Aasia Riasat's research while affiliated with Pakistan Institute of Tourism & Hotel Management Karachi and other places

Publications (54)

Conference Paper
Full-text available
One of the most common optimistic synchronization protocols for parallel simulation is the Time Warp algorithm proposed by Jefferson [12]. Time Warp algorithm is based on the virtual time paradigm that has the potential for greater exploitation of parallelism and, perhaps more importantly, greater transparency of the synchronization mechanism to th...
Article
Full-text available
Time Wrap algorithm is a well-known mechanism of optimistic synchronization in a parallel discrete-event simulation (PDES) system. It offers a run time recovery mechanism that deals with the causality errors. For an efficient use of rollback, the global virtual time (GVT) computation is performed to reclaim the memory, commit the output, detect the...
Article
Full-text available
Multiuser detection is an important technology in wireless CDMA systems for improving both data rate as well as user capacity. However, the computational complexity of multiuser detection prevents the widespread use of this technique. Most of the CDMA systems today and in the near future will continue to use the conventional matched filter with its...
Article
Full-text available
The capacity of mobile ad hoc network (MANET) is typically determined by the size of network, routing protocol, mobility and the interactions that occur between the nodes. Moreover, these critical parameters cause the loss rate that has severed impact on the performance of the MANET. This situation even becomes worst when these critical parameters...
Chapter
Full-text available
This paper presents a new scheme for the Distance Source Routing (DSR) protocol which shows the improvement over the two major metrics of the DSR protocol: Route Discovery and Route Maintenance. In addition, we present a mathematical model that includes probability density function for these two observed metrics. Our simulation results demonstrate...
Chapter
Full-text available
In the present scenario, improvement in the data rate, network capacity, scalability, and the network throughput are some of the most serious issues in wireless mesh networks (WMN). Specifically, a major obstacle that hinders the widespread adoption of WMN is the severe limits on throughput and the network capacity. This chapter presents a discussi...
Article
Full-text available
Wireless Multiuser receivers suffer from their relatively higher computational complexity that prevents widespread use of this technique. In addition, one of the main characteristics of multi-channel communications that can severely degrade the performance is the inconsistent and low values of SNR that result in high BER and poor channel capacity....
Article
Full-text available
A new transformation matrix (TM) algorithm for reducing the computational complexity of multiuser receivers for DS-CDMA wireless system is presented. Next generation multiuser wireless receivers will need to use low computational complexity algorithm in order to perform both fast signal detection and error estimation. Several multiuser signal detec...
Conference Paper
Full-text available
In this paper we investigate on a special type of job scheduler for distributed heterogeneous systems called the switch and feedback job scheduler. The main objective of the centralized job scheduler is to achieve maximum performance with reduced waiting time and faster response time for independent tasks by reordering the processor queue list base...
Conference Paper
Full-text available
Extensive studies have been carried out for reducing the handover time of wireless network at medium access layer (MAC). However, none of them depicts the impact of reduced handover time on the overall performance of wireless networks. This paper presents the methodology that can be used to effectively reduce the handover time. Our proposed model i...
Conference Paper
Full-text available
A new transformation matrix technique for reducing the complexity of a multiuser receiver for DS-CDMA system is presented. The reduction in complexity of multiuser receiver would result in better bit error rate (BER) performance. The reduction in error rate would allow us to maximize the data throughput of a communication network by minimizing the...
Conference Paper
Full-text available
End-system multicasting (ESM) is a promising application-layer scheme that has been recently proposed for implementing multicast routing in the application layer as a practical alternative to the IP multicasting. Moreover, ESM is an efficient application layer solution where all the multicast functionality is shifted to the end users. However, the...
Article
Full-text available
Wireless Multiuser receivers suffer from their relatively higher computational complexity that prevents widespread use of this technique. In addition, one of the main characteristics of multi-channel communications that can severely degrade the performance is the inconsistent and low values of SNR that result in high BER and poor channel capacity....
Conference Paper
Full-text available
This paper presents a new scheme for the Distance Source Routing (DSR) protocol which shows the improvement over the two major metrics of the DSR protocol: Route Discovery and Route Maintenance. In addition, we present a mathematical model that includes probability density function for these two observed metrics. Our simulation results demons...
Chapter
Full-text available
High performance packet switching networks are being deployed to provide sufficient data bandwidth for end users 3G services such as video streaming and broadband like data services. The use of high performance networks is, therefore, essential to the success of any 3G service. However, in practice, the deployment of High performance packet switchi...
Conference Paper
Full-text available
The capacity of mobile ad hoc network (MANET) is typically determined by the size of network, routing protocol, mobility and the interactions that occur between the nodes. Moreover, these critical parameters cause the loss rate that has severed impact on the performance of the MANET. This situation even becomes worst when these critical parameters...
Conference Paper
Full-text available
This paper presents an efficient routing algorithm for the Mesh-Hypercube (M-H) network. The M-H network is one of the new interconnection networking techniques use to build high performance parallel computers. The combination of M-H networks offers high connectivity among multiple nodes, fault-tolerance, and load scalability. However, the performa...
Conference Paper
Full-text available
Null message algorithm (NMA) is one of the efficient conservative time management algorithms that use null messages to provide synchronization between the logical processes (LPs) in a parallel discrete event simulation (PDES) system. However, the performance of a PDES system could be severely degraded if a large number of null messages need to be g...
Conference Paper
Full-text available
A closed-form expression to determine an average error rate for synchronous DS-CDMA multi-user detector is derived based on the transformation matrix (TM) algorithm proposed in [1]. The derived expression for average bit error rate (BER) can be used to produce higher and consistent values of signal-to-noise ratio (SNR) that consequently results goo...
Conference Paper
Full-text available
This paper presents a new transformation matrix system for reducing the computational complexity of multiuser receiver. The proposed system observes the coordinates of the constellation diagram to determine the location of the transformation points. Since most of the decisions are correct, we can reduce the number of required computations by using...
Conference Paper
Full-text available
Null message algorithm is an important conservative time management protocol in parallel discrete event simulation systems for providing synchronization between the distributed computers with the capability of both avoiding and resolving the deadlock. However, the excessive generation of null messages prevents the widespread use of this algori...
Conference Paper
Full-text available
Multiuser detectors suffer from their relatively higher computational complexity that prevents widespread use of this technique. In addition, one of the main characteristics of multichannel communications that can severely degrade the performance is the inconsistent values of processing gain (PG) that result in high multiple access interference (MA...
Conference Paper
Full-text available
This paper presents the implementation of a secure application for an academic institution that offers numerous services to both students and the faculty. The primary focus of this paper is to provide a technical implementation of a new architecture for encrypting the database. The scope of this paper mainly includes but is not limited to symmetric...
Conference Paper
The performance of a conservative time management algorithm in a distributed simulation system degrades significantly if a large number of null messages are exchanged across the logical processes in order to avoid deadlock. This situation gets more severe when the exchange of null messages is increased due to the poor selection of key parameters su...
Conference Paper
Full-text available
The Time Wrap algorithm [3] offers a run time recovery mechanism that deals with the causality errors. These run time recovery mechanisms consists of rollback, anti-message, and Global Virtual Time (GVT) techniques. For rollback, there is a need to compute GVT which is used in discrete-event simulation to reclaim the memory, commit the output, dete...
Article
Full-text available
A complex relationship between the semantic and the dynamic web is derived based on the concepts of ontology engineering. The resultant complex relationship can then be used to construct new generation intelligent agent-based software. Although the World Wide Web (WWW) was originally designed as a distributed information space that supported human...
Conference Paper
Full-text available
In the present scenario, improvement in the data rate, scalability and throughput are some of the most time consuming issues in Wireless Mesh Networks (WMN). This paper discusses one of our proposed methods, i.e., improving data rate in Wireless Mesh Networks by redefining the mesh transceiver with the help of OFDM and CDMA called OFCD. The details...
Conference Paper
Full-text available
Extensive studies have been carried out for reducing the handover time of wireless network at medium access layer (MAC). However, none of them depicts the impact of reduced handover time on the overall performance of wireless networks. This paper presents the methodology that can be used to effectively reduce the handover time. Our proposed model i...
Chapter
Full-text available
Due to increasing demand for simulation and modeling, efforts are needed to build up more powerful simulation and modeling methodologies that can help to facilitate learning complex dynamic systems. By learning we mean the acquisition of knowledge, skills and experience for better and faster learning of the various types of complex dynamic systems....
Conference Paper
Full-text available
Extensive research and studies have shown that the hypercube network is one of the most widely used techniques to build high performance parallel computers and it offers strong hierarchical structure with high symmetry properties. However, the performance of hypercube networks is mainly dependent on the link consistency between the nodes. Due to un...
Chapter
Full-text available
As ATM network is designed for broad band transmission that is high data rate (25 Mbps to 2.5 Gbps) and supports the transmission of every kind of data, congestion control and delay have been important issues for ATM networks. Data transmission is done in the form of cell (53 bytes) relay. Hence, cell sequence and the error control have to be carri...
Chapter
Due to increasing demand for simulation and modeling, efforts are needed to build up more powerful simulation and modeling methodologies that can help to facilitate learning complex dynamic systems. By learning we mean the acquisition of knowledge, skills and experience for better and faster learning of the various types of complex dynamic systems....
Conference Paper
Full-text available
The Internet is experiencing the demand of high-speed real-time applications, such as live streaming multimedia, videoconferencing, and multiparty games. IP multicast is an efficient transmission technique to support these applications. However, there are several architectural issues in this technique that hinder the development and the deployment...
Conference Paper
Full-text available
The capacity of mobile ad hoc network (MANET) is typically determined by the size of network, routing protocol, mobility and the interactions that occur between the nodes. Moreover, these critical parameters cause the loss rate that has severed impact on the performance of the MANET. This situation even becomes worst when these critical parameters...
Conference Paper
Full-text available
As ATM network is designed for broad band transmission that is high data rate (25 Mbps to 2.5 Gbps) and supports the transmission of every kind of data, congestion control and delay have been important issues for ATM networks. Data transmission is done in the form of cell (53 bytes) relay. Hence, cell sequence and the error control have to be carri...
Chapter
Full-text available
The performance of a conservative time management algorithm in a distributed simulation system degrade s significantly if a large number of null messages are exchanged across the logical processes in order to avoid deadlock. This situation gets more severe when the exchange of null messages is increased due to the poor selection of key parameters s...
Conference Paper
Full-text available
A sensor network is made up of numerous small independent sensor nodes with sensing, processing and communicating capabilities. The sensor nodes have limited battery and a minimal amount of on-board computing power. A self-adaptive methodology that utilizes the source and path redundancy techniques to efficiently reduce the required energy consumpt...
Conference Paper
Full-text available
Global virtual time (GVT) is used in parallel discrete event simulations to reclaim memory, commit output, detect termination, and handle errors. Mattern 's [I] has proposed G VT approximation with distributed termination detection algorithm. This algorithm works fine and gives optimal performance in terms of accurate GVT computation at the expense...
Conference Paper
Full-text available
In this paper, a new scheme for reducing the computational complexity of multiuser receivers is presented. It utilizes the transformation matrix (TM) algorithm to improve the performance of multiuser receivers by effectively reducing the bit error rate (BER). In addition, a deterministic formalization of the processing gain (PG) for a multiuser DS...
Conference Paper
Full-text available
Multiuser detection is an important technology in wireless CDMA systems for improving both data rate as well as user capacity. However, the computational complexity of multiuser detection prevents the widespread use of this technique. Most of the CDMA systems today and in the near future will continue to use the conventional matched filter with its...
Conference Paper
Full-text available
This paper presents an analytical model for the performance of a generic reconfigurable coprocessor (RC) system. The system is characterized by a standard processor with a portion that is reconfigurable. We describe a general performance model for the speedup of a generic RC system. We demonstrate how different parameters of speedup model can affec...
Conference Paper
Full-text available
RFID (Radio Frequency Identification) interference is one of the most important issues for RFID applications. The dense-reader mode in Class 1 Gen2 in EPC-global is one of the solutions which can reduce the interference problem. This paper presents a new software based solution that can be used for improving the performance of dense-reader mode thr...
Chapter
Full-text available
With the tremendous applications of the wireless sensor network, self-localization has become one of the challenging subject matter that has gained attention of many researchers in the field of wireless sensor network. Localization is the process of assigning or computing the location of the sensor nodes in a sensor network. As the sensor nodes are...
Article
Full-text available
New analytical and the speedup models for evaluating the performance of a generic reconfigurable coprocessor (RC) system are presented. We present a generic performance model for the speedup of a generic RC system. We demonstrate how different parameters of speedup model can affect the performance of reconfigurable system (RS). In addition, we impl...
Article
Full-text available
Due to increasing demand for simulation and modeling, efforts are needed to build up more powerful simulation and modeling methodologies that can help to facilitate learning complex dynamic systems. By learning we mean the acquisition of knowledge, skills and experience for better and faster learning of the various types of complex dynamic systems....
Article
Full-text available
With the tremendous applications of the wireless sensor network, self-localization has become one of the challenging subject matter that has gained attention of many researchers in the field of wireless sensor network. Localization is the process of assigning or computing the location of the sensor nodes in a sensor network. As the sensor nodes are...

Citations

... Conservative protocols fundamentally maintain causality in event execution by strictly disallowing the processing of events out of time-stamp order [4]. Some recent research on conservative algorithms in DES can be found in [11][12][13][14]. An effort to combine conservative and optimistic synchronization algorithms on a common layered architecture framework is proposed in [15]. ...
... Source Routing (DSR) [24], and Temporarily Ordered Routing Algorithm (TORA) [25]. Hybrid protocols are a mix between the previous types where routes are kept proactively for nearby nodes and reactively 2.2. ...
... The end to end packet delay in mobile ad-hoc network is complex because it depends on many influential factors as path length from source to destination, average neighbours of intermediate hops and interference. [5] [6] On the basis of available papers, it has been review in [7] that delay is a dynamic metric which is built upon the following factors multi-hop nature of network, Mobility, path length, Dynamic topology, Link-Breakage, limited battery life, bandwidth issues and Selfish behaviour of nodes. And in a dense network these factors show their affect even more than in a sparce network. ...
... Processors use EBs to record the number of events sent and received by LPs, as well as the LVT of each LP and the timestamps of events in transit. GVT computation via the EB approach can avoid message acknowledgement, which is a common solution for the problem of transient event in distributed GVT algorithms [16,17,20,21]. In our algorithm, the size of Event-Bulk is negatively correlated with the accuracy of GVT computation but positively correlated with the performance of GVT computation. ...
... Due to its nature, it requires the definition of some artificial events with the aim of making the simulation proceed. The number of such messages introduced by the synchronization algorithm can be very large [74,75]. Obviously, this communication overhead has a big effect on the WCT. ...
... The solution to the system Cz + W ′ = D may not yield unique solution because D does not lie in the column space of C. So, an approximate solution is needed in this scenario. Basically, this approximate solution is projected solution onto the column space of C. It is at the minimum distance from all the column vectors of C. Therefore, a least square approach [33] is used in this context. The advantage of this approach lies in the fact that non-linear Equations 16 can be converted to linear one by subtracting out two equations. ...
... This approach produced the highest message delivery percentage as seen in Message Delay and Hop count: Another evaluation criteria is the average hop count of the multicast messages. The hop count of a packet is defined as the number of routers traversed by a packet between its source and destination [17], which is in this case the number of hosts that a message passes from the source to the destination [18]. As seen in Figures 8 and 9 and Tables 2 and 3 when the number of users is small, the average hop count of LA-NICE and NICE, as well as the maximum hop count is almost the same, however as the number of users increase LA-NICE has less number of hops leading to less delay in delivering the messages. ...
... In order to collect the information, two methods of scanning are commonly available in the literature: active scanning and passive scanning [42]. Active scanning refers to keeping on all the interfaces continuously active while passive scanning refers to the periodic activation of the interfaces for verifying the availability of new networks. ...
... Consequently, the use of matrix with the Mattern's algorithm provides several advantages such as it reduces the number of memory fetches, saves memory, increases the processor speed, and improves the latency. We incorporated the butterfly barrier as it has great performance when compared to the other broadcast and the centralized barriers [7,19,20]. ...
... The degree and total number of links of the HC is less than those of hypercube. In hypercube [10] the node degree of each node is a logarithmic function of the total number of nodes, which is a drawback of the topology. Consequently, the hypercube topology is not a good candidate for interconnection network for a very large parallel computer that might contain hundreds of thousands of nodes due to limitations concerning integrated circuit technology and port number. ...