COMPARING DISTRIBUTED ACOUSTIC SENSING TO THREE-COMPONENT GEOPHONES IN AN UNDERGROUND MINE

Geophones have become the industry standard for seismic data collection. However, a relatively new method is gaining popularity called Distributed Acoustic Sensing (DAS). DAS uses changes in backscattered light of a fiber-optic cable to detect strain from acoustic energy. The purpose of this project was to make a direct comparison between DAS and three component geophones, specifically in a mining setting. Experiments were done in the Underground Education Mining Center on the campus of Montana Tech. The sources used for this project were vertical sledgehammer shots, oriented shear sledgehammer shots, and blasting caps set off in both unstemmed and stemmed drillholes. Although the explosives performed the best for the geophones, the large amount of energy and its close distance from the fiber seemed to compromise the entire fiber loop. In a one to one comparison, the underground hammer shots seemed to produce data that was a rough match between the DAS traces and the geophone traces. However, the shots on the surface of the mine, specifically the shots oriented inline with the cable, seemed be close to an exact match between trace of the fiber and traces of the geophones. The data suggest that DAS is most useful when the fiber can be oriented in the same direction as particle motion from whatever source is used, whereas the three component geophones can accurately capture data from all sources

A Case Study in Matching Service Descriptions to Implementations in an Existing System

A number of companies are trying to migrate large monolithic software systems to Service Oriented Architectures. A common approach to do this is to first identify and describe desired services (i.e., create a model), and then to locate portions of code within the existing system that implement the described services. In this paper we describe a detailed case study we undertook to match a model to an open-source business application. We describe the systematic methodology we used, the results of the exercise, as well as several observations that throw light on the nature of this problem. We also suggest and validate heuristics that are likely to be useful in partially automating the process of matching service descriptions to implementations.Comment: 20 pages, 19 pdf figure

Research on the Moderating Role of Authorized Leadership in the Relationship Between Mental Capital and Innovative Performance of Knowledge-Oriented Employees

In this paper, through the collection and processing of 206 questionnaires of knowledge-oriented employees and their supervisors to match the effective data, empirical research on the impact of the psychological capital of knowledge-oriented staff on innovative performance through the intermediary mechanism, and the moderating role of authorized leadership in the intermediary mechanism. The results show that the mental capital of knowledge-based staff can influence the intrinsic mechanism of innovation performance through work effort, and authorized leaders can positively adjust the influence of psychological capital on work effort. Meanwhile, authorized leaders can adjust the influence of knowledge workers ' work on their innovation performance. On this basis, this paper proposes that managers can influence the relationship between mental capital of knowledge-based employees and their work and innovation performance through empowering leadership style and give full play to the positive role of knowledge workers in enterprise innovation. Keywords: Empowering Leadership, Knowledge workers, Innovative behavior, Trust mechanis

Constructing Seifert surfaces from n-bridge link projections

This paper presents a new algorithm "A" for constructing Seifert surfaces from n-bridge projections of links. The algorithm produces minimal complexity surfaces for large classes of braids and alternating links. In addition, we consider a family of knots for which the canonical genus is strictly greater than the genus, (g_c(K) > g(K)), and show that A builds surfaces realizing the knot genus g(K). We also present a generalization of Seifert's algorithm which may be used to construct surfaces representing arbitrary relative second homology classes in a link complement.Comment: 19 pages, 15 figure

User evaluation of a pilot terminologies server for a distributed multi-scheme environment

The present paper reports on a user-centred evaluation of a pilot terminology service developed as part of the High Level Thesaurus (HILT) project at the Centre for Digital Library Research (CDLR) in the University of Strathclyde in Glasgow. The pilot terminology service was developed as an experimental platform to investigate issues relating to mapping between various subject schemes, namely Dewey Decimal Classification (DDC), Library of Congress Subject Headings (LCSH), the Unesco thesaurus, and the MeSH thesaurus, in order to cater for cross-browsing and cross-searching across distributed digital collections and services. The aim of the evaluation reported here was to investigate users' thought processes, perceptions, and attitudes towards the pilot terminology service and to identify user requirements for developing a full-blown pilot terminology service

Isometric endomorphisms of free groups

An arbitrary homomorphism between groups is nonincreasing for stable commutator length, and there are infinitely many (injective) homomorphisms between free groups which strictly decrease the stable commutator length of some elements. However, we show in this paper that a random homomorphism between free groups is almost surely an isometry for stable commutator length for every element; in particular, the unit ball in the scl norm of a free group admits an enormous number of exotic isometries. Using similar methods, we show that a random fatgraph in a free group is extremal (i.e. is an absolute minimizer for relative Gromov norm) for its boundary; this implies, for instance, that a random element of a free group with commutator length at most n has commutator length exactly n and stable commutator length exactly n-1/2. Our methods also let us construct explicit (and computable) quasimorphisms which certify these facts.Comment: 26 pages, 6 figures; minor typographical edits for final published versio

A Framework for the Evaluation of Semantics-based Service Composition Approaches

The benefits of service composition are being largely acknowledged in the literature nowadays. However, as the amount of available services increases, it becomes difficult to manage, discover, select and compose them, so that automation is required in these processes. This can be achieved by using semantic information represented in ontologies. Currently there are many different approaches that support semantics-based service composition. However, still little effort has been spent on creating a common methodology to evaluate and compare such approaches. In this paper we present our initial ideas to create an evaluation framework for semantics-based service composition approaches. We use a collection of existing services, and define a set of evaluation metrics, confusion matrix-based and time-based. Furthermore, we present how composition evaluation scenarios are generated from the collection of services and specify the strategy to be used in the evaluation process. We demonstrate the proposed framework through an example. Currently there are mechanisms and initiatives to address the evaluation of the semantics-based service discovery and matchmaking approaches. However, still few efforts have been spent on the creation of comprehensive evaluation mechanisms for semantics-based service composition approaches

Flexible coordination techniques for dynamic cloud service collaboration

The provision of individual, but also composed services is central in cloud service provisioning. We describe a framework for the coordination of cloud services, based on a tuple‐space architecture which uses an ontology to describe the services. Current techniques for service collaboration offer limited scope for flexibility. They are based on statically describing and compositing services. With the open nature of the web and cloud services, the need for a more flexible, dynamic approach to service coordination becomes evident. In order to support open communities of service providers, there should be the option for these providers to offer and withdraw their services to/from the community. For this to be realised, there needs to be a degree of self‐organisation. Our techniques for coordination and service matching aim to achieve this through matching goal‐oriented service requests with providers that advertise their offerings dynamically. Scalability of the solution is a particular concern that will be evaluated in detail