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작업자 추종 피킹 카트를 도입한 주문피킹 시스템의 시뮬레이션 기반 생산성 분석
이정만(Lee, JeongMan),김영주(Kim, YoungJoo),이태훈(Lee, TaeHoon),홍순도(Hong, SoonDo) 한국물류학회 2020 물류학회지 Vol.30 No.1
물류업체들의 서비스 능력 향상을 위해서는 기존 물류센터의 효율적인 운영이 뒷받침되어야 한다. 이를 위한 자동화 설비의 도입은 효율적인 물류센터 운영을 위한 대안으로 고려되고 있다. 본 연구에서는 자동화 설비 중 하나인 작업자 추종 피킹 카트를 도입한 주문피킹 시스템을 대상으로 기존 운영정책들이 생산성에 미치는 영향을 분석하고자 한다. 먼저 작업자 추종 카트가 존재하는 시스템에 대하여 4가지 운영 정책(개별피킹, 개별 구역피킹, 묶음피킹, 묶음 구역피킹)을 정의하였으며 이산 사건 시뮬레이션 모델을 개발하였다. 또한 운영정책 간 차이, 주문피킹 시스템 내 주문묶음 크기, 그리고 복수 개의 작업자 추종 피킹 카트의 대수 변화를 중점으로 시뮬레이션 비교 실험을 수행하였다. 실험 결과, 기존 운영정책을 통해서도 작업자 추종 피킹 카트를 도입한 물류시스템의 생산성을 개선시킬 수 있었고, zone의 구성과 주문묶음 구성이 자동화 설비를 도입한 물류시스템에 미치는 영향을 확인하였다. 또한, 같은 운영정책이어도 주문묶음의 크기와 주문량 변화에 따라 병목 현상이 발생할 수 있으므로 유연한 대처가 필요하다는 점도 함께 확인하였다. 추가적으로 본 연구 결과를 바탕으로 자동화 설비 도입 전에 시뮬레이션 비교 연구를 통해서 해당 물류센터에 적합한 자동화 설비 설계에 도움이 되는 정보를 얻을 수 있다는 점도 확인할 수 있었다. 본 연구의 향후 연구로는 해당 물류시스템에서의 최적의 zone 크기와 본 연구에서는 다루지 못한 제품의 보관 정책과 작업자 이동경로 정책이 생산성에 미치는 영향에 대한 연구를 제안한다. To improve the service level of logistics companies, efficient operations of current logistics centers should be executed. The introduction of automated facilities is considered an alternative for efficient logistics center operations in order to achieve the above goal. The purpose of this study is to analyze the effects of existing operational policies on productivity in an order picking system with person-following picking carts, one of the automation facilities. In this paper, we define four operation policies for the system with person-following picking carts: discrete picking, discrete zone picking, batch picking, and batch zone picking, and develop discrete-event simulation models to compare the performance among operation policies. Also, we run simulation experiments focusing on differences in operational policies, order batch size, and the number of person-following picking carts. As a result of simulation experiments, we confirmed that the operational policies could improve the productivity of an order picking system with the person-following picking carts. And, we checked that the configuration of the zone and order batch size affect the performance of the system with automated facilities. Besides, we confirmed that bottlenecks could occur according to the scales of orders although the logistics system took the same operational policy. Another finding is that analysis via simulation would be useful for designing the automated facilities before introducing those facilities based on the results of this study. We propose a study on the optimal zone size in the order picking system with person-following picking carts and the effect of the storage policies and routing methods for future research.
이정만(Jeongman Lee),김지현(Ji Hyun Kim),헤녹 열니아스 피브리안토,김갑환(Kap Hwan Kim),홍순도(Soondo Hong) 한국SCM학회 2018 한국SCM학회지 Vol.18 No.2
Configurable flat-glass racks store flat-glasses efficiently and safely while delivering them from a manufacturing facility to construction sites. This paper describes an executable Rack Packing Model (RPM) that determines the number of racks, assigns glasses to racks, and configures each rack for glasses. We formulate an optimal rack packing model using a mixed-integer programming (MIP). We build the MIP model for practical-size problems by dividing the rack-selection procedure and linearizing the rack-configuration-related logical constraints. In addition, we also present a greedy procedure, which is termed as the worker’s First Fit Decreasing heuristic algorithm (FFD). Our computational comparison confirms that both the MIP model and FFD algorithm obtain optimal solutions to practical examples. This comparison result demonstrates that configurable flat-glass racks can be operated efficiently by simple heuristics.
엄인용,박찬준,이정만 서울産業大學校 2005 논문집 Vol.54 No.1
A system to measure the fuel concentration distribution in a steady flow rig on the basis of Rayleigh scattering is presented. The system can be employed to measure both the temporal and the spatial distribution. It is possible to calibrate the system for the measurement of accurate absolute concentration. The system was tested at a calibration chamber for the determination of scattering cross section from propane, butane, acetylene, Freon-12 and Genetron 143a. It was adapted to a steady flow rig to measure the temporal and spatial fuel concentration induced from a cylinder head, intake manifold and injector. To cope with the problem of Mie scattering interference, a software filter was developed with is based on the rise time and the time constant of the photomultiplier-amplifier system. With this developed system measurement were made which showed that LRS can provide useful informations about concentration related parameter. At the same time it was found that ensemble averaging can lead to large error if the flow is unstable.
박찬준,엄인용,이정만 서울産業大學校 2005 논문집 Vol.54 No.1
This paper is to compare the various Air-Fuel ratio determination methods for alternative fuels. In the previous work, expansion of Eltinge chart, unburned hydrocarbon compensation, comparison of the results from various methods were discussed. It has been also concluded that Eltinge method might be regarded as the most general equation, of AFR determination among the existing ones. In the recent years, however, increasing demand for the environmental preservation, including global warming-up protection, and energy conservation lead to introduce the alternative fuel to the internal combustion engine. Therefore, the exact calculations of AFR for these fuels are needed. Especially, for the fuel that contains oxygen, all AFR calculation equations except Eltinge have to be re-formulated. In this paper, the AFR for alternative fuel were calculated by re-formulated carbon balance, accuracy of which was already confirmed, and linear equations, which are newly proposed by statistical method for each fuel. The results show that AFRs based on carbon balance have a little more error compared with gasoline, however, the accuracy is enough for this formula to apply to various fuel. The proposed linear equation also have excellent accuracy up to X = 1.2.