Modeling and performance analysis of shuttle-based compact storage systems under parallel processing policy

Short response time for order processing is important for modern warehouses, which can be potentially achieved by adopting appropriate processing policy. The parallel processing policy have advantages in improving performance of many autonomous storage and retrieval systems. However, researchers tend to assume a sequential processing policy managing the movement of independent resources in shuttle-based compact storage systems. This paper models and analyses a single-tier of specialized shuttle-based compact storage systems under parallel processing policy. The system is modeled as a semi-open queueing network with class switching and the parallel movement of shuttles and the transfer car is modeled using a fork-join queueing network. The analytical model is validated against simulations and the results show our model can accurately estimate the system performance. Numerical experiments and a real case are carried out to compare the performance of parallel and sequential processing policies. The results suggest a critical transaction arrival rate and depth/width ratio, below which the sequential processing policy outperforms the parallel processing policy. However, the advantage of sequential processing policy is decreasing with the increasing of shuttle number, transaction arrival rate and depth/width ratio. The results also suggest an optimal depth/width ratio with a value of 1.75 for minimizing the expected throughput time in the real system. Given the current system configurations, the parallel processing policy should be considered when the number of shuttles is larger than 2 or the transaction arrival rate is larger than 24 per hour.

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Analysis of semi-open queueing networks using lost customers approximation with an application to robotic mobile fulfilment systems

OR Spectrum ◽

10.1007/s00291-021-00662-9 ◽

2021 ◽

Author(s):

Sonja Otten ◽

Ruslan Krenzler ◽

Lin Xie ◽

Hans Daduna ◽

Karsten Kruse

Keyword(s):

Queueing Networks ◽

Queueing Network ◽

Arrival Rate ◽

Second Step ◽

Original Network ◽

Theoretical Methods ◽

Solution Approach ◽

Open Queueing Networks ◽

Open Queueing Network ◽

Storage Area

AbstractWe consider a semi-open queueing network (SOQN), where one resource from a resource pool is needed to serve a customer. If on arrival of a customer some resource is available, the resource is forwarded to an inner network to complete the customer’s order. If no resource is available, the new customer waits in an external queue until one becomes available (“backordering”). When a resource exits the inner network, it is returned to the resource pool. We develop a new solution approach. In a first step we modify the system such that new arrivals are lost if the resource pool is empty (“lost customers”). We adjust the arrival rate of the modified system such that the throughputs in all nodes of the inner network are pairwise identical to those in the original network. Using queueing theoretical methods, in a second step we reduce this inner network to a two-station system including the resource pool. For this two-station systems, we invert the first step and obtain a standard SOQN which can be solved analytically. We apply our results to storage and delivering systems with robotic mobile fulfilment systems (RMFSs). Instead of sending pickers to the storage area to search for the ordered items and pick them, robots carry shelves with ordered items from the storage area to picking stations. We model the RMFS as an SOQN to determine the minimal number of robots.

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Performance measures of parallel tandem open queueing network

International Journal of Pervasive Computing and Communications ◽

10.1108/ijpcc-03-2020-0012 ◽

2020 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Banu Priya ◽

Rajendran P.

Keyword(s):

Performance Analysis ◽

Waiting Time ◽

Queueing Network ◽

Performance Measure ◽

Tandem Queue ◽

Content Type ◽

Average Waiting Time ◽

Open Queueing Network ◽

And Performance ◽

System Average

Purpose The authors consider parallel four-state tandem open queueing network. The queue capacity is infinite. Passenger arrival rate is Poisson distribution and service rate is exponential distribution. The queue is constructed in the form of tandem queue, and each and every queue of tandem queue is single server (M/M/1) queue. In tandem queue, passengers will leave the system once they receive service from both the states. The purpose of this paper is to provide performance analysis for four-state tandem open queue network, and a governing equation is formulated with the help of transition diagram. Using Burke theorem, the authors formulated equation for average number of passenger in the system, average waiting time of passenger in the system, average number of passenger in the queue and average waiting time of passenger in the queue. Design/methodology/approach This paper used Burke’s theorem. Findings In this paper, performance analysis is done for parallel four-state tandem open queueing network and performance measure solved using Burkes theorem formula. K. Sreekanth et al. has done performance analysis for single tandem queue with three states. In this paper, the authors have done performance analysis for two tandem queues parallel with four states. This four-state tandem open queueing network is suitable for real world applications. This paper can extend for more number of service states and multi-server states according to the application, and in such case, the authors have to prove and explain with numerical examples. This analysis is more useful for the applications such as airports, railway stations, bus-stands and banks. Originality/value In this paper, parallel four-state tandem open queueing network and performance measure has been solved using Burke’s theorem formula.

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An Approximate Solution for Semi-Open Queueing Network Model of an Autonomous Vehicle Storage and Retrieval System

IEEE Transactions on Automation Science and Engineering ◽

10.1109/tase.2012.2200676 ◽

2013 ◽

Vol 10 (1) ◽

pp. 205-215 ◽

Cited By ~ 35

Author(s):

Banu Y. Ekren ◽

Sunderesh S. Heragu ◽

Ananth Krishnamurthy ◽

Charles J. Malmborg

Keyword(s):

Approximate Solution ◽

Network Model ◽

Retrieval System ◽

Autonomous Vehicle ◽

Queueing Network ◽

Storage And Retrieval ◽

Open Queueing Network

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Analysis of autonomous vehicle storage and retrieval system by open queueing network

2009 IEEE International Conference on Automation Science and Engineering ◽

10.1109/coase.2009.5234100 ◽

2009 ◽

Cited By ~ 5

Author(s):

Sunderesh S. Heragu ◽

Xiao Cai ◽

Ananth Krishnamurthy ◽

Charles J. Malmborg

Keyword(s):

Retrieval System ◽

Autonomous Vehicle ◽

Queueing Network ◽

Storage And Retrieval ◽

Open Queueing Network

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ANALISIS PERFORMANSI SERVER SISTEM INFORMASI AKADEMIK UNIVERSITAS MERCU BUANA DENGAN OPEN QUEUEING NETWORK

Jurnal Ilmiah FIFO ◽

10.22441/fifo.v7i2.1259 ◽

2015 ◽

Vol 7 (2) ◽

pp. 244

Author(s):

Desi Ramayanti

Keyword(s):

Service Time ◽

Queueing Network ◽

Arrival Rate ◽

Service Demand ◽

Open Queueing Network ◽

Data Error ◽

Resource Service ◽

Time Resource

SIA (Sistem Informasi Akademik) merupakan sebuah sistem informasi penting yang berkaitan dengan nilai yang sudah diperoleh untuk setiap matakuliah yang telah diambil, status dari mahasiswa pada semester terkait, dll. SIA ini akan selalu diakses oleh mahasiswa dan juga dosen di lingkungan UMB, baik pada setiap awal semester, pertengahan semester atau pada akhir semester. SIA merupakan fitur penting yang harus tetap available setiap saat, dan mampu melayani ribuan user dengan baik. Keterlambatan data (delay), kehilangan data (lost) dan kerusakan data (error), harus menjadi point penting dalam sebuah system, karena jika ketiga hal tersebut terjadi, maka nilai informasi akan berkurang atau menjadi tidak berarti lagi, dan hal ini akan sangat merugikan, khususnya kepada mahasiswa sebagai konsumen yang wajib mendapatkan pelayanan terbaik. Maka dikarenakan hal tersebut, maka penulis melakukan penelitian berkaitan dengan performansi SIA saat ini. Dalam penelitian ini, penulis melakukan analisis performansi SIA yang terkait dengan arrival rate resource, service time resource utilisasi resource, Rata-rata jumlah kunjungan ke resource, service demand resourcedan arrival rate maksimum dari server. Dari hasil analisis maka diperoleh kesimpulan bahwa performansi dari server SIA yang ada saat ini kurang maksimum dengan jumlah mahasiswa yang ada. Server Sistem Informasi Akademik saat ini hanya mampu melayani request per detik sebanyak 7.278 request. Sedangkan arrival rate yang ada yaitu 8.88 request per detik, sehingga kemungkinan lost request adalah 21.98%.

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Numerical analysis and performance assessment of metal hydride-based hydrogen storage systems

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2008.08.006 ◽

2008 ◽

Vol 33 (21) ◽

pp. 6178-6187 ◽

Cited By ~ 35

Author(s):

M GAMBINI ◽

M MANNO ◽

M VELLINI

Keyword(s):

Numerical Analysis ◽

Hydrogen Storage ◽

Performance Assessment ◽

Metal Hydride ◽

Storage Systems ◽

And Performance

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Achievement in School in Relation to Simultaneous and Sequential Cognitive Processes among Young Egyptian Students

Perceptual and Motor Skills ◽

10.2466/pms.1997.84.3c.1139 ◽

1997 ◽

Vol 84 (3_suppl) ◽

pp. 1139-1148 ◽

Cited By ~ 5

Author(s):

Fadia Z. Elwan

Keyword(s):

Cognitive Processing ◽

Cognitive Processes ◽

Sequential Analysis ◽

School Achievement ◽

Reading Scores ◽

Sequential Processing ◽

Simultaneous Synthesis ◽

And Performance ◽

The Relationship ◽

Reading Decoding

The present study was designed to examine whether a relationship exists between scores on simultaneous and sequential cognitive processes, on one hand, and performance on the Reading Decoding and Arithmetic subtests of the Kaufman Assessment Battery for Children (K–ABC), on the other hand, using a sample of 170 Egyptian school children in Grades 1, 3, and 5. To examine the differential magnitudes of the relationship between scores for cognitive processing and school achievement a two by two (simultaneous × sequential) analysis of variance was calculated with reading decoding and arithmetic scores as dependent variables. The results indicated that cognitive processing, especially simultaneous synthesis, is related to arithmetic as well as decoding during reading. Scores on sequential processing were not significantly related to scores for decoding reading and may not be important as simultaneous processing for mathematical skills. The findings were interpreted in the context of the Arabic orthographic system and in view of the nature of the cognitive and mathematical tasks employed in this study.

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Mixing Characteristics of a Two-Phase Flow (Gas-Liquid) Microchannel Mixer

ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels, Volume 2 ◽

10.1115/icnmm2011-58238 ◽

2011 ◽

Author(s):

Tarek Abdel-Salam ◽

Srikanth Pidugu

Keyword(s):

Reynolds Number ◽

Two Phase Flow ◽

Bubble Formation ◽

Width Ratio ◽

Phase Flow ◽

Two Phase ◽

Bubble Generation ◽

Air Bubble ◽

And Performance ◽

Actual Shape

Multiphase phase flows occur in many engineering and bio-medical applications. Bubble formation in microchannels can be beneficial or harmful depending upon their influence on the operation and performance of microfludic devices. Potential uses of bubble generation found in many applications such as microreactors, micropump, and micromixers. In the present work the flow and mixing process in a passive microchannel mixer were numerically investigated. Effects of velocity, and inlet width ratio (Dgas/Dliquid) on the two phase flow were studied. Numerical results are obtained for 2-dimensional and 3-dimesional cases with a finite volume CFD code and using structured grids. Different liquid-gas Reynolds number ratios (Reliquid/Regas) were used ranging from 4 to 42. In addition, three values of the inlet width ratio (Dgas/Dliquid) were used. Results for the 3-D cases capture the actual shape of the air bubble with the thin film between the bubble and the walls. Also, increasing Reliquid increases the rate of the development of the air bubble. The bubble length increases with the increase of Dgas/Dliquid. For the same values of Re, the rate of growth of the bubble increases with the increase of Dgas/Dliquid. Finally, a correlation is provided to predict the length of the bubble with liquid-gas Reynolds number ratio (Reliquid/Regas) and tube width.

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