Ultra-wideband pulse radar is a promising technology for the imaging sensors of rescue robots operating in disaster scenarios, where optical sensors are not applicable because of thick smog or high-density gas. For the above application, while one promising ultra-wideband radar imaging algorithm for a target with arbitrary motion has already been proposed with a compact observation model, it is based on an ellipsoidal approximation of the target boundary, and is difficult to apply to complex target shapes. To tackle the above problem, this paper proposes a non-parametric and robust imaging algorithm for a target with arbitrary motion including rotation and translation being observed by multi-static radar, which is based on the matching of target boundary points obtained by the range points migration (RPM) algorithm extended to the multi-static radar model. To enhance the imaging accuracy in situations having lower signal-to-noise ratios, the proposed method also adopts an integration scheme for the obtained range points, the antenna location part of which is correctly compensated for the estimated target motion. Results from numerical simulations show that the proposed method accurately extracts the surface of a moving target, and estimates the motion of the target, without any target or motion model.

This paper introduces amplitude-only images to image trading systems in which not only the copyright of images but also the privacy of consumers are protected. In the latest framework for image trading systems, an image is divided into an unrecognizable piece and a recognizable but distorted piece to simultaneously protect the privacy of a consumer and the copyright of the image. The proposed scheme uses amplitude-only images which are completely unrecognizable as the former piece, whereas the conventional schemes leave recognizable parts to the piece which degrades privacy protection performance. Moreover, the proposed scheme improves the robustness against copyright violation regardless of the used digital fingerprinting technique, because an amplitude-only image is larger than the piece in the conventional scheme. In addition, phase-only image is used as the second piece in the proposed scheme, the consumer can confirm what he/she bought. Experimental results show the effectiveness of the proposed scheme.

Application-Specific Network-on-Chips (ASNoCs) have been proposed as a more promising solution than regular NoCs to the global communication challenges for particular applications in nanoscale System-on-Chip (SoC) designs. In ASNoC Design, one of the key challenges is to generate the most suitable and power efficient NoC topology under the constraints of the application specification. In this work, we present a two-step floorplanning (TSF) algorithm, integrating topology synthesis into floorplanning phase, to automate the synthesis of such ASNoC topologies. At the first-step floorplanning, during the simulated annealing, we explore the optimal positions and clustering of cores and implement an incremental path allocation algorithm to predictively evaluate the power consumption of the generated NoC topology. At the second-step floorplanning, we explore the optimal positions of switches and network interfaces on the floorplan. A power and timing aware path allocation algorithm is also integrated into this step to determine the connectivity across different switches. Experimental results on a variety of benchmarks show that our algorithm can produce greatly improved solutions over the latest works.

This paper proposes an adaptation method for structuring elements of morphological filters. A structuring element of a morphological filter specifies a shape of local structures that is eliminated or preserved in the output. The adaptation of the structuring element is hence a crucial problem for image denoising using morphological filters. Existing adaptation methods for structuring elements require preliminary training using example images. We propose an adaptation method for structuring elements of morphological opening filters that does not require such training. In our approach, the opening filter is interpreted as an approximation method with the union of the structuring elements. In order to eliminate noise components, a penalty defined from an assumption of image smoothness is imposed on the structuring element. Image denoising is achieved through decreasing the objective function, which is the sum of an approximation error term and the penalty function. In experiments, we use the proposed method to demonstrate positive impulsive noise reduction from images.

This paper describes the design of an interpolated pipeline analog-to-digital converter (ADC). By introducing the interpolation technique into the conventional pipeline topology, it becomes possible to realize a more than 10-bits resolution and several hundred MS/s ADC using low-gain open-loop amplifiers without any multiplying digital-to-analog converter (MDAC) calibration. In this paper, linearity requirement of the amplifier is analyzed with the relation of reference range and stage resolution first. Noise characteristic is also discussed with amplifier's noise bandwidth and load capacitance. After that, sampling speed and SNR characteristic are examined with various amplifier currents. Next, the resolution optimization of the pipeline stage is discussed based on the power consumption. Through the analysis, reasonable parameters for the amplifier can be defined, such as transconductance, source degeneration resistance and load capacitance. Also, optimized operating speed and stage resolution for interpolated pipelined ADC is shown. The analysis in this paper is valuable to both the design of interpolated pipeline ADCs and other circuits which incorporate interpolation and amplifiers.

UWB (Ultra Wideband) radar offers great promise for advanced near field sensors due to its high range resolution. In particular, it is suitable for rescue or resource exploration robots, which need to identify a target in low visibility or acoustically harsh environments. Recently, radar algorithms that actively coordinate multiple scattered components have been developed to enhance the imaging range beyond what can be achieved by synthesizing a single scattered component. Although we previously developed an accurate algorithm for imaging shadow regions with low computational complexity using derivatives of observed ranges for double scattered signals, the algorithm yields inaccurate images under the severe interference situations that occur with complex-shaped or multiple objects or in noisy environments. This is because small range fluctuations arising from interference or random noises can produce non-negligible image degradation owing to inaccuracy in the range derivative calculation. As a solution to this difficulty, this paper proposes a novel imaging algorithm that does not use the range derivatives of doubly scattered signals, and instead extracts a feature of expansive distributions of the observed ranges, using a unique property inherent to the doubly scattering mechanism. Numerical simulation examples of complex-shaped or multiple targets are presented to demonstrate the distinct advantage of the proposed algorithm which creates more accurate images even for complicated objects or in noisy situations.

During the production of speech signals, the vowel onset point is an important event containing important information for many speech processing tasks, such as consonant-vowel unit recognition and speech end-points detection. In order to realize accurate automatic detection of vowel onset points, this paper proposes a reliable method using the energy characteristics of homomorphic filtered spectral peaks. The homomorphic filtering helps to separate the slowly varying vocal tract system characteristics from the rapidly fluctuating excitation characteristics in the cepstral domain. The distinct vocal tract shape related to vowels is obtained and the peaks in the estimated vocal tract spectrum provide accurate and stable information for VOP detection. Performance of the proposed method is compared with the existing method which uses the combination of evidence from the excitation source, spectral peaks, and modulation spectrum energies. The detection rate with different time resolutions, together with the missing rate and spurious rate, are used for comprehensive evaluation of the performance on continuous speech taken from the TIMIT database. The detection accuracy of the proposed method is 74.14% for ±10 ms resolution and it increases to 96.33% for ±40 ms resolution with 3.67% missing error and 4.14% spurious error, much better than the results obtained by the combined approach at each specified time resolution, especially the higher resolutions of ±10±30 ms. In the cases of speech corrupted by white noise, pink noise and f-16 noise, the proposed method also shows significant improvement in the performance compared with the existing method.

In order to improve user's privacy in multi-authority Attribute-Based Encryption (ABE), we propose a solution which hides user's attributes by privacy homomorphism, such that not only the “external” adversary fails to access the private attribute of one user by eavesdropping on communications, but also the “internal” Attribute Authorities (AA), who are responsible for issuing attribute keys, are unable to build a full profile with all of the user's attributes by pooling their information on the user's ID. Meanwhile, the use of ID is essential to defend against collusion attack on ABE. Benefiting from privacy homomorphism, by which we distribute the part of the interpolation for the shares abstracted by the hidden attributes into each AA, the performance of the proposed scheme is higher than those of existing ABE schemes.

A 6-bit, 7 mW, 700 MS/s subranging ADC using Capacitive DAC (CDAC) and gate-weighted interpolation fabricated in 90 nm CMOS technology is demonstrated. CDACs are used as a reference selection circuit instead of resistive DACs (RDAC) for reducing settling time and power dissipation. A gate-weighted interpolation scheme is also incorporated to the comparators, to reduce the circuit components, power dissipation and mismatch of conversion stages. By virtue of recent technology scaling, an interpolation can be realized in the saturation region with small error. A digital offset calibration technique using capacitor reduces comparator's offset voltage from 10 mV to 1.5 mV per sigma. Experimental results show that the proposed ADC achieves a SNDR of 34 dB with calibration and FoM is 250 fJ/conv., which is very attractive as an embedded IP for low power SoCs.

In our previous study, we proposed the waveform interpolation (WI) approach to model the excitation signals for hidden Markov model (HMM)-based speech synthesis. This letter presents several techniques to improve excitation modeling within the WI framework. We propose both the time domain and frequency domain zero padding techniques to reduce the spectral distortion inherent in the synthesized excitation signal. Furthermore, we apply non-negative matrix factorization (NMF) to obtain a low-dimensional representation of the excitation signals. From a number of experiments, including a subjective listening test, the proposed method has been found to enhance the performance of the conventional excitation modeling techniques.

Ultra wideband radar is one of the most promising techniques for non-invasive imaging in a dielectric medium, which is suitable for both medical screening and non-destructive testing applications. A novel imaging method for such an application is proposed in this brief paper, which has been extended from the advanced range points migration method to a multi-static observation model with circular arrays. One notable feature of this method is that it is applicable to either arbitrary dielectric or internal object shapes, and it can also expand the reconstructible image region compared with that obtained using the mono-static model by employing received signals after penetrating various propagation paths in dielectric medium. Numerical results for the investigation of an elliptical object, surrounded by a random dielectric surface, show the remarkable advantages of the proposed method with respect to image expansion.

A new wideband wave absorber with translucent structure using carbon fibers is presented in this paper. The absorber is composed of bundled short carbon fibers which are arranged in front of a back metal and a spacer. Absorption characteristics of the one-layered absorber showed that matching frequencies can be controlled by the thickness of the spacer and the length of the carbon fibers. To further improve the characteristics, multi-layered absorbers are designed with the same procedure as one-layered absorber. The designed absorber showed 15 dB absorption characteristics from 1.0 to 10.0 GHz. Then a small anechoic chamber with the inside dimension of 200 cm200 cm200 cm was fabricated using ninety-six proposed absorbers. The electrical power in the chamber was measured at 2.45 GHz and the results showed that the variation of the power was less than 4 dB inside a circle with radius of 60 cm as work space for electromagnetic measurements.

In this letter, an intra-field deinterlacing algorithm based on a gradient inverse weighted filtering (GIWF) interpolator is proposed. The proposed algorithm consists of three steps: We first interpolate the missing line with simple strategies in the working window. Then we calculate the coefficients of the gradient-weighted filters by exploiting the local gray gradients among the neighboring pixels. In the last step, we interpolate the missing line using the proposed GIWF interpolator. Experiments show that the proposed algorithm provides superior performances in terms of both objective and subjective image qualities.

Image warping is usually used to perform real-time geometric transformation of the images captured by the CMOS image sensor of video camera. Several existing look-up table (LUT)-based algorithms achieve real-time performance; however, the size of the LUT is still large, and it has to be stored in off-chip memory. To reduce latency and bandwidth due to the use of off-chip memory, this paper proposes an improved LUT (ILUT) scheme that compresses the LUT to the point that it can be stored in on-chip memory. First, a one-step transformation is adopted instead of using several on-line calculation stages. The memory size of the LUT is then reduced by utilizing the similarity of neighbor coordinates, as well as the symmetric characteristic of video camera images. Moreover, an elaborate pipeline hardware structure, cooperating with a novel 25-point interpolation algorithm, is proposed to accelerate the system and reduce further memory usage. The proposed system is implemented by a field-programmable gate array (FPGA)-based platform. Two different examples show that the proposed ILUT achieves real-time performance with small memory usage and low system requirements.

In recent years, there has been an increasing demand with regard to available elemental services provided by independent firms for compositing new services. Currently, however, whenever it is difficult to maintain the required level of quality of a new composite web service, assignment of the new computer's resources as provisioning at the data center is not always effective, especially in the area of performance for composite web service providers. Thus, a new approach might be required. This paper presents a new control method aiming to maintain the performance requirements for composite web services. There are three aspects of our method that are applied: first of all, the theory of constraints (TOC) proposed by E.M. Goldratt ; secondly, an evaluation process in the non-linear feed forward controlling method: and finally multiple trials in applying policies with verification. In particular, we will discuss the architectural and theoretical aspects of the method in detail, and will show the insufficiency of combining the feedback controlling approach with TOC as a result of our evaluation.

For effective use of the frequency band, carrier superposing (common band) technique has been introduced to satellite communication systems. On the other hand, satellite's TWTA (Traveling Wave Tube Amplifier) should be operated near its saturation level for power efficiency. However, the TWTA nonlinearity characteristics around that level causes interference in carrier superposing systems. Therefore in this paper, a post-compensation technique for TWTA nonlinear distortion is introduced and verified for practical use in a carrier superposed Point to Point satellite communication system which adopts interference canceller. Simulation results show that it is possible to reduce the bit error rate degradation over the entire range, especially at nonlinear operating point.

In this paper, we propose a novel texture analysis method capable of estimating multiple primitives, which are elements repetitively arranged to compose a texture, in multi-structured textures. The approach is based on a texture description model that uses mathematical morphology, called the “Primitive, Grain, and Point Configuration (PGPC)” texture model. The estimation of primitives based on the PGPC texture model involves searching the optimal structuring element for primitives according to a size distribution function and a magnification. The proposed method achieves the following two improvements: (1) the simultaneous estimation of a multiple number of primitives in multi-structured textures with a ranking of primitives on the basis of their significance. and (2) the introduction of flexibility in the process of magnification to obtain a higher degree of fitness of large grains. With a computational combination of different primitives, the method provides an ordered priority to denote the significance of elements. The promising performance of the proposed method is experimentally shown by a comparison with conventional methods.

Three-dimensional (3-D) reconstruction techniques employed by airborne radars are essential for object recognition in scenarios where optically vision is blurry, and are required for the monitoring of disasters and coast-guard patrols. There have been reports on 3-D reconstruction methods that exploit the layover appearing in inverse synthetic aperture radar (ISAR) imagery, which are suitable for the recognition of artificial targets such as buildings, aircraft or ships. However, existing methods assume only a point target or the aggregate of point targets, and most require the tracking of the multiple points over sequential ISAR images. In the case of a solid object with a continuous boundary, such as a wire or polyhedral structure, the positioning accuracy of such methods is severely degraded owing to scattering centers continuously shifting on the target surface with changes in the rotation angle. To overcome this difficulty, this paper extends the original Range Points Migration (RPM) method to the ISAR observation model, where a double mono-static model with two transmitting and receiving antennas is introduced to suppress cross-range ambiguity. The results of numerical simulation and experimental validation demonstrate that the extended RPM method has a distinct advantage for accurate 3-D imaging, even for non-point targets.

Heterogeneous resources such as configurable logic blocks (CLBs), multiplier blocks (MULs) and RAM blocks (RAMs) where millions of logic gates are included have been added to field programmable gate arrays (FPGAs). The fixed-outline floorplanning used by the existing methods always has a big penalty item in the objective function to ensure all the modules are placed in the specified chip region, which maybe greatly degrade the wirelength. This paper presents a three-phase floorplanning method for heterogeneous FPGAs. First, a non-slicing free-outline floorplanning method is used to optimize the wirelength, however, in this phase, the satisfaction of resource requirements from functional modules might fail. Second, a min-cost-max-flow algorithm is used to tune the assignment of CLBs to functional modules, and assign contiguous regions to each module so that all the functional modules satisfy CLB requirements. Finally, the MULs and RAMs are allocated to modules by a network flow model. CLBs hold the maximum quantity among all the resources. Therefore, making a high utilization of them means an enhancement of the FPGA densities. The proposed method can improve the utilization of CLBs, hence, much larger circuits could be mapped to the same FPGA chip. The results show that about 7–85% wirelength reduction is obtained, and CLB utilization is improved by about 25%.

Out-of-vocabulary (OOV) words create serious problems for automatic speech recognition (ASR) systems. Not only are they miss-recognized as in-vocabulary (IV) words with similar phonetics, but the error also causes further errors in nearby words. Language models (LMs) for most open vocabulary ASR systems treat OOV words as a single entity, ignoring the linguistic information. In this paper we present a class-based n-gram LM that is able to deal with OOV words by treating each of them individually without retraining all the LM parameters. OOV words are assigned to IV classes consisting of similar semantic meanings for IV words. The World Wide Web is used to acquire additional data for finding the relation between the OOV and IV words. An evaluation based on adjusted perplexity and word-error-rate was carried out on the Wall Street Journal corpus. The result suggests the preference of the use of multiple classes for OOV words, instead of one unknown class.