• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.1
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• pp.71-78
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• 2009

Korea Marine Environment Management Corporation (KOEM) has waste oil facilities in 13 ports to collect and treat waste oil, bilge, etc. from ships based upon the Marine Environment Management Act of Korea and MARPOL 73/78 convention. Those facilities were designed and have been operated simply to discharge water under the level 15 ppm of oil contents. However, bad smells occurred from rotten organic matters in waste water and direct discharge of harmful substances to receiving water caused civil appeals. Therefore, KOEM tried to develop new process for treatment of oily waste water from ships, which could mitigate harmful substances, save cost, calm down civil appeals and contribute to marine environment preservation. This process consists of 3 steps to remove oil contents via gravity variation at first, $O_3$ input to contact water and organism deposition by inputting condensate deposits. Then finally upper water will be discharged, and the deposited substances in the bottom will be compressed through spinning machine to transfer to the designated contractors for treatment of wastes. This is very effective and innovative in that it could reduce 3 or 4 steps compared with existing process and mitigate not only waste oil concentration but also hard resolving materials such as colloid, ABS, phosphorus, nitrogen and bad smells. This method is expected to minimize bad smells and harmful gases, to save more than 10% of maintenance cost, and to arrange the good base for garbage treatment business dealing with waste water and bad smell.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.425-430
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• 2017

RFID is a technology that uses radio frequency to read information in tags attached to objects or people. Because it reads the information without contact when tracking the location using tags in a RFID system, there can be errors between the actual position and measured position. In this paper, three methods (the method of radiation pattern, the method of the median value, and the method using both the radiation pattern and median value) are proposed to identify the location of objects or people using the RFID technique. The location identification system based on RFID was constructed and tags were arranged in a square pattern. The real location and experimentally predicted location of an object containing a reader were compared to confirm the error. Instead of the existing papers that obtained the approximately location of a reader by calculating the center of gravity of all tags read by that reader, in this study, the predicted location was obtained by the median value and the radiation pattern. This study validated which method was the most efficient among the three methods proposed in this paper through the data of the read tags. As a result, the method of the median value had the smallest error among those assessed.

• Journal of Korea Multimedia Society
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• v.13 no.9
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• pp.1337-1347
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• 2010

Fingerprint recognition is a biometric technology to identify individual by using fingerprint features such ridges and valleys. Most fingerprint systems perform the recognition based on minutiae points after acquiring a fingerprint image from contact type sensor. They have an advantage of acquiring a clear image of uniform size by touching finger on the sensor. However, they have the problems of the image quality can be reduced in case of severely dry or wet finger due to the variations of touching pressure and latent fingerprint on the sensor. To solve these problems, the contactless capturing devices for a fingerprint image was introduced in previous works. However, the accuracy of detecting minutiae points and recognition performance are reduced due to the degradation of image quality by the illumination variation. So, this paper proposes a new LDP-based fingerprint recognition method. It can effectively extract fingerprint patterns of iterative ridges and valleys. After producing histograms of the binary codes which are extracted by the LDP method, chi square distance between the enrolled and input feature histograms is calculated. The calculated chi square distance is used as the score of fingerprint recognition. As the experimental results, the EER of the proposed approach is reduced by 0.521% in comparison with that of the previous LBP-based fingerprint recognition approach.

• Tunnel and Underground Space
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• v.22 no.1
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• pp.69-76
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• 2012

Theoretical backgrounds on the experimental methods of explosive welding, explosive forming and shock consolidation of powders are introduced. Explosive welding experiments of titanium (Ti) and stainless steel (SUS 304) plate were carried out. It was revealed that a series of waves of metal jet are generated in the contact surface between both materials; and that the optimal collision velocity and collision angle is about 2,100~2,800 m/s and $15{\sim}20^{\circ}$, respectively. Also, explosive forming experiments of Al plate were performed and compared to a conventional press forming method. The results confirmed that the shock-loaded Al plate has a larger curvature deformation than those made using conventional press forming. For shock consolidation of powders, the propagation behaviors of a detonation wave and underwater shock wave generated by explosion of an explosive are investigated by means of numerical calculation. The results revealed that the generation and convergence of reflected waves occur at the wall and center position of water column, and also the peak pressure of the converged reflected waves was 20 GPa which exceeds the detonation pressure. As results from the consolidation experiments of metal/ceramic powders ($Fe_{11.2}La_2O_3Co_{0.7}Si_{1.1}$), shock-consolidated $Fe_{11.2}La_2O_3Co_{0.7}Si_{1.1}$ bulk without cracks was successfully obtained by adapting the suggested water container and strong bonding between powder particles was confirmed through microscopic observations.

• Korean Security Journal
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• no.9
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• pp.201-235
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• 2005

This study is designed to contribute for development of Private Security Business by fact-finding in instruction and training of private security guard serviced in this realm and domestic and foreign guard service and modeling effective and rational instruction and training program based on drawn problem. For this study, basically I collected and analyzed documents, theses, and papers of the inside and outside of the country. For practical use of data, I used materials of private security related institutes and police agency. And for private security educating training programs of the inside and outside of the country, I collected materials on internet, and with the help of police agency and interpol. For korean private security company's educating training programs, I made a study with the interview of private security company's businessmen. This study's conclusion is as follows. In a domestic private security enterprise, when set theory instruction minimize instruction and training program and must set up instruction and training program as practical affairs center enemy instruction, and theory instruction must be composed for instruction me that it is connected to practical affairs instruction too. The instruction course of private security guard instruction and training program composed with a security outline, a security plan, an information-gathering, civilian expenses, a security way, terror and terrorism, a related law, security trial, electronic security, a security analysis technique, company introduction, instruction and training program about a professional tube with theory instruction. Practical affairs instruction composed with the selection and a preventive security, close contact attendance security, vehicle security, security driving the security martial arts and self-protection liquor, first aid, security equipment, a gun and shooting, a security protocol, customer satisfaction, facilities security and expenses, a fire fighting instruction, teamwork training, explosive and a dangerous substance, physical strength, a documentation practical affairs, service, instruction and training program about foreigh language instruction.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.260-265
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• 2002

Microbiologically influenced Corrosion (MIC) is one of the most deleterious effects of metal microbe interactions. When a fresh metal surface comes in contact with a non-sterile fluid, biofilm formation is ensued. This might result in the initiation of corrosion. The sites and materials where MIC is implicated are versatile. Industries such as shipping, power generation, chemical etc are reported to be affected. The rapid and unexpected failure of AISI type 304 stainless steel was investigated in the laboratory by simulation studies for a period of 4 months. Slime and water samples from the failure site were screened for corrosion causing bacteria. Both aerobic and anaerobic nora were enumerated and identified using PCR techniques. Pseudomonas sp. and Bacillus sp. were the most common aerobic bacteria isolated from the water and slime samples, whilst sulfate reducing bacteria (SRB) were the major anaerobic bacteria. The aerobic bacteria were used for the corrosion experiments in the laboratory. Coupon exposure studies were conducted using a very dilute (0.1%V/V) nutrient broth medium. The coupons after retrieval were observed under a Scanning Electron Microscope (SEM) for the presence of MIC pits. Compared to sterile controls, metal coupons exposed to Pseudomonas sp and Bacillus sp. showed the initiation of severe pitting corrosion. However, amongst these two strains, Psudomonas sp. caused pits in a very short span of 14 days. Towards the end of the experiment, severe pitting was observed in both the cases. The detailed observation of pits showed they vary both in number and shapes. Whilst the coupons exposed to Bacillus sp. showed widely spread scales like pits, those exposed to Pseudomonas sp. showed smaller and circular pits, which had grown in number and size by the end of the experiment. From these results it is inferred that the rapid and unexpected failure of 304 SS might be due to MIC. Pseudonwnas sp. could be considered as the major responsible bacteria that could initiate pits in the metallic structures. As the appearance of pits was different in both the tested strains, it was thought that the mechanisms of pit formation are different. Experiments on these lines are being continued.

• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.450-459
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• 2014

Crushed pinewood and oakwood were studied as an adsorbent for Pb(II) removal from aqueous solution. Batch adsorption experiments were carried out to describe the effects of contact time, initial Pb(II) concentration, pH, competing cations, and adsorbent dosage on the Pb(II) adsorption process. Kinetic studies revealed that the Pb(II) adsorption process for pinewood and oakwood followed both pseudo first and pseudo second order model. The Fruendlich model best described equilibrium adsorption data with correlation coefficients ($R^2$) of 0.956 and 0.950 for pinewood and oakwood. The maximum adsorption capacity of Pb(II) onto pinewood and oakwood was found to be 16.853 and 27.989 mg/g, respectively. The Pb(II) adsorption onto both pinewood and oakwood was increased as pH increased in the pH range 3-9. The presence of cations such as $Na^+$, $Ca^{2+}$, and $Al^{3+}$ decreased Pb(II) adsorption. The Pb(II) removal was greater in seawater than deionized water, resulting from the presence of $CO{_3}^{2-}$ and $OH^-$ ions in seawater. This study showed that pinewood and oakwood have a potential application in the remediation of Pb(II) contaminated water.

• Journal of the Korean Vacuum Society
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• v.21 no.2
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• pp.78-85
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• 2012

In order to improve the adhesion between poly-monochloro-para-xylylene (Parylene-C) film and Aluminum thin film, the surface of Parylene-C film was irradiated by ${O_2}^+$ and $Ar^+$ ion beam generated by duoplamatron ion source. The ion dose of $Ar^+$ and ${O_2}^+$ was changed from $5{\times}10^{14}$ to $1{\times}10^{17}/cm^2$ and the ion beam energy was 1 kV. Contact angles of water on Parylene-C modified by $Ar^+$ and ${O_2}^+$ ion irradiation decreased from $78^{\circ}$ to around $17^{\circ}$, and $9^{\circ}$, respectively. X-ray photoelectron spectroscopy analysis shows that the hydrophilic groups were formed on the surface of Parylene-C by chemical reaction between the unstable chains induced by the ion irradiation and oxygen ions or residual oxygen gas. The hydrophilic groups were identified as C-O bond, C=O bond and (C=O)-O bond. The cross cut tape test which was applied to characterize the adhesion between Al thin film and Parylene-C film modified by ${O_2}^+$ ions irradiation shows that the adhesion strength was improved as increasing ion dose.

• The korean journal of orthodontics
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• v.37 no.5
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• pp.364-375
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• 2007

The purpose of this study was to compare arch dimensions and frequency distribution of arch forms between Korean and Japanese Class I, II, and III malocclusion groups. Methods: The sample consisted of 368 Korean cases (114 Class I, 119 Class II, and 135 Class III malocclusion) and 160 Japanese cases (60 Class I, 50 Class II, and 50 Class III malocclusion). The most facial portion of 13 proximal contact areas was digitized from photocopied images of the mandibular dental arches. Clinical bracket slot points were calculated for each tooth based on mandibular tooth thickness data. Four linear and two proportional measurements were taken. Measurements are statistically analyzed in each malocclusion group. The dental arches were classified into square, ovoid, and tapered forms to determine and compare the frequency distributions between the two ethnic groups. Results: The findings of this study showed that Japanese females in Class I and II groups had a statistically significant narrower mandibular dental arch width compared with the Japanese males, Korean males and Korean females. But in the Class III group, there was no significant difference in the mandibular dental arch size according to the two ethnic groups and genders. Conclusions: The majority of Koreans and Japanese in all the malocclusion groups exhibited square and ovoid arch forms. The most frequent arch forms found in Koreans was square but ovoid for Japanese.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.1
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• pp.31-36
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• 2013

Acetylated Cellulose Ether (ACE), cellulose-based amphiphilic polymer with hydrophilic and hydrophobic, was synthesized and investigated in terms of its solubility and wettability for organic solvents and water. Acetyl group was substituted to the cellulose ether in a hydrophilic polymer by esterification. As a result of FT-IR, the peak corresponding to the hydroxyl group decreased and carboxyl acid peak increased with increasing reaction time and temperature, which signified the increase in the degree of acetylation of the ACE. There were similar thermal decomposition behaviors before and after esterification reaction until $800^{\circ}C$ so that the reaction occurred without significant structural changes of cellulose backbones. The solubility parameter of the ACE had a range of 18.5~26.4, and its viscosity and turbidity were controlled according to the solubility parameter of organic solvents. The ACE showed the hydrophilicity because the contact angle of the ACE was higher than the cellulose ether. These results confirmed that the ACE had the hydrophobicity and hydrophilicity due to the ether which was glucosidic bonding between the glucose units and un-reacted hydroxyl functional groups in the ACE.