• International Journal of Computer Science & Network Security
• /
• v.21 no.11
• /
• pp.345-353
• /
• 2021

Cloud computing represent a new era of computing that's forms through the combination of service-oriented architecture (SOA), Internet and grid computing with virtualization technology. Virtualization is a concept through which every cloud is enable to provide on-demand services to the users. Most IT service provider adopt cloud based services for their users to meet the high demand of computation, as it is most flexible, reliable and scalable technology. Energy based performance tradeoff become the main challenge in cloud computing, as its acceptance and popularity increases day by day. Cloud data centers required a huge amount of power supply to the virtualization of servers for maintain on- demand high computing. High power demand increase the energy cost of service providers as well as it also harm the environment through the emission of CO₂. An optimization of cloud computing based on energy-performance tradeoff is required to obtain the balance between energy saving and QoS (quality of services) policies of cloud. A study about power usage of resources in cloud data centers based on workload assign to them, says that an idle server consume near about 50% of its peak utilization power [1]. Therefore, more number of underutilized servers in any cloud data center is responsible to reduce the energy performance tradeoff. To handle this issue, a lots of research proposed as energy efficient algorithms for minimize the consumption of energy and also maintain the SLA (service level agreement) at a satisfactory level. VM (virtual machine) consolidation is one such technique that ensured about the balance of energy based SLA. In the scope of this paper, we explore reinforcement with fuzzy logic (RFL) for VM consolidation to achieve energy based SLA. In this proposed RFL based active VM consolidation, the primary objective is to manage physical server (PS) nodes in order to avoid over-utilized and under-utilized, and to optimize the placement of VMs. A dynamic threshold (based on RFL) is proposed for over-utilized PS detection. For over-utilized PS, a VM selection policy based on fuzzy logic is proposed, which selects VM for migration to maintain the balance of SLA. Additionally, it incorporate VM placement policy through categorization of non-overutilized servers as- balanced, under-utilized and critical. CloudSim toolkit is used to simulate the proposed work on real-world work load traces of CoMon Project define by PlanetLab. Simulation results shows that the proposed policies is most energy efficient compared to others in terms of reduction in both electricity usage and SLA violation.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2005.05a
• /
• pp.137-137
• /
• 2005

• The Journal of Internal Korean Medicine
• /
• v.28 no.2
• /
• pp.250-261
• /
• 2007

Objectives : The purpose of this study was to evaluate the blood flow using doppler ultrasound of the MCA, ACA, PCA, BA, ICA in the patients with risk factor for stroke. Methods : 110 patients with risk factor for stroke were selected who had hypertension, diabetes mellitus, hyperlipidemia, or heart disease, as well as 89 healthy adults who did not have any symptoms of those diseases. To evaluate the blood flow, the Vs and Vm of the MCA, ACA, PCA, BA, and ICA in the two groups were measured. Result : In normal healthy adults, subjects showed a decrease in the Vs and Vm: with advancing in age, there was a significant difference in the Vs of MCA, PCA, BA, and ICA. There was a significant difference in the Vm of MCA, PCA, BA, and ICA. In normal healthy adults, females showed high velocities in all examined vessels. There was a significant difference in the Vs of BA. There was a significant difference in the Vm of BA, and ICA. There was a decrease in the Vs, and Vm of all examined vessels of patients with risk factors for stroke in comparison with normal healthy adults. There was no significant difference in the Vs. There was a significant difference in the Vm of MCA, ACA, and PCA. Results were the same between patients aged under 50 and total patients in the Vs and Vm of examined vessels. There were differences between patients aged over 50 and total patients in the Vs of MCA, PCA, BA and for patients aged over 50; patients with risk factor for stroke who had hypertension, diabetes mellitus, hyperlipidemia, or heat disease has higher Vs than healthy adults. Conclusions : There was a significant difference in the blood flow velocity between patients with risk factors for stroke and healthy adults. However, this result was different from results of comparison of TCD findings between patients and healthy individuals by age. Therefore, more detailed studies about aged patients are needed.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.23 no.6
• /
• pp.1513-1520
• /
• 2009

The purpose of this study was to compare cerebral blood flow between hyperlipidemic patient group and normal healthy aldult group using transcranial doppler ultrasonography(TCD). I investigated cerebral blood flow of 63 hyperlipidemic patients and 42 healthy adults. To evaluate the cerebral blood flow, I measured the systolic peak velocity(Vs) and mean flow velocity(Vm) of the milddle cerebral artery(MCA), anterior cerebral artery(ACA), posterior cerebral artery(PCA), basilar artery(BA), internal carotid artery(ICA) in the two groups using TCD. In normal healthy adults, subjects showed a decerease in Vs and Vm with advancing in age. There was a significant difference in the Vm of ICA. There was no significant differences in the Vm of ACA and ICA. In normal healthy adults, females showed high velocities of all examined vessel. There was a significant difference in the Vs of ICA. There was a significant differences in the Vm of MCA and ICA. Normal healthy adults higher than hyperlipidemic patients in the Vs of MCA, ACA, PCA. There was no significant difference in the Vs of all exmined vessels. Hyperlipidemic patientsincrease higher than normal healthy adults in the Vm of ACA. There was a significant difference in the Vs of BA. In the patients aged under 50's, normal healthy adults higher than hyperlipidemic patients in the Vs and Vm except BA. But there was no significant difference in all exmined vessels. In the patients aged over 50's, hyperlipidemic patients higher than normal healthy adults in all examined vessel expect PCA. There was a significant difference in the Vs of BA and ICA. And hyperlipidemic patients higher than that normal healthy adults in all exmined vessels. There was a significant difference in BA and ICA. In this study, visible differences in blood flow between hyperlipidemic patient group and normal healthy aldult group were shown. However, these results do not come up to the previous values that were reported and known worldwide.

• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.4
• /
• pp.544-547
• /
• 1999

The object of this study was to determine the influence of monensin and virginiamycin (VM) on in vitro ruminal fermentation of rice straw or ammoniated rice straw. Rumen fluid was collected from 4 wethers fed 200 g of concentrate supplement with 400 g of untreated (U) or ammoniated (A) rice straw once daily for 28 days. Mixed ruminal microorganisms were incubated in anaerobic media that contained 20% (vol/vol) ruminal fluid and 0.3 g of either U or A rice straw. Monensin and/or VM, dissolved in ethanol, were added in centrifuge tubes at final concentrations of 0, 15, 30, 15+15 and 30+30 ppm of culture fluid. The addition of monensin and VM combination to A rice straw fermentation decreased (p<0.05) the acetate to propionate ratio, total VFA and lactate production, but increased (p<0.05) pH. Total gas production tended to be decreased by the addition of monensin plus VM. Antimicrobial agents decreased $NH_3$ N concentration and dry matter digestibility.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.8
• /
• pp.3865-3883
• /
• 2016

Infrastructure as a Service (IaaS) encapsulates computer hardware into a large amount of virtual and manageable instances mainly in the form of virtual machine (VM), and provides rental service for users. Currently, VM anomaly incidents occasionally occur, which leads to performance issues and even downtime. This paper aims at detecting anomalous VMs based on performance metrics data of VMs. Due to the dynamic nature and increasing scale of IaaS, detecting anomalous VMs from voluminous correlated and non-Gaussian monitored performance data is a challenging task. This paper designs an anomaly detection framework to solve this challenge. First, it collects 53 performance metrics to reflect the running state of each VM. The collected performance metrics are testified not to follow the Gaussian distribution. Then, it employs independent components analysis (ICA) instead of principal component analysis (PCA) to extract independent components from collected non-Gaussian performance metric data. For anomaly detection, it employs multi-class Bayesian classification to determine the current state of each VM. To evaluate the performance of the designed detection framework, four types of anomalies are separately or jointly injected into randomly selected VMs in a campus-wide testbed. The experimental results show that ICA-based detection mechanism outperforms PCA-based and LDA-based detection mechanisms in terms of sensitivity and specificity.

• Physical Therapy Korea
• /
• v.4 no.2
• /
• pp.66-76
• /
• 1997

The purpose of this study was to compare the integrated electromyographic activity ratios of vastus lateralis(VL); rectus femoris lateral portion (RFL); rectus femoris medial portion(RFM); and vastus medialis(VM) muscles of 30 healthy subjects under three proprioceptive neuromuscular facilitation(PNF) techniques. Each subject was randomly assigned to one of 3 PNF techniques groups : slow reversal(SR), slow reversal hold(SRH) and rhythmic stabilization (RS). Each person was positioned in supine with the right hip flexed to $45^{\circ}$ and the knee fully extended and received a total of 6 sessions. Each technique was applied to the right lower extremity in two diagonal patterns while electrical activity was monitored from the ipsilateral muscles VL, RFL, RFM, and VM, respectively. Comparison of normalized mean EMG magnitudes from VL, VM showed that RS demonstrated significantly greater activity than that of SR or SRH and that RFL and RFM did not demonstrate any greater relative EMG activity with the three PNF techniques than did VL or VM.

• Journal of Korean Biological Nursing Science
• /
• v.11 no.1
• /
• pp.68-76
• /
• 2009

Purpose: The purpose of this study was to evaluate the hemodynamic changes in degree and duration that occur during Valsalva maneuver (VM). Furthermore, we wanted to investigate the patterns and mechanisms of physiological hemodynamic control. Method: Thirty six healthy college students were recruited from Y university. Each participant was provided with written informed consent. Blood pressure (BP), heart rate (HR), cardiac output (CO) were continuously recorded using the Finometer. Result: During the phase I of VM, means of systolic and diastolic pressures were increased by 32.15% and 38.28%, respectively, compared with basal values. HR and CO were decreased by 9.91% and 13.01%, respectively. Immediately after the maneuver (phase III), systolic and diastolic pressures were decreased by 5.05% and 6.24%, respectively, compared with those obtained in the phase II. HR and CO were elevated by 13.33% and 11.93%, respectively, compared to the levels of earlier phases. BPs were represented with overshoot in the phase IV, and recovered by baseline values about 20 sec after VM. Conclusion: These results demonstrated that hemodynamic changes are variable in the event of VM even in healthy humans. It will be valuable to accumulate more quantitative hemodynamic information in special populations such as the elderly and the patients with cardiovascular problems.

• Journal of Korean Institute of Industrial Engineers
• /
• v.38 no.1
• /
• pp.46-56
• /
• 2012

The purpose of virtual metrology (VM) in semiconductor manufacturing is to predict every wafer's metrological values based on its process equipment data without an actual metrology. In this paper, we propose novelty detection-based reliability estimation models for VM in order to support flexible utilization of VM results. Because the proposed model can not only estimate the reliability of VM, but also identify suspicious process variables lowering the reliability, quality control actions can be taken selectively based on the reliance level and its causes. Based on the preliminary experimental results with actual semiconductor manufacturing process data, our models can successfully give a high reliance level to the wafers with small prediction errors and a low reliance level to the wafers with large prediction errors. In addition, our proposed model can give more detailed information by identifying the critical process variables and their relative impacts on the low reliability.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.9 no.2
• /
• pp.7-12
• /
• 2011

Purpose : We studied the correlation between reference voluntary contraction (% RVC) of vastus lateralis (VL) and vastus medialis (VM), Berg balance scale (BBS), and timed-up & go (TUG) test. Methods : We recruited 30 stroke patients from a rehabilitation center at a hospital.? All subjects could walk with or without an assisting device. Subjects were evaluated with % RVC of VL and VM, BBS, and TUG. The data were analyzed using a Pearson correlation coefficient. Results : The % RVC of VL and VM and BBS (p<0.01) showed a significant positive correlation. TUG negatively correlated with % RVC of VL and VM and BBS (p<0.01). Conclusion : Lower extremity muscle activity increases balance and walking ability. We recommend the implementation of lower extremity strength exercises in the rehabilitation of stroke patient.