• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.3
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• pp.209-215
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• 2007

To improve the accuracy of frost warning system for pear orchard in a complex terrain in Naju area, the daily minimum temperature forecasted by Korea Meteorological Administration (KMA) was interpolated using a regional climate model based on topoclimatic estimation and optimum scale interpolation from 2004 to 2005. Based on the validation experiments done for three pear orchards in the spring of 2004, the results showed a good agreement between the observed and predicted values, resulting in improved predictability compared to the forecast from Korea Meteorological Administration. The differences between the observed and the predicted temperatures were $-2.1{\sim}2.7^{\circ}C$ (on average $-0.4^{\circ}C$) in the valley, $-1.6{\sim}2.7^{\circ}C$ (on average $-0.4^{\circ}C$) in the riverside and $-1.1{\sim}3.5^{\circ}C$ (on average $0.6^{\circ}C$) in the hills. Notably, the errors have been reduced significantly for the valley and riverside areas that are more affected by the cold air drainage and more susceptible to frost damage than hills.

• Archives of design research
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• v.19 no.5 s.67
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• pp.351-362
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• 2006

Currently, finding one's way in the underground spaces associated with subway stations in large cities is becoming a serious problem, and an environment that facilitates wayfinding is becoming more important. This study investigated interior treatments that function as visual cues in the subway stations of Seoul, Tokyo, and Taipei in order to develop design guidelines that would improve the place-cognition environment. A theoretical study has shown that there are three categories of visual cue for place cognition: marked trails, regional differentiation, and landmarks. The case study showed that marked trails involve treatments like vertical markers, confrontational positioning, and subway color codes. Regional differentiation involves patterns on the floors and walls, and accent colors on the walls and columns. Landmarks include treatments such as super graphics, symbolic features, artistic decoration and special lights. In the cases of Seoul, marked trails and regional differentiation were predominant. In addition, the Olympic symbol 'Hodori' and the ancient Korean character "Hunminjungeum" were used as landmarks. In the cases of Tokyo, regional differentiation predominated over marked trails because of the complexity of the spatial structure and subway line connection system. In the cases of Taipei, simple, unified images predominated, and there was minimal dependence on marked trails and landmarks. The need for regional differentiation was weak, because the stations studied have open structures that guarantee an open field of view. The results of this research could be used as design guidelines, after further experimental verification, that would help to improve the public environment in terms of wayfinding.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.237-242
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• 2015

With the rapid development of modern society, subway has become one of the most typical urban transport systems. Since fire accident occurred at Daegu subway in 2003, importance of life safety and disaster prevention have been widely recognized and many studies have been carried out. As a result of these studies, fire-retardant and non-combustible interior material and platform screen door with passenger guide indication device have been developed, but studies on a subway evacuation criteria have been in a stalemate. Therefore, this study is intended to improve the subway evacuation standard. It is very difficult to take into account whole subway system, so a typological approach to a ticket was carried out referring to previous studies focused on a subway platform. this paper selected the most common subway platforms and estimated evacuation time among 10 platforms from previous studies and 8 from this study. As a result, evacuation time exceeded 6 minutes which is the guideline of existing standard. Therefore, it is necessary to update the standard for evacuation time and add supplementary conditions which can help establishing the measures for safety facilities and prevention measures.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.453-467
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• 2018

The excavation performance and the cutting tool wear prediction of shield TBM are very important issues for design and construction in TBM tunneling. For hard-rock TBMs, CSM and NTNU model have been widely used for prediction of disc cutter wear and penetration rate. But in case of soft-ground TBMs, the wear evaluation and the excavation performance have not been studied in details due to the complexity of the ground behavior and therefore few testing methods have been proposed. In this study, a new soil abrasion and penetration tester (SAPT) that simulates EPB TBM excavation process is introduced which overcomes the drawbacks of the previously developed soil abrasivity testers. Parametric tests for penetration rate, foam mixing ratio, foam concentration were conducted to evaluate influential parameters affecting TBM excavation and also ripper wear was measured in laboratory. The results of artificial soil specimen composed of 70% illite and 30% silica sand showed TBM additives such as foam play a key role in terms of excavation and tool wear.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.3
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• pp.625-639
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• 2018

This study is about the reinforcing type of reinforcement method which is reinforced in tunnel portal of tunnel with bad ground condition. Generally, it is known that the horizontal reinforcement method is more effective than the conventional reinforcement method. However, as a limitation of the tunnel construction technology, it is being constructed by the superposition reinforcement method. In recent years, high-strength large-diameter steel pipes and horizontally oriented longitudes (L = 30.0~50.0 m) construction technology have been developed. Therefore, it is required to study reinforcement method of tunnel portal reinforcement method. Therefore, 3-D numerical analysis (Midas GTS NX 3D) was performed by setting the reinforcement method (No reinforcement type, overlap reinforcement type and horizontal reinforcement type) and ground condition as parameters. As a result, it was considered that the reinforcement effect was the largest as the horizontal reinforcement type of the reinforcement method was the smallest in the displacement and the support material stress. Based on the results of the numerical analysis, horizontal steel pipe grouting was applied to the actual tunnel site. The displacement of the tunnel portal and the stress of the support material occurred within the allowable values and were considered to ensure sufficient stability.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.2
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• pp.151-163
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• 2006

Although various methods for effective modeling of pre-reinforced zones have been suggested for numerical analysis of large section tunnels, tunnel designers refer to empirical cases and literature reviews rather than engineering methods because ones who use commercial programs are unfamiliar with a macro-scale approach in general. Therefore, this paper suggests a simple micro-scale approach combined with the macro-scale approach to determine equivalent design parameters for effective numerical modeling of pre-reinforced zones in tunnel. This new approach is to determine the equivalent stiffness of pre-reinforced zones with combination of ground, bulb, and steel in series or/and parallel. For verification, 3-D numerical results from the suggested approach are compared with those of a realistic model. The comparison suggests that two cases make best approximation to a realistic solution: One is related to the series-parallel stiffness system (hereafter SPSS) in which bulb and steel are coupled in parallel and then connected to the ground in series, and the other is the series stiffness system (hereafter SSS) in which only bulb and steel are coupled in series. The SPSS is recommended for stiffness calculation of pre-reinforced zones because the SSS is inconvenient and time-consuming. The SPSS provides slightly bigger vertical displacement at tunnel crown in weathered rock than other cases and give almost identical results to a realistic model for horizontal displacement at tunnel spring line and ground surface settlement. Displacement trends on weathered rock and weathered soil are similar. The SPSS which is suggested in this paper represents the behavior mechanism of pre-reinforced area effectively.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.1
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• pp.39-53
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• 2018

Generally, the total ventilation resistance coefficient in a tunnel consists of inlet/outlet loss coefficient, wall friction coefficient, and other loss coefficient caused by sudden expansion and contraction of cross-section, etc. For the tunnel before opening, when the running ventilation fan is stopped, the wind speed in the tunnel is reduced by the total ventilation resistance drag. The velocity decay method is comparatively stable and easy to estimate the wall friction coefficient in the pre-opening tunnel. However, the existing study reported that when the converging wind speed is a negative value after the ventilation fan stops, it is difficult to estimate the wall friction coefficient according to the velocity decay method. On the other hand, for the operating tunnel in which the piston effect acts, a more complex process is performed; however, a reasonable wall friction coefficient can be estimated. This paper aims at suggesting a method to minimize the measurement variables of the piston effect and reviewing a method that can be applied to the operating tunnel. Also, in this study, a new method has been developed, which enables to calculate an variation of the piston effect if the piston effect is constant with a sudden change of external natural wind occurring while the wind speed in the tunnel decreases after the ventilation fan stops, and a programming logic has been also developed, which enables dynamic simulation analysis in order to estimate the wall friction coefficient in a tunnel.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.5
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• pp.57-67
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• 2013

The studies of Korean traditional gardens have been a lot of diachronic approaches through ancient documents and on-site investigation. Previous research has focused on the characteristics that are inherent symbolism of the traditional landscape space, such as site characteristics. There are many studies for inner gardens, outer gardens and other influential ranges of gardens of the location characteristics. However, studies on the scale of external gardens were not satisfactory from a quantitative perspective. Unlike private life sphere, quantitative analysis was conducted on the role of a sphere of public community life for outer gardens. Visibility analysis was performed through the existing literature and GIS programs to estimate the magnitude of the outer garden. When it was compared with Min G. H.(1982) research, it is almost the same if it is estimated to focus on Buyoung -bong(芙蓉峯) and Ip-am(立巖). Also, as a result of the fractal structure for a variety of symbols in the garden, fractal dimension in landscape elements is relatively concentrated, unlike in other areas. Thus, the external scale can be a means of cultural property protection out of the crucial perspective for the inner garden. There has been consideration of the cooperation with the visual complexity using the concept of fractal structure as one of the elements of landscape analysis.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.67-73
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• 2006

Purpose: The number of patients receiving radiotherapy has increased every year and will keep increasing in the future. Therefore, the technique of radiotherapy is developing from day to day, as a result of it, the quantities of image and data used for radiotherapy are also considerably increasing. Therefore, there have been many difficulties in storing, keeping and managing them. Then, we developed and applied this system for improving complicated work process as well as solving these problems with the collaboration Medical Information Team. Materials and Methods: We exported its image at R & V (Record and Verify: Varis vision, Varian, USA) system and planning system after giving some code to be able to access from management system(RO) for department of radiation oncology to PACS. And, we programmed their information by using necessary information among many information included in DICOM head. Results: All images and data generated by our working environment (Simulation CT, L-gram image and internal body structure, DRR, does distribution )were realized at PACS and it became to be possible for clear image to be printed from any computer in department of radiation oncology. Conclusion: It was inevitable to use film during radiotherapy for patients in the past, however, due to the development of this system, film-less system became to be possible. Therefore, the darkroom space and its management cost in relation to the development process disappeared and it became to be unnecessary for spending tangible and intangible financial expense including human resources, time needed for finding film storing space and film and purchasing separate storing equipment for storing images. Finally, we think this system would be very helpful to handle ail complicated processes for radiotherapy and increasing efficiency of overall working conditions.

• The KIPS Transactions:PartB
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• v.9B no.2
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• pp.139-146
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• 2002

The robot soccer simulation game is a dynamic multi-agent environment. In this paper we suggest a new reinforcement learning approach to each agent's dynamic positioning in such dynamic environment. Reinforcement learning is the machine learning in which an agent learns from indirect, delayed reward an optimal policy to choose sequences of actions that produce the greatest cumulative reward. Therefore the reinforcement learning is different from supervised learning in the sense that there is no presentation of input-output pairs as training examples. Furthermore, model-free reinforcement learning algorithms like Q-learning do not require defining or learning any models of the surrounding environment. Nevertheless these algorithms can learn the optimal policy if the agent can visit every state-action pair infinitely. However, the biggest problem of monolithic reinforcement learning is that its straightforward applications do not successfully scale up to more complex environments due to the intractable large space of states. In order to address this problem, we suggest Adaptive Mediation-based Modular Q-Learning (AMMQL) as an improvement of the existing Modular Q-Learning (MQL). While simple modular Q-learning combines the results from each learning module in a fixed way, AMMQL combines them in a more flexible way by assigning different weight to each module according to its contribution to rewards. Therefore in addition to resolving the problem of large state space effectively, AMMQL can show higher adaptability to environmental changes than pure MQL. In this paper we use the AMMQL algorithn as a learning method for dynamic positioning of the robot soccer agent, and implement a robot soccer agent system called Cogitoniks.