Container Based Nomadic Vehicular Cloud Using Cell Transmission Model

Nomadic Vehicular Cloud(NVC)is envisaged in this work.The predo-minant aspects of NVC is,it moves along with the vehicle that initiates it and functions only with the resources of moving vehicles on the heavy traffic road without relying on any of the static infrastructure and NVC decides the initiation time of container migration using cell transmission model(CTM).Containers are used in the place of Virtual Machines(VM),as containers’features are very apt to NVC’s dynamic environment.The specifications of 5G NR V2X PC5 interface are applied to NVC,for the feature of not relying on the network coverage.Nowa-days,the peak traffic on the road and the bottlenecks due to it are inevitable,which are seen here as the benefits for VC in terms of resource availability and residual in-network time.The speed range of high-end vehicles poses the issue of dis-connectivity among VC participants,that results the container migration failure.As the entire VC participants are on the move,to maintain proximity of the containers hosted by them,estimating their movements plays a vital role.To infer the vehicle movements on the road stretch and initiate the container migration prior enough to avoid the migration failure due to vehicles dynamicity,this paper proposes to apply the CTM to the container based and 5G NR V2X enabled NVC.The simulation results show that there is a significant increase in the success rate of vehicular cloud in terms of successful container migrations.

A novel conditional cell transmission model for oversaturated arterials

The objective of this work is to develop a novel feature for traffic flow models, when traffic queues on two-way arterials periodically extend until then they block an upstream signal in oversaturated conditions. The new model, proposed as conditional cell transmission model （CCTM） has been developed with two improvements. First, cell transmission model （CTM） is expanded for two-way arterials by taking account of all diverging and merging activities at intersections. Second, a conditional cell is added to simulate periodic spillback and blockages at an intersection. The results of experiments for a multilane, two-way, three-signal sample network demonstrate that CCTM can accommodate various traffic demands and accurate representation of blockages at intersections. The delay of left turns is underestimated by 40 % in moderate conditions and by 58% in oversamrated condition when using the CTM rather than CCTM. Finally, the consistency between HCS 2000 and CCTM shows that CCTM is a reliable methodology of modeling traffic flow in oversaturated condition.

Sensitivity analysis of key input parameters in conditional cell transmission model for oversaturated arterials

A novel conditional cell transmission model （CCTM） is a potential simulation tool because it accommodates all traffic conditions from light condition to oversaturated condition. To test the performance of the CCTM, a series of experiments for sensitivity analysis were designed and performed for a multilane, two-way, three-signal sample network. Experiment 1 shows that the model is performed in a logical and expected manner with variations in traffic demand with time and direction. Experiment 2 shows when the possibility of the occurrence of a useful gap increases to 60% and 100%, the delays in left rams decrease by 5% and 15%, respectively. In Experiment 3, comparing the possibility of a conditional cell of 0 with 100%, delay of left turn and delay of the entire network were underestimated by 58% and 11%, respectively. Hence, sensitivity analysis demonstrates that by reflecting local drivers＇ behaviors properly, the CCTM provides an accurate representation of traffic flow in simulating oversaturated traffic conditions.

Cell transmission model based traffic signal timing in oversaturated conditions

In order to investigate enhancements to cell transmission model (CTM) as a tool for traffic signal timing in oversaturated conditions, randomly distributed saturation flow rates and arrival rates were used instead of constant values to simulate traffic flow movement, estimate the average delay of the network and search for an optimal traffic signal timing plan. A case study was given to demonstrate that the proposed methodology can capture unique phenomena in oversaturated conditions such as forward wave, spillback and lane entrance blockage. The results show that CTM underestimates travel time by 25% when compared to Simtraffic, while the enhanced CTM underestimates by only 3%. A second case study shows that a dynamic signal timing plan is superior to a fixed signal timing plan in the term of average delay.

Applying the maximum information principle to cell transmission model of traffic flow

This paper integrates the maximum information principle with the Cell Transmission Model （CTM） to formulate the velocity distribution evolution of vehicle traffic flow. The proposed discrete traffic kinetic model uses the cell transmission model to calculate the macroscopic variables of the vehicle transmission, and the maximum information principle to examine the velocity distribution in each cell. The velocity distribution based on maximum information principle is solved by the Lagrange multiplier method. The advantage of the proposed model is that it can simultaneously calculate the hydrodynamic variables and velocity distribution at the cell level. An example shows how the proposed model works. The proposed model is a hybrid traffic simulation model, which can be used to understand the self-organization phenomena in traffic flows and predict the traffic evolution.

Atomic mechanisms of hexagonal close-packed Ni nanocrystallization revealed by in situ liquid cell transmission electron microscopy

The fundamental understanding of the mechanism underlying the early stages of crystallization of hexagonal-close-packed(hcp)nanocrystals is crucial for their synthesis with desired properties,but it remains a significant challenge.Here,we report using in situ liquid cell transmission electron microscopy(TEM)to directly capture the dynamic nucleation process and track the real-time growth pathway of hcp Ni nanocrystals at the atomic scale.It is demonstrated that the growth of amorphous-phase-mediated hcp Ni nanocrystals is from the metal-rich liquid phases.In addition,the reshaped preatomic facet development of a single nanocrystal is also imaged.Theoretical calculations further identify the non-classical features of hcp Ni crystallization.These discoveries could enrich the nucleation and growth model theory and provide useful information for the rational design of synthesis pathways of hcp nanocrystals.

Piezoelectric pump with flexible venous valves for active cell transmission

The development of organ-on-a-chip systems demands high requirements for adequate micro-pump performance,which needs excellent performance and effective transport of active cells.In this study,we designed a piezoelectric pump with a flexible venous valve inspired by that of humans.Performance test of the proposed pump with deionized water as the transmission medium shows a maximum output flow rate of 14.95 mL/min when the input voltage is 100 V,and the pump can transfer aqueous solutions of glycerol with a viscosity of 10.8 mPa·s.Cell survival rate can reach 97.22%with a yeast cell culture solution as the transmission medium.A computational model of the electric-solid-liquid multi-physical field coupling of the piezoelectric pump with a flexible venous valve is established,and simulation results are consistent with experimental results.The proposed pump can help to construct the circulating organ-on-a-chip system,and the simple structure and portable application can enrich the design of microfluidic systems.In addition,the multi-physical field coupling computational model established for the proposed piezoelectric pump can provide an in-depth study of the characteristics of the flow field,facilitating the optimal design of the micro-pump and providing a reference for the further study of active cell transport in organ-on-a-chip systems.

Location Specific Cell Transmission Model for Freeway Traffic

This paper describes a location specific cell transmission model of freeway traffic based on the observed variability of fundamental diagrams both along and across freeway segments. This model extends the original cell transmission model （CTM） mechanism by defining various shapes of fundamental diagrams to reproduce more complex traffic phenomena, including capacity drops, lane-by-lane variations, nonho- mogeneous wave propagation velocities, and temporal lags. A field test on a Canadian freeway was used to demonstrate the validity of the location specific CTM. The simulated spatio-temporal evolutions of traffic flow show that the model can be used to describe the traffic dynamics near bottlenecks more precisely than the original model.

Influence range of emergency under special events based on CTM

To determine the dynamic influence range of emergencies under special events, the spacial and temporal characteristics of the traffic flow are studied by simulation based on the cell transmission model （CTM）. Based on the traffic management measures used under special events, a semi-dynamic assignment algorithm is proposed, which is combined with an algorithm for logit multi-path traffic assignment and the CTM. In a simple calculation network, the spacial and temporal characteristics of traffic flows which vary with different traffic management schemes are studied, and a method to obtain the influence range of emergency is proposed by computing the jam time of the intersections. By contrasting the average delay of each vehicle, the dissipation effect is studied under two different traffic management schemes. The example shows that the spatial and temporal variety of the traffic flow can be easily simulated and the influence range of emergency can be confirmed by the method based on the CTM. The proposed method provides a new idea for decision-making on traffic management under emergency under special events.

Optimization method for evacuation zone with network reconfiguration based on dynamic simulation

Abstract： With a determinate danger zone and evacuation demand caused by an emergency, an optimization method for the evacuation zone with network reconfiguration based on dynamic simulation is proposed. The method contains three modules. First, the network in the evacuation zone is optimized by a model with the integrated strategy of lane reversal and intersection conflict elimination. Secondly, the dynamic evacuation simulation model based on the cell transmission model is applied to simulate the dynamic propagation process of evacuated vehicles in the network in the evacuation zone. The evacuation time for all evacuated vehicles leaving the danger zone is obtained and the setting of the current evacuation zone is fed back. Thirdly, the arrival distributions of evacuated vehicles at critical intersections of the evacuation zone are also obtained to estimate the delay at critical intersection to determine whether the intersection should be taken as the critical intersection in the next iteration. The evacuation zone is expanded gradually through iteration, and the reasonable evacuation zone and the optimal evacuation network is confirmed. Based on the survey of the parking lot and urban street network around Nanjing Olympic Sports Center, the models and the iterative algorithm were applied to obtain the optimal plan of the evacuation zone with network reconfiguration in an evacuation situation to verify the validity of the proposed method.

A Dynamic Road Incident Information Delivery Strategy to Reduce Urban Traffic Congestion

Advanced information and communication technolo-gies can be used to facilitate traffic incident management.If an incident is detected and blocks a road link,in order to reduce the incident-induced traffic congestion,a dynamic strategy to deliver incident information to selected drivers and help them make detours in urban areas is proposed by this work.Time-dependent shortest path algorithms are used to generate a subnetwork where vehicles should receive such information.A simulation approach based on an extended cell transmission model is used to describe traffic flow in urban networks where path information and traffic flow at downstream road links are well modeled.Simulation results reveal the influences of some major parameters of an incident-induced congestion dissipation process such as the ratio of route-changing vehicles to the total vehicles,operation time interval of the proposed strategy,traffic density in the traffic network,and the scope of the area where traffic incident information is delivered.The results can be used to improve the state of the art in preventing urban road traffic congestion caused by incidents.

白花蛇舌草提取物体外抗肿瘤作用及机制研究

目的研究中药白花蛇舌草提取物对Bel-7402细胞抗肿瘤作用及其作用机制.方法采用MTT法和集落形成实验检测白花蛇舌草提取物对Bel-7402细胞生长的抑制作用;采用淋巴细胞转化实验检测白花蛇舌草提取物对小鼠脾脏T淋巴细胞增殖的刺激作用,并筛选出药物的安全剂量范围;采用透射电镜初步观察药物作用后Bel-7402细胞的形态变化.结果 1)MTT比色实验、集落形成实验的结果表明,白花蛇舌草提取物对Bel-7402细胞的生长具有明显的抑制作用,且这种作用是剂量依赖关系,IC50为1.6g/L;2)透射电镜观察表明,药物作用后的Bel-7402肿瘤细胞的体积变小,核分裂像显著减少,没有明显的凋亡现象;细胞核固缩,异染色质块状聚集浓染,线粒体变大变圆,基质变淡,线粒体嵴变短变少甚至消失,在极度肿胀时,线粒体转化为小空泡状结构,并有细胞膜破损现象.结论 1)白花蛇舌草提取物可能通过直接影响肿瘤细胞能量代谢,对Bel-7402细胞生长具有明显的抑制作用,且呈剂量依赖关系;2)白花蛇舌草提取物具有促进小鼠脾淋巴细胞增殖的作用.

小鼠胸腺基质细胞株MTEC_B的细胞学特性

用免疫组织化学和透射电镜技术对本室所建立的小鼠胸腺基质细胞株ＭＴＥＣ_Ｂ进行了细胞学鉴定。免疫组织化学观察显示：４０ｋＤ、４５ｋＤ角蛋白和波形蛋白呈现强阳性，５２ｋＤ，５４ｋＤ，５８ｋＤ角蛋白和Ｓ－１００蛋白呈现阴性。电镜下见到，具有桥粒和张力丝结构，含较多的囊泡和髓样体，发达的高尔基复合体和线粒体。另外ＭＴＥＣ_Ｂ还表现为酸性磷酸酶、碱性磷酸酶、非特异性酯酶弱阳性。据此我们认为ＭＴＥＣ_Ｂ为上皮细胞来源，又因其只表达低分子量的角蛋白，而在胸腺原位上，皮质上皮细胞也只表达低分子量的角蛋白，故ＭＴＥＣ_Ｂ可能为胸腺皮质上皮细胞。

地塞米松诱导红系细胞凋亡的观察

以ＦＶＡ病毒诱导ＢＡＬＢ／ｃ小鼠脾细胞形成的红系细胞（ｅｒｙｔｈｒｏｉｄｃｅｌ）为研究对象，在红系细胞凋亡抑制剂——红细胞生成素（ＥＰＯ）存在情况下，观察了地塞米松（Ｄｅｘ）对上述细胞凋亡的诱导作用。结果表明，在一定浓度范围内，随着Ｄｅｘ作用时间的延长，细胞逐步凋亡并出现特有的ＤＮＡ梯形（ＤＮＡｌａｄｄｅｒ），而且其ＤＮＡ断裂程度与Ｄｅｘ的作用浓度呈正相关。透射电镜的结果证实，经最适浓度（５×１０－５ｍｏｌ／Ｌ）Ｄｅｘ处理后，红系细胞出现核固缩，染色质凝聚，核周隙扩大，核破裂，胞浆近膜处出现空泡以及细胞破碎等程度不同的细胞凋亡特征。说明Ｄｅｘ可拮抗ＥＰＯ的作用。

Visualizing the crystallization of sodium chloride under supersaturated condition

Crystallization in supersaturated solution plays a fundamental role in a variety of natural and industrial processes.However,a thorough understanding of crystallization phenomena in supersaturated solution is still difficult because the real-time visualization of crystallization processes under supersaturated condition is a great challenge.Herein,an electron beam-induced crystallization method was carried out in in situ liquid cell transmission electron microscopy(TEM)to visualize the crystallization of NaCl under supersaturated condition in real time.Crucial steps and behaviors in the crystallization of NaCl were captured and clarified,including the growth of NaCl nanocrystals with different morphologies,the formation of initial crystalline seeds from amorphous ion clusters,and the non-equilibrium growth behaviors caused by uneven distribution of precursor ions.This study provides the real-time visualization of detailed nucleation and growth behaviors in NaCl crystallization and brings an ideal strategy for investigating crystallization phenomena under supersaturated condition.

A cell-based robust optimal coordinated control on urban arterial road

Process of optimizing coordinated control is divided into two stages. At the first stage, the study improves a robust optimal control model of single-point intersection to optimize cycle and split. At the second stage, the study combines all links with intersections of arterial road as a complete system, and applies cell transmission model to simulate traffic flow on urban signalized arterial road. We propose a coordinated control model based on the platform to optimize offset between adjacent intersections. Genetic algorithm is executed by MATLAB to solve the model. The performance evaluations show that the model not only effectively reduces average delay and stopping rate of vehicles on arterial road and largely enhances traffic capacity of arterial road, but also lowers the sensitivity of signal control for flow fluctuations.

In-situ liquid cell TEM investigation on assembly and symmetry transformation of Pt superlattice

Two dimensional(2D)nanocrystal functional superlattices with a well controlled structure are of significant importance in photonic,plasmonic and optoelectronic applications and have been well studied,but it remains challenging to understand the formation mechanism and development pathway of the superlattice.In this study,we employed in-situ liquid cell transmission electron microscopy to study the formation of 2D superlattice and its local phase transition from hexagonal-to-square nanocrystal ordering.When colloidal nanocrystals flowed in the solution,long-range ordered hexagonal superlattice could be formed either through shrinking and rearrangement of nanocrystal aggregates or via nanocrystal attachment.As the nanocrystals’shape transformed from truncated octahedral to cube,the local superlattice rearranged to square geometry.Moreover,our observations and quantitative analyses reveal that the phase transition from hexagonal to square mainly originates from the strong van der Waals interactions between the vertical(100)facets.The tracking of 2D cube superlattice formation in real-time could provide unique insights on the governing force of superlattice assembling and stabilization.

Precision of Radiation Chemistry Networks: Playing Jenga with Kinetic Models for Liquid-Phase Electron Microscopy

Liquid-phase transmission electron microscopy(LP-TEM)is a powerful tool to gain unique insights into dynamics at the nanoscale.The electron probe,however,can induce significant beam effects that often alter observed phenomena such as radiolysis of the aqueous phase.The magnitude of beam-induced radiolysis can be assessed by means of radiation chemistry simulations potentially enabling quantitative application of LP-TEM.Unfortunately,the computational cost of these simulations scales with the amount of reactants regarded.To minimize the computational cost,while maintaining accurate predictions,we optimize the parameter space for the solution chemistry of aqueous systems in general and for diluted HAuCl4 solutions in particular.Our results indicate that sparsened kinetic models can accurately describe steady-state formation during LP-TEM and provide a handy prerequisite for efficient multidimensional modeling.We emphasize that the demonstrated workflow can be easily generalized to any kinetic model involving multiple reaction pathways.

Urban traffic congestion propagation and bottleneck identification

Bottlenecks in urban traffic network are sticking points in restricting network collectivity traffic efficiency. To identify network bottlenecks effectively is a foundational work for improving network traffic condition and preventing traffic congestion. In this paper, a congestion propagation model of urban network traffic is proposed based on the cell transmission model （CTM）. The proposed model includes a link model, which describes flow propagation on links, and a node model, which represents link-to-link flow propagation. A new method of estimating average journey velocity （AJV） of both link and network is developed to identify network congestion bottlenecks. A numerical example is studied in Sioux Falls urban traffic network. The proposed model is employed in simulating network traffic propagation and congestion bottleneck identification under different traffic demands. The simulation results show that continual increase of traffic demand is an immediate factor in network congestion bottleneck emergence and increase as well as reducing network collectivity capability. Whether a particular link will become a bottleneck is mainly determined by its position in network, its traffic flow （attributed to different OD pairs） component, and network traffic demand.

Incident-based traffic congestion control strategy

Traffic incident happens frequently in urban traffic network and it affects normal operation of traffic system seriously so that study on incident-based congestion control strategies is very important. This study addresses the problem of the temporary vehicle movement bans design under incident-based traffic congestion situation. A bi-level programming model is proposed to formulate this problem. The upper level problem is to minimize the total travel cost in the view of traffic management agencies, and the lower level problem is to present travelers’ dynamic route choice behavior under temporary vehicle movement bans using the simulation of cell transmission model, then a genetic algorithm is employed to solve the proposed bi-level programming model. Computational results show that the temporary vehicle movement bans measure is able to alleviate the traffic network incident-based congestion effectively and improve system performance of traffic network.