Physical Sciences and Mathematics Commons^™

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 …

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 …

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 …

Detection Of Wagyu Beef Sources With Image Classification Using Convolutional Neural Network, Nattakorn Kointarangkul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Wagyu beef originated in Japan. However, there are many types of Wagyu beef in the market around the globe. Primary sources include Australia, USA, Canada and the United Kingdom. The authentic Japanese Wagyu is well known for its intense marbling, juicy rich flavor and tenderness. Observing that there are differences in flavor, texture, and quality between distinct sources of Wagyu. This research presents an AI-based approach to identify Wagyu beef sources with image classification. The input images were collected from reliable sources on the internet and augmented with DCGAN. Deep neural networks, CNN, was constructed to detect the marbled fat …

Learning Personally Identifiable Information Transmission In Android Applications By Using Data From Fast Static Code Analysis, Nattanon Wongwiwatchai

Chulalongkorn University Theses and Dissertations (Chula ETD)

The ease of use of mobile devices has resulted in a significant increase in the everyday use of mobile applications as well as the amount of personal information stored on devices. Users are becoming more aware of applications' access to their personal information, as well as the risk that these applications may unwittingly transmit Personally Identifiable Information (PII) to third-party servers. There is no simple way to determine whether or not an application transmits PII. If this information could be made available to users before installing new applications, they could weigh the pros and cons of having the risk of …

Using Automatic Speech Recognition To Assess Thai Speech Language Fluency In Montreal Cognitive Assessment (Moca), Pimarn Kantithammakorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

The Montreal Cognitive Assessment (MoCA), a widely accepted screening tool for identifying patients with mild cognitive impairment (MCI), includes a language fluency test of verbal functioning where scores are based on the number of unique correct words produced by the test-taker. However, with different languages, it is possible that unique words may be counted differently. This study focuses on Thai as a language that differs from English in its type of word combination. We applied various automatic speech recognition (ASR) techniques to develop an assisted scoring system for the language fluency test of the MoCA with Thai language support. The …

Sop Development For Erp/Software Project Management Of A Consulting Company, Piyanat Viengcome

Chulalongkorn University Theses and Dissertations (Chula ETD)

Presently, ERP/software consulting company has experienced in information gathering process from users in customer company which lead to insufficient to-be process development and vendor selection process. The unexpected results would be extra budget and high manual workload in organization. The possible root cause is uncleared procedure to proceed the project management in ERP/software implementation. The objective of this research is to develop the standard operating procedure for ERP/software project management of a consulting company concentrated in manufacturing industry in Thailand. The methodology starts with studying of competitors' approach from their websites. The ERP expert interview is the next step, 3 …

Accurate Surface Ultraviolet Radiation Forecasting For Clinical Applications With Deep Neural Network, Raksit Raksasat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Exposure to appropriate doses of UV radiation provides enormously health and medical treatment benefits including psoriasis. Typical hospital-based phototherapy cabinets contain a bunch of artificial lamps, either broad-band (main emission spectrum 280-360 nm, maximum 320 nm), or narrow-band UV B irradiation (main emission spectrum 310-315nm, maximum 311nm). For patients who cannot access phototherapy centers, sun-bathing, or heliotherapy, can be a safe and effective treatment alternative. However, as sunlight contains the full range of UV radiation (290-400 nm), careful sun-bathing supervised by photodermatologist based on accurate UV radiation forecast is vital to minimize potential adverse effects. Here, using 10-year UV radiation …

Med-Asa Smart Task-Volunteer Matching System, Taweesin Wongpinkaew

Chulalongkorn University Theses and Dissertations (Chula ETD)

In the context of healthcare, volunteers play an important role in improving the patient's experience and lowering the operational cost. However, the process which facilitate their management is reported to be problematic. In this thesis, the problems of the current system is explored, and a potential solution of a new IT system is outlined. The system was tested for a duration of 2 month during the COVID-19 outbreak in Thailand. SUS and an in-depth interview was conducted in order to gauge the usability and the effectiveness the system. The time it takes for the volunteers to go through with the …

Analysis Of Mass Transfer Coefficient Of Co2 Absorbed By Two-Component Amine Mixture In A Packed Bed Column, Thanakornkan Limlertchareonwanit

Chulalongkorn University Theses and Dissertations (Chula ETD)

Nowadays, coal fired plant has an important role in generating energy all over the world. It affects to greenhouse gases effect (GHGs) and global warming. Carbon dioxide (CO2) is a product of coal combustion that is the amount of number one in the world. However, most of the CO2 usually remove from post-combustion process by chemical absorption which is Monoethanolamine (MEA). Anyway, MEA has a disadvantage such as low CO2 loading and corrosion. Therefore, this study needs to investigate the effect of the mass transfer for a new solvents, 2-(Methylamino)ethanol (2-MAE) and Dimethylaminoethanol (DMAE), compensate for the drawbacks of MEA …

Effect Of Cocatalyst Combination In Titanium-Based Ziegler-Natta Catalyst On Olefin Polymerization, Thanyaporn Pongchan

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research focused on effect of cocatalyst types (TEA, TnOA, and TEA+TnOA) on titanium-based Ziegler-Natta catalyst in olefin polymerization both in slurry and gas-phase systems. This study has been divided into four sections. The commercial titanium-based catalyst was selected to investigate effect of reaction temperature and oxidation state of titanium from ESR measurement on slurry ethylene and propylene polymerization in the first and the second parts, respectively. The commercial catalyst with TEA exhibited the highest activity in ethylene polymerization. However, divalent, and trivalent of titanium (Ti2+ and Ti3+) was active in ethylene polymerization to produce more polymer. Stability of Ti3+ …

Quantum Phases And Phase Transitions In Designer Spin Models, Nisheeta Desai

Theses and Dissertations--Physics and Astronomy

This work focuses on numerical studies of quantum spin systems. These simple models are known to exhibit a variety of phases, some of which have no classical counterpart. Phase transitions between them are driven by quantum fluctuations and the unconventional nature of some such transitions make them a fascinating avenue of study.

Quantum Monte Carlo (QMC) is an indispensable tool in the study of these phases and phase transitions in two and higher dimensions. Nevertheless, we are limited by our inability to simulate models that suffer from the infamous sign problem. While the case of S=1/2 has been studied …

Transverse And Longitudinal Thermal Diffusivity Measurements Of Polymer And Small Molecule Organic Semiconductors With Different Techniques, Maryam Shahi

Theses and Dissertations--Physics and Astronomy

The main thrust of this research was to develop new probes to measure thermal conductivities (κ) of small-molecule crystals, as well as polymer blends of organic semiconductors, both to screen these for possible applications, e.g. as thermoelectric power generators, and to gain an understanding of thermal transport in them. Emphasis has been on the crystals of “TIPS pentacene” [TIPS = 6,13 bis(triisopropylsilylethynyl), and free-standing films of PEDOT:PSS [poly(3,4-ethylenedioxythiophene) polystyrene sulfonate] for different electrochemical and thermoelectric applications. Separate techniques were used for in-plane and transverse thermal conductivities in which 𝜅𝜅 is determined indirectly from measurements of the thermal diffusivity (D ≡ …

Theoretical Studies Of C And Cp Violation In $\Eta \To \Pi^+ \Pi^- \Pi^0$ Decay, Jun Shi

Theses and Dissertations--Physics and Astronomy

A violation of mirror symmetry in the $\eta\to\pi^+\pi^-\pi^0$ Dalitz plot has long been recognized as a signal of C and CP violation. In this thesis, we show how the isospin of the underlying C- and CP-violating structures can be reconstructed from their kinematic representation in the Dalitz plot. Our analysis of the most recent experimental data reveals, for the first time, that the C- and CP-violating amplitude with total isospin I = 2 is much more severely suppressed than that with total isospin I = 0.

In searching for C- and CP-violating sources beyond the SM, we enumerate the leading-dimension, …

Graphene In A Uniform Magnetic Field, Ankur Das

Theses and Dissertations--Physics and Astronomy

We study monolayer graphene in a uniform magnetic field in the absence and presence of interactions. In the non-interacting limit, for p/q flux quanta per unit cell (p, q are coprime integer), the central two bands have 2q Dirac points in the Brillouin zone (BZ) in the nearest-neighbor model. These touchings and their locations are guaranteed by chiral symmetry and the lattice symmetries of the honeycomb structure. If we add a staggered potential and a next-nearest-neighbor hopping we find that their competition leads to a topological phase transition. We also study the stability of the Dirac touchings to one-body perturbations …

The Pion Form Factor And Momentum And Angular Momentum Fractions Of The Proton In Lattice Qcd, Gen Wang

Theses and Dissertations--Physics and Astronomy

Lattice Quantum Chromodynamics (QCD) provides a way to have a precise calculation and a new way of understanding the hadrons from first principles. From this perspective, this dissertation focuses first on a precise calculation of the pion form factor using overlap fermions on six ensembles of 2+1-flavor domain-wall configurations generated by the RBC/UKQCD collaboration with pion masses varying from 137 to 339 MeV. Taking advantage of the fast Fourier transform, low-mode substitution (LMS) and the multi-mass algorithm to access many combinations of source and sink momenta, we have done a simulation with various valence quark masses and with a range …

Large N Fields And Holography, Animik Ghosh

Theses and Dissertations--Physics and Astronomy

We study (nearly) AdS/CFT holography within the context of the Sachdev-Ye- Kitaev (SYK) model. We present a systematic procedure to extract the dynamics of the low energy Schwarzian mode in SYK type models with a single energy scale J and emergent reparametrization symmetry in the infrared within the framework of perturbation theory. We develop a systematic approach using Feynman diagrams in bilocal theory to obtain a formal expression for the enhanced and O(1) corrections to the bilocal propagator and apply this general technique to large q SYK. We show that the Schwarzian theory describes a sector of a general class …

Electrical And Magnetic Transport Properties Of Periodic And Aperiodic Artificial Spin Ice Systems, Justin Woods

Theses and Dissertations--Physics and Astronomy

In recent years, the topic of magnetic frustration in systems and the effect that frustration can have on system dynamics has been a rich environment for study. One such system that lends itself directly to this study are systems of single domain ferromagnetic bars in two dimensions. These ferromagnetic bars can be fabricated from a thin film using current lithography techniques. The bars are fabricated in such a way that their shape anisotropy dictates the magnetization of the bar will be a single domain, Ising-like magnetic moment. These single domain magnetic bars scan be arranged to introduce frustration of their …

Sensitivity Of Electron-Proton Coincidence Asymmetries In Neutron Beta-Decay To Scalar And Tensor Interactions, Subash C. Nepal

Theses and Dissertations--Physics and Astronomy

We study the combined sensitivity of measurements of electron-proton coincidence asymmetries in polarized neutron beta-decay together with a measurement of the electron energy spectrum in unpolarized neutron beta-decay to beyond Standard Model (BSM) scalar and tensor interactions, via the appearance of such BSM physics in the Fierz interference terms b and b_v. Whereas measurements of the electron energy spectrum directly probe b, both the proton and neutrino asymmetries for which experimental results exist are not sensitive to b_v, but effectively to b - b_v. This results in reduced sensitivity to BSM scalar and …

A Theoretical And Experimental Study Of Charge Transport In Organic Thermoelectric Materials And Charge Transfer States In Organic Photovoltaics, Ashkan Abtahi

Theses and Dissertations--Physics and Astronomy

Applications of organic electronics have increased significantly over the past two decades. Organic semiconductors (OSC) can be used in mechanically flexible devices with potentially lower cost of fabrication than their inorganic counterparts, yet in many cases organic semiconductor-based devices suffer from lower performance and stability. Investigating the doping mechanism, charge transport, and charge transfer in such materials will allow us to address the parameters that limit performance and potentially resolve them. In this dissertation, organic materials are used in three different device structures to investigate charge transport and charge transfer. Chemically doped π-conjugated polymers are promising materials to be used …

Effects Of Aperiodicity And Frustration On The Magnetic Properties Of Artificial Quasicrystals, Barry Farmer

Theses and Dissertations--Physics and Astronomy

Quasicrystals have been shown to exhibit physical properties that are dramatically different from their periodic counterparts. A limited number of magnetic quasicrystals have been fabricated and measured, and they do not exhibit long-range magnetic order, which is in direct conflict with simulations that indicate such a state should be accessible. This dissertation adopts a metamaterials approach in which artificial quasicrystals are fabricated and studied with the specific goal of identifying how aperiodicity affects magnetic long-range order. Electron beam lithography techniques were used to pattern magnetic thin films into two types of aperiodic tilings, the Penrose P2, and Ammann-Beenker tilings. SQUID …

Statistical Analysis Of Demographic Effects On Insurance Coverage Of Perinatal And Neonatal Morbidity, Madeline Durbin

Undergraduate Honors Thesis Projects

In the United States of America, Ohio has one of the worst neonatal and perinatal death rates. Within Ohio, Montgomery County has an above average neonatal and perinatal death rate. This statistic can be lowered if more women in Montgomery County have health insurance. They would be more likely to seek out prenatal health care, since they would no longer have to pay as much money out-of-pocket. This would allow medical professionals to be able to diagnose and treat any potential issues in the mother or child earlier. Having health insurance would also prevent mothers-to-be from seeking out other potentially …