Reducing the power dissipation for LDPC code decoder is a major challenging task to apply it to the practical digital communication systems. In this paper, we propose a low power LDPC code decoder architecture based on an intermediate message-compression technique which features as follows: (i) An intermediate message compression technique enables the decoder to reduce the required memory capacity and write power dissipation. (ii) A clock gated shift register based intermediate message memory architecture enables the decoder to decompress the compressed messages in a single clock cycle while reducing the read power dissipation. The combination of the above two techniques enables the decoder to reduce the power dissipation while keeping the decoding throughput. The simulation results show that the proposed architecture improves the power efficiency up to 52% and 18% compared to that of the decoder based on the overlapped schedule and the rapid convergence schedule without the proposed techniques respectively.

As power consumption of the clock tree dominates over 40% of the total power in modern high performance VLSI designs, measures must be taken to keep it under control. One of the most effective methods is based on clock gating to shut off the clock when the modules are idle. However, previous works on gated clock tree power minimization are mostly focused on clock routing and the improvements are often limited by the given registers placement. The purpose of this work is to navigate the registers during placement to further reduce the clock tree power based on clock gating. Our method performs activity-aware register clustering that reduces the clock tree power not only by clumping the registers into a smaller area, but also by pulling the registers with the similar activity patterns closely to shut off the clock more time for the resultant subtrees. In order to reduce the impact of signal nets wirelength and power due to register clustering, we apply the timing and activity based net weighting in [14], which reduces the nets switching power by assigning a combination of activity and timing weights to the nets with higher switching rates or more critical timing. To tradeoff the power dissipated by the clock tree and the control signal, we extend the idea of local ungating in [6] and propose an algorithm of gate control signal optimization, which still sets the gate enable signal high if a register is active for a number of consecutive clock cycles. Experimental results on a set of MCNC benchmarks show that our approach is able to reduce the power and total wirelength of clock tree greatly with minimal overheads.

In mass disasters such as earthquakes, fire disasters, tsunami, and terrorism, dental records have been used for identifying victims due to their processing time and accuracy. The greater the number of victims, the more time the identification tasks require, since a manual comparison between the dental radiograph records is done by forensic experts. Addressing this problem, this paper presents an efficient dental radiograph recognition system using Phase-Only Correlation (POC) for human identification. The use of phase components in 2D (two-dimensional) discrete Fourier transforms of dental radiograph images makes possible to achieve highly robust image registration and recognition. Experimental evaluation using a set of dental radiographs indicates that the proposed system exhibits efficient recognition performance for low-quality images.

In this letter, a semi-automatic method for road network extraction from high-resolution satellite images is proposed. First, we focus on detecting the seed points in candidate road regions using a method of self-organizing map (SOM). Then, an approach to road tracking is presented, searching for connected points in the direction and candidate domain of a road. A study of Geographical Information Systems (GIS) using high-resolution satellite images is presented in this letter. Experimental results verified the effectiveness and efficiency of this approach.

Image Registration can be seen as an optimization problem to find a cost function and then use an optimization method to get its minimum. Normalized mutual information is a widely-used robust method to design a cost function in medical image registration. Its calculation is based on the joint histogram of the fixed and transformed moving images. Usually, only a discrete joint histogram is considered in the calculation of normalized mutual information. The discrete joint histogram does not allow the cost function to be explicitly differentiated, so it can only use non-gradient based optimization methods, such as Powell's method, to seek the minimum. In this paper, a parzen-window based method is proposed to estimate the continuous joint histogram in order to make it possible to derive the close form solution for the derivative of the cost function. With this help, we successfully apply the gradient-based optimization method in registration. We also design a new kernel for the parzen-window based method. Our designed kernel is a second order polynomial kernel with the width of two. Because of good theoretical characteristics, this kernel works better than other kernels, such as a cubic B-spline kernel and a first order B-spline kernel, which are widely used in the parzen-window based estimation. Both rigid and non-rigid registration experiments are done to show improved behavior of our designed kernel. Additionally, the proposed method is successfully applied to a clinical CT-MR non-rigid registration which is able to assist a magnetic resonance (MR) guided microwave thermocoagulation of liver tumors.

This paper describes a modified ICP registration system of facial point data with range-scanning equipment for medical Augmented Reality applications. The reference facial point data are extracted from the pre-stored CT images; the floating facial point data are captured from range-scanning equipment. A modified soft-shape-context ICP including an adaptive dual AK-D tree for searching the closest point and a modified shape-context objective function is used to register the floating data to reference data to provide the geometric relationship for a medical assistant system and pre-operative training. The adaptive dual AK-D tree searches the closest-point pair and discards insignificant control coupling points by an adaptive distance threshold on the distance between the two returned closest neighbor points which are searched by using AK-D tree search algorithm in two different partition orders. In the objective function of ICP, we utilize the modified soft-shape-context information which is one kind of projection information to enhance the robustness of the objective function. Experiment results of using touch and non-touch capture equipment to capture floating point data are performed to show the superiority of the proposed system.

We propose feedback-limited NFSRs (nonlinear feedback shift registers) which can generate periodic sequences of period 2k-1, where k is the length of the register. We investigate some characteristics of such periodic sequences. It is also shown that the scale of such NFSRs can be reduced by the feedback limitation. Some simulation and experimental results are shown including comparison with LFSRs (linear feedback shift registers) for conventional M-sequences and Gold sequences.

We developed a comprehensive simulation system for evaluating satellite-based navigation services in highly built-up areas; the system can accommodate Global Positioning System (GPS) multipath effects, as well as line-of-sight (LOS) and dilution of position (DOP) issues. For a more realistic simulation covering multipath and diffracted signal propagations, a 3D-ray tracing method was combined with a satellite orbit model and three-dimensional (3D) geographic information system (GIS) model. An accuracy estimation model based on a 3D position determination algorithm with a theoretical delay-locked loop (DLL) correlation computation could measure the extent to which multipath mitigation improved positioning accuracy in highly built-up areas. This system could even capture the multipath effect from an invisible satellite, one of the greatest factors in accuracy deterioration in highly built-up areas. Further, the simulation results of satellite visibility, DOP, and multipath occurrence were mapped to show the spatial distribution of GPS availability. By using object-oriented programming, our simulation system can be extended to other global navigation satellite systems (GNSSs) simply by adding the orbital information of the corresponding GNSS satellites. We demonstrated the applicability of our simulation system in an experimental simulation for Shinjuku, an area of Tokyo filled with skyscrapers.

Under the assumption that clock can be inputted to each register at an arbitrary timing, the minimum feasible clock period can be determined if delays between registers are given. This minimum feasible clock period might be reduced by register relocation maintaining the circuit behavior and topology. In this paper, we propose a gate-level register relocation method to reduce the minimum feasible clock period. The proposed method is a greedy local circuit modification method. We prove that the proposed method achieves the clock period achieved by retiming with delay decomposition, if the delay of each element in the circuit is unique. Experiments show that the computation time of the proposed method and the number of registers of a circuit obtained by the proposed method are smaller than those obtained by the retiming method in the conventional synchronous framework.

High power consumption and slow access of enlarged and multiported register files make it difficult to design high performance superscalar processors. The clustered architecture, where the conventional monolithic register file is partitioned into several smaller register files, is expect to overcome the register file issues. In the clustered architecture, the more a monolithic register file is partitioned, the lower power and faster access register files can be realized. However, the partitioning causes losses of IPC (instructions per clock cycle) due to communication among register files. Therefore, degree of partitioning has a strong impact on the trade-off between power consumption and performance. In addition, the organization of partitioned register files also affects the trade-off. In this paper, we attempt to investigate appropriate degrees of partitioning and organizations of partitioned register files in a clustered architecture to assess the trade-off. From the results of execute-driven simulation, we find that the organization of register files and the degree of partitioning have a strong impact on the IPC, and the configuration with non-consistent register files can make use of the partitioned resources more effectively. From the results of register file access time and energy modeling, we find that the configurations with the highly partitioned non-consistent register file organization can receive benefit of the partitioning in terms of operating frequency and access energy of register files. Further, we examine relationship between IPS (instructions per second) and the product of IPC and operating frequency of register files. The results suggest that highly partitioned non-consistent configurations tends to gain more advantage in performance and power.

Paging extensions for Mobile Internet Protocol (P-MIP) decreases only the number of registration, but it does not much improve the method of registration, which still gives rise to a lot of lost packets and long handoff latency, and may also waste the data buffering and time during registration. In the active state, P-MIP behaves in the same way as Mobile Internet Protocol (MIP), thus, in this state, the packet loss rate of P-MIP is the same as that of MIP. However, the packet loss rate of P-MIP is lower than that of MIP, when changing from idle state to active state, because P-MIP buffers packets at the registered FA. We propose an improvement method for the registration delay, while the mobile node is entering the active state to decrease the mobile node waiting time for data packets. The proposed method can reduce the requirement of data buffering and also improve the method of registration to decrease lost packets and handoff latency when the mobile node moves across the cell in the same paging area during active state.

Modern processors have large instruction windows to improve performance. They usually adopt register renaming, where every active instruction with a valid destination needs a physical register. As the instruction windows get larger, however, bigger physical register files are required. To solve this problem, we proposed a physical register sharing technique. It shares a physical register among multiple instructions based on a value similarity. As a result, we achieved performance improvement without increasing the size of the physical register file. In addition, the proposed technique can also be used to reduce the timing, complexity and area overhead of the physical register file.

A new method for automatically building statistical shape models from a set of training examples and in particular from a class of hands. In this study, we utilise a novel approach to automatically recover the shape of hand outlines from a series of 2D training images. Automated landmark extraction is accomplished through the use of the self-organising model the growing neural gas (GNG) network, which is able to learn and preserve the topological relations of a given set of input patterns without requiring a priori knowledge of the structure of the input space. The GNG is compared to other self-organising networks such as Kohonen and Neural Gas (NG) maps and results are given for the training set of hand outlines, showing that the proposed method preserves accurate models.

The latest processors employ a large instruction window and longer pipelines to achieve higher performance. Although current branch predictors show high accuracy, the misprediction penalty is getting larger in proportion to the number of pipeline stages and pipeline width. This negative effect also happens in case of exceptions or interrupts. Therefore, it is important to recover processor state quickly and restart processing immediately. In this letter, we propose a low-cost recovery mechanism for processors with large instruction windows.

We introduce a new hierarchical key management scheme which can be applied for secure Mobile IP registration protocol. Contrary to the previous schemes, AAA protocol used for registration key distribution is separated from the base registration protocol, so that the registration key distribution can be simplified and the delay caused by the AAA protocol can be avoided. Also proposed is the non-repudiation service based on a hash chain, which is useful for secure auditing.

In this paper, a new implementation of the Viterbi decoder is proposed. The Modified State-Mapping VD algorithm combines the TB algorithm with the RE algorithm. By updating the starting point of the state for each memory bank, and by using Trace Back and Trace Forward information, LIFO (Last Input First Output) operation can be eliminated, which reduces the latency of the TB algorithm and decreases the resource usage of the RE algorithm. When the memory unit is 3, the resource usage is 13184 bits and the latency is 54 clocks. The latency of the proposed algorithm is 25% smaller than the MRE algorithm and 50% smaller than the k-pointer even TB algorithm. In addition, resource usage is 50% smaller than the RE algorithm. The resource usage is a little larger than that of the MRE algorithm for the small value of k, but it becomes smaller after k is larger than 16.

A comparison of performances is made of three text-independent speaker identification methods based on dual Penalized Logistic Regression Machine (dPLRM), Support Vector Machine (SVM) and Gaussian Mixture Model (GMM) with experiments by 10 male speakers. The methods are compared for the speech data which were collected over the period of 13 months in 6 utterance-sessions of which the earlier 3 sessions were for obtaining training data of 12 seconds' utterances. Comparisons are made with the Mel-frequency cepstrum (MFC) data versus the log-power spectrum data and also with training data in a single session versus in plural ones. It is shown that dPLRM with the log-power spectrum data is competitive with SVM and GMM methods with MFC data, when trained for the combined data collected in the earlier three sessions. dPLRM outperforms GMM method especially as the amount of training data becomes smaller. Some of these findings have been already reported in [1]-[3].

We have developed a 32-bit, 32-word, and 9-read, 7-write ported register file. This register file has several circuits and techniques for reducing the impact of process variation that is marked in recent process technologies, voltage variation, and temperature variation, so called PVT variation. We describe these circuits and techniques in detail, and confirm their effects by simulation and measurement of the test chip.

The present paper introduces an improved construction of a class of binary sequences having a zero-correlation zone (hereafter binary ZCZ sequence set). The cross-correlation function and the side-lobe of the auto-correlation function of the proposed sequence set is zero for the phase shifts within the zero-correlation zone. The present paper shows that such a construction generates a binary ZCZ sequence set from an arbitrary M-sequence. The previously reported sequence construction of binary ZCZ sequence sets from an M-sequence can generate a single series of binary ZCZ sequence sets from an M-sequence. The present paper proposes an improved sequence construction that can generate more than one series of binary ZCZ sequence sets from an M-sequence.

A novel distributed dynamic regional location management scheme called MORR (Mobility Oriented Regional Registration) is proposed for Mobile IP to improve the signaling traffic cost of a mobile node. This improvement is achieved by adjusting each mobile node's optimal regional domains according to its mobility behavior. With Mobile IP, the capricious mobility and variable traffic load of a mobile node has an impact on its average signaling traffic cost. In this paper, the mobility of all mobile nodes is classified into two modes: random mobility mode and regular mobility mode. We develop new analytical models to formulate the movement behavior and mathematically evaluate their characteristics when applied to these two modes. MORR has the adaptability to manipulate various mobility modes of each mobile node in dedicated ways to determine an optimal regional domain of this mobile node. Simulation results show that anywhere from 3 to 15 percent of the signaling cost is saved by MORR in comparison with the previous distributed dynamic location management schemes for various scenarios.