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EN
The article presents the idea of creating trading systems using Dempster-Shafer theory. Simple (usually one-day) technical analysis formations were used to generate signals. The system is created in two stages. Initially, based on historical data, for a defined set of focal elements, the basic probability assignment of each formation is calculated. The probability distributions can then be united using the Dempster rule. The empirical part examines whether it would be possible to create the transactional system described for a futures contract on the WIG20 index. The result was negative. The likely causes rendering the construction of such a system very difficult are described.
PL
W artykule opisano zasady działania magazynów automatycznych typu miniload i porównano kilka koncepcji składowania towarów. Analizie poddany został wariant magazynu, w którym w jednej lokalizacji składowane mogą być dwie kuwety z towarami. Opisane w literaturze składowanie oparte na podziale na grupy towarów w oparciu o współczynnik rotacji (zgodnie z klasyfikacją ABC) może dla analizowanego wariantu powodować pewne trudności i w efekcie nie zawsze prowadzić do redukcji średniego czasu pobrania towaru. W pracy podano pewne modyfikacje tego rozwiązania. Wyniki opracowano z wykorzystaniem autorskiego narzędzia symulacyjnego.
EN
In the paper the operating principles of the Miniload Automated Storage/Retrieval Systems were described and a few storage location assignment methods were developed and compared. The analysis included the variant in which in one slot two bins can be stored and the miniload crane transports one or two bins at the same time. Using the simple ABC classification in that case may cause some problems and not lead directly to the reduction of order-picking time. In the paper the other solutions were developed. The results were processed by the simulation tool made by the author of this paper.
PL
Istotnym elementem funkcjonowania magazynów, podlegającym optymalizacji, jest czas kompletacji wyrobów. Może być on minimalizowany poprzez wyznaczenie jak najkrótszej trasy magazyniera, ale również dzięki właściwemu rozmieszczeniu towarów. W artykule rozważania ograniczono do najpopularniejszych magazynów: prostokątnych, jednoblokowych z kompletacją typu „człowiek do towaru”. Omówione zostały procesy magazynowe i ich wpływ na czas kompletacji wyrobów. Przedstawiona została podstawowa klasyfikacja metod składowania towarów i sposoby wyznaczania trasy magazynierów. Na tym tle zaprezentowano oryginalne metody składowania dedykowanego. Jakość proponowanych metod zweryfikowana została za pomocą symulacji. Otrzymane czasy kompletacji towarów porównano z czasami uzyskanymi dla jednej z metod losowych. Do obliczeń wykorzystano autorski program Warehouse Real-Time Simulator.
EN
An essential element of warehouse work which can be optimised is order-picking time. It can be minimised by determining the shortest picker’s route and the appropriate storage location assignment of items. In this paper only one-block rectangular warehouses with picker-to-part order picking systems are considered. The warehouse processes are presented. The routing heuristics and the optimal algorithm and storage location assignment methods are described. Against this background the original dedicated storage location assignment algorithms are presented. The efficiency of the methods is verified using simulations. For the calculations the original software Warehouse Real-Time Simulator is used.
EN
This paper presents the order-picking problem as a multicriteria task. Using simulation tool 360 variants of solution were generated. The different combinations of the picking zone's shape, the number of forklift trucks and the picker-routing methods were considered. The variants were evaluated by seven criteria and the dominated solutions were removed. Then, using the Electre I method, the number of solutions was even more limited. The paper discusses and presents conclusions how to optimize the order-picking process.
EN
Pick-and-pass systems are a part of picker-to-parts order-picking systems and constitute a very common storage solution in cases where customer orders are usually small and need to be completed very quickly. As workers pick items in the zones connected by conveyors, their work needs to be coordinated. The paper presents MILP models that optimize the order-picking process. The first model uses information about the expected demand for items to solve the storage location problem and balance the workload across zones. The task of the next model is order-batching and sequencing – two concepts are presented that meet different assumptions. The results of the exemplary tasks solved with the use of the proposed MILP models show that the total picking time of a set of orders can be reduced by about 35-45% in comparison with random policies. The paper presents an equation for the lower bound of a makespan. Recommendations about the number of zones that guarantee the required system efficiency are also introduced.
PL
W artykule wyprowadzono wzory matematyczne na średnie odległości pokonywane podczas cyklu kompletacji zamówień dla heurystyki s-shape. Rozważono magazyny prostokątne jednoblokowe ze scentralizowanym punktem przyjęcia i wydania towarów umieszczonym naprzeciwko pierwszej bocznej alejki. Skuteczność metod zweryfikowano za pomocą symulacji. Uzyskane wyniki są lepsze niż te, które można otrzymać stosując dobrze znane wzory Halla. Podano przyczyny stosunkowo dużych wartości błędów oszacowania średnich czasów kompletacji metodą Halla.
EN
The paper presents equations for average order-picking times (in fact average distances) for s-shape heuristic. One-block rectangular warehouse with centralized PD was considered. The effectiveness of equations was verified by simulations. The results are better than well known Hall's approach. The reasons why Hall's equations generate relatively large error values were described.
EN
The paper presents a case study of one of the picking zones of real Polish logistics centre of automotive parts and accessories. The aim of the study was to compare the effectiveness of different order-picking methods. The work organization in the warehouse was briefly presented. Then different routing methods in the one block rectangular warehouse were described (heuristics and optimal algorithm). The paper compares different variants of order-picking process and presents their ranking. The graphs of cumulative distribution functions of order-picking time may help the survey. The analysis was based on real data. Calculations were performed using a simulation with the use of Warehouse Real-Time Simulator.
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