Learning to Make Predictions on Graphs with Autoencoders

We examine two fundamental tasks associated with graph representation learning: link prediction and semi-supervised node classification. We present a novel autoencoder architecture capable of learning a joint representation of both local graph structure and available node features for the multi-task learning of link prediction and node classification. Our autoencoder architecture is efficiently trained end-to-end in a single learning stage to simultaneously perform link prediction and node classification, whereas previous related methods require multiple training steps that are difficult to optimize. We provide a comprehensive empirical evaluation of our models on nine benchmark graph-structured datasets and demonstrate significant improvement over related methods for graph representation learning. Reference code and data are available at https://github.com/vuptran/graph-representation-learningComment: Published as a conference paper at IEEE DSAA 201

The potential benefit of oral simethicone in improving colonic visualization and polyp detection in routine colonoscopy screenings

Introduction: Colon cancer is the second leading cause of cancer deaths in the United States among men and women. Many of these cancers can be prevented through regular colonoscopy screening. However, the bowel preps used prior to the screening procedure create a frothy or “bubbly” appearance within the colon. Physicians have tried to overcome this with the flushing of water or using simethicone in the water canister during the procedure, but they have provided minimal efficacy and simethicone damages the colonoscope. As a result, physicians have a difficult time viewing the colonic mucosa and thoroughly inspecting the colon for polyps. Objectives: This study aims to objectively determine if the use of simethicone (Gas X) taken orally after taking the bowel prep has 2 advantages, improving quality of preparation and subsequent increase in polyp detection. Methods: This will be a randomized, single-blinded study comparing a split-dose bowel prep with and without the use of oral simethicone in patients undergoing routine colonoscopy screenings. Both groups will be provided with a standard bowel prep kit. Patients will be randomly assigned prior to receiving their bowel prep kits. Only the patients within the experimental group will additionally receive a single dose of simethicone with their bowel prep. Each patient will receive clear prep instructions, as attached to this proposal. The patients will be informed to drink clear liquids one day prior to the procedure, with no consumption of solid foods and dairy. On the day before their procedure they will be informed to drink their first 5.4-oz bottle at 6 pm the day before their procedure with 40 oz of clear liquids and their second 5.4 oz bottle 5 hours before the morning of their colonoscopy with 24 oz of clear liquids. Patients in the experimental group will be provided with additional instructions informing them to take their given dose of simethicone (Gas-X) approximately 30 minutes after the completion of their second bottle in the preparation. Results: The control group (n=7) showed that 57% of the subjects presented with froth whereas the remainder presented with little froth. One patient was removed due to very poor prep that allowed for minimal visualization of the colon. The experimental group (n=5) showed 100% with no froth during colonoscopy. Post-procedure results showed that 42% of the control group complained of bloating, nausea, and mild discomfort. No participant in the experimental group complained of post-procedure symptoms expressed by the control group. Conclusion: Preliminary results show that more participants are needed to accurately compare the control and experimental group. Based on current results, simethicone does seem to provide some assistance in colonic visualization and overall improvement in patient symptoms following colonoscopy. Additionally, the use of simethicone has shown improved symptoms in the setting of bowel prep for colonoscopy. However, this is not yet statistically significant and requires longer continuation of study

Factors affecting service quality at Vietnamese retail banks

Sustainable growth and development can be the most important lesson that banks have learned in recent decades. Banks would gain many benefits, win the competition and develop sustainably if there have been more and more loyal customers. Customer satisfaction will help build customer loyalty. In order to have loyal customers, service quality must be good. Quality customer service of the bank is to ensure customer satisfaction and take their needs into consideration to improve service quality. High customer service quality will generate value not only to meet customer needs but also the expectations of customers and make banks more prominent than their competitors. This study identifies factors that affect customer satisfaction with the service quality at Vietnamese retail banks. The results are obtained by qualitative and quantitative method. The research model with a questionnaire consisting of 22 variables, 5 scales for a survey of 554 customers, is identified and developed through interviews with experts and group discussions. The findings show that customer satisfaction with the service quality at retail banks is influenced by “reliability”, “responsiveness”, “empathy”, “security”, and “tangibles”. Based on the findings, solutions for improving service quality are proposed for Vietnamese retail banks

Three essays in the corporate use of financial derivatives

This thesis discusses three topics concerned with the corporate use of financial derivatives. The first paper studies the effects of interest rate swaps on firms’ default risk. The second paper examines the relationship between creditor rights and airlines’ hedging behaviour. The final paper investigates how managerial holdings of inside debt (pension benefits and deferred compensation) can impact the decision to hedge via the use of interest rate swaps. The first paper attempts to examine the question of whether the use of interest rate swaps by corporates and the direction of interest rate swaps increase or decrease firms’ probability of default. Our sample consists of United Kingdom (UK) listed non-financial firms for the period between 2001 and 2015. Using a pooled Ordinary Least Squares (OLS) model, we document that the use of interest rate swaps reduces the probability of default for both firms swapping into fixed and those swapping into floating. This result is robust when we use a range of econometric methods, including a fixed effects model, a propensity score matching technique, an instrumental variables approach, and a System Generalised Method of Moments model. Additionally, we find that a failure to account for differences between small and large firms can lead to incomplete or misleading inferences of the impact of interest rate swap usage on firms’ default risk. Our results show that whereas the use of interest rate swaps by small firms, irrespective of the direction of the swap, leads to a reduction in their default risk, large firms that swap into floating-rate debt are associated with an increase in their probability of default. Additionally, we show that the negative impact of swapping into fixed rate debt on firms’ default risk remains the same during the period of heightened economic policy uncertainty, whereas the effectiveness of swapping into floating rate debt in decreasing firms’ probability of default is weakened during this period. Moreover, this paper demonstrates that the recent period of zero lower bound interest rates affects the efficacy of swapping into fixed rate debt versus swapping into floating rate debt. Our results indicate that while swapping into fixed rate debt leads to a reduction in the probability of default during the zero lower bound period, the risk-mitigating effects of swapping into floating rate debt are significantly dampened during this period. In the second paper, we use a sample consisting of airlines from 36 countries over the period from 2002 to 2016 to investigate the impact of creditor rights on corporate hedging behaviour, measured by the extent of jet fuel hedging. Using a pooled Ordinary Least Squares model, we find that airlines undertake more jet fuel hedging in stronger creditor rights countries. These results are robust when we employ other econometric methods, such as a Tobit model, a Heckman model, or an instrumental variable technique. Moreover, we identify six creditor rights reforms during our sample period and employ a model that is akin to a difference-in-difference model. The results show that the change that increases the creditor rights index can lead to an increase in airlines’ jet fuel hedging. In addition, we find that the positive impact of creditor rights on the extent of jet fuel hedging is weakened during the financial crisis but strengthened during periods of high jet fuel prices. This study also sheds new light on the role of hedging in ameliorating the adverse effects of strong creditor rights. We show that jet fuel hedging can boost an airline’s leverage. Furthermore, hedging allows an airline to engage in high-risk but potentially value-enhancing investment activities, therefore alleviating the underinvestment problem observed in strong creditor rights countries. The third paper looks at how managerial compensation incentives, measured using data on the chief executive officer (CEO) pension benefits and deferred compensation (commonly referred to as inside debt), affect the decision to hedge via the use of interest rate swaps. Our sample consists of 912 listed United States (US) firms during the periods from 2006 to 2014. Using a probit model, we show that firms with more CEO inside debt are less likely to use interest rate swaps. Moreover, using a pooled OLS model, we find a negative relationship between CEO inside debt holdings and the extent to which a firm hedges using interest rate swaps. In this paper, we attempt to distinguish between protected and non-protected CEO inside debt. Whereas protected CEO inside debt is funded and secured, the non-protected one is not. Our result suggests that the negative association between CEO inside debt and hedging by interest rate swaps only exists if the CEO inside debt is non-protected. These results are robust when we employ a range of different econometric methods, including a Tobit regression model and an instrumental variables technique. Furthermore, we show that the negative impact of non-protected CEO inside debt is weakened when firms are financially constrained or during periods of heightened interest rate uncertainty. Finally, we document that non-protected CEO inside debt can have negative effects on firms’ default risk. However, our further analysis indicates that the negative effects of non-protected CEO inside debt on firms’ default risk are dampened when firms hedge using interest rate swaps, which can explain why firms with large CEO inside debt holdings hedge less with interest rate swaps

ASSESSING METAL POLLUTION IN GROUNDWATER AT PLEISTOCENE AQUIFER IN GO VAP DISTRICT, HO CHI MINH CITY

The appearance of some metals such as Fe, Al, As and other compounds with artificial origin as Zn, Cu, Pb in groundwater has become issues and being interested to many researchers. In the area of water supply, the problem of metal pollution from some water supply companies and households not only appears in surface water but also in groundwater, which reflected in the metal contamination over permissible standards and seasonal oscillations. In this study, a survey of current pollution was carried out to elucidate the distribution of some metal ions such as total iron, Al3+, As5+, Cu2+, Pb2+ and Zn2+ in groundwater in Go Vap District. The results showed that these metals are distributed mainly at mid-upper Pleistocene aquifer (qp2-3) from 8 meters to over 40 meters and in strongly to moderately acidic environment, which have pH from 4.2 to 5.0. As results, this study shows that these metals in groundwater related to the origin and sediments composition of permeable and impermeable aquifers. In addition, the metal pollution such as Cu2+, Pb2+ and Zn2+ in recent years may be due to the artificial origin