We propose a novel online manifold regularization framework based on the notion of duality in constrained optimization. The Fenchel conjugate of hinge functions is a key to transfer manifold regularization from offlin...
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We propose a novel online manifold regularization framework based on the notion of duality in constrained optimization. The Fenchel conjugate of hinge functions is a key to transfer manifold regularization from offline to online in this paper. Our algorithms are derived by gradient ascent in the dual function. For practical purpose, we propose two buffering strategies and two sparse approximations to reduce the computational complexity. Detailed experiments verify the utility of our approaches. An important conclusion is that our online MR algorithms can handle the settings where the target hypothesis is not fixed but drifts with the sequence of examples. We also recap and draw connections to earlier works. This paper paves a way to the design and analysis of online manifold regularization algorithms.
The problem of reconstruction of inclusions in rough diamonds occupies an important place in the entire technological process of extraction and cutting precious stones. Inclusions are foreign objects that are naturall...
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The problem of reconstruction of inclusions in rough diamonds occupies an important place in the entire technological process of extraction and cutting precious stones. Inclusions are foreign objects that are naturally formed in raw stock during the formation of diamond (see Fig. 1). The algorithm proposed in the present paper performs a full reconstruction of three-dimensional models of inclusions from photo images. Three-dimensional models of inclusions are based on a voxel representation. The algorithm performs the coloring of voxels and the segmentation of a voxel grid and constructs polygonal models of inclusions. Experiments carried out on real and synthetic data show that the algorithm can reconstruct three-dimensional models of medium- and large-size inclusions, which may serve as a first approximation for the methods of refinement of the shape of inclusions.
This paper takes the electric off-road vehicle with separated driven axles as the research object. To solve the longitudinal dynamics driving control problems, vehicle dynamics model, and control strategies were studi...
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This paper takes the electric off-road vehicle with separated driven axles as the research object. To solve the longitudinal dynamics driving control problems, vehicle dynamics model, and control strategies were studied and the corresponding simulation was carried out. An 8-DOF vehicle dynamics model with separated driven axles was built. The driving control strategies on the typical roads were put forward. The recognition algorithm of the typical road surfaces based on the wheels' slip rates was proposed. And the two control systems were designed including the pedal opening degree adjustment control system based on PI algorithm and the interaxle torque distribution control system based on sliding mode control algorithm. The driving control flow of the proposed vehicle combining the pedal adjustment control system with the interaxle torque distribution control system was developed. And the driven control strategies for the typical roads were simulated. Simulation results show that the proposed drive control strategies can adapt to different typical road surfaces, limit the slip rates of the driving wheels within the stable zone, and ensure the vehicle driving safely and stably in accordance with the driver's intention.
A simple program for constructing a cellular self-reproducing rectangular loop of arbitrary size is developed based on the parallel substitution algorithm (PSA), which provides a spatial model for representing fine-gr...
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A simple program for constructing a cellular self-reproducing rectangular loop of arbitrary size is developed based on the parallel substitution algorithm (PSA), which provides a spatial model for representing fine-grained parallel computations. In order to launch the self-reproduction of a loop of some specified size, one should enter its description into the input tape. The program includes operators for preliminary cleaning the cellular array, which makes it possible to easily change its internal functional structure. Two variants of the program are developed. The first variant constructs a chain of self-reproducing loops of the given size, and the second variant constructs an array of such loops.
We present a user-level thread scheduler for shared-memory multiprocessors, and we analyze its performance under multiprogramming. We model multiprogramming with two scheduling levels: our scheduler runs at user-level...
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We present a user-level thread scheduler for shared-memory multiprocessors, and we analyze its performance under multiprogramming. We model multiprogramming with two scheduling levels: our scheduler runs at user-level and schedules threads onto a fixed collection of processes, while below this level, the operating system kernel schedules processes onto a fixed collection of processors. We consider the kernel to be an adversary, and our goal is to schedule threads onto processes such that we make efficient use of whatever processor resources are provided by the kernel. Our thread scheduler is a non-blocking implementation of the work-stealing algorithm. For any multithreaded computation with work T-1 and critical-path length T-infinity, and for any number P of processes, our scheduler executes the computation in expected time O(T-1 / P-A + T-infinity P / P-A), where P-A is the average number of processors allocated to the computation by the kernel. This time bound is optimal to within a constant factor, and achieves linear speedup whenever P is small relative to the parallelism T-1/T-infinity.
The Point-Based Global Illumination (PBGI) algorithm is composed of two major steps: a caching step and a multiview rasterization step. At caching time, a dense point-sampling of the scene is shaded and organized in a...
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The Point-Based Global Illumination (PBGI) algorithm is composed of two major steps: a caching step and a multiview rasterization step. At caching time, a dense point-sampling of the scene is shaded and organized in a spatial hierarchy, with internal nodes approximating the radiance of their subtrees using spherical harmonics. At rasterization time, a microbuffer is instantiated at the unprojected position of each image pixel (receiver). Then, a view-adaptive level-of-detail of the scene is extracted in the form of a tree cut and rasterized in the receiver's microbuffer, solving for visibility using a local variant of the z-buffer. Finally, the pixel color is computed by convolving its filled microbuffer with the surface BRDF. This noise-free indirect lighting method is widely used in the industry and captures several critical lighting effects, including ambient occlusion, color bleeding, (indirect) soft-shadows and environment lighting. However, we observe a large redundancy in this algorithm, both in cuts and receivers'microbuffers, which stems from their relatively low resolution. In this paper, we propose an evolution of PBGI which exploits spatial coherence to reduce these redundant computations. Starting from a similarity-based variational clustering of the receivers, we compute a single tree cut and rasterize a single microbuffer for each cluster. This per-cluster microbuffer provides a faithful approximation of the incident radiance for distant nodes and is composited over a receiver-specific microbuffer rasterizing only the closest nodes of the cluster's cut. This factorized approach is easy to integrate in any existing PBGI implementation and offers a significant rendering speed-up for a negligible and controllable approximation error.
This paper proposes an online maximum efficiency tracking control for a dual-motor drive system. The efficiency of each drive system is obtained by online measuring the input power and online estimating the output pow...
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This paper proposes an online maximum efficiency tracking control for a dual-motor drive system. The efficiency of each drive system is obtained by online measuring the input power and online estimating the output power. Two algorithms, including the steepest ascent algorithm and fuzzy logic algorithm are proposed to achieve maximum efficiency tracking. The proposed methods do not require any computations related to the copper and core losses of the motor and the switching and conduction losses of the inverter. In addition, the proposed drive system can have better efficiency and better flexibility and requires smaller power ratings of each motor and inverter, which are easily manufactured in industry. The control algorithms are executed by using two digital signal processors, type TMS 320-F2808, made by Texas Instruments Incorporated Company. A controller area network (CAN) bus is used as a communication tool. Several experimental results show the correctness and feasibility of the proposed method. The proposed method can be easily applied in industry because of its simplicity.
Based on the backstepping method, this paper proposes a robust control algorithm for nonlinear plants under parametric uncertainty and external bounded disturbances. The algorithm ensures tracking of the plant output ...
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Based on the backstepping method, this paper proposes a robust control algorithm for nonlinear plants under parametric uncertainty and external bounded disturbances. The algorithm ensures tracking of the plant output to a smooth reference signal with a required accuracy in the steady-state mode. In comparison with the existing analogs, control system implementation requires only one filter of dimension coinciding with the plant relative degree and observers used for calculation of the stabilizing and basic control laws. This feature considerably simplifies the control scheme and calculation of its parameters. And finally, simulation results illustrating the performance of this scheme are given.
We present five new cloud detection algorithms over land based on dynamic threshold or Bayesian techniques, applicable to the Advanced Along-Track Scanning Radiometer (AATSR) instrument and compare these to the standa...
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We present five new cloud detection algorithms over land based on dynamic threshold or Bayesian techniques, applicable to the Advanced Along-Track Scanning Radiometer (AATSR) instrument and compare these to the standard threshold-based SADIST cloud detection scheme. We use a manually classified dataset as a reference to assess algorithm performance and quantify the impact of each cloud detection scheme on land-surface temperature (LST) retrieval. The use of probabilistic Bayesian cloud detection methods improves algorithm true skill scores by 8-9% over SADIST (maximum score of 77.93% compared with 69.27%). We present an assessment of the impact of imperfect cloud masking, in relation to the reference cloud mask, on the retrieved AATSR LST imposing a 2K tolerance over a 3x3 pixel domain. We find an increase of 5-7% in the observations falling within this tolerance when using Bayesian methods (maximum of 92.02% compared with 85.69%). We also demonstrate that the use of dynamic thresholds in the tests employed by SADIST can significantly improve performance, applicable to cloud-test data to be provided by the Sea and Land Surface Temperature Radiometer (SLSTR) due to be launched on the Sentinel 3 mission (estimated 2014).
This paper presents a new distributed method for virtual Earth terrain tessellation on a graphics processing unit (GPU) for space simulator complexes. The method operates in real time in multi-object virtual scenes co...
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This paper presents a new distributed method for virtual Earth terrain tessellation on a graphics processing unit (GPU) for space simulator complexes. The method operates in real time in multi-object virtual scenes comprising up to two million polygons. A polygonal terrain model is constructed using triangle patches of different levels of detail on graphics cards with programmable tessellation. Patches of the same level of detail are calculated entirely on the GPU, in parallel and independently, by using a developed shader program written in the OpenGL Shading Language (GLSL). This paper also describes a patch extraction algorithm for visible Earth surface rendering and an algorithm for correcting the barycentric coordinates of tessellated patch vertices that allows triangles in the terrain model to be docked without geometric discontinuities. Based on the distributed methods and algorithms developed, a program complex for virtual Earth surface visualization was created and successfully tested. The proposed solution can also be employed in virtual environment systems, virtual labs, educational geo-applications, etc.
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