Ten-dimensional superstring theory (or the conjectured nonperturbative Mtheory in eleven dimensions) is the most promising candidate for a consistent quantum theory of gravity capable of unifying all known forces of nature. An important question concerning these fundamental theories is how they compactify to lower dimensions and how to obtain a real four dimensional world? In this dissertation we present new avenues for M/string theory to reduce to lower dimensions as well as to four dimensions. For example, we show that by performing a generalized Kaluza-Klein IR reduction on the low-energy field theory of the heterotic string, the resulting lower dimensional theory compactifies spontaneously on S3 to give rise to (Minkowski)6 spacetime. Furthermore, a generalized reduction of M-theory on K3 × IR compacti- fies spontaneously on S2 to give rise to a (Minkowski)4 spacetime. The generalized Kaluza-Klein reduction gauges the Cremmer-Julia type global symmetry and the homogeneous rescaling symmetry of the supergravity equations of motion by giving the higher dimensional fields an additional dependence on the circle coordinate. We apply the generalized reduction scheme to half-maximal supergravities which are obtained from the heterotic string (or the NS-NS sector of the type-II string) compactified on a (10 − D)-dimensional torus truncated to the pure supergravity multiplet. This gives rise to new gauged supergravities in diverse dimensions with supersymmetric Minkowski × sphere vacua.Since two large extra dimensions have received much attention recently, we make a detailed study of the gauged D = 6, N = (1, 1) supergravity. In particular, we show that this theory allows for a consistent sphere reduction on S2 to give rise to D = 4, N = 2 supergravity coupled to a vector multiplet which can further be truncated to N = 1 supergravity with a chiral multiplet. We also investigate pp-waves in AdS backgrounds, i.e. pp-waves as solutions of gauged supergravities with AdS vacua. These solutions generically preserve 1 4 of the supersymmetry. We demonstrate supernumerary supersymmetries for both purely gravitational pp-waves and pp-waves supported by fields strengths. These new backgrounds provide interesting novel features of the supersymmetry enhancement for the dual conformal field theory in the infinite-momentum frame.

In the course of attempting to prepare 3,6-bis(hydroxy-methyl)-s-tetrazine via the reduction of 3,6-bis(carboxy)-s-tetrazine with lithium aluminum hydride, it became apparent that the tetrazine ring was cleaved.

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The lecture recital was given on July 2, 1984. The Megalith Trilogy was performed following a lecture which examined the internal structure of the work. The main body of the lecture focused on motivic and tonal considerations and included motivic and pitch reductions of the three movements. In addition to the lecture recital three other public solo recitals were performed. The four programs were recorded on magnetic tape and are filed with the written version of the lecture as a part of the dissertation.

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / The system architecture of an onboard FTI-System is specifically designed to fulfil highly demanding flight test requirements. Since these flight test requirements are steadily increasing with the growing complexity of test aircraft and mission systems, a corresponding improvement in the performance of the FTI-Systems is mandatory to satisfy those flight test demands. In addition, the individual test flights have to provide the maximum of flight test data obtainable in order to improve test efficiency and to cut project costs. Increased performance, miniaturisation, more reduced design and installation costs are the challenges for future system architectures. The developments of commercial and consumer electronics have an increasing influence on the layout of FTI-Systems.

Title: Search problems and search for collisions in hash functions Author: Samuel Čarnoký Department: The Department of Algebra Supervisor: prof. RNDr. Jan Krajíček, DrSc. Supervisor's e-mail address: krajicek@karlin.mff.cuni.cz Abstract: Central points of this work are NP search problems and the existence of reductions amog them in the relativised world. Absolute separation would separate N from NP. In particular, we talk about the problem of finding collisions in hash functions that must exist due to the famous pigeonhole principle. We present a brief introduction into the topic, we define various NP search problems and recall reductions and separations. Reduction of weak version of PHP to a problem of finding a homogeneous subgraph is described and our own results are presented in the form of reduction of another variant of PHP to a problem related to finding paths in a graph. We talk about reducing the task of finding collisions in multiple functions into finding a collision in one function. Keywords: NP search, reductions, pigeonhole principle, oracles

Upon dimensional reduction, certain supergravity theories exhibit symmetries otherwise undetected, called hidden symmetries. Not only do these symmetries teach us about the structure of the corresponding theories but moreover they provide methods to construct black hole solutions. In this thesis, we study the hidden symmetries of supergravity theories of particular interest and how these help constructing black hole solutions in dimensions D>4. We focus on three representative cases that are the symmetries appearing upon dimensional reduction to three, two and one dimensions. They are respectively described by finite, affine and hyperbolic algebras. In the first two cases, we develop and apply solution generating techniques. The first part of this thesis introduces the background concepts. We start with an introduction to black holes and other black objects in dimensions D>4. We present their subtleties, the known solutions and the conjectured ones. We insist on stationary axisymmetric solutions of vacuum and to the corresponding solution generating technique. The next chapter gives an introduction to Kac-Moody algebras. These indeed play a central role in this thesis as the symmetries appearing in three, two and one dimensions are described by three types of Kac-Moody algebras called respectively finite, affine and hyperbolic. In the second part, we first review the notion of dimensional reductions and how the hidden symmetries can be uncovered. The rest of the thesis contains three applications of these hidden symmetries. The first two concern five-dimensional minimal supergravity. Upon dimensional reduction to three dimensions, this theory exhibits a symmetry under the exceptional finite Kac-Moody algebra g2. This 14-dimensional algebra is the smallest exceptional finite Kac-Moody algebra. We use this duality to generate solutions while focussing mainly on black strings. After reduction to two dimensions, the symmetry becomes infinite-dimensional and is described by the affine extension of g2. Moreover, the two-dimensional theory is integrable, which allows us to develop another type of solution generating technique, hitherto applied only to vacuum gravity. In this work we generalize it to a case with matter fields. Finally, the notion of dimensional reduction to one dimension provides the necessary intuition for the conjecture of an algebraic formulation of M-theory, candidate to the unification of all interactions, based on the hyperbolic Kac-Moody algebra e10. In the last chapter of this thesis, we study an aspect of this correspondence, namely the e10 symmetry of massive type IIA supergravity in ten dimensions. / On sait depuis longtemps que par un processus appelé réduction dimensionnelle, on peut faire apparaître dans certaines théories de gravitation des symétries autrement indétectées. On les appelle des symétries cachées. La mise en évidence de ces symétries non seulement nous informe sur la structure de ces théories, mais de plus elle permet d'élaborer des méthodes de construction de solutions de trous noirs. Dans cette thèse, nous étudions les symétries cachées de certaines théories de supergravité en dimensions supérieures à quatre. Nous nous concentrons sur trois cas représentatifs que sont les symétries apparaissant après réduction à trois, deux et une dimensions. Dans les cas des symétries apparaissant à trois et à deux dimensions nous développons et appliquons des méthodes de construction de solutions. La première partie introduit les concepts préliminaires. Nous commençons par une introduction aux trous noirs et autres objets noirs en dimensions supérieures à quatre. Nous en présentons les subtilités, les solutions connues à ce jour et celles qui ne sont encore que conjecturées. Nous insistons particulièrement sur les solutions stationnaires à symétrie axiale dans le vide et à la méthode de construction de solutions correspondante. Le chapitre suivant présente une introduction aux algèbres de Kac-Moody. Celles-ci jouent en effet un rôle central dans cette thèse puisque les symétries apparaissant à trois, deux et une dimensions sont décrites par trois types d'algèbres de Kac-Moody appelées respectivement finies, affines et hyperboliques. Dans la deuxième partie, nous rentrons dans le vif du sujet, en commençant par rappeler le principe des réductions dimensionnelles et la mise en évidence des différents types de symétries cachées. Les trois derniers chapitres contiennent ensuite trois applications de ces symétries cachées. Dans deux d'entre eux, nous nous concentrons sur la théorie de supergravité minimale à cinq dimensions. Après réduction à trois dimensions, cette théorie présente un symétrie cachée sous le groupe G2 qui, avec quatorze dimensions, est le plus petit des groupes de Lie exceptionnels. Nous utilisons cette dualité pour engendrer des solutions, en nous focalisant essentiellement sur les solutions de cordes noires. A deux dimensions, la symétrie est décrite par l'extension affine de G2. De plus, la théorie est alors complètement intégrable. Cela conduit à un autre type de méthode de construction de solutions, jusqu'alors uniquement appliquée à des théories dans le vide. Dans ce travail, nous la généralisons donc à un cas avec champs de matière. Enfin, la notion de réduction à une dimension fournit l'intuition d'une conjecture selon laquelle la théorie M, candidate à l'unification de toutes les interactions, pourrait être reformulée en une théorie basée sur l'algèbre de Kac-Moody hyperbolique e10. Dans le dernier chapitre de cette thèse, nous étudions un aspect de cette correspondance, à savoir, la symétrie sous e10 de la supergravité massive de type IIA à dix dimensions.

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This research aims to study the effects of organization downsizing programs on the staff in the field of electronic media. There used to be only three television networks in Taiwan, which were TTV, CTV, and CTS. Followed by the approval of the Cable Television Law in 1993, cable TV providers began to enter the market and sprout like mushrooms. A point worth noting is that Taiwan's fourth terrestrial TV station, FTV, officially founded and joined the market in 1997. Significant changes were then brought to Taiwan¡¦s media landscape. The advantages of the three original TV networks were disappearing and taken by the newly emerged cable TV stations. Thanks to the free market mechanism, the competition among news media has become even more and more intense over the last three or four years. A medium which has strong constitution appears to have better performance and is able to maintain certain market share; while those have weak constitutions would often suffer losses in business, in which the most serious are the three original terrestrial TV stations. It makes no exception for cable TV networks, either. Deficit occurs in many cable TV stations, such as CTI, ERA, USTV, STV and Global TV, whereas SET, TVBS, ETTV, and GTV could still obtain profits. The above factors show that downsizing in the field of electronic media must be carried out. The subjects of this research were a group of TV news reporters who have gone through organization downsizing. Interviews were designed to discover the reporters¡¦ perception, involvement, organizational identity and intention to continue in office in search of the best downsizing model. The results are as follows: (1) Downsizing programs have certain impact on staff. Organizations which encourage voluntary demission or retirement might hardly achieve its goal of downsizing in a short while, but survivors would relatively tend to be less likely to resign from office. On the contrary, when compulsory or semi-compulsory methods are used, survivors would be devastated or even muddle along. Such situation might even cause lots of survivors to quit. (2) Thetrimming of personal in electronic media, areusually due to unbalance of information, causing current employee¡¦s varies in working behavior and attitude, cause by age, experience and rank difference. It means that because of freer flow of information, employees that are higher age, more experience, and higher rank, are less affected in behavior and attitude, and more stable. On the other hand, employees that are lower age, less experience and work in the basic level, because of the lack of information, when personal trimming begins, they become more anxious and start quitting. (3)Having a comprehensive scheme, informing and making the employees involved in the whole decision making process, as well as engaging in appropriate dialogue would all increase the willingness of survivors to continue in office and weaken their tendency to resign. (4)Employees who agree with their organization's values and feel a strong sense of connection with their organization tend to be less likely to quit; while others would have stronger inclination to resign.

Energy security is probably one of the most challenging issues around the world. Therefore, the focus on methods of decreasing energy consumption and consequently its associated greenhouse gas (GHG) emissions is intensified by policy decision makers. Residential buildings are one of the potential sectors that can reduce its energy consumption in various ways, such as: improving thermal characteristics of the building, using more energy efficient appliances and using renewable energy resources. Among these methods, integration of solar technologies to buildings provides one of the substantial opportunities for reducing energy consumption and the associated GHG emissions in Canada’s residential sector. Therefore, this research work was conducted to assess the impact of solar technologies and solar technology integration strategies on the end-use energy consumption and the associated greenhouse gas (GHG) emissions in Canadian residential sector by using a new state-of-the-art end-use energy and GHG emissions model of the Canadian residential housing stock. The new Canadian residential end-use energy and emissions model that is used in this project incorporates a 17,000 house database developed using the latest data available from the Energuide for Houses database, Statistics Canada housing surveys, and other available housing databases, and utilizes an advanced building energy simulation program as its simulation engine. A new neural network methodology is incorporated into the model to estimate the socio-economic and demographic dependencies of the energy consumption of discretionary end-uses such as appliances, lighting and domestic hot water, while a new approach is used to incorporate occupancy, appliance, lighting and domestic hot water load profiles into the model. A new method is used to calculate the GHG emissions from electricity consumption used in the residential sector based on the actual electrical generation fuel mix and the marginal fuel used in each province as a function of time of the year. Each solar technology is added to the eligible houses to examine the interrelated effects of integrated solar technologies and practices on the housing stock. The objective is to conduct realistic assessments of the cost effectiveness, energy savings and GHG emission reduction benefits of integrated solar technologies for the entire Canadian housing stock (CHS) as well as for different regions, house type, and fuel types. The integrated solar technologies and practices that are assessed include passive solar with added thermal storage and motorized blinds, solar DHW system, and photovoltaic electricity and heat generation systems. This project provides a comprehensive techno-economic and emissions assessment of integrated solar technologies and practices, and will be useful for developing national and regional policies and strategies related with integrating solar energy into the residential sector.