336 research outputs found
A Spectrally efficient PMR System Utilizing Broadcast Service
Cataloged from PDF version of article.Different trunked Private Mobile Radio (PMR) systems
have been designed over the last several decades, all of which
have symmetric downlink and uplink channel capacities. Due to
this symmetry, these systems may not be spectrally efficient in case
of different types of services, which are specific to PMR systems,
such as group and broadcast calls. In this study, a new asymmetric
trunked PMR system comprising a broadband, wide-area downlink
and a narrowband cellular uplink, is proposed to achieve a
higher spectral efficiency than current digital trunked PMR systems.
This system is spectrally more efficient because in group and
broadcast calls only a single downlink channel has to be allocated
in the downlink part. However, as the number of clusters in the
system increases, this advantage relative to PMR systems is lost,
since the latter can employ frequency reuse. Spectral efficiency of
the proposed asymmetric system (a-PMR) system and a standard
TETRA system are compared using numerical case studies against
different traffic loads and number of clusters. The optimum point,
with respect to number of clusters, up to which the proposed
a-PMR system is more efficient, is determined. It is shown that a
very large PMR user population can be efficiently served using
the proposed a-PMR system. The issues related to implementing
such a system are discussed
q-Analogue of Shock Soliton Solution
By using Jackson's q-exponential function we introduce the generating
function, the recursive formulas and the second order q-differential equation
for the q-Hermite polynomials. This allows us to solve the q-heat equation in
terms of q-Kampe de Feriet polynomials with arbitrary N moving zeroes, and to
find operator solution for the Initial Value Problem for the q-heat equation.
By the q-analog of the Cole-Hopf transformation we construct the q-Burgers type
nonlinear heat equation with quadratic dispersion and the cubic nonlinearity.
In q -> 1 limit it reduces to the standard Burgers equation. Exact solutions
for the q-Burgers equation in the form of moving poles, singular and regular
q-shock soliton solutions are found.Comment: 13 pages, 5 figure
Dynamic Transitions for Quasilinear Systems and Cahn-Hilliard equation with Onsager mobility
The main objectives of this article are two-fold. First, we study the effect
of the nonlinear Onsager mobility on the phase transition and on the
well-posedness of the Cahn-Hilliard equation modeling a binary system. It is
shown in particular that the dynamic transition is essentially independent of
the nonlinearity of the Onsager mobility. However, the nonlinearity of the
mobility does cause substantial technical difficulty for the well-posedness and
for carrying out the dynamic transition analysis. For this reason, as a second
objective, we introduce a systematic approach to deal with phase transition
problems modeled by quasilinear partial differential equation, following the
ideas of the dynamic transition theory developed recently by Ma and Wang
Self-optimization of coverage and capacity based on a fuzzy neural network with cooperative reinforcement learning
Self-organization is a key concept in long-term evolution (LTE) systems to reduce capital and operational expenditures (CAPEX and OPEX). Self-optimization of coverage and capacity, which allows the system to periodically and automatically adjust the key radio frequency (RF) parameters through intelligent algorithms, is one of the most important tasks in the context of self-organizing networks (SON). In this paper, we propose self-optimization of antenna tilt and power using a fuzzy neural network optimization based on reinforcement learning (RL-FNN). In our approach, a central control mechanism enables cooperation-based learning by allowing distributed SON entities to share their optimization experience, represented as the parameters of learning method. Specifically, SON entities use cooperative Q-learning and reinforced back-propagation method to acquire and adjust their optimization experience. To evaluate the coverage and capacity performance of RL-FNN, we analyze cell-edge performance and cell-center performance indicators jointly across neighboring cells and specifically consider the difference in load distribution in a given region. The simulation results show that RL-FNN performs significantly better than the best fixed configuration proposed in the literature. Furthermore, this is achieved with significantly lower energy consumption. Finally, since each self-optimization round completes in less than a minute, RL-FNN can meet the need of practical applications of self-optimization in a dynamic environment
Self-optimized heterogeneous networks for energy efficiency
© 2015, Fan et al.; licensee Springer. Explosive increase in mobile data traffic driven by the demand for higher data rates and ever-increasing number of wireless users results in a significant increase in power consumption and operating cost of communication networks. Heterogeneous networks (HetNets) provide a variety of coverage and capacity options through the use of cells of different sizes. In these networks, an active/sleep scheduling strategy for base stations (BSs) becomes an effective way to match capacity to demand and also improve energy efficiency. At the same time, environmental awareness and self-organizing features are expected to play important roles in improving the network performance. In this paper, we propose a new active/sleep scheduling scheme based on the user activity sensing of small cell BSs. To this end, coverage probability, network capacity, and energy consumption of the proposed scheme in K-tier heterogeneous networks are analyzed using stochastic geometry, accounting for cell association uncertainties due to random positioning of users and BSs, channel conditions, and interference. Based on the analysis, we propose a sensing probability optimization (SPO) approach based on reinforcement learning to acquire the experience of optimizing the user activity sensing probability of each small cell tier. Simulation results show that SPO adapts well to user activity fluctuations and improves energy efficiency while maintaining network capacity and coverage probability guarantees.National Natural Science Foundation of China (No. 61471060); National Major Science and Technology Special Project of China (No. 2013ZX03003016); Funds for Creative Research Groups of China (No. 61421061)
Phytochemical and antioxidant characteristics of medlar fruits (Mespilus germanica L.)
Eleven medlar (Mespilus germanica L.) genotypes sampled from Turkey were analyzed for their fruit weight, fruit dimensions, fruit firmness, ostiole diameter, shape index, skin color, moisture (%), ash (%), reducing sugar (%), crude protein (%), pH, soluble solid content (%), vitamin C (mg/100 g), minerals (P, K, Ca, Mg, Fe, Zn, Mn), total phenolic content and total antioxidant capacity. A wide variation among genotypes on most of the searched parameters was evident. Fruit weight varied from 11.21 g to 33.24 g indicating high variability among genotypes. Determination of antioxidant activities by β-carotene–linoleic acid and 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays resulted in average 80.8%, and 46.6 μg/ml FW DPPH, respectively. The total phenolic contents of eleven medlar genotypes varied from 114 to 293 mg gallic acid equivalent in 100 g fresh weight basis. The medlar fruits were found to be rich in terms of potassium, calcium, phosphorus, magnesium and iron
Capacity analysis of a PMR system with DAB downlink
Several trunked private mobile radio (PMR) systems have been designed over the last decade, most of which have symmetric downlink and uplink channel capacities. These systems may not be spectrally efficient in case of group or broadcast-based voice and data calls, a common feature of PMR systems. We propose a new asymmetric PMR system comprising a wideband OFDM-based downlink and a narrowband uplink, which not only achieves a better spectral efficiency but also can support high bit rate multimedia applications. The system is shown to have high trunking efficiency since all users are assumed to use the pool of channels available in the wideband downlink. In this paper, we study the performance and capacity of a private mobile radio system using a digital audio broadcasting (DAB) downlink. In particular, we study the efficiency of such a system for voice calls using voice activity detection and statistical multiplexing. Moreover, we show that, the efficiency of the system can significantly increase, if the incoming calls, which can not find an available channel, are allowed to wait a certain amount of time before occupying a channel. © 2003 IEEE
Relationship between serum bilirubin levels and metabolic syndrome in patients with schizophrenia spectrum disorders
Objective: We investigated the relationship between serum bilirubin levels and metabolic syndrome (MetS), and the longitudinal effects of baseline serum bilirubin concentrations on MetS in patients with schizophrenia spectrum disorders undergoing atypical antipsychotics. Methods: The sample of this study consisted of 131 patients with schizophrenia spectrum disorders. Waist circumference, blood pressure, and levels of triglycerides, high-density lipoprotein cholesterol, fasting glucose, and insulin were evaluated at baseline and at month six. Serum bilirubin levels were measured at baseline. Serum bilirubin levels of the patients with and without MetS criteria were compared. We also compared patients with high and low bilirubin levels (upper and lower 50th percentiles of serum bilirubin levels) in terms of MetS criteria, MetS frequency, and course of MetS. Results: Serum direct bilirubin levels were more consistently related to MetS and MetS-related variables. The waist circumference and triglyceride criteria for MetS were significantly related to low serum direct bilirubin at baseline; waist circumference and fasting glucose criteria, and insulin resistance were associated with low serum direct bilirubin at follow-up. MetS diagnosis and the presence of the waist circumference criterion were more frequent at the baseline and the follow-up in low bilirubin group. At the end of the follow-up period, the rate of reverse MetS was significantly higher in the high bilirubin group. Conclusion: Our results have suggested that serum direct bilirubin levels showed a more reliable and stable relationship with abdominal obesity for MetS components.in patients with schizophrenia spectrum disorders using antipsychotics. Further studies are required. Copyright © 2017, Korean College of Neuropsychopharmacology
Comparison of growth performance and carcass traits of Japanese quails reared in conventional, pasture, and organic conditions
- …