19,757 research outputs found
Identification of SAR Detected Targets on Sea in Near Real Time Applications for Maritime Surveillance
Remote sensing technologies are widely used in maritime surveillance applications. Nowadays, spaceborne Synthetic Aperture Radar (SAR) systems provide outstanding capabilities for target detection at sea for large areas independently from the weather conditions. The generated value added target detection product is composed by complementary information from the Automatic Identification System (AIS). Resulting information layers provides a more reliable picture on the maritime situation awareness. This paper describes the approach of SAR-AIS data fusion and its visualization means developed for Near Real Time (NRT) Applications for Maritime Situational Awareness by the Maritime Security Lab at the Ground Station in Neustrelitz, part DLR’s German Remote Sensing Data Center (DFD). Presented implementation is based on combination of many open source geospatial libraries and frameworks (e.g., GDAL/OGR, Geoserver, PostgresSQL) and shows their effectiveness in the context of complex automated data processing in the frame of NRT requirements
CASTLE4D: AN ARCHAEOLOGICAL INFORMATION SYSTEM BASED ON 3D POINT CLOUDS
[EN] During the past decade, the implementation of 3D visualization and Geographic Information System (GIS) in archaeological research has increased and is now well established. However, the combination of these two factors remains rather complicated when faced with archaeological data. Some of the characteristics of this discipline impose the development of applications that will be able to cope with all of the specificities of archaeological data. Our research aims to create an Archaeological Information System (AIS) that will gather all of the characteristics of an archaeological work. In order to develop such an AIS, our first step was to identify its purposes and consequently, the features that should be available to the users. As it is destined to help with archaeological research, it is therefore of the outmost importance that the particularities of such a study are also taken into account. Moreover, the AIS is intended to incorporate point clouds that serve as a base for the three-dimensional model. These 3D point clouds result from the use of photogrammetry and/or lasergrammetry and, at a later stage, will be inserted into a GIS similar structure. The archaeological data will then be linked to the relevant section of the 3D model. However, these various stages and during the development of the AIS itself, we will encounter a series of issues that require to be addressed in order to produce a working system. This paper aims to identify and define the AIS characteristics as well as the issues and obstacles that we are going to face so that this system becomes a functional tool for archaeological research.Luczfalvy Jancsó, A.; Jonlet, B.; Hallot, P.; Poux, F.; Hoffsummer, P.; Billen, R. (2016). CASTLE4D: AN ARCHAEOLOGICAL INFORMATION SYSTEM BASED ON 3D POINT CLOUDS. En 8th International congress on archaeology, computer graphics, cultural heritage and innovation. Editorial Universitat Politècnica de València. 247-253. https://doi.org/10.4995/arqueologica8.2015.4210OCS24725
Google Earth Visualizations: Preview and Delivery of Hydrographic and Other Marine Datasets
Existing hydrographic data analysis and visualization tools are very powerful, but lack easy access to web data management tools. Virtual globe software provides a gateway to a host of important data products in formats usable by specialized tools such as CARIS, Fledermaus, and Arc/Info. With virtual globe interfaces, users see complimentary and consistent geographic representations of available data in an easy-tonavigate format. We present a preview of visualizations that build upon virtual globe software. These examples are viewed in Google Earth, but could also be implemented in a number of alternative programs (e.g. NASA World Wind, Dapple, OSSIM Planet). We have assembled Google Earth visualizations from three datasets to illustrate each of the four primary types of data (handle point, line, area, and time data). The USCG Marine Information for Safety and Law Enforcement (MISLE) database of ship incidents illustrates point data. A short sample of the USCG National Automatic Identification System logs (N-AIS) demonstrates rendering of line data. Area data is exemplified in the United Nations Convention f the Law of the Sea (UNCLOS) multibeam bathymetry. Point, line and area data are combined to present a preview of S57 chart information. Finally, the MISLE database uses time to show maritime incidents that occurred in US waterways. The visualizations for our initial work were created with hand coding and small scripts. However, tools such as Fledermaus and RockWare have added Google Earth export functionality that makes authoring Google Earth resources easy to construct. For large dataset that require additional processing and analyses, Google Earth visualizations can offer users a range of download formats and suggest what software to use. We believe that this virtual globe-based-approach can make geospatial data sets more widely accessible via the world-wide-web
Penentuan Anomali Aktivitas Kapal Berdasarkan Analisa Data AIS
Upaya memberantas aktivitas ilegal di perairan Indonesia sulit dilakukan dengan hanya mengandalkan patroli laut karena lautan Indonesia sangat luas. Salah satu solusi untuk masalah kemaritiman ini adalah dengan melakukan pemantauan kapal yang beroperasi berdasarkan informasi dari Automatic Identification System (AIS) yang dimiliki oleh setiap kapal yang legal berdasarkan standar internasional. Berdasarkan penelitian yang sudah ada, data yang dikirimkan oleh AIS disimpan ke dalam basis data kemudian ditampilkan visualisasinya kepada pengguna. Diperlukan analisa lebih lanjut dari data yang ada pada basis data beserta visualisasinya untuk membedakan kapal yang beroperasi secara wajar dengan kapal yang terindikasi melakukan pelanggaran.
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The government of Indonesia has been struggling in maintaining its
maritime territory. Meanwhile, it is proven to be difficult for the
government authorities to rely on sea patrol only. One of the attempts to
solve this issue is by supervising every ships which currently doing some
activity in Indonesia’s maritime territory based on the information
provided by Automatic Identification System (AIS). AIS transmitter is
attached to each operating ships based on the regulation of international
law. The existing research shows that data from AIS can be stored and
presented in a virtual map. However, further researches which involve
data analysis from the database and its visualization are necessary in
order to sort out the suspected ships violating the law of Indonesia
territory among the other normal ships
Electronic Chart of the Future: The Hampton Roads Project
ECDIS is evolving from a two-dimensional static display of chart-related data to a decision support system capable of providing real-time or forecast information. While there may not be consensus on how this will occur, it is clear that to do this, ENC data and the shipboard display environment must incorporate both depth and time in an intuitively understandable way. Currently, we have the ability to conduct high-density hydrographic surveys capable of producing ENCs with decimeter contour intervals or depth areas. Yet, our existing systems and specifications do not provide for a full utilization of this capability. Ideally, a mariner should be able to benefit from detailed hydrographic data, coupled with both forecast and real-time water levels, and presented in a variety of perspectives. With this information mariners will be able to plan and carry out transits with the benefit of precisely determined and easily perceived underkeel, overhead, and lateral clearances. This paper describes a Hampton Roads Demonstration Project to investigate the challenges and opportunities of developing the “Electronic Chart of the Future.” In particular, a three-phase demonstration project is being planned: 1. Compile test datasets from existing and new hydrographic surveys using advanced data processing and compilation procedures developed at the University of New Hampshire’s Center for Coastal and Ocean Mapping/Joint Hydrographic Center (CCOM/JHC); 2. Investigate innovative approaches being developed at the CCOM/JHC to produce an interactive time- and tide-aware navigation display, and to evaluate such a display on commercial and/or government vessels; 3. Integrate real-time/forecast water depth information and port information services transmitted via an AIS communications broadcast
A framework to maximise the communicative power of knowledge visualisations
Knowledge visualisation, in the field of information systems, is both a process and a product, informed by the closely aligned fields of information visualisation and knowledg management. Knowledge visualisation has untapped potential within the purview of knowledge communication. Even so, knowledge visualisations are infrequently deployed due to a lack of evidence-based guidance. To improve this situation, we carried out a systematic literature review to derive a number of “lenses” that can be used to reveal the essential perspectives to feed into the visualisation production process.We propose a conceptual framework which incorporates these lenses to guide producers of knowledge visualisations. This framework uses the different lenses to reveal critical perspectives that need to be considered during the design process. We conclude by demonstrating how this framework could be used to produce an effective knowledge visualisation
EMMIX-uskew: An R Package for Fitting Mixtures of Multivariate Skew t-distributions via the EM Algorithm
This paper describes an algorithm for fitting finite mixtures of unrestricted
Multivariate Skew t (FM-uMST) distributions. The package EMMIX-uskew implements
a closed-form expectation-maximization (EM) algorithm for computing the maximum
likelihood (ML) estimates of the parameters for the (unrestricted) FM-MST model
in R. EMMIX-uskew also supports visualization of fitted contours in two and
three dimensions, and random sample generation from a specified FM-uMST
distribution.
Finite mixtures of skew t-distributions have proven to be useful in modelling
heterogeneous data with asymmetric and heavy tail behaviour, for example,
datasets from flow cytometry. In recent years, various versions of mixtures
with multivariate skew t (MST) distributions have been proposed. However, these
models adopted some restricted characterizations of the component MST
distributions so that the E-step of the EM algorithm can be evaluated in closed
form. This paper focuses on mixtures with unrestricted MST components, and
describes an iterative algorithm for the computation of the ML estimates of its
model parameters.
The usefulness of the proposed algorithm is demonstrated in three
applications to real data sets. The first example illustrates the use of the
main function fmmst in the package by fitting a MST distribution to a bivariate
unimodal flow cytometric sample. The second example fits a mixture of MST
distributions to the Australian Institute of Sport (AIS) data, and demonstrate
that EMMIX-uskew can provide better clustering results than mixtures with
restricted MST components. In the third example, EMMIX-uskew is applied to
classify cells in a trivariate flow cytometric dataset. Comparisons with other
available methods suggests that the EMMIX-uskew result achieved a lower
misclassification rate with respect to the labels given by benchmark gating
analysis
The dominant of Bloggers in Malaysian politics through social networks
Every country in this world has own political issues. In Malaysia for example, political issues played an important role that can influence other factors such as social and economy. As we all know, political factor can give positive and negative effect to a situation in Malaysia. The frequent usage of computer nowadays by Malaysian people helps in spreading information and news about political situation in Malaysia through cyberspace. In this paper, we use web mining system with Artificial Immune System (AIS) to regain a small group of relevant websites and webpages on political issues in Malaysia. To analyze the relationship between website and webpages, the concept of social networks will be used. Result from the web mining system with AIS will be used to understand the impact of social network to the political situation in Malaysia
A web based solution to track trawl vessel activities over pipelines in Norwegian Continental Shelf
Vessel activities such as trawling and anchoring potentially affect pipeline integrity. Therefore, the detailed information about the trawl activity in the area is essential for accurate assessment of pipeline, where to inspect and where to implement corrective intervention, based on up to date trawling intensity and equipment used. The main contribution of this paper is to present a detailed analysis of trawling vessels activities based on the automatic identification system (AIS) data combined with DNV GL ship register, data from HIS Maritime World Register of Ships and information gathered on the trawl equipment. In this aspect, an interactive web-based solution has been designed and developed to monitor and track trawl vessel activities in the Norwegian Continental Shelf which can be used for assessing integrity of pipelines. Data Analysis and visualization techniques have been utilized to transfer high-dimensional data by encoding it as visual objects contained in graphical presentations. The extracted knowledge result in the density mapping, vessel tracking, computing crossing points of trawl vessel paths, computing a buffered polygon around the pipeline for the chosen threshold and cross-over statistics of pipeline and vessels, etc. The use of such a framework is mostly advantageous for the port authorities, marine transportation, relevant fisheries management authority, etc.publishedVersio
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