• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.3
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• pp.163-172
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• 2014

The purpose of earthquake resistant design for typical bridges is the No Collapse Design and the Earthquake Resistant Design Part of Roadway Bridge Design Code provides a design process to construct the Ductile Failure Mechanism for the bridge structure. However, if it is not practical to provide the Ductile Failure Mechanism due to structure types or site conditions, the Brittle Failure Mechanism is an alternative way to get the No Collapse Design. As well as the existing design process constructing the Ductile Failure Mechanism, the Earthquake Resistant Design Part provides a ductility-based design process as an appendix, which is prepared for bridges with reinforced concrete piers. According to the new design process, designer determines a required response modification factor for substructure and transverse reinforcement for confinement therefrom. In this study, a typical bridge with steel bearing connections and reinforced concrete piers is selected for which the existing as well as the ductility-based design processes are applied and different results from the two design processes are identified. Based on the results, an earthquake resistant design procedure is proposed in which designers should consider the two design processes.

• Journal of Nutrition and Health
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• v.23 no.4
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• pp.229-236
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• 1990

We made S.D male rats eat 3.6% tryptophan(trp) or tyrosine(thr)-enriched diet for 4 days and measured the trp or tyr use in serum of stressed rats as well as cortisol, glucose and free fatty acid(ffa) changes in serum. When control group had received stress treatment, their tyr level has dropped significantly but no changes in trp level and their cortisol, glucose, ffa levels in serum were increased significantly all together. Trp-enrichment alone can't change serum cortisol and ffa levels but trp pools in serum and brain enlarged by dietary enrichment. Trp-enriched group's serum glucose concentration was significantly lower than control-dieted group. When trp-enriched group received stress treatment, their responses to stress were different from control-dieted group. Serum trp concentration of trp-enriched-with-stress group has dropped significantly and cortisol level was increased significantly but not as much as control-dieted-with-stress group. Glucose and ffa levels of trp-enriched-with-stress group did not increase at all. Tyr-enriched group has also larger serum pool of tyr and lowest basal cortisol level in all three diet group. tyr-enriched group's and ffa levels were in normal range and those responses to stress were same pattern with control diet group. Most importantly in tyr-enriched-with-stress group, only slight but not significant increase of cortisol level was shown.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.35-43
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• 2017

The minimum reinforcement ratio is an important design factor to prevent a brittle failure in RC flexural members. A minimum reinforcement ratio is presented by assuming an effective depth of cross-section and moment arm lever in CDC and KHBDC. In this study, it suggests that a rational method for minimum reinforcement ratio is calculated by material model and force equilibrium. As results, a minimum reinforcement ratio using a p-r curve in KHBDC is evaluated about 52~80% of recent design code's value and it induces an economical design. And also, a ductility capacity in case of placing this minimum reinforcement amount is evaluated about 89% of recent design code's value, but ductility in a member is 7 or more, so it has a sufficient ductility capacity. Therefore, it is judged that a minimum reinforcement ratio using p-r curve has a theoretical rationality, safety and economy in a flexural member design.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.64-64
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• 2023

황강댐은 임진강 상류 군사분계선으로부터 약 42km떨어진 위치에 존재하며 약 3~4억톤의 규모로 추정된다. 이에 우리나라는 약 7천만톤 규모의 군남홍수조절지를 건설하여 임진강 상류로부터 기인하는 홍수를 방어하고 황강댐의 무단방류에 대비하고 있다. 과거 2009년 9월 6일 임진강 상류 황강댐에서의 대규모 방류로 인해 경기도 연천군 일대에 홍수가 발생하여 이로 인한 인명 및 재산피해가 발생한 바 있으며, 2020년 8월 5일에는 장마전선으로 인한 폭우와 더불어 임진강 필승교 수위관측소의 수위가 급상승하면서 관측 이래 역대 최고수위가 발생하여 홍수경보가 발령되고 인근 주민이 대피하는 사례가 발생하였다. 또한, 2022년 6월 27일부터 발생한 장마전선 및 집중호우로 인해 임진강 필승교 수위관측소의 수위가 급상승하면서 홍수주의보가 발령되고 인근 주민이 대피하는 사례가 발생하였으며, 7월에는 비가 내리지 않는 상황에서 황강댐의 방류로 추정되는 유입량이 필승교 수위관측소와 군남홍수조절지에서 관측되었다. 이에 본 연구에서는 인공위성 영상에서 추출한 황강댐의 수위를 이용하여 수문모형과 저수지 운영 알고리즘을 구축하고 당시 발생한 홍수사례를 분석하여 황강댐의 운영방식을 추정하였다. 분석결과, 2020년 8월 5~7일 사이에 발생한 유입량의 경우 자체 유역 유입량은 전체 유입량대비 약 33%이나 북한 황강댐으로부터 추가로 방류된 양은 약 67%로 군남홍수조절지 유입량의 3/2 가량이 북한 황강댐의 방류량으로부터 발생된 것으로 보이며 2021년 6월에도 유사한 양상을 보였다. 하지만, 북한 황강댐의 운영방식이 용수공급을 위한 고수위 유지 운영방식에서 홍수기에 댐 월류 및 파괴를 방지하기 위한 사전방류를 수행하는 것으로 추정되었다.

• Journal of The Korean Association of Information Education
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• v.6 no.1
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• pp.1-12
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• 2002

The purpose of this paper is to design and implement a LED (LEarner Diagnosis system). Mathematics which has learning hierarchies is difficult to learn, if learners don't understand previous learning contents. Before a learner starts learning, the LED offers diagnostic problems to diagnose the learner's understanding ability of the previous learning contents. If the learner don't understand it, then the LED present supplementary contents. After finishing the study, the learner has to pass the test to diagnose whether the learner do mastery learning. The LED makes learners do supplement previous contents, if learners don't understand it, and master all of the contents, learners can achieve learning object.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.591-598
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• 2019

The statistics of committing suicide in S. Korea is ranked in top with serious attempts of falling among OECD countries since 2003. The rates is slightly dropped by 5 percent point, nevertheless the falling is still high for the age of over 10 years old and this matter must be solved. Most of the case of suicides are the falling based on a trend view of falling which is serious matter and cannot be solved easily for both domestic and foreign countries. For example, the steel net of falling prevent was installed in the Golden Gate Bridge costed by 200 million-dollar. In New Zealand, the steel net of falling prevention had been removed and re-installed beccause of the high suicide rates. Canada and Australia also surrounded the bridge with steel fences to prevent suicide without consideration of the beauty of bridge. Therefore, this paper suggested a comparison study on both falling prevention systems in all countries and patent technologies. Also, it covers the blocking skills of approach in both security and limited area. This paper suggested the technical Rollinder system equipped with the mechanical apprentice to prevent effectively the falling sucides and wall passing. Before the installation of Rollinder System by 2016, there were 33 person who tried to fall in the river in Machang Bridge. However, the number of the committing suicides were dramatically reduced to zero after the installation of the system.

• Korean Journal of Plant Taxonomy
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• v.50 no.2
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• pp.199-226
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• 2020

Hwangmaesan Mt. (1,108 m) is rich in forest biodiversity and is a part of the Sobaek mountain range located in Hapcheon-gun, Gyeongsang-do in Korea. Unfortunately, the biodiversity and ecosystem integrity of Hwangmaesan Mt. have recently been threatened by heavy human disturbances. We conducted thirteen field surveys between March and October of 2019 to investigate the vascular flora in Hwangmaesan Mt. Through this extensive survey, we found 628 taxa consisting of 106 families, 349 genera, 554 species, 16 subspecies, 48 varieties, and 10 forma. Based on a comparative analysis between the present findings and former flora reports, our results showed an increase by 28 percent in the number of taxa observed. Of the 628 taxa, dicotyledons made up the largest group (477 taxa, 76.0%) followed by monocotyledons (120 taxa, 19.1%). Endemic plants consisted of 16 taxa, with rare plants designated by the Korea Forest Service numbering 14 taxa. Ten taxa were listed on the Red list by the Ministry of the Environment. The floristic target species designated by the Ministry of the Environment numbered 75 taxa, whereas there were 42 taxa of invasive plants.

• Journal of the Korea Concrete Institute
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• v.23 no.3
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• pp.303-310
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• 2011

To replace a steel box bridge for constructions of medium span bridges in Korea, the Hybrid Truss Bridge (HTB) is being considered as an alternative bridge type. The core technology of HTB is the connection joint that links the concrete slabs and steel truss pipes. Various construction companies in Japan have developed unique connection systems and applied to the real bridge constructions after verifying their performances through the experimental evaluation. In this study, the fatigue test of a hybrid truss girder has been performed in order to verify the newly proposed hinge type connection joint`s static and fatigue capacities. Through this fatigue test results, it is founded that the structural detail to improve the fatigue capacity should be developed. The hinge connection system with circular ribs has been proposed by means of structural finite element analyses. And then the fatigue test for this connection joint has been performed and it is proved that this connection joint has enough fatigue capacity. Finally, it is expected that the hinge connection system with circular ribs developed by in this study can be easily applied to the real bridge.

• Ecology and Resilient Infrastructure
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• v.2 no.3
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• pp.191-197
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• 2015

Invasive alien species are considered to be one of the main factors that cause biodiversity loss. Establishment of management strategies through continuous monitoring and risk assessment is a key element for invasive alien species management policy. In the present study, we introduce examples of ecological risk assessment tools developed in Japan, Germany-Austria and Belgium. Invasive alien species have been designated in Japan based on the assessment of risks to ecosystems, human health and primary industry. German-Austrian Black List Information System categorized alien species into Black List, White List and Grey List according to their risks to biodiversity. In the Harmonia Information System developed in Belgium, invasiveness, adverse impacts on native species and ecosystem functions and invasion stages were assessed and alien species were categorized into Black List, Watch List and Alert List. These international risk assessment tools may be helpful to improve our national risk assessment protocol for the prioritization of invasive alien species management.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.249-250
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• 2016

본 논문에서는 3병렬 풍력발전 시스템의 직류단 전류 리플을 저감하기 위한 인터리빙 기법을 제안한다. 병렬 구조의 풍력발전 시스템은 각 발전기 측 컨버터의 전류 고조파로 인해 직류단에 전류 리플이 발생한다. 이러한 전류 고조파들의 합과 관련된 전류 리플은 직류단 커패시터의 수명 단축 및 전체 시스템의 손실을 유발한다. 이를 방지하기 위해 3병렬 풍력발전 시스템에서의 전류 고조파를 분석하고, 전류 리플을 최소화하기 위한 최적의 인터리빙 각을 구하여 전류 리플을 저감하는 기법을 제안한다. 제안하는 기법의 타당성을 PSIM 시뮬레이션을 통해 확인한다.