Network Connectivity Game

We investigate the cost allocation strategy associated with the problem of providing service /communication between all pairs of network nodes. There is a cost associated with each link and the communication between any pair of nodes can be delivered via paths connecting those nodes. The example of a cost efficient solution which could provide service for all node pairs is a (non-rooted) minimum cost spanning tree. The cost of such a solution should be distributed among users who might have conflicting interests. The objective of this paper is to formulate the above cost allocation problem as a cooperative game, to be referred to as a Network Connectivity (NC) game, and develop a stable and efficient cost allocation scheme. The NC game is related to the Minimum Cost Spanning Tree games and to the Shortest Path games. The profound difference is that in those games the service is delivered from some common source node to the rest of the network, while in the NC game there is no source and the service is established through the two-way interaction among all pairs of participating nodes. We formulate Network Connectivity (NC) game and construct an efficient cost allocation algorithm which finds some points in the core of the NC game. Finally, we discuss the Egalitarian Network Cost Allocation (ENCA) rule and demonstrate that it finds an additional core point

IoT pohjainen betonin kuivumisolosuhteiden hallinta uusien asuinrakennuskohteiden tuotantovaiheessa

Recently, moisture related problems, particularly in relatively new residential buildings, have drawn a significant amount of media attention. Consequently, numerous researches and studies have been conducted in order to detect, analyse, and prevent future moisture problems from occurring. Unwanted moisture in the structures has been found to cause both considerable financial losses and severe health issues due to potential growth of mold, dust mite presence and VOC emissions. There are many causes to the above-mentioned problems throughout the building life cycle, including inadequate design, negligent construction and inappropriate use and maintenance. One of the major single causes is construction moisture that is not properly controlled and removed during the construction phase. The aim of this Master’s thesis is to determine whether it is technically possible and financially feasible to actively steer the construction site management to maintain at all times indoor conditions that are optimal for drying of concrete with the help of real-time IoT-based monitoring technology, and additionally support or even replace current humidity measurement process. Secondary aim is to determine which wireless area network (WAN) is best suited for achieving the former aim, both from technical and financial point of view, taking into account the constantly changing construction environment conditions. The theory section is compiled as a literature survey containing previous studies and literature on concrete including the Finnish building code, the Building Information Ltd and the Confederation of Finnish Construction Industries (CFCI) the as the main source, due to the fact that the concreting conditions in Finland and other Nordic countries are rather challenging, also implying that the quality of Finnish concrete technology is very advanced. The empirical part consists of building, testing and installing the IoT-architecture on the pilot construction site, collecting, analysing and storing sensor data, and developing a web based application designed for the construction site management. The thesis proves that real-time control of drying conditions provides significant financial benefits by cutting down construction time, by optimizing the use of heating energy and by reducing the need for traditional moisture measurements. The case study also shows that the construction management is benefitting greatly from a supplementary mobile web application highlighting the importance of building physics in the drying process.Viime aikoina etenkin uudehkojen asuinrakennusten kosteus- ja homeongelmat ovat saaneet huomattavaa näkyvyyttä mediassa, minkä seurauksena lukuisia uusia tutkimuksia on tehty selvittääkseen ongelmien perimmäiset syyt sekä pystyäkseen ehkäisemään tulevia ongelmia. Kosteusvaurioiden syiksi on todettu mm. uusien energiamääräysten mukaiset erityisen haasteelliset arkkitehti-, rakenne- ja talotekniikkasuunnitelmat, rakennustuotannon ylikuumentuminen ja sitä kautta kasvanut riski työmaalla tapahtuviin virheisiin sekä vääränlainen käyttö ja ylläpito. Yksi isoimmista yksittäisistä syistä on kuitenkin rakennuskosteus eli rakennusmateriaalien kuten betonielementtien valmistuskosteus ja rakenteisiin rakennusaikana päässyt kosteus, jota pitäisi pystyä hallitsemaan nykyistä paremmin. Diplomityön tavoitteena on selvittää, voiko reaaliaikaisella, IoT-teknologiaan perustuvalla työmaan rakennusaikaisten ulko- ja sisäolosuhteiden seurannalla ja betonin kosteuden mittauksella aktiivisesti ohjata työmaan johtoa betonin kuivumiselle optimaalisten olosuhteiden ylläpitämisessä sekä täydentämään tai jopa mahdollisesti korvaamaan nykyistä kosteudenmittausprosessia. Toissijaisena tavoitteena on selvittää, mikä langaton tiedonsiirtoverkko sopii kyseisten tavoitteiden saavuttamisessa parhaiten, sekä tekniseltä toteutukseltaan että kustannustehokkuuden näkökulmasta, ottaen huomioon haastavat ja muuttuvat työmaaolosuhteet. Tutkimuksen teoreettinen osuus on toteutettu kirjallisuuskatsauksena. Tämän tutkimuksen lähteinä on käytetty pääasiassa Suomen rakentamismääräykokoelman, Rakennustiedon (RT), Betoniteollisuus Ry:n ja Betoniyhdistys Ry:n (BY) betonirakenteiden ohjeita ja määräyksiä, johtuen siitä, että Suomessa ja muissa pohjoismaissa rakennusolosuhteet ovat hyvin haastavat, mikä tarkoittaa myös sitä, että suomalainen betonitekniikka on laadullisesti hyvin korkealla tasolla. Tutkimuksen empiirinen osuus koostuu IoT-arkkitehtuurin rakentamisesta ja asentamisesta pilottityömaalle, sensorien datan keräämisestä, analyysistä ja talletuksesta sekä työmaahenkilöstölle tarkoitetun verkkopohjaisen applikaation kehittämisestä. Tutkimus osoittaa, että reaaliaikaisella kuivumisolosuhteiden seurannalla voidaan saavuttaa projektista riippuen hyvinkin merkittävää taloudellista hyötyä lyhentämällä rakennusvaiheen kestoa, tehostamalla lämmitysenergian käyttöä ja vähentämällä perinteisten kosteusmittausten määrää. Pilottiprojekti osoittaa, että työnjohto hyötyy selvästi applikaation käytöstä ja se auttaa ennen kaikkea nuoria ja vähemmän kokeneita työnjohtajia ymmärtämään työmaan rakennusfysiikan merkityksen betonin kuivumisprosessissa

On some cost allocation problems in communication networks

New technologies prompted an explosion in the development of communication networks. Modern network optimization techniques usually lead to a design of the most profitable, or the least cost network that will provide some service to customers. There are various costs and gains associated with building and using a communication network. Moreover, the involved multiple network users and/or owners possibly have conflicting objectives. However, they might cooperate in order to decrease their joint cost or increase their joint profit. Clearly, these individuals or organizations will support a globally \u27attractive\u27 solution(s) only if their expectations for a \u27fair share\u27 of the cost or profit are met. Consequently, providing network developers, users and owners with efficiently computable \u27fair\u27 cost allocation solution procedures is of great importance for strategic management. This work is an overview of some recent results (some already published as well as some new) in the development of cooperative game theory based mechanisms to efficiently compute \u27attractive\u27 cost allocation solutions for several important classes of communication networks

On Cost Allocation in Networks with Threshold Based Discounting

We study network design in which each pair of nodes can communicate via a direct link and the communication flow can be delivered through any path in the network. The cost of flow through each link is discounted if and only if the amount of flow exceeds certain threshold. This exploitation of economies of scale encourages the concentration of flows and use of relatively small number of links. Applications include telecommunications, airline traffic flow, and mail delivery networks. The cost of services delivered through such a network is distributed among its users who may be individuals or organizations with possibly conflicting interests. The cooperation between these users is essential for the exploitation of economies of scale. Consequently, there is a need to ensure a fair distribution of the cost of providing the service among network users. In order to describe this cost allocation problem we formulate the associated cooperative game, to be referred to as the threshold game. We then demonstrate that certain cost allocation solution (the core of the threshold game) can be efficiently applied to relatively ’large’ networks with threshold-based discounting

On strongly polynomial algorithms for some classes of quadratic programming problems

In this paper we survey some results concerning polynomial and/or strongly polynomial solvability of some classes of quadratic programming problems. The discussion on polynomial solvability of continuous convex quadratic programming is followed by a couple of models for quadratic integer programming which, due to their special structure, allow polynomial (or even strongly polynomial) solvability. The theoretical merit of those results stems from the fact that a running time (i.e. the number of elementary arithmetic operations) of a strongly polynomial algorithm is independent of the input size of the problem

Network cost allocation games based on threshold discounting

Consider networks in which each pair of nodes needs to communicate. The communication flow between any pair of nodes can be delivered through a direct link or via some connecting path in the network. By discounting the cost of flow through links for which the high flow volume is anticipated, network designers exploit economies of scale. This approach encourages the concentration of flows and use of relatively small number of links. This led to the design of well known hub networks and more recently hub-like networks. Applications include telecommunications, airline traffic flow, and mail delivery networks. The cost of services delivered through such networks is distributed among its users who may be individuals or organizations with possibly conflicting interests. The cooperation of these users is essential for the exploitation of economies of scale. Consequently, there is a need to find a fair distribution of the cost of providing the service among network users. In this paper, we present a survey of some recent results in the development of cooperative game theory based mechanisms to efficiently characterize cost allocation solutions for hub and hub-like networks. Specifically, we formulate the associated hub and hub-like network cost allocation games. Then, while paying special attention to users\u27 contribution to economies of scale, we demonstrate that some attractive cost allocation solutions, which provide users with the incentive to cooperate, can be efficiently computed

An application of a genetic algorithm for throughput optimization in non-broadcast WDM optical networks with regular topologies

We apply a genetic algorithm from Podnar and Skorin-Kapov [5] to a virtual topology design of a Wide-Area WDM Optical Network with regular topologies. Based on a given physical topology a virtual topology consisting of optical lightpaths is constructed. The objective is to minimize the maximal throughput, which implies balancing link loads and accommodating on-growing traffic requirements in a timely fashion. The genetic algorithm is applied to benchmark instances of regular topologies