• International Journal of Highway Engineering
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• v.14 no.6
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• pp.85-92
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• 2012

PURPOSES : Since expressways in South Korea are toll roads, many trumpet type interchanges exist, resulting in the installation of loop ramps very frequently. While the travel speed of the main lane is designed to be 100-110 km/h, the structure of a loop ramp is different and is designed for a minimum speed of 40 km/h. In fact, most of the actual travel speeds measured on the ramp exceed the designated speed, which has been a major problem in traffic safety. In this research, a type of pavement marking speed-reduction treatment called the "Peripheral Transverse Line" is installed on expressway loop ramps in order to study the change of driving speeds after the installation. METHODS : To verify statistically the change, this speed-reduction treatment has been installed on the Chungju interchange and the Yeoju junction. The driving speeds before the installation were compared with driving speeds both one month and five monthsafter the installation. RESULTS : As a result, the reductions of the average driving speeds after the treatment were statistically significant. More specifically, the average driving speeds of the Chungju interchange were reduced by 7.1-7.7 % for its tangent road section, and the speeds decreased by 8.5-9.5 % for its curve section. Similarly, in the Yeoju junction, an average speed reduction of 2.9-4.8 % for its tangent section was measured, along with 3.9% long-term speed reduction for its curve section. CONCLUSIONS : Since the pavement marking speed-reduction treatment has been partially proven to be effective from this research, we expect to expand this treatment and re-confirm the effect from a long-term perspective in the future.

• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.14-30
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• 2000

Hierarchically controlled sequence stratigraphic analysis shows that the Lower Ordovician mixed carbonate-siliciclastic Mungok Formation, Korea consists of three depositional sequences: T1, T2, and T3. Sequence boundaries are generally marked by abrupt transition from coarse-grained shallow-water carbonates to fine-grained deeper-water carbonates mixed with fine-grained siliciclastics, and show indication of subaerial exposure such as karstification. Within this sequence stratigraphic framework, facies characteristics indicate that the Mungok sequences were mostly deposited in subtidal ramp environments. High-frequency cycles consist of upward-shallowing facies successions. Cycles of shallow-water and basinal deposits are not represented well, probably due to cycle amalgamation. Cycle stacking patterns do not show a consistent thickness change that reflects a large-scale sea-level change due to unfilled accommodation space. The Mungok sequences show that many factors including relative sea-level change and topography are involved in controlling sequence development on carbonate ramps. The depositional setting evolved from the high-energy ramps in the sequences T1 and T2 into the low-energy ramp in the sequence T3. Topography is interpreted to have been responsible for the different energy regimes of the carbonate ramps in the Mungok sequences. The high ramp gradient in the sequences T1 and T2 seems to be caused by space-time-dissociated differential sedimentation resulting in spatially narrow distribution of sediment filling, which in turn may be related to high rate of relative sea-level change. In contrast, low ramp gradient was maintained in the sequence T3 during slow changes of relative sea level resulting in broad distribution of sediment filling.

• PNF and Movement
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• v.17 no.3
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• pp.379-389
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• 2019

Purpose: This study examined the effects of wheelchair handle directions on the trunk muscle activity of adult males when climbing ramps. It also evaluated the wheelchair attendant's physical discomfort during tasks. Methods: Healthy males aged over 20 years were chosen and the direction of wheelchair handle grip was randomly selected. The grips included a general grip with ulnar deviation, a medial grip with wrist pronation, and a neutral grip with a neutral wrist. The trunk muscle activity was measured using surface electromyography. Furthermore, the physical discomfort of wheelchair attendants was subjectively evaluated using the Borg CR-10 Scale, which rates the perceived exertion. In addition, the SPSS 18.0 program was used perform repeated measure ANOVA to compare muscle activity and subjective discomfort during the interventions. The contrast test was also conducted with a significance level (α) of 0.05. Results: There was significant difference between the general grip and the medial grip in the rhomboid major muscle and the lumbar erector spinae muscle (p<0.05). In addition, there was significant difference between the general grip and the neutral grip in the rhomboid major muscle and the lumbar erector spinae muscle (p<0.05). Further, there was significant difference between the general grip and the neutral grip in subjective discomfort (p<0.05). Conclusion: In this study, adult male trunk muscle activity and subjective discomfort were lowest when using the neutral grip while climbing ramps. Accordingly, we suggest that neutral grips will help improve the function of the musculoskeletal system and reduce the subjective discomfort by putting less strain on the trunk muscles and maximizing efficiency with less force.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.3
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• pp.59-66
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• 2019

In recent years, urban regeneration is focused on smart and pedestrian oriented development utilizing various mobility technology. The characteristics of walkways needs to reflect such development orientations. This research is the first step to find an adequate slope for ramp replacing stairs and shared by pedestrians, personal mobilities and powered wheelchairs. It aims to check if ramps on a recommended degree of angle by general guidelines are more preferred than stairs and find out what make difference of such preferences. Two surveys were conducted at $9^{\circ}$ and $9.6^{\circ}$ ramps coexisted with stairs at sequential and parallel location. The study on the survey result found that the general evaluation of $9^{\circ}$ ramp was better than $9.6^{\circ}$ ramp but $9^{\circ}$ ramp was not preferred than stairs while $9.6^{\circ}$ ramps was preferred. The difference of preferences was related to characteristics of stairs. The stair with shorter tread and riser next to $9^{\circ}$ ramp was evaluated much better than stairs next to $9.6^{\circ}$ ramp. Therefore the research concludes that $10.0^{\circ}$ which many guidelines recommend for the maximum slop of a ramp was not adequate for a ramp to replace stairs as a preferred means of vertical circulation. In addition the research found that the preference was sensitive to moving direction and gender especially in regards to comfort of stairs and safety of ramp. Most pedestrians chose a means of vertical circulation based on its comfort but pedestrian's evaluation of safety was most different based on moving direction.

• Journal of Korean Society of Transportation
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• v.24 no.7 s.93
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• pp.41-51
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• 2006

In this paper, a fundamental study on the characteristics of traffic accidents according to the alignment and traffic conditions on the ramp of freeway is addressed. The macro-and-micro scope analysis of characteristics about traffic accidents on the trumpet-IC ramps is conducted depending on the entering and exit ramp types under the various conditions of traffic volume and alignment And it is turned out that the conditions of alignment. such as radius, differences of curvatures, and main road grade, and traffic volume relate to the ramp accidents of trumpet IC according to ramp types, such as direction, semi-direction, and loop. Macroscopically, AR (Accident Rate) according to trumpet IC types, A and B, is analyzed nearly equal, but Number of accidents occurred in IC type B shows about 1.5 times higher than type A. And AR of exit ramps shows three times more than entrance ramps. Microscopically, ARs for each exit-ramp type, according to the increment of traffic volume, the difference of curvatures. and the first radius, exponentially decrease respectively. But relationships between AR and the second radius or exit ramp shows inverted U-shaped. AR according to main-road grade Peaks between -1.5% and -0.5%. It is expected that the developed models not only are employed to make design of trumpet-IC ramp more cost-efficiently and safely, but also contribute to making alternatives to the reduction of traffic accidents on trumpet IC ramps under the conditions of high traffic accident rate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1D
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• pp.65-72
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• 2011

When an expressway intersects another expressway, a unique connector needs to be designed between the two consecutive exit ramps. In such a case, it is important to design a connector such that there is enough distance for drivers to find their way safely. A current design manual in Korea prescribes the minimum length of the connector as 240 m. In this research, we have suggested a method for calculating the minimum length of a connector in order to check the feasibility of the currently prescribed length. For this purpose, we have attempted to determine the total perception-reaction time and lane-changing time required by a driver. For determining the driver's perception-reaction time, we have used the driver's decision time in addition to the conventional 2.5 s of perception-reaction time for stopping sight distances. We have considered both the design speed and the average travel speed for the calculation of the length. To evaluate the accuracy of the new method, we have chosen four sites on expressways for which relatively high accident rates were recorded. As a result, we could verify that the current limit (240 m) was sufficient for drivers to be able to change lanes in the given specific geometry. However, the prescribed limit should be revised in case the drivers' decision time is considered to be their perception-reaction time. All new approaches for calculating the ideal length of a connector have been carried out by taking into account the design speed as well as the average travel speed. Owing to the characteristics of the specific geometry for two consecutive exit ramps and the large difference between the design speed and the average travel speed in the objective areas, it is more realistic to use the proposed method by keeping the decision time equal to a driver's perception-reaction time, in order to determine the ideal distance that should be maintained between two consecutive exit ramps.

• Korean Journal of Veterinary Research
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• v.13 no.2
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• pp.103-109
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• 1973

By employing the vinylite and neoprene latex corrosion technique, the ramification and arrangement of A. renalis were observed in fifty adult dogs (100 kidneys). Obtained results were as follows: 1. In the dog a single renal artery arosed on each side from abdominal aorta in 99% and double renal arteries in 1%, a single bifurcated into the ramus dorsalis and ramps ventralis from which 2-6 segmental arteries originated. 2. The dorsal ventral planes of the kidney were divided separately into 3-6 vascular segments by the segmental artery into the parenchyma. Of them four segments were mostly frequent (in 73% of right kidney and 72% of left). 3. The ramifying method of the segmental artery from the ramus dorsalis et ventralis was divided 3 types and 12 kinds. 4. In 30 of 100 kidneys, either dorsal or ventral plane of a kidney was supplied from interlobar or segmental arteries belonging to the opposite ramps. In 29 of them, the dorsal plane was supplied from the ventral ramus. 5. Six right and 11 left kidneys had a common segment in the Extremitas cranialis of the kidney.

• The Journal of Korean Physical Therapy
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• v.24 no.4
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• pp.247-252
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• 2012

Purpose: The purpose of this study was to investigate the change of muscle activities during level walking, stairs and ramp climbing in hemiplegic patients. Methods: Eight hemiplegic patients were recruited and agreed to participate in this study. Muscle activity was measured by MP100 system (BIOPAC System Inc., Santa Barbara, CA, USA). Statistical analysis was used as a one-way repeated measure of ANOVA to know the difference according to the gait conditions (level walking, stairs and ramp ascending). Results: In the swing phase, muscle activity of rectus femoris muscle, with the side lower extremities affected, were generally significantly different in the stair and ramp ascending. In addition, biceps femoris muscle with unaffected side lower extremity was generally significantly different in the ramp ascending. In the swing phase, muscle activity of tibialis anterior muscle with unaffected side lower extremities was generally showed a significant difference in the ramp ascending. In the stance phase, climbing stairs and ramps showed an increase in the muscle activities. Further, climbing the stairs increased muscle activities of the gastrocnemius muscle. Conclusion: These findings indicate that compared with the level walking climbing stairs, ramps and muscle activities of lower extremity during each showed different results. It can be seen that in accordance with the terms of gait are different muscles group recruitment.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.2
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• pp.157-166
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• 1995

To investigate walkability of ramps, walking patterns of 18 healthy adults,12 aged 20 to 26 and 6 aged 68 to 76,were studied at free,rhythm constrained walking up or down ramp using goniometer and footswitch Ramp inclinations were set 4,8,12,16,20 degrees. The results were as follows. 1)The step length of subjects were decreased significantly in12$^{\circ}C$′or 16′free downramp walking. With regard to step length, some subject groups walked abnormally in 16" or 20" ramp walking 2) The step width of subjects were increased significantly in 12" or 16" ramp walking. 3) The cadence duration of some subject groups were increased in 12" upramp walking. 4) The double stance duration and double stance ratio of some subject groups were increased significantly in 8",12", or 16"upramp walking. 5) The maximum knee flexion angle of stance phase were increased in 12" ramp walking. 6)Most temporal parameters and spatial parameters of gait were increased or decreassd greatly between 4" ramp and 8" ramp or between 8′ramp and 12′ramp. But statistics significancy were not recognized 7) The results suggest that ramp inclination less than 8′(14%) -12′(21%) is desirable for the normal gait the ramp inclination must not exceed 16" -20" in unavoidable circumstances.

• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.79-87
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• 2007

The interchanges of urban freeways have many problems with traffic operation due to high off-ramp flows and frequent congestion at adjacent intersections. The flow exiting from off-ramps is affected by the operational status and traffic volume conditions of the nearest signalized intersection. As a result, off-ramp flow cannot exit and the queue backs up the freeway mainline when queues from the signalized intersection form up to the junction of the off-ramp and street. The spacing between an off-ramp and an adjacent intersection is likely to determine the traffic conditions at the adjacent intersection. However, the current design guidelines do not consider such a factor. This study is to develop a model calculating the spacing between off-ramps and adjacent intersections considering the signal, traffic, and road conditions. The variables affecting the model in this study are effective green time (g/C), volume-capacity ratio (v/c), the number of lanes, and off-ramp volume. Various scenarios are designed to represent the effects of the variables and the road networks are constructed using VISSIM, which is a common traffic micro-simulation software package. The queue length is derived from VISSIM and this length is considered as the recommended spacing between the off-ramp and the adjacent intersection. Through the simulation analysis, regression models are developed to calculate the queue length reflecting the various conditions such as signals, traffic, and road configurations. The developed model can be used to create road design guidelines to determine the location of off-ramps in the planning stage.