Intelligent monitoring and digital maintenance technology for the health of transportation infrastructure have gradually become a focus in the current construction and operation and maintenance of transportation infrastructure. The technology and applications for intelligent monitoring of transportation infrastructure will gradually form a development trend of "intelligent perception + full spatiotemporal networking + low-power operation." This paper, aimed at the field of health monitoring for transportation infrastructure, analyzes the current status and development of low-power intelligent perception technology and its applications. It also conducts a demand analysis and key technical analysis for low-power intelligent perception services, proposes an application plan for a low-power intelligent monitoring system based on "5G+BeiDou,", and provides suggestions for long-term development.

The current work introduces a hybrid enhancement approach that incorporates rotation and partially filled metal foam, aiming to achieve a balance between the cost and thermal performance of the latent heat thermal energy storage (LHTES) system. Based on the user-defined functions and enthalpy-porosity method, the effects of the filling position, the number of porous fins, and rotational speed on the melting process are numerically examined. Besides, the response surface methodology (RSM) and economic evaluation index are introduced to optimize the filling ratios at different positions and comprehensively compare the thermal performance and system cost. The results indicate that the structure with metal foam arranged simultaneously near the inner tube, outer shell, and radial positions achieves the best thermal performance, effectively shortening the melting time by 54.65 %. At a rotational speed of 0.50 RPM, five porous fins are identified as the optimal choice. Compared to the basic case, the optimal structure determined by RSM achieves a 73.02 % reduction in melting time and a 276.22 % increase in thermal energy storage rate (TESR). Additionally, it has better economic feasibility and heat transfer enhancement per unit mass of metal foam. The hybrid enhancement measures proposed in this paper can enhance the thermal performance of latent heat thermal energy storage unit (LHTESU) at a low cost, which is conducive to the realization of efficient and low-carbon clean production.

The latent heat thermal energy storage (LHTES) technology based on solid-liquid phase change material (PCM) is of great significance for the efficient utilization of thermal energy. To address the issues of slow thermal response and non-uniform melting of the LHTES technology, a hybrid heat transfer enhancement method combined with finned metal foam and steady rotation is proposed in this work. An enthalpy-porosity model considering non-Darcy porous effects and mechanical rotation is established based on the local thermal equilibrium assumption and the fixed grid system. Four different structures (uniform metal foam, graded metal foam, finned metal foam with uniform porosity, and finned metal foam with graded porosity) are investigated firstly to identify the optimal structural arrangement under the same volume of PCM. Numerical results demonstrate that the LHTES units strengthened by the finned metal foam with graded porosity achieve the shortest melting time and largest thermal energy storage rate (TESR). The graded porous structure reduces thermal resistance, rotation enhances flow and heat transfer inside the container, and the fins expand the heat source area. Moreover, the effect of different fin types, graded porosities, and rotational speeds are further considered. The findings suggest that the increase of these three parameters does not correspond to better thermal performance; instead, there is an optimal value. Compared with the base case, the optimal configuration (fin length of 20 mm, fin width of 1.5 mm, porosity gradient of 2%, and rotational speed of 0.5 rpm) can shorten the melting time by 46.68%, increase the TESR and Nu by 74.06% and 69.02%, respectively. This paper validates the feasibility of the hybrid heat transfer enhancement method with finned metal foam and steady rotation, which can offer new insights into the engineering practice of the LHTES technology.

In this paper, a combined passive graded metal foam and active mechanical rotation strategy is proposed to simultaneously solve the problem of slow melting rate and non-uniform phase change problem of the latent heat thermal energy storage (LHTES) technology. The enthalpy-porosity method and fixed grid structure are employed to numerically investigate the effects of porosity range, the number of graded layers, and the rotational angular velocity. Moreover, the response surface method (RSM) is further selected to optimize the structural parameters and obtain the function of melting performance and various factors. The result shows that there is an optimal porosity range and the total melting time decreases first and then increases with the increase of porosity range. When the porosity range is 12% and the graded layer is three, it can shorten the melting time by 35.54% and increase the thermal energy storage rate (TESR) by 51.57%. In addition, the melting performance is gradually improved as the number of graded layers increases. The strengthening effect of graded metal foam with just four layers is close to that of the maximum layers considered in this paper. The trend of the influence of rotation speed on the melting performance of the LHTES unit is consistent with the porosity range, indicating the existence of the optimal rotational speed. The RSM optimization structure, with a 14.969% porosity range, 5-layer graded number, and 2.267 rpm rotational speed, shortens the melting time by 42.42% and increases the TESR by 62.75% compared with the stationary case with uniform metal foam. This work verifies the effectiveness of active rotation coupling with passive graded porous structures, which could provide a new strengthening approach to enhance LHTES.

The latent heat thermal energy storage (LHTES) technology based on solid-liquid phase change material (PCM) is characterized by high energy storage density, small volume change, and constant operation temperature, which is widely employed in waste heat recovery, solar thermal utilization, and equipment thermal management. This paper introduces active flipping and graded porous to strengthen natural convection and heat conduction to alleviate the issue of low thermal conductivity and non-uniform phase change of PCM. Based on the fixed grid system, the enthalpy-porosity method combined with time-dependent gravity and non-Darcy porous effect is employed to solve the solid-liquid phase change problem under different porosity gradients, dimensionless flipping times (t*), t *), and modified Ra (Ra*) Ra *) numbers. Furthermore, the effects of the Ra * on the optimal t * and porosity gradient are also discussed. The results show that the flipping method can significantly enhance flow and heat transfer within the container, improve temperature field uniformity, and increase the proportion of latent heat storage. With the increase of porosity gradient and t *, the melting time initially decreases and then increases and the optimal thermal performance is achieved at a 6 % porosity gradient and t * = 0.4. Compared to the uniform porous structure without flipping, it can shorten melting time by 49.37 % and improve thermal energy storage rate (TESR) by 76.23 %. Additionally, the optimal porosity gradient is 6 % under different Ra *, but the optimal t * decreases with the increase of Ra *. This paper explores the charging performance of the thermal energy storage system with the graded metal foam structure and active flip method, which can contribute to the study of heat transfer enhancement in LHTES technology.

This paper focuses on the strengthening study of the latent heat thermal energy storage (LHTES) unit and proposes a coupling strengthening method with non-uniform graded metal foam and active rotation. The non-uniform graded metal foams are employed to enhance heat conduction, and the rotation method is selected to make full use of natural convection. The solidification and melting behavior under the coupling effect of non-uniform metal foam and active rotation are numerically analyzed. The aluminum foam is partially concentrated and divided into two parts (concentrated part and diluted part) and is divided into the even-layered or uneven-layered porous structures according to the different regions area. Under the same volume of phase change material (PCM), the effects of layered forms (even-layered and uneven-layered approach), concentrated porosity, concentrated ratio, and rotational speed are performed. It can be concluded that the metal foam should concentrated near the inner tube and the uneven-layered structure can further improve the phase change heat transfer performance compared to the even-layered structure. Moreover, the thermal performance of the LHTES unit improves firstly and then decreases as the concentrated porosity, concentrated ratio, and rotational speed increase. The optimal values are obtained at 0.86 concentrated porosity, 0.3 concentrated ratio, and 0.5 rpm rotational speed. Compared with the static case with uniform metal foam, the melting time, solidification time, and total melting and solidification time can be significantly reduced by 40.30 %, 28.66 %, and 33.18 %, respectively. Similarly, the thermal energy storage rate can be correspondingly increased by 62.57 %, 40.82 %, and 54.11 %, respectively.

The construction of digital road holographic application system has become an important part in the construction and long-term operation of smart cities.It first analyzes the current development status of digital roads,analyzes the key capabilities of digital road holographic applications from three perspectives,and proposes an overall solution for digital road holographic business applications.Finally,from the long-term development of digital road holographic business applications,development strategies and suggestions are given.

在国家"双碳"背景下,经济贡献与能耗贡献占比均突出的工业园区的绿色转型成为经济发展的新关注点.建设工业"零碳"园区已成为当下工业园区绿色转型的重点任务.文章从建筑材料低碳化、能源结构清洁化、资源利用循环化、碳排管理集约化等四个方面分析工业"零碳"园区的发展趋势,并从顶层规划牵引、技术创新促进、数字平台监管、商业模式构建四个方面设计了工业"零碳"园区的建设路径,最后针对工业"零碳"园区的发展给出建议,助力工业园区绿色数字化转型高质量发展.

This manuscript aims to study the positioning requirements, build an understanding of the positioning framework for the C-V2X system, and provide specific technologies according to the requirements and environments. Cellular vehicle-to-everything (C-V2X) is critical in allowing safe, dependable, and efficient transportation services as the foundation for vehicles to communicate with each other and everything around them. Positioning is a key component of C-V2X, which involves determining the vehicle's absolute and relative positions in relation to other objects such as buildings, pedestrians, traffic signs, and other cars. This manuscript will deeply explore the feasibility of Highly Accurate positioning for the C-V2X system. In this manuscript, Key Performance Indicators (KPIs) for C-V2X positioning will be described at the beginning. Then positioning challenges and conventional positioning methods for C-V2X like GNSS/Cellular/Sensors will be reviewed. Afterward, UE-based/UE-assisted C-V2X positioning architectures, and a series of key positioning technologies such as sidelink positioning, data fusion and synchronization will be proposed. Lastly, some testing and typical application cases will be provided.

随着"东数西算"的提出,运营商作为网络算力支持的主要角色,在大型数据中心的建设上也需要考虑现代化产业发展的低碳要求,对大型数据中心进行端到端的系统级能效优化,降低数据中心能耗.文章根据现阶段大型数据中心低碳技术趋势和应用现状进行比对分析,探索合理有效的解决方案趋势,提出未来大型数据中心低碳解决方案的对策建议.

Intelligent highways are important practical scenarios in the application of modern intelligent transportation systems. The rapid development of 5G intelligent network technology provides important technical support for improving the travel efficiency of autonomous driving in intelligent transportation systems and reducing the risk of collisions. This paper introduces the technology of 5G intelligent network connection, discusses the integration application of intelligent highway scene and intelligent network connection technology, and finally predicts the future development trend of the intelligent transportation system.

Passive heat dissipation cooling technologies based on natural convection in open channels can effectively control the maximum temperature and improve the temperature homogeneity of 5G base stations, data centers and other equipment. In this paper, the flow and heat transfer of natural convection in an open-ended square channel with two suspending heat sources are studied through numerical simulation. The distributions of the temperature field and flow field in the channel with different horizontal distances and vertical altitude differenced of the heat sources are acquired via the finite element method (FEM)-based COMSOL Multiphysics. The changes in local temperature and the local Nusselt number are obtained. The relationships between the temperature field, flow field, and Nusselt number with respect to the geometric parameters of the heat sources are discussed. With different geometric parameters of the two suspending heat sources, the average surface temperature at the bottom is always lower than the top, while the average Nusselt number reaches maximum and minimum values at the bottom and top surfaces, respectively. As the horizontal distance increases, the maximum vertical airflow velocity decreases. The average surface temperature and local Nusselt number go through a V-shape and reverse V-shape tendency, respectively. The maximum temperature at the surface of the heat source is 397 K at a horizontal distance of 0.36 m. The local Nusselt number on the side of the heat source reaches its maximum at a horizontal distance of 0.28 m with an average value of 33.5. As the vertical altitude difference increases, the temperature difference between the heat sources increases from 0 K to 54 K, and the maximum vertical airflow velocity goes through a reverse V-shape tendency. The Nusselt number of the right heat source decreases to a certain value of about 20, while that of the left heat source goes through a fluctuating tendency. The results show that the best arrangement of the heat sources is a vertical altitude difference of 0 m and a horizontal distance of 0.28 m.

As a key entry point for constructing a smart city, 5G smart park is characterized by relatively single traffic elements and clear business requirements, which is conducive to the realization of 5G+C-V2X commercialization. 5G network can bring network access conditions of Enhanced Mobile Broadband, Ultra-Reliable and Low Latency Communications and Massive Machine Type Communication for traffic groups in the park. This paper firstly analyzes the characteristics of the 5G network and the actual demand of traffic groups in the smart park. On this basis, we propose an intelligent vehicle network system based on 5G+C-V2X, which can provide a variety of intelligent traffic innovation technologies and business demonstrations. This system can be used to provide vehicle-road-cloud-network intelligent transportation services in multiple scenarios during the Winter Olympics. This can be an opportunity to create industrial benchmark cases of 5G innovation business, which effectively lead the industrial innovation of intelligent vehicle networking and promote better and faster development of the global Internet of Vehicles industry.

Cellular vehicle-to-everything (C-V2X) is essential in enabling safe, reliable, and efficient transportation services. It serves as serve as the foundation for vehicles to communicate with each other and everything around them. One fundamental element in C-V2X is positioning, namely extracting the vehicle’s absolute and relative positions concerning other objects such as buildings, pedestrians, traffic signs, and other vehicles. However, its feasibility in enabling vehicular positioning has not been fully explored yet. In this paper, key performance indicators (KPIs) for C-V2X positioning have been described firstly. Then positioning challenges and conventional positioning methods for C-V2X are reviewed. Afterward, two user equipment (UE)-based and UE-assisted C-V2X positioning architectures are proposed, and key technologies are also described. Lastly, testing and typical application cases are provided.

URLLC其低时延高可靠的特性为智能网联业务的实现提供了强有力的支撑.首先简要概括URLLC技术研究的背景,随后针对URLLC实现的重点关键技术进行描述,最后给出基于URLLC技术的智能网联应用的网络架构和部署建议.

面向科技冬奥园区(首钢园区)在大型体育赛事期间的智慧出行需求,构建了一套基于5G+C-V2X的智慧园区出行解决方案,并就无人接驳摆渡、无人物流派送、无人清扫进行重点剖析.本方案将在首钢园区的冬奥会测试赛和正式比赛中正式应用.因园区环境相对封闭、出行环节和主体也相对简单、运营主体相对明确,因此本方案的落地应用可为智慧园区、智慧城市的交通出行提供一定的示范和参考.

智慧园区作为城市微单元,将成为5G时代新型智慧城市建设重要切入点.自动驾驶又是5G的典型应用,在国家政策对车联网大力推动及5G+C-V2X技术和自动驾驶技术快速发展的背景下,园区智慧出行因其交通主体相对单一、商业模式相对明确、将会成为最先实现5G+车联网商业化落地的场景之一.文章针对园区自动驾驶业务出行场景进行业务需求和性能需求分析,构建了一套基于5G+C-V2X的智慧园区自动驾驶业务解决方案.本方案在冬奥园区的示范应用可以为智慧园区、智慧城市的智慧交通建设提供一定的示范和参考.

智能网联汽车可以实现安全、舒适和高效的行驶.蜂窝车用无线通信(C-V2X)技术是实现智能网联业务的重要技术手段之一.全球多个标准组织都开展了包括C-V2X关键技术、网络架构和业务应用场景的研究.C-V2X与感知技术、移动边缘计算(MEC)和5G相融合,能够为实现智能网联业务提供强大的助力.C-V2X网络的部署采用"终端-网络-平台"的一体化架构.通过开展规模试验、试点部署积累经验,逐步实现大规模商用落地.C-V2X也面临着产品商用化推广、建设投资成本较高以及商业模式不清晰等挑战.