• Bulletin of the Korean Chemical Society
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• v.9 no.4
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• pp.198-202
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• 1988

Several new palladium(II) complexes of aminophosphines, $(Pd(L)X_2)$, (L = $Ph_2PNH$ ++ $NR_2$; R = $CH_3(L_1)$, $C_2H_5(L_2)$ : X = Cl, Br, I, and NCS) that contain two different donor atoms of nitrogen and phosphorus as ${\pi}$-electron acceptor, were synthesized and characterized by conductivity measurement, ir, and UV/Vis-spectra. For the dithiocyanatopalladium(II) complexes with aminophosphines, it was confirmed that the thiocyanate group trans to phosphorus is coordinated as Pd-NCS mode and the one trans to nitrogen as Pd-SCN mode, and the aminophosphines form six-membered chelate ring. The spectra of dihalogenopalladium(II) complexes with aminophosphines show that the band maxima are shifted to the short wavelengths as the concentration is decreased.

• Transactions of the Korean hydrogen and new energy society
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• v.12 no.3
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• pp.231-238
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• 2001

Electrocatalytic activity of palladium for hydrogen oxidation and reduction was studied using AC impedance method. The system under study was arranged in electrolytic mode consisting of Pd electrode under study, Pt counter electrode and Nafion electrolyte between them. Two types of Pd electrodes were used - carbon-supported Pd (Pd/C) and Pd foil electrode. Pd/C anode contacting pure hydrogen showed a steady decrease of charge transfer resistance with the increase of anodic overpotential, which is an opposite trend to that found with Pd foil anode. But Pd foil cathode also exhibited a decrease of the resistance with the increase of cathodic overpotential. The relationship between imposition of overpotential and subsequent change of the charge transfer resistance is determined by the ratio of the rate of faradaic process to the rate of mass transportation; if mass transfer limitation holds, increase of overpotential accompanies the increase of charge transfer resistance. Regardless of the physical type of Pd electrode, the anode contacting hydrogen/oxygen gas mixture did not reveal any independent arc originated from local anodic oxygen reduction.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2369-2376
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• 2007

N2O has been found from experimental and theoretical considerations to bind on-top to the Pd(110) surface in a tilted end-on fashion via its terminal N atom. We use a frontier orbital description of the bonding interactions in the Pd-N2O system to obtain molecular insight into the catalytic mechanism of the activation of N2O by the Pd(110) surface giving rise to the formation of N2 and O on the surface. For the tilted end-on N2O binding mode, the LUMO 3π of N2O has good overlap with the Pd dσ and dπ orbitals which can serve as the electron donors. The donor-acceptor orbital overlap is favorable for electron transfer from Pd to N2O and is expected to dominate the surface reaction pathway of N2O decomposition.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.842-846
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• 1997

Micro-hole drilling (holes less than 0.5 mm in diameter with aspect ratios larger than 10) is gaining increased attention in a wide spectrum of precision production industries. Alternative methods such as EDM, laser drilling, etc. can sometimes replace mechanical micro-hole drilling but are not acceptable in PCB manufacture because they yield inferior hole quality and accuracy. The major difficulties in micro-hold drilling are related to wandering motions during the inlet stage, high aspect ratios, high temperature,etc. However, of all the difficulties, the most undesirable one is the increase of drilling force as the drill penetrates deeper into hold. This is caused mainly by chip related effects. Peck-drilling is thus widely used for deep hole drilling despite the fact that it leads to low productivity. Therefore, in this paper, a method of cutting force regulation is proposed to achieve continuous drilling. A proportional plus derivative (PD) and a sliding modecontrol algorithm will be implemented for controlling the spinle rotational frequeency. Experimental results will show that sliding mode control reduces the nominal cutting force and its variation better than the PD control, resulting in a number of advantages such as an increase in drill life, fast stabilization of the wandering motion, and precise positioning of the hole.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.199-202
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• 2008

본 논문은 Fuzzy Slide Mode Control 및 BLDC모터를 이용하여 공기의 부하를 모사한 Actuator System에 관한 연구이다. 모터를 제어하기 위한 알고리즘으로 PID, PD, fuzzy Slide Mode Control의 특징을 비교 분석하였고 외란의 영향에 강한 Fuzzy Slide Mode Control을 적용하였다. 모터의 토크를 제어하여 실제 공기 부하에 맞는 토크를 모사함으로써 최대 2.3Nm의 토크와 50Hz의 응답 특성을 얻었다.

• Journal of Korea Multimedia Society
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• v.18 no.11
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• pp.1289-1301
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• 2015

Pedestrian detection (PD) is an essential task in various applications and sliding window-based methods utilizing HOG (Histogram of Oriented Gradients) or HOG-like descriptors have been shown to be very effective for accurate PD. However, due to exhaustive search across images, PD methods based on sliding window usually require heavy computational time. In this paper, we propose a real-time PD method for embedded visual surveillance with fixed backgrounds. The proposed PD method employs HOG descriptors as many PD methods does, but utilizes selective search so that it can save processing time significantly. The proposed selective search is guided by restricting searching to candidate regions extracted from Adaptive Gaussian Mixture Model (AGMM)-based background subtraction technique. Moreover, approximate computation of HOG descriptor and implementation in fixed-point arithmetic mode contributes to reduction of processing time further. Possible accuracy degradation due to approximate computation is compensated by applying an appropriate one among three offline trained SVM classifiers according to sizes of candidate regions. The experimental results show that the proposed PD method significantly improves processing speed without noticeable accuracy degradation compared to the original HOG-based PD and HOG with cascade SVM so that it is a suitable real-time PD implementation for embedded surveillance systems.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.5
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• pp.554-562
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• 2015

This paper describes an analysis of an architecture and control system of a firefighting cannon manipulator (FCM) composed of two joint axes and one water-shooting actuator. Because the orienting FCM motion is disturbed by the reaction force from water shooting, the water shooting force has been modeled for robust control. The dynamics model of the manipulator has been set up including the external force of water-shooting reaction on the manipulator. A PD Controller and Sliding Mode Controller have been designed and their performance been tested through simulation to track a desired trajectory under the disturbance of a water-shooting reaction. The simulation shows that the performance of the Sliding Mode Controller is better than that of the PD controller.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2184-2188
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• 2007

We developed a novel method of partial discharge(PD) location based on the fact that the waveform of PD signal propagate along the GIB (Gas Insulated Bus) is composed of several modes of electromagnetic wave with different group velocities and cut-off frequencies. From the PD waveform, measured at a broadband PD sensor attached on the GIB, we could derive arrival time and frequency components of different modes using the short term Fourier transform or etc. After the group velocities of different modes are calculated, the location of the PD source could be estimated. To show the effectiveness of this new locating method in a real on site application, we used this method to locate the position of a PD source at a 76 m long 345 kV GIB substation. The estimated location of the PD source using the method proposed above was in good agreement with the actual location found from the inspection result of internal component in the GIB with 2.4% of the estimation error.

• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.2
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• pp.6-11
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• 2001

Abstract- In this paper, a new Partial Discharge (PD) detection using Pockels cell was proposed and considerable apparent chaotic characteristics were discussed. For this purpose, PD was generated from needle-plane electrode in air and detecte by optical measuring system using Pockels cell, based on Mach-Zehner interferometer, consisting of He-Ne laser, single mode optical fiber, 50/50 beam splitter and photo detector. In addition, the presence of chaos of the PD signals has been investigated by examining their means of qualitative and quantitative information. For the former, return map and 3-dimensional strange attractor have been drawn in order to investigate the presence of chaotic characteristics relevant to PD signals, detected through CT and Peckels sensor respectively, in the normalized time series. The presence of strange attractor indicates the existence of fractal structures in it's phase space. For the latter, several dimension values of strange attractor were verified sequentially. Throughout this paper, it is likely that the chaotic characteristics regarding the PD signals under air are verified.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1850-1852
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• 2000

In this paper, new Partial Discharge (PD) detection technique using Pockels cell was proposed and considerable apparent chaotic characteristics were discussed. For this purpose, PD was generated from needle-plane electrode in air and detected by optical measuring system using Pockels cell, based on Mach-Zehnder interferometer, consisting of He-Ne laser, single mode optical fiber, 50/50 beam splitter and photo detector. A qualitative analysis was carried out by drawing Return map for the normalized time series of the detected PD signals. The results are as follows:(a) Fixed points, between 0.7 and 1.0, are appeared clearly in the right upper area of the return map as the increase in the number of obtained data.(b) Considerable periodicity have been remarked even though exact period and length can not be determined.(c) The self-similarity can be also observed inasmuch as the late paths do not follow the previous ones. Accordingly, exact quantitative analysis such as embedding dimension, fractal dimension, and Lyapunov exponents should be carried out for deducing the quantitative properties regarding PD phenomena.