• Journal of Power Electronics
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• v.18 no.2
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• pp.573-587
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• 2018

Recently evolved power electronics' based domestic/residential appliances have begun to behave as single phase non-linear loads. Performing as voltage/current harmonic sources, those loads when connected to a three phase distribution network contaminate the line current with harmonics in addition to creating a neutral wire current increase. In this paper, an enhanced performance three phase four leg shunt active power filter (SAPF) controller is presented as a solution for this problem. The presented control strategy incorporates a hybrid predictive fuzzy-logic based technique. The predictive part is responsible for the SAPF compensating current generation while the DC-link voltage control is performed by a fuzzy logic technique. Simulations at various loading conditions are carried out to validate the effectiveness of the proposed technique. In addition, an experimental test rig is implemented for practical validation of the of the enhanced performance of the proposed technique.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.4
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• pp.167-174
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• 2003

This paper proposes a network processor especially optimized for content switching. With 2Gbps port capability, it integrates packet processor cluster, content-based classification engine and traffic manager on a single chip. A switch fabric architecture is also designed for scale-up of the network processor's capability over hundreds gigabit bandwidth. Applied in real network systems, the network processor shows wire-speed network address translator (NAT) and content-based switching performance.

• Transactions on Electrical and Electronic Materials
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• v.16 no.1
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• pp.37-41
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• 2015

The most common structure of the current transformer (CT) consists of a length of wire wrapped many times around a silicon steel ring passed over the circuit being measured. Therefore, the primary circuit of CT consists of a single turn of the conductor, with a secondary circuit of many tens or hundreds of turns. The primary winding may be a permanent part of the current transformer, with a heavy copper bar to carry the current through the magnetic core. However, when the large current flows into a wire, it is difficult to measure its magnitude of current because the core is saturated and the core shows magnetic nonlinear characteristics. Therefore, we proposed a newly designed CT which has an air gap in the core to decrease the generated magnetic flux. Adding the air gap in the magnetic path increases the total magnetic reluctance against the same magnetic motive force (MMF). Using a ferrite core instead of steel also causes the generation of low magnetic flux. These features can protect the magnetic saturation of the CT core compared with the steel core. This technique can help the design of the CT to obtain a special shape and size.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2003.04a
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• pp.164-170
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• 2003

In this paper, we studied on the firing characteristics and electrical fire analysis of power cord deteriorated by thermal stress. The cross section of PVC insulating cord deteriorated by indirect flame decreased through heat convection. PVC insulating cord deteriorated by direct flame was bumpy shape. The exothermic peak of normal cord was shown at ($526.7^{\circ}C$), but the peaks or on(heat treatment temperature) ($150^{\circ}C$) cord was shown at ($299.6^{\circ}C$) and [$502.2^{\circ}C$]. The exothermic peaks according to high temperature were similar to those of amorphous carbon. In the FT-IR analysis, the absorption peak of normal cord indicated double bond of oxygen and carbon in benzene ring at 1720.0$cm^{1}$. As the HTT was high, the height of characteristic peak decreased and the peak of carbonyl group was shown at about 1625.7$cm^{-1}$. The characteristic peak of single bond(O-H) was shown at about 3479.2$cm^{-1}$. In case of the internal part of wire covering deteriorated by over current, the characteristic peak were shown at about 3417.3$cm^{-1}$ and 1600.2$cm^{-1}$. The above results show that we can distinguish the differences according to the fire pattern through the internalㆍexternal analysis of wire covering deteriorated by heat.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.329-338
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• 2001

In this paper, we designed microstrip patch antenna to enhance the weak point of general microstrip patch antenna that has narrow bandwidth and analyzed that. To reduce reactance in probe feed antenna, capacitive gap added to the patch. Using single patch and auxiliary wire, makes dual frequency resonant. So bandwidth is improved and gain also becomes higher. To verify with experiment, PCS band antenna is designed, fabricated. For PCS band antenna, bandwidth is 180 MHz in VSWR<1.5 and gain is 8.6 dBi.

• Journal of Powder Materials
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• v.17 no.6
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• pp.464-469
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• 2010

The Cu nanofluid in ethylene glycol was prepared by electrical explosion of wire, a novel one-step method. The X-ray diffraction, field emission scanning electron microscope and transmission electron microscope were used to study the properties of Cu nanoparticles. The results showed that the nanoparticles were consisted of pure face-centered cubic structure and near spherical shape with average grain size of 65 nm. Ultraviolet-visible spectroscopy (UV-Vis) confirmed Cu nanoparticles with a single absorbance peak of Cu surface plasmon resonance band at 600 nm. The nanofluid was found to be stable due to high positive zeta potential value, +51 mV. The backscattering level of nanofluid in static stationary was decreased about 2% for 5 days. The thermal conductivity measurement showed that Cu-ethylene glycol nanofluid with low concentration of nanoparticles had higher thermal conductivity than based fluid. The enhancement of thermal conductivity of nanofluid at a volume fraction of 0.1% was approximately 5.2%.

• Journal of Information Display
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• v.12 no.3
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• pp.115-119
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• 2011

Optically isotropic liquid crystal (LC) mixture such as blue-phase LC and nanostructured LC composites exhibit the advantages of fast response time, high contrast ratio and wide-viewing angle due to the induced birefringence along the horizontal electric field. Utilizing this mixture, a novel single cell gap in-plane switching-type polymer-stabilized blue-phase transflective liquid crystal display by embedding the nanowire grid polarizer as a polarization-dependent reflective polarizer in the R region is proposed. This device can be used as a normal black mode without any quarter-wave plate or patterned in-cell phase retarder. Moreover, the transmittance is identical to the reflectance so that it will be suitable for single gamma driving. Detailed electro-optic performances, such as voltage-dependent light efficiency and viewing angle of the proposed device configuration, are investigated.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.1
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• pp.27-38
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• 2017

Packet classification is one of the essential functionalities of Internet routers in providing quality of service. Since the arrival rate of input packets can be tens-of-millions per second, wire-speed packet classification has become one of the most challenging tasks. While traditional packet classification only reports a single matching result, new network applications require multiple matching results. Ternary content-addressable memory (TCAM) has been adopted to solve the multi-match classification problem due to its ability to perform fast parallel matching. However, TCAM has a fundamental issue: high power dissipation. Since TCAM is designed for a single match, the applicability of TCAM to multi-match classification is limited. In this paper, we propose a cost- and energy-efficient multi-match classification architecture that combines TCAM with a tuple space search algorithm. The proposed solution uses two small TCAM modules and requires a single-cycle TCAM lookup, two SRAM accesses, and several Bloom filter query cycles for multi-match classifications.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.251-255
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• 2015

In this paper, we propose a fuse controller which is used for storing the optimal value or the correction value for the surrounding product of the IoT applications and it is implemented serial communication circuit using a single pin. Because of the proposed single pin protocol is simpler in the hardware than the conventional $I^2C$ and SPI using two or more pins, it is suitable for the area of small amount of data transmission. The function of the one pin protocol is verified by logic simulation and the FPGA test board and it is fabricated using CMOS 0.35um technology. It is expected to use the IoT product that require the low power consumption and simple hardware.

• Journal of the Korean Magnetics Society
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• v.2 no.2
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• pp.150-155
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• 1992

The low magnetic field standard below 1 mT with resolution of 100 nT has been established for the calibration and testing of low field magnetometers. A precision single layered solenoid, which is made of quartz tube and bare copper wire, was constructed in order to generate a precise magnetic field. To improve the field homogeneity in the solenoid, three-current method was employed. The injected current and injection points on the solenoid were optimized by computer simulation. The magnetic field uncertainty in the solenoid was 0.1 % and 0.01 % in the range of ${\pm}5\;cm$ from the center for a single and three-current methods respectively. We also constructed a testing system for the dynamic properties of low field magnetometers.