• Journal of Korea Multimedia Society
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• v.14 no.2
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• pp.238-248
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• 2011

Various services through mobile have been expanding since the development of the Smartphones. People freely communicate, remake and redistribute the information through Wi-Fi. People's freedom can cause lots of problems. There are application licenses of various types in the Android platform. However, problems about redistribution are indiscriminately distributed what can't be disentangled commercial and noncommercial use. To solve these problems, an application program has to go through procedures of license check in the Android platform. This method has two problems. One, an exact license authentication is impossible in the place where Wi-Fi does not work. The other thing, this license information is stored directly into the Smartphone. Therefore, attacks are possible about the stored license information, To solve these problems, we designed and implemented the file structure for storing the license information into USIM. We can store and authenticate them. Thus, we propose above the authentication method that can be authenticated the license authentication safely in on or off-line.

• Journal of the Korea Safety Management & Science
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• v.17 no.2
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• pp.117-127
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• 2015

This study investigated the smoke blocking and control systems for the safety of residents evacuation and for the prevention of smoke spread through the central corridor in the event of central corridor type of intelligent building fire. We offered additional ways of utilizing smoke ventilators and intake ventilation equipment and utilized CFD-based fire simulation program(FDS Ver.5.5.3) in order to analyze the effect. As a result, many differences in the smoke block effect, depending on the application of smoke ventilator and location of installation, was found. In addition, the result was found that larger effect was showed not in the case of application of smoke ventilator in central corridor only but application in fire room. The reason is that the smoke leakage is blocked primarily as air is flowed in the fire room through open door by operation of intake smoke ventilator in the public corridor and secondarily, the smoke leakage to the public corridor could be blocked as fire and smoke were released to the opened smoke ventilator continuously. Especially, the effect was maximized through complex interactions by applying smoke ventilator and intake ventilation equipment in corridor together rather than applying smoke ventilator and intake ventilation equipment independently. The proposed measure through this study shall be considered from architectural plan as one of ways for blocking from smoke spread to the central corridor in the central corridor type of intelligent building. In addition, flaws on regulation shall be established and supplemented.

• Journal of Radiation Protection and Research
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• v.34 no.1
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• pp.25-30
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• 2009

Micro-columnar CsI(Tl) is the most popular scintillator material which is used for many indirect digital X-ray imaging detectors. The light scattering at the surface of micro-columnar CsI(Tl) scintillator was studied to find the correlation between the surface roughness and the resultant image resolution of indirect X-ray imaging detectors. Using a commercially available optical simulation program, Light Tools, MTF (Modulation Transfer Function) curves of the CsI(Tl) film thermally evaporated on glass substrate with different thickness were calculated and compared with the experimental estimation of MTF values by the edge X-ray image method and CCD camera. It was found that the standard deviation value of Gaussian scattering model which is determined by the surface roughness of micro-columns could certainly change the MTF value of image sensors. This model and calculation methodology will be beneficial to estimate the overall performance of indirect X-ray imaging system with CsI(Tl) scintillator film for optimum design depending on its application.

• Convergence Security Journal
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• v.7 no.1
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• pp.29-34
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• 2007

Recently, the distribution and using of the digital multimedia contents are easy by developing the internet application program and related technology. However, the digital signal is easily duplicated and the duplicates have the same quality compare with original digital signal. To solve this problem, there is the multimedia fingerprint which is studied for the protection of copyright. Fingerprinting scheme is a technique which supports copyright protection to track redistributers of electronic information using cryptographic techniques. Only regular user can know the inserted fingerprint data in fingerprinting schemes differ from a symmetric/asymmetric scheme and the scheme guarantee an anonymous before re-contributed data. In this paper, we present a new scheme which is the detection of colluded multimedia fingerprint by neural network. This proposed scheme is consists of the anti-collusion code generation and the neural network for the error correction.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.1
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• pp.11-18
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• 2013

In order to prevent tampering and reverse engineering of executive code, this paper propose a new tamper resistant software mechanism. This paper presents a cryptographic MAC function and a relationship which has its security level derived by the importance of code block instead of by merely getting the encryption and decryption key from the previous block. In this paper, we propose a cryptographic MAC function which generates a dynamic MAC function key instead of the hash function as written in many other papers. In addition, we also propose a relationships having high, medium and low security levels. If any block is determined to have a high security level then that block will be encrypted by the key generated by the related medium security level block. The low security block will be untouched due to efficiency considerations. The MAC function having this dynamic key and block relationship will make analyzing executive code more difficult.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.4 s.310
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• pp.80-87
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• 2006

Recently, the distribution and using of the digital multimedia contents are easy by developing the internet application program and related technology. However, the digital signal is easily duplicated and the duplicates have the same quality compare with original digital signal. To solve this problem, there is the multimedia fingerprint which is studied for the protection of copyright. Fingerprinting scheme is a techniques which supports copyright protection to track redistributors of electronic inform on using cryptographic techniques. Only regular user can know the inserted fingerprint data in fingerprinting schemes differ from a symmetric/asymmetric scheme and the scheme guarantee an anonymous before recontributed data. In this paper, we present a new scheme which is the detection of colluded multimedia fingerprint by neural network. This proposed scheme is consists of the anti-collusion code generation and the neural network for the error correction. Anti-collusion code based on BIBD(Balanced Incomplete Block Design) was made 100% collusion code detection rate about the average linear collusion attack, and the hopfield neural network using (n,k)code designing for the error bits correction confirmed that can correct error within 2bits.

• Corrosion Science and Technology
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• v.7 no.1
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• pp.45-49
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• 2008

The cyclic polarisation technique was applied to determine the corrosion, primary-passivation, transpassive, and protection potential of AISI 316L stainless steels immersed in 3550-ppm NaCl solution containing sulfate in the content up to 3000 ppm. The solutions were kept constant at $27^{\circ}C$ and saturated by laboratory air. The solution pH was varied from 3 to 11. Each type of potentials was plotted in function of pH and linked as lines to determine the different zones in the constructed potential-pH diagram. The predominant regimes of the immunity, general corrosion, perfect passivation, imperfect passivation, and pitting corrosion were determined based on those lines of potentials. Comparing to the potential-pH diagram of specimens immersed in the aerated and deaerated 3550-ppm NaCl solutions, the addition of 3000-ppm $Na_2SO_4$ to these solutions increased the overall, perfect and imperfect, passivation regime by shifting the transpassive-potential line to the noble direction. However, it also widened the imperfect passivation area. The addition of $Na_2SO_4$ did not significantly affect the corrosion potential. It was found that the dissolved oxygen tends to negatively shift the transpassive-potential and protection-potential lines at all studied pH. The considerable effect of dissolved oxygen on corrosion and primary-passivation potentials could not be observed.

• Fire Science and Engineering
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• v.34 no.4
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• pp.69-77
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• 2020

With the recent enlargement and complication of buildings, damage caused by the incidents of fires breaking out are escalating. Consequently, the use of sprinkler facilities is increasing among water-based fire extinguishing systems. Piping materials used in fire prevention systems include carbon steel (for general or pressure pipeline), CPVC, copper, and stainless-steel. Among these, the steel and CPVC pipes, which are commonly employed in fire prevention, were considered for testing the reliability of the water-based systems. This analysis was performed using the PIPENET software to perform hydraulic calculations in order to examine the flow and pressure at the terminal head when the corrosion coefficient was applied; this coefficient was applied considering the aging of pipes. Assuming a uniform pipe diameter in the steel pipes, the rated flow in the pump installed on the first floor of the basement was reduced by over 10% after 20 years had passed (C value of 90); moreover, the reduction in pressure and flow at its terminal head exceeded 30% and 16.5%, respectively. The results indicate that it is difficult to ensure the reliability of these fire prevention facilities. Furthermore, according to our estimation, considering 30 years had passed (C value of 80), the rated flow of the pump was reduced by over 15%, and the corresponding reduction in pressure and flow at its terminal head exceeded 42% and 24%, respectively.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.3
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• pp.251-257
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• 2013

In this study, ultraviolet protection factor (Sun Protection Factor, SPF) was investigated to provide basic data for subject safety and research of ultraviolet (UV) irradiation test in the future. Trial subjects (395 people) of skin type I, II, and III were evaluated according to skin type standard table. After measuring the skin color using a colorimeter, ITA (Individual Typology Angle) value was calculated. Subjects with 28 and above ITA value were positioned comfortably to be UV irradiated for 60 s and erythema was evaluated 24 hours after application. MED (Minimal Erythema Dose) was investigated where the minimal amount of erythema existed among UVB irradiated area. Statistical analysis was investigated using Statistical Package the Social Sciences program. As a result, the darker skin color results in the higher MED value since the higher skin type number results increased MED value and female has higher MED value than male since female has darker skin type than male. There was no relation between MED difference by ages in all different ages. However, it is hard to draw a conclusion as above since the number of subjects were not sufficient to support statistical significance for MED values by different ages. However, MED values by skin types obtained through this study can be used as a standard when MED value is expected to evaluate efficacy of sunscreen product and as basic data for further safety of clinical researches.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.341-345
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• 2019

Ethyl formate (EF) is a rapid kill, environmentally safe, and low mammalian toxicity fumigant, registered to disinfest quarantine insect pests from imported agricultural products. A new concept for controlling insect pests of agricultural crops was tested in a fumigation chamber with EF. Control efficacy of and phyto-toxicity due to EF fumigation were evaluated against four pests (Thrips palmi, Bemisia tabaci, Myzus persicae, and Tetranychus urticae) and on seedlings of four fruit vegetables (FVs; yellow melon, cucumber, tomato, and pepper). Ethyl formate fumigation at a dose of 1.5 g m^-3 for 12 h produced >93.3% mortality in T. palmi, B. tabaci, and M. persicae. However, T. urticae was tolerant to fumigation, showing only 20% mortality at 2.0 g m^-3. In terms of concentration × time (CT) products, at least 8.9 g·h m^-3 CT at 20 ± 1.5℃ was needed to achieve > 90% mortality against the three susceptible insect pests. Fumigation at 1.5 g m^-3 for 12 h caused no phyto-toxicity to any of the four FV seedlings. Ethyl formate application, as a new disinfestation method in greenhouses, could be an alternative to reduce the use of conventional insecticides. However, further studies are needed to determine the efficacy of this method at different pest developmental stages and in different greenhouse environments. Additionally, research is needed to elucidate the phyto-toxicity of EF application at different growing stages of a wide variety of crops.