• Land and Housing Review
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• v.12 no.2
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• pp.99-108
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• 2021

With increasing interest in living in hanoks, there's a growing need for more quantitative data on the thermal comfort performance of modern hanoks. With that in mind, this research project studied a modern hanok located in Jamjeong-Haetsal Village in Hwasun, Jeollanam Province as a case study to evaluate the Predicted Mean Vote (PMV) of modernized hanoks. Based on environmental data collected at the hanok and computer simulation both Life-Cycle PMV (L.C.PMV) and Normal PMV (N.PMV) were calculated for the hanok. Study results showed that during the summer and winter seasons the PMV and heat index at major heat and major cold weather points significantly deviated from the comfort zone. The rate of change in PMV was also greater in the winter than in the summer. The study found that the modern hanok lacks proper thermal insulation for maintaining thermal comfort.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.199-212
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• 2018

This research concerns the prediction method for ground movement and wall member force due to determination structural stability check and failure check during deep excavation construction. First, research related with excavation influence parameters is conducted. Then, numerical analysis for various excavation conditions were conducted using Finite Element Method and Beam-column elasto-plasticity method. Excavation analysis database was then constructed. Using this database, development of ANN (artificial neural network) was performed for each ground movements and using structural member forces. By comparing the numerical analysis results with ANN's prediction, it is validated that development of ANN can be used efficient for prediction of ground movement and structural member forces in deep excavation site.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1393-1406
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• 2018

In this study, three parameters (Pressure ($X_1$), Airflow rate ($X_2$), Operation time ($X_3$)) were experimentally designed and the predicted model and optimal conditions were established by using the terminal rise velocity of the microbubbles as the response value. The polynomial regression analysis showed that the optimum value for the terminal rise velocity at the Pressure ($X_1$) of 4.5 bar, Airflow rate ($X_2$) of 3.3 L/min and Operation time ($X_3$) of 2.2 min was 5.14 cm/min ($85.7{\mu}m/sec$). Also, the highest microbubble diameter size distribution in the range of 2 to $5{\mu}m$ and 25 to $50{\mu}m$ was confirmed by using a laser particle counting apparatus.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.69-74
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• 2018

In this paper, We investigated the effects of mesh structure variations of meshed ground on MCAA(Microstrip Comb Array Antenna). First, we designed MCAA in 24GHz ISM band and we investigated the variations of the gain and the SLL(Side Lobe Level) of the MCAA as we varied the mesh structure of the meshed ground. We varied two variables, mesh size and unfilled rato, which is defined as no metal area ratio in mesh for the investigation. We investigated two types of MCAA. Those are flat MCAA composed of flat radiator and tapered MCAA composed of tapered radiator. Both the antenna gains of flat MCAA and tapered MCAA are decreased as the unfilled rato increased. However, increase of mesh size made more dramatic decrease in antenna gain than increase of unfilled rato. The antenna SLL showed similar trend. But tapered MCAA affected more severely by variation of mesh size than flat MCAA.

• The Journal of Korean Institute of Information Technology
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• v.16 no.11
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• pp.43-49
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• 2018

Computer simulation was performed using the SIMION program to develop an electron gun for MCP cleaning. The target, MCP, is located 180mm from the source of the electron gun, and the diameter of the MCP is approximately 20mm. Therefore, we tried to find the condition that the beam diameter of electrons reaching the MCP is to be 20mm using four variables such as E, ${\phi}$, d1, d2, where the E is the energy of the electron reaching the MCP, the ${\phi}$ is the diameter of the extractor, and the d1 and the d2 are the distance from the electron source to the end of the extractor tube, and to the wall of chamber, respectively. As a result of simulation, we figuried out that the E and the d2 have little effect on the beam diameter. On the other hand, we also found that the beam diameters were very sensitive to the d1 and varied relatively large with respect to the ${\phi}$, and the d1 was the secondary order function of the ${\phi}$. Therefore we found that this function will allow us to design electron guns that are suitable for the purposes of this study.

• Journal of the Korean GEO-environmental Society
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• v.19 no.12
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• pp.33-39
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• 2018

In this study, important characteristics were identified for the Geosynthetic-soil interface using overburden pressure and saltwater and fresh water to evaluate silt shear behavior of the Geosynthetic-soil interface. In addition, waste landfill can secure spaces for waste disposal in the sea and this spaces can be used for additional facilities which will be necessary in the future. Analysis of behavior characteristics on interface of Geosynthetic-soil shows that, if analyzed using standard consolidometers, the consolidation stress of fresh water increased significantly more than saltwater. When analyzed using cyclic shear apparatus, saltwater and freshwater in both conditions, the displacement value increases as the wire gauges become closer to the lower module, and the shear fracture tends to occur radically under saltwater conditions than fresh water. Therefore, seawater, fresh water that act on the interface of geosynthetic-soil, and installation of facility using geosynthetic should be considered as important parameters that are essential for the dynamic design factor of the water controlling facility.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.914-920
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• 2018

The intrinsic kinetic parameters of steam-methane reforming reactions over commercial nickel-based catalyst were determined. The reaction rate equations were derived from the reaction mechanism-based Langmuir-Hinshelwood chemisorption theory. As the experimental variables for the kinetic study, the reaction temperature ranged from 630 to $750^{\circ}C$ and the steam-to-carbon ratio also varied from 2.7 to 3.5. Based on the experimental data, the efficient optimization algorithm was used to determine the intrinsic kinetic parameters due to the high-dimensional objective function. It is confirmed that the parameter estimation results showed good agreement with the experimental values. Thus, this proposed mathematical reaction model can be used as the basic information to design a catalytic reactor and to optimize operating conditions.

• Journal of Aerospace System Engineering
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• v.13 no.1
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• pp.18-28
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• 2019

High speed vehicles are subjected to high thermal loadings due to aerodynamic heating during ascent and reentry. Since a thermal protection system panel is mechanically constrained, it may cause thermal buckling under excessive thermal loadings. The thermal buckling could disturb the field of flow and make aerodynamic characteristics unstable. It is thus necessary to design the thermal protection system panel to prevent thermal buckling. This study defines the analytical model of temperature distribution using the finite difference method for the thermal protection system panel with large temperature differences inside and outside. This paper proposes the approximate model of the thermal buckling characteristics for the thermal protection system panel through the use of the Ritz method. The validity of the present method was verified by comparing the results of the finite element analysis. Furthermore, this research performs the parametric analysis of the thermal buckling characteristics for the thermal protection system panel by using the approximate model.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.263-271
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• 2018

The aim of this study was to investigate whether there is the relationship between husband support and depression mediated to connubial bliss in Korean married women. A total of 2,120 married women were selected from the database of the Fourth Korea Longitudinal Survey of Women and Families (KLoWF) in 2011-2012. By the structure equation model, among of the husband support, the husband awareness was regarded as the dominant factor related to depression in Korean married women. Then comes couple activity, visiting of parents and division of household labor in that order. This study suggests that husband support significantly associated with connubial bliss and depression in Korean married women. The above findings will help design policy plans to reduce the depression of married women in the nation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.336-341
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• 2018

The prestressing force introduced to the tendon in pretensioned concrete members is transferred by direct bond between tendon and concrete, which requires a proper estimation of stress transfer length. The use of pretensiond and/or precast members with UHPC (Ultra High Performance Concrete) may give many advantages in quality control. This paper presents an experiment to estimate the stress transfer length of UHPC for various compressive strength levels of UHPC, cover depths, diameters of tendons and tensioning forces. According to the result of this experiment, the stress transfer length of UHPC member is much reduced comparing that of normal strength concrete. The reduction in stress transfer length of UHPC may come from the high bond strength capacity of UHPC. The transfer lengths obtained from this experiment are compared to those in current design code and a new formula is proposed.