scispace - formally typeset
Search or ask a question

Showing papers on "Artifact (error) published in 1974"


Journal ArticleDOI
TL;DR: Nearest neighbor analysis is found to be much more sensitive in its detection of non-random spatial clustering and has the advantage of not being particularly limited in application by problems of size or shape of the area under study, although it does require coordinates for each artifact and cannot be applied when only counts per grid unit are known.
Abstract: The statistical method of nearest neighbor analysis is presented for the study of distributional patterns of artifacts over occupation floors. It is compared with the previously presented method of dimensional analysis of variance. Nearest neighbor analysis is found to be much more sensitive in its detection of non-random spatial clustering. It has the advantage of not being particularly limited in application by problems of size or shape of the area under study, although it does require coordinates for each artifact and cannot be applied when only counts per grid unit are known. On the other hand, nearest neighbor analysis encounters considerable problems in defining the artifact clusters on an area and in comparing the distributions of several artifact types. These problems severely limit the utility of nearest neighbor analysis at the moment. Dimensional analysis of variance handles them better.

111 citations


Journal ArticleDOI
TL;DR: In this paper, the problem of filtering artifact from QRST complexes of ECG records has been approached by the use of a digital, time-varying filter, and the optimum form of this filter assuming uncorrelated, zero-mean, additive noise is presented and shown to be equivalent to estimating the coefficients of an intrinsic component expansion of the complex.
Abstract: The problem of filtering artifact from QRST complexes of ECG records has been approached by the use of a digital, time-varying filter The optimum form of this filter assuming uncorrelated, zero-mean, additive noise is presented and shown to be equivalent to estimating the coefficients of an intrinsic component expansion of the complex Results are reported showing that QRST complexes in limb leads of normals may be accurately represented by only eight terms of the intrinsic component expansion A suboptimum filter is presented and results reported which show that an order of magnitude reduction of the 005 to 100 Hz artifact energy in the filtered complex can be achieved

33 citations



Journal ArticleDOI
TL;DR: Results indicated that EEG recorded from subdermal pin electrodes or from locally anesthetized scalp was free of CSP artifact, and above techniques appear promising for recording EEG free ofCSP artifact.
Abstract: Prevalence of the cephalic skin potential (CSP) artifact was studied in 21 Ss during EEG recording of the Contingent Negative Variation (CNV), averaged evoked response (AER), and verbal free association test. Skin potential response and electro-oculogram (EOG) were also recorded. Subdermal pin electrodes and local anesthesia infusion were employed to eliminate the CSP artifact in the EEG. Results indicated that EEG recorded from subdermal pin electrodes or from locally anesthetized scalp was free of CSP artifact. The EEG recorded from subdermal pin electrodes demonstrated spontaneous potential shifts but appeared adequate for EEG recording of the CNV or the AER. Significant CSP artifact was demonstrated in the EEG of 10 of 21 Ss, both evoked by stimuli (10 Ss) and spontaneous (3 Ss). CSP artifact significantly increased CNV amplitude. CSP artifact significantly increased the AER late positive wave (P3) to infrequent tones. Studies of CNV and AER can be confounded by CSP artifact. Above techniques appear promising for recording EEG free of CSP artifact.

29 citations


Journal ArticleDOI

22 citations


Journal ArticleDOI
TL;DR: The signal comparator eliminates the bubble artifact from the photodetector signal while allowing the signal produced from the fluid segment to remain intact and the instrument is reliable, easy to use, and does not require any adjustments by a technician.
Abstract: Design features and operation of a signal comparator are described. The efficiency of continuous-flow analyzers is improved by allowing the bubbled stream to remain intact as it passes through the colorimeter flow cell. The signal comparator eliminates the bubble artifact from the photodetector signal while allowing the signal produced from the fluid segment to remain intact. The instrument is reliable, easy to use, and does not require any adjustments by a technician.

22 citations


Journal ArticleDOI
TL;DR: In this paper, the authors examined the relevance of artifact to Barber's model of hypnosis and concluded that the major inference drawn from the paradigm regarding the expendability of the concept of trance should be accepted with caution.

10 citations


Journal ArticleDOI
TL;DR: The set-size effect in impression formation has been a highly reliable phenomenon when set size was varied as a within-S factor, but this effect has often been absent in between-S designs.
Abstract: The set-size effect in impression formation has been a highly reliable phenomenon when set size was varied as a within-S factor, but this effect has often been absent in between-S designs. Researchers have questioned the use of one or the other of these design techniques and have consequently labeled as artifactual either the presence or absence of set-size effects. This is a crucial matter for theories of impression formation. Studies are cited which have obtained the set-size effect in a paired-comparisons paradigm where previous design criticisms would not seem to apply, and in between-S designs using specific procedural techniques. It is concluded that the set-size effect is not an artifact.

8 citations



Journal ArticleDOI
TL;DR: It was concluded that cats do not become neurotic following exposure to conflict and that Masserman's findings are best explained as artifacts of the experimental procedures he employed.
Abstract: In an attempt to assess the validity of the phenomenon of \"animal neurosis,\" the behavior of cats exposed to the type of conflict Masserman specified as being critical to the development of \"experimental neurosis\" was contrasted with that of cats simply confined in the conditioning apparatus for the same length of time. Comparison of the groups on the basis of the \"symptoms\" Masserman considered \"neurotic\" did not yield any evidence of neurotic behavior. It was concluded that cats do not become neurotic following exposure to conflict and that Masserman's findings are best explained as artifacts of the experimental procedures he employed.

3 citations





Proceedings ArticleDOI
01 Jan 1974
TL;DR: A real time, on-line EEG analysis strategy is described which incorporates feature extracting algorithms derived from models of human EEG interpretation which has been implemented on a dedicated minicomputer.
Abstract: The extremely complex nature of the electroencephalogram (EEG), and the subtle, nonquantified methods of pattern recognition used by human interpreters have made EEG analysis resistant to automation. Attempts at pattern recognition using multivariate classification procedures have not produced generalizable results due to the inadequate degree and quality of feature extraction prior to classification.A real time, on-line EEG analysis strategy is described which incorporates feature extracting algorithms derived from models of human EEG interpretation. A system based upon this strategy has been implemented on a dedicated minicomputer. It includes: 1) spectral analysis using the Fast Fourier Transform (FFT) to produce continuous estimates of power and coherence; 2) parallel time domain analysis to detect the occurrence of sharp transient events of possible clinical significance; 3) continuous isometric display of spectral and transient functions; 4) spectral and time domain algorithms for the rejection of noncortical and instrumental artifact; 5) heuristics to isolate patterns and events of potential clinical significance; 6) interactive alteration of analysis and display parameters to facilitate manipulation of data from various experimental paradigms; 7) on-line feedback to alter, when necessary, artifact rejection, transient detection and feature extraction decision thresholds.

01 Apr 1974
TL;DR: This paper examined the effects of different testing conditions on self-concept measures and found that performance on the real and ideal self scales was strongly affected by both sequence and time delay and by the interaction of these variables.
Abstract: Many self-concept measures employ several different scales to which the subject responds in a set order at one sitting. This study examined the effects of different testing conditions on such scales. Bill's Index of A0justment and Values was administered to 191 graduate students under two different sequences, and two time delay conditions. The resulto indicate that performance on the real and ideal self scales was sigiaficantly affected by both sequence and time delay and by the interaction of these variables. No differences were found on the self acceptance scale or the discrepancy scores. Implications for educational testing and research are discussed.