Blockchain for Construction in the Post-COVID-19 Era
Fan Xue

Dept. of Real Estate and Construction, University of Hong Kong

7 November 2020, Taiyuan, China

Outline
1

原理 Principles

2

案例 Cases

3

机遇 Opportunities

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

0.1 港大 iLab 实验室
 HKU iLab 城市大数据实验室: The urban big data hub
 Director: Prof. Wilson Lu 主任：吕伟生教授
 Urban big data hub at Faculty of Architecture, HKU 港大建筑学院

iLabHKU

 multi-dimensional and multi-disciplinary urban big data collection,

storage, analysis, and presentation to inform decision-making in
urban development

fac.arch.hku.hk/iLab

 Focusing on information technology (IT)
o Building Information Modeling (BIM)

o Geographical Information System (GIS)

o Global Navigation Satellite System (GNSS)
o Urban Remote Sensing (URS)
o Internet of Things (IoT)
o Blockchain (BC/DLT)

2020 New Year dinner

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

0.2 About myself 自我介绍
 A mixed background 背景
 BEng in Automation, CAUC
 MSc in Computer Science, CAUC
 PhD in System Engineering, HKPU

 Engineering 工程
2004

 ISE, CEM, EIE

2007

 Computer Science 计算机

2012

 AI, OR, ML, SE, DBA

 PDF/RAP/AP in Construction IT

 Research interests 方向

 Economics 经济
 SCM

 Automation/IT in construction 智慧建造
 Urban sensing and computing 城市计算
 Applied operations research, ML, etc. 优化算法

 Professional 专业协会
 MACM, SMCGS, MIEEE, MHKGISA
 Sec. ACM-HK, CM. CGS-BIM (appl.)

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, Homepage
11 Novemberfor
2020,
Taiyuan,
China
new
updates
(free full-texts)

0.2 My research projects 主持项目（约500万港币）
 On-going 在研

 Keywords 关键词

 PI: HK RGC GRF/ECS (17201717, 17200218, 27200520), HKU (102009917, 201910159238)  BIM/ CIM/ DTB/ DTC
 Co-PI: ITF (ITP/029/20LP), Key R&D Guangdong (2019B010151001), HKU PTF
(102009741)

 Co-I: NSFC General (71671156), NSSFC Key (17ZDA062), HK SPPR
(S2018.A8.010.18S), HK ECF (111/2019)

 Completed 完成
 PI: HKU (201702159013, 201711159016, 201811159177), HKU-Tsinghua SPF (20300083),

o 数字孪生城市

 3D point cloud 三维点云
 Derivative-free

optimization (DFO)
 Construction blockchain

 Co-I: NSFC General (60472123), HK PPR (2018.A8.078.18D)

 Job vacancy (1 PhD + 10 RAs openings) 职位空缺
 RA/PhD (Web BIM, LoWaWAN/Nb-IoT hardware, Blockchain, software

engineering), transferable to PhD (vision, rigor, & performance)
 HK$200,000~400,000/year

Sponsors of projects as PI/Co-PI

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

Section 1

原理

PRINCIPLES

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

1 What is a blockchain? 定义、三要件
 Blockchain 区块链
 Linked-list-like incremental Block

data storage systems

o Saved distributed, identically on each “node”
o Verified by “miners” for rejecting Bad

o Each “solved” Block becomes immutable

 Less related to

Bitcoin 比特币,

Ethereum 以太坊, DApp

 Maturity level
o Blockchain 1.0; 2.0; 3.0; 4.0 (?) …

time

新瓶旧酒？鸡尾酒?

 Three old components “wine” in any blockchain “bottle”
Sects. 1.1, 2.1  Distributed storage (1970s) 分布式存储
Sect. 1.2

 Consensus mechanisms (1990s) 共识

Sects. 2.2, 2.3  Cryptographic tools (1990s) / smart contract (1990s) 加密/合约

Root
#n
#2
Node #1

Diagram of a blockchain
Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan,
China
(miners
hidden)

Block
Bad

1.1 Distributed storage (1970s) 【1】分布式存储
 In database management system (DBMS) domain,
the 1970s contributed
 New hardware
o Hard disk computer 机械硬盘

o Solid State Disk (SSD) 1970 固态硬盘

 New software

o Relational DBMS

o E.g., SQL/DS, SEQUEL, DB2

o Distributed data storage 分布式存储理论
o
o

Rosenkrantz et al. (1978)
Hevner and Yao (1979)

IBM System/38 (1978), specified database computer
(Source: Wikipedia.org, Author: CarstenSchulz)

 New data system:

o Data warehouse

Relational
dataTaiyuan,
tables (Source:
Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November
2020,
China Author)

1.2 PoW consensus 【2】工作量证明共识
 Invented against Email spam (junk email)
 Appeared in early 1990s
 90+% world emails were spam by 2014
 Reason 1: Spamming cost ~ 0;
 Reason 2: Assuming-people-are-good Email protocols

 Dwork & Naor (1992): ‘Proof of computational efforts’
计算量证明

 “If I don’t know you and you want to send me a message, then

you must prove that you spent, say, ten seconds of CPU time,
just for me and just for this message.” (Dwork et al. 2003)

 Jakobsson & Juels (1999): ‘Proof of work’
工作量证明

 Where a prover demonstrates to a verifier that he has expended a

certain level of computational effort in a specific time interval
Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

1.2 PoW consensus: On hard-to-solve, easy-tocheck math problems ——NPC问题
 Sudoku puzzle 数独
 Each column, each row, and each of the nine 3×3 grids
o All nine digits (1-9)

 Hard to solve, easy to check
 Nondeterministic Polynomial time-Complete (NPC) when n > 3

 And Max clique, Boolean satisfiability, Subset sum, …
 NPC （数学/计算复杂度领域：NP完全问题）

 And, e.g., hashcash PoW (Back 1997; 2002) 早期的“工作量证明”文献
 PUBLIC: H(), k
o k: difficulty

 MINT: solving = O(2k) complexity
 VALUE: checking = O(k) complexity

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

1.2 PoW consensus: How it works
 Proof of work (PoW) 工作量证明
 A class of consensus
 Sender / prover / miner side
o Hard to solve (e.g., Soduko, hashing, …)

 Server / verifier / node side
o Easy to check

 Examples 例子（红框的例子，可在中标麒麟Linux上测试）
1.

Hashcash PoW (Back 1997; 2002)
o X-Hashcash: 1:52:380119:calvin@comics.net:::9B760005E92F0DAE

o $ echo -n 1:52:380119:calvin@comics.net:::9B760005E92F0DAE | openssl sha1

$ 0000000000000756af69e2ffbdb930261873cd71 ( correct; 13 hex (52 binary) 0s in <1us)

2.

Email attaches a key to the Sudoku’s initialized by sender + content + Email time

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

1.3 Nakamoto (2008)’s Bitcoin 【3】BTC数据加密
 Bitcoin = BC 1.0 app 比特币=区块链1.0应用
 Immutable 不可篡改
 1 block = many transactions
 1 trans = 1 sender + 1 receiver + amount

 Anonymous 匿名
 Hash “wallets”

区块 （平均10分钟一个，难度k调节）
1. 类“数独”的解

2. 链接到前一个块

 Secure (and expensive) 可靠（浪费）
 ~ 125EH/s (1.2 ×1020 H/s) computational power

3. Merkel树型
数据存储
汇款人

收款人

BTC

 ~100TWh/year
o 2× Google, 4× Ireland, or US$10B bill

 Decentralized (pseudo?) （伪）分布式
But, > 65% in China, > 35% in Xinjiang (Gogo 2020)


Xue, F. (2020). Blockchain
for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

4. （全世界所有）比特币支付记录

1.3 Bitcoin’s consensus: 为啥“挖矿”能挣“钱”？
 A “miner” is a prover 矿工：证明账单纪录

1. 放出新块（缺下图红框nonce）

 Solves the hashcash PoW
o Data content = trans + hash pointer
o Return ‘nonce’ to server

2. 矿工解题“挖矿”

3. 验算答案

 Receives reward as BTC

 Server / node validator 服务器/客户验证

4. 给第一个正确矿工发一点币

 Collects and packs transactions
 Opens a puzzle for millions of machines
o Flexible difficulty: every 10 mins per block

 Awards the winner with 6.25 BTC (now)

 The ledger (> 200 GB now) 总账单

 Live on millions of devices (Space redundant)
Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

1.3 PoW’s cons: 51% attack and more 并非100%安全
 A malicious miner 恶意矿工
 Tries to modify transactions
o E.g., change his/her -100 BTC to 0
o (by US$1M goods for free)

 Can succeed if > 50% computing power

 Other cons 其他问题

 Competitiveness between miners
o Root cause of 51% attack
o Too much energy cost

 21 million hard cap BTC
 Easy coins before 2010

o 97% bitcoins were held by 4% of addresses

ofPost-COVID-19
those unregistered
Xue, F. (2020). BlockchainoforRegardless
Construction in the
Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

1.4 Blockchain take-away 小结
 Blockchain = a (distributed, encrypted, trustworthy) database 区块链 = 数据库
 Some characteristics meet smart construction requirements
 Immutability
 Distributedness
 Transparency
 Security

要点： (1) 区块链不是“加密币”(2)“加密币”不是货币

 Blockchain is not equal to “crypto-currency” (not currency)
 Good medium of exchange  便于交易
 Poor store of value  价值储蓄
o See the right picture

 Inappropriate unit of account  信用的度量单位
o Countless new ‘coins’ (> 5,000 now)

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 NovemberBitcoin
2020, Taiyuan,
price China

Section 2

案例

CASES

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.1 Case 1 案例1: Procurement 采购 (Yang et al. 2020)
 Construction procurement 采购
 Multiple parties, distributed
 Having possible trust/compliance problems
 Involving payment, quality assurance

 Yang et al.’s (2020) example
 Purchasing a distillation tower 买蒸馏塔
 In five steps 五个步骤

 Objective 目的
 Blockchaining the procurement
o E.g., “pay AU$ 30,100”

 On Ethereum (Blockchain 2.0) as a 1.0 way
Processing of purchasing construction equipment
(Reprinted with permission)

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.1 【1】Data storage 存储: From 2 to >1 million
 Model mapping as a smart contact 流程建模
 Modeled in “App server”
 A “World state” computer in a Ethereum “virtual machine”

 Data in the application layer (top left) 数据
 Two parties
 6 world states, 5 steps

 On chain 链上

Two parties

Data saved by >1M users,
each user has one copy;

 > 1M user (data copies)
 ~ 30,000 similar smart

contracts per day

Buried in ~30,000 smart
contracts/day
Ethereum-based architecture
(Reprinted with permission)

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.1 ETH transactions 以太坊的交易建模
 Each step is transformed
 To a ETH transactions

 ETH’s Transaction fee
 ~HK$0.1 / step
 ~HK$0.5 for each procurement

 Note:
 Payment was offline

Procurement (Steps 4, 5) was transformed into Ethereum transactions
with
Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference(Reprinted
- Youth Forum,
11 permission)
November 2020, Taiyuan, China

3.2 Case 2 案例2 : Supply Chain 供应链 (Lu et al. 2020)
 Cross-border construction supply chain 大湾区建筑业供应链
 Trackability and traceability 可追踪性、可追查性
 IoT 物联网
 GPS/北斗等定位信号

 Problems 问题
 Unstable communication
 Possible false signals

 Lu et al.’s (2020) blockchain solution
 smart construction objects (SCOs) enabled blockchain oracles (SCOs-BOs)
 Smart contracts 四类智能合约
o Service, aggregator, oracle, and reputation

(物联网驱动的全自动区块链)

Source: (Lu et al. 2020)

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.2 Smart contracts 智能合约组合（主链+分链）
 Two on main chain 主链有2个智能合约
 Service 服务
o Data inquiry

 Aggregator 共识整合
o >51% SCOs for consensus

 Two on side chains 分链有2个智能合约
 Oracle 沟通者

o Unbiased randomization 无偏随机化

 Reputation 声望

o Accumulated reputation over time 时序声望积累

 Results: Two-chain secure of IoT locations consensus
 Note: (Lu et al. 2020) is under review, citable

Source: (Lu et al. 2020)

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.3 Case 3 案例3: BIM changes BIM变更 (Xue & Lu, 2020)
 Rome wasn’t built in a day; so wasn’t BIM. “BIM不是一天画成的”

Xue & Lu (2020):
如果有个500M的BIM，每分钟的改
动的实质信息量不足文件的0.01%。
所以，没有必要每次交换整个BIM文
件；可以分离出改动量用区块链同步。
(BIM数据/语义复用问题)

(a) Incremental
in geometry,
+ non-geometric
semantics
(Ellis
2019)
Xue, F. (2020). Blockchain for Construction
in the Post-COVID-19
Era. (b)
The in
6thgeometric
China BIM Conference
- Youth Forum,
11 November
2020,
Taiyuan, China

3.3 Semantic differential transaction 语义差分记录
 IFC (Industry Foundation Classes)
 The best open BIM standard
 STEP (Standard for the Exchange of Product Data) format

Example IFC

ISO-10303-21;
HEADER;
FILE_DESCRIPTION(('ViewDefinition [CoordinationView, …);
FILE_NAME('example.ifc','2008-08-01T21:53:56',('Architect…);
FILE_SCHEMA(('IFC2X3'));
ENDSEC;
DATA;
#1=IFCOWNERHISTORY(#84,#71,$,.ADDED.,$,$,$,1217620436);
#2=IFCAXIS2PLACEMENT3D(#11,#4,#8);
#3=IFCCARTESIANPOINT((0.0,0.0));
#4=IFCDIRECTION((0.0,0.0,1.0));
#5=IFCGEOMETRICREPRESENTATIONCONTEXT($,'Model',3,1.0E-5,#75,$);
#6=IFCWALLSTANDARDCASE('3vB2YO$MX4xv5uCqZZG05x',#1,'Wall …);
#7=IFCWINDOW('0LV8Pid0X3IA3jJLVDPidY',#1,'Window xyz’,’…);
#8=IFCDIRECTION((1.0,0.0,0.0));
#9=IFCOPENINGELEMENT('2LcE70iQb51PEZynawyvuT',#1,'Opening …);
#10=IFCCARTESIANPOINT((0.75,0.0));
# 11 =IFCCARTESIANPOINT((0.0,0.0,0.0));
#12=IFCCARTESIANPOINT((0.0,0.3));
#13=IFCORGANIZATION($,'TNO','TNO Building Innovation',$,$);
#14=IFCPROPERTYSINGLEVALUE('AcousticRating','AcousticRating’,…);
#15=IFCPROPERTYSINGLEVALUE('Reference','Reference',IFCTEXT(''),$);
#16=IFCPROPERTYSINGLEVALUE('FireRating','FireRating',IFCTEXT(''),$);
#17=IFCPROPERTYSINGLEVALUE('IsExternal','IsExternal',IFCBOOLEAN(.T.),$);
#18=IFCPROPERTYSINGLEVALUE('ThermalTransmittance’,…);
#19=IFCQUANTITYLENGTH('Height','Height',$,1.4);
#20=IFCQUANTITYLENGTH('Width','Width',$,0.75);
#21=IFCLOCALPLACEMENT($,#2);
#22=IFCBUILDING('0yf_M5JZv9QQXly4dq_zvI',#1,'Sample Building’,…);
#23=IFCBUILDINGSTOREY('0C87kaqBXF$xpGmTZ7zxN$',#1,…);
#24=IFCLOCALPLACEMENT(#21,#2);
…
END-ISO-10303-21;
Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November
2020, Taiyuan, China

 Clear, [hardly] readable

 But massive, involving many random global IDs

 Our in-house program for the SDTs. 语义差分记录

主要任务1: 清除随机ID 干扰
主要任务2：计算最小变化量

(Xue & Lu 2020)

3.3 SDT tests 举例
 Changing a window’s size

操作：窗口变宽一点

Input
IFC
(7.4KB
each)

Item
Size (KB)
Time (s)
SH?*
Output

Line-by-line file comparison
1.00
0.041

6 changed lines:

The proposed SDT
0.36
0.003

4 changed properties:

IFCXML
(32.9KB
each)

Size (KB)
Time (s)
SH?*
Output

0.56
0.042

6 changed lines:

0.89
1. 墙面改变
0.012
2. 空缺改变

6 changed properties: 3. 窗组件改变

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China
BIMsemantic
Conference
- Youth Forum, 11 November 2020, Taiyuan, China
*: With
hierarchies?

IFC改变：

3.2 BIM change contract 变更合约
 BIM change contract (BCC)变更合约
 BCCt: All BIM changes at time t
o BCCi = ⊕n σi

o Note: ⊕ is the simplest operation for proof-of-

concept

 A BIM can be created from the model at t - 1 and

changes at t

o ifct = ifct-1 + BCCt.

 BIM at any time can be recovered from base BIM

and the chained BCCs
o ifct = ifc0 + Σt BCCi.

 Data storage 数据存储
 Permissioned nodes (stakeholders), not public

Permissioned blockchain architecture
(Reprinted with permission)

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.3 Another test case 大一点的例子 (Xue & Lu, 2020)
 Autodesk Revit 2018’s sample BIM (a modern villa, 27.4 MB in IFC)
 Sequential / simultaneous roof window changes
 By two BIM users, from t = 0 to 4
 t2 → t3: Simultaneous changes by two users

A test case
Xue, F. (2020). Blockchain for Construction in the Post-COVID-19
Era. The 6th
China
BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China
(Reprinted
with
permission)

3.3 SDT/BCC results 测试结果
 t2 → t3 前一页的红圈步骤
 User A: Added a roof window
o σA = top left block

 User B: Added text comments to

another window

o σB = bottom left block

 BCC as the conflict-free merge
 BCC = right block

 BCC is efficient (<0.02%)

Combining SDTs to BCC at t2 → t3
(Reprinted with permission)

Line-by-line file comparison
The proposed BCC/SDT
Size (KB) Time
Size
Interop.
SDT
SH?#
(lines)
(s)*
(KB)
time (s)*
time (s)*

IFC
t2→ t3
54,700
0.789

(27.4MB
(Arch.) (533,923)
3.45
6.681
0.463


each)
t2→ t3
53,900
0.756
(Client) (514,192)
Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

 3.37KB out of 27.4MB IFC

Input

Change

SH?#

0.79s

Good for blockchaining



3.3 SDT/BCC application 1 应用场景1
 Fraud detection 欺诈检测
 On a simplest blockchain
 Web-based
 Easy nonce
 Visualized blocks
o Green = verified; red = wrong / hacked

 BIM was immutable from

 claiming false authorships,
 destroying evidence, or
 being hacked, etc.

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

Section 3

机遇

OPPORTUNITIES

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.1 Smart construction 智慧建造
 Construction is known as a “backward industry”
 Low productivity, labor-intensive (v.s. aging workers)
 Fatality, occupational hazards, management (e.g., cost overrun)

 A consensus of global research institutes (e.g., Harty et al., 2007)
 Effective (productive, automatic, age friendly) and efficient

(safer, profitable, on-time, sustainable) industry

 Construction smartization with new Information Tech.
 Computing power
 New data, e.g., RFID, LiDAR, GPS, UAV, smart phones, …
 New technologies, e.g., BIM, GIS, CV, VR/AR, blockchain, …

USA’s gross value-added by sectors
source: economist.com

 13部委:《关于推动智能建造与建筑工业化协同发展的指导意见》(建市〔2020〕60号)
 9部委:《关于加快新型建筑工业化发展的若干意见》（建标规〔2020〕8号）

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.1 The COVID-19 outbreak 新冠冲击
 COVID-19 impacted and perhaps will change for ever
新冠影响了，并可能永久改变
 Construction collaboration
 Construction procurement
 Construction supply chain
 BIM-based project collaboration
 Etc.

概率密度

 The silver lining 乐观方面
 Promoting new technologies (Agarwal et al. 2020)
o Cloud meeting (face-to-face)

o Remote working (office teamwork)

o Distributed collaboration (traditional)

Rogers’s (1962) diffusion of innovations model

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.2 A new distributed norm ? BC=分布式新范式？
 Multi-stage construction life cycle
 Architectural design
 Engineering design
 Construction
 Operation & maintenance
 Demolition

 Many stakeholders
 Even more decision makers, professionals
 Teaming  Coordination Collaboration

挑战

 Challenges ahead of blockchain collaboration?
 Spatially and Temporally
 Semi-controlled working environment

Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.3 Discussion
 Existing blockchain applications for smart construction
 Works, e.g., blockchaining SCM and BIM changes
 but preliminary and infantile

 The characteristics of blockchain are appropriate for
construction
 Immutability, transparency, security (e.g., no data loss)

 Challenges ahead
 Culture, regulation, governance
 Cost and efficiency (e.g., not widely used to fight spams)
 Security (e.g., business secrets, privacy)
o Channel

透明度问题

加密数据频道

 Understanding and acceptance
Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

3.4 Recruitment for a new project
 [World first] “BIM Square”: Blockchain and i-Core-enabled Multi-stakeholder
Building Information Modelling Platform for Construction Logistics and
Supply Chain Management in Hong Kong. HKITC ITF ($10.36 million)
 基于区块链、建筑信息模型及物联网的面向香港建造业多持份者的物流及供应
链管理平台研发（暂译） 【1036万港币，全球第一个同类科研】
 1 RA/PhD: LoRaWAN / Nb-IoT 硬件、通讯、Oracle分链共识和协议
 3 RA/PhD: 3D模块装配式建筑：1物流、2品控、3工地DT调度
 1 RA/PhD: 面向建筑行业的区块链(3.0, 4.0)理论、架构、实现
 1 RA/PhD: 联邦主链云服务、Web BIM、手机App、插件等
 1 RA/PhD: IFC语义研究、Open BIM理论和算法
 欢迎传播，意向请联系：李骁博士 < 电邮 xli1991@hku.hk >
恰饭时间
Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

References
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Xue, F. (2020). Blockchain for Construction in the Post-COVID-19 Era. The 6th China BIM Conference - Youth Forum, 11 November 2020, Taiyuan, China

If you want to go fast, go alone.
If you want to go far, go together.
— African proverb非洲谚语

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