Queue Analysis and Multiplexing of Heavy-tailed Traffic in Wireless Packet Data Networks

Recent research based on traffic measurements shows that Internet traffic flows have a fractal nature (i.e., self-similarity property), which causes an underestimation of network engineering parameters when using the conventional Poisson model. Preliminary field measurements demonstrate that packet data traffic in wireless communications also exhibits self-similarity. In this paper, we investigate the queuing behavior of self-similar traffic flows for data applications in a packet-switching single-server wireless network. The traffic is generated by an on–off source with heavy-tailed on periods and exponentially distributed off periods. We extend previous analysis of a relation among the asymptotic distribution of loss probability, traffic specifications, and transmission rate for a wireline system to a wireless system, taking into account wireless propagation channel characteristics. We also investigate the multiplexing of heavy-tailed traffic flows with a finite buffer for the downlink transmission of a wireless network. Computer simulation results demonstrate that assumptions made in the theoretical analysis are reasonable and the derived relationships are accurate.     

半导体激光器电噪声的软件分析

对半导体激光器(LD)电噪声特性进行了小波分析,定位g-r噪声转折频率.根据LabVIEW6.0软件的虚拟仪器特性,设计了虚拟的FFT分析仪,实现LD电噪声的时域波形显示、谱分析、互谱分析、谱密度分析以及频率响应分析.     

基于VMD和改进TCN的短期光伏发电功率预测

光伏发电功率存在波动性,且光伏出力易受各种气象特征影响,传统TCN网络容易过度强化空间特性而弱化个体特性。针对上述问题,文中提出一种基于VMD和改进TCN的短期光伏发电功率预测模型。通过VMD将原始光伏发电功率时间序列分解为若干不同频率的模态分量,将各个模态分量以及相对应的气象数据输入至改进TCN网络进行建模学习。利用中心频率法确定VMD的最优分解模态分解个数。在传统TCN预测模型的基础上,使用DropBlock正则化取代Dropout正则化以达到抑制卷积层中信息协同的效果,并引入注意力机制自主挖掘并突出关键气象输入特征的影响,量化各气象因素对光伏发电的影响,从而提高预测精度。以江苏省某光伏电站真实数据为例进行仿真实验,结果表明所提预测方法的RMSE为0.62 MW,MAPE为2.03%。     

Rethinking PASCAL-VOC and MS-COCO dataset for small object detection

The data and the algorithm are critical to deep learning-based small object detectors. In this paper, we rethink the PASCAL-VOC and MS-COCO dataset for small object detection. By visual analysis of the original annotations, we find that there are different labeling errors in these two datasets. To solve these problems, we build specific datasets, including SDOD, Mini6K, Mini2022 and Mini6KClean. The experimental results of several typical algorithms (e.g. SSD, YOLOv5, Faster RCNN and Deformable DETR) on the datasets show that data labeling errors (such as missing labels, category label errors, inappropriate labels) are another factor that affects the detection performance of small objects.     

A post quantum secure construction of an authentication protocol for satellite communication

Satellite's communication system is used to communicate under significant distance and circumstances where the other communication systems are not comfortable. Since all the data are exchanged over a public channel, so the security of the data is an essential component for the communicating parties. Both key exchange and authentication are two cryptographic tools to establish a secure communication between two parties. Currently, various kinds of authentication protocols are available to establish a secure network, but all of them depend on number–theoretical (discrete logarithm problem/factorization assumption) hard assumptions. Due to Shor's and Grover's computing algorithm number theoretic assumptions are breakable by quantum computers. Although Kumar and Garg have proposed a quantum attack-resistant protocol for satellite communication, it cannot resist stolen smart card attack. We have analyzed that how Kumar and Garg is vulnerable to the stolen smart card attack using differential power analysis attack described in He et al and Chen and Chen. We have also analyzed the modified version of signal leakage attack and sometimes called improved signal leakage attack on Kumar and Garg's protocol. We have tried to construct a secure and efficient authentication protocol for satellites communication that is secure against quantum computing. This is more efficient as it requires only three messages of exchange. This paper includes security proof and performance of the proposed authentication and key agreement protocol.     

FDTD based transition time dependent crosstalk analysis for coupled RLC interconnects

The performance of high density chips operating in the GHz range is mostly affected by on-chip interconnects. The interconnect delay depends on many factors, a few of them are inputs toggling patterns, line ＆ coupling parasitics, input rise/fall time and source/load characteristics. The transition time of the input is of prime importance in high speed circuits. This paper addresses the FDTD based analysis of transition time effects on functional and dynamic crosstalk. The analysis is carried out for equal and unequal transition times of coupled inputs. The analysis of the effects of unequal rise time is equally important because practically, it is quite common to have mismatching in the rise time of the signals transmitting through different length wires. To demonstrate the effects, two distributed RLC lines coupled inductively and capacitively are taken into consideration. The FDTD technique is used because it gives accurate results and carries time domain analysis of coupled lines. The number of lumps in SPICE simulations is considered the same as those of spatial segments. To validate the FDTD computed results, SPICE simulations are run and results are compared. A good agreement of the computed results has been observed with respect to SPICE simulated results. An average error of less than 3.2% is observed in the computation of the performance parameters using the proposed method.     

Y型光子晶体偏振光分束器

基于偏振模式不同的光波在二维光子晶体中的传播特性不同,设计出一个支路半径相同的Y型二维光子晶体偏振光分束器.通过时域有限差分法对该分束器进行数值计算与模拟分析.结果表明,该分束器能够实现TE模和TM模平行、高效分束.当波长为1.55μm的高斯脉冲入射时,TE模透射率可达97%,TM模透射率可达93.5%,且该结构尺寸仅有6.3μm×6.8μm.这些特性使其在未来的集成光路中具有很好的应用前景.     

星载双极化SAR冬小麦物候期识别方法

冬小麦是中国主要的粮食作物之一,准确及时地获取冬小麦物候信息是冬小麦长势监测和产量预估的必要条件。星载合成孔径雷达(SAR)是一种微波遥感设备,具有全天时、全天候的优势,可实现对周期性农作物物候期大范围监测。基于时间序列Sentinel-1A SAR数据,提出一种星载双极化SAR冬小麦物候期识别方法。该方法基于特征值分解和极化散射分析技术,提取不同物候期冬小麦的后向散射系数、极化熵、主导散射角等参数,实现冬小麦物候期识别。实验结果表明,物候期识别总体精确度达到79%。该方法在冬小麦生长监测方面具有实用推广价值。     

高剂量离子注入直接形成Ge纳米晶的物理机理

研究了单束双能高剂量Ge离子注入、不经过退火在非晶态SiO2薄膜中直接形成镶嵌结构Ge纳米晶的物理机制．实验中利用不加磁分析器的离子注入机，采用Ge弧光放电离化自动形成的Ge+和Ge2+双电荷离子并存的单束双能离子注入方法，制备了1e16～1e18cm－2多种剂量Ge离子注入的Si基SiO2薄膜样品．用GIXRD表征了Ge纳米晶的存在，并仔细分析得到了纳米晶形成的阈值剂量．通过TEM分析了Ge纳米晶的深度分布和晶粒尺寸．用SRIM程序分别计算了双能离子在SiO2非晶层的射程和深度分布，与实验结合，得到纳米晶形成的物理机制，即纳米晶的形成与单束双能离子注入时Ge＋和Ge2＋相互碰撞产生的能量沉积在SiO2中形成的局域高温有关．     

The Coupling Model for Function and Delay Faults

We propose a high-level fault model, the coupling fault (CF) model, that aims to cover both functional and timing faults in an integrated way. The basic properties of CFs and the corresponding tests are analyzed, focusing on their relationship with other fault models and their test requirements. A test generation program COTEGE for CFs is presented. Experiments with COTEGE are described which show that (reduced) coupling test sets can efficiently cover standard stuck-at-0/1 faults in a variety of different realizations. The corresponding coupling delay tests detect all robust path delay faults in any realization of a logic function. This research was sponsored in part by the U.S. National Science Foundation under Grants No. CCR-9872066 and CCR-0073406. Joonhwan Yi received the B.S degree in electronics engineering from Yonsei University, Seoul, Korea, in 1991, and the M.S. and Ph.D degrees in electrical engineering and computer science from the University of Michigan, Ann Arbor, in 1998 and 2002, respectively. From 1991 to 1995, he was with Samsung Electronics, Semiconductor Business, Korea, where he was involved in developing application specific integrated circuit cell libraries. In 2000, he was a summer intern with Cisco, Santa Clara, CA, where he worked for path delay fault testing. Since 2003, he has been with Samsung Electronics, Telecommunication Network, Suwon, Korea, where he is working on system-on-a-chip design. His current research interests include C-level system modeling for fast hardware and software co-simulation, system-level power analysis and optimization, behavioral synthesis, and high-level testing. John P. Hayes received the B.E. degree from the National University of Ireland, Dublin, and the M.S. and Ph.D. degrees from the University of Illinois, Urbana-Champaign, all in electrical engineering. While at the University of Illinois, he participated in the design of the ILLIAC III computer. In 1970 he joined the Operations Research Group at the Shell Benelux Computing Center in The Hague, where he worked on mathematical programming and software development. From 1972 to 1982 he was a faculty member of the Departments of Electrical Engineering– Systems and Computer Science of the University of Southern California, Los Angeles. Since 1982 he has been with the Electrical Engineering and Computer Science Department of the University of Michigan, Ann Arbor, where he holds the Claude E. Shannon Chair in Engineering Science. Professor Hayes was the Founding Director of the University of Michigan's Advanced Computer Architecture Laboratory (ACAL). He has authored over 225 technical papers, several patents, and five books, including Introduction to Digital Logic Design (Addison-Wesley, 1993), and Computer Architecture and Organization, (3rd edition, McGraw-Hill, 1998). He has served as editor of various technical journals, including the Communications of the ACM, the IEEE Transactions on Parallel and Distributed Systems and the Journal of Electronic Testing. Professor Hayes is a fellow of both IEEE and ACM, and a member of Sigma Xi. He received the University of Michigan's Distinguished Faculty Achievement Award in 1999 and the Humboldt Foundation's Research Award in 2004. His current teaching and research interests are in the areas of computer-aided design, verification, and testing; VLSI circuits; fault-tolerant embedded systems; ad-hoc computer networks; and quantum computing.