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11.
基于神经网络的部分预应力混凝土梁荷载-裂缝模型研究   总被引:3,自引:0,他引:3  
混凝土结构裂缝形成和发展的过程十分复杂,具有一定的随机性,难于用常规的方法进行建模。应用神经网络较强的函数映射能力和联想、记忆功能,对部分预应力混凝土梁的荷载-裂缝关系进行建模,通过试验数据进行验证,效果良好,证明应用神经网络来对部分预应力混凝土梁的荷载-裂缝关系进行建模是可行的。  相似文献   
12.
In September 2015, the United Nations (UN) officially adopted the 2030 Agenda for Sustainable Development together with 17 sustainable development goals (SDGs) (UN, 2016). The attainment of the SDGs requires a strong commitment by all UN Member States, not least by the Member States at the International Maritime Organization (IMO). This empirical research aims to identify the role and challenges of stakeholders at IMO, when implementing the UN’s 2030 Agenda in the international maritime transport domain using a grounded theory approach. This paper describes the methodology and the analytical process undertaken and presents the main findings based on empirical data. The results are presented as a set of six propositions. The first proposition presents the phenomena engulfing Member States at IMO stemming out from lack of knowledge and policy incoherency on the 2030 Agenda at national level. The other five propositions suggest how these challenges could potentially be best alleviated through an IMO-led strategy on sustainable development within the context of the 2030 Agenda, supported by an appropriate governance structure that sees the introduction of strategic actors for coordinating the implementation of the SDGs at national level. With the support of a Task Force, and by also making use of the IMO Member State Audit Scheme (IMSAS), to create more awareness and ownership, the strategic actors could work towards balancing the three dimensions of sustainable development—the economic, the environmental, and the social dimensions—which were found to be imbalanced in the international maritime transport domain.  相似文献   
13.
Demand for commercial air travel has been increasing over the years and recent forecasts indicate similar future trends. New aircraft with enhanced design features are being built and entering the airline service globally. These enhancements aim to ensure continued safety, efficiency, performance and prolonged life serviceability. However, these new enhancements often neglect the impact of the changing anthropometric characteristics of the passenger. Past studies have identified increasing trends in the average weight, height and other anthropometrical and biometrical measures of people at a global scale. However, many are limited to only exploring the ramifications primarily from the perspective of passenger experience. This paper highlights the importance of considering passengers’ anthropometric characteristics from a holistic perspective and identifies gaps for future research.  相似文献   
14.
The Mediterranean area plays a pivotal role within the definition and implementation of regional strategies for integrated coastal zone management (ICZM). Under the umbrella of the Regional Framework Operation BeachMed-e, a research project was carried out in five Mediterranean EU regions (East Macedonia and Thrace in Greece, Lazio, Liguria, and Emilia Romagna in Italy and Languedoc-Roussillon in France), in order to study the different approaches to ICZM that have been applied and also to test new approaches to these regions. The aim of this article is to present and discuss the results of the common surveys conducted in order to investigate the institutional stakeholders’ perception on ICZM in the five Mediterranean regions considered. The results are presented region by region, while comparisons are carried out among regions. Summarizing the results it can be stated that some differences and common problems affecting the coastal decision-makers of the five Mediterranean regions considered were identified. Particularly, stakeholders involved in coastal management generally perceived a lack of collaboration and a poor information exchange in all the regions, resulting sometimes in a lack of awareness on coastal erosion issues.  相似文献   
15.
Abstract

One approach to the management of coastal and marine areas is the establishment of protected areas (e.g., reserves, parks, sanctuaries). Under the general rubric of “marine reserves,”; this paper examines the Latin American experience with this strategy. A comprehensive table lists most, if not all, national or state declared parks or reserves. The table is organized by country. All Latin American nations have, to a varying extent, declared marine parks and protected areas. The authors review the sources or uses which have been “managed”; by marine reserves, the management approaches, uses, and problem which have been identified in achieving management objectives. The authors conclude with observations about the potential future utility of marine reserves as a management approach for areas and resources of the coastal and littoral zones of Latin America.  相似文献   
16.
This paper develops a comprehensive approach to the definition of transportation analysis zones (TAZ), and therein, presents a new methodology and algorithm for the definition of TAZ embedded in geographic information systems software, improves the base algorithm with several local algorithms, and comprehensively analyses the obtained results. The results obtained are then compared to these presently used in the transportation analysis process of the Lisbon Metropolitan Area. The proposed algorithm presents a new methodology for TAZ design based on a smoothed density surface of geocoded travel demand data. The algorithm aims to minimise the loss of information when moving from a continuous representation of the origin and destination of each trip to their discrete representations through zones, and focuses on the trade-off between the statistical precision, geographical error, and the percentage of intra-zonal trips of the resulting OD matrix. The results for the Lisbon Metropolitan Area case study suggest a significant improvement in OD matrix estimates compared to current transportation analysis practises based on administrative units.
Elisabete A. SilvaEmail:

Luis M. Martínez   is a Civil Engineer from the Instituto Superior Técnico, Technical University of Lisbon since 2004. After finishing his degree, he started his work as researcher in the CESUR (Civil Engineering & Architecture Department—Instituto Superior Técnico) where he has been working since. In 2006 he completed his Master Thesis at Instituto Superior Técnico on Traffic Analysis Zones modeling and started his PhD studies on the theme: Metropolitan Transportation Systems Financing Using the Value Capture Concept. José Manuel Viegas   is Full Professor of Transportation at the Civil Engineering & Architecture Department of the Instituto Superior Técnico, Technical University of Lisbon. He has worked extensively in Modeling, Innovation and Policy in several types of Transport Systems. He was founder and first Director General of Transportnet, a group of eight leading European Universities with Advanced Studies in Transportation, and currently leads the Portuguese side of the Transportation Systems area in the MIT—Portugal program. Elisabete A. Silva   is at the University of Cambridge (University Lecturer in Planning at the Department of Land Economy and a Fellow of Robinson College). With more than 100 contributions in peer review journals, books/books chapters, conference proceedings, and a research track record of approximately 16 years, (both at the public and private sector), her research interests are centred on the application of new technologies to spatial planning in particular city and metropolitan dynamic modelling through time.  相似文献   
17.
In transportation projects, uncertainty related to the difference between forecast and actual demand is of major interest for the decision-maker, as it can have a substantial influence on the viability of a project. This paper identifies and quantifies discrete choice model uncertainty, which is present in the model parameters and attributes, and determines its impact on risk taking for decision-making applied to a case study of the High-Speed Rail project in Portugal. The methodology includes bootstrapping for the parameter variation, a postulated triangular distribution for the mode-specific input and a probabilistic graphical model for the socio-economic input variation. In comparison to point estimates, the findings for mode shift results in a wider swing in the system, which constitutes valuable information for decision-makers. The methodology, findings and conclusions presented in this study can be generalized to projects involving similar models.  相似文献   
18.
我1979年居住于澳门的时候,由澳门政府官印局出版了一部名为<简述葡暹关系:1511-1900>的小册子,全书共28页.是根据存放在澳门历史档案馆的资料编成写的.全书分为五部份:(1)16世纪初的果亚:1510年;马六甲:1511年;澳门:1557年.(2)进一步接触:商人、传教士与17世纪时期暹逻王对澳门的借款.(3)葡人的衰落与18世纪接触的减少,贸易衰退.(4)19世纪旧有关系的复苏,不完全条约与葡人的厂房.(5)结语.  相似文献   
19.
设计的启发式算法从图的合并操作出发 ,降低了计算复杂度 ,从应用效果看接近最优的程度也较以往算法好  相似文献   
20.
The objective of this work is to formulate a structure of procedures to support projects to integrate neighborhoods in the area of influence of railway corridors and the urban facilities around each station. Based on the concept of centrality, formulated mathematically by graph theory and with the support of a geographic information system (GIS), we propose interventions aiming to create a more harmonious urban environment better in tune with sustainable mobility. We highlight the relevance of quantitative approaches in the study of urban concepts to foster integration between transportation and urban development, as well as the potential of their application in various Brazilian metropolises having commuter rail systems that are currently underutilized and in the process of revitalization.  相似文献   
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