• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.4
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• pp.63-72
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• 2010

This paper proposes a new authentication protocol for the LR-WPAN. In order to guarantee the reliability and safety of a protocol, this protocol uses the hierarchical authentication approach. In addition, in order to reduce the impact of the denial of service attack, the proposed protocol performs the authentication between a parent router and a joiner device prior to the authentication between a trust center and the joiner device. Moreover, this protocol reduces the authentication delay by decreasing the number of message exchanges during authentication procedure. This paper evaluates the safety of the proposed protocol by the security analysis and reliability of the proposed protocol by the GNY analysis. This paper also compares the number of message exchanges of the ZigBee authentication protocol and the proposed protocol when denial of service attack occurs to evaluate the resistance of the proposed protocol against the denial of service attack. We also analyze the delay for authentication of the joiner device through the implementation of both protocols. Those results show that the proposed protocol effectively protects networks from the denial of service attack and reduces the time for authenticating the joiner device up to maximum 30% as the number of hops increases.

• Convergence Security Journal
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• v.15 no.2
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• pp.69-80
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• 2015

The present study was conducted with aim for establishing the framework of integrated veteran policy for unified Korea through the analysis of the North Korea's veteran policy. For the purpose, this study reviewed the legal system and implementation process concerning the North Korea's veteran policy and analyzed the establishment of fundamental framework of unification and the implications from the North Korea's veteran policy for unified Korea. The review of the North Korea's veteran policy covered the beginning of the North Korea's veteran policy to the present. Based on the findings of the review, this study revealed the necessity of re-establishing the principle of veteran policy in preparation for unification and proposed a plan for unified veteran policy. The results from this study are expected to be a meaningful milestone to unified veteran policy after unification. It is reasonably expected that there will remain considerable differences and conflicting factors, which could block the path to national integration, between two countries and their peoples after unification. Therefore, it is more important to make a thorough preparation and form social consensus than any other. In this respect, national policy for veterans should go back to basics and be reviewed to be ready for unification. Although different in time, the North Korea's veteran policy was and is the base of the nation's system and source engine for development every period. Re-designing the principle of veteran policy should reflect both symbols of the unified nation and the national identity, but also of socially integrated spirit. Therefore, it must include the spirit of patriotism and awareness of national security. Furthermore, as for the integration of veteran policies for unification, it is especially important for two countries to possess and share common historical consciousness. The unified veteran policy should be integrated on this base.

• Journal of The Korean Association For Science Education
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• v.37 no.2
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• pp.335-346
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• 2017

In this study, we developed and examined the validity and reliability of the Test for Indicators of Positive Experiences about Science (TIPES) that measures students' positive experiences about science. We have developed TIPES through literature reviews, development of the preliminary version of TIPES, a pilot test and revisions of the preliminary version, and the test of the final version. Through literature reviews and Delpi methods, we developed the preliminary version of TIPES, which consists of five categories such as science academic emotion, science-related self-concept, science learning motivation, science-related career aspiration, and science-related attitude. Using the preliminary version, we conducted a pilot test with 198 students consisting of 4th, 6th, 8th, and 10th graders, and modified the first version based on the results from the pilot test and expert meetings. We then conducted a main test with the revised version of TIPES with 1,841 students consisting of 4th, 6th, 8th, and 10th graders. According to a confirmatory factor analysis, a reliability test and descriptive statistics analyses, TIPES found to have a good validity as well as reliability. In addition, there are statistically significant differences in the norm distribution and scores of TIPES by student's grade, gender, school location, and level of participation in science-related activities. Discussed in the conclusion are the implications of this research for science education research and science teaching and learning practices in the school.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1021-1026
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• 2012

The transient mass transfer in a single droplet system consisting of 1-octanol (continuous phase)/aqueous succinic acid solution (dispersed phase) was investigated in the presence of chemical reaction, which is acid/anion exchange reaction of succinic acid and tri-n-octylamine (TOA). This succinic acid extraction by TOA can be considered to occur at the interface between organic and aqueous phase, that is, heterogeneous reaction system. The basic properties of the system such as viscosity, density, distribution coefficient, terminal velocity of droplet, and diffusion coefficient were measured experimentally or calculated theoretically, and used for theoretical calculation of characteristic parameters of mass transfer later. The effects of succinic acid concentration on the terminal velocity was negligible in the existence of TOA, although the terminal velocity increases with succinic acid concentration in the absence of TOA. On the contrary, the terminal velocity decreases with TOA concentration. While droplets falls through organic phase, the trajectory of droplets is observed to oscillate around its vertical path. A mass trnasfer cell was prepared to monitor the mass transfer behavior in a single droplet and used to measure the mean concentration of succinic acid inside droplet. The results are expressed with dimensionless parameters. Under 50 g/L succinic acid condition, the system with 0.1 mol/kg TOA showed that the molar flux decreases in proportion to the decrease of concentration gradient, while in the case of 0.5 mol/kg TOA Sh increases rapidly with time indicating the molar flux of succinic acid decreases relatively slowly compared to the decrease in concentration gradient.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.595-602
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• 2005

In order to purify diethylene glycol as main impurity included in p-dioxanone, SLE (solid-liquid equilibria) and mixture density on two components system of p-dioxanone and diethylene glycol were measured and a layered melt crystallization with seed has been applied. The SLE of p-dioxanone and diethylene glycol were a simple eutectic system and the temperature and PDX concentration at eutectic point were 0.08 and 246 K, respectively. Densities of their binary mixtures were well fitted by the best correlation equation, ${\rho}_l=0.405+1.361x+0.002T-0.004xT$. In the melt crystallization, the growth rate (G) was proportional to the 1.5th power of the subcooling degree. The effective distribution coefficient ($K_{eff}$) as the degree of impurity removal was observed to increase with increasing the growth rate and initial p-dioxanone concentration. And also, $K_{eff}$ was correlated with Z function using Wintermantel's model such as $K_{eef}=-0.0604+6.392{\times}Z$. Finally, PDX purity through the optimization of this process can be obtained over 99%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.1
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• pp.108-126
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• 2013

Recently, it becomes essential for firms or nations to forecast the future and identify emerging technologies in order to improve R&D efficiency and gain a competitive advantage. Particularly, the mobile communications industry is characterized by rapid advance and wide application of its technology and thus identifying emerging technologies is more important in the industry than in others. Nevertheless, few attempts have been made to explore its emerging technologies. Therefore, this research aims to develop a methodology to identify the future and emerging technologies especially for the industry and applied it to list top ten emerging technologies for 2020 in the industry. For this purpose, firstly, we focused the key issues in the future targeting 2020 and identified user needs relating to them. Then, candidates of emerging technologies were defined from a set of technologies to meet the needs, for which technological and economic feasibility is assessed to determine their priorities. Finally, the top ten most important technologies were selected and verified. This research is distinct from the previous studies in that it takes a market-pull approach instead of a technology-push approach. The research results are expected to provide valuable information to support strategy- and policy-makings in the mobile communications industry.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.132-137
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• 2008

This experiment was conducted to investigate the effect of supplemental lighting of low light intensities on growth and yield of rose 'Vital' in a forcing culture. Metal halide lamp (MH), High pressure sodium lamp (HSP), and MH+HSP were used as the light sources, and they were set up at a $310\;cm{\times}450\;cm$ interval and at 120cm above the culture beds. Light intensity at 1m point distance from supplemental lighting sources was $32{\sim}34\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Days to the 1st and 2nd harvests decreased by $5{\sim}8$ and $3{\sim}5$days, respectively in supplemental lighting treatment as compared to the control. Days to harvesting was the shortest in MH+HPS treatment, followed by BPS and MH, although there was no significant difference between HPS and MH treatments. The growth was better and incidence of blind shooting decreased by $5{\sim}7%$ in supplemental lighting treatments than the control, increasing marketable cut flowers. The incidence of blind shoot was the lowest in MH+BPS treatment, and there were no significant difference between MH and BPS treatments. In conclusion, supplemental lighting of low light intensities was effective in reducing days to flowering and reduced occurrence of blind shoots.

• Journal of the Korean Magnetics Society
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• v.26 no.3
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• pp.105-114
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• 2016

In this study, For assessment of triangular fibrocartilage complex (TFCC) injury, we acquired images by fat suppressed 3D fast spoiled gradient recalled T1 and fat suppressed Isotropic 3D fast spin echo T1 techniques. For quantitative evaluation, measured signal to noise ratio and contrast to noise ratio and verified statistical significance between two imaging techniques by Mann-Whitney U verification. And for qualitative evaluation, marked 4-grade scoring (0: non diagnostic, 1: poor, 2: adequate, 3: good) on shape of TFCC, artifacts by partial volumes, description of the lesions by two radiologist, verified coincidence between 2 observer using Kappa-value verification. We used 3.0 Tesla MR equipment and 8-channel RF coil for imaging acquisition. As quantitative evaluation results, signal to noise ratio and contrast to noise ratio value of Isotropic 3D fast spin echo T1 technique is higher in every image sections, also between two imaging techniques by Mann-Whitney U verification was statistically significant (p < 0.05). As qualitative results, observer 1, 2 marked a higher grade on Isotropic 3D FSE T1 technique, coincidence verification of evaluation results between two observers by Kappa-value verification was statistically significant (p < 0.05). As a result, during MRI examination on TFCC injury, fat suppressed Isotropic 3D fast spin echo T1 technique is considered offering more useful information about abnormal lesion of TFCC.

• Korea journal of population studies
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• v.26 no.1
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• pp.171-194
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• 2003

The present study investigates the effects of lopsided regional policy and social prejudice on homeownership disparities by household's place of birth of household head in Seoul. The present study utilizes individual household-level census data (2% sample) to evaluate households' residential well-being denoted by homeownership status during the period of 1980-2000. Decomposition techniques based on tenure choice models were used to provide evidences of the home-ownership disparities caused by regional policy and prejudice. We found that households from Gangwon and Honam provinces represent a disproportionately small percentage of homeownership compared with those originated from other provinces. In the statistical analysis, the present study found that having controlled for the factors traditionally thought to influence households' choice of housing tenure, as well as other housing market characteristics in Seoul, place of birth has played a primary role in determining whether or not households become a homeowner. Most strikingly, while most of the disparity in homeownership ratios between households from Youngnam and households from Gangwon in the housing market is due to the endowment differences in human capitals they bring to the market, those between households from Youngnam and households from Honam is largely due to residual differences explained mainly by social discrimination and prejudice against people from Honam. The present study summarized that place of birth has played a primary role in determining whether or not households become a homeowner in Korea. The present study concluded with some policy issues relevant to this study and suggested some future studies.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.16 no.2_3
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• pp.43-51
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• 2010

The changes in quality and shelf life of smoked pork belly according to packaging methods were investigated during storage at $5{\pm}1^{\circ}C$ up to 12 days. Three packaging treatments including air-containing packaging (AC), vacuum packaging (VP), and packaging incorporated with oxygen scavenger (OS) were applied in this experiment. In all treatments, the initial total aerobic plate count (TPC) was 2.4 log cfu/g which was increased with storage period. The rapidest increase of TPC was observed in the AC samples, followed by OS and VP. The VP samples showed inhibiting effects on the growth of Pseudomonas spp. and coliforms over the storage. The TBA values were increased in the order of AC-OS-VP. The VBN values of the VP and OS samples tended to be increased slower than the AC samples during the storage. According to the sensory evaluations, the point of losing marketability in the raw AC, OS, and VP samples was determined to be the day 8, 10, and 12, respectively. However, the evaluations for the cooked samples showed the AC and OS samples preserved the marketing value until the day 10 and 12, while the VP samples until the day 12 except in the parameter of texture. In conclusion, it was found that the most appropriate packaging method for preserving the quality and extending the shelf life of chilled smoked pork belly is vacuum packaging.