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We optimise a postal delivery problem with time and capacity constraints imposed on vehicles and nodes of the logistic network. Time constraints relate to the duration of routes, whereas capacity constraints concern technical characteristics of vehicles and postal operation outlets. We consider a method which can be applied to a brownfield scenario, in which capacities of outlets can be relaxed and prospective hubs identified. As a solution, we apply a genetic algorithm and test its properties both in small case studies and in a simulated problem instance of a larger (i.e. comparable with real-world instances) size. We show that the genetic operators we employ are capable of switching between solutions based on direct origin-to-destination routes and solutions based on transfer connections, depending on what is more beneficial in a given problem instance. Moreover, the algorithm correctly identifies cases in which volumes should be shipped directly, and those in which it is optimal to use transfer connections within a single problem instance, if an instance in question requires such a selection for optimality. The algorithm is thus suitable for determining hubs and satellite locations. All considerations presented in this paper are motivated by real-life problem instances experienced by the Polish Post, the largest postal service provider in Poland, in its daily plans of delivering postal packages, letters and pallets.

In this article we use pollen data from six sites in southern Greece to study long-term vegetation change in this region from 1000 BCE to 600 CE. Based on insights from environmental history, we interpret our estimated trends in the regional presence of cereal, olive and vine pollen as proxies for structural changes in agricultural production. We present evidence that there was a market economy in ancient Greece and a major trade expansion several centuries before the Roman conquest. Our results are consistent with auxiliary data on settlement dynamics, shipwrecks and ancient oil and wine presses. 1. Historical Background 2. Data and Method 2.1. Data 2.2. Method 3. Empirical Results 3.1. Pre-Roman Trade: Cereals, Olives and Vines 3.2. Alternative Explanations 4. Validation of the Methodology 4.1. Archaeological Field Surveys 4.2. Mediterranean Shipwrecks 4.3. Oil and Wine Presses 5. Further Evidence 5.1. Historical Literature 5.2. Evidence on Comparative Advantage 5.3. Distance to the Black Sea 6. Conclusion

This paper discusses the results of a numerical analysis of the existing palynological evidence from medieval and early modern Balkans and Anatolia; as such, it hopes to provide new quantitative data for the study of Byzantine and Ottoman economic history. After presenting the palynological database prepared for this project – as well as the numerical methods developed specifically to deal with this material - the core of the paper is devoted to historical interpretation. In the first section we deal with the late antique and early medieval periods, demonstrating that signs of both late antique agrarian prosperity and early medieval economic collapse may be observed across Greece, Macedonia and Anatolia. The following section focuses on evidence for the development of a pastoral economy in the central Balkan mountain ranges, between the early Middle Ages and the Ottoman era. The third section discusses environmental aspects of the middle Byzantine economic revival. Finally, the paper focuses on how different regions of the Balkans and Anatolia fared during the late Byzantine and Ottoman periods; in particular, we demonstrate how the Byzantine economic system came to an end, and how a new economic geography emerged during the Ottoman era.

In this paper the dynamic responses of labor markets to macroeconomic shocks in eight CEE countries are empirically analyzed in panel SVECM. Identification of shocks, interpreted as real wage, productivity, labor demand and supply shocks, is based on DSGE model with labor market explicitly modeled after Mortensen and Pissarides (1994). Fluctuations in foreign demand are controlled for and the model is estimated with panel procedure, which improves estimation’s precision. We show that propagation of shocks on NMS labor markets fairly resembles that characterizing OECD countries. Productivity improving shocks temporarily increase unemployment. Positive labor demand shocks increase employment, depress unemployment, rise real average wages, and were found to be the main determinant of variability of employment and unemployment in the short-run. In the medium term, in Czech Republic, Latvia, Lithuania and Poland innovations in wages seem to be prevalent drivers of employment and unemployment. The retrospective simulations of the model show that Baltic states and Poland were significantly affected by the collapse of Russian exports in late 1990s, and in 2000 an adverse labor demand shock hit all NMS, except for Hungary and Slovenia. However, the flexibility of wages is found to be crucial factor behind the diverse labor market performance in the region. Slovenia and Estonia fared best when it comes to flexibility of wages on macro level, on the other hand in Czech Republic, Lithuania and Poland downward wage rigidities were especially binding after employment-contracting shocks.

It is well known that central bank policies affect not only macroeconomic aggregates, but also their distribution across economic agents. Similarly, a number of papers demonstrated that heterogeneity of agents may matter for the transmission of monetary policy to macro variables. Despite this, the mainstream monetary economics literature has so far been dominated by dynamic stochastic general equilibrium models with representative agents. This paper aims to tilt this imbalance towards heterogeneous agents setups by surveying the main positive and normative findings of this line of the literature, and suggesting areas in which these models could be implemented. In particular, we review studies that analyse the heterogeneity of (i) households’ income, (ii) households’ preferences, (iii) consumers’ age, (iv) expectations and (v) firms’ productivity and financial position. We highlight the results on issues that, by construction, cannot be investigated in a representative agent framework and discuss important papers modifying the findings from the representative agent literature.

The literature on exchange rate forecasting is vast. Many researchers have tested whether implications of theoretical economic models or the use of advanced econometric techniques can help explain future movements in exchange rates. The results of the empirical studies for major world currencies show that forecasts from a naive random walk tend to be comparable or even better than forecasts from more sophisticated models. In the case of the Polish zloty, the discussion in the literature on exchange rate forecasting is scarce. This article fills this gap by testing whether non-linear time series models are able to generate forecasts for the nominal exchange rate of the Polish zloty that are more accurate than forecasts from a random walk. Our results confirm the main findings from the literature, namely that it is difficult to outperform a naive random walk in exchange rate forecasting contest.

In this paper we introduce a new source of data to economic history: palynological data or, in other words, information about pollen grains which are preserved in the bottom sediments of various water basins. We discuss how this data is collected and how it should be interpreted; develop new methods for aggregating this information into regional trends in agricultural output; construct an extensive dataset with a large number of pollen sites from Central Europe; and use our methods to study the economic history of Greater Poland, Lesser Poland, Bohemia, Brandenburg, and Lower Saxony since the first century AD.

Observed macroeconomic data – notably GDP growth rate, inflation and interest rates – can be, and usually are skewed. Economists attempt to fit models to data by matching first and second moments or co-moments, but skewness is usually neglected. It is so probably because skewness cannot appear in linear (or linearized) models with Gaussian shocks, and shocks are usually assumed to be Gaussian. Skewness requires non-linearities or non-Gaussian shocks. In this paper we introduce skewness into the DSGE framework assuming skewed normal distribution for shocks while keeping the model linear (or linearized). We argue that such a skewness can be perceived as structural, since it concerns the nature of structural shocks. Importantly, the skewed normal distribution nests the normal one, so that skewness is not assumed, but only allowed for. We derive elementary facts about skewness propagation in the state space model and, using the well-known Lubik-Schorfheide model, we run simulations to investigate how skewness propagates from shocks to observables in a standard DSGE model. We also assess properties of an ad hoc two-steps estimator of models’ parameters, shocks’ skewness parameters among them.

The paper documents elements of work on the dynamic stochastic general equilibrium (DSGE) SOEPL model that has been carried out in recent years at the National Bank of Poland. In 2009 a new version of the model was developed (called SOEPL−2009) which in 2010 is to support an econometric model and experts’ forecasts in mid-term forecasting of inflation and economic activity. The paper consists of three basic parts. The first part is introductory and briefly outlines the development of macroeconometric methods which brought about the creation of new-keynesian models specified within the dynamic stochastic general equilibrium approach. The remaining two parts of the paper report specification, estimation results and some properties of the SOEPL−2009 DSGE model.

It is well-known that central bank policies affect not only macroeconomic aggregates, but also their distribution across economic agents. Similarly, a number of papers demonstrated that heterogeneity of agents may matter for the transmission of monetary policy on macro variables. Despite this, the mainstream monetary economics literature has so far been dominated by dynamic stochastic general equilibrium (DSGE) models with representative agents. This article aims to tilt this imbalance towards heterogeneous agents setups by surveying the main positive and normative findings of this line of the literature, and suggesting areas in which these models could be implemented. In particular, we review studies that analyze the heterogeneity of (i) households’ income, (ii) households’ preferences, (iii) consumers’ age, (iv) expectations, and (v) firms’ productivity and financial position. We highlight the results on issues that, by construction, cannot be investigated in a representative agent framework and discuss important papers modifying the findings from the representative agent literature.

In the paper, by means of numerical experiments conducted on artificially constructed problem instances, we test penalty rules for constrained genetic optimization of the Capacitated Heterogeneous Vehicle Routing Problem with Time-Windows in a bi-objective framework. Optimized criteria are cost minimization and capacity utilization maximization. Two approaches are employed – scalarization of objectives and dominance-based evaluation of solutions. We show that it is possible to handle infeasibility in such a way, that this risk of divergence to regions of infeasibility is acceptable. The most secure penalty rule among the tested ones turns out to be the rule which explicitly controls the proportion of infeasible solutions in the population. This rule, along with the rule which accounts only the notion of solutions distance from the feasible set, outperforms rules based on time-penalties and best to best-feasible solution comparison over considered case studies.

It is well known that central bank policies affect not only macroeconomic aggregates, but also their distribution across economic agents. Similarly, a number of papers demonstrated that heterogeneity of agents may matter for the transmission of monetary policy to macro variables. Despite this, the mainstream monetary economics literature has so far been dominated by dynamic stochastic general equilibrium models with representative agents. This paper aims to tilt this imbalance towards heterogeneous agents setups by surveying the main positive and normative findings of this line of the literature, and suggesting areas in which these models could be implemented. In particular, we review studies that analyse the heterogeneity of (i) households’ income, (ii) households’ preferences, (iii) consumers’ age, (iv) expectations and (v) firms’ productivity and financial position. We highlight the results on issues that, by construction, cannot be investigated in a representative agent framework and discuss important papers modifying the findings from the representative agent literature.

The literature on exchange rate forecasting is vast. Many researchers have tested whether implications of theoretical economic models or the use of advanced econometric techniques can help explain future movements in exchange rates. The results of the empirical studies for major world currencies show that forecasts from a naive random walk tend to be comparable or even better than forecasts from more sophisticated models. In the case of the Polish zloty, the discussion in the literature on exchange rate forecasting is scarce. This article fills this gap by testing whether non-linear time series models are able to generate forecasts for the nominal exchange rate of the Polish zloty that are more accurate than forecasts from a random walk. Our results confirm the main findings from the literature, namely that it is difficult to outperform a naive random walk in exchange rate forecasting contest.

The paper documents elements of work on the dynamic stochastic general equilibrium (DSGE) SOEPL model that has been carried out in recent years at the National Bank of Poland. In 2009 a new version of the model was developed (called SOEPL−2009) which in 2010 is to support an econometric model and experts’ forecasts in mid-term forecasting of inflation and economic activity. The paper consists of three basic parts. The first part is introductory and briefly outlines the development of macroeconometric methods which brought about the creation of new-keynesian models specified within the dynamic stochastic general equilibrium approach. The remaining two parts of the paper report specification, estimation results and some properties of the SOEPL−2009 DSGE model.

In the paper we examine a modification of the classical Vehicle Routing Problem (VRP) in which shapes of transported cargo are accounted for. This problem, known as a three‐dimensional VRP with loading constraints (3D‐VRP), is appropriate when transported commodities are not perfectly divisible, but they have fixed and heterogeneous dimensions. In the paper restrictions on allowable cargo positionings are also considered. These restrictions are derived from business practice and they extended the baseline 3D‐VRP formulation as considered by Koloch and Kaminski (2010). In particular, we investigate how additional restrictions influence relative performance of two proposed optimization algorithms: the nested and the joint one. Performance of both methods is compared on artificial problems and on a big‐scale real life case study.

We analyze with panel SVECM the impact of real wage, productivity, labor demand and supply shocks on the eight CEE economies during 1996-2007. We use a set of long-run restrictions, derived from the DSGE model with explicitly modeled labor market, to identify these structural shocks. Fluctuations in foreign demand are controlled for. We find that the propagation of shocks on CEE labor markets resembles the one found for OECD countries. Labor demand shocks emerge as the main determinant of employment and unemployment variability in the short-run. The retrospective simulations of the model show that the wage adjustments were important factor behind the diverse labor market performance of the countries studied. Downward wage rigidities were especially binding after employment-contracting shocks in Poland, Czech Republic, Lithuania.

This Report is a third in the series Employment in Poland. Its subtitle, which reads Security on a flexible labour market, is a reflection of one of the key dilemmas in social and economic policy, namely the necessity to reconcile the development of effective economic structures that react in a flexible manner to changing external circumstances with the assurance of social security and stability to all citizens. In the subsequent parts of this Report we demonstrate that in many cases this conflict between flexibility and security is only ostensible and that it is therefore possible to organise the labour market institutions in such a way that thanks to greater flexibility negative disturbances, which are bound to hit this market, could be absorbed more easily and quickly and their consequences for the public would be less severe. This Report consists of four Parts. In Part I, we go deeper into the macroeconomic analysis initiated in the previous edition of Employment in Poland identifying key factors responsible for different evolutions of employment and unemployment in eight Central European countries that joined the European Union in May 2004. We point out that although in the past external shocks were of foremost importance to unemployment and employment fluctuations in the region, nowadays countries vulnerability to typical macroeconomic shocks affecting their major trade partners in considerably smaller. At the same time, we argue that, next to cyclical fluctuations, it was wage rises – unrelated to changes in productivity, that constituted an important internal disturbance which determined the developments on the labour markets in the region. We assert that greater real wage flexibility could allow some countries, including Poland, to lower actual unemployment levels and to better absorb external disturbances in their economies. Last but not least, we emphasise that restrictive monetary policies implemented in the past in reaction to supply shocks that affect above all the price structure and not price levels, largely intensified the negative consequences of the economic slowdown in Poland by increasing unemployment and decreasing employment. Part II treats on the impact on market efficiency of those labour market institutions that are intended to enhance the adaptability of households and businesses to inevitable macroeconomic disturbances as well as to different functions that work serves at different stages of human and company life. What is more, in our analysis, we focus on non-standard work arrangements and indicate that in those economies where protection measures applied to the traditional employment relationship are restrictive and where the use of alternative work arrangements is hindered, the period of absorption of aggregate disturbances is longer and the reallocation of production factors is less effective than in labour markets which with less restrictive employment protection legislation. We emphasise that in all Central European countries, including Poland, the popularity of flexible employment arrangements is much less than in Western Europe. It is also highly heterogeneous. As much as in the recent years Poland has seen a dynamic spread of temporary work contracts and integration of temporary work agencies in the functioning of the labour market, the potential of atypical employment arrangements in Poland is largely unfulfilled when it comes to economic activity of people who combine work and family life or who find it difficult to work full-time due to age or health reasons. In Part III, we look at the issue of work remuneration from macro- and micro-perspective alike. We argue that the recent rapid wage growth can be interpreted as a belated reaction to the economic upsurge which started after 2003 and that its persistence may only become adverse to the labour market when the gap between wages and labour productivity, which came into being during the period of slowdown, is fully closed. The persistent growth of wage inequalities in Poland during the transition period was due to the fact that rapid technological progress favoured some professional and social groups more than others. What is essential here is the increasing return on formal education and rising premiums on work in managerial positions as well as increasingly diverse individual and market characteristics of Polish workers. In this context, it is the public sector that stands out because it offers relatively higher wages to low-qualified workers and it pays relatively less to people with higher qualifications. Wage arrangements in the public sector are less flexible than in the private sector and therefore they are less prone to cyclical fluctuations, which leads to swings in wage attractiveness of this sector. Towards the end of Part III we evidence that, in international comparison, the gender wage gap in Poland is relatively small. Notwithstanding the above, even if differences in individual and employer characteristics as well as working time are taken into consideration, women still earn about ten percent less than men. At the same time, we emphasise that, based on the existing databases, it is impossible to decide whether this fact reflects real barriers to the advancement of women or whether it is rather a consequence of different preferences of men and women which determine different paths of their professional careers. Part IV focuses on one of the key instruments of the contemporary social and economic policy in developed economies, namely active labour market policies (ALMP). We describe the evolution of different types of ALMP over time in OECD and EU countries and discuss the results of international research on the effectiveness of this form of support to the unemployed and economically inactive. The main objective of this Part, however, is to assess the active labour market policies implemented in Poland. We carry out our assessment at the level of aggregates as well as based on the individual survey study of effectiveness of ALMP which we have conducted for the purposes of this Report. It is the first attempt at producing a rigorous and comprehensive evaluation of ALMP effectiveness in Poland in the recent years. Our analysis evidences that a part of resources allocated to active labour market policies does not translate into the greater chance for their beneficiaries to find a job. This concerns above all intervention and public works which turn out to be completely inefficient when it comes to opening up job opportunities to the unemployed. At the same time, however, we point out that even for those policies that are characterised by positive net efficiency, such as internships and traineeships, the deadweight loss is also high, i.e. support is extended to groups whose situation is relatively good, whereas more difficult cases are neglected. The problem of ALMP being misaddressed also affects the fact that actions undertaken by local labour offices in Poland in the area of agency and advisory support have no significant impact on the situation of unemployed people which clearly distinguishes Poland from other European countries.

We present an argumentative approach to agent-based modeling where agents are socially embedded and exchange information by means of simulated dialogues. We argue that this approach can be beneficial in social simulations, allowing for a better representation of agent reasoning, that is also accessible to the non computer science savvy, thus filling a gap between scholars that use BDI frameworks and scholars who do not in social sciences.