摘要：Combining named data networking（NDN） and software-defined networking（SDN） has been considered as an important trend and attracted a lot of attention in recent years. Although much work has been carried out on the integration of NDN and SDN, the forwarding mechanism to solve the inherent problems caused by the flooding scheme and discard of interest packets in traditional NDN is not well considered. To fill this gap, by taking advantage of SDN, we design a novel forwarding mechanism in NDN architecture with distributed controllers, where routing decisions are made globally. Then we show how the forwarding mechanism is operated for interest and data packets. In addition, we propose a novel routing algorithm considering quality of service（QoS） applied in the proposed forwarding mechanism and carried out in controllers. We take both resource consumption and network load balancing into consideration and introduce a genetic algorithm（GA） to solve the QoS constrained routing problem using global network information. Simulation results are presented to demonstrate the performance of the proposed routing scheme.

摘要：Heterogeneous cellular networks(HCNs), by introducing caching capability, has been considered as a promising technique in 5 G era, which can bring contents closer to users to reduce the transmission delay, save scarce bandwidth resource. Although many works have been done for caching in HCNs, from an energy perspective, there still exists much space to develop a more energy-efficient system when considering the fact that the majority of base stations are under-utilized in the most of the time. Therefore, in this paper, by taking the activation mechanism for the base stations into account, we study a joint caching and activation mechanism design to further improve the energy efficiency, then we formulate the optimization problem as an Integer Linear Programming problem(ILP) to maximize the system energy saving. Due to the enormous computation complexity for finding the optimal solution, we introduced a Quantum-inspired Evolutionary Algorithm(QEA) to iteratively provide the global best solution. Numerical results show that our proposed algorithm presents an excellent performance, which is far better than the strategy of only considering caching without deactivation mechanism in the actual, normal situation. We also provide performance comparison amongour QEA, random sleeping algorithm and greedy algorithm, numerical results illustrate our introduced QEA performs best in accuracy and global optimality.

摘要：Information centric networking(ICN) is a new network architecture that is centred on accessing content. It aims to solve some of the problems associated with IP networks, increasing content distribution capability and improving users' experience. To analyse the requests' patterns and fully utilize the universal cached contents, a novel intelligent resources management system is proposed, which enables effi cient cache resource allocation in real time, based on changing user demand patterns. The system is composed of two parts. The fi rst part is a fi ne-grain traffi c estimation algorithm called Temporal Poisson traffi c prediction(TP2) that aims at analysing the traffi c pattern(or aggregated user requests' demands) for different contents. The second part is a collaborative cache placement algorithm that is based on traffic estimated by TP2. The experimental results show that TP2 has better performance than other comparable traffi c prediction algorithms and the proposed intelligent system can increase the utilization of cache resources and improve the network capacity.

摘要：Hydrogen,regarded as a promising energy carrier to alleviate the current energy crisis,can be generated from hydrogen evolution reaction(HER),whereas its efficiency is impeded by the activity of ***,effective strategies,such as strain and interfacial engineering,are imposed to tune the catalysis performance of novel two-dimensional(2D)phosphorus carbide(PC)layers using first-principle *** findings show that P site in pristine monolayer PC(ML-PC)exhibits higher HER performance than C ***,constructing bilayer PC sheet(BL-PC)can change the coordinate configuration of P atom to form 3-coordination-P atom(3-co-P)and 4-coordination-P atom(4-co-P),and the original activity of 3-co-P site is higher than the 4-co-P *** an external compressive strain is applied,the activity of the 4-co-P site is enhanced whereas the external strain can barely affect that of 3-co-P ***,the graphene substrate enhances the overall activity of the BL-PC because the graphene substrate optimizes the?GH*value of 4-co-P site,although it can barely affect the HER activity of 3-co-P site and *** desirable properties render 2 D PC-based material promising candidates for HER catalysts and shed light on the wide utilization in electrocatalysis.

摘要：The cooling control of the melt during the casting process is of great significance. A comprehensive closed-loop cooling control of castings by adopting a skeletal sand mold design was proposed. The skeletal sand mold consisting of an adaptive shell, functional cavities and a support was designed and created based on the finite difference meshes of a casting. It was applied to a round wall test casting. Two kinds of skeletal sand molds, one with lattice support and the other with enforcing ribs for this casting were designed and printed out by the 3 D printing(3 DP) method. Aluminum alloy A356 was cast by using these two sand molds. The first mold was cooled by natural convection, the other one by water spray cooling. Two sound castings were obtained. The sand mold temperature, cooling curves, microstructures, mechanical properties, residual stress and deformation were measured, compared and discussed. Water spray cooling hastened the cooling rate by 62%, increased the content of Mg and Cu in the α-Al matrix, improved the mechanical properties, and altered the surface residual stress state.

摘要：超临界水冷堆(SCWR)具有热效率高、结构简单等技术优势,是第四代核能系统国际论坛推荐的6个堆型之一。本文首先回顾了SCWR的包壳设计要求和主要性能挑战,然后对经过较多测试的商用候选包壳材料的均匀腐蚀、应力腐蚀及辐照性能进行了回顾。铁素体/马氏体(F/M)钢、奥氏体不锈钢及镍基合金均存在某方面的性能不足。最后,介绍了近年来新兴的SCWR候选包壳材料,包括新型含铝奥氏体不锈钢、氧化物弥散强化钢、梯度材料及其他组织改进技术的研究进展。

摘要：：In today＇s networks, load balancing and priority queues in switches are used to support various quality-of-service （QoS） features and provide preferential treatment to certain types of traffic. Traditionally, network operators use ‘traceroute＇ and ‘ping＇ to troubleshoot load balancing and QoS problems. However, these tools are not supported by the common OpenFlow-based switches in software-defined networking （SDN）. In addition, traceroute and ping have potential problems. Because load balancing mechanisms balance flows to different paths, it is impossible for these tools to send a single type of probe packet to find the forwarding paths of flows and measure latencies. Therefore, tracing flows＇ real forwarding paths is needed before measuring their latencies, and path tracing and latency measurement should be jointly considered. To this end, FlowTrace is proposed to find arbitrary flow paths and measure flow latencies in OpenFlow networks. FlowTrace collects all flow entries and calculates flow paths according to the collected flow entries. However, polling flow entries from switches will induce high overhead in the control plane of SDN. Therefore, a passive flow table collecting method with zero control plane overhead is proposed to address this problem. After finding flows＇ real forwarding paths, FlowTrace uses a new measurement method to measure the latencies of different flows. Results of experiments conducted in Mininet indicate that FlowTrace can correctly find flow paths and accurately measure the latencies of flows in different priority classes.

摘要：目前中国慢性病负担沉重,加快推进慢性病早期预防的研究迫在眉睫。大型人群队列是慢性病病因学研究的首要设计之一,有助于人们寻找到切实可行的慢性病干预措施。同时,从大型人群队列的基因水平阐明危险因素与疾病的遗传关联,也可开辟一条研究流行病学中因果关系的新途径。本文对由中国医学科学院、北京大学和英国牛津大学联合开展的“中国慢性病前瞻性研究”项目China Kadoorie Biobank(CKB)进行了推介,重点介绍了该项目遗传数据资源的建设进展以及近年来发表的遗传学研究成果,以期为我国大型人群队列遗传资源的深入挖掘与利用提供参考。

摘要：江西是农业大省,水资源禀赋优良,编制《江西省农田灌溉发展规划》对促进农业现代化、保障国家粮食安全具有重要意义。在系统分析全省灌溉发展现状和面临形势的基础上,全面分析水土资源状况和灌溉发展潜力,研究提出了未来全省灌溉发展总体布局、发展目标、建设和管理主要任务,可为未来一定时期内的全省灌区高质量发展提供指导。

摘要：文章研究了带饱和现象的T-S离散时间模糊系统.建立了T-S模糊系统,并对该系统进行稳定性分析,利用PDC技术、二次Lyapunov函数以及线性矩阵不等式(LMI)方法,建立了闭环模糊系统渐近稳定的判别条件.通过求解LMIs,给出了相应的模糊控制律的设计方法.并得到闭环模糊系统的吸引域.