Showing papers by "Mahidol University International College published in 2019"

Sentiment Classification Using Document Embeddings Trained with Cosine Similarity.

Abstract: In document-level sentiment classification, each document must be mapped to a fixed length vector. Document embedding models map each document to a dense, low-dimensional vector in continuous vector space. This paper proposes training document embeddings using cosine similarity instead of dot product. Experiments on the IMDB dataset show that accuracy is improved when using cosine similarity compared to using dot product, while using feature combination with Naive Bayes weighted bag of n-grams achieves a new state of the art accuracy of 97.42%. Code to reproduce all experiments is available at https://github.com/tanthongtan/dv-cosine

Structure guided design of an antibacterial peptide that targets UDP-N-acetylglucosamine acyltransferase

Abstract: UDP-N-acetylglucosamine (UDP-GlcNAc) acyltransferase (LpxA) catalyzes the first step of lipid A biosynthesis, the transfer of an R-3-hydroxyacyl chain from its acyl carrier protein (ACP) to the 3-OH group of UDP-GlcNAc. Essential in the growth of Gram-negative bacteria, LpxA is a logical target for antibiotics design. A pentadecapeptide (Peptide 920) with high affinity towards LpxA was previously identified in a phage display library. Here we created a small library of systematically designed peptides with the length of four to thirteen amino acids using Peptide 920 as a scaffold. The concentrations of these peptides at which 50% of LpxA is inhibited (IC50) range from 50 nM to >100 μM. We determined the crystal structure of E. coli LpxA in a complex with a potent inhibitor. LpxA-inhibitor interaction, solvent model and all contributing factors to inhibitor efficacy were well resolved. The peptide primarily occludes the ACP binding site of LpxA. Interactions between LpxA and the inhibitor are different from those in the structure of Peptide 920. The inhibitory peptide library and the crystal structure of inhibitor-bound LpxA described here may further assist in the rational design of inhibitors with antimicrobial activity that target LpxA and potentially other acyltransferases.

Optimal and general out-of-order sliding-window aggregation

Abstract: Sliding-window aggregation derives a user-defined summary of the most-recent portion of a data stream. For in-order streams, each window change can be handled in O(1) time even when the aggregation operator is not invertible. But streaming data often arrive inherently out-of-order, e.g., due to clock drifts and communication delays. For such streams, prior work resorted to latency-prone buffering or spent O(log n) time for every window change, where n is the instantaneous window size. This paper presents FiBA, a novel real-time sliding window aggregation algorithm that optimally handles streams of varying degrees of out-of-orderness. FiBA is as general as the state-of-the-art and supports variable-sized windows. An insert or evict takes amortized O(log d) time, where d is the distance of the change to the window's boundary. This means O(1) time for in-order arrivals and nearly O(1) time for slightly out-of-order arrivals, tending to O(log n) time for the most severely out-of-order arrivals. We also prove a matching lower bound, showing optimality. At its heart, the algorithm combines and extends finger searching, lazy rebalancing, and position-aware partial aggregates. Further, FiBA can answer range queries that aggregate subwindows for window sharing. Finally, our experiments show that FiBA performs well in practice and conforms to the theoretical findings, with significantly higher throughput than O(log n) algorithms.

Relevant Factors for Success as an Online Entrepreneur in Thailand

Abstract: This research aims to study the success factors of an online entrepreneur. With the recent rapid growth of the online market for different goods and services, the need to investigate the business s...

Effects of unconventional recreational drug use in pregnancy.

Abstract: Recreational drug toxicity is a rapidly evolving aspect in clinical practice. The prevalence of recreational drug abuse in the past decade has achieved an epidemic scale due to invention of new agents and ease of accessibility to the abused drugs. "Unconventional recreational drugs" is the term that includes new psychoactive drugs and medications diverted for recreational goals. Misuse of unconventional recreational drugs during pregnancy can affect both the pregnant woman and the fetus. However, the problems are usually unrecognized and overlooked by healthcare professionals. In this articles, obstetric complications, teratogenicity and neonatal abstinence syndrome from exposure during pregnancy to synthetic cannabinoids, synthetic cathinones, tramadol, kratom, olanzapine, quetiapine, ketamine and ketamine are reviewed. The main purpose is to create awareness about maternal, fetal and neonatal effects of these unconventional recreational drugs, so healthcare professionals will have improved vigilance for these under-recognized issues.

How to lead the millennials: a review of 5 major leadership theory groups

Abstract: Millennials are currently taking over the global workforce. While practitioners and scholars have recognized their different work values from previous generations, research on this topic is still scarce. Furthermore, the current leadership theories have tended to focus mainly on the characteristics of leaders without adequately examining the leadership styles that work best for the millennials. Using a literature review from the top tier leadership journals, this paper aims to provide a more comprehensive framework to provide new directions for the development of leadership theory by understanding the millennials’ perspective on leadership. This study thus contributes to the current literatures by using five thematic leadership groups to develop the most optimum leadership style for leading the Millennials. The advantages and disadvantages of using neo-charismatics, leadership and information processing, social exchange/relational leadership, ethical/moral leadership, and e-leadership theories in leading millennials are assessed. Results show that no single leadership theory is adequate for leading the millennials optimally. Hence, mixing the dimensions of different leadership theory groups is suggested. As for the leadership theory aspects, it is recommended to scholars to consider developing more flexible leadership theory models that can accommodate different generational groups.

Sustainability as a place brand position: a resident-centric analysis of the ten towns in the vicinity of Bangkok

Abstract: A number of cities and towns have used sustainability as a brand position, but most appear to have focused on the environmental aspect of sustainability, while the adoption of other dimensions of sustainability, including social and economic, has been limited. The objective of this study is to create a branding tool that can help towns develop a brand position that is credible, drives growth, involves residents and fosters sustainability. This sustainable place branding analysis was adapted from the importance–performance analysis widely used in business and in the tourism industry. The data were collected from the residents of ten towns in the vicinity of Bangkok, Thailand. The tool provides mayors with a holistic analysis of sustainability, suggests dimensions to be considered in the brand position and guides strategic actions to sustainably develop places. From the findings, the authors suggest five types of sustainable towns that the mayors of the ten towns can adopt as a brand position: elegant, compassionate, lively, peaceful and green.

Proteochemometric Modeling for Drug Repositioning

Abstract: The rising cost of drug development has necessitated the search for efficient approaches for the discovery of novel drugs. Such difficulty arises from the fact that promising lead compounds would need to be further scrutinized via preclinical and clinical studies so as to characterize their absorption, distribution, metabolism, excretion, and toxicity in order to verify their safety for clinical use. In this respect, drug repositioning/repurposing represents an attractive venue for the discovery of novel therapeutic indications for existing food and drug administration-approved drugs, which in a nutshell repurposes old drugs for treating new diseases for which they were not originally developed. Computational approaches have been instrumental in drug repositioning efforts as they make use of existing biological and chemical data to uncover new therapeutic indications by relying on the concept that similar compounds bind to similar targets. Quantitative structure-activity relationship (QSAR) is a powerful ligand-based approach that correlates structural features of compounds with their observed biological activity against a single target protein. Proteochemometric modeling (PCM) extends QSAR to an extra dimension by allowing several target proteins to be considered in a single model. This chapter briefly explores the concepts of polypharmacology and computational drug discovery and finally examines the use of PCM for drug repositioning.

Clock Reaction Revisited: Catalyzed Redox Substrate-Depletive Reactions.

Abstract: Quantitative demonstration of chemical kinetics often requires sophisticated equipment and materials. By using inexpensive and commonly available chemicals, we propose here two clock reactions, oxygen–safranin–benzoin clock and cysteine–iodine–hydrogen peroxide clock. Students simply measure and add stock solutions to start clock reactions. Sudden discoloration or coloration of the reaction mixture marks the end of the reaction, and this can be conveniently timed. Students then complete calculations and graphing in a spreadsheet file by following common protocols. Rates of reaction are calculated from the ratio of [limiting reactant]0 and clock time. Orders of reactions and rate constants are determined by the method of initial rate. Additional discussions on topics such as catalysis, reaction mechanism, redox reaction, and pseudo-zeroth-order reaction are also possible.

Food Tourism, Policy and Sustainability: Behind the Popularity of Thai Food

Abstract: Behind the success of Thailand’s food tourism lies national strategies and initiatives promoting the globalisation of Thai food. This chapter analyses government policies related to the food and tourism industries and investigates the evolution of food production and food tourism development in terms of food supply and sustainable food tourism. The economic sustainability of food production and distribution has been the focus of the past 17 years of Thai food policies. Meanwhile, the approach to gastrodiplomacy has successfully created positive images and global awareness of Thainess and increased inbound food tourism to the country. While the sustainability of the food supply chain has not yet been incorporated into food tourism, the potential for gastrodiplomacy to be implemented in the tourism sector is discussed in terms of tourists’ engagement with the different stages of the food supply chain, and how sustainability will in time be achieved through food tourism.

Parallel Streaming Random Sampling

Abstract: This paper investigates parallel random sampling from a potentially-unending data stream whose elements are revealed in a series of element sequences (minibatches). While sampling from a stream was extensively studied sequentially, not much has been explored in the parallel context, with prior parallel random-sampling algorithms focusing on the static batch model. We present parallel algorithms for minibatch-stream sampling in two settings: (1) sliding window, which draws samples from a prespecified number of most-recently observed elements, and (2) infinite window, which draws samples from all the elements received. Our algorithms are computationally and memory efficient: their work matches the fastest sequential counterpart, their parallel depth is small (polylogarithmic), and their memory usage matches the best known.

Teaching Boyle’s Law and Charles’ Law through Experiments that Use Novel, Inexpensive Equipment Yielding Accurate Results

Abstract: We discuss the use of a simple piece of equipment made of a 50 mL syringe attached to a 2 mL graduated pipet to demonstrate Boyle’s law and Charles’s law. A plot of the hydrostatic pressure against...

Feature Comparison for Automatic Bug Report Classification

Abstract: Nowadays, various bug tracking systems (BTS) such as Jira, Trace, and Bugzilla have been developed and proposed to gather the issues from users worldwide. This is because those issues, called bug reports, contain a significant information for software quality maintenance and improvement. However, many bug reports with poor quality might have been submitted to the BTS. In general, the reported bugs in the BTS are firstly analyzed and filtered out by bug triagers. However, with the increasing amount of bug reports in the BTS, manually classifying bug reports is a time-consuming task. To address this problem, automatically distinguishing of bugs and non-bugs is necessary. To the best of our knowledge, this task is never easy for bug reports classification because the problem of bug reports misclassification still occurs to date. The background of this problem may be arise from using inappropriate or confusing features. Therefore, this work aims to study and discover the most proper features for binary bug report classification. This study compares seven features such as unigram, bigram, camel case, unigram+bigram, unigram+camel case, bigram+ camel case, and all features together. The experimental results show that the unigram+camel case should be the most proper features for binary bug report classification, especially when using with the logistic regression algorithm. Consequently, the unigram+camel case should be the proper feature to distinguish bug reports from the non-bugs ones.

Board characteristics, state ownership and firm performance: evidence from Vietnam

Abstract: This paper investigates the association between board characteristics and firm performance and examine whether such relationship is moderated by different levels of ownership concentration among Vietnamese listed firms from 2008 to 2014. A series of fixed effect panel regressions was employed to test the impact of ownership concentration on corporate governance-firm performance relationship. The results indicate that the impact of an effectiveness of corporate governance mechanism on firm performance is influenced by the different levels state ownership. The evidence of this study suggests that corporate governance system that is beneficial for other developed markets may not be a good fit for emerging markets. Corporate governance policies in Vietnam are in the process of being reformed, and the results, thus, will provide insights for regulatory bodies by helping them better understand corporate governance practices.

Halogen bonds in N-bromosuccinimide and other N-halosuccinimides

Abstract: Our crystal data shows marked intermolecular Br interaction with a neighboring O (carbonyl) in the crystal, Br---O(carbonyl) = 2.767(1) A, well below the sum of the corresponding van der Waals radii, 3.37 A. This C=O---Br interaction is among the shortest in the CSD (only 8/2185 examples have a similar distance 2.725–2.800 A). Only one carbonyl group interacts with the halogen atom, thus inducing a helical intermolecular arrangement. The halogen bond was also studied with density functional theory (DFT) methods, based on coordinates of two molecules in the crystal packing, widely modifying the N-Br---O(carbonyl) angle. In each calculation, this angle was fixed, and the corresponding arrangements were analyzed for potential structural correlation. Indeed, the widening of the N-Br---O(carbonyl) angle correlates with a gradual increase of halogen bond interaction Br---O(carbonyl), that is, shorter separation. It is also seen that decreasing the N-Br---O(carbonyl) angle is associated with decreasing Br---Br separation. Isosurface electron density shows the presence of Br sigma-holes in the two-molecule arrangements.

Utilizing Google Translated Reviews from Google Maps in Sentiment Analysis for Phuket Tourist Attractions

Abstract: Well-known tourist attractions receive reviews in various languages. Google Maps has a reviewing system with translation service. The translated reviews may not perfectly represent the original review, but may still capture valuable information. This paper studies the effectiveness of nonusing translated reviews in sentiment analysis for tourist attractions in Phuket, Thailand. Reviews for beaches in Phuket and nearby islands are collected. The reviews are separated into two groups, reviews originally written in English and non-English. Rather than discarding non-English reviews or constructing models for each origin language, we experiment with different ways of utilizing the non-English reviews by translating them into English. Results show that models constructed using the reviews originally written in English are also effective for translated reviews. This can significantly reduce the effort to understand the sentiment of reviews written in various languages by training only one model and applying it to text translated from any language.

Chemical Patterns in Autoxidations Catalyzed by Redox Dyes.

Abstract: We present simple and effective experiments to produce intricate chemical patterns from common chemicals in a classroom setting. Students selected an independent variable of their interest, designe...

Wetzel's sector covers unit arcs

Abstract: We settle J. Wetzel's 1970's conjecture and show that a 30{^\circ} circular sector of unit radius can accommodate every planar arc of unit length. Leo Moser asked in 1966 for the smallest (convex) region in the plane that can accommodate each arc of unit length. With area {\pi}/12, this sector is the smallest such set presently known. Moser's question has prompted a multitude of papers on related problems over the past 50 years, most remaining unanswered.

Exploring the causal effect of religious piety on dividend policy: evidence from historical religious identification

Abstract: Theory suggests that religious piety is associated with greater risk aversion and more conservative financial policies. Returns to shareholders through dividends are much more certain than returns ...

Thai-Sikh diaspora and identity: participation of Sikh students in the extracurricular activities at the university

Abstract: This article draws from an ethnographic case study of a group of Thai-Sikh diaspora students in an International college of a Thai Public university. It examines the issues related to the identity ...

Do bank-affiliated funds perform better than the others: the higher moment approach

Abstract: In this study, we examine the difference in mutual fund performance between the bank-related and the non-bank-related mutual funds in emerging markets. We further improve the empirical test...

In silico investigation of mitragynine and 7-hydroxymitragynine metabolism.

Abstract: Mitragynine is the main active compound of Mitragyna speciose (Kratom in Thai). The understanding of mitragynine derivative metabolism in human body is required to develop effective detection techniques in case of drug abuse or establish an appropriate dosage in case of medicinal uses. This in silico study is based upon in vivo results in rat and human by Philipp et al. (J Mass Spectrom 44:1249–1261, 2009). Gas-phase structures of mitragynine, 7-hydroxymitragynine and their metabolites were obtained by quantum chemical method at B3LYP/6-311++G(d,p) level. Results in terms of standard Gibbs energies of reaction for all metabolic pathways are reported with solvation energy from SMD model. We found that 7-hydroxy substitution leads to changes in reactivity in comparison to mitragynine: position 17 is more reactive towards demethylation and conjugation with glucuronic acid and position 9 is less reactive towards conjugation with glucuronic acid. Despite the changes, position 9 is the most reactive for demethylation and position 17 is the most reactive for conjugation with glucuronic acid for both mitragynine and 7-hydroxymitragynine. Our results suggest that 7-hydroxy substitution could lead to different metabolic pathways and raise an important question for further experimental studies of this more potent derivative.