In LDMOS devices for high-voltage applications, there appears a notable fingerprint of current-voltage characteristics known as soft breakdown. Its mechanism is analyzed and modeled on LDMOS devices where a high resistive drift region exists. This analysis has revealed that the softness of breakdown, known as the expansion effect, withholding a run-away of current, is contributed by the flux of holes underneath the gate-overlap region originated by impact-ionization. The mechanism of the expansion effect is modeled and implemented into the compact model HiSIM_HV for circuit simulation. A good agreement between simulated characteristics and 2D-device simulation results is verified.

Without recourse to the Shannon-Nyquist sampling theorem, a novel information sampling (IS) concept is proposed for ultra-wideband (UWB) communications. To implement IS, a random pre-coding system architecture is designed and system performance is studied. Simulation results from one of UWB channel models show that the proposed system is effective to detect UWB signals with a low-sampling-rate analog-to-digital converter (ADC) at the receiver. Moreover, it can operate in a regime of heavy inter-symbol interference (ISI).

Variable-weight optical orthogonal codes (OOCs) were introduced by Yang for multi-media optical CDMA systems with multiple quality of service (QoS) requirements. Some works had been done on the existence of optimal (υ,W,1,Q)-OOCs for W ∈ {{3,4}, {3,5}, {4,5}}. In this paper, by using quadratic residues, seven new infinite classes of optimal (υ,{k,6},1,Q)-OOCs for k ∈ {3,4} are constructed.

This paper proposes Burst Error Resilient coding (BRC) technology in mobile broadcasting network. The proposed method utilizes Scalable Video Coding (SVC) and Forward Error Correction (FEC) to overcome service outage due to burst loss in mobile network. The performance evaluation is performed by comparing PSNR of SVC and the proposed method under MBSFN simulation channel. The simulation result shows PSNR of SVC equal error protection (EEP), unequal error protection (UEP) and proposed BRC using Raptor FEC code.

A method obtaining a monochrome image which can rebuild colors is proposed. In this method, colors in an input image are quantized under a lightness constraint and a palette, which represents relationship between quantized colors and gray-levels, is generated. Using the palette, an output monochrome image is obtained. Experiments show that the proposed method obtains good monochrome and rebuilt color images.

This paper introduces balanced switching schemes to compensate linear and quadratic gradient errors, in the unary current source array of a current-steering digital-to-analog converter (DAC). A novel algorithm is proposed to avoid the accumulation of gradient errors, yielding much less integral nonlinearities (INLs) than conventional switching schemes. Switching scheme examples with different number of current cells are also exhibited in this paper, including symmetric arrays and non-symmetric arrays in round and square outlines. (a) For symmetric arrays where each cell is divided into two parallel concentric ones, the simulated INL of the proposed round/square switching scheme is less than 25%/40% of conventional switching schemes, respectively. Such improvement is achieved by the cancelation of linear errors and the reduction of accumulated quadratic errors to near the absolute lower bound, using the proposed balanced algorithm. (b) For non-symmetric arrays, i.e. arrays where cells are not divided into parallel ones, linear errors cannot be canceled, and the accumulated INL varies with different quadratic error distribution centers. In this case, the proposed algorithm strictly controls the accumulation of quadratic gradient errors, and different from the algorithm in symmetric arrays, linear errors are also strictly controlled in two orthogonal directions simultaneously. Therefore, the INLs of the proposed non-symmetric switching schemes are less than 64% of conventional switching schemes.

This letter addresses antenna ordering to improve the performance of the MIMO detectors in [4], where two low complexity MIMO detectors have been proposed based on either fully-connected or ring type pair-wise Markov random field (MRF). The former was shown to be better than the latter, while being more complex. The objective of this letter is to make the performance of the detector based on ring-type MRF (with complexity of O(2M 22m)) close to or better than that of fully-connected MRF (with complexity of O(M (M-1)22m)), by applying appropriate antenna ordering. The simulation results validate the proposed antenna ordering methods.

To acquire a second language, one must develop an ear and tongue for the correct stress and intonation patterns of that language. In English language teaching, there is an effective method called Jazz Chants for working on the sound system. In this paper, we propose a method for predicting stressed words, which play a crucial role in Jazz Chants. The proposed method is specially designed for stress prediction in Jazz chants. It exploits several sources of information including words, POSs, sentence types, and the constraint on the number of stressed words in a chant text. Experiments show that the proposed method achieves an F-measure of 0.939 and outperforms the other methods implemented for comparison. The proposed method is expected to be useful in supporting non-native teachers of English when they teach chants to students and create chant texts with stress marks from arbitrary texts.

NICT has developed a test model of an optically controlled beam-forming network (OBF) for a future multiple-beam antenna. The OBF test model consists of an electro-optic converter unit, an OBF unit, and an optoelectronic converter unit. A Ka-band OBF test model was manufactured to demonstrate the OBF. Radiation patterns obtained from the measured OBF data confirmed agreement between the expected and calculated results. Communication tests of the bit error rate (BER) for the digital communication link were performed. The results confirmed the OBF had no serious degradation below 1 dB of Eb/N0 on BER performance at 110-8.

Microblogs are a rising social network with distinguishing features such as simplicity and convenience and has already attracted a large number of users and triggered massive information explosion concerning individuals' own statuses and opinions. While sentiment analysis of the messages in microblogs is of great value, most of present studies are on English microblogs and few are on Chinese microblogs. Compared to English, Chinese has its unique expression style, such as no spaces or other word delimiters. Furthermore, Chinese short text also has its own properties. Thus we are inspired to explore effective features for sentiment classification of Chinese short text. In this paper, we propose to study user-related sentiment classification of Chinese microblogs in terms of the statistical and semantic characteristics, and deisgn the corresponding features: ratio of positive words and negative words (PNR), position feature (POS), collocation of verbs (COL), auxiliary words (AU). Then we employ an SVM-based method to classify the sentiment. Experiments show that the features we design is effective in recognizing the sentiment of messages in microblogs.

Scalable video coding with different modulation and coding schemes (MCSs) applied to different video layers is very appropriate for wireless multicast services because it can provide different video quality to different users according to their channel conditions, and a promising solution to handle packet losses induced by fading wireless channels is the use of layered hybrid FEC/ARQ scheme according to light-weight feedback messages from users about how many packets they have received. It is important to choose an appropriate MCS for each layer, decide how many parity packets in one layer should be transmitted, and determine the resources allocated to multiple video sessions to apply scalable video coding to wireless multicast streaming. We prove that such resource allocation problem is NP-hard and propose an approximate optimal algorithm with a polynomial run time. The algorithm can get the optimal transmission configuration to maximize the expected utility for all users where the utility can be a generic non-negative, non-decreasing function of the received rate. The results from simulations revealed that our algorithm offer significant improvements to video quality over a nave algorithm, an optimal algorithm without feedback from users, and an algorithm with feedback from designated users, especially in scenarios with multiple video sessions and limited radio resources.

This paper presents a multi-band WCDMA receiver consisting of a multi-band low noise amplifier (LNA), a multi-band mixer and an inter-stage tunable notch filter. The notch filter is used to suppress Tx leakage, and 0.8–1.5 GHz (66%) of tuning range is achieved. The receiver achieves 33 and 30 dB conversion gain, 6.4 and 8 dB NF, 50 and 35.5 dBm IIP2, and -6 and -4.7 dBm IIP3 at 0.8 and 1.5 GHz, respectively. The power consumption is 121 mW from a 1.8-V power supply. The receiver is implemented in a 0.18-µm CMOS process.

In the framework of the modernization plan of COMPASS system, the existing COMPASS signals should be transmitted along with the modernized signals to maintain backward compatibility. In this paper, an efficient multiplexing scheme based on the optimal aligning method for combining COMPASS Phase II B3 and Phase III B3 signals is proposed, which offers significantly higher efficiency than Interplex and Generalized Majority Voting (GMV) multiplexing methods. The proposed scheme can provide potential opportunities for COMPASS system and other global navigation satellite systems (GNSS) modernization and construction plans.

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.

This paper proposes a video-quality estimation method based on a no-reference model for realtime quality monitoring in video-streaming services. The proposed method analyzes both bitstream information and decoded pixel information to estimate video-quality degradation by transmission errors. Video quality in terms of a mean squared error (MSE) between degraded video frames and error-free video frames is estimated on the basis of the number of impairment macroblocks in which the quality degradation has not been possible to be concealed. Error-concealment effectiveness is evaluated using motion information and luminance discontinuity at the boundaries of impairment regions. Simulation results show a high correlation (correlation coefficients of 0.93) between the actual MSE and the number of macroblocks in which error concealment has not been effective. These results show that the proposed method works well in reatime quality monitoring for video-streaming services.

Shisen-Sho is a tile-based one-player game. The instance is a set of 136 tiles embedded on 817 rectangular grids. Two tiles can be removed if they are labeled by the same number and if they are adjacent or can be connected with at most three orthogonal line segments. Here, line segments must not cross tiles. The aim of the game is to remove all of the 136 tiles. In this paper, we consider the generalized version of Shisen-Sho, which uses an arbitrary number of tiles embedded on rectangular grids. It is shown that deciding whether the player can remove all of the tiles is NP-complete.

Timing asynchronism strongly degrades the performance of analog network coded (ANC) bi-directional transmission. This letter investigates receiver design for asynchronous broadband bi-directional transmission over frequency selective fading channels. Based on time domain oversampling, we propose fractionally spaced frequency domain minimum mean square error (MMSE) equalizers for bi-directional ANC based on orthogonal frequency division multiplexing (OFDM) and cyclic prefixed single carrier (CP-SC) radio access. Simulation results show that the proposed fractionally spaced equalizer (FSE) can eliminate the negative effect of timing misalignment in bi-directional transmissions.

In H.264/AVC intra frame coding, the rate-distortion optimization (RDO) is employed to select the optimal coding mode to achieve the minimum rate-distortion cost. Due to a large number of combinations of coding modes, the computational burden of Rate distortion optimization (RDO) becomes extremely high in intra prediction. In this paper, we proposed an efficient selective intra block size decision (SIB) that selects the appropriate block size for intra prediction, further proposed fast intra prediction algorithm reduces a number of modes required for RDO that significantly reduces the encoder complexity. Experimental results show that the proposed fast mode decision algorithm reduces the encoding time by up to 68% with negligible video quality degradation.

Previous inter-domain fast authentication schemes only realize the authentication of user identity. We propose a trusted inter-domain fast authentication scheme based on the split mechanism network. The proposed scheme can realize proof of identity and integrity verification of the platform as well as proof of the user identity. In our scheme, when the mobile terminal moves to a new domain, the visited domain directly authenticates the mobile terminal using the ticket issued by the home domain rather than authenticating it through its home domain. We demonstrate that the proposed scheme is highly effective and more secure than contemporary inter-domain fast authentication schemes.

Optical orthogonal codes (OOCs) were introduced by Salehi, as signature sequences to facilitate multiple access in optical fibre networks. The existence of optimal (υ,3,1)-OOCs had been solved completely. Although there are some partial results, the existence of optimal (υ, 4, 1)-OOCs is far from settled. In this letter, three general constructions for (υ, 4, 1)-OOCs via perfect difference families are presented, new infinite classes of (υ, 4, 1)-OOCs are then obtained.