• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.469-478
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• 2019

Car-sharing services have been settled on as a new type of public transportation owing to their enhanced convenience, expanded awareness of practical consumption patterns, the inspiration for environmental conscientiousness, and the diffusion of smart phones following the economic crisis. With development of the market, many people have started using such services. However, security is still an issue. Damage is expected since IDs and passwords are required for log-in when renting and controlling the vehicles. The protocol suggested in this study uses bio-information, providing an optimized service, and convenient (but strong) authentication with various service-provider clouds registering car big data about users through brokers. If using the techniques suggested here, it is feasible to reduce the exposure of the bio-information, and to receive service from multiple service-provider clouds through one particular broker. In addition, the proposed protocol reduces public key operations and session key storage by 20% on mobile devices, compared to existing car-sharing platforms, and because it provides convenient, but strong, authentication (and therefore constitutes a secure channel), it is possible to proceed with secure communications. It is anticipated that the techniques suggested in this study will enhance secure communications and user convenience in the future car-sharing-service cloud environment.

• Journal of KIISE:Information Networking
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• v.35 no.4
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• pp.345-354
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• 2008

Recently, small-scale mobile network which is composed of many mobile devices in a man becomes popular. Also, Examples of large-scale mobile network can be thought access networks deployed on public transportation such as ships, trains and buses. To provide seamless mobility for mobile nodes in this mobile network, binding update messages must be exchanged frequently. However, it incurs network overhead increasingly and decreases energy efficiency of mobile router. If we try to reduce the number of the messages to cope with the problem, it may happen the security -related problems conversely Thus, mobile router needs a effective algorithm to update location information with low cost and to cover security problems. In this paper, mobility management scheme based on mobile router's mobility pattern is proposed. Whenever each mobile router leaves a visiting network, it records related information as moving log. And then it periodically computes mean resident time for all visited network, and saves them in the profile. If each mobile router moves into the visited network hereafter, the number of binding update messages can be reduced since current resident time may be expected based on the profile. At this time, of course, security problems can happen. The problems, however, are solved using key credit, which just sends some keys once. Through extensive experiments, bandwidth usages are measured to compare binding update messages in proposed scheme with that in existing scheme. From the results, we can reduce about 65% of mobility-management-related messages especially when mobile router stays more than 50 minutes in a network. Namely, the proposed scheme improves network usage and energy usage of mobile router by decreasing the number of messages and authorization procedure.

• Food Science and Preservation
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• v.23 no.4
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• pp.471-478
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• 2016

For the distribution of fresh produce, the thermoelectric cooling system combined with thermo electric materials (TEM) and phase change material (PCM) was studied. The PCM used this study was produced by in-situ polymerization technology which referred microencapsulation of hydrocarbon (n-tetradecane and n-hexadecane). In this study, quality characteristics of bell peppers in thermoelectric cooling system combined with TEM and PCM were analyzed and control was placed in an EPS (expanded polystyrene) box. As a result of quality characteristics analysis, weight of bell peppers decreased and moisture content of bell peppers was 90.96~94.43% during storage. Vitamin C content of bell pepper decreased during storage and reduction ratio of control was higher than that of BPT-5 treatment(bell pepper in thermoelectric cooling system with PCM which is kept the temperature at $5^{\circ}C$). The result of color value, on 21 day, ${\Delta}E$ value of BPT-5 treatment was 5.05 while that of control was 41.8. On 21 day, total bacteria count of BPT-5 treated bell pepper shown less than that of control. In conclusion, it suggested that the thermoelectric cooling system combined with PCM improved quality of fresh produce during transportation and storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.10
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• pp.1533-1538
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• 2013

The objective of this study is to select an effective microbial strain to enhance the sensory qualities and functionalities of fermented ginseng soymilk. For this purpose, soybean were ground with water extracts of ginseng and fermented with five Lactobacillus strains. All strains grew well in ginseng soymilk, and viable cell counts reached greater than 8 log CFU/mL after 18 h of fermentation. The contents of total ginsenosides were higher in soymilk fermented with L. casei ATCC 393 than those in the other strains. The sensory qualities of the fermented soymilk were observed to increase with the intensity of sourness and showed the best sensory acceptability of soymilk fermented with L. kefir ATCC 35411. Moreover, the antioxidant activities, superoxide and hydroxyl radical scavenging activities were significantly enhanced by 2~4 and 4~5 times, respectively, compared to the non-fermented soymilk. In particular, the antioxidant activities of the fermented soymilk by L. kefir ATCC 35411 were the highest among the samples. This result suggests that soymilk fermented by L. kefir ATCC 35411 allowed obtaining a soymilk with enhanced sensory quality and antioxidant activity was able to contribute to the health benefit.

• Atmosphere
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• v.18 no.1
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• pp.25-32
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• 2008

Log normalized volume size distribution (dV/dlog$D_p$) with 52 size ranges from 0.5 to $20.0{\mu}m$ was measured for the cases of high $PM_{10}$ mass concentration (> $200{\mu}gm^{-3}$) using the Aerodynamic Particle Sizer (APS) at the Korea Global Atmosphere Watch Center (KGAWC) from 6 April, 2006 to 5 April, 2007. Black Carbon (BC), gaseous pollutants of $NO_X$ and $SO_2$ and ${\AA}ngstr\ddot{o}m$ exponent were also measured to examine the properties of the volume size distribution. From distinct difference of the high volume concentration (> $100{\mu}m^3cm^{-3}$), the volume size distribution for each event day was clasified into four types: (1) Type 1 had the high volume concentration for supermicron particles from 2.3 to $6.0{\mu}m$ and maximum average volume concentration was $160.7{\mu}m^3cm^{-3}$ at $3.5{\mu}m$. (2) Type 2 represented the high volume concentration in the both size range of submicron ($0.7-1.0{\mu}m$) and supermicron particles ($2.1-4.1{\mu}m^3cm^{-3}$ and $136.2{\mu}m^3cm^{-3}$ were found at 0.8 and $3.3{\mu}m$ respectively. (3) Type 3 showed the high volume concentration in the size range of $0.5-3.5{\mu}m$ and highest volume concentration of $201.1{\mu}m^3cm^{-3}$ at the particle size bin of $0.8{\mu}m$. (4) Type 4 was characterized by the high volume concentration for the fine particles less than $1.2{\mu}m$ and very high concentration of $446.8{\mu}m^3cm^{-3}$. ${\AA}ngstr\ddot{o}m$ exponent, concentration of gaseous ($NO_X$ and $SO_2$), and particle (BC) pollutants suggested that Type 1 was a typical volume size distribution for the Asian dust and Type 3 provided transportation of air pollutants. The distribution in Type 2 found to have both characteristics of the Asian dust and air pollutants, and Type 4 was took place during the foggy atmosphere containing high density of local pollutants. Based on the properties of volume size distribution, we can identify the three major events contributing the increase of $PM_{10}$ mass concentration, and hope to provide a guideline for discriminating the Asian dust from high $PM_{10}$ events. More case studies and longeto advance this determination method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.2
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• pp.119-126
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• 1983

The purposes of this study are to analyze/model the mode choice behavior of the regional traveler by express bus/express train and to offer useful source in deciding the public transportation policy. The data analyzed were trips of both modes from March, 1980 to November, 1981, between Seoul and other nineteen cities; the data were grouped as five groups according to the change of service variables. Service variables were travel time(unit: minute), cost(:won), average allocation time(:won), service hour(:hour), and dummy variables by mode. As model Logit Model with linear or log utility function were postulated. As the result of this study, some reseanable models were constructed at Model Type I(eq. 2. of this paper) based on the above data except the dummy. It was judged that the parameters calibrated by Group III and Group IV data in table 4, were optimal. Among the parameters, the parameter of travel cost was most reliable. There was a tendency preferring express bus to train in October and November. With the constructed model and Pivot-Point Method. the demand change of express train caused by the service variables' change could be forecasted over 99%.

• Geophysics and Geophysical Exploration
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• v.15 no.4
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• pp.227-234
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• 2012

In this study, we make simulation of density log using a Monte Carlo N-Particle (MCNP) algorithm to make an analysis on density logging under different borehole environments, since density logging is affected by various borehole conditions like borehole size, density of borehole fluid, thickness and type of casing, and so on. MCNP algorithm has been widely used for simulation of problems of nuclear particle transportation. In the simulation, we consider the specific configuration of a tool (Robertson Geologging Co. Ltd) that Korea institute of geoscience and mineral resources (KIGAM) has used. In order to measure accurate bulk density of a formation, it is essential to make a calibration and correction chart for the tool under considerations. Through numerical simulation, this study makes calibration plot of the density tool in material with several known bulk densities and with boreholes of several different diameters. In order to make correction charts for the density logging, we simulate and analyze measurements of density logging under different borehole conditions by considering borehole size, density of borehole fluid, and presence of casing.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.97-107
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• 2024

Despite the rapid advancement in image recognition technology, achieving perfect digitization of tabular documents and handwritten documents still challenges. The purpose of this study is to improve the accuracy of digitizing the logbook by correcting errors by utilizing associated rules considered during logbook entries. Through this, it is expected to enhance the accuracy and reliability of data extracted from logbook through OCR programs. This model is to improve the accuracy of digitizing the logbook of the training ship "Saenuri" at the Mokpo Maritime University by correcting errors identified after Optical Character Recognition (OCR) program recognition. The model identified and corrected errors by utilizing associated rules considered during logbook entries. To evaluate the effect of model, the data before and after correction were divided by features, and comparisons were made between the same sailing number and the same feature. Using this model, approximately 10.6% of errors out of the total estimated error rate of about 11.8% were identified, and 56 out of 123 errors were corrected. A limitation of this study is that it only focuses on information from Dist.Run to Stand Course sections of the logbook, which contain navigational information. Future research will aim to correct more information from the logbook, including weather information, to overcome this limitation.

• Journal of Chest Surgery
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• v.39 no.2 s.259
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• pp.127-133
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• 2006

Background: In the studies of the distribution of time to death in trauma patients, the early deaths within several hours after injury were a large component of total trauma deaths. Due to the development of trauma system, overall mortality of trauma was decreased, but trauma is still the major cause of deaths. Material and Method: From January 1994 to December 2003, trauma patients who had been admitted and had expired at tertiary hospital were enrolled. There was a total of 400 cases, a retrospective study was done to determine the distribution of trauma mortality according to the part of the body that were severely injured part and compared the difference between early deaths within 6 hours and late deaths after 6 hours. We also analysed the risk factors of early deaths due to trauma. Result: In severe injury to the head and abdomen, the distribution of mortality was bimodal. But, in severe chest injuries, the distribution was log-shape and most early deaths were almost of trauma related. The average of GCS were 5.86$\pm$4.15 for the early deaths and 8.24$\pm$5.02 for the late deaths (p < 0.05). The AIS of thorax were 2.66$\pm$1.87 for the early deaths and 1.55$\pm$1.76 for late deaths. The risk factors for early mortality were non-EMS transportation (odds ratio 3.474), high AIS (odds ratio 1.491) and GCS (odds ratio 0.859). Conclusion: In trauma patients, the causes of early mortality were severe brain injury and massive hemorrhage. Also severe chest injuries were the major cause of the early deaths in truama. Early diagnosis of chest injury can frequently be missed in the acute trauma setting. Therefore, high index of suspicion, a careful examination, and aggressive surgical treatment are important in multiple trauma patients.

• Journal of the Mineralogical Society of Korea
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• v.23 no.1
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• pp.1-13
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• 2010

The Yugeum deposit in Youngduk in Gyungsangbuk-do is emplaced in the Cretaceous granitoids located in the Northeastem Gyeongsang Basin. Gold-bearing quartz veins filling the fracture with a direction of $N19^{\circ}{\sim}38^{\circ}W$ are most abundantly distributed within the Younghae granodiorite body. The formation of quartz veins can be classified into three main stages: barren quartz stage, auriferous quartz vein stage, and finally the extensive sulfide mineralization stage. Various sulfide minerals such as pyrite, chalcopyrite, galena, sphalerite, and arsenopyrite were precipitated during the hydrothermal gold mineralization process. Gold commonly occurs as fine-grained electrum in sulfides with high Au concentration (up to 93 wt%) compared to Ag. During the early gold mineralization stage, the temperature and pressure of the fluids are in the range of $220{\sim}250^{\circ}C$ and 730~1800 bar, and the oxygen fugacity is between $10^{-27}$ and $10^{-31.7}$ atm. On the other hand, the fluids of the late stage mineralization are characterized by temperature of $290{\sim}350^{\circ}C$ and pressure of 206~472 bar, and the oxygen fugacity is in the range of $10^{-26.3}{\sim}10^{-28.6}$ atm. The sulfur isotope compositions of sulfide minerals are in the range of $0.2{\sim}4.2^{\circ}/_{\circ\circ}$, while the ${\delta}^{34}SH_2S$ values range from 1.0 to $3.7^{\circ}/_{\circ\circ}$. The Ag/Au atomic ratios of electrum ranges from 0.15 to 1.10, and Au content is higher than Ag in most electrum. During the main gold mineralization stage at the relatively high temperature condition and with pH from 4.5 to 5.5, the stability of ${AuCl_2}^-$ increased while the stability of ${Au(HS)_2}^-$ decreased. Considering the pressure estimated in this deposit, the temperature of the ore fluid reached higher than $350^{\circ}C$ and ${AuCl_2}^-$ became an important species for the gold transportation. As mineralization proceeded with decreasing temperature and increasing pH and $f_{o2}$, the precipitation of sulfide minerals and accompanying electrum occurred.