22 research outputs found
Performance assessment of VoIP service over different handover mechanisms in UMTS networks
Many researchers have discussed various topics in universal mobile telecommunication system (UMTS) networks: the process of switching from one cell to another for the subscriber and the impact of the quality of the connection during the transition process, quality of services (QoS), the quality of the uplink and downlink carrier line, the various types of code for the voice transmitted through the Internet, especially the research that discussed voice over internet protocol (VoIP) technology as voice travels from cell to cell in mobile networks, depending on the type of delivery. In this paper, a proposed scenario of a UMTS network was implemented to evaluate the multicellular VoIP movement; the proposed UMTS network was simulated using the OPNET 14.5 simulator. The calculation and analysis of the different parameters of the user while moving from one cell to another with different movement speeds considered, the best mean opinion score (MOS) value (3.19) registered for the scenario (soft handover) comparing with another type of handover (3.00)
Marketing The Non-Profit Organizations,"The Jordan Museum as a case study"
The aim of this paper is to analyse the existing concepts of marketing and the difficulties of applying general marketing techniques in the Jordan Museum and highlighting the strengths, weakness, threats and opportunities that are facing the museum. The paper offers marketing suggestions that may influence and assist the Jordan museum to enhance its marketing structure. The gained information for the research was obtained byusing articles, books, case studies, interviews. This method is used to gain Varity of information, points of views, and attitudes. The questions deducted in the interviews focused on whether if the Museum in question is placed on the well-known tourist trail. Another focus was upon the tools & techniques should be used in marketing. The paper also investigated if there is any marketing plan considered and whether the museums in Jordan has been discussed or even mentioned in any of the international tourism or cultural conference’s Which Jordan is invited to. The result showed that The Jordan Museum lacks any marketing innovation and having no clear marketing plan. The museum can overcome this by reconsidering its priorities enclosing new marketing techniques. Key Words: Museums, Marketing mix, Nonprofit Organization DOI: 10.7176/JTHS/40-0
Optically-triggered deterministic spiking regimes in nanostructure resonant tunnelling diode-photodetectors
This work reports a nanostructure resonant tunnelling diode-photodetector (RTD-PD) device and demonstrates its operation as a controllable, optically-triggered excitable spike generator. The top contact layer of the device is designed with a nanopillar structure (500 nm in diameter) to restrain the injection current, yielding therefore lower energy operation for spike generation. We demonstrate experimentally the deterministic optical triggering of controllable and repeatable neuron-like spike patterns in the nanostructure RTD-PDs. Moreover, we show the device's ability to deliver spiking responses when biased in either of the two regions adjacent to the negative differential conductance region, the so-called 'peak' and 'valley' points of the current–voltage (I–V) characteristic. This work also demonstrates experimentally key neuron-like dynamical features in the nanostructure RTD-PD, such as a well-defined threshold (in input optical intensity) for spike firing, as well as the presence of spike firing refractory time. The optoelectronic and chip-scale character of the proposed system together with the deterministic, repeatable and well controllable nature of the optically-elicited spiking responses render this nanostructure RTD-PD element as a highly promising solution for high-speed, energy-efficient optoelectronic artificial spiking neurons for novel light-enabled neuromorphic computing hardware
Tuneable presynaptic weighting in optoelectronic spiking neurons built with laser-coupled resonant tunneling diodes
Optoelectronic spiking neurons are regarded as highly promising systems for novel light-powered neuromorphic computing hardware. Here, we investigate an optoelectronic (O/E/O) spiking neuron built with an excitable resonant tunnelling diode (RTD) coupled to a photodetector and a vertical-cavity surface-emitting laser (VCSEL). This work provides the first experimental report on the control of the amplitude (weighting factor) of the fired optical spikes directly in the neuron, introducing a simple way for presynaptic spike amplitude tuning. Notably, a very simple mechanism (the control of VCSEL bias) is used to tune the amplitude of the spikes fired by the optoelectronic neuron, hence enabling an easy and high-speed option for the weighting of optical spiking signals in future interconnected photonic spike-processing nodes. Furthermore, we validate the feasibility of this layout using a simulation of a monolithically-integrated, RTD-powered, nanoscale optoelectronic spiking neuron model, confirming the system's potential for delivering weighted optical spiking signals at very high speeds (GHz firing rates). These results demonstrate the high degree of flexibility of RTD-based artificial optoelectronic spiking neurons and highlight their potential towards compact, high-speed and low-energy photonic spiking neural networks for use in future, light-enabled neuromorphic hardware
Characterization of a compact wideband microwave metasurface lens for cryogenic applications
In this paper, we present characterization of a compact flat microwave lens operating between 6 GHz and 14 GHz using a near field scanning system. An X-band horn antenna and open-end rectangular waveguide were used as an illumination source and probe, respectively. |S21| is measured as the probe antenna moves on a plane orthogonal to the optical axis vertically and horizontally. The lens is made of a metasurface layer that is sandwiched by two layers of cross-oriented gratings. The overall dimension of the lens is 10 cm in diameter and 0.57 cm in thickness. The measurement results show that the lens's focal length is 8 cm, and the beamwidth (full width at half maximum (FWHM)) is 3.5 cm, A transmission efficiency of over 90% and a cross-polarization gain of 25 dB were achieved over the entire bandwidth. The measurement results at room temperature are in good agreement with numerical simulations. The proposed lens will be used in a cryogenic environment e.g. dilution refrigerators for quantum computing systems. More results at cryogenic temperature e.g, below 30 K will be shown at the conference
Artificial optoelectronic spiking neuron based on a resonant tunnelling diode coupled to a vertical cavity surface emitting laser
Excitable optoelectronic devices represent one of the key building blocks for implementation of artificial spiking neurons in neuromorphic (brain-inspired) photonic systems. This work introduces and experimentally investigates an opto-electro-optical (O/E/O) artificial neuron built with a resonant tunnelling diode (RTD) coupled to a photodetector as a receiver and a vertical cavity surface emitting laser as a transmitter. We demonstrate a well-defined excitability threshold, above which the neuron produces optical spiking responses with characteristic neural-like refractory period. We utilise its fan-in capability to perform in-device coincidence detection (logical AND) and exclusive logical OR (XOR) tasks. These results provide first experimental validation of deterministic triggering and tasks in an RTD-based spiking optoelectronic neuron with both input and output optical (I/O) terminals. Furthermore, we also investigate in simulation the prospects of the proposed system for nanophotonic implementation in a monolithic design combining a nanoscale RTD element and a nanolaser; therefore demonstrating the potential of integrated RTD-based excitable nodes for low footprint, high-speed optoelectronic spiking neurons in future neuromorphic photonic hardware
Low Optical Limiting and Nonlinear Optical Properties of Vanadyl Phthalocyanine using a CW Laser
Vanadyl phthalocyanine complex has been prepared and characterized by FT- IR, Differential Scanning Calorimetry (DSC) and elemental analysis. The third-order nonlinear optical and optical limiting properties for solution of vanadyl phthalocyanine have been investigated using a continuous wave laser at 635 nm. We have employed the Z-scan technique to evaluate the sign and magnitude of nonlinear refractive index and nonlinear absorption coefficient. The concentration dependent nonlinear refractive index was observed in this medium. We have observed low power optical limiting action, with low limiting thresholds, based on nonlinear refraction in the medium. It indicates that the vanadyl phthalocyanines could be promising candidates for optical limiting materials. Keywords: Z-scan, Optical material, Optical limitin
A Study of the Prevalence and Risk Factors of Diabetes in Children in Iraq
This study aims to know the prevalence of diabetes among children in Iraq were. A cross-sectional study was conducted from different hospitals in Kirkuk, Iraq. where 120 patients were collected, and the patients were divided into 37 boys and 83 girls. This was designed in order to know the study and prevalence of diabetes in Iraqi children, and we concluded in the study there was no difference in the incidence of diabetes between female and male children and that there was a positive linear relationship between obesity (or higher body mass index) and the incidence of diabetes
Розробка механічних і втомних властивостей AA7001 після комбінованого дробеструйного очищення з глибокою кріогенною обробкою та ультразвукової ударної обробки з глибокою кріогенною обробкою
Al alloys have long been of interest to the aerospace community, due to their modest specific strength, ease of manufacture, and low cost. In recent years, with the rapid development of weaponry, 7XXX ultra-high strength aluminum alloys used increasingly in military fields. Chemical analysis of the AA 7001 is supported out at The Company State for Engineering, Rehabilitation and Inspection (SIER) in Iraq. Strengthening the surface (shot penning) is beneficial to delay crack nucleation and extend life. The test samples (tensile and fatigue) are subject to the SP process by using ball steel with the parameters (Pressure=12 bars, Speed=40 mm/min, Distance=150 mm, Shot size=2.25 mm, Coverage=100 %). The ultrasonic impact treatment (UIP) machine is used for enhancing the surface properties. For the Deep Cryogenic Treatment (DCT), the samples have been placed in the cooling chamber. A standard tensile test specimen is prepared in a round section with the dimensions chosen according to ASTM (A370-11). Tensile and fatigue of rotating bending with R=–1 have been conducting, after the effect of deep cryogenic treatment (DCT), combined shot peening (SP+DCT), and ultrasonic impact peening (UIP+DCT) of AA7001 have been examining. The maximum improvement percent in ultimate tensile strength (UTS) due to (DCT), (SP+DCT), and (UIP+DCT) were about 3 %, 8.27 %, and 6.25 %, respectively. The rise in the yield stress due to (DCT), (SP+DCT), and (UIP+DCT) were 9.5 %, 14.6 %, and 13.14 %, respectively. The ductility reduced by constituents of 8.57 %, 12.5 %, and 11.42 % sequentially. The improvement in fatigue strength in a high cycle regime is 16 % for (SP+DCT) due to combined effects, it is an 8 % increase in the endurance limit on fatigue behavior due to inducing compressive residual stress (CRS)Сплавы алюминия давно представляют интерес для аэрокосмического сообщества из-за их удельной прочности, простоты изготовления и низкой стоимости. В последние годы, с быстрым развитием вооружения, сверхвысокопрочные алюминиевые сплавы 7XXX все чаще используются в военных целях. Химический анализ AA 7001 проводится при поддержке Государственной компании по проектированию, реабилитации и инспекции (SIER) в Ираке. Укрепление поверхности (дробеструйная обработка) помогает замедлить зарождение трещин и продлить срок службы. Образцы для испытаний (на растяжение и усталость) подвергаются процессу дробеструйной очистки (ДО) с использованием шариковой стали с параметрами (давление=12 бар, скорость=40 мм/мин, расстояние=150 мм, размер выстрела=2,25 мм, охват=100 %) . Машина для ультразвуковой ударной обработки (УУО) используется для улучшения свойств поверхности. Для глубокой криогенной обработки (ГКО) образцы помещали в охлаждающую камеру. Стандартный образец для испытания на растяжение готовится в круглом сечении с размерами, выбранными в соответствии с ASTM (A370-11). После изучения эффекта глубокой криогенной обработки (ГКО), комбинированного дробеструйного упрочнения (КДО + ГКО) и ультразвукового ударного упрочнения (УУО + ГКО) AA7001 были проведены растяжение и усталость вращающегося изгиба с R=-1. Максимальный процент улучшения предела прочности на разрыв (ППР) за счет (ГКО), (ДО + ГКО) и (УУО + ГКО) составлял около 3 %, 8,27 % и 6,25 % соответственно. Повышение предела текучести из-за (ГКО), (ДО + ГКО) и (УУО + ГКО) составило 9,5 %, 14,6 % и 13,14 % соответственно. Пластичность последовательно снижалась на 8,57 %, 12,5 % и 11,42 %. Повышение усталостной прочности в многоцикловом режиме составляет 16 % для (ДО + ГКО) из-за комбинированных эффектов, это увеличение на 8 % предела выносливости для усталостных характеристик из-за индуцирования остаточного напряжения сжатия (ОНС)Сплави алюмінію давно становлять інтерес для аерокосмічної спільноти через їхню питому міцність, простоту виготовлення та низьку вартість. В останні роки, зі швидким розвитком озброєння, надвисокоміцні алюмінієві сплави 7XXX дедалі частіше використовуються у військових цілях. Хімічний аналіз AA 7001 проводиться за підтримки Державної компанії з проектування, реабілітації та інспекції (SIER) в Іраку. Зміцнення поверхні (дробеструминна обробка) допомагає уповільнити зародження тріщин і продовжити термін служби. Зразки для випробувань (на розтягування та втому) піддаються процесу дробеструминного очищення (ДО) з використанням кулькової сталі з параметрами (тиск=12 бар, швидкість=40 мм/хв, відстань=150 мм, розмір пострілу=2,25 мм, охоплення=100 %). Машина для ультразвукової ударної обробки (УУО) використовується для покращення властивостей поверхні. Для глибокої кріогенної обробки (ГКО) зразки поміщали в камеру, що охолоджує. Стандартний зразок для випробування на розтягування готується у круглому перерізі з розмірами, вибраними відповідно до ASTM (A370-11). Після вивчення ефекту глибокої кріогенної обробки (ГКО), комбінованого дробеструминного зміцнення (КДО + ДКО) та ультразвукового ударного зміцнення (УУО + ДКО) AA7001 були проведені розтягування та втома обертового вигину з R=-1. Максимальний відсоток покращення межі міцності на розрив (ММР) за рахунок (ДКО), (ДО + ГКО) та (УУО + ДКО) становив близько 3 %, 8,27 % та 6,25 % відповідно. Підвищення межі плинності через (ДКО), (ДО + ГКО) та (УУО + ДКО) склало 9,5 %, 14,6 % та 13,14 % відповідно. Пластичність послідовно знижувалася на 8,57 %, 12,5 % та 11,42 %. Підвищення міцності втоми в багатоцикловому режимі становить 16 % для (ДО + ГКО) через комбінованих ефектів, це збільшення на 8 % межі витривалості для втомних характеристик через індукування залишкової напруги стиснення (ЗНС
Estimation of Salt Intake and its Relation to Knowledge and Attitude Regarding the Dangers of High Salt Intake Among an Urban Omani Population: A pilot study
Objectives: High salt consumption is a major risk factor for hypertension. Studies have shown dietary salt intake to be high in many parts of the world. The aim of this study was to assess the daily salt consumption by the urban population in Oman and to assess their knowledge and attitudes towards dietary salt. Methods: This was a cross-sectional questionnaire-based study conducted between September to December 2017 in Muscat. We used previously validated questionnaires to assess salt intake and the knowledge and attitudes to salt intake. Results: 345 responses were received out of 500 distributed questionnaires (response rate 69%) of which 300 responses (27.88 + 7.9 years, 53.3% male) were included for analysis. 94% of the participants agreed that lowering salt in diet is important and nearly half the participants said that they were taking measures to reduce salt intake. However, the median salt intake was high at 10.5(7.3-15.1) gm salt/day. 90% of those questioned consume more than the maximum recommended amount of salt per day. Salt intake was significantly higher in females and older age group (>40 years of age), There did not appear to be any correlation between awareness of the dangers of salt intake and the amount consumed. Conclusion: The salt intake in our sampled population in Oman is high and does not depend on knowledge. Strategies should be designed to reduce salt intake by health education and increasing knowledge about complications of high salt intake among the urban population.
Keywords: dietaray sodium chloride; knowledge attitudes and practices