Hierarchical Optimization of Multi-objective Embedded System Design Using Pareto-frontier Algebra

This paper presents a novel scheme of hier-archical design space exploration, aiming at multi-objective embedded system design. Multi-objective hierarchical design methodology is prospective to deal with the design of modern complex embedded systems. However, the impact of decision data piling up across hierarchy boundaries as occurred in the previous works has made this method inefficient and restricted. This paper employs Pareto-optimal theory to analyze the hierarchical design space, and indicates how intermediate solutions of lower levels contribute to the final optimal solutions. By these indications, the paper adopts a multi-level treelike optimization procedure, and has proved that, under the independence conditions, optimization in each hierarchical level can be performed independently. Further more, the frameworks of uncon- strained and constrained hierarchical optimization systems have been provided and proved. This is the very first time to formally explore the design space of multi-objective hierarchicai system, which contributes to the promotion of novel hierarchical partitioning and synthesizing methodology.     

A Novel Architecture of Special Arithmetic Function Unit for Area-Efficient Programmable Vertex Shader

A novel architecture of high precision, floating-point special Arithmetic function unit （SFU） for elementary transcendental functions is presented in this paper to provide area efficiency as well as high performance for programmable vertex shader. From the architecture point of view, the evaluation of quadratic approximation for special functions is performed by sharing the SIMD vector unit in shader architecture to minimize processing latency and to reduce area cost in SFU. An optimized minimax approach is proposed as well to obtain the finite-length and normalized quadratic coefficients for high precision. The experiment result shows that the proposed SFU can significantly reduce area cost and by adopting the proposed SFU, a vertex shader with Transport triggered architecture （TTA） can achieve 15.0% improvement on average in performance/area ratio for various shading benchmarks.     

A Population-Membrane-System-Inspired Evolutionary Algorithm for Distribution Network Reconfiguration

This paper proposes a Population- membrane-system-inspired evolutionary algorithm （PM- SIEA）, which is designed by using a population P system and a Quantum-inspired evolutionary algorithm （QIEA）. PMSIEA uses the population P system with three cells to organize three variants of QIEAs, where communications between cells are performed at the level of genes, instead of the level of individuals reported in the existing membrane algorithms. This work provides a useful framework for synthesizing different algorithms at macro level and exchanging genic information at micro scale. Experimental results conduced on knapsack problems show that PMSIEA is superior to four representative QIEAs and our previous work with respect to the quality of solutions and the elapsed time. We also use PMSIEA to solve the optimal distribution system reconfiguration problem in power systems for minimizing the power loss.     

Necessary and Sufficient Stability Criterion and New Forbidden Region for Load Impedance Specification

A necessary and sufficient impedance stability criterion for the DC Distributed power system （DPS） is proposed in small-signal sense, which has no conservativeness when compared with other stability criteria. This paper discusses the stability margin and gives it a definition for the round forbidden region. The reasons why the stability margin varies at different interfaces are also discussed in this paper. With the impedance stability criterion and stability margins considered, the sector forbidden region, which is a new forbidden region and can be easily calculated in the Bode diagram, is proposed to solve the calculation problem of the round forbidden region in engineering application. This paper also provides examples and simulations to verify the necessary and sufficient impedance stability criterion and the proposed sector forbidden region for the load impedance specification.     

Perceptual Quality Assessment of SAR Image Compression Based on Image Content Partition and Neural Network

Image quality assessment （IQA） is of fundamental importance for image compression applications. Traditional IQA measures used for Synthetic aperture radar （SAR） image compression do not consider the properties of Human visual system （HVS）. Since human beings are the final users in most SAR image applications, the objective evaluation coordinate to human＇s perception is the most acceptable and practical IQA method. In this paper, we propose a novel objective approach based on image content partition and Neural network （NN） by introducing the HVS and SAR image characteristics. Experimental results demonstrate that the proposed metric correlates well with subjective quality of SAR image compression and outperforms those state-of-art objective models using Structural similarity index （SSIM）, Singular value decomposition （SVD） and Visual information fidelity （VIF）.     

Model and Simulation of Multipath Error in DLL for GPS Receiver

Although different multipath error models of Delay lock loop （DLL） used in GPS receiver are established, they have never been put together for comparison. Furthermore, no universal simulation method is developed to get a fair comparison among these models. A new model with implicate expression is hence proposed for the coherent DLL and the noncoherent Dot-product （DOT） power mode DLL. Meanwhile, a new simulation method based on the anonymous function in Matlab, which is especially suitable for models with implicit expressions is also proposed to compare the new model with the existing ones. The theoretical analysis and simulation results show that the existing models are the special case of the proposed one. The new simulation method can be used for the comparison of different multipath error models and the multipath error analysis of other DLLs for which only the implicit model is available.     

State Estimation for Linear Constrained Systems with Unknown Input

This paper deals with the filtering problem for linear discrete constrained dynamic systems with unknown input. The constraint matrix and constraint vector in this system are allowed to vary in the value and in the dimension. The original full state is separated into two parts, and the estimate of the state is reduced to find the optimal estimate of a singular system. The estimable condition is researched and a recursive estimator for the original full state is presented. A rigorous mathematical induction is given to compare the performance of our approach to that of the existing method without constraint. A numerical example is presented to demonstrate the effectiveness of the new method.     

Weak GPS Signal Acquisition Method Using Variable Threshold

Coherent integration and non-coherent ac- cumulation have been developed to acquire weak Global position system （GPS） signals. The threshold of acquisi- tion algorithm is fixed, and is determined by the weak- est signal. Strong signals and weak signals always coexist in the physical environment. A new method is presented for weak GPS signal acquisition using variable thresh- old. Through adjusting the thresholds with different non- coherent accumulation times, this method is applicable to all kinds of signals. It has wonderful acquisition efficiency through theory analysis and real signal verification, espe- cially when strong signals and weak signals coexist, it can greatly reduce acquisition time.     

A Formal Approach for Obligation Analysis of E-Commerce

Existing methods for modeling Ecommerce systems （ECSs） focus mostly on either mathematically abstract verification or graphical modeling, and cannot explicitly describe and analyze the obligations of partners. This work presents a new class of Labeled Petri nets for the modeling and analysis of ECSs. And the life cycle of a case and the time/date of firing an action are considered. It can model graphically the dynamic behavior of the systems, and analyze elegantly the obligations. This approach is illustrated with a nontrivial example of the modeling and analysis of the trading process of the Purchase transaction in the Internet open trading protocol.     

Joint Antenna Selection and Robust Beamforming Design in Multi-cell Distributed Antenna System

Most of studies on Distributed Antenna System （DAS） focus on maximizing the sum capacity and perfect channel state information at transmitter （CSIT）. However, CSI is inevitable imperfect in practical wireless networks. Based on the sources of error, there are two models. One assumes error lies in a bounded region, the other assumes random error. Accordingly, we propose two joint antenna selection （AS） and robust- beamforming schemes aiming to minimize the total transmit power at antenna nodes subject to quality of service （QoS） guarantee for all the mobile users （MUs） in multicell DAS. This problem is mathematically intractable. For the bounded error model, we cast it into a semidefinite program （SDP） using semidefinite relaxation （SDR） and S-procedure. For the second, we first design outage constrained robust beamforming and then formulate it as an SDP based on the Bernstein-type inequality, which we generalize it to the multi-cell DAS. Simulation results verify the effectiveness of the proposed methods.     

＂Smart Cafe＂： A Mobile Local Computing System Based On Indoor Virtual Cloud

With network developing and virtualization rising, more and more indoor environment （POIs） such as care, library, office, even bus and subway can provide plenty of bandwidth and computing resources. Meanwhile many people daily spending much time in them are still suffering from the mobile device with limited resources. This situation implies a novel local cloud computing paradigm in which mobile device can leverage nearby resources to facilitate task execution. In this paper, we implement a mobile local computing system based on indoor virtual cloud. This system mainly contains three key components： 1）As to application, we create a parser to generate the ＂method call and cost tree＂ and analyze it to identify resource- intensive methods. 2） As to mobile device, we design a self-learning execution controller to make offtoading decision at runtime. 3） As to cloud, we construct a social scheduling based application-isolation virtual cloud model. The evaluation results demonstrate that our system is effective and efficient by evaluating CPU- intensive calculation application, Memory- intensive image translation application and I/ O-intensive image downloading application.     

Dependability Analysis for Fault-Tolerant Computer Systems Using Dynamic Fault Graphs

Dependability analysis is an important step in designing and analyzing safety computer systems and protection systems. Introducing multi-processor and virtual machine increases the system faults＇ complexity, diversity and dynamic, in particular for software-induced failures, with an impact on the overall dependability. Moreover, it is very different for safety system to operate successfully at any active phase, since there is a huge difference in failure rate between hardware-induced and software- induced failures. To handle these difficulties and achieve accurate dependability evaluation, consistently reflecting the construct it measures, a new formalism derived from dynamic fault graphs （DFG） is developed in this paper. DFG exploits the concept of system event as fault state sequences to represent dynamic behaviors, which allows us to execute probabilistic measures at each timestamp when change occurs. The approach automatically combines the reliability analysis with the system dynamics. In this paper, we describe how to use the proposed methodology drives to the overall system dependability analysis through the phases of modeling, structural discovery and probability analysis, which is also discussed using an example of a virtual computing system.     

Event-Based Reliable H∞ Control for Networked Control System with Probabilistic Actuator Faults

This paper investigates the reliable con- troller design for networked control system with proba- bilistic actuator faults under event-triggered scheme. The key idea is that only the newly states violating specified triggering condition will be transmitted to the controller. Considering the effect of the network transmission delay, event-triggered scheme and probabUistic actuator faults with different failure rates, a new actuator fault model is proposed. Criteria for the exponential stability and criteria for co-designing both the feedback and the trigger param- eters are derived by using Lyapunov functional. These cri- teria are obtained in the form of linear matrix inequalities. A simulation example is employed to show the effectiveness of the proposed method.     

Correcting Image Distortion for Adaptive Cruise Control

One of the main drivers for intelligent transportation systems is safety.Adaptive cruise control,as a common solution for traffic safety,has extended from radars to cameras.Due to high mobility of vehicles and unevenness of roads,the picture quality of cameras has been great challenges for camera-based adaptive cruise control.In this paper,an image distortion correction algorithm is addressed.Our method is based on optical flow technology which is normally applied in motion estimation and video compression research.We are the first to attempt to adapt it in image distortion correction.Two optical flow approaches,the Lucas-Kanade method and the Horn-Schunck method,are selected and compared.The procedure of image distortion correction using the optical flow method has been tested by both synthetic test images and camera images.The experimental results show that the Lucas-Kanade method is more suitable in the correction of image distortion.     

Tissue P Systems with Look-ahead Mode

Tissue P systems are a class of distributed and parallel computing models inspired from inter-cellular communication and cooperation between cells. In this work, a variant of tissue P system, named tissue P sys- tem with look-ahead mode, is discussed for decreasing the inherent non-determinism of tissue P systems and help- ing implementing tissue P systems on computers. Such systems are proved to be universal by simulating register machine, and they are also proved to be able to efficiently solve computationally hard problems by means of a space- time tradeoff, which is illustrated with a polynomial solu- tion to 3-coloring problem.     

Dynamics of a Strengthened Chaotic System and Its Circuit Implementation

To strengthen a chaotic system, a state feedback controller is applied to generate hyperchaotic be- haviors based on the simplified Lorenz system, and a co- ordinate transformation is used for converting topologi- cal structure of the hyperchaotic system from two wings to four wings. Complex dynamics of the hyperchaotic and four-wing attractor system are analyzed and verified by Lyapunov exponent spectrums, bifurcation diagrams, phase portraits, Poincare sections and circuit realization. The circuit experiment results are agreed well with the simulation results, and it lays a good foundation for the chaotic secure communication.     

Automatic Design of P Systems for Five Basic Arithmetic Operations within One Framework

To solve the programmability of a mem- brane system, this paper presents an automatic design method of a cell-like P system framework for performing five basic arithmetic operations. This method proved that different P systems can be designed with same framework by programming. A technique is introduced to remove re- dundant rules in the process of the design of a P system. The effectiveness and feasibility of this method is verified by experimental results.     

Design and Implementation of a Novel HomePlug-Based Solution for Low Cost and High Performance Smart Home Networking

As the smart home is the end-point power consumer, it is the major part to be controlled in a smart micro grid. There are so many challenges for implementing a smart home system in which the most important ones are the cost and simplicity of the implementation method. It is clear that the major share of the total cost is referred to the internal controlling system network; although there are too many methods proposed but still there is not any satisfying method at the consumers’ point of view. In this paper, a novel solution for this demand is proposed, which not only minimizes the implementation cost, but also provides a high level of reliability and simplicity of operation; feasibility, extendibility, and flexibility are other leading properties of the design.     

Applying System Thinking to Learn from Accident of Modern Automatic Control Systems

Modern societies increasingly rely on auto- matic control systems. These systems are hardly pure tech-nical systems; instead they are complex socio-technical sys- tems, which consist of technical elements and social components. It is necessary to have a systematic approach to analyze these systems because it is growing evidence that accidents from these systems usually have complex causal factors which form an interconnected network of events, rather than a simple cause-effect chain. We take railway Train control systems （TCS） as an example to demonstrate the importance of the socio-technical approach to analyze the system. The paper presents an investigation of recent high-speed railway accident by applying STAMP - one of the most notable socio-technical system analysis tech- niques, outlines improvements to the system which could avoid similar accidents in the future. We also provide our valuable feedback for the use of STAMP.     

Metric-Based and Angle-Rotated Tone Reservation Scheme for PAPR Reduction in OFDM Systems

High Peak-to-average power ratio （PAPR） has been a crucial problem in Orthogonal frequency divi- sion multiplexing （OFDM） systems. In all PAPR reduc- tion schemes, Tone reservation （TR） technology is consid- ered as one of the most promising methods because of no additional distortions no side information, and low imple- mentation cost. For conventional TR approaches, the as- signed value to reserved subcarriers just considers one peak value and this brings peak value up again easily. In this paper, a novel scheme named Metric-based angle-rotated （MBAR） for TR is presented. The scheme employs a met- ric to measure how much each subcarrier contributes to the output signal samples of large magnitude and then subcarriers with the largest positive metrics are selected to reduce PAPR. The simulation results show that when the reserved subcarriers number is 1.46 percent, the PAPR gain of the proposed method can achieve 0.4？dB at least at the probability of 10-3.