光伏用电致发光缺陷检测仪空间分辨率的量化评估

针对光伏用电致发光缺陷检测仪空间分辨率目视判定重复性、准确性差,并且难以量化等问题,提出一套基于卷积神经网络模型的空间分辨率量化评估方法。参照相关标准JJF(闽)1088-2018,采取不同的拍摄条件拍摄并切割出空间分辨率线对图像,对图像进行人工分类。设计卷积神经网络结构,采用卷积层、池化层和全连接层结构,并使用已分类完成的空间分辨率线对图像对模型进行训练。最终使用测试集对模型进行评估,结果表明,模型在测试集上的判别正确率达到99.2%。该方法满足使用要求,可取代目视判别,提高了光伏用电致发光缺陷检测仪空间分辨率判定的准确性与重复性,并为其量化提出了新的解决思路。由于太阳电池片用光致发光缺陷检测仪与光伏用电致发光缺陷检测仪的成像方式类似,该方法可兼容太阳电池片光致发光检测仪的性能评估。     

重庆主城区城市空间结构演变与优化——基于公共服务功能组织视角

城市空间结构与城市公共服务功能组织密切相关。重庆主城区作为典型的"多中心、组团式"城市,在城市公共服务功能的就近组织、公共服务需求的均衡化方面具有先天的优势。本文梳理重庆主城区空间结构的演进历程以及与公共服务需求变化的互动关系,辨识随着城市功能由生产向消费转型,空间面临的结构问题及其内在动因,借鉴马斯洛理论,提出顺应当前及未来公共服务需求层次的分异,城市空间结构应从"多中心、组团式"进一步向"分层多中心、组团式"优化,引导形成相对集中、功能综合的基层"小、微中心"体系,以有序组织公共服务功能,最大限度地减少非必要交通出行,降低居民出行的时耗,提升城市效率,并借鉴恩格尔系数构建衡量城市效率的评价框架,为破解山地城市空间结构问题,推动城市空间转型提供新的思考视角。     

Comparing the expressiveness of downward fragments of the relation algebra with transitive closure on trees

Motivated by the continuing interest in the tree data model, we study the expressive power of downward navigational query languages on trees and chains. Basic navigational queries are built from the identity relation and edge relations using composition and union. We study the effects on relative expressiveness when we add transitive closure, projections, coprojections, intersection, and difference; this for Boolean queries and path queries on labeled and unlabeled structures. In all cases, we present the complete Hasse diagram. In particular, we establish, for each query language fragment that we study on trees, whether it is closed under difference and intersection.     

Relative vibration identification of cutter and workpiece based on improved bidimensional empirical mode decomposition

Frontiers of Mechanical Engineering - In the process of cutting, the relative vibration between the cutter and the workpiece has an important effect on the surface topography. In this study, the...     

Bio-economic modelling for marine spatial planning application in North Sea shrimp and flatfish fisheries

Marine activities have been increasingly competing for space and reducing areas for fishing. The use of spatially explicit tools can assist the decision making process on defining the optimal location of closures for fishing due to these emerging activities.This paper presents the Spatial Integrated bio-economic Model for FISHeries (SIMFISH). In this model fishers behaviour is simulated based on optimal effort allocation. The added value of this model compared to other existing spatial management tools lies in the presence of (i) short and long term fishers behaviour (ii) spatial explicit stock and fleet dynamics and (iii) relatively low data requirements.As an illustration, SIMFISH is applied in this paper to estimate the impact of area closures in the North Sea. Overall area closures have a negative impact on the profitability of the fleets. This would be worsened with higher fuel prices and decreased stock productivity.     

空间H形梁柱节点的节点域滞回性能试验研究

为研究空间效应对节点域滞回性能及稳定性的影响，设计了4个不同构造的空间H形梁柱节点试件，于柱端施加恒定轴向荷载，于柱弱轴平面梁端施加恒定反对称荷载，于柱强轴平面梁端施加反对称往复荷载。试验及分析结果表明：基于平面梁柱节点试验提出的考虑竖向连接板对提高节点域稳定性的推荐公式仍适用；柱弱轴平面不平衡弯矩通过竖向连接板及横向加劲肋传递至柱翼缘，当该荷载不致引起节点域周边构件过早屈服时，若传力路径连续，节点域不直接抵抗该荷载作用；在本试验的柱弱轴平面荷载应力水平下，构造设计合理的空间试件节点域的承载力、变形能力、稳定性、耗能能力均不低于相应的平面试件。     

The generic model query language GMQL – Conceptual specification,implementation, and runtime evaluation

The generic model query language GMQL is designed to query collections of conceptual models created in arbitrary graph-based modelling languages. Querying conceptual models means searching for particular model subgraphs that comply with a predefined pattern query. Such a query specifies the structural and semantic properties of the model fragment to be returned. In this paper, we derive requirements for a generic model query language from the literature and formally specify the language’s syntax and semantics. We conduct an analysis of GMQL׳s theoretical and practical runtime performance concluding that it returns query results within satisfactory time. Given its generic nature, GMQL contributes to a broad range of different model analysis scenarios ranging from business process compliance management to model translation and business process weakness detection. As GMQL returns results with acceptable runtime performance, it can be used to query large collections of hundreds or thousands of conceptual models containing not only process models, but also data models or organizational charts. In this paper, we furthermore evaluate GMQL against the backdrop of existing query approaches thereby carving out its advantages and limitations as well as pointing toward future research.     

空间经济学视角下城郊型开发区产城融合路径

首先从空间经济学视角分析了产城关系演变中的土地价值损失的形成及弥补过程,提出产城冲突下价值损失的构成、影响因素及扩大机制。随后,围绕价值损失的补偿方式指出了产城融合的三条路径,并对现实中各类路径的应用给出了宏观及微观解释——我国城镇化和工业化发展的阶段性变化、不同类型产业的产出效率及其就业人群需求差异是路径选择的决定性因素。最后,本文指出了进一步的研究方向,即通过合理的制度安排,减少产城融合过程中不同主体之间利益再分配所需的交易成本。     

Rapidly finding CAD features using database optimization

Automatic feature recognition aids downstream processes such as engineering analysis and manufacturing planning. Not all features can be defined in advance; a declarative approach allows engineers to specify new features without having to design algorithms to find them. Naive translation of declarations leads to executable algorithms with high time complexity. Database queries are also expressed declaratively; there is a large literature on optimizing query plans for efficient execution of database queries. Our earlier work investigated applying such technology to feature recognition, using a testbed interfacing a database system (SQLite) to a CAD modeler (CADfix). Feature declarations were translated into SQL queries which are then executed.The current paper extends this approach, using the PostgreSQL database, and provides several new insights: (i) query optimization works quite differently in these two databases, (ii) with care, an approach to query translation can be devised that works well for both databases, and (iii) when finding various simple common features, linear time performance can be achieved with respect to model size, with acceptable times for real industrial models. Further results also show how (i) lazy evaluation can be used to reduce the work performed by the CAD modeler, and (ii) estimating the time taken to compute various geometric operations can further improve the query plan. Experimental results are presented to validate our main conclusions.     

从空间管制角度谈对“多规合一”工作的思考

空间管制作为一种有效的空间资源配置和管理手段备受关注，也日益成为空间规划的重要内容和政府进行空间管理的重要抓手。要实现统一的空间管制，就必须进行“多规合一”。在“多规合一”的过程中，形成统一的控制线和空间管制分区，建立起“管制分区-责任主体-政策措施”三位一体的空间管制机制，并实现空间政策化，政策法制化。要实现管制空间与管制政策的协调，必须处理好技术理性与行政管理可操作性的关系，促使空间管制由技术性向政策性转型。完整的空间管制政策应包括三个部分，对管制分区的管理要求、实现管制目标的措施和空间开发权合理分配的保障机制。在明确分区管理控制性和约束性要求的同时，通过调节和补偿性政策措施，最终实现空间开发权的合理分配。