282 research outputs found
CHALLENGES IN FLYING QUADROTOR UNMANNED AERIAL VEHICLE FOR 3D INDOOR RECONSTRUCTION
Three-dimensional modelling plays a vital role in indoor 3D tracking, navigation, guidance and emergency evacuation. Reconstruction of indoor 3D models is still problematic, in part, because indoor spaces provide challenges less-documented than their outdoor counterparts. Challenges include obstacles curtailing image and point cloud capture, restricted accessibility and a wide array of indoor objects, each with unique semantics. Reconstruction of indoor environments can be achieved through a photogrammetric approach, e.g. by using image frames, aligned using recurring corresponding image points (CIP) to build coloured point clouds. Our experiments were conducted by flying a QUAV in three indoor environments and later reconstructing 3D models which were analysed under different conditions. Point clouds and meshes were created using Agisoft PhotoScan Professional. We concentrated on flight paths from two vantage points: 1) safety and security while flying indoors and 2) data collection needed for reconstruction of 3D models. We surmised that the main challenges in providing safe flight paths are related to the physical configuration of indoor environments, privacy issues, the presence of people and light conditions. We observed that the quality of recorded video used for 3D reconstruction has a high dependency on surface materials, wall textures and object types being reconstructed. Our results show that 3D indoor reconstruction predicated on video capture using a QUAV is indeed feasible, but close attention should be paid to flight paths and conditions ultimately influencing the quality of 3D models. Moreover, it should be decided in advance which objects need to be reconstructed, e.g. bare rooms or detailed furniture
RECONSTRUCTION OF ARCHITECTURAL HERITAGE WITH SYMMETRICAL COMPONENTS
Data capturing through either Lidar or photogrammetry, often results in incomplete and partial information related to a surface due to occlusion or inaccessibility of the clear object vision. In case of asymmetrical objects yet the reconstruction is unattainable by any means, meanwhile the approach for the development of the missing information could be done in cases of symmetrical objects. In this paper we have advised a semi-automatic approach for recreating missing or incomplete information from the partially captured data using space sub-division and 3D transformation. The study has been done on a 175 year-old building whose scanned information is available for only one side and captures a façade with four columns. The idea is to first extract the symmetrical parts through segmentation of different building parts. Then the columns with partial information have been oriented as per a reference plane based on the pose and centre computed from the horizontal parts. The instance is then used to fill in the lost information through duplication and transformation. This approach can be used to recreate structures with symmetrical elements, which are partially destroyed from withering, disaster, or any human intervention
Prognosis in patients with myocardial infarction with ST-elevation depending on the timing of interventional revascularization
Проверена е прогнозата (болничния и следболничния леталитет до края на 6-ия месец) при 300 болни (212 мъже и 88 жени) с първи миокарден инфаркт със ST- елевация (STEMI) на средна възраст 62.9 год. в зависимост от срока на извършената първична коронарна интервенция (PCI) след началото на симптомите. В зависимост от срока на извършената РСІ болните са разделени на 4 групи: до 3-ия, до 6-ия, до 12-ия и до 24-ия час след началото на инфаркта. Болничният леталитет за всички болни е 6.3%, a до края на 6-ия месец - 13.3%, еднакъв при І-ва и ІІ-ра група и достоверно по-малък, отколкото при ІІІ-та и ІV-та група, по-голям при жените, при болните над 65 г., с ФИ <35.0% и с тромботична оклузия на LM и LAD.The prognosis (in-hospital and post-hospitalization lethality by the end of the 6th moth) of 300 patients (212 men and 88 women) with a first myocardial infarction with ST-elevation (STEMI) at an average age of 62.9 years was studied depending on the timing of the conducted primary coronary intervention (PCI) after the onset of symptoms. Depending on the timing of the conducted PCI, the patients were divided into 4 groups: by the 3rd, 6th, 12th, and 24th hour after the onset of the infarction. The patients` in-hospital lethality was 6.3%, and that by the end of the 6th month - 13.3%. It was the same for groups I and II and significantly lower than in groups III and IV; higher in women, in patients over 65 years of age, with ejection fraction (EF) <35.0% and with thrombotic occlusion of LM and LAD
Distributed GIS for automated natural hazard zonation mapping internet-SMS warning towards sustainable society
Today, open systems are needed for real time analysis and warnings on geo-hazards and over time can be achieved using Open Source Geographical Information System (GIS)-based platform such as GeoNode which is being contributed to by developers around the world. To develop on an open source platform is a very vital component for better disaster information management as far as spatial data infrastructures are concerned and this would be extremely vital when huge databases are to be created and consulted regularly for city planning at different scales, particularly satellite images and maps of locations. There is a big need for spatially referenced data creation, analysis, and management. Some of the salient points that this research would be able to definitely contribute with GeoNode, being an open source platform, are facilitating the creation, sharing, and collaborative use of geospatial data. The objective is development of an automated natural hazard zonation system with Internet-short message service (SMS) warning utilizing geomatics for sustainable societies. A concept of developing an internet-resident geospatial geohazard warning system has been put forward in this research, which can communicate alerts via SMS. There has been a need to develop an automated integrated system to categorize hazard and issue warning that reaches users directly. At present, no web-enabled warning system exists which can disseminate warning after hazard evaluation at one go and in real time. The objective of this research work has been to formalize a notion of an integrated, independent, generalized, and automated geo-hazard warning system making use of geo-spatial data under popular usage platform. In this paper, a model of an automated geo-spatial hazard warning system has been elaborated. The functionality is to be modular in architecture having GIS-graphical user interface (GUI), input, understanding, rainfall prediction, expert, output, and warning modules. A simplified but working prototype of the system without the GIS-GUI module has been already tested, validated, and reported. Through this paper, a significantly enhanced system integrated with web-enabled-geospatial information has been proposed, and it can be concluded that an automated hazard warning system has been conceptualized and researched. However, now the scope is to develop it further
Chromatin: a tunable spring at work inside chromosomes
This paper focuses on mechanical aspects of chromatin biological functioning.
Within a basic geometric modeling of the chromatin assembly, we give for the
first time the complete set of elastic constants (twist and bend persistence
lengths, stretch modulus and twist-stretch coupling constant) of the so-called
30-nm chromatin fiber, in terms of DNA elastic properties and geometric
properties of the fiber assembly. The computation naturally embeds the fiber
within a current analytical model known as the ``extensible worm-like rope'',
allowing a straightforward prediction of the force-extension curves. We show
that these elastic constants are strongly sensitive to the linker length, up to
1 bp, or equivalently to its twist, and might locally reach very low values,
yielding a highly flexible and extensible domain in the fiber. In particular,
the twist-stretch coupling constant, reflecting the chirality of the chromatin
fiber, exhibits steep variations and sign changes when the linker length is
varied.
We argue that this tunable elasticity might be a key feature for chromatin
function, for instance in the initiation and regulation of transcription.Comment: 38 pages 15 figure
duality between bim and gis an example related to the medieval bridge azzone visconti
The paper presents the work carried out on the medieval bridge Azzone Visconti in Lecco, Italy. The project required the use of both BIM and GIS technologies to assess the loading capacity of the bridge. First, a detailed geometric survey was carried out with laser scanning and photogrammetric techniques. The aim was the generation of a BIM. Displacements were then measured via geometric levelling during loading tests carried out in different days. Such data were integrated and stored in the BIM. Finally, the simulation of traffic conditions was used to investigate the usability of the BIM for a geographic area around the bridge. Results highlighted that the BIM used in the first stage of the work had to be replaced with another integrated BIM-GIS solution more suitable for analysis based on geospatial data
AN ANALYSIS OF STUDENT SATISFACTION WITH THE ORGANIZATION OF HYBRID TEACHING IN THE DEPARTMENT OF HEALTH ECONOMICS
The PURPOSE of this research is for a survey to be conducted among the students of the Faculty of Public
Health “Prof. Tzekomir Vodenicharov, МD, DSc” at Medical University – Sofia to study whether they are
satisfied with how hybrid teaching has been organized in the Department of Health Economics. MATERIALS
AND METHODS: An anonymous questionnaire survey was conducted. Out of all students who were invited
to participate, 309 joined. The questionnaire was distributed through the Google Forms platform from June to
October 2022. Chi-Quadrant analysis was used in order to find relationships between categorical variables.
RESULTS: the result shows a statistically significant connection between the students who are studying
different specialties in the FPH and their satisfaction with the organization of the hybrid classes carried out by
the Department (p <0.001). From the participants’ responses, it is clear that the implementation of hybrid form
of teaching (in-person classes for practical training and online classes for theoretical study) carried out through
open educational resources and implementing innovative teaching methodology is preferred by the students.
CONCLUSION: The scientific evidence arising from our empirical research can aid in the development of
guidelines for practical improvement of the hybrid teaching organization in disciplines taught in the
Department. The conclusions drawn presuppose continuous research with proper methodologies applied
Global bundle adjustment with variable orientation point distance for precise mars express orbit reconstruction
The photogrammetric bundle adjustment of line scanner image data requires a precise description of the time-dependent image orientation. For this task exterior orientation parameters of discrete points are used to model position and viewing direction of a camera trajectory via polynomials. This paper investigates the influence of the distance between these orientation points on the quality of trajectory modeling. A new method adapts the distance along the trajectory to the available image information. Compared to a constant distance as used previously, a better reconstruction of the exterior orientation is possible, especially when image quality changes within a strip. In our research we use image strips of the High Resolution Stereo Camera (HRSC), taken to map the Martian surface. Several experiments on the global image data set have been carried out to investigate how the bundle adjustment improves the image orientation, if the new method is employed. For evaluation the forward intersection errors of 3D points derived from HRSC images, as well as their remaining height differences to the MOLA DTM are used. In 13.5 % (515 of 3,828) of the image strips, taken during this ongoing mission over the last 12 years, high frequency image distortions were found. Bundle adjustment with a constant orientation point distance was able to reconstruct the orbit in 239 (46.4 %) cases. A variable orientation point distance increased this number to 507 (98.6 %).German Federal Ministry for Economic Affairs and Energy (BMWi)German Aerospace Center (DLR)/50 QM 130
Mathematically provable correct implementation of integrated 2D and 3D representations
representation
Dendrimers in Nanoscale Confinement: The Interplay between Conformational Change and Nanopore Entrance
Hyperbranched dendrimers are nanocarriers for drugs, imaging agents, and catalysts. Their nanoscale confinement is of fundamental interest and occurs when dendrimers with bioactive payload block or pass biological nanochannels or when catalysts are entrapped in inorganic nanoporous support scaffolds. The molecular process of confinement and its effect on dendrimer conformations are, however, poorly understood. Here, we use single-molecule nanopore measurements and molecular dynamics simulations to establish an atomically detailed model of pore dendrimer interactions. We discover and explain that electrophoretic migration of polycationic PAMAM dendrimers into confined space is not dictated by the diameter of the branched molecules but by their size and generation-dependent compressibility. Differences in structural flexibility also rationalize the apparent anomaly that the experimental nanopore current read-out depends in nonlinear fashion on dendrimer size. Nanoscale confinement is inferred to reduce the protonation of the polycationic structures. Our model can likely be expanded to other dendrimers and be applied to improve the analysis of biophysical experiments, rationally design functional materials such as nanoporous filtration devices or nanoscale drug carriers that effectively pass biological pores
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