Analysis of flexibility with rationing for a mix of manufacturing facilities

A major competitive advantage of a flexible manufacturing facility is its ability to cope with uncertainties in demand. At a strategic level, capacity-size decisions for a mix of flexible facilities (each not necessarily producing the same combination of products) are made based on aggregates of product types. Such an approach overlooks possible capacity-devouring by some products, arising at the operational level, when the aggregate demand for the period exceeds the available capacity. A rationing policy is required to ensure that the available aggregate capacity of the facilities is shared equitably. In this article, it is shown that such a rationing policy has an impact on the required capacity size and, therefore, must be integrated with the decisions at the strategic level. Several properties indicating the relative preferences of certain facility strategies are also established.     

Efficient Transition Fault ATPG Algorithms Based on Stuck-At Test Vectors

This paper proposes novel algorithms for computing test patterns for transition faults in combinational circuits and fully scanned sequential circuits. The algorithms are based on the principle that s@ vectors can be effectively used to construct good quality transition test sets. Several algorithms are discussed. Experimental results obtained using the new algorithms show that there is a 20% reduction in test set size, test data volume and test application time compared to a state-of-the-art native transition test ATPG tool, without any reduction in fault coverage. Other benefits of our approach, viz. productivity improvement, constraint handling and design data compression are highlighted.     

Algorithms for I DDQ measurement based diagnosis of bridging faults

In the absence of information about the layout one is left with no alternative but to consider all bridging faults. An algorithm for diagnosis of a subset of such faults, viz. single two line bridging faults in static CMOS combinational circuits is presented. This algorithm uses results from I _DDQ measurement based testing.Unlike known diagnosis algorithms, this algorithm does not use fault dictionaries, it uses only logic simulation and uses no fault simulation. It also uses SOPS, a novel representation of subsets of two-line bridging faults resulting in an efficient algorithm.In spite of the large number of faults that we consider, our experimental results point to the computational feasibility of I _DDQ Measurement based diagnosis of single two line bridging faults. It also shows the effectiveness of reducing the set of possible faults using I _DDQ measurements.A preliminary version of this work was presented at the 29th ACM/IEEE Design Automation Conference, 1992.Research Partially Supported by NSF Grant No. MIP-9102509.This work was performed when the author was with the Dept. of Computer Science, State University of New York at Buffalo.     

Line Balancing With Task Learning Effects

In this paper we show how the learning effects of the individual tasks can be incorporated in the initial design of the stations so that the system may not experience large idle times. We account for the learning effects in assigning tasks to stations by linking the task assignment to the formation of dynamic (in time) bottleneck stations. The station design problem is modeled as a dynamic recursive optimization with computational complexity of O( M²N), where Mis the number of tasks and Nthe number of production units. Using a computer simulation for a system designed by using our task assignment procedure, we compare the system idle times with/without ignoring the learning effects.     

A Hierarchical Data Structure for Representing the Spatial Decomposition of 3-D Objects

The polytree, a generalization of the octree data structure, retains most of the desirable features of the octree structure while offering several advantages.     

Influence of hydrofuramide on network structure and kinetics of thiuram vulcanization

The influence of hydrofuramide (a reaction product of furfural and ammonia) on the network structure and overall kinetics of thiuram vulcanization of natural rubber is reported. The nature of the network structure of the thiuram vulcanizates in the presence and absence of hydrofuramide was determined using triphenyl phosphine (Ph₃P) as a chemical probe. The presence of hydrofuramide produces structural complexity of the vulcanizate. The overall kinetics of thiuram vulcanization follows a first-order-rate law in the presence as well as in the absence of hydrofuramide. The rate constant increases while the energy of activation decreases in the presence of hydrofuramide.     

Delta virus infection in cirrhotics in a north Indian hospital

Forty patients of HBV related cirrhosis of the liver were studied for the presence of delta infection and subsequently the clinical features, course and outcome of these delta infected cases was compared with those of delta uninfected cases. Out of 40 patients studied, only four patients (10%) were reactive for anti-delta antibodies. The incidence of delta infection was common in the younger age group (31.25 +/- 4.78 years) as compared to the older age group (48 +/- 7.25 years) at p < 0.001. Hepatic Encephalopathy was seen in only 13.88% of delta negative patients as compared to 75% of delta infected patients (p < 0.05). During follow up period of 1 year, 75% of patients died in the delta virus infected group as compared to 22.22% in the delta negative group. The mortality was significantly higher in Child's class C (P < 0.01). So delta virus infection is associated with a more severe course of illness and a poorer prognosis in HBV related cirrhotics.     

The influence of gum on the crystalline structure in ramie fiber

The fine structure of decorticated and degummed ramie fibers was studied by x-ray and optical methods. It has been found that while crystallinity increases, crystallite orientation deteriorates with gradual removal of gum. Optical orientation falls at a more rapid rate, indicating that the major part of the gum resides in the amorphous regions and these regions are more sensitive to the process of extraction of gum.     

A Programmable Phased Array with Time-Delay Units and its Applications

In this paper, a phased array antenna schematic using true time delays is proposed and suitable time-delays are inserted by switching ON/OFF the RF switches. Using this concept, one can generate SUM pattern, DIFFERENCE pattern, as well as a combination of these two. It is shown that SUM-DIFFERENCE pattern has interesting applications in radar, namely, calibration of beam pointing accuracy and blind speed elimination in a delay line cancellation method. The proposed method can also be formatted to requirements of conical scan as well as shaped beam generation. The proposed method is validated using existing knowledge.