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- Winter, Johannes, et al.
(författare)
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Charge transfer in alkali-metal-doped polymeric fullerenes
- 1996
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 54, s. 17486-17492
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Tidskriftsartikel (refereegranskat)abstract
- We present room-temperature Raman measurements of pressure-polymerized C60 and compare them with the spectra of RbC60 in the orthorhombic phase. Although both materials were prepared according to two completely different routes the spectra show a surprising similarity with respect to mode positions and line splitting. We concluded from this that both materials, the uncharged pressure-polymerized C60 and the rubidium-doped orthorhombic compound, have the same overall structure and the AC60 compounds can be considered as the doped species of the C60, polymerized using moderate low pressure and high temperatures. From a detailed comparison between both spectra mode shifting and line broadening as a consequence of the charge transfer was determined and electron-phonon coupling constants were estimated for the high-frequency Hg(7) and Hg(8) modes. The low values for the coupling constants compared to the ones in the K3C60 can explain the lack of superconductivity in the AC60 compounds.
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| 2. |
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| 3. |
- Lundberg, Magnus, et al.
(författare)
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High-level modeling of switching activity with application to low-power DSP system synthesis
- 1999
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Ingår i: Proceedings / 1999 IEEE International Conference on Acoustics, Speech, and Signal Processing. - Piscataway, NJ : IEEE Communications Society. - 0780350413 ; , s. 1877-1880, s. 1877-1880
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Konferensbidrag (refereegranskat)abstract
- We address the issue of high-level synthesis of low-power digital signal processing (DSP) systems by proposing switching activity models. In particular, we present a technology independent hierarchical scheme to compare relative power performance of two competing DSP systems. The basic building blocks considered for such system are a full-adder and a one-bit delay. Estimates of switching activity at the output of these building blocks is used to model the activity in different architectural primitives used for building DSP systems. This method is very fast and simple and simulations show accuracy within 4% of extensive bit-level simulations. Therefore, it can easily be integrated into current communications/DSP CAD tools for low-power applications. The models show that the choice of multiplier/multiplicand is important when using array multipliers in a data-path. If the input signal with smaller variance is chosen as the as the multiplicand, up to 20% savings in switching activity can be achieved. This observation is verified by analog simulation
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| 4. |
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| 5. |
- Gellerstedt, Sten
(författare)
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Arbete och hälsa vid skogsarbete: En multivariat studie av huggare och maskinförare
- 1993
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with a model of the influence of work, of individual capacities and on how work affects the individual. The studies are connected to the "work science" tradition. Manual and mechanized forest work with their physical and mental loads are described and analysed. The particular problems that field studies involve are discussed. In conclusion a vision of a future forest work is presented.
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| 6. |
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| 7. |
- Nordlander, Johan, 1962
(författare)
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Reactive Objects and Functional Programming
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The construction of robust distributed and interactive software is still a challenging task, despite the recent popularity-increase for languages that take advanced programming concepts into the mainstream. Several problematic areas can be identified: most languages require the reactivity of a system to be manually upheld by careful avoidance of blocking operations; mathematical values often need to be encoded in terms of stateful objects or vice versa; concurrency is particularly tricky in conjunction with encapsulated software components; and static type safety is often compromised because of the lack of simultaneous support for both subtyping and polymorphism. This thesis presents a programming language, O'Haskell, that has been consciously designed with these considerations in mind. O'Haskell is defined by conservatively extending the purely functional language Haskell with the following features: A central structuring mechanism based on reactive objects, which unify the notions of objects and concurrent processes. Reactive objects are asynchronous, state-encapsulating servers whose purpose is to react to input messages; they cannot actively block execution or selectively filter their sources of input. A monadic layer of object-based computational effects, which clearly separates stateful objects from stateless values. Apart from higher-order functions and recursive data structures, the latter notion also includes first-class commands, object templates, and methods. A safe, polymorphic type system with declared record and datatype subtyping, supported by a powerful partial type inference algorithm. It is claimed that these features make O'Haskell especially well-adapted for the task of modern software construction. The thesis presents O'Haskell from both a practical and a theoretical perspective. The practical contributions are a full implementation of the language, a number of non-trivial programming examples that illustrate the merits of reactive objects in a realistic context, and several reusable programming methods for such applications as graphical user interfaces, embedded controllers, and network protocols. The theoretical results serve to substantiate the informal claim made regarding usability, and include a provably sound polymorphic subtyping system, soundness and partial completeness for the inference algorithm, a formal dynamic semantics, and a result that characterizes the conservative extension of a purely functional language with state and concurrency.
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