When LSIs that are designed and manufactured for low power dissipation are tested, test vectors that make the power dissipation low should be applied. If test vectors that cause high power dissipation are applied, incorrect test results are obtained or circuits under test are permanently damaged. In this paper, we propose a method to generate test sequences with low power dissipation for sequential circuits. We assume test sequences generated by an ATPG tool are given, and modify them while keeping the original stuck-at fault coverages. The test sequence is modified by inverting the values of primary inputs of every test vector one by one. In order to keep the original fault coverage, fault simulation is conducted whenever one value of primary inputs is inverted. We introduce heuristics that perform fault simulation for a subset of faults during the modification of test vectors. This helps reduce the power dissipation of the modified test sequence. If the fault coverage by the modified test sequence is lower than that by the original test sequence, we generate a new short test sequence and add it to the modified test sequence.

We suggest to use short secret keys in the anonymous group identification scheme proposed by Lee, Deng, and Zhu and prove that this scheme is secure under the discrete logarithm with short exponents assumption that solving the discrete logarithm problem modulo an n-bit prime p is hard even when the exponent is a small c-bit number. We show that the communication and the computation costs are lower than those of the Lee-Deng-Zhu scheme.

A novel modified midtread quantizer is proposed for number-controlled oscillator frequency quantization in digital phase-locked loops (DPLLs). We show that DPLLs employing the proposed quantizer provide significantly improved cycle slip performance compared to those employing conventional midtread or midrise quantizers, especially when the number of quantization bits is small and the magnitude of input signal frequency normalized by the quantization interval is less than 0.5.

Viterbi search engine in speech recognition consumes many computation time and hardware resource for finding maximum likelihood in HMM (Hidden Markov Model). We propose a fast Viterbi search engine using IHMM (Inverse Hidden Markov Model). A benefit of this method is that we can remove redundant computation of path matrix. The power consumption and the computational time are reduced by 68.6% at the 72.9% increase in terms of the number of gates.

Fast algorithms for computing the running type-I discrete sine transform (DST-I) and type-III discrete sine transform (DST-III) are proposed. The algorithms are based on a recursive relationship between three subsequent local discrete sine spectra. The computational complexity of the algorithms is compared with that of fast DST-I and DST-III algorithms. Fast inverse algorithms for signal processing in the running discrete sine transform domains are also proposed.

In this paper a new adaptive multi-input multi-output (MIMO) channel estimation and multiuser detection algorithm based kernel space iterative inversion is proposed. The functions of output signals are mapped from a low dimensional space to a high dimensional reproducing kernel Hilbert space. The function of the output signals is represented as a linear combination of a set of basis functions, and a Mercer kernel function is constructed by the distribution function. In order to avoid finding the function f(.) and g(.), the correlation among the output signals is calculated in the low dimension space by the kernel. Moreover, considering the practical application, the algorithm is extended to online iteration of mixture system. The computer simulation results illustrated that the new algorithm increase the performance of channel estimation, the global convergence, and the system stability.

A real-time frame-layer rate control algorithm using sliding window method is proposed for low bit rate video coding over the Internet. The proposed rate control method performs bit allocation at the frame level to minimize the average distortion over an entire sequence as well as variations in distortion between frames. A new frame-layer rate-distortion model is derived, and a non-iterative optimization method is used for low computational complexity. In order to reduce the quality fluctuation, we use a sliding window scheme which does not require the pre-analysis process. Therefore, the proposed algorithm does not produce time delay from encoding, and is suitable for real-time low-complexity video encoder. Experimental results indicate that the proposed control method provides better visual and PSNR performance than the existing TMN8 rate control method.

Interval arithmetic is able to be applied when we include the ranges of various functions. When we include them applying the interval arithmetic, the serious problem that the widths of the range inclusions increase extremely exists. In range inclusion of polynomials particularly, Horner's method and Alefeld's method are well known as the conventional methods which mitigates this problem. The purpose of this paper is to propose the new methods which are able to mitigate this problem more efficiently than the conventional methods. And in this paper, we show and compare the efficiencies of the new methods by some numerical examples.

The bi-level digital video, because of its simplicity and compactness, can be utilized to provide for a quick and faithful preview of its original content. The proposed bi-level digital video compression technique exploits the context-based probabilistic estimation model towards adaptive pixel prediction which can be used towards generating residual image frames which may then be Run-Length-Rice coded. Towards promoting error-resiliency and random-access, each bi-level digital video frame may be typed into either intra- or inter- picture format. The proposed technique can be seen, in comparison to existing JBIG compression technologies in simulation runs, to provide added temporal redundancy removal.

In this letter, we propose an enhanced time-based registration method and analyze the performance numerically. In the analysis, we assume Poisson call arrival distribution and exponential cell resident time. The performance of the enhanced time-based registration method is compared with the performance of the original time-based registration method. In the comparisons, we see that in a certain range of parameters, the enhanced time-based registration method has better performance.

One of the key issues in the next generation Internet is end-to-end Quality of Service (QoS) provisioning for real-time applications. The Differentiated Services (DiffServ) architecture offers a scalable alternative to provide QoS in the Internet. However, within this architecture, an efficient scheduling mechanism is still needed to ensure such QoS guarantees. In this paper, scheduling mechanism for supporting QoS differentiation among multiple traffic classes in IP differentiated services networks is studied. A scheduling algorithm called Multiclass Efficient Packet Fair Queueing (MEPFQ) is proposed that enables fair bandwidth sharing while supporting better bounds on end-to-end network delay for QoS-sensitive applications such as voice over IP (VoIP) within the DiffServ framework. The mechanism allows to create service classes and assign proportional weights to such classes efficiently according to their resource requirements. Besides, MEPFQ tries to ensure that packets from low priority class will not be starved even under extreme congestion cases. The results from the simulation studies show that the mechanism is able to ensure both the required end-to-end network delay bounds and bandwidth fairness for QoS-sensitive applications based on the specified service weights under various traffic and network conditions. Another important aspect of the MEPFQ algorithm is that the scheme has lower implementation complexity, along with scalability to accommodate the growing traffic flows at the core routers of high-speed Internet backbone.

We have shown that a photonic sensor can be used as an electric-field probe for planar near-field measurements of X-band antennas. Because an antenna on the photonic sensor is small (about 0.1 λ) compared to the wavelength, the photonic sensor can directly measure the amplitude and the phase of the electric field close (about 0.3 λ) to the apertures of antennas without disturbing the electric field to be measured. Therefore we can obtain the antenna pattern by transforming the measured electric field without probe compensation. To verify the merits of the photonic sensor, we have evaluated the antenna patterns of a standard gain horn antenna and a microstrip array antenna at 9.41 GHz. Comparing the results obtained using the photonic sensor with those obtained using the conventional open-ended waveguide probe and other methods, we have shown that the antenna patterns agree with each other within 1 dB over wide ranges of directivity.

Measuring and modeling network traffic is of key importance for the traffic engineering of IP networks, due to the growing diversity of multimedia applications and the need to efficiently support QoS differentiation in the network. Several recent measurements have shown that Internet traffic may incorporate long-range dependence and self-similar characteristics, which can have significant impact on network performance. Self-similar traffic shows variability over many time scales, and this behavior must be taken into account for accurate prediction of network performance. In this paper, we propose a new parameter fitting procedure for a superposition of Markov Modulated Poisson Processes (MMPPs), which is able to capture self-similarity over a range of time scales. The fitting procedure matches the complete distribution of the arrival process at each time scale of interest. We evaluate the procedure by comparing the Hurst parameter, the probability mass function at each time scale, and the queuing behavior (as assessed by the loss probability and average waiting time), corresponding to measured traffic traces and to traces synthesized according to the proposed model. We consider three measured traffic traces, all exhibiting self-similar behavior: the well-known pOct Bellcore trace, a trace of aggregated IP WAN traffic, and a trace corresponding to the popular file sharing application Kazaa. Our results show that the proposed fitting procedure is able to match closely the distribution over the time scales present in data, leading to an accurate prediction of the queuing behavior.

Using the Proportional Integral Derivative (PID) principle of classical feedback control theory, this paper develops two general congestion control algorithms for routers implementing Active Queue Management (AQM) while supporting TCP/IP traffic flows. The general designs of non-interacting (N-PID) and interacting (I-PID) congestion control algorithms are tailored for practical network scenarios using the Ziegler-Nichols guidelines for tuning such controllers. Discrete event simulations using ns are performed to evaluate the performance of an existing F-PID and new N-PID and I-PID algorithms. The performance of N-PID and I-PID is compared mutually as well as with the F-PID algorithm. It reveals that N-PID and I-PID have higher speed of response but lower stability margins than F-PID. In general the accurate following of the target queue size by the PID principle congestion control algorithms, while providing high link utilization, low loss rate and low queuing delays, is also demonstrated.

This paper proposes a new supply current test method for detecting floating gate defects in CMOS ICs. In the method, unusual increase of the supply current caused by defects is promoted by superposing an AC component on the DC power supply. Feasibility of the test is examined by some experiments on four DUTs with an intentionally caused defect. The results showed that our method could detect clearly all the defects, one of which may be detected by neither any functional logic test nor any conventional supply current test.

Artificial electromagnetic structures have significantly broadened the range of wave propagation phenomena available. In particular, it has been shown that metamaterials can be constructed for which the index-of-refraction is negative over a finite band of frequencies. In this paper, we present the design, fabrication and characterization of a metamaterial that exhibits negative refraction. The metamaterial design we explore is anisotropic in the plane of propagation. Based on our analysis and supporting simulations and measurements, we demonstrate that for the geometry considered, the anisotropic metamaterial has the identical negative refraction properties as would an isotropic negative index metamaterial.

In this paper, test time reduction for IDDQ testing is discussed. Although IDDQ testing is known to be effective to detect faults in CMOS circuit, test time of IDDQ testing is larger than that of logic testing since supply current is measured after a circuit is in its quiescent state. It is shown by simulation that test time of IDDQ test mostly depends on switching current. A procedure to modify test vectors and a procedure to arrange test vectors are presented for reducing the test time of IDDQ testing. A test sequence is modified such that switching current quickly disappears. The procedure utilizes a unit delay model to estimate the time of the last transition of logic value from L to H in a circuit. Experimental results for benchmark circuits show the effectiveness of the procedure.

This paper describes a method of test data compression for a given test set using statistical encoding. In order to maximize the effectiveness of statistical encoding, the method first converts some specified input values in the test set to unspecified ones without losing fault coverage, and then reassigns appropriate logic values to the unspecified inputs. Experimental results for ISCAS-89 benchmark circuits show that the proposed method can on the average reduce the test data volume to less than 25% of that required for the original test set.

Low-loss optical coupling structures between photonic crystal waveguides and channel waveguides were investigated. It was emphasized that impedance matching of guided modes of those waveguides, as well as field-profile matching, was essential to achieving the low-loss optical coupling. We developed an impedance matching theory for Bloch waves, and applied it to designing the low-loss optical coupling structures. It was demonstrated that the optical coupling loss between a photonic crystal waveguide and a Si-channel waveguide was reduced to as low as 0.7 dB by introducing an interface structure for impedance matching between the two waveguides.

Advances in ILP techniques enable strict consistency models to relax memory order through speculative execution of memory operations. However, ordering constraints still hinder the performance because speculatively executed operations cannot be committed out of program order for the possibility of mis-speculation. In this paper, we propose a new technique which allows memory operations to be non-speculatively committed out of order without violating consistency constraints. Consistency constraints are guaranteed through delaying the coherence requests. The proposed technique also improves the performance of spin lock primitives such as TTS lock or MCS lock. Through delaying early acquire requests, the lock transfer time can be improved when there is high contention for a lock.