Zhenhua Li (李振华)
Associate Professor & Ph.D. Advisor, School of Software, Tsinghua University
Research Area: Mobile Cloud Computing and Future Networking
Address: East Main Building - Area 11, Office 212, Tsinghua University, Beijing, China
Email:  lizhenhua1983@gmail.com lizhenhua1983@tsinghua.edu.cn

| Representative Work | Career | Research Summary | Research Spotlights | Awards |

Representative Work in recent five years:
招收博士后(随时入站),和刘云浩老师(ACM/IEEE Fellow)联合指导,感兴趣的童鞋email联系


✈ I'm serving as PC Member of INFOCOM'20, ICC'20, WASA'20, TrustCom'20  

Our paper in MobiCom'20 -- Experience: Aging or Glitching? Why Does Android Stop Responding and What Can We Do About It? [ppt][code&dataset]

Our paper in EuroSys'20 -- Experiences of Landing Machine Learning onto Market-Scale Mobile Malware Detection [ppt][poster][code&dataset]

Our paper in FAST'20 -- Lock-Free Collaboration Support for Cloud Storage Services with Operation Inference & Transformation [ppt][code&dataset]

Two papers in INFOCOM'20 -- Automating Cloud Deployment for Deep Learning Inference [ppt] and Pinpointing Hidden IoT Devices [ppt]

Best Demo Award in MobiCom'19 -- Demo: Mobile Gaming on Personal Computers with Direct Android Emulation [video][poster]

Our paper in MobiCom'19 -- Mobile Gaming on Personal Computers with Direct Android Emulation [ppt][system with 50M users]

Three papers in MobiSys'19 -- HoneyCloud [ppt][code&dataset], Tencent OverlayChecker [ppt][dataset], and Xiaomi MVNO [ppt][system][TON'20 version]

Cover Article in中国科学:信息科学》2019年9月刊 -- 云计算应用服务开发环境:从代码逻辑到数据流图

My paper in TOMPECS'19 -- A Quantitative and Comparative Study of Network-level Efficiency for Cloud Storage Services [IMC'14 version][ppt]

Our paper in FAST'18 -- Towards Web-based Delta Synchronization for Cloud Storage Services [ppt][poster][system][source code][news report]

Our paper in VLDB'17 -- Resisting Tag Spam by Leveraging Implicit User Behaviors [ppt]

Best Student Paper Award in ACM MMSys'17 -- A Measurement Study of Oculus 360 Degree Video Streaming [ppt][source code][TOMM'18 version]

Two papers in INFOCOM'17 -- NFC-enabled AFC Attack [ppt][TMC'19 version] and CoCloud (Cross-Cloud File Collaboration) [ppt][TPDS'18 version]

My paper in NDSS'17 -- FBS-Radar: Uncovering Fake Base Stations at Scale in the Wild [ppt][presentation][system with 100M users][news report]

Cover Article & Excellent Paper Award in JTST'17 (SCI journal) -- Towards A Full-Stack DevOps Environment (PaaS) for Cloud-Hosted Applications

Two papers in INFOCOM'16 -- LightSync for Object Storage Services [ppt][TPDS'18 version] and TailCutter for Cloud CDN [ppt][TON'19 version]

My paper in NSDI'16 -- Exploring Cross-Application Cellular Traffic Optimization with Baidu TrafficGuard [ppt][system with 10M users]

Our paper in IMC'16 -- An Empirical Analysis of a Large-scale Mobile Cloud Storage Service [ppt][dataset]

My paper in IMC'15 -- Offline Downloading in China: A Comparative Study [ppt][news report]

Spotlight Paper in IEEE Transactions on Cloud Computing, 2015 -- CHARM: A Cost-efficient Multi-cloud Data Hosting Scheme ... [video]




2018.12 - now       Associate Professor & Ph.D. Advisor @ School of Software, Tsinghua University, Beijing, China
2015.11 - 2018.11 Assistant Professor & Ph.D. Advisor @ School of Software, Tsinghua University, Beijing, China
2013.7 - 2015.10   PostDoc @ School of Software, Tsinghua University, Advisor: Prof. Yunhao Liu (ACM/IEEE Fellow)
2009.6 - 2013.6     Ph.D. @ School of EECS, Peking University, Beijing, China, Advisor: Prof. Yafei Dai
2011.9 - 2012.9     Joint-Ph.D. @ University of Minnesota, Twin Cities, Advisor: Prof. Zhi-Li Zhang (IEEE Fellow)
2011.9 - 2012.9     Christianity study @ Stadium Village Church, Minneapolis, Tutor: Robert & Joanne Kraftson
2010.6 - 2010.8     Research Intern @ Tencent Research (Shanghai), Advisor: Yan Huang and Gang Liu
2008.6 - 2009.4     Software Engineer @ Marvell Technologies (Shanghai) Co. Ltd
2007.5 - 2007.10   Research Assistant @ Hong Kong Polytechnic University, Advisor: Prof. Jiannong Cao (IEEE Fellow)
2001.9 - 2008.6     Bachelor & Master @ Dept. of Computer, Nanjing University, Advisor: Prof. Guihai Chen

Research Summary:
I'm dedicated to understanding the realistic problems of today's computer systems, as well as building innovative solutions to practically address such problems. My research areas include Cloud Computing (like OpenStack), Cloud Storage (like Dropbox), Network Communication (like Offline Downloading), Mobile Computing (like Baidu PhoneGuard, Xiaomi Mobile, MIUI OS and WiFi.com), and Mobile Emulator (like Tencent Game Assistant and Tencent App Store).

Two books: (1) Content Distribution for Mobile Internet: A Cloud-based Approach, Springer statistics: 4300 downloads as of 01/2020 [Pre+ToC+Ch1];   (2) Peer-to-Peer Network: Structure, Application and Design《对等网络:结构、应用与设计》, Google scholar citations: 98, [Pre][Ch1][Ch2][Ch5][Ch9][Ref]

60+ papers on recognized conferences (NSDI, FAST*2, MobiCom*2, MobiSys*3, EuroSys, IMC*3, NDSS, VLDB, WWW, ACM-MM*3, Middleware*3, INFOCOM*7, ICDCS*2, IPDPS, ICPP*5, MMSys, PAM*2), workshops (HotStorage, NOSSDAV*2, IWQoS*2), and SCI journals (TPDS*4, TMC*4, TOMM*3, TON*2, TDSC*2, TCC*2, TOMPECS, COMNET*2, JPDC, JNCA, JCST, JTST*2).

Research Spotlights:
Why Does Android Stop Responding?

✎ Android users often experience poor responsiveness, in particular Application Not Responding (ANR) and System Not Responding (SNR) that directly disrupt user experience. We make an in-depth study of ANR/SNR at scale in the wild, uncover multifold root causes of ANR/SNR, and pinpoint the largest pathology that roots in Android's flawed implementation of Write Amplification Mitigation (WAM). We design a practical approach to eliminating this largest root cause; after large-scale deployment, it reduces almost all ANR/SNR caused by WAM.

Paper in MobiCom'20


✎ By examining apps' API invocations, we build APIChecker, an machine learning-based mobile malware detection system. The key to successfully developing such systems is manifold: 1) feature selection, 2) feature engineering, 3) app analysis speed, 4) developer engagement, and 5) model evolution. Failure in any of the above aspects would lead to "wooden barrel effect" of the entire system. APIChecker is adopted by Tencent Android App Store to efficiently check 10K newly submitted apps per day.

Paper in EuroSys'20

UFC2: User-Friendly Collaborative Cloud

✎ Mainstream cloud storage services all support collaborative file editing, which however often leads to poor experiences. We unravel a number of their design and implementation issues as the root causes. Thereby, we reconsider their collaboration support from a novel perspective of operations without using any locks. To enable this, we design intelligent approaches to the inference and transformation of users' editing operations, as well as optimizations to the maintenance of files' historic versions. We build an open-source system UFC2 to embody our design, which can avoid most conflicts with little overhead.

Paper in FAST'20

Mobile Gaming on PCs with Direct Android Emulation

✎ Efficiently emulating heavy 3D Android games on Windows PCs has long been desired while highly challenging. This paper presents DAOW, a commercial game-oriented Android emulator that implements the idea of direct Android emulation, which directly executes Android app binaries on top of x86-based Windows PCs without employing virtualization techniques. It has been widely adopted by 50M+ PC users to run thousands of heavy 3D Android games, achieving almost the same level of smoothness as being played natively on Android smartphones.

Paper and Best Demo Award in MobiCom'19


✎ Linux-based IoT devices have emerged as one primary target of today's cyber attacks. To understand realistic attacks on such devices at scale in the wild, we deploy 4 hardware IoT honeypots and 108 specially designed software IoT honeypots across eight mainstream public clouds. The measurement study leads to multi-fold insights towards actionable defense strategies that can be adopted by IoT vendors and end users.

Paper in MobiSys'19.


✎ As a key UI feature of Android, overlay enables one app to draw over other apps by creating an extra View layer on top of the host View. While greatly facilitating user interactions with multiple apps at the same time, it is often exploited by malicious apps (malware) to attack users. To combat this threat, we build OverlayChecker to automatically detect overlay-based malware at market scales. It is adopted by Tencent Android App Store to efficiently check 10K newly submitted apps per day.

Paper in MobiSys'19.

Xiaomi MVNO

✎ Mobile virtual network operators (MVNOs) operate on top of existing cellular infrastructures of base carriers, while offering cheaper or more flexible data plans. We present a two-year measurement study towards understanding various key aspects of today's MVNO ecosystem, based on Xiaomi MVNO with 1M customers. Our measurements clarify several key concerns raised by MVNO customers. We also leverage big data analytics and machine learning to optimize an MVNO's key businesses such as data plan reselling and customer churn mitigation.

Paper in MobiSys'19.

Web-based Delta Sync for Cloud Storage Services

✎ Striving towards a practical web-based delta synchronization solution for cloud storage services (e.g., Dropbox). Leveraging a series of state-of-the-art web techniques (JavaScript, WebSocket, HTML5 File APIs, and asm.js) and cloud techniques (virtual machine, object storage, and node.js), we have developed an open-source prototype solution WebR2sync+, and a usable online system THU-CloudDisk that has integrated our solution.

Paper in FAST'18.

FBS-Radar: Uncovering Fake Base Stations at Scale in the Wild


✎ Yet another key component of Baidu PhoneGuard, FBS-Radar precisely identifies malicious fake base stations (FBSes) and accurately geolocates FBSes based on crowdsourced data of nearly 100 million users. It protects users from millions of spam and fraud SMS messages per day, and has helped the Ministry of Public Security of China arrest hundreds of FBS operators. Also, we have made a public website that shows the current locations of detected FBSes in real time.

Paper in NDSS'17.

Cross-App Cellular Traffic Optimization with Baidu TrafficGuard


✎ As a key component of Baidu PhoneGuard, Baidu TrafficGuard is a third-party mobile traffic proxy widely deployed for Android 4.0+ devices in China. It effectively reduces cellular traffic using a network-layer VPN that connects a client-side proxy to a centralized traffic processing cloud. Most importantly, it works transparently across heterogeneous applications, so is not constrained to any specific app.

Paper in NSDI'16.

Offline Downloading in China: A Comparative Study


✎ Examining two typical implementations of "offline downloading" in China: the  cloud-based approach and the smart AP (access point, also known as home router) based approach. Driven by the measurement findings, we design and implement an intelligent middleware, Offline Downloading Redirector, to help users achieve the best expected performance.

Paper in IMC'15.

Towards Network-level Efficiency for Cloud Storage Services

✎ Addressing a simple yet critical question: Is the current data sync traffic of cloud storage services efficiently used?   Based on real-world traces and comprehensive experiments, we discover that a considerable portion of the data sync traffic is in a sense wasteful, and can be effectively avoided or significantly reduced via carefully designed data sync mechanisms.

Paper in IMC'14.

Efficient Batched Synchronization for Cloud Storage Services

Acting as a middleware between the user's file storage system and a cloud storage application (e.g., Dropbox), our proposed UDS (i.e., update-batched delayed sync) mechanism properly batches updates from clients to minimize the "traffic overuse problem", while preserving the rapid file synchronization that users expect from cloud storage services.

Papers in Middleware'13 and CCCF'14 (Cover Article).

Cloud Transcoder

✎ Bridging the format and resolution gap between Internet videos and mobile devices by utilizing an intermediate cloud platform. The user only sends his video request to Cloud Transcoder which does everything else: download, transcode, cache, transfer back, and so forth.

Paper in SIGMM NOSSDAV'12.

 ★ Cloud Download  (or says Offline Download)

Achieving high-quality content distribution (especially for unpopular videos) by using cloud utilities as a cache to guarantee the data health and enhance the data transfer rate. Please try the large-scale  Xuanfeng Cloud Download system!

Papers in ACM-MM'11 and JCST'15.

Cloud Tracker  (or says Open-P2SP content distribution)


✎ Dynamically tracking and integrating various third-party servers, contents and data transfer protocols all over the Internet into a large, open and federated P2SP (peer-to-server/peer) platform, so as to accelerate the content distribution from servers to clients and among peer swarms. It also facilitates load-balancing among the involved servers. Please try the large-scale  Xunlei or Xuanfeng system!

Papers in ACM-MM'11 and TPDS'13.

2019 Best Demo Award of ACM MobiCom
2019 Excellent Paper Award of Tsinghua Science and Technology(《清华学报(英文版)》优秀论文奖)
2019 Cover Article of SCIENTIA SINICA Informationis(《 中国科学:信息科学》9月刊封面文章)
2018 National Science Fund for Excellent Young Scholars国家自然科学优秀青年基金
2018 Technology Application Award from WiFi Master(WiFi万能钥匙技术应用及奖励证明)
2017 Best Student Paper Award of ACM MMSys
2017 Cover Article of JTST February Issue(《 清华学报(英文版)》2月刊封面文章)
2016 Excellence Award of CCF-Tencent Rhino-bird Open Fund(CCF-腾讯犀牛鸟基金科研优秀奖)
2015 Spotlight Paper of IEEE Transactions on Cloud Computing (Jul-Sep Issue)
2015  1st Prize of Natural Sciences, Ministry of Education(教育部自然科学奖一等奖)
2015 CAAI PhD Thesis Award(中国人工智能学会优秀博士学位论文奖)
2014 Cover Article of CCCF August Issue(《中国计算机学会通讯》8月刊封面文章)
2009 Master Thesis Award of Jiangsu Province(江苏省优秀硕士学位论文奖)
2009 1st Prize of China University Press Award(中国大学出版社图书奖一等奖 )
2009, 2010, 2011, 2012 1st, 2nd, 3rd & 4th President's PhD Scholarships of Peking University(北京大学第1/2/3/4届博士生校长奖学金¥36000*3.5
2011-2012 Scholarship for Studying Overseas from China Scholarship Council(国家公派留学奖学金$1600*12
2012 Academic Innovation Award of Peking University(北京大学“学术创新奖”)
2012 Ten Academic Elites of EECS, Peking University(北京大学信息学院“学术十杰”)
2009 Outstanding Master's Degree Thesis of Jiangsu Province, 2009(江苏省2009年度优秀硕士学位论文奖)
2008, 2010 Tung OOCL Scholarship(董氏东方奖学金 )¥5000*2
2008 HP Excellent Student Scholarship(惠普奖学金)¥5000
2007 Nanrui Company Scholarship(南瑞继保奖学金 )¥4000
2003, 2004 National Scholarship for Chinese Undergraduates(本科生国家奖学金 )¥8600 + 10600
2002, 2004 People's Scholarship of Nanjing University(南京大学人民奖学金 )¥1500 + 2500
2003 National English Contest of College Students, the second prize(全国大学生英语竞赛二等奖)

桃花庵歌 (明)唐寅

桃花坞里桃花庵,桃花庵下桃花仙。  桃花仙人种桃树,又摘桃花卖酒钱。

酒醒只在花前坐,酒醉还来花下眠。  半醒半醉日复日,花落花开年复年。

但愿老死花酒间,不愿鞠躬车马前。  车尘马足富者趣,酒盏花枝贫者缘。

若将富贵比贫贱,一在平地一在天。  若将贫贱比车马,他得驱驰我得闲。

世人笑我太疯癫,我笑他人看不穿。  不见五陵豪杰墓,无花无酒锄作田。


by 洛兵

晚钟敲响从城市那边  飞来宁静的翅膀
有家的人请回你们的家  没家的人请走进那夕阳

晚钟敲响从夕阳的眼中  流出宁静的凄凉
爱我的人请过来一起唱  恨我的人请躲开那月光

晚钟敲响从新月的梦里  落下宁静的忧伤
生者依旧习惯地擦去泪水  逝者已矣请返回你们的天堂

晚钟敲响从天堂上面  传来星空的回荡
醒来的人请守好你们的梦想  沉睡的人请把一切遗忘