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Jackson, Ilya, Jurijs Tolujevs, and Zhandos Kegenbekov. "Review of Inventory Control Models: A Classification Based on Methods of Obtaining Optimal Control Parameters." Transport and Telecommunication Journal 21, no. 3 (2020): 191–202. http://dx.doi.org/10.2478/ttj-2020-0015.
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AbstractInventory control has been a major point of discussion in industrial engineering and operations research for over 100 years. Various advanced numerical methods can be used for solving inventory control problems, which makes it a highly multidisciplinary filed attracting researchers from different academic disciplines. This fact makes it a daunting task to subsume the gargantuan spectrum of literature related to inventory control theory in one treatise. In light of this fact, this paper focuses on the timeline of inventory control models with respect to methodologies behind deriving optimal control parameters. Such methodologies include analytical approaches, optimal control theory, dynamic programming, simulation-based optimization and metamodel-based optimization.
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Li, Zhan, and Da Shen Xue. "The Application of Simulation Technology in the Inventory System." Applied Mechanics and Materials 380-384 (August 2013): 1473–76. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.1473.
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For a long time, the mathematical model is used to describe the systems characteristics and acquire the solutions, so it gradually develops into a modern computer simulation technology, and it can be used to solve many problems which are complex and unable resolve use mathematical methods. Witness modeling simulation software is applied in this article, and examples analysis is put forward in view of the logistics system of inventory control, finally making the models on the part of the module, whats more, it analysis the data and makes the optimal strategy.
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Diaz, Rafael, and Barry Charles Ezell. "A Simulation-Based Optimization Approach to a Lost Sale Stochastic Inventory Model." International Journal of Operations Research and Information Systems 3, no. 2 (2012): 46–63. http://dx.doi.org/10.4018/joris.2012040103.
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This paper describes a stochastic inventory model where the control review system is periodic; demand contains auto-correlated components; and categorized as a lost sale case. The authors propose a simulation-based optimization based on using a combination of simulated annealing, pattern search, and ranking and selection methods to search and approximate solutions to this problem. Simulated annealing is employed to stochastically nominate and pre-select solutions in a decision space. Pattern search is used to systematically define a grid of competitive neighbors around pre-selected solutions. Ranking and selection is used to evaluate the performance of such competing pre-selected alternatives. On one hand, results show that service level in terms of filling rates deteriorate as the autocorrelation grows and is ignored. In contrast, service levels were kept almost invariable to the effects of the serially correlated components for solutions suggested using the proposed algorithm.
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White, Anthony S., and Michael Censlive. "The Effects of Modelling Strategies on Responses of Inventory Models." International Journal of Applied Industrial Engineering 4, no. 1 (2017): 19–43. http://dx.doi.org/10.4018/ijaie.2017010102.
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This paper describes methods to model inventories from the APVIOBPCS family. It aims to examine the limits of modelling approaches within control-theoretic models using the Simulink package. Discrete and continuous time models were considered together with a finite pipeline delay and the Forrester exponential delay, in continuous and sampled data representation. The main effect of using a finite delay is to deepen the stock-out and increase the required order rate compared with the same response observed with an exponential form delay. Total time for recovery is similar with all models. The discrete performances are close to the continuous representation for a smaller review period. Results presented here illustrate that the various forms of control-theoretic models present similar step response results irrespective of simulation technique used provided they have the same delay type. However, the gains required for minimum cost are substantially different for each delay form and modelling technique used.
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Xiao, Han, Qizhong Wu, Xiaochun Yang, Lanning Wang, and Huaqiong Cheng. "Numerical study of the effects of initial conditions and emissions on PM<sub>2.5</sub> concentration simulations with CAMx v6.1: a Xi'an case study." Geoscientific Model Development 14, no. 1 (2021): 223–38. http://dx.doi.org/10.5194/gmd-14-223-2021.
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Abstract. A series of model sensitivity experiments was designed to explore the effects of different initial conditions and emissions in Xi'an in December 2016; Xi'an is a major city in the Fenwei Plain, which is a key area with respect to air pollution control in China. Three methods were applied for the initial condition tests: a clean initial simulation, a restart simulation, and a continuous simulation. In the clean initial simulation test, the C00, C06, C12, C18, and C24 sensitivity experiments were conducted to explore the effect of the intercepted time periods used. The results of these experiments showed that the fine particulate matter (PM2.5) model performance was better when the start time of the intercepted time periods was delayed. For experiments C00 to C24, the absolute mean bias (MB) decreased from 51.07 to 3.72 µg m−3, and the index of agreement (IOA) increased from 0.49 to 0.86, which illustrates that the model performance of C24 is much better than that of C00. The R1120 and R1124 sensitivity experiments were used to explore the restart simulation and, in turn, the effect of the date of the first day of the model simulation. While the start times of the simulations were different, the simulation results with different start times were nearly consistent after a spin-up time period, and the results revealed that the spin-up time was approximately 27 h. For the continuous simulation test, the CT12 and CT24 sensitivity experiments were conducted. The start times of the intercepted time periods for CT12 and R1120 were the same, and the simulation results were almost identical. Based on the simulation results, CT24 showed the best performance of all of the sensitivity experiments, with the correlation coefficient (R), MB, and IOA reaching 0.81, 6.29 µg m−3, and 0.90 respectively. For the emission tests, an updated local emission inventory with construction fugitive dust emissions was added and was compared with the simulation results from the original emission inventory. The simulation with the updated local emissions showed much better performance for PM2.5 modelling. Therefore, combining the CT24 method and the updated local emission inventory can satisfactorily improve the PM2.5 model performance in Xi'an: the absolute MB decreased from 35.16 to 6.29 µg m−3, and the IOA reached 0.90.
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Liu, Gia-Shie, and Kuo-Ping Lin. "A decision support system of green inventory-routing problem." Industrial Management & Data Systems 119, no. 1 (2019): 89–110. http://dx.doi.org/10.1108/imds-11-2017-0533.
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Purpose The purpose of this paper is to develop a decision support system to consider geographic information, logistics information and greenhouse gas (GHG) emission information to solve the proposed green inventory routing problem (GIRP) for a specific Taiwan publishing logistics firm. Design/methodology/approach A GIRP mathematical model is first constructed to help this specific publishing logistics firm to approximate to the optimal distribution system design. Next, two modified Heuristic-Tabu combination methods that combine savings approach, 2-opt and 1-1 λ-interchange heuristic approach with two modified Tabu search methods are developed to determine the optimum solution. Findings Several examples are given to illustrate the optimum total inventory routing cost, the optimum delivery routes, the economic order quantities, the optimum service levels, the reorder points, the optimum common review interval and the optimum maximum inventory levels of all convenience stores in these designed routes. Sensitivity analyses are conducted based on the parameters including truck loading capacity, inventory carrying cost percentages, unit shortage costs, unit ordering costs and unit transport costs to support optimal distribution system design regarding the total inventory routing cost and GHG emission level. Originality/value The most important finding is that GIRP model with reordering point inventory control policy should be applied for the first replenishment and delivery run and GIRP model with periodic review inventory control policy should be conducted for the remaining replenishment and delivery runs based on overall simulation results. The other very important finding concerning the global warming issue can help decision makers of GIRP distribution system to select the appropriate type of truck to deliver products to all retail stores located in the planned optimal delivery routes depending on GHG emission consumptions.
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Porras, Eric, and Rommert Dekker. "An inventory control system for spare parts at a refinery: An empirical comparison of different re-order point methods." European Journal of Operational Research 184, no. 1 (2008): 101–32. http://dx.doi.org/10.1016/j.ejor.2006.11.008.
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Ma, J., and J. A. van Aardenne. "Impact of different emission inventories on simulated tropospheric ozone over China: a regional chemical transport model evaluation." Atmospheric Chemistry and Physics 4, no. 4 (2004): 877–87. http://dx.doi.org/10.5194/acp-4-877-2004.
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Abstract. The importance of emission inventory uncertainty on the simulation of summertime tropospheric ozone over China has been analyzed using a regional chemical transport model. Three independent emissions inventories, that are (i) emission estimates from the Emission Database for Global Atmospheric Research (EDGAR) for the year 1995, (ii) a regional emission inventory used in the Transport and Chemical Evolution over the Pacific (TRACE-P) program with emissions for the year 2000 and (iii) a national emission inventory used in the China Ozone Research Program (CORP) with emission estimates for the year 1995, are used for model simulation over a summer period. Methods used for the development of the inventories are discussed and differences in simulated ozone and its precursors with these emission inventories are analyzed. Comparison of the emission inventories revealed large differences in the emission estimates (up to 50% for NOx, ~100% for NMVOC and ~1000% for CO). Application of the different emission inventories in three model simulations showed minor differences in both surface O3 in rather unpolluted areas in China and at higher altitudes (500mbar). In polluted areas, differences in surface O3 are 30-50% between the different model simulations which seem rather small taking into account the large differences in the emission inventories. Additional sensitivity runs showed that the difference in NOx emissions as well NMVOC emissions is a dominant factor which controls the differences in simulated O3 concentrations while the impact of differences in CO emissions is relatively small. Although the CO emission estimate by CORP seems to be underestimated, there is no confidence to highlight one emission inventory better than the others.
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Ma, J., and J. A. van Aardenne. "Impact of different emission inventories on simulated tropospheric ozone over China: a regional chemical transport model evaluation." Atmospheric Chemistry and Physics Discussions 4, no. 1 (2004): 507–32. http://dx.doi.org/10.5194/acpd-4-507-2004.
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Abstract. The importance of emission inventory uncertainty on the simulation of summertime tropospheric Ozone over China has been analyzed using a regional chemical transport model. Three independent emissions inventories, that are (i) emission estimates from the Emission Database for Global Atmospheric Research (EDGAR) for the year 1995, (ii) a regional emission inventory used in the Transport and Chemical Evolution over the Pacific (TRACE-P) program with emissions for the year 2000 and (iii) a national emission inventory used in the China Ozone Research Program (CORP) with emission estimates for the year 1995, are used for model simulation over a summer period. Methods used for the development of the inventories are discussed and differences in simulated ozone and its precursors with these emission inventories are analyzed. Comparison of the emission inventories revealed large differences in the emission estimates (up to 50% for NOx, ~100% for NMVOC and ~1000% for CO). Application of the different emission inventories in three model simulations showed minor differences in both surface O3 in rather unpolluted areas in China and at higher altitudes (500 mbar). In polluted areas, differences in surface O3 are 30-50% between the different model simulations which seems rather small taking into account the large differences in the emission inventories. Additional sensitivity runs showed that the difference in NOx emissions as well NMVOC emissions is a dominant factor which controls the differences in simulated O3 concentrations while the impact of differences in CO emissions is relatively small. Although the CO emission estimate by CORP seems to be underestimated, there is no confidence to highlight one emission inventory better than the others.
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Chen, Chao Hua, and Che Cheng Yeh. "Study on Inventory Policies for the On-Line Shopping Company with Quick Response Service." Applied Mechanics and Materials 411-414 (September 2013): 2251–57. http://dx.doi.org/10.4028/www.scientific.net/amm.411-414.2251.
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Nowadays, large-scale B2C online shopping platforms tend to move toward a business model that is characterized by large product variety and small amounts. They also cooperate with professional warehouse management providers who offer inventory services to achieve the business goal of fast delivery to consumers. Due to the fact that the merchandise on online shopping platforms is usually sold on consignment, these businesses strive for inventory cost minimization, optimal use of storage space, and efficient inventory management based on differences between product supply and demand patterns. This study establishes an online shopping platform with quick response service capability by employing a systematic simulation method. The replenishment mechanism between the supplier and the platform warehouse is based on vendor-managed inventory methods. An optimal inventory management strategy is obtained through a simulation optimization method for the following three variables: product storage ratio, reorder points, and warehouse capacity. The research results of this study show that by controlling the product storage ratio at fixed warehouse capacity and reorder points, the backorder rate can be reduced from 22.06% to 13.01. If equal attention is paid to product storage ratio, reorder points, and warehouse capacity, the backorder rate can be decreased to 0 and the supply chain costs of the platform can be reduced as well. This clearly indicates that this storage control model provides optimal utilization of the available resources of the online shopping platform and an efficient utilization of storage space to reduce shortages and operational costs and achieve the business goal of quick service.
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Jamali, Gholamreza, Shib Sankar Sana, and Reza Moghdani. "Hybrid improved cuckoo search algorithm and genetic algorithm for solving Markov-modulated demand." RAIRO - Operations Research 52, no. 2 (2018): 473–97. http://dx.doi.org/10.1051/ro/2017076.
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One of the fundamental problems in supply chain management is to design the effective inventory control policies for models with stochastic demands because efficient inventory management can both maintain a high customers’ service level and reduce unnecessary over and under-stock expenses which are significant key factors of profit or loss of an organization. In this study, a new formulation of an inventory system is analyzed under discrete Markov-modulated demand. We employ simulation-based optimization that combines simulated annealing pattern search and ranking selection (SAPS&RS) methods to approximate near-optimal solutions of this problem. After determining the values of demand, we employ novel approach to achieve minimum cost of total SCM (Supply Chain Management) network. In our proposed approach, hybrid improved cuckoo search algorithm (ICS) and genetic algorithm (GA) are presented as main platform to solve this problem. The computational results demonstrate the effectiveness and applicability of the proposed approach.
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Tao, Jiang, Ahmad Hassan, Chen Qibing, et al. "Psychological and Physiological Relaxation Induced by Nature-Working with Ornamental Plants." Discrete Dynamics in Nature and Society 2020 (March 7, 2020): 1–7. http://dx.doi.org/10.1155/2020/6784512.
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Objective. Nature has a significant impact on general well-being. However, till date, little psychophysiological evidence is available on the benefits of nature-based activities in adults. The primary goal of this study was to determine the physiological and psychological benefits of horticultural activity in adults. The participants were instructed to perform the making of a flower basket (horticultural activity) and a computer task (i.e., control activity) was compared. Methods. A total of 40 Chinese females (mean age 22.2 ± 0.9 years) participated in this experiment. The Blood pressure, the State-Trait Anxiety Inventory (STAI), and the electroencephalograms (EEGs) were used to measure the participants’ psychophysiological responses. Results. Analysis of the STAI data showed a lower anxiety score after performing the horticultural activity than after performing the control activity. Furthermore, in the EEG evaluation, variations in the brainwaves were observed after both activities. Conclusions. The study results suggest that horticultural activity induced physiological and psychological relaxation in adults.
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Laurensia, Venna, Gusti Noorrizka Veronika Achmad, Raswita Diniya, and Ivonne Soeliono. "Evaluasi Perencanaan Persediaan Antibiotik Secara Kuantitatif Di Instalasi Farmasi Rumah Sakit Tipe A." JURNAL MANAJEMEN DAN PELAYANAN FARMASI (Journal of Management and Pharmacy Practice) 10, no. 3 (2020): 176. http://dx.doi.org/10.22146/jmpf.49035.
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Planning an inventory of antibiotics that are not good will cause problems in planning, which are over-supply of antibiotics (stagnant) and lack of antibiotic stock (stockout). In this study an quantitative evaluation of antibiotic inventory planning was carried out using the Economic Order Quantity (EOQ) and Maximum-Minimum Stock Level (MMSL) control methods in 2017 at Type A Hospital’s Pharmacy Department. The EOQ method aims to minimize the number of orders while the MMSL method is used to determine the minimum and maximum stock of antibiotics that must be ordered. The results were compared with the need for 2018 then calculations are carried out to determine the amount of stagnant and stockout antibiotics. The number of antibiotics that were stagnant by EOQ method simulation was 44.73% and by MMSL method was 48.02%, while the number of antibiotics stocked by EOQ method was 38.15% and by MMSL method was 42.76%. The category of antibiotic supplies in 2018 in real terms which was included in a stagnant state was 23.68%, stockout ie 55.26% of 152 antibiotics. Evaluation of antibiotic inventory planning using the EOQ method results in the calculation of lower order quantities while the number of orders with MMSL is higher. To find out more broadly about the evaluation of inventory planning in the hospital needed further research by taking into account all drugs not just antibiotics.
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Johannessen, E., T. Davies, A. Valeriano, E. Blackmore, A. Belyea, and F. Gilic. "LO77: Performance enhancing psychological skills in clinical simulation." CJEM 22, S1 (2020): S35. http://dx.doi.org/10.1017/cem.2020.131.
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Introduction: Clinical simulations in are designed to evoke feelings of stress and uncertainty in order to mimic challenges that learners will face in the real world. When not managed properly, these sources of extraneous cognitive load cause a burden on working memory, leading to a hindered ability to acquire new information. The “Beat the Stress Fool” (BTSF) protocol is a performance-enhancing tool designed to reduce cognitive overload during acute care scenarios. It involves breathing exercises, positive self-talk, visualization, and deliberate articulations. This study aims to validate the BTSF protocol as a method for reducing cognitive load using both psychometric and physiologic measures. Methods: Data collection took place during the Queen's University “Nightmares-FM” course. This clinical simulation program involves team-based scenarios designed to teach the fundamentals of acute care to first-year family medicine residents. Participants were divided equally into experimental and control groups based on pre-existing cohorts. Participants completed a baseline state-trait anxiety inventory and a demographics survey. The experimental group was guided through the BTSF protocol prior to each of 16 simulations; in both groups, physiologic and psychometric cognitive load measurements were collected for the alternating team leader. Galvanic skin response (GSR) and heart rate (HR) were collected during a 15-second baseline and throughout each simulation using a Shimmer 3 GSR+ wearable sensor. Self-reported cognitive load was assessed after each scenario using the 9-point Paas scale. Results: The mean Paas scores for the BTSF group were significantly lower than the control group (6.2 vs 6.9, p < 0.05), indicating lower subjective cognitive load. GSR signal magnitude (p = 0.086), spike amplitude (p = 0.066), and spike density (p = 0.584) were also lower in the BTSF group. There was no difference in HR between groups. There was not a significant correlation between self-reported cognitive load and the normalized physiologic measures. Conclusion: The results demonstrate the effectiveness of the BTSF protocol in lowering the amount of perceived mental effort required to perform clinical simulation tasks. These findings were mirrored in the galvanic skin response signal, though our study was likely underpowered for significance. This is the first study to validate a proof-of-concept for the BTSF protocol in learners during simulated training.
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van Tetering, Anne AC, Jacqueline LP Wijsman, Sophie EM Truijens, Annemarie F. Fransen, M. Beatrijs van der Hout-van der Jagt, and S. Guid Oei. "Comparison of the psychological and physiological effects on students of a video-assisted or text introduction to a simulated task." BMJ Simulation and Technology Enhanced Learning 5, no. 2 (2018): 96–101. http://dx.doi.org/10.1136/bmjstel-2017-000272.
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IntroductionThe use of different methods for introducing the scenario in simulation-based medical education has not been investigated before and may be a useful element to optimise the effectiveness of learning. The aim of this study was to compare an immersive video-assisted introduction to a minimal text-based one, with regard to emotional assessment of the situation.MethodsIn this pilot study, 39 students participated in a medical simulated scenario. The students were randomly assigned to an experimental group (video-assisted introduction) or a control group (minimal textual introduction) and both were followed by performing surgery on LapSim (Surgical Science, Gothenburg, Sweden). The emotional assessment of the situation, cognitive appraisal, was defined as the ratio of the demands placed by an individual’s environment (primary appraisal) to that person’s resources to meet the demands (secondary appraisal). Secondary outcomes were anxiety (State-Trait Anxiety Inventory), physiological parameters (heart rate, heart rate variability, skin conductance, salivary cortisol), engagement (Game Engagement Questionnaire), motivation (Intrinsic Motivation Inventory) and performance (mean score in percentage calculated by LapSim of predefined levels).ResultsParticipants in the immersive video group (n=17) were overloaded in terms of their perceived demands (a ratio of 1.17, IQR 0.30) compared with those in the control group (a ratio of 1.00, IQR 0.42, n=22) (P=0.01). No significant differences were found between the groups in secondary outcomes. Both groups showed an increase of anxiety after the introduction method. In the experimental group, this score increased from 9.0 to 11.0, and in the textual group from 7.5 to 10.5, both P<0.01.DiscussionThis study shows that the method of introducing a simulated scenario may influence the emotional assessment of the situation. It may be possible to make your simulation introduction too immersive or stimulating, which may interfere with learning. Further research will be necessary to investigate the impact and usefulness of these findings on learning in simulation-based medical education.
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Abolnikov, Lev, and Jewgeni H. Dshalalow. "A first passage problem and its applications to the analysis of a class of stochastic models." Journal of Applied Mathematics and Stochastic Analysis 5, no. 1 (1992): 83–97. http://dx.doi.org/10.1155/s1048953392000066.
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A problem of the first passage of a cumulative random process with generally distributed discrete or continuous increments over a fixed level is considered in the article as an essential part of the analysis of a class of stochastic models (bulk queueing systems, inventory control and dam models).Using direct probability methods the authors find various characteristics of this problem: the magnitude of the first excess of the process over a fixed level, the shortage before the first excess, the levels of the first and pre-first excesses, the index of the first excess and others. The results obtained are illustrated by a number of numerical examples and then are applied to a bulk queueing system with a service delay discipline.
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Caballero-Morales, Santiago-Omar. "Development of a coded suite of models to explore relevant problems in logistics." PeerJ Computer Science 6 (November 30, 2020): e329. http://dx.doi.org/10.7717/peerj-cs.329.
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Logistics is the aspect of the supply chain which is responsible of the efficient flow and delivery of goods or services from suppliers to customers. Because a logistic system involves specialized operations such as inventory control, facility location and distribution planning, the logistic professional requires mathematical, technological and managerial skills and tools to design, adapt and improve these operations. The main research is focused on modeling and solving logistic problems through specialized tools such as integer programing and meta-heuristics methods. In practice, the use of these tools for large and complex problems requires mathematical and computational proficiency. In this context, the present work contributes with a coded suite of models to explore relevant problems by the logistic professional, undergraduate/postgraduate student and/or academic researcher. The functions of the coded suite address the following: (1) generation of test instances for routing and facility location problems with real geographical coordinates; (2) computation of Euclidean, Manhattan and geographical arc length distance metrics for routing and facility location problems; (3) simulation of non-deterministic inventory control models; (4) importing/exporting and plotting of input data and solutions for analysis and visualization by third-party platforms; and (5) designing of a nearest-neighbor meta-heuristic to provide very suitable solutions for large vehicle routing and facility location problems. This work is completed by a discussion of a case study which integrates the functions of the coded suite.
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Zhong, Hui, Yu Zhao, Marilena Muntean, Lei Zhang, and Jie Zhang. "A high-resolution regional emission inventory of atmospheric mercury and its comparison with multi-scale inventories: a case study of Jiangsu, China." Atmospheric Chemistry and Physics 16, no. 23 (2016): 15119–34. http://dx.doi.org/10.5194/acp-16-15119-2016.
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Abstract. A better understanding of the discrepancies in multi-scale inventories could give an insight into their approaches and limitations as well as provide indications for further improvements; international, national, and plant-by-plant data are primarily obtained to compile those inventories. In this study we develop a high-resolution inventory of Hg emissions at 0.05° × 0.05° for Jiangsu, China, using a bottom-up approach and then compare the results with available global/national inventories. With detailed information on individual sources and the updated emission factors from field measurements applied, the annual Hg emissions of anthropogenic origin in Jiangsu in 2010 are estimated at 39 105 kg, of which 51, 47, and 2 % were Hg0, Hg2+, and Hgp, respectively. This provincial inventory is thoroughly compared to three downscaled national inventories (NJU, THU, and BNU) and two global ones (AMAP/UNEP and EDGARv4.tox2). Attributed to varied methods and data sources, clear information gaps exist in multi-scale inventories, leading to differences in the emission levels, speciation, and spatial distributions of atmospheric Hg. The total emissions in the provincial inventory are 28, 7, 19, 22, and 70 % larger than NJU, THU, BNU, AMAP/UNEP, and EDGARv4.tox2, respectively. For major sectors, including power generation, cement, iron and steel, and other coal combustion, the Hg contents (HgC) in coals/raw materials, abatement rates of air pollution control devices (APCDs) and activity levels are identified as the crucial parameters responsible for the differences in estimated emissions between inventories. Regarding speciated emissions, a larger fraction of Hg2+ is found in the provincial inventory than national and global inventories, resulting mainly from the results by the most recent domestic studies in which enhanced Hg2+ were measured for cement and iron and steel plants. Inconsistent information on large power and industrial plants is the main source of differences in spatial distribution of emissions between the provincial and other inventories, particularly in southern and northwestern Jiangsu, where intensive coal combustion and industry are located. Quantified with Monte Carlo simulation, uncertainties in the provincial inventory are smaller than those of the NJU national inventory, resulting mainly from the more accurate activity data of individual plants and the reduced uncertainties in HgC in coals/raw materials.
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Chen, Heping, Ning Xi, Weihua Sheng, and Yifan Chen. "General Framework of Optimal Tool Trajectory Planning for Free-Form Surfaces in Surface Manufacturing." Journal of Manufacturing Science and Engineering 127, no. 1 (2005): 49–59. http://dx.doi.org/10.1115/1.1828057.
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Surface manufacturing is a process of adding material to or removing material from the surfaces of a part. Spray painting, spray forming, rapid tooling, spray coating, and polishing are some of the typical applications of surface manufacturing, where industrial robots are usually used. Tool planning for industrial robots in surface manufacturing is a challenging research topic. Typical teaching methods are not affordable any more because products are subject to a shorter product life, frequent design changes, small lot sizes, and small in-process inventory restrictions. An automatic tool trajectory planning process is hence desirable for tool trajectory planning of industrial robots. Based on the computer-aided design model of a part, the tool model, task constraints, and optimization criteria, a general framework of optimal tool trajectory planning in surface manufacturing is developed. Optimal tool trajectories are generated by approximately solving a multiobjective optimization problem. To test if the generated trajectory satisfies the given constraints, a trajectory verification model is developed. Simulations are performed to determine if the given constraints are satisfied. Simulation results show that the optimal tool trajectory planning framework can be applied to generate trajectories for a variety of applications in surface manufacturing. This general framework can also be extended to other applications such as dimensional inspection and demining.
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Bate, Marie-Thérèse, Bruno Speleers, Luc A. M. L. Vakaet, and Wilfried J. De Neve. "Quality control and error detection in the radiotherapy treatment process." Journal of Radiotherapy in Practice 1, no. 3 (1999): 125–34. http://dx.doi.org/10.1017/s1460396999000217.
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Purpose: In 1995, a post of quality control (QC) officer was established in the Radiotherapy Department of the University Hospital Gent (R-UZG). We report here the evolution of error detection in the domain of information transfer during the different steps of the treatment chain, in our department, since the creation of this job.Material and Methods: From January 1995 to December 1997 (1995 n = 831; 1996: n = 1095; 1997: n = 1091), data on errors were recorded. At the start, an inventory was made of the existing situation and a Quality Assurance (QA) program was outlined for process control. According to the site of origin of errors in the treatment preparation chain, errors were separated into five levels: medical treatment prescription, simulation, treatment planning, treatment data transfer and daily set-up.Results: The total number of errors found was 459 in 1995; 809 in 1996 and 1046 in 1997. During 1995 and 1996 the medical prescription protocols were adapted to the increasing need of the radiation technologists for more information. This explains an increased number of errors (from 80/459 to 276/809) in 1996. After a period of adaptation, the number of errors decreased in 1997 (257/1046). The second level, where many errors were found, is at the transfer phase (1995: 181/459 1996: 210/809; 1997: 336/1046). Most of these errors were made during the transfer of data from the prescription chart to the computer. These errors were due to lack of attention, human mistakes and calculation errors. The number of errors during simulation increased due to rotation of personnel in 1996. The increase persisted in 1997 for the same reason. Transfer errors due to the automatic transfer of leaf settings decreased (1995:18/29; 1996:15/17; 1997:7/31) Thanks to the start of QC management, errors were detected and corrected in the entire treatment process at R-UZG. Once changes were accepted, new challenges were initiated. After each evaluation, initiatives were taken to try to decrease specific errors. Changing attitudes was a difficult and slow process, but progress was made. The most important change in attitude certainly was the acceptation of the concept of QC.
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Kalabokidis, Kostas, Alan Ager, Mark Finney, Nikos Athanasis, Palaiologos Palaiologou, and Christos Vasilakos. "AEGIS: a wildfire prevention and management information system." Natural Hazards and Earth System Sciences 16, no. 3 (2016): 643–61. http://dx.doi.org/10.5194/nhess-16-643-2016.
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Abstract. We describe a Web-GIS wildfire prevention and management platform (AEGIS) developed as an integrated and easy-to-use decision support tool to manage wildland fire hazards in Greece (http://aegis.aegean.gr). The AEGIS platform assists with early fire warning, fire planning, fire control and coordination of firefighting forces by providing online access to information that is essential for wildfire management. The system uses a number of spatial and non-spatial data sources to support key system functionalities. Land use/land cover maps were produced by combining field inventory data with high-resolution multispectral satellite images (RapidEye). These data support wildfire simulation tools that allow the users to examine potential fire behavior and hazard with the Minimum Travel Time fire spread algorithm. End-users provide a minimum number of inputs such as fire duration, ignition point and weather information to conduct a fire simulation. AEGIS offers three types of simulations, i.e., single-fire propagation, point-scale calculation of potential fire behavior, and burn probability analysis, similar to the FlamMap fire behavior modeling software. Artificial neural networks (ANNs) were utilized for wildfire ignition risk assessment based on various parameters, training methods, activation functions, pre-processing methods and network structures. The combination of ANNs and expected burned area maps are used to generate integrated output map of fire hazard prediction. The system also incorporates weather information obtained from remote automatic weather stations and weather forecast maps. The system and associated computation algorithms leverage parallel processing techniques (i.e., High Performance Computing and Cloud Computing) that ensure computational power required for real-time application. All AEGIS functionalities are accessible to authorized end-users through a web-based graphical user interface. An innovative smartphone application, AEGIS App, also provides mobile access to the web-based version of the system.
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K.T., Vinod, S. Prabagaran, and O. A. Joseph. "Dynamic due date assignment method." Journal of Manufacturing Technology Management 30, no. 6 (2019): 987–1003. http://dx.doi.org/10.1108/jmtm-06-2017-0112.
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Purpose The purpose of this paper is to determine the interaction between dynamic due date assignment methods and scheduling decision rules in a typical dynamic job shop production system in which setup times are sequence dependent. Two due date assignment methods and six scheduling rules are considered for detailed investigation. The scheduling rules include two new rules which are modifications of the existing rules. The performance of the job shop system is evaluated using various measures related to flow time and tardiness. Design/methodology/approach A discrete-event simulation model is developed to describe the operation of the job shop. The simulation results are subjected to statistical analysis based on the method of analysis of variance. Regression-based analytical models have been developed using the simulation results. Since the due date assignment methods and the scheduling rules are qualitative in nature, they are modeled using dummy variables. The validation of the regression models involves comparing the predictions of the performance measures of the system with the results obtained through simulation. Findings The proposed scheduling rules provide better performance for the mean tardiness measure under both the due date assignment methods. The regression models yield a good prediction of the performance of the job shop. Research limitations/implications Other methods of due date assignment can also be considered. There is a need for further research to investigate the performance of due date assignment methods and scheduling rules for the experimental conditions that involve system disruptions, namely, breakdowns of machines. Practical implications The explicit consideration of sequence-dependent setup time (SDST) certainly enhances the performance of the system. With appropriate combination of due date assignment methods and scheduling rules, better performance of the system can be obtained under different shop floor conditions characterized by setup time and arrival rate of jobs. With reductions in mean flow time and mean tardiness, customers are benefitted in terms of timely delivery promises, thus leading to improved service level of the firm. Reductions in manufacturing lead time can generate numerous other benefits, including lower inventory levels, improved quality, lower costs, and lesser forecasting error. Originality/value Two modified scheduling rules for scheduling a dynamic job shop with SDST are proposed. The analysis of the dynamic due date assignment methods in a dynamic job shop with SDST is a significant contribution of the present study. The development of regression-based analytical models for a dynamic job shop operating in an SDST environment is a novelty of the present study.
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Vlasenko, Dmitry, and Roland Kasper. "A New Software Approach for the Simulation of Multibody Dynamics." Journal of Computational and Nonlinear Dynamics 2, no. 3 (2007): 274–78. http://dx.doi.org/10.1115/1.2734182.
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This paper introduces a new modular software approach combining symbolical and numerical methods for the simulation of the dynamics of mechanical systems. It is based on an exact, noniterative object-oriented algorithm, which is applicable to mechanisms with any joint type and any topology, including branches and kinematic loops. The simulation of big well-partitioned systems has complexity O(N), where N is the total number of simulated bodies. A new design software Virtual System Designer (VSD) integrates this method with the three-dimensional computer aided design tool Autodesk Inventor, which minimizes the cost of the development of models and the training of design engineers. The most time-expensive routine of the simulation process in VSD is the calculation of the accelerations of each body, which needs to find the roots of matrix equations. Accounting for the sparsity of matrices can significantly improve the numerical efficiency of the routine. The preprocessing module, developed using Maple software, performs the symbolic simplification of the matrix multiplication’s and QR decomposition’s procedures. The new coordinate projection method is demonstrated. The results of the simulation of the dynamics of a double insulator chain example show the method’s stability and effectiveness.
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Kalabokidis, K., A. Ager, M. Finney, N. Athanasis, P. Palaiologou, and C. Vasilakos. "AEGIS: a wildfire prevention and management information system." Natural Hazards and Earth System Sciences Discussions 3, no. 10 (2015): 6185–228. http://dx.doi.org/10.5194/nhessd-3-6185-2015.
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Abstract. A Web-GIS wildfire prevention and management platform (AEGIS) was developed as an integrated and easy-to-use decision support tool (http://aegis.aegean.gr). The AEGIS platform assists with early fire warning, fire planning, fire control and coordination of firefighting forces by providing access to information that is essential for wildfire management. Databases were created with spatial and non-spatial data to support key system functionalities. Updated land use/land cover maps were produced by combining field inventory data with high resolution multispectral satellite images (RapidEye) to be used as inputs in fire propagation modeling with the Minimum Travel Time algorithm. End users provide a minimum number of inputs such as fire duration, ignition point and weather information to conduct a fire simulation. AEGIS offers three types of simulations; i.e. single-fire propagations, conditional burn probabilities and at the landscape-level, similar to the FlamMap fire behavior modeling software. Artificial neural networks (ANN) were utilized for wildfire ignition risk assessment based on various parameters, training methods, activation functions, pre-processing methods and network structures. The combination of ANNs and expected burned area maps produced an integrated output map for fire danger prediction. The system also incorporates weather measurements from remote automatic weather stations and weather forecast maps. The structure of the algorithms relies on parallel processing techniques (i.e. High Performance Computing and Cloud Computing) that ensure computational power and speed. All AEGIS functionalities are accessible to authorized end users through a web-based graphical user interface. An innovative mobile application, AEGIS App, acts as a complementary tool to the web-based version of the system.
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Barbosa Torres, Carlos, Sixto Cubo Delgado, and Florencio Vicente Castro. "SIMULACIÓN DE SÍNTOMAS EN PACIENTES CON FIBROMIALGIA." International Journal of Developmental and Educational Psychology. Revista INFAD de Psicología. 2, no. 1 (2017): 571. http://dx.doi.org/10.17060/ijodaep.2017.n1.v2.967.
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Abstract.SIMULATION OF SYMPTOMS IN PATIENTS WITH FIBROMYALGIAIn this paper we find a study about the variable of simulation of symptoms in fibromyalgia syndrome regarding to other psychological variables such as quality of life, depression, anxiety as well as gradation of pain. The study was performed with 40 patients, all diagnosed with fibromyalgia by the criteria of the American Rheumatology Association. The instruments used were the Structured Inventory of Malingered Symptomatology (SIMS), the Graded Chronic Pain Scale and SF-36 Health Survey (SF-36v2). The results show that there is a relationship between the simulation of symptoms and chronic pain but not with quality of life. The simulation of symptoms in patients with fibromyalgia is a very complex phenomenon that depends on several methods of control among which it is possible to emphasize the use of screening like the SIMS supported with important physical and psychological examinations by experts.Key words: Fibromyalgia, chronic pain, symptom simulation.Resumen.En el presente trabajo encontramos un estudio sobre la variable simulación de síntomas en pacientes con fibromialgia en relación con otras variables psicológicas como calidad de vida, depresión y ansiedad al igual que la gradación del dolor. El estudio se realizó con un total de 40 pacientes todos diagnosticados con fibromialgia por los criterios de la Asociación Americana de Reumatología. Los instrumentos utilizados fueron, el Inventario Estructurado de Simulación de síntomas (SIMS), el Graded Chronic Pain Scale y el SF-36 Health Survey (SF-36v2) o Cuestionario autogestionado de Salud SF-36. Los resultados expuestos muestran que existen relación entre la simulación de síntomas dolor crónico pero no con la calidad de vida. La simulación de síntomas en pacientes con fibromialgia es un fenómeno muy complejo que depende de varios métodos de control entre los que cabe destacar la utilización de screening como el SIMS apoyados con importantes exámenes físicos y psicológicos por expertos.Palabras clave: Fibromialgia, dolor crónico, simulación de síntomas.
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Laurindo, Quézia Manuela Gonçalves, Túlio Almeida Peixoto, and João José de Assis Rangel. "Communication mechanism of the discrete event simulation and the mechanical project softwares for manufacturing systems." Journal of Computational Design and Engineering 6, no. 1 (2018): 70–80. http://dx.doi.org/10.1016/j.jcde.2018.02.005.
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Abstract This paper presents an integration mechanism for online communication between a discrete event simulation (DES) software and a system dynamics (SD) software. The integration between them allowed executing a hybrid and broader simulation, in which the complexity of the systems and their multi-faceted relationships may demand the combination of different simulation methods and the synergies between the techniques. The Ururau free and open-source software (FOSS) was applied to implement the DES model. In order to build the dynamic model, we used the software for mechanical design called CAD 3D Software Inventor®. Besides, we also employed the DES model in the test step of a control system in real time. The results of that mechanism implementation enabled the evaluation of different aspects of a typical manufacturing system. Furthermore, the integration between the control system and the DES model allowed validating the logic of the programmable logic controller (PLC). Highlights Mechanism for online communication between a discrete event simulation (DES) software and a system dynamics (SD) software. A free and open-source software (FOSS) was applied to implement the DES model. The results of that mechanism implementation enabled the evaluation of different aspects of a typical manufacturing system.
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Sytnik, P., A. Hussain, and J. Brooks. "P129: The impact of high performance physician training on resident wellness and clinical performance." CJEM 18, S1 (2016): S121. http://dx.doi.org/10.1017/cem.2016.303.
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Introduction / Innovation Concept: There are numerous research studies in the medical literature, which demonstrate how the experience of a medical residency can contribute towards burnout. The escalating performance pressures and expectations during residency training have the potential to negatively impact upon physician health and clinical performance. The purpose of this prospective cohort study was to test the effectiveness of the High Performance Physician (HPP) program among General Surgery residents at the University of Manitoba with regard to burnout and clinical performance. Methods: This program was delivered over a 9-week period. All 26 residents were asked to complete the Maslach Burnout Inventory - Human Services Survey (MBI-HSS). Each resident then participated as the team leader for a 15-minute trauma resuscitation simulation. Three attending physicians from Surgery & Emergency Medicine assessed resident performance and ability to manage work-based stressors. Following the simulation, each resident received a debrief interview. Once the HPP curriculum had been completed, residents took part in a second high fidelity simulation session and again completed the MBI-HSS. Curriculum, Tool, or Material: The HPP program offered through the Department of Emergency Medicine (EM), is a performance enhancement based curriculum. It is designed to equip physicians with mental skills to help optimize focus, arousal control, stress management, communication, and teamwork. Further, to utilize these skills to cope and respond more effectively to the inherent performance pressures that may present within one’s area of specialization. Conclusion: The Emotional Exhaustion domain of the MBI-HSS demonstrated a statistically significant decrease. The other domain scores were not statistically significant. Simulation domain scores did not demonstrate a statistically significant difference in performance between the pre- and post-HPP curriculum simulation sessions. A summative content analysis of the interview data demonstrated that residents believed internal barriers to situational awareness were the most significant impact on performance. Further study is required to determine if differences are seen in long-term follow-up.
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Howlett, M., M. Mostofa, J. Talbot, J. Fraser, and P. Atkinson. "P065: Emergency department staff perceived need and preferred methods for communication skills training." CJEM 21, S1 (2019): S86—S87. http://dx.doi.org/10.1017/cem.2019.256.
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Introduction: Burnout includes emotional exhaustion (EE), depersonalization (DP) and personal accomplishment (PA). Emergency Department (ED) staff have high levels of burnout that may be responsive to communication skills training. We surveyed ED staff perception of need and efficacy before and after an intervention using an established conflict resolution methodology. Methods: ED physicians, nurses and support staff were surveyed at two regional hospitals using the Maslach Burnout Inventory (MBI) and a communications questionnaire to establish the perceived need for communication skill training. Participants from one center were provided with a communications intervention (Crucial Conversations®, VitalSmarts®), and a refresher course 6-15 months later. The survey was then repeated at both sites and course participant feedback was elicited. Results: MBI results were high (mean EE = 25.25 (high &gt; 25), 95% CI = 22.5-28; DP = 11.6 (high &gt; 8), 95% CI = 10.1-13.2; PA = 35.85 (low &lt;34), 95% CI = 34.3-37.4). Initially 82% of intervention and 77% of control site participants responded that “attending an educational session about ways to communicate better would help the participants at work”. Post intervention group responses to “The program will be helpful to me in communicating more effectively in my work environment” were: 75% “strongly agree” and 25% “agree”. No rating below “agree” was assigned by any of the participants. Participants preferred facilitated small group simulations and advocated for earlier career implementation. Conclusion: There was a perceived need for and impact from communication skills training for ED staff with high measured burnout. Training may be best implemented in small group simulated encounters and in health professional education curriculum or as part of work orientation.
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Jordan, Victoria S. "Systems engineering in health care: Overview and examples from The University of Texas MD Anderson Cancer Center." Journal of Clinical Oncology 30, no. 34_suppl (2012): 140. http://dx.doi.org/10.1200/jco.2012.30.34_suppl.140.
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140 Background: The University of Texas has six health institutions and Industrial and Systems Engineering faculty throughout university locations across the state. These academic medical centers, including MD Anderson Cancer Center, and schools of engineering, business, and medicine are partnering to implement Systems Engineering in healthcare throughout the UT system. The “systems approach to implementing Systems Engineering” is an opportunity to serve as a world-class model for collaboration across academic institutions for engineering, business, medicine, and healthcare organizations to implement Systems Engineering and systems thinking in healthcare. The objective of the collaboration is not just to produce successful projects, but to achieve transformational change. Methods: This presentation will provide an overview of Systems Engineering and provide examples of the different tools and strategies from the discipline including lean, six sigma, mathematical simulation, optimization and operations research, human factors, facility design layout, statistical process control, design of experiments, scheduling, supply chain and inventory management, staffing models, etc. Funding, leadership, training, and communication efforts associated with the effort will be reviewed including the grant application process for transformational efforts. (The implementation follows the PDSA process.) Results: Currently nine grants have been awarded in the UT system for implementing Systems Engineering. Results will be shared (in terms of cost savings and/or avoidance and patient satisfaction) from specific projects such as a lean effort in the Diagnostic Center and simulation models to schedule nurses in the OR and to determine resource requirements in the ICU. Conclusions: Systems Engineering is a valuable discipline that is relatively new to healthcare. Practicing clinical oncologists can increase efficiency, patient flow, and patient and physician satisfaction by applying Systems Engineering tools and strategies.
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Kljajić, Miroljub, Andrej Škraba, and Igor Bernik. "Adaptive Inventory Control Simulation Model." IFAC Proceedings Volumes 33, no. 12 (2000): 163–66. http://dx.doi.org/10.1016/s1474-6670(17)37299-3.
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Alstrøm, Poul, and Per Madsen. "Simulation of inventory control systems." International Journal of Production Economics 26, no. 1-3 (1992): 125–34. http://dx.doi.org/10.1016/0925-5273(92)90054-b.
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Wang, Pei, Xiaozheng Gan, Qing Zhang, et al. "Analysis of Parameters for the Accurate and Fast Estimation of Tree Diameter at Breast Height Based on Simulated Point Cloud." Remote Sensing 11, no. 22 (2019): 2707. http://dx.doi.org/10.3390/rs11222707.
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Terrestrial laser scanning (TLS) is a high-potential technology in forest surveys. Estimating the diameters at breast height (DBH) accurately and quickly has been considered a key step in estimating forest structural parameters by using TLS technology. However, the accuracy and speed of DBH estimation are affected by many factors, which are classified into three groups in this study. We adopt an additive error model and propose a simple and common simulation method to evaluate the impacts of three groups of parameters, which include the range error, angular errors in the vertical and horizontal directions, angular step width, trunk distance, slice thickness, and real DBH. The parameters were evaluated statistically by using many simulated point cloud datasets that were under strict control. Two typical circle fitting methods were used to estimate DBH, and their accuracy and speed were compared. The results showed that the range error and the angular error in horizontal direction played major roles in the accuracy of DBH estimation, the angular step widths had a slight effect in the case of high range accuracy, the distance showed no relationship with the accuracy of the DBH estimation, increasing the scanning angular width was relatively beneficial to the DBH estimation, and the algebraic circle fitting method was relatively fast while performing DBH estimation, as is the geometrical method, in the case of high range accuracy. Possible methods that could help to obtain accurate and fast DBH estimation results were proposed and discussed to optimize the design of forest inventory experiments.
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Lindley, Celeste, and John Mackowiak. "Methods of inventory control." American Journal of Health-System Pharmacy 42, no. 1 (1985): 122–28. http://dx.doi.org/10.1093/ajhp/42.1.122.
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Yang, Yang, and Yu Zhao. "Quantification and evaluation of atmospheric pollutant emissions from open biomass burning with multiple methods: a case study for the Yangtze River Delta region, China." Atmospheric Chemistry and Physics 19, no. 1 (2019): 327–48. http://dx.doi.org/10.5194/acp-19-327-2019.
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Abstract. Air pollutant emissions from open biomass burning (OBB) in the Yangtze River Delta (YRD) were estimated for 2005–2015 using three (traditional bottom-up, fire radiative power (FRP), and constraining) approaches, and the differences among those methods and their sources were analyzed. The species included PM10, PM2.5, organic carbon (OC), elemental carbon (EC), CH4, non-methane volatile organic compounds (NMVOCs), CO, CO2, NOx, SO2 and NH3. The interannual trends in emissions with FRP-based and constraining methods were similar to the fire counts in 2005–2012, while those with the traditional method were not. For most years, emissions of all species estimated with the constraining method were smaller than those with the traditional method except for NMVOCs, while they were larger than those with the FRP-based method except for EC, CH4 and NH3. Such discrepancies result mainly from different masses of crop residue burned in the field (CRBF) estimated in the three methods. Chemistry transport modeling (CTM) was applied using the three OBB inventories. The simulated PM10 concentrations with constrained emissions were closest to the available observations, implying that the constraining method provided the best emission estimates. CO emissions in the three methods were compared with other studies. Similar temporal variations were found for the constrained emissions, FRP-based emissions, GFASv1.0 and GFEDv4.1s, with the largest and the lowest emissions estimated for 2012 and 2006, respectively. The temporal variations in the emissions based on the traditional method, GFEDv3.0, and the method of Xia et al. (2016) were different. The constrained CO emissions in this study were commonly smaller than those based on the traditional bottom-up method and larger than those based on burned area or FRP in other studies. In particular, the constrained emissions were close to GFEDv4.1s that contained emissions from small fires. The contributions of OBB to two particulate pollution events in 2010 and 2012 were analyzed with the brute-force method. Attributed to varied OBB emissions and meteorology, the average contribution of OBB to PM10 concentrations in 8–14 June 2012 was estimated at 37.6 % (56.7 µg m−3), larger than that in 17–24 June 2010 at 21.8 % (24.0 µg m−3). Influences of diurnal curves of OBB emissions and meteorology on air pollution caused by OBB were evaluated by designing simulation scenarios, and the results suggested that air pollution caused by OBB would become heavier if the meteorological conditions were unfavorable and that more attention should be paid to the OBB control at night. Quantified with Monte Carlo simulation, the uncertainty of the traditional bottom-up inventory was smaller than that of the FRP-based one. The percentages of CRBF and emission factors were the main source of uncertainty for the two approaches. Further improvement on CTM for OBB events would help better constrain OBB emissions.
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Conte, Giuseppe, and Paris Pennesi. "INVENTORY CONTROL BY MODEL PREDICTIVE CONTROL METHODS." IFAC Proceedings Volumes 38, no. 1 (2005): 85–90. http://dx.doi.org/10.3182/20050703-6-cz-1902.01498.
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Battaglia, F., M. Merlano, C. Sayed, M. McConnell, C. Ramnanan, and N. Rastogi. "P011: A pre-clerkship procedural curriculum designed for the future of Canadian medical education: a pilot and feasibility study." CJEM 21, S1 (2019): S67. http://dx.doi.org/10.1017/cem.2019.202.
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Introduction: Procedural skills training varies significantly across Canadian medical schools, and there is currently no standardized assessment tool to evaluate its benefits. This project aims to develop a curriculum that teaches 2nd-year medical students to perform and evaluate procedural skills. The goals of this program include decreasing anxiety, increasing confidence, and achieving competence for students and also allowing staff to judge the appropriate level of supervision when delegating learners to perform basic procedures in the team setting. Our curriculum incorporates, near-peer teaching as well as near peer formative assessment. Methods: Each of the twelve 2nd year participants completed a State Trait Anxiety Inventory and self-reported confidence questionnaire related to procedural skills. Students participated in four sessions taught by expert physicians over a five month period. A new skill was taught at each monthly workshop and an opportunity to practice previously taught skills was provided. Skills were assessed in a skills integration simulation OSCE, and the anxiety and confidence questionnaire was repeated. Results: Students who completed this pilot program showed a significant decrease in mean anxiety state (2.48 vs 1.74, p-value &lt;0.001), while the control group did not (p-value = 0.408). When assessing confidence, students who completed this program showed increased self-assessed knowledge and confidence in each of the program's assessed skills. An increased level of competency was achieved in each skill by each student as assessed by the expert physicians. Conclusion: There is evidence to suggest that implementation of this procedural skills training model within the Canadian medical school curriculum may improve student anxiety, confidence, and competency for success in clerkship and could be the foundation for developing milestones for EPAs.
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Istomina, Alena Andreevna, and Andrey Leonidovich Istomin. "SIMULATION IN INVENTORY PROBLEMS." Modern Technologies and Scientific and Technological Progress 2018, no. 1 (2020): 67–68. http://dx.doi.org/10.36629/2686-9896-2020-2018-1-67-68.
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The application of simulation methods in the problems of inventory management is
 shown. Machine simulation includes the problem formulation, model building, preparation of a computer
 program, an assessment of the reliability and realism of the process under study, analysis of results and
 decision-making.
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Esmali Ouri, Abazar, Mohammad Golshan, Saeid Janizadeh, Artemi Cerdà, and Assefa M. Melesse. "Soil Erosion Susceptibility Mapping in Kozetopraghi Catchment, Iran: A Mixed Approach Using Rainfall Simulator and Data Mining Techniques." Land 9, no. 10 (2020): 368. http://dx.doi.org/10.3390/land9100368.
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Soil erosion determines landforms, soil formation and distribution, soil fertility, and land degradation processes. In arid and semiarid ecosystems, soil erosion is a key process to understand, foresee, and prevent desertification. Addressing soil erosion throughout watersheds scales requires basic information to develop soil erosion control strategies and to reduce land degradation. To assess and remediate the non-sustainable soil erosion rates, restoration programs benefit from the knowledge of the spatial distribution of the soil losses to develop maps of soil erosion. This study presents Support Vector Machine (SVM), Random Forest (RF), and adaptive boosting (AdaBoost) data mining models to map soil erosion susceptibility in Kozetopraghi watershed, Iran. A soil erosion inventory map was prepared from field rainfall simulation experiments on 174 randomly selected points along the Kozetopraghi watershed. In previous studies, this map has been prepared using indirect methods such as the Universal Soil Loss Equation to assess soil erosion. Direct field measurements for mapping soil erosion susceptibility have so far not been carried out in our study site in the past. The soil erosion rate data generated by simulated rainfall in 1 m2 plots at rainfall rate of 40 mmh−1 was used to develop the soil erosion map. Of the available data, 70% and 30% were randomly classified to calibrate and validate the models, respectively. As a result, the RF model with the highest area under the curve (AUC) value in a receiver operating characteristics (ROC) curve (0.91), and the lowest mean square error (MSE) value (0.09), has the most concordance and spatial differentiation. Sensitivity analysis by Jackknife and IncNodePurity methods indicates that the slope angle is the most important factor within the soil erosion susceptibility map. The RF susceptibility map showed that the areas located in the center and near the watershed outlet have the most susceptibility to soil erosion. This information can be used to support the development of sustainable restoration plans with more accuracy. Our methodology has been evaluated and can be also applied in other regions.
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Vilkhivskaya, Olga, and Mark Gilbert. "NUCLEAR DATA V&V ANALYSIS FOR FUSION APPLICATIONS: INTEGRAL BENCHMARKS AND DECAY DATA." EPJ Web of Conferences 247 (2021): 10015. http://dx.doi.org/10.1051/epjconf/202124710015.
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A reliable estimation of the operational parameters is one of the primary concerns in the design of magnetic fusion devices such as ITER and DEMO. Methods of diagnostics and control over the critical plasma parameters determining its stability and efficiency rely on the high-energy neutron field monitoring. Extreme operational environment, such as high-energy neutron flux, electromagnetic radiation, and high temperatures might reduce the performance of the detector systems. Therefore, research and development activities in detector prototyping are carried out to address this problem. To predict the performance of the detector materials, simulations using the latest releases of the nuclear data libraries as input for the inventory codes are carried out. This paper describes the latest validation and verification (V&V) benchmark exercise for FISPACT-II & TENDL-2017 based on the fusion decay heat measurements performed at the Japanese FNS facility for the materials in the diagnostic components for the radiation measurements. The breakdown of decay-heat contributions from individual radionuclides have been employed to interpret the simulated results, benchmark the data against the experimental measurements, and revise the neutron-induced reactions cross-section and decay data for the associated radionuclides for the upcoming release of the TENDL-2019 nuclear data library.
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Sobotka, Anna. "Inventory Control: A Simulation and Decision Support System." SIMULATION 71, no. 3 (1998): 141–53. http://dx.doi.org/10.1177/003754979807100301.
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Kilic, Gozde Hilal, Melis Gizem Ozturk, and Ahmet Murat Koseoglu. "Inventory control methods in industry 4.0 implementations." Pressacademia 5, no. 4 (2018): 324–40. http://dx.doi.org/10.17261/pressacademia.2018.991.
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Jackson, Ilya. "Simulation-Optimisation Approach to Stochastic Inventory Control with Perishability." Information Technology and Management Science 22 (December 23, 2019): 9–14. http://dx.doi.org/10.7250/itms-2019-0002.
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In order to tailor inventory control to urgent needs of grocery retail, the discrete-event simulation model with realistic perishability mechanics is proposed in the paper. The model is stochastic and operates with multiple products under constrained total inventory capacity. Besides, the model under consideration is distinguished by quantity discount, uncertain replenishment lags and lost sales. The paper presents both mathematical description and algorithmic implementation. An optimisation framework based on a genetic algorithm is also proposed for deriving an optimal control policy. The proposed approach contributes to the field of industrial engineering by providing a simple and flexible way to compute nearly-optimal inventory control parameters.
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Xing, Jia, Siwei Li, Dian Ding, et al. "Data Assimilation of Ambient Concentrations of Multiple Air Pollutants Using an Emission-Concentration Response Modeling Framework." Atmosphere 11, no. 12 (2020): 1289. http://dx.doi.org/10.3390/atmos11121289.
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Data assimilation for multiple air pollutant concentrations has become an important need for modeling air quality attainment, human exposure, and related health impacts, especially in China, which experiences both PM2.5 and O3 pollution. Traditional data assimilation or fusion methods are mainly focused on individual pollutants and thus cannot support simultaneous assimilation for both PM2.5 and O3. To fill the gap, this study proposed a novel multipollutant assimilation method by using an emission-concentration response model (noted as RSM-assimilation). The new method was successfully applied to assimilate precursors for PM2.5 and O3 in the 28 cities of the North China Plain (NCP). By adjusting emissions of five pollutants (i.e., NOx, sulfur dioxide = SO2, ammonia = NH3, VOC, and primary PM2.5) in the 28 cities through RSM-assimilation, the RMSEs (root mean square errors) of O3 and PM2.5 were reduced by about 35% and 58% from the original simulations. The RSM-assimilation results in small sensitivity to the number of observation sites due to the use of prior knowledge of the spatial distribution of emissions; however, the ability to assimilate concentrations at the edge of the control region is limited. The emission ratios of five pollutants were simultaneously adjusted during the RSM-assimilation, indicating that the emission inventory may underestimate NO2 in January, April, and October, and SO2 in April, but overestimate NH3 in April, and VOC in January and October. Primary PM2.5 emissions were also significantly underestimated, particularly in April (dust season in NCP). Future work should focus on expanding the control area and including NH3 observations to improve the RSM-assimilation performance and emission inventories.
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Wang, Yun Rui. "Enterprise Inventory Management and Simulation." Advanced Materials Research 933 (May 2014): 874–78. http://dx.doi.org/10.4028/www.scientific.net/amr.933.874.
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Inventory is an important link in supply chain, according to characteristics and objectives of inventory control, the reasonable safety inventory, order point, the highest inventory and inventory strategy were determined based on historical sales data. Using Witness simulation software, the optimal strategy was selected from nine inventory strategies by running simulation model for one year. If goods shortage was allowing, the seventh schemes (72000,158100) was better ,the minimum total cost was 888158 yuan ; considering allowing a small amount of shortage, the cost of eighth schemes ( 82000,158100) was least of 1095167; the third scenarios (92000,138100) was selected if without shortage, and the minimum total cost was 1254909 yuan. This shows, the application of computer simulation to assist in the management of inventory is scientific and feasible, it can help enterprises to save the order and operation cost.
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Badri, Masood A. "A Simulation Model for Multi-Product Inventory Control Management." SIMULATION 72, no. 1 (1999): 20–32. http://dx.doi.org/10.1177/003754979907200103.
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Alstrøm, Poul, and Per Madsen. "Tracking signals in inventory control systems A simulation study." International Journal of Production Economics 45, no. 1-3 (1996): 293–302. http://dx.doi.org/10.1016/0925-5273(95)00120-4.
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Gelders, L. F. "Inventory control and management." European Journal of Operational Research 62, no. 3 (1992): 386–87. http://dx.doi.org/10.1016/0377-2217(92)90136-w.
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Qin, Chong, and San Yuan Zhou. "Research on Inventory Control of Colliery Material." Advanced Materials Research 524-527 (May 2012): 2920–25. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.2920.
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System dynamics model of colliery material inventory control, containing chief storage and mine supermarket, was created in this paper. Controllable variables in the model includes chief storage’s inventory, mine supermarket’s expect inventory and mine supermarket’s receive delay time. After adjusting and coordinating them, outcome of simulation, analysis and comparison of the effect variables bring to the colliery material inventory control, value range and best point of the variables will be available, and the optimized scheme contains fulfilling producing material demand, reducing chief storage’s inventory and total inventory of material, decrease colliery material inventory cost will be feasible.
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Douraid, Abdessamad, Hamid Ech-Cheikh, Khalid El Had, and Mohamed Laradi. "Comparing continuous control policies by modeling and simulation of the procurement process." International Journal of Engineering & Technology 9, no. 1 (2020): 211. http://dx.doi.org/10.14419/ijet.v9i1.29949.
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Inventory management is a challenging problem area in supply chain management and companies need to have inventories in warehouses in order to satisfy customer's needs. Meanwhile, these inventories have holding costs and this is a frozen fund that can be lost. Therefore, the task of inventory management is to find the right quantity of inventories that will fulfill the demand with the right price, avoiding overstocks. The aim of this paper is to carry out a comparing study of continuous inventory control policies in a stochastic environment of demand and lead time, in order to find out the impacts of the decision variables of each inventory control policy. For this purpose, the discrete event simulation approach has been chosen to generate various scenarios of inventory control policies of the procurement process by taking into account the production planning of the manufacturing company. The comparison of these configurations based on the essential key performance indicators of the supply chain, namely the cost and service level.
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Bao, Yun, Jun Liu, Min-shu Ma, and Ling-yun Meng. "Seat inventory control methods for Chinese passenger railways." Journal of Central South University 21, no. 4 (2014): 1672–82. http://dx.doi.org/10.1007/s11771-014-2109-y.
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