851 resultados para maintenance facilities


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The high cost and extraordinary demands made on sophisticated air defence systems, pose hard challenges to the managers and engineers who plan the operation and maintenance of such systems. This paper presents a study aimed at developing simulation and systems analysis techniques for the effective planning and efficient operation of small fleets of aircraft, typical of the air force of a developing country. We consider an important aspect of fleet management: the problem of resource allocation for achieving prescribed operational effectiveness of the fleet. At this stage, we consider a single flying-base, where the operationally ready aircraft are stationed, and a repair-depot, where the planes are overhauled. An important measure of operational effectiveness is ‘ availability ’, which may be defined as the expected fraction of the fleet fit for use at a given instant. The tour of aircraft in a flying-base, repair-depot system through a cycle of ‘ operationally ready ’ and ‘ scheduled overhaul ’ phases is represented first by a deterministic flow process and then by a cyclic queuing process. Initially the steady-state availability at the flying-base is computed under the assumptions of Poisson arrivals, exponential service times and an equivalent singleserver repair-depot. This analysis also brings out the effect of fleet size on availability. It defines a ‘ small ’ fleet essentially in terms of the important ‘ traffic ’ parameter of service rate/maximum arrival rate.A simulation model of the system has been developed using GPSS to study sensitivity to distributional assumptions, to validate the principal assumptions of the analytical model such as the single-server assumption and to obtain confidence intervals for the statistical parameters of interest.

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At head of title: Engineering and design.

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Includes appendices.

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Cover title.

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The LAC was requested to review state motor vehicle resources and make recommendations. It focused on three statewide objectives posed by the committees: (1) Determine if any wasteful duplication exists among state-owned vehicle maintenance facilities. (2) Identify any waste or inefficiency in the use of state owned vehicles. (3) Identify unnecessary or personal use of state-owned vehicles.

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Diplomityön kohdeyrityksen liiketoiminta on kokenut viime aikoina merkittäviä muutoksia lisääntyneen volyymin, vaihtuneiden toimitilojen ja konsernin taloudellisesti haastavan tilanteen johdosta. Olosuhteiden muuttuessa ja taloudellisten vaikeuksien kasvaessa on tuotannonohjauksen kehittäminen jäänyt yksikössä takaa-alalle, mikä näkyy pitkittyneinä toimitusaikoina ja laskutusviiveenä, heikkona ohjattavuutena ja täten myös kannattavuuden huonontumisena. Työn tavoitteena onkin tutkia sähkömoottorihuoltotoiminnan nykytilaa ja löytää käytännönläheisiä ja nopeasti toteutettavissa olevia ratkaisuja tuotannonohjauksen kehittämiseksi. Työn teoreettisena viitekehyksenä käytettiin tuotannonohjauksen perusproblema-tiikkaa käsitteleviä teoksia, kuten myös tuotannonohjauksen kehityshankkeisiin liittyvää materiaalia. Tämän lisäksi työhön on pyritty saamaan lisänäkemystä suo-rittamalla benchmarking -vierailuja yhteistyöyrityksiin, jossa on hiljattain suoritettu vastaavan kaltaisia, onnistuneita tuotannonohjauksen kehityshankkeita. Työn empiirinen osuus jaoteltiin kahteen teemaan; nykytila-analyysiin ja toimenpide-ehdotuksiin. Nykytila-analyysi pyrittiin luomaan mahdollisimman kattavaksi sisällyttämällä siihen näkökulmia niin tuotannollisten lukujen kuin henkilöstön nä-kemysten perusteella. Analyysin pohjalta yritykselle laadittiin ehdotuksia käytän-nönläheisistä, nopeasti toteutettavissa olevista toimenpiteistä kuten myös ehdotuksia tuotannon jatkokehityksestä.

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This thesis presents a task-oriented approach to telemanipulation for maintenance in large scientific facilities, with specific focus on the particle accelerator facilities at European Organization for Nuclear Research (CERN) in Geneva, Switzerland and GSI Helmholtz Centre for Heavy Ion Research (GSI) in Darmstadt, Germany. It examines how telemanipulation can be used in these facilities and reviews how this differs from the representation of telemanipulation tasks within the literature. It provides methods to assess and compare telemanipulation procedures as well a test suite to compare telemanipulators themselves from a dexterity perspective. It presents a formalisation of telemanipulation procedures into a hierarchical model which can be then used as a basis to aid maintenance engineers in assessing tasks for telemanipulation, and as the basis for future research. The model introduces a new concept of Elemental Actions as the building block of telemanipulation movements and incorporates the dependent factors for procedures at a higher level of abstraction. In order to gain insight into realistic tasks performed by telemanipulation systems within both industrial and research environments a survey of teleoperation experts is presented. Analysis of the responses is performed from which it is concluded that there is a need within the robotics community for physical benchmarking tests which are geared towards evaluating the dexterity of telemanipulators for comparison of their dexterous abilities. A three stage test suite is presented which is designed to allow maintenance engineers to assess different telemanipulators for their dexterity. This incorporates general characteristics of the system, a method to compare kinematic reachability of multiple telemanipulators and physical test setups to assess dexterity from a both a qualitative perspective and measurably by using performance metrics. Finally, experimental results are provided for the application of the proposed test suite onto two telemanipulation systems, one from a research setting and the other within CERN. It describes the procedure performed and discusses comparisons between the two systems, as well as providing input from the expert operator of the CERN system.

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"Supersedes TM 5-617, 2 June 1945, NAVDOCKS MO-113, September 1963, and AFM 85-4, part D, October 1957"--P. iii.