bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat shock proteins 27 and 70 contribute to the protection of Schisandrin B against d-galactosamine-induced liver injury in mice
Authors: Gao Zhiying , Zhang Jishun , Li Libo , Shen Longqing , Li Qingyi , Zou Yu , Du Xiaohui , Zhao Zhibo
Published: October 2015

Schisandrin B is a hepatoprotective component isolated from a traditional Chinese herb, Schisandra chinensis (Turcz.) Baill. This study determined the effect of Schisandrin B on d-galactosamine -induced liver injury and the role of heat shock proteins 27 and 70 against liver injury in mice. Acute liver injury was induced by intraperitoneal injection of d-galactosamine to mice, and Schisandrin B was given orally. The protein and gene expression of heat shock proteins 27 and 70 were detected by western blot and real-time quantitative polymerase chain reaction, respectively. Liver tissues were subjected to histological evaluation, and the activities of alanine aminotransferase and aspartate aminotransferase in the serum were measured. Pretreatment of Schisandrin B significantly attenuated d-galactosamine-induced liver injury in mice. This result was evidenced by improved alteration of histopathological hepatic necrosis and reduced alanine aminotransferase and aspartate aminotransferase activities in the serum. The hepatoprotective effect was accompanied with overexpression of heat shock proteins 27 and 70 both at the protein and mRNA levels. However, the aforementioned actions of Schisandrin B were all markedly suppressed by the heat shock protein inhibitor quercetin. Heat shock proteins 27 and 70 were involved in the protective effect of Schisandrin B against d-galactosamine-induced liver injury in mice.
An Unsupervised Online Spike-Sorting Framework
Authors: Knieling Simeon , Sridharan Kousik S. , Belardinelli Paolo , Naros Georgios , Weiss Daniel , Mormann Florian , Gharabaghi Alireza
Published: October 2015

Extracellular neuronal microelectrode recordings can include action potentials from multiple neurons. To separate spikes from different neurons, they can be sorted according to their shape, a procedure referred to as spike-sorting. Several algorithms have been reported to solve this task. However, when clustering outcomes are unsatisfactory, most of them are difficult to adjust to achieve the desired results. We present an online spike-sorting framework that uses feature normalization and weighting to maximize the distinctiveness between different spike shapes. Furthermore, multiple criteria are applied to either facilitate or prevent cluster fusion, thereby enabling experimenters to fine-tune the sorting process. We compare our method to established unsupervised offline (Wave_Clus (WC)) and online (OSort (OS)) algorithms by examining their performance in sorting various test datasets using two different scoring systems (AMI and the Adamos metric). Furthermore, we evaluate sorting capabilities on intra-operative recordings using established quality metrics. Compared to WC and OS, our algorithm achieved comparable or higher scores on average and produced more convincing sorting results for intra-operative datasets. Thus, the presented framework is suitable for both online and offline analysis and could substantially improve the quality of microelectrode-based data evaluation for research and clinical application.
Pseudo almost automorphic in distribution solutions of semilinear stochastic integro-differential equations by measure theory
Authors: Xia Zhinan
Published: October 2015

This paper deals with the [Formula: see text]-pseudo almost automorphy in distribution for a stochastic process. Under suitable conditions, we establish the existence, uniqueness of [Formula: see text]-pseudo almost automorphic in distribution mild solutions for semilinear stochastic integro-differential equations.
Cucurbitacins: A Systematic Review of the Phytochemistry and Anticancer Activity
Authors: Cai Yuee , Fang Xiefan , He Chengwei , Li Peng , Xiao Fei , Wang Yitao , Chen Meiwan
Published: October 2015

Cucurbitacins are highly oxidized tetracyclic triterpenoids that are widely present in traditional Chinese medicines (Cucurbitaceae family), possess strong anticancer activity, and are divided into 12 classes from A to T with over 200 derivatives. The eight most active cucurbitacin components against cancer are cucurbitacin B, D, E, I, IIa, L glucoside, Q, and R. Their mechanisms of action include antiproliferation, inhibition of migration and invasion, proapoptosis, and cell cycle arrest promotion. Cucurbitacins are also found to be the inhibitors of JAK-STAT3, Wnt, PI3K/Akt, and MAPK signaling pathways, which play important roles in the apoptosis and survival of cancer cells. Recently, new studies have discovered synergistic anticancer effects by using cucurbitacins together with clinically approved chemotherapeutic drugs, such as docetaxel and methotrexate. This paper provides a summary of recent research progress on the anticancer property of cucurbitacins and the various intracellular signaling pathways involved in the regulation of cancer cell proliferation, death, invasion, and migration. Therefore, cucurbitacins are a class of promising anticancer drugs to be used alone or be intergraded in current chemotherapies and radiotherapies to treat many types of cancers.
Ursolic Acid Induces Apoptosis of Prostate Cancer Cells via the PI3K/Akt/mTOR Pathway
Authors: Meng Yan , Lin Zhao-Min , Ge Nan , Zhang Deng-Lu , Huang Jie , Kong Feng
Published: October 2015

Ursolic acid (UA), a pentacyclic triterpenoid, is known to exert antitumor activity in breast, lung, liver and colon cancers. Nonetheless, the underlying mechanism of ursolic acid in prostate cancer cells still remains unclear. In the present study, we report the chemotherapeutic effects of ursolic acid as assessed using in vitro and in vivo models. Treatment of human prostate cancer cells (LNCaP and PC-3) with UA inhibited the proliferation and induced apoptosis in both cell lines as characterized by the increased Annexin V-binding. The induction of apoptosis by UA was associated with a decrease in the levels of Bcl-2, Bcl-xl, survivin, and activated caspase-3. Treatment with UA also inhibited the expression of phosphatidylinositol-3-kinase (PI3K), phosphorylation of Akt and mTOR signaling proteins. Further, administration of UA significantly inhibited the growth of LNCaP prostate tumor xenografts in athymic nude mice, which was associated with inhibition of cell proliferation, induction of apoptosis of tumor cells and decreased expression of PI3K downstream factors, such as p-Akt and p-mTOR in tumor xenograft tissues. Our study demonstrates that UA not only inhibits cell growth but also induces apoptosis through modulation of the PI3K/Akt/mTOR pathway in human prostate cancer cells. We suggest that UA may be a new chemotherapeutic candidate against prostate cancer.
Electronic, optical and thermal properties of TiCr2 and TiMn2 by ab initio simulations
Authors: Ali M. S. , Roknuzzaman M. , Parvin R. , Islam A. K. M. A. , Ostrikov K.
Published: October 2015

A theoretical study of TiX2 (X = Cr, Mn) with C14 Laves phase compounds has been performed by using the first-principles pseudopotential plane-wave method within the generalized gradient approximation (GGA). The electronic properties (Fermi surface and charge density) have been calculated and analyzed. The optical characteristics (dielectric functions, absorption spectrum, conductivity, energy-loss spectrum and reflectivity) are calculated and discussed. The calculated large positive static dielectric constant indicates good dielectric properties. The reflectivity of TiX2 (X = Cr, Mn) is high in the IR–Visible–UV region up to [Formula: see text][Formula: see text]13 eV showing promise as a good solar heating barrier material. The temperature and pressure dependence of bulk modulus, Debye temperature, specific heats and thermal expansion coefficient are obtained for T = 1200 K and P = 50 GPa through quasi-harmonic Debye model with phononic effects. Fermi surface, optical and thermodynamic properties are very important for practical applications of the materials in optical and other devices.
Group Equivariant Singularity Theory in the Bifurcation of Interfacial Wilton Ripples
Authors: Jones Mark
Published: October 2015

An investigation is made into the capillary-gravity waves which arise on the interface of two fluids and which are formed by the interaction of the first two harmonics of the motion. The problem is transformed into a nonlinear operator equation between suitable function spaces which is shown to be invariant under certain group actions. The infinite dimensional problem is reduced, by the classical procedure of Lyapunov–Schmidt, to a finite system of polynomial equations, known as the bifurcation equations. Because these equations inherit the symmetry properties of the original operator, it is possible to make quite specific statements concerning their structure, thus rendering their analysis easier. Solutions to the equations are sought, both in the cases of exact and of near-resonance. A wide variety of solutions is found depending on the values of the parameters: both simple, multiple and secondary bifurcations may occur, and in addition, there may exist isolated solution curves.
Variants of finite full transformation semigroups
Authors: Dolinka Igor , East James
Published: October 2015

The variant of a semigroup [Formula: see text] with respect to an element [Formula: see text], denoted [Formula: see text], is the semigroup with underlying set [Formula: see text] and operation ⋆ defined by [Formula: see text] for [Formula: see text]. In this paper, we study variants [Formula: see text] of the full transformation semigroup [Formula: see text] on a finite set [Formula: see text]. We explore the structure of [Formula: see text] as well as its subsemigroups [Formula: see text] (consisting of all regular elements) and [Formula: see text] (consisting of all products of idempotents), and the ideals of [Formula: see text]. Among other results, we calculate the rank and idempotent rank (if applicable) of each semigroup, and (where possible) the number of (idempotent) generating sets of the minimal possible size.
EFFECT OF SURFACE ALUMINIZING ON LONG-TERM HIGH-TEMPERATURE THERMAL STABILITY OF TC4 TITANIUM ALLOY
Authors: DAI JINGJIE , ZHU JIYUN , ZHUANG LEI , LI SHOUYING
Published: October 2015

Aluminum (Al)–rich titanium (Ti)–Al alloyed coating was fabricated on the surface of TC4 Ti alloy to improve the high-temperature stability of TC4 Ti alloy by means of arc-added glow discharge plasma technology. Microstructure, room-temperature properties and long-term high-temperature oxidation behavior of the alloyed sample were investigated. The results show that a uniform and compact Ti–Al alloyed coating with about 30[Formula: see text][Formula: see text]m thickness formed on the surface of TC4 Ti alloy. Microhardness and room-temperature wear resistance of the alloyed sample improved significantly. Long-term oxidation behaviors of the samples in air at 800[Formula: see text]C for 1000[Formula: see text]h show that the mass gain of the alloyed sample was 0.3686[Formula: see text]mg/cm2, while that of the substrate was 18.2095[Formula: see text]mg/cm2. Arc-added glow discharge plasma aluminizing improved high-temperature oxidation resistance of TC4 Ti alloy significantly.
Semi-supervised discriminant analysis method for face recognition
Authors: Chen Wen-Sheng , Dai Xiuli , Pan Binbin , Tang Yuan Yan
Published: October 2015

In face recognition (FR), a lot of algorithms just utilize one single type of facial features namely global feature or local feature, and cannot obtain better performance under the complicated variations of the facial images. To extract robust facial features, this paper proposes a novel Semi-Supervised Discriminant Analysis (SSDA) criterion via nonlinearly combining the global feature and local feature. To further enhance the discriminant power of SSDA features, the geometric distribution weight information of the training data is also incorporated into the proposed criterion. We use SSDA criterion to design an iterative algorithm which can determine the combination parameters and the optimal projection matrix automatically. Moreover, the combination parameters are guaranteed to fall into the interval [0, 1]. The proposed SSDA method is evaluated on the ORL, FERET and CMU PIE face databases. The experimental results demonstrate that our method achieves superior performance.
Fractal analysis and control of the competition model
Authors: Zhang Mianmian , Zhang Yongping
Published: October 2015

Lotka–Volterra population competition model plays an important role in mathematical models. In this paper, Julia set of the competition model is introduced by use of the ideas and methods of Julia set in fractal geometry. Then feedback control is taken on the Julia set of the model. And synchronization of two different Julia sets of the model with different parameters is discussed, which makes one Julia set change to be another. The simulation results show the efficacy of these methods.
Global dynamics of two heterogeneous SIR models with nonlinear incidence and delays
Authors: Song Haitao , Jiang Weihua , Liu Shengqiang
Published: October 2015

To investigate the effect of heterogeneity on the global dynamics of two SIR epidemic models with general nonlinear incidence rate and infection delays, we formulate a multi-group model corresponding to the heterogeneity in the host population and a multi-stage model corresponding to heterogeneous stages of infection. Under biologically motivated considerations, we establish that the global dynamics for each of the two models is determined completely by the corresponding basic reproduction number: if the basic reproduction number is less than or equal to one, then the disease-free equilibrium is globally asymptotically stable and the disease dies out in all groups or stages; if the basic reproduction number is larger than one, then the disease will persist in all groups or stages, and there is a unique endemic equilibrium which is globally asymptotically stable. Then we conclude that the heterogeneity does not change the global dynamics of the SIR model when the incidence rate is a general nonlinear function. Our results extend a class of previous results and can be applied to the other epidemiological models. The proofs of the main results use Lyapunov functional and graph-theoretic approach.
Multiscale models of compact bone
Authors: Li Junfeng , Li Shugang
Published: October 2015

This work is concerned about multiscale models of compact bone. We focus on the lacuna–canalicular system. The interstitial fluid and the ions in it are regarded as solvent and others are treated as solute. The system has the characteristic of solvation process as well as non-equilibrium dynamics. The differential geometry theory of surfaces is adopted. We use this theory to separate the macroscopic domain of solvent from the microscopic domain of solute. We also use it to couple continuum and discrete descriptions. The energy functionals are constructed and then the variational principle is applied to the energy functionals so as to derive desirable governing equations. We consider both long-range polar interactions and short-range nonpolar interactions. The solution of governing equations leads to the minimization of the total energy.
Induced operators on the space of homogeneous polynomials
Authors: Zamani Yousef , Ranjbari Mahin
Published: October 2015

Let [Formula: see text] be the complex vector space of homogeneous polynomials of degree [Formula: see text] with the independent variables [Formula: see text]. Let [Formula: see text] be the complex vector space of homogeneous linear polynomials in the variables [Formula: see text]. For any linear operator [Formula: see text] acting on [Formula: see text], there is a (unique) induced operator [Formula: see text] acting on [Formula: see text] satisfying [Formula: see text] In this paper, we study some algebraic and geometric properties of induced operator [Formula: see text]. Also, we obtain the norm of the derivative of the map [Formula: see text] in terms of the norm of [Formula: see text].
Formation Characteristics of Propane Hydrate Using Fiber Layer
Authors: Kumano Hiroyuki , Asaoka Tatsunori , Sugaya Kento , Mochizuki Yuta , Okada Masashi
Published: October 2015

Formation characteristics of propane hydrate using fiber layer were investigated experimentally. Water and propane gas contact in the fiber layer, and the propane gas hydrate can be formed continuously. In the experiment, pressure, temperature, the quantity of water and porosity of the fiber layer were varied as the experimental parameters, and the formation ratio and the formation rate were measured. As a result, it was found that the high formation ratio can be obtained by using the fiber layer. Therefore, it can be said that this method is useful to reduce energy consumption and to simplify the apparatus, since it does not need circulation system. Moreover, it was found that the formation rate increases with the subcooling and the quantity of water, and it is slightly affected by the porosity of the fiber layer.
Portable X-ray fluorescence measurements on exploration drill-cores: comparing performance on unprepared cores and powders for ‘whole-rock’ analysis
Authors: Bourke A. , Ross P.-S.
Published: October 2015

One geoscience application of portable XRF (pXRF) technology is acquiring ‘whole-rock’ analyses of unmineralized or weakly mineralized rock cores for major oxides and trace elements, to fill the gaps between traditional laboratory analyses and/or obtain geochemical data more quickly. But the question of whether the samples actually need to be crushed and pulverized before analysis to produce useful results has not been extensively studied. In this paper pXRF data quality is compared on unprepared rock cores and on powders in three ways: instrumental precision (relative standard deviation [RSD] of a series of measurements on the same spot), sample precision (for unprepared samples, RSD of a series of measurements on different spots on the core), and accuracy (average pXRF value versus laboratory geochemistry). Two Olympus Innov-X Delta Premium pXRF devices were tested on 27 core samples of dense, non-mineralized, fine- to medium-grained, Precambrian volcanic and intrusive rocks from Canada. In general, sample preparation does not improve instrumental precision or accuracy. The significant advantage of powders is to avoid mineralogical heterogeneity. However, sample precision for
in situ
data is improved by averaging multiple measurements of different points on the sample: a significant gain is obtained between three and seven measurements. The sample precisions at 25 points – which is about the most measurements one can make during the same amount of time used for powdering a rock core sample – are better than the instrumental precision on powders for most elements. For high spatial resolution down-hole element profiles on entire drill-holes,
in situ
pXRF measurements with smoothing (e.g. 3–5 point moving averages) provide fit-for-purpose data; the alternative of turning the entire drill-core into powder is not realistic.
Optimizing Sparse Matrix—Matrix Multiplication for the GPU
Authors: Dalton Steven , Olson Luke , Bell Nathan
Published: October 2015

Sparse matrix--matrix multiplication (SpGEMM) is a key operation in numerous areas from information to the physical sciences. Implementing SpGEMM efficiently on throughput-oriented processors, such as the graphics processing unit (GPU), requires the programmer to expose substantial fine-grained parallelism while conserving the limited off-chip memory bandwidth. Balancing these concerns, we decompose the SpGEMM operation into three highly parallel phases: expansion, sorting, and contraction, and introduce a set of complementary bandwidth-saving performance optimizations. Our implementation is fully general and our optimization strategy adaptively processes the SpGEMM workload row-wise to substantially improve performance by decreasing the work complexity and utilizing the memory hierarchy more effectively.
Recommending Users and Communities in Social Media
Authors: Li Lei , Peng Wei , Kataria Saurabh , Sun Tong , Li Tao
Published: October 2015

Social media has become increasingly prevalent in the last few years, not only enabling people to connect with each other by social links, but also providing platforms for people to share information and interact over diverse topics. Rich user-generated information, for example, users’ relationships and daily posts, are often available in most social media service websites. Given such information, a challenging problem is to provide reasonable user and community recommendation for a target user, and consequently, help the target user engage in the daily discussions and activities with his/her friends or like-minded people. In this article, we propose a unified framework of recommending users and communities that utilizes the information in social media. Given a user’s profile or a set of keywords as input, our framework is capable of recommending influential users and topic-cohesive interactive communities that are most relevant to the given user or keywords. With the proposed framework, users can find other individuals or communities sharing similar interests, and then have more interaction with these users or within the communities. We present a generative topic model to discover user-oriented and community-oriented topics simultaneously, which enables us to capture the exact topical interests of users, as well as the focuses of communities. Extensive experimental evaluation and case studies on a dataset collected from Twitter demonstrate the effectiveness of our proposed framework compared with other probabilistic-topic-model-based recommendation methods.
Real-time expression transfer for facial reenactment
Authors: Thies Justus , Zollhöfer Michael , Nießner Matthias , Valgaerts Levi , Stamminger Marc , Theobalt Christian
Published: October 2015

We present a method for the real-time transfer of facial expressions from an actor in a source video to an actor in a target video, thus enabling the ad-hoc control of the facial expressions of the target actor. The novelty of our approach lies in the transfer and photorealistic re-rendering of facial deformations and detail into the target video in a way that the newly-synthesized expressions are virtually indistinguishable from a real video. To achieve this, we accurately capture the facial performances of the source and target subjects in real-time using a commodity RGB-D sensor. For each frame, we jointly fit a parametric model for identity, expression, and skin reflectance to the input color and depth data, and also reconstruct the scene lighting. For expression transfer, we compute the difference between the source and target expressions in parameter space, and modify the target parameters to match the source expressions. A major challenge is the convincing re-rendering of the synthesized target face into the corresponding video stream. This requires a careful consideration of the lighting and shading design, which both must correspond to the real-world environment. We demonstrate our method in a live setup, where we modify a video conference feed such that the facial expressions of a different person (e.g., translator) are matched in real-time.
Activity-centric scene synthesis for functional 3D scene modeling
Authors: Fisher Matthew , Savva Manolis , Li Yangyan , Hanrahan Pat , Nießner Matthias
Published: October 2015

We present a novel method to generate 3D scenes that allow the same activities as real environments captured through noisy and incomplete 3D scans. As robust object detection and instance retrieval from low-quality depth data is challenging, our algorithm aims to model semantically-correct rather than geometrically-accurate object arrangements. Our core contribution is a new scene synthesis technique which, conditioned on a coarse geometric scene representation, models functionally similar scenes using prior knowledge learned from a scene database. The key insight underlying our scene synthesis approach is that many real-world environments are structured to facilitate specific human activities, such as sleeping or eating. We represent scene functionalities through virtual agents that associate object arrangements with the activities for which they are typically used. When modeling a scene, we first identify the activities supported by a scanned environment. We then determine semantically-plausible arrangements of virtual objects -- retrieved from a shape database -- constrained by the observed scene geometry. For a given 3D scan, our algorithm produces a variety of synthesized scenes which support the activities of the captured real environments. In a perceptual evaluation study, we demonstrate that our results are judged to be visually appealing and functionally comparable to manually designed scenes.
AutoConnect
Authors: Koyama Yuki , Sueda Shinjiro , Steinhardt Emma , Igarashi Takeo , Shamir Ariel , Matusik Wojciech
Published: October 2015

We present AutoConnect, an automatic method that creates customized, 3D-printable connectors attaching two physical objects together. Users simply position and orient virtual models of the two objects that they want to connect and indicate some auxiliary information such as weight and dimensions. Then, AutoConnect creates several alternative designs that users can choose from for 3D printing. The design of the connector is created by combining two holders, one for each object. We categorize the holders into two types. The first type holds standard objects such as pipes and planes. We utilize a database of parameterized mechanical holders and optimize the holder shape based on the grip strength and material consumption. The second type holds free-form objects. These are procedurally generated shell-gripper designs created based on geometric analysis of the object. We illustrate the use of our method by demonstrating many examples of connectors and practical use cases.
Unsynchronized structured light
Authors: Moreno Daniel , Calakli Fatih , Taubin Gabriel
Published: October 2015

Various Structured Light (SL) methods are used to capture 3D range images, where a number of binary or continuous light patterns are sequentially projected onto a scene of interest, while a digital camera captures images of the illuminated scene. All existing SL methods require the projector and camera to be hardware or software synchronized, with one image captured per projected pattern. A 3D range image is computed from the captured images. The two synchronization methods have disadvantages, which limit the use of SL methods to niche industrial and low quality consumer applications. Unsynchronized Structured Light (USL) is a novel SL method which does not require synchronization of pattern projection and image capture. The light patterns are projected and the images are captured independently, at constant, but possibly different, frame rates. USL synthesizes new binary images as would be decoded from the images captured by a camera synchronized to the projector, reducing the subsequent computation to standard SL. USL works both with global and rolling shutter cameras. USL enables most burst-mode-capable cameras, such as modern smartphones, tablets, DSLRs, and point-and-shoots, to function as high quality 3D snapshot cameras. Beyond the software, which can run in the devices, a separate SL Flash, able to project the sequence of patterns cyclically, during the acquisition time, is needed to enable the functionality.
A unified approach for subspace simulation of deformable bodies in multiple domains
Authors: Wu Xiaofeng , Mukherjee Rajaditya , Wang Huamin
Published: October 2015

Multi-domain subspace simulation can efficiently and conveniently simulate the deformation of a large deformable body, by constraining the deformation of each domain into a different subspace. The key challenge in implementing this method is how to handle the coupling among multiple deformable domains, so that the overall effect is free of gap or locking issues. In this paper, we present a new domain decomposition framework that connects two disjoint domains through coupling elements. Under this framework, we present a unified simulation system that solves subspace deformations and rigid motions of all of the domains by a single linear solve. Since the coupling elements are part of the deformable body, their elastic properties are the same as the rest of the body and our system does not need stiffness parameter tuning. To quickly evaluate the reduced elastic forces and their Jacobian matrices caused by the coupling elements, we further develop two cubature optimization schemes using uniform and non-uniform cubature weights. Our experiment shows that the whole system can efficiently handle large and complex scenes, many of which cannot be easily simulated by previous techniques without limitations.
Wetbrush
Authors: Chen Zhili , Kim Byungmoon , Ito Daichi , Wang Huamin
Published: October 2015

We present a real-time painting system that simulates the interactions among brush, paint, and canvas at the bristle level. The key challenge is how to model and simulate sub-pixel paint details, given the limited computational resource in each time step. To achieve this goal, we propose to define paint liquid in a hybrid fashion: the liquid close to the brush is modeled by particles, and the liquid away from the brush is modeled by a density field. Based on this representation, we develop a variety of techniques to ensure the performance and robustness of our simulator under large time steps, including brush and particle simulations in non-inertial frames, a fixed-point method for accelerating Jacobi iterations, and a new Eulerian-Lagrangian approach for simulating detailed liquid effects. The resulting system can realistically simulate not only the motions of brush bristles and paint liquid, but also the liquid transfer processes among different representations. We implement the whole system on GPU by CUDA. Our experiment shows that artists can use the system to draw realistic and vivid digital paintings, by applying the painting techniques that they are familiar with but not offered by many existing systems.
Adaptive color display via perceptually-driven factored spectral projection
Authors: Kauvar Isaac , Yang Samuel J. , Shi Liang , McDowall Ian , Wetzstein Gordon
Published: October 2015

Fundamental display characteristics are constantly being improved, especially resolution, dynamic range, and color reproduction. However, whereas high resolution and high-dynamic range displays have matured as a technology, it remains largely unclear how to extend the color gamut of a display without either sacrificing light throughput or making other tradeoffs. In this paper, we advocate for adaptive color display; with hardware implementations that allow for color primaries to be dynamically chosen, an optimal gamut and corresponding pixel states can be computed in a content-adaptive and user-centric manner. We build a flexible gamut projector and develop a perceptually-driven optimization framework that robustly factors a wide color gamut target image into a set of time-multiplexed primaries and corresponding pixel values. We demonstrate that adaptive primary selection has many benefits over fixed gamut selection and show that our algorithm for joint primary selection and gamut mapping performs better than existing methods. Finally, we evaluate the proposed computational display system extensively in simulation and, via photographs and user experiments, with a prototype adaptive color projector.
Joint embeddings of shapes and images via CNN image purification
Authors: Li Yangyan , Su Hao , Qi Charles Ruizhongtai , Fish Noa , Cohen-Or Daniel , Guibas Leonidas J.
Published: October 2015

Both 3D models and 2D images contain a wealth of information about everyday objects in our environment. However, it is difficult to semantically link together these two media forms, even when they feature identical or very similar objects. We propose a
joint
embedding space populated by both 3D shapes and 2D images of objects, where the distances between embedded entities reflect similarity between the underlying objects. This joint embedding space facilitates comparison between entities of either form, and allows for cross-modality retrieval. We construct the embedding space using 3D shape similarity measure, as 3D shapes are more pure and complete than their appearance in images, leading to more robust distance metrics. We then employ a Convolutional Neural Network (CNN) to "purify" images by muting distracting factors. The CNN is trained to map an image to a point in the embedding space, so that it is close to a point attributed to a 3D model of a similar object to the one depicted in the image. This purifying capability of the CNN is accomplished with the help of a large amount of training data consisting of images synthesized from 3D shapes. Our joint embedding allows cross-view image retrieval, image-based shape retrieval, as well as shape-based image retrieval. We evaluate our method on these retrieval tasks and show that it consistently out-performs state-of-the-art methods, and demonstrate the usability of a joint embedding in a number of additional applications.
Capturing the human figure through a wall
Authors: Adib Fadel , Hsu Chen-Yu , Mao Hongzi , Katabi Dina , Durand Frédo
Published: October 2015

We present RF-Capture, a system that captures the human figure -- i.e., a coarse skeleton -- through a wall. RF-Capture tracks the 3D positions of a person's limbs and body parts even when the person is fully occluded from its sensor, and does so without placing any markers on the subject's body. In designing RF-Capture, we built on recent advances in wireless research, which have shown that certain radio frequency (RF) signals can traverse walls and reflect off the human body, allowing for the detection of human motion through walls. In contrast to these past systems which abstract the entire human body as a single point and find the overall location of that point through walls, we show how we can reconstruct various human body parts and stitch them together to capture the human figure. We built a prototype of RF-Capture and tested it on 15 subjects. Our results show that the system can capture a representative human figure through walls and use it to distinguish between various users.
Generalized cylinder decomposition
Authors: Zhou Yang , Yin Kangxue , Huang Hui , Zhang Hao , Gong Minglun , Cohen-Or Daniel
Published: October 2015

Decomposing a complex shape into geometrically simple primitives is a fundamental problem in geometry processing. We are interested in a shape decomposition problem where the simple primitives sought are
generalized cylinders
, which are ubiquitous in both organic forms and man-made artifacts. We introduce a quantitative measure of
cylindricity
for a shape part and develop a cylindricity-driven optimization algorithm, with a global objective function, for
generalized cylinder decomposition.
As a measure of geometric simplicity and following the minimum description length principle, cylindricity is defined as the cost of representing a cylinder through skeletal and cross-section profile curves. Our decomposition algorithm progressively builds local to non-local cylinders, which form over-complete covers of the input shape. The over-completeness of the cylinder covers ensures a conservative buildup of the cylindrical parts, leaving the final decision on decomposition to global optimization. We solve the global optimization by finding an exact cover, which optimizes the global objective function. We demonstrate results of our optimal decomposition algorithm on numerous examples and compare with other alternatives.
Autoscanning for coupled scene reconstruction and proactive object analysis
Authors: Xu Kai , Huang Hui , Shi Yifei , Li Hao , Long Pinxin , Caichen Jianong , Sun Wei , Chen Baoquan
Published: October 2015

Detailed scanning of indoor scenes is tedious for humans. We propose autonomous scene scanning by a robot to relieve humans from such a laborious task. In an autonomous setting, detailed scene acquisition is inevitably
coupled
with scene analysis at the required level of detail. We develop a framework for object-level scene reconstruction coupled with object-centric scene analysis. As a result, the autoscanning and reconstruction will be
object-aware
, guided by the object analysis. The analysis is, in turn, gradually improved with progressively increased object-wise data fidelity. In realizing such a framework, we drive the robot to execute an iterative
analyze-and-validate
algorithm which interleaves between object analysis and guided validations.

The object analysis incorporates online learning into a robust graph-cut based segmentation framework, achieving a global update of object-level segmentation based on the knowledge gained from robot-operated local validation. Based on the current analysis, the robot performs
proactive
validation over the scene with physical push and scan refinement, aiming at reducing the uncertainty of both object-level segmentation and object-wise reconstruction. We propose a joint entropy to measure such uncertainty based on segmentation confidence and reconstruction quality, and formulate the selection of validation actions as a maximum information gain problem. The output of our system is a reconstructed scene with both object extraction and object-wise geometry fidelity.
Efficient construction and simplification of Delaunay meshes
Authors: Liu Yong-Jin , Xu Chun-Xu , Fan Dian , He Ying
Published: October 2015

Delaunay meshes (DM) are a special type of triangle mesh where the local Delaunay condition holds everywhere. We present an efficient algorithm to convert an arbitrary manifold triangle mesh
M
into a Delaunay mesh. We show that the constructed DM has
O
(
Kn
) vertices, where
n
is the number of vertices in
M
and
K
is a model-dependent constant. We also develop a novel algorithm to simplify Delaunay meshes, allowing a smooth choice of detail levels. Our methods are conceptually simple, theoretically sound and easy to implement. The DM construction algorithm also scales well due to its
O
(
nK
log
K
) time complexity.

Delaunay meshes have many favorable geometric and numerical properties. For example, a DM has exactly the same geometry as the input mesh, and it can be encoded by any mesh data structure. Moreover, the empty geodesic circumcircle property implies that the commonly used cotangent Laplace-Beltrami operator has non-negative weights. Therefore, the existing digital geometry processing algorithms can benefit the numerical stability of DM without changing any codes. We observe that DMs can improve the accuracy of the heat method for computing geodesic distances. Also, popular parameterization techniques, such as discrete harmonic mapping, produce more stable results on the DMs than on the input meshes.
Instant field-aligned meshes
Authors: Jakob Wenzel , Tarini Marco , Panozzo Daniele , Sorkine-Hornung Olga
Published: October 2015

We present a novel approach to remesh a surface into an isotropic triangular or quad-dominant mesh using a unified local smoothing operator that optimizes both the edge orientations and vertex positions in the output mesh. Our algorithm produces meshes with high isotropy while naturally aligning and snapping edges to sharp features. The method is simple to implement and parallelize, and it can process a variety of input surface representations, such as point clouds, range scans and triangle meshes. Our full pipeline executes instantly (less than a second) on meshes with hundreds of thousands of faces, enabling new types of interactive workflows. Since our algorithm avoids any global optimization, and its key steps scale linearly with input size, we are able to process extremely large meshes and point clouds, with sizes exceeding several hundred million elements. To demonstrate the robustness and effectiveness of our method, we apply it to hundreds of models of varying complexity and provide our cross-platform reference implementation in the supplemental material.
Autocomplete hand-drawn animations
Authors: Xing Jun , Wei Li-Yi , Shiratori Takaaki , Yatani Koji
Published: October 2015

Hand-drawn animation is a major art form and communication medium, but can be challenging to produce. We present a system to help people create frame-by-frame animations through manual sketches. We design our interface to be minimalistic: it contains only a canvas and a few controls. When users draw on the canvas, our system silently analyzes all past sketches and predicts what might be drawn in the future across spatial locations and temporal frames. The interface also offers suggestions to beautify existing drawings. Our system can reduce manual workload and improve output quality without compromising natural drawing flow and control: users can accept, ignore, or modify such predictions visualized on the canvas by simple gestures. Our key idea is to extend the local similarity method in [Xing et al. 2014], which handles only low-level spatial repetitions such as hatches within a single frame, to a global similarity that can capture high-level structures across multiple frames such as dynamic objects. We evaluate our system through a preliminary user study and confirm that it can enhance both users' objective performance and subjective satisfaction.
Physically-accurate fur reflectance
Authors: Yan Ling-Qi , Tseng Chi-Wei , Jensen Henrik Wann , Ramamoorthi Ravi
Published: October 2015

Rendering photo-realistic animal fur is a long-standing problem in computer graphics. Considerable effort has been made on modeling the geometric complexity of fur, but the reflectance of fur fibers is not well understood. Fur has a distinct diffusive and saturated appearance, that is not captured by either the Marschner hair model or the Kajiya-Kay model. In this paper, we develop a physically-accurate reflectance model for fur fibers. Based on anatomical literature and measurements, we develop a double cylinder model for the reflectance of a single fur fiber, where an outer cylinder represents the biological observation of a cortex covered by multiple cuticle layers, and an inner cylinder represents the scattering interior structure known as the medulla. Our key contribution is to model medulla scattering accurately---in contrast, for human hair, the medulla has minimal width and thus negligible contributions to the reflectance. Medulla scattering introduces additional reflection and transmission paths, as well as diffusive reflectance lobes. We validate our physical model with measurements on real fur fibers, and introduce the first database in computer graphics of reflectance profiles for nine fur samples. We show that our model achieves significantly better fits to the measured data than the Marschner hair reflectance model. For efficient rendering, we develop a method to precompute 2D medulla scattering profiles and analytically approximate our reflectance model with factored lobes. The accuracy of the approach is validated by comparing our rendering model to full 3D light transport simulations. Our model provides an enriched set of controls, where the parameters we fit can be directly used to render realistic fur, or serve as a starting point from which artists can manually tune parameters for desired appearances.
Smoothed aggregation multigrid for cloth simulation
Authors: Tamstorf Rasmus , Jones Toby , McCormick Stephen F.
Published: October 2015

Existing multigrid methods for cloth simulation are based on geometric multigrid. While good results have been reported, geometric methods are problematic for unstructured grids, widely varying material properties, and varying anisotropies, and they often have difficulty handling constraints arising from collisions. This paper applies the algebraic multigrid method known as
smoothed aggregation
to cloth simulation. This method is agnostic to the underlying tessellation, which can even vary over time, and it only requires the user to provide a fine-level mesh. To handle contact constraints efficiently, a
prefiltered preconditioned conjugate gradient
method is introduced. For highly efficient preconditioners, like the ones proposed here, prefiltering is essential, but, even for simple preconditioners, prefiltering provides significant benefits in the presence of many constraints. Numerical tests of the new approach on a range of examples confirm 6--8
x
speedups on a fully dressed character with 371k vertices, and even larger speedups on synthetic examples.
Generalizing wave gestures from sparse examples for real-time character control
Authors: Rhodin Helge , Tompkin James , Kim Kwang In , de Aguiar Edilson , Pfister Hanspeter , Seidel Hans-Peter , Theobalt Christian
Published: October 2015

Motion-tracked real-time character control is important for games and VR, but current solutions are limited: retargeting is hard for non-human characters, with locomotion bound to the sensing volume; and pose mappings are ambiguous with difficult dynamic motion control. We robustly estimate wave properties ---
amplitude, frequency, and phase
---for a set of interactively-defined gestures by mapping user motions to a low-dimensional independent representation. The mapping separates simultaneous or intersecting gestures, and extrapolates gesture variations from single training examples. For animations such as locomotion, wave properties map naturally to stride length, step frequency, and progression, and allow smooth transitions from standing, to walking, to running. Interpolating out-of-phase locomotions is hard, e.g., quadruped legs between walks and runs switch phase, so we introduce a new time-interpolation scheme to reduce artifacts. These improvements to real-time motion-tracked character control are important for common cyclic animations. We validate this in a user study, and show versatility to apply to part- and full-body motions across a variety of sensors.
Anisotropic Gaussian mutations for metropolis light transport through Hessian-Hamiltonian dynamics
Authors: Li Tzu-Mao , Lehtinen Jaakko , Ramamoorthi Ravi , Jakob Wenzel , Durand Frédo
Published: October 2015

The simulation of light transport in the presence of multi-bounce glossy effects and motion is challenging because the integrand is high dimensional and areas of high-contribution tend to be narrow and hard to sample. We present a Markov Chain Monte Carlo (MCMC) rendering algorithm that extends Metropolis Light Transport by automatically and explicitly adapting to the local shape of the integrand, thereby increasing the acceptance rate. Our algorithm characterizes the local behavior of throughput in path space using its gradient as well as its Hessian. In particular, the Hessian is able to capture the strong anisotropy of the integrand. We obtain the derivatives using automatic differentiation, which makes our solution general and easy to extend to additional sampling dimensions such as time.

However, the resulting second order Taylor expansion is not a proper distribution and cannot be used directly for importance sampling. Instead, we use ideas from Hamiltonian Monte-Carlo and simulate the Hamiltonian dynamics in a flipped version of the Taylor expansion where gravity pulls particles towards the high-contribution region. Whereas such methods usually require numerical integration, we show that our quadratic landscape leads to a closed-form anisotropic Gaussian distribution for the final particle positions, and it results in a standard Metropolis-Hastings algorithm. Our method excels at rendering glossy-to-glossy reflections on small and highly curved surfaces. Furthermore, unlike previous work that derives sampling anisotropy with pen and paper and only considers specific effects such as specular BSDFs, we characterize the local shape of throughput through automatic differentiation. This makes our approach very general. In particular, our method is the first MCMC rendering algorithm that is able to resolve the anisotropy in the time dimension and render difficult moving caustics.