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1. Towards Formal Analysis of Artifact-Centr ic Business Process Models: Business Process Management (2007), pp. 288-304.Busine ss process (BP) modeling is a building block for design and management of business processes. Two fundamental aspects of BP modeling are: a formal framework that well integrates both control flow and data, and a set of tools to assist all phases of a BP life cycle. This paper is an initial attempt to address both aspects of BP modeling. We view our investigation as a precursor to the development of a framework and tools that enable automated construction of processes, along the lines of techniques developed around OWL-S and Semantic Web Services. Over the last decade, an artifact-centr ic approach of coupling control and data emerged in the practice of BP design. It focuses on the ?moving? data as they are manipulated throughout a process. In this paper, we formulate a formal model for artifact-centr ic business processes and develop complexity results concerning static analysis of three problems of immediate practical concerns, which focus on the ability to complete an execution, existence of an execution ?deadend?, and redundancy. We show that the problems are undecidable in general, but under various restrictions they are decidable but complete in pspace, co-np, and np; and in some cases decidable in linear time.Kamal Bhattacharya, Cagdas Gerede, Richard Hull, Rong Liu, Jianwen Su
   
   Source: Business Process Management (2007), pp. 288-304.
   
   
2. Modeling Business Contexture and Behavior Using Business Artifacts: Advanced Information Systems Engineering (2007), pp. 324-339.Tradit ional process modeling approaches focus on the activities needed to achieve a business goal. However, these approaches often pose obstacles in consolidating processes across an organization because they fail to capture the informational structure pertinent to the business context or contexture. In this paper, we discuss business artifact-cente red operational modeling. Artifacts capture the contexture of a business and operational models describe how a business goal is achieved by acting upon the business artifact. Business artifacts, such as Purchase Order or Insurance Claim, provide business analysts an additional dimension to model their business. With operational models, they can describe how a business operates by processing business artifacts and adding business value to the artifacts. This approach has been successfully employed in a variety of customer engagements. We summarize our best practices by describing nine operational patterns. Furthermore, we develop a computational model for operational models based on Petri Nets to enable formal analysis and verification thereof.Rong Liu, Kamal Bhattacharya, Frederick Wu
   
   Source: Advanced Information Systems Engineering (2007), pp. 324-339.
   
   
3. Automatic removal of the eye blink artifact from EEG using an ICA-based template matching approach.: Physiol Meas, Vol. 27, No. 4. (April 2006), pp. 425-436.Indepe ndent component analysis (ICA) proves to be effective in the removing the ocular artifact from electroencepha logram recordings (EEG). While using ICA in ocular artifact correction, a crucial step is to correctly identify the artifact components among the decomposed independent components. In most previous works, this step of selecting the artifact components was manually implemented, which is time consuming and inconvenient when dealing with a large amount of EEG data. We present a new method which automatically selects the eye blink artifact components based on the pattern of their scalp topographies, which can be exemplified as a template matching approach. The feasibility of using a fixed template for singling out the eye blink component after ICA decomposition was validated by an experiment in which 18 subjects among the 21 subjects involved exhibited a highly consistent pattern of eye blink scalp topographies. Since only the spatial feature is employed for singling out the eye blink component, the proposed method is very efficient and easy to implement. Objective evaluation of the real results shows that the proposed algorithm can remove the eye blink artifact from the EEG while causing little distortion to the underlying brain activities.Y Li, Z Ma, W Lu, Y Li
   
   Source: Physiol Meas, Vol. 27, No. 4. (April 2006), pp. 425-436.
   
   
4. Removal of the ocular artifact from the EEG: a comparison of time and frequency domain methods with simulated and real data.: Psychophysiolo gy, Vol. 28, No. 1. (January 1991), pp. 114-121.Freque ncy-dependent transfer from EOG to EEG may be insufficiently accounted for by simple time domain regression methods (Gasser, Sroka, & Möcks, 1986; Woestenburg, Verbaten, & Slangen, 1983). In contrast, a multiple-lag time domain regression analysis, using lagged regression of EEG on EOG, must theoretically account for both frequency dependence and independence. Two data sets were constructed, in which the transfer from EOG to EEG was either frequency-inde pendent (constant gain) or frequency-depe ndent. Subsequently, three different correction methods were applied: 1) a simple regression analysis in the time domain; 2) a multiple-lag regression analysis in the time domain; and 3) a regression analysis in the frequency domain. The major results were that, for data set 1, the three methods constructed the original EEG equally well. With data set 2, reconstruction of the original EEG was achieved reasonably well with the frequency domain method and the time domain multiple-lag method, but not with simple time domain regression. These three correction procedures were also applied to real data, consisting of concomitantly recorded EEG and high-variance EOG series. No appreciable differences in outcome of the three methods were observed, and estimated transfer parameters suggested that these data were marked by weak frequency dependence only, which can be accounted for by simple time domain regression (and also by the other two methods).JL Kenemans, PC Molenaar, MN Verbaten, JL Slangen
   
   Source: Psychophysiology, Vol. 28, No. 1. (January 1991), pp. 114-121.
   
   
5. Removal of time-varying gradient artifacts from EEG data acquired during continuous fMRI.: Clin Neurophysiol, Vol. 115, No. 9. (September 2004), pp. 2181-2192.OBJE CTIVE: Recording low amplitude electroencepha lography (EEG) signals in the face of large gradient artifacts generated by changing functional magnetic resonance imaging (fMRI) magnetic fields continues to be a challenge. We present a new method of removing gradient artifacts with time-varying waveforms, and evaluate it in continuous (non-interleav ed) simultaneous EEG-fMRI experiments. METHODS: The current method consists of an analog filter, an EEG-fMRI timing error correction algorithm, and a temporal principal component analysis based gradient noise removal algorithm. We conducted a phantom experiment and a visual oddball experiment to evaluate the method. RESULTS: The results from the phantom experiment showed that the current method reduced the number of averaged samples required to obtain high correlation between injected and recovered signals, compared to a conventional average waveform subtraction method with adaptive noise cancelling. For the oddball experiment, the results obtained from the two methods were very similar, except that the current method resulted in a higher P300 amplitude when the number of averaged trials was small. CONCLUSIONS: The current method enabled us to obtain high quality EEGs in continuous simultaneous EEG-fMRI experiments. SIGNIFICANCE: Continuous simultaneous EEG-fMRI acquisition enables efficient use of data acquisition time and better monitoring of rare EEG events.M Negishi, M Abildgaard, T Nixon, RT Constable
   
   Source: Clin Neurophysiol, Vol. 115, No. 9. (September 2004), pp. 2181-2192.
   
   
6. Nonlinear noise reduction using reference data: Physical Review E, Vol. 63, No. 3. (23 February 2001), 036209.Karsten Sternickel, Arndt Effern, Klaus Lehnertz, Thomas Schreiber, Peter David
   
   Source: Physical Review E, Vol. 63, No. 3. (23 February 2001), 036209.
   
   
7. Removal of FMRI environment artifacts from EEG data using optimal basis sets.: Neuroimage, Vol. 28, No. 3. (15 November 2005), pp. 720-737.The combination of functional magnetic resonance imaging (FMRI) and electroencepha lography (EEG) has received much recent attention, since it potentially offers a new tool for neuroscientist s that makes simultaneous use of the strengths of the two modalities. However, EEG data collected in such experiments suffer from two kinds of artifact. First, gradient artifacts are caused by the switching of magnetic gradients during FMRI. Second, ballistocardio graphic (BCG) artifacts related to cardiac activities further contaminate the EEG data. Here we present new methods to remove both kinds of artifact. The methods are based primarily on the idea that temporal variations in the artifacts can be captured by performing temporal principal component analysis (PCA), which leads to the identification of a set of basis functions which describe the temporal variations in the artifacts. These basis functions are then fitted to, and subtracted from, EEG data to produce artifact-free results. In addition, we also describe a robust algorithm for the accurate detection of heart beat peaks from poor quality electrocardiog raphic (ECG) data that are collected for the purpose of BCG artifact removal. The methods are tested and are shown to give superior results to existing methods. The methods also demonstrate the feasibility of simultaneous EEG/FMRI experiments using the relatively low EEG sampling frequency of 2048 Hz.RK Niazy, CF Beckmann, GD Iannetti, JM Brady, SM Smith
   
   Source: Neuroimage, Vol. 28, No. 3. (15 November 2005), pp. 720-737.
   
   
8. A perspective on needle artifacts in MRI: an electromagneti c model for experimentally separating susceptibility effects: Medical Imaging, IEEE Transactions on, Vol. 19, No. 12. (2000), pp. 1248-1252.A thorough understanding of artifacts caused by metallic instruments is essential for the guidance of interventional procedures by magnetic resonance imaging (MRI), because the accurate localization of each instrument is mandatory for this. In the past, this problem has been addressed by several groups, using theoretical, as well as experimental approaches. The artifacts associated with MRI are caused by geometry distortion and intravoxel dephasing. Usually, both effects mingle in the image, and depending on the pulse sequences and its parameters used for data acquisition, these effects are reflected in the image with different magnitude. Here, the authors shortly present the well-known mathematical background of the two underlying effects. Mathematically , both can be treated separately. Here, authors propose a new electromagneti c model which also allows to experimentally separate the effects better than by comparing spin-echo and gradient-echo images of the same object. With this new model, both effects-geomet ry distortion and intravoxel dephasing-are demonstrated separately using the same gradient-echo pulse sequence for all scans and adjusting the fields of the model properly. Furthermore, as this model allows to adjust both effects independently, it is used to study different weightings of both effects when they appear simultaneously in the image.A Glowinski, G Adam, A Bucker, J van Vaals, RW Gunther
   
   Source: Medical Imaging, IEEE Transactions on, Vol. 19, No. 12. (2000), pp. 1248-1252.
   
   
9. Artifact due to B(0) fluctuations in fMRI: correction using the k-space central line.: Magn Reson Med, Vol. 46, No. 1. (July 2001), pp. 198-201.Magnet ic resonance experiments require the main magnetic field, B(0), to remain very stable. Several external sources, such as moving ferromagnetic objects and/or changing electromagneti c fields, can significantly change the value of B(0) over time. This work describes an apparent displacement along the phase-encoding axis caused by a variation in B(0). This artifact was observed in fMRI images acquired with EPI. The effect was characterized and tested using an immobile phantom. The image displacement motion along the phase-encoding axis closely followed the changes in B(0). The phase of the central line in the Fourier space was successfully used to correct this artifact. Fluctuations in B(0) may result in artifacts that mimic subject head motion, and must be appropriately corrected. Magn Reson Med 46:198-201, 2001.E Durand, PF van de Moortele, M Pachot-Clouard , D Le Bihan
   
   Source: Magn Reson Med, Vol. 46, No. 1. (July 2001), pp. 198-201.
   
   
10. Correction for chemical-shift artifacts in ¹⁹F imaging of PFOB: Simultaneous multislice imaging: Magnetic Resonance in Medicine, Vol. 21, No. 1. (1991), pp. 21-29.One of the difficulties encountered in 19F NMR imaging of fluorinated blood substitutes is that these compounds often exhibit complex multipeak spectra. These peaks result in chemical-shift artifacts along the readout direction and blurred images. In addition, each peak excites a different slice (mis-selection ) when a slice selection gradient is applied during the selective rf pulse. A simultaneous multislice imaging method has been developed to solve the inherent problem of mis-selection. The essence of this method is to use the two strongest peaks of the spectrum to excite controlled different multiple slices simultaneously , with or without a slice gap. The images corresponding to the two spectral lines are then separated from in-and out-of-phase images (Dixon method). This method corrects the problem of mis-selection and either improves the SNR or increases the number of slices over spectrally selective methods which image only one peak. © 1991 Academic Press, Inc.HK Lee, O Nalcioglu, RB Buxton
    
    Source: Magnetic Resonance in Medicine, Vol. 21, No. 1. (1991), pp. 21-29.