On the Minimization of Handover Decision Instability in Wireless Local Area Networks

This paper addresses handover decision instability which impacts negatively on both user perception and network performances. To this aim, a new technique called The HandOver Decision STAbility Technique (HODSTAT) is proposed for horizontal handover in Wireless Local Area Networks (WLAN) based on IEEE 802.11standard. HODSTAT is based on a hysteresis margin analysis that, combined with a utilitybased function, evaluates the need for the handover and determines if the handover is needed or avoided. Indeed, if a Mobile Terminal (MT) only transiently hands over to a better network, the gain from using this new network may be diminished by the handover overhead and short usage duration. The approach that we adopt throughout this article aims at reducing the minimum handover occurrence that leads to the interruption of network connectivity (this is due to the nature of handover in WLAN which is a break before make which causes additional delay and packet loss). To this end, MT rather performs a handover only if the connectivity of the current network is threatened or if the performance of a neighboring network is really better comparing the current one with a hysteresis margin. This hysteresis should make a tradeoff between handover occurrence and the necessity to change the current network of attachment. Our extensive simulation results show that our proposed algorithm outperforms other decision stability approaches for handover decision algorithm.Comment: 13 Pages, IJWM

The effects of sr2w-1 supplementation on cycling performance and muscle fatigue

The purpose of this investigation was to examine the potential effects of SR2W-1 supplementation on cycling performance, central fatigue, and a variety of physiological parameters, including blood lactate, blood pH, heart rate (HR), rating of perceived exertion (RPE), oxygen consumption (VO2), expired ventilation (VE), and respiratory exchange ratio (RER). Methods: Five recreational cyclists (38 ± 8 yr, 168.4 ± 4.3 cm, 68.8 ± 5.6 kg, and 54.4 ± 2.6 mL/kg/min) performed 20-min of steady-state cycling (~85% VO2max) followed by three 1-min high intensity intervals at VO2max with 30-sec active recovery periods at 100 W, 15-min passive recovery period, and a ride to fatigue (or \u3c 50 RPM) at VO2max. Subjects were randomly assigned to receive either 1000mg/d of SR2W-1 (EXP) or 1000mg/d placebo (PLA). The supplement was distributed in a double-blind, crossover fashion. The twenty-one day supplementation periods were separated by a 14-day “washout” period. Change-scores from pre- to post- supplementation were calculated for all parameters, under both PLA and EXP conditions. Wilcoxon Signed-Rank Tests were utilized to compare change-scores between PLA and EXP conditions. Results: There were no differences between PLA and EXP for any of the dependent variables; however several variables approached significance (p \u3c 0.1). Specifically blood glucose levels, HR and ventilation increased to a greater extent with EXP, compared to PLA throughout the 20-min ride and high intensity intervals. Conclusion: Notwithstanding the small sample size, 3 weeks of herbal supplementation (SR2W-1) does not appear to aid in cycling performance, attenuate skeletal muscle fatigue, or modify the general physiological responses to exercise

On Myopic Sensing for Multi-Channel Opportunistic Access: Structure, Optimality, and Performance

We consider a multi-channel opportunistic communication system where the states of these channels evolve as independent and statistically identical Markov chains (the Gilbert-Elliot channel model). A user chooses one channel to sense and access in each slot and collects a reward determined by the state of the chosen channel. The problem is to design a sensing policy for channel selection to maximize the average reward, which can be formulated as a multi-arm restless bandit process. In this paper, we study the structure, optimality, and performance of the myopic sensing policy. We show that the myopic sensing policy has a simple robust structure that reduces channel selection to a round-robin procedure and obviates the need for knowing the channel transition probabilities. The optimality of this simple policy is established for the two-channel case and conjectured for the general case based on numerical results. The performance of the myopic sensing policy is analyzed, which, based on the optimality of myopic sensing, characterizes the maximum throughput of a multi-channel opportunistic communication system and its scaling behavior with respect to the number of channels. These results apply to cognitive radio networks, opportunistic transmission in fading environments, and resource-constrained jamming and anti-jamming.Comment: To appear in IEEE Transactions on Wireless Communications. This is a revised versio

Load Balancing Evaluation Tools for a Private Cloud: A Comparative Study

Cloud computing turns out to be an emerging technology that revolutionized the world of IT infrastructure. However, since the number of users is increasing daily, the demand for cloud services is increasing too. Thus, congestion occurs on the servers that provide services in the cloud. To avoid congestion, we used load balancer tools such as HAProxy and Nginx to intercept the requests of users and distribute them evenly to the servers. Jmeter is used to measure the performance metrics of least connection algorithm in terms of CPU utilization, response time, and concurrency level. Results showed high performance of HAProxy compared to Nginx in terms of response time and treating requests. Furthermore, we examined the characteristic of availability of the load balancer through deploying redundant load balancers, and we studied the effect of the failure of the load balancer on the quality of service of the end users. Keepalived is used to ensure a smooth transition between the two load balancers. According to the concurrency level, results proved that the number of unsuccessful requests during the failure of the master load balancer is proportionally minuscule compared to the total number of requests sent in a normal situation.

Dental crowding and its relationship to tooth size and arch dimensions

Background: Well alignments of the teeth in the dental arches achieves good esthetics  and  stability,  and a perfect  tooth  position  provides  ideal conditions  for  good  health  and  optimal  care of teeth. However, crowding of teeth is considered as the most common type of malocclusion. Aims: To quantify crowding by assessing the tooth size arch size discrepancy in crowded and non crowded arches. Materials and methods: The study was conducted on study casts obtained from sixty randomly selected students from College of Dentistry– University of Sulaimani in Kurdistan of Iraq with their age ranged from 19-24 years who were divided into crowded and noncrowded groups. For each group cumulative and individual tooth width and arch length were measured. They have been diagnosed and selected according to some specific criteria. Results: The study showed significant difference in the arch length measurement between the non crowded & crowded (P>0.01). No significant difference of the mesiodistal sums of entire arches between the non crowded and crowded samples (P>0.05) was observed while by individual measurements of tooth mesiodistal dimension highly significant difference were found only in the right lateral incisor (P=0.001) Conclusion: The arch length was the associated factors in contribution of dental crowding. Keywords: Dental crowding, malocclusion, arch dimensions

Forward Bay Cover Separation Modeling and Testing for the Orion Multi-Purpose Crew Vehicle

Spacecraft multibody separation events during atmospheric descent require complex testing and analysis to validate the flight separation dynamics model and to verify no recontact. NASA Orion MultiPurpose Crew Vehicle (MPCV) teams examined key model parameters and risk areas to develop a robust but affordable test campaign in order to validate and verify the Forward Bay Cover (FBC) separation event for Exploration Flight Test1 (EFT1). The FBC jettison simulation model is highly complex, consisting of dozens of parameters varied simultaneously, with numerous multiparameter interactions (coupling and feedback) among the various model elements, and encompassing distinct nearfield, midfield, and farfield regimes. The test campaign was composed of componentlevel testing (for example gaspiston thrusters and parachute mortars), ground FBC jettison tests, and FBC jettison airdrop tests that were accomplished by a highly multidisciplinary team. Three ground jettison tests isolated the testing of mechanisms and structures to anchor the simulation models excluding aerodynamic effects. Subsequently, two airdrop tests added aerodynamic and parachute parameters, and served as integrated system demonstrations, which had been preliminarily explored during the Orion Pad Abort1 (PA1) flight test in May 2010. Both ground and drop tests provided extensive data to validate analytical models and to verify the FBC jettison event for EFT1, but more testing is required to support human certification, for which NASA and Lockheed Martin are applying knowledge from Apollo and EFT1 testing and modeling to develop a robust but affordable human spacecraft capability

Penataan Kembali Kawasan Pasar Bunga Dan Pasar Hewan (Splendid) Kota Malang

Kota Malang memiliki pusat perbelanjaan bunga dan hewan (Splendid) yang berlokasi di Jl. Brawijaya dengan kontur tanah yang dibuat terasiring ke arah sungai. Lokasi pasar hewan dan pasar bunga yang berseberangan, namun tidak menjadi satu kesatuan membuat keduanya terkesan berjalan sendiri-sendiri. Padahal keduanya merupakan sebuah potensi wisata Kota Malang. Keberadaan elemen soft material dan hard material kurang optimal dalam penggunaannya. Penelitian ini dilakukan melalui survey lokasi untuk mendapatkan data berupa data fisik tapak, data klimatologi, dan data bio-fisik mengenai tapak. Sedangkan studi komparatif digunakan sebagai referensi terhadap perancangan lansekap nantinya. Penelitian mengenai kondisi eksisting lansekap ini didasarkan pada variabel analisa yang meliputi klimatologi, topografi, batas tapak, view, kebisingan, utilitas, bangunan, zonning, sirkulasi dan vegetasi. Dari hasil analisa tersebut diperoleh ragam data yang dijadikan dasar dalam konsep perancangan lansekap pasar bunga dan pasar hewan splendid Arsitektur Lansekap sebagai pendekatan perancangan Pasar Bunga dan Pasar Hewan diterapkan sebagai solusi dari permasalahan yang ada, dengan mewujudkan lingkungan binaan yang selaras dengan fungsi dan kondisi tapak. Rekonfigurasi karakter ruang Pasar Bunga dan Pasar Hewan, serta penataan ruang yang memprioritaskan ruang hijau untuk pendayagunaan elemen vegetasi sebagai pengkondisian pasif terhadap iklim mikro tapak dan kondisi eksisting tapak adalah garis besar konsep perancangan yang diterapkan pada Perancangan Kembali Kawasan Pasar Bunga dan Pasar Hewan (Splendid) Kota Malang

Resource Allocation for Real Time Services in LTE Networks: Resource Allocation Using Cooperative Game Theory and Virtual Token Mechanism

International audienceThe LTE specifications provide QoS for multimedia services with fast connectivity, high mobility and security. However, 3GPP specifications have not defined scheduling algorithms to exploit the LTE characteristics to support real time services. In this article we propose a two level scheduling scheme composed by cooperative game theory, a virtual token mechanism, and the well known algorithms EXP-RULE and Modified-Largest Weighted Delay Firs (M-LWDF) in downlink system. By using cooperative game theory such as bankruptcy game and Shapley value, the proposed mechanism works by forming coalitions between flow classes to distribute the bandwidth fairly among all of them. Both algorithms EXP-RULE and M-LWDF have been modified to use a virtual token mechanism to improve their performance, giving priority to real time flows. By taking the arrival rate of packets into account, the proposed mechanism partially included in previous schedulers has been adapted to this work to increase remarkably the performance of the resource allocation for real time flows. The performance evaluation is conducted in terms of system throughput, Packet loss ratio, total cell spectral efficiency, delay and fairness index

Fundamental movement skills and physical activity of 3–4-year-old children within early childhood centers in New Zealand

We sought to describe and explore relationships between fundamental movement skills (FMS) and level of physical activity (PA; light-, medium-, vigorous, and kCal/hour) in preschool children, aged 3–4-years-old, across four early childhood education (ECE) settings. Children’s FMS were assessed using the Test for Gross Motor Development-2 (TGMD-2; n = 81) and PA via accelerometers (S = 53). Eighty-four children participated, with 50 in both assessments. The TGMD-2 showed as the children got older, their locomotor skills (p < 0.001, r = 0.512) and object control motor skills (p < 0.001, r = 0.383) improved. Accelerometry showed children were primarily inactive at ECE (78.3% of the time). There were significant correlations between kCal/hour and light (p < 0.001, r = −0.688), moderate (p < 0.001, r = 0.599) and vigorous (p < 0.001, rs = 0.707) activity, and between gross motor quotient and locomotor (p < 0.001, r = 0.798) and object control (p < 0.001, r = 0.367) skills. No correlation was observed between gross motor quotient and kCal/hour. To conclude, children in this cohort were primarily inactive during ECE center hours. Moreover, gross motor quotient was significantly correlated to locomotor and object control skills. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Claire McLaughlin” is provided in this record*