In this paper, a contactless measurement technique of passive intermodulation (PIM) using a coaxial tube excited with standing waves is proposed. The principle of the proposed method is described using a two-port network model with the lumped resistances representing the losses of a specimen and test equipment. To show its validity, a test using nickel wires producing high PIM is carried out, and its PIM-dependency on DUT-position in the coaxial tube is simulated using the FDTD method. The simulated result shows a good agreement to the experiment. Through the examination, it is found that the power consumption by the PIM source in a specimen is essential in PIM production, and sensitive PIM detection does not require good matching condition. Finally, the relation between PIM-source size and generated PIM level is also examined. The result shows that at least 18 dB-PIM reduction is obtained by PIM source size in a half-wavelength conductive wire.

In this paper, a new skin detection method using pixel color and image regional information, intended for objectionable image filtering is proposed. The method consists of three stages: skin detection, feature extraction and image classification. Skin detection is implemented in two steps. First, a Sinc function, fitted to skin color distribution in the Cb-Cr chrominance plane is used for detecting pixels with skin color properties. Next, to benefit regional information, based on the theory of color image reproduction, it's shown that the scattering of skin pixels in the RGB color space can be approximated by an exponential function. This function is incorporated to extract the final accurate skin map of the image. As objectionable image features, new shape and direction features, along with area feature are extracted. Finally, a Multi-Layer Perceptron trained with the best set of input features is used for filtering images. Experimental results on a dataset of 1600 images illustrate that the regional method improves the pixel-based skin detection rate by 10%. The final classification result with 94.12% accuracy showed better results when compared to other methods.

Heterogeneous resources such as configurable logic blocks (CLBs), multiplier blocks (MULs) and RAM blocks (RAMs) where millions of logic gates are included have been added to field programmable gate arrays (FPGAs). The fixed-outline floorplanning used by the existing methods always has a big penalty item in the objective function to ensure all the modules are placed in the specified chip region, which maybe greatly degrade the wirelength. This paper presents a three-phase floorplanning method for heterogeneous FPGAs. First, a non-slicing free-outline floorplanning method is used to optimize the wirelength, however, in this phase, the satisfaction of resource requirements from functional modules might fail. Second, a min-cost-max-flow algorithm is used to tune the assignment of CLBs to functional modules, and assign contiguous regions to each module so that all the functional modules satisfy CLB requirements. Finally, the MULs and RAMs are allocated to modules by a network flow model. CLBs hold the maximum quantity among all the resources. Therefore, making a high utilization of them means an enhancement of the FPGA densities. The proposed method can improve the utilization of CLBs, hence, much larger circuits could be mapped to the same FPGA chip. The results show that about 7–85% wirelength reduction is obtained, and CLB utilization is improved by about 25%.

In this letter, we consider a control problem of a chain of integrators by output feedback under sensor noise. First, we introduce a measurement output feedback controller which drives all states and output of the considered system to arbitrarily small bounds. Then, we suggest a measurement output feedback controller coupled with a switching gain-scaling factor in order to improve the transient response and retain the same arbitrarily small ultimate bounds as well. An example is given to show the advantage of the proposed control method.

In this paper, the optimal control problem of a probabilistic Boolean network (PBN), which is one of the significant models in gene regulatory networks, is discussed. In the existing methods of optimal control for PBNs, it is necessary to compute state transition diagrams with 2n nodes for a given PBN with n states. To avoid this computation, a polynomial optimization approach is proposed. In the proposed method, a PBN is transformed into a polynomial system, and the optimal control problem is reduced to a polynomial optimization problem. Since state transition diagrams are not computed, the proposed method is convenient for users.

The optimal way to build speech understanding modules depends on the amount of training data available. When only a small amount of training data is available, effective allocation of the data is crucial to preventing overfitting of statistical methods. We have developed a method for allocating a limited amount of training data in accordance with the amount available. Our method exploits rule-based methods for when the amount of data is small, which are included in our speech understanding framework based on multiple model combinations, i.e., multiple automatic speech recognition (ASR) modules and multiple language understanding (LU) modules, and then allocates training data preferentially to the modules that dominate the overall performance of speech understanding. Experimental evaluation showed that our allocation method consistently outperforms baseline methods that use a single ASR module and a single LU module while the amount of training data increases.

Based on a reverse converter algorithm derived from the New Chinese Remainder Theorem I, an algorithm for sign detection of RNS {2n-1, 2n, 2n+1} is presented in this paper. The hardware of proposed algorithm can be implemented using two n-bit additions and one (n+1)-bit comparator. Comparing with the previous paper, the proposed algorithm has reduced the number of additions used in the circuit. The experimental results show that the proposed circuit achieves 17.3% savings in area for small moduli and 10.5% savings in area for large moduli on an average, with almost the same speed. The power dissipations obtain 12.6% savings in average.

There are many roles to play in the bug fixing process in open source software development. A developer called “Committer”, who has a permission to submit a patch into a software repository, plays a major role in this process and holds a key to the successfulness of the project. Despite the importance of committer's activities, we suspect that sometimes committers can make mistakes which have some consequences to the bug fixing process (e.g., reopened bugs after bug fixing). Our research focuses on studying the consequences of each committer's activities to this process. We collected each committer's historical data from the Eclipse-Platform's bug tracking system and version control system and evaluated their activities using bug status in the bug tracking system and commit log in the version control system. Then we looked deeper into each committer's characteristics to see the reasons why some committers tend to make mistakes more than the others.

This letter proposes a simple heuristic to identify the discrete-time switched autoregressive exogenous (SARX) systems. The goal of the identification is to identify the switching sequence and the system parameters of all submodels simultaneously. In this letter the SARX system identification problem is formulated as the l0 norm minimization problem, and an iterative algorithm is proposed by applying the reweighted least squares technique. Although the proposed algorithm is heuristic, the numerical examples show its efficiency and robustness for noise.

This paper presents a Microscopic Local Binary Pattern (MLBP) for texture classification. The conventional LBP methods which rely on the uniform patterns discard some texture information by merging the nonuniform patterns. MLBP preserves the information by classifying the nonuniform patterns using the structure similarity at microscopic level. First, the nonuniform patterns are classified into three groups using the macroscopic information. Second, the three groups are individually divided into several subgroups based on the microscopic structure information. The experiments show that MLBP achieves a better result compared with the other LBP related methods.

This letter discusses the applicability of boolean satisfiability (SAT) solving to pairwise testing in practice. Due to its recent rapid advance, using SAT solving seems a promising approach for search-based testing and indeed has already been practiced in test generation for pairwise testing. The previous approaches use SAT solving either for finding a small test set in the absence of parameter constraints or handling constraints, but not for both. This letter proposes an approach that uses a SAT solver for constructing a test set for pairwise testing in the presence of parameter constraints. This allows us to make full use of SAT solving for pairwise testing in practice.

A novel long-term sub-band entropy (LT-SubEntropy) measure, which uses improved long-term spectral analysis and sub-band entropy, is proposed for voice activity detection (VAD). Based on the measure, we can accurately exploit the inherent nature of the formant structure on speech spectrogram (the well-known as voiceprint). Results show that the proposed VAD is superior to existing standard VAD methods at low SNR levels, especially at variable-level noise.

The impact and benefits of infrastructure support are shown by introducing an achievable throughput scaling law of a ultra-wide band (UWB) ad hoc network in which m base stations (BSs) are regularly located. The existing multi-hop scheme consisting of two variants, with and without BS help, is utilized with a slight modification. Our result indicates that the derived throughput scaling depends on the path-loss exponent due to the power-limited characteristics for all operating regimes examined. Furthermore, it is shown that the total throughput scales linearly with parameter m as m is larger than a certain level. It thus turns out the use of infrastructure is also helpful in improving the throughput scaling of UWB networks in some conditions.

A folded monopole antenna fed by a CPW-to-trident transition feeder for compact wireless USB dongle devices is proposed. The antenna's dimensions are 1644.83.5 mm3, so it is suitable for low-profile wireless USB dongles. The proposed, compact monopole antenna resonates from 2.28 GHz to 10.8 GHz; hence, it can cover all wireless bands including WiBro (2.3–2.4 GHz), Bluetooth (2.4–2.484 GHz), WiMAX (2.5–2.7 GHz and 3.4–3.6 GHz), satellite DMB (2.605–2.655 GHz), 802.11b/g/a WLAN (2.4–2.485 GHz and 5.15–5.825 GHz), and UWB (3.1–10.6 GHz). A fabricated antenna is tested on a laptop to investigate the effects of the keypad and LCD screen on the resonant frequency and radiation pattern. The measured average gain of the fabricated antenna ranges from -2.76 dBi to 0.72 dBi.

IEEE 802.15.4 based devices are a key component for mobile and pervasive computing. However, their small dimensions and reduced resources, together with the intrinsic properties of wireless communication, make it difficult to evaluate such networked systems through real-world trials. In this paper we present an emulation testbed intended for the evaluation of IEEE 802.15.4 networked systems. The testbed builds on the generic framework of the wireless network testbed QOMB, and adds IEEE 802.15.4 network, processor and sensing emulation functionality. We validated the testbed through a series of experiments carried out both through real-world trials in a smart home environment, and through emulation experiments on our testbed. Our results show that one can accurately, and in real time, execute IEEE 802.15.4 network applications on our testbed in an emulated environment that reproduces closely the real scenario.

For real-time services, such as VoIP and videoconferencing supplied through a multi-domain MPLS network, it is vital to guarantee end-to-end QoS of the inter-domain paths. Thus, it is important to allocate an appropriate QoS class to the inter-domain paths in each transit domain. Because each domain has its own policy for QoS class allocation, each domain must then allocate an appropriate QoS class adaptively based on the estimation of the QoS class allocation policies adopted in other domains. This paper proposes an adaptive method for acquiring a QoS class allocation policy through the use of reinforcement learning. This method learns the appropriate policy through experience in the actual QoS class allocation process. Thus, the method can adapt to a complex environment where the arrival of inter-domain path requests does not follow a simple Poisson process and where the various QoS class allocation policies are adopted in other domains. The proposed method updates the allocation policy whenever a QoS class is actually allocated to an inter-domain path. Moreover, some of the allocation policies often utilized in the real operational environment can be updated and refined more frequently. For these reasons, the proposed method is designed to adapt rapidly to variances in the surrounding environment. Simulation results verify that the proposed method can quickly adapt to variations in the arrival process of inter-domain path requests and the QoS class allocation policies in other domains.

This study compares the performances of waveband protection and wavelength path protection in survivable hierarchical optical path networks. Network costs and the number of switching operations necessary are evaluated for different ratios of protected demand. Numerical results demonstrate that waveband protection can drastically decrease the number of switching operations in the case of failure, while both waveband and wavelength path protection effectively reduce the network resources needed compared to single layer optical path networks.

An ad hoc network is a decentralized network that consists of mobile nodes with wireless communication devices without the aid of access points. A Vehicular Ad-hoc NETwork (VANET) is one of the representative applications of the ad hoc network. Epidemic routing has been proposed as a routing protocol based on Store-Carry-Forward mechanism for VANET environment. However, in Epidemic Routing, network resources such as packet buffer of a node are significantly consumed because data packets are spread across the network. Therefore, this paper proposes a new autonomous clustering-based data transfer scheme using positions and moving direction of vehicles for VANETs. The autonomous clustering configures multiple clusters in the network and then only the cluster head that manages the cluster stores data packets. Whenever the cluster meets a new cluster, the cluster head of the cluster decides whether it should forward data packets to the new cluster based on its own position, the destination node's position, and moving direction of the cluster. Finally, this paper presents the simulation results to show the effectiveness of the proposed scheme.

We propose linear precoders which jointly minimize the mean-squared error of estimated symbol at the destination node for cooperative multiple-input multiple-output communication systems. Unlike the existing precoders which require high computational complexity to solve the optimization problem on the direct link, the proposed precoder is expressed in a closed-form. Simulation results show that the proposed precoder outperforms the existing precoders in the low SNR region. Moreover, we observe that the proposed iterative algorithm is not sensitive to the initial matrices.

This paper focuses on the latest research of switching arc both in vacuum and SF6 substitutes in our group. The crucial characteristics of vacuum arc are illustrated, including the motion and distribution of single cathode spot and multiple cathode spots, the influence of axial magnetic field on arc plasma characteristics, the influence of composite magnetic field on cathode jets, and the study of anode activities. Meanwhile, the arc characteristics in SF6 and its substitutes (Ar, CO2 and N2) at different pressures and gap distances are investigated by experiments and simulation.