This paper presents an efficient technique for solving a Boolean matching problem in cell-library binding, where the number of cells in the library is large. As a basis of the Boolean matching, we use the notion NP-representative (NPR): two functions have the same NPR if one can be obtained from the other by a permutation and/or complementation(s) of the variables. By using a table look-up and a tree-based breadth-first search strategy, our method quickly computes the NPR for a given function. Boolean matching of the given function against the whole library is determined by checking the presence of its NPR in a hash table, which stores NPRs for all the library functions and their complements. The effectiveness of our method is demonstrated through experimental results, which show that it is more than two orders of magnitude faster than the Hinsberger-Kolla's algorithm.

A new receiver structure that combines the constant modulus algorithm (CMA) and the Kalman filter (KF) is investigated to exploit the advantages of both algorithms; simple implementation of blind algorithms, and excellent tracking ability, respectively. The proposed scheme achieves faster convergence and adaptability to the channel variation, which is verified through comparative simulations in doubly-selective (time- and frequency-selective) fading channels.

A new approach to low-complexity rate allocation scheme in closed loop MIMO-OFDM system is proposed. The new scheme utilizes ordered statistics of channel matrix's singular values to simplify the ideal scheme which uses water filling in both frequency and space domain. Unlike the conventional simplified algorithm called FFC [1] ("frequency flat constraint"), the proposed scheme has no restrictions of the numbers of antennas. The improvement of SNR gain with this new scheme is about 0.8 dB in 2-antenna systems with a little more complexity than FFC.

Technical terms are linguistic representations of a domain concept, and their constituents are components used to represent the concept. Technical terms are usually multi-word terms and their meanings can be inferred from their constituents. Therefore, term constituents are essential for understanding the designated meaning of technical terms. However, there are several problems in finding the correct meanings of technical terms with their term constituents. First, because a term constituent is usually a morphological unit rather than a conceptual unit in the case of Korean technical terms, we need to first identify conceptual units by chunking term constituents. Second, conceptual units are sometimes homonyms or synonyms. Moreover their meanings show domain dependency. It is therefore necessary to give information about conceptual units and their possible meanings, including homonyms, synonyms, and domain dependency, so that natural language applications can properly handle technical terms. In this paper, we propose a term constituent alignment algorithm that extracts such information from bilingual technical term pairs. Our algorithm recognizes conceptual units and their meanings by finding English term constituents and their corresponding Korean term constituents for given English-Korean term pairs. Our experimental results indicate that this method can effectively find conceptual units and their meanings with about 6% alignment error rate (AER) on manually analyzed experimental data and about 14% AER on automatically analyzed experimental data.

A nonlinear optical fiber loop mirror (NOLM) adapted for all-optical 2R operation at ultrahigh bit-rates was experimentally and theoretically investigated. The proposed NOLM was created by adding inline/external fiber polarizers and also an inline optical phase-bias compensator (OPBC) to a standard NOLM. A theoretical investigation revealed that the operation of the standard NOLM became unstable due to residual polarization crosstalk of the polarization-maintaining optical components making up the NOLM, and that it could be dramatically improved with the inline/external polarizers. The NOLM with the polarizers ensured stable switching operation with high switching-dynamic-range (>30 dB) against the change of the wavelength of the input clock pulses, and the change of the environment temperature. We also experimentally verified that the OPBC played a dramatic role to ensure excellent dynamic switching performance of the NOLM, and to achieve signal-Q-recovery of the regenerated signals. All optical 2R experiments at 40 Gb/s and 160 Gb/s were performed with the modified NOLM. Signal regeneration with improved extinction ratio and signal Q value was successfully demonstrated. Q-recovery to the input of the control pulses degraded with ASE noise accumulation was also successfully achieved.

This paper presents novel multi-band equilateral triangular microstrip antennas (ET-MSAs) fed by an L-shaped feeding probe. Two types of the ET-MSA are proposed in this paper; they are ET-MSA with closed folded slots and open folded slots with an embedded bridge. The antenna prototypes presented in this paper assume four folded slots in which a metal strip is inserted to realize a good multi-band performance. In addition, the open folded slots, in which the metal strip inside the folded slot is connected to the ET-MSA by the embedded metal bridge, leads to miniaturize the antenna. The proposed antennas are printed on the top layer of a PTFE substrate while the L-probe is printed on the bottom one. The L-shaped probe is utilized due to its tremendous performance in providing a wideband impedance matching. Five resonant frequencies of the ET-MSAs with closed folded slots and with open folded slots are predicted by the electromagnetic simulator (IE3D) based on the method of moment, respectively. Some parametric studies have been also investigated to meet an appropriate multi-band performance. A broadside radiation pattern and gain of 3.0-7.0 dBi have been confirmed by the measurement for the entire observed frequencies. Measured results agree well with the prediction. Thus, these antenna systems are demonstrated to be useful models for a multi-band planar antenna.

A unified representation for various kinds of speculations and global scheduling algorithms is presented. After introducing several types of local and global speculations, reviewing our conventional method called conditional vector-based list scheduling, and discussing some of its limitations, we introduce the unique notion of generalized condition vectors (GCVs), which can represent most varieties of speculations and multiple branches as a single vector. The unification of parallel branches and partially unresolved nested conditional branches is discussed. Then, a scheduling algorithm using GCVs is proposed. Experimental results show the effectiveness of the GCV-based scheduling method.

Recently, a word-valued source has been proposed as a new class of information source models. A word-valued source is regarded as a source with a probability distribution over a word set. Although a word-valued source is a nonstationary source in general, it has been proved that an entropy rate of the source exists and the Asymptotic Equipartition Property (AEP) holds when the word set of the source is prefix-free. However, when the word set is not prefix-free (non-prefix-free), only an upper bound on the entropy density rate for an i.i.d. word-valued source has been derived so far. In this paper, we newly derive a lower bound on the entropy density rate for an i.i.d. word-valued source with a finite non-prefix-free word set. Then some numerical examples are given in order to investigate the behavior of the bounds.

Organic static induction transistors (OSITs) with vertical structure have advantage of lower operational voltage compared to the organic field effect transistors with conventional lateral structure. In this study, OSITs based on pentacene films were applied to fabricate the organic inverters which can operate at low voltage. The experimental results demonstrate that organic inverters based on the OSITs show basic transfer characteristics and a low operational voltage of 2 V.

We prepared transparent polymer films doped with π-conjugated organic dyes around a multimode silica fiber and observed very narrow fluorescence peaks as compared with the fluorescence in solution. The peak position showed no dependence on the excitation wavelength, indicating that it could not be explained by a whispering gallery mode in a medium with broad optical gain. The peaks can be explained by amplified spontaneous emissions (ASE) because the intensity depended linearly on the excitation intensity with a threshold. When the dye-doped film was formed on the portion of a fiber with the clad etched out and was excited by the polarized laser propagating inside the fiber core, we observed ASE peaks not of the dyes but of the optical fiber itself, suggesting the possibility that the dyes were oriented with their transition moment pointing parallel to the film surface. These fiber ASE peaks shifted to longer wavelength when we varied the excitation wavelength to shorter wavelength, which clearly ruled out the possibility of silicate Raman scattering as the origin.

A color filter is the penetrable device adhering red, green, and blue organic color resists onto the surface of glass substrate for application of liquid crystal displays. It is fabricated by several technologies, including lithographic processes of coating, baking, exposing, etching, and rinsing. Inkjet printing technology has potentially implemented on the fabrication of the large-size panel with organic molecular film since this technology offers an efficient and steady production procedure. To achieve the basic specifications and requirements of high color performance, high color purity, high flatten, low reflective, and low production cost, inkjet printing technology will be seriously considered in the color filter manufacturing. Here we present the experimental results on physical and chromatic characteristics of color filters by implementing inkjet printing technology. To verify the chromatic characteristics of the resultant color filters, CIE 1931 chromaticity diagram is adopted to present the coordination of color distribution. For the green color ink, the results are x=0.30950.04, y=0.59120.04, brightness of Y=58.887 for 50 droplets and x=0.31030.04, y=0.57840.04, brightness of Y=60.328 for 41 droplets. For the blue color ink, the result is x=0.14900.04, y=0.10150.04, brightness of Y=8.808. For the red color ink, the result is x=0.5720.04, y=0.3200.04, brightness of Y=27.1.

This paper proposes a simple yet sufficient Si-substrate modeling for interconnect resistance and inductance extraction. The proposed modeling expresses Si-substrate as four filaments in a filament-based extractor. Although the number of filaments is small, extracted loop inductances and resistances show accurate frequency dependence resulting from the proximity effect. We experimentally prove the accuracy using FEM (Finite Element Method) based simulations of electromagnetic fields. We also show a method to determine optimal size of the four filaments. The proposed model realizes substrate-aware extraction in SoC design flow.

This paper presents the characteristics and modeling of VoIP traffic for a real network. The new model, based on measured data, shows a significant difference from the previously proposed models in terms of parameters and their effects. It is found that the effects of background noise and ringing tones have essential influences on the model. The observed distributions of talkspurt and silent durations have long-tail characteristics and considerably differ from the existing models. An additional state called "Long burst", which represents the background noise at the talker's place, is added into the continuous-time Markov process model. The other three states, "Talk", "Short silence" and "Long silence", represent the normal behavior of the VoIP user. Models for conversational speech containing the communication during the dialogue are presented. In the case of the VoIP traffic aggregation, the simplified models, which neglect the conversation's interaction, are proposed. Depending on the occurrences of background noise during the speech, the model is classified as "noisy speech" or "noiseless speech". The measured data shows that the background noise typically increases the data rate by 60%. Simulation results of aggregated VoIP traffic indicate the self-similarity, which is analogous to the measured data. Results from the measurements support the fact that except the ringing duration the conversations from both the directions can be modeled in identical manner.

The rapidly increasing bandwidth requirements of IP traffic mean that networks based on optical technologies in conjunction with IP routing technologies will provide the backbone of the next generation Internet. One of the major issues is how to construct an optical-technology-based backbone network that offers the economical transport of large-scale IP/MPLS services while achieving reliable, robust network. The key to achieving this objective lies in multilayer coordination technologies using Multi-Layer Service Network [MLSN] Architecture, that we previously proposed [2]. One of the important aspects of MLSN architecture is ability to effectively use GMPLS network resources by IP/MPLS service networks. We propose extensions to previously proposed MLSN architecture. The proposed extensions to MLSN architecture are tailored to address "service virtualization and separation" of various service networks over GMPLS backbone. As a part of this extended MLSN architecture, we introduce novel concepts known as Logical Router (LR) and Virtual Router (VR) that would enable border router to be services domain router, so that it can connect multiple service networks such as L2VPN, L3VPN etc., over GMPLS backbone by offering service separation or virtualization. This service separation/isolation greatly enhances the reliability of next generation networks, as any failure on one service should be isolated from others. We evaluate our extended network architecture against requirements for the large scale network targeting at introducing such new technology to cope with vast traffic explosion and challenges in operation and service provision sophistication.

Despite the extensive literature on current conveyor-based voltage-mode first-order all-pass filters, no filter circuits have been reported to date that simultaneously achieve all of the advantageous features: (i) the employment of only one current conveyor, (ii) the employment of only one grounded capacitor, (iii) the employment of only one resistor, (iv) no need to impose component choice conditions, and (v) low active and passive sensitivities. In this letter, we describe such a filter structure with all of the above features simultaneously present, without trade-offs. H-Spice simulation results using the TSMC025 process and 1.25 V supply voltages validate the theoretical predictions.

In this study we have employed an effective technique for dosimetric analyses of base station antennas in an underground environment. The technique combines a ray-tracing method and the finite-difference time-domain (FDTD) method to calculate the specific absorption rate (SAR) in the human body. The ray-tracing method was applied to evaluate the incident fields in relation to the exposed subject in a three-dimensional space, while the FDTD method was used to calculate the detailed SAR distributions in the human body. A scenario under an underground passage with the installation of a top-loaded monopole antenna was analyzed to investigate the relationship between the actual antenna exposure and a plane-wave exposure. The results show that the plane-wave exposure overestimated the whole-body average SAR in most cases, although this was not always true for peak SAR. The finding implies not only the usefulness of the present uniform-exposure-based reference level for the whole-body average SAR evaluation but also the necessity of modeling actual underground environment for high-precision local peak SAR evaluation.

Software defined radio, which uses reconfigurable signal processing devices, requires the determination of multiple unknown parameters to realize the potential capabilities of adaptive communication. Evolutional algorithms are optimal multi dimensional search techniques, and are well known to be effective for parameter determination. This letter proposes an evolutional algorithm for learning the mobile time-varying channel parameters without any specific assumption of scattering distribution. The proposed method is very simple to realize, but can provide precise channel estimation results. Simulations of an OFDM system show that for an example of OFDM communication under the time-varying fading channel, the proposed learning method can achieve the better BER performance.

This paper describes a flexible strategy to generate candidate answers for factoid questions in Question Answering (QA) systems. Most QA systems have predefined the conceptual categories for candidate answers. But if the conceptual category of answers to any question is not prepared in the QA system, it is hard to extract correct answers to that question. Therefore, we propose an extraction method for IS-A relation patterns which describe relations between the nominal target concepts of question and candidate answers. The extracted IS-A relation patterns can be used for questions with an unexpected target concept.

We present a TSK (Takagi-Sugeno-Kang)-based Linguistic Fuzzy Model (TSK-LFM) with uncertain model output. Based on the Linguistic Model (LM) proposed by Pedrycz, we develop a comprehensive design framework. The main design process is composed of the automatic generation of the contexts, fuzzy rule extraction by Context-based Fuzzy C-Means (CFCM) clustering, connection of bias term, and combination of TSK and linguistic context. Finally, we contrast the performance of the presented models with other models for coagulant dosing process in a water purification plant.

Most digital signal processing (DSP) algorithms for multimedia and communication applications require multiplication and addition operations. Especially matrix-matrix or matrix-vector the multiplications frequently used in DSP implementations needs inner product arithmetic which takes the most processing time. Also multiplications for the DSP algorithms for software defined radio (SDR) applications require different input bitwidths. Therefore, the multiplications for inner product need to be sufficiently flexible in terms of bitwidths to utilize hardware resources efficiently. This paper proposes a novel reconfigurable inner product architecture based on a pipelined adder array, which offers increased flexibility in bitwidths of input arrays. The proposed architecture consists of sixteen 44 multipliers and a pipelined adder array and can compute the inner product of input arrays with any combination of multiples of 4 bitwidths such as 44, 48, 412, ... 1616. Experimental results show that the proposed architecture has latency of maximum 9 clock cycles and throughput of 1 clock cycle for inner product of various bitwidths of input arrays. When TSMC 0.18 µm libraries are used, the chip area and critical path of the proposed architecture are 186,411 gates and 2.79 ns, respectively. The proposed architecture can be applied to a reconfigurable arithmetic engine for real-time SDR system designs.