24 research outputs found

    An adaptive physiology-aware communication framework for distributed medical cyber physical systems

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    For emergency medical cyber-physical systems, enhancing the safety and effectiveness of patient care, especially in remote rural areas, is essential. While the doctor to patient ratio in the United States is 30 to 10,000 in large metropolitan areas, it is only 5 to 10,000 in most rural areas; and the highest death rates are often found in the most rural counties. Use of telecommunication technologies can enhance effectiveness and safety of emergency ambulance transport of patients from rural areas to a regional center hospital. It enables remote monitoring of patients by the physician experts at the tertiary center. There are critical times during transport when physician experts can provide vital assistance to the ambulance Emergency Medical Technicians (EMT) to associate best treatments. However, the communication along the roads in rural areas can range irregularly from 4G to low speed 2G links, including some parts of routes with cellular network communication breakage. This unreliable and limited communication bandwidth together with the produced mass of clinical data and the many information exchanges pose a major challenge in real-time supervision of patients. In this study, we define the notion of distributed emergency care, and propose a novel adaptive physiology-aware communication framework which is aware of the patient condition, the underlying network bandwidth, and the criticality of clinical data in the context of the specific diseases. Using the concept of distributed medical CPS models, we study the semantics relation of communication Quality of Service (QoS) with clinical messages, criticality of clinical data, and an ambulance's undertaken route all in a disease-aware manner. Our proposed communication framework is aimed to enhance remote monitoring of acute patients during ambulance transport from a rural hospital to a regional center hospital. We evaluate the components of our framework through various experimentation phases including simulation, instrumentation, real-world profiling, and validation

    A Fog Computing Architecture for Disaster Response Networks

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    In the aftermath of a disaster, the impacted communication infrastructure is unable to provide first responders with a reliable medium of communication. Delay tolerant networks that leverage mobility in the area have been proposed as a scalable solution that can be deployed quickly. Such disaster response networks (DRNs) typically have limited capacity due to frequent disconnections in the network, and under-perform when saturated with data. On the other hand, there is a large amount of data being produced and consumed due to the recent popularity of smartphones and the cloud computing paradigm. Fog Computing brings the cloud computing paradigm to the complex environments that DRNs operate in. The proposed architecture addresses the key challenges of ensuring high situational awareness and energy efficiency when such DRNs are saturated with large amounts of data. Situational awareness is increased by providing data reliably, and at a high temporal and spatial resolution. A waypoint placement algorithm places hardware in the disaster struck area such that the aggregate good-put is maximized. The Raven routing framework allows for risk-averse data delivery by allowing the user to control the variance of the packet delivery delay. The Pareto frontier between performance and energy consumption is discovered, and the DRN is made to operate at these Pareto optimal points. The FuzLoc distributed protocol enables mobile self-localization in indoor environments. The architecture has been evaluated in realistic scenarios involving deployments of multiple vehicles and devices

    Software defined networking based resource management and quality of service support in wireless sensor network applications

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    To achieve greater performance in computing networks, a setup of critical computing aspects that ensures efficient network operation, needs to be implemented. One of these computing aspects is, Quality of Service (QoS). Its main functionality is to manage traffic queues by means of prioritizing sensitive network traffic. QoS capable networking allows efficient control of traffic especially for network critical data. However, to achieve this in Wireless Sensor Networks (WSN) is a serious challenge, since these technologies have a lot of computing limitations. It is even difficult to manage networking resources with ease in these types of technologies, due to their communication, processing and memory limitations. Even though this is the case with WSNs, they have been largely used in monitoring/detection systems, and by this proving their application importance. Realizing efficient network control requires intelligent methods of network management, especially for sensitive network data. Different network types implement diverse methods to control and administer network traffic as well as effectively manage network resources. As with WSNs, communication traffic and network resource control are mostly performed depending on independently employed mechanisms to deal with networking events occurring on different levels. It is therefore challenging to realize efficient network performance with guaranteed QoS in WSNs, given their computing limitations. Software defined networking (SDN) is advocated as a potential paradigm to improve and evolve WSNs in terms of capacity and application. A means to apply SDN strategies to these compute-limited WSNs, formulates software defined wireless sensor networks (SDWSN). In this work, a resource-aware OpenFlow-based Active Network Management (OF-ANM) QoS scheme that uses SDN strategies is proposed and implemented to apply QoS requirements for managing traffic congestion in WSNs. This scheme uses SDN programmability strategies to apply network QoS requirements and perform traffic load balancing to ensure congestion control in SDWSN. Our experimental results show that the developed scheme is able to provide congestion avoidance within the network. It also allows opportunities to implement flexible QoS requirements based on the systemโ€™s traffic state. Moreover, a QoS Path Selection and Resource-associating (Q-PSR) scheme for adaptive load balancing and intelligent resource control for optimal network performance is proposed and implemented. Our experimental results indicate better performance in terms of computation with load balancing and efficient resource alignment for different networking tasks when compared with other competing schemes.Thesis (PhD)--University of Pretoria, 2018.National Research FoundationUniversity of PretoriaElectrical, Electronic and Computer EngineeringPhDUnrestricte

    H.264-based Low Power Heterogeneous Video Recording System

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    ํ•™์œ„๋…ผ๋ฌธ (๋ฐ•์‚ฌ)-- ์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› : ์ „๊ธฐยท์ปดํ“จํ„ฐ๊ณตํ•™๋ถ€, 2015. 2. ๊น€์ˆ˜ํ™˜.์ตœ๊ทผ ์˜์ƒ ์ €์žฅ ์žฅ์น˜์˜ ์‚ฌ์šฉ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ํ•œ์ •๋œ ๋ฐฐํ„ฐ๋ฆฌ์—์„œ ์ €์ „๋ ฅ์œผ๋กœ ์˜์ƒ ์ €์žฅ ์žฅ์น˜๋ฅผ ๋™์ž‘ํ•˜๋Š” ๊ฒƒ์ด ์ค‘์š”ํ•˜๋‹ค. ์˜์ƒ ์ €์žฅ ์žฅ์น˜์—์„œ ์žฅ๊ธฐ ์ €์žฅ์„ ์ˆ˜ํ–‰ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์˜์ƒ ์••์ถ•์ด ํ•„์ˆ˜์ ์ด๋‹ค. ๊ธฐ์กด ์˜์ƒ ์ €์žฅ ์žฅ์น˜์—์„œ ์˜์ƒ ์••์ถ•์„ ์œ„ํ•ด ๋ณดํŽธ์ ์œผ๋กœ ์‚ฌ์šฉ๋˜๋Š” H.264/AVC ์˜์ƒ ์••์ถ• ํ‘œ์ค€์€ ๋†’์€ ์••์ถ•๋ฅ ์„ ์ž๋ž‘ํ•˜์ง€๋งŒ ๋†’์€ ๋ณต์žก๋„์™€ ํ”„๋ ˆ์ž„ ๊ฐ„์˜ ์ธํ„ฐ ํ”„๋ ˆ์ž„ ์˜ˆ์ธก์˜ ์‚ฌ์šฉ์œผ๋กœ ์ „๋ ฅ ์†Œ๋ชจ๊ฐ€ ํฌ๋‹ค๋Š” ๋ฌธ์ œ์ ์„ ๊ฐ–๋Š”๋‹ค. ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ์ด๋Ÿฌํ•œ ๋ฌธ์ œ์ ์„ ํ•ด๊ฒฐํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ๋‘ ๊ฐ€์ง€ ์ ‘๊ทผ ๊ธฐ๋ฒ•์„ ํ†ตํ•ด ์˜์ƒ ์ €์žฅ ์žฅ์น˜์˜ ์†Œ๋ชจ ์ „๋ ฅ ์ค‘, ๊ฐ€์žฅ ํฐ ๋น„์ค‘์„ ์ฐจ์ง€ํ•˜๋Š” ์˜์ƒ ์••์ถ•์— ์†Œ๋ชจ ๋˜๋Š” ์ „๋ ฅ์„ ๊ฐ์†Œ์‹œํ‚จ๋‹ค. ์šฐ์„ , ๋ฉ€ํ‹ฐ ์••์ถ• ๋ชจ๋“ˆ์„ ํ†ตํ•œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜๋ฅผ ํ™œ์šฉํ•œ๋‹ค. Discrete Wavelet Transform๊ณผ Set Partitioning in Hierarchical Trees ์••์ถ•์— ๊ธฐ๋ฐ˜ํ•œ ๊ฒฝ๋Ÿ‰ํ™” ์••์ถ• ๋ฐฉ์‹์€ ์ƒ๋Œ€์ ์œผ๋กœ ๊ฐ„๋‹จํ•œ ์••์ถ• ๋ฐฉ์‹์œผ๋กœ ์••์ถ• ํšจ์œจ์€ H.264/AVC ์ธ์ฝ”๋”์— ๋น„ํ•ด ๋‚ฎ์œผ๋‚˜ ํ›จ์”ฌ ๋” ์ ์€ ์ „๋ ฅ ์†Œ๋ชจ๋กœ ๋™์ž‘ํ•  ์ˆ˜ ์žˆ๋‹ค. ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ๊ธฐ์กด์˜ ์˜์ƒ ์ €์žฅ ์žฅ์น˜์™€ ๋‹ค๋ฅด๊ฒŒ H.264/AVC ์ธ์ฝ”๋”๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ๊ฒฝ๋Ÿ‰ํ™” ์••์ถ• ๋ฐฉ์‹์„ ์˜์ƒ ์ €์žฅ ์žฅ์น˜์— ํ•จ๊ป˜ ํ™œ์šฉํ•˜์—ฌ ์ €์ „๋ ฅ ์˜์ƒ ์ €์žฅ ์žฅ์น˜๋ฅผ ๊ตฌ์„ฑํ•œ๋‹ค. ๋ชจ๋“  ์˜์ƒ ์ •๋ณด๊ฐ€ ์žฅ๊ธฐ ์ €์žฅ ๋˜์–ด ๋ณด๊ด€๋  ํ•„์š”๊ฐ€ ์žˆ๋Š” ๊ฒƒ์ด ์•„๋‹ˆ๊ธฐ ๋•Œ๋ฌธ์— H.264/AVC ์ธ์ฝ”๋”๋ณด๋‹ค ์••์ถ• ํšจ์œจ์€ ๋‹ค์†Œ ๋‚ฎ์ง€๋งŒ ํ›จ์”ฌ ๋‚ฎ์€ ์ „๋ ฅ์—์„œ ๋™์ž‘ํ•  ์ˆ˜ ์žˆ๋Š” ๊ฒฝ๋Ÿ‰ํ™” ์••์ถ• ๋ฐฉ์‹์„ ์ž„์‹œ ์ €์žฅ ์šฉ๋„๋กœ ์‚ฌ์šฉํ•˜๊ณ  ์ด ์˜์ƒ ์ •๋ณด๊ฐ€ ์žฅ๊ธฐ ์ €์žฅ๋  ํ•„์š”๊ฐ€ ์žˆ์„ ๊ฒฝ์šฐ์—๋งŒ ์˜์ƒ ์••์ถ•์„ ์œ„ํ•ด H.264/AVC ์ธ์ฝ”๋”๋ฅผ ์‚ฌ์šฉํ•œ๋‹ค. ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ๊ฒฝ๋Ÿ‰ํ™” ์••์ถ• ๋ฐฉ์‹์˜ ํ™œ์šฉ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ๋‹ค์šด ์ƒ˜ํ”Œ๋ง ๊ธฐ๋ฒ•์„ ์˜์ƒ ์ €์žฅ ์žฅ์น˜์— ํ™œ์šฉํ•˜์—ฌ ๋‚ฎ์€ bitrate ์˜์—ญ์—์„œ ๋”์šฑ ํฐ ์ „๋ ฅ ๊ฐ์†Œ ํšจ๊ณผ๋ฅผ ์–ป๋Š”๋‹ค. ์ด๋Ÿฌํ•œ ๋ฉ€ํ‹ฐ ์••์ถ• ๋ชจ๋“ˆ์„ ํ†ตํ•œ ๋ฐฉ์‹์€ ์žฅ๊ธฐ ์ €์žฅ์˜ ๋น„์œจ์ด ๋†’์•„์ง€๋ฉด ๊ฒฐ๊ตญ H.264/AVC ์ธ์ฝ”๋”๊ฐ€ ์‚ฌ์šฉ๋˜๋Š” ๋น„์œจ์ด ๋†’์•„์ ธ์„œ ์ „๋ ฅ ๊ฐ์†Œ ํšจ๊ณผ๊ฐ€ ํฌ์ง€ ์•Š๋‹ค. ์ด๋Ÿฌํ•œ ์•ฝ์ ์„ ๋ณด์™„ํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” H.264/AVC ์ธ์ฝ”๋” ์ž์ฒด์˜ ์†Œ๋ชจ ์ „๋ ฅ์„ ๊ฐ์†Œ์‹œํ‚ค๋Š” ๊ฒƒ์ด ์ค‘์š”ํ•˜๋‹ค. ๊ทธ๋ ‡๊ธฐ ๋•Œ๋ฌธ์— ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” H.264/AVC ์ธ์ฝ”๋” ๋‚ด๋ถ€์˜ ์ „๋ ฅ ์†Œ๋ชจ๋ฅผ ์ œ์–ดํ•˜๋Š” power-aware design ๊ธฐ๋ฒ•์„ ์˜์ƒ ์ €์žฅ ์žฅ์น˜์— ํ™œ์šฉํ•œ๋‹ค. Power-aware design์€ ์ตœ์†Œ์˜ ์„ฑ๋Šฅ ์ €ํ•˜๋กœ ์ตœ๋Œ€์˜ ์ „๋ ฅ ๊ฐ์†Œ ํšจ๊ณผ๋ฅผ ์–ป๋Š” ๊ธฐ๋ฒ•์œผ๋กœ ๋‹ค์–‘ํ•œ ์ €์ „๋ ฅ ์•Œ๊ณ ๋ฆฌ์ฆ˜์˜ ๋™์ž‘ ์˜ต์…˜๋“ค์˜ ์กฐํ•ฉ๋“ค ์ค‘์—์„œ ์ตœ์ ํ™”๋œ ์•Œ๊ณ ๋ฆฌ์ฆ˜์˜ ์กฐํ•ฉ๋“ค๋กœ power-level table์„ ์ •์˜ํ•˜๊ณ  ์ด๋ฅผ ์ธ์ฝ”๋”์— ์ ์šฉํ•œ๋‹ค. ์ตœ์ ํ™”๋œ ์กฐํ•ฉ์„ ์ฐพ๊ธฐ ์œ„ํ•˜์—ฌ ์•Œ๊ณ ๋ฆฌ์ฆ˜๋“ค ๊ฐ„์˜ ์ƒ๊ด€ ๊ด€๊ณ„๋ฅผ ๊ณ ๋ คํ•˜์—ฌ ๊ฐœ๋ณ„ ์•Œ๊ณ ๋ฆฌ์ฆ˜์˜ ์ „๋ ฅ ๊ฐ์†Œ ํšจ๊ณผ๋ฅผ ํ†ตํ•ด ์ „์ฒด ์‹œ์Šคํ…œ์˜ ์ „๋ ฅ ๊ฐ์†Œ ํšจ๊ณผ๋ฅผ ์˜ˆ์ธกํ•˜๋Š” ๋ชจ๋ธ์„ ํ™œ์šฉํ•˜๋Š”๋ฐ ์ด๋Ÿฌํ•œ ์ „๋ ฅ ์˜ˆ์ธก ๋ชจ๋ธ์„ ์‚ฌ์šฉํ•˜๋ฉด ์ตœ์ ํ™”๋œ ์•Œ๊ณ ๋ฆฌ์ฆ˜๋“ค์˜ ์กฐํ•ฉ์„ ์ฐพ๊ธฐ ์œ„ํ•œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ํšŸ์ˆ˜๊ฐ€ ํ˜„์ €ํ•˜๊ฒŒ ๊ฐ์†Œ๋˜๊ธฐ ๋•Œ๋ฌธ์— ์—ฌ๋Ÿฌ ์ €์ „๋ ฅ ์•Œ๊ณ ๋ฆฌ์ฆ˜์ด ํ•จ๊ป˜ ์‚ฌ์šฉ๋˜๋”๋ผ๋„ ์ตœ์ ์˜ ์กฐํ•ฉ์„ ์‰ฝ๊ฒŒ ๊ตฌ์„ฑํ•  ์ˆ˜ ์žˆ๋‹ค. ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ๋” ๋›ฐ์–ด๋‚œ ์„ฑ๋Šฅ์„ ์–ป๊ธฐ ์œ„ํ•ด์„œ ์ž…๋ ฅ ์˜์ƒ์˜ ํฌ๊ธฐ์™€ ์›€์ง์ž„ ์—ฌ๋ถ€์— ๋”ฐ๋ผ์„œ ๋„ค ๊ฐ€์ง€์˜ ๋‹ค๋ฅธ power-level table์„ ์ œ์‹œํ•˜๋ฉฐ ์ด๋Ÿฌํ•œ power-level table์ด ์‚ฌ์ „์— ์ •์˜๋˜๊ธฐ ๋•Œ๋ฌธ์— ์ตœ์ ํ™”๋œ ์ €์ „๋ ฅ ์•Œ๊ณ ๋ฆฌ์ฆ˜์˜ ์กฐํ•ฉ๋“ค์ด ์‹ค์‹œ๊ฐ„์œผ๋กœ ์ธ์ฝ”๋”์— ์ ์šฉ๋  ์ˆ˜ ์žˆ๋‹ค. ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ์˜์ƒ ์ €์žฅ ์žฅ์น˜์˜ ์ „๋ ฅ ๊ฐ์†Œ๋ฅผ ์œ„ํ•ด ์ œ์‹œ๋œ ๋ฉ€ํ‹ฐ ์••์ถ• ๋ชจ๋“ˆ์„ ํ™œ์šฉํ•˜๋Š” ๋ฐฉ์‹๊ณผ H.264/AVC ์ธ์ฝ”๋” ๋‚ด๋ถ€์˜ ์ „๋ ฅ ์†Œ๋ชจ๋ฅผ ๊ฐ์†Œํ•˜๋Š” ๋ฐฉ์‹์„ ๋ชจ๋‘ ์ง€์›ํ•˜๋Š” ํ†ตํ•ฉ ์˜์ƒ ์ €์žฅ ์žฅ์น˜๋ฅผ ๊ตฌํ˜„ํ•˜๊ณ  ํ†ตํ•ฉ๋œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜ ์ƒ์—์„œ ์žฅ๊ธฐ ์ €์žฅ์˜ ๋น„์œจ๊ณผ bitrate ๋ชฉํ‘œ์— ๋”ฐ๋ฅธ ๋ถ„์„์„ ํ†ตํ•˜์—ฌ ๋™์ž‘ ์ƒํ™ฉ์— ๊ฐ€์žฅ ์•Œ๋งž์€ ์ตœ์ ํ™”๋œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜๋ฅผ ํ™œ์šฉํ•œ๋‹ค. ์ด๋Ÿฌํ•œ ์ตœ์ ํ™”๋œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜๋Š” ์ตœ์†Œํ•œ์˜ ์„ฑ๋Šฅ ์ €ํ•˜๋กœ ๊ธฐ์กด์˜ ์˜์ƒ ์ €์žฅ ์žฅ์น˜ ๋Œ€๋น„ ์ตœ๋Œ€ 72.5%์˜ ์ „๋ ฅ ๊ฐ์†Œ ํšจ๊ณผ๋ฅผ ๊ฐ–๋Š”๋‹ค.์ดˆ ๋ก i ๋ชฉ ์ฐจ iv ๊ทธ๋ฆผ ๋ชฉ์ฐจ viii ํ‘œ ๋ชฉ ์ฐจ xi ์ œ 1 ์žฅ ์„œ ๋ก  1 1.1 ์—ฐ๊ตฌ ๋ฐฐ๊ฒฝ 1 1.2 ์—ฐ๊ตฌ ๋‚ด์šฉ 3 1.3 ๋…ผ๋ฌธ ๊ตฌ์„ฑ 7 ์ œ 2 ์žฅ ๊ด€๋ จ ์—ฐ๊ตฌ 8 2.1 ์˜์ƒ ์ €์žฅ ์žฅ์น˜์˜ ๋™์ž‘ 8 2.2 H.264/AVC ์˜์ƒ ์••์ถ• ํ‘œ์ค€ 12 2.2.1 H.264/AVC ์ธ์ฝ”๋”์˜ ๋™์ž‘ 12 2.2.2 ์ €์ „๋ ฅ H.264/AVC ์ธ์ฝ”๋”๋ฅผ ์œ„ํ•œ ๊ธฐ์กด ์—ฐ๊ตฌ 15 2.3 ๊ฒฝ๋Ÿ‰ํ™” ์••์ถ• ๋ฐฉ์‹ ์•Œ๊ณ ๋ฆฌ์ฆ˜ 19 2.3.1 1์ฐจ์› Discrete Wave Transform 19 2.3.2 Set Partitioning in Hierarchical Trees 20 2.3.3 1์ฐจ์› ๊ฒฝ๋Ÿ‰ํ™” ์••์ถ• ๋ฐฉ์‹ ๊ธฐ๋ฒ• 21 ์ œ 3 ์žฅ ๋ฉ€ํ‹ฐ ์••์ถ• ๋ชจ๋“ˆ์„ ํ†ตํ•œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜ 22 3.1 ๊ฒฝ๋Ÿ‰ํ™” ์••์ถ• ๋ฐฉ์‹์˜ ๊ตฌํ˜„ 22 3.1.1 ๊ตฌํ˜„ ๋ฐฉ์‹ 22 3.1.2 ๊ตฌํ˜„ ๊ฒฐ๊ณผ ๋ฐ ์„ฑ๋Šฅ ๋น„๊ต 28 3.2 ๊ฒฝ๋Ÿ‰ํ™” ์••์ถ• ๋ฐฉ์‹์„ ํ†ตํ•œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜์˜ ๊ตฌํ˜„ 34 3.2.1 LWC ๊ธฐ๋ฐ˜ ์˜์ƒ ์ €์žฅ ์žฅ์น˜ 35 3.2.2 D-LPFC ๊ธฐ๋ฐ˜ ์˜์ƒ ์ €์žฅ ์žฅ์น˜ 38 3.2.3 ์ œ์•ˆ๋œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜์˜ ๋ถ„์„ 42 3.3 ์„ฑ๋Šฅ ํ‰๊ฐ€ 45 3.3.1 ์ „๋ ฅ ์ธก์ • ๋ฐฉ๋ฒ• 45 3.3.2 ๋ชจ๋“œ ๋ณ„ ์ „๋ ฅ ๋ถ„์„ 48 3.3.3 FRECORD์— ๋”ฐ๋ฅธ ์‹œ์Šคํ…œ ์ „์ฒด ์ „๋ ฅ ๋ฐ ์„ฑ๋Šฅ ๋ถ„์„ 52 ์ œ 4 ์žฅ H.264/AVC ์ž์ฒด์ ์ธ ์ „๋ ฅ ๊ฐ์†Œ ๊ธฐ๋ฒ• 55 4.1 H.264/AVC ์ž์ฒด ์ „๋ ฅ ๊ฐ์†Œ์˜ ํ•„์š”์„ฑ 55 4.2 Power-Aware Design 56 4.2.1 Power Level Table์˜ ์ƒ์„ฑ 56 4.2.2 ์ž…๋ ฅ ์˜์ƒ์˜ ํŠน์ง•์ด ๋ฏธ์น˜๋Š” ์˜ํ–ฅ 59 4.2.3 ์ „๋ ฅ ๋ ˆ๋ฒจ์˜ ์œ ๋™์  ์„ ํƒ ๊ธฐ๋ฒ• 60 4.2.4 ์ „๋ ฅ ๋ ˆ๋ฒจ ์ ์šฉ ์•Œ๊ณ ๋ฆฌ์ฆ˜ 62 4.3 ์ „๋ ฅ ์˜ˆ์ธก ๋ชจ๋ธ 65 4.4 Power-Aware Design์˜ ์˜ˆ์‹œ 71 4.4.1 ๋„ค ๊ฐ€์ง€ ์ €์ „๋ ฅ ์•Œ๊ณ ๋ฆฌ์ฆ˜ 71 4.4.2 ์ „๋ ฅ ์˜ˆ์ธก ๋ชจ๋ธ์˜ ์˜ˆ์‹œ 73 4.4.3 ๊ฐœ๋ณ„ ์•Œ๊ณ ๋ฆฌ์ฆ˜์˜ ์ „๋ ฅ ์†Œ๋ชจ ์ธก์ • 76 4.4.4 ์ตœ์ ํ™”๋œ ์•Œ๊ณ ๋ฆฌ์ฆ˜ ์˜ต์…˜์˜ ์„ ํƒ 84 4.4.5 Power level table์˜ ์ƒ์„ฑ์˜ ์˜ˆ์‹œ 87 4.5 ์„ฑ๋Šฅ ํ‰๊ฐ€ 92 4.5.1 Power-Aware Design์˜ ์„ฑ๋Šฅ ์ธก์ • 92 4.5.2 ๊ธฐ์กด Power-Aware Design๊ณผ์˜ ์„ฑ๋Šฅ ๋น„๊ต 105 4.5.3 Power-Aware Design์˜ ์˜์ƒ ์ €์žฅ ์žฅ์น˜ ์ ์šฉ 113 ์ œ 5 ์žฅ ์ตœ์ ํ™”๋œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜์˜ ํ™œ์šฉ ๊ธฐ๋ฒ• 115 5.1 ํ†ตํ•ฉ ์˜์ƒ ์ €์žฅ ์žฅ์น˜ 116 5.1.1 ํ†ตํ•ฉ ์˜์ƒ ์ €์žฅ ์žฅ์น˜์˜ ๊ตฌํ˜„ 116 5.1.2 ํ†ตํ•ฉ ์˜์ƒ ์ €์žฅ ์žฅ์น˜์˜ FPGA ๊ฒ€์ฆ 119 5.2 ์ตœ์ ํ™”๋œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜ 122 5.2.1 ์ตœ์ ํ™”๋œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜๋ฅผ ์œ„ํ•œ ๋ถ„์„ 122 5.2.2 ์ตœ์ ํ™”๋œ ์˜์ƒ ์ €์žฅ ์žฅ์น˜ ์„ ํƒ ๊ธฐ๋ฒ• 130 5.3 ์„ฑ๋Šฅ ํ‰๊ฐ€ 132 ์ œ 6 ์žฅ ๊ฒฐ๋ก  137 ์ฐธ๊ณ ๋ฌธํ—Œ 139 Abstract 144Docto

    A cross-layer approach for optimizing the efficiency of wireless sensor and actor networks

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    Recent development has lead to the emergence of distributed Wireless Sensor and Actor Networks (WSAN), which are capable of observing the physical environment, processing the data, making decisions based on the observations and performing appropriate actions. WSANs represent an important extension of Wireless Sensor Networks (WSNs) and may comprise a large number of sensor nodes and a smaller number of actor nodes. The sensor nodes are low-cost, low energy, battery powered devices with restricted sensing, computational and wireless communication capabilities. Actor nodes are resource richer with superior processing capabilities, higher transmission powers and a longer battery life. A basic operational scenario of a typical WSAN application follows the following sequence of events. The physical environment is periodically sensed and evaluated by the sensor nodes. The sensed data is then routed towards an actor node. Upon receiving sensed data, an actor node performs an action upon the physical environment if necessary, i.e. if the occurrence of a disturbance or critical event has been detected. The specific characteristics of sensor and actor nodes combined with some stringent application constraints impose unique requirements for WSANs. The fundamental challenges for WSANs are to achieve low latency, high energy efficiency and high reliability. The latency and energy efficiency requirements are in a trade-off relationship. The communication and coordination inside WSANs is managed via a Communication Protocol Stack (CPS) situated on every node. The requirements of low latency and energy efficiency have to be addressed at every layer of the CPS to ensure overall feasibility of the WSAN. Therefore, careful design of protocol layers in the CPS is crucial in attempting to meet the unique requirements and handle the abovementioned trade-off relationship in WSANs. The traditional CPS, comprising the application, network, medium access control and physical layer, is a layered protocol stack with every layer, a predefined functional entity. However, it has been found that for similar types of networks with similar stringent network requirements, the strictly layered protocol stack approach performs at a sub-optimal level with regards to network efficiency. A modern cross-layer paradigm, which proposes the employment of interactions between layers in the CPS, has recently attracted a lot of attention. The cross-layer approach promotes network efficiency optimization and promises considerable performance gains. It is found that in literature, the adoption of this cross-layer paradigm has not yet been considered for WSANs. In this dissertation, a complete cross-layer enabled WSAN CPS is developed that features the adoption of the cross-layer paradigm towards promoting optimization of the network efficiency. The newly proposed cross-layer enabled CPS entails protocols that incorporate information from other layers into their local decisions. Every protocol layer provides information identified as beneficial to another layer(s) in the CPS via a newly proposed Simple Cross-Layer Framework (SCLF) for WSANs. The proposed complete cross-layer enabled WSAN CPS comprises a Cross-Layer enabled Network-Centric Actuation Control with Data Prioritization (CL-NCAC-DP) application layer (APPL) protocol, a Cross-Layer enabled Cluster-based Hierarchical Energy/Latency-Aware Geographic Routing (CL-CHELAGR) network layer (NETL) protocol and a Cross-Layer enabled Carrier Sense Multiple Access with Minimum Preamble Sampling and Duty Cycle Doubling (CL-CSMA-MPS-DCD) medium access control layer (MACL) protocol. Each of these protocols builds on an existing simple layered protocol that was chosen as a basis for development of the cross-layer enabled protocols. It was found that existing protocols focus primarily on energy efficiency to ensure maximum network lifetime. However, most WSAN applications require latency minimization to be considered with the same importance. The cross-layer paradigm provides means of facilitating the optimization of both latency and energy efficiency. Specifically, a solution to the latency versus energy trade-off is given in this dissertation. The data generated by sensor nodes is prioritised by the APPL and depending on the delay-sensitivity, handled in a specialised manor by every layer of the CPS. Delay-sensitive data packets are handled in order to achieve minimum latency. On the other hand, delay-insensitive non critical data packets are handled in such a way as to achieve the highest energy efficiency. In effect, either latency minimization or energy efficiency receives an elevated precedence according to the type of data that is to be handled. Specifically, the cross-layer enabled APPL protocol provides information pertaining to the delay-sensitivity of sensed data packets to the other layers. Consequently, when a data packet is detected as highly delay-sensitive, the cross-layer enabled NETL protocol changes its approach from energy efficient routing along the maximum residual energy path to routing along the fastest path towards the cluster-head actor node for latency minimizing of the specific packet. This is done by considering information (contained in the SCLF neighbourhood table) from the MACL that entails wakeup schedules and channel utilization at neighbour nodes. Among the added criteria, the next-hop node is primarily chosen based on the shortest time to wakeup. The cross-layer enabled MACL in turn employs a priority queue and a temporary duty cycle doubling feature to enable rapid relaying of delay-sensitive data. Duty cycle doubling is employed whenever a sensor nodeโ€™s APPL state indicates that it is part of a critical event reporting route. When the APPL protocol state (found in the SCLF information pool) indicates that the node is not part of the critical event reporting route anymore, the MACL reverts back to promoting energy efficiency by disengaging duty cycle doubling and re-employing a combination of a very low duty cycle and preamble sampling. The APPL protocol conversely considers the current queue size of the MACL and temporarily halts the creation of data packets (only if the sensed value is non critical) to prevent a queue overflow and ease congestion at the MACL By simulation it was shown that the cross-layer enabled WSAN CPS consistently outperforms the layered CPS for various network conditions. The average end-to-end latency of delay-sensitive critical data packets is decreased substantially. Furthermore, the average end-to-end latency of delay-insensitive data packets is also decreased. Finally, the energy efficiency performance is decreased by a tolerable insignificant minor margin as expected. The trivial increase in energy consumption is overshadowed by the high margin of increase in latency performance for delay-sensitive critical data packets. The newly proposed cross-layer CPS achieves an immense latency performance increase for WSANs, while maintaining excellent energy efficiency. It has hence been shown that the adoption of the cross-layer paradigm by the WSAN CPS proves hugely beneficial with regards to the network efficiency performance. This increases the feasibility of WSANs and promotes its application in more areas.Dissertation (MEng)--University of Pretoria, 2009.Electrical, Electronic and Computer Engineeringunrestricte

    Dynamic Resource Management of Network-on-Chip Platforms for Multi-stream Video Processing

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    This thesis considers resource management in the context of parallel multiple video stream decoding, on multicore/many-core platforms. Such platforms have tens or hundreds of on-chip processing elements which are connected via a Network-on-Chip (NoC). Inefficient task allocation configurations can negatively affect the communication cost and resource contention in the platform, leading to predictability and performance issues. Efficient resource management for large-scale complex workloads is considered a challenging research problem; especially when applications such as video streaming and decoding have dynamic and unpredictable workload characteristics. For these type of applications, runtime heuristic-based task mapping techniques are required. As the application and platform size increase, decentralised resource management techniques are more desirable to overcome the reliability and performance bottlenecks in centralised management. In this work, several heuristic-based runtime resource management techniques, targeting real-time video decoding workloads are proposed. Firstly, two admission control approaches are proposed; one fully deterministic and highly predictable; the other is heuristic-based, which balances predictability and performance. Secondly, a pair of runtime task mapping schemes are presented, which make use of limited known application properties, communication cost and blocking-aware heuristics. Combined with the proposed deterministic admission controller, these techniques can provide strict timing guarantees for hard real-time streams whilst improving resource usage. The third contribution in this thesis is a distributed, bio-inspired, low-overhead, task re-allocation technique, which is used to further improve the timeliness and workload distribution of admitted soft real-time streams. Finally, this thesis explores parallelisation and resource management issues, surrounding soft real-time video streams that have been encoded using complex encoding tools and modern codecs such as High Efficiency Video Coding (HEVC). Properties of real streams and decoding trace data are analysed, to statistically model and generate synthetic HEVC video decoding workloads. These workloads are shown to have complex and varying task dependency structures and resource requirements. To address these challenges, two novel runtime task clustering and mapping techniques for Tile-parallel HEVC decoding are proposed. These strategies consider the workload communication to computation ratio and stream-specific characteristics to balance predictability improvement and communication energy reduction. Lastly, several task to memory controller port assignment schemes are explored to alleviate performance bottlenecks, resulting from memory traffic contention

    D6.6 Final report on the METIS 5G system concept and technology roadmap

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    This deliverable presents the METIS 5G system concept which was developed to fulfil the requirements of the beyond-2020 connected information society and to extend todayโ€™s wireless communication systems to include new usage scenarios. The METIS 5G system concept consists of three generic 5G services and four main enablers. The three generic 5G services are Extreme Mobile BroadBand (xMBB), Massive Machine- Type Communications (mMTC), and Ultra-reliable Machine-Type Communication (uMTC). The four main enablers are Lean System Control Plane (LSCP), Dynamic RAN, Localized Contents and Traffic Flows, and Spectrum Toolbox. An overview of the METIS 5G architecture is given, as well as spectrum requirements and considerations. System-level evaluation of the METIS 5G system concept has been conducted, and we conclude that the METIS technical objectives are met. A technology roadmap outlining further 5G development, including a timeline and recommended future work is given.Popovski, P.; Mange, G.; Gozalvez -Serrano, D.; Rosowski, T.; Zimmermann, G.; Agyapong, P.; Fallgren, M.... (2014). D6.6 Final report on the METIS 5G system concept and technology roadmap. http://hdl.handle.net/10251/7676

    State-of-the-Art Sensors Technology in Spain 2015: Volume 1

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    This book provides a comprehensive overview of state-of-the-art sensors technology in specific leading areas. Industrial researchers, engineers and professionals can find information on the most advanced technologies and developments, together with data processing. Further research covers specific devices and technologies that capture and distribute data to be processed by applying dedicated techniques or procedures, which is where sensors play the most important role. The book provides insights and solutions for different problems covering a broad spectrum of possibilities, thanks to a set of applications and solutions based on sensory technologies. Topics include: โ€ข Signal analysis for spectral power โ€ข 3D precise measurements โ€ข Electromagnetic propagation โ€ข Drugs detection โ€ข e-health environments based on social sensor networks โ€ข Robots in wireless environments, navigation, teleoperation, object grasping, demining โ€ข Wireless sensor networks โ€ข Industrial IoT โ€ข Insights in smart cities โ€ข Voice recognition โ€ข FPGA interfaces โ€ข Flight mill device for measurements on insects โ€ข Optical systems: UV, LEDs, lasers, fiber optics โ€ข Machine vision โ€ข Power dissipation โ€ข Liquid level in fuel tanks โ€ข Parabolic solar tracker โ€ข Force sensors โ€ข Control for a twin roto

    The Next Generation Intelligent Transportation System: Connected, Safe and Green

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    Modern Intelligent Transportation Systems (ITSs) employ communication technologies in order to ameliorate the passenger's commuting experience. Vehicular Networking lies at the core of inaugurating an efficient transportation system and aims at transforming vehicles into smart mobile entities that are able to sense their surroundings, collect information about the environment and communicate with each other as well as with Roadside Units (RSUs) deployed alongside roadways. As such, the novel communication paradigm of vehicular networking gave birth to an ITS that embraces a wide variety of applications including but not limited to: traffic management, passenger and road safety, environment monitoring and road surveillance, hot-spot guidance, Drive Thru Internet access, remote region connectivity, and so forth. Furthermore, with the rapid development of computation and communication technologies, the Internet of Vehicles (IoV) promises huge commercial interest and research value, thereby attracting a significant industrial and academic attention. This thesis studies and analyses fundamentally challenging problems in the context of vehicular environments and proposes new techniques targeting the improvement of the performance of ITSs envisioned to play a remarkable role in the IoV era. Unlike existing wireless mobile networks, vehicular networks possess unique characteristics, including high node mobility and a rapidly-changing topology, which should be carefully accounted for. Four major problems from the pool of existing vehicular networking persisting challenges will be addressed in this thesis, namely: a) establishing a connectivity path in a highly dynamic Vehicular Ad Hoc Network, b) examining the performance of Vehicle-to-Infrastructure communication Medium Access Control schemes, c) addressing the scheduling problem of a vehicular networking scenario encompassing an energy-limited RSU by exploiting machine learning techniques, particularly reinforcement learning, to train an agent to make appropriate decisions and develop a scheduling policy that prolongs the network's operational status and allows for acceptable Quality-of-Service levels and d) overcoming the limitations of reinforcement learning techniques in high-dimensional input scenarios by exploiting recent advances in deep learning in an effort to satisfy the driver's well-being as well as his demand for continuous connectivity in a green, balanced, connected and efficient vehicular network. These problems will be extensively studied throughout this thesis, followed by discussions that highlight open research directions worth further investigations
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