• Journal of the Korean Society of Safety
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• v.37 no.4
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• pp.1-10
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• 2022

The purposes of this study were to suggest 1) a future direction for Korea's machine tool industry and 2) how to secure the safety and reliability of emerging intelligent or automated machine tooling. The study concludes that, overseas, the machine tool industry is growing again while promoting innovation by converging with ICT. Accordingly, Korea also promotes ICT innovation to advance the machine tool industry, which is at the core of the national economy. As a result, unlike in the past, the frequency of serious injuries like entrapment accidents has recently decreased, while the proportion of collision accidents has increased. In addition, a new type of accident has become possible. Since ICT is network-based, the distinction between work and rest can become ambiguous; there is a risk of hacking, working hours and places are flexible and there are risk factors for diseases like chronic fatigue due to overload of specific personnel. As robots and automation are introduced, there is also a high probability of problems caused by physical and psychological burdens on system operators and resulting fatigue.

• Wind and Structures
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• v.36 no.6
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• pp.355-366
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• 2023

Although machine learning (ML) techniques have been widely used in various fields of engineering practice, their applications in the field of wind engineering are still at the initial stage. In order to evaluate the feasibility of machine learning algorithms for prediction of wind loads on high-rise buildings, this study took the exposure category type, wind direction and the height of local wind force as the input features and adopted four different machine learning algorithms including k-nearest neighbor (KNN), support vector machine (SVM), gradient boosting regression tree (GBRT) and extreme gradient (XG) boosting to predict wind force coefficients of CAARC standard tall building model. All the hyper-parameters of four ML algorithms are optimized by tree-structured Parzen estimator (TPE). The result shows that mean drag force coefficients and RMS lift force coefficients can be well predicted by the GBRT algorithm model while the RMS drag force coefficients can be forecasted preferably by the XG boosting algorithm model. The proposed machine learning based algorithms for wind loads prediction can be an alternative of traditional wind tunnel tests and computational fluid dynamic simulations.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.150-155
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• 1997

Rapid Prototyping(RP) is the technique which is used to make prototypes or functional parts directly using the 3-D solid data. Before building the prototype, several processes such as transfering 3D data from CAD system(STL) determination of build-direction, adding support structure and slicing are required. Among the above processes. determination of build-direction is the target of this study. The build direction is determined by many factors according to the objective of the user, like part accuracy, number of support structure, build time, amount of trapped volume, etc, But it is not easy to determine the build-direction because there are many factors and some factors have dependent properties with one another. So, in this study the part accuracy, the number of support structures and build time are considered as the main factor to determine the optimal build-direction. To determine the optimal build-direction for increasing part accuracy, sum of projected area which caused stairstepping effect was considered. The less the projected area is the better part accuracy is About the optimal build-direction to minimize the amount of support structure, sum of projected area of facets that require support structures was considered. About the build time, we considered the minimum height of part we intended. About the build time, we considered the minimun height of part we intended to make.

• Journal of Biosystems Engineering
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• v.28 no.2
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• pp.127-136
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• 2003

The top-to-bottom compression strength of corrugated board box is the most important mode of loading during it's no, and it depends largely on the edgewise compression strength of the corrugated board in the cross-machine direction and to a considerable extent on the flexural stiffness in both principal directions (CD; cross-machine direction, MD; machine direction) of the corrugated board. Corrugated board is a sandwich structure with an orthotropic property. The purpose of this study was to elucidate the principal design parameters for board combination of corrugated board from the viewpoint of bending strength through the finite element analysis [FEA] fur the various corrugated board. In general, the flexural stiffness [FS] in the MD was 2-3 times larger than that in the CD, and the effect of liner for the FS of corrugated board was much bigger than that of corrugating medium. The flexural stiffness index [FSI] was high when the stiffness of liner was in the order of inner, outer, and middle liner in double-wall corrugated board [DW], and the effect of the stiffness arrangement or itself reinforcement of corrugating medium on the FSI was not high. In single-wall corrugated board [SW] with DW. the variation of FSI with itself stiffness reinforcement of liner was much bigger than that with stiffness arrangement of liner. The highest FSI was at the ratio of about 2:1:2 for basis weight distribution of outer, middle, and inner liner if the stiffness of liner and total basis weight of corrugated board were equal in DW Secondarily. basis weight was in the order of inner, outer, and middle liner. However, the variation of FSI with basis weight distribution between liner and corrugating medium was much bigger than that with itself basis weight distribution ratio of liner and corrugating medium respectively in both DW and SW. md the FSI was high as more total basis weight was divided into liner. These phenomena fur board combination of corrugated board based on the FEA were well verified by experimental investigation.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.724-730
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• 2011

A turnout serves to switch train from one line to another. The turnout consists of a Point which is switchs the rail to induce direction, and a Crossing which is cross over two line on the plane surface, and a Lead where is middle section in Point to Crossing. Point machine, consists of a turnout, is important facilities in railway signal, that is safety issue relates in derailment of the train. Recently, train delay and accident frequently occurred because of the turnout include in a point machine trouble of electrical and mechanical. So in order to prevent train accident the research is advanced, install of normal and reverse indication lamp in a point machine, development of adherence detector for sensing the status of adhesion between the stock rails and tongue rails etc. In this paper investigates the problem which is connected with a turnout trouble, include in a point machine, occurrence at the time of train accident, and then proposed to the safety system model in order to prevent the train accident in turnout.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1005-1008
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• 1995

The spindle is a very important part of machine tool. The evaluation of spindle motion is required for improving the performance of machine tools. The evaluation tools have been developed for precison spindle by the reversal technique, and 3D error map motion of spindle is proposed. This technique makes us understand the total movement of spindle more easily. The proposed technique has been successfully applied to practical machine tools, giving high potentials for the spindle performance measurement.

• Journal of the Korea Convergence Society
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• v.1 no.1
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• pp.49-55
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• 2010

As the developing of the information communication technology, more and more devices are with the capacity of communication and networking. The convergence businesses which communicate with the devices have been developing rapidly. The IT convergence communication is viewed as one of the next frontiers in wireless communications. In this paper, we analyze detailed security threats against M2M(Machine to Machine), intelligent vehicle, smart grid and u-Healthcare in IT convergence architecture. We proposed a direction of the IT convergence security that imbedded system security, forensic security, user authentication and key management scheme.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.12
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• pp.34-41
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• 2003

This paper suggests a methodology fur improving the machining accuracy by compensating for the machining errors based on on-machine measurement process. Probing errors and machine tool errors included in the measurement data were calibrated or compensated to obtain the actual machining errors. Machine tool errors were modeled in forward and backward directions according to the axis movement direction to consider the effects of backlash errors on the measurement data, and model parameters were determined by measuring a cube array artifact. A rectangular workpiece was machined and then measured with a touch probe as a verification experiment. Machining experiments showed that the machining errors were reduced to within the designated tolerance after compensating for the actual machining errors by modifying the original footpath for the next-step machining.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.10
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• pp.501-506
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• 2003

A Superconducting Rotary Machine (SRM) is characterized by an air-cored machine with its rotor iron and stator iron teeth removed. For this reason, the SRM is featured by 3D magnetic flux distribution, which decreases in the direction of axis. Therefore, 3D magnetic field analysis method is required to know about characteristic of magnetic field distribution of SRM. In this paper, 3D flux distribution of SRM is calculated by analytical method. The magnetic field distribution of the field coils is calculated by Biot-Savart equation. The magnetic core is represented by magnetic surface polarities. This paper describes the combined use of above methods for the total field computation, and compares results of analytical method and 3D FEM(Finite Element Method).

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.604-606
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• 1998

As a basic study for Man-Machine interfacing technics, this paper purposed the vertorization of EOG(electrooculogram) that is generated by eye movement. EOG is electric potential difference between the positive potential of cornea and the negative potential of retina. The magnitude and the polarity are depend on the direction of eye movement and degree of gaze angle. In order to vectorize EOG, EOG signal is measured about vertical and horizontal movement of eyes. This vectorization of EOG is expected to help Man-Machine Interfacing technics and development of other useful equipment.