MPEG-2到MPEG-4视频转编码中的快速运动矢量重估算法

本文讨论了MPEG-2到MPEG-4视频转编码问题,提出了两种快速运动矢量重估算法,分别基于空域和时域。我们的算法利用已有运动信息和DCT变换的直流系数进行运动估计,可明显减少运算量,提高编码速度,并获得了与全搜索算法接近的图像质量,可满足网络视频传输的实时要求。

基于被动时间反转-自编码器的水声通信信号调制识别方法

海洋环境中存在的多径效应会影响水声通信信号的特征,降低调制识别准确率.为了减小多径效应对信号调制识别造成的干扰,本文提出了一种基于被动时间反转-自编码器的信号增强方法.利用水声通信信号中常见的同步信号作为探测信号,实现无外加信号的被动时间反转以及功率谱和平方谱两种频域特征的增强,并设计了卷积神经网络进行调制识别.网络模型经过Bellhop仿真水声信道和少量非测试环境的实测数据进行训练后,在3种与训练环境不同的实际水声信道下测试,所有调制信号识别准确率均高于80%,6种调制信号的平均识别准确率与已有文献中的方法相比至少提高了20个百分点.

基于时分复用技术的低功耗数据总线FV-BI自适应编码

对频率值（frequent value,FV）编码技术进行了改进,并结合总线反转（bus invert,BI）编码技术的优点提出了FV-BI自适应总线编码,利用时分复用技术解决了多套数据总线混合编码问题和需要两根额外数据线问题。基于基准测试程序、图片及音视频和随机数的测试,结果表明提出的FV-BI自适应总线编码技术能降低22%-53%的开关活动,相比单独FV编码和BI编码技术开关活动降低2-4倍。利用Matlab软件和PrimePower软件,在0.18μm工艺下针对不同互连线长度进行行为级和sign-off级功耗估计,结果表明在接近10mm互连线长度下,FV-BI自适应编码技术能有效降低芯片功耗。最后完成了FV、BI和FV-BI自适应编码技术在现场可编程门阵列（field programmable gate array,FPGA）的实现,利用Xpower软件分析其功耗,并进行FPGA板级测试,结果也证明了FV-BI编码技术降低功耗的有效性。

空间-时间关联的中介共同表征结构:来自反转STEARC效应的证据

通过3个双任务实验(诱导任务和特征任务)探讨空间-时间联合编码(STEARC)效应的加工机制。实验1采用时间信息作为诱导任务材料,实验2采用空间信息作为诱导任务材料,在特征任务中都发现映射不一致组被试(看到过去/左侧刺激时按右键反应,看到未来/右侧刺激时按左键反应)出现反转STEARC效应,映射一致组被试表现出常规的STEARC效应,表明从时间信息加工到空间反应过程符合中介共同表征结构。实验3分离两种任务的反应方式(手动和眼动),发现不一致映射规则下,被试仍然表现出常规的STEARC效应,表明这种中介共同表征结构存在特定联结效应,即在不同反应器中出现时间和空间相互独立的表征结构。总体而言,研究支持空间-时间关联符合中介共同表征结构,并且这种关联中存在反应器特定联结效应。

一种新的基于子空间的盲信道估计方法

提出了一种新的基于子空间的盲信道估计方法。该方法利用时序反转空时分组编码,运用"虚拟接收天线"的方法进行盲信道估计,在一定程度上克服了传统的基于子空间的信道估计算法对MIMO系统中输入输出天线数目的要求限制。仿真结果证明了此方法有较好的信道估计性能。

在CASS5.0中调用和处理JX4矢量测图数据的方法

文章介绍在CASS5.0中,通过调用和处理JX4数字摄影测量工作站的矢量测图数据,使数据完全成为CASS5.0标准的数字化地形图的方法。

PLC控制异步电机变频调速传送带精确定位系统的设计

三相异步电机变频调速可以获得理想的调速性能,当进一步采用PLC、D/A转换器、变频器、三相异步电机及旋转编码器组成闭环控制系统将大大提高控制性能,可进行PID控制,具有远程通信功能,闭环系统又能提高位置控制的定位精度,本文介绍了采用PLC来实现传送带精确定位闭环控制的方法。

CMA盲均衡在MIMO MC DS-CDMA系统中的应用研究

本文首先建立了采用TR-STBC发送分集的MIMO MC DS-CDMA系统模型,然后在此基础上,研究了SDCMA盲均衡在该系统中的应用,最后进行了仿真和分析。结论是对采用TR-STBC方案的MIMO MC DS-CDMA系统进行常模盲均衡,算法简单,较易实现,但当多址干扰较大时,仅采用此均衡方法不能较好地改善系统性能,还需要进一步采用其他方法来减小或消除多址干扰。

Design and control of integrated pneumatic dexterous robot finger

Based on flexible pneumatic actuator(FPA),bending joint and side-sway joint,a new kind of pneumatic dexterous robot finger was developed.The finger is equipped with one five-component force sensor and four contactless magnetic rotary encoders.Mechanical parts and FPAs are integrated,which reduces the overall size of the finger.Driven by FPA directly,the joint output torque is more accurate and the friction and vibration can be effectively reduced.An improved adaptive genetic algorithm(IAGA) was adopted to solve the inverse kinematics problem of the redundant finger.The statics of the finger was analyzed and the relation between fingertip force and joint torque was built.Finally,the finger force/position control principle was introduced.Tracking experiments of fingertip force/position were carried out.The experimental results show that the fingertip position tracking error is within ±1 mm and the fingertip force tracking error is within ±0.4 N.It is also concluded from the theoretical and experimental results that the finger can be controlled and it has a good application prospect.

Liposome transfected to plasmid-encoding endostatin gene combined with radiotherapy inhibits liver cancer growth in nude mice

AIM： To evaluate whether intratumoral injection of liposome-endostatin complexes could enhance the antitumor efficacy of radiation theapy in human liver cardnoma （BEL7402） model.METHODS： Recombinant plasmid pcDNA3.End was transfected into human liver carcinoma cell line （BEL7402） with lipofectamine to produce conditioned medium. Then BEL7402 cells and human umbilical vein endothelial cells （HUVECs） were treated with the conditioned medium. Cell cycle and apoptosis were analyzed by flow cytometer and endothelial cell proliferation rates were determined by MTT assay. The antitumor efficacy of endostatin gene combined with ionizing radiation in mouse xenograft liver tumor was observed.RESULTS： Endostatin significantly suppressed the S phase fraction and increased the apoptotic index in HUVECs. In contrast, endostatin treatment had no effect on BEL7402 cell apoptosis （2.1±0.3% vs 8.9±1.3%, t= 8.83, P= 0.009〈0.01） or cell cycle distribution （17.2±2.3% vs 9.8±1.2%, t = 4.94,P = 0.016〈0.05）. The MTT assay showed that endostatin significantly inhibited the proliferation of HUVECs by 46.4%. The combination of local endostatin gene therapy with radiation therapy significantly inhibited the growth of human liver carcinoma BEL7402 xenografts, the inhibition rate of tumor size was 69.8% on d 28 compared to the untreated group. The tumor volume in the pcDNA3.End combined with radiation therapy group （249±83 mm^3） was significantly different from that in the untreated group （823±148 mm^3, t= 5.86, P= 0.009〈0.01） or in the pcDNA3 group （717±94 mm^3, t= 6.46, P= 0.003〈0.01）. Endostatin or the radiation alone also inhibited the growth of liver tumor in vivo, but their inhibition effects were weaker than those of endostatin combined with radiation, the inhibition rates on d 28 were 44.7% and 40.1%, respectively.CONCLUSION： Endostatin not only significantly suppresses tumor growth but also enhances the antitumor efficacy of radiation therapy in human carcinoma xenograft.

Cooperative diversity based on rotation code

In order to obtain coding gain along with diversity gain,rotation code was applied to cooperative diversity employing decoded-and-forward cooperative protocol.Different from the same two symbols transmitted in conventional repetition-coded scheme,two different symbols were transmitted separately in two successive timeslots in the proposed rotation-coded cooperative diversity.In this way,constellation spread in the available two-dimensional signal space rather than on a single-dimensional line in repetition-coded scheme,which was supposed to be responsible for the additional coding gain.Under the proposed cooperative transmission model,upper bounds for the symbol-error-rate(SER)of cooperative diversity based on repetition code and rotation code were derived respectively.Both analytical and simulated results show that cooperative diversity based on rotation code can obtain an improved coding gain(by about 2 dB)than repetition-coded scheme without the expense of power or bandwidth.

Network Coding-based Reliable Broadcast Transmission in Wireless Networks

Recently, network coding has been applied to the loss recovery of reliable broadcast transmission in wireless networks. Since it was proved that fi nding the optimal set of lost packets for XOR-ing is a complex NP-complete problem, the available time-based retransmission scheme and its enhanced retransmission scheme have exponential computational complexity and thus are not scalable to large networks. In this paper, we present an efficient heuristic scheme based on hypergraph coloring and also its enhanced heuristic scheme to improve the transmission efficiency. Basically, our proposed schemes fi rst create a hypergraph according to the packet-loss matrix. Then our schemes solve the problem of generating XORed packets by coloring the edges of hypergraph. Extensive simulation results demonstrate that, the heuristic scheme based on hypergraph coloring and its enhanced scheme can achieve almost the same transmission efficiency as the available ones, but have much lower computational complexity, which is very important for the wireless devices without high computation capacity.

Length of the ORF, position of the first AUG and the Kozak motif are important factors in potential dual-coding transcripts

A single mammalian transcript normally encodes one protein, but the transcript of GNAS （G-protein u-subunit） contains two reading frames and produces two structurally unrelated proteins, XLas and ALEX. No other confirmed GNAS-Iike dual-coding transcripts have been reported to date, even though many such candidate genes have been predicted by bioinformatics analysis. In this study, we constructed a series of vectors to test how two protein products were translated from a single transcript in vitro. The length of the ORF （open reading frame）, position of the first AUG and the Kozak motif were found to be important factors. These factors, as well as 55-bp NMD （nonsense-mediated mRNA decay） rule, were used in a bioinformatics search for candidate dual-coding transcripts. A total of 1307, 750 and 474 two-ORF-containing transcripts were found in human, mouse and rat, respectively, of which 170, 89 and 70, respectively, were found to be potential dual-coding transcripts. Most transcripts showed low conservation among species. Interestingly, dual-coding transcripts were significantly enriched for transcripts from the zinc-finger protein family, which are usually DNA-binding proteins involved in regulation of the transcription process.

Suppression of cell growth and invasion by miR-205 in breast cancer

MicroRNAs （miRNAs） are endogenous, small, non-coding RNAs, which are capable of silencing gene expression at the post-transcriptional level. In this study, we report that miR-205 is significantly underexpressed in breast tumor compared to the matched normal breast tissue. Similarly, breast cancer cell lines, including MCF-7 and MDA-MB- 231, express a lower level miR-205 than the non-malignant MCF-10A cells. Of interest, ectopic expression of miR-205 significantly inhibits cell proliferation and anchorage independent growth, as well as cell invasion. Furthermore, miR- 205 was shown to suppress lung metastasis in an animal model. Finally, western blot combined with the luciferase reporter assays demonstrate that ErbB3 and vascular endothelial growth factor A （VEGF-A） are direct targets for miR-205, and this miR-205-mediated suppression is likely through the direct interaction with the putative miR-205 binding site in the 3＇-untranslated region （3＇-UTR） of ErbB3 and VEGF-A. Together, these results suggest that miR- 205 is a tumor suppressor in breast cancer.

PRACTICAL ALGORITHMS FOR TORNADO CODES

Tornado codes have been used in the error control of data transmission in IP network. The efficiency of this erasure codes is critically affected by the short cycles in its bipartite graph. To remove this effect, two algorithms are introduced: (1) while generating the graph, the cycle eliminating algorithm is used to reduce the number of the short cycles in it; (2) in the decoding algorithm, cycles that are inevitably in the graph are used to remove decoding efficiency degradation. The simulation results show that they have a better performance than that of general tornado codes.

Optical-spectrum-encoded analog-to-digital converter

A novel optical-spectrum-encoded （OSE） analog-to-digital converter （ADC） is proposed in this letter. To simply exemplify the conversion idea, a 5-bit device structure consisted of Fabry-Perot interferometers （FPI） is analyzed and numericaly simulated. The dependence of peak-transmission wavelength on modulation voltage in an electro-optical FPI and the dependence of transmitted power on incident light wavelength in an FPI are discussed and utilized to implement OSEADC. A linearly tunable mode-locked laser, as a voltage-wavelength transformer and a sampler, and chirped grating FPIs, as an encoder array, can be used to obtain much greater sampling rate and bit-resolution.

STUDY OF SETTING UP THE FOREST RESOURCES MANAGEMENT INFORMATION SYSTEM BASED ON WEBGIS

Based on an analysis of the characteristics of the Forest Resources Management Information System of each development phase, and consideration of the technical trend in Geographic Information System (GIS) in the Internet Age, this paper explores the importance and the feasibility of setting up Forest Resources Management Information System based on the WEBGIS. At the same time, based on the experience of our study, the paper explores the function, structure and method of developing the Forest Resources Management Information System based on WEBGIS. With the technology of WEBGIS, the Forest Resources Management Information System with data from Huoditang Farm was set up, which makes a great impact on forest resources management. So setting up the Forest Resources Management Information System based on WEBGIS is a trend of forest resources management. In the course of setting up this system, we must pay attention to following questions: 1) unify data standard and information encoding; 2) change mind.

Development of High-precision Rotary Encoder Using Semiconductor Laser

In this paper, the operation principle of laser rotary encoders is expounded and the optical quadruple frequency technology used in laser rotary encoders is explained, and the design idea of optical system in φ66 mm laser rotary encoder is mainly introduced, as well as the choice of principal devices.

BMP-6 inhibits microRNA-21 expression in breast cancer through repressing 6EF1 and AP-1

MicroRNAs （miRNAs）, which are small noncoding RNA molecules, play important roles in the post-transcriptional regulation process. The microRNA-21 gene （miR-21） has been reported to be highly expressed in various solid tumors, including breast cancer. Bone morphogenetic protein-6 （BMP-6） has been identified as an inhibitor of breast cancer epithelial-mesenchymal transition （EMT） through rescuing E-cadherin expression. We initiated experi- ments to identify the relationships between miR-21 and BMP-6 in breast cancer progression. Real-time PCR analysis showed that miR-21 expression was very high in MDA-MB-231 cells that expressed little BMP-6. A reverse correla- tion between BMP-6 and miR-21 was also determined in breast cancer tissue samples. Moreover, BMP-6 inhibited miR-21 transcription in MDA-MB-231 cells. In order to investigate how BMP-6 inhibited the miR-21 promoter （miPPR-21）, we constructed a series of miPPR-21 reporters. Luciferase assay results indicated that BMP-6 inhibited miPPR-21 activity through the E2-box and AP-l-binding sites. We also demonstrated that both δEF1 and TPA in- duced miR-21 expression. Using site-directed mutation and CHIP assay, we found that δEF1 induced miPPR-21 ac- tivity by binding to the E2-box on miPPR-21. Moreover, TPA triggered miPPR-21 activity through the AP-I binding sites. BMP-6 treatment significantly reduced the binding of these factors to miPPR-21 by decreasing the expression of δEF1 and c-Fos/c-Jun. We also demonstrated that BMP-6-induced downregulation of miR-21 modified the activ- ity of PDCD4 3＇UTR and inhibited MDA-MB-231 cell invasion. δEF1 overexpression and TPA induction blocked this inhibitory effect of BMP-6. In conclusion, BMP-6-induced inhibition of miR-21 suggests that BMP-6 may function as an anti-metastasis factor by a mechanism involving transcriptional repression of miR-21 in breast cancer.

Hepatitis B virus X protein accelerates the development of hepatoma

The chronic infection of hepatitis B virus(HBV) is closely related to the occurrence and development of hepatocellular carcinoma(HCC). Accumulated evidence has shown that HBV X protein(HBx protein) is a multifunctional regulator with a crucial role in hepatocarcinogenesis. However, information on the mechanism by which HBV induces HCC is lacking. This review focuses on the pathological functions of HBx in HBV-induced hepatocarcinogenesis. As a transactivator, HBx can modulate nuclear factor kappa-light-chain-enhancer of activated B cells(NF-κB) and transcription factor AP-2. Moreover, HBx can affect regulatory non-coding RNAs(ncRNAs) including microRNAs and long ncRNAs(lncRNAs), such as miRNA-205 and highly upregulated in liver cancer(HULC), respectively. HBx is also involved in epigenetic modification, including methylation and acetylation. HBx interacts with various signal-transduction pathways, such as protein kinase B/Akt, Wnt/β-catenin, signal transducer and activator of transcription, and NF-κB pathways. Moreover, HBx affects cellular fate by shifting the balance toward cell survival. HBx may lead to the loss of apoptotic functions or directly contributes to oncogenesis by achieving transforming functions, which induce hepatocarcinogenesis. Additionally, HBx can modulate apoptosis and immune response by direct or indirect interaction with host factors. We conclude that HBx hastens the development of hepatoma.