• Transactions of the Korean hydrogen and new energy society
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• v.16 no.3
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• pp.296-305
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• 2005

최근 수소에너지가 환경문제를 해결해 줄 수 있는 대체에너지로 각광받으면서 수소에너지의 사용이 가지고 올 새로운 에너지 체제에 대한 시나리오 연구가 다양하게 수행되고 있다. 수소 기술-경제체제의 가능한 시나리오를 제시하는 것은 미래 사회에서 수소가 에너지 운반체로서 담당하게 될 역할을 명확히 할 수 있음과 동시에 에너지라는 거대한 기술-경제체제의 변화를 위해 현재 수행해야 할 에너지 정책과 전략에 대해 큰 시사점을 줄 수 있기에 의미가 있다. 본 연구는 수소의 생산, 저장 및 운반, 그리고 응용분야에서의 다양한 기술의 SWOT 분석을 통해 가능한 시나리오를 단기와 장기로 나누어 제시했다. 그 결과 앞으로의 수소 기술-경제체제의 구조는 기술적 완성도 뿐 아니라 사회적 수용성, 사회적 적응성 등 외부의 환경변화에도 많은 영향을 받음을 알았다. 그렇기 때문에 수소에너지에 관한 전략과 정책은 이러한 변동을 충분히 고려하면서 결정돼야 한다.

• Journal of Science and Technology Studies
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• v.7 no.1
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• pp.5-31
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• 2007

In the catchup stages of technological development, the technology being pursued was well known. The fact that the technology is developable was known, and the fact that it should observe certain design is also known to developers. Therefore the technological and societal uncertainties have been relatively low. Comparatively, in the post-catchup stages of technological development, it is hard to predict if a certain technology is developable at all. And even though it is developable, in many cases the role models to which developers can refer to do not exist. This creates heavy uncertainties in both technological and societal regime. As a result, we need new strategical approaches to deal with the uncertainties that post-catchup technologies co-create. In this paper, we first define the core strategies of managing the techno-economic uncertainties as following: (1) how to deal with technological uncertainties, (2) how to acquire the justification and robustness of new technology. Then new conceptual frameworks to deal with those factors will be suggested.

• Computers and Concrete
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• v.27 no.4
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• pp.333-341
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• 2021

Steel slag, an industrial reject from the steel rolling process, has been identified as one of the suitable, environmentally friendly materials for concrete production. Given that the coarse aggregate portion represents about 70% of concrete constituents, other economic approaches have been found in the use of alternative materials such as steel slag in concrete. Unfortunately, a standard framework for its application is still lacking. Therefore, this study proposed functional model equations for the determination of strength properties (compression and splitting tensile) of steel slag aggregate concrete (SSAC), using gene expression programming (GEP). The study, in the experimental phase, utilized steel slag as a partial replacement of crushed rock, in steps 20%, 40%, 60%, 80%, and 100%, respectively. The predictor variables included in the analysis were cement, sand, granite, steel slag, water/cement ratio, and curing regime (age). For the model development, 60-75% of the dataset was used as the training set, while the remaining data was used for testing the model. Empirical results illustrate that steel aggregate could be used up to 100% replacement of conventional aggregate, while also yielding comparable results as the latter. The GEP-based functional relations were tested statistically. The minimum absolute percentage error (MAPE), and root mean square error (RMSE) for compressive strength are 6.9 and 1.4, and 12.52 and 0.91 for the train and test datasets, respectively. With the consistency of both the training and testing datasets, the model has shown a strong capacity to predict the strength properties of SSAC. The results showed that the proposed model equations are reliably suitable for estimating SSAC strength properties. The GEP-based formula is relatively simple and useful for pre-design applications.