• 제목/요약/키워드: breaking point

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Numerical Model for Cross-Shore Sediment Transport (해안선 횡방향의 표사이동 예측모형)

  • 이철응;김무현
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • 제7권1호
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    • pp.57-69
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    • 1995
  • The development of a finite difference model for cross-shore sediment transport prediction in the surf tone due to the storm surge event is presented in this paper. Using the inhomogeneous diffusion equation with moving boundaries. the present numerical model is found to be robust and efficient and does not possess a number of restrictions imposed in Kriebel and Dean's(1985) numerical model. Our numerical model is validated through comparison with the analytical solution. the data of a large-scale experiment and the field data of Hurricane Eloise. The Present model if able to predict the averaged volumetric erosion rate of a beach due to the time-varying real storm surge hydrographs and satisfies the conservation of sediment between eroded volume in the onshore region and deposited volume in the offshore region. In addition. the present model is able to reasonably predict the recession of a beach with wide berm and dune. and can describe the change of a breaking point by the offshore deposition. From the sensitivity analysis or the present numerical model with various input parameters, it is concluded that the present numerical model is able to analyze the beach change in a reliable manner including the effects of different sizes of sediments.

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Numerical Simulation of Beach Profile Changes (해빈 종단면 변형의 수치모의)

  • Cheon, Se-Hyeon;Ahn, Kyung-Mo
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • 제20권1호
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    • pp.101-109
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    • 2008
  • Several numerical models for predicting beach profile changes have been developed by many researchers. Many of the earlier models are known to simulate the erosional profiles with the formation of offshore bar. However, most of the models don't have proper mechanism to incorporate the recovery process of the eroded profiles after a storm and can not simulate the beach accretion with acceptable accuracy. In order to overcome these shortcomings, we propose a new numerical model which has new features to simulate the accretional phase of beach recovery process after storm including such as redistribution of suspended sand particles near the breaking point. The simulation results of the proposed model were compared with LWT (Large Wave Tank) experiments performed at CRIEPI (Central Research Institute of Electric Power Industry in Japan) and CE (the Us Army Corps of Engineers) and it was shown to have performed better compared to SBEACH (Storm-induced BEAch CHange).

Case Study for Preventing Construction Site Fall Accidents (건설현장 추락사고 예방을 위한 사례 연구)

  • Choi, Du Ho
    • Korean Journal of Construction Engineering and Management
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    • 제20권6호
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    • pp.81-88
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    • 2019
  • Recently, the government has shown a decrease in disaster accidents throughout the industry and construction industry due to various efforts to reduce disasters. However, the fall accidents in the construction industry are not decreasing but increasing. In particular, the fall accident caused by scaffolding is low each year, but the disaster intensity is very high in that it directly leads to the death of workers. Scaffolding working environment in domestic construction industry is very poor. Moreover, scaffold workers in small construction sites are not subject to safety oversight and control. Therefore, this study is the installation and non-installation of the vertical lifeline, which is the most fundamental problem to be prevented during the study, to prevent the fall of the moon scaffold. In addition, it is hoped that it will be a solution for preventing accidents in construction site construction through the identification of various causes of disasters such as rope loosening, rope breaking, and fixed point failure.

A Study on the hacking countermeasures in Military security (군보안상 해킹대응방안에 관한 연구)

  • Kim, Doo Hwan;Park, Ho Jeong
    • Convergence Security Journal
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    • 제17권5호
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    • pp.133-142
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    • 2017
  • Breaking away from the blind faith of internal military security network, current military security demands strengthening measure on the H/W, controlling measure against information communications within the military, strengthening measure on the linkage point of the military and universal internal networks, legal supplementation, sucurity management ofn the military facilities from outsourcing services supporting the military. By analyzing the danger of military organizations hacking and real hacking cases, policy establishment for strengthening the security on military network hacking, legal supplementation and controlling measure for the outsourcing services are the pragmatic counter measures against military security hacking considering the peculiarities of military rather than the application of physical containment linked with information communications technology on the H/W safety measures.

Wind Speed Reduction Efficiency of Potenga-Muhuri Irrigation Project Coastal Belt in Chittagong, Bangladesh

  • Kader, Mohammad Abdul;Hossain, Mohammed Kamal;Kabir, Md. Humayain
    • Journal of Forest and Environmental Science
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    • 제35권2호
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    • pp.78-89
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    • 2019
  • Coastal plantation is one of the key natural defence against the tidal surge induced tropical cyclones. In Bangladesh, a total of 81 km long coastal belt was established from Potenga to Muhuri in Chittagong. This study explores the wind protection efficiency of the coastal plantations at 28 observation points along the 81 km long Potenga-Muhuri irrigation project of Chittagong coastal belt. We found that wind protection efficiency was lowest (1.40% and 7.00%) at $1^{st}$ observation point of outside the embankment (OE) and inside of the embankment (IE) than Sea Shore (SS), respectively. On the other hand, the highest (82.89% and 95.72%) wind protection efficiency was observed at $22^{th}$ observation for Outside of the Embankment (OE) and Inside of the Embankment (IE) than Sea Shore (SS), respectively. This study also highlighted on species specific wind protection efficiency. The result revealed that 6-year old Casuarina, 6-year old mixed plantation and 10-year old Sonneretia apetala with the width of 20.12 m, 30.48 m, and 15.24 m can reduce wind speed up to 30 H, 30 H and 25 H at windward side, respectively. Analysis also showed that percentage of wind reduction was significantly higher at plantation coast than barren, and ship breaking yard coast. The findings of this study have great potentiality to contribute substantially to take more coastal embankment afforestation programs by the Government of Bangladesh and to choose the more wind resistant plant species throughout the coastal areas of the country.

A Study on the Establishment of Yeongbojeong in Boryeong (보령 영보정 창건에 관한 연구)

  • Kim, Myung-Rae
    • Journal of the Architectural Institute of Korea Planning & Design
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    • 제35권2호
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    • pp.105-114
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    • 2019
  • Yeongbojeong was a famous pavilion of Joseon, which was located in Chungcheong-Suyeong, Ocheon-myeon, Boryeong-si. It was an open place for poets and calligraphers to freely visit during 400 years. Until today, it is widely said that Yeongbojeong was newly built by LeeRyang in 1504, who was Sugunjeoldosa(naval forces officer). The researcher investigated Gyujanggak to search Lee Maenghyu's "Asulrok-Book", and it was determined that Yeongbojeong was created by Gang Soon, 36 years earlier than LeeRyang. Accordingly, this research aimed at determining the appropriateness of the creation of Yeongbojeong. "Asulrok-Book", which said, "Yeongbojeong was Wonjeong(園亭) of Gang Soon during Yejong's reign", however this research could settle imperfection of Geungeo Gimun which was not clearly explained. Yeongbojeong was created due to Gang Soon's Wonjeong in 1468, however he was also a traitor and was executed, so that nobody wanted to mention about it. Therefore, it was determined that no phrase related to the record of creation of Yeongbojeong by Gang Soon out of lots of Yongbojeong Jeyoungsi and Gimun. Lee Maenghyu was a brave scholar who recorded 'Yeongbojeong was Gang Soon's Wonjeong' confidently, breaking such taboo. This research intended to clearly investigate the year of foundation of Yeongbojeong and establish the history of Chungcheong-Suyeong by thoroughly analyzing newly discovered "Asulrok-Book", existing "Ocheong GoonJi", and "Chungcheongsaryejib" and considering the fact relevance. As the result of this research, it was determined that Yeongbojeong was Gang Soon's Wonjeong through "Asulrok-Book". The point that Yeongbojeong was forfeited reverted to neighboring Chungcheong-Suyeong after Gang Soon was executed due to his participation in a conspiracy also was a newly discovered fact. LeeRyang, Sugunjeoldosa, can be said a brave commander, since he put up the original Yeongbojeong instead of abandoning the name Yeongbojeong of Gang soon. So far, Yeongbojeong is widely accepted as 'new construction of Yeongbojeong by LeeRyang in 1504'. However, since the record of Gang Soon's Wonjeong was discovered, and as the result of diversified analysis and examination, it is proper to correct the foundation year of Yeongbojeong as 1468.

A Study on Optimization of Picking Facilities for e-Commerce Order Fulfillment (온라인 주문 풀필먼트를 위한 물류센터 피킹 설비 최적화에 대한 연구)

  • Kim, TaeHyun;Song, SangHwa
    • The Journal of Society for e-Business Studies
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    • 제26권1호
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    • pp.67-78
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    • 2021
  • The number of domestic e-commerce transactions has been breaking its own record by an annual average growth rate of over 20% based on volume for the past 5 years. Due to the rapid increase in e-commerce market, retail companies that have difficulty meeting consumers in person are in fierce competition to take the lead in the last mile service, which is the only point of contact with customers. Especially in the delivery area, where competition is most intense, the role of the fulfillment center is very important for service differentiation. It must be capable of fast product preparation ordered by consumers in accordance with the delivery service level. This study focuses on the order picking system for rapid order processing in the fulfillment center as an alternative for companies to gain competitive advantage in the e-commerce market. A mixed integer programming model was developed and implemented to optimize the stock replenishment in order picking facilities. The effectiveness was scientifically and objectively verified by simulation using the actual operation process and data.

A study on the reform of the liberal arts curriculum based on key competencies for the innovation of liberal arts education in Universities (대학 교양교육 혁신을 위한 핵심역량 기반 교양 교육과정 개편에 대한 연구 -C 대학 사례를 중심으로)

  • Park, Jongjin
    • The Journal of the Convergence on Culture Technology
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    • 제8권1호
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    • pp.285-290
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    • 2022
  • The 21st century of the 4th industrial revolution demands 'competency' as a new educational concept that is different from that required in the industrialization era. In accordance with these changes and demands of society, universities are being called for key competency-based education and innovation in education through this by breaking away from the existing methods in liberal arts and major education. At this point, universities are presenting a comprehensive reform of liberal arts education for various financial support projects. This study presents the case of University C regarding the reform of the liberal arts curriculum for the innovation of liberal arts education in universities. According to the research results, each university is reorganizing the liberal arts curriculum in a way that can suggest various key competencies according to the university's founding philosophy and induce key competencies in the aspect of liberal arts education. For the key competency-based liberal arts curriculum of University C, we proposed various subjects for insufficient key competency subjects, various micro-degrees were proposed to specialize liberal arts education, and meta-learning-related liberal arts subjects were presented to improve basic learning ability of the students.

Breaking the Silence: Revealing the limits of Preschool Teachers' Cultural and Linguistic Competence (CLC) in Saudi Arabia

  • Allehyani, Sabha Hakim
    • International Journal of Computer Science & Network Security
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    • 제22권8호
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    • pp.222-234
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    • 2022
  • Background: Within the framework of the new Saudi Vision 2030, the education system is keen on developing Early Childhood (EC) curricula to meet the needs of children from diverse cultural and linguistic backgrounds, in addition to preparing teachers to be the main driving forces in this field. To achieve these strategic goals, the professional development of teachers has taken the lead in terms of their continuous professional achievements. Purpose: The recent study tended to explore the promotion of Cultural and Linguistic Competence (CLC) of teachers in preschool institutions in different sectors in the Kingdom of Saudi Arabia (KSA) include public, private and international. Method: In the current study, (n=300) of preschool female teachers, who had experience teaching children from diverse language and cultural backgrounds, participated voluntarily by filling out the exploratory questionnaire. It was designed on a five-point Likert scale. The credibility of the scale and the validity of the questionnaire were ascertained, and the content for which it was designed verified in terms of the purposes of the current investigation. Results: The results revealed that preschool female teachers in the private preschool settings have a higher level of CLC compared to those who were teaching in public and international preschools in KSA. In the private sector, preschool female teachers showed create abilities to provide culturally responsive environments for diverse students, applying various communication styles, and showing proper attitudes and values toward diversity. Implication: The current study provided key implications for policy makers regarding the promotion of CLC for all teachers, particularly preschool in government settings in KSA. It contributed to revealing the cultural awareness of preschool teachers' values and attitudes toward diversity.

Effect of the Slope Gradient of a Permeable Submerged Breakwater on Wave Field around It (투과성잠제의 비탈면경사가 주변 파동장에 미치는 영향)

  • Hur, Dong Soo;Choi, Dong Seok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • 제28권2B호
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    • pp.249-259
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    • 2008
  • The present paper studies the effect of the slope gradient of a fully permeable submerged breakwater using a newly developed numerical model that is able to consider the flow through a porous midium with inertial, laminar and turbulent resistance terms, i.e. simulate directly WAve-Structure (submerged breakwater)-Sand seabed interaction and can determine the eddy viscosity with LES turbulence model in 2-Dimensional wave field (LES-WASS-2D). The developed model was validated through the comparison with an existing experimental data, and further used for various numerical experiments in oder to investigate the complicated hydrodynamics on the varying slope gradient of permeable submerged breakwater. We found an acceptable phenomenon, as we expect intuitively, that reflection and transmission coefficients decrease simultaneously as slope gradient decrease. In addition, the breaking point, the circulation flow and mean vorticity around a submerged breakwater are throughly discussed.