scholarly journals Scaling Local Control to Large-Scale Topological Navigation

2020 ◽  
Author(s):  
Xiangyun Meng ◽  
Nathan Ratliff ◽  
Yu Xiang ◽  
Dieter Fox
Keyword(s):  
Local Control ◽  
Large Scale ◽  
Topological Navigation

Irrigation in the Medieval Islamic Fayyum: Local Control in a Large-Scale Hydraulic System

2012 ◽  
Vol 55 (1) ◽  
pp. 1-31 ◽  
Author(s):  
Yossef Rapoport ◽  
Ido Shahar
Keyword(s):  
Water Supply ◽  
Local Control ◽  
Water Allocation ◽  
Hydraulic System ◽  
Large Scale ◽  
Close Reading ◽  
Unique Case ◽  
Islamic Period ◽  
Distinctive Aspect

Abstract Because of the unique set of sources available, the Fayyum in Middle Egypt offers a unique case study of large-scale irrigation from antiquity to the Islamic period. A close reading of a cadastral survey of the province from 641/1243-4 shows that the distinctive aspect of the Islamic period was the local control of water supply and management. Drawing on the engineering experience of the villagers, water allocation and management in the gravity-fed canals of the Fayyum were in the hands of iqṭāʿ holders and tribal groups along the main canals, a pattern similar to that which pertained in mediaeval al-Andalus.

Large-scale analysis for treatment strategy according to genetic alterations of KRAS and DPC4 (SMAD4) genes in pancreatic ductal adenocarcinoma.

2015 ◽  
Vol 33 (3_suppl) ◽  
pp. 361-361
Author(s):  
Sang Hyun Shin ◽  
Song Cheol Kim ◽  
Ki Byung Song ◽  
Jae Hoon Lee ◽  
Dae Wook Hwang ◽  
...  
Keyword(s):  
Pancreatic Ductal Adenocarcinoma ◽  
Local Control ◽  
Systemic Therapy ◽  
Large Scale ◽  
Univariate Analysis ◽  
Genetic Alterations ◽  
Ductal Adenocarcinoma ◽  
Control Group ◽  
Ras Gene ◽  
Recurrence Patterns

361 Background: To investigate correlation of genetic alterations of pancreatic ductal adenocarcinoma (PDAC) with patients’ survival, recurrence patterns, and treatment for recurrent disease. Methods: We reviewed genetic alterations of major 4 genes (K-ras, DPC4, p53, and c-erbB-2) in 699 patients who underwent surgical resection, and correlated with clinical outcomes. Results: Median survival of all patients was 21.7 months, and 5-year survival rate was 20.4%. Alterational rates of each gene were as follows: K-ras, 48.3%; DPC4, 68.1%; p53, 40.8%; c-erbB-2, 14.0%. Mutation of K-ras and inactivation of DPC4 genes were associated with shorter patients’ survival in univariate analysis. In multivariate analysis, mutation of K-ras gene was independently correlated with patients’ survival (especially, GAT and TGT subtypes). Inactivated DPC4 gene had no independent correlation with overall survival, but it was strongly associated with distant metastasis following pancreatectomy. Survival after recurrence (SAR) was evaluated in subdivided groups according to DPC4 gene function (intact or loss)/recurrence patterns (locoregional or distant)/treatment options (local control or systemic therapy). In these 8 groups, patients in intact/locoregional/local control group showed the longest survival (24.2 months of median SAR), and intact/locoregional/systemic therapy and loss/distant/systemic therapy groups were associated with much shorter survival (9.5 and 9.2 months of median SAR, respectively). Conclusions: Assessment of genetic features of PDAC may assist in deciding targeted surveillance or treatment for primary as well as recurrent PDAC, and further studies for therapeutic strategies according to genetic analyses should be devised.

scholarly journals ERF-IMCS: An Efficient and Robust Framework with Image-Based Monte Carlo Scheme for Indoor Topological Navigation

2020 ◽  
Vol 10 (19) ◽  
pp. 6829
Author(s):  
Song Xu ◽  
Huaidong Zhou ◽  
Wusheng Chou
Keyword(s):  
Monte Carlo ◽  
Image Retrieval ◽  
Large Scale ◽  
Visual Localization ◽  
Global Localization ◽  
Localization Method ◽  
Perceptual Aliasing ◽  
Topological Localization ◽  
Global And Local ◽  
Topological Navigation

Conventional approaches to global localization and navigation mainly rely on metric maps to provide precise geometric coordinates, which may cause the problem of large-scale structural ambiguity and lack semantic information of the environment. This paper presents a scalable vision-based topological mapping and navigation method for a mobile robot to work robustly and flexibly in large-scale environment. In the vision-based topological navigation, an image-based Monte Carlo localization method is presented to realize global topological localization based on image retrieval, in which fine-tuned local region features from an object detection convolutional neural network (CNN) are adopted to perform image matching. The combination of image retrieval and Monte Carlo provide the robot with the ability to effectively avoid perceptual aliasing. Additionally, we propose an effective visual localization method, simultaneously employing the global and local CNN features of images to construct discriminative representation for environment, which makes the navigation system more robust to the interference of occlusion, translation, and illumination. Extensive experimental results demonstrate that ERF-IMCS exhibits great performance in the robustness and efficiency of navigation.

Three-Fraction Stereotactic Body Radiation Therapy for Isolated Liver Recurrence from Colorectal Cancer

2009 ◽  
Vol 95 (4) ◽  
pp. 449-454 ◽  
Author(s):  
Mi-Sook Kim ◽  
Jin-Kyu Kang ◽  
Chul Koo Cho ◽  
Chul Won Choi ◽  
Young Seok Seo ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Radiation Therapy ◽  
Liver Metastasis ◽  
Local Control ◽  
Large Scale ◽  
Stereotactic Body Radiation Therapy ◽  
Liver Tumors ◽  
Internal Target ◽  
Liver Recurrence ◽  
Stereotactic Body Radiation

Aims To determine the feasibility and efficacy of 3-fraction stereotactic body radiation therapy for isolated colorectal cancer liver metastases. Materials and methods Ten patients with isolated inoperable liver metastasis from colorectal cancer with progression after salvage chemotherapy underwent stereotactic body radiation therapy. Follow-up was 7–49 months (median, 12). Six patients had a solitary lesion and 4 patients had 2 lesions. Internal target volumes of metastatic liver tumors ranged from 3.4 to 271 ml. Stereotactic body radiation therapy doses ranged from 36 to 51 Gy and were administered in three fractions. All patients demonstrated disease progression despite chemotherapy prior to stereotactic body radiation therapy. Results Three-year overall survival and local control rates were 40% and 60%, respectively. Tumors with an internal target volume <100 ml showed better local control rate than larger tumors. No severe complication was attributed to the therapy. Conclusion Our study suggests the potential feasibility of stereotactic body radiation therapy for selected patients with colorectal cancer liver metastasis and no treatment option. The study showed that excellent local control was achieved in patients with a total tumor volume of <100 ml but failed to clarify the role of stereotactic body radiation therapy for larger tumors. Further large scale studies are needed to define the indications of such therapy.

scholarly journals Image-Guided Brachytherapy for Salvage Reirradiation: A Systematic Review

Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1226
Author(s):  
Sophie Bockel ◽  
Sophie Espenel ◽  
Roger Sun ◽  
Isabelle Dumas ◽  
Sébastien Gouy ◽  
...  
Keyword(s):  
Local Recurrence ◽  
Local Control ◽  
Large Scale ◽  
Salvage Surgery ◽  
Curative Intent ◽  
Suitable Alternative ◽  
Clinical Issue ◽  
Image Guided ◽  
Gynecological Malignancies ◽  
Grade 3

Background: Local recurrence in gynecological malignancies occurring in a previously irradiated field is a challenging clinical issue. The most frequent curative-intent treatment is salvage surgery. Reirradiation, using three-dimensional image-guided brachytherapy (3D-IGBT), might be a suitable alternative. We reviewed recent literature concerning 3D-IGBT for reirradiation in the context of local recurrences from gynecological malignancies. Methods: We conducted a large-scale literature research, and 15 original studies, responding to our research criteria, were finally selected. Results: Local control rates ranged from 44% to 71.4% at 2–5 years, and overall survival rates ranged from 39.5% to 78% at 2–5 years. Grade ≥3 toxicities ranged from 1.7% to 50%, with only one study reporting a grade 5 event. Results in terms of outcome and toxicities were highly variable depending on studies. Several studies suggested that local control could be improved with 2 Gy equivalent doses >40 Gy. Conclusion: IGBT appears to be a feasible alternative to salvage surgery in inoperable patients or patients refusing surgery, with an acceptable outcome for patients who have no other curative therapeutic options, however at a high cost of long-term grade ≥3 toxicities in some studies. We recommend that patients with local recurrence from gynecologic neoplasm occurring in previously irradiated fields should be referred to highly experienced expert centers. Centralization of data and large-scale multicentric international prospective trials are warranted. Efforts should be made to improve local control while limiting the risk of toxicities.

Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda
Keyword(s):  
Image Processing ◽  
Large Scale ◽  
Harvard College ◽  
Oak Ridge ◽  
Large Scale Structures ◽  
Short Period Comet ◽  
Short Period ◽  
Scale Structures ◽  
Harvard College Observatory ◽  
Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

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