Wee Keong Ng

Wee Keong Ng
Nanyang Technological University | ntu · School of Computer Science and Engineering

PhD

About

452
Publications
69,019
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7,899
Citations
Citations since 2017
29 Research Items
3153 Citations
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20172018201920202021202220230100200300400500
20172018201920202021202220230100200300400500
Introduction

Publications

Publications (452)
Chapter
In a convolution neural network, a composition of linear scalar product, non-linear activation function and maximum pooling computations are intensively invoked. As such, to design and implement privacy-preserving, high efficiency machine learning mechanisms, one highly demands a practical crypto tool for secure arithmetic computations. SPDZ, an in...
Chapter
SPDZ, the nickname of secure multi-party computation (MPC) protocol of Damgård et al. from Crypto 2012, is an elegant secret value splitting technique which enjoys highly scalable and efficient multiplications with the help of off-line Beaver (multiplicative) triples. Since an arithmetic circuit defined over a finite field can be implemented by add...
Preprint
Full-text available
Oblivious data processing has been an on and off topic for the last decade or so. It provides great opportunities for secure data management and processing, especially in the cloud. At the same time, modern computing resources seem to be affordable enough to allow for practical use of homomorphic cryptography. Yet, the availability of products that...
Chapter
Full-text available
Banks provide interactive money withdrawal/payment facilities, such as ATM, debit and credit card systems. With these systems, customers could withdraw money and make payments without visiting a bank. However, traditional ATM, debit and credit card systems inherit several weaknesses such as limited ATM facilities in rural areas, the high initial co...
Chapter
Full-text available
The COVID-19 pandemic in 2020 has resulted in increased fatality rates across the world and has stretched the resources in healthcare facilities. There have been several proposed efforts to contain the spread of the virus among humans. Some of these efforts involve appropriate social distancing in public places, monitoring and tracking temperature...
Chapter
Full-text available
Existing blockchain smart contract platforms are designed as monolithic architectures. Even though there are multiple smart contracts with fully independent business logic, they run on a single monolithic container. This dependence on a monolithic container can be a performance bottleneck during the processing of a large number of transactions. To...
Article
Full-text available
Data privacy is an important issue for organizations and enterprises to securely outsource data storage, sharing, and computation on clouds / fogs. However, data encryption is complicated in terms of the key management and distribution; existing secure computation techniques are expensive in terms of computational / communication cost and therefore...
Preprint
Full-text available
Data privacy is an important issue for organizations and enterprises to securely outsource data storage, sharing, and computation on clouds / fogs. However, data encryption is complicated in terms of the key management and distribution; existing secure computation techniques are expensive in terms of computational / communication cost and therefore...
Article
Full-text available
This paper studies privacy-preserving weighted federated learning within the secret sharing framework, where individual private data is split into random shares which are distributed among a set of pre-defined computing servers. The contribution of this paper mainly comprises the following four-fold: • In the first fold, the relationship between fe...
Article
Full-text available
Existing blockchain smart contract platforms are designed as monolithic architectures. Even though there are multiple smart contracts with fully independent business logic, they run on a single monolithic container. This dependence on a monolithic container can be a performance bottleneck during the processing of a large number of transactions. To...
Chapter
Full-text available
Blockchain is a form of a distributed storage system that stores a chronological sequence of transactions in a tamper-evident manner. Due to the decentralized trust ecosystem in blockchain, various industries have adopted blockchain to build their applications. This paper presents a novel approach to building a blockchain-based document archive sto...
Chapter
In private, permissioned blockchains, organizations desire to transact with one another in a privacy-aware manner. For instance, when Alice sends X crypto-tokens to Bob at time t, it is desirable for Alice and Bob to perform double-spending check without revealing each other’s token balance. This also illustrates the fact that some input data from...
Chapter
Full-text available
Smart contract is a programming interface to interact with the underlying blockchain storage models. It is a database abstraction layer for blockchain. Existing smart contract platforms follow the imperative style programming model since states are shared. As a result, there is no concurrency control mechanism when executing transactions, resulting...
Article
Full-text available
The business model of Groupon has been categorized by many to be a case of daily deals or discount offerings to consumers. It is static (not responsive to business fluctuations and demands) and operates in batch mode (period-based availability). “Groupon Now” was proposed to be distinct from Groupon in that Groupon Now is dynamic and real-time. Gro...
Conference Paper
Full-text available
ASEAN region is currently in a unique position from the perspective of air traffic management. It comprises a large amount of independent states with limited collaboration between air traffic regulators; large aquatic zones often make air travel the only viable option, creating high demand for denser air traffic; on the other hand, there is low vis...
Preprint
Full-text available
Tensor network decomposition, originated from quantum physics to model entangled many-particle quantum systems , turns out to be a promising mathematical technique to efficiently represent and process big data in parsimonious manner. In this study, we show that tensor networks can systematically partition structured data, e.g. color images , for di...
Preprint
Path planning is important for the autonomy of Unmanned Aerial Vehicle (UAV), especially for scheduling UAV delivery. However, the operating environment of UAVs is usually uncertain and dynamic. Without proper planning, collisions may happen where multiple UAVs are congested. Besides, there may also be temporary no-fly zone setup by authorities tha...
Article
Concept drift is the problem that the statistical properties of the data generating process change over time. Recently, the Time Decaying Adaptive Prediction (TDAP) algorithm¹ was proposed to address the problem of concept drift. TDAP was designed to account for the effect of drifting concepts by discounting the contribution of previous learning ex...
Conference Paper
Robust learning of mixture models in high dimensions remains an open challenge and especially so in current big data era. This paper investigates twelve variants of hybrid mixture models that combine the G-means clustering, Gaussian, and Student t-distribution mixture models for high-dimensional predictive modeling and anomaly detection. High-dimen...
Conference Paper
Nowadays, the number of new malware samples discovered every day is in millions, which undermines the effectiveness of the traditional signature-based approach towards malware detection. To address this problem, machine learning methods have become an attractive and almost imperative solution. In most of the previous work, the application of machin...
Conference Paper
Full-text available
Unmanned air traffic management system (UTMS) and the ecosystem around it can be viewed as a large, complex, loosely-coupled cyber-physical system with flows of digital and analog data, sensors that collect data, and actuators that act upon data. As such, the ecosystem has a large cyber-attack surface, which, if penetrated, can cause serious damage...
Conference Paper
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Interacting with images through social media has become widespread due to ubiquitous Internet access and multimedia enabled devices. Through images, users generally present their daily activities, preferences or interests. This study aims to identify the way and extent to which personality differences, measured using the Big Five model, are related...
Conference Paper
Full-text available
Unmanned aircraft are quickly gaining credibility as an efficient tool for a wide range of tasks. With the increase in the amount of UAVs in the sky, the need for the UAV traffic management arises. Unmanned air traffic management system (UTMS), especially in the urban airspace, could be considered as a critical infrastructure, which—if disrupted—ca...
Technical Report
Full-text available
Cyber security is a concern for any country's critical infrastructures, digital or physical. With the aspiration to valorize Singapore's controlled airspace by allowing unmanned aerial vehicles to engage in civilian and commercial activities, cyber security concerns must be extended to this new form of critical infrastructure. As UTM and UAS in an...
Conference Paper
The fast growth of the cyberspace in recent years has served as a convenient channel for criminals to do their illegal businesses, especially in Dark Web - the hidden side of the Internet. The anonymous nature of Dark Web forums makes them ideal environments for criminal discussions. Ranging from government, security agencies to financial instituti...
Conference Paper
Outsourcing the data to the clouds offers an opportunity to drastically reduce costs of storing and processing data. On the other hand, it deprives the data owners of direct control over their data and that introduces new privacy risks. Data encryption has been introduced to tackle the data confidentiality issue. However, data encryption also bring...
Conference Paper
We notice, in our experiments with three malware samples of Darkcomet, Andromeda, and Zeus, that all three of them generate highly periodic network traffic. In addition, while there are a few works on intrusion detection which are based on this periodic behavior of malware, the prevalence of this behavior among the malware families in the wild is u...
Conference Paper
Full-text available
Recommending content to users involves understanding a) what to present and b) how to present them, so as to increase quality of experience (QoE) and thereby, content consumption. This work attempts to address the question of how to present contents in a way so that the user finds it easy to get to desired content. While the process of User Interfa...
Conference Paper
Privacy preserving association rule mining can extract important rules from distributed data with limited privacy breaches. Protecting privacy in incremental maintenance for distributed association rule mining is necessary since data are frequently updated. In privacy preserving data mining, scanning all the distributed data is very costly. This pa...
Conference Paper
Full-text available
Oblivious data processing has a potential to make an extremely significant impact on the whole landscape of data processing, specifically in scenarios that could be classified as big data. Recent developments in the area of fully homomorphic cryptography make oblivious data processing much more realistic. However, performance implications could ren...
Conference Paper
Full-text available
Database-as-a-Service is offered by many cloud service providers and could significantly reduce the IT infrastructure maintenance bills for enterprises. However, many hesitate migrating their data storage and processing to the cloud, and one of the reasons are data security issues. Encryption could provide sound security guarantees, but existing ap...
Article
The semantic network is a form of knowledge that represents various relationships between concepts with ambiguity. The knowledge can be employed to identify semantically related objects. It helps, for example, a recommender system to generate effective recommendations to the users.We propose to study a new semantic network, namely, the Concept Rela...
Conference Paper
Full-text available
Subjectivity detection can prevent a sentiment classifier from considering irrelevant or potentially misleading text. Since, different attributes may correspond to different opinions in the lexicon of different languages, we resort to multiple kernel learning (MKL) to simultaneously optimize the different modalities. Previous approaches to MKL for...
Article
Web search query suggestion is an important functionality that facilitates information seeking of search engine users. In existing work, the concepts of diversification and personalization have been individually introduced to query suggestion systems. In this paper, we propose a new query suggestion paradigm, Query Suggestion With Diversification a...
Article
Full-text available
Locality-Sensitive Hashing (LSH) and its variants are the well-known indexing schemes for the c-Approximate Nearest Neighbor (c-ANN) search problem in high-dimensional Euclidean space. Traditionally, LSH functions are constructed in a query-oblivious manner in the sense that buckets are partitioned before any query arrives. However, objects closer...
Article
In recent years, topic modeling is gaining significant momentum in information retrieval (IR). Researchers have found that utilizing the topic information generated through topic modeling together with traditional TF-IDF information generates superior results in document retrieval. However, in order to apply this idea to real-life IR systems, some...
Conference Paper
Full-text available
With high and growing supply of Database-as-a-Service solutions from cloud platform vendors, many enterprises still show moderate to low demand for them. Even though migration to a DaaS solution might result in a significantly reduced bill for IT maintenance, data security and privacy issues are among the reasons of low popularity of these services...
Article
Amplified and disrupting cyber-attacks might lead to severe security incidents with drastic consequences such as large property damage, sensitive information breach, or even disruption of the national economy. While traditional intrusion detection and prevention system might successfully detect low or moderate levels of attack, the cooperation amon...
Conference Paper
With the push of cloud computing which has both resource and compute scalability, data, which has been exploding in the past years, are often outsourced to a server. To this end, secure and efficient data processing and mining on outsourced private database becomes a primary concern for users. Among different secure data mining and machine learning...
Conference Paper
Rule mining, for discovering valuable relations between items in large databases, has been a popular and well researched method for years. However, such old but important technique faces huge challenges and difficulties in the era of cloud computing although which affords both storage and computing scalability: 1) data are outsourced to a cloud due...
Article
Expert finding for question answering is a challenging problem in community-based question answering (CQA) systems, arising in many real applications such as question routing and identification of best answers. In order to provide high-quality experts, many existing approaches learn the user model from their past question-answering activities in CQ...
Article
Understanding the users’ latent intents behind the search queries is critical for search engines. Hence, there has been an increasing attention on studying how to effectively mine the intents of search queries by analyzing search engine query log. However, we observe that the information richness of query log is not fully utilized so far and the in...
Conference Paper
Full-text available
Pioneered by Google's Pregel, various distributed graph computing systems have been developed in recent years for processing large real-world graphs such as social networks and web graphs. These systems employ the ``think like a vertex'' programming paradigm, where a program proceeds in iterations and at each iteration, vertices exchange messages w...
Article
Full-text available
Finding an optimal meeting point (OMP) for a group of people (or a set of objects) at different locations is an important problem in spatial query processing. There are many real-life applications related to this problem, such as determining the location of a conference venue, deciding the pick-up location of a tourist bus, and planing tactics of a...
Article
Feature selection is a challenging problem for high dimensional data processing, which arises in many real applications such as data mining, information retrieval, and pattern recognition. In this paper, we study the problem of unsupervised feature selection. The problem is challenging due to the lack of label information to guide feature selection...
Conference Paper
Full-text available
With the increasing popularity of cloud computing, security in cloud-based applications is gaining awareness and is regarded as one of the most crucial factors for the long term success of such applications. Despite all benefits of cloud computing, its fate lies in its success in gaining trust from its users achieved by ensuring cloud services bein...
Article
Full-text available
Nowadays, with the advance of technology, many applications generate huge amounts of data streams at very high speed. Examples include network traffic, web click streams, video surveillance, and sensor networks. Data stream mining has become a hot research topic. Its goal is to extract hidden knowledge/patterns from continuous data streams. Unlike...
Article
Full-text available
Microblogging platforms, such as Twitter, have already played an important role in recent cultural, social and political events. Discovering latent topics from social streams is therefore important for many downstream applications, such as clustering, classification or recommendation. However, traditional topic models that rely on the bag-of-words...
Conference Paper
Organizations and individuals nowadays face increasing daily operations closely rely on a huge amount of private data which is outsourced to a centralized server. Secure and efficient data processing and mining on such outsourced private data becomes a primary concern for users, especially with the push of cloud computing which has both resource an...
Article
Full-text available
Given a database of trajectories and a set of query locations, location-based trajectory search finds trajectories in the database that are close to all the query locations. Location-based trajectory search has many applications such as providing reference routes for travelers who are planning a trip to multiple places of interest. However, previou...
Conference Paper
Full-text available
Graphs in real life applications are often huge, such as the Web graph and various social networks. These massive graphs are often stored and processed in distributed sites. In this paper, we study graph algorithms that adopt Google's Pregel, an iterative vertex-centric framework for graph processing in the Cloud. We first identify a set of desirab...
Conference Paper
Full-text available
The rapid growth in the volume of many real-world graphs (e.g., social networks, web graphs, and spatial networks) has led to the development of various vertex-centric distributed graph computing systems in recent years. However, real-world graphs from different domains have very different characteristics, which often create bottlenecks in vertex-c...
Article
The rapid growth in the volume of many real-world graphs (e.g., social networks, web graphs, and spatial networks) has led to the development of various vertex-centric distributed graph computing systems in recent years. However, real-world graphs from different domains have very different characteristics, which often create bottlenecks in vertex-c...
Conference Paper
Full-text available
The vast amount of real-time and social content in microblogs results in an information overload for users when searching microblog data. Given the user's search query, delivering content that is relevant to her interests is a challenging problem. Traditional methods for personalized Web search are insufficient in the microblog domain, because of t...
Conference Paper
Full-text available
Software released to the user has the risk of reverse engineering attacks. Software control flow obfuscation is one of the techniques used to make the reverse engineering of software programs harder. Control flow obfuscation, obscures the control flow of the program so that it is hard for an analyzer to decode the logic of the program. In this pape...
Conference Paper
Full-text available
Even though the concept of a Database-as-a-Service (DaaS) is becoming more popular and offers significant expenditure cuts, enterprises are still reluctant to migrate their data storing and processing to the cloud. One of the reasons to that is a lack of solid security guarantees. Encrypted database is one of the major approaches to address the sec...
Article
Full-text available
Data uncertainty is inherent in many real-world applications such as environmental surveillance and mobile tracking. In particular, mining sequential patterns from inaccurate data, such as those data arising from sensor readings and GPS trajectories, is important for discovering hidden knowledge in such applications. In this paper, we propose to me...
Conference Paper
Web search involves voluminous data streams that record millions of users' interactions with the search engine. Recently latent topics in web search data have been found to be critical for a wide range of search engine applications such as search personalization and search history warehousing. However, the existing methods usually discover latent t...
Conference Paper
Reachability refers to the ability to get from one vertex to another within a graph. In this paper, we investigate the reachability problem on a distributed graph. We consider the scenario where there are two parties, each in possession of a private set of edges, while the vertices are public. The two parties wish to securely determine whether two...
Article
Ranking documents in terms of their relevance to a given query is fundamental to many real-life applications such as information retrieval and recommendation systems. Extensive study in these application domains has given rise to the development of many efficient ranking models. While most existing research focuses on developing learning to rank (L...
Conference Paper
Query suggestion is an important functionality provided by the search engine to facilitate information seeking of the users. Existing query suggestion methods usually focus on recommending queries that are the most relevant to the input query. However, such relevance-oriented strategy cannot effectively handle query uncertainty, a common scenario t...