Iskanje po repozitoriju

A+ | A- | | SLO | ENG

Povzetek: Standard applicators for cervical cancer Brachytherapy (BT) do not always achieve acceptable balance between target volume and normal tissue irradiation. We aimed to develop an innovative method of Targetvolume Density Mapping (TDM) for modelling of novel applicator prototypes with optimal coverage characteristics. Patients and methods. Development of Contour-Analysis Tool 2 (CAT-2) software for TDM generation was the core priority of our task group. Main requests regarding software functionalities were formulated and guided the coding process. Software validation and accuracy check was performed using phantom objects. Concepts and terms for standardized workflow of TDM post-processing and applicator development were introduced. Results. CAT-2 enables applicator-based co-registration of Digital Imaging and Communications in Medicine (DICOM) structures from a sample of cases, generating a TDM with pooled contours in applicator-eye-view. Each TDM voxel is assigned a value, corresponding to the number of target contours encompassing that voxel. Values are converted to grey levels and transformed to DICOM image, which is transported to the treatment planning system. Iso-density contours (IDC) are generated as lines, connecting voxels with same grey levels. Residual Volume at Risk (RVR) is created for each IDC as potential volume that could contain organs at risk. Finally, standard and prototype applicators are applied on the TDM and virtual dose planning is performed. Dose volume histogram (DVH) parameters are recorded for individual IDC and RVR delineations and characteristic curves generated. Optimal applicator configuration is determined in an iterative manner based on comparison of characteristic curves, virtual implant complexities and isodose distributions. Conclusions. Using the TDM approach, virtual applicator prototypes capable of conformal coverage of any target volume, can be modelled. Further systematic assessment, including studies on clinical feasibility, safety and effectiveness are needed before routine use of novel prototypes can be considered.
Ključne besede: cervical cancer, brachytherapy, applicators, virtual modelling
Objavljeno v DiRROS: 09.05.2024; Ogledov: 390; Prenosov: 169
Celotno besedilo (671,88 KB)

Povzetek: Currently, the standard method of programming industrial robots is to perform it manually, which is cumbersome and time-consuming. Thus, it can be a burden for the flexibility of inspection systems when a new component with a different design needs to be inspected. Therefore, developing a way to automate the task of generating a robotic trajectory offers a substantial improvement in the field of automated manufacturing and quality inspection. This paper proposes and evaluates a methodology for automatizing the process of scanning a 3D surface for the purpose of quality inspection using only visual feedback. The paper is divided into three sub-tasks in the same general setting: (1) autonomously finding the optimal distance of the camera on the robot’s end-effector from the surface, (2) autonomously generating a trajectory to scan an unknown surface, and (3) autonomous localization and scan of a surface with a known shape, but with an unknown position. The novelty of this work lies in the application that only uses visual feedback, through the image focus measure, for determination and optimization of the motion. This reduces the complexity and the cost of such a setup. The methods developed have been tested in simulation and in real-world experiments and it was possible to obtain a precision in the optimal pose of the robot under 1 mm in translational, and 0.1° in angular directions. It took less than 50 iterations to generate a trajectory for scanning an unknown free-form surface. Finally, with less than 30 iterations during the experiments it was possible to localize the position of the surface. Overall, the results of the proposed methodologies show that they can bring substantial improvement to the task of automatic motion generation for visual quality inspection.
Ključne besede: robot learning, eobotic quality inspection, visual quality inspection
Objavljeno v DiRROS: 09.05.2024; Ogledov: 451; Prenosov: 579
Celotno besedilo (3,00 MB)
Gradivo ima več datotek! Več...

Povzetek: Predicting global change mitigations based on environmental variables, like temperature and water availability, although yielding insightful hypothesis still lacks the integration of environmental responses. Physiological limits should be assessed to obtain a complete representation of a species’ fundamental niche. Detailed ecophysiological studies on the response of trees along the latitudinal gradient are rare. They could shed light on the behaviour under different light intensities and other studied traits. The forests of the Dinaric Mountains and the Carpathians represent the largest contiguous forest complexes in south-eastern Europe. In uneven-aged Carpathian (8 plots) and Dinaric Mountain (11 plots) forests, net assimilation (Amax) and maximum quantum yield (Φ) were measured for beech and fir in three predefined light intensity categories according to the indirect site factor (ISF%) obtained by the analysis of hemispherical photographs in managed and old growth forests, all located above 800 m a.s.l. The measurements were carried out under fixed environmental conditions in each light category per plot for three consecutive years. Data from the last 50-year average period from the CRU TS 4.01 dataset were used for the comparison between Amax, Φ, and climate. The highest Φ for beech were observed in the central part of the Dinaric Mountains and in the south westernmost and northwesternmost part of the Carpathians for both beech and fir, while they were highest for fir in the Dinaric Mountains in the northwesternmost part of the study area. The Φ-value of beech decreased in both complexes with increasing mean annual temperature and was highest in the open landscape. For fir in the Carpathians, Φ decreased with increasing mean annual temperature, while in the Dinaric Mountains it increased with higher temperature and showed a more scattered response compared to the Carpathians. Short-term ecophysiological responses of beech and fir were consistent to long-term radial growth observations observed on same locations. The results may provide a basis and an indication of the future response of two tree species in their biogeographical range to climate change in terms of competitiveness, existence and consequently forest management decisions.
Ključne besede: silver fir, beech, light response, Carpathian Mountains, Dinaric Mountains, temperature, precipitation
Objavljeno v DiRROS: 08.05.2024; Ogledov: 419; Prenosov: 528
Celotno besedilo (1,56 MB)
Gradivo ima več datotek! Več...

Povzetek: Župnija Zgonik je najjužnejši izrastek goriške nadškofije v širšem kraškem zaledju tržaškega mesta. Prispevek obravnava demografske značilnosti starostnikov te župnije v dolgem 19. stoletju na osnovi treh statusov animarum. Delež starejših se je gibal okoli desetih odstotkov celotne populacije in je le polagoma naraščal, pretežno zaradi naraščanja števila starostnikov v šestdesetih letih starosti. Daleč največ starostnikov je umiralo »zaradi starosti«, pri čemer se je delež tega vzroka smrti na začetku 20. stoletja celo zopet povečal.
Objavljeno v DiRROS: 07.05.2024; Ogledov: 316; Prenosov: 166
Celotno besedilo (664,72 KB)
Gradivo ima več datotek! Več...

Povzetek: We present a procedure which enables the computation and the description of structures of isotropy subgroups of the group of complex orthogonal matrices with respect to the action of $^\ast$congruence on Hermitian matrices. A key ingredient in our proof is an algorithm giving solutions of a certain rectangular block (complex-alternating) upper triangular Toeplitz matrix equation.
Ključne besede: isotropy groups, matrix equations, complex orthogonal matrices, Hermitian matrices, Toeplitz matrices
Objavljeno v DiRROS: 06.05.2024; Ogledov: 488; Prenosov: 297
Celotno besedilo (651,15 KB)
Gradivo ima več datotek! Več...