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- Sungrae Cho is a professor with the school of computer science and engineering, Chung-Ang University (CAU), Seoul. Pr... moreSungrae Cho is a professor with the school of computer science and engineering, Chung-Ang University (CAU), Seoul. Prior to joining CAU, he was an assistant professor with the department of computer sciences, Georgia Southern University, Statesboro, GA, USA, from 2003 to 2006, and a senior member of technical staff with the Samsung Advanced Institute of Technology (SAIT), Kiheung, South Korea, in 2003. From 1994 to 1996, he was a research staff member with electronics and telecommunications research institute (ETRI), Daejeon, South Korea. From 2012 to 2013, he held a visiting professorship with the national institute of standards and technology (NIST), Gaithersburg, MD, USA. He received the B.S. and M.S. degrees in electronics engineering from Korea University, Seoul, South Korea, in 1992 and 1994, respectively, and the Ph.D. degree in electrical and computer engineering from the Georgia Institute of Technology, Atlanta, GA, USA, in 2002.
His current research interests include wireless networking, ubiquitous computing, and ICT convergence. He was an editor of Ad Hoc Networks Journal (Elsevier) from 2012 to 2017. He has served numerous international conferences as an organizing committee chair, such as IEEE SECON, ICOIN, ICTC, ICUFN, TridentCom, and the IEEE MASS, and as a program committee member, such as IEEE ICC, MobiApps, SENSORNETS, and WINSYS.edit - Ian F. Akyildizedit
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Live video streaming services have experienced significant growth since the emergence of social networking paradigms in recent years. In this scenario, adaptive bitrate streaming communications transmitted on web protocols provide a... more
Live video streaming services have experienced significant growth since the emergence of social networking paradigms in recent years. In this scenario, adaptive bitrate streaming communications transmitted on web protocols provide a convenient and cost-efficient facility to serve various multimedia platforms over the Internet. In these communication models, video content is delivered optimally, possibly transcoded, edited automatically, and cached temporarily by network elements along the path. To this end, the computational capabilities of various network elements are considered as major resources to be optimized for service quality improvements. This article provides a contemporary survey of cutting-edge live video streaming studies from a computation-driven perspective. First, an overview of the global standards, system architectures, and streaming protocols is presented. Next, hierarchical computation-driven models of live video streaming are anatomized, including cloud-, edge-,...
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Demand-side management program is important for future smart grid. Most of the DSM program developed in the past interact customer and utility company. We suggest the Factory Management System using Social Internet of Things. It is not... more
Demand-side management program is important for future smart grid. Most of the DSM program developed in the past interact customer and utility company. We suggest the Factory Management System using Social Internet of Things. It is not interaction between customer and utility company but interaction between things and things. Therefore we propose a autonomous demand-side management system and a system architecture.
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Unmanned aerial vehicle (UAV) communication is regarded as a promising technology for lightweight Internet of Things (IoT) communications in narrowband-IoT (NB-IoT) systems deployed in rugged terrain. In such UAV-assisted NB-IoT systems,... more
Unmanned aerial vehicle (UAV) communication is regarded as a promising technology for lightweight Internet of Things (IoT) communications in narrowband-IoT (NB-IoT) systems deployed in rugged terrain. In such UAV-assisted NB-IoT systems, the optimal UAV placement and resource allocation play a critical role. Consequently, the joint optimization of the UAV placement and resource allocation is considered in this study to improve the system capacity. Because the considered optimization problem is an NP-hard problem and owing to its non-convex property, it is difficult to optimize both the UAV placement and resource allocation simultaneously. Therefore, a competitive clustering algorithm has been developed by exchanging strategies between the UAV and the adjacent IoT devices to optimize the UAV placement. With multiple iterations, the UAV and the IoT devices within the coverage area of the UAV, converge their clustering strategies, which are suboptimal, to satisfy both sides. The border...
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Constructionsafety education plays a vital rolein equipping studentswithconcrete safety knowledge and promoting safetyperformance prior to entering construction sites. However, safety topics are not given adequate attention in... more
Constructionsafety education plays a vital rolein equipping studentswithconcrete safety knowledge and promoting safetyperformance prior to entering construction sites. However, safety topics are not given adequate attention in mostconstruction curricula and traditional pedagogic tools fail to provide practical experience or sufficiently engage students inacquiring safety knowledge. With this regard, this study proposes the VIrtual FIeld Trip System (VIFITS) for mobileconstruction safety education using a 360-degree panoramic virtual reality. The VIFITS utilizes a state-of-the-art 360-degree panorama-based Virtual Reality technology in order to bring construction field trips to the classroom and providepractical experience to improve students’ safety knowledge. VIFITS consists of three modules: (1) a Safety InformationDissemination module (SID) in which the educator disseminates safety information to the students through mobilelearning; (2) a Virtual Field Trip Experience module (FTE...
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In smart manufacturing, production machinery and auxiliary devices, referred to as industrial Internet of things (IIoT), are connected to a unified networking infrastructure for management and command deliveries in a precise production... more
In smart manufacturing, production machinery and auxiliary devices, referred to as industrial Internet of things (IIoT), are connected to a unified networking infrastructure for management and command deliveries in a precise production process. However, providing autonomous, reliable, and real-time offloaded services for such a production is an open challenge since these IIoT devices are assumed lightweight embedded platforms with limited computing performance. In this paper, we propose a pattern-identified online task scheduling (PIOTS) mechanism for the networking infrastructure, where multitier edge computing is provided, in order to handle the offloaded tasks in real time. First, historical IIoT task patterns in every timeslot are used to train a self-organizing map (SOM), which represents the features of the task patterns within defined dimensions. Consequently, offline task scheduling among edge computing-enabled entities is performed on the set of all SOM neurons using the Hu...
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Recently, mobile edge computing (MEC) technology was developed to mitigate the overload problem in networks and cloud systems. An MEC system computes the offloading computation tasks from resource-constrained Internet of Things (IoT)... more
Recently, mobile edge computing (MEC) technology was developed to mitigate the overload problem in networks and cloud systems. An MEC system computes the offloading computation tasks from resource-constrained Internet of Things (IoT) devices. In addition, several convergence technologies with renewable energy resources (RERs) such as photovoltaics have been proposed to improve the survivability of IoT systems. This paper proposes an MEC integrated with RER system, which is referred to as energy-harvesting (EH) MEC. Since the energy supply of RERs is unstable due to various reasons, EH MEC needs to consider the state-of-charge (SoC) of the battery to ensure system stability. Therefore, in this paper, we propose an offloading scheduling algorithm considering the battery of EH MEC as well as the service quality of experience (QoE). The proposed scheduling algorithm consists of a two-stage operation, where the first stage consists of admission control of the offloading requests and the ...
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Hazard investigation education plays a crucial role in equipping students with adequate knowledge and skills to avoid or eliminate construction hazards at workplaces. With the emergence of various visualization technologies, virtual... more
Hazard investigation education plays a crucial role in equipping students with adequate knowledge and skills to avoid or eliminate construction hazards at workplaces. With the emergence of various visualization technologies, virtual photoreality as well as 3D virtual reality have been adopted and proved advantageous to various educational disciplines. Despite the significant benefits of providing an engaging and immersive learning environment to promote construction education, recent research has also pointed out that virtual photoreality lacks a 3D object anatomization tools to support learning, while 3D-virtual reality cannot provide a real-world environment. In recent years, research efforts have studied virtual reality applications separately, and there is a lack of research integrating these technologies to overcome limitations and maximize advantages for enhancing learning outcomes. In this regard, the paper develops a construction hazard investigation system leveraging object...
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Research Interests: Evolutionary Biology, Computer Science, Algorithms, Ecology, Energy Consumption, and 15 moreInternet of Things, Energy efficiency, Medicine, Algorithm, Multidisciplinary, LTE, Computer Simulation, Network evolution, Energy Efficiency, Machine Type Communication, Internet, Amcs, Health Resources, Mtc, and core technologies
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2.4GHz Industrial Scientific Medical(ISM) Band is shared by both WLAN and IEEE 802.15.4. Therefore, WLAN and IEEE 802.15.4 get interfered by each other where WLAN and IEEE 802.15.4 deploy locally. Especially, IEEE 802.15.4 devices are... more
2.4GHz Industrial Scientific Medical(ISM) Band is shared by both WLAN and IEEE 802.15.4. Therefore, WLAN and IEEE 802.15.4 get interfered by each other where WLAN and IEEE 802.15.4 deploy locally. Especially, IEEE 802.15.4 devices are more influenced by the interference from LWAN devices because WLAN devices transmit data with higher power than IEEE 802.15.4 devices. In this paper, we proposed a possible algorithm for interference coordination in the Heterogeneous Network (HetNet) and optimized an important parameter, NAV, of the proposed mechanism. Our goal is to mitigate the interference problem and to make IEEE 802.15.4 work properly while minimizing the loss of WLAN by making PAN Coordinator conduct the role of both WLAN and IEEE 802.15.4 devices.
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Research Interests: Computer Science, Algorithms, Workflow, Computer Security, Infectious Diseases, and 13 moreMedicine, Multidisciplinary, OpenFlow, Software, ASP, Computer Network, Software defined networking, PLoS one, MPLS, Computer communication networks, DoS attacks, Denial of Service Attack, and Multi Protocol Label Switching
Sensor fusion techniques have made a significant contribution to the success of the recently emerging mobile applications era because a variety of mobile applications operate based on multi-sensing information from the surrounding... more
Sensor fusion techniques have made a significant contribution to the success of the recently emerging mobile applications era because a variety of mobile applications operate based on multi-sensing information from the surrounding environment, such as navigation systems, fitness trackers, interactive virtual reality games, etc. For these applications, the accuracy of sensing information plays an important role to improve the user experience (UX) quality, especially with gyroscopes and accelerometers. Therefore, in this paper, we proposed a novel mechanism to resolve the gyro drift problem, which negatively affects the accuracy of orientation computations in the indirect Kalman filter based sensor fusion. Our mechanism focuses on addressing the issues of external feedback loops and non-gyro error elements contained in the state vectors of an indirect Kalman filter. Moreover, the mechanism is implemented in the device-driver layer, providing lower process latency and transparency capa...
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Serviceability is the ability of a network to serve user equipments (UEs) within desired requirements (e.g., throughput, delay, and packet loss). High serviceability is considered as one of the key foundational criteria toward a... more
Serviceability is the ability of a network to serve user equipments (UEs) within desired requirements (e.g., throughput, delay, and packet loss). High serviceability is considered as one of the key foundational criteria toward a successful fog radio access infrastructure satisfying the Internet of Things paradigm in the 5G era. In this paper, we propose an adaptive resource balancing (ARB) scheme for serviceability maximization in fog radio access networks wherein the resource block (RB) utilization among remote radio heads (RRHs) are balanced using the backpressure algorithm with respect to a time-varying network topology issued by potential RRH mobilities. The optimal UE selection for service migration from a high-RB-utilization RRH to its neighboring low-RB-utilization RRHs is determined by the Hungarian method to minimize RB occupation after moving the service. Analytical results reveal that the proposed ARB scheme provides substantial gains compared with the standalone capacity-aware, max-rate, and cache-aware UE association approaches in terms of serviceability, availability, and throughput. INDEX TERMS Fog radio access network (F-RAN), mobile remote radio head (RRH), resource balancing, serviceability maximization, Hungarian method, backpressure algorithm.
Serviceability is the ability of a network to serve user equipments (UEs) within desired requirements (e.g., throughput, delay, and packet loss). High serviceability is considered as one of the key foundational criteria toward a... more
Serviceability is the ability of a network to serve user equipments (UEs) within desired requirements (e.g., throughput, delay, and packet loss). High serviceability is considered as one of the key foundational criteria toward a successful fog radio access infrastructure satisfying the Internet of Things paradigm in the 5G era. In this paper, we propose an adaptive resource balancing (ARB) scheme for serviceability maximization in fog radio access networks wherein the resource block (RB) utilization among remote radio heads (RRHs) are balanced using the backpressure algorithm with respect to a time-varying network topology issued by potential RRH mobilities. The optimal UE selection for service migration from a high-RB-utilization RRH to its neighboring low-RB-utilization RRHs is determined by the Hungarian method to minimize RB occupation after moving the service. Analytical results reveal that the proposed ARB scheme provides substantial gains compared with the standalone capacity-aware, max-rate, and cache-aware UE association approaches in terms of serviceability, availability, and throughput. INDEX TERMS Fog radio access network (F-RAN), mobile remote radio head (RRH), resource balancing, serviceability maximization, Hungarian method, backpressure algorithm.
Demand response technology is a key technology for distributing electricity tasks in response to electricity prices in a smart grid system. In the current demand response research, there has been much demand for an automated energy... more
Demand response technology is a key technology for distributing electricity tasks in response to electricity prices in a smart grid system. In the current demand response research, there has been much demand for an automated energy scheduling scheme that uses smart devices for residential customers in the smart grid. In this paper, two automated energy scheduling schemes are proposed for residential smart grid demand response systems: semi-automated scheduling and fully-automated scheduling. If it is possible to set the appliance preference, semi-automated scheduling will be conducted, and if it is impossible, fully-automated scheduling will be operated. The formulated optimization problems consider the electricity bill along with the user convenience. For the fully-automated scheduling, the appliance preference can automatically be found according to appliance type from the electricity consumption statistics. A performance evaluation validates that the proposed scheme shifts operation to avoid peak load, that the electricity bill is significantly reduced, and that user convenience is satisfied.
The emergence of social networking and proximity services is driving the Internet-of-Things (IoT) paradigms toward a location-aware connecting society. To prepare for such a booming paradigm, IEEE 802.15.8 standardizes peer-aware... more
The emergence of social networking and proximity services is driving the Internet-of-Things (IoT) paradigms toward a location-aware connecting society. To prepare for such a booming paradigm, IEEE 802.15.8 standardizes peer-aware communication (PAC) within the strict consideration of infrastructureless property and fully distributed coordination features. Since no central entity exists in a PAC network for control and management purposes, every PAC device (PD) plays an equal role in terms of communication. This situation leads to a variety of security challenges, especially in authentication and key agreement for lightweight IoT-enabled PDs. Recently, there are some proposals aimed at the aforementioned problems, such as approaches with personal identification number, physical layer features. However, due to its inconvenience and computational complexity for the lightweight IoT-enabled PDs, authentication and key agreement are still open issues in PAC. From this view, this paper proposes a new approach that utilizes social networking features closely tied to the PAC in order to support authentication and key agreement procedures. A number of trusted PDs are delegated to authenticate the requesting PD on behalf of the requested PD when an association is established between them. Intensive analysis and evaluation show that the proposed protocol provides multiple security levels as well as user convenience with reasonable resource consumption.
As Internet-of-Things (IoT) technology emerges, smart manufacturing has recently attracted a large amount of attention. Smart manufacturing leads to smart energy management because of its significant operating expenditure savings.... more
As Internet-of-Things (IoT) technology emerges, smart manufacturing has recently attracted a large amount of attention. Smart manufacturing leads to smart energy management because of its significant operating expenditure savings. However, it is believed that centralized energy management of IoT devices will impose critically large overhead since massive numbers of IoT devices are expected to be deployed. Therefore, distributed energy management or demand response (DR) is deemed to be a better solution for emerging massive smart manufacturing systems. There have been a significant number of distributed DR algorithms, including Stackelberg game theoretic approaches. However, the Stackelberg game theoretic approaches require a large number of iterations to reach Nash equilibrium, which in turn necessitates communication overheads among IoT devices. This communication overhead causes a large amount of energy consumption as well as delay. In this paper, we propose a lightweight DR scheme based on the Stackelberg model without iterations for the massive smart manufacturing systems. The proposed scheme manages energy consumption based on a non-iterative Stackelberg model and historical real-time pricing. To the best of our knowledge, our approach is the first technique that considers communication overheads for the DR technique. The performance evaluation demonstrates that the proposed scheme shifts operations to avoid peak loads, and the electricity bill is significantly reduced, operations occur at preferred times, and communication energy consumption and delay are minimized.
In smart manufacturing, production machinery and auxiliary devices, referred to as industrial Internet of things (IIoT), are connected to a unified networking infrastructure for management and command deliveries in a precise production... more
In smart manufacturing, production machinery and auxiliary devices, referred to as industrial Internet of things (IIoT), are connected to a unified networking infrastructure for management and command deliveries in a precise production process. However, providing autonomous, reliable, and real-time offloaded services for such a production is an open challenge since these IIoT devices are assumed lightweight embedded platforms with limited computing performance. In this paper, we propose a pattern-identified online task scheduling (PIOTS) mechanism for the networking infrastructure, where multitier edge computing is provided, in order to handle the offloaded tasks in real time. First, historical IIoT task patterns in every timeslot are used to train a self-organizing map (SOM), which represents the features of the task patterns within defined dimensions. Consequently, offline task scheduling among edge computing-enabled entities is performed on the set of all SOM neurons using the Hungarian method to determine the expected optimal task assignments. In real-time context, whenever a task arrives at the infrastructure, the expected optimal assignment for the task is scheduled to the appropriate edge computing-enabled entity. Numerical simulation results show that the proposed PIOTS mechanism overcomes existing solutions in terms of computation performance and service capability.
Construction safety education plays a crucial role in improving the safety performance in the construction industry. Many research works have successfully adopted computerized three-dimensional model-based virtual reality (3D-VR) to... more
Construction safety education plays a crucial role in improving the safety performance in the construction industry. Many research works have successfully adopted computerized three-dimensional model-based virtual reality (3D-VR) to provide students with adequate safety knowledge and skills before they enter construction sites. Despite the advantages of improving learning outcomes, 3D-VR has limitations not only in reflecting real-world visibility but also in consuming significant energy and requiring strict user–device compatibility. Therefore, this research methodology was initiated with a thorough investigation of VR application in construction safety education. On the basis of a literature review, the study subsequently analyzes the energy-consumption problems of conventional VR systems. Initial findings motivate the development of an energy-efficient learning system (the interactive constructive safety education (eCSE)) using Web-based panoramic virtual photoreality technology for interactive construction safety education. The eCSE system provides three key interactive modules, namely, lesson delivery (LD), practical experience (PE), and knowledge assessment (KA), for use in mobile devices. The trial system has been developed and validated through scenarios derived from real construction sites. The preliminary evaluation reveals that the eCSE system not only overcomes the 3D-VR limitations in terms of energy efficiency, user device adaptability, and easy implementation, but also improves learning usability.