• Journal of Environmental Health Sciences
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• v.48 no.1
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• pp.9-18
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• 2022

In today's civilization, it can be impossible to prevent disasters that cause large-scale human and material harm, and the environmental industry is not excepted from this. Over the last 50 years, several large and small environmental health catastrophes have occurred in Korea. Notable instances include the phenol pollution accident in the Nakdong River, the Hebei Spirit oil spill in Taean, Chungcheongnam-do, and the humidifier disinfectant disaster. Looking at these instances, it is clear that the government failed to prevent similar incidents and accidents after the tragedies. The government created and executed different policies to prevent such incidents and accidents, but the majority of them were highly fragmented. It is understandable that depending on the political and social level of the society in which the environmental health hazard incident/accident happened, the investigation of the cause, countermeasures, and policy reaction may differ. To put it another way, the more authoritarian and non-democratic a political social system is, the more likely it is to cover up occurrences and accidents without a deep examination. This is in line with the members of society's level of political awareness and acknowledgment of the importance of life and safety. In 1985, when the Onsan pollution disease was discovered, and in 2011, when we recognized the realities of the humidifier disinfectant disaster, South Korea's political and social systems were entirely different.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.355-362
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• 2008

A reliability model of Level II AFDA is proposed to analyze the wave run-up occurring by the interaction of incident waves and sloped coastal structures. The reliability model may be satisfactorily calibrated by Level III Monte-Carlo simulation. Additionally, the partial safety factors of random variables related to wave run-up can be straightforwardly evaluated by the inverse-reliability method that use influence coefficients and uncertainties of random variables, and target probability of failure. In particular, a design equation for wave run-up is derived in the same form as that of deterministic design method so that the reliability-based design method of Level I may be applied easily. Finally, it is confirmed that results redesigned by the reliability-based design method of Level I with partial safety factors suggested in this paper are satisfactorily compared with results of CEM(2006) as well as those of Level II AFDA.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.3
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• pp.211-219
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• 2014

Closed cracks are difficult to detect using conventional ultrasonic testing because most incident ultrasound passes completely through these cracks. Nonlinear ultrasound inspection using sub-harmonic frequencies a promising method for detecting closed cracks. To implement this method, a sub-harmonic phased array (PA) is proposed to visualize the length of closed cracks in solids. A sub-harmonic PA generally consists of a single transmitter and an array receiver, which detects sub-harmonic waves generated from closed cracks. The PA images are obtained using the total focusing method (TFM), which (with a transmitter and receiving array) employs a full matrix in the observation region to achieve fine image resolution. In particular, the receiving signals are measured using a laser Doppler vibrometer (LDV) to collect PA images for both fundamental and sub-harmonic frequencies. Oblique incidence, which is used to boost sub-harmonic generation, inevitably produces various surface waves that contaminate the signals measured in the receiving transducer. Surface wave interference often degrades PA images severely, and it becomes difficult to read the closed crack's position from the images. Various methods to prevent or eliminate this interference are possible. In particular, enhancing images with signal processing could be a highly cost-effective method. Because periodic patterns distributed in a PA image are the most frequent interference induced by surface waves, spatial frequency filtering is applicable for removing these waves. Experiments clearly demonstrate that the spatial frequency filter improves PA images.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.103-110
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• 2012

PURPOSES : In Korea, over 70 percent of the land consists of mountainous and rolling area. Thus, tunnels continue its upward trend as road network are extended. In these circumstances, the importance of tunnel has been increased nowadays and then its safety investigation and research should be performed. This study is focus on confirming and improving the safety of tunnel. On tunnel hood, sunglare effect can irritate driver's behavior instantly and this can result in incident. METHODS : The study of this phenomenon is rarely conducted in domestic and foreign papers, so there is no proper measure for this. This study analyzes the driving environment of the effect of sunglare effect on tunnel hood. RESULTS : Traffic accidents stem from complex set of factors. This study build the Traffic Accident Prediction Models to find out the effect of sunglare effect on tunnel's hood. The independent variables are traffic volume, geometric design of road, length of tunnel and road side environment. Using these variables, this model estimates accident frequency on tunnel hood by Poisson regression model and Negative binomial regression model. Although Poisson regression model have more proper goodness of fit than Negative binomial regression model, Poisson regression model has overdipersion problem. So the Negative binomial regression model is used in this analysis. CONCLUSIONS : Consequently, the model shows that sunglare effect can play a role in driving safety on tunnel hood. As a result, the information of sunglare effect should be noticed ahead of tunnel hood so this can prevent drivers from being in hazard situation.

• Korean Journal of Food Science and Technology
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• v.40 no.2
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• pp.228-233
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• 2008

Ultraviolet sterilizers (UVS) are widely used in restaurants, cafeterias and catering businesses in Korea. The proper application of UVS, however, is still questionable since no studies have clearly identified their efficacy and safety, while regulations and regulatory management systems are yet to be established. In the present study, the efficacy of UVS were investigated by measuring spatial UV intensity inside five commercially operated UVS. The operating safety parameters were also checked by measuring leaked UV intensity. The UV intensities were inversely proportional to distance from the UV lamp within 25 cm, and to the square of the distance exceeding 25 cm. The UV intensities in commercial UVS varied with the distance from UV lamp and the incident angle, highlighting efficacy and stability concerns. Notable leakage was detected through the door gaps of a studied UVS, which also brought about safety concerns. Allowable working distances for the UV leaking UVS were suggested based on international standards.

• Journal of Sensor Science and Technology
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• v.30 no.4
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• pp.250-254
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• 2021

A highly sensitive and selective non-dispersive infrared (NDIR) carbon dioxide gas sensor requires achieving high transmittance and narrow full width at half maximum (FWHM), which depends on the interface of the optical filter for precise measurement of carbon dioxide concentration. This paper presents the design, simulation, and fabrication of a Fabry-Perot filter based on a distributed Bragg reflector (DBR) for a low-cost NDIR carbon dioxide sensor. The Fabry-Perot filter consists of upper and lower DBR pairs, which comprise multilayered stacks of alternating high- and low-index thin films, and a cavity layer for the resonance of incident light. As the number of DBR pairs inside the reflector increases, the FWHM of the transmitted light becomes narrower, but the transmittance of light decreases substantially. Therefore, it is essential to analyze the relationship between the FWHM and transmittance according to the number of DBR pairs. The DBR is made of silicon and silicon dioxide by RF magnetron sputtering on a glass wafer. After the optimal conditions based on simulation results were realized, the DBR exhibited a light transmittance of 38.5% at 4.26 ㎛ and an FWHM of 158 nm. The improved results substantiate the advantages of the low-cost and minimized process compared to expensive commercial filters.

• Journal of the Korean Society of Safety
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• v.37 no.1
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• pp.49-54
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• 2022

In Korea, companies which have work-related musculoskeletal burden works should have conducted legal risk assessments every three years from 2004 onwards. However, due to problems with the legal definition of work-related musculoskeletal burden works, some companies may have been exempted from the risk assessment even though their workers still experience work-related musculoskeletal pain. For example, the manufacturing process used by a particular semiconductor manufacturing company involved a great deal of legal musculoskeletal bueden works. However, this company eliminated the musculoskeletal burden works by continuously introducing automated processes, and finally, in 2016, all work which was legally defined as musculoskeletal burden work were removed from the company's manufacturing process. Nevertheless, in a 2016 survey, 9.6% of the company's workers still complained of musculoskeletal pain, and in a 2019 survey this proportion actually increased to 15.7%. This incident demonstrates the limitations and problems of the current legal risk assessment of work-related musculoskeletal burden work. Therefore, this study proposes two improvements to solve these problems. Firstly, it is necessary to broaden the current legal definition of work-related musculoskeletal burden works. For example, vibration risk factors and push/pull tasks that are currently missing from the definition should be included. Secondly, it is proposed that a survey on musculoskeletal pain should be conducted for all workers, regardless of whether they are engaged in musculoskeletal burden works. The results of this study could be used to improve the legal risk assessment of work-related musculoskeletal burden works.

• Journal of the Korea Society of Computer and Information
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• v.26 no.7
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• pp.65-73
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• 2021

The purpose of this study is to cornpare the differences in clinical competence, knowledge of patient safety management and confidence of patient safety management according to the clinical practice experience of nursing students, Of the 73 nursing students who experienced clinical practice and 35 nursing students who did not experience, a total of 108 students in the third grade were analyzed, In the results of this study, clinical competence(t=.88, p=.377) knowledge of patient safety management(t=-.29, p=.773), and confidence of patient safety management(t=1.11, p=.267) the difference between was not statistically significant in the two groups. In the two groups, the score of the sub-area according to each variable is the lowest. First, the sub-area of the nursing process a lowest score in clinical competence, and the second, the sub-area of measuring knowledge about concept of near miss was the Knowledge of patient safety management. The score was the lowest in, and thirdly, the sub-area of writing an incident report when an error occurred had the lowest score in confidence of patient safety management. Therefore, in order to improve the quality of clinical competence of nursing students, it is necessary to develop a strategic educational guideline to improve the clinical practice education environment, to improve patient safety management capabilities and to cultivate correct attitudes toward patient safety management.

• Proceedings of KOSOMES biannual meeting
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• 2009.06a
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• pp.9-15
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• 2009

On-Scene Commander's quickly discernment is very important in Catastrophic Oil Spill. The Korea carring out multiagency to catastrophic oil spill. but It cannot communication to other agency and happened to operation empty and duplications. The United State enforced Incident Command System/Unified Command (ICS/US) on National Incident Management System in 2008. The Korea Government must be preparation Unified Command System include Non-Government and an oil refining company.

• Wind and Structures
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• v.30 no.2
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• pp.181-198
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• 2020

In the traditional buffeting response analysis method, the spanwise incomplete correlation of buffeting forces is always assumed to be same as that of the incident wind turbulence and the action of the signature turbulence is ignored. In this paper, three typical bridge decks usually adopted in the real bridge engineering, a single flat box deck, a central slotted box deck and a two-separated paralleled box deck, were employed as the investigated objects. The wind induced pressure on these bridge decks were measured via a series of wind tunnel pressure tests of the sectional models. The influences of the wind speed in the tests, the angle of attack, the turbulence intensity and the characteristic distance were taken into account and discussed. The spanwise root coherence of buffeting forces was also compared with that of the incidence turbulence. The signature turbulence effect on the spanwise root coherence function was decomposed and explained by a new empirical method with a double-variable model. Finally, the formula of a sum of rational fractions that accounted for the signature turbulence effect was proposed in order to fit the results of the spanwise root coherence function. The results show that, the spanwise root coherence of the drag force agrees with that of incidence turbulence in some range of the reduced frequency but disagree in the mostly reduced frequency. The spanwise root coherence of the lift force and the torsional moment is much larger than that of the incidence turbulence. The influences of the wind speed and the angle of attack are slight, and they can be ignored in the wind tunnel test. The spanwise coherence function often involves several narrow peaks due to the signature turbulence effect in the high reduced frequency zone. The spanwise coherence function is related to the spanwise separation distance and the spanwise integral length scales, and the signature turbulence effect is related to the deck-width-related reduced frequency.