• 환경생물
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• 제36권4호
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• pp.456-462
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• 2018

The purpose of this study was to assess cross-generational effects of bisphenol A exposure in benthic copepods, Tigriopus west. Nauplii (<24 hours old) were exposed to graded concentrations of bisphenol A, and toxicity end-points such as survival, development, sex ratio, and fecundity were measured. $F_1$ generations were grown under innoxious conditions, and similarly assessed. Significant differences were observed in development of nauplii and copepodites, between exposed and non-exposed copepods; however, there were no differences in survival of nauplii or copepodites, sex ratio, or brooding rate in parental generation. In contrast, in the $F_1$ generation, there were significant differences between the control group and exposed group in survival and development of nauplii. Length, width, and biomass of parental and $F_1$ generations were reduced in the exposed group compared to the control group. In addition, some deformities, such as swelling of the prosome, abnormally shaped egg sac, and dwarfism were observed after exposure to bisphenol A. So, our study demonstrates that a cross-generation toxicity test and monitoring of morphological deformities in harpacticoid copepods, can be useful for development of potential bioindicators for environmental monitoring, and assessment of chemical impact.

• 국제초고층학회논문집
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• 제11권2호
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• pp.75-86
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• 2022

High-rise buildings often can accommodate the population of small horizontal cities. The investment in high-rise buildings is considerable and therefore a rapid return on investment is necessary. The immediate availability of high-rise buildings can be achieved by automated prefabrication of highly finished modules and their instant on-site assembly by robotic and automated construction sites. A high-rise building as a vertical city can be considered as a sophisticated organism that can constantly change throughout its lifecycle in response to economic growth, demographic change, and environmental pressures. To date, many new urban high-rise developments claim to be "vertical cities", yet few represent this important characteristic. This article analyzed the technological readiness and innovations in the field of construction automation and robotics including single-task construction robots, automated on-site construction factories, and ambient assisted living. These technological advances enable the realization of future vertical cities that are able to continuously grow and transform in terms of form and function. Finally, the article proposes a visionary archetype of vertical city in the name of "dynamic vertical urbanism" that is easy to expand vertically and horizontally in order to achieve instant availability and full life cycle resilience thanks to advanced building technologies.

• 비파괴검사학회지
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• 제22권5호
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• pp.539-544
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• 2002

기계구조물의 피로과정에 대한 손상정도를 평가하기 위하여 X선 회절을 이용하여 반가폭 및 하중방향과 수직방향에서의 2축에 대한 잔류응력의 변화를 측정하였다. 반가폭은 피로과정의 초기에는 큰 변화를 보이지만 피로수명 비의 약 $10{\sim}20%$ 이후에는 큰 변화를 보이지 않았다. 2축 방향에 대한 잔류응력은 피로수명비의 40% 전후에서 길이방향의 경우는 감소와 증가를, 폭방향의 경우는 증가와 감소를 하였으며, 응력진폭이 클수록 잔류응력의 절대 값은 커지는 증가하는 경향을 나타내었다.

• 한국CDE학회논문집
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• 제16권4호
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• pp.268-276
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• 2011

The product-level carbon footprint (PCF) is a comprehensive and widely accepted metric for sustainable product development. However, since a full PCF study in general is time and cost intensive, it is not feasible for the product development team to synchronize the activity to the main product development process. In addition, the current dedicated life cycle assessment (LCA) tools for calculating PCF, separated from the main product data management systems, have limitations to provide timely PCF information for design decision makings and collaborations between design and environment engineers. This paper examines the possibility of the extension of the current product data model that can support the PCF calculation with PDM (Product Data Management) databases. The product data model can represent not only the content of products but also context or system information of the products. The product data model can be implemented as a PDM database that can satisfy the needs for handy and timely PCF calculations from the consistent product data for dynamic design decision makings and engineering collaborations.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.780-783
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• 2002

This paper proposes an approximate LCA methodology fur the conceptual design stage by grouping products according to their environmental characteristics and by mapping product attributes Into impact driver (ID) index. The relationship Is statistically verified by exploring the correlation between total impact indicator and energy impact category. Then an artificial neural network model is developed to predict an approximate LCA of grouping products in conceptual design stage. The training is generalized by using identified product attributes for an ID In a group as well as another product attributes for another IDs in other groups. The neural network model with back propagation algorithm is used and the results are compared with those of multiple regression analysis. The proposed approach does not replace the full LCA but it would give an approximate LCA results for design concepts.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.643-652
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• 2009

This paper presents brief history and a state-of-the-art survey of Life Cycle Cost (LCC) analysis, in particular LCC analysis in the Urban Transit Vehicle, based on a internationl codes and standards related to LCC analysis. A main objective of the LCC analysis is to quantify the total cost of ownership of a product throughout its full life cycle, which includes research and development, construction, operation and maintenance, and disposal. The predicted LCC is useful information for decision making in purchasing a product, in optimizing design, in scheduling maintenance, or in planning overhaul. This paper presents a LCC procedure consisting of seven steps, which are "Problems definition", "Cost elements definition", "System modeling", "Data collection", "Cost profile development", "Evaluation", and "Verification". Sub-activities to be encompassed in the seven steps procedure are described.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.653-658
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• 2009

This paper describes the structural deflection analysis method and result of EMU(Electric Multiple Units). During manufacturing of rail passenger coaches, the underframe is assigned a camber before it is integrated with other major assemblies of shell such as the side panel, the end panel and the roof. The camber of the positive deflection given intentionally to compensate for the sagging so that it remains straight at the maximum load. But some manufacturers have insisted there has no relationship between the camber and the safety or life cycle and they expect to reduce a manufacturing cost without a camber. So this study analyzes whether the camber influences on the safety or life cycle of EMU structure under a full load and regular driving condition. The structural dynamics model for a railway vehicle is introduced.

• 시스템엔지니어링학술지
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• 제1권1호
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• pp.32-38
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• 2005

This paper presents the brief generation process of system requirements for Smart UAV from a development objective. The current Smat UAV requirements deal with the restricted life cycle from development to test and verification exclusive of full life cycle because of the new technology demonstration research program funded by governments. The Smart UAV system consists of flight vehicle, avionics, communication link, payload, ground control station and ground supporting system. In this paper, top-down flown requirements are introduced how to allocate to each sub-system.

• 대한조선학회논문집
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• 제43권2호
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• pp.213-219
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• 2006

Low cycle fatigue cracks are mainly detected at discontinuous welded locations with high stresses under repeated cyclic static loads due to cargo leading and unloading. Theoretical and analytical methods have been used for evaluation of local stress and strain which have an effect on a prediction of fatigue life, but those have difficulties of considering stress concentration at notched location and complicated material behavior of welded joint or heat affected zone. Electronic speckle pattern interferometry(ESPI) system is nondestructive and non-contact measurement system which can get the relatively accurate full field strain at critical positions such as welded zone and structural discontinuous location. In this study, local strain was measured on welded cruciform joint by ESPI system and then low cycle fatigue test was performed. Effect of local strain on low cycle fatigue life was examined by measured values using ESPI system. Moreover, experimental fatigue life was compared with established S-N curves using theoretical local strain and stress calculated by Neuber's rule.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.581-584
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• 2005

A district heating(DH) system supplies environmentally-friend heat and is appropriate for reduction of energy consumption and/or air pollutions. The objectives of this paper are to systematize data processing of transition temperature, investigate its effects on fatigue life of DH pipes and optimization for size of DH pipes. A relational database management system as well as reliable fatigue life evaluation procedures is established for Korean DH pipes. Also, since the prototypal evaluation results satisfied both cycle-based and stress-based fatigue criteria. Through the optimum design process, the cross section diminished 18.64% and the CUF diminished 23.35%. So, it can be used as useful information in the future for optimal design, operation and energy saving via setting of efficient condition and stabilization of water temperature.