The square-law characteristics of MOSFET in the saturation region have a parameter of threshold voltage VT. However, it introduces some complexities to the circuit design since it depends on kinds of MOS technology and cannot be controlled easily. In this paper, we show an equivalent MOSFET cell which has VT-programming capability and some application instances based on it. The simulation is carried out using CMOS 0.8 µm n-well technology and the results have shown the feasibility of the proposed structure.

The sequence-pair was proposed as a representation method of block placement to determine the densest possible placement of rectangular modules in VLSI layout design. A method of achieving bottom left corner packing in O(n2) time based on a given sequence-pair of n rectangles was proposed using horizontal/vertical constraint graphs. Also, a method of determining packing from a sequence-pair in O(n log n) time was proposed. Another method of obtaining packing in O(n log log n) time was recently proposed, but further improvement was still required. In this paper, we propose a method of obtaining packing via the Q-sequence (representation of rectangular dissection) in O(n+k) time from a given sequence-pair of n rectangles with k subsequences called adjacent crosses, given the position of adjacent crosses and the insertion order of dummy modules into adjacent crosses. The position of adjacent crosses and insertion order of dummy modules can be obtained from a sequence-pair in O(n+k) time using the conventional method. Here, we prove that arbitrary packing can be represented by a sequence-pair, keeping the value of k not more than n-3. Therefore, we can determine packing from a sequence-pair with k of O(n) in linear time using the proposed method and the conventional method.

A family F of min-wise independent permutations is known to be a useful tool of indexing replicated documents on the Web. We say that a family F of permutations on {0,1,. . . ,n-1} is min-wise independent if for any X {0,1,. . . ,n-1} and any x X, Pr[min {π(X)} = π(x)]= ||X||-1 when π is chosen uniformly at random from F, where ||A|| is the cardinality of a finite set A. We also say that a family F of permutations on {0,1,. . . ,n-1} is d-wise independent if for any distinct x1,x2,. . . ,xd {0,1,. . . , n-1} and any distinct y1,y2,. . . ,yd {0,1,. . . , n-1}, Pr[i=1d π(xi) = π(yi)]= 1/{n(n-1) (n-d+1)} when π is chosen uniformly at random from F (note that nontrivial constructions of d-wise independent family F of permutations on {0,1,. . . ,n-1} are known only for d=2,3). Recently, Broder, et al. showed that any family F of pairwise (2-wise) independent permutations behaves close to a family of min-wise independent permutations, i.e., for any X {0,1,. . . ,n-1} such that 3 ||X||=k n-2 and any x X, (lower bound) Pr[min {π(X)}=π(x)] 1/{2(k-1)}; (upper bound) Pr[min {π(X)}=π(x)] O(1/k). In this paper, we extend these bounds to 3-wise independent permutation family and show that any family of 3-wise independent permutations behaves closer to a family of min-wise independent permutations, i.e., for any X {0,1,. . . ,n-1} such that 4 ||X||=k n-3 and any x X, (lower bound) Pr[min {π(X)}=π(x)] 1/{2(k-2)}- 1/{6(k-2)2}; (upper bound) Pr[min {π(X)}=π(x)] 2/k - 2/k + 1/(3kk).

A design method is proposed that yields the optimum remote pre-amplifier (RPRA) parameters considering cable repair, the results of include increased cable loss and insertion position uncertainty. The optimum RPRA location is given by the intersection point of optical SNR (OSNR) vs. RPRA location curves in two cases; the total cable repair loss is assumed to be inserted at the transmitter end and at the receiver end. This RPRA parameter gives the maximum OSNR in the worst loss insertion case by cable repair.

A traitor tracing scheme is a broadcast encryption scheme in which a provider can trace malicious authorized users who illegally gave their personal keys to unauthorized users. The conventional schemes have some problems; one of them is that there exists an upper bound on the sizes of keys to certify the security of the scheme against a collusion attack by many traitors, and so that the size of the header increases according to the increase of the bound. We shall propose a new traitor tracing scheme where the header size is independent of the number of traitors.

We examine diagnosis of processor array systems formed as two-dimensional grids, with boundaries, and either four or eight neighbors for each interior processor. We employ a parallel test schedule. Neighboring processors test each other and report the results. Our diagnostic objective is to find a fault-free processor or set of processors. The system may then be sequentially diagnosed by repairing those processors tested faulty according to the identified fault-free set. We establish an upper bound on the maximum number of faults that can be sustained without invalidating the test results under worst case conditions. We give test schedules and diagnostic algorithms that meet the upper bound as far as the highest order term. We compare these near optimal diagnostic algorithms to alternative algorithms--both new and already in the literature.

Layout design for analog circuits has historically been a time consuming, error-prone, manual task. Its complexity results not so much from the number of devices, as from the complex interactions among devices or with the operating environment, and also from continuous-valued performance specifications. This paper addresses the problem of device-level placement for analog layout in a non-traditional way. Different from the classic approaches--exploring a huge search space with a combinatorial optimization technique, where the cells are represented by means of absolute coordinates, being allowed to illegally overlap during their moves in the chip plane--this paper advocates the use of non-slicing topological representations, like (symmetric-feasible) sequence-pairs, ordered- and binary- trees. Extensive tests, processing industrial analog designs, have shown that using skillfully the symmetry constraints (very typical to analog circuits) to remodel the solution space of the encoding systems, the topological representation techniques can achieve a better computation speed than the traditional approaches, while obtaining a similar high quality of the designs.

Interest in service offerings at Ka-band (20/30 GHz) and above has been increasing recently, driven mainly by the availability at higher frequencies of wider bandwidths, which are attractive for many multimedia applications, for example. A dominant concern in implementing systems to operate in such bands is the severe propagation environment that exists on many transmission paths, such as paths in rainy climates or at low path elevation angles. Adequate understanding of the propagation environment is imperative in the design of economically viable telecommunication systems at these frequencies. A propagation measurement campaign that addressed many of these concerns was conducted in North America with 20.2 and 27.5 GHz radio beacons on NASA's Advanced Communications Technology Satellite (ACTS). Data were collected at seven locations over a continuous 5-year period to supply statistics of propagation impairments for a variety of climate types and path geometry. The primary results of the ACTS campaign as reported to date are reviewed. Studies performed to address related issues, including fading dynamics, site diversity and mobile-satellite performance, are also described. Elements of this paper were presented at the 2000 International Symposium on Antennas and Propagation (ISAP 2000), Fukuoka, Japan, 21-25 August 2000.

This paper explores how to extend the dependency pair technique for proving termination of higher-order rewrite systems. We show that the termination property of higher-order rewrite systems can be checked by the non-existence of an infinite R-chain, which is an extension of Arts' and Giesl's result for the first-order case. It is clarified that the subterm property of the quasi-ordering, used for proving termination automatically, is indispensable.

Chen et al., have proposed a new estimation method for the membership values in fuzzy sets. The proposed scheme takes input from empirical/experimental data, which reflect the expert's knowledge on the relative degree of belonging of the members, and then searches for the best fit membership values of the element. Through the estimation of the practical case (Sect. 3 in [1]) the algorithm suggests to normalize the estimated membership values if there is any among them more than one and change some condition to guarantee its positiveness. In this paper, we show how to use the same imposed condition to guarantee that the estimated membership values will be within the unit interval without normalization.

The analytic expression for the transmission spectrum of cascaded long-period fiber gratings is presented in a closed form. When several identical gratings are cascaded in-series with a regular distance, the transmission spectrum is revealed to have a series of regularly spaced peaks, suitable for multi-channel filters. The analytic solution is obtained by diagonalizing the transfer matrix of each grating unit that is composed of a single grating and a grating-free region between adjacent gratings. The spectrum of the device is simply described with the number of cascaded gratings and a single parameter that has the information of the phase difference between the modes. With the derived equation, the spectral behaviors of the proposed device are investigated. The intensity of each peak can be controlled by adjusting the strength of a single grating. The separation between adjacent gratings determines the spacing between the peaks. The finesse of the peaks can be increased by cascading more gratings. The derived analytic results are compared with the known results of paired gratings and phase-shifted gratings.

The analytic expression for the transmission spectrum of cascaded long-period fiber gratings is presented in a closed form. When several identical gratings are cascaded in-series with a regular distance, the transmission spectrum is revealed to have a series of regularly spaced peaks, suitable for multi-channel filters. The analytic solution is obtained by diagonalizing the transfer matrix of each grating unit that is composed of a single grating and a grating-free region between adjacent gratings. The spectrum of the device is simply described with the number of cascaded gratings and a single parameter that has the information of the phase difference between the modes. With the derived equation, the spectral behaviors of the proposed device are investigated. The intensity of each peak can be controlled by adjusting the strength of a single grating. The separation between adjacent gratings determines the spacing between the peaks. The finesse of the peaks can be increased by cascading more gratings. The derived analytic results are compared with the known results of paired gratings and phase-shifted gratings.

Arts and Giesl introduced the notion of dependency pairs, which gives effective methods for proving termination of term rewriting systems (TRSs). In this paper, we extend the notion to AC-TRSs, and introduce new methods for effectively proving AC-termination. It is impossible to directly apply the notion of dependency pairs to AC-TRSs. To avoid this difficulty, we introduce the notion of extended dependency pairs. Finally we define the AC-dependency pair and the AC-dependency chain. Furthermore, we propose approximated AC-dependency graphs, which is very useful for proving AC-termination in practice, using the approximation technique based on Ω-reduction and ΩV-reduction.

A K-band MMIC subharmonically pumped mixer integrating local oscillator (LO) amplifier has been developed. For up-converter application, it is necessary to reduce the leakage of second harmonic component of LO frequency to RF port, which is generated by nonlinear operation of LO amplifier. A quasi-lumped short-circuited stub using microstrip structure has been successfully applied to the MMIC mixer to enhance 2fLO-suppression. We propose a new configuration of a quasi-lumped short-circuited stub, which reduces the influence of parasitic elements of via-holes. The developed MMIC has a one-stage LO amplifier and it has shown about 10 dB-improvement of 2fLO-suppression compared to conventional configuration using a quarter-wavelength short-circuited stub.

The three dimensional (3D) packing problem is to arrange given rectangular boxes in a rectangular box of the minimum volume without overlapping each other. As an approach, this paper introduces the system of three sequences of the box labels, the sequence-triple, to encode the topology of the 3D-packing. The topology is the system of relative relations in pairs of boxes such as right-of, above, front-of, etc. It will be proved that the sequence-triple represents the topology of the tractable 3D-packings which is a 3D-packing such that there is an order of the boxes along which all the boxes are extracted one by one in a certain fixed direction without disturbing other remaining boxes. The idea is extended to the system of five ordered sequences, the sequence-quintuple. A decoding rule is given by which any 3D-packing is represented. These coding systems are applied to design heuristic algorithms by simulated annealing which search the codes for better 3D-packings. Experimental results were very convincing its usefulness as automated packing algorithms.

In this study, the influence of the location of ground plane on the noise (crosstalk) induced on twisted-pair-wire (TPW) by parallel wire is experimentally and theoretically discussed by paying attention to the capacitive coupling between TPW and parallel wire. The capacitance is obtained by applying the finite element method (FEM) to the calculation of electric field intensity. It is confirmed that the calculated results are in good agreement with the experimental results within 0.5 dB. It is concluded that the closer the TPW is to the ground plane, the smaller the induced noise on the TPW becomes.

Metallic pair lines transmitting high-frequency information signals above several tens MHz are often used without being twisted, as flat floor cable installed in buildings, ribbon-type cables installed in computer equipment, and traces in printed circuit boards. However, the conversion characteristics of untwisted unbalanced metallic pair lines connecting unbalanced circuits have not been investigated over a wide range of frequencies in the MHz region. First, we developed a method to estimate effective power conversion factors using a cascade connection of F matrices, where the unbalance in impedance and admittance of each pair line is distributed uniformly along the line. As a result some useful information was obtained about the balance-unbalance conversion characteristics of the effective power which can be used to suppress EMI phenomena in wiring, especially over several decades of high frequencies. Next, we attempted to apply the conversion characteristics of untwisted unbalanced pair lines obtained at frequencies below several MHz to techniques for searching for the return circuits of conductors installed in buildings. It was clarified experimentaly that the depth of the equivalent ground plane can be estimated by comparing the measured conversion values of TV feeder lines installed at the place being tested with reference values measured in advance on a copper plate .

This paper reports the evaluation results of the channel boron distribution in the deep sub-0.1 [µm] n-MOSFETs for the first time. It has been found that the boron depletion effect becomes dominant and the reverse short channel effect becomes less significant in the deep sub-0.1 [µm] n-MOSFETs. It has been also found that the sheet charge distribution responsible for the reverse short channel effect is localized within a distance of 100 [nm] from the source/drain-extension junction.

A method for locating the minimum eigenvalue and its corresponding eigenvector is considered. The core procedure utilized is the modified Rayleigh quotient iteration (MRQI). The convergence rate of the Rayleigh quotient iteration (RQI) is cubic. However, unfortunately, the RQI may not always locate the minimum eigenvalue. In this paper, a new MRQI that can always locate the minimum eigenpair is given. Based on the MRQI, a fast algorithm to locate minimum eigenpair will be proposed. This method has the following characteristics. First, it does not compute the inclusion interval. Second, it works for any Hermitian matrix as well as Toeplitz matrix. Third, it works on matrices having more than one minimum eigenvalue. Fourth, the numerical error of this method is very small. Fifth, it is attractively simple and fast. The convergence rate of this method is asymptotically cubic. MATLAB simulation results show that this method may outperform other methods. The term MRQI has been already used. Differences in several MRQI methods are discussed. Mathematical properties of the MRQI are investigated. This research can be effectively applied to diverse field of the signal processing including communication, because the signal space can be efficiently obtained.

Recent years have seen great advances in our understanding and modeling of the coupled diffusion of dopants and defects in silicon during integrated circuit fabrication processes. However, the ever-progressing shrinkage of device dimensions and tolerances leads to new problems and a need for even better models. In this review, we address some of the advances in the understanding of defect-mediated diffusion, focusing on the equations and parameters appropriate for modeling of dopant diffusion in submicron structures.