Showing papers in "Scopus in 2002"

Study of traffic statistics of assembled burst traffic in optical burst-switched networks

Abstract: Optical Burst Switching (OBS) is considered as a promising switching technique for building the next generation optical Internet. In OBS networks, one important issue is how the performance will be affected by bursts assembled from packets, which is the basic transmission unit in OBS. In this paper, we study the fundamental statistic properties such as the burst length distribution, inter-arrival time distribution, as well as correlation structure of assembled burst traffic from burst assembly algorithms. From both theoretical and empirical results, it is demonstrated that after the assembly, the traffic will in general approach the Gaussian distribution. In particular, the variance of assembled traffic decreases with the increase in the assembly window size and the traffic load. However, the long range dependence in the input traffic will not change after assembly. Such smoothed assembled traffic will enhance the OBS performance by reducing burst loss and increase OBS throughput. This result is useful for the future study of OBS node and networks.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Split TCP for mobile ad hoc networks

Abstract: The fairness and throughput of TCP suffer when it is used in mobile ad hoc networks. This is because TCP wrongly attributes packet losses due to link failures (a consequence of mobility) to congestion. The resulting overall degradation of throughput especially affects connections with a large number of hops, where link failures are more likely; thus, short connections enjoy an unfair advantage. Furthermore, if the IEEE 802.11 MAC protocol is used, the problems are exacerbated due to the protocol-induced capture effect, leading to greater unfairness and a further throughput degradation. We develop a scheme, called split TCP, which separates the TCP functions of congestion control and reliable packet delivery. For any TCP connection, certain nodes along the route take up the role of being proxies for that connection. The proxies buffer packets upon receipt and administer rate control. The buffering enables dropped packets to be recovered from the most recent proxy. The rate control helps in controlling congestion on inter-proxy segments. Thus, we emulate shorter TCP connections and can thereby achieve better parallelism in the network. Simulations show that the use of proxies improves the total throughput by as much as 30% in typical scenarios and reduces unfairness significantly. In terms of an unfairness metric that we introduce, the unfairness decreases from 0.8 to 0.2 (1.0 being the maximum unfairness). We conclude that incorporating TCP proxies is beneficial in terms of improving TCP performance in ad hoc networks.

A trnL-F cpDNA sequence study of the Condamineeae-Rondeletieae-Sipaneeae complex with implications on the phylogeny of the Rubiaceae

Abstract: DNA sequences from the chloroplast trnL-F region of 154 Rubiaceae and 11 outgroup taxa were analyzed cladistically. An emphasis was placed on the tribes Rondeletieae, Sipaneeae, and Condamineeae. Sipaneeae are not close to Rondeletieae and belong in the Ixoroideae. There is no support for a widely distributed Rondeletieae in a broad sense. Instead, Rondeletieae sensu stricto form an almost entirely Antillean clade. Support was found for the separation of Arachnothryx, Rogiera, Roigella, and Suberanthus from Rondeletia. The Guettardeae as well as Gonzalagunia are found close to a complex formed by Arachnothryx, Javorkaea, and Rogiera. Condamineeae, in a strict sense, belongs in the Ixoroideae. A number of Rondeletieae genera should be transferred to Condamineeae or other parts of Ixoroideae. Support is found for an emended tribe Naucleeae, comprising several genera with spherical pseudanthia. For the first time, tribal or subfamilial affiliation based on molecular sequence data is suggested for Allenanthus, Blepharidium, Chione, Coutaportla, Dolichodelphys, Mazaea, Neobertiera, Neoblakea, Phialanthus, Phyllacanthus, Phyllomelia, Schmidtottia, and Suberanthus.

The Metabolic Response Of Plants To Oxygen Deficiency

Abstract: As plantas, em condicoes naturais ou experimentais, podem ser submetidas a disponibilidade de O2 que varia desde os teores normais (normoxia), passando pela deficiencia (hipoxia) ou ate mesmo pela ausencia (anoxia). Varios processos metabolicos sao afetados pela deficiencia de O2, porem os eventos mais estudados sao aqueles relacionados a respiracao e ao metabolismo de N. Na ausencia de um aceptor eletronico terminal na cadeia de transporte de eletrons, o ciclo do acido tricarboxilico passa a funcionar parcialmente e em ambas as direcoes. Ocorre a acidificacao do citosol e o piruvato, produto da glicolise, e transformado em lactato e etanol, que representam as principais reacoes fermentativas das plantas. A alanina e o terceiro mais importante produto do metabolismo anaerobico, sendo resultante de altas taxas de interconversao entre os aminoacidos em que as transaminases, tais como alanina aminotransferase, desempenham um papel importante. O acumulo de alanina sob anaerobiose parece ser independente da fonte de N: NO3-, NH4+ ou N2 e o seu papel precisa ser esclarecido. Da mesma forma, ainda nao esta completamente entendido como o NO3- exerce seu efeito benefico sobre a tolerância radicular a hipoxia em plantas encharcadas. Tais aspectos do metabolismo de N colocam desafios interessantes para as futuras pesquisas sobre as respostas das plantas a deficiencia de oxigenio.

Too many of a good thing? The effects of multiple motivations on stress, cost, fulfillment, and satisfaction

Abstract: Individuals engage in behaviors to satisfy motivations and can engage in the same behavior to satisfy a variety of different motivations Previous research has examined how differences in the overall amount of motivation influence outcomes but has not addressed how differences in the number of conceptually distinct motivations one has for a particular action influence outcomes In two longitudinal field studies, individuals with more than one motivation for volunteering experienced greater negative outcomes than did those who volunteered to satisfy a single motivation A laboratory study manipulated the number of motivations individuals had for engaging in a volunteer activity Individuals with two motivations reported greater negative outcomes than did those with one motivation The importance of these findings for understanding the linkages of motivation and action in self-regulated behaviors is discussed

Matrix Metalloproteinase-2 And -9 Activities Correlate With The Disease-free Survival Of Oral Squamous Cell Carcinoma Patients.

Abstract: The aim of the present study was to determine whether matrix metalloproteinase (MMP) activities are associated with the clinicopathological features of oral squamous cell carcinomas (OSCCs). Forty-four samples of primary OSCCs were microdissected, incubated in serum-free cell culture medium for 16 h, and the activity of secreted MMPs analyzed by gelatin zymography and densitometry. Two major enzymes with gelatinolytic activity were produced by all tumor samples and characterized as MMP-2 and -9 by their molecular weight, immunoprecipitation using monoclonal antibodies, and specific inhibition by 1,10-phenanthroline or EDTA. Patients with tumors showing elevated activity of MMP-2 and -9 had shorter disease-free survival after treatment than patients with tumors exhibiting low MMP activities. These results suggest that the zymographic measurement of the MMP-2 and -9 activities in OSCC specimens may be useful to predict the disease-free survival period of patients affected by these tumors.

A feature re-weighting approach for relevance feedback in image retrieval

Abstract: Users of image databases often prefer to retrieve relevant images by categories. Unfortunately, images are usually indexed by low-level features like color, texture and shape, which often fail to capture high-level concepts well. To address this issue, relevance feedback has been extensively used to associate low-level image features with highlevel concepts. Among all existing relevance feedback approaches, query movement and feature re-weighting have been proven to be suitable for large-scaled image databases with high dimensional image features. We present a feature re-weighting approach using relevant images as well as irrelevant ones in the relevance feedback. As far as feature re-weighting approaches are concerned, one of their common drawbacks is that the feature re-weighting process is prone to be trapped by suboptimal states. To overcome this problem, we introduce a disturbing factor, which is based on the Fisher criterion, to push the feature weights out of sub-optimum. Experimental results on a large-scaled image database with 31,438 COREL images demonstrate the effectiveness of the presented method.

Foreign Direct Investment And Technological Capabilities In Brazilian Industry

Abstract: The purpose of this paper is to make a contribution to a further understanding of the implications of the growing presence of foreign affiliates for deepening technological capabilities (TCs) in Brazilian industry. It proposes a TC classification that emphasises the distinction between the use and generation of knowledge and presents a methodology for composing TC proxies by means of an innovation survey database. The findings suggest that both foreign and domestics firms have accumulated substantial capabilities for using existing technology, but only shallow capabilities for locally generating technologies. However, foreign affiliates score higher than their local counterparts in more complex capabilities, confirming their centrality in the Brazilian learning system. This gives ground for urging the elaboration of strategic foreign direct investment (FDI) policies that strengthen and deepen local TCs.

Journal diffusion factors: A new approach to measuring research influence

Abstract: This paper introduces a new bibliometric tool, the journal diffusion factor. An argument is presented that the bibliometric indicators commonly used to measure the quality of research (journal impact factor, immediacy index and cited half‐life) offer little insight into the transdisciplinary reception (thus the wider influence) of journals. The journal diffusion factor describes a neglected dynamic of citation reception and is intended as a complementary partial indicator for research evaluation purposes, to be read alongside existing well‐established indicators.

Towards an understanding of human impact upon the hydrology of Lake Naivasha, Kenya

Abstract: The water balance of Lake Naivasha, has been calculated from a model based upon the long-term meteorological data of rainfall, evaporation and river inflows. The lake is Kenya's second Ramsar site because of its international importance as a wetland, but supplies drinking water to Nakuru and irrigation water to the nationally important industries of horticulture and power generation. Groundwater flows into and out of the lake are estimated from the model's success in predicting water level fluctuations over the same period. The most accurate predictions of lake level were derived from the data sets of river discharges known to be from the most-reliable time period and gauging stations. The model estimated a current annual abstraction rate of 60 × 106 m3 ann−1, a figure perhaps six-times higher than that calculated as a `safe' yield in the 1980s. There is an urgent need to accurately measure all abstractions and provide consistent, reliable, hydrological and meteorological data from the catchment, so that a `safe' yield may be agreed upon by all stakeholders and sustainable use of the lake waters achieved.

The systematics of Holarctic bosminids and a revision that reconciles molecular and morphological evolution

Abstract: Bosminids are ubiquitous and abundant crustacean herbivores in freshwater ecosystems. They are among the best preserved zooplankters in limnological sediments, making them ideal paleolimnological indicators of ecosystem change. Moreover, their egg banks make possible the study of paleogenetics and resurrection ecology. A major limitation to these comparative disciplines is that the relatedness and identities of compared bosminid specimens or subfossils is often uncertain. We aimed to remedy this by developing the first robust molecular phylogeny of the group and inferring patterns of morphological evolution. We used sequence alignments of five nuclear rDNA genes (partial 18S rDNA, internal transcribed spacer 1 [ITS-1], 5.8S, ITS-2, and partial 28S rDNA) and one mitochondrial gene (partial 16S rDNA) from representative Holarctic species from all of the proposed subgenera and genera. No evidence of within-individual sequence variation in the gene regions analyzed was found for the genus Bosmina and the genus Eubosmina. Our nuclear and mitochondrial genetic results revealed a robust phylogeny and were congruent with morphological changes. Competing morphological schemes of bosminid systematics were reconciled by reassigning several species to different subgenera, resurrecting the genus Eubosmina, erecting a new subgenus, and revising the character coding systems that created paraphyletic groups. The results provide an evolutionary framework with diagnostic genetic and morphologic characters for studies of bosminid paleolimnology and paleogenetics.

Feeding of the exotic Louisiana red swamp crayfish, Procambarus clarkii (Crustacea, Decapoda), in an African tropical lake: Lake Naivasha, Kenya

Abstract: The Louisiana red swamp crayfish, Procambarus clarkii, has had a major impact on aquatic ecosystems in Europe and America where it has been introduced for human consumption. In Lake Naivasha, where it was introduced in 1970, it is suspected of causing the complete disappearance of native floating-leaved and submerged plants by 1982 and again by 1996; recovery of submerged plants occurred in between, concurrent with a decline in P. clarkii. Examination of the feeding of P. clarkii by microscopic analysis of gut contents collected from the lake confirmed information from both its native and exotic ranges; that it is an omnivore with green plants and insects the predominant items recognised. Feeding experiments confirmed this omnivory, with a preference from herbivory over carnivory. They further showed the importance of native plants as opposed to exotic water hyacinth Eichhornia crassipes. It is concluded that P. clarkii could well have accounted for the observed elimination of native plant species in Lake Naivasha; the cyclical nature of populations of submerged plant species and of P. clarkii in inverse proportion to each other lead us to hypothesise that P. clarkii is a `keystone' species in the lake ecosystem.

Catalan Numbers, The Hankel Transform, And Fibonacci Numbers

Abstract: We prove that the Hankel transformation of a sequence whose elements are the sums of two adjacent Catalan numbers is a subsequence of the Fibonacci numbers. Thisisdonebyflndingtheexplicitformforthecoe‐cientsinthethree-termrecurrence relation that the corresponding orthogonal polynomials satisfy.

Partner telomeres during anaphase in crane-fly spermatocytes are connected by an elastic tether that exerts a backward force and resists poleward motion

Abstract: As chromosomes move polewards during anaphase in crane-fly spermatocytes, trailing arms commonly stretch backwards for a brief time, as if tethered to their partners. To test that notion, a laser microbeam was used to sever trailing arms and thereby release telomere-containing arm segments (called acentric fragments because they lack kinetochores) from segregating chromosomes. Analysis of the movement of acentric fragments after their release provided clear evidence that previously conjoined partners were indeed tethered at their telomeres and that tethers exerted backward forces that were sufficient to move the fragment across the equator and into the opposite half-spindle. To address concerns that tethers might be artifacts of in vitro cell culture, spermatocytes were fixed in situ, and stretched arms within fixed cells provided strong evidence for tethers in vivo. The substantial resistance that tethers impose on the poleward movement of chromosomes must normally be over-ridden by the poleward 'pulling' forces exerted at kinetochores. In spermatocytes, poleward forces are supplied primarily by the 'traction fibers' that are firmly attached to kinetochores through end-on attachments to the plus ends of kinetochore microtubules.

Plasma cardiothrophin-1 following acute myocardial infarction: Relationship with left ventricular systolic dysfunction

Abstract: The glycoprotein 130 (gp 130) signalling pathway is important in the development of heart failure. Cardiotrophin-1 (CT-1), a cytokine acting via the gp 130 pathway, is involved in the process of ventricular remodelling following acute myocardial infarction (AMI) in animals. The aims of the present study were to examine the profile of plasma CT-1 following AMI in humans, and its relationship with echocardiographic parameters of left ventricular (LV) systolic function. Serial measurements of plasma CT-1 levels were made in 60 patients at 14-48 h, 49-72 h, 73-120 h and 121-192 h following AMI and at a later clinic visit. LV function was assessed using a LV wall motion index (WMI) score on admission (WMI-1) and at the clinic visit (WMI-2). Compared with values in control subjects (29.5+/-3.6 fmol/ml), the plasma CT-1 concentration was elevated in AMI patients at 14-48 h (108.1+/-15.1 fmol/ml), 49-72 h (105.2+/-19.7 fmol/ml), 73-120 h (91.2+/-14.9 fmol/ml) and 121-192 h (118.8+/-22.6 fmol/ml), and at the clinic visit (174.9+/-30.9 fmol/ml) (P<0.0001). Levels were higher following anterior compared with inferior AMI. For patients with anterior AMI, CT-1 levels were higher at the clinic visit than at earlier times. WMI-1 correlated with CT-1 at all times prior to hospital discharge (P<0.05). On best subsets analysis, the strongest correlate with WMI-1 was CT-1 level at 49-72 h (R(2)=20%, P<0.05). In conclusion, plasma levels of CT-1 are elevated soon after AMI in humans and rise further in the subsequent weeks in patients after anterior infarction. CT-1 measured soon after AMI is indicative of LV dysfunction, and this cytokine may have a role in the development of ventricular remodelling and heart failure after AMI.

Chemical solution deposition of lanthanum zirconate buffer layers on biaxially textured Ni-1.7% Fe-3% W alloy substrates for coated-conductor fabrication

Abstract: Sol-gel processing of La2Zr2O7 (LZO) buffer layers on biaxially textured Ni-1.7% Fe-3% W alloy substrates using a continuous reel-to-reel dip-coating unit has been studied. The epitaxial LZO films obtained have a strong cube texture and uniform microstructure. The effects of increasing the annealing speed on the texture, microstructure, and carbon content retained in the film were studied. On top of the LZO films, epitaxial layers of yttria-stabilized zirconia and Ceria (CeO2) were deposited using rf sputtering, and YBa2Cu3Ox (YBCO) films were then deposited using pulsed laser deposition. Critical current densities (Jc) of 1.9 MA/cm2 at 77 K and self-field and 0.34 MA/cm2at 77 K and 0.5 T have been obtained on these films. These values are comparable to those obtained on YBCO films deposited on all-vacuum deposited buffer layers and the highest ever obtained using solution seed layers.

Further characterization of the interaction between the cytoskeletal proteins talin and vinculin

Abstract: The cytoskeletal protein talin, which is thought to couple integrins to F-actin, contains three binding sites (VBS1-VBS3) for vinculin, a protein implicated in the negative regulation of cell motility and whose activity is modulated by an intramolecular interaction between the vinculin head (Vh) and vinculin tail (Vt) domains. In the present study we show that recombinant talin polypeptides containing the three VBSs (VBS1, residues 498-636; VBS2, residues 727-965; and VBS3, residues 1943-2157) each bind tightly to the same or overlapping sites within vinculin(1-258). A short synthetic talin VBS3 peptide (residues 1944-1969) was sufficient to inhibit binding of a (125)I-labelled talin VBS3 polypeptide to vinculin(1-258), and NMR spectroscopy confirmed that this peptide forms a 1:1 complex in slow exchange with vinculin(1-258). Binding of the (125)I-labelled VBS3 polypeptide was markedly temperature dependent, but was not inhibited by 1 M salt or 10% (v/v) 2-methyl-2-propanol. Attempts to further define the talin-binding site within vinculin(1-258) using a gel-blot assay were unsuccessful, but near maximal talin-binding activity was retained by a construct spanning vinculin residues 1-131 in a yeast two-hybrid assay. Interestingly, the talin VBS3 polypeptide was a potent inhibitor of the Vh-Vt interaction, and the VBS3 synthetic peptide was able to expose the actin-binding site in intact vinculin, which is otherwise masked by the Vh-Vt interaction. The results suggest that under certain conditions, talin may be an effective activator of vinculin.

Efficient global optimization using hybrid genetic algorithms

Abstract: The optimization of many realistic large-scale engineering systems can be computationally expensive. The evaluation of a single design configuration can take minutes or hours, and although computing power is steadily increasing, the complexity of the analysis codes continues to keep pace. In this paper a novel hybrid optimization method is introduced to efficiently find the global optimal of complex, highly multimodal systems. The motivation lies in the fact that to optimize many realistic engineering systems often requires numerous computationally expensive analyses to be performed. Heuristic optimization algorithms such as Simulated Annealing or Genetic Algorithms often can locate near optimal solutions but can require many function evaluations. Local search algorithms, including both gradient and non-gradient based methods, are quite efficient at finding the optimal within convex areas of the design space but often fail to find the global optimal in multimodal design spaces. The hybrid optimization approach presented in this work switches between global and local search methods based on the local topography of the design space. The global and local optimizers work in concert to efficiently locate quality design points better that either could alone. To demonstrate the usefulness of the approach presented in this paper, two case studies of differing complexity are considered.

Multidimensional Design Visualization in Multiobjective Optimization

Abstract: Some of the first attempts at using visualization methods to aid decisions in design and optimization are found in [1]. More recent advances in computer visualization and Virtual Reality (VR) [2-4] are allowing designers and scientists to interact and manipulate vast amounts of data. Until these innovations, computers were solely relied on to interpret results and compute answers based on programs written. It is now possible to interact with these large datasets even while they are being used in running analyses [5-11]. Users have the ability to compress large amounts of data into a visual format, to investigate trends and relationships that could not be seen otherwise, and then make informed decisions regarding a product or process design. As our ability to generate more and more data for increasingly large engineering models improves, the need for means of managing that data becomes greater. Information management from a decisionmaking perspective involves being able to capture and then represent significant information to a designer so that he or she can make effective and efficient decisions. However, most visualization techniques used in engineering, such as graphs and charts, are limited to two-dimensional representations and at most three-dimensional representations. In this paper, we present a technique used to capture and represent engineering information in a multidimensional context. In this paper, we present an overview of the technique and provide details regarding two specialized functions for use in multidimensional and multiobjective optimization. This method is part of an effort to develop a comprehensive visualization-based optimization tool for multi-objective and robust design problems. Commercial companies such as Raytheon [12] and Boeing [3], among others, have attempted to improve their own design processes by taking advantage of Virtual Reality and Scientific Visualization. Virtual Reality and Scientific Visualization offer methods and concepts to produce graphical representations (pictures, graphs, etc.) of complex data. The enormous computing power readily available today has made these technologies more and more useful in recent years. Tools and techniques based on these technologies are being developed that can further improve the efficiency and accuracy of the solutions to these complex design problems. However, there is still a need for process improvement and multidimensional data representation, as well as for better incorporation of heuristics and design knowledge. One approach is through the implementation of Computational Steering concepts. Computational Steering [7-10] is the implementation of Virtual Reality and Scientific Visualization into a process or analysis, so as to give a researcher or practitioner the ability to view how a solution Background Engineers are increasingly able to generate more and more data for large system models, and as a result, the need for methods for managing and visualizing that data becomes greater. From a design perspective, large-scale analysis can result in a huge number of potential design configurations existing in complicated multi-dimensional spaces. This information could be presented to a designer as page after page of printed data. However, it is very difficult to make sense of large data structures in print form. 1 American Institute of Aeronautics and Astronautics The second subcategory contains non-ABV methods that do not require a topographical representation of the problem, such as tabular data, 2D plots, parallel coordinate based, and physical programming based methods. The method presented here, Cloud Visualization (CVis), is a category 2b visualization method meaning that it is a Non-ABV method that does not begin with a topographical view of the design space. Readers interested in more detailed discussion of the advantages and disadvantages of ABV and non-ABV are directed to [11] for more information. procedure is progressing. The researcher has the ability to alter parameters while the analysis is running to interactively \"steer\" it to a solution. This ability to interact visually with design and optimization processes has the potential to benefit decision making greatly, as estimations indicate that approximately 70% of a human’s attention is dedicated to visual input [13]. To this end, visualization can and should be considered a solution tool rather than simply a way to present results [14]. Because of the significant dependence that engineers have on visual cues and information representation, it seems sensible to provide visually enhanced design steering and optimization methodologies. Easily interpreted visual cues such as color, shape, relative size, etc. can be used effectively to convey trends or large amounts of perhaps imprecise information quickly. They can also be used to add dimension to data beyond the three spatial dimensions. In this paper, some of these cues are integrated into a visualization framework, which acts as the designer interface while single or multiobjective optimization techniques operate at a lower, processing level. This framework not only provides insight into the nature of the problem and the optimization algorithm, but also helps prevent wasted analysis and supplies the designer with an opportunity to interact with the analysis. The next section begins a description of the features of CVis most relevant to this paper. Cloud Visualization Description Cloud Visualization is a means by which a designer can view all previously generated design information in both the design and the performance spaces simultaneously. Its implementation resembles that of the Visiview method developed by Bangay [15] with some significant differences. Design spaces are defined by the design variables of the problem while performance spaces are defined by the performance objectives. All spaces are displayed in separate windows that can be linked (as described later). The following sections describe some of the features of CVis. Real-time visualization methods can be classified into two general categories: Artifact-Based Visualization (ABV) schemes and Non-ArtifactBased Visualization (Non-ABV) schemes [11]. Artifact-based schemes are those that are typically imposed on a physical object with a prescribed geometry, such as representing the stress in a beam by color contours imposed on the beams geometry. Non-Artifact-based schemes are those that are not constrained by a physical geometry such as visualization of process optimizations. General Information Design information is presented as a cloud of design points plotted along three or less axes that represent either design variables or objective functions. The color of the cloud may vary throughout its volume to reflect the properties of each area. The data represented may be single or multi-objective but this paper will focus only on multi-objective problems. If design variables are displayed, then the design space is bounded by a transparent box, indicating side constraints of the problem. If objective functions are displayed, then the performance space will not include a bounding box. Regardless of which space is plotted, CVis starts with blank three dimensional spaces until the user specifies the number of variables or objectives in the problem. Non-ABV can also be further divided into two subcategories [11]. The first includes those methods that are based on a topographical view of the design space whereby a fit is made to the performance objectives based on the results of many a priori system evaluations. The results are usually viewed as contour plots. As pointed out in [11], approaches of this type require that system evaluations be performed before the optimization begins in order to create the contours, they do not accommodate multidimensional data very well, and the representation may not be meaningful due to inadequacy of the system model and/or approximations used to generate the contour plots. Figure 1 shows a screen capture of the CVis environment with some arbitrary data being displayed. The design space is on the left (including the side constraint box). The two dimensional performance space is on the right (Z axis is not used). 2 American Institute of Aeronautics and Astronautics Figure 1 – The CVis Environment Cloud Visualization is a module that can be used by any of the optimizers in our in-house optimization toolbox. It can be used to monitor an optimization continuously, periodically, or upon completion. The above data shows design information developed during the run of a multi-objective genetic algorithm (MOGA). Coding CVis is coded entirely using OpenGL and ANSI C++. It is therefore portable to a number of platforms. All of the runs in this paper are performed on a PC with a 1.3 GHz Pentium IV processor. Interaction The spaces can be freely translated, rotated, and scaled to aid in exploration. The window colors (axes, background, bounding box) can be freely changed to improve clarity. For a close up look of a particular region of a space, the user can use the zoom box to zoom in on a windowed. Further discussion of the interactive capabilities is presented in the following sections. Point Selection To further aid in discovering useful information about the problem, points may be selected in the spaces (groups of or individual points). The selected points will then be displayed by themselves. More information about point selection will be presented in later sections. Use of Color The use of color in visualization techniques can be very effective, but it can also be overwhelming, decreasing the effectiveness of the presentation and the value of the information [16]. Too many colors can only confuse users and the simple use of gray scales can often be more effective than elaborate color schemes [17]. To this end, the color scheme used in this paper shows all points colored according to a blocked color scheme whereby all feasible, non-optim

Multiattribute decision making using hypothetical equivalents

Abstract: In this paper, the problem of selecting from among a set of alternatives using multiple, potentially conflicting criteria is discussed. A number of approaches are commonly used to make these types of decisions in engineering design, including pair-wise comparisons, ranking methods, rating methods, weighted sum approaches, and strength of preferences methods. In this paper, we first demonstrate the theoretical and practical flaws with a number of these commonly employed methods. We then present a method based on the concept of hypothetical equivalents and expand the method to include hypothetical inequivalents. We demonstrate the strengths and weaknesses of the various decision making approaches using an aircraft selection problem. The design of a research laboratory is used to demonstrate the method of hypothetical equivalents further.Copyright © 2002 by ASME

A paired study comparing the efficacy of renal preservation by normothermic autologous blood perfusion and hypothermic pulsatile perfusion.

Abstract: THE REDUCTION in metabolic rate effected by hypothermia constitutes the central tenet of traditional organ preservation. The antithesis of this approach is to provide for metabolic demand during normothermic preservation. This latter strategy has two potential benefits. First, if metabolic requirements are met during preservation, then longer preservation with better posttransplant function may be achieved than for an organ suffering prolonged cold ischemia. Second, normothermic perfusion may allow ex vivo organ function to be restored and therefore assessed prior to transplantation. This may provide a basis for viability assessment, thus reducing the risks of primary nonfunction of allografts. POPS (pulsatile organ perfusion system) (Transmedics, Boston, Mass, USA) is a new warm perfusion system for organs, using blood as the principle component of the perfusate. The aim of this study was to compare the efficacy of preservation of porcine kidneys by normothermic autologous blood perfusion and hypothermic machine perfusion (RM3 system, Waters, Mass, USA.)

Characters of U(gl(n))-reflection equation algebra

Abstract: We list characters (one-dimensional representations) of the reflection equation algebra associated with the fundamental vector representation of the Drinfeld–Jimbo quantum group \(\mathcal{U}\)q(gl(n)).

12-Te-5 pertelluranes from 1,6-dioxa-6a-tellurapentalenes. Synthesis, structure, and reactivity

Abstract: Etude de l'addition oxydante du brome et du chlore sur le diphenyl-2,5 dioxa-1,6tellura-6a Te IV pentalene: obtention d'ylures de pertelluranes qui sont des oxydants doux pour thiols, selenols et tellurures et qui peuvent etre reduits par ces composes ou l'hydrazine en dioxatellura-Te IV pentalenes

Robust design through the use of a hybrid genetic algorithm

Abstract: In this paper we present a hybrid optimization approach to perform robust design. The motivation for this work is the fact that many realistic engineering systems are mutimodal in nature with multiple local optima, and moreover may have one or more uncertain design parameters. The approach that is presented utilizes both local and global optimization algorithms to find good design points more efficiently than either could alone. The mean and variance of the objective function at a design point is calculated using Monte Carlo simulation and is used to drive the optimization process. To demonstrate the usefulness of this approach a case study is considered involving the design of a beam with dimensional uncertainty.

Visualization of multidimensional design and optimization data using cloud visualization

Abstract: As our ability to generate more and more data for increasingly large engineering models improves, the need for methods for managing that data becomes greater. Information management from a decision-making perspective involves being able to capture and represent significant information to a designer so that they can make effective and efficient decisions. However, most visualization techniques used in engineering, such as graphs and charts, are limited to twodimensional representations and at most three-dimensional representations. In this paper, we present a new visualization technique to capture and represent engineering information in a multidimensional context. The new technique, Cloud Visualization, is based upon representing sets of points as clouds in both the design and performance spaces. The technique is applicable to both single and multiobjective optimization problems and the relevant issues with each type of problem are discussed. A multiobjective case study is presented to demonstrate the application and usefulness of the Cloud Visualization techniques. 1 Motivation