Frequency-domain representation of the well-known time-domain rake combining for the antenna diversity reception of DS-CDMA signals is derived. Two receiver structures using frequency-domain rake combining are presented. Frequency-domain rake combining can alleviate the complexity problem of the time-domain rake arising from too many paths in a severe frequency selective fading channel at the cost of guard interval insertion. The results shown in this paper show a possibility that a DS-CDMA approach still remain to be promising for broadband wireless access technique.

In this paper color image compression using a fuzzy Hopfield-model net based on rough-set reasoning is created to generate optimal codebook based on Vector Quantization (VQ) in Discrete Wavelet Transform (DWT). The main purpose is to embed rough-set learning scheme into the fuzzy Hopfield network to construct a compression system named Rough Fuzzy Hopfield Net (RFHN). First a color image is decomposed into 3-D pyramid structure with various frequency bands. Then the RFHN is used to create different codebooks for various bands. The energy function of RFHN is defined as the upper- and lower-bound fuzzy membership grades between training samples and codevectors. Finally, near global-minimum codebooks in frequency domain can be obtained when the energy function converges to a stable state. Therefore, only 32/N pixels are selected as the training samples if a 3N-dimensional color image was used. In the simulation results, the proposed network not only reduces the consuming time but also preserves the compression performance.

Treating an averaged multiple-trials data or non-averaged single-trial data is a main approach in recent topics on applying independent component analysis (ICA) to neurobiological signal processing. By taking an average, the signal-to-noise ratio (SNR) is increased but some important information such as the strength of an evoked response and its dynamics will be lost. The single-trial data analysis, on the other hand, can avoid this problem but the SNR is very poor. In this study, we apply ICA to both non-averaged single-trial data and averaged multiple-trials data to determine the properties and advantages of both. Our results show that the analysis of averaged data is effective for seeking the response and dipole location of evoked fields. The non-averaged single-trial data analysis efficiently identifies the strength and dynamic component such as α-wave. For determining both the range of evoked strength and dipole location, an analysis of averaged limited-trials data is better option.

In this paper the method of least squares is employed to design an axially symmetric contradirectional multisection coupled - line coupler together with the impedance matching of real generator and load impedances. An error function is constructed for the required coupling (C) based on the squared magnitude of the ratio of the coupler voltage to that at the incident port. Another algorithm based on the reflected and transmitted wave amplitudes is developed by the method of least squares for the design of a coupled - line coupler with impedance matching of different input and output complex impedances and arbitrary coupling and length. The error functions are minimized to determine the coupler geometry, namely the normalized strip conductor widths (u=w/h) and separation (g=s/h) and the coupler length, where h is the substrate thickness. A procedure is presented to provide the initial values of u and g. The computer implementation of the proposed method shows that a proper coupler design is possible for any given coupler length. This is particularly interesting where space limitations impose contraints on the coupler length. The results are favorably compared with available computer simulation softwares.

A combined theory of the micromagnetic and Monte Carlo simulations is established to analyze the thermal property of a nano-sized magnetic grain. The Langevin equation of a grain's magnetic moment is the Landau-Lifshitz equation augmented by a "random-field" term representing the thermal-agitated force. The angular distribution of the magnetic moment of the grain is studied via its time evolution process. The switching of the magnetic moment vector between two energy-minimum states is observed. A simple analytical expression is obtained for the simulated attempt frequency f0, which is related to the magnetic constant of the nano-grain, and agrees well with the phenomenological value.

A reduced complexity multiple-input multiple-output (MIMO) equalizer with ordered successive interference cancellation (OSIC) is proposed for combating intersymbol interference (ISI) and cochannel interference (CCI) over frequency-selective multipath channels. It is developed as a reduced-rank realization of the conventional MMSE decision feedback equalizer (DFE). In particular, the MMSE weight vectors at each stage of OSIC are computed based on the generalized sidelobe canceller (GSC) technique and reduced-rank processing is incorporated by using the conjugate gradient (CG) algorithm for reduced complexity implementation. The CG algorithm leads to a best low-rank representation of the GSC blocking matrix via an iterative procedure, which in turn gives a reduced-rank equalizer weight vector achieving the best compromise between ISI and CCI suppression. With the dominating interference successfully cancelled at each stage of OSIC, the number of iterations required for the convergence of the CG algorithm decreases accordingly for the desired signal. Computer simulations demonstrate that the proposed reduced-rank MIMO DFE can achieve nearly the same performance as the full-rank MIMO MMSE DFE with an effective rank much lower than the dimension of the signal-plus-interference subspace.

Co-containing ferrite thin-film/Mn-Zn ferrite thin-film double-layered perpendicular media were prepared using reactive ECR sputtering and magnetron sputtering methods, and their magnetic and structural properties and recording characteristics were studied. The Mn-Zn ferrite thin-film backlayer had saturation magnetization of 3.5 kG and coercivity of 60 Oe. Reproduced voltage for the Co-containing ferrite thin-film/Mn-Zn ferrite thin-film double-layered medium was about twice of that for the Co-containing ferrite single-layer medium.

In this work, micromagnetic simulations of writing and reading processes in a perpendicular system including a single pole head and recording media with soft underlayer (SUL) have been performed. The noise contribution from the recording layer increased with increasing grain size distribution of the recording layer but that from soft underlayer remained almost a constant at a given linear density. Details of the noise from the soft underlayer will be discussed. Also thermal decay over a long time scale of the recorded bits was investigated by the Langevin equation and the time-temperature scaling method. It was found that at the linear density of 1058 kfci narrower grain size distribution in the recording layer even in the same average grain size is very important in the point of thermal decay than expectation.

A new method for blind watermarking based on quantization is proposed. The proposed scheme embeds a watermark on the lowest wavelet subband in order to be robust. Experimental results demonstrate the robustness of the algorithm against compression and other image processing attacks.

An 18 GHz-band Microwave Monolithic Integrated Circuit (MMIC) diode linearizer using a parallel capacitor with a bias feed resistance is presented. The newly employed parallel capacitor is able to control gain and phase deviations of the linearizer. This implies that the gain deviation of the linearizer can be controlled without changing the phase deviation. The presented linearizer can compensate the distortion of an amplifier sufficiently. The operation principle of the linearizer with the parallel capacitor is investigated. It is clarified that the gain deviation can be adjusted without changing the phase deviation by using the parallel capacitor. Two variable gain buffer amplifiers and the core part of the linearizer which consists of a diode, a bias feed resistor, and a capacitor are fabricated on the MMIC chip. The amplifiers cancel the frequency dependence of the core part of the linearizer to improve bandwidth of the MMIC. Further, the amplifiers contribute to earn low reflection and compensate insertion loss of the linearizer. The MMIC chip is size of 2.5 mm 1 mm. The linearizer has demonstrated improvement of 3rd Inter-Modulation Distortion (IMD3) of 12 dB at 18 GHz and improvement of more than 6 dB between 17.8 GHz and 18.6 GHz.

In 1982, Buckles and Petry proposed fuzzy relational database for incorporating non-ideal or fuzzy information in a relational database. The fuzzy relational database relies on the specification of similarity relation in order to distinguish each scalar domain in the fuzzy database. These relations are reflexive, symmetric, and max-min transitive. In 1989, Shenoi and Melton extended the fuzzy relational database model of Buckles and Petry to deal with proximity relation for scalar domain. Since reflexivity and symmetry are the only constraints placed on proximity relations, proximity relation is considered as a generalization of similarity relation. However, we realized that naturally relation between fuzzy information is not symmetric. Here, we consider using conditional probability relation to represent similarity between two fuzzy data. Related to the properties of conditional probability relation, we introduce an interesting mathematical relation, called weak similarity relation, as generalization of similarity relation as well as proximity relation in which conditional probability relation is regarded as a concrete example of the weak similarity relation. In this paper, we propose design of fuzzy relational database to deal with conditional probability relation for scalar domain. These relations are reflexive and not symmetric. In addition, we define a notion of asymmetric redundant tuple based on two interpretations generalizing the concept of redundancy in classical relational database. In the relation to data querying, we discuss partitioning of domains with the objective of developing similarity class. Finally, we propose a new definition of partial fuzzy functional dependency (PFFD). Fuzzy functional dependency (FFD) as an extension of functional dependency (FD), usually used in design of fuzzy relational database, can be generated by the PFFD. Inference rules that are similar to Armstrong's Axioms for the FFD are both sound and complete.

Implementation issues on generalized multi-protocol label switching (GMPLS) -based photonic switching networks are experimentally analyzed. A resilient control plane architecture using in-fiber and out-of-fiber control channels is proposed to resolve issues of establishing the control plane in out-of-band networks. The resilient control plane is demonstrated in a photonic cross-connect (PXC) -based GMPLS network involving a 1,000 km transmission line. Fast signaling for provisioning and restoration operation is accomplished by implementing in-fiber control channels as primary, and the out-of-fiber control channels effectively operate as secondary and restore messaging of the control information between neighbors. The control channel protection is initiated by the link management protocol (LMP). Using the test bed, optical layer routing operation is investigated to assess the effects on the signal quality of wavelength paths, and transparent routing of the wavelength paths over one-hop and two-hops route is demonstrated within 1 dB difference regarding the Q factor. Stable operation of loss of light (LOL) -triggered restoration is demonstrated by setting the optical level threshold 5 dB higher than the amplified spontaneous emission (ASE) noise level.

This paper proposes a technique for indexing, clustering and retrieving images based on their edge features. In this technique, images are decomposed into several frequency bands using the Haar wavelet transform. From the one-level decomposition sub-bands an edge image is formed. Next, the higher order auto-correlation function is applied on the edge image to extract the edge features. These higher order autocorrelation features are normalized to generate a compact feature vector, which is invariant to shift, image size. We used direction cosine as measure of distance not to be influenced by difference of each image's luminance. Then, these feature vectors are clustered by a self-organizing map (SOM) based on their edge feature similarity. The performed experiments show higher precision and recall of this technique than traditional ways in clustering and retrieving images in a large image database environment.

The present letter introduces a new approach to the construction of a set of ternary arrays having a zero-correlation zone. The proposed array set has a zero-correlation zone for both periodic and aperiodic correlation functions. As such, the proposed arrays can be used as a finite-size array having a zero-correlation zone. The proposed array sets can be constructed from an arbitrary Hadamard matrix. The member size of the proposed array set is close to the theoretical upper bound.

In this paper, we comparatively evaluate two photonic packet switch architectures with WDM-FDL buffers for synchronized variable length packets. The first one is an output buffer type switch, which stores packets in the FDL buffer attached to each output port. Another is a shared buffer type switch, which stores packets in the shared FDL buffer. The performance of a switch is greatly influenced by its architecture and a packet scheduling algorithm. We compare the performances of these two packet switches by applying different packet scheduling algorithms. Through simulation experiments, we show that each architecture has a parameter region for achieving better performance. For the shared buffer type switch, we found that void space introduces unacceptable performance degradation when the traffic load is high. Accordingly, we propose a void space reduction method. Our simulation results show that our proposed method enables to the shared buffer type switch to outperform the output buffer type switch even under high traffic load conditions.

In this paper, we propose a pipelined architecture for an equalizer based on the Multilevel Modified Constant Modulus Algorithm (MMCMA). We also provide the correction factor that mathematically converts the proposed pipelined adaptive equalizer into an equivalent non-pipelined conventional MMCMA based equalizer. The proposed method of pipelining uses modules with 6 filter coefficients, resulting in an overall latency of a single sampling period, along the main transmission line. The basic concept of the proposed architecture is to implement the Finite Impulse Response (FIR) filter and the algorithm portion of the adaptive equalizer, such that the critical path of the whole circuit has a maximum of three complex multipliers and three adders.

Weight divided adaptive control method for a microwave FeedForward Power Amplifier (FFPA) is presented. In this adaptive controller, an output signal of a power amplifier is used as reference signal. Additionally, reference signal is divided by the weight of adaptive filter, so that characteristics of the power amplifier, such as temperature dependence, do not have influence on the convergence performances. The proposed adaptive algorithm and the convergence condition are derived analytically and we clarify that the proposed weight divided adaptive algorithm is more stable than the conventional Normalized Least Mean Square (NLMS) algorithm. Then, the convergence condition considering phase calibration error is discussed. The effectiveness of the proposed algorithm are also verified by the nonlinear simulations of the FFPA having AM-AM and AM-PM nonlinearity of GaAsFET.

In this paper, a predistorter using low frequency intermodulation (IM) signals is proposed. The harmonic generator of the proposed predistorter that consists of a hybrid coupler and four diodes biased separately extracts a second order low frequency IM signal. And with multiplication of second order IM signals, fourth order IM signal is obtained. A vector modulator, modulate fundamental signal with low frequency IM signals, generates predistortion IM signals and controls amplitude/phase of them with modulation factors. As a result, this predistorter is suppressed individual order intermodulation distortion signals of power amplifier effectively. The suggested predistorter has been manufactured to operate in Korea PCS base-station transmitting band (1840-1870 MHz). The test results show that the third order IM is cancelled more than 20 dB and the fifth order IM is cancelled about 10 dB for CW two-tone signals. Also, it's improved the adjacent channel power ratio (ACPR) more than 10 dB for CDMA (IS-95) signals.

A general circuit model of a filter having one cross coupling path is analyzed, and a new theory is developed for the design of a filter with transmission zeros in its stopband. By using the derived formulas, the reactance element values in the cross coupling path are determined readily. The transmission zeros can thus be assigned at desired frequencies. Various design examples are provided, together with simulated results, which validate the proposed theory.

A fuzzy-like phenomenon in a dynamic neural network is demonstrated and analyzed. The network operates as a dynamic associative memory. Each neuron of the dynamic neural network has an all-or-none output and exponentially decaying refractoriness. When several related patterns are stored in the dynamic neural network and an external stimulus with a property shared by two of the stored patterns is applied to the neural network, the output of the neural network dynamically transits between the two stored patterns. The frequency ratio that the network visits the two stored patterns is dependent on the ratio of the Hamming distances between the external pattern and the two stored patterns. This phenomenon is similar to the human decision-making process, some of which characteristics can be described by fuzzy set theory. A framework for the analysis of this phenomenon is proposed, and is used to derive sufficient conditions which ensure the dynamical transition between the two stored patterns. The properties of the transition in the network are also discussed.