Search results for "System model"
showing 7 items of 87 documents
Chaos and its Degradation-Promoting-Based Control in an Antithetic Integral Feedback Circuit
2022
This letter deals with a novel variant of antithetic integral feedback controller (AIFC) motifs which can feature robust perfect adaptation, a pervasive (desired) ability in natural (synthetic) biomolecular circuits, when coupled with a wide class of process networks to be regulated. Using the separation of timescales in the proposed kind of AIFC, here we find a reducedorder controller that captures the governing slow part of the original solutions under suitable assumptions. Inspired by R(ossler systems, we then make use of such a simpler controller to show that the antithetic circuit can exhibit chaotic behaviors with strange attractors, where the bifurcation from a homeostatic state to c…
The balanced digitalization and digital security : Case of regional authorities
2019
The emerging digital infrastructure enables the public authorities to shape their processes and to create attractive digital services for the citizens and the business actors. The public processes, services and infrastructure, however, engage with global and local public and private digital infrastructure and service providers. The complex comprehensiveness of the digital infrastructure and the services challenges the public authorities and create new types of security risks. The achieving of the benefits of the digitalization of public processes and services without increasing security risks requires the adopting of novel approaches to digital security. The paper refers to a framework that…
Mapping of the human visual cortex using image-guided transcranial magnetic stimulation
2002
We describe a protocol using transcranial magnetic stimulation (TMS) to systematically map the visual sensations induced by focal and non-invasive stimulation of the human occipital cortex. TMS is applied with a figure of eight coil to 28 positions arranged in a 2x2-cm grid over the occipital area. A digitizing tablet connected to a PC computer running customized software, and audio and video recording are used for detailed and accurate data collection and analysis of evoked phosphenes. A frameless image-guided neuronavigational device is used to describe the position of the actual sites of the stimulation coils relative to the cortical surface. Our results show that TMS is able to elicit p…
Grid-Following and Grid-Forming MODELS in ATP-EMTP for Power Systems Simulation
2022
The paper presents the models of grid-following and grid-forming converters in the software ATP-EMTP for power systems simulation. The models are developed using the MODELS language, they are described in details discussing all issues and aspects related to the implementation, and they are also shared as open source models. The models are validated with a simulation-based approach, comparing the results with the models developed in MATLAB/Simulink and in NEPLAN, considering both the phasor RMS and EMT time domains, and thus performing a comprehensive cross-platform and cross-domain validation. In line with the spirit of the ATP software and community, the models of grid-following and grid-f…
Time-Dependent Multiple Depot Vehicle Routing Problem on Megapolis Network under Wardrop's Traffic Flow Assignment
2018
In this work multiple depot vehicle routing problem is considered in case of variable travel times between nodes on a metropolis network. This variant of the classic multiple depot vehicle routing problem is motivated by the fact that in urban contexts variable traffic conditions play an essential role and can not be ignored in order to perform a realistic optimization. Time-travel matrices corresponding to each period of planning horizon were formed by solving the traffic assignment problem in conjunction with shortest path problem. Routing problem instances include from 20 to 100 customers randomly chosen from a road network of Saint-Petersburg. The results demonstrate that taking into ac…
Learning and using English and Swedish beyond the classroom : activity systems of six upper secondary school students
2012
Tämän tutkimuksen tarkoituksena oli katsoa englannin ja ruotsin oppimista koulun ulkopuolella toiminnan teorian ja erityisesti Engeströmin (1987, 1999) toimintajärjestelmämallin näkökulmasta, josta aihetta ei ole aiemmin lähestytty. Tutkimus vastaa seuraaviin kysymyksiin: 1) Ovatko abiturientit enemmän kielenkäyttäjiä vai -oppijoita englannissa ja ruotsissa koulun ulkopuolella? 2) Millaisia eroja ja yhtäläisyyksiä heidän toiminnassaan on englannissa ja ruotsissa? 3) Mitkä tekijät selittävät aktiivisuutta ja passiivisuutta? Tutkimus on toteutettu tapaustutkimuksena. Tutkimusaineistona on kuusi puolistrukturoitua haastattelua. Haastateltavat ovat 18-vuotiaita lukion kolmannen vuosikurssin opi…
Dynamic Modeling for Environmental Processes: A Case Study of Lake Engure
2014
Abstract This focus of the study was on system dynamic models that could be useful for modelling environmental processes in Lake Engure. The paper considers the system dynamic model development principles, the most important elements and structure. The aim of the study was to describe possible methods of ecosystem process modelling that allow to represent the actual state of ecosystems and provide opportunities to predict further processes. The methods of ecosystem modelling considered in the paper reveal interactive factors of anthropogenic and environmental processes that influence changes in ecosystems. System dynamic models indicate not only interactions between various factors in the e…