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Search Results: 1 - 10 of 297935 matches for " Hani J. Kbashi "
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Nonlinear Dynamics in Directly Modulated Semiconductor Lasers with Optical Loop Mirror Feedback  [PDF]
Hani J. Kbashi
Optics and Photonics Journal (OPJ) , 2012, DOI: 10.4236/opj.2012.24032

The investigation of the nonlinear dynamics of a semiconductor laser based on nonlinear optical loop mirror (NOLM) feedback using Ge doped optical fiber was carried out experimentally. Animations of compilations of the output power as a function of time series and phase plane with effects of optical feedback level, carrier current and modulation signal strength are demonstrated as a tool to give insight into the laser dynamics. Different dynamic states, including 2×, 4× multiplication and quasi-periodic and periodic frequency-locked pulsing states extended to chaotic behaviour were observed by varying the parameters of modulated frequency and optical feedback strength. The frequency-locked pulsing states were observed to exhibit a harmonic frequency-locking phenomenon and the pulsing frequency is locked to a harmonic nonlinearity in loop instead of the modulated frequency.

Two Photon Absorption in Nanostructure Wide Band Gap Semiconductor CdS Using Femtosecond Laser  [PDF]
Abdulla M. Suhail, Raied K. Jamal, Hani J. Kbashi
Advances in Materials Physics and Chemistry (AMPC) , 2011, DOI: 10.4236/ampc.2011.13011
Abstract: Strong nonlinear absorption in CdS nanoparticles of dimensions in the range 4 - 50 nm when irradiated with a femtosecond pulsed laser at 800 nm is observed. The CdS nanoparticles sizes were controlled by changing the reaction time of aqueous solutions of thiourea and cadmium chloride. The structure of the prepared CdS nanoparticles were tested and their optical properties were investigated and the nonlinear absorption coeffi-cients were measured using a fully computerized z-scan unit. It is found that the formation of the CdS nanos-tructuresfor are responsible for the observation of the strong tow photon absorption.
Three-Photon Absorption in Nanostructure Wide-Band Gap Semiconductor ZnO Using Femtosecond Laser
Abdulla M. Suhail,Hani J. Kbashi,Raied K. Jamal
Modern Applied Science , 2011, DOI: 10.5539/mas.v5n6p199
Abstract: The three-photon absorption (3PA) in nanostructure wide-band gap ZnO semiconductor material is observed under high intensity femtosecond Titanium-Sapphire laser of 800 nm wavelength excitation. The ZnO nanofilms were prepared by chemical spray pyrolysis technique with substrate temperature of 370 oC. The optical properties concerning the absorption, transmission, and the photoluminescence spectra are studied for the prepared nanofilms. The structure of the ZnO nanofilm was tested with the X-Ray diffraction and it was found to be a polycrystalline with recognized peaks oriented in (002), (101), and (100). The measured nonlinear absorption coefficient was found to be about 0.062 cm3/Gwatt2, which is about ten time higher than the bulk value. The observation of 3PA under the influence of intense laser radiation was attributed to the two-photon absorption followed by free carrier absorption. The fully computerized z-scan system was used to measure the nonlinear coefficients from the Gaussian fit of the transmitted laser incident. The observation of the three-photon absorption under high intensity in nanocrystalline material attributed to the resonance between the 3hvsph and hvflu which is simply achieved in nanostructure.
Femtosecond Laser Amplification Based on Stimulated Raman Scattering in Optical Fibers
Hani Jassim Kbashi,Kais Al-Naimee,Hussein Jawad,Roberto Benocci
Applied Physics Research , 2010, DOI: 10.5539/apr.v2n2p55
Abstract: The amplification of femtosecond laser has been experimentally investigated around 1.060 mm wavelength through an optical fiber based on stimulated Raman scattering (SRS). A passively mode locked Nd:glass laser (model Timebandwidth GLX 200) giving a pulse duration of about 200 fsec at 1.060 mm wavelength and 120 mW average optical power with 100 MHz repetition rate is used as seed signal . Whereas the high repetition rate 88MHz Nd YLF laser operating at 1.053mm with pulse duration of 120 Psec is used as pump laser of the 15 and 25 m long single mode fiber. The broadening in the time of the pulse is done in the first few meters of the optical fiber and then amplified due to the energy transfer from pump laser source to the seed laser pulse. The results showed that the peak power conversion efficiency exceeds 45% and the on-off peak gain is about 2 dB. The peak wavelength shift is about 0.3 nm when the optical fiber is forward pumping by Nd-YLF laser. The self phase modulation (SPM) leads to compress the laser spectral width from 6.96 nm to 5 nm with small effect on the maximum nonlinear phase shift.
Privacy Level in Private Community Pharmacies in Saudi Arabia: A Simulated Client Survey  [PDF]
Hani M. J. Khojah
Pharmacology & Pharmacy (PP) , 2019, DOI: 10.4236/pp.2019.1010036
Abstract: Background: Maintaining privacy during patient counseling is critical, especially with respect to sensitive client issues. In general, community pharmacy practice in Saudi Arabia is considered substandard in several aspects, particularly with respect to the privacy it offers to pharmacy clients. However, to date, maintenance of privacy in Saudi Arabian community pharmacies has not been studied using a practical, measurable method. Objective: This study investigates the level and quality of privacy offered by community pharmacies in Madinah, Saudi Arabia. Methods: This study randomly selected 80 pharmacies, which were visited by a simulated client and a simulated customer who were instructed to engage in a standard scenario. During each pharmacy visit, the simulated client asked the on-duty pharmacist about the correct use of a medication intended for a vaginal disease. The simulated customer pretended to look for a nonmedical product on the shelf nearest to where the client-pharmacist consultation took place and observed whether the conversation was audible. Further, privacy facilities and pharmacist behaviors were documented. Results: A designated consultation area was found in only one pharmacy; however, it was not used and not designed as separate from the pharmacist’s counter. Although a designated waiting area was found in the same pharmacy, it was located too close for privacy to be maintained. Other physical measures of privacy were unavailable in all the other pharmacies. Regarding the simulated client-pharmacist consultation, the conversation was audible to the simulated customer in 63% of the pharmacies. Further, in most of the visited pharmacies, there was only one pharmacist on duty. Finally, a female pharmacist was found in only one pharmacy. Conclusions: The study concludes that a critical insufficiency in privacy exists in community pharmacies in Saudi Arabia. It reveals that most pharmacies must be infrastructurally redesigned to provide acceptable privacy levels. Further, the number of on-duty pharmacists should be increased, and pharmacies should employ more female pharmacists.
Do Community Pharmacies in Saudi Arabia Provide Medication-Related Information to Nonbuyers? A Mysterious Shopper Survey  [PDF]
Hani M. J. Khojah, Ahmed M. E. Abdalla
Pharmacology & Pharmacy (PP) , 2019, DOI: 10.4236/pp.2019.104015
Abstract: Background: Patient counseling service is an integral component of pharmacy practice in the community pharmacy. Counseling services should be provided to patients regardless of whether the patient has the intention to buy a medication or not. Objective: The aim of this study is to investigate the effect of the conflict between ethics and business objectives in Saudi Arabian private community pharmacies on patient counseling. Methods: Eighty pharmacies were randomly selected in Madinah, Saudi Arabia, and visited by mysterious shoppers following a preplanned scenario. Clients requested information on the correct use of a dry powder inhaler for bronchial asthma. A survey form was filled in by the clients immediately after the visit. Results: seventy-five pharmacies were included in the study. Seventy-seven percent of the pharmacists gave a varying content of information although the client showed no intention to buy the medication. Only 5% of pharmacists gave the full instructions regarding the correct handling of the device and using it for taking the correct dose. Around 68% of the pharmacists focused only on how to take the dose. Four percent of the pharmacists provided insufficient information. Around 23% of the pharmacists refused to give any information and referred the shopper to other sources for obtaining the required information. Conclusions: Although most of the pharmacists provided free counseling, the amount and level of information provided were generally insufficient. This illustrates the need for introducing clear policies and guidelines for providing free professional counseling services to patients in the community pharmacy setting in Saudi Arabia.
Dynamic Display of Changing Posterior in Bayesian Survival Analysis: The Software
Hani J. Doss,Balasubramanian Narasimhan
Journal of Statistical Software , 1999,
Evaluating Project Management Software Packages Using a Scoring Model—A Comparison between MS Project and Primavera  [PDF]
Hani Gharaibeh
Journal of Software Engineering and Applications (JSEA) , 2014, DOI: 10.4236/jsea.2014.77050

Since the Mid 1980’s, an increasing number of project management software packages (PMSP) has appeared in the market to support project management organizations. Despite the wide spread of PMSP, projects based organizations are left unguided as to how they should select the most appropriate software tool for their intended business use. The aim of this research was to apply a scoring model developed using ISO/IEC 14,000 software evaluation criteria to evaluate the effectiveness of two software packages in terms of functionality and price, and produce a summary of the evaluation records. To achieve research objective, a questionnaire survey method was used to investigate the two different project management software packages. One questionnaire was circulated among software users in various locations and another was targeting the software vendors. The findings of this study revealed differences between the two packages under investigation and highlighted the strength and weakness of each package. The author was able to assess the efficiency of each software package and provided a score for each attribute which helps the user to understand how the software package performs. This investigation revealed that the software user is not concerned with the most sophisticated package, or the package that has more advanced tools and features. What is more important for the user is their need to produce simple time charts, simple resource and cost analysis and basic reports.

Physical Layer Deterministic Network Coding Using PUM Turbo Codes over AWGN Channel, N Nodes through a Base Station Scenario  [PDF]
Hani Attar
Communications and Network (CN) , 2016, DOI: 10.4236/cn.2016.84022
Network Coding (NC) is a recent technique which is used to improve the transmission data rate and the power efficiency. These goals are obtained by combining data together before transmitting them, resulting to less transmitted data that carry the same amount of information. NC research work over the physical layer and the upper layers are popular and needed to be more investigated. In this paper, we propose a practical system of large-number of connected multi-source network coding (LMSNC), at the physical layer that exploits the broadcast nature of the wireless channel, using the practical and bandwidth-efficient schemes decode-and-forward (DF) and then compare it with Amplify and Forward (AF). The theoretical analysis and the simulation results show the effect of the noise when it cumulates in AF system and how DF is solving this severe default. Moreover, we consider the MSNC for Small-number of connected sources (SMSNC) and the two-way communication setup where two users exchange their information over an intermediate network node (ideally called Base Station), as two reference cases to compare with. With SMSNC, the number of necessary downlink transmissions from the intermediate node to the users is reduced, and thus the throughput is increased. Simulation results obtained using high-performance non-binary turbo codes, based on Partial Unit Memory (PUM) codes (4, 2, 1, 4) and (8, 4, 3, 8); confirm that combining PUM Turbo Code (PUMTC) and NC in the proposed MSNC setup gives almost the same BER performance as that for SMSNC at the small number of processing steps mainly when PUMTC (8, 4, 3, 8) is performed, which is required to retrieve the received coded messages. In the scenario of AF, combining packets results to cumulate the noise, which justifies the reason we decided to increase the number of transmitted coded messages in the network, i.e., the BER performance improves when sending extra coded messages. Finally, the possibility for a trade-off among BER, data rate and the number of transmitted coded messages is shown for LMSNC through graphics and simulation results.
Peak-to-Average Power Ratio Performance Analysis for Orthogonal Chirp Division Multiplexing Multicarrier Systems Based on Discrete Fractional Cosine Transform  [PDF]
Hani Attar
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2016, DOI: 10.4236/ijcns.2016.912043
Abstract: In doubly selective fading channels, the orthogonal frequency division multiplexing (OFDM) multicarrier system may fail. Chirp like basis (fractional Fourier transform-fractional cosine transform) may be used instead of complex exponential basis in this case to improve the system performance. However, in multicarrier transmission, the high peak to average power ratio (PAPR) of the transmitted signal is one of the difficult problems that face both the chirp and the exponential basis. In this paper, an evaluation for the PAPR performance of a multicarrier system based on the fractional cosine transform (FrCT) is introduced and then compared with DFrFT and FFT. Moreover, applying the SLAM technique over these systems is provided to understand the behaviour of these systems when applying SLAM. Simulations verify that this system obtains a better PAPR performance. Moreover, further PAPR reduction can be gained using the well-known PAPR reduction methods. Moreover, applying SLAM technique improves the performance of (dB) by 4 dB to 5 dB and all systems become as competitive to each other when SLAM is applied. Finally, BER performance comparison among OFDM, Discrete Cosine Transform MCM (DCT- MCM), Discrete Hartley Transform MCM (DHT-MCM), DFrFT-OCDM and DFrCT- OCDM MCM systems was done by means of simulation over 100,000 multicarrier blocks for each one and showed that our proposed scenario gave the best performance.
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