Session Initiation Protocol (SIP) [1] is adopted as the main signaling protocol for the IP Multimedia Subsystem (IMS). Large deployment of SIP servers in Next Generation Networks (NGN) requires studying the behavior and performance of SIP servers under both normal and overload conditions, which may happen in such networks with a vast number of users. In this paper a measurement-based study is performed to assess SIP proxy server performance under different configurations, and for different underlying transport protocols, for both inter-domain and intra-domain calls. Test results show the effectiveness of configuration and distance on SIP signaling performance. Therefore a great attention must be paid during SIP servers deployment.
The study aims to perform a cluster analysis on the mental health of patients at the cardiac rehabilitation (CR) baseline as well as attendance in sessions and to compare the mental health and healthy behaviors of the samples in an 18-month follow-up. Methods: In the first phase of this longitudinal study, 148 CR patients in western Iran participated from January to April 2016. After completing the standard questionnaires, the participants attended 7-26 exercise sessions on average. Then, the cluster analysis was performed based on anxiety, depression, and the number of attended sessions. During the 18-month phone follow-up, 113 participants answered the other standard instruments. The long-term mental and behavioral consequences were compared among the derived clusters using ANOVA and Tukey post-hoc test. Results: The average age of participants (69.9% male) was 59.3 ± 9.1. The analysis suggested three clusters: (i) patients with medium distress and weak participation, (ii) patients with mild distress and average participation, and (iii) patients with medium distress and good participation. While there was no significant difference among the clusters with regards to healthy behaviors and mortality rate, the difference was significant with regards to psychological distress, somatic symptoms, duration and quality of sleep, and general quality of life (P < 0.05). Conclusion: Initial distress and weak participation of outpatients in CR has more severe long-term somatic and psychological consequences. Screening of increased psychological distress and identification of candidates for failure to adhere to CR at the baseline are considered among the most important responsibilities of the CR team.
Todays, there is an industry demand in telecommunication networks to provide a full-featured, commercially available, scalable and non-proprietary network management solution, where multi-vendor, multi-technology management systems interoperate in an open architecture environment. This paper presents a novel architecture to enable system interaction in management layer, NML-EML, based on MTNM solution package. In this architecture, communication is based on CORBA and JACORB is used as the CORBA interface. Also the MTNM interface software package has been improved so that it could be integrated as south interface for NML softwares and as north interface for EML softwares. As the implementation of this interface is platform independent it could be used in different platforms. Also by adding the communication medium proposed in this paper, the network management software could manage other standard element management systems. Furthermore, the proposed system can be used as a proof of validity and integrity of other interfaces for their considered functions.
In this work, a novel energy efficient multi-objective resource allocation algorithm for heterogeneous cloud radio access networks (H-CRANs) is proposed where the trade-off between increasing throughput and decreasing operation cost is considered. H-CRANs serve groups of users through femtocell access points (FAPs) and remote radio heads (RRHs) equipped with massive multiple input multiple output (MIMO) connected to the base-band unit (BBU) pool via front-haul links with limited capacity. We formulate an energy-efficient multi-objective optimization (MOO) problem with a novel utility function. Our proposed utility function simultaneously improves two conflicting goals as total system throughput and operation cost. With this MOO, we jointly assign the sub-carrier, transmit power, access point (AP)(RRH/FAP), RRH, front-haul link, and BBU. To address the conflicting objectives, we convert the MOO problem into a single-object optimization problem using an elastic-constraint scalarization method. With this approach, we flexibly adjust trade-off parameters to choose between two objective functions.To propose an efficient algorithm, we deploy successive convex approximation (SCA) and complementary geometric programming (CGP) approaches. Finally, via simulation results we discuss how to select the values of trade-off parameters, and we study their effects on conflicting objective functions (i.e., throughput and operation cost in MOO problem). Simulation results also show that our proposed approach can offload traffic from C-RANs to FAPs with low transmit power and thereby reduce operation costs by switching off the under-utilized RRHs and BBUs. It can be observed from the simulation results that the proposed approach outperforms the traditional approach in which each user is associated to the AP (RRHs/FAPs) with the largest average value of signal strength. The proposed approach reduces operation costs by 30% and increases throughput index by 25% which in turn leads to greater energy efficiency (EE).INDEX TERMS 5G, multi-objective optimization problem, elastic-constraints method.
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