Showing papers by "Universiti Teknologi Malaysia published in 2003"

Information hiding using steganography

Abstract: Due to advances in ICT, most information is kept electronically. Consequently, the security of information has become a fundamental issue. Besides cryptography, steganography can be employed to secure information. Steganography is a technique of hiding information in digital media. In contrast to cryptography, the message or encrypted message is embedded in a digital host before passing it through the network, thus the existence of the message is unknown. Besides hiding data for confidentiality, this approach of information hiding can be extended to copyright protection for digital media: audio, video, and images.

Improved SPC chart pattern recognition using statistical features

Abstract: Increasingly rapid changes and highly precise manufacturing environments require timely monitoring and intervention when deemed necessary. Traditional Statistical Process Control (SPC) charting, a popular monitoring and diagnosis tool, is being improved to be more sensitive to small changes and to include more intelligence to handle dynamic process information. Artificial neural network-based SPC chart pattern recognition schemes have been introduced by several researchers. These schemes need further improvement in terms of generalization and recognition performance. One possible approach is through improvement in data representation using features extracted from raw data. Most of the previous work in intelligent SPC used raw data as input vector representation. The literature reports limited work dealing with features, but it lacks extensive comparative studies to assess the relative performance between the two approaches. The objective of this study was to evaluate the relative performance of a feature-...

A survey of TQM practices in the Malaysian electrical and electronic industry

Abstract: Total quality management (TQM) is one of the key approaches towards realizing the goal of meeting customer satistaction. Besides efforts for quality improvement by large companies, many small and medium-sized enterprises (SMEs) have also pursued their quality improvement effort, but mostly through the ISO 9000 certification route. Few of these SMEs have actually implemented a total approach using the TQM philosophy. This paper relates to a survey conducted to investigate the level of practice on TQM elements and to find the most critical factors perceived by the SMEs. A questionnaire was sent to 248 companies in the electrical and electronics sector in Malaysia, which resulted in a response rate of 24.2%. Attempts at finding significant differences between small and large companies' quality practices were made and revealed that there was a significant difference between the TQM practices of large and small companies. Management leadership, continuous improvement system and education and training proved to...

Review on the development of defect-free and ultrathin-skinned asymmetric membranes for gas separation through manipulation of phase inversion and rheological factors

Abstract: Development of high-performance asymmetric membranes is a major breakthrough in membrane technology. A comprehensive study on original concepts and new advances in membrane formation process is necessary to generate defect-free and ultrathin-skinned asymmetric membranes with superior performance for gas separation process. Correlation of rheological factors with primary-phase inversion process is a novel approach in membrane research that provides a potential platform to improve membrane performance. The former controls general morphology of membrane, whereas the latter further affects molecular orientation in membrane. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 442–451, 2003

The need for a new product development framework for engineer‐to‐order products

Abstract: New product development (NPD) is the cornerstone of manufacturing companies. An engineer‐to‐order (ETO) company can achieve its business objectives by reducing design iterations and rework, recognizing customer’s requirements up‐front and building quality into design and manufacturing. This paper discusses differences between ETO and make‐to‐stock (MTS) companies and justifies the need for a separate framework for ETO in NPD. Four frameworks from published literature were analyzed and it was found that the frameworks were not suitable for ETO companies due to the differences in operations and product design activities. This paper proposes a set of requirements for establishing a design and manufacture framework specifically for ETO companies. The framework can aid design and manufacturing engineers to plan their work to include customers, suppliers, consultants, contractors and manufacturing concern during the design stage. The framework requirements can serve as a foundation of further work to be carried out in this area.

Mixed convection boundary‐layer flow from a horizontal circular cylinder in micropolar fluids: case of constant wall temperature

Abstract: The laminar mixed convection boundary‐layer flow of a micropolar fluid past a horizontal circular cylinder in a stream flowing vertically upwards has been studied in both cases of a heated and cooled cylinder. The solutions for the flow and heat transfer characteristics are evaluated numerically for different parameters, such as the mixed convection parameter λ, the material parameter K (vortex viscosity parameter) and the Prandtl number Pr=1 and 6.8, respectively. It is found, as for the case of a Newtonian fluid considered for Pr=1, that heating the cylinder delays separation and can, if the cylinder is warm enough, suppress it completely. Cooling the cylinder, on the other side, brings the separation point nearer to the lower stagnation point and for sufficiently cold cylinder there will not be a boundary‐layer on the cylinder. This model problem may solve industrial problems with processing of polymeric liquids, lubricants and molten plastics.

Enhanced chaotic image encryption algorithm based on Baker's map

Abstract: Imaging has gained importance due to the improvements of performances in computer speed, media storage and network bandwidth. Along with this advancement, the fundamental issue of image security has become a major concern and because of this reason, research in image confidentiality has gained popularity amongst security experts. This paper discusses an alternative chaotic image encryption based on Baker's map. This enhanced symmetric-key algorithm can support a variable-size image as opposed to the algorithm which is mainly based on Baker's map that requires only square image for encryption. In addition, the algorithm also includes other functions such as password binding and pixel shifting to further strengthen the security of the cipher image. The algorithm also supports two modes of operation namely EBC and CBC. The number of iterations to be performed can vary depending on the security level required by the user. The paper also includes an example of image encryption. From the analysis done, it shows that the security level is high even though keys that are found to be weak keys for Baker's map algorithm are being used in the algorithm.

Case study method for new product development in engineer‐to‐order organizations

Abstract: The case study method has been widely used as a research instrument for data collection to build theory. Reports on the use of case study method for new product development (NPD) in an engineer‐to‐order (ETO) organization. Discusses previous work on NPD in the literature in order to determine the knowledge gap that exists. Discovers that NPD work in an ETO organization is lacking despite its importance. Proposes a case study method as a tool to bridge this gap. Explains and justifies the reasons for choosing the case study method. Also describes case study design with the case study protocol. Then discusses the execution of the case study, method of analysis and the limitations of case study research. The findings will assist researchers who are interested in pursuing future research work in this area.

Hazards at construction sites

Abstract: Statistic has shown that the number of fatality and permanent disablement cases due to accident at the Malaysia construction sites is one of the highest as compared to the other sector. Even though the number of industrial accidents decreasing but the benefits paid to the accidents victims are ever increasing. Hence, there is an urgent need to mitigate this problem. There are three basic steps that should be taken namely identifying the hazard, assessing the risk and controlling the risk to ensure a safe and conducive working condition. Implementation of effective hazards control methods may require different approaches due to changing of working environment at the construction sites. Latest technology employed at site had wiped out traditional method of construction and consequently introduce new types of hazard to the industry. Therefore, this paper is intended to identify and highlights the hazards that are most commonly found at our construction sites today. The data collection was being carried out through site investigation using a structured questionnaires forms regarding hazards in construction. The sites vary from infrastructure works, high rise building, housing development, industry building and institutional building. The study determine twelve (12) major groups of hazards in relation to works at construction sites such as power access equipment, ladder, roof work, manual handling, plant and machinery, excavation, fire and emergency, hazardous substances, noise, protective clothing and protection to public. The study was conducted on 140 construction sites and the results showed that the most common hazards for the project around the study area are associated with the protective clothing, noise and fire and emergency.

Logging History and Its Impact on Forest Structure and Species Composition in the Pasoh Forest Reserve — Implications for the Sustainable Management of Natural Resources and Landscapes

Abstract: A part of the Pasoh Forest Reserve (Pasoh FR) was once logged under a logging regime called the Malayan Uniform System (MUS) in the 1950s. The core area of the reserve is a residual unlogged (primary) forest that shows the typical structure and species composition of lowland dipterocarp forest; the logged area of the reserve is also a relict area of regenerating lowland forest. In this chapter, we review and summarize previous studies of logging impacts on the forest structure and total aboveground biomass by comparing the primary and regenerating forests of this reserve. We also studied landscape changes in the Pasoh Forest Region in order to discuss the relationship between logging history in this region and its impacts on the forest. From a chronological analysis of the changes in land use in this region, we found that ca. 50% of the forested area had been converted to either oil palm or rubber plantations from 1971 to 1996. Almost all of the lowland dipterocarp forest that had developed in the flat and alluvial topography had vanished from this region, except in the Pasoh FR. Thus, very little area was left to be managed by the MUS approach, which was originally designed for extracting timber with a longer logging cycle (>70 years) in this type of forest. By examining the canopy and stand structure and the species composition of these forests, we found a greater density of semi-medium (6-10 cm in diameter) and medium trees (10–30 cm), a higher density of canopy-forming trees with relatively smaller crowns, and a higher density of non-commercial canopy-forming trees in the regenerating forest. These findings suggest that the MUS was incompletely implemented, since this system originally aimed to encourage the development of a uniform forest structure with a large number of sound commercial timber trees by removing noncommercial trees. Owing to the high density of canopy-forming trees, which probably resulted from incomplete post-logging thinning and vegetation-control operations, structural development was delayed in the regenerating forest. In addition, the species composition and the distribution of wildlife in the regenerating forest differed from those in the primary forest. We also found that the total aboveground biomass in the regenerating forest had not fully recovered to the level in the primary forest even 40 years after logging. We suggest that “follow-up operations” should be undertaken, with a special concern for encouraging the structural development of the stand, which we consider to be crucial for ecologically sustainable management.

Characteristics of Energy Exchange and Surface Conductance of a Tropical Rain Forest in Peninsular Malaysia

Abstract: Energy exchange above tropical rain forest was studied using micro-meteorological monitoring from a 52 m tower established in the Pasoh Forest Reserve (Pasoh FR) in Peninsular Malaysia. The meteorological conditions were comparatively drier during the first half of the year and wetter toward the end of the year due to the seasonal variation of rainfall. The five-year observational period from 1995 to 1999 included a low rainfall duration due to the El Nino from 1997 to 1998. The latent heat flux estimated by the Bowen ratio method occupied a dominant portion of the energy exchange even in the driest condition in early 1998. Although evapotranspiration from the dry canopy tended to be smaller in this period than in a wet period during the end of 1998, the surface conductance estimated using the Penman Monteith Equation was consistently controlled by the same function of solar radiation and specific humidity deficit. This suggests the evaporation did not suffer from severe stress of soil water even in the driest condition.

Selective reduction of NOx with C3H6 over Cu and Cr promoted CeO2 catalysts

Abstract: The Cu/CeO2 and Cu/Cr/CeO2 catalysts synthesized using the impregnation method were employed to investigate the selective reduction of NOx with C3H6 at 673.15 K and 1 atm. The activity of CeO2 was greatly induced by loading 4 wt.% of Cu onto the bare support. The presence of C3H6 was a crucial factor for elevating the NOx conversion under lean conditions. The modification of the optimal Cu(4)/CeO2 catalyst with 3 wt.% of Cr steadily improved the performance of the catalysts. Both the optimal Cu(4)/CeO2 and Cu(4)/Cr(3)/CeO2 catalysts were characterized using XRD, SEM and TPR-H2. The co-existence of CuO, Cr2O3 and CuCr2O4 was believed to grant the promising performance of the Cu(4)/Cr(3)/CeO2 catalyst in SCR-HC under net oxidizing conditions.

Application of quality function deployment (QFD) method for pultrusion machine design planning

Abstract: Machine design and manufacture is the key to the advancement of manufacturing industry. Before any machine can be designed, it is important to establish requirements of the machine. Identifies quality function deployment (QFD) as one of the tools that can be used to identify customer needs and link the needs to product design. By bringing forward customers’ requirements into the design process, design rework and unnecessary iteration between design and manufacture can be reduced. In this project, QFD for a pultrusion machine design has been chosen as a case study. QFD was applied at the front end of the design process. The QFD process started with identifying the customers and determining their needs. These needs were translated into engineering requirements which were then used to formulate general specifications of the machine. A step by step approach was introduced to make the QFD process more manageable. Reports on the first phase of a research project in which QFD was used to capture all vital information from the customers and translated that into engineering requirements.

Routing protocols in wireless mobile ad hoc network - a review

Abstract: This paper presents a review of current routing protocols used in mobile ad hoc network (MANET). Routing is a challenging issue in ad hoc network since nodes are mobile and the topology of the networks is ever changing. Besides, all nodes need to communicate via wireless infrastructure. Routing metrics used such as shortest path, link quality, power conservation and position location (PL) will reduce route discovery time and also message update cost.