• Title/Summary/Keyword: inversions

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Strategy for Improving the Resolution of Electrical-resistivity Inversions for Detecting Soft Ground at Shallow Depths (~ 10 m) (천부(약 10 m) 연약 지반 탐지를 위한 전기비저항 역산 해상도 향상 전략)

  • Jang, Hangilro;Song, Seo Young;Kim, Bitnarae;Nam, Myung Jin
    • The Journal of Engineering Geology
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    • v.28 no.3
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    • pp.367-377
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    • 2018
  • This study introduces a DC resistivity inversion method that incorporates structural and inequality constraints to enhance the resolution of resistivity inversions, and presents sample inversion results with these constraints. In the constrained inversions, a base model is constructed from a layered model through interpretation of other geophysical data. Inversion tests establish that both the structural and inequality constraints produce better resistivity models than the unconstrained inversion. However, the inequality inversion not only reproduces the exact layered structure of the background, it reproduces conductive anomalies at a depth of ~ 10 m when an inexact base model of electrical resistivity is used.

Inversion Phenomena of Temperature in the Southern Sea of Korea (한국 남해의 수온역전현상)

  • KIM Hee-Joon;YUG Sang-Sup
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.16 no.2
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    • pp.111-116
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    • 1983
  • Temperature inversions are investigated by using the oceanographic data (1965-1979) obtained in the Southern Sea of Korea. The temperature inversions in winter occur about six times more frequently than those in sumner. In the west region of the Southern Sea, the inversions are found at any depth in winter. In the east region of the Southern Sea, however, they usually appear in surface layer in winter. Such inversion phenomena in winter can be explained by surface cooling effects associated with a net heat loss at the sea surface and a southward advection of surface cold water due to north-westerly monsoon. In summer the inversion layers are usually formed below the thermocline in the west region of the Southern Sea, and in surface layer in the east region. The former results from the mixing between the Tsushima Warm Current and the Yellow Sea Bottom Cold Water, and the latter is generated by an offshore flow of cold water near coast due to southwesterly wind.

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DETERMINATION OF PERMUTATION GRAPHS

  • KOH, YOUNGMEE;REE, SANGWOOK
    • Honam Mathematical Journal
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    • v.27 no.2
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    • pp.183-194
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    • 2005
  • A permutation graph is the graph of inversions in a permutation. Here we determine whether a given labelled graph is a permutation graph or not and when a graph is a permutation graph we find the associated permutation. We also characterize all the 2-regular permutation graphs.

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A Cytogenetic Study in Patients Referred for Suspected Chromosomal Abnormalities (염색체 이상 환자의 세포 유전학적 연구)

  • Oh, S.K.;Lee, H.H.;Moon, S.Y.;Chang, Y.S.
    • Clinical and Experimental Reproductive Medicine
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    • v.12 no.2
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    • pp.39-57
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    • 1985
  • Presented in this paper the data from a chromosome study of 397 patients referred for suspected chromosmal abnormalities. Karyotypes were obtained using short-term blood culture and direct method. Of these 238 patients had normal chromosome complements; 159 (40.1%) patients had chromosome abnormality. Among all patients with chromosome abnormalities, 82.4% (131/159) had aberrations of chromosome number, the others 17.60/0 (28/159\ had aberrations of chromosome structure. Ten had a chromosome rearrangement; Five of them were reciprocal and five Robertsonian translocations. Four patients with pericentric inversions and one with paracentric inversions and four with isochromosomes were observed. There were four patients with marker chromosome, two patients had a chromosome insertion; and three others. (additional abnormal chromosomes.) Thus the results of the present study indicate the importance of cytogenetic evaluation in clinically abnormal patients.

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Inversion Phenomena of Temperature in the Yellow Sea (한국 서해의 수온역전 현상)

  • Kim, Hui-Jun;Yun, Hong-Ju;Yang, Seong-Gi
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.18 no.2
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    • pp.91-96
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    • 1982
  • Temperature inversions are investigated by using the oceanographic data obtained in the Yellow Sea from 1965 to 1979. The temperature inversions are found in every depth in almost all areas of the Yellow Sea. While in summer, they frequently occur below thermocline in the west region of the Jeju Island. Such phenomena in winter can be explained by surface cooling effects associated with a net heat loss at the surface and a southward advection of cold water, and those in summer result from the process of mixing between the Yellow Sea Warm Current and the Yellow Sea Bottom Cold Water.

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A Study on Nocturnal Inversion at Urban Area in Winter (동절기 도심지 야간 기온역전에 관한 연구)

  • Zheng, Hai-Yan;Lee, Kyoo-Seock
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.13 no.1
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    • pp.40-46
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    • 2010
  • In urban area, inversion layer prevents air pollutants from being dispersed. To determine nocturnal inversion characteristics at SookMyung Girls' High School near high-rise residential commercial complex buildings in Seoul, air temperature and humidity data were observed at 10minute interval from December 1st, 2007 to May 2nd, 2008. Temperature-Humidity (T-H) sensors were installed at SMG (SookMyung_Ground) and SMR (SookMyung_Roof), and then these two data were compared, analyzed and examined to illustrate air temperature differences of SMG and SMR. After the analysis, the maximum nocturnal inversion was observed by $3.3^{\circ}C$ at 18:10 on December 26th 2007, at that time the weather condition was clear and weak wind. Nocturnal inversions began 2-3 hours before sunset and it reached maximum inversion just after sunset and continued through nighttime until sunrise or 1-2 hours after sunrise. In terms of seasonal variation nocturnal inversions occurred dominantly in March and April rather than winter season.

Cytogenetic Studies of 384 Couples with Recurrent Abortion (반복유산을 경험한 384부부의 세포유전학적 연구)

  • Choi, Soo-Kyung;Min, Eung-Ki;Roh, Sung-Il;Paik, Yong-Kyun;Lyu, Myung-Soo
    • Clinical and Experimental Reproductive Medicine
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    • v.18 no.2
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    • pp.223-231
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    • 1991
  • During the years 1984 to 1989, in order to determine of chromosome abnormalities are associated with recurrent spontaneous abortions, cytogenetic studies were performed 384 couples. Abnormal karyotypes were found in 51(13.3%) couples. There was no apparent relation with the number of abortions. The abnormalities were as follows: 17(4.4%) balanced translocation; 15(3.9%) mosaicisms; 17(4.4%) pericentric inversion; 2(0.5%) addition or isochromosome. Chromosome abnormalities were observed in 34(67%) of the wives and 17(33%) of the husbands. In addition, we detected polymorphic variants of chromosomes in 89(23.2%) subjects. Reciprocal translocations(13/17) were more common than the robertsonian type(4/17). All of the mosaicisms were associated with the sex chromosomes in 10 females and 5 males subjects. Pericentric inversions were most common in chromosome 9. Compared to previously studied general populations, significantly higher frequencies of translocations, mosaicisms and inversions were found in couples with repetitive spontaneous abortion. This suggests that couples should have chromosome studies after two or more abortions.

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A Study on Interpretation of Gravity Data on Two-Dimensional Geologic Structures by Iterative Nonlinear Inverse (반복적 비선형역산에 의한 2차원 지질구조의 중력자료 해석 연구)

  • Ko, Chin-Surk;Yang, Seung-Jin
    • Economic and Environmental Geology
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    • v.27 no.5
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    • pp.479-489
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    • 1994
  • In this paper, the iterative least-squares inversion method is used to determine shapes and density contrasts of 2-D structures from the gravity data. The 2-D structures are represented by their cross-sections of N-sided polygons with density contrasts which are constant or varying with depth. Gravity data are calculated by theoretical formulas for the above structure models. The data are considered as observed ones and used for inversions. The inversions are performed by the following processes: I) polygon's vertices and density contrast are initially assumed, 2) gravity are calculated for the assumed model and error between the true (observed) and calculated gravity are determined, 3) new vertices and density contrast are determined from the error by using the damped least-squares inversion method, and 4) final model is determined when the error is very small. Results of this study show that the shape and density contrast of each model are accurately determined when the density contrast is constant or vertical density gradient is known. In case where the density gradient is unknown, the inversion gives incorrect results. But the shape and density gradient of the model are determined when the surface density contrast is known.

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