QCD phase diagram and charge fluctuations

We discuss the phase structure and fluctuations of conserved charges in two flavor QCD. The importance of the density fluctuations to probe the existence of the critical end point is summarized. The role of these fluctuations to identify the first order phase transition in the presence of spinodal phase separation is also discussed.Comment: 8 pages, 8 figures, plenary talk given at the 19th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions: Quark Matter 2006 (QM 2006), Shanghai, China, 14-20 Nov 200

On the Spectral Efficiency and Fairness in Full-Duplex Cellular Networks

To increase the spectral efficiency of wireless networks without requiring full-duplex capability of user devices, a potential solution is the recently proposed three-node full-duplex mode. To realize this potential, networks employing three-node full-duplex transmissions must deal with self-interference and user-to-user interference, which can be managed by frequency channel and power allocation techniques. Whereas previous works investigated either spectral efficient or fair mechanisms, a scheme that balances these two metrics among users is investigated in this paper. This balancing scheme is based on a new solution method of the multi-objective optimization problem to maximize the weighted sum of the per-user spectral efficiency and the minimum spectral efficiency among users. The mixed integer non-linear nature of this problem is dealt by Lagrangian duality. Based on the proposed solution approach, a low-complexity centralized algorithm is developed, which relies on large scale fading measurements that can be advantageously implemented at the base station. Numerical results indicate that the proposed algorithm increases the spectral efficiency and fairness among users without the need of weighting the spectral efficiency. An important conclusion is that managing user-to-user interference by resource assignment and power control is crucial for ensuring spectral efficient and fair operation of full-duplex networks.Comment: 6 pages, 4 figures, accepted in IEEE ICC 2017. arXiv admin note: text overlap with arXiv:1603.0067

Performance Analysis of Network-Assisted Two-Hop D2D Communications

Network-assisted single-hop device-to-device (D2D) communication can increase the spectral and energy efficiency of cellular networks by taking advantage of the proximity, reuse, and hop gains when radio resources are properly managed between the cellular and D2D layers. In this paper we argue that D2D technology can be used to further increase the spectral and energy efficiency if the key D2D radio resource management algorithms are suitably extended to support network assisted multi-hop D2D communications. Specifically, we propose a novel, distributed utility maximizing D2D power control (PC) scheme that is able to balance spectral and energy efficiency while taking into account mode selection and resource allocation constraints that are important in the integrated cellular-D2D environment. Our analysis and numerical results indicate that multi-hop D2D communications combined with the proposed PC scheme can be useful not only for harvesting the potential gains previously identified in the literature, but also for extending the coverage of cellular networks.Comment: 6 pages and 7 figure

QCD matter within a quasi-particle model and the critical end point

We compare our quasi-particle model with recent lattice QCD results for the equation of state at finite temperature and baryo-chemical potential. The inclusion of the QCD critical end point into models is discussed. We propose a family of equations of state to be employed in hydrodynamical calculations of particle spectra at RHIC energies and compare with the differential azimuthal anisotropy of strange and charm hadrons.Comment: talk at Quark Matter 2005, August 4 - 9, 2005, Budapest, Hungar

Distributed Spectral Efficiency Maximization in Full-Duplex Cellular Networks

Three-node full-duplex is a promising new transmission mode between a full-duplex capable wireless node and two other wireless nodes that use half-duplex transmission and reception respectively. Although three-node full-duplex transmissions can increase the spectral efficiency without requiring full-duplex capability of user devices, inter-node interference - in addition to the inherent self-interference - can severely degrade the performance. Therefore, as methods that provide effective self-interference mitigation evolve, the management of inter-node interference is becoming increasingly important. This paper considers a cellular system in which a full-duplex capable base station serves a set of half-duplex capable users. As the spectral efficiencies achieved by the uplink and downlink transmissions are inherently intertwined, the objective is to device channel assignment and power control algorithms that maximize the weighted sum of the uplink-downlink transmissions. To this end a distributed auction based channel assignment algorithm is proposed, in which the scheduled uplink users and the base station jointly determine the set of downlink users for full-duplex transmission. Realistic system simulations indicate that the spectral efficiency can be up to 89% better than using the traditional half-duplex mode. Furthermore, when the self-interference cancelling level is high, the impact of the user-to-user interference is severe unless properly managed.Comment: 7 pages, 3 figures, accepted in IEEE ICC 2016 - Workshop on Novel Medium Access and Resource Allocation for 5G Network

Thermodynamics of lattice QCD with 3 flavours of colour-sextet quarks

We have been studying QCD with 2 flavours of colour-sextet quarks to distinguish whether it is QCD-like or conformal. For comparison we are now studying QCD with 3 flavours of colour-sextet quarks, which is believed to be conformal in the chiral limit. Here we present the results of simulations of lattice QCD with 3 colour-sextet quarks at finite temperatures on lattices of temporal extent $N_t=4$ and 6, with masses small enough to yield access to the chiral limit. As for the 2-flavour case, we find well-separated deconfinement and chiral-symmetry restoration transitions, both of which move to appreciably weaker couplings as $N_t$ is increased from 4 to 6. If this theory is conformal, we would expect there to be a bulk chiral transition at a fixed coupling. For this reason we conclude that for $N_t=4$ and 6, the chiral and hence the deconfinement transitions are in the strong-coupling domain where the theory is essentially quenched. The similarity between the behaviours of the 2 and 3 flavour theories suggested that the $N_t=4$ and 6 transitions for the 2-flavour theory also lie in the strong-coupling domain. The phase structure of both theories is very similar.Comment: 17 pages Latex(Revtex), 7 postscript figure

A hazai kis- és középvállalkozások elektronikus banki ügyintézéssel kapcsolatos szokásai, attitűdjei és jövőképei (E-banking habits, attitudes and vision of the hungarian small and medium enterprises)

A közelmúltban készült kutatásban a szerzők azt vizsgálták, hogy a kis- és középvállalkozásokban az elektronikus banki ügyintézéssel kapcsolatban milyen szokásaik, attitűdjeik és jövőképeik alakultak ki. A több mint ötszáz KKV-vezetővel készült interjú alapján elmondható, hogy a vállalkozás elektronikus ügyintézéssel kapcsolatos hozzáállása egyáltalán nem, vagy csak nagyon gyenge mértékben hozható összefüggésbe a cég objektív tulajdonságaival, például a létszámmal, az árbevétellel vagy a tevékenységi körrel. Egyértelműen látszik, hogy már az elektronikus banki ügyintézéssel kapcsolatos fogalmak értelmezése is problémát jelent a KKV-vezetők egy részénél. A tudásbeli hiányosságok pedig egyértelműen befolyásolják az e-banking attitűdöt és a használati szokásokat, pedig az elektronikus csatornákat használók elégedettsége minden vizsgált bank ügyfeleinek esetében 80% fölötti értékeket mutat. Így a legfontosabb kérdés az, hogy miként lehetne megértetni a „Szkeptikusok”-kal és a „Mérlegelők”-kel, hogy érdemes a „Haladók” klaszterébe tartozni. Az ügyfélelégedettség sikertényezői egyértelműen a biztonság, az időben és térben széles körű elérhetőség és az egyszerű használat. A válaszadók jövőképe szerint a banki szolgáltatások igénybevétele egyre inkább eltolódik majd az elektronikus csatornák irányába. Jelen cikkben a kutatás legfontosabb tanulságait mutatják be a szerzők. _________ The authors’ research was conducted to explore the ebanking attitudes, habits and vision of small and medium enterprises. By the interviews of more than 500 managers of SMEs, it is concluded that e-banking attitudes are not, or not significantly related to the objective characteristics of the enterprises, e.g. to the number of employment, the revenues or its activities. It became clear, that the interpretation of the specific e-banking terms means an important problem for some managers. The deficiencies of knowledge have direct effects on e-banking attitude and the use of electronic banking methods of the enterprises, although the value of the satisfaction level is above 80% among the customers of each examined banks. Thus, the main objective is to explain to the “Scepticals” and the “Considerers” the benefits of the “Progressives” cluster. The most important success factors of customer satisfaction are safety, availability in time and space and ease of use. According to the vision of the respondents, banking services will probably be shifted towards e-channels. In this study, the most important findings of our researches were summarized