bluuebunny/crossref_metadata_2025 huggingface dataset:
Management of Nuclear Plant Operation by Optimising Weld Repairs: ENPOWER Project Overview
Authors: Boucher Christian , Bouchard P. John , Brown T. Bruce , Dauda Tamba A. , Hein Hieronymus , Lawrjaniec Didier , Smith David A. , Truman Chris E. , Ohms D. Carsten , Smith Mike C. , Youtsos Anastasius G. , Cardamone David
Published: August 2008

ENPOWER is a EURATOM collaborative research project sponsored by the European Union. The aim is to produce advanced weld repair techniques and residual stress mitigation procedures for nuclear components in order to eliminate the need for expensive global Post-Weld Heat Treatment (PWHT). These procedures are based on weld repair optimisation combined with novel Alternative Post Weld Treatments (APWT). Repair procedures have been developed by carrying out parametric numerical studies for various repair and component configurations. APWTs are based on local heating at moderate temperatures (300–600°C) to produce local plasticity that redistributes the internal stresses and results in compression in the areas of interest. Two techniques have been identified as prime candidates: namely “hot compression” and “thermal shock” techniques. In combination with internal pressure the hot compression technique reveals itself to be very efficient and of most general use. The thermal shock method is effective for repairs in sections up to 25mm thick. The APWTs were established using numerical models applied to mock-up nuclear components, and validated by measurements. Numerical modelling methods have also been used to study the interactions between residual stresses, post weld treatments, operational loads, crack growth and fracture. Integrity assessment procedures using a modified J-integral definition are applied to confirm that optimised repair and APWT procedures can be developed to reduce welding residual stresses without any secondary detrimental effect, even with the presence of pre-existing cracks.
High Temperature Ultrasonic Examination and Sizing of Thermal Fatigue Cracking in Reactor Effluent Piping
Authors: McMillan John D. , Vollert David K.
Published: August 2008

Thermal fatigue cracking is a phenomenon found in many of the refining and petrochemical industry processes. It may occur in any grade of steel including carbon and stainless grades where extensive cycling of hot and cool processes mixed. Damage occurs over time and has the potential to cause failures, which may be considered catastrophic due to the process and temperatures used.
Design and Application for a Constant Seating Stress Gasket
Authors: Jenco John
Published: August 2008

Gasketed joints suffer from numerous performance issues relating to gasket design or installation. These include creep relaxation of the sealing material and, in the case of spiral-wound gaskets, unwinding or buckling of the inner ring or windings such that the sealing elements may extrude into the flow path, thereby damaging downstream components. These are sometimes exacerbated by various closure design factors or system operating conditions, such as piping misalignment, system thermal cycling, or high system vibration. A new gasket design, the constant seating stress gasket, addresses all of the common issues that have traditionally caused in-service leakage in gasketed joints. In addition, as its name implies, it also results in a uniform gasket seating stress radially across the entire sealing surface. This presentation discusses the key concepts underlying this revolutionary gasket design, as well as its application in mitigating several common causes of in-service gasketing failure.
Laser Shock Processing: Applications and Future Trends in U.S. Air Force Service
Authors: Shepard M. J.
Published: August 2008

To date, the United States Air Force is the largest end-user of laser shock processing services. Laser shock processing (LSP) is in successful day-to-day service and production for several USAF engine lines for increased foreign object damage tolerance. In this application LSP has yielded substantial increases in foreign object damage tolerance along with associated increases in safety. The history and current application of laser shock processing for US Air Force applications will be reviewed. Current and future USAF applications of laser shock processing and other surface treatments will be reviewed.
Risk-Based Assessment and Reliability Data Center
Authors: Cho Bill
Published: August 2008

Envisioning future activities for U.S. Hydrogen Economy, it is required to establish a broad consensus for building a viable and comprehensive national Hydrogen Codes and Standards, coupled with the establishment of “Safety & Reliability Data Center”.
Predicting the path of a changing sound: Velocity tracking and auditory continuity
Authors: Crum Poppy A. C. , Hafter Ervin R.
Published: August 2008

Three studies demonstrate listeners’ ability to use the rate of a sound’s frequency change (velocity) to predict how the spectral path of the sound is likely to evolve, even in the event of an occlusion. Experiments 1 and 2 use a modified probe-signal method to measure attentional filters and demonstrate increased detection to sounds falling along implied paths of constant-linear velocity. Experiment 3 shows listeners perceive a suprathreshold tone as falling along a trajectory of constant velocity when the frequency is near to the region of greatest detection as measured in Experiments 1 and 2. Further, results show greater accuracy and decreased bias in the use of velocity information with increased exposure to a constant-velocity sound. As the duration of occlusion lengthens, results also show a downward shift (relative to a trajectory of constant velocity) in the frequency at which listeners’ detection and experience of a continuous trajectory are greatest. A preliminary model of velocity processing is proposed to account for this downward shift. Results show listeners’ use of velocity in extrapolating sounds with dynamically changing spectral and temporal properties and provide evidence for its role in perceptual auditory continuity within a noisy acoustic environment.
Edge resonance in semi-infinite thick pipe: Numerical predictions and measurements
Authors: Ratassepp M. , Klauson A. , Chati F. , Léon F. , Maze G.
Published: August 2008

This paper presents theoretical and experimental studies of axisymmetric longitudinal guided wave L(0,2) interaction with the free edge of the pipe. A numerical method based on normal mode superposition is applied to predict the edge resonance by an analysis of dispersion relations of separate modes. In parallel, the finite element analysis and experimental measurements prove the existence of edge resonance in the pipe in case of L(0,2) wave incidence. It is shown that the edge resonance is mainly caused by the first pair of complex modes. Additionally the behavior of edge resonance phenomenon as a function of the curvature of the pipe is studied. The displacement amplitudes measured at the edge demonstrate that the edge resonance is affected by the frequency and thickness to midradius ratio of the pipe, and it is losing its strength in thicker pipes, as the growing difference between the outer and inner radii destroys symmetry. The reflected energy amplitudes show that at the resonance frequencies the incident wave is strongly converted to L(0,1) and L(0,3) modes, depending also on the curvature parameter of the pipe.
Smart panel with active damping units. Implementation of decentralized control
Authors: Díaz Cristóbal González , Paulitsch Christoph , Gardonio Paolo
Published: August 2008

This paper contains the second part of a study on a smart panel with five decentralized velocity feedback control units using proof mass electrodynamic actuators [González Díaz et al., J. Acoust. Soc. Am. 124, 886 (2008)]. The implementation of five decentralized control loops is analyzed, both theoretically and experimentally. The stability properties of the five decentralized control units have been assessed with the generalized Nyquist criterion by plotting the loci of the eigenvalues of the fully populated matrix of frequency response functions between the five error signals and five input signals to the amplifiers driving the actuators. The control performance properties have been assessed in terms of the spatially averaged response of the panel measured with a scanning laser vibrometer and the total sound power radiated measured in an anechoic room. The two analyses have shown that reductions of up to 10dB in both vibration response and sound radiation are measured at low audio frequencies, below about 250Hz.
Tank measurements of scattering from a resin-filled fiberglass spherical shell with internal flaws
Authors: Tesei Alessandra , Guerrini Piero , Zampolli Mario
Published: August 2008

This paper presents results of acoustic inversion and structural health monitoring achieved by means of low to midfrequency elastic scattering analysis of simple, curved objects, insonified in a water tank. Acoustic elastic scattering measurements were conducted between 15 and 100kHz on a 60-mm-radius fiberglass spherical shell, filled with a low-shear-speed epoxy resin. Preliminary measurements were conducted also on the void shell before filling, and on a solid sphere of the same material as the filler. These data were used to estimate the constituent material parameters via acoustic inversion. The objects were measured in the backscatter direction, suspended at midwater, and insonified by a broadband directional transducer. From the inspection of the response of the solid-filled shell it was possible to detect and characterize significant inhomogeneities of the interior (air pockets), the presence of which were later confirmed by x-ray CT scan and ultrasound measurements. Elastic wave analysis and a model–data comparison study support the physical interpretation of the measurements.
Spectrogram denoising and automated extraction of the fundamental frequency variation of dolphin whistles
Authors: Mallawaarachchi Asitha , Ong S. H. , Chitre Mandar , Taylor Elizabeth
Published: August 2008

Marine mammal vocalizations are often analyzed using time-frequency representations (TFRs) which highlight their nonstationarities. One commonly used TFR is the spectrogram. The characteristic spectrogram time-frequency (TF) contours of marine mammal vocalizations play a significant role in whistle classification and individual or group identification. A major hurdle in the robust automated extraction of TF contours from spectrograms is underwater noise. An image-based algorithm has been developed for denoising and extraction of TF contours from noisy underwater recordings. An objective procedure for measuring the accuracy of extracted spectrogram contours is also proposed. This method is shown to perform well when dealing with the challenging problem of denoising broadband transients commonly encountered in warm shallow waters inhabited by snapping shrimp. Furthermore, it would also be useful with other types of broadband transient noise.
Laboratory studies of near-grazing impulsive sound propagating over rough water
Authors: Qin Qin , Lukaschuk Sergei , Attenborough Keith
Published: August 2008

Acoustic impulses due to an electrical spark source (main acoustic energy near 15kHz) have been measured after propagating near to the water surface in a shallow container resting on a vibrating platform. Control of the platform vibration enabled control of water wave amplitudes. Analysis of the results reveals systematic variations in the received acoustic waveforms as the mean trough-to-crest water wave amplitude is increased up to 7mm. The amplitudes of the peaks corresponding to specular reflections are reduced and the variability in the tails of the waveforms is increased.
Flaw localization in a structure using model-based backpropagation.
Authors: Chambers David , Lehman Sean , Hagler Lisle , Hsieh Henry , Fisher Karl
Published: August 2008

Damage localization is an important part of structural health monitoring. In this talk we present the results of a method of localizing pointlike damage in a structure using changes in the vibrational response induced by the damage. The vibrational response is measured at discrete locations on a structure both before and after damage is induced. The difference in response is used to drive a numerical model of the undamaged structure (backpropagation). The damage location is marked by a peak in the calculated displacement field. Results are shown using laboratory measurements of a cylinder and two nested spherical half-shells. Numerical simulation is used to demonstrate performance in more complex structures. [Work supported by the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.]
Intonational interference on the perception and production of Mandarin Chinese tones by English-speaking second language learners.
Authors: Hao Yen-Chen
Published: August 2008

Most previous studies on L1 transfer focus on segments. The present study investigated the effect of L1 intonation on English speakers’ acquisition of Mandarin Chinese tones. Four intermediate learners read three sentence types: declaratives, yes/no questions, and a list sequence, both in English and Chinese. Their productions showed Tone 3 (low) to Tone 2 (rising), and Tone 4 (falling) to Tone 1 (high) errors, as expected if productions have a (English) terminal rise imposed on them. Nonfinal items in reading a list exhibited similar errors. In the perception task, subjects listened to Chinese productions of the different sentence types and identified the tone and whether the sentence is a statement or a question. When subjects identified a sentence as a question, they tended to judge the final tone to be Tone 2 (rising) or Tone 1 (high). Similarly, with final Tone 2, subjects usually called the sentence a question; and with final Tone 4, subjects often judged it as a declarative. English-speaking learners associate the rising tone with questions and falling tone with declaratives, even though they know the final word can carry any tone in Chinese. This study quantitatively documents an effect of intonation on the learning of lexical tones.
Identification of the Smallest Structure Capable of Evoking Opsonophagocytic Antibodies against
Streptococcus pneumoniae
Type 14
Authors: Safari Dodi , Dekker Huberta A. T. , Joosten John A. F. , Michalik Dirk , de Souza Adriana Carvalho , Adamo Roberto , Lahmann Martina , Sundgren Andreas , Oscarson Stefan , Kamerling Johannis P. , Snippe Harm
Published: August 2008

Synthetic overlapping oligosaccharide fragments of
Streptococcus pneumoniae
serotype 14 capsular polysaccharide (Pn14PS), {6)-[β-
d
-Gal
p
-(1→4)-]β-
d
-Glc
p
NAc-(1→3)-β-
d
-Gal
p
-(1→4)-β-
d
-Glc
p
-(1→}
n
, were conjugated to CRM
197
protein and injected into mice to determine the smallest immunogenic structure. The resulting antibodies were then tested for Pn14PS specificity and for their capacity to promote the phagocytosis of
S. pneumoniae
type 14 bacteria. Earlier studies have reported that the oligosaccharide corresponding to one structural repeating unit of Pn14PS, i.e., Gal-Glc-(Gal-)GlcNAc, induces a specific antibody response to Pn14PS. The broader study described here, which evaluated 16 oligosaccharides, showed that the branched trisaccharide element Glc-(Gal-)GlcNAc is essential in inducing Pn14PS-specific antibodies and that the neighboring galactose unit at the nonreducing end contributes clearly to the immunogenicity of the epitope. Only the oligosaccharide conjugates that produce antibodies recognizing Pn14PS were capable of promoting the phagocytosis of
S. pneumoniae
type 14. In conclusion, the branched tetrasaccharide Gal-Glc-(Gal-)GlcNAc may be a serious candidate for a synthetic oligosaccharide conjugate vaccine against infections caused by
S. pneumoniae
type 14.
Modular Arrangement of Allelic Variants Explains the Divergence in
Moraxella catarrhalis
UspA Protein Function
Authors: Brooks Michael J. , Sedillo Jennifer L. , Wagner Nikki , Laurence Cassie A. , Wang Wei , Attia Ahmed S. , Hansen Eric J. , Gray-Owen Scott D.
Published: August 2008

Ubiquitous surface protein A molecules (UspAs) of
Moraxella catarrhalis
are large, nonfimbrial, autotransporter proteins that can be visualized as a “fuzzy” layer on the bacterial surface by transmission electron microscopy. Previous studies attributed a wide array of functions and binding activities to the closely related UspA1, UspA2, and/or UspA2H protein, yet the molecular and phylogenetic relationships among these activities remain largely unexplored. To address this issue, we determined the nucleotide sequence of the
uspA1
genes from a variety of independent
M. catarrhalis
isolates and compared the deduced amino acid sequences to those of the previously characterized UspA1, UspA2, and UspA2H proteins. Rather than being conserved proteins, we observed a striking divergence of individual UspA1, UspA2, and UspA2H proteins resulting from the modular assortment of unrelated “cassettes” of peptide sequence. The exchange of certain variant cassettes correlates with strain-specific differences in UspA protein function and confers differing phenotypes upon these mucosal surface pathogens.
Patterns of Timing and Size of Wild Coho Salmon (Oncorhynchus kisutch) Smolts Migrating from the Keogh River Watershed on Northern Vancouver Island
Authors: Irvine J. R. , Ward B. R.
Published: August 2008

Coho salmon (Oncorhynchus kisutch) smolts leaving the Keogh River and its tributaries demonstrated consistent patterns in their timing and size. An initial early peak in the mean size of migrating smolts occurred several weeks before the peak in their timing, and in several years when smolt migration was monitored until July, a late peak in size occurred near the end of the smolt migration. Changes in the mean size of smolts were not related to their origin within the watershed, and varying age compositions were only partially responsible for the two peaks in mean size. Fish overwintering in tributary lakes grew faster than fish overwintering in tributary streams. A greater proportion of lake-origin smolts migrated to sea after only 1 yr in freshwater than stream-origin smolts. It appears that fish that wait until their second spring to smoltify are among the first to emigrate that spring. These relatively large 2 + smolts, combined with fast growing 1 + smolts that leave early during their first spring, cause the first peak in size. The small numbers of large smolts leaving the Keogh River at the ends of several of the smolt runs apparently left then because of minor flow increases in the river. As has been found with releases of coho smolts from nearby hatcheries, fish that left the Keogh River early in the smolt run generally had a more northerly marine catch distribution than later migrating smolts. A greater proportion of fish migrating to sea late in the smolt run were caught in the fishery than fish migrating early. Additional work examining the marine survival of early and late migrating wild smolts is recommended to enable detailed comparisons to be made between the optimal timing and size of wild and hatchery smolts.
Dietary Lipid as a Factor Modulating Xenobiotic Metabolism in Channel Catfish (Ictalurus punctatus)
Authors: Ankley Gerald T. , Blazer Vicki S. , Plakas Steven M. , Reinert Robert E.
Published: August 2008

Adult channel catfish (Ictalurus punctatus) were fed diets containing menhaden oil (MHO), soybean oil (SBO), or beef tallow (BFT) as lipid sources for 116 d. The effects of these diets on two important hepatic xenobiotic-metabolizing enzyme systems, cytochrome P-450-dependent monooxygenases (MOs) and glutathione S-transferases (GSTs), were evaluated. Microsomal MO and cytosolic GST activities were consistently greater in fish fed MHO than in those receiving SBO or BFT. Generally, enzyme activities in fish fed SBO and BFT were similar. The different diets also markedly influenced the fatty acid composition of the liver, particularly with respect to the relative abundance of specific fatty acid families. These data demonstrate that dietary lipid does affect the activities of xenobiotic-metabolizing enzymes in fishes, and thereby could influence the sensitivity of fishes to certain organic toxicants.
Comparaison des relations trophiques de Ruditapes philippinarum en milieux estuarien et océanique à partir d'un modèle de croissance
Authors: Bacher C. , Goulletquer P.
Published: August 2008

A comparison of trophic relationships for Ruditapes philippinarum in estuarine and oceanic areas: the use of a growth model. Trophic relationships in Ruditapes philippinarum were studied in estuarine and oceanic areas of Marennes-Oleron during 1985 and 1986. Principal components analysis (P.C.A.) was used to reveal the fluctuations of the descriptors from the principal axes. Changes in dry weight were predicted in each area through an allometric growth model and were related to the principal axes derived from the P.C.A. The results of the model were used to compare the growth in each area and to point out the descriptors responsible for the discrepancies, such as autumnal blooms or silt resuspension. Attention was paid to the sampling strategy related to the time scale of the phenomena accounting for trophic relationships.
Lethality of Low pH and Al to Early Life Stages of Six Fish Species Inhabiting PreCambrian Shield Waters in Ontario
Authors: Holtze K. E. , Hutchinson N. J.
Published: August 2008

Lethality of low pH and Al to egg and fry stages of common shiner (Notropis cornutus), white sucker (Catostomus commersoni), walleye (Stizostedion vitreum), lake whitefish (Coregonus clupeaformis), smallmouth bass (Micropterus dolomieui), and largemouth bass (M. salmoides) was determined in a series of laboratory tests in soft (Ca = 4.0 mg/L) water. Low pH was lethal to cleavage eggs in the first 4 d of exposure, to eyed eggs in the immediate prehatch period and to fry following their transition to branchial respiration. Early life stage response to Al was determined by their sensitivity to low pH. Al prolonged survival of cleavage eggs at pH = 4.2, was detrimental to eyed eggs and fry at pH 4.4–5.4 and was most lethal within 0.3 pH units of the pH which was lethal in the absence of Al. In situ distribution of four of the six species was adequately explained by lethality of low pH alone to cleavage eggs or fry. Sensitivity to low pH and Al produced estimates of pH > 5.9 (common shiner), pH > 5.4 (lake whitefish, white sucker, walleye), and pH > 5.1 (smallmouth and largemouth bass) for survival of early life stages in acidified waters.
Morphological Deformities in Larvae of Procladius Skuse (Diptera: Chironomidae) and Their Biomonitoring Potential
Authors: Warwick W. F.
Published: August 2008

Morphological deformities in Procladius larvae from sites in eastern and western Canada are described and compared. A framework for categorizing deformities in individual head capsule structures is presented to serve as a basis for indexing the severity of individual deformities and, eventually, to provide a more accurate measure of community response to contaminants. Comparison of morphological responses between Chironomus and Procladius suggest that Procladius is the more tolerant of environmental contaminants. It is proposed to use these differences in response to extend the range over which contaminant concentrations can be monitored.
CURRENT PROSPECTS FOR ASTROD INERTIAL SENSOR
Authors: PULIDO PATÓN A.
Published: August 2008

The Astrodynamical Space Test of Relativity using Optical Devices (ASTROD) is a multi-purpose relativity mission concept. ASTROD's scientific goals are the measurement of relativistic and solar system parameters to unprecedented precision, and the detection and observation of low-frequency gravitational waves to frequencies down to 5 × 10-6 Hz. To accomplish its goals, ASTROD will employ a constellation of drag-free satellites, aiming for a residual acceleration noise of (0.3-1) × 10-15 m s-2 Hz-1/2 at 0.1 mHz. Noise sources and strategies for improving present acceleration noise levels are reported.
ASTROMETRY AND ASTROPHYSICS WITH THE SPACE TELESCOPE RADIOASTRON
Authors: ZAKHAROV ALEXANDER F.
Published: August 2008

It is well-known that gravitational lensing is a powerful tool in the investigation of the distribution of matter, including that of dark matter (DM). Typical angular distances between images and typical time scales depend on the gravitational lens masses. For the case of microlensing, angular distances between images or typical astrometric shifts are about 10-5 - 10-6 arcsec. Such an angular resolution will be reached with the space–ground VLBI interferometer, Radioastron. The basic targets for microlensing searches should be bright point-like radio sources at cosmological distances. In this case, an analysis of their variability and a solid determination of microlensing could lead to an estimation of their cosmological mass density. Moreover, one could not exclude the possibility that non-baryonic dark matter could also form microlenses if the corresponding optical depth were high enough. It is known that in gravitationally lensed systems the probability (the optical depth) of observing microlensing is relatively high. Therefore, for example, gravitationally lensed objects, like the CLASS gravitational lens B1600+434, appear to be most suitable to detect astrometric microlensing, since features of photometric microlensing have been detected in these objects. However, to directly resolve these images and to directly detect the apparent motion of the knots, the Radioastron sensitivity would have to be improved, since the estimated flux density is below the sensitivity threshold. Alternatively, they may be observed by increasing an integration time, assuming that a radio source has a typical core–jet structure and microlensing phenomena are caused by the superluminal apparent motions of knots. In the case of a confirmation (or a negation) of claims about microlensing in gravitational lens systems, one can speculate about the microlens contribution to the gravitational lens mass. Astrometric microlensing due Galactic MACHOs is not very important because of low optical depths and long typical time scales. Therefore, the launch of the space interferometer Radioastron will enable the investigation of microlensing in the radio band, giving rise to the possibility of not only resolving microimages but also of observing astrometric microlensing.
RELIC GRAVITATIONAL WAVES AND CMB POLARIZATION IN THE ACCELERATING UNIVERSE
Authors: ZHANG Y. , ZHAO W. , XIA T. Y. , ER X. Z. , MIAO H. X.
Published: August 2008

In this paper we briefly present our work on relic gravitational waves (RGW) and the CMB polarization in the accelerating universe. The spectrum of RGW has been obtained, showing the influence of dark energy. Compared with those from non-accelerating models, the shape of the spectrum is approximately similar, nevertheless, the amplitude of RGW now acquires a suppressing factor of the ratio of matter over dark energy ∝ Ωm/ΩΛ ~ 0.4 over almost the whole range of frequencies. The RGW Spectrum is then used as the source to calculate the spectra of CMB polarization. By using two half-Gaussian functions as an approximation to the visibility function during the photon decoupling, both the "electric" and "magnetic" spectra have been analytically derived and they are quite close to those obtained numerically. Several physical elements that affect the spectra have been examined, such as the decoupling process, inflation, dark energy, the baryons, etc.
Valerija Čepulyte (1904–1987) and her studies of the Quaternary formations in Lithuania
Authors: Kondratiene Ona , Stančikaite Migle
Published: August 2008

Valerija Čepulyte (1904–1987) devoted her life to the development and promotion of geographical/geological research in Lithuania. The different aspects of Quaternary stratigraphy, palaeogeography, extent of the Last Glacial (Weichselian) and deglaciation of the territory, together with the development of the geomorphological terminology and methodology of the geomorphological mapping, were of primary interest to her during her long scientific career. Graduating from Vilnius University in 1939, Čepulyte became the first woman in Lithuania to take a doctoral degree in geographical science (1948) and in 1968 she was awarded the Doctor Habilitus degree. Her scientific innovations and ideas were important for generations of research workers dealing with the Quaternary system both in Lithuania and abroad.
Evolution of the theory of continental glaciation in northern and eastern Europe
Authors: Raukas Anto
Published: August 2008

The theory of continental glaciation was worked out independently in different countries, but the idea that glaciers had formerly expanded over much larger areas than today was born in Switzerland (Venetz-Sitten, von Charpentier, Agassiz
et al.
). From the region of ‘living glaciers’ in the Alps, scientists could make direct comparisons between areas now occupied by ice and those evidently abandoned by ice. Otto Torell in northern Europe and Piotr Kropotkin in Russia are most often named the ‘fathers’ of the glacial theory. But, in fact, Karl Eduard Eichwald (1795–1876) was the first in the Russian Baltic provinces to consider the possibility of the wide distribution of ice in lowland areas. The glacial theory was strongly supported by the academician Friedrich Schmidt (1832–1908), and features of several glaciations in northern and eastern Europe were first mentioned by Constantin Grewingk in 1879.
Porous flow in particle-based fluid simulations
Authors: Lenaerts Toon , Adams Bart , Dutré Philip
Published: August 2008

This paper presents the simulation of a fluid flowing through a porous deformable material. We introduce the physical principles governing porous flow, expressed by the Law of Darcy, into the Smoothed Particle Hydrodynamics (SPH) framework for simulating fluids and deformable objects. Contrary to previous SPH approaches, we simulate porous flow at a macroscopic scale, making abstraction of individual pores or cavities inside the material. Thus, the number of computational elements is kept low, while at the same time realistic simulations can be achieved. Our algorithm models the changing behavior of the wet material as well as the full two-way coupling between the fluid and the porous material. This enables various new effects, such as the simulation of sponge-like elastic bodies and water-absorbing sticky cloth.
A perception-based color space for illumination-invariant image processing
Authors: Chong Hamilton Y. , Gortler Steven J. , Zickler Todd
Published: August 2008

Motivated by perceptual principles, we derive a new color space in which the associated metric approximates perceived distances and color displacements capture relationships that are robust to spectral changes in illumination. The resulting color space can be used with existing image processing algorithms with little or no change to the methods.
Watertight trimmed NURBS
Authors: Sederberg Thomas W. , Finnigan G. Thomas , Li Xin , Lin Hongwei , Ipson Heather
Published: August 2008

This paper addresses the long-standing problem of the unavoidable gaps that arise when expressing the intersection of two NURBS surfaces using conventional trimmed-NURBS representation. The solution converts each trimmed NURBS into an untrimmed T-Spline, and then merges the untrimmed T-Splines into a single, watertight model. The solution enables watertight fillets of NURBS models, as well as arbitrary feature curves that do not have to follow iso-parameter curves. The resulting T-Spline representation can be exported without error as a collection of NURBS surfaces.
Announcements
Authors: Lee Newton
Published: August 2008

1. Facial and Bodily Expressions for Control and Adaptation of Games (ECAG '08)

2. The Fourth Conference on Artificial Intelligence and Interactive Digital Entertainment

3. Gaming 2008: Design For Engaging Experience And Social Interaction

4. Artificial Intelligence for Computer Games

5. Workshop on Network and Systems Support for Games: NetGames 2008

6. Workshop on Artful applications in Ambient TV
Prefabrication and postfabrication architecture exploration for partially reconfigurable VLIW processors
Authors: Chattopadhyay A. , Ishebabi H. , Chen X. , Rakosi Z. , Karuri K. , Kammler D. , Leupers R. , Ascheid G. , Meyr H.
Published: August 2008

Modern application-specific instruction-set processors (ASIPs) face the daunting task of delivering high performance for a wide range of applications. For enhancing the performance, architectural features, for example, pipelining, VLIW, are often employed in ASIPs, leading to high design complexity. Integrated ASIP design environments, like template-based approaches and language-driven approaches, provide an answer to this growing design complexity. At the same time, increasing hardware design costs have motivated the processor designers to introduce high flexibility in the processor. Flexibility, in its most effective form, can be introduced to the ASIP by coupling a reconfigurable unit to the base processor. Because of its obvious benefits, several reconfigurable ASIPs (rASIPs) have been designed for years. This design paradigm gained momentum with the advent of coarse-grained FPGAs, where the lack of domain-specific performance common in general-purpose FPGAs are largely overcome by choosing application-dependent basic functional units. These rASIP designs lack a generic flow from high-level specification, resulting in intuitive design decisions and hard-to-retarget processor design tools. Although partial, template-based approaches for rASIP design is existent, a clear design methodology especially for the prefabrication architecture exploration is not present. In order to address this issue, a high-level specification and design methodology for partially reconfigurable VLIW processors is proposed in this article. To show the benefit of this approach, a commercial VLIW processor is used as the base architecture and two domains of applications are studied for potential performance gain.
Modeling and analysis of core-centric network processors
Authors: Lin Yi-Neng , Lin Ying-Dar , Lai Yuan-Cheng , Tseng Kuo-Kun
Published: August 2008

Network processors can be categorized into two types, the coprocessors-centric model in which data-plane is handled by coprocessors, and the core-centric model in which the core processes most of the data-plane packets yet offloading some tasks to coprocessors. While the former has been properly explored over various applications, research regarding the latter remain limited. Based on the previous experience of prototyping the virtual private network (VPN) over the IXP425 network processor, this work aims to derive design implications for the core-centric model performing computational intensive applications. From system and IC vendors' perspectives, the continuous-time Markov chain and Petri net simulations are adopted to explore this architecture. Analytical results prove to be quite inline with those of the simulation and implementation. With subsequent investigation, we find that appropriate process run lengths can improve the effective core utilization by 2.26 times, and by offloading the throughput boosts 7.5 times. The results also suggest single-process programming, since context-switch overhead impacts considerably on the performance.
Register allocation for software pipelined multidimensional loops
Authors: Rong Hongbo , Douillet Alban , Gao Guang R.
Published: August 2008

This article investigates register allocation for software pipelined multidimensional loops where the execution of successive iterations from an
n
-dimensional loop is overlapped. For single loop software pipelining, the lifetimes of a loop variable in successive iterations of the loop form a repetitive pattern. An effective register allocation method is to represent the pattern as a vector of lifetimes (or a vector lifetime using Rau's terminology [Rau 1992]) and map it to rotating registers. Unfortunately, the software pipelined schedule of a multidimensional loop is considerably more complex and so are the vector lifetimes in it.

In this article, we develop a way to normalize and represent the vector lifetimes, which captures their complexity, while exposing their regularity that enables a simple solution. The problem is formulated as bin-packing of the multidimensional vector lifetimes on the surface of a space-time cylinder. A metric, called distance, is calculated either conservatively or aggressively to guide the bin-packing process, so that there is no overlapping between any two vector lifetimes, and the register requirement is minimized. This approach subsumes the classical register allocation for software pipelined single loops as a special case. The method has been implemented in the ORC compiler and produced code for the IA-64 architecture. Experimental results show the effectiveness. Several strategies for register allocation are compared and analyzed.
Homomorphism preservation theorems
Authors: Rossman Benjamin
Published: August 2008

The homomorphism preservation theorem (h.p.t.), a result in classical model theory, states that a first-order formula is preserved under homomorphisms on all structures (finite and infinite) if and only if it is equivalent to an existential-positive formula. Answering a long-standing question in finite model theory, we prove that the h.p.t. remains valid when restricted to finite structures (unlike many other classical preservation theorems, including the Łoś--Tarski theorem and Lyndon's positivity theorem). Applications of this result extend to constraint satisfaction problems and to database theory via a correspondence between existential-positive formulas and unions of conjunctive queries. A further result of this article strengthens the classical h.p.t.: we show that a first-order formula is preserved under homomorphisms on all structures if and only if it is equivalent to an existential-positive formula
of equal quantifier-rank
.
Scheduling in multihop WiMAX networks
Authors: Ghosh Debalina , Gupta Ashima , Mohapatra Prasant
Published: August 2008

IEEE 802.16, popularly known as WiMAX, is at the forefront of the technology drive because of the growing demand for high-speed wireless broadband networks. Multihop WiMAX networks are particularly useful as they increase the coverage area without the need to deploy expensive base stations. There are two kinds of multihop WiMAX networks - WiMAX mesh and Mobile Multihop Relay Networks. Scheduling is very important in both of these multihop WiMAX networks. The links have to be scheduled in such a way so that they do not interfere with each other while maximizing the throughput of the networks. As WiMAX networks are geared towards broadband applications, any scheduling scheme should accomodate the rate, latency and jitter requirements of the applications. This article provides an insight to the scheduling framework presented in the IEEE 802.16 standard. It also presents a few representative research proposals for centralized scheduling in WiMAX networks. We discuss some of the research issues and challenges that need to be addressed for multihop WiMAX networks to realize their full potential.
Localized sensor self-deployment with coverage guarantee
Authors: Li Xu , Frey Hannes , Santoro Nicola , Stojmenovic Ivan
Published: August 2008

We pinpoint a new sensor self-deployment problem, achieving focused coverage around a Point of Interest (POI), and introduce an evaluation metric, coverage radius. We propose two purely localized solution protocols Greedy Advance (GA) and Greedy-Rotation-Greedy (GRG), both of which are resilient to node failures and work regardless of network partition. The two algorithms drive sensors to move along a locally-computed triangle tessellation (TT) to surround the POI. In GA, nodes greedily proceed as close to the POI as they can; in GRG, when their greedy advance is blocked, nodes rotate around the POI to a TT vertex where greedy advance can resume. They both yield a connected network of TT layout with hole-free coverage. Further, GRG ensures a hexagon coverage shape centered at the POI.
MIRA
Authors: Park Dongkook , Eachempati Soumya , Das Reetuparna , Mishra Asit K. , Xie Yuan , Vijaykrishnan N. , Das Chita R.
Published: August 2008

Recently, Network-on-Chip (NoC) architectures have gained popularity to address the interconnect delay problem for designing CMP / multi-core / SoC systems in deep sub-micron technology. However, almost all prior studies have focused on 2D NoC designs. Since three dimensional (3D) integration has emerged to mitigate the interconnect delay problem, exploring the NoC design space in 3D can provide ample opportunities to design high performance and energy-efficient NoC architectures. In this paper, we propose a 3D stacked NoC router architecture, called MIRA, which unlike the 3D routers in previous works, is stacked into multiple layers and optimized to reduce the overall area requirements and power consumption. We discuss the design details of a four-layer 3D NoC and its enhanced version with additional express channels, and compare them against a (6×6) 2D design and a baseline 3D design. All the designs are evaluated using a cycle-accurate 3D NoC simulator, and integrated with the Orion power model for performance and power analysis. The simulation results with synthetic and application traces demonstrate that the proposed multi-layered NoC routers can outperform the 2D and naïve 3D designs in terms of performance and power. It can achieve up to 42% reduction in power consumption and up to 51% improvement in average latency with synthetic workloads. With real workloads, these benefits are around 67% and 38%, respectively.
Procurement platforms for consumers
Authors: Klafft Michael
Published: August 2008

E-procurement platforms have been widely used in business-to-business and business-to-government transactions for many years. More recently, such platforms have become available for consumers as well. However, the question is if such platforms will be as beneficial in a consumer context as they have been in B2B and B2G before. By summarizing recent results from empirical studies and from focus group interviews with platform users, this paper discusses benefits and risks which using e-procurement platforms brings about for the often inexperienced consumer. Current market trends are presented, key obstacles for platform acceptance are identified, and recommendations for future platform development are provided.
Imitation-based evolution of artificial game players
Authors: Priesterjahn Steffen
Published: August 2008

Because of the rapid progress of commercial computer games in recent years the development of artificial characters that inhabit the presented game worlds has become a challenging task with very specific requirements. A particular computer game specific requirement is that, as the objective of computer games is the entertainment of the player, the artificial intelligence should not only be competitive but also show intelligent and human-like behaviours. Therefore, the following article proposes the usage of imitation techniques to generate more human-like behaviours in an action game, whereas the imitation is achieved by recording players and by using these recordings as the basis of an evolutionary learning approach.
Competitions @ WCCI-2008
Authors: Loiacono Daniele , Togelius Julian
Published: August 2008

The Simulated Car Racing Competition was organized in conjunction with WCCI-2008, the IEEE World Congress on Computational Intelligence. The competition was the spiritual successor of the previous car racing competition held at CIG-2007 (the IEEE Conference on Computational Intelligence and Games) and CEC-2007 (the IEEE Congress on Evolutionary Computation). The goal of this year's competition was to learn, or otherwise design a controller for The Open Racing Car Simulator (TORCS), a state-of-the-art, open source, car racing simulator, which could be able to race for a certain number of laps on a set of three unknown tracks, alone or against other drivers.
Neural network Othello competition
Authors: Lucas Simon M.
Published: August 2008

IEEE WCCI 2008 also saw the latest instalment of the Neural Network Othello competition. The aim of this is to find the best performing neural network (or more generally, any form of value function) for playing Othello. The mode of operation is as follows. Entrants submit their trained architectures to the competition web server, which evaluates them against a standard heuristic player, and immediately updates a league table with the performance of the submitted player. The leading entry by each entrant is then played off in a round robin league against the other leading entries to determine the competition winner. The competition server has been running for over two years now, and has received well over 1,000 entries. The IEEE CEC 2006 entry was won by an MLP (with a single hidden layer), submitted by Kyung-Joong Kim and Sung-Bae Cho of Yonsei University, Seoul, South Korea. In the league table below this entry is referred to as CEC 2006 Champ.
Lessons from Laparoscopic Liver Surgery: A Nine-Year Case Series
Authors: Spencer Laura , Metcalfe Matthew S. , Strickland Andrew D. , Elsey Elisabeth J. , Robertson Gavin S. , Lloyd David M.
Published: August 2008

Objective. This series describes a developing experience in laparoscopic liver surgery presenting results from 40 procedures including right hemihepatectomy, left lateral lobectomy, and microwave ablation therapy. Methods. Forty patients undergoing laparoscopic liver surgery between September 1997 and November 2006 were included. The data set includes: operative procedure and duration, intraoperative blood loss, conversion to open operation rates, length of hospital stay, complications, mortality, histology of lesions/resection margins, and disease recurrence. Results. Mean age of patient: 59 years, 17/40 male, 23/40 female, 23/40 of lesions were benign, and 17/40 malignant. Operations included: laparoscopic anatomical resections n=15, nonanatomical resections n=11, microwave ablations n=8 and deroofing of cysts n=7. Median anaesthetic time: 120 minutes (range 40–240), mean blood loss 78 mL and 1/40 conversions to open. Median resection margins were 10 mm (range 1–14) and median length of stay 3 days (range 1–10). Operative and 30-day mortality were zero with no local disease recurrence. Conclusion. Laparoscopic liver surgery appears safe and effective and is associated with reduced hospital stay. Larger studies are required to confirm it is oncologically sound.
Amplitude and Frequency Control: Stability of Limit Cycles in Phase-Shift and Twin-T Oscillators
Authors: Dada J. P. , Chedjou J. C. , Domngang S.
Published: August 2008

We show a technique for external direct current (DC) control of the amplitudes of limit cycles both in the Phase-shift and Twin-T oscillators. We have found that amplitudes of the oscillator output voltage depend on the DC control voltage. By varying the total impedance of each oscillator oscillatory network, frequencies of oscillations are controlled using potentiometers. The main advantage of the proposed circuits is that both the amplitude and frequency of the waveforms generated can be independently controlled. Analytical, numerical, and experimental methods are used to determine the boundaries of the states of the oscillators. Equilibrium points, stable limit cycles, and divergent states are found. Analytical results are compared with the numerical and experimental solutions, and a good agreement is obtained.