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Changes of Resistance During Polyelectrolyte-enhanced Stirred Batch Ultrafiltration

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Journal of Donghua University(English Edition) 2007年第4期24卷 478-483页

作者：朱新生 Kwang-Ho choo Faculty of Materials Engineering Soochow University Department of Environmental Engineering Kyungpook National University Korea

The permeation flux or the resistance in the ultrafiltration process is mainly limited by osmotic pressure, and it may originate from various kinds of polymer interactions. However, the real origin of permeation resistance hasn＇t been clarified yet in the light of polymer solution nature. The removal of nitrate contamination by polyelectrolytes was carried out with stirred batch ultrafiltration. The polyelectrolyte concentrations both in permeate and retentate were analyzed with total organic carbon analyzer and permeate mass was acquired by electronic balance connected with computer. The total resistance was calculated and interpreted based on the osmotic pressures in three concentration regimes. In the dilute region, the resistance was proportional to polymer concentration; in the semidilute region, the resistance depended on polymer concentration in the parabolic relationship; in the highly concentrated solution regime, the osmotic pressure factor （OPF） would dominate the total resistance; and the deviation from OPF control could come from the electrostatic repulsion between the tightly compacted and charged polyelectrolyte particles at extremely concentrated solution regime. It was first found that dilute and semidilute concentration regions can be easily detected by plotting the leg-log curves of the polymer concentration versus the ratio of the total resistance to polymer concentration. The new concept OPF was defined and did work well at highly concentrated regime.

关键词： ultra filtration permeation resistance semi-dilute solution overlap concentration polymerchain collapse

Unusual upper gastrointestinal bleeding: Ruptured superior mesenteric artery aneurysm in rheumatoid arthritis

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World Journal of Gastroenterology 2013年第28期19卷 4630-4632页

作者： Chung-Ho choo Hsu-Heng Yen Department of Gastroenterology Changhua Christian Hospital

This case report describes an unusual case of upper gastrointestinal (UGI) bleeding caused by a ruptured superior mesenteric artery (SMA) aneurysm in the duodenum in a patient with rheumatoid arthritis. The patient presented with UGI bleeding and hemorrhagic shock. Emergency UGI endoscopy could not identify the source of the bleeding because of excessive blood clots under the second portion of the duodenum. An SMA aneurysm with active contrast extravasation was diagnosed by computed tomography. The aneurysm, together with the fourth portion of the duodenum and the proximal portion of the jejunum, was surgically resected, and the SMA was skeletonized. On postoperative day 15, the patient was discharged from hospital under satisfactory conditions. Rheumatoid arthritis has been known to cause a wide spectrum of manifestations, and an SMA aneurysm is an unusual extra-articular manifestation. An SMA aneurysm rupture presenting as upper gastrointestinal bleeding is a rare complication with a high mortality rate. The clinician must be alert to this potential issue to achieve rapid diagnostic confirmation, and immediate surgical or radiological intervention.

关键词： Gastrointestinal bleeding Aneurysm Rheumatoid arthritis Endoscopy Duodenum

Ethereum smart contract security research:survey and future research opportunities

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Frontiers of Computer Science 2021年第2期15卷 143-160页

作者： Zeli WANG Hai JIN Weiqi DAI Kim-Kwang Raymond choo Deqing ZOU National Engineering Research Center for Big Data Technology and System Services Computing Technology and System LabClusters and Grid Computing LabHubei Engineering Research Center on Big Data SecurityWuhan430074China School of Computer Science and Technology Huazhong University of Science and TechnologyWuhan430074China School of Cyber Science and Engineering Huazhong University of Science and TechnologyWuhan430074China Shenzhen Huazhong University of Science and Technology Research Institute Shenzhen518057China Department of Information Systems and Cyber Security University of Texas at San AntonioSan AntonioTX78249-0631USA

Blockchain has recently emerged as a research trend,with potential applications in a broad range of industries and *** particular successful Blockchain technology is smart contract,which is widely used in commercial settings(e.g.,high value financial transactions).This,however,has security implications due to the potential to financially benefit from a security incident(e.g.,identification and exploitation of a vulnerability in the smart contract or its implementation).Among,Ethereum is the most active and ***,in this paper,we systematically review existing research efforts on Ethereum smart contract security,published between 2015 and ***,we focus on how smart contracts can be maliciously exploited and targeted,such as security issues of contract program model,vulnerabilities in the program and safety consideration introduced by program execution *** also identify potential research opportunities and future research agenda.

关键词： smart contract security blockchain vulnerability unreliable data

Notch-δ-doped InP Gunn diodes for low-THz band applications

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Journal of Electronic Science and Technology 2023年第2期21卷 30-43页

作者： Duu Sheng Ong Siti Amiera Mohd Akhbar Kan Yeep choo Faculty of Engineering Multimedia UniversityCyberjaya63100Malaysia

The viability of the indium phosphide(InP)Gunn diode as a source for low-THz band applications is analyzed based on a notch-δ-doped structure using the Monte Carlo *** presence of theδ-doped layer could enhance the current harmonic amplitude(A0)and the fundamental operating frequency(f0)of the InP Gunn diode beyond 300 GHz as compared with the conventional notch-doped structure for a 600-nm length *** its superior electron transport properties,the notch-δ-doped InP Gunn diodes outperform the corresponding gallium arsenide(GaAs)diodes with up to 1.35 times higher in f0 and 2.4 times larger in A0 under DC *** optimized InP notch-δ-doped structure is estimated to be capable of generating 0.32-W radio-frequency(RF)power at 361 *** Monte Carlo simulations predict a reduction of 44%in RF power,when the device temperature is increased from 300 K to 500 K;however,its operating frequency lies at 280 GHz which is within the low-THz *** shows that the notch-δ-doped InP Gunn diode is a highly promising signal source for low-THz sensors,which are in a high demand in the autonomous vehicle industry.

关键词： Gunn diode δ-doped Monte Carlo Indium phosphide(InP) Terahertz source

Network traffic classification:Techniques,datasets,and challenges

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Digital Communications and Networks 2024年第3期10卷 676-692页

作者： Ahmad Azab Mahmoud Khasawneh Saed Alrabaee Kim-Kwang Raymond choo Maysa Sarsour College of Information Technology and Systems Victorian Institute of TechnologyAustralia College of Engineering Al Ain UniversityAbu DhabiUnited Arab Emirates Information Systems and Security College of ITUnited Arab Emirates UniversityAl Ain15551United Arab Emirates Department of Information Systems and Cyber Security University of Texas at San AntonioSan AntonioTX78260USA School of Photovoltaic and Renewable Energy Engineering University of New South WalesSydneyNSW2052Australia

In network traffic classification,it is important to understand the correlation between network traffic and its causal application,protocol,or service group,for example,in facilitating lawful interception,ensuring the quality of service,preventing application choke points,and facilitating malicious behavior *** this paper,we review existing network classification techniques,such as port-based identification and those based on deep packet inspection,statistical features in conjunction with machine learning,and deep learning *** also explain the implementations,advantages,and limitations associated with these *** review also extends to publicly available datasets used in the ***,we discuss existing and emerging challenges,as well as future research directions.

关键词： Network classification Machine learning Deep learning Deep packet inspection Traffic monitoring

SecBCS: a secure and privacy-preserving blockchain-based crowdsourcing system

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Science China(Information Sciences) 2020年第3期63卷 20-33页

作者： Chao LIN Debiao HE Sherali ZEADALLY Neeraj KUMAR Kim-Kwang Raymond choo Key Laboratory of Aerospace Information Security and Trusted Computing Ministry of EducationSchool of Cyber Science and Engineering Wuhan University State Key Laboratory of Cryptology College of Communication and Information University of Kentucky Department of Computer Science and Engineering Thapar University Department of Information Systems and Cyber Security and Department of Electrical and Computer Engineering University of Texas at San Antonio

A robust and scalable crowd management infrastructure is crucial in addressing operational challenges when deploying high-density sensors and actuators in a smart city. While crowdsourcing is widely used in crowd management, conventional solutions, such as Upwork and Amazon Mechanical Turk, generally depend on a trusted third-party platform. There exist several potential security concerns(e.g., sensitive leakage, single point of failure and unfair judgment) in such a centralized paradigm. Hence, a recent trend in crowdsourcing is to leverage blockchain(a decentralized ledger technology) to address some of the existing limitations. A small number of blockchain-based crowdsourcing systems(BCSs) with incentive mechanisms have been proposed in the literature, but they are generally not designed with security in mind. Thus, we study the security and privacy requirements of a secure BCS and propose a concrete solution(i.e., SecBCS)with a prototype implementation based on JUICE.

关键词： crowdsourcing blockchain secure privacy-preserving smart contract

Artificial intelligence in physiological characteristics recognition for internet of things authentication

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Digital Communications and Networks 2024年第3期10卷 740-755页

作者： Zhimin Zhang Huansheng Ning Fadi Farha Jianguo Ding Kim-Kwang Raymond choo School of Computer and Communication Engineering University of Science and Technology BeijingBeijing100083China Beijing Engineering Research Center for Cyberspace Data Analysis and Applications Beijing100083China Faculty of Informatics Engineering Aleppo UniversityAleppoSyria Department of Computer Science Blekinge Institute of Technology37179KarlskronaSweden Department of Information Systems and Cyber Security University of Texas at San AntonioSan AntonioTX78249-0631USA

Effective user authentication is key to ensuring equipment security,data privacy,and personalized services in Internet of Things(IoT)***,conventional mode-based authentication methods(e.g.,passwords and smart cards)may be vulnerable to a broad range of attacks(e.g.,eavesdropping and side-channel attacks).Hence,there have been attempts to design biometric-based authentication solutions,which rely on physiological and behavioral *** characteristics need continuous monitoring and specific environmental settings,which can be challenging to implement in ***,we can also leverage Artificial Intelligence(AI)in the extraction and classification of physiological characteristics from IoT devices processing to facilitate ***,we review the literature on the use of AI in physiological characteristics recognition pub-lished after *** use the three-layer architecture of the IoT(i.e.,sensing layer,feature layer,and algorithm layer)to guide the discussion of existing approaches and their *** also identify a number of future research opportunities,which will hopefully guide the design of next generation solutions.

关键词： Physiological characteristics recognition Artificial intelligence Internet of things Biological-driven authentication

A blockchain future for internet of things security： a position paper

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Digital Communications and Networks 2018年第3期4卷 149-160页

作者： Mandrita Banerjee Junghee Lee Kim-Kwang Raymond choo Department of Electrical and Computer Engineering University of Texas at San Antonio San Antonio TX 78249 USA Department of Information Systems and Cyber Security University of Texas at San Antonio San Antonio TX 78249 USA

Internet of Things （IoT） devices are increasingly being fotmd in civilian and military contexts, ranging from smart cities and smart grids to Internet-of-Medical-Things, Internet-of-Vehicles, Internet-of-Military-Things, Internet-of- Battlefield-Things, etc. In this paper, we survey articles presenting IoT security solutions published in English since January 2016. We make a nmnber of observations, including the lack of publicly available loT datasets that can be used by the research and practitioner communities. Given the potentially sensitive nature of IoT datasets, there is a need to develop a standard for sharing IoT datasets among the research and practitioner communities and other relevant stakeholders. Thus, we posit the potential for blockehain technology in facilitating secure sharing of IoT datasets （e.g., using blockchain to ensure the integrity of shared datasets） and securing loT systems, before presenting two conceptual blockchain-based approaches. We then conclude this paper with nine potential research questions.

关键词： Blockchain Blockchain security Collaborative security Internet-of-military things dataset self-healing security Intrusion-prevention system Predictive security Predictive security

Design of a d_(33)-mode piezocomposite electricity generating element and its application to bridge monitoring

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Journal of Central South University 2014年第7期21卷 2572-2578页

作者： Jinkyo F.choo Van Lai Pham Nam Seo Goo Department of Civil Engineering Konkuk University Department of Advanced Technology Fusion Division of Interdisciplinary StudiesKonkuk University

The piezoelectric effect is used in sensing applications such as in force and displacement ***,the brittleness and low performance of piezoceramic lead zirconate titanate(PZT) often impede its applicability in civil structures which are subjected to large *** concept of a piezocomposite electricity generating element(PCGE) has been proposed for improving the electricity generation performance and overcoming the brittleness of piezoceramic *** post-curing residual stress in the PZT layer constitutes a main reason for the PCGE's enhanced performance,and the outer epoxy-based composites protect the brittle PZT layer.A d33-mode PCGE designed for bridge monitoring application was inserted in a bridge bearing to provide a permanent and simple weigh-in-motion *** designed PCGEs were tested through a series of tests including fatigue and dynamic tests to verify their applicability for monitoring purposes in a bridge structure.A simple beam example was presented to show the applicability of the proposed bridge bearing equipped with the PCGE for adequately measuring the traffic loads.

关键词： piezocomposite electricity generating element d33-mode bridge bearing traffic monitoring