bluuebunny/crossref_metadata_2025 huggingface dataset:
Some generalizations of Bailey's birth death and migration model
Authors: Davis A. W.
Published: November 2006

Some results for a general Markov branching-diffusion process are presented, and applied to a model recently considered by Bailey. Moments of the limiting distributions of certain natural measures of the spatial location and dispersion of the population are shown to be expressible in terms of the Lauricella FD-type hypergeometric functions, when the population multiplies according to the simple birth and death process with λ > μ.
Multiple channel queues in heavy traffic. I
Authors: Iglehart Donald L. , Whitt Ward
Published: November 2006

The queueing systems considered in this paper consist ofrindependent arrival channels andsindependent service channels, where as usual the arrival and service channels are independent. Arriving customers form a single queue and are served in the order of their arrival without defections. We shall treat two distinct modes of operation for the service channels. In the standard system a waiting customer is assigned to the first available service channel and the servers (servers ≡ service channels) are shut off when they are idle. Thus the classicalGI/G/ssystem is a special case of our standard system. In the modified system a waiting customer is assigned to the service channel that can complete his service first and the servers are not shut off when they are idle. While the modified system is of some interest in its own right, we introduce it primarily as an analytical tool. Letλidenote the arrival rate (reciprocal of the mean interarrival time) in theith arrival channel andμjthe service rate (reciprocal of the mean service time) in thejth service channel. Thenis the total arrival rate to the system andis the maximum service rate of the system. As a measure of congestion we define the traffic intensityρ=λ/μ.
Anatomy of learning: Instructional design principles for the anatomical sciences
Authors: Terrell Mark
Published: November 2006

Teaching anatomy is becoming increasingly challenging due to the progressive evolution of university teaching missions, student populations, medical and undergraduate curricula, coupled with a paucity of empirically tested evidence‐based instructional practices in the anatomical and medical education literature. As a mechanism to confront these pedagogical challenges, recent advances in educational psychology are analyzed for developing a framework to guide educational reform efforts. Extensive research in educational psychology over the last 100 years has resulted in four major theories on human learning that have facilitated a paradigm shift from teacher‐centered to learner‐centered classrooms and are described here in temporal order of development: behavioral theory, information processing theory, metacognitive theory, and social constructivist theory. Each theory is analyzed in detail and is used to construct instructional design principles for enhancing anatomical education research and practice. An example of a cognitively based learning environment for an undergraduate anatomy course is presented. Preliminary results suggest that intentionally drawing on different theories of learning when making instructional decisions gave students the learning support they needed to be successful and nearly doubled the course's student retention rate over a 3‐year period. Anat Rec (Part B: New Anat) 289B:252–260, 2006. © 2006 Wiley‐Liss, Inc.
Anatomy of reflux: A growing health problem affecting structures of the head and neck
Authors: Lipan Michael J. , Reidenberg Joy S. , Laitman Jeffrey T.
Published: November 2006

Gastroesophageal reflux disease (GERD) and laryngopharyngeal reflux (LPR) are sibling diseases that are a modern‐day plague. Millions of Americans suffer from their sequelae, ranging from subtle annoyances to life‐threatening illnesses such as asthma, sleep apnea, and cancer. Indeed, the recognized prevalence of GERD alone has increased threefold throughout the 1990s. Knowledge of the precise etiologies for GERD and LPR is becoming essential for proper treatment. This review focuses on the anatomical, physiological, neurobiological, and cellular aspects of these diseases. By definition, gastroesophageal reflux (GER) is the passage of gastric contents into the esophagus; when excessive and damaging to the esophageal mucosa, GERD results. Reflux that advances to the laryngopharynx and, subsequently, to other regions of the head and neck such as the larynx, oral cavity, nasopharynx, nasal cavity, paranasal sinuses, and even middle ear results in LPR. While GERD has long been identified as a source of esophageal disease, LPR has only recently been implicated in causing head and neck problems. Recent research has identified four anatomical/physiological “barriers” that serve as guardians to prevent the cranial incursion of reflux: the gastroesophageal junction, esophageal motor function and acid clearance, the upper esophageal sphincter, and pharyngeal and laryngeal mucosal resistance. Sequential failure of all four barriers is necessary to produce LPR. While it has become apparent that GER must precede both GERD and LPR, the head and neck distribution of the latter clearly separates these diseases as distinct entities warranting specialized focus and treatment. Anat Rec (Part B: New Anat) 289B:261–270, 2006. © 2006 Wiley‐Liss, Inc.
Reflections on eponyms in neuroscience terminology
Authors: Duque‐Parra Jorge Eduardo , Llano‐Idárraga J. Oskar , Duque‐Parra Carlos Alberto
Published: November 2006

Eponyms have played a very significant linguistic role in technical and scientific terminology. They are an important feature of language that have contributed for a long time to engraving in history the names of those researchers who have devoted their lives to scientific discovery. In the field of medical terminology, they are an asset, although their semantic effectiveness has constituted a long‐standing debate. We will analyze how language contributes to the advance of science and technology and the current position of eponyms in the health sciences. Eponymy in neuroscience has been used for a long time as a way to identify and recognize scientific issues, such as diseases, syndromes, methods, processes, substances, organs, and parts of organs as a way to honor those who, in a certain way, contributed to the progress of science. However, sometimes those honors do not correspond to the real contributors, thus receiving a nondeserved acknowledgment. Another problem with eponymic references is the lack of information about the matter in hand, because eponyms do not provide any clear information leading to the identification of the situation under study, as they are not reasonably descriptive. The aim of this article is to encourage the use of descriptive terms instead of eponyms and to establish a system of scientific nomenclature to consolidate the use of the language as a means of conveying scientific information among experts. Anat Rec (Part B: New Anat) 289B:219–224, 2006. © 2006 Wiley‐Liss, Inc.
Dynamic analysis of GS‐NS0 cells producing a recombinant monoclonal antibody during fed‐batch culture
Authors: Stansfield Scott H. , Allen Emma E. , Dinnis Diane M. , Racher Andrew J. , Birch John R. , James David C.
Published: November 2006

In this study we have analyzed the dynamic covariation of the mammalian cell proteome with respect to functional phenotype during fed‐batch culture of NS0 murine myeloma cells producing a recombinant IgG4 monoclonal antibody. GS‐NS0 cells were cultured in duplicate 10 L bioreactors (36.5°C, 15% DOT, pH 7.0) for 335 h and supplemented with a continuous feed stream after 120 h. Cell‐specific growth rate declined continuously after 72 h of culture. Cell‐specific recombinant monoclonal antibody production rate (qP) varied sixfold through culture. Whilst qP correlated with relative recombinant heavy chain mRNA abundance up to 216 h, qP subsequently declined, independent of recombinant heavy chain or light chain mRNA abundance. GS‐NS0 cultures were sampled at 48 h intervals between 24 and 264 h of culture for proteomic analyses. Total protein abundance and nascent polypeptide synthesis was determined by 2D PAGE of unlabeled proteins visualized by SYPRO® Ruby and autoradiography of 35S‐labeled polypeptides, respectively. Covariation of nascent polypeptide synthesis and abundance with biomass‐specific cell growth, glucose and glutamate consumption, lactate and Mab production rates were then examined using two partial least squares regression models. Most changes in polypeptide synthesis or abundance for proteins previously identified by mass spectrometry were positively correlated with biomass‐specific growth rate. We conclude that the substantial transitions in cell physiology and qP that occur during culture utilize a relatively constant complement of the most abundant host cell machines that vary primarily with respect to induced changes in cell growth rate. Biotechnol. Bioeng. 2007;97: 410–424. © 2006 Wiley Periodicals, Inc.
Measurement of biodegradability parameters for single unsubstituted and methylated polycyclic aromatic hydrocarbons in liquid bacterial suspensions
Authors: Dimitriou‐Christidis Petros , Autenrieth Robin L. , McDonald Thomas J. , Desai Anuradha M.
Published: November 2006

Substrate depletion experiments were conducted to characterize aerobic biodegradation of 20 single polycyclic aromatic hydrocarbons (PAHs) by induced Sphingomonas paucimobilis strain EPA505 in liquid suspensions. PAHs consisted of low molecular weight, unsubstituted, and methyl‐substituted homologs. A material balance equation containing the Andrews kinetic model, an extension of the Monod model accounting for substrate inhibition, was numerically fitted to batch depletion data to estimate extant kinetic parameters including the maximal specific uptake rates, qmax, the affinity coefficients, KS, and the substrate inhibition coefficients, KI. Strain EPA505 degraded all PAHs tested. Applied kinetic models adequately simulated experimental data. A cell proliferation assay involving reduction of the tetrazolium dye WST‐1 was used to evaluate the ability of strain EPA505 to utilize individual PAHs as sole energy and carbon sources. Of the 22 PAHs tested, 9 supported bacterial growth. Evaluation of the biokinetic data showed that qmax correlated highly with transmembrane flux as theoretically estimated by a diffusion model, pointing to transmembrane transport as a potential rate‐determining process. The biodegradability data generated in this study is essential for the development of quantitative structure‐activity relationships (QSARs) for biodegradability and for modeling biodegradation of simple PAH mixtures. Biotechnol. Bioeng. 2007;97: 922–932. © 2006 Wiley Periodicals, Inc.
A simplified bioprocess for human alpha‐fetoprotein production from inclusion bodies
Authors: Leong Susanna S.J. , Middelberg Anton P.J.
Published: November 2006

A simple and effective Escherichia coli (E. coli) bioprocess is demonstrated for the preparation of recombinant human alpha‐fetoprotein (rhAFP), a pharmaceutically promising protein that has important immunomodulatory functions. The new rhAFP process employs only unit operations that are easy to scale and validate, and reduces the complexity embedded in existing inclusion body processing methods. A key requirement in the establishment of this process was the attainment of high purity rhAFP prior to protein refolding because (i) rhAFP binds easily to hydrophobic contaminants once refolded, and (ii) rhAFP aggregates during renaturation, in a contaminant‐ dependent way. In this work, direct protein extraction from cell suspension was coupled with a DNA precipitation‐centrifugation step prior to purification using two simple chromatographic steps. Refolding was conducted using a single‐step, redox‐optimized dilution refolding protocol, with refolding success determined by reversed phase HPLC analysis, ELISA, and circular dichroism spectroscopy. Quantitation of DNA and protein contaminant loads after each unit operation showed that contaminant levels were reduced to levels comparable to traditional flowsheets. Protein microchemical modification due to carbamylation in this urea‐based process was identified and minimized, yielding a final refolded and purified product that was significantly purified from carbamylated variants. Importantly, this work conclusively demonstrates, for the first time, that a chemical extraction process can substitute the more complex traditional inclusion body processing flowsheet, without compromising product purity and yield. This highly intensified and simplified process is expected to be of general utility for the preparation of other therapeutic candidates expressed as inclusion bodies. Biotechnol. Bioeng. 2007;97:99–117. © 2006 Wiley Periodicals, Inc.
Regulation and characterization of the polarity of cells embedded in a reconstructed basement matrix using a three‐dimensional micro‐culture system
Authors: Torisawa Yu‐suke , Nashimoto Yuji , Yasukawa Tomoyuki , Shiku Hitoshi , Matsue Tomokazu
Published: November 2006

Three cell lines, that is, the human breast cancer cell line (MCF‐7) and the human mammary epithelial cell line (S‐1) and its malignant form (T4‐2) were embedded in a reconstituted basement membrane (Matrigel) that had 20‐nL pyramid‐shaped silicon microstructures. The proliferative behavior of the MCF‐7 cells was dependent on the surrounding conditions (2‐D, collagen gel, or Matrigel), whereas the respiratory activity of a single cell (Fc) was almost identical under different culture conditions. The Fc value changed with cellular polarity. The Fc value for the S‐1 cells was observed to decrease slightly, whereas that of the T4‐2 cells increased 2 days after cultivation in the microstructures within the Matrigel. However, when the T4‐2 cells were cultured in the presence of tyrphostin AG 1478 (T4‐2 tyr) to inhibit epidermal growth factor (EGF) signaling, the Fc value decreased slightly and remained almost constant for an additional 1 week; this was similar to the behavior of the S‐1 cells. Further, fluorescence images showed that the T4‐2 tyr cells formed polar structures that were similar to those formed by the S‐1 cells whereas the T4‐2 cells did not form such structures. These results indicate that cellular polarity can be assessed by measuring cellular respiratory activity. Biotechnol. Bioeng. 2007;97: 615–621. © 2006 Wiley Periodicals, Inc.
Degradation of supercoiled plasmid DNA within a capillary device
Authors: Meacle F.J. , Zhang H. , Papantoniou I. , Ward J.M. , Titchener‐Hooker N.J. , Hoare M.
Published: November 2006

Supercoiled plasmid DNA is susceptible to fluid stress in large‐scale manufacturing processes. A capillary device was used to generate controlled shear conditions and the effects of different stresses on plasmid DNA structure were investigated. Computational fluid dynamics (CFD) analysis was employed to characterize the flow environment in the capillary device and different analytical techniques were used to quantify the DNA breakage. It was found that the degradation of plasmid DNA occurred at the entrance of the capillary and that the shear stress within the capillary did not affect the DNA structure. The degradation rate of plasmids was well correlated with the average elongational strain rate or the pressure drop at the entrance region. The conclusion may also be drawn that laminar shear stress does not play a significant role in plasmid DNA degradation. Biotechnol. Bioeng. 2007; 97: 1148–1157. © 2006 Wiley Periodicals, Inc.
Peutz–Jeghers syndrome and screening for pancreatic cancer
Authors: Latchford A , Greenhalf W , Vitone L J , Neoptolemos J P , Lancaster G A , Phillips R K S
Published: November 2006

Background

Cancer risk, including pancreatic, is high in those with Peutz–Jeghers syndrome (PJS). It has been suggested that such patients should undergo screening for pancreatic cancer.

Methods

The risk of pancreatic cancer in PJS, pancreatic screening and potential screening strategies were reviewed. Cost-effectiveness was assessed according to American Gastroenterology Association guidelines and a risk stratification model proposed by the European Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer.

Results

The risk of pancreatic cancer is increased in PJS but screening would cost over US $350 000 per life saved. Risk stratification reduces cost by $100 000 and costs fall to $50 000 per life saved if deaths from other forms of cancer are avoided.

Conclusion

Screening should be performed only on a research basis to evaluate the benefit and cost-effectiveness in high-risk groups.
Asymmetric Synthesis of 3‐Oxa‐15‐deoxy‐16‐(m‐tolyl)‐17,18,19,20‐tetranorisocarbacyclin and Its Neuroprotective Analogue 15‐Deoxy‐16‐(m‐tolyl)‐17,18,19,20‐tetranorisocarbacyclin Based on the Conjugate Addition–Azoalkene–Asymmetric Olefination Strategy
Authors: van de Sande Marc , Gais Hans‐Joachim
Published: November 2006

A fully stereocontrolled synthesis of 3‐oxa‐15‐deoxy‐16‐(m‐tolyl)‐17,18,19,20‐tetranorisocarbacyclin (3‐oxa‐15‐deoxy‐TIC, 7 b) and a formal one of 15‐deoxy‐16‐(m‐tolyl)‐17,18,19,20‐tetranorisocarbacyclin (15‐deoxy‐TIC, 7 a) are described. 15‐Deoxy‐TIC is specific for the neuronal prostacyclin receptor (IP2) and exhibits neuroprotective activities, and the new 3‐oxa‐15‐deoxy‐TIC is expected to be metabolically more stable than 15‐deoxy‐TIC. The syntheses of 7 a and 7 b are based on the convergent conjugate addition–azoalkene–asymmetric olefination strategy. Key building blocks are the readily available bicyclic azoalkene 14 and the alkenylcopper derivative 15. The stereoselective conjugate addition of 15 to 14 gave hydrazone 13, which was stereoselectively converted to the bicyclic ketone 11. The key steps for the construction of the α side chain of 7 a and 7 b and the regioselective introduction of the endocyclic Δ6,6a double bond are: 1) a highly selective asymmetric olefination of ketone 11 with the chiral Horner–Wadsworth–Emmons reagent 28 and 2) a regioselective deconjugation of the α,β‐unsaturated ester (E)‐10 with the chiral lithium amide 29, which gave the β,γ‐unsaturated ester anti‐9 with high selectivity. The homoallylic alcohol 8 served at a late stage as the joint intermediate in the syntheses of 7 a and 7 b. While an etherification of 8 furnished, after hydrolysis and deprotection, 3‐oxa‐15‐deoxy‐TIC, its alkylation afforded alcohol 37, the known precursor for the synthesis of 15‐deoxy‐TIC.
Total Syntheses of Zaragozic Acids A and C by a Carbonyl Ylide Cycloaddition Strategy
Authors: Hirata Yuuki , Nakamura Seiichi , Watanabe Nobuhide , Kataoka Osamu , Kurosaki Takahiro , Anada Masahiro , Kitagaki Shinji , Shiro Motoo , Hashimoto Shunichi
Published: November 2006

A carbonyl ylide cycloaddition approach to the squalene synthase inhibitors zaragozic acids A and C is described. The carbonyl ylide precursor 8 was synthesized starting from di‐tert‐butyl D‐tartrate (47) via an eleven‐step sequence involving the regioselective reduction of the mono‐MPM (MPM = 4‐methoxybenzyl) ether 48 with LiBH4 and the diastereoselective addition of sodium tert‐butyl diazoacetate to α‐keto ester 10. The reaction of α‐diazo ester 8 with 3‐butyn‐2‐one (40) in the presence of a catalytic amount of [Rh2(OAc)4] gave the desired cycloadduct 59 as a single diastereomer. The dihydroxylation of enone 59 followed by sequential transformations permitted the construction of the fully functionalized 2,8‐dioxabicyclo[3.2.1]octane core 5. Alkene 79 derived from 5 serves as a common precursor to zaragozic acids A (1) and C (2), since the elongation of the C1 alkyl side chain can be attained by olefin cross‐metathesis, especially under the influence of Blechert's catalyst (85).
Estimation of the optimal brachytherapy utilization rate in the treatment of carcinoma of the uterine cervix
Authors: Thompson Stephen , Delaney Geoff , Gabriel Gabriel Sam , Jacob Susannah , Das Prabir , Barton Michael
Published: November 2006

BACKGROUND.

Brachytherapy (BT) is an integral part of cervical carcinoma treatment. There have been no attempts to estimate the optimal proportion of new cervical carcinoma cases that should be treated with BT, that is, the optimal rate of brachytherapy utilization (BTU).

METHODS.

Evidence‐based guidelines and primary evidence were used to construct a BTU tree for carcinoma of the uterine cervix. Searches were performed of the epidemiological literature to ascertain the proportion of patients who fulfilled criteria for BT. The robustness of the model was tested by sensitivity analyses and by peer review. A patterns of care study of BT in New South Wales for 2003 was conducted, and actual BTU for cervical carcinoma determined. The differences between optimal and actual rates of BTU were assessed.

RESULTS.

The optimal cervical carcinoma BTU was 49% (range, 42% to 50%). In New South Wales in 2003, actual BTU was only 30% of 256 cervical carcinoma patients. The major discrepancy was for FIGO stage IB‐IIA disease, where there was an underutilization of BT, estimated to be 15% actual use compared with 47% optimal use. In Surveillence, Epidemiology, and End Results (SEER) areas, there was underutilization for stage IB‐IIA (22% actual BTU versus 47% optimal BTU) and for stage IIB‐IVA (54% actual BTU versus 100% optimal BTU).

CONCLUSIONS.

BT for cervical carcinoma is underutilized in New South Wales and in SEER areas. The authors' model of optimal BTU can be used as a quality assurance tool to provide an evidence‐based benchmark against which actual patterns of practice can be measured. The model can also be used to help determine adequacy of BT resource allocation. Cancer 2006. © 2006 American Cancer Society.
Using a virtual machine to protect sensitive Grid resources
Authors: Zhao Xin , Borders Kevin , Prakash Atul
Published: November 2006

Most Grid systems rely on their operating systems (OSs) to protect their sensitive files and networks. Unfortunately, modern OSs are very complex and it is difficult to completely avoid intrusions. Once intruders compromise the OS and gain system privilege, they can easily disable or bypass the OS security protections. This paper proposes a secure virtual Grid system, SVGrid, to protect sensitive system resources. SVGrid works by isolating Grid applications in Grid virtual machines. The Grid virtual machines' filesystem and network services are moved into a dedicated monitor virtual machine. All file and network accesses are forced to go through this monitor virtual machine, where SVGrid checks request parameters and only accepts the requests that comply with security rules. Because SVGrid enforces security policy in the isolated monitor virtual machine, it can continue to protect sensitive files and networks even if a Grid virtual machine is compromised. We tested SVGrid against attacks on Grid virtual machines. SVGrid was able to prevent all of them from accessing files and networks maliciously. We also evaluated the performance of SVGrid and found that performance cost was reasonable considering the security benefits of SVGrid. Furthermore, the experimental results show that the virtual remote procedure call mechanism proposed in this paper significantly improves system performance. Copyright © 2006 John Wiley & Sons, Ltd.
Relative autonomous accounting for peer‐to‐peer Grids
Authors: Santos Robson , Andrade Alisson , Cirne Walfredo , Brasileiro Francisco , Andrade Nazareno
Published: November 2006

Here we present and evaluate relative accounting, an autonomous accounting scheme that provides accurate results even when the parties (consumer and provider) do not trust each other. Relative accounting relies on the observed relative performance amongst the parties. As such, the basic requirement to use it is that resource consumers must also be resource providers. Relative accounting is totally autonomous in the sense that it uses only local information, i.e. there is no exchange of information between the parties. This allows for the deployment of the autonomous accounting without requiring any sort of identification infrastructure, such as certificate authorities. Not requiring trust or sophisticated infrastructure makes relative accounting a perfect fit for peer‐to‐peer Grids, which aim to scale much further than traditional Grids by allowing free unidentified entry into the Grid. Our results show that relative accounting performs very close to a perfect accounting, whose implementation is infeasible in most systems, including those we target. Relative accounting was developed to work with OurGrid, a peer‐to‐peer Grid in production since December 2004, but it can also be used in other peer‐to‐peer Grids. Copyright © 2006 John Wiley & Sons, Ltd.
GRAND: toward scalability in a Grid environment
Authors: Vargas Patrícia Kayser , Dutra Inês C. , do Nascimento Vinícius D. , Santos Lucas A. S. , da Silva Luciano C. , Geyer Cláudio F. R. , Schulze Bruno
Published: November 2006

One of the challenges in Grid computing research is to provide a means to automatically submit, manage, and monitor applications whose main characteristic is to be composed of a large number of tasks. The large number of explicit tasks, generally placed on a centralized job queue, can cause several problems: (1) they can quickly exhaust the memory of the submission machine; (2) they can deteriorate the response time of the submission machine due to these demanding too many open ports to manage remote execution of each of the tasks; (3) they may cause network traffic congestion if all tasks try to transfer input and/or output files across the network at the same time; (4) they make it impossible for the user to follow execution progress without an automatic tool or interface; (5) they may depend on fault‐tolerance mechanisms implemented at application level to ensure that all tasks terminate successfully. In this work we present and validate a novel architectural model, GRAND (Grid Robust ApplicatioN Deployment), whose main objective is to deal with the submission of a large numbers of tasks. Copyright © 2006 John Wiley & Sons, Ltd.
Distributed and dynamic self‐scheduling of parallel MPI Grid applications
Authors: Nascimento Aline P. , Sena Alexandre C. , Boeres Cristina , Rebello Vinod E. F.
Published: November 2006

The execution of distributed applications on the Grid is already a reality. However, as both the number of applications grow and Grids increase in scale, the efficient utilization of the available but shared heterogeneous resources will become increasingly essential to the Grid's successful maturity. Furthermore, it is unclear whether existing Grid management systems are capable of meeting this challenge. The EasyGrid middleware is a hierarchically distributed application management system (AMS) that is embedded into MPI applications to autonomously orchestrate their execution efficiently in computational Grids. The overhead of employing a distinct AMS to make each application system aware brings at least two benefits. First, the adopted policies can be tailored to the specific needs of each application, leading to improved performance. Second, distributing the management effort among executing applications makes Grid management more scalable. This article focuses on scheduling policies of an AMS for a particular class of application, describing a low intrusion implementation of a hybrid scheduling strategy designed to elicit good performance even in dynamic environments such as Grids. Using application‐specific scheduling policies, near‐optimal runtimes highlight the advantages of self‐scheduling when executing one or more system aware applications on a Grid. Copyright © 2006 John Wiley & Sons, Ltd.
Towards increased expressiveness in service level agreements
Authors: Yarmolenko Viktor , Sakellariou Rizos
Published: November 2006

The aim of this paper is to argue for the benefits of increased expressiveness in service level agreements (SLAs). Such benefits may be obtained from the use of analytical expressions to specify a SLA's agreement terms as functions and not as variable or constant values or ranges. The main idea behind this thinking is that functions may contain variables defined in the SLA or be drawn from the known set of reference variables, such as wall‐clock time, job start time, current bandwidth of the resource, etc. Experiences and conclusions drawn are in the context of SLA‐based job management systems. We demonstrate that the use of analytical expressions in SLAs can potentially reduce the overheads associated with job renegotiation and/or reduce the number of failed agreements. Copyright © 2006 John Wiley & Sons, Ltd.
Practical experience of run‐time link reconfiguration in a multi‐transputer machine
Authors: Jones Peter , Murta Alan
Published: November 2006

The paper describes a novel message passing regime for multi‐processor machines using transputers. The development of this facillity was motivated by the disparity between the interconnect available in transputer machines and the arbitary degree of interconnect implicit in the underlying CSP model of computation. The technique presented involves the alteration of the link topology of the machine during run‐time, under the contrl of executing user code. Performance evaluation has been undertaken and the results are given. In particular, it is shown how run‐time reconfiguration leads to performance enhancement for some classes of problems.
Load balancing and Poisson equation in a graph
Authors: Boillat J. E.
Published: November 2006

We present a fully distributed dynamic load balancing algorithm for parallel MIMD architectures. The algorithm can be described as a system of identical parallel processes, each running on a processor of an arbitrary interconnected network of processors. We show that the algorithm can be interpreted as a Poisson (heath) equation in a graph. This equation is analysed using Markov chain techniques and is proved to converge in polynomial time resulting in a global load balance. We also discuss some important parallel architectures and interconnection schemes such as linear processor arrays, tori, hypercubes, etc. Finally we present two applications where the algorithm has been successfully embedded (process mapping and molecular dynamic simulation).
Product label inspection using transputers
Authors: Mirmehdi Majid
Published: November 2006

A product label inspection system implemented on a transputer network is described. Two data routing algorithms are considered, one for a general M × N array and one for a customized setup of transputers. Data transfer results for various image sizes are provided. Reliable and fast label inspection algorithms are described for rectangular, acute‐angled and oval‐shaped product labels, and their implementation on both the general and the customized networks are discussed. Simulated test results are provided to illustrate the present capability of the system for inspecting large numbers of labels per second.
Particle flow instrumentation
Authors: Mills E. , O'Neill B. C.
Published: November 2006

This paper describes the development of a real‐time particle flow meter for pneumatic conveyance systems. The subject is approached by a brief overview of the pneumatic transportation process and method of particle detection, moving to the decisions taken on the choice of host processor system, the design of the final system and the results obtained to date.

The application of this work is not confined to commercial pneumatically conveyed products, such as epoxy powder paint for electrostatic paint spraying; the measurement system itself is of interest to the CEGB for determining the efficiency of their electrostatic precipitators and exhaust‐gas‐driven turbine protection.
A transputer radar ESM data processor
Authors: Beton Richard , Kingdon James , Upstill Colin
Published: November 2006

A parallel radar ESM data processing system using occam and transputers is presented. High‐level software solutions for radar ESM to run on multiple transputer systems were investigated, to achieve high throughput cost‐effectively. The system is primarily a vehicle to support further algorithm research and to permit benchmarking; it is expandable and flexible, and can be modified to run on different numbers of processors with almost linear improvement in performance. The architecture has a hybrid pipelined structure; the topology within each stage of a concurrent processor pipeline is chosen to optimize the processing and communications for the required function. A novel technique is described for improving the load balancing of such algorithmically decomposed parallel systems.
The Radon transform on a dynamically switched transputer network
Authors: Hall G. , Terrell T. J. , Murphy L. M.
Published: November 2006

Previously reported work resulted in a transputer tree network using thirty tramputers to perform the Radon transform. The Radon transform was used to enhance linear features in noisy synthetic aperture radar images. The work presented here describes modification of the transputer network by the addition of INMOS B004 link switches, and controlling T222 transputer. The tree configuration is replaced such that link switches now dynamically switch between the image data source transputer (farmer) and the transputers which perform the calculations (workers). It is shown that this arrangement is more cost‐effective since the worker transputers are all relieved of their data‐routing role. The paper Includes a comparison of the previous tree network with the new switched network, and presents results for both techniques.
MARVIN and TINA: A multiprocessor 3‐D vision system
Authors: Rygol Michael , Pollard Stephen , Brown Chris
Published: November 2006

We describe a working multi‐transputer stereo vision system which exploits various forms of parallelism in a number of visual competences upon a specialized hardware architecture that provides distributed video datapaths to the processor array. We exploit stereo and spatial parallelism to recover 3‐D scene descriptions from passive stereo vision. To recognize and recover the positions of modelled objects, we exploit featural parallelism at both the object and sub‐object level. We also describe a real‐time object‐tracking algorithm that exploits featural parallelism in the concurrent tracking of a set of object features.

These competences have been integrated into a general‐purpose architecture and we present some performance results and descriptions of the use of this vision engine in two application domains.
Distributing gate‐level digital timing simulation over arrays of transputers
Authors: Wood Kenneth R.
Published: November 2006

Continuing advances in VLSI fabrication technology are allowing circuit designs to become more and more complex and are thereby fuelling the need for ever‐faster digital simulators. In this paper, we investigate a multi‐transputer‐based method for speeding up gate‐level digital timing simulation, the acknowledged 'workhorse' of the digital circuit design verification process. In particular, we describe a variant of the basic conservative method for distributed discrete‐event simulation and we present PARSIM, a gate‐level digital timing simulator which is based on this method and which runs on arrays of transputers. Preliminary results on small transputer arrays demonstrate good speed‐ups for bitslice partitions of circuits with regular structure, including supralinear speed‐ups for a large (1664‐gate) circuit. Although these results are encouraging, poor results for less‐than‐ideal partitions of our test circuits suggest that we require an improvement in the efficiency of deadlock resolution and/or a means of automated optimized partitioning before PARSIM can be used as a practical tool for speeding up gate‐level simulation.
Experiments with a transputer‐based parallel graph reduction machine
Authors: Rabhi Fethi A. , Manson Gordon A.
Published: November 2006

This paper is concerned with the implementation of functional languages on a parallel architecture, using graph reduction as a model of computation. Parallelism in such systems is automatically derived by the compiler but a major problem is the fine granularity, illustrated in Divide‐and‐Conquer problems at the leaves of the computational tree. The paper addresses this issue and proposes a method based on static analysis combined with run‐time tests to remove the excess in parallelism. We report experiments on a prototype machine, simulated on several connected INMOS transputers. Performance figures show the benefits in adopting the method and the difficulty of automatically deriving the optimum partitioning due to differences among the problems.
The solution of radiation engineering problems on a transputer‐based system
Authors: Khaddaj S. A. , Al‐Bahadili H. , Goddard A. J. H. , de Oliveira C. R. E. , Wood J.
Published: November 2006

Monte Carlo and finite element methods are numerical techniques used for solving complex problems in reactor physics and radiation shielding. In this paper we are concerned with the implementation of existing research‐level codes based on these two methods, written originally for serial computers, on an MIMD transputer‐based system. Results and performance of the parallelized codes are presented.
The Metrobridge—an application of transputers in transparent bridging
Authors: Robertson B. , Chopping M. , Zielinski K. , Milway D.
Published: November 2006

This paper describes the Metrobridge project—a distributed switch for connecting PC cards via a high‐speed backbone network. The paper outlines the communication and management functions that are provided, and describes the hardware and software modules that make up the system. Finally, the advantages and disadvantages of using the transputer are discussed.
Parallel computing in the 1980s—one person's view
Authors: Messina Paul C.
Published: November 2006

This paper is a survey of activities related to parallel computing that took place primarily during the 1980s. The major areas covered are hardware, software, and performance measurement and characterization. Emphasis is on identifying the major milestones of the decade and on commercial computers rather than present a comprehensive survey of the field. The material is treated from the user's point of view.
ES‐Kit: An object‐oriented distributed system
Authors: Chatterjee Arunodaya , Khanna Arjun , Hung Ying
Published: November 2006

This paper describes the design, implementation, and performance of ES‐Kit, a distributed object‐oriented system being developed by the Experimental Systems Project at the Microelectronics and Computer Technology Corporation. The operating system consists of a kernel and a set of Public Service Objects which dynamically extend the functionality of the kernel by providing several traditional operating system services when required by application objects. Applications for the ES‐Kit environment are written in GNU C++ and do not require additional language primitives for distributed execution. Initial performance results from a representative set of applications indicate that the object‐oriented paradigm provides a powerful solution to distributed programming.
Portable tools for Fortran parallel programming
Authors: Kumar Swarn P. , Philips Ivor R.
Published: November 2006

This paper presents a survey of some of the tools, techniques, and constructs for the development of portable, multitasked Fortran programs. The study mainly focuses on existing software tools that implement different approaches to achieving portability of multitasked Fortran programs for local and shared memory multiprocessor computers. However, some proposed approaches are also included. It appears that while each approach enjoys some advantages and suffers some disadvantages, at present, the development and use of portable multitasking tools is in its infancy, and thus no one system is clearly superior. Indeed, we expect that, for the foreseeable future, these and perhaps other techniques will all be actively pursued.
LAPACK: A portable linear algebra library for high‐performance computers
Authors: Demmel James
Published: November 2006

The goal of the LAPACK project is to design and implement a portable linear algebra library for etficient use on a variety of high‐performance computers. The library is based on the widely used LINPACK and EISPACK packages for solving linear equations, eigenvalue problems, and linear least‐squares problems, but extends their functionality in a number of ways. The major methodology for making the algorithms run faster is to restructure them to perform block matrix operations (e.g. matrix‐matrix multiplication) in their inner loops. These block operations may be optimized to exploit the memory hierarchy of a specific architecture. In particular, we discuss algorithms and benchmarks for the singular value decomposition.
Numerical simulation of incompressible fluid flows
Authors: Anagnostou George , Maday Yvon , Patera Anthony T. , Fischer Paul F. , Rønqist Einar M.
Published: November 2006

In this paper we discuss temporal, spatial, and architectural aspects of the numerical simulation of time‐dependent incompressible fluid flows. In particular, we consider: high‐order operator‐integration‐factor time‐splitting methods; sliding‐mesh spectral mortar‐element spatial discretizations; and data‐parallel distributed‐memory medium‐grained parallel solution techniques. Numerous flow examples are presented.
The use of the CAPE Environment in the simulation of rock fracturing
Authors: Norman M. G. , Henderson J. R. , Main I. G. , Wallace D. J.
Published: November 2006

The Cellular Automaton Programming Environment (CAPE) was developed as a programming paradigm specific tool for simulation of physical systems by cellular automata (CAs) on the Meiko Computing Surface. CAPE is structured in a way that allows application‐specific elements to be replaced whilst retaining the core of the tool.

One of the applications areas where CAPE has been used is in the initial stages of a project which is studying the complex non‐linear processes of fracture evolution and fluid flow in geological materials. We describe the programming abstraction provided by CAPE, primarily concentrating on the approach that is taken to reducing the application programmer's initial exposure to issues in parallel computing. We give a brief description of the geological processes that have been simulated, and consider the problems that are associated with this application of CAPE.
Analysis of multidimensional images on the Connection Machine system
Authors: Marcenaro Giampiero , Tistarelli Massimo
Published: November 2006

The Connection Machine (CM) has been demonstrated to be an efficient and fast computational engine for the solution of many problems related to image processing. The high‐level parallelism of the CM naturally fits to many large‐scale data intensive applications.

In this paper the implementation of parallel algorithms for the analysis of multidimensional images on the CM is presented. Different aspects in the analysis of multidimensional images are considered. In the field of artificial vision, the implementation of algorithms for the filtering of image sequences (both in space and time) and the estimation of the optical flow is described and some results in terms of accuracy and computation time are presented.

The processing of three‐dimensional images is investigated in the field of biomedical engineering. In this case the goal is the development of algorithms for the 3‐D reconstruction of human body segments and their visualization.

The parallel implementations exploit the fine grain parallelism allowed by the CM, processing each point of the data on a different processor. This mechanism is allowed by the possibility of dynamically reconfiguring the connectivity of the CM nodes and of defining a huge number of virtual processors. Moreover, as the CM processors operate on one‐bit data, it is possible to tune the number of bits for each data point to match the accuracy required by the application.
Aeroelastic applications of the Connection Machine
Authors: Sipcic Slobodan R. , Westbrook Thomas
Published: November 2006

This paper describes the implementation of a dynamical systems approach to aeroelastic analysis using the Connection Machine model 2 (CM‐2). Through numerical simulation, the regions of harmonic and chaotic behavior in the δ,Rx (velocity, in‐plane load) plane have been examined in detail. These regions are of interest in evaluation of the fatigue life of fluttering plates. The CM‐2 computer architecture allows the removal of many of the previous simplifying and limiting assumptions regarding the prediction of the stability regions maps. Owing to its high‐speed prediction capability, the CM‐2, with framebuffer, offers 'real‐time' display of the solution as it evolves during the prediction process. This feature gives insight into the fundamental way in which the solution evolves. This is essential in defining the scenarios describing roads to chaotic behavior of the dissipative dynamical systems.
Design, implementation and evaluation of a deadlock‐free routing algorithm for concurrent computers
Authors: Cannataro M. , Spezzano G. , Talia D. , Gallizzi E.
Published: November 2006

This paper describes the design, the implementation, and the performance results of a routing algorithm which provides deadlock‐free communication in a tightly coupled message‐passing concurrent computer. The algorithm is adaptive, isolated and uses the store‐and‐forward technique. It allows message communication between two processes regardless of where they are physically located on the network. The routing algorithm has many positive characteristics including provable deadlock freedom, guaranteed message arrival, and automatic local congestion reduction. It can be used as a basis for the design of high‐level communication primitives. An Occam implementation on a network of inmos Transputers is discussed. The experimental results show that the routing algorithm is effective to support process to process communication on a concurrent computer.
Parallel approaches to the solution of the assignment problem
Authors: Davis Nathaniel J. , Carpenter Barry A. , Glover Charles W. , Culioli Jean‐Christophe
Published: November 2006

This paper discusses efforts to develop parallel algorithms that can be used to solve large‐scale assignment problems typical of military battle management systems. Attempts to parallellze the classical Hungarian method are explored. Drawing on experimental data, a regresslon model is derived that relates the Hungarian method's run time to a cubic function of the number of parallel processors used in the solution. Four parallel heuristics for solving the assignment problem are developed and analysed. Two of them perform well in a parallel environment. The first, based on Vagel's approximation, can be used to identify a feasible, near‐optimal assignment. The second algorithm partitions the assignment problem into independent subproblems across the parallel array. The resulting solution, although infeasible in the strict definition of the assignment problem, is seen to be reasonably good and can be obtained very rapidly. Either of these two heuristics are of potential use in the stringent computing environment of a real‐time resource management system.
Run‐time data decomposition for parallel implementation of image processing and computer vision tasks
Authors: Choudhary Alok N. , Ponnusamy Ravi
Published: November 2006

This paper presents several static and dynamic data decomposition techniques for parallel implementation of common computer vision algorithms. These techniques use the distribution of features in the input data as a measure of load for data decomposition. Experimental results are presented by implementing algorithms from a motion estimation system using these techniques on a hypercube multiprocessor. Normally in a vision system a sequence of algorithms is employed in which output of an algorithm is input to the next algorithm in the sequence. The distribution of features computed as a by‐product of the current task is used to repartition the data for the next task in the system. This allows parallel computation of feature distribution, and therefore the overhead of estimating the load is kept small. It is observed that the communication overhead to repartition data using these run‐time decomposition techniques is very small. It is shown that significant performance improvements over uniform‐block‐oriented partitioning schemes are obtained.