Positional Accuracy

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Verification of Dosimetric and Positional Accuracy of Dynamic Tumor Tracking  Intensity Modulated Radiation Therapy

Verification of Dosimetric and Positional Accuracy of Dynamic Tumor Tracking Intensity Modulated Radiation Therapy

Purpose: We performed both, dosimetric and positional accuracy verification of dynamic tumor tracking (DTT) intensity modulated radiation therapy (IMRT), with the Vero4DRT system using a moving phantom (QUASAR respiratory motion platform; QUASAR phantom) and system log files. Me- thods: The QUASAR phantom was placed on a treatment couch. Measure- ment of the point dose and dose distribution was performed for conventional IMRT, with the QUASAR phantom static and moving; for DTT IMRT, this was performed with the phantom moving for pyramid shaped, prostate, pa- ranasal sinus, and pancreas targets. The QUASAR phantom was driven by a sinusoidal signal in the superior-inferior direction. Furthermore, predicted positional errors induced by the Vero4DRT system and mechanical positional errors of the gimbal head, were calculated using the system log files. Results and Conclusion: For DTT IMRT, the dose at the evaluation point was within 3% compared with the verification plan, and the dose distribution in the passing rates of γ was 97.9%, with the criteria of 3% dose and 3 mm distance to agreement. The position error calculated from the log files was within 2 mm, suggesting the feasibility of employing DTT IMRT with high accuracy using the Vero4DRT system.

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The Land Based Positional Accuracy Of Gps And Gps Augmented By Gagan Over The Indian Geographical Region

The Land Based Positional Accuracy Of Gps And Gps Augmented By Gagan Over The Indian Geographical Region

ABSTRACT: The Global Positioning System, which was commonly known by the North American implementation called GPS; the GPS fails to provide an accurate Position, Navigation, and Time (PNT) signal over the Indian region. The positional accuracy of GPS is not up to the mark over the Indian region because the India is located near the equator. Moreover, the equatorial ionospheric grid point (IGP) of India differs from the ionospheric grid point of North America so in order to improve the positional accuracy of GPS over Indian region, the Indian Space Research Organization along with the Airport Authority of India has launched the space based augmentation satellite called GPS aided and Geo Augmented Navigation satellite (GAGAN) with PRN number 127 and 128. The GAGAN will make corrections in the ionospheric, ephemeris, and satellite clock errors in the navigation messages received from the GPS satellites; the certification of GAGAN is under progress. The objective of this research is to analyze the positional accuracy of GPS and GPS augmented by GAGAN over the Indian geographical region by using differential correction technique.

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Comparative Evaluation of Positional Accuracy of Implants with Two Different Splinting Materials using Two Different Elastomeric Impression Materials: An Invitro Study

Comparative Evaluation of Positional Accuracy of Implants with Two Different Splinting Materials using Two Different Elastomeric Impression Materials: An Invitro Study

This study was conducted to compare and evaluate the positional accuracy of implants with two different splinting materials using two different elastomeric impression materials. A reference model of the edentulous mandible with four implant replicas in the anterior region was fabricated in heat cure clear acrylic resin and was used as control group in this study (Control-Group R). The impression techniques were divided into two groups, pattern resin as splinting material using VPS and VPES as impression material and BisGMA as splinting material using VPS and VPES as impression material and grouped as Group I(A), II(A) and Group I(B), II(B) respectively. Five impressions of the reference models were made in each group with custom trays using VPS and VPES impression material. The impressions were poured using type IV dental stone and the retrieved master casts were grouped and evaluated for positional accuracy of inter implant relationship using a Coordinate measuring machine. Nine inter implant distances, three each in x, y and z axes and four implant angles in z axis were measured from the reference model and the master casts. The differences in the inter implant distances in x, y and z axes and the implant angular differences in the z-axis, in relation to the reference model were measured for all the casts. The results were tabulated and statistically analysed using one way ANOVA and Post-Hoc test.

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The effects of local street network characteristics on the positional accuracy of automated geocoding for geographic health studies

The effects of local street network characteristics on the positional accuracy of automated geocoding for geographic health studies

Finally, we computed tolerance regions for 95% of the bivariate distribution of positional errors. More specifi- cally, for each combination of rurality and orientation, we obtained 95% elliptical tolerance regions for an inner 95% of the distribution of positional errors. Both the normality-based region and the nonparametric region described previously were obtained. Results are dis- played in Figure 8. Normality-based tolerance regions for municipal addresses are seen to be smaller than those for rural addresses, but rurality appears to have almost no effect on the orientation of the region ’ s major axis, which is always aligned with street orientation apart from possibly a slight tilt. Nor does rurality appear to affect the ratio of the elliptical region ’ s major axis length to its minor axis length. For three of the four groups of addresses, the nonparametric region is slightly larger than its normality-based counterpart. The excep- tion is the group of municipal north-south addresses, for which the normality-based region appears to be dilated by the large concentration of extreme outliers in the upper left of the plot, which causes the sample

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Semi-dynamic geocentric datum for positional accuracy and reliability in Malaysia

Semi-dynamic geocentric datum for positional accuracy and reliability in Malaysia

In Malaysia, the Geocentric Datum of Malaysia 2000 (GDM2000) was developed by the Department of Survey and Mapping Malaysia (DSMM) to provide a global and homogeneous coordinate system across the country. The realization of the GDM2000 was based on the ITRF2000 at epoch 1 st January 2000 (DSMM, 2009). Since Malaysia has experienced land deformation due to plate tectonic motion and a series of earthquakes, thus, there are a number of questions raised: (1) is the current GDM2000 sufficiently reliable to be utilised for present positioning practice when associated with inexorable motion due to tectonic plates and earthquakes? (2) how does the GDM2000 account for heterogeneous land deformations in terms of spatio-temporal? and (3) how to obtain accurate coordinates as function of time? Therefore, there is a need for a comprehensive strategy to enhance and maintain high geospatial accuracy of the geocentric datum in terms of consistency to the ITRF and reliability of the positioning results with respect to time.

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Quality Assessment of the Canadian OpenStreetMap Road Networks

Quality Assessment of the Canadian OpenStreetMap Road Networks

This study evaluated the extrinsic quality of the Canadian OSM street networks in terms of completeness, positional accuracy, attribute accuracy and semantic accuracy. The overall OSM quality in Canada is comparable with DMTI, although spatial heterogeneity is a common theme across all quality measures. Urban areas received more contributions than rural areas, and footways were favored over motorways by contributors in general. The extrinsic quality results were then analyzed with intrinsic quality indicators to explore the possibility of using trust as proxies for OSM quality assessment at a small scale, but failed to identify any statistically significant relationships between tested variables. As an exception, GeoBase-sourced road segments have lightly and commonly improved quality. For future work, other features, such as buildings and points of interest, can be evaluated. Measures such as temporal quality and logical consistency can be examined in addition. Lastly, non-linear models can be tested in non-spatial and spatial analyses.

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Eelgrass Distribution in the Great Bay Estuary and Piscataqua River for 2017

Eelgrass Distribution in the Great Bay Estuary and Piscataqua River for 2017

If we do not meet the positional accuracy requirements, then we are prepared to follow a traditional workflow of running the aerotriangulation (AT) process. Typically, the aerotriangulation (also called bridging) process is used to densify the ground control network and the AGPS, and to extend the limited control into every frame of photography. The process involves measuring points on each stereo model, tying the stereo models into strips, and then tying the strips into a block. The block is then transformed to fit the existing scaled ground control. A sophisticated least squares algorithm is then used to adjust all of the measurement values simultaneously to achieve a best fit solution.

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Validating the map of current semi-natural ecosystem types in Germany and their upscaling using the Kellerwald-Edersee National Park as an example

Validating the map of current semi-natural ecosystem types in Germany and their upscaling using the Kellerwald-Edersee National Park as an example

The estimation of the absolute positional accuracy of the cEsT surface geometries, i.e., their proximity to the true position value, was made by comparison with data of known positional accuracy. The Digital Basic Landscape Model (Basic DLM) of the Official Topographic Carto- graphic Information System Hessen (ATKIS Hessen) with a geometric accuracy of ± 3 m [7] was used as the reference data set. All deciduous, mixed and coniferous forests of the ATKIS-DLM were combined into a land use class “forest” and spatially overlaid with the land objects of the cEsT (forest and forest ecosystem types). Between 400 apparently identical entities in total, the distances between the respective representatives were measured Table 1 Quality characteristics (according to DIN EN ISO 19113, [4]) and methods used

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Image Integration and On-Screen Digitizing Method of Geographic Information System Update and Maintenance Applied to the Hofmann Forest

Image Integration and On-Screen Digitizing Method of Geographic Information System Update and Maintenance Applied to the Hofmann Forest

Differentially corrected GPS data will have almost no bias and very low noise (Lange 1997). Bias is a constant error that affects accuracy with respect to truth. Noise is random, often quicker, fluctuation in GPS positions that may prevent high repeatability. GPS control points can be used to register manually digitized data layers, resulting in a spatial database with higher overall positional accuracy. GPS control points can be used to rectify aerial photographs and satellite images as well. When a sufficient number of equally distributed GPS points is collected for an area of interest, those points can be tied to features recognizable on associated imagery. The imagery can be shifted and reshaped to more closely match the more accurate, precise GPS point locations.

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Comparison of Different Methods to Rectify IKONOS Imagery without Use of Sensor Viewing Geometry.

Comparison of Different Methods to Rectify IKONOS Imagery without Use of Sensor Viewing Geometry.

Abstract: Satellite images can be rectified and adapted to map representation also without information about viewing geometry of the sensor. Polynomial Functions (PFs) or Rational Polynomial Functions (RPFs) can be applied for this purpose, both requiring Ground Control Points (GCPs), of which the positions in the image as well as in the real world must be known. Typically for PFs only planimetric (X, Y) positions of GCPs are used while for RPFs 3D coordinates (X, Y, Z) of them as well as a DEM (Digital Elevation Model) of the entire scene are required. Check Points (CPs) with the same characteristics of GCPs (but not coincident with them) are used to better verify the accuracy of the product. Not only topographic survey, but also maps or ortho-photos with adequate resolution supply the coordinates of GCPs as well as CPs. This paper is aimed to compare methods to rectify IKONOS images based on PFs or RPFs applications, considering the positional accuracy of the results as index for performance evaluation. Tests were executed on IKONOS panchromatic image of an area of the Cilento and Vallo di Diano National Park, in Campania Region (Italy): ortho-photos (scale 1:10,000) were used for GCPs and CPs planimetric position in the real world while for RPFs applications also DEM (cell size 20 m) was considered as source of 3D information. To compare the selected methods, differences (residuals) between the X, Y coordinates of GCPs (but also of the CPs) on the ortho-photos and corresponding values in the rectified image were calculated and evaluated. The positional accuracy of the resulting products in relation to the method as well as to the number of GCPs was analyzed; also the implications of the calculation of Rational Polynomial Coefficients (RPCs) in alternative to the use of the values supplied for them by the image provider were investigated.

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Regulative feedback in pattern formation: towards a general relativistic theory of positional information

Regulative feedback in pattern formation: towards a general relativistic theory of positional information

Fig. 2. Examples of regulatory feedback involved in positional specification by morphogen gradients. (A) The gap gene system of Drosophila melanogaster. Maternal morphogen gradients (such as Bcd) bias target nuclei towards the expression of specific gap genes according to their position along the anteroposterior (AP) axis of the embryo. The positions of the central and posterior domains of Krüppel (Kr), knirps (kni), giant (gt) and hunchback (hb) are shown diagrammatically, indicating the two pairs of staggered, mutually complementary domains along the AP axis (anterior, left). Cross- repressive feedback between complementary gap genes stabilises and sharpens these patterns (thick T-bars). A second layer of cross- repression with posterior dominance (thin T-bars) leads to anterior shifts in expression domain boundaries (indicated by coloured arrows). (B) Feedback between signalling ligands (morphogens) and their receptors or downstream pathways in the Drosophila wing disc. (Left) Hedgehog (Hh) signalling upregulates Patched (Ptc) receptor expression, which inhibits Hh movement by sequestering it extracellularly. (Centre) Wingless (Wg) signalling downregulates expression of its receptor Frizzled2 (Fz2) close to the Wg source. High levels of Fz2 away from the source stabilise the Wg protein. (Right) Decapentaplegic (Dpp) signalling downregulates expression of its receptor Thickveins (Tkv) close to its source. Tkv in turn sensitises cells away from the source to low levels of Dpp signalling. (C) Sonic Hedgehog (Shh) in the vertebrate neural tube (NT) is regulated by multiple levels of feedback. Shh (blue circles) up-regulates expression of its receptor Ptc1 (red), which inhibits signalling by repressing the co-receptor Smoothened (Smo, orange circles). This desensitises cells in the region of the gradient where ligand is limiting (in the dorsal NT, right) and alters the shape of the gradient (indicated by different blue shading). Yellow stars indicate signalling events. Brief Shh signalling activity induces expression of the target gene Olig2 (white). Maintained levels of Shh induce Nkx2.2 (blue), which in turn represses Olig2 (T-bar). Red indicates dorsal (Class I) Shh target genes, such as Irx3 and Pax6. (D) Dorsoventral patterning in the Drosophila embryo. Dpp/Scw heterodimers diffuse dorsally in a complex with Twisted Gastrulation (Tsg) and Short Gastrulation (Sog). They are captured and enriched at the dorsal midline by a surface bound ligand binding protein (SBP), whose expression is upregulated by Dpp signalling. This leads to the sharpening and narrowing of the dorsal stripe of Dpp activity (measured as the concentration of

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Transitional probabilities count more than frequency, but might not be used for memorization

Transitional probabilities count more than frequency, but might not be used for memorization

Further, in actual learning situations, positional edge information might not only be provided directly by prosodic boundary cues, but also indirectly, via posi- tional phonotactics. Previous research has shown that adults and infants can learn which phonemes are allowed at the edges of words (e.g., Chambers, Onishi, & Fisher, 2003; Onishi, Chambers, & Fisher, 2002) or utterances (Sohail & Johnson, 2016), and such phonotactic learn- ing is more flexible at word-edges than at other positions within words (Endress & Mehler, 2010). Monaghan and Christiansen (2010) proposed a computational model, where learners keep a list of diphone pairs at utterance boundaries. This list is constructed from those words that are known to the learner at a given stage, and is used to guide segmentation. Using this simple ap- proach, Monaghan and Christiansen (2010) found excel- lent segmentation performance that, to our knowledge, compares favorably with all other segmentation mecha- nisms that have been proposed so far, and, importantly, is based on information at edges of words.

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Positional Preferences: Efficiency and Distortions under Welfarist  and Paternalistic Governments

Positional Preferences: Efficiency and Distortions under Welfarist and Paternalistic Governments

Abstract. This paper analyzes the distortionary effects of positional preferences when labor supply is exogenous under both a welfarist and a paternalistic govern- ment. Extending the prior literature, reference levels may be partially exogenous to the government (e.g., determined by consumption choices in a foreign country), and individuals may be positional with respect to wealth in addition to consump- tion. Neither consumption- nor consumption-cum-wealth positionality needs to cause inter-temporal distortions under either welfare criterion. We derive necessary and sufficient conditions for non-distortion of positional preferences. If those condi- tions are not satisfied, the same reference levels of consumption and wealth can give rise to under-saving or to over-saving – depending on the extend to which the ref- erence levels are exogenous to the government. Moreover, we provide conditions for which positional preferences for wealth and consumption imply over-consumption with respect to the welfarist criterion but, at the same time, over-saving with re- spect to the paternalistic criterion.

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Intra-Positional and Inter-Positional Differences in Somatotype Components and Proportions of Particular Somatotype Categories in Youth Volleyball Players

Intra-Positional and Inter-Positional Differences in Somatotype Components and Proportions of Particular Somatotype Categories in Youth Volleyball Players

It is therefore surprising that in already relatively rare studies on young female volleyball players (1,18-21) inter-positional differences in somatotype have not been investigated. Studies in which those differences were analysed on a sample of senior female volleyball players are rare (17,22,23). In our previous study (12) two young national team members who play at libero and middle blocker position were selected from the overall sample. Obvious differences in their somatotypes, despite the same performance level, indirectly pointed to the necessity of further analysis of somatotype components according to positions. It was emphasized in the same study that the calculation of mean values of the somatotype components without individual classification of players into somatotype categories does not allow insight into the somatotype specificities of individual players.

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Positional Information Storage in Sequence Patterns

Positional Information Storage in Sequence Patterns

We build a model of storage of well-defined positional information in probabilistic sequence patterns. Once a pattern is defined, it is possible to judge the effect of any mutation in it. We show that the frequency of beneficial mutations can be high in general and the same mutation can be either advantageous or deleterious depending on the pattern’s context. The model allows to treat positional information as a physical quantity, formulate its conservation law and to model its continuous evolution in a whole genome, with meaningful applications of basic physical principles such as optimal effi- ciency and channel capacity. A plausible example of optimal solution analytically describes phase transitions-like beha- vior. The model shows that, in principle, it is possible to store error-free information on sequences with arbitrary low conservation. The described theoretical framework allows one to approach from novel general perspectives such long-standing paradoxes as excessive junk DNA in large genomes or the corresponding G- and C-values paradoxes. We also expect it to have an effect on a number of fundamental concepts in population genetics including the neutral theory, cost-of-selection dilemma, error catastrophe and others.

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Product Proliferation and Pricing in a Market with Positional Effects

Product Proliferation and Pricing in a Market with Positional Effects

Relative consumption and positional effects have been more widely studied in other areas of economics. The public finance literature has given some attention to relative consumption and positional effects, and in particular in their implications for taxation and public goods provision (e.g., Boskin and Sheshinski, 1978, Ljungqvist and Uhlig 2000, and Wendner and Goulder 2008). In the most recent contribution to this literature, Hopkins and Kornienko (2009) formulate a model in which consumers derive utility from a consumption good and from status (obtained based on relative consumption of a positional good). In their framework, prices are exogenous and there is a single variant of each good; consumer choice corresponds to the allocation of income to units of the each good. They focus on how changes in the distribution of income affect consumer utility, and how the government can affect welfare through taxation. Positional considerations also have implications for macroeconomics (e.g., Abel 1990 and Dupor and Liu 2003). Much of the literature emphasizes the effects of positional concerns on consumption and draws some broader conclusions (e.g., Clark and Oswald 1998, and Alpizar, Carlsson and Johansson-Stenman 2005). Somewhat unique from these research agendas is the contribution of Moldovanu, Sela, and Shi (2007) who show that positional preferences can also be used by a firm (or a society) for the design of performance-based award levels to better incentivize workers (or citizens).

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Positional Non-Cooperative Equilibrium

Positional Non-Cooperative Equilibrium

Let us assume for simplicity that π = π is equal for all players. The game in absolute consumption has only one Nash equilib- rium in pure strategies which is ( 1 , 0 ) . Let us further assume that both players assign a low positionality index to the posi- tional good at stake; if this is the case, we should expect small differences in their status functions, since the positional com- petition tends to a competition for public goods. Therefore let us set π = 0. Thus the matrix of the associated game results:

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μ3 Acetato μ2 acetato (di­methyl­form­amide)­penta­kis­(μ N,2 dioxido­benzene 1 carboximidato)penta­kis­(1 methyl 1H imidazole)­penta­manganese(III)manganese(II)–di­ethyl ether–di­methyl­formamide–methanol–water (1/1/1/1/0 49)

μ3 Acetato μ2 acetato (di­methyl­form­amide)­penta­kis­(μ N,2 dioxido­benzene 1 carboximidato)penta­kis­(1 methyl 1H imidazole)­penta­manganese(III)manganese(II)–di­ethyl ether–di­methyl­formamide–methanol–water (1/1/1/1/0 49)

metallacrown, OAc is acetate, shi 3 is salicylhydroximate, Me—Im is 1-methylimidazole, DMF is N,N-dimethyl- formamide, and MeOH is methanol), is comprised of five Mn III ions in the metallacrown ring and an Mn II ion which is encapsulated in the central cavity. Four of the ring Mn III ions are six-coordinate with distorted octahedral geometries. Two of these Mn III ions have a planar configuration, while the other two Mn III have absolute stereoconfiguration. The fifth Mn III is five-coordinated with distorted square-pyramidal geometry. Four of the ring Mn III ions each bind one 1- methylimidazole, while the final ring Mn III ion binds a DMF solvent molecule in an axial position and located in a trans position is either a Me—Im or a DMF molecule. The occupancy ratio of Me—Im to DMF is 0.62 (2) to 0.38 (2). The central Mn II is seven-coordinate with a geometry best described as distorted face-capped trigonal–prismatic. DMF, diethyl ether, MeOH, and water molecules are located in the interstitial voids between the metallacrown molecules. The methanol molecule is positionally disordered [0.51 (1): 0.49 (1)] and associated with a partially occupied water molecule [0.49 (1)]. This disorder is also associated with the positional disorder of the diethyl ether molecule [0.51 (1):0.49 (1)].

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Approaches for Improved Positional Proteomics

Approaches for Improved Positional Proteomics

Another attempt to simultaneously validating the results of positional proteomics is to use iTRAQ to modify the peptide N-termini and this workflow was tested for its application to identify protease substrates. In this study, both control and protease treated sample were labeled by different tags, allowing direct comparison of protein N-termini with neo-N-termini. In addition, samples were analyzed in duplicate by labeling with two tags (e.g. tag 116 and tag 117), aiming for quick validation of peptides by internal replicates. Compared with dimethylation or acetylation modification, the dramatic advantage of using iTRAQ as labeling reagent is that up to 4 or 8 samples can be compared simultaneously with sensitivity improvement, which makes it an attractive approach for the establishment of proteolytic signatures in vivo. This work was presented in chapter 4.

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Preference Intensity in Positional Voting

Preference Intensity in Positional Voting

Notice that we cannot directly apply group size effects in the same way as in the literature on Cournot games(Selten [8], Huck et al. [9]), where, as the numbers of firm increases, the underlying equilibrium structure moves in the direction of increasing competition (and increasing instability of collusive behavior). In the context of positional voting, the (anti)coordination structure we identify in Appendix A in the case of 2 players, basically carries through for larger group sizes, with the basic difference that coordination is made more difficult as it involves a larger number of players.

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