다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

비만아 부모의 돌봄 경험: q 방법론

As companies strive to develop artefacts intended for services instead of traditional sell-off, new challenges in the product development process arise to promote continuous improvement and increasing market profits. This creates a focus on product life-cycle components as companies then make life-cycle commitments, where they are responsible for the function availability during the extent of the life-cycle, i.e. functional products. One of these life-cycle components is manufacturing; therefore, companies search for new approaches of success during manufacturability evaluation already in engineering design. Efforts have been done to support early engineering design, as this phase sets constraints and opportunities for manufacturing. These efforts have turned into design for manufacturing methods and guidelines. A further step to improve the life-cycle focus during early engineering design is to reuse results and use experience from earlier projects. However, because results and experiences created during project work are often not documented for reuse, only remembered by some people, there is a need for design support. Knowledge engineering (KE) is a methodology for creating knowledge-based systems, e.g. systems that enable reuse of earlier results and make available both explicit and tacit corporate knowledge, enabling the automated generation and evaluation of new engineering design solutions during early product development. There are a variety of KE-approaches, such as knowledge-based engineering, case-based reasoning and programming, which have been used in research to develop design for manufacturing methods and applications. There are, however, opportunities for research where several approaches and their interdependencies, to create a transparent picture of how KE can be used to support engineering design, are investigated. The aim of the research presented in this thesis is to create new methods for design for manufacturing, by using several approaches of KE, and find the beneficial and less beneficial aspects of these methods in comparison to each other and earlier research. This thesis presents methods and applications for design for manufacturing using KE. KE has been employed in several ways, namely rule-based, rule-, programmingand finite element analysis (FEA)-based, and ruleand plan-based, which are tested and compared with each other. Results show that KE can be used to generate information about manufacturing in several ways. The rule-based way is suitable for supporting life-cycle commitments, as engineering design and manufacturing can be integrated with maintenance and performance predictions during early engineering design, though limited to the firing of production rules. The rule-, programmingand FEA-based way can be used to integrate computer-aided design tools and virtual manufacturing for non-linear stress and displacement analysis. This way may also bridge the gap between engineering designers and computational experts, even though this way requires a larger effort to program than the rule-based. The ruleand planbased way can enable design for manufacturing in two fashions – based on earlier manufacturing plans and based on rules. Because earlier manufacturing plans, together with programming algorithms, can handle knowledge that may be more intricate to capture as rules, as opposed to the time demanding routine work that is often automated by means of rules, several opportunities for designing for manufacturing exist.

Methods and Applications

Geometry: shape, size, aspect ratio and orientation Flow Type: forced, natural, laminar, turbulent, internal, external Boundary: isothermal (Tw = constant) or isoflux (q̇w = constant) Fluid Type: viscous oil, water, gases or liquid metals Properties: all properties determined at film temperature Tf = (Tw + T∞)/2 Note: ρ and ν ∝ 1/Patm ⇒ see Q12-40 density: ρ ((kg/m) specific heat: Cp (J/kg ·K) dynamic viscosity: μ, (N · s/m) kinematic viscosity: ν ≡ μ/ρ (m/s) thermal conductivity: k, (W/m ·K) thermal diffusivity: α, ≡ k/(ρ · Cp) (m/s) Prandtl number: Pr, ≡ ν/α (−−) volumetric compressibility: β, (1/K)

Convection Heat Transfer

Materials, technological status, and fundamentals of PEM fuel cells – A review

Energy storage is important for the application of the discontinuous and unstable renewable energy. The CaO/Ca(OH)2 thermochemical system of high energy density and little heat lose is promising for thermal energy storage, yet the heat and mass transfer processes related to dehydration reaction needs further improvement and the regulation manner related to the hydration reaction needs further investigation. In this work, a hybrid indirect-direct reactor of the CaO/Ca(OH)2 system is proposed with the physicochemical model developed to study the dehydration and hydration processes under different operating and structural conditions, and five indicators are defined to evaluate the overall reaction performance. During the dehydration process, the reactant is indirectly heated by the electrical heater at the reactor outside wall and the reaction proceeds in radial direction which is mainly limited by the poor heat transfer, leading to low energy storage efficiency of 6.1 %. The increase of reactant thermal conductivity and application of high-thermal-conductivity porous channel greatly enhance the heat transfer leading to significant reduction of reaction time and increase of energy storage efficiency up to 25.63 %. During the hydration process, the gas mixture directly contacts and reacts with solid reactant and the reaction proceeds in axial direction with reaction region of “U” shape which is mainly restricted by the reaction equilibrium. The thermal power density and reaction temperature of the hydration process can be regulated by the inlet mass flow rate and the inlet steam mass fraction respectively. The increase of inlet mass flow rate and inlet steam mass fraction leads to higher heat exchange efficiency at the same reaction extent and shorter hydration reaction time. The present study demonstrates the superiority of the indirect-direct type reactor and the performance of which can be further improved by optimizing the geometrical and operating conditions. 

Numerical study of the dehydration and hydration processes of the Ca(OH)2/CaO system in an indirect-direct reactor

Semi-global matching (SGM) is a canonical depth estimation algorithm widely used in the fields of autonomous driving, 3D reconstruction, and SLAM. However, high complexity withholds its application in high-speed and low-power depth extraction scenarios, notably in IoT and edge devices. To tackle these problems, we propose a region-optimized SGM algorithm, which can alleviate memory consumption bottleneck and strike a balance among power dissipation, processing speed, and resource consumption. First, we design a fully parallel initial matching costs calculation architecture, which ensures synchronization of the left and right pixel stream. Then, a two-layer parallel two-stage pipeline structure (TPTP) calculates the cost aggregation in two directions (0° and 135°) to mitigate the high computational complexity. Finally, we adopt a LUT-based cosine sub-pixel interpolation architecture and a multi-directional parallel hole filling architecture (MPHF) to improve accuracy further in the disparity refinement process. The experimental results show that the proposed pixel-level pipeline architecture achieves a processing speed of 320 frames per second (fps) at 98MHz on the Stratix-IV FPGA device.

A 320 FPS Pixel-Level Pipelined Stereo Vision Accelerator with Regional Optimization and Multi-direction Hole Filling

In order to investigate pool boiling heat transfer characteristics of refrigerants on different surfaces, an experimental rig is established and verified in this study. The pool boiling heat transfer experiment is conducted with R134a at three saturation temperatures. Six surfaces with Ra roughness ranging from 0.133 to 5.742 μm and two types of wettability are tested in the study. The heat flux varies from 40 to 280 kW/m2. Experimental results indicate that higher roughness is favorable to boiling heat transfer. Shieldex coating on copper surfaces can deteriorate heat transfer by 20% approximately. Visualization analysis was carried out with a high-speed camera to study bubble behavior. A new-found mode of bubble departing was observed at lower heat flux. Besides, the data were correlated in the form of Rohsenow correlation, comparison and supplement are concluded based on data obtained in this study. 

Experimental determination of the role of roughness and wettability on pool-boiling heat transfer of refrigerant

The Semi-Global Matching (SGM) algorithms and their hardware accelerators, which emphasize stereo matching rather than occlusion filling, have been developed in the last few years. However, filling occlusions is indispensable for many real-world applications. This work presents a pixel-level pipeline architecture for the post-processing of SGM, which refines disparity through a left-right check, and multi-directional occlusion filling refinement. The hardware architecture based on optimization algorithms is on the Stratix-IV platform, and it consumes about 5720 LUTs, 12961 registers, and 2.15M bits of on-chip memory. The maximum working frequency can reach up to 95.15 MHz for the 640×480 resolution video and 128 disparity range with the power dissipation of 1.46 W and 320 frames per second processing speed.

Post-Processing Refinement for Semi-Global Matching Algorithm Based on Real-Time FPGA

This demonstration showcases a framework of visual quantification for image enhancement where multivariate Gaussian (MVG) models are trained to assess image visibility. The visibility of an image is depicted by statistical features such as the contrast energy of the gray channel, yellow-blue channel, and red-green channel, average saturation, and gradients. The predicted visibility scores are then applied to define adaptive histogram equalization clip parameters for image enhancement. Finally, the hardware architecture is implemented on an FPGA to demonstrate the results for real-time image enhancement.

Li Chen

Papers

Numerical study of the dehydration and hydration processes of the Ca(OH)2/CaO system in an indirect-direct reactor

A 320 FPS Pixel-Level Pipelined Stereo Vision Accelerator with Regional Optimization and Multi-direction Hole Filling

Experimental determination of the role of roughness and wettability on pool-boiling heat transfer of refrigerant

Post-Processing Refinement for Semi-Global Matching Algorithm Based on Real-Time FPGA

Live Demonstration: Supervised-learning-based Visual Quantification for Image Enhancement