scholarly journals Application of Optimization Algorithms for Identification of Reference Points in a Monitoring Network

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1739
Author(s):  
Waldemar Odziemczyk
Keyword(s):  
Reference System ◽  
Monitoring Network ◽  
Reference Points ◽  
Stability Criteria ◽  
Common Reference ◽  
Points Of Interest ◽  
Geological Conditions ◽  
Spatial Size ◽  
Stable Points ◽  
Optimisation Algorithms

Geodetic measurements are commonly used in displacement analysis to determine the absolute values of displacements of points of interest. In order to properly determine the displacement values, it is necessary to correctly identify a subgroup of mutually stable points constituting a reference system. The complexity of this task depends on the spatial size of the network, the timespan of measurements and geological conditions affecting the type of changes in the location of points. As a consequence of the abovementioned factors, the task of stable identification in a longer timespan for a subgroup of points may produce equivocal results. In particular, it is likely that alternative subgroups of reference points meeting the mutual stability criteria will be selected, sometimes without common reference points. The proposed method of reference system identification utilises optimisation algorithms. Two such algorithms were tested, i.e., simulated annealing (SA) and Hooke-Jeeves (HJ) method. Two numerical examples were used to test the proposed method. Although in the first example both methods delivered a positive result, the second example showed the superiority of the SA method over the HJ. The proposed method can be considered a tool supporting the person analysing and making calculations in reaching the ultimate decision on reference points.

scholarly journals METHODOLOGY FOR ORIENTATION AND FUSION OF PHOTOGRAMMETRIC AND LIDARDATAS FOR MULTITEMPORAL STUDIES

2016 ◽  
Vol XLI-B7 ◽  
pp. 639-645
Author(s):  
C. Colomo-Jiménez ◽  
J. L. Pérez-García ◽  
T. Fernández-del Castillo ◽  
J. M. Gómez-López ◽  
A. T. Mozas-Calvache
Keyword(s):  
Reference System ◽  
Reference Model ◽  
Control Point ◽  
Lidar Data ◽  
Control Points ◽  
Maximum Information ◽  
Common Reference ◽  
Using Data ◽  
Stable Points ◽  
Proper Analysis

Nowadays, data fusion is one of the trends in geomatics sciences, due to the necessity of merging data from different kind of sensors and periods of time. Also, to extrract the maximum information from data and useful multitemporal analysis, an exact geoconnection of all datasets in a common and stable reference system is essential. The results of the application of a methodology for an integrated orientation into a common reference system using data obtained by LiDAR systems, digital and historical photogrammetric flights dataset, used for proper analysis in multitemporal studies, are presented in this paper. In order to analyse the results of the presented methodology, several photogrammetric datasets have been used. This data corresponds with digital and analogic data. The most current flight (2010) combines data obtained with digital photogrammetric camera and LiDAR sensor which will be used as reference model for all subsequent photogrammetry flights. The philosophy of the methodology consists of orientating all photogrammetric flights to the DEM obtained by LiDAR data. All the models obtained from every photogrammetric block are comparable in terms of the geometric resolution of each one. For that reason, altimetric stable points are extracted automatically from the LiDAR points cloud to use these points such as altimetric control point in the different flights that must be oriented. Using LiDAR control points, we demonstrate the improvement in the results between initial orientation and final results. Also it is possible to improve the planimetric correspondence between different photogrammetric blocks using only altimetric control points iteratively.

scholarly journals METHODOLOGY FOR ORIENTATION AND FUSION OF PHOTOGRAMMETRIC AND LIDARDATAS FOR MULTITEMPORAL STUDIES

2016 ◽  
Vol XLI-B7 ◽  
pp. 639-645
Author(s):  
C. Colomo-Jiménez ◽  
J. L. Pérez-García ◽  
T. Fernández-del Castillo ◽  
J. M. Gómez-López ◽  
A. T. Mozas-Calvache
Keyword(s):  
Reference System ◽  
Reference Model ◽  
Control Point ◽  
Lidar Data ◽  
Control Points ◽  
Maximum Information ◽  
Common Reference ◽  
Using Data ◽  
Stable Points ◽  
Proper Analysis

Nowadays, data fusion is one of the trends in geomatics sciences, due to the necessity of merging data from different kind of sensors and periods of time. Also, to extrract the maximum information from data and useful multitemporal analysis, an exact geoconnection of all datasets in a common and stable reference system is essential. The results of the application of a methodology for an integrated orientation into a common reference system using data obtained by LiDAR systems, digital and historical photogrammetric flights dataset, used for proper analysis in multitemporal studies, are presented in this paper. In order to analyse the results of the presented methodology, several photogrammetric datasets have been used. This data corresponds with digital and analogic data. The most current flight (2010) combines data obtained with digital photogrammetric camera and LiDAR sensor which will be used as reference model for all subsequent photogrammetry flights. The philosophy of the methodology consists of orientating all photogrammetric flights to the DEM obtained by LiDAR data. All the models obtained from every photogrammetric block are comparable in terms of the geometric resolution of each one. For that reason, altimetric stable points are extracted automatically from the LiDAR points cloud to use these points such as altimetric control point in the different flights that must be oriented. Using LiDAR control points, we demonstrate the improvement in the results between initial orientation and final results. Also it is possible to improve the planimetric correspondence between different photogrammetric blocks using only altimetric control points iteratively.

The Power of Metaphor in Bringing Clarity for Learners in Learner-Centered Design

2017 ◽  
pp. 274-290
Author(s):  
John Ewing ◽  
Doug Reid
Keyword(s):  
Learning Theory ◽  
Social Constructivism ◽  
Reference Points ◽  
Community Of Learners ◽  
Student Centered ◽  
Common Reference ◽  
Learner Centered ◽  
Knowledge Learning ◽  
Learner Centered Pedagogy

The study focuses on guiding students through an exploration of social constructivism model as it relates to the roles of instructor and learner. It explores the use of a metaphor, the dot, to demonstrate that metaphors can support deeper understanding of difficult concepts inherent in learner-centered and constructivist pedagogies. This research was conducted to ascertain whether metaphors provide common reference points for learners that can be used to build and test new assumptions of knowledge. Additionally, the study highlights challenges that learner-centered pedagogy face when identifying preconceived constructs and moving towards the adoption of new thoughts, perspectives, and reasoning. In theory, this study identified the continuing role that metaphors play in the learning theory and how the literature can be explored further. In practice, the study identified student-centered activities, which include the learner as a contributor to knowledge, learning in a community of learners, and empowering the learner to change.

scholarly journals The problem of credibility studies on deformations of engineering objects in the geologically unstable area of Szczecin

2018 ◽  
Vol 71 ◽  
pp. 00018
Author(s):  
Marek Zygmunt ◽  
Stefan Cacoń ◽  
Andrzej Piotrowski ◽  
Grzegorz Stępień
Keyword(s):  
Measurement System ◽  
Geological Structure ◽  
Reference Points ◽  
Test Method ◽  
Geological Conditions ◽  
Measurement Results ◽  
Basic Issue ◽  
Class 1 ◽  
Proper Diagnosis ◽  
Control And Measurement System

The location of reference points in deformation studies of engineering objects is often associated with low reliability of the obtained measurement results. This concerns the lack of proper diagnosis of the geological structure of the area. The reliability of deformation measurements is also low when we obtain data that only characterize the effects and not the cause-and-effects. The authors reviewed the influence of geological conditions on the formation of deformations of some engineering objects. The reference points were located in the immediate vicinity of the facilities, without taking into account the geological structure of the areas where the facilities were located. The proposed test method is based on a three-segment control and measurement system. An example of such considerations is the engineering facilities on the Grodzka and Ostrów Grabowski Island in the Szczecin area. The basic issue is to locate geologically stable areas in the vicinity of monitored engineering objects on the basis of geological substrate assessment and to analyse archival materials concerning periodical measurements of class 1 and 2 levelling lines in the Szczecin area. Reference points are located, which constitute the first segment of the control and measurement system. Subsequent segments of the system are organized with reference to the points of the first segment. This method provides reliable data on deformations of engineering objects.

scholarly journals An explicit solution for calculating optimum spawning stock size from Ricker’s stock recruitment model

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1623 ◽  
Author(s):  
Mark D. Scheuerell
Keyword(s):  
Explicit Solution ◽  
Model Fitting ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Stock Size ◽  
Points Of Interest ◽  
Spawning Stock ◽  
Stock Recruitment ◽  
Explicit Formulae ◽  
Recruitment Model

Stock-recruitment models have been used for decades in fisheries management as a means of formalizing the expected number of offspring that recruit to a fishery based on the number of parents. In particular, Ricker’s stock recruitment model is widely used due to its flexibility and ease with which the parameters can be estimated. After model fitting, the spawning stock size that produces the maximum sustainable yield (SMSY) to a fishery, and the harvest corresponding to it (UMSY), are two of the most common biological reference points of interest to fisheries managers. However, to date there has been no explicit solution for either reference point because of the transcendental nature of the equation needed to solve for them. Therefore, numerical or statistical approximations have been used for more than 30 years. Here I provide explicit formulae for calculating bothSMSYandUMSYin terms of the productivity and density-dependent parameters of Ricker’s model.

scholarly journals Reproductive hyperallometry and managing the world’s fisheries

2021 ◽  
Vol 118 (34) ◽  
pp. e2100695118
Author(s):  
Dustin J. Marshall ◽  
Michael Bode ◽  
Marc Mangel ◽  
Robert Arlinghaus ◽  
E. J. Dick
Keyword(s):  
Fisheries Management ◽  
Management Strategies ◽  
Reference Points ◽  
Target Level ◽  
Fish Stocks ◽  
Global Food Security ◽  
Common Reference ◽  
Future Assessment ◽  
Traditional Approaches ◽  
Global Food

Marine fisheries are an essential component of global food security, but many are close to their limits and some are overfished. The models that guide the management of these fisheries almost always assume reproduction is proportional to mass (isometry), when fecundity generally increases disproportionately to mass (hyperallometry). Judged against several management reference points, we show that assuming isometry overestimates the replenishment potential of exploited fish stocks by 22% (range: 2% to 78%) for 32 of the world’s largest fisheries, risking systematic overharvesting. We calculate that target catches based on assumptions of isometry are more than double those based on assumptions of hyperallometry for most species, such that common reference points are set twice as high as they should be to maintain the target level of replenishment. We also show that hyperallometric reproduction provides opportunities for increasing the efficacy of tools that are underused in standard fisheries management, such as protected areas or harvest slot limits. Adopting management strategies that conserve large, hyperfecund fish may, in some instances, result in higher yields relative to traditional approaches. We recommend that future assessment of reference points and quotas include reproductive hyperallometry unless there is clear evidence that it does not occur in that species.

Relationship between Coordinate Transformation Uncertainty and Arrangement of Common Reference Points in Large-Scale Metrology

2017 ◽  
Vol 870 ◽  
pp. 309-314
Author(s):  
Jia Rui Lin ◽  
Yu Ren ◽  
Yin Guo ◽  
Yong Jie Ren ◽  
Ling Hui Yang ◽  
...  
Keyword(s):  
Coordinate Transformation ◽  
Large Scale ◽  
Transformation Process ◽  
Reference Points ◽  
Estimation Model ◽  
Individual Measurement ◽  
Coordinate Measurement ◽  
Measurement Systems ◽  
Common Reference ◽  
The Relationship

Large-scale coordinate measurement frequently involves unifying coordinate frames of individual measurement systems by aligning two sets of common reference points, which is called coordinate transformation. During this transformation process, some uncertainty is introduced into the final measurement results from common points. This paper studies the relationship between this introduced uncertainty and common points in order to minimize it. First, an uncertainty estimation model of coordinate transformation is developed to quantify the introduced uncertainty. Then the relationship between the introduced uncertainty and the arrangement of the common points is simulationally and experimentally investigated and some feasible and efficient arrangements are proposed in view of minimizing it.

scholarly journals Use of Gravity Measurements in Defining and Realizing Reference Systems for Geodynamics

1980 ◽  
Vol 56 ◽  
pp. 217-223
Author(s):  
J. D. Boulanger ◽  
N. N. Pariisky ◽  
L. P. Pellinen
Keyword(s):  
Reference System ◽  
Reference Ellipsoid ◽  
Reference Points ◽  
Sufficient Information ◽  
Reference Systems ◽  
The Earth ◽  
Gravity Measurements ◽  
Terrestrial Reference System

AbstractSingle measurements of gravity cannot give sufficient information about the position of measuring points with respect to some terrestrial reference system. Only a set of gravimetric stations all over the Earth combined with a determination of their coordinates allows one to determine (from the solution of Molodensky’s problem) the heights of these stations with respect to a level ellipsoid with center at the geocenter. Given in addition their heights above some reference ellipsoid, whose position in the Earth’s body is fixed through a set of reference points on its surface, the position of the geocenter in the same reference system may be obtained.

scholarly journals Cartography For Cooperative Manoeuvres With Autonomous Land Vehicles

2010 ◽  
Vol 64 (1) ◽  
pp. 141-155 ◽  
Author(s):  
Javier Alonso ◽  
Vicente Milanés ◽  
Enrique Onieva ◽  
Joshué Pérez ◽  
Carlos González ◽  
...  
Keyword(s):  
Directed Graph ◽  
Relational Database ◽  
Autonomous Vehicles ◽  
Traffic Signals ◽  
Reference Points ◽  
Hierarchical Representation ◽  
Land Vehicles ◽  
Points Of Interest ◽  
Upper Level ◽  
New System

This article presents a cartographic system to facilitate cooperative manoeuvres among autonomous vehicles in a well-known environment. The main objective is to design an extended cartographic system to help in the navigation of autonomous vehicles. This system has to allow the vehicles not only to access the reference points needed for navigation, but also noticeable information such as the location and type of traffic signals, the proximity to a crossing, the streets en route, etc. To do this, a hierarchical representation of the information has been chosen, where the information has been stored in two levels. The lower level contains the archives with the Universal Traverse Mercator (UTM) coordinates of the points that define the reference segments to follow. The upper level contains a directed graph with the relational database in which streets, crossings, roundabouts and other points of interest are represented. Using this new system it is possible to know when the vehicle approaches a crossing, what other paths arrive at that crossing, and, should there be other vehicles circulating on those paths and arriving at the crossing, which one has the highest priority. The data obtained from the cartographic system is used by the autonomous vehicles for cooperative manoeuvres.

scholarly journals An improved multiple-frequency method for measuring in situ target strengths

2005 ◽  
Vol 62 (8) ◽  
pp. 1636-1646 ◽  
Author(s):  
Stéphane G. Conti ◽  
David A. Demer ◽  
Michael A. Soule ◽  
Jean H.E. Conti
Keyword(s):  
Reference System ◽  
Three Dimensional ◽  
Previous Method ◽  
Target Strength ◽  
System Transformation ◽  
Multiple Frequency ◽  
Frequency Method ◽  
Multiple Targets ◽  
Common Reference ◽  
The Individual

Abstract Refinements have been made to the multiple-frequency method for rejecting overlapping echoes when making target-strength measurements with split-beam echosounders described in Demer et al. (1999). The technique requires that echoes, simultaneously detected with two or more adjacent split-beam transducers of different frequencies, pass multiple-target rejection algorithms at each frequency, and characterize virtually identical three-dimensional target coordinates. To translate the coordinates into a common reference system for comparison, the previous method only considered relative transducer positions and assumed that the beam axes of the transducers were parallel. The method was improved by first, optimizing the accuracy and precision of the range and angular measurements of the individual frequency detections; and second, precisely determining acoustically the relative positions and angular orientations of the transducers, thus completely describing the reference-system transformation(s). Algorithms are presented for accurately and precisely estimating the transformation parameters, and efficiently rejecting multiple targets while retaining measurements of most single targets. These improvements are demonstrated through simulations, controlled test-tank experiments, and shipboard measurements using 38- and 120-kHz split-beam transducers. The results indicate that the improved multiple-frequency TS method can reject more than 97% of multiple targets, while allowing 99% of the resolvable single targets to be measured.

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