Comments on “The Extreme Learning Machine”

This comment letter points out that the essence of the “extreme learning machine (ELM)” recently appeared has been proposed earlier by Broomhead and Lowe and Pao , and discussed by other authors. Hence, it is not necessary to introduce a new name “ELM.”      

Are More Features Better? A Response to Attributes Reduction Using Fuzzy Rough Sets

A recent Transactions on F uzzy Systems paper proposing a new fuzzy-rough feature selector (FRFS) has claimed that the more attributes remain in datasets, the better the approximations and hence resulting models. [Tsang , IEEE Trans. Fuzzy Syst. , vol. 16, no. 5, pp. 1130–1141]. This claim has been used as a primary criticism of the original FRFS method [Jensen and Shen, IEEE Trans. Fuzzy Syst., vol. 15, no. 1, pp. 73–89, Feb. 2007]. Although, in certain applications, it may be necessary to consider as many features as possible, the claim is contrary to the motivation behind feature selection concerning the curse of dimensionality, the presence of redundant and irrelevant features, and the large amount of literature documenting observed improvements in modeling techniques following data reduction. This letter discusses this issue, as well as two other issues raised by Tsang [IEEE Trans. Fuzzy Syst., vol. 16, no. 5, pp. 1130–1141, Oct. 2008] regarding the original algorithm.      

Large Scale Nonlinear Control System Fine-Tuning Through Learning

Despite the continuous advances in the fields of intelligent control and computing, the design and deployment of efficient large scale nonlinear control systems (LNCSs) requires a tedious fine-tuning of the LNCS parameters before and during the actual system operation. In the majority of LNCSs the fine-tuning process is performed by experienced personnel based on field observations via experimentation with different combinations of controller parameters, without the use of a systematic approach. The existing adaptive/neural/fuzzy control methodologies cannot be used towards the development of a systematic, automated fine-tuning procedure for general LNCS due to the strict assumptions they impose on the controlled system dynamics; on the other hand, adaptive optimization methodologies fail to guarantee an efficient and safe performance during the fine-tuning process, mainly due to the fact that these methodologies involve the use of random perturbations. In this paper, we introduce and analyze, both by means of mathematical arguments and simulation experiments, a new learning/adaptive algorithm that can provide with convergent, an efficient and safe fine-tuning of general LNCS. The proposed algorithm consists of a combination of two different algorithms proposed by Kosmatopoulos (2007 and 2008) and the incremental-extreme learning machine neural networks (I-ELM-NNs). Among the nice properties of the proposed algorithm is that it significantly outperforms the algorithms proposed by Kosmatopoulos as well as other existing adaptive optimization algorithms. Moreover, contrary to the algorithms proposed by Kosmatopoulos , the proposed algorithm can operate efficiently in the case where the exogenous system inputs (e.g., disturbances, commands, demand, etc.) are unbounded signals.      

A Cost-Efficient Secure Multimedia Proxy System

Due to limited server and network capacities, proxies are introduced for streaming applications to cache multimedia content from the media source to enable a scalable service and to improve the user experience. In this paper we first review the security aspect of a proxy encryption framework recently presented by Yeung featuring the multikey RSA technique. Then addressing the performance aspect, we propose a redesigned cost-efficient architecture, which is based on a media key management mechanism substantially different from Yeung 's framework and improves the overall system significantly.      

High-Pitch Formant Estimation by Exploiting Temporal Change of Pitch

This paper considers the problem of obtaining an accurate spectral representation of speech formant structure when the voicing source exhibits a high fundamental frequency. Our work is inspired by auditory perception and physiological studies implicating the use of pitch dynamics in speech by humans. We develop and assess signal processing schemes aimed at exploiting temporal change of pitch to address the high-pitch formant frequency estimation problem. Specifically, we propose a 2-D analysis framework using 2-D transformations of the time–frequency space. In one approach, we project changing spectral harmonics over time to a 1-D function of frequency. In a second approach, we draw upon previous work of Quatieri and Ezzat , , with similarities to the auditory modeling efforts of Chi , where localized 2-D Fourier transforms of the time–frequency space provide improved source-filter separation when pitch is changing. Our methods show quantitative improvements for synthesized vowels with stationary formant structure in comparison to traditional and homomorphic linear prediction. We also demonstrate the feasibility of applying our methods on stationary vowel regions of natural speech spoken by high-pitch females of the TIMIT corpus. Finally, we show improvements afforded by the proposed analysis framework in formant tracking on examples of stationary and time-varying formant structure.      

An ergonomic evaluation of VDTs“”

Eight VDTs of different trademarks were analysed in relation to the following properties:

( a) Contrasts of luminance between the screens on the one hand and source documents, as well as other surfaces of the VDT, on the other.

(b) Oscillation degree, sharpness and stability of characters.

( c) Face and legibility of characters.

( d) Dimensions, mobility and reflection degrees of the keyboards.

Special equipment was developed and standardized conditions were applied to the measurements.

The eight VDTs showed essential differences for all the parameters, which might be partially responsible for eye strain and postural complaints. It can be concluded that customers should pay more attention to ergonomic qualities when choosing a VDT. But such an endeavour remains useless if the customer does not, at the same time, look for a proper design of the whole workstation including the working environment.     

Fast Dynamics of an Eel-Like Robot—Comparisons With Navier–Stokes Simulations

This paper proposes a dynamic model of the swim of elongated fish suited to the online control of biomimetic eel-like robots. The approach can be considered as an extension of the original reactive “large elongated body theory” of Lighthill to the 3-D self-propulsion to which a resistive empirical model has been added. While all the mathematical fundamentals have been detailed by Boyer . (http://www.irccyn.ec-nantes.fr/hebergement/Publications/2007/3721.pdf, 2007), this paper essentially focuses on the numerical validation and calibration of the model and the study of swimming gaits. The proposed model is coupled to an algorithm allowing us to compute the motion of the fish head and the field of internal control torque from the knowledge of the imposed internal strain fields. Based on the Newton–Euler formalism of robot dynamics, this algorithm works faster than real time. As far as precision is concerned, many tests obtained with several planar and 3-D gaits are reported and compared (in the planar case) with a Navier–Stokes solver, which, until today have been devoted to the planar swim. The comparisons obtained are very encouraging since in all the cases we tested, the differences between our simplified and reference simulations do not exceed 10%.      

Visualization of Tree-Structured Data Through Generative Topographic Mapping

In this paper, we present a probabilistic generative approach for constructing topographic maps of tree-structured data. Our model defines a low-dimensional manifold of local noise models, namely, (hidden) Markov tree models, induced by a smooth mapping from low-dimensional latent space. We contrast our approach with that of topographic map formation using recursive neural-based techniques, namely, the self-organizing map for structured data (SOMSD) (Hagenbuchner , 2003). The probabilistic nature of our model brings a number of benefits: 1) naturally defined cost function that drives the model optimization; 2) principled model comparison and testing for overfitting; 3) a potential for transparent interpretation of the map by inspecting the underlying local noise models; 4) natural accommodation of alternative local noise models implicitly expressing different notions of structured data similarity. Furthermore, in contrast with the recursive neural-based approaches, the smooth nature of the mapping from the latent space to the local model space allows for calculation of magnification factors—a useful tool for the detection of data clusters. We demonstrate our approach on three data sets: a toy data set, an artificially generated data set, and on a data set of images represented as quadtrees.      

Application of an Equilibrium Model for an Electrified Fluid Interface—Electrospray Using a PDMS Microfluidic Device

An experimental investigation of an electrified fluid interface is presented. The experimental findings are related to a previously developed analytical model of Gubarenko , which is used to determine when a fluidic interface under electrical stress is in equilibrium, and to observations reported in the literature. The effect of key parameters on causing the interface to rupture, form, and maintain an electrospray is investigated. The experimental results reveal the dependence of interface shape on operational parameters, the impact of the interface apex angle on equilibrium, the conditions that cause either dripping mode or cone-jet mode, and the structure of operational domains. This paper confirms predictions made using the analytical model, including the range of parameters that cause the onset and steadiness of a quasi-equilibrium (electrospray) state of the interface. Testing is performed using an electrospray emitter chip fabricated from two layers of Polydimethylsiloxane and one layer of glass. The model and experimental results assist in design decisions for electrospray emitters. Applications of electrified interfaces (electrosprays) are found in mass spectrometry, microfluidics, material deposition, and colloidal thrusters for propulsion.$hfill$[2008-0074]      

On the Generalization of Single Input Rule Modules Connected Type Fuzzy Reasoning Method

Yubazaki have proposed a “single input rule modules connected type fuzzy reasoning method (SIRMs method)” in which its final output is obtained by summarizing the product of importance degree and inference result from single input fuzzy rule modules. This paper proposes a “functional-type SIRMs method,” which is an extended version of the SIRMs method, and clarifies the relationship between the Takagi--Sugeno (T--S) reasoning method and the functional-type SIRMs method. The functional-type SIRMs method can be shown to be transformed to the T--S reasoning method, but generally the conversion to functional-type SIRMs method from the T--S reasoning method is impossible. It is shown, however, that the T--S reasoning method can be transformed to the functional-type SIRMs method when the T--S reasoning method fills some conditions. For this reason, it is shown that the functional-type SIRMs method is the subset of the T--S reasoning method.      

Collision Attacks With Budget Constraints on Key Management Schemes for Secure Multimedia Multicast

We address the problem of distributing a confidentially shared session key to a multimedia multicast group for content protection. In two such schemes proposed by Trappe , the session key is distributed by employing a homogenized rekey message format. We show that their rekey algorithm in itself is vulnerable to specialized collision attacks, in which even a completely passive outer adversary, who never joins the system and thus never knows any secret user keys, can still reveal the session key of the multimedia multicast with an observable probability but only involving a time complexity far lower than an exhaustive search.      

On Exponential Synchronization of Kuramoto Oscillators

In this technical note we study the problem of exponential synchronization for one of the most popular models of coupled phase oscillators, the Kuramoto model. We consider the special case of finite oscillators with distinct, bounded natural frequencies. Our first result derives a lower bound on the coupling gain which is necessary for the onset of synchronization. This bound improves the one derived by Jadbabaie . We then calculate a lower bound on the coupling gain that is sufficient to guarantee oscillator synchronization and derive further sufficient conditions to ensure exponential synchronization of the angular frequencies of all oscillators to the mean natural frequency of the group. We also characterize the coupling gain that is sufficient for the oscillator phase differences to approach any desired compact set in finite time.      

Convergent LMI Relaxations for Quadratic Stabilizability and ${{mathscr H}}_{infty}$ Control of Takagi–Sugeno Fuzzy Systems

This paper investigates the quadratic stabilizability of Takagi–Sugeno (T--S) fuzzy systems by means of parallel distributed state feedback compensators. Using Finsler's lemma, a new design condition assuring the existence of such a controller is formulated as a parameter-dependent linear matrix inequality (LMI) with extra matrix variables and parameters in the unit simplex. Algebraic properties of the system parameters and recent results of positive polynomials are used to construct LMI relaxations that, differently from most relaxations in the literature, provide certificates of convergence to solve the control design problem. Due to the degrees of freedom obtained with the extra variables, the conditions presented in this paper are an improvement over earlier results based only on PÓlya's theorem and can be viewed as an alternative to the use of techniques based on the relaxation of quadratic forms. An extension to cope with guaranteed ${{{mathscr{H}}}}_{!infty }$ attenuation levels is also given, with proof of asymptotic convergence to the global optimal controller under quadratic stability. The efficiency of the proposed approach in terms of precision and computational effort is demonstrated by means of numerical comparisons with other methods from the literature.      

Affective Level Video Segmentation by Utilizing the Pleasure-Arousal-Dominance Information

In this paper, we offer an entirely new view to the problem of high level video parsing. We developed a novel computation method for affective level video segmentation. Its function was to extract emotional segments from videos. Its design was based on the pleasure-arousal-dominance (P-A-D) model of affect representation , which in principle can represent a large number of emotions. Our method had two stages. The first P-A-D estimation stage was defined within framework of the dynamic bayesian networks (DBNs). A spectral clustering algorithm was applied in the final stage to determine the emotional segments of the video. The performance of our method was compared with the time adaptive clustering (TAC) algorithm and an accelerated version of it which we had developed. According to Vendrig , the TAC algorithm was the best segmentation method. Experiment results will show the feasibility of our method.      

Adaptive Data Hiding in Edge Areas of Images With Spatial LSB Domain Systems

This paper proposes a new adaptive least-significant- bit (LSB) steganographic method using pixel-value differencing (PVD) that provides a larger embedding capacity and imperceptible stegoimages. The method exploits the difference value of two consecutive pixels to estimate how many secret bits will be embedded into the two pixels. Pixels located in the edge areas are embedded by a $k$-bit LSB substitution method with a larger value of $k$ than that of the pixels located in smooth areas. The range of difference values is adaptively divided into lower level, middle level, and higher level. For any pair of consecutive pixels, both pixels are embedded by the $k$-bit LSB substitution method. However, the value $k$ is adaptive and is decided by the level which the difference value belongs to. In order to remain at the same level where the difference value of two consecutive pixels belongs, before and after embedding, a delicate readjusting phase is used. When compared to the past study of Wu 's PVD and LSB replacement method, our experimental results show that our proposed approach provides both larger embedding capacity and higher image quality.      

An Adaptive Borrow-and-Return Model for Broadcasting Videos

Yang proposed the concept of borrow-and-return (BR) to leverage the unused server bandwidth when a group of popular videos being broadcast with the FSFC (first segment on the first channel) broadcasting schemes in order to improve the mean waiting time (MWT) of the viewers with the help of additional receiving bandwidth available at the high-end clients. The BR model borrows the bandwidth of the videos with no new-coming viewers during a timeslot to speed up the transmission of the first segments of some of the remaining videos. In this paper, we first address the relative advantage issue among various possible BR schemes by developing a parametric generic BR (GBR) scheme controlled externally by independent borrow parameters. Later, we propose a new BR (NBR) model by incorporating an efficient transmission strategy to reduce the MWT further. Finally, an optimal NBR scheme is developed by augmenting with the optimal borrow parameters, which significantly outperforms the existing and new BR schemes in terms of overall MWT.      

“Electric” Zip Tips™, Preliminary Results

Induction based fluidics (IBF), a new, simple patented approach for transporting liquids in the micro and the macro world, is discussed. Electric fields are shown to energize liquid/s in a container/s to execute an array of purposes. IBF is shown uniquely to energize N liquids in simple off the shelf devices, inductively. We discuss calibration and other issues, as we demonstrate how simple devices can dispense nanoliters and microliters with high precision and accuracy. Furthermore, we show preliminary single and eight channel data for the Zip Tip™ made by Millipore where the device transports liquids “electrically.” We briefly consider how such new devices, “electric” Zip Tips™, might automate desalting and the placement of digests for MALDI TOF analysis.     

A Bioinspired Neural Network for Real-Time Concurrent Map Building and Complete Coverage Robot Navigation in Unknown Environments

Complete coverage navigation (CCN) requires a special type of robot path planning, where the robots should pass every part of the workspace. CCN is an essential issue for cleaning robots and many other robotic applications. When robots work in unknown environments, map building is required for the robots to effectively cover the complete workspace. Real-time concurrent map building and complete coverage robot navigation are desirable for efficient performance in many applications. In this paper, a novel neural-dynamics-based approach is proposed for real-time map building and CCN of autoxnomous mobile robots in a completely unknown environment. The proposed model is compared with a triangular-cell-map-based complete coverage path planning method (Oh , 2004) that combines distance transform path planning, wall-following algorithm, and template-based technique. The proposed method does not need any templates, even in unknown environments. A local map composed of square or rectangular cells is created through the neural dynamics during the CCN with limited sensory information. From the measured sensory information, a map of the robot's immediate limited surroundings is dynamically built for the robot navigation. In addition, square and rectangular cell map representations are proposed for real-time map building and CCN. Comparison studies of the proposed approach with the triangular-cell-map-based complete coverage path planning approach show that the proposed method is capable of planning more reasonable and shorter collision-free complete coverage paths in unknown environments.      

Oscillation criteria for second-order quasi-linear neutral difference equations

In this paper, we obtain some oscillation criteria for the second-order quasi-linear neutral delay difference equation

Full-size image

, where > 0, τ ≥ 0, and σ ≥ 0 are constants, {a_n}, {p_n}, {q_n} are nonnegative sequences and f ε C(R,R).     

Comments on “ -Plane Representation for Type-2 Fuzzy Sets: Theory and Applications”

This comment points out a misnomer and two errors in a previous paper by the author ( IEEE Trans. Fuzzy Syst., vol. 17, no. 5, pp. 1189–1207, Oct. 2009), and because one of the errors relates the term “ $alpha$-plane” to the term “z -slice,” it also connects these two terms more correctly.