The manifold-ranking algorithm has been successfully adopted in content-based image retrieval (CBIR) in recent years. However, while the global low-level features are widely utilized in current systems, region-based features have received little attention. In this paper, a novel attention-driven transductive framework based on a hierarchical graph representation is proposed for region-based image retrieval (RBIR). This approach can be characterized by two key properties: (1) Since the issue about region significance is the key problem in region-based retrieval, a visual attention model is chosen here to measure the regions' significance. (2) A hierarchical graph representation which combines region-level with image-level similarities is utilized for the manifold-ranking method. A novel propagation energy function is defined which takes both low-level visual features and regional significance into consideration. Experimental results demonstrate that the proposed approach shows the satisfactory retrieval performance compared to the global-based and the block-based manifold-ranking methods.

VI time responses of a conventional electromagnetic relay during breaking contact operations were measured. In a conventional switching circuit, unstable contact resistance, irregular bouncing, and poor reproducibility were confirmed. Using a transient current switch circuit and two sharpened contact electrodes, bouncing during a breaking operation was suppressed, and unstable contact resistance changes and reproducibility of breaking operation were also improved.

In a D.C.42 V-10A resistive circuit, break arcs are generated between electrical contact pairs. The materials of the contact pairs are Ag, Ag/C 2wt%, Ag/SnO2 12wt%, and Ag/ZnO 12wt%. The arc spectral intensities are measured by a time-resolved spectroscopic temperature measurement system. The arc temperature is calculated from the spectral intensities by using the method of relative intensities of two spectra. The experimental results are as follows. The arc temperature gradually decreases with increase of the gap of electrical contacts. The ranges of arc temperature for Ag, Ag/C 2wt%, Ag/SnO2 12wt%, and Ag/ZnO 12wt% contacts pairs are 4500-11000 K, 4000-6000 K, 4000-7000 K, and 4000-11000 K, respectively.

This paper focuses on the numerical and experimental investigations of the influence of two polymers (PA6 and POM) on the arc behavior during arc motion process. The mathematical model of 3-dimentional air arc plasma considering the ablation of lateral walls is built based on magnetic hydro-dynamics (MHD). By adopting the commercial computational fluid dynamics (CFD) package based on control-volume method, the above MHD model is solved and the distribution of temperature field, concentration field, flow field and electrical potential field in the arc chamber are calculated. The simulation results indicate that the vapor concentration behind the arc column is higher than that in front of the arc column because of the existence of "double vortices" in the arc chamber. The use of polymers causes the maximal arc voltage increase 16.2% with POM and 18.9% with PA6 in this case and causes the average arc velocity increase 15.8% with POM and 21.1% with PA6 in this case. The experiments are also carried out to study the influence of polymers on arc voltage and arc root position in the arc chamber during arc motion. The experimental results prove the validity of the numerical investigation.

An electrical arc is generated by opening the contacts of a relay when the current is above the minimum arc current in a circuit. A magneto-hydrodynamic (MHD) model was employed to simulate this dynamic arcing process. The distributions of arc parameters such as temperature, electrical field and magnetic flux density generated by opening the contacts in a circuit with a 5 A DC low current were obtained. The behaviors of the arc parameters with increasing gap length between the contacts were also simulated. The MHD model was then combined with structured dynamic layering, which is a dynamic meshing technique of computational fluid dynamics (CFD) to calculate the dynamic arcing process, and the arc parameters generated by opening the contacts in the circuit with a 5 A DC low current with a constant velocity were also obtained. It turned out that the computed time-varying contact voltage and arc duration agreed well with the test results. Thus, the validity of the simulation was demonstrated.

Break arcs are generated in a DC 42 V-10 A resistive circuit. The contact material is Ag or Ag/ZnO. The number of break operations is two hundreds for each contact material. The motion of break arcs is observed with a high-speed camera. Relationship between the dependence of arc duration on the number of operations and the motion of arc spots is investigated. The following results are shown. For Ag contacts the arc duration is almost constant independent to the number of break operations. For Ag/ZnO contacts, on the other hand, the arc duration changes irregularly to short (59 ms) or long (69 ms) arc-duration after 30th break operation. The moving range of arc spots on contact surfaces is broad for the case of short arc-duration and is narrow for the case of long arc-duration. The cause of the results for Ag/ZnO contacts is considered that the difference of the boiling points of Ag and ZnO leads to the porous structure on the contact surface.

Arc discharge generated by breaking electrical contact is considered as a main source of an undesired electromagnetic (EM) noise. To clarify mechanism of generation of the EM noise, feature extraction of bridge and short-time arc waveforms generated by slowly breaking Ag contact was discussed experimentally. The short-duration time arc before the ignition of the continuous metallic arc discharge was observed. The highest probability density voltage is defined as short-arc sustainable voltage (SASV). The relationship between SASV and duration of short-time arc was quantified experimentally. It is revealed that as the arc voltage of the short-time arc is higher, its duration becomes longer.

A novel two-dimensional discrete wavelet transform (2-DDWT) parallel architecture for higher throughput and lower energy consumption is proposed. The proposed architecture fully exploits full-page burst accesses of DRAM and minimizes the number of DRAM activate and precharge operations. Simulation results revealed that the architecture reduces the number of clock cycles for DRAM memory accesses as well as the DRAM power consumption with moderate cost of internal memory. Evaluation of the VLSI implementation of the architecture showed that the throughput of wavelet filtering was increased by parallelizing row filtering with a minimum area cost, thereby enabling DRAM full-page burst accesses to be exploited.

The gas-puffer effect has important effects on the interruption capability of a molded case circuit breaker (MCCB). In this paper, on the basis of a simplified model of an arc chamber with a single break, the effect of back-volume of an arc-quenching chamber on arc behavior in an MCCB is investigated. Firstly, using a 2-D optical-fiber arc-motion measurement system, experiments are performed to study the effect of back-volume on the arc-motion and gas pressure in an arc-quenching chamber. We demonstrate that the lower back-volume of the arc-quenching chamber is, the higher the pressure and the better the arc motion will be. Then, corresponding to the above experiments, the gas pressure inside the arc-quenching chamber is calculated using the integral conservation equation. The simulation results are consistent with the experimental results.

Motion of break arcs driven by external magnetic field is observed using a high-speed camera. The magnetic field is applied with a permanent magnet. Experimental circuit is DC42 V-10 A resistive circuit. Material of electrical contacts is silver. Following results are shown. The break arcs are driven in the direction according to Lorentz force. The arc duration decreases with decrease of the distance between the electrical contacts and the magnet. When the external magnetic-flux density at the position of the break arc is lower than a certain value, the effect of the magnetic field to drive the break arc becomes ineffective to shorten the arc duration. The result is explained with a relationship between the motion of break arc and the distribution of the external magnetic field.

The precision of magnetic field calculation is crucial to predict the arc behavior using magnetohydrodynamic (MHD) model. A integrated calculation method is proposed to couple the calculation of magnetic field and fluid dynamics based on the commercial software ANSYS and FLUENT, which especially benefits to take into account the existence of the ferromagnetic parts. An example concerning air arc is presented using the method.

The chaotic search is introduced into Quantum-behaved Particle Swarm Optimization (QPSO) to increase the diversity of the swarm in the latter period of the search, so as to help the system escape from local optima. Taking full advantages of the characteristics of ergodicity and randomicity of chaotic variables, the chaotic search is carried out in the neighborhoods of the particles which are trapped into local optima. The experimental results on test functions show that QPSO with chaotic search outperforms the Particle Swarm Optimization (PSO) and QPSO.

The intra-prediction unit is an essential part of H.264 codec, since it reduces the amount of data to be encoded by predicting pixel values (luminance and chrominance) from their neighboring blocks. A dedicated hardware implementation for the intra-prediction unit is required for real-time encoding and decoding of high resolution video data. To develop a cost-effective intra-prediction unit this paper proposes a novel architecture of intra-predictor generator, the core part of intra-prediction unit. The proposed intra-predictor generator enables the intra-prediction unit to achieve significant clock cycle reduction with approximately the same gate count, as compared to Huang's work [3].

In this letter, a mobile relay station (MRS) for vehicles with beamforming antennas is considered to increase the reliability of transmission link, especially for the MRS at cell boundary. Joint methods for cell searching and DoA estimation are proposed to form a beam in the direction of target BS while nulling interferences from adjacent BSs, especially for IP-based cellular systems employing break-before-make handover or make-before-break handover. The proposed cell searching and DoA estimation methods are evaluated by computer simulation under the environment of IEEE 802.16e (WiBro).

The concept of personal networks is very user-centric and representative for the next generation networks. However, the present security mechanism does not consider at all what happens whenever a mobile node (device) is compromised, lost or stolen. Of course, a compromised, lost or stolen mobile node (device) is a main factor to leak stored secrets. This kind of leakage of stored secrets remains a great danger in the field of communication security since it can lead to the complete breakdown of the intended security level. In order to solve this problem, we propose a 3-way Leakage-Resilient and Forward-Secure Authenticated Key Exchange (3LRFS-AKE) protocol and its security architecture suitable for personal networks. The 3LRFS-AKE protocol guarantees not only forward secrecy of the shared key between device and its server as well as providing a new additional layer of security against the leakage of stored secrets. The proposed security architecture includes two different types of communications: PN wide communication and communication between P-PANs of two different users. In addition, we give a performance evaluation and numerical results of the delay generated by the proposed security architecture.

Route optimization for network mobility is a key technique for providing a node in a mobile network (Mobile Network Node or MNN) with high quality broadband communications. Many schemes adding route optimization function to Network Mobility (NEMO) Basic Support protocol, the standardized network mobility management protocol from the IETF nemo working group, have already been proposed in recent years. One such scheme, a scheme using Hierarchical Mobile IPv6 (HMIPv6) aims to overcome micromobility management issues as well by applying a mechanism based on HMIPv6. The traditional scheme, however, suffers from a significant number of signaling messages as the number of MNNs and/or the number of their Correspondent Nodes (CNs) increase, because many messages notifying the MNNs' Home Agents (HAMNNs) and the CNs of the mobile network's movement are generated simultaneously each time the mobile network moves to the domain of another micromobility management router (Mobility Anchor Point or MAP). This paper proposes a scheme to overcome this problem. Our scheme reduces the number of signaling messages generated at the same time by managing the mobility of MNNs using multiple MAPs distributed within a network for load sharing. The results of simulation experiments show that our scheme works efficiently compared to the traditional scheme when a mobile network has many MNNs and/or these MNNs communicate with many CNs.

This work presents a novel scalable and systolic Montgomery's algorithm in GF(2m). The proposed algorithm is based on the Toeplitz matrix-vector representation, which obtains the scalable and systolic Montgomery multiplier in a flexible manner, and can adapt to the required precision. Analytical results indicate that the proposed multiplier over the generic field of GF(2m) has a latency of d+n(2n+1), where n = m / d , and d denotes the selected digital size. The latency is reduced to d+n(n+1) clock cycles when the field is constructed from generalized equally-spaced polynomials. Since the selected digital size is d ≥5 bits, the proposed architectures have lower time-space complexity than traditional digit-serial multipliers. Moreover, the proposed architectures have regularity, modularity and local interconnect ability, making them very suitable for VLSI implementation.

Failure avoidance capability is a desired feature for telecommunication networks, such as the Internet. However, not all failures can be promptly bypassed on the Internet because routing systems that are responsible for detecting and avoiding failures cannot detect all failures. Consequently, failures can interrupt internet communications for a long time, such as a few hours. This paper proposes a novel routing architecture called Drouting that enables flexible failure avoidance. In Drouting, routers calculate multipaths from a source to a destination by constructing Directed Acyclic Graphs (DAGs) that include all links in the intra-domain network graph. IP packets carry packet tags that are set by the end host. The packet tags are used to select a network path from the multipath routes. In this paper, the failure avoidance property of Drouting architecture is evaluated through comparison with another proposal, Deflection, using simulations. Simulations were performed on inferred and synthetic topologies. Drouting exhibits similar performance with Deflection in terms of the number of nexthops, the number of paths and the length of paths, while Drouting outperforms Deflection in the probability of success of failure avoidance.

Phased array antennas are attractive in terms of low cost and power consumption. This paper proposes a controlling scheme based on a bisection method for phased array antennas employing phase shifters with slow switching speed, which is typical for Micro Electro Mechanical Systems (MEMS) switches. Computer simulation results, assuming the IEEE 802.11a Wireless Local Area Network (WLAN) standard, show that the proposed scheme has good gain enhancement capability in multipath fading channels.

Similarity search in time-series databases finds such data sequences whose changing patterns are similar to that of a query sequence. For efficient processing, it normally employs a multi-dimensional index. In order to alleviate the well-known dimensionality curse, the previous methods for similarity search apply the Discrete Fourier Transform (DFT) to data sequences, and take only the first two or three DFT coefficients as organizing attributes. Other than this ad-hoc approach, there have been no research efforts on devising a systematic guideline for choosing the best organizing attributes. This paper first points out the problems occurring in the previous methods, and proposes a novel solution to construct optimal multi-dimensional indexes. The proposed method analyzes the characteristics of a target time-series database, and identifies the organizing attributes having the best discrimination power. It also determines the optimal number of organizing attributes for efficient similarity search by using a cost model. Through a series of experiments, we show that the proposed method outperforms the previous ones significantly.