An Optimization Approach of IoD Deployment for Optimal Coverage Based on Radio Frequency Model

Recently,Internet of Drones(IoD)has garnered significant attention due to its widespread applications.However,deploying IoD for area coverage poses numerous limitations and challenges.These include interference between neighboring drones,the need for directional antennas,and altitude restrictions for drones.These challenges necessitate the development of efficient solutions.This research paper presents a cooperative decision-making approach for an efficient IoDdeployment to address these challenges effectively.The primary objective of this study is to achieve an efficient IoDdeployment strategy thatmaximizes the coverage regionwhile minimizing interference between neighboring drones.In deployment problem,the interference increases as the number of deployed drones increases,resulting in bad quality of communication.On the other hand,deploying a few drones cannot satisfy the coverage demand.To accomplish this,an enhanced version of a concise population-based meta-heuristic algorithm,namely Improved Particle SwarmOptimization(IPSO),is applied.The objective function of IPSO is defined based on the coverage probability,which is primarily influenced by the characteristics of the antennas and drone altitude.A radio frequency(RF)model is derived to evaluate the coverage quality,considering both Line of Sight(LOS)and Non-Line of Sight(NLOS)down-link coverage probabilities for ground communication.It is assumed that each drone is equipped with a directional antenna to optimize coverage in a given region.Extensive simulations are conducted to assess the effectiveness of the proposed approach.Results demonstrate that the proposed method achieves maximum coverage with minimum transmission power.Furthermore,a comparison is made against Collaborative Visual Area Coverage Approach(CVACA),and a game-based approach in terms of coverage quality and convergence speed.The simulation results reveal that our approach outperforms both CVACA and the gamebased schemes in terms of coverage and convergence speed.Comparisons validate the superiority of our approach over existing methods.To assess the robustness of the proposed RFmodel,we have considered two distinct ranges of noise:range1 spanning from−120 to−90 dBm,and range2 spanning from−90 to−70 dBmfor different numbers of UAVs.In summary,this research presents a cooperative decision-making approach for efficient IoD deployment to address the challenges associatedwith area coverage and achieves an optimal coveragewithminimal interference.

Analysis of Sea Surface Temperature Cooling in Typhoon Events Passing the Kuroshio Current

The aim of this study is to investigate the sea surface temperature(SST) cooling as typhoons pass the Kuroshio Current.A numerical circulation model,denoted as the Stony Brook Parallel Ocean Model(sbPOM),was used to simulate the SST,which includes four wave-induced effect terms(i.e.,radiation stress,nonbreaking waves,Stokes drift,and breaking waves) simulated using the third-generation wave model,called WAVEWATCH-Ⅲ(WW3).The significant wave height(SWH) measurements from the Jason-2 altimeter were used to validate the WW3-simulated results,yielding a root mean square error(RMSE) of less than 0.50 m and a correlation coefficient(COR) of approximately 0.93.The water temperature measured from the Advanced Research and Global Observation Satellite was applied to validate the model simulation.Accordingly,the RMSE of the SST is 0.92℃ with a COR of approximately 0.99.As revealed in the sbPOM-simulated SST fields,a reduction in the SST at the Kuroshio Current region was observed as a typhoon passed,although the water temperature of the Kuroshio Current is relatively high.The variation of the SST is consistent with that of the current,whereas the maximum SST lagged behind the occurrence of the peak SWH.Moreover,the Stokes drift plays an important role in the SST cooling after analyzing four wave-induced terms in the background of the Kuroshio Current.The sensitivity experiment also showed that the accuracy of the water temperature was significantly reduced when including breaking waves,which play a negative role in the inside part of the ocean.The variation in the mean mixing layer depth(MLD) showed that a typhoon could enhance the mean MLD in the Kuroshio Current area in September and October,whereas a typhoon has little influence on the mean MLD in the Kuroshio Current area in May.Moreover,the mean MLD rapidly decreased with the weakening of the strong wind force and wave-induced effects when a typhoon crossed the Kuroshio Current.

Research on traffic congestion mechanism and countermeasures based on dynamic traffic assignment

Traffic congestion is widely distributed around a network. Generally, to analyze traffic congestion, static traffic capacity is adopted. But dynamic characteristics must be studied because congestion is a dynamic process. A Dynamic Traffic Assignment modeling fundamental combined with an urban congestion analysis method is studied in this paper. Three methods are based on congestion analysis, and the stochastic user optimal DTA models are especially considered. Correspondingly, a dynamic system optimal model is suggested for responding congestion countermeasures and an ideal user optimal model for predicted congestion countermeasure respectively.

Impact of Transport Network Changes on Tourism in Protected Areas: A Case Study of Ayubia National Park, Pakistan

The inflow caused by tourists in peak seasons exerts an uncontrollable pressure on the existing infrastructure. The Ayubia National Park in Pakistan faces traffic delays and capacity restraints on the connecting roads in peak season. The study focuses on the formulation of critical strategies by deploying amendments in the transport network. The methodology contains three parts: 1) a questionnaire was designed to inquire about several variables from the visitors;2) the second part was traffic count data collection and analysis. Based on the response collected, the impact of multiple strategies on the network was analyzed using TransCad;3) in the third part, the results obtained were shared with experts to gain their valuable opinions. It was observed that the time of the day based access restriction to heavy vehicles could lead to dropping the Volume to capacity ratio from 1.7 to 1.2. However, the experts were also of the view that network changes can enhance and improve the visitors’ experience.

Research on dynamic characteristics model test scheme for middle pylon of multi-pylon multi-span suspension bridges

Multi-pylon multi-span suspension bridge is a new type super flexible structure system, and the rigidity design of middle pylon is one of the main difficult technical issues. Due to the requirements of longitudinal rigidity, the structural form and the corresponding foundation type of middle pylon are different from those of the ordinary steel pylon, and the complicated dynamic characteristics make the calculation quite difficult. In this article, exploration has been made in selection of similarity ratio and model materials, section simulation, restriction conditions simulation, fixing of mass blocks, fabrication scheme and testing method by taking into account different construction and working conditions such as restriction conditions and working environment of a three-pylon suspension bridge, to conduct the test experimental design of the dynamic behavior of the middle pylon, with the purpose to reveal its dynamic characteristics and make comparison and analysis with theoretical assumptions, to provide basis for anti-wind and anti-seismic design and reference for the design and research of three-pylon two-span suspension bridges in the future.

Energy-Efficient UAVs Coverage Path Planning Approach

Unmanned aerial vehicles(UAVs),commonly known as drones,have drawn significant consideration thanks to their agility,mobility,and flexibility features.They play a crucial role in modern reconnaissance,inspection,intelligence,and surveillance missions.Coverage path planning(CPP)which is one of the crucial aspects that determines an intelligent system’s quality seeks an optimal trajectory to fully cover the region of interest(ROI).However,the flight time of the UAV is limited due to a battery limitation and may not cover the whole region,especially in large region.Therefore,energy consumption is one of the most challenging issues that need to be optimized.In this paper,we propose an energy-efficient coverage path planning algorithm to solve the CPP problem.The objective is to generate a collision-free coverage path that minimizes the overall energy consumption and guarantees covering the whole region.To do so,the flight path is optimized and the number of turns is reduced to minimize the energy consumption.The proposed approach first decomposes the ROI into a set of cells depending on a UAV camera footprint.Then,the coverage path planning problem is formulated,where the exact solution is determined using the CPLEX solver.For small-scale problems,the CPLEX shows a better solution in a reasonable time.However,the CPLEX solver fails to generate the solution within a reasonable time for large-scale problems.Thus,to solve the model for large-scale problems,simulated annealing forCPP is developed.The results show that heuristic approaches yield a better solution for large-scale problems within amuch shorter execution time than the CPLEX solver.Finally,we compare the simulated annealing against the greedy algorithm.The results show that simulated annealing outperforms the greedy algorithm in generating better solution quality.

Field trial measurement and channel modeling for reconfigurable intelligent surface

With the advantage of programmable electromagnetic properties,Reconfigurable Intelligent Surfaces(RISs)havedrawn wide attention from both industry and academia.RIS-assisted communication systems can promote hugewireless channel quality improvement and remarkable coverage enhancement.This paper proposes generalpathloss model,radiation pattern and mirror beam effect of 1-bit RIS at sub-6 GHz band.Field trails have beencarried out in outdoor and indoor deployment scenarios.The proposed model is validated through extensivesimulations and field-trial measurements.In addition,an optimized RIS phase-shit design process for the mirrorbeam elimination is proposed and validated with simulations.The proposed theoretical model and measurementresults can promote future research and application in RIS-assisted communications.

L-Band Analysis of the Effects of Oil Slicks on Sea Wave Characteristics

The purpose of this study was to investigate the characteristics of sea surface waves as they pass through oil slicks.The parameterized first-guess spectrum method(PFSM)theory-based wave retrieval algorithm was applied to 20 images of horizontal-horizontal(HH)polarization obtained using the phased-array L-band synthetic aperture radar(SAR)(PALSAR)on the Advanced Land Observing Satellite(ALOS-1).The images were collocated with simulations from the WAVEWATCH-Ⅲ(WW3)model in a 0.1°grid using the European Centre for Medium-Range Weather Forecasts(ECMWF)reanalysis(ERA-5)winds data as the forcing field.The validation of the model-simulated significant wave height(SWH)against the measurements from the Jason-2 altimeter produced a 0.66m root mean square error(RMSE)for the SWH,with a coefficient(COR)0.74.In this sense,the WW3-simulated waves were reliable for our work.A comparison between the SAR retrieval results and the WW3 simulations was performed using the dataset for the regions without oil slicks,which produced a 0.34m RMSE for the SWH,with a COR of 0.79,which is less than a the RMSE of 0.52 m and the COR of 0.70 for the regions with oil slicks.Moreover,it was found that the SAR-derived SWHs were significantly underestimated by about 0.2m in the areas with oil slicks.This difference is probably due to the underestimation of the SAR-derived wind speeds at moderate wind speeds(i.e.,at wind speeds of greater than 5ms^(-1)).An additional analysis compared the SAR-derived wave spectra with those from the WW3 model as waves passed through the oil slicks.The interesting finding is that the wave energy at short wave lengths(about 30m)is reduced by the oil slicks,causing the movement of the dominant wave spectrum to shift to longer wave lengths(about 80 m).

Research on the Real-Time Dynamic Evaluation of Public Transport Passenger Service Satisfaction Based on the Internet

The current method of evaluating passenger satisfaction primarily adopts the traditional static evaluation mode,which can hardly satisfy the dynamic regulatory requirements of highway passenger transport service quality set by industry management departments.In this paper,we summarize the characteristics of real-time dynamic evaluation under the requirements of hierarchical and classified evaluation and analyze the entire process of the one-time travel service of highway passenger transport.We focus on station waiting and in-vehicle services,extract the elements most concerned by passengers as evaluation indexes,and construct a three-level index system.Subsequently,a multi-indicator comprehensive evaluation method based on the analytic hierarchy process and fuzzy comprehensive evaluation is selected to construct a comprehensive evaluation model.By combining with the development level of electronic ticket purchasing and the requirements of satisfaction evaluation,we propose three data collection methods and compare and analyze their strengths and weaknesses.Finally,based on actual survey data,the effectiveness of the model is verified.The verification results show that the real-time dynamic evaluation index system based on the Internet can better satisfy evaluation requirements.

Effects of Curing Methods on the Permeability and Mechanism of Cover Concrete

Curing methods are one of the most important factors in determining the quality and compactness of cover concrete.The effect of curing methods on the water absorption and sorptivity coefficient of cover concrete with the substitution ratio of fly ash(FA)and ground granulated blast slag(GGBS)for cement between 30 wt%and 40 wt%was studied by capillary water absorption test.The vacuum saturation test and mercury intrusion test were employed to characterize these differences in the pore structure of cover concrete under different curing methods.With further analysis of the compactness of microstructure by SEM,the mechanism of the impact of curing methods on the permeability of cover concrete was revealed.The results obtained indicate that the effect of curing methods on the water absorption,sorptivity coefficient and porosity of cover concrete shows the trend of natural curing>cover curing>water curing>standard curing.It is also shown that reasonable curing is advantageous to reduce the porosity and permeability of cover concrete.In natural curing conditions,the appearance of porosity increasing and pore structure coarsening is more critical for covering concrete with mineral admixtures than for pure cement concrete.Therefore,the permeability of cover concrete with mineral admixtures is more sensitive to the early-age curing methods.

公交车辆行车间隔可靠性评价方法(英文)

为了准确描述公交车辆运行可靠性、合理评价公共交通系统运营状况,提出了一种针对站点、线路、路网不同层面的公交可靠性改进计算方法.结合合肥市的公交实际运营数据,验证了所提出的可靠性定义对于传统方法的改进效果,并应用该方法分析了设置公交专用道后公交车辆运营可靠性的提升效果.研究表明,所提出的改进方法,可以克服传统可靠性评价方法的不足之处,例如间隔可靠性评价值会出现小于0和大于1的情况,且随着发车间隔的增大,计算的可靠性指标值呈现减小的趋势等.该方法可以更真实地反映公交系统运营状态,提高了公交车辆运行可靠性评价的合理性.

结合功能测试与模拟驾驶的老年人驾驶适性评估

为应对老年驾驶人驾驶能力下降带来的交通安全问题并降低与其相关的事故风险,建立了可有效替代道路驾驶测试的老年人驾驶适性评估方法.对92名老年驾驶人进行了功能测试、模拟驾驶测试与道路驾驶测试,通过独立样本T检验与分层逐步Logistic回归确定评价指标体系,分别建立并比选了决策树、随机森林和支持向量机3种评估模型.结果表明,以对比敏感度、功能性伸展、交通标志理解以及合流变道距离等作为评价指标的支持向量机模型对驾驶适性的评估效果最好,准确率高达84.6%.该方法可以有效替代道路测试评估老年人的驾驶适性,能为其停止驾驶、调整驾驶行为、训练提升驾驶能力、使用辅助驾驶技术等提供参考.

Dynamic finite element model updating of prestressed concrete continuous box-girder bridge

The dynamic finite element model （FEM） of a prestressed concrete continuous box-girder bridge, called the Tongyang Canal Bridge, is built and updated based on the results of ambient vibration testing （AVT） using a real-coded accelerating genetic algorithm （RAGA）. The objective functions are defined based on natural frequency and modal assurance criterion （MAC） metrics to evaluate the updated FEM. Two objective functions are defined to fully account for the relative errors and standard deviations of the natural frequencies and MAC between the AVT results and the updated FEM predictions. The dynamically updated FEM of the bridge can better represent its structural dynamics and serve as a baseline in long-term health monitoring, condition assessment and damage identification over the service life of the bridge .

Fiber-reinforced Mechanism and Mechanical Performance of Composite Fibers Reinforced Concrete

To understand the enhancing effect and fiber-reinforced mechanism of composite fibers reinforced cement concrete, the influences of composite fibers on micro-cracks and the distribution of composite fibers were evaluated by optical electron micrometer(OEM) and scanning electron microscope(SEM). Three kinds of fiber, such as polyacrylonitrile-based carbon fiber, basalt fiber, and glass fiber, were used in the composite fibers reinforced cement concrete. The composite fibers could form a stable structure in concrete after the liquid-phase coupling treatment, gas-liquid double-effect treatment, and inert atmosphere drying. The mechanical properties of composite fibers reinforced concrete(CFRC) were studied by universal test machine(UTM). Moreover, the effect of composite fibers on concrete was analyzed based on the toughness index and residual strength index. The results demonstrated that the composite fibers could improve the mechanical properties of concrete, while the excessive amount of composite fibers had an adverse effect on the mechanical properties of concrete. The composite fibers could significantly improve the toughness index of CFRC, and the increment rate is more than 30%. The composite fibers could form a mesh structure, which could promote the stability of concrete and guarantee the excellent mechanical properties.

基于旋转压实成型方法的乳化沥青冷再生混合料配合比设计（英文）

为了研究旋转压实成型方法在乳化沥青冷再生混合料中的应用,优化相关技术参数,利用劈裂强度试验、稳定度试验及水稳定性试验,通过改变旋转压实次数、乳化沥青用量、成型试件温度及拌合用水量等因素分析对体积参数、力学性能及水稳定性能的影响。研究结果表明:旋转压实方法能够有效提高乳化沥青冷再生混合料的最大干密度和干湿劈裂强度比指标、降低空隙率及最佳拌合用水量,且随着压实次数的增加,空隙率和劈裂强度指标呈指数函数关系变化。而干湿劈裂强度比指标与空隙率指标则符合二次函数关系。研究推荐采用经旋转压实70次,温度25°C制备的成型试件,依据干湿劈裂强度比指标确定最佳乳化沥青用量。汇总研究成果,旋转压实成型方法能够有效地在乳化沥青冷再生混合料配合比中应用。利用该方法能够显著提高路面高温稳定性能和抗水损害能力。通过对早期强度和路用性能评价,各项技术指标均高于规范。

Evaluation on Self-healing Mechanism and Hydrophobic Performance of Asphalt Modified by Siloxane and Polyurethane

In order to inhibit and remove the thin ice and extend the lifetime of the damaged bridge, the self-healing mechanism and hydrophobic performance of asphalt modified by siloxane and polyurethane (ASP) were studied by dynamic shear rheology (DSR), fluorescence microscope (FM), atomic force microscope (AFM), the fracture-healing-re-fracture test and molecular simulations. The experimental results indicated that the selfhealing capability of ASP increased with increasing heating time and temperature. Furthermore, the addition of siloxane could improve the reaction energy barrier and complex modulus, and it is believed that the self-healing is a viscosity driven process, consisting of two parts namely crack closure and properties recovery. Contact angle of ASP increased with the increasing siloxane content and it deduced that the siloxane could improve the hydrophobic performance of ASP and the ASP molecule model could simulate well the self-healing mechanism and hydrophobic performance of ASP.

Performance of fixed geosynthetic technique of GRPS embankment

增强 Geosynthetic 、支持堆积(GRPS ) 堤逐渐地在过去的十年在很多区域并且为大量工程被构造了。然而，许多劣势在 GRPS 堤(叫的 CT 堤) 的常规技术上通过很多应用被暴露，即，不堪忍受的解决和侧面的排水量，低 geosynthetic 效率，等等。鉴于这些劣势， GRPS 堤(叫的 FGT 堤) 的固定 geosynthetic 技术在这个工作被开发。在这个系统， geosynthetic 被钢酒吧支点和具体的固定的顶在堆积头上修理。涉及 FGT 堤的原则和构造技术第一被描述。然后，数字分析方法和二阶段的分析方法被用来分别地学习 FGT 堤的表演。FGT 堤能提供一种更好的改进技术在软地面上构造一个高堤，这被显示出。

Deformation behavior of high performance fiber reinforced cementitious composite prepared with asphalt emulsion

A novel engineered cementitious composite(ECC) was prepared with the complex binder of Portland cement and asphalt emulsion.By adjusting the amount of asphalt emulsion,different mixture proportions were adopted in experiments,including four-point bending test,compressive test,and scanning electric microscopy(SEM).The SEM observation was conducted to evaluate the contribution of polyvinyl alcohol(PVA) fiber and asphalt emulsion to the composite toughening mechanism.The tests results show that the most remarkable deflection-hardening behavior and saturated multiple cracking are achieved when the content of asphalt emulsion is 10%.However,excessive content of asphalt emulsion causes severe damages on the deformation behavior as well as loss in compressive strength of the mixture.SEM observation indicates that the influence of asphalt emulsion on the fiber/matrix interfacial property changes the dominant fiber failure type from rupture into pull-out mode,and thus causes beneficial effects for strain-hardening behavior.

Three-dimensional stability of landslides based on local safety factor

Unlike the limit equilibrium method(LEM), with which only the global safety factor of the landslide can be calculated, a local safety factor(LSF) method is proposed to evaluate the stability of different sections of a landslide in this paper. Based on three-dimensional(3D) numerical simulation results, the local safety factor is defined as the ratio of the shear strength of the soil at an element on the slip zone to the shear stress parallel to the sliding direction at that element. The global safety factor of the landslide is defined as the weighted average of all local safety factors based on the area of the slip surface. Some example analyses show that the results computed by the LSF method agree well with those calculated by the General Limit Equilibrium(GLE) method in two-dimensional(2D) models and the distribution of the LSF in the 3D slip zone is consistent with that indicated by the observed deformation pattern of an actual landslide in China.

LanePost:Lane-Based Optimal Routing Protocol for Delay-Tolerant Maritime Networks

Ship.to.ship, ship.to.shore radio links empowered by Wi Fi, Wi MAX etc have been recently exploited to build maritime multi.hop mesh networks to provide internet services to on.ship users. However, because of the mobility of the vessels/ships and the large inter.ship distances, nodes in the maritime network are frequently disconnected, forcing data communication in the maritime mesh networks to be opportunistic and delay.tolerant. In this paper, we present Lane Post, an optimization approach for maritime delay.tolerant routing protocol. We exploit the shipping lane information to predict the rendezvous opportunities of the ships to optimize the route selection in delay.tolerant routing. In particular, we show that when the shipping lane information is available, an opportunistic routing graph(ORG) for each ship can be constructed to predict its multi.hop data routing opportunities to the other ships or to the shore. Based on the ORG, we develop an optimal route protocol(i.e., Lane Post) for each ship to minimize its delay of multi.hop packet delivery via dynamic programming. We discussed the ways of collecting shipping lane information by centralized method or distributed method.The proposed Lane Post protocol was evaluated by ONE, an open.source delay.tolerant network simulator, which shows its dramatic performance improvement in terms of delay reduction compared to the state.of.the.art opportunistic routing protocols.