Poo Kuan Hoong

Review: Seamless handover integrated solution for video transmission over proxy mobile IPv6 in a micro mobility domain

Seamless communication is becoming one of the most important issues for the next generation of mobile and wireless networks. In this context, seamless is referred to users that are free to roam around different networks and at the same time stay connected without any disturbance to the ongoing session during the handover process from one network to another. The handover process between these networks spawns long delay or latency, high packet loss, and fewer throughputs which may degrade the performance of real-time applications during the handover process. Therefore, in order to resolve these problems, a new protocol has been proposed by Network-based Localized Mobility Management working group of Internet Engineering Task Force under network-based mobility management protocol. Although, this protocol managed to minimize the problems related to network switching, it still suffers several drawbacks during the handover process especially when the movement speed of mobile user is high. In this paper, we present a new approach which is a network-based mobility management protocol that aims to reduce the lengthy handover latency, jitter, high packet loss, and increase throughput and the performance of video transmission during the high speed mobility. The proposed approach namely Seamless Handover Integrated Solution consists of mobility prediction method, a set of Internet Control Message Protocol version 6 (ICMP6) messages which are effective in terms of handover optimization.

s-XML: An efficient mapping scheme to bridge XML and relational database

XML has recently emerged as the leading medium for data storage and data transfer over the World Wide Web due to its adaptable structure and flexibility in defining the tags. Many organizations had adopted XML as the principal facet in their online business applications. On the other hand, relational database is still widely used as the back-end database in most organizations. The diversity of these models need to be taken into account to ensure transparent and seamless integration. In this paper, we propose s-XML, an effective mapping scheme to bridge XML and relational database. Experimental results indicate that (1) s-XML is robust in terms of database storage and data loading; (2) s-XML processes query efficiently for complex chain and twig queries; and (3) s-XML is able to support large and skew-structured dataset as compared to relational DTD, Attribute and Edge approaches.

Road traffic prediction using Bayesian networks

Having prior road condition knowledge for planned or unplanned journeys will be beneficial in terms of not only time but potentially cost. Being able to obtain real-time information will further enhance these benefits. Current systems rely on huge infrastructure investments by governments to install cameras, road sensors and billboards to keep motorists informed. These efforts can only be, at best, available at pre-identified hotspots. Radio broadcast is an alternative, where they rely on reports by other motorists. However, such reports are often delayed and not tailored to individual motorist. Seeing the limitations of existing approaches to obtain real-time road conditions, this research work leverages on mobile devices that provide context sensitive information to propose a predictive analytics framework based on a Bayesian Network for road condition prediction. This paper aims to contribute to (i) defining a set of evidences (variables) that could potentially be utilized for road condition prediction and (ii) construction of a Bayesian Network model to predict road conditions. In conclusion, we presented a novel approach to provide potentially unlimited coverage of road traffic conditions with substantially reduced infrastructure investments. (5 pages)

NodesJoints: A framework for tree-based MANET in IEEE 802.11 infrastructure mode

In recent years there is a proliferation of ubiquitous portable computing devices which can be used in the absence of connection facilities in disconnected environments. A huge number of these devices are portable such as srnartphones, tablets and laptops. Without proper connection facilities, these devices could connect via ad hoc network as an alternative solution to overcome their needs of connectivity. However, generally most operating systems for smartphones and tablets do not support the feature of creating and even connecting to ad hoc networks. In addition, there are some drawbacks of ad hoc networks such as low performance and high energy consumption. These shortcomings motivate us to find a proper substitute network structure to efficiently fill the absence of ad hoc networks whenever using ad hoc is not feasible in practice. Finding an alternative way to establish ad hoc connection brings prominent use cases in several fields including disaster management, social networking, entertainment and marketing. Furthermore, it has the potential to open new prospects for further research. Our proposed solution, NodesJoints is meant to be used in the absence of ad hoc connectivity or existing network connections. It takes advantage of WNIC (wireless network interface card) virtualization and on-client AP (access point) feature to construct and connect a tree of nodes to perform message passing among the clients in infrastructure mode. Throughout this paper, our proposed framework is explicated for different stages of network life cycle such as network creation, routing table, route discovery and routing table update mechanisms.

Efficient Hybrid Push-Pull Based P2P Media Streaming System

Peer-to-Peer (P2P) communication is a popular protocol that has significant impacted and also changed the way for files being distributed over the large networks. Variants of P2P protocols are also applied for other media distribution such as audio and video streaming. The P2P protocol is widely adapted by researchers as a method to handle larger group of users. Cool streaming, the first large scale P2P streaming experiment till today, applied a mesh-based streaming system which has slowly evolved from a pure pull system to a hybrid push-pull system. In this paper, we present our proposed push-pull scheduling for P2P streaming that can heuristically select the most optimal frame to be pushed based on the rules that we designed. Our proposed solution incorporates the fast content distribution characteristic of both Push and Pull approaches. For performance evaluation, we compare our scheduling algorithm with the pure pull Cool streaming scheduling and Random push-pull scheduling where both scheduling serve as a benchmark in three main criteria -- end-to-end delay, frame miss-ratio and frame redundancy. Simulation results showed that our proposed heuristic push-pull overall outperformed the other scheduling schemes, where our proposed scheduling algorithm demonstrates as a better solution towards reducing mesh delay in P2P streaming.

Pthreads Performance Characteristics on Shared Cache CMP, Private Cache CMP and SMP

With the wide availability of chip multi-processing (CMP), software developers are now facing the task of effectively parallelizing their software code. Once they have identified the areas of parallelization, they will need to know the level of code granularity needed to ensure profitable execution. Furthermore, this problem multiplies itself with different hardware available. In this paper, we present a novel approach for fair comparison of the hardware configuration by simulation through configuring a pair of quad-core processors. The simulated configuration represents shared cache CMP, private cache CMP and symmetrical multiprocessor (SMP) environment. We then present a modified lmbench micro-benchmark suite to measure the cost of threading on these different hardware configurations. In our empirical studies, we observe that shared cache CMP exhibits better performance when the operating systems load balancer is highly active. However, the measurements also indicate that thread size is an important consideration where potential cache trashing can occur when sharing a cache between processing cores. Private cache CMP and SMP do not exhibit significant difference in our measurements. The techniques presented can be incorporated into integrated development environment, compilers and potentially even other run-time environments.

Towards Forecasting Low Network Traffic for Software Patch Downloads: An ARMA Model Forecast Using CRONOS

The usage of the Internet has become ubiquitous, even for desktop applications to assume that the computer system it is running on is connected to the Internet. Desktop applications rely on the Internet connectivity for software license authentication and also for maintenance through downloading of software patches. However, the latter can pose an annoyance to the user when he or she is relying on the Internet for real-time gaming or during heavy downloading of multimedia files. In this paper, we study the effectiveness of using the ARMA model to provide short range forecasting of Internet network TCP traffic for a single broadband line. The outcome of the research is positive and indicates that a step size of 30 seconds and irrespective of the window size gives the most accurate forecast. Through amplification of the results, this method shows strong indication that it can be implemented by software application developers to determine the most appropriate non-disruptive period to download their software patches. For small sized software patches, the software application can activate the download and a period of 120 seconds would be sufficient.

Dynamic threshold for imbalance assessment on load balancing for multicore systems

The introduction of multicore microprocessors has enabled smaller organizations to invest in high performance shared memory parallel systems. These systems ship with standard operating systems using preset thresholds for task imbalance assessment to activate load balancing. Unfortunately, this will unnecessarily trigger task migrations when the number of tasks is a few multiples of the number of processing cores. We illustrate this unnecessary task migration behavior through simulation and introduce a dynamic threshold for task imbalance assessment that is dependent on the number of tasks and the number of processing cores. This is as a replacement for the static threshold that is used by standard operating systems. With the dynamic threshold method, we are able to illustrate a performance gain of up to 17% on a synthetic benchmark and up to 25% gain using the Integer Sort Benchmark from the National Aeronautics and Space Administration (NASA) Advanced Supercomputing Parallel Benchmark Suite.

Mapping and Labeling XML Data for Dynamic Update

Expeditious growth of XML as a data exchange medium over the web has inspired many researchers to propose efficient and effective mapping and labeling schemes for proficient XML processing. The most crucial aspect that an approach needs to cater is the support for dynamic update. In this paper, we scrutinize and study the existing approaches in terms of the table schema, complexity and support for dynamic update. In addition, we suggest a mapping approach to map XML data into relational database, s-XML based on the persistent labeling scheme.

A comparative study of HITS vs PageRank algorithms for Twitter users analysis

Social Networks such as Facebook, Twitter, Google+ and LinkedIn have millions of users. These networks are constantly evolving and it is a good source of information, both explicitly and implicitly. The analysis of Social Network mainly focuses on the aspect of social networking with an emphasis on mapping relationships, patterns of interaction between user and content information. One of the common research topics focuses on the centrality measures where useful information of the connected people in the social network is represented in a graph. In this paper, we employed two link-based ranking algorithms to analyze the ranking of the users: HITS (Hyperlink-Induced Topic Search) and PageRank. We constructed Twitter user retweet-relationship graph using 21 days worth of data. Lastly, we compared the ranking sequence of the users in addition to their followers count against the average and also whether they are verified Twitter accounts. From the results obtained, both HITS and PageRank showed a similar trend, and more importantly highlighted the importance of the direction of the edges in this work.