Search

Supplier evaluation is a multiple attribute decision-making (MADM) problem involving a mixture of qualitative and quantitative attributes. Some mathematical programming techniques have difficulty in dealing with the qualitative attributes that are not easy to measure but very important in supplier evaluation. Fuzzy set theory is useful whenever variables defining a complex and vague system can neither be quantitatively defined nor assigned very precise measures, but are described by linguistic values. This paper presents a procedure for supplier evaluation by incorporating fuzzy set theory into the evaluation process to handle the qualitative attributes in the problem. A mathematical ranking method is used to convert the qualitative attributes into crisp scores. All the quantitative and qualitative performance measures are normalized and then using the proposed model, data are integrated into a single score to rank suppliers. The model application is demonstrated through two previously reported data sets under lean philosophy. Keywords: fuzzy sets: decision analysis; purchasing

This study presents a formulation that supports decision-making by determining the optimal number of standby suppliers required to respond to supply failure risks. The problem of supply failure is modelled through a standby approach, in which failure is time-dependent. The probabilities of supply interruption, financial loss caused by supply failure, and operating cost of working with suppliers are modelled to yield the expected total cost, which enables organisations to determine the optimal number of suppliers. Two possible modes of substitution failure are considered in the standby model to enhance the analysis. A set of sensitivity analyses are performed for several input parameters to illustrate the model’s behaviour. The analysis provides an optimal sourcing strategy depending on a combination of supply risk, operational cost vs. loss ratio and length of the supply period. The proposed model indicates the benefits of cost savings, unlike other dynamic models that use multiple suppliers simultaneously. [ABSTRACT FROM PUBLISHER]

The resonant Rutherford backscattering approach was employed in analyzing the stoichiometry of cerium oxide films deposited by radio frequency sputtering on MgO and sapphire substrates. Results show that some films exhibit the off-stoichiometry of CeOy with y exceeding 2.0. The off-stoichiometry is attributed to either cerium vacancies or interstitial oxygen atomic impurities.

Ultrahigh vacuum/chemical vapor deposition system (UHV/CVD) facilitated the growth of high quality Si/Si(1-x)Ge(x) superlattices with 1.5 nanometer thin layers. X-ray diffraction and transmission electron microscopy were used to analyze the crystalline quality.

The shape optimization of structures method using simulated biological growth simulates adaptive shapes assumed by biological structures during growth and atrophy. These simulated biological growth approaches are efficient, and the MSC/NASTRAN finite element program is used for finite element studies. The capability of these approaches is enhanced by improvements in design procedures.

The success of a virtual organisation's (VO) operations is vitally dependent on interoperability and close collaboration between allied organisations and enterprises. This paper proposes a semantic web rule-based knowledge system applied to collaboration moderator service (CMS) to enable semantic integration of heterogeneous data for the moderation of shared knowledge among cooperative VOs. The proposed approach also shows how the new generation of the CMS supports collaborative working by: enhancing interoperability across different enterprise information systems, monitoring the activities of partners within the collaboration to identify opportunities for enhanced collaboration and raising awareness of potential misunderstandings or conflicts between partner strategies or decisions. Therefore, the semantic knowledge systems of CMS can function on a platform that supports interoperability and collaborative activities within VOs. A case study is conducted to illustrate the feasibility of the proposed model and the test results confirm its suitability. [ABSTRACT FROM AUTHOR]

Ultrahigh vacuum chemical vapor deposition system helps grown unipolar Si/SiGe heterojunction (HJ) diode. Examination of the I-V characteristics of the Si/SiGe HJ diodes suggests thermionic emission as the carrier transport model. Activation analysis of the saturation current helps determine the barrier heights and Richardson constants of the HJs. Increase in the thickness of the SiGe strained layer above the critical thickness leads to decrease in the barrier height.

The evolution of vacancy ordering structures in epitaxial YbSi(sub 2 - x) thin films on both (111) and (001)Si has been studied by transmission electron microscopy (TEM). The vacancy ordering structures are expected to exert a strong influence on the physical properties of epitaxial rare-earth silicide nanowires grown on (001)Si.

Presents a study which reported on the observation of persistent photoconductivity (PPC) effect in SiGe/Si quantum wells. Methodology used to conduct the study; Detection of infrared radiation using a p-type SiGe/Si quantum well; Results and discussion on the study.