• Title/Summary/Keyword: scale-model

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IMPLEMENTATION OF TRL TOOLS TO KOREAN NATIONAL CONSTRUCTION AND TRANSPORTATION R&D PROJECTS FOR IMPROVING PRACTICAL USE

  • Namgyun Kim;Byungho An;Jaehong Choi;Hyunseok Lee;Sanghyuk Park;Yeasang Kim
    • International conference on construction engineering and project management
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    • 2013.01a
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    • pp.608-615
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    • 2013
  • The major countries including Korea extend the national investment on R&D and implement the business performance diffusion policy as the knowledge based competition age arrives recently. The necessity for risk management and systematic management system for R&D achievement have been appeared to prevent the failure as the R&D scale becomes larger as it was said. For this matter, the organization such as NASA and DoD in USA defines the Technology Readiness Level (TRL) as a quantitative accomplishment management index and utilize the Technology Readiness Assessment (TRA) system as a criterion. Such tool is evaluated as very effective in the R&D project purposed the practicalization. It is expected that the disadvantage of evaluation system which is oriented to the academic accomplishment in its contents of current research and to contribute greatly to the practicalization of outcomes when such technology readiness level concept is applied to Korean national construction and transportation R&D project. Accordingly, this study analyzed the concept of TRL·TRA, the characteristics and current evaluation management system of Korean national construction and transportation R&D project and suggested the construction and transportation R&D project TRL·TRA performance model to accomplish the practicalization purpose.

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Economic Feasibility Analysis of Electrical Vehicle Charging Station Connected with PV & ESS based on ESS Valuation (ESS 가치평가 기반 PV-ESS 연계 EV 충전스테이션 사업 타당성 분석)

  • Ji Hyun Lee;Seong Jegarl;Yong Chan Jung;Ah-Yun Yoon
    • Current Photovoltaic Research
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    • v.11 no.4
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    • pp.124-133
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    • 2023
  • In order to deploy the large-scale energy storage (ES) service in the various industry, it is very important to develop a business model with high technological and economic feasibility through detailed valuation of cost and expected benefits. In relation to this, this paper established an optimal scheduling plan for electric vehicle charging stations connected with photovoltaic (PV) and ES technologies in Korea using the distributed energy resource valuation tool and analyzed the feasibility of the project. In addition, the impact of incentives such as REC (Renewable Energy Certificate) to be given to electric vehicle charging stations in accordance with the relevant laws to be revised in the future was analyzed. As a results, the methodology presented in this paper are expected to be used in various ways to analyze the feasibility of various business models linked to renewable energy and ES technologies as well as the electric vehicle market.

Corporate Governance and Long-term Corporate Survival in an Emerging Economy (신흥국 기업의 지배구조와 기업의 장기 생존)

  • Jang-Hoon Kim;Se-Yeon Ahn
    • Korea Trade Review
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    • v.46 no.3
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    • pp.65-79
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    • 2021
  • This paper investigates how corporate governance characteristics are related to long-term corporate survival in an emerging economy. We used the data of 311 companies listed on the Korean Stock Exchange (KSE) in 1979 and examined the survival chances of those companies through the IMF crisis in 1998, upon governance characteristics that are expected to increase long-term strategic orientations. We utilized Cox regression model for the analysis. The results indicate that firms with particular governance characteristics that may be tied to CEO's long-term orientations show higher long-term survivability. Specifically, the probability of a firm's long-term survival is increased when founding family ownership is sustained, the company ownership is concentrated, and the CEO is the largest shareholder. This study has significance in that it is one of initial tries to examine the impact of corporate governance on long-term corporate survival with large scale statistical analysis. Also, the study findings provide some clues as to why the portion of family firms in emerging economies is continuously increased, thus providing meaningful insights to corporate governance literature.

Navigating the Transformative Landscape of Virtual Education Trends across India

  • Asha SHARMA;Aditya MISHRA
    • Fourth Industrial Review
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    • v.4 no.1
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    • pp.1-9
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    • 2024
  • Purpose: Education is the part of a fundamental human right across the world. In recent years, the trend of virtual education has increased tremendously. The paper aims to find the impact of adoption, accessibility, interactions, knowledge, and satisfaction on the success of transformation towards virtual education. Research design, data and methodology: Primary data has been gathered through the use of responses from students taking admission in virtual higher education to standardized questionnaires. Of the 250, only 122 were considered complete and have been used in further studies. Convinced random sampling method has been used. The results were evaluated using the Likert Five-Point Scale. For applying these statistical tools software SmartPLS and SPSS 19 have been used. The fitness of the model has been re-checked through an Artificial Neural Network (ANN). Result: Results derived that adoption, accessibility, and interactions have a significant impact on knowledge, knowledge influences satisfaction level and satisfaction have a meaningful impact on the success of transformation towards virtual education. Conclusion: It can be concluded that virtual education has the potential to change the future of the education system and its potential in India. The highest importance is due to satisfaction (100%), adoption (98.7%), knowledge (91.4%), accessibility (62%), and interaction (29.2%).

The Effects of Stress Vulnerability and Parental Burnout on Mental Health in Women with Early School-Age Children during the COVID-19 Pandemic: Mediating Effect of Spirituality (COVID-19 팬데믹 기간 중 학령초기 자녀를 가진 여성의 스트레스 취약성, 부모소진이 정신건강에 미치는 영향: 영성의 매개효과)

  • Yeom, Mijung;Kwon, Min
    • Journal of Korean Academy of Nursing
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    • v.54 no.1
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    • pp.106-117
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    • 2024
  • Purpose: This study examined the effects of stress vulnerability and parental burnout on the mental health of women with early school-aged children, with a focus on the mediating role of spirituality. Methods: A survey was conducted among 171 women with early schoolaged children in Gyeonggi Province, Gangwon Province, and Seoul. Data were collected from September to December 2022 using the Korean-Symptom Check List 95, the Parental Burnout Assessment, and the Spirituality Assessment Scale. The data were analyzed using structural equation modeling with SPSS/WIN 22.0 and AMOS 20.0. Results: The study model demonstrated a good fit, explaining 40.5% of the variance in mental health through stress vulnerability, parental burnout, and spirituality. Spirituality had a significant direct impact on mental health. Additionally, participants' spirituality directly influenced their mental health, while stress vulnerability and parental burnout indirectly affected their mental health and were mediated through spirituality. Conclusion: Stress vulnerability and parental burnout are negatively associated with mental health, while spirituality partially mediates these effects. Implementing a program to promote spirituality is suggested to assist mothers in recognizing the value and meaning of parenting activities during nursing interventions for mental health.

Standardized multi-institutional data analysis of fixed and removable prosthesis: estimation of life expectancy with regards to variable risk factors

  • Hae-In Jeon;Joon-Ho Yoon;Jeong Hoon Kim;Dong-Wook Kim;Namsik Oh;Young-Bum Park
    • The Journal of Advanced Prosthodontics
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    • v.16 no.2
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    • pp.67-76
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    • 2024
  • PURPOSE. This study aims to assess and predict lifespan of dental prostheses using newly developed Korean Association of Prosthodontics (KAP) criteria through a large-scale, multi-institutional survey. MATERIALS AND METHODS. Survey was conducted including 16 institutions. Cox proportional hazards model and principal component analysis (PCA) were used to find out relevant factors and predict life expectancy. RESULTS. 1,703 fixed and 815 removable prostheses data were collected and evaluated. Statistically significant factors in fixed prosthesis failure were plaque index and material type, with a median survival of 10 to 18 years and 14 to 20 years each. In removable prosthesis, factors were national health insurance coverage, antagonist type, and prosthesis type (complete or partial denture), with median survival of 10 to 13 years, 11 to 14 years, and 10 to 15 years each. For still-usable prostheses, PCA analysis predicted an additional 3 years in fixed and 4.8 years in removable prosthesis. CONCLUSION. Life expectancy of a prosthesis differed significantly by factors mostly controllable either by dentist or a patient. Overall life expectancy was shown to be longer than previous research.

Optimal location of a single through-bolt for efficient strengthening of CHS K-joints

  • Amr Fayed;Ali Hammad;Amr Shaat
    • Structural Engineering and Mechanics
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    • v.89 no.1
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    • pp.61-75
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    • 2024
  • Strengthening of hollow structural sections using through-bolts is a cost-effective and straightforward approach. It's a versatile method that can be applied during both design and service phases, serving as a non-disruptive and budget-friendly retrofitting solution. Existing research on axially loaded hollow sections T-joints has demonstrated that this technique can amplify the joint strength by 50%, where single bolt could enhance the strength of the joint by 35%. However, there's a gap in understanding their use for K-joints. As the behavior of K-joints is more complex, and they are widely existent in structures, this study aims to bridge that gap by conducting comprehensive parametric study using finite element analysis. Numerical investigation was conducted to evaluate the effect of through bolts on K-joints focusing on using single through bolt to achieve most of the strengthening effect. A full-scale parametric model was developed to investigate the effect of various geometric parameters of the joint. This study concluded the existence of optimal bolt location to achieve the highest strength gain for the joint. Moreover, a rigorous statistical analysis was conducted on the data to propose design equations to predict optimal bolt location and the corresponding strength gain implementing the verified by finite element models.

Numerical approach to predict stress-strain model for tie confined self curing self compacting concrete (TCSCSCC)

  • P Swamy Naga Ratna Giri;Vikram Tati;Rathish Kumar P;Rajesh Kumar G
    • Computers and Concrete
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    • v.33 no.2
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    • pp.205-216
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    • 2024
  • Self-Curing Self Compacting Concrete (SCSCC), is a special concrete in contemporary construction practice aimed at enhancing the performance of structural concrete. Its primary function is to ensure a sufficient moisture supply that facilitates hydration along with flow, particularly in the context of high-rise buildings and tall structures. This innovative concrete addresses the challenges of maintaining adequate curing conditions in large-scale projects, maintaining requisite workability, contributing to the overall durability and longevity of concrete structures. For implementing such a versatile material in construction, it is imperative to understand the stress-strain (S-S) behaviour. The primary aim of this study is to develop the S-S curves for TCSCSCC and compare through experimental results. Finite element (FE) analysis based ATENA-GiD was employed for the numerical simulation and develop the analytical stress-strain curves by introducing parameters viz., grade of concrete, tie diameter, tie spacing and yield strength. The stress ratio and the strain ratios are evaluated and compared with experimental values. The mean error is 1.2% with respect to stresses and 2.2% in case of strain. Finally, the stress block parameters for tie confined SCSCC are evaluated and equations are proposed for the same in terms of confinement index.

Particle filter approach for extracting the non-linear aerodynamic damping of a cable-stayed bridge subjected to crosswind action

  • Aljaboobi Mohammed;Shi-Xiong Zheng;Al-Sebaeai Maged
    • Wind and Structures
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    • v.38 no.2
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    • pp.119-128
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    • 2024
  • The aerodynamic damping is an essential factor that can considerably affect the dynamic response of the cable-stayed bridge induced by crosswind load. However, developing an accurate and efficient aerodynamic damping model is crucial for evaluating the crosswind load-induced response on cable-stayed bridges. Therefore, this study proposes a new method for identifying aerodynamic damping of the bridge structures under crosswind load using an extended Kalman filter (EKF) and the particle filter (PF) algorithm. The EKF algorithm is introduced to capture the aerodynamic damping ratio. PF technique is used to select the optimal spectral representation of the noise. The effectiveness and accuracy of the proposed solution were investigated through full-scale vibration measurement data of the crosswind-induced on the bridge's girder. The results show that the proposed solution can generate an efficient and robust estimation. The errors between the target and extracted values are around 0.01mm and 0.003^o, respectively, for the vertical and torsional motion. The relationship between the amplitude and the aerodynamic damping ratio is linear for small reduced wind velocity and nonlinear with the increasing value of the reduced wind velocity. Finally, the results show the influence of the level of noise.

Development of scaling approach based on experimental and CFD data for thermal stratification and mixing induced by steam injection through spargers

  • Xicheng Wang;Dmitry Grishchenko;Pavel Kudinov
    • Nuclear Engineering and Technology
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    • v.56 no.3
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    • pp.1052-1065
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    • 2024
  • Advanced Pressurized Water Reactors (APWRs) and Boiling Water Reactors (BWRs) employ a suppression pool as a heat sink to prevent containment overpressure. Steam can be discharged into the pool through multi-hole spargers or blowdown pipes in both normal and accident conditions. Direct Contact Condensation (DCC) creates sources of momentum and heat. The competition between these two sources determines the development of thermal stratification or mixing of the pool. Thermal stratification is of safety concern as it reduces the cooling capability compared to a completely mixed pool condition. In this work we develop a scaling approach to prediction of the thermal stratification in a water pool induced by steam injection through spargers. Experimental data obtained from large-scale pool tests conducted in the PPOOLEX and PANDA facilities, as well as simulation results obtained using validated codes are used to develop the scaling. Two injection orientations, namely radial injection through multi-hole Sparger Head (SH) and vertical injection through Load Reduction Ring (LRR), are considered. We show that the erosion rate of the cold layer can be estimated using the Richardson number. In this work, scaling laws are proposed to estimate both the (i) transient erosion velocity and (ii) the stable position of the thermocline. These scaling laws are then implemented into a 1D model to simulate the thermal behavior of the pool during steam injection through the sparger.