Exploratory Analysis of Pairwise Interactions in Online Social Networks

In the last few decades sociologists were trying to explain human behaviour by analysing social networks, which requires access to data about interpersonal relationships. This represented a big obstacle in this research field until the emergence of online social networks (OSNs), which vastly facilitated the process of collecting such data. Nowadays, by crawling public profiles on OSNs, it is possible to build a social graph where "friends" on OSN become represented as connected nodes. OSN connection does not necessarily indicate a close real-life relationship, but using OSN interaction records may reveal real-life relationship intensities, a topic which inspired a number of recent researches. Still, published research currently lacks an extensive exploratory analysis of OSN interaction records, i.e. a comprehensive overview of users' interaction via different ways of OSN interaction. In this paper we provide such an overview by leveraging results of conducted extensive social experiment which managed to collect records for over 3,200 Facebook users interacting with over 1,400,000 of their friends. Our exploratory analysis focuses on extracting population distributions and correlation parameters for 13 interaction parameters, providing valuable insight in online social network interaction for future researches aimed at this field of study.Comment: Journal Article published 2 Oct 2017 in Automatika volume 58 issue 4 on pages 422 to 42

Intelligent data sources and integrated data repository as a foundation for business intelligence analysis

Abstract: Data mining and data analysis in general demonstrate high dependency on data quality. Gathering the right data of high enough quality takes most of researcher’s time and often demonstrates need for some additional data to be parsed. In order to eliminate or at least reduce required effort for this first phase of every analysis, authors of this paper present the idea of Integrated Data Repository and Intelligent Data Source. Concepts of those components are presented and approach to their development is suggested together with the high-level view of the system architecture. Finally, an experimental implementation is described

Poboljšanje rezultata hijerarhijskog grupiranja podataka primjerenijim tretiranjem tipova podataka i prilagodbom mjere udaljenosti

Hierarchical clustering method is used to assign observations into clusters further connected to form a hierarchical structure. Observations in the same cluster are close together according to the predetermined distance measure, while observations belonging to different clusters are afar. This paper presents an implementation of specific distance measure used to calculate distances between observations which are described by a mixture of variable types. Data mining tool ‘Orange’ was used for implementation, testing, data processing and result visualization. Finally, a comparison was made between results obtained by using already available widget and the output of newly programmed widget which employs new variable types and new distance measure. The comparison was made on different well-known datasets.Hijerarhijsko grupiranje se koristi za grupiranje objekata promatranja u grupe koje se dalje pripajaju te tako tvore hijerarhijsku strukturu. Prema odabranoj mjeri udaljenosti instance koje pripadaju istoj grupi su ’blizu’ dok su instance koje pripadaju različitim grupama ’udaljenije’. U ovom članku prikazana je implementacija specifične mjere udaljenosti koja se koristi za izračun udaljenosti izme.u instanci koje su opisane atributima različitih tipova podataka. Alat za dubinsku analizu podataka ’Orange’ je odabran za implementaciju, testiranje, obradu podataka te vizualizaciju rezultata. članak uz opis specifikacije novih varijabli te mjere udaljenosti tako.er daje usporedbu rezultata dobivenih otprije poznatim modulom i novim modulom koji koristi nove tipove podataka i novu mjeru udaljenosti. Usporedba je napravljena nad različitim poznatim skupovima podataka

Improved Visualization of Frequent Itemset Relationships Using the Minimal Spanning Tree Algorithm

Descriptive data mining techniques offer a way of extracting useful information out of large datasets and presenting it in an interpretable fashion to be used as a basis for future decisions. Since users interpret information most easily through visual means, techniques which produce concise, visually attractive results are usually preferred. We define a method, which converts transactional data into tree-like data structures, which depict important relationships between items contained in this data. The new approach we propose is offering a way to mitigate the loss of information present in previously developed algorithms, which use mined frequent itemsets and construct tree structures. We transfer the problem to the domain of graph theory and through minimal spanning tree construction achieve more informative visualizations. We highlight the new approach with comparison to previous ones by applying it on a real-life datasets – one connected to market basket data and the other from the educational domain

Reduced level of protein and free-choice feeding in Zagorje turkey nutrition

Zagorski puran postaje sve zanimljiviji u razvoju takozvane alternativne ili organske proizvodnje peradskog mesa u Hrvatskoj. Tehnologija uzgoja i hranidbe zagorskih purana još nije definirana i nastoji se iznaći što jednostavnija i jeftinija rješenja. U tom smislu postavljeno je istraživanje utjecaja hranidbe smanjenim udjelom bjelančevina i slobodnog izbora krmiva na proizvodne rezultate slobodno držanih zagorskih purana. Purići hranjeni smanjenim udjelom bjelančevina (25% i 23%) u prvih 8 tjedana uzgoja postigli su tjelesne mase u rasponu: muški 1469 do 1483 g, ženski 1201 do 1208 g, što nije mnogo slabije od rezultata postignutih u sličnim uvjetima, ali s hranom bogatijom bjelančevinama. U nastavku uzgoja, od 3 do 6. mjeseca, uz slobodan izbor krmiva i ispašu, purani su postigli sljedeće završne mase: muški P-a = 5882 g , muški P-b = 5752 g, ženski P-a = 3841 g, ženski P-b 3723 g. Hranjenje zrnom ili samljevenim kukuruzom nije imalo značajniji utjecaj na završne tjelesne mase pokusnih purana. Konverzija hrane u prvih osam tjedana uzgoja bila je podjednaka u svim skupinama i kretala se u rasponu od 2,34 do 2,49 kg krmne smjese za kilogram prirasta tjelesne mase. Tijekom uzgoja na otvorenom purani su u obje pokusne skupine konzumirali po kilogramu prirasta približno jednake količine odvojeno ponuđenih krmiva i to kukuruza 4,7 do 5,0 kg a sojine sačme 2,24 do 2,47 kg. Od ukupno konzumiranih krmiva sojina sačma je činila od 31,9 do 33,1 %. Randman klanja i gril obrade bio je u obje pokusne skupine i kod obiju spolova podjednak i iznosio je od 65,6 do 66,6%.Zagorje turkey breed is becoming more and more interesting for so called alternative or organic production of poultry meat in Croatia. Technology of breeding and feeding of Zagorje turkey breed is far from defined, so considerable effort is taken to find as simple and inexpensive solutions as possible. In that sense we set our examination of effects of lowered protein levels in feeds and free-choice feeding on the productive performance of free-range Zagorje turkey. Turkeys fed lower levels of protein (25 and 23% CP) during the first 8 weeks achieved body weight ranging from 1469-1483 g (male birds) and 1201-1208 g (females), which is not much lower than performance of zagorje turkeys fed protein-richer feeds kept in similar conditions. In the following 4-month period, turkeys grazing on pastures with supplemental free-choice feeding, reached a finishing body weight of 5882 g (male group P-a); 5752 g (male group P-b) and 3841 g (female group P-a); 3723 g (female group P-b). Physical form of corn grain (whole grain vs. ground) had no effect on the finishing body weight of Zagorje turkey. FCR over the whole 4-month period was similar in all of the experimental groups (2,34-2,49 kg/kg). Under the conditions of free-range production, turkeys of both experimental groups consumed similar amount of feeds per kg of gain: corn 4,7-5,0 kg and soybean meal 2,24-2,47 kg. Soybean meal consumption was 31.9-33.1 % of total supplemental feed consumed. Dressing percentage was similar in both groups, ranging between 65.6-66.6%

Automatic extraction of learning concepts from exam query repositories

Educational data mining (or EDM) is an emerging interdisciplinary research field concerned with developing methods for exploring the specific and diverse data encountered in the field of education. One of the most valuable data sources in the educational domain are exam query repositories, which are commonly pre-dating modern e-learning systems. Exam queries in those repositories usually lack additional metadata which helps establish relationships between questions and corresponding learning concepts whose adoption is being tested. In this paper we present our novel approach of using data mining methods able to automatically annotate pre-existing exam queries with information about learning concepts they relate to, leveraging both textual and visual information contained in the queries. This enables automatic categorization of exam queries which allows for both better insight into the usability of the current exam query corpus as well as easier reporting of learning concept adoption after these queries are used in exams. We apply this approach to real-life exam questions from a high education university course and show validation of our results performed in consultation with experts from the educational domain

Reduced level of protein and free-choice feeding in Zagorje turkey nutrition

Zagorski puran postaje sve zanimljiviji u razvoju takozvane alternativne ili organske proizvodnje peradskog mesa u Hrvatskoj. Tehnologija uzgoja i hranidbe zagorskih purana još nije definirana i nastoji se iznaći što jednostavnija i jeftinija rješenja. U tom smislu postavljeno je istraživanje utjecaja hranidbe smanjenim udjelom bjelančevina i slobodnog izbora krmiva na proizvodne rezultate slobodno držanih zagorskih purana. Purići hranjeni smanjenim udjelom bjelančevina (25% i 23%) u prvih 8 tjedana uzgoja postigli su tjelesne mase u rasponu: muški 1469 do 1483 g, ženski 1201 do 1208 g, što nije mnogo slabije od rezultata postignutih u sličnim uvjetima, ali s hranom bogatijom bjelančevinama. U nastavku uzgoja, od 3 do 6. mjeseca, uz slobodan izbor krmiva i ispašu, purani su postigli sljedeće završne mase: muški P-a = 5882 g , muški P-b = 5752 g, ženski P-a = 3841 g, ženski P-b 3723 g. Hranjenje zrnom ili samljevenim kukuruzom nije imalo značajniji utjecaj na završne tjelesne mase pokusnih purana. Konverzija hrane u prvih osam tjedana uzgoja bila je podjednaka u svim skupinama i kretala se u rasponu od 2,34 do 2,49 kg krmne smjese za kilogram prirasta tjelesne mase. Tijekom uzgoja na otvorenom purani su u obje pokusne skupine konzumirali po kilogramu prirasta približno jednake količine odvojeno ponuđenih krmiva i to kukuruza 4,7 do 5,0 kg a sojine sačme 2,24 do 2,47 kg. Od ukupno konzumiranih krmiva sojina sačma je činila od 31,9 do 33,1 %. Randman klanja i gril obrade bio je u obje pokusne skupine i kod obiju spolova podjednak i iznosio je od 65,6 do 66,6%.Zagorje turkey breed is becoming more and more interesting for so called alternative or organic production of poultry meat in Croatia. Technology of breeding and feeding of Zagorje turkey breed is far from defined, so considerable effort is taken to find as simple and inexpensive solutions as possible. In that sense we set our examination of effects of lowered protein levels in feeds and free-choice feeding on the productive performance of free-range Zagorje turkey. Turkeys fed lower levels of protein (25 and 23% CP) during the first 8 weeks achieved body weight ranging from 1469-1483 g (male birds) and 1201-1208 g (females), which is not much lower than performance of zagorje turkeys fed protein-richer feeds kept in similar conditions. In the following 4-month period, turkeys grazing on pastures with supplemental free-choice feeding, reached a finishing body weight of 5882 g (male group P-a); 5752 g (male group P-b) and 3841 g (female group P-a); 3723 g (female group P-b). Physical form of corn grain (whole grain vs. ground) had no effect on the finishing body weight of Zagorje turkey. FCR over the whole 4-month period was similar in all of the experimental groups (2,34-2,49 kg/kg). Under the conditions of free-range production, turkeys of both experimental groups consumed similar amount of feeds per kg of gain: corn 4,7-5,0 kg and soybean meal 2,24-2,47 kg. Soybean meal consumption was 31.9-33.1 % of total supplemental feed consumed. Dressing percentage was similar in both groups, ranging between 65.6-66.6%

Interface Development for Electronic Business to Business Communication

Elektroničko poslovanje po mnogima predstavlja budućnost, novu evolucijsku razinu koja bi uskoro mogla u potpunosti zamijeniti klasične načine poslovanja. Veće tvrtke već uviđaju ove činjenice i često ulažu velika sredstva u informatizaciju komunikacije i poslovne suradnje sa svojim partnerima. No male i srednje tvrtke, koje čine 98,8% ukupnog broja tvrtki u Republici Hrvatskoj često nemaju dovoljno sredstava za implementiranje dosadašnjih priznatih rješenja elektroničkog poslovanja. Ovaj rad prikazuje jednu od mogućih strategija ulaska ovakvih tvrtki u elektroničko poslovanje. Moderne otvorene tehnologije vezane uz Internet te aplikacije izvedene na modularnom principu mogu se koristiti kao izgradbeni blokovi za jedan organizirani elektronički sustav, dok su istovremeno svojom niskom cijenom pristupačne za implementaciju i u tvrtkama sa ograničenim sredstvima predviđenim za uključenje u elektroničko poslovanje. Rad se bavi analizom ovih tehnologija te prikazom konkretne primjene tih tehnologija na studijskom primjeru poslovne aplikacije.E-business is considered by many to be the evolution of business collaborations– a new wave which could in time completely replace the classic way of conducting business. Large companies already accept these facts and are investing large amounts of resources to implement the existing solutions for conducting e-business. However, small and medium-sized enterprises (SMEs), representing 98,8% of all the companies registered in Croatia, often cannot accept these solutions because of their large cost of implementation. This thesis shows one of the possible strategies for SMEs to enter the world of electronic business. Modern Internet-related technologies and modul-based applications can be used as building blocks for an organized e-business architecture, and are also very appealling to the SMEs because of their global acceptance and low installation cost. The thesis analyses the feasibility of these technologies, and shows their main advantages on a specific business application example