People's diversified tourism needs provide a broad development space and atmosphere for various tourism forms. The geographic resource information of the tourism unit can vividly highlight the unit's geographic spatial location and reflect the individual's spatial and attribute characteristics. It is not only the main goal of researching the information base of tourism resources, but it is also the difficulty that needs to be solved at present. This paper describes the use of image processing technology to realize the analysis and positioning of geographic tourism resources. Specifically, we propose a conditional generative adversarial network (CGAN) model, Ra-CGAN, with a multi-level channel attention mechanism. First, we built a generative model G with a multi-level channel attention mechanism. By fusing deep semantic and shallow detail information containing the attention mechanism, the network can extract rich contextual information. Second, we constructed a discriminative network D. We improved the segmentation results by correcting the difference between the ground-truth label map and the segmentation map generated by the generative model. Finally, through adversarial training between G and D with conditional constraints, we enabled high-order data distribution features learning to improve the boundary accuracy and smoothness of the segmentation results. In this study, the proposed method was validated on the large-scale remote sensing image object detection datasets DIOR and DOTA. Compared with the existing work, the method proposed in this paper achieves very good performance.
{"title":"Analysis and positioning of geographic tourism resources based on image processing method with Ra-CGAN modeling","authors":"Xiuxia Li","doi":"10.3934/geosci.2022036","DOIUrl":"https://doi.org/10.3934/geosci.2022036","url":null,"abstract":"People's diversified tourism needs provide a broad development space and atmosphere for various tourism forms. The geographic resource information of the tourism unit can vividly highlight the unit's geographic spatial location and reflect the individual's spatial and attribute characteristics. It is not only the main goal of researching the information base of tourism resources, but it is also the difficulty that needs to be solved at present. This paper describes the use of image processing technology to realize the analysis and positioning of geographic tourism resources. Specifically, we propose a conditional generative adversarial network (CGAN) model, Ra-CGAN, with a multi-level channel attention mechanism. First, we built a generative model G with a multi-level channel attention mechanism. By fusing deep semantic and shallow detail information containing the attention mechanism, the network can extract rich contextual information. Second, we constructed a discriminative network D. We improved the segmentation results by correcting the difference between the ground-truth label map and the segmentation map generated by the generative model. Finally, through adversarial training between G and D with conditional constraints, we enabled high-order data distribution features learning to improve the boundary accuracy and smoothness of the segmentation results. In this study, the proposed method was validated on the large-scale remote sensing image object detection datasets DIOR and DOTA. Compared with the existing work, the method proposed in this paper achieves very good performance.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70249670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we introduce a novel inversion methodology that combines the benefits offered by Reinforcement-Learning techniques with the advantages of the Epsilon-Greedy method for an expanded exploration of the model space. Among the various Reinforcement Learning approaches, we applied the set of algorithms included in the category of the Q-Learning methods. We show that the Temporal Difference algorithm offers an effective iterative approach that allows finding an optimal solution in geophysical inverse problems. Furthermore, the Epsilon-Greedy method properly coupled with the Reinforcement Learning workflow, allows expanding the exploration of the model-space, minimizing the misfit between observed and predicted responses and limiting the problem of local minima of the cost function. In order to prove the feasibility of our methodology, we tested it using synthetic geo-electric data and a seismic refraction data set available in the public domain.
{"title":"Reinforcement learning in optimization problems. Applications to geophysical data inversion","authors":"P. Dell’Aversana","doi":"10.3934/geosci.2022027","DOIUrl":"https://doi.org/10.3934/geosci.2022027","url":null,"abstract":"In this paper, we introduce a novel inversion methodology that combines the benefits offered by Reinforcement-Learning techniques with the advantages of the Epsilon-Greedy method for an expanded exploration of the model space. Among the various Reinforcement Learning approaches, we applied the set of algorithms included in the category of the Q-Learning methods. We show that the Temporal Difference algorithm offers an effective iterative approach that allows finding an optimal solution in geophysical inverse problems. Furthermore, the Epsilon-Greedy method properly coupled with the Reinforcement Learning workflow, allows expanding the exploration of the model-space, minimizing the misfit between observed and predicted responses and limiting the problem of local minima of the cost function. In order to prove the feasibility of our methodology, we tested it using synthetic geo-electric data and a seismic refraction data set available in the public domain.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70249836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conventional geothermal energy systems are limited by hydrogeological conditions and environmental risks, and wind/solar solutions have issues with intermittency and the need for grid storage. Deep closed-loop geothermal systems such as the Eavor-Loop are championed as scalable, dispatchable, zero-emission alternative energy technologies, but as yet they are largely untested. A series of numerical models are created using the finite element method to evaluate the power output claims made by Eavor. The models use typical parameter values to create a simplified study domain. The modelling results show that the power output claims are plausible, although the upper range of their predictions would likely require production temperatures in excess of 150 ℃. The technology is shown to be scalable by adding additional lateral wellbore arrays, but this leads to a reduction in efficiency due to thermal interference. It is demonstrated that the presence of groundwater can improve power output at relatively high hydraulic conductivity values. Doubt is cast on the likelihood of finding such values in the deep subsurface. Flow rate is shown to increase power output, but the practicality of using it to follow energy demand is not established. Various limitations of the study are discussed, and suggestions are made for future work which could fill in the remaining knowledge gaps.
{"title":"Numerical modelling of a deep closed-loop geothermal system: evaluating the Eavor-Loop","authors":"Joseph J. Kelly, C. McDermott","doi":"10.3934/geosci.2022011","DOIUrl":"https://doi.org/10.3934/geosci.2022011","url":null,"abstract":"Conventional geothermal energy systems are limited by hydrogeological conditions and environmental risks, and wind/solar solutions have issues with intermittency and the need for grid storage. Deep closed-loop geothermal systems such as the Eavor-Loop are championed as scalable, dispatchable, zero-emission alternative energy technologies, but as yet they are largely untested. A series of numerical models are created using the finite element method to evaluate the power output claims made by Eavor. The models use typical parameter values to create a simplified study domain. The modelling results show that the power output claims are plausible, although the upper range of their predictions would likely require production temperatures in excess of 150 ℃. The technology is shown to be scalable by adding additional lateral wellbore arrays, but this leads to a reduction in efficiency due to thermal interference. It is demonstrated that the presence of groundwater can improve power output at relatively high hydraulic conductivity values. Doubt is cast on the likelihood of finding such values in the deep subsurface. Flow rate is shown to increase power output, but the practicality of using it to follow energy demand is not established. Various limitations of the study are discussed, and suggestions are made for future work which could fill in the remaining knowledge gaps.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70249862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper aims at investigating images of places as a narrative element. In particular, dichotomous reference will be made to the global images of places that arise from dominant narratives versus the cultural images of places that arise from sensorial and experienced life. Starting from theoretical reflection on the role of images and narratives with respect to the perception, imagery and experience of places, this contribution will focus on the sense of place and the influence of direct experience on its formation. The work deepens critical issues and capabilities of the digital visual methodology combined with sensory ethnography. The research, from an empirical point of view, was carried out as a teaching laboratory during the Geography for Tourism Science course at the University of Insubria. The students were invited to direct observation of their own place of life, with the aim of analysing its cultural image, and also to mediated observation of a known place not known directly but known through famous images and representations, with the aim of analysing its global image. This exercise outdoor allowed students to compare the theoretical concepts learned in the classroom with their perceptions of their everyday geographies, transferring the study of theory to everyday life as a tool to better understand their own and daily experience.
{"title":"Global images vs cultural images: mixed methods to deepen territorial representations","authors":"V. Albanese","doi":"10.3934/geosci.2022032","DOIUrl":"https://doi.org/10.3934/geosci.2022032","url":null,"abstract":"This paper aims at investigating images of places as a narrative element. In particular, dichotomous reference will be made to the global images of places that arise from dominant narratives versus the cultural images of places that arise from sensorial and experienced life. Starting from theoretical reflection on the role of images and narratives with respect to the perception, imagery and experience of places, this contribution will focus on the sense of place and the influence of direct experience on its formation. The work deepens critical issues and capabilities of the digital visual methodology combined with sensory ethnography. The research, from an empirical point of view, was carried out as a teaching laboratory during the Geography for Tourism Science course at the University of Insubria. The students were invited to direct observation of their own place of life, with the aim of analysing its cultural image, and also to mediated observation of a known place not known directly but known through famous images and representations, with the aim of analysing its global image. This exercise outdoor allowed students to compare the theoretical concepts learned in the classroom with their perceptions of their everyday geographies, transferring the study of theory to everyday life as a tool to better understand their own and daily experience.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70249971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper examines the transboundary water resources conflict resolution mechanisms. Although different research perspectives, including social planner, water market, game theory, static and dynamic systems engineering model, have already provided conflict resolution mechanisms that could be used to analyze transboundary water conflicts, here an ecosystemic approach based on an analytical model, is proposed. For this aim the case of GERD "Grand Ethiopian Renaissance Dam" on Nile Azzurro, is analyzed. The scenario of the GERD dam, besides being current and interesting in the water dispute between Egypt, Sudan and Ethiopia, is suitable for the application of the proposed analytical model. This model could permit researchers and practitioners to develop more comprehensive mechanisms, complementary to political strategies, with stronger analytical capacity to analyze the different elements of the process of transboundary water dispute resolution.
{"title":"The GERD dam in the water dispute between Ethiopia, Sudan and Egypt. A scenario analysis in an ecosystem approach between physical and geopolitical geography","authors":"S. de Falco, Giulia Fiorentino","doi":"10.3934/geosci.2022014","DOIUrl":"https://doi.org/10.3934/geosci.2022014","url":null,"abstract":"This paper examines the transboundary water resources conflict resolution mechanisms. Although different research perspectives, including social planner, water market, game theory, static and dynamic systems engineering model, have already provided conflict resolution mechanisms that could be used to analyze transboundary water conflicts, here an ecosystemic approach based on an analytical model, is proposed. For this aim the case of GERD \"Grand Ethiopian Renaissance Dam\" on Nile Azzurro, is analyzed. The scenario of the GERD dam, besides being current and interesting in the water dispute between Egypt, Sudan and Ethiopia, is suitable for the application of the proposed analytical model. This model could permit researchers and practitioners to develop more comprehensive mechanisms, complementary to political strategies, with stronger analytical capacity to analyze the different elements of the process of transboundary water dispute resolution.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70249997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper will describe the creation of an interactive and flexible map through which news and information relating to the tangible and intangible cultural and natural heritage of the Sila National Park area (Calabria, southern Italy, related to the Italian Risorgimento period) were collected. The map, which can be updated daily, can be accessed by clicking on a location's reference. The pop-up window contains information for each character, monument, commemorative plaque and palace linked to the history of the Risorgimento. Anthropological and oral traditions linked to the affected area are also listed. The map is enriched by a focus on significant archaeological presences, characters and productive activities linked to the Risorgimento or our present time. Each pop-up is also characterized by the possibility of viewing any photographs and historical documentation, as well as research videos and educational and informative material. This paper's research questions concern 1) how the thematic map on Google Maps can be useful for educational purposes and 2) how the map was used to enhance the cultural and natural heritage of the Sila National Park and to promote an ethics-based tourism during and after the pandemic. The historical-geographical itinerary of the map, therefore, offers hints and suggestions for sustainable cultural tourism initiatives open to international context and proximity. Neogeographic technologies such as Google Maps have been used because they facilitate and stimulate the sharing and production of geographic information. In the case of this map, it was created from a bottom-up approach that involved local stakeholders and scholars.
{"title":"Educational thematic mapping of cultural & natural heritage in southern Italy during and after the COVID-19 pandemic","authors":"F. De Pascale, G. Ferraro","doi":"10.3934/geosci.2022037","DOIUrl":"https://doi.org/10.3934/geosci.2022037","url":null,"abstract":"This paper will describe the creation of an interactive and flexible map through which news and information relating to the tangible and intangible cultural and natural heritage of the Sila National Park area (Calabria, southern Italy, related to the Italian Risorgimento period) were collected. The map, which can be updated daily, can be accessed by clicking on a location's reference. The pop-up window contains information for each character, monument, commemorative plaque and palace linked to the history of the Risorgimento. Anthropological and oral traditions linked to the affected area are also listed. The map is enriched by a focus on significant archaeological presences, characters and productive activities linked to the Risorgimento or our present time. Each pop-up is also characterized by the possibility of viewing any photographs and historical documentation, as well as research videos and educational and informative material. This paper's research questions concern 1) how the thematic map on Google Maps can be useful for educational purposes and 2) how the map was used to enhance the cultural and natural heritage of the Sila National Park and to promote an ethics-based tourism during and after the pandemic. The historical-geographical itinerary of the map, therefore, offers hints and suggestions for sustainable cultural tourism initiatives open to international context and proximity. Neogeographic technologies such as Google Maps have been used because they facilitate and stimulate the sharing and production of geographic information. In the case of this map, it was created from a bottom-up approach that involved local stakeholders and scholars.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70249684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The relationship between Geography and the Visual has always been strong intertwined. As it is true that Geography has always operates through images (in the form of pictures, creative representations and above all cartographies), in the last two years, with the distance learning due to the spread of the Covid-19 pandemic, this phenomenon has not only increased, but it also became necessary. "The classroom as the most radical space", in the words of bell hooks, had to turn into a virtual space, where images have a fundamental role in the teaching/learning process. This paper wants to analyse the relationship between Geography and the Visual by analysing three images we used in the lessons of the course Geopolitics of Migration at the University of Palermo during the academic year 2020–2021, that speak about the "Mediterranean Complex". With this expression, inspired by Mirzoeff's work, I will briefly focus on the clash between dominant visuality and the counter-visualities emerging from the Mediterranean Sea, a particular sea-space where on the one hand, violent geopolitics daily act against migrants' crossing; on the other hand, new imaginative geographies emerge against coloniality devices of power and knowledge. A further reflection will be dedicated to the use of these images as a didactic tool. Why do we use these images? What do they tell us? Which one is the relationship between our increasingly digital classrooms and these images? If it is true that the pandemic phenomenon is acting as a laboratory of experimentation and acceleration, how is the visual nature of geography changing and participating to the construction of our knowledge? This contribution is a first attempt to reflect about those questions through the visuality and the counter-visualities of the "Mediterranean complex".
{"title":"Visual Methodologies and Geography's education in the pandemic time: notes on geopolitics of migration in the \"Mediterranean Complex\"","authors":"Gabriella Palermo","doi":"10.3934/geosci.2022015","DOIUrl":"https://doi.org/10.3934/geosci.2022015","url":null,"abstract":"The relationship between Geography and the Visual has always been strong intertwined. As it is true that Geography has always operates through images (in the form of pictures, creative representations and above all cartographies), in the last two years, with the distance learning due to the spread of the Covid-19 pandemic, this phenomenon has not only increased, but it also became necessary. \"The classroom as the most radical space\", in the words of bell hooks, had to turn into a virtual space, where images have a fundamental role in the teaching/learning process. This paper wants to analyse the relationship between Geography and the Visual by analysing three images we used in the lessons of the course Geopolitics of Migration at the University of Palermo during the academic year 2020–2021, that speak about the \"Mediterranean Complex\". With this expression, inspired by Mirzoeff's work, I will briefly focus on the clash between dominant visuality and the counter-visualities emerging from the Mediterranean Sea, a particular sea-space where on the one hand, violent geopolitics daily act against migrants' crossing; on the other hand, new imaginative geographies emerge against coloniality devices of power and knowledge. A further reflection will be dedicated to the use of these images as a didactic tool. Why do we use these images? What do they tell us? Which one is the relationship between our increasingly digital classrooms and these images? If it is true that the pandemic phenomenon is acting as a laboratory of experimentation and acceleration, how is the visual nature of geography changing and participating to the construction of our knowledge? This contribution is a first attempt to reflect about those questions through the visuality and the counter-visualities of the \"Mediterranean complex\".","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70250010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study examines how the atmospheric circulation patterns in Africa south of the equator govern the spatial distribution of precipitation in Zimbabwe. The moisture circulation patterns are designated by an ample set of eight classified circulation types (CTs). Here it is shown that all wet CTs over Zimbabwe features enhanced cyclonic/convective activity in the southwest Indian Ocean. Therefore, enhanced moisture availability in the southwest Indian Ocean is necessary for rainfall formation in parts of Zimbabwe. The wettest CT in Zimbabwe is characterized by a ridging South Atlantic Ocean high-pressure, south of South Africa, driving an abundance of southeast moisture fluxes, from the southwest Indian Ocean into Zimbabwe. Due to the proximity of Zimbabwe to the Agulhas and Mozambique warm current, the activity of the ridging South Atlantic Ocean anticyclone is a dominant synoptic feature that favors above-average rainfall in Zimbabwe. Also, coupled with a weaker state of the Mascarene high, it is shown that a ridging South Atlantic Ocean high-pressure, south of South Africa, can be favorable for the southwest movement of tropical cyclones into the eastern coastal landmasses resulting in above-average rainfall in Zimbabwe. The driest CT is characterized by the northward track of the Southern Hemisphere mid-latitude cyclones leading to enhanced westerly fluxes in the southwest Indian Ocean, limiting moist southeast winds into Zimbabwe.
{"title":"Relationship between synoptic circulations and the spatial distributions of rainfall in Zimbabwe","authors":"C. Ibebuchi, Itohan-Osa Abu","doi":"10.3934/geosci.2023001","DOIUrl":"https://doi.org/10.3934/geosci.2023001","url":null,"abstract":"This study examines how the atmospheric circulation patterns in Africa south of the equator govern the spatial distribution of precipitation in Zimbabwe. The moisture circulation patterns are designated by an ample set of eight classified circulation types (CTs). Here it is shown that all wet CTs over Zimbabwe features enhanced cyclonic/convective activity in the southwest Indian Ocean. Therefore, enhanced moisture availability in the southwest Indian Ocean is necessary for rainfall formation in parts of Zimbabwe. The wettest CT in Zimbabwe is characterized by a ridging South Atlantic Ocean high-pressure, south of South Africa, driving an abundance of southeast moisture fluxes, from the southwest Indian Ocean into Zimbabwe. Due to the proximity of Zimbabwe to the Agulhas and Mozambique warm current, the activity of the ridging South Atlantic Ocean anticyclone is a dominant synoptic feature that favors above-average rainfall in Zimbabwe. Also, coupled with a weaker state of the Mascarene high, it is shown that a ridging South Atlantic Ocean high-pressure, south of South Africa, can be favorable for the southwest movement of tropical cyclones into the eastern coastal landmasses resulting in above-average rainfall in Zimbabwe. The driest CT is characterized by the northward track of the Southern Hemisphere mid-latitude cyclones leading to enhanced westerly fluxes in the southwest Indian Ocean, limiting moist southeast winds into Zimbabwe.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70250201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Siri Lakshatha, D. Venkata Ratnam, K. Sivakrishna
The major source of error in the positioning of GNSS is from the region of Ionosphere. The single-frequency GNSS receiver cannot eliminate the ionospheric error due to dispersive medium and frequency-dependent. The low-cost GNSS receivers are highly dependent on single-frequency approaches of Ionosphere region popularly known as Klobuchar, NeQuick G, and BDS2 methods to estimate the data of position, velocity and time. The regional satellite navigation system of India, known as Navigation with Indian Constellation (NavIC) adopted ionospheric models based on single-frequency namely, Klobuchar and grid-based correction models. The Klobuchar modelos accuracy is less for predicting ionospheric delays in low latitude regions like India under Equatorial Ionization Anomaly (EIA) conditions. In this paper, the NeQuick G modelos applicability for NavIC users over the Indian region is investigated. NeQuick G modelos performance is validated with dense GPS TEC network data of 26 stations spread across India and IRI-2016 model, during 2014, 2015 and 2016. The predicted TEC results indicate that EIA structures are well captured by NeQuick G and IRI-2016 models. The results indicate that both NeQuick G and IRI-2016 models well predict season asymmetry and decrease of TEC intensity due to descending phase solar cycle activity. It is found that NeQuick G is one of the contenders of single frequency ionospheric models for GNSS/NavIC users in India.
GNSS定位误差的主要来源是电离层区域。单频GNSS接收机由于介质色散和频率依赖，无法消除电离层误差。低成本GNSS接收机高度依赖电离层区域的单频方法，即Klobuchar、NeQuick G和BDS2方法来估计位置、速度和时间数据。印度区域卫星导航系统NavIC采用了基于单频即Klobuchar的电离层模型和基于网格的校正模型。在赤道电离异常(EIA)条件下，Klobuchar模型对印度等低纬度地区电离层延迟的预测精度较低。本文研究了NeQuick G模型在印度地区NavIC用户中的适用性。NeQuick G modelos的性能在2014年、2015年和2016年用分布在印度的26个站点的密集GPS TEC网络数据和ir -2016模型进行了验证。预测的TEC结果表明，NeQuick G和IRI-2016模型可以很好地捕获EIA结构。结果表明，NeQuick G和IRI-2016模型均能较好地预测季节不对称性和由于太阳周期活动下降引起的TEC强度下降。发现NeQuick G是印度GNSS/NavIC用户单频电离层模型的竞争者之一。
{"title":"Applicability of NeQuick G ionospheric model for single-frequency GNSS users over India","authors":"K. Siri Lakshatha, D. Venkata Ratnam, K. Sivakrishna","doi":"10.3934/geosci.2022008","DOIUrl":"https://doi.org/10.3934/geosci.2022008","url":null,"abstract":"The major source of error in the positioning of GNSS is from the region of Ionosphere. The single-frequency GNSS receiver cannot eliminate the ionospheric error due to dispersive medium and frequency-dependent. The low-cost GNSS receivers are highly dependent on single-frequency approaches of Ionosphere region popularly known as Klobuchar, NeQuick G, and BDS2 methods to estimate the data of position, velocity and time. The regional satellite navigation system of India, known as Navigation with Indian Constellation (NavIC) adopted ionospheric models based on single-frequency namely, Klobuchar and grid-based correction models. The Klobuchar modelos accuracy is less for predicting ionospheric delays in low latitude regions like India under Equatorial Ionization Anomaly (EIA) conditions. In this paper, the NeQuick G modelos applicability for NavIC users over the Indian region is investigated. NeQuick G modelos performance is validated with dense GPS TEC network data of 26 stations spread across India and IRI-2016 model, during 2014, 2015 and 2016. The predicted TEC results indicate that EIA structures are well captured by NeQuick G and IRI-2016 models. The results indicate that both NeQuick G and IRI-2016 models well predict season asymmetry and decrease of TEC intensity due to descending phase solar cycle activity. It is found that NeQuick G is one of the contenders of single frequency ionospheric models for GNSS/NavIC users in India.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70249802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper aims at scrutinizing the role of two overlapping dimensions in tourism geography teaching and learning: the real-world perspective, represented by the fieldwork as a long-established practice in geographical teaching; and the digital sphere, namely the use of visual methodologies and social media as tools to activate city image-making in tourist practices. In particular, the work deepens critical aspects and potentialities of a mixed-method approach combining both traditional methods and more innovative tools to carry out researches and teaching in the field of tourism geography and cultural heritage. Theoretically inserted at the interplay among tourism, digital geography and visual methods, it draws on a series of workshops organized with third-level students between 2016 and 2018. Although problematizing some crucial conceptual issues related to the role of visualities and new technologies, findings highlight the didactic effectiveness of mixed methods that entail the more traditional ones such as team working and fieldworks, and the most innovative such as visual methods and social media, to increase students' interest in geography learning and stimulating their own perceptions of ordinary landscapes through a gaze repositioning.
{"title":"The insiders' gaze: fieldworks, social media and visual methodologies in urban tourism","authors":"T. Graziano","doi":"10.3934/geosci.2022021","DOIUrl":"https://doi.org/10.3934/geosci.2022021","url":null,"abstract":"This paper aims at scrutinizing the role of two overlapping dimensions in tourism geography teaching and learning: the real-world perspective, represented by the fieldwork as a long-established practice in geographical teaching; and the digital sphere, namely the use of visual methodologies and social media as tools to activate city image-making in tourist practices. In particular, the work deepens critical aspects and potentialities of a mixed-method approach combining both traditional methods and more innovative tools to carry out researches and teaching in the field of tourism geography and cultural heritage. Theoretically inserted at the interplay among tourism, digital geography and visual methods, it draws on a series of workshops organized with third-level students between 2016 and 2018. Although problematizing some crucial conceptual issues related to the role of visualities and new technologies, findings highlight the didactic effectiveness of mixed methods that entail the more traditional ones such as team working and fieldworks, and the most innovative such as visual methods and social media, to increase students' interest in geography learning and stimulating their own perceptions of ordinary landscapes through a gaze repositioning.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70249725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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