• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.86-95
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• 2006

Brillouin backscatter is a type of reflection that occurs when light is shone into an optical fibre. Brillouin reflections are very sensitive to changes in the fibre arising from external effects, such as temperature, strain and pressure. We report here several case studies on the measurement of strain using Brillouin reflections. A mechanical bending test of an I beam, deployed with both fiber optic sensors and conventional strain gauge rosettes, was performed with the aim of evaluating: (1) the capability and technical limit of the DTSS technology for strain profile sensing; (2) the reliability of strain measurement using fiber optic sensor. The average values of strains obtained from both DTSS and strain gauges (corresponding to the deflection of I beam) showed a linear relationship and an excellent one-to-one match. A practical application of DTSS technology as an early warning system for land sliding or subsidence was examined through a field test at a hillside. Extremely strong, lightweight, rugged, survivable tight-buffered cables, designed for optimal strain transfer to the fibre, were used and clamped on the subsurface at a depth of about 50cm. It was proved that DTSS measurements could detect the exact position and the progress of strain changes induced by land sliding and subsidence. We also carried out the first ever distributed dynamic strain measurement (10Hz) on the Korean Train eXpress(KTX) railway track in Daejeon, Korea. The aim was to analyse the integrity of a section of track that had recently been repaired. The Sensornet DTSS was used to monitor this 85m section of track while a KTX train passed over. In the repaired section the strain increases to levels of 90 microstrain, whereas in the section of regular track the strain is in the region of 30-50 microstrain. The results were excellent since they demonstrate that the DTSS is able to measure small, dynamic changes in strain in rails during normal operating conditions. The current 10km range of the DTSS creates a potential to monitor the integrity of large lengths of track, and especially higher risk sections such as bridges, repaired track and areas at risk of subsidence.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1565-1570
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• 2016

Background: Central neurocytomas are rare neuronal neoplasms with a favorable prognosis. They are typically located in the lateral ventricles of the brain and mostly histologically correspond to WHO grade II with a Mib 1 labelling index of <2%. Similar tumors located in the cerebral hemispheres and spinal cord, for example, are called "extraventricular neurocytomas". A few tumors histologically show atypia, mitoses, vascular proliferation and/or necrosis and a Mib 1 index >2 % and are designated as "atypical neurocytomas. Aim: The aim of our study was to describe the common as well as unusual morphologic features and the role of various immunohistochemical stains in the diagnosis of these rare tumors. Materials and Methods: We retrieved and reviewed 35 cases diagnosed between 2001 and 2015. Results: Sixty percent of patients were males, and the mean age was 26 years. 31 cases (88.6%) were intraventricular and 4(11.4%) were extraventricular. Histologically, 6 cases (17.1%) were compatible with "atypical neurocytomas". All cases showed the classic morphology comprising nests and sheets of uniform, round cells with uniform round to oval nuclei with finely speckled chromatin and perinuclear cytoplasmic clearing (halos). All cases also showed delicate, fibrillary, neuropil-like matrices. Other common histologic features included capillary-sized blood vessels in a branching pattern in 57.1%, foci of calcification in 34.3% and perivascular pseudorosettes in 20%. Rare findings included Homer-Wright or true rosettes in 8.6% and ganglioid cells in 2.9%. Synaptophysin was the most consistent and valuable marker, being positive in almost all cases. GFAP positivity in tumor cells was seen in 25.7% of cases. Follow up was available in 13 patients. Of these 9 had histologically typical and 4 had atypical tumors. Only 1 (with an atypical neurocytoma) died, probably due to complications of surgery within one month, while 12 (including 3 with atypical neurocytomas) remained alive. Recurrence developed in 1 of these 12 patients (histologically consistent with typical morphology) almost 9 years after surgery. Only 4 patients, including 2 with atypical tumors, received postoperative radiotherapy, all with surgery in 2010 or later. Overall, prognosis was excellent with prolonged, recurrence free survival and most patients, even without receiving radiation therapy, were alive and well for many years, even a decade or more after surgery, without developing any recurrence, indicating the benign nature of these neoplasms.

• Journal of the Korean Society of Costume
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• v.62 no.4
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• pp.107-122
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• 2012

The purpose of this study is to investigate the changes and developments that occurred as a result of the exchanges of gyeong-geum(經錦), a warp-faced compound weave of East Asia, and wie-geum(緯錦), a weft-faced compound weave of West Asia. In order to maximize the efficiency of this research, topics were narrowed down to the weaving skills and patterns, and the period was limited to the Tang dynasty. The systematic characteristics and differences of gyeong-geum and wie-geum were compared and contrasted through different works of literature. Then the excavated remains of geum-textiles were analyzed and the characteristics of the geum-textiles were defined in chronological order. The origin of wie-geum is traced back to the time when West Asia started to imitate the weaving style of the East Asian gyeong-geum. When combined with the weaving skills of the West Asian, gyeong-geum, which broke through the West and developed into the weft-faced compound twill silk, or samite. The exchange of geum-textiles took place as the techniques of gastric filament woven geum-textiles returned to the East. Along with the pearl roundel motifs of Sassanian Persia, mythical animals and western motifs of hunter patterns were used for the patterns of wie-geumin during the early Tang dynasty. This tendency is related to pa-sa-geum(波斯錦), ho-geum(胡錦), beon-geum(番錦) according to the recorded literature. The 8th and 9th century are periods when the West Asian Persian style was abandoned and the East Asian style, samite, was established. Not only did S twist silk threads replace Z twists, but also the repetition of patterns unfolded along with the weft and the warp. As this tendency was strengthened after the 9th century, the expression of patterns became more vividly colorful and showed both elements of naturalism and realism. The characteristics of the Bosangwha(寶相花) pattern in the Tang period were established with the rampantly repeated rosettes with birds often holding auspicious branches, that fly amid floral compositions.