• Journal of the Korean Geotechnical Society
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• v.29 no.6
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• pp.5-17
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• 2013

Slug tests can be adopted to estimate hydraulic conductivity of the slurry trench wall backfill for its abilities to reflect the in-situ performance of the construction. A comprehensive three-dimensional numerical model is developed to simulate the slug test in a slurry trench wall considering the presence of bentonite cake on the interface boundaries between the wall and the surrounding soil formation. Influential factors such as wall width (i.e., proximity of wall boundary), well deviation, vertical position of well intake section, compressibility of wall backfill, etc. are taken into account in the model. A series of simulation results are examined to evaluate the bentonite cake effect in analyzing practical slug test results in the slurry trench wall. The results show that the modified line-fitting method can be used without any correction factor for the slug test in the slurry trench wall with the presence of bentonite cake. A case study is reanalyzed with the assumption of existing bentonite cake. The results are compared with the previously reported results by the approaches assuming no bentonite cake (constant-head boundary) or upper-bound solution (no-flux boundary). The case study demonstrates the bentonite cake effect and the validity of the modified line-fitting method in the estimation of the hydraulic conductivity of the slurry wall backfill.

• Asian Journal of Atmospheric Environment
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• v.9 no.2
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• pp.165-172
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• 2015

Under a very tough situation that there has been increasing concern to the air quality in underground subway spaces, this study set sights on the thorough estimation of the chemical properties and source apportionment of particulate matter (PM) collected on an underground subway platform by a cooperative approach of semi-bulk and single particle analyses. The size-resolved PMs were intensively collected on the platform of Miasageori station on the Seoul Subway Line-4, and then, they were semibulkily analyzed by a PIXE and the TOR$^{(R)}$ method, and individually analyzed by a SEM-EDX. Overwhelmingly enriched iron was a notable feature of elemental concentration of $PM_{2.5}$. Source classification of iron in $PM_{10-2.5}$ and $PM_{2.5}$ performed along with their elemental concentrations, indicates that the railway originated iron accounts for 95.71% and 66.39% of total iron in $PM_{10-2.5}$ and $PM_{2.5}$, respectively. Via a stoichiometric categorization, $Fe_2O_3$, $CaAl_2Si_2O_8$, $Al_2O_3$, and $CaCO_3$ show more than 85% abundance ratio in individual coarse particles. The result of theoretical estimation of the subway derived organic carbon ($OC_{Subway}$) suggests that $OC_{Subway}$ in $PM_1$ and $PM_{2.5-1}$ account for 75.86% and 51.88% of total organic carbon, respectively.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.47-60
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• 2010

This study is focused on the analysis of tunnel behavior to estimate the stability on tunnel design. An estimation method was proposed as a hybrid consideration, which contains the displacement analysis by 3D numerical simulation, the maximum displacement obtained after field measurement, and an assessment of tunnel stability using a deformation analysis proposed by Sakurai(1988, 1997). The points of case study by Sakurai(1988, 1997) were replotted considering his analysis. From the new analysis of the tunnel case study, the trend line for analyzed points is analogized, which curve is divided into stable, unstable and failure zone. To evaluate the estimation method, a special shape of railway tunnel was selected, which are the Inchon international airport rail way connected to subway line 9 in Gimpo, Korea. The point s of upper and below track on the Inchon international airport rail way were satisfied to the stability of tunnel after reinforcing. Also the points shows the higher apparent Young's modulus, which resulted from improvement on shear strength by the micro silica grouting and the supporting of umbrella method. Therefore, if new analysis used, proper tunnel reinforcing method could be selected according to tunnel strain and geological property.

• Journal of the East Asian Society of Dietary Life
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• v.2 no.1
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• pp.57-68
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• 1992

In order to obtain the information on the status of using university cafeteria and students' preferences, the survey was conducted through questionaires to 434 students(male:195, female : 239) of 8 universities - 2 universities employed dietitian and 6 universities which didn't employ dietitian -through all the area of Incheon from 19th November 1990 to 14th December, 1990. The results obtained were as follows. 1) For keeping temperature of meals until service to students Refrigerator or warming cabinet or putting meals on low flames were used, and the amount for one person was almost decided by rough estimation by experience. All the foods remained were discarded. Also most of the cooking manager's age were from 50 to 59 and almost cooking managers graduated middle school. The fuel to cook was gas or kerosene. Method to disinfect tableware was boiling. 2) In case of the frequency of using university cafeteria, male students used cafeteria more often than female students, and regardless of sex students made use of cafeteria for lunch more than for breakfast and supper. Students also used university cafeteria not employing dietitian more than cafeteria employing dietitian. Disregarding of male, female, cafeteria employing cafeteria not employing dietitian, all students pointed out that main reason for using cafeteria were 'low price' and 'no other place to eat' And minor reasons were ' good taste' and 'meal quality'. On the contrary, the case of not using cafeteria were 'waiting in line' to male students, 'poor taste' to female students, 'waiting in line' and 'no varieties' on the cafeteria which employed dietitian, 'poor taste' and 'poor hygienes' on the cafeteria which didn't employ dietitian. 3) Considering of the preferences of menu, both male and female students liked "Bibim Bab" And male students prefered meals which contained broth both but female students prefered a light meals. 4) the difference of preferences showed that female student's preferences were high at all foods, and the preferences of fruits were high for both students. In detail, male students liked port, liver and small intestine of cattle, oyster and beans boiled in soysauce. But female students likde milk, yogurt and cucumber.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.4
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• pp.103-111
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• 2018

The Soswaewon Garden, which was constructed by Yang San-Bo around 1520, is a private traditional garden in Korea. Soswaewon Garden has long been and still is the focus of continuous research. However, relatively few studies have been conducted on the restoration of buildings that were lost in the past. The Goam-Jeongsa and Boohwondang buildings, which were lost in 1597 during the Japanese invasion, were restored in 1614 and depicted in a picture of Soswaewon Garden in 1755. However, they eventually disappeared and no longer exist in the present. Therefore, the restoration of these two buildings is considered an urgent task. This research aims to search for the original location of these buildings and estimate their size and shape in terms of physical space. Several years ago, an estimation of the building site was carried out, providing a stepping stone on this matter. This can be studied through "Soswaewon's 48 quatrains with five Chinese characters in each line," "Soswaewon-sasil," and "Soswaewon's drawing." Some parts of the shape of Soswaewon also appear in the "Yuseoseokrok," which is helpful. Thus, in this research, information on the Goam-Jeongsa and Boowondang buildings appearing in research results and literature to date are collectively analyzed. The location and architectural features of both buildings are identified by focusing on excavations. Also, for the purpose of restoration planning, base data on the location, size, and shape of both buildings are presented. In line with this process, a valid restoration plan is presented by analyzing the abovementioned historical research materials and comparing empirical data, such as excavation results.

• Economic and Environmental Geology
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• v.53 no.3
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• pp.245-258
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• 2020

In this study, a data-driven response surface method using the results acquired from the numerical simulation is developed to evaluate the potential storage capacity of groundwater due to the construction of a groundwater dam. The hydraulic conductivities of alluvium and basement rock, depth and slope of the channel are considered as the natural conditions of the location for groundwater dam construction. In particular, the probability models of the hydraulic conductivities and the various types of geometry of the channel are considered to ensure the reliability of the numerical simulation and the generality of the developed estimation model. As the results of multiple simulations, it can be seen that the hydraulic conductivity of basement rock and the depth of the channel greatly influence to the groundwater storage capacity. In contrast, the slope of the channel along the groundwater flow direction shows a relatively lower impact on the storage capacity. Based on the considered natural conditions and the corresponding numerical simulation results, the storage capacity estimation model is developed applying an artificial neural network as the nonlinear regression model for training. The developed estimation model shows a high correlation coefficient (>0.9) between the simulated and the estimated storage amount. This result indicates the superiority of the developed model in evaluating the storage capacity of the potential location for groundwater dam construction without the numerical simulation. Therefore, a more objective and efficient comparison for the storage capacity between the different potential locations can be possibly made based on the developed estimation model. In line with this, the proposed method can be an effective tool to assess the optimal location of groundwater dam construction across Korea.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.6
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• pp.213-219
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• 2007

This study was intended to estimate of relative compaction on the ground under the load using of portable FWD. The outcome in the wake of the study is highlighted as below. Viewing the variation of dynamic deflection modulus depending on a number of compaction, when a number of compaction increased to 8 (18.3MPa) from 4 (15Mpa), a dynamic deflection modulus increased 27%, and when a number reached to 12 (27.9MPa), it doubled the value indicated in 4. Viewing the relationship between dry density and dynamic deflection modulus in line with the increase in a number of compaction, a number of compaction by the roller reaching to the degree of compaction equivalent to 95% of max dry density was 13, with a dynamic deflection modulus indicating 27MPa ~ 29MPa.

• The Journal of Korea Robotics Society
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• v.4 no.2
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• pp.139-146
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• 2009

This paper describes how a person extracts a unknown object with pointing gesture while interacting with a robot. Using a stereo vision sensor, our proposed method consists of two stages: the detection of the operators' face, the estimation of the pointing direction, and the extraction of the pointed object. The operator's face is recognized by using the Haar-like features. And then we estimate the 3D pointing direction from the shoulder-to-hand line. Finally, we segment an unknown object from 3D point clouds in estimated region of interest. On the basis of this proposed method, we implemented an object registration system with our mobile robot and obtained reliable experimental results.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.11 no.1
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• pp.1-9
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• 2012

In this paper, we proposed a method of improving the location estimation error existing in RTLS (Real Time Location Service) system for the individual mobility. As ubiquitous age comes, interest for indoor location tracking system is getting more increased. However, existing indoor location tracking system does not correspond actively to frequent changes in indoor environment, and there is a problem that correct location measurement of moving object is difficult due to NLOS (non-line-of-sight) property of indoor environment. Purpose of this paper is to propose an environment accommodation location tracking system that improves the location precision of moving object and grasps location of the object effectively, which is essential an element effectively to provide service and satisfy various users' request.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2498-2501
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• 2003

In this paper, we present a wavelet neural network (WNN) approach to the solution of the path tracking problem for mobile robots that possess complexity, nonlinearity and noise. First, we discuss a WNN based control system where the control signals are directly obtained by minimizing the difference between the reference track and the pose of a mobile robot. This compact network structure is helpful to determine the number of hidden nodes and the initial value of weights. Then, the data with various noises provided by odometric and external sensors are here fused together by means of an Extended Kalman Filter (EKF) approach for the pose estimation problem of mobile robots. This control process is a dynamic on-line process that uses the wavelet neural network trained via the gradient-descent method with estimates from EKF. Finally, we verify the effectiveness and feasibility of the proposed control system through simulations.