إحدى أهم الطرق لتقصي توزيع المجرات عبر الزمن الكوني هي دالة اللمعان LF بدلالة كتلة القرص الباريوني ψS(Mb)، القدر . لقد درسنا تقديرًا لكثافة كتلة الباريون في عينة من المجرات الحلزونية القضيبية وغير القضيبية من الادبيات السابقة، والتي تتضمن فعليًا، لكل صنف من الاجرام السماوية ذات المحتوى الباريون المرئي، جزءًا لا يتجزأ من ناتج دالة الضيائية (LF) ونسبة الكتلة إلى الضوء. استخدمت تقنية الانحدار المتعدد لحزمة البرامج الإحصائية في دراستنا ونتائجنا، مثل برنامج تحليل قواعد البيانات والرسوم البيانية)برامج Statistics Win و(Origin Pro . وفقًا للتحليل الإحصائي، هناك علاقة إيجابية قوية وارتباط وثيق للغاية (α MB~1), ، وغالبًا ما تظهر المجرات الحلزونية القرصية القضيبية وغير القضيبية قدراً مطلقاً بحدود MB < -18 mag . "الركبة" لدالة الضيائية للمجرات الحلزونية تبين قطعًا كبيرًا عند كتلة باريونية تبلغ Mb > 1010 Mʘ للمجرات الحلزونية القضيبية وغير القضيبية. يوفر هذا دليلاً يدعم الفرضية القائلة بأن اللوالب الحلزونية لنظام القرص بدأت تتشكل داخل عتبة كتلة متزايدة. نظرًا لأن زيادة دالة الكتلة الأولية للنجم مع الانزياح نحو الأحمر تكون أسرع بكثير، فقد أشارت النتائج التي توصلنا إليها إلى أن دالة الكتلة الأولية المنتقلة ψS(Mb) للمجرات القضيبية وغير القضيبيةعند انزياح أحمر مرتفع z > 0.027 للمجرات االقضيبية وz > 0.02للمجرات غير القضيبية والذي يبدو أنه يتناقص مقارنة بالكون الحرج.
The choice of binary Pseudonoise (PN) sequences with specific properties, having long period high complexity, randomness, minimum cross and auto- correlation which are essential for some communication systems. In this research a nonlinear PN generator is introduced . It consists of a combination of basic components like Linear Feedback Shift Register (LFSR), ?-element which is a type of RxR crossbar switches. The period and complexity of a sequence which are generated by the proposed generator are computed and the randomness properties of these sequences are measured by well-known randomness tests.
The growing interest in the use of chaotic techniques for enabling secure communication in recent years has been motivated by the emergence of a number of wireless services which require the service provider to provide low bit error rates (BER) along with information security. This paper investigates the feasibility of using chaotic communications over Multiple-Input-Multiple-Output (MIMO) channels. While the use of Chaotic maps can enhance security, it is seen that the overall BER performance gets degraded when compared to conventional communication schemes. In order to overcome this limitation, we have proposed the use of a combination of Chaotic modulation and Alamouti Space Time Block Code. The performance of Chaos Shift Keying (CSK) wi
... Show MoreThere has been a growing interest in the use of chaotic techniques for enabling secure communication in recent years. This need has been motivated by the emergence of a number of wireless services which require the channel to provide very low bit error rates (BER) along with information security. This paper investigates the feasibility of using chaotic communications over Multiple-Input Multiple-Output (MIMO) channels by combining chaos modulation with a suitable Space Time Block Code (STBC). It is well known that the use of Chaotic Modulation techniques can enhance communication security. However, the performance of systems using Chaos modulation has been observed to be inferior in BER performance as compared to conventional communication
... Show MoreConsiderable amounts of domestic and industrial wastewater that should be treated before reuse are discharged into the environment annually. Electrocoagulation is an electrochemical technology in which electrical current is conducted through electrodes, it is mainly used to remove several types of wastewater pollutants, such as dyes, toxic materials, oil content, chemical oxygen demand, and salinity, individually or in combination with other processes. Electrocoagulation technology used in hybrid systems along with other technologies for wastewater treatment are reviewed in this work, and the articles reviewed herein were published from 2018 to 2021. Electrocoagulation is widely employed in integrated systems with other electrochemical tech
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Suffering the human because of pressure normal life of exposure to several types of heart disease as a result of due to different factors. Therefore, and in order to find out the case of a death whether or not, are to be modeled using binary logistic regression model
In this research used, one of the most important models of nonlinear regression models extensive use in the modeling of applications statistical, in terms of heart disease which is the binary logistic regression model. and then estimating the parameters of this model using the statistical estimation methods, another problem will be appears in estimating its parameters, as well as when the numbe
... Show MoreIn this paper, the survival function has been estimated for the patients with lung cancer using different parametric estimation methods depending on sample for completing real data which explain the period of survival for patients who were ill with the lung cancer based on the diagnosis of disease or the entire of patients in a hospital for a time of two years (starting with 2012 to the end of 2013). Comparisons between the mentioned estimation methods has been performed using statistical indicator mean squares error, concluding that the estimation of the survival function for the lung cancer by using pre-test singles stage shrinkage estimator method was the best . <
... Show MoreThis paper deals with the modeling of a preventive maintenance strategy applied to a single-unit system subject to random failures.
According to this policy, the system is subjected to imperfect periodic preventive maintenance restoring it to ‘as good as new’ with probability
p and leaving it at state ‘as bad as old’ with probability q. Imperfect repairs are performed following failures occurring between consecutive
preventive maintenance actions, i.e the times between failures follow a decreasing quasi-renewal process with parameter a. Considering the
average durations of the preventive and corrective maintenance actions a
... Show MoreThe unstable and uncertain nature of natural rubber prices makes them highly volatile and prone to outliers, which can have a significant impact on both modeling and forecasting. To tackle this issue, the author recommends a hybrid model that combines the autoregressive (AR) and Generalized Autoregressive Conditional Heteroscedasticity (GARCH) models. The model utilizes the Huber weighting function to ensure the forecast value of rubber prices remains sustainable even in the presence of outliers. The study aims to develop a sustainable model and forecast daily prices for a 12-day period by analyzing 2683 daily price data from Standard Malaysian Rubber Grade 20 (SMR 20) in Malaysia. The analysis incorporates two dispersion measurements (I
... Show MoreIn this paper we proposes the philosophy of the Darwinian selection as synthesis method called Genetic algorithm ( GA ), and include new merit function with simple form then its uses in other works for designing one of the kinds of multilayer optical filters called high reflection mirror. Here we intend to investigate solutions for many practical problems. This work appears designed high reflection mirror that have good performance with reduction the number of layers, which can enable one to controlling the errors effect of the thickness layers on the final product, where in this work we can yield such a solution in a very shorter time by controlling the length of the chromosome and optimal genetic operators . Res
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