• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.3
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• pp.50-57
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• 2003

In the paper, the design and evaluation of a helicopter trajectory tracking controller are presented. The control algorithm is implemented using the feedback linearization technique and the two time-scale separation architecture. In addition, and on-line adaptive architecture that employs a neural network compensating the model inversion error caused by the deficiency of full knowledge of helicopter dynamic is applied to augment the attitude control system. Trajectory tracking performance of the control system in evaluated using modified TMAN simulation program representing as Apache helicopter. It is show that the on-line neural network in an adaptive control architecture is very effective in dealing with the performance depreciation problem of the trajectory tracking control caused by insufficient information of dynamics.

• Clinics in Shoulder and Elbow
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• v.18 no.2
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• pp.80-85
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• 2015

Background: This study measured the rate of adrenal insufficiency among rotator cuff tear patients, and determined the roles of steroid treatment and herbal medicine as specific risk factors of adrenal insufficiency. Methods: We prospectively evaluated the 53 patients who agreed to participate in the study and underwent arthroscopic rotator cuff repair due to a chronic full-thickness tear from March 2012 to September 2013. The diagnosis of adrenal insufficieny was made by rapid adrenocortical hormone test before the operation. We collected information regarding their history of steroid and herbal medicine treatment within the last 12 months. Results: The rate of adrenal insufficiency among the rotator cuff tear patients in our study was 18.9% (10 of 53 patients). Steroid treatment (p=0.034), frequency of local steroid injection (p=0.008), and herbal medicine treatment (p=0.02) showed significant association with the risk of adrenal insufficiency. Conclusions: In this study, careful taking of a patient's medical history, such as the use of steroids and herbal medicine, is important when investigating adrenal function before surgery.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.2 s.95
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• pp.148-155
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• 2005

As functional requirement of massive digital information storage devices are on a trend for the higher data transfer rate and lower cost, many different technical efforts are being tested and implemented in the industry. FDB(fluid dynamic bearing) is one of the major breakthroughs in rotor design in terms of TMR(track misregistration) budget. Although FDB analysis based on Reynolds' equation is well established and popularly being used for FDB design especially for the estimation of bearing stiffness, there are obvious limitations in the approach due to the inherent assumptions. A generalized analysis tool employing the full Navier-Stokes equation and the energy balance is to be beneficial for detailed FDB design. In this publication, an efficient geometry modeling method is presented that provides fully integrated inputs for general FVM/FDM(finite volume method/ finite difference method) codes. By virtue of the flexibility of the presented method, many different detailed FDB design and analysis are carried over with ease.

• Journal of Fashion Business
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• v.17 no.6
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• pp.76-87
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• 2013

The purpose of this study is to understand how the silhouette changed throughout 1970s and assess how US women express their identities through their dress, which may explain societies' attitudes through the way women dresses. US Vogue fashion magazines were used to explore all the information on fashion and style trends, social trends, beauty, and travel. A content analysis was performed on the issues of the March and September for the years 1970 to 1979. The findings for this study about the 1970s were all about perpetual change, constantly moving forward with innovation. The color ranged from bright, cheery and bold to deep and passionate to subtle neutrals. There were a few constant colors through the decade like white, black and navy. Occasionally the trend would completely change from one season to the next within the same year. They would be full and oversized and then be slim and body conscious. The one trend that stayed true for the entire decade was wrapping. Skirts, pants, dresses, tops, shoes and jewelry; everything wrapped in one-way or another. Clothes steadily became more revealing as the years progressed. Fabrics over all were soft and knitted. Casual and comfortable was the phase heard most often. In the 1970s there was constant change in prints. They were bold and large or subtle and small, ethnic or floral. Hair was mostly smooth and sleek however towards the style moved to a fuller look.

• Journal of the Korea Safety Management & Science
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• v.15 no.2
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• pp.255-262
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• 2013

Due to the competition between the various professional events, it is imperative for the team's management to improve efficiency by removing the inefficiencies of the professional team in order to gain a competitive edge. This study use different Data Envelopment Analysis (DEA) models to measure the efficiency of professional sport organizations. In this mathematical-analytical study, this study first reviews the related literature to analyze the input/output variables. In the end, the variables were detected and the data for this study were gathered from the Korean Basketball League (KBL). While previous studies examine relative efficiency of Korean Professional baseball teams by using CCR model, this study fully utilize the DEA method to investigate Korean professional sports organizations' operating problem. Thus, this study propose full results of DEA analysis such as efficiency score (overall, technical, and scale efficiency), slacks in inputs and outputs of inefficient organizations, Malmquist index) As a result, this study provides not only the exact productivity information of a team and a way of improving a firm's productivity with a decision maker.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.4
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• pp.127-138
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• 1997

In this study, a new technique is presented, by which one can define ship hull form with full fairness from the input data of lines. For curve modeling, the de Casteljau Algorithm and Bezier control points are used to express free curves and to establish the unified curve modeling technique which enables one to convert non-uniform B-spline (NUB) curve or cubic spline curve into composite Bezier curves. For surface modeling, the mesh curve net which is required to define surface of ship hull form is interpolated by the method of the unified curve modeling, and the boundary curve segments of Gregory surface patches are generated by remeshing(rearranging) the given mesh curve net. From these boundary information, composite Gregory surfaces of good quality in fairness can be formulated.

• Communications for Statistical Applications and Methods
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• v.14 no.3
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• pp.483-495
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• 2007

In a general fractional factorial design, the n-levels of a factor are coded by the $n^{th}$ roots of the unity. Pistone and Rogantin (2007) gave a full generalization to mixed-level designs of the theory of the polynomial indicator function using this device. This article discusses the optimal blocking scheme for nonregular designs. According to hierarchical principle, the minimum aberration (MA) has been used as an important criterion for selecting blocked regular fractional factorial designs. MA criterion is mainly based on the defining contrast groups, which only exist for regular designs but not for nonregular designs. Recently, Cheng et al. (2004) adapted the generalized (G)-MA criterion discussed by Tang and Deng (1999) in studying $2^p$ optimal blocking scheme for nonregular factorial designs. The approach is based on the method of replacement by assigning $2^p$ blocks the distinct level combinations in the column with different blocks. However, when blocking level is not a power of two, we have no clue yet in any sense. As an example, suppose we experiment during 3 days for 12-run Plackett-Burman design. How can we arrange the 12-runs into the three blocks? To solve the problem, we apply G-MA criterion to nonregular mixed-level blocked scheme via the mixed-level indicator function and give an answer for the question.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.4
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• pp.237-244
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• 2013

Radar remote sensing is appropriate for monitoring rice because the areas where this crop is cultivated are often cloudy and rainy. Especially, Synthetic Aperture Radar (SAR) can acquire remote sensing information with a high temporal resolution in tropical and subtropical regions due to its all-weather capability. This paper analyzes the relationships between backscattering coefficients of rice measured by RADARSAT-2 SAR and growth parameters during a rice growth period. We examined the temporal variations of backscattering coefficients with full polarization. Backscattering coefficients for all polarizations increased until Day Of Year (DOY 222) and then decreased along with Leaf Area Index (LAI), fresh weight, and Vegetation Water Content (VWC). Vertical transmit and Vertical receive polarization (VV)-polarization backscattering coefficients were higher than Horizontal transmit and Horizontal receive polarization (HH)-polarization backscattering coefficients in early rice growth stage and HH-polarization backscattering coefficients were higher than VV-polarization backscattering coefficients after effective tillering stage (DOY 186). Correlation analysis between backscattering coefficients and rice growth parameters revealed that HH-polarization was highly correlated with LAI, fresh weight, and VWC. Based on the observed relationships between backscattering coefficients and variables of cultivation, prediction equations were developed using the HH-polarization backscattering coefficients.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.11
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• pp.1015-1022
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• 2013

This study simulates the operation of a 200 kW class micro gas turbine that is currently under development. The performance and operating characteristics depending on the load control scheme (constant turbine inlet temperature versus constant turbine exit temperature) and ambient condition were investigated using detailed component performance data. The sensitivities of operating parameters, such as the compressor surge margin and flow path temperatures, according to unit fuel flow change were predicted for a wide load range. The sensitivity analysis showed that the steady state calculation provided useful information about the maximum surge margin reduction during load change.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.383-392
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• 2014

Purpose: In this study, we sought to understand the risk factor for chronic disease of workers by studying the association between occupational standing time and metabolic syndrome(MetS) in full-time 300 male workers. Materials: Data on age, life habit, work related information of the subjects were surveyed using self-reported questionnaire and interview. MetS was identified based on the report of Alberti et al.(2009). As for the data analysis, SPSS 19.0 was used to conduct the descriptive statistic, ANOVA, Pearson correlation coefficient and multiple logistic regression analysis. Results: Daily working hour affects on the lifting heavy objects, running and strenuous exercise(r=-0.137, p<0.01), and total physical function decreased with the increase in age(r=-0.145, p<0.01). Also, obese was significantly associated with genuflection and bend over(r=-0.110, p<0.05). On multiple logistic regression analysis for the diagnostic indices of MetS, occupational standing time were significantly associated with waist circumference(odds ratio=0.885, ${\beta}$ value=-0.122, 95% CI=0.797-0.983, p<0.05) and triglyceride (odds ratio=0.873, ${\beta}$ value=-0.136, 95% CI=0.800-0.953, p<0.01). Conclusions: These results suggest that the working posture may be important risk factor in pathogenesis and growing of MetS and cardiovascular disease.