• Magazine of the Korea Concrete Institute
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• v.5 no.4
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• pp.135-144
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• 1993

A fatigue analysis procedure for prestressed concrete composite girder bridges is established, which includes the time-dependent effects of component materials. The procedure can take into account the movement of neutral axis depth as crack develops and give quite good agreement with experimental results available. It is also assured that Korean Standard prestressed concrete composite girder has enough fatigue resistance. The procedure in this paper gives a way to express the fatigue capacity of prestressed concrete beams in the form of S-N curve, which can be utilized under variable amplitude fatigue load.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.191-191
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• 2023

기후변화 대응을 위한 탄소 중립의 중요성이 대두되는 요즘, 생태계의 가장 큰 메탄 저장소로서 지구의 탄소 순환에 주요한 영향을 미치는 습지에 대한 이해는 필수적이다. 전지구 지면 모델인 Community Land Model(CLM)에 Functionally Assembled Terrestial Ecosystem Simulator(FATES) 외부 모듈을 함께 구동한 지면 생태계 모델 CLM-FATES는 지면 heterogeneity와 다양한 식생 종류를 고려하여 에너지 플럭스, 토양 수문, 생화학적 과정 등을 모의함으로써 탄소 동태 변화를 포함한 장기적 생태계 동태 변화 모의를 가능하게 한다. 본 연구는 CLM-FATES 모델을 미국 캘리포니아주 Mayberry Wetland (US-Myb)와 Twitchell East End Wetland (US-Tw4)에 적용하였다. 모델의 대기 입력 자료로는 FLUXNET-CH4에서 제공하는 에디 공분산 기반 플럭스 관측 자료를 사용하였다. 기존 CLM-FATES 모델은 토양이 장기간 포화 혹은 침수되어 지표 위 혹은 지표면 가까이 발달한 지하수면을 가지고 있는 습지의 수문학적 특성을 잘 반영하지 못해 정밀한 습지 생태계 동태 변화 모의에 한계를 가지고 있다. 본 연구에서는 CLM-FATES를 통한 보다 정확한 습지 생태계 모의를 위해 모델 내 토양 수문 관련 모듈을 수정하여 모델이 습지의 수문학적 특성을 반영할 수 있도록 하였다. 모델 구동 결과 도출한 잠열, 총일차생산량(Gross Primary Production: GPP)과 순생태계생산량(Net Ecosystem Production, NEP) 플럭스, 메탄 플럭스, 엽면적지수(Leaf Area Index; LAI)와 지표수 높이에 대해 관측값 대비 RMSE 및 R² 값을 계산하여 모의 결과의 적절성을 분석하였다. 이러한 모델 개선 경험을 바탕으로 추후 우리나라 습지 사이트에 모델을 적용하여 습지 탄소 동태 예측에 활용할 계획이다.

• Cement Symposium
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• s.49
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• pp.29-30
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• 2022

Since the climate problem getting severe, carbon neutrality is rising global issue. The limestone powder addition that can substitute clinker in cement is look forward to get positive effect as filler. This study focus on the effect of limestone powder chemical characteristic on mortar workability and compressive strength. Consequently, regardless of type of limestone and subsitution amount, the compressive strength was lower then OPC. But the workability of limestone composite cement showed higher then OPC. Considering latter strength development, using unit water decreasing effect of limestone composite cement is planned further.

• Korean Journal of Breeding Science
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• v.51 no.4
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• pp.475-481
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• 2019

The soybean cultivar 'Neulchan' was developed for production of soy-paste and tofu. SS91501-9-1-1 and SS96205 (F₂) were crossed in 1998, and F₃ to F₇ were selected by the pedigree method. A preliminary yield trial (PYT) and an advanced yield trial (AYT) were conducted from 2006 to 2008, and a regional yield trial (RYT) in nine regions was conducted from 2009 to 2011. In the RYT, 'Neulchan' was stable in variable environments and generated high yield. 'Neulchan' was determinate with white flower, light brown pod color, yellow spherical seed, and yellow hilum. Its flowering date and maturity date were Jul. 30 and Oct. 9, respectively. The plant height was shorter than that of 'Daewonkong' (a standard cultivar). 'Neulchan' had the same node number (14), higher first-pod height (12 cm), and lighter seed weight (21.7 g/100-seed weight) than those of 'Daewonkong' (14, 11, and 24.2 g/100-seed weight, respectively). 'Neulchan' had high resistance to bacterial pustule, and its resistance to soybean mosaic virus was similar to that of 'Daewonkong'. The yield and color of 'Neulchan' tofu were similar to those of 'Daewonkong' tofu, but the hardness was lower than that of 'Daewonkong' tofu. The soybean malt scent, fermented soybean yield, and γ-polyglutamic acid (γ-PGA) of 'Neulchan' were 3, 215%, and 24.6 mg/g, respectively. Its yield in adaptable regions was 307 kg/10a, higher than that of 'Daewonkong'. 'Neulchan' was expected to be cultivated and used widely for soy-paste and tofu production. (Registration No. 4904).

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.97-106
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• 2011

Construction Management is the overall management of the project as construction manager and the owner are united together. Construction manager's role is to conduct the overall or partial construction administration in the 'design, bid, build' process, in the owner's interests with maintaining technical neutrality. Construction manager is becoming one of new professionals in the building process and the contract defines their roles and the range of services, so high level of ethnics are required. This study suggests the legal status of the construction manager and the ethnic standards and the ethnic's characteristics. In conclusion, firstly, the legal characteristics of the administration of construction management are the delegations contract, the responsibility of negligence and the duty of due diligence, abided by the contract that ties between the owner and the construction manger. Secondly, the administerial characteristics of the construction management are the role of mediator, the service of professional technology, accountability to the owner and publicness. Thirdly, due to these characteristics, as a professional, the standard of ethnic assessment for the construction project manager are intention, act and result, so with the relation to that, morality, deontology and consequentialism have been suggested in this study.

• The Journal of the Korea Contents Association
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• v.10 no.1
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• pp.275-285
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• 2010

This research examines the relation of dissatisfaction about own real conditions, deviant labeling, self-esteem, abuse from parent, victimization and juvenile delinquency(smoking, drinking, run-away, assault, taking away stuffs or money, larceny). The evidence of a strong relation of these factors and girls' delinquency is well known through empirical researches by feminist criminologists. Feminist criminology had attention to the gender-specific factors that could explain girls' delinquency. Most of conventional delinquency theories, such as social bond theory, differential association theory, focused on bad boys' deviant behaviors. These theories has not been designed to apply to girls' troubles. According to the conclusion of the research, there seems to support researches of feministic perspectives.

• Journal of dental hygiene science
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• v.7 no.2
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• pp.59-64
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• 2007

As the number of elderly grows in today's modern socity, dental hygienist's role is more emphasized than ever before for hygiene management of the aged. It is also find out college students knowledge, attitude and behavior towards the elderly Form March and May 2007 three monthly during collected. This is study conducted through interview with college students who are majoring in dental hygiene of health care in Gyeong-Ju and will be in charge of oral hygiene According to the interview, this study obtains the following results: 1. The level of undergraduate students knowledge of elderly shows a total score of $8.39{\pm}2.80$. 2. The average score of undergraduate students attitude toward elderly is in a neutral range(50~70), recording $55.1{\pm}8.66$ on a scale of 100. 3. The average score of undergraduate students behavior toward elderly is in a neutral range(43~60), recording $28.7{\pm}6.17$on a scale of 85 and showing negative behavior. 4. Participating in volunteer job lead the significant differences in undergraduate students attitude toward elderly. 5. Participating in volunteer job lead the significant differences in undergraduate students behavior toward elderly, That is undergraduate students volunteer job with the show a positive behavior towards elderly.

• Journal of Conservation Science
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• v.34 no.6
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• pp.557-568
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• 2018

The manufacturing techniques were studied by investigating a precise analysis on wall structure, features of materials and the painting layer of the bracket mural paintings at Daeungbojeon Hall in Naesosa temple. The wall frame is a single-branch structure, and The mural paintings are composed of 3 layers which are a support layer, a finishing layer and a painting layer. The support layer and the finishing layer are an earth wall that sand and clay such as Quartz, Feldspar, and etc. are mixed. The support and the finishing layers have a combination of medium particle sand and smaller than fine particle sand in the approximate ratios of 0.8:9.2 and 6:4, respectively. Therefore, the aforementioned ratio of sand with medium or large particles is relatively higher in the finishing layer than the support layer. As a result of a precise analysis on the painting layer, it has a relatively thick ground layer for painting which is maximum $456.15{\mu}m$ by using Celadonite or Glauconite and the paintings were colored by using pigments such as Atacamite, Kaolinite or Halloysite, Oxidized steel, and etc. on it. The manufacturing style and the painting techniques of an earth wall are included in the category of the Joseon Dynasty style that have been studied up to now, but the facts that the finishing layer has a high content of sand and a middle layer and chopped straw have not been identified. These are remarkable points in terms of structure and materials, and can be crucial in the evaluation of the state of conservation of mural paintings or preparation of a conservation plan.

• Journal of Internet Computing and Services
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• v.22 no.4
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• pp.123-134
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• 2021

This paper suggests that the Internet is not free through analysis of U.S. Internet history and lawsuits related to the Charter merger in 2016. Generally speaking, the players in internet connectivity market agree to Non-Disclosure Agreement, when connecting their facilities and networks each other. So, I adopted the case study & analysis as research methodologies due to limitation of collecting the transaction data between them. The former finds that Internet access has never been free in U.S Internet history. As we know, some including Content Providers(CPs) argue that the Internet is a free network and there are many cases to use the internet for free, so they came to conclusion that ISPs have no right to charge the users like CPs. This study refutes these arguments in two ways. One is that using the internet has never been free. From ARPANET, known as the beginning of the U.S. Internet, to the commercialization of backbone, no Internet has been considered or implemented for free since the early Internet network was devised. Also, the U.S government was paying subsidies or institutions were paying fees to secure network operations for the NSFNET backbone. the other is that "free peering" refers to barter transactions between ISPs, not to free access to counterpart internet networks. Second, this study analyze the FCC' executive order of conditioned merger approval and the court's related ruling and verify that using the internet is not free. According to the analysis, this study finds that it's real situation to make paid settlements between ISP-CPs (including OTTs) in the US Internet market at the moment. This study concludes that the Internet has never been free in terms of its technical characteristics, network structure, network operation, and system. Also it proposes how to improve the domestic settlement system between ISPs-CPs in terms of policy and regulation.

• Clean Technology
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• v.28 no.3
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• pp.238-248
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• 2022

The world is striving to transition to a carbon-neutral society. It is expected that using hydrogen instead of hydrocarbon fuel will contribute to this carbon neutrality. However, there is a need for combustion technology that controls the increased NOx emissions caused by hydrogen co-firing. Flameless combustion is one of the alternative technologies that resolves this problem. In this study, a numerical analysis was performed using the 1D opposed-flow diffusion flame model of Chemkin to analyze the characteristics of flameless combustion and the chemical reaction of methane-hydrogen fuel according to its hydrogen content and flue gas recirculation rate. In methane combustion, as the recirculation rate (K_v) increased, the temperature and heat release rate decreased due to an increase in inert gases. Also, increasing K_v from 2 to 3 achieved flameless combustion in which there was no endothermic region of heat release and the region of maximum heat release rate merged into one. In H₂ 100% at K_v 3, flameless combustion was achieved in terms of heat release, but it was difficult to determine whether flameless combustion was achieved in terms of flame structure. However, since the NOx formation of hydrogen flameless combustion was predicted to be similar to that of methane flameless combustion, complex considerations of flame structure, heat release, and NOx formation are needed to define hydrogen flameless combustion.