Dah Ming Chiu

Dah Ming Chiu
The Chinese University of Hong Kong | CUHK · Department of Information Engineering

PhD, Harvard

About

225
Publications
40,164
Reads
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11,978
Citations
Citations since 2016
33 Research Items
3563 Citations
20162017201820192020202120220100200300400500600
20162017201820192020202120220100200300400500600
20162017201820192020202120220100200300400500600
20162017201820192020202120220100200300400500600
Additional affiliations
August 2009 - July 2015
The Chinese University of Hong Kong
Position
  • Head of Department
Education
September 1975 - May 1980
Harvard University
Field of study
  • Applied Mathematics

Publications

Publications (225)
Preprint
We consider the problem of representation learning for temporal interaction graphs where a network of entities with complex interactions over an extended period of time is modeled as a graph with a rich set of node and edge attributes. In particular, an edge between a node-pair within the graph corresponds to a multi-dimensional time-series. To ful...
Article
Full-text available
Ride-on-demand (RoD) services use dynamic prices to balance the supply and demand to benefit both drivers and passengers, as an effort to improve service efficiency. However, dynamic prices also create concerns for passengers: the “unpredictable” prices sometimes prevent them from making quick decisions at ease. It is thus necessary to give passeng...
Article
As online video service continues to grow in popularity, video content providers compete hard for more eyeball engagement. Some users visit multiple video sites to enjoy videos of their interest while some visit exclusively one site. However, due to the isolation of data, mining and exploiting user behaviors in multiple video websites remain unexpl...
Preprint
Rapid and massive adoption of mobile/ online payment services has brought new challenges to the service providers as well as regulators in safeguarding the proper uses such services/ systems. In this paper, we leverage recent advances in deep-neural-network-based graph representation learning to detect abnormal/ suspicious financial transactions in...
Article
Recent years have witnessed the rapidly-growing business of ride-on-demand (RoD) services such as Uber, Lyft and Didi. Unlike taxi services, these emerging transportation services use dynamic pricing to manipulate the supply and demand, and to improve service responsiveness and quality. Despite this, on the drivers' side, dynamic pricing creates a...
Article
In this paper, we study the posting behavior of online social network (OSN) users, in particular the posting frequency and temporal patterns, and consider possible interpretations of how users use the platform. At the aggregate (macro) level, we find two distinct peaks of traffic, one during morning working hours, and one in the evening. The mornin...
Conference Paper
Ride-on-demand (RoD) services such as Uber and Didi (in China) are becoming increasingly popular, and in these services dynamic price plays an important role in balancing the supply (i.e., the number of cars) and demand (i.e., the number of passenger requests) to benefit both drivers and passengers. However, the dynamic price also creates concerns...
Chapter
In past studies, Online Social Networks (OSNs) is commonly assumed to build on triadic closure, implying that alters in a user’s ego network form either a single connected component, or a small number of connected components. In real-world OSNs, we find a significant number of users with a different ego network pattern consisting of a more diverse...
Article
Full-text available
Ride-on-demand (RoD) services such as Uber and Didi are becoming increasingly popular, and in these services dynamic prices play an important role in balancing the supply and demand to benefit both drivers and passengers. However, dynamic prices also create concerns. For passengers, the "unpredictable" prices sometimes prevent them from making quic...
Conference Paper
The streaming of panoramic videos comes with a new challenge: adapting the streamed content to user attention. In this paper, by making some abstraction we study the key issues of the problem: (1) online content switching strategies, and (2) offline segmentation in preparation for adaptive streaming. Our work demonstrates how the problem depends fu...
Article
The academic community has seen a tremendous growth in number of authors and publications in recent times. Most previous studies of the academic community, whether on individual activity, productivity and influence, or collaboration patterns and their implications, have been based on a flat and static view of the system. However, the academic commu...
Conference Paper
In this paper, we study the posting behavior of OSN users, in particular the posting frequency and temporal patterns, and consider possible interpretations of how users use the platform. At the aggregate (macro) level, we find two distinct peaks, one during morning working hours, and one in the evening. The morning peak is more pronounced for frequ...
Article
In emerging ride-on-demand (RoD) services such as Uber and Didi (in China), dynamic prices play an important role in regulating supply and demand, trying to improve the service quality for both drivers and passengers. In this paper, we take a new perspective to study RoD services besides the supply or demand, and focus on passengers' reaction to dy...
Article
All large scale online video systems, e.g., Netflix and Youku, make a significant investment on video recommendations that can dramatically affect video information diffusion processes among users. However, there is a lack of efficient methodology to interpret how various recommendation mechanisms affect information diffusion processes resulting in...
Conference Paper
Full-text available
In emerging ride-on-demand (RoD) services such as Uber and Didi (in China), dynamic prices play an important role in regulating supply and demand, trying to improve the service quality for both drivers and passengers. In this paper, we take a new perspective to study RoD services besides the supply or demand, and focus on passengers’ reaction to dy...
Conference Paper
In emerging ride-on-demand (RoD) services such as Uber or Didi (in China), dynamic pricing plays an important role in regulating supply and demand, trying to make such service, to some extent, more convenient for passengers. Despite the convenience, dynamic pricing also exerts mental burden on passengers: they wonder whether the current price is lo...
Article
Video popularity is an essential reference for optimizing resource allocation and video recommendation in online video services. However, there is still no convincing model that can accurately depict a video's popularity evolution. In this paper, we propose a dynamic popularity model by modeling the video information diffusion process driven by var...
Conference Paper
As online video service continues to grow in popularity, video content providers compete hard for more eyeball engagement. Some users visit multiple video sites to enjoy videos of their interest while some visit exclusively one site. However, due to the isolation of data, mining and exploiting user behaviors in multiple video websites remain unexpl...
Article
Can the Internet evolve, and what is the direction of this evolution? This article offers a plausible model for Internet evolution, and explains its implications for different stakeholders.
Article
The net neutrality debate has been centered at the question: should Internet Service Providers (ISPs) be allowed to differentiate services for Internet content traffic? The concern is that the differentiation imposed by selfish ISPs might discriminate Content Providers (CPs) and harm social welfare. Although market competition among ISPs would alle...
Conference Paper
The installation of smart meters in buildings introduces new opportunities for system and application design, to encourage energy conservation or other environmentally friendly behaviors. Delivering feedback to users is a widely-adopted approach that can potentially influence behaviors effectively. The main contribution of our work includes designi...
Article
Full-text available
Video recommendation has become an essential part of online video services. Cold start, a problem relatively common in the practical online video recommendation service, occurs when the user who needs video recommendation has no viewing history. (Cold start consists of the new-user problem and the new-item problem. In this paper, we discuss the new...
Conference Paper
Video recommendation has become an essential part of online video services. Cold start, a problem relatively common in the practical online video recommendation service, occurs when the user who needs video recommendation has no viewing history (Cold start consists of the new-user problem and the new-item problem. In this paper, we discuss the new-...
Conference Paper
Citations serve as an important metric for identifying experts and opinion leaders in academic communities. In this paper, we analyze the evolution of yearly rankings of top-cited (C-list) authors in the domain of Computer Science. In searching for factors that help authors become top-cited, we also gather authors in the top-collaboration list (A-l...
Article
Full-text available
In this paper, we mine and learn to predict how similar a pair of users' interests towards videos are, based on demographic (age, gender and location) and social (friendship, interaction and group membership) information of these users. We use the video access patterns of active users as ground truth (a form of benchmark). We adopt tag-based user p...
Article
Full-text available
Academic publication metadata can be used to analyze the collaboration, productivity and hot topic trends of a research community. In this paper, we study a specific group of authors, namely the top active authors. They are defined as the top 1% authors with uninterrupted and continuous presence in scientific publications over a time window. We tak...
Article
Popular online video-on-demand (VoD) services all maintain a large catalog of videos for their users to access. The knowledge of video popularity is very important for system operation , such as video caching on content distribution network (CDN) servers. The video popularity distribution at a given time is quite well understood. We study how the v...
Article
We consider a peer-to-peer (P2P)-assisted video-on-demand (VoD) system where each peer can store a relatively small number of movies to offload the server when these movies are requested. User requests are stochastic based on some movie popularity distribution. The problem is how to replicate (or place) content at peer storage to minimize the serve...
Conference Paper
Promoting and practicing energy conservation requires a cost-effective system for monitoring electricity usage and a well-designed incentive policy to induce energy-saving habits. In this paper, we describe our experiences in building a smart meter system in campus dormitories and the design of an incentive policy. The smart meter system captures d...
Article
Crowdsourcing-based video service systems, e.g., Thunder Crystal, are novel content distribution platforms composed by a large number of agent devices, acting like miniservers. Most agents are normal Internet users who would like to earn rewarded cash by uploading content through their devices. Compared with CDN, the bandwidth cost is much cheaper;...
Conference Paper
Scientific literature till date can be thought of as a partially revealed landscape, where scholars continue to unveil hidden knowledge by exploring novel research topics. How do scholars explore the scientific landscape, i.e., choose research topics to work on? We propose an agent-based model of topic mobility behavior where scholars migrate acros...
Conference Paper
Academic publication metadata can be used to analyze the collaboration, productivity and hot topic trends of a research community. Recently, it is shown that authors with uninterrupted and continuous presence (UCP) over a time window, though small in number (about 1%), amass the majority of significant and high-influence academic output. We adopt t...
Article
We study the problem of managing high intradatacenter traffic in a chunk-based public cloud storage service. The high traffic volume is introduced by aggregating very large files from multiple chunk servers in a single edge server. We measure a commercial cloud storage service system, and observe that peak traffic volume overwhelms the network inte...
Article
Full-text available
In recent times, the academic ecosystem has seen a tremendous growth in number of authors and publications. While most temporal studies in this area focus on evolution of co-author and citation network structure, this systemic inflation has received very little attention. In this paper, we address this issue by proposing a population model for acad...
Article
Online video-on-demand(VoD) services invariably maintain a view count for each video they serve, and it has become an important currency for various stakeholders, from viewers, to content owners, advertizers, and the online service providers themselves. There is often significant financial incentive to use a robot (or a botnet) to artificially crea...
Article
Full-text available
Scientific literature till date can be thought of as a partially revealed landscape, where scholars keep unveiling hidden knowledge by exploring novel research topics. How do scholars explore the scientific landscape, i.e., choose research topics to work on? We propose an agent-based model of topic mobility behavior where scholars migrate across re...
Article
There are two types of P2P systems satisfying two different user demands: 1) file downloading and 2) video-on-demand (VoD) streaming. An example of file downloading is the original BitTorrent, and examples for VoD streaming include various commercial P2P-based VoD streaming systems such as that offered by PPLive. We have a hypothesis - by combining...
Article
Full-text available
Large Internet video delivery systems serve millions of videos to tens of millions of users on daily basis, via Video-on-Demand and live streaming. Video popularity evolves over time. It represents the workload, as welll as business value, of the video to the overall system. The ability to predict video popularity is very helpful for improving serv...
Article
Video streaming service in wireless networks is increasingly using dynamic selection of video bit-rates to provide a high quality of user experience (QoE). The bit-rate switching mechanism, performed at client side, plays a key role in determining QoE metrics. In this paper, we present the first analytical framework to compute starvation probabilit...
Article
P2P systems require neighbor peers to frequently exchange buffer-map (BM) messages for efficient content sharing and distribution, which, however, can result in considerable communication overhead. A big problem in the BMs exchanged between neighbor peers is that a lot of information in them is redundant. To reduce the redundancy, some P2P systems...
Article
Full-text available
Nowadays digital services, such as cloud computing and network access services, allow dynamic resource allocation and virtual resource isolation. This trend can create a new paradigm of flexible pricing schemes. A simple pricing scheme is to allocate multiple isolated service classes with differentiated prices, namely Paris Metro Pricing (PMP). The...
Patent
A system and a method for evaluating transport of data segments of media content bitstream over a peer-to-peer network by streaming data chunks of a media content through a peer-to-peer network, generating network transport distortion on the data chunks using live experiments, simulation, or artificial generation, determining a playback strategy of...
Article
Full-text available
A peer-to-peer (P2P) live streaming system faces a big challenge under flash crowds. When a flash crowd occurs, the sudden arrival of numerous peers may starve the upload capacity of the system, hurt its quality of service, and even cause system collapse. This paper provides a comprehensive study on the performance of P2P live streaming systems und...
Conference Paper
Popular online Video-on-Demand (VoD) services all maintain a large catalog of videos for their users to access. The number of servers assigned to serve each video is directly related to the relative popularity of the video. The distribution of popularity at a given time is quite well understood. We study how the video popularity changes over its li...
Conference Paper
Rapid growth in users of smartphones and other mobile devices is increasing the demand for online video service to these mobile devices. The mobile video on demand (VoD) service is almost exclusively provided by content delivery network (CDN) servers since mobile devices are not powerful enough to provide any peer-To-peer (P2P) service. However, in...
Article
Preferential Attachment (PA) models the scientific citation process. In the PA model, a new paper attaches itself to the citation network based only on the popularity of the currently existing papers. This invariably leads to a network whose degree distribution satisfies the Power Law. Yet, empirical results show that paper age should also play a r...
Article
By routing workload to locations with cheaper electricity, geographic load-balancing (GLB) has been shown a promising mechanism to cut down the electricity bill of geo-distributed datacenters operated by the same organization. Most existing studies on GLB assume that the use of GLB has no impact on electricity prices, even though GLB increases loca...
Article
A big portion of Internet traffic nowadays is video. A good understanding of user behavior in online Video-on-Demand (VoD) systems can help us design, configure and manage video content distribution. With the help of a major VoD service provider, we conducted a detailed study of user behavior watching streamed videos over the Internet. We engineere...
Conference Paper
The net neutrality debate has been centered at the question: whether price and service differentiation should be allowed for the Internet? We focus on a monopoly market, where regulation is often required, and study the type of service differentiation where an option of paid prioritization is provided for the Content Providers (CPs) by an Internet...
Article
Smart phones have become very popular. Most people attending a conference have a smartphone with them; so it is natural to think about how to build a mobile application to support a conference. In the process of organizing ACM Sigcomm 2013, we initiated a student project to build such a conference app. As a conference organizator, we had good motiv...
Article
Thousands of competing autonomous systems (ASes) must cooperate with each other to provide global Internet connectivity. Each AS has independent economic objectives and retains autonomy in setting their routing policies independently to maximize its profit. However, such autonomy enables ASes to produce conflicting routing polices and thus raises r...
Conference Paper
There are two types of P2P systems satisfying two different user demands: (a) file downloading and (b) VoD streaming. Example of (a) is the original BitTorrent, and examples for (b) including various commercial P2P-based VoD streaming systems such as that offered by PPLive. We have a hypothesis - by combining a type (a) system and a type (b) system...
Article
Full-text available
Online video-on-demand(VoD) services invariably maintain a view count for each video they serve, and it has become an important currency for various stakeholders, from viewers, to content owners, advertizers, and the online service providers themselves. There is often significant financial incentive to use a robot (or a botnet) to artificially crea...
Article
Full-text available
Peer-to-peer (P2P) streaming over Internet needs to consider the dynamic bandwidth fluctuations and various client device capabilities. To maximize the network utilization and to achieve stable P2P streaming, we propose a novel multi-layered P2P streaming system in which the scalable video bit-stream is fully decodable by legacy non-scalable video...
Patent
There is disclosed a method for replicating media contents in a P2P VoD system comprising a plurality of peers. The method may comprise: determining that a candidate media unit shall be replicated into a local storage of one of the peers; checking whether said local storage has enough space to store the candidate media unit; if not, selecting one m...
Conference Paper
Increasingly, Internet services are supported by a large-scale and distributed infrastructure on top of the Internet. This includes Content Delivery Networks (CDNs), Peer-to-peer (P2P) networks for content distribution, and more recently Cloud Computing built out of distributed data centers. Applications include Social networks (e.g. Facebook), con...
Article
When peer-to-peer (P2P) networks meet social networks (for instance, Facebook), the former develops new characteristics. A notable change is that peers would use real names in social networks, and hence the P2P networks become naturally clustered according to the human relationship imported from the social networks. Conceivably, social network theo...
Article
Practical video streaming systems all use some form of progressive downloading to let users download the video at a faster rate than the playback rate. Since users may quit before viewing the complete video, however, much of the downloaded video may be "wasted". To the extent that users' departure behavior can be predicted, smart progressive downlo...
Article
Full-text available
Through academic publications, the authors of these publications form a social network. Instead of sharing casual thoughts and photos (as in Facebook), authors pick co-authors and reference papers written by other authors. Thanks to various efforts (such as Microsoft Libra and DBLP), the data necessary for analyzing the academic social network is b...
Article
Full-text available
In bibliometrics studies, a common challenge is how to deal with incorrect or incomplete data. Given a large volume of data, however, there often exists certain relationships between data items that allow us to recover missing data items and correct erroneous data. In this paper, we study a particular problem of this sort - estimating the missing y...
Article
Full-text available
P2P streaming tries to achieve scalability (like P2P file distribution) and at the same time meet real-time playback requirements. It is a challenging problem still not well under-stood. In this paper, we describe a simple stochastic model that can be used to compare different downloading strategies with random peer selection.Based on this model, w...
Article
Video content downloading using the P2P approach is scalable, but does not always give good performance. Recently, subscription-based premium services have emerged, referred to as cloud downloading. In this service, the cloud storage and server caches user-interested content and updates the cache based on user downloading requests. If a requested v...
Article
Traditional video-on-demand (VoD) systems rely purely on servers to stream video content to clients, which does not scale. In recent years, peer-to-peer assisted VoD (P2P VoD) has proven to be practical and effective. In P2P VoD, each peer contributes some storage to store videos (or segments of videos) to help the video server. Assuming peers have...
Article
Location-specific Internet services are predicated on the ability to identify the geographic position of IP hosts accurately. Fundamental to current state-of-the-art geolocation techniques is reliance on heavyweight traceroute-like probes that put a ...
Article
Routing failures are common on the Internet and routing protocols can not always react fast enough to recover from them, which usually cause packet delivery failures. To address the problem, fast reroute solutions have been proposed to guarantee reroute path availability and to avoid high packet loss after network failures. However, existing soluti...
Conference Paper
Full-text available
Keywords of academic papers are jargons shared within a research domain as well as a summary of the contents. However, the increasing popularity of the interdisciplinary research in academia in recent years opened a possibility that the choice of keywords would be no longer confined by the traditional domain boundaries. In order to investigate the...
Article
Full-text available
We consider a P2P-assisted content storage and delivery system to support a streaming Video-on-Demand (VoD) service. In this system, the peers are part of the service provider (e.g. set-top boxes) with limited storage space. Servers with ample storage and bandwidth are deployed to guarantee the availability and quality, but it is desirable to minim...
Article
In recent years, Peer-to-Peer assisted Video-on-Demand (P2P VoD) has become an effective and efficient approach to distribute high-quality videos to large number of peers. In a P2P VoD system, each peer contributes storage to store several videos to help offload the server. The replication strategy, which determines the videos to be stored at each...
Article
Full-text available
In peer-to-peer (P2P) networks, incentive protocol is used to encourage cooperation among end-nodes so as to deliver a scalable and robust service. However, the design and analysis of incentive protocols have been ad hoc and heuristic at best. The objective of this paper is to provide a simple yet general framework to analyze and design incentive p...
Conference Paper
The Internet routing table size has been growing rapidly. In future Internet, if given a much larger public address space (e.g., IPv6), the potential expansion can be very significant, and the cost of a large routing table will affect many ISPs. Before devising methods to ensure routing scalability, it is necessary to understand what factors lead t...
Article
Full-text available
Content distribution via network coding has received a lot of attention lately. However, direct application of network coding may be insecure. In particular, attackers can inject "bogus” data to corrupt the content distribution process so as to hinder the information dispersal or even deplete the network resource. Therefore, content verification is...
Article
Full-text available
We consider a P2P-assisted Video-on-Demand (VoD) system where each peer can store a relatively small number of movies to offload the server when these movies are requested. User requests are stochastic based on some movie popularity distribution. The problem is how to replicate (or place) content at peer storage to minimize the server load. Several...
Conference Paper
Full-text available
Both content quality and market coverage have significant impacts on a network content provider's revenue. In this paper, we present a preliminary study on how providers' cooperation and adoption of special content can affect the content quality and market coverage. We first consider a baseline case, where providers have static contents and do not...