As a promising lamination-loss-free fabrication technique, diffusion bonding of etched thin metal plates is used to realize double-layer waveguide slot antennas. Alternating-phase feed is adopted in this paper to reduce the number of laminated plates to simplify fabrication as well as to reduce cost. A 20 × 20-element double-layer waveguide slot antenna with a bottom partially-corporate feed circuit is designed for 39GHz band operation as an example. The adjacent radiating waveguides as well as the 2 × 2 sub-arrays fed in an alternating-phase manner eliminate the need for complete electrical contact in the top layer. However, the feed circuit in the bottom layer has to be completely diffusion-bonded. These two layers are simply assembled by screws. An antenna laminated by only diffusion bonding is also fabricated and evaluated for comparison. The comparison proved that the simply fabricated antenna is comparable in performance to the fully diffusion-bonded one.

One of the procedures for increasing the number of multi-input and multi-output (MIMO) branches without increasing the computational cost for MIMO detection or multiplexing is to exploit parallel transmissions by using polarization multiplexing. In this paper the effectiveness of using polarization multiplexing is confirmed under the existence of polarization rotation, which is inevitably present in short-range multi-input and multi-output (SR-MIMO) channels with planar array antennas. It is confirmed that 8×8 SR-MIMO transmission system with polarization multiplexing has 60bit/s/Hz of channel capacity. This paper also shows a model for theoretical cross polarization discrimination (XPD) degradation, which is useful to calculate XPD degradations on diagonal paths.

Outsourcing to a cloud storage brings forth new challenges for the efficient utilization of computing resources as well as simultaneously maintaining privacy and security for the outsourced data. Data deduplication refers to a technique that eliminates redundant data on the storage and the network, and is considered to be one of the most-promising technologies that offers efficient resource utilization in the cloud computing. In terms of data security, however, deduplication obstructs applying encryption on the outsourced data and even causes a side channel through which information can be leaked. Achieving both efficient resource utilization and data security still remains open. This paper addresses this challenging issue and proposes a novel solution that enables data deduplication while also providing the required data security and privacy. We achieve this goal by constructing and utilizing equality predicate encryption schemes which allow to know only equivalence relations between encrypted data. We also utilize a hybrid approach for data deduplication to prevent information leakage due to the side channel. The performance and security analyses indicate that the proposed scheme is efficient to securely manage the outsourced data in the cloud computing.

This paper presents sufficient conditions for the existence of a common quadratic Lyapunov functions for two classes of switched linear systems which possess negative row strictly diagonally dominant and diagonalizable stable state matrices, respectively. Numerical examples will be given to verify the correctness of the proposed theorems.

Many discrete functions are often compactly represented by Decision Diagrams (DD). The main problem in the construction of decision diagrams is the space and time requirements. While constructing a decision diagram the memory requirement may grow exponentially with the function. Also, large numbers of temporary nodes are created while constructing the decision diagram for a function. Here the problem of reducing the number of temporary nodes is addressed with respect to the PLA specification format of a function, where the function is represented using a set of cubes. Usually a DD is constructed by recursively processing the input cubes in the PLA specification. The DD, representing a sub function, is specified by a single cube. This DD is merged with a master DD, which represents the entire previously processed cubes. Thus the master DD is constructed recursively, until all the cubes in the input cube set are processed. In this paper, an efficient method is proposed, which reorders and also partitions the cube set into unequal number of cubes per subset, in such a way that, the number of temporary nodes created and the number of logical operations done, during the merging of cubes with the master DD are reduced. This results in the reduction of space and time required for the construction of DDs to a remarkable extent.

Scalable Video Coding (SVC) is an extension of H.264/AVC, aiming to provide the ability to adapt to heterogeneous networks or requirements. It offers great flexibility for bitstream adaptation in multi-point applications such as videoconferencing. However, transcoding between SVC and AVC is necessary due to the existence of legacy AVC-based systems. The straightforward re-encoding method requires great computational cost, and delay-sensitive applications like videoconferencing require much faster transcoding scheme. This paper proposes a 3-stage fast SVC-to-AVC transcoder with medium-grain quality scalability (MGS) for videoconferencing applications. Hierarchical-P structured SVC bitstream is transcoded into IPPP structured AVC bitstream with multiple reference frames. In the first stage, mode decision is accelerated by proposed SVC-to-AVC mode mapping scheme. In the second stage, INTER motion estimation is accelerated by an optimized motion vector (MV) conjunction method to predict the MV with a reduced search range. In the last stage, hadamard-based all zero block (AZB) detection is utilized for early termination. Simulation results show that proposed transcoder achieves very similar coding efficiency to the optimal result, but with averagely 89.6% computational time saving.

A stochastic hybrid system can express complex dynamical systems such as biological systems and communication networks, but computation for analysis and control is frequently difficult. In this paper, for a class of stochastic hybrid systems, a discrete abstraction method in which a given system is transformed into a finite-state system is proposed based on the notion of bounded bisimulation. In the existing discrete abstraction method based on bisimulation, a computational procedure is not in general terminated. In the proposed method, only the behavior for the finite time interval is expressed as a finite-state system, and termination is guaranteed. Furthermore, analysis of genetic toggle switches is also discussed as an application.

This study presents efficient algorithms for performing multiply-by-3 (3N) and divide-by-3 (N/3) operations with the additions and subtractions, respectively. No multiplications and divisions are needed. Full adder (FA) and full subtractor (FS) can be implemented to realize the N3 and N/3 operations, respectively. For fast hardware implementation, this paper introduces two basic cells UCA and UCS for 3N and N/3 operations, respectively. For 3N operation, the UCA-based ripple carry adder (RCA) and carry lookahead adder (CLA) designs are proposed and their speed performances are estimated based on the delay data of standard cell library in TSMC 0.18µm CMOS process. Results show that the 16-bit UCA-based RCA is about 3 times faster than the conventional FA-based RCA and even 25% faster than the FA-based CLA. The proposed 16-bit and 64-bit UCA-based CLAs are 62% and 36% faster than the conventional FA-based CLAs, respectively. For N/3 operations, ripple borrow subtractor (RBS) is also presented. The 16-bit UCS-based RBS is about 15.5% faster than the 16-bit FS-based RBS.

Many controllers are implemented on digital platforms as periodic control tasks. But, in embedded systems, an amount of resources are limited and the reduction of resource utilization of the control task is an important issue. Recently, much attention has been paid to a self-triggered controller, which updates control inputs aperiodically. A control task by which the self-triggered controller is implemented skips the release of jobs if the degradation of control performances by the skipping can be allowed. Each job computes not only the updated control inputs but also the next update instant and the control task is in the sleep state until the instant. Thus the resource utilization is reduced. In this paper, we consider self-triggered predictive control (stPC) of mixed logical dynamical (MLD) systems. We introduce a binary variable which determines whether the control inputs are updated or not. Then, we formulate an stPC problem of mixed logical dynamical systems, where activation costs are time-dependent to represent the preference of activations of the control task. Both the control inputs and the next update instant are computed by solving a mixed integer programming problem. The proposed stPC can reduce the number of updates with guaranteeing stability of the controlled system.

Well designed redundant via-aware standard cells (SCs) can increase the redundant via1 insertion rate in cell-based designs. However, in conventional methods, manual- and visual-based checks are required to locate pins and tune the geometries of layouts. These tasks can be very time consuming and unreliable. In this work, an O(Nlog N) redundant via-aware standard cell optimization scheme is developed. The proposed method is an efficient layout check and optimization scheme that considers various redundant via configurations including the double-via and rectangle-via to shorten the design time for standard cells. The optimized SCs effectively increase the redundant via insertion rate, and in particular the insertion rate of via1 for both concurrent routing and post-layout optimization. Furthermore, an automatic layout checker and optimizer are more efficient in identifying expandable metal 1 pins in libraries that contain numerous cells than are conventional visual check and manual optimization. Therefore, the proposed scheme not only solves the problem of a low via1 insertion rate in nanometer regimes, but also provides an efficient layout optimizer for designing standard cells. Experimental results indicate that the optimized standard cells increase the double-via1 insertion rates by 21.9%.

This letter describes a design methodology for an arithmetic logic unit (ALU) incorporating reconfigurability based on double-gate carbon nanotube field-effect transistors (DG-CNTFETs). The design of a DG-CNTFET with an ambipolar-property-based reconfigurable static logic circuit is simple and straightforward using an ambipolar binary decision diagram (Am-BDD), which represents the cornerstone for the automatic pass transistor logic (PTL) synthesis flows of ambipolar devices. In this work, an ALU with 16 functions is synthesized by the design methodology of a DG-CNTFET-based reconfigurable static logic circuit. Furthermore, it is shown that the proposed ALU is much more flexible and practical than a conventional DG-CNTFET-based reconfigurable ALU.

Some key challenges remain to be overcome before spectrum sensing can be widely used to identify spectrum opportunities in the TV bands. To fulfill the strict sensing requirement specified by FCC, a comprehensive sensing algorithm, which produces high SNR gain and maintains sensing robustness under complex noise conditions, needs to be implemented. In addition, carefully designed physical features and improvement on cost performance ratio are also essential if a prototype is to be commercialized. To the best of our knowledge, no success has ever been announced in developing a sensing prototype that fulfills both FCC sensing requirement and the above mentioned features. In this paper, we introduce a recently developed sensing prototype for Japanese digital TV signals of ISDB-T. The prototype operates in the Japanese UHF TV band of 470-770MHz and can reliably identify presence/absence of an ISDB-T signal at the level of -114dBm in a 6MHz channel. Moreover, it has constrained size and weight, and is capable of accurately measuring power of an ISDB-T signal at an extremely low level. Efforts on reducing cost have also been made by avoiding the use of electronic components/devices of high price. Both laboratory and field tests are performed to evaluate its sensing performance and power measurement capability. In the laboratory test, sensing performance under conditions of adjacent channel interference and frequency offset, and power measurement accuracy, are checked. In field tests, the prototype is attached in a vehicle and is checked for its capability to identify the presence of purposely broadcasted ISDB-T signals at some fixed locations and also during movement of the vehicle.

In this paper, we focus on a centralized spectrum access strategy in a cognitive radio network, in which a single licensed spectrum with one primary user (PU) and several secondary users (SUs) (multiple input streams) are considered. We assume the spectrum can be divided into multiple channels and the packets from variable SUs can arrive at the system simultaneously. Taking into account the priority of the PU, we suppose that one PU packet can occupy the whole licensed spectrum, while one SU packet will occupy only one of the channels split from the licensed spectrum when that channel is not used. Moreover, in order to reduce the blocking ratio of the SUs, a buffer with finite capacity for the SUs is set. Regarding the packet arrivals from different SUs as multiple input streams, we build a two-dimensional Markov chain model based on the phase of the licensed spectrum and the number of SU packets in the buffer. Then we give the transition probability matrix for the Markov chain. Additionally, we analyze the system model in steady state and derive some important performance measures for the SUs, such as the average queue length in the buffer, the throughput and the blocking ratio. With the trade-off between different performance measures, we construct a net benefit function. At last, we provide numerical results to show the change trends of the performance measures with respect to the capacity of the SU buffer under different network conditions, and optimize the capacity of the SU buffer accordingly.

In this work, a measurement-based procedure aimed at deriving a behavioral model of Bulk Current Injection (BCI) probes clamped onto multi-wire cable bundles is proposed. The procedure utilizes the measurement data obtained by mounting the probe onto the calibration jig for model-parameters extraction, and 2D electromagnetic simulations to adapt such parameters to the specific characteristics of the cable bundle under analysis. Outcome of the analysis is a behavioral model which can be easily implemented into the SPICE environment. Without loss of generality, the proposed model is here used to predict the radio-frequency noise stressing the terminal units of a two-wire harness. Model accuracy in predicting the common and differential mode voltages induced by BCI at the line terminals is assessed by EM modeling and simulation of the involved injection setup by the commercial software CST Microwave Studio.

Much work in cooperative communication has been done from the perspective of the physical and network layers. However, the exact impact of signal error rate performance on cooperative routing discovery still remains unclear in multihop ad hoc networks. In this paper, we show the symbol error rate (SER) performance improvement obtained from cooperative commutation, and examine how to incorporate the factor of SER into the distributed routing discovery scheme called DGCR (Dynamic Geographic Cooperative Routing). For a single cooperative communication hop, we present two types of metric to specify the degree that one node is suitable for becoming the relay node. One metric is the potential of a node to relay with optimal SER performance. The other metric is the distance of a node to the straight line that passes through the last forwarding node and the destination. Based on location knowledge and contention scheme, we combine the two metrics into a composite metric to choose the relay node. The forwarding node is chosen dynamically according to the positions of the actual relay node and the destination. Simulation results show that our approach outperforms non-cooperative geographic routing significantly in terms of symbol error rate, and that DGCR's SER performance is better than traditional geographic cooperative routing with slight path length increase.

Formalizing requirements in formal specifications is an effective way to deepen the understanding of the envisioned system and reduce ambiguities in the original requirements. However, it requires mathematical sophistication and considerable experience in using formal notations, which remains a challenge to many practitioners. To handle this challenge, this paper describes a pattern-based approach to facilitate the formalization of requirements. In this approach, a pattern system is pre-defined to guide requirements formalization where each pattern provides a specific solution for formalizing one kind of function into a formal expression. All of the patterns are classified and organized into a hierarchical structure according to the functions they can be used to formalize. The distinct characteristic of our approach is that all of the patterns are stored on computer as knowledge for creating effective guidance to facilitate the developer in requirements formalization; they are “understood” only by the computer but transparent to the developer. We also describe a prototype tool that supports the approach. It adopts Hierarchical Finite State Machine (HFSM) to represent the pattern knowledge and implements an algorithm for applying it to assist requirements formalization. Two experiments on the tool are presented to demonstrate the effectiveness of the approach.

Web page segmentation has a variety of benefits and potential web applications. Early techniques of web page segmentation are mainly based on machine learning algorithms and rule-based heuristics, which cannot be used for large-scale page segmentation. In this paper, we propose a formulated page segmentation method using visual semantics. Instead of analyzing the visual cues of web pages, this method utilizes three measures to formulate the visual semantics: layout tree is used to recognize the visual similar blocks; seam degree is used to describe how neatly the blocks are arranged; content similarity is used to describe the content coherent degree between blocks. A comparison experiment was done using the VIPS algorithm as a baseline. Experiment results show that the proposed method can divide a Web page into appropriate semantic segments.

This paper describes a novel method for the bi-directional transformation between the power consumption patterns of appliances and human living activities. We have been proposing a demand-side energy management system that aims to cut down the peak power consumption and save the electric energy in a household while keeping user's quality of life based on the plan of electricity use and the dynamic priorities of the appliances. The plan of electricity use could be established in advance by predicting appliance power consumption. Regarding the priority of each appliance, it changes according to user's daily living activities, such as cooking, bathing, or entertainment. To evaluate real-time appliance priorities, real-time living activity estimation is needed. In this paper, we address the problem of the bi-directional transformation between personal living activities and power consumption patterns of appliances. We assume that personal living activities and appliance power consumption patterns are related via the following two elements: personal appliance usage patterns, and the location of people. We first propose a Living Activity - Power Consumption Model as a generative model to represent the relationship between living activities and appliance power consumption patterns, via the two elements. We then propose a method for the bidirectional transformation between living activities and appliance power consumption patterns on the model, including the estimation of personal living activities from measured appliance power consumption patterns, and the generation of appliance power consumption patterns from given living activities. Experiments conducted on real daily life demonstrate that our method can estimate living activities that are almost consistent with the real ones. We also confirm through case study that our method is applicable for simulating appliance power consumption patterns. Our contributions in this paper would be effective in saving electric energy, and may be applied to remotely monitor the daily living of older people.

In this letter, advanced QRD-M detection using iterative scheme is proposed. This scheme has a higher diversity degree than conventional QRD-M detection. According to the simulation results, the performance of proposed QRD-M detection is 0.5dB to 5.5dB better than the performance of conventional QRD-M detection and average iteration time is approximately 1 in the value of M = 1, 2, 3. Therefore, the proposed QRD-M detection has better performance than conventional QRD-M detection, particularly in a high SNR environment and low modulation order.

This letter proposes an efficient compression scheme for the copyright- and privacy-protected image trading system. The proposed scheme multiplies pseudo random signs to amplitude components of discrete cosine transformed coefficients before the inverse transformation is applied. The proposed scheme efficiently compresses amplitude-only image which is the inversely transformed amplitude components, and the scheme simultaneously improves the compression efficiency of phase-only image which is the inversely transformed phase components, in comparison with the conventional systems.