Personalized PageRank (PPR) is a typical similarity metric between nodes in a graph, and node searches based on PPR are widely used. In many applications, graphs change dynamically, and in such cases, it is desirable to perform ad hoc searches based on PPR. An ad hoc search involves performing searches by varying the search parameters or graphs. However, as the size of a graph increases, the computation cost of performing an ad hoc search can become excessive. In this paper, we propose a method called Castanet that offers fast ad hoc searches of PPR. The proposed method features (1) iterative estimation of the upper and lower bounds of PPR scores, and (2) dynamic pruning of nodes that are not needed to obtain a search result. Experiments confirm that the proposed method does offer faster ad hoc PPR searches than existing methods.

Iterative channel estimation and decoding receivers have evolved over the years, most especially with Turbo and LPDC codes. Nevertheless, few works have determined the performance of symbol level Reed-Solomon (RS) codes in iterative receiver structures. The iterative channel estimation and symbol level RS decoding receiver structure found in literature concentrate on M-QAM systems over flat Rayleigh fading channels. In this paper, attention is focused on the performance of RS codes in iterative channel estimation and decoding receiver structures for Orthogonal Frequency Division Multiplexing (OFDM) systems on frequency-selective Rayleigh fading channels. Firstly, the paper extends the Koetter and Vardy (KV) RS iterative receiver structure over flat Rayleigh fading channels to frequency-selective Rayleigh fading channels. In addition, the paper develops a symbol level RS iterative receiver structure for OFDM systems on frequency-selective Rayleigh fading channels based on the Parity-check matrix Transformation Algorithm (PTA). The performance of the RS-KV and RS-PTA iterative receiver structures for OFDM systems are documented through computer simulation. The simulation results verify that both iterative receiver structures are suitable for real time RS OFDM wireless applications. The results also show that the developed RS-PTA iterative receiver structure is a low complexity and high performance alternative to the RS-KV iterative receiver structure.

In this paper, robust stability of nonlinear feedback systems with unknown disturbance is considered by using the operator-based right coprime factorization method. For dealing with the unknown disturbance, a new design scheme and a nonlinear controller are given. That is, robust stability of the nonlinear systems with unknown disturbance is guaranteed by combining right coprime factorization with the proposed controller. Simultaneously, adverse effects resulting from the disturbance are removed by using the proposed nonlinear operator controller. Finally, a simulation example is given to show the effectiveness of the proposed design scheme of this paper.

Fault tolerance is an important feature for the system LSIs used in reliability-critical systems. Although redundancy techniques are generally used to provide fault tolerance, these techniques have significantly hardware costs. However, FPGAs can easily provide high reliability due to their reconfiguration ability. Even if faults occur, the implemented circuit can perform correctly by reconfiguring to a fault-free region of the FPGA. In this paper, we examine an FPGA-IP core loaded in SoC and introduce a fault-tolerant technology based on fault detection and recovery as a CAD-level approach. To detect fault position, we add a route to the manufacturing test method proposed in earlier research and identify fault areas. Furthermore, we perform fault recovery at the logic tile and multiplexer levels using reconfiguration. The evaluation results for the FPGA-IP core loaded in the system LSI demonstrate that it was able to completely identify and avoid fault areas relative to the faults in the routing area.

This letter presents a Preferable Mad-y (PMad-y) turn model and Low-cost Adaptive and Fault-tolerant Routing (LAFR) method that use one and two virtual channels along the X and Y dimensions for 2D mesh Network-on-Chip (NoC). Applying PMad-y rules and using the link status of neighbor routers within 2-hops, LAFR can tolerate multiple faulty links and routers in more complicated faulty situations and impose the reliability of network without losing the performance of network. Simulation results show that LAFR achieves better saturation throughput (0.98% on average) than those of other fault-tolerant routing methods and maintains high reliability of more than 99.56% on average. For achieving 100% reliability of network, a Preferable LAFR (PLAFR) is proposed.

The compressive sensing (CS) theory has been widely used in synthetic aperture radar (SAR) imaging for its ability to reconstruct image from an extremely small set of measurements than what is generally considered necessary. Because block-based CS approaches in SAR imaging always cause block boundaries between two adjacent blocks, resulting in namely the block artefacts. In this paper, we propose a weighted overlapped block-based compressive sensing (WOBCS) method to reduce the block artefacts and accomplish SAR imaging. It has two main characteristics: 1) the strategy of sensing small and recovering big and 2) adaptive weighting technique among overlapped blocks. This proposed method is implemented by the well-known CS recovery schemes like orthogonal matching pursuit (OMP) and BCS-SPL. Promising results are demonstrated through several experiments.

In this work, we study efficient scheduling with network coding in a scalable video coding (SVC) multicast system. Transmission consists of two stages. The original SVC packets are multicasted by the server in the first stage and the lost packets are retransmitted in the second stage. With deadline constraint, the consumer can be only satisfied when the requested packets are received before expiration. Further, the hierarchical encoding architecture of SVC introduces extra decoding delay which poses a challenge for providing acceptable reconstructed video quality. To solve these problems, instantly decodable network coding is applied for reducing the decoding delay, and a novel packet weighted policy is designed to better describe the contribution a packet can make in upgrading the recovered video quality. Finally, an online packet scheduling algorithm based on the maximal weighted clique is proposed to improve the delay, deadline miss ratio and users' experience. Multiple characteristics of SVC packets, such as the packet utility, the slack time and the number of undelivered/wanted packets, are jointly considered. Simulation results prove that the proposed algorithm requires fewer retransmissions and achieves lower deadline miss ratio. Moreover, the algorithm enjoys fine recovery video quality and provides high user satisfaction.

Timing fault detection techniques address the problems caused by increased variations on a chip, especially with dynamic voltage and frequency scaling (DVFS). The Razor flip-flop (FF) is a timing fault detection technique that employs double sampling by the main and shadow FFs. In order for the Razor FF to correctly detect a timing fault, not the main FF but the shadow FF must sample the correct value. The application of Razor FFs to static logic relaxes the timing constraints; however, the naive application of Razor FFs to dynamic precharged logic such as SRAM read circuits is not effective. This is because the SRAM precharge cannot start before the shadow FF samples the value; otherwise, the transition of the bitline of the SRAM stops and the value sampled by the shadow FF will be incorrect. Therefore, the detect period cannot overlap the precharge period. This paper proposes a novel application of Razor FFs to SRAM read circuits. Our proposal employs a conditional precharge according to the value of a bitline sampled by the main FF. This enables the detect period to overlap the precharge period, thereby relaxing the timing constraints. The additional circuit required by this method is simple and only needed around the sense amplifier, and there is no need for a clock delayed from the system clock. Consequently, the area overhead of the proposed circuit is negligible. This paper presents SPICE simulations of the proposed circuit. Our proposal reduces the minimum cycle time by 51.5% at a supply voltage of 1.1 V and the minimum voltage by 31.8% at cycle time of 412.5 ps.

The differential fault analysis of SOSEMNAUK was presented in Africacrypt in 2011. In this paper, we improve previous work with algebraic techniques which can result in a considerable reduction not only in the number of fault injections but also in time complexity. First, we propose an enhanced method to determine the fault position with a success rate up to 99% based on the single-word fault model. Then, instead of following the design of SOSEMANUK at word levels, we view SOSEMANUK at bit levels during the fault analysis and calculate most components of SOSEMANUK as bit-oriented. We show how to build algebraic equations for SOSEMANUK and how to represent the injected faults in bit-level. Finally, an SAT solver is exploited to solve the combined equations to recover the secret inner state. The results of simulations on a PC show that the full 384 bits initial inner state of SOSEMANUK can be recovered with only 15 fault injections in 3.97h.

In this paper we study a recently proposed variant of the facility location problem, called the r-gathering problem. Given an integer r, a set C of customers, a set F of facilities, and a connecting cost co(c, f) for each pair of c ∈ C and f ∈ F, an r-gathering of customers C to facilities F is an assignment A of C to open facilities F' ⊆ F such that at least r customers are assigned to each open facility. We give an algorithm to find an r-gathering with the minimum cost, where the cost is maxc ∈ C{co(c, A(c))}, when all C and F are on the real line.

This work reports a novel power-rail electrostatic discharge (ESD) clamp circuit with parasitic bipolar-junction-transistor (BJT) and channel parallel shunt paths. The parallel shunt paths are formed by delivering a tiny ratio of drain voltage to the gate terminal of the clamp device in ESD events. Under such a mechanism, the proposed circuit achieves enhanced robustness over those of both gate-grounded NMOS (ggNMOS) and the referenced gate-coupled NMOS (gcNMOS). Besides, the proposed circuit also achieves improved fast power-up immunity over that of the referenced gcNMOS. All investigated designs are fabricated in a 65-nm CMOS process. Transmission-line-pulsing (TLP) and human-body-model (HBM) test results have both confirmed the performance enhancements of the proposed circuit. Finally, the validity of the achieved performance enhancements on other trigger circuits is essentially revealed in this work.

In this paper, we present two classes of zero difference balanced (ZDB) functions, which are derived by difference balanced functions, and a class of perfect ternary sequences respectively. The proposed functions have parameters not covered in the literature, and can be used to design optimal constant composition codes, and perfect difference systems of sets.

Link duplication is widely used in Internet protocol networks to tackle the network congestion increase caused by link failure. Network congestion represents the highest link utilization over all the links in the network. Due to capital expenditure constraints, not every link can be duplicated to reduce congestion after a link fails. Giving priority to some selected links makes sense. Meanwhile, traffic routes are determined by link weights that are configured in advance. Therefore, choosing an appropriate set of link weights reduces the number of links that actually need to be duplicated in order to keep a manageable congestion under failure. A manageable congestion is a congestion under which Service Level Agreements can be met. The conventional scheme fixes link weights before determining links to duplicate. In this scheme, the fixed link weights are optimized to minimize the worst network congestion. The worst network congestion is the highest network congestion over all the single non-duplicated link failures. As the selection of links for protection depends on the fixed link weights, some suitable protection patterns, which are not considered with other possible link weights, might be skipped leading to overprotection. The paper proposes a scheme that considers multiple protection scenarios before optimizing link weights in order to reduce the overall number of protected links. Simulation results show that the proposed scheme uses fewer link protections compared to the conventional scheme.

In this letter, we propose a novel method for face hallucination by learning a new distance metric in the low-resolution (LR) patch space (source space). Local patch-based face hallucination methods usually assume that the two manifolds formed by LR and high-resolution (HR) image patches have similar local geometry. However, this assumption does not hold well in practice. Motivated by metric learning in machine learning, we propose to learn a new distance metric in the source space, under the supervision of the true local geometry in the target space (HR patch space). The learned new metric gives more freedom to the presentation of local geometry in the source space, and thus the local geometries of source and target space turn to be more consistent. Experiments conducted on two datasets demonstrate that the proposed method is superior to the state-of-the-art face hallucination and image super-resolution (SR) methods.

This letter presents a method for solving several linear equations in max-plus algebra. The essential part of these equations is reduced to constraint satisfaction problems compatible with mixed integer programming. This method is flexible, compared with optimization methods, and suitable for scheduling of certain discrete event systems.

A statistical call admission control (CAC) allows more calls with on-off patterns to be accepted and a higher channel efficiency to be achieved. In this paper, we propose three statistical CACs for VoIP calls with silence suppression considering the priority of each VoIP call, where the call priority is determined by the call acceptance order in an IP-PBX. We analyse the packet loss rates in an IP-PBX under the proposed strategies and express the end-to-end QoS of a VoIP call as an R-factor in a VoIP service network. The performances of the proposed CACs are evaluated using the maximum allowable number of VoIP calls while satisfying the end-to-end QoS constraint, the average QoS of acceptable VoIP calls and the channel efficiency. The advantage of the proposed statistical CACs over the non-statistical CAC is verified in terms of these three performance metrics. The results indicate that a trade-off is possible in that the maximum allowable number of VoIP calls in an IP-PBX increases as the average QoS of acceptable VoIP calls is lowered according to the proposed statistical CAC used. Nevertheless, the results allow us to verify that the channel efficiencies are the same for all the statistical CACs considered.

Wafers with smooth Au thin films (rms surface roughness: < 0.5nm, thickness: < 50nm) were successfully bonded in ambient air at room temperature after an Ar radio frequency plasma activation process. The room temperature bonded glass wafers without any heat treatment showed a sufficiently high die-shear strength of 47-70MPa. Transmission electron microscopy observations showed that direct bonding on the atomic scale was achieved. This surface-activated bonding method is expected to be a useful technique for future heterogeneous photonic integration.

Active oxygen species (AOS), e.g., excited singlet oxygen atom [O(1D)], excited singlet oxygen molecules (1O2), ground-state oxygen atom [O(3P)] and hydroxyl radical (OH), generated under two wavelengths (185 and 254 nm) of ultraviolet (UV) light were exposed to polyethylene (PE), polypropylene (PP) and polystyrene (PS) sheets. We investigated effects of the AOS exposure on the surface modification of these polymer sheets. Nonwoven sheet was used for the surface modification to eliminate an effect of the UV light irradiation. Although hydrophobicity of the PE and PP surfaces was maintained, the PS was changed into the hydrophilic surface.

In this paper we use equivalent circuits to analyze the wavelengths in a Fast and Slow wave Waffle-iron Ridge Guide (FS-WRG). An equivalent circuit for the transverse direction is employed and the transverse resonance method is used to determine the fast wave wavelength. Another equivalent circuit, for the inserted series reactance in the waveguide, is employed for the fast and slow wave wavelength. We also discuss the physical system that determines the wavelengths and the accuracy of this analysis by comparing the wavelengths with those calculated by EM-simulation. Furthermore, we demonstrate use of the results obtained in designing an array antenna.

In recent years, the reduced cost and increased capacity of memory have resulted in a growing number of buffers in switches and routers. Consequently, today's networks suffer from bufferbloat, a term that refers to excess frame buffering resulting in high latency, high jitter, and low throughput. Although ring aggregation is an efficient topology for forwarding traffic from multiple, widely deployed user nodes to a core network, a fairness scheme is needed to achieve throughput fairness and avoid bufferbloat, because frames are forwarded along ring nodes. N Rate N+1 Color Marking (NRN+1CM) was proposed to achieve per-flow fairness in ring aggregation networks. The key idea of NRN+1CM is to assign a color that indicates the dropping priority of a frame according to the flow-input rate. When congestion occurs, frames are selectively discarded based on their color and the frame-dropping threshold. Through the notification process for the frame-dropping threshold, frames are discarded at upstream nodes in advance, avoiding the accumulation of a queuing delay. The performance of NRN+1CM was analyzed theoretically and evaluated with computer simulations. However, its ability to avoid bufferbloat has not yet been proven mathematically. This paper uses an M(n)/M/1/K queue model to demonstrate how bufferbloat is avoided with NRN+1CM's frame-dropping threshold-notification process. The M(n)/M/1/K queue is an M/M/1/K queuing system with balking. The state probabilities and average queue size of each ring node were calculated with the model, proving that the average queue size is suppressed in several frames, but not in the most congested queue. Computer simulation results confirm the validity of the queue model. Consequently, it was logically deducted from the proposed M(n)/M/1/K model that bufferbloat is successfully avoided with NRN+1CM independent of the network conditions including the number of nodes, buffer sizes, and the number and types of flows.