Ivan Milenković

Belowground infections of the invasive Phytophthora plurivora pathogen enhance the suitability of red oak leaves to the generalist herbivore Lymantria dispar

1. Globally, vast areas of forest are currently threatened by Lymantria dispar L. and Phytophthora species, which cause widespread declines and cascading ecological impacts. One important aim of evolutionary and ecological studies is to understand their interactions.

Identity Management — A Survey

The rise of network-based, automated services has brought some fundamental changes to every organization’s activities. One of the most important changes that have occurred is the change in the way the business companies offered their products to customers. The business processes have become increasingly automated. As a result, the way in which customers create trust relationships with service providers has changed, because business transactions are conducted online. Traditional ways of establishing trust relationships between negotiating parties are no longer applicable. Windley (2005) points out that the usual trust marks that customers have relied on in the past are either missing or are easily forged. Moreover, in addition to changes in the relationship between business companies and their customers, the whole business process has become automated. The relationships with partners, suppliers, and employees have moved to the electronic world. This leads to increased risk of attacks such as identity theft and identity disclosure. Merchant web applications must be properly protected in an e-commerce environment (Stankovic et al., 2012). Therefore, digital identity management needs to be properly implemented in order to elevate the overall security of the business process.

Using Kerberos protocol for Single Sign-On in Identity Management Systems

Abstract: Today, identity management systems are widely used in different types of organizations, from academic and government institutions to large enterprises. An important feature of identity management systems is the Single Sign-On functionality. Single Sign-On allows users to authenticate once, and freely use all services and resources available to them afterwards. In this paper, we present the usage of Kerberos in identity management systems. An overview of Kerberos protocol, state of the art of identity management systems and different generic architectures for identity management is given in the paper. Also, we present a Single Sign-On identity management architecture proposal based on Kerberos protocol, and discuss its properties. Special attention was given to authentication, authorization and auditing.

Gamified educational website conversion optimization

In this paper, we proposed novel approach to e-learning website conversion optimization using gamification. Analysis of current website analytics has identified several gaps between expected and present state. We used traditional three-stage conversion optimization process to first set up new conversion goals, next to track realization, and further to perform optimization using gamified landing pages. Our expectations are focused on content download and student engagement optimization. Though our research focus was on education, findings from this paper may be applicable to other fields.

A multimodal biometrics system implemented using open source technology

Because of the rising need for reliable biometric systems, finding different ways for improving biometric system performance becomes a significant problem. A solution to this problem is the integration of more different biometric modalities, known as multimodal biometrics. In this paper a description of a real multimodal biometrics system, developed on Faculty of organisational sciences using open source technology is given. Unimodal biometric solutions are presented, system performance measurements for different information fusion methods given and multimodal biometric database used for testing system performance is described.

Using open source software for web application security testing

Web applications are a standard part of our everyday lives. Their purpose can vary significantly, from e-banking to social networks. However, one thing is similar - users have generally high expectations from different web applications. To assure such high expectations, proper web application testing is necessary. Non-functional testing is an important part of web application testing. As technology advances and requirements become more complex, the importance of non-functional application aspects becomes even greater. It is necessary to identify non-functional requirements of web applications which are important to users, implement those requirements and test them.

Optimization of thresholds in serial multimodal biometric systems

Multimodal biometric verification systems use information from several biometric modalities to verify an identity of a person. The false acceptance rate (FAR) and false rejection rate (FRR) are metrics generally used to measure the performance of such systems. In this paper we propose a novel approach to determine the upper and lower acceptance thresholds in sequential multimodal biometric matching, in such a way that the expected values of FAR and FRR for the entire system are minimized. We linearize locally the score distributions of both genuine users and impostors using the least squares method, and derive formulas for the approximated FAR and FRR for each matcher. Further, we aim to minimize both probabilities for entire processing chain. In order to find the best compromise between them, we analyze the efficient solutions to the associated bi-objective programming problem. The results of our experiments are also reported in the paper. They showed a good performance of the sequential multiple biometric matching system based on optimized thresholds comparing with the widely adopted parallel fusion multimodal biometric systems.

Four different Phytophthora species that are ableto infect Scots pine seedlings in laboratory conditions

Abstract To investigate susceptibility of young Scots pine seedlings to four Phytophthora species: Phytophthora cactorum, Phytophthora cambivora, Phytophthora plurivora and Phytophthora pini; seven-day-old seedlings of Scots pine (15 seedlings per experiment) were infected using agar plugs of the respective species. Control group also consisted of 15 seedlings and was inoculated with sterile agar plugs. Results unambiguously show that after 4.5 days, all seedlings show clear signs of infection and display severe symptoms of tissue damage and necrosis. Moreover, three and two seedlings in the P. cactorum and P. cambivora infected seedlings groups, respectively, collapsed. The length of largest necrosis measured 13.4±3.90 mm and was caused by P. cactorum. To rule out any putative contamination or infection by secondary pathogens, re-isolations of pathogens from infection sites were performed and were positive in 100% of plated pieces of infected seedlings. All re-isolations were, however, negative in the case of the control group. Detailed microscopic analyses of infected tissues of young seedlings confirmed the presence of numerous Phytophthora species inside and on the surface of infected seedlings. Therefore, our results suggest Phytophthora spp. and mainly P. cactorum and P. cambivora as aggressive pathogens of Scots pine seedlings and highlight a putative involvement of these species in the damping off of young Scots pine seedlings frequently observed in forest nurseries.

Possibility of detecting species from the Phytophthora genus in the rhisosphere soil of oak trees using visual crown assessment

This paper explains biological background of the project. Oak decline in Polish stands in recent years has become a serious problem. Symptoms of disease like thinning crowns, yellowing of the leaves or the appearance of dark exudates on the trunks are observed. Such symptoms are characteristic for pathogenic organisms of the genus Phytophthora. Identification and confirmation of the presence of these pathogens is difficult. That is why we have tried to estimate the presence of pathogens in the rhizosphere soil in oak stands on the basis of visual assessment of crowns trees with symptoms typical of Phytophthora infection.

Using 3D Models for Improving Face Recognition

Face recognition algorithm Principal Component Analysis (PCA) has a significant performance drop when comparing photographs taken from different angle. In this paper a 3D model was used for improving that performance. Model enables us to transform the face image which is taken from certain angle to en face. Model has been tested against biometric database formed at the Faculty of Organizational Sciences. Image rotation based on the model was performed before matching with the en face images from the database. Study results show that algorithm precision on biometric verification and identification has been seriously improved.