For realizing wideband class-F power amplifiers (PA), geo-electrical analysis methods are introduced to determine the best design parameters in a simpler way than relying on computer-guided optimization. The fabricated class-F PA at 1.9 GHz demonstrated a peak efficiency of 80.5% and a bandwidth of 750 MHz for an efficiency of more than 63%. It is presumed that the optimization increased the bandwidth by 10%.
Peng CHENG Chun-Wei LIN Jeng-Shyang PAN Ivan LEE
Sharing data might bring the risk of disclosing the sensitive knowledge in it. Usually, the data owner may choose to sanitize data by modifying some items in it to hide sensitive knowledge prior to sharing. This paper focuses on protecting sensitive knowledge in the form of frequent itemsets by data sanitization. The sanitization process may result in side effects, i.e., the data distortion and the damage to the non-sensitive frequent itemsets. How to minimize these side effects is a challenging problem faced by the research community. Actually, there is a trade-off when trying to minimize both side effects simultaneously. In view of this, we propose a data sanitization method based on evolutionary multi-objective optimization (EMO). This method can hide specified sensitive itemsets completely while minimizing the accompanying side effects. Experiments on real datasets show that the proposed approach is very effective in performing the hiding task with fewer damage to the original data and non-sensitive knowledge.
In this paper we consider two non-parametric estimation methods for software reliability assessment without specifying the fault-detection time distribution, where the underlying stochastic process to describe software fault-counts in the system testing is given by a non-homogeneous Poisson process. The resulting data-driven methodologies can give the useful probabilistic information on the software reliability assessment under the incomplete knowledge on fault-detection time distribution. Throughout examples with real software fault data, it is shown that the proposed methods provide more accurate estimation results than the common parametric approach.
Xue LEI Wei HUANG Wenqing FAN Yixian YANG
Dynamic analysis is frail and insufficient to find hidden paths in environment-intensive program. By analyzing a broad spectrum of different concolic testing systems, we conclude that a number of them cannot handle programs that interact with the environment or require a complete working model. This paper addresses this problem by automatically identifying and modifying outputs of the data input interface function(DIIF). The approach is based on fine-grained taint analysis for detecting and updating the data that interacts with the environment to generate a new set of inputs to execute hidden paths. Moreover, we developed a prototype and conducted extensive experiments using a set of complex and environmentally intensive programs. Finally, the result demonstrates that our approach could identify the DIIF precisely and discover hidden path obviously.
In this letter we develop a software reliability modeling framework by introducing the Burr XII distributions to software fault-detection time. An extension to deal with software metrics data characterizing the product size, program complexity or testing expenditure is also proposed. Finally, we investigate the goodness-of-fit performance and compare our new models with the existing ones through real data analyses.
Tomomi YOSHIMOTO Yoshiaki SUGIMOTO Tatsuo IWATA
The effect of annealing on the field emission characteristics of a field emitter comprising diamond micropowder was investigated. The threshold voltage Vth at which the emission current begins to flow decreased as the annealing temperature increased, and a minimum Vth was obtained at an annealing temperature of 1345K. The reduction in threshold voltage was due to a reduction in the work function with annealing.
Integral image is the sum of input image pixel values. It is mainly used to speed up the process of a box filter operation, such as Haar-like features. However, large memory capacity for integral image data can be an obstacle in an embedded environment with limited hardware. In a previous research, [5] reduced the size of integral image memory using 2×2 block structure with additional calculations. It can be easily extended to n×n block structure for further reduction, but it requires more additional calculations. In this paper, we propose a new block structure for the integral image by modifying the location of the reference pixel in the block. It results in much less additional calculations by reducing the number of memory accesses, while keeping the same amount of memory as the original block structure.
Zhong ZHANG Shuang LIU Zhiwei ZHANG
Sparsity-based methods have been recently applied to abnormal event detection and have achieved impressive results. However, most such methods suffer from the problem of dimensionality curse; furthermore, they also take no consideration of the relationship among coefficient vectors. In this paper, we propose a novel method called consistent sparse representation (CSR) to overcome the drawbacks. We first reconstruct each feature in the space spanned by the clustering centers of training features so as to reduce the dimensionality of features and preserve the neighboring structure. Then, the consistent regularization is added to the sparse representation model, which explicitly considers the relationship of coefficient vectors. Our method is verified on two challenging databases (UCSD Ped1 database and Subway batabase), and the experimental results demonstrate that our method obtains better results than previous methods in abnormal event detection.
A low loss intelligent power module (IPM) that specifically designed for high performance frequency-alterable air conditioner applications is proposed. This IPM utilizes 600 V trench gate field stop insulated gate bipolar transistors (TFS-IGBTs) as the main switching devices to deliver extremely low conduction and switching losses. In addition, 600 V SiC schottky barrier diodes (SBDs) are employed as the freewheeling diodes. Compared to conventional silicon fast recovery diodes (FRDs) SiC SBDs exhibit practically no reverse recovery loss, hence can further reduce the power loss of the IPM. Experimental results reveal that the power loss of the proposed IPM is between 3.5∼21.7 W at different compressor frequencies from 10 to 70 Hz, which achieving up to 12.5%∼25.5% improvement when compared to the state-of-the-art conventional Si-based IGBT IPM.
Chao-Li MENG Shiaw-Wu CHEN Ann-Chen CHANG
This letter deals with direction-of-arrival (DOA) estimate problem based on gravitational search algorithm (GSA) with multiple signal classification (MUSIC) criterion for code-division multiple access (CDMA) signals. It has been shown that the estimate accuracy of the searching-based MUSIC estimator strictly depends on the number of search grids used during the search process, which is time consuming and the required number of search grids is not clear to determine. In conjunction with the GSA-based optimization, the high resolution DOA estimation can be obtained; meanwhile the searching grid size is no need to know previously. In this letter, we firstly present a GSA-based DOA estimator with MUSIC criterion under high interferer-to-noise ratio circumstances. Second, for the purpose to increase the estimation accuracy, we also propose an improved GSA with adaptive multiple accelerations, which depend on Newton-Raphson method. Several computer simulations are provided for illustration and comparison.
In this letter, we present a meet-in-the-middle attack on the 5-round reduced Kuznyechik cipher which has been recently chosen to be standardized by the Russian federation. Our attack is based on the differential enumeration approach. However, the application of the exact approach is not successful on Kuznyechik due to its optimal round diffusion properties. Accordingly, we adopt an equivalent representation for the last round where we can efficiently filter ciphertext pairs and launch the attack in the chosen ciphertext setting. We also utilize partial sequence matching which further reduces the memory and time complexities. For the 5-round reduced cipher, the 256-bit master key is recovered with an online time complexity of 2140.3, a memory complexity of 2153.3, and a data complexity of 2113.
Eun Jung JANG Jaeyong CHUNG Jacob A. ABRAHAM
With aggressive device scaling, timing failures have become more prevalent due to manufacturing defects and process variations. When timing failure occurs, it is important to take corrective actions immediately. Therefore, an efficient and fast diagnosis method is essential. In this paper, we propose a new diagnostic method using timing information. Our method approximately estimates all the segment delays of measured paths in a design, using inequality-constrained least squares methods. Then, the proposed method ranks the possible locations of delay defects based on the difference between estimated segment delays and the expected values of segment delays. The method works well for multiple delay defects as well as single delay defects. Experiment results show that our method yields good diagnostic resolution. With the proposed method, the average first hit rank (FHR), was within 7 for single delay defect and within 8 for multiple delay defects.
Li BIN Deng ZHUN Xie LIANG Xiangliang JIN
A high energy-efficiency and area-reduction switching scheme for a low-power successive approximation register (SAR) analog-to-digital converter (ADC) is presented. Based on the sequence initialization, monotonic capacitor switching procedure and multiple reference voltages, the average switching energy and total capacitance of the proposed scheme are reduced by 99.4% and 87.5% respectively, compared to the conventional architecture.
Atsuki NAGAO Kazuhisa SETO Junichi TERUYAMA
We propose efficient algorithms for Sorting k-Sets in Bins. The Sorting k-Sets in Bins problem can be described as follows. We are given numbered n bins with k balls in each bin. Balls in the i-th bin are numbered n-i+1. We can only swap balls between adjacent bins. Our task is to move all of the balls to the same numbered bins. For this problem, we give an efficient greedy algorithm with $rac{k+1}{4}n^2+O(k+n)$ swaps and provide a detailed analysis for k=3. In addition, we give a more efficient recursive algorithm using $rac{15}{16}n^2+O(n)$ swaps for k=3.
Kugjin YUN Won-sik CHEONG Kyuheon KIM
Recently, standard organizations of ATSC, DVB and TTA have been working to design various immersive media broadcasting services such as the hybrid network-based 3D video, UHD video and multiple views. This letter focuses on providing a new synchronization and transport system target decoder (T-STD) model of 3D video distribution based on heterogeneous transmission protocol in a hybrid network environment, where a broadcasting network and broadband (IP) network are combined. On the basis of the experimental results, the proposed technology has been proved to be successfully used as a core element for synchronization and T-STD model in a hybrid network-based 3D broadcasting. It has been also found out that it could be used as a base technique for various IP associated hybrid broadcasting services.
Yingxu LAI Wenwen ZHANG Zhen YANG
Current software behavior models lack the ability to conduct semantic analysis. We propose a new model to detect abnormal behaviors based on a function semantic tree. First, a software behavior model in terms of state graph and software function is developed. Next, anomaly detection based on the model is conducted in two main steps: calculating deviation density of suspicious behaviors by comparison with state graph and detecting function sequence by function semantic rules. Deviation density can well detect control flow attacks by a deviation factor and a period division. In addition, with the help of semantic analysis, function semantic rules can accurately detect application layer attacks that fail in traditional approaches. Finally, a case study of RSS software illustrates how our approach works. Case study and a contrast experiment have shown that our model has strong expressivity and detection ability, which outperforms traditional behavior models.
Naoki OKUDA Nobuyuki TAMURA Tetsushi YUGE Shigeru YANAGI
In this paper, we study on an availability analysis for a multibase system with lateral resupply of spare items between bases. We construct a basic model that a spare item of a base is transported for operation to another base without spare upon occurrence of failure, and simultaneously, the base that supplies the spare item receives the failed item of the other base for repair. We propose an approximation method to obtain the availability of the system and show the accuracy of the solution through numerical experiments. Also, two modified models are constructed to show the efficiency of the basic model. The two models modify the assumption on the lateral resupply of spare items between bases in the basic model. We numerically illustrate that the basic model can increase the availability of the system compared with the two modified models through Monte Carlo simulation.
Huifa LIN Koji ISHIBASHI Won-Yong SHIN Takeo FUJII
In this paper, we introduce a distributed power allocation strategy for random access, that has the capabilities of multipacket reception (MPR) and successive interference cancellation (SIC). The proposed random access scheme is suitable for machine-to-machine (M2M) communication application in fifth-generation (5G) cellular networks. A previous study optimized the probability distribution for discrete transmission power levels, with implicit limitations on the successful decoding of at most two packets from a single collision. We formulate the optimization problem for the general case, where a base station can decode multiple packets from a single collision, and this depends only on the signal-to-interference-plus-noise ratio (SINR). We also propose a feasible suboptimal iterative per-level optimization process; we do this by introducing relationships among the different discrete power levels. Compared with the conventional power allocation scheme with MPR and SIC, our method significantly improves the system throughput; this is confirmed by computer simulations.
Hideo FUJIWARA Katsuya FUJIWARA
In our previous work [12], [13], we introduced generalized feed-forward shift registers (GF2SR, for short) to apply them to secure and testable scan design, where we considered the security problem from the viewpoint of the complexity of identifying the structure of GF2SRs. Although the proposed scan design is secure in the sense that the structure of a GF2SR cannot be identified only from the primary input/output relation, it may not be secure if part of the contents of the circuit leak out. In this paper, we introduce a more secure concept called strong security such that no internal state of strongly secure circuits leaks out, and present how to design such strongly secure GF2SRs.
In this letter, a new subband adaptive filter (SAF) which is robust against impulsive noise in system identification is presented. To address the vulnerability of adaptive filters based on the L2-norm optimization criterion to impulsive noise, the robust SAF (R-SAF) comes from the L1-norm optimization criterion with a constraint on the energy of the weight update. Minimizing L1-norm of the a posteriori error in each subband with a constraint on minimum disturbance gives rise to robustness against impulsive noise and the capable convergence performance. Simulation results clearly demonstrate that the proposal, R-SAF, outperforms the classical adaptive filtering algorithms when impulsive noise as well as background noise exist.