Rack Layout Research Articles

LEAN SIX SIGMA APPROACH TO IMPROVE THE PRODUCTION PROCESS IN THE GARMENT COMPANY: A CASE STUDY

PT “X” is a company engaged in the garment industry. The company is facing problems that inhibit the production process. These problems comprise an excess of product defects beyond the specified limits, a considerable rate of product returns, delays in product shipment, and disorderly arrangements in storing raw material. This study aims to determine the root causes of problems in the PT “X” and provide recommendations for improvement using the concept of lean six sigma. The waste assessment model is used to identify the dominant waste, while the value stream analysis tools is a method used to analyze the causes of the dominant waste. From the research results, four dominant wastes are identified, namely waste defects, unnecessary inventory, waiting and unnecessary motion, with percentages of 27.02%, 15.92%, 14.32% and 14.0% respectively. The results of the analysis using mapping tools show the details of waste in each dominant waste. Proposed recommendations for improvement are made using the failure mode and effect analysis based on the highest risk priority number for each dominant waste. The recommendations proposed by the researchers include implementing a standard operating procedure and work instruction for the sewing process; scheduling machine maintenance using reliability centered maintenance II; planning and scheduling materials using material requirement planning; implementing line balancing; and designing name tags, visual displays, and storage rack layout.

Layout optimisation of fishbone robotic mobile fulfilment system

Robotic mobile fulfilment system (RMFS) heavily influences all traditional scheduling problems when operating a warehouse. Rack layout affects the efficiency of inbound and outbound and the utilisation ratio of storage. This paper focuses on analysing the compatibility between fishbone storage layout and RMFS and its equipment kinetic characteristics, such as movement velocity and acceleration. By building the equipment kinetic functions and subsequently simulating various fishbone storage layout solutions features by length-to-width ratio, storage volume, and rack size, this research analyses the relationship between inbound/outbound efficiency and warehouse space utilisation. The applicability range of fishbone rack layout is obtained by comparing conventional layout with different rack size. Meanwhile, energy consumption is of great significance to reduce warehousing operating costs and improve operational efficiency. Therefore, the impacts on inbound/outbound efficiency and energy consumption from velocity and acceleration are investigated. Results show that optimal velocity ranges between 1.5 m/s and 2 m/s and the optimal acceleration ranges between 0.2 m/s2 and 0.25 m/s2. Too high acceleration or velocity is easy to cause congestion and deadlock, which is not easy to schedule. Overall, this research provides decision support for parts-to-picker system design. [Submitted: 19 March 2021; Accepted: 22 September 2021]

Joint determination of rack configuration and shelf space allocation for a retailer

For brick-and-mortar retailers to be successful, it is critical for them to optimize their rack layout and product placement to draw the attention of shoppers. Recent studies show that racks placed at a non-90° angle along the shopper's path or rack heights positioned below a shopper's eye-height can provide improved visibility of products on those racks. While this can increase the likelihood of a shopper entering that aisle for an impulse purchase, the increase in floor space and restocking costs cannot be ignored. To address these tradeoffs, we propose the Joint Rack Configuration and Shelf Space Allocation (JRC-SSA) problem that jointly determines rack decisions (orientation and height) and product decisions (placement and number of locations) in order to maximize the retailer's impulse profit. We propose an optimization model for JRC-SSA and solve it using a Particle Swarm Optimization based algorithm. Results indicate that a retailer can realize up to 10.1% increase in profit through the JRC-SSA compared to a traditional 7 ft high rack placed at 90° orientation. Acute-angled racks appear to increase impulse profit over 90° racks at low space costs; shorter racks appear prominent for low restocking costs. We also notice that product location and allocation on the rack were altered substantially; high impulse products were often switched from the front to the back face (or vice-versa) to maintain high visibility in different rack orientations. Retailers can use these findings to redesign store sections for enhanced product visibility, which would not only increase their revenue, but also improve shopper experience.

Evaluating exposure of a retail rack layout in 3D

Analyzing a retail layout accounting for how a shopper visually interacts with racks along their shopping path can help the retailer identify hot-warm-cold spots and better allocate products to racks in order to maximize revenue. We focus on estimating exposure (which locations are likely to be seen) and the intensity of exposure (how long are they seen) by accounting for the dynamic interaction between the human 3D field of regard with a physical rack layout. Our quantitative approach allows us to analyze the effect of varying layout design parameters (i.e., rack orientation, curvature, and height) on exposure considering both unidirectional and bidirectional travel. We also validate our approach through human participants in a virtual layout. We observed that curving racks in a layout with racks oriented 90° (i.e., perpendicular to the aisle) increase exposure by 3–121% over straight racks. Further, orientating curved racks at acute angles leads to substantially higher exposure (18–321%) over straight racks at 90°. Moreover, racks with a height just below shopper eye-height results in higher exposure over racks just above eye-height when top surfaces are accounted for as exposed. Considering the trade-off between exposure and layout floor space, when given an allowable 25% increase in floor space, we found feasible layouts that increased exposure ranging from 15–530% (over straight racks at 90°) depending on shopper scanning pattern, layout size, and traffic direction.

A model to optimize rack layout in a retail store

The physical layout of a retail store is known to influence the attitude and behavior of shoppers and affect store performance. An important role of the store's layout is to expose shoppers to merchandise in order to facilitate consideration and ultimately purchasing of exposed products. This work focuses on determining which rack layouts maximize exposure of products to a shopper. To do this, we introduce the retail rack layout problem (RRLP), which identifies the optimal single or multi-column rack orientations in a constrained space in order to maximize exposure to the shopper. To solve this problem, we propose a mixed-integer, non-linear optimization model, which we solve using a particle swarm optimization (PSO) algorithm. Results indicate that an increase of exposure ranging from 213–226% (small head turns) and 17–18% (large head turns) over 90°-rack layouts can be achieved with angled-racks (acute or obtuse from a shopper's travel path) depending on the duration of exposure. The increase in exposure comes at the expense of loss of display space and is sensitive to the shopper's field of regard (angular limit and depth of vision). We also show that multiple competitive layout designs with 1-, 2-, and even 3-columns may exist for a given system configuration that offer similar exposure values.

The impact of rack layout on visual experience in a retail store

ABSTRACTA retail store's layout affects a shopper's visual experience and correspondingly the time spent in the store, navigation through the aisles, and allocation of attention and money across departments and categories. We show that alternate rack layouts allow for more of a rack's facing to appear in the shopper's visual field. To this end, we introduce a set of visual–spatial statistics comprised of visual measures (exposure and intensity) and spatial measures (space and aspect ratio) as a way to quantify the effect a retail layout has on a shopper's visual experience. We present both analytical and algorithmic approaches to capture the dynamics of a travelling shopper's field of regard with respect to a static rack layout. Results for the case of unidirectional shopper travel suggest that racks oriented at 30° from the direction of travel exhibit nearly 250% increase in exposure when compared to 90° racks; for bidirectional traffic, acute orientations still provide up to 150% higher exposure. Interestingly, rack orientations amenable to higher visual measures are not necessarily the best with respect to spatial measures. We illustrate the use of our approach to analyse a real-store layout from a nearby mass merchandiser.

Data Center Energy and Cost Saving Evaluation

In data centers, about 40% of the total energy is consumed for cooling the IT equipment. Cooling costs are thus one of the major contributors to the total electricity bill of large data centers. This paper studies two factors affecting data center cooling energy consumption, namely air flow management and data center location selection. A unique rack layout with a vertically cooling air flow is proposed. Two cooling systems, computer room air conditioning (CRAC) cooling system and airside economizer (ASE), have been studied. Based on these two cooling systems, four cities have been selected from the worldwide data center locations. A number of energy efficiency metrics are explored for data center cooling, such as power usage effectiveness (PUE), coefficient of performance (COP) and chiller hours. By analyzing the effects of chiller hours and economizer hours, comparative economic results of cooling power consumption are provided in both systems. The results show that the cooling efficiency and operating costs vary significantly with different climate conditions, energy prices and cooling technologies. As climate condition is the major factor which affects the airside economizer, employing the airside economizer in the cold climate yields much lower energy consumption and operation costs.

Integration and conventional systems at STAR

At the beginning of the design and construction of the STAR detector, the collaboration assigned a team of physicists and engineers the responsibility of coordinating the construction of the detector. This group managed the general space assignments for each sub-system and coordinated the assembly and planning for the detector. Furthermore, as this group was the only STAR group with the responsibility of looking at the system as a whole, the collaboration assigned it several tasks that spanned the different sub-detectors. These items included grounding, rack layout, cable distribution, electrical, power and water, and safety systems. This paper describes these systems and their performance.