Ivan Voras

Explore the startup landscape of East European countries and review the differences in the concepts of limited liability companies and company equity in approaching the market. This quick reference guide is structured around the primary author, Ivan Voras, with additional chapters written by guest collaborators. Chapters are concise and focus on ways to overcome the various obstacles start-ups may face. You'll benefit from regionally relevant advice on finding problems worth solving as a… Show more

Explore the startup landscape of East European countries and review the differences in the concepts of limited liability companies and company equity in approaching the market. This quick reference guide is structured around the primary author, Ivan Voras, with additional chapters written by guest collaborators. Chapters are concise and focus on ways to overcome the various obstacles start-ups may face. You'll benefit from regionally relevant advice on finding problems worth solving as a startup, how to hire people, how to raise investment rounds, and how to find and communicate with investors. Show less

Slides of my blockchain workshop for developers

This is not a technical text. This book is for everyone who has looked in terror as the price of Bitcoin (& other digital currencies) continually rises and was tempted to buy in even though s/he doesn't understand it or doesn't know what's going on in the background. It describes what makes Bitcoin and other cryptocurrencies tick, what are their current and future possibilities, and how can they be used, in plain language.

Cloud computing promises efficient use of hardware resources through virtualization and elastic computing facilities. Various cloud computing solutions have emerged on the market from open- source communities and commercial vendors. In this paper we discuss criteria for feature comparison of private cloud platforms and compare several open-source and commercial products. We test performance of hypervisors used in these clouds with a set of benchmark suites containing tests for various aspects… Show more

Cloud computing promises efficient use of hardware resources through virtualization and elastic computing facilities. Various cloud computing solutions have emerged on the market from open- source communities and commercial vendors. In this paper we discuss criteria for feature comparison of private cloud platforms and compare several open-source and commercial products. We test performance of hypervisors used in these clouds with a set of benchmark suites containing tests for various aspects of the system. We discuss the results in the context of what is commonly described as a scientific workload. The described feature and performance differences can help make wiser platform choices. Show less

The phenomenon of social networking has entered the lives of millions of people via the ubiquitous Web-based platforms such as Facebook and Google+ which are centralized platforms completely controlled by single entities. However, a complete parallel message-passing infrastructure already exists and has the benefit of 30 years experience and investments: the SMTP e-mail network, which together with the latest technologies can be utilized to provide a completely decentralized, convenient… Show more

The phenomenon of social networking has entered the lives of millions of people via the ubiquitous Web-based platforms such as Facebook and Google+ which are centralized platforms completely controlled by single entities. However, a complete parallel message-passing infrastructure already exists and has the benefit of 30 years experience and investments: the SMTP e-mail network, which together with the latest technologies can be utilized to provide a completely decentralized, convenient, private and even fault-tolerant social networking platform. This work in progress aims to design and implement a proof of concept of such idea. Show less

Cloud computing promises on- demand scalability and flexibility for the enterprise environment and open source products have a large presence in this area. We have devised an elaborate set of criteria for evaluation and comparison of open source IaaS cloud computing solutions which can be used for ranking and choosing between the available products. We explain each criteria group, and give both the rationale and the estimated impact of the criteria. We also briefly introduce a number of most… Show more

Cloud computing promises on- demand scalability and flexibility for the enterprise environment and open source products have a large presence in this area. We have devised an elaborate set of criteria for evaluation and comparison of open source IaaS cloud computing solutions which can be used for ranking and choosing between the available products. We explain each criteria group, and give both the rationale and the estimated impact of the criteria. We also briefly introduce a number of most common open source cloud computing IaaS solutions to be evaluated using the explained criteria. Show less

Cloud computing is becoming a mainstream technology in enterprise environment, promising more efficient use of hardware resources through virtualization, elastic computing facilities and secure management of user applications. Various cloud computing architectures are emerging and several commercial and open source products on the market advertise a rich feature-set. While commercial vendors try to give potential users the (not necessarily unbiased) tools to reason on the comparative advantages… Show more

Cloud computing is becoming a mainstream technology in enterprise environment, promising more efficient use of hardware resources through virtualization, elastic computing facilities and secure management of user applications. Various cloud computing architectures are emerging and several commercial and open source products on the market advertise a rich feature-set. While commercial vendors try to give potential users the (not necessarily unbiased) tools to reason on the comparative advantages of their product, the open source community trusts users to make a well-informed selection on their own. In this paper we take a look at the open source cloud solutions and discuss the criteria that can be used to evaluate the stability, performance and features of open source clouds, and compare some available solutions. The evaluation criteria focus on three main components of a cloud solution – the storage layer, the virtualization layer, and the management layer. In addition, we explain the motivation for application of open source cloud solutions from an enterprise perspective, and discuss the potential benefits of these solutions for private cloud computing environments. Show less

Many classical algorithms like the Bloom filter were envisioned and created at a time when computers were the size of rooms and multithreading was not yet even explored theoretically. The landscape of modern mainstream computer systems today is heavily dominated with multi-core CPU-s but the effort to make full use of such systems is still ongoing. The Bloom filter has proven itself useful both as a core algorithm and as a supportive or optimizing addition to other data classification… Show more

Many classical algorithms like the Bloom filter were envisioned and created at a time when computers were the size of rooms and multithreading was not yet even explored theoretically. The landscape of modern mainstream computer systems today is heavily dominated with multi-core CPU-s but the effort to make full use of such systems is still ongoing. The Bloom filter has proven itself useful both as a core algorithm and as a supportive or optimizing addition to other data classification algorithms. This work explores adaptations to the basic Bloom filter algorithm for use in multithreaded applications on contemporary SMP systems and the consequences of such adaptations to its overall efficiency. Show less

In a technological landscape that is quickly moving toward dense multi-CPU and multi-core computer systems, where using multithreading is an increasingly popular application design decision, it is important to choose a proper model for distributing tasks across multiple threads that will result in the beset efficiency for the application and the system as a whole. The work described in this paper creates, implements and evaluates various models of distributing tasks to CPU threads and… Show more

In a technological landscape that is quickly moving toward dense multi-CPU and multi-core computer systems, where using multithreading is an increasingly popular application design decision, it is important to choose a proper model for distributing tasks across multiple threads that will result in the beset efficiency for the application and the system as a whole. The work described in this paper creates, implements and evaluates various models of distributing tasks to CPU threads and investigates their characteristics for use in modern high-performance network servers. Thresults presented here comprise a roadmap of models for building multithreaded server applications for modern server hardware and Unix-like operating systems. Show less

This paper presents the architecture and characteristics of a memory database intended to be used as a cache engine for web applications. Primary goals of this database are speed and efficiency while running on SMP systems with several CPU cores (four and more). A secondary goal is the support for simple metadata structures associated with cached data that can aid in efficient use of the cache. Due to these goals, some data structures and algorithms normally associated with this field of… Show more

This paper presents the architecture and characteristics of a memory database intended to be used as a cache engine for web applications. Primary goals of this database are speed and efficiency while running on SMP systems with several CPU cores (four and more). A secondary goal is the support for simple metadata structures associated with cached data that can aid in efficient use of the cache. Due to these goals, some data structures and algorithms normally associated with this field of computing needed to be adapted to the new environment. Show less

One of the most common basic techniques for improving the performance of web applications is caching frequently accessed data in fast data stores, colloquially known as cache daemons. In this paper we present a cache daemon suitable for storing complex data while maintaining fine-grained control over data storage, retrieval and expiry. Data manipulation in this cache daemon is performed via standard SQL statements so we call it SQLcached. It is a practical, usable solution already implemented… Show more

One of the most common basic techniques for improving the performance of web applications is caching frequently accessed data in fast data stores, colloquially known as cache daemons. In this paper we present a cache daemon suitable for storing complex data while maintaining fine-grained control over data storage, retrieval and expiry. Data manipulation in this cache daemon is performed via standard SQL statements so we call it SQLcached. It is a practical, usable solution already implemented in several large web sites. Show less

When considering the usability of computer applications one, of the most important factors is the interface they provide for data manipulation. Historically, though each application has defined it's own user interface, some types of interfaces have emerged as most applicable for certain types of data. Over time, some applications (or types of applications) have gained enough popularity that they became ubiquitous and well-known to most computer users to the extent that users consider them the… Show more

When considering the usability of computer applications one, of the most important factors is the interface they provide for data manipulation. Historically, though each application has defined it's own user interface, some types of interfaces have emerged as most applicable for certain types of data. Over time, some applications (or types of applications) have gained enough popularity that they became ubiquitous and well-known to most computer users to the extent that users consider them the norm, and as such, optimal for their daily tasks. In this paper we present an idea and implemented method of exposing data from a web content management system in the form of hierarchical file system, manageable and editable by usual file management and office application tools. Show less

For some, E-Campus is still a futuristic idea. For some, it’s the name of a new project. But for Faculty of Electrical Engineering and Computing, largest technical faculty in the fields of electrical engineering and computing in Croatia, it’s a daily routine and just another way of communication with students. Common misbelief is that E-Campus is all about choosing the right Learning management system, selecting the appropriate Student information system or Content management system. Of course… Show more

For some, E-Campus is still a futuristic idea. For some, it’s the name of a new project. But for Faculty of Electrical Engineering and Computing, largest technical faculty in the fields of electrical engineering and computing in Croatia, it’s a daily routine and just another way of communication with students. Common misbelief is that E-Campus is all about choosing the right Learning management system, selecting the appropriate Student information system or Content management system. Of course these are very important, but the most important thing is to connect all these pieces together. Even when selecting the best software it’s necessary to check if it satisfies all the needs of our users. Question that everyone should ask is: Have the developers of selected software predicted all needs for the E-Campus that I want to have? That I want to be a part of? Show less