• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.1010-1020
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• 2014

This study intended to compare and analyze the difference between resilience and academic stress of juveniles depending on having experience in participating in the camp, and furthermore, to analyze how the camping participation degree of juveniles affect resilience and academic stress. To do so, this study selected teenagers as a population among camping ground users located in Chungcheong and Kyunggi region in 2014, sampled out total 300 participants of 150 camping participants and 150 non-participants using purposive sampling method, then selected final 295 subjects for the final analysis. Validity and credibility of questionnaire were verified through factor analysis and reliability analysis. For data processing, the t-test and multiple regression analysis were used using SPSSWIN 18.00 program. Conclusions are as follows. First, the camp participant group of juveniles showed higher resilience than the non-participant group. Secondly, it was identified that among camping participation degree of juveniles, the resilience of positivity decreased when the length of stay was longer. Thirdly, the camp participant group of juveniles showed lower academic stress than the non-participant group, but did not who significant difference statistically. Fourthly, the school record stress and assignment stress decreased when the participation degree, the length of stay, among camping participation degree of juveniles was longer. Fifthly, it was identified that the better the resilience strengthened by participating in the camp, the academic stress decreased.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.3
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• pp.179-196
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• 1986

In this paper, the peformance of a statistical packet voice/data multiplexer is studied. In ths study we assume that in the packet voice/data multiplexer two separate finite queues are used for voice and data traffics, and that voice traffic gets priority over data. For the performance analysis we divide the output link of the multiplexer into a sequence of time slots. The voice signal is modeled as an (M+1) - state Markov process, M being the packet generation period in slots. As for the data traffic, it is modeled by a simple Poisson process. In our discrete time domain analysis, the queueing behavior of voice traffic is little affected by the data traffic since voice signal has priority over data. Therefore, we first analyze the queueing behavior of voice traffic, and then using the result, we study the queueing behavior of data traffic. For the packet voice multiplexer, both inpur state and voice buffer occupancy are formulated by a two-dimensional Markov chain. For the integrated voice/data multiplexer we use a three-dimensional Markov chain that represents the input voice state and the buffer occupancies of voice and data. With these models, the numerical results for the performance have been obtained by the Gauss-Seidel iteration method. The analytical results have been verified by computer simylation. From the results we have found that there exist tradeoffs among the number of voice users, output link capacity, voic queue size and overflow probability for the voice traffic, and also exist tradeoffs among traffic load, data queue size and oveflow probability for the data traffic. Also, there exists a tradeoff between the performance of voice and data traffics for given inpur traffics and link capacity. In addition, it has been found that the average queueing delay of data traffic is longer than the maximum buffer size, when the gain of time assignment speech interpolation(TASI) is more than two and the number of voice users is small.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.1
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• pp.15-24
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• 2001

The purpose of this study is to evaluate the tissue response in applying of various bone substitutes included toothash-plaster mixture, resorbable hydroxylapatite (HA) and demineralized freeze-dried bone and to show the clinical usefulness of toothash-plaster mixture for the repair of craniomaxillofacial bone defect. For this experiment, 100 Sprague-Dawley rats weighing 200gm or more were used. There were four experimental groups: group I, toothash-plaster mixture; group II, demineralized freeze-dried bone; group III, resorbable HA; and group IV, control group. A full thickness, round bone defect measuring 10mm in diameter was created in the midcranium, and the substitutes cited above were embedded in the experimental rats based on their group assignment. Blood clot was filled in the rats assigned to the control group. Experimental rats were sacrificed on the 1st, 3rd, 5th, 8th, 12th and 24th week after implantation and stained with the hematoxylineosin, Masson's Trichrome, using Van Gieson's stain method, and were examined under light microscope. The results were as follows: 1. In all the groups, prominent inflammatory reaction and the infiltration of multinucleated giant cells were noted during the early stage. Gradual healing decreased this reaction. 2. Among the rats in the experimental group II, which were given demineralized freeze-dried bone implants, active formation of new bone traveculae manifested. Chondroid tissues appeared, and it was suggested that the defect was filled with newly formed bone by virtue of osteoinductive activity. On the 12th week after the experiments, most of the defect was filled with newly formed bone trabeculae. 3. In experimental groups I and III, it was noted that HA manifested a healing process similar to that characterized by the toothash-plaster mixture, but inflammatory reaction was more prominent in experimental group I. Active osteoblasts were observed along the periphery of osteoid tissues, while newly formed bone trabeculae appeared adjacent to the implanted materials three weeks later. Formation increased to the extent that newly formed bone trabeculae fused directly with the host bone. Increase in new bone ingrowth into the filling materials was revealed by both experimental groups. 4. In the control group, new bone formation adjacent to the host bone was observed, but most of the defect was filled with mature connective tissue 24 weeks after the experiments.

• Journal of Environmental Health Sciences
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• v.39 no.2
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• pp.117-129
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• 2013

Background: This study was carried out for the purpose of comprehensively evaluating the mercury exposure level of residents in several areas and the correlation between hair mercury concentration and blood mercury concentration. Method: One thousand one hundred ninety seven subjects were sampled from 30 sites using random assignment sampling. We performed a questionnaire survey and measured the level of total mercury in hair and blood samples from all subjects. Results: The geometric mean concentrations of hair and blood mercury in all subjects were 1.27 mg/kg [95% confidence interval (CI): 1.23-1.32 mg/kg] and 5.24 ${\mu}g/L$ [95% CI: 5.07-5.41 ${\mu}g/L$], respectively. Male (1.56 mg/kg in hair, 6.00 ${\mu}g/L$ in blood) was significantly higher than that of female (1.03 mg/kg in hair, 4.56 ${\mu}g/L$ in blood), and the concentrations were elevated as age increased up to the 50s. Education, smoking, alcohol drinking, and using of pesticides were also shown to influence mercury concentrations in hair and blood. The ratio of hair/ blood mercury concentration was 261.3. The total mercury concentration in hair was identified to be significantly related with total mercury concentration in blood (r=0.814, p<0.001). Conclusion: The geometric mean concentrations of hair and blood mercury were higher than the levels provided in international recommendations. The total mercury concentration in hair was positively correlated with the concentration in blood. The results of this study suggest that hair mercury be considered as a useful tool for the evaluation of mercury exposure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.809-819
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• 2004

In this paper, in order to exclude the expansion of M/W relay frequency or its new frequency assignment possibly, we analyzed a possibility of substituting M/W system by B-WLL or optical fiber network regarding service quality and economical points. To define the target of service quality, pre-condition and analysis method for the selected media have been derived to compare each other. E1 transmission with BER 10$^{-1}$ was chosen as a reference capacity, and service distance was calculated f3r the selected media as a function of availability. Also from the economical point we considered 3 systems such as optical fiber, M/W, and B-WLL based upon basic system structure, and analyzed them for various line configurations of fiber optic and B-WLL according to service period, system capacity, transmission distance, and data rate. It was confirmed that B-WLL can provide quality of service with 99.999 % availability within 1.6 km cell radius, and for optical fiber substitution, the leased fiber conduit on an electric pole is more economical than M/W system irrespective of service period, but in case of directly digging for underground conduit, it turned out ineffective regardless of cabling duct types.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2001.06a
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• pp.149-153
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• 2001

To investigate the mode of bactericidal action for antimicrobial peptide, pediocin, synthetic and mutant pediocins were prepared by direct chemical synthesis. Native pediocin was purified from Pedio-coccus acidilactici M and its conformational structure and bactericidal functions were analyzed and compared to synthetic pediocin. Schematic mode of pediocin actions, how pediocin binds on the target cell membrane, penetrates and makes tunnel are proposed. For these purposes, primary and secondary structures of pediocin was analyzed and disulfide bond assignment was also done. The pediocin purified from P. acidilactici M had high effective bactericidal ability against gram positive bacteria, especially Listeria monocytogenes and was very stable at extreme pHs and even at high temperatures such as autoclaving temperature (121$^{\circ}C$). Pediocin was consisted of 44 amino acids with four cysteines. Novel synthetic peptides were achieved by solid phase peptide synthesis(SPPS) method. To explain the function of cysteine in C-terminal region, mutant pediocin, Ped[C24A＋C44A], was synthesized and their structural and biological functions were analyzed. Second mutant pediocin, Ped[KllE], was prepared to explain the function of lysine at 11 of N-terminal part of pediocin, especially loop of $\beta$-sheet, and to predict the initial binding site of pediocin. The native and synthetic pediocins was showed random coil conformation by spectropolarimetry in moderate conditions. This conformation was observed in extreme conditions such as high temperature and low and high pHs, also. Circular dichroism(CD) data also showed the existence of $\beta$-turn structure in N-terminal part both native and synthetic pediocins. A structural model for pediocin predicts that 18 amino acids in the N-terminal part of the peptide assume a three-strand $\beta$-sheet conformation. This random coil in C-terminal part of pediocin was converted to folding structure, helix structure, in nonpolar solvents such as alcohol and TFE. The disulfide bond between $^{9}$ Cys and $^{14}$ Cys was concrete and inevitable, however, evidences of disulfide bond between $^{24}$ Cys and $^{44}$ Cys was not. Data of Ped[C24A＋C44A], pediocin mutant showed that $^{44}$ Cys was required during killing the target cells but not inevitable, since Ped[C24A＋C44A] still have bactericidal activity but much less than native pediocin. Another pediocin mutant, Ped[KllE], had still bactericidal activity, was controversial to propose that positive charge like as $^{11}$ Lys in loop or hinge in bacteriocin bound or helped to binding to microorganism with electrostatic interaction between cell membrane especially teichoic acid and positive amino acid nonspecifically. The conformation of pediocin among native, synthetic and mutant pediocins did not show big difference. The conformations between oxidized and reduced pediocin were almost similar regardless of native or synthetic.

• Journal of Preventive Medicine and Public Health
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• v.37 no.4
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• pp.381-389
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• 2004

Objective : To compare the efficacy between SKI306X and Diclofenac by using generalized estimating equations (GEE) methodology in the analysis of correlated bivariate binary outcome data in Osteoarthritis (OA) diseases. Methods : A randomized, double-blind, active comparator-controlled, non-inferiority clinical trial was conducted at 5 institutions in Korea with the random assignment of 248 patients aged 35 to 75 years old with OA of the knee and clinical evidence of OA. Patients were enrolled in this study if they had at least moderate pain in the affected knee joint and a score larger than 35mm as assessed by VAS (Visual Analog Scale). The main exposure variable was treatment (SKI 306X vs. Diclofenac) and other covariates were age, sex, BMI, baseline VAS, center, operation history (Yes/No), NSAIDS (Y/N), acupuncture (Y/N), herbal medicine (Y/N), past history of musculoskeletal disease (Y/N), and previous therapy related with OA (Y/N). The main study outcome was the change of VAS pain scores from baseline to the 2nd and 4th weeks after treatment. Pain scores were obtained as baseline, 2nd and 4th weeks after treatment. We applied GEE approach with empirical covariance matrix and independent(or exchangeable) working correlation matrix to evaluate the relation of several risk factors to the change of VAS pain scores with correlated binary bivariate outcomes. Results : While baseline VAS, age, and acupuncture variables had protective effects for reducing the OA pain, its treatment (Joins/Diclofenac) was not statistically significant through GEE methodology (ITT:aOR=1.37, 95% CI=(0.8200, 2.26), PP:aOR=1.47, 95% CI=(0.73, 2.95)). The goodness-of-fit statistic for GEE (6.55, p=0.68) was computed to assess the adequacy of the fitted final model. Conclusions : Both ANCOVA and GEE methods yielded non statistical significance in the evaluation of non-inferiority of the efficacy between SKI306X and Diclofenac. While VAS outcome for each visit was applied in GEE, only VAS outcome for the fourth visit was applied in ANCOVA. So the GEE methodology is more accurate for the analysis of correlated outcomes.

• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.71-79
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• 2011

Traditionally, a dynamic network model is considered as a tool for solving real-time traffic problems. One of useful and practical ways of using such models is to use it to produce and disseminate forecast travel time information so that the travelers can switch their routes from congested to less-congested or uncongested, which can enhance the performance of the network. This approach seems to be promising when the traffic congestion is severe, especially when sudden incidents happen. A consideration that should be given in implementing this method is that travel time information may affect the future traffic condition itself, creating undesirable side effects such as the over-reaction problem. Furthermore incorrect forecast travel time can make the information unreliable. In this paper, a network-wide travel time prediction model under incidents is developed. The model assumes that all drivers have access to detailed traffic information through personalized in-vehicle devices such as car navigation systems. Drivers are assumed to make their own travel choice based on the travel time information provided. A route-based stochastic variational inequality is formulated, which is used as a basic model for the travel time prediction. A diversion function is introduced to account for the motorists' willingness to divert. An inverse function of the diversion curve is derived to develop a variational inequality formulation for the travel time prediction model. Computational results illustrate the characteristics of the proposed model.

• Journal of the Korean Chemical Society
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• v.31 no.6
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• pp.555-566
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• 1987

Fifty ancient Korean coins originated in Yi Dynasty have been determined for 9 elements such as Sn, Fe, As, Ag, Co, Sb, Ir, Ru and Ni by instrumental neutron activation analysis and for 3 elements such as Cu, Pb, and Zn by atomic absorption spectrometry. Bronze coins originated in early days of the dynasty contain as major constituents Cu, Pb and Sn approximately in the ratio 90 : 4 : 3, whereas, those in latter days contain in ratio 7 : 2 : 0. Brass coins which had begun in 17 century contain as major constituents Cu, Zn and Pb approximately in the ratio 7 : 1 : 1. The multivariate data have been analyzed for the relation among elemental contents through the variance-covariance matrix. The data have been further analyzed by a principal component mapping method. As the results training set of 8 class have been chosen, based on the spread of sample points in an eigen vector plot and archaeological data such as age and the office of minting. The training set and test set of samples have finally been analyzed for the assignment to certain classes or outliers through the statistical isolinear multiple component analysis (SIMCA).

• Journal of the Korean Society for Library and Information Science
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• v.49 no.2
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• pp.255-274
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• 2015

This study aims to define the user experience and to evaluate the usability toward electronic publication for education and research. As research methods, After total 20 people of 10 undergraduate students and 10 graduate students were randomly selected as the subjects, the research was conducted by using the in-depth interview and the e-book reader experimental method. As the results of analysis about subjective preferences in case of using academic resources, The subject relevance and understandability were responded as most important factors for selecting academic resources. And the most frequent purposes for using academic resources were to perform an assignment and to write an article. As the results of analysis about the user experience for using the print media and electronic media, the user experience of the print media is more positive than the electronic media and especially these results were caused by academic situation. Many subjects responded that the electronic media is more inconvenient in case of using academic resources. As a result of the e-book reader usability test, the hardware test score (3.47) is higher than the software test score (3.31).