To meet the demand for light sources for on-chip optical interconnections, we demonstrate the continuous-wave (CW) operation of photonic-crystal (PhC) nanocavity lasers at up to 89.8 by using InP buried heterostructures (BH). The wavelength of a PhC laser can be precisely designed over a wide range exceeding 100 nm by controlling the lattice constant of the PhC. The dynamic responses of the PhC laser are also demonstrated with a 3-dB bandwidth of over 7.0 GHz at 66.2. These results reveal the laser's availability for application to wavelength division multiplexed (WDM) optical interconnection on CMOS chips. We discuss the total bandwidths of future on-chip optical interconnections, and report the capabilities of PhC lasers.

A novel fabrication approach for electrochemical sensing of nicotinamide adenine dinucleotide (NADH) using neutral red (NR) functinalized carbon nanotube/plasma-polymerized film composite electrode is reported. The configuration of sensing electrode was NR-functionalized CNTs sandwiched between two acetonitrile PPFs on sputtered gold thin film. The NR as an electron transfer mediator shuttles the electron from the CNT to gold electrode. Due to the synergistic effect between NR and CNT, the resulting electrode showed the lower detection potential and the larger sensitivity (current) than that of NR or CNT alone. The sensor revealed a sensitivity of 29 µA mM-1 cm-2 at +0.15 V vs. Ag/AgCl, linear dynamic range of 0.08–4.2 mM, a detection limit of 18 µM at S/N=3, and a response time of 7 s.

This letter proposes an efficient local descriptor for wide-baseline dense matching. It improves the existing Daisy descriptor by combining intensity-based Haar wavelet response with a new color-based ratio model. The color ratio model is invariant to changes of viewing direction, object geometry, and the direction, intensity and spectral power distribution of the illumination. The experiments show that our descriptor has high discriminative power and robustness.

A dual-core spot size converter (DC-SSC) is integrated with a lateral grating assisted lateral co-directional coupler (LGLC) tunable laser by using no additional complicated fabrication processes. The excess loss due to the DC-SSC is only 0.5 dB, and narrow full width half maximums (FWHMs) of vertical and horizontal far-field patterns (FFPs) produced by the laser are about 25° and 20°. This integration causes no degradations of the performance of the LGLC laser; in other words, it maintains good lasing characteristics, namely, wide tuning range of over 68 nm and SMSR of over 35 dB in the C-band under a 50 semi-cooled condition.

In this paper, we present an automatic vision-based traffic sign recognition system, which can detect and classify traffic signs at long distance under different lighting conditions. To realize this purpose, the traffic sign recognition is developed in an originally proposed dual-focal active camera system. In this system, a telephoto camera is equipped as an assistant of a wide angle camera. The telephoto camera can capture a high accuracy image for an object of interest in the view field of the wide angle camera. The image from the telephoto camera provides enough information for recognition when the accuracy of traffic sign is low from the wide angle camera. In the proposed system, the traffic sign detection and classification are processed separately for different images from the wide angle camera and telephoto camera. Besides, in order to detect traffic sign from complex background in different lighting conditions, we propose a type of color transformation which is invariant to light changing. This color transformation is conducted to highlight the pattern of traffic signs by reducing the complexity of background. Based on the color transformation, a multi-resolution detector with cascade mode is trained and used to locate traffic signs at low resolution in the image from the wide angle camera. After detection, the system actively captures a high accuracy image of each detected traffic sign by controlling the direction and exposure time of the telephoto camera based on the information from the wide angle camera. Moreover, in classification, a hierarchical classifier is constructed and used to recognize the detected traffic signs in the high accuracy image from the telephoto camera. Finally, based on the proposed system, a set of experiments in the domain of traffic sign recognition is presented. The experimental results demonstrate that the proposed system can effectively recognize traffic signs at low resolution in different lighting conditions.

Automatic thresholding is an important technique for rail defect detection, but traditional methods are not competent enough to fit the characteristics of this application. This paper proposes the Maximum Weighted Object Correlation (MWOC) thresholding method, fitting the features that rail images are unimodal and defect proportion is small. MWOC selects a threshold by optimizing the product of object correlation and the weight term that expresses the proportion of thresholded defects. Our experimental results demonstrate that MWOC achieves misclassification error of 0.85%, and outperforms the other well-established thresholding methods, including Otsu, maximum correlation thresholding, maximum entropy thresholding and valley-emphasis method, for the application of rail defect detection.

The existing routing protocols for the interplanetary backbone network did not consider future link connection and link congestion. A novel routing protocol named CAMARP for the interplanetary backbone network is proposed in this letter. We use wait delay to consider future link connection and make the best next hop selection. A load balancing mechanism is used to avoid congestion. The proposed method leads to a better and more efficient distribution of traffic, and also leads to lower packet drop rates and higher throughput. CAMARP demonstrates good performance in the experiment.

This paper proposes a high-precision, high-speed keypoint matching method using two-stage randomized trees (RTs). The keypoint classification uses conventional RTs for high-precision, real-time keypoint matching. However, the wide variety of view transformations for templates expressed by RTs make it diffidult to achieve high-precision classification for all transformations with a single RTs. To solve this problem, the proposed method classifies the template view transformations in the first stage and then, in the second stage, classifies the keypoints using the RTs that corresponds to each of the view transformations classified in the first stage. Testing demonstrated that the proposed method is 88.5% more precise than SIFT, and 63.5% more precise than using conventional RTs for images in which the viewpoint of the object is rotated by 70 degrees. We have also shown that the proposed method supports real-time keypoint matching at 12 fps.

With the wide usage of multispectral images, a fast efficient multidimensional clustering method becomes not only meaningful but also necessary. In general, to speed up the multidimensional images' analysis, a multidimensional feature vector should be transformed into a lower dimensional space. The Hilbert curve is a continuous one-to-one mapping from N-dimensional space to one-dimensional space, and can preserves neighborhood as much as possible. However, because the Hilbert curve is generated by a recurve division process, 'Boundary Effects' will happen, which means data that are close in N-dimensional space may not be close in one-dimensional Hilbert order. In this paper, a new efficient approach based on the space-filling curves is proposed for classifying multispectral satellite images. In order to remove 'Boundary Effects' of the Hilbert curve, multiple Hilbert curves, z curves, and the Pseudo-Hilbert curve are used jointly. The proposed method extracts category clusters from one-dimensional data without computing any distance in N-dimensional space. Furthermore, multispectral images can be analyzed hierarchically from coarse data distribution to fine data distribution in accordance with different application. The experimental results performed on LANDSAT data have demonstrated that the proposed method is efficient to manage the multispectral images and can be applied easily.

Wavelength demultiplexed light switching is numerically calculated in the variable index arrayed waveguide. Wavelength demultiplexed light is switched in 4 output ports by changing the refractive index of variable index arrayed waveguide with 16 array waveguides. In the calculation, the phase differences in each arrayed waveguide, and the diffraction in the star coupler are considered. In 4 output ports switching, numerically calculated the refractive index changes of 16 array waveguides are numerically calculated to obtain the 24 switching pattern, and also calculated the crosstalk of each switching.

A differential pair of convergent and divergent lenses with adjustable lens spacing (“differential lens”) was devised as a varifocal lens and was successfully integrated into an object-space telecentric lens to build a focus mechanism with constant magnification. This integration was done by placing the front principal point of the varifocal lens at the rear focal point of the telecentric lens within a practical tolerance of positioning. Although the constant-magnification focus mechanism is a parallel projection system, a system for perfect perspective projection imaging without shifting the projection center during focusing could be built simply by properly setting this focus mechanism between an image-taking lens with image-space telecentricity and an image sensor. The focus resolution experimentally obtained was 0.92 µm (σ) for the parallel projection system with a depth range of 1.0 mm and this was 0.25 mm (σ) for the perspective projection system with a range from 120 to 350 mm within a desktop space. A marginal image resolution of 100 lp/mm was obtained with optical distortion of less than 0.2% in the parallel projection system. The differential lens could work up to 55 Hz for a sinusoidal change in lens spacing with a peak-to-valley amplitude of 425 µm when a tiny divergent lens that was plano-concave was translated by a piezoelectric positioner. Therefore, images that were entirely in focus were generated at a frame rate of 30 Hz for an object moving at a speed of around 150 mm/s in depth within the desk top space. Thus, three-dimensional (3-D) imaging that provided 3-D resolution based on fast focusing was accomplished in both microscopic and macroscopic spaces.

This paper proposes a method for reconstructing a smooth and accurate 3D surface. Recent machine vision techniques can reconstruct accurate 3D points and normals of an object. The reconstructed point cloud is used for generating its 3D surface by surface reconstruction. The more accurate the point cloud, the more correct the surface becomes. For improving the surface, how to integrate the advantages of existing techniques for point reconstruction is proposed. Specifically, robust and dense reconstruction with Shape-from-Silhouettes (SfS) and accurate stereo reconstruction are integrated. Unlike gradual shape shrinking by space carving, our method obtains 3D points by SfS and stereo independently and accepts the correct points reconstructed. Experimental results show the improvement by our method.

Existing pose estimation algorithms suffer from either low performance or heavy computation cost. In this letter, we present an approach to improve the attractive algorithm called Orthogonal Iteration. A new form of fundamental equations is derived which reduces the computation cost significantly. And paraperspective camera model is used instead of weak perspective camera model during initialization which improves the stability. Experiment results validate the accuracy and stability of the proposed algorithm and show that its computational complexity is favorably compare to the O(n) non-iterative algorithm.

In this paper, we introduce an approach of service adaptation for behavior mismatching services using pushdown model checking. This approach uses pushdown systems as model of adaptors so that capturing non-regular behavior in service interactions is possible. Also, the use of pushdown model checking integrates adaptation and verification. This guarantees that an adaptor generated by our approach not only solves behavior mismatches but also satisfies usual verification properties if specified. Unlike conventional approaches, we do not count on specifications of adaptor contracts but take only information from behavior interfaces of services and perform fully automated adaptor generation. Three requirements relating to behavior mismatches, unbounded messages, and branchings are retrieved from behavior interfaces and used to build LTL properties for pushdown model checking. Properties for unbounded messages, i.e., messages sent and received arbitrary multiple times, are especially addressed since it characterizes non-regular behavior in service composition. This paper also shows some experimental results from a prototype tool and provides directions for building BPEL adaptors from behavior interface of generated adaptor. The results show that our approach does solve behavior mismatches and successfully capture non-regular behavior in service composition under the scale of real service applications.

Visual degradation is usually introduced during 3D mesh simplification. The main issue in mesh simplification is to maximize the simplification ratio while minimizing the visual degradation. Therefore, effective and objective evaluation of the visual degradation is essential in order to select the simplification ratio. Some objective geometric and subjective perceptual metrics have been proposed. However, few objective metrics have taken human visual characteristics into consideration. To evaluate the visual degradation introduced by mesh simplification for a 3D triangular object, we integrate the structural degradation with mesh saliency and propose a new objective and multi-scale evaluation metric named Global Perceptual Structural Degradation (GPSD). The proper selection of the simplification ratio under a given distance-to-viewpoint is also discussed in this paper. The accuracy and validity of the proposed metric have been demonstrated through subjective experiments. The experimental results confirm that the GPSD metric shows better 3D model-based multi-scale perceptual evaluation capability.

We propose a new coding scheme for lossless bit rate reduction of the MPEG Surround module in unified speech and audio coding (USAC). The proposed scheme is based on context-adaptive arithmetic coding for efficient bit stream composition of spatial parameters. Experiments show that it achieves the significant lossless bit reduction of 9.93% to 12.14% for spatial parameters and 8.64% to 8.96% for the overall MPEG Surround bit streams compared to the original scheme. The proposed scheme, which is not currently included in USAC, can be used for the improved coding efficiency of MPEG Surround in USAC, where the saved bits can be utilized by the other modules in USAC.

This paper presents a novel design scheme for a band-switchable multi-band power amplifier (BS-MPA). A key point of the design scheme is configuring multi-section reconfigurable matching networks (MR-MNs) optimally in terms of low loss matching in multiple frequency bands from 0.7 to 2.5 GHz. The MR-MN consists of several matching sections, each of which has a matching block connected to a transmission line via a switch. Power dissipation at an actual on-state switch results in the insertion loss of the MR-MN and depends on how the impedance is transformed by the MR-MN. The proposed design scheme appropriately transforms the impedance of a high power transistor to configure a low loss MR-MN. Numerical analyses show quantitative improvement in the loss using the proposed scheme. A 9-band 3-stage BS-MPA is newly designed following the proposed scheme and fabricated on a multi-layer low temperature co-fired ceramic substrate for compactness. The BS-MPA achieves a gain of over 30 dB, an output power of greater than 33 dBm and a power added efficiency of over 40% at the supply voltage of 4 V in each operating band.

Several web sites providing disaster-related information failed repeatedly after the Great East Japan Earthquake, due to flash crowds caused by Twitter users. Twitter, which was intensively used for information sharing in the aftermath of the earthquake, relies on URL shorteners like bit.ly to offset its strict limit on message length. In order to mitigate the flash crowds, we examine the current Web usage and find that URL shorteners constitute a layer of indirection; a significant part of Web traffic is guided by them. This implies that flash crowds can be controlled by URL shorteners. We developed a new URL shortener, named rcdn.info, just after the earthquake; rcdn.info redirects users to a replica created on a CoralCDN, if the original site is likely to become overloaded. This surprisingly simple solution worked very well in the emergency. We also conduct a thorough analysis of the request log and present several views that capture user behavior in the emergency from various aspects. Interestingly, the traffic significantly grew up at previously unpopular (i.e., small) sites during the disaster; this traffic shift could lead to the failure of several sites. Finally, we show that rcdn.info has great potential in mitigating such failures. We believe that our experience will help the research community tackle future disasters.

Cubic TCP, one of transport protocols designed for high bandwidth-delay product (BDP) networks, has successfully been deployed in the Internet. Multi-homed computers with multiple interfaces to access the Internet via high speed links will become more popular. In this work, we introduce an extended version of Cubic TCP for multiple paths, called MPCubic. The extension process is approached from an analysis model of Cubic by using coordinated congestion control between paths. MPCubic can spread its traffic across paths in load-balancing manner, while preserving fair sharing with regular TCP, Cubic, and MPTCP at common bottlenecks. Moreover, to improve resilience to link failure, we propose a multipath fast recovery algorithm. The algorithm can significantly reduce the recovery time of data rate after restoration of failed links. These techniques can be useful for resilient high-bandwidth applications (for example, tele-health conference) in disaster-affected areas. Our simulation results show that MPCubic can achieve stability, throughput improvement, fairness, load-balancing, and quick data rate recovery from link failure under a variety of network conditions.