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51.
S. M.D. Queirós L. G. Moyano J. de Souza C. Tsallis 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(2):161-167
We present results about financial market observables, specifically
returns and traded volumes. They are obtained within the current nonextensive statistical mechanical framework based on the
entropy
. More precisely, we present stochastic dynamical mechanisms which mimic probability density functions empirically observed.
These mechanisms provide possible interpretations for the emergence of the entropic
indices q in the time evolution of the corresponding observables. In addition to this, through multi-fractal analysis of return
time series, we verify that the dual relation qstat+qsens=2 is numerically satisfied, qstat and qsens being associated to the probability density function and to the sensitivity to initial conditions respectively. This type
of simple relation, whose understanding remains ellusive, has been empirically verified in various other systems. 相似文献
52.
A model for the dynamics of price adjustment in a single commodity market is developed. Nonlinearities in both supply and demand functions are considered explicitly, as are delays due to production lags and storage policies, to yield a nonlinear integrodifferential equation. Conditions for the local stability of the equilibrium price are derived in terms of the elasticities of supply and demand, the supply and demand relaxation times, and the equilibrium production-storage delay. The destabilizing effect of consumer memory on the equilibrium price is analyzed, and the ensuing Hopf bifurcations are described. 相似文献
53.
We consider the problem of stock repurchase over a finite time horizon. We assume that a firm has a reservation price for the stock, which is the highest price that the firm is willing to pay to repurchase its own stock. We characterize the optimal policy for the trader to maximize the total number of shares that they can buy over a fixed time horizon. In particular, we study a greedy policy, which involves in each period buying a quantity that drives stock price to the reservation price. 相似文献
54.
Nergiz KasimbeyliTugba Sarac Refail Kasimbeyli 《Journal of Computational and Applied Mathematics》2011,235(16):4663-4674
This paper considers a one-dimensional cutting stock and assortment problem. One of the main difficulties in formulating and solving these kinds of problems is the use of the set of cutting patterns as a parameter set in the mathematical model. Since the total number of cutting patterns to be generated may be very huge, both the generation and the use of such a set lead to computational difficulties in solution process. The purpose of this paper is therefore to develop a mathematical model without the use of cutting patterns as model parameters. We propose a new, two-objective linear integer programming model in the form of simultaneous minimization of two contradicting objectives related to the total trim loss amount and the total number of different lengths of stock rolls to be maintained as inventory, in order to fulfill a given set of cutting orders. The model does not require pre-specification of cutting patterns. We suggest a special heuristic algorithm for solving the presented model. The superiority of both the mathematical model and the solution approach is demonstrated on test problems. 相似文献
55.
Christos Ordoudis Pierre Pinson Juan M. Morales 《European Journal of Operational Research》2019,272(2):642-654
In energy systems with high shares of weather-driven renewable power sources, gas-fired power plants can serve as a back-up technology to ensure security of supply and provide short-term flexibility. Therefore, a tighter coordination between electricity and natural gas networks is foreseen. In this work, we examine different levels of coordination in terms of system integration and time coupling of trading floors. We propose an integrated operational model for electricity and natural gas systems under uncertain power supply by applying two-stage stochastic programming. This formulation co-optimizes day-ahead and real-time dispatch of both energy systems and aims at minimizing the total expected cost. Additionally, two deterministic models, one of an integrated energy system and one that treats the two systems independently, are presented. We utilize a formulation that considers the linepack of the natural gas system, while it results in a tractable mixed-integer linear programming (MILP) model. Our analysis demonstrates the effectiveness of the proposed model in accommodating high shares of renewables and the importance of proper natural gas system modeling in short-term operations to reveal valuable flexibility of the natural gas system. Moreover, we identify the coordination parameters between the two markets and show their impact on the system’s operation and dispatch. 相似文献
56.
《Operations Research Letters》2019,47(5):344-347
We consider exchange markets with single-unit endowments and demands where there is a bound on the size of the exchange cycles. The computational problem we study is that of computing a Pareto optimal and individually rational allocation. We present polynomial-time algorithms to compute a Pareto optimal and individually rational allocation when preferences are strict, the exchange bound is two, or when Pareto optimality is replaced with weak Pareto optimality. 相似文献
57.
E. Bompard Y. C. Ma E. Ragazzi 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(1-2):153-160
Competition has been introduced in the electricity markets with
the goal of reducing prices and improving efficiency. The basic idea which
stays behind this choice is that, in competitive markets, a greater quantity
of the good is exchanged at a lower price, leading to higher
market efficiency.
Electricity markets are pretty different from other commodities
mainly due to the physical constraints related to the network structure that
may impact the market performance. The network structure of the system on
which the economic transactions need to be undertaken poses strict physical
and operational constraints.
Strategic interactions among producers that game the market with the
objective of maximizing their producer surplus must be taken into account
when modeling competitive electricity markets. The physical constraints,
specific of the electricity markets, provide additional opportunity of
gaming to the market players. Game theory provides a tool to model such a
context. This paper discussed the application of game theory to physical constrained
electricity markets with the goal of providing tools for assessing the market
performance and pinpointing the critical network constraints that may impact
the market efficiency. The basic models of game theory specifically designed
to represent the electricity markets will be presented. IEEE30 bus test
system of the constrained electricity market will be discussed to show the
network impacts on the market performances in presence of strategic bidding
behavior of the producers. 相似文献
58.
U. Lucia G. Gervino 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(1-2):367-369
In this paper an analysis of the Stirling cycle in thermoeconomic
terms is developed using the entropy generation. In the thermoeconomic optimization of an
irreversible Stirling heat pump cycle the F function has been
introduced to evaluate the optimum for the higher and lower sources
temperature ratio in the cycle: this ratio represents the value which
optimizes the cycle itself. The variation of the function F is proportional to
the variation of the entropy generation, the maxima and minima of F has been evaluated in
a previous paper without giving the physical foundation of the method. We
investigate the groundwork of this approach: to study the
upper and lower limits of F function allows to determine the cycle stability and the
optimization conditions. The optimization consists in the best COP at
the least cost. The principle
of maximum variation for the entropy generation becomes the analytic
foundation of the optimization method in the thermoeconomic analysis
for an irreversible Stirling heat pump cycle. 相似文献
59.
Extreme value theory (EVT) focuses on modeling the tail behavior of a loss distribution using only extreme values rather than the whole data set. For a sample of 10 countries with dirty/free float regimes, we investigate whether paired currencies exhibit a pattern of asymptotic dependence. That is, whether an extremely large appreciation or depreciation in the nominal exchange rate of one country might transmit to another. In general, after controlling for volatility clustering and inertia in returns, we do not find evidence of extreme-value dependence between paired exchange rates. However, for asymptotic-independent paired returns, we find that tail dependency of exchange rates is stronger under large appreciations than under large depreciations. 相似文献
60.
Andreas P. Nawroth 《Physica A》2007,382(1):193-198