• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.2
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• pp.48-61
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• 2020

The objective of this study is to estimate traffic capacity based on the heavy-vehicle ratio in a two-lane freeway work zone where one lane is blocked by construction. For this, closed circuit television (CCTV) video data of the freeway work zone was collected, and the congestion at an upstream point was observed. The traffic volume at a downstream point was analyzed after a bottleneck was created by the blockage due to the upstream congestion. A distribution model was estimated using observed-time headway, and the road capacity was analyzed using a goodness-of-fit test. Through this process, the general capacity and an equation for capacity based on the heavy-vehicle ratio passing through the work zone were presented. Capacity was estimated to be 1,181~1,422 passenger cars per hour per lane (pcphpl) at Yeongdong, and 1,475~1,589pcphpl at Jungbu Naeryuk. As the ratio of heavy vehicles increased, capacity gradually decreased. These findings can contribute to the proper capacity estimation and efficient traffic operation and management for two-lane freeway work zones that block one lane due to a work zone.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.381-382
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• 2023

Frequent accidents occur when workers at construction sites leave the safety zone, and particularly in the past 5 years, 9 fatal accidents occurred at the Korea Railroad Corporation due to train accidents on other tracks during track work. With the Severe Accident Punishment Act taking effect in January 2022, it is a priority to secure a safe work environment for workers at industrial (construction) sites. Therefore, there is a need to manage workers' departure from the safety zone (construction zone) and to facilitate communication within the construction zone. In this study, a mobile edge computing CCTV system is proposed that uses geofencing to determine whether workers are working in the danger zone, which can judge and respond in real-time to the ever-changing field environment. The proposed system is mobile and flexible, rather than server-based fixed CCTV. However, since it is designed mainly based on images, it has limitations in recognition rate depending on the environment such as distance, viewing angle, and illumination. As a way to compensate for this, it is required to develop more reliable equipment by combining technologies such as LiDAR and Radar.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2002.04a
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• pp.105-110
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• 2002

This study aims for the research of the local circulation in a kitchen to minimize the kitchen work load and to produce a more efficient kitchen system. This study analized the real behavior and circulation in the kitchen area and this focused on the kitchen of the working women in a dual-income family. Through the analisis, this study raised an idea that the work in the kitchen area is not in sequence, but random while the tradition idea of the kitchen system is arranged by cooking programe. Therefore, this became a reason to increase the kitchen work load ratter than the layout of the kitchen system, the cooking style and menu affected on the more kitchen load. To reduce the kitchen work load, the designeer should shorten the circulation in the kitchen area. And this is possible through the decrease distance between the sink and a kiting zone and through the wide kitchen table which is between the sink and a kiting zone.

• Journal of Korean Society of Transportation
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• v.34 no.3
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• pp.263-277
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• 2016

Traffic safety in freeway work zones is of keen interest since both crash frequency and severity are much higher than those in general freeway sections. The lane closure in work zones results in greater work load of drivers due to compulsory lane changes and speed reduction. Therefore, traffic merging control is an effective countermeasure for enhancing work zone safety. This study proposed an integrated framework based on driving and traffic simulations to evaluate traffic merging control methods in terms of traffic safety. In addition to the conventional merging method using the taper, joint merge and chicane-type merge were evaluated by the proposed methodology. Chicane-type merge outperformed other methods under level of service (LOS) A and B. On the other hand, it was identified that joint merge showed the best safety performance under LOS C traffic conditions.

• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.278-291
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• 2017

Effective installation and operations of traffic safety signs in the advance warning area is of considerable interest for safer traffic management at freeway work zones. This study evaluated the feasibility of traffic safety sign installation based on a driving simulation experiment to take drivers' responsive characteristics into consideration. Both the compliance rate for speed limit and a lane-changing safety index were used for evaluating a set of driving simulation scenarios. It was identified that providing speed limit signs to reduce speed in advance and afterward guiding lane-changing could lead to safer maneuvering of vehicles entering work zones. The outcomes of this study are expected to be useful for revising freeway work zone management policies toward crash prevention.

• Journal of Korean Society of Transportation
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• v.31 no.1
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• pp.77-86
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• 2013

This paper focuses on the development of analytical models for estimating the changes in saturation flow rates (SFR) at the stop-lines of a signalized intersection due to the existence of nearby work-zones, and thereby calculating the prevailing capacity values for specific lane groups. Major changes were incorporated in the logics of previous models and significant revisions have been made to secure the accuracy and simplicity. Furthermore, much attention was paid to model validation by making comparisons to both extensive simulation results and empirical data from various sites. It was found that SFRs are highly sensitive to the location of work-zones, the distance to each work-zone from the stop-line of a concerned approach, the number of lanes open and closed, and the effective green time. Using such geometric and operating conditions that constitute work-zone environment, the proposed models successfully estimated SFR values with a miniscule margin of error.

• Journal of Korean Society of Transportation
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• v.12 no.1
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• pp.43-54
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• 1994

The major concern of this paper is to investigate the properties of a stochastic equilibrium for each model system in terms of a consumer welfare measure. The primary assumption for this study is that a trip-maker would choose the trip from his origin zone which maximizes his personal welfare. This assumption, finally, leads to a singly constrained gravity model. The consumer welfare measure is derived from the concept of expected welfare of randomly sampled trip-makers. Each of the four different models considered in this paper is differentiated depending on the complexity of its model or the definition of its travel function. In this study, three different regions are chosen for the purpose of taking into account the effects of different zone-systems on the properties of a stochastic equilibrium : (i) Archerville region (5 zone) ; (ii) San Francisco Bay regions (30 zones) ; (iii) Houston, TX region (199 zones). It is concluded that almost identical, "global" consumer welfare values can be obtained in some cases of the gravity-type trip distribution models based on a stochastic equilibrium.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.601-607
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• 2017

Objective: A method to assess the risk level of agricultural works considering work posture and working time was suggested, and the method was applied to the major fruit crops. Background: It is not complete to analyze only work postures when assessing risk level of agricultural works. Method: $3{\times}3$ matrix was employed, in which the severity level was taken from the REBA method and exposure level was taken from the working time, using the criteria of caution zone/hazard zone. Results: Among the 5 major fruit crops(apple, pear, grape, peach, persimmon), the highest level of ergonomic risk was found in the apple and pear, while medium level was found in other 3 crops, mainly because the working time was less in the 3 crops. Conclusion: It was found that when assessing the overall ergonomic risk of agricultural works, work posture and working time should be considered at the same time. Application: The suggested method could be applied to other non-cyclic tasks.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.6
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• pp.84-91
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• 1999

The goal of this study is to analyse the stress and the strain occurring within the work piece at the fine-blanking process and hence to assume the size direction and a distribution chart of the shearing stress as the penetration of the punch is being increased trough the application of the FEM. For this analysis we introduced the piece-wise linear method in the non linear structural analysis program for large deformation sheet metal forming and we defined it as the problem of the non linear contact. Therefore we modeled the above problems as quadratic-nodded axi-symmetrical elements for the character-istics of the work piece. From the result of this analysis it was found that the shearing stress is a great deal occurred on the surface of the work piece during the beginning process of the punch penetration and it's effect is expected to influence importantly for the formation of burnish because the deeper is the penetration of the punch in the narrow clearance zone. the greater is the degree of the strain stress.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.04a
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• pp.35-41
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• 1995

Fracture Mechanics does work for concrete, provided that a finite nonlinear zone at fracture front is being considered. The development of model for fracture process zone is most important to describe fracture phenomena in concrete. The fracture process zone is a region ahead of a traction-free crack, in which two major mechanisms, microcracking and bridging, play important rules. The toughness due to bridging is dominant compared to toughness induced by microcracking, so that the bridging is dominant mechanism governing the fracture process of concrete. In this paper the bridging zone, which is a part of extended macrocrack with stresses transmitted by aggregates in concrete, is model led by a Dugdale-Barenblatt type model with linear tension-softening curve. Two finite element techniques are shown for the model of fracture process zone in concrete.