An object-oriented knowledge representation structure for exploration data integration     

P. An  W. M. Moon  G. F. Bonham-Carter 《Natural Resources Research》1994,3(2):132-145

Knowledge representation structure and reasoning processes are very important issues in the knowledge-based approach of integrating multiple spatial data sets for resource exploration. An object-oriented knowledge representation structure and corresponding reasoning processes are formulated and tested in this research on the knowledge-based approach of integrating spatial exploration data. The map-based prototype expert system developed in this study has self-contained knowledge representation structure and inference mechanisms. It is important to distinguish between lack of information and information providing negative evidence for a map-based system because the spatial distribution of data sets are uneven in most cases. Error and uncertainty estimation is also an important component of any production expert system. The uncertainty propagation mechanisms developed here work well for this type of integrated exploration problem. Evidential bellef function theory provides a natural theoretical basis for representing and integrating spatially uneven geophysical and geological information. The prototype system is tested using real mineral exploration data sets from the Snow Lake area, northern Manitoba, Canada. The test results outline the favorable exploration areas successfully and show the effectiveness of the knowledge representation structure and inference mechanisms for the knowledge-based approach.  相似文献   

Sediment yield in South Africa — A preliminary geographical analysis     

Kim Boucher  Alex van Breda Weaver Dr. 《GeoJournal》1991,23(1):7-17

The study examines the spatial relationships between sediment yield and 15 independent environmental variables in 54 catchments in South Africa. Rooseboom's (1978) data on the sediment yield from the catchments were standardized for a single time period. Bivariate regression analyses reveal no simple relationships. Multivariate regression analyses conducted for the whole and various sub-areas of South Africa indicate that latitude and longitude are the primary variables affecting spatial variations in sediment yield. This may be as a result of latitude and longitude being surrogate variables reflecting variation in other environmental variables (e. g. geology, vegetation). Within the sub-areas, 43.4% to 97.8% of the variation in sediment yield is explained by the combined variation in a number of different environmental variables. This study highlights a need for the collection and analysis of more sediment yield data, which would allow the analyses to be refined, to predict sediment yields from ungauged catchments in South Africa.  相似文献   

Radial growth rates and Pb ages of hydrothermal massive sulfides from the Juan de Fuca Ridge     

Kim Hyun Kim  Gary M. McMurtry 《Earth and Planetary Science Letters》1991,104(2-4)

Activities of ²³⁸U, ²²⁸Ra, ²²⁶Ra and ²¹⁰Pb were determined in submarine hydrothermal massive sulfides by nondestructive, gamma-ray spectrometry. The samples were collected by the manned submersible DSRV “Alvin” from active hydrothermal fields on the Endeavour Segment and Axial Seamount of the Juan de Fuca Ridge. ²¹⁰Pb activities are mostly below the equilibrium level with ²²⁶Ra, which is linearly correlated with the concentration of Ba, Sr and Ca in the deposits. The ratios of²²⁶Ra to the alkaline earth elements indicate that hydrothermal alteration of the underlying oceanic crust is the dominant source of Ra in the sulfide deposits.The ²¹⁰Pb/Pb ratios measured in many of the sulfides are higher than the ratio obtained for a basalt source of ²¹⁰Pb, probably because of ²¹⁰Pb ingrowth from ²²⁶Ra within the sulfide deposits. An isochron approach employing ratios of ²¹⁰Pb/Pb and ²²⁶Ra/Pb yielded an initial ²¹⁰Pb/Pb ratio in the range of 0–0.57 dpm/μg Pb, implying that the crustal residence time of the hydrothermal fluid in the Endeavour Segment is very short ( < 10 years) and that basalt alteration is the only source of the ²¹⁰Pb and Pb. For the hydrothermal fluid in Axial Seamount, a residence time of 10–20 years is estimated on the basis of the initial ²¹⁰Pb/Pb and ²²⁸Ra/²²⁶Ra ratios of a sulfide chimney. Both residence time estimates are consistent with the results of previous studies. We have estimated the upper limits of sample ages ranging from tens to a hundred years for 12 samples, with the remaining seven samples indicating ages close to or older than 150 years, the practical limit of the ²¹⁰Pb/Pb dating technique.A concentrically sectioned sulfide chimney from Axial Seamount yielded mean radial growth rates ranging from a few tenths to a few mm/year based on gradients of ²¹⁰Pb/Pb and ²²⁸Ra/²²⁶Ra activity ratios, whereas a similarly sectioned chimney from the Endeavour Segment, although collected from the top of an active “black smoker” vent, displayed no ²¹⁰Pb or ²²⁸Ra activity. Our results have implications for the duration and periodicity of hydrothermal circulation and associated mineral deposition at mid-ocean ridges.  相似文献   

用超速CT机检测99例无症状香港中国人降低钙指数     

吴敬文  戴有鼎 《CT理论与应用研究》1994,3(4):34-34

回顾分析Ｍａｔｉｌｄａ医院超速ＣＴ室筛选首批病人中９９例中国人资料，很明显从通常采用１３０－１００Ｈｏｕｎｓｆｉｅｌｄ单位作为检出冠状血管钙化的基数应用至中国人身上其阈值数目需要降低，同时，我们也发现如果病人年龄按每１０年范围分组（２１－３０，３０－４０，４１－５０，５１－６０）而计算其超速ＣＴ的钙化指数会较随机男女一起按平均计算更易区分其差异．进一步分析显示，男性中年时候超速ＣＴ指数已达最高值，而女性则晚１０年方达最高值，因此，为了更易探测冠脉循环内钙化倾向应作出超速ＣＴ检出钙化的指数数目．这些实践经验对动脉粥样硬化过程的预测或预防有实际意义．  相似文献   

Getting Personal: Reflexivity,Positionality, and Feminist Research*   总被引：1，自引：1，他引：1  

Kim V. L. England 《The Professional geographer》1994,46(1):80-89

Feminist and poststructural challenges to objectivist social science demand greater reflection by the researcher with the aim of producing more inclusive methods sensitive to the power relations in fieldwork. Following a discussion of contrasting approaches to these power relations, I present a reflexive examination of a research project on sexual identities. My reflections highlight some of the key ethical questions that face researchers conducting fieldwork, especially with regard to the relationship between the researcher and those being researched. My discussion of these dilemmas reflect the situated and partial nature of our understanding of “others.” I argue that the researcher's positionality and biography directly affect fieldwork and that fieldwork is a dialogical process which is structured by the researcher and the participants.  相似文献   

Plutonic inclusions and olivines in high-K volcanics from Ulreung island,Korea     

Yoon Kyu Kim  Hirokazu Fujimaki 《Mineralogy and Petrology》1987,37(2):117-136

Summary Major and trace element data are presented for four alkali gabbroic inclusions, two monzonitic inclusions, and nine syenitic inclusions from Ulreung island, Korea. Analytical results are also given for the mineral constituents. Although the major element chemistry suggests that the plutonic inclusions are comagmatic with the associated volcanic rocks, the trace element data demonstrate that they do not represent a simple liquid line of descent. In addition, the mineralogical data indicate that they are not likely to represent cumulates on the floor of the magma chamber from which the observed volcanic rocks have been derived. Titanbiotite crystallization preceded kaersutite crystallization in the plutonic rocks but that order was inverse in the volcanic rocks. The trachytic-phonolitic rocks contain Fe-rich olivine phenocrysts, whereas the plutonic inclusions do not. These discrepancies can be accounted for by the assumption that the investigated plutonic rocks represent some cumulus parts of intrusive bodies solidified at shallower depth than the magma reservoir beneath the island. Petrographic features of the gabbroic inclusions are suggestive that olivine was probably in a reaction relationship with liquid to form titanbiotite. Comparison with petrological data of the volcanic rocks also implies that olivine was in a reaction relationship with an intermediate alkalic magma in both the intruded magmas at shallow depth and in the magma chamber at great depth. This is the cause of the olivine compositional gap in the high-K volcanic suite. Titanbiotite is a major reaction product.

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Plutonische Einschlüsse und Olivine in Kalium-reichen Vulkaniten von Ulreung Island, Korea

Zusammenfassung Haupt- und Spurenelementdaten von vier alkalischen gabbroiden, zwei monzonitische Haupt- und Spurenelementdaten von vier alkalischen gabbroiden, zwei monzonitische und neun syenitischen Einschlüssen von Ulreung Island, Korea, sowie analytische Daten der Mineralkomponenten werden vorgelegt. Obwohl der Hauptelementchemismus andeutet, daß die plutonischen Intrusionen und die vergesellschafteten vulkanischen Gesteine comagmatisch sind, zeigen die Spurenelementdaten, daß diese nicht eine einfache Magmenlinie darstellen. Außerdem zeigen die mineralogischen Daten an, daß die Gesteine wahrscheinlich keine Kumulate vom Boden der Magmenkammer sind, von welcher die beobachteten vulkanischen Gesteine herstammen. In den plutonischen Gesteinen kristallisierte Titan-Biotit früher als der Kaersutit. In den vulkanischen Gesteinen ist diese Reihenfolge jedoch umgekehrt. Die trachitischen/phonolitischen Gesteine enthalten im Gegensatz zu den plutonischen Einschlüssen Fe-reiche Olivin-Phenokrysten. Diese Unterschiede können durch die Annahme erklärt werden, daß die untersuchten plutonischen Gesteine bestimmte Kumulate eines intrusiven Körpers sind, der in geringerer Tiefe als das Magmenreservoir unterhalb der Inseln erstarrte. Petrographische Kennzeichen von gabbroischen Einschlüssen deuten darauf hin, daß der Olivin wahrscheinlich mit der Schmelze reagiert hat und Titan-Biotit bildete. Ein Vergleich der petrographischen Daten der vulkanischen Gesteine Vergleich der petrographischen Daten der vulkanischen Gesteine läßt ebenfalls den Schluß zu, daß Olivin mit einem intermediären alkalischen Magma in beiden, dem intrudierten Magma in geringer Tiefe und der Magmakammer in großer Tiefe, reagierte. Dies ist der Grund für die Lücke in der Olivinzusammensetzung in der Kalium-reichen vulkanischen Suite. Titan-Biotit ist ein Hauptreaktionsprodukt.

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With 9 Figures  相似文献   

The difference in chemical composition of the 1962 lava from miyakezima magma reservoir in Japan     

I. Iwasaki  T. Ozawa  M. Yoshida  T. Katsura  Chan Kuk Kim  M. Aoyagi  Y. Yoshiike 《Bulletin of Volcanology》1982,45(2):81-85

Many examples of mixed magmas in banded lavas have been studied. Another type of mixed magmas or inhomogeneity of magma reservoir found in the 1962 lava flows of Miyake-zima Volcano erupted from fissures is reported.  相似文献   

Risk Management for Petroleum Reservoir Production: A Simulation-Based Study of Prediction     

James Glimm  Shuling Hou  Hongjoong Kim  Yoon-ha Lee  David H. Sharp  Kenny Ye  Qisu Zou 《Computational Geosciences》2001,5(3):173-197

We consider numerical solutions of the Darcy and Buckley–Leverett equations for flow in porous media. These solutions depend on a realization of a random field that describes the reservoir permeability. The main content of this paper is to formulate and analyze a probability model for the numerical coarse grid solution error. We explore the extent to which the coarse grid oil production rate is sufficient to predict future oil production rates. We find that very early oil production data is sufficient to reduce the prediction error in oil production by about 30%, relative to the prior probability prediction.  相似文献   

Improved magnetic anomalies of the Antarctic lithosphere from satellite and near-surface data     

Hyung Rae Kim  Ralph R. B. von Frese  Patrick T. Taylor  Alexander V. Golynsky  Luis R. Gaya-Piqué  Fausto Ferraccioli 《Geophysical Journal International》2007,171(1):119-126

The Antarctic magnetic anomaly map compiled marine and airborne surveys collected south of 60°S through 1999 and used Magsat data to help fill in the regional gaps between the surveys. Ørsted and CHAMP satellite magnetic observations with greatly improved measurement accuracies and temporal and spatial coverage of the Antarctic, have now supplanted the Magsat data. We combined the new satellite observations with the near-surface survey data for an improved magnetic anomaly map of the Antarctic lithosphere. Specifically, we separated the crustal from the core and external field components in the satellite data using crustal thickness variations estimated from the terrain and the satellite-derived free-air gravity observations. Regional gaps in the near-surface surveys were then filled with predictions from crustal magnetization models that jointly satisfied the near-surface and satellite crustal anomalies. Comparisons in some of the regional gaps that also considered newly acquired aeromagnetic data demonstrated the enhanced anomaly estimation capabilities of the predictions over those from conventional minimum curvature and spherical harmonic geomagnetic field models. We also noted that the growing number of regional and world magnetic survey compilations involve coverage gaps where these procedures can contribute effective near-surface crustal anomaly estimates.  相似文献   

Allocating local groundwater monitoring stations for South Korea using an analytic hierarchy process   总被引：1，自引：1，他引：1  

Jeong-Woo Kim  Jin-Yong Lee  Myeong-Jae Yi  Gyoo-Bum Kim  Jong-Ho Won  Kang-Kun Lee 《Hydrogeology Journal》2007,15(3):615-632

A national groundwater-monitoring network consisting of 320 stations has been operated by the Ministry of Construction and Transportation and the Korea Water Resources Corporation since 1995. The network was established as a result of the Groundwater Act of Korea, and a supplementary local groundwater monitoring network containing 10,000 stations will be established throughout the country by the year 2011. A method of allocating stations and organizing the local monitoring network has been developed, based on the analytic hierarchy process (AHP), using pairwise comparison. Several evaluation criteria were selected for determining the required number of the monitoring stations at specific local districts. Weights of the selected criteria were assigned by the pairwise comparison, reflecting hydrogeological conditions and supported by pertinent questions to 93 groundwater experts. To evaluate appropriateness of this method, an example city, Jeonju, was selected where groundwater levels were monitored; seven stations were determined as to be required for the supplementary groundwater-monitoring network. The study demonstrated the usefulness of the AHP. The concepts of the development and the structure of the AHP model can be applied to site or well selections within a particular district.  相似文献