Journal Papers by Mehmet Yunus Dönmez
In a typical wireless sensor network, the batteries of the nodes near the sink deplete quicker th... more In a typical wireless sensor network, the batteries of the nodes near the sink deplete quicker than other nodes due to the data traffic concentrating towards the sink, leaving it stranded and disrupting the sensor data reporting. To mitigate this problem, mobile sinks are proposed. They implicitly provide load-balanced data delivery and achieve uniform-energy consumption across the network. On the other hand, advertising the position of the mobile sink to the network introduces an overhead in terms of energy consumption and packet delays. In this paper, we propose Ring Routing, a novel, distributed, energy-efficient mobile sink routing protocol, suitable for time-sensitive applications, which aims to minimize this overhead while preserving the advantages of mobile sinks. Furthermore, we evaluate the performance of Ring Routing via extensive simulations.
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Congestion is a challenging problem for sensor networks because it causes the waste of communicat... more Congestion is a challenging problem for sensor networks because it causes the waste of communication and reduces energy efficiency. Compared to traditional wireless sensor networks, the probability of congestion occurrence in wireless multimedia sensor networks is higher due to the high volume of data arising from multimedia streaming. In this article, problems for multimedia transmission over wireless multimedia sensor networks are examined and sensor fuzzy-based image transmission (SUIT); a new progressive image transport protocol is proposed as a solution. SUIT provides fuzzy logic-based congestion estimation and an efficient congestion mitigation technique which decreases the image quality on-the-fly to an acceptable level. In case of congestion, SUIT drops some packets of the frames in a smart way and thus transmits frames to the sink with lower, but acceptable quality. In this way, SUIT improves the continuity of the video streaming. We evaluate the performance of SUIT by comparing it with two different competitors. The first one is an example transport protocol, namely Fuzzy Logic-Based Congestion Estimation. The second one is a buffer occupancy-based congestion control mechanism which is commonly used in previous studies. According to the simulation results, SUIT provides better energy consumption, frame delivery, frame loss and frame latency performance than its competitors.
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Emerging multimedia applications for sensor networks require the co-existence of different types ... more Emerging multimedia applications for sensor networks require the co-existence of different types of traffic with different QoS provisions in terms of latency and throughput. Prioritization-based service differentiation mechanisms are applied in all layers of communication to satisfy the QoS requirements of each traffic class. The prioritization in the contention is one of these differentiation methods applied in the medium access layer. In this article, we propose an analytical model for the contention latencies and energy expenditures of different classes in a prioritized contention structure with uniform backoff scheme. The contention window is divided into three partitions which are allocated for the use of only high-priority, both priorities, and only low-priority classes. We further generalize the model for binary exponential backoff schemes and for more than two priority classes. In the analysis, we explore the optimum sizes of these partitions in terms of contention latency and the total energy expenditure for each priority class. Our model is also useful for the evaluation of various recent contention prioritization schemes in WSNs.
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The concentration of data traffic towards the sink in a wireless sensor network causes the nearby... more The concentration of data traffic towards the sink in a wireless sensor network causes the nearby nodes to deplete their batteries quicker than other nodes, which leaves the sink stranded and disrupts the sensor data reporting. To mitigate this problem the usage of mobile sinks is proposed. Mobile sinks implicitly provide load-balancing and help achieving uniform energy-consumption across the network. However, the mechanisms to support the sink mobility (e.g., advertising the location of the mobile sink to the network) introduce an overhead in terms of energy consumption and packet delays. With these properties mobile sink routing constitutes an interesting research field with unique requirements. In this paper, we present a survey of the existing distributed mobile sink routing protocols. In order to provide an insight to the rationale and the concerns of a mobile sink routing protocol, design requirements and challenges associated with the problem of mobile sink routing are determined and explained. A definitive and detailed categorization is made and the protocols' advantages and drawbacks are determined with respect to their target applications.
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The main objective in a wireless sensor network design is to minimize the energy expenditure for ... more The main objective in a wireless sensor network design is to minimize the energy expenditure for sustaining a long lifetime. Moreover, some recent multimedia applications require the network to satisfy specific throughput and delay constraints for large data sizes. In this paper, we analytically derive the expected throughput and the expected energy expenditure for a synchronized contention-based duty cycled MAC protocol. Our analysis explores the combined effect of contention window size, duty cycle and data size on throughput and energy expenditure for a successful transmission. We show that the performance of the network in terms of both metrics fluctuates with increased duty cycle as opposed to the general intuition that an increase in duty cycle increases the throughput and decreases the energy expenditure in the network. The results, validated by simulations, show that in order to provide an efficient MAC operation, the contention window size and the duty cycle should be optimized together for a given data size.
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Computer Communications, 2012
The performance of a surveillance wireless sensor network is generally measured with its detectio... more The performance of a surveillance wireless sensor network is generally measured with its detection capability within a monitored zone. This capability is affected by various parameters such as the sensor count, the sensor range, the area width and the target mobility model. In real life examples it is observed that intruders prefer some favorite regions because of their geographical advantages within a monitored border area. These regions, which bounds the randomly chosen trespassing paths, are generally in close vicinity. In this paper, we introduce the notion of trespassers’ favorite paths (TFP) and provide a tool that can be used to forecast the detection probability of a surveillance network in such a network with TFPs. The detection probability is reduced to the geometric line intersection problem using bijection and the boundary conditions of intruder trajectories for the border area and the favorite region are determined. The line intersection problem is solved using tools from the integral geometry and geometric probability. The effect of the favorable region on the detection quality under different conditions is calculated using probabilistic models. The accuracy of the proposed quality metric is validated by both analytical methods and simulation results. Furthermore, the importance of the intrusion model on the network performance is presented using realistic scenarios. It is shown that the existence of favorite paths has significant impact on the detection quality of the network. The proposed detection quality metric provides analytical tools suitable for both real life and simulation scenarios to the network designers to forecast and optimize the expected detection performance, and is computationally inexpensive compared to both simulation based and distributed quality measurements.
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Computer Networks, Jan 1, 2012
Congestion is a challenging problem in wireless sensor networks, which exacerbates with the high ... more Congestion is a challenging problem in wireless sensor networks, which exacerbates with the high volume of data traffic imposed by video applications such as video surveillance and target tracking. Deployment of multiple sinks is a candidate solution for congestion and is also promising in terms of reliability and energy-efficiency. In order to gain the maximum benefit from multiple sinks, it is essential to distribute the load among them evenly. In this paper, we propose a cross layer geographic forwarding scheme MLBRF (Multi-SinkLoadBalanced Reliable Forwarding) which aims to provide reliable and energy efficient video delivery in a multi-sinked sensor network for target tracking. In order to provide load balancing among the sinks, MLBRF proposes a sink selection mechanism based on fuzzy logic for the frame forwarding which evaluates the traffic density in the direction of each sink by combining two dynamic criteria which are the number of contenders and the buffer occupancy levels in the neighborhood with the static distance criterion. The performance of the fuzzy sink selection mechanism is compared using simulation with various sink selection mechanisms. The results show that MLBRF gains the maximum benefit from deploying multiple sinks in terms of reliability, latency and energy efficiency by using the proposed fuzzy sink selection mechanism.
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In this paper, we propose two cross layer geographic forwarding schemes which address congestion ... more In this paper, we propose two cross layer geographic forwarding schemes which address congestion in wireless video sensor networks (VSN) to provide reliable video delivery. The first scheme Load Balanced Reliable Forwarding (LBRF) introduces the notion of local load balancing where a sensor dynamically determines the next hop among the alternative neighbors providing positive advancement towards the sink by considering the balance of their buffer occupancy levels at the time of delivery. LBRF utilizes a modified version of SMAC where the packet structure as well as the operation of SMAC is modified for the accurate monitoring of the buffer occupancy conditions of the neighbors. The second scheme Directional Load Balanced Spreading (DLBS) combines local and direction-based (spatial) load balancing approaches to provide more reliable and faster video delivery by benefiting from the advantages of both approaches. The performance of the forwarding schemes are compared using simulation with two geographic routing schemes where one applies no load balancing and the other applies spatial load balancing. The results show that both LBRF and DLBS provide more reliable video delivery as compared to other schemes, whereas DLBS is more reliable and faster as compared to LBRF. In addition, DLBS provides more energy efficient video delivery in terms of energy expenditure per successfully delivered frame to the sink as compared to LBRF and the other two schemes.
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The requirements of surveillance wireless sensor networks, such as latency and reliability provis... more The requirements of surveillance wireless sensor networks, such as latency and reliability provisions, are directly related to the deployment quality, which is an indicator of the sensing capability of the network. The determination of the deployment quality is hindered by various factors that cause coverage holes, such as the existence of jammers and destruction of sensors. This paper presents an analytical deployment quality measure in terms of network parameters, including the sensor count, sensing coverage, coverage hole count, coverage hole area size and deployment area size. Assuming a random deployment model for both sensors and holes, our method determines the probability of detection of a target following a linear trajectory by a single sensor and generalizes it to derive the probability of detection in a network with coverage holes. The overall probability of detection is used as the network quality measure and is proposed as a suitable metric under sensor loss assumptions. The proposed deployment quality metric (DQM) is based on the shortest path strategy to provide a conservative estimation for the intruder detection performance. We show that it provides a good estimation of the actual deployment quality with given coverage hole and jamming area properties. Our metric is suitable for real life and simulation scenarios and is computationally inexpensive compared to both simulation based and distributed quality measurements.
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Wireless Information Delivery Environment (WIDE) is a distributed data dissemination system, whic... more Wireless Information Delivery Environment (WIDE) is a distributed data dissemination system, which uses IEEE 802.11b technology. WIDE aims to deliver popular information services to registered mobile clients in WLAN hot spots. Data delivery is based on broadcasting and multicasting to provide scalability and efficient use of the wireless channel. Reliability is assured with a combination of Forward Error Correction (FEC), data carousel, and ARQ techniques. This paper presents the proposed system architecture with the details of reliable and secure data dissemination mechanisms. Functional evaluation of the proposed system and mechanisms on the implemented prototype are also included in this paper.
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We developed an information delivery system, namely WIDE (Wireless Information Delivery Environme... more We developed an information delivery system, namely WIDE (Wireless Information Delivery Environment), on client-server architecture using IEEE 802.11b infrastructure. WIDE aims to deliver popular information services to registered mobile clients in WLAN (Wireless Information Local Area Network) hot spots. We present the proposed system architecture, related delivery mechanism and communication protocols. We also give a brief overview of the mechanisms required for secure and reliable communication over a WIDE system.
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Conference Papers by Mehmet Yunus Dönmez
Mobile sinks are proposed as a possible solution
to the hotspot problem, which leads to the earl... more Mobile sinks are proposed as a possible solution
to the hotspot problem, which leads to the early death of the
nodes close to the sink, due to the concentration of data traffic
towards the sinks. However, the route updates employed by the
source nodes to determine the position of the sinks introduce an
overhead in terms of data reporting delays and energy consumptions.
On the other hand, decreased frequency of route updates
causes stale sink position information to be utilized for data
packets which results in suboptimal data dissemination paths.
In this paper, we investigate this inherent trade-off and provide
an insight on how to fine tune the route update parameters of a
mobile sink routing protocol. For this purpose, we define a system
employing a simple routing protocol and determine the optimal
operating points from the results obtained via simulations, under
varying degrees of route updates and sink mobility.
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Forest fires lead to high amount of environmental and economic loss all over the world. Preventio... more Forest fires lead to high amount of environmental and economic loss all over the world. Prevention and early detection efforts aim to eliminate or minimize the damage that will be caused by a fire incident. Current surveillance systems for forest fires do not provide dense real-time monitoring and hence they lack prevention or early detection of a fire threat. Wireless sensor networks (WSNs), on the other hand, can collect real-time information such as temperature and humidity from almost all points of a forest and can provide fresh and accurate data for the fire-fighting management center quickly. In this work, we aim to evaluate the reporting performance of a WSN under realistic workload. Since fires are destructive and burning a deployed WSN is not feasible, simulation is the appropriate way to assess the reporting capability of a WSN during a forest fire. We integrate WSN simulator with a realistic fire propagation simulator which is modified to provide time based temperature field information while the fire propagates through the deployment area. Temperature information is used for the generation of realistic workloads and the determination of sensor destruction times that affects the routing decisions in WSN simulations. We present the effects of WSN related factors; such as reporting rate, number of the sinks, and the sink locations together with the effects of environmental factors such as the wind speed and the number of ignition points in terms of temperature reporting performance and freshness of temperature map.
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(Türkçe)
Orman yangınları doğal yaşamı ve insan yaşamını tehdit eden önemli bir felakettir. Doğa... more (Türkçe)
Orman yangınları doğal yaşamı ve insan yaşamını tehdit eden önemli bir felakettir. Doğaya, ekonomiye ve tarihsel kültüre verdikleri tahribat, orman yangınlarının erken tespit edilip büyümelerinin önlenmesini önemli kılmaktadır. Bir yangın tespit sisteminin başarısını, yangını en kısa zamanda ve hatasız tespit etme özelliklerine göre değerlendirebiliriz. Özellikle erken yangın tesbiti ve yüksek çözünürlüklü yangın takibi konularında, var olan yangın önleme sistemlerine oranla kablosuz algılayıcı ağların (KAA) daha başarılı olduğu görülmüştür. Belirli bir orman bölgesine sıklıkla yerleştirilen çok sayıda algılayıcı sayesinde, çeşitli noktaların sıcaklık ve nem gibi bilgileri gerçek zamanlı ölçülüp yangınla mücadele merkezlerine hızlıca iletilebilmektedir. Bu çalışmada, FP7 FIRESENSE projesi kapsamında önerilen, KAA’ların yeteneklerini ve başarımını arttırmak amacıyla farklı tip cihazlardan oluşan KAA temelli heterojen bir yapının başarımını, gerçekçi yangın yayılım ve ağ benzetimi deneyleriyle değerlendiriyoruz. Ayrıca, gerçek cihazlarla yaptığımız deneylerden bir kesit sunuyoruz.
(English)
Forest fires are catastrophes which threaten the natural and human life. Economical, natural and cultural devastation caused by forest fires render the early detection and prevention of forest fires necessary. The success of a forest fire detection system can be assessed in terms of its accurate and quick detection capabilities. It is observed that wireless sensor networks (WSN) have a higher performance in especially early fire detection and high resolution fire monitoring compared to the existing fire detection systems. Temperature and humidity information of particular forest locations can be measured in real-time through the dense deployment of numerous sensors to a particular forest area and these information can be transmitted to the fire-fighting management center quickly. In this study, we evaluate the performance of a heterogeneous WSN-based architecture consisting of various types of devices, which is proposed in the scope of the FP7 FIRESENSE project to increase the capabilities of WSNs, with realistic fire propagation and network simulation experiments. Furthermore, we present a glance at the real life demonstrations.
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(Türkçe)
Orman yangınları dünyanın birçok yerinde büyük ölçüde çevresel ve ekonomik zararlara yo... more (Türkçe)
Orman yangınları dünyanın birçok yerinde büyük ölçüde çevresel ve ekonomik zararlara yol açmaktadır. Yangınları önleme ve erken tespit etme çabaları bu zararları engellemeyi veya azaltmayı amaçlamaktadır. Var olan orman yangını izleme sistemleri, yüksek çözünürlüklü ve gerçek zamanlı yangın takibi sağlayamamakta ve bu sebeple yangınlar erken ve hassas bir şekilde tespit edilememektedir. Kablosuz Algılayıcı Ağlar (KAA) bir ormanın çok sayıda noktasından sıcaklık ve nem gibi bilgileri gerçek zamanlı olarak ölçebilmekte ve bunları yangınla mücadele merkezlerine hızlıca aktarabilmektedir. Yangınların tahribat özelliğini göz önünde bulundurduğumuzda böyle bir sistemi gerçek bir yangın senaryosunda test etmek ve çalışır bir KAA’yı yok olma riskiyle karşı karşıya bırakmak maddi açıdan mümkün değildir. Bu yüzden benzetim deneyleri bu sistemin başarımını ölçmenin en uygun yoludur. Bu bildiride, KAA’ları gerçekçi yangın durumları için test etmek amacıyla gerçekçi yangın yayılım ve ağ benzetimini birleştiren, hem çevresel (orman yakıt modeli, rüzgar yönü ve şiddeti) hem de KAA’ya bağlı faktörlerin etkisini beraberce değerlendirebileceğimiz bir benzetim altyapısı sunuyoruz.
(English)
Forest fires lead to high amount of environmental and economic loss all over the world. Prevention and early detection efforts aim to eliminate or minimize the damage that will be caused by a fire incident. Current surveillance systems for forest fires do not provide dense real-time monitoring and hence they lack prevention or early detection of a fire threat. Wireless sensor networks (WSNs), on the other hand, can collect real-time information such as temperature and humidity from almost all points of a forest and can provide fresh and accurate data for the fire-fighting management center quickly. Since fires are destructive and burning a deployed WSN is not feasible, simulation is the appropriate way to assess the reporting capability of a WSN during a forest fire. In this paper, we propose a simulation platform which integrates WSN simulator with a realistic fire propagation simulator that is capable of evaluating the effect of environmental (forest fuel model, wind speed and direction) and WSN related factors.
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In order to study the performance of a wireless sensor network (WSN) under realistic fire scenari... more In order to study the performance of a wireless sensor network (WSN) under realistic fire scenarios, an environment is needed which both simulates the WSN and the temperature map variation in the simulated network. For this purpose, we need to model the temperature variation with time at specific pre-defined sensor node locations, as a wildfire spreads in the environment. Various temperature maps are provided by temperature field modelling algorithms, which have been developed and embedded in EFP, a realistic fire propagation simulator. These maps are fed into OPNET network simulation models to be able perform temperature based WSN simulations. In this paper, we present the details of this integration framework.
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Since fires are destructive and burning a deployed wireless sensor network (WSN) is not feasible,... more Since fires are destructive and burning a deployed wireless sensor network (WSN) is not feasible, simulation is the appropriate way for observing the reporting capability of a WSN during a forest fire. In this work, we evaluate WSN performance under realistic fire scenarios using OPNET modeler, which is fed with time based temperature field information over the deployment area provided by a realistic fire propagation simulator. Temperature information is used for data generation and sensor destruction in WSN simulations. We present the effects of both WSN related and enviromental factors on flat and clustered WSN topologies in terms of temperature reporting performance and freshness of temperature map.
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Signal Processing and …, Jan 1, 2012
Mobile sinks are proposed for load-balancing and achieving uniform energy-consumption in wireless... more Mobile sinks are proposed for load-balancing and achieving uniform energy-consumption in wireless sensor networks. However, advertising the location of the mobile sink to the network introduces an overhead in terms of energy consumption and packet delays. In this paper, we propose a new routing protocol, Ring Routing, which aims to minimize this overhead while preserving the advantages of mobile sinks. Simulation results show that the performance of Ring Routing is not very far from the lower bound in terms of delay and energy consumption.
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… , Mobility and Security …, Jan 1, 2012
Congestion is a challenging problem for sensor networks because it causes the waste of communicat... more Congestion is a challenging problem for sensor networks because it causes the waste of communication and reduces energy efficiency. In this article, problems for multimedia transmission over wireless multimedia sensor networks are examined and Sensor fUzzy-based Image Transmission (SUIT); a new cross-layer progressive image transport protocol is proposed as a solution. SUIT provides a fuzzy logic based congestion estimation and a novel congestion mitigation technique which decreases image quality on-the-fly at an acceptable level. In case of congestion, SUIT drops some packets of the frames in a smart way and thus transmits frames to the sink with lower, but acceptable quality. In this way, SUIT improves the continuity of the video streaming. We evaluate the performance of SUIT by comparing it with two example transport protocols, namely Event- to-Sink Reliable Transport and Fuzzy Logic Based Congestion Estimation, proposed for wireless sensor networks. According to our simulation results, SUIT provides better energy consumption, frame delivery, frame loss and frame latency performance than its competitors.
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Wireless Information Delivery Environment (WIDE) is a distributed data dissemination system, whic... more Wireless Information Delivery Environment (WIDE) is a distributed data dissemination system, which uses IEEE 802.11b technology. WIDE aims to deliver popular information services to registered mobile clients in WLAN hot spots. Data delivery is based on broadcasting and multicasting. S ystem specific reliability mechanisms are needed because of the unreliable medium and transport protocol. Reliability is assured with a combination of the Forward Error Correction (FEC), the data carousel and the ARQ techniques. This paper presents the proposed system architecture with the details of reliable data delivery mechanisms. Performance evaluation results of the proposed reliability mechanisms using the implemented prototype are also included in this paper.
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Journal Papers by Mehmet Yunus Dönmez
Conference Papers by Mehmet Yunus Dönmez
to the hotspot problem, which leads to the early death of the
nodes close to the sink, due to the concentration of data traffic
towards the sinks. However, the route updates employed by the
source nodes to determine the position of the sinks introduce an
overhead in terms of data reporting delays and energy consumptions.
On the other hand, decreased frequency of route updates
causes stale sink position information to be utilized for data
packets which results in suboptimal data dissemination paths.
In this paper, we investigate this inherent trade-off and provide
an insight on how to fine tune the route update parameters of a
mobile sink routing protocol. For this purpose, we define a system
employing a simple routing protocol and determine the optimal
operating points from the results obtained via simulations, under
varying degrees of route updates and sink mobility.
Orman yangınları doğal yaşamı ve insan yaşamını tehdit eden önemli bir felakettir. Doğaya, ekonomiye ve tarihsel kültüre verdikleri tahribat, orman yangınlarının erken tespit edilip büyümelerinin önlenmesini önemli kılmaktadır. Bir yangın tespit sisteminin başarısını, yangını en kısa zamanda ve hatasız tespit etme özelliklerine göre değerlendirebiliriz. Özellikle erken yangın tesbiti ve yüksek çözünürlüklü yangın takibi konularında, var olan yangın önleme sistemlerine oranla kablosuz algılayıcı ağların (KAA) daha başarılı olduğu görülmüştür. Belirli bir orman bölgesine sıklıkla yerleştirilen çok sayıda algılayıcı sayesinde, çeşitli noktaların sıcaklık ve nem gibi bilgileri gerçek zamanlı ölçülüp yangınla mücadele merkezlerine hızlıca iletilebilmektedir. Bu çalışmada, FP7 FIRESENSE projesi kapsamında önerilen, KAA’ların yeteneklerini ve başarımını arttırmak amacıyla farklı tip cihazlardan oluşan KAA temelli heterojen bir yapının başarımını, gerçekçi yangın yayılım ve ağ benzetimi deneyleriyle değerlendiriyoruz. Ayrıca, gerçek cihazlarla yaptığımız deneylerden bir kesit sunuyoruz.
(English)
Forest fires are catastrophes which threaten the natural and human life. Economical, natural and cultural devastation caused by forest fires render the early detection and prevention of forest fires necessary. The success of a forest fire detection system can be assessed in terms of its accurate and quick detection capabilities. It is observed that wireless sensor networks (WSN) have a higher performance in especially early fire detection and high resolution fire monitoring compared to the existing fire detection systems. Temperature and humidity information of particular forest locations can be measured in real-time through the dense deployment of numerous sensors to a particular forest area and these information can be transmitted to the fire-fighting management center quickly. In this study, we evaluate the performance of a heterogeneous WSN-based architecture consisting of various types of devices, which is proposed in the scope of the FP7 FIRESENSE project to increase the capabilities of WSNs, with realistic fire propagation and network simulation experiments. Furthermore, we present a glance at the real life demonstrations.
Orman yangınları dünyanın birçok yerinde büyük ölçüde çevresel ve ekonomik zararlara yol açmaktadır. Yangınları önleme ve erken tespit etme çabaları bu zararları engellemeyi veya azaltmayı amaçlamaktadır. Var olan orman yangını izleme sistemleri, yüksek çözünürlüklü ve gerçek zamanlı yangın takibi sağlayamamakta ve bu sebeple yangınlar erken ve hassas bir şekilde tespit edilememektedir. Kablosuz Algılayıcı Ağlar (KAA) bir ormanın çok sayıda noktasından sıcaklık ve nem gibi bilgileri gerçek zamanlı olarak ölçebilmekte ve bunları yangınla mücadele merkezlerine hızlıca aktarabilmektedir. Yangınların tahribat özelliğini göz önünde bulundurduğumuzda böyle bir sistemi gerçek bir yangın senaryosunda test etmek ve çalışır bir KAA’yı yok olma riskiyle karşı karşıya bırakmak maddi açıdan mümkün değildir. Bu yüzden benzetim deneyleri bu sistemin başarımını ölçmenin en uygun yoludur. Bu bildiride, KAA’ları gerçekçi yangın durumları için test etmek amacıyla gerçekçi yangın yayılım ve ağ benzetimini birleştiren, hem çevresel (orman yakıt modeli, rüzgar yönü ve şiddeti) hem de KAA’ya bağlı faktörlerin etkisini beraberce değerlendirebileceğimiz bir benzetim altyapısı sunuyoruz.
(English)
Forest fires lead to high amount of environmental and economic loss all over the world. Prevention and early detection efforts aim to eliminate or minimize the damage that will be caused by a fire incident. Current surveillance systems for forest fires do not provide dense real-time monitoring and hence they lack prevention or early detection of a fire threat. Wireless sensor networks (WSNs), on the other hand, can collect real-time information such as temperature and humidity from almost all points of a forest and can provide fresh and accurate data for the fire-fighting management center quickly. Since fires are destructive and burning a deployed WSN is not feasible, simulation is the appropriate way to assess the reporting capability of a WSN during a forest fire. In this paper, we propose a simulation platform which integrates WSN simulator with a realistic fire propagation simulator that is capable of evaluating the effect of environmental (forest fuel model, wind speed and direction) and WSN related factors.
to the hotspot problem, which leads to the early death of the
nodes close to the sink, due to the concentration of data traffic
towards the sinks. However, the route updates employed by the
source nodes to determine the position of the sinks introduce an
overhead in terms of data reporting delays and energy consumptions.
On the other hand, decreased frequency of route updates
causes stale sink position information to be utilized for data
packets which results in suboptimal data dissemination paths.
In this paper, we investigate this inherent trade-off and provide
an insight on how to fine tune the route update parameters of a
mobile sink routing protocol. For this purpose, we define a system
employing a simple routing protocol and determine the optimal
operating points from the results obtained via simulations, under
varying degrees of route updates and sink mobility.
Orman yangınları doğal yaşamı ve insan yaşamını tehdit eden önemli bir felakettir. Doğaya, ekonomiye ve tarihsel kültüre verdikleri tahribat, orman yangınlarının erken tespit edilip büyümelerinin önlenmesini önemli kılmaktadır. Bir yangın tespit sisteminin başarısını, yangını en kısa zamanda ve hatasız tespit etme özelliklerine göre değerlendirebiliriz. Özellikle erken yangın tesbiti ve yüksek çözünürlüklü yangın takibi konularında, var olan yangın önleme sistemlerine oranla kablosuz algılayıcı ağların (KAA) daha başarılı olduğu görülmüştür. Belirli bir orman bölgesine sıklıkla yerleştirilen çok sayıda algılayıcı sayesinde, çeşitli noktaların sıcaklık ve nem gibi bilgileri gerçek zamanlı ölçülüp yangınla mücadele merkezlerine hızlıca iletilebilmektedir. Bu çalışmada, FP7 FIRESENSE projesi kapsamında önerilen, KAA’ların yeteneklerini ve başarımını arttırmak amacıyla farklı tip cihazlardan oluşan KAA temelli heterojen bir yapının başarımını, gerçekçi yangın yayılım ve ağ benzetimi deneyleriyle değerlendiriyoruz. Ayrıca, gerçek cihazlarla yaptığımız deneylerden bir kesit sunuyoruz.
(English)
Forest fires are catastrophes which threaten the natural and human life. Economical, natural and cultural devastation caused by forest fires render the early detection and prevention of forest fires necessary. The success of a forest fire detection system can be assessed in terms of its accurate and quick detection capabilities. It is observed that wireless sensor networks (WSN) have a higher performance in especially early fire detection and high resolution fire monitoring compared to the existing fire detection systems. Temperature and humidity information of particular forest locations can be measured in real-time through the dense deployment of numerous sensors to a particular forest area and these information can be transmitted to the fire-fighting management center quickly. In this study, we evaluate the performance of a heterogeneous WSN-based architecture consisting of various types of devices, which is proposed in the scope of the FP7 FIRESENSE project to increase the capabilities of WSNs, with realistic fire propagation and network simulation experiments. Furthermore, we present a glance at the real life demonstrations.
Orman yangınları dünyanın birçok yerinde büyük ölçüde çevresel ve ekonomik zararlara yol açmaktadır. Yangınları önleme ve erken tespit etme çabaları bu zararları engellemeyi veya azaltmayı amaçlamaktadır. Var olan orman yangını izleme sistemleri, yüksek çözünürlüklü ve gerçek zamanlı yangın takibi sağlayamamakta ve bu sebeple yangınlar erken ve hassas bir şekilde tespit edilememektedir. Kablosuz Algılayıcı Ağlar (KAA) bir ormanın çok sayıda noktasından sıcaklık ve nem gibi bilgileri gerçek zamanlı olarak ölçebilmekte ve bunları yangınla mücadele merkezlerine hızlıca aktarabilmektedir. Yangınların tahribat özelliğini göz önünde bulundurduğumuzda böyle bir sistemi gerçek bir yangın senaryosunda test etmek ve çalışır bir KAA’yı yok olma riskiyle karşı karşıya bırakmak maddi açıdan mümkün değildir. Bu yüzden benzetim deneyleri bu sistemin başarımını ölçmenin en uygun yoludur. Bu bildiride, KAA’ları gerçekçi yangın durumları için test etmek amacıyla gerçekçi yangın yayılım ve ağ benzetimini birleştiren, hem çevresel (orman yakıt modeli, rüzgar yönü ve şiddeti) hem de KAA’ya bağlı faktörlerin etkisini beraberce değerlendirebileceğimiz bir benzetim altyapısı sunuyoruz.
(English)
Forest fires lead to high amount of environmental and economic loss all over the world. Prevention and early detection efforts aim to eliminate or minimize the damage that will be caused by a fire incident. Current surveillance systems for forest fires do not provide dense real-time monitoring and hence they lack prevention or early detection of a fire threat. Wireless sensor networks (WSNs), on the other hand, can collect real-time information such as temperature and humidity from almost all points of a forest and can provide fresh and accurate data for the fire-fighting management center quickly. Since fires are destructive and burning a deployed WSN is not feasible, simulation is the appropriate way to assess the reporting capability of a WSN during a forest fire. In this paper, we propose a simulation platform which integrates WSN simulator with a realistic fire propagation simulator that is capable of evaluating the effect of environmental (forest fuel model, wind speed and direction) and WSN related factors.