• Journal of Digital Convergence
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• v.14 no.11
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• pp.449-457
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• 2016

At this study, we select five colorful and high-acid fruits: grape, lemon, orange, grapefruit and kiwi, and we made a composite resin specimen and dipped into fruit juice in order to figure out influence that affects on surface corrosion and coloring. We dipped resin specimen into fruit juice by three-day and seven-day interval at $37^{\circ}C$. Control group used the resin that was not dipped into fruit juice. For surface change according to the time, it was observed by using scanning electron microscopy, and it was measured by using spectrophotometer for change of coloring degree. As a result of surface change of resin by using scanning electron microscopy, furrow size between surface particles increased, and rectangular rod-shape structure was emerged, and small prominent particles on bumps disappeared. As a result of coloring degree of resin by measuring spectrophotometer, a difference between experimental group appears with the darkest brightness in the case where it is dipped into grape extracts.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.3
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• pp.39-47
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• 2022

In this paper, we proposed a thickness measurement method of concrete slab using GPR, and the verification of the suggested algorithm was carried out through real-scale experiment. The thickness measurement algorithm developed in this study is to set the relative dielectric constant based on the unique shape of parabola, and time series data can be converted to thickness information. GPR scanning were conducted in four types of slab structure for noise reduction, including finishing mortar, autoclaved lightweight concrete, and noise damping layer. The thickness obtained by GPR was compared with Boring data, and the average error was 1.95 mm. In order to investigate the effect of finishing materials on the slab, additional three types of finishing materials were placed, and the following average error was 1.70 mm. In addition, sampling interval from device, the effect of radius on the shape of parabola, and Boring error were comprehensively discussed. Based on the experimental verification, GPR scanning and the suggested algorithm have a great potential that they can be applied to the thickness measurement of finishing mortar from concrete slab with high accuracy.

• Korean Journal of Environmental Agriculture
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• v.15 no.1
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• pp.19-24
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• 1996

To investigate the alterations of ultrastructure of leaves by acid rain, 10mm of SAR(Simulated Acid Rain, pH 2.0, 2.5, 2.7, 3.0, 6.0) were applied to 4 crops(rice, soybean, barley, and radish) at the two day interval. The symptoms of leaf damage by SAR were observed by naked eyes and SEM(Scanning Electron Microscope). The results are summarized as follow: Visible leaf injury were more serious in dicots than monocots such as rice and barley with the order of bean, radish, rice, barley. With the SAR treatment of pH 2.0, histological perturbation of trichome were developed in bean and radish. And with the SAR treatment of pH 2.5, stomata of all tested crops except rice were deshaped.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.11
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• pp.861-869
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• 2013

We consider an information system where viruses arrive according to a Poisson process with rate ${\lambda}$. The information system has two types of anti-virus operation policies including 'real-time scan' and 'batch scan.' In the real-time scan policy, a virus is assumed to be scanned immediately after its arrival. Consequently, the real-time scan policy assumes infinite number of anti-viruses. We assume that the time for scanning and curing a virus follows a general distribution. In the batch scan policy, a system manager operates an anti-virus every deterministic time interval and scan and cure all the viruses remaining in the system simultaneously. In this paper we suggest a probability model for the operation of anti-virus software. We derive a condition under which the operating policy is achieved. Some numerical examples with various cost structure are given to illustrate the results.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.8
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• pp.3-12
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• 2016

Bluetooth Low Energy (BLE) protocol has attracted attention as a promising technology for low data throughput and low energy wireless sensor networks. Fast device discovery is very important in a BLE based wireless network. It is necessary to configure the network to work with minimized energy consumption because the BLE network nodes are expected to operate a long time typically on a coin cell battery. However, since it is difficult to obtain low energy and low latency at the same time, the BLE standard introduces wide range setting of parameters related to device discovery process and let the network operators to set up parameter values for the application. Therefore, it is necessary to analyze the performance of device discovery according to the related parameter values prior to BLE network operation. In this paper we analyze the expected value and the cumulative distribution function of the number of advertisements for device discovery in the BLE network. In addition, we propose a scheme for controlling the interval between advertising events that can improve the performance of device discovery without increasing energy consumption.

• The Journal of Advanced Prosthodontics
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• v.12 no.3
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• pp.167-172
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• 2020

PURPOSE. The aim of the present study was to investigate the passive fit of metal substructure after repetitive firing processes in implant-supposed prosthesis. MATERIALS AND METHODS. Five implants (4 mm diameter and 10 mm length) were placed into the resin-based mandibular model and 1-piece of screw-retained metal substructure was produced with the direct metal laser sintering (DMSL) method using Co-Cr compound (n = 10). The distance between the marked points on the multiunit supports and the marginal end of the substructure was measured using a scanning electron microscope (SEM) at each stage (metal, opaque, dentin, and glaze). 15 measurements were taken from each prosthesis, and 150 measurements from 10 samples were obtained. In total, 600 measurements were carried out at 4 stages. One-way ANOVA test was used for statistical evaluation of the data. RESULTS. When the obtained marginal range values were examined, differences between groups were found to be statistically significant (P<.001). The lowest values were found in the metal stage (172.4 ± 76.5 ㎛) and the highest values (238.03 ± 118.92 ㎛) were determined after glaze application. When the interval values for groups are compared with pairs, the differences between metal with dentin, metal with glaze, opaque with dentin, opaque with glaze, and dentin with glaze were found to be significant (P<.05), whereas the difference between opaque with metal was found to be insignificant (P=.992). CONCLUSION. Passive fit of 1-piece designed implant-retained fixed prosthesis that is supported by multiple implants is negatively affected by repetitive firing processes.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.2
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• pp.158-165
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• 1998

This study was undertaken to observe the effects of the antineoplastic agent, 5-Fluorouracil(5 FU) on the hair in Sprague-Dawley white rats. Twenty four sprague-Dawley strain white rats, each weighing about 150-200 grams were used and divided into control and experimental groups. In the experimental group, eighteen rats were injected intraperitonially with 60 mg of 5-FU per killogram body weight with one time per two days, Six rats were injected with 0.5 cc of normal saline solution intraperitoneally as a placebo on this control group. Rats were serially sacrificed on the first, third, fifth, seventh, tenth and fourteenth day after 2 times of injection of 5-FU and saline. The hair were obtained and observed SEM. After examination and comparision of all specimens, the results of this study were as follows: 1. In the control group, the scale and cuticle of hair was observed smooth surface and equal interval 2. In the experimental group, the first day, scale change was seen from body of hair and crack was seen. from fifth day, and irregular scale and cuticle of hair was seen from 10, 14 days 3. The apperance of root of hair was not almost change From above results, 5-Fluorouracil was more effective on the hair body. The change was begun from first day and crack of scale was seen from fifth day and irregular scale and cuticle of hair was seen from 10,14 days. The.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.282-288
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• 1995

To investigate the alterations in the ultrastructure of leaves by acid rain, 10mm of SAR(Simulated Acid Rain, pH 2.0, 2.7, 3.0, 6.0) was applied to three crops(red-pepper, perilla, eggplant) at a two-day interval. The symptoms of leaf damage by SAR were observed by naked eyes and SEM(Scanning Electron Microscope), and the peroxidase activity in the leaves was measured. The results are summarized as follows : The severity of SAR damages to the crops observed by naked eye were in the decreasing order of red-pepper, perilla, and eggplant. The Symptoms were characterized by brown or white spots on the leaf surface. In the SAR treatment of pH 3.0, trichomes of all crops except for eggplant were damaged. By the SAR treatment of pH 2.7, stomata were damaged in all crops. With one time treatment of SAR, the peroxidase activity of perilla was rapidly increased.

• The Transactions of the Korea Information Processing Society
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• v.7 no.7
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• pp.2149-2160
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• 2000

Recently many efforts on the development of automatic processing system for delivery sequence sorting have been performed in ETRI, which requires the use of postal4-state bar code system to encode delivery points. The 4-state bar code called postal 4-state barcode for high speed processing that has been specifically designed for information processing of logistics and automatic processing of he mail items. The Information of 4-state bar code indicates mail data such as post code, delivery sequence number, error correction code worked, customer information, and a unique ID. This appear addresses the issue on he reduction of reading error in postal 4-state raster beam based bar code reader. The raster beam scanning features are the unequally distributed number of spots per each unit, which cause reading errors. We propose a method for reducing the bar code reading error by adjusting measured values of bar code width to its average value over each interval. The test results show that the above method reduces the average reading error rate approximately by 99.88%.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.2
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• pp.77-81
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• 2010

D&B(Drill & Blast) method in tunnel construction requires accurate and rapid measurement of the ground movement, which is essential for feedback analysis. Case study and adaptability of IT technique for tunnel survey are discussed in this paper. The application of laserscannig and existing light wave instrument method in the field of tunnel construction were reported in several advanced country including Austria and Japan. Survey for the shoulder movements by IT survey method was conducted at a subway construction site and the results were compared to the conventional method. Also, the economic aspects of laserscannig method were analyzed using measured data which were categorized by expenses, frequency, interval and period in the field of construction. Therefore IT survey solution may contribute to execute more economic and safe construction