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Supporting mobility for internet cars

Zhenkai Zhu, Lixia Zhang, Ryuji Wakikawa
2011 IEEE Communications Magazine  
AUTOMOTIVE NETWORKING AND APPLICATIONS Zhenkai Zhu and Lixia Zhang, University of California, Los Angeles Ryuji Wakikawa, Toyota Infotechnology Center Supporting Mobility for Internet Cars standards  ...  LIXIA ZHANG [M] (lixia@cs.ucla.edu) is a professor in the Computer Science Department of UCLA.  ... 
doi:10.1109/mcom.2011.5762816 fatcat:24igmzsy4fggdcoq3mvzdrg4km

ACT

Zhenkai Zhu, Sen Wang, Xu Yang, Van Jacobson, Lixia Zhang
2011 Proceedings of the ACM SIGCOMM workshop on Information-centric networking - ICN '11  
/ucla.edu/cs/zhenkai) is used by each speaker for its voice data.  ...  Figure 3: Conference Discovery A typical name for a data segment may look like: /ucla.edu-/cs/zhenkai/[device-id]/[codec-name]/[seg-num].  ... 
doi:10.1145/2018584.2018601 dblp:conf/acmicn/ZhuWYJ011 fatcat:lnogixepvbcsfhqsngxdewdgke

High confidence embedded software design

Zhenkai Zhang, Joseph Porter, Nicholas Kottenstette, Xenofon Koutsoukos, Janos Sztipanovits
2011 ACM SIGBED Review  
Traditional design methodology is not suitable for high-confidence embedded software due to the lack of a formal semantic model for software analysis, automatic code generation, and often designed embedded software is hard to reuse. In order to automatically generate high-confidence and reusable embedded software, we propose a TLM-centric, platform-based, time-triggered and component-oriented method. We use this new method to generate the control software for a quadrotor helicopter.
doi:10.1145/2000367.2000377 fatcat:te3hnnvq5beuzetxqsabd7tusa

Precise Multi-level Inclusive Cache Analysis for WCET Estimation

Zhenkai Zhang, Xenofon Koutsoukos
2015 2015 IEEE Real-Time Systems Symposium  
Multi-level inclusive caches are often used in multicore processors to simplify the design of cache coherence protocol. However, the use of such cache hierarchies poses great challenges to tight worst-case execution time (WCET) estimation due to the possible invalidation behavior. Traditionally, multi-level inclusive caches are analyzed in a level-by-level manner, and at each level three analyses (i.e. must, may, and persistence) are performed separately. At a particular level, conservative
more » ... sions need to be made when the behaviors of other levels are not available, which hurts analysis precision. In this paper, we propose an approach which analyzes a multi-level inclusive cache by integrating the three analyses for all levels together. The approach is based on the abstract interpretation of a concrete operational semantics defined for multi-level inclusive caches. We evaluate the proposed approach and also compare it with two state-of-theart approaches. From the experimental results, we can observe the proposed approach can significantly improve the analysis precision under relatively small cache size configurations.
doi:10.1109/rtss.2015.40 dblp:conf/rtss/ZhangK15 fatcat:ihazjlcsifcsrpht765om7gaq4

A NOVEL LPI METHOD OF RADAR'S ENERGY CONTROL

Zhenkai Zhang, Jian-Jiang Zhou
2012 Progress In Electromagnetics Research C  
A novel radar energy control strategy based on an improved Interacting Multiple Model Particle Filter (IMMPF) tracking method is presented in this paper. Firstly, the IMMPF tracking method is improved by increasing the weight of the particle which is close to the system state and updating the model probability of every particle. Based on this improved IMMPF method, an energy control method for Low Probability of Intercept (LPI) is then presented, which controls the emission time and power of
more » ... ar according to the target's range and radar cross section (RCS), under the condition of constant detection probability. The tracking accuracy and LPI performance are demonstrated in the Monte Carlo simulations. The results are validated through the comparisons with other methods.
doi:10.2528/pierc12080303 fatcat:kqsrj24f7jfglmrhoa6m4qa644

Understanding Rowhammer Attacks through the Lens of a Unified Reference Framework [article]

Xiaoxuan Lou, Fan Zhang, Zheng Leong Chua, Zhenkai Liang, Yueqiang Cheng, Yajin Zhou
2019 arXiv   pre-print
Rowhammer is a hardware-based bug that allows the attacker to modify the data in the memory without accessing it, just repeatedly and frequently accessing (or hammering) physically adjacent memory rows. So that it can break the memory isolation between processes, which is seen as the cornerstone of modern system security, exposing the sensitive data to unauthorized and imperceptible corruption. A number of previous works have leveraged the rowhammer bug to achieve various critical attacks. In
more » ... is work, we propose a unified reference framework for analyzing the rowhammer attacks, indicating three necessary factors in a practical rowhammer attack: the attack origin, the intended implication and the methodology. Each factor includes multiple primitives, the attacker can select primitives from three factors to constitute an effective attack. In particular, the methodology further summarizes all existing attack techniques, that are used to achieve its three primitives: Location Preparation (LP), Rapid Hammering (RH), and Exploit Verification (EV). Based on the reference framework, we analyze all previous rowhammer attacks and corresponding countermeasures. Our analysis shows that how primitives in different factors are combined and used in previous attacks, and thus points out new possibility of rowhammer attacks, enabling proactive prevention before it causes harm. Under the framework, we propose a novel expressive rowhammer attack that is capable of accumulating injected memory changes and achieving rich attack semantics. We conclude by outlining future research directions.
arXiv:1901.03538v1 fatcat:dgfw3m6p4fchfij43qvmw2xzri

Image quality assessment metrics with Radon transform

Jianxin Pang, Rong Zhang, Hui Zhang, Xuan Huang, Zhenkai Liu
2008 Conference Proceedings / IEEE International Conference on Systems, Man and Cybernetics  
Objective image quality assessment (QA) is a fundamental and challenging job in image processing which evaluates the image quality consistently with human perception automatically. Generally, an image can be segmented into two kinds of areas: structure and texture. And structural information plays a much more important role between the two. The pixels, edges and shape with directional characteristic contribute much more to the structural information. In this paper, the structural information is
more » ... modeled as the energy of directional projection, which is shown in a directional projection-based map that is built by Radon transform. On the assumption that any image's distortion could be modeled as the difference between the directional projection-based maps of reference and distortion images, we propose a new objective quality assessment method with Radon transform for full reference model, and we also try to explore the feasibility to develop the image QA metrics with scalable efficiency and computational cost. Experimental results show that the proposed Metrics are well consistent with the subjective quality score. Keywords-image quality assessment, signal projection, Radon transform, objective quality I.
doi:10.1109/icsmc.2008.4811626 dblp:conf/smc/PangZZHL08 fatcat:g6abfdpz75actnc3sozlfdpqgi

Deep Sea TDOA Localization Method Based on Improved OMP Algorithm

Feng Jiang, Zhenkai Zhang, Hamid Esmaeili Najafabadi
2019 IEEE Access  
ZHENKAI ZHANG received the Ph.D. degree in signal and information processing from the Nanjing University of Aeronautics and Astronautics.  ... 
doi:10.1109/access.2019.2954330 fatcat:muvr5vddkbg65pgxopmjoswamu

A Node Selection Algorithm Based on Multi-Objective Optimization Under Position Floating

Shengkai Tian, Zhenkai Zhang
2022 IEEE Access  
Almost all existing node selection algorithms of the underwater sensor networks (USNs) are designed by assuming ideal environments. However, the position floating of the underwater sensor nodes which caused by ocean currents cannot be ignored in practice. Aiming at solving this problem during underwater target tracking, a node selection algorithm based on multi-objective optimization under position floating was proposed in this paper. First, the error caused by position floating is converted
more » ... o a floating noise. Then, as the criteria for node selection, both Fisher information matrix (FIM) and mutual information (MI) under position floating are derived by the particle filter under position floating (PF-PF). Finally, the number of nodes, the corresponding FIM and MI are set as the objective function, both nondominated sorting genetic algorithm II (NSGA-II) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) are used to find the optimal node selection scheme. Simulation results show that the proposed algorithm can overcome the influence of position floating, and ultimately, its tracking performance is more stable and accurate.
doi:10.1109/access.2022.3167642 fatcat:tqxdamo3crbvbp5pqznlim5ik4

A NOVEL DATA ASSOCIATION ALGORITHM BASED ON FCM-DFA

Zhenkai Zhang, Jialin Cheng, Jie Wu
2017 ICIC Express Letters  
In order to obtain higher correct correlation rate under the condition of high track density in multiple target tracking system, it is very necessary to improve association accuracy. In this paper, a data association algorithm based on fuzzy c-means clustering (FCM) and discriminative feature algorithm (DFA) is presented. Every time the membership degree matrix between measurements and clustering center will be computed. Membership degree matrix is designed to represent the association degree
more » ... tween the measurements and tracks. According to the maximal element of each sensor's membership degree matrix, if the measurement is not associated with any track, the discriminative feature will be utilized to determine the measurement ownership. The proposed algorithm is realized in the simulation experiment, which compares FCM-DFA with the nearest neighbors data association algorithm (NNDA), and the simulation result indicates that the proposed algorithm has better correlation rate when the tracks are crossed and the tracking accuracy is better.
doi:10.24507/icicel.11.10.1489 fatcat:5x2jsncabrg43nwjudsaqs3cay

Feifukang ameliorates pulmonary fibrosis by inhibiting JAK-STAT signaling pathway

Hongbo Li, Zhenkai Wang, Jie Zhang, Youlei Wang, Chen Yu, Jinjin Zhang, Xiaodong Song, Changjun Lv
2018 BMC Complementary and Alternative Medicine  
Feifukang (FFK) is a traditional Chinese medicine composed of herbs that protect lung function. However, difficulty arises regarding the clinical application of FFK due to the complex mechanism of Chinese medicines. This study aimed to investigate the efficacy of FFK and explore its targeted genes and pathways. Methods: Histopathological changes and collagen deposition were measured to evaluate the effect of FFK on bleomycin-induced pulmonary fibrosis in mice. The differentially expressed
more » ... ed genes and pathways were first screened using RNA sequencing. Then network pharmacology and other experiments were conducted to confirm RNA sequencing data. Results: FFK treatment reduced the pathological score and collagen deposition, with a decrease in α-SMA and collagen. RNA sequencing and network pharmacology results all showed that FFK can ameliorate pulmonary fibrosis through multi-genes and multi-pathways. The targeted genes in JAK-STAT signaling pathway are some of the most notable components of these multi-genes and multi-pathways. Further experiments illustrated that FFK regulated phosphorylation of SMAD3, STAT3 and JAK1, and their co-expressed lncRNAs, which all are the important genes in JAK-STAT signaling pathway. Conclusion: FFK can ameliorate pulmonary fibrosis by inhibiting JAK-STAT signaling pathway and has potential therapeutic value for lung fibrosis treatment. Our study provides a new idea for the study of traditional Chinese medicine.
doi:10.1186/s12906-018-2297-3 pmid:30092799 pmcid:PMC6085667 fatcat:4jorkjj3djeyhmznfhl7xkpwaa

Factors Affecting the Ratio of Female to Male of Pinewood Nematodes Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle

Pengfei Wei, Yongxia Li, Wei Zhang, Mengge Gao, Zhenkai Liu, Xingyao Zhang
2021 Forests  
The pinewood nematode Bursaphelenchus xylophilus (B. xylophilus) is responsible for a devastating disease of pine forests. Its pathogenicity is closely related to the numbers of individual B. xylophilus. The ratio of female to male (sex ratio) is key to understanding population change in this species. The sex ratio of B. xylophilus varies widely, but it is unclear how it is affected by environmental changes. The sex ratios of nematodes, isolated from different samples in the wild, varied
more » ... 0.93 and 2.20. Under laboratory conditions, maternal age and the population did not affect the sex ratio of progeny. A change from good to poor nutritional status was associated with a reduction of the sex ratio of progeny from 1.85 to 1.41, which was speculated to result from a change in the primary sex ratio. Thus, B. xylophilus effectively maintains the sex ratio with maternal age and population changes but adjusts the sex ratio of progeny on the basis of the changes in nutrition.
doi:10.3390/f12060763 fatcat:lc2dv3kiavdhxemmbphmbdbdge

Cold adaptive potential of pine wood nematodes overwintering in plant hosts

Zhenkai Liu, Yongxia Li, Long Pan, Fanli Meng, Xingyao Zhang
2019 Biology Open  
The pine wood nematode (PWN; Bursaphelenchus xylophilus) is the causal agent of pine wilt disease, which results in severe ecological and economic losses in coniferous forests. During overwintering, PWNs undergo morphological and physiological changes to adapt to low temperature environments. Here, the physiological changes of the PWN populations sampled in the summer and winter were compared to analyze the role of low temperatures in their response. The PWN overwinters as third-stage dispersal
more » ... juveniles, which showed significantly greater survival rates than summer populations ( propagative forms) at sub-zero temperatures. The major biochemical compounds in the populations were analyzed by gas chromatography. Eight dominant fatty acids, with stearic acid being the most important, were identified from PWN propagative stage and third-stage dispersal stage. Compared with the propagative stage, the dispersal stage showed significant increases in the fatty acid content and the proportion of unsaturated fatty acids. Three carbohydrates, trehalose, glycerol and glucose, were detected in the PWN. Compared with the summer population, the levels of trehalose and glycerol increased significantly, while glucose decreased, in the winter population. The modifications in fatty acid composition and cryoprotectant levels, as elements of its changing physiology, play important roles in the overwintering success of the PWN.
doi:10.1242/bio.041616 fatcat:xh6ttfrquvf75co6d3antqvgwm

Pattern Synthesis of Time-Modulated Array Antenna Based on an Improved Invasive Weed Optimization Method

Zhenkai Zhang, Xinxing Liu, Bing Zhang, Hailin Li
2019 International Journal of Antennas and Propagation  
In this paper, pattern synthesis through time-modulated linear array is studied, and a novel strategy for harmonic beamforming in time-modulated array is proposed. The peak side lobe level is designed as optimization objective function, and the switch-on time sequence of each element is selected as optimization variable. An improved invasive weed optimization (IWO) algorithm is developed in order to determine the optimal parameters describing the pulse sequence used to modulate the excitation
more » ... ights of array elements. Representative results are reported and discussed to point out potentialities and advantages of the proposed approach, which can obtain lower objective function values.
doi:10.1155/2019/6243107 fatcat:n54qispmfjcyvfthcb4jif376e

The Establishment and Evaluation Method of Artificial Microcracks in Rocks

Zhenkai Wu, Xizhe Li, Hanmin Xiao, Xuewei Liu, Wei Lin, Yuan Rao, Yang Li, Jie Zhang
2021 Energies  
Zhang et al. (2020) [21] conducted uniaxial compression experiments on a 4 × 8 mm rock sample in order to explore the process of rock compression and deformation and the laws of crack generation.  ... 
doi:10.3390/en14102780 fatcat:cxidaxquljfybghanwowdg42cq
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