• Journal of information and communication convergence engineering
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• v.14 no.3
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• pp.153-162
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• 2016

Microwave and millimeter waves are considered suitable frequency ranges for diverse applications. The prediction of rain attenuation required the 1-min rainfall rate distribution, particularly for data obtained locally from experimental measurement campaigns over a given location. Rainfall rate data acquired from Korea Meteorological Administration (KMA) for nine major sites are analyzed to investigate the statistical stability of the cumulative distribution of rainfall rate, as obtained from a 10-year measurement. In this study, we use the following rain rate conversion techniques: Segal, Burgueno et al., Chebil and Rahman, exponential, and proposed global coefficient methods. The performance of the proposed technique is tested against that of the existing rain rate conversion techniques. The nine sites considered for the average 1-min rain rate derivation are Gwangju, Daegu, Daejeon, Busan, Seogwipo, Seoul, Ulsan, Incheon, and Chuncheon. In this paper, we propose a conversion technique for a suitable estimation of the 1-min rainfall rate distribution.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.4
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• pp.38-51
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• 2007

This paper describes research results for the measurement and analysis method of magnetic signatures generated from the ship's magnetic mock-up model. In this paper, we present the theoretical and experimental techniques for the separation of the permanent and the induced magnetic field from the measured magnetic signature of the mock-up model. Also, we describe the prediction method of the induced magnetic field generated from mock-up model using the Magnet s/w, one of the FEM analysis tools for the electro-magnetic field and the magnetic dipole modelling method based on the least square techniques. The proposed modelling and analysis methods can be used for the prediction and the analysis of the static magnetic field generated from the real naval ship as well as the mock-up model.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.5
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• pp.710-715
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• 2010

This study developed an automatic tool change system of the SMA-based tool clamping device for applications of micro-machine tools. This paper first describes clamping and unclamping procedures of the automatic tool change system and its basic configuration. Second, it presents fabrication techniques of components, such as a heating/cooling system and a tool loader. Finally, it describes automatic tool change test conducted with a prototype in which the fabrication techniques of components were employed. As the results of the test, times needed for clamping and unclamping operations were estimated to 18(s) and 8(s) respectively. The experimental results confirm that the proposed automatic tool change system can be sucessfully applied to micro-machine tools.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.836-841
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• 2002

This paper is concerned with the development of remote control and measurement systems system using the internet. Recently, various techniques are developed based on the advance of the internet environment. In this study, we developed the remote control and measurement system using the internet server programming technique, stepper motor control and the data acquistion programming techniques. Hence, we can perform measurement and control remotely. The feasibility of the system is validated using the experimental setup. A personal computer is equipped with the stepping motor controller which control the weight and the A/D board which measures the strain of the beam, server program was then installed on the PC and can be accessed through internet.

• Tribology and Lubricants
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• v.14 no.4
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• pp.79-87
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• 1998

Morphological analysis of wear particles in the lubricating oil is a very effective and versatile means of lubricant analysis for machine condition monitoring and fault diagnosis. The prospects for determining quantitative information about wear particle morphology have been considerably enhanced by recent developments reported in the application of image processing and analysis techniques. This study was undertaken to investigate the influence of oiliness agent and extreme pressure agent on the shape of wear particles. The wear test was performed under different experimental conditions with stearic acid, dibenzyl disulfide(DBDS) and tricresol phosphate(TCP) in paraffinic base oil. Wear particles characteristics were described using four shape parameters, namely 50% volumetric diameter, aspect, roundness and reflectivity. The results showed that the four shape parameters of wear particles depend on a kind of the additives. This analysis of wear debris with computer image processing techniques is sufficient to distinguish some types of wear debris. The wear volume of three kinds of the specimens are affected by the additives with boundary films.

• Korean Management Science Review
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• v.23 no.2
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• pp.75-91
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• 2006

The purpose of this paper is to propose a new software development cost estimation method using SVR(Support Vector Regression) SVR, one of machine learning techniques, has been attracting much attention for its theoretic clearness and food performance over other machine learning techniques. This paper may be the first study in which SVR is applied to the field of software cost estimation. To derive the new method, we analyze historical cost data including both well-known overseas and domestic software projects, and define cost drivers affecting software cost. Then, the SVR model is trained using the historical data and its estimation accuracy is compared with that of the linear regression model. Experimental results show that the SVR model produces more accurate prediction than the linear regression model.

• Journal of the Korean Society of Combustion
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• v.8 no.1
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• pp.36-45
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• 2003

The subject of turbulent premixed flames has been focused by many researchers for a number of decades. Especially, Borghi suggested a magnificent diagram classifying turbulent combustion areas and Lipatnikov and Chomiak modified this diagram. Recently, experimental techniques have been developed so that we can use PIV for measuring 2D velocity field and apply OH PLIF techniques for obtaining flame locations. In present study, a new diagram is proposed using strain rates and OH signal intensity. Thus, simultaneous PIV and OH PLIF measurements are used for shear strain rates and flame locations, respectively. It is believed that the shear strain rates represent flow characteristics such as turbulence intensity and the OH intensity indicates the flame characteristics such as burning velocities.

• Proceedings of the KOSOMBE Conference
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• v.1990 no.11
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• pp.29-32
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• 1990

The method for enhancing the edges from medical images is described. The various methods are tested for the medical Images contaminated by noises, such as weighted averaging based on local probabilities, unsharp masking techniques, and proposed combined techniques. As a result, the combined technique using the median filtering and edge masks in six directions is well suited to remove the noises as to as to preserve the edges. Experimental results and computational procedures are presented.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1422-1424
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• 2004

Various deterioration diagnostic techniques and devices are suggested, and most of which measure leakage current components as an indicator of arrester ageing. However, the techniques based on the magnitude of leakage current measure simply RMS or peak value of leakage current components and do not provide detailed information needed in the diagnosis. In this study, we found that the phase vs. wave height of total leakage current is changed or a new wave height is produced with arrester ageing. To complete the new technique, we designed an arrester diagnostic device which is composed of a current detection circuit, an optical transmission circuit, and an analysis program. After measurement of the total leakage current, magnitudes, phase vs. wave height, and harmonics of the leakage current components are analyzed by the microprocessor based device. From the experimental results, we confirmed that the device can measure most parameters needed for the arrester diagnostics and analyze an initial deterioration state.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.688-693
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• 2002

Adhesive bonding is becoming one of the popular joining techniques in metal industries, since it has some advantages over other techniques such as welding and diffusion bonding, e.g., any dissimilar metals are easily adhesive-bonded together. In this study, the experiments were carried out in order to provide the statistical data with strength evaluation methods: tension, shear and four-point bending tests for thermoplastic epoxy resin based adhesive-bonded metal joints. We should certificate on the probability of the adhesive strength that has the tendency of brittle fracture, the adhesive bonding strength between metals with thermoplastic adhesive has the best probability at four-point bending test. The strength testing method that has higher probability is four-point bending test, shear test and tensile test in order.