• Title/Summary/Keyword: well log

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Temperature Dependence of Initial Adsorption Rate of Soybean (콩의 초기 흡습속도의 온도의존성)

  • Kim, Jong-Goon;Kim, Sung-Kon
    • Korean Journal of Food Science and Technology
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    • v.21 no.3
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    • pp.360-363
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    • 1989
  • The initial moisture adsorption of soybeans was examined under the conditions : RH, 57-86% ; temperature, $16^{\circ}-34^{\circ}C$, and storage time, 100 hours. The changes in moisture content as a function of time held a relation: log dw/dt=b log t + log a, where w is the moisture content (%, db), t is time (hour) and a and b are the parameters which were calculated from the experimental data. The calculated moisture content from the equation agreed well with the measured moisture content. The activation energy of initial adsorption rate was about 15500cal/g-mole in all soybeans. The initial adsorption rate at temperature $16^{\circ}-28^{\circ}C$ could be estimated from a following equation : log(log dw/dt)=-15500/2.303RT.

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Formation Identification using Anisotropic Parameters from Sonic and Density Logs (음파검층과 밀도검층 자료에서 산출된 이방성 변수를 이용한 지층 구분)

  • Jang, Seonghyung;Kim, Tae Youn;Hwang, Seho
    • The Journal of Engineering Geology
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    • v.27 no.3
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    • pp.323-330
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    • 2017
  • For the formation identification, surface geological survey, drill core analysis, core description and well log analysis are widely used. Among them well log analysis is a popular method with drill core analysis, since it measures continuously physical properties at in-situ. In this study we calculated Thomsen anisotropic parameters (${\varepsilon},\;{\delta},\;{\eta}$) after applying Backus averaging method to the P wave velocity, S wave velocity, and density logs. The well log data application of Blackfoot, Canada, shows the formation could be divided by 12 layers. This shows that Thomsen anisotropic parameters for identifying formation using anisotropic parameters is useful if there is no natural gamma log that is widely used for the formation identification.

A Study on the Method of Building 3D GIS Database Using the Statistical Estimating Methods of Well Log for Balancing Seismic Data (탄성파 자료 보정용 검층 기록의 통계적 추정방법을 이용한 3차원 GIS DB 구축방법에 관한 연구)

  • Um, Jong-Seok
    • Journal of Korea Spatial Information System Society
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    • v.5 no.1 s.9
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    • pp.39-47
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    • 2003
  • The purpose of this paper is to present the method of acquiring 3D GIS data using the statistical estimating methods of Well Log for balancing Seismic data. We use the reflection coefficients of seismic data to get the parameters for the reservoir characterization and we balance the reflection coefficients of seismic data using well log to increase the confidence of the estimated result. Well logs are required to balance the reflection coefficients at the point where seismic data are acquired. In this research, we discuss the geostatistical estimation methods and we applied these methods to real data. Kriging gives high weights to the close well logs, which means estimated results are mainly affected by close well log. High value of cross variograms gave big difference on cokriging result comparing to kriging results and low value of cross variogram gave little differences.

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Modeling of Breast Cancer Prognostic Factors Using a Parametric Log-Logistic Model in Fars Province, Southern Iran

  • Zare, Najaf;Doostfatemeh, Marzieh;Rezaianzadeh, Abass
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.4
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    • pp.1533-1537
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    • 2012
  • In general, breast cancer is the most common malignancy among women in developed as well as some developing countries, often being the second leading cause of cancer mortality after lung cancer. Using a parametric log-logistic model to consider the effects of prognostic factors, the present study focused on the 5-year survival of women with the diagnosis of breast cancer in Southern Iran. A total of 1,148 women who were diagnosed with primary invasive breast cancer from January 2001 to January 2005 were included and divided into three prognosis groups: poor, medium, and good. The survival times as well as the hazard rates of the three different groups were compared. The log-logistic model was employed as the best parametric model which could explain survival times. The hazard rates of the poor and the medium prognosis groups were respectively 13 and 3 times greater than in the good prognosis group. Also, the difference between the overall survival rates of the poor and the medium prognosis groups was highly significant in comparison to the good prognosis group. Use of the parametric log-logistic model - also a proportional odds model - allowed assessment of the natural process of the disease based on hazard and identification of trends.

A Technique to Enhance Performance of Log-based Flash Memory File Systems (로그기반 플래시 메모리 파일 시스템 성능 향상 기법)

  • Ryu, Junkil;Park, Chanik
    • IEMEK Journal of Embedded Systems and Applications
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    • v.2 no.3
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    • pp.184-193
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    • 2007
  • Flash memory adoption in the mobile devices is increasing or vanous multimedia services such as audio, videos, and games. Although the traditional research issues such as out-place update, garbage collection, and wear-leveling are important, the performance, memory usage, and fast mount issues of flash memory file system are becoming much more important than ever because flash memory capacity is rapidly increasing. In this paper, we address the problems of the existing log-based flash memory file systems analytically and propose an efficient log-based file system, which produces higher performance, less memory usage and mount time than the existing log-based file systems. Our ideas are applied to a well-known log-based flash memory file system (YAFFS2) and the performance tests are conducted by comparing our prototype with YAFFS2. The experimental results show that our prototype achieves higher performance, less system memory usage, and faster mounting than YAFFS2, which is better than JFFS2.

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Variable Selection with Log-Density in Logistic Regression Model (로지스틱회귀모형에서 로그-밀도비를 이용한 변수의 선택)

  • Kahng, Myung-Wook;Shin, Eun-Young
    • Communications for Statistical Applications and Methods
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    • v.19 no.1
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    • pp.1-11
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    • 2012
  • We present methods to study the log-density ratio of the conditional densities of the predictors given the response variable in the logistic regression model. This allows us to select which predictors are needed and how they should be included in the model. If the conditional distributions are skewed, the distributions can be considered as gamma distributions. A simulation study shows that the linear and log terms are required in general. If the conditional distributions of xjy for the two groups overlap significantly, we need both the linear and log terms; however, only the linear or log term is needed in the model if they are well separated.

Line Detection Using Log Hough Transform (Log-Hough 변환을 이용한 직선검출)

  • 정헌상;황의봉
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.13 no.3
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    • pp.118-123
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    • 1999
  • Hough transform is well employed to retect or recognize the lines in image processing or in computer vision. Curve of the logarithm of ranges against the bearing does not change its shape according to data trints. This fact suggests that calculation cost can be remarkably reduced. An effective line detection algorithm is represented.sented.

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An O($n^2log n$) Algorithm for the Linear Knapsack Problem with SUB and Extended GUB Constraints (단순상한 및 확장된 일반상한제약을 갖는 선형배낭문제의 O($n^2log n$) 해법)

    • Journal of the Korean Operations Research and Management Science Society
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    • v.22 no.3
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    • pp.1-9
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    • 1997
  • We present an extension of the well-known generalized upper bound (GUB) constraint and consider a linear knapsack problem with both the extended GUB constraints and the simple upper bound (SUB) constraints. An efficient algorithm of order O($n^2log n$) is developed by exploiting structural properties and applying binary search to ordered solution sets, where n is the total number of variables. A numerical example is presented.

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A Simulation Approach for Testing Non-hierarchical Log-linear Models

  • Park, Hyun-Jip;Hong, Chong-Sun
    • Communications for Statistical Applications and Methods
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    • v.6 no.2
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    • pp.357-366
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    • 1999
  • Let us assume that two different log-linear models are selected by various model selection methods. When these are non-hierarchical it is not easy to choose one of these models. In this paper the well-known Cox's statistic is applied to compare these non-hierarchical log-linear models. Since it is impossible to obtain the analytic solution about the problem we proposed a alternative method by extending Pesaran and pesaran's (1993) simulation approach. We find that the values of proposed test statistic and the estimates are very much stable with some empirical results.

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Geophysical Well-log Analysis of Andesite and Sedimentary Rocks in Myodo-dong, Yeosu, Southern Korea (여수시 묘도 부근 퇴적암과 안산암에서 물리검층에 대한 자료해석)

  • Leem, Kook-Mook;Park, Jong-Oh;Yu, Young-Chul;Song, Moo-Young
    • Journal of the Korean earth science society
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    • v.30 no.4
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    • pp.401-408
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    • 2009
  • We carried out the Suspension PS log and gamma-gamma log in andesite and sedimentary rocks distributed near the area of Myodo-dong, Yeosu. The main purpose of this study was to find out the distribution of seismic velocities and densities and to analyze the correlation of the two rocks by comparing their geophysical well logs with rock cores. The distributions of P and S-wave velocities for two rocks represented in the study area showed a difference of about 2,000 m/sec and 1,500 m/sec with depth, respectively, while the distributions of densities had a discrepancy of about $0.35g/cm^3$ with depth. However, the results of geophysical well logs analysis were similar to the two rocks. Consequently, it is clear that these results are interpreted as a difference due to weathering rather than rock type. In particular, the RQD values showed a good correlation to geophysical well log data.