• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.177-180
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• 2007

Numerical simulations on the suspended load in the Do jang fish port are carried out. Suspended load is analysed by using the two-dimensional advection-diffusion equation. To describe behaviors of a pollutant in costal zone, a split-operator method is applied to the numerical model. The advection part is first solved by SOWMAC and then the diffusion part is solved by a three-level locally implicit scheme.

• 항공우주시스템공학회지
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• 제9권2호
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• pp.41-46
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• 2015

The various risk factors that affected schedule, costs and mission success, etc. in development of the satellite. This paper derives the considerable "Cost of Quality" factors in the satellite development phase through the survey of practical techniques in respect of measurement of quality cost in the commercial products manufacturing, and proposes mitigation strategy of quality cost using the approach that can be minimized it.

• 한국방재학회 논문집
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• 제4권3호
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• pp.73-81
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• 2004

본 연구에서는 염해에 대한 내구성 저하 요인을 국내외 자료에 의해 요인별 분석, 고찰하고 Fick의 확산 방정식을 적용하여 설계기준강도와 물-시멘트비에 따른 염화물의 확산계수와 내구년한에 의한 환경조건별 소요피복두께를 산출하여 각 변수들의 변화에 따른 영향을 고찰하였다. 물-시멘트비가 감소하고 설계강도가 증가되면 염화이온의 침투속도가 낮아져 소요피복두께를 줄이는 것으로 나타났다. 특히 비말대 환경조건에서 고강도 콘크리트에 고로슬래그 시멘트를 사용할 경우 염화이온의 확산을 막는데 더욱 효과적이였다. 결과적으로 고내구성을 필요로 하는 해양콘크리트 구조물의 경우 최소피복두께 기준인 8cm보다 환경조건에 따라 $3{\sim}8cm$의 피복두께가 증가되어야 1등급 내구년한을 만족시키는 것으로 나타났다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.203-204
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• 2023

Recycled aggregate is an aggregate that satisfies the quality as an aggregate by crushing waste concrete and passing it through a separator. The government grants a floor area ratio of up to 15% and building height mitigation when more than 25% of the recycled building materials are used. In addition to environmental protection issues, it is necessary to actively utilize recycled aggregates that meet the standards to secure the business feasibility of buildings. This study attempted to derive the results according to the substitution rate by measuring the chloride ion diffusion characteristics based on the electrophoresis method.

• 한국방재학회 논문집
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• 제9권1호
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• pp.15-20
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• 2009

해양환경 하에 건설되는 콘크리트구조물은 다양한 염해 환경에 노출되어 있으며, 이중 염소이온의 침투 및 확산으로 인한 콘크리트 중의 철근부식과 화학적 침식 등은 콘크리트구조물의 주요 성능저하 요인으로 지적되고 있다. 따라서 해수 중의 염소이온의 침투 및 확산 메커니즘을 효율적으로 평가하기 위하여 전기화학적 촉진시험으로부터 염소이온의 확산계수를 추정하였다. 또한 콘크리트의 압축강도, 투수공극량 및 염소이온의 침투깊이 등과 염소이온의 확산계수와의 상관관계를 분석하기 위하여 회귀분석을 실시하였다. 본 연구의 시험결과에 의하면, 물-시멘트비 40~60%의 범위에서 보통콘크리트의 염소이온 확산계수는 $2.5{\sim}6.6{\times}10^{-12}m^2/s$ 정도였으며, 염소이온의 확산계수와 콘크리트의 물성과의 상관관계는 선형의 상관관계가 있었다.

• Journal of Welding and Joining
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• 제31권3호
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• pp.17-21
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• 2013

Sn whiskers are one of the serious causes of the failure of electronics. Sn whiskers grow spontaneously from Sn-based, lead-free finished surfaces, even at room temperature. A primary factor of these Sn whiskers growth is compressive stress, which enhances the diffusion of Sn or other elements. The sources of compressive stress are the growth of non-uniform large intermetallic compounds along the interface between the Sn grain boundary and Cu substrate. Recent studies revealed the methods for reducing Sn whisker growth. This paper gives an overview about recent researches for mitigation methods of Sn whisker growth during nearly room temperature storage.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권10호
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• pp.5035-5048
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• 2016

Nano scale networks are futuristic networks deemed as enablers for the Internet of Nano Things, Body area nano networks, target tracking, anomaly/ abnormality detection at molecular level and neuronal therapy / drug delivery applications. Molecular communication is considered the most compatible communication technology for nano devices. However, connectivity in such networks is very low due to inter-symbol interference (ISI). Few research papers have addressed the issue of ISI mitigation in molecular communication. However, many of these methods are not adaptive to dynamic environmental conditions. This paper presents an enhancement over original Memory-1 ISI cancellation scheme using maximum likelihood estimation of a channel parameter (λ) to make it adaptable to variable channel conditions. Results of the Monte Carlo simulation show that, the connectivity (P_conn) improves by 28% for given simulation parameters and environmental conditions by using enhanced Memory-1 cancellation method. Moreover, this ISI mitigation method allows reduction in symbol time (Ts) up to 50 seconds i.e. an improvement of 75% is achieved.

• 한국전기전자재료학회논문지
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• 제37권4호
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• pp.347-357
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• 2024

Oxide semiconductor gas sensors are widely used for detecting toxic, explosive, and flammable gases due to their simple structure, cost-effectiveness, and potential integration into compact devices. However, their reliable gas detection is hindered by a longstanding issue known as humidity dependence, wherein the sensor resistance and gas response change significantly in the presence of moisture. This problem has persisted since the inception of oxide semiconductor gas sensors in the 1960s. This paper explores the root causes of humidity dependence in oxide semiconductor gas sensors and presents strategies to address this challenge. Mitigation strategies include functionalizing the gas-sensing material with noble metal/transition metal oxides and rare-earth/rare-earth oxides, as well as implementing a moisture barrier layer to prevent moisture diffusion into the gas-sensing film. Developing oxide semiconductor gas sensors immune to humidity dependence is expected to yield substantial socioeconomic benefits by enabling medical diagnosis, food quality assessment, environmental monitoring, and sensor network establishment.

• Structural Engineering and Mechanics
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• 제15권6호
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• pp.669-683
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• 2003

The stochastic optimal nonlinear control of coupled adjacent building structures is studied based on the stochastic dynamical programming principle and the stochastic averaging method. The coupled structures with control devices under random seismic excitation are first condensed to form a reduced-order structural model for the control analysis. The stochastic averaging method is applied to the reduced model to yield stochastic differential equations for structural modal energies as controlled diffusion processes. Then a dynamical programming equation for the energy processes is established based on the stochastic dynamical programming principle, and solved to determine the optimal nonlinear control law. The seismic response mitigation of the coupled structures is achieved through the structural energy control and the dimension of the optimal control problem is reduced. The seismic excitation spectrum is taken into account according to the stochastic dynamical programming principle. Finally, the nonlinear controlled structural response is predicted by using the stochastic averaging method and compared with the uncontrolled structural response to evaluate the control efficacy. Numerical results are given to demonstrate the response mitigation capabilities of the proposed stochastic optimal control method for coupled adjacent building structures.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.169-174
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• 1999

The reclamation area of Saemangeum (Kunsan) located between 126$^{\circ}$10' -126$^{\circ}$50'E and and 35$^{\circ}$35'N -36$^{\circ}$05'N at the western coast of Korea. The construction of the 33km sea dike is building in the Saemangeum area. When the construction of the sea dike in the coastal region takes plase, there exists a certain amount of soil which is diffused by the tidal current. Behavior of the soil diffusion usually depends on its intrinsic characteristics, bathymetry, construction method and used mchinery. The amount of soil at the construction acts as a pollutant which is the cause of changing the marine environment. When the soil material is diffused , it may form a layer which obstructs the light passing into the sea and causes the extinction or alteration of the living beings on the sea bottom. The settlement of soil material could change the sea bottom deposit. The purpose of MITIGATION is to harmonize the development and the conservation of environment, to restrict environmental destruction and to reproduce the enviroment damaged by the construction in the coastal region. The purpose of this study is to find the method by which we minimize the anti-function of development in the coastal region. Tide and tidal current are calculated using a two-dimensional numerical model before the construction of sea dike in Saemangeum Bay. The numerical results are compared well with field observations. On the basis of these results, we caculated the tide and tidal current after the construction of the sea dike in order to investigate the change of the tide and tidal current after the construction of the sea dike. Moreover, we calculated the tide and tidal current after the construction of submerged breakwater in order to preserve the enviornmental condition of creature habitat . We compared the tide and tidal current before and after the construction of submerbed breakwater, to investigate the possbility of MITIGATION in the fisheries.