• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.3-12
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• 2016

Recently, the study on 5G mobile communication systems using the millimeter-wave frequency band have been actively promoted and the importance of compensation of the nonlinearity of power amplifier caused by the characteristics of millimeter-wave frequency propagation attenuation is increasing. In the paper, we propose a piecewise polynomial model based on subdivision coefficient which are characteristics of power amplifier separated linear section and a non-linear section. In addition, the structure of digital predistortion based on the proposed model and direct learning method are proposed to implement a digital predistortion. To verify the proposed model, digital predistortion based on the proposed model and direct learning method for 60 GHz power amplifier using LTE signal implemented in the FPGA. And the hardware test bench measured performance and complexity. The proposed model achieves 3.3 dB gain over the single polynomial model in terms of the ACLR and reduces 7.5 percent in terms of the complexity.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.4
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• pp.13-22
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• 1999

The purpose of this research is to examine resource characteristics affecting the overall recreation suitability of natural recreation forest. On the basis of resource-based approach, we had constructed a conceptual framework for this research and found one dependent variable of the overall recreation suitability and eight independent variables, representing characteristics of recreation resource. After questionnaire surveying of 690 visitors from 10 among 72 natural recreation forests in Korea. We have analyzed the data using descriptive statistics, correlation analysis, and multiple linear regression method. We have found that 1) physical factor of recreation resources turned out to be statistically insignificant and the direction of relationship between independent variable and dependent variable is the same as that of dependent variable, 2) noise, sound and smell turned out to be the most important variable in terms of magnitude of independent variable and wild life turned out to be the next important variable, and 3) noise, sound and smell turned out to have aboutn 3.3 times greater thant that of landscape, judging from the absolute value of standardized regression coefficient. The research findings can be used for planning and designing of natural recreation forests based on recreation suitability of forest resources, and will provide pertinent guidelines for management of recreation resources of natural recreation forests. The approach and method of evaluating recreation suitability employed in this research provide us valid and reliable results and will be highly useful in other resource-based recreation development. We suggest that the differences in recreation suitability between private and public recreation forests and the relationship between user-satisfaction and recreation suitability of natural recreation forests must be examined in the future research.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.184-192
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• 2011

In this study, we introduce a identification methodology for FCM-based fuzzy model. The two underlying design mechanisms of such networks involve Fuzzy C-Means (FCM) clustering method and Particle Swarm Optimization(PSO). The proposed algorithm is based on FCM clustering method for efficient processing of data and the optimization of model was carried out using PSO. The premise part of fuzzy rules does not construct as any fixed membership functions such as triangular, gaussian, ellipsoidal because we build up the premise part of fuzzy rules using FCM. As a result, the proposed model can lead to the compact architecture of network. In this study, as the consequence part of fuzzy rules, we are able to use four types of polynomials such as simplified, linear, quadratic, modified quadratic. In addition, a Weighted Least Square Estimation to estimate the coefficients of polynomials, which are the consequent parts of fuzzy model, can decouple each fuzzy rule from the other fuzzy rules. Therefore, a local learning capability and an interpretability of the proposed fuzzy model are improved. Also, the parameters of the proposed fuzzy model such as a fuzzification coefficient of FCM clustering, the number of clusters of FCM clustering, and the polynomial type of the consequent part of fuzzy rules are adjusted using PSO. The proposed model is illustrated with the use of Automobile Miles per Gallon(MPG) and Boston housing called Machine Learning dataset. A comparative analysis reveals that the proposed FCM-based fuzzy model exhibits higher accuracy and superb predictive capability in comparison to some previous models available in the literature.

• Archives of Plastic Surgery
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• v.34 no.1
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• pp.24-36
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• 2007

Purpose: Direct anthropometry is an ideal method for preoperative planning and postoperative evaluation in plastic surgery, but it requires highly skilled specialty. Indirect anthropometry, especially photogrammetry, is an alternative method. In photogrammetry, standardized clinical photography is essential. Photogrammetry-based standardized clinical photography has several advantages over direct anthropometry. It is easier to measure and has less chance to make errors during measurement. Furthermore, it is possible to repeat measurements, and available for follow up study based on permanent custody. But, it is still different from actual measurement, and inherently less accurate than anthropometry. Methods: The authors revised the standardized clinical photography and then, carried out photogrammetry using Photoshop(Adobe, U.S.A.), and compared each data with those of anthropometry. The subjects were 50 males and 50 females, undergraduate medical students in twenties. Standard head position was obtained from the wire, fixed to cephalostat which indicates the Frankfort horizontal plane. All photographs were taken at the same situation such as fixed position of light, subject and camera, etc. Results: Total 96 measurements, based on 40 landmarks, consist of linear measurements, angular measurements and inclinations include 3 measurements in head, 22 in face, 15 in orbit, 28 in nose, 16 in lip and mouth, and 12 in ear. Conclusion: Normal photogrammetric data of face of Korean in twenties was obtained. Reliable photogrammetric measurements, not significantly different from anthropometric measurement statistically, accounted for 44 in 96 measurements(45.8%). Anthropometric values different from those of photogrammetric values were obtained by multiplying coefficient by photogrammetric value.

• Journal of Korean Society for Quality Management
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• v.47 no.2
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• pp.345-365
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• 2019

Purpose: We consider export of Korea for Muslim population of Cairo residents in Egypt. Product instant cup noodle and yuzu tea are mainly focused on Kano model and Timko's customer satisfaction factor (CS - Coefficient) analysis and conjoint analysis. Methods: Based on the evaluation and conjoint analysis, cluster analysis was additionally applied to further exploratory research as to what kind of population the target customer has. A total of 120 people, each 60 people each, were prosecuted for Muslim women, middle middle class who had over 3,000 Korean won annual income for that study, and in Cairo in August 18. Results: The Kano analysis result Instant cup noodles act as attractive elements for packaging state, cooking method, smell and convenience, and Yuzu tea acted as an attractive element of taste, eating method, raw materials, efficacy, packaging form. Customer satisfaction factor, instant cup noodles, capacity and noodle thickness was a factor of indifference in Kano analysis, but acted as an attractive factor, the way to eat citron tea was classified as a factor of indifference. Conclusion: In the case of instant cup noodles, we first set up the taste of chicken-based soup with high appreciation as a whole, a group that likes chicken-based soup taste and oil noodles for each market segment, a taste of beef based soup And popular group that likes raw noodles Appears that diversification is necessary, and it has been found that it is necessary to develop a product type by hierarchy and marketing with different size priority from group packaging container. In the case of Yuzu tea, it is indispensable to emphasize the efficacy, in particular, energy recovery preference appears high, appealing point matching the needs of energy recovery is necessary, release the citrus fruit as a product without buckwheat in Bisson Ho, the packaging container, The group that likes cups and sticks is different and we found that it is necessary to prepare all two types.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.559-569
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• 2022

Infrastructure engineering is a field that supports construction (assembly) as a representative industry that creates high added value and jobs by combining science and technology with knowledge, though its importance is underestimated. According to a report from the Ministry of Land, Infrastructure and Transport (Korea), the value-added rate (65.3%) of the engineering industry and the employment inducement coefficient (14 employees per billion won) are three times higher than in manufacturing. In particular,the forward value chain (such as project management and basic design) accounts for less than 10~15% of the total project cost but determines the overall price and quality of the infrastructure facilities. In this study, a work break-down system, design support module and database development method for road design projects for design platform development is presented. Based on the presented development method, a cloud-based infrastructure design platform's prototype is developed. The developed infrastructure engineering platform is expected to provide a web-based design work environment without time/space restrictions and greatly contribute to winning overseas business orders and securing competitiveness.

• Korean Journal of Optics and Photonics
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• v.31 no.2
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• pp.59-70
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• 2020

We discuss a modified numerical model based on the Monte Carlo radiative transfer (MCRT) method, i.e., the MCRT matrix method, for the analysis of atmospheric scattering effects in three-dimensional flash LIDAR systems. Based on the MCRT method, the radiative transfer function for a LIDAR signal is constructed in a form of a matrix, which corresponds to the characteristic response. Exploiting the superposition and convolution of the characteristic response matrices under the paraxial approximation, an extended computer simulation model of an overall flash LIDAR system is developed. The MCRT matrix method substantially reduces the number of tracking signals, which may grow excessively in the case of conventional Monte Carlo methods. Consequently, it can readily yield fast acquisition of the signal response under various scattering conditions and LIDAR-system configurations. Using the computational model based on the MCRT matrix method, we carry out numerical simulations of a three-dimensional flash LIDAR system operating under different atmospheric conditions, varying the scattering coefficient in terms of visible distance. We numerically analyze various phenomena caused by scattering effects in this system, such as degradation of the signal-to-noise ratio, glitches, and spatiotemporal spread and time delay of the LIDAR signals. The MCRT matrix method is expected to be very effective in analyzing a variety of LIDAR systems, including flash LIDAR systems for autonomous driving.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.52-59
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• 2018

To control chloride attacks which is a representative deterioration in RC(Reinforced Concrete) structures, many studies have been conducted. Above all, a method using mineral admixture was known to be effective for corrosion protection. In this study, durability test about chloride attacks was carried out for concrete specimens containing FA(Fly Ash)-representative concrete mineral admixture and OPC concrete specimens considering 3 different levels of W/B(Water to Binder). Accelerated chloride diffusion coefficient tests referred to Tang's method, total passed charge tests referred to ASTM C 1202, and compressive strength tests based on KS F 2405 were performed at each target age day. Also, based on previous studies of 28 days, time-parameter which is a key parameter for diffusion behavior is evaluated and its relations with compressive strength at the age of 365 days is evaluated. After the age of 49 days, chloride resistance of FA concrete is much improved than that of OPC concrete, which arose out of stable hydrates due to pozzolan reaction of fly ash. Time-parameter of FA concrete is evaluated to be about 1.5 times larger than that of OPC concrete. Also, time-parameter of FA concrete has a linearly decreasing relation while that of OPC concrete has a linearly increasing relation with compressive strength development.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.133-144
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• 2003

Horizontal consolidation characteristics of Busan marine clay were investigated by computing coefficient of horizontal consolidation from Piezocone data and comparing their results with those of standard consolidation test. It is well known that current prediction models of $c_h$ for high plastic soils have large uncertainties, and show a great difference between the predicted and the measured values. However, the spherical models and expanding cavity theory of Torstensson(1977), and Burns & Mayne(1998) based on modified Cam-Clay model with critical limit state concepts have relative reliability in estimating $c_h$ and good applicability in highly plasticity soils. In this paper, a normalization technique was used to evaluate $c_h$ using the Burns and Mayne's method based on the dissipation test, and their normalized consolidation curves give 0.015 of time factor($T_{50}$) when 50% degree of consolidation is completed. Comparison study using Piezocone data obtained at other similar ground site shows 1.5 times less systematicality than that of standard consolidation test, which indicates considerable approximation with the measured values because standard consolidation test gives the difference of three to few times compared with the measured values. In addition, design chart for estimating $c_h$ based on the chart from Robertson et al.(1992) and using the other method of the direct prediction from the of dissipation test was newly proposed. It is judged that new proposed chart is very applicable to Korean marine soils, especially in very high plastic soils.

• The Journal of the Acoustical Society of Korea
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• v.24 no.1
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• pp.29-37
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• 2005

This paper proposes an automatic genre classification system for Korean traditional music. The Proposed system accepts and classifies queried input music as one of the six musical genres such as Royal Shrine Music, Classcal Chamber Music, Folk Song, Folk Music, Buddhist Music, Shamanist Music based on music contents. In general, content-based music genre classification consists of two stages - music feature vector extraction and Pattern classification. For feature extraction. the system extracts 58 dimensional feature vectors including spectral centroid, spectral rolloff and spectral flux based on STFT and also the coefficient domain features such as LPC, MFCC, and then these features are further optimized using SFS method. For Pattern or genre classification, k-NN, Gaussian, GMM and SVM algorithms are considered. In addition, the proposed system adopts MFC method to settle down the uncertainty problem of the system performance due to the different query Patterns (or portions). From the experimental results. we verify the successful genre classification performance over $97{\%}$ for both the k-NN and SVM classifier, however SVM classifier provides almost three times faster classification performance than the k-NN.