A project scheduling problem investigates a set of activities that have to be scheduled

due to precedence priority and resource constraints in order to optimize project-related

objective functions. This paper focuses on the multi-mode project scheduling problem concerning

resource constraints (MRCPSP). Resource allocation and leveling, renewable and

non-renewable resources, and time-cost trade-off are some essential characteristics which are

considered in the proposed multi-objective scheduling problem. In this paper, a novel hybrid

algorithm is proposed based on non-dominated sorting ant colony optimization and genetic

algorithm (NSACO-GA). It uses the genetic algorithm as a local search strategy in order to

improve the efficiency of the ant colony algorithm. The test problems are generated based on

the project scheduling problem library (PSPLIB) to compare the efficiency of the proposed

algorithm with the non-dominated sorting genetic algorithm (NSGA-II). The numerical result

verifies the efficiency of the proposed hybrid algorithm in comparison to the NSGA-II

algorithm.

The objective of the milk-run design problem considered in this paper is to minimize transportation

and inventory costs by manipulating fleet size and the capacity of vehicles and

storage areas. Just as in the case of an inventory routing problem, the goal is to find a periodic

distribution policy with a plan on whom to serve, and how much to deliver by what

fleet of tugger trains travelling regularly on which routes. This problem boils down to determining

the trade-off between fleet size and storage capacity, i.e. the size of replenishment

batches that can minimize fleet size and storage capacity. A solution obtained in the declarative

model of the milk-run system under discussion allows to determine the routes for each

tugger train and the associated delivery times. In this context, the main contribution of

the present study is the identification of the relationship between takt time and the size

of replenishment batches, which allows to determine the delivery time windows for milkrun

delivery and, ultimately, the positioning of trade-off points. The results show that this

relationship is non-linear.

The article analyzes trends in steam coal flows (exports and imports) linked to production and consumption volumes. The analysis carried out in the article took the years from 2000 to 2019 into consideration. Coal is the second most important energy carrier. Its share in the structure of global consumption amounts to 27% and its production has an upward trend despite its decreasing share. The overall global upward trend of steam coal flows was disrupted twice over the period 2000–2019: by the effects of the 2007–2009 global financial crisis and the ongoing uncertainty of the global economy, as well as by the significant slowdown in the economic growth of developing countries (2014–2016). The European Union has seen large decreases in coal consumption over recent years, reflecting an accelerating decarbonization policy. The main area of coal trade is the Asia-Pacific basin. The Atlantic market currently accounts for about 20% of global steam coal trade, with seaborne trade covering about 95%. The volume of world trade (exports, imports) in steam coal is approximately one billion (bn) tons per year. The analysis carried out showed the following trend: decreasing coal exports to economically developed countries (mainly concentrated in Europe) and increasing exports to economies of developing countries, concentrated in the Asian part of the world. International Energy Agency (IE A) projections show that by 2040 the global coal production will fall from 5.6bn tons of coal equivalent (3.9bn tons of oil equivalent in 2019) to 5bn tce (3.5bn toe) at an average annual rate of –1.1%. Steam coal production is expected to decline by 10% to 4bn tce (2.8bn toe). Due to the fact that China is the largest producer, user and importer of steam coal in the world, all economic and political decisions taken by its government have strongly influenced international coal trade for years. For the Asia-Pacific basin alone, the IE A’s long-term forecasts predict an increase in coal-fired power generation over 2019. Forecasts regarding the coal’s share in global demand are not optimistic for many regions of the world (Europe, Africa, the Americas), predicting a significant decline in its demand. Yet, new markets for coal are emerging, especially in Asia and the Mediterranean basin, which may contribute to maintaining at least the current level of coal trade.

Poland’s economy is closely connected with European markets, particularly within the European Union: almost 90% of Polish commodity export goes to European countries and 80% is absorbed by other EU countries. The common European market is absorptive, safe and stabile, and goods and services sold there are duty free. But the high concentration of exports in this market implies a strong dependence on the modest growth dynamics and local fluctuations of demand, while reducing the gains that could be obtained from the presence in emerging markets which include several large and rapidly growing developing economies. The paper gives a general characteristics of those markets, including the information on their economic and population potential, and their place in the world economy – at present and in the future (according to current statistical data and long-run forecasts). The statistics of Polish foreign trade indicates a very small share of emerging countries in the geographical structure of Poland’s exports. The author describes the chances and threats combined with export expansion to these markets, emphasizing that the net balance of benefits and risks is clearly positive, which should encourage Polish enterprises to take a more active part in trade and cooperation with those countries and regions.

This paper presents data on the management of dimension stones in Poland in the period 2011– –2021. The domestic production of rocks suitable for the production of slabs, pitcher and curbs, etc. is estimated and the major varieties of rocks utilized for these purposes are indicated. Data on raw and processed products with regard to imports and exports are presented for crude and roughly worked blocks and slabs, worked dimension stones as well as pitcher, curbs and other road stones. In the first two groups, data is reported separately for:
- marbles, limestones and other carbonate rocks,
- granites,
- sandstones (distinguished as separate category in crude blocks and slabs group),
- other rocks.
Data on the volume of production, imports and exports is utilized for the calculation of the apparent consumption of dimension stone in Poland. The conducted analyses revealed that its volume has been ranging from 1.4 to 1.9 million tons/year in 2013–2021 with the exception of the years 2011–2012 when it reached ca. 2.7 million tons/year. The most important group of rocks utilized in Poland as dimension stones are granites. These originated primarily from domestic deposits but they are also imported from various directions, primarily from the Republic of South Africa and India (crude blocks and slabs), China (worked dimension stones) as well as from Sweden and Norway in 2011–2012 (significant amounts of hydrotechnical stones). A nother significant group of rocks utilized in Poland as dimension stones are sandstones (with a share of imports in total domestic consumption not exceeding 1%) while marbles, limestones and other carbonate rocks are of marginal importance (primarily imported in the form of worked dimension stones from China, the Czech Republic, Italy and Turkey).

The first record of an oriental, alien aphid species belonging to the genus Takecallis, associated with the cold hardy bamboo Fargesia rufa T.P.Yi, collected in Słupsk, Pomeranian Voivodeship, Poland, is provided. The increase in worldwide trade of new frost-resistant ornamental bamboo varieties as a source of introducing alien species of insects in Europe and the role of garden centers as potential dispersal sites for these species is discussed.

Approximately 95% of international trade in steam coal is concentrated in two areas: Asia-Pacific and Atlantic. Prices on the international market depend on the largest exporters and users of coal. The aim of the article is to characterize the price trends that took place in the international trade of energy coal in the years 2000–2020 and to distinguish price indices which, in the opinion of the authors, currently play an important role in this trade. The analysis of steam coal prices in international markets in 2000–2020 made it possible to highlight five periods of rising prices, four periods of falling prices, and one period of the stabilisation of prices. A detailed analysis of the highlighted periods of steam coal price fluctuations in 2000–2020 made it possible to identify groups of factors that significantly affect the level of prices of the analyzed coal in the long term. International steam coal markets are interlinked despite periodic volatility. A very important factor influencing world steam coal prices is the situation in China as it is the largest producer, user and importer of steam coal. A small change in coal production in China significantly affects the volume of trade on the international market. Therefore, the level of freight prices is an important factor influencing the price level for the customer. FOB Australia prices are also correlated with coal suppliers to the European market and Asia-Pacific market in this paper. The very high correlation coefficients obtained confirm the close relationship between the prices of these coals. For many years, the European market has no longer been a trendsetter in international coal markets but has instead been affected by general trends.

The aim of this article is to provide an overview of other alternative directions of coal supply to Poland following the February 2022 embargo on coal imports from Russia. Due to the dominant role of steam coal in imports to Poland, the authors focused on this type of coal. Analysis of the share of Russian steam coal imported into Poland in domestic consumption and production suggests that this commodity has played a relatively important role in the Polish market. In 2010–2021, between 4.8 and 12.9 million tonnes were imported annually from Russia to Poland, accounting for 8–25% of domestic steam-coal consumption. In 2018–2021, steam coal imported into Poland accounted for 22–29% of the volume of coal shipped by Russia to all EU -27 countries. In order to fill the gap left by Russian coal, this article considers alternative routes of coal supply to Poland, namely from Australia, Indonesia, Colombia, South Africa and the US, and presents the qualitative characteristics of the coal offered by these alternative routes of coal supply and traded on the international market. Between 2010 and 2021, steam-coal-price offers from these countries followed a consistent trend, with the difference between the minimum and maximum offer ranging from USD 5–32/tonne. As the steam coal supply of each of the analyzed routes of supply is fraught with some risk, the authors have also identified in the article those directions that may present some difficulties. It was found that coal offerings from Australia, South Africa, Indonesia and Colombia have low sulphur content (less than 1%), while coals from Australia and South Africa have relatively high ash content (from 12% to nearly 25%). Towards the end, the article also addresses issues related to the transport of coal to Poland and its dispatching within the country. As the analyzed alternative directions of coal imports involve importing this commodity by sea, the authors also analyzed the reloading capacity of Polish seaports and the rail transport fleet.

The article has presented the assumptions underlying the organization of emissions trading of greenhouse gases with a particular emphasis on CO2 emission allowances. Through the analysis of the literature, international activities were undertaken aimed at reducing greenhouse gas emissions into the atmosphere, starting from the First World Climate Conference organized in 1979. The origins and guidelines of the Kyoto Protocol were also given considerable attention. In addition to the description of the key assumptions of the Protocol and its main components, the characteristics of international trade in Kyoto units were also included. The mechanisms involved in international trade and the types of units traded in a detailed manner are described. In the next part of the article, emission trading systems operating in the world are characterized. In the second part of the paper special attention was paid to the conditionings of the European market, i.e. European Emissions Trading System – EU ETS. Historical events were presented that gave rise to the creation of the EU ETS. In the next steps, the types of units that are tradable were described. Furthermore, the trade commodity exchanges on which trade is conducted, the key factors determining the price of individual allowances are also indicated. In the last part of the article, relatively recent issues – the IED Directive and the BAT conclusions have been pointed out. Referring to the applicable regulations, the impact of their implementation on the situation of entities obliged to limit greenhouse gas emissions was analyzed. In the final phase, an attempt was made to assess the impact of IED and BAT to electricity prices.

In this study, effects of political stability, economic freedom and trade freedom of above-stated Fragile Five Countries consisting of Brazil, Indonesia,India, Turkey, and South Africa on the performance of FDI appeal was analyzed with first generation panel data analysis method for the 1996-2017 period. The cointegration analysis between series was conducted by means of Kao (1999) and Pedroni (2004) test. The analyses showed that political stability and trade freedom have a significant positive coefficient on the Fragile Five Countries’FDI. It was also determined that the impact of economic freedom on FDI was statistically insignificant. Thus, it was concluded that the most important determinant of FDI entry into countries is political stability. Error correction mechanisms of models have been working well. In addition, it was found that political stability, economic freedom, and trade freedom are the cause of foreign direct investment in the long-run.

The lithium market has experienced an unprecedented boom in recent years like a “golden age” and is one of the fastest growing raw material markets in the world. The fast growing demand for lithium is mainly related to the increase in the production of lithium-ion batteries used in electric or hybrid vehicles and portable electronic equipment, and to a lesser extent, in other strategic fields (military, nuclear technologies). This was reflected in a significant change in the structure of consumption, an increase in international trade and in the price of lithium raw materials. Moreover, in 2018 lithium was listed as a critical element for the national security and economy of the United States, and in 2020 it was also listed as a critical raw material for the European Union economy. It is also a time of increased exploration for new deposits, as well as mining processing and recycling. As a result, global lithium reserves have doubled in the last six years. All this prompted the authors to prepare an article in which the sources of lithium minerals and their resources, the basic factors determining the economic situation on the market, their prices and the possibilities of recycling and substitution are presented and assessed. Attention is also paid to the role of companies operating in Poland as significant partners on the European market of lithium-ion batteries. Lithium oxide and hydroxide and lithium carbonate are the main lithium raw materials used in Poland. In the absence of the country having its own deposits, they are imported, and the main suppliers are Chile, Western European countries and Russia.

Mineral-resource mining is a pillar of many state economies and, in many cases, it determines the welfare of the society. The mining of mineral resources provides the market with the raw materials that are traded and drives the economic and social development of countries, although it can also be a source of tensions and crises (e.g. the “curse of wealth”, “Dutch disease”). The trade of raw materials is conducted by exchanges, bilateral deals and other forms of transactions, and is regulated by trade regulations and contract agreements, and in most cases, constitutes a source of income for exporters. In this paper, the use of game-theory modelling for creating the selling price of mineral products on the basis of Polish export quotas for refined copper raw materials is proposed. Using a characteristic function created on the basis of reported export values, possible cooperation arrangements are defined and solutions are calculated for an n-person game of hypothetical coalitions of the major (in terms of volume) recipients of refined Polish copper, i.e. Germany, Italy and France. Alternative markets and possible supplies of cheaper raw material are excluded from the analyses, while the price spread between the rates paid by the buyers is taken into consideration. Among the many possibilities, the game core, the Shapley imputation and the Gately point are arbitrarily adopted as permissible solutions to the defined system. The obtained results are used for a speculative analysis relating to the possibility of renegotiating prices between the producer and recipients of the raw material. Marginal contributions resulting from Shapley’s solution are taken into account as is the power of individual trading-participant coalitions. The paper demonstrates that the recognition and adoption of solutions based on the n-personnel game model as impartial would require the redefinition of contracts and the rates paid for the raw material.

On fifth-generation wireless networks, a potential massive MIMO system is used to meet the ever-increasing request for high-traffic data rates, high-resolution streaming media, and cognitive communication. In order to boost the trade-off between energy efficiency (EE), spectral efficiency (SE), and throughput in wireless 5G networks, massive MIMO systems are essential. This paper proposes a strategy for EE 5G optimization utilizing massive MIMO technology. The massive MIMO system architecture would enhance the trade-off between throughput and EE at the optimum number of working antennas. Moreover, the EE-SE tradeoff is adjusted for downlink and uplink massive MIMO systems employing linear precoding techniques such as Multiple -Minimum Mean Square Error (M-MMSE), Regularized Zero Forcing (RZF), Zero Forcing (ZF), and Maximum Ratio (MR). Throughput is increased by adding more antennas at the optimum EE, according to the analysis of simulation findings. Next, utilizing M MMSE instead of RZF and ZF, the suggested trading strategy is enhanced and optimized. The results indicate that M-MMSE provides the best tradeoff between EE and throughput at the determined optimal ratio between active antennas and active users equipment’s (UE).

The Ways of the Diaspora in the narrative of Claudio Magris – One of the themes in the works of Claudio Magris is that of the frontiers between nations which have been divided by arbitrary political decisions. This is the case with Central Europe, which forms a sort of transnational melting pot and which has hosted the Hebrew Diaspora. The theme of the Diaspora plays a key role in many of Magris books, in particular Lontano da dove. In his recent novel, Non luogo a procedere, one of the topics is the slave trade, a sort of African Diaspora.

Cash is one of the most critical resources of a construction company that determines survival. Cash-flow management is essential for contractors, as lack of cash resources is one of the leading causes of bankruptcy in the construction industry, compared to most other sectors. The purpose of this paper is to identify factors affecting time and cost trade-off in multiple construction projects in Iraq. After reviewing a wide range of literature to determine the most common elements, a questionnaire is distributed to owners, consultants, supervising engineers, and contractors engaged in construction projects. The results of the questionnaire were analyzed using the relative importance index, arithmetic mean and standard deviation. The respondents namely assured Seventeen most essential factors; payments delay from client, progress payment due period, payment conditions, advanced payment, project delay, inaccurate project scheduling, variation orders, project duration, inaccurate project duration, profit, risk margin, project cost, cash flow forecasts, retentions percentage, estimating errors, materials cost, equipment cost, and labour cost.

The aim of the article to assess the functioning of the NewConnect market over 10 years from the organizer’s and participants’ perspective. This helps to diagnose the most important organizational advantages and problems of the Polish MTF, determine further development prospects and propose potential changes to neutralize the negative factors. To illustrate the problem, a comprehensive analysis will be made of aggregated statistical data from 2007–2017, which show the changes and trends on this market, and additionally include the data comparing the current state of the NewConnect market with other alternative markets organized by European stock exchanges.

The conducted research does not allow to view the NewConnect market as an organizational success. The analysis identified a number of problems in the functioning of the Polish MTF, ranging from the inappropriate organization of the primary market, resulting in the admittance of too high a number of issuers of dubious credibility, to the consequences appearing on the secondary shares market. It does not give unambiguous grounds to expect positive prospects for the market development in the future. In order to stop unfavorable trends and to improve the issuers’ quality, a discussion on the regulations regarding issuers’ admission, i.e. the size of the minimum equity, IPO, capitalization and the issue price of the debuting company, should be initiated.

This paper investigates the relationship between energy use and economic development in five South-Asian countries using national-level panel data from 1990 to 2014. Although many studies have already addressed the nexus between energy consumption and economic growth, there is a mixed finding. According to many researchers, South Asian countries have expanded energy consumption since the 1990s. Therefore, energy consumption as a variable for a specific period is considered for the countries of Bangladesh, India, Nepal, Pakistan and Sri Lanka. Furthermore, foreign direct investment (FDI) and international trade (IT) are also considered to be related variables in this study. Pooled ordinary least squares, random effects, and fixed effects estimation techniques are used to provide a reliable estimation, offsetting the country fixed effects. The fixed effect model is the most effective model that reveals the association between electricity usage and growth factors, as per the specification test and Hausman test. A statistically significant correlation was found between international trade, FDI, economic growth, and power usage. FDI has the highest impact on the rising power demand, followed by global commerce and per capita GDP (gross domestic product). More specifically, the study findings reveal that increased power consumption causes more investment, which results in increased economic growth in South Asian countries. The findings of the study further show that FDI significantly impacted upon power consumption and the area of SAARC’s energy demand, resulting in the entry of new technology and an increase in both economic growth and energy consumption. Future policies may focus on investment in the energy sector to promote economic development.

Whilst the extant scholarship offers a detailed exploration of why return migrants enter self-employment or engage in business initiatives in general, we know relatively little about their involvement in transnational economic activities which connect the previous destination coun-try with the origin one and how they compare to other kinds of entrepreneurial venture in this vein. This article aims to understand these motivations by using insights from 50 semi-structured interviews conducted with traders of used cars imported in Romania, a mass phe-nomenon in the Central and Eastern European area and beyond. An important result of this research is that entrepreneurs have to consider a multitude of factors in multiple locations when entering the used-car business. The article also suggests that entrepreneurial motivations among used-car traders are not fixed but, rather, can and do change over time.

A transition from generating electricity from conventional sources to generating it from renewables is one of drivers leading us towards a circular economy. Electricity is a specific product and regardless of where and how it is produced, it takes the same form. A novel aspect of the research is the examination of correlations and relationships between guarantees of origin. The research objective is to analyse the market for the guarantees of origin in the volatile price environment that we had late 2021 and early 2022. Therefore, we analysed demand for the guarantees in January 1, 2020 to June 30, 2022 and the correlation between the price of electricity and guarantees of origin. It was based on the secondary data analysis method and the use of Pearson’s correlation coefficient and a linear regression function. The authors of the study made a hypothesis that the trading volume would increase during the study period and that there would be a positive correlation between the price of energy and the guarantees of origin. A key finding of the study revealed a steady increase in the purchase of guarantees despite the rise in prices. The buying of the guarantees is not a top-down requirement, but rather a bottom-up action, which indicates growing social expectations towards enterprises to consume energy from renewable sources.

Most construction projects involve subcontracting some work packages. A subcontractor is employed on the basis of their bid as well as according to their availability. A viable schedule must account for resource availability constraints. These resources (e.g. crews, subcontractors) engage in many projects, so they become at the disposal for a new project only in certain periods. One of the key tasks of a planner is thus synchronizing the work of resources between concurrent projects. The paper presents a mathematical model of the problem of selecting subcontractors or general contractor’s crews for a time-constrained project that accounts for the availability of contractors, as well as for the cost of subcontracting works. The proposed mixed integer-binary linear programming model enables the user to perform the time/cost trade-off analysis.

In the first centuries after Christ, the Indian subcontinent entered the orbit of the Roman state’s trade interests. The subject of the exchange was a number of goods, including Roman coins. Their influx is documented by numerous finds as well as by ancient authors. One of the territories where we register quite a large number of Roman coin finds is the area of early historical Andhra. The specimens discovered here are found in various contexts, indicating their various applications. The hoards of silver and gold coins allow the observation of successive waves of the influx of Roman money, which is also confirmed by the finds of other categories – stray and settlement. The internal differentiation of the latter also allowed to define their mutual relations and tendencies in circulation. Observations of numismatic material and analysis of sources indicate that Roman coins could have had the function of a medium of exchange or payment in Andhra or, more broadly, India, but also played a bullion and prestigious role. The time of the influx of Roman money indicates that it was associated primarily with the period of the Satavahana Empire in Andhra. The essentially small number of registered Roman coins in relation to the territory and its role in trade indicates that the coins were only one, perhaps not a key element of Indo-Roman trade.

This is account of the first auction of rare magazines and newspapers organized at the Warsaw Academic Antiquarian Bookshop (Magazines and Newspapers) of the Publishing House Dom Książki in 1984. It offered over two thousand items, published in Poland and abroad, from the 18th until the 20th century.

Among the several crises that occurred in the 16th century, the famine crisis and high prices in the years 1569–1574 had exceptional significance, as its intensity, scope and duration far out-weighed other economic collapses of the century. Despite this, the course of events and the consequences have been of virtually no interest to historians over the years, which begs the question: why? As it seems, the events connected with the crises in question were overshadowed in Western historiography by other numerous and significant political events at the time, such as the Battle of Lepanto (1571) and the Night of St. Bartholomew in France (1572). In the Polish-‑Lithuanian state, in contrast, between 1569 and 1574, the famine and high prices coincided with a crisis of royal power and the state. This, indeed, drew the attention of historians, but only to political issues, among them the Polish‑Lithuanian union of 1569, the succession to the throne after the heirless Sigismund Augustus died, the first free election, religious disputes, the flight of King Henryk Walezy (Henry III), and the neighbouring wars, rather than to the social problems connected with the mass death of the poorest in the state, and the resulting economic problems. Therefore, in this article, the author synthesises the course of the famine crisis of 1569–1574 in the Polish‑Lithuanian state and hypothesises that the events and implications of this crisis largely preserved the mentality of the nobility in the following centuries and their dominance in the economic and political life of the Commonwealth. This crisis also influenced a choice of different path for development of the Commonwealth compared to other European countries. To clarify, the author does not claim to have exhausted the subject, and the article is intended to spur a discussion and further detailed research.

Exploring the drivers of changes in ecosystem services is crucial to maintain ecosystem functionality, especially in the diverse Central Citarum watershed. This study utilises the integrated valuation of ecosystem service and trade-offs (InVEST) model and multiscale geographically weighted regression (MGWR) model to examine ecosystem services patterns from 2006 to 2018. The InVEST is a hydrological model to calculate water availability and evaluate benefits provided by nature through simulating alterations in the amount of water yields driven by land use/cover changes. Economic, topographic, climate, and vegetation factors are considered, with an emphasis on their essential components. The presence of a geographical link between dependent and explanatory variables was investigated using a multiscale geographic weighted regression model. The MGWR model is employed to analyse spatial impacts. The integration of both models simplified the process and enhanced its understanding. The findings reveal the following patterns: 1) decreasing land cover and increasing ecosystem services demand in the watershed, along with a decline in water yield, e.g. certain sub-districts encounter water scarcity, while others have abundant water resources; 2) the impact of natural factors on water yield shifts along vegetation > climate > topography (2006) changes to climate > vegetation > topography (2018).