可重复使用航天器时间协同飞行轨迹优化

针对可重复使用航天器(RLV)时间协同飞行轨迹优化问题,提出了一种基于Radau伪谱法的轨迹优化方法。方法以再入飞行时间可知性、可控性为目标,使用Radau伪谱法对RLV的飞行时间进行预测,进而协调出多RLV的再入协同飞行时间,以此再入飞行时间为终端约束使用Radau伪谱法生成满足协同飞行要求的再入轨迹。仿真结果表明,上述轨迹优化方法可以得到满足时间协同约束、状态约束和控制约束的飞行轨迹,具有较高的稳定性和较快的求解速度。所提方法满足多架RLV时间协同再入飞行的需求,具有很强的实用价值。     

基于状态空间模型序号编码进化算法的航班优化调度

多跑道航班进离港优化调度是将某一时间窗内进离港航班看作一个整体，对进离港航班进行统一优化排序，属于典型的组合优化问题。求解组合优化问题时，采用序号编码比二进制编码和实数编码等方式更直接、更方便。本文提出一种基于状态空间模型序号编码进化算法（OSEA），通过构造状态进化矩阵等操作来实现变异算子的功能，简化了遗传操作，并研究其在航班进离港优化调度中的应用。仿真实验表明：OSEA算法与先到先服务（FCFS）航班排序相比，航班总延误损失降低32.88％，且运算速度更快。     

A conceptual solution to the aircraft gate assignment problem using 0, 1 linear programming

The U.S. commercial airline movement to “hub” operations has increased rapidly over the past several years. This trend will grow with the introduction of the Wayport concept. These giant “people exchange” facilities will feature multiple runways and massive concourses. While the Wayport developers may automate the ground movement of passengers, the sheer size of the facilities and the anticipated close scheduling of flights will confront the passenger with a problem of new dimension in getting from arrival gate to departure gate. One thing that could help alleviate the situation would be “sensible” assignment of flights to gates - sensible in that the assignment would take into account the communion of interest of the passengers. Other things being equal, the positioning of incoming flights should take into account the distribution of passengers among connecting flights. The larger the number of passengers arriving on flight X for destination A, the closer flight X should be positioned to the flight departing for A. This inquiry looks conceptually at this problem, reducing the distance passengers must walk from gate to gate. The criterion selected is minimization of the total passenger-distance travel for a given arrival-departure cycle. The problem can be conveniently cast as a 0,1 Linear Programming (LP) problem. The author discusses derivation of problem parameters and then solves several representative problems. A unique feature of the LP approach is the availability with the optimal solution of cost factors and assignments for suboptimal solutions. Minor changes in the input data do not require reworking the problem. Although the solution is characterized as conceptual, some ideas are given for practical use of the solution methodology in a dynamic airport environment.     

航班滑行路径规划和停机位分配联合优化

针对机场的航班滑行路径规划和停机位分配的联合优化调度问题,构建基于冲突回避的滑行道与停机位联合调度模型,并提出改进的自适应差分进化算法求解问题.以最小化航班的滑行时间和旅客转机的行走时间为优化目标,建立非线性混合整数规划联合调度模型.设计考虑了滑行冲突的路径规划算法,完成航班的滑行路径分配,并通过自适应动态调整差分进化...     

Analysing the factors that influence the Pareto frontier of a bi‐objective supply chain design problem

In this paper a bi‐objective multi‐product model for the design of a production/distribution supply chain logistic network with four echelons is considered. The proposed optimization model minimizes the total cost of the network (including the fixed cost to open facilities and the transportation costs between them) and the total CO₂ emissions. Five factors (network size, product complexity, cost variability, CO₂ emissions generation and over‐capacity) are considered for the experimental framework. The problem is solved using the ε‐constraint method and the resulting Pareto frontiers (PF) are characterized using five new metrics specifically developed for analysing how those factors affect the resulting optimal configurations. The results show that over‐capacity and product complexity are the two most influential factors regarding the characteristics of the PF, and that their effects are in the same direction: more complexity and capacity mean a wider set of optima alternatives, some close to the ideal point, and in general with a smaller number of links used.     

城市轨道交通车站序列瓶颈系统优化分析

针对城市轨道交通车站进站设施瓶颈疏解缺乏系统的定量分析、成本模糊的问题,提出车站瓶颈定量分析模型,并在此基础上提出一种新优化策略。首先,建立乘客进站流程图,基于串联和并联混合的排队网络构建系统优化模型;其次,在现有优化策略基础上提出一种新的控制优化策略——变更设施序列,即交换安检设备和自动检票闸机的物理顺序;最后选取上海莘庄地铁站并根据两种优化策略给出具体优化方案,进行仿真实验。3种优化方案均有效减少了乘客排队时间,但总成本差异很大。到达率一定时,与无优化方案相比,优化方案1增加1台安检设备,减少了92.5%的等待时间,总成本增加了3.2%;优化方案2交换安检设备和闸机顺序,减少了80.3%的等待时间,总成本下降了50.4%;而优化方案3即方案1和2的叠加,几乎完全消除了乘客排队等待时间,但总成本却增加29.6%。结果分析表明,该模型能够很好地模拟瓶颈疏解成本,新策略在降低总成本上明显优于传统策略。     

What the passenger contributes to passenger comfort

An individual's reaction to a vehicle environment depends not only on the physical inputs but also on the characteristics of the individual. Surveys of airline passengers were conducted on board regularly scheduled commuter flights. Sex of the respondent and attitude toward flying were found to have import nt influences on passenger comfort. Individual differences were also found regarding (1) perceptions of environmental variables, (2) the importance of factors as determinants of comfort, and (3) the ease of and frequency of performing activities in flight.     

Operational detection of contrails from NOAA-AVHRR-data

This paper describes a fully automated scheme that allows for the detection of contrails using the infrared channels of the Advanced Very High Resolution Radiometer (AVHRR). The presented algorithm is adjusted to have a low rate of misdetection in spite of the low contrail detection efficiency resulting from this tuning. A time-series and regional patterns of contrail cloudiness over Central and Western Europe are derived. Daily analysis of noon scenes in 1996 indicates that the average of daytime contrail coverage over Central Europe was 0.5% 0.25 with regional maxima of 1.2%. Comparing noon and midnight scenes shows that night-time contrail coverage, which is especially effective in greenhouse forcing, is approximately one-third of that of daytime.     

飞机指派问题优化模型及算法研究

为了提高航空企业飞机排班计划的自动化水平,分析了航空企业飞机排班计划编制流程,将这个复杂组合优化问题分解为3个组合优化问题,重点研究了其中的飞机指派优化问题,归纳了要考虑的主要约束条件,以优化理论为基础,针对飞机排班计划优化问题中的关键问题—飞机指派问题建立了飞机指派优化模型,模型考虑了飞机与航班之间在机型、飞行区域、客流量等条件上的匹配要求,并给出了模型约束条件的编码方法,同时根据大量实际生产数据给出相应的惩罚系数表。为求解模型,构造了一种自适应单亲遗传算法,算法选用了适合模型的遗传算子,采用动态调整遗传算子操作概率的方式加快优化速度。采用航空公司的实际航班数据进行仿真实例研究结果表明,该模型和算法切实可行。     

Event‐based allocation of airline check‐in counters: a simple dynamic optimization method supported by empirical data

This paper studies the real‐life problem of dynamically optimizing the number of airport check‐in counters to allocate for a single flight. The main feature of our work is the use of empirical data collected at the Singapore Changi Airport, which drives the dynamic optimization model of a parallel queues system. We propose an event‐based dynamic programming model that simplifies considerably the optimization analysis even for large‐scale problems with 700+ booked passengers. We investigate the following research questions: (a) For a particular flight, what is the optimal number of counters the system should open with and what is the corresponding optimal total cost? (b) Given the state of the system at any event epoch, should we open another counter or not and what is the optimal cost‐to‐go from this state? The empirical data we collected at the airport are used to test the assumptions, estimate the key parameters, and run the computational experiments. We apply our model to 14 flights at the Singapore Changi Airport and identify cases in which, depending on the cost parameters, the model advocates the use of either a dynamic or a static policy. Although the model concerns only an exclusive‐use system, it is flexible enough to apply to other configurations such as a common‐use system or a single‐queue, multicounter system.     

新舟60模拟机飞行指引系统实现

以新舟60飞机为模型,C 语言为开发工具,开发出一套完整可行的飞行指引(F/D)软件.用以替代Collins APS-85飞控计算机完成飞行指引功能,并成功地在飞行模拟机上通过测试且得到应用.具有成本低廉,稳定可靠的特点,能够满足飞行员训练的需要.     

珠三角地区多机场系统航班时刻的仿真优化

珠三角地区机场分布稠密、空域紧张、航班延误率高。为降低该地区的航班延误,提出以延误分层模型为优化目标,采用空域机场仿真模型SIMMOD对珠三角地区多机场系统仿真建模和有约束限制的并行扰动随机近似（Simultaneous Perturbation Stochastic Approximation,SPSA）优化算法相结合的方法,对珠三角地区多机场系统的航班时刻进行仿真优化研究。采用非光滑反馈对SPSA算法进行了改进。仿真结果表明采用这种仿真优化方法生成的新航班时刻,可有效降低总延误时间。研究对从整体上减少珠三角地区多机场系统的延误成本具有重要价值。     

基于A~*算法的机场滑行路径优化研究

研究机场场面航班的滑行路径分配和滑行冲突问题。针对目前滑行效率制约机场调度。滑行冲突影响飞行安全的状态,提出将安全间隔、滑行规则和冲突避免限制规则作为约束条件建立了滑行路径优化模型。采用了A*算法给出了问题的优化,在保证滑行道调度零冲突的前提下,缩小航班的总滑行时间,提高了滑行效率。以重庆江北国际机场为例,与管制员依据机场细则得到的路径相比,结果表明提出的滑行道调度模型和优化方法是可行的,在实现较优的滑行路径的基础上能智能的发现冲突、解决冲突,可为繁忙机场的机场调度提供了决策支持。     

复杂多约束条件下航班除冰延误机理及资源优化配置

针对机场除冰运行存在的除冰航班延误频发、除冰资源使用粗放的问题,提出了考虑航班延误机理的除冰资源优化配置方法.研究了多参数综合影响的除冰效率及航班动态随机环境下的除冰排队延误机理.分析了除冰运行过程的复杂多约束条件,构建了以最小化除冰液消耗、除冰车需求和除冰延误架次为目标的飞机除冰资源多目标优化配置模型.利用自适应网格多目标粒子群算法求解模型并提出了基于多属性决策优化的除冰资源优化配置方法.除冰资源优化配置后除冰液消耗量、除冰车需求量、除冰延误架次相较于优化前分别降低了13.9%,12.8%, 19.3%.该方法为机场除冰运行资源优化提供了新思路.     

Integrated aircraft-path assignment and robust schedule design with cruise speed control

Assignment of aircraft types, each having different seat capacity, operational expenses and availabilities, critically affects airlines’ overall cost. In this paper, we assign fleet types to paths by considering not only flight timing and passenger demand, as commonly done in the literature, but also operational expenses, such as fuel burn and carbon emission costs associated with adjusting the cruise speed to ensure the passenger connections. In response to flight time uncertainty due to the airport congestions, we allow minor adjustments on the flight departure times in addition to cruise speed control, thereby satisfying the passenger connections at a desired service level. We model the uncertainty in flight duration via a random variable arising in chance constraints to ensure the passenger connections. Nonlinear fuel and carbon emission cost functions, chance constraints and binary aircraft assignment decisions make the problem significantly more difficult. To handle them, we use mixed-integer second order cone programming. We compare the performance of a schedule generated by the proposed model to the published schedule for a major U.S. airline. On the average, there exists a 20% overall operational cost saving compared to the published schedule. To solve the large scale problems in a reasonable time, we also develop a two-stage algorithm, which decomposes the problem into planning stages such as aircraft-path assignment and robust schedule generation, and then solves them sequentially.     

Reducing airport gate blockage in passenger aviation: Models and analysis

Commercial flights are typically assigned to an arrival gate at their destination station (airport) prior to their departure from their origin station. Although the gate is scheduled to be available when the flight arrives, this is not always the case in practice. Due to variability in departure and flight times, the arriving flight might arrive early, the previous flight departing from the gate might depart late, or both. When a flight arrives at its scheduled gate but has to wait because the preceding aircraft is still occupying that gate, we refer to this as gate blockage. Gate blockage can have many negative impacts, including passenger delays, missed connections, and increased fuel burn. Our research is focused on incorporating the inherent stochasticity of the system into the planning process to reduce the prevalence and impact of gate blockage. Specifically, we formulate an optimization problem to assign flights to gates so as to minimize the expected impact of gate blockage. We use historical data to predict delay distributions and conduct experiments to assess both the computational tractability of our approach and its potential for improvement in solution quality over existing approaches.     

航班恢复问题的迭代局部搜索算法

在恶劣天气和机械故障等原因造成航班不能按照原计划执行时，航空公司需要采取相应的措施对航班进行恢复。本文基于经典的资源指派模型，综合考虑了调整时间、换机、联程拉直、取消航班和调机5种恢复策略，提出一种以最小化加权成本为优化目标的航班恢复模型，并设计一种迭代局部搜索算法。首先用构造-修复启发式方法构造可行解，然后从该初始解出发，在飞机路线对的邻域中进行局部搜索。当陷入局部最优后，对解进行扰动，然后从扰动后的解重新出发进行局部搜索。为了提高搜索效率，同时降低陷入局部最优解的概率，局部搜索过程采用模拟退火算法。实例结果表明，本文提出的模型及算法能够在短时间内对受到影响的大规模航班计划进行恢复。     

基于灵活编组的城轨车底运用计划及鲁棒客流控制策略

针对通勤客流需求的动态性、不均衡性和随机性等复杂特征,提出基于灵活编组的城轨车底运用计划及鲁棒客流控制策略两阶段随机规划模型.第1阶段为编组类型指派和车底运用计划优化模型,以极小化系统运营成本为目标;第2阶段为车站协同限流鲁棒优化模型,以极小化乘客等待时间为目标.通过线性化方法将原模型重构为可被CPLEX等优化软件直接求解的混合整数线性规划模型.算例结果表明,灵活编组模式在仅增加0.5%乘客等待时间的基础上,可降低约30.2%的系统运营费用,表明灵活编组方案在满足客流需求的同时可合理地降低运营费用.此外,所提出鲁棒客流控制策略能够避免传统鲁棒优化方法过于保守的问题,对于实际运营过程中随机客流需求具有较好的适应性.     

Optimal Strategies for Inventory Control Systems with a Convex Cost Function

Some controlled Markovian processes in discrete time in the context of optimization of inventory control systems are studied. Optimality of (s, S)-policies for the case of convex cost functions is proved using theorems on existence and uniqueness of a nonrandomized stationary optimal policy for Markovian processes with discrete time and a continuous control set for criteria characterizing mean costs per unit time and overestimated total costs and Bellman equations.     

Designing a cost-effective CO2 storage infrastructure using a GIS based linear optimization energy model

Large-scale deployment of carbon capture and storage needs a dedicated infrastructure. Planning and designing of this infrastructure require incorporation of both temporal and spatial aspects. In this study, a toolbox has been developed that integrates ArcGIS, a geographical information system with spatial and routing functions, and MARKAL, an energy bottom-up model based on linear optimization. Application of this toolbox led to blueprints of a CO₂ infrastructure in the Netherlands. The results show that in a scenario with 20% and 50% CO₂ emissions reduction targets compared to their 1990 level in respectively 2020 and 2050, an infrastructure of around 600 km of CO₂ trunklines may need to be built before 2020. Investment costs for the pipeline construction and the storage site development amount to around 720 m€ and 340 m€, respectively. The results also show the implication of policy choices such as allowing or prohibiting CO₂ storage onshore on CO₂ Capture and Storage (CCS) and infrastructure development. This paper illustrates how the ArcGIS/MARKAL-based toolbox can provide insights into a CCS infrastructure development, and support policy makers by giving concrete blueprints over time with respect to scale, pipeline trajectories, and deployment of individual storage sites.