• Industrial Engineering and Management Systems
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• v.14 no.3
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• pp.289-298
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• 2015

This paper analyses the best batch formations for order picking throughput in narrow-aisle order picking systems. Our analytical comparison finds that a high pick density variation leads to a heavy picker blocking. Simulation experiments show that a distance-based batching algorithm reduces picker blocking by decreasing the number of aisles visited and stabilizing the variation in number of picks per aisle by packing orders tightly, and that the solution quality and mechanism for determining the batch size dictated by the sorting strategy causes varying amounts of blocking. We conclude that combining a distance-based batching method with an appropriate batch sizing strategy will reduce picker blocking and shorten travel in narrow-aisle picking systems.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.4
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• pp.107-118
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• 2007

A single-server queueing model with infinite buffer and batch arrival of customers is considered. In contrast to the standard batch arrival when a whole batch arrives into the system at one epoch, we assume that the customers of an accepted batch arrive one-by one in exponentially distributed times. Service time is exponentially distributed. Flow of batches is the stationary Poisson arrival process. Batch size distribution is geometric. The number of batches, which can be admitted into the system simultaneously, is subject of control. Analysis of the joint distribution of the number batches and customers in the system and sojourn time distribution is implemented by means of the matrix technique and method of catastrophes. Effect of control on the main performance measures of the system is demonstrated numerically.

• Progress in Superconductivity and Cryogenics
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• v.8 no.1
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• pp.23-25
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• 2006

Optimization of process variables, including oxygen and water partial pressure and also an nesting temperature, was performed in batch-type process to fabricate YBCO films on LaAlO3 single crystal. In this work, YBCO oxide powder was used as a starting precursor for metal-organic deposition(MOD)method. The precursor films were fabricated in batch furnace and they were converted to the epitaxial YBCO films at the same furnace with varying the process variables. The oxygen partial pressure was varied from 100ppm to 2000ppm and the water partial pressure from 1.2% to 12.2%. The window for optimal P(O2) was narrow about 700ppm for batch-type process. YBCO films in bathc-thype MOD process were optimized at 740-770oC and P(H2O) of 2.3%-7.3%.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.425-434
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• 2006

The operability and productivity of continuous processes, especially in petrochemical industries have made remarkable improvement during the past twenty years through advanced process control (APC) typified by model-based predictive control. On the other hand, APC have not been actively practiced in industrial batch processes typified by batch polymerization reactors. Perhaps the main cause for this has been the lack of reliable batch process APC techniques that can overcome the unique problems in industrial batch processes. Recently, some noteworthy progress is being made in this area. New high-performance batch process control techniques that can accommodate and also overcome the unique problems of industrial batch processes have been proposed on the basis of iterative learning control (ILC). In this review paper, recent advancement in the batch process APC techniques are presented, with a particular focus on the variations of the so called Q-ILC method, with the hope that they are widely practiced in different industrial batch processes and enhance their operations.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.2
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• pp.124-129
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• 1991

A mass balance method which measures directly both the sorbed pesticide and equilibrium solution concentration was compared with the batch method in a hypothetical experiment to determine the precision of sorption measurement. The mass balance method was shown to improve precision of sorption measurement. The two methods were also tested experimentally on the Wahiawa soil, 0-20, 40-60 and 100-120 cm, and Salinas soil, 0-15 and 115-130 cm. The mass balance method greatly improved precision of sorption measurement on the deep Wahiawa subsoil having the lowest sorption. The coefficient of variation (CV) for $K_d$ measurement was 20.3% for the batch method and 8.4% for the mass balance method. For other soil samples tested, precision of the batch method was relatively high but was still improved by the mass balance method.

• Journal of the Korean Data and Information Science Society
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• v.28 no.6
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• pp.1245-1255
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• 2017

The online learning is a process of obtaining the solution for a given objective function where the data is accumulated in real time or in batch units. The stochastic gradient descent method is one of the most widely used for the online learning. This method is not only easy to implement, but also has good properties of the solution under the assumption that the generating model of data is homogeneous. However, the stochastic gradient method could severely mislead the online-learning when the homogeneity is actually violated. We assume that there are two heterogeneous generating models in the observation, and propose the a new stochastic gradient method that mitigate the problem of the heterogeneous models. We introduce a robust mini-batch optimization method using statistical tests and investigate the convergence radius of the solution in the proposed method. Moreover, the theoretical results are confirmed by the numerical simulations.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1250-1256
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• 2011

In this study, Bacillus licheniformis cells were immobilized by entrapment in calcium alginate beads and were used for production of alkaline protease by repeated batch process. In order to increase the stability of the beads, the immobilization procedure was optimized by statistical full factorial method, by which three factors including alginate type, calcium chloride concentration, and agitation speed were studied. Optimization of the enzyme production medium, by the Taguchi method, was also studied. The obtained results showed that optimization of the cell immobilization procedure and medium constituents significantly enhanced the production of alkaline protease. In comparison with the free-cell culture in pre-optimized medium, about 7.3-fold higher productivity was resulted after optimization of the overall procedure. Repeated batch mode of operation, using optimized conditions, resulted in continuous production of the alkaline protease for 13 batches in 19 days.

• Journal of the Korean Operations Research and Management Science Society
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• v.25 no.1
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• pp.37-50
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• 2000

We are concerned with estimating the average performance of a re-entrant line with single-job machines and batch machines. The system has multiclass jobs, which will be processed in predetermined routes. An analytical approach may be intractable since the system would not be modeled by product form queueing networks due to the inclusion of batch machines and the consideraton of multiclass jobs which have different processing times. We propose an approximation method based on the Mean Value Analysis(MVA). Our method obtains the mean walting time in each buffer of a workstation and the mean cycle time using the MVA and heuristics. numerical experiments show that the errors of our method are within 5% compared with simulation.

• Communications of the Korean Mathematical Society
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• v.32 no.2
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• pp.425-433
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• 2017

This paper is concerned with the analysis of the busy period distribution in a batch arrival $M^X/G/1$ retrial queue. The expression for the Laplace-Stieltjes transform of the length of the busy period is well known, but from this expression we cannot compute the moments of the length of the busy period by direct differentiation. This paper provides a direct method of calculation for the first and second moments of the length of the busy period.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.749-753
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• 1993

It is very difficult to control batch reactor with conventional linear controller due to its severe nonlinearity. To control the nonlinearity of batch reactor, we applied with relay feedback method and SOAS. The SOAS can be designed to work quite well, but it requires engineering effect and some knowledge about the process in order to get a satisfactory performance of the closed loop system For the applications to more reliable, further studies on robustness in various situations and process noises and would be required.