Choon-Woo Lee

Supercritical Fluid Deposition of Conformal SrTiO3 Films with Composition Uniformity in Nanocontact Holes

SrTiO 3 with a high dielectric constant is considered a promising capacitor dielectric for dynamic random access memory. Until now, a SrTiO 3 deposition with compositional uniformity and perfect conformality inside high-aspect nanoscale holes has been difficult by chemical vapor deposition (CVD) and atomic layer deposition (ALD). In this study, we report a supercritical fluid deposition (SCFD) of SrTiO 3 . Compared to CVD SrTiO 3 , the SCFD SrTiO 3 showed perfect conformality and compositional uniformity inside nanosize holes. From these results, the SCFD is expected to be a solution for the stoichiometry and conformality issues of the CVD and ALD SrTiO 3 .

Performance Improvement of a Pedestrian Dead Reckoning System using a Low Cost IMU

This paper proposes a method for PDR (Pedestrian Dead-Reckoning) using a low cost IMU. Generally, GPS has been widely used for localization of pedestrians. However, GPS is disabled in the indoor environment such as in buildings. To solve this problem, this research suggests the PDR scheme with an IMU attached to the pedestrian`s waist. However, despite the fact many methods have been proposed to estimate the pedestrian`s position, but their results are not sufficient. One of the most important factors to improve performance is, a new calibration method that has been proposed to obtain the reliable sensor data. In addition to this calibration, the PDR method is also proposed to detect steps, where estimation schemes of step length, attitude, and heading angles are developed. Peak and zero crossings are detected to count the steps from 3-axis acceleration values. For the estimation of step length, a nonlinear step model is adopted to take advantage of using one parameter. Complementary filter and zero angular velocity are utilized to estimate the attitude of the IMU module and to minimize the heading angle drift. To verify the effectiveness of this scheme, a real-time system is implemented and demonstrated. Experimental results show an accuracy of below 1% and below 3% in distance and position errors, respectively, which can be achievable using a high cost IMU.

Design and Implementation of Pedestrian Position Information System in GPS-disabled Area

Abstract In this paper, we propose a Pedestrian Position Information System(PPIS) using low-cost inertial sensors in GPS-disabled area. The proposed scheme estimates the attitude/heading angle and step detection of pedestrian. Additionally, the estimation error due to the inertial sensors is mitigated by using additional sensors. We implement a portable hardware module to evaluate performance of the proposed system. Through the experiments in indoor building, the estimation error of position information was measured as 2.4% approximately. Key Words : IMU, GPS, Position information, sensor fusion, Kalman filter 본 논문은 삼성탈레스 연구과제로 수행되었음. * Corresponding Author : Sang-Hoon Park Tel: +82-31-601-5184 email: sh75.park@samsung.com 접수일 12년 06월 28일 수정일 12년 07월 25일 게재확정일 12년 09월 06일 1. 서론 위치정보는 이동체에 대한 중요한 정보 중 하나이다. 따라서 이동체에 대한 위치정보를 인식 또는 추정하는 기술은 정보시스템에서 핵심기술로서 인식되고 있으며 적용분야 또한 매우 광범위하다. 기존에 위치정보시스템이 적용되어온 분야는 주로 항공기 및 자동차와 같은 분야이다. 최근에는 보행자의 위치를 인식하는 기술의 중요성이 대두되고 있으며 연구가 활발히 진행되어지고 있다. 보행자 위치인식시스템은 소방, 경찰, 보병(군) 등 활용분야가 무궁무진한 분야이다. 예를 들어 경찰용으로는 미아 및 분실물 찾기, 범죄자 및 특정인의 위치추적 등에 활용되어질 수 있다.GPS(Global Positioning System)는 기존에 이동체의 위치인식 분야에서 가장 널리 사용된 기술로서, 보행자용 위치인식시스템에도 적용될 수 있다. 기본적으로 GPS는 위성을 이용하여 이동체의 절대적인 위치를 제공한다. 그러나 보행자가 건물내부와 같은 위성신호 수신이 불가한 지역으로 진입 시 위치인식이 단절되는 단점이 있다. 최근에는 상기한 GPS 방식의 단점을 해결하기 위해 WLAN(Wireless Local Area Network), UWB(Ultra WideBand), CSS(Chirp Spread Spectrum) 등과 같은 무선통신 기술을 활용한 통신항법 기반의 실내 위치인식 기술이 활발히 연구되고 있다[1-3]. 이러한 통신항법을 이용한 위치인식기술은 무선통신을 위한 인프라가(예: access point) 기존에 구축되어 있어야 한다. 따라서 인프

Assessment of Sustainable Production on Paddy Field Treated with Green Manure Crops Using Sustainability Index

Assessment of sustainable production on a cropland can help to determine the most proper management practices. In this study, we evaluated the sustainable production on paddy field treated with green manure crops using sustainability index which based on nutrient index, microbiological index, and crop index related to nutrient-supplying capacity. Especially choosing appropriate indicators from a minimum data set (MDS) were used the principal components analysis (SI-2) as well as expert opinion (SI-1) usually used in sustainability index. Six treatments including the two tillage treatments and two green manure crops were investigated as follows; (i) moldrotary + rotary tillage without green manure crop (Con), with (ii) hairy vetch (Con-HV), and (iii) hairy vetch + green barely (Con-HV+GB), (iv) rotary tillage without green manure crop (Rot), with (ii) hairy vetch (Rot-HV), and (iii) hairy vetch + green barly (Rot-HV+GB). Con-HV and Rot-HV in SI-1 were maintained sustainability while Rot-HV and Rot-HV+GB in SI-2. Especially, treatments (Con and Rot) without green manure crops were more unsustainable than with green manure crops because of the low value of microbiological and crop index than with green manure crops. Meanwhile, sustainability indices and grain yield had the high correlation values (R²=0.756 and 0.928 in SI-1 and SI-2, respectively). These results meant that application of green manure crops such as hairy vetch could improve both yield and soil quality in paddy.

Design and Implementation of Biosignal Monitoring for Enhancement of Soldier Survivability

Recently, personal health monitoring system using intelligent biosensors and equipments has been realized. This system can be adopted for soldier`s biosignal monitoring system. In this paper, we propose a soldier biosignal monitoring system using personal biosensors, such as the ECG sensors and accelerometer.