Hiroyuki MANABE Munekazu DATE Hideaki TAKADA Hiroshi INAMURA
Liquid crystal displays (LCDs) are suitable as elements underlying wearable and ubiquitous computing thanks to their low power consumption. A technique that uses less power to drive 1-pixel LCDs is proposed. It harvests the charges on the LCD and stores them in an external capacitor for reuse when the polarity changes. A simulation shows that the charge reduction depends on the ratio of the capacitance of the external capacitor to that of the LCD and can reach 50%. An experiment on a prototype demonstrates an almost 30% reduction with large 1-pixel LCDs. With a small 10 × 10mm2 LCD, the overhead of the micro-controller matches the reduction so no improvement could be measured. Though the technique requires longer time for polarity reversal, we confirm that it does not significantly degrade visual quality.
The use of an interface-planarization (IP) prism in millimeter-wave ellipsometry is proposed to achieve reproducible measurements of soft, protean, and non-flat samples. The complex relative dielectric constants of a slice of bovine tissue were successfully measured at frequencies from 90 to 140 GHz using the IP prism to confirm its applicability. The use of the IP prism was found to be advantageous for protecting the sample surface from the desiccation during the measurements.
Shinichiro NAKAMURA Shunsuke KOSHITA Masahide ABE Masayuki KAWAMATA
In this paper, we propose Affine Combination Lattice Algorithm (ACLA) as a new lattice-based adaptive notch filtering algorithm. The ACLA makes use of the affine combination of Regalia's Simplified Lattice Algorithm (SLA) and Lattice Gradient Algorithm (LGA). It is proved that the ACLA has faster convergence speed than the conventional lattice-based algorithms. We conduct this proof by means of theoretical analysis of the mean update term. Specifically, we show that the mean update term of the ACLA is always larger than that of the conventional algorithms. Simulation examples demonstrate the validity of this analytical result and the utility of the ACLA. In addition, we also derive the step-size bound for the ACLA. Furthermore, we show that this step-size bound is characterized by the gradient of the mean update term.
YoungKyu JANG Ik-Joon CHANG Jinsang KIM
PD-SOI (Partial Depleted Silicon On Insulator) process is a good candidate technology for space system designs, since it features excellent insulation to the silicon substrate compared to the conventional bulk CMOS process. However, the radioactive particles from the low earth orbit can causes single event transient (SET) or abrupt charge collection in a circuit node, leading to a logical error in space systems. Also, the side effects such as the history effect and the kink effect in PD-SOI technology cause the threshold voltage variation, degrading the circuit performance. We propose SET-tolerant PD-SOI CMOS logic circuits using a novel active body-bias scheme. Simulation results show that the proposed circuits are more effective to SET and the side effects as well.
Yun BU Tian Qian LI Qiang ZHANG
It is very difficult to know evolution state of ACO in its working. To solve the problem, we propose using colony entropy and mean colony entropy to monitor the algorithm. The two functions show fluctuation and declining trends depended on time t in a tour and iteration number. According to the principle, that each updated edge will get the same increment is improper. Then a weighted algorithm is proposed to calculate each arc's increment based on its selected probability. The strategy can provide more exploration to help to find the global optimum value, and experiments show its improved performance.
Xiaoyun WANG Jinsong ZHANG Masafumi NISHIDA Seiichi YAMAMOTO
This paper describes a novel method to improve the performance of second language speech recognition when the mother tongue of users is known. Considering that second language speech usually includes less fluent pronunciation and more frequent pronunciation mistakes, the authors propose using a reduced phoneme set generated by a phonetic decision tree (PDT)-based top-down sequential splitting method instead of the canonical one of the second language. The authors verify the efficacy of the proposed method using second language speech collected with a translation game type dialogue-based English CALL system. Experiments show that a speech recognizer achieved higher recognition accuracy with the reduced phoneme set than with the canonical phoneme set.
Operating system (OS) reboots are an essential part of updating kernels and applications on laptops and desktop PCs. Long downtime during OS reboots severely disrupts users' computational activities. This long disruption discourages the users from conducting OS reboots, failing to enforce them to conduct software updates. Although the dynamic updatable techniques have been widely studied, making the system “reboot-free” is still difficult due to their several limitations. As a result, users cannot benefit from new functionality or better performance, and even worse, unfixed vulnerabilities can be exploited by attackers. This paper presents ShadowReboot, a virtual machine monitor (VMM)-based approach that shortens downtime of OS reboots in software updates. ShadowReboot conceals OS reboot activities from user's applications by spawning a VM dedicated to an OS reboot and systematically producing the rebooted state where the updated kernel and applications are ready for use. ShadowReboot provides an illusion to the users that the guest OS travels forward in time to the rebooted state. ShadowReboot offers the following advantages. It can be used to apply patches to the kernels and even system configuration updates. Next, it does not require any special patch requiring detailed knowledge about the target kernels. Lastly, it does not require any target kernel modification. We implemented a prototype in VirtualBox 4.0.10 OSE. Our experimental results show that ShadowReboot successfully updated software on unmodified commodity OS kernels and shortened the downtime of commodity OS reboots on five Linux distributions (Fedora, Ubuntu, Gentoo, Cent, and SUSE) by 91 to 98%.
Kwang-Hoon KIM Young-Seok CHOI Seong-Eun KIM Woo-Jin SONG
We present a low-complexity complementary pair affine projection (CP-AP) adaptive filter which employs the intermittent update of the filter coefficients. To achieve both a fast convergence rate and a small residual error, we use a scheme combining fast and slow AP filters, while significantly reducing the computational complexity. By employing an evolutionary method which automatically determines the update intervals, the update frequencies of the two constituent filters are significantly decreased. Experimental results show that the proposed CP-AP adaptive filter has an advantage over conventional adaptive filters with a parallel structure in that it has a similar convergence performance with a substantial reduction in the total number of updates.
Mingzhe RONG Tianhui LI Xiaohua WANG Dingxin LIU Anxue ZHANG
When ultra-high-frequency (UHF) method is applied in partial discharge (PD) detection for GIS, the propagation process and rules of electromagnetic (EM) wave need to be understood clearly for conducting diagnosis and assessment about the real insulation status. The preceding researches are mainly concerning about the radial component of the UHF signal, but the propagation of the signal components in axial and radial directions and that perpendicular to the radial direction of the GIS tank are rarely considered. So in this paper, for a 252,kV GIS with T-shaped structure (TS), the propagation and attenuation of PD-induced EM wave in different circumferential angles and directions are investigated profoundly in time and frequency domain based on Finite Difference Time Domain (FDTD) method. The attenuation rules of the peak to peak value (Vpp) and cumulative energy are concluded. By comparing the results of straight branch and T branch, the influence of T-shaped structure over the propagation of different signal components are summarized. Moreover, the new circumferential and axial location methods proposed in the previous work are verified to be still applicable. This paper discusses the propagation mechanism of UHF signal in T-shaped tank, which provides some referential significance towards the utilization of UHF technique and better implementation of PD detection.
Beong-Ha LIM Gun-Su KIM Dong-Ho LEE Heung-Sik TAE Seok-Hyun LEE
This paper proposes a new address method to reduce the address power consumption in an AC plasma panel display (AC-PDP). We apply an overlap scan method, in which the scan pulse overlaps with those of the previous scan time and the next scan time. The overlap scan method decreases the address voltage and consequently reduces the address power consumption. However, the drawback of this method is the narrow address voltage margin. This occurs because the maximum address voltage decreases much more than the minimum address voltage does. In order to increase the address voltage margin, we apply a two-step address voltage waveform, in the overlap scan method. In this case, the maximum address voltage increases; however, the minimum address voltage is almost the same. This leads to a wide address voltage margin. Moreover, the two-step address voltage waveform reduces the address power consumption, because the address voltage rises and falls in two steps using an energy recovery capacitor. Consequently, the experimental results show that the new address method reduces the address power consumption by 19.6,Wh (58%) when compared with the conventional method.
Two types of low-coherence millimeter-wave sources for photonic millimeter-wave ellipsometry are compared. A broadband signal (125-GHz bandwidth) or a narrowband one (0.5-GHz bandwidth) is used to measure the complex relative dielectric constants of purified water, and the narrowband signal is revealed to be suitable for accurate measurement.
Hiroshi YAMADA Shuntaro TONOSAKI Kenji KONO
Infrastructure as a Service (IaaS), a form of cloud computing, is gaining attention for its ability to enable efficient server administration in dynamic workload environments. In such environments, however, updating the software stack or content files of virtual machines (VMs) is a time-consuming task, discouraging administrators from frequently enhancing their services and fixing security holes. This is because the administrator has to upload the whole new disk image to the cloud platform via the Internet, which is not yet fast enough that large amounts of data can be transferred smoothly. Although the administrator can apply incremental updates directly to the running VMs, he or she has to carefully consider the type of update and perform operations on all running VMs, such as application restarts. This is a tedious and error-prone task. This paper presents a technique for synchronizing VMs with less time and lower administrative burden. We introduce the Virtual Disk Image Repository, which runs on the cloud platform and automatically updates the virtual disk image and the running VMs with only the incremental update information. We also show a mechanism that performs necessary operations on the running VM such as restarting server processes, based on the types of files that are updated. We implement a prototype on Linux 2.6.31.14 and Amazon Elastic Compute Cloud. An experiment shows that our technique can synchronize VMs in an order-of-magnitude shorter time than the conventional disk-image-based VM method. Also, we discuss limitations of our technique and some directions for more efficient VM updates.
Ken HIRAGA Kazumitsu SAKAMOTO Kentaro NISHIMORI Tomohiro SEKI Tadao NAKAGAWA Kazuhiro UEHARA
One of the procedures for increasing the number of multi-input and multi-output (MIMO) branches without increasing the computational cost for MIMO detection or multiplexing is to exploit parallel transmissions by using polarization multiplexing. In this paper the effectiveness of using polarization multiplexing is confirmed under the existence of polarization rotation, which is inevitably present in short-range multi-input and multi-output (SR-MIMO) channels with planar array antennas. It is confirmed that 8×8 SR-MIMO transmission system with polarization multiplexing has 60bit/s/Hz of channel capacity. This paper also shows a model for theoretical cross polarization discrimination (XPD) degradation, which is useful to calculate XPD degradations on diagonal paths.
Koh YAMANAGA Shiho HAGIWARA Ryo TAKAHASHI Kazuya MASU Takashi SATO
In this paper, the measurement of capacitance variation, of an on-chip power distribution network (PDN) due to the change of internal states of a CMOS logic circuit, is studied. A state-dependent PDN-capacitance model that explains measurement results will be also proposed. The model is composed of capacitance elements related to MOS transistors, signal and power supply wires, and substrate. Reflecting the changes of electrode potentials, the capacitance elements become state-dependent. The capacitive elements are then all connected in parallel between power supply and ground to form the proposed model. By using the proposed model, state-dependence of PDN-capacitances for different logic circuits are studied in detail. The change of PDN-capacitance exceeds 12% of its total capacitance in some cases, which corresponds to 6% shift of anti-resonance frequency. Consideration of the state-dependence is important for modeling the PDN-capacitance.
In this letter, we propose an improvement on a knapsack probabilistic encryption scheme [B. Wang, Q. Wu, Y. Hu, Information Sciences 177 (2007)], which was shown vulnerable to attacks due to Youssef [A.M. Youssef, Information Sciences 179 (2009)] and Lee [M.S. Lee, Information Sciences 222 (2013)], respectively. The modified encryption scheme is secure against Youssef's and Lee's attacks only at the costs of slightly compromising the efficiency of the original proposal.
Mitsuru OHTAKE Kousuke TOBARI Masaaki FUTAMOTO
Co/Pd multilayer films are prepared on fcc-Pd underlayers of (001), (011), and (111) orientations hetero-epitaxially grown on MgO single-crystal substrates at room temperature. The effects of underlayer orientation, Co and Pd layer thicknesses, and repetition number of Co/Pd bi-layer on the structure and the magnetic properties are investigated. fcc-Co/fcc-Pd multilayer films of (001), (011), and (111) orientations epitaxially grow on the Pd underlayers of (001), (011), and (111) orientations, respectively. Flatter and sharper Co/Pd interface is formed in the order of (011) < (111) < (001) orientation. Atomic mixing around the Co/Pd interface is enhanced by deposition of thinner Co and Pd layers, and Co-Pd alloy phase is formed. With increasing the repetition number (decreasing the thicknesses of Co and Pd layers), perpendicular magnetic anisotropy is promoted. Stronger perpendicular anisotropy is observed in the order of film orientation of (001) < (011) < (111). Perpendicular anisotropy of Co/Pd multilayer film is considered to be originated from the two sources; the interface anisotropy and the magnetocrystalline anisotropy associated with Co-Pd lattice shrinkage along the perpendicular direction. In order to enhance the perpendicular anisotropy of Co/Pd multilayer film, it is important to align the film orientation to be (111) and to enhance the lattice distortion along the perpendicular direction.
Guohuan HUA Hualong ZHUANG Shen XU Weifeng SUN Zhiqun LI
Two voltage controlled current source (VCCS) models of double-channel p-type lateral extended drain MOS (DPLEDMOS) are firstly proposed to analyze the energy recovery circuit (ERC) efficiency of PDP data driver IC. In terms of the mathematical function between ID and VDS, the VCCS models are created. The presented models can be embedded in system software Saber to simulate the ERC waveform of data driver IC. A test board and a PDP system are used to verify the accuracy of the VCCS models. The experimental measurements agree with the simulation results very well and the maximum model error is 3.89%. Simulation results also show that the ERC efficiency of PDP data driver IC is influenced by three factors: the value of charge time TERC, the drain current ID, and the capacitance of CL. In an actual PDP system, TERC is restricted and CL is changeless. The ERC efficiency of PDP data driver IC can be improved significantly by using DPLEDMOS which has higher ID capacity. The proposed VCCS models of DPLEDMOS can be used to predict the ERC efficiency accurately.
Seong-Eun KIM Young-Seok CHOI Jae-Woo LEE Woo-Jin SONG
This paper provides a novel normalized sign least-mean square (NSLMS) algorithm which updates only a part of the filter coefficients and simultaneously performs sparse updates with the goal of reducing computational complexity. A combination of the partial-update scheme and the set-membership framework is incorporated into the context of L∞-norm adaptive filtering, thus yielding computational efficiency. For the stabilized convergence, we formulate a robust update recursion by imposing an upper bound of a step size. Furthermore, we analyzed a mean-square stability of the proposed algorithm for white input signals. Experimental results show that the proposed low-complexity NSLMS algorithm has similar convergence performance with greatly reduced computational complexity compared to the partial-update NSLMS, and is comparable to the set-membership partial-update NLMS.
The performance of a mobile database management system (DBMS) in which most queries are made up of random data accesses if the NAND flash memory is used as storage media of the DBMS is degraded. The reason for this is that the performance of NAND flash memory is good for writing sequentially but poor when writing randomly. Thus, a new storage structure and querying policies are needed in mobile DBMS when flash memory is used as the storage media. In this letter, we propose a new policy of database page management to enhance the frequent random update performance, and then evaluate the performance experimentally.
This paper describes two promising millimeter-wave measurement techniques suitable for biological materials. One is reflection-geometry imaging using a low-coherence signal, and the other is millimeter-wave ellipsometry. Imaging porcine tissue during the desiccation process, we found the temporal variation of the reflection intensity to be well explained by an exponential decrease of the relative dielectric constant. Ellipsometry results showed that the complex relative dielectric constant also decreased exponentially with time during the desiccation process and that for bovine tissue the gradients for the real and imaginary parts of the constant were different. The implications of these results on the distribution of water in biological tissues are discussed.