• 한국경영과학회지
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• 제6권1호
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• pp.15-23
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• 1981

This paper deals with cross impact analysis for technology assessment. The focus of the paper is to develop new technique of cross impact matrix using goal programming method. In this study, the idea of cross impact analysis based on scenario generation method especially SMIC-74 (2) is expanded. Critical literature review on SMIC-74 is presented to discuss the mathematical rationale of consistent probability in cross impact analysis. A new model of cross impact analysis using goal programming to overcome the shortcomings of the scenario generation technique especially SMIC-74 is developed. This new technique is also applied to the assessment of the air pollution problems in Seoul Metropolitan area in Korea. The results of analysis give us following findings 1) Cross impact analysis using goal programming produce more meaningful solutions comparing to those of SMIC-74 2) Theoretical rationale of the objective function in the newly developed technique is more appropriate than that of SMIC-74.

• Fibers and Polymers
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• 제1권1호
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• pp.45-54
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• 2000

Impact behaviors of the large deformable composites of Kevlar fiber reinforced composites of different preform structures have been investigated. An analytic tool was developed to characterize the impact behavior of the Kevlar composites. The image analysis technique, and deply technique were employed to develop energy balance equation under impact loading. An energy method was employed to establish the impact energy absorption mechanism of Kevlar multiaxial warp knitted composites. The total impact energy was classified into four categories including delamination energy, membrane energy, bending energy and rebounding energy under low velocity impact. Membrane and bending energy were calculated from the image analysis of the deformed shape of impacted specimen and delamination energy was calculated using the deplying technique. Also, the impact behavior of Kevlar composites under high velocity impact of full penetration of the composite specimen was studied. The energy absorption mechanisms under high velocity impact were modelled and the absorbed energy was classified into global deformation energy, shear-out energy, deformation energy and fiber breakage energy. The total energy obtained from the model corresponded reasonably well with the experimental results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.911-916
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• 2008

Impact noise caused by the collision of bodies is difficult to estimate because of the complexity of impact phenomenon. In this study, impact noise is estimated using two different methods when the noise is caused by the vibration due to impact. First, impact noise is analyzed using impact analysis and boundary element analysis. Second, modal expansion technique is applied to the estimation of impact noise. Experiment is carried out to validate the analysis results.

• 콘크리트학회논문집
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• 제15권6호
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• pp.924-929
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• 2003

A majority of infrastructures has been deteriorated over time. Therefore, it is very important to verify the quality of construction, and the level of structural deterioration in existing structures, to ensure their safety and functionality. Many researchers have studied non-destructive testing (NDT) methods to identify structural problems in existing structures. The impact echo technique is one of the widely used NDT techniques. The impact echo technique has several inherent problems, including the difficulties in P-wave velocity evaluation due to inhomogeneous concrete properties, deterioration of evaluation accuracy where multiple reflection boundaries exist, and the influence of the receiver location in evaluating the thickness of the tested structures. Therefore, the objective of this paper is to propose an enhanced impact echo technique that can reduce the aforementioned problems and develop a Virtual Instrument for the application via a thickness evaluation technique which has same technical background to find deterioration in concrete structures. In the proposed impact echo technique, transfer function from dual channel system analysis is used, and coherence is improved to achieve reliable data. Also an averaged signal -ensemble- is used to achieve more reliable results. From the analysis of transfer function, the thickness is effectively identified.

• 대한조선학회논문집
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• 제45권6호
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• pp.726-734
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• 2008

While the structural safety assessment of Cargo Containment System(CCS) in membrane type LNG carriers has to be carried out in consideration of sloshing impact pressure, it is very difficult to figure out its dynamic response behaviors due to its very complex structural arrangements/materials and complicated phenomena of sloshing impact loading. For the development of its original technique, it is necessary to understand the characteristics of dynamic response behavior of CCS structure under sloshing impact pressure. In this study, for the exact understanding of dynamic response behavior of CCS structure in membrane Mark III type LNG carriers under sloshing impact pressure, its wet drop impact response analyses were carried out by using Fluid-Structure Interaction(FSI) analysis technique of LS-DYNA code, and were also validated through a series of wet drop experiments for the enhancement of more accurate shock response analysis technique. It might be thought that the structural response behaviors of impact response analysis, such as impact pressure impulses and resulted strain time histories, generally showed very good agreement with experimental ones with very appropriate use of FSI analysis technique of LS-DYNA code, finite element modeling and material properties of CCS structure, finite element modeling and equation of state(EOS) of fluid domain.

• 환경영향평가
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• 제21권1호
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• pp.119-132
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• 2012

Biodiversity is a key element of ecosystem of which function provides essential product and service in human life. In the course since development projects often causes damages to biodiversity, environmental impact assessment technique must be capable of accurately assessing potential impact from flora and fauna and to entire ecosystem. Korea needs improvement of its assessment technique that is compatible with Korean environmental regulatory standard that is generally stricter than that of most countries. This study attempts to explore both domestic and overseas biodiversity assessment techniques and analyze each stage of environmental impact assessment. The data is collected from numbers of literatures selected by navigating both domestic and overseas literature database with certain keywords. Among the 44 selected papers, overseas publications outnumber those of domestics, and there are more researches on assessment methodology of biodiversity than assessment tool and model. In terms of environmental impact assessment, the number of papers on environmental impact forecast exceeds the numbers of papers on current state of environment and the impact minimizing solution. Therefore, contents and trends of those researches in the different stages of environmental impact assessment discussed in this paper not only suggest potential impact on biodiversity and minimization solutions in detail, but is also a valuable resource particularly for biodiversity relevant environmental assessment technique improvement in Korea. Proposing of a new direction of improvement in biodiversity assessment techniques makes this study significant, and further research for preservation of biodiversity should follow up to provide an improvement scheme for biodiversity assessment techniques in the future.

• 환경영향평가
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• 제11권2호
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• pp.109-116
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• 2002

The diagnostic and prognostic methods for generating 3 dimensional wind field were comparatively analyzed and 4 dimensional data assimilation (FDDA) technique by incorporating Automatic Weather System (AWS) into the prognostic methods was discussed for the urban scale air quality model. The A WS covered the urban scale grid distance of 10.6 km and 4.3 km in South Korea and Kyong-in region, respectively. This is representing that AWS for FDDA could be fairly well accommodated in prognostic model with the meso${\gamma}$~ microa scale (~5 km), indicating that the 3 dimensional wind field by FDDA technique could be a useful interpretative tool in urban area for the atmospheric environmental impact assessment.

• 한국표면공학회지
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• 제35권6호
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• pp.408-414
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• 2002

TiN and TiAlN coating layer were deposited on WC-Co steel substrates by an arc ion plating(AIP) technique. The crystallinity and morphology for the deposited coating layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impact behaviors of the deposited TiN and TiAlN coating layer were investigated with a ball-on-plate impact tester. Beyond $10^2$ impact cycle, TiAlN coating layer showed superior impact wear resistance compared to TiN coating layer. On the other hand, both TiN and TiAlN coating layers started to be partially failed between $10^2$ and $10^3$ impact cycle. Above $10^3$ impact cycle, TiN and TiAlN coating layers showed similar impact behavior because of the substrate effect.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.715-722
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• 2012

A structural health monitoring (SHM) technique for locating impact position in a composite plate is presented in this paper. The technique employs a single sensor and spatial focusing properties of time reversal (TR) and inverse filtering (IF). We first examine the focusing effect of back-propagated signal at the impact position and its surroundings through simulation. Impact experiments are then carried out and the localization images are found using the TR and IF signal processing, respectively. Both techniques provide accurate impact location results. Compared to existing techniques for locating impact or acoustic emission source, the proposed methods have the benefits of using a single sensor and not requiring knowledge of material properties and geometry of structures. Furthermore, it does not depend on a particular mode of dispersive Lamb waves that is frequently used in the SHM of plate-like structures.

• 한국항공우주학회지
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• 제37권7호
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• pp.693-700
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• 2009

본 논문에서는 복합적층판의 취약한 층간 특성을 보강할 수 있는 z-피닝 기술에 대하여 기존에 알려진 방법들을 소개하고, 최근 저자에 의하여 제안된 새로운 방법을 소개하였다. 새로운 방법을 적용하여 시제작된 z-피닝 시편들에 대하여 충격시험을 수행하고, 충격손상 영역을 측정하였다. z-피닝 기술이 적용되지 않은 일반 복합재 시편에 대해서도 동일한 시험을 수행하고, 두 결과를 서로 비교하였다. 결과적으로 새로운 z-피닝 기술은 기존의 기술에 비하여 양산에 적용하기가 매우 유리한 장점이 있으며, 새로운 z-피닝 기술이 적용된 복합적층판 시편들의 내충격 특성이 확실히 향상되고 있음을 알 수 있었다.