• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.205-214
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• 2008

To transfer large amount of packets fast in sensor network, it is necessary that the delay between successive packet transmissions should be minimized as possible. In Sensor network, since the Operating Systems are worked on the event driven, the Timer Event is used to transfer packets successively. However, since the transferring time of packet completely is varies very much, it is very hard to set appropriate interval. If interval is too long, delay also becomes too long but if interval is too short, the fail of transfer request would increase. In this paper, we propose ESTEO which reduces the delay between successive packet transmissions by using SendDone Event which informs that a packet transmission has been completed. In ESTEO, the delay between successive packet transmissions is shortened very much since the transmission of next Packet starts at the time when the transmission of previous packet has completed, irrespective of the transmission time. Therefore ESTEO could provide high packet transmission rate given large amount of packets.

• Journal of Industrial Technology
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• v.27 no.B
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• pp.235-243
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• 2007

Sensor network is used to obtain sensing data in various area. The interval to sense the events depends on the type of target application and the amounts of data generated by sensor nodes are not constant. Many applications exploit long sensing interval to enhance the life time of network but there are specific applications that requires very short interval to obtain fine-grained, high-precision sensing data. If the number of nodes in the network is increased and the interval to sense data is shortened, the amounts of generated data are greatly increased and this leads to increased amount of packets to transfer to the network. To transfer large amount of packets fast, it is necessary that the delay between successive packet transmissions should be minimized as possible. In Sensor network, since the Operating Systems are worked on the event driven, the Timer Event is used to transfer packets successively. However, since the transferring time of packet completely is varies very much, it is very hard to set appropriate interval. The longer the interval, the higher the delay and the shorter the delay, the larger the fail of transfer request. In this paper, we propose ESTEO which reduces the delay between successive packet transmissions by using SendDone Event which informs that a packet transmission has been completed.In ESTEO, the delay between successive packet transmissions is shortened very much since the transmission of next packet starts at the time when the transmission of previous packet has completed, irrespective of the transmission timee. Therefore ESTEO could provide high packet transmission rate given large amount of packets.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1123-1140
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• 2019

Many Internet of Things (IoT) applications involving bursty traffic have emerged recently with event detection. A power management scheme qualified for uplink bursty traffic (PM-UBT) is proposed by distinguishing between bursty and general uplink traffic patterns in the IEEE 802.11 standard to balance energy consumption and uplink latency, especially for stations with limited power and constrained buffer size. The proposed PM-UBT allows a station to transmit an uplink bursty frame immediately regardless of the state. Only when the sleep timer expires can the station send uplink general traffic and receive all downlink frames from the access point. The optimization problem (OP) for PM-UBT is power consumption minimization under a constrained buffer size at the station. This OP can be solved effectively by the bisection method, which demonstrates a performance similar to that of exhaustive search but with less computational complexity. Simulation results show that when the frame arrival rate in a station is between 5 and 100 frame/second, PM-UBT can save approximately 5 mW to 30 mW of power compared with an existing power management scheme. Therefore, the proposed power management strategy can be used efficiently for delay-intolerant uplink traffic in event-driven IoT applications, such as health status monitoring and environmental surveillance.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.89-96
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• 2020

Solar lamp systems may not operate normally in the event of some system or controller failure due to internal or external factors, in which case secondary problems occur, which may cost the system recovery. Thus, when these errors occur, a technology is needed to recover to the state it was in before the failure occurred and to enable re-execution. This paper designs and implements a system that can recover the state of the system to the state prior to the time of the error by using the Watchdog Timer within the controller if a software error has occurred inside the system, and it also proposes a technology to reset and re-execution the system through a separate reset circuit in the event of hardware failure. The proposed system provides stable operation, maintenance cost reduction and reliability of the solar lamp system by enabling the system to operate semi-permanently without external support by utilizing the automatic recovery and automatic reset function for errors that occur in the operation of the solar lamp system. In addition, it can be applied to maintain the system's constancy by utilizing the self-operation, diagnosis and recovery functions required in various high reliability applications.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.6
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• pp.18-26
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• 2011

Debates concerning the competitive edge of leading 3DTV technology of the shutter glasses (SG) 3D and the film-type patterned retarder (FPR) are flaring up. Although SG technology enables Full-HD 3D vision, it requires complex systems including the sync transmitter (emitter), the sync processor chip, and the LCD lens in the active shutter glasses. In addition, the transferred sync-signal is easily affected by the external noise and a 3DTV viewer may feel flicker-effect caused by cross-talk of the left and right image. The operating current of the sync processor in the 3DTV active shutter glasses is gradually increasing to compensate the sync reconstruction error. The proposed chip is a low-power hardware sync processor based discrete-event SoC(system on a chip) designed specifically for the 3DTV active shutter glasses. This processor implements the newly designed power-saving techniques targeted for low-power operation in a noisy environment between 3DTV and the active shutter glasses. This design includes a hardware pre-processor based on a universal edge tracer and provides a perfect sync reconstruction based on a floating-point timer to advance the prior commercial 3DTV shutter glasses in terms of their power consumption. These two techniques enable an accurate sync reconstruction in the slow clock frequency of the synchronization timer and reduce the power consumption to less than about a maximum of 20% compared with other major commercial processors. This article describes the system's architecture and the details of the proposed techniques, also identifying the key concepts and functions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2786-2791
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• 2014

This paper describes the smart illuminating system based on the obstacle environmental presetting to improve the user convenience to easy lighting and energy conservation. Obstacle environment has trouble controlling the illuminating equipment using manual buttons in certain circumstances, which requires a smart remote controller. The smart remote controller is operated by the smart phone, motion sensor and timer to turn on and off the lamps. The event sensor module transmits the signals of the event occurrence to equipment on the remote place when smart phone and motion sensor detect an event, and the illuminator received the event turn on or off the lamp. The system results in energy saving by simple on/off control and manipulating the operating time with controlling the illuminating system preset by user's obstacle or preference circumstances. The proposed system implementation is experimented to figure out the energy saving about13.5w/h and the optimized convenience control.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.901-907
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• 1998

This paper presents a real-time control technique for the development of a ship main engine remote control system, In general several tasks are executed by the event-driven method in real-time system. However when some tasks have time delay components it is difficult to achieve good real-time performance. To cope with this problem a number of timers in most conventional system have been used. In this paper we introduce a real-time control methodology of dealing effectively with tasks including time delay components using one hardware timer. And also a speed control method of main engine which includes critical revolution range a crash astern and a emergency ahead function a switching method of remote control position and a flickering method for the indication of multi-stage alarm are discussed. As long as functions and method are imple-mented as forms of tasks the development of main engine remote control systems can be easy for different types of engines.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.2
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• pp.101-105
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• 2006

The Engineering Model of STSAT-2 on-board computer(OBC) was developed and tested completely with other sub-systems. The on-board computer of STSAT-2 has a high- performance PowerPC processors and a structure of centralized network communication. In addition, a lot of logics are implemented by Field Programmable Gate Array, such as interrupt controller, watchdog timer and UART. It could make the weight and size of OBC lighter and smaller. Also, the STSAT-2 on-board computer has more improved tolerance against Single Event Upsets and faults than that of the STSAT-1.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.307-309
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• 2002

본 논문에서는 가입관망의 광대역화 및 고속화를 실현는 방안으로 개발되고 있는 광대역 무선접속시스템 가입자국의 MAC 프로토콜을 설계하고 구현하였다. MAC 프로토콜은 제한된 무선자원을 효율적으로 사용하기 위한 프로토콜로서, 무선매체를 이용하여 통신서비스를 제공하는 시스템에 필수적이다. 본 논문에서 설계한 가입자국 MAC 프로토콜은 실시간처리부, 타이밍관련처리부, 상향스트림제어처리부, 그리고 하향스트림처리부를 하드웨어로 설계하고, 이를 제어하고 MAC 제어메시지 동작절차를 수행하는 부분과 망접속부를 소프트웨어를 설계하였다. MAC 소프트웨어는 MAC 응용부, Timer 처리부, Event 처리부, Network 인터페이스부로 나누어 설계하였으며, 본 논문에서 설계된 가입자국 MAC 프로토콜은 향후, 광대역무선접속시스템의 실제 테스트베드에 이식하여 시스템의 전체적인 성능을 검증할 수 있다.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.4
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• pp.193-199
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• 2012

Virtualization allows multiple commodity operating systems to share on a single physical machine. Resource allocation among virtual machines is a key to determine virtual machine performance. To satisfy time-sensitive task on a domain, hypervisor needs to observe the resource requirements and allocates proper amount of CPU resources in a timely manner. In this paper, we propose a realtime credit scheduler for latency sensitive application on virtual machines. The key idea is to register a time event in the Xen hypervisor. Experiment result shows that the proposed scheme is superior to Credit scheduler.