• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.207-213
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• 2023

Computed tomography (CT) images are used as the basis for proton Bragg peak position estimation and treatment plan simulation. During the Hounsfield Unit (HU) based proton stopping power ratio (SPR) estimation, small differences in the patient's density and elemental composition lead to uncertainty in the Bragg peak positions along the path of the proton beam. In this study, we investigated the potential of dual-energy computed tomography image-based proton SPRs prediction accuracy to reduce the uncertainty of Bragg peak position prediction. Single- and dual-energy images of an electron density phantom (CIRS Model 062M electron density phantom, CIRS Inc., Norfolk, VA, USA) were acquired using a computed tomography system (Somatom Definition AS, Siemens Health Care, Forchheim, Germany) to estimate the SPRs of the proton beam. To validate the method, it was compared to the SPRs estimated from standard data provided by the National Institute of Standards and Technology (NIST). The results show that the dual-energy image-based method has the potential to improve accuracy in predicting the SPRs of proton beams, and it is expected that further improvements in predicting the position of the proton's Bragg peak will be possible if a wider variety of substitutes with different densities and elemental compositions of the human body are used to predict the SPRs.

• Safety and Health at Work
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• v.6 no.3
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• pp.206-210
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• 2015

Background: Fatigue has a strong impact on workers' performance and safety, but expedient methods for assessing fatigue on the job are not yet available. Studies discuss posturography as an indicator of fatigue, but further evidence for its use in the workplace is needed. The purpose of the study is to examine whether posturography is a suitable indicator of fatigue in clerical workers. Methods: Thirty-six employees (${\emptyset}$ 34.8 years, standard deviation = 12.5) participated in postural tasks (eyes open, eyes closed, arm swinging, and dual task) in the morning and afternoon. Position of their center of pressure (COP) was registered using a Nintendo Wii Balance Board and commercial software. From registered COP time series, we calculated the following parameters: path length (mm), velocity (mm/s), anterior-posterior variance (mm), mediolateral variance (mm), and confidence area ($mm^2$). These parameters were reduced to two orthogonal factors in a factor analysis with varimax rotation. Results: Statistical analysis of the first factor (path length and velocity) showed a significant effect of time of day: COP moved along a shorter path at a lower velocity in the afternoon compared with that in the morning. There also was a significant effect of task, but no significant interaction. Conclusion: Data suggest that postural stability of clerical workers was comparable in the morning and afternoon, but COP movement was greater in the morning. Within the framework of dynamic systems theory, this could indicate that the postural system explored the state space in more detail, and thus was more ready to respond to unexpected perturbations in the morning.

• 재활복지
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• v.22 no.3
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• pp.41-68
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• 2018

The purpose of this study was to verify the causal relations among related factors of job and life satisfaction among 805 wage workers with disabilities. The study conducted a path analysis using the $8^{th}$ Panel survey of Employment for the Disabled data. The results are as follows. Firstly, the life satisfaction scale was categorized into the human relationship satisfaction and the material environment satisfaction by an explorative factor analysis. These two satisfactions are directly affected by Job Satisfaction (JS) and Job Involvement (JI), not directly affected by Job Engagement (JE). Secondly, JS and JI have a complete mediated effect on the path from JE to these two satisfactions. Thirdly, an indirect effect in the path reaching JS was shown to be significant in a dual mediating effect through JS and JI. Based on this study, it is recommended the way of vocational rehabilitation counseling and the related supporting strategies and programs devise toward a JS of wage workers with disabilities, vocational rehabilitation field practitioners and professionals should consider properly intervening job factors.

• Korean Journal of Culture and Social Issue
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• v.19 no.1
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• pp.45-68
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• 2013

In this study, We examined the dual path model in which entitlement rage and sexual dominance on the one of two pathway, sexual permissiveness and sexual objectification on another pathway mediated the relation between narcissism and sexual aggression. In addition, it was investigated whether alcohol use and rape myths acceptance have moderating effects in the pathways from sexual dominance and sexual objectification to sexual aggression on our path model. Data from 368 male college students in four university in Chungcheong province were analyzed using structural equation modeling. Results in structural equation modeling exhibited that narcissism affected sexual aggression through mediating effects of entitlement rage and sexual dominance, and through mediating effects of sexual permissiveness and sexual objectification. Furthermore, alcohol use and rape myths acceptance only moderated the relation between sexual dominance and sexual aggression on our model. We discussed the meaning of results and the implications for further study.

• The Journal of the Korea Contents Association
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• v.14 no.1
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• pp.435-443
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• 2014

The aim of this study was to look for the cause of shortage of K-League spectators from a consumer's perspective and to offer solutions. For this, we offered enhancement method of the K-League spectators through dual path model based on existing relative researches. The first path involved consumer reaction to external factors of the K-League game. This path explained relational view(=we-ness) of consumers on K-League game(Hypothesis 1, 2). The second path explained personal view on K-League game. This path means consumer reaction to K-League game itself(Hypothesis 3, 4). The empirical study was based on a field survey and structural equation model. The results showed that we-ness positively affected team loyalty(Hypothesis 1) and the team loyalty positively affected spectating intentions(Hypothesis 2). It also revealed that flow of K-League game positively affected consumer satisfaction(Hypothesis 3). Finally consumer satisfaction was found to affect spectating intentions(Hypothesis 4). The significance of present study is to extend scope of research which is related with cheerleading of sports game. And this study emphasize the importance of we-ness and flow in sports game.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.165-169
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• 2004

Recently remote sensing technology is applied for construction projects planning and design areas by use of high resolution satellite images according to engineering application technology in the various experimental tasks. In this study, It was applied for optimum route selection methods and basic design by comparing to present railway and new expand dual railway route on the new construction plan path of 20km at national railway lines, and then showed 3-dimensional images and fly simulation images to possibility for various application as low cost and short time compare to airplane and helicopters survey methods. As a results of its applied, It gained the results not only improvement of present methods but also real various application possibilities.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.69-70
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• 2013

By using differential force between left and right wheel, lateral motion can be controlled known as Direct Yaw-moment Control (DYC). In previous researches, DYC control is proposed to increase the stability of the vehicle, but maneuverability has not been discussed sufficiently. The car handling condition which is called the index parameter of maneuverability is dependent on the vehicle velocity and steering angle. To achieve the desired vehicle's cornering path, the car handling condition must be considered sufficiently. In this paper, the novel DYC method is proposed which gives the car handling condition regardless of the longitudinal speed. The proposed controller is based on the PI controller to feedback the curvature parameter. The controlled system shows the advantages of DYC regarding to the reference trajectory by the dual motor system. With respect to the uncontrolled model, the effectiveness of the proposed method is validated by numerical examples.

• Transactions of Materials Processing
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• v.17 no.7
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• pp.517-522
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• 2008

A visco-plastic self-consistent (VPSC) polycrystal model has been applied to simulate texture simulation and anisotropic properties of DP steels during deep drawing process. In order to evaluate the strain path during deep drawing, a steady state was assumed in the flange part of deep drawn cup. The final stable orientations were strongly dependent on the initial location in the blank. The evolution of anisotropy of DP steel sheets has been demonstrated through comparison of plastic strain rate vector at the different plastic strain levels.

• Bulletin of the Korean Mathematical Society
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• v.53 no.6
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• pp.1831-1844
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• 2016

In this paper, we improve the full-Newton step infeasible interior-point algorithm proposed by Mansouri et al. [6]. The algorithm takes only one full-Newton step in a major iteration. To perform this step, the algorithm adopts the largest logical value for the barrier update parameter ${\theta}$. This value is adapted with the value of proximity function ${\delta}$ related to (x, y, s) in current iteration of the algorithm. We derive a suitable interval to change the parameter ${\theta}$ from iteration to iteration. This leads to more flexibilities in the algorithm, compared to the situation that ${\theta}$ takes a default fixed value.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.2
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• pp.303-311
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• 1996

The Self Healing Ring (SHR) is one of the most Intriguing schemes which provide survivability for telecommunication networks. To design a cost effective SONET ring it is necessary to consider load balancing problems by which the link capacity is determined. The load balancing problem in SONET ring when demand splitting is not allowed is considered in this paper. An efficient algorithm is presented which provides the best solution starting from various Initial solutions. The initial solution is obtained by routing ell demands such that no demands pass through an are In the ring. The proposed algorithm iteratively improves the Initial solution by examining each demand and selecting the maximum load are in its path. The demand whose maximum arc load is biggest is selected to be routed in opposite direction. Computational results show that the proposed algorithm is excellent both in the solution quality and in the computational time requirement. The average error bound of the algorithm is 0.11% of the optimum and compared to dual-ascent approach which has good computational results than other heuristics.