• Journal of Magnetics
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• v.21 no.3
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• pp.399-404
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• 2016

This paper presents a new permanent magnet (PM) assisted topology for a recently introduced brushless wound rotor synchronous machine (BL-WRSM) [1]. The BL-WRSM had a dual-inverter configuration for generating a composite magneto motive force (MMF) with a fundamental component and a subharmonic component. The subharmonic component of the MMF is used for brushless excitation of the rotor. In this paper, additional PMs were introduced on the rotor of the BL-WRSM, making it a hybrid BL-WRSM. We also discussed the flux weakening operation for the hybrid BL-WRSM. The hybrid BL-WRSM offered advantages for starting the machine and provided better performance under full-load conditions. The finite element method (FEM) was used to analyze the performance of the hybrid BL-WRSM, and we compared its performance with BL-WRSM. Finally, prototypes were built with and without the PM-assistance, and experiments were conducted to demonstrate their performance.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.753-756
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• 2003

The paper presents the results of the project GISMO, which aimed on generating and interactively visualising a 3D urban landscape model of the city of Stuttgart, Germany. With respect to the desired flexibility to support walkthrough and flyover applications, a combined approach using continuous level of detail, the impostor technique and a method for generalizing 3D building models was used to speed up the visualization. To reduce the costs of the project, the data collection tools and the visualization environment was built solely with open-source software.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1089-1090
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• 2011

This paper presents a novel two-phase two-pole permanent magnet synchronous motor (PMSM) with asymmetric U-core stator structure. The construction and parameters of the novel two-phase U-core PMSM are compared with a conventional U-core single-phase PMSM (SPMSM). Then transient characteristics such as torque, back-emf, and power loss of the both PMSMs are analyzed by using 3-D Finite Element Method (FEM). Under the same condition of rated input current, synchronous speed, similar dimensions and volume, FE results show that the two-phase PMSM with U-core stator has significantly less torque ripple than single-phase U-core PMSM, with similar power loss and efficiency.

• Journal of Chest Surgery
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• v.25 no.9
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• pp.891-899
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• 1992

Esophageal atresia with tracheoesophageal fistula may occur as separate, but usually occur in combination. First described by Thomas Gibson in 1696, esophageal atresia was not successfully treated until 1939 when the first two survivors of staged correction were described by Ladd and Leven. In 1941, Haight and Towsley performed the first successful one-stage primary repair. We report three cases of esophageal atresia with tracheoesophageal fistula of which were treated with one-stage surgical repair method. The operation was performed tra-nspleurally through right 4th intercostal space. The fistula in the trachea was closed with interrupted 5-O prolene sutures and esophagoesophageal anastomosis was performed with 3-O prolene single layer sutures in all cases. All patients tolerated the operative procedures and recovered uneventfully. On follow-up study, anastomotic stricture was developed in one patients, so esophageal dilatation was performed for it with the Griintzig balloon catheter and the result was satisfactory. The other patients were well-being without any complication.

• International Journal of Contents
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• v.13 no.2
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• pp.66-74
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• 2017

Patent classification is becoming more critical as patent filings have been increasing over the years. Despite comprehensive studies in the area, there remain several issues in classifying patents on IPC hierarchical levels. Not only structural complexity but also shortage of patents in the lower level of the hierarchy causes the decline in classification performance. Therefore, we propose a new method of classification based on different criteria that are categories defined by the domain's experts mentioned in trend analysis reports, i.e. Patent Landscape Report (PLR). Several experiments were conducted with the purpose of identifying type of features and weighting methods that lead to the best classification performance using Support Vector Machine (SVM). Two types of features (noun and noun phrases) and five different weighting schemes (TF-idf, TF-rf, TF-icf, TF-icf-based, and TF-idcef-based) were experimented on.

• Journal of the Korean Statistical Society
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• v.25 no.4
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• pp.499-514
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• 1996

Consider an additive regression model of Y on X = (X$_1$,X$_2$,. . .,$X_p$), Y = $sum_{j=1}^pf_j(X_j) + $\varepsilon$$, where $f_j$s are smooth functions to be estimated and $\varepsilon$ is a random error. If $X_j$s are fixed design points, we call it the fixed design additive model. Since the response variable Y is observed at fixed p-dimensional design points, the behavior of the nonparametric regression estimator depends on the design. We propose a fixed design called permutation fixed design, and fit the regression function by the kernel method. The estimator in the permutation fixed design achieves the univariate optimal rate of convergence in mean squared error for any p $\geq$ 2.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.520-529
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• 2006

그 동안 몇 차례 오스터버그 셀$(O-cell^{\circledR})$을 이용한 양방향 말뚝 재하시험기법이 국내에 성공적으로 소개/적용된 바 있다. 이 방법은 상대적으로 새롭고 독특한 방법으로서 시험비용과 기존 재래적인 시험방법이 적용상 제한을 받는 경우나 대규모 시험에서 발생할 수 있는 문제점들을 극복할 수 있다. 국내에서는 설계목적을 위한 시험말뚝 뿐 아니라 설계하중이 큰 실제말뚝에 대한 시험이 증가하는 추세에 있다. 이 논문에서 소개하는 양방향 재하시험 방법을 적용하면 기존의 소규모 재하시험 방법에서 발생될 수 있는 주면 마찰력과 선단지지력의 분리측정이나 각각의 지지력에 대한 극한상태를 확인하지 못하는 한계를 극복할 수 있고 시험하중이 270MN을 초과하는 경우까지 적용할 수 있는 장점을 갖고 있다. 본 논문에서는 오스터버그 셀을 이용한 정적 재하시험 방법에 대하여 말뚝종류별로 상세히 기술하였으며 이 시험방법의 장점과 국내현장에 적용되었던 사례를 소개하였다.

• Transactions of Materials Processing
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• v.24 no.6
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• pp.387-394
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• 2015

Air springs are designed to support loads using the volume elasticity in a cylindrical shaped air bag made of a composite material with a rubber matrix and two plies of reinforced fibers. Recently, applications of these springs have been expanded from railway vehicles to passenger cars. The current study presents a finite element analysis of a manufactured air spring for a passenger car. The analysis was conducted including the mounting steps of the air bag using a static loading condition. A method for controlling the internal pressure and displacements during the mounting step was developed. The characteristic load curve and the shape of the air bag were in good agreement with the experimental data with respect to the design height, the bump height and the rebound height. Results indicate that ply angles of fibers vary from 38 degrees to 56 degrees during static loading.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.834-839
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• 2003

Previous research has been conducted on an ultrasonic wave reflection method that utilizes a steel plate embedded in the concrete to measure the reflection loss of shear waves at the steel-concrete interface. The reflection loss has been shown to have a linear relationship to compressive strength at early ages. The presented investigations continue this research by examining the fundamental relationship between the reflection loss, measured with shear waves, and the hydration kinetics of Portland cement mortar, represented by dynamic elastic moduli, compressive strength and degree of hydration. Dynamic elastic moduli are measured by fundamental resonant frequency and degree of hydration is determined by thermogravimetric analysis. The water/cement ratio was varied for the tested mixture compositions. The results presented herein show that compressive strength, dynamic shear modulus and degree of hydration have a linear relationship to the reflection loss for the tested mortars at early ages.

• Journal of the Korean Chemical Society
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• v.62 no.2
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• pp.99-105
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• 2018

In this paper, we present fortified instructional methods that contributed in improving students' interest toward the expository organic chemistry laboratory course. Reformed TA (Teaching assistant) training and allocation method, a thorough course orientation session, text-light/graphics-heavy results PPT reports, and journal article templated-term papers have improved students' satisfaction in the organic chemistry laboratory course. These methods could be implemented while maintaining the traditional organic chemistry laboratory instruction styles and hence could be broadly applicable.