• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.835-840
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• 2011

In this study, a disk-type piezoelectric transformer was fabricated. Its diameter was 50 mm and thickness was 4.5 mm. The driving and generating electrode with their gap of 1mm were fabricated on the top surface. But the common electrode was fabricated on the whole bottom surface. The electrode surface of driving and generating part on the top surface was divided into 2, 4 and 8 pieces. The electrical characteristics with its electrode variation was measured in the range of load resistance of $100{\Omega}{\sim}10_{K\Omega}$. We investigated quantitively the influence of the set-up voltage ratio.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.157-162
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• 2006

In this paper, power supply for ozone generating system is explained. Output voltage and frequency are controlled by phase displacement control of single phase inverter using ATmega128. The values of desired output voltage and frequency set using keypad and displayed using LCD. Actually, power supply is designed and manufactured. Through the experiments, the performance of output voltage and frequency control is verified.

• Journal of Periodontal and Implant Science
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• v.34 no.3
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• pp.659-669
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• 2004

The aim of this study was to evaluate the clinical efficacy of mouthrinses prepared by sterilized water-generating $device(Purister^{(R)})$ on the control of gingivitis and incipient periodontitis when it was used as a adjunctives to the mechanical plaque control. 40 healthy patients with gingivitis or incipient periodontitis were divided into two groups. Patients in the experimental group use mouthrinses prepared by sterilized water-generating $device(Purister^{(R)})$ after tooth brushing while patients in the control group do only tooth brushing for plaque control. All patients received scaling and tooth brushing instruction. 1 week after scaling was set as baseline. Probing pocket depth, clinical attachment level, and bleeding on probing were scored at baseline, 4 weeks. Gingival index and plaque index were scored at baseline, 2 weeks, and 4 weeks. The results were as follows: 1. In the experimental group, gingival index, plaque index, probing pocket depth, and clinical attachment level showed statistically significant decrease, but in the control group, significant increase(p<0.05). 2. There was no significant difference between the experimental and the control group in bleeding on probing, but significant decrease in the experimental group and Significant increase in the control group In a time-dependent manner(p <0.05). From these results, it can be concluded that regular use of mouthrinses prepared by sterilized water-generating $device(Purister^{(R)})$ as adjunctives of mechanical plaque control, may be effective to prevent and treat gingivitis and incipient periodontitis.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.12
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• pp.675-683
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• 2003

This paper describes the correction strategy of an overcurrent relay applied in the linked line for interconnecting wind farm with utility power networks in order to improve the capability of a fault detection. The fault current measured in a relaying point might vary according to the fault conditions. Generally, the current of the line to line fault or the line to ground fault in the linked line is much higher than the set value of protective relay due to the large fault level. However, when the high impedance fault occurs in the linked line, we can't detect it by conventional set value because its fault level may be lower than the generating capacity of wind farm. And, the protective relay with conventional set value may generate a trip signal for the insertion of wind turbine generators due to the large transient characteristics. In order to solve above problems and improve protective relaying algorithms applied in the linked line, we propose a new correction strategy of the protective relay in the linked line. The presented method can detect the high impedance fault which can't be detected by conventional relay set value and may prevent the mis-operation of protective relay caused by the insertion of wind farm.

• Journal of the Korean Statistical Society
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• v.10
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• pp.97-104
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• 1981

It is shown that a lattice distribution defined on a set of n lattice points $L(n,\delta) = {\delta,\delta+1,...,\delta+n-1}$ is a distribution induced from the distribution of convolution of independently and identically distributed (i.i.d.) uniform [0,1] random variables. Also the m-th moment of the lattice distribution is obtained in a quite different approach from Park and Chung (1978). It is verified that the distribution of the sum of n i.i.d. uniform [0,1] random variables is completely determined by the lattice distribution on $L(n,\delta)$ and the uniform distribution on [0,1]. The factorial mement generating function, factorial moments, and moments are also obtained.

• Bulletin of the Korean Mathematical Society
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• v.41 no.3
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• pp.521-540
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• 2004

In this paper, we give a sharp estimate on the cardinality of the set generating the convex hull containing the image of harmonic maps with polynomial growth rate on a certain class of manifolds into a Cartan-Hadamard manifold with sectional curvature bounded by two negative constants. We also describe the asymptotic behavior of harmonic maps on a complete Riemannian manifold into a regular ball in terms of massive subsets, in the case when the space of bounded harmonic functions on the manifold is finite dimensional.

• ETRI Journal
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• v.19 no.4
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• pp.389-401
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• 1997

In this paper, we consider the relationship between nonlinearity and correlation immunity of Boolean functions. In particular, we discuss the nonlinearity of correlation immune functions suggested by P. Camion et al. For the analysis of such functions, we present a simple method of generating the same set of functions, which makes it possible to construct correlation immune functions with controllable correlation immunity and nonlinearity. Also, we find a bound for the correlation immunity of functions having maximal nonlinearity.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.393-396
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• 2002

In this paper, we present a new method for generating a set of complementary sequences that can be simultaneously transmitted and yet compressed into a short pulse on reveive, and its application to ultrasound imaging. This new complementary sequences can be designed based on a filter bank theory. The new complementary sequences can be used to improve the SNR of ultrasound imaging without sacrificing the spatial resolution and frame rate, compared to conventional pulse-echo imaging. Computer simulations are performed to verify the proposed method.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.648-650
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• 1998

This paper proposes a constructive algorithm for generating the Takagi-Sugeno type fuzzy model through the sequential learning from training data set. The proposed algorithm has a two-stage learning scheme that performs both structure and parameter learning simultaneously. The structure learning constructs fuzzy model using two growth criteria to assign new fuzzy rules for given observation data. The parameter learning adjusts the parameters of existing fuzzy rules using the LMS rule. To evaluate the performance of the proposed fuzzy modeling approach, well-known benchmark is used in simulation and compares it with other modeling approaches.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.444-453
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• 1997

This paper presents the prototype design of hardware/software cosynthesis system for pipelined application-specific instruction processors. Taking application programs in VHDL as inputs, the proposed system generates a pipelined instruction-set processor and the instruction sequences running on the generated machine. The design space of datapath and controller is defined by the architectural templates embedded in the system. Generating the intyermediate code adequate for parallelism analysis and extraction, the system converts it into assembly codes. Experimental results show the effectiveness of the proposed system.