• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 265
  • 111
  • 90
  • 36
  • 25
  • 24
  • 21
  • 14
  • 7
  • 6
  • 6
  • 3
  • 3
  • 3
  • 2
  • Tagged with
  • 728
  • 139
  • 137
  • 130
  • 100
  • 89
  • 85
  • 80
  • 78
  • 68
  • 66
  • 63
  • 63
  • 62
  • 62
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Molecular characterization of Ptf1a activity during Xenopus embryogenesis

Hedderich, Marie Charlotte 18 October 2012 (has links)
Für die Bildung eines funktionalen Nervensystems in Vertebraten ist ein Gleichgewicht zwischen inhibitorischen und exzitatorischen Neuronen essentiell. Ein Schlüsselfaktor in der Regulation dieses Gleichgewichts ist der bHLH Transkriptionsfaktor Ptf1a, welcher GABAerge inhibitorische Neurone in der Retina, dem Hinterhirn und im Rückenmark von Vertebraten spezifiziert, zugleich jedoch glutamaterge exzitatorische Neurone unterdrückt. In diesem Zusammenhang benötigt die Aktivität von Ptf1a die Bildung eines trimeren Komplexes, in welchem Ptf1a an ein allgemein exprimiertes E-Protein und an ein Mitglied der Su(H)-Familie bindet. Ptf1a fördert ebenfalls generelle neuronale Differenzierung in X. laevis Embryonen und Explantaten, was darauf hinweist, dass Ptf1a proneurale Aktivität besitzt. In dieser Doktorarbeit wurde die Rolle von Ptf1a im Zusammenhang mit genereller Neurogenese (frühe Funktion) und neuronaler Subtypen-Spezifizierung (späte Funktion) untersucht. Durch eine zeitliche Expressionsanalyse bekannter Gene konnte gezeigt werden, dass Ptf1a durch die Aktivierung von nachgeschalteten Genen, ähnlich dem proneuralen Transkriptionsfaktor Ngn2, in animalen Kappen (naives Ektoderm) zu frühen Zeitpunkten Neurogenese induziert. In späteren Stadien hingegen aktivierte Ptf1a die Expression von Markergenen, die GABAerge Neurone kennzeichnen, während neuronale glutamaterge Markergene von Ngn2 induziert wurden. Eine mutierte Version von Ptf1a (Ptf1aW224A/W242A), welche nicht in der Lage ist, mit dem Kofaktor Su(H) zu interagieren, behielt die Fähigkeit, generelle Neurogenese zu induzieren, nicht aber GABAerge Markergene zu aktivieren. Diese Ergebnisse lassen darauf schließen, dass Ptf1a in der Entwicklung des Nervensystems kontext-spezifische Transkriptionskomplexe bildet: einen Su(H)-unabhängigen Komplex zur Aktivierung genereller Neuorgenese und einen Su(H)-abhängigen Komplex zur Spezifizierung GABAerger Neurone. Da die Zielgene von Ptf1a in der Entwicklung des Nervensystems nicht genau bestimmt sind, wurden zwei unabhängige Transkriptom-Analysen durchgeführt, um das Ptf1a nachgeschaltete genetische Netzwerk aufzuzeigen. In diesen Untersuchungen wurde eine zeitliche Analyse von Genen durchgeführt, die durch wildtyp Ptf1a, Ptf1aW224A/W242A und Ngn2 in X. laevis animalen Kappen aktiviert werden; direkte Zielgene für Ptf1a und Ptf1a/Su(H) wurden bestimmt durch die Aktivierung dieser Transkriptionsfaktoren unter Vorhandensein eines Proteinsyntheseinhibitors (CHX). Durch dieses Vorgehen konnten viele mutmaßlich neue frühe und späte Zielgene von Ptf1a identifiziert werden. Eine weitere Analyse dieser nachgeschalteten Zielgene dürfte darüber Aufschluss geben, wie Ptf1a generelle Neurogenese und neuronale Subtypen-Spezifizierung reguliert.
92

Mazuto perkrovimo proceso naftos terminale imitacinis modelis / The Simulation Model of Reloading of Oil at an Oil Terminal

Kašubienė, Vaida 10 September 2004 (has links)
The purpose of the final work is forming a simulation model of the process of reloading of oil in the oil terminal that would let make a simulation model of accepting oil products by railway to the oil terminal. In order to fulfil the purpose of the final work there were some tasks risen: a conceptual model of reloading process of oil was made, a mathematical model of reloading process of oil was made, too, an aggregate diagram of the simulation model was made an the models of the classes of the program realization were shown as well. The object of the final work is the simulation model of the process of reloading oil created in the oil terminal. Having used an object–oriented simulation system library of simulation modelling JPranas and AgDraw program, the programming realization of simulation model in Java programming system was created. The results of the final work: experiments with the created simulation model of reloading process of oil in order to find out the optimum solution have been created. The created simulation model allows changing these parameters of the model: 1. The intensity of arriving of trains at the railway station. 2. The temperature outside. During modelling the returns got for reloading oil were bring counted and, on the other hand, expenses of oil terminal for reloading oil were being counted as well. The graphic expression of the returns, the expenses and the profits showing the optimum industrial capacity of oil terminal have been presented... [to full text]
93

Sandėlių modeliavimas / Warehouses modelling

Sungaila, Marius 12 June 2008 (has links)
Šiame magistriniame darbe yra aptariama logistikos svarba prekybinėse įmonėse. Atliekamas sandėliavimo ir transportavimo, bei efektyvaus klientų užsakymų tenkinimo naudojant informacines technologijas optimizavimo tyrimas. Panašių programų analizė. Neformaliai ir formaliai Z kalba sandėlių sistemos aprašymas. Bendro prekybos centro ir sandėlio PLA modelio parengimas su agregacine schema ir koncepciniu modeliu, formalia specifikacija. Taip pat išskirtos perėjimų ir išėjimų operacijos. Vėliau bendrojo PLA modelio pritaikymas sandėlių ir prekybos centrų logistikos schemai, agregacinės schemos paruošimas. Formaliųjų Z ir PLA metodų apjungimas kuriant imitacinius modelius, bei imitacinio modelio paruošimas ir jo analizė. Z ir PLA matodų pranašumai ir trūkumai kuriant imitacinius modelius. Išvadose darbo pasiekti rezultatai. / In this graduate work is consideration about logistic importance in commercial companies. Optimization analysis about warehouse and transport functions, effeteness of clients requests using information technologies. The similar programs analysis. Not formally and formally Z language warehouse system descripting. General super market and warehouse PLA model preparation with aggregate scheme and with conceptual model and with formal specification. Also transitions and output operations. Then this general model use for super markets and warehouses and make aggregate scheme. Then integrate efficiency of logistic centres evaluated function. Formal Z and PLA metods coupling to create warehouse imitation model. In conclusion presented analysis work results.
94

Vartotojo įvedamos ir išvedamos informacijos specifikavimo konceptualizavimas / The conceptualization of specification of users' requirements to incoming and out coming information

Trijonis, Vidas 15 January 2005 (has links)
The specification of requirements is one of the most important stages in the development of information system. The correct description is one of the principle goals in preparation of specification of requirements. Well-done specification of information system is a significant support to create software with high functionality, low maintenance and adaptation costs. Filled in document forms play an important role in the analysis of user requirements. This analysis helps to reduce the gap between the user and the system analyst. The methods of form analysis are oriented in creation of an entity relationship scheme. Information system department offering user requirements specification process of functional requirements specification method is similar to natural requirements analysis proceeding. This process begins from specification of users' requirements to incoming and out coming information. This work presents the model and prototype for specification of users' requirements to incoming and out coming information. The model is based on analysis of documents forms given by user. Method is divided into three phases: 1) user incoming and out coming information, 2) data structure analysis, 3) conceptual schema generation. The meta-model repository of requirements specification is presented. The specification process and prototype of specification of incoming and out coming information of user’s requirements are described.
95

PLC Back-up system

Björklund, Johan January 2014 (has links)
The purpose of this bachelor thesis was to investigate the PLC systems used in ABBs breaker factory in Ludvika and to create a system specification suitable to be used in the procurement of a back-up solution for this workshop. This work involved information gathering from different sources, such as archives, physical installations and interviews of maintenance personnel and operators. The results included the requested system specification (in Swedish) including suggestions for pilot test installations and evaluations. The work also resulted in an extensive listing of all PLC systems with placement, typedesignations, expansion modules and other pertinent information. This information ismade available as a macro enabled multipage Microsoft Excel document. A summary and suggestions for follow up work is also included.
96

Role of the Retinoid X Receptors in Skeletal Muscle Development

Le May, Melanie 27 May 2011 (has links)
Pluripotent stem cells have the capacity to develop into different cell lineages and can be manipulated into certain cell types through the use of small molecule inducers. Retinoic acid (RA) signaling through retinoic acid receptors (RAR) and retinoid X receptors (RXR) has the ability to direct lineage determination but has yielded disappointing results in promoting skeletal myogenesis in embryonic stem (ES) cells. RXR is crucial in embryonic development although it is generally considered to act as a silent partner for other nuclear receptors such as RAR. Our findings demonstrate that rexinoid specific signaling enhances skeletal myogenesis and requires β-catenin but not RAR. Moreover, RXR signalling in mouse ES cells can efficiently enhance skeletal myogenesis and closely recapitulates sequential events observed in vivo. Since ES cells closely represent the properties of the developing embryo, efficiently generating skeletal muscle provides a means to further scrutinize signaling pathways in myogenic development in view of developing therapies for muscle related diseases.
97

Classified models for software engineering

Stuart, Gordon F. 30 September 2005 (has links)
In this dissertation it is shown that abstract data types (ADTs) can be specified by the Classified Model (CM) specification language - a first-order Horn language with equality and sort "classification" assertations. It is shown how these sort assertations generalize the traditional syntactic signatures of ADT specifications, resulting in all of the specification capability of traditional equational specifications, but with the improved expressibility of the Horn-with-equality language and additional theorem proving applications such as program synthesis. This work extends corresponding results from Many Sorted Algebra (MSA), Order Sorted Algebra (OSA) and Order Sorted Model (OSM) specification techniques by promoting their syntactic signatures to assertions in the Classified Model Specification language, yet retaining sorted quantification. It is shown how this solves MSA problems such as error values, polymorphism and subtypes in a way different from the OSA and OSM solutions. However, the CM technique retains the MSA and order sorted approach to parameterization. The CS generalization also suggests the use of CM specifications to axiomatize modules as a generalization of variables within Hoare Logic, with application to a restricted, but safe, use of procedures as state changing operations and functions as value returning operations of a module. CM proof theory and semantics are developed, including theorems for soundness, completeness and the existence of a free model.
98

Molecular Control of Pyramidal Neuron Fate Determination in the Developing Neocortex

Parthasarathy, Srinivas 30 June 2014 (has links)
No description available.
99

A Framework for the Specification and Execution of Composite Trading Activities

Si, Yain Whar January 2005 (has links)
In this thesis, a framework for the specification and execution of composite trading activities is presented. We begin by introducing the basic concepts and characteristics of elementary and composite trading activities. Based on these characteristics, we identify the issues associated with composite trading activities and argue the requirements of a frame- work for the specification and execution of those trading activities. In the second chapter, the most relevant work on negotiation protocols, software specification approaches, and recent work on trading activity specification is reviewed. In the third chapter, we analyse the characteristics of negotiation protocols and the information required to adequately represent composite trading activities. In the next two chapters, we introduce two alternative approaches (myopic and forward- looking) for specifying composite trading activities by means of constraints, such as the number of required successful negotiations, the limit price for the items to be traded, and the temporal constraints imposed by all trading parties. A special interface is also defined in each framework to homogenise trading activities with differing negotiation protocols. In myopic trading, composite activities are synchronised according to the information available on the constituent negotiation processes at any point in time. Myopic trading supports iterative negotiation in which trading activities can be renegotiated with new constraints. Myopic trading is suitable for situations in which finer control over the negotiation process is preferred by the trader, and information on previous negotiations as well as future negotiation opportunities are unavailable. Forward-looking trading is based on the generation of negotiation plans detailing the exact time and duration for which trading activities are going to be executed. These plans are generated based on the histories of previous negotiations and future negotiation opportunities. In forward-looking trading, a planning and execution model is designed to maximise the expected utility of the trader. Forward-looking trading is suitable for situations in which a well-planned negotiation process is possible. In the following chapter, two case studies are given to illustrate the applicability of the proposed framework. In the final chapter, we review our framework based on the set of requirements defined for the specification and execution of composite trading activities. In conclusion, we believe that composite trading activities can be effectively specified and executed based on the homogenisation of the various negotiation protocols involved and systematic planning of how these activities are going to be executed.
100

Responsive Workflows: Design, Execution and Analysis of Interruption Policy Models

Belinda Melanie Carter Unknown Date (has links)
Business processes form the backbone of all business operations, and workflow technology has enabled companies to gain significant productivity benefits through the automatic enactment of routine, repetitive processes. Process automation can be achieved by encoding the business rules and procedures into the applications, but capturing the process logic in a graphical workflow model allows the process to be specified, validated and ultimately maintained by business analysts with limited technical knowledge. The process models can also be automatically verified at design-time to detect structural issues such as deadlock and ensure correct data flow during process execution. These benefits have resulted in the success of workflow technology in a variety of industries, although workflows are often criticised for being too rigid, particularly in light of their recent deployment in collaborative applications such as e-business. Generally, many events can impact on the execution of a workflow process. Initially, the workflow is triggered by an external event (for example, receipt of an order). Participants then interact with the workflow system through the worklist as they perform constituent tasks of the workflow, driving the progression of each process instance through the model until its completion. For traditional workflow processes, this functionality was sufficient. However, new generation 'responsive' workflow technology must facilitate interaction with the external environment during workflow execution. For example, during the execution of an 'order to cash' process, the customer may attempt to cancel the order or update the shipping address. We call these events 'interruptions'. The potential occurrence of interruptions can be anticipated but, unlike the other workflow events, they are never required to occur in order to successfully execute any process instance. Interruptions can also occur at any stage during process execution, and may therefore be considered as 'expected, asynchronous exceptions' during the execution of workflow processes. Every interruption must be handled, and the desired reaction often depends on the situation. For example, an address update may not be permitted after a certain point, where this point depends on the customer type, and a shipping charge or refund may be applicable, depending on the original and new delivery region. Therefore, a set of rules is associated with each interruption, such that if a condition is satisfied when the event occurs, a particular action is to be performed. This set of rules forms a policy to handle each interruption. Several workflow systems do facilitate the automatic enforcement of 'exception handling' rules and support the reuse of code fragments to enable the limited specification and maintenance of rules by non-technical users. However, this functionality is not represented in a formal, intuitive model. Moreover, we argue that inadequate consideration is given to the verification of the rules, with insufficient support provided for the detection of issues at design-time that could hinder effective maintenance of the process logic or interfere with the interruption handling functionality at run-time. This thesis presents a framework to capture, analyse and enforce interruption process logic for highly responsive processes without compromising the benefits of workflow technology. We address these issues in two stages. In the first stage, we consider that the reaction to an interruption event is dependent on three factors: the progress of the process instance with respect to the workflow model, the values of the associated case data variables at the time at which the event occurs, and the data embedded in the event. In the second stage, we consider that the reaction to each interruption event may also depend on the other events that have also been detected, that is, we allow interruptions to be defined through event patterns or complex events. We thus consider the issues of definition, analysis and enactment for both 'basic' and 'extended' interruption policy models. First, we introduce a method to model interruption policies in an intuitive but executable manner such that they may be maintained without technical support. We then address the issue of execution, detailing the required system functionality and proposing a reference architecture for the automatic enforcement of the policies. Finally, we introduce a set of formal, generic correctness criteria and a verification procedure for the models. For extended policy models, we introduce and compare two alternative execution models for the evaluation of logical expressions that represent interruption patterns. Finally, we present a thorough analysis of related verification issues, considering both the system and user perspectives, in order to ensure correct process execution and also provide support for the user in semantic validation of the interruption policies.

Page generated in 0.1106 seconds