Doctor of Philosophy

dissertationChirp signals arise in many applications of digital signal processing. In this dissertation, we address the problem of detection of chirp signals that are encountered in a bistatic radar which we are developing for remote sensing of cosmic ray induced air showers. The received echoes from the air showers are characterized by their large Doppler shift (several tens of MHz), and very short sweep period (~ 10 ^s). This makes our astrophysical problem a challenging one, since a very short sweep period is equivalent to a very low energy chirp signal. Furthermore, the related parameters of the received echoes are nondeterministic since they are tied to the physical parameters of the air showers that are stochastic in nature. In addition, our problem is characterized by the rarity of the expected chirp-echoes to be received, few events per week, and thus, background noise reception is the case most of the time. The primary focus of this research is to address these challenges and find an optimized detection approach under the existing receiver environment which contains non-Gaussian noise and is characterized by low signal-to-noise ratio (SNR). Matched filters are commonly used in radar systems when the chirp signal is known. In our first method, we revisit this context and use a matched filter as a basis of building a rake-like receiver that consists of a set of filters matched to quantized chirp rates, logarithmically distributed within the chirp-rate interval of interest. We examine the detection capability of the proposed structure through extensive theoretical and numerical analysis. Theoretical analysis and simulation results prove that the proposed detector has high detection capability for a range of chirp slopes in a low SNR environment. A major source of false-alarms was found to be due to sudden noise spikes that cover wide frequency bands. These transient signals have high amplitudes and occur at random time instants. This leads to erroneous detection decision. We study the influence of amplitude limiting the noisy signal on reducing the received false-alarms and enhancing the detection performance of the proposed rake-like receiver. In our second method, we use Hough transform (HT), which is widely used in the area of image processing for the purpose of finding parameterized patterns, as a basis of building a robust detection technique. We examine the detection capability of the proposed structure through theoretical and numerical analysis. Our results prove that the proposed detector has high detection capability for a range of chirp slopes in a low SNR environment. The introduced detection algorithms are implemented over a Virtex-5 FPGA. National Instruments modules are used as a high-performance custom hardware. Due to rarity of received echoes, we emulate the expected radar echoes to evaluate the system performance. The detection performance of the emulated echoes is examined using the implemented receiver at the field. Also, we compare the performance of both detectors

ゼブラフィッシュとインシリコ系を用いた、メラノーマにおけるニコチン-ニコチン性アセチルコリン受容体A1の機能解析と予後関連遺伝子の同定

内容の要約広島大学(Hiroshima University)博士(理学)Doctor of Sciencedoctora

Lactococcus lactis as a vector for oral vaccine delivery : the case of enterohemorrhagic Escherichia coli

In the present thesis we describe the utilization of the live vaccine delivery vector, L. lactis for the development of an oral vaccine against EHEC infection. The vaccine is based on the recombinant expression of the EHEC T3SS protein, EspB in L. lactis. The recombinant vaccine strains could successfully induce mucosal and systemic immune responses in mice upon oral immunization. These responses characterized by the presence of EspB-specific IgA antibodies in the feces and total Igs in the serum. Additionally, a mixed Th1/Th2 response was detected in Peyer’s patches and mesenteric lymph nodes. Furthermore, immunized mice showed protection against intestinal colonization by E. coli O157:H7 upon oral challenge. These findings demonstrate, for the first time, the potential of EspB as a candidate for oral vaccination against EHEC as well as the value of L. lactis as a vaccine delivery vector. The development of an oral vaccine based on the “GRAS” vector, L. lactis, can be particularly beneficial to infants and the elderly, which are the high risk groups for the complications of the hemolytic uremic syndrome. Additionally, the present thesis we address the issue of the gastrointestinal survival of L. lactis in pigs. We offer a proof of concept for the feasible use of aluminium hydroxide (bile acid binder) and camostat mesylate (oral trypsin inhibitor) in oral formulations of L. lactis-based vaccines to improve the gastrointestinal survival of the bacterium in pigs. This will particularly allow the validation of L. lactis-based vaccines in porcine models of infection, which are proven more reliable in the case of EHEC infection. Additionally, with consideration to the physiological similarities between pigs and humans, the application of these protectants can be extended to improve the gastrointestinal survival of L. lactis in humans

Preserved built heritage assessment as dead or living: An assessment study regarding built heritage safeguarding approaches in Erbil

Erbil city is recognized by its historical monuments. The citadel which is believed to be one of the oldest continuously inhabited civilized settlements was listed on UNESCO’s permanent World Heritage List (2014). A comprehensive preservation plan for the citadel was approved by the local authorities in 2006. This plan included recommendations for what was later called the Citadel's buffer zones. The buffer zone includes the traditional sectors of Erbil. Enormous efforts were done during the last decade by local authorities, UNESCO, NGOs, and local individuals. This study aims to assess and categorize preservation efforts implemented in these areas. The literature review diagnosed three main approaches for preservation that are followed in various parts of the world. These approaches can be categorized into two main approaches (dead and living heritage approaches). The preservation methods followed in the selected maintained structures within Erbil's traditional sectors were assessed by detecting 40 criteria that represent both approaches. The assessment was conducted through fieldwork in which 222 samples (vernacular and traditional buildings) were included. Statistical analysis depicted that the local authorities' approaches can be regarded as a dead heritage approach, while the recommended approach in the approved plan for the revitalization of Erbil Citadel and other traditional sectors can be regarded as a living heritage preservation approach. The paper recommends the living heritage preservation approach as a rescue from the at-risk status of built heritage structures of traditional sectors in Erbil city

ImageCaptioner2^2: Image Captioner for Image Captioning Bias Amplification Assessment

Most pre-trained learning systems are known to suffer from bias, which typically emerges from the data, the model, or both. Measuring and quantifying bias and its sources is a challenging task and has been extensively studied in image captioning. Despite the significant effort in this direction, we observed that existing metrics lack consistency in the inclusion of the visual signal. In this paper, we introduce a new bias assessment metric, dubbed $ImageCaptioner^2$, for image captioning. Instead of measuring the absolute bias in the model or the data, $ImageCaptioner^2$ pay more attention to the bias introduced by the model w.r.t the data bias, termed bias amplification. Unlike the existing methods, which only evaluate the image captioning algorithms based on the generated captions only, $ImageCaptioner^2$ incorporates the image while measuring the bias. In addition, we design a formulation for measuring the bias of generated captions as prompt-based image captioning instead of using language classifiers. Finally, we apply our $ImageCaptioner^2$ metric across 11 different image captioning architectures on three different datasets, i.e., MS-COCO caption dataset, Artemis V1, and Artemis V2, and on three different protected attributes, i.e., gender, race, and emotions. Consequently, we verify the effectiveness of our $ImageCaptioner^2$ metric by proposing AnonymousBench, which is a novel human evaluation paradigm for bias metrics. Our metric shows significant superiority over the recent bias metric; LIC, in terms of human alignment, where the correlation scores are 80% and 54% for our metric and LIC, respectively. The code is available at https://eslambakr.github.io/imagecaptioner2.github.io/

Financial Development and the Oil Curse: Evidence from Algeria

Most of the empirical evidence has shown that the majority of oil dependent countries have the low level of financial development; thus, they are much more volatile and exposed to the oil shocks and the so named “oil curse”. This paper aims to investigate the impact of the Algerian financial system—as one of major oil economies—on the economic growth and escaping the oil curse. Over the past two decades, Algeria has courageously attempted to modernize its financial system despite social strife and challenges posed by the large hydrocarbon sector and an inefficient public sector. In fact, various reforms have been undertaken since the early 1990s to the transition from planned to an open market economy. So, the first section provides the research background based on a theoretical model and a set of empirical studies about financial development and the oil curse. An analytical framework of the Algerian financial system evolution is provided in the second section, focusing on the two phases: 1990-1999 and 2000-2011. Finally, using an econometric growth regression model to test the impact of financial development in Algeria over the period 1980-2014, the preliminary results show that the financial development enhanced economic growth but it has not contributed in reducing the negative effect of oil rents

Effect of 1-methylcyclopropene (1-MCP) and waxing on quality and shelf-life of mango fruits

The effect of 1-methylcyclopropene (1-MCP) and waxing on quality and shelf-life of 'Kitchner' and 'Abu-Samaka' mango fruits was evaluated. The fruits were treated with 250 and 500 ppb of 1-MCP (SmartFresh, 0.14 %) with and without waxing. Food-grade wax was used for wax treatment and was applied in a thin layer by brushing over the surface of the fruits. After treatment, the fruits were packed in carton boxes and stored at 18 ± 1oC and 80-85 % relative humidity. Treatment by 1-MCP at 250 and 500 ppb significantly delayed fruit ripening and maintained quality of the two mango cultivars. The effect on fruit ripening was indicated by retarded respiratory climacteric, delayed peel color development, TSS accumulation and changes in titratable acidity, decreased fruit softening and weight loss, retained ascorbic acid content and maintained overall quality of the fruits. Fruit ripening was delayed by 4 and 7 days in fruits treated with 1-MCP at 250 and 500 ppb without waxing and by 6 and 9 days with waxing, respectively, compared with untreated fruits. Fruits treated with 1-MCP at 250 and 500 ppb with waxing resulted in 43.1 % and 55.1 % of fruits in the 'very good' quality grade and 21.3 % and 24.1 % in the 'good' grade, respectively, compared with only 22.3 % in the 'very good' grade and 13.6 % in the 'good' grade in the control fruits. On the other hand, only 11.5 % and 4.5 % of fruits were 'unmarketable' and 10.7 % and 6.5 % were in the 'poor' quality grade in fruits treated with 250 and 500 ppb with waxing, respectively, compared with 25.3 % of the fruits 'unmarketable' and 21.3 % in the 'poor' grade in the untreated fruits. قُـــوم تأثير معاملة الثمار بالميثايل سايكلوبروبين (1-MCP ) والتشميع على جودة وطول العمر التسويقي لثمار المانجو "كتشنر" و"أبوسمكة". عوملت الثمار بالميثايل سايكلوبروبين           ( (SmartFresh, 0.14% لمدة 24 ساعة على درجة حرارة 1 ± 18 °م فى حاويات بلاستيكية سعة 20 لتراً، وفقــاً لتوصيات الشركة المصنعة. تم الحصول على التركيزات المطلوبة من الميثايل سايكلوبروبين (1-MCP ) عن طريق إضافة25  ملى ليتر من الماء المقطر الدافئ في درجة حرارة 50 °م إلى الكميات المناسبة من مسحوق MCP ، حسبت وفقــاً لحجــم المساحة الحــرة، في  دوارق سعة 100 ملى ليتر. بعد الذوبان الكامل لمسحوق الميثايل سايكلوبروبين (1-MCP) وضعت الدوارق مع الثمار داخل الحاويات البلاستيكية وتم فتحها ثم أغلقت الحاويات على الفور لتجنب فقدان الغاز. كما وضعت الثمار غير المعاملة في حاويات مماثلة، ولكن بدون إضافة الميثايل سايكلوبروبين . (1-MCP) بعد 24 ساعة فتحت الحاويات وأخذت الثمار منها. إستخدم شمع من نوعية الشموع المجازة للمواد الغذائية فى طبقة رقيقة مسحت على أسطح الثمار، وفى حالة إستخدام المعاملتين معاً تمت المعاملة بالميثايل سايكلوبروبين (1-MCP) أولاً ثــم تلاها التشــميع. كانت المعامــلات (1) ثمـــار غيـر معاملة (شــاهد) و (2) ثمــار معاملة ب 250 جزء في البليون (1-MCP) و (3) ثمــار معاملة ب 500 جزء في البليون (1-MCP )  و(4)  ثمــار معاملة ب 250 جزء في البليون (1-MCP) مع التشــميع و (5) ثمــار معاملة ب 500 جزء في البليون (1-MCP ) مع التشــميع. من ثم تمت تعبئة الثمــار في صناديق كرتــون بأبعـــاد 15 × 33 × 43 سم وإســتخدم التصميم كامــل العشــوائية  بأربعــة مكــررات لإجــراء التجربة، وحفظت الثمــار على درجة حرارة 18 ± 1 °م ورطــوبة نســبية  80 % - 85 %. أدت معاملة ثمـــار المانجــو بمــادة الميثايل سايكلوبروبين (1-MCP) بتركيز  250 و500 جــزء في البليـــون إلى تأخيــر معنــوى فى نضــج الثمــارفى صنفى ثمــار المانجـــو. أدت المعاملة بمادة الميثايل سايكلوبروبين (1-MCP) مع التشـميع إلى تأخيــر أكثــر فى النضــج وفى المحافظــة جــودة الثمـــار. إنعكس تأثير المعاملة فى تأخيــر وصــول الثمـــار إلى ذروة التنفس وتلــون القشــرة وتراكــم المــواد الصلبة الذائبة فيها وليــونة الثمـــار والتغيــرات في الحموضة وفقـــدان الوزن والحفــاظ على محتـــوى حمض الأســـكوربيك والمحافظة على جــودة الثمـــار. أدت المعاملة بالميثايل سايكلوبروبين (1-MCP) بتركيز 250 و500 جزء فى البليــون بدون تشــميع إلى تأخيــر نضــج الثمــار لفتــرة 4 و 7 أيام، كما أدت المعاملة بالميثايل سايكلوبروبين بتركيز 250 و500  جــزء في البليـــون مع التشــميع إلى تأخيــر النضــج لفتــرة 6 و 9 أيام، على التوالي، مقارنة مع الثمــار غير المعاملة. نتــج عن المعاملة ب 250 و500 جزء في البليون من الميثايل سايكلوبروبين (1-MCP) مع التشــميع أن 43.1  % و55.1 % من الثمــار كانت في درجة الجــودة "جيــد جــداً" و 21.3 ٪ و 24.1 % من الثمـــار  في درجة "جيــد"، على التوالى، مقارنة ب 22.3 % من الثمار في درجة "جيد جداً" و 13.6 % في درجة "جيــد" فى الثمــار غير المعاملة. من ناحية أخرى، فإن 11.5 % و 4.5 % فقط من الثمـــار كانت في درجـــة "غير القابلة للتســويق" و 10.7 % و6.5 % من ثمـــار"رديئة" في الجـــودة من الثمــــار المعاملة بالميثايل سايكلوبروبين بتركيز 250 و500 جزء في البليـــون مع التشميع، على التوالي، مقارنة ب 25.3 % من الثمــــار "غير القابلة للتسويق" و21.3 % من الثمـــار "الرديئة" في الثمـــارغير المعاملة. &nbsp

PKCAM: Previous Knowledge Channel Attention Module

Recently, attention mechanisms have been explored with ConvNets, both across the spatial and channel dimensions. However, from our knowledge, all the existing methods devote the attention modules to capture local interactions from a uni-scale. In this paper, we propose a Previous Knowledge Channel Attention Module(PKCAM), that captures channel-wise relations across different layers to model the global context. Our proposed module PKCAM is easily integrated into any feed-forward CNN architectures and trained in an end-to-end fashion with a negligible footprint due to its lightweight property. We validate our novel architecture through extensive experiments on image classification and object detection tasks with different backbones. Our experiments show consistent improvements in performances against their counterparts. Our code is published at https://github.com/eslambakr/EMCA