
Krešimir FertaljUniversity of Zagreb Faculty of Electrical Engineering and Computing
Krešimir Fertalj
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Introduction
Publications
Publications (81)
Recognition of domain names generated by domain generation algorithms (DGAs) is the essential part of malware detection by inspection of network traffic. Besides basic heuristics (HE) and limited detection based on blacklists, the most promising course seems to be machine learning (ML). There is a lack of studies that extensively compare different...
Modern organizations need to understand and constantly improve their business processes (BPs) in order to make successful business decisions. This paper describes an integration model for building a Business Process Management Application (BPMA) and connecting the BPMA with legacy systems based on Service-Oriented Architecture (SOA). A BPMA is an a...
This paper presents a review of current denial of service (DoS) attack and defence concepts, from a theoretical ad practical point of view. Seriousness of DoS attacks is tangible and they present one of the most significant threats to assurance of dependable and secure information systems, which is growing in importance. Rapid development of new an...
In past, detection of network attacks has been almost solely done by human operators. They anticipated network anomalies in front of consoles, where based on their expert knowledge applied necessary security measures. With the exponential growth of network bandwidth, this task slowly demanded substantial improvements in both speed and accuracy. One...
Quality assurance in higher education implies different student surveys that examine teaching, learning environments and educational outcomes. It is crucial to convince students that survey is fully anonymous because it is an essential prerequisite for getting the right answers from students about teaching process.The application of information tec...
Positioning technology is lately widely used in many scientific fields to collect movement and biodiversity data for further analysis. That generates enormous amount of positions and tracking data and impose the need for developing new algorithms for analysis and prediction, which are managed in ever growing partial and incomplete software solution...
Understanding and keeping track of business processes is one of the most important tasks in development of business software. However, any documentation other than source code cannot be completely reliable. On the other hand, source code is rather unreadable by non-developers and can be challenging to determine business processes distributed among...
Denial of service (DoS) attacks present one of the most significant threats to assurance of dependable and secure information systems. Rapid development of new and increasingly sophisticated attacks requires resourcefulness in designing and implementing reliable defences. This paper presents an overview of current DoS attack and defence concepts, f...
Enterprise resource planning (ERP) systems are the most important software for many types of businesses. Software defects inserted on working ERP system can cause significant cost to their users. Existing software reliability models usually don't consider any financial impact at all. A model proposed in this paper links the ERP application layer wi...
This paper is focused on understanding techniques used to formally verify behaviour of business processes developed using WS-BPEL standard. The first part of the paper gives an overview of WS-BPEL control-flow constructs. We analyze offered constructs and try to derive control-flow scenarios that can be built out of them. Derived complex control-fl...
Collars equipped with GPS/GSM device provide automated remote tracking of animal at successive time intervals. Since animal movement is complex and irregular, methods based on repetitiveness of human movement cannot be applied to animals. In this paper we propose a method for animal movement pattern discovery using Hidden Markov model. We present a...
In today's society, where access to the technology is becoming a basic human need, the need for software applications and developers is rapidly increasing while the labor market does not meet the needs of entrepreneurs. Workload of software companies is constantly increasing, as they not only have to develop new applications, but must also maintain...
Aspect-oriented programming has been introduced in order to increase the modularity of object-oriented programs and is claimed to improve software quality. Although there are various researches on this claim, the question to what extent aspect-oriented programming improves the quality of programs depending on a developer's experience still remains....
When developing systems based on web service compositions, it is important to define a methodology for handling web service interfaces. Handling web service interfaces comprises publishing, storing and retrieving of interfaces. UDDI is a well-known standard that offers aforementioned possibilities. This paper defines methodology with necessary step...
Involving students into real-world projects and real teamwork environment is of the great importance in software engineering education that is sometimes ignored in academic environments. The Bologna Process reforms gave the authors an opportunity for necessary changes in the teaching methodology. Although the real-world projects have generated the...
This paper presents the possibilities of using Weibull statistical distribution in modeling the distribution of defects in ERP systems. There follows a case study, which examines helpdesk records of defects that were reported as the result of one ERP subsystem upgrade. The result of the applied modeling is in modeling the reliability of the ERP sys...
Resource Constrained Project Scheduling Problems (RCPSP), especially their stochastic variants, and the methods operating on them represent a general project scheduling optimization framework. This paper presents the survey of methods and models that are put into the historical context and are categorized according to their working principles. It a...
Requirements analysis phase of information system development is still predominantly human activity. Software requirements are commonly written in natural language, at least during the early stages of the development process. In this paper we present a simple method for automated analysis of requirements specifications for data-driven applications....
Integrating prerequisite relationships, partially defined as graph components, produces a directed graph that corresponds to a well-defined and well-behaved workflow consisting only of and-splits and and-joins. Such a workflow often cannot be transformed to a structured workflow. This paper presents an approach to producing a corresponding structur...
Virtual teams are increasingly engaged in globalized business environments. Virtual teams work across space, time and organizational boundaries with links ensured by information and communication technologies. Communication, collaboration, and knowledge exchange are the most important in virtual teams' operations and their efficiency directly influ...
Virtual teams are being increasingly used to run projects in globalized business environments. Virtual teams primarily rely on information and communication technologies to support many of communicative and collaborative activities that traditional collocated teams take for granted. To be efficient, virtual teams need more than just a plain set of...
Adoption of Web services delivered interoperability among different platforms. Nevertheless, a real contribution of service oriented systems is not only operability but powerful ways of inter and intra-corporative integration of autonomous IT systems. The most popular term, mentioned in this context, is - orchestration. Orchestration is a strongly...
Constant upgrading of Enterprise Resource Planning (ERP) systems is necessary, but can cause new defects. This paper attempts to model the likelihood of defects after completed upgrades with Weibull defect probability density function (PDF). A case study is presented analyzing data of recorded defects obtained for one ERP subsystem. The trends are...
Enterprise Resource Planning (ERP) system is a complex software system that supports network of different business processes. Sales of such systems has expanded in the late 90s. In that period ERP installations dominated in large business organizations, but today are commonplace in small and medium-sized enterprises. It's very important for ERP buy...
GPS technology enables collection of moving object's positions remotely. Recent research on moving objects concerns analysis of their movement to increase the knowledge about their movement patterns. Discovery of biogeographically significant locations such as a den, rendezvous sites or kill-sites is very important in order to gain insight into ani...
The number of application domains in which systems must deliver continuous reliable service during update is growing as well as the application of aspect-oriented paradigm in such systems. In this paper we address the problem of updating running aspect-oriented software. The goal of the research is to design and to build the model for dynamic updat...
This paper introduces main concerns when it comes to composite Web service development. Firstly, it introduces a concept of service granularity. One of the most frequent questions, most enterprise architects often address, is how big a service should be. Granularity is a measure addressing this question. It can be defined as the overall quantity of...
Assigning responsibilities to classes is arguably the most important step when creating object-oriented software design. This step depends greatly on human judgment. Our objective is to automate this process using metaheuristic optimization algorithms. Four different algorithms (simple genetic algorithm, hill climbing, simulated annealing, and part...
Whereas research on moving objects is involved in a variety of different application areas, models and methods for movement prediction are often tailored to the specific type of moving objects. However, in most cases, prediction models are taking only historical location in consideration, while characteristics specific to certain type of moving obj...
This paper focuses on ontology and taxonomy of services. Service is a paradigm frequently mentioned with the genesis of idea about Service Oriented Architectures - SOA. SOA is still discussed even though the idea about information system made of services is not new. In the last couple of years, SOA has become attractive, perspective and promising e...
Rule based systems (RBS) have been recognized as probably the best solution for knowledge based expert systems. This article tries to provide the overview of the architecture and basic characteristics of the RBS, focusing on both their weaknesses and strengths. Based on a theory, rule based expert system for web shop error detection has been propos...
Introduction of a complex ERP system like SAP into a heterogeneous academic environment like the University of Zagreb is far from being a trivial task. The University comprises more than 30 constituents, called faculties or academies, geographically dispersed, with long and specific traditions. Financing according to the lump sum principle, enforce...
The systems aimed for manipulating large number of courses and students are called Learning Management Systems (LMS). A LMS can have excellent performance implemented through advanced Web technologies but it is often accompanied by a poor or rarely used repository of institution's educational content. It has still remained. Still remains a problem...
The interpolated fast Fourier transform (IFFT) was one of the first methods for the highly accurate estimation of sine wave parameters, and its first successful descendant was analytical leakage compensation [which is commonly called analytical solution (AS)]. The AS estimate of frequency is a whole class of solutions whose variance depends on a fr...
The development of enterprise IT architectures has become a real challenge in the recent years. Most of the issues stem from heterogeneous applications, platforms and environments that need to operate as a homogeneous unit. It is for this reason that the enterprise IT systems of today are increasingly driven to integrate all of their current and fu...
Systems manipulating large number of courses and students are called learning management systems (LMS). LMS have excellent performances implemented through advanced Web technologies but often poor or rarely used repository for storing institution's educational data. There still remains a problem of how to allow users of LMS to easily modify and int...
Due to the advances in Global Positioning System (GPS) and wireless technology, which enabled collection of large amount of data about moving objects, research on moving objects experiences its expanded phase. In this paper we focus on short-term prediction of moving object's movement using Markov chain adapted to spatiotemporal data. We demonstrat...
Enterprise Resource Planning (ERP) represents a general business application software solution which is applicable in different business operations. Therefore, it covers areas which are common to a certain group of business operations (e.g. manufacturing, services, financial services, public services, etc.). However, business operations , no matter...
Refactoring is a technique that is concerned with changing internal software design while external software behaviour is preserved. Although the refactoring process seems to be clear and well defined, there are difficulties with regard to its automation. Various refactoring tools have been developed so far, which makes not easy for a developer to c...
This paper presents concepts of virtualization techniques. Both server virtualization and desktop virtualization are briefly presented, but desktop virtualization is discussed in more details. As the size of computer systems grows every day with new applications, and with new client and market requirements, it is obvious that something must be done...
Along the integration of business systems with IT infrastructure, new ideas come up oriented towards their better adapting to each other. Business systems become extremely complex, resulting in necessity to develop new architectures that will accommodate all needs for different and volatile business requirements. Service oriented architectures repr...
This paper presents a proprietary application generator based on UML specification. The tool is designed for generating the source code in various programming languages from the same specification. The main characteristics of the existent tools are explained in brief. Main generator capabilities and merits are presented as well as an example of usa...
This paper presents a application generator based on UML specification. The tool is capable of generating the source code in various programming languages from the same specification. The main characteristics of the existent tools are explained in brief. Main generator capabilities and merits are presented as well as an example of usage based on a...
The large companies business processes, especially in production, depend on IT (Information Technology) infrastructure, including one or more of various computing environments as NW (Network), DB (Database) and SW (software) modules needed for the implementation, management and monitoring of the business activities. The worldwide implementation of...
An automated machine cuts the rolls of corrugated paper longitudinally and splits the paper stripe into multiple conveyors, where in each of them a different equidistant lateral cut can be applied. There is a choice of input rolls of infinite length but different widths. The market requirement for large series of different rectangle-shaped articles...
One of the most accurate and commonly accepted methods for spectral analysis, i.e., estimation of frequency from samples of a signal, is analytical leakage compensation, briefly called analytical solution (AS). The AS estimate is negligibly biased, but it is the whole class of solutions whose variance depends on a free parameter named K. Thus, an i...
This paper describes some of the most common problems that can occur while writing an engine for flow control in workflow management software. The emphasis is put on implementing workflow control patterns, particularly on splits and matching synchronization points, and on milestones and mutual exclusions. After brief introduction and description of...
This article describes various advantages and disadvantages of SMS, WAP, J2ME and Windows CE technologies in designing mobile applications. In defining the architecture of any software application it is important to get the best trade-off between platform's possibilities and design requirements. Achieving optimum software design is even more import...
This paper elaborates the present stage predictable direction of future development of Sine Wave Calculator (SWC), a simple method for signal analysis in time domain that provides accuracy comparable to the best classical methods (relative errors about few times 10-6). The main SWC advantages are extreme simplicity, possibility of selection of samp...
This paper elaborates the present stage and predictable direction of future development of Sine Wave Calculator (SWC), a simple method for signal analysis in time domain that provides accuracy comparable to the best classical methods (relative errors about few times 10-6). The main SWC advantages are extreme simplicity and straightforward calculati...
The development of Extreme Programming (XP) in nineties initiated lively discussion in software development community between those promoting XP and those advocating its "older big brother" Rational Unified Process (RUP). They are both well-established and proven in practice, but nowadays it is clear that they cannot respond to all the new challeng...
Modern software development business, as a very dynamic and often risky process, imposes new approaches to planning and organisation of the work. At present, a typical team can apply one of the agile methodologies, among which RUP and XP are the most common. They are both well-established and proven in practice, but nowadays it is clear that they c...
Knowledge in today's business has imposed itself as one of key factors that are defining success. As a result of that many companies, especially global ones, introduce knowledge management into their business processes to achieve optimal exploitation of knowledge. First part of this article addresses theory of knowledge management. That part descri...
The two widely used approaches to data modelling, the application of Unified Modelling Language (UML) and Object Role Modelling (ORM) are compared. Since one of the purposes of modelling is to present and clarify the system design, the key comparison criteria were expressivity, i.e., clear presentation and easy perception of the stored information...
Knowledge in today's business has imposed itself as one of key factors that are defining success. As a result of that many companies, especially global ones, introduce knowledge management into their business processes to achieve optimal exploitation of knowledge. First part of this article addresses theory of knowledge management. That part descri...
This paper describes the architecture of a system called Business Information System Feasibility. The purpose of the system is to establish a base for an impartial and computer-aided decision-making tool for choice of information system software and/or its provider, for evaluation of computerization projects and for validation of existing informati...
This paper presents the results of an investigation performed in 2001 under the title Comparative Analysis of Information Systems Software in Croatia. The focus was set on the comparative analysis of domestic and foreign Enterprise Resource Planning (ERP) software, which is present in Croatia. The investigation was performed from the standpoint of...
This paper presents a proprietary application generator that generates the source code based on code templates and on user-defined parameters applied to these templates. The generator is designed to generate source code written in different languages and for different types of applications. The underlying data model and structure of the templates a...
The paper describes possible enhancements of peer-to-peer (P2P) file transfer by providing users with a remote control system in order to initiate the start of file transfer on their machine(s). In addition, control and monitoring of the file transfer can be performed on their machine(s) even if users are logged off and regardless of possible techn...
This paper summarizes our efforts in implementing a working multi-level secure database prototype. We have chosen Belief-Consistent Multilevel Secure Relational Data Model (BCMLS) as a basis for our prototype because of its comprehensive semantics for interpreting all stored information. While semantically superior to other models, this model has n...
We describe the use of code generators in Web development process. An overview of key features of Web applications and Web application development is given. The research focused on how those features are implemented and supported by different Web application generators and other Web development tools. The quality and maintainability of generated co...
We summarize our efforts in implementing a working multilevel secure database prototype. We have chosen belief-consistent multilevel secure relational data model (BCMLS) as a basis for our prototype because of its comprehensive semantics for interpreting all stored information. While semantically superior to other models, this model has not been im...
This paper initially presents possible application of standard e-connnerce models in banking industry. Required resources and standard e-connnerce models are briefly considered and followed by the examples of implementation of particular models. There follows a description of application of some of the general models regarding the banking business....
We describe the architecture of a system called wMail, intended for e-mail messaging using wireless application protocol (WAP) enabled cell phone. The software integrates all of user's Internet mailboxes with the user's cell phone, turning them into instant messaging systems available at any time from anywhere. On the basis of a chosen time period...
What is important when choosing the multilevel security model? Is it merely the way that model implements integrity rules (i.e. entity integrity property, referential integrity property) or should the model's semantics of what user on some specific level can see and/or believe be considered as well? In this paper, the basic concepts of multilevel s...
Proactive system monitoring is the search for potential problems in the Information Systems (IS) before they occur. With reference to IS, monitoring is always proactive. Watching for evidence of emerging or potential problems and identifying their source (factor), checking available disk space, the health of essential processes, probing systems to...
An application generator has resulted from the authors' efforts to improve the development of interactive database applications. The developed tool is based on a meta-base. The meta-base comprises an extended data model, the programming language description and some additional information to support the generation process. The procedures described...
In Croatia the Ministry of Science and Technology is the major provider of funds for higher education. There are four universities, each consisting of a number of relatively independent and dislocated faculties and academies. In 1997, the Ministry engaged the authors to computerize the system for subsidized nourishment of the university students. T...
CROFlora is a multi-user database application for species-oriented and specimen-oriented systematic and taxonomic work on Croatian flora. It is designed for dealing with all kinds of data that are commonly used in systematic botany and floristic work. CROFlora comprises several main modules: (1) taxonomy, (2) herbarium, (3) literature, (4) chorolog...
Some issues related to the transformation of a traditional IS service department into a modern team-based information center are discussed. The process of transformation comprises human resources analysis, investigation of possible ways of transformation, proposal of a new organization and constitution of development teams (DTs). New organization i...
This paper describes the architecture and development of a web-based system for producing, gathering and exchange of multimedia advertisements. The advertisements are classified and stored into a database on the server. The information about an advertisement includes free text and a set of values for predefined attributes. Optionally, any other com...
This paper describes the architecture and development of a Web-based system for producing, gathering and exchanging multimedia advertisements. The advertisements are classified and stored in a database on the server. The information about an advertisement includes free text and a set of values for predefined attributes. Optionally, any other comput...
A client-server database application, named CROFlora has been developed to foster the endeavour for the systematic and taxonomic classification of the Croatian flora. The software consists of several modules to encompass the taxonomy, herbarium, literature, horology and ecology. The paper presents the underlying database structure, querying and rep...
In the growing discipline of Project Management (PM), the techniques used for project planning mainly include methods developed at dawn of modern PM back in 1950's. Therefore, they are influenced by Operational Research and are founded on Program Evaluation and Review Technique (PERT) or on Critical Path Method (CPM).To fulfil the growing requests...