The authors proposed a switching beam slot array antenna with a 4-way Butler matrix. All are integrated in one substrate with post-wall waveguide techniques. The planar Butler matrix is realized by using short slot directional couplers (cross coupler). Experiments in 26GHz band confirmed the key operation of this antenna; almost identical four beams are switched to cover the total of horizontal 90-degree sector with equal angular spacing.

A virtual private network (VPN) service is likely to be used by customers as a replacement for networks constructed using private lines, and thus its functionality should include the performance guarantee provided to those customers. To provide guaranteed services, the network provider allocates appropriate capacities to multiple virtual backbone networks such that the underlying network can be shared among them. As VPN users are demanding reliable and dynamic allocation of capacities, recently the capacity resizing approach has been considered as a cost efficient way of providing virtual network services. We propose a new scheme for dynamic allocation of virtual link capacities. The allocated capacities are adjusted dynamically according to the users' requests such that their capacities are increased in a fair manner and the total reservation does not overwhelm the underlying network. Depending on the network's status and allocation policy, a virtual link may increase or decrease its capacity, for example, for a monetary incentive. VPN users send control packets whenever they want to resize their capacities, and the network handles them in an efficient and fair way. The simulation and analytic results in this paper show that our scheme is simple and robust such that the users and the network communicate using simple control packets and the link capacities are allocated efficiently.

Fingerprinting is one of the digital watermarking techniques, and is becoming more important as a copyright protection technique. Fingerprinting must resist collusion attacks. As a security index, "c-secureness" has been proposed, but it has been known that there is indeed no c-secure code. In this paper, we introduce a new index to measure the resilience of fingerprinting for collusion attacks and obtain some upper bounds and a lower bound on the index.

Field emission display (FED) is evolving as a promising technique of flat panel displays in the future. In this paper, various carbon based nanostructures are acted as cathode materials for field emission devices. Dendrite-like diamond-like carbon emitters, carbon nanotubes, carbon nanotips are synthesized by microwave plasma chemical vapor deposition. Many factors affect the performance of field emitters, such as the shape, work function and aspect ratio of emission materials. Modified process of carbon based nano-materials for enhancing field emission efficiency are included intrinsic and extrinsic process. These reformations contain the p-type and n-type doping, carburization and new ultra well-aligned carbon nano-materials. It is found that carbon nano-materials grown on micropatterned diode show higher efficiency of FED. In addition, to achieve a low- turn-on field, the novel scheme involving a new fabrication process of gated structure metal-insulator-semiconductor (MIS) diode by IC technology is also presented.

This paper investigates the accepting powers of deterministic, Las Vegas, self-verifying nondeterministic, and nondeterministic one-way multi-counter automata with time-bounds. We show that (1) for each k1, there is a language accepted by a Las Vegas one-way k-counter automaton operating in real time, but not accepted by any deterministic one-way k-counter automaton operating in linear time, (2) there is a language accepted by a self-verifying nondeterministic one-way 2-counter automaton operating in real time, but not accepted by any Las Vegas one-way multi-counter automaton operating in polynomial time, (3) there is a language accepted by a self-verifying nondeterministic one-way 1-counter automaton operating in real time, but not accepted by any deterministic one-way multi-counter automaton operating in polynomial time, and (4) there is a language accepted by a nondeterministic one-way 1-counter automaton operating in real time, but not accepted by any self-verifying nondeterministic one-way multi-counter automaton operating in polynomial time.

The certified discrete logarithm problem modulo p prime is a discrete logarithm problem under the conditions that the complete factorization of p-1 is given and by which the base g is certified to be a primitive root mod p. For the cryptosystems based on the intractability of certified discrete logarithm problem, Sakurai-Shizuya showed that breaking the Diffie-Hellman key exchange scheme reduces to breaking the Shamir 3-pass key transmission scheme with respect to the expected polynomial-time Turing reducibility. In this paper, we show that we can remove randomness from the reduction above, and replace the reducibility with the polynomial-time many-one. Since the converse reduction is known to hold with respect to the polynomial-time many-one reducibility, our result gives a stronger evidence for that the two schemes are completely equivalent as certified discrete log cryptosystems.

One of the difficulties in routing problem is in wirability which is to guarantee a physical connection of a given topological route. Wirability often fails since the width of a wire is relatively large compared with the size of modules. As a possible solution, this paper proposes an incremental wiring algorithm which generates wires net-by-net without overlapping other pre-placed circuit elements. The idea is to divide a wire into a series of rectangles and handles them as modules with additional constraints to keep the shape of the wire. The algorithm was implemented and experimented on a small instance to show its promising performance.

Obtaining a linearizing feedback and a coordinate transformation map is very difficult, even though the system is feedback linearizable. It is known that finding a desired transformation map and feedback is equivalent to finding an integrating factor for an annihilating one-form for single input nonlinear systems. It is also known that such an integrating factor can be approximated using the simple C.I.R method and tensor product splines. In this paper, it is shown that m integrating factors can always be approximated whenever a nonlinear system with m inputs is feedback linearizable. Next, m zero-forms can be constructed by utilizing these m integrating factors and the same methodology in the single input case. Hence, the coordinate transformation map is obtained.

In this paper, the problem of output feedback passification for nonlinear systems is considered. Contrary to the conventional methodologies, our approach does not require the normal form representation of the system. Consequent advantages include that the system need not have a well-defined relative degree. In particular, we present a necessary and sufficient condition for output feedback passification without relying on the normal form. The proposed condition finally leads to an extension for a recent result when the system does have a normal form.

A reconfigurable network interface called RHiNET-2/NI0 is developed for parallel processing of PCs distributed within one or more floors of a building. Two configurations: the HS (High Speed) configuration with only a high-speed primitive and the DSM (Distributed Shared Memory) configuration which supports sophisticated primitives can be selected by the network requirement. From the empirical evaluation, it appears that the HS configuration markedly improves the latency of data transfer compared with traditional network interfaces. On the other hand, the DSM configuration executes sophisticated primitives for distributed shared memory more than twice as fast as that of software implementation.

In many distributed systems, tokens are fundamental tools to manage resources shared by processes. Thus, monitoring tokens has become a significant problem in developing the distributed programs. This paper formulates the problems of monitoring tokens in terms of detecting the special global predicates, called summative global predicates. In this paper, several algorithms to detect various summative global predicates are developed and their time complexities are discussed.

A new device structure for electrooptic tunable wavelength filter is reported. Finger electrode electrooptic mode converters are placed on an optical waveguide. The drive voltage amplitude is changed along the propagation distance with a sinusoidal function. Changing the spatial period of sinusoidal voltage results in wavelength tuning. Structure uses interleaved mode converter groups generating cosine and sine function mode conversion strengths.

Burst switched WDM optical networks are coming up as suitable network architectures for future Optical Internet backbones. However, the lack of optical processing capabilities results in increased burst blocking probability, which in turn lead to very limited network performance. Efficient contention resolution algorithm is therefore necessary. In this paper, we propose a distributed wavelength assignment algorithm named Priority-based Wavelength Assignment (PWA) for such networks. Each node selectively assigns wavelengths based on the wavelength priority information "learned" from its wavelength utilization history in a distributed manner. As the learning process progresses, nodes in the same part of the network tend to assign different wavelengths to avoid contentions. Simulation results show that the PWA can effectively reduce the blocking probability and increase the performance of burst optical networks compared to previous algorithms such as random assignment.

It is found that the supercontinuum spectrum is generated from cross-phase modulated soliton pulses which are propagated through a dispersion-flattened/decreasing fiber with low birefringence. The cross-phase modulation is achieved by exciting two orthogonally polarized modes in a birefringent fiber and the effect of input azimuth of linearly polarized pulses is discussed theoretically and numerically.

We will present a novel core mode blocker fabricated with hydrogen loaded Ge-B co-doped fiber exposed to the electric arc discharge using local heat exposure. Tunable bandpass filter based on cascaded LPFGs with a core mode blocker inserted between the LPFGs will be also described. The characteristics are: 6.5-nm bandwidth, 30-nm tuning range, and 15-dB dynamic range, respectively. It can be very useful for application to wavelength stabilization and physical sensors.

Decreased power dissipation and transient voltage drops in CMOS power distribution networks are important for high-speed deep submicrometer CMOS integrated circuits. In this paper, three CMOS buffers based on the charge-transfer, split-path and bootstrapped techniques to reduce the power dissipation and transient voltage drop in power supply are proposed. First, the inverted-delay-unit is used in the low-power inverted-delay-unit (LPID) CMOS buffer to eliminate the short-circuit current of the output stage. Second, the low-swing bootstrapped feedback-controlled split-path (LBFS) CMOS buffer is proposed to eliminate the short-circuit current of the output stage by using the feedback-controlled split-path method. The dynamic power dissipation of the LBFS CMOS buffer can be reduced by limiting the gate voltage swing of the output stage. Moreover, the propagation delay of the LBFS CMOS buffer is also reduced by non-full-swing gate voltage of the output stage. Third, the charge-recovery scheme is used in the charge-transfer feedback-controlled 4-split-path (CRFS) CMOS buffer to recovery and pull up the gate voltage of the output stage for reducing power-delay product and power line noise. Based on HSPICE simulation results, the power-delay product and the transient voltage drop in power supply of the proposed three CMOS buffers can be reduced by 20% to 40% as compared to conventional CMOS tapered buffer under various capacitive load.

Polarimetric SAR interferometry has been successful and attractive for forest parameters (tree height and canopy extinction) estimation. In this paper, we propose to use the ESPRIT algorithm to extract the interferometric phase of local scatterers with polarimetric and interferometric SAR data. Two or three local scattering waves can be extracted at each image patch when a fully polarimetric data set (HH, HV, VV) is available. Furthermore, the ESPRIT can estimate two dominant local scattering centers when only a dual polarimetric data set (e.g., VV and VH) is provided. In order to demonstrate effectiveness the proposed technqiue, we examined the relation between local scattering centers extracted by this method and complex coherence of the coherent scattering model for vegetation cover. The results show that the three-wave estimation can be more accurate than the two-wave case. The extracted interferometric phases with full and dual polarization data sets correspond to effective ground and canopy scattering centers. In this investigation, SIR-C/X-SAR data of the Tien Shan flight-pass are used.

Optical Burst Switching (OBS) is one of the most important switching technologies in future optical Internet. One of critical design issues in OBS is how to reduce burst dropping resulting from resource contention. Especially when traffic load is high, there should be frequent deflection routing as well as more contentions in an optical burst-switched network. The burst loss performance can be improved by implementing a proper deflection routing scheme. In this paper, we propose a limited deflection routing scheme to prevent injudicious deflection routing. The proposed scheme reduces unnecessary contentions resulting from deflection routing itself, increasing the utilization of network resource such as channels. Simulation tests were performed to evaluate the performance of the proposed scheme.

A new algorithm for efficient arithmetic in an optimal extension field is proposed. The new algorithm improves the speeds of multiplication, squaring, and inversion by performing two subfield multiplications simultaneously within a single integer multiplication instruction of a CPU. Our algorithm is used to improve throughputs of elliptic curve operations.

Bidirected graphs which are generalizations of undirected graphs, have three types of edges: (+,+)-edges, (-,-)-edges and (+,-)-edges. Undirected graphs are regarded as bidirected graphs whose edges are all of type (+,+). The notion of perfection of undirected graphs can be naturally extended to bidirected graphs in terms of polytopes. The fact that a bidirected graph is perfect if and only if the undirected graph obtained by replacing all edges to (+,+) is perfect was independently proved by several researchers. This paper gives a polyhedral proof of the fact and introduces some new knowledge on perfect bidirected graphs.