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Article
Studying the Parameters of EDM Based Micro- Cutting Holes Using ANOVA
دراسة العوامل للتشغیل بالشرارة الكھربائیة لقطع الثقوب الدقیقة ANOVA

Authors: Shukry H. Aghdeab --- Laith A. Mohammed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2013 Volume: 31 Issue: 15 Part (A) Engineering Pages: 2876-2884
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Micro -EDM is one of an important method in machining holes which is used in wideapplications to fabricate medical devices and small dies. This work study the process ofproducing micro holes for copper alloy workpieces using, stainless steel electrodeand dielectric solution (tap water), using DC current and low voltage (70V) to cut(0.7mm) thickness of copper (Cu) alloy workpieces in order to obtain the micro holes.This work included an experimental work for electrical discharge machining(EDM) to produce micro holes with different diameters (400, 300, 210, 200, 120,100, 85, 75, 70) μm.The objective of this work is to obtain an optimal setting of EDM parameters toproduce micro holes in copper alloy to achieve the optimal values of required holesdiameters.A regression model has been developed to represent this process. An approachhas been made to optimize the process parameters (current, gap distance, machiningtime) using ANOVA analysis. This analysis was performed to obtain the mostsignificant factors influencing the production of micro holes.

Keywords

EDM --- Regression Model --- ANOVA


Article
Robust Estimators of Logistic Regression with Problems Multicollinearity or Outliers Values.

Authors: Fadhil Abbul Abbas AL- Aabdi --- Rafid Malik Atiyah AL – Shaibani
Journal: Journal of Kufa for Mathematics and Computer مجلة الكوفة للرياضيات والحاسوب ISSN: 11712076 Year: 2014 Volume: 2 Issue: 2 Pages: 64-71
Publisher: University of Kufa جامعة الكوفة

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Abstract

Whenever there is a relationship between the explanatory variables (X_S). This relationship causes multicollinearity which in turn leads to inaccurate and bias estimations of the model parameters. Therefore, this results in high discrepancy that influences the next phase of the statistical inference where (OLS), method loses its features having the lowest variance. Consequently, this paper concerns itself with figuring out methods that can be applied by researchers and those who are interested in this field to overcome this problem using (Ridge) method. Moreover, the paper seeks to solve other problems such as the loss of normal distribution property or abnormalility by means of methodical means including (Ridge) and (Robust Ridge). However this study is applied through simulation experiments aim at producing the data of the model. Based on these experiments and tests, the research has come up with the result that (Robust Ridge) is the best method that might be employed to solve the problem of has both normal and abnormal data for the estimation of the parameters of the Logistic Regression Model.


Article
Re-sampling Techniques in Count Data Regression Models
أساليب إعادة المعاينة في نماذج انحدار بيانات العد

Author: Zakariya Y. Algamal
Journal: IRAOI JOURNAL OF STATISTICAL SCIENCES المجلة العراقية للعلوم الاحصائية ISSN: 1680855X Year: 2012 Volume: 12 Issue: 22 Pages: 15-25
Publisher: Mosul University جامعة الموصل

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Abstract

Modeling count variables is a common task in many application areas such as economics, social sciences, and medicine. The classical Poisson regression model for count data is often used and it is limited in these disciplines since count data sets typically exhibit overdispersion, so negative binomial regression can be used. We use a jackknife- after- bootstrap procedure to assess the error in the bootstrap estimated parameters. The method is illustrated through two real examples. The results suggest that the jackknife- after- bootstrap method provides a reliable alternative to traditional methods particularly in small to moderate samples.

تعد عملية نمذجة المتغيرات القابلة للعد من المهام المهمة في العديد من المجالات منها الاقتصادية والعلوم الاجتماعية والطبية . غالبا ما يستخدم نموذج انحدار بواسون لنمذجة مثل هذا النوع من البيانات ويكون هذا النموذج غير ملائم عندما يعاني من مشكلة (Overdispersion)وعليه سوف يستخدم نموذج انحدار ثنائي الحدين السالب . وقد استخدمنا في هذا البحث أسلوب (Jackknife- after- Bootstrap) لتقييم الخطأ الذي يحصل عند تقدير المعلمات باستخدام الـ (Bootstrap) في انحدار بواسون ، إذ استخدمنا مجموعتين من البيانات الحقيقية لتوضيح الأسلوب المستخدم وقد وضحت النتائج بان استخدام أسلوب (Jackknife- after- Bootstrap) يمكن التعويل عليه مقارنة بالطرائق التقليدية وخاصة عند أحجام العينات الصغيرة والمتوسطة .


Article
Estimating Fuzzy Linear Regression Model for Air Pollution Predictions in Baghdad City

Authors: Suhaila Najma Alsoltany --- Iftikhar Abdulhamed Alnaqash
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2015 Volume: 18 Issue: 2 Pages: 157-166
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

Regression analysis is one f the basic tools of scientific investigation of functional relationship between dependent and independent variables, For many years linear regression models has been used in almost every field of science. The purpose of regression analysis is to explain the variation of dependent variables in terms of the variation of explanatory variables, residuals are assumed to be due to random errors, however the residuals are sometimes due to the indefiniteness of the model structure or imprecise observations, the uncertainty in this type of regression model becomes fuzziness, not random.The aim of this paper is to study and applied the method of estimation fuzzy linear regression parameters using fuzzy data collecting from (145) sample in three stations (Andalus square, jadiriya, alawi) in Bagdad city every day, In order to measurements the concentrations of airborne stuck which represents the response variable, and also the most important air pollutants, namely, (lead, zinc, copper, iron, nickel, chromium, cadmium) as independents variables the main result identify the best techniques to estimate the fuzzy linear regression parameters for this data and calculates the expected value of the concentrations of airborne stuck in Bagdad city for the next years.

تحليل الانحدار من الادوات الاساسية للفحص العلمي للعلاقة الدالية بين المتغير المعتمد والمتغيرات المستقلة، ولسنوات عديدة نماذج الانحدار الخطي استخدمت على الاكثر في كل حقل من الحقول العلمية. الغرض من تحليل الانحدار هو توضيح التغير الحاصل في المتغير المعتمد بدلالة التغيرات الحاصلة في المتغيرات التوضيحية بافتراض ان البواقي هي اخطاء عشولئية. على كل حال البواقي في بعض الاحيان تعود الى عدم تحديد هيكلية الأنموذج أو عدم دقة المشاهدات عدم التأكد من هذا النوع في نماذج الانحدار اصبح يعرف بالضبابية او عدم العشوائية.الهدف من هذا البحث هو دراسة وتطبيق طرائق تقدير معلمات تموذج الانحدار الخطي الضبابي بأستعمال بيانات ضبابية جمعت من 145 عينة فيثلاث محطات هي (ساحة الاندلس، الجادرية، العلاوي) في بغداد على انواع نماذج الانحدار الضبابية من خلال تطبيق عملي على التلوث البيئي لهواء مدينة بغداد, حيث تم جمع ديتة بغداد كل يوم لغرض قياس تراكيز الدقائق العالقة في الهواء في والذي يمثل متغير الاستجابة كذلك اهم ملوثات الهواء المعروفة (الرصاص، الخارصين، النحاس، الحديد، النيكل، الكروم، الكادميوم) كمتغيرات التوضحية، النتيجة الرئيسية للبحث تحديد افضل اسلوب لتقدير معلمات الانحدار الخطي الضبابي لهذه البيانات وحساب القيم التنبؤية للدقائق العالقة في الهواء لمدينة بغداد للسنوات القادمة.


Article
PREDICTING MICROVASCULAR COMPLICATIONS IN DIABETIC PATIENTS

Author: Yousif AR Al Ani يوسف عبد الرحيم عبد الغفور العاني
Journal: IRAQI JOURNAL OF MEDICAL SCIENCES المجلة العراقية للعلوم الطبية ISSN: P16816579,E22244719 Year: 2011 Volume: 9 Issue: 3 Pages: 195-205
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

BackgroundPatients with diabetes have an increased risk of developing microvascular complications, diabetic retinopathy, diabetic nephropathy and diabetic neuropathy, which if not predicted, early detected and treated, place a significant burden on individual’s health and can reduce life expectancy.ObjectiveTo determine the main risk factors (predictors) that associated with microvascular complications in diabetes aiming to construct a module that can detect microvascular complications depending on these predictors.MethodsA cross sectional descriptive study was carried out with 364 diabetic patients. Data about diabetes microvascular complications (retinopathy, clinical peripheral neuropathy, and nephropathy) and their potential risk factors were collected. Primary point was detecting the < 0.01 level of significant association of risk factors with these complications to determine the predictors. These predictors were assessed for each individual’s micro vascular complication and also as a composite outcome by logistic regression analysis.ResultOf the examined 364 diabetic cases, 174 (47.80%) patients were found with microvascular complications. Neuropathy, nephropathy, and retinopathy were detected in 66 (18.13%), 62 (17.03), and 46 (12.64%) patients, respectively. Out of 12 potential predictors, only six (age, smoking habit, duration of diabetes, uncontrolled hyperglycemia, hypertension, and macrovascular complications) found to be significantly associated with the presence of microvascular complication (p < 0.01) as compared with patients who had no such complications. Uncontrolled hyperglycemia was the first predictor in neuropathy and nephropathy groups, while diabetic duration was ranking first in retinopathy group.ConclusionsMicrovascular complications in diabetic patients can be predicted, and avoided, by detecting their risk factors. Logistic regression equation provide suitable module for evaluation of these risk factors simultaneously.Key wordsMicrovascular complications, diabetes, logistic regression


Article
EFFECTS OF SMOKING AND AGE ON THE VALIDITY OF PARTIAL DENTURE AFTER TWO YEARS OF USE: STATISTICAL STUDY
تاثير التدخين و العمر على صلاحية اطقم الاسنان الجزئية بعد سنتين من الاستخدام: دراسة احصائية

Author: Salah Khalaf Abbass . صلاح خلف الراوي
Journal: Journal of university of Anbar for Pure science مجلة جامعة الانبار للعلوم الصرفة ISSN: ISSN: 19918941 Year: 2008 Volume: 2 Issue: 2 Pages: 82-87
Publisher: University of Anbar جامعة الانبار

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Abstract

Age and smoking cigarettes were found to contribute significantly to the lifetime of partial denture. Such an effect was determined by the use of the binary logistic regression model.
When smoking cigarettes is compared to age, age of the patient was found to contribute slightly higher (probably ignorable difference) to this matter.

لقد وجد ان عاملي العمر و التدخين يسهمان بشكل جوهري في التاثير على فترة استخدام اطقمالاسنان الجزئية. لقد تم تحديد هذا التاثير من خلال استخدام نموذج الانحدار اللوجستي الثنائي، و لقد وجد انعمر المريض يسهم بشكل اعلى نسبيا من التدخين على فترة استخدام اطقم الاسنان الجزئية.


Article
Multivariate Multisite Model MV.MS. Reg for water Demand Forecasting
للتنبؤ باحتیاجات MV.MS.Reg النماذج المتعددة المواقع والمتغیرات المیاه

Authors: Cheleng A.Arselan --- Muhannad, J.Al-Kazwini --- Rafa H.Shaker.Al-suhaili
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2010 Volume: 28 Issue: 13 Pages: 2516-2529
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

A new multivariate multi site MV.MS.Reg model is developed in thisresearch depended on regression analysis mixed with Auto regressive multisiteMatalas model (AMMM)and used for water demand forecasting .This developedmodel was applied to Kerkuk city as a case study for long term forecasting ofwater demand for different types such as domestic demand,industrial,commercialand public demand.This was done by dividing the city into four sites anddividing the total water demand in each site into three types ofdemand(domestic,industrial with commercial and public demand) .Each type ofwater demand in each site was analyzed by multivariate regression base then thecross correlation between this type of demand for the four sites were included inthe model using multi site Matalas model.Many explanatory variables wereconcluded to be most effective factors affecting different types of demands suchas monthly temperature,monthly evaporation ,number of residential units,number of industrial and commercial units and number of public units whichwere forecasted successfully using Stochastic weather generation (SWG)method.

مع Multivariate regression تم تطوير نموذج رياضي حديث معتمد على دمج أسلوبيلتخمين احتياجات المياه (AMMM)Auto regressive Multi site Matalas اسلوبلمدينة كركوك الواقعة شمال مدينة بغداد.لقد اعتمد النموذج على تقسيم الاستهلاك الكلي للمدينةمن المياه حسب المواقع . لذا تم تقسيم الاستهلاك الفعلي للمدينة للسنوات السابقة الى اربعةمواقع. بعدها تم تحليل البيانات الخاصة بهذا الاستهلاك في هذه المواقع لغرض ايجادالمعاملات الضرورية لبناء النموذج الرياضي الذي اعتمد على فصل الاستهلاك الكلي للمياهلهذه المواقع الى ثلاثة انواع (منزلي ،صناعي وتجاري،عام) . لقد تم ربط كل نوع بمجموعةMultivariate ) من العوامل المؤثرة على الاستهلاك من خلال الاستفادة من النموذجعن طريق تقاطع الارتباط لأنواع الاستهلاك في المواقع الأربعة باستخدام (regressionلقد تبين بان المعدلات .AMMM)Auto regressive)Multisite Matalas model أسلوبالشهرية لدرجات الحرارة والتبخر وعدد الوحدات المخدومة في كل نوع هي العوامل المؤثرة (SWG) على المتطلبات المائية والتي تم ايضا التنبؤ بها بنجاح باستخدام اسلوب.stochastic weather generation

Keywords

Multisite Multivariate --- Regression --- Matalas --- SWG --- AMMM


Article
A combined 2-dimensional fuzzy regression model to study effect of climate change on the electrical peak load

Authors: Hamed Shakouri G. --- Hosain Zaman
Journal: Iraqi Journal for Electrical And Electronic Engineering المجلة العراقية للهندسة الكهربائية والالكترونية ISSN: 18145892 Year: 2010 Volume: 6 Issue: 1 Pages: 45-49
Publisher: Basrah University جامعة البصرة

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Abstract

The intergovernmental panel for climate change predictedthat the average temperature of our planet surface willincrease by 1.4–5.8 °C by the end of 21th century. Limitedresources of energy in joint to the effect of temperature onthe energy consumption together attract our attention to thetemperature changes phenomenon. Therefore, researcheshave focused on the problem, which is the effect of climatechange on the energy consumption.Zmeureanu and Renaud proposed a method forestimation of the impact of climate change on heat energyconsumption in households sector [1]. Peirson and Henleyconsider it as a dynamic problem and also shown that byusing autoregressive specification we can obtain a goodexplanation of present load [2]. Pardo et al. studied therelationship between weather and electricity demand inSpain. They proposed a transfer function intervention modelto predict the electricity demand in the hot and cold days [3].Bessec and Fouquau studied the relationship betweentemperature and electricity consumption in 15 countries ofEuropean Union. They showed the nonlinearity link betweenelectricity consumption and temperature found in morelimited geographical areas in previous studies; also theyshowed that the sensitivity between electricity consumptionand temperature increases in summer [4]. Franco and


Article
Estimation of the Crown Widths of Un-erupted Canine and Premolars by Using Vistibulo-oral Crown Dimensions of Per-manent Teeth

Author: Hind T Jarjees
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2012 Volume: 12 Issue: 24 Pages: 350-355
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: To estimate multiple regression equation on (88) subjects (48 females and 40 males),for predict-ing the widths of crowns of unerupted canine and premolar for both jaws and both genders. The sub-jects had normal class I molar relationship with full permanent dentition. Materials and methods: Plas-ter models of (88) subjects (48 females and 40 males ).Mesiodistal diameter (MMD) and vestibulooral diameter (VOD) of the crown of cental incisor, lateral incisor,canine,premolars and first molar( I1,I2,C both P1 and P2, and M1) on both sides in both jaws were measured. Multiple regression equations and correlation coefficients between the predictors( central incisor,lateral incisor and first molar) and the criteria variables (canine and premolars) were calculated. The data were analyzed by computerized statistical program SPSS. Results: Gradual regression equations were derived on the basis of measure-ment result ,by using three to five predictors to predict the sums of width of crown of unerupted canine and premolars using separated equations for both jaws and both genders (i.e four multiple regression equations were prepared).The coefficients of multiple correlations regarding gender and jaws ranged between 0.70-0.79.Conclusions: Establish regression equations, which would give satisfactory correla-tion coefficient regarding the gender and the jaw varied from 0.70-0.79


Article
Using Dummy Variables in Improving the Simple Linear Regression Model for the Ratio of Consumption to the National Income in Iraq during the Period (1970-1994)

Author: Fedaa N. Abdulahad
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2012 Volume: 15 Issue: 3 Pages: 167-172
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

This paper discuss the concept of dummy variables and its importance usge in statistical analysis by transforming the qualitative variables to measurable quantitative variables and applying it in analyzing the linear regression in both simple and multiple forms. A comparison has been made between using dummy variables and power transformation methodology. This comparison aims to show which one of the two methods is better in improving the linear regression model by applying them on the data of ratio of consumption to the national income in Iraq for the period of (1970-1994). Depending on the data available of that period the results showed that the dummy variables are more efficient than power transformation in improving the regression model of the consumption to national income. The dummy variables helped explaining almost 80% from the consumption ratio in the given period in Iraq by making the data to be more intelligible and more homogeneous in the model

تم في هذا البحث عرض مفهوم المتغيرات الصماء واهمية استخدامها في التحليل الاحصائي وذلك بتحويل المتغيرات النوعية الى متغيرات كمية قابلة للقياس وتطبيق هذه المتغيرات في تحليل الانحدار بشقيه الخطي البسيط والمتعدد. تم اجراء مقارنة بين استخدام المتغيرات الصماء مع استخدام منهجية تحويلات القوى هذه المقارنة تهدف الى بيان اي من الطريقتين المذكورتين الاحسن في تحسين نموذج الانحدار الخطي وذللك بتطبيق الطريقتين على بيانات نسبة الاستهلاك الى الدخل القومي في العراق للفترة (1970-1994). ان البيانات المتاحة في الفترة المذكورة بينت المتغيرات الصماء هي الاكثر كفاءة من تحويلات القوى في تحسين نموذج الانحدار لنسبة الاستهلاك الى الدخل القومي. ان المتغيرات الصماء ساعدت في تفسير 80% من نسبة الاستهلاك في الفترة المذكورة في العراق ذلك انها جعلت البيانات اكثر وضوحا وتجانسا في النموذج

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