• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
• /
• pp.436-438
• /
• 2007

As the sensors and communication technology get advance, the remote health diagnosis for patients and senior persons at home are possible now without visiting doctors in hospitals. A low-power ubiquitous health check device was developed adapting Real-Time Embedded Linux is developed. This ubiquitous device is consisted of three sensors. The wrist type health checking terminal acquires periodically the health data by using a blood pressure sensor, a pulse sensor and a body temperature sensor. It transmits the health data to the access point located at the home center through the ZigBee wireless communication modem. This health data collector or access point device sends the data again to the main server operated in a hospital or health care organization. The health server control continuously the input data and sends an alarm signal to the assigned. doctor and responsible persons using cellular SMS when any dangerous events occur. This wrist type health check device has an embedded linux OS using Intel PAX255 MPU. The developed U-Health system is applicable for checking patients health in remote at home. And their family or related persons in remote site can check the patients health status at any time. They can be assured by receiving SMS record and alarm of emergency case which is transmitted from the health server.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
• /
• pp.168-170
• /
• 2006

In this paper, authors realize water AMR(Automatic Meter Reading) network using low power ZigBee protocol included routing ability for improving wireless communitation error detection and network range. ZigBee wireless standard is an important standard of the field related Ubiquitous industry and recently has application to Home-Network. It's special features are to spend low power and to include routing ability each terminator. Because of these features, authors realize water AMR system on Embedded system using ZigBee protocol for applying to transfer data between a water meter and RF module equipped with a water meter in each house.

• Journal of Information Technology Applications and Management
• /
• 제11권1호
• /
• pp.189-200
• /
• 2004

Recently Flash Memory which is small and low-powered is widely used as a storage of embedded system, because an embedded system requests portability and a fast response. To resolve a difference of access time between a storage and RAM, Linux is using disk caching which copies a part of file on disk into RAM. It is not also an exception on embedded system. A READ access-time of flash memory is similar to RAMs. So, when a process on an embedded system reads data, it is similar to the time to access cached data in RAM and to access directly data on a flash memory. On the embedded system using limited memory, using a disk cache is that wastes much time and memory spaces to manage it and can not reflects the characteristic of a flash memory. This paper proposes the regular file access of limited using a page cache in the file system based on a flash memory and reflects the characteristic of a flash memory. The proposed algorithm minimizes power consumption because access numbers of the RAM are reduced and doesn't waste a memory space because it accesses directly to a flash memory Therefore, the performance improvement of the system applying the proposed algorithm is expected.

• 대한임베디드공학회논문지
• /
• 제15권5호
• /
• pp.261-268
• /
• 2020

Genetic algorithms find the optimal solution by mimicking the evolution of natural organisms. In this study, the genetic algorithm was used to enable Pac-Man's reinforcement learning, and a simulator to observe the evolutionary process was implemented. The purpose of this paper is to reinforce the learning of the Pacman AI of the simulator, and utilize genetic algorithm and artificial neural network as the method. In particular, by building a low-power artificial neural network and applying it to a genetic algorithm, it was intended to increase the possibility of implementation in a low-power embedded system.

• 디지털산업정보학회논문지
• /
• 제4권1호
• /
• pp.9-16
• /
• 2008

This paper presents a frequency selection algorithm for minimization power consumption of processor in Mobile System. The proposed algorithm has processor designed low power processor using clock gating method. Clock gating method has improved the power dissipation by control main clock through the bus which is embedded clock block applying the method of clock gating. Proposed method has compared power consumption considered the dynamic power for processor, selected frequency has considered energy gain and energy consumption for designed processor. Or reduced power consumption with decreased processor speed using slack time. This technique has improved the life time of the mobile systems by clock gating method, considered energy and using slack time. As an results, the proposed algorithm reduce average power saving up to 4% comparing to not apply processor in mobile system.

• 한국정보통신학회논문지
• /
• 제11권1호
• /
• pp.66-74
• /
• 2007

일반적으로 사용되고 있는 네비게이션 시스템들은 윈도우 CE 플랫폼에서 동작한다. 리눅스는 무료 운영체제이기 때문에 리눅스 기반 임베디드 단말기들은 가격 경쟁력을 가진다. 하지만 리눅스 기반 임베디드 단말기에 지도시스템을 개발하기 위해서는 풀어야 할 많은 기술적인 장애가 있다. 임베디드 리눅스 단말기는 저출력, 저비용, 낮은 연산 처리 능력을 가진 작은 크기의 플랫폼이기 때문에, 디스크 접근 횟수를 최소화하는 공간 데이터베이스 엔진을 개발하여야 한다. 한글처리, 디버깅 도구의 부재 등의 문제들을 해결하였다. 본 논문에서는 임베디드 리눅스를 사용하는 휴대 단말기에 공간 데이터베이스 엔진과 사용자 인터페이스를 구현하여 위치 기반 지도 시스템을 개발하였다. 구현 결과, 임베디드 리눅스 단말기가 텔레 매틱스 또는 네비게이션 단말기로서 기능을 충분히 수행할 수 있음을 확인하였다.

• 한국정보통신학회논문지
• /
• 제25권7호
• /
• pp.962-970
• /
• 2021

대부분의 자동차 사고는 졸음운전과 같은 운전자의 부주의로 인해 발생한다. 전방 추돌 경보 시스템 (FCWS)은 전방 차량으로부터 추돌 위험을 감지하여 운전자에게 사전에 경고함으로써 사고의 위험을 현저하게 줄여준다. 본 논문은 주행 안전을 위한 저전력 임베디드 기반 FCWS를 소개한다. 단일 카메라로부터 전방 차량에 대해 검출, 추적, 거리를 계산하고 현재 차량의 속도 정보를 통해 충돌시간 (TTC)을 계산한다. 또한 저성능 임베디드 시스템에서 실시간으로 동작하기 위해 높고 낮은 수준의 프로그램 최적화 기법을 소개한다. 이 시스템은 임베디드 시스템에서 사전에 취득해둔 주행 영상을 통해서 테스트 하였다. 최적화 기법을 사용한 결과는 이전에 최적화를 하지 않은 프로세스 보다 실행 시간이 약 170배 향상되었다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
• /
• 제11권6호
• /
• pp.477-487
• /
• 2005

내장형 컴퓨터의 규모가 커지고 기능이 복잡해짐에 따라 동적 메모리 할당 기법은 전체 시스템의 성능을 좌우하는 중요한 요인으로 등장하였다. 본 논문의 목적은 내장형 시스템에서 동적 메모리 할당 기법을 사용할 때 하드웨어, 소프트웨어 구성에 따른 성능을 측정하는데 있다. 기존의 연구가 운영체제를 탑재하지 않은 단일 스레드의 단일 메모리 주소 공간을 갖는 시스템을 대상으로 한 반면 본 논문은 실제 환경과 같이 리눅스 운영체제를 탑재한 내장형 시스템을 사용한다 이러한 시스템 기반에서 소프트웨어의 각 계층과 하드웨어 설계 인자의 변화에 따른 동적 메모리 할당의 수행시간을 실험적으로 분석하였다. 본 논문의 정량적인 성능분석 결과는 시스템 설계자에게 유용한 데이터를 제공함으로써 보다 효율적인 고성능 저전력 내장형 시스템의 구현을 가능하게 할 것이다.

• 유공압시스템학회논문집
• /
• 제4권1호
• /
• pp.18-24
• /
• 2007

The continuously variable transmission (CVT) of which speed ratio can change continuously in a fixed range has the benefits of low fuel consumption and exhaust gas because it enables the engine of a vehicle to operate in a high efficiency range regardless of vehicle speed. The speed ratio of belt type CVT is controlled by adjusting line pressure. The one of the line pressure control methods, mechanical-hydraulic control is usually adopting VDT's control method, in which the secondary solenoid valve has two functions both a regulator and a line pressure controller. However, this control method could not show the high performance of CVT with optimal driving capability because of the limitation of simple control algorithm, and it could not gain market share sufficiently in spite of the advantage of CVT with low fuel consumption. On the other hand, the electro-hydraulic control method gives the enhancement of power performance and low fuel consumption by implementing various driving mode using the proportional control or PWM control. The key of CVT technique is to develop a control algorithm of the electro-hydraulic solenoid valve in order to implement the speed ratio efficiently. In this paper, the line pressure control algorithm is proposed and the hydraulic system is controlled using metal belt type CVT test rig and the embedded ECU platform.

• ETRI Journal
• /
• 제29권3호
• /
• pp.259-269
• /
• 2007

The ubiquitous flexible operating system (UbiFOS) is a real-time operating system designed for cost-conscious, low-power, small to medium-sized embedded systems such as cellular phones, MP3 players, and wearable computers. It offers efficient real-time operating system services like multi-task scheduling, memory management, inter-task communication and synchronization, and timers while keeping the kernel size to just a few to tens of kilobytes. For flexibility, UbiFOS uses various task scheduling policies such as cyclic time-slice (round-robin), priority-based preemption with round-robin, priority-based preemptive, and bitmap. When there are less than 64 tasks, bitmap scheduling is the best policy. The scheduling overhead is under 9 ${\mu}s$ on the ARM926EJ processor. UbiFOS also provides the flexibility for user to select from several inter-task communication techniques according to their applications. We ported UbiFOS on the ARM9-based DVD player (20 kB), the Calm16-based MP3 player (under 7 kB), and the ATmega128-based ubiquitous sensor node (under 6 kB). Also, we adopted the dynamic power management (DPM) scheme. Comparative experimental results show that UbiFOS could save energy up to 30% using DPM.