A chemical shift MR method which utilizes a oscillating gradient field is presented in this paper. Frequency modulation resulting from oscillating a gradient field spreads the spectrum that contains both chemical shift and spatial information, over a wide frequency range by using a large modulation factor in FM. The chemical shift spectrum resides within every frequency band segmented by the modulation frequency ωm. The spectral elements gathered from all such frequency segments for a chemical shift frequency contain the spatial image of that particular chemical shift frequency, despite the distortion introduced by a series of the Bessel functions acting as a point spread function. A sum of several Bessel functions of the first kind Jn(. ) is used to approximate the deconvolution process, since the sum staggered with respect to n has a desirable peaking property useful in deconvolution. This leads to devise a new image reconstruction algorithm based on the simple moving average over the spatial coordinate for which the oscillating gradient is applied. Furthermore, the number of echo measurements necessary for an image size of N N is reduced from N2 of the spin echo chemical shift imaging down to N by this method. Simulation results supporting the validity of this method are also presented in this paper.

Autonomous distributed scheduling is based on the autonomous decentralized optimization and recently focused as one of flexible scheduling techniques which can more cope with dynamically changing situation than traditional ones. This paper proposes an autonomous distributed scheduling scheme for the parallel machine scheduling problem. Through computer simulation, we observe that our proposed scheme can more quickly reduce the total deadline over-time than one in the literature and can adapt flexibly to unusual situation (addition of jobs).

This paper aims at improving effectiveness of previously proposed hybrid priority lists, {L*i=LdLsi}, that are applied in nonpreemptive 2-processor scheduling of general acyclic SWITCH-less program nets, where Ld and Lsi are dynamic and static priority lists respectively. Firstly, we investigate the effectiveness of Ld through experiments. According to the experimental results, we reconstruct Ld to propose its improved list L1d. Then analyzing the construction methodology of the static priority lists {Lsi}, we propose a substituted list L2d by taking into account of the factor: remaining firing numbers of nodes. Finally, we combine a part of L1d and L2d to propose a new priority list L**. Through scheduling simulation on 400 program nets, we find the new priority list L** can generate shorter schedules, close to ones of GA (Genetic Algorithm) scheduling that has been shown exceedingly effective but costing much computation time.

Most scheduling applications have been classified into NP-complete problems. This fact implies that an optimal solution for a large scheduling problem is extremely time-consuming. A number of schemes are introduced to solve NP-complete scheduling applications, such as linear programming, neural network, and fuzzy logic. In this paper, we demonstrate a new approach, fuzzy Hopfield neural network, to solve the scheduling problems. This fuzzy Hopfield neural network approach integrates fuzzy c-means clustering strategies into a Hopfield neural network. In this investigation, we utilizes this new approach to demonstrate the feasibility of resolving a multiprocessor scheduling problem with no process migration, limited resources and constrained times (execution time and deadline). In the approach, the process and processor of the scheduling problem can be regarded as a data sample and a cluster, respectively. Then, an appropriate Lyapunov energy function is derived correspondingly. The scheduling results can be obtained using a fuzzy Hopfield neural network clustering technique by iteratively updating fuzzy state until the energy function gets minimized. To validate our approach, three scheduling cases for different initial neuron states as well as fuzzification parameters are taken as testbed. Simulation results reveal that imposing the fuzzy Hopfield neural network on the proposed energy function provides a sound approach in solving this class of scheduling problems.

This paper is concerned with fuzzy modeling in some reduction methods of inference rules with gradient descent. Reduction methods are presented, which have a reduction mechanism of the rule unit that is applicable in three parameters--the central value and the width of the membership function in the antecedent part, and the real number in the consequent part--which constitute the standard fuzzy system. In the present techniques, the necessary number of rules is set beforehand and the rules are sequentially deleted to the prespecified number. These methods indicate that techniques other than the reduction approach introduced previously exist. Experimental results are presented in order to show that the effectiveness differs between the proposed techniques according to the average inference error and the number of learning iterations.

In this paper, we report on design and fabrication of the pipelined digital correlator (PDC) for the opto-electronic discrete correlation processor (OEDCP). The OEDCP consists of optical fan-in and fan-out interconnection systems and several number of PDC's with optical I/O ports. The OEDCP achieves high processing performance with sophisticated combination of optics and electronics. We design and fabricate a prototype of the PDC which is the processing engine of the OEDCP. For the prototype, the pixel number of the input and the output images is 88 and that of the kernel is 33. The designed chip is composed of approximately 10,000 transistors. Operation of the fabricated chip was verified using test vectors.

The features of the negative resistance in common source and common gate FET configurations for wideband VCO are studied. They are also explained by the simplified three-capacitor model. A design procedure is then developed. The results are applied to a design of wide band oscillator at the several gigahertz region.

This paper proposes an extended variant of the method by Brickel et al. for multiple scalar multiplication over an elliptic curve. In smartcard environments, the proposed method is superior to conventional methods. In particular, when the typical number of bases t=2, the proposed method is four times faster than the simultaneous multiple exponentiation method, a well known fast method for multiple scalar multiplication. Furthermore, the proposed method can change the amount of time and memory to fit various platform environment (e.g., personal computers as rich ones or mobile devices such as smartcards as poor ones) by adjusting the division bit width (division unit).

A 64-bit architecture for an embedded processor targeted for next-generation digital consumer products has been developed. It has dual-mode instruction sets and is optimized for high multimedia performance, provided by SIMD/floating-point vector instructions in 32-bit length ISA, and small code size, provided by a conventional 16-bit length ISA. Large register files, (6464b and 6432b), a split-branch mechanism, and virtual cache are also adopted in the architecture. A 714MIPS/9.6 GOPS/400 MHz processor core with the 64-bit architecture and a system LSI containing the core are developed using 0.15-µm technology. The LSI includes a 3.2 GB/sec high-bandwidth on-chip bus, a high-speed DRAM interface, a SRAM/Flash/ROM/Multiplexed-bus interface, and a 66 MHz PCI interface that provide the performance required for next-generation multimedia applications.

Wire delays, instead of gate delays, are moving into dominance in modern VLSI design. Current synchronous processors have the critical path not in the ALU function but in the cache access. Since the cache performance enhancement is limited by the memory access delay which mainly consists of wire delays, a reduction in gate delays may no longer imply any enhancement in processor performance. To solve this problem, this paper presents a novel architecture, called the Cascade ALU. The Cascade ALU allows super-scalar processors with future technologies to move the critical path into the ALU part. Therefore the Cascade ALU can enjoy the expected progress in future device speed. Since the delay of the Cascade ALU varies depending on the executed instructions, an asynchronous system is shown to be suitable for implementing the Cascade ALU. However an asynchronous system may have a large handshake overhead, this paper also presents an asynchronous Fine Grain Pipeline technique that hides the handshake overhead. Finally, this paper presents results of performance and area evaluation for an asynchronous implementation of the cascade ALU. The results show that the cascade ALU architecture has a good performance scalability on the reduction of the ALU latency and imposes little area penalty compared with current synchronous processors.

Simple and scalable device-modeling techniques for inductors and capacitors are described. All model parameters are calculated from geometric parameters of the device, process parameters of the technology, and a substrate resistance parameter. Modeling techniques for other devices, such as resistors, varactor diodes, pads and MOSFETs, are also described. Some simulation results using the proposed device-modeling techniques are compared with measured results and they indicate adequacy of the proposed device-modeling techniques.

A low-voltage 6-GHz-band monolithic LC-tank VCO has been fabricated using 0.2-µm CMOS/SIMOX process technology. The VCO features a tuning-range switching technique to achieve a wide tuning range. The output frequency range is between 5.71 and 6.21 GHz owing to the tuning-range switch. With the tuning-range switch on or off, the phase noise is about -100 dBc/Hz at 1-MHz offset and about -120 dBc/Hz at 10-MHz offset frequency at the supply voltage of 2 V.

This paper examines similarities between the Decision Diffie-Hellman (DDH) assumption and the Quadratic Residuosity (QR) assumption. In addition, we show that many cryptographic protocols based on the QR assumption can be reconstructed using the DDH assumption.

In this paper, we attempt to construct practical secret sharing schemes, which scheme has smaller share size and can detect cheating with high probability. We define two secure ramp schemes, secure ramp scheme and strongly secure ramp scheme. Then, we propose two constructions of secure ramp scheme. These schemes both have small share size and the cheating can be detected with high probability. So, they are practical secret sharing schemes.

In this paper, we present a computer-aided diagnosis (CAD) system to automatically detect lung cancer candidates at an early stage using a present and a past helical CT screening. We have developed a slice matching algorithm that can automatically match the slice images of a past CT scan to those of a present CT scan in order to detect changes in the lung fields over time. The slice matching algorithm consists of two main process: the process of extraction of the lungs, heart, and descending aorta and the process of matching slices of the present and past CT images using the information of the lungs, heart, and descending aorta. To evaluate the performance of this algorithm, we applied it to 50 subjects (total of 150 scans) screened between 1993 and 1998. From these scans, we selected 100 pairs for evaluation (each pair consisted of scans for the same subject). The algorithm correctly matched 88 out of the 100 pairs. The slice images for the present and past CT scans are displayed in parallel on the CRT monitor. Feature measurements of the suspicious regions are shown on the relevant images to facilitate identification of changes in size, shape, and intensity. The experimental results indicate that the CAD system can be effectively used in clinical practice to increase the speed and accuracy of routine diagnosis.

The first important step in pre-processing data for 3D virtual colonoscopy requires careful segmentation of a complicated shaped colon. We describe an automatic colon segmentation method with a new patient-friendly bowel preparation scheme. This new bowel preparation makes the segmentation more appropriate for digitally removing undesirable remains in the colon. With the aim of segmenting the colon accurately, we propose two techniques which can solve the partial-volume-effect (PVE) problem on the boundaries between low and high intensity regions. Based on the features of the adverse PVE voxels on the gas and fluid boundary inside the colon, our vertical filter eliminates these PVE voxels. By seriously considering the PVE on the colon boundary, our gradient-magnitude-based region growing algorithm improves the accuracy of the boundary. The result of the automatic colon segmentation method is illustrated with both extracted 2D images from the experimental volumetric abdominal CT datasets and a reconstructed 3D colon model.

We introduce efficient algorithms for scalar multiplication on elliptic curves defined over FP. The algorithms compute 2k P directly from P, where P is a random point on an elliptic curve, without computing the intermediate points, which is faster than k repeated doublings. Moreover, we apply the algorithms to scalar multiplication on elliptic curves, and analyze their computational complexity. As a result of their implementation with respect to affine (resp. weighted projective) coordinates, we achieved an increased performance factor of 1.45 (45%) (resp. 1.15 (15%)) in the scalar multiplication of the elliptic curve of size 160-bit.

This paper newly formalizes some notions of security for probabilistic public-key encryption schemes. The framework for these notions was originally presented in the work by Bellare et al., in which they consider non-malleability and indistinguishability under chosen-plaintext attack, non-adaptive chosen-ciphertext attack and adaptive chosen-ciphertext attack. This paper extends the results of Bellare et al. by introducing two goals, equivalence undecidability and non-verifiability under the above three attack models. Such goals are sometimes required in electronic voting and bids systems. It is shown that equivalence undecidability, non-verifiability and indistinguishability are all equivalent under the three attack models.

In this paper, first, we propose two of the high rate methods based on Morii-Kasahara cryptosystem. Method A-I is based on Schalkwijk algorithm. Method A-II is based on the extended Schalkwijk algorithm, which is proposed in this paper. We then show that these proposed methods can yield a higher rate compared with ElGamal cryptosystem. Next, we also propose two methods for a fast encryption by dividing the message vector into several pieces. Regarding each of the divided vectors as an index, we can realize a fast transformation of the index into a limited weight vector. In Method B-I, Schalkwijk algorithm is used for the fast transformation. In Method B-II, the fast transformation is realized with the method of table-lookup. These methods can realize a faster encryption than Method A-I, Method A-II and Morii-Kasahara cryptosystem. The security of these proposed methods are based on the security of Morii-Kasahara cryptosystem.

As far as the knowledge of authors, the rigorous security of Okamoto-Tanaka identity-based key exchange scheme was shown in [4] for the first time since its invention. However, the analysis deals with only the passive attack. In this paper, we give several models of active attacks against the scheme and show the rigorous security of the scheme in these models. We prove several relationships among attack models, including that (1) breaking the scheme in one attack model is equivalent to breaking the RSA public-key cryptosystem and (2) breaking the scheme in another attack model is equivalent to breaking the Diffie-Hellman key exchange scheme over Zn. The difference of the complexity stems from the difference of the timing of dishonest party's sending out and receiving messages.