• ETRI Journal
• /
• v.34 no.2
• /
• pp.199-209
• /
• 2012

In transport networks, a multi-ring architecture is very useful to facilitate network planning and to design and provide more resilient services for customers. Unlike traditional synchronous optical network multi-rings, the service resiliency of Ethernet-based multi-rings is significantly impacted by the ring hierarchy because a link or node failure in a certain level ring triggers filtering database flush actions in all higher level rings as well as in the ring with the failure, and consequently a large amount of duplicated data frames may be flooded. In this paper, we investigate how the ring hierarchy impacts the service resiliency of multi-ring networks. Based on extensive experiments on various single- and multiple-link failures, we suggest two effective inter-ring connection rules to minimize the transient traffic and to ensure more resilient multi-ring networks. In addition, we consider a flush optimization technique called e-ADV, and show that the combination of e-ADV and multi-ring structures satisfying our inter-ring connection rules results in a more attractive survivability performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.533-534
• /
• 2008

This paper presents a multi-phase ring VCO for low-cost, low-power GPS receiver. In the RF band used in GPS, L1 band is now in commercial-use and L2,L5 are predicting to be commercial-use soon. Thus Wide band PLL and Cost-effective IC solutions are required for future multi-band GPS receiver that received three types band at once. A new PLL architecture for multi-band GPS application is proposed. Ring VCO is even smaller than LC-VCO and a good alternative for low-cost solution. Proposed multi-phase ring VCO offers wide frequency range covering L1, L2, and L5 band, 20% reduction of area, 23% reduction of PLL power and can generate I/Q without extra I/Q generator.

• Korean Management Science Review
• /
• v.26 no.3
• /
• pp.1-9
• /
• 2009

In this paper, we present mathematical models for the ring covering problems arising in the design of multi-ring WDM networks. Also, we present efficient algorithms to solve the suggested models. By the computational experiment, our model can solve the medium-sized networks efficiently and shows better performance than the existing heuristic method. Although we propose an efficient method for the column generation procedure, branching rule that does not destroy the column generation structure is unsolved. Further research is required to develop an effective branching rule.

• Journal of the Korea Society of Computer and Information
• /
• v.22 no.10
• /
• pp.55-62
• /
• 2017

In this paper, we proposes a multi-ring based mobile sink location scheme for solar-powered wireless sensor network (WSN). The proposed scheme maintains the multi-rings in which nodes keep the current location of sink node. With the help of nodes in multi-rings, each node can locate the sink node efficiently with low-overhead. Moreover, because our scheme utilizes only surplus energy of a node, it can maintain multiple rings without degrading any performance of each node. Experimental results show that the proposed scheme shows much better latency and scalability with lower energy-consumption than the existing single-ring based scheme.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.671-674
• /
• 2004

This paper presents design and analysis of multi-layered ring-dot type piezoelectric transformer. These transformers are useful for step up and step down. The transformers consist of disk type multi-layered piezoelectric ceramic plates. The finite element method(FEM) was used for analysis transformer. Vibration mode, electric field and equivalent elastic strain of piezoelectric transformer were simulated by changing frequency. As results, the strain was distributed in isolation part entirely. We can get the operated in step up transformer when the inner side electrode using by input parts. Also we can get the step down transformers using by input Part as outer side electrode. The step up ratio and step down ratio was increased by decreasing inner side electrode. The resonance frequency was increased by increasing inner side electrode when the transformer was operated in step down transformer. But the step up one was decreased. From these results, we can expect to multi-layered ring-dot type piezo transformers as step up and step down transformers.

• Journal of the Korean Institute of Gas
• /
• v.16 no.5
• /
• pp.52-57
• /
• 2012

This study presents sealing characteristics of multi-contact o-rings as functions of strain, compression stress, and contact normal stress using a FEM technique. The FEM results on the sealing characteristics show that the maximum strain, maximum compression stress, and maximum contact normal stress of multi-contact o-rings are approximately 1.7 times higher than those of conventional o-rings. This is due to a U-grooved cross section of multi-contact o-rings, and the multi-contact o-rings with a U-groove show more effective in sealing for high pressure vessels, valves, and gas equipments. And the extrusion failure in the multi- contact o-ring does not produce for an increased gas pressure due to a U-groove. This may extend sealing life compared to that of a conventional o-ring.

• Journal of IKEEE
• /
• v.15 no.2
• /
• pp.157-163
• /
• 2011

In this paper, novel traffic groomming algorithms are proposed with a primary goal for maximizing throughput in WDM Multi-ring networks. To achieve this goal, we design four network topologys that are ITG, STG, MTG, PMTG and simulate the throughput in uniform traffic environments. From this methods, we proposed novel traffic groomming algorithms to maximize throughput in WDM Multi-ring networks.

• Journal of the Korean Institute of Gas
• /
• v.18 no.4
• /
• pp.51-55
• /
• 2014

This paper was analyzed for a sealing characteristics of single lip contact type o-ring and multiple lip contact type packing for a swivel joint using the finite element method. According to the FE analysis, a conventional o-ring produces a maximum contact normal stress of 2.5MPa for a supplied LP gas pressure of 1.8MPa, which is related to the sealing performance. But, a sealing performance of newly invented multi-lip packing produces a maximum contact normal stress of 3.01MPa, which is 20.4% higher than that of a conventional o-ring. And an extrusion of a conventional o-ring, which is strongly related to the sealing endurance safety, was occurred at a supplied gas pressure of 1.62MPa. But, a multi-lip packing does not produce up to the gas pressure of 1.8MPa. This means that a new type of multi-lip packing may have excellent sealing characteristics because of no extrusion for high gas pressure. Thus, multi-lip packing with multiple lip contacts may be useful for high sealing and endurance safety compared to that of the conventional o-ring with a single lip contact.

• Journal of Sensor Science and Technology
• /
• v.28 no.2
• /
• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.340-343
• /
• 2003

This paper presents characteristics of piezo transformer for AC-DC converter. This transformer uses transverse vibration mode and the origin of the structure was the ring dot type transformer. Because, the ring dot type transformers produce only step-up phenomenon, we made a multi-layered ring dot structure for a step-down output. The characteristics of the transformer were simulated by using the ANSYS. And frequency and voltage were measured by changing the load resistance and current. Frequencies that have the maximum output voltage and current were gradually increased, when the resistance were increased. Output voltage and current show a stable linearity according to the input voltage. The maximum output power was expected greater than 20 [W]. So, we expect that this type of multi-layered step-down ring dot transformer can be adopted for a small AC adapters.