Robotized Warehouse Systems: Developments and Research Opportunities

Robotized handling systems are increasingly applied in distribution centers. They require little space, provide flexibility in managing varying demand requirements, and are able to work 24/7. This makes them particularly fit for e-commerce operations. This paper reviews new categories of robotized handling systems, such as the shuttle-based storage and retrieval systems, shuttle-based compact storage systems, and robotic mobile fulfillment systems. For each system, we categorize the literature in three groups: system analysis, design optimization, and operations planning and control. Our focus is to identify the research issue and OR modeling methodology adopted to analyze the problem. We find that many new robotic systems and applications have hardly been studied in academic literature, despite their increasing use in practice. Due to unique system features (such as autonomous control, networked and dynamic operation), new models and methods are needed to address the design and operational control challenges for such systems, in particular, for the integration of subsystems. Integrated robotized warehouse systems will form the next category of warehouses. All vital warehouse design, planning and control logic such as methods to design layout, storage and order picking system selection, storage slotting, order batching, picker routing, and picker to order assignment will have to be revisited for new robotized warehouses

Vertical or Horizontal Transport? - Comparison of robotic storage and retrieval systems

Autonomous vehicle-based storage and retrieval systems are commonly used in e-commerce fulfillment as they allow a high and flexible throughput capacity. In these systems, roaming robots transport loads between a storage location and a workstation. Two main variants exist: Horizontal, where the robots only move horizontally and use lifts for vertical transport and a new variant Vertical, where the robots can also travel vertically in the rack. This paper builds a framework to analyze the performance of the vertical system and to compare its throughput capacity with the horizontal system. We build closed-queueing network models for this that in turn are used to optimize the design. The results show that the optimal height-to-width ratio of a vertical system is around 1. As a large number of system robots may lead to blocking and delays, we compare the effect of two different robot blocking protocols on the system throughput: robot Recirculation and Wait-On-Spot. The Wait-On-Spot policy produces a higher system throughput when the number of robots in the system is small. However, for a large number of robots in the system, the Recirculation policy dominates the Wait-On-Spot policy. Finally, we compare the operational costs of the vertical and the horizontal transport system. For systems with one load/unload (L/U) point, the vertical system always produces a similar or higher system throughput, with a lower operating cost comp

Optical Studies of Er-doped Yttrium Aluminium Garnet Phosphor Materials

The need for materials application in solid-state lasers, medical devices, and optoelectronic devices has made the investigation of ceramic materials of increasing importance. A detail study of the optical properties of rare earth element typically from luminescent materials when intentionally doped inside the host materials and in particular crystal (such as YAG) is reported for the photoluminescence, power and lifetime measurement. The rare-earth dopants usually form trivalent lanthanide ions and the energy transfer and optical transitions involved originate from 4f-4f transitions of the ions and between these states and the host material. In order to understand the energy transfer processes in more detail we need to better understand the accompanying optical processes that give rise to the emission they display and it is this that forms the focus of the work presented. Following this second (and higher) order processes are considered that lead to upconversion in erbium-doped yttrium aluminum garnet (Er:YAG) materials

Statistics of fluctuations for two types of crossover: from ballistic to diffusive regime and from orthogonal to unitary ensemble

In our previous publication [Kogan et al, Phys. Rev. {\bf 48}, 9404 (1993)] we considered the issue of statistics of radiation diffusively propagating in a disordered medium. The consideration was in the framework of diagrammatic techniques and a new representation for the intensity distribution function in terms of connected diagrams only was proposed. Here we use similar approach to treat the issue of statistics in the regime of the crossover between ballistic and diffusive transport. We find that even small contribution from coherent component decreases by one half the intensity distribution function for small values of intensity and also produces oscillations of the distribution function. We also apply this method to study statistics of fluctuations of wave functions of chaotic electrons in a quantum dot in an arbitrary magnetic field, by calculating the single state local density in the regime of the crossover between the orthogonal and unitary ensemble.Comment: Revtex, 3 pages + 2 ps.figures in uuencoded file, a version which clarifies and unites the results of two previous submission

Endometriosis of diaphragm: A case report

Endometriosis affects about 10 of women of reproductive age. Its main feature is the presence of stroma and endometrial glands in sites other than the uterus, mainly in pelvis. Pelvic peritoneum, ovaries, uterine ligaments, bladder, intestines, andcul-de-sac are among the affected areas. Sometimes endometriosis can be found outside of the pelvis and even above abdominal cavity, like indiaphragm.Herein, we present a case of an asymptomatic diaphragmatic endometriosis that was discovered incidentally during laparoscopy of pelvic endometriosis, as well as our appropriately proposed treatment protocol. © 2018, Royan Institute (ACECR). All rights reserved

Effects of an Osteoporosis Prevention Program Based on Health Belief Model Among Females

Background: Several studies reported the efficacy of osteoporosis prevention interventions in improvement of people’s preventive behaviors. However, there are reports that the interventions were not successful in altering osteoporosis health beliefs and preventive behaviors. Objectives: The current study aimed to assess the effect of a program based on health beliefs model (HBM) on females’ health beliefs and performances about osteoporosis preventive behaviors. Patients and Methods: This quasi-experimental study was conducted on 120 patients registered in two healthcare centers of Fasa, Fars Province, Iran in 2014. A questionnaire including demographic information and HBM constructs was employed to measure the females’ beliefs regarding nutrition and walking performance in prevention of osteoporosis bone mineral density (BMD) measured at the lumbar spine and femur before, immediately after the intervention, and six months after the intervention. Data were analyzed using Chi-square, independent samples t-, Mann-Whitney U tests and repeated measures ANOVA. Results: Immediately and six months after the intervention, a significant increase was found in the intervention group’s health beliefs, nutrition, and walking performances to prevent osteoporosis. Six months after the intervention, lumbar spine BMD T-score increased to 0.127 ± 0.061 in the intervention group but reduced to -0.043 ± 0.059 in the control group. Also, hip BMD T-score increased to 0.125 ± 0.088 in the intervention group, but decreased to -0.028 ± 0.052 in control group. Conclusions: The current study showed the effectiveness of HBM in adoption of nutrition and walking behaviors as well as the increase of bone density to prevent osteoporosis