Triangulation Procedure Research Articles

Homeless Aging Veterans in Transition: A Life-Span Perspective

The need for counseling and career/educational services for homeless veterans has captured political and economic venues for more than 25 years. Veterans are three times more likely to become homeless than the general population if veterans live in poverty or are minority veterans. This mixed methods study emphasized a life-span perspective approach for exploring factors influencing normative aging and life-quality of 39 homeless veterans in Alabama and Florida. Seven descriptive quantitative and qualitative research questions framed the investigation. Study participants completed a quantitative survey reflecting their preferences and needs with a subset of the sample (N = 12) also participating in individual qualitative interview sessions. Thirty-two service providers and stakeholders completed quantitative surveys. Empirical and qualitative data with appropriate triangulation procedures provided interpretive information relative to a life-span development perspective. Study findings provide evidence of the need for future research efforts to address strategies that focus on the health and economic challenges of veterans before they are threatened with the possibility of homelessness. Implications of the study findings provide important information associated with the premise that human development occurs throughout life with specific characteristics influencing the individual's passage. Implications for aging/homelessness research are grounded in late-life transitioning and human development intervention considerations.

VEGETATION CHARACTERISTICS USING MULTI-RETURN TERRESTRIAL LASER SCANNER

Abstract. Distinguishing vegetation characteristics in a terrestrial laser scanner dataset is an interesting issue for environmental assessment. Methods for filtering vegetation points to distinguish them from ground class have been widely studied mostly on datasets derived from airborne laser scanner, less so for terrestrial laser scanners (TLS). Recent developments in terrestrial laser sensors – further ranges, faster acquisition and multiple return echoes for some models – has risen interest for surface modelling applications. The downside of TLS is that a typical dataset has a very dense cloud, with obvious side-effects on post-processing time. Here we use a scan from a sensor which provides evaluation of multiple target echoes providing with more than 70 million points on our study area. The area presents a complex set of features ranging from dense vegetation undergrowth to very steep and uneven terrain. The method consists on a first step which subsets the original points to define ground candidates by taking into account the ordinal return number and the amplitude. Next a custom progressive morphological filter (closing operation) is applied on ground candidate points using multidimensional (varying resolutions) grids and a structure element to determine cell values. Vegetation density mapping over the area is then estimated using a weighted ration of point counts in the tri-dimensional space over each cell. The overall result is a pipeline for processing TLS points clouds with minimal user interaction, producing a Digital Terrain Model (DTM), a Digital Surface Model (DSM) a vegetation density map and a derived canopy height model (CHM). Results on DTM show an accuracy (RMSE) of 0.307 m with a mean error of 0.0573 m compared to a control DTM extracted from Terrascan's progressive triangulation procedure. The derived CHM was tested over 30 tree heights resulting in 27 trees having an absolute error value below 0.2 m (three were just below 0.7 m).

A novel singular ES-FEM for crack growth simulation

A novel singular seven-node crack-tip triangular element with edge-based strain smoothing is formulated for modeling crack growth in solids. The present singular ES-FEM method uses a basic mesh of linear triangular elements and a special layer of seven-noded crack-tip elements connected to the crack-tip. The seven-noded crack-tip element has two additional nodes on each of the edges connected to the crack-tip, allowing efficient enrichment of the displacement field near the crack-tip without loss of partitions-of-unity property. The stiffness matrix of the discretized system is then obtained using the assumed displacement values (not the derivatives) over smoothing domains associated with the edges of elements. For crack propagation simulation, the Delaunay triangulation procedure associated with the Laplacian smoothing technique is used to automatically generate meshes. Several benchmark problems are used to show the accuracy and robustness of the proposed method.

Programmatic assessment and Kane’s validity perspective

Programmatic assessment is a notion that implies that the strength of the assessment process results from a careful combination of various assessment instruments. Accordingly, no single instrument is superior to another, but each has its own strengths, weaknesses and purpose in a programme. Yet, in terms of psychometric methods, a one-size-fits-all approach is often used. Kane's views on validity as represented by a series of arguments provide a useful framework from which to highlight the value of different widely used approaches to improve the quality and validity of assessment procedures. In this paper we discuss four inferences which form part of Kane's validity theory: from observations to scores; from scores to universe scores; from universe scores to target domain, and from target domain to construct. For each of these inferences, we provide examples and descriptions of approaches and arguments that may help to support the validity inference. As well as standard psychometric methods, a programme of assessment makes use of various other arguments, such as: item review and quality control, structuring and examiner training; probabilistic methods, saturation approaches and judgement processes, and epidemiological methods, collation, triangulation and member-checking procedures. In an assessment programme each of these can be used.

Spatial distribution of the absorption factor for an infinite cylindrical sample used with a two-dimensional area detector

Specialized software has been developed to calculate the absorption factor for the infinite-cylinder transmission Debye–Scherrer geometry (including inclined beams) to be used with two-dimensional area powder pattern registration. The diffracted beams are defined by the direction cosines in the laboratory Cartesian coordinate system. Modern two-dimensional area detectors have a large number of pixels, so an interpolation is made by the triangulation procedure to save computer time. The absorption correction is allowed for so that the intensity in each pixel is reduced on the same scale and the final diffraction-angle-dependent intensity,I(2θ), does not require any further absorption correction.

La planificación de la composición escrita por alumnado con discapacidad visual: un estudio de casos

The skill of writing constitutes a complex but essential learning process in school. This article describes a research project planned to discover the process through which visually impaired students approach writing and to identify their difficulties. The sample for the study was made up of six female and five male visually impaired students aged between 11.4 and 20.3 (average age 15.6). The research itself followed a qualitative focus and used the collective case study method. Data were collected in cognitive interviews through a questionnaire/guide offering students clues, in the form of questions, about the operations and processes inherent in planning. The questionnaire was designed and validated beforehand according to the experts� judgement and triangulation procedures. All the interviews were recorded and subsequently transcribed word for word. Research results were obtained via content analysis, by means of the appropriate categorisation system based on the theoretical model (Flower and Hayes 1981; Hayes 1996). The results revealed that in general students of this kind are familiar with the cognitive processes involved in planning written compositions, and they perform the operations planning entails when they face tasks requiring written expression in 77.9% of the cases. The recording of ideas and, to a lesser extent, the organization of ideas are the cognitive operations in which these individuals have the most trouble. The conclusions reveal that these students think about the objectives and ideas they want to write about in their text and also about the reader. No significant differences are found among students by age, sex or schooling level.

The great Martian catastrophe and how Kepler fixed it

For a few weeks every 32 years, both the Ptolemaic and Copernican predictions for the position of Mars are off by close to 5 degrees—a problem first noticed by Tycho Brahe.

Development of nurses’ abilities to reflect on how to create good caring relationships with patients in palliative care: an action research approach

Development of nurses' abilities to reflect on how to create good caring relationships with patients in palliative care: an action research approach In this paper we present an action research process aimed at enhancing nurses' abilities to reflect on how to create good caring relationships with patients in advanced home care. Another aim was to examine the usefulness of an emerging theory, derived from results from a previous study. The request for this project to take place came from an advanced home care unit which had received complaints concerning patients in the palliative phase. The action performed was clinical supervision, structured around abilities that nurses need in order to create good caring relationships. During the action research process 42 narratives were analysed by the participating group. Three different data collections were carried out and analysed with qualitative content analysis in a triangulation procedure. The emerging theory was found to be useful and was also refined. The nurses reported that they felt strengthened and had developed their ability to reflect over good caring relationships. Some changes to practice were carried out by the participating nurses. The result also indicates that action research can be helpful in examining the usefulness of an emerging theory.

Optimal Two-View Planar Scene Triangulation

We present a new algorithm for optimally computing from point correspondences over two images their 3-D positions using the knowledge that they are constrained to be on a planar surface. We consider two cases: the case in which the plane and camera parameters are known and the case in which they are not. In the former, we show how observed point correspondences are optimally corrected so that they are compatible with the homography between the two images. In the latter, we show how the homography is optimally estimated by iteratively using the triangulation procedure. Although the accuracy improvement over existing methods is very small, our algorithm has a theoretical merit of computing an exact maximum likelihood solution.

Point Selection for Triangular 2-D Mesh Design Using Adaptive Forward Tracking Algorithm

Two-dimensional mesh-based motion tracking preserves neighboring relations (through connectivity of the mesh) and also allows warping transformations between pairs of frames; thus, it effectively eliminates blocking artifacts that are common in motion compensation by block matching. However, available uniform 2-D mesh model enforces connec-tivity everywhere within a frame, which is clearly not suitable across occlusion boundaries. To overcome this limitation, BTBC (background to be covered) detection and MF (model failure) detection algorithms are being used. In this algorithm, connectivity of the mesh elements (patches) across covered and uncovered region boundaries are broken. This is achieved by allowing no node points within the background to be covered and refining the mesh structure within the model failure region at each frame. We modify the occlusion-adaptive, content-based mesh design and forward tracking algorithm used by Yucel Altunbasak for selection of points for triangular 2-D mesh design. Then, we propose a new triangulation procedure for mesh structure and also a new algorithm to justify connectivity of mesh structure after motion vector estimation of the mesh points. The modified content-based mesh is adaptive which eliminates the necessity of transmission of all node locations at each frame.

Lay and professional concepts of alcohol dependence in the process of recovery from addiction among treated and non-treated individuals in Poland: A qualitative study

The study identifies and categorizes concepts of addiction among treated and non-treated former alcohol dependents, and their function in the process of recovery from addiction within the post-communist treatment system dominated by the Minnesota model. This qualitative study is based on a media recruited sample of 29 former alcohol dependents (ICD-10) in Warsaw/Poland 2006/2007. They reported a recovery time of at least 2 years (Mrecovery = 11, SD = 9). In-depth interviews were analysed according to the Problem-Centred Interview method using Atlas.ti software. The applied triangulation procedures ensure reliability and validity of the data collected and the analysis of the narrative accounts. The results of the study show that professional concepts of addiction reconstructed on the basis of narratives from treated respondents resemble the disease model of addiction. A first category of lay concepts of self-changers adopt a medical–moral model of dependence including strong will as a key element of the successful recovery. A second category describes dependence as a symptom of maladaptive social functioning and recovery as a process of understanding one's role in society and fulfilling social expectations. While self-changers relied on one of these lay concepts, treated respondents were confronted with a conflict between lay and professional definition of dependence. It is argued that lack of recognition of lay concepts of addiction by treatment providers may weaken help-seeking and increase drop-out rates. The disease model implies the stability of the status of the alcoholic – which potentially weakens the individual's chance to reach the stage of stable recovery.

The need of collective expertise in noise control.

An effective and sustainable reduction of highly annoyed people caused by noise is only possible with further scientific endeavors in the area of methods development and research of noise effects. Soundscape suggests exploring noise in its complexity, its ambivalence, and its approach toward sound to consider the conditions and purposes of its production, perception, and evaluation, to understand evaluation of noise as a holistic approach. To bring soundscape into the area of community noise research means to focus on the meaning of sounds and its implicit assessments to contribute to the understanding that the evaluation through perceptual effects is a key issue. So‐called perception maps can provide meaningful information based on the local expertise. Local expertise in soundscape is a combination of meaningful knowledge about an area referring to the context of interactivity. The process of combining the data and analyzing them in a triangulation procedure will lead to the needed decisions. Within the ...

Experimental studies on impact damage location in composite aerospace structures using genetic algorithms and neural networks

Impact damage detection in composite structures has gained a considerable interest in many engineering areas. The capability to detect damage at the early stages reduces any risk of catastrophic failure. This paper compares two advanced signal processing methods for impact location in composite aircraft structures. The first method is based on a modified triangulation procedure and Genetic Algorithms whereas the second technique applies Artificial Neural Networks. A series of impacts is performed experimentally on a composite aircraft wing-box structure instrumented with low-profile, bonded piezoceramic sensors. The strain data are used for learning in the Neural Network approach. The triangulation procedure utilises the same data to establish impact velocities for various angles of strain wave propagation. The study demonstrates that both approaches are capable of good impact location estimates in this complex structure.

Challenges of Reliability and Validity in the Identification and Monitoring of Emerging Drug Trends

There is increasing pressure on drug monitoring systems to achieve earlier detection and greater precision in reporting of emerging drug use trends. Such systems typically operate in settings where government interest and the drug use trends themselves can be fluid. To achieve the goal of informing timely policy and practice responses in this environment, drug use monitoring systems must be flexible and responsive, as well as reliable and valid. This paper explores three interrelated areas relevant to trend monitoring that can benefit from a clearer focus in terms of increasing validity and reliability: the research paradigm to which systems adhere; the selection of sources or drug use indicators utilized by systems; and the process of analysis used by systems to ensure valid results. The reliability and validity of currently utilized drug use related indicators is discussed, with a focus on the validity of data sources as measures of emerging drug use trends. The relevance and utility of current descriptives such as “lagged” and “leading edge” indicators are assessed. Five dimensions, against which the validity of drug use indicators may be assessed in a trend-monitoring context are proposed as an alternative. Faced with a lack of clear conceptual frameworks underpinning and driving monitoring systems, it is argued that a pragmatic research paradigm can be adopted as a basis for guiding selection of indicators and helping to make explicit the concurrent or supplementary triangulation and analysis procedures on which valid results are necessarily founded. The current trend of using triangulation as the primary means of ensuring the validity of systems is critically reviewed and a challenge is issued to the field to make the analysis process more overt. No external funding was received for this article.

Retro-detective control structures for free-space optical communication links

A corner-cube-based retro-detection photocell is introduced. The structure consists of three independent and mutually perpendicular photodiodes (PDs), whose differential photocurrents can be used to probe the alignment state of incident beams. These differential photocurrents are used in an actively-controlled triangulation procedure to optimize the communication channel alignment in a free-space optical (FSO) system. The active downlink and passive uplink communication capabilities of this system are demonstrated.

Rapid estimation of ground-shaking maps for seismic emergency management in the Campania Region of southern Italy

Strong ground-shaking mapping soon after a moderate-to-large earthquake is crucial to recognize the areas that have suffered the largest damage and losses. These maps have a fundamental role for emergency services, loss estimation and planning of emergency actions by the Civil Protection Authorities. This is particularly important for areas with high seismic risk levels, such as the Campania-Lucania Region in southern Italy. Taking advantage of the Irpinia Seismic Network (ISNet), a recently installed dense and wide dynamic seismic network, we have developed a procedure for rapid estimation of ground-shaking maps after moderate-to-large earthquakes (GRSmap). This uses an optimal data gridding scheme designed to account for bi-dimensional features of strong ground-motion fields, such as directivity, radiation patterns and focal mechanisms, to which most damage can be correlated. The basis of the mapping technique is a triangulation procedure to locally correct predicted data at the triangle barycentres where their vertices correspond to seismic stations. The method has been tested off-line using a simulated M 6.6 earthquake located at the centre of ISNet and applied to data of the 23 November 1980 Irpina M 6.9 earthquake recorded by a sparse network. This has highlighted its ability to predict peak ground-motion parameters of large magnitude earthquakes with respect to the attenuation relationships.

Structural Transitions Of a Helicase-Partial Duplex DNA Complex during ATP Hydrolysis Cycle

Helicases are ATP-dependent enzymes that use the structural changes induced by ATP binding, hydrolysis and release to unwind double stranded nucleic acids. We have studied the structural transitions of partial duplex DNA bound E-coli Rep helicase monomer by in vitro single molecule Forster resonance energy transfer (FRET) methodology. Constrained triangulation procedures were applied globally on FRET measurements from eight Rep mutants, donor labeled at different residues, and three DNA substrates, acceptor labeled at different nucleotides on duplex, to study these conformational states. A total of 96 different measurements were performed and used in the triangulation analysis. Such over-sampling reduces the likelihood of a single site with unusual photophysical properties to negatively impact the results. Our results show that binding of ATPγS to Rep induces a large conformational change which is then reversed in two approximately equal steps during ATP dephosphorylation (ATP to ADP.Pi transition) and ADP release. We do not observe a significant conformational change upon phosphate release (ADP.Pi to ADP transition). The large conformational change upon ATPγS binding is consistent with the rotation of the Rep domains in a direction that brings them closer to the duplex. In addition, we show that Rep has a preference to bind to ssDNA/dsDNA junction compared to the other sites along the ssDNA. Finally, we show that Rep remains in the closed conformation during all ATP hydrolysis intermediates when bound to the vicinity of ssDNA/dsDNA junction. Our studies not only reveal the structural transitions of Rep helicase-partial duplex DNA complex during ATP hydrolysis cycle but also demonstrate the potential of triangulation analysis as a versatile single molecule technique for probing structural information in physiological conditions.

Triangulation and Dealing with The Realness of Qualitative Research

This paper provides a sociologists’ reflection of a sociologist on qualitative field research. Reflections will include some methodological and epistemological considerations that are connected with field work, while building the realness of the description and conclusions, i.e. constructing the quality of qualitative research. The intellectual process of doing research will be characterized by analysis of:
 
 description of investigated reality (tales of the field),
 analytical process,
 usage of commonsense research procedures (so called triangulation procedures), which are used in the field by the researcher and during analysis or writing a research report to adequately “re – present” researched reality.
 
 The three above mentioned stages of representation of reality are interwoven to create one complex intellectual process, which is called “field research”. The quality of qualitative research is the intellectual process where some procedures are used to create the accountability of research conclusions.

Implementing a Triangulation Protocol in Bereavement Research: A Methodological Discussion

Triangulation is a comparative strategy for examining data that strengthens qualitative and multi-method research. Despite the benefits of triangulation noted in the research methods literature, few concrete models for operationalization of protocols exist. Lack of documentation of explicit triangulation procedures is especially true in the area of bereavement research. This article describes how an interdisciplinary research team implemented a triangulation protocol in a study of the needs of bereaved parents. Triangulation enabled the integration of diverse data sources, methods, and disciplinary perspectives. These processes yielded a more meaningful typology of bereaved parents' needs than would have otherwise been possible. Extending the use of triangulation will enhance multi-faceted understandings of bereavement.

Algorithms for Multi-sensor and Multi-primitive Photogrammetric Triangulation

The steady evolution of mapping technology is leading to an increasing availability of multi-sensory geo-spatial datasets, such as data acquired by single-head frame cameras, multi-head frame cameras, line cameras, and light detection and ranging systems, at a reasonable cost. The complementary nature of the data collected by these systems makes their integration to obtain a complete description of the object space. However, such integration is only possible after accurate co-registration of the collected data to a common reference frame. The registration can be carried out reliably through a triangulation procedure which considers the characteristics of the involved data. This paper introduces algorithms for a multi-primitive and multi-sensory triangulation environment, which is geared towards taking advantage of the complementary characteristics of spatial data available from the above mentioned sensors. The triangulation procedure ensures the alignment of involved data to a common reference frame. The devised methodologies are tested and proven efficient through experiments using real multi-sensory data.