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2020

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Articles 14701 - 14730 of 14752

Full-Text Articles in Physical Sciences and Mathematics

Stratigraphy And Volcanic Facies In Khao Noi Area, Tha Takiap District, Chachoengsao Province, Amporn Chaikam Jan 2020

Stratigraphy And Volcanic Facies In Khao Noi Area, Tha Takiap District, Chachoengsao Province, Amporn Chaikam

Chulalongkorn University Theses and Dissertations (Chula ETD)

The Khao Noi volcanics is in Tha Takiap district, Chachoengsao province, eastern Thailand. This volcanics is a part of the Lampang volcanic belt, a potential host rocks for mineralizations, especially gold and antimony epithermal style deposits. Based on field investigation, drill core logging, and petrographic study, the Khao Noi host volcanic sequence has a thickness of at least 150 meters. The sequence can be divided into three units, namely 1) Sedimentary unit (Unit 1), 2) Mafic-intermediate volcanic unit (Unit 2), and 3) Felsic volcanic unit (Unit 3). Unit 1 forms as a basement of the Khao Noi volcanic sequence and …

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Removal Of Arsenic From Wastewater Using Mixed Metal Hydroxides And Biopolymers, Angchuda Ratroj Jan 2020

Removal Of Arsenic From Wastewater Using Mixed Metal Hydroxides And Biopolymers, Angchuda Ratroj

Chulalongkorn University Theses and Dissertations (Chula ETD)

Arsenic is one of the contaminants in wastewater which becomes a worldwide environmental problem. Therefore, several simple and cost-effective techniques have been developed for arsenic removal. This study reports on the removal of arsenic by coprecipitation method with variable combinations of the well-known metal salts, such as FeCl3 or AlCl3 with the environmentally friendly inorganic metal salts, such as MgCl2 or CaCl2, which is called "mixed metal system". Moreover, for improving the low toxicity from sludge production, hence the coprecipitation techniques using mixed metal salts as coagulants combine with biopolymers (alginate or chitosan) as flocculants for arsenic removal were also …

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Multi-Evidence Learning For Medical Diagnosis, Tongjai Yampaka Jan 2020

Multi-Evidence Learning For Medical Diagnosis, Tongjai Yampaka

Chulalongkorn University Theses and Dissertations (Chula ETD)

In recent years, a great many approaches for learning from multiple sources by considering the diversity of different views have been proposed. The most interesting field is medical diagnosis. For example, breast cancer screening normally employs two views of mammography (Cranio-Caudal and Medio-Lateral-Oblique) or two modes of ultrasound (B-mode and Doppler mode) breast images. This study proposes a multi-evidence learning model that combines the multiple evidences of breast images to improve diagnosis. Two views mammography and two modes of ultrasound were used. Our proposed model consists of four stages. First, feature extraction using Convolutional Neuron Networks was operated to extract …

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Development Of Graphite-Based Conductive Patterns By Copper Electroless Plating And Electroplating Techniques, Vipada Aupama Jan 2020

Development Of Graphite-Based Conductive Patterns By Copper Electroless Plating And Electroplating Techniques, Vipada Aupama

Chulalongkorn University Theses and Dissertations (Chula ETD)

The screen-printing technique has been widely applied in electronic manufacturing field. In this work, graphite is used for fabricating conductive patterns by screen-printing technique. Moreover, enhance the performance of electrical conductivity by electroless plating and electroplating techniques. The study was separated into two parts. Firstly, optimize the mass ratio between graphite and polyvinylidene fluoride (PVDF). In prepared ink from varied mass ratio; 2.0:0.1, 2:0.2, and 2:0.3 respectively. Volume resistivity analysis of conductive patterns, it was found that the mass ratio between graphite and PVDF of 2: 0.2 provided the lowest volume resistivity of 0.0122 Ω-m. In other cases, the mass …

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Study Of Interactions Between Magnesium Silicate Particle And Diamond-Like Carbon Using Atomic Force Microscopy, Vipada Dokmai Jan 2020

Study Of Interactions Between Magnesium Silicate Particle And Diamond-Like Carbon Using Atomic Force Microscopy, Vipada Dokmai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Interaction between particles and different surfaces under ambient condition is studied using AFM-based force spectroscopy. This work focuses on the adhesion mechanism and factors affecting particle-surface adhesion. The particles of interest consist of magnesium silicate (talcum powder) and zinc oxide (ZnO) particles, which have very attractive properties and are widely used in several applications. The adhesion force measurements were first carried out using silicon/silicon coated with DLC probes pressed on talc particles modified with hydrochloric acid or different organosilanes. These modifications change hydrophobicity and hydrophilicity of the particles. The results show that the adhesion forces are distributed in a bimodal …

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Artificial Intelligence And Copyright Law In Singapore A Study On The Protection Of Compilations And Databases Arranged By Ai-Systems, Sella Say Jan 2020

Artificial Intelligence And Copyright Law In Singapore A Study On The Protection Of Compilations And Databases Arranged By Ai-Systems, Sella Say

Chulalongkorn University Theses and Dissertations (Chula ETD)

While the capability of artificial intelligence ("AI") gains remarkable momentum in creating copyrightable materials – the questions regarding the eligibility of these new creations, at the moment, are broadly discussed and posed challenges to the regime. The problem of how we fit the conventional notion of authorship and the condition of originality for AI-generated works remains a controversial topic. Some might suggest that subject matter created by AI should not be granted copyright protection on the presumption that AI is not a human who could treat as authors of works. At the same time, other supportive claims that the first …

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Quaternion Algebras Over Some Extensions Of Function Fields, Silipong Thongmeepun Jan 2020

Quaternion Algebras Over Some Extensions Of Function Fields, Silipong Thongmeepun

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this thesis, we study quaternion algebras over rational function fields over finite fields of odd order. [It is known that a quaternion algebra is either the algebra of 2x2- matrices or a division algebra.] We determine conditions for quaternion algebras of the form(symbol) to be division algebras and conditions for quaternion algebras to split after the constant quadratic field extension.

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Conversion Of N-Pentane To Light Olefins Over Modified Zr/Hzsm-5-Based Catalysts, Bharanabha Makkaroon Jan 2020

Conversion Of N-Pentane To Light Olefins Over Modified Zr/Hzsm-5-Based Catalysts, Bharanabha Makkaroon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Ethylene and propylene are important raw materials for producing several types of chemicals and polymers. According to the increase of propylene demand in recent year, the P/E ratio was increased to 0.85. In order to meet the propylene demand, the development of hybrid HZSM-5 catalyst for catalytic cracking becomes more interesting owing to the cracking activity from HZSM-5 zeolite acid site and loaded metal on HZSM-5 that expected to promote the dehydrogenation activity to the catalyst which could possibly enhanced the P/E ratio. The alternative feedstock for this process is n-pentane which is the low-value product from distillation process. The …

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Influence Of Mixed Anionic-Nonionic Surfactants On Methane Hydrate Formation : Suppression Of Foam Formation, Chakorn Viriyakul Jan 2020

Influence Of Mixed Anionic-Nonionic Surfactants On Methane Hydrate Formation : Suppression Of Foam Formation, Chakorn Viriyakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Solidified natural gas (SNG) via clathrate hydrate is a new technology for natural gas storage with high energy content per unit volume, extremely safe, and ease to recover. Although SNG has several advantages, its limitation is low rate of hydrate formation. Sodium dodecyl sulfate (SDS) is well known as a kinetic promoter used to increase the hydrate formation rate. However, using SDS resulted in a large amount of foam during gas recovery. In order to alleviate this problem, mixtures of SDS with nonionic surfactants were investigated. Polyoxyethylene (n) lauryl ether (EO₃ and EO₅) and alkyl poly glycol (APG) were mixed …

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Layer-By-Layer Surface Modification Of Polymer Filament For Catalytic 3d Printed Parts, Pornnutcha Thadasri Jan 2020

Layer-By-Layer Surface Modification Of Polymer Filament For Catalytic 3d Printed Parts, Pornnutcha Thadasri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Catalyst was constructed in form of microreactor by fused deposition modeling (FDM) or 3D printing method that allow micro scale customization in order to achieve high detail construction. Poly (lactic acid) (PLA) and Poly (acrylonitrile-butadiene-styrene) (ABS) filaments were used as a built-up material. The surface modification was introduced to improve filaments surface adhesion by using alkaline treatment and Polyethyleneimine with variation of time and concentration and then deposited with polyelectrolyte multilayers by layer-bylayer technique before catalyst loading. Catalyst were synthesized by reduction reaction of Silver nitrate (AgNO₃) and sodium borohydride (NaBH4) with using poly (4-styrenesulfonic acid-co-maleic acid) as a capping …

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Pyrrolidine As A Promoter For Methane Hydrate Formation: Comparative Study On The Thermodynamics, Kinetics, And Morphology With Tetrahydrofuran, Siravich Junthong Jan 2020

Pyrrolidine As A Promoter For Methane Hydrate Formation: Comparative Study On The Thermodynamics, Kinetics, And Morphology With Tetrahydrofuran, Siravich Junthong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Solidified natural gas (SNG) via clathrate hydrates has been proposed as an alternative approach for natural gas storage and transportation due to its numerous advantages. However, a slow hydrate formation rate and a requirement of operating conditions are the major limitations, which need to be improved to make SNG competitive in a large scale deployment. In this work, the roles of 5.56 mol% pyrrolidine were investigated for the methane hydrate formation in terms of thermodynamics and kinetics along with morphology. The results showed that pyrrolidine generally improved the thermodynamic stability of mixed methane hydrates, enhancing the formation at milder conditions …

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Solid-Liquid-Polymer Mixed Matrix Membranes For Gas Separation: Silicone Rubber Membranes Filled With Nax And Ky Zeolites Adsorbed Peg, Sitthikiat Boonchoo Jan 2020

Solid-Liquid-Polymer Mixed Matrix Membranes For Gas Separation: Silicone Rubber Membranes Filled With Nax And Ky Zeolites Adsorbed Peg, Sitthikiat Boonchoo

Chulalongkorn University Theses and Dissertations (Chula ETD)

Carbon dioxide (CO₂) is one of the major constituents of natural gas and biogas. The presence of high CO₂ content causes some serious problems including reduction of heating value and corrosion of equipment's surface. Additionally, CO₂ emission is the main issue of the greenhouse effect. In consequence of these problems, membrane technologies have drawn much attention as potential techniques for gas separation. mixed matrix membranes (MMMs) have been studied and developed to provide the synergistic effect of inorganic and organic materials on membranes. In this study, PEG/NaX:KY/SR mixed matrix membranes (PZS MMMs) were prepared by the solution casting method using …

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Identification Of Crude Palm Oils By The Analyses Of Fatty Acids, Volatile Organic Compounds, And Carotenoids, Somluk Sanorkham Jan 2020

Identification Of Crude Palm Oils By The Analyses Of Fatty Acids, Volatile Organic Compounds, And Carotenoids, Somluk Sanorkham

Chulalongkorn University Theses and Dissertations (Chula ETD)

An in-depth analysis of crude palm oil is important to differentiate crude palm oil (CPO) from different geographic provenance for administrative control purposes to prevent and solve the problem of smuggling CPO from abroad to Thailand. In this study, eleven CPO samples from five provinces in Thailand were studied for their composition. The compositions of fatty acids, volatile organic compounds (VOCs), and carotenoids were characterized by GC-FID, GC-MS, and HPLC-DAD techniques, respectively. The chromatograms of fatty acids distribution were similar for all samples. The main components of fatty acids are palmitic acid, oleic acid, linoleic acid, and stearic acid. In …

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Silver Surface Enrichment On Zsm-5 Zeolites For The Catalytic Cracking Of N-Pentane To Produce Light Olefins, Warisara Angguravanich Jan 2020

Silver Surface Enrichment On Zsm-5 Zeolites For The Catalytic Cracking Of N-Pentane To Produce Light Olefins, Warisara Angguravanich

Chulalongkorn University Theses and Dissertations (Chula ETD)

The effects of Ag-incorporation on the catalytic performance of ZSM-5 zeolites have been investigated. Since Ag-incorporation can promote the formation of light olefins and significantly enhance catalytic performance in n-pentane catalytic cracking. However, the Ag-incorporated ZSM-5 zeolite was rapidly deactivated in npentane catalytic cracking. Thus, CLD and sulfation methods were introduced to improve catalytic activity and stability of Ag-incorporated ZSM-5 zeolites. The Agincorporated ZSM-5 zeolites have been prepared by the incipient wetness impregnation and CLD methods. Moreover, the sulfated catalyst was prepared by the sequential CLD and sulfation of commercial HZSM-5 zeolite. The catalytic activity and stability of Ag-incorporated ZSM-5 …

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กลูโคสไบโอเซ็นเซอร์แบบไม่ใช้เอนไซม์จากคอปเปอร์ออกไซด์/รีดิวซ์กราฟีนออกไซด์นาโนคอมพอสิต, นพรัตน์ จันทร์มี Jan 2020

กลูโคสไบโอเซ็นเซอร์แบบไม่ใช้เอนไซม์จากคอปเปอร์ออกไซด์/รีดิวซ์กราฟีนออกไซด์นาโนคอมพอสิต, นพรัตน์ จันทร์มี

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในงานวิจัยนี้กลูโคสไบโอเซ็นเซอร์แบบไม่ใช้เอนไซม์ถูกพัฒนาขึ้นโดยใช้นาโนคอมพอสิตของโลหะออกไซด์และรีดิวซ์กราฟีนออกไซด์ ขั้วไฟฟ้าคาร์บอนพิมพ์สกรีนถูกดัดแปรด้วยรีดิวซ์ กราฟีนออกไซด์เพื่อเพิ่มการนำไฟฟ้าและดัดแปรด้วยโลหะออกไซด์ที่มีขนาดในระดับนาโนสองชนิด ได้แก่ คอปเปอร์ออกไซด์ และซิงค์ออกไซด์เพื่อเป็นตัวเร่งทางเคมีไฟฟ้าสำหรับการเกิดออกซิเดชันโดยตรงของกลูโคส โดยศึกษาความเข้มข้นของสารดัดแปรที่เหมาะสมด้วยกล้องจุลทรรศน์อิเล็กตรอนแบบส่องกราด จากนั้นเปรียบเทียบประสิทธิภาพการเร่งปฏิกิริยาของขั้วไฟฟ้าดัดแปรด้วยโลหะออกไซด์ด้วยเทคนิคไซคลิกโวล แทมเมทรีพบว่าขั้วไฟฟ้าคาร์บอนพิมพ์สกรีนที่ถูกดัดแปรด้วยรีดิวซ์กราฟีนออกไซด์และคอปเปอร์ออกไซด์ให้กระแสสูงสุด จึงเลือกมาใช้เป็นขั้วไฟฟ้าสำหรับกลูโคสไบโอเซ็นเซอร์แบบไม่ใช้เอนไซม์ สำหรับการตรวจวัดกลูโคสในตัวอย่างจริง อุปกรณ์รูปแบบใหม่ถูกสร้างขึ้นโดยติดกระดาษพิมพ์แวกซ์ที่เคลือบด้วยโซเดียมไฮดรอกไซด์เพื่อเป็นส่วนป้อนสารตัวอย่างลงบนขั้วไฟฟ้าคาร์บอนพิมพ์สกรีนที่ถูกดัดแปรด้วย รีดิวซ์กราฟีนออกไซด์และคอปเปอร์ออกไซด์ อุปกรณ์นี้ถูกใช้ตรวจวัดกลูโคสในฟอสเฟตบับเฟอร์ซาลีนแสดงช่วงความเป็นเส้นตรงที่ 0.125 ถึง 7.0 มิลลิโมลาร์ และ 0.031 ถึง 7.0 มิลลิโมลาร์ โดยมีค่าสัมประสิทธิ์สหสัมพันธ์ที่ 0.9940 และ 0.9911 สำหรับการตรวจวัดด้วยเทคนิคไซคลิกโวลแทมเมทรีและเทคนิคแอมเพอโรเมทรี ตามลำดับ นอกจากนี้ขั้วไฟฟ้าคาร์บอนพิมพ์สกรีนที่ถูกดัดแปรด้วยรีดิวซ์กราฟีนออกไซด์และคอปเปอร์ออกไซด์สามารถคงประสิทธิภาพการตรวจวัดได้ถึง 6 วันภายหลังการเตรียมอุปกรณ์ กลูโคสไบโอเซ็นเซอร์แบบไม่ใช้เอนไซม์ที่พัฒนาขึ้นนี้จึงสามารถประยุกต์เป็นอุปกรณ์ทางเลือกสำหรับติดตามผู้ป่วยโรคเบาหวานอย่างง่ายโดยไม่ต้องเตรียมตัวอย่าง

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The Effect Of Wildlife Wellbeing On Environmental Concern, Laura Casne Jan 2020

The Effect Of Wildlife Wellbeing On Environmental Concern, Laura Casne

Department of Environmental Studies: Undergraduate Student Theses

Environmental campaigns have used animal imagery to push their initiatives for years, shocking viewers with images of human caused damage to change environmental behavior. The Royal Society for the Prevention of Cruelty to Animals (RSPCA), a nonprofit located in Britain released a statement that they responded to 5000 calls annually regarding litter and that the main victims were wildlife species (Litter and Animals | Rubbish and Animals - RSPCA, 2017). A previous study done by Schultz (2000) showed animals in different conditions (animals in nature and animals harmed in nature), with results indicated that those who viewed an image of …

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Ecological Perspectives Of The Eastern Saline Wetlands Differ Between Visitors And Non-Visitors, Peter Janda Jan 2020

Ecological Perspectives Of The Eastern Saline Wetlands Differ Between Visitors And Non-Visitors, Peter Janda

Department of Environmental Studies: Undergraduate Student Theses

The Eastern Saline Wetlands of Nebraska can be found in both Lancaster and Saunders counties in Eastern Nebraska. Due to the wetlands’ important services in the areas of recreation, wildlife habitat, and flood control, it is necessary to know the extent to which these services are valued and used by residents of Lincoln . Past research completed in 2015 by the Lower Platte South NRD observed public opinions toward wetland restoration and preservation, finding that 46% of the public strongly support it, 35% mildly support it and 16% do not support it (Saline Wetlands Conservation Partnership, 2006). This past study …

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The Changing Habitat And Decline Of Ring-Necked Pheasant Populations In Otoe County, Nebraska, Jacob T. Herman Jan 2020

The Changing Habitat And Decline Of Ring-Necked Pheasant Populations In Otoe County, Nebraska, Jacob T. Herman

Department of Environmental Studies: Undergraduate Student Theses

Since the early 20th century, wildlife conservation in Untied States has walked a fine line of growth and decline. The implementation of the Ring-Necked Pheasant in Nebraska has brought a wealth of tradition and revenue to the state across multiple generations. This thesis analyzes how habitat changes in Otoe County, Nebraska have affected the Ring-Necked Pheasant population, and what programs are in place to counteract the issue. To answer this question, the study compared five different aerial photos taken from Google Earth Pro and the county archives located in Hardin Hall at the University of Nebraska- Lincoln. The results of …

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Incorporating Tallgrass Prairie Into Urban Environments, Daniel Hauschild Jan 2020

Incorporating Tallgrass Prairie Into Urban Environments, Daniel Hauschild

Department of Environmental Studies: Undergraduate Student Theses

As an agricultural state with a population poised to shift to primarily urban based, Nebraska is in the unique position of being able to decide how people live in modern cities. While the benefits of including green spaces in urban areas are well documented, evidence also suggests that increased biodiversity in these areas compounds those benefits. As such, incorporating elements of functioning natural ecosystems within urban areas can potentially create pockets of sustainable landscapes. Nebraska’s two largest population centers are located on land that was historically tallgrass prairie, an iconic landscape in American history and now almost entirely absent from …

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Growth And Feeding Response In Python Regius In Ambient Temperature Vs. Hot-Spot, Mckenzie Martinez Jan 2020

Growth And Feeding Response In Python Regius In Ambient Temperature Vs. Hot-Spot, Mckenzie Martinez

Department of Environmental Studies: Undergraduate Student Theses

Python regius, also known as the ball python or the royal python, is one of the most popular reptiles in the pet trade and has been heavily imported, kept, and bred in captivity since 1976 (Toudonou 1). This species has adapted to life in captivity extremely well making it one of the most popular reptiles in the reptile trade. It is one of the first reptiles many reptile enthusiasts own. It is a frequently used species for educating the public in zoos and other facilities. Some of the main reasons that Python regius has maintained its popularity in the reptile …

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The Effects Of Street Tree Site Planting Width On Canopy Width And Ability To Provide Ecosystem Services, Ryan Kendall Jan 2020

The Effects Of Street Tree Site Planting Width On Canopy Width And Ability To Provide Ecosystem Services, Ryan Kendall

Department of Environmental Studies: Undergraduate Student Theses

In a time where pests such as emerald ash borer are reducing urban forests, it is important to gain a return on investment for new trees planted. Since trees cost money, the value of the ecosystem services that they provide over the course of their lives should outweigh their costs. Due to the need for a return on investment, it is important to know whether newly planted street trees are being planted in a space that does not inhibit their growth or ability to provide benefits. This study, in Lincoln, NE looks to determine the relationship between a street tree’s …

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The Effect Of Pictorial Signs On Recycling Rates, Christopher A. Sukstorf Jan 2020

The Effect Of Pictorial Signs On Recycling Rates, Christopher A. Sukstorf

Department of Environmental Studies: Undergraduate Student Theses

Recycling is a core way that college students can act altruistically. Many studies have been conducted to study how to increase the participation of recycling on college campuses, office buildings, and the like. This study focuses on the University Lutheran Chapel, a Christian church adjacent to the University of Nebraska – Lincoln. While the University of Nebraska – Lincoln has drastically improved recycling participation in recent years, the University Lutheran Chapel lags behind. Pictorial signs were used in an experiment to determine whether they improved recycling rates at The Chapel. Recycling rates at the University Lutheran Chapel were measured by …

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Planning Urban Forests In A Changing Climate, Ethan Dudden Jan 2020

Planning Urban Forests In A Changing Climate, Ethan Dudden

Department of Environmental Studies: Undergraduate Student Theses

As the effects of negative effects of climate change are realized, urban forests a means to reduce the potential damage and adverse conditions in urban areas (Wolf, et al., 2020) (Livesley, McPherson, & Calfapietra, 2016) (Xiao & McPherson, 2002). Preserving these resources is becoming more difficult however, as the trees that make up urban landscapes become less adapted to current conditions with every passing year (Aitken, Yeaman, Holliday, Wang, & Sierra, 2008). Changes in climate and world systems also point to invasive pests becoming greater threats to urban forest resources with time (Tubby & Webber, 2010) (Amberger et al., 2017). …

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Future Implications Of Extreme Heat On Public Health For Those Living In Lincoln, Nebraska, Mandy Koehler Jan 2020

Future Implications Of Extreme Heat On Public Health For Those Living In Lincoln, Nebraska, Mandy Koehler

Department of Environmental Studies: Undergraduate Student Theses

Increasing temperatures are expected as the climate crisis progresses. This crisis is fueled by the increasing amount of greenhouse gas emissions being released into the atmosphere, which trap heat in the environment. With rising temperatures, more extreme heat events threaten multiple sectors of society including public health. To gain insight into future climate issues related to warming temperatures and public health for people living in Lincoln, Nebraska, this research will evaluate the predicted extent of extreme heat for this area and consider what other relevant regions do to deal with these problems. This study identifies the scope of future extreme …

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To What Extent Has The Relationship Between Humans And Red Foxes (Vulpes Vulpes) Evolved Throughout History?, Abigail Misfeldt Jan 2020

To What Extent Has The Relationship Between Humans And Red Foxes (Vulpes Vulpes) Evolved Throughout History?, Abigail Misfeldt

Department of Environmental Studies: Undergraduate Student Theses

Red foxes are one of the few creatures able to adapt to living alongside humans as we have evolved. All humans and wildlife have some id of relationship, be it a friendly one or one of mutual hatred, or simply a neutral one. Through a systematic research review of legends, books, and journal articles, I mapped how humans and foxes have evolved together. First, the relationship between humans and foxes in a geographical manner by starting in Asia, moving to Australia and Tasmania, then Europe, Africa, finishing with North and South America. I will be analyzing all the information through …

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A Robust System For Core Thai Natural Language Processing Technologies, Can Udomcharoenchaikit Jan 2020

A Robust System For Core Thai Natural Language Processing Technologies, Can Udomcharoenchaikit

Chulalongkorn University Theses and Dissertations (Chula ETD)

As the amount of unstructured textual data grows, it becomes increasingly important to build an intelligent system that can process it. Natural Language Processing (NLP) is a technology that allows a computer to exploit human languages to perform tasks. Deep learning models have shown excellent results across fundamental tasks in NLP, such as word segmentation, part-of-speech tagging, and named-entity recognition. However, in many situations, these proposed methods fail to perform well. For an NLP system to be robust, it must address issues such as out-of-vocabulary and spelling-mistakes. This thesis's research goal is to develop NLP models that can handle malformed …

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Semi-Supervised Thai Sentence Segmentation Using Local And Distant Word Representations, Chanatip Saetia Jan 2020

Semi-Supervised Thai Sentence Segmentation Using Local And Distant Word Representations, Chanatip Saetia

Chulalongkorn University Theses and Dissertations (Chula ETD)

A sentence is typically treated as the minimal syntactic unit used for extracting valuable information from a longer piece of text. However, in written Thai, there are no explicit sentence markers. We proposed a deep learning model for the task of sentence segmentation that includes three main contributions. First, we integrate n-gram embedding as a local representation to capture word groups near sentence boundaries. Second, to focus on the keywords of dependent clauses, we combine the model with a distant representation obtained from self-attention modules. Finally, due to the scarcity of labeled data, for which annotation is difficult and time-consuming, …

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Deep Sequential Real Estate Recommendation Approach For Solving Item Cold Start Problem, Jirut Polohakul Jan 2020

Deep Sequential Real Estate Recommendation Approach For Solving Item Cold Start Problem, Jirut Polohakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

The item cold-start problem occurs when a recommendation system cannot recommend new items owing to record deficiencies and new listing omissions. When searching for real estate, users can register a concurrent interest in recent and prior projects. Thus, an approach to recommend cold-start and warm-start items simultaneously must be determined. Furthermore, unrequired membership and stop-by behavior cause real estate recommendations to have many cold-start and new users. This characteristic encourages the use of a content-based approach and a session-based recommendation system. Herein, we propose a real estate recommendation approach for solving the item cold-start problem with acceptable warm-start item recommendations …

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A Real Estate Valuation Model Using Boosted Feature Selection, Kankawee Chanasit Jan 2020

A Real Estate Valuation Model Using Boosted Feature Selection, Kankawee Chanasit

Chulalongkorn University Theses and Dissertations (Chula ETD)

To estimate real estate values, a complex valuation model based on artificial neural network (ANN) has been established as a successful means in modern machine learning research, specifically when high-dimensional data are available. Unfortunately, the real estate data in many locations, such as Thailand, are quite limited in terms of features. Hence, it becomes mandatory to reduce the complexity using feature selection techniques. These techniques aim to improve performance by identifying significant factors and help decrease the computational overload and model construction. However, due to the lack of explicability and interpretability in ANNs, the analysis of input factors cannot be …

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Explainable Stock Price Prediction Using Technical Indicators With Short Thai Textual Information, Kittisak Prachyachuwong Jan 2020

Explainable Stock Price Prediction Using Technical Indicators With Short Thai Textual Information, Kittisak Prachyachuwong

Chulalongkorn University Theses and Dissertations (Chula ETD)

A stock trend prediction has been in the spotlight from the past to the present. Fortunately, there is an enormous amount of information available nowadays. There were prior attempts that have tried to forecast the trend using textual information; however, it can be further improved since they relied on fixed word embedding, and it depends on the sentiment of the whole market. In this paper, we propose a deep learning model to predict the Thailand Futures Exchange (TFEX) with the ability to analyze both numerical and textual information. We have used Thai economic news headlines from various online sources. To …

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