Ruken Zilan | Universitat Politecnica de Catalunya (original) (raw)

Papers by Ruken Zilan

Ad hoc networks, 2015

Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual inf... more Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual information such as whether, when, and where the data is collected. In this context, hiding the existence of a WSN from adversaries is a desirable feature. One way to mitigate the sensor nodes' detectability is by limiting the transmission power of the nodes (i.e., the network is operating in the stealth mode) so that adversaries cannot detect the existence of the WSN unless they are within the sensing range of the WSN. Position dependent transmission power adjustment enables the network to maintain its level of stealth while allowing nodes farther from the network boundary to use higher transmission power levels. To mitigate the uneven energy dissipation characteristic, nodes that cannot dissipate their energies on communications reduce the amount of data they generate through computation so that the relay nodes convey less data. Dynamic data compression/decompression strategies reduce the amount of data to be communicated, thus, they achieve better energy savings when compared to static compression/decompression of data in which the data is always compressed independently of the power transmission strategy. In this study, we investigate various data compression strategies to maximize the lifetime of WSNs employing contextual privacy measures through a novel Mathematical Programming framework.

Multimedia Tools and Applications, Jul 1, 2011

Telecommunication Systems, Dec 3, 2009

This is a position paper on our views on security aspects of Wireless Multimedia Sensor Networks ... more This is a position paper on our views on security aspects of Wireless Multimedia Sensor Networks (Secure WMSNs). It is meant to serve as a brief survey. But, more importantly, it gives a perspective on how we foresee the future of this research area, its main challenges, and its future trends. We believe that this paper will spur new discussions and research ideas among the researchers from both the industry and the academic world.

Ad Hoc Networks, 2015

Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual inf... more Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual information such as whether, when, and where the data is collected. In this context, hiding the existence of a WSN from adversaries is a desirable feature. One way to mitigate the sensor nodes' detectability is by limiting the transmission power of the nodes (i.e., the network is operating in the stealth mode) so that adversaries cannot detect the existence of the WSN unless they are within the sensing range of the WSN. Position dependent transmission power adjustment enables the network to maintain its level of stealth while allowing nodes farther from the network boundary to use higher transmission power levels. To mitigate the uneven energy dissipation characteristic, nodes that cannot dissipate their energies on communications reduce the amount of data they generate through computation so that the relay nodes convey less data. Dynamic data compression/decompression strategies reduce the amount of data to be communicated, thus, they achieve better energy savings when compared to static compression/decompression of data in which the data is always compressed independently of the power transmission strategy. In this study, we investigate various data compression strategies to maximize the lifetime of WSNs employing contextual privacy measures through a novel Mathematical Programming framework.

Abstract. The objective of this work is to identify some of the traffic characteristics of Wirele... more Abstract. The objective of this work is to identify some of the traffic characteristics of Wireless Multimedia Sensor Networks (WMSN). Ap-plications such as video surveillance sensor networks make use of new paradigms related with computer vision and image processing techniques. These sensors do not send whole video sequences to the wireless sensor network, but objects of interest detected by the camera. In order to able to design appropriate networking protocols, a better understanding of the traffic characteristics of these multimedia sensors is needed. In this work1, we analyze the traffic differences between cameras that send whole coded images and those that first process and recognize objects of inter-est using Object Recognition techniques.

In this report basic principles of object recognition techniques are described and also some of t... more In this report basic principles of object recognition techniques are described and also some of the visual surveillance applications are given as examples of different techniques. In our study, suitable recognition techniques will be used for the traffic characterization of recognized images for wireless multimedia sensor networks. Today object recognition is one of the popular topics and takes more attention day by day. There is a wide application area for object recognition fields like industry (quality control etc.), medical image possessing, and military applications for instance, in the field

In this report basic principles of object recognition techniques are described and also some of t... more In this report basic principles of object recognition techniques are described and also some of the visual surveillance applications are given as examples of different techniques. In our study, suitable recognition techniques will be used for the traffic characterization of recognized images for wireless multimedia sensor networks.

Proceedings of the 10th ACM symposium on Performance evaluation of wireless ad hoc, sensor, & ubiquitous networks - PE-WASUN '13, 2013

In certain surveillance applications it is imperative that the deployed Wireless Sensor Network (... more In certain surveillance applications it is imperative that the deployed Wireless Sensor Network (WSN) is not detected by the adversaries before the intruding party is detected by the WSN (i.e., the WSN is in the stealth mode of operation). Limiting the transmission ranges of sensor nodes is an option to mitigate the compromising privacy of the WSN (i.e., data communication within the WSN is not detected from far away). However, using all sensor nodes with minimal energy transmission level has devastating effects on the network lifetime because some nodes acting as relays are heavily burdened by conveying the data flowing from an unproportionately high number of sensor nodes. Such an approach will lead to the premature death of certain subset of sensor nodes. Alternatively, sensor nodes' transmission ranges can be limited as a function of their distance to the network border. Even under this policy a subset of the nodes become hotspots. On the other hand, nodes close the border cannot dissipate their energies completely because they cannot relay much data due the limits imposed on their transmission ranges. One possible solution to mitigate the uneven energy dissipation characteristic is to let the nodes that cannot dissipate their energies on communications reduce the amount of data they generate through computation so that the relay nodes convey less data. In this study we create a novel Linear Programming (LP) framework to model the energy cost of contextual privacy and multi-level data compression in WSNs.

Nowadays, the evolution of network services provided at the edge of Internet increases the requir... more Nowadays, the evolution of network services provided at the edge of Internet increases the requirements of network applications. Such applications result in complexities thus, the processors need to execute more complex workloads that can deal not only with the packet header, but also with the packet payload (e.g. Deep Packet Inspection). Unlike common routing applications that show similar processing among packets, next-generation of network applications present variations in the processing procedure among packets. Therefore, different traffic behaviors can produce different process patterns and present different memory and processing requirements. The aim of this work is to present an ongoing work towards correlating Internet traffic features with variations of processing workloads on the next-generation of edge routers.

Yenilenebilir Enerji Kaynakları Sempozyumu

One of the major problems of wireless sensor networks is limited energy resources of sensors. Due... more One of the major problems of wireless sensor networks is limited energy resources of sensors. Due to the fact that sensors consume their energy and they are generally placed in remote or inhabited places, it is usually impossible to replace the battaries or recharge them. Thus it is crucial to increase the network lifetime by using the energy efficiently. For this purpose a natural approach is to activate only the necessary number of sensors and putting the others to sleep for each information transformation epoch. Besides this, chosen sensors should achieve an efficient coverage. In this study, by activating the minimum number of sensors for the area of coverage, network lifetime is increased and at the same time it is attempted to collect adequate data from the covered area. This way an optimization between QoS and network lifetime has been tried to be established.The area is divided into grids and it was attempted to make sure that one ON sensor is present in each grid. The resul...

ABSTRACT This study includes three parts; optimization of the geometry of absorber plate for flat... more ABSTRACT This study includes three parts; optimization of the geometry of absorber plate for flat plate collectors, construction of new absorber plate and efficiency tests of collectors. The new absorber plate, which is economic and resembling the commercially available absorber plate has been built by hot deep galvanization and by utilization of point welding. Before building the components of the system, some of the geometrical parameters, which influence the performance, have been optimized. Time constant and thermal efficiency of the constructed absorber plate has been measured. A new type of efficient and cheap absorber plate, which is made up of galvanized iron was constructed and its efficiency and price were determined together with that of three commercially available collectors constructed in Turkey, absorber plates of which are made up of aluminum and copper (�STEK Aluminum and Copper, DA�SAN -Copper). Time constants of the tested collectors are determined to be 137 seconds for �STEK Al, 75 seconds for �STEK Cu, 95 seconds for DA�SAN and 198 seconds for galvanized iron collector. For �STEK’s aluminum collector the y-axis intercept of the efficiency curve is 0.90, for �STEK’s copper collector it is 0.66; for DA�SAN’s copper it is 0.81 and for the collector that has galvanized iron absorber plate it is 0.82, which is increased up to 0.83 after new optimization. The price of the constructed absorber plate was DM 43, after new optimization it is increased to DM 53. For �STEK’s aluminum collector it is DM 100, for �STEK’s copper collector it is DM 60 and for DA�SAN’s copper collector it is DM 100.

... evaluation of the full SensEye system and compared it to a single-tier implementation of the ... more ... evaluation of the full SensEye system and compared it to a single-tier implementation of the ... The motivation is design of an image sensor device based on a CMOS and a ... Color blob tracking allows tracking the objects in real-time (identifies boundaries based on color changes ...

Advanced Computer Architecture and Compilation for Embedded Systems (ACACES'09), Jul 2009

Nowadays, the evolution of network services provided at the edge of Internet increases the requir... more Nowadays, the evolution of network services provided at the edge of Internet increases the requirements of network applications. Such applications result in complexities thus, the processors need to execute more complex workloads that can deal not only with the packet header, but also with the packet payload (e.g. Deep Packet Inspection). Unlike common routing applications that show similar processing among packets, next-generation of network applications present variations in the processing procedure among packets. Therefore, different traffic behaviors can produce different process patterns and present different memory and processing requirements.

Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual inf... more Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual information such as whether, when, and where the data is collected. In this context, hiding the existence of a WSN from adversaries is a desirable feature. One way to mitigate the sensor nodes’ detectability is by limiting the transmission power of the nodes (i.e., the network is operating in the stealth mode) so that adversaries cannot detect the existence of the WSN unless they are within the sensing range of the WSN. Position dependent transmission power adjustment enables the network to maintain its level of stealth while allowing nodes farther from the network boundary to use higher transmission power levels. To mitigate the uneven energy dissipation characteristic, nodes that cannot dissipate their energies on communications reduce the amount of data they generate through computation so that the relay nodes convey less data. Dynamic data compression/decompression strategies reduce the amount of data to be communicated, thus, they achieve better energy savings when compared to static compression/decompression of data in which the data is always compressed independently of the power transmission strategy. In this study, we investigate various data compression strategies to maximize the lifetime of WSNs employing contextual privacy measures through a novel mathematical programming framework.

Ad hoc networks, 2015

Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual inf... more Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual information such as whether, when, and where the data is collected. In this context, hiding the existence of a WSN from adversaries is a desirable feature. One way to mitigate the sensor nodes' detectability is by limiting the transmission power of the nodes (i.e., the network is operating in the stealth mode) so that adversaries cannot detect the existence of the WSN unless they are within the sensing range of the WSN. Position dependent transmission power adjustment enables the network to maintain its level of stealth while allowing nodes farther from the network boundary to use higher transmission power levels. To mitigate the uneven energy dissipation characteristic, nodes that cannot dissipate their energies on communications reduce the amount of data they generate through computation so that the relay nodes convey less data. Dynamic data compression/decompression strategies reduce the amount of data to be communicated, thus, they achieve better energy savings when compared to static compression/decompression of data in which the data is always compressed independently of the power transmission strategy. In this study, we investigate various data compression strategies to maximize the lifetime of WSNs employing contextual privacy measures through a novel Mathematical Programming framework.

Multimedia Tools and Applications, Jul 1, 2011

Telecommunication Systems, Dec 3, 2009

This is a position paper on our views on security aspects of Wireless Multimedia Sensor Networks ... more This is a position paper on our views on security aspects of Wireless Multimedia Sensor Networks (Secure WMSNs). It is meant to serve as a brief survey. But, more importantly, it gives a perspective on how we foresee the future of this research area, its main challenges, and its future trends. We believe that this paper will spur new discussions and research ideas among the researchers from both the industry and the academic world.

Ad Hoc Networks, 2015

Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual inf... more Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual information such as whether, when, and where the data is collected. In this context, hiding the existence of a WSN from adversaries is a desirable feature. One way to mitigate the sensor nodes' detectability is by limiting the transmission power of the nodes (i.e., the network is operating in the stealth mode) so that adversaries cannot detect the existence of the WSN unless they are within the sensing range of the WSN. Position dependent transmission power adjustment enables the network to maintain its level of stealth while allowing nodes farther from the network boundary to use higher transmission power levels. To mitigate the uneven energy dissipation characteristic, nodes that cannot dissipate their energies on communications reduce the amount of data they generate through computation so that the relay nodes convey less data. Dynamic data compression/decompression strategies reduce the amount of data to be communicated, thus, they achieve better energy savings when compared to static compression/decompression of data in which the data is always compressed independently of the power transmission strategy. In this study, we investigate various data compression strategies to maximize the lifetime of WSNs employing contextual privacy measures through a novel Mathematical Programming framework.

Abstract. The objective of this work is to identify some of the traffic characteristics of Wirele... more Abstract. The objective of this work is to identify some of the traffic characteristics of Wireless Multimedia Sensor Networks (WMSN). Ap-plications such as video surveillance sensor networks make use of new paradigms related with computer vision and image processing techniques. These sensors do not send whole video sequences to the wireless sensor network, but objects of interest detected by the camera. In order to able to design appropriate networking protocols, a better understanding of the traffic characteristics of these multimedia sensors is needed. In this work1, we analyze the traffic differences between cameras that send whole coded images and those that first process and recognize objects of inter-est using Object Recognition techniques.

In this report basic principles of object recognition techniques are described and also some of t... more In this report basic principles of object recognition techniques are described and also some of the visual surveillance applications are given as examples of different techniques. In our study, suitable recognition techniques will be used for the traffic characterization of recognized images for wireless multimedia sensor networks. Today object recognition is one of the popular topics and takes more attention day by day. There is a wide application area for object recognition fields like industry (quality control etc.), medical image possessing, and military applications for instance, in the field

In this report basic principles of object recognition techniques are described and also some of t... more In this report basic principles of object recognition techniques are described and also some of the visual surveillance applications are given as examples of different techniques. In our study, suitable recognition techniques will be used for the traffic characterization of recognized images for wireless multimedia sensor networks.

Proceedings of the 10th ACM symposium on Performance evaluation of wireless ad hoc, sensor, & ubiquitous networks - PE-WASUN '13, 2013

In certain surveillance applications it is imperative that the deployed Wireless Sensor Network (... more In certain surveillance applications it is imperative that the deployed Wireless Sensor Network (WSN) is not detected by the adversaries before the intruding party is detected by the WSN (i.e., the WSN is in the stealth mode of operation). Limiting the transmission ranges of sensor nodes is an option to mitigate the compromising privacy of the WSN (i.e., data communication within the WSN is not detected from far away). However, using all sensor nodes with minimal energy transmission level has devastating effects on the network lifetime because some nodes acting as relays are heavily burdened by conveying the data flowing from an unproportionately high number of sensor nodes. Such an approach will lead to the premature death of certain subset of sensor nodes. Alternatively, sensor nodes' transmission ranges can be limited as a function of their distance to the network border. Even under this policy a subset of the nodes become hotspots. On the other hand, nodes close the border cannot dissipate their energies completely because they cannot relay much data due the limits imposed on their transmission ranges. One possible solution to mitigate the uneven energy dissipation characteristic is to let the nodes that cannot dissipate their energies on communications reduce the amount of data they generate through computation so that the relay nodes convey less data. In this study we create a novel Linear Programming (LP) framework to model the energy cost of contextual privacy and multi-level data compression in WSNs.

Nowadays, the evolution of network services provided at the edge of Internet increases the requir... more Nowadays, the evolution of network services provided at the edge of Internet increases the requirements of network applications. Such applications result in complexities thus, the processors need to execute more complex workloads that can deal not only with the packet header, but also with the packet payload (e.g. Deep Packet Inspection). Unlike common routing applications that show similar processing among packets, next-generation of network applications present variations in the processing procedure among packets. Therefore, different traffic behaviors can produce different process patterns and present different memory and processing requirements. The aim of this work is to present an ongoing work towards correlating Internet traffic features with variations of processing workloads on the next-generation of edge routers.

Yenilenebilir Enerji Kaynakları Sempozyumu

One of the major problems of wireless sensor networks is limited energy resources of sensors. Due... more One of the major problems of wireless sensor networks is limited energy resources of sensors. Due to the fact that sensors consume their energy and they are generally placed in remote or inhabited places, it is usually impossible to replace the battaries or recharge them. Thus it is crucial to increase the network lifetime by using the energy efficiently. For this purpose a natural approach is to activate only the necessary number of sensors and putting the others to sleep for each information transformation epoch. Besides this, chosen sensors should achieve an efficient coverage. In this study, by activating the minimum number of sensors for the area of coverage, network lifetime is increased and at the same time it is attempted to collect adequate data from the covered area. This way an optimization between QoS and network lifetime has been tried to be established.The area is divided into grids and it was attempted to make sure that one ON sensor is present in each grid. The resul...

ABSTRACT This study includes three parts; optimization of the geometry of absorber plate for flat... more ABSTRACT This study includes three parts; optimization of the geometry of absorber plate for flat plate collectors, construction of new absorber plate and efficiency tests of collectors. The new absorber plate, which is economic and resembling the commercially available absorber plate has been built by hot deep galvanization and by utilization of point welding. Before building the components of the system, some of the geometrical parameters, which influence the performance, have been optimized. Time constant and thermal efficiency of the constructed absorber plate has been measured. A new type of efficient and cheap absorber plate, which is made up of galvanized iron was constructed and its efficiency and price were determined together with that of three commercially available collectors constructed in Turkey, absorber plates of which are made up of aluminum and copper (�STEK Aluminum and Copper, DA�SAN -Copper). Time constants of the tested collectors are determined to be 137 seconds for �STEK Al, 75 seconds for �STEK Cu, 95 seconds for DA�SAN and 198 seconds for galvanized iron collector. For �STEK’s aluminum collector the y-axis intercept of the efficiency curve is 0.90, for �STEK’s copper collector it is 0.66; for DA�SAN’s copper it is 0.81 and for the collector that has galvanized iron absorber plate it is 0.82, which is increased up to 0.83 after new optimization. The price of the constructed absorber plate was DM 43, after new optimization it is increased to DM 53. For �STEK’s aluminum collector it is DM 100, for �STEK’s copper collector it is DM 60 and for DA�SAN’s copper collector it is DM 100.

... evaluation of the full SensEye system and compared it to a single-tier implementation of the ... more ... evaluation of the full SensEye system and compared it to a single-tier implementation of the ... The motivation is design of an image sensor device based on a CMOS and a ... Color blob tracking allows tracking the objects in real-time (identifies boundaries based on color changes ...

Advanced Computer Architecture and Compilation for Embedded Systems (ACACES'09), Jul 2009

Nowadays, the evolution of network services provided at the edge of Internet increases the requir... more Nowadays, the evolution of network services provided at the edge of Internet increases the requirements of network applications. Such applications result in complexities thus, the processors need to execute more complex workloads that can deal not only with the packet header, but also with the packet payload (e.g. Deep Packet Inspection). Unlike common routing applications that show similar processing among packets, next-generation of network applications present variations in the processing procedure among packets. Therefore, different traffic behaviors can produce different process patterns and present different memory and processing requirements.

Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual inf... more Contextual privacy in Wireless Sensor Networks (WSNs) is concerned with protecting contextual information such as whether, when, and where the data is collected. In this context, hiding the existence of a WSN from adversaries is a desirable feature. One way to mitigate the sensor nodes’ detectability is by limiting the transmission power of the nodes (i.e., the network is operating in the stealth mode) so that adversaries cannot detect the existence of the WSN unless they are within the sensing range of the WSN. Position dependent transmission power adjustment enables the network to maintain its level of stealth while allowing nodes farther from the network boundary to use higher transmission power levels. To mitigate the uneven energy dissipation characteristic, nodes that cannot dissipate their energies on communications reduce the amount of data they generate through computation so that the relay nodes convey less data. Dynamic data compression/decompression strategies reduce the amount of data to be communicated, thus, they achieve better energy savings when compared to static compression/decompression of data in which the data is always compressed independently of the power transmission strategy. In this study, we investigate various data compression strategies to maximize the lifetime of WSNs employing contextual privacy measures through a novel mathematical programming framework.