Miracle-dz/UniFAR-FTUs huggingface dataset:
Scalable and Adaptive Data Replica Placement for Geo-Distributed Cloud Storages

In geo-distributed cloud storage systems, data replication has been widely used to serve the ever more users around the world for high data reliability and availability. How to optimize the data replica placement has become one of the fundamental problems to reduce the inter-node traffic and the system overhead of accessing associated data items. In the big data era, traditional solutions may face the challenges of long running time and large overheads to handle the increasing scale of data items with time-varying user requests. Therefore, novel offline community discovery and online community adjustment schemes are proposed to solve the replica placement problem in a scalable and adaptive way. The offline scheme can find a replica placement solution based on the average read/write rates for a certain period of time. The scalability can be achieved as 1) the computation complexity is linear to the amount of data items and 2) the data-node communities can evolve in parallel for a distributed replica placement. Furthermore, the online scheme is adaptive to handle the bursty data requests, without the need to completely override the existing replica placement. Driven by real-world data traces, extensive performance evaluations demonstrate the effectiveness of our design to handle large-scale datasets.
Wireless Backhaul: Intrinsic Bottleneck of Ultra-Dense Networks?

With the growing deployment of small cell base stations (BSs), the impact of backhaul congestion on the performance of small cell networks becomes dominant. To capture this effect, we present a conjoint framework integrating backhaul architecture with the access network. In particular, we evaluate the performance of ultra-dense networks (UDNs) in terms of network spatial throughput (ST), supposing that backhaul is conveyed to BSs through millimeter wave (mmWave) links by gateways. Notably, in contrast to diminishing to zero in previous work, network ST is shown to converge into a saturation under the given gateway density since the limited backhaul capability of gateways would stabilize the interference distribution of access network. Moreover, despite the benefit of enhancing backhaul capacity, over-deployed gateways would result in the potential intercell interference, which degrades network ST of UDN. On this account, we further study the optimization of gateway density to balance the tradeoff between enhancing backhaul capacity and mitigating intercell interference. It indicates that the application of mmWave beamforming at gateways leads to an increase in optimal gateway density, under which network ST could be further improved.
Closed-Form Beamforming Aided Joint Optimization for Spectrum- and Energy-Efficient UAV-BS Networks

In this paper, we investigate a spectrum- and energy-efficient emergency wireless communication system with an unmanned aerial vehicle (UAV) mounted base station (BS). To the best of our knowledge, this is the first work to investigate joint optimization of three-dimensional (3D) beamforming (BF), power allocation (PA), user scheduling and UAV trajectory, to maximize the average spectrum efficiency (SE) while maintaining high energy efficiency (EE). Furthermore, a closed- form BF design in both angle- and power-domains is proposed for the first time for UAV-BS assisted wireless systems. Thanks to the closed-form solutions, a low-complexity iterative algorithm is proposed for joint optimization, which converges within only one or two iterations. Simulation results show that 3D BF plays a dominant role in the overall performance, and the proposed closed- form 3D BF design achieves near-optimal performance in terms of both EE and SE, while requiring much lower complexity than exhaustive search. The maximum UAV speed with respect to the optimal EE is also obtained.
TAXPAYERS' ATTITUDES AND TAX COMPLIANCE BEHAVIOUR IN KENYA How the Taxpayers' Attitudes Influence Compliance Behavior among SMEs Business Income Earners in Kerugoya Town, Kirinyaga District

The major purposes of this study were to document the taxpayers’ attitudes and tax compliance behaviour in Kenya, the case of SMEs business income earners in Kerugoya town, Kirinyaga district. and also to identify taxpayers’ attitudes towards tax systems, to identify factors which influence taxpayers’ attitudes and to establish relationship between attitudes and tax compliance behaviour among SMEs business income earners in Kerugoya town, Kirinyaga district. This research was a survey involving business income earners among small and medium size enterprises in Kerugoya town, in Kirinyaga district. Data was collected from two hundred and sixty (260) small and medium size enterprises taxpayers, analyzed using descriptive statistics, and summarized and presented in the form of proportions, tables and percentages. The following conclusions were also arrived at: First, most taxpayers view the Kenyan tax system as unfair. This was because most respondents differed that they are paying a fair share of tax; that their neighbours, friends etc are reporting and paying tax honestly; that tax laws are easy to understand i.e. calculation of tax filing and paying dates. They were also indifferent with the paying of tax fines and penalties: the aggressive tax enforcement efforts by KRA e.g. ensuring tax audits and prosecutions of tax evaders take place. Secondly, most taxpayers have complied with the possession of PINs; the taxpayers in the district have partially complied in terms of keeping up to date records and books of accounts. This is because most of them keep Cash receipts, Cashbook, Balance sheet, Invoices, and Profit and Loss accounts. But other records like the trial balance; Journals and Ledgers are not up to date. Thirdly, the taxpayer file tax returns on or before 30th June, a sign that they actually comply with the dead lines given by KRA, which they file themselves instead of doing it using the Accountant/ tax advisor. Fourthly, most taxpayers in the district have never paid penalties. Fifthly, some of the factors for tax non-compliance were found to be: the inability to understand tax laws , a feeling that they are not paying a fair share of tax, positive peer attitude and Rewarding. Lastly, testing the hypothesis of the study that “Taxpayers’ attitudes do not encourage tax compliance in Kenya”, it was found that there is a very strong relationship between the taxpayers’ attitudes and tax compliance in Kenya i.e. taxpayers’ attitudes encourages tax compliance in Kenya since the correlation of 0.846 ≅1.
Physical Activity Sensing via Stand-Alone WiFi Device

WiFi signals for physical activity sensing show great practical potentials for pervasive healthcare applications due to the widespread WiFi deployments and high levels of public acceptance of such systems. Traditionally, WiFi-based sensing uses the Channel State Information (CSI) from an off-the-shelf WiFi Access Point (AP) which transmits signals that have high pulse repetition frequencies. However, when there are no users on the local network only beacon signals are transmitted from the WiFi AP which significantly deteriorates the sensitivity and specificity of such systems. Surprisingly, WiFi based sensing under these conditions have received little attention given that WiFi APs are frequently in idle state. This paper presents a practical system based on passive radar techniques which does not require any special setup or firmware changes to be able to work with any commercial WiFi device. To cope with the low duty cycles associated with beacon signal transmissions, a modified Cross Ambiguity Function (CAF) has been proposed to reduce redundant samples. In addition, an external device has been developed to send WiFi probe request signals which stimulates an idle AP to transmit WiFi probe responses, thus generate usable transmission signals for sensing applications without the need to authenticate and join the network. Detection performance shows that the proposed concept can significantly improve activity detection and is a viable candidate in future healthcare applications.
Fast Off-Grid Channel Estimation for Millimeter Wave Cellular Systems: A Flexible Convex Relaxation Method

In this paper, a novel off-grid channel model is considered for millimeter-wave (mmWave) cellular systems, where both the BS and MS employ large antenna arrays for directional beamforming. Accurate acquisition of channel knowledge for sufficient beamforming gain is challenging due to the large number of antennas and low coherence time. Different from most existing studies that are concerned with compressed sensing (CS)-based channel estimators, a novel convex formulation without semidefinite programming (SDP) relaxation is proposed for the off-grid/super-resolution channel estimation and then a low complexity solver based on alternating direction method of multipliers (ADMM) is developed. The simulation results demonstrate that the proposed off-grid method has better estimation accuracy and lower computational complexity compared with other state- of-the-art algorithms.
How Does Bribery Affect Public Service Delivery? Micro-Evidence from Service Users and Public Officials in Peru

When seeking a public service, users may be required to pay in bribes more than the official price. Consequently, some users may be discouraged and choose not to seek a service due to the higher price imposed by the bribery"tax. "This paper explores the price and quantity components of the relationship between governance and service delivery using micro-level survey data. The authors construct new measures of governance using data from users of public services from 13 government agencies in Peru. For some basic services, low-income users pay a larger share of their income than wealthier ones do; that is, the bribery tax is regressive. Where there are substitute private providers, low-income users appear to be discouraged more often and not to seek basic services. Thus, bribery may penalize poorer users twice - acting as a regressive tax and discouraging access to basic services. The paper explores the characteristics of households seeking public services. Higher education and age are associated with higher probability of being discouraged. Trust in state institutions decreases the probability of being discouraged, while knowledge of mechanisms to report corruption and extent of social network increase it, suggesting that households may rely on substitutes through networks. The study complements the household analysis with supply-side analysis based on data from public officials, and constructs agency-level measures for access to public services and institutional factors. Econometric results suggest that corruption reduces the supply of services, while voice mechanisms and clarity of the public agency's mission increase it.
A Semi-Automatic Optimization Design Method for SvcV-5 in DoDAF 2.0 Based on Service Identification

As one of the products in the US Department of Defense Architecture Framework version 2.0 (DoDAF 2.0), the Operational Activity to Services Traceability Matrix product (SvcV-5) links the operational viewpoint (OV) and service viewpoint (SvcV). SvcV-5 is an essential product for optimizing the design of other service view products; thus, it is necessary to study how to optimize the design of SvcV-5. This paper studies the semi-automatic design method of SvcV-5 based on the service identification method. The main idea of this paper is to extract relevant information from previous architecture design products, such as OV-6b, CV-4 and CV-6, and then to study the method of taking service identification and designing the SvcV-5 product. First, a message-based service initial identification method is used to generate the initial service set. Second, considering the measure of the cohesion and the coupling degree of the service, a service improving algorithm is used to update the initial service set. In this process, a dependency matrix between operational activities is established; this matrix includes data dependencies and capability requirement dependencies. Then, according to the mapping result of the service identification method, service-related information can be determined manually by designers. Finally, SvcV-5 can be generated through an automatic algorithm based on the service identification result and the OV-6b product. This article verifies the proposed method using the motivation example of the earthquake rescue information system (ERIS) architecture product design. Through conducting experimental analysis and comparing our method with other service identification methods, we illustrate the effectiveness of the proposed SvcV-5 optimization design method.
Effects of Ramadan Fasting on Ambulatory Blood Pressure in Hypertensive Patients

A R T I C L E I N F O A B S T R A C T Article type: Original article Introduction: Previous studies have indicated that Ramadan fasting has beneficial effects on cardiovascular risk factors, specially blood pressure and heart rate (1). In the present study, the effect of Ramadan fasting on 24-hour ambulatory blood pressure and heart rate has been investigated. Method: This prospective observational study was conducted on two groups of individuals. Six patients under hypertension treatment were allocated to the case group and 12 healthy individuals were selected as the control group. Twenty-four-hour blood pressure monitoring was carried out during four periods: prior to Ramadan, during the first ten days and the last ten days of Ramadan, and one month after it. All patients continued their medication, which was administered twice per day. Twenty-four-hour mean blood pressure, weight, body mass index (BMI), and waist circumference were compared among the groups. Results: In the case group, there was a significant reduction in subjects' weight during the third period of the experiment; also, a significant improvement was observed in the heart rate during the second and third periods in the case group (P<0.05, t-test). Conclusion: This study indicated a significant improvement in the subjects' heart rate over second and third periods of measurements; also, no high-risk variations in blood pressure or heart rate were observed among the subjects.
Design and Optimization of VCSELs for up to 40-Gb/s Error-Free Transmission Through Impurity-Induced Disordering

This article describes an optimized design and process for the improvement of the electrical properties of vertical-cavity surface-emitting lasers (VCSELs) via the impurity-induced disordering (IID) technology. Through the IID process, the electrical current path can be tailored to detour around the defect centers introduced by the oxidation process, resulting in a noticeable improvement in the dc and the RF characteristics of the IID VCSEL. The threshold current was reduced from 0.341 to 0.225 mA due to better current injection efficiency in the IID VCSEL. The characteristic temperature of the IID VCSEL increased from 106 to 150 K, and the slope of the <inline-formula> <tex-math notation="LaTeX">${I}$ </tex-math></inline-formula>–<inline-formula> <tex-math notation="LaTeX">${V}$ </tex-math></inline-formula> characteristics under low-level-injection regime could be improved to a factor of exp(<inline-formula> <tex-math notation="LaTeX">$qV/1.2 kT$ </tex-math></inline-formula>). The RF characteristics also echoed the dc characteristics, which the optical bandwidth of the IID VCSEL enhanced from 18.95 to 23.49 GHz, and showed a prominent difference on the <inline-formula> <tex-math notation="LaTeX">${K}$ </tex-math></inline-formula> factor (~0.26 to ~0.22 ns) and the D factor (~7 to ~11 GHz/(mA)<sup>1/2</sup>). The IID VCSEL is then employed for a data transmission link, an eye diagram was characterized at up to 44 Gb/s and passed 40-Gb/s error-free testing under on–off-keying (OOK) modulation.
Joint User Pairing and Power Control for C-NOMA with Full-Duplex Device-to-Device Relaying

This paper investigates the performance of coop- erative non-orthogonal multiple access (C-NOMA) in cellulardownlink systems. The system model consists of a base station(BS) that needs to serve multiple users within a region of service.A subset of the users, especially those located close to thecell edge, undergo severe fading and suffer from poor channelquality and low achievable rates. To overcome this problem, C-NOMA is proposed as the system design methodology, in whichusers that have the capability of full-duplex (FD) communicationcan assist the transmissions between the BS and users withpoor channel quality through device-to-device (D2D) communi-cations. To harness both the multiplexing gain from NOMA andthe diversity gain from FD-D2D communications, we formulateand solve a novel optimization problem that jointly deter-mines D2D user pairing and power allocation. The formulatedproblem is a mixed-integer non-linear program (MINLP) withprohibitively high complexity. To overcome this issue, a two-steppolicy is proposed to solve the problem in polynomial time. Oursimulation results show that with reasonable assumptions, theproposed scheme always outperforms some existing schemesin the literature, and that, under undesirable conditions, e.g.,poor D2D channel conditions or imperfect self-interference (SI)cancellation, the proposed scheme is reduced to conventionalNOMA.
AC Loss Characterization of HTS Pancake and Solenoid Coils Carrying Nonsinusoidal Currents

Application of high-temperature superconducting devices become promising in power networks, and transportation, including ship, train, and electric aircraft propulsion systems, with the advantages of light weight, compact size, and high efficiency, compared to conventional devices. In reality, electric networks—either in grid or transportation propulsion system—are polluted with harmonics due to the widespread use of power electronic devices and nonlinear loads. It is essential to explore the dependency of harmonic ac losses of different coil configurations carrying nonsinusoidal current. We modeled and compared harmonic ac loss behaviors in three coil configurations, single pancake coil (SPC), double pancake coil (DPC), and solenoid coil (SNC), where SPC and SNC are wound by identical wire length and DPC has twice conductor number compared to SPC. The research work has been carried out by means of H-formulation finite element method in a 2-D axisymmetric modeling environment of COMSOL Multiphysics. We explored and reported ac losses in these three coil structures carrying nonsinusoidal current with the third and the fifth harmonic orders, respectively, under different total harmonic distortion (THD) and fundamental current levels. It has been concluded that ac loss in these coils first decreases with the increase of the third harmonic content, when THD of the third harmonic <0.2; and increase with the increase of the third harmonic when THD >0.2. AC loss in coils monotonically increases with the increase of the fifth harmonic, drastically. We found that ac loss in SPC carrying the third harmonic and the fifth harmonic at different THD are more than 3.8 times of that in DPC; ac loss in SPC carrying either third or fifth harmonics at different THD are around 4.5 times of that in SNC.
Impact of Application Development in Managerial Skills, Knowledge and Enterprise Architecture amongst SMEs in Western Cape

The introduction of technology to South African SMEs has proved to enhance the effectiveness of South African SME industries while enabling competitive advantage. It is therefore evident, after a rigorous process of synthesizing the literature, that there is a gap in the literature that covers this topic. The literature fails to cover the managerial skills and orientation that would be required from stakeholders to manage and run the SMEs through the process of applications development in the SMEs. The study objective was to conduct an in-depth analysis of application development done in South African SMEs for business enablement towards competitive advantage. The study used a quantitative approach with the aim of providing an accurate representation of a large population based on a representative sample. The results suggest that SMEs can learn to implement methodologies and frameworks that introduce building applications based on scalability and reusability requirements. The study contributes to the body of knowledge and practice on application development in the SMEs sector.
An oneM2M Interworking Proxy Entity for ECHONET Lite Protocol

ECHONET Lite, a leading protocol in Japan smart homes, is getting more attention, especially in European countries. However, it lacks interoperability with service platforms and the support of standard APIs for service developers as well. This paper introduces a solution to handle ECHONET Lite device resources and transform these resources into standard APIs usable by third-party applications. To validate the feasibility of the proposed solution, An oneM2M Interworking Proxy Entity for ECHONET Lite protocol was implemented and ECHONET Lite devices are able to have interacted with devices from different domains via the oneM2M ecosystem.
TFET and FinFET Hybrid Technologies for SRAM Cell: Performance Improvement over a Large VDD-Range

This work proposes and compares Static Random-Access Memory (SRAM) cells using hybrid technology for enabling a large range of voltage operation. Tunnel FET (TFET), FinFET, and conventional MOSFET (CMOS) technologies are considered to build different hybrid SRAM cells: TFET/CMOS, FinFET /CMOS and FinFET/TFET. In all cases, only CMOS and FinFET are used as cross-coupled inverters. For our study, four SRAM topologies (6T, 8T, 9T, 10T) were considered and the simulation was carried out for voltage range from 0.4V to 0.8V. The determination of the Writing and Reading Margin, the Delay and the Power Consumption of each device, enable us to determine that the best trade-off for hybrid is the FinFET/TFET SRAM.
Non-Orthogonal Multiple Access in Air-to-Everything (A2X) Networks

This paper investigates the non-orthogonal multiple access (NOMA) enhanced Air-to-Everything (A2X) frameworks. A novel 3-Dimension unmanned aerial vehicles (UAVs) framework for providing wireless services to randomly roaming NOMA receivers (Rxs) in the sphere space is proposed by utilizing stochastic geometry tools. In an effort to evaluate the performance of the proposed framework, we first derive closed-form expressions for the outage probability of paired NOMA Rxs. For obtaining more insights, we investigate the diversity order of NOMA enhanced A2X frameworks. Our analytical results demonstrate that the diversity order and the high SNR slope of the proposed framework are m. Numerical results are provided to confirm that for the case of fixed LoS probability, the outage performance of paired NOMA Rxs mainly depends on users with poor channel conditions.
Online Trajectory and Radio Resource Optimization of Cache-Enabled UAV Wireless Networks With Content and Energy Recharging

Recently, unmanned aerial vehicle (UAV)-assisted wireless communication technology has been proposed to exploit the favorable propagation property and flexibility of air-to-ground channels to support content-centric caching and enhance wireless network capacity. In this article, we propose an online UAV-assisted wireless caching design via jointly optimizing UAV trajectory, transmission power and caching content scheduling. Specifically, we formulate the joint optimization of online UAV trajectory and caching content delivery as an infinite-horizon ergodic Markov Decision Process (MDP) problem to obtain a QoE-optimal solution based on the concept of request queues in wireless caching networks. By exploiting the fluid approximation approach, we first derive an optimal control policy from an approximated Bellman equation. Based on this, an actor-critic based online reinforcement learning algorithm is proposed to solve the problem. Finally, simulation results are provided to show that the proposed solution can achieve significant gain over the existing baselines.