the existing connections. Denote by σ(a, b) the minimal number of switches necessary to connect a inputs to b outputs using a non‐blocking network. We are interested in studying the growth of σ(a, a) as a → ∞. Results of C. Clos show that σ(a, a) ⩽ C ae2√log a·log 2. We show that σ(a, a) ⩽ 8a(log2a)2.
Bounded color functions on graphs
Authors: Matula D. W. 
Published: May 2007

AbstractThe maximum edge‐connectivity of any subgraph plus unity is shown to be an upper bound on the chromatic number for any graph. More generally it is shown that every graph possesses a Grundy function bounded at each vertex by the maximum edge‐connectivity of the subgraphs containing that vertex. A discussion of how to construct such a Grundy function is also provided.
Computer communication network design: Experience with theory and practice
Authors: Frank H. , Kahn R. E. , Kleinrock L. 
Published: May 2007

AbstractThe design of the ARPA Computer Network brought together many individuals with diverse backgrounds and philosophies. In this paper, we review the methods used in the design of the Network from the vantage of over two years' experience in its development. The design variables, system constraints, and performance criteria for the network are discussed along with an evaluation of the tools used to design an efficient and reliable system. The design procedures and the conclusions reached about the network's properties appear to be generally applicable to message switched networks. Consequently, the results of this paper should be useful in the design and study of other store‐and‐forward computer communication networks.
Generalized multi‐stage connection networks
Authors: Masson G. M. , Jordan B. W. 
Published: May 2007

AbstractThis paper develops multi‐stage connection networks in which each input terminal can be connected to any number of output terminals. Conditions are given such that these networks are strictly nonblocking or are rearrangeable. Rearrangement algorithms and upper bounds on the required number of moves are developed and it is shown that such networks have fewer cross‐points than the product of input and output terminals for a sufficiently large number of input and output terminals.
A general class of invulnerable graphs
Authors: Boesch F. T. , Felzer A. P. 
Published: May 2007

AbstractThe idea of utilizing the connectivity properties of a graph as measures of its vulnerability has been well documented. The graph theoretic concepts and the basic results of this theory are reviewed here. Various types of optimally invulnerable graphs are defined and compared.New results are presented for the synthesis of optimal graphs. Specifically a class of graphs called telescopically non‐contracting star polygons are shown to constitute a rather general set of invulnerable graphs. This new class extends the set of known optimal graphs considerably.
On the equivalence of optimality criterion and sequential approximate optimization methods in the classical topology layout problem
Authors: Groenwold Albert A. , Etman L. F. P. 
Published: May 2007

AbstractWe study the ‘classical’ topology optimization problem, in which minimum compliance is sought, subject to linear constraints. Using a dual statement, we propose two separable and strictly convex subproblems for use in sequential approximate optimization (SAO) algorithms.Respectively, the subproblems use reciprocal and exponential intermediate variables in approximating the non‐linear compliance objective function. Any number of linear constraints (or linearly approximated constraints) are provided for. The relationships
between the primal variables and the dual variables are found in analytical form.For the special case when only a single linear constraint on volume is present, we note that application of the ever‐popular optimality criterion (OC) method to the topology optimization problem, combined with arbitrary values for the heuristic numerical damping factor η proposed by Bendsøe, results in an updating scheme for the design variables that is identical to the application of a rudimentary dual SAO algorithm, in which the subproblems are based on exponential intermediate variables. What is more, we show that the popular choice for the damping factor η=0.5 is identical to the use of SAO with reciprocal intervening variables.Finally, computational experiments reveal that subproblems based on exponential intervening variables result in improved efficiency and accuracy, when compared to SAO subproblems based on reciprocal intermediate variables (and hence, the heuristic topology OC method hitherto used). This is attributed to the fact that a different exponent is computed for each design variable in the two‐point exponential approximation we have used, using gradient information at the previously visited point. Copyright © 2007 John Wiley & Sons, Ltd.
Adaptive mesh technique for thermal–metallurgical numerical simulation of arc welding processes
Authors: Hamide M. , Massoni E. , Bellet M. 
Published: May 2007

AbstractA major problem arising in finite element analysis of welding is the long computer times required for a complete three‐dimensional analysis. In this study, an adaptative strategy for coupled thermometallurgical analysis of welding is proposed and applied in order to provide accurate results in a minimum computer time. The anisotropic adaptation procedure is controlled by a directional error estimator based on local interpolation error and recovery of the second derivatives of different fields involved in the finite element calculation. The methodology is applied to the simulation of a gas–tungsten‐arc fusion line processed on a steel plate. The temperature field and the phase distributions during the welding process are analyzed by the FEM method showing the benefits of dynamic mesh adaptation. A significant increase in accuracy is obtained with a reduced computational effort. Copyright © 2007 John Wiley & Sons, Ltd.
Melt processing and characterization of multicomponent polymeric nanocomposites containing organoclay
Authors: Letuchi M. , Tzur A. , Tchoudakov R. , Narkis M. , Siegmann A. 
Published: May 2007

AbstractNylon 6 (Ny)/polypropylene (PP)/maleated polypropylene (PP‐g‐MA)/organoclay/wollastonite composites were prepared by melt processing. The polymers' composition was kept constant ([70PP/30Ny]/4PP‐g‐MA). Melt compounding was conducted using a twin‐screw extruder in three different methods: (1) simultaneous incorporation of the components into the compounding equipment, (2) preparation of [Ny6/clay] concentrate, and then in a second step, mixing the other components with the concentrate, and (3) mixing of PP with wollastonite and clay followed by the addition of Ny6 and PP‐g‐MA in the second step. Injection‐molded specimens were characterized in tension, scanning electron microscopy, X‐ray diffraction (XRD), and differential scanning calorimetry. The sequence of component addition greatly influences the structure and properties of the composites. Enhanced mechanical properties were achieved when the two‐step mixing procedure was used for the PP/Ny6/PP‐g‐MA/clay system (method 2) and also for the PP/Ny6/PP‐g‐MA/clay/wollastonite system (method 3). The XRD pattern of the PP/Ny6/PP‐g‐MA/clay nanocomposites produced by the two‐step mixing method does not show a characteristic basal reflection of the pristine organoclay, indicating a predominately exfoliated structure of clay. POLYM. COMPOS., 28:417–424, 2007. © 2007 Society of Plastics Engineers
Comparison of procedures for directly obtaining protected peptide acids from peptide‐resins
Authors: Proti Patrícia B. , Remuzgo César , Miranda M. Terêsa M. 
Published: May 2007

AbstractThe preparation of small‐sized protected peptide acids related to cholecystokinin and gomesin was attempted using peptide‐Kaiser oxime resins (KOR) as starting materials. For comparison, peptide‐2‐Cl‐trityl resin (CLTR) was also employed. While peptide detachment from KOR was achieved through the oxime ester bond hydrolysis mediated by DBU, hydroxide ion or Ca+2ion, peptide release from CLTR was accomplished through acid‐catalysed hydrolysis of the peptide‐resin ester linkage. Amino acid analysis of the peptide‐resins before and after peptide release allowed the calculation of the reaction yields. RP‐HPLC and LC/ESI‐MS of the resulting crude peptides allowed estimation of their quality. The data collected indicated that: (i) among the procedures used for peptide displacement from KOR, the one employing DBU was the most efficient since it furnished all model protected peptide acids with the highest quality in a very short time; (ii) although slow, Ca+2‐assisted peptide detachment from KOR was selective and was suitable for generating high‐quality protected peptide acids containing up to five residues; (iii) even though the protocols employed for peptide release from CLTR have shown to be appropriate, the one employing 1% TFA/DCM was the most productive; (iv) in terms of product quality, DBU‐catalysed peptide detachment from KOR was similar to TFA‐catalysed peptide release from CLTR although the latter was more productive. These findings are relevant to peptide chemists in general, but especially to those interested in preparing acyl donors for convergent peptide syntheses by the t‐Boc chemistry. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Investigation of zinc‐modified lead barium strontium zirconium niobium titanate solid solutions for tailored dielectric and ferroelectric properties
Authors: Ramam Koduri 
Published: May 2007

AbstractPolycrystalline solid solutions of [Pb1–x –y Bax Sry ][Zrz Ti1–z ]1–(5k /4)–(m /2)Nbk Znm O3 (PBSZZNT) substituted as [Pb0.973Ba0.015Sr0.012][Zr0.53Ti0.47]0.975–(m /2)Nb0.02Znm O3 where m = 0, 0.5, 1.0 and 1.5 mol% have been synthesized through a solid‐state reaction method and their dielectric and ferroelectric properties were investigated. X‐ray diffraction patterns indicated that all compositions exhibit a single ferroelectric tetragonal phase (FETET). The average grain growth increased to 1 mol% Zn (2.42 µm) while the density was promoted up to 1.5 mol% Zn (7.74 gm/cm3) doped PBSZNT ceramics, respectively. Dielectric studies reveal that the room‐temperature dielectric constant (εRT) decreased constantly while the Curie temperature (Tc) showed mixed behavior in Zn‐doped PBSZNT ceramics, respectively. The optimum ferroelectric properties were observed in 1 mol% Zn doped PBSZNT where both A‐site and B‐site modification was evidently enhanced (Pr = 33.12 µC/cm2 and Ps = 39.86 µC/cm2) with relatively decreasing coercive field. The influence of Zn‐modified compositions on the Ti‐rich region (Zr/Ti = 53/47) in PBSZNT ceramics showed significant variations that are discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Heavily‐branched macropore and single‐trench fabrication via breakdown mechanism
Authors: Bao X. Q. , Jiao J. W. , Wang Y. L. , Na K. W. , Choi H. 
Published: May 2007

AbstractUsually, etching of n‐type silicon in the dark produces “break down” mesopores. In this letter, by etching with aqueous and strong oxidizing electrolytes respectively, heavily branched macropores with diameters up to 4 μm and depths up to 200 μm were produced without illumination on low doped n‐type silicon. Isolated silicon islands were obtained due to the interconnection of the main pores. The heavily branched macropores on the micron scale could be filled with smooth macropores with diameters up to 500 nm. Due to a small primary length scale no more than 250 nm in their rather short nucleation phases, the main pores should be secondary macropores. Based on these findings, a single trench with long branches, which might facilitate potential applications, was fabricated with prestructured linear nuclei. Current‐burst‐model combined with breakdown mechanism was finally found to be responsible for the formation of heavily‐branched macropores. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Highly (100)‐oriented (Pb1–xLax)Ti1–x /4O3/Pb(Zr0.20Ti0.80)O3/(Pb1–xLax)Ti1–x /4O3 multilayered thin films by RF magnetron sputtering
Authors: Wu Jiagang , Xiao Dingquan , Zhu Jiliang , Zhu Jianguo , Tan Junzhe 
Published: May 2007

Abstract(Pb1–x Lax )Ti1–x /4O3/Pb(Zr0.20Ti0.80)O3/(Pb1–x Lax )Ti1–x /4O3 (x = 0, 0.10, 0.15, 0.20) [PLTx /PZT/PLTx ] multilayered thin films were in situ deposited on Pt(111)/Ti/SiO2/Si(100) substrates by a RF magnetron sputtering technique with a PbOx buffer layer. With this method, all the multilayered films possess highly (100) orientation. The PbOx buffer layer leads to the (100) orientation of the multilayered films; the double‐sided PLTx layers improve the electrical properties of the films. The effect of the La content in the PLTx layers on the dielectric and ferroelectric properties of the PZT thin films was investigated. The enhanced dielectric and ferroelectric properties are observed in the PLTx /PZT/PLTx (x = 0.10) multilayered films. The dielectric constant reaches a maximum value of 298 at 1 kHz for x = 0.10 with a low loss tangent of 0.0261; along with enhanced dielectric properties, the multilayered films also exhibit a large remanent polarization value of 2Pr = 58.6 μC/cm2. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hybrid nitride microcavity using crack‐free highly reflective AlN/GaN and Ta2O5/SiO2 distributed Bragg mirrors
Authors: Huang G. S. , Chen Hou‐Guang , Chen J.‐R. , Lu T. C. , Kuo H. C. , Wang S. C. 
Published: May 2007

AbstractWe report the growth over 2 inch sapphire substrates of hybrid nitride‐based microcavities using one crack‐free highly reflective AlN/GaN distributed Bragg reflectors (DBRs) incorporated with AlN/GaN superlattice (SL) insertion layers and Ta2O5/SiO2 DBRs. The optical cavity is formed by a 5λ cavity consisting of n‐type GaN, 10 pairs multiple quantum wells and p‐type GaN sandwiched by AlN/GaN and Ta2O5/SiO2 DBRs. Reflectivity and photoluminescence measurements were carried out on these structures. A 29 periods AlN/GaN DBR incorporated with six AlN/GaN superlattice insertion layers showed no observable cracks and achieved a peak reflectivity of 99.4% and a stopband of 21 nm. Based on these high quality DBRs, the cavity mode is clearly resolved with a linewidth of 2.6 nm. These results demonstrate that the AlN/GaN system is very promising for the achievement of strong light–matter interaction and the fabrication of nitride‐based vertical cavity surface emitting lasers. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
How it really happened: The history of p‐type doping of gallium nitride
Authors: Jain Rakesh B. , Maruska Herbert Paul 
Published: May 2007

AbstractThe first single crystal thin film layers of gallium nitride (GaN) were grown in 1969, but it was not until 1989 that conducting p‐type films of GaN were finally achieved. Many unsuccessful attempts to produce p‐type GaN by annealing techniques including thermal and electron beam annealing were attempted in those intervening twenty years. We discuss here the reason for the early failures, and how the problems were overcome. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)Communicate your viewphysica status solidi welcomes correspondence related to the articles in its new Historical Review section. If you wish to comment on the developments and topics recounted here from your own perspective, please send an e‐mail to the editor at pss@wiley-vch.de. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical spectroscopy study of Cr3+ ion in NaMg3Al(MoO4)5 crystal
Authors: Hermanowicz K. 
Published: May 2007

AbstractElectron absorption, excitation and emission spectra have been measured for Cr3+ ion‐doped NaMg3Al(MoO4)5 crystal in the temperature range from 9 to 300 K. The sharp lines of the 2E–4T2 emission and broadband 4T2–4A2 luminescence from strong and weak crystal field Cr3+ sites as well as their temperature dependencies were observed. Below 200 K, Cr3+ ion pairs are detected. The local structure of Cr3+ surroundings is discussed in terms of the spectroscopic results and the crystal field parameters Dq, B and C of the Cr3+ ion are derived. The Huang–Rhys, S, and breathing phonons, ħω, parameters are reported. The use of the studied crystal as a laser material is briefly analyzed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)