Upper limit of radiation treatment portals in rectal cancer: Is it wise to keep using bony landmarks in the present era of 3D conformal treatment?

Background: This study aimed to compare the levels of L5-S1 interspace and the bifurcation of common iliac vessels on simulation images of rectal cancer patients to evaluate the adequacy of superior borders in conventional 2D planning for covering internal iliac vessels. Materials and methods: Simulation images of 236 rectal cancer patients who received neoadjuvant chemoradiation and surgery were analyzed. The images were retrieved from the radiation treatment database and included delineations of L5-S1 interspace and common iliac vessel bifurcation. Distances between these landmarks were measured. Results: Among the 236 patients, the majority had the common iliac artery bifurcation positioned above the L5-S1 interspace. Specifically, 78.3% of patients had the right common iliac bifurcation above L5-S1 interspace, with an average distance of 2.02 cm. For the left common iliac artery, 77.11% of patients had the bifurcation above L5-S1 interspace, with an average distance of 1.99 cm. Notably, there were cases where the bifurcations were not at the same level. Conclusion: Using the L5-S1 junction as the upper border of the treatment portal may result in missing proximal nodes at risk of metastases. However, further research is needed to determine the significance of failures above the L5-S1 interspace for justifying the inclusion of the common iliac artery bifurcation in the treatment portal

Плоское перемещение пятизвенного двуногого робота по поверхности с препятствиями в виде ступеней

Modeling the anthropomorphic robot movement is of great interest to researchers all over the world. At the same time, the movement control of a walking mechanism is always a high dimension challenge. The difficulty with the anthropomorphic robot control is also caused by the fact that such a mechanism has always a hybrid dynamics and represents a sequential change of two phases – the single support phase and the double support phase (phase of changing robot’s leg). At the single support phase and at another phase the behavior of the biped robot is described by a system of ordinary differential equations and by a system of linear algebraic equations, respectively.The task of biped robot movement control has been studied in detail for the case when the robot moves over the horizontal surface. Obstacles make the task significantly complicated. The paper considers the movement control of the biped robot over the surface that is a periodic alternation of horizontal sections and obstacles. The obstacles represent steps of the same height known. It is assumed that the lengths of horizontal sections and steps are known as well. The objective is to create a control that provides robot’s periodic movement over the specified surface according to inherent characteristics of a walking human.For the single support phase, the outputs are proposed, the equality of which to zero corresponds to the robot’s movement with a given set of characteristics. The paper presents the feedback controls that stabilize the proposed outputs for a finite amount of time. By choosing the feedback parameters, it is possible to adjust the stabilization time so that the outputs become equal to zero when reached the end of each step.It is shown that for the chosen control law, the problem of constructing the control of robot’s periodic movement is reduced to the solution of a nonlinear equation. In the paper, we discuss the approaches to solving this equation and present the results of numerical simulation.The results obtained can be used to solve the problem of providing control of the biped robot movement over the surfaces with obstacles of a more complicated shape.Modeling the anthropomorphic robot movement is of great interest to researchers all over the world. At the same time, the movement control of a walking mechanism is always a high dimension challenge. The difficulty with the anthropomorphic robot control is also caused by the fact that such a mechanism has always a hybrid dynamics and represents a sequential change of two phases – the single support phase and the double support phase (phase of changing robot’s leg). At the single support phase and at another phase the behavior of the biped robot is described by a system of ordinary differential equations and by a system of linear algebraic equations, respectively.The task of biped robot movement control has been studied in detail for the case when the robot moves over the horizontal surface. Obstacles make the task significantly complicated. The paper considers the movement control of the biped robot over the surface that is a periodic alternation of horizontal sections and obstacles. The obstacles represent steps of the same height known. It is assumed that the lengths of horizontal sections and steps are known as well. The objective is to create a control that provides robot’s periodic movement over the specified surface according to inherent characteristics of a walking human.For the single support phase, the outputs are proposed, the equality of which to zero corresponds to the robot’s movement with a given set of characteristics. The paper presents the feedback controls that stabilize the proposed outputs for a finite amount of time. By choosing the feedback parameters, it is possible to adjust the stabilization time so that the outputs become equal to zero when reached the end of each step.It is shown that for the chosen control law, the problem of constructing the control of robot’s periodic movement is reduced to the solution of a nonlinear equation. In the paper, we discuss the approaches to solving this equation and present the results of numerical simulation.The results obtained can be used to solve the problem of providing control of the biped robot movement over the surfaces with obstacles of a more complicated shape.Моделирование движений антропоморфных роботов представляет большой интерес для исследователей во всем мире. Вместе с тем, управление движением шагающего механизма – это всегда сложная задача большой размерности. Сложность управления антропоморфным роботом связана еще и с тем, что динамика такого механизма всегда гибридна и представляет собой последовательную смену двух фаз – фазы одноопорного движения и фазы перехода робота с одной ноги на другую. На фазе одноопорного движения поведение шагающего робота описывается системой обыкновенных дифференциальных уравнений, на фазе перехода – системой линейных алгебраических уравнений.Задача управления перемещением двуногого шагающего робота детально изучена для случая, когда робот совершает перемещение по горизонтальной поверхности. Наличие препятствий существенно усложняет задачу. В настоящей работе рассматривается проблема управления перемещением двуногого шагающего робота по поверхности, являющейся периодическим чередованием горизонтальных участков и препятствий. Препятствия представляют собой ступени одной и той же известной высоты. Длины горизонтальных участков и ступеней также предполагаются известными. Цель работы – построить управление, обеспечивающее периодическое движение робота по указанной поверхности в соответствии с характеристиками, присущими ходьбе человека.Для фазы одноопорного движения предложены выходы, равенство которых нулю отвечает движению робота с заданным набором характеристик. В работе построены управления в виде обратной связи, которые стабилизируют предложенные выходы за конечное время. За счет выбора параметров в обратной связи можно регулировать время стабилизации так, чтобы выходы становились равными нулю к концу каждого шага.Показано, что при выбранном законе управления задача построения периодического движения робота сводится к задаче решения нелинейного уравнения. В работе обсуждаются способы решения этого уравнения и приводятся результаты численного моделирования.Полученные в работе результаты могут быть использованы для решения задачи управления перемещением шагающих роботов по поверхностям с препятствиями более сложной формы

Beyond Drawing the Line: A Study of the Edge Structure of Boston\u27s Emerald Necklace

Landscapes are mosaics of patches and corridors which are formed by hills, different soils types, vegetation patchiness, natural disturbances and human activities. As humans have developed, the patches and corridors have become fragmented and edges have been created. These edges become the critical points of interaction for wildlife with their surroundings. This is especially true in urban areas where development has created harsh edge environments. This study investigates the edge structure of Olmsted\u27s Emerald Necklace to understand how edges can be designed to create habitat for wildlife in urban areas. The Emerald Necklace is located in Boston, MA and was designed in the 1800s by Frederick Law Olmsted. The Necklace is the first designed greenway and has been used as a model by many cities throughout the country. As such, the Emerald Necklace can be studied to gain insight into how the edges of an urban greenway can be designed to augment animal diversity in urban areas. The goal of the study is to provide design recommendations that can be used as a guide by landscape architects to maintain current urban greenways and to plan future ones. The study\u27s major findings suggest that plant and animal species vary along the park as per the original design. Additional findings show that there is no separation of spaces for people and animals along the Necklace which can lead to habitat disturbance. In addition eight design recommendations are suggested to improve the current conditions of the Emerald Necklace. Moreover the recommendations are not site specific and can be applied to other existing and future urban greenways. These include protecting existing habitat, using native plants and eradicating invasive species. The results and findings are discussed in further detail. Overall the Emerald Necklace is ecologically healthy and provides functions for both people and animals

Real-Time Voice Biometric Speaker Verification

Abstract. Automated speaker verification has been an area of increased research in the last few years, with a special interest in metric learning approaches that compute distances between speaker voiceprints. In this paper, three metric learning systems are built and compared in a one-shot speaker verification task using contrastive max-margin loss, triplet loss, and quadruplet loss. For all the models, spectrograms are created from speaker audio. Convolutional Neural Network embedding layers are trained to produce compact voiceprints that allow users to be distinguished using distance calculations. Performances of the three models were similar, but the model with the best EER used triplet loss in this experiment