416 research outputs found
An Overview on Application of Machine Learning Techniques in Optical Networks
Today's telecommunication networks have become sources of enormous amounts of
widely heterogeneous data. This information can be retrieved from network
traffic traces, network alarms, signal quality indicators, users' behavioral
data, etc. Advanced mathematical tools are required to extract meaningful
information from these data and take decisions pertaining to the proper
functioning of the networks from the network-generated data. Among these
mathematical tools, Machine Learning (ML) is regarded as one of the most
promising methodological approaches to perform network-data analysis and enable
automated network self-configuration and fault management. The adoption of ML
techniques in the field of optical communication networks is motivated by the
unprecedented growth of network complexity faced by optical networks in the
last few years. Such complexity increase is due to the introduction of a huge
number of adjustable and interdependent system parameters (e.g., routing
configurations, modulation format, symbol rate, coding schemes, etc.) that are
enabled by the usage of coherent transmission/reception technologies, advanced
digital signal processing and compensation of nonlinear effects in optical
fiber propagation. In this paper we provide an overview of the application of
ML to optical communications and networking. We classify and survey relevant
literature dealing with the topic, and we also provide an introductory tutorial
on ML for researchers and practitioners interested in this field. Although a
good number of research papers have recently appeared, the application of ML to
optical networks is still in its infancy: to stimulate further work in this
area, we conclude the paper proposing new possible research directions
Integrative clustering by non-negative matrix factorization can reveal coherent functional groups from gene profile data
Recent developments in molecular biology and tech- niques for genome-wide data acquisition have resulted in abun- dance of data to profile genes and predict their function. These data sets may come from diverse sources and it is an open question how to commonly address them and fuse them into a joint prediction model. A prevailing technique to identify groups of related genes that exhibit similar profiles is profile-based clustering. Cluster inference may benefit from consensus across different clustering models. In this paper we propose a technique that develops separate gene clusters from each of available data sources and then fuses them by means of non-negative matrix factorization. We use gene profile data on the budding yeast S. cerevisiae to demonstrate that this approach can successfully integrate heterogeneous data sets and yields high-quality clusters that could otherwise not be inferred by simply merging the gene profiles prior to clustering
Integrative clustering by non-negative matrix factorization can reveal coherent functional groups from gene profile data
Recent developments in molecular biology and tech- niques for genome-wide data acquisition have resulted in abun- dance of data to profile genes and predict their function. These data sets may come from diverse sources and it is an open question how to commonly address them and fuse them into a joint prediction model. A prevailing technique to identify groups of related genes that exhibit similar profiles is profile-based clustering. Cluster inference may benefit from consensus across different clustering models. In this paper we propose a technique that develops separate gene clusters from each of available data sources and then fuses them by means of non-negative matrix factorization. We use gene profile data on the budding yeast S. cerevisiae to demonstrate that this approach can successfully integrate heterogeneous data sets and yields high-quality clusters that could otherwise not be inferred by simply merging the gene profiles prior to clustering
Lipid Fingerprinting by Mass Spectrometry and Laser Light
Lipids have accompanied the emergence of life on Earth. Their tendency to form spherical assemblies in water afforded the separation of organisms from their environment while still allowing controlled exchange of substances between the inside and outside. Lipids enable cellular compartmentalization, modulate membrane proteins, and are involved in intra- and intercellular signaling. The multitude of biological functions is reflected in a tremendous structural diversity, which involves the frequent occurrence of isomers with very specific biological roles. Although highly relevant from a biological perspective, many lipid isomers cannot be distinguished by state-of-the-art mass spectrometry-based analytical techniques.
This work explores the potential of coupling mass spectrometry with infrared spectroscopy to analyze lipid isomers and study lipid fragmentation mechanisms. Infrared spectroscopy adds a structural dimension to the mass spectrometric analysis and previously yielded promising results for other biomolecules. We recorded the first high-resolution infrared spectra of ionized lipids and glycolipids using helium nanodroplets as a cryogenic spectroscopic matrix. Isomeric glycolipids were found to be unambiguously distinguishable based on their diagnostic spectroscopic fingerprints. The high resolution and sensitivity of the technique enabled the relative quantification of low-abundant glycolipid isomers in biological samples by spectral deconvolution. A similar approach was used to analyze double bond isomers in lipids extracted from cancer cells, which revealed significant differences between cancer types. The position and geometry of C C bonds in sphingolipids and fatty acids were rendered visible by amines, which interact with the C C bond and induce diagnostic vibrations. Furthermore, infrared spectroscopy was employed in combination with computational chemistry to gain fundamental understanding of lipid fragmentation in tandem mass spectrometry. A key fragmentation mechanism used for the structural analysis of glycerolipids was thus unveiled and found to occur with high regioselectivity. In addition, unknown fragmentation pathways of vitamin E derivatives were identified by spectroscopy-based assignment of fragment structures. Overall, the coupling of mass spectrometry and infrared spectroscopy has proven to be a powerful approach to study lipid fragmentation mechanisms and to identify biologically relevant lipid isomers from minute sample amounts. The technique is expected to drive important advances in lipid analysis in the near future.Seit seiner Entstehung ist das Leben auf der Erde untrennbar mit Lipiden verbunden. Lipidmembranen ermöglichen die rĂ€umliche Abtrennung von Organellen innerhalb von Zellen, von Zellen innerhalb von Organismen und von Organismen in ihrer unbelebten Umgebung. Lipide beeinflussen zudem die Funktion von Membranproteinen und sind als Botenstoffe am intra- und interzellulĂ€ren Informationsaustausch beteiligt. Die Vielzahl ihrer biologischen Funktionen spiegelt sich in der strukturellen Vielfalt der Lipide und dem hĂ€ufigen Auftreten von Isomeren wider. Viele dieser Isomere, die oft sehr spezifische biologische Funktionen erfĂŒllen, können mit modernen massenspektrometrischen Analysemethoden nicht unterschieden werden.
Durch die Kopplung von Massenspektrometrie mit Infrarotspektroskopie werden neben der Masse von MolekĂŒlen auch strukturelle Informationen erhalten. Die Technik wurde bereits erfolgreich fĂŒr andere BiomolekĂŒle angewendet und wird in dieser Arbeit erstmals fĂŒr die Analyse von isomeren Lipiden und die Untersuchung von Lipidfragmentierung eingesetzt. FĂŒr die Aufnahme von hochaufgelösten Infrarotspektren ionisierter Lipide und Glykolipide wurden Heliumtröpfchen als kryogene spektroskopische Matrix verwendet. Isomere Glykolipide konnten mit dieser Technik eindeutig voneinander unterschieden und in biologischen Proben durch Dekonvolution der Infrarotspektren quantifiziert werden. Eine Ă€hnliche Methode wurde zur relativen Quantifizierung von Doppelbindungsisomeren in Lipidextrakten aus Krebszellen angewendet. Die Analyse zeigte eindeutige Unterschiede in der Isomerenverteilung zwischen verschiedenen Krebstypen. Die Position und Geometrie der C C Bindungen wurden mit Hilfe von Aminen bestimmt, die als Doppelbindungssensoren spezifische Wechselwirkungen mit der C C Bindung eingehen. DarĂŒber hinaus wurde mittels Infrarotspektroskopie und quantenchemischen Methoden der regioselektive Mechanismus einer der wichtigsten Fragmentierungsreaktionen in der Analytik von Glycerolipiden aufgeklĂ€rt. AuĂerdem wurden Fragmentstrukturen von Vitamin E Derivaten spektroskopisch identifiziert und plausible Fragmentierungswege berechnet. Die Ergebnisse dieser Arbeit zeigen, dass mittels kryogener Infrarotspektroskopie ein grundlegendes VerstĂ€ndnis von Fragmentierungsmechanismen in der Lipidanalytik gewonnen werden kann. ZusĂ€tzlich können mit der Technik biologisch relevante Lipidisomere mit minimalem Probenverbrauch unterschieden werden. Die Kopplung von Massenspektrometrie mit Infrarotspektroskopie hat daher groĂes Potential, die nĂ€chsten Entwicklungen in der Lipidanalytik wesentlich voranzutreiben
Church and congregation in community mental health
This thesis reports an experiment made in an Edinburgh parish church to test
two sets of hypotheses: (l) that regular church attenders are more dependency motiÂŹ
vated in their job lives than persons chosen without reference to church e ttachmentsj
and (2) that regular church attenders primarily seek the fulfilment of dependency
needs through their church involvement. The thesis also contains a theological reÂŹ
flection on this study and ends with concrete proposes for the ongoing life of the
church.In the Introduction we presort a body of current thinking about the doctrine
of thellalty. Our experience in parish ministry, hospital chaplaincy, as well as
our study of some commonly held assumptions seemed to raise important questions
about this material. Our questions will be clarified. Then we formulate a set of
working hypotheses and explain the research design for gathering data in the study
of those hypotheses. Finally, we develop our method of doing practical theology -
a method to which we return in Chapter VI as we engage in a theological reflection
on the outcomes.Chapter I is entitled "The Conceptual Framework." Here we present the Motivatlon-Hygiene
Theory of mental health. This is the model with which our work will
be done. A critivue is offered and the usefulness of K-H theory for our project is
explained.Chapter II is entitled "The Method." Here we explain the method chosen to
gather and analyze data pertinent to our hypotheses. The methods are discussed,
a critique offered, and their usefulness for our purposes is indicated,'Chapter III is entitled "The Procedures." A pilot study which was conducted
is reported in this chapter. Here we also present in detail the manner in which
our subjects were selected from a list of "regular church attenders". Profiles
are given of the church and of our subjects. Methods of contacting, Interviewing
and recording our data are also explained.Chapter IV is entitled "The Results." In this chapter our "control group"is
unstructured (to enable testing of the work setting). The chapter documents the
results of our experiment for both sets of hypotheses with which we began.Chapter V is entitled "The Project Conclusions." After presenting the limitations of our work and clarifying certain issues relating to the purpose of our
study, we develop some inferences of our findings. Our conclusions are summarized
and we end with a note on the Important aspects of church life for "mental health".Chapter VI is entitled i'The Theological Reflection." It utilizes the twin
principles of relating theology and psychology which were explained in the introduction, With this model serving as a structure, our data is juxtaposed to some
elements of the theological anthropology of Ronald Gregor Smith, The lines of
contact to the body of material about laity (from the Introduction) are drawn.The Epilogue presents some concrete proposals for the ongoing life of the
church and offers suggestions for further research
Intelligent Sensor Networks
In the last decade, wireless or wired sensor networks have attracted much attention. However, most designs target general sensor network issues including protocol stack (routing, MAC, etc.) and security issues. This book focuses on the close integration of sensing, networking, and smart signal processing via machine learning. Based on their world-class research, the authors present the fundamentals of intelligent sensor networks. They cover sensing and sampling, distributed signal processing, and intelligent signal learning. In addition, they present cutting-edge research results from leading experts
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Mapping the Genomic Context of Mutagenesis
The accumulation of genomic mutations leads to the formation of cancer. For this reason, many efforts have been undertaken to characterise mutational processes in terms of their genomic imprints. A particularly successful approach is matrix-based mutational signature analysis, which identifies prototypical mutation patterns by applying non-negative matrix factorisation to catalogues of single nucleotide variants and other mutation types. However, mutagenesis is a multifaceted event that is affected by the genomic organisation of DNA and cellular processes such as transcription, replication, and DNA repair processes. Moreover, since many mutational processes also generate characteristic multi nucleotide variants, insertion and deletions, and structural variants, it appears valuable to jointly deconvolve broader mutational catalogues to better understand the complex nature of mutagenesis.
In this thesis, I present TensorSignatures, an algorithm to learn mutational signatures jointly across different variant categories as well as their genomic localisation and properties. The analysis of 2,778 primary and 3,824 metastatic cancer genomes of the PCAWG consortium and the HMF cohort shows that practically all signatures operate dynamically in response to various genomic and epigenomic states. The analysis pins differential spectra of UV mutagenesis found in active and inactive chromatin to global genome nucleotide excision repair. TensorSignatures accurately characterises transcription-associated mutagenesis, which is detected in 7 different cancer types. The algorithm also extracts distinct signatures of replication- and double strand break repair-driven mutagenesis by APOBEC3A and 3B with differential numbers and length of mutation clusters. As a fourth example, TensorSignatures reproduces a signature of somatic hypermutation generating highly clustered variants around the transcription start sites of active genes in lymphoid leukaemia, distinct from a more general and less clustered signature of Polη-driven translesion synthesis found in a broad range of cancer types. Finally, I demonstrate TensorSignaturesâ utility by applying it to multiple datasets in various collaboration projects.
Taken together, TensorSignatures adds great detail and refines mutational signature analysis by jointly learning mutation patterns and their genomic determinants. This sheds light on the manifold influences that underlie mutagenesis and helps to pinpoint mutagenic influences which cannot easily be distinguished based on the mutation spectra alone. As mutational signature analysis is an essential element of the cancer genome analysis toolkit, TensorSignatures may help make the growing catalogues of mutational signatures more insightful by highlighting mutagenic mechanisms, or hypotheses thereof, to be investigated in greater depth
Automatic classification of communication logs into implementation stages via text analysis
Abstract Background To improve the quality, quantity, and speed of implementation, careful monitoring of the implementation process is required. However, some health organizations have such limited capacity to collect, organize, and synthesize information relevant to its decision to implement an evidence-based program, the preparation steps necessary for successful program adoption, the fidelity of program delivery, and the sustainment of this program over time. When a large health system implements an evidence-based program across multiple sites, a trained intermediary or broker may provide such monitoring and feedback, but this task is labor intensive and not easily scaled up for large numbers of sites. We present a novel approach to producing an automated system of monitoring implementation stage entrances and exits based on a computational analysis of communication log notes generated by implementation brokers. Potentially discriminating keywords are identified using the definitions of the stages and expertsâ coding of a portion of the log notes. A machine learning algorithm produces a decision rule to classify remaining, unclassified log notes. Results We applied this procedure to log notes in the implementation trial of multidimensional treatment foster care in the California 40-county implementation trial (CAL-40) project, using the stages of implementation completion (SIC) measure. We found that a semi-supervised non-negative matrix factorization method accurately identified most stage transitions. Another computational model was built for determining the start and the end of each stage. Conclusions This automated system demonstrated feasibility in this proof of concept challenge. We provide suggestions on how such a system can be used to improve the speed, quality, quantity, and sustainment of implementation. The innovative methods presented here are not intended to replace the expertise and judgement of an expert rater already in place. Rather, these can be used when human monitoring and feedback is too expensive to use or maintain. These methods rely on digitized text that already exists or can be collected with minimal to no intrusiveness and can signal when additional attention or remediation is required during implementation. Thus, resources can be allocated according to need rather than universally applied, or worse, not applied at all due to their cost
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