Enhanced magnetic and thermoelectric properties in epitaxial polycrystalline SrRuO3 thin film

Transition metal oxide thin films show versatile electrical, magnetic, and thermal properties which can be tailored by deliberately introducing macroscopic grain boundaries via polycrystalline solids. In this study, we focus on the modification of the magnetic and thermal transport properties by fabricating single- and polycrystalline epitaxial SrRuO3 thin films using pulsed laser epitaxy. Using epitaxial stabilization technique with atomically flat polycrystalline SrTiO3 substrate, epitaxial polycrystalline SrRuO3 thin film with crystalline quality of each grain comparable to that of single-crystalline counterpart is realized. In particular, alleviated compressive strain near the grain boundaries due to coalescence is evidenced structurally, which induced enhancement of ferromagnetic ordering of the polycrystalline epitaxial thin film. The structural variations associated with the grain boundaries further reduce the thermal conductivity without deteriorating the electronic transport, and lead to enhanced thermoelectric efficiency in the epitaxial polycrystalline thin films, compared with their single-crystalline counterpart.Comment: 24 pages, 5 figure

Enhanced magnetic and thermoelectric properties in epitaxial polycrystalline SrRuO3 thin film

Transition metal oxide thin films show versatile electrical, magnetic, and thermal properties which can be tailored by deliberately introducing macroscopic grain boundaries via polycrystalline solids. In this study, we focus on the modification of the magnetic and thermal transport properties by fabricating single- and polycrystalline epitaxial SrRuO3 thin films using pulsed laser epitaxy. Using epitaxial stabilization technique with atomically flat polycrystalline SrTiO3 substrate, epitaxial polycrystalline SrRuO3 thin film with crystalline quality of each grain comparable to that of single-crystalline counterpart is realized. In particular, alleviated compressive strain near the grain boundaries due to coalescence is evidenced structurally, which induced enhancement of ferromagnetic ordering of the polycrystalline epitaxial thin film. The structural variations associated with the grain boundaries further reduce the thermal conductivity without deteriorating the electronic transport, and lead to enhanced thermoelectric efficiency in the epitaxial polycrystalline thin films, compared with their single-crystalline counterpart.Comment: 24 pages, 5 figure

AUTOSAR 런타임 환경 및 베이직 소프트웨어 테스트 방법에 관한 연구

Automotive software is increasingly becoming more complex but the development period is becoming shorter. Most vehicle manufacturers are carrying out development using a standard software platform to improve reliability and reusability as well as to reduce development costs. It is necessary to validate the function and performance of the software from the development stage in order to prevent vehicular accidents. In order to simplify testing of the ECU software and to easily find the cause of an error, AUTOSAR RTE and BSW should be tested prior to integration of the application software. In this study, we propose a test system and test method for the AUTOSAR RTE and BSW. With the proposed AUTOSAR test system, the testing time and effort required during the development could be minimized. The software quality could also be improved by testing the AUTOSAR functions. © 2020 Korean Society of Automotive Engineers. All rights reserved.1

Accurate State Estimation for Electro-Mechanical Brake Systems

Electro-mechanical brake (EMB) system is an electric motor based braking force generation module, and it requires various sensors such as motor position, motor current and clamping force sensor for stable vehicle deceleration control. Because fault in these sensors can lead to degradation of the system performance, system monitoring is essential. To build a model based state estimator for the braking system, there are some requirements: the mathematical model presenting the nonlinearity and disturbance of the real system, fast response time and the accurate estimation. To solve this problem, this paper proposes a new EMB model which clamping force term is divided into the linear and nonlinear compensation part, and Kalman filter algorithm is applied to design the state estimator. The proposed model is simple and linear, and Kalman filter algorithm is robust to system noise and guarantees the fast computation time. Additionally, the braking direction aware and contact point aware clamping force estimation techniques are introduced, and they help to improve the accuracy of the state estimation. Lastly, the proposed approach is verified through experiments on the EMB test bench. © 2019, The Korean Institute of Electrical Engineers.1

An Application on Visual Cognitive Assistance system for Braille Block Recognition Based on Raspberry Pi System

There are many visually impaired people living their lives throughout the world. As of now, the only realistic tools available for these people are white sticks and guide dogs. However, these visual aids are insufficient for handling unexpected obstacles in various environments. Accidents tend to occur frequently, and these aids are very costly, thus limiting their usefulness for the visually impaired. This paper aims to develop a visual aid cognitive system and explores the possibility of practical performance. The overall system configuration uses the Raspberry Pi and OpenCV in real-time to capture braille block images and recognize the braille blocks' pattern. It also gathers information about the surrounding environment before conveying the information to the user.  In the first phase, the Go/Stop signal is determined by the linear or circular braille block according to the type of braille block. In the second phase, the visual aid system equipped with an ultrasonic sensor warns the user when encountering an obstacle so that the user can walk safely. We implemented a text recognition system based on a Text-to-Speech converter that transmits the text recognition information to the visually impaired and tested TTS function to read various street signs with various fonts. We lastly discuss the future possibility for our auxiliary system in various road environments and how it can be improved to help visually impaired people