• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3C
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• pp.374-386
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• 2004

The mammogram provides the way to observe detailed internal organization of breasts to radiologists for the early detection. This paper is mainly focused on efficiently detecting the Microcalcification's Region Of Interest(ROI)s. Breast cancers can be caused from either microcalcifications or masses. Microcalcifications are appeared in a digital mammogram as tiny dots that have a little higher gray levels than their surrounding pixels. We can roughly determine the area which possibly contain microcalifications. In general, it is very challenging to find all the microcalcifications in a digital mammogram, because they are similar to some tissue parts of a breast. To efficiently detect microcalcifications ROI, we used four sequential processes; preprocessing for breast area detection, modified multilevel thresholding, ROI selection using simple thresholding filters and final ROI selection with two stages of neural networks. The filtering process with boundary conditions removes easily-distinguishable tissues while keeping all microcalcifications so that it cleans the thresholded mammogram images and speeds up the later processing by the average of 86％. The first neural network shows the average of 96.66％ recognition rate. The second neural network performs better by showing the average recognition rate 98.26％. By removing all tissues while keeping microcalcifications as much as possible, the next parts of a CAD system for detecting breast cancers can become much simpler.

• Geophysics and Geophysical Exploration
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• v.16 no.1
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• pp.36-44
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• 2013

We conducted the airborne magnetic and radiometric survey for the characterization of the black shale related and pyrometamorphic uranium deposits distributed in Geumsan area. For the successful characterization of the uranium deposits, the general geological and structural geological features were investigated based on the lithological and linear feature analysis to individual magnetic and radiometric data as the first step. Lithological analysis from the magnetic reduction to the pole and downward continuation map revealed that prominent positive anomalies caused by black and dark gray slate member were clearly recognized as magnetic sources. These results indicate that magnetic survey, even though it is not a direct method for the detection of uranium, can be a useful tool in uranium detection. By the linear feature analysis based on 2nd vertical derivative and curvature map, two linearments corresponded the gray hornfels and black slate member were extracted and in succession, the additional uranium potential zone was inferred. Final discrimination whether uranium-rich or not was confirmed by radiometric and uranium anomaly map. From these analysis, we finally concluded that uranium deposit originated by pyrometamorphic process was confined near the intrusive area only. On the contrary, it was found that black shale related uranium deposit is distributed and extended through out the entire survey area with south-west to north-east direction. In addition, from the linear feature analysis based on radiometric total anomaly map, the typical discontinuous characteristics were recognized in areas where uranium-contained linearments cross the faults. From the above discussion, we concluded that airborne magnetic and radiometric survey are complementary to each other. So it is preferable to carry out simultaneously for the efficient data processing and fruitful interpretation.

• Journal of the Korean association of regional geographers
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• v.18 no.3
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• pp.336-350
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• 2012

Cette $\acute{e}$tude a pour objectif d'analyser et d'expliquer le g$\acute{e}$osite de l'$\hat{I}$le de Geum-o pour connaitre les caract$\acute{e}$ristiques de cette r$\acute{e}$gion du point de vue $\acute{e}$cologique, historique et culturel $\grave{a}$ partir de ses ressources g$\acute{e}$omorphiques et g$\acute{e}$ologiques. Il y a plusieurs ressources g$\acute{e}$otouristiques sur $\hat{I}$le de Geum - o: la falaise de 'Miyeokneolbang' et 'Shinseondae'; la plage de Gigpo; la falaise et la caverne marine de 'Gualbaramtong'; le tombolo et l'$\hat{I}$le reli$\acute{e}$e $\grave{a}$ la terre de Choungsan; la coul$\acute{e}$e de roches de Jangji; la plage de cailloux de Jangji; le lieu des tuf et des andesite de la c$\hat{o}$te orientale. On a g$\acute{e}$n$\acute{e}$ralement d$\acute{e}$velopp$\acute{e}$ la couche s$\acute{e}$dimentaire et les roches volcaniques li$\acute{e}$es $\grave{a}$ la derni$\grave{e}$re p$\acute{e}$riode du m$\acute{e}$sozo$\ddot{i}$que. Une route g$\acute{e}$otouristique part de l'embarcad$\grave{e}$re de Hamgoumi sur l'$\hat{I}$le de Geum-o et continue du Nord-Ouest jusqu'au Sud-Est l'autre route part de la c$\hat{o}$te Est et continue en suivant la c$\hat{o}$te orientale. Nous proposons des panneaux d'explication g$\acute{e}$otouristique de Janji centr$\acute{e}$s sur la coul$\acute{e}$e de roches.

• Journal of the Korean Geotechnical Society
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• v.38 no.10
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• pp.31-40
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• 2022

This study compares elastic moduli calculated using two stiffness testing methods with different strain ranges to evaluate the stress-settlement characteristics of foundation support layers. Elastic moduli were calculated by the soil stiffness gauge (SSG) in the micro-strain range and the plate load test (PLT) in the medium strain range. To apply the elastic moduli obtained by the two testing methods with different strain ranges to the design and construction of foundation soils, the correlation between each measurement value should be identified in advance. As a result of the comparative analysis of the elastic moduli calculated using the two methods in weathered soil and rock, which are representative support layers in Korea, the calculated elastic moduli differed depending on the types of soil and stress conditions. For various soil types, the static elastic modulus obtained by the PLT was reduced by 56% because of the difference in the strain level of the test compared with the dynamic elastic modulus obtained by the SSG. Therefore, the results show that it is necessary to apply corrections to the stress distribution, stress level, and dynamic effect according to the ground stiffness to effectively use the SSG instead of the PLT.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.1
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• pp.34-44
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• 1998

Analysis of gravity, magnetic, and seismic reflection data from the Ulleung Basin, East Sea has provided some insights into the opening mechanism and crustal type of the basin. Free-air gravity anomaly data show positive anomalies of about 40~60 mgal near the Korea Plateau and Oki Bank and of about -20~20 mgal in the central basin. Bouguer gravity anomaly data exhibit NE-SW trending positive anomalies of about 150 mgal in the central basin which is interpreted to be related to high-density crustal material. Abrupt changes in both Free-air and Bouguer gravity anomaly profiles across the basin margins may be due to transition between continental and oceanic crusts. Magnetic anomalies in the basin are generally less than -400 nT. No stripe pattern is evident in the magnetic anomaly map but a NW-SE trending symmetric pattern is seen in some magnetic profiles. The symmetric pattern is probably associated with the high-density crustal material in the central basin suggested by Bouguer gravity anomaly. The acoustic basement in the deep part of the basin has only a small amount of local relief. No graben or half-graben structures are seen in the acoustic basement from which mechanical extension might be inferred. The lack of high-relief structures in the acoustic basement may suggest that the basin is underlain by oceanic crust or that the basement is overlain by thick volcanic layer which obscures the structures and relief of the basement. High-density crust in the central basin inferred from gravity data, abrupt changes in gravity anomalies across the basin margins, symmetric pattern seen in some magnetic anomaly profiles, and lack of relief in the acoustic basement may suggest sea-floor spreading origin of the Ulleung Basin.

• Radiation Oncology Journal
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• v.23 no.3
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• pp.143-156
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• 2005

Background: The best dose-fractionation regimen of the definitive radiotherapy for cervix cancer remains to be clearly determined. It seems to be partially attributed to the complexity of the affecting factors and the lack of detailed information on external and intra-cavitary fractionation. To find optimal practice guidelines, our experiences of the combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) were reviewed with detailed information of the various treatment parameters obtained from a large cohort of women treated homogeneously at a single institute. Materials and Methods: The subjects were 743 cervical cancer patients (Stage IB 198, IIA 77, IIB 364, IIIA 7, IIIB 89 and IVA 8) treated by radiotherapy alone, between 1990 and 1996. A total external beam radiotherapy (EBRT) dose of $23.4\~59.4$ Gy (Median 45.0) was delivered to the whole pelvis. High-dose-rate intracavitary brachytherapy (HDR-IBT) was also peformed using various fractionation schemes. A Midline block (MLB) was initiated after the delivery of $14.4\~43.2$ Gy (Median 36.0) of EBRT in 495 patients, while In the other 248 patients EBRT could not be used due to slow tumor regression or the huge initial bulk of tumor. The point A, actual bladder & rectal doses were individually assessed in all patients. The biologically effective dose (BED) to the tumor ($\alpha/\beta$=10) and late-responding tissues ($\alpha/\beta$=3) for both EBRT and HDR-ICBT were calculated. The total BED values to point A, the actual bladder and rectal reference points were the summation of the EBRT and HDR-ICBT. In addition to all the details on dose-fractionation, the other factors (i.e. the overall treatment time, physicians preference) that can affect the schedule of the definitive radiotherapy were also thoroughly analyzed. The association between MD-BED $Gy_3$ and the risk of complication was assessed using serial multiple logistic regression models. The associations between R-BED $Gy_3$ and rectal complications and between V-BED $Gy_3$ and bladder complications were assessed using multiple logistic regression models after adjustment for age, stage, tumor size and treatment duration. Serial Coxs proportional hazard regression models were used to estimate the relative risks of recurrence due to MD-BED $Gy_{10}$, and the treatment duration. Results: The overall complication rate for RTOG Grades $1\~4$ toxicities was $33.1\%$. The 5-year actuarial pelvic control rate for ail 743 patients was $83\%$. The midline cumulative BED dose, which is the sum of external midline BED and HDR-ICBT point A BED, ranged from 62.0 to 121.9 $Gy_{10}$ (median 93.0) for tumors and from 93.6 to 187.3 $Gy_3$ (median 137.6) for late responding tissues. The median cumulative values of actual rectal (R-BED $Gy_3$) and bladder Point BED (V-BED $Gy_3$) were 118.7 $Gy_3$ (range $48.8\~265.2$) and 126.1 $Gy_3$ (range: $54.9\~267.5$), respectively. MD-BED $Gy_3$ showed a good correlation with rectal (p=0.003), but not with bladder complications (p=0.095). R-BED $Gy_3$ had a very strong association (p=<0.0001), and was more predictive of rectal complications than A-BED $Gy_3$. B-BED $Gy_3$ also showed significance in the prediction of bladder complications in a trend test (p=0.0298). No statistically significant dose-response relationship for pelvic control was observed. The Sandwich and Continuous techniques, which differ according to when the ICR was inserted during the EBRT and due to the physicians preference, showed no differences in the local control and complication rates; there were also no differences in the 3 vs. 5 Gy fraction size of HDR-ICBT. Conclusion: The main reasons optimal dose-fractionation guidelines are not easily established is due to the absence of a dose-response relationship for tumor control as a result of the high-dose gradient of HDR-ICBT, individual differences In tumor responses to radiation therapy and the complexity of affecting factors. Therefore, in our opinion, there is a necessity for individualized tailored therapy, along with general guidelines, in the definitive radiation treatment for cervix cancer. This study also demonstrated the strong predictive value of actual rectal and bladder reference dosing therefore, vaginal gauze packing might be very Important. To maintain the BED dose to less than the threshold resulting in complication, early midline shielding, the HDR-ICBT total dose and fractional dose reduction should be considered.

• Journal of the Mineralogical Society of Korea
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• v.31 no.1
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• pp.1-12
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• 2018

A gravity core (RS14-C2) was collected at site RS14-C2 in the continental slope to the east of Pennell-Isellin Bank of the Ross Sea (Antarctica) during PNRA XXIX (Rosslope II Project) Expedition. In order to trace the sediment source, magnetic susceptibility (MS), sand fraction, and clay mineral compositions were analyzed, and AMS $^{14}C$ ages were dated. Core sediments consist mostly of hemipelagic sandy clay or silty clay including ice-rafted debris (IRD). AMS $^{14}C$ age of core-top indicates the modern and Holocene sediments. Based on AMS $^{14}C$ dating, sediment color, MS and sand fraction, core sediments are divided into interglacial and glacial intervals. The interglacial brown sediments are characterized by low MS and sand fraction, whereas the glacial gray sediments are characterized by high MS and sand fraction. Among clay mineral compositions of core sediments, illite is highest (61.8~76.7%), and chlorite (15.7~21.3%), kaolinite (3.6~15.4%), and smectite (0.9~5.1%) are in decreasing order, and these compositions are also divided into the interglacial and glacial/deglacial intervals. During the glacial period, the high content of illite and chlorite indicate sediment supply from the bedrocks of Transantarctic Mountains under the Ross Ice Sheet. In contrast, because of decreasing supply of illite and chlorite by the glacial retreat, smectite and kaolinite contents increased relatively during the interglacial period. During the interglacial period, smectite may be transported additionally by the northeastward flowing surface current from the coast of Victoria Land in the western Ross Sea. Kaolinite may be also supplied to the continental slope by the Antarctic Slope Current from the kaolin-rich metasedimentary rock outcropped on the Edward VII Peninsula.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1972.03a
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• pp.7-8
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• 1972

The effects of noise exposure are of two types: Nonauditory effects and auditory effects. Nonauditory effects of noise exposure are interference with communication by speech, sleeping and emotional behavior. The noise will cause the high blood pressure and rapid pulse, also that decrease the salivation and gastric juice. in experimentaly showed that the Corticoid hormon: Gonatotropic hormone were decrease and Thyrotropic hormoone is increase. Auditory effect of noise exposure. when the normal ear is exposed to noise at noise at hamful intensities (above 90㏈) for sufficiently long periods of time, a temoral depression of hearing results, disappearing after minutes or hours of rest. When the exposure longer or intesity greater is reached the Permanent threshold shift called noise-induced hearing loss. Hearing loss resulting from noise exposure presents legal as well as medical problems. The otologist who examines and evaluates the industrial hearing loss cases must be properly informed, not only concerning the otologic but also about the physical and legal aspects of the problems. The measurement of hearing ability is the most important part of a hearing conservation, both preplacement and periodic follow-up tests of hearing. The ideal hearing conservation program would be able to reduce or eliminate the hazardous noise at its source or by acoustic isolation of noisy working area and two ear protections (plugs and muff type) were developed for personal protection.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.485-505
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• 2022

On November 15, 2017, a Mw 5.4 Pohang Earthquake occurred at about 4 km hypocenter in the Heunghae area, and caused great damage to Pohang city, Korea. In the Heunghae area, which is the central part of the Pohang Basin, the Cretaceous Gyeongsang Supergroup and the Late Cretaceous to Early Paleogene Bulguksa igneous rocks as basement rocks and the Neogene Yeonil Group as the fillings of the Pohang Basin, are distributed. In this paper, structural and geological researches on the crustal deformations (folds, faults, joints) in the Pohang Basin and the coseismic ground deformations (sand volcanoes, ground cracks, pup-up structures) of Pohang Earthquake were carried out, and the deformation history of the Pohang Basin and characteristics of the coseismic ground deformations were considered. The crustal deformations were formed through at least five deformation stages before the Quaternary faulting: forming stages of the normal-slip (Gokgang fault) faults which strike (N)NE and dip at high angles, and the high-angle joints of E-W trend regionally recognized in Yeonil Group and the faults (sub)parallel to them, and the conjugate normal-slip faults (Heunghae fault and Hyeongsan fault) which strike E-W and dip at middle or low angles and the accompanying E-W folds, and the conjugate strike-slip faults dipped at high angles in which the (N)NW and E-W (NE) striking fault sets show the (reverse) sinistral and dextral strike-slips, respectively, and the conjugate reverse-slip faults in which the NNE and NNW striking fault sets dip at middle angles and the accompanying N-S folds. Sand volcanoes often exhibit linear arrangements (sub)parallel to ground cracks in the coseismic ground deformations. The N-S or (N)NE trending pop-up structures and ground cracks and E-W or (W)NW trending ground were formed by the reverse-slip movement of the earthquake source fault and the accompanying buckling folding of its hanging wall due to the maximum horizontal stress of the Pohang Earthquake source. These structural activities occurred extensively in the Heunghae area, which is at the hanging wall of the earthquake source fault, and caused enormous property damages here.

• Journal of Radiation Protection and Research
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• v.40 no.3
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• pp.162-167
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• 2015

Although the perfomance indicators of the nuclear power plants in Korea show optimal, it requires detailed analysis and discussion centered on the radiation dose. As analysis methods, analysis on the radiation dose of nuclear power plants over the past five years was assessed by comparing the relevant radiation dose of radiation workers and per capita average annual radiation dose of the world's major nuclear power stations was also analyzed. The radiation workers over the annual radiation dose limit of 50 mSv were not. The contrast ratio of the radiation exposure according to the reactor type was the normal operation of PHWR was 6.2% higher than those of the PWR. This shows the radiation work of PHWR during normal driving operation is much more than those of PWR. According to the Performance Indicators of the World Association of Nuclear Operator, the annual radiation dose per unit in 2013 showed 527 man-mSv of Korea is the best country among the major nuclear power generating states, the world average was 725 man-mSv. The annual per capita radiation dose is about 80% less than 1 mSv of the public dose limit and also the average per capita dose showed a very low level as 0.82 mSv. Workers in related organizations showed 1.07 mSv, the non-destructive inspection agency workers showed 3.87 mSv. The remarkable results were due to radiation reduced program such as development of radiation shielding and radiation protection. In conclusion, the radiation exposured dose of nuclear power plants workers in Korea showed a trend which is ideally reduced. But more are expected to be difficul and the psychological insecurity against the operation of the nuclear power plants is existed to the residents near the nuclear power plants. So the radiation dose reduction policy and radiation dose follow up study of nuclear power plants will be continously excuted.