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直升机卫星通信采用分集合并技术提高性能

直升机卫星通信采用分集合并技术提高性能

作者： Zaheer ruba 电子科技大学

学位级别：硕士

直升机在自然灾害、紧急救援和军事侦察等场景都有十分显著的应用,在这些场景下大多数其他系统通常都已经失效,此外,直升机也可以比较容易提供运输和支援作用。在自然灾害和敌军破坏等情况下通信网络可能已经失效,若由于这些破坏而失去... 详细信息

直升机在自然灾害、紧急救援和军事侦察等场景都有十分显著的应用,在这些场景下大多数其他系统通常都已经失效,此外,直升机也可以比较容易提供运输和支援作用。在自然灾害和敌军破坏等情况下通信网络可能已经失效,若由于这些破坏而失去通信能力,直升机也就失去了其利用价值。而直升机卫星通信可以稳定提供有效可靠的高速通信,因此直升机的重要利用价值和其对通信的需求推动了人们对直升机卫星通信的研究。直升机卫星通信研究的核心论文内容主要包括直升机旋翼遮挡模型、采用时分复用的沃什-哈达玛编码。本文首先研究了直升机卫星通信信道的属性和特点,然后基于一些成熟的信道模型提出了带旋翼遮挡的衰减信道模型。在MATLAB仿真中都采用了这个信道模型,并且也使用了针对其他问题的技术。致力于提高直升机卫星通信性能,本文首先研究了采用码分复用的沃什-哈达玛变换的系统。然后该系统采用精确的双重时间分集来减少码间干扰并改善了系统。本文中也这些系统模型进行了仿真和分析。更进一步地,前面提到的系统模型在其接收端通过分集合并得到改进和提升。分集合并方案已经被证明为是解决旋翼遮挡问题的最优方案并且提升了其传输速率。本文也对包括双重时间分集合并的通信系统进行了仿真、分析和对比。所提出系统的误比特率在低信噪比情况下得到显著地降低,并且性能提高了1dB。

关键词：直升机卫星通信沃什-哈达玛变换信道模型时间分集等增益合并最大笔合并

Hybrid Data Mining Models for Predicting Customer Churn

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International Journal of Communications, Network and System Sciences 2015年第5期8卷 91-96页

作者： Amjad Hudaib Reham Dannoun Osama Harfoushi ruba Obiedat Hossam Faris King Abdullah II School of Information Technology The University of Jordan Amman Jordan

The term “customer churn” is used in the industry of information and communication technology (ICT) to indicate those customers who are about to leave for a new competitor, or end their subscription. Predicting this behavior is very important for real life market and competition, and it is essential to manage it. In this paper, three hybrid models are investigated to develop an accurate and efficient churn prediction model. The three models are based on two phases;the clustering phase and the prediction phase. In the first phase, customer data is filtered. The second phase predicts the customer behavior. The first model investigates the k-means algorithm for data filtering, and Multilayer Perceptron Artificial Neural Networks (MLP-ANN) for prediction. The second model uses hierarchical clustering with MLP-ANN. The third one uses self organizing maps (SOM) with MLP-ANN. The three models are developed based on real data then the accuracy and churn rate values are calculated and compared. The comparison with the other models shows that the three hybrid models outperformed single common models.

关键词： Data Mining k-Means Hierarchical Cluster Self Organizing Maps Multilayer Perceptron Artificial Neural Networks Churn Prediction

汉阿交替传译中信息缺失的原因及其解决方案——以2020年周小川在“外滩金融峰会”的演讲模拟会议为例

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汉阿交替传译中信息缺失的原因及其解决方案——以2020年周小川在...

作者： ruba Yousif Mahmoud Ibrahim 上海外国语大学

学位级别：硕士

信息缺失会降低译员的口译质量,造成交流障碍,产生负面影响,也会影响译员的信心。笔者对模拟会议录音进行了转写、整理和分析,经研究发现,口译中产生信息缺失的原因包括客观原因和主观原因,其中的主观原因主要包括听辨能力不足、背景知... 详细信息

信息缺失会降低译员的口译质量,造成交流障碍,产生负面影响,也会影响译员的信心。笔者对模拟会议录音进行了转写、整理和分析,经研究发现,口译中产生信息缺失的原因包括客观原因和主观原因,其中的主观原因主要包括听辨能力不足、背景知识不足和笔记有效性不足等,基于此,笔者决定对这些原因进行深入探讨,并提出对应的解决方案。本文研究的案例为2020年周小川在“外滩金融峰会”的演讲模拟会议,会议演讲者为周小川,其讨论的话题是疫情之后的“一带一路”。信息缺失是口译中非常普遍的问题,译员难以避免,但应通过针对性的训练,尽量减少该问题出现的机率。在模拟会议中,笔者作为译员,完成了整场会议的口译任务,在实践中发现,遇到的最突出的就是信息缺失的问题,所以笔者决定以此作为研究的内容,经分析研究,笔者认为,可以采取的解决方案有很多,比如提高汉语语言能力,做好译前准备,扩展知识面,多练习适当使用笔记符号,增强短时记忆能力以及提高逻辑分析能力等等。希望本研究对遇到同类问题的口译学习者及从业人员有借鉴意义。

关键词：汉阿交传信息缺失信息缺失原因及对策

Modeling and Forecasting of SARS CoV-2 Cases in Sierra Leone

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Journal of Biosciences and Medicines 2022年第4期10卷 77-86页

作者： Sallieu Kabay Samura Theresa ruba Koroma Abdul A. Kamara Department of Mathematics and Statistics Fourah Bay College University of Sierra Leone Freetown Sierra Leone Department of Internal Medicine Faculty of Clinical Sciences College of Medicine and Allied Health Sciences University of Sierra Leone Freetown Sierra Leone

Severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) has been a global threat spreading in Sierra Leone, and many studies are being conducted using various Statistical models to predict the probable evolution of this pandemic. In this paper, we use the autoregressive integrated moving average (ARIMA) model with the aim of forecasting the cumulative confirmed cases of SARS CoV-2 in Sierra Leone. The Akaike Information Criterion (AIC) was applied to the training data as a criterion method to select the best model. In addition, the statistical measure RMSE and MAPE were utilized for testing this data, and the model with the minimum RMSE and MAPE was selected for future forecasting. ARIMA (3, 2, 1) was confirmed to be the optimal model based on the lowest AIC value. This model was then applied to study the trend of SARS CoV-2 from 1st February 2022 to 30th February 2022. The result shows that incidence of SARS CoV-2 from 1st February 2022 to 30th February 2022, increasing growth steep in Sierra Leone (7718.629, 95% confidence limit of 6785.985 - 8651.274).

关键词： ARIMA Model SARS Cov-2 Stationarity Forecast

Effectiveness of Bacterial and Fungal Isolates to Control <i>Phoma lingam</i>on Oilseed Rape <i>Brassica napus</i>

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American Journal of Plant Sciences 2012年第6期3卷 773-779页

作者： Omar Hammoudi Mazen Salman ruba Abuamsha Ralf-Udo Ehlers Agriculture Scientific Research Center Lattakia Syria Department of Biotechnology & Biological Control Institute for Phytopathology Christian-Albrechts-University Kiel Kiel Germany National Agriculture Research Center (NARC) Jenin Palestine Palestine Technical University-Kadoorie (PTUK) Tulkarm Palestine

Blackleg disease caused by Phoma lingam is an important disease of oil seed rape (Brassica napus) causing losses up to 95%. The efficacy of microbial antagonists against P. lingam in greenhouse was tested. Serratia plymuthica HRO-C48 and Gliocladium catenulatum J1446 were able to reduce the disease intensity of OSR cotelydones infested with P. lingam at rates 44% and 52% respectively. The reduction of the infestation of the root collar in BBCH14/15 was evaluated as well. Plants treated with a suspension of the antagonists (2 × 105 cfu/plant) and inoculated with either pycnidiospore suspension (2 × 107 cfu/ml) or agar disks grown with P. lingam mycelium, showed a reduced infestation rate of 53% - 93% in the presence of S. plymuthica and 46% - 77% in the presence of G. catenulatum. The efficacy of the antagonist depends highly on their concentration inside OSR seeds. Below 105 cfu/seed no significant difference was recorded between control untreated and infested plants.

关键词： Biological Control Oilseed Rape Phoma lingam Bacteria

Establishment of Dose Reference Levels for Nuclear Medicine in Sudan

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Open Journal of Radiology 2016年第4期6卷 258-263页

作者： Wadah M. Ali ruba Mohamed Elawad Mohmmed Alhadi A. Ibrahim Medical Imaging Department College of Allied Medical Science Gulf Medical University Ajman UAE Nuclear Medicine Department Radiological Science and Nuclear Medicine College The National Ribat University Khartoum Sudan Radiology Department Madina Medical Center Madina City KSA Nuclear Medicine Department Radiation and Isotopes Center of Khartoum Khartoum Sudan

In this study, a national survey for establishment of Nuclear Medicine (NM) Dose Reference Levels (DRLs) for adult patients was carried out. The Administrated Activity (AAs) (MBq) was collected from six nuclear medicine departments. Factors influencing the image quality were also observed. The established Sudan National DRLs represent the AA value corresponding to 75th percentile of the AA frequency distribution. Generally, Sudan National DRLs and average AAs are comparable with the papers published in the international literature. All Sudanese DRLs values were found within the international range. While it is noted that the Sudanese DRLs is higher than the values of ARSA except for the MIBI pharmaceuticals that used in both parathyroid and myocardial perfusion scan and for 99mTcDTPA that used for Dynamic Renal scan study the DRLs values were decreased. In compared with UNSCEAR 2008 data, the average dose (MBq) for Sudanese we note that the bone scan falls within the average values while it’s lower in all other scans except for parathyroid scan in which the AAAs increase more than twice. When compared to BSS 1996, it showed variation in increased and decreased AAAs. There may be potential for reducing the higher values of AAs, in co-operation with Nuclear Medicine staff.

关键词： Nuclear Medicine Diagnostic Reference Level DRLs

Impact of Internet Advertisement and Its Features on E-Commerce Retail Sales: Evidence from Europe

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Journal of Software Engineering and Applications 2013年第11期6卷 564-570页

作者： Osama Harfoushi Bader Alfawwaz Bader Obeidat ruba Obiedat Hossam Faris Department of Business Administration The University of Jordan Amman Jordan Department of Business Information Technology The University of Jordan Amman Jordan Department of Computer Information System Al-albayt University Mafraq Jordan

The stimulus to carry out this research is to investigate the relationship between internet advertisement and its features on the total E-commerce sales of the top five countries of Europe. The units of analysis are the individuals of UK, France, Italy, Germany and Netherland. Secondary data are collected from the reports of [1] (ADEX, 2010) and [2] (Eurostats, 2011). To empirically determine the relationship between independent variable and dependent variable in the European context, the study uses various statistical techniques, including OLS regression and correlation analysis techniques. The empirical findings indicate that the Internet advertisement features of search advertisement and classified advertisement have positive significant relationship with the E-commerce sales in Europe. The empirical findings indicate negative significant relationship of display advertisement with the E-commerce sales in Europe. However, this variable is also justified with the help of literature. Findings also demonstrate that search advertisement has strong positive relationship and it generates positive influence for the E-commerce sales as compared to the classified advertisement and display advertisement. Firms and marketers which are investing in online advertisement will find these results useful as they can get better sales and can use these features of online advertisement in order to maximize the sales of their products and services.

关键词： Features of Internet Advertisement Display Advertisement Search Advertisement Classified Advertisement E-Commerce Sales E-Commerce Sale in Europe

Safe Disposal of Medicines in Palestine

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Journal of Pharmacy and Pharmacology 2016年第1期4卷 17-22页

作者： Qusai N. Al-Shahed Anhar Assali ruba Najjar Al- Hayat Company for Studies and Research Al- Isra' Building Sufian st. Nablus P.O.Box 167 Palestine

The disposal of unwanted and expired medications has been a concern to public health practitioners, and patients alike. The objective of the current investigation was to look closely at the practice of patients and carers in Nablus-Palestine with regard to disposal of unused or expired medicines. The study was a cross-sectional survey administered via face-to-face structured interviews with randomly selected patients, community pharmacists and physicians from Nablus-Palestine. Two hundred and fifty patients/carers completed a questionnaire regarding medicines disposal current practice, effects on environment, and their views to overcome this problem. Most of the people completing the questionnaire （67%） stated that they throw unwanted medicines in the normal household bins, and about 75% think that this can impose illegal and environmental hazards. Nearly half of the questionnaire showed that main reason for need to dispose medicines was possessing expired ones with almost believe there should be more appropriate way to dispose medicines. About 95% said they have not been directed for safe disposal of medicines with 46% thinking that a national campaign can be very educative in this issue mainly through Ministry of Health （54%） followed by .73% of the sampled patients were in favor of national campaign to direct people to safe disposal of medicines. This pilot study in Nablus clearly highlights the need for appropriate method for safe disposal of medicines in Palestine through guidelines in pharmacies and hospitals. A well organized method for collecting unwanted medicines from people should be encouraged through appropriate teaching of patients and caters about effects of waste medicines on environment as well as being domestic hazard. The data and information is valuable for furthering discussions regarding patients behaviour and also provides a basis for future research into determining what quantities of active pharmaceutical ingredients （APIs） are disposed, ent

关键词： Active pharmaceutical ingredients medicines disposal medicine use.

Using Malmquist Index Approach to Measure Productivity Change of a Jordanian Company for Plastic Industries

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American Journal of Operations Research 2015年第5期5卷 384-400页

作者： Abbas Al-Refaie Mohammad D. Al-Tahat ruba Najdawi Department of Industrial Engineering University of Jordan Amman Jordan

Measurement of a production unit-performance is crucial in determining whether it has achieved its objectives or not, and it generates a phase of management process that consists of feedback motivation phases. The purpose of this paper is to analyze the growth potentials of five production machines in a Jordanian company for plastic industries by employing the non-parametric Malmquist productivity index (MPI) over the period from February to July 2014 in both day and night shifts. The productivity change is decomposed into technical efficiency change (TEC) and technological change (TC). Inefficiency values are observed in each period. The percentage of input utilization is determined in all periods. Then, the Malmquist productivity index (MPI) values are calculated for all periods. Finally, comparisons of TEC, TC and MPI are conducted among the five machines and between the day and night shifts for each machine. The MPI results indicate that the needs for internal training, effective operating procedures, and enhancing quality procedures are required to increase the technical efficiency. On the other hand, figuring out more efficient ways of making existing products allowing output to grow at a faster rate than economic inputs, like using new technologies, will increase technological change. In conclusions, Malmquist model analysis shall provide valuable reference information to management when evaluating the progress in the performances of production machines in plastic industry.

关键词： Malmquist Index Technical Efficiency Technological Efficiency Plastic Industry