Public Congestion Network Situations, and Related Games

This paper analyzes congestion effects on network situations from a cooperative game theoretic perspective. In network situations players have to connect themselves to a source. Since we consider publicly available networks any group of players is allowed to use the entire network to establish their connection. We deal with the problem of finding an optimal network, the main focus of this paper is however to discuss the arising cost allocation problem. For this we introduce two different transferable utility cost games. For concave cost functions we use the direct cost game, where coalition costs are based on what a coalition can do in absence of other players. This paper however mainly discusses network situations with convex cost functions, which are analyzed by the use of the marginal cost game. In this game the cost of a coalition is defined as the additional cost it induces when it joins the complementary group of players. We prove that this game is concave. Furthermore, we define a cost allocation by means of three egalitarian principles, and show that this allocation is an element of the core of the marginal cost game. These results are extended to a class of continuous network situations and associated games.Congestion;network situations;cooperative games;public

Public Congestion Network Situations, and Related Games

This paper analyzes congestion effects on network situations from a cooperative game theoretic perspective. In network situations players have to connect themselves to a source. Since we consider publicly available networks any group of players is allowed to use the entire network to establish their connection. We deal with the problem of finding an optimal network, the main focus of this paper is however to discuss the arising cost allocation problem. For this we introduce two different transferable utility cost games. For concave cost functions we use the direct cost game, where coalition costs are based on what a coalition can do in absence of other players. This paper however mainly discusses network situations with convex cost functions, which are analyzed by the use of the marginal cost game. In this game the cost of a coalition is defined as the additional cost it induces when it joins the complementary group of players. We prove that this game is concave. Furthermore, we define a cost allocation by means of three egalitarian principles, and show that this allocation is an element of the core of the marginal cost game. These results are extended to a class of continuous network situations and associated games.

Axiomatizations Of Symmetrically Weighted Solutions

If the excesses of the coalitions in a transferable utility game are weighted, then we show that the arising weighted modifications of the well-known (pre)nucleolus and (pre)kernel satisfy the equal treatment property if and only if the weight system is symmetric in the sense that the weight of a subcoalition of a grand coalition may only depend on the grand coalition and the size of the subcoalition. Hence, the symmetrically weighted versions of the (pre)nucleolus and the (pre)kernel are symmetric, i.e., invariant under symmetries of a game. They may, however, violate anonymity, i.e., they may depend on the names of the players. E.g., a symmetrically weighted nucleolus may assign the classical nucleolus to one game and the per capita nucleolus to another game. We generalize Sobolev’s axiomatization of the prenucleolus and its modification for the nucleolus as well as Peleg’s axiomatization of the prekernel to the symmetrically weighted versions. Only the reduced games have to be replaced by suitably modified reduced games whose definitions may depend on the weight system. Moreover, it is shown that a solution may only satisfy the mentioned sets of modified axioms if the weight system is symmetric

Bankruptcy and the Per Capita Nucleolus

Abstract: This article characterizes the per capita nucleolus for bankruptcy games as a bankruptcy rule. This rule, called the cligths rule, is based on the wellknown constrained equal awards principle. The essential feature of the rule however is that, for each bankruptcy problem, it takes into account a vector of clights. These clights only depend on the vector of claims while the height of the estate determines whether the clights should be interpreted as modified claims or as rights. Finally, it is seen that both the clights rule and the Aumann-Maschler rule can be captured within the family of so-called claim and right rules.

Cake Cutting Algorithms for Piecewise Constant and Piecewise Uniform Valuations

Cake cutting is one of the most fundamental settings in fair division and mechanism design without money. In this paper, we consider different levels of three fundamental goals in cake cutting: fairness, Pareto optimality, and strategyproofness. In particular, we present robust versions of envy-freeness and proportionality that are not only stronger than their standard counter-parts but also have less information requirements. We then focus on cake cutting with piecewise constant valuations and present three desirable algorithms: CCEA (Controlled Cake Eating Algorithm), MEA (Market Equilibrium Algorithm) and CSD (Constrained Serial Dictatorship). CCEA is polynomial-time, robust envy-free, and non-wasteful. It relies on parametric network flows and recent generalizations of the probabilistic serial algorithm. For the subdomain of piecewise uniform valuations, we show that it is also group-strategyproof. Then, we show that there exists an algorithm (MEA) that is polynomial-time, envy-free, proportional, and Pareto optimal. MEA is based on computing a market-based equilibrium via a convex program and relies on the results of Reijnierse and Potters [24] and Devanur et al. [15]. Moreover, we show that MEA and CCEA are equivalent to mechanism 1 of Chen et. al. [12] for piecewise uniform valuations. We then present an algorithm CSD and a way to implement it via randomization that satisfies strategyproofness in expectation, robust proportionality, and unanimity for piecewise constant valuations. For the case of two agents, it is robust envy-free, robust proportional, strategyproof, and polynomial-time. Many of our results extend to more general settings in cake cutting that allow for variable claims and initial endowments. We also show a few impossibility results to complement our algorithms.Comment: 39 page

The Least-core and Nucleolus of Path Cooperative Games

Cooperative games provide an appropriate framework for fair and stable profit distribution in multiagent systems. In this paper, we study the algorithmic issues on path cooperative games that arise from the situations where some commodity flows through a network. In these games, a coalition of edges or vertices is successful if it enables a path from the source to the sink in the network, and lose otherwise. Based on dual theory of linear programming and the relationship with flow games, we provide the characterizations on the CS-core, least-core and nucleolus of path cooperative games. Furthermore, we show that the least-core and nucleolus are polynomially solvable for path cooperative games defined on both directed and undirected network

Kokemuksia Oman muotoinen koti -hankkeesta nuorten silmin

Opinnäytetyön tilaaja on Helsingin kaupungin nuorisoasiainkeskuksen Oman muotoinen koti -hanke. Hanke on aloitettu 2015 ja se tarjoaa nuorille eri asumiskokeilujen avulla ratkaisua haastaviin asumistilanteisiin Helsingissä. Oman muotoinen koti -hankkeessa nuoret muuttivat 2017 vuoden alussa asumaan Kannelmäkeen. Asunnon lisäksi nuorille avautui mahdollisuus tehdä töitä 20 tuntia kuukaudessa yhdessä mietittyjen tehtävien parissa. Opinnäytetyön idea oli seurata neljän nuoren alkuvaihetta Oman muotoinen koti -hankkeessa. Opinnäytetyöni tavoite oli keskittyä nuorten kokemusten taltiointiin hankkeen edetessä, mistä saatu tieto auttaisi hankkeen kehittämisessä tilaajaa. Sain tilaajalta vapaat kädet opinnäytetyön toteuttamiseen. Valitsin nuorten kokemusten taltioimiseen teemahaastattelun menetelmän. Haastateltavien keski-ikä oli 20 vuotta, joista osa oli maahanmuuttajataustaisia ja osa kantasuomalaisia. Kaikki haastateltavat olivat erilaisia, tein haastatteluun kysymysrungon, mutta annoin tilaa haastattelussa nuorille kertoa valitsemasta aiheesta enemmän. Äänitin haastattelut ja litteroin ne. Haastattelun teemat vaihtelivat haastateltavan kanssa. Vaikka kysymykset olivat samat, tunsi osa nuorista tarvetta puhua enemmän toisesta teemasta. Tein haastattelut hankkeen alkuvaiheessa, joten haastattelujen tulokset puhuvat vain hankkeen alkuvaiheen tunnelmista. Opinnäytetyön teoreettisessa viitekehyksessä käsittelen asunnottomuuden lisäksi nuorten työllisyyttä. Pohdin mikä motivoi nuoria työllistymiseen ja mitkä keinot auttavat nuoria löytämään sopivaa työtä ja mitkä asiat voivat vaikuttaa nuorten työllistymiseen. Aineiston analyysiosiossa avaan nuorten ajatuksia hankkeesta ja työnteosta. Yhdistän teoreettista viitekehystä omaan pohdintaan. Oman muotoinen koti hankkeen alkuvaiheen aineiston analyysin perusteella, hankkeelle on kova tarve ja sitä olisi hyvä laajentaa isommaksi eri puolille pääkaupunkiseutua. Hanke tukee nuorten hankalaa asumistilannetta ja työllistymistä alati muuttuvassa työelämässä.The thesis focuses on City of Helsinki’s youth Departments Home That Fits Project. The project started at the beginning of 2015 and its objective is to provide solution for the housing crisis among the youth population in Helsinki. Home That Fits project’s youth moved to shared apartment in Kannelmäki at the beginning of 2017. Apart from housing the youth were provided with opportunity to work 20 hours a month in a agreed contract between all the partners involved. The thesis goal was to follow four young people in the project’s early stage. The main focus was to understand on how the project can be develop through the experiences of the young participants in the Home That Fits project. From the young people’s experiences I did choose with the cooperation of the parties involved a particular themes that we could base our questions on. The interviewee’s average age was early 20’s. All the participants shared their experiences differently. The interview’s theme changed from time to time although the questions stayed the same. Some of the youth felt the need to talk more about other subject than the agreed themes. The interviews were conducted at the early stages of the project. Therefore the results are based on that. The Thesis theory part deals with the youth's employment: What motivates young people to seek employment , what are the mechanisms that have been created to help the youth find the right work and the issues that can affect youth employment. The findings shows that there is a certain need for Home That Fits project in the Helsinki area of Kannelmäki and it could expand to other parts of Helsinki metropolitan area

The matter of complex anti-matter: the portrayal and framing of physics in Dutch newspapers

Physics is often perceived as difficult, but there has been little research on how physics is reported in the media. In this two-stage content analysis, we examine the portrayal of physics in five major Dutch newspapers. Results show that astronomy and astrophysics is the most prominent field. Furthermore, newspaper articles are triggered almost equally by scientific and non-scientific events. Finally, the majority of described physics concepts are framed as difficult, but journalists do provide explanations for them.Science Communication and Societ

Body mass index and extent of MRI-detected inflammation: opposite effects in rheumatoid arthritis versus other arthritides and asymptomatic persons

Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas