• Journal of Navigation and Port Research
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• v.36 no.5
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• pp.409-418
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• 2012

Amid global economic crisis and skyrocketing oil prices, container shipping companies have raised a sustained series of efforts to reduce vessel operating costs. Under these circumstances, the Grand Alliance has decided to install the dedicated feeder instead of additional vessels in the CCX(Central China Express) and the NCE(North China Express) route. In other words, a vessel in a trunk route is transshiped by a dedicated feeder vessel in Busan port that is a transshipment port, rather than calling at Northen China port. In this study, the actual operating data of Grand Alliance container services were analyzed to determine the economic effect of transshipment through a dedicated feeder service. In this way, the Grand Alliance are saving vessel operating expenses in 'NCE' and 'CCX' routes, making the slow steaming of vessels possible in these trunk routes.

• The Journal of Information Technology
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• v.2 no.2
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• pp.199-215
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• 1999

A quantitative analysis was conduct on the economic effect of electronic commerce according to the method of constructing the internet. As a consequence, it was information retrieval cost that had the most cost retrenchment effect in connecting the internet by telephone, which saved about 353,700 won. And it was found that the dedicated line to electronic commerce saved 420,600 won of information retrieval cost and a considerable amount of 319,900 won of brokerage expenses and physical distribution expenses. In terms of value, it was found that the telephone line reduced the time of order process by 8.25%, whereas the dedicated line did so by 9.41% and therefore saved more time than the telephone line. It was found that the dedicated line convenient to use had the higher effect by about 1.2%, respectively than the telephone line in terms of the effective construction of corporate image and the increase of potential buyers. In terms of business management, the intensification of corporate competitiveness improved by 10.00% in case of less than 10 times and by 11.53% in case of 50 to less than 50 times. And it was found that the effect of profit increase as the number of inquiries was large. That is, it was found that the effect of profit increase was 10.88% when the number of inquiries was less than 10 times but it increased to 14.00% in case of 50∼1ess than 100 times. The limitation of this study is that because the size of samples through mail, interview and E-mail was not large, its results have some limitation in applying them to every firm. That is, since the improvement effect of the intrafirm business method, unnecessary repeated manual paperwork and the use effect of being able to maintain the close relationship with to the parties to trades in the process of prompt receipt and delivery of documents are long-term and indirect effects, they have some limitation in that they can not be measured as coefficients but only as scales. Thus, firms using electronic commerce have difficulty enjoying a uniformly identical effect. Therefore, to revitalize electronic commerce, it is thought that government, the academic community and the business world all need to make much research into and sustained investment in electronic commerce.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.903-906
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• 1987

The digital private line network provides synchronous data communications over dedicated facilities at several speeds. This service became available to several major metropolitan areas in 1986 with speeds of 4800, 9600, 56000 b/s. The network is expected to grow to include many city areas. In this paper, synchronization plan for the network is proposed.

• Journal of the Korean Society for Railway
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• v.16 no.6
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• pp.551-557
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• 2013

This research aims to conduct a study on the feasibility of the LTE communication method for developing a dedicated integrated railway wireless network. An empirical analysis was carried out by establishing a dedicated integrated railway wireless network in an approximately 12km section between Illo station and Daebul station on the Honam line. Korean wireless communication methods for railway safety are different depending on each line, which makes it difficult for railway workers to cooperate with. This causes various problems. There is the ever-present risk of accidents due to call disconnection between wireless communication systems, frequency interference from commercial networks, and crosstalk. This study verified the feasibility of the 4th generation communication system, LTE, over the dedicated integrated railway wireless network as a solution for the above mentioned problems. The result shows this communication system exceeded existing performance standards of Europe GSM-R in every test item despite the location constraint of train tracks on the base station establishment.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.2
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• pp.156-166
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• 2024

This paper conducts a study on methods for associating multipath tracks received by a horizontal line array sonar. The horizontal line array sonar introduces conical bearing ambiguities due to its array-shaped characteristics. Target signals are often subject to multipath propagation in the ocean, resulting in errors in target bearing estimation due to these bearing ambiguities. Recent research efforts have been directed toward using multipath tracks to estimate the positions of targets. However, there has been a lack of research dedicated to identifying multipath tracks from the measurements of a horizontal line array sonar. Therefore, this study identifies the conical bearing characteristics of multipath signals based on the result of experiment and establishes criteria for associating multipath tracks. Additionally, Simulations are performed to determine the ability to associate multipath tracks.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.145-146
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• 2011

A micro-grid (MG) is usually interconnected to the main grid through the dedicated line. Immediately after the removal of the grid supply, the MG should be disconnected and remain disconnected until the main grid is re-energized. It should detect islanding condition as soon as it happens to adjust the setting of the protection relays in the MG. This paper proposes an islanding detection algorithm for the MG based on the active and reactive power delivered to the dedicated line in the time domain. The performance of the proposed algorithm is verified under islanding conditions and fault conditions using the PSCAD/EMTDC simulator. The results indicate that the proposed algorithm can discriminate the islanding conditions from the various fault conditions.

• KIEE International Transactions on Power Engineering
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• v.3A no.4
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• pp.198-205
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• 2003

This paper proposes the adaptive relaying of protective devices applied in the neighboring distribution feeders for reliable and efficient operations of a wind farm interconnected with distribution networks by dedicated lines. A wind farm connected to an electric power network is one of the greatest alternative energy sources. However, the wind turbine generators are influenced by abnormal grid conditions such as disturbances occurring in the neighboring distribution feeders as well as the dedicated power. Particularly, in cases of a fault happening in the neighboring distribution feeders, a wind farm might be accelerated until protective devices clear the fault. Therefore, the delayed operation time of protective devices for satisfying the coordination might overly expose the interconnected wind turbine generators to the fault and cause damage to them. This paper describes the proper delayed operation time of protective relay satisfying the coordination of the distribution networks as well as reducing damage on the interconnected wind farm. The simulation results for the Hoenggye substation model composed of five feeders and one dedicated line using PSCAD/EMTDC showed that the proper delayed time of protective devices reflecting the fault condition and the power output of the wind farm could improve the operational reliability, efficiency, and stability of the wind farm.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.22-32
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• 2021

To meet rapidly changing market demands, manufacturers strive to increase both of productivity and diversity at the same time. As a part of those effort, they are applying flexible manufacturing systems that produce multiple types and/or options of products at a single production line. This paper studies such flexible manufacturing system with multiple types of products, multiple Bernoulli reliability machines and dedicated buffers between them for each of product types. As one of the prevalent control policies, priority based policy is applied at each machines to select the product to be processed. To analyze such system and its performance measures exactly, Markov chain models are applied. Because it is too complex to define all relative transient and its probabilities for each state, an algorithm to update transient state probability are introduced. Based on the steady state probability, some performance measures such as production rate, WIP-based measures, blocking probability and starvation probability are derived. Some system properties are also addressed. There is a property of non-conservation of flow, which means the product ratio at the input flow is not conserved at the succeeding flows. In addition, it is also found that increased buffer capacity does not guarantee improved production rate in this system.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1757-1762
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• 2003

For coping with various ship types easily, welding automation using CAD/CAM is demanded and and developed. In this paper we propose a dedicated CAM system which generates MACRO files to control robot manipulators. The paper contains CAD interface, virtual simulation, macro generation and job schedulling. At first, it defines and extracts weldline from CAD data, and generates proper MACRO programs. And it obtains optimum job schedules. This system removes the manual work, and consequently reduces the overall lead time. And it reduces costs and time for developing robot welding programs. This can be expanded to virtual factory simulation technology. Moreover, it is possible to apply this system for automation of Cutting and Painting

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.338-341
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• 2003

This paper proposes the adaptive relaying algorithm of protective devices applied in the neighboring distribution feeders for reliable and efficient operations of a wind farm interconnected with distribution networks by dedicated lines. Generally, it would be highly possible that the wind turbine generators are influenced by abnormal grid conditions such as disturbances occurring in the neighboring distribution feeders as well as the dedicated power line. The delayed operation time of protective devices for satisfying the coordination might overly expose the interconnected wind turbine generators to the fault and cause damage to them. In order to reduce the damages on the interconnected wind farm about the faults happening in distribution networks, this paper describes the proper delayed operation time of protective relay.