• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.660-667
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• 2000

This paper aims at analyzing the traffic of CDMA base station. RTD(Round Trip Delay) method, used for the study, is one of the developed tool for calculating the call setup time between the BTS(Base Station TransceiverSubsystem) and mobile station.We compare the calculated call setup time in air with the field experiments.And we suggest the RTD method for dividing the traffic of the connected repeater from that of the BTS, andwe can testify it by the experiment which analyze the difference of the received time between the base stationand the repeater including the forced delay elements.

• ETRI Journal
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• v.41 no.1
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• pp.84-92
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• 2019

Recent advances in digital holography in the far-infrared region of the spectrum have demonstrated the potential use of digital holography in homeland security as a tool to observe hostile environments in which smoke, flames, and dust impair vision. However, to make this application practical, it is necessary to simplify the optical setup. Here, we show an off-axis, self-reference scheme that spills the reference beam out from the object beam itself and avoids the need for a complex interferometric arrangement. We demonstrate that this scheme allows the reconstruction of high-quality holograms of objects captured under visible as well as far-infrared light exposure. This could pave the way to the industrialization of holographic systems to enable users to see through fire. Moreover, the quantitative nature of the holographic signal is preserved. Thus, the reported results demonstrate the possibility to use this setup for optical metrology.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.63-73
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• 2001

This paper presents a process and operation planning system with an NC code post-processor for effective machining of press dies for production of cars. Based on the machining features, major parts of press dies are categorized into 15 groups and a standard process plan is defined for each group. The standard process plan consists of a series of processes where a process is defined as a group of operations that can be done with one setup. Details such as cutting tools, cutting conditions, and tool paths are decided at the operation planning stage. At the final stage of process and operation planning, the NC code post-processor we developed adjusts feedrates along the tool path to reduce machining time. The adjustment rule is selected based on the metal removal rate estimated by virtually machining with virtual cutting tool.

• IEMEK Journal of Embedded Systems and Applications
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• v.19 no.2
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• pp.83-90
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• 2024

CNC tools contribute to the production of high-precision and consistent results. However, employing damaged CNC tools or utilizing compromised numerical control can lead to significant issues, including equipment damage, overheating, and system-wide errors. Typically, the assessment of external damage to CNC tools involves capturing a single viewpoint through a camera to evaluate tool wear. This study aims to enhance existing methods by using only a single manually focused Microscope camera to enable comprehensive external analysis from multiple perspectives. Applying the NeRF (Neural Radiance Fields) algorithm to images captured with a single manual focus microscope camera, we construct a 3D rendering system. Through this system, it is possible to generate scenes of areas that cannot be captured even with a fixed camera setup, thereby assisting in the analysis of exterior features. However, the NeRF model requires considerable training time, ranging from several hours to over two days. To overcome these limitations of NeRF, various subsequent models have been developed. Therefore, this study aims to compare and apply the performance of Instant NGP, Mip-NeRF, and DS-NeRF, which have garnered attention following NeRF.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5B
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• pp.247-252
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• 2005

The testing tools implemented up to now for the LDAP(Light-weight Directory Access Protocol) interoperability tests are not easy to modify or add new test items since their source codes are not open. The object-oriented approach, therefore, is required to implement such a testing tool which can be easily modified or add new test items. Thus we designed the architecture for the testing tool applying the object-oriented approach. Java language, appropriate for the object-oriented approach, was used to implement the testing tool. The newly implemented testing tool can modify partly to adapt to the already stored data in the test suite information even during tests. Five LDAP servers can be tested simultaneously with the same configuration setup. Actual testing for the two LDAP servers validates the usefulness of the designed architecture with the proper working of the implemented testing tool according to the architecture.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.1
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• pp.1-8
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• 2006

Since most CAD tool companies are carrying out very expensive license policies, designers are sharing CAD tools with a limited number of licenses within a design working or research group. It is important to share and use them efficiently, because CAD tool licenses are very valuable resources. Designers should know CAD tool license information such as available number of licenses, types, and configuration methods to use CAD tools properly in their group. Usually, this information is provided by managers who administrate CAD tool license servers in the specific design group. In the previous CAD tool licenses sharing methods, designers have to get CAD tool license information manually and setup the environments with their own hands, If a new designer comes into the design working group, the designer wastes unnecessary time and effort due to these manual processes. As a result, designer's productivity and utilization of CAD tools will decrease. Besides, managers also waste their time and effort, since they should provide CAD tool license information manually to each desiEner. In this paper, we present a more efficient scheme to share CAD tool licenses based on directory service. The proposed method automates not only the communication processes between managers and designers, but also the license configuration steps. We expect this scheme will reduce time and effort of designers and managers as well as enhance the utilization of CAD tools.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.6
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• pp.615-621
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• 2013

The robot calibration has greatly improved the absolute accuracy of the industrial robot. However, the accuracy of the relative positions of robotic tool-tip at work-points on a work-piece is only slightly corrected by the robot calibration since there has been no practical method to eliminate the elements of the setup position errors at a robotic workplace. A robotic workplace calibration is demonstrated in this paper to minimize the relative position errors between a robot tool-tip and the work-point on a work-piece. The existing teaching and playback method has been developed for the robotic workplace calibration. This paper uses the work-piece fixed in a robotic work-place as measurement equipment instead of a special robot measurement equipment for the robotic workplace calibration. The positive effect of the robotic workplace calibration is supported by the results of computer simulation on an ideal robotic workplace model and an experiment at the actual robotic workplace.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.660-663
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• 1997

In recent manufacturing process, the increase of productivity is required by reducing machining time with the increase of cutting force. However, the excessive increase of cutting force can cause tool breakage, and have a bad effect on both the manufacturing machine and the workpiece. Thus, it is necessary to estimate and control cutting force in real time during the process. In this study, use of disturbance observer is proposed for the indirect cutting force estimation. The estimated cutting force is used for the real time control of feedrate, making the actual cutting force follow the reference force command. Since the suggested method does not need an expensive sensor like a dynamometer, the method is expected to be used practically. By reducing the machining time resulting from making the actual cutting force follow the reference force, the increase of productivity are also expected, and the quality of cutting surface has been improved due to the adjusted feedrate. Besides, an actual constant cutting force guarantees the prevention of tool breakage. To show the effectiveness of the suggested cutting force control method, an experimental setup has been made without the force sensor, applied to several workpieces. Experiments show that the suggested method is superior to the conventional method operated by constant feedrate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6C
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• pp.659-667
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• 2003

IPsec refers to a standardized set of security protocols and algorithms which can provide the integrity, the authentication and the confidentiality services for IP packets in the Internet. Between two security gateways, IPsec provides the access control, the connectionless Integrity, data origin authentication, the anti-replay, and the confidentiality services, not only to the IP layer but also to the upper layers. In this paper, we describe a VPN (Virtual Private Network) testbed configuration using the FreeS/WAN and analyze the ISAKMP messages exchanged between the linux security gateway during the IKE SA setup. Also, we describe our development of an IPSEC encryption verification tool which can be used conveniently by VPN administrators.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.183-187
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• 1996

On the machine measuring system composed of touch trigger probes, a DNC module, a CMM module, an analysis module and a man-machine interface unit was developed. Measuring accuracy is affected by working accuracy of the on the machine measuring system. The working accuracy of the system is due to geometric errors of th machine tool, servo errors of feed drives and positioning errors of probes. In order to compensate for the measuring errors due to the working accuracy, a calibration module was developed. The measuring automation system was realized with the on the machine measuring system and an IBM-PC on the machine center through a RS-232C. It turns the machining machine (CMM). The system is used for dimensional checking of machined components. initial job setup, part identification, identification of machining errors due to deflection and wear of tools. cutter run out, and calibration of machine tools. A horizontal machining center equipped with FANUC OMC wre used for verification of the system. The validity and reliability of the system. The validity and reliability of the system were confirmed through a series of experiments with gage blocks, ring gages, comparison measurement with a commercial CMM, and so on.