• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.3
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• pp.68-73
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• 2014

Research is being carried out at Korea Aerospace Research Institute with aim of design a HALE UAV(High Altitude Long Endurance Unmanned Air Vehicle). HALE UAVs are ideally suited to provide surveillance, remote sensing and communication relay capabilities for both military and civilian applications. HALE UAVs typically cruise at an altitude between 15 km and 20 km, travelling at low speed and circling specific area of interest. Airframe structural point of view, weight reduction of the airframe structure is the most important method to improve the flight efficiency. High modulus CFRP(Carbon Fiber Reinforced Polymer) has been used in designing the structure in order to minimize the airframe weight. With respect to structural design and analysis, the key question is to decide an adequate airworthiness certification base to define suitable load cases for sizing of various structural components. In this study, FAR(Federal Aviation Regulation) 23 have constituted the guidance and benchmark throughout all structural studies. And the MSC/FlightLoads was introduced to analyze the flight loads for the HALE UAV. The MSC/FlightLoads can compute the flexible air load and analyzed loads are distributed on structural model directly. A preliminary structural concept was defined in accordance with the estimated inertial and aerodynamic loads. A FEM analysis was carried out using the MSC/Nastran code to predict the static and dynamic behaviour of UAV structure.

• STI Policy Review
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• v.1 no.1
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• pp.1-21
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• 2010

To achieve the "low carbon green growth" vision, the first step is securing core technologies. Therefore, S&T policy direction for green technology development is urgently needed. As of 2008, investment in green technology (GT) development hovered around 10% of the government's total R&D budget. Thus, the Korean government developed a plan to increase that percentage to 15%, by 2013. To develop reasonable investment strategies for green technology development, targeted strategies that reflect technology and market changes by green technology area are needed. However, the overall planning and coordination of national GT development is currently split among, approximately, 10 government ministries. To establish an efficient green technology development system, the so-called "Green Technology R&D Council" should be launched in collaboration with the Presidential Committee on Green Growth and the National Science and Technology Council. Furthermore, to build a solid foundation for commercializing the outcomes of GT development projects and promote GT transfer, the government should undertake two initiatives. First, the government should reinforce GT R&D performance management, by establishing a GT R&D performance management and evaluation system. Second, the government should implement the "customized packaged support for promoting green technology business rights and commercialization" and present "e-marketplace for market-oriented green technologies". Creating a pan-ministerial policy for GT development policy would necessitate restructuring the HR(Human Resources) development system, which is currently separated by technology area. Based upon mid/long-term HR supply and demand forecasts, the government should design differentiated HR development projects, continuously evaluate those projects, and reflect the evaluation results in future policy development. Finally, to create new GT-related industries, the "Green TCS (Testing, Certification, and Standards) System" needs to be implemented. For objective evaluation and diffusion of R&D results by green technology area, a common standardization plan for testing, analysis, and measurement, like the "Green TCS", should be developed and integrated.

• Korean Institute of Interior Design Journal
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• v.21 no.6
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• pp.212-223
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• 2012

The "Eco-friendly", "Green" concepts was began around 1992 after the Rio Environmental Summit, and the need for sustainable development globally widespread. The green building certification system was began around 2000 and the concept of green building was started in the late 1990s. The green building, which welcomes a period of radical change, is for the survival of the Earth "climate change" and reducing energy consumption in building sector. In this architecture of eco-friendly concept, the green building is rapidly expanding and existing as a ecological environment preservation. Moreover, the realization of zero energy house is to mandate for new buildings in 2025. The aim of further eco-friendly is through the prior ecosystems to restore and product energy for the 9 Green Building model houses in this paper. Building in the concept of ecology is to show about change into 7R's from the 3R's. The "Reduce", "Reuse", "Recycle" consisting of "3R's" is correlated with the traditional to the present Green Building Design. U.S. NCARB (National Council of Architectural Registration Boards) change into the concept of 7R's as "Receive", "Restore", "Respect" and "Remember", added to "3R's". In this paper, the 9 Green Building model houses do not meet the criteria of 7R's. But, the Green Tomorrow of Samsung C & T Corporation meet the 6 criteria for 7R's. This company is most comfortable at low carbon Green Building model houses. Conclusionally, introduction of eco-friendly technologies and amenities for the health of human and natural community life is to advance eco-friendly construction and enhance brand value of housing. By the way, The problem of eco-friendly architecture is initial investment and maintenance. Therefore, eco-friendly architecture and government has to try solving of this difficulty.

• Journal of Climate Change Research
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• v.9 no.2
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• pp.197-207
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• 2018

The Korean government views coal-fired power plants as the key cause of the fine dust generation, and is developing an energy policy to replace and demolish old coal-fired power plants. According to the Eighth Power Supply Base Plan (2017-2031), the maximum power capacity in 2030 is expected to be 100.5GW, which is 17.9% higher than the current level (85.2GW). The plan aims to reduce the facility size and power generation ratio from nuclear and coal resources to even lower levels than today, and to rapidly expand power generation from new and renewable energy. Despite that, the proportion of coal power generation is still much higher than other resources, and it is expected that the reliance on goal will maintain for next several decades. Under such circumstances, the development, supply, and expansion of clean coal technology (CCT) that is eco-friendly and highly efficient, is crucial to minimize the emission of pollutants such as carbon dioxide and fine dust, as well as maximize the energy efficiency. The Korean government designated the Yong-Dong Thermoelectric Power Plant in Gangneung to develop clean coal power generation, and executed related projects for three years. The current study aims to suggest a plan to develop parts, technologies, testing, evaluation, certification, and commercialization efforts for coal-fired power generation, In addition, the study proposes a strategy to vitalize local economy and connect the development with creation of more jobs.

• Journal of Aerospace System Engineering
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• v.16 no.3
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• pp.35-41
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• 2022

UAM (Urban Air Mobility) is a new safe, secure, and more sustainable air transportation system for passengers and cargo in urban environments. Commercial operations of UAM are expected to start in 2025. Since production rates of UAM are expected to be closer to cars than conventional aircraft, the airworthiness methodology for UAM must be prepared for mass production. Composite materials are expected to be mainly used for UAM structures to reduce weight. In this paper, the composite material qualification method was derived and the materials were applied for small aircraft application. It is expected to reduce the airworthiness certification time by applying composite material qualification system and its database.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.1097-1102
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• 2022

With the continuous development of the current industry, the current global environment is in a very serious situation, with resource supply and demand dependent on imports and huge costs for waste disposal due to the depletion of resources and mass generation of industrial waste. Its limitations have already been revealed in many fields, and the importance of re-manufacturing is drawing attention as a countermeasure to these problems. Re-manufacturing aims to recover products that are in the aging and disposal stages, recover to performance close to new products, and re-commercialize them. Among them, most of the machine tools are made of materials such as steel and cast iron with large structures, and raw materials are widely used when producing new products. In addition, since a lot of carbon is generated due to production, it is an object that can obtain a great re-manufacturing effect. Planner millers belonging to large machine tools are one of the machine tool equipment that can greatly reduce resources and energy through re-manufacturing because the structure is very large and the casting is several to tens of tons. Through this machine tool, performance tests and results are derived on the development of re-manufacturing source technology and domestic servo motor and CNC control device.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.477-483
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• 2013

The purpose of this study was to calculate uncertainty of emission factor collected data and to evaluate the applicability of Monte Carlo simulation technique. To estimate the distribution of emission factors (Such as Basic wood density, Biomass expansion factor, and Root-to-shoot ratio), four probability density functions (Normal, Lognormal, Gamma, and Weibull) were used. The two sample Kolmogorov-Smirnov test and cumulative density figure were used to compare the optimal probability density function. It was observed that the basic wood density showed the gamma distribution, the biomass expansion factor results the log-normal distribution, and root-shoot ratio showd the normal distribution for Pinus densiflora in the Gangwon region; the basic wood density was the normal distribution, the biomass expansion factor was the gamma distribution, and root-shoot ratio was the gamma distribution for Pinus densiflora in the central region, respectively. The uncertainty assessment of emission factor were upper 62.1%, lower -52.6% for Pinus densiflora in the Gangwon region and upper 43.9%, lower -34.5% for Pinus densiflora in the central region, respectively.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.327-332
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• 2021

Materials used for education include SM20C, Al6061, and acrylic. SM20C materials are used a lot in certification tests and functional competitions as carbon steel, but they are also used in industrial sites. Al6061 is said to be a material that produces a lot of tools because it has lower hardness than carbon steel and is highly flexible. When practical guidance is given to students using acrylic materials, it is a material that causes vibration and tool damage due to excessive cutting. In this process, we examine how impact on the 5-axis equipment 2NC head can affect precision control. The weakest part of a five-axis equipment is the head that controls the AC axis. In the event of precision and cumulative tolerances in this area, the precision of all products is reduced. Thus, a key part of the 2NC head, the spindle housing was carried out using Al7075 T6 (U.S. Alcoasa) material and the entire body using FCD450 (spherical graphite cast iron). In the vibration and cutting process acting on these two materials, the analysis was carried out to determine the value of applying the force as a finite element analysis under extreme conditions. We hope that using these analytical data will help students see and understand the structure of 5-axis machining rather than 5-axis cutting.

• Journal of Practical Engineering Education
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• v.14 no.1
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• pp.119-125
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• 2022

Materials used for education are materials such as SM20C, Al6061, and acrylic. SM20C materials are carbon steel and are often used in certification tests and functional competitions, but are also widely used in industrial sites. The Al6061 material is said to be a material that has lower hardness and stronger flexibility than carbon steel, so it is a material that generates a lot of compositional selection of tools. If students are taught practical training using acrylic materials, vibration occurs due to excessive cutting in some parts and damage to the tool occurs. In this process, we examine to what extent the impact on the 2NC head, which is a five-axis equipment, can affect precision control. The weakest part of the five-axis equipment can be said to be the weakest part of the head that controls the AC axis. When the accuracy and cumulative tolerance of this part occur, the accuracy of all products decreases. Therefore, the core part of the 2NC head, the spindle housing, was carried out using an Al7075 T6 (Alcoa, USA) material. In the process of vibration and cutting applied to this material, the analysis was conducted to find out the value applied to the finite element analysis under extreme conditions. It is hoped that this analysis data will help students see and understand the structure of 5-axis machining rather than 5-axis cutting.

• Journal of Korean Society of Forest Science
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• v.102 no.3
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• pp.420-427
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• 2013

This study was conducted to analyze growth characteristics and adaptability of poplar clones under the treatment of liquid pig manure. The average of survival rate was 33% better at control than the treatment under age of 5 years. But, tree height and DBH growth were higher at the treatment than control. Populus euramericana 'Eco28' showed the highest survival rate (97.9%) under the treatment. P. euramericana 'Eco28' and P. deltoides hybrid 'Dorskamp' could be selected as superior clones for height and DBH growth under the liquid pig manure treatment. The above-ground biomass production was also investigated when the poplar clones were 5 years old. The aboveground biomass under the liquid pig manure treatment was, on average. 52.6 ton/ha, which was 80% higher than control (29.1 ton/ha). P. euramericana 'Eco28' (73.6 ton/ha) and P. deltoides hybrid 'Dorskamp' (71.1 ton/ha) showed superior biomass production than other clones at the treatment of liquid pig manure. Based on survival, growth and demage traits, the adaptability of poplar clones to liquid pig manure treatment was estimated. P. deltoides hybrid 'Dorskamp' and P. euramericana 'Eco28' showed better adaptability to the treatment. P. nigra ${\times}$ P. maximowiczii '62-10' and P. koreana ${\times}$ P. nigra var. italic 'Suwon' were identified as poor adaptability clones.