Rui HOU Tingting HE Mingming ZHENG Tengyue MAO
In this paper, we propose a controlled retransmission scheme in optical burst switching (OBS) networks. Different from previous works in the literature, we set a different value to retransmission probability at each contention and propose a retransmission analytical model for burst segmentation contention resolution scheme. In addition, we consider the effect of relevance in traffic come from multiple paths. We take into account the load at each link (include the given links and the other correlated links taking traffic) due to both the fresh and the retransmitted traffic and calculate the path blocking probability and the byte loss probability (ByLP) in cases of without and with full- wavelength conversion to evaluate the network performance. An extensive simulation is proposed to validate our analytical model, and results have shown that both path blocking probability and ByLP are affected by the load and the retransmission probability in each contention along a path and the correlated traffic carried links on the path.
Ryosuke KIKUCHI Satoshi USUI Kuniaki TANAKA Hiroaki USUI
Polyimide thin films were prepared by vapor-deposition polymerization. Naphthalene carboxylic dianhydride (NTCDA) was coevaporated with either diamino naphthalene (DAN) or diamino benzophenone (DAB). Coevaporation of dianhydride and diamines yielded thin films of polyamic acids. A polyimide thin film was obtained by annealing the codeposited film of NTCDA-DAB. On the other hand, the codeposited film of NTCDA-DAN was not imidized by annealing. In both cases, chemical structures of the products were not largely influenced by the molar ratio of depositing monomers if sufficient amount of diamine molecules are supplied in the coevaporation process.
Akira TAGUCHI Yoshikatsu HOSHI
While emphasizing the intensity or saturation component for getting high-quality color images, keeping the hue component unchanged is important; thus, perceptual color models such as HSI and HSV have been used. Hue-Saturation-Intensity (HSI) is a public color model, and many color applications are commonly based on this model. However, the transformation from the HSI color space to the RGB color space after processing intensity/saturation in the HSI color space usually generates the gamut problem. In this study, we clear the relationship between the RGB gamut and the HSI gamut completely. According to the result, we can check whether the processing result is located inside or outside of the RGB gamut without transforming to the RGB color space. If the processing result is judged outside of the RGB gamut, we apply the effective way of hue preserving correction algorithm which is proposed in this study to the saturation component. Experimental results demonstrate that the proposed algorithm can correct the color distortion caused by the enhancement without reducing the visual effect and it is especially useful for images with rich colors and local high component values.
Jigisha N PATEL Jerin JOSE Suprava PATNAIK
The concept of sparse representation is gaining momentum in image processing applications, especially in image compression, from last one decade. Sparse coding algorithms represent signals as a sparse linear combination of atoms of an overcomplete dictionary. Earlier works shows that sparse coding of images using learned dictionaries outperforms the JPEG standard for image compression. The conventional method of image compression based on sparse coding, though successful, does not adapting the compression rate based on the image local block characteristics. Here, we have proposed a new framework in which the image is classified into three classes by measuring the block activities followed by sparse coding each of the classes using dictionaries learned specific to each class. K-SVD algorithm has been used for dictionary learning. The sparse coefficients for each class are Huffman encoded and combined to form a single bit stream. The model imparts some rate-distortion attributes to compression as there is provision for setting a different constraint for each class depending on its characteristics. We analyse and compare this model with the conventional model. The outcomes are encouraging and the model makes way for an efficient sparse representation based image compression.
Nagayoshi YAMASHITA Masayuki NUMAO Ryutaro ICHISE
Since it is difficult to understand or predict research trends, we proposed methodologies for understanding and predicting research trends in the sciences, focusing on the structures of grants in the Japan Society for the Promotion of Science (JSPS), a Japanese funding agency. Grant applications are suitable for predicting research trends because these are research plans for the future, different from papers, which report research outcomes in the past. We investigated research trends in science focusing on research histories identified in grant application data of JSPS. Then we proposed a model for predicting research trends, assuming that breakthrough research encourages researchers to change from their current research field to an entirely new research field. Using breakthrough research, we aim to obtain higher precision in the prediction results. In our experimental results, we found that research fields in Informatics correlate well with actual scientific research trends. We also demonstrated that our prediction models are effective in actively interacting research areas, which include Informatics and Social Sciences.
Masashi KOUDA Ryuji HIRASE Takeshi YAMAO Shu HOTTA Yuji YOSHIDA
We deposited thin films of thiophene/phenylene co-oligomers (TPCOs) onto poly(tetrafluoroethylene) (PTFE) layers that were friction-transferred on substrates. These films were composed of aligned molecules in such a way that their polarizations of emissions and absorbances were larger along the drawing direction than those perpendicular to that direction. Organic field-effect transistors (OFETs) fabricated with these films indicated large mobilities, when the drawing direction of PTFE was parallel to the channel length direction. The friction-transfer technique forms the TPCO films that indicate the anisotropic optical and electronic properties.
Nobuo SATOH Shigetaka KATORI Kei KOBAYASHI Kazumi MATSUSHIGE Hirofumi YAMADA
We have investigated both the film thickness and surface potential of organic semiconductors deposited on two kinds of electrodes by the simultaneous observation with the dynamic force microscopy (DFM)/Kelvin-probe force microscope (KFM). To clarify the interfacial properties of organic semiconductor, we fabricated samples that imitated the organic light emitting diode (OLED) structure by depositing bis [$N,N '$-(1-naphthyl)-$N,N '$-phenyl] benzidine ($alpha$-NPD) and tris (8-hydroxyquinolinato) aluminum (Alq$_{3}$), respectively, on indium-tin-oxide (ITO) as anode and aluminum (Al) as cathode by the vacuum evaporation deposition using intersecting metal shadow masks. This deposition technique enables us to fabricate four different areas in the same substrate. The crossover area of the deposited thin films were measured by the DFM/KFM, the energy band diagrams were depicted and we considered that the charge behavior of the organic semiconductor depended on the material and the structure.
Yuuki MIYAZAKI Kazuo OKAMOTO Kenji OGINO
The novel ladder-shaped polydiacetylene with a terephthalamide linker in the molecular center, namely poly(TPh-bisDA) was synthesized by photo-polymerization. The characteristics of thin films of polymer were dependent upon a casting solvent, but no significant change of backbone conformation of the PDA was observed. Obtained film is expected to be applied to the semi-conducting materials for organic field effect transistors (OFET).
Keisuke KAWACHI Kazunari SHINBO Yasuo OHDAIRA Akira BABA Keizo KATO Futao KANEKO
A quartz-crystal-microbalance (QCM) and surface-plasmon-resonance (SPR) hybrid sensor was prepared, and the depositions of polymer electrolytes layer-by-layer (LbL) films were observed in situ. The estimated thicknesses obtained from the QCM method were different from those obtained from the SPR method. This was estimated to be caused by film swelling and water contained in the film.
Xi CHANG Zhuo ZHANG Yan LEI Jianjun ZHAO
Concurrency bugs do significantly affect system reliability. Although many efforts have been made to address this problem, there are still many bugs that cannot be detected because of the complexity of concurrent programs. Compared with atomicity violations, order violations are always neglected. Efficient and effective approaches to detecting order violations are therefore in urgent need. This paper presents a bidirectional predictive trace analysis approach, BIPED, which can detect order violations in parallel based on a recorded program execution. BIPED collects an expected-order execution trace into a layered bidirectional prediction model, which intensively represents two types of expected-order data flows in the bottom layer and combines the lock sets and the bidirectionally order constraints in the upper layer. BIPED then recognizes two types of candidate violation intervals driven by the bottom-layer model and then checks these recognized intervals bidirectionally based on the upper-layer constraint model. Consequently, concrete schedules can be generated to expose order violation bugs. Our experimental results show that BIPED can effectively detect real order violation bugs and the analysis speed is 2.3x-10.9x and 1.24x-1.8x relative to the state-of-the-art predictive dynamic analysis approaches and hybrid model based static prediction analysis approaches in terms of order violation bugs.
Tongjiang YAN Huadong LIU Yuhua SUN
In this paper, we modify the Legendre-Sidelnikov sequence which was defined by M. Su and A. Winterhof and consider its exact autocorrelation values. This new sequence is balanced for any p,q and proved to possess low autocorrelation values in most cases.
Nagisa OTAO Yoshihisa KISHIYAMA Kenichi HIGUCHI
This paper investigates the system-level throughput of non-orthogonal multiple access (NOMA) with a successive interference canceller (SIC) in the cellular downlink assuming proportional fair (PF)-based radio resource (bandwidth and transmission power) allocation. The purpose of this study is to examine the possibility of applying NOMA with a SIC to the systems beyond the 4G cellular system. Both the mean and cell-edge user throughput are important in a real system. PF-based scheduling is known to achieve a good tradeoff between them by maximizing the product of the user throughput among users within a cell. In NOMA with a SIC, the scheduler allocates the same frequency to multiple users simultaneously, which necessitates multiuser scheduling. To achieve a better tradeoff between the mean and cell-edge user throughput, we propose and compare three power allocation strategies among users, which are jointly implemented with multiuser scheduling. Extensive simulation results show that NOMA with a SIC with a moderate number of non-orthogonally multiplexed users significantly enhances the system-level throughput performance compared to orthogonal multiple access (OMA), which is widely used in 3.9 and 4G mobile communication systems.
Shuhei HORIO Keigo TAKEUCHI Tsutomu KAWABATA
For low-density parity-check codes, spatial coupling was proved to boost the performance of iterative decoding up to the optimal performance. As an application of spatial coupling, in this paper, bit-interleaved coded modulation (BICM) with spatially coupled (SC) interleaving — called SC-BICM — is considered to improve the performance of iterative channel estimation and decoding for block-fading channels. In the iterative receiver, feedback from the soft-in soft-out decoder is utilized to refine the initial channel estimates in linear minimum mean-squared error (LMMSE) channel estimation. Density evolution in the infinite-code-length limit implies that the SC-BICM allows the receiver to attain accurate channel estimates even when the pilot overhead for training is negligibly small. Furthermore, numerical simulations show that the SC-BICM can provide a steeper reduction in bit error rate than conventional BICM, as well as a significant improvement in the so-called waterfall performance for high rate systems.
Shujuan GAO Insuk KIM Seong Tae JHANG
Robust yet efficient techniques for detecting and tracking targets in infrared (IR) images are a significant component of automatic target recognition (ATR) systems. In our previous works, we have proposed infrared target detection and tracking systems based on sparse representation method. The proposed infrared target detection and tracking algorithms are based on sparse representation and Bayesian probabilistic techniques, respectively. In this paper, we adopt Naïve Bayes Nearest Neighbor (NBNN) that is an extremely simple, efficient algorithm that requires no training phase. State-of-the-art image classification techniques need a comprehensive learning and training step (e.g., using Boosting, SVM, etc.) In contrast, non-parametric Nearest Neighbor based image classifiers need no training time and they also have other more advantageous properties. Results of tracking in infrared sequences demonstrated that our algorithm is robust to illumination changes, and the tracking algorithm is found to be suitable for real-time tracking of a moving target in infrared sequences and its performance was quite good.
A new signed color distance for color-to-gray conversion is proposed. It is suited to reflect gradation and detailed color change in an input color image into an output monochrome image. Experiments show the effectiveness of the proposed distance.
Hao XIAO Ning WU Fen GE Guanyu ZHU Lei ZHOU
This paper presents a synchronization mechanism to effectively implement the lock and barrier protocols in a decentralized manner through explicit message passing. In the proposed solution, a simple and efficient synchronization control mechanism is proposed to support queued synchronization without contention. By using state-of-the-art Application-Specific Instruction-set Processor (ASIP) technology, we embed the synchronization functionality into a baseline processor, making the proposed mechanism feature ultra-low overhead. Experimental results show the proposed synchronization achieves ultra-low latency and almost ideal scalability when the number of processors increases.
Hayate KOJIMA Yoshinobu MAEDA Taishin NOMURA
We proposed a hard-wired CPG hardware network to reproduce the gaits of four-legged animals. It should reproduce walking and bounding, and they should be switchable with each other by changing the value of only one voltage.
Masaki TAKANASHI Satoshi MAKIDO
Providing images captured by an on-board camera to surrounding vehicles is an effective method to achieve smooth road traffic and to avoid traffic accidents. We consider providing images using WiFi technology based on the IEEE802.11p standard for vehicle-to-vehicle (V2V) communication media. We want to compress images to suppress communication traffic, because the communication capacity of the V2V system is strictly limited. However, there are difficulties in image compression and transmission using wireless communication especially in a vehicular broadcast environment, due to transmission errors caused by fading, packet collision, etc. In this letter, we propose an image transmission technique based on compressed sensing. Through computer simulations, we show that our proposed technique can achieve stable image reconstruction despite frequent packet error.
Zule XU Seungjong LEE Masaya MIYAHARA Akira MATSUZAWA
We present a time-to-digital converter (TDC) achieving sub-picosecond resolution and high precision for all-digital phase-locked-loops (ADPLLs). The basic idea is using a charge pump to translate time interval into charge, and a successive-approximation-register-analog-to-digital converter (SAR-ADC) to quantize the charge. With this less complex configuration, high resolution, high precision, low power, and small area can be achieved all together. We analyzed the noise contribution from the charge pump and describe detailed design and implementation for sizing the capacitor and transistors, with the awareness of noise and linearity. The analysis demonstrates the proposed TDC capable of sub-picosecond resolution and high precision. Two prototype chips were fabricated in 65nm CMOS with 0.06mm2, and 0.018mm2 core areas, respectively. The achieved resolutions are 0.84ps and 0.80ps, in 8-bit and 10-bit range, respectively. The measured single-shot-precisions range from 0.22 to 0.6ps, and from 0.66 to 1.04ps, respectively, showing consistent trends with the analysis. Compared with state-of-the-arts, best performance balance has been achieved.
Up until now, the best public key encryption with multi-dimensional range query (PKMDRQ) scheme has two problems which need to be resolved. One is that the scheme is selectively secure. The other is that the time of decryption is long. To address these problems, we present a method of converting a predicate encryption supporting inner product (IPE) scheme into a PKMDRQ scheme. By taking advantage of this approach, an instance is also proposed. The comparison between the previous work and ours shows that our scheme is more efficient over the time complexity. Moreover, our scheme is adaptively secure.