This paper describes a head-neck-eye camera system that is capable of learning to saccade to 3-D targets in a self-organized fashion. The self-organized learning process is based on action perception cycles where the ...
详细信息
This paper describes a head-neck-eye camera system that is capable of learning to saccade to 3-D targets in a self-organized fashion. The self-organized learning process is based on action perception cycles where the camera system performs micro saccades about a given head-neck-eye camera position and learns to map these Micro saccades to changes in position of a 3-D target currently in view of the stereo camera. This motor babbling phase provides self-generated movement commands that activate correlated visual, spatial and Motor information that are used to learn ail internal coordinate transformation between vision and motor systems. The learned transform is used by resulting head-neck-eye camera system to accurately saccade to 3-D targets using many different combinations of head, neck, and eye positions. The interesting aspect of the learned transform is that it is robust to a wide variety of disturbances including reduced degrees of freedom of movement for the head, neck, one eye, or any combination of two of the three, movement of lead and neck as a function of eye movements, changes in the stereo camera separation distance and changes in focal lengths of the cameras. These disturbances were not encountered during motor babbling phase. This feature points to general nature of the learned transform in its ability to control autonomous systems with redundant degrees of freedom in a very robust and fault-tolerant fashion. (C) 2008 Elsevier Ltd. All rights reserved.
The state of a concurrent object, intended as some abstraction over the values of the fields of the object, usually determines its coordination behavior. Therefore, state is always in the programmer's mind, even t...
详细信息
The state of a concurrent object, intended as some abstraction over the values of the fields of the object, usually determines its coordination behavior. Therefore, state is always in the programmer's mind, even though implicitly. We suggest a feature for J ava-like languages, which makes the state of a concurrent object explicit and supports the expression of the object's behavior depending on the state it is currently in. Namely, an object will be in one of the states declared in its class. The state determines the presence of fields and methods. State transition statements explicitly change the state of an object, and thus change the availability of fields and methods. When a thread calls a method which is declared in the object's class but absent from its current state, it waits, until the state of the object changes to a state which does contain that method. This directly expresses coordination. We claim that this feature makes it easier to understand and develop concurrent programs, and substantiate our claim through the discussion of some popular examples of concurrent programs written using this *** develop a type and effect system, which guarantees that, during execution of a method invoked on a concurrent object. No attempt will be made to access fields not available in the current state of and (2) No method invoked on a receiver (syntactically) different from may cause the invocation of a method on the latter guarantee helps to enforce the former and prevents a family of accidental violations of the intended coordination protocol.
DESIGNERS HAVE BEGUN TO APPLY DYNAMIC IMAGE-PROCESSING algorithms IN FPGAs TO CONVERT AND MAP DIGITAL-VIDEO SIGNALS ONTO DISPLAY PANELS. MULTIPLE VIDEO-PROCESSING TECHNIQUES AND BUILDING BLOCKS EXIST TO HANDLE, PROCES...
详细信息
DESIGNERS HAVE BEGUN TO APPLY DYNAMIC IMAGE-PROCESSING algorithms IN FPGAs TO CONVERT AND MAP DIGITAL-VIDEO SIGNALS ONTO DISPLAY PANELS. MULTIPLE VIDEO-PROCESSING TECHNIQUES AND BUILDING BLOCKS EXIST TO HANDLE, PROCESS, AND DISPLAY CLEAN, SMOOTH PICTURES ON FLAT-PANEL HDTVs. Today's rapid proliferation of large-screen HDTVs (high-definition televisions) requires the use of highly complex video-processing algorithms to achieve high resolution, which in turn necessitates faster data rates to address the many artifacts that viewers would not typically notice on smaller screens. To overcome these challenges, designers are now beginning to apply dynamic image-processing algorithms in FPGAs to convert and map digital-video signals onto display panels. Designers are using many approaches for handling, processing, and displaying clean, smooth images on flat-panel HDTVs.
Previous work on autonomous formation flying guidance and control identified three key challenges to overcome in order to obtain a fully autonomous guidance and control loop: an accurate but simple model of relative m...
详细信息
Previous work on autonomous formation flying guidance and control identified three key challenges to overcome in order to obtain a fully autonomous guidance and control loop: an accurate but simple model of relative motion about elliptical and perturbed orbits, an efficient way of performing conflicting requirements trade-off with power-limited on-board computers, and finally an optimal or near-optimal control algorithm easy to implement on a flight computer. This paper first summarizes recent developments on each of these subject that help to overcome these challenges, developments which are then used as building blocks for an autonomous formation flying guidance and control system. This system autonomously performs trade-offs between conflicting requirements. i.e. minimization of fuel cost, formation accuracy and equal repartition of the fuel expenditure within the formation. Simulation results show that a complete guidance and control loop can be established using mainly analytical results and with very few numerical optimization which facilitates on-board implementation. (c) 2008 Elsevier Ltd. All rights reserved.
Label-free relative quantitative proteornics is a powerful tool for the survey of protein level changes between two biological samples. We have developed and applied an algorithm using chromatographic alignment of mu ...
详细信息
Label-free relative quantitative proteornics is a powerful tool for the survey of protein level changes between two biological samples. We have developed and applied an algorithm using chromatographic alignment of mu LC-MS runs to improve the detection of differences between complex protein mixtures. We demonstrate the performance of our software by finding differences in E. coli protein abundance upon induction of the lac operon genes using isopropyl P-D-thiogalactopyranoside. The use of our alignment gave a 4-fold decrease in mean relative retention time error and a 6-fold increase in the number of statistically significant differences between samples. Using a conservative threshold, we have identified 5290 total mu LC-MS regions that have a different abundance between these samples. Of the detected difference regions, only 23% were mapped to MS/MS peptide identifications. We detected 74 proteins that had a greater relative abundance in the induced sample and 21 with a greater abundance in the uninduced sample. We have developed an effective tool for the label-free detection of differences between samples and demonstrate an increased sensitivity following chromatographic alignment.
We present a novel representation and algorithm, ReduceM, for memory efficient ray tracing of large scenes. ReduceM exploits the connectivity between triangles in a mesh and decomposes the model into triangle strips. ...
详细信息
We present a novel representation and algorithm, ReduceM, for memory efficient ray tracing of large scenes. ReduceM exploits the connectivity between triangles in a mesh and decomposes the model into triangle strips. We also describe a new stripification algorithm, Strip-RT, that can generate long strips with high spatial coherence. Our approach uses a two-level traversal algorithm for ray-primitive intersection. In practice, ReduceM can significantly reduce the storage overhead and ray trace massive models with hundreds of millions of triangles at interactive rates on desktop PCs with 4-8GB of main memory.
Adaptive decimation ( AD) is a technique that aims at compressing images with a very small amount of computations and memory requirement. For images that contain moderate amounts of textural content, the method exhibi...
详细信息
Adaptive decimation ( AD) is a technique that aims at compressing images with a very small amount of computations and memory requirement. For images that contain moderate amounts of textural content, the method exhibits satisfactory performance and in general provides good visual quality and acceptable coding fidelity at low bit-rate of around 0.2 bpp. Although the complexity of the method is relatively light when compared with the existing compression methods, it still involves a considerable amount of computations that would require the use of medium-speed processors to achieve real-time operation. In the paper, a novel image encoder based on the principles of AD is reported. The scheme is near-computation-free as it involves on average a single fixed point multiplication plus a few other summing and logical operations for every four pixels. Experimental results reveal that, despite the substantial reduction in complexity, the performance of proposed method is similar to, if not better than, the existing AD encoding algorithms.
An implementation of a computational tool to generate new summaries from new source texts is presented, by means of the connectionist approach (artificial neural networks). Among other contributions that this work int...
详细信息
An implementation of a computational tool to generate new summaries from new source texts is presented, by means of the connectionist approach (artificial neural networks). Among other contributions that this work intends to bring to natural language processing research, the use of a more biologically plausible connectionist architecture and training for automatic summarization is emphasized. The choice relies on the expectation that it may bring an increase in computational efficiency when compared to the sa-called biologically implausible algorithms.
In this paper, an unstructured Chimera mesh method is used to compute incompressible flow around a rotating body. To implement the pressure correction algorithm on unstructured overlapping sub-grids, a novel interpola...
详细信息
In this paper, an unstructured Chimera mesh method is used to compute incompressible flow around a rotating body. To implement the pressure correction algorithm on unstructured overlapping sub-grids, a novel interpolation scheme for pressure correction is proposed. This indirect interpolation scheme can ensure a tight coupling of pressure between sub-domains. A moving-mesh finite volume approach is used to treat the rotating sub-domain and the governing equations are formulated in an inertial reference frame. Since the mesh that surrounds the rotating body undergoes only solid body rotation and the background mesh remains stationary, no mesh deformation is encountered in the computation. As a benefit from the utilization of an inertial frame, tensorial transformation for velocity is not needed. Three numerical simulations are successfully performed. They include flow over a fixed circular cylinder, flow over a rotating circular cylinder and flow over a rotating elliptic cylinder. These numerical examples demonstrate the capability of the current scheme in handling moving boundaries. The numerical results are in good agreement with experimental and computational data in literature. (C) 2007 Elsevier Ltd. All rights reserved.
With the growing popularity of the MPEG-1 Audio Layer 3 (MP3) format, handheld devices such as personal digital assistants (PDAs) and mobile phones have become important entertainment platforms. Unlike conventional au...
详细信息
With the growing popularity of the MPEG-1 Audio Layer 3 (MP3) format, handheld devices such as personal digital assistants (PDAs) and mobile phones have become important entertainment platforms. Unlike conventional audio equipment, mobile devices are characterized by limited processing power, battery life, and memory, as well as other constraints. Therefore, music-processing tasks like beat detection must be implemented using low-complexity algorithms to cope with the constraints of these mobile devices.
暂无评论