nur hamidah

Page 1. Ranking and Selecting Integrity Tests in a Distributed Database Ali A. Alwan Universiti Putra Malaysia Department of Computer Science Faculty of Computer Science and Information Technology, 43400 Serdang, Malaysia 0060173546110 alialgobori@yahoo.com ...

Recently, an urgent need for XML access control mechanism over World Wide Web has been felt. Moreover, an efficient dynamic labeling scheme is required in order to eliminate the re-labeling process of existing XML nodes during XML document updating. However, the previous research on access control mechanisms for XML documents has not addressed the issue of integrating access control with a dynamic labeling scheme. In this paper, we propose an XML access control mechanism integrated with EXEL encoding and labeling scheme to eliminate the re-labeling process for updating the well-formed XML documents. The key idea is to regard an authorization as a query condition to be satisfied. Therefore, the benefit of speeding up searching and querying processes is obtained by employing such a labeling scheme in our proposed access control mechanism.

An optical biosensor based on glutamate dehydrogenase (GLDH) immobilized in a chitosan film for the determination of ammonium in water samples is described. The biosensor film was deposited on a glass slide via a spin-coating method. The ammonium was measured based on β-nicotinamide adenine dinucleotide (NADH) oxidation in the presence of α-ketoglutaric acid at a wavelength of 340 nm. The biosensor showed optimum activity at pH 8. The optimum chitosan concentrations and enzyme loading were found to be at 2% (w/v) and 0.08 mg, respectively. Optimum concentrations of NADH and α-ketoglutaric acid both were obtained at 0.15 mM. A linear response of the biosensor was obtained in the ammonium concentration range of 0.005 to 0.5 mM with a detection limit of 0.005 mM. The reproducibility of the biosensor was good, with an observed relative standard deviation of 5.9% (n = 8). The biosensor was found to be stable for at least 1 month when stored dry at 4 °C.

Peer-to-Peer networks attracted a significant amount of interest because of their capacity for resource sharing and content distribution. Content distribution applications allow personal computers to function in a coordinated manner as a distributed storage medium by contributing, searching, and obtaining digital content. Searching in unstructured P2P networks is an important problem, which has received considerable research attention. Acceptable searching techniques must provide large coverage rate, low traffic load, and optimum latency. This paper reviews flooding-based search techniques in unstructured P2P networks. It then analytically compares their coverage rate, and traffic overloads. Our simulation experiments have validated analytical results.

Knowledge Management System (KMS) is widely deployed as organizations acknowledged the importance to manage critical knowledge efficiently in secure manner. More over the community of practice (CoP) benefit the growing of Internet by constructing a collaborative KMS for better communication. However while the excitement of expanding the KMS capabilities, some security issues exist which regard to the restriction of the access permission to knowledge, such as unauthorized access, losing and misusing critical knowledge and about other knowledge processing. Therefore, the paper reviews the criteria of access control model (ACM) because it is a competent security model to overcome the security issues by considering the characteristics of collaborative system. Consequently, this paper formulates a model of collaborative KMS access control. The proposed model can be a guidance to study further the member of ACM family particularly the role based access control (RBAC) towards secure collaborative KMS.

Acid oxidation is one of the purification method which has been used to open up the caps, removing carbonaceous and metal particles impurities, and attaching functional group (carboxylic groups, -COOH) at the opened caps and MWCNT surfaces. Unfortunately, this method can cause the structural damages of MWCNT, cut them into shorter length and reduced their performance. However, it is reported that the structure damage of CNT can be acceptable if it is not exceeding 4% of damages. Several characterization techniques will be used to study the composition of functionalized MWCNT and measuring the percent damages of functionalized MWCNT.

The ``top-down'' approach is used to fabricate Silicon Nanowires using Scanning Electron Microscope (SEM) based Electron Beam Lithography (EBL) method. Silicon Nanowires or one dimensional nanowires are widely recognized as important elements in development of certain advance nanoscale devices. The Silicon Nanowires with line-width of 50 nm are successfully fabricated at our clean room using this approach. The approach used includes SEM based EBL method, followed by size reduction using Inductively Coupled Plasma-Reactive Ion Etching (ICP-RIE). In addition, the diameter and the length of the Silicon Nanowires can be precisely controlled. In this paper, the Silicon Nanowires formation which includes the EBL system and fabrication processes have been reviewed and discussed. High Power Microscope (HPM), SEM and Atomic Force Microscopy (AFM) were used to characterize the Silicon Nanowires.

A tremendous demand of development worldwide has gained interest of Malaysian construction firms to venture into international construction domain. Identifying and analyzing major determinants of the firm's internal and external factors are crucial in order to ease the complexity in global market expansion. This paper identifies the relative importance of the strengths, weaknesses, opportunities and threats (SWOT's) related to the internationalization of Malaysian contractors. Responses were received from thirty one (31) Class A and Grade 7 Malaysian construction firms registered with CIDB Malaysia in 2010. The findings reveal that “good track record”, “specialist expertise” and “international network” were the most influential strength factors for the firms to effectively compete in international market. However, “shortage of financial resources” as well as “material and labor resources” contributed to the weaknesses in exploring international market. The study also reveals that “opening up new market”, “technological advancement” and “beneficiary international agreements” offered huge opportunities in overseas market. Nevertheless, factors such as “bribery in the host country”, “increase of interest rate” and “lack of awareness” were perceived as the threats due to difficulties in dealing with moral problems, financial risks and unfamiliar environment within the host country. Finally, this study is of relevance to Malaysian construction firms as it systematically highlights the internal and external factors those may affect their performance in international market. These findings may assist them to make necessary preparatory works by enhancing the strengths, reducing the weaknesses, seizing the opportunities and facing the threats in international market, as these elements are consistent- y changing.

Building performance evaluations in real local climate are essential to ensure the effectiveness of methods or strategies implemented to achieve the desirable effects or outcomes. A field study using a test building facility was performed to investigate the benefits of conductive ceiling insulation in real climatic conditions of Malaysia. The objectives of the research were to evaluate building thermal energy performance in four indoor environmental conditions: 24-hour natural ventilation (NV), office-hour (daytime) cooling, residential-hour (night-time) cooling, and lastly 24-hour cooling. The benefits were appraised by analyzing the thermal impact and cooling load (CL) savings. Results show that the degree of benefit and penalty are influenced by the indoor environmental conditions. Ceiling insulation reduced daytime thermal impact but led to night-time thermal penalty due to thermal-lag. The effect was more significant in the attic than the living space underneath whereby in NV mode the attic and indoor temperature was reduced by 4.1 °C and 1.7 °C respectively. In the three cooling modes, the temporal and spatial benefits are evident by the cooling load (CL) savings of 3.65% to 16.88%. Therefore, whist it demonstrated adverse night-time impact, the daytime thermal and energy benefits outweigh the penalties.

Recently, specifying access control for XML documents over World Wide Web have been proposed. Most of the proposed models for specifying XML access control only support read privilege. Therefore, offering an access control model considering update operations is a challenging issue in XML access control specification. This paper proposes an XML access control model to specify access authorizations which deal with updating the well-formed XML documents. Also, a formal representation of update operations supported by our proposed model is defined in terms of the different policies which are taken for each update operation.

In recent years, there has been much focus on the design and development of database management systems that incorporate and provide more flexible query operators that return data items which are dominating other data items in all attributes (dimensions). This type of query operations is named preference queries as they prefer one data item over the other data item if and only if it is better in all dimensions and not worse in at least one dimension. Several preference evaluation techniques for preference queries have been proposed including top-k, skyline, top-k dominating, k-dominance, and k-frequency. All of these preference evaluation techniques aimed to find the “best” answer that meet the user preferences. This paper aims to evaluate these five preference evaluation techniques on real application when huge number of dimensions is the main concern. To achieve this, a recipe searching application with maximum number of 60 dimensions has been developed which assists users to identify the most desired recipes that meet their preferences. Two analyses have been performed, where execution time is the measurement used.