• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1C
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• pp.45-51
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• 2010

In urban area, design and construction of civil engineering structures such as subway tunnel, underground space and deep excavation is impeded by unreliable site investigation. Variety of embedded objects, electric noises and traffic vibrations degrades the quality of site investigation, whatever the site-investigation technique would be. In this research, a preliminary research was performed to develop a dedicated site investigation technique for urban geotechnical sites, which can overcome the limitations of urban sites. HiRAS (Hybrid Integration of Surface Waves and Resistivity) technique which is the first outcome of the preliminary research was proposed in this paper. The technique combines surface wave as well as electrical resistivity. CapSASW method for surface-wave technique and PDC-R technique for electrical resistivity survey were incorporated to develop HiRAS technique. CapSASW method is a good method for evaluating material stiffness and PDC-R technique is a reliable method for determination of underground stratification even in a site with electrical noise. For the inversion analysis of HiRAS techniuqe, a site-specific relationship between stress-wave velocity and resistivity was employed. As for outgrowth of this research, the 2-D distribution of Poisson's ratio could be also determined.

• Composites Research
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• v.37 no.1
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• pp.46-52
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• 2024

The development of transportation methods has improved human transportation convenience and made it possible to expand the travel radius of people with disabilities who have difficulty moving. However, in the case of WAV (wheelchair Accessible Vehicle), the safety that may occur in a vehicle accident is still lower than that of regular passenger seats. In particular, in the case of a rear-end collision that may occur in a defenseless situation, it can cause fatal neck injuries to disabled passengers. Therefore, a more detailed design plan must be reflected in the headrest to be applied to WAV. In this study, a multi-cell headrest was proposed to implement local compression characteristic distribution of the headrest during rear-end collision of WAV. Afterwards, a correlation analysis was performed between the passenger's NIC (Neck Injury Criterion) and impact energy absorption using the data set construction through analysis and the clustering results using k-means clustering. As a result of clustering, it was confirmed that data clusters with similar characteristics were formed, and a correlation analysis between NIC and impact energy absorption through the characteristics of each cluster was performed. As a result of the analysis, it was confirmed that the softer the cell compression characteristics in Mid3 and Mid6, the more impact energy absorption increases, and the harder the cell compression characteristics in Front2, Mid3, and Mid6, the more effective it is in reducing NIC.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.367-375
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• 2023

This study developed a new distance metric for vessel trajectories, applicable to marine traffic control services in the Korean coastal waters. The proposed metric is designed through the weighted summation of the traditional Hausdorff distance, which measures the similarity between spatiotemporal data and incorporates the differences in the average Speed Over Ground (SOG) and the variance in Course Over Ground (COG) between two trajectories. To validate the effectiveness of this new metric, a comparative analysis was conducted using the actual Automatic Identification System (AIS) trajectory data, in conjunction with an agglomerative clustering algorithm. Data visualizations were used to confirm that the results of trajectory clustering, with the new metric, reflect geographical distances and the distribution of vessel behavioral characteristics more accurately, than conventional metrics such as the Hausdorff distance and Dynamic Time Warping distance. Quantitatively, based on the Davies-Bouldin index, the clustering results were found to be superior or comparable and demonstrated exceptional efficiency in computational distance calculation.

• Journal of the Korean earth science society
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• v.45 no.3
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• pp.214-223
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• 2024

The recent increase in maritime traffic and coastal leisure activities has led to a rise in various marine accidents. These incidents not only result in damage to human life and property but also pose a significant risk of marine pollution involving oil and hazardous and noxious substances (HNS) spills. Therefore, effective ship monitoring is crucial for preparing and for responding to marine accidents. This study conducted an aerial experiment utilizing hyperspectral remote sensing to develop a maritime ship monitoring system. Hyperspectral aerial measurements were carried out around Gungpyeong Port in the western coastal region of the Korean Peninsula, and spectral libraries were constructed for various ship decks. The spectral correlation similarity (SCS) technique was employed for ship detection, analyzing the spatial similarity distribution between hyperspectral images and ship spectra. As a result, 15 ships were detected in the hyperspectral images. The color of each ship's deck was classified based on the highest spectral similarity. The detected ships were verified by matching them with high-resolution digital mapping camera (DMC) images. This foundational study on the application of aerial hyperspectral sensors for maritime ship detection demonstrates their potential role in future remote sensing-based ship monitoring systems.

• Journal of Chest Surgery
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• v.40 no.7 s.276
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• pp.480-484
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• 2007

Background: Major vascular injuries can jeopardize a patient's life or imperil limb survival. We performed this study to establish an optimal management plan for vascular injuries. Material and Method: We retrospectively reviewed 26 cases of vascular injury that were treated at Pusan National University Hospital from May, 1999 to September, 2004. The age and sex distribution, the locations and causes of vascular injury, the diagnostic tools, the degree of injuries, clinical manifestations, the treatment modality and complications were reviewed. Result: The mean age was 39.5 years (range: $12{\sim}86$) and the male to female ratio was 22 : 4. The injuries were in 6 descending thoracic aortas, 4 femoral arteries, 4 popliteal veins and so on. The causes of injury were iatrogenic in 8 cases, traffic accident in 7, stab injury in 6 and industrial accident in 5. The most commonly used diagnostic tools were CT and angiography. The degrees of arterial injury were pseudoaneurysm in 10 cases, partial severance in 5, complete severance in 3 and thrombosis in 3. The degrees of venous injury were partial severance in 6 cases, complete severance in 2 and arteriovenous fistula in 2. The clinical manifestations were absence of pulse in 8 cases, coldness in 7, chest pain in 6, swelling in 5, bleeding in 5 and so on. The most frequently used type of revascularization was graft interposition in 11 cases. Two arteriovenous fistulae were repaired by endovascular procedure. There was one case of mortality due to multi-organ failure after hemorrhagic shock, There were three major amputations, and two of them were due to delayed diagnosis and treatment. Conclusion: A system for the early diagnosis and treatment is essential for improving limb salvage and patient mortality. As a consequence of the widespread application of endovascular procedures, the incidence of iatrogenic injuries has recently increased. Educating physicians is important for the prevention of iatrogenic injury. Easy communication and cooperation for earlier involvement of a vascular surgeon is also an important factor.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.1
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• pp.25-32
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• 2011

The number of patients requesting services of pediatric dental clinics has been steadily increasing in South Korea. The pediatric dental clinics are comprised of hospital-based clinics and local clinics. The purpose of this study was to analyze new-patient distribution and to survey the motives for visiting the department of pediatric dentistry at Seoul National University Dental Hospital(SNUDH), utilizing questionnaires for parents from May to July 2010. The results are as follows: 1. Age distribution showed that 0-3 year-olds formed the largest group of 29.3%. The average age of patients was 6.2 years old. 2. In the surveys for the parents, the major reason for visiting SNUDH was the referral from other clinics(30.6%). 3. The 75% of patients previously visited other clinics before visiting SNUDH. 1) The greater number of patients(52%) visited general practitioner's clinic than pediatric specialists(48%). 2) More than 90% of the patients visited SNUDH after visiting other clinics for reassuring diagnosis and referrals. 3) The crucial deterring factor of being treated at SNUDH was difficult accessibility.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.1
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• pp.89-96
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• 2002

Purpose : The purpose is to analyze the relationship between bone bruise in MRI and associated injuries after the knee joint trauma. Materials and Methods : Total 50 cases were reviewed, divided into two groups according to initial trauma energy. High-energy group (group I), such as traffic accident was 13 cases, low-energy group (group II), such as sports trauma was 37 cases. The type of the lesion was used the classification by Costa-Paz. The site of lesion was analyzed according to femoral/tibial, medial/lateral and anterior/middle/posterior site respectively. Associated injuries were confirmed by physical examination, radiograph, MRI and arthroscopy. Results : In group I there was a various distribution of the bone bruise in the knee joint according to mechanism of injury. The bone bruise with ACL injury was 38$\%$ only and the most frequent type was Costa-Paz type I (52.6 $\%$). In group II more frequent locations were the middle portion of the lateral femoral condyle and the posterior portion of the lateral tibial condyle. Bone bruise associated with ACL injury, was upto 56.8 $\%$ and the frequent type were Costa-Paz type II (48 $\%$), in order type I (42 $\%$). As a result, in the high-energy injury the bone bruise had a various location in both condyle and less frequently associated injury, but in the low-energy injury there was particularly frequent location of bone bruise, associated injury and type. Conclusions : We could assess the associated injury by analysis of the location and type of bone bruise, especially in the low-energy injury, e.g. sports injury. But further study will be necessary with more case analysis.

• Journal of the Korean Geographical Society
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• v.28 no.4
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• pp.321-355
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• 1993

This paper focuses on the geographical pattern of financial activities in the Korean urban system during 1975-1990, based on the assumption that financial activities can reveal control points in Korea's urban economy. In terms of spatial evolution of financial insitutions, different locational characteristics are revealed among different types of financial institutions, implying the role of urban hierarchy. Financial resources are highly concentrated in the capital region, Seoul and Kyonggi Province. Both centralization trends into the large metropolitan cities and relative declines of medium and small cities within the Korean urban system, have been experienced over the study period. Financial activities sustain relatively stable hierarchical structure in the urban hierarchy. Regarding the financial flows, dominant flow zones centered on major metropolitan cities are identified, clearly showing a prominant role of Seoul in financial flows in the entire urban system.

• Korean Journal of Remote Sensing
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• v.32 no.2
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• pp.105-118
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• 2016

The purpose of this study is to improve the classification system of sub-divided land cover map among the land cover maps provided by the Ministry of Environment. To accomplish the purpose, first, the overseas country land cover map classification items were examined in priority. Second, the area ratio of each item established by applying the previous sub-divided classification system was analyzed. Third, the survey on the improvement of classification system targeting the users (experts and general public) who actually used the sub-divided land cover map was carried out. Fourth, a new classification system which improved the previous system by reclassifying 41 classification items into 33 items was finally established. Fifth, the established land cover classification items were applied on study area, and the land cover classification result according to the improvement method was compared with the previous classification system. Ilsan area in Goyang city where there are diverse geographic features with various land surface characteristics such as the urbanization area and agricultural land were distributed evenly were selected as the study area. The basic images used in this study were 0.25 m aerial ortho-photographs captured by the National Geographic Information Institute (NGII), and digital topographic map, detailed stock map plan, land registration map and administrative area map were used as the relevant reference data. As a result of applying the improved classification system into the study area, the area of culture-sports, leisure facilities was $1.84km^2$ which was approximately more than twice larger in comparison to the previous classification system. Other areas such as transportation and communication system and educational administration facilities were not classified. The result of this study has meaningful significance that it reflects the efficiency for the establishment and renewal of sub-divided land cover map in the future and actual users' needs.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.1
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• pp.118-128
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• 2016

The purpose of this study is to present efficient methods of preserving and managing the fish shelter forest in Mulgun-ri on the southern coast of Korea on the basis of its humanistic, sociological and ecological characteristics. The study object is Korean natural monument No. 150, which is presumed to have been forested by descendants of Jeonju Lee Family who settled there, and village rituals are held every October to pray for the peace of the village. The forest is managed by Namhae-gun as a historical and cultural resource as well as its disaster-preventing, economic, and environmental and ecological functions. The linear form of the area is $23,962.6m^2$ and farmland(48.5%) and urbanization area(38.2%) are extensively located in its periphery area. Actual vegetation was sub-classified into three types of land according to use pressure and whether or not damage was done: land where its stratification was formed; land where it was restored, and the land where it was damaged. Plant communities were sub-classified into Aphananthe aspera community(I) and Zelkova serrata community(II) which had a low use pressure; Z. serrata-Chionanthus retusa-A. aspera community(III) and A. aspera-Z. serrata community(IV) which had a high use pressure; and Celtis sinensis-A. aspera community(V) whose underlayer was damaged by use. Fragmentation of the forest is under way and its inside vegetation growth is hampered due to the installation of traffic and resting facilities such as the through roads costal roads, wooden-deck walkways, parking lots, washstands, etc. As a restoration management plan for this, the following were required: an establishment of preferred restoration area; a selection of restoration vegetation species; and an appropriate restoration method. The damaged area($7,868.2m^2$) will have to be set up as the preferred restoration area; seedlings of restored vegetation species should be raised with dominant species within the forest(i.e., Z. serrata, A. aspera, C. sinensis, and C. retusa) as their 'mother trees' for the benefit of for the next-generation forest; and sub-tree and shrub layer should be complementarily planted with 5 and 115 trees(unit $100m^2$) respectively to facilitate the formation of a multi-layered vegetation structure. In addition, resting facilities scattered inside the forest should be demolished; and indiscriminate use of them should be controlled; management and monitoring should be carried out so that the area can be preserved and restored as a deciduous broad-leaved forest.