bluuebunny/crossref_metadata_2025 huggingface dataset:
CA-074Me Protection against Anthrax Lethal Toxin
Authors: Newman Zachary L. , Leppla Stephen H. , Moayeri Mahtab
Published: July 2009

Anthrax lethal toxin (LT) activates the NLRP1b (NALP1b) inflammasome and caspase-1 in macrophages from certain inbred mouse strains, but the mechanism by which this occurs is poorly understood. We report here that similar to several NLRP3 (NALP3, cryopyrin)-activating stimuli, LT activation of the NLRP1b inflammasome involves lysosomal membrane permeabilization (LMP) and subsequent cytoplasmic cathepsin B activity. CA-074Me, a potent cathepsin B inhibitor, protects LT-sensitive macrophages from cell death and prevents the activation of caspase-1. RNA interference knockdown of cathepsin B expression, however, cannot prevent LT-mediated cell death, suggesting that CA-074Me may also act on other cellular proteases released during LMP. CA-074Me appears to function downstream of LT translocation to the cytosol (as assessed by mitogen-activated protein kinase kinase cleavage), K
+
effluxes, and proteasome activity. The initial increase in cytoplasmic activity of cathepsin B occurs at the same time or shortly before caspase-1 activation but precedes a larger-scale lysosomal destabilization correlated closely with cytolysis. We present results suggesting that LMP may be involved in the activation of the NLRP1b inflammasome.
Quality of reporting in sports injury prevention abstracts according to the CONSORT and STROBE criteria: an analysis of the World Congress of Sports Injury Prevention in 2005 and 2008
Authors: Yoon Uzung , Knobloch Karsten
Published: July 2009

Objective

The quality of reporting in congress abstracts is likely to influence clinical decision-making.

Hypothesis

The quality of reporting in sports injury prevention abstracts has increased over the last 3 years, as did the number of randomised controlled trials (RCT).

Methods

154 abstracts from the 2005 and 186 abstracts from 2008 World Conferences on Sports Injury Prevention in Norway were analysed.

Main outcome measures

Scores of 17 Consolidated Standards of Reporting Trials (CONSORT) criteria for RCT, or 22 Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria for observational studies were determined.

Results

Improvement in reporting was evident in RCT (CONSORT score 5.8±0.9 vs 8.6±2.9, p=0.001, CI −4.29 to −1.43) as well as for observational studies (STROBE score 7.9±1.6 vs 9.9±1.7, p<0.001, CI −2.34 to −1.53) between 2005 and 2008. RCTs were published in 9.1% in 2005 versus 10.2% in 2008 (p=0.727). RCT demonstrated a significant improvement in main outcome (0% vs 57.9%, p<0.001). For observational studies, a significant improvement was reported in rationale (53.5% vs 98.2%, p<0.001), objectives (82.2% vs 95.1%, p=0.012), study design (25.2% vs 65%, p<0.001), setting (43.7% vs 65.6%, p=0.002), variables (20.7% vs 74.2%, p<0.001), participants (0.7% vs 10.4%, p=0.001) and funding (0% vs 5.5%, p=0.006).

Conclusion

While the percentage of published RCTs in abstracts at the World Congress of Sports Injury Prevention remained unchanged, an improvement in reporting of abstracts was evident from 2005 to 2008, as determined by CONSORT/STROBE criteria. However, substantial and comprehensive use of the CONSORT and STROBE criteria might further increase the quality of reporting of sports injury conference abstracts in the future.
eSlide suite: an open source software system for whole slide imaging
Authors: Mea V Della , Bortolotti N , Beltrami C A
Published: July 2009

This short report briefly describes the principles underlying the telepathology technique known as whole slide imaging, and the design and implementation of a system for acquisition and visualisation of digital slides. The developed system, including an acquisition module and a visualisation module, is available as an open source on the Internet, together with sample acquired slides.
Rapid blood separation is superior to fluoride for preventing in vitro reductions in measured blood glucose concentration: Figure 1
Authors: Shi R Z , Seeley E S , Bowen R , Faix J D
Published: July 2009

Aims:

To determine whether tubes containing sodium fluoride negatively bias blood glucose concentration by directly comparing glucose concentrations in paired blood samples collected in tubes containing lithium heparin (Li-Heparin) and tubes containing sodium fluoride/potassium oxalate (NaF-KOx).

Methods:

Paired blood samples from a group of patients (n = 1040) were collected in tubes containing Li-Heparin and tubes containing NaF-KOx at the same time. All Li-Heparin samples were centrifuged soon after collection and were kept cool in transport along with NaF-KOx samples, which were centrifuged at the receiving location after an average transport time of 4 h, but immediately before analysis. Glucose concentrations in the paired samples were determined simultaneously by an automated oxidase method.

Results:

The mean glucose concentrations for NaF-KOx samples and Li-Heparin samples were 5.7 mmol/l and 6.1 mmol/l, respectively, with a mean difference of 0.39 mmol/l.

Conclusion:

Rapid separation of heparinised blood is superior to fluoride alone for abrogating glycolytic effects on blood glucose measurements in the clinical laboratory.
Myeloid sarcoma of the small bowel associated with a CBFβ/MYH11 fusion and inv(16)(p13q22): a case report
Authors: McKenna M , Arnold C , Catherwood M A , Humphreys M W , Cuthbert R J G , Bueso-Ramos C , McManus D T
Published: July 2009

This report describes a case of aleukaemic myeloid sarcoma of the small intestine in a 50-year-old woman presenting with small bowel obstruction. Fluorescence in situ hybridisation analysis of interphase nuclei revealed a split CBFβ signal, consistent with an underlying inversion of chromosome 16, inv(16)(p13q22). The resultant type A CBFβ/MYH11 transcript was detected by reverse transcriptase PCR. Immunohistochemistry with the AH107 antibody to the CBFβ–SMMHC chimeric protein showed strong nuclear staining of the tumour cell nuclei. This represents the first use of this antibody in the diagnosis of this subtype of myeloid sarcoma in the small intestine.
Lynch syndrome (hereditary non-polyposis colorectal cancer) and endometrial carcinoma
Authors: Garg K , Soslow R A
Published: July 2009

Women with hereditary non-polyposis colorectal cancer (HNPCC)/Lynch syndrome have a high risk for endometrial cancer (EC) and frequently present with a gynaecological cancer as their first or sentinel malignancy. Identification of these patients is important given their personal and family risk for synchronous and metachronous tumours. Modalities to detect ECs for the possibility of HNPCC include microsatellite instability assay, immunohistochemistry for DNA mismatch repair proteins, MLH1 promoter hypermethylation assay and mutational analysis of DNA mismatch repair genes. The revised Bethesda guidelines provide screening criteria for HNPCC in colorectal cancers (CRCs). However, there are currently no such screening recommendations for women with endometrial carcinoma. While age and family history are useful screening criteria, their sensitivity has been shown to be low for detection of HNPCC in EC. Expansion of these criteria to include tumour morphology (presence of tumour infiltrating lymphocytes and tumour heterogeneity including dedifferentiated/undifferentiated ECs) and topography (lower uterine segment localisation) as well as presence of synchronous ovarian clear cell carcinomas may significantly enhance the detection of patients with EC at risk for HNPCC. Consideration should be given to incorporating these screening criteria into a revision of the Bethesda guidelines for detecting EC patients at highest risk for HNPCC.
The expression of adiponectin receptors Adipo-R1 and Adipo-R2 is associated with an intestinal histotype and longer survival in gastric carcinoma
Authors: Barresi V , Grosso M , Giuffrè G , Tuccari G , Barresi G
Published: July 2009

Background:

Adiponectin (ApN) is a 30 kDa adipocytokine which mediates an antineoplastic effect after binding to its receptors, Adipo-R1 and Adipo-R2. The expression of these receptors has been documented in gastric cancer (GC) cell lines, but only a few data exist on their expression in GC neoplastic tissue.

Aim:

To investigate the expression of Adipo-R1 and Adipo-R2 in a series of surgically resected GCs and to assess its association with various tumour clinicopathological characteristics as well as with patient survival.

Methods:

Forty-nine surgically resected GCs were submitted to immunohistochemical assays for Adipo-R1, Adipo-R2 and ApN.

Results:

Adipo-R1 and Adipo-R2 immunoexpression was found in 22/49 GCs and in intestinal metaplasia areas near the tumours, whereas only slight immunoreactivity for these proteins was found in adjacent normal gastric epithelium. No ApN expression was encountered in any of the cases analysed. Adipo-R1/Adipo-R2 expression was significantly associated with an intestinal histotype of the tumours and with longer overall survival of the patients.

Conclusions:

Intestinal-type GCs often express Adipo-R1/R2 in association with a better prognosis. The presence of these receptors could be exploited for novel anticancer therapies based on ApN addition in GC.
Lupus anticoagulant: case-based external quality assessment
Authors: van den Besselaar A M H P , Devreese K M J , de Groot P G , Castel A
Published: July 2009

Aims:

A model for presenting case histories with quality assessment material is to be developed for the Dutch external quality assessment (EQA) scheme for blood coagulation testing. The purpose of the present study was to assess the performance of clinical laboratories in case-based EQA using the case history of a patient suffering from lupus erythematosus of the skin.

Methods:

Along with the case history, a freeze-dried plasma sample from the patient was distributed to the participants of the Dutch EQA scheme for blood coagulation testing. The participants were requested to report their coagulation test results, interpretation of the test results, and suggestions for further testing.

Results:

The response rate was 65%. Tests for lupus anticoagulant were performed by 27% of the respondents and mixing experiments by 32%. The interpretation of the test results was heterogeneous but the presence of lupus anticoagulant was suggested by 54% of the respondents. A substantial number of respondents (23%) did not provide any interpretation. Only few participants followed the sequential steps for lupus anticoagulant identification recommended by the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis.

Conclusions:

Case-based EQA is useful as an educational postanalytical tool. Several limitations were noted, and these included the limited volume of the sample, the different matrix of the freeze-dried sample compared with a fresh sample, and the time lag between the case history and the preparation of the freeze-dried sample.
ISOTROPY SUBGROUP OF HURWITZ ACTION OF THE 3-BRAID GROUP ON THE BRAID SYSTEMS
Authors: YAGUCHI YOSHIRO
Published: July 2009

The Hurwitz action of the n-braid group Bn on the n-fold direct product Bmn of the m-braid group Bm is studied. We show that the isotropy subgroup of the Hurwitz group action of B3 at the triple of the standard generators of B4 has index 16, by explicitly describing a complete system of coset representatives. An application to the braided surfaces in 4-space is also given.
TESTING AND FORMAL VERIFICATION OF SERVICE ORIENTED ARCHITECTURES
Authors: SLOAN JOHN C. , KHOSHGOFTAAR TAGHI M.
Published: July 2009

We examine two open engineering problems in the area of testing and formal verification of internet-enabled service oriented architectures (SOA). The first involves deciding when to formally and exhaustively verify versus when to informally and non-exhaustively test. The second concerns scalability limitations associated with formal verification, to which we propose a semi-formal technique that uses software agents. Finally, we assess how these findings can improve current software quality assurance practices.

Addressing the first problem, we present and explain two classes of tradeoffs. External tradeoffs between assurance, performance, and flexibility are determined by the business needs of each application, whether it be in engineering, commerce, or entertainment. Internal tradeoffs between assurance, scale, and level of detail involve the technical challenges of feasibly verifying or testing an SOA. To help decide whether to exhaustively verify or non-exhaustively test, we present and explain these two classes of tradeoffs.

Identifying a middle ground between testing and verification, we propose using software agents to simulate services in a composition. Technologically, this approach has the advantage of assuring the quality of compositions that are too large to exhaustively verify. Operationally, it supports testing these compositions in the laboratory without access to source code or use of network resources of third-party services. We identify and exploit the structural similarities between agents and services, examining how doing so can assure the quality of service compositions.
RELIABILITY ASSESSMENT OF SAFETY INSTRUMENTED SYSTEMS IN THE OIL AND GAS INDUSTRY: A PRACTICAL APPROACH AND A CASE STUDY
Authors: LUNDTEIGEN MARY ANN , RAUSAND MARVIN
Published: July 2009

This article presents a practical approach to reliability assessment of a complex safety instrumented system that is susceptible to common cause failures. The approach is based on fault tree analysis where the common cause failures are included by post-processing the minimal cut sets. The approach is illustrated by a case study of a safety instrumented function of a workover control system that is used during maintenance interventions into subsea oil and gas wells. The case study shows that the approach is well suited for identifying potential failures in complex systems and for including design engineers in the verification of the reliability analyses. Unlike many software tools for fault tree analysis, the approach gives conservative estimates for reliability. The suggested approach represents a useful extension to current reliability analysis methods.
Alternative Formulas to Compute Implied Standard Deviation
Authors: Ang James S. , Jou Gwoduan David , Lai Tsong-Yue
Published: July 2009

We assume that the call option's value is correctly priced by Black and Scholes' option pricing model in this paper. This paper derives an exact closed-form solution for implied standard deviation under the condition that the underlying asset price equals the present value of the exercise price. The exact closed-form solution provides the true implied standard deviation and has no estimate error. This paper also develops three alternative formulas to estimate the implied standard deviation if this condition is violated. Application of the Taylor expansion on a single call option value derives the first formula. The accuracy of this formula depends on the deviation between the underlying asset price and the present value of the exercise price. Use of the Taylor formula on two call option prices with different exercise prices is used to develop the second formula, which can be used even though the underlying asset price deviates significantly from the present value of the exercise price. Extension of the second formula's approach to third options value derives the third formula. A merit of the third formula is to circumvent a required parameter used in the second formula. Simulations demonstrate that the implied standard deviations calculated by the second and third formulas provide accurate estimates of the true implied standard deviations.
Institutional Ownership and Income Smoothing by Japanese Banks through Loan Loss Provisions
Authors: Kwak Wikil , Lee Ho-Young , Mande Vivek
Published: July 2009

This paper examines the association between institutional ownership and income smoothing through bank loan loss provisions for a sample of Japanese banks during the period 1991–1999. We find that as the percentage of institutional ownership of banks increases, income smoothing via loan loss provisions increases. Additional tests show that there is a significant positive relationship between the extent of income smoothing and the percentage ownership of banks by domestic financial institutions and affiliated (keiretsu) institutions. Consistent with the idea that foreign institutional holders do not play an important role in the corporate governance of Japanese banks, we do not find a significant association between foreign institutional ownership and the extent of income smoothing. Our results imply that institutional owners may play a different role in monitoring income smoothing during the recessionary period in Japan from the normal economic periods studied in most prior studies.
The Relationship between European Convertible Bond Issues and Corporate Governance: A Study of Electronics Companies in Taiwan
Authors: Huang Jen-Hung , Huang Hyley , Lee Cheng-Few
Published: July 2009

The purpose of this paper is to study the relationship between European convertible bond issues and corporate governance. After reviewing the regulation of Taiwan's ECB issues, we use the data from publicly traded electronics stocks from Taiwan to perform the empirical study. We found that the larger the company's ECB issue size, the higher the premium at the time of the ECB issue. In addition, we also found that the higher the company debt ratio, the lower the ECB issue premium. Finally, we found that the larger the company market value, the larger the size of the ECB issue.
Variation in Stock Return Risks: An International Comparison
Authors: Chiou Wan-Jiun Paul , Lee Alice C. , Lee Cheng-Few
Published: July 2009

Using returns of 4,916 stocks from 22 developed countries and 15 developing countries, this study examines the relative magnitude of conditional volatility and the international market systematic risk of stock prices in countries at different developmental stages and in various geographical areas. Consistent with the finding of Bekaert et al. (2008), the results of non-parametric Mann-Whitney tests suggest that the stock prices in emerging markets are riskier than the ones in developed countries, measured by both conditional volatility and global beta. Our empirical findings also support the geographical variation in stock risks. Specifically, the equity values in Southeast Asia, South Europe, and Latin America are more volatile than the rest of the world. Similar results can be found in the country-level tests. The time-series analysis suggests that the stock returns in high risk countries tend to be less volatile but the conditional volatility of stock return in less risky countries leans to increase.
IDENTIFICATION OF DAMPING PARAMETERS OF LINEAR DYNAMIC SYSTEM
Authors: ROY SAJAL , CHAKRABORTY SUBRATA
Published: July 2009

The identification of damping in a structural system is extremely important for reliable prediction of response of dynamic systems. The present study focuses on the damping parameters identification of linear multi-degree of freedom (MDOF) systems defined by Rayleigh damping model. A system identification (SI) algorithm based on the free vibration response of structures is proposed to identify the damping parameters. In doing so, the equation error based SI approach is readily developed for identification of damping properties at element level. The formulation is elucidated using numerically simulated modal data obtained through finite element analysis. The robustness of the algorithm is also studied by Monte Carlo simulation based error sensitivity analysis. The identified damping values are found to be in consistent with those of pre-assigned values used to simulate modal data.
LATERAL-FLEXURAL AND TORSIONAL VIBRATIONS OF FLEXIBLE RING FOR ELECTROMECHANICAL INTEGRATED ELECTROSTATIC HARMONIC ACTUATOR
Authors: XU LIZHONG , LI YAOWU
Published: July 2009

This paper presents an electromechanical coupled dynamic equation for the lateral-flexural and torsional vibrations of a flexible ring for an electromechanical integrated electrostatic harmonic actuator as well as the equation of the forced response of the electromechanical integrated electrostatic harmonic actuator to voltage excitation. By solving these equations, the natural frequency and vibration modes of the flexible ring for the actuator are investigated. Changes in the natural frequency with respect to the main system parameters are also examined and the dynamic responses of the actuator to voltage excitation obtained.
PatchMatch
Authors: Barnes Connelly , Shechtman Eli , Finkelstein Adam , Goldman Dan B
Published: July 2009

This paper presents interactive image editing tools using a new randomized algorithm for quickly finding approximate nearest-neighbor matches between image patches. Previous research in graphics and vision has leveraged such nearest-neighbor searches to provide a variety of high-level digital image editing tools. However, the cost of computing a field of such matches for an entire image has eluded previous efforts to provide interactive performance. Our algorithm offers substantial performance improvements over the previous state of the art (20-100x), enabling its use in interactive editing tools. The key insights driving the algorithm are that some good patch matches can be found via random sampling, and that natural coherence in the imagery allows us to propagate such matches quickly to surrounding areas. We offer theoretical analysis of the convergence properties of the algorithm, as well as empirical and practical evidence for its high quality and performance. This one simple algorithm forms the basis for a variety of tools -- image retargeting, completion and reshuffling -- that can be used together in the context of a high-level image editing application. Finally, we propose additional intuitive constraints on the synthesis process that offer the user a level of control unavailable in previous methods.
Light warping for enhanced surface depiction
Authors: Vergne Romain , Pacanowski Romain , Barla Pascal , Granier Xavier , Schlick Christophe
Published: July 2009

Recent research on the human visual system shows that our perception of object shape relies in part on compression and stretching of the reflected lighting environment onto its surface. We use this property to enhance the shape depiction of 3D objects by locally warping the environment lighting around main surface features. Contrary to previous work, which require specific illumination, material characteristics and/or stylization choices, our approach enhances surface shape without impairing the desired appearance.

Thanks to our novel local shape descriptor, salient surface features are explicitly extracted in a view-dependent fashion at various scales without the need of any pre-process. We demonstrate our system on a variety of rendering settings, using object materials ranging from diffuse to glossy, to mirror or refractive, with direct or global illumination, and providing styles that range from photorealistic to non-photorealistic. The warping itself is very fast to compute on modern graphics hardware, enabling real-time performance in direct illumination scenarios.

Note: Third-Party Material Attribution
Third-party material used in ACM Transactions on Graphics 28(3), Article 25 - "Light Warping for Enhanced Surface Depiction," by Vergne, Pacanowski, Barla, Granier, and Schlick - was used without proper attribution.

The 3D model used in Figures 1, 3, and 5, as well as in the cover image of this volume of the journal, was downloaded from the Shape Repository of AIM@SHAPE Project (http://shapes.aimatshape.net) and is the property of CNR-IMATI.

We regret this oversight.
Toward evaluating lighting design interface paradigms for novice users
Authors: Kerr William B. , Pellacini Fabio
Published: July 2009

Lighting design is a complex but fundamental task in computer cinematography, involving the adjustment of light parameters to define final scene appearance. Many user interfaces have been proposed to simplify lighting design. They can be generally categorized in three paradigms: direct light parameter manipulation, indirect light feature manipulation (e.g., shadow dragging), and goal-based optimization of lighting through painting. To this date, no formal evaluation of the relative effectiveness of these paradigms has been performed.

In this paper, we present a first step toward evaluating the benefits of these three paradigms in the form of a user study with a focus on novice users. 20 subjects participated in the experiment by performing various trials on simple scenes with up to 8 point lights, designed to test two lighting tasks: precise adjustment of lighting and the artistic exploration of lighting configurations. We collected objective and subjective data and found that subjects can light well with direct and indirect interfaces, preferring the latter. Paint-based goal specification was found to be significantly worse than the other paradigms, especially since users tend to sketch rather than accurately paint goal images, an input that painting algorithms were not designed for. We also found that given enough time, novices can perform relatively complex lighting tasks, unhindered by geometry or lighting complexity. Finally, we believe that our study will impact the design of future lighting interfaces and it will serve as the basis for designing additional experiments to reach a comprehensive evaluation of lighting interfaces.
How well do line drawings depict shape?
Authors: Cole Forrester , Sanik Kevin , DeCarlo Doug , Finkelstein Adam , Funkhouser Thomas , Rusinkiewicz Szymon , Singh Manish
Published: July 2009

This paper investigates the ability of sparse line drawings to depict 3D shape. We perform a study in which people are shown an image of one of twelve 3D objects depicted with one of six styles and asked to orient a gauge to coincide with the surface normal at many positions on the object's surface. The normal estimates are compared with each other and with ground truth data provided by a registered 3D surface model to analyze accuracy and precision. The paper describes the design decisions made in collecting a large data set (275,000 gauge measurements) and provides analysis to answer questions about how well people interpret shapes from drawings. Our findings suggest that people interpret certain shapes almost as well from a line drawing as from a shaded image, that current computer graphics line drawing techniques can effectively depict shape and even match the effectiveness of artist's drawings, and that errors in depiction are often localized and can be traced to particular properties of the lines used. The data collected for this study will become a publicly available resource for further studies of this type.
Fabricating microgeometry for custom surface reflectance
Authors: Weyrich Tim , Peers Pieter , Matusik Wojciech , Rusinkiewicz Szymon
Published: July 2009

We propose a system for manufacturing physical surfaces that, in aggregate, exhibit a desired surface appearance. Our system begins with a user specification of a BRDF, or simply a highlight shape, and infers the required distribution of surface slopes. We sample this distribution, optimize for a maximally-continuous and valley-minimizing height field, and finally mill the surface using a computer-controlled machine tool. We demonstrate a variety of surfaces, ranging from reproductions of measured BRDFs to materials with unconventional highlights.
Joint-aware manipulation of deformable models
Authors: Xu Weiwei , Wang Jun , Yin KangKang , Zhou Kun , van de Panne Michiel , Chen Falai , Guo Baining
Published: July 2009

Complex mesh models of man-made objects often consist of multiple components connected by various types of joints. We propose a joint-aware deformation framework that supports the direct manipulation of an arbitrary mix of rigid and deformable components. First we apply slippable motion analysis to automatically detect multiple types of joint constraints that are implicit in model geometry. For single-component geometry or models with disconnected components, we support user-defined virtual joints. Then we integrate manipulation handle constraints, multiple components, joint constraints, joint limits, and deformation energies into a single volumetric-cell-based space deformation problem. An iterative, parallelized Gauss-Newton solver is used to solve the resulting nonlinear optimization. Interactive deformable manipulation is demonstrated on a variety of geometric models while automatically respecting their multi-component nature and the natural behavior of their joints.
Semantic deformation transfer
Authors: Baran Ilya , Vlasic Daniel , Grinspun Eitan , Popović Jovan
Published: July 2009

Transferring existing mesh deformation from one character to another is a simple way to accelerate the laborious process of mesh animation. In many cases, it is useful to preserve the semantic characteristics of the motion instead of its literal deformation. For example, when applying the walking motion of a human to a flamingo, the knees should bend in the opposite direction. Semantic deformation transfer accomplishes this task with a shape space that enables interpolation and projection with standard linear algebra. Given several example mesh pairs, semantic deformation transfer infers a correspondence between the shape spaces of the two characters. This enables automatic transfer of new poses and animations.
Modular bases for fluid dynamics
Authors: Wicke Martin , Stanton Matt , Treuille Adrien
Published: July 2009

We present a new approach to fluid simulation that balances the speed of model reduction with the flexibility of grid-based methods. We construct a set of composable reduced models, or
tiles
, which capture spatially localized fluid behavior. We then precompute coupling terms so that these models can be rearranged at runtime. To enforce consistency between tiles, we introduce
constraint reduction
. This technique modifies a reduced model so that a given set of linear constraints can be fulfilled. Because dynamics and constraints can be solved entirely in the reduced space, our method is extremely fast and scales to large domains.
Predictive-corrective incompressible SPH
Authors: Solenthaler B. , Pajarola R.
Published: July 2009

We present a novel, incompressible fluid simulation method based on the Lagrangian
Smoothed Particle Hydrodynamics
(SPH) model. In our method, incompressibility is enforced by using a prediction-correction scheme to determine the particle pressures. For this, the information about density fluctuations is actively propagated through the fluid and pressure values are updated until the targeted density is satisfied. With this approach, we avoid the computational expenses of solving a pressure Poisson equation, while still being able to use large time steps in the simulation. The achieved results show that our
predictive-corrective incompressible
SPH (PCISPH) method clearly outperforms the commonly used
weakly compressible
SPH (WCSPH) model by more than an order of magnitude while the computations are in good agreement with the WCSPH results.
Bi-3
C
2
polar subdivision
Authors: Myles Ashish , Peters Jörg
Published: July 2009

Popular subdivision algorithms like Catmull-Clark and Loop are
C
2
almost everywhere, but suffer from shape artifacts and reduced smoothness exactly near the so-called "extraordinary vertices" that motivate their use. Subdivision theory explains that inherently, for standard stationary subdivision algorithms, curvature-continuity and the ability to model all quadratic shapes requires a degree of at least bi-6. The existence of a simple-to-implement
C
2
subdivision algorithm generating surfaces of good shape and piecewise degree bi-3 in the polar setting is therefore a welcome surprise. This paper presents such an algorithm, the underlying insights, and a detailed analysis. In bi-3
C
2
polar subdivision the weights depend, as in standard schemes, only on the valence, but the valence at one central polar vertex increases to match Catmull-Clark-refinement.
Procedural noise using sparse Gabor convolution
Authors: Lagae Ares , Lefebvre Sylvain , Drettakis George , Dutré Philip
Published: July 2009

Noise is an essential tool for texturing and modeling. Designing interesting textures with noise calls for accurate spectral control, since noise is best described in terms of spectral content. Texturing requires that noise can be easily mapped to a surface, while high-quality rendering requires anisotropic filtering. A noise function that is procedural and fast to evaluate offers several additional advantages. Unfortunately, no existing noise combines all of these properties.

In this paper we introduce a noise based on sparse convolution and the Gabor kernel that enables all of these properties. Our noise offers accurate spectral control with intuitive parameters such as orientation, principal frequency and bandwidth. Our noise supports two-dimensional and solid noise, but we also introduce setup-free surface noise. This is a method for mapping noise onto a surface, complementary to solid noise, that maintains the appearance of the noise pattern along the object and does not require a texture parameterization. Our approach requires only a few bytes of storage, does not use discretely sampled data, and is nonperiodic. It supports anisotropy and anisotropic filtering. We demonstrate our noise using an interactive tool for noise design.
Eye-catching crowds
Authors: McDonnell Rachel , Larkin Michéal , Hernández Benjamín , Rudomin Isaac , O'Sullivan Carol
Published: July 2009

Populated virtual environments need to be simulated with as much variety as possible. By identifying the most salient parts of the scene and characters, available resources can be concentrated where they are needed most. In this paper, we investigate which body parts of virtual characters are most looked at in scenes containing duplicate characters or
clones
. Using an eye-tracking device, we recorded fixations on body parts while participants were asked to indicate whether clones were present or not. We found that the head and upper torso attract the majority of first fixations in a scene and are attended to most. This is true regardless of the orientation, presence or absence of motion, sex, age, size, and clothing style of the character. We developed a selective variation method to exploit this knowledge and perceptually validated our method. We found that selective colour variation is as effective at generating the illusion of variety as full colour variation. We then evaluated the effectiveness of four variation methods that varied only salient parts of the characters. We found that head accessories, top texture and face texture variation are all equally effective at creating variety, whereas facial geometry alterations are less so. Performance implications and guidelines are presented.
Example-based hair geometry synthesis
Authors: Wang Lvdi , Yu Yizhou , Zhou Kun , Guo Baining
Published: July 2009

We present an example-based approach to hair modeling because creating hairstyles either manually or through image-based acquisition is a costly and time-consuming process. We introduce a hierarchical hair synthesis framework that views a hairstyle both as a 3D vector field and a 2D arrangement of hair strands on the scalp. Since hair forms wisps, a hierarchical hair clustering algorithm has been developed for detecting wisps in example hairstyles. The coarsest level of the output hairstyle is synthesized using traditional 2D texture synthesis techniques. Synthesizing finer levels of the hierarchy is based on cluster oriented detail transfer. Finally, we compute a discrete tangent vector field from the synthesized hair at every level of the hierarchy to remove undesired inconsistencies among hair trajectories. Improved hair trajectories can be extracted from the vector field. Based on our automatic hair synthesis method, we have also developed simple user-controlled synthesis and editing techniques including feature-preserving combing as well as detail transfer between different hairstyles.
Optimal gait and form for animal locomotion
Authors: Wampler Kevin , Popović Zoran
Published: July 2009

We present a fully automatic method for generating gaits and morphologies for legged animal locomotion. Given a specific animal's shape we can determine an efficient gait with which it can move. Similarly, we can also adapt the animal's morphology to be optimal for a specific locomotion task. We show that determining such gaits is possible without the need to specify a good initial motion, and without manually restricting the allowed gaits of each animal. Our approach is based on a hybrid optimization method which combines an efficient derivative-aware spacetime constraints optimization with a derivative-free approach able to find non-local solutions in high-dimensional discontinuous spaces. We demonstrate the effectiveness of this approach by synthesizing dynamic locomotions of bipeds, a quadruped, and an imaginary five-legged creature.
Achieving eye contact in a one-to-many 3D video teleconferencing system
Authors: Jones Andrew , Lang Magnus , Fyffe Graham , Yu Xueming , Busch Jay , McDowall Ian , Bolas Mark , Debevec Paul
Published: July 2009

We present a set of algorithms and an associated display system capable of producing correctly rendered eye contact between a three-dimensionally transmitted remote participant and a group of observers in a 3D teleconferencing system. The participant's face is scanned in 3D at 30Hz and transmitted in real time to an autostereoscopic horizontal-parallax 3D display, displaying him or her over more than a 180° field of view observable to multiple observers. To render the geometry with correct perspective, we create a fast vertex shader based on a 6D lookup table for projecting 3D scene vertices to a range of subject angles, heights, and distances. We generalize the projection mathematics to arbitrarily shaped display surfaces, which allows us to employ a curved concave display surface to focus the high speed imagery to individual observers. To achieve two-way eye contact, we capture 2D video from a cross-polarized camera reflected to the position of the virtual participant's eyes, and display this 2D video feed on a large screen in front of the real participant, replicating the viewpoint of their virtual self. To achieve correct vertical perspective, we further leverage this image to track the position of each audience member's eyes, allowing the 3D display to render correct vertical perspective for each of the viewers around the device. The result is a one-to-many 3D teleconferencing system able to reproduce the effects of gaze, attention, and eye contact generally missing in traditional teleconferencing systems.
The UnMousePad
Authors: Rosenberg Ilya , Perlin Ken
Published: July 2009

Recently, there has been great interest in multi-touch interfaces. Such devices have taken the form of camera-based systems such as Microsoft Surface [de los Reyes et al. 2007] and Perceptive Pixel's FTIR Display [Han 2005] as well as hand-held devices using capacitive sensors such as the Apple iPhone [Jobs et al. 2008]. However, optical systems are inherently bulky while most capacitive systems are only practical in small form factors and are limited in their application since they respond only to human touch and are insensitive to variations in pressure [Westerman 1999].

We have created the UnMousePad, a flexible and inexpensive multitouch input device based on a newly developed pressure-sensing principle called Interpolating Force Sensitive Resistance. IFSR sensors can acquire high-quality anti-aliased pressure images at high frame rates. They can be paper-thin, flexible, and transparent and can easily be scaled to fit on a portable device or to cover an entire table, floor or wall. The UnMousePad can sense three orders of magnitude of pressure variation, and can be used to distinguish multiple fingertip touches while simultaneously tracking pens and styli with a positional accuracy of 87 dpi, and can sense the pressure distributions of objects placed on its surface.

In addition to supporting multi-touch interaction, IFSR is a general pressure imaging technology that can be incorporated into shoes, tennis racquets, hospital beds, factory assembly lines and many other applications. The ability to measure high-quality pressure images at low cost has the potential to dramatically improve the way that people interact with machines and the way that machines interact with the world.
Coordinates for instant image cloning
Authors: Farbman Zeev , Hoffer Gil , Lipman Yaron , Cohen-Or Daniel , Lischinski Dani
Published: July 2009

Seamless cloning of a source image patch into a target image is an important and useful image editing operation, which has received considerable research attention in recent years. This operation is typically carried out by solving a Poisson equation with Dirichlet boundary conditions, which smoothly interpolates the discrepancies between the boundary of the source patch and the target across the entire cloned area. In this paper we introduce an alternative,
coordinate-based
approach, where rather than solving a large linear system to perform the aforementioned interpolation, the value of the interpolant at each interior pixel is given by a weighted combination of values along the boundary. More specifically, our approach is based on Mean-Value Coordinates (MVC). The use of coordinates is advantageous in terms of speed, ease of implementation, small memory footprint, and parallelizability, enabling real-time cloning of large regions, and interactive cloning of video streams. We demonstrate a number of applications and extensions of the coordinate-based framework.
Interactive Hausdorff distance computation for general polygonal models
Authors: Tang Min , Lee Minkyoung , Kim Young J.
Published: July 2009

We present a simple algorithm to compute the Hausdorff distance between complicated, polygonal models at interactive rates. The algorithm requires no assumptions about the underlying topology and geometry. To avoid the high computational and implementation complexity of exact Hausdorff distance calculation, we approximate the Hausdorff distance within a user-specified error bound. The main ingredient of our approximation algorithm is a novel polygon subdivision scheme, calledVoronoi subdivision, combined with culling between the models based on bounding volume hierarchy (BVH). Thiscross-cullingmethod relies on tight yet simple computation of bounds on the Hausdorff distance, and it discards unnecessary polygon pairs from each of the input models alternatively based on the distance bounds. This algorithm can approximate the Hausdorff distance between polygonal models consisting of tens of thousands triangles with a small error bound in real-time, and outperforms the existing algorithm by more than an order of magnitude. We apply our Hausdorff distance algorithm to the measurement of shape similarity, and the computation of penetration depth for physically-based animation. In particular, the penetration depth computation using Hausdorff distance runs at highly interactive rates for complicated dynamics scene.
Interleaving Delaunay refinement and optimization for practical isotropic tetrahedron mesh generation
Authors: Tournois Jane , Wormser Camille , Alliez Pierre , Desbrun Mathieu
Published: July 2009

We present a practical approach to isotropic tetrahedral meshing of 3D domains bounded by piecewise smooth surfaces. Building upon recent theoretical and practical advances, our algorithm interleaves Delaunay refinement and mesh optimization to generate quality meshes that satisfy a set of user-defined criteria. This interleaving is shown to be more conservative in number of Steiner point insertions than refinement alone, and to produce higher quality meshes than optimization alone. A careful treatment of boundaries and their features is presented, offering a versatile framework for designing smoothly graded tetrahedral meshes.
Momentum control for balance
Authors: Macchietto Adriano , Zordan Victor , Shelton Christian R.
Published: July 2009

We demonstrate a real-time simulation system capable of automatically balancing a standing character, while at the same time tracking a reference motion and responding to external perturbations. The system is general to non-human morphologies and results in natural balancing motions employing the entire body (for example, wind-milling). Our novel balance routine seeks to control the linear and angular momenta of the character. We demonstrate how momentum is related to the center of mass and center of pressure of the character and derive control rules to change these centers for balance. The desired momentum changes are reconciled with the objective of tracking the reference motion through an optimization routine which produces target joint accelerations. A hybrid inverse/forward dynamics algorithm determines joint torques based on these joint accelerations and the ground reaction forces. Finally, the joint torques are applied to the free-standing character simulation. We demonstrate results for following both motion capture and keyframe data as well as both human and non-human morphologies in presence of a variety of conditions and disturbances.
Contact-aware nonlinear control of dynamic characters
Authors: Muico Uldarico , Lee Yongjoon , Popović Jovan , Popović Zoran
Published: July 2009

Dynamically simulated characters are difficult to control because they are underactuated---they have no direct control over their global position and orientation. In order to succeed, control policies must look ahead to determine stabilizing actions, but such planning is complicated by frequent ground contacts that produce a discontinuous search space. This paper introduces a locomotion system that generates high-quality animation of agile movements using nonlinear controllers that plan through such contact changes. We demonstrate the general applicability of this approach by emulating walking and running motions in rigid-body simulations. Then we consolidate these controllers under a higher-level planner that interactively controls the character's direction.
Local layering
Authors: McCann James , Pollard Nancy
Published: July 2009

In a conventional 2d painting or compositing program, graphical objects are stacked in a user-specified global order, as if each were printed on an image-sized sheet of transparent film. In this paper we show how to relax this restriction so that users can make stacking decisions on a per-overlap basis, as if the layers were pictures cut from a magazine. This allows for complex and visually exciting overlapping patterns, without painstaking layer-splitting, depth-value painting, region coloring, or mask-drawing. Instead, users are presented with a layers dialog which acts locally. Behind the scenes, we divide the image into overlap regions and track the ordering of layers in each region. We formalize this structure as a graph of stacking lists, define the set of orderings where layers do not interpenetrate as consistent, and prove that our local stacking operators are both correct and sufficient to reach any consistent stacking. We also provide a method for updating the local stacking when objects change shape or position due to user editing - this scheme prevents layer updates from producing undesired intersections. Our method extends trivially to both animation compositing and local visibility adjustment in depth-peeled 3d scenes; the latter of which allows for the creation of impossible figures which can be viewed and manipulated in real-time.