An application of improved salp swarm algorithm for optimal power flow solution considering stochastic solar power generation

This paper describes the use of an improved version of the Salp Swarm Algorithm, known as iSSA, to address Optimal Power Flow (OPF) issues in power system management. The iSSA is applied to OPF problems involving stochastic solar power generation, with the goal of optimizing control variables such as real power generation, voltage magnitude at generation buses, transformer tap settings, and reactive power compensation. The optimization aims to achieve three objectives: minimizing power loss, minimizing cost, and minimizing combined cost and emissions from power generation. The iSSA's performance was tested on a modified IEEE 30-bus system and compared to other recent algorithms, including SSA. The simulation results show that the iSSA outperformed all compared algorithms for all objective functions that have been derived in this study

Performance Analysis of Tree Seed Algorithm for Small Dimension Optimization Functions

Tree-Seed Algorithm (TSA) simulates the growth of trees and seeds on a land. TSA is a method proposed to solve continuous optimization problems. Trees and seeds indicate possible solutions in the search space for optimization problems. Trees are planted in the ground at the beginning of the search and each tree produces several seeds during iterations. While the trees were selected randomly during seed formation, the tournament selection method was used and also hybridized by adding the C parameter, which is the acceleration coefficient calculated according to the size of the problem. In this study, continuous optimization problem has been solved by the hybrid method. First, the performance analyses of the five best known numerical benchmark functions have been done, in both TSA and hybrid method TSA with 2, 3, 4 and 5 dimensions, and 10-50 population numbers. After that, well-known algorithms in the literature like Particle Swarm Optimization (PSO), TSA, Artificial Bee Colony (ABC), Harmony Search (HS), as well as hybrid method TSA (HTSA) have been applied to twenty-four numerical benchmark functions and the performance analyses of algorithms have been done. Hopeful and comparable conclusions based on solution quality and robustness can be obtained with the hybrid method

Improved Optimal Power Flow for a Power System Incorporating Wind Power Generation by Using Grey Wolf Optimizer Algorithm

In this paper, an efficient Grey Wolf Optimizer (GWO) search algorithm is presented for solving the optimal power flow problem in a power system, enhanced by wind power plant. The GWO algorithm is based on meta-heuristic method, and it has been proven to give very competitive results in different optimization problems. First, by using the proposed technique, the system independent variables such as the generators’ power outputs as well as the associated dependent variables like the bus voltage magnitudes, transformer tap setting and shunt VAR compensators values are optimized to meet the power system operation requirements. The Optimal power flow study is then performed to assess the impact of variable wind power generation on system parameters. Two standard power systems IEEE30 and IEEE57 are used to test and verify the effectiveness of the proposed GWO method. The obtained results are then compared with others given by available optimization methods in the literature. The outcome of the comparison proved the superiority of the GWO algorithm over other meta-heuristics techniques such as Modified Differential Evolution (MDE), Enhanced Genetic Algorithm (EGA), Particle Swarm Optimization (PSO), Biogeography Based Optimization (BBO), Artificial Bee Algorithm (ABC) and Tree-Seed Algorithm (TSA)

An effective solution to the optimal power flow problem using meta-heuristic algorithms

Financial loss in power systems is an emerging problem that needs to be resolved. To tackle the mentioned problem, energy generated from various generation sources in the power network needs proper scheduling. In order to determine the best settings for the control variables, this study formulates and solves an optimal power flow (OPF) problem. In the proposed work, the bird swarm algorithm (BSA), JAYA, and a hybrid of both algorithms, termed as HJBSA, are used for obtaining the settings of optimum variables. We perform simulations by considering the constraints of voltage stability and line capacity, and generated reactive and active power. In addition, the used algorithms solve the problem of OPF and minimize carbon emission generated from thermal systems, fuel cost, voltage deviations, and losses in generation of active power. The suggested approach is evaluated by putting it into use on two separate IEEE testing systems, one with 30 buses and the other with 57 buses. The simulation results show that for the 30-bus system, the minimization in cost by HJBSA, JAYA, and BSA is 860.54 $/h, 862.31,$/h and 900.01 $/h, respectively, while for the 57-bus system, it is 5506.9$/h, 6237.4, $/h and 7245.6$/h for HJBSA, JAYA, and BSA, respectively. Similarly, for the 30-bus system, the power loss by HJBSA, JAYA, and BSA is 9.542 MW, 10.102 MW, and 11.427 MW, respectively, while for the 57-bus system, the value of power loss is 13.473 MW, 20.552, MW and 18.638 MW for HJBSA, JAYA, and BSA, respectively. Moreover, HJBSA, JAYA, and BSA cause reduction in carbon emissions by 4.394 ton/h, 4.524, ton/h and 4.401 ton/h, respectively, with the 30-bus system. With the 57-bus system, HJBSA, JAYA, and BSA cause reduction in carbon emissions by 26.429 ton/h, 27.014, ton/h and 28.568 ton/h, respectively. The results show the outperformance of HJBSA

Evolutionary Computation 2020

Intelligent optimization is based on the mechanism of computational intelligence to refine a suitable feature model, design an effective optimization algorithm, and then to obtain an optimal or satisfactory solution to a complex problem. Intelligent algorithms are key tools to ensure global optimization quality, fast optimization efficiency and robust optimization performance. Intelligent optimization algorithms have been studied by many researchers, leading to improvements in the performance of algorithms such as the evolutionary algorithm, whale optimization algorithm, differential evolution algorithm, and particle swarm optimization. Studies in this arena have also resulted in breakthroughs in solving complex problems including the green shop scheduling problem, the severe nonlinear problem in one-dimensional geodesic electromagnetic inversion, error and bug finding problem in software, the 0-1 backpack problem, traveler problem, and logistics distribution center siting problem. The editors are confident that this book can open a new avenue for further improvement and discoveries in the area of intelligent algorithms. The book is a valuable resource for researchers interested in understanding the principles and design of intelligent algorithms

Traffic data based ideal airport suggestions providing regional service in disasters

Bu çalışma, önceki benzer çalışmalardan üç ana yönden ayrılmaktadır. Birincisi, yöntem olarak diğerlerinden ayrılarak ülke çapında sadece tek bir lokasyondaki havalimanı tesisi değil kümeleme yöntemi uygulanarak bölgesel hizmet verebilecek en uygun tesisler tespit edilmiştir. İkincisi, önceki çalışmalarda İstanbul Havalimanı henüz hizmete girmediğinden dolayı değerlendirmeye alınmamışken, bu çalışmada optimizasyon hesaplarına dahil edilmiştir. Üçüncüsü, yeni durumun önceki çalışmalara nazaran daha güncel verilerle ve daha güncel bir optimizasyon yöntemi olan ağaç tohum algoritması kullanılarak optimum çözümler üretilmiştir. Trafik verileri, trafiğe dayalı ağırlık katsayıları ve ulaşım mesafelerinin elde edildiği konum verilerine dayanarak yapılan analizler sonucunda, toplam on altı havalimanı kendi bölgelerine, özellikle herhangi bir felaket sırasında veya sonrasındaki acil durumlarda, servis sağlayabilecek ideal havalimanları bu çalışmada ortaya çıkarılarak tavsiye edilmiştir. Bu araştırmanın önerileri doğrultusunda, herhangi bir acil durumda gerekli olan ve havayolu ile sağlanabilecek hizmetler sayesinde zaman ve gider kaybının azaltılması gibi amaçlar gözetilirken daha da önemlisi can kaybının en az düzeye indirilmesi konusunda ilerleme kaydedilmesi beklenmektedir.This study differs from previous similar studies in three main directions. Firstly, the location of the most suitable facilities that can provide regional service were determined by applying clustering method. Thus, not only one airport facility in a single location serving across the country was determined, which separates this research from the others. Secondly, in the previous studies, Istanbul Airport was not taken into account because it has not been put into service. Therefore, this study takes that particular airport into consideration. Thirdly, optimum solutions for such new situation were produced with more up-to-date data and using a modern optimization method, the tree seed algorithm. As a result of the analyzes made based on traffic data, traffic-based weight coefficients and location data from which transportation distances were obtained, a total of sixteen ideal airports were recommended that can provide service to their regions, especially during emergencies or after any disaster. In accordance with the suggestions of this research, it is expected that progress will be made in minimizing the loss of time and expense, and especially minimizing the loss of life thanks to the services which can be provided by air transportation in any emergency.No sponso

복부 CT에서 간과 혈관 분할 기법

학위논문(박사)--서울대학교 대학원 :공과대학 컴퓨터공학부,2020. 2. 신영길.복부 전산화 단층 촬영 (CT) 영상에서 정확한 간 및 혈관 분할은 체적 측정, 치료 계획 수립 및 추가적인 증강 현실 기반 수술 가이드와 같은 컴퓨터 진단 보조 시스템을 구축하는데 필수적인 요소이다. 최근 들어 컨볼루셔널 인공 신경망 (CNN) 형태의 딥 러닝이 많이 적용되면서 의료 영상 분할의 성능이 향상되고 있지만, 실제 임상에 적용할 수 있는 높은 일반화 성능을 제공하기는 여전히 어렵다. 또한 물체의 경계는 전통적으로 영상 분할에서 매우 중요한 요소로 이용되었지만, CT 영상에서 간의 불분명한 경계를 추출하기가 어렵기 때문에 현대 CNN에서는 이를 사용하지 않고 있다. 간 혈관 분할 작업의 경우, 복잡한 혈관 영상으로부터 학습 데이터를 만들기 어렵기 때문에 딥 러닝을 적용하기가 어렵다. 또한 얇은 혈관 부분의 영상 밝기 대비가 약하여 원본 영상에서 식별하기가 매우 어렵다. 본 논문에서는 위 언급한 문제들을 해결하기 위해 일반화 성능이 향상된 CNN과 얇은 혈관을 포함하는 복잡한 간 혈관을 정확하게 분할하는 알고리즘을 제안한다. 간 분할 작업에서 우수한 일반화 성능을 갖는 CNN을 구축하기 위해, 내부적으로 간 모양을 추정하는 부분이 포함된 자동 컨텍스트 알고리즘을 제안한다. 또한, CNN을 사용한 학습에 경계선의 개념이 새롭게 제안된다. 모호한 경계부가 포함되어 있어 전체 경계 영역을 CNN에 훈련하는 것은 매우 어렵기 때문에 반복되는 학습 과정에서 인공 신경망이 스스로 예측한 확률에서 부정확하게 추정된 부분적 경계만을 사용하여 인공 신경망을 학습한다. 실험적 결과를 통해 제안된 CNN이 다른 최신 기법들보다 정확도가 우수하다는 것을 보인다. 또한, 제안된 CNN의 일반화 성능을 검증하기 위해 다양한 실험을 수행한다. 간 혈관 분할에서는 간 내부의 관심 영역을 지정하기 위해 앞서 획득한 간 영역을 활용한다. 정확한 간 혈관 분할을 위해 혈관 후보 점들을 추출하여 사용하는 알고리즘을 제안한다. 확실한 후보 점들을 얻기 위해, 삼차원 영상의 차원을 먼저 최대 강도 투영 기법을 통해 이차원으로 낮춘다. 이차원 영상에서는 복잡한 혈관의 구조가 보다 단순화될 수 있다. 이어서, 이차원 영상에서 혈관 분할을 수행하고 혈관 픽셀들은 원래의 삼차원 공간상으로 역 투영된다. 마지막으로, 전체 혈관의 분할을 위해 원본 영상과 혈관 후보 점들을 모두 사용하는 새로운 레벨 셋 기반 알고리즘을 제안한다. 제안된 알고리즘은 복잡한 구조가 단순화되고 얇은 혈관이 더 잘 보이는 이차원 영상에서 얻은 후보 점들을 사용하기 때문에 얇은 혈관 분할에서 높은 정확도를 보인다. 실험적 결과에 의하면 제안된 알고리즘은 잘못된 영역의 추출 없이 다른 레벨 셋 기반 알고리즘들보다 우수한 성능을 보인다. 제안된 알고리즘은 간과 혈관을 분할하는 새로운 방법을 제시한다. 제안된 자동 컨텍스트 구조는 사람이 디자인한 학습 과정이 일반화 성능을 크게 향상할 수 있다는 것을 보인다. 그리고 제안된 경계선 학습 기법으로 CNN을 사용한 영상 분할의 성능을 향상할 수 있음을 내포한다. 간 혈관의 분할은 이차원 최대 강도 투영 기반 이미지로부터 획득된 혈관 후보 점들을 통해 얇은 혈관들이 성공적으로 분할될 수 있음을 보인다. 본 논문에서 제안된 알고리즘은 간의 해부학적 분석과 자동화된 컴퓨터 진단 보조 시스템을 구축하는 데 매우 중요한 기술이다.Accurate liver and its vessel segmentation on abdominal computed tomography (CT) images is one of the most important prerequisites for computer-aided diagnosis (CAD) systems such as volumetric measurement, treatment planning, and further augmented reality-based surgical guide. In recent years, the application of deep learning in the form of convolutional neural network (CNN) has improved the performance of medical image segmentation, but it is difficult to provide high generalization performance for the actual clinical practice. Furthermore, although the contour features are an important factor in the image segmentation problem, they are hard to be employed on CNN due to many unclear boundaries on the image. In case of a liver vessel segmentation, a deep learning approach is impractical because it is difficult to obtain training data from complex vessel images. Furthermore, thin vessels are hard to be identified in the original image due to weak intensity contrasts and noise. In this dissertation, a CNN with high generalization performance and a contour learning scheme is first proposed for liver segmentation. Secondly, a liver vessel segmentation algorithm is presented that accurately segments even thin vessels. To build a CNN with high generalization performance, the auto-context algorithm is employed. The auto-context algorithm goes through two pipelines: the first predicts the overall area of a liver and the second predicts the final liver using the first prediction as a prior. This process improves generalization performance because the network internally estimates shape-prior. In addition to the auto-context, a contour learning method is proposed that uses only sparse contours rather than the entire contour. Sparse contours are obtained and trained by using only the mispredicted part of the network's final prediction. Experimental studies show that the proposed network is superior in accuracy to other modern networks. Multiple N-fold tests are also performed to verify the generalization performance. An algorithm for accurate liver vessel segmentation is also proposed by introducing vessel candidate points. To obtain confident vessel candidates, the 3D image is first reduced to 2D through maximum intensity projection. Subsequently, vessel segmentation is performed from the 2D images and the segmented pixels are back-projected into the original 3D space. Finally, a new level set function is proposed that utilizes both the original image and vessel candidate points. The proposed algorithm can segment thin vessels with high accuracy by mainly using vessel candidate points. The reliability of the points can be higher through robust segmentation in the projected 2D images where complex structures are simplified and thin vessels are more visible. Experimental results show that the proposed algorithm is superior to other active contour models. The proposed algorithms present a new method of segmenting the liver and its vessels. The auto-context algorithm shows that a human-designed curriculum (i.e., shape-prior learning) can improve generalization performance. The proposed contour learning technique can increase the accuracy of a CNN for image segmentation by focusing on its failures, represented by sparse contours. The vessel segmentation shows that minor vessel branches can be successfully segmented through vessel candidate points obtained by reducing the image dimension. The algorithms presented in this dissertation can be employed for later analysis of liver anatomy that requires accurate segmentation techniques.Chapter 1 Introduction 1 1.1 Background and motivation 1 1.2 Problem statement 3 1.3 Main contributions 6 1.4 Contents and organization 9 Chapter 2 Related Works 10 2.1 Overview 10 2.2 Convolutional neural networks 11 2.2.1 Architectures of convolutional neural networks 11 2.2.2 Convolutional neural networks in medical image segmentation 21 2.3 Liver and vessel segmentation 37 2.3.1 Classical methods for liver segmentation 37 2.3.2 Vascular image segmentation 40 2.3.3 Active contour models 46 2.3.4 Vessel topology-based active contour model 54 2.4 Motivation 60 Chapter 3 Liver Segmentation via Auto-Context Neural Network with Self-Supervised Contour Attention 62 3.1 Overview 62 3.2 Single-pass auto-context neural network 65 3.2.1 Skip-attention module 66 3.2.2 V-transition module 69 3.2.3 Liver-prior inference and auto-context 70 3.2.4 Understanding the network 74 3.3 Self-supervising contour attention 75 3.4 Learning the network 81 3.4.1 Overall loss function 81 3.4.2 Data augmentation 81 3.5 Experimental Results 83 3.5.1 Overview 83 3.5.2 Data configurations and target of comparison 84 3.5.3 Evaluation metric 85 3.5.4 Accuracy evaluation 87 3.5.5 Ablation study 93 3.5.6 Performance of generalization 110 3.5.7 Results from ground-truth variations 114 3.6 Discussion 116 Chapter 4 Liver Vessel Segmentation via Active Contour Model with Dense Vessel Candidates 119 4.1 Overview 119 4.2 Dense vessel candidates 124 4.2.1 Maximum intensity slab images 125 4.2.2 Segmentation of 2D vessel candidates and back-projection 130 4.3 Clustering of dense vessel candidates 135 4.3.1 Virtual gradient-assisted regional ACM 136 4.3.2 Localized regional ACM 142 4.4 Experimental results 145 4.4.1 Overview 145 4.4.2 Data configurations and environment 146 4.4.3 2D segmentation 146 4.4.4 ACM comparisons 149 4.4.5 Evaluation of bifurcation points 154 4.4.6 Computational performance 159 4.4.7 Ablation study 160 4.4.8 Parameter study 162 4.5 Application to portal vein analysis 164 4.6 Discussion 168 Chapter 5 Conclusion and Future Works 170 Bibliography 172 초록 197Docto

Operational progression of digital soil assessment for agricultural growth in Tasmania, Australia

Tasmania, Australia, is currently undergoing a period of agricultural expansion through the development of new irrigation schemes across the State, primarily to stimulate the economy and ensure future food security. ‘Operational Progression of Digital Soil Assessment (DSA) for Agricultural Growth in Tasmania, Australia’ presents the adaptation and operationalisation of quantitative approaches for regional land evaluation within these schemes, specifically applied Digital Soil Mapping (DSM) to inform a land suitability evaluation for 20 different agricultural crops, and ultimately a spatial indication of the State’s agricultural versatility and capital. DSM had not previously been applied or tested in Tasmania; the research examines and validates DSM approaches with respect to the State’s unique and complex soils and biophysical interactions with climate and terrain, and how these apply to various agricultural land uses. The thesis is a major contribution to the methodology and development of one of the first major operational DSA programs in Australia, and forms a framework for this type of DSM approach to be used in future operational land evaluation elsewhere