Open Time Interval Research Articles

Two-machine flow shop scheduling with an operator non-availability period to minimize makespan

In this paper, we consider the two-machine flow shop scheduling with an operator non-availability period in the first stage to minimize makespan, where the operator non-availability period is an open time interval in which a job can neither start nor complete. We first prove that the problem is NP-hard, even if the length of the operator non-availability period is no more than the processing time of any job on the first machine. Then we show that Johnson’s rule is a 2-approximation algorithm and the bound is tight. Moreover, a better tight 3/2-approximation algorithm is provided.

Single-machine scheduling with operator non-availability to minimize total weighted completion time

In this paper, we investigate the single-machine scheduling with an operator non-availability period to minimize total weighted completion time, where the operator non-availability period is an open time interval in which no job can be started or be completed. For this problem, we present a pseudo-polynomial-time algorithm and a fully polynomial-time approximation scheme. Our results address two open problems proposed in Chen et al. [2].

Optimizing inkjet printing process to fabricate thick ceramic coatings

This article describes the use of Taguchi optimization and ANOVA techniques on inkjet printing process to determine optimal parameters for fabrication of thick ceramic coatings over glass substrates. Stable nanoparticle suspensions are synthesized through high energy milling of precursor powders with adequate quantities of binder and suspending solvent. Most often, inkjet printing process is being used for developing fine and thin layers (<10µm). However, an attempt is made to fabricate thick ceramic films by varying only IJP process parameters and without multiple layer deposition, thereby reducing efforts in ink synthesis and processing time of coated substrates. Three parameters of IJP were varied for developing a model that was used for precisely predicting the printed layer thickness under varying process parameters. ANOVA technique showed that open time interval in combination with nano particle concentration in the ink could potentially lead to thick coatings. The higher volume % of solvent in the diluted suspension ink under the influence of substrate heating contributed significantly to coffee stain effect with irregular surface coatings. However, increasing the concentration of nanoparticles in the diluted ink resulted in substantial improvement in thickness of the layer with simultaneous control of coating defects.

Experimental Studies on Compressed-Air Energy Storage Power Generation and Evaluation on its Power Quality

To enhance the efficiency of wind power generation and power generation capacity of the energy storage system, a compressed-air energy storage (CAES) power generation system test platform is developed to study load shifting capacity and power generation quality of the system. The results show that the variation of energy storage system’s loaded and unloaded voltage-pressure is basically identical. Meanwhile, a comparative study on the load shifting capacity of the CAES power generation system is presented. We come to the conclusion that when the open time interval is 30s, the system has strong filtering capacity, with the absolute value of the maximum voltage deviation is 7.09%, indicating that the quality of the CAES power generation system can fully meet the requirements of the power network. The research findings will be beneficial to further enhance the development of the wind power generation technology and will provide a theoretical reference for application and promotion of the CAES generation. The purpose of this study is to provide an overview about the CAES power generation through addressing recent patents and scholarly articles on this subject.

Complexity and approximation of single machine scheduling with an operator non-availability period to minimize total completion time

This paper considers the single machine scheduling problem with an operator non-availability period. The operator non-availability period is an open time interval in which a job may neither start nor complete. The objective is to minimize the total completion time. We prove that the problem is NP-hard, even if the length of the operator non-availability period is smaller than the processing time of any job. We also present an algorithm with a tight worst-case ratio of 20/17.

On probabilistic timed automata

We propose a model of probabilistic timed automaton which substitutes for the non-determinism of an ordinary timed automaton, a new one (directly drawn from Markov decision processes) by means of actions which provide a probabilistic distribution over transitions. Using Büchi acceptance conditions, timed automata can refer timing properties as “during every open time interval of length 1 at least one message is delivered”. A policy is a mechanism which solves the non-determinism by choosing for each finite run an action and the time moment of the next transition step implied by this action. We prove that, given a probabilistic timed automaton A , there exists a Markov (memoryless) policy which maximizes the probability p of the set of accepting runs realized by this policy. This policy as well as the maximal value of p are computable in polytime in the size of the region automaton of A . This result provides an algorithm of model-checking for properties like “there is a policy which realizes a correct behavior of the system with probability at least p”.

Bus Transfer Tests on 2,300-Volt Station Auxiliary System

Transfer tests were made of one auxiliary bus section in a large power station from one source to another source. The two sources, one an auxiliary generator and the other a service transformer, were not paralleled during the transfer operation. The optimum open time interval was determined and inrush currents, voltage changes, and some power measurements were made on the combined bus load and on several individual motors. Successful transfers were made at time intervals up to about 150 cycles. The motors, the auxiliary generator, and the station boilers operated satisfactorily for all tests.