• Proceedings of the Korean Society of Computer Information Conference
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• 2011.01a
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• pp.109-110
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• 2011

Because contemporary rolling stock system is complex and highly advanced, and it builds mutual interface, it is necessary to manage maintenance of rolling stock systematically. This study present a case, which shows how to adopt and apply RTD(Remote Transmission Device) integrated to train information collection device. After the train service is complete and the train enters the main subway station, various kinds of information collected from TCMS(Train Control Monitoring System) is transmitted to train depot information collection device through RTD. This study suggests that RTD integrated to train information collection device helps build an effective rolling stock maintenance system by improving reliability of data transmission and cutting maintenance costs.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.11
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• pp.549-557
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• 2000

This study proposes a new numerical analysis method for assessing the outage cost of the composite power system with considering transmission system at load points. The proposed method comes from combination of the expected energy not served curve(EENSC) with the marginal outage cost function obtained at load points. Uncertainty of the outages of the generation and transmission systems was also included in this study. This study can be categorized into three processing parts as like as follows. Firstly, EENSC at load points was developed newly from the composite power system effective load duration curve which has been proposed by the authors. Secondly, this study proposes a new technical method for determining the coefficients of the marginal outage cost functions at load points in the composite power system(Generation and Transmission systems). It is a main key point that the mathematical expression for the marginal outage cost function at a load point is formulated and evaluated using relations between the GNP (or GDP) and the electrical energy demand at the load pint. Finally, the outage cost was calculated in this paper by combining the proposed EENSC with the marginal outage cost function evaluated at each load point. It is another important feature that the average costs for future at load points can be forescasted using the proposed approach. The effectiveness of the proposed new approach is demonstrated by the case studies with the IEEE-RTS.

• Journal of Korea Multimedia Society
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• v.18 no.1
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• pp.25-34
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• 2015

Recently, in distribution market, demand for electronic shelf label system is increasing gradually to provide the accurate price immediately and detailed product information to consumers and reduce operation costs. Most of electronic shelf label system companies develop the full-graphic display device to display a wide variety of product information as well as the exact price. Our system had introduced Go-Back-N retransmission method in the early. However, we encountered performance problems that it delayed updating of the electronic shelf label system and exhausted the battery life time. Proposed adaptive image retransmission technique based on the selective scheme is that tags of electronic shelf label system recognize idle time of transmission cycle and require partial image retransmission to sever by itself. As a result, it can acquire much more opportunities of partial image retransmission within the same period and increase reception rate of full image for each tags. The experimental result shows that adaptive image retransmission technique's reception rate of full image for each tags is approximately 4% higher than existing previous works. And total battery life time increases 30 hours because tag reduce wake-up time as it receive only lost data instead of whole data.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.5
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• pp.329-339
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• 2019

Recently, the advancement of information and communication technology(ICT) is expanding the connectivity through Internet of Things(IoT), and the media of connection is also expanding from wire/cable transmission to broadband wireless communication, which has significantly improved mobility. This hyperconnectivity has become a key element of the fourth industrial revolution, whereas the supervisory control network of purification plants in korea is operated as a communication network separated from the outside, thereby lagging in terms of connectivity. This is considered the best way to ensure security, and thus there is hardly any consideration of establishing alternatives to operate an efficient and stable communication network. Moreover, security for management of a commercialized communication network and network management solution may be accompanied by immense costs, making it more difficult to make new attempts. Therefore, to improve the conditions for the current supervisory control network of purification plants, this study developed a industrial security L2 switch that supports modbus TCP(Transmission Control Protocol) communication and encryption function of the transmission section. As a result, the communication security performance improved significantly, and the cost for implementing the network management system using Historical Trend and information of HMI(Human Machine Interface) could be reduced by approximately KRW 200 million. The results of this study may be applied to systems for gas, electricity and social safety nets that are infrastructure communication networks that are similar to purification plants.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.653-660
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• 2021

Renewable energy resources are rapidly becoming an integral part of electricity generation portfolios around the world due to declining costs, government subsidies, and corporate sustainability goal. Interacting wind, solar, and load forecast errors can create significant unpredictable impacts on the distribution system, feeder congestion, voltage standard and reactive power stability margins. These impacts will be increasing with the increasing penetration levels of variable renewable generation in the power systems. There is a limit to the maximum amount of renewable energy sources that can be connected in a distribution feeder by the connection rule of transmission & distribution facility in Korea. This study represents the decision plans of hosting capacity for distribution feeders without the need for significant upgrades to the existing transmission infrastructure. Especially, the paper suggests and discusses the hosting capacity standard of feeder cables and minimum load calculation of distribution feeders.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.255-263
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• 2021

Smart grid is a fully-automated, bi-directional, power transmission network based on the physical grid system, which combines sensor measurement, computer, information communication, and automatic control technology. Blockchain technology, with its security features, can be integrated with Smart Grids to provide secure and efficient power management and transmission. This paper dicusses the deployment of Blockchain technology in Smart Grid. It presents application areas and protocols in which blockchain can be applied to in securing smart grid. One application of each area is explored in detail, such as efficient peer-to-peer transaction, lower platform costs, faster processes, greater flexibility in power generation to transmission, distribution and power consumption in different energy storage systems, current barriers obstructing the implementation of blockchain applications with some level of maturity in financial services but concepts only in energy and other sectors. Wide range of energy applications suggesting a suitable blockchain architecture in smart grid operations, a sample block structure and the potential blockchain technicalities employed in it. Also, added with efficient data aggregation schemes based on the blockchain technology to overcome the challenges related to privacy and security in the smart grid. Later on, consensus algorithms and protocols are discussed. Monitoring of the usage and statistics of energy distribution systems that can also be used to remotely control energy flow to a particular area. Further, the discussion on the blockchain-based frameworks that helps in the diagnosis and maintenance of smart grid equipment. We have also discussed several commercial implementations of blockchain in the smart grid. Finally, various challenges have been discussed for integrating these technologies. Overall, it can be said at the present point in time that blockchain technology certainly shows a lot of potentials from a customer perspective too and should be further developed by market participants. The approaches seen thus far may have a disruptive effect in the future and might require additional regulatory intervention in an already tightly regulated energy market. If blockchains are to deliver benefits for consumers (whether as consumers or prosumers of energy), a strong focus on consumer issues will be needed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.135-136
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• 2023

This study is an empirical result for building an onboard communication network using metal surface wave communication and is a consideration of its application within the ship. Over the past three years, the applicability and the performance of metal surface wave communication has been confirmed by testing on five small and medium ships. In the tests, IEEE 802.11 protocol of Wi-Fi was used, and the signals were generated in the form of surface waves. Data was sent from AP to AP in the point-to-point form, and the transmission speed was measured at the same time. If necessary, additional repeaters were used to extend the transmission distance. As derived a transmission speed of 5 to 100 Mbps in wireless communication restricted areas of the 5 ships, it is believed that it is possible to reduce the weight of ships and costs by eliminating the communication cables by using surface wave communication as the back-bone network on ships.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2011-2018
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• 2024

Since RF breakdown is one of the primary limitations to improving the performances of RF accelerators, extensive efforts have been dedicated to locating the breakdowns. However, most existing methods rely on specialized techniques, resulting in high financial burdens. Although the method based on transient response of transmission line (TL) is suitable for facilities with sporadic recoverable breakdowns, practical operations are susceptible to notable errors. This study revisits the fundamental theories of lossless TL and investigates the wave process to understand the characteristics of the reversed pulse induced by the breakdowns. By utilizing steadystate response of the TL and employing phasor method, we derive analytical formulas to determine the exact location of breakdowns within the faulty cell for constant-gradient TW accelerator. Furthermore, the derived formulas demonstrate their independence from RF phase, thereby distinguishing them from traditional phasebased methods. Additionally, experimental validations are conducted at the HUST injector, and the results confirm the consistency of the analysis. Thus, the proposed method represents a promising improvement over the TL-based approaches and serves as a valuable complement to current techniques. Importantly, this method demonstrates particular advantages for constructed TW accelerators seeking to achieve a balance among high performance, low costs, and compact layouts.

• Journal of the Korea Society of Computer and Information
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• v.22 no.4
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• pp.75-82
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• 2017

While the internet has evolved in terms of information sharing and efficiency, it is still prone to security attacks and remains vulnerable even when equipped with a security mechanism. Repeated patching against hacks involves excessive wear of system equipment and high costs. Methods of improving network security include the introduction of security equipment and network partitions, but they have not been fully effective. A fundamental solution is the Operation Content Network (OCN), which enables the strengthening of authentication. In this paper, Instead of following the existing TCP/IP system, OCN establishes an immunity-based security system through content-centric communications. Data transmission occurs over a Content Centric Network (CCN), which is provided with a protocol verified by the CCNx group. Areas protected by OCN rely only on CCN for communication without using any IP. As such, it defends the system against unknown attacks, including zero-day attacks.

• Journal of electromagnetic engineering and science
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• v.5 no.1
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• pp.36-42
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• 2005

In this paper, the optimal position of optical phase conjugator(OPC) excellently compensating distorted WDM channels with initial frequency chirp due to both chromatic dispersion and self phase modulation(SPM) is numerically investigated. Highly-nonlinear dispersion shifted fiber(HNL-DSF) is used as a nonlinear medium of OPC in order to widely compensate WDM signal band. It is confirmed that if the OPC position was shifted from mid-way of total transmission length dependence on the initial frequency chirp as well as modulation format and fiber dispersion coefficient, it is possible to cancel the performance degradation owing to the initial frequency chirp. Using proposed configuration, it is possible to remove all in-line dispersion compensator, reducing span losses and system costs in the long-haul broadband WDM systems.