A RFID group scanning protocol enables a RFID reader to produce a proof of co-existence of multiple RFID tags. This type of protocol is also referred to as yoking-proof, grouping-proof and co-existence proof. In this letter, we show that all of the previous group scanning protocols are vulnerable to relay attack.

The key problem of object-based attention is the definition of objects, while contour grouping methods aim at detecting the complete boundaries of objects in images. In this paper, we develop a new contour grouping method which shows several characteristics. First, it is guided by the global saliency information. By detecting multiple boundaries in a hierarchical way, we actually construct an object-based attention model. Second, it is optimized by the grouping cost, which is decided both by Gestalt cues of directed tangents and by region saliency. Third, it gives a new definition of Gestalt cues for tangents which includes image information as well as tangent information. In this way, we can improve the robustness of our model against noise. Experiment results are shown in this paper, with a comparison against other grouping model and space-based attention model.

Boundary detection is one of the most studied problems in computer vision. It is the foundation of contour grouping, and initially affects the performance of grouping algorithms. In this paper we propose a novel boundary detection algorithm for contour grouping, which is a selective attention guided coarse-to-fine scale pyramid model. Our algorithm evaluates each edge instead of each pixel location, which is different from others and suitable for contour grouping. Selective attention focuses on the whole saliency objects instead of local details, and gives global spatial prior for boundary existence of objects. The evolving process of edges through the coarsest scale to the finest scale reflects the importance and energy of edges. The combination of these two cues produces the most saliency boundaries. We show applications for boundary detection on natural images. We also test our approach on the Berkeley dataset and use it for contour grouping. The results obtained are pretty good.

A sound field reproduction method is proposed that uses blind source separation and a head-related transfer function. In the proposed system, multichannel acoustic signals captured at distant microphones are decomposed to a set of location/signal pairs of virtual sound sources based on frequency-domain independent component analysis. After estimating the locations and the signals of the virtual sources by convolving the controlled acoustic transfer functions with each signal, the spatial sound is constructed at the selected point. In experiments, a sound field made by six sound sources is captured using 48 distant microphones and decomposed into sets of virtual sound sources. Since subjective evaluation shows no significant difference between natural and reconstructed sound when six virtual sources and are used, the effectiveness of the decomposing algorithm as well as the virtual source representation are confirmed.

In memory design, the issue is smaller size and low power. Most power used in the ROM is consumed in line capacitance such as address lines, word lines, bit lines, and decoder. This paper presents ROM design of a novel HG (Half Grouping) compression method so as to reduce the parasitic capacitance of bit lines and the area of the row decoder for power consumption and chip area reduction. ROM design result of 512 point FFT block shows that the proposed method reduces 40.6% area, 42.12% power, and 37.82% transistor number respectively in comparison with the conventional method. The designed ROM with proposed method is implemented in a 0.35 µm CMOS process. It consumes 5.8 mW at 100 MHz with a single 3.3 V power supply.

We propose an antenna grouping method that improves the error rate performance of space-time codes in a wide range of mobility environments. The idea is to group symbols to antennas based on limited feedback from the mobile station to utilize all antennas. Our approach requires only two bits of feedback information to achieve better link performance and full rate for a certain four transmit antenna system. Numerical results confirm the bit/frame error gains over the Alamouti-based space-time block code and antenna subset selection strategies.

Crosstalk delay within an on-chip bus can induce severe transmission performance penalties. The Bus-grouping Asynchronous Transmission (BAT) scheme is proposed to mitigate the performance degradation. Furthermore, considering the distinct spatial locality of transition distribution on some types of buses, we use the locality to optimize the BAT. In terms of the implementation, we propose the Differential Counter Cluster (DCC) synchronous mechanism to synchronize the data transmission, and the Delay Active Shielding (DAS) to protect some critical signals from crosstalk and optimize the routing area overhead. The BAT is scalable with the variation of bus width with little extra implementation complexity. The effectiveness of the BAT is evaluated by focusing on the on-chip buses of a superscalar microprocessor simulator using the SPEC CPU2000 benchmarks. When applied to a 64-bit on-chip instruction bus, the BAT scheme, compared with the conservative approach, Codec and Variable Cycle Transmission (DYN) approaches, improves performance by 55+%, 10+%, 30+%, respectively, at the expense of 13% routing area overhead.

In this paper, we propose a method for enhancing performance of a sequential version of the belief-propagation (BP) decoding algorithm, the group shuffled BP decoding algorithm for low-density parity-check (LDPC) codes. An improved BP decoding algorithm, called the shuffled BP decoding algorithm, decodes each symbol node in serial at each iteration. To reduce the decoding delay of the shuffled BP decoding algorithm, the group shuffled BP decoding algorithm divides all symbol nodes into several groups. In contrast to the original group shuffled BP, which automatically generates groups according to symbol positions, in this paper we propose a method for grouping symbol nodes which generates groups according to the structure of a Tanner graph of the codes. The proposed method can accelerate the convergence of the group shuffled BP algorithm and obtain a lower error rate in a small number of iterations. We show by simulation results that the decoding performance of the proposed method is improved compared with those of the shuffled BP decoding algorithm and the group shuffled BP decoding algorithm.

In MC-CDMA systems, subcarriers can be shared by different users. In this letter, we exploit the shared nature of subcarriers and propose a user grouping and subcarrier allocation algorithm for grouped MC-CDMA systems. The scheme aims at maximizing the total system throughput while providing bandwidth-fairness among groups. Simulation results are given to demonstrate the performance of the proposed algorithm in terms of sum capacity and per-user throughput.

Some major P2P file distribution systems adopt Tit-For-Tat exchange strategy, which means "initially cooperate, then respond in kind to a previous opponent's action, i.e. cooperative or not." However, when sharing a file on such P2P systems, the random peer selection has a problem in that each peer cannot download the file enough efficiently. The peer selection method that groups peers according to their rate has been proposed to solve this problem. This method is supposed to be able to alleviate the difference in performance among peers because it lets peers with similar transmitting rate connect to each other. However, when reduction in peer performance or link one occurs, which is often observed on today's Internet, some problems will emerge, such as it takes a long time for the existing method to reconfigure groups; 2) immediate reconstruction of neighbor peers has not been taken into account when peers detect deterioration in downloading performance. Therefore, we propose a method that reconfigures the group of neighbor peers once a peer notices that the performance of connected peers decreases. The proposed method is evaluated through simulation experiments using BitTorrent as an instance of Tit-For-Tat strategy. The download time of all peers and that of the peer with performance deterioration are estimated focusing on the effect of switching a degraded peer to another immediately. As a result, we confirm that our proposal can distribute files among all peers faster than the existing method keeping incentives for users to some extent. We believe that the proposal which can adapt to the sudden network deterioration is one of the most important technologies for evolution of network software.

3G must offer high data rates since it should support real-time multimedia services; one performance enhancement, the use of the OVSF code tree, has adopted in 3G WCDMA networks. Unfortunately, this technique allows the link capacity to be set at the base rate times powers of two. This results in wasting bandwidth while the required rate is not powers of two of the basic rate. Several multi-code assignment mechanisms have been proposed to reduce the waste rate, but incur some drawbacks, including high complexity of handling multiple codes and increasing cost of using more rake combiners. Our solution is a dynamic grouping code assignment that allows any rate to be achieved with a single code for any possible rate of traffic. The dynamic grouping approach first forms several calls into a group. It then allocates a subtree to the group and dynamically shares the subtree codes based on time-sharing of slots within a group cycle time. The waste rate and code blocking is thus reduced significantly. Since transmission delay and jitter may occur in such a time-sharing approach, two schemes of cycle interleaving are proposed to minimize delay and jitter. Numerical results demonstrate that the proposed approach reduces the waste rate and increases the system utilization obviously, and the proposed cycle interleaving schemes minimizes delay and jitter significantly.

According to the Gestalt principals, this paper presents a recognition method of grouping areas in trademark images modeling features for measuring the attraction degree between couples of image components. This investigation would be used for content-based image retrieval from the view of mirroring human perception for images. Depending on variability in human perception for trademark images, the proposed method finds grouping areas by calculating Mahalanobis distance with the features to every combination of two components in images. The features are extracted from every combination of two components in images, and the features represent proximity, shape similarity, and closure between two components. In addition, changing combination of the features, plural grouping patterns are output. Besides, this paper shows the efficiency and limits of the proposed method from experimental results. In the experiments, 104 participants have perceived grouping patterns to 74 trademark images and the human perceptions have been compared with outputs by the proposed method for the 74 images.

To guarantee the high reliability of video services, video servers usually adopt parity-encoding techniques in which data blocks and their associated parity blocks form a parity group. For real-time video service, all the blocks in a parity group are prefetched in order to cope with a possible disk failure, thereby incurring a buffering overhead. In this paper, we propose a new scheme called Round-level Parity Grouping (RPG) to reduce the buffer overhead while restoring VBR video streams in the presence of a faulty disk. RPG allows variable parity group sizes so that the exact amount of data is retrieved during each round. Based on RPG, we have developed a storage allocation algorithm for effective buffer management. Experimental results show that our proposed scheme reduces the buffer requirement by 20% to 25%.

For large circuits, vector compaction techniques could provide a faster solution for power estimation with reasonable accuracy. Because traditional sampling approach will incur useless transitions between every sampled pattern pairs after they are concatenated into a single sequence for simulation, we proposed a vector compaction method with grouping and single-sequence consecutive sampling technique to solve this problem. However, it is very possible that we cannot find a perfect consecutive sequence without any undesired transitions. In such cases, the compaction ratio of the sequence length may not be improved too much. In this paper, we propose an efficient approach to relax the limitation a little bit such that multiple consecutive sequences are allowed. We also propose an algorithm to reduce the number of sequences instead of setting the number as one to find better solutions for vector compaction problem. As demonstrated in the experimental results, the average compaction ratio and speedup can be significantly improved by using this new approach.

In this paper, we presented a new interference suppression method based on groupwise decorrelation for the multirate wideband-code division multiple access (W-CDMA) downlink. Code grouping in the proposed method is performed according to the correlation property between the mother code and the child code in the orthogonal variable spreading factor (OVSF) code tree. The decorrelation process based on the grouped codes, so called groupwise decorrelation, is then performed to suppress the interference induced in the downlink propagation. We demonstrate that the proposed method can enhance the performance significantly, with lower computational complexity and higher operational efficiency in which any information about interference users (code, data, amplitude) is not required to know in prior at the detection stage.

This paper proposes a test generation method using several partly compacted test plan tables for RTL data paths. Combinational modules in data paths are tested using several partly compacted test plan tables. Each partly compacted test plan table is generated from each grouped test plan set and is used to test combinational modules corresponding to the grouped test plans. The values of control signals in a partly compacted test plan table are supplied by a test controller. This paper also proposes the architecture of a test controller which can be synthesized in a reasonable amount of time, and proposes a test plan grouping method to shorten test length for data paths under a test controller area constraint. Experimental results for benchmarks show that the test lengths are shortened by 4 to 36% with -9 to 8% additional test controller area compared with the test generation method using test plans.

In this paper, we propose an efficient IP-Level power model with a small lookup table for complex CMOS circuits. The table has only one dimension that maps the zero-delay charging and discharging capacitance (CDC) into the real power consumption of pattern pairs but still has high accuracy. In order to reduce the table size, we collect those pattern pairs with similar CDC values to be a group and only set an entry in the lookup table for each group. The proposed dynamic grouping process can automatically increase the entries of the lookup tables to cover the current CDC distribution of designs during the power characterization process. In order to improve the efficiency of characterization process, the Monte Carlo approach is used during the estimation for the average power of each group to skip the samples that will not increase the accuracy too much. After the power model of a circuit is built, the average power consumption for any test sequence can be estimated easily. The experimental result shows that the table sizes are only up to 107 entries for ISCAS'85 benchmark circuits and the estimation error is only 2.99% on average using this lookup table.

A new algorithm for synthesizing binary threshold neural networks (BTNNs) is proposed. A binary (Boolean) input-output mapping that can be represented by minimal sum-of-product (MSP) terms is initially obtained from training data. The BTNN is then synthesized based on an MSP term grouping method. As a result, a fast and optimal realization of a BTNN can be obtained. Examples of both feedforward and recurrent BTNN synthesis used in a parallel processing architecture are given and compared with other existing methods.

Grouping multiple voice frames into a single IP packet ("frame grouping") is a commonly mentioned approach to saving bandwidth in IP telephony. But little is known as to when, how, and how much frame grouping should be done in Internet environment. This paper explores the feasibility and the methods of frame grouping based on Internet delay measurement. Specifically, we propose an adaptive frame grouping method that minimizes the delay violation while reducing the bandwidth usage by as much as a factor of two under real Internet delay fluctuations. The performance of the method is evaluated as it is used against a single voice stream and then against multiple voice streams.

A framework is proposed for segmenting image textures by using Gabor filters to detect boundaries between adjacent textured regions. By performing a multi-channel filtering of the input image with a small set of adaptively selected Gabor filters, tuned to underlying textures, feature images are obtained. To reduce the variance of the filter output for better texture boundary detection, a Gaussian post-filter is applied to the Gabor filter response over each channel. Significant local variations in each channel response are detected using a gradient operator, and combined through channel grouping to produce the texture gradient. A subsequent post-processing produces expected texture boundaries. The effectiveness of the proposed technique is demonstrated through experiments on synthetic and natural textures.