Ball Grid Array packages in which I/O pins are arranged in a grid array pattern realize a number of connections between chips and PCB, but it takes much time in manual routing. So the demand for automation of package routing is increasing. In this paper, we give the necessary and sufficient condition that all nets can be connected by monotonic routes when a net consists of a finger and a ball and fingers are on the two parallel boundaries of the Ball Grid Array package, and propose a monotonic routing method based on this condition. Moreover, we give a necessary condition and a sufficient condition when fingers are on the two orthogonal boundaries, and propose a monotonic routing method based on the necessary condition.

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.

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.

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.

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.

In real-time multimedia processing systems a very large part of the power consumption is due to the data storage and data transfer. Moreover, the area cost is often largely dominated by the memory modules. In deriving an optimized (for area and/or power) memory architecture, memory size computation is an important step in the exploration of the possible algorithmic specifications of multimedia applications. This paper presents a novel non-scalar approach for computing exactly the memory size in real-time multimedia algorithms. This methodology uses both algebraic techniques specific to the data-flow analysis used in modern compilers and, also, more recent advances in the theory of polyhedra. In contrast with all the previous works which are only estimation methods, this approach performs exact memory computations even for applications significantly large in terms of the code size, number of scalars, and number of array references.

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.

This letter presents an efficient Signed-Power-of-Two (SPT) term allocation for filter coefficients in order to improve the BER characteristics of digital communication systems. The performance of the present allocation is evaluated by BER characteristics through digital modulation simulations and FPGA-based digital implementation.

Radio frequency identification (RFID) technology is becoming increasingly attractive because of its high storage capacity and reprogrammability. There is a challenge to be overcome when a reader needs to read a number of tags within the reader's interrogation zone at the same time. In this paper, we present an anti-collision scheme in a RFID system. The scheme is based on the dynamic framed ALOHA protocol developed for radio networks. In our scheme, we propose two methods to estimate the number of tags. Simulation results indicate that the total number of time slots for reading all tags is about 4 times the number of tags that need to be read, including acknowledgement time slots. The main advantages of our scheme are the great performance of uplink throughput and its easy implementation for both readers and tags.

We propose a simple initial frame timing acquisition algorithm for cellular OFDMA systems. The proposed algorithm utilizes the 9 dB boost in preamble power set by the IEEE 802.16e standard. Simulation results show that the proposed algorithm succeeds in acquiring the starting point of a frame under not only single cell but also multi-cell environments, while the conventional autocorrelation-based method fails under multi-cell environment.

This paper proposes a new microstrip stepped-impedance resonator (SIR) used for bandpass filters with reduced size and improved stopband characteristics. A comprehensive treatment of both ends of the resonator with loaded triangular and rectangular microstrips is described. The design concept is demonstrated by two filter examples including four-resonator parallel-coupled Chebyshev bandpass and compact four-resonator cross-coupled elliptic-type filters. These filters are not only compact size due to the slow-wave effect, but also have a wider upper stopband resulting from the resonator bandstop characteristic. The filter designs are described in details. The simulated and experimental results are demonstrated and discussed.

This paper presents a family of rate-one quasi-orthogonal space-time block codes (QO-STBCs) for any number of transmit antennas. Full diversity of the proposed QO-STBCs is achieved via the use of constellation rotation. When the number of transmit antennas is even, these codes are delay "optimal." This property along with the quasi-orthogonality one allows the codes to have low decoding complexity. Besides, by applying lookup tables into the detection methods presented in [1] and generalizing them, two low-complexity maximum-likelihood (ML) decoders for the proposed QO-STBCs and for other existing QO-STBCs, called PMLD and QMLD, are obtained. Simulation results are provided to verify the bit error rate (BER) performances and complexities of both the proposed QO-STBCs and the proposed decoders.

This letter presents an efficient multichannel low-IF reception scheme that improves digital communication quality in the sense of BER performance. Created by simply adding cosine rolloff filters to the conventional multichannel receiver, the proposed receiver achieves much higher accuracy than the conventional one.

This paper proposes a compact interpolation scheme dedicated to a 1-dimensional position sensitive detector (PSD) with an optical sensing pixel array. The pixels are divided into even- and odd-numbered groups and winner take all (WTA) circuits are provided to each of the groups. The simulated results show that the detecting step-width is reduced to the half of the original one after applying the interpolation scheme.

Multiple-access interference (MAI) limits the bit error rate (BER) performance of CDMA uplink transmission. In this paper, we propose a generalized chip-interleaved CDMA with 2-dimensional (2D) spreading using orthogonal variable spreading factor (OVSF) codes to minimize the MAI effects and achieve the maximum available time- and frequency-domain diversity gains. We present the code assignment for 2D spreading to provide users with flexible multi-rate data transmission. A computer simulation shows that by the joint use of 2D OVSF spreading and chip-interleaving, MAI-free transmission is possible for the quasi-synchronous DS- or MC-CDMA uplink, and hence the single-user frequency-domain equalization based on the MMSE criterion can be applied for signal detection. The BER performance in a time- and frequency-selective fading multiuser channel is theoretically analyzed and evaluated by both numerical computation and computer simulation.

A one-dimensional (1-D) full search variable block size motion estimation (VBSME) architecture is presented in this paper. By properly choosing the partial sum of absolute differences (SAD) registers and scheduling the addition operations, the architecture can be implemented with simple control logic and regular workflow. Moreover, only one single-port SRAM is used to store the search area data. The design is realized in TSMC 0.18 µm 1P6M technology with a hardware cost of 67.6K gates. In typical working conditions (1.8 V, 25), a clock frequency of 266 MHz can be achieved.

We propose a Fault-Tolerant Object Group framework that provides group management and fault-tolerance services for consistency maintenance and state transparency as well. Through a virtual home-network simulation, we validate that the FTOG framework supports both of the reliability and the stability of the distributed home-network systems.

This paper presents the design, fabrication and characterization of a low actuation voltage capacitive shunt RF-MEMS switch for microwave and millimeter-wave applications based on a corrugated electrostatic actuated bridge suspended over a concave structure of coplanar waveguide (CPW), with sputtered nickel as the structural material for the bridge and gold for CPW line, fabricated on high-resistivity silicon (HRS) substrate using IC compatible processes for modular integration in a communication devices. The residual stress is very low because having both ends corrugated structure of the bridge in concave structure. The residual stress is calculated about 3-15 MPa in corrugated bridge and 30 MPa in flat bridge. The corrugated bridge of the concave structure requires lower actuation voltages 20-80 V than 50-100 V of the flat bridge of the planar structure in 0.3 to 1.0 µm thick Ni capacitive shunt RF-MEMS switch, in insertion loss 1.0 dB, return loss 12 dB, power loss 10 dB and isolation 28 dB from 0.5 up to 40 GHz. The residual stress of the bridge material and structure is critical to lower the actuation voltage.

This paper presents novel phase-continuous frequency hopping (FH) control for a direct frequency synthesizer (DFS) using a quadrature mixer driven by two direct digital synthesizers (DDSs). To achieve wideband FH in both of the lower and the upper sidebands of a local frequency in a quadrature mixer, the proposed DFS decreases or increases the phase of DDS output signals corresponding to frequency offset from a local frequency of the quadrature mixer. To realize phase decrement, the proposed method adds a complement number in a phase accumulator of a DDS, while a conventional DDS does not use phase decrement but uses a switchable combiner. In addition, as the phase accumulator output changes continuously by summing phase increment, the proposed method always assures phase continuity of a DFS output signal, which ends up suppressing sidelobe level of frequency hopped signals. The calculation and measurement results indicate that a sidelobe of a signal spectrum using the proposed phase continuous method is approximately 10 dB better than that using a conventional phase discontinuous method.

It has been shown that the maskless dye-diffusion technique is applicable to a conjugated polymer poly(9,9-dioctylfluorene). The introduction of Coumarin 6 and Nile red results in green and white emission, with the increased onset voltage for the both cases. It has also been confirmed that the heat treatment effect during the maskless dye diffusion technique results in not the increase but the decrease of the onset voltage, indicating that the dye plays a role of carrier trap in the polymer.