检索结果-南通市图书馆

Fast-armored target detection based on multi-scale representation and guided anchor

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2020年第4期16卷 922-932页

作者： Fan-jie Meng Xin-qing Wang Fa-ming Shao dong Wang xiao-dong hu Department of Mechanical Engineering College of Field EngineeringArmy Engineering University of PLANanjing210007China

Focused on the task of fast and accurate armored target detection in ground battlefield,a detection method based on multi-scale representation network(MS-RN) and shape-fixed Guided Anchor(SF-GA)scheme is ***,considering the large-scale variation and camouflage of armored target,a new MS-RN integrating contextual information in battlefield environment is *** MS-RN extracts deep features from templates with different scales and strengthens the detection ability of small *** targets of different sizes are detected on different representation ***,aiming at the accuracy and real-time detection requirements,improved shape-fixed Guided Anchor is used on feature maps of different scales to recommend regions of interests(ROIs).Different from sliding or random anchor,the SF-GA can filter out 80% of the regions while still improving the recall.A special detection dataset for armored target,named Armored Target Dataset(ARTD),is constructed,based on which the comparable experiments with state-of-art detection methods are *** results show that the proposed method achieves outstanding performance in detection accuracy and efficiency,especially when small armored targets are involved.

关键词： red image RPN Fast-armored target detection based on multi-scale representation and guided anchor

Improved Algorithm for Broadcast Scheduling of Minimal Latency in Wireless Ad Hoc Networks

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2010年第1期26卷 13-22页

作者： Wei-ping Shang Peng-jun Wan xiao-dong hu Department of Mathematics Zhengzhou University Zhengzhou 450052 China Department of Computer Science Illinois Institute of Technology Chicago IL 60616 USA Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

A wide range of applications for wireless ad hoc networks are time-critical and impose stringent requirement on the communication latency. One of the key communication operations is to broadcast a message from a source node. This paper studies the minimum latency broadcast scheduling problem in wireless ad hoc networks under collision-free transmission model. The previously best known algorithm for this NP-hard problem produces a broadcast schedule whose latency is at least 648（rmax/rmin）^2 times that of the optimal schedule, where rmax and rmin are the maximum and minimum transmission ranges of nodes in a network, respectively. We significantly improve this result by proposing a new scheduling algorithm whose approximation performance ratio is at most （1 ＋ 2rmax/rmin）^2＋32, Moreover, under the proposed scheduling each node just needs to forward a message at most once.

关键词： Broadcast latency wireless ad hoc networks approximation algorithm

Molecular insight into the oil displacement mechanism of CO_(2) flooding in the nanopores of shale oil reservoir

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2023年第6期20卷 3516-3529页

作者： xiao-hu dong Wen-Jing Xu hui-Qing Liu Zhang-Xing Chen Ning Lu State Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China MOE Key Laboratory of Petroleum Engineering China University of PetroleumBeijing102249China Department of Chemical and Petroleum Engineering University of CalgaryCalgaryAlbertaT2N 1N4Canada

With the increasing demand for petroleum,shale oil with considerable reserves has become an important part of global oil *** shale oil reservoir has a large number of nanopores and a complicated mineral composition,and the effect of nanopore confinement and pore type usually makes the effective development of shale oil *** a shale oil reservoir,CO_(2) flooding can effectively reduce the oil viscosity and improve the reservoir properties,which can thus improve the recovery *** this study,the method of non-equilibrium molecular dynamics(NEMD)simulation is used to simulate the CO_(2) flooding process in the nanoscale pores of shale oil *** performance difference between the organic kerogen slit nanopore and four types of inorganic nanopores is ***,the effects of nanopore type and displacement velocity on the nanoscale displacement behavior of CO_(2) are *** indicate that the CO_(2) flooding process of different inorganic pores is *** comparison,the displacement efficiency of light oil components is higher,and the transport distance is *** intermolecular interaction can significantly affect the CO_(2) displacement behavior in *** CO_(2) displacement efficiency is shown as montmorillonite,feldspar>quartz>calcite>*** the other hand,it is found that a lower displacement velocity can benefit the miscibility process between alkane and CO_(2),which is conducive to the overall displacement process of CO_(2).The displacement efficiency can significantly decrease with the increase in displacement *** once the displacement velocity is very high,the strong driving force can promote the alkane to move forward,and the displacement efficiency will recover *** study further reveals the microscopic oil displacement mechanism of CO_(2) in shale nanopores,which is of great significance for the effective development of shale oil reservoirs by using the method of CO_(2) in

关键词： Displacement behavior Nanopores NEMD simulation Shale oil CO_(2) Kerogen

Teleportation for an Unknown Entangled State Without Any Joint Measurement via Josephson Charge Qubits

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第5期49卷 1195-1198页

作者： LI Da-Chuang ZHENG xiao-hu dong Ping CAO Zhuo-Liang Key Laboratory of Opto-electronic Information Acquisition and Manipulation Ministry of Education School of Physics＆ Material Science Anhui University Hefei 230039 China

An experimentally feasible scheme for teleportation of an arbitrary unknown entangled state is proposed. Our scheme is based on Josephson charge qubits, where we do not need any joint measurement. Moreover the successful probability and fidelity of the teleportation can both reach 1.0. The current scheme can be realized within the current experimental technology.

关键词： quantum teleportation Bell-state measurement Josephson charge qubits

Risk Models for the Prize Collecting Steiner Tree Problems with Interval Data

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2014年第1期30卷 1-26页

作者： Eduardo lvarez-Miranda Alfredo Candia-Vjar Xu-jin CHEN xiao-dong hu Bi LI Industrial Management Department Universidad de TalcaChile DEI University of BolognaItaly Academy of Mathematics and Systems Science CAS

Given a connected graph G=（V,E）with a nonnegative cost on each edge in E,a nonnegative prize at each vertex in V,and a target set V′V,the Prize Collecting Steiner Tree（PCST）problem is to find a tree T in G interconnecting all vertices of V′such that the total cost on edges in T minus the total prize at vertices in T is *** PCST problem appears frequently in practice of operations *** the problem is NP-hard in general,it is polynomial-time solvable when graphs G are restricted to series-parallel *** this paper,we study the PCST problem with interval costs and prizes,where edge e could be included in T by paying cost xe∈[c e,c＋e]while taking risk（c＋e xe）/（c＋e c e）of malfunction at e,and vertex v could be asked for giving a prize yv∈[p v,p＋v]for its inclusion in T while taking risk（yv p v）/（p＋v p v）of refusal by *** establish two risk models for the PCST problem with interval *** given budget upper bound on constructing tree T,one model aims at minimizing the maximum risk over edges and vertices in T and the other aims at minimizing the sum of risks over edges and vertices in *** propose strongly polynomial-time algorithms solving these problems on series-parallel graphs to *** study shows that the risk models proposed have advantages over the existing robust optimization model,which often yields NP-hard problems even if the original optimization problems are polynomial-time solvable.

关键词： uncertainty modeling prize collecting Steiner tree interval data series-parallel graphs polynomial-time solvability

Influence of Hot Press Forming Techniques on Properties of Vehicle High Strength Steels

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第5期18卷 59-63页

作者： CHANG Ying MENG Zhao-huan YING Liang LI xiao-dong MA Ning hu Ping School of Automotive Engineering State Key Laboratory of Structural Analysis for Industrial EquipmentDalian University of TechnologyDalian 116024LiaoningChina

Based on the combination of materials science and mechanical engineering,hot press forming process of the vehicle high strength steels was analyzed. The hot forming process included：heating alloys rapidly to austenite microstructures,stamping and cooling timely,maintaining pressure and quenching. The results showed that most of austenite microstructure was changed into uniform martensite by the hot press forming while the samples were heated at 900 ℃ and quenched. The optimal tensile strength and yield strength were up to 1530 MPa and 1000 MPa,respectively,and the shape deformation reached about 23%. And springback defect did not happen in the samples.

关键词： high strength steel lightweight hot forming martensite

Numerical simulation on the multiple planar fracture propagation with perforation plugging in horizontal wells

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2022年第5期19卷 2253-2267页

作者： Ming-hui Li Fu-Jian Zhou Bo Wang xiao-dong hu Dao-Bing Wang xiao-Ying Zhuang Shao-Bo Han Guo-Peng huang State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum-BeijingBeijing102249China Unconventional Oil and Gas Research Institute China University of Petroleum-BeijingBeijing102249China Institute of Photonics Leibniz Universitat HannoverHannover30167Germany Petroleum College China University of Petroleum-Beijing at KaramayXinjiang834000China Beijing Institute of Petrochemical Technology Beijing102240China

Intra-stage multi-cluster temporary plugging and diverting fracturing(ITPF)is one of the fastest-growing techniques to obtain uniform reservoir stimulation in shale gas ***,propagation geometries of multiple fractures during ITPF are not clear due that the existing numerical models cannot capture the effects of perforation *** this paper,a new three-dimensional FEM based on CZM was developed to investigate multiple planar fracture propagation considering perforation plugging during ***,the fluid pipe element and its subroutine were first developed to realize the flux partitioning before or after perforation *** results showed that the perforation plugging changed the original distribution of the number of perforations in each fracture,thus changing the flux partitioning after perforation plugging,which could eliminate the effect of stress interference between multiple fractures and promote a uniform fluid *** standard deviation of fluid distribution in the perforation plugging case was only 8.48%of that in the non-diversion ***,critical plugging parameters have been investigated ***,injecting more diverters will create a higher fluid pressure rise in the wellbore,which will increase the risk of wellbore *** considering pressure rise and fluid distribution,the number of diverters should be 50%of the total number of perforations(N_(pt)),whose standard deviation of fluid distribution of multiple fractures was lower than those in the cases of injecting 10%N_(pt),30%N_(pt)and 70%N_(pt).The diverters should be injected at an appropriate timing,i.e.40%or 50%of the total fracturing time(tft),whose standard deviation of the fluid distribution was only about 20%of standard deviations in the cases of injecting at20%tftor 70%tft.A single injection with all diverters can maintain high bottom-hole pressure for a longer period and promote a more uniform fluid distribu

关键词： Hydraulic fracturing Multi-cluster fracture propagation Perforation plugging Finite element method Fluid distribution

Bariatric surgery and diabetes:Current challenges and perspectives

在线全文

学校读者我要写书评

暂无评论

World Journal of Diabetes 2024年第8期15卷 1692-1703页

作者： Yan-Fei He xiao-dong hu Jun-Qiang Liu hu-Ming Li Shuang-Feng Lu Health Management Center The Sixth Medical CenterChinese PLA General HospitalBeijing 100048China Department of Endocrinology The Sixth Medical CenterChinese PLA General HospitalBeijing 100048China Department of Thoracic Surgery The Sixth Medical CenterChinese PLA General HospitalBeijing 100048China Department of Respiratory Medicine The Sixth Medical CenterChinese PLA General HospitalBeijing 100048China

Diabetes mellitus(DM)and obesity have become public issues of global *** surgery for the treatment of obesity combined with type 2 DM has been shown to be a safe and effective approach;however,there are limited studies that have systematically addressed the challenges of surgical treatment of obesity combined with *** this review,we summarize and answer the most pressing questions in the field of surgical treatment of obesity-associated DM.I believe that our insights will be of great help to clinicians in their daily practice.

关键词： Bariatric surgery Diabetes mellitus Obesity Metabolic surgery Challenge

Coefficients of earth pressure at rest in thick and deep soils

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Mining Science and Technology 2009年第2期19卷 252-255页

作者： TIAN Qiu-hong XU Zhi-wei ZHOU Guo-qing ZHAO xiao-dong hu Kun State Key Laboratory for Geomechanics ＆ Deep Underground Engineering School of Architecture and Civil Engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

The effect of test methods and stress paths on the experimental value of the coefficient of earth pressure at rest, K0, was investigated under high pressures. The results indicate that the rigid pressure chamber and flexible lateral confining pressure medium method gives a stress ratio at the initial stage that is not the real K0. Moreover, K0 increases during the loading process becoming greater at high pressures. In the unloading process, however, K0 increases only at the initial stage but decreases thereafter. In addition, the incremental magnitude definition, K0=dσ3/dσ1, gives higher values than the total magnitude definition, K0=σ3/σ1, under loading. This is also true during initial stages of unloading. The experiment results also indicate that earth pressure at rest in deep and thick soils can be estimated by a power function of axial and confining pressures. It is necessary to choose the appropriate Kn to avoid some accidents.

关键词： experimental research earth pressure at rest loading and unloading paths thick and deep soils