• Title/Summary/Keyword: Model Validity

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Validation of the Need for Closure Scale-Short Form (단축형 종결 욕구의 타당화)

  • Kim, Eunkyung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.10
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    • pp.166-173
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    • 2020
  • The purpose of the present study was to validate the Need for Closure Scale-Short Form (NFCS-SF), which measures the need for cognitive closure. Participants completed questionnaires regarding need for cognitive closure, intolerance of uncertainty, depression, and anxiety. Of the 536 data collected between May and July 2017, data from a total of 495 participants were analyzed using SPSS 20.0 and M-Plus. The results of the study are as follows. First, a 15-item selection comprised three items from each facet scale via exploratory factor analysis. Second, the NFCS-SF demonstrated good internal consistency (Study 1, Cronbach's α=.85; Study 2, Cronbach's α=.84). Third, the results of the confirmatory factor analyses supported a 5-factor model (χ2(80)=178.34, p<.001; CFI=.87, TLI=.83, RMSEA=.07, SRMR=.08). Fourth, the NFCS-SF showed significant correlation with the measures of intolerance of uncertainty (r=.58, p<.01), depression (r=.16, p<.05), and anxiety (state anxiety, r=.31, p<.01; trait anxiety, r=.29, as well as the NFCS (r=.86, p<.01). Based on these findings, significance and limitations of the results as well as suggestions for further study are discussed.

A study on 3-D indoor localization based on visible-light communication considering the inclination and azimuth of the receiver (수신기의 기울기 및 방위를 고려한 가시광 통신기반 3차원 실내 위치인식에 대한 연구)

  • Kim, Won-Yeol;Zin, Hyeon-Cheol;Kim, Jong-Chan;Noh, Duck-Soo;Seo, Dong-Hoan
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.7
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    • pp.647-654
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    • 2016
  • Indoor localization based on visible-light communication using the received signal strength intensity (RSSI) has been widely studied because of its high accuracy compared with other wireless localization methods. However, because the RSSI can vary according to the inclination and azimuth of the receiver, a large error can occur, even at the same position. In this paper, we propose a visible-light communication-based 3-D indoor positioning algorithm using the Gauss-Newton technique in order to reduce the errors caused by the change in the inclination of the receiver. The proposed system reduces the amount of computations by selecting the initial position of the receiver through the linear least-squares method (LSM), which is applied to the RSSIs, and improves the position accuracy by applying the Gauss-Newton technique to the 3-D nonlinear model that contains the RSSIs acquired by the changes in the azimuth and inclination of the receiver. In order to verify the validity of the proposed algorithm in an indoor space with dimensions of $6{\times}6{\times}3m$ where 16 LED lights are installed, we compare and analyze the errors of the conventional linear LSM-based trilateration technique and the proposed algorithm according to the changes in the inclination and azimuth of the receiver. The experimental results show that the location accuracy of the proposed algorithm is improved by 82.5% compared to the conventional LSM-based trilateration technique.

A Study on the Optimization of Heat Flux in Engine Room of Auxiliary Power Unit for Self-Propelled Artillery (자주포용 보조동력장치 엔진룸의 열유동 최적화에 관한 연구)

  • Noh, Sang Wan;Park, Young Min;Kim, Sung Hoon;Lee, Jae Dong;Kim, Byung Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.12
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    • pp.629-635
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    • 2019
  • In this study, we analyzed the effect of FAN and oil cooler application on APU. MIL-STD-810 was applied to the atmospheric environment and radiation dose in order to perform thermal flow analysis. The heat flow was analyzed for the case in which the inlet / outlet fan was applied (Case 1), the case in which the inlet fan and the oil cooler were applied (Case 2), and the case in which the inlet / outlet fan and the oil cooler were applied (Case 3). As a result, it was confirmed that the cylinder head temperature of Case 3 was 21.4 times lower than that of Case 1 and 8.0 times lower than that of Case 2. Experiments were conducted under the same ambient conditions in order to examine the validity of the results. The numerical values and experimental results showed a difference of less than 7%. Through this, we were able to confirm that the APU heat flow optimization model satisfies the design conditions. The results of this study are expected to be used as basic data for optimizing heat flow of APU.

A Study on the Simulation Modeling Method of LKAS Test Evalution (LKAS 시험평가의 시뮬레이션 모델링 기법에 관한 연구)

  • Bae, Geon-Hwan;Lee, Seon-bong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.3
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    • pp.57-64
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    • 2020
  • The leading technologies of the ADAS (Advanced Driver Assist System) are ACC (Advanced Cruise Control), LKAS (Lane Keeping Assist System), and AEB (Autonomous Emergency Braking). LKAS is a system that uses cameras and infrared sensors to control steering and return to its running lane in the event of unintentional deviations. The actual test is performed for a safety evaluation and verification of the system. On the other hand, research on the system evaluation method is insufficient when an additional steering angle is applied. In this study, a model using Prescan was developed and simulated for the scenarios proposed in the preceding study. Comparative analyses of the simulation and the actual test were performed. As a result, the modeling validity was verified. A difference between the front wheels and the lane occurred due to the return velocity. The results revealed a maximum error of 0.56 m. The error occurred because the lateral velocity of the car was relatively small. On the other hand, the distance from wheels to the lanes displayed a tendency of approximately 0.5 m. This can be verified reliably.

A latent profile analysis of job performance types based on task performance, contextual performance and counterproductive work behavior (과업수행, 맥락수행, 반생산적 업무행동 기반의 직무수행 유형 분석: 잠재프로파일분석을 중심으로)

  • Yoo, Young-Sam;Kim, Myoung-So;Noh, So-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.4
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    • pp.145-155
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    • 2020
  • Since Campbell (1990) proposed multidimensionality of job performance, unlike the single structure of traditional job performance, it has been largely classified as task performance, contextual performance, and counterproductive work behavior. The objective of this study is to validate the threecriteria currently considered major aspects of job performance, to identify different types of performance based on three dimensions, and to compare the power of personality factors among performance types. A total of 681 employees working at various organizations participated in an on-line survey. The survey included boththe exploratory and confirmatory factor analyses. A 3-factor job performance model consisting of three dimensions was also included. The relationships between performance dimensions and personality factors differedby dimensions of performance, supporting the validity of the 3-factor structure of performance.The results of the Latent Profile Analysis identified four types of performance: exemplary, moderately conscientious moderate, and conscientious, butlow.. The Multinomial logistic regression analysis showed each type differed significantly according to the predictors of personality variables. In conclusion, implications and limitations of the study were noted.

Optimization for the Post-Harvest Induction of trans-Resveratrol by Soaking Treatment in Raw Peanuts (침지조작에 의한 레스베라트롤 증가조건의 최적화)

  • Lee, Seon-Sook;Seo, Sun-Jung;Lee, Boo-Yong;Lee, Hee-Bong;Lee, Junsoo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.4
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    • pp.567-571
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    • 2005
  • In this study, the effects of varying the amount of water, soaking time at $25^{\circ}C$ and drying time after soaking at $45^{\circ}C$ on the induction of resveratrol were evaluated to optimize the soaking treatment by response surface methodology (RSM). After response surface regression (RSREG), the second-order polynomial equation was fitted to the experimental data. The analysis of variance showed that the model appeared to be adequate $(R^2=0.9547)$ with no significant lack of fit (p>0.1). From statistical analysis, amount of water and soaking time were found to be significant factors. On the other hand, drying time was not significant. Ridge analysis showed that the optimized parameters were $67.15\%$ for amount of water, 19.58 hr for soaking time, 65.56 hr for drying time. It was confirmed that resveratrol content was increased from $0.1\;{\mu}g/g$ to $4.55\;{\mu}g/g$ under the optimized conditions. In addition, the experimental values at the optimized condition agreed with values predicted by ridge analysis. The analytical method validation parameters such as accuracy, precision, and specificity were calculated to ensure the method's validity.

A Study on the Growth Proccess and Strategic Niche Management of New Energy Technology: A Case Study with Government Supporting Photovoltaic R&D Project (전략적 니치관리(SNM)를 활용한 정부 신재생 R&D 성장과정 분석)

  • Kim, Bong-Gyun;Moon, Sun-Woo
    • Journal of Technology Innovation
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    • v.20 no.2
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    • pp.161-187
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    • 2012
  • Recently, environmentally friendly technology are becoming important due to reconsideration about climate change and environmental pollution. In addition, as well as technical skills and social interaction through an analysis of the nonlinear transition management and policy implementation are emerging. This study of the development of photovoltaic industry in Korea 10 years analyze with strategic niche management (SNM) based on the theoretical and multi-layered perspective (MLP) is used as the analytical framework. Choose the gerverment-support project for niche technology, through a process of quantifying and alnalyze the phase transition to Regime with the numerical method and policy vision, learning effects, and network that key elements of SNM, MLP. Through the analysis of the photovoltaic industry technology-commercialization phase was investigated. This conventional overall and step-by-step model for technical management is proposed to replace exiting linear and narrow method and through the case study its validity was confirmed.

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Development of a Korean Version of an Advance Directive Model via Cognitive Interview (인지면담을 이용한 한국형 사전의료의향서 모델 개발)

  • Kim, Shin Mi;Hong, Young Sun;Hong, Sun Woo;Kim, Jin Shil;Kim, Ki Sook
    • Journal of Hospice and Palliative Care
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    • v.16 no.1
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    • pp.20-32
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    • 2013
  • Purpose: The purpose of the study was to develop a feasible form of a Korean version of advance directives (K-AD). Methods: Sixteen adults participated in this study: 10 aged 20~50 years and nine aged 65 years or older. Using a draft version of the K-AD, cognitive interview was conducted on the participants to establish a culturally acceptable form of advance directives whose directions can be understood and responded accordingly by the general population. Results: Cognitive interviews revealed areas of concerns for the draft version of K-AD: lack of instructions or clarity for technical and medical terms, context complexity and inadequate response categories. The draft version was revised by rewording, offering examples and rearranging the context. Editorial style was added with appropriate uses of bold fonts, bullet-points and underlines to facilitate interviewees' cognitive responses. Conclusion: Study results feasibility of the revised version of the K-AD. Further study should be performed with a larger number of participants to develop a K-AD with an acceptable level of reliability and validity.

Estimation of Longitudinal Dynamic Stability Derivatives for a Tailless Aircraft Using Dynamic Mesh Method (Dynamic Mesh 기법을 활용한 무미익 비행체 종축 동안정 미계수 예측)

  • Chung, Hyoung-Seog;Yang, Kwang-Jin;Kwon, Ky-Beom;Lee, Ho-Keun;Kim, Sun-Tae;Lee, Myung-Sup;Reu, Taekyu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.43 no.3
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    • pp.232-242
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    • 2015
  • For stealth performance consideration, many UAV designs are adopting tailless lambda-shaped configurations which are likely to have unsteady dynamic characteristics. In order to control such UAVs through automatic flight control system, more accurate estimation of dynamic stability derivatives becomes essential. In this paper, dynamic stability derivatives of a tailless lambda-shaped UAV are estimated through numerically simulated forced oscillation method incorporating dynamic mesh technique. First, the methodology is validated by benchmarking the CFD results against previously published experimental results of the Standard Dynamics Model(SDM). The dependency of initial angle of attack, oscillation frequency and oscillation magnitude on the dynamic stability derivatives of a tailless UAV configuration is then studied. The results show reasonable agreements with experimental reference data and prove the validity and efficiency of the concept of using CFD to estimate the dynamic derivatives.

Rethinking OTT regulation based on the global OTT market trends and regulation cases (OTT 서비스의 유형과 주요국의 규제 정책에 대한 고찰)

  • Kim, Suwon;Kim, Daewon
    • Journal of Internet Computing and Services
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    • v.20 no.6
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    • pp.143-156
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    • 2019
  • Discussion on OTT regulation has become fiercer, as OTT services' impacts on the global and domestic media market have been exponentially growing. In South Korea, it is argued that, on the basis of the similarity between television program and OTT's video content, OTT needs to be regulated in order to protect fair competition and to control sociocultural effects. In many of the discussions, developed countries' cases have been used for supporting OTT regulation. In this paper, we first analyzed the global OTT market trends based on our own categorization of OTT services. then we assessed the validity of the application of the foreign cases in the current OTT regulation debates in Korea. We proposed six OTT types (aggregation, mediation, mediation-aggregation, multi-screen, outlet, and outlet-linear) simultaneously considering service operator' origin, business model, content format, and content delivery. These services have been consistently evolving, and the OTT market has been increasingly competitive especially around content differentiation. Regulators must be wary of hastily introducing competition regulation to the dynamically innovating OTT market. The foreign cases, including the US, EU, the UK, and Japan, hardly seem to be appropriate bases for strengthening OTT regulation. Rather, they were focused more on promoting competition in the domestic media market and enriching the content ecosystem. Therefore, we need to consider revision of the outdated media regulation frameworks instead of fitting OTT under them, and to recognize the priority of securing practical jurisdiction on global service providers before capturing local players into the conventional regulation systems.