Internet of Things

Article	Citations
Attack and anomaly detection in IoT sensors in IoT sites using machine learning approaches	385
Predicting the growth and trend of COVID-19 pandemic using machine learning and cloud computing	273
Internet of Things (IoT) and Agricultural Unmanned Aerial Vehicles (UAVs) in smart farming: A comprehensive review	246
Security analysis of drones systems: Attacks, limitations, and recommendations	229
Transformative effects of IoT, Blockchain and Artificial Intelligence on cloud computing: Evolution, vision, trends and open challenges	208
Blockchain technology: A survey on applications and security privacy Challenges	202
Survey on IoT security: Challenges and solution using machine learning, artificial intelligence and blockchain technology	188
Blockchain for the IoT and industrial IoT: A review	177
AI for next generation computing: Emerging trends and future directions	138
A survey on internet of things security: Requirements, challenges, and solutions	132
Internet of Things research in supply chain management and logistics: A bibliometric analysis	102
Performance evaluation metrics for cloud, fog and edge computing: A review, taxonomy, benchmarks and standards for future research	92
IoMT-SAF: Internet of Medical Things Security Assessment Framework	90
Machine learning approaches to IoT security: A systematic literature review	90
Security aspects of Internet of Things aided smart grids: A bibliometric survey	86
The Internet of Things for enterprises: An ecosystem, architecture, and IoT service business model	81
The fog cloud of things: A survey on concepts, architecture, standards, tools, and applications	81
Smart farming: Agriculture's shift from a labor intensive to technology native industry	79
A smart farming concept based on smart embedded electronics, internet of things and wireless sensor network	76
Healthcare and patient monitoring using IoT	67
TinyML Meets IoT: A Comprehensive Survey	64
Secure IoT communications for smart healthcare monitoring system	60
A survey on consensus methods in blockchain for resource-constrained IoT networks	58
SecOFF-FCIoT: Machine learning based secure offloading in Fog-Cloud of things for smart city applications	58
Future Smart Connected Communities to Fight COVID-19 Outbreak	55

Blockchain leveraged decentralized IoT eHealth framework	55
LoRaWAN security survey: Issues, threats and possible mitigation techniques	53
Identification and Authentication in Healthcare Internet-of-Things Using Integrated Fog Computing Based Blockchain Model	52
A Methodological Approach for Predicting COVID-19 Epidemic Using EEMD-ANN Hybrid Model	52
Semantic Web Technologies for the Internet of Things: Systematic Literature Review	52
IoT based real time energy monitoring system using Raspberry Pi	48
Secure remote anonymous user authentication scheme for smart home environment	47
A survey on machine learning in Internet of Things: Algorithms, strategies, and applications	47
A survey on the architecture, application, and security of software defined networking: Challenges and open issues	47
A survey on Assistive Technology for visually impaired	47
Cryptographic technologies and protocol standards for Internet of Things	46
A survey of IoT protocols and their security issues through the lens of a generic IoT stack	46
An IoT patient monitoring based on fog computing and data mining: Cardiac arrhythmia usecase	46
Toward the automation of threat modeling and risk assessment in IoT systems	45
A smart IoT based system for monitoring and controlling the sub-station equipment	45
An IoT based device-type invariant fall detection system	44
Internet of things-based fog and cloud computing technology for smart traffic monitoring	43
Dew Computing Architecture for Cyber-Physical Systems and IoT	43
IoT-based enterprise resource planning: Challenges, open issues, applications, architecture, and future research directions	42
Identifying the attack surface for IoT network	40
Smart garbage management system for a sustainable urban life: An IoT based application	40
Energy-Efficient IoT-Health Monitoring System using Approximate Computing	39
CyberLearning: Effectiveness analysis of machine learning security modeling to detect cyber-anomalies and multi-attacks	39
Novel trust consensus protocol and blockchain-based trust evaluation system for M2M application services	39
Harnessing the power of Internet of Things based connectivity to improve healthcare	39
Humanitarian Drones: A Review and Research Agenda	38
Deep learning assisted COVID-19 detection using full CT-scans	37
A comprehensive survey of prominent cryptographic aspects for securing communication in post-quantum IoT networks	37
FogIoHT: A weighted majority game theory based energy-efficient delay-sensitive fog network for internet of health things	37
Deep Belief Network enhanced intrusion detection system to prevent security breach in the Internet of Things	37
Analysis of internet of things malware using image texture features and machine learning techniques	36
Perspectives on emerging directions in using IoT devices in blockchain applications	36
Internet of Things Forensics: A Review	35
Integrating the Internet of Things in the halal food supply chain: A systematic literature review and research agenda	35
IoT supported smart home for the elderly	33
PUF-derived IoT identities in a zero-knowledge protocol for blockchain	33
FANETs in Agriculture - A routing protocol survey	33
The Challenges of IoT Addressing Security, Ethics, Privacy, and Laws	32
Genetic Algorithm based Internet of Precision Agricultural Things (IopaT) for Agriculture 4.0	32
Highly-efficient fog-based deep learning AAL fall detection system	31
An IoT-enabled intelligent automobile system for smart cities	30
Coordination and management of cloud, fog and edge resources in SDN-VANETs using fuzzy logic: A comparison study for two fuzzy-based systems	30
A conceptual IoT-based early-warning architecture for remote monitoring of COVID-19 patients in wards and at home	29
A mapping of IoT user-centric privacy preserving approaches to the GDPR	29
IoT-Cognizant cloud-assisted energy efficient embedded system for indoor intelligent lighting, air quality monitoring, and ventilation	28
The big picture on the internet of things and the smart city: a review of what we know and what we need to know	28
Positioning of blockchain mechanisms in IOT-powered smart home systems: A gateway-based approach	27
DeL-IoT: A deep ensemble learning approach to uncover anomalies in IoT	27
Federated learning with hyperparameter-based clustering for electrical load forecasting	27
AppsPred: Predicting context-aware smartphone apps using random forest learning	26

An IoT based Congestion Control Algorithm	26
A ZigBee Intrusion Detection System for IoT using Secure and Efficient Data Collection	26
Intrusion detection based on Machine Learning techniques in computer networks	26
A Systematic Review of Organizational Factors Impacting Cloud-based Technology Adoption Using Technology-Organization-Environment Framework	26
An Efficient Mutual Authentication Scheme for Internet of Things	26
Lightweight privacy-preserving power injection and communication over vehicular networks and 5G smart grid slice with provable security	25
HealthCloud: A system for monitoring health status of heart patients using machine learning and cloud computing	25
Practical fall detection based on IoT technologies: A survey	25
Agri-Info: Cloud Based Autonomic System for Delivering Agriculture as a Service	25
Multi-label classification based ensemble learning for human activity recognition in smart home	24
A trust management system for fog computing services	24
Smart City Data Science: Towards data-driven smart cities with open research issues	24
Designing a SHA-256 processor for blockchain-based IoT applications	23
The architectural design of smart blind assistant using IoT with deep learning paradigm	23
A service oriented IoT architecture for disaster preparedness and forecasting system	23
Benchmarking RSS-based localization algorithms with LoRaWAN	22
An effective approach of latency-aware fog smart gateways deployment for IoT services	22
Threat model for securing internet of things (IoT) network at device-level	21
A novel medical image fusion method based on Rolling Guidance Filtering	21
Ensemble Detection Model for IoT IDS	21
LoRa+: An extension of LoRaWAN protocol to reduce infrastructure costs by improving the Quality of Service	21
Cyber resilience in firms, organizations and societies	21
An IoT General-Purpose Sensor Board for Enabling Remote Aquatic Environmental Monitoring	21
Smart mask – Wearable IoT solution for improved protection and personal health	21
IoT anomaly detection methods and applications: A survey	20
An IoT Raspberry Pi-based parking management system for smart campus	20
Evaluating Internet of Medical Things (IoMT)-Based Systems from a Human-Centric Perspective	20
A Blockchain System with Lightweight Full Node Based on Dew Computing	20
Smart energy optimization for massive IoT using artificial intelligence	20
Cost-sensitive stacked auto-encoders for intrusion detection in the Internet of Things	20
Secure and lightweight communication in heterogeneous IoT environments	19
Smart vehicular traffic management: An edge cloud centric IoT based framework	19
A Tabu list strategy based DQN for AAV mobility in indoor single-path environment: Implementation and performance evaluation	19
Ethereum smart contracts: Analysis and statistics of their source code and opcodes	19
TDAoA: A combination of TDoA and AoA localization with LoRaWAN	18
A security monitoring system for internet of things	18
WoT Store: Managing resources and applications on the web of things	18
LoRaWAN-Based IoT System Implementation for Long-Range Outdoor Air Quality Monitoring	18
Data management and internet of things : A methodological review in smart farming	18
Discovering location based services: A unified approach for heterogeneous indoor localization systems	18
EEG signal analysis for epileptic seizures detection by applying Data Mining techniques	18
Development of an Internet of Things solution to monitor and analyse indoor air quality	18
Support vector machine and YOLO for a mobile food grading system	17
Capacity of blockchain based Internet-of-Things: Testbed and analysis	17
A survey on security in internet of things with a focus on the impact of emerging technologies	17
The Internet of Things (IoT) in healthcare: Taking stock and moving forward	17
Internet of smart-cameras for traffic lights optimization in smart cities	17
Scalable and Robust Outlier Detector using Hierarchical Clustering and Long Short-Term Memory (LSTM) Neural Network for the Internet of Things	17
Tradable mobility permit with Bitcoin and Ethereum – A Blockchain application in transportation	16
A Survey of Indoor Location Technologies, Techniques and Applications in Industry	16
The Interplay between the Internet of Things and agriculture: A bibliometric analysis and research agenda	16
Characterizing Internet of Things Systems through Taxonomies: A Systematic Mapping Study	16
Energy efficient mechanism for LoRa networks	16
Designing and constructing internet-of-Things systems: An overview of the ecosystem	15
Predicting parking occupancy via machine learning in the web of things	15
Intelligent authentication of 5G healthcare devices: A survey	15
A dynamic access-point transmission power minimization method using PI feedback control in elastic WLAN system for IoT applications	15
Monitoring of water quality in a shrimp farm using a FANET	15
What are IoT systems for real? An experts’ survey on software engineering aspects	15
Trajectory pattern extraction and anomaly detection for maritime vessels	15
Anonymous mutual IoT interdevice authentication and key agreement scheme based on the ZigBee technique	15
Resource discovery techniques in the internet of things: A review	14
The applications of Internet of Things in the automotive industry: A review of the batteries, fuel cells, and engines	14
Factors influencing adoption model of continuous glucose monitoring devices for internet of things healthcare	14
Joint slice-based spreading factor and transmission power optimization in LoRa smart city networks	14
Requirements for distributed task placement in the fog	14
The Redundant Energy Consumption Laxity Based Algorithm to Perform Computation Processes for IoT Services	14
A survey of blockchain-based IoT eHealthcare: Applications, research issues, and challenges	14
Advancements in distributed ledger technology for Internet of Things	14
Energy-efficient modified DCC-MAC protocol for IoT in e-health applications	14
A scalable and distributed architecture for secure and privacy-preserving authentication and message dissemination in VANETs	14
What Do Practitioners Discuss about IoT and Industry 4.0 Related Technologies? Characterization and Identification of IoT and Industry 4.0 Categories in Stack Overflow Discussions	14
Data analysis and mining of the correlations between meteorological conditions and air quality: A case study in Beijing	14
Scalable and secure product serialization for multi-party perishable good supply chains using blockchain	14
On the performance of distributed ledgers for Internet of Things	14
A randomised control trial for measuring student engagement through the Internet of Things and serious games	14
Energy efficient resource optimization in cooperative Internet of Things networks	13
Analysis of IoT mechanisms for media streaming	13
Location prediction using GPS trackers: Can machine learning help locate the missing people with dementia?	13
Information Flow Control Based on Capability Token Validity for Secure IoT: Implementation and Evaluation	13

Data Aggregation Mechanisms on the Internet of Things: A Systematic Literature Review	13
AI-based fog and edge computing: A systematic review, taxonomy and future directions	13
GSTR: Secure multi-hop message dissemination in connected vehicles using social trust model	13
PoWaP: Proof of Work at Proximity for a crowdsensing system for collaborative traffic information gathering	12
COP: An integrated Communication, Optimization, and Prediction unit for smart Plug-in Electric Vehicle Charging	12
Publish–Subscribe approaches for the IoT and the cloud: Functional and performance evaluation of open-source systems	12
Faster and efficient cloud-server-aided data de-duplication scheme with an authenticated key agreement for Industrial Internet-of-Things	12
Lightweight and host-based denial of service (DoS) detection and defense mechanism for resource-constrained IoT devices	12
Intelligent wearable heart rate sensor implementation for in-vehicle infotainment and assistance	11
Enhancing the sensitivity of a chaos sensor for Internet of things	11
Hybrid MAC Protocol for UAV-Assisted Data Gathering in a Wireless Sensor Network	11
DevOps Contract for Assuring Execution of IoT Microservices in the Edge	11
A systematic review of technologies and solutions to improve security and privacy protection of citizens in the smart city	11
Inception convolutional vision transformers for plant disease identification	11
AnoML-IoT: An end to end re-configurable multi-protocol anomaly detection pipeline for Internet of Things	10
Scalability analysis of multiple LoRa gateways using stochastic geometry	10
Deep-learning approach to attack handling of IoT devices using IoT-enabled network services	10
A general architecture for a real-time monitoring system based on the internet of things	10
Secure and scalable access control protocol for IoT environment	10
Detection of malicious javascript on an imbalanced dataset	10
Multi-hop communication protocol for LoRa with software-defined networking extension	10
Multifactor authentication scheme using physically unclonable functions	10
IoT technologies for Augmented Human: A survey	10
A lightweight blockchain and fog-enabled secure remote patient monitoring system	10
IoT node selection in Opportunistic Networks: Implementation of fuzzy-based simulation systems and testbed	10
Static detection of malicious PowerShell based on word embeddings	10
A survey on blockchain, SDN and NFV for the smart-home security	10
OKIoT: Trade off analysis of smart speaker architecture on open knowledge IoT project	10
Decepti-SCADA: A cyber deception framework for active defense of networked critical infrastructures	9
A power-efficient audio acquisition system for smart city applications	9
A Two-layer Fog-Cloud Intrusion Detection Model for IoT Networks	9
Context-driven detection of distracted driving using images from in-car cameras	9
Low cost cloud based remote microscopy for biological sciences	9
Locally reconfigurable Self Organizing Feature Map for high impact malicious tasks submission in Mobile Crowdsensing	9
Non-functional requirements elicitation for edge computing	9
A Communication Scheme based on Fractional Order Chaotic Laser for Internet of Things	9
A review on the edge caching mechanisms in the mobile edge computing: A social-aware perspective	9
A deep learning approach for intrusion detection in Internet of Things using focal loss function	9
An improved PRoPHET - Random forest based optimized multi-copy routing for opportunistic IoT networks	9
Internet of Things-enabled Passive Contact Tracing in Smart Cities	9
iCovidCare: Intelligent health monitoring framework for COVID-19 using ensemble random forest in edge networks	9
Analysis of the constrained application protocol over quick UDP internet connection transport	9
FEACS: A fog enhanced expressible access control scheme with secure services delegation among carers in E-health systems	9
Quality attributes in edge computing for the Internet of Things: A systematic mapping study	9
Pareto optimal design space exploration of cyber-physical systems	9
A novel solution for counterfeit prevention in the wine industry based on IoT, smart tags, and crowd-sourced information	9
Fog-based local and remote policy enforcement for preserving data privacy in the Internet of Things	9
A solution for water management and leakage detection problems using IoTs based approach	9
Multi-UAV Allocation Framework for Predictive Crime Deterrence and Data Acquisition	9
HunterPlus: AI based energy-efficient task scheduling for cloud–fog computing environments	9
OPC UA Realization for simplified commissioning of adaptive sensing applications for the 5G IIoT	9
Secure firmware Over-The-Air updates for IoT: Survey, challenges, and discussions	9
Deep learning-enabled anomaly detection for IoT systems	8
Probabilistic computation offloading for mobile edge computing in dynamic network environment	8
Evaluation of end user requirements for Smart Home applications and services based on a decision support system	8
An overview of IoT architectures, technologies, and existing open-source projects	8
IoT-based freezing of gait detection using grey relational analysis	8
An optimized CNN-based intrusion detection system for reducing risks in smart farming	8
Conceptualization and scalable execution of big data workflows using domain-specific languages and software containers	8
Optimizing energy consumption in WSN-based IoT using unequal clustering and sleep scheduling methods	8
Customized novel routing metrics for wireless mesh-based swarm-of-drones applications	8
IRON: Reliable domain specific language for programming IoT devices	8
Advanced digital signatures for preserving privacy and trust management in hierarchical heterogeneous IoT: Taxonomy, capabilities, and objectives	8
A Secure Anonymous D2D Mutual Authentication and Key Agreement Protocol for IoT	8
Evaluating the performance of the OSCORE security protocol in constrained IoT environments	8
A jamming attack detection technique for opportunistic networks	7
CONFRONT: Cloud-fog-dew based monitoring framework for COVID-19 management	7
Synchronization and efficient channel hopping for power efficiency in LoRa networks: A comprehensive study	7
An IoT-based interoperable architecture for wireless biomonitoring of patients with sensor patches	7
IoT cloud laboratory: Internet of Things architecture for cellular biology	7
A machine-learning ensemble model for predicting energy consumption in smart homes	7
Advanced contribution of IoT in agricultural production for the development of smart livestock environments	7
Cross-Referencing Method for Scalable Public Blockchain	7
TGSM: Towards trustworthy group-based service management for social IoT	7
End-to-end anytime solution for appliance recognition based on high-resolution current sensing with few-shot learning	7
LAMD: Location-based Alert Message Dissemination scheme for emerging infrastructure-based vehicular networks	7
Wireless Sensor Network coverage optimization based on Yin–Yang pigeon-inspired optimization algorithm for Internet of Things	7
Advanced digital forensics and anti-digital forensics for IoT systems: Techniques, limitations and recommendations	7
A comprehensive review on detection of cyber-attacks: Data sets, methods, challenges, and future research directions	7
Lightweight rogue access point detection algorithm for WiFi-enabled Internet of Things(IoT) devices	7
OPIIoT: Design and Implementation of an Open Communication Protocol Platform for Industrial Internet of Things	7
Internet of things-assisted architecture for QRS complex detection in real time	6
Data reduction in fog computing and internet of things: A systematic literature survey	6
Reinforcement learning-based fuzzy geocast routing protocol for opportunistic networks	6
SCADA intrusion detection scheme exploiting the fusion of modified decision tree and Chi-square feature selection	6
The design of secure IoT applications using patterns: State of the art and directions for research	6
Sensors as the Basis for Digitalization: New Approaches in Instrumentation, IoT-concepts, and 5G	6
Mobile shared resources in the context of IoT low power lossy networks	6
The Internet of Autonomous Things applications: A taxonomy, technologies, and future directions	6
Seamless integration of devices in industry 4.0 environments	6
Assistance via IoT networking cameras and evidence theory for 3D object instance recognition: Application for the NAO humanoid robot	6
Blockchain-assisted internet of things framework in smart livestock farming	6
Multi-user searchable encryption voice in home IoT system	6
ACS: Accuracy-based client selection mechanism for federated industrial IoT	6
IoT architecture for continuous long term monitoring: Parkinson’s Disease case study	6
Planning optimization and stochastic analysis of RE-DGs for techno-economic benefit maximization in distribution networks	6
Resource efficient sensor fusion by knowledge-based network pruning	6
Low-cost wireless condition monitoring system for an ultracold atom machine	6
Design of a Trustless Smart City system: The #SmartME experiment	6
Internet-of-Things and fog-computing as enablers of new security and privacy threats	6
Machine learning enabled tools and methods for indoor localization using low power wireless network	6
A survey study on trust-based security in Internet of Things: Challenges and issues	6
Distributed compressive and collaborative sensing data collection in mobile sensor networks	6
FPMIPv6-S: A new network-based mobility management scheme for 6LoWPAN	6
802.11g Signal Strength Evaluation in an Industrial Environment	5
A secure and distributed architecture for vehicular cloud	5
Deriving event data sharing in IoT systems using formal modelling and analysis	5
Automated detection of unstructured context-dependent sensitive information using deep learning	5
Designing resource-constrained neural networks using neural architecture search targeting embedded devices	5
Integrating blockchain into supply chain safeguarded by PUF-enabled RFID	5
AgroLens: A low-cost and green-friendly Smart Farm Architecture to support real-time leaf disease diagnostics	5
Co-authorship network and the correlation with academic performance	5
ESRRA-IoT: Edge-based spatial redundancy reduction approach for Internet of Things	5
Social change: A comparative analysis of the impact of the IoT in Japan, Germany and Australia	5
Is the Internet of Things a helpful employee? An exploratory study of discourses of Canadian farmers	5
Building structural analysis based Internet of Things network assisted earthquake detection	5
Security issues in IoT applications using certificateless aggregate signcryption schemes: An overview	5
FogAI: An AI-supported fog controller for Next Generation IoT	5
Data acquisition and monitoring system framed in Industrial Internet of Things for PEM hydrogen generators	5
Evaluation of corporate requirements for smart manufacturing systems using predictive analytics	5
Development of a self-powered wireless sensor node to measure the water flowrate by using a turbine flowmeter	5
“Hey Alexa, what do you know about the COVID-19 vaccine?”— (Mis)perceptions of mass immunization and voice assistants	5
Comparative link-level analysis and performance estimation of channel models for IIoT (Industrial-IoT) wireless communications	5
Confidential computing in cloud/fog-based Internet of Things scenarios	5
OpenAPI framework for the Web of Things	5
Lossy Data Compression for IoT Sensors: A Review	5
Proactive trust classification for detection of replication attacks in 6LoWPAN-based IoT	5
A new DTN routing strategies ensuring high message delivery ratio while keeping low power consumption	5
DTCMS: Dynamic traffic congestion management in Social Internet of Vehicles (SIoV)	5
PaFiR: Particle Filter Routing – A predictive relaying scheme for UAV-assisted IoT communications in future innovated networks	5
SCGR: Self-configuring greedy routing for minimizing routing interrupts in vehicular communication networks	5
ESco: Eligibility score-based strategy for sensors selection in CR-IoT: Application to LoRaWAN	5
An Integrated Fuzzy-based Admission Control System (IFACS) for 5G Wireless Networks: Its implementation and performance evaluation	5
Capability token selection algorithms to implement lightweight protocols	5
Mining and IoT-based Vehicle Ad-hoc NETwork: Industry opportunities and innovation	5
A Collaboration-centric Taxonomy of the Internet of Things: Implications for Awareness Support	4
A feasibility study of multi-mode intelligent fusion medical data transmission technology of industrial Internet of Things combined with medical Internet of Things	4
Energy consumption of on-device machine learning models for IoT intrusion detection	4
Research on lightweight Yolo coal gangue detection algorithm based on resnet18 backbone feature network	4
Performance evaluation of data replication protocol based on Cuckoo search in mobile ad-hoc networks	4
Ultrasonic physical layers as building blocks of IoT stacks	4
A comprehensive pseudonym changing scheme for improving location privacy in vehicular networks	4
A review of IoT systems to enable independence for the elderly and disabled individuals	4
Security and privacy-preserving in e-health: A new framework for patient	4
Securing massive IoT in 6G: Recent solutions, architectures, future directions	4

Efficient job scheduling paradigm based on hybrid sparrow search algorithm and differential evolution optimization for heterogeneous cloud computing platforms	4
A comparison of mechanisms for RTC in the context of IoT	4
Online reverse engineering of CAN data	4
A systematic literature review on attacks defense mechanisms in RPL-based 6LoWPAN of Internet of Things	4
Internet of Things Design, Architectures and Protocols	4
Effect of vehicle technical condition on real-time driving risk management in Internet of Vehicles: Design and performance evaluation of an integrated fuzzy-based system	4
Addressing the cybersecurity vulnerabilities of advanced nanogrids: A practical framework	4
CREASE: Certificateless and REused-pseudonym based Authentication Scheme for Enabling security and privacy in VANETs	4
An integrated solution of software and hardware for environmental monitoring	4
GROLL: Geographic Routing for Low Power and Lossy IoT Networks	4
Generating an environmental awareness system for learning using IoT technology	4
TADR-EAODV: A trust-aware dynamic routing algorithm based on extended AODV protocol for secure communications in wireless sensor networks	4
A deep learning-based cow behavior recognition scheme for improving cattle behavior modeling in smart farming	4
ModularFed: Leveraging modularity in federated learning frameworks	4
A survey on device fingerprinting approach for resource-constraint IoT devices: Comparative study and research challenges	4
Web-Based 3D and 360∘	4
IoT-based prediction models in the environmental context: A systematic Literature Review	4
IoFT-FIS: Internet of farm things based prediction for crop pest infestation using optimized fuzzy inference system	4
A deep learning framework for target localization in error-prone environment	4