P. Mohapatra - Academia.edu (original) (raw)

Papers by P. Mohapatra

The rapid deployment of wireless mesh networks across universities and enterprises, and the perva... more The rapid deployment of wireless mesh networks across universities and enterprises, and the pervasiveness of mobile devices equipped with Wi-Fi connectivity, has resulted in a scenario wherein end users have the option to choose from a multitude of access points at any given location. Moreover, with the increasing availability of rich online content, there has been a steady increase in mobile Internet traffic. Since the choice of access point that a user associates with will directly impact his performance, it is imperative that there exist an efficient association control mechanism, in order to enhance the end user's experience. As part of this work, we propose Seeker, a novel framework for association control in wireless networks that utilizes ''available bandwidth'' as the design metric. The goal of Seeker is to assist the mesh network in making an intelligent decision regarding which access point a client should associate with. As part of our scheme, we implement and evaluate a passive tool to estimate available bandwidth in wireless networks. We then describe how we use this tool to implement our association control scheme, and evaluate it via extensive experiments on an outdoor testbed. Seeker takes into consideration the performance of the mesh backhaul, in addition to the client-to-AP link quality, thereby achieving significant advantages over traditional association control schemes for wireless-LANs.

The Domain Name System (DNS) provides a critical service for the Internet -mapping of user-friend... more The Domain Name System (DNS) provides a critical service for the Internet -mapping of user-friendly domain names to their respective IP addresses. Yet, there is no standard set of metrics quantifying the Quality of Domain Name Service or QoDNS, let alone a thorough evaluation of it. This paper attempts to fill this gap from the perspective of a DNS proxy/cache, which is the bridge between clients and authoritative servers. We present an analytical model of DNS proxy operations that offers insights into the design tradeoffs of DNS infrastructure and the selection of critical DNS parameters. After validating our model against simulation results, we extend it to study the impact of DNS cache poisoning attacks and evaluate various DNS proposals with respect to the QoDNS metrics. In particular, we compare the performance of two newly proposed DNS security solutions: one based on cryptography and one using collaborative overlays.

a b s t r a c t IEEE 802.11-based wireless mesh networks are being increasingly deployed in enter... more a b s t r a c t IEEE 802.11-based wireless mesh networks are being increasingly deployed in enterprize and municipal settings. A lot of work has been done on developing measurement-based schemes for resource provisioning and fault management in these networks. The above goals require an efficient monitoring infrastructure to be deployed, which can provide the maximum amount of information regarding the network status, while utilizing the least possible amount of network resources. However, network monitoring involves overheads, which can adversely impact performance from the perspective of the end user. The impact of monitoring overheads on data traffic has been overlooked in most of the previous works. It remains unclear as to how parameters such as number of monitoring agents, or frequency of reporting monitoring data, among others, impact the performance of a wireless network. In this work, we first evaluate the impact of monitoring overheads on data traffic, and show that even small amounts of overhead can cause a large degradation in the network performance. We then explore several different techniques for reducing monitoring overheads, while maintaining the objective (resource provisioning, fault management, and others) that needs to be achieved. Via extensive simulations and experiments, we validate the efficiency of our proposed approaches in reducing overheads, their impact on the quality of data collected from the network, and the impact they have on the performance of the applications using the collected data. Based on results, we conclude that it is feasible to make the current monitoring techniques more efficient by reducing the communication overheads involved while still achieving the desired application-layer objectives.

Peak Signal-to-Noise Ratio (PSNR) is the simplest and the most widely used video quality evaluati... more Peak Signal-to-Noise Ratio (PSNR) is the simplest and the most widely used video quality evaluation methodology. However, traditional PSNR calculations do not take the packet loss into account. This shortcoming, which is amplified in wireless networks, contributes to the inaccuracy in evaluating video streaming quality in wireless communications. Such inaccuracy in PSNR calculations adversely affects the development of video communications in wireless networks. This paper proposes a novel video quality evaluation methodology. As it not only considers the PSNR of a video, but also with modifications to handle the packet loss issue, we name this evaluation method MPSNR.

Acta Tropica, 2006

The sibling species composition of the Anopheles minimus and Anopheles dirus complexes is poorly ... more The sibling species composition of the Anopheles minimus and Anopheles dirus complexes is poorly known in the highly malarious north-eastern region of India where these two vector taxa are accountable for most of the malaria transmission among 30.7 million inhabitants. Prevalent members of these two complexes in this part of India were identified using sequences for the second internal transcribed spacer (ITS2) of ribosomal DNA. Anopheles baimaii (species D) of the An. dirus complex and An. minimus s.s. (species A) of the An. minimus complex were detected in Arunachal Pradesh, Assam, Meghalaya and Nagaland states. No intraspecific variation was observed in the ITS2 sequence (479 bp) of An. baimaii whereas a single substitution was detected in the ITS2 sequence (372 bp) of An. minimus from Nagaland state.

Parasitology Research, 2013

The rapid deployment of wireless mesh networks across universities and enterprises, and the perva... more The rapid deployment of wireless mesh networks across universities and enterprises, and the pervasiveness of mobile devices equipped with Wi-Fi connectivity, has resulted in a scenario wherein end users have the option to choose from a multitude of access points at any given location. Moreover, with the increasing availability of rich online content, there has been a steady increase in mobile Internet traffic. Since the choice of access point that a user associates with will directly impact his performance, it is imperative that there exist an efficient association control mechanism, in order to enhance the end user's experience. As part of this work, we propose Seeker, a novel framework for association control in wireless networks that utilizes ''available bandwidth'' as the design metric. The goal of Seeker is to assist the mesh network in making an intelligent decision regarding which access point a client should associate with. As part of our scheme, we implement and evaluate a passive tool to estimate available bandwidth in wireless networks. We then describe how we use this tool to implement our association control scheme, and evaluate it via extensive experiments on an outdoor testbed. Seeker takes into consideration the performance of the mesh backhaul, in addition to the client-to-AP link quality, thereby achieving significant advantages over traditional association control schemes for wireless-LANs.

The Domain Name System (DNS) provides a critical service for the Internet -mapping of user-friend... more The Domain Name System (DNS) provides a critical service for the Internet -mapping of user-friendly domain names to their respective IP addresses. Yet, there is no standard set of metrics quantifying the Quality of Domain Name Service or QoDNS, let alone a thorough evaluation of it. This paper attempts to fill this gap from the perspective of a DNS proxy/cache, which is the bridge between clients and authoritative servers. We present an analytical model of DNS proxy operations that offers insights into the design tradeoffs of DNS infrastructure and the selection of critical DNS parameters. After validating our model against simulation results, we extend it to study the impact of DNS cache poisoning attacks and evaluate various DNS proposals with respect to the QoDNS metrics. In particular, we compare the performance of two newly proposed DNS security solutions: one based on cryptography and one using collaborative overlays.

a b s t r a c t IEEE 802.11-based wireless mesh networks are being increasingly deployed in enter... more a b s t r a c t IEEE 802.11-based wireless mesh networks are being increasingly deployed in enterprize and municipal settings. A lot of work has been done on developing measurement-based schemes for resource provisioning and fault management in these networks. The above goals require an efficient monitoring infrastructure to be deployed, which can provide the maximum amount of information regarding the network status, while utilizing the least possible amount of network resources. However, network monitoring involves overheads, which can adversely impact performance from the perspective of the end user. The impact of monitoring overheads on data traffic has been overlooked in most of the previous works. It remains unclear as to how parameters such as number of monitoring agents, or frequency of reporting monitoring data, among others, impact the performance of a wireless network. In this work, we first evaluate the impact of monitoring overheads on data traffic, and show that even small amounts of overhead can cause a large degradation in the network performance. We then explore several different techniques for reducing monitoring overheads, while maintaining the objective (resource provisioning, fault management, and others) that needs to be achieved. Via extensive simulations and experiments, we validate the efficiency of our proposed approaches in reducing overheads, their impact on the quality of data collected from the network, and the impact they have on the performance of the applications using the collected data. Based on results, we conclude that it is feasible to make the current monitoring techniques more efficient by reducing the communication overheads involved while still achieving the desired application-layer objectives.

Peak Signal-to-Noise Ratio (PSNR) is the simplest and the most widely used video quality evaluati... more Peak Signal-to-Noise Ratio (PSNR) is the simplest and the most widely used video quality evaluation methodology. However, traditional PSNR calculations do not take the packet loss into account. This shortcoming, which is amplified in wireless networks, contributes to the inaccuracy in evaluating video streaming quality in wireless communications. Such inaccuracy in PSNR calculations adversely affects the development of video communications in wireless networks. This paper proposes a novel video quality evaluation methodology. As it not only considers the PSNR of a video, but also with modifications to handle the packet loss issue, we name this evaluation method MPSNR.

Acta Tropica, 2006

The sibling species composition of the Anopheles minimus and Anopheles dirus complexes is poorly ... more The sibling species composition of the Anopheles minimus and Anopheles dirus complexes is poorly known in the highly malarious north-eastern region of India where these two vector taxa are accountable for most of the malaria transmission among 30.7 million inhabitants. Prevalent members of these two complexes in this part of India were identified using sequences for the second internal transcribed spacer (ITS2) of ribosomal DNA. Anopheles baimaii (species D) of the An. dirus complex and An. minimus s.s. (species A) of the An. minimus complex were detected in Arunachal Pradesh, Assam, Meghalaya and Nagaland states. No intraspecific variation was observed in the ITS2 sequence (479 bp) of An. baimaii whereas a single substitution was detected in the ITS2 sequence (372 bp) of An. minimus from Nagaland state.

Parasitology Research, 2013