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Modeling, Design And Evaluation Of Networking Systems And Protocols Through SimulationLacks, Daniel Jonathan 01 January 2007 (has links)
Computer modeling and simulation is a practical way to design and test a system without actually having to build it. Simulation has many benefits which apply to many different domains: it reduces costs creating different prototypes for mechanical engineers, increases the safety of chemical engineers exposed to dangerous chemicals, speeds up the time to model physical reactions, and trains soldiers to prepare for battle. The motivation behind this work is to build a common software framework that can be used to create new networking simulators on top of an HLA-based federation for distributed simulation. The goals are to model and simulate networking architectures and protocols by developing a common underlying simulation infrastructure and to reduce the time a developer has to learn the semantics of message passing and time management to free more time for experimentation and data collection and reporting. This is accomplished by evolving the simulation engine through three different applications that model three different types of network protocols. Computer networking is a good candidate for simulation because of the Internet's rapid growth that has spawned off the need for new protocols and algorithms and the desire for a common infrastructure to model these protocols and algorithms. One simulation, the 3DInterconnect simulator, simulates data transmitting through a hardware k-array n-cube network interconnect. Performance results show that k-array n-cube topologies can sustain higher traffic load than the currently used interconnects. The second simulator, Cluster Leader Logic Algorithm Simulator, simulates an ad-hoc wireless routing protocol that uses a data distribution methodology based on the GPS-QHRA routing protocol. CLL algorithm can realize a maximum of 45% power savings and maximum 25% reduced queuing delay compared to GPS-QHRA. The third simulator simulates a grid resource discovery protocol for helping Virtual Organizations to find resource on a grid network to compute or store data on. Results show that worst-case 99.43% of the discovery messages are able to find a resource provider to use for computation. The simulation engine was then built to perform basic HLA operations. Results show successful HLA functions including creating, joining, and resigning from a federation, time management, and event publication and subscription.
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Constrained Gaussian Process Regression Applied to the Swaption Cube / Regression för gaussiska processer med bivillkor tillämpad på Swaption-kubenDeleplace, Adrien January 2021 (has links)
This document is a Master Thesis report in financial mathematics for KTH. This Master thesis is the product of an internship conducted at Nexialog Consulting, in Paris. This document is about the innovative use of Constrained Gaussian process regression in order to build an arbitrage free swaption cube. The methodology introduced in the document is used on a data set of European Swaptions Out of the Money. / Det här dokumentet är en magisteruppsats i finansiel matematik på KTH. Detta examensarbete är resultatet av en praktik som ufördes på Nexialog Consulting i Paris.Detta dokument handlar om den innovativa användningen av regression för gaussiska processer med bivillkor för att bygga en arbitragefri swaption kub. Den metodik som introduceras i dokumentet används på en datamängd av europeiska swaptions som är "Out of the Money".
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A game engine based application for visualising and analysing environmental spatiotemporal mobile sensor data in an urban contextHelbig, Carolin, Becker, Anna Maria, Masson, Torsten, Mohamdeen, Abdelrhman, Sen, Özgür Ozan, Schlink, Uwe 14 March 2024 (has links)
Climate change and the high proportion of private motorised transport leads to
a high exposure of the urban population to environmental stressors such as
particulate matter, nitrogen oxides, noise, and heat. The few fixed measuring
stations for these stressors do not provide information on how they are
distributed throughout the urban area and what influence the local urban
structure has on hot and cold spots of pollution. In the measurement
campaign “UmweltTracker” with 95 participants (cyclists, pedestrians), data
on the stressors were collected via mobile sensors. The aim was to design
and implement an application to analyse the heterogeneous data sets. In this
paper we present a prototype of a visualisation and analysis application based
on the Unity Game Engine, which allowed us to explore and analyse the
collected data sets and to present them on a PC as well as in a VR
environment. With the application we were able to show the influence of
local urban structures as well as the impact of the time of day on the
measured values. With the help of the application, outliers could be
identified and the underlying causes could be investigated. The application
was used in analysis sessions as well as a workshop with stakeholders.
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Modeling Large Scale OLAP ScenariosLehner, Wolfgang 11 January 2023 (has links)
In the recent past, different multidimensional data models were introduced to model OLAP (‘Online Analytical Processing’) scenarios. Design problems arise, when the modeled OLAP scenarios become very large and the dimensionality increases, which greatly decreases the support for an efficient ad-hoc data analysis process. Therefore, we extend the classical multidimensional model by grouping functionally dependent attributes within single dimensions, yielding in real orthogonal dimensions, which are easy to create and to maintain on schema design level. During the multidimensional data analysis phase, this technique yields in nested data cubes reflecting an intuitive two-step navigation process: classification-oriented ‘drill-down’/ ‘roll-up’ and description-oriented‘split’/ ‘merge’ operators on data cubes. Thus, the proposed Nested Multidimensional Data Model provides great modeling flexibility during the schema design phase and application-oriented restrictiveness during the data analysis phase.
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Using Semantics for Query Derivability in Data Warehouse ApplicationsAlbrecht, J., Hümmer, W., Lehner, Wolfgang, Schlesinger, L. 12 January 2023 (has links)
Materialized summary tables and cached query results are frequently used for the optimization of aggregate queries in a data warehouse. Query rewriting techniques are incorporated into database systems to use those materialized views and thus avoid accessing the possibly huge raw data. A rewriting is only possible if the query is derivable from these views. Several approaches can be found in the literature to check the derivability and find query rewritings. However, most algorithms either find rewritings only in very restricted cases or in complex cases which rarely occur in data warehouse environments. The specific application scenario of a data warehouse with its multidimensional perspective allows the consideration of much more semantic information, e.g. structural dependencies within the dimension hierarchies and different characteristics of measures. The motivation of this article is to use this information to present simple conditions for derivability in a large number of relevant cases which go beyond previous approaches.
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A Decathlon in Multidimensional Modeling: Open Issues and Some SolutionsHümmer, W., Lehner, W., Bauer, A., Schlesinger, L. 12 January 2023 (has links)
The concept of multidimensional modeling has proven extremely successful in the area of Online Analytical Processing (OLAP) as one of many applications running on top of a data warehouse installation. Although many different modeling techniques expressed in extended multidimensional data models were proposed in the recent past, we feel that many hot issues are not properly reflected. In this paper we address ten common problems reaching from defects within dimensional structures over multidimensional structures to new analytical requirements and more.
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Set-Derivability of Multidimensional AggregatesAlbrecht, J., Günzel, H., Lehner, Wolfgang 12 January 2023 (has links)
A common optimization technique in data warehouse environments is the use of materialized aggregates. Aggregate processing becomes complex, if partitions of aggregates or queries are materialized and reused later. Most problematic are the implication problems regarding the restriction predicates. We show that in the presence of hierarchies in a multidimensional environment an efficient algorithm can be given to construct - or to derive - an aggregate from one or more overlapping materialized aggregate partitions (set-derivability).
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The ecological and economic advantages of carbon reinforced concrete—Using the C³ result house CUBE especially the BOX value chain as an exampleTietze, Matthias, Kirmse, Susanne, Kahnt, Alexander, Schladitz, Frank, Curbach, Manfred 18 April 2024 (has links)
Against the background of global warming and the associated need to drastically reduce energy and resource consumption, action must also be taken in the building sector. Resource-efficient construction methods must be used that nevertheless allow the increasing construction tasks in areas such as infrastructure and housing to continue to be fulfilled. In order to successfully introduce a new construction method to the market, the aspects of recyclability and economic efficiency are essential, in addition to important government requirements for climate neutrality and technical performance. Above all, the economic viability, that is, the economic advantageousness, as well as its simple applicability compared to competing systems, decides on the success and widespread use of a new technology. Carbon reinforced concrete, with its outstanding technical properties and simultaneous material efficiency, is an important building block toward climate neutrality in the construction industry. It is a promising technology that still has to prove its economic advantages and robust applicability under market conditions. In addition to the infrastructure sector, there is great potential in the area of housing creation, which needs to be tapped for carbon reinforced concrete. For this challenge, it is necessary to design a competitive value chain that allows the realization of marketable products in mass production on existing plant technology. The article gives a short overview of the economic and ecological status quo in the field of prefabricated construction with carbon concrete, using the example of the C3-result building CUBE. In particular, the CUBE-BOX, which is made of prefabricated and semi-prefabricated parts, is examined in more detail and the carbon reinforced concrete components used are compared with classic reinforced concrete constructions in terms of sustainability. In this context, the conceivable global climate protection contribution of the carbon reinforced concrete construction method is forecast based on potential market segments.
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An XML-based Multidimensional Data Exchange Study / 以XML為基礎之多維度資料交換之研究王容, Wang, Jung Unknown Date (has links)
在全球化趨勢與Internet帶動速度競爭的影響下,現今的企業經常採取將旗下部門分散佈署於各地,或者和位於不同地區的公司進行合併結盟的策略,藉以提昇其競爭力與市場反應能力。由於地理位置分散的結果,這類企業當中通常存在著許多不同的資料倉儲系統;為了充分支援管理決策的需求,這些不同的資料倉儲當中的資料必須能夠進行交換與整合,因此需要有一套開放且獨立的資料交換標準,俾能經由Internet在不同的資料倉儲間交換多維度資料。然而目前所知的跨資料倉儲之資料交換解決方案多侷限於逐列資料轉換或是以純文字檔案格式進行資料轉移的方式,這些方式除缺乏效率外亦不夠系統化。在本篇研究中,將探討多維度資料交換的議題,並發展一個以XML為基礎的多維度資料交換模式。本研究並提出一個基於學名結構的方法,以此方法發展一套單一的標準交換格式,並促成分散各地的資料倉儲間形成多對多的系統化映對模式。以本研究所發展之多維度資料模式與XML資料模式間的轉換模式為基礎,並輔以本研究所提出之多維度中介資料管理功能,可形成在網路上通用且以XML為基礎的多維度資料交換過程,並能兼顧效率與品質。本研究並開發一套雛型系統,以XML為基礎來實作多維度資料交換,藉資證明此多維度資料交換模式之可行性,並顯示經由中介資料之輔助可促使多維度資料交換過程更加系統化且更富效率。 / Motivated by the globalization trend and Internet speed competition, enterprise nowadays often divides into many departments or organizations or even merges with other companies that located in different regions to bring up the competency and reaction ability. As a result, there are a number of data warehouse systems in a geographically-distributed enterprise. To meet the distributed decision-making requirements, the data in different data warehouses is addressed to enable data exchange and integration. Therefore, an open, vendor-independent, and efficient data exchange standard to transfer data between data warehouses over the Internet is an important issue. However, current solutions for cross-warehouse data exchange employ only approaches either based on records or transferring plain-text files, which are neither adequate nor efficient. In this research, issues on multidimensional data exchange are studied and an XML-based Multidimensional Data Exchange Model is developed. In addition, a generic-construct-based approach is proposed to enable many-to-many systematic mapping between distributed data warehouses, introducing a consistent and unique standard exchange format. Based on the transformation model we develop between multidimensional data model and XML data model, and enhanced by the multidimensional metadata management function proposed in this research, a general-purpose XML-based multidimensional data exchange process over web is facilitated efficiently and improved in quality. Moreover, we develop an XML-based prototype system to exchange multidimensional data, which shows that the proposed multidimensional data exchange model is feasible, and the multidimensional data exchange process is more systematic and efficient using metadata.
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Algebraické křivky v historii a ve škole / Algebraic curves in history and schoolFabián, Tomáš January 2016 (has links)
TITLE: Agebraic Curves in History and School AUTHOR: Bc. Tomáš Fabián DEPARTMENT: The Department of mathematics and teaching of mathematics SUPERVISOR: prof. RNDr. Ladislav Kvasz, Dr. ABSTRACT: The thesis includes a series of exercises for senior high school students and the first year of university students. In these exercises, students will increase their knowledge about conics, especially how to draw them. Furthermore, students can learn about two unfamiliar curves: Conchoid and Quadratrix. All these curves are afterwards used for solving other problems - some Apollonius's problems, Three impossible constructions etc. Most of the construction is done in GeoGebra software. All the tasks are designed for students to learn how to work with this software. The subject discussed is put into historical context, and therefore the exercises are provided with historical commentary. The thesis also includes didactic notes, important or interesting solutions of exercises, possible issues, mistakes and another relevant notes. KEYWORDS: conic, circle, ellipse, parabola, hyperbole, conchoid, quadratrix, trisecting an angle, squaring the circle, rectification of the circle, doubling a cube, Apollonius's problem, GeoGebra
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