EFFICIENT CALCULATION OF THE AUTOCORRELATION OF BOOLEAN FUNCTIONS WITH THE LARGE NUMBER OF VARIABLES

The autocorrelation of a Boolean function is animportant mathematical concept with various applications. It is a kernel ofmany algorithms with essential applications whose efficiency is directlylimited by the time and space complexity of methods for computing theautocorrelation. These limitations, in this paper, can be overcome by computingthe autocorrelation through Shared Multi-Terminal Binary Decision Diagram(SMTBDD) that are a data structure allowing compact representations of largeBoolean functions. The computation is performed in the spectral domain byexploiting the Wiener-Khinchin theorem and the fast calculation algorithm throughSMTBDDs. It is necessary to develop a specialized decision diagram package withall the standard BDD operations that support fast calculation algorithm throughdecision diagrams and dynamically resizable terminal nodes allows to deal withlarge integers that appear in computing the autocorrelation coefficients. Anexperimental evaluation over benchmarks, confirmed favorably the efficiency ofthe proposed data structure and related algorithms

Facets of forecast evaluation

Forecasts are issued as point or probabilistic predictions, and their performance is measured using consistent scoring functions or proper scoring rules. We identify classes of elementary members of these performance measures and develop diagnostic tools to assist in the ranking of forecasters. Rankings are subject to the choice of evaluation criterion and the sampling variability. We also provide guidance in the computation of a particular scoring rule, the continuous ranked probability score

SEEKING A COMMON THEME: A STUDY OF CERAMIC EFFIGY ARTIFACTS IN THE PRE-HISPANIC AMERICAN SOUTHWEST AND NORTHERN MEXICO USING COMPUTER IMAGE PATTERN RECOGNITION AND PHYLOGENETIC ANALYSIS

Effigy artifacts are found throughout the Pre-Hispanic American Southwest and Northern Mexico (PHASNM), as well as in other cultures around the world, with many sharing the same forms and design features. The earliest figurines within the PHASNM were partial anthropomorphic figurines made from fired clay, dating to between A.D. 287 and A.D. 312 (Morss 1954:27). They were found in a pit house village of Bluff Ruin in the Forestdale Valley of eastern Arizona, and they appeared to be associated with the Mogollon culture. The temporal range of the samples examined in this study is from approximately 200 A.D. to 1650 A.D., and the geographical range includes the Southwestern United States (Arizona, New Mexico, Texas, Colorado, and Utah) and the northcentral section of Mexico (Casas Grandes and the surrounding area). This research looks at the similarities among the markings of ceramic effigy artifacts from the PHASNM, using computer image pattern recognition, design analysis, and phylogenetics, to determine whether their ceramic traditions share a common theme and whether the specific method of social learning responsible for the transmission of information relating to ceramic effigy decoration can be identified. Transmission is possible in one of three ways: vertical transmission, where parents/teachers distribute information by encouraging imitation and sharing learned traditions with children/students (Richerson and Boyd 2005; Shennan 2002); horizontal transmission, where information is transmitted among peers, either from within the individual’s group or from interaction with peers from neighboring populations (Borgerhoff Mulder et al. 2006), and where the individual comes into contact with a wide range of attributes related to the item of interest and then adopts those that allow for the fastest, most economical methods of production and distribution (Eerkens et al 2006; Rogers 1983); and oblique transmission, where information is transmitted by adults, masters, or institutions of elite or higher social status, either internally or externally to the adopting cultural Type (Jensen 2016; Jordan 2014), and where particular traits are adopted or left out in disproportionate ways, creating patterns in localized traditions that can be empirically identified. Horizontal transmission can be broken into two types: unlimited, where contact is not confined to a particular group; and limited, where contact is restricted to a particular set of contacts. Using criteria for each of the categories as set forth by the New Mexico Office of Archaeological Studies Pottery Typology Project, the samples were classified in terms of cultural area (culture), branch, tradition, ware, and type. The research v group consisted of 360 photographic samples represented by 868 images that were resized to a 640x640 pixel format. The images were then examined through computer image pattern recognition (using YOLOv5) and through manual observation. This study resulted in a database representing 230 traits. These traits were assembled into groups by cultural area, branch, tradition, ware, and type, and phylogenetic analysis was applied to show how the different entities transfer information among each other

Advanced Statistical Methods for Atomic-Level Quantification of Multi-Component Alloys

This thesis comprises a collection of papers whose common theme is data analysis of high entropy alloys. The experimental technique used to view these alloys at the nano-scale produces a dataset that, while comprised of approximately 10^7 atoms, is corrupted by observational noise and sparsity. Our goal is to developstatistical methods to quantify the atomic structure of these materials. Understanding the atomic structure of these materials involves three parts: 1. Determining the crystal structure of the material 2. Finding the optimal transformation onto a reference structure 3. Finding the optimal matching between structures and the lattice constantFrom identifying these elements, we may map a noisy and sparse representation of an HEA onto its reference structure and determine the probabilities of different elemental types that are immediately adjacent, i.e., first neighbors, or are one-level removed and are second neighbors. Having these elemental descriptors of a material, researchers may then develop interaction potentials for molecular dynamics simulations, and make accurate predictions about these novel metallic alloys

Advanced Technique and Future Perspective for Next Generation Optical Fiber Communications

Optical fiber communication industry has gained unprecedented opportunities and achieved rapid progress in recent years. However, with the increase of data transmission volume and the enhancement of transmission demand, the optical communication field still needs to be upgraded to better meet the challenges in the future development. Artificial intelligence technology in optical communication and optical network is still in its infancy, but the existing achievements show great application potential. In the future, with the further development of artificial intelligence technology, AI algorithms combining channel characteristics and physical properties will shine in optical communication. This reprint introduces some recent advances in optical fiber communication and optical network, and provides alternative directions for the development of the next generation optical fiber communication technology

Enhanced coding, clock recovery and detection for a magnetic credit card

Merged with duplicate record 10026.1/2299 on 03.04.2017 by CS (TIS)This thesis describes the background, investigation and construction of a system for storing data on the magnetic stripe of a standard three-inch plastic credit in: inch card. Investigation shows that the information storage limit within a 3.375 in by 0.11 in rectangle of the stripe is bounded to about 20 kBytes. Practical issues limit the data storage to around 300 Bytes with a low raw error rate: a four-fold density increase over the standard. Removal of the timing jitter (that is prob-' ably caused by the magnetic medium particle size) would increase the limit to 1500 Bytes with no other system changes. This is enough capacity for either a small digital passport photograph or a digitized signature: making it possible to remove printed versions from the surface of the card. To achieve even these modest gains has required the development of a new variable rate code that is more resilient to timing errors than other codes in its efficiency class. The tabulation of the effects of timing errors required the construction of a new code metric and self-recovering decoders. In addition, a new method of timing recovery, based on the signal 'snatches' has been invented to increase the rapidity with which a Bayesian decoder can track the changing velocity of a hand-swiped card. The timing recovery and Bayesian detector have been integrated into one computation (software) unit that is self-contained and can decode a general class of (d, k) constrained codes. Additionally, the unit has a signal truncation mechanism to alleviate some of the effects of non-linear distortion that are present when a magnetic card is read with a magneto-resistive magnetic sensor that has been driven beyond its bias magnetization. While the storage density is low and the total storage capacity is meagre in comparison with contemporary storage devices, the high density card may still have a niche role to play in society. Nevertheless, in the face of the Smart card its long term outlook is uncertain. However, several areas of coding and detection under short-duration extreme conditions have brought new decoding methods to light. The scope of these methods is not limited just to the credit card

Implementation of spectrum sensing techniques for cognitive radio systems

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This work presents a method for real-time detection of secondary users at the cognitive wireless technologies base stations. Cognitive radios may hide themselves in between the primary users to avoid being charged for spectrum usage. To deal with such scenarios, a cyclostationary Fast Fourier Transform accumulation method (FAM) has been used to develop a new strategy for recognising channel users under perfect and different noise environment conditions. Channel users are tracked according to the changes in their signal parameters, such as modulation techniques. MATLAB® Simulation tool was used to run various modulation signals on channels, and the obtained spectral correlation density function shows successful recognition between secondary and primary signals. We are unaware of previous efforts to use the FAM characteristics or other detection methods to make a distinction between channel users as presented in this thesis. A novel combination of both cognitive radio technology and ultra wideband technology is interdicted in this thesis, looking for an efficient and reliable spectrum sensing method to detect the presence of primary transmitters, and a number of spectrum-sensing techniques implemented in ultra wideband and cognitive radio component (UWB-CR) under different AWGN and fading settings environments. The sensing performance of different detectors is compared in conditions of probability of detection and miss detection curves. Simulation results show that the selection of detectors rely on the different fading scenarios, detector requirements and on a priori knowledge. Furthermore, result showed that the matched filter detection method is suitable for detecting signals through UWB-CR system under various fading channels. A general observation is that the matched filter detector outperforms the other detectors in all scenarios by an average of SNR=-20 dB in the level of probability of detection (Pd) , and the energy detector slightly outperforms the cyclostationary detector, in the level Pd at SNR=-20 dB. Furthermore, the thesis adapts novel detection models of cooperative and cluster cooperative wideband spectrum sensing in cognitive radio networks. In the proposed schemes, wavelet-based multi-resolution spectrum sensing and a proposed approach scheme are utilized for improving sensing performance of both models. On the other hand, cluster based cooperative spectrum sensing with soft combination Equal Gain Combination (EGC) scheme is proposed. The proposed detection models could achieve improvement of transmitter signal detection in terms of higher probability of detection and lower probability of false alarm. In the cooperative wideband spectrum sensing model, using traditional fusion rule, existing worst performance of false alarms by measurement is 78% of the sensing bands at an average SNR=5 dB; this compares with the proposed model, which is by measurement 19% false alarms of scanning spectrum at the same SNR for cluster cooperative wideband spectrum sensing. The proposed combining methods shows improvements of results with a high probability of detection (Pd) and low probability of false alarm (Pf) at an average SNR=-16 dB compared with other traditional fusion methods; this is illustrated through numerical results