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On-Road Vehicle Trajectory Collection and Scene-Based Lane Change Analysis: Part II

IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS 2017年第1期18卷 206-220页

作者： Yao, Wen Zeng, Qiqi Lin, Yuping Xu, Donghao Zhao, Huijing Guillemard, Franck Geronimi, Stephane Aioun, Francois Peking Univ Minist Educ Key Lab Machine Percept Beijing 100871 Peoples R China Grp PSA Peugeot Soc Anonyme F-78943 Velizy Villacoublay France

This two-part paper aims to study lane change behaviors at the tactical level from an on-road perspective. Compared with longitudinal driving tasks, a lane change is more complicated because this task has more interactions with surrounding vehicles;thus, there are more potential risks during this procedure. Based on the results from Part I on an on-road vehicle trajectory collection, this part investigates lane change extraction and scene-based behavior analysis, and it has a particular focus on understanding the interactions between an ego and surrounding vehicles during the procedure. We claim that this paper provides the following novel contributions: 1) an automatic method is proposed for extracting lane change segments from a continuous driving sequence by modeling and recognizing patterns in a steering angle;2) a lane change database at the trajectory level is generated, which reflects the interactions between an ego and the surrounding vehicles during the procedures;and 3) we present findings from analyzing lane change procedures using real-world data on the axes of both the ego's trajectory and interactions with the scene vehicles. To the authors' knowledge, this is the first lane change behavior study from an on- road perspective that addresses the vehicle interactions in real-world traffic at the trajectory level.

关键词： Driving behavior lane change scene-based analysis vehicle interaction trajectory

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Galvanic Deposition of Copper, Silver and Gold on Silicon Surfaces from Fluoride-free Aqueous Solutions 230

Galvanic Deposition of Copper, Silver and Gold on Silicon Su...

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Symposium on Electroless Deposit - Principles and Applicat 4 - In Honor of Milan Paunov and Mordechay Schlesinger held during the PRiME Joint Int Meeting of the Electrochem-Soc, the Electrochem-Soc-of-Japan, and the Korean-Electrochem-Soc

作者： Djokic, Stojan S. Elchem Consulting Ltd Edmonton AB T5X 6B3 Canada

ISBN: (纸本)9781607687832

Deposition of copper, silver and gold onto silicon surfaces is investigated in this work. Traditionally, direct deposition of Cu, Ag and Au onto silicon surfaces is carried out using fluoride based solutions. In the fluoride based solutions unavoidably present SiO2 at the surface of semiconductor is successfully removed and then deposition of metals such as Au or Ag proceeds via the galvanic displacement process. The results of the present work demonstrate that the direct deposition of Cu, Ag or Au onto silicon surface is very successful from fluoride-free alkaline solutions containing Cu(II), Ag(I) or Au(I) ions at pH higher than 12. The deposition of these metals does not require a reducing agent, i.e. process proceeds via galvanic displacement reactions. The approach can further be applied on any metal with the standard electrode potential more positive than that of silicon, as long as the alkaline complexes of the targeted metals are reasonably stable in the strong alkaline electrolytes with pH more than 12.

关键词： Metals

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Motion Analysis and Trials of the Deep Sea Hybrid Underwater Glider Petrel-Ⅱ

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china Ocean Engineering 2017年第1期31卷 55-62页

作者： LIU Fang WANG Yan-hui WU Zhi-liang WANG Shu-xin Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin 300072China Yichang Research Institute of Testing Technology Yichang 443003China

A hybrid underwater glider Petrel-II has been developed and field tested. It is equipped with an active buoyancy unit and a compact propeller unit. Its working modes have been expanded to buoyancy driven gliding and propeller driven level-flight, which can make the glider work in strong currents, as well as many other complicated ocean environments. Its maximal gliding speed reaches 1 knot and the propelling speed is up to 3 knots. In this paper, a 3D dynamic model of Petrel-II is derived using linear momentum and angular momentum equations. According to the dynamic model, the spiral motion in the underwater space is simulated for the gliding mode. Similarly the cycle motion on water surface and the depth-keeping motion underwater are simulated for the level-flight mode. These simulations are important to the performance analysis and parameter optimization for the Petrel-II underwater glider. The simulation results show a good agreement with field trials.

关键词： hybrid underwater glider dynamic model numerical simulation underwater vehicles

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Random Radiation Source Optimization Method for Microwave Staring Correlated Imaging Based on Temporal-Spatial Relative Distribution Entropy

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PROGRESS IN ELECTROMAGNETICS research M 2018年 63卷 195-206页

作者： Meng, Qingquan Qian, Tingting Yuan, Bo Wang, Dongjin Univ Sci & Technol China Chinese Acad Sci Key Lab Electromagnet Space Informat Hefei 230027 Anhui Peoples R China

Microwave Staring Correlated Imaging (MSCI) is a high-resolution radar imaging modality, whose resolution is mainly determined by the randomness of radiation source. To optimize the design of random radiation source, a novel concept of temporal-spatial relative distribution entropy (TSRDE) is proposed to describe the temporal-spatial stochastic characteristics of radiation source. The TSRDE can be utilized as the optimization criterion to design the array configuration and signal parameters by means of optimization algorithms. In this paper the genetic algorithm is applied to search for the best design. Numerical simulations are performed and the results show that the TSRDE is an effective method to characterize the randomness of radiation source, and the source parameters optimized by this method can dramatically improve the imaging resolution.

关键词： Random processes

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Exploiting distinctive topological constraint of local feature matching for logo image recognition

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NEUROCOMPUTING 2017年 236卷 113-122页

作者： Tang, Panpan Peng, Yuxin Peking Univ Inst Comp Sci & Technol Beijing 100871 Peoples R China

Robust local feature matching plays an important role in the challenging task of logo image recognition. Most traditional methods consider the individual local feature but ignore the affine-invariant geometric relationship among the adjacent local features, which is essential to reduce the number of mismatching. In addition, they do matching for all of the local features and ignore that many ones are insignificant, which increase the probability of mismatching and the computation complexity. To address the two limitations, we propose a robust matching method to get the better matching results by exploiting the distinctive topological constraint together with the feature selection. In the proposed method, first we employ the distinctive topological constraint to enhance the describing ability of local features, which makes full use of the affine-invariant geometric relationship among adjacent local features for more accurate local feature matching. Second, we utilize the feature selection algorithm based on the mutual information (MI), to filter out most insignificant local features before matching, which is efficient and effective to guarantee the performance of local feature matching. We evaluated the proposed method on two challenging datasets, i.e, FlickrLogos-32 and FlickrLogos-27, and achieve superior performance against the state-of-the-art methods in the literature.

关键词： Local feature matching Distinctive topological constraint Feature selection Logo image recognition

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MULTIMEDIA TOOLS AND APPLICATIONS 2017年第23期76卷 25109-25127页

作者： Qi, Jinwei Huang, Xin Peng, Yuxin Peking Univ Inst Comp Sci & Technol Beijing 100871 Peoples R China Peking Univ ICST MIPL Beijing Peoples R China

As a highlighting research topic in the multimedia area, cross-media retrieval aims to capture the complex correlations among multiple media types. Learning better shared representation and distance metric for multimedia data is important to boost the cross-media retrieval. Motivated by the strong ability of deep neural network in feature representation and comparison functions learning, we propose the Unified Network for Cross-media Similarity Metric (UNCSM) to associate cross-media shared representation learning with distance metric in a unified framework. First, we design a two-pathway deep network pretrained with contrastive loss, and employ double triplet similarity loss for fine-tuning to learn the shared representation for each media type by modeling the relative semantic similarity. Second, the metric network is designed for effectively calculating the cross-media similarity of the shared representation, by modeling the pairwise similar and dissimilar constraints. Compared to the existing methods which mostly ignore the dissimilar constraints and only use sample distance metric as Euclidean distance separately, our UNCSM approach unifies the representation learning and distance metric to preserve the relative similarity as well as embrace more complex similarity functions for further improving the cross-media retrieval accuracy. The experimental results show that our UNCSM approach outperforms 8 state-of-the-art methods on 4 widely-used cross-media datasets.

关键词： Cross-media retrieval Representation learning Metric learning

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Global optimum encoding packet selection mechanism based on opportunistic network coding for wireless network retransmission

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The Journal of china Universities of Posts and Telecommunications 2017年第1期24卷 47-59页

作者： Wang Lian Peng Daiyuan Liang Hongbin School of Information Science and Technology Southwest Jiaotong University Chengdu 610031 China School of Computing Science and Technology Chongqing University of Posts and Telecommunications Chongqing 400065 China School of Transportation and Logistics Southwest Jiaotong University Chengdu 610031 China School of Computing Informatics and Decision Systems Engineering Arizona State University Tempe AZ 85281-8809 USA

Packet loss cannot be avoided in wireless network due to wireless transmission medium particularity, therefore improving retransmission efficiency is meaningful to wireless transmission. The current retransmission packet selection mechanisms based on oppornistic network coding （ONC） face low retransmission efficiency and high computational complexity problems. To these problems, an optimized encoding packet selection mechanism based on ONC in wireless network retransmission （OONCR） is proposed. This mechanism is based on mutual exclusion packets and decoding gain concepts, and makes full use of ONC advantages. The main contributions of this scheme are to control the algorithm eomplexity of the maximum encoding packets selection effectively, avoid the redundancy encoding packets due to the overlapping among encoding packets, and take the encoding packet local and global optimization problem into consideration. Retransmission efficiency is evaluated according to the computational complexity, the throughput, the retransmission redundancy ratio, and the number of average retransmission. Under the various conditions, the number of average retransmission of OONCR is mainly lower than that of other typical retransmission packet selection schemes. The average retransmission redundancy ratios of OONCR are lower about 5%-40% compared with other typical schemes. Simultaneously the computational complexity of OONCR is comparatively lower than that of other typical schemes.

关键词： wireless network retransmission network coding throughput

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Cross-media retrieval by exploiting fine-grained correlation at entity level

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NEUROCOMPUTING 2017年 236卷 123-133页

作者： Huang, Lei Peng, Yuxin Peking Univ Inst Comp Sci & Technol Beijing 100871 Peoples R China

Cross-media retrieval is to submit data of any media type, and get semantically relevant results of different media types. Most existing approaches project low-level features of cross-media data onto a unified feature space. However, some of these feature spaces usually have no explicit semantics, which ignore the intrinsic semantic information contained in the original media content. The others only have coarse-grained semantics suffering from the ambiguity of high-level concepts, because the coarse-grained correlation between low-level features and high-level concepts is simply utilized. Hence, the aforementioned approaches cannot generate the descriptive representation of media content, leading to reduced effectiveness to measure the semantic similarities among cross-media data. To address the above problems, we propose a novel approach to cross media retrieval by exploiting the fine-grained correlation at the entity level and generating the unified descriptive representation. Concretely, the proposed approach first constructs an entity level with fine-grained semantics between low-level features and high-level concepts. Second, by minimizing (maximizing) the distances between media content with positive (negative) correlation at the entity level, we learn the distance-preserving entity projections (DPEP) and generate the unified descriptive representation of media content. Experimental results on two publicly available datasets demonstrate the effectiveness of our approach.

关键词： Cross-media retrieval Entity level Fine-grained correlation Distance-preserving entity projection

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Morphology-Controlled Preparation of -Calcium Sulfate Hemihydrate from Phosphogypsum by Semi-Liquid Method

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CRYSTAL research AND techNOLOGY 2018年第1期53卷

作者： Mi, Yang Chen, Deyu He, Yulong Wang, Shuzhou Southwest Univ Sci & Technol Sch Mat Sci & Engn Mianyang 621010 Sichuan Peoples R China

Phosphogypsum (PG), a by-product of phosphoric acid industry, causes environmental issues. In this paper, PG was effectively transformed into alpha-calcium sulfate hemihydrate (?-CSH) via a semi-liquid method. The phase evolution and the effects of different organic acids and pH values on crystal morphology of the -CSH were investigated by SEM, XRD and EDS. The properties of the prepared -CSH with different aspect ratio were also compared. The results indicate that PG can be successfully transformed into -CSH by the semi-liquid method at 140 degrees C for 3.0 h. The morphology of the produced -CSH is significantly influenced by the concentrations of organic acid and pH value. -CSH crystal with well-morphology is obtained under the condition of 0.1wt.% maleic acid and pH = 7.0. The obtained -CSH with uniform particle size has the aspect ratio of 1.2. The 2 h and 3 d bending/compressive strengths of the hardened paste prepared from the -CSH reach 6.4/20.6 MPa and 10.5/43.7 MPa respectively, which are comparable to those of the commercial -CSH. Moreover, the lower aspect ratio of ?-CSH results in more compact microstructure and higher mechanical strengths of the hardened paste.

关键词： crystal morphology phase transformation phosphogypsum semi-liquidmethod -calcium sulfate hemihydrate

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Design of novel sliding-mode controller for high-velocity AUV with consideration of residual dead load

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Journal of Central South University 2018年第1期25卷 121-130页

作者： JIANG Chun-meng WAN Lei SUN Yu-shan LI Yue-ming Science and Technology on Underwater Vehicle Laboratory Harbin Engineering University

This work focuses on motion control of high-velocity autonomous underwater vehicle(AUV).Conventional methods are effective solutions to motion control of low-and-medium-velocity *** not taken into consideration in the control model,the residual dead load and damping force which vary with the AUV’s velocity tend to result in difficulties in motion control or even failure in convergence in the case of high-velocity *** full consideration given to the influence of residual dead load and changing damping force upon AUV motion control,a novel sliding-mode controller(SMC)is proposed in this *** stability analysis of the proposed controller is carried out on the basis of Lyapunov *** sea trials results proved the superiority of the sliding-mode controller over sigmoid-function-based controller(SFC).The novel controller demonstrated its effectiveness by achieving admirable control results in the case of high-velocity movement.

关键词： autonomous underwater vehicle sliding-mode control stability analysis residual dead load sigmoid-function-based control

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