• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.363-370
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• 2004

This Paper presents the response force distribution factor(RDF) and its application to recalculation of member forces in case of partial changes of structures. Using RDF, the mutuality of response forces between members can be estimated. The reanalysis technique recalculates directly any displacement or member force under consideration in real time without a full reanalysis in spite of local changes in member stiffness or connectivity using RDF. It is expected that RDF and the reanalysis technique can be used to develop efficient analysis techniques for tall buildings.

• International Journal of Advanced Culture Technology
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• v.9 no.3
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• pp.81-85
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• 2021

The purpose of this paper is to measure the relative efficiency of the police agencies in Korea with data collected from 2018 to 2020, using data envelopment analysis (DEA), as put forward by Charnes et al., which is used to construct a scalar measure of efficiency for all police agencies. The results of this study can be used to assist police agencies in delivering better and more efficient services to the community. The analytical results based on DEA identify potentially weak and strong police agencies on policing performance, their efficient benchmarking, and the levels of clear-ups that would make inefficient police agencies efficient. We could suggest that higher levels of the police force are associated with higher performance efficiency against crimes. But, it is a little hard to say that higher levels of the police force can keep the local police agencies efficient without explaining the contribution of other input variables to criminal arrest and prevention. On the other hand, our analysis presents that differences in operating environments and socioeconomic factors do not have a significant influence on the efficiency of local police agencies. But, it is necessary to note that we need to examine the effect of environments and socioeconomic factors on crime to create the better-policing performance.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.478-487
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• 1991

In this study, dynamic stability of discontinuous free Timoshenko beam, barring a concentrated mass, under constant follower force is considered. Governing differential equations are derived based on the extended Hamilton's principle and finite element method is applied for numerical analysis. Conclusions of the study are as follows : (1) Without force direction control, (i) the critical follower force at instability is increased with concentrated mass regardless of discontinuity. (ii) the minimum critical follower force is located in the vicinity of discontinuity position .xi.$_{d}$=0.75. (iii) at mass location .mu. .leq.0.5 the force at instability is decreased as magnitude of concentrated mass is increased but, at .mu. .geq. 0.5 the force is increased as the mass is increased. (2) With force direction control, (i) shear deformation parameter S contributes insignificantly to the force at instability when S>10$^{[-993]}$ (ii) maximum critical follower force can be obtained for the discontinuity location .xi.$_{d}$=0.25. (iii) the critical follower force is increased as magnitude of concentrated mass .alpha. is increased at mass location .mu. .geq.0.4, but is increased, .mu ..leq.0.4.4.

• Journal of Mechanical Science and Technology
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• v.20 no.7
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• pp.961-971
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• 2006

A deadweight force standard machine is a mechanical structure that generates force by subjecting deadweights to the local gravitational field. The Korea Research Institute of Standards and Science (KRISS) developed and installed a 100 kN deadweight force standard machine for national force standards. It can generate forces from 2 kN to 110 kN in increments of 1 kN. The uncertainty of the force machine was estimated and declared as $2\times10^{-5}$. This 100 kN deadweight force machine was compared with the 500 kN deadweight force standard machine at KRISS and the 20 kN and 50 kN deadweight force standard machines at the National Metrology Institute of Japan (NMIJ). The measurement results showed good agreement between the deadweight force machines, and the accuracy level of the 100 kN deadweight force machine was verified.

• Journal of the Korean Magnetics Society
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• v.13 no.2
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• pp.47-52
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• 2003

Ferromagnetic tunnel junctions were fabricated by dc magnetron sputtering and plasma oxidation process. The local transport properties of the ferromagnetic tunnel junctions were studied using contact-mode Atomic Force Microscopy (AFM) and the local current-voltage analysis. Tunnel junctions with the structure of sub./Ta/Cu/Ta/NiFe/Cu/Mn$\_$75/Ir$\_$25//Co$\_$70/Fe$\_$30//Al-oxide were prepared on thermally oxidized Si wafers. Al-oxide layers were formed with microwave excited plasma using radial line slot antenna (RLSA) for 5 and 7 sec. Kr gas was used as the inert gas mixed with $O_2$ gas for the plasma oxidization. No correlation between topography and current image was observed while they were measured simultaneously. The local current distribution was well identified with the distribution of local barrier height. Assuming the gaussian distribution of the local barrier height, the ferromagnetic tunnel junction with longer oxidation time was well fitted with the experimental results. As contrast, in the case of the shorter time oxidation junction, the current mainly flow through the low barrier height area for its insufficient oxygen. Such leakage current might result in the decrease of tunnel magnetoresistance (TMR) ratio.

• Journal of the Korean Electrochemical Society
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• v.9 no.2
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• pp.84-88
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• 2006

The effects of tip voltage, deflection setpoint, and tip velocity on height of $SiO_2$ line drawn by local anodization on Si wafer using scanning probe microscope were investigated. No local anodization was detected at smaller than -3 V of tip voltage. The line height increased at rate of 0.47 nm/V when the tip voltage is stronger than -3 V at $1{\mu}m/s$ tip velocity. From deflection setpoint, mechanical force between tip and substrate could be calculated and the threshold farce was $12\sim18nN$. The height of anodized $SiO_2$ lines is independent of the magnitude of force above the threshold force. The line height decreased as increasing the tip velocity and limited to 0.7 nm at -5 V tip voltage.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.1
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• pp.100-111
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• 1999

This paper resents a discrete-time model of an edge-following with accommodation force control. Since an irregular workpiece shape causes disturbances to the system while following an edge, the use of preview control is proposed to improve the system performance. The preview control employs future information of the workpiece contour shape, and it can be developed by LQ-optimal control principles. This study provides a general method how to utilize the local future information obtained by the finite preview to minimize an optimality criterion evaluated over a problem duration. The force controller is designed based on the preview control scheme, and then implemented on a VME-based computer. Experimental results using an industrial robot show that the preview control system achieves faster tracking speed and better force regulation than the conventional nonpreview control system.

• Journal of Korea Water Resources Association
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• v.51 no.3
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• pp.235-246
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• 2018

The main purpose of this study is to suggest a methodology for identifying vulnerable region in Choyang creek basin susceptible to soil losses based on runoff aggregation structure and energy expenditure pattern of natural river basin within the framework of power law distribution. To this end geomorphologic factors of every point in the basin of interest are extracted by using GIS, which define tractive force and stream power as well as drainage area, and then their complementary cumulative distributions are graphically analyzed through fitting them to power law distribution to identify the sensitive points within the basin susceptible to soil losses with respect to scaling regimes of tractive force and stream power. It is observed that the range of vulnerable region by scaling regime of tractive force is much narrower than by scaling regime of stream power. This result seems to be due to the tractive force is a kind of scale dependent factor which does not follow power law distribution and does not adequately reflect energy expenditure pattern of river basins. Therefore, stream power is preferred to be a more reasonable factor for the evaluation of soil losses. The methodology proposed in this study can be validated by visualizing the path of soil losses, which is generated from hill-slope process characterized by local slope, to the valley through fluvial process characterized by drainage area as well as local slope.

• Korean Security Journal
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• no.10
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• pp.149-171
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• 2005

In Korea, local autonomy police has been discussed several times since Liberation in terms of expanding the democracy of police, but this suggestion has not been pursued. However under the incumbent government, the local policing system will be fully implements from 2006, and the government says that it aims to introduce 'model management' from October this year. The model of local policing now in force is based on the national police and local police forces organized in parallel within local government autorities (cities, counties and districts). The heads of local autorities have the power to appoint local police. Of these, local authorities can use public servants working for the national police for 'special purposes'. The research questions for this study were to what extent public servants working for the national police in these circumstances can desire local autonomy police, and what factors influenced their decision to desire in local autonomy police. After analyzing the results of a survey of police officers, the study found that public servants working for the national police did not have great expectations of desire in local autonomy police. The factors that influenced the decision to desire in local autonomy police were the hope that remuneration would be good, and the hope that the atmosphere within the police force would become less bureaucratic and more democratic than the current system. The study also found that the hopes that promotions and working conditions would improve and that police would be treated better in society did not influence the decision of public servants working for the national police to desire in local autonomy police.

• Journal of Bio-Environment Control
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• v.2 no.1
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• pp.46-52
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• 1993

The wind pressure distributions were analyzed through the wind tunnel experiment to provide fundamental criteria for the structural design on the three-span arched house according to the wind directions. In order to investigate the wind force distribution, the variation of the wind force coefficients, the mean wind force coefficients, the drag force coefficients and the lift force coefficients were estimated from the experimental data. The results obtained are as follows : 1. The variation of the wind force with the wind directions on the side walls was the greatest at the upwind edge of the walls. The change of pressure from the positive to the negative on the side walls occurred at the wind direction of 30$^{\circ}$ in the first house and 60$^{\circ}$ in the third house. 2. The maximum negative wind force along the length of the roof appeared at the length ratio of 0-0.2, when the wind directions were 90$^{\circ}$ in the first house, 60$^{\circ}$ in the second house and 30$^{\circ}$ in the third house. 3. The maximum negative wind force along the width of the roof appeared at the width ratio and the wind direction of 0.4 and 0$^{\circ}$ in the first house, 0.4-0.6 and 30$^{\circ}$ in the second house and 0.6 and 30$^{\circ}$ in the third house, respectively. 4. The maximum mean positive and negative wind forces occurred at the wind direction of 60$^{\circ}$ and 30$^{\circ}$, respectively, on the side walls of the first house, and the maximum mean negative wind force on the roof occurred at the wind direction of 30$^{\circ}$ in third house. 5. The maximum drag and lift forces occurred at the wind direction of 30$^{\circ}$, and the maximum lift force appeared in the third house. 6. The parts to be considered for the local wind forces were the edges of the walls, the edges of the x-direction of the roofs, and the locations of the width ratio of 0.4 of the first and third house and the center of the width of the second house for the y-direction of the roofs.