A robust video-bitrate adaptive scheme at client-aspect plays a significant role in keeping a good quality of video streaming technology experience. Video quality affects the amount of time the video has turned off playing due to the unfilled buffer state. Therefore to maintain a video streaming continuously with smooth bandwidth fluctuation, a video buffer structure based on adapting the video bitrate is considered in this work. Initially, the video buffer structure is formulated as an optimal control-theoretic problem that combines both video bitrate and video buffer feedback signals. While protecting the video buffer occupancy from exceeding the limited operating level can provide continuous video streaming, it may also cause a video bitrate oscillation. So the video buffer structure is adjusted by adding two thresholds as operating points for overflow and underflow states to filter the impact of throughput fluctuation on video buffer occupancy level. Then a bandwidth prediction algorithm is proposed for enhancing the performance of video bitrate adaptation. This algorithm's work depends on the current video buffer level, video bitrate of the previous segment, and iterative throughput measurements to predict the best video bitrate for the next segment. Simulation results show that reserving a bandwidth margin is better in adapting the video bitrate under bandwidth variation and then reducing the risk of video playback freezing. Simulation results proved that the playback freezing happens two times: firstly, when there is no bandwidth margin used and secondly, when the bandwidth margin is high while smooth video bitrate is obtained with moderate value. The proposed scheme is compared with other two schemes such as smoothed throughput rate (STR) and Buffer Based Rate (BBR) in terms of prediction error, QoE preferences, buffer size, and startup delay time, then the proposed scheme outperforms these schemes in attaining smooth video bitrates and continuous video playback.
The research topic was chosen because of the importance of communication in organizations in general and the marketing process in particular. Without communication, the organization can not live and continue ,The problem of study diagnosis the reduction in sales in the company of plant oils in some its classes and weakness in differentiation and its reputation at market in spit if having good products with standardized features And lack of customer communication channels, also the company does not have any whole view about the concept of marketing communication, Therefore, This sudy aimed ro define to know the type of relationship between the extent of the impact of the integrated marketing
... Show MoreBeta-irradiation effects on the microstructure of LDPE samples have been investigated
using Positron Annihilation Lifetime Technique (PALT). These effects on the orthopositronium
(o-Ps) Lifetime t3, the free positron annihilation lifetime 2 t , the free-volume
hole size (Vh) and the free volume fraction (fh) were measured as functions of Beta
irradiation - dose up to a total dose of 30.28 kGy.
The results show that the values of t3, Vh and fh increase gradually with increasing Beta
dose up to a total dose of 1.289 kGy, and reach a maximum increment of 17.4%, 32.8% and
5.86%, respectively, while t2 reachs maximum increment of 211.9% at a total dose of 1.59
kGy. Above these doses, the values show nonlinear changes u
Incident laser power and concentration effects on fluorescence emission from DCM dye in PMMA polymer have been investigated. Different concentrations of the dye were used. It was found that the fluorescence intensity increased with increasing of the concentration of the dye, with a red shift. In addition, it was found that the fluorescence intensity increased with the increase of the incident laser power I0.
Background: The aim of the study was to evaluate the amount of changes in the horizontal and vertical maxillary arch dimensions measurements following the premature loss of primary molars. Materials and methods: The sample consist of (50) children with unilateral prematurely extracted either first or second primary molars at the mixed dentition stage. Results and Conclusions: Results shows that there was an increase in the vertical incisor to canine distance (A) with both premature loss of first & second primary molars due to distal movement of primary canines and at the same time there were a significant loss of space in the extraction space with premature loss of second primary molar due to a mesial movement of maxillary first permanent
... Show MoreCadmium sulphide CdS films with 200 nm have been prepared by thermal evaporation technique on glass substrate at substrate room temperature under vacuum of 10-5mbar.In this paper, the effect of Dielectric Barrier Discharge plasma on the optical properties of the CdS film. The prepared films were exposed to different time intervals (0, 3, 5, 8) min. For every sample, the Absorption A, absorption coefficient α , energy gap Eg ,extinction coefficient K and dielectric constant ε were studied. It is found that the energy gap were decreased with exposure time, and absorption , Absorption coefficient, refractive index, extinction coefficient, dielectric constant increased with time of exposure to the plasma. Our study conside
... Show MoreABSTRACT Background: According to Branemark’s protocol, the waiting period between tooth extraction and implant placement is 6–8 months; this is the late placement technique. Achieving and maintaining implant stability are prerequisites for a dental implant to be successful. Resonance Frequency Analysis (RFA) is a noninvasive diagnostic method that measures implant stability. The aim of this study was to investigate the influence of treatment protocol and implant dimensions on primary implant stability utilizing RFA. Materials and methods: This study included 63 Iraqi patients (37 male, 26 female; ranging 22-66 years). According to treatment protocol, the sample was divided into 2 groups; A (delayed) & B (immediate). Dental im
... Show MoreAntibacterial activity of CNSs against Staphylococcus aureus and Escherichia coli was estimated. Higher inhibition zone of 18 mm and 20 mm were observed against S. aureus and E.coli, respectively, at a concentration of 2 mg/ml of carbon nanosphere after 24 hrs of incubation at 37 ºC. In vitro cytotoxicity experiment was performed on two parasite strains of Leishmania donovani and Leishmania tropica by using MTT assay. L. donovani revealed more sensitiv to the CNSs than L. tropica. An intermediate level of cytotoxicity of 51.31 % was observed when 2.4 mg/ml of CNSs was incubated with L. donovani, while weak cytotoxicity of 37.20 % was shown when the
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