• Explosives and Blasting
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• v.31 no.2
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• pp.14-24
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• 2013

The most effective way of the rock removing works in the downtown area is to removing rocks by splitting the rock by blasting with small amount of explosives in the hole. However environmental factors not only limit the applications but also increase the forbidden area. As this is a distributed multi-stage blasting method and to reduce vibration by applying the optimized precisioncontrol-blasting method, it is applicable in all situations. The process is to fix the stemming-help plastic sheet to the hole entrance when stemming explosives and insert detonator and explosive primer with same delay time, two or three sets. This method is more efficient in the downtown area where claims and dispute from vibration are expected. This method is easily usable by designing blast pattern even in the area where delay time blasting is difficult after multi-stage explosive stemming due to short length of blast hole (1.2~3.0m) and there is no detonator wire shortage or dead-pressure.

• Journal of Digital Contents Society
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• v.19 no.9
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• pp.1787-1793
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• 2018

Shadow is a common phenomenon observed in natural scenes, but it has a negative influence on image analysis such as object recognition, feature detection and scene analysis. Therefore, the process of detecting and removing shadows included in digital images must be considered as a pre-processing process of image analysis. In this paper, the existing methods for acquiring 1D invariant images, one of the feature elements for detecting and removing shadows contained in a single natural image, are described, and a method for obtaining 1D invariant images based on linear regression has been proposed. The proposed method calculates the log of the band-ratio between each channel of the RGB color image, and obtains the grayscale image line by linear regression. The final 1D invariant images were obtained by projecting the log image of the band-ratio onto the estimated grayscale image line. Experimental results show that the proposed method has lower computational complexity than the existing projection method using entropy minimization, and shadow detection and removal based on 1D invariant images are performed effectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.162-171
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• 2017

Low frequency noise components causes the baseline drift in the ECG signals. In this paper, a morphological operation and smoothing spline technique are used for ECG signal processing in order to accomplish baseline correction. Removing the baseline drift from ECG signal using morphology operation, the feature of original signal may be distorted. To resolve this distortion problem, we applied a smoothing spline operation after morphology operation. In order to compare with existing morphology operation method for baseline correction, we apply proposed method to ECG data in MIT/BIH database. Compared to other existing method, our proposed method achieved low data distortion on the original signal.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.1
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• pp.38-45
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• 2007

We propose a preprocessing method for removing floating particles from underwater images based on an analysis of the image features. We compared baseline JPEG and wavelet codec methods to determine the method best suited for underwater images. The proposed preprocessing method enhanced the compression ratio and resolution, and provided an efficient means of compressing the images. The wavelet codec method yielded better compression ratios and image resolutions. The results suggest that the wavelet codec method linked with the proposed preprocess method provides an efficient codec processor and transmission system for underwater images that are used for searches and transmitted via ultrasonic communications.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.8-16
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• 2022

In this paper, we propose a method of reconstructing the file system to obtain digital forensics information from the APFS file system when meta information that can know the structure of the file system is deleted due to partial damage to the disk. This method is to reconstruct the tree structure of the file system by only retrieving the B-tree node where file/directory information is stored. This method is not a method of constructing nodes based on structural information such as Container Superblock (NXSB) and Volume Checkpoint Superblock (APSB), and B-tree root and leaf node information. The entire disk cluster is traversed to find scattered B-tree leaf nodes and to gather all the information in the file system to build information. It is a method of reconstructing a tree structure of a file/directory based on refined essential data by removing duplicate data. We demonstrate that the proposed method is valid through the results of applying the proposed method by generating numbers of user files and directories.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2474-2479
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• 2011

As society has developed rapidly toward a highly advanced digital information age, a multimedia communication service for acquisition, transmission and storage of image data as well as voice has being commercialized. However, image data is always corrupted by various noises during image processing, so researches for removing noises have been continued until now. In this paper, in order to remove impulse noise we proposed modified adaptive switching median filter that consists of two stages: noise detection and noise removal. Proposed algorithm only processes noise pixels and these noise pixels are replaced by filter output, so proposed algorithm performs well not only removes noise but also preserves edge information. Also we compare existing methods using PSNR(peak signal to noise ratio) as the standard of judgement of improvement effect and choose conventional algorithms to compare with our proposed method.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.234-240
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• 2013

PURPOSE. This study evaluated the effectiveness of various methods for removing provisional cement from implant abutments, and what effect these methods have on the retention of prosthesis during the definitive cementation. MATERIALS AND METHODS. Forty implant fixture analogues and abutments were embedded in resin blocks. Forty cast crowns were fabricated and divided into 4 groups each containing 10 implants. Group A was cemented directly with the definitive cement (Cem-Implant). The remainder were cemented with provisional cement (Temp-Bond NE), and classified according to the method for cleaning the abutments. Group B used a plastic curette and wet gauze, Group C used a rubber cup and pumice, and Group D used an airborne particle abrasion technique. The abutments were observed using a stereomicroscope after removing the provisional cement. The tensile bond strength was measured after the definitive cementation. Statistical analysis was performed using one-way analysis of variance test (${\alpha}$=.05). RESULTS. Group B clearly showed provisional cement remaining, whereas the other groups showed almost no cement. Groups A and B showed a relatively smooth surface. More roughness was observed in Group C, and apparent roughness was noted in Group D. The tensile bond strength tests revealed Group D to have significantly the highest tensile bond strength followed in order by Groups C, A and B. CONCLUSION. A plastic curette and wet gauze alone cannot effectively remove the residual provisional cement on the abutment. The definitive retention increased when the abutments were treated with rubber cup/pumice or airborne particle abraded to remove the provisional cement.

• Fashion & Textile Research Journal
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• v.17 no.6
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• pp.988-995
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• 2015

Gaps between the upper edges of brassiere mold cups and the breasts are one of the most serious issues in realizing comfort wearing of commercial brassieres for small-breasted women. The surplus ease amounts causing the fit problem were measured from 3D wearing images of the small-breasted women's brassieres. The effect after the removing the surplus ease amounts from the upper edge of mold cup was approved by subjective wearing evaluation. Since the volume distribution of mold cup can also affect the wearing sensation of brassiere, the subjective wearing sensation was compared for two brassieres of different volume distributions, V_L, of which volume was concentrated at the lower cup, and V_C, which has the thickest part at the nipple. As the results, the suitable sensation for cup volume and the natural wearing silhouette could be accomplished by removing the surplus ease amounts from the upper edge of mold cup to reduce the gaps between brassieres and the breasts, which could be accomplished through an approach reducing the volume near the upper edge of mold brassiere cup and making the volume concentrated at the lower cup. These works provide a useful information on the design of the brassiere mold cups for small-breasted women. Moreover, modeling methods of 3D scan data and 3D printing technique for making more accurate mold cases used in this research can be helpful to develop and evaluate clothing products in future.

• Journal of Oral Medicine and Pain
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• v.18 no.1
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• pp.97-105
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• 1993

In order to evaluate the effectiveness of tooth brushing, mouth gargling and gum chewing in reducing halitosis, 84 individuals ranging in age from 22 59 28 years old were examined. These individuals had no gross oral abnormalities, other than mild gingival inflammation, dental caries, nasopharyngeal disorder, or systemic diseases that were associated with halitosis. They were divided into a tooth brushing group, a mouth garging group, a gum chewing group and a control group that did not use any halitosis removing method. Each of the groups included 21 persons, B.B. Checker (Tokuyama Soda Col, LTDl, Japan) was used to measure the concentrations of intraoral volatile methyl mercaptan of each group. The concentrations of intraoral volatile methyl mercaptan were measured before and after lunch, and after removing halitosis by toothe brushing, mouth gargling and gum chewing. The obtained results were as follows : 1. The average concentration of intraoral volatile methyl mercaptan before lunch was 1.79ppm and after lunch it was 2.02ppm, an increase of 12.9%. 2. In the tooth brushing group the average concentration of intraoral volatile methyl mercaptan was 0.61ppm, in the mouth gargling group it was 1.15ppm, in the gum chewing group it was 1.64ppm and in the control group it was 1.92ppm. It decreased 69.5% in the tooth brushing group, 43.8% in the mouth gargling group, 18.4% in the gum chewing group and 5.4% in the control grop (p<0.05). 3. There were significant differences between the tooth brushing and control group, tooth brushing and gum chewing group and between mouth gargling and control group in concentrations of intraoral volatile methyl mercaptan after using the halitosis removing methods (p<0.05). According to the above results, tooth brushig and mouth gargling are effective ways to reduce halitosis.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.868-874
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• 2008

The Ni based adsorbent was prepared by co-precipitation method and its performance for removing carbon monoxide was investigated. Here, silica, aluminium silicate and ${\gamma}$-alumina were used for carriers of catalyst. $Ni(NO_3)_2{\cdot}6H_2O$ and $Ni(CH_3COO)_2{\cdot}4H_2O$ were utilized for Ni precursors. Precipitants were urea and citric acid. After precipitation of Ni salt on the carrier and following reduction using $H_2$ gas, adsorbent was prepared and its performance was analyzed based on EDS, TPR and XRD experiments. In accordance with change of precipitation agents, Ni salts on carrier, carriers and reduction condition. Adsorbent performance for removing carbon monoxide was investigated. The adsorbent with 54.8 wt% Ni prepared using urea precipitant under reduction condition at $500^{\circ}C$ for 3 h exhibited the best CO removal performance.