• 소성∙가공
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• 제22권6호
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• pp.334-339
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• 2013

Direct Laser Melting is a prototyping process whereby a 3-D part is built layer wise by melting the metal powder with laser scanning. This process is strongly influenced by the shielding gas and the laser operating parameters such as laser power, scan rate, layering thickness, and rescanning. The shielding gas is especially important in affecting the microstructure and mechanical properties. In the current study, fabrication experiments were conducted in order to analyze the effect of shielding gas on the forming characteristics of direct laser melting. Cylindrical parts were produced from a Fe-Ni-Cr powder with a 200W fiber laser. Surface quality, porosity and hardness as a function of the layering thickness and shield gas were evaluated. By decreasing the layering thickness, the surface quality improved and porosity decreased. The selection of which shield gas, Ar or $N_2$, to obtain better surface quality, lower porosity, and higher hardness was examined. The formability and mechanical properties with a $N_2$ atmosphere are better than those parts formed under an Ar atmosphere.

• Child Health Nursing Research
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• 제7권3호
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• pp.280-297
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• 2001

The purpose of the study was to develop and test the model for the quality of life in mothers of children with nephrotic syndrome. A hypothetical model was constructed on the basis of previous studies and a review of literature. The conceptual framework was built around ten constructs. Exogenous variables included in this model were mother's health, father's health, marital intimacy, mother's attitude on children, economic state, side effect of steroid, severity of illness and social support. Endogenous variables were mother's burden and quality of life. Empirical data for testing the hypothetical model were collected by using a self-report questionnaire from 152 mothers of children with nephrotic syndrom at the outpatient clinics and in the hospital. The data was collected from May, 1999 to August, 1999.Reliability of the seven instruments was tested with Cronbach's alpha which ranged from 0.71 - 0.92.For the data analysis, SPSS 8.0 WIN program and LISREL 8.20 WIN program were used for descriptive statistics and covariance structural analysis. The results of covariance structural analysis were as follow :1. The hypothetical model showed a good fit with the empirical data. [x2 = .56, df = 3, p = .90(p>.05 ), GFI = .99, AGFI = .99, RMSR = .005.] 2. For the parsimony of model, a modified model was constructed by deleting 1 variable and excluding 2 paths according to the criteria of statistical significance and meaning.3. The modified model also showed a good fit with the data[x2 = 2.83, df = 7, p = .90( p>.05 ), GFI = 1.00, AGFI = .97, RMSR = .011].The result of the testing of the hypothesis were as follows : 1. Mother's health(γ21 = .26, t = 4.16), father's health(γ22 = .19, t = 2.92), marital intimacy(γ23 = .26, t = 4.13) and social support(γ28 = .12, t = 2.03) had a significant direct effect on the quality of life.2. Mother's burden(β21 = -.20, t = -3.10) had a significant negative direct effect on the quality of life.3. Mother's attitude on children(γ14 = -.34, t = .-4.57), mother's health(γ11 = -.22, t = -2.96) and side effect of steroid (γ16 = -.23, t = .-2.69) had a significant direct negative effect on the burden. The result of this study showed that mother's health, marital intimacy, mother's burden, father's health, and social support had a significant direct effect on the quality of life. Mother's attitude on children, mother's health, and side effect of steroid had a significant direct effect on mother's burden. These six variables, mother's health, marital intimacy, father's health, social support, mother's attitude on children and side effect of steroid were identified as relatively important variables. The results of this study suggest, it needed to determine the nursing intervention will alleviate mother's burden and promote a greater quality of life in mothers of children with nephrotic syndrom.

• Journal of Animal Science and Technology
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• 제52권3호
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• pp.187-190
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• 2010

The objective of this study was to estimate genetic parameters for total number of born (TNB), number of born alive (NBA) and teat numbers (TN) of Landrace and Yorkshire breeds in Korean swine population using multiple trait animal model procedures. Total numbers of 4,653 records for teat numbers and 8,907 records for TNB and NBA collected from 2004 to 2008 on imported breeding pigs and their litter size records were used in this study. To find the appropriate model for estimation of genetic parameters (heritabilities and genetic correlations), five statistical models (two models for reproductive traits, two models for teat numbers, one model for combining these traits) considering only direct additive genetic effects, including maternal effects were used and Akaike information criteria (AIC) of each two models for reproductive traits and teat trait were compared. The means and standard deviations of TNB, NBA, and TN were $11.52{\pm}3.34$, $10.55{\pm}2.96$ and $14.30{\pm}0.83$, respectively. Estimated heritabilities for TNB and NBA traits using the model which considered only additive genetic effect were low (0.06 and 0.05, respectively). However, estimated heritabilities considering maternal genetic effects were a little bit higher than that of the model considering only additive genetic effect (0.09 for TNB and NBA, respectively). Estimated heritability for TN using the model which considered only additive genetic effect was 0.40. However, estimated heritability of direct genetic effects from a model considering maternal genetic effect was high (0.60). All results of AIC statistics, the models considering maternal effect was more appropriate than the models considering only additive genetic effect. Genetic correlations of direct additive genetic effect between litter size (TNB, NBA) and teat numbers were low (-0.18 and -0.14, respectively). However, genetic correlations of maternal effect between litter size (TNB, NBA) and teat numbers were a little bit higher than those of direct additive genetic effect (0.08 and 0.16, respectively).

• 통상정보연구
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• 제14권3호
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• pp.159-183
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• 2012

본 연구에서는 우리나라 각 지방자치단체 등지에서 추진하고 있는 외국인직접투자 유치 정책에 기초 정보를 제공한다. 변이-비중 모형(Shift-Share Model)을 이용해 외국인직접투자 유치 실적의 증감 요인은 지역별 각 산업의 분해 요인에 따라 구조적 특징을 파악함으로써 찾을 수 있다. 분석은 2009년을 기준으로 2010년, 2011년 전국(수도권과 비수도권으로 구분)의 외국인직접투자 실적을 비교, 전산업(한국표준산업분류 중분류)에 대해 실시했다. 그 결과는 국가성장효과(NS), 산업구조효과(IM), 지역할당효과(RS)로 구분하여 외국인직접투자 증감요인을 살펴보면 2010년과 2011년 수도권, 비수도권 모두에서 국가성장효과(NS)는 음(-)의 값을 갖고 있었다. 이는 세계경기침체의 여파가 국내 경제에 미치는 영향이 큰 것으로 나타났기 때문인 것으로 분석된다. 산업구조효과(IM)의 경우 수도권은 교육, 문화, 비즈니스 및 교통 등의 발달로 비수도권에 비해 서비스 산업의 발달에 유효한 환경을 가지고 있다. 특히 서비스(음식숙박, 비즈니스서비스업, 문화오락) 부문에서 그 특징을 찾을 수 있었다. 비수도권은 제조업(비금속광물, 전기전자) 등의 부문에서 산업발달의 전후방 연계효과 및 지역적 특징이 큰 역할을 한 것으로 분석된다. 그러나 지역할당효과(RS)에서는 수도권에서 제조업 분야의 금속 및 화공분야에서 경쟁력이 있는 것으로 도출되었다.

• 한국산업융합학회 논문집
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• 제25권6_3호
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• pp.1207-1219
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• 2022

「Act On Contracts To Which The State Is A Party」 stipulates that the "Construction Standard Production Rate" and "Construction Standard Unit Price" be used as the criteria for determining the estimated price of construction works performed by public institutions. In this regard, issues such as the application scope of the Construction Standard Unit Price, and the effect of budget reduction continue. However, due to the lack of quantitative data on the actual application of Construction Standard Unit Price, it is difficult to objectively evaluate various issues. In order to prepare data for objective evaluation of the Construction Standard Unit Price, this study analyzed the ripple effect of applying the Construction Standard Unit Price based on the bill of quantity. As a result of the analysis, the Construction Standard Unit Price ripple effect in the civil engineering part was 9.2%, and it was analyzed that there was a ripple effect of about 1.9% based on the civil engineering direct cost. In the construction part, the ripple effect was analyzed to be relatively high at 17%, but it was found to have a ripple effect of about 3% in the construction direct cost. Based on the total direct cost, the ripple effect was calculated as 2.2%. Based on the analysis results, it is possible to evaluate the effect of applying the Standard Market Unit Price, and it is expected to be used as basic data to solve issues. As a future study, it is necessary to additionally analyze the ripple effect by Standard Market Unit Price application range (over 10 billion, over 20 billion won, etc.) and delivery system type (comprehensive evaluation, qualification examination, technical bidding, etc.). In addition, it is necessary to study the appropriate ripple effect of the Standard Market Unit Price.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권8호
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• pp.514-521
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• 2000

This paper presents a direct thrust control scheme for permanent magnet linear synchronous motor(PMLSM) by using digital signal processor(DSP). And a simulation method for the direct thrust control of a permanent magnet linear synchronous motor using the equivalent circuit is presented. The detent force that was obtained by cubic spline method is considered in the simulation. Thrust correction coefficient is utilized to estimate actual thrust on the direct thrust control, which considers the longitudinal end effect due to the finite core length of the permanent magnet linear synchronous motor. The motor self inductance, the initial flux linkage by the permanent magnet is calculated in advance by the finite element analysis, and then the direct control simulation is carried out. As the results, thrust, current and speed are shwon.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1124-1136
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• 2017

Direct Power Control technique has become popular in the grid connected Voltage Source Converter (VSC) applications due to its simplicity, direct voltage vector selection and improved dynamic performance. In this paper, a direct method to determine the effect of voltage vector on the instantaneous active and reactive power variations is developed. An alternative Look Up Table is proposed which minimizes the commutations in the converter and results in minimum reactive power variation. The application of suggested table is established for Shunt Active Power Filter (SAPF) application. The Predictive Direct Power Control method, which minimizes apparent power variation, is further investigated to reduce commutations in converters. Both the methods are validated using 2 kVA laboratory prototype of Shunt Active Power Filters (SAPF).

• 태양에너지
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• 제9권3호
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• pp.13-24
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• 1989

Direct and diffuse components of solar radiation were measured inside and outside a single-span plastic greenhouse. To analyze the direct solar radiation inside the plastic greenhouse, the cross-section of the greenhouse was assumed to be circular. Then the direct solar radiation transmitted into the greenhouse was calculated theoretically, and compared with the experimental measurements. The results are summarized as follows: (1) The transmissivities of total solar radiation were about 65% on cloudy days and 50% on clear days. For cloudy days, the transmissivity of the total solar radiation was regarded as the transmissivity of sky diffuse radiation. (2) The ratio of the inside effective scattered component of direct solar radiation to the diffuse radiation was 60-65%. (3) It appeared that the seasonal variation of the transmissivity of total solar radiation was adversely affected by the transmissivity of direct solar radiation and the effective scattered coefficient. But the effect of the transmissivity of direct solar radiation was dominant factor. (4) Computer simulation showed that the inside direct solar radiation was decreased as the floor of the plastic greenhouse was higher. (5) The predicted value of the inside direct solar radiation was 3.3% to 29.0% higher than the measured value.

• 동서간호학연구지
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• 제29권2호
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• pp.150-160
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• 2023

This study aimed to identify the actor and partner effects of parenting efficacy, spousal support on parenting stress and depression in couples with children with attention deficit hyperactivity disorder (ADHD). Methods: A cross-sectional survey design was used. Participants were 103 couples (103 husbands, 103 wives) with children with ADHD visiting child adolescent psychiatry clinic or community mental health center in Seoul, Gyeonggi-do, South Korea. Data were analyzed by SPSS 20.0 and AMOS 20.0 program. Results: The parenting efficacy of husbands and wives had direct actor effect (β=-.69, p=.004; β=-.60, p=.004) and partner effect (β=-.22, p=.007; β=-.18, p=.026) on their parenting stress. In addition, husbands and wives's parenting efficacy had a direct actor effect (β=-.25, p=.031; β=-.21, p=.025) on their depression and indirect actor effect (β=-.25, p=.004; β=-.34, p=.004) through parenting stress on their depression. However, parenting stress did not show a partner effect on depression. Husband and wife's parenting efficacy had a direct effect (β=.46, p=.004; β=.25, p=.009) on perceived spousal support. The effects of husbands and wives were the same in actor effect size (χ² differences=0.74, p=.390) and partner effect size (χ² differences=0.20, p=.652) of parenting efficacy on parenting stress. In addition, the effect sizes of husbands and wives were the same in actor effect size (χ² differences=0.93, p=.334) and partner effect size (χ² differences=0.15, p=.704) for parenting stress and depression. Conclusion: The results of this study may provide the foundation for developing a nursing intervention program that can maximize interaction between couples with ADHD children.

• 한국생활과학회지
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• 제21권5호
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• pp.915-927
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• 2012

The purpose of this study was to examine the mediation effect of peer attachment on the relationship between children's depression and mother attachment. The respondents in this study were 697 school aged children attending elementary schools in Daegu and Gyeongbuk Province. Questionnaires, which required self-reporting by children, were used to investigate mother attachment, peer attachment and depression. The collected data were analyzed by Structural Equation Modeling(SEM) and Sobel test using AMOS 8.0, and SPSS 15.0. The results of the study were as follows. Structural Equation Modeling(SEM) revealed that peer attachment partially mediated the relationship between mother attachment and depression. First, mother attachment had a direct effect on peer attachment. Second, peer attachment had a direct effect on depression. Third, mother attachment had an indirect effect on depression as a mediated effect of peer attachment.