• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.5
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• pp.576-584
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• 2014

In this paper, a study on the optimization of fuzzy classifier using radar cross section(RCS) values is presented to classify shell-shaped targets. Method of moments(MOM) is exploited to construct RCS database of generic shell-shaped targets in uniform angular intervals. Relative orientations are estimated from various flight scenarios of shell-shaped targets, and associated RCS values are interpolated from the generated RCS database with uniform angular intervals. Initial membership functions are determined using the interpolated RCS values, and particle swarm optimization(PSO) is utilized to optimize the membership functions of the fuzzy classifier in terms of probability of correct classification.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11C
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• pp.694-701
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• 2011

This paper addresses a synchronization technique based on an adaptive combining of the sub-correlation functions obtained from multiband sine phased binary offset carrier (BOC) signals, allowing a BOC signal receiver to deal with multiband sine phased BOC signals. Specifically, we first obtain the sub-correlation functions composing the BOC autocorrelation function, and then, re-combine the sub-correlation functions generating a correlation function with no side-peak. Finally, by replacing the BOC autocorrelation with the correlation function with no side-peak in the delay lock loop, the proposed scheme performs unambiguous signal tracking. The proposed synchronization scheme is applicable to generic sine phased BOC signals. Numerical results demonstrate that the proposed scheme provides a performance improvement over the conventional unambiguous schemes in terms of the tracking error standard deviation.

• Journal of Korean Academy of Nursing
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• v.44 no.1
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• pp.55-63
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• 2014

Purpose: This study was conducted to examine the late effects, social adjustment, and quality of life in adolescents who had been completely treated for childhood leukemia and their parents. Methods: Participants consisted of 41 pairs of adolescent survivors (13-18 years) and their parents. Parents checked for their child's physical late effects. The Korean Version of Post-Traumatic Symptoms for psychological late effects, social functioning questionnaire for social adjustment and the PedsQL 4.0 Generic Core Scales for quality of life were completed by adolescents and parents. Data were analyzed using SPSS. Results: Twenty out of 41 adolescents had one or more physical late effects. Adolescents showed more serious psychological late effect than parents. Five children and seven parents had above cut-off scores and they were considered the high risk group for posttraumatic symptoms. Parent-reported scores were significantly higher than child-reported scores in terms of social adjustment and emotional functioning of quality of life. Low school functioning in adolescents was associated with physical late effects. Conclusion: The results indicate that long-term and systematic management for childhood leukemia survivors affect positive social adjustment and can further improve quality of life.

• Journal of Educational Research in Mathematics
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• v.16 no.1
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• pp.79-94
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• 2006

The purpose of this study is to find out the characteristics of the types(levels) of justification which are appeared by elementary mathematically gifted students in solving the tasks of plane division and spatial division. Selecting 10 fifth or sixth graders from 3 different groups in terms of mathematical capability and letting them generalize and justify some patterns. This study analyzed their responses and identified their differences in justification strategy. This study shows that mathematically gifted students apply different types of justification, such as inductive, generic or formal justification. Upper and lower groups lie in the different justification types(levels). And mathematically gifted children, especially in the upper group, have the strong desire to justify the rules which they discover, requiring a deductive thinking by themselves. They try to think both deductively and logically, and consider this kind of thought very significant.

• Journal of Korean Society of Transportation
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• v.28 no.6
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• pp.75-84
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• 2010

Controlled traffic intersection is critical point in terms of transportation network performance, where the most of traffic congestion arises. One of the most important and favorable measure of effectiveness in the signal controlled intersection is approach delay. Although lots of efforts to develop traffic delay estimation models have been made throughout the years, most of them were focusing on homogeneous traffic flow. The purpose of this research is to develop a traffic delay estimation model for traffic flow mixed with bus based on the horizontal shockwave theory. Traffic simulation is performed to test the adaptation level of the model in generic environment. The result shows that the delay increases with increasing bus traffic. Overall model accuracy comparing simulation result is acceptable, that shows the error range around 10 percent.

• Journal of Biomedical Engineering Research
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• v.36 no.5
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• pp.169-176
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• 2015

Implantable closed-loop epilepsy controllers require ideally both accurate epileptic seizure detection and low power consumption. On-chip oscillators can be used in implantable devices because they consume less power than other oscillators such as crystal oscillators. In this study, we investigated the tolerable error range of a lower power on-chip oscillator without losing the accuracy of seizure detection. We used 24 ictal and 14 interictal intracranial electroencephalographic segments recorded from epilepsy surgery patients. The performance variations with respect to oscillator frequency errors were estimated in terms of specificity, modified sensitivity, and detection timing difference of seizure onset using Generic Osorio Frei Algorithm. The frequency errors of on-chip oscillators were set at ${\pm}10%$ as the worst case. Our results showed that an oscillator error of ${\pm}10%$ affected both specificity and modified sensitivity by less than 3%. In addition, seizure onsets were detected with errors earlier or later than without errors and the average detection timing difference varied within less than 0.5 s range. The results suggest that on-chip oscillators could be useful for low-power implantable devices without error compensation circuitry requiring significant additional power. These findings could help the design of closed-loop systems with a seizure detector and automated stimulators for intractable epilepsy patients.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12C
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• pp.1142-1148
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• 2007

In this paper, we propose ASLM (Adaptive Selective Mapping; ASLM) scheme based on peak observation for PAPR (Peak-to-Average Power Ratio) reduction of OFDM (Orthogonal Frequency Division Multiplexing) signals. The proposed scheme is composed of three steps: peak scaling, sequence selection, and SLM procedures. In the first step, the peak signal samples in the IFFT (Inverse Fast Fourier Transform) outputs of the original input sequence are scaled down. In the second step, the sub-carrier positions where the power difference between the original input sequence and the FFT output of the scaled signal is large, are identified. Then, the phase sequences having the maximum number of phase-reversed sequence words only for these positions are selected. Finally, the generic SLM procedure is performed by using only the selected phase sequences for the original input sequence. Simulation results show that the proposed scheme significantly reduces the complexity in terms of IFFT and PAPR calculation than the conventional SLM, while maintaining the PAPR reduction performance.

• Korean Journal of Plant Taxonomy
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• v.41 no.2
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• pp.108-112
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• 2011

The pollen of 5 taxa on Korean Oldenlandia L. was investigated by LM and SEM. The pollen grains were monads, $20.7-36.0{\mu}$m in polar length, with an equatorial diameter of $21.0-38.4{\mu}m$. The pollen shapes were oblate-spheroidal or spherical (P/E ratio 0.93-1.00). The apertures numbered 3-7 in number, colporate in shape, with a colpus length of $4.2-20.4{\mu}m$ and a colpus width of $2.6-3.4{\mu}m$. The sexine was $0.9-2.4{\mu}m$ in terms of its thickness, the surface pattern was reticulate, scabrate or neither. Based on these results, the size of the pollen grain, the number of apertures, and the surface pattern of the sexine were all useful for an interspecific classification. The genus Neanotis, established via the pollen characteristics, was thought to be reviewed in its entity regarding the continuous variation of generic characteristics.

• Journal of Distribution Science
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• v.15 no.6
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• pp.47-56
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• 2017

Purpose - The purpose of this study is to examine the viability of imitation strategy. Imitation strategy is one of the strategic options that a late mover can choose, and by selecting the strategy, the company imitates key elements of the business model of first movers, and modifies them to suit its conditions. The author attempted to explain how the elements of first mover's business models were creatively adapted to suit the conditions of late movers so that they can secure market position face-to-face market leaders. Research design, data, and methodology - For the purpose of the study, Korean coffee franchise industry was selected to compare the strategies of first and late movers and to discuss imitation strategy in detail. The author conducted in-depth case study of first mover and business model innovator Starbucks and Ediya Coffee, one of their imitators. The paper examines how Ediya has imitated and modified the business model of Starbucks to secure its unique competitive position in domestic market by using value chain and generic strategy analysis. Results - Starbucks and Ediya were compared in terms of their interior design, the price level of beverages, the variety of side dishes, and shop locations. Starbucks have invested interior design heavily to shops, offered diverse beverages and side dishes with relatively high price, the shops are located in central areas, whereas Ediya has concentrated on achieving cost leadership in all value activities as maintaining the quality of key products. Ediya succeeded in achieving best-provider strategy, in which it enjoys both cost leadership and differentiation advantages, largely by the strategic alliance with the biggest coffee manufacturer, Dongsuh Foods in Korea. Conclusions - Though Ediya is the imitator of Starbucks, it has modified Starbucks business models and succeeded in providing the 'third place' experience for budget-minded customers. Ediya has also succeeded in benefiting its franchisees by lowering costs and simplifying the various tasks of coffee shop management. Due to these factors, Ediya could become one of the largest number shops as the coffee franchise in Korea.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.3
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• pp.21-32
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• 2003

This paper discusses the design of location optimization visualization and feasibility of 3 dimensional visualization techniques. In generic GIS visualization of location analysis, 2 dimensional visualization techniques have been used to map location elements and model solution, such as displaying demand and supply points, drawing connecting lines(e. g. spider line) of optimal locations to their demands, and representing density of location variations. Nevertheless, current GIS and location analysis literatures have little attentions in 3D visualization applications for location optimization problems. Previous research has been neglected 3D visualization of solution performances and its evaluation of solution quality. Consequently, this paper demonstrates potential benefits of 3D visualization techniques and its appropriate GIS applications for location optimization analysis. The visualization effectiveness of 3D approaches is examined in terms of spatial accessibility, and solution performance of optimal location models is evaluated. Finally, this paper proposes extensive 3D visualization perspectives for location analysis and GIS research as a further research agenda.