Fast and Robust DOA Estimation Method Using Searching Space Pre-estimation

An improved MUSIC localization algorithm is proposed in this paper in order to locate a sound source in reverberant and directional noise scenario, with comparatively low computational complexity. Based on Time delay of arrival （TDOA） estimation, a candidate searching space is first predetermined and then Beamspace MUSIC combined with Spatial smoothing （BMUSIC-SS） algorithm is applied in this space to find the Direction of arrival （DOA） of the desired source. This two-step method not only reduces the number of calculations by avoiding the exhaustive search, but also improves the localization performance in coherent noise environment due to the fact that the spaces including directional noises are partially removed. Besides, based on the localization system we developed, the DOA parameters are separated to reduce a two-dimension search into a couple of one dimensional ones that further cuts down the computational load. The computer simulations and practical experiments demonstrate the robustness and efficiency of the proposed method.     

Mining User Interest in Microblogs with a User-Topic Model

Microblogs have become an important platform for people to publish, transform information and acquire knowledge. This paper focuses on the problem of discovering user interest in microblogs. In this paper, we propose a topic mining model based on Latent Dirichlet Allocation （LDA） named user-topic model. For each user, the interests are divided into two parts by different ways to generate the microblogs： original interest and retweet interest. We represent a Gibbs sampling implementation for inference the parameters of our model, and discover not only user＇s original interest, but also retweet interest. Then we combine original interest and retweet interest to compute interest words for users. Experiments on a dataset of Sina microblogs demonstrate that our model is able to discover user interest effectively and outperforms existing topic models in this task. And we find that original interest and retweet interest are similar and the topics of interest contain user labels. The interest words discovered by our model reflect user labels, but range is much broader.     

Adaptive Method of Velocity Control for Cardiac CT

The image for cardiac CT is blurred because the heart is in motion. Currently, fixed scan velocity for cardiac CT is used and approximate projection can only be achieved due to the non-synchronism between the heartbeat and scan velocity. In order to achieve ideal projection, the control method for selectable scan velocity is proposed according to heartbeat. The velocity varies with the heart beat, temporal resolution and control parameters to achieve a desirable temporal resolution in nonperiodic heartbeat. The selectable scan velocity can provide ideal projection with uniform distribution and the same phases. The simulation result shows that the variable velocity method outperforms the current fixed velocity method.     

A Fast Algorithm for Near Field Radiated by Aperture Antennas

A fast algorithm in frequency and time domain is presented for near field radiated by aperture antennas. The convolution formulation is earlier developed to relate the near field to the equivalent magnetic current sources on the aperture in frequency domain, which accelerates the near field＇s calculation via FFT, and Fourier transform pairs have been found on the basis of Plane wave spectrum （PWS） theory and convolution theorem. The algorithm in time domain can be obtained based on the method of frequency domain, which has been proved by the rigorous Electromagnetic theory associated with Fourier transform theory. Numerical results are presented for two antennas to verify the fast algorithm.     

Multi-Agent Immune Memory Clone Based Multicast Routing

Ab-Ab affinity which is a type of distance between antibodies is an important factor for an immune algorithm to maintain population diversity. However, it is a hard work to define an appropriate distance for some practical applications like the QoS multicast routing problem. To remedy this, an artificial immune algorithm based on new model is proposed for the QoS multicast routing problem. In this work, antibodies are fixed onto a latticelike environment and new immune operators and memory mechanism are also designed. Experimental results indicate that the proposed approach maintains a good diversity and achieves superior performs.     

A Feedback Correction De-noising Algorithm Based on the Wavelet Coefficients

The localization of satellite interference sources under the condition of low SNR has been a hot research topic at current, where the signal de-noising is important in the following positioning work. With the help of the wavelet analysis theory, this paper proposes a denoising algorithm based on the wavelet coefficients in low SNR. After correcting and reconstructing the signal by the correction coefficients, we could obtain the SNR and Root mean square error （RMSE）, and then we could correct the signal for the second time. The simulation results show that this de-noising algorithm can effectively remove the noise of the signal in low SNR, which would have a good effect on the estimation of time delay parameter in the localization of satellite interference sources.     

Golay Sequence Based Time-Domain Compensation ot Frequency-Dependent I/Q Imbalance

A time-domain frequency- dependent I/Q imbalance compensation scheme based on Golay complementary sequence for receiver is presented. By utilizing property of Golay sequence, the signal and its conjugate interference （image interference） in preamble are separated by correlation and used to estimate I/Q imbalance parameters. After that, a Least Square （LS） estimation of compensation filter is obtained and adopted in the compensation structure. Two applications of the presented algorithm are discussed： we could either estimate the channel along with I/Q imbalance or estimate the imbalance parameter only to maintain a lower cost. Both applications are testified by simulation. The results show that the image interference is significantly suppressed even in poor SNR condition, and the computation cost of the algorithms is low.     

Utilizing Sub-topic Units for Patent Prior-Art Search

One of the defining challenges in patent prior-art search is the problem of representing a long, technical document as a query. Previously work on this problem has concentrated on single query representations of the patent application. In the following paper, we describe an approach which uses multiple query representations generated from semantically coherent passages extracted from patent documents. We validate our technique in an experiment using the CLEF-IP 2011 patent search collection. Our system achieves statistically significant improvements over various state-of-art query generation techniques.     

The Bipolar Field-Effect Transistor:XIII. Physical Realizations of the Transistor and Circuits (One-Two-MOS-Gates on Thin-Thick Pure-Impure Base)

This paper reports the physical realization of the Bipolar Field-Effect Transistor （BiFET） and its onetransistor basic building block circuits. Examples are given for the one and two MOS gates on thin and thick, pure and impure base, with electron and hole contacts, and the corresponding theoretical current-voltage characteristics previously computed by us, without generation-recombination-trapping-tunneling of electrons and holes. These examples include the one-MOS-gate on semi-infinite thick impure base transistor （the bulk transistor） and the impurethin-base Silicon-on-Insulator （SOI） transistor and the two-MOS-gates on thin base transistors （the FinFET and the Thin Film Transistor TFF）. Figures are given with the cross-section views containing the electron and hole concentration and current density distributions and trajectories and the corresponding DC current-voltage characteristics.     

On the Cycle Structure of Some Nonlinear Feedback Shift Registers

In this paper, we partly determine the cycle structure of two types of Nonlinear feedback shift registers （NFSRs）. Based on these results, the cycle structure of a class of NFSRs with symmetric feedback functions can be completely characterized. Furthermore, an alternative proof of Kjeldsen＇s results is presented. Compared with the original proof based on abstract algebra theory, ours is straightforward and easy to understand.     

SDN-Based Data Offioading for 5G Mobile Networks

The rapid growth of 3G/4G enabled devices such as smartphones and tablets in large numbers has created increased demand formobile data services.Wi-Fi offloading helps satisfy the requirements of data-rich applications and terminals with improved multi-media.Wi-Fi is an essential approach to alleviating mobile data traffic load on a cellular network because it provides extra capaci-ty and improves overall performance.In this paper,we propose an integrated LTE/Wi-Fi architecture with software-defined net-working(SDN)abstraction in mobile backhaul and enhanced components that facilitate the move towards next-generation 5G mo-bile networks.Our proposed architecture enables programmable offloading policies that take into account real-time network condi-tions as well as the status of devices and applications.This mechanism improves overall network performance by deriving real-time policies and steering traffic between cellular and Wi-Fi networks more efficiently.     

The Data Age of Mobile Cellular Network in Germany and China： Policies,Technologies and Markets （Part I）

The UMTS auction in 2000 brought approximately 100 billion DM （Deutsche Mark） for the German National Treasury. T-Mobile （D1-Netz）, Vodafone （D2-Netz）, E-Plus （E1-Netz） and 02 （E2-Netz） have gradually evolved from GSM to full-fledged UMTS operators over the past years. The conglomerate of China Telecom was split twice. China acceded to WTO and promulgated the FITE Provisions. MIIT （Ministry of Industry and Information Technology） became the regulator and China Netcom was incorporated into China Unicorn in 2008. Most recently the layout of 3G future has been reconfirmed by MIIT. Voice service has remained the main source of income in both countries and operators have continued to focus on voice quality and network availability in their respective 2G networks. Because value-added and higher-speed data applications have been gaining market attention, 2.5G and 3G infrastructure has increasingly become the focal network strategy for the operators since the beginning of the new century. Germany has rolled out WCDMA/UMTS services on a large scale in the consumer market, while China has adopted all three 3G standards （TD-SCDMA, WCDMA/UMTS, CDMA2000）, which shall gradually capture a wider 3G subscriber base. The summary shows that the development of the cellular technology and market in Germany and China can be discussed in three distinct historical periods. The conclusion suggests that the case of the cellular technology appears to be consistent with and applicable to a number of arguments widely disputed in economics and management related to technology and innovation, such as dominant design, technology waves/ S-Curve, disruptive technologies, Technology Adoption Life Cycle.     

Software Radio——Software Radio： A Review of Design Considerations and Digital Hardware Choices

This paper reviews the requirements for Software Defined Radio （SDR） systems for high-speed wireless applications and compares how well the different technology choices available- from ASICs, FPGAs to digital signal processors （DSPs） and general purpose processors （GPPs） - meet them.     

Large-signal characterizations of DDR IMPATT devices based on group Ⅲ-Ⅴ semiconductors at millimeter-wave and terahertz frequencies

Large-signal （L-S） characterizations of double-drift region （DDR） impact avalanche transit time （IM- PATT） devices based on group III-V semiconductors such as wurtzite （Wz） GaN, GaAs and InP have been carried out at both millimeter-wave （mm-wave） and terahertz （THz） frequency bands. A L-S simulation technique based on a non-sinusoidal voltage excitation （NSVE） model developed by the authors has been used to obtain the high frequency properties of the above mentioned devices. The effect of band-to-band tunneling on the L-S properties of the device at different mm-wave and THz frequencies are also investigated. Similar studies are also carried out for DDR IMPATTs based on the most popular semiconductor material, i.e. Si, for the sake of comparison. A compara- tive study of the devices based on conventional semiconductor materials （i.e. GaAs, InP and Si） with those based on Wz-GaN shows significantly better performance capabilities of the latter at both mm-wave and THz frequencies.     

Hybrid Weighted l1-Total Variation Constrained Reconstruction for MR Image

Compressed sensing based Magnetic resonance （MR） image reconstruction can be done by minimizing the sum of least square data fitting item, the Total variation （TV） and ll norm regularizations. In this paper, inspired by the conventional constrained reconstruction model, we propose a hybrid weighted l1-TV minimization method to reconstruct MR image. We introduce the iterative mechanism to update the weights for l1 and TV norms adaptively. The weights vary at each element of the image matrix according to the presented weights selection strategy. Experiments on Shepp-Logan phantom and practical MR. images demonstrate the proposed method can preserve image details and obtain improved reconstruction quality compared to the traditional CS-MRI method and other weighted methods.     

EEFA： Energy Efficiency Frame Aggregation Scheduling Algorithm for IEEE 802.11n Wireless Network

Packet size is restricted due to the error-prone wireless channel which drops the network energy utilization. Furthermore, the frequent packet retransmissions also lead to energy waste. In order to improve the energy efficiency of wireless networks and save the energy of wireless devices, EEFA （Energy Efficiency Frame Aggregation）, a frame aggregation based energy-efficient scheduling algorithm for IEEE 802.11n wireless network, is proposed. EEFA changes the size of aggregated frame dynamically according to the frame error rate, so as to ensure the data transmission and retransmissions completed during the TXOP and reduce energy consumption of channel contention. NS2 simulation results show that EEFA algorithm achieves better performance than the original frame-aggregation algorithm.     

Weighted Multi-source TrAdaBoost

In order to take full advantage of valuable information from all source domains and to avoid negative transfer resulted from irrelevant information, a kind of weighted multi-source TrAdaBoost algorithm is proposed. At flrst some weak classifiers are respectively trained based on training sample sets constituted by both each source domain and the target domain. Then we assign a weight to each weak classifier according to its error on the target training set. In the third step, a candidate classifier is obtained based on the weighted sum of all weak classifiers. In the fourth step, sample weights of the source and target domains are updated according to the error of the candidate classifier on corresponding domains. At last, all weak classifiers are retrained based on the training samples with new updated weights. The above steps repeated until the number of maximum iterations is reached. Experimental results on bimonthly datasets show that, compared with TrAdaBoost and multi-source TrAdaBoost, the proposed algorithm has higher classification accuracy.     

应用于生物医疗的0.6-V 8.3-ENOB 异步时序逐次逼近型模数转换器

A microwatt asynchronous successive approximation register （SAR） analog-to-digital converter （ADC） is presented. The supply voltage of the SAR ADC is decreased to 0.6 V to fit the low voltage and low power require- ments of biomedical systems. The tail capacitor of the DAC array is reused for least significant bit conversion to decrease the total DAC capacitance thus reducing the power. Asynchronous control logic avoids the high frequency clock generator and further reduces the power consumption. The prototype ADC is fabricated with a standard 0.18 μm CMOS technology. Experimental results show that it achieves an ENOB of 8.3 bit at a 300-kS/s sampling rate. Very low power consumption of 3.04 μW is achieved, resulting in a figure of merit of 32 fJ/conv.-step.     

Design of a 16 gray scales 320×240 pixels OLED-on-silicon driving circuit

A 320×240 pixel organic-light-emitfing-diode-on-silicon （OLEDoS） driving circuit is implemented using the standard 0.5μm CMOS process of CSMC. It gives 16 gray scales with integrated 4 bit D/A converters. A three- transistor voltage-programmed OLED pixel driver is proposed, which can realize the very small current driving required for the OLEDoS microdisplay. Both the D/A converter and the pixel driver are implemented with pMOS devices. The pass-transistor and capacitance in the OLED pixel driver can be used to sample the output of the D/A converter. An additional pMOS is added to OLED pixel driver, which is used to control the D/A converter operating only when one row is on. This can reduce the circuit＇s power consumption. This driving circuit can work properly in a frame frequency of 50 Hz, and the final layout of this circuit is given. The pixel area is 28.4 × 28.4μm^2 and the display area is 10.7 × 8.0 mm^2 （the diagonal is about 13 mm）. The measured pixel gray scale voltage shows that the function of the driver circuit is correct, and the power consumption of the chip is about 350 mW.