• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.11-17
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• 2012

Along with the recent trend toward increasing variety and shorter life of products in the market, evaluation of risk for economic investment alternatives is of practical importance in manufacturing companies. This paper assumes that each alternative is composed of demand volume and unit sales price as income factors, and unit variable cost and fixed cost as expense factors. The paper assumes that these four factors move worse from the originally expected values, toward the direction of decreasing profit. Values of these four factors are also assumed to fluctuate from year to year over the entire multi-period. By applying the analysis of the breakeven points to each of the four factors, safer area against these changes is represented on the two dimensional domain called normalized total-cost unit-cost domain. A practical numerical example is analyzed to verify the validity of the proposed method.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.4
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• pp.385-391
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• 2006

The estimated decommissioning cost of nuclear research reactor is calculated by applying a unit cost factor-based engineering cost calculation method on which classification of decommissioning works fitted with the features and specifications of decommissioning objects and establishment of composition factors are based. Decommissioning cost of nuclear research reactor is composed of labor cost, equipment and materials cost. Labor cost of decommissioning costs in decommissioning works are calculated on the basis of working time consumed in decommissioning objects. In this paper, the unit cost factors and work difficulty factors which are needed to calculate the labor cost in estimating decommissioning cost of nuclear research reactor are derived and figured out.

• Communications for Statistical Applications and Methods
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• v.7 no.3
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• pp.773-788
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• 2000

Statistical process control (SPC) and engineering process control (EPC) are based on different strategies for processes quality improvement. SPC reduces process variability by detecting and eliminating special causes of process variation. while EPC reduces process variability by adjusting compensatory variables to keep the quality variable close to target. Recently there has been needs for a process control proceduce which combines the tow strategies. This paper considers a combined scheme which simultaneously applies SPC and EPC techniques to reduce the variation of a process. The process model under consideration is an integrated moving average(IMA) process with a step shift. The EPC part of the scheme adjusts the process back to target at every fixed monitoring intervals, which is referred to a repeated adjustment scheme. The SPC part of the scheme uses an exponentially weighted moving average(EWMA) of observed deviation from target to detect special causes. A Markov chain model is developed to relate the scheme's expected cost per unit time to the design parameters of he combined control scheme. The expected cost per unit time is composed of off-target cost, adjustment cost, monitoring cost, and false alarm cost.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.5
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• pp.311-318
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• 2009

In previous study, a new allocation methodology of common cost on multi-product have been suggested. The aim of this study is to suggest the methodology that allocates an environment pollution cost including carbon emission cost to each cost of multi-product. For this study, a supposed multi-energy system composed of twenty kinds of systems was made. The multi-energy system produces eighteen kinds of outputs that are electricity, steam, hot water, chilled water, ice, warm air, and cooling air from seven kinds of energy source that are LNG, coil, geothermal energy, sun heat, hydrogen, bio-mass, and waste. The new methodology was applied to the multi-energy system in order to allocate the environment pollution cost to each production cost, and twenty seven equations were induced. From this result, it is concluded that this methodology can estimate each unit cost and allocate each cost flow in any product of any energy system.

• Journal of Korean Society for Quality Management
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• v.19 no.2
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• pp.117-124
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• 1991

In this paper, it is assumed that a system is composed of an essential unit and a nonessential unit. During the running of the system, an essential unit is replaced at periodic replacement time T or at nth failure of essential unit whichever occurs first. Nonessential unit is replaced at its failure and at the replacement of essential unit. This paper derive optimal replacement period which minmises the total expected cost for replacement. The unimodality of totoal maintenance cost function is proved under the assumption that hazard rate of each component is continuous and monotone increasing failure rate(IFR). Based on this condition, it is shown that the optimal replacement period is finite and unique.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.63-70
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• 2003

It is very important to improve the insulation performance of curtain wall anchoring unit since it is composed of materials with high thermal conductivity, such as aluminium, steel and so on. This study aims to evaluate the heating energy performance and economical efficiency of various alternatives which are different in position and material of insulation. As results, alternative of inserting the urethane washer & pad and coating the anchoring unit with urethane foam can improve the heating energy performance and L.C.C(Life Cycle Cost) by 6.33% and 0.95%, respectively, as compared with the existing case.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.15.2-15.2
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• 2009

Manufacturing of printed electronics using printing technology has begun to get into the hot issue in many ways due to the low cost effectiveness to existing semi-conductor process. This technology with both low cost and high productivity, can be applied in the production of organic thin film transistor (OTFT), solar cell, radio frequency identification (RFID) tag, printed battery, E-paper, touch screen panel, black matrix for liquid crystal display (LCD), flexible display, and so forth. The emerging technology to manufacture the products in mass production is roll-to-roll printing technology which is a manufacturing method by printings of multi-layered patterns composed of semi-conductive, dielectric and conductive layers. In contrary to the conventional printing machines in which printing precision is about $50~100{\mu}m$, the printing machines for printed electronics should have a precision under $30{\mu}m$. In general, in order to implement printed electronics, narrow width and gap printing, register of multi-layer printing by several printing units, and printing accuracy of under $30{\mu}m$ are all required. We developed the roll-to-roll printing equipment used for printed electronics, which is composed of un-winder, re-winder, tension measurement system, feeding units, dancer systems, guide unit, printing unit, vision system, dryer units, and various auxiliary devices. The equipment is designed based on cantilever type in which all rollers except printing ones have cantilever types, which could give more accurate machine precision as well as convenience for changing rollers and observing the process.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.2
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• pp.170-175
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• 2010

Maintaining a complex repairable system can be achieved by repairing, replacing, or any other activities. This paper proposes a joint optimization policy that is composed with ordering and replacing under minimal repair for the complex system. For this purpose, we derive the expected cost due to the minimal repair, ordering, downtime, inventory costs, and salvage value of units that follow generally distribution. Some properties about the optimum ordering policy that are suggested for our purpose shows that the optimum ordering policy minimizing the expected cost is either one of the two typical policies : (1) the original unit is replaced as soon as the ordered spare is delivered, or (2) the delivered spare is used as inventory part until the original unit fails.

• Journal of Sensor Science and Technology
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• v.15 no.1
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• pp.40-46
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• 2006

This paper presents a novel fiber optic accelerometer system for monitoring vibration of large-size structures. The system is composed of one (or multiple) sensor head, a light control unit and a signal processing unit. The sensing mechanism of the sensor head is based on a novel integration of the moire fringe phenomenon with fiber optics to achieve a robust performance in addition to its immunity to EM interference, easy cabling, and low cost. In this paper, a prototype of the fiber optic accelerometer system has been developed successfully. A low-cost light control unit has been developed to drive the system's optic and electronic components. A unique algorithm has also been developed to derive the sensor's acceleration from the raw signals of the light control unit; it is implemented via a separate signal processing unit. Finally, the shaking table tests successfully demonstrate the performance and the potential of the moire fringe fiber optic sensor system to monitor the health of civil infrastructures.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.49-52
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• 2003

Two types of ozone monitors using UV absorption method were tried in consideration of cost of the monitor and precision in measuring. The high concentration ozone monitor for high concentration real time ozone monitoring from ozone generator was composed of a low pressure mercury lamp as UV source, a photo multiplier tube as UV detector and signal processing unit for the most part. This structure could be very useful for low price high concentration ozone monitor due to simple system structure and fairly good monitoring characteristics. The developed system showed good linear output characteristics to ozone in the measuring concentration range of 0.05 and 2 wt.%. For accuracy ambient ozone monitoring in ambient in ppm level, the system composed of a high power pulsed xenon lamp as UV source, an optical spectrometer with a high sensitivity linear CCD array as UV detector and signal processing unit in brief speaking was proposed our study for the first time in the world. The developed system showed good linearity and sensitivity in relative low measuring range between 10ppm and 10,000ppm, and showed some feasibility of high resolution ozone monitor using CCD array as photodetector.