Modeling Morning Commute with Different Kinds of Activities Based on Bottleneck Model

Morning commute problem has always been concerned by researchers in transportation research field.For the bottleneck existing in the road network between home and school,this paper studies the household travel with different kinds of activities,i.e.,home-school-home trip and home-school-workplace trip.Individuals just send their children to school and then go home,which is named school travel.Individuals need to send their children to school firstly and then go to work,which is named household travel.Firstly,according to the proportions of two types of travelers and school-work start time difference,the possible equilibrium cases are solved and the conditions for the occurrence of each case are revealed.Different from the traditional bottleneck model with a unique equilibrium traffic pattern,the mixed travel case has six possible equilibrium traffic patterns.Secondly,the cost of traveler is analyzed for all possible equilibrium traffic patterns.Result shows that equilibrium trip costs of two types of travelers are more sensitive to the number of travelers in that class than the number in another class in all possible equilibrium cases.Finally,the influence of school-work start time difference on the total travel cost is discussed.Result shows that the total system travel cost can be reduced by appropriately adjusting the difference of school-work start time.

A cellular automaton model for a bridge traffic bottleneck

A cellular automaton （CA） model is proposed in this paper to analyze a bridge traffic bottleneck. The simulation results with this model show that there are several phase transitions in the traffic average density, velocity and flow for each lane under a periodic boundary condition. An unstable phase in the traffic average density and velocity for the upstream and downstream lanes of the bridge is shown in a range of initial traffic densities. The critical points of the phase transitions and the phenomenon of the unstable phase found in the simulation are also explained with the mean-field theory.

Combined bottleneck effect of on-ramp and bus stop in a cellular automaton model

The combined bottleneck effect is investigated by modeling traffic systems with an on-ramp and a nearby bus stop in a two-lane cellular automaton model. Two cases, i.e. the bus stop locates in the downstream section of the on-ramp and the bus stop locates in the upstream section of the on-ramp, are considered separately. The upstream flux and downstream flux of the main road, as well as the on-ramp flux are analysed in detail, with respect to the entering probabilities and the distance between the on-ramp and the bus stop. It is found that the combination of the two bottlenecks causes the capacity to drop off, because the vehicles entering the main road from the on-ramp would interweave with the stopping （pulling-out） buses in the downstream （upstream） case. The traffic conflict in the former case is much heavier than that in the latter, causing the downstream main road to be utilized inefficiently. This suggests that the bus stop should be set in the upstream section of the on-ramp to enhance the capacity. The fluxes both on the main road and on the on-ramp vary with the distance between the two bottlenecks in both cases. However, the effects of distance disappear gradually at large distances. These findings might give some guidance to traffic optimization and management.

基于变分信息瓶颈多任务算法的多领域文本分类

多领域文本分类存在领域差异和词汇差异,导致分类的准确性和泛化性低,传统方法无法取得很好的效果.针对上述问题,本文提出基于变分信息瓶颈多任务算法的多领域文本分类方法,将任务建模为从综合特征中提取任务专属特征的分层学习表示问题.首先基于信息瓶颈原理,将综合特征和任务专属特征之间存在的冗余信息建模为均值为零,方差为对角矩阵的加性噪声,通过重参数化方法让噪声参与模型训练;其次通过信息瓶颈的变分边界构建模型损失函数以限制模型的信息流动,从而将带有加性噪声的综合特征解耦为任务专属特征;最后通过解码器中的分类器处理任务专属特征得到文本分类结果.实验表明,该模型在FDU-MTL多领域文本分类数据集上的平均分类准确率达到92.17%,较多个对比模型有明显提升,且该模型具有更好的可解释性.

W基于家庭通勤行为分析的共享停车优化研究

共享停车是缓解早高峰城市中心区域车位紧张的有效手段。基于瓶颈理论构建汇流瓶颈路网下个人与家庭混合出行的均衡出行模型,考虑共享停车影响下的出行行为决策,在多停车场条件下分析家庭与个人的通勤行为,比较通学通勤时间差的不同对各类出行者的出行时间及出行成本的影响,并基于均衡模型对共享停车规模进行优化,分析交易成本对出行行为选择的影响。研究发现:在多停车位竞争的情况下,用户会产生更多的早到成本,当通学通勤时间差较大时可以延缓系统高峰期,扩大共享车位规模可以达到对系统的优化。故政府应合理设置通学通勤时间差,在考虑社会总成本的情况下制定相关政策对共享停车规模进行优化,对共享交易成本进行管理从而实现资源的合理利用。

科技成果转化瓶颈与突破研究

近年来,科技成果转化作为推动国家科技进步和经济发展的关键环节,受到了广泛关注。本研究基于深入剖析科技成果转化的现状,识别并分类影响其效率的多维瓶颈问题,包括技术、管理、政策等方面。文章进一步深化对瓶颈问题的理解,并结合理论和实践探讨一系列针对性的突破策略,旨为理论研究和实际操作提供有益参考,并推动科技成果更高效地转化应用,进而驱动经济持续健康发展。

“卡脖子”技术甄别模型构建及应用——以工业软件为例

[研究目的]科学精准地识别特定领域的“卡脖子”技术清单,可以为明确关键核心技术攻关方向,加快实现高水平科技自立自强提供决策依据。[研究方法]从“卡脖子”技术高价值、大差距、强垄断、难突破特征属性出发,结合专利表征技术方式,通过构建基于“V-G-M-B”框架的“关键核心技术筛选—技术差距测度—技术垄断识别—技术突破研判”四位一体定量甄别模型,有效识别特定领域“卡脖子”技术清单。[研究结论]以工业软件产业专利数据为样本,识别出我国在该领域18项严重“卡脖子”、2项一般“卡脖子”及1项轻微“卡脖子”技术清单,与目前工业软件产业技术发展现状相一致,验证了“卡脖子”技术定量甄别模型的科学性和实用性。

轻型注意力机制遥感影像多类别目标检测方法研究

针对常规遥感影像目标模型难以在低功耗硬件中部署运行的问题,提出一种轻型的遥感影像多类别目标检测模型。在模型特征提取网络不同层中分别使用了带有SE通道注意力模块的卷积核组与瓶颈结构的卷积核组进行特征提取,然后通过包含通道注意力的多尺度增强网络输出3个尺度的特征图参数进行最终检测。以RSOD、谷歌地球等作为数据源构建了数据集,并对其中的训练集进行了样本增强。试验结果表明,本文提出的模型能够对不同环境下的多类别目标实施快速精准测出,并且训练后模型占用内存较小,运行参数量低,能够部署在低功耗的硬件终端并对遥感影像中的目标实施快速精准检测。

Dynamic Prediction Method of Production Logistics Bottleneck Based on Bottleneck Index

In modern manufacturing pattern, there are many uncertain factors in the modern manufacturing process, such as changes of product attribute, changes of manufacturing resources＇ state, and so on, which cause production logistics bottleneck frequently shift, and make decisions of production planning and control based on formed bottleneck deviated from practical production process. Considering these factors, present researches mainly apply afterwards control to optimize production process to passively adapt to bottleneck changes If the direction of bottleneck shifting can be accurately forecasted, the transition from afterwards control of chasing bottleneck to beforehand control can be realized. Therefore, aiming at the phenomenon of production logistics bottleneck shifting under uncertain manufacturing circumstances, this paper starts off with dynamic property of capability and requirement and then builds the concepts of bottleneck degree and bottleneck index to describe dynamic bottleneck characteristic of production unit; taken production capability, production load and quality assurance capability into consideration, mathematical model of bottleneck index is established to measure bottleneck degree accurately, consequently, quantitative research on mechanism of production logistics shifting is achieved. Based on bottleneck index, the prediction model of production logistics bottleneck is founded to predict dynamic change of bottleneck accurately. Finally, an example of forecasting and monitoring the production logistics bottleneck in one manufacturing shop is given to testify the validation and practicability of the prediction method.

基于Bottleneck的目标检测网络模型加速研究

针对YOLOv5的网络结构能降低模型复杂度,并解决数据不均衡问题,根据YOLOv5的结构特点,采取5种Bottleneck的替代方案,即IBN层、融合IBN层、Tucker卷积层、SPBottleneck和SEGBottleneck。实验基于COCO数据集,实验结果表明与改进前的Bottleneck相比,所提的IBN层、Tucker卷积层以及SEGBottleneck对模型的复杂度都有明显降低。模型规模分别减小了24.5%、22.5%和20.0%,模型运行速度分别提升了3.0%、3.8%和1.5%。基于Traffic数据集数据不均衡实验的结果表明:空间不均衡问题可以通过引入Focal EIoU解决;选择合适超参数能够加速模型的收敛,解决类别不均衡问题。

Bottleneck effects on the bidirectional crowd dynamics

The bottleneck effect on bidirectional crowd dynamics is of great theoretical and practical significance, especially for the designing of corridors in public places, such as subway stations or airports. Based on the famous social force model, this paper investigates the bottleneck effects on the free flow dynamics and breakdown phenomenon under different scenarios, in which different corridor shapes and inflow ratios are considered simultaneously. Numerical simulation finds an interesting self-organization phenomenon in the bidirectional flow, a typical characteristic of such a phenomenon is called lane formation, and the existence of which is independent of the corridor＇s shape and inflow rate. However, the pattern of the lane formed by pedestrian flow is related to the corridor＇s shape, and the free flow efficiency has close relationship with the inflow rate. Specifically, breakdown phenomenon occurs when inflows from both sides of the corridor are large enough, which mostly originates from the bottleneck and then gradually spreads to the other regions. Simulation results further indicate that the leaving efficiency becomes low as breakdown occurs, and the degree of congestion is proportional to the magnitude of inflow. The findings presented in this paper match well with some of our daily observations, hence it is possible to use them to provide us with theoretical suggestions in design of infrastructures.

无人驾驶停车共乘缓解瓶颈拥堵研究

利用无人驾驶车辆利于共乘和自行停车的特点,提出了一种新的高效的通勤模式——无人驾驶停车共乘。首先,基于扩展的瓶颈模型,解析了该出行模式下瓶颈处通勤行为的均衡特征,建立了共乘率、停车收费与出行成本(包括瓶颈排队、工作延误、共乘隐私损失及共乘下车延误)之间的定量关系,给出了可诱导至系统最优的拥堵收费方案。然后,实施了数值实验,证明了模型的有效性,探究了模型中关键参数对出行费用的影响。最后,提供了该通勤模式可以应用的实际场景。解析和数值实验结果均表明,该通勤模式可缩短早高峰出行的持续时长,简化出行过程,从而大幅减少出行费用和换乘停车场规模,可为未来解决城市交通拥堵和市中心停车位缺乏等难题提供借鉴。

农村金融发展与农业经济增长:“门槛效应”还是“瓶颈效应”?

本文使用PLSTR模型在县级层面探究了农村金融发展与农业经济增长间的关联机制。研究发现:农村金融发展对农业经济增长的影响具有显著的门槛效应,当金融相关率低于门槛水平1.55时,金融发展对经济增长的影响体现为金融排斥,而当其跨越门槛值后,二者将呈协同发展态势;农村金融发展同样存在瓶颈效应,当金融相关率超过2.4后,效率将达到极限,此后金融扩张非但不能促进增长,反而还会增加金融风险;目前全国多数县级农村的金融发展已跨越门槛,呈现良好发展态势,但是部分县存在过度金融化的隐患,尚需进行平衡治理。

城市更新:已有进展、待破解难题及政策建议

随着经济发展水平提升、产业结构变迁以及城镇化进程的放缓,越来越多的城市正在由增量建设为主向存量提质为主转变。城市更新是新时期推动城市发展方式转变和人民城市建设的必然选择。但由于长期以来我国城市建设的各项政策和制度都围绕城市新建展开,城市更新仍以地方自发探索为主,实践中面临诸多体制机制瓶颈。建议顺应城市发展方式转变的要求,出台国家层面的城市更新指导意见,完善城市更新项目实施管理机制,健全城市更新协商共治和公众参与机制,创新城市更新投融资模式,有效有序实施城市更新行动。

Modified Shifting Bottleneck Heuristic for Scheduling Problems of Large-Scale Job Shops

A modified shifting bottleneck algorithm was proposed to solve scheduling problems of a large-scale job shop.Firstly,a new structured algorithm was employed for sub-problems so as to reduce the computational burden and suit for large-scale instances more effectively.The modified cycle avoidance method,incorporating with the disjunctive graph model and topological sort algorithm,was applied to guaranteeing the feasibility of solutions with considering delayed precedence constraints.Finally,simulation experiments were carried out to verify the feasibility and effectiveness of the modified method.The results demonstrate that the proposed algorithm can solve the large-scale job shop scheduling problems(JSSPs) within a reasonable period of time and obtaining satisfactory solutions simultaneously.

基于Y-shaped路网的早高峰拼车定价策略

针对交通资源配置有限导致的早高峰通勤拥堵问题,借鉴共享经济理论,引入拼车出行概念,充分考虑通勤者出行方式和Y-shaped路网特点,建立了基于通勤者出行效益的拼车定价模型.模型结合费用补偿机制,讨论了以平台利润最大化和系统负效用最小化为目标的拼车定价策略,并给出了定价策略有效的阈值条件.研究结果表明,当通勤者都参与到拼车服务中时,拼车平台利润和交通系统负效用在其相应拼车定价策略下均能达到最优值,并且以交通系统负效用最小化为目标的拼车定价策略能消除Y-shaped路网中瓶颈处的交通拥堵.

面向ADS-B信号辐射源个体识别的轻量化模型设计

针对辐射源个体识别高精确度、轻量化、实时性的现实应用需求,提出了面向广播式自动相关监测(ADS-B)信号辐射源个体识别的轻量化模型设计方法。根据信号数据特点进行解码处理,并对不均衡样本进行权重调节,改善样本质量;通过分组卷积获取不同维度的细微特征,与初始特征拼接,实现多维互补特征融合,并联同步进行提高识别效率。利用Ghost bottleneck结构实现网络模型压缩与跨层连接,在融合多维特征的同时节省计算资源。实验结果表明,本文算法结构精简,计算量低,识别率达到95.2%,并在不同容量的样本识别中效果稳定。本文算法较好地平衡了辐射源个体识别精确度、轻量化与高时效的需求。

城市轨道大型换乘站大客流拥堵缓解方法

以成都市轨道交通4条线路换乘站骡马市站为研究对象,通过站内客流流线分析,提出站内客流拥堵解决方案,为缓解城市轨道交通大型车站的客流拥堵问题提供参考。运用基于社会力模型算法的AnyLogic仿真软件构建城市轨道交通大型换乘站模型,基于Fruin服务水平评价标准,分析远期规划高峰时段的客流时空轨迹演变规律,辨识地铁站内客流集散瓶颈点。根据拥堵成因分析,提出3类地铁换乘站内客流瓶颈点,分别为流线交织瓶颈点、通行能力不足瓶颈点与混合瓶颈点。结合骡马市站站内设施设计,针对3类瓶颈点分别提出优化改进措施,研究结果表明,优化后的车站场景模型能大幅度缓解车站客流拥堵,提升车站服务水平。

高速公路改扩建工程周边路网交通瓶颈识别

为满足日益增加的交通需求和提高通行质量,同时保障高速公路区域路网和作业区的交通正常运行,有必要开展高速公路改扩建工程周边路网交通均衡诱导研究,对改扩建高速公路上过载的交通流量进行分流和转移。准确地识别高速公路周边路网的交通瓶颈路段,是进行高速公路改扩建工程周边路网交通均衡诱导的重要基础。在对国内某高速公路改扩建工程周边路网交通运行状况调研的基础上,耦合了速度-密度关系模型和服务水平法,构建了交通瓶颈识别模型。然后,基于所构建的交通瓶颈识别模型,结合周边路网的通行能力和不同时段的服务水平,对周边路网不同时段下的交通瓶颈路段进行识别。

双模式交通拥挤收费与按比例补贴联合策略设计

针对小汽车和地铁构成的双模式交通系统,提出将道路拥挤收费的收入按比例补贴给地铁用户的联合方法,以鼓励部分用户出行由小汽车向地铁转移,优化交通系统的出行结构。联合策略以固定需求无收费无补贴时的双模式均衡出行方式为基础,分析与补贴联合时统一收费、最优收费、阶梯收费的均衡出行方式,算例分析不同收费与按比例补贴策略对方式划分与成本的影响及其适用性,讨论关键参数对方式划分的敏感性。研究发现,实施统一收费时地铁用户的初始增长量最高,但在补贴时增长不及其他收费策略,适合作为短时调节措施;实施阶梯收费对地铁用户数量的影响与最优收费相差不大,且社会总成本低于统一收费,适合作为长期调节措施;统一收费策略时增加地铁补贴力度,个体和社会都受益;但最优收费和阶梯收费时,增加补贴力度仅对个体有利。