• Journal of Food Hygiene and Safety
• /
• v.24 no.4
• /
• pp.312-317
• /
• 2009

Usually, bacterial spores are hundreds or thousands of times more resistant to chemical sanitizers than are vegetable bacteria. Consequently, it is hard to assess whether a commercial sterilant, containing hydrogen peroxide and peracetic acid as ingredients, has or does not have sporicidal activity under certain conditions using the National Standard Test Method for assessing bactericidal activity against Escherichia coli and Staphylococcus aureus. Hence we established alternative the standard test method and requirements to determine whether they are effective in showing at least reduction of $10^3$ in the number of Bacillus subtilis ATCC 6633 spores under the required test condition for evaluation of sporicidal activity including verification methodology. This standardized method has proved to be suitable for evaluating effectiveness of commercial sterilants and could be used as Standardization Test Method for assessing sporicidal activity.

• International Journal of Highway Engineering
• /
• v.10 no.4
• /
• pp.151-159
• /
• 2008

Performances of retroreflectivity vary place to place, according to traffic volumes and time lengths after striping, depending on pavement marking materials and colors. The present paper uses the nation wide data of retroreflectivity, which has been collected from freeways and then tries to develop the regression curve setting traffic volume and service life as independent variables and retroreflectivities as dependent variables. The DB system includes two year's measurement in $2005{\sim}2006$ over Korean freeway pavement marking at an interval of three months for the period. The mobile measurement system, a laserlux, was employed for the purpose. The DB has provided a lot of information about materials and performance of the specific pavement marking such as geometric features, traffic volumes, material characteristics and the installation date. This study provides the comparison of pavement marking performances under diversified conditions. Based on accumulated pavement marking performances, this study provides performance curves based on the diversified factors. The goal of the retroreflectivity modeling is to develop equations that can be used to estimate an average retroreflectivity of pavement markings as a function time since application and traffic volume. After representing the variation of retroreflectivities and estimating regression curves by linear, exponential, logarithmic and power function, the regression curve which had the highest coefficient of determination and the value similar to the last field measurement was regarded as the retroreflectivity decay model. As a result of verification, the decay model showed the signification within the 90% confidence level and especially showed the clear relation with field data according to increase of cumulative vehicle exposure. Accordingly, these models can be used to determine service lives, retroreflectivity degradation rates, and retroreflectivity of new markings.

• Korean Security Journal
• /
• no.17
• /
• pp.91-107
• /
• 2008

This study aims to grasp the general conditions regarding university students in security related majors in Korea. Followings will be covered here: what motivated them to choose those majors, hw much are they git jobs through the education, what is their conscioucness on their majors, jobs, and courses like, and what effects their job preference. And ths study also aims at helping the student with their future plans such as admission to a school of higher grade and choosing their job. For this study, we distributed 340 copies to the students in security related majors at 4 four-year colleges and 1 two-year college, and collected 298 copies by means of quota sampling method. For collected questionnaires, we used individual T-test verification and one-way ANOVA analysis to grasp the situation. Significance stabdard for the test results was set as p<0.05. Followings are the test results. The results on analysis of satisfaction rate on their curriculums, classes, and majors show that students in security-related majors showed different satisfaction rate and different averages according to their sex and the year of the college. In the analysis on the relationship between major education and employment of students in security-related majors, the result of curriculum improvement and scholaril attainments analysis showed statistically significant relation. When students in security-related majors were surveyed on their consciousness of their future plans such as getting jibs, two-year college students had more certificates of qualification for employment than four-year college students.

• Journal of Korean Society of Transportation
• /
• v.21 no.2
• /
• pp.107-118
• /
• 2003

Highway Capacity Manual (HCM) provides an analytical delay estimation model to assist the evaluation of traffic at a signalized intersection. The model revised and included in the HCM published in the year 2000 reflects the results of recent studies and is utilized in various fields of transportation studies. For the implementation of the model in the case of permitted left turns, the HCM supplement provides a computational procedure to adjust the saturation flow rate of permitted left toms. The model however, is originally designed for a protected movement and thus underestimates the delay of permitted left turns due to its difference right-of-way nature. This document describes (1) a review of the theoretical background of the HCM delay estimation model, (2) problems embedded in the model for the delay estimation of permitted left turns, (3) a proposed model developed in this study to improve the delay estimation for permitted left turns and (4) a set of verification tests. In order to reflect various traffic and control conditions in the test, simulation studies were performed to by using the field data based on 120 different permitted left-turn scenarios. Comparison studies conducted between sets of delays estimated by the HCM and the proposed models against a set of the CORSIM delays and showed that the proposed model improved the estimation of the permitted left-turn delays. The explanatory variable of the relationship between the HCM delay and the simulation delay was 0.47 and the one between the delay estimated by the proposed model and the simulation delay was 0.77.

• Journal of Wetlands Research
• /
• v.6 no.4
• /
• pp.45-57
• /
• 2004

This study analyzed the effect of land-use enhancement benefits with the flood safety which it is not quantified in the flood damage analysis, Korea. The land-use enhancement benefits mean the enhancement of land-use value according to the rise of flood safety of the protected area by the flood control projects and we performed the analysis of land-use enhancement benefits with the publicly announced land price which can objectively represent the land-use value of a specific area. We verified the statistical significance of the floating rate of land price according to the effects of flood control projects and the characteristics of a river through the analysis of variance. As a result of the verification, the increase of land-use value was represented by the net annual average floating rate of land price. The flood safety was classified as flood damage potential and flood prevention capacity. The flood damage potential was classified according to the rate of urbanization and flood prevention capacity was represented by the conditional annual non-exceedance probability obtained from the frequency analysis with uncertainty for the flood discharge. The study areas were small urban cities and we calculated the conditional annual non-exceedance probabilities of 200-year flood event for the levees constructed with the conditions of 10- and 50-year design frequency. The result was shown that the net annual average floating rate of land price would be raised nearly 5 times for 10%-increase of the conditional annual non-exceedance probability in small city areas.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.1
• /
• pp.138-149
• /
• 2014

This study proposes an estimation method of strain distribution for multi-span steel beam structure under unspecific loading conditions. The estimation method in this paper employs the curve fitting using the least square method from measured strain data, not analytical method. To verify the proposed estimation method, a static loading test for multi-span steel beam on which distributed and concentrated loads act was conducted. The strain data for verification was measured by FBG sensors that have multiplexing technology. The analysis of the accuracy of strain estimation for distributed and concentrated loads and the errors by considering the number of measured points used in the estimation were conducted. In the maximum strain points, the strains could be estimated with the errors of 5.89% (loading step 1) and 6.26% (loading step 2). In case of decreasing the number of sensors, it was also confirmed that the errors increased (0.26~0.37%). Through the curve fitting method, it is possible to estimate the strain distribution (maximum strains and their locations) of multi-span beam for unspecific loads and go over the limit of the analytical estimation method which is suitable for specific distributed loads.

• Journal of Korean Society of Disaster and Security
• /
• v.10 no.1
• /
• pp.1-10
• /
• 2017

Recently, increasing cases of ground subsidence in the urban area has become social issue, and related bill has been passed. Ground subsidence occurs through complex combination of various factors, and numerical analysis of this problem is limited thereby. This is why verification of ground subsidence mechanism has been conducted through physical modelling. Previous researches has been focused on modelling ground subsidence caused by utility pipe defects, and there has been insufficient physical modelling study on ground subsidence caused by various reasons such as groundwater flow and excavation activity. Also, most previous physical modelling studies were performed in 1g condition, which cannot take the in-situ stress condition into the evaluation of the ground subsidence mechanism. Therefore, in this study, physical modelling techniques to simulate various conditions is discussed by studying the previous researches on the ground subsidence mechanism through physical modelling. Also, centrifuge modelling test is suggested in this study as the technique to perform more reliable evaluation of ground subsidence mechanism. Lastly, this study suggests to apply the techniques used in the evaluation of ground subsidence mechanism into Ground Stability Assessment.

• Ecology and Resilient Infrastructure
• /
• v.6 no.4
• /
• pp.217-226
• /
• 2019

Optimum engineering methods for bank protection were classified based on steepness of bank slope and an existence of waterfront facility in the floodplain, and a new concept of eco-hybrid rolling mat method which could be applicable for the unfitted cases with previously developed countermeasures was suggested in this study. The eco-hybrid rolling mat method can be constructed while maintaining the river environment and ecosystem that does not interfere with the ground and slopes, when bank erosion occurs, it is an economical and efficient construction method that can protect the revetment and the bank slope immediately. The developed eco-hybrid rolling mat method was verified for the designed structure, system, function and effect based on large-scale river experiments including field exposure and decomposition test. As a result, the normal operation and effect of the rolling mat ted under low and high velocity conditions were confirmed with respect to bank protection. The effect of bank erosion prevention was quantitatively validated by sediment concentration monitoring and analysis, and the product specification of the eco-hybrid rolling mat was presented based on the standardized mat applied in real-scale tests.

• Management & Information Systems Review
• /
• v.33 no.1
• /
• pp.99-118
• /
• 2014

This study is a product launch strategy Preannouncing companies associated with temporal distance( in the near future/ distant future) and prior knowledge level(high knowledge/ low knowledge), the memory - based judgments(Global product judgment/ Discrete product judgment) and the purchase intention appears, the difference between the empirical verification of what was discriminatory. The study, first, Preannouncing main effect of temporal distance on judgments remember the difference between the purchase intention and consistent global product judgment is more discrete product judgment were higher awareness, purchase intention is higher. Second, Preannouncing high level of product knowledge in global product judgment showed that compared to discrete product judgment. In addition, low levels of knowledge than a discrete product judgment that global product judgment and purchase intention shown that a high level of consumer knowledge through systematic information processing and the road leads to higher purchase attitude. Third, Preannouncing according to the temporal distance and level of knowledge about the interaction effect results in the near future in terms of the high level of knowledge consumers global product judgment was higher than the discrete product judgment. On the other hand, a low level of knowledge of conditions in the distant future, consumers are more discrete product judgment recognized global product judgment showed that high.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.38 no.3
• /
• pp.112-126
• /
• 1996

This study was conducted to develop an optimal runoff bydrograph model by comparison of the peak discharge and time to peak between observed and simulated flows derived by four different models, that is, linear time-invariant, linear time-variant, nonlinear time-invariant and nonlinear time-variant models under the conditions of heavy rainfalls with regionally uniform rainfall intensity in short durations at nine small watersheds. The results obtained through this study can be summarized as follows. 1. Parameters for four models including linear time-invariant, linear time-variant, nonlinear time-invariant and nonlinear time-variant models were calibrated using a trial and error method with rainfall and runoff data for the applied watersheds. Regression analysis among parameters, rainfall and watershed characteristics were established for both linear time-invariant and nonlinear time-invariant models. 2. Correlation coefficients of the simulated peak discharge of calibrated runoff hydrographs by using four models were shown to be a high significant to the peak of observed runoff graphs. Especially, it can be concluded that the simulated peak discharge of a linear time-variant model is approaching more closely to the observed runoff hydrograph in comparison with those of three models in the applied watersheds. 3. Correlation coefficients of the simulated time to peak of calibrated runoff hydrographs by using a linear time-variant model were shown to be a high significant to the time to peak of observed runoff hydrographs than those of the other models. 4. The peak discharge and time to peak of simulated runoff hydrogaphs by using linear time-variant model are verified to be approached more closely to those of observed runoff hydrographs than those of three models in the applied watersheds. 5. It can be generally concluded that the shape of simulated hydrograph based on a linear time-variant model is getting closer to the observed runoff hydrograph than those of three models in the applied watersheds. 6. Simulated hydrographs using the nonlinear time-variant model which is based on more closely to the theoritical background of the natural runoff process are not closer to the observed runoff hydrographs in comparison with those of three models in the applied watersheds. Consequently, it is to be desired that futher study for the nonlinear time-variant model should be continued with verification using rainfall-runoff data of the other watersheds in addition to the review of analyical techniques.