• 한국측량학회지
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• 제35권6호
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• pp.545-552
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• 2017

풍성사구는 지표, 바람과 식생간의 상호 작용에 의해 유지${\cdot}$발달되는 대표적인 사구이다. 이러한 사구의 변형을 예측하는 모형을 개발하는 것은 토지 황폐화와 같은 지형 경광의 이해와 관리의 효율성을 높이는데 매우 중요하다. 하지만 기존의 모형에서는 사구의 장기 거동에 대한 연구와 이를 이용한 실제 지형 적용에 관한 연구는 미비한 실정이다. 따라서, 본 연구에서는 식생을 고려한 바람-식생 모형을 실제 지형에 적용하고, 장기 거동을 실제 데이터와 비교하여 바람-식생 모형의 적용성을 분석하였다. 분석을 통해서 바람-식생 모형과 무인항공기 데이터를 이용하는 방법이 경계면을 제외하고 실제 사구지형의 변화와 최대 1m 내외의 오차로 나타나 장기 거동 분석에 효과적인것을 알 수 있었다.

• 대한교통학회지
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• 제27권3호
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• pp.29-38
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• 2009

우리나라는 1970년대 이후 시행된 도시계획사업을 통해 도시지역에 대규모 주택단지 및 주거지역이 나타나기 시작하였다. 그리고 개발된 지역에서는 공동주택의 비율이 점차 증가하는 경향이 나타나면서 도로변공동주택의 도로교통소음이 새로운 문제로 대두되었다. 그리고 1980년대 후반이후 공동주택은 15층에 머물던 공동주택은 20-30층의 초고층의 형태로 변모하였고, 최근에는 40층 이상의 공동주택이 등장하면서 도시지역의 주거밀도는 더욱 고밀화 되면서 이로 인하여 도로교통소음은 더욱 증가하게 되었다. 이에 본 연구는 도로변에 위치한 공동주택에 영향을 주는 인자 중 교통량, 통과속도를 변수로 하여 소음지도를 구축하여 저감효율에 대해 살펴보았다. 결과는 교통량과 속도제한의 증감에 따른 변화는 한정된 공간에 영향을 주는 것으로 나타났으며, 버스중앙차로제는 도로변에 약간의 영향만을 미치는 것으로 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.800-807
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• 2010

In this study, a series of numerical analyses has been performed in order to evaluate the performance of a full-scale closed-loop vertical ground heat exchanger constructed in Wonju. The circulation pipe HDPE, borehole and surrounding ground were modeled using FLUENT, a finite-volume method (FVM) program, for analyzing the heat transfer process of the system. Two user-defined functions (UDFs) accounting for the difference in the temperatures of the circulating inflow and outflow water and the change of the surrounding ground temperature with depth were adopted in the FLUENT model. The thermal properties of materials estimated in laboratory were used in the numerical analyses to compare the thermal efficiency of the cement grout with that of the bentonite grout used in the construction. The results of the simulation provide a verification of the in situ thermal response test data. The numerical model with the ground thermal conductivity of 4W/mK yielded the simulation result closer to the in-situ thermal response test than with the ground thermal conductivity of 3W/mK. From the results of the numerical analyses, the effective thermal conductivities of the cement and bentonite grouts were obtained to be 3.32W/mK and 2.99 W/mK, respectively.

• 복식
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• 제61권5호
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• pp.1-20
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• 2011

As a follow-up of a study on design strategies to improve Korea's Korean coast guarduniforms, this study set out to propose Korean coast guard uniforms of a new concept that would meet the changing needs of the times and match the advanced technology and work environments. Three concepts of classical, nautical and techno chic were identified from the design strategies of the previous study. Using the results from a prototype show and preference survey, the investigator divided items into design, color, material, and detail and reflects demands for each of them. As a result, design was examined in four aspects of identity, acknowledgement, unity, and practicality and focused its improvement factors on design differentiated from other organizations' uniforms including ground police, segmentation of size system, adjustment of the length of upper garment to consider activity, and changes to the lines and silhouette to give out a modern image. As for color, the focus was placed on differentiated colors from other organizations' uniforms including ground police through dark blue and ocean color, change toward colors that reflect environmental characteristics, and unity in colors between the summer and winter uniform. As for material, the focus of improvement was put on elasticity, resistance against contamination, warmth retention, texture, wearing sensation, and functionality by taking into account convenience for field workers on coast guard vessels and branch offices who have much time in contact with ocean environments in order to make the materials high-grade. As for detail, structural details were added to give out a modern image such as changing the detail lines, efficiency of storage space, buttons, sleeve hems, ironing lines, and neck collars by taking into account environmental characteristics. The significance of the study lies in that it proposed a development model for large-scale uniform copy design by establishing copy design that secures functionality and is proper for an organization's social and cultural environment.

• Journal of Microbiology and Biotechnology
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• 제25권9호
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• pp.1547-1554
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• 2015

The potential of microalgae biofuel has not been realized because of the low productivity and high costs associated with the current cultivation systems. In this study, a new low-cost and transparent attachment material was tested for cultivation of a filamentous algal strain, Stigeoclonium sp., isolated from wastewater. Initially, the different materials tested for Stigeoclonium cultivation in untreated wastewater were nylon mesh, polyethylene mesh, polypropylene bundle (PB), polycarbonate plate, and viscose rayon. Among the materials tested, PB led to a firm attachment, high biomass (53.22 g/m², dry cell weight), and total lipid yield (5.8 g/m²) with no perceivable change in FAME profile. The Stigeoclonium-dominated biofilm consisted of bacteria and extracellular polysaccharide, which helped in biofilm formation and for effective wastewater treatment (viz., removal efficiency of total nitrogen and total phosphorus corresponded to ~38% and ~90%, respectively). PB also demonstrated high yields under multilayered cultivation in a single reactor treating wastewater. Hence, this system has several advantages over traditional suspended and attached systems, with possibility of increasing areal productivity three times using Stigeoclonium sp. Therefore, multilayered attached growth algal cultivation systems seem to be the future cultivation model for large-scale biodiesel production and wastewater treatment.

• Wind and Structures
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• 제21권6호
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• pp.693-707
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• 2015

The efficiency of wind turbines (WT) is primarily reflected in their ability to generate electricity at any time. Downtimes of WTs due to "conventional" inspections are cost-intensive and undesirable for investors. For this reason, there is a need for structural health monitoring (SHM) systems, to enable service and maintenance on demand and to increase the inspection intervals. In general, monitoring increases the cost effectiveness of WTs. This publication concentrates on the application of two vibration-based SHM algorithms for stability and structural change monitoring of offshore WTs. Only data driven, output-only algorithms based on stochastic subspace identification (SSI) in time domain are considered. The centerpiece of this paper deals with the rough mathematical description of the dynamic behavior of offshore WTs and with the basic presentation of stochastic subspace-based algorithms and their application to these structures. Due to the early stage of the industrial application of SHM on offshore WT on the one side and the required confidentiality to the plant manufacturer and operator on the other side, up to now it is not possible to analyze different isolated structural damages resp. changes in a systematic manner, directly by means of in-situ measurement and to make these "acknowledgements" publicly available. For this reason, the sensitivity of the methods for monitoring purposes are demonstrated through their application on long time measurements from a 1:10 large scale test rig of an offshore WT under different conditions: undamaged, different levels of loosened bolt connections between tower parts, different levels of fouling, scouring and structure inclination. The limitation and further requirements for the approaches and their applicability on real foundations are discussed along the paper.

• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1494-1500
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• 2012

Fermentation with filamentous fungi in a bioreactor is a complex dynamic process that is affected by flow conditions and the evolution of the rheological properties of the medium. These properties are mainly affected by the biomass concentration and the morphology of the fungus. In this work, the rheological properties of a fermentation with the fungus Beauveria bassiana under different hydrodynamic conditions were studied and the rheological behavior of this broth was simulated through a mixture of carboxymethyl cellulose sodium and cellulose fibers (CMCNa-SF). The bioreactor was a 10 L CSTR tank operated at different stir velocities. Rheological results were similar at 100 and 300 rpm for both systems. However, there was a significant increase in the viscosity accompanied by a change in the consistence index, calculated according to the power law model, for both systems at 800 rpm. The systems exhibited shear-thinning behavior at all stir velocities, which was determined with the power law model. The mixing time was observed to increase as the cellulose content in the system increased and, consequently, the efficiency of mixing diminished. These results are thought to be due to the rheological and morphological similarities of the two fungal systems. These results will help in the optimization of scale-up production of these fungi.

• 한국수소및신에너지학회논문집
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• 제24권6호
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• pp.535-542
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• 2013

To enhance the performance of SEWGS system by holding the WGS catalyst in a SEWGS reactor using bed inserts, effect of bed insert geometry on CO conversion of WGS catalyst was measured and investigated. Small scale fluidized bed reactor was used as experimental apparatus and tablet shaped WGS catalyst and sand particle were used as bed materials. The cylinder type and the spring type bed inserts were used to hold the WGS catalysts. The CO conversion of WGS catalyst with the change of steam/CO ratio was determined based on the exit gas analysis. Moreover, gas flow direction was confirmed by bed pressure drop measurement for each case. The measured CO conversion using the bed inserts showed high value comparable to previous results even though at low catalyst content. Most of input gas flowed through the bed center side when we charged tablet type catalyst into the cylinder type bed insert and this can cause low $CO_2$ capture efficiency because the possibility of contact between input gas and $CO_2$ absorbent is low in this case. However, the spring type bed insert showed good reactivity and good distribution of gas, and therefore, the spring type bed insert was selected as the best bed insert for SEWGS process.

• 한국실내디자인학회논문집
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• 제6호
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• pp.45-52
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• 1995

The presentation of the method by which the furniture and the architecture can be unified in one category, and the study and the verification on the mutual relation in the shape and the function are having been consistently made till the late twenties. The change of the social structure such as increasing the unit dwelling space with the small scale comes to need the efficiency in using space and the open dwelling space by the systematic spa-cial formation. Therefore, the understanding of the mean-ing and the characteristics of system furnitures as the design method which can meet such needs will be made here in this study. The application of the systematic consideration as the method of interior design means the formation of the firm image on the spacial environment through the mix-ture and link of the heterogeneous factors, the organic connection of each surface, the establishment of the natu-ral relation by linking the heterogeneous materials mutu-ally. and the easiness of the entire plan in the end. This study aims at analyzing and studying the typical charac-teristics by understanding the historical background and methodical principle which enabled the appearance of this kind of thought, and the adapted cases of the wood and metal material system furniture. There may be difference between the structural sub-stance and formative consideration. Transformative furni-ture which consists of the factors is the concept for the encrease of the multi purpose value by mixing the unit cabinets. One system can be separated horizontally, verti-cally, and to the drawers, and it gives us the disengage-ment from the artificial environment, since all the heights and width can be transformed as per each situa-tion of the space. The factors which can not be found in the other existing furniture are as follows. 1. disengagement from the artificial environment. 2. establishing the new productiosn trend as freed from the customers' fashion trend. 3. presenting the producing condition which leads the exact technology. 4. flexibility of the furniture which enables the reduction and enlargement in each situation.

• 한국유통학회지:유통연구
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• 제2권2호
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• pp.153-172
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• 1997

The distribution sector is affected by a wide range of regulations. Many of these are related to health and safety, others are related to urban planning and environmental issues, whereas some mainly have an economic basis. But, regulations many be unduly restrictive, in which case they can drive up costs and ultimately prices, or they may, in some cases, reduce consumer choice. Unduly restrictive regulations could also increase costs indirectly, by reducing competition and thus lead to lower productivity growth. In the past few years, distribution sector has gone through drastic changes due to deregulation and market opening. Implementation of regulatory reforms served as an opportunity to change laws and systems which had been an obstacle to development of distribution sector. Market opening of distribution sector became a turning point to promote competition among domestic and foreign firms. However, for small and medium scale of the typical retail enterprises which were in no position to compete in terms of prices, additional facilities, and services, faced a threat of diminished trading area, and even of their existence. Because, large firms may have greater market power than small firms, as they can more easily extract favorable terms when procuring goods, and may also be able to deter entry by advertising outlays or access to the best sites. In addition, larger chain stores armied with sufficient capital dominated trading area and reduced customer's welfare by abusing their monopoly power when competing with other shops, and are often cited as an example of adverse effects of local monopoly. In order to minimize such adverse effects and to foster competition, regulatory reforms in distribution sector should set its goal to promote sound and stable distribution activities through market principle and restoring competition principle, and ultimately to boost customers welfare. Therefore, deregulation in distribution sector should be implemented in a way to promote customers welfare, eliminate entry barriers, and expand competition principle such as productivity and efficiency competition. However, it should be also recognized that deregulation of system alone is not enough to develop the distribution sector. To compete in a increasingly concentrated industry, small enterprises increasingly engage in co-operative arrangements, such as buying groups, strategic alliances or franchise agreements.