• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.6
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• pp.337-342
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• 2018

Wave flume that enables generating water waves is a core research facility for physical experiment related to coastal engineering works. Recently, a new wave flume of 50 m length was constructed in Korea. The wave flume has a sloped section on its bottom. A novel wave generating system incorporating most-updated wave maker theory was introduced to the flume. In addition, water circulating system for adjusting water level was installed beneath the flume. These technical features and detailed specifications of the wave flume are described in this paper.

• Journal of the Society of Disaster Information
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• v.15 no.2
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• pp.259-267
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• 2019

Purpose: In this paper adhesive-bonded cylindrical lap joints are analyzed by assuming that the adherends are elastic and the adhesive is linearly viscoelastic. Method: The distribution of the stresses in the adhensive is evaluated using the Finite Element Method. Nuverical examples for identical and different adherends bonded through a four parameter viscoelastic solid adhesive are illustrated. Results: The stress distribution in the adhesive layer with respect to time is shown. The stress distribution in the adhesive layer with respect to time is shown. The results are also shown that adherend thickness and elastic modulus give effect on the normalized stress. Conclusion: In this study, the stress distribution of the adhesive layer of the wrapped cylindrical body considering the viscoelasticity of the adhesive layer was numerically analyzed by using a four - element elastomer model.

• Journal of the Korean Orthopaedic Association
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• v.55 no.4
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• pp.338-342
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• 2020

Periosteal chondroma is a rare, slow-growing, benign cartilaginous tumor that develops between the periosteum and cortex, but there are no reports of multiple periosteal chondroma of the toes. A 19-year-old male presented with a palpable mass of the right fourth toe with tenderness for one year. A radiology examination revealed multiple, radio-lucent lesions with mild cortical irregularity. The magnetic resonance imaging findings were chondrogenic tumors with multiple, well-defined T1-low and T2-high signal enhanced lesions involved in the fourth proximal, middle, and distal phalanges. The tumors were removed by a surgical resection and curettage. Histologically, the tumors were proven to be periosteal chondroma.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.445-449
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• 2021

Insertional bone cysts of the knee joint mainly appear in the form of small cysts at the bone attachment of the cruciate ligaments, and are usually not associated with symptoms. The authors report a 31-year-old man diagnosed with a huge insertional bone cyst connected to the femoral attachment of the posterior cruciate ligament in the knee joint, who obtained good results after curettage and bone cement filling.

• Journal of the Korean Orthopaedic Association
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• v.54 no.5
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• pp.447-451
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• 2019

This case report describes the unusual occurrence of a flexor digitorum profundus avulsion secondary to an enchondroma of the distal phalanx of the middle finger. The enchondroma was treated by simple curettage with an autogenous bone graft harvested from the olecranon. The avulsed bone fragment was reattached to the distal phalanx using the pull-out suture technique. Bony union and full function of the digit were achieved.

• Journal of the Korean association of regional geographers
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• v.16 no.3
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• pp.216-223
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• 2010

The study deals with classification of drought-flood intensity using Z index based on the precipitation data in Hyesan of the past 50 years(1957~2006). The frequencies of years and four seasons of flood drought and their change features have also been analyzed based on tendency analysis and MESA and wavelet methods. Results show that the annual and seasonal frequencies of flood-drought exceed 24% in Hyesan and flood-drought disasters have been high frequency. Inter-decadal variability seems to be clear in autumn but those of inter-annual variability are obvious in other three seasons and years. Recently the probability of drought disaster become higher in autumn. The flood disaster in other three seasons and years are estimated to become higher in the future.

• The Journal of the Korean bone and joint tumor society
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• v.6 no.1
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• pp.30-34
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• 2000

Giant cell tumor of the small bones of the hands and feet is rare. Giant cell tumors in these locations develop at young age, are more commonly multifocal, and show the higher risk of recurrence than those at the end of the long bone. It should be differentiated from the other lesions of the hands, such as giant cell reparative granuloma, aneurysmal bone cyst and enchondroma. We experienced a case of giant cell tumor in the proximal phalanx of the left hand with swelling and pain. Curettage and bone graft were performed. Histologically large number of giant cells were distributed diffusely in the highly cellular stroma containing sheets of mononuclear cells. Secondary aneurysmal bone cyst and hemorrhage were associated.

• The Journal of the Korean bone and joint tumor society
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• v.20 no.1
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• pp.32-35
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• 2014

Rosai-Dorfman disease (RDD) is an idiopathic histioproliferative disorder of lymph node and extranodal site. Bone involvement is very rare. We report a case of extranodal RDD of the tibia in 32-year old male. The patient presented with pain with no evidence of lymphadenopathy. Clinico-radiologic diagnosis was metastatic carcinoma or Langerhans cell histiocytosis, but, histopathologic examination confirmed the diagnosis with RDD. We performed curettage on the osteolytic lesion of tibia. In South Korea, there was no report about RDD of the extremity and we want to report this case with review of the literature.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.4
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• pp.263-272
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• 2001

Recently, some attempts to construct slit caisson-type breakwaters are made in Korea. Since slit caisson-type breakwaters are suitable for relatively deep sea areas, a lot of theoretical and experimental researches have been performed. In this study, the reflection characteristics of vertical slit caisson breakwaters are investigated based on the measured data in two-dimensional hydraulic model tests with irregular waves. The experiments were conducted for various cases; variation of porosity of perforated-wall, width of wave chamber, number of slits for single-and double-chamber, respectively. It is found that in the case when the wave steepness (H/L$_{s}$ ) is small, the reflection coefficients are large. The existing researches have shown that the wave reflection is minimized when the nondimensional width of wave chamber B/L is about 0.2~0.25 for the regular waves. However, for the irregular waves the reflection is lowest when $B/L_2$, is 0.13~0.15. For a same porosity condition, the wave dissipation is stronger as the width of s1it is larger. The double-chamber caisson is superior to single- chamber caisson in the wave dissipating effects.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.4
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• pp.232-241
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• 2003

The interaction of incident monochromiatic waves with N bottom-mounted porous circular cylinders is investigated in the frame of three-dimensional linear potential theory. The fluid domain is divided into N+l regions i.e. a single exterior region and N interior regions, and the diffraction potential in each fluid region is expressed by an eigenfunction expansion method (Williams and Li,2000). The analytic results show that the porous structure reduces both the wave forces and the run-up wave around the cylinder. To verify the developed model, the systematic model test with a line array of porous cylinders is conducted at the wave tank (30m$\times$7m$\times$1.5m). The analytic results are in good agreement with the experimental results within measured frequency range. It is concluded that the breakwater constructed with an array of porous circular cylinders shows the performance of an effective wave barrier together with the seawater-exchange effect and is considered to have vast potentials for the use of seawater-exchanging breakwater in the future.