OPTIMAL DESIGN OF BINARY WEIGHTED k-OUT-OF-n SYSTEMS

2008 ◽  
Vol 15 (05) ◽  
pp. 425-440 ◽  
Author(s):  
WEI LI ◽  
MING J. ZUO ◽  
YI DING
Keyword(s):  
Optimal Design ◽  
System Reliability ◽  
System Size ◽  
Optimization Models ◽  
Total System ◽  
Total Cost ◽  
Total Utility ◽  
Need To Evaluate ◽  
Expected Total Cost ◽  
Binary Weighted

In this paper, we consider the optimal design of the binary weighted k-out-of-n system. The binary weighted k-out-of-n: G system works if and only if the total utility of all working components is at least k. In the design process, we need to evaluate system reliability repetitively. The universal generating function (UGF) approach is used for this purpose when the system size is small or moderate. When the size of the system is large, the recursive approach is used, which is more efficient. Two optimal models are formulated. One is to minimize the expected total cost while guaranteeing the system reliability higher than a pre-specified value; the other is to maximize the system reliability with the constraints on total system cost. Genetic algorithms (GA) and Tabu Search (TS) methods are both used to solve the proposed optimization models. Since the key to a good TS algorithm is usually quite problem-specific policies and memory structures, there is no existing general TS tool available. Therefore more details of the TS approach used in this paper are discussed than the GA approach. The results obtained with these two methods are compared. The results illustrate that both methods are powerful tools for solving these kinds of problems. However TS is more efficient than GA in computation. The materials in this paper have been published in 19.

scholarly journals Integrating human factors aspects into performance optimization models of a serial assembly system

2021 ◽  
Author(s):  
Ahmad Sobhani
Keyword(s):  
Markov Chain ◽  
Performance Optimization ◽  
Employee Health ◽  
Working Environment ◽  
Optimization Models ◽  
Assembly System ◽  
Health State ◽  
Total Cost ◽  
Work Related ◽  
Analytical Phase

This dissertation investigates the effects of human factors (HF) of the working environment on the performance of an operation system. Poor HF design of the workplace interrupts the balance of the working environment and reduces employees' overall work performance creating a substantial economic burden on organizations. This thesis focuses on integrating HF aspects into performance optimization models of the serial system. For this reason, a modeling framework has been developed for hierarchical consideration of HF consequences at the individual, workstation and system levels. The developed framework provides a road map for the three analytical phases of this PhD research. In the first analytical phase, a two-state Markov chain is developed to quantify the connection between Work-related Ill Health (WIH) risk factors (ergonomic conditions in the workplace) and employee health-state in a probabilistic way. Subsequently, an optimization model is developed to minimize the total cost of the assembly system with regard to employee health-related productivity loss. Numerical results indicate that there is between 0.5% and 8% difference in the optimal cost of the system with and without including HF effects. In the second analytical phase, a three health-state Markov chain models the connection between HF aspects of the workplace and the employees' work-related productivity and quality variations. Results show between 0.02% and 32% increase for the optimal total cost when both employee productivity and quality losses due to poor HF design of the workplace are integrated into the optimization model. In the third analytical phase, the uncertainty involved in customer demand is considered by developing a two-regime switching model, using a pentanomial lattice. The developed modeling approach investigates the effects of both work-related employee performance variation and demand behavior on the optimal cost of the serial assembly system. Results show that a prediction of the demand distribution throughout the product life cycle is necessary to reduce the over/under cost estimation of the system, due to the stochastic behavior of the demand. This research opens a new window for considering HF intervention not only as occupational health and safety but also as operation improvement method leading to design safer and more efficient systems.

scholarly journals Step-Wise Group Screening Designs with Unequal A-Priori Probabilities and Errors in Observations

2003 ◽  
Vol 8 (2) ◽  
pp. 153
Author(s):  
M.M. Manene
Keyword(s):  
Cost Function ◽  
Group Size ◽  
A Priori ◽  
Expected Number ◽  
Total Cost ◽  
Screening Designs ◽  
Expected Total Cost

The performance of step-wise group screening with unequal a-priori probabilities in terms of the expected number of runs and the expected maximum number of incorrect decisions is considered. A method of obtaining optimal step-wise designs with unequal a-priori probabilities is presented for the case in which the direction of each defective factor is assumed to be known a -priori and observations are subject to error. An appropriate cost function is introduced and the value of the group size which minimizes the expected total cost is obtained.  

Optimization of Leased Equipment Maintenance Policy Based on History Failure Data

2021 ◽  
pp. 2150030
Author(s):  
Ke Dong ◽  
Kehong Chen
Keyword(s):  
Power Law ◽  
Cost Model ◽  
Maintenance Strategy ◽  
Maintenance Policy ◽  
Power Law Process ◽  
Total Cost ◽  
Cost Rate ◽  
Failure Data ◽  
Expected Total Cost ◽  
The Cost

We propose a maintenance policy for new equipment on a repair-refund maintenance strategy in this paper and derive the optimal lease period from the lessor’s perspective based on independent and identical distribution of historical failure data which obey power law process. The cost model of a full refund and a proportional refund is studied, and the corresponding optimal leasing period is determined by reducing the expected total cost rate to the largest extent. We use a numerical example to illustrate the proposed cost model and analyze the sensitivity of related parameters. Furthermore, we show that the proportional refund policy is preferable than a full refund to the lessor. Finally, according to the simulation outcome, the proposed methods are effective and instructions for lessor in regard to equipment lease are provided.

Implementation of Semi-Heuristic Reasoning for Boundedness Analysis of Design Optimization Models

1987 ◽  
Author(s):  
J. R. J. Rao ◽  
P. Y. Papalambros
Keyword(s):  
Optimal Design ◽  
Heuristic Search ◽  
Optimization Models ◽  
Programming Environment ◽  
Initial Model ◽  
Active Set ◽  
Design Models ◽  
Active Set Strategy ◽  
Reasoning System ◽  
Global Boundedness

Abstract A production system performing global boundedness analysis of optimal design models has been implemented in the OPS5 programming environment. The system receives as input an initial model monotonicity table and derives global facts about boundedness and constraint activity using monotonicity principles. Additional facts may be discovered by heuristic search of implicit elimination sequences that examine boundedness of reduced models with active constraints eliminated. The global facts generated automatically by this reasoning system can be used either for a global solution, or for a combined local-global active set strategy.

Thermoeconomic Analysis of a Combined Natural Gas Cogeneration System With a Supercritical CO2 Brayton Cycle and an Organic Rankine Cycle

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Zhen Pan ◽  
Mingyue Yan ◽  
Liyan Shang ◽  
Ping Li ◽  
Li Zhang ◽  
...  
Keyword(s):  
Supercritical Co2 ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Inlet Temperature ◽  
Total System ◽  
Brayton Cycle ◽  
Exhaust Gas ◽  
Total Cost ◽  
Cogeneration System ◽  
Isentropic Efficiency

Abstract This paper proposes a new type of Gas Turbine Cycle-supercritical CO2 Brayton/organic Rankine cycle (GT-SCO2/ORC) cogeneration system, in which the exhaust gas from gas-fired plants generates electricity through GT and then the remaining heat is absorbed by the supercritical CO2 (SCO2) Brayton cycle and ORC. CO2 contained in the exhaust gas is absorbed by monoethanolamine (MEA) and liquefied via liquified natural gas (LNG). Introducing thermodynamic efficiencies, thermoeconomic analysis to evaluate the system performance and total system cost is used as the evaluation parameter. The results show that the energy efficiency and exergy efficiency of the system are 56.47% and 45.46%, respectively, and the total cost of the product is 2798.38 $/h. Moreover, with the increase in air compressor (AC) or gas turbine isentropic efficiency, GT inlet temperature, and air preheater (AP) outlet temperature, the thermodynamic efficiencies have upward trends, which proves these four parameters optimize the thermodynamic performance. The total system cost can reach a minimum value with the increase in AC pressure ratio, GT isentropic efficiency, and AC isentropic efficiency, indicating that these three parameters can optimize the economic performance of the cycle. The hot water income increases significantly with the increase in the GT inlet temperature, but it is not cost-effective in terms of the total cost.

Balance Error Scoring System Reliability and Validity When Performed With Ice Skates

2020 ◽  
pp. 1-5
Author(s):  
Jason P. Mihalik ◽  
Elizabeth F. Teel ◽  
Robert C. Lynall ◽  
Erin B. Wasserman
Keyword(s):  
System Reliability ◽  
Scoring System ◽  
Reliability And Validity ◽  
Adolescent Male ◽  
Hockey Players ◽  
Need To Evaluate ◽  
Balance Error Scoring System ◽  
Test Retest Reliability ◽  
Balance Error ◽  
Traditional Manner

In equipment-heavy sports, there is a growing need to evaluate players in the condition in which they participate. However, the psychometric properties of the Balance Error Scoring System (BESS) while wearing skates remains unknown. Seventy-four adolescent male hockey players completed the BESS with and without skates. A subset was reevaluated at the conclusion of the season. The BESS while wearing skates resulted in a mean of 15 more total errors than the traditional administration (t73 = 14.94, p < .001; ES = 1.95) and demonstrated low test-retest reliability. The BESS should be administered in the traditional manner (without skates).

Optimal Design of Agricultural Irrigation Systems Considering System Reliability

2013 ◽  
Vol 13 (6) ◽  
pp. 351-358 ◽  
Author(s):  
Young Jin Lee ◽  
Kyung Wan Kim ◽  
Doosun Kang ◽  
Young Hwa Kim
Keyword(s):  
Optimal Design ◽  
System Reliability ◽  
Agricultural Irrigation ◽  
Irrigation Systems

A MULTI-PERIOD INVENTORY MODEL FOR DETERIORATING ITEMS IN UNCERTAIN ENVIRONMENT

2013 ◽  
Vol 21 (supp01) ◽  
pp. 113-125 ◽  
Author(s):  
YUFU NING ◽  
LIMEI YAN ◽  
HUANBIN SHA
Keyword(s):  
Equivalent Form ◽  
Service Level ◽  
Deteriorating Items ◽  
Inventory Problem ◽  
Total Cost ◽  
Uncertain Variables ◽  
Holding Cost ◽  
Inventory Holding Cost ◽  
Expected Total Cost ◽  
Inventory Holding

A model is constructed for a type of multi-period inventory problem with deteriorating items, in which demands are assumed to be uncertain variables. The objective is to minimize the expected total cost including the ordering cost, inventory holding cost and deteriorating cost under constraints that demands should be satisfied with some service level in each period. To solve the model, two methods are proposed in different cases. When uncertain variables are linear, a crisp equivalent form of the model is provided. For the general cases, a hybrid algorithm integrating the 99-method and genetic algorithm is designed. Two examples are given to illustrate the effectiveness of the model and solving methods.

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