Artificial neural networks for predicting DGPS carrier phase and pseudorange correction   总被引：2，自引：2，他引：0  

Arif Indriyatmoko  Taesam Kang  Young Jae Lee  Gyu-In Jee  Yong Beom Cho  Jeongrae Kim 《GPS Solutions》2008,12(4):237-247

Artificial neural networks (ANNs) were used to predict the differential global positioning system (DGPS) pseudorange and carrier phase correction information. Autoregressive moving average (ARMA) and autoregressive (AR) models were bounded with neural networks to provide predictions of the correction. The neural network was employed to realize time-varying implementation. Online training for real-time prediction of the carrier phase enhances the continuity of service of the differential correction signals and, therefore, improves the positioning accuracy. When the correction signal from the DGPS was lost, the artificial neural networks predicted the correction data with good accuracy for the navigation system during a limited period. Comparisons of the prediction results using the two models are given.

Young Jae LeeEmail:

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A Platform for Visualizing and Experimenting with Measures of Semantic Similarity in Ontologies and Concept Maps     

Mark Gahegan  Ritesh Agrawal  Anuj Jaiswal  Junyan Luo  Kean‐Huat Soon 《Transactions in GIS》2008,12(6):713-732

This article describes research in the ongoing search for better semantic similarity tools: such methods are important when attempting to reconcile or integrate knowledge, or knowledge‐related resources such as ontologies and database schemas. We describe an extensible, open platform for experimenting with different measures of similarity for ontologies and concept maps. The platform is based around three different types of similarity, that we ground in cognitive principles and provide a taxonomy and structure by which new similarity methods can be integrated and used. The platform supports a variety of specific similarity methods, to which researchers can add others of their own. It also provides flexible ways to combine the results from multiple methods, and some graphic tools for visualizing and communicating multi‐part similarity scores. Details of the system, which forms part of the ConceptVista open codebase, are described, along with associated details of the interfaces by which users can add new methods, choose which methods are used and select how multiple similarity scores are aggregated. We offer this as a community resource, since many similarity methods have been proposed but there is still much confusion about which one(s) might work well for different geographical problems; hence a test environment that all can access and extend would seem to be of practical use. We also provide some examples of the platform in use.  相似文献   

Three unrecorded marine fish species from Korean waters     

Jeong -Ho Park  Jin Koo Kim  Jee Hwan Moon  Cheol Bum Kim 《Ocean Science Journal》2007,42(4):231-240

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Lateral and consolidation behaviors of seabed-type breakwater for very soft ground     

In Sung Jang  O Soon Kwon  Woo Sun Park  Weon Mu Jeong 《Ocean Engineering》2007,34(17-18):2240-2250

A seabed-type of breakwater applicable to very soft ground without the need for soil improvement is newly developed. This type of soft-ground breakwater is expected to ensure sufficient lateral resistance and prevent excessive consolidation settlement due to self-weight of the breakwater. In this paper, lateral and consolidation behaviors of soft-ground breakwater were investigated by performing model tests and finite element simulations. The results revealed that the bottom wall and buoyant box, which are the main features of soft-ground breakwater, contribute to the increase in lateral resistance and to the control of the consolidation settlements, respectively, and that Terzaghi's consolidation theory could be conservatively adopted in deriving the consolidation settlements of soft-ground breakwater proposed herein.  相似文献   

The coefficient of earth pressure at rest in hydrate-bearing sediments     

Kim  Jongchan  Seol  Yongkoo  Dai  Sheng 《Acta Geotechnica》2021,16(9):2729-2739

Acta Geotechnica - The presence of hydrate alters the stress distribution in sediments. Current analyses of stress state and stress path in hydrate deposits are simplistic, and no direct...  相似文献   

Changing stellar activity cycles     

K. Oláh  K.G. Strassmeier  T. Granzer  W. Soon  S.L. Baliunas 《Astronomische Nachrichten》2007,328(10):1072-1074

We investigated continuous long-term photometric datasets of thirteen active stars, Ca II variability of one single mainsequence star, and 10.7 cm radio data of the Sun, with simple Fourier- and time-frequency analysis. The data reflect the strength of the activity manifested in magnetic spots. All studied stars show multiple (2 to 4) cycles of different lengths. The time-frequency analysis reveals, that in several cases of the sample one or two of the cycles exhibit continuous changes (increase or decrease). For four stars (V711 Tau, IL Hya, HK Lac, HD 100180) and for the Sun we find that the cycle length changes are strong, amounting to 10–50% during the observed time intervals. The cycle lengths are generally longer for stars with longer rotational periods. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

A discontinuity in the late Pleistocene alluvial deposits,Hwacheon‐ri,Gyeongju, Korea: Occurrences and paleoenvironmental implication          下载免费PDF全文

Hoil Lee  In Sung Paik  Hyun Joo Kim  Hee‐Cheol Kang  Won Gyeong Seol  Jin‐Young Lee 《Island Arc》2018,27(4)

A sedimentary discontinuity is present in the late Pleistocene alluvial deposits exposed along the cliff in stream side, Gyeongju, Korea. Sedimentological study, Optically Stimulated Luminescence (OSL) age dating, and X‐ray diffraction (XRD), and X‐ray fluorescence spectrometer (XRF) analyses were conducted in order to interpret the origin of the discontinuity surface. Based on the sedimentological study, these deposits can be divided into three distinct stages, in ascending order: (Stage 1) development of a braided stream flowing from south to north and deposition by debris flows from the mountain aside the stream during and/or after deposition of the braided stream; (Stage 2) deposition by intermittent events during a state of stagnation after the abandonment or migration of the previously existed braided stream; and (Stage 3) deposition of gravels from debris flows from the mountain aside the stream. Hornfelsic gravels are common in Stage 1, whereas andesitic gravels are predominant in Stage 3, suggesting the provenance change from Stage 1 to Stage 3. The discontinuity surface is laterally extensive and marked by a distinct carbonaceous dark grey horizon between Stage 2 and Stage 3. It is characteristic that rootlets mineralized by vivianite are present, and iron‐oxide crusts are cutting across irregularly below the discontinuity surface. It is thus interpreted that the shift of depositional environment from an alluvial plain (Stage 2) (125 ka) to an alluvial fan (Stage 3) (94–55 ka) was an alluvial response to sea level change from the interglacial to the glacial. The development of iron‐oxide crusts and diagenetic vivianite in the discontinuity surface suggests humid condition persisted during the paleoclimatic shift from the last interglacial to the last glacial stages.  相似文献   

Flow Behavior Behind A Freely Suspended Cylinder in the Wake of A Stationary Cylinder     

Gao  Yang-yang  Chen  Wei-yi  Tan  Soon Keat  Zhang  Bao-feng 《中国海洋工程》2020,34(5):708-717

China Ocean Engineering - The experiment of flow past a freely suspended circular cylinder in the wake of an upstream stationary cylinder was carried out in a re-circulating water channel using the...  相似文献   

Are Juvenile Manila Clam Ruditapes philippinarum Free from Perkinsus olseni Infection in Korean Waters?     

Lee  Hye-Mi  Cho  Young-Ghan  Jeung  Hee-Do  Jang  Min-Seok  Hwang  Jee Youn  Choi  Kwang-Sik 《Ocean Science Journal》2020,55(4):573-579

Ocean Science Journal - As a suspension feeder, Manila clam Ruditapes philippinarum (A. Adams and Reeve 1850) plays a crucial role in the coastal soft bottom ecosystem in the temperate region,...  相似文献   

Acidification at the Surface in the East Sea: A Coupled Climate-carbon Cycle Model Study     

Young-Gyu Park  Kyung-Hee Seol  Kyung-On Boo  Johan Lee  Chunho Cho  Young-Hwa Byun  Seongbong Seo 《Ocean Science Journal》2018,53(3):437-448

This modeling study investigates the impacts of increasing atmospheric CO₂ concentration on acidification in the East Sea. A historical simulation for the past three decades (1980 to 2010) was performed using the Hadley Centre Global Environmental Model (version 2), a coupled climate model with atmospheric, terrestrial and ocean cycles. As the atmospheric CO₂ concentration increased, acidification progressed in the surface waters of the marginal sea. The acidification was similar in magnitude to observations and models of acidification in the global ocean. However, in the global ocean, the acidification appears to be due to increased in-situ oceanic CO₂ uptake, whereas local processes had stronger effects in the East Sea. pH was lowered by surface warming and by the influx of water with higher dissolved inorganic carbon (DIC) from the northwestern Pacific. Due to the enhanced advection of DIC, the partial pressure of CO₂ increased faster than in the overlying air; consequently, the in-situ oceanic uptake of CO₂ decreased.  相似文献