• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.4
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• pp.307-319
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• 2010

As we learned in Daegu subway fire accident, fire in the railway tunnel is prone to develop to large disaster due to the limitation of smoke control and smoke exhaust. In railway tunnel, in order to ensure fire safety, fire prevention and fighting systems are installed by quantitative risk assessment results. Therefore, in this research, developed the program to establish quantitative risk assessment and suggested quantitative safety assessment method including fire scenarios in railway tunnel, fire and evacuation analysis model, fatality estimate model and societal risk criteria. Moreover, this method applys to plan preventing disaster for Honam high speed railway tunnel. As results, we presented the proper distance of escape route and societal risk criteria.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.397-402
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• 2013

In super-tall building construction projects, schedule risk factors which vertically change and are not found in the low and middle-rise building construction influence duration of a project by vertical attribute; and it makes hard to estimate activity or overall duration of a construction project. However, the existing duration estimating methods, that are based on quantity and productivity assuming activities of the same work item have the same risk and duration regardless of operation space, are not able to consider the schedule risk factors which change by the altitude of operation space. Therefore, in order to advance accuracy of duration estimation of super-tall building projects, the degree of changes of these risk factors according to altitude should be analyzed and incorporated into a duration estimating method. This research proposes a simulation model using Monte Carlo method for estimating activity duration incorporating schedule risk factors by weather conditions in a super-tall building. The research process is as follows. Firstly, the schedule risk factors in super-tall building are identified through literature and expert reviews, and occurrence of non-working days at high altitude by weather condition is identified as one of the critical schedule risk factors. Secondly, a calculating method of the vertical distributions of the weather factors such as temperature and wind speed is analyzed through literature reviews. Then, a probability distribution of the weather factors is developed using the weather database of the past decade. Thirdly, a simulation model and algorithms for estimating non-working days and duration of each activity is developed using Monte-Carlo method. Finally, sensitivity analysis and a case study are carried out for the validation of the proposed model.

• Journal of Korean Society of Transportation
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• v.35 no.6
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• pp.499-510
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• 2017

Traffic accident fatalities in Korea in 2016 was 4,292 and 1,732 cases were deaths of elderly people. In spite of this, the researches on behaviors of the elderly when crossing roads, are rather limited. The purpose of this study is to investigate and analyze road crossing behavior characteristics of the elderly, when crossing roads, especially focusing on the characteristics of pedestrians and vehicles. Cross-sectional data was collected from six different sites in two regions and the following results was identified. First, at road crossings, 528 cases(84.3%) out of 626 conflict situations of the elderly and 303 cases(63.3%) out of 478 conflict situations of the non-elderly pedestrians were found to be dangerous, respectively. The elderly tend to face a statistically significant risk of 3.11 times higher than that of non-elderly people. Second, 519 cases(82.9%) of jaywalking occurred in 626 conflict cases of the elderly and 375 cases(78.5%) of jaywalking in 478 conflict events of non-elderly persons, which indicates the elderly's 1.34 times higher trend compared with the non-elderly's. Third, the pedestrian safety margin (PSM) analysis showed that the PSM of the elderly and the non-elderly were 3.33 seconds and 4.04 seconds respectively, which is 17.5% high. Fourth, the difference in pedestrian safety interval was examined by dividing the speed of approaching vehicle into less than 30km/h, above 30km/h and less than 50km/h, and over 50km/h. There was no significant difference between the PSM of coming vehicles with the speed less than 30km/h and the PSM of approaching with the speed 30km/h~50km/h, but the conflicts with vehicle of the speed above 50km/h show significantly lower PSM than with vehicle speed of 30km/h~50km/h. Finally, when the risk threshold is set to less than 2.5 seconds, the analysis shows that older pedestrians tend to cross roads dangerously 1.59~2.53 times than younger pedestrians. The results set forth here can be used as a basis for constructing the elderly safety measures at present and a potential basis for autonomous vehicle safety application in the future for solving the issue of the difference in crossing behavior between elderly and non-elderly pedestrians.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.11
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• pp.411-418
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• 2022

Incorrectly loaded containers can easily knock down by strong winds. Container collapse accidents can lead to material damage and paralysis of the port system. In this paper, We propose a deep learning-based container loading state and accident risk detection technique. Using Darknet-based YOLO, the container load status identifies in real-time through corner casting on the top and bottom of the container, and the risk of accidents notifies the manager. We present criteria for classifying container alignment states and select efficient learning algorithms based on inference speed, classification accuracy, detection accuracy, and FPS in real embedded devices in the same environment. The study found that YOLOv4 had a weaker inference speed and performance of FPS than YOLOv3, but showed strong performance in classification accuracy and detection accuracy.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.195-201
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• 2008

Damage from typhoon disaster can be mitigated by grasping and dealing with the damage promptly for the regions in typhoon track. What is this work, a technique to analyzed dangerousness of typhoon should be presupposed. This study estimated 10 m level wind speed using 700 hPa wind by typhoon, referring to GPS dropwindsonde study of Franklin(2003). For 700 hPa wind, 30 km resolution data of Regional Data Assimilation Prediction System(RDAPS) were used. For roughness length in estimating wind of 10 m level, landuse data of USGS are employed. For 10 m level wind speed of Typhoon Rusa in 2002, we sampled AWS site of $7.4{\sim}30km$ distant from typhoon center and compare them with observational data. The results show that the 10 m level wind speed is the estimation of maximum wind speed which can appear in surface by typhoon and it cannot be compared with general hourly observational data. Wind load on domestic buildings relies on probability distributions of extreme wind speed. Hence, calculated 10 m level wind speed is useful for estimating the damage structure from typhoon.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.983-988
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• 2009

When the railway vehicle passing through curves & transitions, the running speed must improve by proposing the practical standard about maximum running possibility speed of each section on existing line considering running safety. In this paper, when the railway vehicle passing through curves of actual track conditions (Namsunghyun-Chungdo up & down lines), the effect that has influence on running safety is examined to devise the high speed of vehicle which passing through curves which risk of derailment is high. The running safety analysis is performed that running speed by curve radius improves 5-20% compared with existing speed under actual track conditions. In result of the running safety analysis, in case the speed condition is fewer than 15% compared with existing speed, the derailment coefficient and unloading ratio are within acceptable level. so we could confirm possibility of speed improvement on the whole Namsunghyun-Chungdo up & down lines.

• Physical Therapy Korea
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• v.10 no.1
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• pp.77-95
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• 2003

Many factors affect foot and ankle biomechanics during walking, including gait speed and anthropometric characteristics. However, speed has not been taken into account in foot kinematics and kinetics during walking. This study examined the effect of walking speed on foot joint motion and peak plantar pressure during the walking phase. Eighty healthy subjects (40 men, 40 women) were recruited. Maximal dorsiflexion and excursion were measured at the first metatarsophalangeal joints during walking phase at three different cadences (80, 100, and 120 step/min) using a three dimensional motion analysis system (CMS70P). At the same time, peak plantar pressure was investigated using pressure distribution platforms (MatScan system) under the hallux heads of the first, second, and third metatarsal bones and heel. Maximal dorsiflexion and excursion and excursion at the ankle joint decreased significantly with increasing walking speed. Peak plantar pressure increased significantly under the heads of the first of the first, second, and third metatarsal bones, and heel with increasing walking speed: three was no change under the hallux. There were no significant changes in maximal dorsiflexion or excursion at the first metatarsophalangeal joint. The results show that walking speed should be considered when comparing gait parameters. The results also suggest that slow walking speeds may decrease forefoot peak plantar pressure in patients with peripheral neuropathy who have a high risk of skin breakdown under the forefoot.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3D
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• pp.403-412
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• 2011

On a curve radius, there is speed deviation because a driver who is on the curve radius can have visual distortion. The curve radius can be more dangerous than a straight radius by many reasons. Especially, visibility paralysis of delineator that is because of night and bad weather. Can pervert the information about curve sections, it threatens safety. More over accident risk is increased by influence to travel speed. Therefore, it needs to build and control delineators for driver's visibility. Therefore, this study focus on finding the two types of delineator(the retro-reflection and inside-lighting delineator) by insight-surveying and the operating speed are compared by survey and operating speed. Finally, inside-lighting delineator will be selected in terms of safety at the curve sections. The inside-lighting delineator was more effective than the retro-reflection delineator on visibility, the necessity of reduction of speed and will reduce the hazard at curve sections. Also, the study analyzes safety is guaranteed by the slight reduction of speed when the driver enters a curve radius with inside-lighting delineator. As a result, the inside-lighting delineator can give the information about horizontal and vertical profile effectively, so it can reduce the accident risk. And it can use to improve traffic safety on curve radius.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.685-688
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• 2017

Using ALOHA and PHAST Program, it was modeled assuming the leakage accident scenarios of chlorine which is designated as accident preparation chemical in chemical control act. End-point distances corresponding to ERPG-2 concentrations were calculated while varying annual mean temperature, wind speed, humidity, and atmospheric stability. The calculated endpoint distance values were compared and the correlation with each meteorological factor was analyzed. And we also investigated strengths and weaknesses of ALOHA and PHAST. The results show that ALOHA has little or no correlation with annual average temperature, humidity and it has a large correlation with wind speed and atmospheric stability. In the case of PHAST, the end-point distances were correlated with all the meteorological factors such as average annual temperature, wind speed, humidity, and atmospheric stability, Among them, the effect of atmospheric stability were the largest.

• Journal of Navigation and Port Research
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• v.29 no.7
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• pp.641-646
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• 2005

In cargo-working, it unavoidably happens that the quay crane slip along the rail and the container move from side to side. Especially, they involve a lot of risk in bad weather. The rail clamp is a mooring device to prevent that the quay crane slips along the rail due to bad weather or the wind blast while the quay crane do the cargo-working And it will play a greater role in port container terminal integration and automation To design the wedge type rail clamp, it is very important to determine the wedge angle. In this study, we expect that the design wind speed of the quay crane will change over 16m/s. Assuming that the design wind speed is 40m/s, we determined the proper wedge angle of the wedge type rail clamp for the 50ton class quay crane.