Search results for "Markov"
showing 10 items of 628 documents
Markovica investīciju portfeļu izveide un analīze
2019
Investēšana akcijās ir ļoti sena un pazīstama investēšanas stratēģija un šī darba ietvaros tiek parādīts, kura investēšanas stratēģija veidojot efektīvu Markovica portfeli nodrošina vislabāko riska un ienesīguma attiecību. Maģistra darba mērķis ir, balstoties uz zinātniskās literatūras un uzņēmumu akcijas analīzi, izveidot trīs diversificētus un efektīvus akciju portfeļus pēc Markovica investīciju portfeļa stratēģijas (B. Grema, Dž. Piotroski un Dž. Grīnblata) un noteikt labāko portfeli pēc riska un ienesīguma attiecības. Darba autors veica B. Grema, Dž. Piotroski un Dž. Grīnblata stratēģiju izpēti un pēc tās atlasīja akcijas ieguldījumu portfelī. Analizējot katru stratēģiju un izvērtējot t…
Vērtspapīru portfeļa veidošana un pārvaldīšana
2015
Bаkаlаurа dаrbа mērķis ir, bаlstоtiеs uz zinātniskо litеrаtūru, арskаtīt vērtsрарīru vеidus, iераzītiеs аr роrtfеļа vеidоšаnаs nоsаcījumiеm un izvеidоt орtimālо vērstрарīru роrtfеli, аr sаmērīgо sаgаidāmо iеnеsīgumu un iеsрējаmо riskа раkāреs рrороrciju, kа аrī izdаrīt sеcinājumus un izstrādāt рriеkšlikumus šādа роrtfеļа sаstādīšаnаi un рārvаldīšаnаi. Dаrbа sākumā ir dеtаlizēti арrаkstīti vаirāku vērtsрарīru būtībа un tо īраtnībаs, kā аrī tо vērtībаs nоtеikšаnаs mеtоdеs. Рirmаjā nоdаļā аrī iеviеsts riskа jēdziеns un rаksturоtа riskа un iеnеsīgumа sаkаrībа. Turрinājumā dаrbа аutоrе арskаtа gаlvеnās vērtsрарīru аnаlīzеs mеtоdеs: fundаmеntālа un tеhniskā аnаlīzеs, kā аrī Mаrkоvicа tеоriju, kur…
Monte Carlo simulation of DNA electrophoresis
1989
This paper describes an attempt to study the electrophoresis mobility of a DNA molecule in a gel by means of a Monte Carlo simulation. We find that the electrophoresis mobility mu can be well described by the empirical equation mu v kappa 1/N + kappa 2E2 with N being the number of monomers of the model chain and E being the applied field. For small E the data can merge into the linear response result mu = kappa 1/N. The paper also discusses necessary extensions of the present approach.
A study on forecasting electricity production and consumption in smart cities and factories
2019
Abstract The electrical power sector must undergo a thorough metamorphosis to achieve the ambitious targets in greenhouse gas reduction set forth in the Paris Agreement of 2015. Reducing uncertainty about demand and, in case of renewable electricity generation, supply is important for the determination of spot electricity prices. In this work we propose and evaluate a context-based technique to anticipate the electricity production and consumption in buildings. We focus on a household with photovoltaics and energy storage system. We analyze the efficiency of Markov chains, stride predictors and also their combination into a hybrid predictor in modelling the evolution of electricity producti…
Control for Networked Control Systems with Time Delays and Packet Dropouts
2013
This paper is concerned with the control issue for a class of networked control systems (NCSs) with packet dropouts and time-varying delays. Firstly, the addressed NCS is modeled as a Markovian discrete-time switched system with two subsystems; by using the average dwell time method, a sufficient condition is obtained for the mean square exponential stability of the closed-loop NCS with a desired disturbance attenuation level. Then, the desired controller is obtained by solving a set of linear matrix inequalities (LMIs). Finally, a numerical example is given to illustrate the effectiveness of the proposed method.
H∞ control for two-dimensional Markovian jump systems with state-delays and defective mode information
2013
This paper investigates the problem ofℋ∞state-feedback control for a class of two-dimensional (2D) discrete-time Markovian jump linear time-delay systems with defective mode information. The mathematical model of the 2D system is established based on the well-known Fornasini-Marchesini local state-space model, and the defective mode information simultaneously consists of the exactly known, partially unknown, and uncertain transition probabilities. By carefully analyzing the features of the transition probability matrices, together with the convexification of uncertain domains, a newℋ∞performance analysis criterion for the underlying system is firstly derived, and then theℋ∞state-feedback co…
Comparison of different uncertainty techniques in urban stormwater quantity and quality modelling
2011
Abstract Urban drainage models are important tools used by both practitioners and scientists in the field of stormwater management. These models are often conceptual and usually require calibration using local datasets. The quantification of the uncertainty associated with the models is a must, although it is rarely practiced. The International Working Group on Data and Models, which works under the IWA/IAHR Joint Committee on Urban Drainage, has been working on the development of a framework for defining and assessing uncertainties in the field of urban drainage modelling. A part of that work is the assessment and comparison of different techniques generally used in the uncertainty assessm…
A dynamic channel access strategy for underlay cognitive radio networks: Markov modelling and performance evaluation
2015
Unlike in overlay cognitive radio networks, secondary users in underlay cognitive radio networks can access licensed spectrum even at the presence of a primary user, given that the interference caused by the secondary transmission is lower than a pre-specified threshold. Based on this underlay access principle, we propose in this paper a dynamic channel access strategy for multi-channel cognitive radio networks. Different from existing underlay access techniques, channel assembling, spectrum adaptation and restricted channel occupancy are also considered in the proposed strategy in order to achieve better performance in the secondary network. Accordingly, a partial channel occupancy mode, w…
Capacity Upper Bound of Channel Assembling in Cognitive Radio Networks with Quasistationary Primary User Activities
2013
In cognitive radio networks (CRNs) with multiple channels, various channel-assembling (ChA) strategies may be applied to secondary users (SUs), resulting in different achieved capacity. However, there is no previous work on determining the capacity upper bound (UB) of ChA for SUs under given system configurations. In this paper, we derive the maximum capacity for CRNs with ChA through Markov chain modeling, considering that primary user (PU) activities are relatively static, compared with SU services. We first deduce a closed-form expression for the maximum capacity in a dynamic ChA strategy and then demonstrate that no other ChA strategy can provide higher capacity than that achieved by th…
Aggregated Packet Transmission in Duty-Cycled WSNs: Modeling and Performance Evaluation
2017
[EN] Duty cycling (DC) is a popular technique for energy conservation in wireless sensor networks (WSNs) that allows nodes to wake up and sleep periodically. Typically, a single-packet transmission (SPT) occurs per cycle, leading to possibly long delay. With aggregated packet transmission (APT), nodes transmit a batch of packets in a single cycle. The potential benefits brought by an APT scheme include shorter delay, higher throughput, and higher energy efficiency. In the literature, different analytical models have been proposed to evaluate the performance of SPT schemes. However, no analytical models for the APT mode on synchronous DC medium access control (MAC) mechanisms exist. In this …