Resource Allocation for Energy-Efficient Device-to-Device Communication in 4G Networks

Device-to-device (D2D) communications as an underlay of a LTE-A (4G) network can reduce the traffic load as well as power consumption in cellular networks by way of utilizing peer-to-peer links for users in proximity of each other. This would enable other cellular users to increment their traffic, and the aggregate traffic for all users can be significantly increased without requiring additional spectrum. However, D2D communications may increase interference to cellular users (CUs) and force CUs to increase their transmit power levels in order to maintain their required quality-of-service (QoS). This paper proposes an energy-efficient resource allocation scheme for D2D communications as an underlay of a fully loaded LTE-A (4G) cellular network. Simulations show that the proposed scheme allocates cellular uplink resources (transmit power and channel) to D2D pairs while maintaining the required QoS for D2D and cellular users and minimizing the total uplink transmit power for all users.Comment: 2014 7th International Symposium on Telecommunications (IST'2014

Full analysis of a high-bandwidth microring-based PIN modulator

This study presents a new simulation strategy for a high-speed microring-based PIN modulator using the finite element method. It includes dc and transient simulations of the electro-optical behavior of the device. Variations in the effective refractive index and their effect on the optical output fields are determined by applying a reverse bias voltage pulse to the device. The frequency responses have been calculated for the microring modulator and 3 dB bandwidth. Calculations show a 3 dB bandwidth of over 115 GHz for a ring with a radius of 8 µm and a width of 0.5 µm at -7 V biasing voltage

Response time of a direct injection type-variable-rate sprayer

An approach to developing variable-rate sprayer technologies is to install electronic control systems on conventional sprayers.  This study introduces a direct injection type electronic solution concentration control system.  This control system was installed on a field sprayer, and then a map-based variable-rate sprayer was developed.  The control system consisted of a chemical tank, a chemical metering pump, the metering pump’s driver, the metering pump’s speed sensor, the implement’s travelling speed sensor, an Electronic Control Unit (ECU), a GPS receiver and a mixing unit.  The metering pump discharge was measured at different carrier liquid (water) working pressures (3, 4 and 5 bar) and different chemical metering pump shaft speed (100, 200, 300 and 400 r/min, i.e. pump’s working range).  Data analysis showed that the effect of metering pump speed, sprayer working pressure and their interaction was significant (P < 0.001) on the metering pump’s discharge.  Metering pump’s discharge function and the independent variables of pump speed and working pressure were calculated.  In order to determine the system response time, an electromotor replaced on the right hand front wheel of the tractor (the implement’s traveling speed sensor location), thus simulating the implement’s movement.  An Electrical Conductivity (EC) sensor was mounted on rightmost nozzle of the boom.  The chemical tank was filled with thick brine. The system response time was measured at different working pressures (3, 4 and 5 bar), travelling speeds (3, 6 and 9 km h-1) and spraying concentration change rates (2, 3 and 4 L ha-1).  The working pressure was the only variable with a significant effect on the response time at the 1% level.  The mean of response times were 25.8, 22.8 and 17.9 s at 3, 4 and 5 bar working pressures, respectively.  The look-ahead firmware of the system was designed using the determined response time.   Keywords: direct -injection system; variable-rate sprayer; system response tim

Factors affecting energy consumption and productivity in greenhouses

Aim of study: To investigate the impact factors affecting the greenhouse environment on energy consumption and productivity.Area of study: Alborz province of Iran during the period 2018–2020.Material and methods: In this study, 18 active units of greenhouse owners in Alborz province of Iran that had necessary standards were identified. Then, upper and lower amplitudes of the variables affecting productivity and energy consumption in greenhouses were calculated using a type-2 fuzzy neural network, Matlab 2017 software. Area, temperature, energy exchange, environmental evapotranspiration and relative humidity were studied as indicators.Main results: With each unit of temperature, energy consumption and productivity increased by 0.737% and 0.741%, respectively; with each unit of energy exchange, they increased by 0.813% and 0.696%, respectively; with each unit of evaporation and transpiration of the environment, they increased by 0.593% and 0.869%, respectively; and with each unit of humidity, they increased by 0.398% and 0.509%, respectively.Research highlights: The factors affecting the greenhouse environment such as area, temperature, evapotranspiration and relative humidity had a significant effect on productivity in studying greenhouses and therefore increasing their productivity. According to the results, the model’s ability in energy consumption was better than that for energy efficiency prediction. Also, greenhouse ranking was done by FAHP method

Optimization of shape and direction of the greenhouse using gray wolf algorithm

Greenhouse structure is one of the most important factors in the greenhouse industry; increasing energy prices is a major challenge for greenhouse owners. Greenhouses should be so designed that they have high light transmission especially in winter and at the same time satisfy the requirements of the construction cost and the safety against the loads which may be imposed upon them. In this research, the goal is to optimize the shape and direction of the greenhouse to minimize the energy required for heating. The design parameters in this work are determined for two different types of greenhouses with the target functions, with the gray wolf optimization method. Optimization of energy consumption for different models of greenhouse and different materials was performed using gray wolf algorithm. Accordingly, in each case, the best design parameters and greenhouse model were obtained and energy consumption was calculated in summer and winter. At the end of the study, the gray wolf algorithm was compared with the particle swarm algorithm, which indicated that the gray wolf algorithm was powerful

Effect of Pre and Post Weaning Diet Quality on Puberty Age and Tail Measures in Kurdish Female Lambs

To determine the value of pre and post weaning nutrition on puberty age, some hormonal concentrations and tail measures in ewe lambs, a total of 40 clinically health Kurdish female lambs (30±8.6 d and weighing 10.2±3.4 kg) were randomly allocated to one of two experimental diets in pre-weaning period: high quality diet (HQD, 2.50 Mcal ME/kg dry matter (DM) and 148 g CP/kg DM) or low quality diet (LQD, 2.02 Mcal ME/kg DM and 87 g CP/kg DM). At weaning, one half of lambs from each group was randomly separated and assigned to HQD or LQD. So there were four treatment groups in post-weaning period: H-H (HQD pre- and post-weaning); H-L (HQD pre-weaning and LQD post-weaning); L-H (LQD pre-weaning and HQD post-weaning) and L-L (LQD pre and post-weaning, control group). Within the post-weaning, serum progesterone concentrations was greater for ewe lambs fed at H-H group than for other groups (P<0.05). Serum insulin concentration was affected by the diet quality at both periods (P<0.05). Leptin concentration was affected by treatment and ewe lambs of L-H group had higher leptin concentrations (P<0.05). Diet plan in the pre-pubertal period was affected tail measures in 120 and 210 days of ages (P<0.05)

An Extensive Volar Forearm Laceration – The Spaghetti Wrist: A Systematic Review

PURPOSE: ‘Spaghetti wrist’ is an extensive laceration that involves multiple structures in the volar wrist, including tendons, nerves and arteries. This injury is frequently encountered in trauma units, but despite its complex nature, management is often handled by junior surgeons. Furthermore, the guidance on how to approach these injuries is limited, with a relatively poor evidence base on management and outcomes. METHODS: In this article, we perform a systematic review of the literature on the management and outcomes of the spaghetti wrist injury. Patient demographics, definitions of spaghetti wrist, mechanism of injury, operative and rehabilitative techniques and surgical outcomes are discussed. RESULTS: Results from this study show significant physical, functional, psychological and financial impacts of spaghetti wrist injuries. Operative technique appears relatively consistent; even though reporting of injuries and outcomes was heterogeneous, no current classification system is in common usage. CONCLUSIONS: An increased focus on the standardisation of assessment, management and rehabilitation and on overcoming the obstacles to care will serve as a guidance to the operative and post-operative management of the spaghetti wrist injury. The use of a single definition and classification system has been proposed to standardise outcome measures and improve inter-observer reliability

Effect of body change positions on endotracheal tube cuff pressure in patients with head injury treated with mechanical ventilation

Background: Maintaining endotracheal tube cuff pressure in the normal range of 25-30 cmH2o plays an important role in the prevention of related complications. Objective: The present study aimed to determine the effect of body change position on level of endotracheal tube cuff pressure in patients with head trauma under mechanical ventilation admitted in ICUs. Methods: This quasi-experimental study was implemented on 30 patients with head injury under mechanical ventilation who admitted in ICUs in 2014. Available method was used for sampling. The mean of endotracheal cuff pressure was measured in 6 different body positions in the two-hour intervals using standard manometer, immediately before, immediately after, 15 minutes and 2 hours after the change positions. Data was analyzed using Chi-square, t and Bonferroni tests. Findings: The mean of endotracheal cuff pressure in the left and right lateral position with an angle of 30 degrees and head to the body (Respectively 31.5±0.68 and 34.1±0.68 cmH2o) and also the left and right lateral and a 45-degree angle to the body at the end of the period of 15 minutes and 2 hours after change positions was higher than the normal range (Respectively 31.9±0.92 and 30.4±1.5 cmH2o). In all cases, the mean of pressure differences were statistically significant (p<0.001) Conclusion: According to the unnatural changes in endotracheal tube cuff pressure due to body change positions, it is suggested that after changing position of the patient, measure the cuff pressure and correct it if it’s necessary. Keywords: Head Injury, Mechanical Ventilation, Body Position, Endotracheal Tube Cuff Pressur

On Security and reliability using cooperative transmissions in sensor networks

Cooperative transmissions have received recent attention and research papers have demonstrated their benefits for wireless networks. Such benefits include improving the reliability of links through diversity and/or increasing the reach of a link compared to a single transmitter transmitting to a single receiver (single-input single-output or SISO). In one form of cooperative transmissions, multiple nodes can act as virtual antenna elements and provide diversity gain or range improvement using space-time coding. In a multi-hop ad hoc or sensor network, a source node can make use of its neighbors as relays with itself to reach an intermediate node with greater reliability or at a larger distance than otherwise possible. The intermediate node will use its neighbors in a similar manner and this process continues till the destination is reached. Thus, for the same reliability of a link as SISO, the number of hops between a source and destination may be reduced using cooperative transmissions as each hop spans a larger distance. However, the presence of ma-licious or compromised nodes in the network impacts the benefits obtained with cooperative transmissions. Using more relays can increase the reach of a link, but if one or more relays are malicious, the transmission may fail. However, the relationships between the number of relays, the number of hops, and success probabilities are not trivial to determine. In this paper, we analyze this problem to understand the conditions under which cooperative transmissions fare better or worse than SISO transmissions. We take into consideration additional parameters such as the path-loss exponent and provide a framework that allows us to evaluate the conditions when cooperative transmissions are better than SISO transmissions. This analysis provides insights that can be employed before resorting to simulations or experimentation. © Springer Science+Business Media, LLC 2012