Статті в журналах: "Minimizing total deviation"

1

Mosheiov, Gur. "Minimizing total completion time and total deviation of job completion times from a restrictive due-date." European Journal of Operational Research 165, no. 1 (August 2005): 20–33. http://dx.doi.org/10.1016/j.ejor.2003.09.029.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Choi, Byung-Cheon, Yunhong Min, and Myoung-Ju Park. "Strong NP-hardness of minimizing total deviation with generalized and periodic due dates." Operations Research Letters 47, no. 5 (September 2019): 433–37. http://dx.doi.org/10.1016/j.orl.2019.08.002.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Chang, Pei‐Chann (Michael), and Han‐Chau (Garey) Lee. "A two‐phase approach for single machine scheduling problems: Minimizing the total absolute deviation." Journal of the Chinese Institute of Engineers 15, no. 6 (September 1992): 735–42. http://dx.doi.org/10.1080/02533839.1992.9677469.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Gao, Yuan, and Jinjiang Yuan. "Unary NP-hardness of minimizing the total deviation with generalized or assignable due dates." Discrete Applied Mathematics 189 (July 2015): 49–52. http://dx.doi.org/10.1016/j.dam.2015.03.011.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Chang, Pei-Chann, Jih-Chang Hsieh, and Yen-Wen Wang. "Genetic algorithms applied in BOPP film scheduling problems: minimizing total absolute deviation and setup times." Applied Soft Computing 3, no. 2 (September 2003): 139–48. http://dx.doi.org/10.1016/s1568-4946(03)00009-7.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Su, Ling-Huey, Fuh-Der Chou, and James C. Chen. "Minimizing makespan subject to minimum total absolute deviation of completion time on identical parallel machines." Engineering Optimization 44, no. 10 (October 2012): 1187–95. http://dx.doi.org/10.1080/0305215x.2011.644544.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Su, Ling-Huey, and Hui-Mei Wang. "Minimizing total absolute deviation of job completion times on a single machine with cleaning activities." Computers & Industrial Engineering 103 (January 2017): 242–49. http://dx.doi.org/10.1016/j.cie.2016.11.009.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Liu, Shuo, Weizhen Zhu, Zhaopeng Xu, and Meijing Gao. "Automatic and robust phase aberration compensation for digital holographic microscopy based on minimizing total standard deviation." Optics and Lasers in Engineering 134 (November 2020): 106276. http://dx.doi.org/10.1016/j.optlaseng.2020.106276.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Shahrokhi, Saman, Adel El-Shahat, Fatemeh Masoudinia, Foad H. Gandoman, and Shady H. E. Abdel Aleem. "Sizing and Energy Management of Parking Lots of Electric Vehicles Based on Battery Storage with Wind Resources in Distribution Network." Energies 14, no. 20 (October 17, 2021): 6755. http://dx.doi.org/10.3390/en14206755.

Повний текст джерела

Анотація:

In this paper, an optimal sizing and placement framework (OSPF) is performed for electric parking lots integrated with wind turbines in a 33-bus distribution network. The total objective function is defined as minimizing the total cost including the cost of grid power, cost of power losses, cost of charge and discharge of parking lots, cost of wind turbines as well as voltage deviations reduction. In the OSPF, optimization variables are selected as electric parking size and wind turbines, which have been determined optimally using an intelligent method named arithmetic optimization algorithm (AOA) inspired by arithmetic operators in mathematics. The load following strategy (LFS) is used for energy management in the OSPF. The OSPF is evaluated in three cases of the objective function such as minimizing the cost of power losses, minimizing the network voltage deviations, and minimizing the total objective function using the AOA. The capability of the AOA is compared with the well-known particle swarm optimization (PSO) and artificial bee colony (ABC) algorithms for solving the OSPF in the last case. The findings show that the power loss, voltage deviations, and power purchased from the grid are reduced considerably based on the OSPF using the AOA. The results show the lowest total cost of energy and also minimum network voltage deviation (third case) by the AOA in comparison with the PSO and ABC with a higher convergence rate, which confirms the better capability of the proposed method. The results of the first and second cases show the high cost of power purchased from the main grid as well as the high total cost. Therefore, the comparison of different cases confirms that considering the cost index along with losses and voltage deviations causes a compromise between different objectives, and thus the cost of purchasing power from the main network is significantly reduced. Moreover, the voltage profile of the network improves, and also the minimum voltage of the network is also enhanced using the OSPF via the AOA.

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Ganesan, Viswanath Kumar, and Appa Iyer Sivakumar. "Scheduling in static jobshops for minimizing mean flowtime subject to minimum total deviation of job completion times." International Journal of Production Economics 103, no. 2 (October 2006): 633–47. http://dx.doi.org/10.1016/j.ijpe.2005.12.004.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Khadka, Shree Ram. "Improved Upper Bound to Product Rate Variation Problem." Nepali Mathematical Sciences Report 37, no. 1-2 (December 31, 2020): 47–54. http://dx.doi.org/10.3126/nmsr.v37i1-2.34069.

Повний текст джерела

Анотація:

The sequencing problem which minimizes the deviation between the actual (integral) and the ideal (rational) cumulative production of a variety of models of a common base product is called the product rate variation problem. If the objective is to minimize the maximum deviation, the problem is bottleneck product rate variation problem and the problem with the objective of minimizing all the deviations is the total product rate variation problem. The problem has been widely studied with several pseudo-polynomial time exact algorithms and heurism-tics. The lower bound of a feasible solution to the problem has been investigated to be tight. However, the upper bound of a feasible solution had been established in the literature which could further be improved. In this paper, we propose the improved upper bound for BPRVP and TPRVP.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Khadka, Shree Ram. "Improved Upper Bound to Product Rate Variation Problem." Nepali Mathematical Sciences Report 37, no. 1-2 (December 31, 2020): 47–54. http://dx.doi.org/10.3126/nmsr.v37i1-2.34069.

Повний текст джерела

Анотація:

The sequencing problem which minimizes the deviation between the actual (integral) and the ideal (rational) cumulative production of a variety of models of a common base product is called the product rate variation problem. If the objective is to minimize the maximum deviation, the problem is bottleneck product rate variation problem and the problem with the objective of minimizing all the deviations is the total product rate variation problem. The problem has been widely studied with several pseudo-polynomial time exact algorithms and heurism-tics. The lower bound of a feasible solution to the problem has been investigated to be tight. However, the upper bound of a feasible solution had been established in the literature which could further be improved. In this paper, we propose the improved upper bound for BPRVP and TPRVP.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Tighazoui, Ayoub, Christophe Sauvey, and Nathalie Sauer. "Minimizing the Total Weighted Waiting Times and Instability in a Rescheduling Problem with Dynamic Jobs Weight." Applied Sciences 11, no. 15 (July 30, 2021): 7040. http://dx.doi.org/10.3390/app11157040.

Повний текст джерела

Анотація:

Thanks to smart technological tools, customers can at any moment create or modify their commands. This reality forced many production firms to become sensitive in rescheduling processes. In the literature, most of rescheduling problems consider classical efficiency measures. However, some existing works also consider stability as a measure for limiting the deviation from initial schedule. In this work, we aim to bridge the gap in existing works on rescheduling by investigating a new approach to measure simultaneously efficiency by the total weighted waiting times and stability by the total weighted completion time deviation. This combination of criteria is very significant in industrial and hospital environments. In this paper, a single machine rescheduling problem with jobs arriving over time is considered. A mixed integer linear programming (MILP) model is designed for this problem and an iterative predictive-reactive strategy for dealing with the online part. Numerical results show that, at each time the jobs are rescheduled, the low weight ones move forward. Consequently, a new concept consisting in increasing the jobs weight as function of time is established. The effect of this new conception is evaluated by the variation of the average flowtime. Eventually, the computing time of the MILP resolution is studied to explore its limitations.

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Mosheiov, G. "Minimizing total absolute deviation of job completion times: extensions to position-dependent processing times and parallel identical machines." Journal of the Operational Research Society 59, no. 10 (October 2008): 1422–24. http://dx.doi.org/10.1057/palgrave.jors.2602480.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Javed, Shazia, and Noor Atinah Ahmad. "A Stochastic Total Least Squares Solution of Adaptive Filtering Problem." Scientific World Journal 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/625280.

Повний текст джерела

Анотація:

An efficient and computationally linear algorithm is derived for total least squares solution of adaptive filtering problem, when both input and output signals are contaminated by noise. The proposed total least mean squares (TLMS) algorithm is designed by recursively computing an optimal solution of adaptive TLS problem by minimizing instantaneous value of weighted cost function. Convergence analysis of the algorithm is given to show the global convergence of the proposed algorithm, provided that the stepsize parameter is appropriately chosen. The TLMS algorithm is computationally simpler than the other TLS algorithms and demonstrates a better performance as compared with the least mean square (LMS) and normalized least mean square (NLMS) algorithms. It provides minimum mean square deviation by exhibiting better convergence in misalignment for unknown system identification under noisy inputs.

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Antonioli, Massimo Pinto, Carlos Diego Rodrigues, and Bruno de Athayde Prata. "Minimizing total tardiness for the order scheduling problem with sequence-dependent setup times using hybrid matheuristics." International Journal of Industrial Engineering Computations 13, no. 2 (2022): 223–36. http://dx.doi.org/10.5267/j.ijiec.2021.11.002.

Повний текст джерела

Анотація:

This paper aims at presenting a customer order scheduling environment in which the setup times are explicit and depend on the production sequence. The considered objective function is the total tardiness minimization. Since the variant under study is NP-hard, we propose a mixed-integer linear programming (MILP) model, an adaptation of the Order-Scheduling Modified Due-Date heuristic (OMDD) (referred to as Order-Scheduling Modified Due-Date Setup (OMMD-S)), an adaptation of the Framinan and Perez-Gonzalez heuristic (FP) (hereinafter referred to as Framinan and Perez-Gonzalez Setup (FP-S)), a matheuristic with Same Permutation in All Machines (SPAM), and the hybrid matheuristic SPAM-SJPO based on Job-Position Oscillation (JPO). The algorithms under comparison have been compared on an extensive benchmark of randomly generated test instances, considering two performance measures: Relative Deviation Index (RDI) and Success Rate (SR). For the small-size evaluated instances, the SPAM is the most efficient algorithm, presenting the better values of RDI and SR. For the large-size evaluated instances, the hybrid matheuristic SPAM-JPO and MILP model are the most efficient methods.

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Brabie, D., and E. Andersson. "On minimizing derailment risks and consequences for passenger trains at higher speeds." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 223, no. 6 (June 17, 2009): 543–66. http://dx.doi.org/10.1243/09544097jrrt271.

Повний текст джерела

Анотація:

The first part of this article deals with the possibility of preventing wheel climbing derailments after an axle journal failure by implementing mechanical restrictions between the wheelsets and the bogie. A multi-body system (MBS) computer model is developed to account for such an axle failure condition, which is successfully validated by comparing the pre-derailment sequence of events with two authentic cases. An extensive parameter analysis on the maximum vertical and longitudinal play between the wheelset and the bogie, required to prevent a high-speed power or trailer car to derail, is performed for various combinations of running conditions in curves. Once an actual derailment has occurred on conventional passenger trains at 200 km/h, extensive MBS simulations are performed on the feasibility of utilizing alternative substitute guidance mechanisms, such as low-reaching parts of bogie frame, axle box, or brake disc, as means of minimizing the lateral deviation. Results are presented in terms of geometrical parameters that lead to a successful engagement with the rail for a total of 12 different derailment scenarios. These are caused by an axle journal failure, an impact with a small object on the track, or a high rail failure. Minimizing the lateral deviation is also investigated by means of restraining the maximum coupler yaw angle and altering the bogie yaw stiffness. Time-domain simulations are also performed in terms of lateral track forces and derailment ratio when negotiating a tight horizontal ‘ S-curve’. Further, the articulated train concept is investigated in terms of the post-derailment vehicle behaviour after derailments on tangent and curved track at a speed of 200 km/h. In this respect, a trainset consisting of one power car and four articulated passenger trailer cars is modelled in the MBS software. Results in terms of lateral deviation and maximum carbody roll angle are presented as a function of different inter-carbody damper characteristics and running gear features. The feasibility of these damper characteristics is also tested in terms of lateral track forces and derailment ratio when negotiating a tight horizontal S-curve.

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Chen, Chung Ho. "Economic Design of a Combined Continuous Lot by Lot Acceptance Sampling Plan under the Quality Investment." Applied Mechanics and Materials 145 (December 2011): 410–14. http://dx.doi.org/10.4028/www.scientific.net/amm.145.410.

Повний текст джерела

Анотація:

In this study, the economic selection of quality investment for designing a combined continuous lot by lot acceptance sampling plan with average outgoing quality limit (AOQL) protection is proposed. Both the mean and the standard deviation of the process are measured as an exponential function of the quality investment. The optimal combination of parameters for single and continuous sampling plan and the quality investment level is jointly determined by minimizing the expected total cost of product under the specified AOQL value.

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Demirci, Mehmet, Ahmet Yesil, and Pete Bettinger. "Introducing a New Approach in Stand Tending Planning and Thinning Block Designation by Using Mixed Integer Goal Programming." Croatian journal of forest engineering 43, no. 1 (November 24, 2021): 137–54. http://dx.doi.org/10.5552/crojfe.2022.1093.

Повний текст джерела

Анотація:

Long-term management plans have been developed for nearly all of the forests in Turkey. These plans are applied at a sub-district management unit level and may contain guidance for both intermediate yield and final yield harvests. To implement an intermediate yield plan, which involves the scheduling of forest thinnings (stand tending), consideration in Turkey is given to the advantages of working in the same terrain and the same general area each year. Therefore, compartments are often clumped together to create thinning blocks, taking into consideration the thinning priority of the stands, road conditions, site index, age, and proximity of the compartments. Further, when preparing annual budgets and planning to meet the market’s needs, forest enterprises require an even flow of intermediate wood volume each year. In this paper, we introduce a new approach in stand tending planning designed to schedule an equal amount of intermediate wood volume each year and to create thinning blocks by minimizing the distance to pre-defined ramps (landings). We developed both linear and nonlinear goal programming models to minimize both the deviations from a harvest volume (annual intermediate yield allowable cut) target and the deviations from a target value determined for the distances (total and average) of the centroid of each compartment to the hypothetical forest ramps. By using the extended version of Lingo 16, we solved the problem with different weights for the deviations in volume and distance that ranged from 0.0 to 1.0, in 10% intervals, which created 11 scenarios. We carefully analyzed the results of each scenario by taking into consideration the wood volume and distance of compartments to the ramps. The best scenario using the linear model produced a deviation in volume scheduled for the entire decade of 6 m3, while the deviation in total distance between harvest areas and ramps was 59.7 km. Scenario 5, with weights of 0.6 for volume and 0.4 for distance, produced these results, where compartments were closest to one another. The best scenario using the nonlinear model also produced a deviation in volume of 0 m3 and the total average deviation in distance between harvest areas and ramps was 8.7 km. Scenario 3, with weights of 0.8 for volume and 0.2 for distance, produced these results. The approach and models described through this study may be appropriate for further integration into forest management planning processes developed for the planning of Mediterranean forests.

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Mor, Baruch, and Gur Mosheiov. "A note: minimizing total absolute deviation of job completion times on unrelated machines with general position-dependent processing times and job-rejection." Annals of Operations Research 271, no. 2 (February 2, 2018): 1079–85. http://dx.doi.org/10.1007/s10479-018-2779-1.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Raza, Muhammad Aamir, and Wang Liang. "Robust Design Optimization of an Aerospace Vehicle Prolusion System." Mathematical Problems in Engineering 2011 (2011): 1–18. http://dx.doi.org/10.1155/2011/145692.

Повний текст джерела

Анотація:

This paper proposes a robust design optimization methodology under design uncertainties of an aerospace vehicle propulsion system. The approach consists of 3D geometric design coupled with complex internal ballistics, hybrid optimization, worst-case deviation, and efficient statistical approach. The uncertainties are propagated through worst-case deviation using first-order orthogonal design matrices. The robustness assessment is measured using the framework of mean-variance and percentile difference approach. A parametric sensitivity analysis is carried out to analyze the effects of design variables variation on performance parameters. A hybrid simulated annealing and pattern search approach is used as an optimizer. The results show the objective function of optimizing the mean performance and minimizing the variation of performance parameters in terms of thrust ratio and total impulse could be achieved while adhering to the system constraints.

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Belbachir, Nasreddine, Mohamed Zellagui, Adel Lasmari, Claude Ziad El-Bayeh, and Benaissa Bekkouche. "Optimal integration of photovoltaic distributed generation in electrical distribution network using hybrid modified PSO algorithms." Indonesian Journal of Electrical Engineering and Computer Science 24, no. 1 (October 1, 2021): 50. http://dx.doi.org/10.11591/ijeecs.v24.i1.pp50-60.

Повний текст джерела

Анотація:

The satisfaction of electricity customers and environmental constraints imposed have made the trend towards renewable energies making them more essential due to their advantages as reducing power losses and ameliorating system’s voltage profiles and reliability. This article addresses the optimal location and size of multiple distributed generations (DGs) based on solar photovoltaic panels (PV) connected to electrical distribution network (EDN) using the various proposed hybrid particle swarm optimization (PSO) algorithms based on chaotic maps and adaptive acceleration coefficients. These algorithms are implemented to optimally allocate the DGs based PV (PV-DG) into EDN by minimizing the multi-objective function (MOF), which is represented as the sum of three technical parameters of the total active power loss (TAPL), total voltage deviation (TVD), and total operation time (TOT) of overcurrent relays (OCRs). The effectiveness of the proposed PSO algorithms were validated on both standards IEEE 33-bus, and 69-bus. The optimal integrating of PV-DGs into EDNs reduced the TAPL percentage by 56.94 % for the IEEE 33-bus and by 61.17 % for the IEEE 69-bus test system, enhanced the voltage profiles while minimizing the TVD by 37.35 % and by 32.27 % for two EDNs, respectively.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Lee, Wen-Chiung, and Jen-Ya Wang. "A three-agent scheduling problem for minimizing the flow time on two machines." RAIRO - Operations Research 54, no. 2 (February 27, 2020): 307–23. http://dx.doi.org/10.1051/ro/2019088.

Повний текст джерела

Анотація:

This study introduces a two-machine three-agent scheduling problem. We aim to minimize the total tardiness of jobs from agent 1 subject to that the maximum completion time of jobs from agent 2 cannot exceed a given limit and that two maintenance activities from agent 3 must be conducted within two maintenance windows. Due to the NP-hardness of this problem, a genetic algorithm (named GA+) is proposed to obtain approximate solutions. On the other hand, a branch-and-bound algorithm (named B&B) is developed to generate the optimal solutions. When the problem size is small, we use B&B to verify the solution quality of GA+. When the number of jobs is large, a relative deviation is proposed to show the gap between GA+ and another ordinary genetic algorithm. Experimental results show that the proposed genetic algorithm can generate approximate solutions by consuming reasonable execution time.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Vaisi, Bahareh, Hiwa Farughi, and Sadigh Raissi. "Schedule-Allocate and Robust Sequencing in Three-Machine Robotic Cell under Breakdowns." Mathematical Problems in Engineering 2020 (October 30, 2020): 1–24. http://dx.doi.org/10.1155/2020/4597827.

Повний текст джерела

Анотація:

The purpose of this paper is to model two problems comprising schedule-allocate (in case of producing identical parts) and sequencing of parts (in case of producing different parts). The first model is used for minimizing the cycle time and operational cost, and the second one for minimizing both the mean and standard deviation of the total production cost as well the cycle time, in an unreliable three-machine robotic cell which confronted with many uncertainty factors. In the current article, mathematical modelling and simulation-based optimization method have been presented to schedule-allocate similar parts and trace the optimal sequence of different parts. Several solution procedures, including epsilon-constraint method and multiobjective particle swarm optimization algorithm, for identical parts case and response surface methodology for different parts case are applied. The results derived from solving numerical examples revealed some advantages in terms of time to attain the optimal solution.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Xu, Wenkai, Peng Zhao, and Liqiao Ning. "A Practical Method for Timetable Rescheduling in Subway Networks during the End-of-Service Period." Journal of Advanced Transportation 2018 (June 27, 2018): 1–9. http://dx.doi.org/10.1155/2018/5914276.

Повний текст джерела

Анотація:

This study proposes a biobjective optimization method for timetable rescheduling during the end-of-service period of a subway network, taking all stakeholders’ interests into consideration. We seek to minimize the total transfer waiting time for all transfer passengers, meanwhile minimizing the deviation to the scheduled timetable. The ε-constraint method and linearization techniques are utilized to obtain the approximate Pareto optimal solutions within limited seconds, allowing for figuring out the trade-off between the two objectives. The method is validated by numerical experiments for different delay scenarios based on a real-world case: the Beijing subway network.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Wang, Xiaoqing, Chun-Hung Chiu, and Wei Guo. "Improving the Performance of Modular Production in the Apparel Assembly: A Mathematical Programming Approach." Mathematical Problems in Engineering 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/472781.

Повний текст джерела

Анотація:

We construct the mathematical models to find the optimal allocation of the module’s capacity (module members) to different assembly operations in a module for given garment assembly tasks in a modular production system. The objectives of the models are minimizing the holding cost for work in process (WIP) inventories in the module and the total deviation of the WIP inventories from their corresponding target values in the module during a specific time interval. The solutions of the models can be used as reference to achieve better allocation of the module members to different operations in a module to fulfill the given garment assembly tasks.

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Suresh, Chintalapudi Venkata, and Sirigiri Sivangaraju. "Multi-objective optimal reactive power dispatch to maximize power system social welfare in the presence of generalized unified power flow controller." Archives of Electrical Engineering 64, no. 3 (September 1, 2015): 405–26. http://dx.doi.org/10.2478/aee-2015-0032.

Повний текст джерела

Анотація:

Abstract In this paper a novel non-linear optimization problem is formulated to maximize the social welfare in restructured environment with generalized unified power flow controller (GUPFC). This paper presents a methodology to optimally allocate the reactive power by minimizing voltage deviation at load buses and total transmission power losses so as to maximize the social welfare. The conventional active power generation cost function is modified by combining costs of reactive power generated by the generators, shunt capacitors and total power losses to it. The formulated objectives are optimized individually and simultaneously as multi-objective optimization problem, while satisfying equality, in-equality, practical and device operational constraints. A new optimization method, based on two stage initialization and random distribution processes is proposed to test the effectiveness of the proposed approach on IEEE-30 bus system, and the detailed analysis is carried out.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Yu, Dong-Yun, and Gui-Ling Wu. "Application of Data Mining Algorithm in Agricultural Products Logistics Network Planning." Security and Communication Networks 2022 (May 4, 2022): 1–9. http://dx.doi.org/10.1155/2022/5884050.

Повний текст джерела

Анотація:

The location of agricultural products center is related to the overall operation efficiency of logistics system and has a great impact on the follow-up agricultural products distribution route planning. The distribution route planning directly determines the total transportation cost and customer service quality of the whole logistics system. In this study, the problem of location path under the background of agricultural products logistics is studied, and an algorithm of agricultural products logistics network planning based on space-time constraints is proposed. An algorithm based on K-means is used to cluster the time-space double factors of customers. Minimize the total distribution cost under the constraints of meeting customer needs and minimizing time window deviation. Experimental results show that the proposed algorithm has better performance through Taguchi analysis and master-slave two-layer model analysis, and its algorithm has better convergence and sensitivity and can better reduce the total cost of distribution and the length of transportation path.

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Wang, Weixin, Jiafu Su, Jin Xu, and Xianlong Ge. "Reactive Strategies in the Multiproject Scheduling with Multifactor Disruptions." Mathematical Problems in Engineering 2020 (May 30, 2020): 1–11. http://dx.doi.org/10.1155/2020/3154047.

Повний текст джерела

Анотація:

Multiproject scheduling aims at the generation of the baseline schedules, which has been studied for several years with the goal of minimizing the total cost of the project. In this paper, we analyzed the impact of network structure disruption, activity disruption, and resource disruption on scheduling scheme, respectively; this problem is related to the disruptions in scheduling process, which leads to a deviation between actual scheduling and baseline scheduling. The mode of the related activities is changed and the start time is reset. Because it is a NP-hard problem and involves a large number of activities, the dual population genetic algorithm is designed to solve this problem. From the results of case analysis, we find that single disruption on scheduling was local, when there was no resource conflict. While multifactor disruptions have greater effect on duration and total cost, multifactor disruptions would affect each other, so it was more complicated.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Kim, Byungjoon B. J., Theodore R. Delbridge, and Dawn B. Kendrick. "Adjusting patients streaming initiated by a wait time threshold in emergency department for minimizing opportunity cost." International Journal of Health Care Quality Assurance 30, no. 6 (August 14, 2017): 516–27. http://dx.doi.org/10.1108/ijhcqa-10-2016-0155.

Повний текст джерела

Анотація:

Purpose Two different systems for streaming patients were considered to improve efficiency measures such as waiting times (WTs) and length of stay (LOS) for a current emergency department (ED). A typical fast track area (FTA) and a fast track with a wait time threshold (FTW) were designed and compared effectiveness measures from the perspective of total opportunity cost of all patients’ WTs in the ED. The paper aims to discuss these issues. Design/methodology/approach This retrospective case study used computerized ED patient arrival to discharge time logs (between July 1, 2009 and June 30, 2010) to build computer simulation models for the FTA and fast track with wait time threshold systems. Various wait time thresholds were applied to stream different acuity-level patients. National average wait time for each acuity level was considered as a threshold to stream patients. Findings The fast track with a wait time threshold (FTW) showed a statistically significant shorter total wait time than the current system or a typical FTA system. The patient streaming management would improve the service quality of the ED as well as patients’ opportunity costs by reducing the total LOS in the ED. Research limitations/implications The results of this study were based on computer simulation models with some assumptions such as no transfer times between processes, an arrival distribution of patients, and no deviation of flow pattern. Practical implications When the streaming of patient flow can be managed based on the wait time before being seen by a physician, it is possible for patients to see a physician within a tolerable wait time, which would result in less crowded in the ED. Originality/value A new streaming scheme of patients’ flow may improve the performance of fast track system.

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Haescher, Marian, Wencke Chodan, Florian Höpfner, Gerald Bieber, Mario Aehnelt, Karthik Srinivasan, and Margit Alt Murphy. "Automated fall risk assessment of elderly using wearable devices." Journal of Rehabilitation and Assistive Technologies Engineering 7 (January 2020): 205566832094620. http://dx.doi.org/10.1177/2055668320946209.

Повний текст джерела

Анотація:

Introduction Falls cause major expenses in the healthcare sector. We investigate the ability of supporting a fall risk assessment by introducing algorithms for automated assessments of standardized fall risk-related tests via wearable devices. Methods In a study, 13 participants conducted the standardized 6-Minutes Walk Test, the Timed-Up-and-Go Test, the 30-Second Sit-to-Stand Test, and the 4-Stage Balance Test repeatedly, producing 226 tests in total. Automated algorithms computed by wearable devices, as well as a visual analysis of the recorded data streams, were compared to the observational results conducted by physiotherapists. Results There was a high congruence between automated assessments and the ground truth for all four test types (ranging from 78.15% to 96.55%), with deviations ranging all well within one standard deviation of the ground truth. Fall risk (assessed by questionnaire) correlated with the individual tests. Conclusions The automated fall risk assessment using wearable devices and algorithms matches the validity of the ground truth, thus providing a resourceful alternative to the effortful observational assessment, while minimizing the risk of human error. No single test can predict overall fall risk; instead, a much more complex model with additional input parameters (e.g., fall history, medication etc.) is needed.

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Hocine, Sekhane, and Labed Djamel. "Optimal number and location of UPFC devices to enhence voltage profile and minimizing losses in electrical power systems." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 5 (October 1, 2019): 3981. http://dx.doi.org/10.11591/ijece.v9i5.pp3981-3992.

Повний текст джерела

Анотація:

The fast increase of loads around the world has made electrical networks more and more complex and difficult to operate close to its capacities. This is has led to many problems such as voltage collapse and energy losses. Therefore, flexible alternating current transmission systems (FACTS) are considred as a best solution for solving these problems. Unified Power Flow Controller UPFC is one of the most important and powerful FACTS devices due to its ability to increase the transmission capacity of the power system and reduce the total line losses. The problem of optimizing its number, location and size has become an important requirement for best advantages of this device. In this paper, a proposed relationship to identify the maximum number of FACTS devices that can be installed for a given power network is introduced in the search process code to determine the optimal number, optimal placement and size of UPFC device to enhance voltages profile and reduce overall system losses in the standard IEEE 14 bus test system using genetic algorithm (GA). The obtained results show clearly that all control parameters of UPFCs in each case are within their limits, and whenever the number of UPFCs installed increases, both voltage deviation and total losses well decreases. They also show that the application of the proposed relationship in the search process code facilitates greatly the search for optimal number, optimal placement and size of UPFC devices and reduces the calculation time. On the other hand, the obtained results has been scientifically justified and compared with other works reported in the literature.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Wang, Yangyang, Guangda Chen, and Yuanxing Jiang. "A novel evaluation method for vehicle and traffic performance of different decision control of automatic lane change based on miniature model." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, no. 12 (May 21, 2020): 2794–806. http://dx.doi.org/10.1177/0954407020919578.

Повний текст джерела

Анотація:

Research on automatic lane-change decision is mainly limited to simulation validation and lacks real vehicle validation methods because it is limited by experimental site and automatic driving technology on real vehicles. This paper puts forward a miniature traffic model to simulate the actual traffic scene and achieves to verify the decision control of automatic lane-change scene. The miniature intelligent traffic scene contains miniature vehicles, simplified miniature road traffic environment, and wireless network communication. After testing the basic functions of the miniature traffic scene model, such as automatic lane change, lane keeping, and automatic following, a semi-physical simulation test of the traffic flow composed of the model vehicle and the virtual vehicle is carried out. The semi-physical simulation test includes vehicle-following test of hybrid-condition intelligent driver model, lane-change test of lane-change decision two-vehicle gaming model, and minimizing overall braking induced by lane changes. The results show that the feasibility of the method and of the lane-change decision two-vehicle gaming model of automatic lane change is better in terms of traffic safety, traffic efficiency, and homogeneity. Compared to the minimizing overall braking induced by lane-change model test, the test of lane-change decision two-vehicle gaming model improves 2.26% and 1.5% in the average speed and total driving distance, respectively. The standard deviation of the traffic speed of the lane-change decision two-vehicle gaming model was 28.57% lower than the minimizing overall braking induced by lane changes. Compared to pure simulation verification, the method considers the effects of actual sensor signals and actuator control, which is closer to the actual application.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Al-Omari, Zakaria, A. Hamzeh, Sadeq A. Hamed, A. Sandouk, and G. Aldahim. "A Mathematical Model for Minimizing Add-On Operational Cost in Electrical Power Systems Using Design of Experiments Approach." International Journal of Electrical and Computer Engineering (IJECE) 5, no. 5 (October 1, 2015): 948. http://dx.doi.org/10.11591/ijece.v5i5.pp948-956.

Повний текст джерела

Анотація:

One of the key functions of the Distribution System Operators (DSOs) of<br />electrical power systems (EPS) is to minimize the transmission and<br />distribution power losses and consequently the operational cost. This<br />objective can be reached by operating the system in an optimal mode which is performed by adjusting control parameters such as on-load tap changer (OLTC) settings of transformers, generator excitation levels, and VAR compensators switching. The deviation from operation optimality will result in additional losses and additional operational cost of the power system. Reduction of the operational cost increases the power system efficiency and provides a significant reduction in total energy consumption. This paper proposes a mathematical model for minimizing the additional (add-on) costs based on Design of Experiments (DOE). The relation between add-on operational costs and OLTC settings is established by means of regression statistical analysis. The developed model is applied to a 20-bustest network. The regression curve fitting procedure requires simulation experiments which have been carried out by the DigSilent PowerFactory 13.2 Program for performing network power flow. The results show the effectiveness of the model. The research work raises the importance the power system operation management of the EPS where the Distribution System Operator can avoid the add-on operational costs by continuous correction to get an operation mode close to optimality.

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Vo, Dieu Ngoc, Dung Anh Le, and Tu Phan Vu. "Particle swarm optimization with constriction factor for optimal reactive power dispatch." Science and Technology Development Journal 16, no. 2 (June 30, 2013): 89–101. http://dx.doi.org/10.32508/stdj.v16i2.1520.

Повний текст джерела

Анотація:

This paper proposes a simple particle swarm optimization with constriction factor (PSO-CF) method for solving optimal reactive power dispatch (ORPD) problem. The proposed PSO-CF is the conventional particle swarm optimization based on constriction factor which can deal with different objectives of the problem such as minimizing the real power losses, improving the voltage profile, and enhancing the voltage stability and properly handle various constraints for reactive power limits of generators and switchable capacitor banks, bus voltage limits, tap changer limits for transformers, and transmission line limits. The proposed method has been tested on the IEEE 30-bus and IEEE 118-bus systems and the obtained results are compared to those from other PSO variants and other methods in the literature. The result comparison has shown that the proposed method can obtain total power loss, voltage deviation or voltage stability index less than the others for the considered cases. Therefore, the proposed PSO-CF can be favorable solving the ORPD problem.

Стилі APA, Harvard, Vancouver, ISO та ін.

36

PHILLIPS, MICHAEL D., and BYUNG-RAE CHO. "A NONLINEAR MODEL FOR DETERMINING THE MOST ECONOMIC PROCESS MEAN UNDER A BETA DISTRIBUTION." International Journal of Reliability, Quality and Safety Engineering 07, no. 01 (March 2000): 61–74. http://dx.doi.org/10.1142/s0218539300000067.

Повний текст джерела

Анотація:

The selection of the process mean (target) is critically important since it directly affects the process defective rate, material cost, scrap or rework cost, and the loss to the customer due to the deviation of product performance. The goal is to determine the optimum process target based on minimizing total cost relating to product quality. For mathematical convenience, normal distributions have been traditionally assumed in solving this problem. Under practical situations, however, typical process distributions are often either positively or negatively skewed. Consequently, the normal distribution may not be ideal for many situations. In this paper, we consider a beta distribution which can be shaped and scaled to fit most skewed and symmetric process distributions. Furthermore, this paper uses a quality loss function to capture and quantify the quality loss from the customer's perspective. Finally, we develop an economic model for selecting the optimum process target. An example is given to illustrate the model.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Xing, Jian, Tianyao Hao, Ya Xu, and Zhiwei Li. "Integration of geophysical constraints for multilayer geometry refinements in 2.5D gravity inversion." GEOPHYSICS 81, no. 5 (September 2016): G95—G106. http://dx.doi.org/10.1190/geo2015-0565.1.

Повний текст джерела

Анотація:

We have explored the feasibility of estimating depths of multiple interfaces from gravity data. The strata are simulated by an aggregate of 3D rectangular prisms whose bottom depths are parameters to be estimated. In the inversion process, we have integrated geophysical constraints including the borehole information and the sharp condition described by the total variation function. The iterative residual function is also introduced to adjust the weighting of the estimated parameters so that layers of different depths have nearly equal likelihood for deviation. The inversion is processed by minimizing the Tikhonov parametric functional by the reweighted regularized conjugate gradient method. Inequality constraints are adopted to deal with the coupling of the interfaces. Synthetic tests show that such integration is conducive to restoring the multilayer depth distribution. Real data applications in Mariana confirm that the inversion method is effective in complex geologic settings in practice. We have also evaluated several issues that specifically deserve attention for obtaining satisfactory results in multilayer gravity inversion.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Belbachir, N., M. Zellagui, S. Settoul, C. Z. El-Bayeh, and B. Bekkouche. "Simultaneous optimal integration of photovoltaic distributed generation and battery energy storage system in active distribution network using chaotic grey wolf optimization." Electrical Engineering & Electromechanics, no. 3 (June 23, 2021): 52–61. http://dx.doi.org/10.20998/2074-272x.2021.3.09.

Повний текст джерела

Анотація:

Goal. The integration of photovoltaic distributed generations in the active distribution network has raised quickly due to their importance in delivering clean energy, hence, participating in solving various problems as climate change and pollution. Adding the battery energy storage systems would be considered as one of the best choices in giving solutions to the mentioned issues due to its characteristics of quick charging and discharging, managing the quality of power, and fulfilling the peak of energy demand. The novelty of the proposed work is the development of new multi-objective functions based on the sum of the three technical parameters of total active power loss, total voltage deviation, and total operation time of the overcurrent protection relay. Purpose. This paper is dedicated for solving the allocation problem of hybrid photovoltaic distributed generation and battery energy storage systems integration in the standard IEEE 33-bus and IEEE 69-bus active distribution networks. Methodology. The optimal integration of the hybrid systems is formulated as minimizing the proposed multi-objective functions by applying a newly developed metaheuristic technique based on various chaotic grey wolf optimization algorithms. The applied optimization algorithms are becoming increasingly popular due to their simplicity, lack of gradient information needed, ability to bypass local optima, and versatility in power system applications. Results. The simulation results of both test systems confirm the robustness and efficiency of the chaotic logistic grey wolf optimization algorithm compared to the rest of the algorithms in terms of convergence to the global optimal solution and in terms of providing the best and minimum multi-objective functions-based power losses, voltage deviation and relay operation time values. Practical significance. Recommendations have been developed for the use of optimal allocation of hybrid systems for practical industrial distribution power systems with the renewable energy sources presence.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

R, Karthi, Inigo Sherlin Joy G, and Jemima M. "Assess the Knowledge and Practice among Cardiac Nurses about Patient Safety after Cardiac Catheterization, Tamilnadu." International Journal of Research and Review 8, no. 4 (April 21, 2021): 220–25. http://dx.doi.org/10.52403/ijrr.20210429.

Повний текст джерела

Анотація:

Background: Cardiac catheterization is an invasive procedure which is used in the diagnosis and treatment of several cardiac diseases. It may lead to several major and minor complications which may contribute to morbidity and mortality. Early recognition of complications and proper care is logically tied to taking action to receive prompt treatment and thus minimizing further complications. Objectives: (i) To find out the level of knowledge and practice level of cardiac nurses related to patient safety after cardiac catheterization. (ii) To find the association between selected demographic variables with level of knowledge and practice of cardiac nurses regarding patient safety after cardiac catheterization. Method: A survey was conducted in 30 convenient samples with a pre-validated questionnaire and an observational tool was also used in assessing the quality of care provided. The total period of the study was from January to February 2020. The study population was staff nurses from cardiology medical intensive care unit and cardiology medical ward. Result: The findings shows that in the level of knowledge among 30 samples the level of knowledge frequency and percentages. Adequate 22(73%), moderately adequate 06(20%), inadequate 02(7%). Mean 7.53, standard deviation 1.33. In the level of practice among 30 samples the level of practice frequency and percentages. Good 20(67%), average 08(27%), poor 02(6%). Mean 15.6, standard deviation 3.21. The findings shows that there is a significant association on knowledge level between demographic variables Additional qualification and Total year of experience at p<0.05. In practice there is a significant association on practice level between demographic total year of experience at p<0.05. Conclusion: The Study concluded that most of the Staff nurses has adequate knowledge and good practice regarding care of patients after cardiac catheterization and there is an association on level of knowledge with demographic variables like additional qualification and total year of experience and in practice there is association with total year of experience. Keywords: cardiac nurses, patient safety, cardiac catheterization.

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Mubarak, Hamza, Munir Azam Muhammad, Nurulafiqah Nadzirah Mansor, Hazlie Mokhlis, Shameem Ahmad, Tofael Ahmed, and Muhammad Sufyan. "Operational Cost Minimization of Electrical Distribution Network during Switching for Sustainable Operation." Sustainability 14, no. 7 (April 1, 2022): 4196. http://dx.doi.org/10.3390/su14074196.

Повний текст джерела

Анотація:

Continuous increases in electrical energy demand and the deregulation of power systems have forced utility companies to provide high-quality and reliable services to maintain a sustainable operation and reduce electricity price. One way to continue providing the required services while simultaneously reducing operational costs is through minimizing power losses and voltage deviation in the distribution network. For this purpose, Network Reconfiguration (NR) is commonly adopted by employing the switching operation to enhance overall system performance. In the past, work proposed by researchers to attain switching sequence operation was based on hamming distance approach. This approach caused the search space to grow with the increase in total Hamming distance between the initial and the final configuration. Therefore, a method is proposed in this paper utilizing a Mixed Integer Second Order Cone Programming (MISOCP) to attain optimal NR to address this issue. The Hamming dataset approach is opted to reduce search space by considering only radial configuration solutions to achieve an optimal switching sequence. In addition, a detailed economic analysis has been performed to determine the saving after the implementation of the proposed switching sequence. The effectiveness of the proposed technique is validated through simulations on IEEE 33-bus distribution network and a practical 71-bus network in Malaysia. The result shows that the proposed method determined the optimal network configuration by minimizing the power losses for the 33 bus and 71-bus system by 34.14% and 25.5% from their initial configuration, respectively to maintain sustainable operation.

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Taranenko, Yuri, Ruslan Mygushchenko, Olga Kropachek, Grigoriy Suchkov, and Yuri Plesnetsov. "Minimization of errors in discrete wavelet filtering of signals during ultrasonic measurements and testing." Ukrainian Metrological Journal, no. 4 (December 30, 2021): 57–62. http://dx.doi.org/10.24027/2306-7039.4.2021.250433.

Повний текст джерела

Анотація:

Error minimizing methods for discrete wavelet filtering of ultrasonic meter signals are considered. For this purpose, special model signals containing various measuring pulses are generated. The psi function of the Daubechies 28 wavelet is used to generate the pulses. Noise is added to the generated pulses. A comparative analysis of the two filtering algorithms is performed. The first algorithm is to limit the amount of detail of the wavelet decomposition coefficients in relation to signal interference. The minimum value of the root mean square error of wavelet decomposition signal deviation which is restored at each level from the initial signal without noise is determined. The second algorithm uses a separate threshold for each level of wavelet decomposition to limit the magnitude of the detail coefficients that are proportional to the standard deviation. Like in the first algorithm, the task is to determine the level of wavelet decomposition at which the minimum standard error is achieved. A feature of both algorithms is an expanded base of discrete wavelets ‒ families of Biorthogonal, Coiflet, Daubechies, Discrete Meyer, Haar, Reverse Biorthogonal, Symlets (106 in total) and threshold functions garotte, garrote, greater, hard, less, soft (6 in total). The model function uses random variables in both algorithms, so the averaging base is used to obtain stable results. Given features of algorithm construction allowed to reveal efficiency of ultrasonic signal filtering on the first algorithm presented in the form of oscilloscopic images. The use of a separate threshold for limiting the number of detail coefficients for each level of discrete wavelet decomposition using the given wavelet base and threshold functions has reduced the filtering error.

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Sanford, Joseph R., Rebecca A. Larson, and Matthew F. Digman. "Assessing Certified Manure Analysis Laboratory Accuracy and Variability." Applied Engineering in Agriculture 36, no. 6 (2020): 905–12. http://dx.doi.org/10.13031/aea.14214.

Повний текст джерела

Анотація:

HighlightsManure analysis proficiency laboratories were assessed for accuracy and precision.Total nitrogen analysis was accurate and precise and is a strength of industry.Ammonium analysis resulted in most variability in laboratory results.Phosphorus and potassium mean comparison indicated significant differences between lab results.Abstract.Nutrient management planning (NMP) is an effective method for ensuring proper nutrient applications to agricultural fields. At livestock facilities, quantifying manure nutrient content is crucial for producers to obtain accurate and precise data to properly apply nutrients to the field to optimize crop yields while minimizing nutrient losses to the environment. In this study, eight manure analysis proficiency program (MAP) certified laboratories each received six replicates of four manure samples (two dairy and two swine) and analyzed for total solids (TS), total nitrogen (TN), ammoniacal nitrogen (NH4-N), phosphate (P2O5), and potash (K2O). Laboratories were compared using the MAP robust statistics comparison approach and a one-way ANOVA using laboratory means. Total nitrogen analysis had high precision and accuracy across laboratories selected for analysis. However, laboratories had less accuracy and precision in determining NH4-N concentrations. Additionally, while P2O5 and K2O met MAP standards for accuracy and precision, there was concerns for reading accuracy, as the median absolute deviation (MAD) to overall median ratio was high (ranging from 5.9% to 14.4%) and many of the laboratory means were statistically different. Keywords: Laboratory variability, Manure, Nutrient analysis.

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Saleh, Ayat Ali, Tomonobu Senjyu, Salem Alkhalaf, Majed A. Alotaibi, and Ashraf M. Hemeida. "Water Cycle Algorithm for Probabilistic Planning of Renewable Energy Resource, Considering Different Load Models." Energies 13, no. 21 (November 5, 2020): 5800. http://dx.doi.org/10.3390/en13215800.

Повний текст джерела

Анотація:

This work introduces multi-objective water cycle algorithm (MOWCA) to find the accurate location and size of distributed energy resource (DERs) considering different load models for two seasons (winter, and summer). The impact of uncertainties produced from load and renewable energy resource (RES) such as wind turbine (WT) and photovoltaic (PV) on the performance of the radial distribution system (RDS) are covered as this is closer to the real operation condition. The point estimate method (PEM) is applied for modeling the RES uncertainties. An optimization technique is implemented to find the multi-objective optimal allocation of RESs in RDSs considering uncertainty effect. The main objectives of the work are to maximize the technical, economic and environmental benefits by minimizing different objective functions such as the dissipated power, the voltage deviation, DG cost and total emissions. The proposed multi-objective model is solved by using multi-objective water cycle algorithm (MOWCA), considering the Pareto criterion with nonlinear sorting based on fuzzy mechanism. The proposed algorithm is carried out on different IEEE power systems with various cases.

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Ahungwa, J. I., E. C. Odiaka, and G. T. Ahungwa. "Effect of Agricultural Extension Services in Minimizing Post-Harvest Losses of Yam Produce in Benue State, Nigeria." BADEGGI JOURNAL OF AGRICULTURAL RESEARCH AND ENVIRONMENT 3, no. 3 (December 1, 2021): 67–74. http://dx.doi.org/10.35849/bjare202103014.

Повний текст джерела

Анотація:

The study assessed the effect of agricultural extension services in minimizing post-harvest losses of yam in Benue State. Multistage sampling procedure was used to select 240 yam producers. Data were collected using structured questionnaire. Descriptive statistics such as frequency, mean and standard deviation, post-harvest management coefficient (PMC) and binary logistic regression (BLR) were used to analyse the data. Results on producers’ capabilities to manage PHLs revealed that 58.5% of the total yam produce (PMC = 0.585) was preserved while a sizeable proportion (41.5%) of losses were incurred after harvest. The availability of agricultural extension services showed that, the provision of agricultural information ( ̅ = 1.54), access to agricultural markets ( ̅ = 1.50) and facilitation of the formation of producers’ self-help groups ( ̅ = 1.50) were the prime extension services rendered in the study area. Empirical result on the effect of agricultural extension services on PHLs management revealed that the number of agricultural extension services (P ≤ 0.01) and access to agricultural credit (P ≤ 0.01) exerted positive and significant influence on PHLs management. Also, the level of producers’ education (P ≤ 0.1) enhanced significantly and consistently, their capabilities to minimize PHLs. Conversely, the number of agricultural information sources (P ≤ 0.1) exerted negative and significant influence on yam producers’ capabilities to manage post-harvest losses. The study concludes that agricultural extension services are potent in the management of post-harvest losses. The study thus recommends the provision of agricultural extension service by service agencies, given that the capacities of yam producers’ in minimizing post-harvest losses could be enhanced significantly and consistently with increase in the numbers of agricultural extension services at their disposal, and the enhancement of access to agricultural extension services by yam producers, individually and cooperatively, to curtail the incidences incidence of post-harvest losses on yam.

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Avdeev, S. V. "Mathematical model of turbofan engine weight estimation taking into account the engine configuration and size." VESTNIK of Samara University. Aerospace and Mechanical Engineering 20, no. 1 (April 20, 2021): 5–13. http://dx.doi.org/10.18287/2541-7533-2021-20-1-5-13.

Повний текст джерела

Анотація:

The paper presents a new correlation-regression model of estimating the turbofan engine weight considering the effect of the engines design schemes and dimensions. The purpose of this study was to improve the efficiency of the conceptual design process for aircraft gas turbine engines. Information on 183 modern turbofan engines was gathered using the available sources: publications, official websites, reference books etc. The statistic information included the values of the total engine air flow, the total turbine inlet gas temperature, the overall pressure ratio and the bypass ratio, as well as information on the structural layout of each engine. The engines and the related statistics were classified according to their structural layout and size. Size classification was based on the value of the compressor outlet air flow through the gas generator given by the parameters behind the compressor. Depending on the value of this criterion, the engines were divided into three groups: small-sized, medium-sized gas turbine engines, and large gas turbine engines. In terms of the structural layout, all engines were divided into three groups: turbofan engines without a mixing chamber, engines with a mixing chamber and afterburning turbofan engines. Statistical factors of the improved weight model were found for the respective groups of engines, considering their design and size. The coefficients of the developed model were determined by minimizing the standard deviations. Regression analysis was carried out to assess the quality of the developed model. The relative average error of approximation of the developed model was 8%, the correlation coefficient was 0,99, and the standard deviation was 10,2%. The model was found to be relevant and reliable according to Fisher's test. The obtained model can be used to assess the engine weight at the stage of conceptual design and for its optimization as part of an aircraft.

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Pavlov, Oleksandr, Oleksandra Vozniuk, and Olena Zhdanova. "THE LINEAR-FRACTIONAL PROGRAMMING PROBLEM UNDER UNCERTAINTY CONDITIONS." Bulletin of National Technical University "KhPI". Series: System Analysis, Control and Information Technologies, no. 1 (5) (July 12, 2021): 20–28. http://dx.doi.org/10.20998/2079-0023.2021.01.04.

Повний текст джерела

Анотація:

This paper addresses the problem of linear-fractional programming under uncertainty. The uncertainty here is understood as the ambiguity of the coefficients’ values in the optimized functional. We give two mathematical formulations of the problem. In the first one, the uncertainty refers to the numerator: there are several sets of objective function coefficients, each coefficient can determine the numerator of the problem’s criterion at the stage of its solution implementation. The uncertainty in the second formulation refers to the denominator of the functional. We propose several compromise criteria for evaluating solutions to the problem we consider. We study the following two criterions in detail: 1) finding a compromise solution in which the deviation of the values of the partial functionals from their optimal values is within the specified limits; 2) finding a compromise solution according to the criterion of minimizing the total weighted excess of the values of partial functionals in relation to the specified feasible deviations from their optimal values (the values of concessions). We formulate an auxiliary linear programming problem to find a compromise solution to the linear-fractional programming problems by these two criteria. The constraints of the auxiliary problem depend on the optimization direction in the original problem. We carried out a series of experiments of four types to study the properties of the problem. The purposes of the experiments were: 1) to study how changes in the values of the specified feasible deviations of partial objective functions impact the values of actual deviations and the values of concessions; 2) to study how changes in the expert weights of partial objective functions impact the values of actual deviations and the values of concessions for the compromise solutions we obtain. We propose in this work the schemes of experiments and present their results in graphical form. We have found that the obtained relations depend on the optimization direction in the original problem. Keywords: optimization, uncertainty, convolution, linear-fractional programming, linear programming problem, compromise solution

Стилі APA, Harvard, Vancouver, ISO та ін.

47

Sohrabi, Arya, Mir Saman Pishvaee, Ashkan Hafezalkotob, and Shahrooz Bamdad. "A multi-attribute model to optimize the price and composition of prepaid mobile Internet plans." Journal of Enterprise Information Management 33, no. 5 (July 16, 2020): 1257–91. http://dx.doi.org/10.1108/jeim-09-2019-0279.

Повний текст джерела

Анотація:

PurposePrepaid mobile Internet is one of the most profitable services that are composed of multiple attributes. The overall utility of Internet service can be broken down into the sum of the utility of individual attribute levels. Based on the multi-attribute theory, rational consumers choose the service that yields the highest utility from a number of possible alternatives. Determining the optimal attribute levels that satisfy consumers' preferences and maximize the total revenue of the firm is a challenging multi-attribute decision problem for any mobile operator. When designing mobile Internet services, adopting a robust composition of services against different realizations of competitors' strategies can bring advantages for network operators. The purpose of this study is to determine the optimal attribute levels of prepaid mobile Internet packages with the aim of maximizing the total revenue of the firm by considering the paradigms of multi-attribute utility theory about consumer choices and the issue of uncertainty in counterpart services offered by the competitors.Design/methodology/approachThis paper formulates the problem of multi-attribute pricing and design of mobile Internet plans in a competitive environment by developing deterministic and robust scenario-based mathematical models and considering the paradigms of multi-attribute utility theory about consumer choices. The proposed robust scenario-based models are based on three different paradigms, including maximizing expected revenue, minimizing the negative deviation from expected revenue and minimizing the maximum regret. A comprehensive numerical analysis is conducted to evaluate and compare the efficiency of the proposed models.FindingsThe evaluations reveal that deploying recourse policy can result in higher revenue for the firm when facing uncertainty. By doing sensitivity analysis, this paper shows that consumer preferences for brand attribute and consumers' purchase frequency can influence the revenue of network operators.Originality/valueThis paper develops a novel deterministic multi-attribute product line design (PLD) model to address the problem of determining the price and composition of prepaid mobile Internet plans. Furthermore, the issue of uncertainty in counterpart services offered by the competitors is studied for the first time in the PLD literature.

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Gogstad, G. O., K. H. Dahl, A. Christophersen, and A. Bjerke. "Turbidimetric determination of prothrombin time by clotting in a centrifugal analyzer." Clinical Chemistry 32, no. 10 (October 1, 1986): 1857–62. http://dx.doi.org/10.1093/clinchem/32.10.1857.

Повний текст джерела

Анотація:

Abstract Two thromboplastin reagents ("Thrombotest" and "Normotest Automated") were used in evaluation of an automated method for determination of prothrombin time based on turbidimetric measurement of clot formation in a centrifugal analyzer. We used 60 plasma samples from patients with various diseases or being treated with oral anticoagulant and 16 normal plasma samples. Prothrombin times were calculated by a computer connected to the analyzer, a reading being made at either a certain per cent increase in total absorbance or a fixed absorbance increase. Both correlated well with the manual method (r = 0.98-0.99). The reading points best fitting the manually obtained data were estimated by minimizing the residual sum of squares in regression analyses performed at various absorbance increases. The per cent reading was better in this respect. Normotest Automated could be nearly perfectly related to the manual method, whereas Thrombotest showed a (negligibly) small deviation. Reproducibility was good within run (CV less than or equal to 3.2%) as well as between batch of the reagents, as assessed from variation in INR (CV less than or equal to 4.9%). We conclude that turbidimetry of clot formation may be validly used in automation of the prothrombin-time test. The equipment needed and the total time per analysis are about as for chromogenic substrate methods, but reagent cost is considerably lower.

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Lv, Zhenyu, Zaijun Wu, Xiaobo Dou, Min Zhou, and Wenqiang Hu. "Distributed Economic Dispatch Scheme for Droop-Based Autonomous DC Microgrid." Energies 13, no. 2 (January 14, 2020): 404. http://dx.doi.org/10.3390/en13020404.

Повний текст джерела

Анотація:

In this paper, a distributed economic dispatch scheme considering power limit is proposed to minimize the total active power generation cost in a droop-based autonomous direct current (DC) microgrid. The economical dispatch of the microgrid is realized through a fully distributed hierarchical control. In the tertiary level, an incremental cost consensus-based algorithm embedded into the economical regulator is utilized to search for the optimal solution. In the secondary level, the voltage regulator estimating the average voltage of the DC microgrid is used to generate the voltage correction item and eliminate the power and voltage oscillation caused by the deviation between different items. Then, the droop controller in the primary level receives the reference values from the upper level to ensure the output power converging to the optimum while recovering the average voltage of the system. Further, the dynamic model is established and the optimal communication network topology minimizing the impact of time delay on the voltage estimation is given in this paper. Finally, a low-voltage DC microgrid simulation platform containing different types of distributed generators is built, and the effectiveness of the proposed scheme and the performance of the optimal topology are verified.

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Pahari, Smriti, and Sushma Bhattarai. "An Assessment of Forest Product Harvesting in Community Forests: A Case from Community Forest of Mid-hills, Nepal." Forestry: Journal of Institute of Forestry, Nepal 17 (December 23, 2020): 67–82. http://dx.doi.org/10.3126/forestry.v17i0.33636.

Повний текст джерела

Анотація:

Proper harvesting of forest products is crucial for sustainable management but due to low level of skill in and awareness of harvesting, forest is deteriorating and harvesting forest products is wasteful. As harvesting is one of the important factors in minimizing waste and damage and achieving forest sustainability, this study was essential. This case from community forest (CF) of mid-hills region demonstrated the status of existing harvesting practices, tools and techniques used and recommended appropriate mechanism for improving such practices. Semi-structured questionnaire survey was performed with 40% of the total households, five key informant interviews and field observations during the harvesting process at the study site for gathering data. Data were analyzed using descriptive statistics and presented in charts and tables. The study revealed the use of traditional harvesting methods and conventional tools like sickle, bill-hook, and axe but limited use of modern tools. Deviation from the operation plan during block selection and harvesting of trees were observed. Appropriate tools and training to users along with regular monitoring by forest officials are needed. This study will help policy makers, planners and forest officials to make necessary provisions for improving harvesting practice in community forests of Nepal.

Стилі APA, Harvard, Vancouver, ISO та ін.

Статті в журналах з теми "Minimizing total deviation"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями