In this paper, negative bias temperature instability (NBTI) reliability of pFETs is analyzed under the post-fabrication SRAM self-improvement scheme that we have developed recently, where cell stability is self-improved by simply applying high stress voltage to supply voltage terminal (VDD) of SRAM cells. It is newly found that there is no significant difference in both threshold voltage and drain current degradation by NBTI stress between fresh PFETs and PFETs after self-improvement scheme application, indicating that the self-improvement scheme has no critical reliability problem.

We propose a neighbor pattern coding (NPC) scheme with the aim of exploiting the structural feature fully to improve the performance of finger vein verification. First, one-pixel-wide edge is obtained to represent the direction of the binary vein pattern. Second, based on 8-neighbor pattern analysis, we design a feature-coding strategy to characterize the vein edge. Finally, the edge code flooding operation is defined to characterize all of other vein pixels according to the nearest neighbor principle. Experimental results demonstrate the effectiveness of the proposed method.

In this paper, a high performance current latch sense amplifier (CLSA) with vertical MOSFET is proposed, and its performances are investigated. The proposed CLSA with the vertical MOSFET realizes a 11% faster sensing time with about 3% smaller current consumption relative to the conventional CLSA with the planar MOSFET. Moreover, the proposed CLSA with the vertical MOSFET achieves an 1.11 dB increased voltage gain G(f) relative to the conventional CLSA with the planar MOSFET. Furthermore, the proposed CLSA realizes up to about 1.7% larger yield than the conventional CLSA, and its circuit area is 42% smaller than the conventional CLSA.

We investigated the effects of chemical treatments for removing native oxide layers on InAlN surfaces by X-ray photoelectron spectroscopy (XPS). The untreated surface of the air exposed InAlN layer was covered with the native oxide layer mainly composed of hydroxides. Hydrochloric acid treatment and ammonium hydroxide treatment were not efficient for removing the native oxide layer even after immersion for 15 min, while hydrofluoric acid (HF) treatment led to a removal in a short treatment time of 1 min. After the HF treatment, the surface was prevented from reoxidation in air for 1 h. We also found that the 5-min buffered HF treatment had almost the same effect as the 1-min HF treatment. Finally, an attempt was made to apply the HF-based treatment to the metal-InAlN contact to confirm the XPS results.

We investigated solid-phase growth reactions for the fabrication of β-FeSi2 films from Fe and FeSi sources by reflection high-energy electron diffraction (RHEED). To enhance the interdiffusion of Fe and Si for the growth of β-FeSi2, the use of FeSi instead of pure Fe as the source for the initial deposition was examined. The RHEED observation during the solid phase reaction indicated that the growth temperature was markedly decreased to 390 K using the FeSi source. We discuss the reaction mechanism of the solid phase growth of β-FeSi2 from Fe and FeSi sources in this paper.

Solid-state disks (SSDs) have received much attention as replacements for hard disk drives (HDDs). One of their noticeable advantages is their high-speed read/write operation. To achieve good performance, SSDs have an internal memory hierarchy which includes several volatile memories, such as DRAMs and SRAMs. Furthermore, many SSDs adopt aggressive memory management schemes under the assumption of stable power supply. Unfortunately, the data stored in the volatile memories are lost when the power supplied to SSDs is abruptly shut off. Such power failure is often observed in portable devices. For this reason, it is critical to provide a power failure protection scheme for reliable SSDs. In this work, we propose a power-failure protection scheme for SSDs to increase their reliability. The contribution of our work is three-fold. First, we design a power failure protection circuit which incorporates super-capacitors as well as rechargeable batteries. Second, we provide a method to determine the capacity of backup power sources. Third, we propose a data backup procedure when the power failure occurs. We implemented our method on a real board and applied it to a notebook PC with a contemporary SSD. The board measurement and simulation results prove that our method is robust in cases of sudden power failure.

First, this paper derives the prefix sum-of-products expression (PreSOP) and the number of products in a PreSOP for an interval function. Second, it derives Ψ(n,τp), the number of n-variable interval functions that can be represented with τp products. Finally, it shows that more than 99.9% of the n-variable interval functions can be represented with ⌈ n - 1 ⌉ products, when n is sufficiently large. These results are useful for a fast PreSOP generator and for estimating the size of ternary content addressable memories (TCAMs) for packet classification.

With the rapid expansion of vector data model application to digital content such as drawings and digital maps, the security and retrieval for vector data models have become an issue. In this paper, we present a vector data-hashing algorithm for the authentication, copy protection, and indexing of vector data models that are composed of a number of layers in CAD family formats. The proposed hashing algorithm groups polylines in a vector data model and generates group coefficients by the curvatures of the first and second type of polylines. Subsequently, we calculate the feature coefficients by projecting the group coefficients onto a random pattern, and finally generate the binary hash from binarization of the feature coefficients. Based on experimental results using a number of drawings and digital maps, we verified the robustness of the proposed hashing algorithm against various attacks and the uniqueness and security of the random key.

In order to implement complementary logic function with L-shaped tunneling field-effect transistors (TFETs), current drivability and subthreshold swing (SS) need to be improved more. For this purpose, high-k material such as hafnium dioxide (HfO2) has been used as gate dielectric rather than silicon dioxide (SiO2). The effects of device parameters on performance have been investigated and the design of L-shaped TFETs has been optimized. Finally, the performance of L-shaped TFET inverters have been compared with that of conventional TFET ones.

This paper studies stabilization of uncertain systems over finite data rate and lossy channels. Limitations on data rate and packet loss probability are derived, characterized by the product of the eigenvalues of the plant. It is worth noting that even if we assume the most conservative plant dynamics, existing limitations for nominal plants are looser than those given in this paper. This fact implies that plant uncertainties cause strictly higher requirements in communication. We consider linear discrete-time systems with parametric uncertainties and employ uniform quantizers, which have the simplest quantization structure. Under the setup, a necessary condition and a sufficient condition for stability are derived. In particular, for scalar plants case, the conditions are exact. They coincide with the existing results for nominal plants as a special case and hence generalize them to the uncertain case.

Temporal Self-Similarity Matrix (SSM) based action recognition is one of the important approaches of single-person oriented action analysis in computer vision. In this study, we propose a new kind of SSM and a fast computation method. The computation method does not require time-consuming pre-processing to find bounding boxes of the human body, instead it processes difference images to obtain action patterns which can be done very quickly. The proposed SSM is experimentally confirmed to have high power/capacity to achieve a better classification performance than four typical kinds of SSMs.

We have fabricated Pt/Si-rich oxide (SiOx)/TiN stacked MIM diodes and studied an impact of the structural asymmetry on their resistive switching characteristics. XPS analyses show that a TiON interfacial layer was formed during the SiOx deposition on TiN by RF-sputtering in an Ar + O2 gas mixture. After the fabrication of Pt top electrodes on the SiOx layer, and followed by an electro-forming process, distinct bi-polar type resistive switching was confirmed. For the resistive switching from high to low resistance states so called SET process, there is no need to set the current compliance. Considering higher dielectric constant of TiON than SiOx, the interfacial TiON layer can contribute to regulate the current flow through the diode. The clockwise resistive switching, in which the reduction and oxidation (Red-Ox) reactions can occur near the TiN bottom electrode, shows lower RESET voltages and better switching endurance than the counter-clockwise switching where the Red-Ox reaction can take place near the top Pt electrode. The result implies a good repeatable nature of Red-Ox reactions at the interface between SiOx and TiON/TiN in consideration of relatively high diffusibility of oxygen atoms through Pt.

This Letter presents a new feature named structured local binary Kirsch pattern (SLBKP) for image retrieval. Each input color image is decomposed into Y, Cb and Cr components. For each component image, eight 33 Kirsch direction templates are first performed pixel by pixel, and thus each pixel is characterized by an 8-dimenional edge-strength vector. Then a binary operation is performed on each edge-strength vector to obtain its integer-valued SLBKP. Finally, three SLBKP histograms are concatenated together as the final feature of each input colour image. Experimental results show that, compared with the existing structured local binary Haar pattern (SLBHP)-based feature, the proposed feature can greatly improve retrieval performance.

Oriental ink painting, called Sumi-e, is one of the most distinctive painting styles and has attracted artists around the world. Major challenges in Sumi-e simulation are to abstract complex scene information and reproduce smooth and natural brush strokes. To automatically generate such strokes, we propose to model the brush as a reinforcement learning agent, and let the agent learn the desired brush-trajectories by maximizing the sum of rewards in the policy search framework. To achieve better performance, we provide elaborate design of actions, states, and rewards specifically tailored for a Sumi-e agent. The effectiveness of our proposed approach is demonstrated through experiments on Sumi-e simulation.

Ultra-wideband (UWB) pulse radar has high range resolution and permeability in a dielectric medium, and has great potential for the non-destructive inspection or early-stage detection of breast cancer. As an accurate and high-resolution imaging method for targets embedded in a dielectric medium, extended range points migration (RPM) has been developed. Although this method offers an accurate internal target image in a homogeneous media, it assumes the permittivity of the dielectric medium is given, which is not practical for general applications. Although there are various permittivity estimation methods, they have essential problems that are not suitable for clear, dielectric boundaries like walls, or is not applicable to an unknown and arbitrary shape of dielectric medium. To overcome the above drawbacks, we newly propose a permittivity estimation method suitable for various shapes of dielectric media with a clear boundary, where the dielectric boundary points and their normal vectors are accurately determined by the original RPM method. In addition, our method iteratively compensates for the scattered waveform deformation using a finite-difference time domain (FDTD) method to enhance the accuracy of the permittivity estimation. Results from a numerical simulation demonstrate that our method achieves accurate permittivity estimation even for a dielectric medium of wavelength size.

We have fabricated highly-dense Si nano-columnar structures accompanied with Si nanocrystals on W-coated quartz, and characterized their local electrical transport in the thickness direction using atomic force microscopy (AFM) with a conductive cantilever. By applying DC negative bias to the bottom W electrode with respect to a grounded top electrode made of 10-nm-thick Au on the sample surface, current images reflecting highly-localized conduction were obtained in both contact and non-contact modes. This result is attributable to electron emission due to quasi-ballistic transport through Si nanocrystals via nanocolumnar structure.

Acoustic energy harvesters that function in environments where sound pressure is extremely high (150 dB), such as in engine rooms of aircraft, are expected to be capable of powering wireless health monitoring systems. This paper presents the power generation performance of a lead-zirconate-titanate (PZT) acoustic energy harvester with a vibrating PZT diaphragm. The diaphragm had a diameter of 2 mm, consisting of Al (0.1 µm)/PZT (1 µm)/Pt (0.1 µm)/Ti (0.1 µm)/SiO2 (1.5 µm). The harvester generated a power of 510-14 W under a sound pressure level of 110 dB at the first resonance frequency of 6.28 kHz. It was found that the generated power was increased to 2.010-13 W using a sound-collecting Helmholtz resonator cone with a height of 60 mm. The cone provided a Helmholtz resonance at 5.8 kHz, and the generated power increased from 9.710-15 W to 7.310-13 W at this frequency. The cone was also effective in increasing the bandwidth of the energy harvester.

The Internet is composed of many distinct networks, operated by independent Internet Service Providers (ISPs). The traffic and economic relationships of ISPs are mainly decided by their routing policies. However, in today's Internet, overlay routing, which changes traffic routing at the application layer, is rapidly increasing and this challenges the validity of ISPs' existing agreements. We study here the economic implications of overlay routing for ISPs, using an ISP interconnection business model based on a simple network. We then study the overlay traffic patterns in the network under various conditions. Combining the business model and traffic patterns, we study the ISPs' cost reductions with Bill-and-Keep peering and paid peering. We also discuss the ISPs' incentive to upgrade the network under each peering strategy.

In this paper, we suggest a novel pnp BJT structure to improve the matching characteristics of the bipolar junction transistor (BJT) which is fabricated using standard CMOS process. In the case of electrical characteristics, the collector current density Jc of the proposed structure (T2) is a little greater than the conventional structure (T1), which contributes to the greater current gain β of the proposed structure than the conventional structure. Although the matching characteristics of the collector current density of the proposed structure is almost similar to the conventional structure, that of the current gain of the proposed structure is better than the conventional structure about 14.81% due to the better matching characteristics of the base current density of the proposed structure about 59.34%. Therefore, the proposed BJT structure is desirable for high performance analog/digital mixed signal application.

We propose a retrieval method using scale invariant visual phrases (SIVPs). Our method encodes spatial information into the SIVPs which capture translation, rotation and scale invariance, and employs the SIVPs to determine the spatial correspondences between query image and database image. To compute the spatial correspondences efficiently, the SIVPs are introduced into the inverted index, and SIVP verification is investigated to refine the candidate images returned from inverted index. Experimental results demonstrate that our method improves the retrieval accuracy while increasing the retrieval efficiency.