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.     

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.     

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.     

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.     

Multi-source Local Color Transfer Based on Texture Similarity

In order to realize automatic region matching between source and target images, a multi-source local color transfer algorithm based on texture similarity is proposed. The source and target images are segmented into a set of regions using an image segmentation algorithm. It computes the texture features of each region through the gray level co-occurrence matrix and then constructs corresponding texture feature vectors. The authors measure the relevance between the target and source regions by computing the Euclidean distance between corresponding tex- ture feature vectors. The source region having the largest relevance with the target region is selected as the transfer source. Complete the color transfer by performing color space transformation and linear conversion on color values. Experimental results concerning on multi-source local color transfer and gray image colorization verify the validity of the proposed algorithm.     

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.     

Research on Unified Description and Extension of Combination Rules of Evidence Based on Random Set Theory

Dempster＇s combination rule has been a widely used mechanism for combining multisource information. However, it has restrictive application conditions, which sometimes are ignored or hardly satisfied in some cases, so gives counterintuitive combination results. In order to remove its inherent limitations, the modified rules have been found in the existing literature, but the different rules have been only applied to the different cases. So it is very necessary to search their common foundation so as to reveal the essence of evidence combination. Therefore, on the basis of random set theory, an unified formulation of combination rules is presented, which can describe most classical combination rules besides Dempster＇s rule, and what＇s more, which attempt to provide an original ideas for constructing more applicable and effective combination rules. Finally, by use of this formulation, a new combination rule is constructed for overcoming a class of counterintuitive phenomena pointed out by Lotfi Zadeh.     

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.     

Does Amplify-and-Forward Cooperative Relay Improve OFDM/OFDMA Ergodic Capacity？

The ergodic information rate for Orthogonal Frequency-Division Multiplexing / Orthogonal Frequency-Division Multiple Access with amplify-and-forward （AF） relaying systems in the presence of frequency offsets is evaluated. Unlike previous work, per-subcarrier adaptive power allocation is performed on each relay to optimize the system ergodic information rate. For a given frequency offset and total number of relays M, the AF ergodic information rate is proven to be a monotonically increasing function of α （the ratio of the power allocated to the source node and the total transmit power）, implying that the maximum ergodic information rate can be obtained at α=1 （i.e., there is no cooperative relay）. Furthermore, the proof of ＂cooperative relays cannot improve the AF ergodic information rate in a quasi-static wireless channel＂ is also provided in this letter.     

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.     

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.     

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.     

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.     

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.     

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.     

Lossless Digital Watermarking Scheme for Image Maps

A lossless digital watermarking scheme,which was zero- perturbation on the content and graphics for the digital image maps,is proposed.During the simulation,the scheme has been utilized to model the copyright protection program as a commerce application.Compared to the traditional digital watermarking schemes,our scheme operates in redundancy areas of maps and is scalable to topology changes.Experimental results show that,with respect to the geometric attacks and image transformed,the performance of our scheme is better than the classical algorithms based space or frequency domain with much lower complexity..     

Stability Analysis of Information Spreading on SNS Based on Refined SEIR Model

Investigating the stability of information spreading over SNS helps to understand the principles inherent in the spreading behavior. This paper explores the mechanisms of information spreading including stifling mechanism, latent mechanism and forgetting mechanism, establishes a refined SEIR model, and builds the corresponding mean-field equations. The methods of the differential dynamics and the next generation matrix are used to calculate the equilibriums and the basic reproductive number, and the asymptotical stability of the network equilibriums are proved theoretically. Simulation experiments are carried out to analyze the effect of the spreading mechanisms on the information spreading process and the results support our conclusions.