Writing Problem and Hypothesis Statements for Engineering Research(45)

8/7/2019 Writing Problem and Hypothesis Statements for Engineering Research(45)

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Writing Problem and Hypothesis

Statements for Engineering Research(45) /

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Setting of work proposal :? ?

Work problem :?

Quantitative specification of problem :

? Importance of problem :

,?

Project need : ,?


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Work objective : ? Methodology to achieve objective

: ? Anticipated results :

? Contribution to field :

?


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As indispensable actuators for auto-focusing (AF) andzooming, stepping motors are extensively adopted in digital videocameras (DVCs). Following rising consumer demand for DVCs in theelectronic products market, enhanced properties and elevated functionsplay an increasing pivotal role in luring new customers. Despite their fast dynamic AF access, even the most advanced DVCsare limited in terms of low power consumption and inadequateoperational efficiency to satisfy consumer demand. Conventional AFactuators in DVCs are all stepping motors, subsequently limited by aslow dynamic AF speed, high power consumption low power efficiency.Moreover, noise interference from a stepping motor in a DVC is easilyrecorded into the digital films during AF operation.

For instance, the operational time for a typical AF linear actuator ina DVC is only 1/6th that of a conventional stepper motor. Additionally,the power consumption by using a linear actuator in a DVC is only1/3rd of that when using a conventional stepping motor for AF.Moreover, the operational efficiency by using a linear actuator in a DVCis only 1/2 that of a conventional steeping motor.


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Furthermore, the acoustic noise interference caused by using a linearactuator for AF in a DVC is lower than that when operated by aconventional stepping motor. Therefore, linear actuators are highlypromising alternatives to conventional stepping motors in DVCs.

Theoretically, conventional stepping motors are limitedin terms of their fixed resolution, possibly incurring errors when usingopen-loop control in AF operation. Such limitations lead to unclearCCD images in a DVC. In practice, a conventional stepping motor islarger than a linear actuator owing to the simple structure of the latter.

Additionally, the conventional stepping motor for AF system in a DVCleads to slow dynamic AF speed, high power loss and low operationalefficiency. Moreover, noise interference from a stepping motor is easilyrecorded into digital forms during AF operation. Therefore, a sliding motor control (SMC) method based on the positionestimation algorithm (PEA) must be developed for use in AF of thelinear actuator in a DVC to achieve low power consumption, highoperational efficiency and fast dynamic AF access characteristics.


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A sliding motor control (SMC) method based on theposition estimation algorithm (PEA) can be developed for use in AF ofthe linear actuator in a DVC to achieve low power consumption, highoperational efficiency and fast dynamic AF access characteristics.

To do so, a concrete and linear actuator with low powerconsumption and high operational efficiency can be manufactured for

AF in a DVC. A magneto-resistive (MR) encoder in the linear actuatorcan then be adopted for use as a position feedback sensor to acquirethe position of the moving part of the linear actuator in AF operation.Next, an interpolation chip can be embedded to enhance the resolutionof a linear actuator in a DVC, attain an enhanced image and avoid anincreasing prime cost of a DVC. Additionally, the PEA can bedeveloped from the MR encoder to determine accurately the position ofthe moving part of the linear actuator in a DVC.


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As anticipated, the proposed SMC method can offer an effectivemeans of positioning and controlling velocity owing to its many advantages,e.g., insensitivity to parameter variations, disturbance rejection and fastdynamic response. Hence, the SMC based on the PEA written in a single chipcan enhance control performance in order to increase focusing speed and

accuracy. Additionally, the proposed SMC method can be adopted tomanufacture a linear actuator with low power consumption and high operationalefficiency for AF operation in a DVC. The proposed PEA can also determineaccurately the position of a moving part of a linear actuator in a DVC.Moreover, the SMC method based on use of the PEA in AF operation in a DVCcan reduce AF access time by several microseconds and avoid the recording of

acoustic noise interference into the digital films. The proposedmethod is highly promising for use in manufacturing an efficient linear actuatorwith low power consumption and high operational efficiency for AF operation inDVC rapidly. Furthermore, the AF system with a linear actuator has a fastdynamic AF speed and limited acoustic noise interference.


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Inventory refers to the stock of any organizational-related item or resource. All firms maintaining an inventory supply cansatisfy demand with respect to product variation. However, a largeinventory may incur long product cycle times. Additionally, theproportion of inventory and setup costs of a production line to the totaloperational fund in a company is extremely high, highlighting theimportance of developing a more economic inventory order model tosatisfy production requirements. The economicproduction quantity (EPQ) model derives an optimal production lot sizethat minimizes overall inventory costs for a single item. However, asituation in which multiple items are scheduled on a single facility doesnot ensure a feasible EPQ solution for each individual item in order toprevent stock depletion during the production cycle. The rotation cyclepolicy assumes that exactly one setup is available for each productduring each cycle. Additionally, all products are manufactured in thesame sequence during each production cycle. Despite its feasibility,the rotation cycle approach is not optimal in terms of minimizing overallproduction costs.


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For instance, for product m1 with a productiontime twice that of m2, the rotation cycle obtains a feasible solution.Both products are manufactured once in a single cycle, with the totalcost significantly higher than the sum of two single optimal solutions.However, using a diagrammatic explanation, a solution can be easilyfound that produces m1 once and produces m2 twice during each cycle.The latter method is obviously better than the former is. The rotation cycle policy is developed to adjust EPQ whenmultiple items are scheduled on a single facility, as well as to adjust theproduction time of all products to the same frequency. Doing so canlead to the establishment of a simple and accessible formula. However,when products vary too widely in terms of manufacturing time, adoptingthe rotation cycle policy creates a feasible solution, but not optimal one,leading to a markedly higher cost as well. Therefore, aprocess optimization procedure must be developed, capable ofmodifying the production cycle time based on the rotation cycle method.


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A process optimization procedure can be developed,capable of modifying the production cycle time based on the rotationcycle method. During each cycle, products may have more than onesetup. A solution procedure can determine the appropriate cycle length,number of setups for each item, scheduling constraints and totalinventory cost function. Via this procedure, each item cycle can beclose to the prime solution derived from the EPQ model. To do so, the model framework can be devised in contrast with therotation cycle policy. The policy can be adjusted to identify how eachitem is related with respect to optimal cycle time. Feasibility of theproposed model can then be verified, with desired changes madeaccordingly. Next, a recycle time formula, conditions of modelconstraints and total cost formula can be established. Examining therule by iteration can allow us to analyze the rationality and validity ofthese models. Additionally, an actual example can demonstrate itsfeasibility, along with a comparison made to the solution of the primalrotation cycle. Moreover, sensitivity can be performed to demonstratehow alternation cycle time influences total cost.


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As anticipated, the proposed algorithm can resolve theEPQ and rotation cycle problem of multiple items for a productionfacility. According to the numerical analysis of a case study, theproposed procedure can reduce overall cost more than rotation cyclepolicy can. In doing so, the setup cost and setup time can beintegrated into the proposed algorithm. Additionally, production linefacilities can be upgraded by centralizing the idle times simultaneously,thus ensuring their efficiency, e.g., routine maintenance and flexibility inproduction scheduling. Importantly, the proposed procedurecan resolve problems involving multiple items for a single facility.Consequently, production management can construct a feasiblesolution under multiple items on a single facility. Additionally, a largerratio for multiple production time for one item to another implies morebenefits acquired for the proposed algorithm. Determining productionquintiles is often referred to as a trade-off problem, in which theformulae attempt to minimize cost, reduce inventory costs, enhanceproduct quality and increase corporate profits.


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Writing Problem and Hypothesis Statements for Engineering Research(45)

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