Embedded systems are used in broad fields. They are one of the indispensable and fundamental technologies in a highly informative society in recent years. As embedded systems are large-scale and complicated, it is prosperous to design and develop a system LSI (Large Scale Integration). The structure of the system LSI has been increasing complexity every year. The degree of improvement of its design productivity has not caught up with the degree of its complexity by conventional methods or techniques. Hence, an idea for the design of a system LSI which has the flow of describing specifications of a system in UML (Unified Modeling Language) and then designing the system in a system level language has already proposed. It is important to establish how to convert from UML to a system level language in specification description or design with the idea. This paper proposes, extracts and verifies transformation rules from UML to SpecC which is one of system level languages. SpecC code has been generated actually from elements in diagrams in UML based on the rules. As an example to verify the rules, "headlights control system of a car" is adopted. SpecC code has been generated actually from elements in diagrams in UML based on the rules. It has been confirmed that the example is executed correctly in simulations. By using the transformation rules proposed in this paper, specification and implementation of a system can be connected seamlessly. Hence, it can improve the design productivity of a system LSI and the productivity of embedded systems.

Based on the periodical-loaded principle, a new wider stop-band filter is presented. The design equations are provided, the validity of which is proved by the measured results. Compared with loaded stub of length 1/4λg, the improved T-shape stub can change admittance paralleled with microstrip line and widen the band width of the band-stop filter. The size of the filter loaded by one side can be reduced by 2/3. The stop-band filter loaded by one side and two sides are simulated and realized. The filter loaded by two sides can achieve very wide stop-band. In addition, the stop-band of the new type of filter is deep and steep.

The conditional sum adder (CSA) has been shown to outperform other adders applied in high-speed applications. This investigation proposes a modified CSA called the conditional carry adder (CCA). Based on the proposed adder architecture, six 64-bit hybrid dual-threshold CCAs for power-aware applications were discussed. Architectural modification of the CCA raises the operation speed, decreases the power dissipation, and lowers the hardware overhead. The proposed 64-bit CCA can decrease the number of multiplexers and internal nodes in the adder design by around 27% compared to the 64-bit CSA. Furthermore, components on critical paths use a low threshold voltage to accelerate the speed of operation, and other components use the normal threshold voltage to save power. This feature is very useful in implementing power-aware arithmetic systems. One of the proposed circuits has the lowest power-delay product and energy-delay product. The hybrid circuit represents a fine compromise between power and performance. Its power efficiency is better than that of the single threshold voltage circuit designs.

A 3-bit flash analog-to-digital converter (ADC) for electronic dispersion compensation (EDC) was developed using InP HBTs. Nyquist operation was confirmed up to 24 Gsps, which enables oversampling acquisition for 10 Gbit/s non-return-to-zero (NRZ) signals. The ADC can also be operated at up to 37 Gsps for low input frequencies. To reduce aperture jitter and achieve a wide band of over 7 GHz, an analog input signal for all pre-amplifiers and a clock signal for all latched comparators are provided as traveling waves through coplanar transmission lines. EDC was demonstrated by capturing a 10-Gbit/s pseudo-random bit stream (PRBS) with the waveform degraded by polarization-mode dispersion (PMD). By using the captured data, we confirmed that a calculation of a transversal filter mitigates PMD.

It is not always possible to find a global parse for an input sentence owing to problems such as errors of a sentence, incompleteness of lexicon and grammar. Partial parsing is an alternative approach to respond to these problems. Partial parsing techniques try to recover syntactic information efficiently and reliably by sacrificing completeness and depth of analysis. One of the difficulties in partial parsing is how the grammar might be automatically extracted. In this paper we present a method of automatically extracting partial parsing rules from a tree-annotated corpus using the decision tree method. Our goal is deterministic global parsing using partial parsing rules, in other words, to extract partial parsing rules with higher accuracy and broader expansion. First, we define a rule template that enables to learn a subtree for a given substring, so that the resultant rules can be more specific and stricter to apply. Second, rule candidates extracted from a training corpus are enriched with contextual and lexical information using the decision tree method and verified through cross-validation. Last, we underspecify non-deterministic rules by merging substructures with ambiguity in those rules. The learned grammar is similar to phrase structure grammar with contextual and lexical information, but allows building structures of depth one or more. Thanks to automatic learning, the partial parsing rules can be consistent and domain-independent. Partial parsing with this grammar processes an input sentence deterministically using longest-match heuristics, and recursively applies rules to an input sentence. The experiments showed that the partial parser using automatically extracted rules is not only accurate and efficient but also achieves reasonable coverage for Korean.

The three beam-switched top-loaded antenna is suited to be applied to a wireless local area network to switch the radiation pattern by arranging several unidirectional antennas. In this paper, a three beam switched top loaded monopole antenna is proposed to realize its small size and planar structure. Three top loaded monopole antennas are arranged around a parasitic hexagonal patch at intervals of 120 degrees. The feed element is selected by the switching device to switch the radiation pattern. This antenna allows for reduction in the number of elements as well as downsizing. The front to back ratio (F/B) becomes 23 dB by selecting suitable parameters.

The reflection characteristics of large alternating-phase fed single-layer waveguide arrays with center-feeds are investigated to identify the mechanism for bandwidth narrowing effects. Firstly, the overall reflection for the whole array is analyzed by FEM and fine agreement with measurements is demonstrated. It is deviating from the conventional prediction based upon a simple sum of reflections from components in the array, such as the multiple-way power divider, the slot waveguides and the aperture at the antenna input. Careful diagnosis reveals that the mutual coupling between the alternating phase waveguides via external half-space is the key factor in reflection accumulation. Amongst all, the slot with strong excitation whose position depends upon the aperture illumination design produces the dominant contribution in the mutual coupling.

This paper addresses the variation of the attenuation characteristics of the Specific Absorption Rate (SAR) in a lossy medium as a function of the distance between an antenna and the medium with different EM-source sizes. Analysis and measurements were performed using a dipole antenna at 900 MHz and a COST244 cubic phantom. From this, an empirical equation has been derived, representing the attenuation characteristics of the SAR. The equation takes into consideration an energy loss due to the spatial spread of electromagnetic waves. In the case where an antenna is placed more than λ/2π away from the medium, the attenuation characteristics of the SAR are those obtained from plane waves in the lossy medium. In the case where a half-wavelength dipole antenna is located close to the medium, at a distance of less than λ/2π, the attenuation characteristics of the SAR are calculated from an equation that includes a loss caused by the spread of energy as a cylindrical wave. Moreover, when the length of antenna is short, it is found that a spatial attenuation factor appropriate to a spherical wave should be taken into account.

The recognition limit of luminance difference in the human visual system (HVS) has not been studied systematically. In this paper, surround adapted Weber-Fechner fraction is calculated based on the crispening effect. It is found that surround adapted fractions have reduced to 1/3 of the traditional Weber-Fechner fractions. As compared with Breitmeyer's experiments, the presented result is a reasonable one. It can be used as some guide to design the digital display system when a designer needs to decide bit count of digital signal in considering of the limit of brightness level, and as the inspection tool of display manufacturing of brightness smear, defect, and so on.

We present a method of stabilizing a class of nonlinear systems which are not necessarily feedback linearizable. First, we show a new way of constructing a diffeomorphism to transform a class of nonlinear systems to the feedback linearized form with perturbation. Then, we propose a semi-globally stabilizing control law for nonlinear systems that are connected by a chain of integrator perturbed by arbitrary nonlinear terms. In our approach, we have flexibility in choosing a diffeomorphism where the system is not restricted to involutivity and this leads to reduction in computational burden and flexibility in controller design.

In VDSM era, crosstalk is becoming a more and more vital factor in high performance VLSI designs, making noise mitigation in early design stages necessary. In this paper, we propose an effective algorithm optimizing crosstalk under congestion constraint in the layer assignment stage. A new model for noise severity measurement is developed where wire length is used as a scale for the noise immunity, and both capacitive and inductive coupling between sensitive nets are considered. We also take shield insertion into account for further crosstalk mitigation. Experimental results show that our approach could efficiently reduce crosstalk noise without compromising congestion compared to the algorithm proposed in [1].

In QoS routing, load balancing routing algorithm for long-lived traffic can be used efficiently to minimize the number of routing update, control traffic overhead and computational overhead which mainly come from network traffic fluctuation. The congestion problem from short-lived traffic is however difficult to handle. A simple and robust algorithm is needed for short-lived traffic to reduce the traffic loss probability. In the paper, we proposed a new hybrid routing schemes for short-lived traffic and long-lived traffic. An alternate routing algorithm is applied for the short-lived traffic when congestion occurs. We restricted the number of additional hops in the path to minimize the negative effect of alternate routing algorithm. The proposed algorithm reduces packet loss probability from 0.6% to 1.7% under various link utilizations. We also compare our proposed algorithms with and without crank-back.

Recently, efficient algorithms have been proposed for finding all characteristic curves of one-port piecewise-linear resistive circuits. Using these algorithms, a middle scale one-port circuit can be represented by a piecewise-linear resistor that is neither voltage nor current controlled. In this letter, an efficient algorithm is proposed for finding all dc operating points of piecewise-linear circuits containing such neither voltage nor current controlled resistors.

We propose a rapid and reliable signal acquisition scheme for UWB (Ultra Wide Band) systems in indoor wireless environments. The proposed scheme is a two-step search with different thresholds and search windows, where each step utilizes the single-dwell search with the bit reversal. Simulation results show that the proposed scheme for the UWB signals can achieve significant reduction of the required mean acquisition time as compared to other schemes including general double-dwell search scheme for various threshold levels. Furthermore, it is also observed that the proposed scheme can achieve much faster and reliable signal acquisition as the first threshold is larger in noisy environments.

Numerical Stability of the Finite Element/Finite Difference Time Domain Hybrid algorithm is dependent on the hybridization mechanism adopted. A framework is developed to analyze the numerical stability of the hybrid time marching algorithm. First, the global iteration matrix representing the hybrid algorithm following different hybridization schemes is constructed. An analysis of the eigenvalues of this iteration matrix reveals the stability performance of the algorithm. Thus conclusions on the performance with respect to numerical stability of the different schemes can be arrived at. Further, numerical experiments are carried out to verify the conclusions based on the stability analysis.

In order to achieve omni-directional coverages on base station antennas for fixed wireless access systems (FWA), a TM01 mode conical horn with 4.6λ aperture size was employed as a feed horn for an axisymmetrical reflector antenna. Here, a shaped dielectric lens was inserted in the conical horn so as to achieve low sidelobe radiation characteristics. However, it was pointed out that radiation pattern shaping ability was degraded in this small lens antenna. In this paper, deteriorations of aperture distributions in a shaped lens are clarified through FDTD calculations. Severe phase delays are shown in the aperture phase distributions. A novel lens shaping method of compensating the phase delays is developed. Aperture distributions and radiation patterns of the corrected lens are estimated through FDTD calculations. Satisfactory uniform phase distributions in aperture distributions and low sidelobe radiation patterns are ensured.

A folded loop antenna for handsets has already been introduced and shown as one of balance-fed antennas for handsets, which is very effective to mitigate the antenna performance degradation due to the body effect. In order to meet the requirements for the latest handsets such as low profile and small size, a folded loop antenna is modified. The antenna, which is possibly built in the handsets, is newly proposed. Low profile and small size is achieved by consisting of the half of low profile folded loop antenna, which has a structure folded loop elements sideways so that the antenna can be placed on the ground plane (GP). In the analysis, the electromagnetic simulator based on the FDTD (Finite Difference Time Domain) method is used and the design parameters useful in practical operation are found. The electromagnetic simulator based on the Method of Moment (MoM) is used to calculate the current distribution on the antenna element and the GP. An example of low profile and small size antenna which has wideband characteristics are designed based on these parameters, and the antenna characteristics such as VSWR, the current distributions and the radiation patterns are compared with Planar Inverted-F Antenna (PIFA), which is one of conventional built-in antennas for handset. As a result, it has been confirmed that the physical volume of the antenna, which has been introduced here, becomes smaller than that of PIFA. In addition, the radiation efficiency of these antennas is measured and the results are compared with each other.

This paper presents new encoding methods for the binary genetic algorithm (BGA) and new converting methods for the real-coded genetic algorithm (RCGA). These methods are developed for the specific case in which some parameters have to be searched in wide ranges since their actual values are not known. The oversampling effect which occurs at large values in the wide range search are reduced by adjustment of resolutions in mantissa and exponent of real numbers mapped by BGA. Owing to an intrinsic similarity in chromosomal operations, the proposed encoding methods are also applied to RCGA with remapping (converting as named above) from real numbers generated in RCGA. A simple probabilistic analysis and benchmark with two ill-scaled test functions are carried out. System identification of a simple electrical circuit is also undertaken to testify effectiveness of the proposed methods to real world problems. All the optimization results show that the proposed encoding/converting methods are more suitable for problems with ill-scaled parameters or wide parameter ranges for searching.

We present a simple bit allocation scheme based on adaptive coding for MIMO-OFDM (Multiple Input Multiple Output - Orthogonal Frequency Division Multiplexing) systems with V-BLAST (Vertical-Bell laboratories LAyered Space-Time) detector. The proposed scheme controls the code rate of the channel coding and assigns the same modulation and coding to the set of selected sub-channels, which greatly reduces the feedback burden while achieving good performance. Simulation results show that the proposed scheme with minimal feedback provides significant performance improvement over other systems.

A lasing charactrization of a Brillouin/erbium optical fiber laser (BEFL) is experimentally discussed. In the BEFL, an erbium-doped fiber amplifier (EDFA) is incorporated into the Brillouin laser resonator to enhance small Brillouin gain, which makes the configuration of the Brillouin laser resonator easy and flexible. The experimental results show that the output power of the BEFL has a threshold against the Brillouin pump power, and above the Brillouin threshold, the output power increases linearly with the EDFA pump power. The BEFL threshold decreases with increasing the length of the optical fiber in the laser resonator used as a Brillouin gain medium. The BEFL oscillates in a stable single longitudinal mode because the bandwidth of the Brillouin gain profile is very narrow ( 30 MHz). The relative intensity noise (RIN) and the spectral lineshape were measured. The noise floor level decreases with increasing the EDFA pump power, and the full-width at half maximum of the BEFL was measured to be about 8 kHz.