• Journal of the Korean association of regional geographers
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• v.14 no.1
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• pp.84-92
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• 2008

The first pine wilt damage in Korea, which called AIDS of pine, was found out at Mt. Geumjeong of Pusan province in 1988. The damage area spread 53's city, Gun, Gu throughout the Gyeongsangnamdo in December 2005 since then find out. The best treatment for these damaged forests is well known as fumigation method after early detection. But early detection by an observer is very difficult because of the damaged forest areas are spread over huge range. Also the access of observer is difficult in condition of Korea topographical characteristic. In this study, an attempt was done to investigation about early detection of pine wilt damage using near infrared CCD camera.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.279-282
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• 2011

Projectile can be damaged during the storage and handling. Maximum range calculation of the ammunition was performed on the assumption that each projectiles have 1.5mm/3.3mm axisymetric dent on the surface. Drag coefficient for trajectory calculation was delivered from CFD using commercial software FLUENT. In the result of CFD, damaged projectiles those have 1.5mm/3.3mm axisymetric dent have similar drag coefficient compare with normal projectile in the region of subsonic. But, in supersonic region, drag coefficient was increased 3%, 9% each in average. In the result of trajectory calculation, Maximum rage was decreased 1%, 3% each.

• Journal of the Korean Society of Hazard Mitigation
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• v.1 no.2 s.2
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• pp.63-74
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• 2001

In this paper the feasibility of Nondestructive Damage Detection (NDD) in large structures is demonstrated via simulating vibration monitoring of such structures. The theory of NDD for truss type structures is formulated. To examine the feasibility of the theory, a finite element model of a 3-D truss structure, which consists of sixteen bays and includes 246 elements, is developed to simulate damage. Four damage cases are simulated numerically and the cases range from the structure being damaged in one location to the structure being damaged in three locations. For the given modal parameters, this study reveals very good results for small amounts of damage as well as large damage.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.10 s.175
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• pp.80-89
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• 2005

In this paper, time-frequency analysis using wavelet packet transform and advanced-MDSA (Multiple Dimensional Spectral Analysis) which based on wavelet packet transform is applied fur fault source identification and diagnosis of early detection of fault non-stationary sound/vibration signals. This method is analyzing the signal in the plane of instantaneous time and instantaneous frequency. The results of ordinary coherence function, which obtained by wavelet packet analysis, showed the possibility of early fault detection by analysis at the instantaneous time. So, by checking the coherence function trend, it is possible to detect which signal contains the major fault signal and to know how much the system is damaged. Finally, It is impossible to monitor the system is damaged or undamaged by using conventional method, because crest factor is almost constant under the range of magnitude of fault signal as its approach to normal signal. However instantaneous coherence function showed that a little change of fault signal is possible to monitor the system condition. And it is possible to predict the maintenance time by condition based maintenance for any stationary or non-stationary signals.

• Journal of Biosystems Engineering
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• v.32 no.2 s.121
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• pp.77-83
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• 2007

The purpose of this study is to find optimal conditions for various outlet clearances of prototype garlic clove separator with a rotating cone in the constant inlet clearance and cone height. Optimal outlet clearance from medium to small size garlics was 25 mm at the $200{\sim}400rpm$. For large garlic, optimal outlet clearances of Namdo and Uiseong garlic were 34 mm and 37 mm, respectively, in the range of $300{\sim}400rpm$. The proportion of garlic separation was over 95% for all quality of garlics. The proportions of damaged garlics at 25 mm and 28 mm outlet clearances were below 5% and below 10%, respectively. Therefore, in order to maintain high performance of garlic separation for the various varieties and qualities, the rotating cone type separator should be designed with cone speed ranges of $200{\sim}400rpm$ and the outlet clearance ranges of $25{\sim}37 mm$. The outlet clearance of the separator should be easily controlled within those ranges.

• Journal of the Korean Society of Marine Environment & Safety
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• v.1 no.2
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• pp.107-118
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• 1995

This study is for decision making on distribution of resources so as to improve the effectiveness of initial disaster relief efforts. It is very important that relief efforts should be accomplished appropriately at the initial disaster. Furthermore, efficient allocation of relief resources such as rescuer, shelter, relief goods, relief funds, medical and relief equipments is also the first step to achieve main objective of relief efforts when disaster occurs. For this purpose, this study establishes flood as a imaginery disaster and develops a model for efficient distribution of resources when flood outbreaks. This model fixes initial 72 hours, which is subdivided into three intervals, as a initial disaster range. The model is to set a prioity against alloction of relief resources by each time zone which is related to damaged degree( Red Tag, Yellow Tag, Green Tag). Experts in this field input their experience into this model, and these are analyzed by Analytic Hierachy Process(AHP)/Expert Choice(EC) software. Therefore, we can decide a prioity against distribution of resources by each time zone which is in accordance with damaged degree. The result of this study would be helpful to a person who is in charge of relief from calamity in order him to make a decision toward distribution of resources.

• Journal of Conservation Science
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• v.35 no.1
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• pp.71-80
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• 2019

This study examined the applicability of digital technologies based on three-dimensional(3D) scanning, modeling, and printing to the restoration of damaged artifacts. First, 3D close-range scanning was utilized to make a high-resolution polygon mesh model of a roof-end tile with a missing part, and a 3D virtual restoration of the missing part was conducted using a haptic interface. Furthermore, the virtual restoration model was printed out with a 3D printer using the material extrusion method and a PLA filament. Then, the additive structure of the printed output with a scanning electron microscope was observed and its shape accuracy was analyzed through 3D deviation analysis. It was discovered that the 3D printing output of the missing part has high dimensional accuracy and layer thickness, thus fitting extremely well with the fracture surface of the original roof-end tile. The convergence of digital virtual restoration based on 3D scanning and 3D printing technology has helped in minimizing contact with the artifact and broadening the choice of restoration materials significantly. In the future, if the efficiency of the virtual restoration modeling process is improved and the material stability of the printed output for the purpose of restoration is sufficiently verified, the usability of 3D digital technologies in cultural heritage restoration will increase.

• Explosives and Blasting
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• v.28 no.2
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• pp.1-16
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• 2010

This study focuses on the phenomenon that the blast damaged zone developed on rock slope surfaces can be affected by joint characteristics rather than by explosive power when the pre-splitting is applied to excavate a jointed rock slope. The characteristics of rock joints on a slope were investigated and categorized them into 4 cases. Also an image processing system has been used for comparing the distribution pattern of rock blocks. From this investigation, it was found that the rock blocks bigger than 2,000 mm occupied 42% in the case of single joint set and it showed the well efficiency of pre-splitting blast. In cases of 2~3 parallel joint sets and 2~3 intersecting joint sets are developed on rock surfaces, the rock blocks in the range of 1,000~2,000 mm occupied 43.6% and 35.8%, respectively, and it showed that the efficiency of pre-splitting was decreased. When more than 3 joint sets are randomly developed, however, the rock blocks in the range of 250~500 mm occupied 35% and there was no block bigger than 1,000 mm. This denotes that the blasting with pre-splitting was not effective. The numerical analysis using PFC2D showed that the blast damaged zone in a rock mass could be directly influenced by the pre-splitting. It is, therefore, required to investigate the discontinuity pattern on rock surfaces in advance, when the pre-splitting method is applied to excavate jointed rock slopes and to apply a flexible blating design with a consideration of the joint characteristics.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.396-399
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• 2010

Purpose: In hand injury, pedicle is usually damaged by avulsion injury or crushing injury. Because of postoperative pedicle obliteration, it is often hard to save the injured hand and fingers, even after successful replantation. The author introduces three cases of extensive hand injury, and successful results after applicatoin of multiple venous grafts to these patients. Methods: In all cases there was no circulation in any finger. In the first case, some vessels were extracted, so venous graft was applied to two sites of severely damaged venous sites. In the second case, venous grafts were applied to all four digital arteries of all fingers except thumb which got severely crushed, and two sites of dorsal veins. In the third case, venous graft was applied to all four digital arteries of all five fingers, and two sites of dorsal veins and palmar veins each. Results: In all cases, survival of hands and fingers was successful. In the second case, however, amputation in thumb and little finger at DIP joint level was inevitable, because of its severe damage, and the large dorsal defect on index finger was filled with DIEP free flap. Thumb was reconstructed with toe-to-thumb free flap, and additional debulking procedures and contracture release is furtherly needed. In the first case, additional surgery was done, as FDP tendon got re-ruptured, but in long term follow-up, satisfactory range of motion was attained. In the third case, FTSG on dorsal skin region was planned. as flap on dorsal area got partial necrosis. Conclusion: In hand injury, there are many structures to be repaired, but sometimes venous graft is avoided for its long operating time. Even though the length of damaged vessel is enough for anastomosis, the endothelium is often damaged (zone of injury). In extensive hand injury, successful reconstruction would be possible with active venous graft to all vessels suspicious for damage.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.4
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• pp.211-221
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• 2021

The Rabbit grass(Trifolium Repens, call it 'Clover') is a representative harmful plant of lawn, and it starts growing earlier than lawn, forming a water pipe on top of the lawn and hindering the photosynthesis and growth of the lawn. As a result, in competition between lawn and clover, clover territory spreads, but lawn is damaged and dried up. Damage to the affected lawn area will accelerate during the rainy season as well as during the plant's rear stage, spreading the area where soil is exposed. Therefore, the restoration of damaged lawn is causing psychological stress and a lot of economic burden. The purpose of this study is to distinguish clover which is a representative harmful plant on lawn, to identify the distribution of damaged areas due to the spread of clover, and to review of changes in vegetation before and after the eradication of clover. For this purpose, a time series analysis of three vegetation indices calculated based on images of convergence Drone with RGB(Red Green Blue) and BG-NIR(Near Infra Red)sensors was reviewed to identify the separation between lawn and clover for selective eradication, and the distribution of damaged lawn for recovery plan. In particular, examined timeseries changes in the ecology of clover before and after the weed-whacking by manual and brush cutter. And also, the method of distinguishing lawn from clover was explored during the mid-year period of growth of the two plants. This study shows that the time series analysis of the MGRVI(Modified Green-Red Vegetation Index), NDVI(Normalized Difference Vegetation Index), and MSAVI(Modified Soil Adjusted Vegetation Index) indices of drone-based RGB and BG-NIR images according to the growth characteristics between lawn and clover can confirm the availability of change trends after lawn damage and clover eradication.