Keat Keong Phang

ENHANCED SOFTWARE DEVELOPMENT EFFORT AND COST ESTIMATION USING FUZZY LOGIC MODEL

The development of software has always been characterized by parameters that possess certain level of fuzziness. This requires that some degree of uncertainty be introduced in the models, in order to make the models realistic. Fuzzy logic fares well in this area. Many of the problems of the existing effort estimation models can be solved by incorporating fuzzy logic. Besides, fuzzy logic had been combined with algorithmic, non-algorithmic effort estimation models as well as a combination of them to deal with the inherent uncertainty issues. This paper also described an enhanced fuzzy logic model for the estimation of software development effort. The model (FLECE) possesses similar capabilities as the previous fuzzy logic model. In addition to that, the enhancements done in FLECE improved the empirical accuracy of the previous model in terms of MMRE (Mean Magnitude of Relative Error) and threshold-oriented prediction measure or prediction quality (pred).

SODA: An Algorithm to Guarantee Correctness of Concurrent Transaction Execution in Mobile P2P Databases

This paper proposes an optimistic concurrency control (CC) algorithm, called Sequential Order with Dynamic Adjustment (SODA), that guarantees timely and correct execution of concurrent transaction in Mobile P2P databases. In Mobile P2P, as every peer is fully autonomous, needs timely response and has inherent characteristics (mobility, low bandwidth, limited battery power, limited storage and frequent disconnections), existing CC algorithms cannot be applied directly. SODA is an effort to fill in this gap. The analysis of SODA shows that it is able to improve the response time by applying the concept of sequential order and reduce the transaction abort rate by dynamically adjusting the sequential order.

A query transformation framework for automated structured query construction in structured retrieval environment

Current research and development of structured retrieval systems allow search communities to tap into structured resources over the web. These resources have advantages compared with the normal web resources as they have additional annotations that can be utilized when composing a search request. However, structured query languages used by these retrieval systems are not meant for normal searchers. This article addresses this problem by automating the construction of a structured query from a keywords query that is more familiar to the web search user. As a result, a query transformation framework is proposed. Different from the existing framework, which is a one-time solution, our proposed framework has greater flexibility in accommodating new structured query languages and different collection types. A novel intermediate query representation is designed to handle transformation to multiple types of query languages, whereas a context-based probabilistic model is designed to capture the structural features of both homogeneous and heterogeneous collections. Experimental results show that the structured queries generated from our framework give promising results compared with their source queries. This finding suggests that the framework can potentially be used in search applications to improve their search features.

Fuzzy database framework-relational versus object-oriented model

The paper describes: fuzzy data and linguistic qualifiers; fuzzy data representation and retrieval; fuzzy database aspects; relational and object-oriented models; and the advantages of using the object-oriented database framework in a fuzzy database. A prototype fuzzy object-oriented database system (FOODS) has been implemented to demonstrate its feasibility.

Issues of Establishing a Campus-wide Computational Grid Infrastructure in the GERANIUM Project

A campus-wide grid and cluster infrastructure using the Rocks clustering software is established. The infrastructure, namely Grid-Enabled Research Network and Info-structure of University of Malaya (GERANIUM), comprises five distinct clusters located at different faculties and institutes. In this paper, the GERANIUM topology and architecture are presented, and issues and experiences concerned are discussed.

Fuzzy Active Queue Management for assured forwarding traffic in Differentiated Services network

Congestion control mechanism such as random early detect (RED) allows more efficient usage of network resources. RED uses static thresholds (high and low) in combating congestion. However, as network becomes more dynamic with the introduction of multimedia and real time application, this ldquostaticrdquo approach becomes inefficient. This paper proposed a dynamic RED mechanism, namely, fuzzy active queue management (FuzAQM). FuzAQM monitors the condition of a network in real time and changes its RED parameters based on the congestion level using fuzzy control. FuzAQM is implemented and tested using NS2 network simulator. The simulation results showed that the proposed mechanism improves the total network throughput. FuzAQM also ensures a fairer treatment of lower priority packets and at the same time maintains the throughput of higher priority packets in the network.

A semantic-syntax model for XML query construction

Purpose When accessing structured contents in XML form, information requests are formulated in the form of special query languages such as NEXI, Xquery, etc. However, it is not easy for end users to compose such information requests using these special queries because of their complexities. Hence, the purpose of this paper is to automate the construction of such queries from common query like keywords or form-based queries. Design/methodology/approach In this paper, the authors address the problem of constructing queries for XML retrieval by proposing a semantic-syntax query model that can be used to construct different types of structured queries. First, a generic query structure known as semantic query structure is designed to store query contents given by user. Then, generation of a target language is carried out by mapping the contents in semantic query structure to query syntax templates stored in knowledge base. Findings Evaluations were carried out based on how well information needs are captured and transformed into a target query language. In summary, the proposed model is able to express information needs specified using query like NEXI. Xquery records a lower percentage because of its language complexity. The authors also achieve satisfactory query construction rate with an example-based method, i.e. 86 per cent (for NEXI IMDB topics) and 87 per cent (NEXI Wiki topics), respectively, compare to benchmark of 78 per cent by Sumita and Iida in language translation. Originality/value The proposed semantic-syntax query model allows flexibility of accommodating new query language by separating the semantic of query from its syntax.

Finding target and constraint concepts for XML query construction

Purpose – This paper aims to focus on automatic selection of two important structural concepts required in an XML query, namely, target and constraint concepts, when given a keywords query. Due to the diversities of concepts used in XML resources, it is not easy to select a correct concept when constructing an XML query. Design/methodology/approach – In this paper, a Context-based Term Weighting model that performs term weighting based on part of documents. Each part represents a specific context, thus offering better capturing of concept and term relationship. For query time analysis, a Query Context Graph and two algorithms, namely, Select Target and Constraint (QC) and Select Target and Constraint (QCAS) are proposed to find the concepts for constructing XML query. Findings – Evaluations were performed using structured document for conference domain. For constraint concept selection, the approach CTX+TW achieved better result than its baseline, NCTX, when search term has ambiguous meanings by using con...

An Intermediate Query Model for Structured Retrieval's Queries Construction

Looking at the amount of structured contents available on the web in recent years, we can be certain that the needs of structured retrieval systems are getting more prominent. In order to access the structured contents, information requests are formulated in the form of query languages supported by the structured retrieval systems. Nevertheless, information requests at this layer cannot be specified directly by end users. Hence, a common solution is to map information needs obtained from the application layer to the query language of a retrieval system automatically. Although rule-based approach can be used to generate query automatically, it is designed for a single target query language, whereas, there are not one but different types of structured queries with different forms of syntax used in a structured retrieval environment. In this paper, we address the problem of constructing structured queries for structured retrieval by proposing an intermediate query model that can be used to construct different types of structured queries. This model allows flexibility of accommodating new query language by separating the semantic of query from its syntax. Firstly, rule-based approach is used to construct a generic form of query known as semantic query structure. Then, generation of query into target language is carried out by matching templates obtained from example-based method. Evaluations were carried out based on how well information needs are captured and transformed into a target query language. In summary, the proposed model is able to express information needs specified using query like NEXI. Xquery records a lower percentage due to its language complexity. We also achieve satisfactory query conversion rate with our example-based method, i.e. 86% (for NEXI IMDB topics) and 87% (NEXI Wiki topics) respectively compare to benchmark of 78% by Sumita & Iida in language translation.

Effect of varied wireless standards and properties towards wireless network bandwidth

IEEE 802.11 provides multiple wireless networking (WLAN) standards with each new standard attempting to improve overall performance whilst remaining backward compatible to older ones. The current practise of setting up WLANs is to use non-overlapping channels and high signal strengths to provide optimum performance for stations in the network. In this paper, we try to show that the common practises may not be enough to ensure the best performance in a WLAN and stations themselves may be responsible for affecting network performance. Preliminary results are obtained are based on experiments executed in a simple test model using the 802.11g standard.