• Communications for Statistical Applications and Methods
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• v.24 no.2
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• pp.163-172
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• 2017

Economic sentiment is typically measured using ordinary response options. The University of Michigan and the United States Conference Board are two widely used major indexes that have separately established independent consumer sentiment indexes based on three-level ordinary response options: positive, neutral, and negative. Notwithstanding, limited attention has been paid to the structural differences in their built-in formulas, which are referred to the disparate micro scoring schemes applied to an individual question. This paper examines the structural difference of the two indexes and then addresses situations where one is more reliable than the other. Real data from business tendency surveys of the Organization for Economic Cooperation and Development are used to illustrate our points empirically. As a conclusion, it is stressed that the two indexes should be handled with care when applied to economic sentiment comparison studies.

• Journal of Power Electronics
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• v.13 no.1
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• pp.86-93
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• 2013

A half-cycle-waveform inversion based three reference modulations seven-level SPWM (TRM-SPWM) scheme with one carrier is proposed in this paper. To keep the same comparison logics for the modulations and carrier during the negative half cycle and the positive one for the modulations, in the negative half cycle of the modulations, the DC offsets related to the amplitude of the carrier are set on the three modulations, respectively. The seven-level SPWM waveform with dead time thereby is implemented with only one Digital Signal Processor (DSP) without any other attached logic circuit. The basis principle of the proposed TRM-SPWM is analyzed in detail, and the frequency spectrums of the conventional and the proposed schemes are derived and compared with each other through simulation. The DSP based implementation is presented and detailed experimental waveforms verify the accuracy and feasibility of the proposed TRM-SPWM scheme.

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.45-51
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• 2001

The daily inflow is apparently one of nonlinear and complicated phenomena. The nonlinear and complexity make it difficult to model the prediction of daily flow, but attractive to try the neural networks approach which contains inherently nonlinear schemes. The study focuses on developing the forecasting models of daily inflows to a large dam site using neural networks. In order to reduce the error caused by high or low outliers, the back propagation algorithm which is one of neural network structures is modified by combining a regression algorithm. The study indicates that continuous forecasting of a reservoir inflow in real time is possible through the use of modified neural network models. The positive effect of the modification using tole regression scheme in BP algorithm is showed in the low and high ends of inflows.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.355-363
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• 2018

There are serious issues with the application of surfactant flooding as a third recovery method, such as surfactant slug losses. In this study,the impact of the salinity gradient on the remobilization of oiltrapped in Berea sandstone was investigated by emphasizing the surfactant adsorption gradient and phase behavior to determine the optimal salinity of the chosen surfactant concentration for investigating the salinity gradient. Three salinity-gradient schemes were applied to six cores saturated with light and heavy oils. The positive salinity gradient provided the best recovery results with an in situ microemulsion formation that could be observed in the fluid collector.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.87-89
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• 2018

We proposed an improved reliable SVD-based watermarking scheme resistant to geometric attacks while having high fidelity with no false-positive problem. Principal components of a watermark image are embedded into singular values of LL, LH, HL, and HH sub-bands of a transformed cover image by RDWT(redundant discrete wavelet transform) with optimal scale factors. Each scale factor is generated by trading-off fidelity and robustness using Differential Evolution (DE) algorithm. Zernike Moment (ZM) is used to estimate the geometric distortion and to correct the watermarked image before extracting watermark. The proposed scheme improves fidelity and robustness of existing reliable SVD based watermarking schemes while resisting to geometric attacks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.3
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• pp.938-957
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• 2023

The limited computing power of sensor nodes in wireless sensor networks (WSNs) and data tampering during wireless transmission are two important issues. In this paper, we propose a scheme for independent individual authentication of WSNs data based on digital watermarking technology. Digital watermarking suits well for WSNs, owing to its lower computational cost. The proposed scheme uses independent individual to generate a digital watermark and embeds the watermark in current data item. Moreover, a sink node extracts the watermark in single data and compares it with the generated watermark, thereby achieving integrity verification of data. Inherently, individual validation differs from the grouping-level validation, and avoids the lack of grouping robustness. The improved performance of individual integrity verification based on proposed scheme is validated through experimental analysis. Lastly, compared to other state-of-the-art schemes, our proposed scheme significantly reduces the false negative rate by an average of 5%, the false positive rate by an average of 80% of data verification, and increases the correct verification rate by 50% on average.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.1 s.108
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• pp.81-92
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• 2005

In study, various notions regarding historic landscapes and rehabilitation were first investigated, and efficient rehabilitation schemes on modem historic landscapes were analyzed. On the basis of these theological analyses, an underlying scheme on the rehabilitation of modern historic landscapes was drawn up for '40 Stair Cultural Street' in Jung-gu, Busan City. Rehabilitating historic landscapes not only expresses a positive method to preserving sites and relics of heritage, but also an idea of preservation and rehabilitation based on interpretations from a historical perspective of value in this present day. Its significance is, therefore, to construct an ideal urban landscape in which the past, present and future can coexist. The rehabilitation of historic landscapes will become a psychological pillar to the people living in cities and will be able to lead the various types of urban activities as effective landmarks creating accessibility and representing perpetuity, as rehabilitated landscapes last through the passage of time. In addition, since historic and cultural landscape resources significantly represent regional identities and cultural characteristics that are protected and maintained, they may result in the succession of time and space in regional and urban historical culture and contribute to improving local images and impressions, allowing citizens and tourists to experience many diverse historic and cultural environments. The underlying scheme on the development of '40 Stair Cultural Street' in the study has been drawn up with a focus on the rehabilitation of modern historic value drawn out of the 40 stairs. The area around the 40 stairs, which was shaped as a stronghold of refugees who fled for safety during the Korean War, has changed as dramatically as people can no longer get a feel of the circumstances of that period. Local historians and residents, however, still share the joys and sorrows of refugee life as sad memories. Based on the historical fact, landscape planting, street furniture, outdoor color schemes & signage, traffic systems, symbolic 3-D models and pavement designs are underway.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.1
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• pp.55-63
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• 2006

Recently, there is much abnormal traffic driven by several worms, such as Nimda, Code Red, SQL Stammer, and so on, making badly severe damage to networks. Meanwhile, diverse prevention schemes for defeating abnormal traffic have been studied in the academic and commercial worlds. In this paper, we present the structure of a stepwise intrusion prevention system that is designed with the feature of putting limitation on the network bandwidth of each network traffic and dropping abnormal traffic, and then compare the proposed scheme with a pre-existing scheme, which is a True/False based an anomaly prevention scheme for several worm-patterns. There are two criteria for comparison of the schemes, which are Normal Traffic Rate (NTR) and False Positive Rate (FPR). Assuming that the abnormal traffic rate of a specific network is $\beta$ during a predefined time window, it is known that the average NTR of our stepwise intrusion prevention scheme increases by the factor of (1+$\beta$)/2 than that of True/False based anomaly prevention scheme and the average FPR of our scheme decrease by the factor of (1+$\beta$)/2.

• Korean Journal of Microbiology
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• v.27 no.4
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• pp.404-414
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• 1989

Attempts were made to isolate and identify Gram-positive or lactic acid bacteria in Kimchi fermentation. Species diversity depended on isolation media and temperatures, and diversity tended to be reduced with decrease of temperature. MRS and KM (natural medium prepared from Kimchi materials) were suitable respectively for isolation and present number of species. Identification of isolates was performed by dichotomous identification schemes arranged on the basis of Bergey's manual of Systematic Bacteriology (1986). Gram-positive bacteria isolated at different temperatures (5, 15, $25^{\circ}C$) were 5 species of Leuconostoc, 4 species of Streptococcus, 3 species of Pediococcus, 2 species of Bacillus and 18 species of Lactobacillus. Species with high frequency of appearance were Lactobacillus plantarum, Streptococcus raffinolactis, Leuconostoc mesenteroides subsp. mesenteroides at $25^{\circ}C$, L. plantarum, Lactobacillus fructosus, L. mesenteroides subsp. mesenteroides at $15^{\circ}C$ and L. mesenteroides subsp. mesenteroides, Leuconosotoc paramesenteroides, Lactobacillus maltaromicus at $15^{\circ}C$. In general, Kimchi fermentation was achieved by Lactobacillus spp. (59.7% frequency) at $25^{\circ}C$ and Leuconostoc spp. (65.2% frequency) at $5^{\circ}C$. Pediococcus cerevisiae and Streptococcus faecalis which have been so far known as bacteria of Kimchi fermentation were not isolated.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1326-1333
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• 2016

It is important to clear the fault and prevent resulting in damage to power system. Although the frequency of generator internal fault is relatively low, it can lead to incalculable damage to power system as well as generator. Especially, loss of field on generator can cause the generator to lose synchronism for a short time if it is not removed promptly. Therefore, it is needed to conduct research on loss of field relay for detecting or clearing the loss of field. However, the setting of the relay may vary in generator operator or engineer, and the relay is not coordinated well with other elements associated with loss of field. In this paper, we address specifically the coordination of positive offset mho loss of field relay which is one of the protection schemes for loss of field. Computer simulations are performed by using ElectroMagnetic Transients Program-Restructured Version (EMTP-RV) based on actual data.