Detectors

We investigate the performance of an automatic frequency control loop operating in a receiver for linearly modulated digital signals. The loop uses a balanced quadricorrelator as a frequency detector, and we address the design of such a detector for optimum loop tracking performance. This problem involves the analysis of the disturbances generated in the quadricorrelator, which are conveniently divided into self-noise and thermal-noise-induced components. It is shown that the quadricorrelator can be designed so as to make selfnoise negligible in the steady state, both with staggered and nonstaggered modulations. This leaves the thermal-noise-induced components as the sole obstacle to loop operation in the tracking mode. The level of such components is then minimized by further selection of the quadricorrelator filters. Numerical examples are worked out to assess the advantages of optimized quadricorrelators over more conventional schemes. It is found that tracking errors can be substantially reduced with no penalty for frequency acquisition times of the loop.

This paper discusses the design and implementation of frequency offset estimation algorithms for DOCSIS upstream channels. A cost-effective estimator which approaches the Cramer-Rao bound for high SNRs is derived. The effect of ISI generated by upstream micro-reflections in typical cable networks is considered, and a condition upon the transmitted preamble sequence which guarantees unbiased estimation is presented. It is shown

We report an ultracompact label-free biosensor that uses a vertical-cavity surface-emitting laser (VCSEL)-based measurement system for the characterization of biomolecular interactions. It consists of a VCSEL, a plastic guided-mode resonant filter, and two p-in detectors. The system has demonstrated very high sensitivity to molecules on top of the sensor.

A novel feature region selection method for robust digital image watermarking is proposed in this paper. This method aims to select a nonoverlapping feature region set, which has the greatest robustness against various attacks and can preserve image quality as much as possible after watermarked. It first performs a simulated attacking procedure using some predefined attacks to evaluate the robustness of every candidate feature region. According to the evaluation results, it then adopts a track-with-pruning procedure to search a minimal primary feature set which can resist the most predefined attacks. In order to enhance its resistance to undefined attacks under the constraint of preserving image quality, the primary feature set is then extended by adding into some auxiliary feature regions. This work is formulated as a multidimensional knapsack problem and solved by a genetic algorithm based approach. The experimental results for StirMark attacks on some benchmark images support our expectation that the primary feature set can resist all the predefined attacks and its extension can enhance the robustness against undefined attacks. Comparing with some well-known feature-based methods, the proposed method exhibits better performance in robust digital watermarking.

In this work, we present a method for approximating constrained maximum entropy (ME) reconstructions of SPECT data with modifications to a block-iterative maximum a posteriori (MAP) algorithm. Maximum likelihood (ML)-based reconstruction algorithms require some form of noise smoothing. Constrained ME provides a more formal method of noise smoothing without requiring the user to select parameters. In the context of SPECT, constrained ME seeks the minimum-information image estimate among those whose projections are a given distance from the noisy measured data, with that distance determined by the magnitude of the Poisson noise. Images that meet the distance criterion are referred to as feasible images. We find that modeling of all principal degrading factors (attenuation, detector response, and scatter) in the reconstruction is critical because feasibility is not meaningful unless the projection model is as accurate as possible. Because the constrained ME solution is the same as a MAP solution for a particular value of the MAP weighting parameter, beta, the constrained ME solution can be found with a MAP algorithm if the correct value of beta is found. We show that the RBI-MAP algorithm, if used with a dynamic scheme for estimating beta, can approximate constrained ME solutions in 20 or fewer iterations. We compare results for various methods of achieving feasible images on a simulation of Tl-201 cardiac SPECT data. Results show that the RBI-MAP ME approximation provides images and quantitative estimates close to those from a slower algorithm that gives the true ME solution. Also, we find that the ME results have higher spatial resolution and greater high-frequency noise content than a feasibility-based stopping rule, feasibility-based low-pass filtering, and a quadratic Gibbs prior with beta selected according to the feasibility criterion. We conclude that fast ME approximation is possible using either RBI-MAP with the dynamic procedure or a feasibility-based stopping rule, and that such reconstructions may be particularly useful in applications where resolution is critical.

This paper presents a new Design for Testability (DFT) technique for Current-Mode Logic (CML) circuits. This new technique, with little overhead, using built-in detectors, monitors all gate output swings and flags all abnormal voltage excursions. These detectors cover classes of faults that cannot be tested by stuck-at testing methods only. Circuit simulations have shown that abnormal gate output excursions caused by the presence of a defect are common with CML. We also show that this technique works well below "at-speed" frequencies. Finally, variants of the built-in detectors with reduced area overhead are proposed.

A new capacitance sensor system was developed with a microcontroller, commercial humidity and temperature sensors, a capacitance-to-digital converter, and a custom-built capacitance sensor. The performance of the system was evaluated by simulation and testing of the prototype. The impact of variations of ambient conditions on the system performance was analyzed, and a model for correcting the humidity and temperature influence was developed. Based on the experimental results obtained in an uncontrolled environment using a standard capacitor of 1 pF, the 24-h stability of the system was estimated to be within 30 parts in 10 6 . The high stability and sensitivity of the system allow its effective use in object-detection applications. Several sensors were constructed and evaluated while sensing various materials under different scenarios.

Intravenous (IV) therapy has been included as an integral part of nurse's professional practice. Although it is an effective curing technique, it has some complications. Air embolism is one of such complications which may cause death of patients in some cases. In this paper, we have proposed an efficient, economic and reliable air embolism protecting system to save precious lives in case of air bubble insertion. The proposed system monitors the IV tube and when an air bubble even in fraction of millimeter gets introduced into the tube, detects it, indicates emergency and blocks the fluid flow to protect entrance of the air bubble into the human body. The proposed system has been evaluated on various IV solutions; results are very promising as the accuracy is more than or equal to 99% in every case thus supporting the implementation of the solution. Therefore, the system can be used for any type of IV solution.

Amphibious vehicles have long been recognized as important logistic tools for the armed forces. The ability to provide a single vehicle supply line over land and water make them the most direct, adaptable, and cost effective method for re-supply operations. Historically, amphibious vehicles were optimized for either traversing aquatic or terrestrial environments leading to vehicles that lacked all-round performance and were often unreliable and thus less effective tools for the military. Using modern technology, the DUKW 21 design team's object was to develop a viable amphibious transport vehicle that was as much at home in the water as on land. The DUKW 21 project design delivers a new amphibious transport vehicle concept capable of delivering a 20-foot fully loaded ISO container from a position 5 nm at sea to a point 5 nm in land at a minimum cruising speed of 15 knots. It also has the ability to do this autonomously by incorporating an array of sensor and guidance systems leading to lower manning levels. After initial stability, resistance, and mechanical system analysis, it was determined the DUKW 21 is a feasible design. The DUKW 21 has the ability to meet the main design requirements with currently available technology and do so with minimal subsystems and complexity.

hannel coding is an error-control technique used for providing robust data transmission through imperfect channels by adding redundancy to the data. There are two important classes of such coding methods: block and convolutional. For this tutorial, we focus on linear block codes because they provide much insight and allow for a simple visualization of the error detection/correction process. Forward error correction (FEC) is the name used when the receiving equipment does most of the work. In the case of block codes, the decoder looks for errors and, once detected, corrects them (according to the capability of the code). The technique has become an important signal-processing tool used in modern communication systems and in a wide variety of other digital applications such as high-density memory and recording media. Such coding provides system performance improvements at significantly lower cost than through the use of other methods that increase signal-to-noise ratio (SNR) such as increased power or antenna gain. In this article we first develop the ideas behind simple binary codes. We then treat cyclic and nonbinary An intuitive treatment of error detection and correction

A new technique of color detection based on time-resolved charge collection during transient response measurement using a hydrogenated amorphous silicon detector has been proposed and experimentally demonstrated. The method based on the material intrinsic wavelength-filtering properties is implemented in color sensing by transient response of a detector to a combination of basic colors light and voltage pulse. Resulting transient responses under different illumination and bias voltage conditions confirm considerable accuracy of proposed method. In particular, the best agreement of measured and calculated transient response curves has been obtained by using the spectral response of all three primary colors in calculations. It was observed that the presence of blue light drastically reduces the transient response to a chromatic light illumination. Finally, a voltage pulse influence to the basic colors transient response was found.

In this paper, we present a low-complexity, near maximum-likelihood (ML) performance achieving detector for large MIMO systems having tens of transmit and receive antennas. Such large MIMO systems are of interest because of the high spectral efficiencies possible in such systems. The proposed detection algorithm, termed as multistage likelihood-ascent search (M-LAS) algorithm, is rooted in Hopfield neural networks, and is shown to possess excellent performance as well as complexity attributes. In terms of performance, in a 64 × 64 V-BLAST system with 4-QAM, the proposed algorithm achieves an uncoded BER of 10 −3 at an SNR of just about 1 dB away from AWGN-only SISO performance given by Q( √ SNR). In terms of coded BER, with a rate-3/4 turbo code at a spectral efficiency of 96 bps/Hz the algorithm performs close to within about 4.5 dB from theoretical capacity, which is remarkable in terms of both high spectral efficiency as well as nearness to theoretical capacity. Our simulation results show that the above performance is achieved with a complexity of just O(NtNr) per symbol, where Nt and Nr denote the number of transmit and receive antennas.

We demonstrate the measurement of optical frequency differences between Q-switched laser pulses by using photo-electromotive-force (photo-EMF) optical frequency sensors. The presence of high-peak-power laser pulses affords the photo-EMF frequency sensor with ultrafast response times limited only by the free-carrier lifetime of the sensor material. Such fast response times lead to a broad dynamic range for optical difference frequency measurements with an experimentally demonstrated frequency detection bandwidth in excess of 50 MHz, limited only by the capability of our test equipment. Such a large dynamic range for optical frequency detection makes photo-EMF sensors ideal candidates for adaptive remote sensing of high-speed objects.

Geant4 is a very large, highly accurate toolkit for Monte Carlo simulation of particle-matter interaction. It has been applied to high-energy physics, cosmic ray modeling, radiation shields, radiation therapy, mine detection, and other areas. Geant4 is being used to help design some high energy physics experiments (notably CMS and Atlas) to be run on the future large hadron collider: the largest particle collider in the world. The parallelization, ParGeant4, represents a challenge due to the unique characteristics of Geant4: (i) complex object-oriented design; (ii) intrinsic use of templates and abstract classes to be instantiated later by the end user; (iii) large program with many developers; and (iv) frequent releases. The key issue for parallelization is not just how to parallelize "correctly" but also how to parallelize "with minimum effort". In addition, the parallelization should make as few assumptions about the source code as possible, due to the frequent release schedule of Geant4. We use TOP-C (Task Oriented Parallel C/C++) for parallelization and Marshalgen for marshaling/serialization. In some examples on a cluster of 100 nodes yielded a speedup of up to 94.4. The code's portability, scalability and performance are also discussed.

Corner detection is widely used in image processing and machine vision. Hence, different corner detectors are proposed. But the performance of such corner detectors is sensitive to round effect and curve shape of the edges. In this paper we propose a novel corner detector that either over come corner detection problems and produces some information about detected corners that is very useful in segmentation and object recognition.

This paper presents time-of-occurrence (phase) distributions of individual pulsating partial discharges (PDs) which occur in a pointdielectric gap in air for ac voltage conditions. It is determined that the pulse phase distribution is adequately modeled by a normal (Gaussian) distribution. Based on such best-fit normal distributions, estimated mean values of the phase and the standard deviations are given for the individual PD pulse distributions. For the alternating voltage case, the spread of time-of-occurrence distributions of succeeding pulses are universally broader than that of preceding pulses. PD pulse separations are non-uniform in phase. Further, if one assumes the usual sinusoidal waveform, then the voltage separation of PD pulses are also seen to be non-uniform.

Image representation using bag of visual words approach is commonly used in image classification. Features are extracted from images and clustered into a visual vocabulary. Images can then be represented as a normalized histogram of visual words similarly to textual documents represented as a weighted vector of terms. As a result, text categorization techniques are applicable to image classification. In this paper, our contribution is twofold. First, we propose a suitable Term-Frequency and Inverse Document Frequency weighting scheme to characterize the importance of visual words. Second, we present a method to fuse different bag-of-words obtained with different vocabularies. We show that using our tf.idf normalization and the fusion leads to better classification rates than other normalization methods, other fusion schemes or other approaches evaluated on the SIMPLIcity collection.

This letter proposes a modification to the Least-Significant-Bit (LSB) matching, a steganographic method for embedding message bits into a still image. In the LSB matching the choice of whether to add or subtract one from the cover image pixel is random. The new method uses the choice to set a binary function of two cover pixels to the desired value. The value of the binary function is used to carry information. Therefore, the modified method allows embedding the same payload as LSB matching, but with fewer changes to the cover image.

Several commercial GaAlAs and InGaAsP injection lasers have been investigated with respect to their photodetection properties. The responsivity of the laser diode detectors is in the 0.15-0.25 AIW range and the dark current ranges from 5 nA to 500 nA at 3-V reverse bias. The high frequency performance of a laser diode detector strongly depends on the laser structure. The bandwidth is determined by the capacitance of the lasers and ranges from 70 MHz to 1.3 GHz. The structure showing the fastest response was the TJS laser due to its low junction capacitance. OF LASER DIODE DETECTORS 1665 * *

Face to face communication is a real-time process operating at a a time scale in the order of 40 milliseconds. The level of uncertainty at this time scale is considerable, making it necessary for humans and machines to rely on sensory rich perceptual primitives rather than slow symbolic inference processes. In this paper we present progress on one such perceptual primitive. The system automatically detects frontal faces in the video stream and codes them with respect to 7 dimensions in real time: neutral, anger, disgust, fear, joy, sadness, surprise. The face finder employs a cascade of feature detectors trained with boosting techniques . The expression recognizer receives image patches located by the face detector. A Gabor representation of the patch is formed and then processed by a bank of SVM classifiers. A novel combination of Adaboost and SVM's enhances performance. The system was tested on the Cohn-Kanade dataset of posed facial expressions . The generalization performance to new subjects for a 7way forced choice correct. Most interestingly the outputs of the classifier change smoothly as a function of time, providing a potentially valuable representation to code facial expression dynamics in a fully automatic and unobtrusive manner. The system has been deployed on a wide variety of platforms including Sony's Aibo pet robot, ATR's RoboVie, and CU animator, and is currently being evaluated for applications including automatic reading tutors, assessment of human-robot interaction.

1. Introduction to observational methods, 2. Coding schemes and observational measurement, 3. Recording observational data, 4. Representing observational data, 5. Observer agreement and Cohen's kappa, 6. Kappas for point-by-point agreement, 7. The intraclass ...

Since Robotics is the field concerned with the connection of perception to action, Artificial Intelligence must have a central role in Robotics if the connection is to be intelligent. Artificial Intelligence addresses the crucial questions of: what knowledge is required in any aspect of thinking; ...

The aim of this paper is to present an acquisition system and experimental measurements of a new micromachined Thermal Conductivity Detector (µTCD), applied downstream of a gas-chromatography (GC) system. We describe simple and innovative electronics for sensor control and data acquisition, outlining the relevant resistance control, native imbalance compensation and automatic gain control (AGC) algorithm. Measurements and sensitivity tests have been carried out by connecting our TCD and acquisition system downstream of the microfluidic section and GC column of a commercial GC system. Comparing the results with those of a complete commercial GC system we observed a similar response and noise. Sensitivity measurements on toluene masses gave very good results, having observed a sensitivity of 15.2±0.6 µVs/ng. This high sensitivity paves the way for using the µTCD in many portable applications like in-line quality control, industrial security and safety. We also show the good operation of the AGC algorithm.

The development of energy selective, photon counting X-ray detectors allows for a wide range of new possibilities in the area of computed tomographic image formation. Under the assumption of perfect energy resolution, here we propose a tensor-based iterative algorithm that simultaneously reconstructs the X-ray attenuation distribution for each energy. We use a multi-linear image model rather than a more standard "stacked vector" representation in order to develop novel tensor-based regularizers. Specifically, we model the multi-spectral unknown as a 3-way tensor where the first two dimensions are space and the 3 rd dimension is energy. This approach allows for the design of tensor nuclear norm regularizers, which like its two dimensional counterpart, is a convex function of the multi-spectral unknown. The solution to the resulting convex optimization problem is obtained using an alternating direction method of multipliers (ADMM) approach. Simulation results shows that the generalized tensor nuclear norm can be used as a stand alone regularization technique for the energy selective (spectral) computed tomography (CT) problem and when combined with total variation regularization it enhances the regularization capabilities especially at low energy images where the effects of noise are most prominent.

Information flow in a telecommunication network is accomplished through the interaction of mechanisms at various design layers with the end goal of supporting the information exchange needs of the applications. In wireless networks in particular, the different layers interact in a nontrivial manner in order to support information transfer. In this text we will present abstract models that capture the cross-layer interaction from the physical to transport layer in wireless network architectures including cellular, ad-hoc and sensor networks as well as hybrid wireless-wireline. The model allows for arbitrary network topologies as well as traffic forwarding modes, including datagrams and virtual circuits. Furthermore the time varying nature of a wireless network, due either to fading channels or to changing connectivity due to mobility, is adequately captured in our model to allow for state dependent network control policies. Quantitative performance measures that capture the quality of service requirements in these systems depending on the supported applications are discussed, including throughput maximization, energy consumption minimization, rate utility function maximization as well as general performance functionals. Cross-layer control algorithms with optimal or suboptimal performance with respect to the above measures are presented and analyzed. A detailed exposition of the related analysis and design techniques is provided.

In this paper a fractal analysis study of VoIP traffic is presented. The characteristics of measured VoIP traffic on both call and packet level have been investigated. The results support the popular Poisson process for VoIP call arrival modeling but we argue that the call holding times follow heavy-tailed distributions rather than exponential distributions. We propose the generalized Pareto distribution for modeling the call holding times. At the packet level we have found that the exponential modeling of On and Off periods is also inappropriate and heavy-tailed characteristics have been identified in case of all the investigated VoIP codecs. The generalized Pareto distribution can be used as an accurate model for the On and Off periods too. In the analysis we revealed that the aggregated VoIP traffic has fractal characteristics and we suggest the fractional Gaussian noise model for the aggregated VoIP traffic.

Özetçe -Bu bildiride, Zemax 13 yazılımı aracılıgı ile görünür ışık haberleşmesi (visible light communication, VLC) kanalları karakterize edilecektir. Yaklaşımımızda, ölçülerini tanımlayacagımız iç mekân ortamı üçboyutlu olarak Zemax 'da oluşturulmakta ve LED tabanlı ışık kaynakları uygun noktalara yerleştirilmektedir. Sözkonusu yazılımım ışın izleme (ray tracing) araçları kullanılarak, alıcı tarafa dogrudan ve dolaylı yollardan (yansımalar) ulaşan sinyallerin gücü ve gecikme süreleri hesaplanmaktadır. Daha sonra bu bilgiler Matlab 'a aktarılarak uygun normalleştirmeler aracılıgı ile bu iç mekan propagasyon ortamına karşılık gelen kanal dürtü cevabı elde edilmektedir. Bu yöntem izlenerek, degişik ebatlardaki odalarda farklı alıcı/verici yerleşimleri varsayımları altında kanal dürtü cevapları elde edilmiş ve gecikme yayılımı, DC kazancı vb kanal parametreleri hesaplanmıştır.

This paper describes a face detection framework that is capable of processing images extremely rapidly while achieving high detection rates. There are three key contributions. The first is the introduction of a new image representation called the "Integral Image" which allows the features used by our detector to be computed very quickly. The second is a simple and efficient classifier which is built using the AdaBoost learning algorithm to select a small number of critical visual features from a very large set of potential features. The third contribution is a method for combining classifiers in a "cascade" which allows background regions of the image to be quickly discarded while spending more computation on promising face-like regions. A set of experiments in the domain of face detection is presented. The system yields face detection performance comparable to the best previous systems . Implemented on a conventional desktop, face detection proceeds at 15 frames per second.

This paper presents a methodology for automating the processingof highway pavement video images using an integration of artificial neural network models with conventional image-processing techniques. The methodology developed is able to classify pavement surface cracking by the type, severity, and extent of cracks detected in video images. The approach is divided into five major steps: (1) image segmentation, which involves reduction of a raw gray-scale pavement image into a binary image, (2) feature extraction, (3) decomposition of the image into tiles and identification of tiles with cracking, (4) integration of the results from step (3) and classification of the type of cracking in each image, and (5) computation of the severities and extents of cracking detected in each image. In this methodology, artificial neural network models are used in automatic thresholding of the images in stage (1) and in the classification stages (3) and (4). The results obtained in each stage of the process are presented and discussed in this paper. The research results demonstrate the feasibility of this new approach for the detection, classification, and quantification of highway pavement surface cracking.

In this paper, a quasi-peak detector mode for a time-domain electromagnetic interference (TDEMI) measurement system is described. Measurements were performed in the 30-1000-MHz range. The digital signal processing of EMI measurements can emulate in real time the modes of conventional analog equipment, e.g., peak, average, rms, and quasi-peak detector. With the presented time-domain measurement system, the measurement time can be reduced by a factor of ten. A novel signal recording routine for TDEMI measurements and quasi-peak detection is described. Measurement results obtained from the investigation of a drill machine, monitor, and laptop obtained with the TDEMI measurement system are discussed. The comparison of the results obtained with the described TDEMI measurement system and measurements performed with a conventional EMI receiver show an average deviation over the whole frequency range less than 3 dB.

The goal of the Laser Interferometric Gravitational-Wave Observatory (LIGO) is to detect and study gravitational waves of astrophysical origin. Direct detection of gravitational waves holds the promise of testing general relativity in the strong-field regime, of providing a new probe of exotic objects such as black hole and neutron stars, and of uncovering unanticipated new astrophysics. LIGO, a joint Caltech-MIT project supported by the National Science Foundation, operates three multi-kilometer interferometers at two widely separated sites in the United States. These detectors are the result of decades of worldwide technology development, design, construction, and commissioning. They are now operating at their design sensitivity, and are sensitive to gravitational wave strains smaller than 1 part in 1E21. With this unprecedented sensitivity, the data are being analyzed to detect or place limits on gravitational waves from a variety of potential astrophysical sources.

Students use mobile-phones to store lecture-materials, e-books, tutorials, videos, communicate with their classmates and browse the internet for exceedingly-different-intentions. These projected-advantages, however, would have potential-undesirable-effects if mobile-phones are utilized in restricted-premises, such as exam-venues. Noncompliant-students (to general University exam-regulations) do use mobile-phones to cheat in exams. The rapid-explosion of cell-phones at the beginning of the 21st Century eventually raised problems, such as their potential-use to invade privacy or contribute to widespread academic-cheating. In this paper, two systems, that will be used, independently, to detect mobile-phones in the exam-venues, were proposed: a mobile-detector with a range of 1.0m, using resistor-capacitor-circuit, which can detect both the incoming and outgoing-calls, as well as video-transmission and text messages, even if a mobile-phone is kept at the silent mode; and a Reed-switch-circuit-scanner, which, responds to an applied-magnetic-field and, can be used to detect mobile-phones that are switched-off or put on flight-mode, and thus, it can be used to scan students (without physical-inspection) on their entering examination-rooms. Overall, the results of this-concise-study are rather-positive, providing a good-starting-point for advanced investigations and improvements of the same. Several future-research-areas were also proposed by the study.

Previously, researchers were trying to replace the copper wires with the optical technology. They used photons instead of electrons to carry out the data within machines. The future of IC industry depends upon the speed and bandwidth requirements, but in metallic interconnections we have constraints on speed as well as bandwidth. With the advancement in computer technology we are now more dependent upon ultra fast data transfer rate between and within chips. Now, we can achieve high speeds with the use of optics, and if we integrate the optical components on a single silicon chip then it would allow the data to flow at a higher speed. This paper reviews the growth of silicon photonics compared to last few years and a promising future of photonics. Intel Corporation first announced its major breakthrough in 2004 based on silicon photonics (Moore's law). They developed a modulator based on silicon that operates at 50GHz. It was 50 times faster than the previous invention. In 2008 Intel declared that the data transfer rate can be increased further up to 1Tbps (bits per second).compatibility of silicon photonics with CMOS fabrication offers great advantages, such as low cost, high volume integration.

Current intrusion detection systems (IDS) generate a large number of specific alerts, but do not provide actionable information. Many times, these alerts must be analyzed by a network defender, a time consuming and tedious task which can occur hours or days after an attack. Improved understanding of the cyberspace domain can lead to great advancements in cyberspace situational awareness research and development. This thesis applies the Cross Industry Standard Process for Data Mining (CRISP-DM) to develop an understanding about a host system under attack. Data is generated by launching scans and exploits at a machine outfitted with a set of hostbased data collectors. Through knowledge discovery, features are identified within the data collected which can be used to enhance host-based intrusion detection. By discovering relationships between the data collected and controlled events, false positive alerts were reduced by over 91% when compared to a leading open source IDS. This method of searching for hidden forensic evidence relationships enhances understanding of novel attacks and vulnerabilities, bolstering ones ability to defend the cyberspace domain. The methodology presented in this thesis, as well as the features identified, can be used to further situational awareness research. iv Dedicated to Grammy and Grampy, who have filled my childhood and beyond with warm and happy memories.

Due to the growing changes in the electrical network related to the new distributed generation scheme and the integration of renewable energy sources, new requirements for grid-connected power converters are being defined in the new grid codes. The injection of positive-and negativesequence current components is becoming necessary for achieving new capabilities like the reactive power injection during a grid fault. This paper deals with a fundamental issue in this topic, i.e., the performance of the current controller. Classical dq controllers, which are extensively used in industrial applications, degrade its performance when both sequences are involved, as unavoidable oscillations in the dq axes appear. In this paper, a new scheme for controlling positive-and negative-sequence currents using dq controllers is proposed, based on an enhanced Double Synchronous Reference Frame (DSRF) controller. In this paper the DSRF controller is improved by adding a decoupling network which counteracts the oscillations caused by the presence of both sequences. Experimental results will demonstrate the validity of the proposed Decoupled DSRF (DDSRF) controller.

Humanitarian demining aims for a total clearance of all types of landmines from infected areas and infrastructures as efficiently and as safely and as rapidly as possible while keeping cost to minimum. It requires that each individual mine in an area to be located, uncovered and removed or destroyed. The focus is to make these areas economically viable and usable by the people for different activities and to allow people to use their land without fear. The targets of mine detection and sensing technologies are to achieve a high probability of detection rate while maintaining low probability of false alarm. But, the probability of false alarm rate is directly proportional to the time and cost of demining by a large factor. Careful study of the limitations of any detection and sensing capabilities with regard to the location, weather, environment, and soil composition is critical along with the required technical operation and maintenance skills, while keeping in mind that not all high-tech solutions may be workable in different soil and environmental conditions. Wide variety of mine detection and sensor technologies has been developed while others are in varying stages of development. But it is clear that no single available technology has the capability to detect and recognize a variety of mines under all situations. Also most of these methods and techniques are very slow, have low accuracy, complex and large in size, andor expensive and suffer from a high false alarm rate. Due to this, some efforts are even trying combinations of various new technologies, and some are combining their new techniques with ordinary metal detectors and other sensors to increase the sensitivity of their particular methods. This paper presents the landmine problems, the problems facing humanitarian demining, priorities and an evaluation of mine detection techniques and technologies along with their new development potential in the context of humanitarian demining.

Plagiarism is one form of academic dishonesty, which is often done by students in programming classes. In a large class, detecting plagiarism manually is both difficult and time-consuming、especially due to the numerous modifications of the source code to conceal the cheating.

The Canny edge detector is a very popular and effective edge feature detector that is used as a pre-processing step in many computer vision algorithms. It is a multi-step detector which performs smoothing and filtering, non-maxima suppression, followed by a connected-component analysis stage to detect "true" edges, while suppressing "false" non edge filter responses. While there have been previous (partial) implementations of the Canny and other edge detectors on GPUs, they have been focussed on the old style GPGPU computing with programming using graphical application layers. Using the more programmer friendly CUDA framework, we are able to implement the entire Canny algorithm. Details are presented along with a comparison with CPU implementations. We also integrate our detector in to MAT-LAB, a popular interactive simulation package often used by researchers. The source code will be made available as open source.

Due to the growing changes in the electrical network related to the new distributed generation scheme and the integration of renewable energy sources, new requirements for grid-connected power converters are being defined in the new grid codes. The injection of positive-and negativesequence current components is becoming necessary for achieving new capabilities like the reactive power injection during a grid fault. This paper deals with a fundamental issue in this topic, i.e., the performance of the current controller. Classical dq controllers, which are extensively used in industrial applications, degrade its performance when both sequences are involved, as unavoidable oscillations in the dq axes appear. In this paper, a new scheme for controlling positive-and negative-sequence currents using dq controllers is proposed, based on an enhanced Double Synchronous Reference Frame (DSRF) controller. In this paper the DSRF controller is improved by adding a decoupling network which counteracts the oscillations caused by the presence of both sequences. Experimental results will demonstrate the validity of the proposed Decoupled DSRF (DDSRF) controller.

Free space optical (FSO) communication is an upgraded supplement to existing wireless technologies. FSO technology leads vast modulation bandwidth, unlicensed spectrum, cost effective deployment, quick redeploy and much more. FSO systems are used to transmit and receive all kind of data at high data rates (up to 100 Gbps). Today researchers are preliminary focused to use the free space communication systems to make their inter satellites links. This paper gives a review on the laser diodes, modulation schemes and the detection techniques which are deployed in the FSO systems.