• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.31-35
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• 2017

The internal flow of a pump system that is installed in the interior of large vessels such as tankers is largely affected by the water level and flow conditions of the pump sump. However, the performance of the pump is generally evaluated with the consideration of only the performance of the pump itself, without considering the pumping station operating environment. Therefore, if the pump is affected by the incoming flow that exhibits vortex and swirl, the occurrence of vortex and swirl accompanied with air may cause problems with the pump sump. This effect of flow condition can lead to a decrease in efficiency, increase in vibration, and noise generation in the pump. In this study, to investigate the internal flow of the pump sump according to several water levels, a pump sump scale-model was designed and constructed. The frequency of vortex occurrence and the shape of the vortex were investigated according to the different water levels of a fundamental test. The Class C vortex type, which has a larger volume of air intake to the pump, was confirmed by the higher occurrence frequency at a relatively lower water level.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.502-507
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• 2013

In this paper, a circular dual mode horn with modified aperture is proposed to improve a E/H-plane radiation pattern symmetry of a conventional oversized circular dual mode horn. The proposed antenna consists of a feeding section, a mode generation section and a phase matching section which has aperture shape transition from circle to ellipse or rectangle to improve a E/H-plane radiation pattern symmetry. To compare the performances between the proposed antenna and the convenional circular dual mode horn, the conventional circular dual mode horn and the proposed circular dual mode horn with rectangular aperture are fabricated and researched at 15 GHz. The measured results show that the conventional circular dual mode horn has 3.394 dB difference while the proposed antenna has only 0.539 dB difference between E and H-plane radiation patterns within the -11 dB beamwidth($53^{\circ}$) which is required beamwidth of the feed horn for the maximum aperture efficiency where f/d ratio of reflector antenna is 1.

• The KIPS Transactions:PartA
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• v.10A no.6
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• pp.665-670
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• 2003

In the applications like automatic masks generation for semiconductor production, a drawing consists of lots of polygons that are partitioned into trapezoids. The addition/deletion of a polygon to/from the drawing is performed through geometric operations such as insertion, deletion, and search of trapezoids. Depending on partitioning algorithm being used, a polygon can be partitioned differently in terms of shape, size, and so on. So, It's necessary to invent some comparison algorithm of sets of trapezoids in which each set represents interested parts of a drawing. This comparison algorithm, for example, may be used to verify a software program handling geometric objects consisted of trapezoids. In this paper, given k sets of trapezoids in which each set forms the regions of interest of each drawing, we present how to compare the k sets to see if all k sets represent the same geometric scene. When each input set has the same number n of trapezoids, the algorithm proposed has O(2$^{k-2}$ $n^2$(log n＋k)) time complexity. It is also shown that the algorithm suggested has the same time complexity O( $n^2$ log n) as the sweeping-based algorithm when the number k(<< n) of input sets is small. Furthermore, the proposed algorithm can be kn times faster than the sweeping-based algorithm when all the trapezoids in the k input sets are almost the same.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.1
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• pp.39-44
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• 2013

This study evaluated the effect of fluid flow on the power density in a horizontal-flow microbial fuel cell (MFC). The maximum power densities in four types of flow induced by different channel types in the anode chamber were investigated. The fluid flow at each channel was analyzed using tracer tests. Results of polarization curves showed that the maximum power densities of case 1, 2, 3 and 4 were 95.7, 129.1, 190.9 and 114.2 mW/m2, respectively. Case 3 with a set of guide walls where flow had an S type-like shape showed the highest power density. Based on the Morrill Dispersion Index (MDI) value of case 4, microbial activity would be enhanced since the reactor allows even distribution of substrate but the overflow occurrence would not guarantee stable performance. Therefore, case 3 could be an effective reactor type for MFC because of high electricity generation and stable performance.

• Archives of design research
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• v.20 no.1 s.69
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• pp.79-88
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• 2007

A company's plan to reform its products' image cannot obtain expected results unless a color plan is included in the reformation plan. A color plan is essential since color conveys to customers much information on function, shape, and material quality of the product. In other words, color is the essential dimension or criteria that customers use when evaluating the quality of goods. Despite the importance of a color plan, companies in Korea are still behind in researching and receiving 'color information' compared to those in more advanced countries. Recognizing the importance of products color, many international companies constantly make their efforts to predict trendy colors and preferred styles of customers before they develop products. It is suggested that domestic companies invest more in color infrastructure to be more successful in making products which can catch the customers' eyes and emotion. Different life styles by age, income level, and gender would be only a few of many factors to be investigated to build color plans for a product. In this study, it is attempted to see the color tendency of young generation by gender, and also to analyze empirically the influence of product's color on its image and customers' behavior. The results are analyzed with frequency analysis, cross tabulation analysis, T-test, one-way ANOVA using SPSS Win 12. The results of this study show that color preference, product image and product attitude are influenced by product's color, and color is an important factor for forming additional emotional value together with the product's original functional value. Judging from the findings, it is recommended that a company undertake careful research before developing a product to find out how customers respond differently to products in different colors especially when the product belongs to the product category where color is considered to be a determinant factor in terms of choosing a brand.

• Science of Emotion and Sensibility
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• v.14 no.2
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• pp.321-330
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• 2011

Images of smoky make up illustrations with different the brightness tones for typical Korean eyes (standard one, small single eyelid and tailed up style) were systematically analyzed using vision-based emotional descriptive language for students majoring makeup and professional group. We identified that various images could be expressed by changing smoky makeup tones on eyes types through analysis of the emotional descriptive language. The smoky make up image recognition of smoky make up illustrations was almost consistent between the students and the professional group, but there was the distinct difference of image perception by two groups for some smoky make up illustrations due to the generation gap as well as their make up expertise and techniques. We suggested the image positioning maps which expressed the emotional reaction felt according to eyes shapes and smoky make up tones. The positioning maps were to provide criteria for various images to be able to express by smoky make up.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.91-100
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• 2008

Numerical implementation with a Cartesian cut-cell method is conducted in this study. A Cartesian cut-cell method is an easy and efficient mesh generation methodology for complex geometries. In this method, a background Cartesian grid is employed for most of computational domain and a cut-cell grid is applied for the peculiar grids where the flow characteristics are changed such as solid boundary to enhance the accuracy, applicability and efficiency. Accurate representation of complex geometries can be obtained by using the cut-cell method. The cut-cell grids are constructed with irregular meshes which have various shape and size. Therefore, the finite volume method is applied to numerical discretization on a irregular domain. The HLLC approximate Riemann solver, a Godunov-type finite volume method, is employed to discretize the advection terms in the governing equations. The weighted average flux method applied on the Cartesian cut cell grid for stabilization of the numerical results. To validate the numerical model using the Cartesian cut-cell grids, the model is applied to the rectangular tank problem of which the exact solutions exist. As a comparison of numerical results with the analytical solutions, the numerical scheme well represents flow characteristics such as free surface elevation and velocities in x-and y-directions in a rectangular tank with the Cartesian and cut-cell grids.

• The KIPS Transactions:PartB
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• v.12B no.1 s.97
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• pp.47-56
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• 2005

A moving object has a various features that its spatial location, shape, and size are changed as time goes. In addition, the moving object has both temporal feature and spatial feature. It is one of the highly interested feature information in video data. In this paper, we propose an efficient content-based multimedia information retrieval system, so tailed ECoMOT which enables user to retrieve video data by using a trajectory information of moving objects in video data. The ECoMOT includes several novel techniques to achieve content-based retrieval using moving objects' trajectories : (1) Muitiple trajectory modeling technique to model the multiple trajectories composed of several moving objects; (2) Multiple similar trajectory retrieval technique to retrieve more similar trajectories by measuring similarity between a given two trajectories composed of several moving objects; (3) Superimposed signature-based trajectory indexing technique to effectively search corresponding trajectories from a large trajectory databases; (4) convenient trajectory extraction, query generation, and retrieval interface based on graphic user interface

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.476-481
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• 2016

Steam power generation is used to produce electricity through a generator that is connected to a steam turbine. As a result, the surface temperature of the deaerator is $70^{\circ}C$during the summer season, the surface temperature of the storage tank is $67^{\circ}C$, and the air temperature is $50^{\circ}C$. This environment is inappropriate for workers and instruments. Workers adjacent to the deaerator and storage tank in particular feel higher temperatures because of the radiative heat transfer effect. Therefore, we optimized the cooling conditions by computational analysis. Case 1 is the current shape of the power plant, Case 2 has additional insulation, and Case 3 has a radiation shield. Flow is caused by a temperature difference between the heat sources in the wall, and hot air is trapped in the right upper end. Based on the temperature contours and the maximum temperature of the surfaces, Case 2 was found to be the most efficient for reducing radiative heat transfer effects.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.391-397
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• 2016

Clostridium is a genus of Gram-positive, rod shape, spore-forming obligate anaerobe. Recently, Clostridium has been attracted as a host for bio-based chemical production, due to its diversity of substrate utilization and the production ability for metabolites which can be used as a building block for chemical production. Especially, butanol produced from Clostridium has been considered as an alternative fuel. As a transportation fuel, butanol has a higher energy density and lower hygroscopicity compared to ethanol, the first generation biofuel. Recently, metabolic engineering of Clostridium has been massively conducted for butanol production. In this study, the metabolic engineering strategy of Clostridium for butanol production has been reviewed with a brief perspective.