Biblio

With novel 3D imaging technology based on computed tomography (CT) set to replace the current 2D X-ray systems, airports face the challenge of adequately preparing airport security officers (screeners) through knowledge building. Virtual reality (VR) bears the potential to greatly facilitate this process by allowing learners to experience and engage in immersive virtual scenarios as if they were real. However, while general aspects of immersion have been explored frequently, less is known about the benefits of immersive technology for instructional purposes in practical settings such as airport security.In the present study, we evaluated how different display technologies (2D vs VR) and segmentation (system-paced vs learner-paced) affected screeners' objective and subjective knowledge gain, cognitive load, as well as aspects of motivation and technology acceptance. By employing a 2 x 2 between-subjects design, four experimental groups experienced uniform learning material featuring information about 3D CT technology and its application in airport security: 2D system-paced, 2D learner-paced, VR system-paced, and VR learner-paced. The instructional material was presented as an 11 min multimedia lesson featuring words (i.e., narration, onscreen text) and pictures in dynamic form (i.e., video, animation). Participants of the learner-paced groups were prompted to initialize the next section of the multimedia lesson by pressing a virtual button after short segments of information. Additionally, a control group experiencing no instructional content was included to evaluate the effectiveness of the instructional material. The data was collected at an international airport with screeners having no prior 3D CT experience (n=162).The results show main effects on segmentation for objective learning outcomes (favoring system-paced), germane cognitive load on display technology (supporting 2D). These results contradict the expected benefits of VR and segmentation, respectively. Overall, the present study offers valuable insight on how to implement instructional material for a practical setting.

Recently literature indicates that stack based three-dimensional (3D) integration techniques may bring in new security vulnerabilities, such as new attack surfaces for hardware Trojan (HT) insertion. Compared to its two-dimensional counterpart (2DHTs), a 3D hardware Trojan (3DHT) could be stealthily distributed in multiple tiers in a single 3D chip. Although the comprehensive models for 3DHTs are available in recent work, there still lacks 3DHT detection and mitigation methods, especially run-time countermeasures against 3DHTs. This work proposes to leverage the 3D communication infrastructure, 3D network-on-chips (NoCs), to tackle the cross-tier hardware Trojans in stacked multi-tier chips. An invariance checking method is further proposed to detect the Trojans that induce malicious NoC packets or facilitate information leak. The proposed method is successfully deployed in NoC routers and achieves a Trojan detection rate of over 94%. The synthesis result of a hardened router at a 45nm technology node shows that the proposed invariance checking only increases the area by 6.49% and consumes 3.76% more dynamic power than an existing 3D router. The NoC protected with the proposed method is applied to the image authentication in a 3D system. The case study indicates that the proposed security measure reduces the correlation coefficient by up to 31% over the baseline.

Multicast on-chip communication is encountered in various cache-coherence protocols targeting multi-core processors, and its pervasiveness is increasing due to the proliferation of machine learning accelerators. In-network handling of multicast traffic imposes additional switching-level restrictions to guarantee deadlock freedom, while it stresses the allocation efficiency of Network-on-Chip (NoC) routers. In this work, we propose a novel NoC router microarchitecture, called SmartFork, which employs a versatile and cost-efficient multicast packet replication scheme that allows the design of high-throughput and low-cost NoCs. The design is adapted to the average branch splitting observed in real-world multicast routing algorithms. Compared to state-of-the-art NoC multicast approaches, SmartFork is demonstrated to yield higher performance in terms of latency and throughput, while still offering a cost-effective implementation.

Due to the steady growth of various sophisticated types of malware, different malware analysis systems are becoming more and more demanded. While there are various automatic approaches available to identify and detect malware, the malware analysis is still time-consuming process. The visualization-driven techniques may significantly increase the efficiency of the malware analysis process by involving human visual system which is a powerful pattern seeker. In this paper the authors reviewed different visualization methods, examined their features and tasks solved with their help. The paper presents the most commonly used approaches and discusses open challenges in malware visual analytics.

The use of modeling techniques such as Knuth's Rule or Bayesian Blocks for the purposes of real-time traffic characterization in RFID networks has been proposed already. This study examines the applicability of using Voronoi polygon maps or alternatively, DBSCAN clustering, as initial density estimation techniques when computing 2-Dimentional Bayesian Blocks models of RFID traffic. Our results are useful for the purposes of extending the constant-piecewise adaptation of Bayesian Blocks into 2D piecewise models for the purposes of more precise detection of anomalies in RFID traffic based on multiple log features such as command type, location, UID values, security support, etc. Automatic anomaly detection of RFID networks is an essential first step in the implementation of intrusion detection as well as a timely response to equipment malfunction such as tag hardware failure.

Layer assignment, a major step in global routing of integrated circuits, is usually performed to assign segments of nets to multiple layers. Besides the traditional optimization goals such as overflow and via count, interconnect delay plays an important role in determining chip performance and has been attracting much attention in recent years. Accordingly, in this paper, we propose MiniDelay, a timing-aware layer assignment algorithm to minimize delay for advanced technology nodes, taking both wire congestion and coupling effect into account. MiniDelay consists of the following three key techniques: 1) a non-default-rule routing technique is adopted to reduce the delay of timing critical nets, 2) an effective congestion assessment method is proposed to optimize delay of nets and via count simultaneously, and 3) a net scalpel technique is proposed to further reduce the maximum delay of nets, so that the chip performance can be improved in a global manner. Experimental results on multiple benchmarks confirm that the proposed algorithm leads to lower delay and few vias, while achieving the best solution quality among the existing algorithms with the shortest runtime.

In this paper, we study the resilient vector consensus problem in multi-agent networks and improve resilience guarantees of existing algorithms. In resilient vector consensus, agents update their states, which are vectors in ℝd, by locally interacting with other agents some of which might be adversarial. The main objective is to ensure that normal (non-adversarial) agents converge at a common state that lies in the convex hull of their initial states. Currently, resilient vector consensus algorithms, such as approximate distributed robust convergence (ADRC) are based on the idea that to update states in each time step, every normal node needs to compute a point that lies in the convex hull of its normal neighbors' states. To compute such a point, the idea of Tverberg partition is typically used, which is computationally hard. Approximation algorithms for Tverberg partition negatively impact the resilience guarantees of consensus algorithm. To deal with this issue, we propose to use the idea of centerpoint, which is an extension of median in higher dimensions, instead of Tverberg partition. We show that the resilience of such algorithms to adversarial nodes is improved if we use the notion of centerpoint. Furthermore, using centerpoint provides a better characterization of the necessary and sufficient conditions guaranteeing resilient vector consensus. We analyze these conditions in two, three, and higher dimensions separately. We also numerically evaluate the performance of our approach.

We study the attribution problem for deep networks applied to perception tasks. For vision tasks, attribution techniques attribute the prediction of a network to the pixels of the input image. We propose a new technique called Blur Integrated Gradients (Blur IG). This technique has several advantages over other methods. First, it can tell at what scale a network recognizes an object. It produces scores in the scale/frequency dimension, that we find captures interesting phenomena. Second, it satisfies the scale-space axioms, which imply that it employs perturbations that are free of artifact. We therefore produce explanations that are cleaner and consistent with the operation of deep networks. Third, it eliminates the need for baseline parameter for Integrated Gradients for perception tasks. This is desirable because the choice of baseline has a significant effect on the explanations. We compare the proposed technique against previous techniques and demonstrate application on three tasks: ImageNet object recognition, Diabetic Retinopathy prediction, and AudioSet audio event identification. Code and examples are at https://github.com/PAIR-code/saliency.

In this study, it was aimed to recognize the emotional state from facial images using the deep learning method. In the study, which was approved by the ethics committee, a custom data set was created using videos taken from 20 male and 20 female participants while simulating 7 different facial expressions (happy, sad, surprised, angry, disgusted, scared, and neutral). Firstly, obtained videos were divided into image frames, and then face images were segmented using the Haar library from image frames. The size of the custom data set obtained after the image preprocessing is more than 25 thousand images. The proposed convolutional neural network (CNN) architecture which is mimics of LeNet architecture has been trained with this custom dataset. According to the proposed CNN architecture experiment results, the training loss was found as 0.0115, the training accuracy was found as 99.62%, the validation loss was 0.0109, and the validation accuracy was 99.71%.

This paper proposes an advanced scheme of message security in 3D cover images using multiple layers of security. Cryptography using AES-256 is implemented in the first layer. In the second layer, edge detection is applied. Finally, LSB steganography is executed in the third layer. The efficiency of the proposed scheme is measured using a number of performance metrics. For instance, mean square error (MSE), peak signal-to-noise ratio (PSNR), structural similarity index measure (SSIM), mean absolute error (MAE) and entropy.

ARtect is an Augmented Reality application developed with Unity 3D, which envisions an educational interactive and immersive tool for architects, designers, researchers, and artists. This digital instrument renders the competency to visualize custom-made 3D models and 2D graphics in interior and exterior environments. The user-friendly interface offers an accurate insight before the materialization of any architectural project, enabling evaluation of the design proposal. This practice could be integrated into learning architectural design process, saving resources of printed drawings, and 3D carton models during several stages of spatial conception.

The availability of commercial fully immersive virtual reality systems allows the proposal and development of new applications that offer novel ways to visualize and interact with multidimensional neuroimaging data. We propose a system for the visualization and interaction with Magnetic Resonance Imaging (MRI) scans in a fully immersive learning environment in virtual reality. The system extracts the different slices from a DICOM file and presents the slices in a 3D environment where the user can display and rotate the MRI scan, and select the clipping plane in all the possible orientations. The 3D environment includes two parts: 1) a cube that displays the MRI scan in 3D and 2) three panels that include the axial, sagittal, and coronal views, where it is possible to directly access a desired slice. In addition, the environment includes a representation of the brain where it is possible to access and browse directly through the slices with the controller. This application can be used both for educational purposes as an immersive learning tool, and by neuroscience researchers as a more convenient way to browse through an MRI scan to better analyze 3D data.

Neural Style Transfer based on convolutional neural networks has produced visually appealing results for image and video data in the recent years where e.g. the content of a photo and the style of a painting are merged to a novel piece of digital art. In practical engineering development, we utilize 3D objects as standard for optimizing digital shapes. Since these objects can be represented as binary 3D voxel representation, we propose to extend the Neural Style Transfer method to 3D geometries in analogy to 2D pixel representations. In a series of experiments, we first evaluate traditional Neural Style Transfer on 2D binary monochromatic images. We show that this method produces reasonable results on binary images lacking color information and even improve them by introducing a standardized Gram matrix based loss function for style. For an application of Neural Style Transfer on 3D voxel primitives, we trained several classifier networks demonstrating the importance of a meaningful convolutional network architecture. The standardization of the Gram matrix again strongly contributes to visually improved, less noisy results. We conclude that Neural Style Transfer extended by a standardization of the Gram matrix is a promising approach for generating novel 3D voxelized objects and expect future improvements with increasing graphics memory availability for finer object resolutions.

We propose a novel visualization technique (Eagle-Eye) for intrusion detection, which visualizes a host as a commu- nity of system call traces in two-dimensional space. The goal of EagleEye is to visually cluster the system call traces. Although human eyes can easily perceive anomalies using EagleEye view, we propose two different methods called SAM and CPM that use the concept of data depth to help administrators distinguish between normal and abnormal behaviors. Our experimental results conducted on Australian Defence Force Academy Linux Dataset (ADFA-LD), which is a modern system calls dataset that includes new exploits and attacks on various programs, show EagleEye's efficiency in detecting diverse exploits and attacks.

Biometric recognition systems based on ultrasound images have been investigated for several decades, and nowadays ultrasonic fingerprint sensors are fully integrated in portable devices. Main advantage of the Ultrasound over other technologies are the possibility to collect 3D images, allowing to gain information on under-skin features, which improve recognition accuracy and resistance to spoofing. Also, ultrasound images are not sensible to several skin contaminations, humidity and not uniform ambient illumination. An ultrasound system, able to acquire 3D images of the human palm has been recently proposed. In this work, a recognition procedure based on 2D palmprint images collected with this system is proposed and evaluated through verification experiments carried out on a home made database composed of 141 samples collected from 24 users. Perspective of the proposed method by upgrading the recognition procedure to provide a 3D template able to accounts for palm lines' depth are finally highlighted and discussed.

This paper explores the benefits of 3D face modeling for in-the-wild facial expression recognition (FER). Since there is limited in-the-wild 3D FER dataset, we first construct 3D facial data from available 2D dataset using recent advances in 3D face reconstruction. The 3D facial geometry representation is then extracted by deep learning technique. In addition, we also take advantage of manipulating the 3D face, such as using 2D projected images of 3D face as additional input for FER. These features are then fused with that of 2D FER typical network. By doing so, despite using common approaches, we achieve a competent recognition accuracy on Real-World Affective Faces (RAF) database and Static Facial Expressions in the Wild (SFEW 2.0) compared with the state-of-the-art reports. To the best of our knowledge, this is the first time such a deep learning combination of 3D and 2D facial modalities is presented in the context of in-the-wild FER.

This work presents the design and implementation of a large curved display system in a virtual reality (VR) environment that supports visualization of 2D datasets (e.g., images, buttons and text). By using this system, users are allowed to interact with data in front of a wide field of view and gain a high level of perceived immersion. We exhibit two use cases of this system, including (1) a virtual image wall as the display component of a 3D user interface, and (2) an inventory interface for a VR-based educational game. The use cases demonstrate capability and flexibility of curved displays in supporting varied purposes of data interaction within virtual environments.

Cross-modal hashing, which searches nearest neighbors across different modalities in the Hamming space, has become a popular technique to overcome the storage and computation barrier in multimedia retrieval recently. Although dozens of cross-modal hashing algorithms are proposed to yield compact binary code representation, applying exhaustive search in a large-scale dataset is impractical for the real-time purpose, and the Hamming distance computation suffers inaccurate results. In this paper, we propose a novel index scheme over binary hash codes in cross-modal retrieval. The proposed indexing scheme exploits a few binary bits of the hash code as the index code. Based on the index code representation, we construct an inverted index structure to accelerate the retrieval efficiency and train a neural network to improve the indexing accuracy. Experiments are performed on two benchmark datasets for retrieval across image and text modalities, where hash codes are generated by three cross-modal hashing methods. Results show the proposed method effectively boosts the performance over the benchmark datasets and hash methods.

Two-factor authentication has been widely used due to the vulnerabilities associated with the traditional password-based authentication. One-Time Password (OTP) plays an important role in authentication protocol. However, a variety of security problems have been challenging the security of OTP, and improvements are introduced to solve it. This paper reviews several schemes to implement and modify the OTP, a comparison among the popular OTP algorithms is presented. A smart grid architecture with edge computing is shown. The authentication techniques in the smart grid are analyzed.

Surface acoustic wave (SAW) optical sensor based on two-dimensional (2D) sensing layer can always provide extremely high sensitivity. As an attractive option, the application of exfoliated 2D perovskite on acousto-optic coupling optical sensor is investigated. In this work, exfoliated 2D (PEA)2PbI4 sheet was transferred as a sensing layer onto the delay area of a dual-port SAW resonator with resonant frequency 497 MHz. From the response under 532 nm laser with intensity of 0.9 mW/cm2, a largest frequency shift of 13.92 MHz was observed. The ultrahigh sensitivity up to 31.6 ppm/(μW/cm2) was calculated by experiment results. We also carried out theoretical analysis and finite element simulation of 3D model to demonstrate the mechanism and validity for optical sensing. The fabricated optical sensor expressed great potential for a variety of optical applications.

A 2D-Compressive Sensing and hyper-chaos based image compression-encryption algorithm is proposed. The 2D image is compressively sampled and encrypted using two measurement matrices. A chaos based measurement matrix construction is employed. The construction of the measurement matrix is controlled by the initial and control parameters of the chaotic system, which are used as the secret key for encryption. The linear measurements of the sparse coefficients of the image are then subjected to a hyper-chaos based diffusion which results in the cipher image. Numerical simulation and security analysis are performed to verify the validity and reliability of the proposed algorithm.

Security often requires that the data must be kept safe from unauthorized access. And the best line of speech communication is security. However, most computers are interconnected with each other openly, thereby exposing them and the communication channels that person uses. Speech cryptography secures information by protecting its confidentiality. It can also be used to protect information about the integrity and authenticity of data. Stronger cryptographic techniques are needed to ensure the integrity of data stored on a machine that may be infected or under attack. So far speech cryptography is used in many forms but using it with Audio file is another stronger technique. The process of cryptography happens with audio file for transferring more secure sensitive data. The audio file is encrypted and decrypted by using Lorenz 3D mapping and then 3D mapping function is converted into 2D mapping function by using euler's numerical resolution and strong algorithm provided by using henon mapping and then decrypted by using reverse of encryption. By implementing this, the resultant audio file will be in secured form.

``Style transfer'' among images has recently emerged as a very active research topic, fuelled by the power of convolution neural networks (CNNs), and has become fast a very popular technology in social media. This paper investigates the analogous problem in the audio domain: How to transfer the style of a reference audio signal to a target audio content? We propose a flexible framework for the task, which uses a sound texture model to extract statistics characterizing the reference audio style, followed by an optimization-based audio texture synthesis to modify the target content. In contrast to mainstream optimization-based visual transfer method, the proposed process is initialized by the target content instead of random noise and the optimized loss is only about texture, not structure. These differences proved key for audio style transfer in our experiments. In order to extract features of interest, we investigate different architectures, whether pre-trained on other tasks, as done in image style transfer, or engineered based on the human auditory system. Experimental results on different types of audio signal confirm the potential of the proposed approach.

With the advent of QR readers and mobile phones the use of graphical codes like QR codes and data matrix code has become very popular. Despite the noise like appearance, it has the advantage of high data capacity, damage resistance and fast decoding robustness. The proposed system embeds the image chosen by the user to develop visually appealing QR codes with improved decoding robustness using BCH algorithm. The QR information bits are encoded into luminance value of the input image. The developed Picode can inspire perceptivity in multimedia applications and can ensure data security for instances like online payments. The system is implemented on Matlab and ARM cortex A8.

This article deals with the estimation of magnet losses in a permanent-magnet motor inserted in a nut-runner. This type of machine has interesting features such as being two-pole, slot-less and running at a high speed (30000 rpm). Two analytical models were chosen from the literature. A numerical estimation of the losses with 2D Finite Element Method was carried out. A detailed investigation of the effect of simulation settings (e.g., mesh size, time-step, remanence flux density in the magnet, superposition of the losses, etc.) was performed. Finally, calculation of losses with 3D-FEM were also run in order to compare the calculated losses with both analytical and 2D-FEM results. The estimation of the losses focuses on a range of frequencies between 10 and 100 kHz.