Digital Commons Network^™

Generating Face Images With Attributes For Free, Yaoyao Liu, Qianru Sun, He Xiangnan, Liu An-An, Su Yuting, Chua Tat-Seng

Research Collection School Of Computing and Information Systems

With superhuman-level performance of face recognition, we are more concerned about the recognition of fine-grained attributes, such as emotion, age, and gender. However, given that the label space is extremely large and follows a long-tail distribution, it is quite expensive to collect sufficient samples for fine-grained attributes. This results in imbalanced training samples and inferior attribute recognition models. To this end, we propose the use of arbitrary attribute combinations, without human effort, to synthesize face images. In particular, to bridge the semantic gap between high-level attribute label space and low-level face image, we propose a novel neural-network-based approach that maps …

Proving Non-Termination By Program Reversal, Krishnendu Chatterjee, Ehsan Kafshdar Goharshady, Petr Novotný, Dorde Zikelic

Research Collection School Of Computing and Information Systems

We present a new approach to proving non-termination of non-deterministic integer programs. Our technique is rather simple but efficient. It relies on a purely syntactic reversal of the program's transition system followed by a constraint-based invariant synthesis with constraints coming from both the original and the reversed transition system. The latter task is performed by a simple call to an off-the-shelf SMT-solver, which allows us to leverage the latest advances in SMT-solving. Moreover, our method offers a combination of features not present (as a whole) in previous approaches: it handles programs with non-determinism, provides relative completeness guarantees and supports programs …

Non-Equivocation In Blockchain: Double-Authentication-Preventing Signatures Gone Contractual, Yannan Li, Willy Susilo, Guomin Yang, Yong Yu, Tran Viet Xuan Phuong, Dongxi Liu

Research Collection School Of Computing and Information Systems

Equivocation is one of the most fundamental problems that need to be solved when designing distributed protocols. Traditional methods to defeat equivocation rely on trusted hardware or particular assumptions, which may hinder their adoption in practice. The advent of blockchain and decentralized cryptocurrencies provides an auspicious breakthrough paradigm to resolve the problem above. In this paper, we propose a blockchain-based solution to address contractual equivocation, which supports user-defined fine-grained policybased equivocation. Specifically, users will be de-incentive if the statements they made breach the predefined access rules. The core of our solution is a newly introduced primitive named Policy-Authentication-Preventing Signature (PoAPS), …

Engaging Drivers Via Competition: A Case Study With Arena, Hao Cheng, Shuyu Wei, Lingyu Zhang, Zimu Zhou, Yongxin. Tong

Research Collection School Of Computing and Information Systems

Sustained work enthusiasms of drivers are crucial for the success of large-scale ride-hailing platforms. In this paper, we conduct the first-of-its-kind exploration to encourage active participation of drivers via competition. We design Arena, a competition where drivers compete for prizes via completing more trips. Through a pilot study covering over 2,600 participants, we uncover the easy-win problem, an overlooked and serious issue in competition design for real-world drivers. It refers to situations where one competitor does not show up during competition whereas the other easily wins. To solve the easy-win problem without impairing motivation of drivers, we devise a novel …

Ganmut: Learning Interpretable Conditional Space For A Gamut Of Emotions, S. D'Apolito, D.P. Paundel, Zhiwu Huang, A.R. Vergara, Gool L. Van

Research Collection School Of Computing and Information Systems

Humans can communicate emotions through a plethora of facial expressions, each with its own intensity, nuances and ambiguities. The generation of such variety by means of conditional GANs is limited to the expressions encoded in the used label system. These limitations are caused either due to burdensome labeling demand or the confounded label space. On the other hand, learning from inexpensive and intuitive basic categorical emotion labels leads to limited emotion variability. In this paper, we propose a novel GAN-based framework which learns an expressive and interpretable conditional space (usable as a label space) of emotions, instead of conditioning on …

On Financial Quotient: Theory And Empirical Analysis, Gang Sun

Dissertations and Theses Collection (Open Access)

Financial Quotient (FQ) has become a common topic of concern in the global academic, business and social communities, but at this stage, academic research on FQ and its education are still immature, theoretical depth and empirical support basis are shortage, and influence factors of FQ and the degree of influence of each factor have not been systematically studied. Therefore, there is a large gap between research and practice.

The purpose of this Paper is to construct a set of scientific and reasonable FQ index for individuals, to find factors that can influence or predict personal financial quotient (PFQ), and to …

Fuelling Effects Of Unique Opinion Holder’S Emotions On Team Creativity: A Collective Information Processing Perspective, Hui Si Oh

Dissertations and Theses Collection (Open Access)

Building on past studies that have found positive influence of minority member on team creativity, this research examined an underexplored yet crucial topic of a unique opinion holder’s happy and anger emotions on team creativity. Using a collective information processing perspective, this study examined whether the expression of anger and happiness would be beneficial for team creativity by spurring team members to respond qualitatively differently to each other’s ideas during the discussion. Additionally, this study examined whether the influence of a unique opinion holder’s emotions on team creativity through information-processing pathways would depend on individual members’ working memory capacities. Three …

Comparing Family Property Disputes In English And Singapore Law: "Context" Is Everything, Man Yip

Research Collection Yong Pung How School Of Law

This paper examines why Singapore law has not followed English law in the area of beneficial ownership of family property. It points out that the landmark cases in the two jurisdictions are underpinned by different family paradigms.The English landmark cases are based on the unmarried cohabitants paradigm and the legal rules that have emerged from these cases are aimed at, whether successfully or not, ensuring a fair division of the family home upon the breakdown of these relationships. In contrast, the Singapore seminal judgments are underlaid by contests between children over their parents’ property which raised questions as to the …

To Switch Or Not To Switch: Individual Differences In Executive Function And Emotion Regulation Flexibility, Wei Xing Toh

Dissertations and Theses Collection (Open Access)

Emotion regulation (ER) constitutes strategies that modulate the experience and expression of emotions. While past work has predominantly focused on each ER strategy independently, recent research has begun to examine individual-difference factors that are associated with the flexible implementation of ER strategies in line with environmental demands (i.e., ER flexibility). Considering that ER processes generally implicate executive function (EF)—a collection of adaptive, general-purpose control processes—it is plausible that EF could be involved in ER flexibility. Using a latent-variable approach based on a comprehensive battery of EF tasks, the present study investigated how the various aspects of EF (i.e., common EF, …

Three Essays On Panel And Factor Models, Ji Feng

Dissertations and Theses Collection (Open Access)

The dissertation includes three chapters on panel and factor models.

In the first chapter, we introduce a two-way linear random coefficient panel data models with fixed effects and the cross-sectional dependence. We follow the idea of the within-group fixed effects estimator to estimate parameters of interests. We establish the limiting distributions of the estimates and also propose the two-way heterogeneity bias test to check the desirability of the estimation strategy. The specification tests then are constructed to examine the existence of the slope heterogeneity and time-varyingness. We study the asymptotic properties of the specification tests and employ two bootstrap schemes …

Culture And Cyber Security: How Cultural Tightness-Looseness Moderates The Effects Of Threat And Coping Appraisals On Mobile Cyber Hygiene, Kok Wei Hoe

Dissertations and Theses Collection (Open Access)

With increasing adoption of smartphone for mobile-commerce and increasing incidents of cyber breaches, it is timely to investigate how the weakest link in this security chain, human, can be strengthened. To date, there has been a gap in research examining the impact of culture on protection motivation. Most extant research focus on technological, organizational and behavioral factors affecting protection motivation. In this study, I develop a model integrating Theory of Cultural Tightness-Looseness and Protective Motivation Theory to investigate how cultural norms, define as shared expectations and rules that guide behavior of people within social groups, affect a person’s intentions to …

Essays On Predictive And Prescriptive Analytics For Risk Monitoring And Population Screening In Healthcare Management, Yan He

Dissertations and Theses Collection (Open Access)

Due to increased aging populations and changes in lifestyles, we have witnessed an increased prevalence of various chronic and acute diseases and a drastic rise in healthcare expenditures in recent years. It is of paramount importance for public health to promote regular screening and close monitoring to detect the early onset of diseases. On the other hand, the increasing availability of healthcare data and advancement in data analytics offer a huge potential to facilitate this goal. We can analyze the vast amount of data and recommend more personalized diagnostic tests after receiving results and signals from screening tests and monitoring …

Happy Lottery Winners And Lottery-Ticket Bias, Seonghoon Kim, Andrew J. Oswald

Research Collection School Of Economics

The world spends a remarkable $250 billion a year on lottery tickets. Yet, perplexingly, it has proved difficult for social scientists to show that lottery windfalls actually make people happier. This is the famous and still unresolved paradox due initially to Brickman and colleagues. Here we describe an underlying weakness that has affected the research area, and explain the concept of lottery‐ticket bias (LT bias), which stems from unobservable lottery spending. We then collect new data—in the world’s most intense lottery‐playing nation, Singapore—on the amount that people spend on lottery tickets (n = 5626). We demonstrate that, once we correct …

Fixtures, Mortgages And Retention Of Title Clauses, Alvin W-L See

Research Collection Yong Pung How School Of Law

This article examines the impact of the doctrine of fixtures on the supply of goods on retention of title terms, particularly where the goods have been affixed to a land that is encumbered by a pre-existing mortgage. As the law now stands, the mortgagee invariably prevails in a priority contest, leaving the supplier with no effective way of protecting its interest. It is argued that the currently broad definition of a fixture requires rethinking to achieve a more balanced treatment of the two parties.

Technological Opportunities For Sensing Of The Health Effects Of Weather And Climate Change: A State-Of-The-Art-Review, V. Anderson, A. C. W. Leung, H. Mehdipoor, B. Janicke, D. Milosevic, A. Oliveira, S. Manavvi, P. Kabano, Yuliya Dzyuban, Et Al

Research Collection College of Integrative Studies

Sensing and measuring meteorological and physiological parameters of humans, animals, and plants are necessary to understand the complex interactions that occur between atmospheric processes and the health of the living organisms. Advanced sensing technologies have provided both meteorological and biological data across increasingly vast spatial, spectral, temporal, and thematic scales. Information and communication technologies have reduced barriers to data dissemination, enabling the circulation of information across different jurisdictions and disciplines. Due to the advancement and rapid dissemination of these technologies, a review of the opportunities for sensing the health effects of weather and climate change is necessary. This paper provides …

Discovering Interpretable Latent Space Directions Of Gans Beyond Binary Attributes, Huiting Yang, Liangyu Chai, Qiang Wen, Shuang Zhao, Zixun Sun, Shengfeng He

Research Collection School Of Computing and Information Systems

Generative adversarial networks (GANs) learn to map noise latent vectors to high- fidelity image outputs. It is found that the input latent space shows semantic correlations with the output image space. Recent works aim to interpret the latent space and discover meaningful directions that correspond to human interpretable image transformations. However, these methods either rely on explicit scores of attributes (e.g., memorability) or are restricted to binary ones (e.g., gender), which largely limits the applicability of editing tasks, especially for free- form artistic tasks like style/anime editing. In this paper, we propose an adversarial method, AdvStyle, for discovering interpretable directions …

Spatially-Invariant Style-Codes Controlled Makeup Transfer, Han Deng, Chu Han, Hongmin Cai, Guoqiang Han, Shengfeng He

Research Collection School Of Computing and Information Systems

Transferring makeup from the misaligned reference image is challenging. Previous methods overcome this barrier by computing pixel-wise correspondences between two images, which is inaccurate and computational-expensive. In this paper, we take a different perspective to break down the makeup transfer problem into a two-step extraction-assignment process. To this end, we propose a Style-based Controllable GAN model that consists of three components, each of which corresponds to target style-code encoding, face identity features extraction, and makeup fusion, respectively. In particular, a Part-specific Style Encoder encodes the component-wise makeup style of the reference image into a style-code in an intermediate latent space …

Ultrapin: Inferring Pin Entries Via Ultrasound, Liu, Ximing, Robert H. Deng, Robert H. Deng

Research Collection School Of Computing and Information Systems

While PIN-based user authentication systems such as ATM have long been considered to be secure enough, they are facing new attacks, named UltraPIN, which can be launched from commodity smartphones. As a target user enters a PIN on a PIN-based user authentication system, an attacker may use UltraPIN to infer the PIN from a short distance (50 cm to 100 cm). In this process, UltraPIN leverages smartphone speakers to issue human-inaudible ultrasound signals and uses smartphone microphones to keep recording acoustic signals. It applies a series of signal processing techniques to extract high-quality feature vectors from low-energy and high-noise signals …

Incorrectness Logic For Graph Programs, Christopher M. Poskitt

Research Collection School Of Computing and Information Systems

Program logics typically reason about an over-approximation of program behaviour to prove the absence of bugs. Recently, program logics have been proposed that instead prove the presence of bugs by means of under-approximate reasoning, which has the promise of better scalability. In this paper, we present an under-approximate program logic for a nondeterministic graph programming language, and show how it can be used to reason deductively about program incorrectness, whether defined by the presence of forbidden graph structure or by finitely failing executions. We prove this 'incorrectness logic' to be sound and complete, and speculate on some possible future applications …

Catch You With Cache: Out-Of-Vm Introspection To Trace Malicious Executions, Chao Su, Xuhua Ding, Qinghai Zeng

Research Collection School Of Computing and Information Systems

Out-of-VM introspection is an imperative part of security analysis. The legacy methods either modify the system, introducing enormous overhead, or rely heavily on hardware features, which are neither available nor practical in most cloud environments. In this paper, we propose a novel analysis method, named as Catcher, that utilizes CPU cache to perform out-of-VM introspection. Catcher does not make any modifications to the target program and its running environment, nor demands special hardware support. Implemented upon Linux KVM, it natively introspects the target's virtual memory. More importantly, it uses the cache-based side channel to infer the target control flow. To …

Iquant: Interactive Quantitative Investment Using Sparse Regression Factors, Xuanwu Yue, Qiao Gu, Deyun Wang, Huamin Qu, Yong Wang

Research Collection School Of Computing and Information Systems

The model-based investing using financial factors is evolving as a principal method for quantitative investment. The main challenge lies in the selection of effective factors towards excess market returns. Existing approaches, either hand-picking factors or applying feature selection algorithms, do not orchestrate both human knowledge and computational power. This paper presents iQUANT, an interactive quantitative investment system that assists equity traders to quickly spot promising financial factors from initial recommendations suggested by algorithmic models, and conduct a joint refinement of factors and stocks for investment portfolio composition. We work closely with professional traders to assemble empirical characteristics of “good” factors …

Hpress: A Hardware-Enhanced Proxy Re-Encryption Scheme Using Secure Enclave, Fan Zhang, Ziyuan Liang, Cong Zuo, Jun Shao, Jianting Ning, Jun Sun, Joseph K. Liu, Yibao Bao

Research Collection School Of Computing and Information Systems

Proxy re-encryption (PRE) allows a proxy to transform one ciphertext to another under different encryption keys while keeping the underlying plaintext secret. Because of the ciphertext transformability of PRE, there are many potential private communicating applications of this feature. However, existing PRE schemes are not as full-fledged as expected. The lack of necessary features makes them hard to apply in real-world scenarios. So far, there does not exist a unidirectional multihop PRE scheme with constant decryption efficiency and constant ciphertext size without extensions. Impractical performance and weak scalability also hinder PRE from most real-world applications. In this work, we present …

Marrying Top-K With Skyline Queries: Relaxing The Preference Input While Producing Output Of Controllable Size, Kyriakos Mouratidis, Keming Li, Bo Tang

Research Collection School Of Computing and Information Systems

The two most common paradigms to identify records of preference in a multi-objective setting rely either on dominance (e.g., the skyline operator) or on a utility function defined over the records’ attributes (typically, using a top-�� query). Despite their proliferation, each of them has its own palpable drawbacks. Motivated by these drawbacks, we identify three hard requirements for practical decision support, namely, personalization, controllable output size, and flexibility in preference specification. With these requirements as a guide, we combine elements from both paradigms and propose two new operators, ORD and ORU. We perform a qualitative study to demonstrate how they …

Japanese Monetary Policy And Its Impact On Stock Market Implied Volatility During Pleasant And Unpleasant Weather, Marinela Adriana Finta

Research Collection Lee Kong Chian School Of Business

We investigate the effect of Japan's Monetary Policy Meeting releases on the intraday dynamics of the Nikkei Stock Average Volatility Index and its futures during pleasant and unpleasant weather. We show that at the time of a monetary policy release when the temperature is pleasant, there is a significant decline in Japanese equities' implied volatility and futures, which lasts for about 10 min and 5 min, respectively. This decline is longer and exhibits a greater variation when releases occur during cold days. Finally, we emphasize the achievable economic profits and losses, given the reaction of Nikkei VI futures to the …

Analytics For Hospital Resource Planning: Two Case Studies, Jingui Xie, Weifen Zhuang, Marcus Ang, Mabel C. Chou, Li Luo, David D. Yao

Research Collection Lee Kong Chian School Of Business

Using real data and process flows from two large hospitals (in Singapore and in Chengdu, China) as cases, we illustrate how to apply certain modeling and optimization techniques, along with simulation as a validation tool, to hospital resource planning problems. We demonstrate how these simple analytical tools can help achieve significant improvements in both patient service and resource utilization, and without the need to increase the overall level of existing capacities. Two resource planning problems are studied in detail, one concerns the re-balancing of bed capacities among various wards, and the other addresses the allocation of medical diagnostic resource among …

On Factor Models With Random Missing: Em Estimation, Inference, And Cross Validation, Sainan Jin, Ke Miao, Liangjun Su

Research Collection School Of Economics

We consider the estimation and inference in approximate factor models with random missing values. We show that with the low rank structure of the common component, we can estimate the factors and factor loadings consistently with the missing values replaced by zeros. We establish the asymptotic distributions of the resulting estimators and those based on the EM algorithm. We also propose a cross validation-based method to determine the number of factors in factor models with or without missing values and justify its consistency. Simulations demonstrate that our cross validation method is robust to fat tails in the error distribution and …

Internal Capital Markets And Return Predictability In Complex Ownership Firms, Angelica Gonzalez, Sergei Sarkissian, Jun Tu, Ran Zhang

Research Collection Lee Kong Chian School Of Business

Using global cross-ownership data, we find return predictability for four possible cases in ownership-linked firms (OLFs): subsidiary−parent, parent−subsidiary, subsidiary−subsidiary, and parent−parent. A long/short portfolio strategy sorted by the lagged monthly returns of OLFs yields the monthly Fama-French six-factor alpha of 79−113 bps. These results, which are observed only after the establishment of ownership links, are not subsumed by industry or cross-country momentums or by alternative inter-firm relations, including customer−supplier links, strategic alliances, common boards, and shared analyst coverage. The OLF return predictability is best explained by active internal capital markets—a mechanism unique to firms with a complex ownership network.

Smart Contract Security: A Practitioners' Perspective, Zhiyuan Wan, Xin Xia, David Lo, Jiachi Chen, Xiapu Luo, Xiaohu Yang

Research Collection School Of Computing and Information Systems

Smart contracts have been plagued by security incidents, which resulted in substantial financial losses. Given numerous research efforts in addressing the security issues of smart contracts, we wondered how software practitioners build security into smart contracts in practice. We performed a mixture of qualitative and quantitative studies with 13 interviewees and 156 survey respondents from 35 countries across six continents to understand practitioners' perceptions and practices on smart contract security. Our study uncovers practitioners' motivations and deterrents of smart contract security, as well as how security efforts and strategies fit into the development lifecycle. We also find that blockchain platforms …

An Empirical Study Of The Landscape Of Open Source Projects In Baidu, Alibaba, And Tencent, Junxiao Han, Shuiguang Deng, David Lo, Chen Zhi, Jianwei Yin, Xin Xia

Research Collection School Of Computing and Information Systems

Open source software has drawn more and more attention from researchers, developers and companies nowadays. Meanwhile, many Chinese technology companies are embracing open source and choosing to open source their projects. Nevertheless, most previous studies are concentrated on international companies such as Microsoft or Google, while the practical values of open source projects of Chinese technology companies remain unclear. To address this issue, we conduct a mixed-method study to investigate the landscape of projects open sourced by three large Chinese technology companies, namely Baidu, Alibaba, and Tencent (BAT). We study the categories and characteristics of open source projects, the developer's …

Unveiling The Mystery Of Api Evolution In Deep Learning Frameworks: A Case Study Of Tensorflow 2, Zejun Zhang, Yanming Yang, Xin Xia, David Lo, Xiaoxue Ren, John C. Grundy

Research Collection School Of Computing and Information Systems

API developers have been working hard to evolve APIs to provide more simple, powerful, and robust API libraries. Although API evolution has been studied for multiple domains, such as Web and Android development, API evolution for deep learning frameworks has not yet been studied. It is not very clear how and why APIs evolve in deep learning frameworks, and yet these are being more and more heavily used in industry. To fill this gap, we conduct a large-scale and in-depth study on the API evolution of Tensorflow 2, which is currently the most popular deep learning framework. We first extract …