Bandwidth Trading: A Comparison of the Combinatorial and Multicommodity Approach, Journal of Telecommunications and Information Technology, 2010, nr 2

Since the telecommunication market becomes more complex and dynamic, a strong need for a new, efficient and flexible bandwidth trading mechanisms appears. We believe that good mechanisms, that allow effective and fair allocation of bandwidth between market participants will help to develop the real competitive bandwidth market. In this paper we compare two different double-sided bandwidth auction mechanisms, that seem to be well suited approaches for trading indivisible units of bandwidth: combinatorial auction c-SeBiDA and multicommodity mechanism BACBR-I. The c-SeBiDA mechanism considers two types of commodities: inter-node links and paths consisting of particular links. Market partici- pants may bid a single link, or a bundle of links, constituting a specific path. The BACBR-I mechanism is a multicommodity exchange model, that allows bidders to place buy offers not only for individual or bundled links, but rather for end-to-end connections. Therefore, it is the decision model that allocates the most efficient links to connections. We run a large set of experiments to test the allocation and computational efficiency obtained under both approaches

Multicommodity Auction Model for Indivisible Network Resource Allocation, Journal of Telecommunications and Information Technology, 2008, nr 4

In this paper we present the multicommodity auction model BCBT-I that allocates indivisible network resources among bidders. The approach can be considered as a generalization of the basic multicommodity model for balancing communication bandwidth trade (BCBT). The BCBT model assumes that offers concerning inter-node links and point-to-point bandwidth demands can be realized partially. However, in the real-world trade there might be a need to include capacity modularity in the market balancing process. Thus we state the model for balancing communication bandwidth trade that takes into account the indivisibility of traded bandwidth modules. This requires to solve a mixed integer problem and increases computational complexity. Furthermore, the pricing issue appears nontrivial, as the dual prices cannot be longer used to set fair, competitive market prices. For clearing the market, we examine the multicommodity pricing mechanizm based on differentiation of buy and sell market prices

Model for Balancing Aggregated Communication Bandwidth Resources, Journal of Telecommunications and Information Technology, 2009, nr 3

In this paper we present a multicommodity bandwidth exchange model for balancing aggregated communication bandwidth resources (BACBR) that allows us to aggregate similar offers. In this model offers submitted to sell (or buy) the same, similar, or equivalent network resources (or demands for end-to-end connections) are aggregated into single commodities. BACBR model is based on the balancing communication bandwidth trade (BCBT) model. It requires much less variables and constraints then original BCBT, however the outcomes need to be disaggregated. The general model for disaggregation is also given in the paper

Improved procedures of Sc(OH)3 precipitation and UTEVA extraction for 44Sc separation

BACKGROUND: 44Sc is becoming attractive as a PET radionuclide due to its decay characteristics. It can be produced from 44Ca present in natural calcium with 2.08% abundance. MATERIALS AND METHODS: The targets were mostly prepared from natural CaCO3 or metallic calcium in the form of pellets. After irradiation they were dissolved in 3 M hydrochloric acid and 44Sc was separated from excess of calcium by precipitation of scandium hydroxide using ammonia. Alternatively, targets were dissolved in 11 M hydrochloric acid and 44Sc was separated by extraction chromatography on UTEVA resin. As the next step, in both processes 44Sc was further purified on a cation exchange resin. Initially, the separation procedures were developed with 46Sc as a tracer. Gamma spectrometry with a high purity germanium detector was used to determine the separation efficiency. Finally, the CaCO3 pellet with 99.2% enrichment in 44Ca was activated with protons via 44Ca(p,n)44Sc nuclear reaction. RESULTS: Altogether twenty two irradiations and separations were performed. The working procedures were developed and the quality of separated 44Sc solution was confirmed by radiolabeling of DOTATATE. The chemical purity of the product was sufficient for preclinical experiments. At the end of around 1 hour proton beam irradiation of CaCO3 pellet with 99.2% enrichment in 44Ca the obtained radioactivity of 44Sc was more than 4.8 GBq. CONCLUSION: 44Sc can be produced inexpensively with adequate yields and radionuclidic purity via 44Ca(p,n)44Sc nuclear reaction in small cyclotrons. The recovery yield in both investigated separation methods was comparable and amounted above 90%. The obtained 44Sc was pure in terms of radionuclide and chemical purity, as shown by the results of peptide radiolabeling

Mechanizm rozliczeń oparty na rekompensatach do zastosowania na rynkach z ofertami nieliniowymi

A compensation-based pricing scheme is a market clearing mechanism that may be applied when a uniform, linear pricing scheme cannot support equilibrium allocations in the auction markets. We analyze extensions of our previously proposed pricing scheme [14] to include various possible representations of bids that reflect some non-convex costs and constraints. We conclude with a discussion on directions for future research.Rozważany w pracy model rozliczania obrotu oparty na rekompensatach jest odpowiednim narzędziem wyceny na rynkach giełdowych w sytuacji, gdy nie można wyznaczyć jednolitych cen równowagi. Sytuacja taka ma miejsce np. na bilansującym rynku energii elektrycznej, gdy w procesie bilansowania rynku są uwzględniane indywidualne ograniczenia i nieliniowe koszty jednostek wytwórczych. W pracy rozważono model wyceny opracowany przez autorów w [14], analizując jego właściwości istotne z perspektywy projektowania mechanizmów rynkowych (indywidualna racjonalność, neutralność finansowa, efektywność). W głównej części pracy przedstawiono szersze zastosowania modelu do różnych typów ofert (schodkowe, przedziałami liniowe) oraz wprowadzanych ograniczeń (czasy rozruchu i odstawienia, koszty rozruchu i odstawienia, koszty stałe). Ważnym obszarem zastosowań mechanizmu mogą być również giełdy energii dopuszczające składanie ofert blokowych. Pokazano schematy modelowania zadania rozliczania obrotu w postaci zadania MILP dla różnych typów rynków. Poszczególne mozliwośći zastosowania zilustrowano na przykładach. W podsumowaniu zaprezentowano dalsze kierunki rozwoju badań nad modelami wyceny na rynkach z ograniczeniami

Paper Multicommodity Auction Model for Indivisible Network Resource Allocation

Abstract—In this paper we present the multicommodity auction model BCBT-I that allocates indivisible network resources among bidders. The approach can be considered as a generalization of the basic multicommodity model for balancing communication bandwidth trade (BCBT). The BCBT model assumes that offers concerning inter-node links and point-topoint bandwidth demands can be realized partially. However, in the real-world trade there might be a need to include capacity modularity in the market balancing process. Thus we state the model for balancing communication bandwidth trade that takes into account the indivisibility of traded bandwidth modules. This requires to solve a mixed integer problem and increases computational complexity. Furthermore, the pricing issue appears nontrivial, as the dual prices cannot be longer used to set fair, competitive market prices. For clearing the market, we examine the multicommodity pricing mechanism based on differentiation of buy and sell market prices

Paper Model for Balancing Aggregated Communication Bandwidth Resources

Abstract—In this paper we present a multicommodity bandwidth exchange model for balancing aggregated communication bandwidth resources (BACBR) that allows us to aggregate similar offers. In this model offers submitted to sell (or buy) the same, similar, or equivalent network resources (or demands for end-to-end connections) are aggregated into single commodities. BACBR model is based on the balancing communication bandwidth trade (BCBT) model. It requires much less variables and constraints then original BCBT, however the outcomes need to be disaggregated. The general model for disaggregation is also given in the paper