• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.7
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• pp.925-930
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• 2013

The fault current of the power transmission system is greater than that of the power distribution system. Therefore, the introduction of superconducting fault current limiter (SFCL) is more needed to reduce the increased fault current. The trigger-type SFCL consists of the high-temperature superconducting element (HTSC), the current limiting reactor (CLR) and the circuit breaker (CB). The trigger-type SFCL can be used to supplement the disadvantages of the resistive-type SFCL. The operation characteristics of the current ratio differential relay which is usually applied to the protection device of the power transmission system are expected to be affected under fault conditions and the applicability of the trigger-type SFCL. In this paper, we analyzed the operating characteristics, by the fault conditions, between the current ratio differential relay for line protection and the trigger-type SFCL in the power transmission system through the PSCAD/EMTDC simulation.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.1 s.139
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• pp.34-42
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• 2005

An overview of 30 feet sailing yacht design is presented, with an emphasis on the factors contributing to start-up popularization. After prescribing the configurations of the purposed yacht, the design of the hull form with a rudder and a keel, are schematically described. Also the determinations of the dimensions of the sail and rig are performed. Finally this paper is associated with the state-of-the-art of calculating sailing yacht performance as this is performed in velocity prediction program (VPP). The VPP results shows a typical shape of a sailing yacht and the designed yacht has the best performance at 120 degree angle of true wind with 20 knots.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.1 s.139
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• pp.50-56
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• 2005

The performance of Traditional Korean Fishing Boat is surveyed based on Report on Investigation of Korean Fishing Boat. The characteristics of Traditional Korean fishing Boat of hull form, rudder, sail are studied from the view point of modern sailing boat design. As a result we find her hull form is an excellent candidate of mother ship for modern boat design and the great sized rudder of Traditional Korean Fishing Boat makes a role of the centerboard of modern sailing host. And also we find the sail of Traditional Korean fishing Boat is more useful for sailing against the wind direction than an ordinary Lug sail.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.156-163
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• 1998

The ATM network provides ATM CES(Circuit Emulation Services) with AAL1 for CBR(constant bit rate) services such as telephone speech. In this study, quality assessment of telephone speech with CES over ATM was performed and discussed. For this, interoperability between ATM network and structured/unstructured DS1 link was modeled for simulation. And for qualiy assessment of telephone speech, SNR and MOS were used as an objective and a subjective measure, respectively. Experimental results have shown that MOS score 4 as well as SNR 30dB could be obtained at CLR of $10^{-3}$ or below for speech signal.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.4
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• pp.308-316
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• 2011

Although a yacht sails operate with large displacement due to very thin thickness, many studies for flow around yacht sails have not considered the sail deformation. The sail deformation not only caused a change in the center of effect(CE) on the sail but also a change in the thrust of the sail. The change of the CE and thrust affects the center of lateral resistance(CLR) and side forces of the hull, and the balance of the yacht. These changes affect the motion of the yacht which changes the velocity of the yacht. Thus, when analyzing the flow around yacht sails, the sail deformation should be considered. In the present study, fluid-structure-interaction(FSI) analysis of a two dimensional section of yacht sails was performed to consider the effects of sail deformation on the lift and drag performance. FSI and moving mesh methods were studied. Computational methods were verified using benchmark test cases such as the flow around horizontal and vertical cantilever beams. Shape deformation, pressure distribution, lift forces and separation flow were compared for both rigid and deformable sail.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.2
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• pp.1-5
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• 2002

In this paper, a concatenated turbo and BCH coding is proposed for the wireless ATM cell transmission and the bit error rate(BER) and the cell loss ratio(CLR) for the Nosed system is obtained. Turbo code with code rate of 1/2 and BCH code with error correction capability of 5 and 15 bits are used in the simulations. It is shown that the proposed system obtained about 0.2 and 0.4 ㏈ gain over the conventional Turbo code at bit error rate of 0.001. Also the proposed system obtained about 0.1 and 0.2 ㏈ gain over the conventional Turbo code at cell loss rate of 0.01.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.79-83
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• 2004

The purpose of ATM traffic management is to protect the network using minimum resources and guarantee the requred QoS and also it is desirable to provide fairness between input channels. In this paper, we propose the TBBM(threshold based buffer management) algorithm to improve fairness between input channels and utilization of ATM networks. TBBM algorithm controls output cell rate dynamically based on threshold. The result shows that the required bandwidth of the TBBM algorithm is 14.3% lower in audio traffic and 41.8% lower in video traffic than that of theoretically calculated equivalent capacity method. and also reveals that the TBBM algorithm provide improved CLR fairness between input channels

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.159-164
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• 2010

We experiment to analyze on current limiting and recovery characteristics of trigger type SFCL as the composition of the contact. Generally, some superconductor of SFCL is relatively largely loaded due to limit the fault current by oneself and recovery time is affected until the fault cleared. However, in the fault, the proposal trigger type SFCL transfer the fault current to current limiting reactor(CLR) using power switch so it could reduce the recovery time and load of the superconductor. However, because of applying the additional power switches, that could generate some power loss. Therefore, to solve this problem, we proposed the composition method of the double contact for a trigger type SFCL and analyzed on current limiting and recovery characteristics for ones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12C
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• pp.181-189
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• 2001

In this thesis, a policing algorithm is proposed, which is one of the traffic management function in ATM networks. The proposed algorithm minimizes CLR(Cell Loss patio) of high priority cells and solves burstiness problem of the traffic caused by multiplexing and demultiplexing process. The proposed algorithm has been implemented with VHDL and is divided into three parts, which are an input module, an UPC module, and an output module. In implementation of the UPC module\`s memory access, memory address is assigned according to VCI\`s LSB(Lowest Significant Byte) of ATM header for convenience. And the error of VSA operation from counter\`s wrap-around can be recovered by the proposed method. ANAM library 0.25 $\mu\textrm{m}$ and design compiler of Synopsys are used for synthesis of the algorithm and Synopsys VSS tool is used for VHDL simulation of it

• Communications for Statistical Applications and Methods
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• v.31 no.3
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• pp.349-363
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• 2024

Compositional data refers to data where the sum of the values of the components is a constant, hence the sample space is defined as a simplex making it impossible to apply statistical methods developed in the usual Euclidean vector space. A natural approach to overcome this restriction is to consider an appropriate transformation which moves the sample space onto the Euclidean space, and log-ratio typed transformations, such as the additive log-ratio (ALR), the centered log-ratio (CLR) and the isometric log-ratio (ILR) transformations, have been mostly conducted. However, in scenarios with sparsity, where certain components take on exact zero values, these log-ratio type transformations may not be effective. In this work, we mainly suggest an alternative transformation, that is the square-root transformation which moves the original sample space onto the directional space. We compare the square-root transformation with the log-ratio typed transformation by the simulation study and the real data example. In the real data example, we applied both types of transformations to the USG% data obtained from NBA, and used a density based clustering method, DBSCAN (density-based spatial clustering of applications with noise), to show the result.