684 research outputs found
A sequential semidefinite programming method and an application in passive reduced-order modeling
We consider the solution of nonlinear programs with nonlinear
semidefiniteness constraints. The need for an efficient exploitation of the
cone of positive semidefinite matrices makes the solution of such nonlinear
semidefinite programs more complicated than the solution of standard nonlinear
programs. In particular, a suitable symmetrization procedure needs to be chosen
for the linearization of the complementarity condition. The choice of the
symmetrization procedure can be shifted in a very natural way to certain linear
semidefinite subproblems, and can thus be reduced to a well-studied problem.
The resulting sequential semidefinite programming (SSP) method is a
generalization of the well-known SQP method for standard nonlinear programs. We
present a sensitivity result for nonlinear semidefinite programs, and then
based on this result, we give a self-contained proof of local quadratic
convergence of the SSP method. We also describe a class of nonlinear
semidefinite programs that arise in passive reduced-order modeling, and we
report results of some numerical experiments with the SSP method applied to
problems in that class
Principales publications du Service Hydrologique de l'ORSTOM, année 1974 = main works of the Hydrological Service of ORSTOM, year 1974
Principales publications du Service Hydrologique de l'ORSTOM = main works of the Hydrological Service of ORSTOM
Henri Temianka Correspondence; (jarre)
This collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/3884/thumbnail.jp
Principales publications du Service Hydrologique de l'ORSTOM, année 1976 = main works of the Hydrological Service of ORSTOM, year 1976
Urbanity as Diversity: On the architectural conditions of urban life
Urbanity is a frequently but often vaguely used notion in both urban design and social science. My intention is to contribute conceptually and programmatically to attaining a richer urbanity by analysing its traditional character and some literature treating it, such as Jane Jacobs’s classical work. The assumption behind my conceptual clarification and conceptual development is thus that the current confusion of ideas not only hampers informed public and academic discussion on planning objectives but also adversely affects its results, even in cities with a strong planning organisation, such as Helsinki. In elucidating the concept, I shall distinguish between architectural and social urbanity. One may identify a rudimentary variant of the former centring on efficient land-use and (rough) functional synergy. A more sophisticated conception, supporting a socially well-working environment, requires an account in design terms including notions such as efficiency and synergy but also the key concept of diversity, vital for urbanity in a social sense. Complications still appear when concretising the notion: different types of diversity may conflict, there may be competing diversity-related values, and diversity may degenerate into chaos or meaningless discord. Scalemay affect the relative benefits of diversity and homogeneity. To clear up some of the puzzles, I shall present a minimal but strict interpretation of architectural urbanity building on prototypical traits of the traditional European city and compare the account especially with Jacobs’s discussion. Key elements of such prototypical urbanity are the public street space delimited by perimeter blocks, communicating ground floors and small building units. While the ideal-typical character of the description entails some normativity of sorts in picking up features considered essential, it should be intuitive enough not to be easily dismissed. Nonetheless, if genuine urbanity is sought for, the account, once accepted, takes on a more clearly normative role, shifting the burden of proof to anyone suggesting solutions deviating from it. This also holds for Jacobs’s ideas, if not refuted. Thus, if one acknowledges her prescriptions as scientifically rational and the nature of such knowledge as professionally binding, architectural solutions contradicting it are unacceptable, even when resulting from apparently diversity-generating artistic freedom. Respecting the guiding function of analytical, theoretical and empirical arguments is important not to let tangible interests and strictly sanctioned technical, economic and juridical requirements alone condition urban design and planning. However, if social scientists, too, disregard or deny the value of such knowledge, important questions will remain unexplored. Among them are architectural urbanity as a precondition for social urbanity and mechanisms impeding its realisation. Concerning the procedural issue of how to generate architectural diversity and urbanity, Jacobs sometimescomes close to rejecting planning, trusting spontaneous order to emerge from interaction and free enterprise. Alternatively, however, detailed steering might have the desired effect. A presupposition for successfully using available political or organisational means for producing a truly urban and socially well-working city, is a clear comprehension of the ends pursued. The treatment tries to contribute to such an understanding. However, the task remains of more unambiguously connecting architectural to social urbanity.Peer reviewe
Principales publications du Service Hydrologique de l'ORSTOM, année 1975 = main works of the Hydrological Service of ORSTOM, year 1975
Alien Registration- St Jarre, Leo (Fort Fairfield, Aroostook County)
https://digitalmaine.com/alien_docs/35916/thumbnail.jp
Alien Registration- St Jarre, Alcide (Fort Fairfield, Aroostook County)
https://digitalmaine.com/alien_docs/35915/thumbnail.jp
Information gain versus state disturbance for a single qubit
The trade-off between the information gain and the state disturbance is
derived for quantum operations on a single qubit prepared in a uniformly
distributed pure state. The derivation is valid for a class of measures
quantifying the state disturbance and the information gain which satisfy
certain invariance conditions. This class includes in particular the Shannon
entropy versus the operation fidelity. The central role in the derivation is
played by efficient quantum operations, which leave the system in a pure output
state for any measurement outcome. It is pointed out that the optimality of
efficient quantum operations among those inducing a given operator-valued
measure is related to Davies' characterization of convex invariant functions on
hermitian operators.Comment: 17 pages, LaTeX, osid.sty. Substantially expanded and generalize
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