Improvements in meta-heuristic algorithms for minimum cost design of reinforced concrete rectangular sections under compression and biaxial bending

A numerical procedure is proposed in this paper for achieving the minimum cost design of reinforced concrete rectangular sections under compression and biaxial bending by using biologically-inspired meta-heuristic optimization algorithms. The problem formulation includes the costs of concrete, reinforcement and formwork, obtaining the detailed optimum design in which the section dimensions and the reinforcement correspond to values used in practice. The formulation has been simplified in order to reduce the computational cost while ensuring the rigor necessary to achieve safe designs. The numerical procedure includes the possibility of using high-strength concrete and several design constraints, such as mínimum reinforcement and limiting the neutral axis depth. Two numerical examples are presented, drawing comparisons between the results obtained by ACI318 and EC2 standards

The Blogosphere at a Glance — Content-Based Structures Made Simple

A network representation based on a basic wordoverlap similarity measure between blogs is introduced. The simplicity of the representation renders it computationally tractable, transparent and insensitive to representation-dependent artifacts. Using Swedish blog data, we demonstrate that the representation, in spite of its simplicity, manages to capture important structural properties of the content in the blogosphere. First, blogs that treat similar subjects are organized in distinct network clusters. Second, the network is hierarchically organized as clusters in turn form higher-order clusters: a compound structure reminiscent of a blog taxonomy

Use of commercial CFD software for assessing the performance of personal aerosol samplers

Accurate performance of personal aerosol samplers is critical for industrial hygienists\u27 successful efforts to protect workers. Performance assessments of personal samplers are necessarily conducted in controlled environments so unknown sources of variability will not influence the results. This is done in order that samplers may be used with confidence for monitoring workplace air quality. These performance evaluations are usually conducted in wind tunnels. However, recent advances in high-performance cluster computing---together with advanced flow modeling software---have made it possible to evaluate sampler performance with computer simulations. This was done in the current research. Simulations were conducted for air and particle behavior near the inlet of the GSP and IOM Inhalable aerosol samplers using a pre-verified commercial computational fluid dynamics (CFD) software package. Steady-state, 3-D simulations were conducted using the FLUENT CFD solver with renormalized group (RNG) theory applied to a k-&egr; turbulence model. Particle trajectories were calculated in a Lagrangian reference frame on the resulting velocity fields. Based on the particle trajectories, sampling efficiencies were calculated and were compared to those reported in the literature. They were found to have similar overall trends for particle sizes up to 40 mum. Using a correction factor, agreement was observed to be reasonable for most cases. It was concluded that CFD can be used to evaluate the performance of personal samplers

Miniaturized Resonator and Bandpass Filter for Silicon-Based Monolithic Microwave and Millimeter-Wave Integrated Circuits

© 2018 IEEE. © 2018 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.This paper introduces a unique approach for the implementation of a miniaturized on-chip resonator and its application for the first-order bandpass filter (BPF) design. This approach utilizes a combination of a broadside-coupling technique and a split-ring structure. To fully understand the principle behind it, simplified LC equivalent-circuit models are provided. By analyzing these models, guidelines for implementation of an ultra-compact resonator and a BPF are given. To further demonstrate the feasibility of using this approach in practice, both the implemented resonator and the filter are fabricated in a standard 0.13-μm (Bi)-CMOS technology. The measured results show that the resonator can generate a resonance at 66.75 GHz, while the BPF has a center frequency at 40 GHz and an insertion loss of 1.7 dB. The chip size of both the resonator and the BPF, excluding the pads, is only 0.012mm 2 (0.08 × 0.144 mm 2).Peer reviewe

[GAS TURBINE FUEL AND AIR CONTROL SYSTEM]

Advancement in power generation has tended to enhance the ability in producing a more efficient power especially in mass power generation. In producing an efficient power generation, fuel consumption is one of the major criteria that need to be enhanced. Recent advance in fuel flow control have the potential for a significant impact on the design and performance of modern gas turbine engine. Fuel flow control has the potential to enhance mixing of fluids, modify wake behavior and reduce drag. The need ofdesigning a efficient gas turbine fuel and air flow control has drive the author to make a first step in designing and improving the gas turbine fuel and air control system. As been mentioned before this requirement in heavy power generation are much important in agreater living for main kind. From this study and design author will go in-depth in real application ofcontrol system design. The definition of fuel and air control system that author adopt here is the used of the small modification (especially in steps response) to change the decision making or fuel and air consumption for the existing gas turbine available. The design will be base onDIDATEC TGT 1,5KW gas turbine (UTP). The design will be done byreal time data and linear time invariant system, also theoretical formulation that will be studied by author for the improvement project. The improvement design that been done by the author will be the implementation ofFuzzy Logic system , where this implementation have shown atremendous improvement and benefit especially in real time application with ambiguous decision making system. Author also will analyze and design others conventional control system such as PID controller and also Leadlag compensator design. The design of system will be done with the help of MATLAB andSIMULINK software for comparison and system implementation

Gyrodampers for large space structures

The problem of controlling the vibrations of a large space structures by the use of actively augmented damping devices distributed throughout the structure is addressed. The gyrodamper which consists of a set of single gimbal control moment gyros which are actively controlled to extract the structural vibratory energy through the local rotational deformations of the structure, is described and analyzed. Various linear and nonlinear dynamic simulations of gyrodamped beams are shown, including results on self-induced vibrations due to sensor noise and rotor imbalance. The complete nonlinear dynamic equations are included. The problem of designing and sizing a system of gyrodampers for a given structure, or extrapolating results for one gyrodamped structure to another is solved in terms of scaling laws. Novel scaling laws for gyro systems are derived, based upon fundamental physical principles, and various examples are given

Plasmonic devices based on transparent conducting oxides for near infrared applications

In the past decade, there have been many breakthroughs in the field of plasmonics and nanophotonics that have enabled optical devices with unprecedented functionalities. Even though remarkable demonstration of at photonic devices has been reported, constituent materials are limited to the noble metals such as gold (Au) and silver (Ag) due to their abundance of free electrons which enable the support of plasmon resonances in the visible range. With the strong demand for extension of the optical range of plasmonic applications, it is now a necessity to explore and develop alternative materials which can overcome intrinsic issues of noble metals such as integration challenges, considerable optical losses, and lack of tunability of their optical properties. As most promising alternative to noble metals, transparent conducting oxides (TCOs) have been proposed as a promising new class of plasmonic materials for the IR applications. The main objective of the thesis is to explore the various plasmonic devices based on TCOs in order to evaluate the capabilities of TCOs as alternative metallic component for plasmonic applications. By beginning with a discussion of the general (optical, electrical and morphological) properties of TCOs, we describe the demonstration of devices such as plasmonic resonator for bio-sensing and waveplate metasurfaces. In addition, we study the impact of TCOs to local antenna as epsilon-near-zero (ENZ) substrate. The technological importance of the IR range is apparent and growing, and as plasmonics develops a niche at these frequencies, I believe this study represents a scientific directive toward the quest to bring plasmonics into the IR

B-스플라인 과완비 체계를 이용한 비모수 베이즈 회귀 모형 연구

학위논문(박사) -- 서울대학교대학원 : 자연과학대학 통계학과, 2021.8. 이재용.본 학위 논문에서는 함수의 변화하는 부드러움을 추정하기 위해 LARK 모형을 확장한 “레비 적응 B-스플라인 회귀 모형” (LABS) 을 제안한다. 즉, 제안한 모형은 B-스플라인 기저들이 생성 커널로 갖는 LARK 모형이다. 제안한 모형은 B-스플라인 기저의 차수를 조정하면서 불연속하거나 최고점 등을 지닌 함수의 부드러움에 체계적으로 적응한다. 모의 실험들과 실제 자료 분석을 통해서 제안한 모형이 불연속점, 최고점, 곡선 부분을 모두 잘 추정하고 있음을 입증하고, 거의 모든 실험에서 최고의 성능을 발휘한다. 또한, B-스플라인 차수에 따라 LABS 모형의 평균 함수가 특정 베소프 공간에 존재하고, LABS 모형의 사전분포가 해당 베소프 공간에 상당히 넓은 받침을 갖는다는 것을 밝힌다. 추가적으로, 텐서곱 B-스플라인 기저를 도입하여 다차원 자료를 분석할 수 있는 LABS 모형을 개발한다. 제안한 모형을 “다차원 레비 적응 B-스플라인 회귀 모형” (MLABS) 이라고 명명한다. MLABS 모형은 회귀 및 분류 문제들에서 최신 모형들과 필적할만한 성능을 갖추고 있다. 특히, MLABS 모형이 저차원 회귀 문제들에서 최신 비모수 회귀 모형들보다 안정적이고 정확한 예측 능력을 지니고 있음을 실험들을 통해 보인다.In this dissertation, we propose the Lévy Adaptive B-Spline regression (LABS) model, an extension of the LARK models, to estimate functions with varying degrees of smoothness. LABS model is a LARK with B-spline bases as generating kernels. By changing the degrees of the B-spline basis, LABS can systematically adapt the smoothness of functions, i.e., jump discontinuities, sharp peaks, etc. Results of simulation studies and real data examples support that this model catches not only smooth areas but also jumps and sharp peaks of functions. The LABS model has the best performance in almost all examples. We also provide theoretical results that the mean function for the LABS model belongs to the specific Besov spaces based on the degrees of the B-spline basis and that the prior of the model has the full support on the Besov spaces. Furthermore, we develop a multivariate version of the LABS model by introducing tensor product of B-spline bases named Multivariate Lévy Adaptive B-Spline regression (MLABS). MLABS model has comparable performance on both regression and classification problems. Especially, empirical results demonstrate that MLABS has more stable and accurate predictive abilities than state-of-the-art nonparametric regression models in relatively low-dimensional data.1 Introduction 1 1.1 Nonparametric regression model 1 1.2 Literature Review 2 1.2.1 Literature review of nonparametric function estimation 2 1.2.2 Literature review of multivariate nonparametric regression 5 1.3 Outline 7 2 Bayesian nonparametric function estimation using overcomplete systems with B-spline bases 9 2.1 Introduction 9 2.2 Lévy adaptive regression kernels 11 2.3 Lévy adaptive B-spline regression 14 2.3.1 B-spline basis 15 2.3.2 Model specification 17 2.3.3 Support of LABS model 19 2.4 Algorithm 22 2.5 Simulation studies 25 2.5.1 Simulation 1 : DJ test functions 27 2.5.2 Simulation 2 : Smooth functions with jumps and peaks 30 2.6 Real data applications 35 2.6.1 Example 1: Minimum legal drinking age 35 2.6.2 Example 2: Bitcoin prices on Bitstamp 37 2.6.3 Example 3: Fine particulate matter in Seoul 39 2.7 Discussion 42 3 Bayesian multivariate nonparametric regression using overcomplete systems with tensor products of B-spline bases 43 3.1 Introduction 43 3.2 Multivariate Lévy adaptive B-spline regression 44 3.2.1 Model specifications 45 3.2.2 Comparisons between basis fucntions of MLABS and MARS 47 3.2.3 Posterior inference 50 3.2.4 Binomial regressions for MLABS 53 3.3 Simulation studies 55 3.3.1 Surface examples 58 3.3.2 Friedman's examples 60 3.4 Real data applications 63 3.4.1 Regression examples 64 3.4.2 Classification examples 66 3.5 Discussion 67 4 Concluding Remarks 70 A Appendix 72 A.1 Appendix for Chapter 2 72 A.1.1 Proof of Theorem 2.3.1 72 A.1.2 Proof of Theorem 2.3.2 75 A.1.3 Proof of Theorem 2.3.3 75 A.1.4 Full simulation results for Simulation 1 79 A.1.5 Derivation of the full conditionals for LABS 83 Bibliography 87 Abstract in Korean 95박