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An Energy-Efficient User-Centric Approach High-Capacity 5G Heterogeneous Cellular Networks
No full textToday's cellular networks (3G/4G) do not scale well in heterogeneous networks (HetNets) of multiple technologies that employ network-centric (NC) model. This destabilization is due to the need for coordination and management of multiple layers of the HetNets that the NC models cannot provide. User-centric (UC) approach is one of the key enablers of 5G wireless cellular networks for rapid recovering from network failures and ensuring certain communication capability for the users. In this paper, we present resource-aware energy-saving technique based on the UC model for LTE-A HetNets. We formulate an optimization problem for UC as a mixed linear integer programming (MILP) that minimizes the total power consumption (Energy Efficiency) while respecting the data rate per user and propose a low complexity iterative algorithm to user terminal (UE)-eNodeB association. In UC model, UE possessing terminal intelligence can establish the transmission and reception with different cells within the LTEA HetNet assuming the existence of coordination between the different cells in the network. The performance is evaluated in terms of energy saving in the uplink and downlink and the added capacity to the network (data rate). The evaluation is carried out by comparing a UC model against a NC model with the same simulation setup. The results show significant percentage of energy saving at eNodeBs and UEs in a UC model. Also, system capacity is enhanced in the UC model in both the uplink and downlink due to utilizing best channel gain for transmission and reception
Flexible Foundation Effect on Seismic Analysis of Roller Compacted Concrete (RCC) Dams Using Finite Element Method
No full textRecently, Roller Compacted Concrete (RCC) dams have become one of the most applicable types of dams across the globe. However, the basic challenge in analysis of RCC dams is evaluation of the actual response under earthquake excitations with considering flexible foundation and impounded water. For this purpose, a finite element model of RCC Dam-Reservoir-Foundation is accurately developed and dynamic time history analysis is utilized to assess the seismic responses in terms of acceleration, displacements, stresses, cracking patterns and crack propagation by implementation of concrete damaged plasticity model. A verification model is carried out to show the work accuracy. Based on these explanations, the obtained results showed that, however, the hydrodynamic pressure due to the reservoir water had great influence on seismic responses of the RCC dam with rigid foundation especially in terms of displacement response but overall responses of the dam are greatly fluctuated while flexible foundation is taken into consideration
Energy and exergy analysis of the PVT system: Effect of nanofluid flow rate
No full textSolar energy is one of the promising resources to fulfil the energy demands to some level in place of fossil fuels to avoid environmental pollution. The efficiency of solar technology, e.g. photovoltaic panels, thermal systems or a combination of both technologies as photovoltaic thermal is a concern to increase at an optimum level. A three-dimensional numerical analysis of PVT systems using water and MWCNT-water nanofluid has been completed with FEM based software COMSOL Multiphysics®. A numerical investigation has been validated by the indoor experimental research at different mass flow rates of 30 to 120 L/h while keeping solar irradiation fixed at 1000 W/m2, inlet fluid and ambient temperature at 32 and 25 °C, respectively. Percent improvement of electrical efficiency of PV with nanofluid cooling at flow rate 120 L/h is obtained about 10.72 and 12.25% of numerical and experimental cases respectively. Optimization of the nanofluid for weight concentration is achieved at 0.75% MWCNT-water. Solar cell temperature reduces about 0.72 °C experimentally and 0.77 °C numerically per 10 L/h flow rate increment. Approximately 7.74 and 6.89 W thermal energy is enhanced per 10 L/h flow rate increment in numerical and experimental studies respectively. Percentage increment of thermal efficiency is found as 5.62% numerically and 5.13% experimentally for PVT system operated by water/MWCNT nanofluid with compared to water
Knee cartilage segmentation and thickness computation from ultrasound images
No full textQuantitative thickness computation of knee cartilage in ultrasound images requires segmentation of a monotonous hypoechoic band between the soft tissue-cartilage interface and the cartilage-bone interface. Speckle noise and intensity bias captured in the ultrasound images often complicates the segmentation task. This paper presents knee cartilage segmentation using locally statistical level set method (LSLSM) and thickness computation using normal distance. Comparison on several level set methods in the attempt of segmenting the knee cartilage shows that LSLSM yields a more satisfactory result. When LSLSM was applied to 80 datasets, the qualitative segmentation assessment indicates a substantial agreement with Cohen’s κ coefficient of 0.73. The quantitative validation metrics of Dice similarity coefficient and Hausdorff distance have average values of 0.91 ± 0.01 and 6.21 ± 0.59 pixels, respectively. These satisfactory segmentation results are making the true thickness between two interfaces of the cartilage possible to be computed based on the segmented images. The measured cartilage thickness ranged from 1.35 to 2.42 mm with an average value of 1.97 ± 0.11 mm, reflecting the robustness of the segmentation algorithm to various cartilage thickness. These results indicate a potential application of the methods described for assessment of cartilage degeneration where changes in the cartilage thickness can be quantified over time by comparing the true thickness at a certain time interval
Impact of dietary solvents on flexural properties of bulk-fill composites
No full textObjective: This study investigated the effect of dietary solvents on flexural strength and modulus of bulk-fill composites. Materials and methods: One conventional composite (Filtek Z350 [FZ]), two bulk-fill composites (Filtek Bulk-fill [FB] and Tetric N Ceram [TN]) and a bulk-fill giomer (Beautifil-Bulk Restorative [BB]) were evaluated. Specimens (12 × 2 × 2 mm) were fabricated using customized stainless steel molds. Specimens were light-cured, removed from their molds, finished, measured and randomly divided into six groups. The groups (n = 10) were conditioned in the following mediums for 7 days at 37 °C: air (control), artificial saliva (SAGF), distilled water, 0.02 N citric acid, heptane, 50% ethanol–water solution. After conditioning, the specimens were rinsed, blotted dry, measured and subjected to flexural testing using a universal testing machine. Representative SEM images of the intact surfaces were obtained to appraise the degradation mechanism by dietary solvents. Data was subjected to statistical analysis using ANOVA/Tukey's tests at significance level p < 0.05. Results: Significant differences in flexural properties were observed between materials and conditioning mediums. The highest flexural properties were usually obtained with conditioning in air (control) or heptane. Exposure to aqueous solutions generally reduced flexural properties of bulk-fill composites. Conclusion: The effect of dietary solvents on flexural properties of bulk-fill composites was material and medium dependent
Bat algorithm for dam–reservoir operation
No full textOptimizing reservoir operation rule is considered as a complex engineering problem which requires an efficient algorithm to solve. During the past decade, several optimization algorithms have been applied to solve complex engineering problems, which water resource decision-makers can employ to optimize reservoir operation. This study investigates one of the new optimization algorithms, namely, Bat Algorithm (BA). The BA is incorporated with different rule curves, including first-, second-, and third-order rule curves. Two case studies, Aydoughmoush dam and Karoun 4 dam in Iran, are considered to evaluate the performance of the algorithm. The main purpose of the Aydoughmoush dam is to supply water for irrigation. Hence, the objective function for the optimization model is to minimize irrigation deficit. On the other hand, Karoun 4 dam is designed for hydropower generation. Three different evaluation indices, namely, reliability, resilience, and vulnerability were considered to examine the performance of the algorithm. Results showed that the bat algorithm with third-order rule curve converged to the minimum objective function for both case studies and achieved the highest values of reliability index and resiliency index and the lowest value of the vulnerability index. Hence, the bat algorithm with third-order rule curve can be considered as an appropriate optimization model for reservoir operation
Genetic differentiation of Anisakis species (Nematoda: Anisakidae) in marine fish Priacanthus tayenus from Gulf of Thailand
No full textMembers of the genus Anisakis are parasitic nematodes of the family Anisakidae. They are potential zoonotic parasites, causing anisakiasis in humans who consume raw or undercooked seafood (fish or squid) infected with the larvae of this nematode. In the present study, anisakid nematodes collected from the marine fish Priacanthus tayenus (Purple-spotted big-eye) caught from the Gulf of Thailand were examined morphologically and characterized genetically by DNA sequence analysis. Sequence data from the mitochondrial cytochrome c oxidase subunit II (mtDNA cox2) gene were used to identify these nematodes to species level and to evaluate the phylogenetic relationship among various taxa. All the 15 third-stage larvae of Anisakis nematodes investigated in this study belonged to the same genetic lineage as the A. typica species complex (named here as A. typica sp. T – T for Thailand). Eight mtDNA cox2 haplotypes were revealed in the 15 isolates of this Anisakis from Thailand. The mtDNA cox2 haplotypes of A. typica sp. T from Thailand were genetically distinct from those of the A. typica sensu stricto. Taxonomic description of this A. typica sp. T as a distinct species however awaits the availability of adult specimens
Mach–Zehnder interferometric magnetic field sensor based on a photonic crystal fiber and magnetic fluid
No full textA Mach–Zehnder interferometric magnetic field sensor based on a photonic crystal fiber (PCF) and magnetic fluid (MF) was designed and experimentally demonstrated. The sensing probe consists of a single-mode-(SM)multimode-PCF-SM fiber structure through arc fusion splicing. It was then laser engrave notched with the femtosecond laser so that the PCF cladding was selectively infilled MF. A well-defined interference pattern was obtained on account of the tunable refractive index of the MF infilled PCF cladding. The transmission spectra of the proposed sensor under different magnetic field intensities have been measured and theoretically analyzed. The results show that the sensitivity of the proposed sensor can reach −0.13 dB∕mT and 0.07334 nm/mT in the magnetic field intensity from 1 mT to 20 mT and 2 mT to 20 mT, respectively
Developmental Approach for Behavior Learning Using Primitive Motion Skills
No full textImitation learning through self-exploration is essential in developing sensorimotor skills. Most developmental theories emphasize that social interactions, especially understanding of observed actions, could be first achieved through imitation, yet the discussion on the origin of primitive imitative abilities is often neglected, referring instead to the possibility of its innateness. This paper presents a developmental model of imitation learning based on the hypothesis that humanoid robot acquires imitative abilities as induced by sensorimotor associative learning through self-exploration. In designing such learning system, several key issues will be addressed: Automatic segmentation of the observed actions into motion primitives using raw images acquired from the camera without requiring any kinematic model; incremental learning of spatiooral motion sequences to dynamically generates a topological structure in a self-stabilizing manner; organization of the learned data for easy and efficient retrieval using a dynamic associative memory; and utilizing segmented motion primitives to generate complex behavior by the combining these motion primitives. In our experiment, the self-posture is acquired through observing the image of its own body posture while performing the action in front of a mirror through body babbling. The complete architecture was evaluated by simulation and real robot experiments performed on DARwIn-OP humanoid robot
Bridging the gap between organisational practices and cyber security compliance: Can cooperation promote compliance in organisations?
No full textDrawing on public goods and institutional theory, this study examines the mediation effect of cooperation on the relationship between organisational practices, namely, top management commitment (TMC), structured security processes (SSP) and security investment (SI) and cyber security compliance in organisations. Using data from Malaysia’s critical sectors, ordinal regression was used to establish the odds of security compliance with security practices adjusted for job portfolio, security responsibility and educational levels. The results show that cooperation mediates TMC and SSP in achieving security compliance. The indirect effect of cooperation on these practices shows its subtle influence, which was not demonstrated in previous studies. These results also support the non-excludable characteristic of cyber security as a public good where cooperation overrides free-riding when security aspects are involved