• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.8-15
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• 2007

Freeway corridors consist of urban freeways and parallel arterials that drivers can use alternatively. Ramp metering in freeways and signal control in arterials are contemporary traffic control methods that have been developed and applied in order to improve traffic conditions of freeway corridors. However, most of the existing studies have focused on either optimal ramp metering in freeways, or progression signal strategies between arterial intersections. There have been no traffic control systems in Korea that integrates the freeway ramp metering and arterial signal control. The effective control strategies for freeway operations may cause negative effects on arterial traffic. On the other hand, traffic congestion and bottleneck phenomenon of arterials due to the increasing peak-hour travel demand and ineffective signal operation may generate an accessibility problem to freeway ramps. Thus, the main function of the freeway which is the through-traffic process has not been successful. The purpose of this study is to develop an integrated control model that connects freeway ramp metering systems and signal control systems in arterial intersections. And Optimization of integrated control model which consists of ramp metering and signal control is another purpose. The design of experiment, neural network, and simulated annealing are used for optimization.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.131-140
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• 1999

Today freeway is experiencing a severe congestion with incoming or outgoing traffic through freeway ramps during the peak periods. Thus, the objectives of this study is to identify the traffic characteristics, analyze the relationships between the traffic characteristics and finally construct the delay predictive models on the ramp junctions of freeway with 70mph speed limit. From the traffic analyses, and model constructions and verifications for delay prediction on the ramp junctions of freeway, the following results were obtained: ⅰ) Traffic flow showed a big difference depending on the time periods. Especially, more traffic flows were concentrated on the freeway junctions in the morning peak period when compared with the afternoon peak period. ⅱ) The occupancy also showed a big difference depending on the time periods, and the downstream occupancy(Od) was especially shown to have a higher explanatory power for the delay predictive model construction on the ramp junction of freeway. ⅲ) The speed-occupancy curve showed a remarkable shift based on the occupancies observed ; Od < 9% and Od$\geq$9%. Especially, volume and occupancy were shown to be highly explanatory for delay prediction on the ramp junctions of freeway under Od$\geq$9%, but lowly for delay predicion on the ramp junctions of freeway under Od<9%. Rather, the driver characteristics or transportation conditions around the freeway were through to be a little higher explanatory for the delay perdiction under Od<9%. ⅳ) Integrated delay predictive models showed a higher explanatory power in the morning peak period, but a lower explanatory power in the non-peak periods.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.29-40
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• 2008

Although a good understanding of the relationship between highway traffic accidents and highway geometric features is fundamental in highway design and safety, the relationship is not well understood quantitatively. The overall goal of this paper is to formulate a reliable statistical model fitting to historical highway accident data. The model can be used to estimate the effect of road design elements on safety for the practical purposes of highway design applications. En route to achieving this goal, a number of specific research objectives were accomplished: investigate the major design elements affecting highway safety; review the existing modeling approaches in order to assess the relationship between safety and highway design features; and formulate a statistical model fitting to the accident data in order to estimate the interchange ramp junction accident frequency of rural highways.

• PNF and Movement
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• v.16 no.3
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• pp.415-424
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• 2018

Purpose: This study aimed to determine the effects of various wheelchair handling directions on the upper limb muscle activities of wheelchair attendants while climbing a ramp. Methods: For the study participants, healthy males over 20 years of age were chosen, and the order of the direction of wheelchair handle grip was determined using a randomized method. The handling directions for pushing the wheelchair up a ramp included a general grip with ulnar deviation, a medial grip with wrist pronation, and a neutral grip with a neutral wrist. The muscle activities in the participants' upper limbs were measured using surface electromyography. For statistical data processing, SPSS 18.0 was used to perform repeated measures ANOVA in order to compare the muscle activity among the intervention groups. A contrast test was also conducted among the participants. The significance level (${\alpha}$) was set to 0.05. Results: There was a significant difference between groups using a general grip and a medial grip in the biceps brachii, triceps brachii, and flexor carpi radialis muscles (p<0.05). There was also a significant difference between using a general grip and a neutral grip in the biceps brachii and flexor carpi radialis muscles (p<0.05), and there was a significant difference between using a medial grip and a neutral grip in the biceps brachii and extensor carpi radialis brevis muscles (p<0.05). Conclusion: In this study, the wheelchair assistants' wrist muscle activity was the lowest with a neutral grip while ascending a ramp. Accordingly, this study proposes that wheelchair assistants push wheelchairs up ramps with a neutral grip.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.4
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• pp.651-656
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• 2019

This paper is a study on the structure system and implementation of cantilever actuator for decontamination. There are many kinds of exterior materials that attach to the exterior walls of a building. Glass, in particular, can be contaminated in a short period of time due to external exposure. The pollutants like this damage the appearance of a building. It can also cause health problems for users, and dust attached to solar panels creates problems that greatly reduce the power generation of solar panels. In order to remove such contaminants, professional workers usually remove contaminants attached to the outer walls. However, even with stability, accidents are often caused by a number of unexpected variables that occur in the field. Thus, to overcome these shortcomings, the cantilever actuator structure system was proposed. The system was designed through research. Then, we made a cantilever actuator and checked its operability. Finally, the effectiveness of the cantilever actuator was reviewed.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.36 no.5
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• pp.41-51
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• 2020

As there are the elderly who have difficulty in evacuating themselves, it is necessary to develop architectural and institutional planning for nursing homes that can minimize disaster damage. The purpose of this study was to suggest the improvement plan by grasping the current status of nursing homes on planning aspects such as floor plan type, spatial layout, and evacuation route through 14 case studies in Cheongju city in terms of disaster safety. The results of this study were as follows; the most common plan type was the grouped-corridor type difficulty in securing evacuation routes. The circulation corridor type is need to be considered because it is possible not only to secure evacuation and nursing routes, but also to create a hanging around corridor for the elderly with dementia. Second, if there is a risk of flooding due to the location, the living room should be placed on the 2nd floor or more. In particular, a kitchen should be placed not adjacent to the entrance and the vertical evacuation route. Third, the horizontal evacuation route should be arranged differently depending on the floor plan type. For vertical evacuation routes, it is necessary to install outdoor stairs or ramps considering the evacuation characteristics of the elderly. In addition, the institutional aspects should be considered to ensure the safety of disasters.

• PNF and Movement
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• v.19 no.2
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• pp.261-267
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• 2021

Purpose: This study aimed to investigate changes in gait variables depending on whether a task was performed using a smartphone while walking on a ramp. Methods: The participants of this study were 41 college students attending U University located in Gyeongju City, Gyeongsangbuk-do. In this study, gait variables were measured during ramp gait while using a smartphone to perform a task and during ramp gait without performing such tasks. In other words, four walking conditions were used: 1) walking up a ramp, 2) walking up a ramp while using a smartphone to perform a task, 3) walking down a ramp, and 4) walking down a ramp while using a smart phone to perform a task. Gait variables were measured using a gait analysis tool (Legsys; BioSensics, USA), and stride time, stride length, stride velocity, cadence, and double support were analyzed. The order of measurements was randomized to control for order effects due to repeated measurements. Results: The comparative analysis of gait variables according to the presence or absence of smartphone use during ramp gait showed that there were significant differences in stride time, stride length, and stride velocity during both ramp ascent and ramp descent (p < 0.05). In both ramp ascent and ramp descent, stride time increased when walking using a smartphone, compared to when walking without using a smartphone (p < 0.05). However, in both ramp ascent and ramp descent, stride length and stride velocity were decreased when walking using a smartphone compared to when walking without using a smartphone (p < 0.05). Conclusion: The study results showed that the use of a smartphone during walking can affect safety. Therefore, it is necessary to improve the awareness of risks associated with walking while using a smartphone, and further research needs to be conducted in various environments and with different ramps.

• The Journal of Engineering Geology
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• v.31 no.4
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• pp.541-547
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• 2021

To assess the stability of a slope and the likelihood of its loss or collapse requires information about the ground, such as the composition of the stratum and its mechanical characteristics. This information is generally gathered through standard penetration testing (SPT) and cone penetration testing. SPT is not widely used due to problems with accessing slopes, most of which are steep and without ramps. A drop cone penetrometer, a portable device that can make up for these shortcomings, can be used in a limited way in some circumstances. Therefore, we developed a portable drilling machine and a small dynamic cone penetration test module that can easily access a slope site and perform SPT. The correlation of the developed system's results with those from SPT was analyzed. Analysis of the correlation between the energy shear rate passing to the load during the different test types established that the energy shear rate is reflected in the test result. The correlation between corrected dynamic cone penetration testing and corrected SPT was N_d' = 3.13 N'.

• Geomechanics and Engineering
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• v.31 no.6
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• pp.599-614
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• 2022

One of the methods of stabilizing retaining walls, embankments, and deep excavations is the implementation of plate anchors (like the Geolock wall anchor systems). Back-to-back Mechanically Stabilized Earth (BBMSE) walls are common stabilized earth structures that can be used for bridge ramps. But so far, the analysis of the interactive behavior of two back-to-back anchored walls (BBAW) by double-plates anchors (constructed closely from each other and subjected to the limited-breadth vertical loading) including interference of their failure and sliding surfaces has not been the subject of comprehensive studies. Indeed, in this compound system, the interaction of sliding wedges of these two back-to-back walls considering the shear failure wedge of the foundation, significantly impresses on the foundation bearing capacity, adjacent walls displacements and deformations, and their stability. In this study, the effect of horizontal distance between two walls (W), breadth of loading plate (B), and position of vertical loading was investigated experimentally. In addition, the comparison of using single and equivalent double-plate anchors was evaluated. The loading plate bearing capacity and displacements, and deformations of BBAW were measured and the results are presented. To evaluate the shape, form, and how the critical failure surfaces of the soil behind the walls and beneath the foundation intersect with one another, the Particle Image Velocimetry (PIV) technique was applied. The experimental tests results showed that in this composite system (two adjacent-loaded BBAW) the effective distance of walls is about W = 2.5*H (H: height of walls) and the foundation effective breadth is about B = H, concerning foundation bearing capacity, walls horizontal displacements and their deformations. For more amounts of W and B, the foundation and walls can be designed and analyzed individually. Besides, in this compound system, the foundation bearing capacity is an exponential function of the System Geometry Variable (SGV) whereas walls displacements are a quadratic function of it. Finally, as an important achievement, doubling the plates of anchors can facilitate using concrete walls, which have limitations in tolerating curvature.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5D
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• pp.467-476
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• 2010

Travel delay (TD) denotes a time difference between the running time of vehicle with a normal speed and the travel time of vehicle with a reduced speed for traversing the same segment of roadway, and is sometimes used as a measure of time delayed in the junction or bottleneck areas of roadway. Urban freeways in the foreign countries are often suffering from traffic delay within the entrance and exit ramp junction influence areas, as a freeway with the speed limit of 80 km/h or higher only during the rush hours, but those in our country are especially experiencing severe traffic delay on the mainline segments as well as within the entrance and exit ramp junction influence areas, as a freeway with the speed limit of 80 km/h or less regardless of the rush hours. So, the purpose in this study is to develop the models that could predict the travel delay within the ramp junction influence areas of urban freeway having the geographical features which differ from the expressway, and also examine the validity of the travel delay predictive models developed.