Gyu Myoung Lee

Software defined networking-based vehicular Adhoc Network with Fog Computing

Vehicular Adhoc Networks (VANETs) have been attracted a lot of research recent years. Although VANETs are deployed in reality offering several services, the current architecture has been facing many difficulties in deployment and management because of poor connectivity, less scalability, less flexibility and less intelligence. We propose a new VANET architecture called FSDN which combines two emergent computing and network paradigm Software Defined Networking (SDN) and Fog Computing as a prospective solution. SDN-based architecture provides flexibility, scalability, programmability and global knowledge while Fog Computing offers delay-sensitive and location-awareness services which could be satisfy the demands of future VANETs scenarios. We figure out all the SDN-based VANET components as well as their functionality in the system. We also consider the system basic operations in which Fog Computing are leveraged to support surveillance services by taking into account resource manager and Fog orchestration models. The proposed architecture could resolve the main challenges in VANETs by augmenting Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), Vehicle-to-Base Station communications and SDN centralized control while optimizing resources utility and reducing latency by integrating Fog Computing. Two use-cases for non-safety service (data streaming) and safety service (Lane-change assistance) are also presented to illustrate the benefits of our proposed architecture.

Semantic Context-Aware Service Composition for Building Automation System

Service-oriented architecture (SOA) is realized by independent, standardized, and self-describing units known as services. This architecture has been widely used and verified for automatic, dynamic, and self-configuring distributed systems such as in building automation. This paper presents a building automation system adopting SOA paradigm with devices implemented by device profile for web service (DPWS) in which context information is collected, processed, and sent to a composition engine to coordinate appropriate devices/services based on the context, composition plan, and predefined policy rules. A six-phased composition process is proposed to carry out the task. In addition, two other components are designed to support the composition process: building ontology as a schema for representing semantic data and composition plan description language to describe context-based composite services in form of composition plans. A prototype consisting of a DPWSim simulator and SamBAS is developed to illustrate and test the proposed idea. Comparison analysis and experimental results imply the feasibility and scalability of the system.

On teletraffic applications to OBS

We provide teletraffic models for loss probability evaluation of optical burst switching (OBS). We show that the popular Engset formula is not exact for OBS modeling and demonstrate that in certain cases it is not appropriate. A new exact model is provided. The various models are compared using numerical results for various OBS alternatives with and without burst segmentation.

Performance evaluation of an optical hybrid switching system

We propose a new optical hybrid switching system that takes advantage of both optical burst switching (OBS) and optical circuit switching (OCS) technologies. This system classifies incoming IP traffic flows into short-lived and long-lived flows. We model the system as a single server queue in a Markovian environment. The burst generation process is assumed to follow a two-state Markov modulated Poisson process (MMPP), and the service rate fluctuates based on the number of concurrent OCS sessions. Results for the mean delay and queue size are derived.

Adaptive Delay-Aware Energy Efficient TDM-PON

Passive Optical Networks (PONs) are widely adopted as the last-mile technology due to the large bandwidth capacity it provides to end users. In addition, PON is viewed as a green access technology since it reduces energy consumption compared to other access technologies (e.g. Fiber to the Node). However, there is still room for enhancing the energy efficiency of PON further, and we can find many attempts along those lines in academia and industry. A widely used approach to save energy in Time Division Multiplexing (TDM)-PON is to keep the Optical Network Units (ONUs) in sleep mode when they do not have anything to receive or transmit. However, sleep intervals have a direct negative impact on increasing traffic delay. Therefore, energy efficiency in a TDM-PON presents a clear trade-off: the longer an ONU sleeps, the less energy it consumes, but the higher the delay experienced by the downlink traffic, and vice versa. In this paper, we propose an Adaptive Delay-Aware Energy Efficient (ADAEE) TDM-PON solution. The ADAEE aims at saving as much energy as possible while meeting the PON access delay restrictions imposed by the operator. We evaluate our solution in terms of energy consumption and delay performance using real traffic traces. The results demonstrate that the proposed solution can meet delay requirements while being more energy efficient solution compared to the existing solutions.

Functional Architecture for NGN-Based Personalized IPTV Services

IPTV is one of the most highly visible services to emerge as part of the development of next generation network (NGN). IPTV services over manageable broadband link from a provider will be one of the ultimate goals of the broadband revolution using NGN. In this paper, we analyze IPTV architecture developed by ITU-T and provide functional architecture for NGN-based IPTV services according to functional mapping between IPTV and NGN. For this, we provide the detailed functional architecture and relevant operations with other functional blocks and present the harmonized architecture between IPTV and NGN for NGN-based IPTV services with the alignment with existing NGN architecture. As challenging architectural issues, we also introduce personalized IPTV services based on Web-based open platform in NGN environment and illustrate functional architecture and service examples for Web-based personalized IPTV services.

DPWSim: A simulation toolkit for IoT applications using devices profile for web services

The OASIS standard Devices Profile for Web Services (DPWS) enables the use of Web services on smart and resource-constrained devices, which are the cornerstones of the Internet of Things (IoT). DPWS sees a perspective of being able to build service-oriented and event-driven IoT applications on top of these devices with secure Web service capabilities and a seamless integration into existing World Wide Web infrastructure. We introduce DPWSim, a simulation toolkit to support the development of such applications. DPWSim allows developers to prototype, develop, and test IoT applications using the DPWS technology without the presence of physical devices. It also can be used for the collaboration between manufacturers, developers, and designers during the new product development process.

Service composition for IP smart object using realtime Web protocols

The Internet of Things (IoT) refers to a world-wide network of interconnected physical things using standardized communication protocols. Recent advancements in IoT protocol stack unveil a possibility for the future IoT based on the stable and scalable Internet Protocol (IP). Then, how can data and events introduced by IP networked things be efficiently exchanged and aggregated in various application domains? The problem, known as service composition, is essential to support the rapid creation of new ubiquitous applications. This article explains the practicability of the future full-IP IoT with realtime Web protocols and discusses the research challenges of service composition. Identify future full-IP IoT with IP smart object using realtime Web protocolState the problem of service composition problem in the future IoTReview the state of the art of service composition in the future IoTProvide research challenges of service composition in the future IoT

Evaluating Energy Efficiency of ONUs Having Multiple Power Levels in TDM-PONs

A TDM Passive Optical Network (TDM-PON) proposes the use of sleep modes for Optical Network Units (ONUs) to maximize Energy Efficiency (EE). When an ONU manages a sleep mode, it needs to turn on and off some of its components based on communication requirements. Hence, an ONU ends up with multiple power levels. Existing analytical models for evaluating EE consider that an ONU has only two power levels. However, we have found in some literature where an ONU can have more than two power levels. In this letter we propose an analytical model to quantify the EE of an ONU having more than two power levels. We demonstrate the accuracy of the model by means of simulation under two different sleep interval deciding algorithms.

A semantic enhanced service exposure model for a converged service environment

Service exposure, as a prerequisite for the reuse of existing services, plays a significant role in next-generation service delivery. However, some issues such as cross-domain interoperability and user-centricity are still unresolved. Therefore, this article proposes a semantic enhanced converged service exposure model that enables services derived from different domains (i.e., telecom/web/device/user) to be integrated into a composite service regardless of their underlying heterogeneities. Meanwhile, the user-centric feature is enhanced by applying the semantic annotation to both the service description and the user request, as well as empowering a user to publish and share his/her created service in a user-friendly way. Moreover, a variety of interfaces, including APIs, widgets, and natural-language-based tools, are provided to satisfy the multilevel user requirements, enabling users to profit from a highly personalized, meaningful communication and interaction experience.