Accounting for Taste: Using profile similarity to improve recommender systems

Recommender systems have been developed to address the abundance of choice we face in taste domains (films, music, restaurants) when shopping or going out. However, consumers currently struggle to evaluate the appropriateness of recommendations offered. With collaborative filtering, recommendations are based on people's ratings of items. In this paper, we propose that the usefulness of recommender systems can be improved by including more information about recommenders. We conducted a laboratory online experiment with 100 participants simulating a movie recommender system to determine how familiarity of the recommender, profile similarity between decision-maker and recommender, and rating overlap with a particular recommender influence the choices of decision-makers in such a context. While familiarity in this experiment did not affect the participants' choices, profile similarity and rating overlap had a significant influence. These results help us understand the decision-making processes in an online context and form the basis for user-centered social recommender system design

Oxygen Bonding to Haemoglobin. 17O NMR Spectrum A Second Look

It was found that the upper concentration limit in detecting the oxygen-17 NMR signal from ordinary solvent water in solutions of oxyhaemoglobin is about 12 · 10-3 M (in haem). From samples of oxyhaemoglobin prepared with oxygen gas enriched to 62° /o in 170 a signal could be detected within a few days in spite of higher protein concentrations. Such signals increased in couple of weeks up to three times. However, within this period of time the sealed, dissolved oxyhaemoglobin became deoxygenated showing the characteristic colour change, while the NMR 170 signal persisted. The pressure above such sealed solutions diminished and the mass-spectroscopic analyses showed two- to threefold enrichment in 170 of solvent water after the deoxy-conversion, while in the gas phase oxygen ¥,Tas replaced by carbon dioxide. There is no deoxy-conversion in samples prepared under sterile conditions or in presence of sodium azide (equimolar with haem). It is concluded that owing to bacterial contamination in haemoglobin solutions prepared under ordinary conditions oxygen from the gas-phase is being reduced into water through bacterial metabolism. Thus, the observed 170 NMR signals were due to the solvent water enriched in 170. A former paper* claiming detection of 170 NMR signal from oxygen bound to haemoglobin is thus invalidated

Oxygen Bonding to Haemoglobin. 17O NMR Spectrum A Second Look

It was found that the upper concentration limit in detecting the oxygen-17 NMR signal from ordinary solvent water in solutions of oxyhaemoglobin is about 12 · 10-3 M (in haem). From samples of oxyhaemoglobin prepared with oxygen gas enriched to 62° /o in 170 a signal could be detected within a few days in spite of higher protein concentrations. Such signals increased in couple of weeks up to three times. However, within this period of time the sealed, dissolved oxyhaemoglobin became deoxygenated showing the characteristic colour change, while the NMR 170 signal persisted. The pressure above such sealed solutions diminished and the mass-spectroscopic analyses showed two- to threefold enrichment in 170 of solvent water after the deoxy-conversion, while in the gas phase oxygen ¥,Tas replaced by carbon dioxide. There is no deoxy-conversion in samples prepared under sterile conditions or in presence of sodium azide (equimolar with haem). It is concluded that owing to bacterial contamination in haemoglobin solutions prepared under ordinary conditions oxygen from the gas-phase is being reduced into water through bacterial metabolism. Thus, the observed 170 NMR signals were due to the solvent water enriched in 170. A former paper* claiming detection of 170 NMR signal from oxygen bound to haemoglobin is thus invalidated

Emergence of scale-free leadership structure in social recommender systems

The study of the organization of social networks is important for understanding of opinion formation, rumor spreading, and the emergence of trends and fashion. This paper reports empirical analysis of networks extracted from four leading sites with social functionality (Delicious, Flickr, Twitter and YouTube) and shows that they all display a scale-free leadership structure. To reproduce this feature, we propose an adaptive network model driven by social recommending. Artificial agent-based simulations of this model highlight a "good get richer" mechanism where users with broad interests and good judgments are likely to become popular leaders for the others. Simulations also indicate that the studied social recommendation mechanism can gradually improve the user experience by adapting to tastes of its users. Finally we outline implications for real online resource-sharing systems

Recommender Systems

The ongoing rapid expansion of the Internet greatly increases the necessity of effective recommender systems for filtering the abundant information. Extensive research for recommender systems is conducted by a broad range of communities including social and computer scientists, physicists, and interdisciplinary researchers. Despite substantial theoretical and practical achievements, unification and comparison of different approaches are lacking, which impedes further advances. In this article, we review recent developments in recommender systems and discuss the major challenges. We compare and evaluate available algorithms and examine their roles in the future developments. In addition to algorithms, physical aspects are described to illustrate macroscopic behavior of recommender systems. Potential impacts and future directions are discussed. We emphasize that recommendation has a great scientific depth and combines diverse research fields which makes it of interests for physicists as well as interdisciplinary researchers.Comment: 97 pages, 20 figures (To appear in Physics Reports

Followee recommendation in twitter using fuzzy link prediction.

In social networking sites, it is useful to receive recommendations about whom to contact or follow. These recommendations not only allow to establish connections with people one might already know in real life, but also with people or users that have similar interests or are potentially interesting. We propose an approach that tackles contact (followee) recommendation in Twitter by means of fuzzy logic. This fuzzy approach handles recommendation as a link prediction problem and uses three types of similarity between a pair of users: tweet similarity, followee id similarity, and followee tweet similarity. These similarities are calculated by extracting user profiles. These profiles are, in turn, obtained by considering Twitter as a heterogeneous information network. To test our approach, we crawled a repository of 6,000 users and 2 million tweets, and we measured accuracy by comparing our results with the actual followee lists of the users. These results, which are also compared against the results given by state-of-the-art methods, show a high accuracy. Other advantages of the fuzzy system include a self-explanatory capability and the ability to produce a non-binary friendship value

Institutional Positioning in Growth States: Influencers and Strategies of Enrollment Managers at Public Research Universities

Enrollment management practices, principles, and administrative structure are changing the behavior of the contemporary university. Through an examination of public Carnegie Research Intensive and Extensive universities in states anticipating growth in the high school graduate population, the study seeks to provide a greater understanding of enrollment management. The theoretical lenses of institutional theory (DiMaggio & Powell, 1983), resource dependence (Tolbert, 1985), and academic capitalism (Slaughter & Leslie, 1997; Slaughter & Rhoades, 2004), are employed to develop a new view of administrative behavior in current enrollment management organizations. In depth interviews with the individuals leading enrollment efforts at selected universities identify the enrollment manager as an administrator, educator, and entrepreneur. These individuals operate in complex political environments balancing their personal educational philosophies with the needs of their universities. Comprehensive reviews of the strategic enrollment plans at study universities reveal three main goals across all institutions: maintaining financial stability, increasing student and institutional quality, and increasing student diversity. Administrative behavior shows that all three goals are not treated equally and that revenue enhancement activities are prioritized. The administrative behaviors detailed in this study suggest a new ideology related to revenue enhancement for public higher education in the United States

Social recommender systems - capitalising on virtual social networks for better recommendations

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Analysis of cost-selected element of business infrastructure

Bakalářská práce se zabývá analýzou hospodárnosti vybraného prvku podnikatelské infrastruktury ve statutárním městě Hradec Králové. První část práce je věnována konkurenceschopnosti regionů. Druhá část práce je zaměřena na základní charakteristiku prvků podporujících podnikatelskou infrastrukturu. V další části je proveden podrobný popis Technologického centra Hradec Králové a popis jeho činností. Poslední část práce je zaměřena na zhodnocení hospodárnosti Technologického centra Hradec Králové.This thesis analyzes the efficiency of the selected element of business infrastructure in the statutory city of Hradec Kralove. The first part deals with region competitiveness, the second part focuses on the basic characteristics of the elements supporting the business infrastructure. The next section describes the Technology Centre in Hradec Kralove and its activities in details. The last part focused on cost-effectiveness evaluation of the Technology Centre in Hradec Kralove.Ústav ekonomiePředstavení bakalářské práce a jejich cílů. Představení Technologického centra v Hradci Králové. hospodárnost Technologického centra. Komparace s VTPUP. Rekapitulace výsledků. Zodpovězení otázek vedoucího práce a doplňujících otázek

Analysis of Risk Management

Tato diplomová práce se zabývá projektovým managementem, konkrétně oblastí řízení rizik. V práci je pojednáno o procesech řízení projektů, o rizicích a jejich managementu. Na vybraném projektu z oblasti podnikatelských inkubátorů a jejich výstavby je zhodnoceno vzniklé riziko a porovnáno se skutečností.This thesis deals with project management, namely the areas of risk management. The paper discusses the processes of project management, of the risks and their management. On a selected project on business incubators and their construction is evaluated and compared the resulting risk to the facts.Ústav podnikové ekonomiky a managementuStudent seznámil komisi s obsahem a cílem své diplomové práce. Student seznámil komisi se závěry práce a odpověděl na otázky položené vedoucím práce a oponentem:Ot.č.1 : Vysvětlete pojem celková rizikovost projektu. Ot.č.2 : Která rizika z uvedených možných rizik projektu ( subkapit. 5.2. ) považujete za nejvýznamějaí ? Podle čeho jste zpravoval tabulku č. 7 na straně 49