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.
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.
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 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.
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.
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.
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.