• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 B
• /
• pp.540-542
• /
• 1999

We develop jumping ring system with sensor and control system using dynamic neural networks. Jumping ring, sensor and control system are controlled by 586 PC using Turbo C program. Sensor system is composed of 20 optical sensors and encoder. The control circuits are consisted of thyristor, FET and phase controller. A/D converter and optical sensor acquire real time motion data of the jumping ring system. The information of acquired jumping ring Position is estimated by using dynamic neural networks. Estimated control signals are sent to control circuits and D/A converter to track desired position of the jumping ring system. Experiment results are given to verify that proposed dynamic controller is useful in real jumping ring system.

• 센서학회지
• /
• 제28권2호
• /
• pp.121-126
• /
• 2019

The voltage-controlled oscillator is one of the fundamental building blocks that determine the signal quality and power consumption in RF transceivers for wireless sensor networks. Ring oscillators are attractive owing to their small form factor and multi-phase capability despite the relatively poor phase noise performance in comparison with LC oscillators. The phase noise of a ring oscillator can be improved by using a coupled structure that works at a lower frequency. This paper introduces a 2.4 GHz low-noise ring oscillator that consists of two 3-stage coupled ring oscillators. Each sub-oscillator operates at 800 MHz, and the multi-phase signals are combined to generate a 2.4 GHz quadrature output. The voltage-controlled ring oscillator designed in a 65-nm standard CMOS technology has a tuning range of 800 MHz and exhibits the phase noise of -104 dBc/Hz at 1 MHz offset. The power consumption is 13.3 mW from a 1.2 V supply voltage.

• 전기전자학회논문지
• /
• 제15권2호
• /
• pp.157-163
• /
• 2011

본 논문에서는 WDM 기법을 이용한 멀티링 네트워크 환경에서 트래픽 전송효율을 최대화하기 위한 트래픽 그루밍 알고리즘을 제안하였다. 이를 위하여 멀티링 네트워크를 독립적, 분리적, 혼합적, 부분혼합적 구조로 나누어서 설명하였고 균등 트래픽 환경에서 성능을 평가하였다. 이를 통해 WDM 멀티링 네트워크 구조에서 트래픽 전송효율을 최대화할 수 있는 트래픽 그루밍 알고리즘을 제시하였다.

• ETRI Journal
• /
• 제29권1호
• /
• pp.116-119
• /
• 2007

In this letter, we design a collision resolution protocol for optical burst switching ring networks to avoid burst collision. We define the offset time condition for no burst transmission collision and manage the free time list of nodes for no burst reception collision. In order to improve the throughput, we use a fiber delay line, void-filling, and void-compression. This protocol does not require any additional procedures for bandwidth reservation such as centralized assignment of bandwidth, lightpath setup of WDM ring networks, or token capturing for the burst transmission. The simulation results show that the proposed protocol can achieve high throughput while saving 70% of wavelengths when compared to round robin with random selection, round robin with persistent, and round robin with non-persistent with only destination delay.

• 한국경영과학회지
• /
• 제32권4호
• /
• pp.51-60
• /
• 2007

In this study, we consider the minimum ADM problem which is the fundamental problem for the cost-effective design of SONET ADM embedded in WDM ring networks. To minimize the number of SONET ADMs, efficient algorithms for the routing and wavelength assignment are needed. We propose a mathematical model based on the graph theory for the problem and propose a branch-and-price approach to solve the suggested model effectively within reasonable time. By exploiting the mathematical structure of ring networks, we developed polynomial time algorithms for column generation subroutine at branch-and-bound tree. In a computer simulation study, the suggested approach can find the optimal solution for sufficient size networks and shows better performance than the greedy heuristic method.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제9권5호
• /
• pp.1606-1623
• /
• 2015

Optical switching will be applied in datacenter networks because electronic switching is costly and power-consuming. In this paper, considering the ring-based interconnection using optical switching in the core of a datacenter, we study the home circuit (HC) construction for the labeled optical burst switching with home circuit (LOBS-HC), a new paradigm trying to share wavelengths among the HCs from the same source. In particular, aiming to construct HCs dynamically and properly, a scheme named optimal path matching and symmetric HC matching (OPM-SHM) is proposed. The main idea of OPM-SHM is to dynamically construct HCs by sharing wavelength(s) not only among the same-source HCs but also with symmetric HCs which have different sources other than the original LOBS-HC features. The simulation results demonstrate that OPM-SHM achieves better performance than some other methods in terms of burst loss rate and wavelength utilization of physical links. More specially, it maintains good load balancing for the datacenter network using an LOBS-HC ring. In addition, due to the symmetric feature of SHM, the proposed scheme can decrease the upper bound of the average hop count of the routing paths to half of the ring size.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
• /
• pp.135-138
• /
• 2004

This paper considers a ring loading problem on RPR(Resilient Packet Ring), where RPR is recommended by IEEE802.17 Resilient Packet Ring working group for data optimized networks without the requirements of provisioning circuits. RPR is well suitable for metropolitan area network with two counter-rotating rings that multiple stations share the bandwidth, where the data and its corresponding control traffic is transmitted to the two opposite directional ring, respectively. One of the major concerns on RPR is to provide fairness among traffic requirements. The paper discusses several fairness measures and analysis ring loading problems for the fairness.

• 대한산업공학회지
• /
• 제22권2호
• /
• pp.255-263
• /
• 1996

Optical fiber systems play an essential role In today's telecommunications networks. The recently standardized SONET technology has made a ring structure the preferred architecture for inter-city communication networks. In designing a SONET with ring structure, we consider inserting optional cites, which are not necessary in constructing the SONET, but cost-effective in connecting essential nodes in the ring. This problem is modeled as Steiner ring problem. Efficient heuristic procedures are developed based on the procedures for the traveling salesman problem. Computational results show that the proposed algorithm is excellent compared to the optimal solution. The error bound by the proposed method is 2 - 6% in experimented problems.

• International Journal of Contents
• /
• 제5권4호
• /
• pp.88-93
• /
• 2009

It is important for communication networks to possess the capability to overcome failures and provide survivable services. We address modeling and analysis of performability affected by both performance and availability of system components for a token ring network under failure and repair conditions. Stochastic reward nets (SRN) is an extension of stochastic Petri nets and provides compact modeling facilities for system analysis. In this paper, hierarchical SRN modeling techniques are used to overcome state largeness problem. The upper level model is used to compute availability and the lower level model captures the performance. And Normalized Throughput Loss (NTL) is obtained for the composite ring network for each node failures occurrence as a performability measure. One of the key contributions of this paper constitutes the Petri nets modeling techniques instead of complicate numerical analysis of Markov chains and easy way of performability analysis for a token ring network under SRN reward concepts.

• 한국통신학회논문지
• /
• 제25권1B호
• /
• pp.15-30
• /
• 2000

광전송망은 망의 장애에 미리 대비할 수 있도록 신뢰성과 생존도를 고려하여 설계하여야 한다. 동기식 다중화의 국제표준인 SDH(Synchronous Digital Hierarchy) 방식의 광전송망은 장애 발생시 이를 자동적으로 복구할 수 있도록 생존도를 고려한 여러 가지 망 재구성 기법들을 제공한다. 그 중 SHR(Self-Healing Ring)은 링의 형태로 망을 구성한 시스템으로 뛰어난 생존도와 경제성으로 통신사업자들의 기간통신망 구조로 활발히 채택되고 있다. 이 때, 링들이 설치되는 지역적 범위가 넓어지고 수요가 증가되면, 다수의 링들이 중첩되어 상호연결되는 다중링(Multi-ring) 구조로 발전하게 된다. 본 연구에서는 수요의 분할처리를 허용하는 BSHR(Bidirectional SHR)들이 연접한 다중링 설계 문제를 다룬다. 이 문제는 망구축용량을 최소로하는 관점에서 생존도가 보장되는 부하 최적화 문제가 되며, 혼합정수계획법에 의한 정식화가 가능하다. 그러나, 현실문제에서는 망구축용량의 최소화 뿐만아니라 노드가 수요로 다계위 수요가 주어지며 중계노드에서의 다중화 번들링도 같이 고려되어야 하므로 수리모형으로는 해결할 수 없는 복잡한 문제가 된다. 따라서 이 叩걋\ulcorner고려사항들을 반영한 최적근사해를 실시간내에 구할 수 있는 휴리스틱 알고리즘을 개발하게 되었다. 사례연구에서는 휴리스틱 알고리즘을 적용한 실제 망설계 문제를 설명하였고, 망구성 방법에 따른 차이와 다중화 번들링 여부로 인한 실험 결과를 비교하였다.