# A Survey from Real-Time to Near Real-Time Applications in Fog Computing Environments
## 3 Classification of Articles
### Low Latency  
Of the 95 selected articles, 13 belong to the low latency category. This category includes articles that conceptualize real-time systems as being systems that provide low latency. [PERSON] et al. [60] propose an architecture of communication between vehicles. The implementation uses the Dedicated Short Range Communication (DSRC) as wireless technology and fog computing framework as the basis for the whole architecture. In addition, it utilizes the Wireless Power Transfer (WPT) system for real-time data transfer. [PERSON] et al. [61]'s article proposes a system called Cloud/Crowd System that integrates large-scale aggregated and retrieved data into the fog layer. Fog architecture is used since it offers low latency in data processing and storage and allows for geographic location recognition and real-time operations. The purpose of this system is environmental monitoring for early warning system for disaster prevention. In [PERSON] et al. [62]'s article, a real-time notification protocol called RT-Notification is proposed for applications requiring wireless control. RT-Notification provides low latency TDMA communication between an access point in the fog and portable monitoring devices. [PERSON] et al. [63] propose a mobility support approach to Wi-Fi based real-time health monitoring systems through an efficient handover mechanism. The handover mechanism helps maintain the connection between the sensor nodes and the low latency system. The proposed approach allows objects and people to be monitored remotely in real-time without any interruption during mobility. [PERSON] and [PERSON] [64] propose a distributed approach for mobile devices to reliably, and real-time transmit data into the vehicle network through cloud-fog computing. The purpose of the approach is to enable QoS in real-time transmission and impartiality of resource reservation between mobile devices. [PERSON] et al. [65] propose an architecture based on three layers: IoV, fog computing, and cloud computing. For the fog computing layer, a framework has been developed to collect and process real-time events generated by intelligent vehicles, as well as view the state of vehicle traffic at each stretch of the road. [PERSON] et al. [66]'s article provides the details of the real-time implementation of a Deviceto-Device (D2D) based Mobile Edge Fog Computing system. The purpose of the proposal is to explore the benefits of the D2D model by incorporating D2D functionality into the proposed relay gateways. [PERSON] et al. [67] propose a cyber-manufacturing system based on the fog computing approach. The goal of the proposed system is to provide real-time remote sensing, monitoring and scalable, high-performance computing for prognostics and diagnostics. In addition to the fog infrastructure, the system uses wireless sensor networks, cloud computing, and machine learning. [PERSON] et al. [68]'s research proposes an architecture of an obstructive sleep apnea monitoring system based on IoT and big data approaches. The proposed three-tier architecture integrates the characteristics of fog and cloud computing to provide sleep apnea diagnosis and treatment. For this, a variety of services, namely remote monitoring, real-time alert notifications, data analysis, and information visualization, are included. [PERSON] et al. [69] propose a data management platform to monitor and control web/mobile IoT layer applications using IPv4/IPv6 and higher layer protocols such as CoAP, HTTP, and WebSocket. The proposed platform allows the detection of anomalies in IoT devices and real-time error reporting mechanisms. [PERSON] et al. [70] propose a smart street lamp (SSL) mechanism based on the concept of fog computing for smart cities. The proposed SSL consists of three main parts: an intelligent sensor street lamp, which can adjust the lamp brightness autonomously; a network used for real-time communication between the manager and the lampposts; and a management platform to notify of lamp breakage and automatically send an employee to service. [PERSON] et al.