• 전기학회논문지
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• 제63권2호
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• pp.197-204
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• 2014

As more and more renewable energy resources are connected into the existing power system and their generation capacities are increasing, the need for regulations to minimize their impacts on the power grid is increasingly growing. And minimizing the irregular impacts made by grid-connected wind generators is important, since the output power generated by renewable energy resources can be changed easily by the weather condition and surrounding environment. In South Korea, an operational technical standard for distributed generation is used as a regulation, in which renewable energy sources including wind power are considered as a kind of distributed generation. In this paper, an international standard, IEC 61400-21, for the grid-connected wind turbine generating system(WTGS) will be introduced and a comprehensive and detailed review on the measuring methods of power quality characteristic parameters for WTGS based on the related IEC standards will be presented. Additionally, some prerequisites for applying the international standards to KEPCO system will be proposed.

• Computers and Concrete
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• 제7권4호
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• pp.365-386
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• 2010

This paper presents the physical formulation of a 1D material model suitable for seismic applications. It is written within the framework of thermodynamics with internal variables that is, especially, very efficient for the phenomenological representation of material behaviors at macroscale: those of the representative elementary volume. The model can reproduce the main characteristics observed for concrete, that is nonsymetric loading rate-dependent (viscoelasticity) behavior with appearance of permanent deformations and local hysteresis (continuum plasticity), stiffness degradation (continuum damage), cracking due to displacement localization (discrete plasticity or damage). The parameters have a clear physical meaning and can thus be easily identified. Although this point is not detailed in the paper, this material model is developed to be implemented in a finite element computer program. Therefore, for the benefit of the robustness of the numerical implementation, (i) linear state equations (no local iteration required) are defined whenever possible and (ii) the conditions in which the presented model can enter the generalized standard materials class - whose elements benefit from good global and local stability properties - are clearly established. To illustrate the capabilities of this model - among them for Earthquake Engineering applications - results of some numerical applications are presented.

• Current Research on Agriculture and Life Sciences
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• 제31권2호
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• pp.113-123
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• 2013

The carbon-offset mechanism based on forest management has been recognized as a meaningful tool to sequestrate carbons already existing in the atmosphere. Thus, with an emphasis on the forest-originated carbon-offset mechanism, the accurate measurement of the carbon stock in forests has become important, as carbon credits should be issued proportionally with forest carbon stocks. Various remote sensing techniques have already been developed for measuring forest carbon stocks. Yet, despite the efficiency of remote sensing techniques, the final accuracy of their carbon stock estimations is disputable. Therefore, minimizing the uncertainty embedded in the application of remote sensing techniques is important to prevent questions over the carbon stock evaluation for issuing carbon credits. Accordingly, this study reviews the overall procedures of carbon stock evaluation-related remote sensing techniques and identifies the problematic technical issues when measuring the carbon stock. The procedures are sub-divided into four stages: the characteristics of the remote sensing sensor, data preparation, data analysis, and evaluation. Depending on the choice of technique, there are many disputable issues in each stage, resulting in quite different results for the final carbon stock evaluation. Thus, the establishment of detailed standards for each stageis urgently needed. From a policy-making perspective, the top priority should be given to establishinga standard sampling technique and enhancing the statistical analysis tools.

• 한국컴퓨터산업학회논문지
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• 제4권12호
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• pp.943-952
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• 2003

그레이팅이라는 금속 제품의 자동 설계 시스템인 GDS (Grating automatic Drawing System)는 기본 설계 도면 (Plan Drawing)의 정보들을 바탕으로 여러 세부 도면들을 자동 생성하는 시스템이다. 그러나 GDS를 통해 자동 생성된 도면은 설계자들의 일반적인 치수 기입 요령을 부분적으로 만족시키지 못하고 있으며 또 치수 표시 간의 겹침 현상이 발생하여 설계자가 도면을 수정해야 하는 번거로움이 있었다. 전문가 시스템은 컴퓨터 시스템에 입력된 특정분야에서의 전문가적지식(knowledge)과 사실(fact)들을 이용하여 전문가의 지 식 이 요구되는 문제들을 해결하기 위해 만들어진 시스템이다. 본 논문은 이러한 문제점을 해결하기 위하여 선계 전문가들의 치수 표시법을 지식으로 하여 규칙 기반 전문가 시스템을 구성하였다.

• 전력전자학회논문지
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• 제8권4호
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• pp.328-335
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• 2003

본 논문에서는 전기자동차용 전동기/제어기를 시험하기 위한 절차를 제시하였다. 현재 전기자동차용 전동기/제어기의 시험에 관한 국제 규격은 주로 안전 운전을 위한 최소 기준치를 정의하고 있지만 상세한 시험 방법에 대해서는 기술하고 있지 않다. 시험 항목 및 방법을 개발하기 위하여 기존의 선진국 규격에 대하여 전문가들의 의견을 바탕으로 보완 작업을 수행하였다. 개발된 규격에 따라 전동기/제어기의 시험 방법을 제시하였으며 다양한 부하 장치를 사용할 경우의 시험 방법을 제시하였다. 시험 절차는 주로 전동기 제어기 조합시험에 주안점을 두었으며 부하 장치로는 전동기-발전기, 와전류형 엔진 다이나모, 교류 다이나모 등을 사용하였으며 전동기/제어기를 차량에 탑재하지 않은 상태에서 전동기/제어기의 실제 주행모드 운전 특성을 시험하기 위한 방법을 제시하였다.

• Progress in Superconductivity
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• 제6권1호
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• pp.24-31
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• 2004

Magnetic $T_{c}$ of composite superconductors has been studied for providing a standard method. Various magnetization-temperature curves of NbTi, $Nb_3$Sn and Bi-2223 wires were measured using a SQUID magnetometer. Magnetization-temperature curve of zero-field-cooled procedure showed larger values than fie Id-cooled procedure. To obtain higher resolution near the onset temperature, we employed a two-field-direction method which measures a magnetization-temperature curve of a specimen first in positive and then negative fields. Analytical comparison of the magnetic $T_{c}$, with the resistive T$_{c}$ was accomplished for three specimens. The magnetic $T_{c}$/ mettled showed more detailed information on superconducting state of a specimen than the resistive$T_{c}$/ method. We have also studied the field dependence of the magnetic $T_{c}$ from 5 Oe to 120 Oe, however, no significant difference on field strength was found in our three specimensns

• 한국태양에너지학회 논문집
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• 제36권5호
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• pp.9-18
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• 2016

G-SEED(Green Standard for Energy and Environmental Design) is the certification system to evaluate environmental friendliness of buildings for the purpose of reducing environmental burden generated from the entire process of buildings, which is classified into 4 grades according to the evaluated score. Green building certification rule regulate to get over green 2nd grade for the public office buildings of $3000m^2$ or more. However, detailed measures on the applied level of each issue to obtain targeted certification grade have not been prepared yet. For each issue, the score distribution and the ratio of score in proportion to credit were analyzed by certification grade for office buildings which get the G-SEED certification. And applied level of issues were presented for each certification grade.

• 대한간호학회지
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• 제34권2호
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• pp.290-296
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• 2004

Purpose: The purpose of this study was to develop a home care nursing network system for operating home care effectively and efficiently by utilizing a wire-wireless network and mobile computing in order to record and send patients' data in real time, and by combining the headquarter office and the local offices with home care nurses over the Internet. It complements the preceding research from 1999 by adding home care nursing standard guidelines and upgrading the PDA program. Method: Method/l and Prototyping were adopted to develop the main network system. Result: The detailed research process is as follows: 1 )home care nursing standard guidelines for Diabetes, cancer and peritoneal-dialysis were added in 12 domains of nursing problem fields with nursing assessment/intervention algorithms. 2) complementing the PDA program was done by omitting and integrating the home care nursing algorhythm path which is unnecessary and duplicated. Also, upgrading the PDA system was done by utilizing the machinery and tools where the PDA and the data transmission modem are integrated, CDMX-1X base construction, in order to reduce a transmission error or transmission failure.

• 한국문헌정보학회지
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• 제39권2호
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• pp.57-84
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• 2005

교구$\cdot$ 설비기준은 학교 교육과정을 위한 기본 요소를 의미한다. 지식기반사회에서 학교도서관은 교육과정을 지원하고 정보활용과 독서지도를 위한 기본적인 교육환경이다. 따라서 학교도서관 교구 설비기준은 학교도서관의 사명을 담아야 하며, 교육적 역할에 적합한 구성요소를 포함하여야 한다. 그러나 현행 기준은 양적 질적 측면에서 불충분하다. 따라서 학교교구·설비기준 개정 시, 학교도서관 교구 ·설비기준은 특히 다음과 같은 내용을 포함하여야 한다. 1. 시설 지침; 2. 기본 설비 방안; 3. 교육적 역할에 적합한 교구 기준; 4. 기본 공간별 설비 종목; 5. 보다 상세한 정보기기 종목; 6. 특수학교도서관 기준 개선

• 대한기계학회논문집A
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• 제30권10호
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• pp.1219-1226
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• 2006

The ASTM test standard recommends the use of the compact tension specimen for creep crack growth rates measurement. In the creep crack growth rate test, the displacement rate due to creep is obtained by subtracting the contribution of elastic and plastic components from the total load line displacement rate based on displacement partitioning method fur determining $C^*-integral$, which involves Ramberg-Osgood (R-O) fitting procedures. This paper investigates the effect of the R-O fitting procedures on plastic displacement rate estimates in creep crack growth testing, via detailed two-dimensional and three-dimensional finite element analyses of the standard compact tension specimen. Four different R-O fitting procedures are considered; (i) fitting the entire true stress-strain data up to the ultimate tensile strength, (ii) fitting the true stress-strain data from 0.1% strain to 0.8 of the true ultimate strain, (iii) fitting the true stress-strain data only up to 5% strain, and (iv) fitting the engineering stress-strain data. It is found that the last two procedures provide reasonably accurate plastic displacement rates and thus should be recommended in creep crack growth testing. Moreover, several advantages of fitting the engineering stress-strain data over fitting the true stress-strain data only up to 5% strain are discussed.