• 공학교육연구
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• 제26권1호
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• pp.27-36
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• 2023

The purpose of this study was to investigate high school students' competencies of creativity thinking, critical thinking, communication, collaboration, and digital competence by implementing science fiction STEAM program. Based on the story of 'Fritz Haber' and the 'Garden of Dawn', a STEAM program was developed according to the ADDIE model. In the analysis stage, the purpose of the teaching-learning program using novels was set, and learners and learning environments were analyzed. At the design stage, the novels 'Fritz Harbor' and 'Garden of Dawn' were selected, learning goals were set according to the achievement standards of the curriculum, and learning contents and learning activities were sequenced and designed. In the development stage, teaching and learning materials were developed in a module format, implemented to classes, and evaluated. Pre-test and post-tests were conducted to identify the five major competencies such as creativity thinking, critical thinking, communication, collaboration, digital competence. The collected data was verified by paired t-test using SPSS. The results of the study showed statistically significant results in creative thinking, critical thinking, and digital competency.

• 대한토목학회논문집
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• 제28권3D호
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• pp.371-381
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• 2008

국내 하천시설물 건설공사는 도로 등의 다른 토목시설공사에 비해서 사업의 금액규모가 상대적으로 작다는 등의 특성으로 인해 사업의 기획 및 계획단계에서의 개략적인 공사비용을 예측하는 기준 단가가 정립되어 있지 않으며, 시설물의 특성을 고려한 합리적이고 체계적인 견적 방법론 또한 존재하지 않는다는 문제점을 가지고 있다. 본 연구는 하천시설물 건설공사의 실적자료를 수집하고 분석하여, 4단계로 이루어진 하천 제방공사 실적정보 구성 체계를 제시하고, 공사비에 영향을 끼치는 인자들을 주요 공종별로 도출하여, 하천시설물 공사의 기획단계에서 적정한 개략공사비를 산정하는 체계적인 방법론을 제시한다.

• 한국태양에너지학회 논문집
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• 제36권2호
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• pp.19-29
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• 2016

Whilst there are growing interests in pursuing energy efficiency and zero-energy buildings in built environment, it is widely recognised that Building-Integrated Photovoltaic (BIPV) is one of the most promising and required technologies to achieve these goals in recent years. Although BIPV is a broadly utilized technique in variety of fields in built environments, it is required that generation of BIVP should be analysed and calculated by external specialists. The aim of this research is to focus on developing a new diagram for prediction of the pre-estimation model in early design stage to harness solar radiation data, PV types, slopes, azimuth and so forth. The results of this study show as follows: 1) We analysed 162 districts in a national level and the examined areas were categorised into five zones. The standard deviation of the results was 2.9 per cent; 2) The increased value of solar radiation on a vertical plane in five categorised zones was 42kWh/m3, and the result was similar to the average value of 43.8kWh/m3; and 3) The pre-estimation of diagram was developed based on the categorisation of zones and azimuth as well as the results of the developed diagram showed little difference compared to the previously utilised method. The suggested diagram in this paper will contribute to estimate BIPV without any external contribution to calculate the value. Even though the result of this study shows little difference, it is required to investigate a number of different variables such as BIPV types, modules, slope angle and so forth in order to develop an integrated pre-estimation diagram.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.114-117
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• 2004

The isothermal forging design of a Ti-6Al-4V wing shape was performed by 3D FE simulation. The design focuses on near-net shape forming by the single stage. The process variables such as the die design, pre-form shape and size, ram speed and forging temperature were investigated. The minimization of forging load and uniform strain distribution in a given forging condition were considered as main design factors. The FE simulation results fur the final process design were compared with the isothermal forging tests. Finally, the modified process design for producing the uniform Ti-6Al-4V wing product without forming defects was suggested.

• 소성∙가공
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• 제14권2호
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• pp.126-132
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• 2005

The isothermal forging design of a Ti-6Al-4V wing shape was performed by 3D FE simulation. The design focuses on near-net shape forming by the single stage. The process variables such as the die design, pre-form shape and size, ram speed and forging temperature were investigated. The main design priorities were to minimize forging loads and to distribute strain uniformly in a given forging condition. The FE simulation results for the final process design were compared with the isothermal forging tests. The instability of deformation was evaluated using a processing map based on the dynamic materials model(DMM), including flow stability criteria. Finally, a modified process design for producing a uniform Ti-6Al-4V wing product without forming defects was suggested.

• 한국정밀공학회지
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• 제21권9호
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• pp.85-94
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• 2004

As over 70% of the total life cycle cost (LCC) of a product is committed at the early design stage, designers are in an important position to substantially reduce the LCC of the products they design by giving due to life cycle implications of their design decisions. During early design stages, there may be competing concepts with dramatic differences. In addition, the detailed information is scarce and decisions must be made quickly. Thus, both the overhead in developing parametric LCC models fur a wide range of concepts, and the lack of detailed information make the application of traditional LCC models impractical. A different approach is needed, because a traditional LCC method is to be incorporated in the very early design stages. This paper explores an approximate method for providing the preliminary LCC, Learning algorithms trained to use the known characteristics of existing products might allow the LCC of new products to be approximated quickly during the conceptual design phase without the overhead of defining new LCC models. Artificial neural networks are trained to generalize product attributes and LCC data from pre-existing LCC studies. Then the product designers query the trained artificial model with new high-level product attribute data to quickly obtain an LCC for a new product concept. Foundations fur the learning LCC approach are established, and then an application is provided.

• 대한기계학회논문집A
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• 제22권4호
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• pp.731-742
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• 1998

Bolted opening structures is widely applied for class 1 machinery of nuclear plant with strict design requirement. As the shape of the bolted opening structure is non-axisymmetric due to the existence of stud bolts although it is almost axi-symmetric, 3D analysis is required to satisfy such kind of design requirements. Because as much as possible trial computations are need to get an optimal design condition in the limited period of basic design, an easy and fast analysis tool is useful in the design stage. In the paper, a transformation technique of non-axisymmetric problem into quasi-axisymmetric has been proposed based on the general purpose commercial code ANSYS. Both the pre-processor which incorporates the technique and prepares data and post-processor which prepares arranged results from the huge output of commercial code have been developed to help the design engineers.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.86-92
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• 2008

Recently, the use of tubes in the manufacturing of the automobile parts has increased and therefore many automotive manufactures have tried to use hydro-forming technology. The hydro-forming technology may cause many advantages to automotive applications in terms of better structural integrity of the parts, lower cost from fewer part count, material saving, weight reduction, lower spring-back, improved strength and durability and design flexibility. In this study, the whole process of front engine cradle (or front sub-frame) parts development by tube hydro-forming using steel material having tensile strength of 440MPa grade is presented. At the part design stage, it requires feasibility study and process design aided by CAE (Computer Aided Design) to confirm hydro-formability in details. Effects of parameters such as internal pressure, axial feeding and geometry shape on automotive sub-frame by hydro-forming process were carefully investigated. Overall possibility of hydro-formable sub-frame parts could be examined by cross sectional analyses. Moreover, it is essential to ensure the formability of tube material on every forming step such as pre-bending, preforming and hydro-forming. At the die design stage, all the components of prototyping tools are designed and interference with press is examined from the point of geometry and thinning.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.131-133
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• 2007

In a design of DC ballast for fluorescent lamp, pre-stage of DC-DC converter is required to keep the constant output lumen performance regardless of variable DC input voltage. In this paper, flyback topology is used for optimum performance of 32W lamp, and various important design points for successful operation over the whole operating range are described.

• 한국자동차공학회논문집
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• 제6권5호
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• pp.146-152
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• 1998

Recently, for the development of vehicle structures and components there is a tendency to increase using numerical simulation methods compared with practical tests for the estimation of the fatigue strength. In this study, an integrated powerful methodology is suggested for fatigue strength evaluation through development of the interface program to integrate dynamic analysis quasi-static stress analysis and fatigue analysis, which were so far used independently. To verify the presented evaluation method, a single and zigzag bump run test, 4-post road load simulation and driving durability test have been performed. The prediction results show a good agreement between analysis and test. This research indicates that the integrated life prediction methodology can be used as a reliable design tool in the pre-prototype and prototype development stage, to reduce the expense and time of design iteration.