Effective periods and seismic performance of steel moment resisting frames designed for risk categories I and IV according to IBC2009          下载免费PDF全文

Seong‐Hoon Jeong  Oh‐Sung Kwon  Kwang‐Ho Lee 《地震工程与结构动力学》2015,44(9):1427-1447

In current seismic design, structures that are essential for post‐disaster recovery, and hazardous facilities are classified as risk category IV and are designed with higher importance factors and stringent drift limits. These structures are expected to perform better in an earthquake event because a larger base shear and more stringent drift limit are used. Although this provision has been in the seismic design code over the last three decades, few studies have investigated the performance of essential structures. The aim of this study is to quantify the impact of higher importance factors and stringent drift limits on the seismic performance of steel moment resisting frames. A total of 16 steel structures are designed for Los Angeles and Seattle. Different risk categories are used for the design. The effects of the risk categories on the structural periods, and thus on the seismic force demand, are investigated. A suite of inelastic time history analyses are carried out to understand the probability of exceeding a specified limit state when the structures are subjected to different levels of earthquake events. The results show that the periods of the structures in risk category IV decrease by a factor of 0.5 to 0.8, and the strengths increase by a factor of 1.5 to 3.2. Seismic fragility analysis shows that the structures in risk category IV generally satisfy the probabilistic performance objectives. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

MgO‐Based Binder for Treating Contaminated Sediments: Characteristics of Metal Stabilization and Mineral Carbonation          下载免费PDF全文

Kyung‐Yup Hwang  Jeong‐Yun Seo  Hoang Q. H. Phan  Jun‐Young Ahn  Inseong Hwang 《洁净——土壤、空气、水》2014,42(3):355-363

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Three‐dimensional modelling of controlled‐source electromagnetic surveys using an edge finite‐element method with a direct solver     

Jeong‐Sul Son  Tae Jong Lee  Hee Joon Kim  Changsoo Shin 《Geophysical Prospecting》2014,62(6):1468-1483

A fully three‐dimensional finite‐element algorithm has been developed for simulating controlled‐source electromagnetic surveys. To exploit the advantages of geometric flexibility, frequency‐domain Maxwell's equations of the secondary electric field were discretised using edge‐based finite elements while the primary field was calculated analytically for a horizontally layered‐earth model. The resulting system of equations for the secondary field was solved using a parallel version of direct solvers. The accuracy of the algorithm was successfully verified by comparisons with integral‐equations and iterative solutions, and the applicability to models containing large conductivity contrasts was verified against published data. The advantages of geometry‐conforming meshes have been demonstrated by comparing different mesh systems to simulate an inclined sheet model. A comparison of the performance between direct and iterative solvers demonstrated the superior efficiency of direct solvers, particularly for multisource problems.  相似文献   

Timeline analysis and wavelet multiscale analysis of the AKARI All-Sky Survey at 90 μm     

Lingyu Wang  Michael Rowan-Robinson  Issei Yamamura  Hiroshi Shibai  Rich Savage  Seb Oliver  Matthew Thomson  Nurur Rahman  Dave Clements  Elysandra Figueredo  Tomotsugu Goto  Sunao Hasegawa  Woong-Seob Jeong  Shuji Matsuura  Thomas G. Müller  Takao Nakagawa  Chris P. Pearson  Stephen Serjeant  Mai Shirahata  Glenn J. White 《Monthly notices of the Royal Astronomical Society》2008,387(2):601-615

We present a careful analysis of the point-source detection limit of the AKARI All-Sky Survey in the WIDE-S 90-μm band near the North Ecliptic Pole (NEP). Timeline analysis is used to detect IRAS ( Infrared Astronomy Satellite ) sources and then a conversion factor is derived to transform the peak timeline signal to the interpolated 90-μm flux of a source. Combined with a robust noise measurement, the point-source flux detection limit at signal-to-noise ratio  (S/N) > 5  for a single detector row is  1.1 ± 0.1 Jy  which corresponds to a point-source detection limit of the survey of ∼0.4 Jy.
Wavelet transform offers a multiscale representation of the Time Series Data ( tsd ). We calculate the continuous wavelet transform of the tsd and then search for significant wavelet coefficients considered as potential source detections. To discriminate real sources from spurious or moving objects, only sources with confirmation are selected. In our multiscale analysis, IRAS sources selected above 4σ can be identified as the only real sources at the Point Source Scales. We also investigate the correlation between the non- IRAS sources detected in timeline analysis and cirrus emission using wavelet transform and contour plots of wavelet power spectrum. It is shown that the non- IRAS sources are most likely to be caused by excessive noise over a large range of spatial scales rather than real extended structures such as cirrus clouds.  相似文献   

Provincialism and Nd-isotopic Composition of the Late Cambrian Conodonts from the Joseon Supergroup, Korea: Implications for Paleogeography     

Yong Lee  Heon Jeong 《Gondwana Research》1999,2(4):583-585

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A subagging regression method for estimating the qualitative and quantitative state of groundwater     

Jina Jeong  Eungyu Park  Weon Shik Han  Kue-Young Kim 《Hydrogeology Journal》2017,25(5):1491-1500

A subsample aggregating (subagging) regression (SBR) method for the analysis of groundwater data pertaining to trend-estimation-associated uncertainty is proposed. The SBR method is validated against synthetic data competitively with other conventional robust and non-robust methods. From the results, it is verified that the estimation accuracies of the SBR method are consistent and superior to those of other methods, and the uncertainties are reasonably estimated; the others have no uncertainty analysis option. To validate further, actual groundwater data are employed and analyzed comparatively with Gaussian process regression (GPR). For all cases, the trend and the associated uncertainties are reasonably estimated by both SBR and GPR regardless of Gaussian or non-Gaussian skewed data. However, it is expected that GPR has a limitation in applications to severely corrupted data by outliers owing to its non-robustness. From the implementations, it is determined that the SBR method has the potential to be further developed as an effective tool of anomaly detection or outlier identification in groundwater state data such as the groundwater level and contaminant concentration.  相似文献   

Design of a low-cost attitude determination GPS/INS integrated navigation system   总被引：3，自引：2，他引：3  

Dong-Hwan Hwang  Sang Heon Oh  Sang Jeong Lee  Chansik Park  Chris Rizos 《GPS Solutions》2005,9(4):294-311

Due to their complementary features of GPS and INS, the GPS/INS integrated navigation system is increasingly being used for a variety of commercial and military applications. An attitude determination GPS (ADGPS) receiver, with multiple antennas, can be more effectively integrated with a low-cost IMU since the receiver gives not only position and velocity data but also attitude data. This paper proposes a low-cost attitude determination GPS/INS integrated navigation system. The proposed navigation system comprises an ADGPS receiver, a navigation computer unit (NCU), and a low-cost commercial MEMS IMU. The navigation software includes a fault detection and isolation (FDI) algorithm for integrity. In order to evaluate the performance of the proposed navigation system, two flight tests have been performed using a small aircraft. The first flight test confirmed the fundamental operation of the proposed navigation system and the effectiveness of the FDI algorithm. The second flight test evaluated the performance of the proposed navigation system and demonstrated the benefit of GPS attitude information in a high dynamic environment. The flight test results show that the proposed ADGPS/INS integrated navigation unit gives reliable navigation performance even when anomalous GPS data is provided and gives better navigation performance than a conventional GPS/INS unit.  相似文献   

韩国Hadong-Sanchung地区斜长岩Sr-Nd同位素初步研究——成因和前寒武纪构造意义     

郑址昆 《岩石矿物学杂志》2005,24(5):431-437

斜长岩呈长条带出露于朝鲜半岛南部,侵入到年代约为2.0Ga的Yeongnam前寒武纪基底岩石中,虽然岩石类型简单(斜长岩和辉长岩质斜长岩),但可以同世界已知块状类型斜长岩相对比。这些斜长岩具有几个重要的差别,例如呈层状构造,镁铁相成分是角闪石而不是辉石,并且不具斜方辉石巨晶。应用Rb-Sr和Sm-Nd同位素系统研究这些岩石的年龄和成因,测定出一种页理化辉长岩质斜长岩矿物的Sm-Nd等时线年龄为1678±90Ma,推断其为侵位年龄,因为中生代绿岩相变质期间这些岩石的Sm-Nd同位素体系呈封闭状态。这一年龄和过去曾报道的元古宙块状斜长岩的年龄范围(1.1~1.7Ga)相吻合。认为斜长岩成因可以用所谓元古宙斜长岩事件来解释。斜长岩的岩浆活动对朝鲜半岛南部前寒武纪基底岩石的构造历史有重要意义。全岩εNd(t)值范围-1.6~-5.2,而87Sr/86Sr初始值变化于0.704~0.706之间,据此可解释地幔成因的斜长岩岩浆是在其结晶作用期间吸收了地壳物质的结果。然而不能排除是下地壳源的可能性。  相似文献   

Mineralogy and geochemistry of metalliferous black slates in the okcheon metamorphic belt, Korea: a metamorphic analogue of black shales in the South China block     

Gi Young Jeong 《Mineralium Deposita》2006,41(5):469-481

Metalliferous black slates, which were locally exploited for their low-quality coal, are distributed in the Late Proterozoic to Paleozoic Okcheon Metamorphic Belt (OMB) of the Korean Peninsula. The mineralogy of the fine matrix is dominated by either quartz–(Ba, V)–mica–graphite or Quartz-Ba-feldspar–graphite. Polycrystalline submillimeter ellipsoids and elongate lenses aligned along foliations and veinlets are scattered through the fine matrix. Both ellipsoids and veinlets include many minor minerals containing rare elements: titanite, apatite, allanite, rutile, polycrase, barite, uraninite, xenotime, armenite, zircon, molybdenite, and sphalerite. Large graphite–apatite ellipsoids (nodules) with widths of several centimeters also occur in the highly carbonaceous black slates. Goldmanite occurs locally as porphyroblasts. The maximum rare element contents are: Ba 9.7%, V 2.04%, Mo 0.13%, U 0.11%, Cr 0.33%, Cu 254 ppm, Ni 479 ppm, Zn 607 ppm, Y 255 ppm, platinum-group element (PGE) + Au 309 ppb, and carbon 57%. The occurrence of the black slates and their elemental abundances suggests that most of the rare elements were accumulated from seawater in an oxygen-poor environment. However, the high Ba content of the OMB black slates indicates some hydrothermal input into an organic-rich basin. Although metamorphism and multiple deformations prevent a direct temporal and spatial correlation, metal abundances and a close association with graphite–apatite nodules and low-quality coal suggest that the OMB black slates are metamorphosed analogues of the Early Cambrian Ba–V deposits hosted by the black shales in the South China Block.  相似文献   

Multiple deformations along the Honam shear zone in southwestern Korea constrained by Rb–Sr dating of synkinematic fabrics: Implications for the Mesozoic tectonic evolution of northeastern Asia     

Chang-Sik Cheong  Weon-Seo Kee  Youn-Joong Jeong  Gi Young Jeong 《Lithos》2006,87(3-4):289-299

The Honam shear zone, dextrally running along the southern margin of the Ogcheon belt, Korea, has drawn much attention in reconstructing the Mesozoic tectonic framework of northeastern Asia. Here we present Rb–Sr data for the middle to southwestern part of the Honam shear zone, in an attempt to directly determine ages of deformation. In the middle part, the younger limit of deformation is constrained to be 162 ± 11 Ma by feldspar–biotite Rb–Sr dating of the deformed Sunchang granodiorite. On the other hand, an early Cretaceous deformation age is estimated for synkinematic fibers in ultramylonites from the southwestern part by two reproducible Rb–Sr errorchrons at 138 ± 4 and 139 ± 23 Ma. This deformational time scale is consistent with earlier interpretations based on field evidence, magnetic susceptibility data, and age data for Jurassic plutons within the shear zone. Our data demonstrate that the Honam shear zone is not a Permian to Triassic tectonic feature related to the Chinese continental collision.  相似文献