Power-trading in wireless communications: a cooperative networking business model

Managing the power resource in battery operated wireless devices is very crucial for extending the lifetime, here we propose the concept of power trading in wireless communications. We present a business model using sealed bid procurement auction based game theory for power-trading in cooperative wireless communication with quality of service (QoS) constraints. We formulate the problem as an auction in a buyer's market sequentially/repeatedly played with a single source and a multiple relay network. The source, in-need of cooperation of a relay due to lack of battery power to communicate with the destination, broadcasts a cooperation-request specifying its QoS requirements. The QoS that we consider here are the bit error rate and the total delay associated with relaying the source data. The relays respond with their bids in terms of Euros/bit, and the source selects the best relay based on the bids. The relays compete with each other to win the game and profit from power trading. Each relay updates its pricing index via reinforcement learning to win the game during successive bidding intervals of the repeated game. Based on this model our results show that the relay node with the best features such as a better wireless channel and a better geographical position with respect to the source and destination nodes has a better chance of winning the game, and hence giving rise to a dominant strategy. More importantly, we show that the gains from the wireless channels can be converted into economic profits which is an attractive feature of the proposed business model for power trading

Presenteeism and Its Conceptualization: A Literature Review

Abstract Presenteeism is a comparatively new phenomenon in the study of occupational behaviors which evolved throughout the past few decades. Increasing interest in managing presenteeism effectively emerged as a new source of competitive advantage in current organizations. With definitional confusion, the most scholarly conception of presenteeism involves the employee’s attending to work while being ill. However, the definition has been more recently extended to include other conditions and events that limit productivity. Now focus is moving from single dimension to multiple dimensions of presenteeism. Accordingly, this conceptual paper traces the development of interest in presenteeism with consideration of its various conceptualizations which are important theoretically and practically. The paper may be useful to those who are interested in understanding the concept of presenteeism for future research studies. Key Words: Conceptualization, Presenteeism, Sickness Presenteeis

Solid-Like Electrolyte Based on Cellulosic Biomass Materials for Cost Effective and Eco-Friendly Lithium Ion Batteries Function as a Sustainable Energy Source

The demand for the sustainable energy sources has increased due to the environmental issues, durability and cost. Lithium ion rechargeable batteries (LiBs) are widely known as a renewable energy source. LiBs can be converted to effective sustainable energy sources when they are modified to acquire the criterias of sustainable energy sources other than rechargeability. In the present, there is an inclination to develop all-solid state and solid-like electrolytes for LiBs due to the environmental and safety issues resulted by liquid electrolytes. In this work, an experiment was carried out to design a lithium ion battery using a solid-like electrolyte based on cellulosic biomass. Cellulosic biomass is very abundant, low cost and eco-friendly. Cellulose is a crucial extractable material of cellulosic biomass and carboxymethyl cellulose can be synthesized from cellulose. In here, one component of the electrolyte synthesized is lithium dichlorocarboxymethyl cellulose (LiCMC) using cellulose, LiOH and trichloroacetic acid. Tricholoacetic acid can be extracted from disinfected byproducts in water. LiCMC has various advantages over typical sodium carboxymethyl cellulose. LiCMC has additional chlorine atoms and lithium ions which directly promote the segmental motion diffusion of lithium ions. The prepared LiCMC was crosslinked with β-cyclodextrin (BCD) using citric acid. In here, BCD is very efficient because it is environmentally friendly and its cavities enhance the lithium ion conduction. Another component in this electrolyte is LiCMC grafted mesoporous silica (MS). The cavities of MS enhance the lithium ion conductivity and the robustness of MS improves the durability of the battery. In the preparation of the electrolyte, citric acid cross linked LiCMC-BCD and LiCMC grafted MS were incorporated together. The resulted hydrogel was dipped in LiCl aqueous solution and then it was used as the electrolyte. Graphite/graphene oxide (GO) composite was used as the anode and Cobalt oxide-GO hydrogel was used as the cathode of the prepared cell. The performance of the assembled cell was analyzed using charge-discharge curves. The assembled cell showed an initial current density of 1.5 mA cm-2 and maximum current density of 4.5 mA cm-2 in charging and initial current density of 0.90 mA cm-2 and minimum current density of 0.20 mA cm-2 in discharging. The synthesized materials mentioned in above were analyzed using FTIR-ATR data. The eco-friendliness, cost effectiveness of the materials chosen in cell preparation and the desirable cell performance induce the viability to develop LiBs as sustainable energy sources.Keywords: Sustainable energy sources, Cellulosic biomass, Solid-like electrolytes, Lithium dichlorocarboxymethyl cellulose, β-cyclodextri

Analysis of Linear Receivers in a Target SINR Game for Wireless Cognitive Networks

Abstract-Signal to Interference plus Noise Ratio (SINR) is a key parameter for every user in a wireless network. Different users with heterogeneous QoS requirements have different target SINR requirements. In cognitive radio (CR) networks, secondary users try to access the available spectrum in order to make successful transmissions. However, without proper regulation, they may transmit at their maximum power to achieve the highest possible SINR, which can be even worse than the current wasteful static spectrum utilization. A target SINR game (TSG) is a powerful tool to regulate each secondary user's behavior, provide them with decent SINRs (i.e. close to their target SINRs) and simultaneously limit the interference they cause to primary users and other secondary users. The goal of this paper is to analyze the performance of the Matched Filter (MF) receiver and the linear MMSE receiver (LMMSE) in a TSG. As expected, the LMMSE shows several advantages in performance over the MF

The GP Tests of Competence assessment: which part best predicts fitness to practise decisions?

BACKGROUND: The General Medical Council (GMC) conducts Tests of Competence (ToC) for doctors referred for Fitness to Practise (FtP) issues. GPs take a single best answer knowledge test, an Objective Structured Clinical Examination (OSCE), and a Simulated Surgery (SimSurg) assessment which is a simulated GP consultation. The aim of this study was to examine the similarities between OSCEs and SimSurg to determine whether each assessment contributed something unique to GP ToCs. METHODS: A mixed methods approach was used. Data were collated on 153 GPs who were required to undertake a ToC as a part of being investigated for FtP issues between February 2010 and October 2016. Using correlation analysis, we examined to what degree performance on the knowledge test, OSCE, and SimSurg related to case examiner recommendations and FtP outcomes, including the unique predictive power of these three assessments. The outcome measures were case examiner recommendations (i) not fit to practise; ii) fit to practise on a limited basis; or iii) fit to practise) as well as FtP outcomes (i) erased/removed from the register; ii) having restrictions/conditions; or iii) be in good standing). For the qualitative component, 45 GP assessors were asked to rate whether they assess the same competencies and which assessment provides better feedback about candidates. RESULTS: There was significant overlap between OSCEs and SimSurg, p < 0.001. SimSurg had additional predictive power in the presence of OSCEs and the knowledge test (p = 0.030) in distinguishing doctors from different FtP categories, while OSCEs did not (p = 0.080). Both the OSCEs (p = 0.004) and SimSurg (p < 0.001) had significant negative correlations with case examiner recommendations when accounting for the effects of the other two assessments. Inductive thematic analysis of the responses to the questionnaire showed that assessors perceived OSCEs to be better suited to target specific knowledge and skills. SimSurg was thought to produce a more global picture as the scenarios more accurately portray a patient consultation. CONCLUSION: While all three assessments are strong predictors of both case examiner recommendations and FtP outcomes, our findings suggest that the efficiency of GP ToCs can be improved by removing some of this overlapping content

ORAL DIURETIC ACTIVITY OF HOT WATER EXTRACT OF H-GRADE QUILLS OF CINNAMOMUM ZEYLANICUM BLUME IN RATS

Objective: Cinnamomum zeylanicum Blume is claimed in Sri Lankan traditional medicine as a diuretic. Diuretics that are in current use possess serious adverse effects. Thus, there is a need for discovering efficacious and safe diuretics possibly from natural sources. Hence, the study was carried out to scientifically evaluate the diuretic potential of Cinnamomum zeylanicum Blume in vivo.Methods: Wistar albino rats weighing 180-270 g of either sex were divided into five groups containing six subjects in each. All were starved for 18 h and hydrated subsequently with oral sodium chloride solution (0.9%). Group, I (control) received normal saline (15 ml per animal orally). Group II, III, and IV received different doses (1500, 2250, 3000 mg/kg) of freeze-dried hot water extract of Cinnamomum zeylanicum Blume orally. Group V; (standard) received furosemide (13 mg/kg). Rats were placed individually in metabolic cages. Cumulative urine outputs at hourly intervals for six hours, urinary Na+, K+, Cl-, HCO3-, specific gravity, pH and total dissolved solids were determined. Results: A strong dose-dependent diuretic activity with a rapid onset of action, rapid peak diuresis and short duration of action was observed compared to furosemide. The diuretic action was accompanied with a significant (p&lt;0.05) increase in urinary Na+, HCO3- and pH and decrease in urinary H+. Conclusion: The results indicated that hot water extract of Cinnamomum zeylanicum Blume possesses marked diuretic action compared to furosemide. This is mediated primarily via loop diuretic mechanism similar to furosemide and partly by carbonic anhydrase inhibitory action

-***-****-* Information Theoretic Conditions for Tracking in Leader-Follower Systems with Communication Constraints

Abstract: In this paper, we introduce a general framework for tracking in leader-follower systems under communication constraints, in which the leader and follower systems as well as the corresponding controllers are spatially distributed and connected over communication links. We provide necessary conditions on the channel data rate of each communication link for tracking of the leader-follower systems. By considering the forward and feedback channels as one cascade channel, we also provide a lower bound for the data rate of the cascade channel for the system to track a reference signal such that the tracking error has finite second moment. Examples and simulations are provided to demonstrate some of the results

Cognitive Anti-Jamming Satellite-To-Ground Communications on NASA's SCaN Testbed

Machine learning aided cognitive anti-jamming communications is designed, developed and demonstrated on a live satellite-to-ground link. A wideband autonomous cognitive radio (WACR) is designed and implemented as a hardware-in-the- loop (HITL) prototype. The cognitive engine (CE) of the WACR is implemented on a PC while the software-defined radio (SDR) platform utilized two different radios for spectrum sensing and actual communications. The cognitive engine performs spectrum knowledge acquisition over the complete spectrum range available for the SATCOM system operation and learns an anti-jamming communications protocol to avoid both intentional jammers and inadvertent interferers using reinforcement learning. When the current satellite-to-ground link is jammed, the cognitive engine of the ground receiver directs the satellite transmitter to switch to a new channel that is predicted to be jammer-free for the longest possible duration. The end-to-end, closed-loop system was tested on the NASA Space Communications and Navigation (SCaN) Testbed on the International Space Station (ISS). The experimental results demonstrated the feasibility of satellite-to-ground cognitive anti-jamming communications along with excellent anti-jamming capability of machine learning aided cognitive protocols against several different types of jammers