Neural Network Based Optimal Control with Constraints

In the present paper the problems of the optimal control of systems when constraints are imposed on the control is considered. The optimality conditions are given in the form of Pontryagin’s maximum principle. The obtained piecewise linear function is approximated by using feedforward neural network. A numerical example is given.

Formalization of Structural Constraints of Relationships in Model „Entity-Relationship”

The basic conceptions of the model „entity-relationship” as entities, relationships, structural constraints of the relationships (index cardinality, participation degree, and structural constraints of kind (min, max)) are considered and formalized in terms of relations theory. For the binary relations two operators (min and max) are introduced; structural constraints are determined in terms of the operators; the main theorem about compatibility of these operators’ values on the source relation and inversion to it is given here.

Automata–based Method for Solving Systems of Linear Constraints in {0,1}

We consider a finite state automata based method of solving a system of linear Diophantine equations with coefficients from the set {-1,0,1} and solutions in {0,1}.

Approximating the MaxMin and MinMax Area Triangulations using Angular Constraints

* A preliminary version of this paper was presented at XI Encuentros de Geometr´ia Computacional, Santander, Spain, June 2005.

Explicit Solutions of Nonlocal Boundary Value Problems, Containing Bitsadze-Samarskii Constraints

MSC 2010: 44A35, 35L20, 35J05, 35J25

Optimality Conditions for D.C. Vector Optimization Problems under D.C. Constraints

2000 Mathematics Subject Classification: Primary 90C29; Secondary 49K30.

Control Systems with Constraints and Uncertain Initial Conditions

AMS subject classification: 49N55, 93B52, 93C15, 93C10, 26E25.

First-Order Conditions for Optimization Problems with Quasiconvex Inequality Constraints

2000 Mathematics Subject Classification: 90C46, 90C26, 26B25, 49J52.

Non-stationary stochastic inventory lot-sizing with emission and service level constraints in a carbon cap-and-trade system

Firms worldwide are taking major initiatives to reduce the carbon footprint of their supply chains in response to the growing governmental and consumer pressures. In real life, these supply chains face stochastic and non-stationary demand but most of the studies on inventory lot-sizing problem with emission concerns consider deterministic demand. In this paper, we study the inventory lot-sizing problem under non-stationary stochastic demand condition with emission and cycle service level constraints considering carbon cap-and-trade regulatory mechanism. Using a mixed integer linear programming model, this paper aims to investigate the effects of emission parameters, product- and system-related features on the supply chain performance through extensive computational experiments to cover general type business settings and not a specific scenario. Results show that cycle service level and demand coefficient of variation have significant impacts on total cost and emission irrespective of level of demand variability while the impact of product's demand pattern is significant only at lower level of demand variability. Finally, results also show that increasing value of carbon price reduces total cost, total emission and total inventory and the scope of emission reduction by increasing carbon price is greater at higher levels of cycle service level and demand coefficient of variation. The analysis of results helps supply chain managers to take right decision in different demand and service level situations.

Financial constraints and technical efficiency:some empirical evidence for Italian producers' cooperatives

In this paper, we test the extent to which producers' cooperatives can experience an increase in technical efficiency following a tightening of financial constraints. This hypothesis is tested on a sample of Italian conventional and cooperative firms for the wine production and processing sector, using frontier analysis. The results support the hypothesis that increasing financial pressure can affect positively the cooperatives efficiency. Journal compilation © CIRIEC 2010.

Semi-supervised Gaussian process latent variable model with pairwise constraints

In machine learning, Gaussian process latent variable model (GP-LVM) has been extensively applied in the field of unsupervised dimensionality reduction. When some supervised information, e.g., pairwise constraints or labels of the data, is available, the traditional GP-LVM cannot directly utilize such supervised information to improve the performance of dimensionality reduction. In this case, it is necessary to modify the traditional GP-LVM to make it capable of handing the supervised or semi-supervised learning tasks. For this purpose, we propose a new semi-supervised GP-LVM framework under the pairwise constraints. Through transferring the pairwise constraints in the observed space to the latent space, the constrained priori information on the latent variables can be obtained. Under this constrained priori, the latent variables are optimized by the maximum a posteriori (MAP) algorithm. The effectiveness of the proposed algorithm is demonstrated with experiments on a variety of data sets. © 2010 Elsevier B.V.

Optimal redistricting under geographical constraints: Why "pack and crack" does not work

We show that optimal partisan redistricting with geographical constraints is a computationally intractable (NP-complete) problem. In particular, even when voter's preferences are deterministic, a solution is generally not obtained by concentrating opponent's supporters in \unwinnable" districts ("packing") and spreading one's own supporters evenly among the other districts in order to produce many slight marginal wins ("cracking").

A fedezetlen bankközi forintpiac hálózati dinamikájának vizsgálata a likviditási válság előtt és után (Examination of the network dynamics of the uncovered interbank forint markel before the liquidity crisis and after)

A cikkben a magyar fedezetlen bankközi forintpiac hálózatának időbeli alakulását vizsgáljuk 2002 decemberétől 2009 márciusáig. Bemutatjuk a piac általános jellemzőit (forgalom, kamatláb, koncentráció stb.) és az alapvető hálózati mutatókat. Azt tapasztaljuk, hogy az időszak első felében ezek a jellemzők lényegében stabilak voltak. 2006-2007-től kezdve azonban a mutatók egy része kezdett jelentősen megváltozni: a hitelfelvevők koncentrációja nőtt, az átlagos közelség és az átlagos fokszám csökkent, továbbá a hálózat magjának mérete is csökkent. Ezek a jelek arra utalhatnak, hogy a bankok már a válság kitörése előtt érzékelték a növekvő hitelkockázatot, és egyre inkább megválogatták, hogy kinek adnak hitelt. Figyelemre méltó, hogy mindeközben az általános piaci mutatók (forgalom, kamatláb, illetve ezek volatilitása) semmiféle változásra utaló jelet nem tükröztek egészen 2008 októberéig, de ekkor hirtelen minden mutatóban egyértelművé vált a rezsimváltás. Végül részletesen elemezzük az egyes szereplők viselkedését, és megmutatjuk, hogy válságban az egyes szerepek drasztikusan megváltoztak (például forrásokból nyelők lettek, és fordítva). / === / The article examines the changes in the network of Hungary's uncovered interbank forint market over the period Decembcr 2000 to March 2009. It presents the general features of the market (volume, interest rates, concentration etc.) and its basic network. It is found that the features were largely stable in the first half of the period, but some of the indicators began to change significantly in 2006-7: the concentration of borrowers incrcased, average distance and average degree declined, as did the size of the core of the network. These signs pointed to the fact that the banks had sensed an increase in credit risk even before the crisis broke and were becoming increasingly choosy selective in their lending. Meanwhile, however. there aerc no indications of change in the general market indicators (volume, interest rates, or volatility of these) right up to October 2008, when the change of regime was clear in all indicators. Finally, the authors analyse in detail the behaviour of each participant and show that thc roles of some altered drastically with the crisis (e.g. sources became consumers and vice versa).

A likviditási mutatószámok struktúrája (Structure of liquidity measures)

A likviditás mérésére többféle mutató terjedt el, amelyek a likviditás jelenségét különböző szempontok alapján számszerűsítik. A cikk a szakirodalom által javasolt, különféle likviditási mutatókat elemzi sokdimenziós statisztikai módszerekkel: főkomponens-elemzés segítségével keresünk olyan faktorokat, amelyek legjobban tömörítik a likviditási jellemzőket, majd megnézzük, hogy az egyes mutatók milyen mértékben mozognak együtt a faktorokkal, illetve a korrelációk alapján klaszterezési eljárással keresünk hasonló tulajdonságokkal bíró csoportokat. Arra keressük a választ, hogy a rendelkezésünkre álló minta elemzésével kialakított változócsoportok egybeesnek-e a likviditás egyes aspektusaihoz kapcsolt mutatókkal, valamint meghatározhatók-e olyan összetett likviditási mérőszámok, amelyeknek a segítségével a likviditás jelensége több dimenzióban mérhető. / === / Liquidity is measured from different aspects (e.g. tightness, depth, and resiliency) by different ratios. We studied the co-movements and the clustering of different liquidity measures on a sample of the Swiss stock market. We performed a PCA to obtain the main factors that explain the cross-sectional variability of liquidity measures, and we used the k-means clustering methodology to defi ne groups of liquidity measures. Based on our explorative data analysis, we formed clusters of liquidity measures, and we compared the resulting groups with the expectations and intuition. Our modelling methodology provides a framework to analyze the correlation between the different aspects of liquidity as well as a means to defi ne complex liquidity measures.