Ahmed Galib Reza

An efficient online signature verification scheme using dynamic programming of string matching

The necessity to authenticate individuals is rapidly increasing day by day with the explosive growth of E-commerce, E-finance, PDA, etc. Handwritten signature is the most widely used and easiest way to verify a person. Online signature verification is a very active and hot topic in the field of biometric research. It is a potential candidate to replace traditional password-based security system as the password can be forgotten, stolen or guessed. Online signature verification deals with both spatial and temporal features of signature. Therefore, it is difficult to forge. This paper proposes a novel online signature verification technique using dynamic programming of string matching. The performance of the proposed approach is evaluated for both genuine signatures and skilled forgeries on SVC2004 database. The proposed approach produces a False Acceptance Rate (FAR) of 4.13% and False Rejection Rate (FRR) of 5.5% with an Equal Error Rate (ERR) of 5%.

Throughput and delay performance analysis of feed-forward and feedback shared fiber delay line based hybrid buffering optical packet switch

In optical packet switching (OPS) network, packet contention is a critical factor which occurs at a switching node whenever two or more packets try to leave the switch fabric on the same output port, on the same wavelength, at the same time. Optical buffering approach based on fiber delay lines (FDLs) is the most cost-effective as well as the widely used solution for contention resolution. This paper analyzes the throughput and delay performance of our previously proposed hybrid buffering optical packet switch based on fixed-sized optical packets. This paper also investigates the role of FDL length in optical switch in terms of performance. Simulation result shows that our proposed FDL length selection scheme provides better performance. Moreover, throughput and delay performance of the switch under various FDL length selection scheme is compared. A series of computer simulations are performed in order to obtain the performance parameters of the switch.

Performance and Optical Cost Analysis of Shared Fiber Delay Line Based Two-Stage Optical Packet Switch

Packet contention is a critical issue in optical packet switching network which occurs at a switching node whenever two or more packets try to leave the switch fabric on the same output port, on the same wavelength, at the same time. In this paper, we investigate the performance of our previously proposed shared fiber delay line based two-stage optical packet switch for contention resolution. The performance of the switch is assessed in terms of throughput and average delay under both random and bursty traffic. In this paper, optical cost of the switch is determined based on fiber-to-chip coupling in order to estimate the hardware complexity, scalability. A series of computer simulations are performed in order to evaluate the performance of the switch. Simulation result indicates that proposed switch achieves satisfactory performance due to efficient use of buffer space.

Performance of two-stage shared fiber delay line optical packet switch under bursty traffic

Packet contention is a major issue in an optical packet switching network. It is not a trivial task to resolve contention due to lack of optical RAM technology. This article proposes a two-stage shared fiber delay line (FDL) optical packet switch for contention resolution. In this article, shared FDLs are used to buffer optical packets, in which a pool of buffer memory is shared among all switch output ports. Most of the existing optical buffering schemes are output-based which require a huge number of FDLs as well as a larger switch size that incur extra implementation cost. However, a shared buffering approach is considered in this article in order to reduce implementation cost. In this article, FDLs are implemented in two stages using an extremely simple auxiliary switch. The proposed switch architecture leads to more efficient use of buffer space. The superiority of the proposed switch architecture has been established by means of extensive simulations. The performance of the proposed switch is investigated under bursty traffic. Simulation result shows that the proposed switch can achieve satisfactory performance at the price of a reasonable amount of FDLs. Moreover, the significance of the proposed switch is confirmed by simulation.

Comparative Performance Study of WDM Packet Switch for Different Traffic Arrival Approach

Optical packet switching is a promising technology, which can integrate both data and optical network. In this paper, we present a comparative study of various traffic arrival approaches in WDM packet switches. The comparison is made based on packet loss rate and average delay under uniform and self-similar Pareto traffic. Computer simulations are performed in order to obtain the switch performance metrics. Study shows that burstiness of data traffic has a strong negative impact in the performance of WDM packet switches.

Contention resolution of synchronous fixed length optical packet with two stage shared fiber delay line optical packet switch

In optical packet switching network, packets may arrive at the switching node in an unorganized manner. Therefore, contention occurs and it is not a trivial task to resolve contention due to lack of optical RAM technology. Packet contention resolution is a major issue in optical packet switching (OPS). This paper focuses on contention resolution using fiber delay lines (FDLs) which are used to buffer contended packets in order to forward these packets to the desired output port to some future time slots. This paper proposes a two stage shared fiber delay line optical packet switch to resolve contention. FDLs are implemented in two stages using extremely simple auxiliary switch. The packet loss performance of the proposed switch is investigated with respect to average delay. Simulation result shows that, the packet loss rate of the proposed architecture under heavy traffic load of 0.9 is between ∼ 10−3 and ∼ 10−4 for a 32×32 switch using 64 FDLs, and zero packet loss rate achievable when traffic load is less than 0.8.

An effective hybrid buffering optical packet switch for contention resolution

Packet contention is a critical factor in optical packet switching network. It is not a trivial task to resolve due to lack of optical RAM technology. In order to resolve contention, optical buffering approach is used which are implemented using fiber delay lines (FDLs). Optical buffering approach is fundamental to many optical switch implementations to resolve contention. This paper focuses on contention resolution using fiber delay lines (FDLs). Most of the existing optical buffering schemes are output-based which require huge number of FDLs as well as larger switch size that incur extra implementation cost. Shared buffering approach is considered in this paper to reduce implementation cost. This paper investigates the performance of hybrid buffering optical packet switch to resolve contention, which uses a set of feed-forward shared fiber delay lines and a set of feedback shared fiber delay lines. Feed-forward FDLs are deployed as primary buffer and feedback FDLs are implemented as supplementary buffer. The hybrid buffered switch leads to more efficient use of the buffer space compared to output buffering. The performance of the switch is evaluated by means of simulation experiments. Simulation result shows that proposed hybrid buffering switch achieves lower packet loss rate at the price of a reasonable amount of FDLs. Moreover, the performance is compared with feed-forward shared buffering architecture to justify the significance of the switch.

Performance analysis of PingPong-128 keystream generator for wireless sensor networks

In this paper, we quantify the performance analysis of PingPong-128 keystream generator for wireless sensor networks. Although, PingPong-128 is not a standard stream cipher but still PingPong-128 keystream generator is an idea for resource constrained WSNs and can be widely used in the applications of secure communication, where the communication nodes have limited computation processing and storage capabilities while requiring sufficient levels of security. We present a performance comparison of PingPong-128 with other stream ciphers selected in European Project Ecrypt called eSTREAM project, namely Dragon, HC-128, and Rabbit. Apart from that, we are also considering RC-4 stream ciphers for comparison with pingpong-128 for wireless sensor networks.

Two-stage shared fiber delay line optical packet switch for contention resolution in optical packet-switching network

Abstract. Packet contention is a major issue in an optical packet-switching network. We focus on contention resolution using fiber delaylines (FDLs), which are used to buffer contended packets in order to for-ward these packets to the desired output port to some future time slots.Most of the existing optical buffering schemes are output based, whichrequire a huge number of FDLs as well as a larger switch size and incurextra implementation cost. A shared FDL buffering approach is consid-ered to reduce implementation cost. This paper proposes a two-stageshared FDL optical packet switch to resolve contention, where FDLs areimplemented in two stages using extremely simple auxiliary switch. Theperformance of the proposed switch architecture is evaluated throughsimulation under trivial and bursty traffic condition, in terms of packet lossrate and average delay. Other performance parameters, such as cross-talk, insertion loss, switch time, etc., are also discussed. Simulation resultshows that, the packet loss rate of the proposed architecture under heavytraffic load (