scholarly journals Pricing and inventory control decisions in the stochastic hybrid production systems with multiple recovery options

Author(s):  
Maryam Esmaeili ◽  
F. Naseri ◽  
M. Seifbarghy ◽  
T. Heydari

Although pricing and inventory control are crucial decisions in each production system, these decisions investigate separately. This paper considers pricing and inventory control decisions simultaneously as a hybrid production system. The hybrid production system with two recovery options, remanufacturing and refurbishing are presented. The demand follows Poisson distribution, which depends on the sale price of each product. Returned products arrive according to a Poisson process. Each returned product can be remanufactured, refurbished, or disposed of. The time to manufacturing, refurbishing, and remanufacturing a product also follows an exponential distribution. By modeling the system as a Markov chain, the long-run expected profit function is derived as a function of the dispose –down-to level of returned products and the order-up-to level and the sale price of serviceable products 1 and 2. Considering pricing and inventory control decisions simultaneously with remanufacturing and refurbishing returned products creates a three-dimensional state space of the Markov Chain with dependence, the sale price of products. Due to the complexity of the model (mixed integer nonlinear programming), the Artificial Bee Colony(ABC)algorithm and complete search method are used. The results show that by increasing the purchase price of returned products, the amount of returned products will increase. If the refurbishing cost of the return products is high or the disposal cost is low, less inventory should be kept in the system with a high price of serviceable products. If the lost sale cost is high, the more inventory should be maintained. Moreover, by decreasing the price elasticity of demand, the customer’s demand is increased, and then more inventory should be kept in the system.

2010 ◽  
Vol 156-157 ◽  
pp. 1497-1500 ◽  
Author(s):  
Meng Qi Li ◽  
Dong Ying Li

In order to reduce the work of repeated nad iterative of process model for manufacturing system, the paper proposed the establishment of three-dimensional "product - process - property" of the modeling methods with matrix mapping technology and mapped products, function, performance, process to model of production system according to the steps. Production system modeling of light-box as a case to detail description of production systems and process modeling. The modeling method with convenience, comprehensive, integrated, inheritable, and sometimes with large amount of calculation.


Author(s):  
SMR Rahman ◽  
MN Islam ◽  
MH Rashid ◽  
NR Sarker ◽  
MSR Siddiki ◽  
...  

An attempt was made to study the existing production and management system under intensive buffalo farming at Dinajpur district, a drought area of Bangladesh. Thirty two farmers were selected for this study. Direct interview with farmers, farm observation, community discussions and key informant interview (KII) were carried out to achieve the study. Two types of intensive system were found, namely – household yard (HYI) and completely intensive (CI). It was observed that in HYI system during the day time the animals were kept in yard and in confinement at night. On the contrary, animals were always remained in the shed under CI system. Feeding practice and utilization of feed resources were found different in HYI and CI farming. Showering of dairy buffaloes was observed as common practices in both production systems. All productive e.g. milk yield, lactation yield, lactation length and dry period and reproductive traits e.g. service per conception, age at first pregnancy, age at first calving and post/partum heat period under CI production system were found significantly (p≤0.05) better than that of the HYI systems. Significantly (p≤0.05) higher total solids and fat were found in milk from CI system compared to the HYI system, but in case of protein it was opposite. Natural breeding showed as more prominent practice than that of the artificial insemination in both farming systems. All the farmers practiced colostrum feeding and the calf mortality ranges from 7-8%. Regarding the primary health care, CI farmers were found to be more attentive than the HYI farmers. Most of the buffaloes showed heat from early night to early morning (78.7%). Problem matrix revealed that the top ranked order of problems were “inadequate knowledge”, “high price of feed” and “low milk price”. However, both systems were found as a profitable venture (benefit cost ratio1.33 in HYI and 1.25 in CI). Bangladesh J. of Livestock Res. 21-25: 103-117, 2018


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Addisu Bihonegn ◽  
Desalegn Begna

The study was conducted in Tehulederie, Kalu, and Dessie Zuria districts of South Wollo Zone, Amhara, Ethiopia, to assess the current beekeeping production system with available opportunities and challenges facing the beekeeping subsector. The districts were purposively selected based on potential and accessibility and then stratified into lowland, midland, and highland. In total, 135 beekeepers, of which 126 were males and 9 were females, were interviewed using a pretested semistructured questionnaire. The result revealed that beekeeping is actively practiced by the community regardless of age and sex. Three beekeeping production systems, that is, traditional, transitional, and movable frame hive, have been identified, accounting for 80%, 4%, and 16%, respectively. More than 80% of total bee colonies are managed being placed in the backyard. Besides, the study indicated that about 79% of the beekeepers keep bees primarily for income generation and home consumption. According to this study, the average bee colony holding size is 5.13 per a beekeeper. Also, this study identified that the swarm catching method is the major source of bee colony accounting for more than 45% to start beekeeping and 76% to increase existing colony number. Bee colony decline, absconding and swarming, honeybee pests and predators, and lack of training and extension were identified as major beekeeping challenges in the study areas. This study identified the beekeeping production system, opportunities, and challenges of the study areas and has significantly contributed to our knowledge and identified lack of extension and training as intervention areas. Therefore, practical beekeeping training and extension should get primary emphasis to combat the existing challenges.


Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 729
Author(s):  
Mario Šporčić ◽  
Marijan Šušnjar ◽  
Zdravko Pandur ◽  
Marin Bačić ◽  
David Mijoč ◽  
...  

Skidders, as self-propelled machines designed to transport trees or parts of trees by trailing or dragging it from the woods to a landing area, are still extensively used as the main wood extraction equipment in most of the Europe and worldwide. The high price of new machines (and even higher for CTL technology) makes the second-hand skidder market very interesting and appealing, especially for small forest owners and forestry contractors. So, this paper reports on a survey of used skidders available for purchase on the European market. Up-to-date empirical data was gathered by the analysis of the offerings on the main online marketplaces, i.e., specialized websites. The study included skidder make and model, variation in their age, annual usage and resale prices. The survey identified a total of 163 second-hand skidders and the results pointed out the prevalence of small-size machines (<110 kW), the average annual use (after excluding 1 year old machines from calculation) of 863 hours per year and the average re-sale price of about 65,000 EUR. Skidders are most commonly re-sold at an age of 16 years and the calculated price models show that skidder age is a stronger predictor of their value, i.e., resale price, than the total machine working hours. In the concluding section, paper also includes some reflections on possible future trends and perspectives of skidding technology in forestry.


2021 ◽  
Vol 12 (1) ◽  
pp. 157-172
Author(s):  
Shankar G. Shanmugam ◽  
Normie W. Buehring ◽  
Jon D. Prevost ◽  
William L. Kingery

Our understanding on the effects of tillage intensity on the soil microbial community structure and composition in crop production systems are limited. This study evaluated the soil microbial community composition and diversity under different tillage management systems in an effort to identify management practices that effectively support sustainable agriculture. We report results from a three-year study to determine the effects on changes in soil microbial diversity and composition from four tillage intensity treatments and two residue management treatments in a corn-soybean production system using Illumina high-throughput sequencing of 16S rRNA genes. Soil samples were collected from tillage treatments at locations in the Southern Coastal Plain (Verona, Mississippi, USA) and Southern Mississippi River Alluvium (Stoneville, Mississippi, USA) for soil analysis and bacterial community characterization. Our results indicated that different tillage intensity treatments differentially changed the relative abundances of bacterial phyla. The Mantel test of correlations indicated that differences among bacterial community composition were significantly influenced by tillage regime (rM = 0.39, p ≤ 0.0001). Simpson’s reciprocal diversity index indicated greater bacterial diversity with reduction in tillage intensity for each year and study location. For both study sites, differences in tillage intensity had significant influence on the abundance of Proteobacteria. The shift in the soil bacterial community composition under different tillage systems was strongly correlated to changes in labile carbon pool in the system and how it affected the microbial metabolism. This study indicates that soil management through tillage intensity regime had a profound influence on diversity and composition of soil bacterial communities in a corn-soybean production system.


2014 ◽  
Vol 1036 ◽  
pp. 864-868 ◽  
Author(s):  
Marcin Zemczak ◽  
Damian Krenczyk

The paper presents the task scheduling issue, which main aim is to establish a proper sequence of tasks, that would maximize the utilization of companys production capacity. According to the literature sources, the presented sequencing problem, denoted as CSP (Car Sequencing Problem) belongs to the NP-hard class, as has been proven by simple reduction from Hamiltonians Path problem. Optimal method of solution has not yet been found, only approximate solutions have been offered, especially from the range of evolutionary algorithms. Regardless of specific production system, while considering reception of new tasks into the system, current review of the state of the system is required in order to decide whether and when a new order can be accepted for execution. In this paper, the problem of task scheduling is limited to the specific existing mixed-model production system. The main goal is to determine the effective method of creation of task sequence. Through the use of computational algorithms, and automatic analysis of the resulting sequence, rates of production are able to be checked in a real time, and so improvements can be proposed and implemented.


2015 ◽  
Vol 6 (4) ◽  
pp. 60-69 ◽  
Author(s):  
Sławomir Kłos ◽  
Peter Trebuna

Abstract This paper proposes the application of computer simulation methods to support decision making regarding intermediate buffer allocations in a series-parallel production line. The simulation model of the production system is based on a real example of a manufacturing company working in the automotive industry. Simulation experiments were conducted for different allocations of buffer capacities and different numbers of employees. The production system consists of three technological operations with intermediate buffers between each operation. The technological operations are carried out using machines and every machine can be operated by one worker. Multi-work in the production system is available (one operator operates several machines). On the basis of the simulation experiments, the relationship between system throughput, buffer allocation and the number of employees is analyzed. Increasing the buffer capacity results in an increase in the average product lifespan. Therefore, in the article a new index is proposed that includes the throughput of the manufacturing system and product life span. Simulation experiments were performed for different configurations of technological operations.


2009 ◽  
Vol 62-64 ◽  
pp. 275-292
Author(s):  
R.H. Weston

With increased product dynamics world-wide, the average economic lifetime of production systems is falling. Industrial robots are widely assumed to be inherently flexible and therefore that they can function as a programmable building block of response production systems. This paper reviews common capabilities of contemporary industrial robotic systems and investigates their capability to extend the useful lifetime of production system by coping with different types of product dynamic. Also considered are relative capabilities of conventional programmable robots and an emerging generation of programmable and configurable component-based machines.


2021 ◽  
Author(s):  
Daiki Kato ◽  
Kenya Yoshitugu ◽  
Naoki Maeda ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  

Abstract Most industrial robots are taught using the teaching playback method; therefore, they are unsuitable for use in variable production systems. Although offline teaching methods have been developed, they have not been practiced because of the low accuracy of the position and posture of the end-effector. Therefore, many studies have attempted to calibrate the position and posture but have not reached a practical level, as such methods consider the joint angle when the robot is stationary rather than the features during robot motion. Currently, it is easy to obtain servo information under numerical control operations owing to the Internet of Things technologies. In this study, we propose a method for obtaining servo information during robot motion and converting it into images to find features using a convolutional neural network (CNN). Herein, a large industrial robot was used. The three-dimensional coordinates of the end-effector were obtained using a laser tracker. The positioning error of the robot was accurately learned by the CNN. We extracted the features of the points where the positioning error was extremely large. By extracting the features of the X-axis positioning error using the CNN, the joint 1 current is a feature. This indicates that the vibration current in joint 1 is a factor in the X-axis positioning error.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jagan Mohan Reddy K. ◽  
Neelakanteswara Rao A. ◽  
Krishnanand Lanka ◽  
PRC Gopal

Purpose Pull production systems have received much attention in the supply chain management environment. The number of Kanbans is a key decision variable in the pull production system as it affects the finished goods inventory (FGI) and backorders of the system. The purpose of this study is to compare the performance of the fixed and dynamic Kanban systems in terms of operational metrics (FGI and backorders) under the demand uncertainty. Design/methodology/approach In this paper, the system dynamics (SD) approach was used to model the performance of fixed and dynamic Kanban based production systems. SD approach has enabled the feedback mechanism and is an appropriate tool to incorporate the dynamic control during the simulation. Initially, a simple Kanban based production system was developed and then compared the performance of production systems with fixed and dynamic controlled Kanbans at the various demand scenarios. Findings From the present study, it is observed that the dynamic Kanban system has advantages over the fixed Kanban system and also observed that the variation in the backorders with respect to the demand uncertainty under the dynamic Kanban system is negligible. Research limitations/implications In a just-in-time production system, the number of Kanbans is a key decision variable. The number of Kanbans is mainly depended on the demand, cycle time, safety stock factor (SSF) and container size. However, this study considered only demand uncertainty to compare the fixed and dynamic Kanban systems. This paper further recommends researchers to consider other control variables which may influence the number of Kanbans such as cycle time, SSF and container size. Originality/value This study will be useful to decision-makers and production managers in the selection of the Kanban systems in uncertain demand applications.


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