• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2193-2196
• /
• 2003

기존의 멀티레이트 입력 (MRIC) 제어기는 제어 입력신호에 채터링 현상이 발생하여 추종응답에 리플이 발생하는 문제점이 있다. 이러한 리플현상을 해결하기 위해 피드포워드 보상기를 이용하여 이런 리플현상을 제거하는 방법이 제시되기도 하였다. 본 논문에서는 상태 공간에서 현재 추종기를 기반으로 리프팅 기법을 이용한 멀티레이트 입력제어기 설계를 소개한다. 본 제어기를 사용함으로써 제어입력 신호가 채터링이 생기지않음을 이산전달함수 관점에서 최종치 정리를 이용하여 증명한다.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.4 no.5
• /
• pp.462-473
• /
• 1999

This paper addresses the current measurement issue of all digital field oriented control of ac motors. The p paper focuses on the effect of low-pass filter and also on the sampling of the fundamental component of the m motor current. The low-pass filter, which suppresses the switching noise of the motor current, introduces v variable phase delay according to the current ripple frequency. It is shown that the current sampling error c consists of the fundamental component and high frL'quency ripple components. In this paper, the dependency of t this current sampling e$\pi$or on the reference voltage vector is investigated analytically and a sampling technique i is proposed to minimize the error. The work is based on the three phase symmetry pulse width modulation l inverter driving an induction machine. With this technique, the bandwidth of current regulator can be extended t to the limit given by the switching frequency of the inverter and more precise torque regulation is possible.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.44 no.10
• /
• pp.99-109
• /
• 2007

IEEE 802.lie is being proposed to improve QoS by IEEE 802.11 working group. HCCA (HCF Controlled Channel Access) a centralized polling based mechanism of IEEE 802.11e, needs a scheduling algorithm that decides on how the available radio resources are allocated to the polled STAs. In IEEE 802.l1e standard Reference Scheduler is presented. Reference Scheduler Polls all STAs in a polling list by the same interval that causes ineffectively frequent polling. It increases not only the overhead but it decreases the TXOP (Transmission Opportunity) utilization. In this paper, we propose the scheduling and admission control algorithm that poll stations depending on the MSI (Maximum Service Interval)o( stations to solve these shortcomings. In our proposed algorithm a station is polled by an interval close to its MSI, so polling overhead decrease and TXOP utilization increases than Reference Scheduler. Simulation results show that our algorithm outperforms Reference Scheduler. Our algorithm maintains higher aggregate throughput and services mere stations than Reference Scheduler.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.8
• /
• pp.157-161
• /
• 2010

Most of air pollution in a metropolis is the result of exhaust gas emissions from automotive vehicles, and the world-wide regulation against environmental pollution is becoming more strict. Moreover the demand on development and supply of an environment-friendly automobile is increasing and the market share about that is expected to grow rapidly in this time of high oil price. The secondary batteries the most important component to store the electrical energy in hybrid electric vehicle. It needs to the higher power characteristics to emit the energy instantaneous. In this paper, we proposed the system to monitor reliably the charge and discharge states of the secondary batteries for hybrid electric vehicle. The material is about SW and HW module the software and hardware module mounted on the charge and discharge system and the monitoring system to control the charge and discharge performance effectively.

• Journal of KIISE:Computer Systems and Theory
• /
• v.30 no.1
• /
• pp.22-32
• /
• 2003

Many of multimedia applications in distributed environments generate the packets which have the real-time characteristics for continuous audio/video data and transmit them according to the teal-time task scheduling theories. In this paper, we model the traffic for continuous media in the distributed multimedia applications based on the high-bandwidth networks and introduce the PDMA algorithm which is the hard real-time task scheduling theory for guaranteeing QoS requested by the clients. Furthermore, we propose the admission control to control the new request not to interfere the current services for maintaining the high quality of services of the applications. Since the proposed admission control is sufficient for the PDMA algorithm, the PDMA algorithm is always able to find the feasible schedule for the set of messages which satisfies it. Therefore, if the set of messages including the new request to generate the new traffic. Otherwise, it rejects the new request. In final, we present the simulation results for showing that the scheduling with the proposed admission control is of practical use.

• Journal of IKEEE
• /
• v.22 no.3
• /
• pp.645-650
• /
• 2018

IT-based automatic controller that control the temperature and humidity to prevent dew condensation of distributing board was designed and implemented in this paper. The dew condensation temperature was deduced from room temperature and humidity of distributing board. Based on the comparisons between the deduced dew condensation temperature and the temperature of surface condensation, the facilities that can prevent the condensation was implemented to be operated in due order. Also, the remote monitoring module to monitor operation status of controller was implemented using LoRa technique. The performances for controller operation and data transmission were validated from the transmission and operation test for dew condensation prevention. The controller can be put to good use at the facilities that requires the condensation prevention.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.37 no.3
• /
• pp.33-43
• /
• 2000

The guarantee of the fast dynamics stability is essential for successful application of singular Perturbation technique to control systems design. Even though the fast dynamics of the control systems is rendered stable by an analog controller, the fast dynamics stability of the control systems resulted from an digital implementation of the analog controller can be impaired severely. In this paper, we first investigate the time sampling effects on singular perturbation based control systems by centering on a design example of recently developed singular perturbation based STT missile autopilot with high performance. The investigation shows that the stability margin the fast dynamics of the STT misile autopilot system decreases rapidly as the sampling interval of discretizing the analog autopilot increases. Under this analysis, we propose a composite digital controller with compensation for the decreasing stability margin of the fast dynamics due to time sampling to achieve better performance with respect to sampling time. The improved performance of the proposed composite digital controller is verified by simulation. This result shows that one needs to investigate time sampling effects in the digital implementation of singular perturbation based controllder, and then can have benefit from the investigation.

• KIPS Transactions on Computer and Communication Systems
• /
• v.8 no.12
• /
• pp.297-304
• /
• 2019

The technological advances such as communication, sensor, and artificial intelligence lead smart factory construction. Smart factory aims at efficient process control by utilizing data from the existing automation process and intelligence technology such as machine learning. As a result of constructing smart factory, productivity increases, but costs increase. Therefore, small companies try to make a step-by-step transition from existing process to smart factory. In this paper, we have proposed a remote control system that support data collection, monitoring, and control for manufacturing equipment to support the construction of CNC cutting machine based small-scale smart factory. We have proposed the structure and design of the proposed system and efficient sensing data transmission scheme. To check the feasibility, the system was implemented for CNC cutting machine and functionality verification was performed. For performance evaluation, the web page access time was measured. The results means that the implemented system is available level.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.12
• /
• pp.25-32
• /
• 2009

This paper proposes the construction of intelligent home network system using Power Line Communication(PLC) technique, which allows for UPnP bridge remote control and monitoring based on TCP/IP. Also, the communication for control module inside intelligent home network systems is designed with Simple Control Protocol (SCP) in which each device is connected to be controlled independently. When new UPnP device is additionally installed in intelligent home network systems, it is monitored through UPnP bridges based on its registered UPnP device information. The device control based on PLC and implementation of each UPnP device are effectively managed by using TCP/IP remote control and it's provided fundamental functions to monitor various device information in the home network.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2016.07a
• /
• pp.105-106
• /
• 2016

본 논문에서는 방범용 CCTV 시스템의 빈번한 장애를 처리하는데 원격지 방문으로 소요되는 시간과 인력의 소모를 개선하기 위해 모니터링 및 단순장애 자가 처리 기능을 탑재한 방범용 CCTV를 위한 지능형 모니터링 시스템을 제안한다. 지능형 모니터링 시스템은 센서 모듈에서 측정된 값을 지능형 모니터링 모듈에서 취합하고 모니터링 하여 자가 처리 여부를 판단하고, 이에 따라 제어모듈과 통신하거나 상황실에 알림 등의 여부를 판단하여, 네트워크를 통해 원격으로 방범용 CCTV의 상태를 모니터링하고 장애발생을 예측하여 자가 처리 하거나 원격 처리할 수 있다.