Following some recent works of Witten, we explore topological non-linear sigma models (TSM). W e construct 2-D topological gravity which is then coupled to the TSM resulting in a topological bosonic string theory. This theory has a nontachyonic vacuum and can be formulated on any even dimensional target manifold which admits some non-trivial topology. It is then shown that the metric independen...

Abstmct Our success in deploying the illusion of infinite stomge to applications rests in the use of database tebhnology. Tht3 paper presents the support for transactions in the ADSTAR Dhtributed Stomge Manager, (A DSiU) system. For a user, ADSM offers a backup and archive service in a heterogeneous cliint-server environment. It also operates as a file migratton mposito~ in some Unix environmen...

In this paper we introduce a page-based Lazy Release Consistency protocol called ADSM that constantly and efficiently adapts to the applications' sharing patterns. Adaptation in ADSM is based on our dynamic categorization of the type of sharing experienced by each page. Pages can be categorized as falsely-shared, migratory, or producer/consumer(s). Migratory and producer/consumer(s) pages are m...

A multidimensional gravitational model with several scalar fields, fields of forms and cosmological constant is considered. When scalar fields are constant and composite p-brane monopole-like ansatz for the fields of forms is adopted, a wide class of solutions on product of n + 1 Einstein spaces is obtained. These solutions are composite p-brane generalizations of the Freund-Rubin solution. Som...

In-situ data of optically active water constituents and their inherent optical properties were collected during a four-week field cruise in Namibian coastal waters and Atlantic Ocean to validate MERIS geophysical products. The in-situ data set covered a wide range of different water types from very productive coastal upwelling waters to clear open ocean waters where the water color varied from ...

The newly finished ESA project MERIS Lakes included activity in Lake Victoria to show the potensial for monitoring this eutrophic African Lake. In this study an evaluation of how different processors perform in Lake Victoria. Lack of proper validation data makes it only possible to have a preliminary assessment of the performance of the product algal_2, suspended material and the signal depth, ...

In many real world problems, system parameters or model coefficients may be bounded between lower and upper bounds due to a variety of uncertainties. Over the past decades, intensive research efforts have focused on interval linear programming (ILP) to tackle such uncertainties. As one of the most popular methods for solving ILP problems, Two-Step Method (TSM, proposed by Huang et al. in 1995) ...

A novel adaptive dynamic sliding mode (ADSM) fault-tolerant control (FTC) methodology is developed for near space vehicle attitude control systems with actuator faults in this paper. The proposed ADSM approach combines dynamic sliding mode with adaptive control strategies that can make the systems stable and accurately track the desired signals in the presence of external disturbances, model pa...

Recently a “Bag-of-Audio-Words” approach was proposed [1] for the combination of lexical features with audio clips in a multimodal semantic representation, i.e., an Audio Distributional Semantic Model (ADSM). An important step towards the creation of ADSMs is the estimation of the semantic distance between clips in the acoustic space, which is especially challenging given the diversity of audio...