• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.115-122
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• 2010

The importance of the life cycle cost (LCC) analysis for bridges has been recognized over the last decade. However, it is difficult to predict LCC precisely since the costs occurring throughout the service life of the bridge depend on various parameters such as design, construction, maintenance, and environmental conditions. This paper presents a methodology for the optimal life cycle cost design of a bridge. Total LCC for the service life is calculated as the sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, user cost, and disposal cost. The optimization method is applied to design of a bridge structure with minimal cost, in which the objective function is set to LCC and constraints are formulated on the basis of Korean Bridge Design Code. Initial cost is calculated based on standard costs of the Korea Construction Price Index and damage cost on damage probabilities to consider the uncertainty of load and resistance. Repair and rehabilitation cost is determined using load carrying capacity curves and user cost includes traffic operation costs and time delay costs. The optimal life cycle cost design of a bridge is performed and the effects of parameters are investigated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.483-491
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• 2021

The identification of regional collision risks in water areas is significant for the safety of navigation. This paper introduces a new method of collision risk assessment that incorporates a clustering method based on the distance factor - hierarchical clustering - and uses real-time data in case of several surrounding vessels, group methodology and preliminary assessment to classify vessels and evaluate the basis of collision risk evaluation (called HCAAP processing). The vessels are clustered using the hierarchical program to obtain clusters of encounter vessels and are combined with the preliminary assessment to filter relatively safe vessels. Subsequently, the distance at the closest point of approach (DCPA) and time to the closest point of approach (TCPA) between encounter vessels within each cluster are calculated to obtain the relation and comparison with the collision risk index (CRI). The mathematical relationship of CRI for each cluster of encounter vessels with DCPA and TCPA is constructed using a negative exponential function. Operators can easily evaluate the safety of all vessels navigating in the defined area using the calculated CRI. Therefore, this framework can improve the safety and security of vessel traffic transportation and reduce the loss of life and property. To illustrate the effectiveness of the framework proposed, an experimental case study was conducted within the coastal waters of Mokpo, Korea. The results demonstrated that the framework was effective and efficient in detecting and ranking collision risk indexes between encounter vessels within each cluster, which allowed an automatic risk prioritization of encounter vessels for further investigation by operators.

• Journal of Digital Convergence
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• v.16 no.5
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• pp.43-53
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• 2018

Recently, public service for the improvement of quality of life and life support such as safety, aging, disaster, welfare, housing, economy, urban environment, traffic etc are actively developed based on open public data, and the spread of the network and the necessity of everyday life, smartphones are playing a role in providing public services. Currently, the development of science is changing the life expectancy of human beings and changing into social structure in which aged people become bigger due to various social conditions and low fertility and aging problems. However, the elderly who do not have easy access to information are very uncomfortable in dealing with mobile devices with very low accessibility and utilization of public services provided by mobile phones. Therefore, this study recategorizes the condition of the elderly presented in the previous study and identifies the problem through case analysis provided for the elderly. Also, we summarize the hierarchy of the core items of the existing interface design and derive it as an improvement index of the public service design for the improvement of the information accessibility of the elderly, and propose a design method to improve the utilization of the public service provided through the mobile device.

• International Journal of Highway Engineering
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• v.14 no.3
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• pp.131-140
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• 2012

Lane markings such as edgelines, centerlines, and lines that delineate lanes generally provide drivers with the various information for safe driving. Drivers can easily recognize the lane markings through the color differences between the markings and road surfaces during the daytime. However, it is a bit difficult for drivers to perceive them during the nighttime due to the lack of artificial lights. Although the glass beads with the 1.5-refractive index have been used to improve the visibility of the lane markings during the nighttime, it is still difficult for drivers to recognize the lane markings properly, especially during the rainy nighttime, which may often lead to traffic accidents. To improve the retroreflectivity and visibility of the lane markings during the rainy nighttime, the high refractive beads with the 2.4-refractive index are essentially required, but they do not work appropriately during the dry nighttime. Thus, the mixed materials with the 1.5, 1.9, and 2.4-refractive beads should be considered for the satisfactory implementation of the lane markings. This study reveals the best mixing rates of the beads by conducting benefit-cost analysis under various weather conditions in Korea. The analysis results show that the lane markings with the 100% of the 2.4-refractive beads provide the highest visibility of lane markings regardless of the roadway conditions, but the benefit-cost (B/C) ratio of the bead mixture is merely 0.46. The best mixing rate of the beads, from the highest B/C ratio viewpoint, was identified as the mixture with a 80% of 1.5-refractive beads and a 20% of 2.4-refractive beads. Some limitations and future research agenda have also been discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.895-906
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• 2018

The improvement project for school zone in Korea is occurring mostly in kindergartens and elementary schools in which children are mainly active, and is being promoted as part of measures to prevent children's traffic accidents. However, since the study on the essential installation facilities and proper level of safety facilities for School zone is lacking, this study relatively evaluated the efficiency of safety facility installation using DEA (Data Envelope Analysis) and suggested improvement plan. We built the facilities and incident data for 28 school zones in Hwaseong City. Six major facilities (Raised intersection, Raised crosswalk, Protective fence, Skid Proof, Speed hump, Speed cameras) that have proven to be effective in the preceding research were analyzed as input factors. As a result of the analysis, only 12 out of 28 showed efficiency and 16 out of efficiency. Effective groups of school zones were found to have fewer installed Protective fences, Skid Proof, and Speed cameras installations than school zones classified as ineffective groups. Protective fences were found to be efficient even if only 47% of the total extension of the school zone was installed, and the number of slip prevention facilities was 8.7 per square km. The number of subjects to be compared is 28, so this study is limited to use as a relative efficiency evaluation index, and it can be grouped into nationwide units and efficiency evaluation can be done for each group.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.138-147
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• 2018

With the recent series of damage caused by earthquakes in Korea, such as Gyeongju and Pohang, we know that Korea is no longer a safe zone for earthquakes and that we need to be prepared for them. In addition, bridges built prior to the introduction of seismic design concepts remain without adequate seismic reinforcement measures, and earthquake reinforcement should be performed efficiently considering economic and structural safety. Preliminary assessment of seismic performance of existing bridges is divided into four seismic groups, taking into account seismicity, vulnerability and Impact, considering the magnitude of the existing bridge's seismic, and prioritization for further evaluation of seismic performance. In this study, unlike the existing anti-seismic reinforcement priority method, scores are calculated based on the seismic design criteria applied to bridges, importance coefficient of the bridge including the zone coefficient and the Importance, vulnerability index of the bridge including the soil condition and the elapsed years, detail coefficient of the bridge including the superstructure form, the span length, the width, the height, the design load, and the daily traffic volume. The calculated score items will be weighted and grouped according to the results. Using this, a simpler and more efficient algorithm was proposed to determine the priority of seismic reinforcement on a bridge.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.161-163
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• 2021

This urban centralization is expected to develop rapidly, with 75% of the population living in the city by 2035. Large cities are becoming unsustainable due to side effects such as environmental pollution, severe traffic jams, excessive energy depletion, and destruction of the natural ecosystem. In addition, the happiness index of citizens of large cities is also falling because of high crime rates and safety accidents, the work-life imbalance caused by inequality and polarization, and overly competitive education. To solve this problem, Smart City, an IT-based future city model, was born. The Korean government is also actively attempting to improve urban competitiveness and promote sustainable development through efficient construction and operation of smart cities as a national focus project. To support the effort, we review the basic directions and strategies of Sejong City's Smart City service infrastructure based on the comprehensive national land plan, Smart City plan, and Smart City strategy plan.

• Journal of Trauma and Injury
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• v.36 no.4
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• pp.385-392
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• 2023

Purpose: This study investigated the epidemiology, management, outcomes, and postoperative disabilities of degloving soft tissue injuries (DSTIs) treated at a tertiary care center in northern India. Methods: A prospective study of patients with DSTIs was conducted over 15 months. The type of degloving injury, the mechanism of injury, and any associated injuries were analyzed using the World Health Organization Disability Assessment Schedule (WHODAS) 2.0 along with the management, outcomes, and disabilities at a 3-month follow-up. Results: Among 75 patients with DSTIs, the average age was 27.5 years, 80.0% were male, and 76.0% had been injured in traffic accidents. The majority (93.3%) were open degloving injuries. Lower limbs were affected most often (62.7%), followed by upper limbs (32.0%). Fractures were the most commonly associated injuries (72.0%). Most patients required more than two procedures, including secondary debridement (41.3%), split skin grafting (80.0%), flap coverage (12.0%), or vacuum-assisted closure (24.0%), while five patients underwent conservative management for closed degloving injuries. Postoperative complications included surgical site infections (14.7%) and skin necrosis (10.7%). Two patients died due to septic shock and multiple organ dysfunction syndrome. The mean length of hospital stay was 11.5±8.1 days, with injuries affecting the lower limbs and perineum requiring longer hospital stays. The mean WHODAS 2.0 disability score at 3 months was 19. Most patients had mild disabilities. Time away from work depended largely upon the site and severity of the injury. Approximately 75% of patients resumed their previous job or study, 14% changed their job, and 8% stopped working completely due to residual disability. Conclusions: DSTIs are common injuries in trauma and management is challenging. Although open DSTI are clinically evident at secondary survey, closed degloving injuries may be missed in the primary survey, necessitating a high index of suspicion, thorough clinical examination, and protocol-based management. Primary preventive strategies (e.g., road safety protocols, preplacement training, and proper protective equipment in industries) are also needed to reduce the incidence of these injuries.

• Journal of Korean Society of Transportation
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• v.24 no.1 s.87
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• pp.19-28
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• 2006

To develop a crisis management for aviation safety, this study has defined crisis management includes risk management which is eliminates or lowers risks prior to accidents and emergency response after the accidents. This study takes a look at different kinds of crisis managements, risk managements and statistical methods of other nations and fields in order to develop a risk management model. Through surveys which have 102 risk factors that include air traffic control, maintenance and airport sectors, the weight of each risk factor was calculated and the probability was divided to develop a model for risk management. The risk management model of this study is conducted using four steps (risk management plan, risk factor identification, weight and probability analysis, decision making) and 4 standards of weight along with 5 standards of probability This study takes a look at Predictions through a quantitative method using a risk index for the risk management model An effective risk management model should have a wide and continuous collection of data and adopt various methods using this model. The crisis management could not be very effective only using a pre-active risk management. So it should also be conducted by using a pro-active response system to protect additional damage and to prevent accidents of the same nature. From the results, the most important points were the establishment of command and control accountabilities, and cooperation of related organizations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.3
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• pp.87-99
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• 1982

This study proposes a reliability based design criteria for the R.C. superstructures of highway bridges. Uncertainties associated with the resistance of T or rectangular sections are investigated, and a set of appropriate uncertainties associated with the bridge dead and traffic live loads are proposed by reflecting our level of practice. Major 2nd moment reliability analysis and design theories including both Cornell's MFOSM(Mean First Order 2nd Moment) Methods and Lind-Hasofer's AFOSM(Advanced First Order 2nd Moment) Methods are summarized and compared, and it has been found that Ellingwood's algorithm and an approximate log-normal type reliability formula are well suited for the proposed reliability study. A target reliability index (${\beta}_0=3.5$) is selected as an optimal value considering our practice based on the calibration with the current R.C. bridge design safety provisions. A set of load and resistance factors is derived by the proposed uncertainties and the methods corresponding to the target reliability. Furthermore, a set of nominal safety factors and allowable stresses are proposed for the current W.S.D. design provisions. It may be asserted that the proposed L.R.F.D. reliability based design criteria for the R.C. highway bridges may have to be incorporated into the current R.C. bridge design codes as a design provision corresponding to the U.S.D. provisions of the current R.C. design code.