The essence of this work is employment of IT and mathematical methods in development of remote applications with dynamically changing media. Analysis and practical use of methods are based on instances of internet games. The main groups and peculiarities of rapidly growing entertainment form – internet games – and programming technologies and languages used in development of such games are presented. Multiplayer multisession internet games with persistent world are analyzed. The main purpose of work is to highlight such games' dynamic aspects and implementing solutions. Differences and similarities of dynamics in real time games and turn-based games are highlighted with aim to integrate strength of both groups. Goals of work are analysis of methods and implementation of factors which influence game dynamics: user activity synchronization, persistent and changing game environment, data streaming. Implementation solutions are submitted in form of multiplayer real time internet game "Žvejyba".

As online video games rise in popularity, there has been a significant increase in fraudulent behavior and malicious activity. Numerous methods have been proposed to automate the identification and detection of such behaviors but most studies focused on situations with perfect prior knowledge of the gaming environment, particularly, in regards to the malicious behaviour being identified. This assumption is often too strong and generally false when it comes to real-world scenarios. For these reasons, it is useful to consider the case of incomplete information and combine techniques from machine learning and solution concepts from game theory that are better suited to tackle such settings, and automate the detection of anomalous behaviors. In this thesis, we focus on two major threats in competitive multiplayer games: intrusion and device compromises, and cheating and exploitation. The former is a knowledge-based anomaly detection, focused on understanding the technology and strategy being used by the attacker in order to prevent it from occurring. One of the major security concerns in cyber-security are Advanced Persistent Threats (APT). APTs are stealthy and constant computer hacking processes which can compromise systems bypassing traditional security measures in order to gain access to confidential information held in those systems. In online video games, most APT attacks leverage phishing and target individuals with fake game updates or email scams to gain initial access and steal user data, including but not limited to account credentials and credit card numbers. In our work, we examine the two player game called FlipIt to model covert compromises and stealthy hacking processes in partial observable settings, and show the efficiency of game theory concept solutions and deep reinforcement learning techniques to improve learning and detection in the context of fraud prevention. The latter defines a behavioral-based anomaly detection. Cheating in online games comes with many consequences for both players and companies; hence, cheating detection and prevention is an important part of developing a commercial online game. However, the task of manually identifying cheaters from the player population is unfeasible to game designers due to the sheer size of the player population and lack of test datasets. In our work, we present a novel approach to detecting cheating in competitive multiplayer games using tools from hybrid intelligence and unsupervised learning, and give proof-of-concept experimental results on real-world datasets.

Η παρούσα διπλωματική εργασία πραγματεύεται ένα παιχνίδι πολλών παικτών που παίζεται με συσκευές Android στην πόλη της Πάτρας. Το όνομα του παιχνιδιού είναι "Αόρατη Πόλη". / This thesis describes the development of a multiplayer game in android platform played in the city of Patras. The name of the game is "Invisible City".

Dans les jeux multijoueurs, où plusieurs joueurs participent à une même partie et communiquent entre eux à travers un réseau, les joueurs peuvent avoir des visions différentes du jeu en raison des délais de communication. Ceci engendre des incohérences encore plus importantes sur les réseaux mobiles tels que les réseaux 3G où les délais de communication peuvent atteindre plusieurs secondes. Des algorithmes doivent donc être mis en place pour maintenir la cohérence entre les joueurs. Ces algorithmes sont assez complexes et difficiles à programmer et mettre au point. Le but de cette thèse est de proposer une architecture logicielle qui découple la conception du jeu, de ses besoins de communication en proposant une infrastructure de communication qui pourra être interchangeable en fonction des technologies ; cette infrastructure prend la forme originale d'un composant de synchronisation. Ainsi, les conséquences des propriétés physiques du transport des informations pourront être plus ou moins masquées en intégrant dans cette infrastructure les algorithmes adéquats. / Multiplayer games users' have increased since the widespread use of the internet. Withthe arrival of rich portable devices and faster cellular wireless networks, multiplayer games on mobile phones and PDAs are becoming a reality. For multiplayer games to be playable, they should be highly interactive, fair and should have a consistent state for all the players. Because of the high wireless network latency and jitters, the issue of providing interactive games with consistent state across the network is non-trivial. In this thesis, we propose different approaches for achieving consistency in mobile multiplayer games in the face of high latency and large and variable jitters. Although absolute consistency is impossible to achieve because information takes time to travel from one place to another, we exploit the fact that strong consistency is not always required in the virtual world and can be relaxed in many cases. Our proposed approach uses the underlying network latency and the position of different objects in the virtual world to decide when to relax consistency and when to apply strong consistency mechanisms. We evaluate our approach by implementing these algorithms in J2ME based games played on mobile phones. The algorithms for consistency mechanism are very complex and are often intermixed with the game core logic's code, which makes it hard to program a game and to change its code in the future. We propose to separate the consistency mechanisms from the game logic and put them in a distributed component responsible for both consistency maintenance and communication over the network. We call this reusable component a Synchronization Medium.

In this thesis, we study parallelization of multiplayer games using software Transactional Memory (STM) support. We show that STM provides not only ease of programming, but also better scalability than achievable with state-of-the-art lock-based programming for this realistic high impact application. We evaluate and compare two parallel implementations of a simplified version (named SynQuake) of the popular game Quake. While in STM SynQuake support for maintaining consistency of each potentially complex game action is automatic, conservative locking of surrounding objects within a bounding-box for the duration of the game action is inherently needed in lock-based SynQuake. This leads to higher scalability of STM SynQuake versus lock-based SynQuake due to increased false sharing in the latter. Task assignment to threads has a second-order effect on scalability of STM-SynQuake, impacting the application's true sharing patterns. We show that a locality-aware task assignment provides the best trade-off between load balancing and conflict reduction.

In this thesis, we study parallelization of multiplayer games using software Transactional Memory (STM) support. We show that STM provides not only ease of programming, but also better scalability than achievable with state-of-the-art lock-based programming for this realistic high impact application. We evaluate and compare two parallel implementations of a simplified version (named SynQuake) of the popular game Quake. While in STM SynQuake support for maintaining consistency of each potentially complex game action is automatic, conservative locking of surrounding objects within a bounding-box for the duration of the game action is inherently needed in lock-based SynQuake. This leads to higher scalability of STM SynQuake versus lock-based SynQuake due to increased false sharing in the latter. Task assignment to threads has a second-order effect on scalability of STM-SynQuake, impacting the application's true sharing patterns. We show that a locality-aware task assignment provides the best trade-off between load balancing and conflict reduction.

<p>The focus of this dissertation is on large-scale and long-running networked real-time multiplayer games. In this type of games, each player controls one or many entities, which interact in a shared virtual environment. Three attributes - scalability, security, and fault tolerance - are considered essential for this type of games. The normal approaches for building this type of games, using a client/server or peer-to-peer architecture, fail in achieving all three attributes. We propose a server-network architecture that supports these attributes. In this architecture, a cluster of servers collectively manage the game state and each server manages a separate region of the virtual environment. We discuss how the architecture can be extended using proxies, and we compare it to other similar architectures. Further, we investigate how a distributed database management system can support the proposed architecture. Since efficiency is very important in this type of games, some properties of traditional database systems must be relaxed. We also show how methods for increasing scalability, such as interest management and dead reckoning, can be implemented in a database system. Finally, we suggest how the proposed architecture can be validated using a simulation of a large-scale game.</p>

The thesis deals with market models with random inputs represented by the newsvendor problem for which the randomness is given through a random number of customers. Presented work is divided into three chapters. In the first chapter we present the elementar newsvendor problem as stochastic programming problem with a fixed recourse. In the second chapter we present the multiplayer game theory adapted to the newsvendors problem. Moreover, in the second chapter we extend the problem by the second newsvendor on the market and in the third chapter we generalize the problem for n newsvendors on the market. We deal with the situations that arise in the chapters two and three from the game theory point of view and we study characteristics of a Nash equilibrium. Presented theory is demonstrated on illustrative examples in the ends of the two last chapters. 1

The focus of this dissertation is on large-scale and long-running networked real-time multiplayer games. In this type of games, each player controls one or many entities, which interact in a shared virtual environment. Three attributes - scalability, security, and fault tolerance - are considered essential for this type of games. The normal approaches for building this type of games, using a client/server or peer-to-peer architecture, fail in achieving all three attributes. We propose a server-network architecture that supports these attributes. In this architecture, a cluster of servers collectively manage the game state and each server manages a separate region of the virtual environment. We discuss how the architecture can be extended using proxies, and we compare it to other similar architectures. Further, we investigate how a distributed database management system can support the proposed architecture. Since efficiency is very important in this type of games, some properties of traditional database systems must be relaxed. We also show how methods for increasing scalability, such as interest management and dead reckoning, can be implemented in a database system. Finally, we suggest how the proposed architecture can be validated using a simulation of a large-scale game.

This thesis focuses on which kinds of aspects that would be extra important when two or more persons are collaboratively navigating a single character in a game world. With help of interaction design methods during this process, such as literature researches and usability tests, a low-fidelity and a mid-fidelity prototype were created to find these aspects. In the tests, I also used a high-fidelity game to compare my prototypes with. The conclusion and discussion in this thesis presents different sorts of new ideas and possibilities concerning the different aspects that could lead to developing new interesting games with collaborative navigation.