The design of fuzzy controller for pulverized coal infection feedrate control in blast furnace

Maste

Lipopolysaccharide from prevotella nigrescens stimulates osteoclastogenesis in co-culture system but inhibits in bone marrow mononuclear cell culture

Thesis(master`s)--서울대학교 대학원 :치의학과 두개악안면세포 및 발생생물학전공,2004.Maste

Algebraic substructuring based eigenvalue reanalysis method for large-scale finite element models

In this paper, we propose an efficient eigenpair reanalysis method capable to solve large-scale finite element (FE) models. By applying the algebraic substructuring algorithm to the Craig-Bampton (CB) method, the resulting formulation of the reduced matrices is provided in a form of very tiny submatrix computation. And, to control the reduced matrices to more compact size while maintaining accuracy, the interface subspace reduction is applied subsequently. An automatic updating strategy is proposed, and it can give a recognition of which submatrices are revised in the new FE model. Thus, by using this algorithm, a reduced model corresponding to the new FE model is constructed very effectively. This is the core idea of the proposed method that can efficiently compute new eigenpairs, with small computation time. Several real engineering problems are considered to verify the performance of the proposed method in terms of computation time and computer memory.1. Introduction 1 2. Exact eigenpair reanalysis procedure 3 3. Combined approximation (CA) method 4 4. Proposed eigenpair reanalysis procedure 6 1) Algebraic substructuring based CB method 6 2) Interface subspace reduction 12 3) Efficient updating of revisions to the initial reduced model 16 4) Computation of new eigenpairs 23 5. Application to real engineering examples 25 1) Design revising problem for a stiffened plate 26 2) Corrosion thickness updating for a hull structure of the LNG carrier 38 6. Conclusions 51 7. References 52Maste

전압-리프트 기법을 이용한 비대칭 하프-브리지 공진형 컨버터

학위논문(석사) - 한국과학기술원 : 전기및전자공학과, 2014.8, [ ii, 58p ]Today, IT industry is constantly growing such as internet and cloud computing service. According to the trends, the data center is expanded in the world and its power consumption is also increased. Therefore, high efficiency of data center is strongly required in order to solve environment problems such as global warming by increasing power consumption of data centers. The new structure ($480V_{AC}-48V_{DC}$) of data center is already presented in order to improve efficiency of data center by reducing the transmission stages. However, the structure requires a change of server power system from AC/DC server power system to DC/DC one. Efficiency of DC/DC server power system is lower than AC/DC server power system because of large conduction losses in primary-side. Because of that, total efficiency of $480V_{AC}-48V_{DC}$ is almost same to the conventional structure. The study of DC/DC server power system for high efficiency is strongly required in order to achieve high total efficiency of $480V_{AC}-48V_{DC}$ structure. Therefore, this paper proposes asymmetric Half-Bridge (HB) resonant converter for high efficiency of DC/DC server power system by using voltage-lift technique. Because the transformer in DC/DC server power system have large turns ratio by higher input voltage and the proposed converter is able to be optimally designed at nominal input voltage by narrow input voltage range, the primary conduction loss is significantly reduced. Because there are no additional switches, large additional loss of the switches can be also removed. Therefore, the proposed converter can be achieved high efficiency. In this paper, the circuit derivation, operation principle, relevant analysis and design example of the proposed converter are presented. Finally, the validity of this study is confirmed by the experimental results of prototype 300W (12V/25A) converters.한국과학기술원 : 전기및전자공학과