Selective Scheme Research Articles

Aided Opportunistic Jammer Selection for Secrecy Improvement in Underlay Cognitive Radio Networks

In this paper, we consider the physical-layer security for the primary system in an underlay cognitive radio model which comprises of a primary source–destination pair, a secondary receiver (SR), K secondary transmitters (STi, i = 1,…,K) and an eavesdropper (E). To protecting the transmission confidentiality of the primary transmission system against eavesdropping, we propose secondary transmitter (ST) aided opportunistic jamming transmission protocols. In our protocols, the selection of ST plays a crucial role. To this end, we propose the optimal secondary transmission selection (OSTS) and the Optimal Cooperative Jammer Selection (OCJS), respectively. For the non-security management, OSTS, OCJS schemes, we derive the closed-form expressions of the outage probability and the intercept probability for primary system, respectively. Furthermore, we also derive the closed-form expressions of the outage probability for the secondary user for the selective schemes. Numerical results show that the OCJS scheme has the best security performance and the conventional non-security management scheme has the worst security performance for primary system. In addition, the outage performances of OSTS and OCJS are better than the conventional non-security protocol in high secondary transmitting SNR region.

Frequency selective coherence transfer NMR spectroscopy to study the structural dynamics of high molecular weight proteins.

Multidimensional nuclear magnetic resonance (NMR) spectroscopy has enabled detailed characterizations of protein structures and dynamics that are closely linked to functions. However, it leads to a large sensitivity loss in applications to high molecular weight proteins, which is caused by spin relaxation during the frequency discrimination period in the indirect dimension. Here, we describe a selective coherence transfer scheme, which enables us to selectively observe 1H nuclei bonded to 15N or 13C nuclei with specified resonance frequencies. By utilizing this scheme, we achieved a 2.5- to 6-fold increase in signal height per unit of time with this scheme by avoiding the relaxation loss in the indirect dimension, as compared to the conventional two-dimensional heteronuclear correlation spectroscopy. We also demonstrated the effectiveness of this approach with applications to the membrane protein KirBac1.1, and characterized the functionally relevant conformational exchange process in both detergent micelles and a reconstituted membrane environment, corresponding to the apparent molecular masses of 220 kDa and 300 kDa, respectively.

Performance of Random Access Markov Modelling for Two-Way Buffer-Aided Relaying Networks with Wireless Assisted Links

In this paper, we consider two-way relaying networks (TWRNs) in which information of two users randomly exchange via buffer-aided relay. We assume that all nodes work on half-duplex decode-and-forward for relaying of data packets. The relay is equipped with two finite-size buffers and both the users know the exact number of data packets. The data packets are scheduling with different channel access probabilities to avoid collision at relay. The protocols are developed on the basis of selective transmission scheme with states of Markov chain at relay for buffer state information (BSI) and Hybrid buffer state information/channel state information (BSI/CSI). On the basis of these protocols, we investigate closed-from expressions of maximum achievable sum throughput and end-to-end throughput for TWRNs. The numerical results are obtained with the help of CVX software package. Our proposed scheme significantly outperforms the existing two-way buffer-aided relaying scheme in literature.

In-cell determination of Lactate Dehydrogenase Activity in a Luminal Breast Cancer Model ⁻ ex vivo Investigation of Excised Xenograft Tumor Slices Using dDNP Hyperpolarized [1-13C]pyruvate.

[1-13C]pyruvate, the most widely used compound in dissolution-dynamic nuclear polarization (dDNP) magnetic resonance (MR), enables the visualization of lactate dehydrogenase (LDH) activity. This activity had been demonstrated in a wide variety of cancer models, ranging from cultured cells, to xenograft models, to human tumors in situ. Here we quantified the LDH activity in precision cut tumor slices (PCTS) of breast cancer xenografts. The Michigan Cancer Foundation-7 (MCF7) cell-line was chosen as a model for the luminal breast cancer type which is hormone responsive and is highly prevalent. The LDH activity, which was manifested as [1-13C]lactate production in the tumor slices, ranged between 3.8 and 6.1 nmole/nmole adenosine tri-phosphate (ATP) in 1 min (average 4.6 ± 1.0) on three different experimental set-ups consisting of arrested vs. continuous perfusion and non-selective and selective RF pulsation schemes and combinations thereof. This rate was converted to an expected LDH activity in a mass ranging between 3.3 and 5.2 µmole/g in 1 min, using the ATP level of these tumors. This indicated the likely utility of this approach in clinical dDNP of the human breast and may be useful as guidance for treatment response assessment in a large number of tumor types and therapies ex vivo.

Selective branch prediction schemes based on FPGA MIPS processor for educational purposes

Processor performance is measured by amount of ILP (Instruction Level Parallelism) represented by its design. this parallelism is limited by the execution of conditional branch instructions which may break the flow of the program execution. To overcome this problem, several ways were suggested in order to predict both the direction of instructions execution and the address of the instruction to be executed next. In this paper, a design for a dynamic branch predictor was implemented in VHDL (VHSIC Hardware Description Language) then it was integrated with FPGA (Field Programmable Gate Arrays) MIPS (Microprocessor without Interlocked Pipelined Stages) processor and its ability to increase prediction accuracy and MIPS processor performance was approved. This predictor combines gshare and bimodal branch prediction techniques by dividing the PHT (Pattern History Table) into two branch streams corresponding to taken and not-taken states. This combined branch predictor was synthesized using the XILINX ISE (Integrated Software Environment) Design Suite 14.7 tool.

ASGR: An Artificial Spider-Web-Based Geographic Routing in Heterogeneous Vehicular Networks

Recently, vehicular ad hoc networks (VANETs) have been attracting significant attention for their potential for guaranteeing road safety and improving traffic comfort. Due to high mobility and frequent link disconnections, it becomes quite challenging to establish a reliable route for delivering packets in VANETs. To deal with these challenges, an artificial spider geographic routing in urban VAENTs (ASGR) is proposed in this paper. First, from the point of bionic view, we construct the spider web based on the network topology to initially select the feasible paths to the destination using artificial spiders. Next, the connection-quality model and transmission-latency model are established to generate the routing selection metric to choose the best route from all the feasible paths. At last, a selective forwarding scheme is presented to effectively forward the packets in the selected route, by taking into account the nodal movement and signal propagation characteristics. Finally, we implement our protocol on NS2 with different complexity maps and simulation parameters. Numerical results demonstrate that, compared with the existing schemes, when the packets generate speed, the number of vehicles and number of connections are varying, our proposed ASGR still performs best in terms of packet delivery ratio and average transmission delay with an up to 15% and 94% improvement, respectively.

Applications of Non-Uniquely Decodable Codes to Privacy-Preserving High-Entropy Data Representation

Non-uniquely-decodable (non-UD) codes can be defined as the codes that cannot be uniquely decoded without additional disambiguation information. These are mainly the class of non–prefix–free codes, where a code-word can be a prefix of other(s), and thus, the code-word boundary information is essential for correct decoding. Due to their inherent unique decodability problem, such non-UD codes have not received much attention except a few studies, in which using compressed data structures to represent the disambiguation information efficiently had been previously proposed. It had been shown before that the compression ratio can get quite close to Huffman/Arithmetic codes with an additional capability of providing direct access in compressed data, which is a missing feature in the regular Huffman codes. In this study we investigate non-UD codes in another dimension addressing the privacy of the high-entropy data. We particularly focus on such massive volumes, where typical examples are encoded video or similar multimedia files. Representation of such a volume with non–UD coding creates two elements as the disambiguation information and the payload, where decoding the original data from these elements becomes hard when one of them is missing. We make use of this observation for privacy concerns. and study the space consumption as well as the hardness of that decoding. We conclude that non-uniquely-decodable codes can be an alternative to selective encryption schemes that aim to secure only part of the data when data is huge. We provide a freely available software implementation of the proposed scheme as well.

Dual-View Three-Dimensional Display Based on Direct-Projection Integral Imaging with Convex Mirror Arrays

Dual three-dimensional (3-D) view displays have been attracting much attention in many practical application fields since they can provide two kinds of realistic 3-D images with different perspectives to the viewer. Thus, in this paper, a new type of the dual-view 3-D display system based on direct-projection integral imaging using a convex-mirror-array (CMA) is proposed. Two elemental image arrays (EIAs) captured from each of the two 3-D objects are synthesized into a single dual-view EIA (DV-EIA) with a selective sub-image mapping scheme. The divergent beam of the projector containing the information of the DV-EIA is projected onto the CMA. On each convex mirror of the CMA, left and right-view components of the DV-EIA are separated and reflected back into their viewing directions. Two different 3-D scene images are then integrated and displayed on their respective viewing zones. Ray-optical analysis with the parallel-ray-approximation method and experiments with the test 3-D objects on the implemented 22″ DV 3-D display prototype confirm the feasibility of the proposed system in the practical application

Current-Based Out-of-Step Detection Method to Enhance Line Differential Protection

Line differential protection provides the most selective protection scheme for transmission lines. It has an acceptable performance in situations which are challenging for the legacy distance protection. Following large disturbances, two or more areas of a power system may lose their synchronism and go out of step (OOS) which appears often as unstable power swings in some transmission lines. Existing OOS detection methods are based on the impedance trajectory seen by distance relays and conventional line differential protection cannot detect this condition. This paper introduces a new OOS detection method using the current phasors measured at both ends of a transmission line. Rigorous mathematical analyses and illustrated simulation study results are presented to substantiate the efficiency of the proposed method. The obtained results approve that the proposed method can be served as an efficient OOS detection method for line differential protection schemes.

A Harmonic Based Pilot Protection Scheme for VSC-MTDC Grids with PWM Converters

This paper presents a selective harmonic-based pilot protection scheme for detecting faults happened in the DC transmission section of VSC-MTDC grids with pulse width modulation (PWM) voltage source converters (VSCs). When a DC fault occurs in VSC-MTDC grids with PWM converters, first carrier frequency harmonic (FCFH) currents will be generated by all VSCs through the grid. FCFH currents have different flowing directions depending on the characteristics and the location of the fault. According to the characteristics of the existing FCFH in the fault currents, a selective pilot protection algorithm is designed for VSC-MTDC grids. Considering the internal and external DC transmission faults for specific zones, and the circulating flow of FCFH current in the DC link capacitors, the relays cannot detect FCFH currents for external faults, while for the internal faults, FCFH currents are clearly detected. To design the selective protection algorithm, Hilbert-Huang transform (HHT) is used to detect the instantaneous frequency and the instantaneous amplitude of the high frequency intrinsic mode function (IMF)s, which are extracted from the fault current waves. Multiple faults with different characteristics are applied to CIGRE DCS-2 VSC-MTDC grid with two-level and three-level VSCs modeled in PSCAD, and the HHT-based selective protection scheme is designed in MATLAB. According to the results, the proposed algorithm can truly discriminate between internal and external faults.

Lightweight Cipher for H.264 Videos in the Internet of Multimedia Things with Encryption Space Ratio Diagnostics.

Within an Internet of Multimedia Things, the risk of disclosing streamed video content, such as that arising from video surveillance, is of heightened concern. This leads to the encryption of that content. To reduce the overhead and the lack of flexibility arising from full encryption of the content, a good number of selective-encryption algorithms have been proposed in the last decade. Some of them have limitations, in terms of: significant delay due to computational cost, or excess memory utilization, or, despite being energy efficient, not providing a satisfactory level of confidentiality, due to their simplicity. To address such limitations, this paper presents a lightweight selective encryption scheme, in which encoder syntax elements are encrypted with the innovative EXPer (extended permutation with exclusive OR). The selected syntax elements are taken from the final stage of video encoding that is during the entropy coding stage. As a diagnostic tool, the Encryption Space Ratio measures encoding complexity of the video relative to the level of encryption so as to judge the success of the encryption process, according to entropy coder. A detailed comparative analysis of EXPer with other state-of-the-art encryption algorithms confirms that EXPer provides significant confidentiality with a small computational cost and a negligible encryption bitrate overhead. Thus, the results demonstrate that the proposed security scheme is a suitable choice for constrained devices in an Internet of Multimedia Things environment.

Comparison between PI, PR+HC, and modified PR+HC current controller in inverter system

<span>This paper presents the comparison between proportional integral (PI) current controller, proportional resonance and harmonic compensator (PR+HC) current controller and modified PR+HC current controller in the inverter system. Power electronic components like inverter and current controller uses in the system produce unwanted harmonics that affect the quality of distribution power network. In this study, development and simulation of current controller using conventional proportional integral (PI), the selective harmonic compensation scheme (PR+HC), and modified version of the latter are considered so to overcome these harmonics injection. Modification is by adding control parameter randomisation technique to the PR+HC scheme. Results compare the three controllers and proved that with modification to the selective harmonic compensation scheme, the overall current THD can be reduced</span>

Prioritised and selective power control in cellular wireless networks

Power control is used in cellular communications systems to reduce power consumption and satisfy as many users as possible by managing the mutual interference between users. In signal to interference plus noise ratio (SINR) tracking power control (TPC) schemes, all users are required to adjust their power levels for each iteration, which is inefficient. In this study, a prioritised and selective uplink power control scheme is proposed. Priority user requirements are satisfied first, and then as many normal users (NUs) as possible are satisfied with their target SINRs. In addition, if an NU is currently satisfied with its target SINR, it is not required to update its transmit power level. Conversely, NUs who are not satisfied update their power levels. Simulation results are presented, which show that the proposed scheme outperforms dynamic target SINR TPC and variable target SINR TPC in terms of power consumption and efficiency. In addition, the proposed scheme is better than target SINR TPC and opportunistic power control as the number of users increases.

Redio: Accelerating Disk-Based Graph Processing by Reducing Disk I/Os

Disk-based graph systems store part or all of graph data on external devices like hard drives or SSDs, achieving scalability without excessive hardware. However, massive expensive disk I/Os remain the major performance bottleneck of disk-based graph processing. In this paper, we propose Redio, a new approach to accelerating disk-based graph processing by reducing disk I/Os. First, Redio observes that it is feasible to accommodate all vertex states in main memory and this can eliminate almost all vertex-related disk I/Os. Second, Redio introduces a dynamic selective scheduling scheme to identify inactive edges in each iteration and skip them when and only when such skipping can bring performance benefit. To improve its effectiveness, Redioin corporates a compact edge storage to improve data locality and an indexed bitmap to minimize its memory and computation overheads. We have implemented a single-node prototype for Redio under the edge-centric computation model. Extensive experiments show that Redio consistently outperforms well-known edge-centric disk-based systems in all experiments, delivering an average speedup of $4.33\times$ on HDDs and $5.33\times$ on SSDs over the fastest among them (i.e., GridGraph). Experimental results also show that Redio delivers an average speedup of $3.13\times$ on HDDs and $1.28\times$ on SSDs over the fastest among representative vertex-centric disk-based systems (i.e., FlashGraph).

Hybrid Precoding Design for Adaptive Subconnected Structures in Millimeter-Wave MIMO Systems

Hybrid precoding design for an adaptive subconnected structure offers a compromise between hardware complexity and spectral efficiency in massive multiple-input multiple-output (MIMO) systems at millimeter-wave (mmWave) frequencies. This paper focuses on the impacts of the partial antenna connections on the achievable sum-rate (ASR) performance for the uniform linear array and uniform square planar array configurations in mmWave networks. The subarray architectures consist of the overlapped, interlaced, and dynamically selective subset schemes in mmWave MIMO systems. Notably, on the basis of the ASR maximization, the Gram–Schmidt (GS)-based antenna selection (AS) algorithm is used to acquire an appropriate antenna subset and magnificently simplifies the radio frequency chain–antenna mapping operation in the sequel. Finally, simulation results demonstrate that an adaptive subarray architecture in conjunction with the GS-based AS search strategy is able to accomplish the ASR performance approaching the fully connected architecture with an alleviated demand on both computation and hardware complexities.

Low temperature epitaxial growth of Ge:B and Ge0.99Sn0.01:B source/drain for Ge pMOS devices: in-situ and conformal B-doping, selectivity towards oxide and nitride with no need for any post-epi activation treatment

We report on production compatible low temperature (≤320 °C) selective epitaxial growth schemes for boron doped Ge0.99Sn0.01 and Ge in source/drain areas of FinFET and gate-all-around (GAA) strained-Ge pMOS transistors. Active B concentrations are as high as 3.2 × 1020 cm−3 and 2.2 × 1020 cm−3 for Ge0.99Sn0.01 and Ge, respectively. The Ge:B growth is based on a cyclic deposition and etch approach using Cl2 as an etchant, while the Ge0.99Sn0.01:B growth is selective in nature. Low Ti/p+ Ge(Sn):B contact resistivities of 3.6 × 10−9 Ω cm2 (Ge0.99Sn0.01) and 5.5 × 10−9 Ω cm2 (Ge:B) have been obtained without any post-epi activation anneal. This work is the first demonstration of a selective, conformally doped Ge1−xSnx:B source/drain epi implemented on Ge FinFET device structure with fin widths down to 10 nm and on GAA devices (horizontal compressively strained-Ge nanowires).

Efficient protection using chaos for Context-Adaptive Binary Arithmetic Coding in H.264/Advanced Video Coding

Recently, video encryption has been widely investigated to enhance the protection for video data, yet the encryption efficiency may not be considered sufficiently so that some encryption schemes are unsuitable for the real-time applications. In this paper, we propose a novel chaotic selective encryption scheme (CSES) based on Context-Adaptive Binary Arithmetic Coding (CABAC) of H.264/Advanced Video Coding (H.264/AVC) for the practical applications. To satisfy the secure and real-time requirement, we select the important and sensitive encryption objects on the basis of the analysis of syntax elements in CABAC. According to the characteristics of chosen syntax elements, two encryption methods combined with two designed chaos-based key stream generators (KSGs) are presented in CSES to implement the video encryption with the reasonable and acceptable compression and encryption performance. The experimental results and security analysis demonstrate that the proposed CSES with the format-compliance has the good confidentiality and can resist some common security attacks, such as the brute force attack, histogram attack, information entropy attack, replacement attack and some other common attacks. It can be found from the comparison experiments about the encryption efficiency that our CSES has the higher real-time performance. The comparison analysis with other video encryption methods illustrates that the proposed CSES is more suitable for the practical applications.

Selective image registration for efficient visual SLAM on planar surface structures in underwater environment

This paper presents a computationally efficient approach that can be applied to visual simultaneous localization and mapping (SLAM) for the autonomous inspection of underwater structures using monocular vision. A selective image registration scheme consisting of key-frame selection and key-pair selection is proposed to effectively use visual features that may not be evenly distributed on the surface of underwater structures. The computational cost of the visual SLAM algorithm can be substantially reduced using only potentially effective images and image pairs by applying the proposed image registration scheme. The performance of the proposed approach is demonstrated on two different experimental datasets obtained using autonomous underwater vehicles.

Insights into the C Distribution in Si:C/Si:C:P and the Annealing Behavior of Si:C Layers

Si:C and Si:C:P alloys are potential candidates for source-drain stressor applications in n-type Fin Field Effect Transistors (FinFETs). Increasing the C content to achieve high strain results in the arrangement of C atoms as third nearest neighbors (3nn) in the Si:C lattice. During thermal annealing, the presence of C atoms as 3nn may promote clustering at the interstitial sites, causing loss of stress. The concentration of C atoms as 3nn is reduced by the incorporation of a small amount of Ge atoms during the growth, whereas in-situ P doping does not influence this 3nn distribution [J Solid State Sci. Technol vol 6, p 755, 2017]. Small amounts of Ge are provided during low temperature selective epitaxial growth scheme, which are based on cyclic deposition and etching (CDE). In this work, we aim to provide physical insights into the aforementioned phenomena, to understand the behavior of 3nn C atoms and the types of defects that are formed in the annealed Si:C films. Using ab-initio simulations, the Ge-C interaction in the Si matrix is investigated and this insight is used to explain how the Ge incorporation leads to a reduced 3nn distribution of the C atoms. The interaction between C and P in the Si:C:P films is also investigated to explain why the P incorporation has not led to a reduction in the 3nn distribution. We then report on the Raman characterization of Si:C layers subjected to post epi annealing. As the penetration depth of the laser is dependent on the wavelength, Raman measurements at two different wavelengths enable us to probe the depth distribution of 3nn C atoms after applying different annealing conditions. We observed a homogeneous loss in 3nn C throughout the layer. Whereas in the kinematic modeling of high resolution X-ray diffraction spectra, a gradient in the substitutional C loss was observed close to the epitaxial layer/substrate interface. This gradient can be due to the out diffusion of C atoms into the Si substrate or to the formation of interstitial C clusters, which cannot be distinguished in HR-XRD. Deep Level Transient Spectroscopy indicated that the prominent out-diffusing species was interstitial CO complex while the interstitial C defects were also prevalent in the epi layer.

PAPR Reduction of a Universal Filtered Multicarrier Using a Selective Mapping Scheme

The new generation of wireless communication systems involves several different technologies. The universal filtered multicarrier (UFMC) is one of these technologies. UFMC supports various numerology designs; however, the high peak to average power ratio (PAPR) is a major limitation faced by designers. Therefore, diverse approaches have been introduced, such as amplitude clipping, tone reservation, and active constellation extension, to mitigate the PAPR problem. These algorithms produce significant degradation in terms of bit error rate or power consumption. Another proposed solution is multiple signal representation schemes, which have promised to conserve bit error rate performance without power waste. Selected mapping is a multiple signal representation technique that reduces the PAPR without bit error degradation. This paper focuses on integrating the selected mapping method with the UFMC. Simulation results show that the integrated algorithm presents better PAPR performance: the PAPR was reduced by 2.1 dB and 1 dB for UFMC and CP-OFDM, respectively, without bit error rate degradation.