• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.120-129
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• 2023

To evaluate the vertical loads on railway bridges, conventional load tests are typically conducted. However, these tests often entail significant costs and procedural challenges. Railway conditions involve nearly identical load profiles due to standardized rail systems, which may appear straightforward in terms of load conditions. Nevertheless, this study aims to validate load tests conducted under operational train conditions by comparing the results with those obtained from conventional load tests. Additionally, static and dynamic structural behaviors are extracted from the measurement data for evaluation. To ensure the reliability of load testing, this research demonstrates feasibility through comparisons of existing measurement data with sensor attachment locations, train speeds, responses between different rail lines, tendency analysis, selection of impact coefficients, and analysis of natural frequencies. This study applies to the Dongho Railway Bridge and verifies the applicability of the proposed method. Ten operational trains and 44 sensors were deployed on the bridge to measure deformations and deflections during load test intervals, which were then compared with theoretical values. The analysis results indicate good symmetry and overlap of loads, as well as a favorable comparison between static and dynamic load test results. The maximum measured impact coefficient (0.092) was found to be lower than the theoretical impact coefficient (0.327), and the impact influence from live loads was deemed acceptable. The measured natural frequencies approximated the theoretical values, with an average of 2.393Hz compared to the calculated value of 2.415Hz. Based on these results, this paper demonstrates that for evaluating vertical loads, it is possible to measure deformations and deflections of truss railway bridges through load tests under operational train conditions without traffic control, enabling the calculation of response factors for stress adjustments.

• Journal of Preventive Medicine and Public Health
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• v.36 no.4
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• pp.303-313
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• 2003

General information is summarized, that is necessary to introduce a scientific assessment of the human health and exposure issue concerning dioxin and dioxin-like compound. Scientific literatures were reviewed to assess the background exposures to the dioxin-like compounds for normal residents. Epidemiologic studies were also reviewed to assess malignant and nonmalignant sweets of dioxins. In 1997, the International Agency for Research on Cancer classified 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as a human carcinogen, primarily based on occupational cohort studies. The US Environmental Protection Agency made the same decision in it's Draft Dioxin Reassessment. Epidemiologic evidences point to a generalized excess of all cancers, without any pronounced excess at specific sites. Reported non-cancer effects included a range of conditions affecting most systems. Among them, chloracne, elevation in gamma glutamyl transferase(GGT), and alterations in reproductive hormones are related to TCDO, Other adverse outcomes, such as lipid concentrations, diabetes, circulatory and heart diseases, immunologic disorders, neurobehavioral effects, and developmental outcomes require further study before their respective relationships to TCDD can be more definitively assessed.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.97-104
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• 2004

Double-layered polysulfone composite films, containing cerium activated yttrium silicate (CAYS) as a flour, were prepared from double casting of two polymeric solutions, and their morphology and physical strength were superior to those of single-layered composites. The prepared polymeric films consist of a dense bottom layer and a CAYS-holding top layer. The former is made of coagulating the polysulfone and methylene chloride binary solution and works as a supporter to improve the composite's physical strength, while the latter holding the inorganic fluor plays a role as an active site to detect the radioactive contamination. The prepared films revealed two distinguished, but tightly attached, double layers, their attachment being identified by morphology of the interface between two layers. As prepared by water immersion coagulation, the films have highly developed macropores, compared with a dense structure in the film prepared by evaporation. In the radionuclide detection test of the CAYS-impregnated composites, the films have reliable detection capacity at a radionuclide spotting test. The double-layered composites with the dense support layer show a better stability in holding the radionuclides spotted on the surface as well as an improvement in physical strength, compared with the single-layer composites having shortcomings such as being too porous or being brittle.

• Fire Science and Engineering
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• v.30 no.2
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• pp.27-34
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• 2016

This paper studies a fire detection system using an optical fiber linear detector which can minimize damage from a fire by the most adaptable even in poor environmental conditions such as a tunnel or utility-pipe conduit vulnerable to fire. Using a strand of optical fiber, temperature can be displayed in intervals of meters and a fire can be detected remotely from a distance of several kilometers. Thanks to its strengths such as high reliability and long life, it is widely applied in harsh environments in the overseas. Therefore demands are expected to grow greatly in Korea as well. However, all optical signal drive and analysis module except for the optical fiber linear detector, tend to rely on import. Firstly this study deduced the location and the method of processing signals measuring temperature by using the optical fiber linear detector in order to develop a technology for a domestic model of fire detection system. Secondly this study designed and manufactured the optical analysis test module, and then we checked its performance.

• Journal of Technology Innovation
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• v.25 no.4
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• pp.165-187
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• 2017

This study analyzed the effects of TLO's organization size, expertise, and economic compensation on technology transfer performance using the panel data of Government-Funded Research Institutes in 2013-2016. First, the size of TLO personnel and budget have a positive effect on the technology transfer performance. However, in the case of TLO manpower, the statistical significance of the effect on the number of technology transfers was only 90%, and it did not affect royalty. Second, TLO expertise has a strong impact on technology transfer performance. It shows that the number of professional license holders, such as patent attorney or a technology valuer, has a statistically significant effect on the increase of the technology transfer number and the royalty under the 99% confidence level. However, unlike expected, the size of the Ph.D. did not seem to have any effect on technology transfer performance. Finally, the economic compensation for TLO does not affect both the number of technology transfers and the royalty. It does not seem to work as an appropriate incentive system, because the absolute size of the compensation is too small. The results of the above analysis suggest that it is important to secure expertise in order for the TLO organization to play a substantial role, and it is necessary to improve the economic compensation system to attract TLOs to technology transfer.

• Korean journal of communication and information
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• v.42
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• pp.44-78
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• 2008

The present study explored the agenda setting effects of replies called "Daet-Gul", and perception of the news replies. This study has established three research questions: 1) the recognition of the online communication 2) the degree of the reading and writing on online spare 3) the amount of the effects on the online communication. This study is performed using survey method. The survey results indicated in that the participants are very passive readers and writers on the online spare. In addition, the survey repliers evaluated that replies' mechanical device and antigravitational speed have high score, whereas they marked low store in the content and credibility of 'the replies. Therefore, they did not estimate the effects of the replies highly. All the results indicate that 'the replies' is not the fundamental factors of the deliberative democracy. It's because online communication with 'the replies' are thought to be fated the abuse and slander. Therefore, it's essential to improve the online communication with 'the replies', through the introduction of the 'trackback', which is a sort of the 'remote replies'

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.674-680
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• 2012

As(III) and As(V) were analyzed in bamboo salts by hydride generation ICP-AES. In order to quantify the total amount of As in bamboo salts, $AsH_3$ was producted by reacting with 6 mol/L hydrochloric acid and $NaBH_4$, which was then analyzed by hydride generation ICP-AES. As(V) was quantified simultaneously after selectively quantifying As(III). As(III) was quantified by determining the total amount of As and then correcting for the amount of As(III). To improve the reliability of the analysis we repeated the experiment several times to check the detection limit, quantification limit, and measurements of our testing methods. According to the result of our quantification analysis of As existing in bamboo salt, the range of total As content was 0.05 mg/kg~0.2 mg/kg and As(V) was over 90% of the total As.

• Korean Journal of Biological Psychiatry
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• v.5 no.2
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• pp.243-247
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• 1998

The authors tried to confirm the significant changes of plasma homovanillic acid(HVA) concentration after insulin administration in comparison with those of usual diurnal variation in the same subjects. Male patients with schizophrenia taking neuroleptics were participated in a study of diurnal variation and insulin induced dopaminergic perturbation, with multiple samplings at baseline, 30minutes, 60minutes and 90minutes after insulin administration(n=18). Ten patients were sampled at baseline and 60minutes after insulin administration. There was a diurnal variation of plasma HVA concentrations, which decreased gradually from 8 am to 9:30 am. We confirmed that regular insulin(0.1 unit/kg) blocked the normal diurnal variations and increased plasma HVA concentrations. This pattern was not correlated with clinical variables, such as age, onset age, duration of illness and presence of family history. Schizophrenic patients were grouped by the positive and negative syndrome scale. In contrast to our previous study, the concentrations of positive and negative groups were similar at baseline. The HVA concentrations of negative group after insulin administration were higher than those of positive group without statistical significance. We have a plan to modify the current insulin-HVA method. In the near future, we will try to confirm whether the modified insulin-HVA method can be used as a biological indicator for the elucidation of complex clinical manifestations of schizophrenia.

• Journal of Veterinary Clinics
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• v.26 no.2
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• pp.134-137
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• 2009

Although there is circumstantial evidence that infectious bronchitis(IB) in the Korean layer industry has contributed to severe economic losses, the seroprevalence against IB virus(IBV) and risk factors associated with seropositivity are not well known. During May to October 2007, 820 blood samples were randomly collected from 41 laying hen flocks(20 birds in each flock) with $\geq$ 3,000 birds of 18 week of age or older in three provinces of Korea. The samples size was determined considering a flock-size range of 3,000-65,000 birds, an expected bird-level seroprevalence of $\geq$ 15%, and a 95% level of confidence. Serum samples were examined using a hemagglutination inhibition test for antibodies to IBV. The overall apparent flock-level seroprevalence was 46.3%(95% CI, 31.1-66.6) with no statistically significant differences among provinces(X=1.205, p>0.05). There were 19 positive flocks with one to eight seropositive birds, and 11 of these had one or two seropositive birds. None of the measured parameters were significantly associated with seropositivity against IBV in a subsequent multivariable logistic regression analysis. A longitudinal risk factor studies considering management and vaccination characteristics possibly associated with the IBV flock prevalence would be beneficial.

• Journal of the Korean Geotechnical Society
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• v.21 no.8
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• pp.63-72
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• 2005

Rocks are dumped to soft marine ground in order to improve trafficability and construction conditions in the tideland reclamation construction sites. Though this rock layer under earth fill has caused in a serious seepage problems after construction, seepage behaviors of this embankment structure is not correctly investigated. Water flow through rock layers is, in general, known as Non-Darcy's flow. However, the embedded rock layer under earth fill is not known whether its flow is governed by Darcy's or Non-Darcy's law. Therefore, a numerical analysis, laboratory model test and filed investigations were performed for analyzing the those seepage characteristics in this research. Results show that there is significance of $95\%$ of confidence between observed heads and seepage rates, and the calculated ones by SAMTLE which is developed under the assumption that the water flows through the two-layer system obey the Darcy's flow. And after operating the hydraulic gradient(i) of $0.10\~0.55$ upon laboratory model, these seepage characteristics of the embedded rock layer show that Reynolds Numbers are less than 10 and the relationship between these velocities of rock layer(v) and hydraulic gradients(i) is linearly proportional with more than 0.79 of the coefficient of correlation $(R^2)$. And the Reynolds Number of the velocity calculated by the relation of v=ki in the embedded rock layer of OO sea dike is $1\~6$. It shows also laminar flow. Based on these results, it is concluded that the seepage characteristics of embedded rock layer under earth fill can be laminar and Darcy's flow.