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Robust Outlier Detection Techniques for Skewed Distributions and Applications to Real Data

Thesis Info

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External Link

Author

Iftikhar Hussain Adil

Program

PhD

Institute

International Islamic University

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2011

Thesis Completion Status

Completed

Subject

Islamic economics

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1810

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725334556

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Most of the data sets belonging to the real world contain observations at the extremes that might not be in conformity with the remaining data set. These extreme observations known to be outliers might have positive or negative effect on the data analysis like regression estimates, forecasting and ANOVA etc. Outliers are powerful tools to identify the most interesting events of the world in cross sectional data and historically important events can be picked by detecting outliers in time series data sets. Numerous outlier detection techniques have been proposed in the literature. This study provides a survey of these techniques and their properties. Most of these techniques work well under the assumption that data come from a symmetric distribution and these techniques fail to work in skewed distributions. Because of this limitation, Hubert and Vandervieren (2008) proposed a technique for outlier‟s detection in skewed data sets. Our thesis presents a new technique to measure robust skewness (SSS) and a new outlier detection technique (SSSBB) for skewed data distributions. The study shows that the proposed technique measures skewness more accurately than existing techniques and the proposed technique for outlier‟s detections works better than Hubert‟s technique on a class of theoretically skewed and symmetric distributions. The study also compares the technique with other established outlier detection techniques in the literature. This study uses simulation technique for computer generated distributions and some real data sets for comparison purposes. The study also analyzes real life data sets and compares the baby birth weight data and stock returns, both of which are known to be skewed. These results will help us in making a choice of appropriate outlier detection technique for skewed data sets for different sample sizes which might be helpful in identifying underweight babies.
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خطۂ سیالکوٹ میں اردو شاعری کی روایت

سیالکوٹ ایک تاریخی اور ادبی خطہ  رہا ہے۔ اس کی تاریخ پانچ ہزار سال پر محیط ہے۔یہ خطہ  جغرافیائی لحاظ سے اس مقام پر واقع ہے جہاں کئی آبی گذرگاہیں ہیں۔ کشمیر اور پنجاب کے دیگر تجارتی شہروں سے اس کا قریبی رابطہ ہے۔ سیالکوٹ تاریخی، ثقافتی، سماجی، تہذیبی، علمی اور ادبی لحاظ سے لاہور اور دوسرے ادبی، ثقافتی، تہذیبی، تاریخی اور علمی شہروں سے کسی طور پر بھی کم نہیں۔ اس شہر کی ثقافت توانائی اور رنگا رنگی لیے ہوئے ہے۔ یہاں کے میلے ٹھیلے، روایتی تہوار اور دیگر ثقافتی سرگرمیاں اس  خطے  کو  ہمیشہ ممتاز کرتی رہی ہیں۔ 

سیالکوٹ کو اقبال و فیض کے مولد ہونے کا  لا زوال فخر حاصل ہے۔  یہ ایک صنعتی شہر ہے ۔اس کی آبادی  تقریباً تیس  لاکھ سے  زیادہ نفوس پر مشتمل ہے سر زمین  سیالکوٹ صدیوں  کی انسانی تہذیب و تمدن اور ادب و ثقافت کا عظیم الشان گہوارہ ہے۔ اس دھرتی کے تاریخی آثار  مدت سے مورخین و ماہرین آثار قدیمہ کی دلچسپی کا سامان بھی رہے ہیں۔ یہاں کی تہذیب ٹیکسلا اور موہنجو ڈارو کی تہذیبوں کے ہم پلہ ہے۔

   سیالکوٹ  کی مٹی بڑی زرخیز اور مردم خیز ہے۔سرزمین سیالکوٹ نے علم و ادب اور فنون لطیفہ  کے  میدانوں میں گراں قدر خدمات سرانجام دی ہیں۔ اس خطے کے باشندوں  نے پاکستان کی صنعتی  و اقتصادی ترقی کے ساتھ ساتھ علم و فن کی خدمت بھی جاری رکھی۔ ماضی میں ملا کمال کشمیری، ملا عبدالحکیم  سیالکوٹی،  امین حزیں سیالکوٹی، اثر صہبائی، مرزا ریاض  اور غلام الثقلین نقوی نے علمی وادبی  حوالے سے سیالکوٹ کا نام روشن کیا۔ مولوی میر حسن، مولوی ابراہیم  میر، ڈاکٹر جمشید راٹھور اور یوسف سلیم چشتی نے علم کی پیاس بجھائی۔ڈاکٹر  وحیدقریشی سیالکوٹ کے ادبی ماحول کے بارے میں رقمطراز ہیں۔

”دینی...

جنین کا عصری اور شرعی تناظر میں تحقیقی جائزہ

Allah (SWT) dignified human beings among all the creatures and made these (creatures) all subjugated to men. Allah says in the Holy Qur’ān: (He is such a Lord who has created all the things in the universe for you). The beginning of human generation is traced back to the miraculous birth of Adam (A.S), and Allah entrusted their survival in their physical bodies in the process of fusing the male and female gametes in the womb of mother. And new offspring are born undergoing many developmental stages. The Holy Qur’ān has mentioned all the stages of the human being like: its creation started from dust, then from seamen, then a clot, then from a flesh (Al- Qur’ān, 22: 5). The same are described by modern medical sciences. The medical sciences also describes it in details that how a “fetus” is created and the process which it passes through. This article discusses how the “Fetus” is described in Islamic Sources, modern medical sciences and what are the similarities between these two?

Phytochemical, Pharmacognostic and Pharmacological Investigations of Tylophora Wall and Onosma Griffthii Vatke

Northern regions of Pakistan are rich with medicinal plants that are yet to be explored on scientific grounds. Medicinal plants play vital role in a country’s economy; especially for a country like Pakistan, where people are very poor and the use of traditional medicine is yet to flourish. World Health Organization is giving more emphasis on promoting traditional medicine, particularly, in the Third World Countries. More than 8,000 plant species in South Asia have medicinal values; out of which 2000 medicinal plants exists in Pakistan. Global market of the medicinal plants is estimated over US$ 60.0 billion that is expected to grow upto the US$ 5.0 trillion by the year 2050. In Pakistan, bill on the import of medicinal plants was worth of US$ 31.0 million, where the export of medicinal plants could hardly reached US$ 6.0 million. In the world, thirty percent of the pharmaceutical preparations are manufactured from plants. Keeping in view the potential of the global and local market, we conducted our current research work entitled “phytochemical, pharmacognostic and pharmacological investigations of Tylophora hirsuta (Wall) and Onosma griffithii (Vatke)”. The present Ph.D thesis comprises of two parts, part A and part B. The part A describes extraction, isolation and structure elucidation of isolated compounds. Pharmacological and biological activities of crude extract, different fractions thereof and some compounds isolated from Tylophora hirsuta have been investigated. In addition, the plant was also subjected to pharmacognostic screening that describes the anatomical study of the aerial parts and its powder drug. Four compounds were isolated from fractions of crude methanolic extract of the aerial parts of Tylophora hirsuta. α-amyrin acetate (1), stigmasterol (2) and heptaeicosanol (4) were isolated for the first time from the plant. β- sitosterol (3), a previously reported compound from the same plant was also isolated. Crude methanolic extract, its fractions and major compound (1) were investigated for various pharmacological activities including spasmolytic, spasmogenic, calcium channel blocking and cardiovascular activities. In addition, certain biological investigations were also carried out including antileishmanial, brine-shrimp lethality, phytotoxic, insecticidal and enzyme inhibition assays. The plant produced good spasmogenic, spasmolytic and calcium channel blocking activity. The major compound (1) also displayed significant spasmolytic activity at concentration of 53.1 x 10 -5 - 243 x 10 -5 M. Biological investigations revealed that the plant has good antileishmanial, and moderate insecticidal, antibacterial, antifungal and phytotoxic activities. However, no significant enzyme inhibition assay was displayed by the major compound (1). Anatomical study of stem portion showed a typical dicotyledonous stem with well organized vascular bundle and trichomes on the outer surface. Powder drug study of the plant also supported the anatomical observations with presence of trichomes, calcium oxalate crystals, starch cells and other structures. Part B describes the phytochemistry of compounds 5, 6 and 7 that have been isolated for the first time from the Onosma griffithii. The preliminary phytochemical investigations revealed the presence of flavonoids and terpenes in Onosma griffithii. The anatomical study of the leaf reveals the presence of oil sacs in the lamina. Powder drug study of the plant also supported the anatomical observations with strong trichomes, stoma surrounded by guard cells for the transport of gases and water, epidermis and other structures. Crude methanolic extract was investigated for different pharmacological activities like spasmogenic, spasmolytic and effects on cardiovascular system. Crude methanolic extract and its different fractions were investigated for certain biological activities including antileishmanial, antibacterial, antifungal, brine-shrimp lethality, phytotoxic and insecticidal activities. The plant was found to possess excellent spasmolytic and antihypertensive activity that confirmed its traditional use as antihypertensive. Biological investigations revealed that the plant has significant antileishmanial and moderate antifungal activity. Our current work will help the researchers for further work to standardize the extract(s) and look for activity guided isolation of the pharmacologically / biologically active compounds.