Amir Rizaan Abdul Rahiman

Solid state disk: A new storage device for video storage server

Solid state disk (SSD) is a new storage device that utilizes semiconductor memory chips (e.g. RAM, EEPROM, flash memory) to store data rather than using conventional spinning platters and moving heads found in conventional magnetic disk drive. The term of “solid state” means there are no moving parts involve in accessing, storing and retrieving required data on the drive. Several benefits offered by the SSD drives due to absent of moving mechanical components are high access speed, light weight, ruggedness, low latency, low power consumption, and silent operation. This paper discusses the architecture and the advantage offered by SSD in using the drive as a storage device in video server.

x-Folded TM

Massively parallel computers (MPCs) are currently being actively studied. Interconnection networks are used for the connection of a significant number of processors in such parallel systems because they are introduced as one of the key elements in parallel processing. Meshes, torus, and hypercubes were initially introduced as simple topologies of interconnection networks. At present, these have been replaced by more complicated topologies that also exhibit high performance. Because the diameter, average distance, and cost of topologies have a marked influence on network performance, this paper presents a novel topology called x-Folded TM, which is a TM topology that is folded according to the x-axis. For an n × n network, the diameter of an x-Folded TM is less than that of a TM and a torus, and the average distance of an x-Folded TM is less than that of a mesh, torus, and TM. Compared with mesh, torus, and TM networks, a Folded TM network presents reductions in the average distance, diameter, and cost, which accounts for its efficient performance. As observed from the presented simulation results, the performance of an x-Folded TM is similar to that of most torus networks and better than that of some torus networks. The results verify the effectiveness of the x-Folded TM network, as determined through its comparison with networks with other topologies.

Caching Scheme for Handheld Device in Mobile Video-on-Demand System

Mobile Video on demand (VOD) system is that allows mobile clients to browse and watch videos anywhere and anytime. In this system, the video server employs staggered broadcasting protocol to disseminate video to mobile clients within the MANET environment. In this protocol, video is divided into small segments and are repeatedly broadcasted within server’s channel in periodic basis. Clients can join any of the channels to receive the segments and begin to watch the video. The drawback of periodic broadcasting is it leads mobile clients to have a long waiting time (range in several minutes) due to the issue of channel transitions period. In this paper we focus on reducing the waiting time by proposing two caching schemes. This paper proposed first, a Neighbour-based caching scheme allows clients to get help from neighbour’s buffer for the playback, and a Relay-based caching scheme uses middle clients to relay the video from client to another client. Simulation shows that our two caching schemes can reduce clients delay tremendously in comparison with the case of no caching scheme.

Probability Based Page Data Allocation Scheme in Flash Memory

Today, flash memory (a type of semiconductor device) is becoming a popular data storage device in most electronic mobile devices. The reasons that make it become popular include small size and light weight nature, less noise, solid-state reliability, low power consumption, and better shock resistant. However, its two hardware characteristics, called out-place updating and garbage collection indirectly affect the performance of it superiority features. To overcome these limitations, this paper proposes a page allocation algorithm that based on page appearance regularity. The performance of the allocation scheme is confirmed by trace-driven simulations and the merit of the proposed algorithm is justified in terms of the number of active block requirement.

Adaptive routing algorithm in x-Folded TM topology

In recent days, more complicated interconnection topologies have been replaced with previously simple topologies that also exhibit high performance. x-Folded TM network is a TM network that is folded according to the imaginary x-axis in interconnection networks. For a x-Folded TM network, there is a reduction in the average distance and diameter which corroborates the efficient performance. Also many routing algorithms can be applied to interconnection network for the efficient use of network resources. This paper presents the effectiveness of the x-Folded TM network with the average latency and network throughput under the adaptive routing algorithm to improve dynamic communication performance. We evaluate the communication performance with simulating the topology under the adaptive routing algorithm. It is found from the result that the performance of a x-Folded TM network has been improved compared with other topologies.

Cleaning Process with Efficient Allocation Scheme Improves Flash Memory Performance

Flash memory is a non-volatile storage device that offers lots of superiority features. However, it has two characteristics namely: 1) Out-place updating and 2) Cleaning process that affects its performance as an efficient storage sub-system. Both characteristics influence the access time requirement in enabling the continuity of data storing and updating. In this paper, we propose an efficient data allocation scheme that takes into account the data popularity as the main indicator in making the allocation decision. Then, we unveil the importance of the allocation scheme in the block cleaning algorithm process. The simulation studies have shown that the integration between the block cleaning algorithm and the proposed data allocation scheme has significant impact on the cleaning process performance in terms of the number of block erasure operation and the number of active block requirements.

Block Cleaning Process in Flash Memory

Flash memory is a non-volatile storage device that can retain its contents when the power is switched off. Generally, it is a form of an electrically erasable programmable read-only memory (EEPROM) that offers several excellent features such as less noise, solid-state reliability, lower power consumption, smaller size, light weight, and higher shock resistant [1 – 5]. Flash memory acts as a slim and compact storage device. It’s main applications are such as compact flash (CF), secured digital (SD), and personal computer memory card international association (PCMCIA) cards, for storage and data transfer in most portable electronic gadgets such as mobile phones, digital cameras, personal digital assistants (PDAs), portable media players (PMPs), gobal positioning system receivers (GPS), just to name a few.

Towards accelerated agent-based crowd simulation for Hajj and Umrah

There are many scientific applications ranging from weather prediction to oil and gas exploration that requires high-performance computing. It aids industries and researchers to enrich further their advancements. With the advent of general purpose computing over GPUs, most of the applications above are shifting towards High-Performance Computing (HPC). Agent-based crowd simulation is one of the candidates that requires high-performance computing. This type of application is used to predict crowd movement in highly congested areas. One of the most crucial scenarios in which this application can be used is to mimic the movement of the multi-cultural crowd performing Hajj and Umrah in Masjid Al-Haram, Makkah. Adequate performance for an agent-based crowd system is a common problem in computer science. While the existing event planning software, specifically for Hajj and Umrah, are unable to provide the required performance. The main reason is the increasing amount of autonomous pilgrims every year. In this paper, we propose a high performance agent-based crowd simulation that represents pilgrim movement during these rituals. The performance is achieved by parallelizing an open source steering library called OpenSteer using CUDA over GPU. By using our technique, event organizers will be able to simulate large crowds and will also be able to predict whether the developed event plan is viable or not. We have also discussed the architecture and implementation of this parallel Hajj simulation.

Mathematical Modelling of Wormhole-Routed x-Folded TM Topology in the Presence of Uniform Traffic

Recently, x-Folded TM topology was introduced as a desirable design in k-ary n-cube networks due to the low diameter and short average distance. In this article, we propose a mathematical model to predict the average network delay for (\(k \times k\)) x-Folded TM in the presence of uniform traffic pattern. Our model accurately formulates the applied traffic pattern over network virtual channels based on the average distance and number of nodes. The mathematical results indicate that the average network delay for x-Folded TM topology is reduced when compared with other topologies in the presence of uniform traffic pattern. Finally, the results obtained from simulation experiments confirm that the mathematical model exhibits a significant degree of accuracy for x-Folded TM topology under the traffic pattern even in varied virtual channels.

A Performance Comparison of Deterministic and Adaptive Routing for an x-Folded TM Topology

This article focuses on a novel topology in interconnection networks which was called x-Folded TM. We explored the dynamic communication performance of this topology under various traffic patterns by designing new scheme for routing algorithms. In this scheme, the topology is partitioned to make the routing without deadlock in x-Folded TM topology. Using deterministic and adaptive routing, we have evaluated the performance of x-Folded TM topology in compare with Torus. A comparison of results reveals that the average delay grows steadily with the increase of injection rate until reaching saturation, which is the smallest rate of traffic for channel saturation in the network. Therefore, the achievements introduce x-Folded TM topology as efficient one in interconnection networks.