• Journal of Communications and Networks
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• v.14 no.6
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• pp.653-661
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• 2012

High-availability seamless redundancy (HSR) is a redundancy protocol for Ethernet networks that provides two frame copies for each frame sent. Each copy will pass through separate physical paths, pursuing zero fault recovery time. This means that even in the case of a node or a link failure, there is no stoppage of network operations whatsoever. HSR is a potential candidate for the communications of a smart grid, but its main drawback is the unnecessary traffic created due to the duplicated copies of each sent frame, which are generated and circulated inside the network. This downside will degrade network performance and might cause network congestion or even stoppage. In this paper, we present two approaches to solve the above-mentioned problem. The first approach is called quick removing (QR), and is suited to ring or connected ring topologies. The idea is to remove the duplicated frame copies from the network when all the nodes have received one copy of the sent frame and begin to receive the second copy. Therefore, the forwarding of those frame copies until they reach the source node, as occurs in standard HSR, is not needed in QR. Our example shows a traffic reduction of 37.5%compared to the standard HSR protocol. The second approach is called the virtual ring (VRing), which divides any closed-loop HSR network into several VRings. Each VRing will circulate the traffic of a corresponding group of nodes within it. Therefore, the traffic in that group will not affect any of the other network links or nodes, which results in an enhancement of traffic performance. For our sample network, the VRing approach shows a network traffic reduction in the range of 67.7 to 48.4%in a healthy network case and 89.7 to 44.8%in a faulty network case, compared to standard HSR.

• IE interfaces
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• v.17 no.4
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• pp.472-481
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• 2004

In this paper, we propose a linear programming model of supply planning process for the supply chain collaboration strategy of a company. The amount of its supplying quantity relies on outsourcing suppliers heavily. Conversely, the revenues of those suppliers are highly dependent on the supplying quota from the supply network planning of the company. In order to keep the supply stable through collaboration, the company builds such a policy to guarantee the fairness on revenue between the supplies. For this, the supply network plan should keep the capacity utilization ratio even for all the suppliers. But the production capacities are different and the distribution of molds is disproportional through suppliers, so the supply network plan is not easily established with simple arithmetic processes. Therefore, we developed the linear programming model with those target function and constraints minimizing the costs for holding inventory and penalty of delayed delivery, simultaneously guaranteeing the even capacity utilization through suppliers. The proposed model has been applied to real case and the evaluation for the planning result from the model would be followed in order to make sure that our model guarantee on extracting the supply network plan subordinated to the policy. Also we mention about further studies for improvement of the model.

• 전기의세계
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• v.20 no.6
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• pp.7-18
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• 1971

Secondary-side transfer phenomena of primary-side surge voltage in concentric-cylindrical transformers of a high turn-ratio still present a problem in transformer insulation design even in the case of a neutral solid-grounding type. The conventional methods of analyzing them so far are much complicated for practical applications. Therefore, this paper describes a new approach to the analysis of secondary-side transfer phenomena of surge in concentric-cylindrical transformers of high turn-ratio and solid-grounding type. This generalized approach is thought to be more simple with the use of minor network concepts than the conventional one by major network only. The result shows that the secondary-side transfer phenomena of surge voltage could not be neglected even in concentric-cylindrical transformer of high turn-ratio and solid-grounding type, and will be satisfactorily applicable to the design of neutral-solid-grounding type transformers.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.473-477
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• 2001

Artificial neural network (ANN) is known to identify relationships even when some of the input data are very complex, ill-defined and ill-structured. One of the advantages in ANN is that it can discriminate the linearly inseparable data. This study presents an application of ANN to classify and predict the symptomatic status of HIV/AIDS patients. Even though ANN techniques have been applied to a variety of areas, this study has a substantial contribution to the HIV/AIDS care and prevention planning area. ANN model in classifying both the HIV and AIDS status of HIV/AIDS patients is developed and analyzed. The diagnostic accuracy of the ANN in classifying both the HIV status and AIDS status of HIV/AIDS status is evaluated. Several different ANN topologies are applied to AIDS Cost and Services Utilization Survey (ACSUS) datasets in order to demonstrate the model\`s capability. If ANN design models are different, it would be interesting to see what influence would have on classification of HIV/AIDS-related persons.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.261-264
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• 2004

We propose a location management with adaptive binding idle lifetime scheme for IP-based wireless network. In our proposed scheme, the binding idle lifetime value is adaptively varied according to user characteristics. The main idea is that the mobile node (MN) does location update (LU) even in idle state. Furthermore a sequential paging scheme is used to reduce the paging cost. The proposed scheme can be used in both cellular network and IP-based network.

• 전기의세계
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• v.27 no.4
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• pp.41-44
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• 1978

Intermittent failures exercise their effects only part of the time but constitute a dominant factor for the field failures. We consider the data raliability of the partially self-checking network with which a single intermittent failure will be recovered by a rollback method. Even if the self-testingness of partially self-checking network is guranteed for a set of permanent failures, it sometimes may not be so for intermittent failures. We introduce the notion of error residual and provide the basis for calculating the data reliability. Both the duration of each intermittent failure and the occurrence interval of successive ones are assumed to be negative exponentially distributed; the convolution of the intervals is distributed according to an Erlangen distribution.

• Journal of applied mathematics & informatics
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• v.27 no.1_2
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• pp.139-147
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• 2009

We study the neural network approximation to a function in $C^1$[0, 1] and its derivative. In [3], we used even trigonometric polynomials in order to get an approximation order to a function in $L_p$ space. In this paper, we show the simultaneous approximation order to a function in $C^1$[0, 1] using a Bernstein polynomial and a feedforward neural network. Our proofs are constructive.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.2069-2074
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• 2006

The Next generation network may describe one integrated network by IP (Internet Protocol) convergence and combining various access technologies. The IP version 6 (IPv6) becomes fundamental protocol and the terminal offered various services is having mobility, multihoming, and intelligent as well as smaller. In this convergence network, which integrate mobile network, broad cast network, and Internet as well as PSTN, can provide all of the service. In this context, we will briefly present that the end node should be required ubiquitous computing and networking. That is to say that we must guarantee the end node in any time, my place, my where, and offer continuously services to the node. As like this, Service Mobility is given if a user can obtain subscribed and personalized services consistently even if connected to a foreign network service provider. In other words, Service mobility allows users to maintain access to their services even while moving or changing devices and network service providers. In this paper, we have to refer technical consideration items to make the service mobility framework.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.35-43
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• 2019

A metro ring network using WDM technology requires many issues to be considered even though its transmission distance is shorter and its transmission capacity is lower than a long-haul WDM system. Unlike a long-haul WDM system, which is basically point-to-point configuration, a metro ring network usually equips with capabilty of wavelength reconfiguration. Therefore network performance considering crosstalk within OADM and the network behavior when the ring network is closed should be analyzed before implemented. We discussed some of results analyzed for the issues. Furthermore we proposed a novel method to design a dispersion map for a ring network, and demonstrated the methodology with an exemplary 8-node ring network of 399km circumference.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.159-179
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• 2022

Often a network becomes complex, and multiple entities would get in charge of managing part of the whole network. An example is a utility grid. While the entire grid would go under a single utility company's responsibility, the network is often split into multiple subsections. Subsequently, each subsection would be given as the responsibility area to the corresponding sub-organization in the utility company. The issue of how to make subsystems of adequate size and minimum number of interconnections between subsystems becomes more critical, especially in real-time simulations. Because the computation capability limit of a single computation unit, regardless of whether it is a high-speed conventional CPU core or an FPGA computational engine, it comes with a maximum limit that can be completed within a given amount of execution time. The issue becomes worsened in real time simulation, in which the computation needs to be in precise synchronization with the real-world clock. When the subject of the computation allows for a longer execution time, i.e., a larger time step size, a larger portion of the network can be put on a computation unit. This translates into a larger margin of the difference between the worst and the best. In other words, even though the worst (or the largest) computational burden is orders of magnitude larger than the best (or the smallest) computational burden, all the necessary computation can still be completed within the given amount of time. However, the requirement of real-time makes the margin much smaller. In other words, the difference between the worst and the best should be as small as possible in order to ensure the even distribution of the computational load. Besides, data exchange/communication is essential in parallel computation, affecting the overall performance. However, the exchange of data takes time. Therefore, the corresponding consideration needs to be with the computational load distribution among multiple calculation units. If it turns out in a satisfactory way, such distribution will raise the possibility of completing the necessary computation in a given amount of time, which might come down in the level of microsecond order. This paper presents an effective way to split a given electrical network, according to multiple criteria, for the purpose of distributing the entire computational load into a set of even (or close to even) sized computational loads. Based on the proposed system splitting method, heavy computation burdens of large-scale electrical networks can be distributed to multiple calculation units, such as an RTDS real time simulator, achieving either more efficient usage of the calculation units, a reduction of the necessary size of the simulation time step, or both.