Preoccupied by the past - the case of Estonia's Museum of Occupations

The nation is born out of the resistance, ideally without external aid, of its nascent citizens against oppression [...] An effective founding struggle should contain memorable massacres, atrocities, assassinations and the like, which serve to unite and strengthen resistance and render the resulting victory the more justified and the more fulfilling. They also can provide a focus for a "remember the x atrocity" historical narrative.(1

A Very Large Area Network (VLAN) knowledge-base applied to space communication problems

This paper first describes a hierarchical model for very large area networks (VLAN). Space communication problems whose solution could profit by the model are discussed and then an enhanced version of this model incorporating the knowledge needed for the missile detection-destruction problem is presented. A satellite network or VLAN is a network which includes at least one satellite. Due to the complexity, a compromise between fully centralized and fully distributed network management has been adopted. Network nodes are assigned to a physically localized group, called a partition. Partitions consist of groups of cell nodes with one cell node acting as the organizer or master, called the Group Master (GM). Coordinating the group masters is a Partition Master (PM). Knowledge is also distributed hierarchically existing in at least two nodes. Each satellite node has a back-up earth node. Knowledge must be distributed in such a way so as to minimize information loss when a node fails. Thus the model is hierarchical both physically and informationally

Covert Channels in SIP for VoIP signalling

In this paper, we evaluate available steganographic techniques for SIP (Session Initiation Protocol) that can be used for creating covert channels during signaling phase of VoIP (Voice over IP) call. Apart from characterizing existing steganographic methods we provide new insights by introducing new techniques. We also estimate amount of data that can be transferred in signalling messages for typical IP telephony call.Comment: 8 pages, 4 figure

Misclassification of game traffic based on port numbers: A case study using enemy territory

The identification of game traffic in the Internet is very useful for a number of tasks. For trend analysis it is important to find out how much game traffic is in the Internet and how much traffic certain games contribute. To provide better than best effort QoS for game traffic in the network it is necessary to identify game traffic before it can be prioritised. Traditionally, network applications have been classified based on port numbers. It has been argued that purely relying on port numbers does result in significant number of unidentified flows for applications such as peer-to-peer file sharing and game traffic. While this has already been shown for peer-to-peer traffic no such studies exist for game traffic. In this paper we focus on one particular game and estimate how much of the traffic cannot be identified when solely relying on port number based identification. We find that the number of game flows using non- default port numbers is significant. Our evaluation is based on real traffic captured at clients and public game servers

Magnetic correlations of the quasi-one-dimensional half-integer spin-chain antiferromagnets SrM2M_2V2_2O8_8 (MM = Co, Mn)

Magnetic correlations of two iso-structural quasi-one-dimensional (1D) antiferromagnetic spin-chain compounds Sr$M_2$V$_2$O$_8$ ($M$ = Co, Mn) have been investigated by magnetization and powder neutron diffraction. Two different collinear antiferromagnetic (AFM) structures, characterized by the propagation vectors, $k$ = (0 0 1) and $k$ = (0 0 0), have been found below $\sim$ 5.2 K and $\sim$ 42.2 K for the Co- and Mn-compounds, respectively. For the Mn-compound, AFM chains (along the $c$ axis) order ferromagnetically within the $ab$ plane, whereas, for the Co-compound, AFM chains order ferro-/antiferromagnetically along the $a/b$ direction. The critical exponent study confirms that the Co- and Mn-compounds belong to the Ising and Heisenberg universality classes, respectively. For both compounds, short-range spin-spin correlations are present over a wide temperature range above $T_N$. The reduced ordered moments at base temperature (1.5 K) indicate the presence of quantum fluctuations in both compounds due to the quasi-1D magnetic interactions.Comment: 14 pages, 10 figures, 9 table

Colloidal crystal growth at externally imposed nucleation clusters

We study the conditions under which and how an imposed cluster of fixed colloidal particles at prescribed positions triggers crystal nucleation from a metastable colloidal fluid. Dynamical density functional theory of freezing and Brownian dynamics simulations are applied to a two-dimensional colloidal system with dipolar interactions. The externally imposed nucleation clusters involve colloidal particles either on a rhombic lattice or along two linear arrays separated by a gap. Crystal growth occurs after the peaks of the nucleation cluster have first relaxed to a cutout of the stable bulk crystal.Comment: 4 pages, accepted for publication in Phys. Rev. Let

Evaluating machine learning algorithms for automated network application identification

The identification of network applications that create traffic flows is vital to the areas of network management and surveillance. Current popular methods such as port number and payload-based identification are inadequate and exhibit a number of shortfalls. A potential solution is the use of machine learning techniques to identify network applications based on payload independent statistical features. In this paper we evaluate and compare the efficiency and performance of different feature selection and machine learning techniques based on flow data obtained from a number of public traffic traces. We also provide insights into which flow features are the most useful. Furthermore, we investigate the influence of other factors such as flow timeout and size of the training data set. We find significant performance differences between different algorithms and identify several algorithms that provide accurate (up to 99% accuracy) and fast classification

Minimally-intrusive frequent round trip time measurements using Synthetic Packet-Pairs

Accurate and frequent round trip time (RTT) measurements are important in testbeds and operational networks. Active measurement techniques inject probe packets that may modify the behaviour of the observed network and may produce misleading RTT estimates if the network handles probe packets differently to regular packets. Previous passive measurement techniques address these issues, but require precise time synchronisation or are limited to certain traffic types. We introduce Synthetic Packet-Pairs (SPP), a novel passive technique for RTT measurement. SPP provides frequently updated RTT measurements using any network traffic already present in the network without the need for time synchronisation. SPP accurately measures the RTT experienced by any application's traffic, even applications that do not exhibit symmetric client-server packet exchanges. We experimentally demonstrate the advantages of SPP

Sampling schemes for validating service level agreements

Level Agreements (SLAs) specify the network Quality of Service (QoS) that providers are expected to deliver. Providers have to verify if the actual quality of the network traffic complies with the SLA. Ideally this should be done without introducing significant additional network load and the operational costs should be small. In this paper we propose a novel approach for the passive validation of SLAs based on direct samples of the customer traffic. The SLA contains pre-defined thresholds for QoS metrics, the maximum violation proportion and accuracy boundaries. We model the validation problem as proportion estimation of non-conformant traffic. Then we compare different sampling schemes according to their sampling errors and present a novel solution for estimating the error prior to the sampling. Finally we derive a solution for finding the optimum sample rate based on the SLA parameters