• Journal of IKEEE
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• v.23 no.3
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• pp.1068-1076
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• 2019

Most of the electronics we use today have built-in microcontrollers, which are called embedded systems. In such a small environment, responsiveness is very important for the microcontroller. In this paper, the basic input/output control, timer/counter interrupt operation principle, and understanding of the microcontroller are described. Program logic is proposed to improve throughput and latency by controlling characteristics of service routine and program execution order. The hardware simulations in this paper were verified using ATmega128 and PIC16F877A from Atmel and Microchip.

• Journal of Software Assessment and Valuation
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• v.16 no.1
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• pp.89-94
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• 2020

In this paper, we propose a software algorithm that can configure n-key roll-over that detects all keys without limitation on the number of pressed keys in the dynamic scanning detection of a keyboard composed of a matrix. The proposed algorithm uses the timer interrupt of the microcontroller for computer keyboard control, so that a constant and accurate detection interval can be obtained, and an accurate debounce time can be provided. In order to confirm the effectiveness of the proposed algorithm, a microcontroller was connected to a toy keyboard constructed in the form of a clavier and experiments were conducted. As a result of the experiment, it was confirmed that detection of all keys was performed accurately regardless of the number of keys pressed.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.11
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• pp.626-634
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• 2004

In a client-server model, network server systems suffer from both heavy communication and computational loads. While communication channels become increasingly speedy, the existing protocol stack architectures still include mainly three performance bottlenecks of protocol stack processing, system call, and network interrupt overheads. To address these obstacles, in this paper we present a host-independent network system where a network interface card (NIC) is utilized in an efficient manner. First, by offloading network-related portion to the NIC, the host can fully utilize its processing power for other useful purposes. Second, it eliminates the system call overhead, such as context-switching and memory copy operations, since the host communicates with the NIC through its user-level libraries. Third, it a] so reduces the network interrupt operation count as the host handles the interrupt in a segment instead of a packet. The experimental results show that the proposed network system reduces the host CPU overhead for communication system by 68-71%. It also shows that the proposed system improves the communication speed by 11-83% under heavy computational and communication load conditions.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.10a
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• pp.80-80
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• 2011

본 논문은 윈도우에 디바이스 드라이버 형태로 동작하는 실시간 이식 커널을 제안한다. x86하드웨어에서 제공하는 Local APIC(Advanced Programmable Interrupt Controller)를 이용하여 윈도우와는 별도의 타이머를 제공하여, 독립적인 타이머 인터럽트를 통해 실시간성이 필요한 서비스가 정확한 주기로 동작하여 마감시한을 보장한다. 그리고 1553b 통신에서 IP470을 통해 오실로 스코프로 테스트하여 제안한 실시간 이식 커널이 실시간성을 보장함을 보인다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.340-342
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• 2003

범용 컴퓨터가 아닌 홈 네트워크로 연결된 정보가전용 실시간 시스템에 내장되는 운영체제인 정보가전용 실시간 운영체제는 디지털 TV, 웹 TV, WebPad, PDA, Smart Phone 등에 사용된다. 그러나 정보가전용 실시간 운영체제는 선점형 스케줄링, 멀티 태스킹 및 태스크간 예측 가능한 동기화 방법 그리고 짧고 제한된 인터럽트 처리와 작은 실행 이미지 등과 같은 특징들을 갖는다. 본 논문에서는 이와 같은 특징들을 만족하는 정보가전용 실시간 운영체제를 DVD 플레이어에 적용하여 설계 및 구현한 내용을 기술한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.5-6
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• 2019

보통 MCU를 기반으로 하는 임베디드 소프트웨어는 펌웨어 형태로 구현되어 콘솔이 없고, UART는 데이터 송신용으로 사용된다. 그러나 MCU 소프트웨어에 콘솔 드라이버를 구현하면 유닉스·리눅스와 같은 대화적 표준 입·출력 개발환경과 타스크 개념을 실현할 수 있다. 이 논문에서는 운영체제 교과에서 익힌 내용을 바탕으로 Atmega2560 MCU에 인터럽트 기반 콘솔 장치 구동기를 구현하고 실험한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.367-368
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• 2010

온라인 기반의 교육 시스템이 다양한 시행착오를 거쳐 많은 발전을 이루고 있다. 기존의 오프라인 교육 시스템의 교육 효과를 높이기 위한 온라인 교육 시스템은 그 보조적 수단에서 독자적인 교육 시스템으로의 발전 양상을 보이고 있다. 본 논문에서는 교육 시스템 개발자와 사용자 간의 상호작용 유형 가운데 문의형 상호작용을 기반으로 자가 조절 학습 효과를 높였던 이전 연구에서 발생 할 수 있는 사용자 부담률을 낮추기 위해 전문가 인터럽트 방식을 도입하여 개선된 자가 조절 문의형 교육 시스템을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.45-46
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• 2009

최근에 다기능 복합화되는 임베디드 시스템을 위한 가상화 연구가 활발하다. 본 논문에서는 L4 마이크로커널을 기반으로 한 실시간 운영체제 MicroC/OS-II 가상화를 위한 L4 환경에서의 전체 구성, 인터럽트 핸들링, 게스트 운영체제 초기화 과정의 설계에 대해 기술한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.207-215
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• 2014

In this paper, we propose a Micro Real-Time Control System (MRTCS) for decreasing the delay during interrupts processing and data transfer on sensor nodes. The MRTCS consists of a control, sensor nodes based on Controller Area Network (CAN) device. The control node was designed with Real Time Operating System (RTOS) on top of the small Micro Control Unit (sMCU). Sensor nodes have the CAN device without sMCU, which have multiple Digital Inputs, Outputs (DI/DO) and the CAN controller. We have evaluated with OCTAVE v3.6.4 from open source for system performance. Simulation results show that the system performance was increased through the delay reducing for interrupt processing and internal data transfer. We verify that a proposed MRTCS approach will be adapted to various real-time control system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1251-1258
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• 2002

The weather FAX machine is the one of necessary of safety navigation for ship. which is the machine which make the weather image by the receiving radio signal which is modulated using FSK method and transmitted on air by coast station. after Coast station scan the weather image and broadcast the image with black dot to 1500Hz and white dot to 2300Hz using FSK modulation. This paper implement weather fax machine using only general IBM-PC by software. By using IBM-PC we can make some good functions like print, edit, save etc. The modulated signal from SSB go into RS232C port via photo coupler not to give damage to PC. by using Timer Interrupt and RS232C serial interrupt, we can measure signal frequency and remake weather image. This paper use only IBM-PC with general SSB receiver which is widely spread on the ship. so this is very economic and possible to implement mutifunctions.