• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.757-762
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• 2007

The lining segment which is the main structure of the shield tunnel consists of joints, not continua. Past international and domestic design data have been commonly used for design practices without specific verification about the structural analysis model, design load, and affection of the soil constant of the lining segment. In this study, the propriety is estimated through the comparison between analytical solution and numerical solution for segment analysis and design models of the shield tunnel which is being used internationally and domestically. As a result, the full. circumferential beam jointed spring model (1R-S0) is suggested by considering aspects of convenient use, application to field condition, and accuracy of analysis result. With suggested model, the parameter analysis was conducted for joint stiffness, ground rigidity, joint distribution, and joint number.

• Archives of Plastic Surgery
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• v.44 no.3
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• pp.223-227
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• 2017

Background Carpal tunnel release is one of the most common surgical procedures performed by hand surgeons. The authors created a surgical simulation of open carpal tunnel release utilizing a mobile and rehearsal platform app. This study was performed in order to validate the simulator as an effective training platform for carpal tunnel release. Methods The simulator was evaluated using a number of metrics: construct validity (the ability to identify variability in skill levels), face validity (the perceived ability of the simulator to teach the intended material), content validity (that the simulator was an accurate representation of the intended operation), and acceptability validity (willingness of the desired user group to adopt this method of training). Novices and experts were recruited. Each group was tested, and all participants were assigned an objective score, which served as construct validation. A Likert-scale questionnaire was administered to gauge face, content, and acceptability validity. Results Twenty novices and 10 experts were recruited for this study. The objective performance scores from the expert group were significantly higher than those of the novice group, with surgeons scoring a median of 74% and medical students scoring a median of 45%. The questionnaire responses indicated face, content, and acceptability validation. Conclusions This mobile-based surgical simulation platform provides step-by-step instruction for a variety of surgical procedures. The findings of this study help to demonstrate its utility as a learning tool, as we confirmed construct, face, content, and acceptability validity for carpal tunnel release. This easy-to-use educational tool may help bring surgical education to a new- and highly mobile-level.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.53-54
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• 2006

The main purpose of tunnel ventilation system is to maintain CO pollutant and VI (visibility index) under an adequate level to provide drivers with safe driving condition. Moreover, it is necessary to minimize power consumption used to operate ventilation system. To achieve the objectives, the control algorithm used in this research is reinforcement teaming (RL) method. RL is a goal-directed teaming of a mapping from situations to actions. The goal of RL is to maximize a reward which is an evaluative feedback from the environment. Constructing the reward of the tunnel ventilation system, two objectives listed above are included. RL algorithm based on actor-critic architecture and natural gradient method is adopted to the system. Also, the recursive least-squares (RLS) is employed to the learning process to improve the efficiency of the use of data. The simulation results performed with real data collected from existing tunnel are provided in this paper. It is confirmed that with the suggested controller, the pollutant level inside the tunnel was well maintained under allowable limit and the performance of energy consumption was improved compared to conventional control scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.531-532
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• 2016

Carpal tunnel syndrome, carpal tunnel becomes part of a narrower median nerve pain occurs pressed. How a stable wrist stretch for the prevention of carpal tunnel syndrome is required, it should life guides to fit the user is provided. In this research, users themselves recognize the risk of carpal tunnel syndrome, to be able to stretch, it implements the application. Application, based on the usage time set by the user, executes the alarm and lock. At this time, the user may utilize arduino and inertia sensor, it is possible to wrist stretch, to analyze usage patterns, it is possible to provide a medical information and life guides to suit the user. Data using Bluetooth 4.0 communication has been to meet the runaway. In order to evaluate the mounted system, targeting four subjects, the time and the touch frequency of usage of the 3-day smartphone measured, as a result of the questionnaire, it reduces the frequency of use of smartphones, a positive it was possible to prove the effect.

• Geomechanics and Engineering
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• v.33 no.1
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• pp.101-112
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• 2023

When a submerged floating tunnel is connected to the ground, there is a risk of stress concentration at the shore connection owing to the displacement imbalance caused by low confinement pressures in water and high confinement pressures in the ground. Here, the effects of the boundary condition and stiffness of the joints installed at the shore connection on the behaviors of a submerged floating tunnel and its shore connection were analyzed using a numerical method. The analysis results obtained with fixed and ground boundaries were similar due to the high stiffness of the ground boundary. However, the stability of the shore connection was found to be improved with the ground boundary as a small displacement was allowed at the boundary. The effect of the joint stiffness was evaluated by investigating the dynamic behavior of the submerged floating tunnel, the magnitude of the load acting on the bored tunnel, and the stress distribution at the shore connection. A lower joint stiffness was found to correspond to more effective relief of the stress concentration at the shore connection. However, it was confirmed that joints with low stiffness also increase the submerged floating tunnel displacement and decrease the frequency of the dynamic behavior, causing a risk of increased resonance when wave loads with low frequency are applied. Therefore, it is necessary to derive the optimal joint stiffness that can achieve both stress concentration relief and resonance prevention during the design of shore connections to secure their dynamic stability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.133-133
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• 2009

It is desirable to choose a high-k material having a large band offset with the tunneling oxide and a deep trapping level for use as the charge trapping layer to achieve high PIE (Programming/erasing) speeds and good reliability, respectively. In this paper, charge trapping and tunneling characteristics of high-k hafnium oxide ($HfO_2$) layer with various thicknesses were investigated for applications of tunnel barrier engineered nonvolatile memory. A critical thickness of $HfO_2$ layer for suppressing the charge trapping and enhancing the tunneling sensitivity of tunnel barrier were developed. Also, the charge trap centroid and charge trap density were extracted by constant current stress (CCS) method. As a result, the optimization of $HfO_2$ thickness considerably improved the performances of non-volatile memory(NVM).

• Tunnel and Underground Space
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• v.12 no.2
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• pp.99-106
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• 2002

To use the early measured data of tunnel deformation in but analysis, the relationship between these values find final deformation data were studied. Panet\`s exponential and fraction equations successfully approximate the convergence of the hard rock tunnels. Measured deformation data of ID location, $U_{1D}$ show that they can be lilted to linear equations but should not be used to estimate potential deformation before measurement, $C_{0}$. Early measured data $U_{1D}$ $U_{2D}$ , and final deformation $ U_{L}$ showed linear correlations. It proved that estimated data of final deformation from early measured ones can be used as input parameters for back analysis.

• Economic and Environmental Geology
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• v.31 no.6
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• pp.535-545
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• 1998

Various geophysical methods have been applied to the survey of the lava tunnel of Manjanggul in Cheju Island to study the effectiveness of each method in investigating underground tunnels. The surveys employing gravity, magnetic, electrical, AMT and VLF methods were carried out along seven profiles across the Manjanggul; especially, all the five methods were used on one representative profile. Several aspects of different methods pertinent to their use in investigation of underground tunnels have been noted. The electrical method employing the dipole-dipole array appeared to be the most effective one among five methods. Therefore, we have tested the electrical method more carefully by using various electrode spacings, and obtained successful resistivity sections showing the existence of lava tunnels. The gravity method provided relatively successful responses associated with the tunnel although the gravity readings were contaminated by wind blowing during the survey. The gravity data were also useful for the quantitative modeling study. The magnetic data were also successful in delineating the tunnel qualitatively. The AMT data were not successful because the used frequency band was not appropriate in detecting very shallow target. The VLF data were severely influenced by the neighboring noise sources such as power lines and were not successful in detecting the tunnel responses. The comprehensive result of electrical, gravity and magnetic surveys suggests that undiscovered lava tunnels may exist adjacent to the Manjanggul.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2C
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• pp.83-92
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• 2011

Elastic modulus in rockmass is an important factor to represent the characteristic of rock deformation and is used to estimate the displacement due to tunnel excavation. Nevertheless, the study to estimate the elastic modulus, which condisiders the rock type and joint characteristics (joint shear strength and joint inclination angle), has been done in less frequency. Accordingly, this study is aimed at providing the method to estimate the elastic modulus of rockmass in the various rock and joint conditons and the results grasped from the study. For this purpose, the 2D discrete numerical analysis will be carried out and the displacements due to tunnel excavation will be investigated with the consideration of rock and joint conditions. Then the displacement results will be used to estimate the elastic modulus of rockmass in which rock and joint conditions are considered with the utilization of the elastic theory of circular tunnel. The results of elastic modulus, which considers the conditions of various rock and joint, would be expected to have a great practical use in field.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.65-73
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• 2004

In this paper, we propose a tunnel establishment scheme using Next Hop Resolution Protocol over mobile IP networks, which consist of LAN-based IP networks and ATM-based IP networks. As a basic idea, we use the shortest path algorithm to establish a short-cut tunnel between HA and FA. Also, we classify methods for establishing a short-cut tunnel into four cases considering the locations of HA, FA, CN and MN. To confirm the advantages of our schemes, which deliver packets using short-cut tunnel in optimized path method over mobile IP networks, we performed mathematical analysis and simulation, compared proposed schemes with existing IP routing method in terms of transmission delay between CN and MN. The simulation results show that our scheme have superior performance to that of existing IP routing mechanism, because the store-and-forward delay which occurred in IP routing mechanism is considerably reduced in short-cut tunnel over ATM networks.