Reproducibility of a regional geological map derived from geochemical maps, using data mining techniques: with application to Chungbuk province of Korea   总被引：1，自引：0，他引：1  

SangGi Hwang  QuocPhi Nguyen  PyeongKoo Lee 《Environmental Geology》2005,48(4-5):569-578

Interpolated geochemical maps contain problems of sample catchments and vacant sample areas. However, the resemblance of these maps with regional geological maps implies that there are strong correlations between them. A conceptual model of the geological units from multivariate chemical elements is constructed by decision tree technique. The reproducibility of the geological map with the conceptual model is about 80% in the Chungbuk province map of Korea. Statistical uncertainties indicate that rock units could be predicted reasonably well by decision tree if the geological map polygon is big enough. Misinterpreted points are due to interpolation problems between samples from adjacent rock units and from different sample catchments. In the Chungbuk example, the latter is less significant. The size of the map polygon is one of the most critical factors, and a polygon size greater than 50 km² is reliable for such analyses for the Chungbuk example. Combined lithologies in a single mapping unit are not critically affected by decision tree prediction.  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   

A seismic retrofit method by connecting viscous dampers for microelectronics factories     

Jenn‐Shin Hwang  Shiang‐Jung Wang  Yin‐Nan Huang  Jay‐Fu Chen 《地震工程与结构动力学》2007,36(11):1461-1480

The implementation of viscous dampers to microelectronics factories has been previously proved not to affect the micro‐vibration of the factories in operation so that the vibration‐sensitive manufacturing process will not be interfered. Therefore, a seismic retrofit strategy which employs the viscous dampers installed in between the exterior and interior structures of the ‘fab’ structure is proposed in the study. The design formulas corresponding to the proposed retrofit method are derived using the non‐proportional damping theory. Based on the study, it is found that the added damping ratio to the fab structure depends greatly on the frequency ratio of the two structures in addition to the damping coefficients of the added dampers. Outside the bandwidth of the frequency ratio in which the added damping ratio is very sensitive to the variation of the frequency ratio, the added damping ratio can be well captured using the classical damping theory. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Two new records of Valenciennea helsdingenii (Perciformes: Gobiidae) and Chromis margaritifer (Perciformes: Pomacentridae) from Jeju Island,Korea     

Jung-Goo Myoung  Se Hun Myoung  In-Seo Hwang  Byung-il Kim  Jin-Koo Kim 《Ocean Science Journal》2014,49(1):19-24

Two specimens of Valenciennea helsdingenii and one specimen of Chromis margaritifer were collected on scuba in October 2011 from Jeju Island, Korea. V. helsdingenii is characterized by a body with two dark stripes that connect the head and caudal fin, and a large dark spot between the third and sixth dorsal fin spines. C. margaritifer is characterized by a body that is dark brown anteriorly but white posteriorly at the boundary between the fifth dorsal fin soft ray and the ninth anal fin soft ray. The Korean name ‘Bok-gi-mang-duk-sok’ is proposed for the genus Valenciennea, the name ‘Du-jul-bok-gi-mang-duk’ is proposed for the species V. helsdingenii, and the name ‘Huinggo-ri-ja-ri-dom’ is proposed for C. margaritifer.  相似文献   

Assessing antenna field of view and receiver clocks of COSMIC and GRACE satellites: lessons for COSMIC-2     

Tzu-Pang Tseng  Kefei Zhang  Cheinway Hwang  Urs Hugentobler  Chuan-Sheng Wang  Suelynn Choy  Yi-Shan Li 《GPS Solutions》2014,18(2):219-230

We provide suggestions for the approved COSMIC-2 satellite mission regarding the field of view (FOV) and the clock stability of its future GNSS receiver based on numerical analyses using COSMIC GPS data. While the GRACE GPS receiver is mounted on the zenith direction, the precise orbit determination (POD) antennas of COSMIC are not. The COSMIC antenna design results in a narrow FOV and a reduction in the number of GPS observations. To strengthen the GPS geometry, GPS data from two POD antennas of COSMIC are used to estimate its orbits. The phase residuals of COSMIC are at the centimeter level, compared to the millimeter level of GRACE. The receiver clock corrections of COSMIC and GRACE are at the microsecond and nanosecond levels, respectively. The clock spectra of COSMIC at the frequencies of 0–0.005 Hz contain significant powers, indicating potential systematic errors in its clock corrections. The clock stability, expressed by the Allan deviation, of COSMIC ranges from 10^?9 to 10^?11 over 1 to 10⁴ s, compared to 10^?12 to 10^?14 for GRACE. Compared to USO-based clock of GRACE, the clock of COSMIC is degraded in its stability and is linked to the reduction of GPS data quality. Lessons for improvement of COSMIC-2 over COSMIC in FOV and receiver clock stability are given.  相似文献   

Marine environmental impact assessment of abalone,Haliotis discus hannai,cage farm in Wan-do,Republic of Korea     

Hyun-Taik Oh  Rae-Hong Jung  Yoon-Sik Cho  Dong-Woon Hwang  Yong-Min Yi 《Ocean Science Journal》2015,50(4):657-667

To assess the marine environmental impacts of abalone, Haliotis discus hannai, cage farms in Wan-do, we monitored the benthic environment on top of the sediment underneath cage farm stations and reference stations. We applied two methods for this assessment. One was the A- and B-investigation of the MOM system (Modeling–On fish farm–Monitoring) developed in Norway. The other was a general environmental monitoring method which is widely used. In this study, we found benthic animals in all samples that belonged to condition 1 which were based on group 1(presence of macrofauna) of the B-investigation method. The values of redox potential (group 2–pH, redox potential) in all samples were above +65 mV belonging to condition 1. Based on sensory results (group 3–gas, color, odor, thickness of deposits), five out of seven experiment samples showed condition 1 while stations 2 and 7 showed condition 2, which have been cultured for 10 years in semi-closed waters. As group 2 takes precedence over group 3, the level of the conditions for B-investigation results consequently showed condition 1 in all stations. We found that pollutants and trace metals in the sediment underneath cage farms were lower than the pollution standard. This led us to conclude that the environmental impacts of the cage farms in this study were not significant.  相似文献   

A Bathymetric Model for the South China Sea from Satellite Altimetry and Depth Data   总被引：8，自引：0，他引：8  

Cheinway Hwang 《Marine Geodesy》1999,22(1):37-51

A bathymetric model for the South China Sea is computed from altimeter-derived gravity anomalies, shipborne depths, ETOPO5, and the GMT shorelines using a procedure that includes downward continuation, linear regression, and data merging. The model best fits the GMT shorelines and is a compromise between smoothness, degree of agreement with ship data, and the seafloor features we wish to retain. The model is proven useful in studying the tectonics and modeling the ocean tide of the South China Sea.  相似文献   

A self‐organization algorithm for real‐time flood forecast     

Fi‐John Chang  Yuan‐Yih Hwang 《水文研究》1999,13(2):123-138

The group method of data handling (GMDH) algorithm presented by A. C. Ivakhnenko and colleagues is an heuristic self‐organization method. It establishes the input–output relationship of a complex system using a multilayered perception‐type structure that is similar to a feed‐forward multilayer neural network. This study provides a step towards understanding and evaluating a role for GMDH in the investigation of the complex rainfall–runoff processes in a heterogeneous watershed in Taiwan. Two versions of the revised GMDH model are implemented: a stepwise regression procedure and a recursive formula. Eleven typhoon events in the Shen‐cei Creek watershed, Taiwan, are used to build the model and verify its usefulness. The prediction results of the revised GMDH models and the instantaneous unit hydrograph (IUH) model are compared. Based on the criteria of forecasting precision and the rate and time of peak error, a much better performance is obtained with the revised GMDH models. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

Liquefaction,building settlement,and residual strength of two residential areas during the 2016 southern Taiwan earthquake     

Tsai  Chi-Chin  Hwang  Yu-Wei  Lu  Chih-Chieh 《Acta Geotechnica》2020,15(6):1363-1379

Acta Geotechnica - On February 6, 2016, a moment magnitude (Mw) 6.4 earthquake struck southern Taiwan and devastated the Tainan area. Although the intensity of ground shaking was only moderate...  相似文献   

Magnetotail dipolarization fronts and particle acceleration: A review     

Fu  Huishan  Grigorenko  Elena E.  Gabrielse  Christine  Liu  Chengming  Lu  San  Hwang  K. J.  Zhou  Xuzhi  Wang  Zhe  Chen  Fang 《中国科学:地球科学(英文版)》2020,63(2):235-256

In this paper, the particle acceleration processes around magnetotail dipolarization fronts(DFs) were reviewed. We summarize the spacecraft observations(including Cluster, THEMIS, MMS) and numerical simulations(including MHD, testparticle, hybrid, LSK, PIC) of these processes. Specifically, we(1) introduce the properties of DFs at MHD scale, ion scale, and electron scale,(2) review the properties of suprathermal electrons with particular focus on the pitch-angle distributions,(3)define the particle-acceleration process and distinguish it from the particle-heating process,(4) identify the particle-acceleration process from spacecraft measurements of energy fluxes, and(5) quantify the acceleration efficiency and compare it with other processes in the magnetosphere(e.g., magnetic reconnection and radiation-belt acceleration processes). We focus on both the acceleration of electrons and ions(including light ions and heavy ions). Regarding electron acceleration, we introduce Fermi,betatron, and non-adiabatic acceleration mechanisms;regarding ion acceleration, we present Fermi, betatron, reflection, resonance, and non-adiabatic acceleration mechanisms. We also discuss the unsolved problems and open questions relevant to this topic, and suggest directions for future studies.  相似文献