Reliability of evaluations for the choice of system solutions at the example of automated order-picking systems for bagged goods

There is a steadily increasing pressure on cost-savings and productivity growth in sectors of order-picking such that the wish for rationalization by automation is rising. Special problems are faced trying to automatize handling operations of order-picking articles packed in bags. The mechanical properties of the objects and their hard-to-predict shape and position represent obstacles and are complicating handling operations. A systematic approach in system design is required. This article deals with the properties of such products under aspects of difficulties arising in automated handling and points out a useful system development methodology.

Metaheuristics for the Order Batching Problem in Manual Order Picking Systems

In manual order picking systems, order pickers walk or drive through a distribution warehouse in order to collect items which are requested by (internal or external) customers. In order to perform these operations efficiently, it is usually required that customer orders are combined into (more substantial) picking orders of limited size. The Order Batching Problem considered in this paper deals with the question of how a given set of customer orders should be combined such that the total length of all tours is minimized which are necessary to collect all items. The authors introduce two metaheuristic approaches for the solution of this problem: the first one is based on Iterated Local Search; the second on Ant Colony Optimization. In a series of extensive numerical experiments, the newly developed approaches are benchmarked against classic solution methods. It is demonstrated that the proposed methods are not only superior to existing methods but provide solutions which may allow distribution warehouses to be operated significantly more efficiently.

Comparison of performance measurement-systems used for order-picking

In consequence of rapidly changing market demands companies are permanently encouraged to review their own processes and structures and to modify them. Being one of these developments, order-picking is involved as part of an intra-logistics system. But to take appropriate actions, system performance and system costs have to be measured permanently. Concerning this the use of performance measurement-systems as further development of traditional systems of key figures is suitable. In this paper various performance measurement-systems are compared and their suitability for an implementation in order-picking systems is estimated. On the basis of the result of the evaluation a first concept of a performance measurement-system for order-picking will be developed by using typical key figures that are mentioned in academic literature. Finally, hints for a necessary detailed implementation and evaluation in practice will be given.

Learning Curves of Temporary Workers in Manual Order Picking Activities

Person-to-stock order picking is highly flexible and requires minimal investment costs in comparison to automated picking solutions. For these reasons, tradi-tional picking is widespread in distribution and production logistics. Due to its typically large proportion of manual activities, picking causes the highest operative personnel costs of all intralogistics process. The required personnel capacity in picking varies short- and mid-term due to capacity requirement fluctuations. These dynamics are often balanced by employing minimal permanent staff and using seasonal help when needed. The resulting high personnel fluctuation necessitates the frequent training of new pickers, which, in combination with in-creasingly complex work contents, highlights the im-portance of learning processes in picking. In industrial settings, learning is often quantified based on diminishing processing time and cost requirements with increasing experience. The best-known industrial learning curve models include those from Wright, de Jong, Baloff and Crossman, which are typically applied to the learning effects of an entire work crew rather than of individuals. These models have been validated in largely static work environments with homogeneous work contents. Little is known of learning effects in picking systems. Here, work contents are heterogeneous and individual work strategies vary among employees. A mix of temporary and steady employees with varying degrees of experience necessitates the observation of individual learning curves. In this paper, the individual picking performance development of temporary employees is analyzed and compared to that of steady employees in the same working environment.

Wearable Computing und RFID in Produktion und Logistik – Ansätze zur bereichsübergreifenden Nutzung digitaler Informationen

Die voranschreitende Entwicklung von Konzepten und Systemen zur Nutzung digitaler Informationen im industriellen Umfeld eröffnet verschiedenste Möglichkeiten zur Optimierung der Informationsverarbeitung und damit der Prozesseffektivität und -effizienz. Werden die relevanten Daten zu Produkten oder Prozessen jedoch lediglich in digitaler Form zur Verfügung gestellt, fällt ein Eingriff des Menschen in die virtuelle Welt immer schwerer. Auf Grundlage dessen wird am Beispiel der RFIDTechnologie dargestellt, inwiefern digitale Informationen durch die Verwendung von in den Arbeitsablauf integrierten Systemen für den Menschen nutzbar werden. Durch die Entwicklung eines Systems zur papierlosen Produktion und Logistik werden exemplarisch Einsatzszenarien zur Unterstützung des Mitarbeiters in Montageprozessen sowie zur Vermeidung von Fehlern in der Kommissionierung aufgezeigt. Dazu findet neben einer am Kopf getragenen Datenbrille zur Visualisierung der Informationen ein mobiles RFID-Lesegerät Anwendung, mit Hilfe dessen die digitalen Transponderdaten ohne zusätzlichen Aufwand für den Anwender genutzt werden können.

Fehlervermeidung in der Kommissionierung

Manuelle Kommissioniersysteme sind aufgrund ihrer Flexibilität weit verbreitet, jedoch treten bei diesen auch vermehrt Kommissionierfehler auf, die weitreichende Folgen haben können. Deshalb werden zu Beginn des Beitrags die Auswirkungen und Ursachen von Kommissionierfehlern betrachtet. Der Fokus des Beitrags liegt auf der Darlegung von Möglichkeiten zur Fehlervermeidung. Dabei wird ein ganzheitlicher Ansatz verfolgt, der Maßnahmen aus den Handlungsfeldern Technik, Prozess, Organisation und Motivation umfasst. Als Ausblick auf zukünftige technische Hilfsmittel zur Fehlervermeidung wird das Augmented-Reality-unterstützte System Pick-by-Vision aus der Forschung vorgestellt, das wesentliche Vorteile existierender Techniken der Informationsbereitstellung vereinigt.

Agentenbasiertes Planungsmodell für die Grobplanung von Kommissioniersystemen

Rechnergestützte Modellansätze, die Logistiksysteme gestalten und generieren, sind eine hochkomplexe Aufgabenstellung. Die bisher in der Praxis existierenden Planungs- und Steuerungsmodelle für Intralogistiksysteme weisen für die aktuellen und zukünftigen Anforderungen wie der Komplexitätsbewältigung, Reaktionsschnelligkeit und Anpassungsfähigkeit Schwachstellen auf. – Ein innovativer Ansatz, diesen Ansprüchen gerecht zu werden, stellen Multiagentensysteme dar. Mit ihrem dezentralen und modularen Charakter sind sie für ein komplexes Problem mit einem geringen Grad an Strukturiertheit geeignet. Außerdem ermöglichen diese computergestützten intelligenten Systeme den Anwendern eine einfache und aufwandsarme Handhabung.

An evaluation of cotton dust control systems in the picking and garnetting areas of the Atlanta Federal Penitentiary /

Mode of access: Internet.

Tropical dryland agroforestry on clay soils: : Analysis of systems based on Acacia senegal in the Blue Nile region, Sudan

Acacia senegal, the gum arabic producing tree, is the most important component in traditional dryland agroforestry systems in the Blue Nile region, Sudan. The aim of the present study was to provide new knowledge on the potential use of A. senegal in dryland agroforestry systems on clay soils, as well as information on tree/crop interaction, and on silvicultural and management tools, with consideration on system productivity, nutrient cycling and sustainability. Moreover, the aim was also to clarify the intra-specific variation in the performance of A. senegal and, specifically, the adaptation of trees of different origin to the clay soils of the Blue Nile region. In agroforestry systems established at the beginning of the study, tree and crop growth, water use, gum and crop yields, nutrient cycling and system performance were investigated for a period of four years (1999 to 2002). Trees were grown at 5 x 5 m and 10 x 10 m spacing alone or in mixture with sorghum or sesame; crops were also grown in sole culture. The symbiotic biological N2 fixation by A. senegal was estimated using the 15N natural abundance (δ15N) procedure in eight provenances collected from different environments and soil types of the gum arabic belt and grown in clay soil in the Blue Nile region. Balanites aegyptiaca (a non-legume) was used as a non-N-fixing reference tree species, so as to allow 15N-based estimates of the proportion of the nitrogen in trees derived from the atmosphere. In the planted acacia trees, measurements were made on shoot growth, water-use efficiency (as assessed by the δ13C method) and (starting from the third year) gum production. Carbon isotope ratios were obtained from the leaves and branch wood samples. The agroforestry system design caused no statistically significant variation in water use, but the variation was highly significant between years, and the highest water use occurred in the years with high rainfall. No statistically significant differences were found in sorghum or sesame yields when intercropping and sole crop systems were compared (yield averages were 1.54 and 1.54 ha-1 for sorghum and 0.36 and 0.42 t ha-1 for sesame in the intercropped and mono-crop plots, respectively). Thus, at an early stage of agroforestry system management, A. senegal had no detrimental effect on crop yield, but the pattern of resource capture by trees and crops may change as the system matures. Intercropping resulted in taller trees and larger basal and crown diameters as compared to the development of sole trees. It also resulted in a higher land equivalent ratio. When gum yields were analysed it was found that a significant positive relationship existed between the second gum picking and the total gum yield. The second gum picking seems to be a decisive factor in gum production and could be used as an indicator for the total gum yield in a particular year. In trees, the concentrations of N and P were higher in leaves and roots, whereas the levels of K were higher in stems, branches and roots. Soil organic matter, N, P and K contents were highest in the upper soil stratum. There was some indication that the P content slightly increased in the topsoil as the agroforestry plantations aged. At a stocking of 400 trees ha-1 (5 x 5 m spacing), A. senegal accumulated in the biomass a total of 18, 1.21, 7.8 and 972 kg ha-1of N, P, K and OC, respectively. Trees contributed ca. 217 and 1500 kg ha-1 of K and OC, respectively, to the top 25-cm of soil over the first four years of intercropping. Acacia provenances of clay plain origin showed considerable variation in seed weight. They also had the lowest average seed weight as compared to the sandy soil (western) provenances. At the experimental site in the clay soil region, the clay provenances were distinctly superior to the sand provenances in all traits studied but especially in basal diameter and crown width, thus reflecting their adaptation to the environment. Values of δ13C, indicating water use efficiency, were higher in the sand soil group as compared to the clay one, both in leaves and in branch wood. This suggests that the sand provenances (with an average value of -28.07 ) displayed conservative water use and high drought tolerance. Of the clay provenances, the local one (Bout) displayed a highly negative (-29.31 ) value, which indicates less conservative water use that resulted in high productivity at this particular clay-soil site. Water use thus appeared to correspond to the environmental conditions prevailing at the original locations for these provenances. Results suggest that A. senegal provenances from the clay part of the gum belt are adapted for a faster growth rate and higher biomass and gum productivity as compared to provenances from sand regions. A strong negative relationship was found between the per-tree gum yield and water use efficiency, as indicated by δ13C. The differences in water use and gum production were greater among provenance groups than within them, suggesting that selection among rather than within provenances would result in distinct genetic gain in gum yield. The relative δ15N values ( ) were higher in B. aegyptiaca than in the N2-fixing acacia provenances. The amount of Ndfa increased significantly with age in all provenances, indicating that A. senegal is a potentially efficient nitrogen fixer and has an important role in t agroforestry development. The total above-ground contribution of fixed N to foliage growth in 4-year-old A. senegal trees was highest in the Rahad sand-soil provenance (46.7 kg N ha-1) and lowest in the Mazmoom clay-soil provenance (28.7 kg N ha-1). This study represents the first use of the δ15N method for estimating the N input by A. senegal in the gum belt of Sudan. Key words: Acacia senegal, agroforestry, clay plain, δ13C, δ15N, gum arabic, nutrient cycling, Ndfa, Sorghum bicolor, Sesamum indicum

MAX: A Multi Objective Memory Architecture eXploration Framework for Embedded Systems-on-Chip

Today's feature-rich multimedia products require embedded system solution with complex System-on-Chip (SoC) to meet market expectations of high performance at a low cost and lower energy consumption. The memory architecture of the embedded system strongly influences these parameters. Hence the embedded system designer performs a complete memory architecture exploration. This problem is a multi-objective optimization problem and can be tackled as a two-level optimization problem. The outer level explores various memory architecture while the inner level explores placement of data sections (data layout problem) to minimize memory stalls. Further, the designer would be interested in multiple optimal design points to address various market segments. However, tight time-to-market constraints enforces short design cycle time. In this paper we address the multi-level multi-objective memory architecture exploration problem through a combination of Multi-objective Genetic Algorithm (Memory Architecture exploration) and an efficient heuristic data placement algorithm. At the outer level the memory architecture exploration is done by picking memory modules directly from a ASIC memory Library. This helps in performing the memory architecture exploration in a integrated framework, where the memory allocation, memory exploration and data layout works in a tightly coupled way to yield optimal design points with respect to area, power and performance. We experimented our approach for 3 embedded applications and our approach explores several thousand memory architecture for each application, yielding a few hundred optimal design points in a few hours of computation time on a standard desktop.

Biased group decision-making and the effect of computer-mediated communication: separating the effects of anonymity, voting and blind picking

The influence of communication technology on group decision-making has been examined in many studies. But the findings are inconsistent. Some studies showed a positive effect on decision quality, other studies have shown that communication technology makes the decision even worse. One possible explanation for these different findings could be the use of different Group Decision Support Systems (GDSS) in these studies, with some GDSS better fitting to the given task than others and with different sets of functions. This paper outlines an approach with an information system solely designed to examine the effect of (1) anonymity, (2) voting and (3) blind picking on decision quality, discussion quality and perceived quality of information.

'The witness who saw, /He left little doubt' : a comparative consideration of expert testimony in mental disability law cases in common and civil law systems

The question of how courts assess expert evidence - especially when mental disability is an issue - raises the corollary question of whether courts adequately evaluate the content of the expert testimony or whether judicial decision making may be influenced by teleology (cherry picking evidence), pretextuality (accepting experts who distort evidence to achieve socially desirable aims), and/or sanism (allowing prejudicial and stereotyped evidence). Such threats occur despite professional standards in forensic psychology and other mental health disciplines that require ethical expert testimony. The result is expert testimony that, in many instances, is at best incompetent and at worst biased. The paper details threats to competent expert testimony in a comparative law context - in both the common law (involuntary civil commitment laws and risk assessment criminal laws) and, more briefly, civil law. We conclude that teleology, pretextuality, and sanism have an impact upon judicial decision making in both the common law and civil law. Finally, we speculate as to whether the new United Nations Convention on the Rights of Persons with Disabilities is likely to have any impact on practices in this area. Copyright © 2009 John Wiley & Sons, Ltd.

Algoritmo genético aplicado ao sequenciamento de picking e faturamento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Bin picking de objetos polimórficos convexos usando perceção 3D

O bin picking é um processo de grande interesse na indústria, uma vez que permite maior automatização, aumento da capacidade de produção e redução dos custos. Este tem vindo a evoluir bastante ao longo dos anos e essa evolução fez com que sistemas de perceção 3D começassem a ser implementados. Este trabalho tem como principal objetivo desenvolver um sistema de bin picking usando apenas perceção 3D. O sistema deve ser capaz de determinar a posição e orientação de objetos com diferentes formas e tamanhos, posicionados aleatoriamente numa superfície de trabalho. Os objetos utilizados para fazer os testes experimentais, são esferas, cilindros e prismas, uma vez que abrangem as formas geométricas existentes em muitos produtos submetidos a bin picking. Após a identi cação e seleção do objeto a apanhar, o manipulador deve autonomamente posicionar-se para fazer a aproximação e recolha do mesmo. A aquisição de dados é feita através de uma câmara Kinect. Dos dados recebidos apenas são trabalhados os referentes à profundidade, centrando-se assim este trabalho na análise e tratamento de nuvem de pontos. O sistema desenvolvido cumpre com os objetivos estabelecidos. Consegue localizar e apanhar objetos em várias posições e orientações. Além disso apresenta uma velocidade de processamento compatível com a aplicação em causa.