The (k + δ)-edge-connectivity augmentation problem for a specified set of vertices ((k + δ)ECA-SV) is defined as follows: "Given an undirected graph G =(V,E), a specified set of vertices Γ V, a subgraph G ′=(V,E ′) with λ(Γ;G ′) = k of G and a cost function c: E Z+ (nonnegative integers), find a set E* E - E ′of edges, each connecting distinct vertices of V, of minimum total cost such that λ(Γ;G″) k + δ for G"=(V,E ′∪E*)," where λ(Γ;G″) is the minimum value of the maximum number of edge disjoint paths between any pair of vertices in Γ of G". The paper proposes an O(Δ+|V||E|) time 2-approximation algorithm FSAR for (k + 1)ECA-SV with a restriction λ(V;G ′) = λ(Γ;G ′), where Δ is the time complexity of constructing a structural graph of a given graph G ′.

Recent studies show that several FFT-based high-accuracy frequency estimation methods achieve very good performance. In this letter, we select three methods, which are the zero-padding, weighted multipoint interpolated DFT, and phase difference approximation respectively, and discuss the window selection for each method. Experiments show that the window selection primarily depends on the signal-to-noise ratio (SNR). As a result, the optimal window selection for each method and, reversely, the optimal selection of the estimation method for a specific window are discussed as a function of SNR. Consideration on the computational load and the resolution problem is also briefly discussed.

In high-capacity optical WDM networks, the failure of a network component such as a fiber link may disconnect many optical lightpaths, leading to severe disruption in network services. Therefore it is imperatively important to provide fast and full protection against any failure in optical WDM networks. The method of pre-configured protection cycles (p-cycles) is very attractive for design of survivable optical networks. So far p-cycle approach has been extensively studied for design of survivable optical networks where traffic demand is static. In this paper, we first briefly describe our recently proposed p-cycle design heuristic and then show how to apply this heuristic to optical networks where traffic demand is dynamically changing. We consider three different strategies to configure dynamic p-cycles for dynamic traffic demands, and compare their performance in terms of blocking probability and computational time.

A new interacting multiple model (IMM) algorithm using intelligent input estimation (IIE) is proposed for maneuvering target tracking. In the proposed method, the acceleration level for each sub-model is determined by IIE-the estimation of the unknown target acceleration by a fuzzy system using the relation between the residuals of the maneuvering filter and the non-maneuvering filter. The genetic algorithm (GA) is utilized to optimize a fuzzy system for a sub-model within a fixed range of target acceleration. Then, multiple models are represented as the acceleration levels estimated by these fuzzy systems, which are optimized for different ranges of target acceleration. In computer simulation for an incoming anti-ship missile, it is shown that the proposed method has better tracking performance compared with the adaptive interacting multiple model (AIMM) algorithm.

The switchable dual-wavelength and wavelength-con-verted nonreturn-to-zero-to-return-to-zero (NRZ-to-RZ) data transformation is demonstrated by externally seeding a synchronously sinusoidal-modulated laser diode with an optical pseudorandom bit sequence data at 1 Gbps. A maximum wavelength tuning range of 30 nm with an SMSR of greater than 36 dB is obtained. 1 Gbps on/off keying of single-mode RZ data pulse-train generated by externally seeding synchronously sinusoidal-modulated laser diode is demonstrated.

We propose guidelines for LSI-chip design, taking the within-die variations into consideration, and for process quality improvement to suppress the variations. The auto-correlation length, λ, of device variation is shown to be a useful measure to treat the systematic variations in a chip. We may neglect the systematic variation in chips within the range of λ, while σ2 of the systematic variation must be added to σ2 of the random variation outside the λ. The random variations, on the other hand, exhibit complete randomness even in the closest pair transistors. The mismatch variations in transistor pairs were enhanced by 1.41(=) compared with the random variations in single transistors. This requires careful choice of gate size in designing a transistor pair with a minimum size, such as transfer gates in an SRAM cell. Poly-Si gate formation is estimated to be the most important process to ensure the spatial uniformity in transistor current and to enhance circuit performance. Large relative variations are observed for the contact to p+ diffusion, via1 (M1-M2), and via2 (M2-M3) among parameter variations in passive elements. The standard deviations for random variations in via1 and via2 are noticeably widespread, indicating the importance of the via resistance control in BEOL. The spatial frequency power spectrum for within-die random variations is confirmed experimentally, as uniform ('white') with respect to the spatial frequency. To treat the large 'white random noise,' the least-square method with a 4th-order polynomial exhibits a best efficiency as a fitting function for decomposing the raw variation data into systematic part and random part.

A new inductance extraction technique of spiral inductor from measurement fixture is presented. We propose a scalable expression of parasitic inductance for interconnects, and design consideration of test structure accommodating spiral inductor. The simple expression includes mutual inductance between the interconnects with high accuracy. The formula matches a commercial field solver inductance values within 1.4%. The layout of the test structure to reduce magnetic coupling between the spiral and the interconnects allows us to extract the intrinsic inductance of spiral more accurately. The proposed technique requires neither special fixture used for measurement-based method nor skilled worker for precise extraction with the analytical technique used.

The history of forward error correction in optical communications is reviewed. The various types of FEC are classified as belonging to three generations. The first generation FEC represents the first to be successful in submarine systems, when the use of RS(255, 239) became widespread as ITU-T G.975, and also as G.709 for terrestrial systems. As WDM systems matured, a quest began for a stronger second generation FEC. Several types of concatenated code were proposed for this, and were installed in commercial systems. The advent of third-generation FEC opened up new vistas for the next generation of optical communication systems. Thanks to soft decision decoding and block turbo codes, a net coding gain of 10.1 dB has been demonstrated experimentally. That brought us a number of positive impacts on existing systems. Each new generation of FEC was compared in terms of the ultimate coding gain. The Shannon limit was discussed for hard or soft decision decoding. Several functionalities employing the FEC framing were introduced, such as overall wrapping by the FEC frame enabling the asynchronous multiplexing of different clients' data. Fast polarization scrambling with FEC was effective in mitigating polarization mode dispersion, and the error monitor function proved useful for the adaptive equalization of both chromatic dispersion and PMD.

Many immersive displays developed in previous researches are strongly influenced by the design concept of the CAVE, which is the origin of the immersive displays. In the view of human-scale interactive system for virtual environment (VE), the existing immersive systems are not enough to use the potential of a human sense further extent. The displays require more complicated structure for flexible extension, and are more restrictive to user's movement. Therefore we propose a novel multi-projector display for immersive VE with haptic interface for more flexible and dynamic interaction. The display part of our system named "D-vision" has a hybrid curved screen which consist of compound prototype with flat and curve screen. This renders images seamlessly in real time, and generates high-quality stereovision by PC cluster and two-pass technology. Furthermore a human-scale string-based haptic device will integrate with the D-vision for more interactive and immersive VE. In this paper, we show an overview of the D-vision and technologies used for the human-scale haptic interface.

In this letter, we propose "Torus Ring", which is a modified version of 2-level hierarchical ring. The Torus Ring has the same complexity as the hierarchical rings, since the only difference is the way it connects the local rings. It has an advantage over the hierarchical ring when the destination of a packet is the adjacent local ring, especially to the backward direction. Although we assume that the destination of a network packet is uniformly distributed across the processing nodes, the average number of hops in Torus Ring is equal to that of the hierarchical ring. However, the performance gain of the Torus Ring is expected to increase, due to the spatial locality of the application programs in the real parallel programming environment. In the simulation results, latencies of the interconnection network are reduced by up to 19%, with moderate ring utilization ratios.

Fundamentals of parametric processing in highly nonlinear optical fiber are reviewed. Experimental procedures necessary for construction of one- and two-pump parametric amplifier architectures are described. Pump phase broadening, dispersion fluctuation and birefringence form basic impairment mechanisms in fiber parametric devices and are analyzed in two-pump parametric devices. Parametric signal processing is introduced with specific applications in all-optical regeneration, band conjugation, multicasting, packet switching and signal distortion reversal.

This paper reviews the approximation principle of Physical Optics in view of diffraction theory. Two key error factors are identified for PO, that is, 1) errors in edge diffraction coefficients and 2) fictitious penetrating rays. Improved methods named PO-AF and PTD-AF are proposed as the methods which suppress the fictitious penetrating rays from PO and PTD respectively. In deep shadow regions of the reflector antennas, PO-AF and PDT-AF approach to PO-EEC and UTD respectively, while the continuity is assured. The effectiveness is numerically demonstrated for two dimensional scatterers.

We investigate the error exponent in the lossy source coding with a fidelity criterion. Marton (1974) established a formula of the reliability function for the stationary memoryless source with finite alphabet. In this paper, we consider a stationary memoryless source assuming that the alphabet space is a metric space and not necessarily finite nor discrete. Our aim is to prove that Marton's formula for the reliability function remains true even if the alphabet is general.

In this paper, the previously introduced periodic Fourier transform concept is extended to a two-dimensional case. The relations between the periodic Fourier transform, harmonic series representation and Fourier integral representation are also discussed. As a simple application of the periodic Fourier transform, the scattering of a scalar wave from a finite periodic surface with weight is studied. It is shown that the scattered wave may have an extended Floquet form, which is physically considered as the sum of diffraction beams. By the small perturbation method, the first order solution is given explicitly and the scattering cross section is calculated.

A GaInAs/InP multiple quantum well (MQW)-based wavelength demultiplexer composed of a waveguide array in which the refractive index varies across the array yielded successful results of wavelength demultiplexing and optical deflection. Since optical path length differences between waveguides in the array are achieved through refractive-index differences controlled by the SiO2 mask design in selective metal-organic vapor phase epitaxy (MOVPE), a straight waveguide grating can be formed with reduced optical propagation losses. A straight waveguide array device with a 1.4% refractive-index difference was fabricated. The fabrication of a preliminary wavelength demultiplexer was also achieved, for which a wavelength separation with an approximately 25 nm spacing and free spectral range (FSR) of approximately 100 nm were obtained. Moreover, an optical deflector was investigated and primitive deflection was achieved at 1460 and 1490 nm incident wavelengths.

One of the most challenging tasks in computer graphics and cyberworlds is the realistic animation of the behavior of virtual agents emulating human beings and evolving within virtual 3D worlds. In a previous paper, the authors presented a new, sophisticated behavioral system that allows the agents to take intelligent decisions by themselves. A central issue of this process is the adequate choice of appropriate mechanisms for goal selection. This is actually the aim of the present contribution. In this paper a new scheme for goal selection is described. According to it, the goal's priority is calculated as a combination of different agent's internal states (given by mathematical functions also described in this paper) and external factors (which will determine the goal's feasibility). The architecture of the goal selection module as well as its simulation flow are also analyzed in this paper. Finally, the excellent performance of this new scheme is enlightened by means of a simple yet illustrative example.

We proposed a novel structure that improved the linear characteristics of electroabsorption modulator (EAM) with composite quantum-wells as an absorption core layer. We fabricated three types of EAM's whose active cores were 8 nm thick, 12 nm thick and a composite core with 8 nm thick and 12 nm thick quantum-well (QW), respectively. The transfer functions of EAM's were investigated and their third-order inter-modulation distortion (IMD3) was obtained by calculation. The spurious free dynamic range (SFDR) was measured and compared with three types of QW. The linearity of the device with composite quantum-well showed a large enhancement in SFDR by 9.3 dBHz2/3 in TE mode and 7.0 dBHz2/3 in TM mode compared with the conventional EAM.

Press-induced long-period fiber gratings exhibiting strong core-to-cladding mode coupling were formed in photonic crystal fiber. Only one resonance peak was observed over a 600 nm spectral range and the resonant wavelength was tuned over the whole range by tilting a groove plate before pressing the fiber. The resonant wavelength decreased with increasing periodicity of the grating, which was opposite to the trend of the step-index conventional optical fiber. Meanwhile, the resonant wavelength increased with increasing the ambient refractive index, which was also opposite to that of the conventional optical fiber.

This paper reports our study of how to gain consistency of states in a ball-game typed Distributed Virtual Environment (DVE) with lag, in peer-to-peer (P2P) architecture. That is, we are studying how to reduce in real-time the difference of states between the participating terminals in a virtual ball game caused by transmission lag or update interval. We are also studying how to control shared objects in real-time in a server-less network architecture. Specifically, a priority field called Allocated Topographical Zone (AtoZ) is used in P2P for DVE. By implementing this function, each terminal can compute which avatar holds the ownership of a shared object by calculating mutually the state of the local avatar predicted by the remote terminals. The region for ownership determined by AtoZ allows an avatar to access and control an object dominantly, so that a geometrical property is dynamically changed depending upon the relative arrangement between the object and avatars. Moreover considering the critical case, defined as inconsistent phenomena between the peers, caused by the network latency, a stricter ownership determination algorithm, called dead zone is introduced. By using these protocols in combination, a robust and effective scheme is achieved for a virtual ball game. As an example of the application, a real-time networked doubles air-hockey is implemented for evaluation of the influence of these protocols on interactivity and on consistency.

In the Reconfigurable System-On-a-Chip (RSOC), an FPGA core is embedded to improve the design flexibility of SOC. In this paper, we demonstrate that the embedded FPGA core is also feasible for use in implementing the proposed hybrid pattern Built-In Self-Test (BIST) in order to reduce the test cost of SOC. The hybrid pattern BIST, which combines Linear Feedback Shift Register (LFSR) with the proposed on-chip Deterministic Test Pattern Generator (DTPG), can achieve not only complete Fault Coverage (FC) but also minimum test sequence by applying a selective number of pseudorandom patterns. Furthermore, the hybrid pattern BIST is designed under the resource constraint of target FPGA core so that it can be implemented on any size of FPGA core and take full advantage of the target FPGA resource to reduce test cost. Moreover, the reconfigurable core-based approach has minimum hardware overhead since the FPGA core can be reconfigured as normal mission logic after testing such that it eliminates the hardware overhead of BIST logic. Experimental results for ISCAS 89 benchmarks and a platform FPGA chip have proven the efficiency of the proposed approach.