• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.4
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• pp.525-540
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• 1997

The effect of mold rotation on the transport process and resultant macrosegregation pattern during solidification of an Al-Cu alloy contained in a vertical axisymmetric annular mold cooled from the inner wall is numerically investigated. The mold initially at rest starts to rotate at a prescribed angular velocity simultaneously with the beginning of cooling. Computed results for a representative case show that the mold rotation essentially suppresses the development of both thermal and solutal convections in the melt, creating distinct characteristics such as the liquidus front, flow pattern and temperature distribution from those for the stationary mold. Thermal convection which develops at the early stages of cooling is soon extinguished by the rotating flow induced during spin-up, and thus does not effectively remove the initial superheat from the melt. On the other hand, solutal convection, though it weakens considerably and is confined within the mushy zone, still predominates over the solute redistribution process. With increasing the angular velocity, the solute transport in the axial direction is enhanced, whereas that in the radial direction is reduced. The final macrosegregation formed in the mold rotating at moderate angular velocities appears to be favorable in comparison with the stationary casting, in that not only relatively homogenized composition is achieved, but also a severely positive-segregated channel is restrained.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.12
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• pp.1692-1701
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• 2001

This study describes the combustion characteristics under various condition of air excess ratio and ignition timing in a 2-valve SI optically accessible engine with swirl control valve(SCV). It adapted three different types of SCV(open ratio 72.5%, 78%, 59%) to strengthen a swirl flow. Pressure data were acquired using pressure sensor to investigate the effect of swirl flow on combustion, and from these pressure data, IMEP(indicated mean effective pressure) and MFB(mass fraction burnt) were calculated to explain burn rate and flame speed. From acquired flame images, we inspected the flame propagation direction, flame area, and flame centroid. Flame propagation direction showed different tendency between with/without SCV, and flame area with SCV was faster and larger than that of conventional engine. Finally, the representative flame images at each crank angle were acquired by PDF method to verify flame growth process. It is found that strengthened swirl flow is more beneficial for faster and stable combustion.

• Transactions of Materials Processing
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• v.21 no.8
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• pp.479-484
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• 2012

The objective of this study is to compensate the elastic recovery in the flexible forming process using the predictive models. The target shape was limited to two-dimensional shape having only one curvature radius in the longitudinal-direction. In order to predict the shape error the regression and neural network models were established based on the finite element (FE) simulations. A series of simulations were conducted considering input variables such as the elastic pad thickness, the thickness of plate, and the objective curvature radius. Then, at sampling points in the longitudinal-direction, the shape errors between formed and objective shapes could be calculated from the FE simulations as an output variable. These shape errors were expressed to a representative error value by the root mean square error (RMSE). To obtain the correct objective shape the die shape was adjusted by the closed-loop using the neural network model since the neural network model shows a higher capability of estimating the shape error than the regression model. Finally the experimental result shows that the formed shape almost agreed with the objective shape.

• Publications of The Korean Astronomical Society
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• v.25 no.4
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• pp.119-128
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• 2010

Gaecheonjeol is the National Foundation day of Korea when people hold a harvest ceremony. Nowadays, two representative harvest ceremonies of Korea are performed at Mt. Mari (摩利山) and Mt. Taebaek (太白山) on Gaecheonjeol (October 3rd). We study 28 flags with constellations appearing in the ceremony of Mt. Taebaek. These flags are lying in the outer of the circular stone wall during the ceremony. They represent an oriental heavenly star chart. We examine the shape, the connecting-pattern, the name, and the number of constellations drawn in the flags, and find several errors, such as, a wrong position, a typo of name, an irregular size, an omission, and so forth. Traditionally, the 28 oriental constellations are usually divided into four groups and each group has its own colour for each direction: Blue (E), Black (N), White (W), and Red (S). For the constellation flags in Mt. Taebaek, the colour of the flags is painted based on geographical directions, but the constellations are arranged followed by the direction of the celestial sphere. Thus, constellations in the northern and southern parts are counterchanged. Finally, we suggest some possible criteria for constellation map of the flags in this paper. CheonSangYeolChaBunYaJiDo (天象列次分野之圖) and CheonMunRyuCho (天文類抄) can be essential references for correcting constellations drawn in the flags of Mt. Taebaek.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.141-151
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• 2022

Taking the different inheritance methods of representative successors, dance education at university, and convergent media as a research object, this research discusses the changes in the development direction of inheritance of traditional dances of China's intangible cultural heritage, analyzes the inheritance and development path of traditional dances. The purpose of this research is to realize the inheritance of dance culture and strengthen the influence of Chinese traditional dance culture in the world.

• Journal of Urban Science
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• v.11 no.1
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• pp.37-47
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• 2022

Even if Korea has established various legal guidelines as well as plans for the purpose of systematic management of urban citycapes, various problems have been pointed out, such as a decrease in operational efficiency because the legal framework is not clearly defined and the guidelines do not fully reflect regional characteristics. In the midst of this, Singapore is being mentioned as a representative example of enhancing international competitiveness by forming an outstanding urban cityscape through successful urban planning and operating system. Therefore, this study aims to suggest a direction for the improvement of Korea's urban planning and design guidelines by investigating and analyzing the characteristics of Singapore's urban planning system and design guidelines. As a result of the research and analysis, it was concluded that Singapore's urban planning system was based on the unified planning and management system. In particular, the Singapore Urban Design Guidelines provide differentiated guidelines to maintain and strengthen regional characteristics based on linkage with higher-level plans as detailed practical guidelines, and were operated as flexible guidelines reflecting the changes of the times and the needs of members of society. It also provides a direction for the improvement of the Korean urban design system, such as to increase the executionablity of the plan and the efficiency of operation by utilizing various guidance and support policies, rational and simplified deliberation procedures, and allow a platform that enhances the accessibility and convenience of related information.

• The Korean Journal of Community Living Science
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• v.18 no.4
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• pp.655-670
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• 2007

The purpose of this study was to develop a brand naming strategy for rural specialty products of Muju. This study was to apply brand development research to the field. The selected investigation subject, a local farming operation producing a specialty product, was chosen from a New Enterprise Support Project of Farm Women ('06). The selected subject was a farming operation producing bokbunja drink in Muju. The data was derived from 137 female consumers. The major results of this study were as follows. First, the process of brand development strategy was advanced by six steps: Step 1, environment analysis; Step 2, brand case study; Step 3, SWOT analysis (Strength Weakness, Opportunity, Threat factor analysis); Step 4, direction design for brand naming development (Targeting, Brand focus concept extraction); Step 5, brand logo and symbol production; and Step6, Evaluation. Second, to extract brand naming development direction, key concepts in association with natural connection, area features, representative resources, and natural friendship were investigated. Namely, the health function concept was selected on the basis of a consumer recognition investigation where results appeared most highly favorable. Also, it was decided that the direction of brand naming should emphasize a green image and the location name of Muju. Finally, the brand name was decided to be "Saenggichan" bokbunja liquid and the slogan went with "guchondon-native thorn bokbunja from jar maturing."

• Economic and Environmental Geology
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• v.32 no.2
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• pp.189-201
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• 1999

Paleomagnetic and rock magnetic investigations have been carried out for the Cretaceous Hanyang Group, exposed in the Yongyang Sub-Basins within the Kyeongsang Basin, eastern South Korea. A total of 452 oriented core samples was drilled from 31 sits for the study. The in-situ site mean direction is more dispersed than the mean direction after bedding correction, indicating that the fold test is positive at 95% confidence level. In addition, the stepwise unfolding of the characteristic remanent magfold test is positive at 95% confidence level. In addition, the stepwise unfolding of the characteristic remanent magnetization reveals that a maximum value of k is observed at 90% unfolding. Furthermore, the rock magnetic investigations and electron microscope observations of the representative samples show that the main magnetic carrier of the Hayang Group is the detrital specular hematite of single and pseudo-single domain sizes with negligible contribution of pigmentary hematite grains. These results collectively imply that the ChRM direction is the primary component acquired at the time of the formation of the strata. Provided the primary nature of the ChRM, a magnetostratigraphic correlation between polarities of the studied formation and the Geomagnetic Time Scale indicates that the Hayang Group in the Yongyang Sub-Basin can be correlated to the Cretaceous Long Normal superchron. The paleomagnetic pole position from this study is significantly different from those of the Hayang group in the Euiseong the Milyang sub-Basins. Rather the paleomagnetic pole position of the Hayang Group of the study area is closer to that of the Quaternary period or present time of the Korean Peninsula. It is hypothesized that the study area might be rotated about 25$^{\circ}$ aticlockwise with respect to the Euiseong and Milyang Sub-Basins after the formation of the strata and aquisition of the ChRM, although there is not enough geologic evidence supporting the rotation hypothesis.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.5
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• pp.395-401
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• 2018

Recently, most of mobile devices are equipped with GNSS (Global Navigation Satellite System). When the GNSS signal is available, it is easy to obtain position information. However, GNSS is not suitable solution for indoor localization, since the signals are normally not reachable inside buildings. A wide varieties of technology have been developed as a solution for indoor localization such as Wi-Fi, beacons, and inertial sensor. With the increased sensor combinations in mobile devices, mobile devices also became feasible to provide a solution, which based on PDR (Pedestrian Dead Reckoning) method. In this study, we utilized the combination of three sensors equipped in mobile devices including accelerometer, digital compass, and gyroscope and applied three representative PDR methods. The proposed methods are done in three stages; step detection, step length estimation, and heading determination and the final indoor localization result was evaluated with terrestrial LiDAR (Light Detection And Ranging) data obtained in the same test site. By using terrestrial LiDAR data as reference ground truth for PDR in two differently designed experiments, the inaccuracy of PDR methods that could not be found by existing evaluation method could be revealed. The firstexperiment included extreme direction change and combined with similar pace size. Second experiment included smooth direction change and irregular step length. In using existing evaluation method which only checks traveled distance, The results of two experiments showed the mean percentage error of traveled distance estimation resulted from three different algorithms ranging from 0.028 % to 2.825% in the first experiment and 0.035% to 2.282% in second experiment, which makes it to be seen accurately estimated. However, by using the evaluation method utilizing terrestrial LiDAR data, the performance of PDR methods emerged to be inaccurate. In the firstexperiment, the RMSEs (Root Mean Square Errors) of x direction and y direction were 0.48 m and 0.41 m with combination of the best available algorithm. However, the RMSEs of x direction and y direction were 1.29 m and 3.13 m in the second experiment. The new evaluation result reveals that the PDR methods were not effective enough to find out exact pedestrian position information opposed to the result from existing evaluation method.

• Journal of the Ergonomics Society of Korea
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• v.36 no.4
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• pp.343-353
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• 2017

Objective: This study aims to evaluate the efficiency of two representative subway map design types, namely a diagram type and a geographical type using physiological metrics, performance metrics, and self-reported metrics, which are representative usability metrics. Background: Subway maps need to be designed in order for users to quickly search and recognize subway line information. Although most cities' subway maps currently use the diagram type designed by Henry Beck, New York City's subway map has recently been changed to the subway map type combined with the geographical type designed by Michael Hertz. However, not many studies on its efficiency are found, and the studies that are available mainly depend on questionnaire surveys or take on a subjective behavioral study type based on experts' experiences. In this regard, evaluation through a more objective method is needed. Method: This study employed usability metrics as a method to evaluate the efficiency of information search targeting the diagram type and geographical type subway maps used mostly as subway maps. To this end, physiological metrics obtained through eye tracking, task completion time, representative metric of task performance, and subjective evaluation metrics were used for the suitability evaluation of subway map designs. Results: In the result of gaze movement distance analysis, no significant difference was shown in the two design types in terms of a process finding a departure station from the starting point and a process finding a transfer station between the departure station and arrival station (destination). However, the gaze movement distance in the process finding the arrival station at the departure station was significantly shorter in the geographical type, rather than in the diagram type. The analysis of task completion time showed a result similar to the gaze movement distance analysis result. Task completion time was significantly shorter in the geographical type, rather than in the diagram type, which is in the process finding the arrival station at the departure station. In other information search processes, no significant difference was shown. As a result of subjective evaluation metrics analysis, no significant difference was revealed in the two design types. Conclusion: An analysis on the two representative subway map design types was carried out via the adoption of usability metrics. As a result, although no significant difference was shown in some information search processes, it was revealed that information search was easier in the geographical type overall. Also, it was found that usability metrics can be effectively used to evaluate the design types of subway maps. Application: The study results can be used to set design direction to offer ease in information search on subway lines. The study also can be used as a method to evaluate a subway map's design type.