• Structural Engineering and Mechanics
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• v.72 no.2
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• pp.191-201
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• 2019

Finite element analysis is one of the most used tools for studying femoral neck fracture. Nerveless, consensus concerning either the choice of material characteristics, damage law and /or geometric models (linear on nonlinear) remains unreached. In this work, we propose a numerical quasi-brittle damage model to describe the behavior of the proximal femur associated with two methods to evaluate the Young modulus. Eight proximal femur finite elements models were constructed from CT scan data (4 donors: 3 women; 1 man). The numerical computations showed a good agreement between the numerical curves (load - displacement) and the experimental ones. A very encouraging result is obtained when a comparison is made between the computed fracture loads and the experimental ones ($R^2=0.825$, Relative error =6.49%). All specific numerical computation provided very fair qualitative matches with the fracture patterns for the sideway fall simulation. Finally, the comparative study based on 32 simulations adopting linear and nonlinear meshing led to the conclusion that the quantitatively results are improved when a nonlinear mesh is used.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.458-459
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• 2021

Recently, researches using deep learning technology based on Wi-Fi fingerprints have been conducted for accurate services in indoor location-based services. Among the deep learning models, an RNN model that can store information from the past can store continuous movements in indoor positioning, thereby reducing positioning errors. At this time, continuous sequential data is required as training data. However, since Wi-Fi fingerprint data is generally managed only with signals for a specific location, it is inappropriate to use it as training data for an RNN model. This paper proposes a path generation method through prediction of a moving path based on Wi-Fi fingerprint data extended to region data through clustering to generate sequential input data of the RNN model.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.489-498
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• 2003

Recently to introduce new services of ultra-high speed wireless access and systems beyond the 3rd generation mobile communication, 5 GHz band has been highly interested. As a way of getting the required frequency, it is considered that microwave relay bands below 6 GHz, which shows a slow decrease in demand and less cost-effectiveness, should be moved to other bands above 6 GHz. In this paper, as a tool for analyzing microwave link design and its service quality, the outage prediction based upon Vigants & Barnett＇s model is reviewed. To show outage and availability calculation, simulations are performed for the operating 4 GHz radio sites, and some results and features regarding frequency movement to 6.7 as well as 8 GHz are also discussed in terms of diversity techniques, bit error rate, and availability As the results, it is confirmed that only the diversity techniques of space or space and frequency can satisfy the annual objective of availability irrespective of frequency movement.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.1
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• pp.56-66
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• 1999

Shoulder joint is the most movable joint in human body with, at least, three degrees of freedom, since there are at least three bones and five joints involved in shoulder movement. Due to the complexity of the shoulder joint and the lack of appropriate anatomical data, modeling of the shoulder joint has been known to be extremely difficult. In many biomechanical models being used, shoulder joint is considered as a fixed point and it is also assumed that the shoulder joint does not noticeably move during the shoulder movement. However, such an assumption is not valid in real applications and causes inaccuracy, especially, in the area of workspace evaluation. The reachable area generated by a human becomes somewhat different from that of current models for those models fail to appropriately reflect the movement of shoulder joint's center of rotation. In this study, the location of the shoulder joint's center of rotation was obtained in relation to the location of humerus, on which a new model for reach envelope generation was developed for workspace evaluation. From the experiments conducted for three subjects, the initial location of the center of rotation was determined for each subject and subsequent changes in the instantaneous center of rotation were drawn as a function of flexion and abduction of the shoulder. Based on the regression analysis, the study suggested a new method for the generation of reach envelope. Comparisons were also made among real reach envelopes obtained from the experiment, the ones from the model, and the ones from the new method suggested in the study. As a result, the prediction errors incurred from the new method were significantly reduced when compared to the ones from the current approach.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.462-469
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• 2010

Gas-liquid 2 phase processes are usually used in chemical, biochemical, environmental engineering and food process. For optimizing these processes, understanding bubble's precise movement and shape are needed. Bubble's movement and shape are effected by liquid's properties-viscosity, surface tension and bubble's properties-size, velocity. This paper deals with experimental data of bubble's movement and shape in high viscous silicone oil. Also, drag coefficient and deformation factor given by other researcher's papers and books are used to predicting and comparing bubble's terminal velocity, drag coefficient, deformation factor and shape with experimental value. Experimental data show that bubble moves faster when it moves in lower viscous silicone oil and it's drag coefficient is bigger when it moves in high viscous silicone oil. Bubble's shape is close to sphere when moving in high viscous silicone. Formulas proposed by Batchelor expect most accurate prediction for bubble's velocity and drag coefficient. Bubble's 2D shape predicted by Batchelor's energy balance, drag coefficient and deformation factor show excellent agreement with experimental bubble's 2D shape.

• Journal of Korean Association for Spatial Structures
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• v.7 no.4
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• pp.73-78
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• 2007

The surrounding ground was much transformed by the lateral movement on the soft ground, and consequently the stake basis was damaged. In this case the installed stake is ratted the passive stake, and is actively being researched. When the unevenly distributed load was applied on the stake, and thus the lateral ground pressure was operated, and then the lateral movement was occurred, and consequently the structure is influenced. However, prediction and mechanism for the relationship of piles and abutment deformation is not sufficient. In this paper, coupled three-dimensional finite element analysis, which can be described solid, plate and frame elements at the same time, is developed by the authors. The lateral movement of bridge abutment for the aspect ratio of steel piles on soft clay is clarified by using developed numerical analysis.

• The korean journal of orthodontics
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• v.48 no.1
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• pp.3-10
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• 2018

Objective: The purpose of this study was to predict the optimal bending angles of a running loop for bodily protraction of the mandibular first molars and to clarify the mechanics of molar tipping and rotation. Methods: A three-dimensional finite element model was developed for predicting tooth movement, and a mechanical model based on the beam theory was constructed for clarifying force systems. Results: When a running loop without bends was used, the molar tipped mesially by $9.6^{\circ}$ and rotated counterclockwise by $5.4^{\circ}$. These angles were almost similar to those predicted by the beam theory. When the amount of tip-back and toe-in angles were $11.5^{\circ}$ and $9.9^{\circ}$, respectively, bodily movement of the molar was achieved. When the bend angles were increased to $14.2^{\circ}$ and $18.7^{\circ}$, the molar tipped distally by $4.9^{\circ}$ and rotated clockwise by $1.5^{\circ}$. Conclusions: Bodily movement of a mandibular first molar was achieved during protraction by controlling the tip-back and toe-in angles with the use of a running loop. The beam theory was effective for understanding the mechanics of molar tipping and rotation, as well as for predicting the optimal bending angles.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1425-1432
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• 2013

This paper examines the applicability of the Width Function Instantaneous Unit Hydrograph (WFIUH) with a case study of Cheongmi River in South Korea. The parameter values of WFIUH can be physically determined compared to the lumped hydrologic models, which are typically accompanied by parameter estimation procedures with gage records. Assuming uniformly distributed rainfall, the hydrographs obtained with the WFIUH show good agreement with observed data and also the results from HEC-1. A simple investigation of the effect from the rainstorm movement with the WFIUH demonstrates the ability of the proposed model and the need to consider the rainstorm movement effect on the resulting hydrographs for prediction purposes.

• Fire Science and Engineering
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• v.15 no.1
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• pp.7-15
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• 2001

This paper describes the smoke filling process of a fire field model based on a self-developed SMEP (Smoke Movement Estimating Program) codo to the simulation of fire induced flows in the atrium space (SIVANS atrium at Japan) containing smoke radiation effect. The SMEP using PISO algorithm solves conservation equations for mass, momentum, energy and species, together with those for the modified k-$\varepsilon$ turbulence model with buoyancy term. Also it solves the radiation equation using the discrete ordinates method. The result of the calculated smoke temperature containing radiation effect has shown a better prediction than the result calculated by only convection effect in comparison with the experimental data. This seems to come from the radiation effect of $H_2$O and $CO_2$ gas under smoke productions. Thus, the consideration of the radiation effect under smoke in fire should be necessary in order to get more realistic result. Also the numerical results indicated that the smoke layer is developing at a rate of about 0.1 m/s. It would take about 450 seconds after starting the ultra fast fire of 560 kW that the smoke layer move down to 1.5m above the escape level.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.773-790
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• 2009

The Korea high speed train was launched from Seoul to Busan of 1st construction phase at 1st April, 2004. This huge project will be lead to a great change in korean society such as existing mode choice behavior change and the concentrating on KTX station zone lifestyle pattern's change. With the result to opening high speed train railway was diminished train journey time between Seoul to Busan from 4 hours 10 minute to 2 hours 40 minutes, and has been change population movement, favorite location of corporation headquarters, existing metropolitan transportation pattern and so on. In the middle of this study, I choose to analyse Seoul-Cheonan/Asan stations, Seoul-Deajeon stations, Seoul-Deagu stations, Seoul-Pusan stations. This study have a information to analyse among as like movement of population, status of employee structure, usage of land, movement inland transportation mode. I sure that this study will lead to helpful prediction both 2nd phase of Kyoung-bu high-speed railway and Ho-nam high-speed railway in advance.