• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.6
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• pp.34-40
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• 2004

This paper presents studies on curvature radius measurement using the laser interferometer. It is a general practice to measure to $10^{-10}$m in length with the recent improvement and innovations in measurement technology and the processor used. The measurement methods can generally be categorized as these two: the contactual method and non-contactual method; and in this study, we will find ways to lower the cost for a CMM, or a coordinate measurement machine, and try to find an alternative. Furthermore, we will discuss some of the ways to improve the non-contactual measurement methods-optical interferometer method and the optical triangulation method. We will measure an object using a laser distance measuring device and Set the Point-contact result with the ball-bearing type and line-contact result with the bearing type, to decide on which probe type will be used.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.201-206
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• 2004

Laser scanner are getting used for inspection and reverse engineering in industry such as motors, electronic products, dies and molds. However, due to the lack of efficient scanning technique, the tasks become limited to the low accuracy purpose. The main reasons for this limitation for usefulness are caused from the optical drawback, such as irregular reflection, scanning direction normal to measuring surface, the influence of surface integrity, and other optical disturbances. To overcome these drawback of laser scanner, this study propose the mechanism to reduce the optical trouble by using the 2 kinds of rotational movement axis and by composing the spherical coordinate to scanning the surface keeping normal direction consistently. So, it could be designed and interfaced the measuring device to realize that mechanism, and then it could acquisite the accurate 3D form cloud data. Also, these data are compared with the standard master ball and the data acquisited from the touch point sensor, to evaluate the accuracy and stability of measurement and to demonstrate the implementation of an dental tooth purpose system

• Construction Engineering and Management
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• v.4 no.1 s.13
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• pp.48-54
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• 2003

An automated system for scanning and characterizing unbound aggregates, called the 'Laser-based Aggregate Scanning System'(LASS), has been developed at the University of Texas at Austin. The system uses a laser profiler to acquire and analyze true three-dimensional data on aggregate particles to measure various morphological properties. Tests have demonstrated that the system can rapidly and accurately measure grain size distribution and dimensional ratios, and can objectively quantify particle shape, angularity, and texture in a size invariant manner. In its present state of development, the LASS machine is a first-generation, laboratory testing device. With additional development, this technology is expected to provide high-quality, detailed information for laboratory and on-line quality control during aggregate production.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.177-179
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• 1990

Recently, it is reported that the behaviour of PECVD under high electric field and current condition has a major effect on MNS device degradation. In this paper, we evaluated the breakdown and TDDB characteristics of Laser assisted PECVD SiN films which is introduced new deposited method. And also, long term insulator breakdown reliability is described by examing time dependent dielectric breakdown under positive voltage. Failure tines against electric field are examined and acceleration factors are obtained for each case. From these data, breakdown wearout limitation for Laser Assisted PECVD SiN film can be characterized.

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.91-96
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• 2000

We propose a novel in-line fiber optic circular polarizing mirror utilizing cholesteric lIquid crystal (CLC) polymer [11m for the fiber laser applications. Ions matrix representation of this device has been derived and venfied experimentally. In a Fabry-Perot cavity configuration, a CLC fiber optic rmrror has been used to achieve longitudinal mode suppression as well as to obtain passively mode~locked laser operations with 630 fs laser pulses via nonlinear polarization evoluhon.oluhon.

• ETRI Journal
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• v.26 no.1
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• pp.1-6
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• 2004

The photonic quantum ring (PQR) laser is a three dimensional whispering gallery (WG) mode laser and has anomalous quantum wire properties, such as microampere to nanoampere range threshold currents and ${\sqrt{T}}$-dependent thermal red shifts. We observed uniform bottom emissions from a 1-kb smart pixel chip of a $32{\times}32$ InGaAs PQR laser array flip-chip bonded to a 0.35 ${\mu}m$ CMOS-based PQR laser driver. The PQR-CMOS smart pixel array, now operating at 30 MHz, will be improved to the GHz frequency range through device and circuit optimization.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.75-78
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• 2002

Si thin films on p-type (100) Si substrate have been prepared by a pulsed laser deposition technique using a Nd:YAG laser. The pressure of the environmental gas during deposition was 1 Torr. After deposition, Si thin film has been annealed again at 400-840$^{\circ}C$ in nitrogen ambient. Strong blue photoluminescence (PL) have been observed at room temperature. We report the PL properties of Si thin films with the variation of the annealing temperature.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.537-543
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• 2014

RLG(Ring Laser Gyroscope) is a main device of LINS(Laser Inertial Navigation System). RLG has the lock-in region in which there is no output signal. To alleviate the lock-in problem, a mechanical oscillation, the dither motion, is applied on RLG. A LPF(Low Pass Filter) is usually used on the output of RLG and accelerometer to remove the noise that is made by the dither motion. When the LINS is induced the disturbance during the initial alignment, it takes more time on alignment due to the use of the LPF and a fixed gain controller. In this paper, an initial alignment using UKF(Unscented Kalman Filter) is designed and analysed. Analysis include comparison between conventional initial alignment loop using fixed gain type controller and proposed initial alignment using UKF. Moreover, Disturbance inducing test results are demonstrated.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.536-539
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• 2003

This paper presents a study of position tracing system for Underwater Vehicle Robots(UVR) that is inspecting an atomic furnace. This system development is the basic research for the purpose of position estimation of UVR and preventing that UVR crash into the wall of an atomic furnace. For this purpose, Pan/Tilt Unit that is attached Laser is pointing PSD(Position Sensitive Detector) Sensor which is stuck to the upper side of UVR. Through this action, we can find the Position of UVR. In this paper, we construct the system for aiming the laser pointer at PSD Sensor using pan/tilt and study the optimum algorithm for finding the optional position that is located at the space which is pointable area by Laser device.

• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.277-283
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• 2015

In this study, we evaluated the muscle tension in hemiplegia patients using a real-time monitoring system combined with high-intensity laser treatment (HILT) device. Five hemiplegia patients were treated with HILT in the left forearm muscle for 8 minutes, and the muscle was relaxed for 8 minutes following the treatment. Both the gradient of the force-displacement curves and the muscle hardness decreased during the therapy, and the effects were maintained following the treatment. The results show that muscle tension decreased rapidly during laser irradiation, and the efficacy of the treatment depended on the duration of the illness. Consequently, we conclude that this combined HILT and real-time muscle tension monitoring system is useful for evaluating the therapeutic procedure and for treatment of muscle pain.