The Sinusoidal Projection: A New Importance in Relation to Global Image Data     

Jeong Chang Seong  Karen A. Mulcahy  E. Lynn Usery 《The Professional geographer》2002,54(2):218-225

The reprojection of image data causes the loss or duplication of original pixel values. This research investigated the feasibility of using the sinusoidal projection for global image database construction. Specifically, reprojection accuracies were tested with geographic latitude and longitude coordinates, and the Hammer‐Aitoff, Eckert IV, Mollweide, and sinusoidal projections. Reprojections between these five global projections and the Universal Transverse Mercator (UTM) projection and referencing system were performed using fifty‐four sample datasets. A statistical analysis of categorical accuracy, a measure describing the omission of pixel values during reprojection, was conducted. Geographic coordinates and the sinusoidal projection both showed very high accuracy rates (100.0 percent and 99.5 percent respectively) when sample datasets were reprojected from UTM. The geographic coordinates, however, showed very low accuracy (65.3 percent) when sample datasets were reprojected to the UTM projection, while the sinusoidal projection showed the highest accuracy (98.4 percent). The results strongly suggest that the sinusoidal projection is very accurate and efficient for building global image databases.  相似文献   

Recurrent events on a Quaternary fault recorded in the mineralogy and micromorphology of a weathering profile, Yangsan Fault System, Korea   总被引：1，自引：0，他引：1  

Gi Young Jeong  Chang-Sik Cheong 《Quaternary Research》2005,64(2):221-233

Recurrence characteristics of a Quaternary fault are generally investigated on the basis of field properties that are rapidly degraded by chemical weathering and erosion in warm humid climates. Here we show that in intense weathering environments, mineralogical and micromorphological investigations are valuable in paleoseismological reconstruction. A weathering profile developed in Late Quaternary marine terrace deposits along the southeastern coast of the Korean Peninsula was disturbed by tectonic movement that appears to be a simple one-time reverse faulting event based on field observations. A comparative analysis of the mineralogy, micromorphology, and chemistry of the weathering profile and fault gouge, however, reveals that both the microfissures in the deformed weathering profile and larger void spaces along the fault plane were filled with multi-stage accumulations of illuvial clay and silt minerals of detrital origin, suggesting a repetition of fissuring and subsequent sealing in the weathering profile as it underwent continuous mineralogical transformation and particle translocation. We reconstruct a sequence of multiple faulting events unrecognized in previous field surveys, which requires revision of the view that the Korean Peninsula was tectonically stable, during the Late Quaternary.  相似文献   

An Experimental Performance Evaluation of Spatio-Temporal Join Strategies   总被引：1，自引：0，他引：1  

Seung-Hyun Jeong  Norman W. Paton  Alvaro A. A. Fernandes  Tony Griffiths 《Transactions in GIS》2005,9(2):129-156

Many applications capture, or make use of, spatial data that changes over time. This requirement for effective and efficient spatio‐temporal data management has given rise to a range of research activities relating to spatio‐temporal data management. Such work has sought to understand, for example, the requirements of different categories of application, and the modelling facilities that are most effective for these applications. However, at present, there are few systems with fully integrated support for spatio‐temporal data, and thus developers must often construct custom solutions for their applications. Developers of both bespoke solutions and of generic spatio‐temporal platforms will often need to support the fusion of large spatio‐temporal data sets. Supporting such requests in a database setting involves the use of join operations with both spatial and temporal conditions – spatio‐temporal joins. However, there has been little work to date on spatio‐temporal join algorithms or their evaluation. This paper presents an evaluation of several approaches to the implementation of spatio‐temporal joins that build upon widely available indexing techniques. The evaluation explores how several algorithms perform for databases with different spatial and temporal characteristics, with a view to helping developers of generic infrastructures or custom solutions in the selection and development of appropriate spatio‐temporal join strategies.  相似文献   

The effect of earthquake duration on the damage of structures     

Garrett D. Jeong  Wilfred D. Iwan 《地震工程与结构动力学》1988,16(8):1201-1211

This paper presents a theoretical analysis of the effect of duration on the damage of structures subjected to earthquakes. The earthquake excitation is modelled by a non-stationary random process whose response spectrum is probabilistically consistent with a design response spectrum specified independently of the duration. Damage is assumed to accumulate with the cyclic application of large strains in the structural members. Two types of structure are examined: one representative of a steel structure and the other reprsentative of a reinforced concrete structure. The level of expected damage is found to be a strong function of both the ductility of the response and the duration of the excitation. Results are presented for systems with linear stiffness and a particular form of softening behaviour.  相似文献   

Spatial and temporal variations of spatial population accessibility to public hospitals: a case study of rural–urban comparison     

Yongze Song  Yi Tan  Yimeng Song  Peng Wu  Jack C.P Cheng  Mi Jeong Kim 《地理信息系统科学与遥感》2018,55(5):718-744

Quantification and assessment of nationwide population access to health-care services is a critical undertaking for improving population health and optimizing the performance of national health systems. Rural–urban unbalance of population access to health-care services is widely involved in most of the nations. This unbalance is also potentially affected by varied weather and road conditions. This study investigates the rural and urban performances of public health system by quantifying the spatiotemporal variations of accessibility and assessing the impacts of potential factors. Australian health-care system is used as a case study for the rural–urban comparison of population accessibility. A nationwide travel time-based modified kernel density two-step floating catchment area (MKD2SFCA) model is utilized to compute accessibility of travel time within 30, 60, 120, and 240 min to all public hospitals, hospitals that provide emergency care, and hospitals that provide surgery service, respectively. Results show that accessibility is varied both temporally and spatially, and the rural–urban unbalance is distinct for different types of hospitals. In Australia, from the perspective of spatial distributions of health-care resources, spatial accessibility to all public hospitals in remote and very remote areas is not lower (and may even higher) than that in major cities, but the accessibility to hospitals that provide emergency and surgery services is much higher in major cities than other areas. From the angle of temporal variation of accessibility to public hospitals, reduction of traffic speed is 1.00–3.57% due to precipitation and heavy rain, but it leads to 18–23% and 31–50% of reduction of accessibility in hot-spot and cold-spot regions, respectively, and the impact is severe in New South Wales, Queensland, and Northern Territory during wet seasons. Spatiotemporal analysis for the variations of accessibility can provide quantitative and accurate evidence for geographically local and dynamic strategies of allocation decision-making of medical resources and optimizing health-care systems both locally and nationally.  相似文献   

Development of a natural analogue database to support the safety case of the Korean radioactive waste disposal program     

Min Hoon Baik  Tae-Jin Park  In Young Kim  Jongtae Jeong  Kyung Woo Choi 《Swiss Journal of Geoscience》2015,108(1):139-146

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Interdecadal change of interannual variability and predictability of two types of ENSO     

Hye-In Jeong  Joong-Bae Ahn  June-Yi Lee  Andrea Alessandri  Harry H. Hendon 《Climate Dynamics》2015,44(3-4):1073-1091

A significant interdecadal climate shift of interannual variability and predictability of two types of the El Niño-Southern Oscillation (ENSO), namely the canonical or eastern Pacific (EP)-type and Modoki or central Pacific (CP) type, are investigated. Using the retrospective forecasts of six-state-of-the-art coupled models and their multi-model ensemble (MME) for December–January–February during the period of 1972–2005 along with corresponding observed and reanalyzed data, we examine the climate regime shift that occurred in the winter of 1988/1989 and how the shift affected interannual variability and predictability of two types of ENSO for the two periods of 1972–1988 (hereafter PRE) and 1989–2005 (hereafter POST). The result first shows substantial interdecadal changes of observed sea surface temperature (SST) in mean state and variability over the western and central Pacific attributable to the significant warming trend in the POST period. In the POST period, the SST variability increased (decreased) significantly over the western (eastern) Pacific. The MME realistically reproduces the observed interdecadal changes with 1- and 4-month forecast lead time. It is found that the CP-type ENSO was more prominent and predictable during the POST than the PRE period while there was no apparent difference in the variability and predictability of the EP-type ENSO between two periods. Note that the second empirical orthogonal function mode of the Pacific SST during the POST period represents the CP-type ENSO but that during the PRE period captures the ENSO transition phase. The MME better predicts the former than the latter. We also investigate distinctive regional impacts associated with the two types of ENSO during the two periods.  相似文献   

Field application of freezing technology for social infrastructures     

EunChul Shin  YuRa Gong  CheolGyu Jeong 《寒旱区科学》2015,7(5):637-644

There are numerous methods to prevent seepage flow and ground improvement methodologies such as cement grouting, sheet piling, and the membrane method. In this paper, we present case histories of freezing technology applications in the construction of a deep tunnel sewerage system, undersea highway tunnel, and liquefied natural gas tank. Heaving pressure measurements for various soil types around a liquefied natural tank are compared with existing data. In this paper, we present temperature variations at the bottom and side of a liquefied natural gas tank. Our findings show that ground-freezing technology is very effective in controlling ground water infiltration into underground structures as well providing soil reinforcement in the soft ground.  相似文献   

Development of the Operational Oceanographic System of Korea     

Park  Kwang-Soon  Heo  Ki-Young  Jun  Kicheon  Kwon  Jae-Il  Kim  Jinah  Choi  Jin-Yong  Cho  Kyoung-Ho  Choi  Byoung-Ju  Seo  Seung-Nam  Kim  Young Ho  Kim  Sung-Dae  Yang  Chan-Su  Lee  Jong-Chan  Kim  Sang-Ik  Kim  Seonjeong  Choi  Jung-Woon  Jeong  Sang-Hun 《Ocean Science Journal》2015,50(2):353-369

Ocean Science Journal - The Korea Operational Oceanographic System (KOOS) was developed at the Korea Institute of Ocean Science and Technology (KIOST) to produce real-time forecasting and...  相似文献   

First record of three barracudina fishes (Aulopiformes: Teleostei) in Korean waters     

Jin Koo Kim  Jeong -Ho Park  Jung Hwa Choi  Kwang Ho Choi  Yeong Min Choi  Dae Soo Chang  Young Seop Kim 《Ocean Science Journal》2007,42(2):61-67

Three barracudina fishes (Paralepididae) were newly recorded from the southern sea of Korea. Lestidium prolixum is characterized by a single band of luminous ducts on the midventral line and absence of a papilla anterior to the eye. Lestrolepis intermedia and L. japonica are similar in having a black papilla immediately in front of the eye and two bands of luminous ducts on the midventral line. However, the dorsal fin of L. intermedia is located more posterior along the body than that of L. japonica, and L. intermedia have larger number of anal fin rays 42 (vs. 36–40) and vertebrae 95 (vs. 86–87) than L. japonica.  相似文献