Cryptographic Energy Costs are Assumable in Ad Hoc Networks

Performance of symmetric and asymmetriccryptography algorithms in small devices is presented. Both temporaland energy costs are measured and compared with the basicfunctional costs of a device. We demonstrate that cryptographicpower costs are not a limiting factor of the autonomy of a deviceand explain how processing delays can be conveniently managedto minimize their impact.

Review of Robust Cooperative Spectrum Sensing Techniques for Cognitive Radio Networks

Cognitive radio networks sense spectrum occupancy and manage themselvesto operate in unused bands without disturbing licensed users. The detection capability of aradio system can be enhanced if the sensing process is performed jointly by a group of nodesso that the effects of wireless fading and shadowing can be minimized. However, taking acollaborative approach poses new security threats to the system as nodes can report falsesensing data to reach a wrong decision. This paper makes a review of secure cooperativespectrum sensing in cognitive radio networks. The main objective of these protocols is toprovide an accurate resolution about the availability of some spectrum channels, ensuring thecontribution from incapable users as well as malicious ones is discarded. Issues, advantagesand disadvantages of such protocols are investigated and summarized.

Security, Privacy and Anonymity in Legal Distribution of Copyrighted Multimedia Content over Peer-to-Peer Networks: A Brief Overview

Peer-reviewed

Secure and Anonymous Multimedia Content Distribution in Peer-to-Peer Networks

Peer-reviewed

The effects of social networks on work-team effectiveness

This is a study of team social networks, their antecedents and outcomes. In focusing attention on the structural configuration of the team this research contributes to a new wave of thinking concerning group social capital. The research site was a random sample of Finnish work organisations. The data consisted of 499 employees in 76 teams representing 48 different organisations. A systematic literature review and quantitative methods were used in conducting the research: the former primarily to establish the current theoretical position on the relationships among the variables and the latter to test these relationships. Social network analysis was the primary method used in identifying the social-network relations among the work-team members. The first and key contribution of this study is that it relates the structuralnetwork properties of work teams to behavioural outcomes, attitudinal outcomes and, ultimately, team performance. Moreover, it shows that addressing attitudinal outcomes is also important in terms of team performance; attitudinal outcomes (team identity) mediated the relationship between the team’s performance and its social network. The second contribution is that it examines the possible antecedents of the social structure. It is thus one response to Salancik’s (1995) call for a network theory in that it explains why certain network characteristics exist. Itdemonstrates that irrespective of whether or not a team is heterogeneous in terms of age or gender, educational diversity may protect it from centralisation. However, heterogeneity in terms of gender turned out to have a negative impact on density. Thirdly, given the observation that the benefits of (team) networks are typically theorised and modelled without reference to the nature of the relationships comprising the structure, the study directly tested whether team knowledge mediated the effects of instrumental and expressive network relationships on team performance. Furthermore, with its focus on expressive networks that link the workplace to a more informal world, which have been rather neglected in previous research, it enhances knowledge of teams andnetworks. The results indicate that knowledge sharing fully mediates the influence of complementarities between dense and fragmented instrumental network relationships, thus providing empirical validation of the implicit understanding that networks transfer knowledge. Fourthly, the study findings suggest that an optimal configuration of the work-team social-network structure combines both bridging and bonding social relationships.

Strategic Development of Electricity Distribution Networks – Concept and Methods

Strategic development of distribution networks plays a key role in the asset management in electricity distribution companies. Owing to the capital-intensive nature of the field and longspan operations of companies, the significance of a strategy is emphasised. A well-devised strategy combines awareness of challenges posed by the operating environment and the future targets of the distribution company. Economic regulation, ageing infrastructure, scarcity of resources and tightening supply requirements with challenges created by the climate change put a pressure on the strategy work. On the other hand, technology development related to network automation and underground cabling assists in answering these challenges. This dissertation aims at developing process knowledge and establishing a methodological framework by which key issues related to network development can be addressed. Moreover, the work develops tools by which the effects of changes in the operating environment on the distribution business can be analysed in the strategy work. To this end, the work discusses certain characteristics of the distribution business and describes the strategy process at a principle level. Further, the work defines the subtasks in the strategy process and presents the key elements in the strategy work and long-term network planning. The work delineates the factors having either a direct or indirect effect on strategic planning and development needs in the networks; in particular, outage costs constitute an important part of the economic regulation of the distribution business, reliability being thus a key driver in network planning. The dissertation describes the methodology and tools applied to cost and reliability analyses in the strategy work. The work focuses on determination of the techno-economic feasibility of different network development technologies; these feasibility surveys are linked to the economic regulation model of the distribution business, in particular from the viewpoint of reliability of electricity supply and allowed return. The work introduces the asset management system developed for research purposes and to support the strategy work, the calculation elements of the system and initial data used in the network analysis. The key elements of this asset management system are utilised in the dissertation. Finally, the study addresses the stages of strategic decision-making and compilation of investment strategies. Further, the work illustrates implementation of strategic planning in an actual distribution company environment.

Time-series forecasting of pollutant concentration levels using particle swarm optimization and artificial neural networks

This study evaluates the application of an intelligent hybrid system for time-series forecasting of atmospheric pollutant concentration levels. The proposed method consists of an artificial neural network combined with a particle swarm optimization algorithm. The method not only searches relevant time lags for the correct characterization of the time series, but also determines the best neural network architecture. An experimental analysis is performed using four real time series and the results are shown in terms of six performance measures. The experimental results demonstrate that the proposed methodology achieves a fair prediction of the presented pollutant time series by using compact networks.

Garlic viral complex: identification of Potyviruses and Carlavirus in Central Brazil

Garlic viruses often occur in complex infections in nature. In this study, a garlic virus complex, collected in fields in Brazil, was purified. RT-PCR was performed using specific primers designed from the consensus regions of the coat protein genes of Onion yellow dwarf virus, a garlic strain (OYDV-G) and Leek yellow stripe virus (LYSV). cDNA of Garlic common latent virus (GCLV) was synthesized using oligo-dT and random primers. By these procedures individual garlic virus genomes were isolated and sequenced. The nucleotide sequence analysis associated with serological data reveals the presence of two Potyvirus OYDV-G and LYSV, and GCLV, a Carlavirus, simultaneously infecting garlic plants. Deduced amino acid sequences of the Brazilian isolates were compared with related viruses reported in different geographical regions of the world. The analysis showed closed relations considering the Brazilian isolates of OYDV-G and GCLV, and large divergence considering LYSV isolate. The detection of these virus species was confirmed by specific reactions observed when coat protein genes of the Brazilian isolates were used as probes in dot-blot and Southern blot hybridization assays. In field natural viral re-infection of virus-free garlic was evaluated.

Description of epidemics of coffee rust with neural networks

The objective of this paper was to evaluate the potential of neural networks (NN) as an alternative method to the basic epidemiological approach to describe epidemics of coffee rust. The NN was developed from the intensities of coffee (Coffea arabica) rust along with the climatic variables collected in Lavras-MG between 13 February 1998 and 20 April 2001. The NN was built with climatic variables that were either selected in a stepwise regression analysis or by the Braincel® system, software for NN building. Fifty-nine networks and 26 regression models were tested. The best models were selected based on small values of the mean square deviation (MSD) and of the mean prediction error (MPE). For the regression models, the highest coefficients of determination (R²) were used. The best model developed with neural networks had an MSD of 4.36 and an MPE of 2.43%. This model used the variables of minimum temperature, production, relative humidity of the air, and irradiance 30 days before the evaluation of disease. The best regression model was developed from 29 selected climatic variables in the network. The summary statistics for this model were: MPE=6.58%, MSE=4.36, and R²=0.80. The elaborated neural networks from a time series also were evaluated to describe the epidemic. The incidence of coffee rust at four previous fortnights resulted in a model with MPE=4.72% and an MSD=3.95.

Operation and Maintenance Security Service for OSS-RC networks

Security issues in telecommunication networks have become more important due to the development of the industry. The number of network elements and services has increased in the radio network as in the core network side, which has increased the number of security related issues. Ericsson has developed an OSS-RC product for operation and maintenance porpoises into the telecommunication networks. OSS-RC is used in a number of telecommunications operators, which have Ericsson's products used in their telecommunication networks. Ericsson provides product installation and maintenance support and guidance, but despite this, the product may have security related issues, either due to lack of following the instructions, human error or defect in the product itself or in a third party products attached. Ericsson’s Operation and Maintenance Security Service for OSS-RC networks aims to provide tools for checking the security level of the O&M product so that it meets all requirements and Ericsson’s own security related rules. Each customer has a unique telecommunications network structure and services, and so the security service has to be to create individually depending on the customer. The purpose of this thesis is to define the basic instructions for creating the security service for different customers.

Future vision of information networks according to EU 7th framework

The purpose of this thesis is to investigate projects funded in European 7th framework Information and Communication Technology- work programme. The research has been limited to issue ”Pervasive and trusted network and service infrastructure” and the aim is to find out which are the most important topics into which research will concentrate in the future. The thesis will provide important information for the Department of Information Technology in Lappeenranta University of Technology. First in this thesis will be investigated what are the requirements for the projects which were funded in “Pervasive and trusted network and service infrastructure” – programme 2007. Second the projects funded according to “Pervasive and trusted network and service infrastructure”-programme will be listed in to tables and the most important keywords will be gathered. Finally according to the keyword appearances the vision of the most important future topics will be defined. According to keyword-analysis the wireless networks are in important role in the future and core networks will be implemented with fiber technology to ensure fast data transfer. Software development favors Service Oriented Architecture (SOA) and open source solutions. The interoperability and ensuring the privacy are in key role in the future. 3D in all forms and content delivery are important topics as well. When all the projects were compared, the most important issue was discovered to be SOA which leads the way to cloud computing.

Genetic regulatory networks in avian B cells

Biology is turning into an information science. The science of systems biology seeks to understand the genetic networks that govern organism development and functions. In this study the chicken was used as a model organism in the study of B cell regulatory factors. These studies open new avenues for plasma cell research by connecting the down regulation of the B cell gene expression program directly to the initiation of plasma cell differentiation. The unique advantages of the DT40 avian B cell model system, specifically its high homologous recombination rate, were utilized to study gene regulation in Pax5 knock out cell lines and to gain new insights into the B cell to plasma cell transitions that underlie the secretion of antibodies as part of the adaptive immune response. The Pax5 transcription factor is central to the commitment, development and maintenance of the B cell phenotype. Mice lacking the Pax5 gene have an arrest in development at the pro-B lymphocyte stage while DT40 cells have been derived from cells at a more mature stage of development. The DT40 Pax5-/- cells exhibited gene expression similarities with primary chicken plasma cells. The expression of the plasma cell transcription factors Blimp-1 and XBP-1 were significantly upregulated while the expression of the germinal centre factor BCL6 was diminished in Pax5-/- cells, and this alteration was normalized by Pax5 re-introduction. The Pax5-deficient cells further manifested substantially elevated secretion of IgM into the supernatant, another characteristic of plasma cells. These results for the first time indicated that the downregulation of the Pax5 gene in B cells promotes plasma cell differentiation. Cross-species meta-analysis of chicken and mouse Pax5 gene knockout studies uncovers genes and pathways whose regulatory relationship to Pax5 has remained unchanged for over 300 million years. Restriction of the hematopoietic stem cell fate to produce T, B and NK cell lineages is dependent on the Ikaros and its molecular partners, the closely related Helios and Aiolos. Ikaros family members are zinc finger proteins which act as transcriptional repressors while helping to activate lymphoid genes. Helios in mice is expressed from the hematopoietic stem cell level onwards, although later in development its expression seems to predominate in the T cell lineage. This study establishes the emergence and sequence of the chicken Ikaros family members. Helios expression in the bursa of Fabricius, germinal centres and B cell lines suggested a role for Helios in the avian B-cell lineage, too. Phylogenetic studies of the Ikaros family connect the expansion of the Ikaros family, and thus possibly the emergence of the adaptive immune system, with the second round of genome duplications originally proposed by Ohno. Paralogs that have arisen as a result of genome-wide duplications are sometimes termed ohnologs – Ikaros family proteins appear to fit that definition. This study highlighted the opportunities afforded by the genome sequencing efforts and somatic cell reverse genetics approaches using the DT40 cell line. The DT40 cell line and the avian model system promise to remain a fruitful model for mechanistic insight in the post-genomic era as well.

Viral and cellular modulation of virus-induced apoptosis in experimental infection models

The aim of this study was to investigate herpes simplex virus type 1 (HSV-1)- and measles virus (MV)-induced cell death. HSV-1 with deletion in genes encoding infected cell protein (ICP)4 and protein kinase Us3 (d120) induced apoptosis and cathepsin activation in epithelial (HEp-2) and monocytic (U937) cells. Inhibition of cathepsin activity decreased the amount of d120-induced apoptosis indicating that d120-induced apoptosis could be cathepsin-mediated. Also, HSV-1 infection increased caspase activation suggesting that d120-induced apoptosis is probably caspase-mediated. Cystatin treatment decreased the activity of cathepsins and the replication of HSV-1 indicating that cathepsins contribute to HSV-1 infection. Interestingly, d120 induced also necroptosis in monocytic cells. This is the first report on necroptosis in HSV-1- infected cells. MV induced apoptosis in uninfected bystander T lymphocytes, probably via interaction of MV-infected monocytes with uninfected lymphocytes. The expression of death receptor Fas was clearly increased on the surface of lymphocytes. The number of apoptotic cells and the activation of cathepsins and caspases were increased in MVinfected U937 cells suggesting that MV-induced apoptosis could be cathepsin- and caspase-mediated. Cystatin treatment inhibited cathepsin activities but not MV-induced apoptosis. Besides HSV-1-induced apoptosis, innate immune responses were studied in HSV-1-infection. HSV-1 viruses with either ICP4 and Us3, or Us3 deletion only, increased the expression of Toll-like receptor (TLR)3 and stimulated its downstream pathways leading to increased expression of type I interferon gene and to functional interferons. These findings suggest that besides controlling apoptosis, HSV-1 ICP4 and Us3 genes are involved in the control of TLR3 response in infected cell.

Understanding change processes in business networks : a study of convergence in Finnish telecommunications 1985-2005

Aktörer inom telekommunikationsbranschen i Finland har genomgått en intensiv förändring under de senaste 25 åren, från 1980-talets självständiga företag till företag beroende av varandra, och även av aktörer inom närliggande branscher. I dag skapas telekommunikationsmarknaden inte endast av operatörerna, utan också av mediebolag (t.ex. MTV Media) och IT-företag (t.ex. TietoEnator). Gränserna mellan olika industrier håller därmed på att suddas ut - ett fenomen som allmänt benämns som teknologisk konvergens. Konvergens innebär att någonting integreras; det kan handla om t.ex. teknologier (telefoni och Internet), företag (AOL och Time Warner), industrier (telekom, media och IT-branscherna), tjänster (mobilt TV), produkter (PDA) osv. Detta innebär att ytterst få telekomaktörer ensamma kan vidareutveckla marknaden och tekniska lösningar. Samarbete mellan aktörer krävs; mobiltelefontillverkare, innehållsproducenter, operatörer osv. bör intesifiera sitt samarbete för att kunna erbjuda attraktiva tjänster och produkter till kunder och slutanvändare. Avhandlingen fokuserar speciellt på affärsnätverk och samarbetsmönster mellan nätverksaktörer som medel för att få tillgång till resurser som krävs i en konvergenskarakteriserad affärsomgivning. Avhandlingen lyfter fram vad den teknologiska konvergensen har inneburit för telekomaktörer, dvs. att företag tvingats förändra sina strategier och verksamhetsmodeller. För många företag i branschen har anpassningen till konvergenstänkande varit utmanande, och i vissa fall kan man till och med tala om att företagen upplevt en identitetskris. Den utförda forskningen visar att konvergens uppfattas på marknaden som en pågående förändringsprocess, där varje telekomaktör är tvungen att utvärdera sin roll och position i relation till andra aktörer inom branschen. Konvergensprocesser forsätter i framtiden med ökad intensitet. Aktörerna skapar medvetet sin omgivning genom att agera i olika roller, som kan sträcka sig över industrigränser. Avhandlingen påvisar även att externa händelser och industrikontexten påverkar dynamiken i ett affärsnätverk.