• 한국의류학회지
• /
• 제35권11호
• /
• pp.1271-1284
• /
• 2011

This study improves the fitness of Air Force winter service uniforms through the development of a shirt pattern drafting method and automatic pattern drafting program for MTM production. A calculation formula is formed through a correlation analysis and regression analysis using Size Korea 2004 3D measurement data after analyzing 4 kinds of existing shirt pattern drafting methods and 3 types of shirt patterns currently used for the Air Force service uniform. The results of this study are as follows: The developed pattern drafting method has 4 parts that use calculated dimensions: neck base width, front interscye, back interscye and scye depth. Other body measuring parts that have a high correlation with calculation parts are inserted into regression analysis as independent variables to create dimension calculation formulas. The result of the final study patterns were better than existing winter service uniforms in nearly all items for the appearance evaluation and motion adaptability evaluations. The method was converted into an automatic pattern drafting program using C++ after the completion of pattern drafting method development.

• Journal of Power Electronics
• /
• 제19권5호
• /
• pp.1289-1302
• /
• 2019

In this paper, an optimal allocation method of a hybrid active power filter in an active distribution network is designed based on the differential evolution algorithm to resolve the harmonic generation problem when a distributed generation system is connected to the grid. A distributed generation system model in the calculation of power flow is established. An improved back/forward sweep algorithm and a decoupling algorithm are proposed for fundamental power flow and harmonic power flow. On this basis, a multi-objective optimization allocation model of the location and capacity of a hybrid filter in an active distribution network is built, and an optimal allocation scheme of the hybrid active power filter based on the differential evolution algorithm is proposed. To verify the effect of the harmonic suppression of the designed scheme, simulation analysis in an IEEE-33 nodes model and an experimental analysis on a test platform of a microgrid are adopted.

• 터널과지하공간
• /
• 제15권5호
• /
• pp.344-351
• /
• 2005

터널 시공 중 계측한 변위 등으로 터널의 안정성을 재평가하기 위해 심플렉스 이론을 기초로 직접법 역해석 소프트웨어를 개발하고 그 정확성을 12 가지 조건에서 검증하였다. 이 소프트웨어는 FLAC을 부프로그램(subroutine)으로 하고 그것에 내장된 전산언어를 이용한 것이다. 변위 수 3-240개로 구성된 여러 가지 변위조합에 대한 역해석 검증결과 터널 주변의 계측위치와 입력변위의 개수에 관계없이 암반의 탄성계수와 초기응력 비를 구할 수 있었고 반복계산을 위한 출발값의 탄성계수와 초기응력 비에 관계없이 정해에 안정적으로 수렴되는 것을 확인하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 A
• /
• pp.452-454
• /
• 2001

This paper described the calculation results of lightning flashover rate on the 345kV and 154kV transmission system of KEPCO. The back-flashover rate and shielding failure rate was calculated by FLASH(lightning flashover rate calculation program from IEEE) and KEPRI's own program which is based on the EGM(Electro Geometrical Model) method. The estimated lightning flashover late of 345kV transmission system of double circuit was 1.0 flash per 100km-year, and the lightning flashover rate of 154kV transmission line was 2.0 flash Per 100km-year approximately.

• 전력전자학회논문지
• /
• 제13권1호
• /
• pp.33-40
• /
• 2008

본 논문은 단상 스위치드 릴럭턴스 모터의 역기전력 분석을 통해 회전자 위치를 추정하여 구동하는 센서리스 구동법을 제안한다. SRM은 회전자 위치에 따라 적정 고정자 권선을 여과시킴으로써 회전력을 발생하기 때문에 회전자 위치 정보가 필수적으로 요구된다. 회전자의 위치를 검출하기 위하여 다양한 회전자 위치센서를 사용하고 있으나 대부분의 위치 센서들은 모터의 부피와 구축비용을 증가시킬 뿐만 아니라 환경에 따라 구동시스템의 신뢰도를 저하시키는 경향이 있다. 따라서 본 논문에서는 이러한 문제들을 해결하기 위해 역기전력을 이용한 방법을 제안한다. 회전자와 고정자가 겹쳐지는 순간(overlap point) 역기전력이 급격하게 변화하게 되는 지점을 검출하여 회전자의 위치를 추정할 수 있으며, 속도 계산을 통해 적절한 위치에서 스위치를 온, 오프하여 SRM을 구동하게 된다. 본 연구에서 제안한 방식을 시뮬레이션과 실험을 통해 그 타당성을 검증하였다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• pp.601-606
• /
• 1993

From the power plants in a steel plant, environment pollutants such as SOx, NOx, CO are emitted by the combustion reaction between the fuels those are by-product gases and oil. To reduce the amounts of the pollutants, it must be important that build the predictive models for the emission of the pollutants. In this paper, the model that predict the amount of future fuel consumption and the model that predict the amount of generated pollutants for the used fuel amounts is developed by using Gibb's free energy minimization method with the temperature correction techniques and neural network back propagation method. For some data set, the calculation results from this models are compared with the real emission amounts of SOx, NOx and result of the calculation by the ASPEN plus which is a commercial software. The result from this model is better than the result by ASPEN plus for this problem.

• 조명전기설비학회논문지
• /
• 제28권12호
• /
• pp.6-12
• /
• 2014

The safety and reliability of the power system short-circuit current, the short-circuit current depends on the failure to obtain the objective is to quickly eliminate the breaking capacity of the circuit-breaker selection of the cable, the insulation of electrical equipment and protective relay an important factor in determining the level correction and protective relay selection scheme to be meaningful. Standards used in the domestic circuit breaker is applied to the production of IEC standard, but the American National Standards (ANSI / IEEE) by NEMA specification of the fault current calculations and the application of the asymmetric coefficient Korea. Therefore, in this paper, the IEC 60909 standard IEC breaker fault current calculation method and the method for selection of system configurations reviewed and protection system for reviewing the configuration of various protective relays appropriate correction and the correction value is main protection, back-up protection the equipment so that the period of protection relay coordination to minimize accidents and accident protection to minimize interruptions proposed for cooperation.

• 한국초전도ㆍ저온공학회논문지
• /
• 제12권2호
• /
• pp.13-16
• /
• 2010

The superconducting synchronous motor or generator mostly has high permeability iron only around outer yoke portion. Therefore, if excitation voltage (Back E.M.F) is calculated from 2 dimensional magnetic field distributions, it can be largely different from actual value due to additional voltage originated from end coils. In order to calculate the excitation voltage more accurately, 3 dimensional magnetic field calculation is necessary for including the end coil effect from large air-gap structure. The excitation voltage can be calculated by stator (armature) coil linkage flux originated from rotor (field) coil excitation, but it is difficult to calculate the flux linkage exactly because of complicated structure of the stator coil. This paper shows a method to calculate the excitation voltage from 3 dimensional magnetic energy that can be calculated directly from volume integration of magnetic flux density and field intensity scalar product through FEM (Finite Element Method) analysis software.

• Geomechanics and Engineering
• /
• 제19권2호
• /
• pp.115-126
• /
• 2019

The long-term settlement characteristics for the cast-in-place bored pile in the deep-thick soft soil are investigated by post-grouting field tests. Six cast-in-place bored engineering piles and three cast-in-place bored test piles are installed to study the long-term settlement characteristics. Three post-grouting methods (i.e., post-tip-grouting, post-side-grouting, and tip and side post-grouting) are designed and carried out by field tests. Results of the local test show that decreased settlements for the post-side-grouted pile, the post-tip-grouted pile and the tip and side post-grouted pile are 22.2%~25.8%, 30.10%~35.98% and 32.40%~35.50%, respectively, compared with non-grouted piles. The side friction resistance for non-grouted piles, post-side-grouted pile, post-tip-grouted pile and the tip and side post-grouted pile undertakes 89.6~91.3%, 94.6%, 92.4%~93.0%, 95.7% of the total loading, respectively. At last, the parameters back analysis method and numerical calculation are adopted to predict the long-term settlement characteristics of the cast-in-place bored pile in the deep-thick soft soil. Determined Bulk modulus (K) and a creep parameter (Ks) are used for the back analysis of the long-term settlement of the post-grouted pile. The settlement difference between the back analysis and the measurement data is about 1.11%-7.41%. Long-term settlement of the post-grouted piles are predicted by the back analysis method, and the predicted results show that the settlement of the post-grouted pile are less than 6 mm and will be stable in 30 days.

• 전기학회논문지
• /
• 제67권5호
• /
• pp.635-643
• /
• 2018

This paper propose a method to identify the motor parameters and improve input voltage error which affect the low speed position error of the back-emf(back electromotive force) based sensorless algorithm and to secure the operation reliability and stability even in the case where the load fluctuation is severe and the start and low speed operation frequently occurs. In the model-based observer used in this paper, stator resistance, inductance, and input voltage are particularly influential factors on low speed performance. Stator resistance can cause resistance value fluctuation which may occur in mass production process, and fluctuation of resistance value due to heat generated during operation. The inductance is influenced by the fluctuation due to the manufacturing dispersion and at a low speed where the change of the current is severe. In order to find stator resistance and inductance which have different initial values and fluctuate during operation and have a large influence on sensorless performance at low speed, they are commonly measured through 2-point calculation method by 2-step align current injection. The effect of voltage error is minimized by offsetting the voltage error. In addition, when the command voltage is used, it is difficult to estimate the back-emf due to the relatively large distortion voltage due to the dead time and the voltage drop of the power device. In this paper, we propose a simple circuit and method to detect the voltage by measuring the PWM(Pulse Width Modulation) pulse width and compensate the voltage drop of the power device with the table, thereby minimizing the position error due to the exact estimation of the back-emf at low speed. The suitability of the proposed algorithm is verified through experiment.