180 research outputs found

    Development of a Spatiotemporal Data Model for Management and Visualization of Surface Movement Data

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    Spatiotemporal data is a part of geographical data required in Geographical Information System (GIS). Generally, the existing GIS are not suited to manage changes occurring in the data with time. The capability of managing geographic data with time depends on the underlying data model in which the data model has to take into account the spatiotemporal aspects of the geographic data. Thus, a Spatiotemporal Data Model is required to manage changes in GIS data. Spatiotemporal Data Model represents the abstraction of data management in GIS. Surface movement on three dimensional objects is one of the spatiotemporal data which represents changes of the surface taking place in geographic phenomena. However, current Spatiotemporal Data Model and current GIS software are not adequate for managing the surface movement of three dimensional objects while representing the data. Most of the existing data models brought us to the conclusion that a new Spatiotemporal Data Model is needed to improve the management of three dimensional data with temporal element. Therefore, a new Spatiotemporal Data Model, Surface Movement Spatiotemporal (SMST) Data Model is proposed, which supports the management and visualization of surface movement data in three dimensional objects such as terrain model. The data model were developed under consideration of real world events together with current data collection, for example, a terrain model in the geographic phenomena which deals with changes from time to time based on natural phenomena and human activity. The data were collected by capturing images from time to time. Formalization of the surface movement reconstruction is a fundamental knowledge to develop the SMST Data Model. Currently, in many fields, surface reconstruction does not consider the temporal element. Therefore, the surface movement of three dimensional objects is formalized by enhancing the surface reconstruction method; that is by integrating it with temporal element. In order to test and evaluate the SMST Data Model, a database management system with a loading and a retrieval algorithm suitable to this model were developed. The retrieved data from the database system is saved in the proposed data format for surface movement visualization. In developing the visualization tool, visualization algorithm was used by employing the morphing technique which uses parametric equation. The proposed model was tested using digital terrain model digitized from a series of aerial photos. The model can store and manage surface movement data while reducing the redundancy of data in the database system. Percentage of reduced data redundancy is based on the number of points involved in the movement process. The model stores only the movement points in the surface. Besides, the proposed model can retrieve data for simulating surface movement on the three dimensional object. Therefore, the major contributions of this research are the formalization of surface movement data and the proposed SMST Data Model which can manage surface movement data on three dimensional objects with respect to time

    A review and open issues of multifarious image steganography techniques in spatial domain

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    Nowadays, information hiding is becoming a helpful technique and fetch more attention due fast growth of using internet, it is applied for sending secret information by using different techniques. Steganography is one of major important technique in information hiding. Steganography is science of concealing the secure information within a carrier object to provide the secure communication though the internet, so that no one can recognize and detect itā€™s except the sender & receiver. In steganography, many various carrier formats can be used such as an image, video, protocol, audio. The digital image is most popular used as a carrier file due its frequency on internet. There are many techniques variable for image steganography, each has own strong and weak points. In this study, we conducted a review of image steganography in spatial domain to explore the term image steganography by reviewing, collecting, synthesizing and analyze the challenges of different studies which related to this area published from 2014 to 2017. The aims of this review is provides an overview of image steganography and comparison between approved studies are discussed according to the pixel selection, payload capacity and embedding algorithm to open important research issues in the future works and obtain a robust method

    Rendering process of digital terrain model on mobile devices

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    Digital Terrain Model has been used in many applications especially in Geographical Information System. However with the recent improvement in mobile devices that can support 3 Dimension (3D) content, rendering 3D based terrain on mobile devices is possible. Although mobile devices have improved its capabilities, rendering 3D terrain is tedious due to the constraint in resources of mobile devices. Furthermore, rendering DTM add more constraint and issues to the mobile devices. This paper focuses on the rendering process of DTM on mobile devices to observe some issues and current constraints occurred. Also to determine the characteristic of terrain properties that will affect the rendering performance. Experiments were performed using five datasets that derived from aerial images. The experimental results are based on speed of rendering and the appearance of the terrain surface. From these results, issues and problems that are highlighted in this paper will be the focus of future research

    Performance Evaluation of Attribute and Tuple Timestamping In Temporal Relational Database

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    Modeling temporal database over relational database using 1NF model is considered the most popular approach. This is because of the easy implementation as well as the modeling and querying power of 1NF model. In this paper, we compare a new approach for representing valid-time temporal database (in terms of structure and performance) to the main models in literature with attribute and tuple timestamping. The measurement of the performance is represented by the processing time to get the required temporal data as well as the size of the whole stored temporal data. A test has been performed by running sample queries for the same data in the represented models. Based on the tests, we have found that the new proposed model required less time and used less disk space. Therefore, it is more appropriate for modeling 1NF with interval-based timestamping in relational data model

    A novel zero-watermarking scheme for text document authentication

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    The demand for copyright protection of text documents is extremely vital especially when the text is transmitted over the Internet. One of the best practical resolutions to maintain the security of document media is digital watermarking. Several approaches have been proposed to guarantee the safety and protection of the documents against dishonest copying and distribution. This paper suggests an innovative zero-watermarking scheme for the purpose of authentication and tamper detection in simple text documents. The algorithm generates a watermark based on the effective characters of the text contents which can be extracted later using extraction algorithm to identify the status of tampering in the text document. Experimental results demonstrate the effectiveness of the algorithm against random tampering attacks. Watermark pattern matching and watermark distortion rate are used as evaluation parameters on multiple text samples of varying length

    Formal Specification for Spatial Information Databases Integration Framework (SIDIF)

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    This paper discusses the formal validation for spatial information databases integration framework (SIDIF). A SIDIF database is a large, organized body of persistent data, usually associated with computerized software designed to update, query, and retrieve components of the data stored within the system. One of the common difficulties faced by the developer is in designing a robust database system. Even so, in order to solve this matter, developers have to focus their efforts on the formal specifications. The formal specification is supposed to reduce the overall development time. Formal specifications can be used to provide an unambiguous and precise supplement to natural language descriptions. Besides, it can be rigorously validated and verified leading to the early detection of specification errors. Consequently, to validate this problem formally, we specify the SIDIF database framework using Z language and prove by using Z/EVES theorem proven tool. By using this kind of tools, it may help to reduce time, energy and mistake compared to manual theorem proving which can be error task and tedious

    Characters Segmentation of Cursive Handwritten Words based on Contour Analysis and Neural Network Validation

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    This paper presents a robust algorithm to identify the letter boundaries in images of unconstrained handwritten word . The proposed algorithm is based onĀ  verticalĀ  contourĀ  analysis.Ā  ProposedĀ  algorithmĀ  isĀ  performedĀ  toĀ  generateĀ  presegmentation by analyzing the vertical contours from right to left. The unwanted segmentationĀ  pointsĀ  areĀ  reducedĀ  usingĀ  neuralĀ  networkĀ  validationĀ  toĀ  improve accuracyĀ  ofĀ  segmentation.Ā  TheĀ  neuralĀ  networkĀ  isĀ  utilizedĀ  toĀ  validate segmentationĀ  points.Ā  TheĀ  experimentsĀ  areĀ  performedĀ  onĀ  theĀ  IAMĀ  benchmark database.Ā  TheĀ  resultsĀ  areĀ  showingĀ  thatĀ  theĀ  proposedĀ  algorithmĀ  capableĀ  to accurately locating the letter boundaries for unconstrained handwritten words

    Initial contour generation approach in level set methods for dental image segmentation

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    Segmentation is challenging process in medical images especially on dental x-ray images. Level set methods have effective result on medical and dental image segmentation. Initial Contour (IC) is the essential step in level set image segmentation methods due to start the efficient process. However, the main issue with IC is how to generate the automatic technique in order to reduce the human interaction and moreover, suitable IC to have accurate result. In this paper a new region-based technique for IC generation, is proposed to overcome this issue. The idea is to generate the most suitable IC since the manual initialization of the level set function surface is a well-known drawback for accurate segmentation which has dependency on selection of IC and wrong selection will affect the result. We have utilized the statistical and morphological information inside and outside the contour to establish a region-based map function. This function is able to find the suitable IC on images to perform by level set methods. Experiments on dental x-ray images demonstrate the robustness of segmentation process using proposed method even on noisy images and with weak boundary. Furthermore, computational cost of segmentation process will be reduced

    Statistical Based Audio Forensic on Identical Microphones

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    Microphone forensics has become a challenging field due to the proliferation of recording devices and explosion in video/audio recording. Video or audio recording helps a criminal investigator to analyze the scene and to collect evidences. In this regards, a robust method is required to assure the originality of some recordings. In this paper, we focus on digital audio forensics and study how to identify the microphone model. Defining microphone model will allow the investigators to conclude integrity of some recordings. We perform statistical analysis on the recording that is collected from two microphones of the same model. Experimental results and analysis indicate that the signal of sound recording of identical microphone is not exactly same and the difference is up to 1% - 3%
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