著者
小松 和暉 宮路 祐一 上原 秀幸
出版者
IEEE
雑誌
IEEE Transactions on Wireless Communications = IEEE Transactions on Wireless Communications (ISSN:15361276)
巻号頁・発行日
vol.17, no.6, pp.3768-3780, 2018-06
被引用文献数
26

This paper presents a basis function selection technique of a frequency-domain Hammerstein digital selfinterference canceller for in-band full-duplex communications. The power spectral density (PSD) of the nonlinear selfinterference signal is theoretically analyzed in detail, and a nonlinear self-interference PSD estimation method is developed. The proposed selection technique decides on the basis functions necessary for cancellation and relaxes the computational cost of the frequency-domain Hammerstein canceller based on the estimated PSD of the self-interference of each basis function. Furthermore, the convergence performance of the canceller is improved by the proposed selection technique. Simulation results are then presented, showing that the proposed technique can achieve similar cancellation performance compared with the original frequency-domain Hammerstein canceller and a time-domain nonlinear canceller. Additionally, it is shown that the proposed technique improves the computational cost and the convergence performance of the original frequency-domain Hammerstein canceller.
著者
Ihara Hiroyuki Imai Shunsuke Oyama Satoshi Kurihara Masahito
出版者
IEEE
巻号頁・発行日
pp.2182-2187, 2018
被引用文献数
1

Artificial intelligence has shown remarkable performance in perfect information games. However, it is still no match for human players when it comes to most imperfect information games. Information set Monte Carlo tree search (ISMCTS) has been developed to reduce the effects of strategy fusion caused by determinization of the imperfect information and demonstrated advantages over the conventional Monte Carlo tree search (MCTS) that uses determinization. Because ISMCTS has only been used for games with relatively simple structure, it is still unknown whether it works effectively for more complex games. In this study, we take Pok´emon as an example of a complex imperfect information game and implement a simulator to evaluate the effectiveness of ISMCTS. Experimental results show that ISMCTS outperforms the conventional MCTS that uses determinization.
著者
小松 和暉 宮路 祐一 上原 秀幸
出版者
IEEE
雑誌
IEEE Wireless Communications and Networking Conference (WCNC), San Francisco, CA, 2017 = IEEE Wireless Communications and Networking Conference (WCNC), San Francisco, CA, 2017 (ISSN:15582612)
巻号頁・発行日
pp.1-6, 2017
被引用文献数
12

In-band full-duplex communications have been spotlighted because they can double the spectral efficiency of the current wireless communication systems. However, it is necessary to mitigate the self-interference (SI). Currently, several time-domain and frequency-domain SI cancellers have been proposed. Timedomain SI cancellers are based on the parallel Hammerstein (PH) model, and they have good flexibility with high computational cost. In contrast, frequency-domain SI cancellers can achieve high cancellation performance with low computational cost but they have less flexibility than time-domain PH based SI cancellers. In this paper, we propose a frequency-domain SI canceller based on the PH model. The proposed scheme estimates the frequency response of the SI channel and regenerates SI signals by the overlap-save method. Therefore, the computational complexity of the proposed scheme is less than time-domain PH based SI canceller. The performance of the proposed scheme is assessed by equivalent baseband signal simulations of a fullduplex transceiver. As a result, the proposed scheme achieves high SI cancellation as the time-domain PH based SI canceller with low computational cost. In addition, the convergence performance of the proposed scheme is faster than the time-domain scheme.
著者
Harasaki Kouji Tsukuda Masanori Omura Ichiro
出版者
IEEE
雑誌
2021 33rd International Symposium on Power Semiconductor Devices and ICs (ISPSD) (ISSN:19460201)
巻号頁・発行日
pp.367-370, 2021-06-15
被引用文献数
1

Digital gate driving methods have been recently proposed to control the IGBT switching transient by dynamically changing the drive power according to the input digital pattern. It has been reported that both surge voltage suppression and turn-off loss reduction can be consistently achieved. In the prior papers, however, the effect is evaluated based on only one optimum point, so that the effect of digital gate driving technology have not been accurately benchmarked for practical use. In this paper, we proposed a new benchmarking method for digital gate driven IGBTs using an approach of Eoff-Vsurge Trade-off shifts. We applied the proposed method to 12 types of IGBT samples and analyzed the benchmarking results.
著者
Yu Jing Yamauchi Toshihiro
出版者
IEEE
雑誌
2013 IEEE 10th International Conference on High Performance Computing and Communications & 2013 IEEE International Conference on Embedded and Ubiquitous Computing
巻号頁・発行日
pp.1628-1633, 2013

Android applications that using WebView can load and display web pages. Furthermore, by using the APIs provided in WebView, Android applications can interact with web pages. The interaction allows JavaScript code within the web pages to access resources on the Android device by using the Java object, which is registered into WebView. If this WebView feature were exploited by an attacker, JavaScript code could be used to launch attacks, such as stealing from or tampering personal information in the device. To address these threats, we propose a method that performs access control on the security-sensitive APIs at the Java object level. The proposed method uses static analysis to identify these security-sensitive APIs, detects threats at runtime, and notifies the user if threats are detected, thereby preventing attacks from web pages.
著者
小松 和暉 宮路 祐一 上原 秀幸
出版者
IEEE
雑誌
IEEE Transactions on Wireless Communications = IEEE Transactions on Wireless Communications (ISSN:15361276)
巻号頁・発行日
vol.19, no.7, pp.4424-4438, 2020-07
被引用文献数
41

This paper presents an iterative estimation and cancellation technique for nonlinear in-band full-duplex transceivers with IQ imbalances and amplifier nonlinearities. The estimation process of the proposed scheme consists of three stages, namely, the channel response estimation, IQ imbalance estimation, and power amplifier and low-noise amplifier (LNA) nonlinearities estimation. For the estimation of the parameters and improvement of the accuracy, distortions are compensated by cancellation or inversion with the latest estimated parameters. On the one hand, the channel response is estimated on the time domain; on the other hand, the IQ imbalance and nonlinearities are estimated on the frequency domain for a more straightforward estimation and superior accuracy. In the cancellation process of the proposed scheme, the received signal is compensated with the estimated parameters of the LNA and receiver IQ imbalance before cancellation because the desired signal is received with a high-power self-interference and is distorted by the radiofrequency receiver impairments. Simulation results show that the proposed technique can achieve higher cancellation performance compared with the Hammerstein canceller when the LNA is saturated by the self-interference. Additionally, the performance of the proposed canceller converges much faster than that of the Hammerstein canceller.
著者
Yoshimoto Noriyuki Ogawa Kaoru Ogawa Satoshi
出版者
IEEE
雑誌
IEEE Transactions on Applied Superconductivity (ISSN:10518223)
巻号頁・発行日
vol.14, no.2, pp.1600-1603, 2004-01-01
被引用文献数
1

Novel self-organization molecules, n-mercapto-alkyl benzo-annelated tetrathiafulvalenes (BTTF), have been synthesized. Exposure of polycrystalline Au and oriented crystalline Au (111) surfaces to organic solution of the novel BTTF derivatives in high magnetic field results in the binding of the derivatives to Au and the formation of highly-oriented self-assembled monolayers (SAMs) with redox active tetrahia-fulvalene (TTF) unit. The electrochemical properties were confirmed in the monolayer state. A comparison between SAMs on polycrystalline Au having a rough surface andon oriented crystalline Au (111) having a flat surface suggested that the well-oriented alkyl-chain layers in the SAMs could be blockade for the electron transfer between the TTF unit and the Au substrate.
著者
山田 外史
出版者
IEEE
雑誌
IEEE Sensors Journal (ISSN:1530437X)
巻号頁・発行日
vol.7, no.3, pp.401-408, 2007-03
被引用文献数
34

Cancer is the most deadly disease in the world today. There is a variety of different treatment methods for cancer, including radiotherapy and chemotherapy with anticancer drugs that have been in use over a long period of time. Hyperthermia is one of the cancer treatment methods that utilizes the property that cancer cells are more sensitive to temperature than normal cells. The control of temperature is an important task in achieving success using this treatment method. This paper reports the development of a novel needle-type nanosensor based on the spin-valve giant magnetoresistive (SV-GMR) technique to measure the magnetic flux density inside the body via pricking the needle. The sensor has been fabricated. The modeling and experimental results of flux density measurement have been reported. From the information of flux density, the temperature rise can be estimated to permit the delivery of controlled heating to precisely defined locations in controlled hyperthermia cancer treatment. The actual experiment with human is under investigation. © 2007, IEEE. All rights reserved.Proceedings of the 1997 2nd International Conference on Power Electronics and Drive Systems, PEDS. Part 2 (of 2); Singapore, Singapore; ; 26 May 1997 through 29 May 1997; Code 47014
著者
向井 智彦 栗山 繁
出版者
IEEE
雑誌
Proceedings - 15th Pacific Conference on Computer Graphics and Applications, Pacific Graphics 2007
巻号頁・発行日
vol.15th, pp.9-17, 2007
被引用文献数
8

Interactive animation systems often use a level-of-detail(LOD) control to reduce the computational cost by eliminatingunperceivable details of the scene. Most methodsemploy a multiresolutional representation of animationand geometrical data, and adaptively change the accuracylevel according to the importance of each character.Multilinear analysis provides the efficient representation ofmultidimensional and multimodal data, including humanmotion data, based on statistical data correlations. Thispaper proposes a LOD control method of motion synthesiswith a multilinear model. Our method first extracts asmall number of principal components of motion samplesby analyzing three-mode correlations among joints, time,and samples using high-order singular value decomposition.A new motion is synthesized by interpolatingthe reduced components using geostatistics, where theprediction accuracy of the resulting motion is controlledby adaptively decreasing the data dimensionality. Weintroduce a hybrid algorithm to optimize the reductionsize and computational time according to the distancefrom the camera while maintaining visual quality. Ourmethod provides a practical tool for creating an interactiveanimation of many characters while ensuring accurate andflexible controls at a modest level of computational cost.
著者
Ikeda H. Sano N.
出版者
IEEE
雑誌
IEEE transactions on electron devices (ISSN:00189383)
巻号頁・発行日
vol.60, no.10, pp.3417-3423, 2013-10

We propose a surface potential-based polycrystalline silicon thin-film transistors (poly-Si TFTs) compact model considering a nonequilibrium state. A drain current model considers grain boundary (GB) trap-related physical phenomena: composite mobility of GB and intragrain, GB bias-induced mobility modulation, transient behavior because of carrier capture and emission at GBs, pinch off voltage lowering, and GB trap-assisted leakage current. Besides, photoinduced current behavior is also considered by introducing quasi-Fermi potential. A capacitance model is derived from physically partitioned terminal charges and coupled to the drain current. This compact model allows us to accurately simulate static characteristics of various types of poly-Si TFTs, including temperature and luminance dependence. Furthermore, it succeeded to simulate frequency dependence of circuit performance derived from the trap-related transient behavior, which was verified by evaluating delay time in a 21-stage inverter chain.
著者
Sandhu A.S. Tong Xiao-Min
出版者
IEEE
雑誌
IEEE journal of selected topics in quantum electronics (ISSN:1077260X)
巻号頁・発行日
vol.18, no.1, pp.351-362, 2012
被引用文献数
1 2

Attosecond-duration, fully coherent, extreme-ultraviolet (XUV) photon bursts obtained through laser high-harmonic generation have opened up new possibilities in the study of atomic and molecular dynamics. We discuss experiments elucidating some of the interesting energy redistribution mechanisms that follow the interaction of a high-energy photon with a molecule. The crucial role of synchronized, strong-field, near-IR laser pulses in XUV pump-probe spectroscopy is highlighted. We demonstrate that near-IR pulses can in fact be used to modify the atomic structure and control the electronic dynamics on attosecond timescales. Our measurements show that the Gouy phase slip in the interaction region plays a significant role in these attosecond experiments. We perform precision measurement of interferences between strong field-induced Floquet channels to extract the intensity and phase dependence of photoionization dynamics. Applications of emerging table-top ultrafast XUV sources in the study of core electron dynamics are also discussed.
著者
Iwamoto Mitsugu Koga Hiroki Yamamoto Hirosuke
出版者
IEEE
雑誌
IEEE transactions on information theory (ISSN:00189448)
巻号頁・発行日
vol.58, no.9, pp.6194-6206, 2012-09
被引用文献数
1

Coding theorems on a $(2,2)$-threshold scheme with an opponent are discussed in an asymptotic setup, where the opponent tries to impersonate one of the two participants. A situation is considered where $n$ secrets $S^{n}$ from a memoryless source is blockwisely encoded to two shares and the two shares are decoded to $S^{n}$ with permitting negligible decoding error. We introduce correlation level of the two shares and characterize the minimum attainable rates of the shares and a uniform random number for realizing a $(2, 2)$-threshold scheme that is secure against the impersonation attack by the opponent. It is shown that if the correlation level between the two shares equals to $ell geq 0$, the minimum attainable rates coincide with $H(S)+ell $, where $H(S)$ denotes the entropy of the source, and the maximum attainable exponent of the success probability of the impersonation attack equals to $ell $. It is also shown that a simple scheme using an ordinary $(2,2)$-threshold scheme attains all the bounds as well.
著者
Beuchat Jean-Luc Muller Jean-Michel
出版者
IEEE
雑誌
IEEE transactions on computers (ISSN:00189340)
巻号頁・発行日
vol.57, no.12, pp.1600-1613, 2008-12
被引用文献数
20 19

Since redundant number systems allow constant time addition, they are often at the heart of modular multipliers designed for public key cryptography (PKC) applications. Indeed, PKC involves large operands (160 to 1024 bits) and several researchers proposed carry-save or borrow-save algorithms. However, these number systems do not take advantage of the dedicated carry logic available in modern Field Programmable Gate Arrays (FPGAs). To overcome this problem, we suggest to perform modular multiplication in a high-radix carry-save number system, where a sum bit of the carry-save representation is replaced by a sum word. Two digits are then added by means of a small Carry-Ripple Adder (CRA). Furthermore, we propose an algorithm which selects the best high-radix carry-save representation for a given modulus, and generates a synthesizable VHDL description of the operator.