A two-step quantum secure direct communication protocol with hyperentanglement

We propose a two-step quantum secure direct communication （QSDC） protocol with hyperentanglement in both the spatial-mode and the polarization degrees of freedom of photon pairs which can in principle be produced with a beta barium borate crystal. The secret message can be encoded on the photon pairs with unitary operations in these two degrees of freedom independently. This QSDC protocol has a higher capacity than the original two-step QSDC protocol as each photon pair can carry 4 bits of information. Compared with the QSDC protocol based on hyperdense coding, this QSDC protocol has the immunity to Trojan horse attack strategies with the process for determining the number of the photons in each quantum signal as it is a one-way quantum communication protocol.

The Security Analysis of Two-Step Quantum Direct Communication Protocol in Collective-Rotation Noise Channel

To analyze the security of two-step quantum direct communication protocol （QDCP） by using Einstein-Podolsky Rosen pair proposed by Deng et al. [Phys. Rev. A 68 （2003）042317] in collective-rotation noise channel, an excellent model of noise analysis is proposed. In the security analysis, the method of the entropy theory is introduced, and is compared with QDCP, an error rate point Qo（M ： （Q0, 1.0）） is given. In different noise levels, if Eve wants to obtain the same amount of information, the error rate Q is distinguishable. The larger the noise level ~ is, the larger the error rate Q is. When the noise level ~ is lower than 11%, the high error rate is 0.153 without eavesdropping. Lastly, the security of the proposed protocol is discussed. It turns out that the quantum channel will be safe when Q 〈 0.153. Similarly, if error rate Q〉 0.153 = Q0, eavesdropping information I 〉 1, which means that there exist eavesdroppers in the quantum channel, and the quantum channel will not be safe anymore.

Two-Step Efficient Deterministic Secure Quantum Communication Using Three-Qubit W State

A two-step deterministic secure quantum communication （DSQC） scheme using blocks of three-qubit W state is proposed. In this scheme, the secret messages can be encoded by employing four two-particle unitary operations and directly decoded by utilizing the corresponding measurements in Bell basis or single-particle basis. Comparing with most previous DSQC protocols, the present scheme has a high total efficiency, which comes up to 50%. Apart from this, it has still the advantages of high capacity as each W state can carry two bits of secret information, and high intrinsic efficiency because almost all the instances are useful. Furthermore, the security of this communication can be ensured by the decoy particle checking technique and the two-step transmitting idea.

Influence of Clip Locations on Intraaneurysmal Flow Dynamics in Patient-specific Anterior Communicating Aneurysm Models with Different Aneurysmal Angle

To improve aneurysm treatment,this study examined the influence of clip locations on hemodynamic factors in patient-specific anterior communicating artery(ACoA)aneurysms with different aneurysmal angle.We proposed a simplified classification of ACoA aneurysms using aneurysmal angle,defined by the angle of pivot of the aneurysmal dome and the virtual two-dimensional plane created by both proximal A2 segments of anterior cerebral artery(ACA).ACoA aneurysms with three different aneurysmal angles,which are 15°,80°and 120°,were analyzed in our study.In this work,we obtained hemodynamics before and after clipping surgery with three clip locations based on clinical clipping strategies in three ACoA aneurysms with different aneurysm angles.Results showed that local high pressure occurs at impingement region of the ACoA aneurysm before clipping and new impingement region close to the clipping location after clipping treatment.For clipping the aneurysm with aneurysmal angle 15°and a wide neck,wall shear stress(WSS)distribution is more uniform when the clipping angle of two clips close to 180°comparing with other two angles.In addition,for clipping the aneurysm with aneurysmal angle 80°and 120°,local high pressure appears on new impingement region and high WSS distributes around the clipping location when the clip plane is normal to the direction of inflow of aneurysm from the dominance of A1 segment of ACA.Hence,we should avoid the impingement of inflow from the A1 segment and choose a favorable clipping location for the fastness of clip.The results of our study could preoperatively give a useful information to the decision of surgical plan.

Explicit Rate Based Transmission Control Scheme in Vehicle-to-lnfrastructure Communication Networks

In Vehicle-to-infrastructure(V2I)communication networks,mobile users are able to access Internet services,such as video streaming,digital map downloading,database access,online gaming,and even safety services like accident alarm,traffic condition broadcast,etc.,through fixed roadside units.However,the dynamics of communication environment and frequent changing topology critically challenge the design of an efficient transport layer protocol,which makes it difficult to guarantee diverse Quality of Service(QoS) requirements for various applications.In this paper,we present a novel transport layer scheme in infrastructure based vehicular networks,and aim to resolve some challenging issues such as source transfer rate adjustment,congestion avoidance,and fairness.By precisely detecting packet losses and identifying various causes of these losses(for example,link disconnection,channel error,packet collision,buffer overflow),the proposed scheme adopts different reacting mechanisms to deal with each of the losses.Moreover,it timely monitors the buffer size of the bottleneck Road-Side Unit(RSU),and dynamically makes transfer rate feedbacks to source nodes to avoid buffer overflow or vacancy.Finally,analysis and simulation results show that the proposed scheme not only successfully reduces packet losses because of buffer overflow and link disconnection but also improves the utilization efficiency of channel resource.

Applying the Dynamic Two-Step Method to Forecast Remaining Oil Distribution of Lower Series ,Xiaermen Oilfield

The distribution of remaining oil is often described qualitatively. The remaining oil distributed in the whole reservoir is calculated according to the characteristics of the space distribution of the saturation of remaining oil. Logging data are required to accomplish this. However, many such projects cannot be completed. Since the old study of remaining oil distribution could not be quantified efficiently, the ＂dynamic two-step method＂ is presented. Firstly, the water cut of every flow unit in one well at one time is calculated according to the comprehensive water cut of a single well at one time. Secondly, the remaining oil saturation of the flow unit of the well at one time is calculated based on the water cut of the flow unit at a given time. The results show that ＂dynamic two-step method＂ has characteristics of simplicity and convenience, and is especially suitable for the study of remaining oil distribution at high water-cut stage. The distribution of remaining oil presented banding and potato form, remaining oil was relatively concentrated in faultage neighborhood and imperfect well netting position, and the net thickness of the place was great. This proposal can provide an effective way to forecast remaining oil distribution and enhance oil recovery, especially applied at the high water-cut stage.

Instantaneous information propagation in free flow,synchronized flow,stop-and-go waves in a cellular automaton model

Recently, a number of efforts are underway to investigate inter-vehicle communications （IVC）. This paper studies the instantaneous information propagation behaviours based on IVC in three different tragic situations （free flow, synchronized flow and stop-and-go waves） in a cellular automaton model. It is shown that different behaviours appear in stop-and-go waves from those in free flow and synchronized flow. While the distribution of Multi-hop Communication Distance （MhCD） is either exponential or uniform in free flow and synchronized flow, the distribution of MhCD is either exponential or with a single peak in stop-and-go waves.

A two-stage short-term traffic flow prediction method based on AVL and AKNN techniques

Short-term traffic flow prediction is one of the essential issues in intelligent transportation systems(ITS). A new two-stage traffic flow prediction method named AKNN-AVL method is presented, which combines an advanced k-nearest neighbor(AKNN)method and balanced binary tree(AVL) data structure to improve the prediction accuracy. The AKNN method uses pattern recognition two times in the searching process, which considers the previous sequences of traffic flow to forecast the future traffic state. Clustering method and balanced binary tree technique are introduced to build case database to reduce the searching time. To illustrate the effects of these developments, the accuracies performance of AKNN-AVL method, k-nearest neighbor(KNN) method and the auto-regressive and moving average(ARMA) method are compared. These methods are calibrated and evaluated by the real-time data from a freeway traffic detector near North 3rd Ring Road in Beijing under both normal and incident traffic conditions.The comparisons show that the AKNN-AVL method with the optimal neighbor and pattern size outperforms both KNN method and ARMA method under both normal and incident traffic conditions. In addition, the combinations of clustering method and balanced binary tree technique to the prediction method can increase the searching speed and respond rapidly to case database fluctuations.

Numerical study of the turbulent flow around a circular pier

In practical problems, the variation of the free surface around a circular pier is severe. For the Fluent CFD, the multiphase flow models cannot be used together with the LES model to calculate the free surface. Present paper provides a two-step method which joints the 2D compressible ideal-gas equations and the LES model to calculate the 3D flow field with free surface around the pier. The effects of the free surface on the flow structures are studied in detail.

DFDVis:A Visual Analytics System for Understanding the Semantics of Data Flow Diagram

Data flow diagram(DFD),as a special kind of data,is a design artifact in both requirement analysis and structured analysis in software development.However,rigorous analysis of DFD requires a formal semantics.Formal representation of DFD and its formal semantics will help to reduce inconsistencies and confusion.The logical structure of DFD can be described using formalism of Calculus of Communicating System(CCS).With a finite number of states based on CCS,state space methods will help a lot in analysis and verification of the behavior of the systems.But the number of states of even a relatively small system is often very great that is called state explosion.In this paper,we present a visual system which combines Formal methods and visualization techniques so as to help the researchers to understand and analyze the system described by the DFD regardless of the problem of state explosion.

A quantum secure direct communication scheme based on intermediate-basis

Quantum secure direct communication(QSDC)is a method of communication that transmits secret information directly through a quantum channel.This paper proposes a two-step QSDC scheme based on intermediate-basis,in which the intermediate-basis Einstein–Podolsky–Rosen(EPR)pairs can assist to detect channel security and help encode information.Specifically,the intermediate-basis EPR pairs reduce the probability of Eve choosing the correct measurement basis in the first step,enhancing the security of the system.Moreover,they encode information together with information EPR pairs to improve the transmission efficiency in the second step.We consider the security of the protocol under coherent attack when Eve takes different dimensions of the auxiliary system.The simulation results show that intermediate-basis EPR pairs can lower the upper limit of the amount of information that Eve can steal in both attack scenarios.Therefore,the proposed protocol can ensure that the legitimate parties get more confidential information and improve the transmission efficiency.

Development and prospect of downhole monitoring and data transmission technology for separated zone water injection

This article outlines the development of downhole monitoring and data transmission technology for separated zone water injection in China.According to the development stages,the principles,operation processes,adaptability and application status of traditional downhole data acquisition method,cable communications and testing technology,cable-controlled downhole parameter real-time monitoring communication method and downhole wireless communication technology are introduced in detail.Problems and challenges of existing technologies in downhole monitoring and data transmission technology are pointed out.According to the production requirement,the future development direction of the downhole monitoring and data transmission technology for separated zone water injection is proposed.For the large number of wells adopting cable measuring and adjustment technology,the key is to realize the digitalization of downhole plug.For the key monitoring wells,cable-controlled communication technology needs to be improved,and downhole monitoring and data transmission technology based on composite coiled tubing needs to be developed to make the operation more convenient and reliable.For large-scale application in oil fields,downhole wireless communication technology should be developed to realize automation of measurement and adjustment.In line with ground mobile communication network,a digital communication network covering the control center,water distribution station and oil reservoir should be built quickly to provide technical support for the digitization of reservoir development.

A Neural Network Approach to Computing the Delay and Flow Assignment of Computer Communication Networks

in this poper, the delay cia computer communication network as the average end-to-end delay ofpackets in the network is studied. The problem of computing the minimum delay and flow assignment of acomputer network is a coinbinatorial-optimization one. Further analyses show that it can approximate to a quadratic programing problem. To solve the problem, a new network model featuring global con vergence is used. The simulation results demonstrate the new method is feasible and effective.

Dynamic Event-Triggered Scheduling and Platooning Control Co-Design for Automated Vehicles Over Vehicular Ad-Hoc Networks

This paper deals with the co-design problem of event-triggered communication scheduling and platooning control over vehicular ad-hoc networks(VANETs)subject to finite communication resource.First,a unified model is presented to describe the coordinated platoon behavior of leader-follower vehicles in the simultaneous presence of unknown external disturbances and an unknown leader control input.Under such a platoon model,the central aim is to achieve robust platoon formation tracking with desired inter-vehicle spacing and same velocities and accelerations guided by the leader,while attaining improved communication efficiency.Toward this aim,a novel bandwidth-aware dynamic event-triggered scheduling mechanism is developed.One salient feature of the scheduling mechanism is that the threshold parameter in the triggering law is dynamically adjusted over time based on both vehicular state variations and bandwidth status.Then,a sufficient condition for platoon control system stability and performance analysis as well as a co-design criterion of the admissible event-triggered platooning control law and the desired scheduling mechanism are derived.Finally,simulation results are provided to substantiate the effectiveness and merits of the proposed co-design approach for guaranteeing a trade-off between robust platooning control performance and communication efficiency.

A new coupled-map car-following model based on a transportation supernetwork framework

A new car-following model is proposed by considering information from a number of preceding vehicles with intervehicle communication. A supernetwork architecture is first described, which has two layers： a traffic network and a communication network. The two networks interact with and depend on each other. The error dynamic system around the steady state of the model is theoretically analyzed and some nonjam criteria are derived. A simple control signal is added to the model to analyze the criteria of suppressing traffic jams. The corresponding numerical simulations confirm the correctness of the theoretical analysis. Compared with previous studies concerning coupled map models, the controlled model proposed in this paper is more reasonable and also more effective in the sense that it takes into account the formation of traffic congestion.

BCL-3: A High Performance Basic Communication Protocol for Commodity Superserver DAWNING-3000

This paper introduces the design and implementation of BCL-3, a high per- formance low-level communication software running on a cluster of SMPs (CLUMPS) called DAWNING-3000. BCL-3 provides flexible and sufficient functionality to fulfill the commu- nication requirements of fundamental system software developed for DAWNING-3000 while guaranteeing security, scalability, and reliability. Important features of BCL-3 are presented in the paper, including special support for SMP and heterogeneous network environment, semi- user-level communication, reliable and ordered data transfer and scalable flow control. The performance evaluation of BCL-3 over Myrinet is also given.

A Partitioning Methodology That Optimizes the Communication Cost for Reconfigurable Computing Systems

This paper focuses on the design process for reconfigurable architecture. Our contribution focuses on introducing a new temporal partitioning algorithm. Our algorithm is based on typical mathematic flow to solve the temporal partitioning problem. This algorithm optimizes the transfer of data required between design partitions and the reconfiguration overhead. Results show that our algorithm considerably decreases the communication cost and the latency compared with other well known algorithms.

Higher-Order Interactions： Understanding the knowledge capacity of social groups using simplicial sets

A predominant benefit of social living is the ability to share knowledge that cannot be gained through the information an individual accumulates based on its personal experience alone. Traditional computational models have portrayed sharing knowledge through interactions among members of social groups via dyadic networks. Such models aim at understanding the percolation of information among individuals and groups to identify potential limitations to successful knowledge transfer. How- ever, because many real-world interactions are not solely pairwise, i.e., several group members may obtain information from one another simultaneously, it is necessary to understand more than dyadic communication and learning processes to capture their full complexity. We detail a modeling framework based on the simplicial set, a concept from algebraic topology, which allows elegant encapsulation of multi-agent interactions. Such a model system allows us to analyze how individual information within groups accumulates as the group＇s collective set of knowledge, which may be different than the simple union of individually contained information. Furthermore, the simplicial modeling approach we propose allows us to investigate how information accumulates via sub-group interactions, offering insight into complex aspects of multi-way communication systems. The fundamental change in modeling strategy we offer here allows us to move from portraying knowledge as a ＂token＂, passed from signaler to receiver, to portraying knowledge as a set of accumulating building blocks from which novel ideas can emerge. We provide an explanation of relevant mathematical concepts in a way that promotes accessibility to a general audience [Current Zoology 61 （1）： 114--127, 2015].

跨国流动中的社会交往与文化沟通——城市传播视角下的越南边民跨境生计研究

跨国生计和实践促成的流动,使越南边民成为边境城市文化的参与者。而在与中国人及当地社会生活展开交往互动的过程中,中越两国边民共同构筑起一个交叠着地理生态、经济市场等特征的新的社会文化空间。从城市传播的视角入手,将这种充满跨国文化和复杂网络的社会文化空间视为"可交往城市"。在这个空间中,越南边民不仅通过商业往来、职业选择等流动的方式融入当地社会,同时,更通过微信等社交媒体和国内国外社群保持线上的联络与沟通,从而将"可交往"更深入地延伸至网络空间。聚焦中越边境口岸城市越南边民的跨国流动,通过呈现流动中草根群体的城市生活与日常交往,分析因流动的空间、交通工具、职业、信息、社会关系编织和型构起来的新的城市网络,从而探讨越南边民与中国当地居民共同塑造出的"可流动性"。最终,探讨跨国流动如何成为一种塑造新的城市文化与空间的重要力量。

Safety benefit of cooperative control for heterogeneous traffic on-ramp merging

The safety of heterogeneous traffic is a vital topic in the oncoming era of autonomous vehicles(AVs).The cooperative vehicle infrastructure system(CVIS)is considered to improve heterogeneous traffic safety by connecting and controlling AVs cooperatively,and the connected AVs are so-called connected and automated vehicles(CAVs).However,the safety impact of cooperative control strategy on the heterogeneous traffic with CAVs and human-driving vehicles(HVs)has not been well investigated.In this paper,based on the traffic simulator SUMO,we designed a typical highway scenario of on-ramp merging and adopted a cooperative control method for CAVs.We then compared the safety performance for two different heterogeneous traffic systems,i.e.AV and HV,CAV and HV,respectively,to illustrate the safety benefits of the cooperative control strategy.We found that the safety performance of the CAV and HV traffic system does not always outperform that of AV and HV.With random departSpeed and higher arrival rate,the proposed cooperative control method would decrease the conflicts significantly whereas the penetration rate is over 80%.We further investigated the conflicts in terms of the leading and following vehicle types,and found that the risk of a AV/CAV followed by a HV is twice that of a HV followed by another HV.We also considered the safety effect of communication failure,and found that there is no significant impact until the packet loss probability is greater than 30%,while communication delay’s impact on safety can be ignored according to our experiments.