• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.5
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• pp.121-133
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• 2017

Since the mid 1990s, policies have been actively promoted to improve safety and pedestrian environment around the school such as the improvement of School zone. However, the prevention of accidents was not effective because it did not extend to the school road where the main transportation route for children's commuting takes place. In addition, due to the rapid increase of automobiles, trunk road traffic in the peak time bypasses the back roads, which threatens children's safety and the environment by invading the school area, which is the main living space of children. In this study, the characteristics of domestic children's traffic accidents were investigated and the problems were analyzed by conducting a field survey on Yeouido Secondary School in Seoul and Unjung Elementary School in Gyeonggi Province. In addition, Variable speed limit signs and Beacons were installed in the pedestrian road of comunity including School zone, and the effects of facilities on the speed of vehicles were analyzed. As a result of the analysis, the Variable speed limit sign showed a deceleration effect of about 8.3km/h, and the Beacon showed a phenomenon in which the traveling speed of 0.8km/h increased only slightly. In addition, the traffic violation rate of passenger cars, buses, and lorries decreased by about 3% as a result of investigating the number of traffic violation vehicles before and after installation.

• Investigative Magnetic Resonance Imaging
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• v.20 no.2
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• pp.105-113
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• 2016

Purpose: Susceptibility vessel sign (SVS) on gradient echo image, which is caused by MR signal loss due to arterial thrombosis, has been reported in acute middle cerebral artery (MCA) infarction. However, the reported sensitivity and diagnostic accuracy of SVS have been variable. Susceptibility-weighted imaging (SWI) is a newly developed MR sequence. Recent studies have found that SWI may be useful in the field of cerebrovascular diseases, especially for detecting the presence of prominent veins, microbleeds and the SVS. The purpose of this study was to evaluate the diagnostic values of SWI for the detection of hyperacute MCA occlusion. Materials and Methods: Sixty-nine patients (37 males, 32 females; 46-89 years old [mean, 69.1]) with acute stroke involving the MCA territory underwent MR imaging within 6 hours after the symptom onset. MR examination included T2, FLAIR (fluid-attenuated inversion recovery), DWI, SWI, PWI (perfusion-weighted imaging), contrast-enhanced MR angiography (MRA) and contrast-enhanced T1. Of these patients, 28 patients also underwent digital subtraction angiography (DSA) within 2 hours after MR examination. Presence or absence of SVS on SWI was assessed without knowledge of clinical, DSA and other MR imaging findings. Results: On MRA or DSA, 34 patients (49.3%) showed MCA occlusion. Of these patients, SVS was detected in 30 (88.2%) on SWI. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of SWI were 88.2%, 97.1%, 96.8%, 89.5% and 92.8%, respectively. Conclusion: SWI was sensitive, specific and accurate for the detection of hyperacute MCA occlusion.

• Journal of Korean Society of Steel Construction
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• v.18 no.1
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• pp.11-22
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• 2006

Message Signs (VMS) structures offer an increase in traffic safety through their ability to relay massages to motorists for warnings of hazards ahead, traffic congestion, accidents, and lane closings. The geometry of these signs sometimes results in the significant cyclic loading of the supports structure due to wind gusts, which can result from passing trucks or from natural wind. This study presents the results of analytical and experimental investigations of VMS structures. The commercially available softwareGTSTRUDL (2003) was used to perform space-frame structural analyses of these welded tubular structures. Fatigue evaluations were performed using stress ranges from field measurements and from structural analyses. Based on the results of the structural analyses that were conducted, where fatigue design loadings that had been derived from AASHTO Specifications for Structural Supports for Highway Signs, Luminaries, and Traffic Signals (2001) were used, the structures that had been studied were found not to have infinite fatigue life. According to the limited measurements that were made in this study, the fatigue design loadings derived from AASHTO Specifications (2001) appear to be conservative, but they are not overly conservative. The results of this study should be used to make a reasonable design of VMS structures, and to maintain their standards.

• Journal of Astronomy and Space Sciences
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• v.28 no.2
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• pp.123-132
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• 2011

It is generally believed that the occurrence of a magnetic storm depends upon the solar wind conditions, particularly the southward interplanetary magnetic field (IMF) component. To understand the relationship between solar wind parameters and magnetic storms, variations in magnetic field polarity and solar wind parameters during magnetic storms are examined. A total of 156 storms during the period of 1997~2003 are used. According to the interplanetary driver, magnetic storms are divided into three types, which are coronal mass ejection (CME)-driven storms, co-rotating interaction region (CIR)-driven storms, and complicated type storms. Complicated types were not included in this study. For this purpose, the manner in which the direction change of IMF $B_y$ and $B_z$ components (in geocentric solar magnetospheric coordinate system coordinate) during the main phase is related with the development of the storm is examined. The time-integrated solar wind parameters are compared with the time-integrated disturbance storm time (Dst) index during the main phase of each magnetic storm. The time lag with the storm size is also investigated. Some results are worth noting: CME-driven storms, under steady conditions of $B_z$ < 0, represent more than half of the storms in number. That is, it is found that the average number of storms for negative sign of IMF $B_z$ (T1~T4) is high, at 56.4%, 53.0%, and 63.7% in each storm category, respectively. However, for the CIR-driven storms, the percentage of moderate storms is only 29.2%, while the number of intense storms is more than half (60.0%) under the $B_z$ < 0 condition. It is found that the correlation is highest between the time-integrated IMF $B_z$ and the time-integrated Dst index for the CME-driven storms. On the other hand, for the CIR-driven storms, a high correlation is found, with the correlation coefficient being 0.93, between time-integrated Dst index and time-integrated solar wind speed, while a low correlation, 0.51, is found between timeintegrated $B_z$ and time-integrated Dst index. The relationship between storm size and time lag in terms of hours from $B_z$ minimum to Dst minimum values is investigated. For the CME-driven storms, time lag of 26% of moderate storms is one hour, whereas time lag of 33% of moderate storms is two hours for the CIR-driven storms. The average values of solar wind parameters for the CME and CIR-driven storms are also examined. The average values of ${\mid}Dst_{min}{\mid}$ and ${\mid}B_{zmin}{\mid}$ for the CME-driven storms are higher than those of CIR-driven storms, while the average value of temperature is lower.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3418-3426
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• 2009

The purpose of this study was to investigate the feasibility of field operation protocol for cardiopulmonary resuscitation(CPR) in person with non-traumatic arrest. This study was performed from May 1 through June 27, 2008, and subjects were 150 students who are attending the department of Emergency Medical Service in J and K universities which located in Jeollabuk-do and Jeollanam-do areas. Practical conformance was verified using by nonequivalent control group pretest-posttest design. This study divided into two groups; experimental group that employed field operation protocol and control group that applied conventional CPR protocol, and comparative analyzed statistically the necessary time of the items of each protocol. The results indicated that each performance time of 18 items was reduced over 3 seconds except 5 items(assessment of consciousness, airway control, two times of artificial respiration, check of circulation, and five cycles of CPR). And time of 6 items(intubation, peripheral intravenous line, reassessment of consciousness, pupil reaction, carotid artery pulse, and vital sign) was minimized more than 60 seconds, and total performing time was shortened 110.85 seconds. The results suggested that total performing time in pre and post test where the protocol was applied for two groups showed a statistically significant decrease(t=-6.580, p=.000). Consequently, field operation protocol for cardiopulmonary resuscitation(CPR) in person with non-traumatic arrest will be a available manual which support prompt and accurate decision making, and improve emergency medical service.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.440-451
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• 2000

This study was conducted in order to provide essential data and relevant management proposal to conserve and maintain big and old trees in a rational way. For the field survey, 77 big and old trees preserved by the laws in Chollabuk-do, Korea were investigated. The study results are summarized as follows : 1. To conserve and manage big and old trees, the valuable trees have been designated as natural monument trees and protection-needed trees. There are 141 individuals of 37 species designated as natural monuments and 10,049 individuals of 102 species designated as protection-needed trees. 2. Management budget for natural monument trees was devoted at 70% from the national expenditure, but that for protection-needed trees was devoted at 98% from the local expenditure. 3. Standardized sign boards and sign stones for natural monument trees were well placed and other protection facilities such as fences, branch supports and branch holdings were established. On the other hand, management of protection-needed trees was deficient overall. 4. Problems for designation process and management of protection-needed trees could include items such as insufficient management budget, various development activities, land ownership, misjudgement of tree age and species identification, unsatisfaction of sign board placement, insufficient surgery for damaged trees, pavement around tree root system and environmental pollution around the trees. 5. In order to improve the existing management methods of big and old trees, the following schemes were suggested : the development of practical criteria for natural monument and protection-needed trees, nationwide surveys of big and old tree resources, the security of national budget, securing sufficient spaces for the tree growth, specialization of management systems, extended practices of tree form management, establishment of permanent standard signs and consideration of opinions of village residents.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.38.2-38.2
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• 2010

Biomimetc is a new domain of learning that proposes a solution getting clues from nature. There seems to be a sign of this phenomenon in fields of Renewable Energy. Foe example, Wind power was imitate the whale's fin that was improve efficiency of generating energy. This study focused on the photovoltaic generation as the instance of applying biomimetic. Efficiency is the most important factor in field of Photovoltaic generation. When given solar cell taking the sun light, most important fields of the study are absorb more light and increase the quantity of generation. For improving efficiency, the solar cell were builded up textures of taking a pyramid form, such a surface structure taking a role for remaining the light. This effects do the role as increasing absorbing efficiency. Such phenomenon calls Light Trapping, locking up the light on the surface of solar cell for a long time. Light is a vital factor to plants in the nature. Plants grow up through the photosynthesis that absorbing light for growth and propagation. So, plants make a effort how can absorb more the light in poor surroundings. This study set up a goal that imitates the minute surface structure of plants and applies to the existing solar cells's surface structure, so it can improve the efficiency of absorbing light. We used Light Tools software analyzing geometrical optics to analyze efficiency about new designed textures on the computer. We made a comparison between existing textures and new designed textures. Consequently, new designed textures were advanced efficiency, absorbing rates of light increasing about 7 percent. In comparison with existing and new textures, advancing about 20 percent in the efficient aspect.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.4
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• pp.13-21
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• 2011

Update of road facilities database such as road sign, traffic lights, and street lights is interesting business in a local government. Recently, existing road facilities database, aerial photo and topographic map are referred for the installation and complement of road facilities. But it is difficult to comprehend road facilities' condition and additional expenses may appear in field survey. Therefore, it is necessary to establish and update road facility DB and many studies has been carried out to efficiently collect road related spatial data. In this study, the establishment of various complicated road facility DB was conducted by images that had been obtained by digital camera with a built-in bluetooth and DGPS. Results showed that road facility DB was constructed effectively and suggested the possibility of road facility management using images based on coordinate through accuracy analyses using total-station surveying. And using digital camera and DGPS is expected to effective real-time update and management of road facility DB.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.1 s.9
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• pp.55-63
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• 2006

Speeding is one of the major causes of traffic accidnets in urban areas. Driver feedback sign(DFS) is a traffic control device that can be used for many traffic environments including work zones, school zones, and roadways. In this paper, the effectiveness of DFS was evaluated through a field study using speed data collected from before and after study periods. In addition traffic safety improvement was also quantitatively estimated using the variance of speed data collected. Staistical test results showed that the speed difference was statistically significant, and the distribution of speed data was also shifted greatly. Therefore, it was concluded that installing the DFS in roadways might lead to unifomity of speed of traffic flow, thus, potential safety improvement might be expected.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.2
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• pp.1-11
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• 2010

The provision of warning information on upcoming hazards leading to potential crash occurrence is a significant countermeasure to prevent crashes on the highway. This study presents a methodology for selecting more effective warning messages using a multi-criteria value function. The understandability, preference level, and message reading time were used as measures of effectiveness (MOE) for messages. Expert judgements were incorporated into the value function by analytical hierarchical process (AHP) technique. Field experiments to evaluate the warning messages were conducted in a testbed section on the Jungboo-Naeryuk freeway. The proposed methodology would be a useful tool to support the design of various traffic information messages.