• International Journal of Highway Engineering
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• 제17권1호
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• pp.129-142
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• 2015

PURPOSES : The purpose of this study is to suggest a basis for setting appropriate safety goals specifically related to the threshold zone luminance in a vehicular traffic tunnel. METHODS : In the test, drivers were divided into two groups. One group consisted of all drivers (average drivers) group with an age ratio of drivers holding domestic driver's license and driver group by age to produce threshold zone luminance in the tunnel. The threshold zone luminance produced as a result was used to analyze how it affects the safety level of each driver group and provide a basis for setting an appropriate safety criterion that can be used to determine threshold zone luminance. We used test equipment, test conditions, and ananalysis of threshold zone luminance identical to that reported by ChoandJung(2014) but the values of adaptation luminance in our analys is were expanded to range from100 to $10,000cd/m^2$. RESULTS : Adaptation luminance and threshold zone luminance are found to be related by a quadratic function. The threshold zone luminance needed by older drivers to ensure a certain safety level is significantly higher than that for drivers of other age brackets when adaptation luminance increases. 56% of older drivers are at an increased risk of an accident at the same luminance for which the safety level of average drivers is 75%. The safety level that can be achieved for older drivers increases to above 60% when threshold zone luminance level is set with the goal of attaining a safety level of more than 85% for average drivers. The safety level that can be attained for average drivers is above 90% when the threshold zone luminance is high enough to ensure over 75% in the safety level of older drivers. Results of this study are applicable to highways and others whose designed speed is 100 km/h. CONCLUSIONS : Threshold zone luminance determined on the basis of drivers having average visual ability is of limited value as a performance standard for ensuring the safety of older drivers. Hence, safety level for older drivers should be considered separately from safety levels for drivers with an average ability to avoid risk. Upward adjustment of older drivers' safety level in the process of determining appropriate threshold zone luminance in a vehicular traffic tunnel may bring both tangible and intangible benefit as a result of reducing accidents. However, there is an associated dollar cost arising from installing and operating lights. As a result, the economic impact of these trade-offs should also be considered.

• Journal of the Korean Society of Environmental Restoration Technology
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• 제8권1호
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• pp.63-72
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• 2005

Chirisan National Park, the first and largest one out of 20 national parks in Korea, is divided into five zones. They are composed of nature preservation zone, natural environment zone, natural residential zone, concentrated residential zone, and collective facility zone. However, the park is not a continuous habitat: roads, trails, local residences, and various facilities created the habitat mosaics severely fragmented. We investigated the fragmentation pattern of the park due to roads and mountain trails using GIS. Based on perimeter length, area, and the ratio of perimeter to area of each patch, we obtained landscape analysis indices which reflect the regularity of the patch shape. The 1 m-wide hiking trails divided the park into 491 fragments. The legal trails with 1.5 m - 3 m width which have been heavily used by hikers generate 58 fragments. Even the nature preservation zone, corresponding to a core zone comprising 31.8% of the park area, was divided into 37 fragments because of the roads and mountain trails. With the different widths of buffer applied, the core sizes of the fragments were reduced. When the 60 m buffer was applied, the patch interior areas ranged from 0.0001 to 47.77 $km^2$ with a mean of 7.08 $km^2$. The landscape shape indices were far greater than 1 for most of the cases with a maximum value of 25. These results clearly indicate that Chirisan National Park is not a continuous habitat, but mosaics of small, irregularly shaped habitat fragments. It is necessary to take the size and shape of the fragmented habitats into consideration when nature conservation is planned, especially for large wildlife such as brown bears.

• Journal of the Korean Society of Safety
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• 제24권1호
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• pp.78-88
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• 2009

As the silver population rapidly increased, it became more urgent to establish a scheme of the traffic safety for the old. As part of the scheme, a polity to apply 'designation of the silver zone' was legislated into law. However, the standard quoting 'the silver zone should be within 300m - radius of the relevant facility' was considered homogeneous and even limited to apply its original objective. This study was to introduce a new standard to select the silver zone reflecting the actual scale. Consequently, I hope that this study would be useful reference for further development and the approach in the research could be legislated into law for more efficient designation and operation of the silver zone.

• Solar Energy
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• 제7권2호
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• pp.22-29
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• 1987

This paper dealed with thickness variation of bottom heat sotrage zone due to salinity and flow rate of extration hot brine in small test solar pond (0.5m wide, 0.5m high, 1.0m long). Testing apparatus and situation were follows: 7.1 cm of height of suction diffuser and 1.8cm of height of discharge diffuser above the test pond respectively, 0.3cm of slot size of suction diffuser, 1.0cm of slot size of discharge diffuser, 47cm of length of the slot; heating of hot water ($75^{\circ}C$) through separated hot water tank, discharge of the brine into storage zone through discharge diffuser, the extration of the brine through suction diffuser, circulation of the extracted brine through a heat exchanger (cooler). Following results were obtained through the experiments. 1. In small test solar pond, the typical three zone which showed up in real solar pond were established. 2. Richardson Number was used more effectively to confirm hydrodynamic stability of the stratified flow. 3. The thickness of non convective layer had a great effect on the heat storage of the bottom convective layer, then the temperature of bottom convective layer had a relation to that of upper convective layer. 4. Optimum operating condition in the test pond was on 10%-15% of salt concentration and $0.05m^3/hr$ of flow rate of extraction hot brine. 5. Following thickness of 3 zones were available to obtain under optimum operation condition: o bottom storage zone: $30%{\pm}10%$ of total pond depth o non-convective zone: $40%{\pm}10%$ of total pond depth o Upper surface zone: $20%{\pm}10%$ of total pond depth.

• Journal of The Geomorphological Association of Korea
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• 제24권3호
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• pp.13-25
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• 2017

This study is quantitative reconstruction of palaeo sea level records around Sinduk-ri, Gochang-Gun. 7 cores were collected from GC14 to GC18 in order to examine the entire sedimentary facies and reconstruct the sea level records. The cores were analysed by AMS, sedimentary facies, diatom and WA-pls. As a result of the diatom analysis, diatom zone were classified as No diatom zone, B1 zone, M zone and B2 zone. The result of WA-pls was that the sea level was about 1.5m lower than the present level around 6,000 BP and about 1m lower during last 5,000 BP. Thereafter, sea level rose to the present during the Mc sub-diatom zone period. Moreover, during the Md sub-diatom zone period, sea level was about 0.5m higher than the present.

• Journal of radiological science and technology
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• 제25권1호
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• pp.55-62
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• 2002

Aneurysm-mimicking findings were frequently visualized due to hemodynamical causes of dephasing effects around area of A-com artery during magnetic resonance angiography(MRA) and these kind of phenomena have not been clearly known yet. We investigated the hemodynamical patterns of dephasing effect around area of the A-com artery that might be a cause of false intracranial aneurysms on MRA. For experimental study, We used hand-made silicon phantoms of the asymmetric A-com artery as like a bifurcation configuration. In a closed circulatory system with UHDC computer driven cardiac pump system. MRA and fast digital subfraction angiography(DSA) involved the use of these phantoms. Flow patterns were evaluated with axial and coronal imaging of MRA(2D-TOF, 3D-TOF) and DSA of Phantoms constructed from an automated closed-type circulatory system filled with glycerol solution [circulation fluid(glycerol:water = 1:1.4)]. These findings were then compared with those obtained from computational fluid dynamic(CFD) for inter-experimental correlation study. Imaging findings of MRA, DSA and CFD on inflow zone according to the following: a) MRA demonstrated high signal intensity zone as inflow zone on silicon phantom; b) Patterns of DSA were well matched with MRA on trajectory of inflow zone; and c) CFD were well matched with MRA on the pattern of main flow. Imaging findings of MRA. DSA and CFD on turbulent flow zone according to the following: a) MRA demonstrated hyposignal intensity zone at shoulder and axillar zone of main inflow; b) DSA delineated prominent vortex flow at the same area. The hemodynamical causes of signal defect, which could Induce the false aneurysm on MRA, turned out to be dephasing effects at axilla area of bifurcation from turbulent flow as the results of MRA, DSA and CFD.

• Geophysics and Geophysical Exploration
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• 제7권1호
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• pp.62-69
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• 2004

The objective of this study is to estimate the distribution of a zone disturbed by excavation (EDZ) around tunnels that have been excavated at about 500 m depth in pre-Tertiary hard sedimentary rock. One of the most important tasks is to evaluate changes in the dynamic stability and permeability of the rock around the tunnels, by investigating the properties of the rock after the excavation. We performed resistivity and acoustic tomography using two boreholes, 5 m in length, drilled horizontally from the wall of a tunnel in pre-Tertiary hard conglomerate. By these methods, we detected a low-resistivity and low-velocity zone 1 m in thickness around the wall of the tunnel. The resulting profiles were verified by permeability and evaporation tests performed at the same boreholes. This anomalous zone matched a high-permeability zone caused by open fractures. Next, we performed resistivity monitoring along annular survey lines in a tunnel excavated in pre-Tertiary hard shale by a tunnel-boring machine (TBM). We detected anomalous zones in 2D resistivity profiles surrounding the tunnel. A low-resistivity zone 1 m in thickness was detected around the tunnel when one year had passed after the excavation. However, two years later, the resistivity around the tunnel had increased in a portion, about 30 cm in thickness, of this zone. To investigate this change, we studied the relationship between groundwater flow from the surroundings and evaporation from the wall around the tunnel. These features were verified by the relationship between the resistivity and porosity of rocks obtained by laboratory tests on core samples. Furthermore, the profiles matched well with highly permeable zones detected by permeability and evaporation tests at a horizontal borehole drilled near the survey line. We conclude that the anomalous zones in these profiles indicate the EDZ around the tunnel.

• Journal of the Korean Society of Industry Convergence
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• 제27권1호
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• pp.9-15
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• 2024

In this study, the mechanical properties of friction stir welded A6061-T6 were evaluated. This material is used as a battery pack case material for electric vehicles. The Vickers hardness, tensile strength, and yield stress of the friction stir welding (FSW) specimen were all smaller than those of the base metal specimen. As the heat input increased, the nugget zone widened, and there were differences in hardness according to the base metal zone, heat affected zone, thermal-mechanical affected zone, and nugget zone. Mechanical properties were not proportional to heat input, and the thermal-mechanical affected zone on the advancing side was the smallest in all conditions. This is because the material flow speed increased on the advancing side, where the welding direction and the tool rotation direction were the same, forming a distinct boundary with mechanical deformation.

• The Journal of Asian Finance, Economics and Business
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• 제9권7호
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• pp.41-52
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• 2022

This paper analyzes the advantages and opportunities of regional development prospects of the China (Anhui) Pilot Free Trade Zone. In addition, it provides suggestions for the future development of the Anhui Pilot Free Trade Zone. The establishment of the Anhui Pilot Free Trade Zone is a major platform for Anhui Province, China, to serve the nation's opening-up strategy to the world and an opportunity for the Anhui region to enhance the level of an open economy. The development plan points out that the Anhui Pilot Free Trade Zone 1) takes institutional innovation as the core, 2) complies with the requirements of the innovation-driven development and promotion of the Yangtze River Delta regional integration development strategy, and 3) plays a vital node role in promoting the construction of the Belt and Road Initiative, and 4) accelerates the construction of scientific and technological innovation sources, advanced manufacturing and strategic emerging industries. The findings of this study highlight three critical achievements as follows: 1) optimization and improvement of the business environment have progressed, 2) the conversion rate of scientific and technological innovation achievements has increased, and 3) advanced high-tech manufacturing and strategic emerging industries are clustered and developed.

• The Korean Journal of Malacology
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• 제5권1호
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• pp.10-28
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• 1989

A study on the distribution and community structure of benthic macroinvertebrates on the intertidal zone of Cheju Island was carried out from June 1988 to May 1989. The macroinvertebrates collected and identified were composed of 7 phyla, 14 classes, 29 orders, 71 families and 135 species in this study. The dominant species of the upper tidal zone were Nodilittorina granularis and Heminerita japonica, those of the middle tidal zone were Monodonta neritoides and Lunella coronata coreensis, However, Monodonta neritoides and Chlorostoma arhyrostoma lischkei were dominant in the lower tidal zone. Community dominant indices were significantly high in the upper tidal zone. Macuoinvertebrates species which have the ability of resistance to the physical factors such as, strong waves and exposure to the hot sunlight were mainly distributed on the intertidal zone of Cheju Island. The difference in the number of species among seasons was not significant, but thao among zones was quite apparent and the lower the zone, the more abundant.