Multiple convolutional neural network training for Bangla handwritten numeral recognition

Recognition of handwritten numerals has gained much interest in recent years due to its various application potentials. The progress of handwritten Bangla numeral is well behind Roman, Chinese and Arabic scripts although it is a major language in Indian subcontinent and is the first language of Bangladesh. Handwritten numeral classification is a high-dimensional complex task and existing methods use distinct feature extraction techniques and various classification tools in their recognition schemes. Recently, convolutional neural network (CNN) is found efficient for image classification with its distinct features. In this study, three different CNNs with same architecture are trained with different training sets and combined their decisions for Bangla handwritten numeral recognition. One CNN is trained with ordinary training set prepared from handwritten scan images; and training sets for other two CNNs are prepared with fixed (positive and negative, respectively) rotational angles of original images. The proposed multiple CNN based approach is shown to outperform other existing methods while tested on a popular Bangla benchmark handwritten dataset

A two-storage model for deteriorating items with holding cost under inflation and Genetic Algorithms

A deterministic inventory model has been developed for deteriorating items and Genetic Algorithms (GA) having a ramp type demands with the effects of inflation with two-storage facilities. The owned warehouse (OW) has a fixed capacity of W units; the rented warehouse (RW) has unlimited capacity. Here, we assumed that the inventory holding cost in RW is higher than those in OW. Shortages in inventory are allowed and partially backlogged and Genetic Algorithms (GA) it is assumed that the inventory deteriorates over time at a variable deterioration rate. The effect of inflation has also been considered for various costs associated with the inventory system and Genetic Algorithms (GA). Numerical example is also used to study the behaviour of the model. Cost minimization technique is used to get the expressions for total cost and other parameters

Two stage Indian food grain supply chain network transportation-allocation model

This paper investigates the food grain supply chain, transportation allocation problem of Indian Public Distribution System (PDS). The different activities of Indian food grain supply chain are procurements, storage, movement, transportation and distribution. We have developed a mixed integer nonlinear programming model (MINLP) to minimize the transportation, inventory and operational cost of shipping food grains from the cluster of procurement centers of producing states to the consuming state warehouses. A recently developed chemical reaction optimization (CRO) algorithm is used for testing the model which gives the superior computational performance compared to other metaheuristics

DETEKSI PENYAKIT GAGAL JANTUNG BERDASARKAN SINYAL EKG MENGGUNAKAN NAIVE BAYES

Abstrak Gagal jantung merupakan masalah kesehatan masayarakat yang banyak ditemukan dan menjadi salah satu penyakit yang sangat berbahaya. Resiko terkena penyakit ini sangat besar terjadi pada usia lanjut. Penelitian ini bertujuan untuk menganalisis seseorang terkena penyakit gagal jantung atau tidak terkena penyakit gagal jantung (normal). Sinyal EKG (ElektroKardioGram) merupakan data yang digunakan untuk mengtahui detak jantung seseorang yang akan diteliti. Sinyal EKG kemudian akan diperhalus menggunakan wavelet, kemudian akan diolah lagi dengan Metode Naive Bayes. Metode Naive Bayes digunakan dalam mengklasifikasi sinyal yang sudah di extraksi menjadi penentuan hasil akhir. Hasil prediksi dari Naive bayes mendapat akurasi 70% . Kata kunci : Gagal Jantung, Naive Bayes, EKG, wavele

비정상유동이 조류발전단지 배치최적화에 미치는 영향

학위논문(석사) -- 서울대학교대학원 : 공과대학 건설환경공학부, 2022.2. 황진환.Due to the global climate crisis and the air pollution, demand on the renewable energy is consequently increasing as one of the main efforts. Wind and solar energy are taking the lead on the renewable energy industry, and as of the next competitive resource, tidal power is estimated to have a huge potential, thanks to its high energy density and easily predictable characteristics. Tidal power has not reached the practical level yet, due to financial challenges. In terms of reducing the cost and reach the competitive level of LCOE, the power extraction should be maximized within the constraints by conducting layout optimization of the turbines deployed, hence, understanding, and predicting the algorithm for layout optimization is necessary. The layout optimization for the tidal turbine is somewhat sophisticated, due to the unsteady tidal current condition in the nature, hence previous studies have found the problem under the steady condition. However, since the unsteadiness is a critical feature of the tidal current, there needs a study on the distinctive optimization characteristics under the unsteady condition. This study aims to find the tidal turbine farm layout optimization problem under the simplified unsteady tidal current condition in the nature and identify if the tidal turbine farm layout optimization procedure under unsteady condition can converges to find the global optimum. A number of numerical experiments were handled during the study to find the general trend/pattern of convergence to the global optimum under the various unsteady condition, with variation in the amplitude and the direction. The study first demonstrated the difference in the wake profile and the energy production of a single turbine under steady & unsteady flow, to be used as the basic assumption when figuring out the characteristics of layout optimization procedure under unsteady condition. The study also demonstrated the insight of the optimized layout and the minimum velocity threshold that enables the optimization to converge to the globally optimized layout at a given tolerance under steady condition. Finally, generalization of the strategy for the tidal turbine farm layout optimization under the unsteady flow was presented by finding the difference in the optimization procedure between steady & unsteady flow. It has been discovered that optimal layout under unidirectional, unsteady flow condition is similar to the optimal layout under steady condition when it satisfies the minimum velocity threshold condition. However, optimal layout under bidirectional conditions was totally different to the optimal layout under unidirectional conditions, to consider the wake effect from both directions. Under the bidirectional flow condition, the turbines were found to be staggered with respect to each other in order to take advantage of local speedups between upwind turbines. The numerical experiments were performed with OpenTidalFarm, an open-source solver for specific PDE-constrained, gradient-based optimization problems, especially those related to tidal farm design. The simulation domain was described as a rectangular farm, PDE is given as two-dimensional nonlinear shallow water equations, total power output is the target functional to be maximized, and turbine was parameterized as a bump function. Adjoint method was used as to compute the gradient for the optimization problem.세계적인 기후 위기와 대기 오염으로 인해, 재생 에너지에 대한 수요가 증가하고 있다. 풍력과 태양광 발전이 신재생에너지 산업을 선도하고 있으며, 조류 발전은 높은 에너지 밀도와 예측 가능한 특성으로 인해 앞으로의 잠재력이 클 것으로 추정된다. 조류 발전은 아직 가격 경쟁의 측면에서 실용화 수준에 이르지 못했다. 가격 경쟁력을 확보하기 위한 비용절감의 수단으로는 전력 추출 극대화를 위한 노력이 필요하며, 이에 제약 조건 내에서의 터빈 배치 최적화를 위한 알고리즘에 대한 이해가 선행되어야 한다. 조류발전 단지 배치 최적화에 대한 연구는 기존에 다수 진행되어 왔으나, 비정상 유동에서의 최적화 해를 도출하는 것이 다소 복잡해 정상유동 상태의 가정이 주를 이루었다. 그러나, 조류는 달과 태양의 기조력에 의한 조류에 의해 발생하는 현상임에 따라, 비정상 유동이라는 특성이 크게 작용하는 바, 본 연구에서는 이러한 특성을 반영한 배치 최적화 연구가 진행되었다. 따라서 본 연구는 비정상 유동 하에서의 조류발전단지 배치 최적화에 관한 이해를 기반으로 이 때의 민감도 기반 최적화의 해가 전역 최적해에 수렴하는가를 수치실험을 통해 확인하는 것을 목적으로 하였다. 다양한 진폭과 방향 등의 조건에서 수백개의 수치실험이 이루어졌으며 이를 통해 비정상 유동 하에서의 조류발전단지 배치 최적화에 대한 일반적인 추세와 최적해를 확인하였다. 먼저, 정상 유동과 비정상 유동 각각에 단일 터빈을 두어 각 조건 하에서의 후류 형태와 에너지 생산량 차이를 확인하였다. 또한 정상 유동 하에서의 최적 배치 형태와 최적해에 도달할 수 있는 임계 속도 값을 도출하여 비정상 유동 하에서의 수치실험에 선행 가정으로 사용될 수 있도록 하였다. 이러한 실험 결과들을 바탕으로 비정상 유동 하에서의 조류발전단지 배치 최적화에 대한 일반적인 추세와 최적해를 확인할 수 있었다. 비정상 단방향 유동의 경우에는 임계 속도 조건을 만족하였을 때 정상 유동 하에서의 최적 배치와 비슷한 형태를 보였지만, 비정상 양방향 유동의 경우에는 터빈이 교차 배치된 형태를 최적 배치로 갖는 것을 알 수 있었다. 수치실험에는 파이썬 기반 오픈소스 소프트웨어인 OpenTidal Farm이 사용되었다. 수치실험은 직사각형 조류발전 단지 내에서 이루어졌으며, 편미분 방정식은 2차원 천수방정식을 사용했고, 목적함수는 총에너지 추출량으로 구성되었다. 또한, 터빈은 민감도 기반 최적화에 적합하게끔 범프함수로 매개변수화 되어 실험에 사용되었다.ABSTRACT i TABLE OF CONTENTS iv List of Figures vii List of Symbol xi CHAPTER 1. INTRODUCTION 1 1.1 General introduction 1 1.2 Objective 2 CHAPTER 2. THEORETICAL BACKGROUDS 7 2.1 General evolution of the renewable energy 7 2.2 Tidal turbine farm 10 2.2.1 The physics of tide 10 2.2.2 The physics of tidal currents - unsteadiness 13 2.2.3 Tidal turbine 15 2.2.4 Tidal energy resources in Korea 17 2.3 Shallow water equation (SWE) 19 2.4 Gradient-based optimization using adjoint method 21 2.4.1 Problem formulation 22 2.4.2 The adjoint method 22 CHAPTER 3. METHODOLOGY 25 3.1 Numerical model description 25 3.1.1 The design parameters 25 3.1.2 The PDE constraints 25 3.1.3 The turbine parameterization 26 3.1.4 The functional of interest 27 3.1.5 Box and inequality constraints 27 3.1.6 Optimization algorithm 28 3.2 Experiment overview 29 3.2.1 Experiment procedure 29 3.2.2 Experimental flow chart 31 3.3 Simulation set-up 31 3.3.1 Mesh domain 31 3.3.2 Boundary condition 33 3.3.3 Parameter settings 36 CHAPTER 4. Test cases, Results and Discussions 39 4.1 Pilot Test 1: Steady & Unsteady flow impact on a single turbine 39 4.1.1 Wake behavior 39 4.1.2 comparison criterion between steady and unsteady flow based on the energy production 46 4.1.3 Conclusion of Pilot test 1 48 4.2 Pilot Test 2: Minimum velocity threshold (MVT) to converge to QGO and the concept of the optimized layout 49 4.2.1 Test cases 49 4.2.2 Finding minimum threshold of velocity (MVT) 51 4.2.3 Insights on the optimized layout 55 4.2.4 Conclusion of Pilot test 2 57 4.3 Main test: Effect of unsteadiness in the optimization procedure compared to the steady condition 59 4.3.1 Test cases 59 4.3.2 Optimal layout for each flow conditions 62 4.3.3 Strategy to obtain QGO for bidirectional flow condition 70 4.3.4 Conclusion of Main test 71 CHAPTER 5. Conclusions 73 REFERENCES 76 국문초록 80석