bluuebunny/crossref_metadata_2025 huggingface dataset:
A Doppler radar for continuous remote measurement of river ice velocity
Authors: Ferrick M. G. , Yankielun N. E. , Nelson D. F.
Published: January 2010

River ice velocity measurements are fundamental to analyses of river ice dynamics. Ice velocity measurement with a continuous-wave Doppler radar system having real-time data acquisition and digital signal processing capability was evaluated during a river breakup and a frazil run on the Connecticut River. This system can be rapidly deployed, requires minimal operator interaction, will continuously acquire, process, store, and display ice velocity data, and does not depend on visibility conditions. In parallel, video records of ice motion were obtained at the same location for later manual processing and comparison with the radar results. We describe the Doppler radar system and obtain bounding estimates of possible measurement errors. The principal error in Doppler ice velocity measurement is due to the beam width of the radar antenna, and an analytical method is developed to minimize this error. Measured ice velocities ranged from 1 to 2.5 m/s during the river breakup, and from 0.5 to 0.65 m/s in the frazil run. Quantitative comparisons between the radar and video results show fundamental agreement between these measurement methods, and demonstrate that Doppler radar is an effective, efficient, and precise tool for obtaining river ice velocities over the full range of possible ice and velocity conditions. Key words: Doppler radar, river ice velocity, velocity measurement, error analysis, river breakup, frazil run.
Design rated oriented strandboard in CSA standards
Authors: Karacabeyli Erol , Lau Peter , Deacon William , Henderson C. R. , Meakes F. V.
Published: January 2010

The 1994 edition of CSA (Canadian Standards Association) Standard 086.1 "Engineering design in wood" includes, for the first time, specified strength and stiffness for design rated oriented strandboard (OSB). Design rated OSB panels are manufactured in accordance with the new CSA Standard 0452. In this paper, the results of the short-term (1–10 min) test data which led to the establishment of the three rating grades of Type 1 (standard) design rated OSB are presented. In addition, factors that may affect the classification such as panel thickness and orientation are discussed. Key words: OSB, waferboard, structural panels, wood.
Low temperature behaviour of CFRP prestressed concrete beams
Authors: Bryan Paul E. , Green Mark F.
Published: January 2010

The corrosion of steel prestressing tendons exposed to deicing salts is increasingly becoming a significant problem in Canada. New fibre reinforced plastic (FRP) materials with high strength-to-weight ratios and noncorrosive characteristics are strong alternatives to solve this problem. Carbon fibre reinforced plastic (CFRP) is one of the most promising among available FRPs. Nevertheless, for CFRP rods to gain acceptance in Canada and other cold regions, their behaviour at low temperatures must be investigated. This paper describes an investigation of the feasibility of using CFRP LEADLINE rods to prestress concrete beams. The results of an experimental program on the short-term behaviour of CFRP prestressed concrete beams at low temperature (−27 °C) are discussed. A simple analytical model is used to predict the flexural response of CFRP beams at low temperature. The experimental results agree well with the analytical predictions. The behaviour of the CFRP tendons is shown to be unaffected by short-term exposure to this low temperature. Key words: carbon fibre, fibre reinforced plastic (FRP), advanced composite materials, prestressed concrete, low temperature, cold regions.
Digital image processing for aggregate orientation in asphalt concrete mixtures
Authors: Yue Zhong Qi , Morin Isabelle
Published: January 2010

Asphalt concrete is a composite material which consists of asphalt cement, voids, fine particles, sand, and coarse aggregates. Previous investigations of asphalt concrete mixtures have mainly concentrated on the macroscopic properties of the composite materials based on the assumption that the mixtures are homogeneous and isotropic. This paper applies an innovative digital image processing technique to quantify the orientations of coarse aggregate particles (≥ 2 mm) in asphalt concrete mixtures such as hot mix asphalt, stone matrix asphalt, and large stone asphalt compacted in the laboratory or field. The results indicate quantitatively that asphalt concrete specimens compacted in the field or in the laboratory with gyratory compactor have an oriented structure of aggregate particle distribution where the major cross sections of aggregate particles have the tendency to lie horizontally, and that aggregate particles are more randomly oriented in the asphalt concrete specimens compacted in the laboratory with the Marshall compactor. Key words: asphalt concrete mixtures, digital image processing, microstructure, aggregate orientation, anisotropy, compaction methods.
Stressed log bridges
Authors: Bakht Baidar , Maheu John , Bolshakova Tatiana
Published: January 2010

The stressed log bridge was conceived as a means of recycling discarded utility timber poles, or logs, which are difficult to dispose because of having been treated with preservatives. To minimize wastage, the logs are trimmed to obtain two parallel flat surfaces, against which they are stacked and laterally stressed as in the familiar stress laminated wood decks. The log decks introduced in this paper are recommended to be stressed by means of aramid or glass fibre tendons which are inert and extremely flexible; because of which, the prestress losses can be virtually eliminated. The paper presents the details of the design, construction, and testing of a prototype stressed log bridge built to demonstrate the concept. The bridge was post-tensioned with aramid fibre cables known by the trade name of PARAFIL ropes. The tendons were first stressed to the maximum level corresponding to a high pressure that can be sustained by the wood and then, within half an hour, destressed to about 68% of the initial force. Observations over a period of about 10 months have confirmed that restressing of the deck is not required. Mainly because of economy, the use of glass fibre reinforced plastic rods is recommended instead of the aramid fibre cables. Key words: aramid fibre, bridge, glass fibre, log, prestress losses, stress laminated wood deck, timber bridge.
A conservative diffusion wave flood routing scheme for channel networks
Authors: Sabur M. A. , Steffler P. M.
Published: January 2010

For long flood waves propagating over considerable distances on relatively flat slopes, the diffusion wave is an adequate approximation to the St. Venant equations of unsteady channel flow. A relatively simple and robust computational scheme based on this approximation is presented herein. The scheme is based on mass conservation equations for discrete control volumes with unique intervolume flows which ensures overall mass conservation. Simple guidelines for determining the spatial and temporal discretizations are provided. Application to a number of test situations indicates that the scheme offers acceptable accuracy without calibration using only reach-averaged channel geometry and roughness characteristics. The scheme would be especially useful as a subcomponent of a large-scale distributed hydrologic or water resources system model. Key words: flood routing, rivers, channels, networks, computational hydraulics, diffusive wave, hydrologic modelling, St. Venant equations.
Effect of government policies and vehicle marketing strategies on household vehicle demand and fuel consumption
Authors: Hamed Mohammad M. , Abdelwahab Walid M.
Published: January 2010

The objective of this paper is to develop demand models to forecast household vehicle demand and corresponding fuel consumption in Jordan. Understanding the factors that influence household vehicle quantity holdings provides a useful tool for developing strategies aimed at curtailing the contribution of automobiles towards environmental pollution, traffic congestion, and traffic accidents in urban areas. The demand for automobile and fuel by a household is simultaneously estimated by a joint discrete and continuous choice model. A multinomial logit model is used to examine the number of vehicles owned by a household, whereas a multiple regression model is used to predict the amount of fuel consumed. A random sample of households from the Greater Amman area is used to estimate demand and choice models. Results suggest that the socioeconomic characteristics of a household, government policies relating to vehicle import duties and vintage, and private sector marketing strategies, all influence a household's decision on the number of vehicles owned. Results strongly show that households with different vehicle ownership levels respond differently to government policies and car dealers' marketing strategies. Policy makers and transportation planners can use the results of this study to forecast the expected demand for used cars, and the increase in the number of new cars, given a set of government and private sector strategies. The results also can be used to predict fuel demand at various levels of household vehicle ownership. Transportation planners can also use these results to assist in formulating strategies regarding urban road network improvements, and future demand for public transportation. Key words: vehicle ownership, fuel consumption, logit model, government policy.
Influence de la température minimale du cycle de gel–dégel sur la détérioration du béton par écaillage en présence de sels fondants
Authors: Marchand J. , Pigeon M. , Boisvert L.
Published: January 2010

Eight different concrete mixtures were prepared to investigate the influence of the minimum temperature of the freezing and thawing cycle on scaling deterioration due to deicer salt. In addition to the two minimum temperatures studied (−18 and −9 °C), test variables included the type of binder (with or without silica fume), the water/binder ratio (0.35 or 0.45), the characteristics of the air-void network (with or without air entrainment), and the drying temperature during the conditioning period prior to the scaling test (20, 40, or 110 °C). The scaling resistance to deicer salt of all concrete mixtures was assessed according to the prescriptions of the ASTM C672 test procedure using a 3 % NaCl solution. Test results indicate that a reduction of the minimal temperature from −9 to −18 °C significantly increases the scaling deterioration of concrete due to deicer salt. Key words: freezing cycle, scaling resistance, minimal freezing temperature, deicer salts.
L'optimisation de la résistance à court terme des bétons fabriqués avec un ciment de type 20M
Authors: Kessal Mustapha , Edwards-Lajnef Mona , Tagnit-Hamou Arezki , Aïtcin Pierre-Claude
Published: January 2010

This study shows that it is possible to make a concrete with high early strength when using a type 20M cement having a low heat of hydration, as used by Hydro-Québec in hydroelectric structures. Such a concrete allows the forms to be removed rapidly while developing a minimum heat of hydration. This property is due to a low water/binder ratio and is obtained by specific dosage of additives such as a superplasticizer, a silica fume, and a fine limestone filler. Substitution of 20% of the cement by silica fume and limestone filler did not alter the development of the compressive strength compared to a normal strength concrete presently in use. A factorial design has allowed to optimize, after a limited number of trials, the mix design for resistance in young concrete made with type 20M cement. Key words: short term strength, high performance concrete, superplasticizer, silica fume, limestone filler, low heat of hydration, mass concrete, cement additives, curing temperature, factorial design.
Girder moments in simply supported skew composite bridges
Authors: Ebeido Tarek , Kennedy John B.
Published: January 2010

The evaluation of girder moments in composite bridges becomes more urgent with the trend to increasing truck loads. The method specified by the American Association of State Highway and Transportation Officials for such an evaluation depends only on the centre-to-centre girder spacing. This method does not account for skew and therefore is extremely conservative for skew composite bridges, since the presence of skew reduces the longitudinal moments in the girders. The method proposed by the Ontario Highway Bridge Design Code (OHBDC) depends on the longitudinal and transverse rigidities of the bridge in addition to the girder spacing. However, this method is limited to bridges with skew parameters less than a certain value specified in the code. In this paper, the influence of skew on the moment distribution factor is investigated. Furthermore, the influences of other factors such as girder spacing, bridge aspect ratio, number of lanes, number of girders, and intermediate transverse diaphragms on the moment distribution factor are examined. An experimental program was conducted on six simply supported skew composite steel–concrete bridge models. The finite element method was used for the theoretical analysis. Good agreement is shown between the experimental results and the theoretical results. In addition, the finite element method was employed to conduct an extensive parametric study on more than 300 prototype composite bridge cases. The data generated from the parametric study were used to deduce expressions for the moment distribution factor for OHBDC truck loading and for dead load. An illustrative example is presented. Key words: bridges, codes of practice, composite, distribution, moment, reinforced concrete, skew, structural engineering, tests.
Construction resource leveling using neural networks
Authors: Savin Daniela , Alkass Sabah , Fazio Paul
Published: January 2010

A neural network model for construction resource leveling is developed and discussed. The model is derived by mapping an augmented Lagrangian multiplier optimization formulation of a resource leveling problem onto a discrete-time Hopfield net. The resulting neural network model consists of two main blocks. Specifically, it consists of a discrete-time Hopfield neural network block, and a control block for the adjustment of Lagrange multipliers in the augmented Lagrangian multiplier optimization, and for the computation of the new set of weights of the neural network block. An experimental verification of the proposed artificial neural network model is also provided. Key words: neural networks in construction, resource leveling, construction management, project management.
Effect of end distance on the resistance of spilt ring and shear plate connectors loaded perpendicular to grain
Authors: Quenneville J. H. P. , Charron J. G. A.
Published: January 2010

An experimental study was undertaken to verify the end distance requirements in the CSA Standard O86.1-94 "Engineering design in wood (limit states design)" for split ring and shear plate connectors in joints loaded perpendicular to grain. In a laboratory study, 48 joints of the Douglas fir – larch species group were loaded to failure perpendicular to grain. Twenty-eight of those joints were tested using 102 mm diameter shear plates, and the remaining 20 joints were tested using 63 mm diameter split rings. Of the 28 joints tested with 102 mm shear plates, 16 of the specimens were made of laminated Douglas fir and the other 12 specimens were made of sawn lumber Douglas fir. End distances of 80, 130, 140, and 180 mm were studied for each of the two shear plate tests. Specimens using 63 mm split rings were tested at end distances of 80 and 140 mm. Results show that when using 102 mm shear plate and 63 mm split ring connectors, the end distance of the connector has no statistically significant effect on the resistance of the connector. Changes to the Canadian wood design standard are recommended. Key words: wood, fasteners, resistance, split ring, shear plate, end distance.
Drift-based methodology for seismic proportioning of coupled shear walls
Authors: Chaallal O. , Guizani L. , Malenfant P.
Published: January 2010

This paper presents a design tool for size proportioning of reinforced concrete coupled shear walls built in seismic regions. It is based on the maximum allowable drift that can be selected by the designer. Free vibration and modal analyses are performed on a variety of coupled shear walls of different heights and geometries. From these analyses, fundamental periods are first related to geometric properties of coupled shear walls and then to maximum interstorey drifts. These maximum drifts are obtained from both spectrum analysis and pseudo-static approach. Closed-form formulas for estimating the required fundamental periods of coupled wall systems as a function of maximum allowable drift are derived. The design of the wall system can be based on geometric dimensions to yield the stiffness to achieve the required period. These formulas not only are thought to be useful for preliminary size proportioning, but also can constitute an advantageous starting point for more sophisticated analyses. To demonstrate the applicability of these formulas and to clarify design issues, a design example is treated and results are compared with static and dynamic analyses. Key words: coupled shear wall, reinforced concrete, ductility, force modification factor, interstorey drift, fundamental period, seismic.
Thermal impact of artificial circulation on an ice-covered mid-latitude lake
Authors: Rogers Christopher K. , Lawrence Gregory A. , Hamblin Paul F.
Published: January 2010

We measured the impact of an artificial circulation device designed to maintain a polynya in an otherwise ice-covered lake. Field observations revealed that the presence of the polynya causes a substantial reduction in average lake temperature when compared with a nearby lake left in its natural state. We extended a numerical model of the heat budget of a small ice-covered lake to incorporate the effects of the artificial circulation device. The model showed that during the cooling period the average heat lost from turbulent heat transfer between water and ice was three times that lost across the polynya surface. Lake temperature, polynya size, and snow depth were well represented by the model; however, there were discrepancies between early winter ice thickness predictions and observations. Key words: polynya, artificial circulation, radial jet, ice-covered lake, heat budget, numerical simulation.
Robust simple scaling analysis of flood peaks series
Authors: Ribeiro Joseph , Rousselle Jean
Published: January 2010

Simple scaling theory explains the spatial variability of peak flow processes by their indexation on a set of scale parameters, such as the size of drainage basins. On this basis, a regional analysis can be conducted to construct a unique growth curve. However, a drawback of the simple scaling approach is that it assumes that the coefficients of variation of peak flow distributions are identical throughout a region. Although empirical data might display statistical properties which correspond to simple scaling assumptions, the coefficient of variation of flood peaks depends on drainage area. We discuss this fact here and we suggest using the empirical Bayes method to take into account this regional variation of the coefficient of variation. The advantage of using an empirical Bayes analysis subsequent to simple scaling modeling is illustrated using a set of 109 flood series from the Province of Ontario, Canada. Key words: simple scaling, empirical Bayes, index flood, regional flood frequency analysis.
Cracking behaviour of concrete beams reinforced with fiber reinforced plastic rebars
Authors: Masmoudi R. , Benmokrane B. , Chaallal O.
Published: January 2010

This paper presents the results of an experimental investigation on the cracking behaviour of concrete beams reinforced with fiber reinforced plastic rebars. The effects of reinforcement ratio on the cracking pattern, crack spacing, cracking moment, and crack width are investigated. The test results indicate that the reinforcement ratio has no meaningful effect on the cracking moment, which can be calculated as recommended by the ACI code. Also, the use of the equations adopted by ACI and the European codes for the prediction of crack width of conventionally reinforced concrete members is investigated and due modifications are made. Both relationships show good correlation with the test results; and the prediction of crack width of concrete beams reinforced with these two types of fiber reinforced plastic rebars is now possible. Key words: beam, cracking behaviour, cracking moment, crack width, fiber reinforced plastic, flexure, rebars, reinforced concrete, reinforcement ratio.
Free-surface flows with near-critical flow conditions
Authors: Chanson H.
Published: January 2010

Open channel flow situations with near-critical flow conditions are often characterized by the development of free-surface instabilities (i.e., undulations). The paper develops a review of several near-critical flow situations. Experimental results are compared with ideal-fluid flow calculations. The analysis is completed by a series of new experiments. The results indicate that, for Froude numbers slightly above unity, the free-surface characteristics are very similar. However, with increasing Froude numbers, distinctive flow patterns develop. Key words: open channel flow, critical flow conditions, free-surface undulations, flow instability, undular surge, undular broad-crested weir flow, culvert flow.
Dissipation of intense vortices
Authors: Aboelkassem Yasser
Published: January 2010

In this article, we extend the space-time analogy shared by viscous vortices to generalize the dissipation of intense vortices Vatistas and Aboelkassem (Am. Inst. Aeronaut. Astronaut. J. 44, 912 (2006)). The main objective is to layout a mathematical algorithm that can be used to transform vortices into their dissipative phase or into a steady-state counterpart via a similarity transformation to Navier–Stokes equations. The method is applied to examine the time decay of eddies that belong to the Oseen-like concentrated type of viscous vortices. The steady-state Burgers’ vortex model was used to validate the transformation approach. This analysis shows that, upon variable transformation, Burgers’ vortex model has changed into the Oseen–Lamb class of decaying vortices. The approach is simple, general, and applicable to all kinds of viscous incompressible vortices like those of Sullivan, Rott, Bellamy-Knights, Vatistas, and Scully.
Magnetic resonance spectroscopy of extra-terrestrial methyl radical
Authors: Weil J. A. , Howarth D. F.
Published: January 2010

The particular molecule discussed in some detail herein is the methyl radical, CH3, with emphasis on its potential extraterrestrial appearance. In earlier papers, including group-theoretical analysis, it was shown that the isotropic EPR spectra of free radical (S = 1/2) species XLn, where the n equivalent nuclei also have spin 1/2, have a more complicated form than disclosed by the usual (first-order) oversimplified analysis. In the present work, we focus on the magnetic resonance of such systems at or near zero external magnetic field, and on the spectra obtained both by perpendicular [Formula: see text] and parallel-field [Formula: see text] excitation. This work summarizes what is known about the spin-flip transitions of CH3, and predicts what likely will be observed (0–200 MHz, under various field and scan conditions), for the future use by astrophysicists.
Some electron probe X-ray microanalysis (EPMA)- and (BPES)-related physical investigations on ZnSSe thin-films growth composition-related kinetics
Authors: Fridjine S. , Boubaker K. , Amlouk M.
Published: January 2010

In this study, ZnSSe epilayers were grown on (111) ZnS sprayed thin films. The spectral analysis was carried out in the region from 400 to 1800 nm. Analyses of the transmittance and (or) reflectance spectra indicate a decrease of the band gap energy value Eg with selenization. As the selenization process changes the structure and property of prepared materials and therefore has a direct effect on their physical properties, one of the concerns of this paper is to investigate the depth-dependent composition changes as guides to monitoring the selenization kinetics. Photothermal, atomic force microscopy (AFM), and X-ray diffraction (XRD) investigations have also been carried out.
Target finding time for microtubules in a confined geometry
Authors: Feizabadi Mitra Shojania
Published: January 2010

Dynamic instability of microtubules may reach the steady state with exponentially growing or decaying length distribution in a confined geometry such as a cell-like environment. In this brief communication, the target finding time for these microtubules with the stochastic polymerization in a confined geometry is compared with the reversible polymerization. It is shown that the efficiency of microtubules with increasing length distribution at the steady state depends on the location of a target. They are very efficient in finding a target located at the cell cortex, which confirms the significant biological role they play in rapidly reaching the cell cortex to change the cell shape and to coordinate a motile activity around the cell periphery.
A boroxol ring doped zigzag boron nitride nanotube: a computational DFT study of the quadrupole coupling constant
Authors: Boshra Asadollah , Seif Ahmad
Published: January 2010

Based upon density functional theory, we investigate the influence of oxygen dopant atoms that make a boroxol ring on the electrostatic properties of a zigzag (10, 0) boron nitride nanotube in which three of the nitrogen atoms are replaced by oxygen dopant atoms. The electric field gradient (EFG) tensors at the sites of 11B and 14N nuclei were calculated and converted to quadrupole coupling constants (CQ) in the two models of a perfect and a boroxol ring O-doped (10, 0) single-walled boron nitride nanotube (BNNT). Our calculations showed that the CQ values of the boron and nitrogen nuclei along the length of a perfect BNNT are divided into layers. Among the layers the mouth layers have the largest CQ magnitudes. In the doped model, in addition to the mouth layers, the CQ values of those nitrogen nuclei which directly bond to the boroxol ring are increased. However, the CQ values of the boron nuclei that make the boroxol ring and directly bond to the boroxol ring are decreased.
The Parallelometer: a mechanical device to study curvature
Authors: Rojo Alberto G. , Garfinkle David
Published: January 2010

A simple mechanical device is introduced, the parallelometer, that can be used to measure the curvatures of surfaces. The device can be used as a practical illustration of parallel transport of a vector. Its connection to the Foucault pendulum is discussed.
An atom chip for the manipulation of ultracold atoms
Authors: Cherry O. , Carter J. D. , Martin J. D.D.
Published: January 2010

We have fabricated an atom chip that magnetically traps laser cooled 87Rb by generating high magnetic-field gradients using micrometre scale current-carrying wires. The wires are fabricated on a Si wafer (with a 40 nm SiO2 layer) using 1.2 μm thick Au and a 20 nm thick adhesion layer, and are patterned with lift-off photolithography. We characterize the number and temperature of the cold atoms trapped by the chip.
A PERCOLATION MODEL OF MOBILE AD-HOC NETWORKS
Authors: MOHAMMADI HOSSEIN , OSKOEE EHSAN NEDAAEE , AFSHARCHI MOHSEN , YAZDANI NASSER , SAHIMI MUHAMMAD
Published: January 2010

Mobile ad-hoc networks (MANETs) are random, self-configurable and rapidly-deployable networks. The main goal of developing the MANETs is not only obtaining better service, but also having networks that can serve in situations in which no other means of communications can operate. Examples include networks that are used in battlefields, in search-and-rescue operations, and networks of sensors. We propose a percolation model for studying the properties of the MANETs. The model is based on a random network of sites, distributed in space, which represent the mobile nodes. Two nodes are linked if they are within each other's transmission ranges. A node may be lost or become inactive if, for example, it runs out of energy (provided by its batteries). A link can be lost if, for example, one of its two end nodes moves outside of the other's transmission range. Extensive Monte Carlo simulations are carried out to study the properties of the model. The network's topology is characterized by a critical transmission range, which is the analogue of the percolation threshold. It is shown that not only can the model take into account several important features of the real MANETs and explain them in physical terms, but also leads to the development of efficient protocols for self-configuration, adaptability, and disaster survival, which are of utmost importance to the practical applications.
NONLINEAR SUPRATRANSMISSION AND NONLINEAR BISTABILITY IN A FORCED LINEAR ARRAY OF ANHARMONIC OSCILLATORS: A COMPUTATIONAL STUDY
Authors: MACÍAS-DÍAZ J. E. , MEDINA-RAMÍREZ I. E.
Published: January 2010

The nonlinear phenomena of supratransmission and bistability in harmonically forced arrays of anharmonic oscillators are studied in the present article. Employing a finite-difference scheme with multiple properties of consistency, we show that these processes are actually present in such nonlinear systems. We show that, for every frequency in the forbidden band-gap of the medium, there exists a critical forcing amplitude above which the propagation of energy into the system from the boundary is inevitable. We provide diagrams of total energy vs amplitude for several values of the parameters of the model studied in this work, as well as a graph establishing the relationship between the critical amplitude at which supratransmission starts vs frequency. Likewise, we establish the existence of a bistable region, where a conducting and an insulating regimes coexist.
EFFECTS OF USER'S TASTES ON PERSONALIZED RECOMMENDATION
Authors: LIU JIAN-GUO , ZHOU TAO , WANG BING-HONG , ZHANG YI-CHENG , GUO QIANG
Published: January 2010

In this paper, based on a weighted projection of the user-object bipartite network, we study the effects of user tastes on the mass-diffusion-based personalized recommendation algorithm, where a user's tastes or interests are defined by the average degree of the objects he has collected. We argue that the initial recommendation power located on the objects should be determined by both of their degree and the user's tastes. By introducing a tunable parameter, the user taste effects on the configuration of initial recommendation power distribution are investigated. The numerical results indicate that the presented algorithm could improve the accuracy, measured by the average ranking score. More importantly, we find that when the data is sparse, the algorithm should give more recommendation power to the objects whose degrees are close to the user's tastes, while when the data becomes dense, it should assign more power on the objects whose degrees are significantly different from user's tastes.
EXTENDED-KNEE WALK FOR HUMANOID ROBOT WITH PARALLEL LINK LEGS
Authors: SAKAMOTO HAJIME , KATAYOSE HARUHIRO , MIYAZAKI KOJI , NAKATSU RYOHEI
Published: January 2010

This paper proposes a method of giving humanoid robots a natural humanlike walk, which we call the extended-knee walk. Unlike the bent-knee walk of most humanoid robots to date, this walk includes a period in which the knee is fully extended. A parallel mechanism is used in the legs and a method of calculating the walk trajectory copes with the difficulty of the singularity in achieving a humanlike walk. The advantages of this walk were verified from two aspects: good visual appearance and good energy efficiency. An experiment comparing the trajectories of the knee angle during walking showed that the walking style produced by the proposed method is more humanlike than the usual walking style of other humanoid robots. The energy efficiency was verified through power consumption and motor temperature measurements and the possibilities for practical use of this method are discussed with reference to the results of the worldwide soccer competition RoboCup 2008.
BIO-INSPIRED LOCOMOTION CONTROL WITH COORDINATION BETWEEN NEURAL OSCILLATORS
Authors: HUANG WEIWEI , CHEW CHEE-MENG , ZHENG YU , HONG GEOK-SOON
Published: January 2010

Central Pattern Generator (CPG) is used in bipedal locomotion control to provide the basic rhythm signal for actuators. Generally, the CPG is composed of many neural oscillators coupled together. In this paper, the coordination between neural oscillators in CPG is studied to achieve robust rhythm motions. By using the entrainment property of the neural oscillator, we develop a method which uses the difference between oscillator's output and desired output to adjust the inner states of neural oscillators. In the simulation, a CPG structure with coordination between neural oscillators is used to control a 2D bipedal robot. The robot can walk continuously when several external forces are applied on the robot during walking. The method is also implemented on our humanoid robot NUSBIP-III ASLAN for the test of walking forward. With the coordination between neural oscillators, the CPG generated rhythmic and robust control signals which enable the robot to walk forward stably.
RUNNING PATTERN GENERATION OF HUMANOID BIPED WITH A FIXED POINT AND ITS REALIZATION
Authors: CHO BAEK-KYU , PARK ILL-WOO , OH JUN-HO
Published: January 2010

This paper discusses the generation of a running pattern for a humanoid biped and verifies the validity of the proposed method of running pattern generation via experiments. Two running patterns are generated independently in the sagittal plane and in the frontal plane and the two patterns are then combined. When a running pattern is created with resolved momentum control in the sagittal plane, the angular momentum of the robot about the Center of Mass (COM) is set to zero, as the angular momentum causes the robot to rotate. However, this also induces unnatural motion of the upper body of the robot. To solve this problem, the biped was set as a virtual under-actuated robot with a free joint at its support ankle, and a fixed point for a virtual under-actuated system was determined. Following this, a periodic running pattern in the sagittal plane was formulated using the fixed point. The fixed point is easily determined in a numerical approach. In this way, a running pattern in the frontal plane was also generated. In an experiment, a humanoid biped known as KHR-2 ran forward using the proposed running pattern generation method. Its maximum velocity was 2.88 km/h.
CARTESIAN APPROACH FOR GAIT PLANNING AND CONTROL OF BIPED ROBOTS ON IRREGULAR SURFACES
Authors: MOOSAVIAN S. ALI A. , ALGHOONEH MANSOOR , TAKHMAR AMIR
Published: January 2010

Biped robots possess higher capabilities than other mobile robots for moving on uneven environments. However, due to natural postural instability of these robots, their motion planning and control become a more important and challenging task. This article presents a Cartesian approach for gait planning and control of biped robots without the need to use the inverse kinematics and the joint space trajectories, thus the proposed approach could substantially reduce the processing time in both simulation studies and online implementations. It is based on constraining four main points of the robot in Cartesian space. This approach exploits the concept of Transpose Jacobian control as a virtual spring and damper between each of these points and the corresponding desired trajectory, which leads to overcome the redundancy problem. These four points include the tip of right and left foot, the hip joint, and the total center of mass (CM). Furthermore, in controlling biped robots based on desired trajectories in the task space, the system may track the desired trajectory while the knee is broken. This problem is solved here using a PD controller which will be called the Knee Stopper. Similarly, another PD controller is proposed as the Trunk Stopper to limit the trunk motion. Obtained simulation results show that the proposed Cartesian approach can be successfully used in tracking desired trajectories on various surfaces with lower computational effort.
Discriminative Phrase-Based Models for Arabic Machine Translation
Authors: España-Bonet Cristina , Giménez Jesús , Màrquez Lluís
Published: January 2010

A design for an Arabic-to-English translation system is presented. The core of the system implements a standard phrase-based statistical machine translation architecture, but it is extended by incorporating a local discriminative phrase selection model to address the semantic ambiguity of Arabic. Local classifiers are trained using linguistic information and context to translate a phrase, and this significantly increases the accuracy in phrase selection with respect to the most frequent translation traditionally considered. These classifiers are integrated into the translation system so that the global task gets benefits from the discriminative learning. As a result, we obtain significant improvements in the full translation task at the lexical, syntactic, and semantic levels as measured by an heterogeneous set of automatic evaluation metrics.
Sura Length and Lexical Probability Estimation in Cluster Analysis of the Qur’an
Authors: Moisl Hermann
Published: January 2010

Thabet [2005] applied cluster analysis to the Qur’an in the hope of generating a classification of the (suras) that is useful for understanding of its thematic structure. The result was positive, but variation in (sura) length was a problem because clustering of the shorter was found to be unreliable. The present discussion addresses this problem in four parts. The first part summarizes Thabet’s work. The second part argues that unreliable clustering of the shorter is a consequence of poor estimation of lexical population probabilities in those. The third part proposes a solution to the problem based on calculation of a minimum length threshold using concepts from statistical sampling theory followed by selection of and lexical variables based on that threshold. The fourth part applies the proposed solution to a reanalysis of the Qur’an.
ON MODELINGThe language/action model of conversation
Authors: Jones Peter H.
Published: January 2010

Editor's Note: In last year's January + February issue Usman Haque, Paul Pangaro, and I described several types of interaction---reacting, regulating, learning, balancing, managing, and conversing. In the July + August 2009 issue, Paul Pangaro and I described several types of conversing---agreeing, learning, coordinating, and collaborating---and we proposed using models based on Gordon Pask's Conversation Theory as a guide for improving human-computer interaction. Peter Jones responded, noting that there are other models of conversation and prior work in bringing conversation to human-computer interaction in particular Winograd and Flores 1986 work with The Coordinator. We agree on the importance of The Coordinator and invited Peter to outline the history of models of conversation and their relationship to HCI. His response follows.---Hugh Dubberly
On the energy efficiency of cooperative communications in wireless sensor networks
Authors: Sadek Ahmed K. , Yu Wei , Liu K. J. Ray
Published: January 2010

Cooperative communications represent a potential candidate to combat the effects of channel fading and to increase the transmit energy efficiency in wireless sensor networks with the downside being the increased complexity. In sensor networks the power consumed in the receiving and processing circuitry can constitute a significant portion of the total consumed power. By taking into consideration such overhead, an analytical framework for studying the energy efficiency trade-off of cooperation in sensor networks is presented. This trade-off is shown to depend on several parameters such as the receive and processing power, the required quality-of-service, the power amplifier loss, and several other factors. The analytical and numerical results reveal that for small distance separation between the source and destination, direct transmission is more energy efficient than relaying. The results also reveal that equal power allocation performs as well as optimal power allocation for some scenarios. The effects of the relay location and the number of employed relays on energy efficiency are also investigated in this work. Moreover, there are experimental results conducted to verify the channel model assumed in the article.
Research challenges for digital archives of 3D cultural heritage models
Authors: Koller David , Frischer Bernard , Humphreys Greg
Published: January 2010

The increasing creation of 3D cultural heritage models has resulted in a need for the establishment of centralized digital archives. We advocate open repositories of scientifically authenticated 3D models based on the example of traditional scholarly journals, with standard mechanisms for preservation, peer review, publication, updating, and dissemination of the 3D models. However, fully realizing this vision will require addressing a number of related research challenges.

In this article, we first give a brief background of the virtual heritage discipline, and characterize the need for centralized 3D archives, including a preliminary needs assessment survey of virtual heritage practitioners. Then we describe several existing 3D cultural heritage repositories, and enumerate a number of technical research challenges that should be addressed to realize an ideal archive. These challenges include digital rights management for the 3D models, clear depiction of uncertainty in 3D reconstructions, version control for 3D models, effective metadata structures, long-term preservation, interoperability, and 3D searching. Other concerns are provision for the application of computational analysis tools, and the organizational structure of a peer-reviewed 3D model archive.
An adaptative game loop architecture with automatic distribution of tasks between CPU and GPU
Authors: Joselli Mark , Zamith Marcelo , Clua Esteban , Montenegro Anselmo , Leal-Toledo Regina , Conci Aura , Pagliosa Paulo , Valente Luis , Feijó Bruno
Published: January 2010

This article presents a new architecture to implement all game loop models for games and real-time applications that use the GPU as a mathematics and physics coprocessor, working in parallel processing mode with the CPU. The presented model applies automatic task distribution concepts. The architecture can apply a set of heuristics defined in Lua scripts in order to get acquainted with the best processor for handling a given task. The model applies the GPGPU (general-purpose computation on GPUs) paradigm. In this article we propose an architecture that acquires knowledge about the hardware by running tasks in each processor and, by studying their performance over time, finding the best processor for a group of tasks.
Enhanced physically-based animation of deformable bodies using shape-matching
Authors: Atencio Yalmar Ponce , Alzamora Guina Sotomayor , Esperança Claudio
Published: January 2010

We present a simplified approach for the animation of geometrically complex deformable objects represented by tetrahedral meshes. Our prototype system detects and responds to collisions of objects that are subject to elastic deformations of variable stiffness. The proposed approach combines several techniques, namely, collision detection using spatial hashing, collision response with consistent penetration depth obtained by propagation, estimated displacement vectors for the deformation region, and binary search to separate objects. The dynamics is based on shape-matching and a modal analysis scheme, using an Euler explicit-implicit integrator. Preliminary results show that collisions between objects containing several hundreds tetrahedra can be animated in real time.
Smart composition of game objects using dependency injection
Authors: Passos Erick B. , Sousa Jonhnny Weslley S. , Clua Esteban Walter Gonzales , Montenegro Anselmo , Murta Leonardo
Published: January 2010

Most game engines are based on inheritance of game objects and/or componentization of behaviors. While this approach enables clear visualization of the system architecture, good code reuse, and fast prototyping, it brings some issues, mostly related to the high dependency between game objects/components instances. This dependency often leads to static casts and null pointer references that are difficult to debug. In this article we propose the use of the dependency injection design pattern to safely initialize game objects and lessen the programmer's role in handling these issues both during the prototyping and production phases. Since these dependencies are attributes of game objects and the injection occurs only at the initialization pass, there is no performance penalty at the game loop.
Event relations in plan-based plot composition
Authors: Ciarlini Angelo E. M. , Barbosa Simone D. J. , Casanova Marco A. , Furtado Antonio L.
Published: January 2010

The process of plot composition in the context of interactive storytelling is considered from a fourfold perspective, that is, from the syntagmatic, paradigmatic, antithetic, and meronymic relations between the constituent events. These relations are shown to be associated with the four major tropes of semiotic research. A conceptual model and set of facilities for interactive plot composition and adaptation dealing with the four relations is described. To accommodate antithetic relations, corresponding to the irony trope, our plan-based approach leaves room for the unplanned. A simple storyboarding prototype tool has been implemented to conduct experiments.
Parallel culling and sorting based on adaptive static balancing
Authors: Machado Lucas , Feijó Bruno
Published: January 2010

This article presents a new and effective method for parallel octree culling and sorting for multicore systems, using counting sort and based on a new balancing algorithm, called adaptive delayed static balancing. The adaptive nature of the method is governed by a dynamic split level that can adjust the algorithm to new camera positions, keeping a well-balanced workload among the processors. This article also introduces the concept of n-dimensional resource space as a discrete Euclidean space. This work presents a simple and effective thread management system, called MinTMS.
Locally Linear Discriminate Embedding for Face Recognition
Authors: Abusham Eimad E. , Wong E. K.
Published: January 2010

A novel method based on the local nonlinear mapping is presented in this research. The method is called Locally Linear Discriminate Embedding (LLDE). LLDE preserves a local linear structure of a high‐dimensional space and obtains a compact data representation as accurately as possible in embedding space (low dimensional) before recognition. For computational simplicity and fast processing, Radial Basis Function (RBF) classifier is integrated with the LLDE. RBF classifier is carried out onto low‐dimensional embedding with reference to the variance of the data. To validate the proposed method, CMU‐PIE database has been used and experiments conducted in this research revealed the efficiency of the proposed methods in face recognition, as compared to the linear and non‐linear approaches.