Bi-criteria and tri-criteria analysis to minimize maximum lateness makespan and resource consumption for scheduling a single machine

We analyze two single machine scheduling problems for the case where job processing times are controllable, by allocating continuous and non-renewable resources to the processing operations. The first problem to analyze is constructing the trade-off curve between maximum lateness and total resource consumption; an O(n ²) computational time optimization algorithm was constructed to solve this problem. This algorithm was extended to solve the second problem, which is to construct the trade-off surface between maximum lateness, makespan, and total resource consumption. As part of this algorithm we identify a plane in the 3D field that is formed by the three criteria, which is parallel only to the maximum lateness, and calculate the optimal makespan and total resource consumption as functions of points on this plane. The extended algorithm keeps the same complexity of O(n ²) time. Both algorithms are very robust as they solve the problem for a very large set of resource consumption functions which has to follow only some mild (and commonly acceptable) conditions. Moreover, as far as we know, this is the first research of its kind in the field of multi-objective scheduling to present an algorithm that constructs a 3D trade-off surface.     

Scaling-up of process for production of antibiotic of myxococcus xanthus TA

A process for the production of Myxococcus xanthus TA (M. xanthus TA) antibiotic was scaled-up to bench and pilot plant scales. The process includes the following steps: (a) propagation of M. xanthus TA in cultures of up to 750 litres. After 4 days of growth the maximum antibiotic yield achieved was 24 units/ml supernatant, and the highest titres were obtained at a low oxygen absorption rate of 0.2; (b) processing of the clarified culture supernatant. Two methods were successfully piloted: the chloroform extraction method and the kaolin adsorption method. Both methods were followed by elution with 20% methanol in chloroform. The recoveries of antibiotic activity were 90% and 85% respectively by the two methods. The process described could be used for the large-scale preparation of the novel antibiotic of M. xanthus TA.     

Stokes flow for a stokeslet between two parallel flat plates

Summary Velocity and pressure fields for Stokes flow due to a force singularity of arbitrary orientation and arbitrary distance between two parallel plates are found, using the image technique and a Fourier transform. Two alternative expressions for the solution, one in terms of infinite integrals and the other in terms of infinite series, are given. The infinite series solution is especially suitable for computation purposes being an exponentially decreasing series. From the series the far field behaviour is extracted. It is found that a force singularity parallel to the two planes has a far field behaviour of source and image for the parallel components (a two dimensional source doublet of height-dependent strength) whereas the normal component, and all fields due to a force singularity normal to the planes, die out exponentially. Velocity fields are compared with those of the one plane case. An estimate of the influence of the second wall and when its effect can be disregarded is obtained.     

Optimal due date assignment and resource allocation in a group technology scheduling environment

We study a single machine scheduling problem in which the scheduler determines due dates for different jobs in a group technology environment. In group technology (GT) environment, a partition of the jobs into groups (families) is given and jobs of the same family are required to be processed consecutively. The partition of the jobs into families is done in order to achieve efficiency of high-volume production by exploiting similarities of different products and activities in their production. Since customers of similar jobs may expect that all jobs within the same group will be assigned with the same due date, we suggest an original due date assignment method in which all jobs within a family are restricted to be assigned the same due date, while each family can be assigned a due date without any restriction. The proposed method provides an extension of two earlier methods that appear in the literature, one which includes a single family and the other in which the number of families is identical to the number of jobs. Our objective is to find the job schedule and the due date for each group that minimizes an objective function which includes earliness, tardiness and due date assignment penalties. We also extend the analysis to address the case in which the job processing times are resource dependent. For this case we include the total weighted resource consumption and the makespan penalties to the objective function.     

Fast image and video colorization using chrominance blending.

Colorization, the task of coloring a grayscale image or video, involves assigning from the single dimension of intensity or luminance a quantity that varies in three dimensions, such as red, green, and blue channels. Mapping between intensity and color is, therefore, not unique, and colorization is ambiguous in nature and requires some amount of human interaction or external information. A computationally simple, yet effective, approach of colorization is presented in this paper. The method is fast and it can be conveniently used "on the fly," permitting the user to interactively get the desired results promptly after providing a reduced set of chrominance scribbles. Based on the concepts of luminance-weighted chrominance blending and fast intrinsic distance computations, high-quality colorization results for still images and video are obtained at a fraction of the complexity and computational cost of previously reported techniques. Possible extensions of the algorithm introduced here included the capability of changing the colors of an existing color image or video, as well as changing the underlying luminance, and many other special effects demonstrated here.     

Markov reliability models of fault-tolerant distributed computing systems

A hierachical view of fault-tolerant distributed computers is presented, viewing a distributed computing system as composed of interconnected, interacting, functional modules. Each module, modeled by a directed-state graph, is governed by internal random failure events and counteracting recovery processes, and also by coupling of external random events from other modules. It is shown that, under certain assumptions, the system is governed by a multidimensional Markov process, with non-Markov module processes as components. Mathematical properties of this model are formally analyzed. Performance measures are found from the steady-state distribution and visitation rate of each system and module state. A numerical example is presented exemplifying its practical application. The results are shown to fit very well the actual statistical data collected on an AT&T Bell Laboratories Electronic Switching System.