• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.379-388
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• 2016

There are various system defects from weapons manufacturing due to the numerous production processes and various production environments. The first kind of defect is patent defects, which can be detected by visual inspection, functional testing, and existing quality control procedures during the manufacturing process. The second kind is latent defects, which cannot be detected though existing quality management approaches because of the complexity of the system and manufacturing process. To minimize the initial defect problems, environmental stress screening (ESS) is needed to detect the defects, remove them, and improve the product conditions based on the environmental stress conditions of temperature and vibration. We implemented a tool for quantitative ESS effectiveness analysis and profile design automation based on MIL-HDBK-344 and verified it using six scenarios with different temperature stress, vibration stress, and test designs.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.3 no.2
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• pp.87-90
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• 2007

It's important that detect early caries of deciduous and permanent teeth to prevent dental caries and prevserve teeth, especially on proximal surface of deciduous teeth. The reason is that their prominent pulp horn lead to pulp treatment easily due to rapid caries progression. There are conventional exploring, visual inspection and radiographic exam for early caries detection. But, the standard method for diagnosing dental caries is subject and cavitation may be accelerated during exploring procedure. Caries can be diagnosed up to 40% mineral loss with radiograph. $DIFOTI^{(R)}$ (Digital Imaging Fiber-Optic TransIllumination) is diagnostic imaging system for early caries detection using fiber-optic illumination. It is possible that remineralize the tooth surface without tooth preparation and conserve the tooth structure by using $DIFOTI^{(R)}$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.5
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• pp.97-103
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• 2002

The assessment of the condition of a transformer winding which is suspected of having suffered short circuit damage can be difficult. Conventional test such as winding resistance, magnetic current or insulation resistance will only detect damage if a permanent electrical fault exists. Visual inspection of windings necessitates the removal of oil and in many cases only a very small proportion of the winding can be seen. We describe the characteristic of LVI test system and methods to detect the deformation of windings in the power transformers. As the front rise time of recurrent-surge generator pulse less than 1000 ㎱ and the peak value of pulse is about 500 V, we have the good results of detecting winding deformation in the LVI test of transformers.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.2_2
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• pp.163-171
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• 2020

The condition of tire tread is a key parameter closely related to the driving safety of a vehicle, which affects the contact force of the tire for braking, accelerating and cornering. The major factor influencing the contact force is tread wear, and the more tire tread wears out, the higher risk of losing control of a vehicle exits. The tire tread condition is generally checked by visual inspection that can be easily forgotten. In this paper, we propose the intelligent tire (iTire) system that consists of an acceleration sensor, a wireless signal transmission unit and a tread classifier. In addition, we also presents classification algorithm that transforms the acceleration signal into the frequency domain and extracts the features of several frequency bands as inputs to an artificial neural network. The artificial neural network for classifying tire wear was designed with an Multiple Layer Perceptron (MLP) model. Experiments showed that tread wear classification accuracy was over 80%.

• Journal of Korea Multimedia Society
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• v.18 no.12
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• pp.1519-1527
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• 2015

TFT-LCD automatic defect inspection system for detecting defects in place of the visual tester does pre-processing, candidate defect pixel detection, and recognition and classification through a blob analysis. An over-detection result of defects acts as an undue burden of blob analysis for recognition and classification. In this paper, we propose defect detection method based on the histogram distribution modeling of TFT-LCD image to minimize over-detection of candidate defective pixels. Primary defect candidate pixels are detected estimating the skewness of the luminance distribution histogram of the background pixels. Based on the detected defect pixels, the defective pixels other than noise pixels are detected using the distribution histogram model of the local area. Experimental results confirm that the proposed method shows an excellent defect detection result on the image containing the various types of defects and the reduction of the degree of over-detection as well.

• The Korean Journal of Applied Statistics
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• v.22 no.3
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• pp.569-584
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• 2009

Edge detection in images has been widely used in image processing system and computer vision. Morphological edge detection has used structuring elements with fixed shapes. This paper presents morphological operators with non-fixed shape kernels, or amoebas, which take into account the image contour variations to adapt their shape. Experimental results are analyzed in both qualitative analysis through visual inspection and quantitative analysis with PFOM and ROC curves. The Experiments demonstrate that these novel operators outperform classical morphological operations with a fixed, space-invariant structuring elements for edge detection applications.

• Journal of Sensor Science and Technology
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• v.23 no.2
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• pp.99-104
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• 2014

Sensor arrays based on chemical sensors produce multidimensional patterns of data that may be used discriminate between different chemicals. For the human observer, visualization of multidimensional data is difficult, since the eye and brain process visual information in two or three dimensions. To devise a simple means of data inspection from the response of sensor arrays, PCA (Principal Component Analysis) or Sammon's nonlinear mapping technique can be applied. The PCA, which is a well-known statistical method and widely used in data analysis, has disadvantages including data distortion and the axes for plotting the dimensionally reduced data have no physical meaning in terms of how different one cluster is from another. In this paper, we have investigated two techniques and proposed a combination technique of PCA and nonlinear Sammom mapping for visualization of multidimensional patterns to two dimensions using data sets from odor sensing system. We conclude the combination technique has shown more advantages comparing with the PCA and Sammon nonlinear technique individually.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.11
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• pp.705-710
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• 2011

Fault detection has to be proceeded by steady state filtering to get rid of transient effect associated with thermal capacity. Coefficient of variance (COV), ratio of standard deviation devided by moving average, was employed as steady-state filter. Engine speed and refrigerant pressures were selected as parameters representing system dynamics. The filtered values were registered as members of steady-state DB. They were found to show good functional relationship with ambient temperature. The relationship was fitted with a second order polynomial and the distribution bounds of the data around the fitted curve were expressed by visual inspection because of varying average and random data interval. Fault data were compared with the steady-state data obtained during normal operation. The fault data were easily isolated from the fault-free one. To make such isolation reliable, tests to construct good DB should be designed in a systematic way.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.567-570
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• 2003

Fractal mathematics is being highlighted as a research method for classification of image. But the application of Fractal dimension(FD) has been required the complicated calculation method because of its complex repetition progressing. In this paper, it has been developed the new approach method to express the Fractal Dimension(FD) for aging level calculation and estimation system of outside insulator using special image processing algorithm. As a result after FD testing, the recognized aging estimation of FD has a very characteristics compared to the conventional visual inspection.

• Journal of the Korean institute of surface engineering
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• v.51 no.5
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• pp.316-324
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• 2018

Harsh seawater environment is subdivided into marine atmosphere, splash zone, tidal zone, submerged zone and bottom of sea depending on the exposed part. Since corrosion rate depends on the conditions of the exposed parts, proper protection and maintenance for each parts are essential for long-term use of steel structures in seawater environment. For steel structures which were installed in Shiwha Lake, a special maintenance system is required to guarantee its long-term durability and safety. As the tidal power plant has recently been operated, the salinity has risen due to the rapid influx of seawater upstream into Sihwa Lake and the corrosion tendency of the structure is variable according to the water level fluctuation. In this study, corrosion properties of steel structures under water level fluctuation was evaluated by corrosion rate measurement, visual inspection and natural potential measurement and their durability and life management were discussed in view of the effect of variation in of seawater level fluctuations in Shihwa Lake.