• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1618-1623
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• 2019

In this paper, inductive couplers realizing broadband powerline communication (PLC) are fabricated using Fe-based nanocrystalline alloy and their performance is analyzed. As a result of the field tests using the distribution automation system (DAS), the couplers achieve comparatively excellent data communication in the principal frequency band of broadband PLC although there is a difference in communication rate depending on the presence or absence of a branch. In addition, it has been confirmed that the communication speed is maintained for a real-time transmission even in a high current environment although there is a difference in the transmission rate depending on the distance. Hence, it is considered that the inductive couplers can be used as a core device to realize the intelligent power network by exploiting them for the monitoring and remote controlling of the power plant equipments for the DAS located in the inaccessible areas.

• Journal of Biomedical Engineering Research
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• v.16 no.3
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• pp.353-358
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• 1995

The impedance pneumography which is widely used in monitoring respiration is simple to use and noninvasive, but it is sensitive to motion artifacts and insensitive to detect obstructive apnea. A 3-channel respiratory inductive plethysmography (RIP) developed in this study detects inductance change of the inductance band induced by cross-sectional area change of thorax or abdomen as one breathes. It was confirmed that RIP was less sensitive to various motion artifacts but more sensitive to detection of obstructive apnea than impedance pneumography.

• Journal of Korean Society of Transportation
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• v.13 no.3
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• pp.67-86
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• 1995

It requires the detector system which can collect highly reliable traffic data in order to perform the real-time traffic signal control. This study is to decide the optimal shape of inductive loop for the real-time traffic signal control .This loop is located at the stopline in the signalized intersection for DS(Degree of Saturation) control. In order to find out the optimal shape of loop, 6types of experiments were performed . The results of the basic experiments of loops are as follows ; -the optimal number of turns for loop is 3 turns. -the impedance values of the loop detectors are similar to that of NEMA standards -the 1.8${\times}$4.5M loop is excellent for sensitivity in actual detection range of car length comparing to other shape of inductive loops. At the experimental of establishments of the optimal loop shape, it found that 1.8 4.5M loop has the highest values of $\DeltaL$ comparing to other types of loops, It means that the range of Lead-in cable length of this loop. And this loop is highly reliable in occpupancy time. Conclusivley, the 1.8${\times}$4.5M inductive loop is the optimal solution as a stop line loop detector for real -time traffic signal control.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.85-91
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• 2015

We investigated the structure of inductive coupler and its magnetic coupling to increase the transmission coefficient for power line communication. A Rogowski coil, which is an air-cored inductive coupler, and a magnetic cored coupler were fabricated to analyze the transmission coefficient for different coupler parameters. This paper proposes the impedance matching method using lumped elements and an impedance transformer to increase the transmission coefficient. In the experiment, the transmission coefficient of the proposed system was increased in both narrowband and broadband cases, and a trade-off between the transmission coefficient and the bandwidth was shown. This method will be useful for the further study of impedance matching with the load variation.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.495-498
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• 2004

In this paper, passive telemetry capacitive humidity sensor system using a RLSE(Recursive Least Square Estimation) technique Is proposed. To overcome the problem like power limits and complications that general passive telemetry sensor system including IC chip has, the principle of inductive coupling is applied to model the sensor system. Specially, by applying the forgetting factor, we show that the accuracy of its estimation can be improved even in the case of time varying parameter and also the convergence time can be reduced.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1791-1793
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• 2003

In order to analyze the dynamic characteristics of ground impedance in large grounding system for lightning and surge protections, a novel method for measuring the ground impedance as a function of frequency was proposed. The experiments were carried out in the grounding system composed of ground rods and mesh grids. The test current was injected by the variable frequency inverter whose frequency is linearly controlled in the range of $5{\sim}500$kHz. The ground impedance and frequency response of the grounding system were mainly caused by the inductive current flowing through grounding conductors over the frequency of 2002. In the combined grounding system of rods and mesh grids, inductive component of ground impedance was significantly decreased. It was fumed out that the grounding system is effective for the surge protection.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.181-183
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• 1996

A novel model of an inductive superconducting fault current limiter with an inductive superconducting fault current limiter with the air-gap core was fabricated and tested. If its impedance is not high enough to limit the fault current, then destructive damage occurs in the power system. We attained a magnetic saturation under higher current by an effective air gap introduced in the core. The fault current was successfully limited to two times as much as the nominal current at a 60 Hz source having an effective voltage of 70 V. The fault current flowing under such conditions can be limited to a desired value without any fault current peak within 1/4 cycles.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.308-313
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• 1998

In this paper we will discuss a type of inductive learning called learning from examples, whose task is to induce general description of concepts from specific instances of these concepts. In many real life situations, however, new instances can be added to the set of instances. It is first proposed within the framework of rough set theory, for such cases, an algorithm to find minimal set of rules for decision tables without recalculation for overcall set of instances. The method of learning presented here is base don a rough set concept proposed by Pawlak[2][11]. It is shown an algorithm to find minimal set of rules using reduct change theorems giving criteria for minimum recalculation with an illustrative example. Finally, the proposed learning algorithm is applied to fuzzy system to learn sampled I/O data.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.5
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• pp.55-64
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• 1989

The effect of discharge have been investigated for condition of spark in a multiple spark ignition engine, as the spark duration, capacitive and inductive discharge energy were calculated for condition of spark by ignition wave and energy formula. The useful portion of spark discharge is divided into capacitance portion and inductance portion. It was found that capacitive discharge energy and spark duration were increased according to increasing number of spark, and inductive discharge energy was increased according to increasing spark interval. Therefore engine torque was increase and lean misfire limit was extended comparing with the standard ignition system. It found that spark energy was discharged within ignition delay period availability acted on the formation and growth of flame kernel, and total spark energy was increased according to increasing number of spark times, but discharged spark energy after ignition delay became unavailable energy. And the capacitive discharge energy has the dominant effect for stoichiomeric or not very rich air-fuel mixture but inductive discharge energy has the dominant effect for lean air-fuel mixture.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.7
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• pp.666-674
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• 2001

Classical methods to find a minimal set of rules based on the rough set theory are known to be ineffective in dealing with new instances added to the universe. This paper introduces an inductive learning algorithm for incrementally retrieving a minimal set of rules from a given decision table. Then, the algorithm is validated via simulations with two sets of data, in comparison with a classical non-incremental algorithm. The simulation results show that the proposed algorithm is effective in dealing with new instances, especially in practical use.