Victor W. K. Chan

Victor W. K. Chan
Tsinghua University | TH · Tsinghua-Berkeley Shenzhen Institute

Doctor of Philosophy

About

105
Publications
26,880
Reads
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973
Citations
Introduction
Research interests: big-data analytics, simulation (agent-based and discrete-event), social network analysis, optimization, and statistical analysis. >>> Application areas: healthcare, emergency response, transportation, facility layout, and manufacturing. >>> Current projects: enterprise big-data, multi-layered social networks, emergency planning, social influence, Chinese medicine and network pharmacology.

Publications

Publications (105)
Preprint
The three-dimensional bin packing problem (3D-BPP) plays an important role in city logistics and manufacturing environments, due to its direct relevance to operational cost. Most existing literature have investigated the conventional 3D-BPP, in which the shape of items are typically considered as regular shapes, e.g., rectangular-shaped rigid boxes...
Article
Information sharing systems are a critical component of emergency response—especially in campus attack situations that unfold very rapidly. The design of effective information sharing systems is often difficult, however, due to a lack of data on these assault events. This work takes an agent-based approach to simulate three campus emergency informa...
Article
Nowadays, fast delivery services have created the need for high-density warehouses. The puzzle-based storage system is a practical way to enhance the storage density, however, facing difficulties in the retrieval process. In this work, a deep reinforcement learning algorithm, specifically the Double&Dueling Deep Q Network, is developed to solve the...
Article
Full-text available
A critical problem in large neural networks is over parameterization with a large number of weight parameters, which limits their use on edge devices due to prohibitive computational power and memory/storage requirements. To make neural networks more practical on edge devices and real-time industrial applications, they need to be compressed in adva...
Chapter
Intuitively, the time series of each wave of COVID-19 can be partitioned into several stages with different dynamics, such as the early stage, the raising stage and the fading stage. However, it is still needed to define a mathematical standard to quantitatively distinguish one stage from another, instead of performing the segmentation subjectively...
Chapter
The outbreak of coronavirus disease 2019 (COVID-19) in China has seriously affected the health and daily life of Chinese people. To contain the epidemic, the government made emergency policies quickly, including large-scale social intervention. But the impact of social intervention is still unclear. As the epidemic is affecting other countries all...
Article
Full-text available
This study proposes a framework to diagnose stock market crashes and predict the subsequent price rebounds. Based on the observation of anomalous changes in stock correlation networks during market crashes, we extend the log-periodic power-law model with a metric that is proposed to measure network anomalies. To calculate this metric, we design a p...
Chapter
Data-driven methods are proposed to optimize both pricing and inventory management strategies in price and quantity setting newsvendor problem. Simulation experiments show that prescriptive method and casual sample average approximation outperform Predict-then-Optimize method. Sample average approximation might be even worse when ignoring pricing e...
Chapter
Additive Manufacturing (AM) technology could revolutionize the way industry makes products. However, there are still challenges that must be overcome since these are slowing down AM adoption by industry. Therefore, this research aims to uncover these limitations based on a systematic literature review. The findings of this study show that there are...
Chapter
Local energy markets (LEM’s) have emerged as an important factor in the development of energy systems which coordinate distributed and privately-owned generation resources. LEM’s may enable energy transactions between physically or virtually connected users (consumers and prosumers); local power system load balancing, increased energy system resili...
Article
Network pharmacology is a method to study the mechanism of a Traditional Chinese Medicine (TCM) prescription on a disease. However, most articles using network pharmacology to study the mechanism did not combine the weight information of herbs, the weight information of targets of disease, and the interaction information between targets together. W...
Preprint
Full-text available
Nowadays, fast delivery services have created the need for high-density warehouses. The puzzle-based storage system is a practical way to enhance the storage density, however, facing difficulties in the retrieval process. In this work, a deep reinforcement learning algorithm, specifically the Double&Dueling Deep Q Network, is developed to solve the...
Article
Full-text available
Abstract Traffic prediction on road networks is highly challenging due to the complexity of traffic systems and is a crucial task in successful intelligent traffic system applications. Existing approaches mostly capture the static spatial dependency relying on the prior knowledge of the graph structure. However, the spatial dependency can be dynami...
Chapter
This paper describes modeling strategies for risk prediction in clinical medicine, mainly with respect to survival analysis. Restricted data, which is commonly given in initial clinical research, is assumed for these strategies. Cox’s proportional hazard model is used with modern statistical approaches. In this paper, detailed modeling strategies f...
Chapter
Estimating the inter-city population flow is critical for modeling the spread of COVID-19. However, for most cities, it is difficult to extract accurate population numbers for inflow and outflow. On the other hand, mobile carriers and Internet companies can estimate the distribution of population flow by tracking their users; but their data only co...
Article
Full-text available
Reducing the number of operating vehicles in cities has enormous significance on mitigating traffic congestion and environment pollution. Ride-sharing is an efficient way to reduce fleet size in urban areas. In this work, we propose two integer programming models to qualify the benefits of ride-sharing on reducing fleet size. The proposed models ar...
Article
In recent decades, as machine learning is getting more and more popular in many fields, multiple classification methods have been proposed and applied to various applications for intelligent decision making. Most of the classification methods are just work on a shallow machine learning classifier. And many of these algorithms are already existed in...
Article
Full-text available
Efficient accurate Gaussian localization is an important topic in many applications, e.g. localization based super-resolution microscopy and image scanning microscopy, which requires large-scale Gaussian patterns localization for accurate super-resolution image reconstruction. Existing Gaussian localization methods usually require high signal-to-no...
Preprint
Full-text available
The safety of students worldwide remains a key issue during COVID-19. The reopening of universities in high risk countries during Fall 2020 resulted in numerous outbreaks. While regular screening and testing on campus can prevent the transmission of SARS-CoV-2, they are extremely challenging to implement due to various reasons such as cost and logi...
Article
Full-text available
The imbalanced distribution of shared bikes in the dockless bike-sharing system (a typical example of the resource-sharing system), which may lead to potential customer churn and lost profit, gradually becomes a vital problem for bike-sharing firms and their users. To resolve the problem, we first formulate the bike-sharing system as a Markovian qu...
Article
Full-text available
Accurate segmented mirror wavefront sensing and control is essential for next-generation large aperture telescope system design. In this paper, a direct tip–tilt and piston error detection technique based on model-based phase retrieval with multiple defocused images is proposed for segmented mirror wavefront sensing. In our technique, the tip–tilt...
Preprint
Full-text available
Although the dockless bike-sharing system, which can be regarded as a typical example of the resource-sharing system, has been increasingly popular for years with people especially in China, the imbalanced distribution of shared bikes gradually becomes a major problem for both bike-sharing companies and their customers. To solve the imbalance probl...
Article
Full-text available
In optical imaging systems, the aberration is an important factor that impedes realising diffraction-limited imaging. Accurate wavefront sensing and control play important role in modern high-resolution optical imaging systems nowadays. In this study, a simple model-based phase retrieval algorithm is proposed for accurate efficient wavefront sensin...
Article
Full-text available
Information sharing during emergency events often takes place through popular social messaging apps. An emergency response area of increasing concern in recent times is that of mass attacks on school campuses yet work studying information sharing systems in these situations is scarce. In this exploratory work, we used data from various sources to c...
Article
Full-text available
Although there are several special features in block-chain technology such as machine trust, traceability, and security, high energy consumption remains an issue in broadening the applications of block-chain technology. Some researchers proposed the use of proof of stake (PoS) mechanism rather than proof of work (PoW) mechanism to reduce energy con...
Article
Full-text available
Distributed renewable energy offers an exciting opportunity for sustainable transition and climate change mitigation. However, it is overlooked in most of the conventional tradable green certificates programs. Blockchain shows an advantage of incorporating a galaxy of distributed prosumers in a transparent and low-cost manner. This paper proposes I...
Article
Full-text available
Blockchain, as an emerging technology and a disruptive innovation, has attracted attention from both academia and industry. However, there are many potential risks associated with it, such as the technical risk, the legal risk and the privacy risk. A comprehensive risk analysis is crucial for cost-effective deployment of blockchain technology. Impo...
Chapter
Data privacy is of great importance for the healthy development of service systems. Companies and governments that provide services to people often have big concerns in sharing their data. Because of that, data must be preprocessed (e.g., anonymized) before they can be shared. However, without identification, it is difficult to match data from diff...
Chapter
WeChat social network is one of the most popular social platforms in China, providing not only communication services but also enabling a number of service innovations. Understanding how information diffuses in an online social network such as WeChat is critical to the design and evaluation of existing or new services. This paper studies the diffus...
Article
Full-text available
The joint uncertainties of wholesale price and end-user demand quantity often poses huge pricing challenges to energy retailers. However, the literature lacks analysis of such uncertainties’ impacts on retailer pricing behaviors and possible hedging behaviors. To study these impacts, this paper proposes four models: a risk-averse or a risk-neutral...
Article
This paper presents two semi-definite programming (SDP) based methods to solve the Key Player Problem (KPP). The KPP is to identify a set of k nodes (i.e., key players) from a social network of size n such that the number of nodes connected to these k nodes is maximized. The KPP has applications in social diffusion and products adoption as it helps...
Article
Full-text available
A manufacturing cost model is created that includes all labor, material and overhead costs for novel mycelium-based biocomposite sandwich structures produced by a commercial firm. This model is implemented through a spreadsheet to calculate the equivalent uniform annual costs (UAC) of all manufacturing facilities. A simulation model of the manufact...
Article
This study examines Gibrat’s law regarding size–growth relationships in the consumer-to-consumer (C2C) online marketplace. Using dynamic panel data models, we analyze 21,948 e-merchants from 14 industries on Taobao.com. The data analysis shows that Gibrat’s law holds for large and mature stores when their size and age exceed certain threshold, but...
Article
Full-text available
The study of service value networks adds a new dimension of investigation to industrial systems: human networks. Existing literature shows humans hyper-network to co-create value within and outside of the traditional structures of an organization or an extended enterprise – such as social networking for innovation and e-commerce for supply chain. S...
Article
This paper develops an agent-based discrete-event simulation (AB-DES) modelling framework for transportation evacuation by integrating an event scheduling scheme into an agent-based method. This framework has a unique hybrid simulation space that includes a continuous space and a flexible-structured network. This hybrid space overcomes the cellular...
Article
Full-text available
Wireless medium access control (MAC) protocols usually provide reliability in the presence of packet errors. The efficiency of these reliability mechanisms is generally low since they require the entire packet to be retransmitted even though only parts of it may have been corrupted. To address this issue, this paper presents an efficient mechanism...
Conference Paper
Full-text available
Linear programming representations for discrete-event simulation provide an alternative approach for analyzing discrete-event simulations. This paper presents several formulations for G/G/m queues and discusses the applications and limitations of these formulations. We derive the relationship between these formulations. We then demonstrate the appl...
Conference Paper
This paper studies the size distribution of hospitals and its underlying generative mechanisms. Based on the U.S. hospital data, we find that the size distribution is sub-lognormal (a leptokurtic distribution more skewed than normal but less skewed than lognormal). This distribution is different from those of firms and cities. We develop an agent-b...
Article
The deregulation and restructuring of electricity markets have created a variety of challenging research problems. In addition, due to the complexity of electricity markets, most of these research problems are not amenable to analytical methods. Agent-based simulation is an approach for simulating and analyzing complex systems with interacting auto...
Article
This paper considers the competition of service centers within a service system. Each service center is modeled as a multiple-server queue. Service centers compete with each other in a fair manner and adjust their service resources number of servers to accommodate the demand obtained from the competition. An agent-based approach is used to model th...
Article
The effectiveness of Monte Carlo simulation relative to intelligent search strategies for solving block layout problems is investigated. For testing purposes, 810 block layout problems are constructed to span a wide range of problem sizes, material flow variation levels, work centre space requirements distributions, and work centre shape distributi...
Chapter
mijs : the expected volume of material flow between workcenters i and j within material flow scenario s, in unit handling loads per unit time, for i, j = 1,...,n and s = 1,...,S, The robust procedure described in Section 3 is used to solve this dynamic line layout problem with nonlinear materials handling costs and unequal work centers areas. The e...
Article
Full-text available
Agent-based simulation (ABS) has been widely regarded as a powerful tool for modelling complex systems involving a number of interacting autonomous agents. One major criticism of the ABS approach is that its analytical property is weak or intractable. This creates obstacles for researchers and practitioners to mathematically analyze simulation outp...
Conference Paper
Full-text available
There are two causes of packet losses during a wireless transmission: losses caused by collisions and losses caused by poor channel conditions. The throughput and spatial reuse of IEEE 802.11 based wireless networks, as well as the effectiveness of the rate adaptation algorithms they use, is adversely affected by their inability to determine the re...
Article
Full-text available
Service is about value cocreation between customers and providers. Cocreation builds on human networking: people connecting fluidly with each other as customers, providers, and resources to pursue common values. This paper develops a new analysis of service value networks, building on a previously presented hyper-network model to study how people c...
Article
Full-text available
Service is about value cocreation between customers and providers. Cocreation builds on human networking: people connecting fluidly with each other as customers, providers, and resources to pursue common values. This paper develops a new analysis of service value networks, building on a previously presented hypernetwork model to study how people ca...
Article
Full-text available
This paper presents an agent-based discrete-event simulation (AB-DES) modeling approach for transportation evacuation simulation based on a hybrid continuous and cell space. This approach combines advantages of agent-based simulation and discrete-event simulation to allow flexibilities in simulating evacuation scenarios. Its hybrid space of the sim...
Conference Paper
Full-text available
Agent-based simulation (ABS) has been a popular tool in various science and engineering domains. Simulating emergent behavior is one main usage of ABS. This paper investigates the use of interaction statistics as a metric for detecting emergent behaviors from ABS. An emergent behavior arises if this interaction metric deviates from normality.
Article
Full-text available
In semiconductor manufacturing, finding an efficient way for scheduling a multicluster tool is critical for productivity improvement and cost reduction. This two-part paper analyzes optimal scheduling of multicluster tools equipped with single-blade robots and constant robot moving times. In this first part of the paper, a resource-based method is...
Article
Full-text available
In this paper, we analyze optimal scheduling of a tree-like multicluster tool with single-blade robots and constant robot moving times. We present a recursive minimal cycle time algorithm to reveal a multi-unit resource cycle for multicluster tools under a given robot schedule. For a serial-cluster tool, we provide a closed-form formulation for the...
Chapter
Full-text available
Simulation modeling is an important step of a simulation study. It concerns with the creation of an efficient simulation model as accurate as needed to mimic the behavior of the underlying system and to reproduce useful observations for subsequent analysis. This introductory article discusses three main simulation modeling methods: discrete-event s...
Conference Paper
Full-text available
This tutorial demonstrates the use of agent-based simulation (ABS) in modeling emergent behaviors. We first introduce key concepts of ABS by using two simple examples: the Game of Life and the Boids models. We illustrate agent-based modeling issues and simulation of emergent behaviors by using examples in social networks, auction-type markets, emer...
Article
The effectiveness of Monte Carlo simulation for mapping materials handling cost distributions and identifying robust solutions for general block layout problems is investigated. Small scale simulations are shown to be effective at approximating materials handling cost distributions obtained from much larger scale simulations across a broad range of...
Article
Full-text available
Service enterprises are value cocreation networks. From this perspective, we analyze how hyper-network models can lead to new understanding for service science. A hyper-network is an integration of multi-layered (role-based) connections of members in a community, such as the Internet and an ecosystem. Hyper-network analysis provides new results of...
Article
Lindley's recursion is an explicit recursive equation that describes the recursive relationship between consecutive waiting times in a single-stage single-server queue. In this paper, we develop explicit recursive representations for multiserver tandem queues with blocking. We demonstrate the application of these recursive representations with simu...
Conference Paper
This paper introduces three methods to deriving gradient estimators of system performance of multi-cluster tools. A multi-cluster tool is composed of multiple single cluster tools connected non-cyclically through intermediate buffer modules. Each single cluster has a separate robot for transporting wafers within the cluster and in and out of the cl...
Article
In this paper, we define the portfolio of a generation company as the coordination of a set of generation units, which differ in production cost, capacity, and geographical location. A portfolio allows a generation company to coordinate its generators to bid strategically to earn profit more than what can be achieved without coordination. In a cons...
Article
A simple procedure is proposed to identify line layout solutions when a production facility with work centres of unequal size uses conventional material handling devices and operates under stochastic demand scenarios. The procedure uses Monte Carlo simulation (MCS) to empirically search for robust solutions defined as those that simultaneously meet...