bluuebunny/crossref_metadata_2025 huggingface dataset:
Automatic source speaker selection for voice conversion
Authors: Turk Oytun , Arslan Levent M.
Published: January 2009

This paper focuses on the importance of source speaker selection for a weighted codebook mapping based voice conversion algorithm. First, the dependency on source speakers is evaluated in a subjective listening test using 180 different source-target pairs from a database of 20 speakers. Subjective scores for similarity to target speaker’s voice and quality are obtained. Statistical analysis of scores confirms the dependence of performance on source speakers for both male-to-male and female-to-female transformations. A source speaker selection algorithm is devised given a target speaker and a set of source speaker candidates. For this purpose, an artificial neural network (ANN) is trained that learns the regression between a set of acoustical distance measures and the subjective scores. The estimated scores are used in source speaker ranking. The average cross-correlation coefficient between rankings obtained from median subjective scores and rankings estimated by the algorithm is 0.84 for similarity and 0.78 for quality in male-to-male transformations. The results for female-to-female transformations were less reliable with a cross-correlation value of 0.58 for both similarity and quality.
Spectral weights for sample discrimination as a function of overall level
Authors: Leibold Lori J. , Tan Hongyang , Jesteadt Walt
Published: January 2009

Doherty and Lutfi [(1996). “Spectral weights for overall level discrimination in listeners with sensorineural hearing loss,” J. Acoust. Soc. Am. 99, 1053–1058] examined the weights assigned to individual components of a six-tone complex during a sample discrimination task and reported that hearing-impaired subjects gave the most weight to components in the region of their high-frequency hearing loss. In contrast, weighting patterns varied for normal-hearing subjects. In the current study, the same six-tone complex, comprised of the octave frequencies from 0.25 to 8 kHz, was presented to three subjects with normal hearing in high-pass noise, in low-pass noise, and in quiet at two overall levels. Consistent with Doherty and Lutfi, subjects assigned more weight to the 4-kHz component in the high-pass noise condition, but roughly equal weight to all components in the lower-level quiet condition. Weights in the low-pass noise and higher-level quiet conditions, however, were similar to those in the high-pass noise condition. A second experiment compared weights for seven subjects in quiet at four different mean levels. Weights for the highest-frequency components increased as the overall level of the complexes was increased. These results suggest that overall level, rather than degree of hearing loss or sensation level, was the primary cause of the effect that Doherty and Lutfi observed.
Fuzzy structure theory modeling of sound-insulation layers in complex vibroacoustic uncertain systems: Theory and experimental validation
Authors: Fernandez Charles , Soize Christian , Gagliardini Laurent
Published: January 2009

The fuzzy structure theory was introduced 20 years ago in order to model the effects of complex subsystems imprecisely known on a master structure. This theory was only aimed at structural dynamics. In this paper, an extension of that theory is proposed in developing an elastoacoustic element useful to model sound-insulation layers for computational vibroacoustics of complex systems. The simplified model constructed enhances computation time and memory allocation because the number of physical and generalized degrees of freedom in the computational vibroacoustic model is not increased. However, these simplifications introduce model uncertainties. In order to take into account these uncertainties, the nonparametric probabilistic approach recently introduced is used. A robust simplified model for sound-insulation layers is then obtained. This model is controlled by a small number of physical and dispersion parameters. First, the extension of the fuzzy structure theory to elastoacoustic element is presented. Second, the computational vibroacoustic model including such an elastoacoustic element to model sound-insulation layer is given. Then, a design methodology to identify the model parameters with experiments is proposed and is experimentally validated. Finally, the theory is applied to an uncertain vibroacoustic system.
Talkers alter vowel production in response to real-time formant perturbation even when instructed not to compensate
Authors: Munhall K. G. , MacDonald E. N. , Byrne S. K. , Johnsrude I.
Published: January 2009

Talkers show sensitivity to a range of perturbations of auditory feedback (e.g., manipulation of vocal amplitude, fundamental frequency and formant frequency). Here, 50 subjects spoke a monosyllable (“head”), and the formants in their speech were shifted in real time using a custom signal processing system that provided feedback over headphones. First and second formants were altered so that the auditory feedback matched subjects’ production of “had.” Three different instructions were tested: (1) control, in which subjects were naïve about the feedback manipulation, (2) ignore headphones, in which subjects were told that their voice might sound different and to ignore what they heard in the headphones, and (3) avoid compensation, in which subjects were informed in detail about the manipulation and were told not to compensate. Despite explicit instruction to ignore the feedback changes, subjects produced a robust compensation in all conditions. There were no differences in the magnitudes of the first or second formant changes between groups. In general, subjects altered their vowel formant values in a direction opposite to the perturbation, as if to cancel its effects. These results suggest that compensation in the face of formant perturbation is relatively automatic, and the response is not easily modified by conscious strategy.
Feasibility of global-scale synthetic aperture communications
Authors: Song H. C. , Dzieciuch M.
Published: January 2009

A recent paper [Higley et al., J. Acoust. Soc. Am. 118, 2365–2372 (2005)] investigated synthetic aperture communications in shallow water exploiting the relative motion between a source and a receiver. This letter presents a feasibility study of synthetic aperture communications at global distances using the 57Hz acoustic data from the Heard Island Feasibility Test conducted in January 1991 [Baggeroer and Munk, Phys. Today 45, 22–30 (1992)]. Specifically, a reception at Ascension Island, about 9200km from the source ship moving at about 3kt near Heard Island, is analyzed by treating the 255-digit m-sequence tomography signal as a binary-phase shift-keying communication signal with an information rate of 11.4bits∕s. The performance using a single receiver combining three consecutive receptions spaced 5.2min (∼470m) apart indicates that synthetic aperture acoustic communications is feasible at global distances.
Coherence function of a sound field in an oceanic waveguide with horizontally isotropic statistics
Authors: Voronovich A. G. , Ostashev V. E.
Published: January 2009

The mean value and the coherence function of a sound field propagating in an oceanic waveguide with random inhomogeneities are important statistical characteristics of this field, which are needed for many practical applications. Closed equations for the coherence function were obtained in many works for both two dimensional and three dimensional geometries. For the 3D case, these equations are too involved even for a numerical treatment. In this paper, explicit expressions for the mean field and the coherence function due to a point omnidirectional monochromatic source in a 3D waveguide are derived for the case of random inhomogeneities, which are statistically isotropic in a horizontal plane. The solutions are much simpler than those obtained previously due to the cylindrical symmetry of the problem. The theory developed is used to study numerically the mean field and the coherence function in an oceanic waveguide perturbed by a random field of internal waves with the Garrett–Munk spectrum.
Bone sonometry: Reducing phase aberration to improve estimates of broadband ultrasonic attenuation
Authors: Bauer Adam Q. , Anderson Christian C. , Holland Mark R. , Miller James G.
Published: January 2009

Previous studies suggest that phase cancellation at the receiving transducer can result in the overestimation of the frequency dependent ultrasonic attenuation of bone, a quantity that has been shown to correlate with bone mineral density and ultimately with osteoporotic fracture risk. Evidence supporting this interpretation is provided by phase insensitive processing of the data, which appear to reduce the apparent overestimates of attenuation. The present study was designed to clarify the components underlying phase aberration artifacts in such through-transmission measurements by conducting systematic studies of the simplest possible test objects capable of introducing phase aberration. Experimental results are presented for a Lexan phantom over the frequency range 300–700kHz and a Plexiglas phantom over the 3–7MHz range. Both phantoms were flat and parallel plates featuring a step discontinuity milled into one of their initially flat sides. The through-transmitted signals were received by a 0.6mm diameter membrane hydrophone that was raster scanned over a grid coaxial with the transmitting transducer. Signals received by the pseudoarray were processed offline to emulate phase sensitive and phase insensitive receivers with different aperture diameters. The data processed phase sensitively were focused to demonstrate the results of planar, geometrical, and correlation-based aberration correction methods. Results are presented illustrating the relative roles of interference in the ultrasonic field and phase cancellation at the receiving transducer in producing phase aberration artifacts. It was found that artifacts due to phase cancellation or interference can only be minimized with phase insensitive summation techniques by choosing an appropriately large receiving aperture. Data also suggest the potentially confounding role of time-and frequency-domain artifacts on ultrasonic measurements and illustrate the advantages of two-dimensional receiving arrays in determining the slope of attenuation (nBUA) for the clinical assessment of osteoporosis.
Modeling tone and intonation in Mandarin and English as a process of target approximation
Authors: Prom-on Santitham , Xu Yi , Thipakorn Bundit
Published: January 2009

This paper reports the development of a quantitative target approximation (qTA) model for generating F0 contours of speech. The qTA model simulates the production of tone and intonation as a process of syllable-synchronized sequential target approximation [Xu, Y. (2005). “Speech melody as articulatorily implemented communicative functions,” Speech Commun. 46, 220–251]. It adopts a set of biomechanical and linguistic assumptions about the mechanisms of speech production. The communicative functions directly modeled are lexical tone in Mandarin and lexical stress in English and focus in both languages. The qTA model is evaluated by extracting function-specific model parameters from natural speech via supervised learning (automatic analysis by synthesis) and comparing the F0 contours generated with the extracted parameters to those of natural utterances through numerical evaluation and perceptual testing. The F0 contours generated by the qTA model with the learned parameters were very close to the natural contours in terms of root mean square error, rate of human identification of tone, and focus and judgment of naturalness by human listeners. The results demonstrate that the qTA model is both an effective tool for research on tone and intonation and a potentially effective system for automatic synthesis of tone and intonation.
The contribution of temporal fine structure to the intelligibility of speech in steady and modulated noise
Authors: Hopkins Kathryn , Moore Brian C. J.
Published: January 2009

Speech reception thresholds were measured with steady and amplitude-modulated noise maskers for signals processed to contain variable amounts of temporal fine structure (TFS) information. Subjects benefited more from TFS information for the modulated than for the steady masker. For both maskers, addition of TFS information up to 548Hz improved performance, though the improvement was greater for the modulated masker. The addition of TFS information at higher frequencies improved performance further for the modulated masker only. These results are consistent with the idea that TFS information is important for listening in the dips of a fluctuating masker.
Magneto-mechanical impedance of metallic structures
Authors: Zagrai Andrei N.
Published: January 2009

Impedance measurements with a magneto-elastic active sensor are explored for inferring the magneto-mechanical impedance (MMI) of a metallic structure. It is shown that the MMI contains electrical response of the sensor and both electrical and mechanical structural responses. An analytical model is suggested that accounts for electrical characteristics of the sensor, sensor/structure electromagnetic interaction, and multimodal structural dynamic behavior. The model is validated with a set of MMI experiments demonstrating feasibility of deducing structural natural frequencies and structural vibration modes.
Sequential effects on the detectability of a tone added to a multitone masker
Authors: Cao Xiang , Huang Rong , Richards Virginia M.
Published: January 2009

The detectability of a tone added to a masker is superior when the detection trial is preceded by the masker than the signal-plus-masker. This auditory enhancement can withstand long temporal gaps between the precursor and the trial, suggesting that for yes/no trials sensitivity may depend on the stimulus presented in the prior trial. The results from an experiment examining the detectability of a 1000-Hz tone added to 6-tone maskers confirmed sequential effects on sensitivity. The values of d′ were higher when the prior trial was a no-signal (masker alone) trial compared to a signal (signal-plus-masker) trial.
Speaking up: Killer whales (Orcinus orca) increase their call amplitude in response to vessel noise
Authors: Holt Marla M. , Noren Dawn P. , Veirs Val , Emmons Candice K. , Veirs Scott
Published: January 2009

This study investigated the effects of anthropogenic sound exposure on the vocal behavior of free-ranging killer whales. Endangered Southern Resident killer whales inhabit areas including the urban coastal waters of Puget Sound near Seattle, WA, where anthropogenic sounds are ubiquitous, particularly those from motorized vessels. A calibrated recording system was used to measure killer whale call source levels and background noise levels (1–40kHz). Results show that whales increased their call amplitude by 1dB for every 1dB increase in background noise levels. Furthermore, nearby vessel counts were positively correlated with these observed background noise levels.
Centrifuge and numerical modeling of axial load effects on piles in consolidating ground
Authors: Lam S. Y. , Ng Charles W.W. , Leung C. F. , Chan S. H.
Published: January 2009

This paper reports the results of four centrifuge model tests that were undertaken to investigate behavior of floating piles subjected to negative skin friction (NSF) and to study effects of axial load on the load-transfer mechanism along single floating piles and shielded center piles inside a group of sacrificing piles. In addition, three-dimensional numerical analyses of the centrifuge model tests were carried out with elasto-plastic slip considered at the pile–soil interface. Prior to applying load, the measured neutral plane position of the single floating piles was located at approximately the three-quarter depth level of the embedded pile length. The neutral plane elevation shifts lower down the pile shaft as the distance of pile tip above the bearing stratum decreases. Under the application of axial load, the dragload generated by excessive soil settlement decreases and is eventually eliminated. The amount of axial load for complete NSF elimination does not seem to be significantly affected by the presence of sacrificing piles, but it does increase with end-bearing stiffness of the pile. Numerical simulation revealed that the hang-up effect is not altered by the application of axial load.
Radial consolidation with vertical drains and general time-dependent loading
Authors: Conte Enrico , Troncone Antonello
Published: January 2009

A simple-to-use analytical solution for radial consolidation with vertical drains under equal strain conditions is presented in this paper. This solution accounts for the effects of soil smear, drain hydraulic resistance, and general time-dependent loading. A number of comparisons with other theoretical methods are shown to assess the accuracy of the proposed solution, both in terms of excess pore-water pressure and degree of consolidation settlement. Moreover, two case histories documented in the literature are analysed to evaluate the main parameters affecting radial consolidation in the presence of vertical drains.
Modelling the erosion rate of chemically stabilized soil incorporating tensile force – deformation characteristics
Authors: Indraratna Buddhima , Muttuvel Thevaragavan , Khabbaz Hadi
Published: January 2009

To evaluate the safety of embankment dams, it is necessary to estimate the erosion rate based on common geotechnical properties such as shear and tensile strength. However, the empirical expressions that are currently available in the literature for this purpose are often inadequate. In this paper, an analytical model is developed to model the erosion of a soil capturing its tensile behaviour based on the law of energy conservation. The erosion rate can be determined using the proposed model if the tensile force – deformation characteristics, dry density, mean particle diameter, and mean flow velocity are known. The proposed model is semi-empirical and can be validated with experimental results obtained from the novel process simulation apparatus for internal crack erosion (PSAICE) designed and built at the University of Wollongong, Australia. All tests were conducted on erodible silty sand stabilized with cement and lignosulfonate. The model validation clearly indicates that only a fraction of the energy (efficiency index) from the water stream is effectively used for erosion.
Horizontal pressure on barricades for backfilled stopes. Part I: Fully drained conditions
Authors: Li Li , Aubertin Michel
Published: January 2009

Stope backfilling is used in underground mines to provide a safer working space for personnel and machinery. To ensure a secure application of backfill, it is critical to accurately evaluate the pressures exerted on the walls and barricades placed near the base of the stope to retain the fill materials. In this paper, existing solutions for evaluating the stresses on barricades are reviewed. The authors then propose a new three-dimensional analytical solution that takes into account the stress transfer from the backfill to the walls in both the stope and access drift. In particular, the solution considers the influence of the barricade position within the drift on the stress state. Comparisons are made between the proposed solution, physical model test results, and numerical simulations. The good agreement between various results indicates that the proposed formulation provides a good estimate of the pressure on a barricade. The solution presented here is applicable to fully drained backfill (without water-pore pressure); the solution for saturated backfill is given in a companion paper (see Part II, this issue).
Field variable-head test in low-permeability materials: Assessing the effects of trapped gas pocket and cavity expansion
Authors: Chapuis Robert P.
Published: January 2009

Trapped gas and cavity expansion may affect the data of a variable-head test in a monitoring well. In a low-permeability material, some gas may be trapped in the top of the filter pack. Presence of a gas pocket may be alleged when the initial change in water level in the pipe is less than the theoretical value due to the slug volume. A variable-head test with trapped gas is described by three equations to be solved simultaneously. The gas pocket contraction leads to an underestimation of the hydraulic conductivity, k, especially for small pipes used to test natural or compacted clay. It must be considered, however, that the difference between the theoretical and measured changes in initial water level is due to the sum of trapped gas contraction plus cavity expansion (falling-head) or trapped gas expansion plus cavity contraction (rising head). This difference cannot be used to assess the volume of trapped gas unless an independent mechanical test has established the material deformability. For example, pressuremeter tests can be done in cavities that are prepared with the same care as those used for the installation of piezometers. A simple test that consists of adding or removing known volumes of water in the pipe of the piezometer is described. Field data are provided along with the method to handle them and extract the correct k value. To avoid gas entrapment in the filter pack, a small diameter plastic tube can be installed and used as a gas vent.
Tree species distribution and its impact on soil properties, and nitrogen and phosphorus mineralization in a humid subtropical forest ecosystem of northeastern India
Authors: Kamei Jenpuiru , Pandey H. N. , Barik S. K.
Published: January 2009

The impact of tree species on net N and P mineralization, and soil properties beneath their canopy were studied in a subtropical evergreen broad-leaved forest of northeastern India. Four types of experimental plots were identified based on tree species dominance. The first plot was dominated by Myrica esculenta Buch.-Ham. ex D. Don., the second by Rhododendron arboreum Sm., the third by Neolitsea cassia Koster., and the fourth was a mixed-species plot. Organic carbon content (3.11%) and NH4+-N concentration (11.40 μg·g–1) in the Rhododendron plot, pH (4.64) and total N content (0.89%) in the mixed plot, available P (5.16 μg·g–1) and NO3–-N (8.63 μg·g–1) concentrations in the Neolitsea plot were significantly higher (p < 0.001) than the other plots. All these soil parameters were lowest in the Myrica plot. The net N and P mineralization rates in an annual cycle across different plots ranged between 18.83 and 22.14 μg·g–1·month–1and between 4.54 and 5.87 μg·g–1·month–1, respectively. The flux varied significantly (p < 0.001) among the plots, the lowest and highest being in the Myrica plot and mixed plots, respectively. The differences in soil properties and in net N and P mineralization among different species plots were related to litter quality and yield of the respective species as well as soil microenvironment.
Growth and photosynthetic responses of two coniferous species to experimental warming and nitrogen fertilization
Authors: Zhao Chunzhang , Liu Qing
Published: January 2009

The paper studied the short-term effects of experimental warming, nitrogen fertilization, and their combination on growth and photosynthetic performances of Picea asperata Mast. and Pinus tabulaeformis Carr. seedlings. These seedlings were subjected to two levels of temperature (ambient temperature and infrared heater warming) and two nitrogen levels (0 and 25 g N·m–2·year–1) for 6 months. Warming alone and fertilization alone significantly increased biomass accumulation and photosynthetic performances of both two species. The combination of warming and fertilization stimulated greater accumulation of stem, root, and total biomass and further increased chlorophyll content and net photosynthesis rate (A) in Pinus tabulaeformis seedlings. However, for Picea asperata seedlings, the interaction induced less increment in plant height, total biomass, chlorophyll contents, A, and the efficiency of photosystem than nitrogen treatment alone. These results implied that both climate warming and nitrogen addition were favorable for the early growth of both coniferous species; the interaction of these two factors caused adding or multiplying single-factor effects in the case of Pinus tabulaeformis seedlings but dampening them in the case of Picea asperata seedlings, at least in short time.
The effect of nursery substrate and fertilization on the growth and ectomycorrhizal status of containerized and outplanted seedlings of Picea abies
Authors: Vaario Lu-Min , Tervonen Arja , Haukioja Kati , Haukioja Markku , Pennanen Taina , Timonen Sari
Published: January 2009

Over a 5 year period, we examined the influence of substrate and fertilization on nursery growth and outplanting performance of Norway spruce (Picea abies (L.) Karst.). We focused on the relative growth and development of roots and shoots and the colonization intensity and diversity of ectomycorrhizal (ECM) fungi. In the nursery, a conventional substrate (low-humified Sphagnum peat) supplemented with woody material (wood fibre and pine bark) and either mineral or organic fertilizers yielded shorter seedlings than those grown on the unmodified substrate. However, after outplanting, the growth rate of seedlings cultivated on modified substrates was higher than that of seedlings grown on the unmodified substrate. Seedlings cultivated in modified substrates had significantly higher root/shoot ratios and ECM diversity; the latter remained significant after ≥3 years of outplanting. Seedlings grown on a substrate containing 50% woody material and supplemented with organic fertilizer had the highest growth rate among all seedlings during the 3 year period of outplanting. Colonization intensity of ECM fungi was high in all seedlings except for those grown in heavily fertilized substrate. This study suggests that nursery techniques that produce seedlings with higher root/shoot ratios and ECM diversities could improve plantation success and growth rate for at least the first 3 years of outplanting.
Spatial distribution of forest landscape change in western New York from presettlement to the present
Authors: Wang Yi-Chen , Kronenfeld Barry J. , Larsen Chris P.S.
Published: January 2009

Changes in tree taxon composition and distribution in western New York over a 200 year time period ca. 1797–1993 were examined by comparing the presettlement land survey with the US Forest Inventory and Analysis (FIA) survey. To ensure data quality, biases in presettlement bearing tree selection and FIA plot location were assessed. A 6 mile × 6 mile grid of taxa abundance was then estimated using geostatistics. Overall, significant changes in taxon composition occurred, with the taxa most abundant in the presettlement land survey — beech (37.0%), sugar maple (21.0%), and eastern hemlock (8.3%) — being replaced by sugar maple (19.2%), ash (11.7%), and red maple (11.4%) in the FIA survey. Spatially resolved comparisons showed that the landscape changed from fairly spatially homogeneous to more heterogeneous; in the presettlement survey, the most abundant taxon in most of the 6 mile × 6 mile grid cells was beech, while in the present survey, the most abundant taxon in most of the cells was one of several early successional taxa that each displayed a distinctly clustered geographic pattern of dominance. The clusters of dominance of the different early successional taxa may correspond to environmental factors. This study demonstrates the insights available through spatially resolved analyses of changes in the forest landscape between presettlement and present.
Spatial dynamics of radial growth and growth efficiency in residualPinus resinosafollowing aggregated retention harvesting
Authors: Powers Matthew D. , Webster Christopher R. , Pregitzer Kurt S. , Palik Brian J.
Published: January 2009

Variable retention harvest systems are encouraged to promote complexity in managed forests, and aggregated retention has been suggested as a means of reducing moisture stress in residual trees. We studied the impacts of within-aggregate position on growth and foliar physiology to better understand the spatial dynamics of residual-tree responses to aggregated retention harvests in even-aged Pinus resinosa Ait. stands. Distance from edge and edge aspect influenced radial growth, volume increment, and growth efficiency, but only edge aspect affected foliar nitrogen content. Spatial variables had no significant relationships with foliar carbon isotope ratios (δ13C). Increases in radial growth, volume increment, and growth efficiency following harvesting were greatest near edges and in the northeastern quadrants of aggregates that received mechanical understory release treatments, and lowest in the southeastern quadrant of aggregates and near aggregate centers. Foliar nitrogen content was highest in the southwestern quadrants of aggregates that received understory release treatments, and lowest in the northwestern quadrants of aggregates. Our results suggest spatial relationships are important determinants of residual-tree responses to aggregated retention harvests.
Age-class differences in shoot photosynthesis and water relations of Fraser fir (Abies fraseri), southern Appalachian Mountains, USA
Authors: Reinhardt Keith , Johnson Daniel M. , Smith William K.
Published: January 2009

Fraser fir ( Abies fraseri (Pursh) Poir.) is an endemic tree species found only in refugial mountain-top forests in the southern Appalachian Mountains, USA. Very few studies have investigated the ecophysiology of this species in its natural environment. We measured and compared photosynthetic gas exchange and water relations of understory germinant seedlings (<3 cm height), older seedlings (>3 years old and ~0.15–1 m tall), and saplings (>10 years old and ~1–2 m tall) on a leaf-level basis. No significant differences in gas exchange were found among the age classes, although midday xylem water potentials were significantly different among the age classes. Differences in maximum photosynthesis (Amax) were <13%, ranging between 2.4 and 2.7 μmol·m–2·s–1 (P = 0.26). Maximum leaf conductances (gmax) were between 0.16 and 0.18 mol·m–2·s–1, varying less than 13% (P = 0.15). Midday xylem water potentials were similar between SE and SA (–1.2 to –1.4 MPa), but GS values were significantly less negative (–0.2 to –0.5 MPa). Thus, gas exchange and water relations in these understory age classes appeared similar, indicating no particular limitation to advanced regeneration between age classes.
A bioeconomic approach to assess the impact of an alien invasive insect on timber supply and harvesting: a case study with Sirex noctilio in eastern Canada
Authors: Yemshanov Denys , McKenney Daniel W. , de Groot Peter , Haugen Dennis , Sidders Derek , Joss Brent
Published: January 2009

This study presents a model that assesses the potential impact of a new alien insect species, Sirex noctilio Fabricius, on pine timber supply and harvest activities in eastern Canada. We integrate the spread of S. noctilio with a broad-scale growth and harvest allocation model. Projections of pine mortality range between 25 × 106 and 115 × 106 m3 over 20 years depending on S. noctilio spread and impact assumptions. Our model suggests Ontario could experience the highest, most immediate losses (78% of the potential losses across eastern Canada), with Quebec sustaining most of the rest of the losses over the next 20 years. Potential losses of $86 to $254 million per year are simulated after 20 years. The net present value of total harvest losses after 28 years of outbreak ranges between $0.7 to $2.1 billion. Adaptation policies decrease short-term losses by 46%–55% and delay larger harvest failures by 9–11 years. Without harvest adaptation, failures to maintain annual allowable cut levels may occur once the total area infested exceeds 15 × 106 ha. While better understanding and representing S. noctilio behaviour will involve a significant effort, there is a strong demand by policy makers for this kind of information.
Compatible diameter and height increment models for lodgepole pine, trembling aspen, and white spruce
Authors: Nunifu Thompson K.
Published: January 2009

In this study, compatible height and diameter increment models were fitted for lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.), trembling aspen ( Populus tremuloides Michx.), and white spruce ( Picea glauca (Moench) Voss), using the relationship between diameter and height growth. It was assumed that tree diameter increment is directly proportional to height increment, and the proportionality constant is a function of competition and site productivity. The results showed that the fit statistics are comparable with results of other studies, with adjusted R2ranging from 30% to 50%. A validation test of the models, using independent permanent sample plots data, showed that the short-term predictions of the models for both pure and mixedwood stands are fairly unbiased. The models also gave reasonable average height growth and diameter growth trajectories for pure stands of the three species and also projected long-term mixedwood (aspen – white spruce mixture) volume growth dynamics reasonably well. The models also projected reasonably well (i) the effect of increasing initial stem density on average diameter and height, and (ii) the stand volume compared with an older version the Mixedwood Growth Model (ver. 2000A). It was concluded that explicitly linking tree height and diameter increment models does not only have a solid ecological basis, but it also results in a compatible prediction of tree growth and stand dynamics.
THREE-BODY FORCE MODELS OF NONHYPERCENTRAL HARMONIC AND ANHARMONIC POTENTIALS IN THREE-DIMENSIONAL POTENTIALS
Authors: SHOJAEI M. R. , RAJABI A. A.
Published: January 2009

We present a theoretical approach to the internal motion of a system based on three-body forces among particles in a special case, using three-body potentials. The three-body force models are more easily introduced and treated within the hyperspherical harmonic formalism. The internal particle motion is usually described by means of the Jacobian relative coordinates ρ, λ and R. The problems related to three-body nonhypercentral potentials in three dimensions are investigated. While the difficulties that arise in the study of nonhypercentral potentials are explicitly shown, we discuss some results obtained using nonhypercentral harmonic and anharmonic and some inverse power terms; however the potential can be easily generalized in order to allow a systematic analysis, which presents an exact solution to the wave function. The method is also applied to some other types of potentials.
CHIRAL CONDENSATE IN NUCLEAR MATTER WITH VACUUM CORRECTIONS
Authors: JIANG WEI-ZHOU , LI BAO-AN
Published: January 2009

Within the relativistic Hartree approach using a Lagrangian with density-dependent parameters according to the Brown–Rho scaling law, it is found that the vacuum corrections from the nucleon Dirac sea soften the equation of state and favor the chiral symmetry restoration at high densities.
SINGLE-HIT CRITERION IN DAMA/LIBRA DM SEARCH AND DAEMONS — THEY ARE ANYTHING BUT WEAKLY INTERACTING
Authors: DROBYSHEVSKI E. M.
Published: January 2009

Our prediction that the more massive DAMA/LIBRA detector would detect a smaller number of events per unit of mass and time than the DAMA/NaI system has got confirmation. It is easy to understand, because DM objects are by far not the WIMPs of the Galactic halo that interact only weakly with matter but are apparently electrically charged Planckian objects, i.e. daemons which fall from Earth-crossing orbits with V = 30–50 km/s and undergo multiple interaction with condensed matter already in its outer layers, on a path of a few tens of cm. Therefore, one should use not compact massive detectors but rather systems with a large surface area, as we did to detect daemons with thin ZnS ( Ag ) scintillators. There are grounds to believe that correct use of the single-hit criterion in LIBRA should reveal DM particles with V = 30–50 km/s, and subsequently, with V = 10–15 km/s as well.
HAWKING TEMPERATURE OF DILATON BLACK HOLES FROM TUNNELING
Authors: REN JI-RONG , LI RAN , LIU FEI-HU
Published: January 2009

Recently, it has been suggested that Hawking radiation can be derived from quantum tunneling methods. Here, we calculated Hawking temperature of dilatonic black holes from tunneling formalism. The two semiclassical methods adopted here are: the null-geodesic method proposed by Parikh and Wilczek and the Hamilton–Jacobi method proposed by Angheben et al. We apply the two methods to analyze the Hawking temperature of the static spherical symmetric dilatonic black hole, the rotating Kaluza–Klein black hole, and the rotating Kerr–Sen black hole.
ON SIX-DIMENSIONAL FUNDAMENTAL SUPERSTRINGS AS HOLOGRAMS
Authors: ALISHAHIHA MOHSEN , MUKHOPADHYAY SUBIR
Published: January 2009

In this paper we discuss a possible holographic dual of the two-dimensional conformal field theory associated with the world-sheet of a macroscopic superstring in a compactification on a four-torus. We assume that the near-horizon geometry of the black string has symmetries of AdS 3×S3×T4 and construct a sigma model in the bulk. Analyzing the symmetries of the bulk theory and comparing them with those of the CFT in a special light-cone gauge, we find agreement between global symmetries. Due to nonstandard gauge realization it is not clear how affine symmetries can be realized.
NEW ANGLE ON THE STRONG CP AND CHIRAL SYMMETRY PROBLEMS FROM A ROTATING MASS MATRIX
Authors: BORDES JOSÉ , CHAN HONG-MO , TSUN TSOU SHEUNG
Published: January 2009

It is shown that when the mass matrix changes in orientation (i.e. rotates) in generation space for a changing energy scale, the masses of the lower generations are not given just by its eigenvalues. In particular, these masses need not be zero even when the eigenvalues are zero. In that case, the strong CP problem can be avoided by removing the unwanted θ term by a chiral transformation not in contradiction with the nonvanishing quark masses experimentally observed. Similarly, a rotating mass matrix may shed new light on the problem of chiral symmetry breaking. That the fermion mass matrix may so rotate with the scale has been suggested before as a possible explanation for up–down fermion mixing and fermion mass hierarchy, giving results in good agreement with experiment.
α-SYMMETRIES, COLORED DIMENSIONS AND GAUGE–STRING CORRESPONDENCE
Authors: POLYAKOV DIMITRI
Published: January 2009

We propose a scenario of gauge–string correspondence by relating the SU(3) color group to hidden space–time isometries originating from extra dimensions. These isometries (α-symmetries) are the special symmetries of RNS superstring theories under global nonlinear space–time transformations. The vertex operators for the octet of gluons are constructed by the procedure of "photon painting," that is, with the SU(3) subgroup of the α-symmetry generators acting on a regular open string photon, so the corresponding open string excitations are in the adjoint of SU(3). Remarkably, the operator algebra of these massless gluon vertices is closed and possesses the full zigzag symmetry, crucial for the isomorphism between open strings and QCD. As a result, the scattering amplitudes of the constructed open string vertex operators have a field-theoretic rather than a stringy structure, including the absence of standard tower of massive intermediate states. Our model also suggests that the total number of underlying hidden dimensions is three, with each extra dimension carrying its appropriate SU(3) color and anticolor.
MASSIVE GRAVITY IN CURVED COSMOLOGICAL BACKGROUNDS
Authors: MAENO MASAHIRO , ODA ICHIRO
Published: January 2009

We study the physical propagating modes in a massive gravity model in curved cosmological backgrounds, which we have found as classical solutions in our previous paper. We show that, generically, there exist such the cosmological background solutions consistent with the equations of motion where we assume the ghost condensation ansatzes. Using the (1 + 3)-parametrization of the metric fluctuations with "unitary" gauge, we find that there is neither a scalar ghost nor a tachyon in the spectrum of the propagating modes, the tensor modes become massive owing to gravitational Higgs mechanism, and the model is free of the Boulware–Deser instability. The price we have to pay is that the scalar sector breaks the Lorentz-invariance, but there are no pathologies in the spectrum and lead to interesting phenomenology. Moreover, we present a proof of the absence of nonunitary modes for a specific ghost condensation model in a cosmological background.
MICROSTRIP ELECTROMAGNETIC BANDGAP ELEMENT ON GROUND FOR HYBRID RING COUPLERS
Authors: ZHANG FEI , LI CHENGFANG
Published: January 2009

In this paper, a novel compact rat-race hybrid coupler incorporating square open-loop defected ground structures (SOL-DGSs) is designed and verified. As a new wave of microstrip electromagnetic bandgap element (MEBE) technology on ground plane, the bandgap characteristic of SOL-DGS is employed to reject the high-order harmonics without any additional filter and the excellent slow-wave effect of SOL-DGS is studied and utilized to reduce the circuit size in the design of the hybrid coupler. The measured insertion losses are 3.54 dB and 3.63 dB for two input ports. The isolation between port 1 and port 3 achieves around -30 dB. Furthermore, the proposed rat-race coupler successfully rejects the second, third, fourth and even fifth harmonic signals.
QUANTUM PHASES OF ULTRACOLD BOSONIC ATOMS IN A TWO-DIMENSIONAL OPTICAL SUPERLATTICE
Authors: HOU JING-MIN
Published: January 2009

We study quantum phases of ultracold bosonic atoms in a two-dimensional optical superlattice. The extended Bose–Hubbard model derived from the system of ultracold bosonic atoms in an optical superlattice is solved numerically with the Gutzwiller approach. We find that the modulated superfluid (MS), Mott-insulator (MI) and density-wave (DW) phases appear in some regimes of parameters. The experimental detection of the first-order correlations and the second-order correlations of different quantum phases with time-of-flight and noise-correlation techniques is proposed.
DYNAMICS OF CATHODE SPOT MOVEMENT ON A CARBON/CARBON COMPOSITE IN VACUUM
Authors: ZHANG CHENGYU , QIAO SHENGRU , YANG ZHIMAO , GUO YONG
Published: January 2009

The dynamics of cathode spot movements on a three-dimensional carbon fiber reinforced carbon/carbon composite were investigated by a scanning electron microscope and a digital high-speed video camera. The results show that the motion direction of the cathode spots is parallel to the carbon fibers. The directed motion of the cathode spots is accompanied by the cycle of alternative splitting and extinguishment of cathode spots. The group of the cathode spots can split into two small groups when it moves far away from the ignition site. Within 40 μs, the two small groups completely depart each other. The splitting of the cathode spots group is caused by the current degradation. The former group continues to go forward, and the latter extinguishes within 40 μs. The transient and the average velocity of the "lead" spot are estimated to be 0.9–3.4 m/s and ~ 2.11 m/s, respectively. The diffusion constant of the cathode spot is (9.11±0.59) ×10-5 m2/s.
A PROTOCOL FOR MAKING AN AGREEMENT IN A PEER-TO-PEER (P2P) SOCIETY
Authors: AIKEBAIER AILIXIER , BAROLLI VALBONA , ENOKIDO TOMOYA , TAKIZAWA MAKOTO
Published: January 2009

There are many discussions on agreement protocols of multiple peer processes (peers) where every peer just aims at agreeing on one value out of values shown by the peers. In meetings of human societies, agreement procedures are so flexible that persons can change their opinions and can use not only all-condition where every person agrees on one value but also various types of agreement conditions like majority-condition. In this paper, we discuss a flexible agreement protocol of multiple peers by taking into account human behaviors in social agreement procedures. Each peer first takes a value v1 and notifies the other peers of the value v1. A peer pi in turn receives values from other peers. Unless a set of the values from all the peers satisfy the agreement condition, the peer pi can take another value v2. In order to model the social human behavior, in our previous work we discussed E - and P -precedent relations [Formula: see text] and [Formula: see text] on values of a peer pi. The relations [Formula: see text] and [Formula: see text] show that a peer pi can take a value v2 after taking a value v1 and prefers v1 to v2, respectively. If a peer autonomously takes values based on its precedent relations, the peers might not make an agreement even if there exists a satisfiable set of previous values. We discuss what previous values the peer can take again. In this paper, we try to find a satisfiable set of previous values in a history of values which the peers have so far taken, in addition for each peer to taking a new value at each round.
A NOVEL SPECTRUM OF EPOCH CONVERGENT CONGESTION CONTROL
Authors: QU YANSHENG , LUO JUNZHOU , WANG PENG , YANG LAURENCE T.
Published: January 2009

Achieving efficient and fairness bandwidth allocations among connections in high bandwidth delay product networks has been a daunting challenge. Addressing the deficiency of previous protocols, this paper presents a novel spectrum of Epoch Convergent Congestion Control protocols for deployment in high speed and long distance networks. Most of the end to end high speed protocols that has been presented can be seen as a member of ECCC. Through extensive analysis of ECCC, we focus on SQUARE, one of the protocols in Epoch Convergent Congestion Control. Without the need to revise the current end-to-end architecture, SQUARE is shown to be efficient when there is bandwidth available, to be fair when many flows compete with each other for the same bottleneck, to be friendly when deployed with the conventional TCP, to be robust when there are oscillations in the network.
INCREMENTAL K-NEAREST-NEIGHBOR SEARCH ON ROAD NETWORKS
Authors: ZHAO GENG , XUAN KEFENG , TANIAR DAVID , SRINIVASAN BALA
Published: January 2009

Most query search on road networks is either to find objects within a certain range (range search) or to find K nearest neighbors (KNN) on the actual road network map. In this paper, we propose a novel query, that is, incremental k nearest neighbor (iKNN). iKNN can be defined as given a set of candidate interest objects, a query point and the number of objects k, find a path which starts at the query point, goes through k interest objects and the distance of this path is the shortest among all possible paths. This is a new type of query, which can be used when we want to visit k interest objects one by one from the query point. This approach is based on expanding the network from the query point, keeping the results in a query set and updating the query set when reaching network intersection or interest objects. The basic theory of this approach is Dijkstra's algorithm and the Incremental Network Expansion (INE) algorithm. Our experiment verified the applicability of the proposed approach to solve the queries, which involve finding incremental k nearest neighbor.
AVERAGE-CASE "MESSY" BROADCASTING
Authors: LI CHENKUAN , HART THOMAS E. , HENRY KEVIN J. , NEUFELD IAN A.
Published: January 2009

Current studies of "messy" broadcasting have so far concentrated on finding worst-case times. However, such worst-case scenarios are extremely unlikely to occur in general. Hence, determining average-case times or tight upper bounds for completing "messy" broadcasting in various network topologies is both necessary and meaningful in practice. In this paper, we focus on seeking the average-case "messy" broadcast times of stars, paths, cycles, and d-ary trees, and finding good upper bounds for hypercubes. Finally, we derive a recursive formula to express the average-case time for a specific "messy" broadcast model on a complete graph using a classical occupancy problem in probability theory, and provide a nice simulation result which indicates that this model behaves like classical broadcasting.