Half-Duplex Relaying for the Multiuser Channel

This work focuses on studying the half-duplex (HD) relaying in the Multiple Access Relay Channel (MARC) and the Compound Multiple Access Channel with a Relay (cMACr). A generalized Quantize-and-Forward (GQF) has been proposed to establish the achievable rate regions. Such scheme is developed based on the variation of the Quantize-and-Forward (QF) scheme and single block with two slots coding structure. The results in this paper can also be considered as a significant extension of the achievable rate region of Half-Duplex Relay Channel (HDRC). Furthermore, the rate regions based on GQF scheme is extended to the Gaussian channel case. The scheme performance is shown through some numerical examples.Comment: 7 pages, 4 figures, conference pape

Analysis and modeling of rail maintenance costs

Railroad maintenance engineering plays an important role on availability of roads and reducing the cost of railroad incidents. Rail is of the most important parts of railroad industry, which needs regular maintenance since it covers a significant part of total maintenance cost. Any attempt on optimizing total cost of maintenance could substantially reduce the cost of railroad system and it can reduce total cost of the industry. The paper presents a new method to estimate the cost of rail failure using different cost components such as cost of inspection and cost of risk associated with possible accidents. The proposed model of this paper is used for a real-world case study of railroad transportation of Tehran region and the results have been analyzed

RS-Based MIMO-NOMA Systems in Multicast Framework

This chapter presents a novel scheme that integrates the rate-splitting (RS) technique in Multiple Input Multiple Output (MIMO) systems with non-orthogonal multiple access (NOMA) to improve performance and capacity in wireless communication systems under imperfect channel state information at the transmitter (CSIT) and in overloaded regimes. The proposed approach addresses a general and realistic scenario, incorporating both unicast and multicast users, aiming to increase system throughput through the optimization of precoding vectors and power allocation. A generic power allocation optimization technique is introduced, which can be employed for maximizing both the minimum-rate and sum-rate, focusing on the rate of the weakest user within each group per cluster. To tackle the non-convex nature of the problems, the proposed technique leverages the WMMSE-rate relationship and an alternating optimization (AO) algorithm, transforming the problem into a convex one. The chapter provides a comprehensive analysis of the proposed scheme, offering a tutorial background and presenting novel insights for an enhanced understanding

Open sub-granting radio resources in overlay D2D-based V2V communications

Capacity, reliability, and latency are seen as key requirements of new emerging applications, namely vehicle-to-everything (V2X) and machine-type communication in future cellular networks. D2D communication is envisaged to be the enabler to accomplish the requirements for the applications as mentioned earlier. Due to the scarcity of radio resources, a hierarchical radio resource allocation, namely the sub-granting scheme, has been considered for the overlay D2D communication. In this paper, we investigate the assignment of underutilized radio resources from D2D communication to device-to-infrastructure communication, which are moving in a dynamic environment. The sub-granting assignment problem is cast as a maximization problem of the uplink cell throughput. Firstly, we evaluate the sub-granting signaling overhead due to mobility in a centralized sub-granting resource algorithm, dedicated sub-granting radio resource (DSGRR), and then a distributed heuristics algorithm, open sub-granting radio resource (OSGRR), is proposed and compared with the DSGRR algorithm and no sub-granting case. Simulation results show improved cell throughput for the OSGRR compared with other algorithms. Besides, it is observed that the overhead incurred by the OSGRR is less than the DSGRR while the achieved cell throughput is yet close to the maximum achievable uplink cell throughput

Assessment and Spatial Distribution of Mineral Groundwater Quality in Ardabil Province, Iran

Background: The present study was conducted to determine the quality of mineral ground waters and analyze their spatial distribution in Ardabil Province of Iran.Methods: This descriptive analytical study was carried out on natural mineral water wells in Ardabil Province over one year. Samples of water were taken from a total of 44 wells in this province every season, from April 2016 to February 2017. They were then transferred to Khak Azmay-e Moghan Laboratory and their Total Dissolved Solids (TDS), chloride, calcium, magnesium, sulfate, sodium and bicarbonate were measured based on the instructions presented in Standard Methods. The Ground Water Quality Index (GWQI) was then determined based on the measured parameters. The spatial distribution of the ground waters based on the GWQI was then also determined in a Geographic Information System (GIS).Results: The GWQI varied extensively in the natural mineral water wells of Ardabil Province, from 24.88 to 312.58. The best physicochemical quality based on the GWQI was observed in Hammam-e Sangi and the poorest quality in Saghezji-Mardaneh. According to the index, 2.5% of the wells were of very good quality, 30% were of good quality, 32% of moderate quality, 13.5% of poor quality and 22% were of inappropriate quality.Conclusions: According to the results, the most important quality problems included high levels of TDS, chlorine and sulfate and low pH values. Considering that these wells supply people’s drinking water in this region, consumers should be warned of their water quality, and purification procedures should also be carried out to allow the hygienic use of these valuable resources

Assessment and Spatial Distribution of Mineral Groundwater Quality in Ardabil Province, Iran

Background: The present study was conducted to determine the quality of mineral ground waters and analyze their spatial distribution in Ardabil Province of Iran.Methods: This descriptive analytical study was carried out on natural mineral water wells in Ardabil Province over one year. Samples of water were taken from a total of 44 wells in this province every season, from April 2016 to February 2017. They were then transferred to Khak Azmay-e Moghan Laboratory and their Total Dissolved Solids (TDS), chloride, calcium, magnesium, sulfate, sodium and bicarbonate were measured based on the instructions presented in Standard Methods. The Ground Water Quality Index (GWQI) was then determined based on the measured parameters. The spatial distribution of the ground waters based on the GWQI was then also determined in a Geographic Information System (GIS).Results: The GWQI varied extensively in the natural mineral water wells of Ardabil Province, from 24.88 to 312.58. The best physicochemical quality based on the GWQI was observed in Hammam-e Sangi and the poorest quality in Saghezji-Mardaneh. According to the index, 2.5% of the wells were of very good quality, 30% were of good quality, 32% of moderate quality, 13.5% of poor quality and 22% were of inappropriate quality.Conclusions: According to the results, the most important quality problems included high levels of TDS, chlorine and sulfate and low pH values. Considering that these wells supply people’s drinking water in this region, consumers should be warned of their water quality, and purification procedures should also be carried out to allow the hygienic use of these valuable resources

Modulation of Hypoxia-Induced Chemoresistance to Polymeric Micellar Cisplatin: The Effect of Ligand Modification of Micellar Carrier Versus Inhibition of the Mediators of Drug Resistance

Hypoxia can induce chemoresistance, which is a significant clinical obstacle in cancer therapy. Here, we assessed development of hypoxia-induced chemoresistance (HICR) against free versus polymeric cisplatin micelles in a triple negative breast cancer cell line, MDA-MB-231. We then explored two strategies for the modulation of HICR against cisplatin micelles: a) the development of actively targeted micelles; and b) combination therapy with modulators of HICR in MDA-MB-231 cells. Actively targeted cisplatin micelles were prepared through surface modification of acetal-poly(ethylene oxide)-poly(-carboxyl- -caprolactone) (acetal-PEO-PCCL) micelles with epidermal growth factor receptor (EGFR)-targeting peptide, GE11 (YHWYGYTPQNVI). Our results showed that hypoxia induced resistance against free and cisplatin micelles in MDA-MB-231 cells. A significant increase in micellar cisplatin uptake was observed in MDA-MB-231 cells that overexpress EGFR, following surface modification of micelles with GE11. This did not lead to increased cytotoxicity of micellar cisplatin, however. On the other hand, the addition of pharmacological inhibitors of key molecules involved in HICR in MDA-MB-231 cells, i.e., inhibitors of hypoxia inducing factor-1 (HIF-1) and signal transducer and activator of transcription 3 (STAT3), substantially enhanced the cytotoxicity of free and cisplatin micelles. The results indicated the potential benefit of combination therapy with HIF-1 and STAT3 inhibitors in overcoming HICR to free or micellar cisplatin