Vertical Power MOSFETs are widely designed by deep well structures for breakdown requirement. In this study, we proposed, simulated, and analyzed a "shallow dual well" structure Power MOSFET, which utilize an n-well to cover the conventional p-well. The cell pitch can be reduced and results in an increased cell density. The reduced cell pitch and increased cell density improves the gate charge and on resistance performances about 66.5% and 15.8% without sacrificing the device breakdown owing to a shallow junction design. In addition, with the dual well structure design, the breakdown point will occur at the center of the well. Therefore, the capability of avalanche energy can be improved about 1.9 times than the tradition well structure.

Embedded memories have been used extensively in modern SoC designs. In order to estimate the power consumption of an entire design correctly, an accurate memory power models are needed. However, the memory power model that is commonly used in commercial EDA tools is too simple to estimate the power consumption accurately. In this work, we develop two methods to improve the accuracy of memory power estimation. Our enhanced memory power model can consider not only the operation mode of memory access, but also the address switching effects with scaling capability. The proposed approach is very useful to be combined with the memory compiler to generate accurate power model for any specified memory size without extra characterization costs. Then the proposed dummy modular approach can link our enhanced memory power model into the existing power estimation flow smoothly. The experimental results have shown that the average error of our memory power model is only less than 5%.

In order to reconstruct 3-D Euclidean shape by the Tomasi-Kanade factorization, one needs to specify an affine camera model such as orthographic, weak perspective, and paraperspective. We present a new method that does not require any such specific models. We show that a minimal requirement for an affine camera to mimic perspective projection leads to a unique camera model, called symmetric affine camera, which has two free functions. We determine their values from input images by linear computation and demonstrate by experiments that an appropriate camera model is automatically selected.

This paper proposes the most effective deployment scenario of the passive double-star (PON) system to provide multiple broadband services, such as high speed Internet access and broadcast services. The deployment costs of the two major PON technologies, wavelength division multiplexing (WDM) and 10 Gbps time division multiplexing (TDM), are analyzed using the latest cost trend and the most popular access network architecture. These two technologies are compared using the cost analysis results to identify the cost-effective scenarios of PON system deployment. Based on the comparison, this paper reveals that the WDM network becomes cost effective when the service penetration and the shift ratio becomes high.

In this paper, we propose a new preemptive scheme with release message in optical burst switching (OBS) networks. In the proposed scheme, when a low priority burst is preempted at some intermediate node, two RELEASE messages are sent immediately from the intermediate node to both source and destination nodes (two-way release message transmission), and the RELEASE messages release the corresponding wavelengths for the preempted burst. We consider six wavelength selection rules for the preemption and evaluate the performances of the selection rules by simulations. Numerical examples show that our scheme utilizes wavelengths effectively and, with the optimal selection rule, can decrease the burst loss probability in a large-scale DWDM network.

We investigate the issues involved in designing a packet scheduler for the proportional delay differentiation (PDD) model in differentiated services (DiffServ) networks. The PDD model controls the average waiting time of each class such that the average waiting time is proportional to its corresponding delay differentiation parameter. This paper proposes a novel packet scheduler for PDD referred to as the longest waiting time first (LWTF). By adding certain conditions, we found that the LWTF scheduler can be reduced to a known packet scheduler-priority queue with linear priorities (PQ-LP). The properties and behaviors of LWTF can be predicted from the analysis of PQ-LP. The simulation results in comparison with other PDD algorithms have also revealed that LWTF provides no worse level of service quality in long timescales and affords more accurate and robust control over the delay ratio in short timescales.

A novel PND (PMOS-NMOS-Depletion MOS) technology for a single poly gate non-volatile memory cell design has been reported for the first time. This technology features memory cell design with a differential cell architecture which enables to provide the higher performance for the key specifications such as programming time, erasing time, and endurance characteristics. This memory cell consists of 3-Transistors, PMOS, NMOS, and Depletion MOS transistors (hereafter PND). The DMOS in this cell is used for the tunneling device in the erasing operation, while the NMOS and the PMOS are used for the tunneling device and the coupling capacitor in the programming operation, respectively. The proposed PND design can allow lower applied voltage of the erase-gate (EG) and control-gate (CG) in the erasing and the programming operations so that the endurance characteristics can be improved because the DMOS suppresses the potential of floating-gate (FG) and hence the effective potential difference between the EG and the FG can be increased in the erasing operation. Based on the measured data, it can be expected that the erasing speed of the PND cell can be 125-fold faster than that of our previously reported work (PN type). Therefore, high performance and high reliability CMOS non-volatile memory without any additional process can be realized using this proposed PND technology.

To overcome the demerits of two passive optical networks; the small link capacity of the TDM-PON, and the ineffective link utilization of the WDM-PON; we propose a novel access network architecture featuring a WDM-based feeder network and a TDM-based distribution network. In this paper, we examine the design issues of the key constituent of SWE-PON (Scalable WDM-based Ethernet hybrid-PON) to validate its economic and practical feasibility. For flawless network operation, the wavelength tuning rule is investigated so that it does not collide between wavelengths from the tunable lasers belonging to the WDM coupler. Also, the potential problem between the tunable laser and the reflective operational device is analyzed in detail. From the numerical analysis and simulation, we demonstrate the variation of the network performance in terms of the upstream traffic delay and throughput of the ONU in accordance with the sharing structure of distribution network and the number of tunable laser devices (TLDs) at the feeder network.

This paper presents a method for lossy compression of digital video data by parametric line and Natural cubic spline approximation. The method estimates the variation of pixel values in the temporal dimension by taking group of pixels together as keyblocks and interpolating them in Euclidean space. Break and fit criterion is used to minimize the number of keyblocks required for encoding and decoding of approximated data. Each group of pixels at fixed spatial location is encoded/decoded independently. The proposed method can easily be incorporated in the existing video data compression techniques based on Discrete Cosine Transform or Wavelet Transform.

Utilizing the small bending radius of high index contrast optical waveguides, ultra-compact optical devices such as waveguide branch, Mach-Zehnder interferometer, arrayed waveguide grating filter, microring resonator filter, and so on can be realized. We have proposed and demonstrated a vertically coupled microring resonator as an Add/Drop filter, and recently realized a hitless wavelength channel selective switch (hitless tunable Add/Drop filter) using Thermo-Optic (TO) effect of double series coupled dielectric microring resonator. Using a high-index dielectric material as the core, the response time was reduced to 105 µs (rise time) and 15 µs (fall time), which are fifteen-fold and hundred-fold faster than that of polymer material, and the reproducibility by the heat cycle test was also improved to less than 0.01 nm. The tuning range of wavelength selective switch was expanded to 13.3 nm using the Vernier effect, and a large extinction ratio of more than 20 dB was realized. In this review, the principle and recent progress of microring resonator based wavelength selective switch will be introduced and some basic switching circuits required to optical cross connect will be discussed.

One approach to accommodating IP traffic on a wavelength division multiplexing (WDM) network is to construct a logical topology, establishing a set of lightpaths between nodes. The lightpaths carry IP traffic but do not require any electronic packet processing at intermediate nodes, thereby reducing the load on those nodes. When the IP and WDM networks have independent routing functions, however, the lightpaths in the WDM network may not be fully utilized by the IP router. It is therefore necessary to integrate the two routing mechanisms in order to utilize resources efficiently and adapt to changes in traffic. In this paper, we propose an integrated routing mechanism for IP over WDM networks. The key idea is to first prepare a set of virtual-links representing the lightpaths that can be established by the WDM network, then calculate the minimum cost route on an IP network including those links. Our simulation results show that when traffic patterns do not change, the throughput of our method is almost the same as that of a logical topology optimally designed for a given traffic demand. When traffic patterns change, the throughput of our method is about 50% higher than that of the logical topology.

A two-stage least square identification method is proposed for estimating ARMA (autoregressive moving average) coefficients from speech signals. A pulse-train like input sequence is often employed to account for the source effects in estimating vocal tract parameters of voiced speech. Due to glottal and radiation effects, the pulse train, however, does not represent the effective voice source. The authors have already proposed a simple but effective model of voice source for estimating AR (autoregressive) coefficients. This letter extends our approach to ARMA analysis to wider varieties of speech sounds including nasal vowels and consonants. Analysis results on both synthetic and natural nasal speech are presented to demonstrate the analysis ability of the method.

It is well known that a basic version (i.e., maximizing the number of base-pairs) of the RNA secondary structure prediction problem can be solved in O(n3) time by using simple dynamic programming procedures. For this problem, an O(n3(log log n)1/2/(log n)1/2) time exact algorithm and an O(n2.776+(1/ε)O(1)) time approximation algorithm which has guaranteed approximation ratio 1-ε for any positive constant ε are also known. Moreover, when two RNA sequences are given, there is an O(n6) time exact algorithm which can optimize structure and alignments. In this paper, we show an O(n5) time approximation algorithm for optimizing structure and alignments of two RNA sequences with assuming that the optimal number of base-pairs is more than O(n0.75). We also show that the problem to optimize structure and alignments for given N sequences is NP-hard and introduce a constant-factor approximation algorithm.

To keep in step with the rapid progress of high quality imaging systems, the Digital Cinema Initiative (DCI) has been issuing digital cinema standards that cover all processes from production to distribution and display. Various evaluation measurements are used in the assessment of image quality, and, of these, the required number of quantization bits is one of the most important factors in realizing the very high quality images needed for cinema. While DCI defined 12 bits for the bit depth by applying Barten's model to just the luminance signal, actual cinema applications use color signals, so we can say that this value has an insufficient theoretical basis. This paper, first of all, investigates the required number of quantization bits by computer simulations in discrete 3-D space for the color images defined using CIE's XYZ signal. Next, the required number of quantization bits is formulated by applying Taylor's development in the continuous value region. As a result, we show that 13.04 bits, 11.38 bits, and 10.16 bits are necessary for intensity, density, and gamma-corrected signal quantization, respectively, for digital cinema applications. As these results coincide with those from calculations in the discrete value region, the proposed analysis method enables a drastic reduction in the computer simulation time needed for obtaining the required number of quantization bits for color signals.

We have studied the electrical and breakdown characteristics of 5 nm-thick HfSiOxNy (Hf/(Hf + Si)=0.43, nitrogen content=4.5-17.8 at.%) in Al-gate and NiSi-gate capacitors. For Al-gate capacitors, the flat-band shift due to positive fixed charges increases with the nitrogen content in the dielectric layer. In contrast, for NiSi-gate capacitors, the flat band is almost independent of the nitrogen content, which is presumably controlled by the quality of the interface between NiSi and the dielectric layer. The leakage current markedly increases with nitrogen content. Correspondingly, although the time-to-soft breakdown, tSBD, gradually decreases with increasing nitrogen content, the charge-to-soft breakdown, QSBD, increases with the nitrogen content. For Al-gate capacitors, the Weibull slope of time-dependent dielectric breakdown (TDDB) under constant voltage stress (CVS) remains constant at 2 for a nitrogen content of up to 12.5 at.% and then decreases to unity at 17.8 at.%. This must be a condition critical to the formation of the percolation path for breakdown. In contrast, for NiSi gate capacitors, a Weibull slope smaller than unity was obtained, suggesting that structural inhomogeneity, involving defect generation, is introduced during the NiSi gate fabrication, but this negative impact is reduced with nitrogen incorporation.

The potential of optical circuit packaging technology is discussed. Special attention is paid to introduction of "optical wiring" at the printed wiring board level (i.e., in the "last 1 meter area") to overcome the bandwidth limitations of electrical copper-based wiring. The suitability of optical surface mount technology (O-SMT) as a possible solution is reviewed. It is shown that the key to the utility of O-SMT is high efficiency and alignment-free coupling between optical wiring and optical devices. O-SMT requires a method to change the beam direction from the horizontal to the vertical and vice versa in order to couple optical wiring in an OE-board and OE-devices mounted on the board. A novel method using an "optical pin" is proposed and investigated. Furthermore, an optical coupling method using a self-written waveguide called "optical solder" is reviewed. Several applications of self-written waveguides using a green laser and a photo-mask are demonstrated.

The quantization error of phase delay in an ultrasonic annular arrays imaging system is analyzed which impairs image resolution, and proper sampling rate is considered to reduce system complexity.

This paper investigates fast Packet Classification techniques, where a large routing table is divided into many much smaller tables by an index key at first; the resulting small tables are much easier to search. A traditional way is to use the front bits as the index key, but we show it's not an effective way to divide a routing table. In this paper, we propose three bit selection methods for division. They can be implemented by CAM or hash structure. Simulations show that the bit selection methods decrease the delay of classification 50% compared to the traditional method. We also propose an optimized method which is adapted to the biased traffic pattern, which shows 70% improvement in our simulation.

Twin-Channel (TC)-MOSFET with twin omega-gate (Ω-gate) Si channels and its fabrication process were proposed. The twin Si channels are able to be fabricated by self-aligned process utilizing wet etching of SiN and silicon-on-insulator (SOI) wafers. Three-dimensional (3-D) device simulation was performed to optimize gate structure for TC-MOSFET with 10 nm10 nm (TSiWG) channels with the gate length of 30 nm, and it was found that TC-MOSFET with right-angled Ω-gate in case the Lunder was 3 nm showed excellent device characteristics similar to the gate-all-around (GAA) devices corresponding to the gate structure as Lunder=5 nm. Fabrication process of twin Si channels was also investigated experimentally, and approximately 40 nm40 nm twin Si channels were successfully fabricated on SOI by the proposed fabrication process.

In numerical simulations of microwave structures using the alternating-direction implicit finite-difference time-domain (ADI-FDTD) method, the time marching scheme comprises two sub-iterations, where different updating schemes for evaluating E and H fields at each sub-iteration can be adopted. In this paper, the E-field implicit-updating (EFIU) and H-field implicit-updating (HFIU) schemes are compared with each other especially with regard to the implementation of local boundary conditions.