Sustainable development requires measures to decrease energy consumption and to avoid any harmful impact on the environment. In recent years, a lot of research has been focused on designing energy systems by emulating the natural ones. This can be regarded as a novel way to support the transformation to sustainable energy systems. The initial step in forming energy systems of thus type, by emulating the ecosystem approach, is the development of a model for rendering the current situation. To contribute to the solution of this problem, an ecosystem model combining the analysis, optimisation and simulation modules has been developed as part of this study. The commonly used models for energy systems are good predictors of the general energy dynamics and structures; however, they can be inadequate when it comes to describing or predicting the complex phenomena within energy systems, such as the large number of parameters, the many end-users, the potential of the technologies, the assessment of the various environmental impacts and the variety of resources. With the implementation of the ecosystem model there is further expanding of the knowledge of an advanced, self-organising methodology integrated within the model’s operation by emulating the natural system dynamics. The ecosystem model could become a valuable tool for developing sustainable energy systems, and allowing the development of the most suitable and sustainable energy system based on the local availability of energy sources.
COBISS.SI-ID: 29437991
In order to measure the extent to which the distribution of workload between actors in the network can be equalized, a degree-weighted measure for a balanced workload based on betweenness centrality is introduced. The goal of this study is to determine the extremal values of the introduced measure, as well as the graph structures where the extremal values are attained. Several real world networks were used for evaluation of the new invariant. The obtained results are used for statistical comparison with standard measures of centrality to demonstrate validity of the introduced measure.
COBISS.SI-ID: 28956967
Obstacle detection plays an important role in unmanned surface vehicles (USVs). The USVs operate in a highly diverse environments in which an obstacle may be a floating piece of wood, a scuba diver, a pier, or a part of a shoreline, which presents a significant challenge to continuous detection from images taken on board. This paper addresses the problem of online detection by constrained, unsupervised segmentation. To this end, a new graphical model is proposed that affords a fast and continuous obstacle image-map estimation from a single video stream captured on board a USV. The model accounts for the semantic structure of marine environment as observed from USV by imposing weak structural constraints. A Markov random field framework is adopted and a highly efficient algorithm for simultaneous optimization of model parameters and segmentation mask estimation is derived. Our approach does not require computationally intensive extraction of texture features and comfortably runs in real time. The algorithm is tested on a new, challenging, dataset for segmentation, and obstacle detection in marine environments, which is the largest annotated dataset of its kind. Results on this dataset show that our model outperforms the related approaches, while requiring a fraction of computational effort.
COBISS.SI-ID: 1536310979
The design optimization of an axial flux permanent magnet synchronous machine with a coreless stator and double external rotor is accomplished by using evolutionary optimization with a genetic algorithm and an analytical evaluation of objective functions. On the basis of eight variable geometry parameters, five objective functions are optimized in order to determine the maximum volume torque density and weight torque density, the minimum volume and weight of permanent magnets per Newton-meter, and the minimum machine price per Newton-meter. Based on the geometric parameters for minimum machine price per Newton-meter, a prototype is built for the rated torque. Optimized and analytically evaluated machine characteristics are validated with a finite-element method (FEM) and the measurements of a prototype. Evolutionary optimization with the analytical evaluation of objective functions significantly shortens the computational time required for design optimization in comparison with the FEM.
COBISS.SI-ID: 84086785
The paper deals with the security problems of scan design and investigates currently proposed solutions. A solution based on data encryption to protect the data in scan chains is discussed and problems related to the block-based encoding are outlined. Next, security extension for IEEE Std. 1149.1 providing a locking mechanism is analysed. The mechanism prevents unauthorised users to interfere via test bus with the system normal operation. Possible attack scenario is considered and the probabilities of successful attack within a given time interval are calculated for different lengths of the Lock register. The paper concludes with the description of current work focused on improvements the security of the locking mechanism, in particular by using simplified public key infrastructure.
COBISS.SI-ID: 29573927