Terrestrial laser scanning for estimating urban tree volume and carbon content

The acquisition of single-tree-related information is an important task, especially in urban areas where there is an increasing interest in standing carbon stock. Therefore, an easy and robust method was developed to extract the volume, diameter at breast height (DBH) and height of single trees from point clouds of terrestrial laser scanning. For data acquisition, nine trees were scanned from several positions and the resulting high-resolution point clouds (20–60 million points) were analysed by an algorithm based on voxel structure. First, noise reduction was carried out, followed by filling of voxels inside the stem and branches through the intersection of four orthogonal viewing directions. After the elimination of erroneously generated fillings, volume was determined layer-wise for each cross section. For quality assessment, nine deciduous trees were selected, cut, weighed and analysed for wet specific gravity and carbon content in order to provide a control value. The estimated volumes agree with the control value within a range of –5.1% to +14.3%. This is also the case with DBH values; however, heights are systematically underestimated.     

Planar Segment Based Three‐dimensional Point Cloud Registration in Outdoor Environments

We present an odometry‐free three‐dimensional (3D) point cloud registration strategy for outdoor environments based on area attributed planar patches. The approach is split into three steps. The first step is to segment each point cloud into planar segments, utilizing a cached‐octree region growing algorithm, which does not require the 2.5D image‐like structure of organized point clouds. The second step is to calculate the area of each segment based on small local faces inspired by the idea of surface integrals. The third step is to find segment correspondences between overlapping point clouds using a search algorithm, and compute the transformation from determined correspondences. The transformation is searched globally so as to maximize a spherical correlation‐like metric by enumerating solutions derived from potential segment correspondences. The novelty of this step is that only the area and plane parameters of each segment are employed, and no prior pose estimation from other sensors is required. Four datasets have been used to evaluate the proposed approach, three of which are publicly available and one that stems from our custom‐built platform. Based on these datasets, the following evaluations have been done: segmentation speed benchmarking, segment area calculation accuracy and speed benchmarking, processing data acquired by scanners with different fields of view, comparison with the iterative closest point algorithm, robustness with respect to occlusions and partial observations, and registration accuracy compared to ground truth. Experimental results confirm that the approach offers an alternative to state‐of‐the‐art algorithms in plane‐rich environments.     

The emergence of distributed component platforms

Several vendors and consortia have independently developed standards that define the basic mechanics for building and interconnecting software components. Sun's JavaBeans has emerged as the leading rival to Microsoft's DCOM, supplanting the OpenDoc standard from the now defunct Component Integration Laboratories. Component software is moving from its original focus on desktop-bound compound documents to enterprise applications that include distributed server components. The backers of competing standards are racing to capture market leadership by delivering the tangible benefits of component standards via distributed component platforms-integrated development and runtime environments that isolate much of the conceptual and technical complexity involved in building component-based applications. With DCPs, businesses can assign their few highly skilled programmers to component construction and use less sophisticated developers to carry out the simpler assembly tasks. By making component standards available to the broadest possible spectrum of developers, DCPs essentially drive those standards to market. This article reviews the state of component software as embodied in DCPs. The two DCP market leaders are Microsoft's DCOM (or ActiveX/DCOM) and Sun's JavaBeans. However, Internet and OMG component standards are emerging that will likely impact both the content and status of these two DCPs. The article also discusses component frameworks, which extend DCPs to provide more complete application development solutions     

Objective and subjective assessments of socioeconomic status and their relationship to self-rated health in an ethnically diverse sample of pregnant women.

A new measure of subjective socioeconomic status (SES) was examined in relation to self-rated physical health in pregnant women. Except among African Americans, subjective SES was significantly related to education, household income, and occupation. Subjective SES was significantly related to self-rated health among all groups. In multiple regression analyses, subjective SES was a significant predictor of self-rated health after the effects of objective indicators were accounted for among White and Chinese American women; among African American women and Latinas, household income was the only significant predictor of self-rated health. After accounting for the effects of subjective SES on health, objective indicators made no additional contribution to explaining health among White and Chinese American women; household income continued to predict health after accounting for subjective SES among Latinas and African American women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultrasonic evaluation of geometrical and surface parameters of rough defects in solids

Ultrasonic measurements from rough cracks were carried out using both broad-band and narrow-band methods. An analysis is suggested to determine parameters of the crack quantitatively such as size, shape, rms surface roughness, and distribution function of the surface roughness. Ultrasonic measurements of the parameters compare very well with the actual parameters of the defect.     

A new method for the determination of direct insolation

A method of determining direct normal insolation by using two fixed pyranometers was developed and tested. Experimental data for two different configurations are presented. The results are such that the method presented could reasonably be substituted for the standard tracking pyrheliometer in situations in which the use of such a pyrheliometer is not practicable.     

Analysis of Distance Collaboration Modalities: Alternatives to Meeting Face-to-Face

Physical and temporal boundaries are rapidly diminishing in an age of swiftly advancing information communication technologies. Today’s technologically sophisticated business and organizational environments offer a number of distance collaboration modalities (DSMs) that can facilitate efficient and cost-effective meetings that have traditionally required face-to-face meeting venues. Selection of the DCMs that maximize meeting effectiveness is significantly challenging given the wide diversity of available options. Theory and empirical data can be useful as a guide in the selection of the most appropriate DCMs to maximize organizational productivity and success. This article reviews the literature on the behavioral and technical affordances and limitations of the various DCMs. It also provides a theoretical model based on media synchronicity theory to help guide selection of effective DCMs. This theoretical framework emphasizes the primacy of media alignment with core communication processes as well as social and interpersonal factors that influence meeting effectiveness.     

Liquid drop collisions on deformable media

The spatial and temporal distributions of the transient stresses generated in elastically deformable bodies with the elastic properties of zinc selenide, polymethylmethacrylate, and soda-lime glass have been evaluated for an idealized representation of a water drop impacting a plane surface. The development of regions of significant tensile stresses within the target material is clearly shown which can be related to fracture initiation in brittle materials. The analytical approach used has its inherent shortcomings which include the lack of obtaining the stresses at the surface in the vicinity of the Rayleigh wave front and the fact that it is only applicable to the earliest stages of the impact event before lateral outflow dominateS. However, the idealized model reasonably approximates the results from numerical analyses with regard to the water drop shape profile in the initial stage of the impact when the compressibility of the water in the drop is most significant. It does appear that the period of the collision covered by the analysis is where the damage within the material originates, whether due to the deformations within the impact zone or by the transient stress distribution established after the passage of the shear wave into the target material.