Background radioactivity of construction materials, raw substance and ready-made CaMoO4 crystals

The results of measurements of natural radioactive isotopes content in different source materials of natural and enriched composition used for CaMoO4 scintillation crystal growing are presented. The crystals are to be used in the experiment to search for double neutrinoless betas-decay of Mo-100.Comment: Contribution to Proc. of Int. Workshop on Radiopure Scintillators RPSCINT 2013, 17-20.09.2013, Kyiv, Ukraine; to be published in EPJ Web of Conferences; 4 pages, 2 figure and 1 table

The Dark Matter Search at KamLAND

Recent data from the DAMA/LIBRA phase-2 confirmed detection of a signal with independent Dark Matter (DM) annual modulation signature at a 12.9 σ CL. Our attempts to verify the DAMA/LIBRA DM observation claim led to construction of underground clean rooms at the KamLAND site and specialized laboratory for production of NaI(Tl) detectors. Current status of these facilities, methods used to grow ultra-low background NaI(Tl) crystals, and radio-purity of the latest NaI(Tl) DM detector prototype are discussed

Polling system with threshold control for modeling of SIP server under overload

The main purpose of this research is the development of the methods for realizing an overload control mechanism on the Session Initiation Protocol servers by the application of polling systems with different service disciplines. The mathematical model is studied by means of numerical methods of the queuing theory and allows analyzing the behavior of different control parameters depending on the load in network of SIP servers. The polling system consists of two queues of finite capacity and implements the threshold control of loading by low-priority customers. The exhaustive and gated service disciplines are studied under Markov assumptions; formulas for calculation of the main probability measures of the polling system are derived. By performing simulations we demonstrate that the polling system with a threshold in the priority queue is a possible solution for loss-based overload control scheme at the SIP server. In some cases from the viewpoint of server utilization we found that the gated discipline is more preferable. © Springer International Publishing Switzerland 2014

Polling system with threshold control for modeling of SIP server under overload

The main purpose of this research is the development of the methods for realizing an overload control mechanism on the Session Initiation Protocol servers by the application of polling systems with different service disciplines. The mathematical model is studied by means of numerical methods of the queuing theory and allows analyzing the behavior of different control parameters depending on the load in network of SIP servers. The polling system consists of two queues of finite capacity and implements the threshold control of loading by low-priority customers. The exhaustive and gated service disciplines are studied under Markov assumptions; formulas for calculation of the main probability measures of the polling system are derived. By performing simulations we demonstrate that the polling system with a threshold in the priority queue is a possible solution for loss-based overload control scheme at the SIP server. In some cases from the viewpoint of server utilization we found that the gated discipline is more preferable. © Springer International Publishing Switzerland 2014

A Simulation Based Analysis of SINR for Device-to-Device Communications in Circular Clusters

In this contribution we address a common scenario for deviceto-device communications. Using the simulation approach we analyze the interference from a single interferer. The proposed model serves as a basis for general analysis featuring more than a single interferer

On distribution of SIR in dense D2D deployments

This paper investigates the signal-to-interference (SIR) performance of dense device-to-device (D2D) deployments that are becoming reality in modern urban environments. By utilizing methods from stochastic geometry, we propose two closed-form approximations for the SIR probability density function, as well as verify them against the corresponding systemlevel simulations. We also discuss the most interesting properties of the introduced models, which yield important conclusions on respective system design. © VDE Verlag GMBH, Berlin, Offenbach, Germany

On distribution of SIR in dense D2D deployments

This paper investigates the signal-to-interference (SIR) performance of dense device-to-device (D2D) deployments that are becoming reality in modern urban environments. By utilizing methods from stochastic geometry, we propose two closed-form approximations for the SIR probability density function, as well as verify them against the corresponding systemlevel simulations. We also discuss the most interesting properties of the introduced models, which yield important conclusions on respective system design. © VDE Verlag GMBH, Berlin, Offenbach, Germany