Jin-Fa LIN Yin-Tsung HWANG Ming-Hwa SHEU
A novel signal transition detector design using as few as 8 transistors is presented. The proposed design cleverly exploits the property of a specific internal state transition to mitigate the voltage degradation problem by employing only one extra transistor. It is thus capable of supporting level intact output signals and eliminating DC power consumption in the trailing buffer. The proposed design, featuring low circuit complexity and low power consumption, is considered useful for applications in self-timed circuits. Simulation results show that, when compared with other pass transistor logic based counterpart designs, as much as 46% savings in power and 28% in area can be achieved by the proposed design.
Suyong EUM Shin'ichi ARAKAWA Masayuki MURATA
Topological structure of peer-to-peer (P2P) networks affects their operating performance. Thus, various models have been proposed to construct an efficient topology for the P2P networks. However, due to the simultaneous failures of peers and other disastrous events, it is difficult to maintain the originally designed topological structure that provides the network with some performance benefits. For this reason, in this paper we propose a simple local rewiring method that changes the network topology to have small diameter as well as highly clustered structure. Moreover, the presented evaluation study shows how these topological properties are involved with the performance of P2P networks.
Ken-ichi SHINKAI Masanori HASHIMOTO Takao ONOYE
This paper investigates whether the self-heating effect in short intra-block wires will become apparent with technology scaling. These wires seem to have good thermal radiation characteristics, but we validate that the self-heating effect in local signal wires will be greater than that in optimal repeater-inserted global wires. Our numerical experiment shows that the maximum temperature increase from the silicon junction temperature will reach 40.4 in a steady state at a 14-nm process. Our attribution analysis also demonstrates that miniaturizing the area of wire cross-section exacerbates self-heating as well as using low-κ material and increased power dissipation in advanced technologies below 28 nm. It is revealed that the impact of self-heating on performance in local wires is limited, while underestimating the temperature may cause an unexpected reliability failure.
K. Habibul KABIR Masahiro SASABE Tetsuya TAKINE
Custody transfer in delay tolerant networks (DTNs) provides reliable end-to-end data delivery by delegating the responsibility of data transfer among special nodes (custodians) in a hop-by-hop manner. However, storage congestion occurs when data increases and/or the network is partitioned into multiple sub-networks for a long time. The storage congestion can be alleviated by message ferries which move around the network and proactively collect data from the custodians. In such a scenario, data should be aggregated to some custodians so that message ferries can collect them effectively. In this paper, we propose a scheme to aggregate data into selected custodians, called aggregators, in a fully distributed and autonomous manner with the help of evolutionary game theoretic approach. Through theoretical analysis and several simulation experiments, taking account of the uncooperative behavior of nodes, we show that aggregators can be selected in a self-organized manner and the number of aggregators can be controlled to a desired value.
Toshiki KANAMOTO Takaaki OKUMURA Katsuhiro FURUKAWA Hiroshi TAKAFUJI Atsushi KUROKAWA Koutaro HACHIYA Tsuyoshi SAKATA Masakazu TANAKA Hidenari NAKASHIMA Hiroo MASUDA Takashi SATO Masanori HASHIMOTO
This paper evaluates impact of self-heating in wire interconnection on signal propagation delay in an upcoming 32 nm process technology, using practical physical parameters. This paper examines a 64-bit data transmission model as one of the most heating cases. Experimental results show that the maximum wire temperature increase due to the self-heating appears in the case where the ratio of interconnect delay becomes largest compared to the driver delay. However, even in the most significant case which induces the maximum temperature rise of 11.0, the corresponding increase in the wire resistance is 1.99% and the resulting delay increase is only 1.15%, as for the assumed 32 nm process. A part of the impact reduction of wire self-heating on timing comes from the size-effect of nano-scale wires.
Marcus BRUNNER Henrik ABRAMOWICZ Norbert NIEBERT Luis M. CORREIA
In this paper, we describe several approaches to address the challenges of the network of the future. Our main hypothesis is that the Future Internet must be designed for the environment of applications and transport media of the 21st century, vastly different from the initial Internet's life space. One major requirement is the inherent support for mobile and wireless usage. A Future Internet should allow for the fast creation of diverse network designs and paradigms and must also support their co-existence at run-time. We detail the technical and business scenarios that lead the development in the EU FP7 4WARD project towards a framework for the Future Internet.
Naoki WAKAMIYA Masayuki MURATA
A new generation network is requested to accommodate an enormous number of heterogeneous nodes and a wide variety of traffic and applications. To achieve higher scalability, adaptability, and robustness than ever before, in this paper we present new network architecture composed of self-organizing entities. The architecture consists of the physical network layer, service overlay network layer, and common network layer mediating them. All network entities, i.e. nodes and networks, behave in a self-organizing manner, where the global behavior emerges through their operation on local information and direct and/or indirect mutual interaction. The center of the architecture is so-called self-organization engines, which implement nonlinear self-organizing dynamics originating in biology, physics, and mathematics. In this paper, we also show some examples of self-organization engines.
Daehwa PAIK Yusuke ASADA Masaya MIYAHARA Akira MATSUZAWA
This paper describes a flash ADC using interpolation (IP) and cyclic background self-calibrating techniques. The proposed IP technique that is cascade of capacitor IP and gate IP with dynamic double-tail latched comparator reduces non-linearity, power consumption, and occupied area. The cyclic background self-calibrating technique periodically suppresses offset mismatch voltages caused by static fluctuation and dynamic fluctuation due to temperature and supply voltage changes. The ADC has been fabricated in 90-nm 1P10M CMOS technology. Experimental results show that the ADC achieves SNDR of 6.07 bits without calibration and 6.74 bits with calibration up to 500 MHz input signal at sampling rate of 600 MSps. It dissipates 98.5 mW on 1.2-V supply. FoM is 1.54 pJ/conv.
Yoshihiro MAKIMOTO Hitoshi HIURA Nobuo GOTO Shin-ichiro YANAGIYA
In photonic label routing networks, recognition of optical labels is one of the key functions. We have proposed passive waveguide-type devices for recognition of optical labels coded in quadri-phase-shift-keying (QPSK) form. In this paper, we consider wavelength dependence of the devices. The basic module of the proposed device consists of a 3-dB directional coupler, two Y-junctions, and an asymmetric X-junction. The Y-junction and an asymmetric X-junction have basically no wavelength dependence. Although the 3-dB directional coupler has weak wavelength dependence, the device for two-symbol label recognition is found to work in wavelength 1.5-1.6 µm. The performance of the device is confirmed by simulation using beam propagation method (BPM).
Kanji TANAKA Ken-ichi SAEKI Mamoru MINAMI Takeshi UEDA
This paper presents a novel approach for robot localization using landmark maps. With recent progress in SLAM researches, it has become crucial for a robot to obtain and use large-size maps that are incrementally built by other mapper robots. Our localization approach successfully works with such incremental and large-size maps. In literature, RANSAC map-matching has been a promising approach for large-size maps. We extend the RANSAC map-matching so as to deal with incremental maps. We combine the incremental RANSAC with an incremental LSH database and develop a hybrid of the position-based and the appearance-based approaches. A series of experiments using radish dataset show promising results.
Chang-Soon CHOI Yozo SHOJI Hiroki OHTA
We present a 60-GHz wireless through-repeater system based on self-heterodyne transmission scheme with the potential to optimize the carrier-to-interference and noise ratio (CINR) performance according to the transmission distance. The phase-noise degradation through a 60-GHz repeater link is not a serious concern when we employ the self-heterodyne transmission scheme. Multichannel interferences caused by third-order intermodulation distortions are efficiently suppressed by setting a high power ratio of LO carrier to RF signals in the self-heterodyne transmission. However, this high power ratio results in a lower carrier-to-noise ratio (CNR) and becomes unsuitable for improving link performance if the transmission distance increases. In order to facilitate a solution, we propose and make an embodiment of 60 GHz self-heterodyne transmitters that provide flexible control over the power ratio of LO to RF in a range of 10 dB ranges. With them, we successfully demonstrate terrestrial digital broadcasting signals on five channels and optimize their performance for wireless through-repeater applications.
Our paper proposes a low power delay element with many other valuable characteristics for asynchronous circuits in the bundled-data implementation. Delay elements are frequently utilized to interact with asynchronous environment for revealing the current status of the bundled-data asynchronous circuits. Thus, a notable portion of the total energy is consumed by the delay elements for this kind of designs. Moreover, constructing a specific delay on a chip is a difficult task for recent CMOS technology. An extreme low power asymmetrical delay element with post-chip adjustment feature was developed mainly for solving these issues. Our initial intention was to develop a programmable delay element for asynchronous data path components. The proposed delay element is also suitable for many other applications requiring low power constraint. In addition to the programmability, the delay element also demonstrated efficiently characteristics such as good tolerance to process and temperature variations on the delay. Our delay element is equivalent to approximately the average power of a 4-stage inverter chain. A large delay can be obtained by cascaded scheme with nearly zero handshaking overhead. All arguments were cautiously verified by the post-layout simulation setup using TSMC 0.35 µm and 0.18 µm technologies under all extreme corners.
Masayuki UKISHIMA Hitomi KANEKO Toshiya NAKAGUCHI Norimichi TSUMURA Markku HAUTA-KASARI Jussi PARKKINEN Yoichi MIYAKE
Image quality of halftone print is significantly influenced by optical characteristics of paper. Light scattering in paper produces optical dot gain, which has a significant influence on the tone and color reproductions of halftone print. The light scattering can be quantified by the Modulation Transfer Function (MTF) of paper. Several methods have been proposed to measure the MTF of paper. However, these methods have problems in efficiency or accuracy in the measurement. In this article, a new method is proposed to measure the MTF of paper efficiently and accurately, and the dot gain effect on halftone print is analyzed. The MTF is calculated from the ratio in spatial frequency domain between the responses of incident pencil light to paper and the perfect specular reflector. Since the spatial frequency characteristic of input pencil light can be obtained from the response of perfect specular reflector, it does not need to produce the input illuminant having "ideal" impulse characteristic. Our method is experimentally efficient since only two images need to be measured. Besides it can measure accurately since the data can be approximated by the conventional MTF model. Next, we predict the reflectance distribution of halftone print using the measured MTF in microscopy in order to analyze the dot gain effect since it can clearly be observed in halftone micro-structure. Finally, a simulation is carried out to remove the light scattering effect from the predicted image. Since the simulated image is not affected by the optical dot gain, it can be applied to analyze the real dot coverage.
Ashraf M. Abdel HALEEM Masashi KATO Masaya ICHIMURA
Indium-sulfide-oxide thin films have been successfully deposited on indium-tin-oxide-coated glass from an aqueous solution containing Na2S2O3 and In2(SO4)3 by electrochemical deposition using a periodic 2-step-pulse voltage. The films have been annealed in nitrogen atmosphere for an hour at different temperatures; namely, 100, 200, 300 and 400. Then, the as-deposited and annealed films were characterized structurally, morphologically and optically. X-ray photoelectron spectroscopy (XPS) study was performed in order to understand the chemical states of the oxygen involved in the film composition. The photosensitivity was observed by means of photoelectrochemical measurements, which confirmed that the as-deposited and annealed films showed n-type conduction. Moreover, a heterostructure solar cell that has indium sulfide as a buffer layer and tin sulfide as an absorber was fabricated and characterized.
Takuya OHZONO Hirosato MONOBE Yo SHIMIZU
The self-organized microwrinkles can serve as a surface alignment layer to align nematic liquid crystals, which is primarily based on the groove mechanism. The azimuthal anchoring energy is discussed and estimated from the groove topography and the actual twist angle in the twisted nematic cell.
This paper clarifies the adequacy of the linear channel coding approach for Slepian-Wolf coding of individual sequences. A sufficient condition for ensembles of linear codes from which a universal Slepian-Wolf code can be constructed is given. Our result reveals that an ensemble of LDPC codes gives a universal code for Slepian-Wolf coding of individual sequences.
Kiyomoto-Fukushima-Tanaka proposed a perfectly anonymous attribute authentication scheme that realizes unidentifiable and untraceable authentication with offline revocation checking. The Kiyomoto-Fukushima-Tanaka scheme uses a self-blindable certificate that a user can change randomly. Thus, the certificate is modified for each authentication and the authentication scheme has the unidentifiable property and the untraceable property. However, in this letter, we show that the Kiyomoto-Fukushima-Tanaka scheme is insecure against the impersonation attack.
Self-Organizing Map (SOM) is a powerful tool for the exploratory of clustering methods. Clustering is the most important task in unsupervised learning and clustering validity is a major issue in cluster analysis. In this paper, a new clustering validity index is proposed to generate the clustering result of a two-level SOM. This is performed by using the separation rate of inter-cluster, the relative density of inter-cluster, and the cohesion rate of intra-cluster. The clustering validity index is proposed to find the optimal numbers of clusters and determine which two neighboring clusters can be merged in a hierarchical clustering of a two-level SOM. Experiments show that, the proposed algorithm is able to cluster data more accurately than the classical clustering algorithms which is based on a two-level SOM and is better able to find an optimal number of clusters by maximizing the clustering validity index.
Wei HONG Ke WU Hongjun TANG Jixin CHEN Peng CHEN Yujian CHENG Junfeng XU
In this paper, the research advances in SIW-like (Substrate Integrated Waveguide-like) guided wave structures and their applications in the State Key Laboratory of Millimeter Waves of China is reviewed. Our work is concerned with the investigations on the propagation characteristics of SIW, half-mode SIW (HMSIW) and the folded HMSIW (FHMSIW) as well as their applications in microwave and millimeter wave filters, diplexers, directional couplers, power dividers, antennas, power combiners, phase shifters and mixers etc. Selected results are presented to show the interesting features and advantages of those new techniques.
Masahiro KIMOTO Tatsuhiro TSUCHIYA Tohru KIKUNO
In this letter we give a lower bound on the worst-case time complexity of Dijkstra's three-state mutual exclusion algorithm by specifying a concrete behavior of the algorithm. We also show that our result is more accurate than the known best bound.