• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 ITC-CSCC -1
• /
• pp.77-79
• /
• 2000

Industrial communication networks have attracted much attention in the area of decentralized control systems for factory automation and computer integrated manufacturing. In this paper, we investigate the rate-based traffic control of industrial communication networks employing LonWorks to improve the performance measures of throughput, fairness, and error rates. To this end, we utilize the Feedback channel information through the additional network monitoring node and make the overall system closed-loop. We demonstrate the improved performance of the controlled network system by the experimentation upon an implemented lab-scale network system.

• IEIE Transactions on Smart Processing and Computing
• /
• 제5권2호
• /
• pp.71-76
• /
• 2016

A controller area network (CAN) receiver measures differential voltage on a bus to determine the bus level. Since 3.3V transceivers generate the same differential voltage as 5V transceivers (usually ${\geq}1.5V$), all transceivers on the bus (regardless of supply voltage) can decipher the message. In fact, the other transceivers cannot even determine or show that there is anything different about the differential voltage levels. A new CMOS RC oscillator insensitive supply voltage for clock generation in a CAN transceiver was fabricated and tested to compensate for this drawback in CAN communication. The system consists of a symmetrical circuit for voltage and current switches, two capacitors, two comparators, and an RS flip-flop. The operational principle is similar to a bistable multivibrator but the oscillation frequency can also be controlled via a bias current and reference voltage. The chip test experimental results show that oscillation frequency and power dissipation are 500 kHz and 5.48 mW, respectively at a supply voltage of 3.3 V. The chip, chip area is $0.021mm^2$, is fabricated with $0.18{\mu}m$ CMOS technology from SK hynix.

• 한국정보전자통신기술학회논문지
• /
• 제14권6호
• /
• pp.461-466
• /
• 2021

드론의 제어는 가까운 거리의 경우 블루투스 통신과 같은 방법으로 제어가 가능하고, 원거리는 네트워크 통신을 통해서 제어가 가능하다. 특히 활동범위가 원거리인 경우는 GPS를 이용하여 좌표를 설정하고 네트워크 통신과 영상통신을 이용하여 드론을 제어하게 된다. 그러나 네트워크 통신이나 영상통신에 문제가 발생하여 드론이 제어권한 영역 밖으로 이탈했을 경우, 이를 적절하게 대응하여 제어권한을 강제로 받아서 드론을 조종하여야 한다. 따라서 본 연구에서는 이를 위하여 상호 약속된 단순 동작으로 드론을 제어하는 방법을 제안하고, 드론이 제어권한 밖으로 이탈 했을 경우에도 제안한 방법으로 드론을 제어할 수 있도록 하고자 한다. 이를 구현하기 위하여 제안한 상호 약속된 단순 동작 알고리즘은 기준자세를 설정하고, 드론이 이를 인식했을 경우 자동으로 드론의 제어권한을 기준자세를 취하는 사람에게도 넘어가게 하였다. 그리고 모든 명령의 시작은 기준자세(드론의 호버링 자세)로부터 출발하여 드론의 모든 동작을 제어할 수 있도록 하였다. 마지막으로 드론의 제어권한은 목적 달성 이후 반드시 돌려주고, 드론 스스로 다음 동작을 할 수 있도록 알고리즘을 구현하였고, 맵핑된 명령에 의해 드론이 정상적으로 동작함을 확인할 수 있었다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
• /
• pp.90.2-90.2
• /
• 2013

Vertically-aligned silicon nanostructure arrays (SNAs) have been drawing much attention due to their useful electrical properties, large surface area, and quantum confinement effect. SNAs are typically fabricated by chemical vapor deposition, reactive ion etching, or wet chemical etching. Recently, metal-assisted chemical etching process, which is relatively simple and cost-effective, in combination with nanosphere lithography was recently demonstrated for vertical SNA fabrication with controlled SNA diameters, lengths, and densities. However, this method exhibits limitations in terms of large-area preparation of unperiodic nanostructures and SNA geometry tuning independent of inter-structure separation. In this work, we introduced the layerby- layer deposition of polyelectrolytes for holding uniformly dispersed polystyrene beads as mask and demonstrated the fabrication of well-dispersed vertical SNAs with controlled geometric parameters on large substrates. Additionally, we present a new means of building in vitro neuronal networks using vertical nanowire arrays. Primary culture of rat hippocampal neurons were deposited on the bare and conducting polymer-coated SNAs and maintained for several weeks while their viability remains for several weeks. Combined with the recently-developed transfection method via nanowire internalization, the patterned vertical nanostructures will contribute to understanding how synaptic connectivity and site-specific perturbation will affect global neuronal network function in an extant in vitro neuronal circuit.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 2003년도 춘계학술대회논문집
• /
• pp.61-66
• /
• 2003

Mobile IP has been designed only to maintain communication as they move form place to place, so it doesn't guarantee Quality of Service(QoS). QoS in mobile IP is important to provide multimedia and real-time applications services in mobile, and it is closely related to handoff delay. Therefore, handoff delay problem is actively studied to guarantee QoS as a main issue in mobile IP research area Next generation Mobile IPv6 resolve this problem somewhat, triangle problem for first packet and handoff delay still remain. In this paper, we suggest SNMP Information-based routing that adds keyword management method to Information-based routing in active network in order to resolve such a problem, and then suggest QoS controlled handoff based on SNMP Information-Based routing. After modeling of suggested method and existing handoff method simulations we carried out with NS-2 for performance evaluation. The results of simulations show the some improvement on handoff delay, and therefore on QoS improvement.

• Journal of Astronomy and Space Sciences
• /
• 제31권3호
• /
• pp.235-240
• /
• 2014

The communications link in a space program is a crucial point for upgrading its performance by handling data between spacecraft bus and payloads, because spacecraft's missions are related to the data handling mechanism using communications ports such as a controlled area network bus (CAN Bus) and a universal asynchronous receiver and transmitter (UART). The NEXTSat-1 has a lot of communications ports for performing science and technology missions. However, the top level system requirements for the NEXTSat-1 are mass and volume limitations. Normally, the communications for units shall be conducted by using point to point link which require more mass and volume to interconnect. Thus, our approach for the novel communications link in the NEXTSat-1 program is to use CAN and serializer and deserializer low voltage differential signal (SerDesLVDS) to meet the system requirements of mass and volume. The CAN Bus and SerDesLVDS were confirmed by using already defined communications link for our missions in the NEXTSat-1 program and the analysis results were reported in this study in view of data flow and size analysis.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제13권4호
• /
• pp.272-281
• /
• 2013

This paper presents low power frequency shift keying (FSK) transmitter using all digital PLL (ADPLL) for smart utility network (SUN). In order to operate at low-power and to integrate a small die area, the ADPLL is adopted in transmitter. The phase noise of the ADPLL is improved by using a fine resolution time to digital converter (TDC) and digitally controlled oscillator (DCO). The FSK transmitter is implemented in $0.18{\mu}m$ 1-poly 6-metal CMOS technology. The die area of the transmitter including ADPLL is $3.5mm^2$. The power consumption of the ADPLL is 12.43 mW. And, the power consumptions of the transmitter are 35.36 mW and 65.57 mW when the output power levels are -1.6 dBm and +12 dBm, respectively. Both of them are supplied by 1.8 V voltage source. The frequency resolution of the TDC is 2.7 ps. The effective DCO frequency resolution with the differential MOS varactor and sigma-delta modulator is 2.5 Hz. The phase noise of the ADPLL output at 1.8 GHz is -121.17 dBc/Hz with a 1 MHz offset.

• 실천공학교육논문지
• /
• 제10권2호
• /
• pp.81-87
• /
• 2018

통신망을 이루는 주요 구간 중에 전송망에 해당하는 네트워크 구간에 대하여 소프트웨어 정의 네트워크 제어 기술은 네트워크 산업에 걸쳐 네트워크 운용 및 프로비저닝을 활용한 네트워크 제어 환경의 변화로 자리 잡아가고 있다. 현재 PTN 장비의 보급화와 함께 개발을 추진하고 있으며 프로비저닝을 위한 구성을 단계적으로 수행하고 있다. 실제 상용망의 PTN 장비를 주축으로 프로비저닝을 구성하면서 SDN기반 제어 시스템 구축을 적극적으로 도입하고 있다. 따라서 본 논문에서는 PTN을 주축으로 하는 패킷 기반 전송망에서의 SDN 시스템에 대한 내용과 동향을 살펴보고 SDN을 구성하기 위한 오픈소스인 OpenDaylight에 대한 연구를 통해 실제 상용망에서 활용하고자 하는 핵심 기술에 대해서 연구한다. 그리고 운영자들을 대상으로 운영 교육 모델에 필요한 소프트웨어 정의 제어 기술에 대해 연구한다.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1997년도 추계학술대회
• /
• pp.188-192
• /
• 1997

The purpose of this study are changing wired medical instrument's terminal into wireless and implementing BSS of Wireless Local Area Network. the wireless terminal using frequency hopping spread spectrum in ISM band transfers patients medical information data such as ECG data, Patient Disease Indication Message to AP(or Server) and it also performs that as a response of transmission request in server. we made Clinet-Server network structure support only BSS service and patient's terminal controlled by polling in server. Wireless Terminal will guarantee mobility and give doctors real time monitoring capability in office.

• 한국항행학회논문지
• /
• 제10권3호
• /
• pp.268-275
• /
• 2006

가정과 사무실 정보 응용 및 서비스의 급격한 확산은 광대역 근거리 멀티미디어 통신을 가능하게 하는 새로운 무선 기술을 필요로 하고 있다. 고품질 미디어와 고속의 무선 연결을 위한 요구에 의하여 IEEE 표준화 그룹은 WPAN을 위한 고속 물리 계층을 고려하고 있다. 협대역의 펄스 전송을 기반으로 하는 UWB 다중 접속 기술은 고속의 서비스 제공, 낮은 전력 소모, 정확한 측위를 제공할 수 있는 응용 중의 하나이다. 본 논문에서는 전력 제어된 UWB 디바이스로 구성된 무선 센서 네트워크에서 페이딩 환경에 대한 UWB의 BER 성능을 평가하기 위한 방법론을 제시한다. 얻어진 결과는 주어진 네트워크 구조에 따른 성능 분석을 위하여 사용될 수 있으며 UWB 홈 센서 네트워크를 위한 유용한 디자인 아이디어를 제공할 수 있다.