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Management of Coastal Navigation Channels Based on Vessel Underkeel Clearance in TransitScully, Brandan 09 December 2016 (has links)
The United States Army Corps of Engineers (USACE) spends approximately $2 billion annually to investigate, construct, and maintain projects in its portfolio of coastal navigation infrastructure. Of that expenditure, approximately $1 billion is spent annually on maintenance dredging to increase the depth of maintained channels. The USACE prioritizes maintenance funding using a variety of metrics reflecting the amount of cargo moving through maintained projects but does not directly consider the reduction in the likelihood for the bottom of a vessel's hull to make contact with the bottom of the channel that results from maintenance dredging investments. Net underkeel clearance, which remains between the channel bottom and the vessel’s keel after considering several important factors that act to increase the necessary keel depth, is used as an indicator of potential reduction of navigation safety. This dissertation presents a model formulated to estimate net underkeel clearance using archival Automatic Identification System (AIS) data and applies it to the federal navigation project in Charleston, South Carolina. Observations from 2011 including 3,961 vessel transits are used to determine the probability that a vessel will have less than 0 feet of net underkeel clearance as it transits from origin to destination. The probability that a vessel had net underkeel clearance greater than or equal to 0 feet was 0.993. A Monte-Carlo approach is employed to prioritize reach maintenance improvement order. A value heuristic is used to rank 7,500 dredging alternatives. 159 options were identified that meet an arbitrarily selected minimum reliability of 0.985. Cost reductions associated with options that met the minimum reliability requirement ranged from 7.7% to 42.6% on an annualized basis. Fort Sumter Range, Hog Island Reach, and Wando Lower Reach are identified as the most important reaches to maintain. The underkeel clearance reliability model developed in this work provides a more accurate representation of the waterway users’ ability to safely transit dredged channels with respect to available depth that is currently available to USACE waterway managers. The transit reliability metric developed provides an accurate representation of the benefit obtained from channel dredging investments, and directly relates the benefit to dredging cost.
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Accurate Prediction of Maritime Trajectories From Historical AIS Data Using Grid-Based MethodsWilson, Paul January 2017 (has links)
In order to aid prediction of future maritime vessel trajectories, it is useful to examine
historical vessel information. It is mandatory for large maritime vessels to broadcast,
among other fields, spatial, speed, and course information using Automatic Identi-
fication System (AIS) transponders. By processing a large historical dataset, it is
possible to predict future vessel trajectories. The region of interest is discretized into
a grid. Then, using offline computations, the historical data are used to determine
second-order transition probabilities and speed information. Predictions will be car-
ried out as an online process. If the destination is known, Dijkstra’s Algorithm is used
to predict the vessel’s path. If the destination is not known, a path can still be de-
termined using transition probabilities, but the prediction will be less accurate. The
path is then smoothed using a line of sight algorithm to produce more realistic paths.
Finally, the speed information is used to predict travel times. Real data were used to
build the graph structure, and predictions were judged against real trajectories. / Thesis / Master of Applied Science (MASc)
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AIS vs. Radar : En undersökning om aktiva befäls åsikter och uppfattning berörande AIS och radarRunberg, Stefan January 2008 (has links)
Arbetet är en fallstudie om aktiva nautikers inställning till användandet av AIS och radar ur en navigatorisk synpunkt. Syftet var att få en uppfattning om hur ett av de nyaste elektroniska hjälpmedlen står sig mot ett av de mer inarbetade och beprövade instrumenten som finns ombord på dagens kommersiella fartyg.För att kunna få en uppfattning om vad nautikerna ansåg utfördes intervjuer ombord på ett svenskt fartyg. Frågorna som ställdes var samma för både AIS och radar för att datan skulle bli jämförbara. De slutsatser som drogs var att AIS som fristående system inte ännu är något som dagens nautiker litar på. Då radarn togs upp till diskussion var mönstret tydligt att systemet ansågs ha hög tillförlitlighet samt att nautikerna näst efter sina egna ögon litar mest på radarn bland de navigatoriska hjälpmedlen. Då en AIS integreras med en radar ansåg samtliga nautiker att tillförlitligheten på båda systemen ökar. / The essay was based upon the active nautical officer’s attitude towards the use of AIS and radar from a navigational point of view. The aim was to get a view of how one of the newest electronic aids keeps well against one of the most and the well-tried instruments that are found onboard on today's commercial vessels. In order to receive an insight the nautical officer’s opinions interviews were conducted onboard a Swedish merchant vessel. The questions that were asked were the same about both AIS and radar in order to get comparable data. The conclusions that were drawn were that AIS as an independent system is not yet something that today's nautical officers trust. When the radar was taken up to discussion all the interviewees stated that the system had high reliability and that it is the second most reliable after their own eyes among the navigational aids. The reliability of both systems increases when an AIS is integrated with a radar according to the result.
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The effect of environment, strategy and organizational characteristics on the performance of accounting information systems.Chang, Yeun-Wen 25 June 2002 (has links)
Abstract
The purpose of the study was to determine the effects of environment, strategy, and organizational characteristics on the performance of accounting information systems (AIS). The degree of environment competition (EC) and perceived environmental uncertainty (EU) were adopted as the variables of environment. This research divided strategy into four dimensions: cost leadership (CL), marketing differential (MD), innovation differential (ID), and strategy breadth (SB). Organizational characteristics were measured by organic organization structure (OS) and task uncertainty (TU). The research also chose information scope (IS), timeliness (TI), aggregation (AG) and integration (IN) as the AIS characteristics to be studied within each dimension. User participation (UP) and top management support (TS) were adopted as the variables of organization support. User satisfaction (US), operation improvement (OP), and managerial performance (MP) were used as the surrogate to measure the performance of AIS. The responses of 143 managers were drawn from a cross-industry sample in Taiwan. The path analysis, MANOVA, and OLS regression were employed to test the hypotheses. The empirical results were as follow:
First, the study illustrated the result of research model. (a) The degree of EC has direct and significant effect on IS and IN. And EU only has significant effect on IS. Besides, EC also has direct and significant effect on UP and TS. (b) This research find that CL has significant negative effect on IS, AG, IN, and TS. MD also has significant negative effect on AG and IN. CL, MD, ID, and SB were all have positive effect on TI. (c) OS has positive effect on IS, IN, and TS. TU has positive effect on IS. (d) AG and IN have positive effects on US, OP, and MP. IS has positive effect on US and TI has positive effect on MP. Finally, UP also has positive effect on US and MP.
Second, the effect of strategy on the characteristics of AIS and organization support. (a) The enterprises pursuing MD, ID, or SB strategy need more broad-scope and higher integration information than adopting CL strategy enterprise. (b) The enterprises pursuing CL, MD, or ID strategy need more timely information than adopting SB strategy enterprise. (c) The enterprises pursuing SB strategy need more aggregation information than adopting CL strategy enterprise. (d) The enterprises pursuing MD, ID, or SB strategy put more emphasis than adopting CL strategy enterprise on the UP and TS.
Third, the effect of contingency factors. (a) When a company facing higher degree of EC and EU, more broad-scope information could effectively enhance user satisfaction, operation improvement and managerial performance. (b) When a company pursuing CL strategy, higher degree of aggregation information will improve operation procedure. When a company¡¦s goal was for marketing differential, more timely and integration information were needed and less aggregated information should be provided for a better performance of OP and MP. When a company was pursuing ID strategy, AIS should provide more timely information. When a company was pursuing SB strategy, more emphasis should be on aggregation and integration information. (c) When a company pursuing MD strategy, OS structure, or facing higher TU, the emphasis on UP will improve US and MP.
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AIS vs. Radar : En undersökning om aktiva befäls åsikter och uppfattning berörande AIS och radarRunberg, Stefan January 2008 (has links)
<p>Arbetet är en fallstudie om aktiva nautikers inställning till användandet av AIS och radar ur en navigatorisk synpunkt. Syftet var att få en uppfattning om hur ett av de nyaste elektroniska hjälpmedlen står sig mot ett av de mer inarbetade och beprövade instrumenten som finns ombord på dagens kommersiella fartyg.För att kunna få en uppfattning om vad nautikerna ansåg utfördes intervjuer ombord på ett svenskt fartyg. Frågorna som ställdes var samma för både AIS och radar för att datan skulle bli jämförbara. De slutsatser som drogs var att AIS som fristående system inte ännu är något som dagens nautiker litar på. Då radarn togs upp till diskussion var mönstret tydligt att systemet ansågs ha hög tillförlitlighet samt att nautikerna näst efter sina egna ögon litar mest på radarn bland de navigatoriska hjälpmedlen. Då en AIS integreras med en radar ansåg samtliga nautiker att tillförlitligheten på båda systemen ökar.</p> / <p>The essay was based upon the active nautical officer’s attitude towards the use of AIS and radar from a navigational point of view. The aim was to get a view of how one of the newest electronic aids keeps well against one of the most and the well-tried instruments that are found onboard on today's commercial vessels. In order to receive an insight the nautical officer’s opinions interviews were conducted onboard a Swedish merchant vessel. The questions that were asked were the same about both AIS and radar in order to get comparable data. The conclusions that were drawn were that AIS as an independent system is not yet something that today's nautical officers trust. When the radar was taken up to discussion all the interviewees stated that the system had high reliability and that it is the second most reliable after their own eyes among the navigational aids. The reliability of both systems increases when an AIS is integrated with a radar according to the result.</p>
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Fusion de données AIS et radar pour la surveillance maritime / Fusion of AIS and radar data for maritime surveillanceManzoni Vieira, Fábio 30 November 2017 (has links)
Dans le domaine de la surveillance maritime, les systèmes coopératifs d’identification et de positionnements tels que l’AIS (Automatic Identification System) sont souvent couplés à des systèmes d’observation de navires non coopératifs comme les Radars à Synthèse d’Ouverture (RSO). Dans ce contexte, la fusion des données AIS et Radar peut améliorer la détection de certains navires et d’identifier éventuels scénarii de surveillance. Le premier chapitre introduit les systèmes et détaille la structure des données AIS et Radar ainsi que le traitement du signal utilisé. Le deuxième chapitre présente l’apport potentiel de l’utilisation conjointe des données brutes Radar et AIS pour la détection de navires à l’aide d’un test basé sur le rapport des vraisemblances maximales (test GLRT). Bien que les performances soient encourageantes, la mise en pratique du détecteur en temps-réel semble compliquée. Le troisième chapitre présente une alternative sous-optimale qui explore les données brutes Radar et une carte des positions de bateaux provenant de l’AIS. Contrairement au chapitre deux, en plus de la détection simultanée par l’AIS et radar, les cas où seul l’un des systèmes détecte un objet peuvent maintenant être distinguées. Le problème est formalisé par deux tests d’hypothèses binaires successifs. Le test proposé est moins sensible à la proximité et à la densité des navires qu’un détecteur radar classique. Le quatrième chapitre présente le simulateur développé pour tester les algorithmes sur différents scénarii de surveillance, à savoir un scénario de piraterie sur un navire civil, un transbordement illégal et une navigation dans un environnement dense. / In the maritime surveillance domain, cooperative identification and positioning systems such as AIS (Automatic Identification System) are often coupled with non-cooperative systems for ship observation such as Synthetic Aperture Radar (SAR). In this context, the fusion of AIS and Radar data can improve the detection of certain vessels and possible identify some maritime surveillance scenarios. The first chapter introduces both AIS and Radar systems, details the data structure as well as the related signal processing. The second chapter presents the potential contribution of the joint use of raw Radar and AIS data for the detection of vessels using a generalized likelihood ratio test (GLRT). Although the performance is encouraging, in practice the implementation in real-time of the detector seems complicated. As alternative, the third chapter presents a suboptimal detection method that explores Radar raw data and a positioning map of vessels obtained from the AIS system. Differently from chapter two, in addition to the simultaneous detection by both AIS and radar, the cases where only one of the systems detects an object can now be distinguished. The problem is formalized by two successive binary hypotheses test. The results suggests that the proposed detector is less sensitive to the proximity and density of ships than a conventional radar detector. The fourth chapter presents the simulator developed to test the algorithms on different surveillance scenarios, namely a civilian ship piracy scenario, an illegal cargo transhipment and a scenario of navigation in a dense environment.
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Proving the Applicability of the Theory of Regulation and the Economic Theory of Regulatory Constraint to American Indian Studies (AIS): A Case Study in Federal Indian Law and PolicyWeinzettle, Christina January 2010 (has links)
The Theory of Regulation and the Economic Theory of Regulatory Constraint have not yet been adapted by American Indian Studies scholars to explain and analyze the federal regulations connected with Federal Indian Law and Policy. It is the intention of this thesis to prove the applicability of these theories to the law and policy concentration of American Indian Studies. The adaptation of these two theories could impact how federal regulations affecting Indian Country are viewed and interpreted. An examination of Federal Indian policy, specifically the regulations (43 CFR 10) promulgated for the Native American Graves Protection and Repatriation Act (NAGPRA) and the National Historic Preservation Act (NHPA) Section 106 tribal consultation processes (36 CFR PART 800) can provide a case study for understanding the applicability of the Theory of Regulation and the Economic Theory of Regulatory Constraint to a common regulatory process in Federal Indian Law.
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Functional analysis of androgen receptor gene mutations identified in patients with androgen insensitivity syndromeBevan, Charlotte Lynne January 1996 (has links)
No description available.
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Software Defined Radio for Maritime Collision Avoidance ApplicationsHumphris, Les January 2015 (has links)
The design and development of a software defined radio (SDR) receiver prototype has been completed. The goal is to replace the existing automatic identification system (AIS) manufactured by Vesper Marine with a software driven system that reduces costs and provides a high
degree of reconfigurability. One of the key concepts of the SDR is the consideration of directly digitizing the radio frequency (RF) signal using subsampling. This idea arises from the ambition to implement an analog-to-digital converter (ADC) as close to the antenna interface as
practically possible. Thus, majority of the RF processing is encapsulated within in the digital domain. Evaluation of a frequency planning strategy that utilizes a combination of subsampling and oversampling will illustrate how the maritime bandwidth is aliased to a lower frequency. An analog front-end (AFE) board was constructed to implement the frequency planning strategy so that the digitized bandwidth can be streamed into a field programmable gate array (FPGA)
for real-time processing. Research is shown on digital front-end (DFE) techniques that condition the digitized maritime signal for baseband processing. The process of a digital down converter (DDC) is conducted by an FPGA, which acquired the in-phase and quadrature signals. By implementing a digital signal processor (DSP) for baseband processing, demodulation on an AIS test signal is evaluated. The SDR prototype achieved a receiver sensitivity of -113dBm, outperforming the required sensitivity of -107dBm specified in the International Electrotechnical Commission (IEC) 62287-1 standard for AIS applications [1].
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The Impact of Information Systems Consultants on Small and Medium-sized Enterprises: A Theory of the Firm PerspectiveBradshaw, Adrian Tyrone January 2012 (has links)
This research aims to show the impact that consultants have on the creation of IS knowledge assets as well as the impact that they have on the development of IS competencies in SMEs. Exploratory case studies involving SMEs and consultants are used to investigate the impact consultants have on SMEs. IS knowledge and IS competencies are important themes that emerge from the exploratory stage of the study. This research further investigates the types of IS knowledge assets and IS competencies that consultants impact in SMEs by conducting further case studies with consultants and SMEs. Several propositions about the types of IS knowledge assets and IS competencies impacted by consultants are developed and tested using a longitudinal single-case study.
The results are analysed using resource-based theory and knowledge-based theory and reveals that consultants contribute to the development of experiential knowledge assets like know-how and experience, routine knowledge assets and systemic knowledge assets by influencing the knowledge creation processes of implementing SMEs. Consultants enhance and contribute to the development of the Management of IT competence which relates to the SME’s ability utilise IS. However, the results also show that consultants compensate for other IS competencies: strategy and vision; sourcing and alignment; and systems and infrastructure. These competencies relate to the SME’s ability to integrate IT with business processes, to source and alignment IT/IS and to engage in business and IS strategic thinking.
It is proposed that in addition to overcoming the knowledge barrier in SMEs, consultants are an essential part of the IS knowledge-creation process. Additionally, consultants compensate for IS competencies which are abilities; however, it is noted that if an on-going relationship develops between the consultants and SMEs then SMEs may, over time, develop IS competencies related to business and IS strategic thinking, management of IT and, sourcing and alignment.
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