• Title/Summary/Keyword: Global fitting

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Determination of the Elbow Transverse Joint Using the Helical Axis Concept and its Application to the Development of a Kinematic Arm Model (나선축 개념을 이용한 팔꿈치 관절의 3차원 회전축 측정과 측정 결과를 반영한 인체 팔 모델의 개발)

  • Woo, Bum-Young;Jung, Eui-S.;Yun, Myung-Hwan
    • Journal of Korean Institute of Industrial Engineers
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    • v.26 no.1
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    • pp.73-80
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    • 2000
  • To determine the exact direction and location of the human joint in motion is crucial in developing a more accurate human model and producing a more fitting artificial joint. There have been several reports on the biomechanical analysis of the joint to determine the anatomy and movement of joints. However, all the previous researches were made in vitro study, that is, they investigated the passive movement of the joint from cadavers and the suggested location of the joint axis was difficult to make practical applications due to the lack of the direction of joint axis. Also, in many biomechanical models, each joint axis is assumed to lie horizontally or vertically to the adjacent links. Such an assumption causes inherent inaccuracy. In this study, the direction and location of the transverse elbow axis was obtained with respect to the global coordinate system whose origin is on the lateral epicondyle of the humerus. The suggested result based on the global coordinate system lying on the external landmark will be helpful to understand the information of the axis and to make an application. From the experiments conducted for five subjects, the direction and location of the elbow transverse joint was determined for each subject by the helical axis method. A statistical validation was also performed to confirm the result. Finally, the result was applied to develop a simple elbow model which is a part of the kinematic arm model. The simple elbow movement model was developed to validate the significance of the result and the kinematic arm model was able to describe the geometry of any complex linkage system. As a result, the errors incurred from the proposed model were significantly reduced when compared to the ones from the previous approach.

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GLOBAL Hɪ PROPERTIES OF GALAXIES VIA SUPER-PROFILE ANALYSIS

  • Kim, Minsu;Oh, Se-Heon
    • Journal of The Korean Astronomical Society
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    • v.55 no.5
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    • pp.149-172
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    • 2022
  • We present a new method which constructs an Hɪ super-profile of a galaxy which is based on profile decomposition analysis. The decomposed velocity profiles of an Hɪ data cube with an optimal number of Gaussian components are co-added after being aligned in velocity with respect to their centroid velocities. This is compared to the previous approach where no prior profile decomposition is made for the velocity profiles being stacked. The S/N improved super-profile is useful for deriving the galaxy's global Hɪ properties like velocity dispersion and mass from observations which do not provide sufficient surface brightness sensitivity for the galaxy. As a practical test, we apply our new method to 64 high-resolution Hɪ data cubes of nearby galaxies in the local Universe which are taken from THINGS and LITTLE THINGS. In addition, we also construct two additional Hɪ super-profiles of the sample galaxies using symmetric and all velocity profiles of the cubes whose centroid velocities are determined from Hermite h3 polynomial fitting, respectively. We find that the Hɪ super-profiles constructed using the new method have narrower cores and broader wings in shape than the other two super-profiles. This is mainly due to the effect of either asymmetric velocity profiles' central velocity bias or the removal of asymmetric velocity profiles in the previous methods on the resulting Hɪ super-profiles. We discuss how the shapes (𝜎n/𝜎b, An/Ab, and An/Atot) of the new Hɪ super-profiles which are measured from a double Gaussian fit are correlated with star formation rates of the sample galaxies and are compared with those of the other two super-profiles.

Rethinking OTT regulation based on the global OTT market trends and regulation cases (OTT 서비스의 유형과 주요국의 규제 정책에 대한 고찰)

  • Kim, Suwon;Kim, Daewon
    • Journal of Internet Computing and Services
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    • v.20 no.6
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    • pp.143-156
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    • 2019
  • Discussion on OTT regulation has become fiercer, as OTT services' impacts on the global and domestic media market have been exponentially growing. In South Korea, it is argued that, on the basis of the similarity between television program and OTT's video content, OTT needs to be regulated in order to protect fair competition and to control sociocultural effects. In many of the discussions, developed countries' cases have been used for supporting OTT regulation. In this paper, we first analyzed the global OTT market trends based on our own categorization of OTT services. then we assessed the validity of the application of the foreign cases in the current OTT regulation debates in Korea. We proposed six OTT types (aggregation, mediation, mediation-aggregation, multi-screen, outlet, and outlet-linear) simultaneously considering service operator' origin, business model, content format, and content delivery. These services have been consistently evolving, and the OTT market has been increasingly competitive especially around content differentiation. Regulators must be wary of hastily introducing competition regulation to the dynamically innovating OTT market. The foreign cases, including the US, EU, the UK, and Japan, hardly seem to be appropriate bases for strengthening OTT regulation. Rather, they were focused more on promoting competition in the domestic media market and enriching the content ecosystem. Therefore, we need to consider revision of the outdated media regulation frameworks instead of fitting OTT under them, and to recognize the priority of securing practical jurisdiction on global service providers before capturing local players into the conventional regulation systems.

Application of a Geographically Weighted Poisson Regression Analysis to Explore Spatial Varying Relationship Between Highly Pathogenic Avian Influenza Incidence and Associated Determinants (공간가중 포아송 회귀모형을 이용한 고병원성 조류인플루엔자 발생에 영향을 미치는 결정인자의 공간이질성 분석)

  • Choi, Sung-Hyun;Pak, Son-Il
    • Journal of Veterinary Clinics
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    • v.36 no.1
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    • pp.7-14
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    • 2019
  • In South Korea, six large outbreaks of highly pathogenic avian influenza (HPAI) have occurred since the first confirmation in 2003 from chickens. For the past 15 years, HPAI outbreaks have become an annual phenomenon throughout the country and has extended to wider regions, across rural and urban environments. An understanding of the spatial epidemiology of HPAI occurrence is essential in assessing and managing the risk of the infection; however, local spatial variations of relationship between HPAI incidences in Korea and related risk factors have rarely been derived. This study examined whether spatial heterogeneity exists in this relationship, using a geographically weighted Poisson regression (GWPR) model. The outcome variable was the number of HPAI-positive farms at 252 Si-Gun-Gu (administrative boundaries in Korea) level notified to government authority during the period from January 2014 to April 2016. This response variable was regressed to a set of sociodemographic and topographic predictors, including the number of wild birds infected with HPAI virus, the number of wintering birds and their species migrated into Korea, the movement frequency of vehicles carrying animals, the volume of manure treated per day, the number of livestock farms, and mean elevation. Both global and local modeling techniques were employed to fit the model. From 2014 to 2016, a total of 403 HPAI-positive farms were reported with high incidence especially in western coastal regions, ranging from 0 to 74. The results of this study show that local model (adjusted R-square = 0.801, AIC = 954.5) has great advantages over corresponding global model (adjusted R-square = 0.408, AIC = 2323.1) in terms of model fitting and performance. The relationship between HPAI incidence in Korea and seven predictors under consideration were significantly spatially non-stationary, contrary to assumptions in the global model. The comparison between global Poisson and GWPR results indicated that a place-specific spatial analysis not only fit the data better, but also provided insights into understanding the non-stationarity of the associations between the HPAI and associated determinants. We demonstrated that an empirically derived GWPR model has the potential to serve as a useful tool for assessing spatially varying characteristics of HPAI incidences for a given local area and predicting the risk area of HPAI occurrence. Considering the prominent burden of HPAI this study provides more insights into spatial targeting of enhanced surveillance and control strategies in high-risk regions against HPAI outbreaks.

Effects of Tropospheric Mapping Functions on GPS Data Processing

  • Won, Ji-Hye;Park, Kwan-Dong;Ha, Ji-Hyun;Cho, Jung-Ho
    • Journal of Astronomy and Space Sciences
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    • v.27 no.1
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    • pp.21-30
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    • 2010
  • In processing space geodetic data, mapping functions are used to convert the tropospheric signal delay along the zenith direction to the line of sight direction. In this study, we compared three mapping functions by evaluating their effects on the tropospheric signal delay and position estimates in GPS data processing. The three mapping functions tested are Niell Mapping Function (NMF), Vienna Mapping Function 1 (VMF1), and Global Mapping Function (GMF). The tropospheric delay and height estimates from VMF1 and GMF are compared with the ones obtained with NMF. The differences among mapping functions show annual signals with the maximum occurring in February or August. To quantitatively estimate the discrepancies among mapping functions, we calculated the maximum difference and the amplitude using a curve fitting technique. Both the maximum difference and amplitude have high correlations with the latitude of the site. Also, the smallest difference was found around $30^{\circ}N$ and the amplitudes increase toward higher latitudes. In the height estimates, the choice of mapping function did not significantly affect the vertical velocity estimate, and the precision of height estimates was improved at most of the sites when VMF1 or GMF was used instead of NMF.

Vibration transfer characteristic of foaming sponge seat with the auxiliary member for movie theater chair (보조재를 갖는 영화관 의자용 발포스펀지 시트의 진동전달 특성)

  • Kim, Sung-Hwan;Kang, Hwa-Joong;Moon, Deok-Hong
    • Journal of Power System Engineering
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    • v.17 no.6
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    • pp.40-46
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    • 2013
  • This paper describes the suggestion of the special seat with the auxiliary plastic member for movie theater chair. In the previous paper, we have reported on the development of foaming sponge seat with the auxiliary spring member. And we have confirmed that it was more effective on vibration transfer than the chair seat of foaming sponge only. In this study, we have examined the major design parameters needed in the development of a foaming sponge seat in which the mesh type plastic member are inserted to improve the vibration transfer effect of a chair seat. By applying experimentation to the prototype as well as the experimental modal analysis method, we made sure that the effect of the vibration transfer could be improved through the use of a mesh type plastic member as similar as the auxiliary spring member.

Questionnaire Study for Commercialization of Souvenir T-shirts (티셔츠 제품의 관광문화상품화를 위한 맞음새 만족도 조사)

  • Lee, Hyun-Hwa;Nam, Yun-Ja;Choi, Young-Lim
    • Fashion & Textile Research Journal
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    • v.11 no.4
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    • pp.614-620
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    • 2009
  • This study surveyed Koreans' as well as foreigners' satisfaction about the size and appropriateness of size label for souvenir T-shirts currently selling in domestic and overseas countries. Questionnaire survey was conducted to 205 Koreans who located in overseas and foreigners who located in Korea. The questionnaire was composed with T-shirts purchasing, difficulties in size selection, and satisfaction of fitness and prepared in Korean and english version. The survey revealed that the most dissatisfaction with the size of souvenir T-shirts concerned difficulty in finding appropriate sizes due to discrepancy between size systems different among countries and actual T-shirt size. Particularly, the participants showed relatively low degree of satisfaction with the area of shoulders and necks. When the size satisfaction was compared across countries, there were significant differences in shoulder width, shoulder length, and neck circumference. The satisfaction with shoulder width was also different depending on gender. Female participants' satisfaction was significantly lower than that of male participants.

KNOWLEDGE-BASED BOUNDARY EXTRACTION OF MULTI-CLASSES OBJECTS

  • Park, Hae-Chul;Shin, Ho-Chul;Lee, Jin-Sung;Cho, Ju-Hyun;Kim, Seong-Dae
    • Proceedings of the IEEK Conference
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    • 2003.07e
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    • pp.1968-1971
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    • 2003
  • We propose a knowledge-based algorithm for extracting an object boundary from low-quality image like the forward looking infrared image. With the multi-classes training data set, the global shape is modeled by multispace KL(MKL)[1] and curvature model. And the objective function for fitting the deformable boundary template represented by the shape model to true boundary in an input image is formulated by Bales rule. Simulation results show that our method has more accurateness in case of multi-classes training set and performs better in the sense of computation cost than point distribution model(PDM)[2]. It works well in distortion under the noise, pose variation and some kinds of occlusions.

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Fashion technical design education models applying the constructivism learning theory (구성주의 학습이론을 적용한 패션 테크니컬 디자인 교육 모형)

  • Im, Min-Jung
    • Journal of the Korea Fashion and Costume Design Association
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    • v.21 no.1
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    • pp.115-129
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    • 2019
  • This study aimed to develop methods for technical design education that can be intimately connected to the industrial field. For this, technical design jobs performed in the fields of the domestic and foreign fashion industries and their required competences were examined, and educational methods based on constructivism were proposed. Korean fashion technical designers' works were identified, and then the fashion technical designer's responsibilities and qualifications were collected and analyzed from global employment sites. On the basis of the collection and analysis, hands-on staff members and education experts were interviewed about required competences for the actual business and possible suitable methods for education. The results of research showed that in the case of the US, job systems and relevant duties for technical designers were clearly defined by clothing brands, whereas in Korea, businesses were systematized around vendors, not brands, and as a result the businesses of technical package composition and specification proposals were not performed properly. This study organized the contents of technical design education into fit development and specification, the composition of technical design packages, the evaluation and approval of samples, fit schedule management and fitting, block pattern setting and pattern correction, sewing specifications appropriate for styles and materials, grading, technical terms, and production management. As for the technical design education models, the cognitive apprenticeship model, resource-based learning, the problem-based and anchored model, and the problem-based and resource-based models were proposed.

Regional Optimization of NeQuick G Model for Improved TEC Estimation (NeQuick G의 TEC 예측 개선을 위한 지역 최적화 기법 연구)

  • Jaeryoung Lee;Andrew K. Sun;Heonho Choi; Jiyun Lee
    • Journal of Positioning, Navigation, and Timing
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    • v.13 no.1
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    • pp.63-73
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    • 2024
  • NeQuick G is the ionosphere model utilized by Galileo single-frequency users to estimate the ionospheric delay on each user-satellite link. The model is characterized by the effective ionization level (Az) index, determined by a modified dip latitude (MODIP) and broadcast coefficients derived from daily global space weather observations. However, globally fitted Az coefficients may not accurately represent ionosphere within local area. This study introduces a method for regional ionospheric modeling that searches for locally optimized Az coefficients. This approach involves fitting TEC output from NeQuick G to TEC data collected from GNSS stations around Korea under various ionospheric conditions including different seasons and both low and high solar activity phases. The optimized Az coefficients enable calculation of the Az index at any position within a region of interest, accounting for the spatial variability of the Az index in a polynomial function of MODIP. The results reveal reduced TEC estimation errors, particularly during high solar activity, with a maximum reduction in the RMS error by 85.95%. This indicates that the proposed method for NeQuick G can effectively model various ionospheric conditions in local areas, offering potential applications in GNSS performance analyses for local areas by generating various ionospheric scenarios.