Some new generalized cyclotomic sequences defined by C. Ding and T. Helleseth are proven to exhibit a number of good randomness properties. In this paper, we determine the defining pairs of these sequences of length pm (p prime, m ≥ 2) with order two, then from which we obtain their trace representation. Thus their linear complexity can be derived using Key's method.

A solution-processed red-sensitive organic photoconductive device was demonstrated by using soluble nickel-phthalocyanine. We found that a ratio of four nickel-phthalocyanine regioisomers was important factor for the high optical-electrical conversion efficiency. A maximum external quantum efficiency of device of 0.83% was achieved by optimizing the device structure.

A CMOS detection procedure for ultra-wideband impulse radio (UWB-IR) communication system, employing Bi-Phase Shift Keying (BPSK) modulation scheme, is presented here. The chip was designed and fabricated in a 180 nm CMOS process and it requires a supply voltage of 1.8 V, with a die area of 0.01 mm2. A train of Gaussian Monocycle Pulses (GMP), modulated by a random data sequence of 1 Gb/s, has been detected successfully by the detector. Ability to process differential data without using conventional blocks like mixer, correlator etc. while consuming a very low power (3.8 pJ/bit for a data rate of 1 Gb/s) is the novelty of this work. The detection scheme employing a simple architecture with a noncoherent detection mechanism is well suited for UWB-IR communication system.

Semiconducting polymers, poly(1,4-phenylene) (PPP) and poly(4-diphenylaminostyrene) (PDAS), which are soluble to organic solvents, were synthesized and were deposited by means of electrospray deposition (ESD). The ESD generated spherical shells of diameters ranging from a few to several tens of microns. The shells consisted of coagulation of nanometric particles of the semiconducting polymers. Formation of the shells was largely influenced by the concentration of spray solution. It was also found that the formation of shells can be achieved with various types of soluble polymers.

Background subtraction is widely used in detecting moving objects; however, changing illumination conditions, color similarity, and real-time performance remain important problems. In this paper, we introduce a sequential method for adaptively estimating background components using Kalman filters, and a novel method for detecting objects using margined sign correlation (MSC). By applying MSC to our adaptive background model, the proposed system can perform object detection robustly and accurately. The proposed method is suitable for implementation on a graphics processing unit (GPU) and as such, the system realizes real-time performance efficiently. Experimental results demonstrate the performance of the proposed system.

This letter proposes a simple k-hop flooding scheme for the temporarily lost child node of a multicast tree in a mobile ad hoc network where a group of nodes move together within a bound. Through simulation, we show that our scheme improves the packet delivery ratio of MAODV to be comparable to the epidemic routing with only small additional duplicate packets.

Careful inspection of efficiency in a DC-DC converter and its dependence on different parameters have been key concerns for power electronic specialists for a long time ago. Although extensive research has been done on the estimation of power loss for different components in a DC-DC converter separately, there isn't any comprehensive study regarding power loss analysis in a DC-DC converter. In this research, detailed description and necessary considerations in order to analyze the power loss of all components in a Push-Pull DC-DC converter are presented. Push-Pull topology is the best choice for investigating efficiency issues, since it exhibits all different types of power loss that are usually encountered in DC-DC converters. This research proposes and verifies appropriate power loss models for all components in a DC-DC converter that dissipate power. For this purpose, conduction and switching loss models of all the relevant components are fully developed. The related equations are implemented in MATLAB environment to simulate all possible causes of power loss in the converter. In order to provide a test bed for evaluation of the proposed loss models and the converter efficiency, a 50 W Push-Pull DC-DC converter was designed and implemented. The experimental results are in full accordance with the simulation results in different input voltages, load conditions and switching frequencies. It was finally shown that the proposed models accurately estimate the DC-DC converter's efficiency.

This study focuses on speaker adaptation techniques for Computer-Assisted Language Learning (CALL). We first investigate the effects and problems of Maximum Likelihood Linear Regression (MLLR) speaker adaptation when used in pronunciation evaluation. Automatic scoring and error detection experiments are conducted on two publicly available databases of Japanese learners' English pronunciation. As we expected, over-adaptation causes misjudgment of pronunciation accuracy. Following the analysis, we propose a novel method, Regularized Maximum Likelihood Regression (Regularized-MLLR) adaptation, to solve the problem of the adverse effects of MLLR adaptation. This method uses a group of teachers' data to regularize learners' transformation matrices so that erroneous pronunciations will not be erroneously transformed as correct ones. We implement this idea in two ways: one is using the average of the teachers' transformation matrices as a constraint to MLLR, and the other is using linear combinations of the teachers' matrices to represent learners' transformations. Experimental results show that the proposed methods can better utilize MLLR adaptation and avoid over-adaptation.

In [1], Bellare, Boldyreva, and Micali addressed the security of public-key encryptions (PKEs) in a multi-user setting (called the BBM model in this paper). They showed that although the indistinguishability in the BBM model is induced from that in the conventional model, its reduction is far from tight in general, and this brings a serious key length problem. In this paper, we discuss PKE schemes in which the IND-CCA security in the BBM model can be obtained tightly from the IND-CCA security. We call such PKE schemes IND-CCA secure in the BBM model with invariant security reductions (briefly, SR-invariant IND-CCABBM secure). These schemes never suffer from the underlying key length problem in the BBM model. We present three instances of an SR-invariant IND-CCABBM secure PKE scheme: the first is based on the Fujisaki-Okamoto PKE scheme [7], the second is based on the Bellare-Rogaway PKE scheme [3], and the last is based on the Cramer-Shoup PKE scheme [5].

In situ observation of the adsorption process and the states of cytochrome c on glass/solution interfaces, and the functionality of the reduction reaction of adsorbed cytochorome c were performed by using slab optical waveguide (SOWG) spectroscopy. The peak position of the absorption band of cytochorome c adsorbed on a bare glass surface was almost the same as that of that in solution. The cytochorome c adsorbed on glass/solution interface was reduced by sodium dithionite solution. The adsorbed cytochorome c was still maintained its functionality after immobilization.

In a rooted triangulated planar graph, an outer vertex and two outer edges incident to it are designated as its root, respectively. Two plane embeddings of rooted triangulated planar graphs are defined to be equivalent if they admit an isomorphism such that the designated roots correspond to each other. Given a positive integer n, we give an O(n)-space and O(1)-time delay algorithm that generates all biconnected rooted triangulated planar graphs with at most n vertices without delivering two reflectively symmetric copies.

A min-max model predictive controller is developed in this paper for tracking control of wheeled mobile robots (WMRs) subject to the violation of nonholonomic constraints in an environment without obstacles. The problem is simplified by neglecting the vehicle dynamics and considering only the steering system. The linearized tracking-error kinematic model with the presence of uncertain disturbances is formed in the frame of the robot. And then, the control policy is derived from the worst-case optimization of a quadratic cost function, which penalizes the tracking error and control variables in each sampling time over a finite horizon. As a result, the input sequence must be feasible for all possible disturbance realizations. The performance of the control algorithm is verified via the computer simulations with a predefined trajectory and is compared to a common discrete-time sliding mode control law. The result shows that the proposed method has a better tracking performance and convergence.

A wideband, low noise, and highly linear transmitter for multi-mode radio is presented. Envelope injection scheme with a CMOS amplifier is developed to obtain sufficient linearity for complex modulation schemes such as OFDM, and to achieve low noise for concurrent operation of more than one standard. Active matching technique with doubly terminated LPF topology is also presented to realize wide bandwidth, low power consumption, and to eliminate off-chip components without increasing die area. A multi-mode transmitter is implemented in a 0.13 µm CMOS technology with an active area of 1.13 mm2. Third-order intermodulation product is improved by 17 dB at -3 dBm output by the envelope injection scheme. The transmitter achieves EVM of less than -29.5 dB at -3 dBm output from 0.2 to 7.2 GHz while consuming only 69 mW. The transmitter is also tested with multiple standards of UMTS, 802.11b, WiMax, 802.11a, and 802.11n, and satisfies EVM, ACLR, and spectrum specifications.

In bistatic radar, it is important to suppress the undesired signals such as the direct propagated signal from transmitter and its multipath components. Conventionally, some suppression methods have been proposed. They are categorized into the method using a feedback system and the method which subtracts the replicas of the undesired signals. The former method may have the problem on the convergence of the suppression performance. The latter method requires the precise delay times of the undesired signals. In this paper we propose a new method to detect the target in digital terrestrial TV-based bistatic radar which is based on orthogonal frequency division multiplexing (OFDM), without any information on the undesired signals' delay times. In the proposed method, we adapt a scheme based on maximum signal to noise ratio (MSN) algorithm, which makes signal to interference plus noise ratio (SINR) maximum for the desired signal component. The maximum sensitivity is steered so as to match the path that exhibits the delay which relates to the target position, as if the search beam is steered along the direction in array signal processing. In the proposed method, "nulls" are also formed for other delay components to be suppressed simultaneously. In the frequency domain, the carrier components of the scattered signal divided by those of the reference signal indicate the delays caused by scattering. We call these divided carrier components "normalized received signal." The steered sensitivity and nulls are created by the weight which is applied to the normalized received signal in the frequency domain. We obtain the method to estimate the weight to achieve the maximum SINR in the delay estimation which also includes the compensation for the reduction of the weight's length caused by decorrelation among the delay components. The simulation results show that our proposed method without any information on the undesired signal's delays provides sufficient detection performance for the typical target compared to the conventional one.

This paper describes a technique for reconstructing dynamic scene geometry using a handheld video projector-camera system and a single checkerboard image as a structured light pattern. The proposed technique automatically recognizes a dense checkerboard pattern under dynamic conditions. The pattern-recognition process is adaptive to different light conditions and an object's color, thereby avoiding the need to set threshold values manually for different objects when the scanning device is moving. We also propose a technique to find corresponding positions for the checkerboard pattern, when displayed by a projector, without needing any position-encoding techniques. The correspondence matching process is based on epipolar geometry, enabling the checkerboard pattern to be matched even if parts of it are occluded. By using a dense checkerboard pattern, we can construct a handheld projector-camera system that can acquire the geometry of objects in real time, and we have verified the feasibility of the proposed techniques.

Four-wave mixing (FWM) compensation using digital coherent detection is experimentally demonstrated. Two lights and the induced FWM components are combined with phase-locked local oscillator lights and received individually. The received signals are combined electrically and the signal-to-FWM crosstalk ratio is improved to more than 30 dB by backward propagation.

Ad Hoc Routing (AHR) was proposed to replace optimal routing in cluster-based multihop networks since it offers lower implementation complexity. However, this complexity reduction comes at the cost of an increase in the required transmission power. In addition, when the conventional distributed relay selection is applied to implement AHR, another increase in the required transmission power occurs due to the receiver selection error. In this paper, Ad Hoc Cooperative Routing (AHCR) that integrates the cooperative transmission with AHR is presented to reduce the difference between the required transmission power of AHR and that of optimal routing. Besides, Distributed Ad Hoc Cooperative Routing (DAHCR) scheme 1 that combines the cooperative transmission with AHR is proposed to reduce the difference between the required transmission power of DAHR and that of AHR. We then address the problem of DAHCR scheme 1 and propose DAHCR scheme 2. Simulation results show that the required transmission power of AHCR and DAHCR scheme 1 is less than that of AHR and DAHR, respectively. In addition, DAHCR scheme 2 further reduces the required transmission power of DAHCR scheme 1. On the other hand, DAHCR scheme 1 increases the complexity by 43% compared to DAHR. Besides, DAHCR scheme 2 increases the complexity by 1.97% compared to DAHCR scheme 1.

The active shape model (ASM) has been widely adopted by automated bone segmentation approaches for radiographic images. In radiographic images of the distal radius, multiple edges are often observed in the near vicinity of the bone, typically caused by the presence of thin soft tissue. The presence of multiple edges decreases the segmentation accuracy when segmenting the distal radius using ASM. In this paper, we propose an enhanced distal radius segmentation method that makes use of a modified version of ASM, reducing the number of segmentation errors. To mitigate segmentation errors, the proposed method emphasizes the presence of the bone edge and downplays the presence of a soft tissue edge by making use of Dual energy X-ray absorptiometry (DXA). To verify the effectiveness of the proposed segmentation method, experiments were performed with 30 distal radius patient images. For the images used, compared to ASM-based segmentation, the proposed method improves the segmentation accuracy with 47.4% (from 0.974 mm to 0.512 mm).

This paper proposes a novel image segmentation method based on Clausius entropy and adaptive Gaussian mixture model for detecting moving objects in a complex environment. The results suggest that the proposed method performs better than existing methods in extracting the foreground in various video sequences composed of multiple objects, lighting reflections, and background clutter.

We review our recent work on ultra-long-haul wavelength division multiplexed (WDM) transmission with high spectral efficiency (SE) employing tight pre-filtering and multi-symbol detection. We start the discussion with a theoretical evaluation of the SE limit of pre-filtered modulation in optical fiber communication systems. We show that pre-filtering induced symbol correlation generates a modulation with memory and thus, a higher SE limit than that of the original memory-less modulation. We also investigate the merits of utilizing the pre-filtering induced symbol correlation with multi-symbol detection to achieve high SE transmission. We demonstrate transoceanic WDM transmission of a pre-filtered polarization division multiplexed return-to-zero quaternary phased shift keying (PDM-RZ-QPSK) modulation format with multi-symbol detection, achieving 419% SE which is higher than the SE limit of the original memory-less PDM-RZ-QPSK format.