Optimization of a Fast-Pick Area in Cosmetics Distribution Center

Poster 1

Optimization of a Fast-Pick Area in a Cosmetics Distribution Center

Fast-pick areas are commonly used in order picking warehouses to improve labor efficiency by concentrating picking activities within a compact area, thus minimizing the distance traveled by the pickers. One problem that must be solved when a fast-pick area is to be implemented is the so-called assignment-allocation problem. This deals with deciding which products should be assigned to the fast-pick area, and how much space should be allocated to these products. This research was motivated by the picking operation of a cosmetics distribution center where several fast-pick areas are in place. A mixed integer linear programming formulation is proposed for solving the variant of the assignment-allocation problem found in this company. Our computational experiments show that the proposed model is efficient for solving small yet realistic instances of the problem

Hypercomputing from quantum computing

Un hipercomputador computa funciones que son incomputables por una maquina de Turing. Recientemente, Tien D. Kieu ha propuesto un algoritmo hipercomputacional cuántico, el cual emplea como referente físico el oscilador armónico cuántico y resuelve en principio el decimo problema de Hilbert. Se realiza un análisis del algoritmo de Kieu y se deduce que esta sustentado en ciertas propiedades del ´algebra Weyl-Heisenberg, la cual es el ´algebra dinámica asociada al oscilador armónico cuántico; y en una cierta aplicación del teorema adiabático de la mecánica cuántica. Con base en el análisis realizado, se presenta una adaptación algebraica del algoritmo de Kieu, es decir, se presenta un algoritmo a la Kieu sobre el ´algebra de Lie su(1, 1). Debido a que el algebra su(1, 1) admite realizaciones en sistemas físicos en las areas de la ´óptica cuántica, la materia condensada y la física matemática, entre otras; la adaptación realizada amplia el espectro de posibilidades de implementación del algoritmo sobre uno de estos sistemas.A hypercomputer computes functions that are uncomputable by a computing machine. Turing. Recently, Tien D. Kieu has proposed a hypercomputational algorithm quantum, which uses the quantum harmonic oscillator as a physical reference and solves in principle Hilbert's tenth problem. An analysis of the Kieu algorithm is performed and it follows that it is supported by certain properties of the Weyl-Heisenberg algebra, which is the dynamical algebra associated with the quantum harmonic oscillator; and in a certain application of the adiabatic theorem of quantum mechanics. Based on the analysis carried out, an algebraic adaptation of Kieu's algorithm is presented, that is, an algorithm a la Kieu on the Lie algebra of him (1, 1). Because the algebra su(1, 1) supports realizations in physical systems in the areas of quantum optics, matter condensed and mathematical physics, among others; the adaptation carried out widens the spectrum of possibilities of implementing the algorithm on one of these systems

Industria del cemento: ¿cuál sería el efecto de los impuestos a sus emisiones de carbono?

Este producto forma parte de una serie de infografías de divulgación científica que buscan reseñar algunas de las investigaciones más importantes en las que ha tenido participación la Universidad EAFIT, publicadas en las revistas especializadas más prestigiosas del mund

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

MAKESPAN MINIMIZATION ON A SINGLE BATCH PROCESSING MACHINE WITH UNEQUAL JOB READY TIMES

A batch processing machine (BPM) can process several jobs simultaneously as a batch as long as its capacity is not violated. The processing time of each job, their ready times and sizes are given. This research was motivated by a practical application observed at an electronics manufacturing facility where a BPM is a bottleneck and consequently minimizing the makespan is the primary objective. The batch processing time is the largest processing time among the jobs in the batch, and the batch ready time is the largest ready time among the jobs in the batch. Given that the problem is NP-hard we propose a constructive heuristic to solve the problem under the assumptions of non-identical job sizes and non-zero job ready times. The computational experiments conducted on a set of randomly generated problem instances show that the proposed approach outperforms other approaches available in the literature at a reasonable computational cost

Scheduling identical parallel batch processing machines to minimise makespan using genetic algorithms

This paper aims to minimise the makespan of a set of identical batch processing machines in parallel. The batch processing machine can process a batch of jobs as long as the total size of all the jobs in the batch does not exceed its capacity. The processing time of the job and its size are given. Batch processing time is equal to the longest processing job in the batch. Two interdependent decisions are required, namely grouping jobs into batches, and scheduling the batches on the machines. The problem under study is NP-hard and hence a Genetic Algorithm (GA) approach is proposed. The effectiveness of the GA approach to solve randomly generated problems was compared with a Simulated Annealing (SA) approach, a Random Keys Genetic Algorithm (RKGA), a Hybrid Genetic Heuristic (HGH) and a commercial solver. The proposed GA approach was found to be very effective in finding a good solution in a short time as opposed to SA, RKGA and a commercial solver. Both GA and HGH are marginally better than each other on different problem instances. [Submitted 17 August 2007; Revised 10 October 2007; Revised 30 May 2008; Revised 29 July 2008; Accepted 15 September 2008]parallel processing; batch processing; parallel machines; scheduling; genetic algorithms; GAs; makespan.

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice

Safety and efficacy of intraperitoneal drain placement after emergency colorectal surgery. An international, prospective cohort study

Intraperitoneal drains are often placed during emergency colorectal surgery. However, there is a lack of evidence supporting their use. This study aimed to describe the efficacy and safety of intraperitoneal drain placement after emergency colorectal surgery. Method: COMPlicAted intra-abdominal collectionS after colorectal Surgery (COMPASS) is a prospective, international, cohort study into which consecutive adult patients undergoing emergency colorectal surgery were enrolled (from 3 February 2020 to 8 March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included rate and time-to-diagnosis of postoperative intraperitoneal collections, rate of surgical site infections (SSIs), time to discharge and 30-day major postoperative complications (Clavien-Dindo III-V). Multivariable logistic and Cox proportional hazards regressions were used to estimate the independent association of the outcomes with drain placement. Results: Some 725 patients (median age 68.0 years; 349 [48.1%] women) from 22 countries were included. The drain insertion rate was 53.7% (389 patients). Following multivariable adjustment, drains were not significantly associated with reduced rates (odds ratio [OR] = 1.56, 95% CI: 0.48-5.02, p = 0.457) or earlier detection (hazard ratio [HR] = 1.07, 95% CI: 0.61-1.90, p = 0.805) of collections. Drains were not significantly associated with worse major postoperative complications (OR = 1.26, 95% CI: 0.67-2.36, p = 0.478), delayed hospital discharge (HR = 1.11, 95% CI: 0.91-1.36, p = 0.303) or increased risk of SSIs (OR = 1.61, 95% CI: 0.87-2.99, p = 0.128). Conclusion: This is the first study investigating placement of intraperitoneal drains following emergency colorectal surgery. The safety and clinical benefit of drains remain uncertain. Equipoise exists for randomized trials to define the safety and efficacy of drains in emergency colorectal surgery