Embeddability of pseudoline arrangements and point configurations to Eucliean plane

The present thesis explores embeddability (realizability) properties of pseudoline arrangements, perhaps, the most important mathematical structures in computational geometry. The underlying theme is the use of combinatorial representation of arrangements vs. usual geometric representation to approach the embeddability problem. The combinatorial representation chosen is that of counterclockwise systems (CCsystems) introduced by D.E. Knuth in 1992. CC systems were defined as sets of ordered triples of points that incorporate and obey counterclockwise relations on points in the plane. If a CC system can arise from actual points in the plane, it is called realizable. Not all CC-systems are realizable in plane, since they are defined by axioms that involve at most five points. The most famous nonrealizable configuration on nine points corresponds to so-called theorem of Pappus, which is a legal CC-system. Any heuristic solution to realizability question is proven to be NP-hard. The primary goal of this thesis is to consider embeddings of CC-systems to the Euclidean plane and to exploit properties coherent to embeddable systems. As a major effort in this task we have developed and implemented algorithms (brute force as well as breadth-first search) for finding the convex hull of a CC-system and geometrically testing the realizability of the system using linear programming methods. Recently, Goodman, Pollack, Wenger, and Zamfirescu1 2 have proved two conjectures of Grunbaum, showing that any arrangement of pseudolines on 8 points in the plane can be embedded into a projective plane, and that there exists a universal topological projective plane in which every arrangement of pseudolines is stretchable (realizable). Thus, we have conducted our realizability tests on systems arising from 9 or more points. Pappus system mentioned above and other non-realizable extensions of it on more than 9 points were studied as well. We have also developed a graphical interface (Java application) for creating, dynamically updating, visualizing and storing CC-systems. Visual geometric embedding of a particular system point-by-point is another feature provided by this interface

Which factors help to determine the long-term response to first-line tyrosine kinase inhibitors in patients with metastatic renal cell carcinoma: A Turkish multi-centre study

Many developing countries lack access to recommended first-line treatments for metastatic renal cell carcinoma (mRCC), such as immune checkpoint inhibitors (ICIs) or ICI-tyrosine kinase inhibitor (TKI) combinations. As a result, predictive markers are necessary to identify patients who may benefit from single-agent TKIs for long-term response. This study aims to identify such parameters. This was a multi-centre, retrospective study of patients with mRCC who were undergoing first-line treatment with sunitinib or pazopanib. Patients who had been diagnosed with mRCC and had not experienced disease progression for 36 months or more were deemed to have achieved a long-term response. Predictive clinical and pathological characteristics of patients who did not experience long-term disease progression were investigated. A total of 320 patients from four hospitals were included in the study. The median age of the patients was 60 years (range 20-89 years). According to the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk classification, 109 patients were classified as having favourable risk and 211 were in the intermediate-poor risk group. The median progression-free survival (PFS) and overall survival (OS) for all patients were 12.5 months and 76.4 months, respectively. In the long-term responder’s group, the median PFS was 78.4 months. Among all patients, prior nephrectomy, the Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) <1, and the absence of brain metastasis were predictive factors for long-term response. For patients in the favourable risk group, the lack of brain metastasis was a predictor of long-term response. In the intermediate-poor risk group, prior nephrectomy and ECOG PS <1 were predictive factors for long-term response. Some individuals with mRCC may experience a durable response to TKIs. The likelihood of a long-term response can be determined by factors such as nephrectomy, ECOG PS < 1, and the absence of brain metastases

Assessment of the impact of COP decisions on biodiversity and ecosystems

The relevance of the study is conditioned by the fact that any anthropogenic load or economic activity has an impact on the functioning of natural ecosystems, as demonstrated by the widespread practice of oil palm expansion. The purpose of this study was to develop methods for assessing strategies that play an important role in strengthening measures to protect biodiversity and ecosystems in Africa and Latin America, considering the impact of the decisions of the United Nations Climate Change Conference. The study considers the materials of various international organisations on the problems of biodiversity related to climate crises, inefficient territorial planning, expansion of land for growing crops that deplete the soil or reduce the area of land needed to accommodate biota. The paper presents a sequence of steps to assess the impact of the decisions of the United Nations Climate Change Conference on biodiversity and ecosystems. The aspects of conservation of biodiversity and ecosystems in the context of the expansion of palm plantations are substantiated. The indicators of the ratio between the available land area for palm oil cultivation and the area threatening to reduce the biodiversity of Africa are analysed. Environmental solutions are substantiated, which correspond to the provisions of the United Nations Climate Change Conference in the context of biodiversity and ecosystem conservation, taking into account the expansion of large areas for palm plantations in Colombia. The practical significance of this study lies in the development of a methodology for the economic and mathematical assessment of the decisions of the United Nations Climate Change Conference, which affect the conservation of biodiversity and ecosystems, and are the driving mechanism in creating an effective control system for tracking oil palm plantations, territorial development with the least environmental losses and high economic efficienc

Infrared Flame Detection System Using Multiple Neural Networks

Abstract – A model for an infrared (IR) flame detection system using multiple artificial neural networks (ANN) is presented. The present work offers significant improvements over our previous design [1]. Feature extraction only in the relevant frequency band using joint time-frequency analysis yields an input to a series of conjugate-gradient (CG) method-based ANNs. Each ANN is trained to distinguish all hydrocarbon flames from a particular type of environmental nuisance and ambient noise. Signal saturation caused by the increased intensity of IR sources at closer distances is resolved by adjustable gain control. I

Distributed parallel computing using Navigational Programming

Message Passing (MP) and Distributed Shared Memory (DSM) are the two most common approaches to distributed parallel computing. MP is difficult to use, while DSM is not scalable. Performance scalability and ease of programming can be achieved at the same time by using navigational programming (NavP). This approach combines the advantages of MP and DSM, and it balances convenience and flexibility. Similar to MP, NavP suggests to its programmers the principle of pivot-computes and hence is efficient and scalable. Like DSM, NavP supports incremental parallelization and shared variable programming and is therefore easy to use. The implementation and performance analysis of real-world algorithms, namely parallel Jacobi iteration and parallel Cholesky factorization, presented in this paper support the claim that the NavP approach is better suited for general purpose parallel distributed programming than either MP or DSM. Key Words distributed parallel computing, navigational programming, message passing, distributed shared memory, incremental parallelization