37102468
Variable Block Size Motion Vector Retrieval Schemes for H.264 Inter Frame Error Concealment
With the ubiquitous application of Internet and wireless networks, H.264 video communication becomes more and more common. However, due to the high-efficiently predictive coding and the variable length entropy coding, it is more sensitive to transmission errors. The current error concealment (EC) scheme, which utilizes the spatial and temporal correlations to conceal the corrupted region, produces unsatisfied boundary artifacts. In this paper, first we propose variable block size error concealment (VBSEC) scheme inspired by variable block size motion estimation (VBSME) in H.264. This scheme provides four EC modes and four sub-block partitions. The whole corrupted macro-block (MB) will be divided into variable block size adaptively according to the actual motion. More precise motion vectors (MV) will be predicted for each sub-block. Then MV refinement (MVR) scheme is proposed to refine the MV of the heterogeneous sub-block by utilizing three step search (TSS) algorithm adaptively. Both VBSEC and MVR are based on our directional spatio-temporal boundary matching algorithm (DSTBMA). By utilizing these schemes, we can reconstruct the corrupted MB in the inter frame more accurately. The experimental results show that our proposed scheme can obtain better objective and subjective EC quality, respectively compared with the boundary matching algorithm (BMA) adopted in the JM11.0 reference software, spatio-temporal boundary matching algorithm (STBMA) and other comparable EC methods.
28547446
Low-Complex Equalization for Single Carrier Systems Employing Cyclic Prefix over Time-Variant Channels
A simplified equalization method based on the band structure of the frequency domain channel matrix is proposed for the single carrier systems employing cyclic prefix (SC-CP) over time-varying wireless channels. Using both theoretical analysis and computer simulation, it is shown that the complexity of this method is proportional to the number of symbols in one SC-CP block and is less than that of traditional block equalization methods. We also show that they have similar performance.
45070598
An Adaptive Spatial Error Concealment for H.264/AVC Video Stream
A drill guide for positioning on a surface of a bone includes a projection for penetrating the bone, an abutment for engaging the surface of the bone to ensure penetration of the bone by the projection to a predetermined depth, less than the length of the projection, and a pair of guide passages having central longitudinal axes, respectively, converging at a predetermined point in the bone when the projection penetrates the bone to the predetermined depth. A kit for fixating soft tissue to bone includes a drill guide, a drill bit, a suture and a suture passer. The drill bit is insertable in a pair of guide passages of the drill guide to cut first and second passages converging in the bone to define a continuous tunnel. The suture passer has a portion for being introduced in the tunnel to engage the suture externally of the bone such that the suture is drawn through the tunnel when the suture passer is withdrawn therefrom. A method of fixating soft tissue to bone includes the steps of penetrating a bone with a projection of a drill guide, engaging the bone with an abutment of the drill guide to ensure penetration of the bone by the projection to a predetermined depth, introducing a drill bit through a pair of guide passages of the drill guide and into the bone to form first and second passages converging in the bone to define a continuous tunnel, introducing a suture passer into the tunnel such that a suture engaging member of the suture passer protrudes externally of the bone, engaging a suture with the suture engaging member, withdrawing the suture passer from the tunnel to draw the suture through the tunnel and using the suture to fixate soft tissue to the bone.
7144886
Khatri-Rao Unitary Space-Time Modulation
Based on the Khatri-Rao matrix product, we propose a novel unitary space-time modulation design called KR-USTM in this paper. Different from existing USTM schemes, such as the systematic approach and space-time frequency-shift keying (ST-FSK), KR-USTM does not require any computer search and can be applied to any number of transmit antennas. Moreover, the special structure of KR-USTM also makes it a high-rate scheme and achieve full antenna diversity as well as lower decoding complexity. Simulation results show that the proposed KR-USTM constellation achieves error performance comparable to existing USTM designs at low rates, while it outperforms them at high rates.
16763535
Handling Significant Scale Difference for Object Retrieval in a Supermarket
We propose an object retrieval application which can retrieve user specified objects from a big supermarket. Significant and unpredictable scale difference between the query and the database image is the major obstacle encountered. The widely used local invariant features show their deficiency in such an occasion. To improve the situation, we first design a new weighting scheme which can assess the repeatability of local features against scale variance. Also, another method which deals with scale difference through retrieving a query under multiple scales is also developed. Our methods have been tested on a real image database collected from a local supermarket and outperform the existing local invariant feature based image retrieval approaches. A new spatial check method is also briefly discussed.
1252619
A fast approximate algorithm for training L1-SVMs in primal space
We propose a novel and fast algorithm to train support vector machines (SVMs) in primal space, which solves an approximate optimization of SVMs with the properties of unconstraint, continuity and twice differentiability by utilizing the Newton optimization technique. Further, we devise a special pre-extracting procedure to speed up the convergence of the algorithm by resorting to a high-quality initial solution. Theoretical studies show that the proposed algorithm produces an @?-approximate solution to standard SVMs and maintains low computational complexity. Experimental results on benchmark data sets demonstrate that our algorithm is much faster than the dual based method such as SVM^l^i^g^h^t while it achieves the similar test accuracy.
11258056
Data I/O Minimization for Loops on Limited Onchip Memory Processors
Due to significant advances in VLSI technology, ‘mega-processors’ made with a large number of transistors has become a reality. These processors typically provide multiple functional units which allow exploitation of parallelism. In order to cater to the data demands associated with parallelism, the processors provide a limited amount of on-chip memory. The amount of memory provided is quite limited due to higher area and power requirements associated with it. Even though limited, such on-chip memory is a very valuable resource in memory hierarchy. An important use of on-chip memory is to hold the instructions from short loops along with the associated data for very fast computation. Such schemes are very attractive on embedded processors where, due to the presence of dedicated hard-ware on-chip (such as very fast multipliers-shifters etc.) and extremely fast accesses to on-chip data, the computation time of such loops is extremely small meeting almost all real-time demands. Biggest bottleneck to performance in these cases are off-chip accesses and thus, compilers must carefully analyze references to identify good candidates for promotion to on-chip memory. In our earlier work [6], we formulated this problem in terms of 0/1 knapsack and proposed a heuristic solution that gives us good promotion candidates. Our analysis was limited to a single loop nest. When we attempted extending this framework to multiple loop nests (intra-procedurally), we realized that not only it is important to identify good candidates for promotion but a careful restructuring of loops must be undertaken before performing promotion since data i/o of loading and storing values to on-chip memory poses a significant bottleneck.
45698420
An Approximate Solution for Queuing Network Models of a Burst-Level Traffic Control Scheme in ATM WAN
Abstract This paper proposes a closed queuing network model for a burst-level traffic control scheme in ATM WAN environments, and explores solution techniques for this model. An approximate solution technique is developed to solve the closed queuing networks with multiple chains, chain-dependent service times, MSFIFO (multiple servers first-in first-out) queues, and simultaneous resource possession. Results of this study show that, with respect to the subnetwork algorithm of Souza e Silva and Muntz [Approximate solution for a class of non-product form queuing network models, Performance Evaluation (7) (1987) 221–242], our algorithm is advantageous, because (1) it is applicable to queuing network models with nested first-allocated/first-released passive resources; (2) it greatly reduces the complexity of the subnetwork algorithm by not decomposing the network and representing the complements; (3) it achieves higher accuracy and provides more reliable conservative estimates; and (4) it is easy to understand due to its straightforward interpretation.
16543010
A novel multi-resolution video representation scheme based on kernel PCA
Content-based video analysis calls for efficient and flexible video representation. In this paper, a novel multi-resolution video representation (MRVR) scheme is proposed and realized by performing the kernel principal component analysis (KPCA) on the low-level visual features extracted from a video sequence. By simply changing the kernel parameters or the dimensionality of the subspace, this scheme can represent video content from coarser to finer levels in the subspace, according to its intrinsic structure. An application of keyframe extraction is investigated to show the advantages of this representation scheme. Furthermore, based on this scheme, a two-level video summarization approach is proposed to represent long video sequences. The experimental results of both short and long video sequences have demonstrated the effectiveness and flexibility of the proposed video representation scheme.