Current IssuePrevious Issue   Next Issue

Volume 13 No. 1
20 January 2008

2008, 13(1): 1-8.   doi:10.1016/S1007-0214(08)70001-4
Abstract ( 277 )  ( 38 )   Save
This paper reports an investigation of the carrier frequency offset (CFO) compensation in the uplink of the orthogonal frequency division multiple access (OFDMA) system with interleaved subcarrier assignment. The presence of CFOs between the transmitters and the uplink receiver will destroy the orthogonality among the different subcarriers, resulting in inter-carrier interference and multiuser interference. This paper proposes a pseudoinverse CFO compensation method based on the signal structure...

2008, 13(1): 9-16.   doi:10.1016/S1007-0214(08)70002-6
Abstract ( 256 )  ( 65 )   Save
Recently, direct acquisition of GPS P-code has received considerable attention to enhance the anti-jamming and anti-spoofing capabilities of GPS receivers. This paper describes a P-code acquisition method that uses block searches with large-scale FFT to search code phases and carrier frequency offsets in parallel. To limit memory use, especially when implemented in hardware, only the largest correlation result with its position information was preserved after searching a block of resolution cell...

2008, 13(1): 17-22.   doi:10.1016/S1007-0214(08)70003-8
Abstract ( 100 )  ( 32 )   Save
The digital baseband predistorter is an effective technique to compensate for the nonlinearity of power amplifiers (PAs) with memory effects. However, most available adaptive predistorters based on direct learning architectures suffer from slow convergence speeds. In this paper, the recursive prediction error method is used to construct an adaptive Hammerstein predistorter based on the direct learning architecture, which is used to linearize the Wiener PA model. The effectiveness of the scheme i...

2008, 13(1): 23-29.   doi:10.1016/S1007-0214(08)70004-X
Abstract ( 117 )  ( 44 )   Save
Data selection-based summation fusion (DSSF) was developed to overcome the shortcomings of previously developed likelihood ratio tests based on channel statistics (LRT-CS) for the problem of fusing censored binary decisions transmitted over Nakagami fading channels in a wireless sensor network (WSN). The LRT-CS relies on detection probabilities of the local sensors, while the detection probabilities are a priori unknown for uncooperative targets. Also, for Nakagami fading channels, the ...

2008, 13(1): 30-34.   doi:10.1016/S1007-0214(08)70005-1
Abstract ( 204 )  ( 33 )   Save
Single orbit bistatic space-based radar (SBR) is composed of two radars in the same orbit. The characteristics of the clutter Doppler-angle spectrum of a single orbit bistatic SBR show that the slope of the mainbeam clutter spectrum is highly sensitive to the cone angles. Therefore, the minimum detectable velocity of the bistatic system is dependent on the cone angle. Then a new combined working mode of single-orbit bistatic SBR system was developed in which one radar will act as the transmitter...

2008, 13(1): 35-42.   doi:10.1016/S1007-0214(08)70006-3
Abstract ( 200 )  ( 61 )   Save
Navigation and surveillance applications require tracking constant input/bias targets. When the target's trajectory follows a constant input/bias constraint, model mismatching caused by conventional tracking algorithms can be handled by a delayed update filter (DUF). The statistical convergence and stability properties of the delayed update filter were studied to insure the rationality of its steady-state analysis. A steady-state filter gain was then designed for a constant-gain DUF to reduce th...

2008, 13(1): 43-46.   doi:10.1016/S1007-0214(08)70007-5
Abstract ( 107 )  ( 27 )   Save
The almost equal height dual peak spontaneous Brillouin scattering spectrum of a piece of microstructure fiber with a small core was investigated at various temperatures using the heterodyne method. The central frequencies of the two peaks increase linearly with increasing temperature with temperature coefficients of 1.05 MHz/°C and 1.13 MHz/°C. The height difference between the two peaks decreases linearly with a coefficient of −0.06 dB/°C. The results show that microstructure...

2008, 13(1): 47-53.   doi:10.1016/S1007-0214(08)70008-7
Abstract ( 154 )  ( 64 )   Save
Precise, real-time measurements of overflow particle size distributions in hydrocyclones are necessary for accurate control of the comminution circuits. Soft sensing measurements provide real-time, flexible, and low-cost measurements appropriate for the overflow particle size distributions in hydrocyclones. Three soft sensing methods were investigated for measuring the overflow particle size distributions in hydrocyclones. Simulations show that these methods have various advantages and disadvant...

2008, 13(1): 54-58.   doi:10.1016/S1007-0214(08)70009-9
Abstract ( 176 )  ( 36 )   Save
In quantum circuits, importing of additional qubits can reduce the operation time and prevent decoherence induced by the environment. However, excessive qubits may make the quantum system vulnerable. This paper describes how to relax existing qubits without additional qubits to significantly reduce the operation time of the quantum Fourier circuit compared to a circuit without optimization. The results indicate that this scheme makes full use of the qubits relaxation. The concepts can be applied...

2008, 13(1): 59-64.   doi:10.1016/S1007-0214(08)70010-5
Abstract ( 237 )  ( 42 )   Save
Nonlinear least trimmed squares (NLTS) estimator is a very important kind of nonlinear robust estimator, which is widely used for recovering an ideal high-quality signal from contaminated data. However, the NLTS estimator has not been widely used because it is hard to compute. This paper develops an algorithm to compute the NLTS estimator based on a random differential evolution (DE) strategy. The strategy which uses random DE schemes and control variables improves the DE performance. The simula...

2008, 13(1): 65-70.   doi:10.1016/S1007-0214(08)70011-7
Abstract ( 108 )  ( 25 )   Save
This paper presents a method for detecting weak fault signals in chaotic systems based on the chaotic dynamics reconstruction technique and the fuzzy neural system (FNS). The Grassberger-Procaccia algorithm and least squares regression were used to calculate the correlation dimension for the model order estimate. Based on the model order, an appropriately structured FNS model was designed to predict system faults. Through reasonable analysis of predicted errors, the disturbed signal can be extra...

2008, 13(1): 71-77.   doi:10.1016/S1007-0214(08)70012-9
Abstract ( 108 )  ( 61 )   Save
The use of communication networks in control loops has gained increasing attention in recent years due to its advantages and flexible applications. The network quality-of-service (QoS) in those so-called networked control systems always fluctuates due to changes of the traffic load and available network resources. This paper presents an intelligent scheduling controller design approach for a class of NCSs to handle network QoS variations. The sampling period and control parameters in the control...

2008, 13(1): 78-84.   doi:10.1016/S1007-0214(08)70013-0
Abstract ( 108 )  ( 61 )   Save
Power is the major challenge threatening the progress of very large scale integration (VLSI) technology development. In ultra-deep submicron VLSI designs, clock network size must be minimized to reduce power consumption, power supply noise, and the number of clock buffers which are vulnerable to process variations. Traditional design methodologies usually let the clock router independently undertake the clock network minimization. Since clock routing is based on register locations, register plac...

2008, 13(1): 85-90.   doi:10.1016/S1007-0214(08)70014-2
Abstract ( 163 )  ( 37 )   Save
The hardware and software architectures of core service platforms for next-generation networks were analyzed to compute the minimum cost hardware configuration of a core service platform. This method gives a closed form expression for the optimized hardware cost configuration based on the service requirements, the processing features of the computers running the core service platform software, and the processing capabilities of the common object request broker architecture middleware. Three simu...

2008, 13(1): 91-97.   doi:10.1016/S1007-0214(08)70015-4
Abstract ( 174 )  ( 58 )   Save
The busbars in high power neutral point clamped three-level inverters are modeled using the Maxwell Q3D Extractor software, which is based on the partial element equivalent circuits method. The equivalent circuits of the busbars and devices model are simulated in the electric simulator PSIM to analyze the effects of the parasitic inductance on the switching characteristics of the integrated gate commutated thyristor (IGCT) in different topology positions. The simulation results agree well with t...

2008, 13(1): 98-105.   doi:10.1016/S1007-0214(08)70016-6
Abstract ( 213 )  ( 50 )   Save
Network-on-chip (NoC) technology enables a new system-on-chip paradigm, the system-on-network-on-chip (SoNoC) paradigm. One of the challenges in designing application-specific networks is modeling the on-chip system behavior and determining on-chip traffic characteristics. A universal object message level model for SoNoC was defined and an object-oriented methodology was developed to implement this model in hardware and software. The model supports “object to core” synthesis and &ldq...

2008, 13(1): 106-111.   doi:10.1016/S1007-0214(08)70017-8
Abstract ( 157 )  ( 68 )   Save
This paper characterizes quality, budget, and demand as fuzzy variables in a fuzzy vendor selection expected value model and a fuzzy vendor selection chance-constrained programming model, to maximize the total quality level. The two models have distinct advantages over existing methods for selecting vendors in fuzzy environments. A genetic algorithm based on fuzzy simulations is designed to solve these two models. Numerical examples show the effectiveness of the algorithm.

2008, 13(1): 112-116.   doi:10.1016/S1007-0214(08)70018-X
Abstract ( 166 )  ( 47 )   Save
An image and video quality assessment method was developed using neural network and support vector machines (SVM) with the peak signal to noise ratio (PSNR) and the structure similarity indexes used to describe image quality. The neural network was used to obtain the mapping functions between the objective quality assessment indexes and subjective quality assessment. The SVM was used to classify the images into different types which were accessed using different mapping functions. Video quality ...

2008, 13(1): 117-120.   doi:10.1016/S1007-0214(08)70019-1
Abstract ( 109 )  ( 338 )   Save
Capital budgeting is concerned with maximizing the total net profit subject to budget constraints by selecting an appropriate combination of projects. This paper presents chance maximizing models for capital budgeting with fuzzy input data and multiple conflicting objectives. When the decision maker sets a prospective profit level and wants to maximize the chances of the total profit achieving the prospective profit level, a fuzzy dependent-chance programming model, a fuzzy multi-objective depen...