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Search Results: 1 - 10 of 33 matches for " Charith Abhayaratne "
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2D+t Wavelet Domain Video Watermarking
Deepayan Bhowmik,Charith Abhayaratne
Advances in Multimedia , 2012, DOI: 10.1155/2012/973418
Abstract: A novel watermarking framework for scalable coded video that improves the robustness against quality scalable compression is presented in this paper. Unlike the conventional spatial-domain (t?+?2D) water-marking scheme where the motion compensated temporal filtering (MCTF) is performed on the spatial frame-wise video data to decompose the video, the proposed framework applies the MCTF in the wavelet domain (2D?+?t) to generate the coefficients to embed the watermark. Robustness performances against scalable content adaptation, such as Motion JPEG 2000, MC-EZBC, or H.264-SVC, are reviewed for various combinations of motion compensated 2D?+?t?+?2D using the proposed framework. The MCTF is improved by modifying the update step to follow the motion trajectory in the hierarchical temporal decomposition by using direct motion vector fields in the update step and implied motion vectors in the prediction step. The results show smaller embedding distortion in terms of both peak signal to noise ratio and flickering metrics compared to frame-by-frame video watermarking while the robustness against scalable compression is improved by using 2D?+?t over the conventional t?+?2D domain video watermarking, particularly for blind watermarking schemes where the motion is estimated from the watermarked video. 1. Introduction Several attempts have been made to extend the image watermarking algorithms into video watermarking by using them either on frame-by-frame basis or on 3D decomposed video. The initial attempts on video watermarking were made by frame-by-frame embedding [1–4], due to its simplicity in implementation using image watermarking algorithms. Such watermarking algorithms consider embedding on selected frames located at fixed intervals to make them robust against frame dropping-based temporal adaptations of video. In this case, each frame is treated separately as an individual image; hence, any image-watermarking algorithm can be adopted to achieve the intended robustness. But frame-by-frame watermarking schemes often perform poorly in terms of flickering artefacts and robustness against various video processing attacks including temporal desynchronization, video collusion, video compression attacks, and so forth. In order to address some of these issues, the video temporal dimension is exploited using different transforms, such as discrete Fourier transform (DFT), discrete cosine transform (DCT), or discrete wavelet transform (DWT). These algorithms decompose the video by performing spatial 2D transform on individual frames followed by 1D transform in the
Improve the Sustainability of Internet of Things Through Trading-based Value Creation
Charith Perera,Arkady Zaslavsky
Computer Science , 2014,
Abstract: Internet of Things (IoT) has been widely discussed over the past few years in technology point of view. However, the social aspects of IoT are seldom studied to date. In this paper, we discuss the IoT in social point of view. Specifically, we examine the strategies to increase the adoption of IoT in a sustainable manner. Such discussion is essential in today's context where adoption of IoT solutions by non-technical community is slow. Specially, large number of IoT solutions making their way into the market every day. We propose an trading-based value creation model based on sensing as a service paradigm in order to fuel the adoption of IoT. We discuss the value creation and its impact towards the society especially to households and their occupants. We also present results of two different surveys we conducted in order to examine the potential acceptance of the proposed model among the general public.
Temperature Effects on Gas Sensing Properties of Electrodeposited Chlorine Doped and Undoped n-Type Cuprous Oxide Thin Films  [PDF]
Nayana Bandara, Charith Jayathilaka, Dhammika Dissanayaka, Sumedha Jayanetti
Journal of Sensor Technology (JST) , 2014, DOI: 10.4236/jst.2014.43011
Abstract:
As one of the most widely used domestic fuels, the detection of possible leakages of Liquefied Petroleum (LP) gas from production plants, from cylinders during their storage, transport and usage is of utmost importance. This article discusses a study of the response of undoped and chlorine doped electrodeposited n-type Cuprous Oxide (Cu2O) films to of LP gas. Undoped n-type Cu2O films were fabricated in an electrolyte bath containing a solution of sodium acetate and cupric acetate whereas n-type chlorine doped Cu2O thin films were prepared by adding a 0.02 M cuprous chloride (CuCl2) into an electrolyte solution containing lactic acid, cupric sulfate and sodium hydroxide. The n-type conductivity of the deposited films was determined using spectral response measurements. The structural and morphological properties of the fabricated films were monitored using X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Due to doping, the overall conductivity of the chlorine doped n-type Cu2O films increased by several orders of magnitude. The temperature dependent gas responses of both the undoped and chlorine doped n-type Cu2O thin films to the LP gas was monitored by measuring the electrical resistance (R), and using the contact probe method at a constant gas flow rate of 0.005 ml/s. Upon exposure to gases, both doped and undoped films showed a good response to the gas by increasing/decreasing the electrical resistance by ΔR. The undoped n-type Cu2O thin films showed a negative response (ΔR < 0) at all temperatures resulting in a maximum response around 85°C. However, the chlorine doped n-type Cu2O thin films initially showed a positive response (ΔR > 0) to the LP gas which then reversed its sign to give a negative response which peaked at 52°C. The positive response shown by the chlorine doped Cu2O films vanished completely at 42°C.
A tomographic study of V691 CrA (X1822-371)
Charith Peris,Saeqa Dil Vrtilek
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.22039.x
Abstract: We present Doppler and modulation tomography of the low-mass X-ray binary V691 CrA with data obtained using the 6.5-m Magellan Baade telescope at the Las Campanas Observatory in 2010 and 2011. The disc and hotspot are observed in H\alpha and He II (\lambda 4686) in both years. A clear image of the disc is seen in He II (\lambda 5411) using the 2010 data. We present the first tomography of the absorption line He I (\lambda 5876) and detect absorption near the L_1 point of the donor star. We also present the first modulation tomography of the emission line H\alpha and detect emission from the secondary. The H\alpha double peaks are imbedded in a deep absorption trough confirming the presence of Balmer line absorbing material in the system. Our observations of H\alpha show absorption in a larger phase range than in H\beta which could be due to heating up of sprayed matter from the hotspot as it travels downstream. We also suggest possible occultation of the H\alpha absorbing spray by the disc bulge at certain phases.
Sensing as a Service and Big Data
Arkady Zaslavsky,Charith Perera,Dimitrios Georgakopoulos
Computer Science , 2013,
Abstract: Internet of Things (IoT) will comprise billions of devices that can sense, communicate, compute and potentially actuate. Data streams coming from these devices will challenge the traditional approaches to data management and contribute to the emerging paradigm of big data. This paper discusses emerging Internet of Things (IoT) architecture, large scale sensor network applications, federating sensor networks, sensor data and related context capturing techniques, challenges in cloud-based management, storing, archiving and processing of sensor data.
Natural Notation for the Domestic Internet of Things
Charith Perera,Saeed Aghaee,Alan Blackwell
Computer Science , 2015,
Abstract: This study explores the use of natural language to give instructions that might be interpreted by Internet of Things (IoT) devices in a domestic `smart home' environment. We start from the proposition that reminders can be considered as a type of end-user programming, in which the executed actions might be performed either by an automated agent or by the author of the reminder. We conducted an experiment in which people wrote sticky notes specifying future actions in their home. In different conditions, these notes were addressed to themselves, to others, or to a computer agent.We analyse the linguistic features and strategies that are used to achieve these tasks, including the use of graphical resources as an informal visual language. The findings provide a basis for design guidance related to end-user development for the Internet of Things.
The Emerging Internet of Things Marketplace From an Industrial Perspective: A Survey
Charith Perera,Chi Harold Liu,Srimal Jayawardena
Computer Science , 2015,
Abstract: The Internet of Things (IoT) is a dynamic global information network consisting of internet-connected objects, such as Radio-frequency identification (RFIDs), sensors, actuators, as well as other instruments and smart appliances that are becoming an integral component of the future internet. Over the last decade, we have seen a large number of the IoT solutions developed by start-ups, small and medium enterprises, large corporations, academic research institutes (such as universities), and private and public research organisations making their way into the market. In this paper, we survey over one hundred IoT smart solutions in the marketplace and examine them closely in order to identify the technologies used, functionalities, and applications. More importantly, we identify the trends, opportunities and open challenges in the industry-based the IoT solutions. Based on the application domain, we classify and discuss these solutions under five different categories: smart wearable, smart home, smart, city, smart environment, and smart enterprise. This survey is intended to serve as a guideline and conceptual framework for future research in the IoT and to motivate and inspire further developments. It also provides a systematic exploration of existing research and suggests a number of potentially significant research directions.
End-to-End Privacy for Open Big Data Markets
Charith Perera,Rajiv Ranjan,Lizhe Wang
Computer Science , 2015,
Abstract: The idea of an open data market envisions the creation of a data trading model to facilitate exchange of data between different parties in the Internet of Things (IoT) domain. The data collected by IoT products and solutions are expected to be traded in these markets. Data owners will collect data using IoT products and solutions. Data consumers who are interested will negotiate with the data owners to get access to such data. Data captured by IoT products will allow data consumers to further understand the preferences and behaviours of data owners and to generate additional business value using different techniques ranging from waste reduction to personalized service offerings. In open data markets, data consumers will be able to give back part of the additional value generated to the data owners. However, privacy becomes a significant issue when data that can be used to derive extremely personal information is being traded. This paper discusses why privacy matters in the IoT domain in general and especially in open data markets and surveys existing privacy-preserving strategies and design techniques that can be used to facilitate end to end privacy for open data markets. We also highlight some of the major research challenges that need to be address in order to make the vision of open data markets a reality through ensuring the privacy of stakeholders.
PCR based detection of Phomopsis vexans (Sacc. & Syd.) - The causative agent of leaf blight and fruit rot disease of Brinjal (Solanum melongena L.)
KM Jayaramaiah,S. Mahadevakumar,AP Charith Raj,GR Janardhana
International Journal of Life Sciences , 2013, DOI: 10.3126/ijls.v7i1.8173
Abstract: Leaf blight and fruit rot disease of brinjal ( Solanum melongena ) caused by the fungal pathogen Phomopsis vexans is the most prevailing diseases responsible for the significant yield loss in many Brinjal growing regions of India. The survey conducted during 2008-2010, seven (07) isolates of Phomopsis vexans causing leaf blight and fruit rot disease in different areas of Karnataka were isolated, identified and confirmed by Koch’s postulates. Identification of Phomopsis vexans by conventional culture method was time consuming and laborious. Hence, PCR based detection assay was used to detect the pathogen from DNA samples obtained from fungal isolates. Universal primer pairs designed from internal transcribed spacer regions ITS1 (5'-CGGATCTCTTGGTTCTGGCA-3') and ITS4 (5'-GACGCTCGAACAGGCATGCC-3') of the ribosomal DNA (rDNA) of the genus Phomopsis were used for PCR. The study revealed the amplification of expected 553bp PCR products in all the DNA samples isolated from different isolates of Phomopsis vexans confirming their association in leaf blight and fruit rot disease of Brinjal. DOI: http://dx.doi.org/10.3126/ijls.v7i1.8173 International Journal of Life Sciences 7(1): 2013; 17-20
Context-aware Sensor Search, Selection and Ranking Model for Internet of Things Middleware
Charith Perera,Arkady Zaslavsky,Peter Christen,Michael Compton,Dimitrios Georgakopoulos
Computer Science , 2013,
Abstract: As we are moving towards the Internet of Things (IoT), the number of sensors deployed around the world is growing at a rapid pace. Market research has shown a significant growth of sensor deployments over the past decade and has predicted a substantial acceleration of the growth rate in the future. It is also evident that the increasing number of IoT middleware solutions are developed in both research and commercial environments. However, sensor search and selection remain a critical requirement and a challenge. In this paper, we present CASSARAM, a context-aware sensor search, selection, and ranking model for Internet of Things to address the research challenges of selecting sensors when large numbers of sensors with overlapping and sometimes redundant functionality are available. CASSARAM proposes the search and selection of sensors based on user priorities. CASSARAM considers a broad range of characteristics of sensors for search such as reliability, accuracy, battery life just to name a few. Our approach utilises both semantic querying and quantitative reasoning techniques. User priority based weighted Euclidean distance comparison in multidimensional space technique is used to index and rank sensors. Our objectives are to highlight the importance of sensor search in IoT paradigm, identify important characteristics of both sensors and data acquisition processes which help to select sensors, understand how semantic and statistical reasoning can be combined together to address this problem in an efficient manner. We developed a tool called CASSARA to evaluate the proposed model in terms of resource consumption and response time.
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