• Transactions of the Korean hydrogen and new energy society
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• v.34 no.6
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• pp.575-580
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• 2023

An electrode was prepared by dip-coating NiFe₂O₄ powder on stainless steel (SUS) support for the application in the alkaline water electrolysis. The prepared electrode was analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS), and was evaluated for the voltage properties with the change of current density in oxygen evolution reaction (OER) and hydrgen evolution reaction (HER) using 1, 3 and 7 M KOH solution. From the SEM and EDXS analysis, it was confirmed that the prepared electrode had NiFe₂O₄ on the SUS support. In OER and HER, the voltage in the 7 M KOH solution had a value of 1.35 and -1.90 V at 0.2 and -0.2 A/cm² of the current density, respectively. It was considered that the prepared electrode could be use as an electrode in the alkaline water electrolysis from the experimental results.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.8-16
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• 2004

The industrialization of central Europe more than 100 ago marked the beginning of densely concentrated buildings in quickly growing cities. A cheap type of roofing material of that time was tar. But it was dangerous because it was high inflammable. Then some roofer had a splendid idea. They used sandy material as a final layer atop the impermeable tar layer. These roofs were much more fire resistant than the typical roofs. In this sandy layer some plant species began to grow spontaneously. This was the beginning of the green roof history of modern Europe. A number of these green roofs survived both world wars. In the early 80's in Berlin alone, 50 such buildings existed and they continued to be waterproof until the present day. Since the 1992 Earth Summit of 1992 in Rio de Janeiro(http://www.johannesburgsummit.org/html/basic_info/unced.html) the term "sustainable development" became of central interest of urban designers. In city regions green roofs had become synonymous with this term. With a small investment, long-lasting roofs can be created. Further back in history, more exciting examples of green roofs can be found. The hanging gardens of antiquity are well-known. There are also green roofs built as insulation against cold and heat all over the world. For over 20 years, roof greening in central Europe has been closely examined for various reasons. Roof greening touches several different disciplines. Of primary interest is the durability of the roofs. But ecologists are also interested in green roofs, for instance in biodiversity research. The beneficial effect of greening on water proofing was also proven. For some time, the issue of fire protection was investigated. According to tests, green roofs received a harsh careful rating. Their fire protective property is considered similar to that of tile roofs. Another recent impulse for the green roof movement in Germany has come from the evident improvement of storm water retention and the reduced burden on the sewer system. The question of whether and how much energy green roofs can save has become an urgent question. The state of the research and also various open questions from a central European point of view will be discussed in the context of international collaboration. Apart from academic considerations, those who involve themselves in this issue take a predominantly positive view of the numerous existing green roofs in Germany. In some cities, green roofs are the typical construction technique for new buildings. A few outstanding examples will conclude this review. In Germany, about 20 companies, some of which operate internationally, specialize in green roof consulting. Learning from each other in an open-ended way with respect to different construction techniques and applications in various climatic regions can only be accomplished through such international collaboration as is taking place here.

• Journal of Ecology and Environment
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• v.36 no.4
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• pp.303-314
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• 2013

The present study summarized the occurrence, distribution and autecology about 31 taxa of the green algae (Chlorophytes) collected from several swamps, reservoir and highland wet-lands in the South Korea from 2010 to 2013. This paper deals with a total 31 taxa including of 26 genera which are recorded for the first time in Korea. Among these algae, 18 genera including Pyrobotrys Arnoldi, Volvulina Playfair, Dicellula Svirenko, Echinocoleum Jao & Lee, Hofmania Chodat, Gloeotila Kutzing, Tetrachlorella Korschikov, Botryospherella P.C.Silva etc., were newly recorded in Korean fresh-water algal flora.

• Korean Institute of Interior Design Journal
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• v.13 no.4
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• pp.92-101
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• 2004

A rational and logical sense of design often found in modernism(including minimalism) sometime deal with the criticism that such characteristics which derived from those of modernism, lack emotion31 qualities(arises from human feelings). It consequently took them to adopt traditional designs in the past, creating such conditions that constantly escapes from‘present’ one and back to the‘new’. This mode develops a trend in current interior design which decorative elements such as art work: traditional arts, folk crafts, flowers and green are much evident. Thus, using many decorative elements of the past(what was once banned since modernism), brings up the interesting point of view that needs to be discussed a new decorative trend if today's interior design. It will approach by comparing significances of past decorative expressions with present through which investigation, will show a better understanding of recent characteristics in interior designing, a.k.a, a current trend since minimalism, embracing important qualities of culture, ecology and people - against today's less-inspired, standardizing spaces.

• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.681-688
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• 2020

The telegrapher's theory was used to develop a new formulation for the neutron noise equation. Telegrapher's equation is supposed to demonstrate a more realistic approximation for neutron transport phenomena, especially in comparison to the diffusion theory. The physics behind such equation implies that the signal propagation speed is finite, instead of the infinite as in the case of ordinary diffusion. This paper presents the theory and results of the development of a new method for calculation of the neutron noise using the telegrapher's equation as its basis. In order to investigate the differences and strengths of the new method against the diffusion based neutron noise, a comparison was done between the behaviors of two methods. The neutron noise based on SN transport considered as a precision measuring point. The Green's function technique was used to calculate the neutron noise based on telegrapher's and diffusion methods as well as the transport. The amplitude and phase of Green's function associated with the properties of the medium and frequency of the noise source were obtained and their behavior was compared to the results of the transport. It was observed, the differences in some cases might be considerable. The effective speed of propagation for the noise perturbations were evaluated accordingly, resulting in considerable deviations in some cases.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.5
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• pp.79-96
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• 2021

Green infrastructure planning represents landscape planning measures to reduce particulate matter. This study aimed to derive factors that may be used in planning green infrastructure for particulate matter reduction using text mining techniques. A range of analyses were carried out by focusing on keywords such as 'particulate matter reduction plan' and 'green infrastructure planning elements'. The analyses included Term Frequency-Inverse Document Frequency (TF-IDF) analysis, centrality analysis, related word analysis, and topic modeling analysis. These analyses were carried out via text mining by collecting information on previous related research, policy reports, and laws. Initially, TF-IDF analysis results were used to classify major keywords relating to particulate matter and green infrastructure into three groups: (1) environmental issues (e.g., particulate matter, environment, carbon, and atmosphere), target spaces (e.g., urban, park, and local green space), and application methods (e.g., analysis, planning, evaluation, development, ecological aspect, policy management, technology, and resilience). Second, the centrality analysis results were found to be similar to those of TF-IDF; it was confirmed that the central connectors to the major keywords were 'Green New Deal' and 'Vacant land'. The results from the analysis of related words verified that planning green infrastructure for particulate matter reduction required planning forests and ventilation corridors. Additionally, moisture must be considered for microclimate control. It was also confirmed that utilizing vacant space, establishing mixed forests, introducing particulate matter reduction technology, and understanding the system may be important for the effective planning of green infrastructure. Topic analysis was used to classify the planning elements of green infrastructure based on ecological, technological, and social functions. The planning elements of ecological function were classified into morphological (e.g., urban forest, green space, wall greening) and functional aspects (e.g., climate control, carbon storage and absorption, provision of habitats, and biodiversity for wildlife). The planning elements of technical function were classified into various themes, including the disaster prevention functions of green infrastructure, buffer effects, stormwater management, water purification, and energy reduction. The planning elements of the social function were classified into themes such as community function, improving the health of users, and scenery improvement. These results suggest that green infrastructure planning for particulate matter reduction requires approaches related to key concepts, such as resilience and sustainability. In particular, there is a need to apply green infrastructure planning elements in order to reduce exposure to particulate matter.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.2
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• pp.126-138
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• 2012

The purpose of this study is to evaluate the imbalance of green space using various spatial analysis methods and to establish the management zone for green space with service supply in the aspect of its use in Daegu. The total green space of Daegu is 48,936.1ha which is the second among 7 metropolitan cities of Korea. According to the imbalance analysis of green space, the Gini's coefficient based on the area was not high, on the other hand, the Gini's coefficient based on the population was high by above 0.6. According to an evaluation of service supply of green space in Dalseo-gu, the area within about 100m around large green space was supplied with green spaces of above $25m^2$/pop. On the other hand, the area such as Sangin, Jukjeon, and Yongsan was not almost supplied with green space. Finally, 'Rich zone', 'Fair zone', 'Poor zone', and Broken zone' could be established based on the service supply for the management direction of green space. The findings from this study can be used as the basic data for selecting the construction priority of new green spaces.

• Korean Journal of Construction Engineering and Management
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• v.13 no.2
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• pp.25-36
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• 2012

As the international construction market is rapidly expanding, Korean contractors have the need for having new leading businesses for their sustainable growth and high performance. Thus, this research tried to explore new leading businesses with two questions: 'What can be the new leading businesses?' and 'How can Korean contractors implement new leading businesses?' To this end, based on Porter's five forces framework and the resource-based view (RBV), we first derive three evaluation criteria (possibility of market entry, possibility of profit earning, and possibility of value-added earning). Next, we developed a framework for business evaluation which considers external market condition, internal competitiveness, and spin-off effects toward domestic market. Based on the framework, we defined green-energy plant, environmental plant, desalination plant, nuclear power plant, new urban development, and high-rise building as new leading business. Then, we selected green energy plant, environmental plant, and new urban development for the purpose of prior occupation of the market, consolidation of the competitiveness, and expansion of the ripple effect, respectively. Finally, we deduced market entry strategies for each business by investigating experts' opinions.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.986-989
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• 2002

This paper proposes a new single stage power factor correction (PFC) full bridge converter which operates at continuous conduction mode(CCM). The proposed single stage PFC consists of typical zero voltage switching(ZVS) full bridge DC/DC converter, two transformer auxiliary windings, and two small inductors, and two diodes. Neither additional active switch nor any control circuit are added for PFC resulting in very low cost. The proposed converter provides input power factor correction with CCM control and tight output voltage regulation. All switching devices are operated under ZVS with minimum voltage stress. Operation principle and analysis are explained and verified with computer simulation and experimental results on a 1.2kW, 100kHz prototype.

• Journal of Forest and Environmental Science
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• v.28 no.1
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• pp.19-23
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• 2012

Recently the Korean government provided forest recreation areas through developing evaluation index of rural areas amenity resources, forest therapy and recreational forest for revitalization of rural areas and national health promotion. However, what the public wants is just one place which includes all recreational facilities. GRAT tourism means Green, Rest and Therapy-Tourism. It is a new concept of recreational forests. This study defines GRAT-Tourism, the new concept of recreational activity and discusses the development of the GRAT-Tourism Evaluation Index.