Physical Sciences and Mathematics Commons^™

Design And Synthesis Of Purine Based Neuroprotectors And Novel Synthetic Methods For The Trifluoromethylation Of Aldehyde Hydrazones, Puspa Aryal

Doctoral Dissertations

"Purine-derived compounds are widely investigated as cyclin-dependent kinase inhibitors that have broad applications in the design of pharmaceuticals for treating diseases, such as diabetes, atherosclerosis, and cancers. Towards the goal of effective AGE-inhibitors, and neuroprotector compounds we have synthesized a series of novel purine-based triazoles and investigated their neuroprotective effects, using SHSY-3Y human neuroblastoma cell line. Through these studies, we have identified purine-based neuroprotector compounds that favorably modulate oxidative stress induced by the Fenton reaction-generated reactive oxygen species (ROS).

The C(sp²−H)-trifluoromethylation of hydrazones would give access to the αtrifluoromethylated hydrazones that can serve as intermediates in the synthesis …

Depositional Conditions, Stratigraphic Evolution, And Allo- And Autogenic Controls Of Lower Permian Non-Marine Carbonate Rocks, Lucaogou Low-Order Cycle, Bogda Mountains, Nw China, Yiran Lu

Doctoral Dissertations

"The overall objective of this study is to interpret the depositional conditions of lacustrine carbonate deposits of the lower Permian Lucaogou low-order cycle in the greater Turpan-Junggar continental rift basin, NW China. The depositional environments of ten carbonate lithofacies in the Tarlong-Taodonggou half graben and the Zhaobishan section were interpreted. Allo- and autogenic factors were identified. They controlled characteristics and distribution pattern of carbonate deposits in regional and local scale, respectively. Allogenic factors include the amount and direction of regional siliciclastic input, basin geometry, cyclic humidity/aridity oscillation, temperature, and regional tectonics. Autogenic factors include local siliciclastic input, local topography, local …

Disequilibrium Melting Of The Continental Crust During Emplacement Of The Mt. Princeton Batholith, Central Colorado Volcanic Field, Loren A. Bohannon

Graduate Theses/Dissertations

Assimilation and crystallization are difficult to constrain at magmatic boundaries, including the interactions of magma with the surrounding country rock. The assumption of the relationship between a magma and what it is intruding upon is relegated to homogenous bodies or epizonal plutons. Realistically, wall rock influences chemical heterogeneity and isotopic variance at the outcrop scale and changes depending on distance from the magma-wall rock interface. Here, we present a case study of the 35 Ma Mt. Princeton Batholith and the host Precambrian rocks of the Central Colorado Volcanic Field. We assess chemical heterogeneity by whole rock and mineral trace element …

Options Portfolio Optimization And Hedging Of Exotic Options Written On Mini S&P 500 Index In An Illiquid Market With Conditional Value At Risk (Cvar), Benyanee Kosapong

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis investigates the derivatives for portfolio optimization. Risk measures such as Mean Variance (MV), Value-at-Risk (VaR), and Conditional Value-at-Risk (CVaR) are minimized. However, we focus primarily on CVaR because it is a coherent and convex risk measure. We adopt the method of Rockafellar and Uryasev (Journal of Risk 2, 3 (2000)), which minimizes CVaR for shares and convert this method to use with options written on the S&P500 Mini Index. The distribution is known and the index values are simulated by using the VG distribution, over CVaR constraints. In particular, the approach can be used for minimizing the CVaR …

Numerical Solutions For One– And Two–Dimensional Shallow Water Equations Based On Finite Integration Method With Chebyshev Expansion, Lalita Apisornpanich

Chulalongkorn University Theses and Dissertations (Chula ETD)

No abstract provided.

Mass Ratio Variance Majority Cleansing And Minority Oversampling Technique For Class Imbalanced, Piboon Polvimoltham

Chulalongkorn University Theses and Dissertations (Chula ETD)

A sampling method is one of the basic methods to deal with an imbalance problem appearing in machine learning. A dataset having an imbalance problem has a noticeably skewed distribution among different classes. There are three types of sampling techniques to solve this problem by balancing class distributions, undersampling technique, over-sampling technique, and combined sampling technique. In this research, the mass ratio variance scores of each data point of the same class are computed and used to remove noise from a majority class and synthesise instances from a minority class. The results of this proposed sampling technique improve recall over …

Identifying The Most Distinctive Characteristics Of A Good Solution For Non-Euclidean Cvrp Using Statistical Learning Model, Piyabut Inbunsong

Chulalongkorn University Theses and Dissertations (Chula ETD)

A capacitated vehicle routing problem (CVRP) is a well-known NP-hard combinatorial optimization. Therefore, heuristics are the common methods used to search for a good solution. The algorithms will perform better if characteristics of good solutions of the problem are known. There was a research study in the characteristics of Euclidean CVRP solutions and the knowledge was later applied in a metaheuristic. That study becomes our motivation to study the characteristics of non-Euclidean CVRP solutions. To that end, we considered the solutions of non-Euclidean CVRP in the new Euclidean space with the same or higher dimensions using multi-dimensional scaling in which …

Stochastic Control Model With Carrying Capacity Of Population Management Policy For Squirrels In Durian Orchards, Sasiwimol Auepong

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this thesis, the problem that squirrels ruin durian, which is an economic important fruit in Thailand, is considered. We seek for a strategy on squirrel elimination under the consideration that squirrels are not alien species in Thailand and also orchard ecosystem. The problem is solved through a stochastic control model. The population dynamics of squirrels is constructed as a controlled stochastic differential equation with carrying capacity, since we consider the squirrel population in a confined orchard. A performance index indicating the total benefit of a given squirrel elimination strategy is provided. The index comprises the countermeasure cost, resources loss, …

Finite Integration Method Using Chebyshev Expansion For Solving Heat Equation With Non-Local Boundary Conditions, Thanakorn Prasansri

Chulalongkorn University Theses and Dissertations (Chula ETD)

No abstract provided.

Numerical Algorithm For Heat Equation With Moving Boundary Using Finite Integration Method With Chebyshev Polynomial Expansion, Warunya Wong-U-Ra

Chulalongkorn University Theses and Dissertations (Chula ETD)

No abstract provided.

Estimating Stock Price Based On Information From Financial Statement Using Machine Learning Approach, Thitikun Kunathananon

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study introduces a new tool for stock market investors and institutions constructed from Long Short-Term Memory (LSTM) for predicting stock prices. By effectively analyzing financial statements and stock market data, LSTM provides a fast, unbiased, low-cost solution for stock price prediction, intending to increase profits for investors and reduce losses. The study results indicate that LSTM can maintain effectively captures complex relationships in the data and predicts stock prices. This research highlights the potential of LSTM as a valuable and innovative tool for investors and institutions in the stock market.

Real-Time Image Classification For Malignant Biliary Strictures On Cholangioscopy Images Based On Deep Learning Approach, Passakron Phuangthongkham

Chulalongkorn University Theses and Dissertations (Chula ETD)

It is challenging to determine if the cause of bile duct strictures is benign or malignant. Currently, endoscopists may more precisely inspect the bile duct thanks to computerized single-operator cholangioscopy. As a result, lesions in the bile duct can be seen with the naked eye. However, endoscopists continue to diagnose patients differently. Consequently, a biopsy is typically regarded as the gold standard. The necessity to repeat operations results from a biopsy sample mistake that results in a false-negative cancer diagnosis. In this study, we suggest a convolutional neural network developed particularly for real-time malignant biliary stricture classification. Our approach, which …

Corporate Credit Rating Prediction Using Deep Learning, Napasorn Thavichaigarn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Corporate credit rating has an important role in reducing asymmetric information between investors and borrowers and assisting investors as a signal of the entities’ performance and creditworthiness for making appropriate investment decisions in a company’s assets. The economic distress has negatively affected various businesses and resulted in company rating transitions. This led to a problem in adjusting investment strategy and a serious loss as there is a lack of time between officially announced credit rating transitions and real transition. This study provides alternative methods for credit rating prediction by applying machine learning models; Support Vector Machine (SVM), Linear Regression, and …

Multi-Agent Deep Reinforcement Learning For Cryptocurrency Trading, Kittiwin Kumlungmak

Chulalongkorn University Theses and Dissertations (Chula ETD)

Reinforcement learning has emerged as a promising approach for enhancing profitability in cryptocurrency trading. However, the inherent volatility of the market, especially during bearish periods, poses significant challenges in this domain. Existing literature addresses this issue through the adoption of single-agent techniques such as deep Q-network (DQN), advantage actor-critic (A2C), and proximal policy optimization (PPO), or their ensembles. Despite these efforts, the mechanisms employed to mitigate losses during bearish market conditions within the cryptocurrency context lack robustness. Consequently, the performance of reinforcement learning methods for cryptocurrency trading remains constrained within the current literature. To overcome this limitation, we present a …

Real-Time Gastric Intestinal Metaplasia Semantic Segmentation With Multiple Abnormalities Using Deep Learning Approach, Passin Pornvoraphat

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis declares the segmentation of gastric intestinal metaplasia (GIM) in real-time. Recently, GIM segmentation of endoscopic images has been conducted to distinguish GIM from a healthy stomach. However, achieving real-time detection is difficult. Challenging conditions include multiple color modes (white light endoscopy and narrow-band imaging), other abnormal lesions (erosion and ulcer), noisy labels, etc. Herein, our model is based on BiSeNet and can overcome the many issues regarding GIM. Applying auxiliary head and loss boosts the performance on multiple color modes. In addition, pre-processing techniques, including location-wise negative sampling, jigsaw augmentation, and label smoothing, are utilized to improve detection …

Nft-Based Authentic Product Verification And Trading Platform, Natchapol Thongruang

Chulalongkorn University Theses and Dissertations (Chula ETD)

Counterfeit product has been a major problem to the economy for a while. The effect seems to be larger when it comes to the luxury product segment. When the consumers were unsure if the product that they are buying is genuine or not and its cost is very high, then the severity will become even greater. Among the countless number of attempts to fix this solution, utilizing blockchain technology is one of the most popular approaches for present days. In anti-counterfeit domain, associating an NFT token to a physical product is the most common approach. It allows us to unlock …

Combining Technical Analysis And Deep Learning Models For Stock Market Trading, Phurinut Pholsri

Chulalongkorn University Theses and Dissertations (Chula ETD)

The issuance of stocks constitutes a means by which ownership in a company is represented, and its distribution may vary depending on whether the company is limited or public. The stock market offers the potential for high returns, thereby serving as an attractive avenue for investment. Against this backdrop, the objective of this study is to develop a predictive model for stock prices that can facilitate profitable trading outcomes. To achieve this aim, the study focuses on intraday and hourly trading and utilizes a hybrid model that integrates Bidirectional Long Short-Term Memory (BiLSTM) and Convolutional Neural Network (CNN) architectures, along …

Xgboost For Prediction Of Ethereum Short-Term Returns Based On Technical Factor, Wipawee Nayam

Chulalongkorn University Theses and Dissertations (Chula ETD)

Unlike traditional currencies that rely on centralized such as banks or governments, cryptocurrencies today have become popular due to its decentralized transactions. Decentralization takes advantage of no requirement for intermediaries, thus reducing transaction fees and processing time. However, investing in cryptocurrencies incurs risks and uncertainties due to price volatility and rapid changes. The fact that prediction of asset prices is complex due to the influence of multiple factors on price movements. This paper studied the technical factor to analyze the short-term returns of Ethereum in the periods of 1-10 days. The historical data containing Ethereum closing price are collected from …

Y-X-Y Encoding For Identifying Types Of Sentence Similarity, Thanaporn Jinnovart

Chulalongkorn University Theses and Dissertations (Chula ETD)

The task of finding semantic similarity of any two arbitrary sentences consists of two main steps, which are encoding sentences to produce feature vectors of equal length and measuring the similarity, respectively. The quality of an encoding technique can determine the degree of success a model can achieve in measuring the similarity. This is because a good representation is subjected to how finely established the spectrum of similarities is. The clearer the definition of similarity is, the better the representations can be constructed. This, in turn, helps distinguish between types of sentences. Generally, all existing methods for measuring similarity were …

Real-Time Object Detection For Screening Cannabis Seed Gender, Prachya Boonsri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Perception and understanding of cannabis are more expansive than they formerly were. Almost all growers are primarily interested in getting harvests of big flower buds from cannabis female plants since THC, CBD and other cannabinoids are found in female flowers and valuable for medical and industrial market segments. Selecting only female seeds to cultivate is thus an important step to produce THC, CBD profitably. Unfortunately, outdoor cultivation in Thailand traditionally grows regular cannabis seeds that grow up of mixed male and female plants. The male plants will be later spot and eliminated during the pre-flowering stage. This incurs the higher …

Class-Level And Token-Level Approaches For Test Impact Analysis, Alon Basin

Chulalongkorn University Theses and Dissertations (Chula ETD)

The objective of the thesis is to examine the efficacy of test impact analysis in a setting of continuous testing, where automated test cases are routinely run to guarantee the integration of high-quality codes. While continuous testing can enhance code quality and minimize maintenance workload, it also leads to a notable rise in overhead for test execution. In our study on test impact analysis, we developed a novel static class level technique that utilizes JavaParser to create a dependency graph between test cases and source code classes based on abstract syntax trees. We applied this technique to seven Java systems …

Investigation Of Mass Wasting In The Vicinity Of Khao Kho, Central Thailand Using Time – Series Insar Technique, Nuttavit Kumvijairat

Chulalongkorn University Theses and Dissertations (Chula ETD)

The application of time-series InSAR has been employed for investigation of mass wasting in the Khao Kho and Phetchabun mountain range. The objective of this study is to Investigation of mass wasting by SAR data between 2015 to 2018 and classification of mass wasting by displacement rate millimeter/year. This study using active remote sensing data, which is Synthetic Aperture Radar (SAR) satellite imagery from Sentinel-1A and Sentinel-1B satellites. Result from PSInSAR analysis yielded a total of 7,354 PS points for ascending orbit, and 8,984 PS point for descending orbit. The average ground displacement rate result from ascending orbit is 65.19 …

An Analysis On Trends Of Research Topics In Civic Education Using Dynamic Topic Model, Poon Thongsai

Chulalongkorn University Theses and Dissertations (Chula ETD)

The aim of this thesis is to study the trend of civic and citizenship education research from 2000 to 2020 and the influence the regional background of researches has on the research discussion. Relevant data is collected from ERIC and SCOPUS database. This includes abstracts, published year, regional background of researchers, and author h-index. The keywords used are “civic education” or “citizenship education” or “civics”. There are 4917 papers extracted in total. Upon doing further preparation, 4854 articles are prepared for analysis. We apply Structural Topic model (STM) technique to the abstracts with covariates including the published year and the …

Knowledge, Attitude And Practices On Potato Pest Management Of Ethnic Farmers In Southern Shan State, Myanmar, Pyae Pa Pa Aung

Chulalongkorn University Theses and Dissertations (Chula ETD)

Potato is cultivated as the main tuber crop which is essential for ethnic farmers’ household income in Southern Shan State, Myanmar. Most ethnic farmers use chemical pesticides widely to enhance crop yield and to control pests in the farm. The use of chemical pesticides could lead to a series of health impacts of the farmers and environmental issues. The main aim of the study is to explore farmers’ knowledge, attitude and current farm practices on pest management in potato production. The participants of 100 farmers were chosen from each village with a cluster and purposive sampling technique using structured questionnaires …

Geomorphological Change Of The Upper Yom River In Phrae Province, Kakkhanang Na Nan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Yom River is the main tributary of the Chao Phraya River; the upper Yom River flows through Phrae Province. This research selected the upper Yom River because of meander processing in an active basin, which rapidly migrates and changes landforms all the time, The object of this research is to study geomorphological change, thickness and behavior of the upper Yom River in Phrae Province. By assessing aerial photographs and satellite images from 1954 to 2019, the researchers were able to interpret the geological changes that occurred over the past 65 years. The study identified several geomorphological changes from channel migration …

Typology And Formation Of Pothole Along The Mekong River And Erosional Remnant In Sandstone Of Khorat Group, Ubon Ratchathani Province, Northeastern Thailand, Sirawat Udomsak

Chulalongkorn University Theses and Dissertations (Chula ETD)

Phachan Samphanbok Geopark showcases fascinating erosional features, such as a multitude of potholes in the Mekong River. Additionally, it is home to the largest pedestal rock in Thailand, located in Ubon Ratchathani province in the northeastern part of the country, near the border between Thailand and Laos PDR. The formation of potholes is attributed to the erosive force of swirling sediment within fractures caused by vortex currents. In this research study on pothole evolution, the potholes in the Mekong River were categorized into two main groups: structural control potholes and non-structural control potholes. These types were further divided into five …

Analysis Of Fatty Acid Methyl Esters By Two-Dimensional Gas Chromatography Using Cryogen-Free Modulator, Adrian Jose Sacan

Chulalongkorn University Theses and Dissertations (Chula ETD)

A simple and environmentally friendly method in two-dimensional gas chromatography coupled with mass spectrometry (GC-MS) and flame ionization detector has been developed for the analysis of fatty acids in commercial milk products. This applies splitter-based non-cryogenic artificial trapping (SNAT) modulator with unique feature imitating the cryogenic modulation process. The method involves chemical derivatization into fatty acid methyl esters (FAME) with methanolic potassium hydroxide, liquid-liquid phase extraction using hexane, and determination of the FAME composition. The GC×GC approach revealed improved separation of FAME using SNAT modulator with better separated peaks, a ten-fold higher total peak capacity and improved compound identification, compared …

Lead Removal From Water By Modified Activated Carbon Produced From Banana Stem, Imelda Octa Tampubolon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Banana stem-activated carbon (BSAC) and modified banana stem-activated carbon, containing sulfur, nitrogen, and oxygen-containing groups derived from banana stem, were prepared and studied for Pb(II) ion removal. The materials were characterized by scanning electron microscopy, X-Ray diffraction, surface area analysis, and Fourier transform infrared spectroscopy. SEM images showed that the materials are porous, and XRD confirmed that the structures are amorphous and resemble the graphitic hexagonal structure of carbon materials. Surface areas of these materials ranged from 517.67 m2/g for the bare banana stem activated carbon to 234.03, 453.74, 252.97, and 22.96 m2/g for sulfur, oxygen, sulfur and oxygen and …

The Potential Risk And Occupational Exposure Of Pesticides Among Rice Farmers In Delta Ayeyarwady Division, Myanmar, Moe Thu Khin

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aims to assess the potential risk and occupational exposure of pesticides among rice farmers in the Delta Ayeyarwady Region, Myanmar. A cross-sectional study was carried out with 454 rice farmers from March-April 2022. Data collection was done through face-to-face interviews used with a semi-structured questionnaire. The study showed that the mean age of farmers was 44.36 years old while the range was 16 and 74 years old. Rice farmers' average weight (± standard deviation) was 56.86 (± 7.30) kg. In this study, over two-thirds of the rice farmers (77 %) had a moderate level of knowledge regarding environmental …

Assessment Of Greenhouse Gases Emissions From Dairy Cattle Production In Thailand, Phoo Pwint Pwint Thu

Chulalongkorn University Theses and Dissertations (Chula ETD)

Thailand’s agriculture sector plays a vital role in driving economic growth. Globally, livestock production is estimated to contribute about 18% of greenhouse gas (GHG) emissions. Despite its importance, there is a relative lack of research on GHGs assessment in the livestock sector in Thailand. The aim of this research was to estimate GHGs emissions from dairy cattle production in Saraburi and Ratchaburi provinces of Thailand. The 2019 Refinement to the 2006 IPCC guidelines for national greenhouse gas inventories was applied in this research. Twenty dairy farms (n=20) including both small farms (n=10) and medium farms (n=10) were selected as the …