• Journal of Korean Society for Quality Management
• /
• v.21 no.2
• /
• pp.48-60
• /
• 1993

We have depended upon the quantitative analysis for productivity measurement. and excluded the qualitative analysis from productivity measurement. But I think that the qualitative analysis must be considered so as to get a effective productivity measurement This paper intened to establish improvement productivity measurement adopted quality cost of all the qualitative elements.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.26 no.1
• /
• pp.7-16
• /
• 2003

At present, company has to produce a product that consumer like with a competitive price, a good quality, and a fitting time to supply. Process control and quality control are very important to supply with a product uniformly and inexpensively. Process control is given much weight in the quality control in manufacturing system. Statistical process controls(SPC) that are used in process generally have major impact on manufacturing, product design activities, and process development potentially. Control charts in statistical process control method can be interpreted the data from quality characteristics in production process and discriminated between chance variation and assignable variation in process. In addition, control chart can be used to monitor the process output and detect when changes in the inputs are required to bring the process back to an in-control state. The models that relate the influential inputs to process outputs help determine the nature and magnitude of the adjustments required. In this paper, the characteristic of product quality is monitored by control chart during the machining process and construction of quality control cycle is considered to divide into two types in this case that different assignable causes lead to shifts having different magnitudes. Then we are intended to find a process shift magnitude which has economical quality cost policy and are considered to quality cost functions to find a process shift magnitude. Those costs are categorized into the well-known categories of prevention, appraisal, and internal failure and external failure. This paper ends with numerical examples that demonstrate the usefulness of the model.

• Journal of Korean Society for Quality Management
• /
• v.29 no.1
• /
• pp.101-112
• /
• 2001

In supply chain, the quality level of assembly factory depends on the quality levels of suppliers and it is very important to integrate efforts improving the quality levels between producer and suppliers, In this paper, we consider an integrated determination problem of quality specification levels of suppliers. The cost model is developed and the optimal policy under a specific model assumption is obtained. A numerical example is studied.

• Journal of Korean Society for Quality Management
• /
• v.17 no.1
• /
• pp.116-124
• /
• 1989

A multi-period production-inventory scheduling model, which extends the customary dynamic lot sizing model to the one for deteriorating items, is developed. The amount of deterioration during a period is assumed to be proportional to the on-hand inventory at the end of the period. It is futher assumed that the deterioration rates vary from period to period. In addtion, an expediting cost due to the delay of outstanding order is included and it is allowed to offset the order release date in advance, instead, in order to avoid incurring the cost. Finally, a quasi-WW algorithm corresponding to the Wagar-Whitin algorithm is proposed to obtain the optimal production-inventory schedules.

• Asia-Pacific Journal of Business
• /
• v.11 no.1
• /
• pp.17-26
• /
• 2020

Purpose - This paper studies the welfare impacts of behavior-based price discrimination (BBPD) when firms are asymmetric in quality improvement costs. Design/methodology/approach - To this end, we consider a differentiated duopoly model with an inherited market share, where firms first make quality decisions and then compete in prices according to the pricing scheme, namely, uniform pricing or BBPD. Findings - We show that BBPD increases social welfare relative to uniform pricing if the firms' cost gap is large enough. This is because BBPD induces more consumers to buy a high-quality product than under uniform pricing, and because a low-cost firm's profit loss from BBPD decreases as the cost difference increases. Research implications or Originality - Our analysis offers policy implications for markets where BBPD raises antitrust concerns, and quality competition prevails.

• International Journal of Quality Innovation
• /
• v.7 no.3
• /
• pp.15-23
• /
• 2006

A spare ordering policy is considered for planned maintenance. Introducing the ordering, uptime, downtime, inventory costs and salvage value, we derive the expected cost effectiveness. The problem is to determine jointly the ordering time for a spare and the preventive replacement time for the operating unit which maximize the expected cost effectiveness. Some properties regarding the optimal policy are derived, and a numerical example is included to explain the proposed model.

• Journal of Korean Society for Quality Management
• /
• v.17 no.2
• /
• pp.149-157
• /
• 1989

A one-upper warehouse n-lower retailer inventory model is discussed. The probability distribution of demand for a given perod is independent. The inventory holding cost is proportional to the number of unsold units and the cost of shortages is proportional to the number of shortages. In the event of a shortage, units are redistributed with a cost proportional to the number of units from the retailers which are a surplus at the end of the period. The optimum stock levels are obtained and the effects of redistribution are analized.

• Journal of Korean Society for Quality Management
• /
• v.18 no.1
• /
• pp.77-83
• /
• 1990

A model for the economic design of an pn control charts with an assignale cause is presented and the loss-cost function for control schemes using these charts is derived. By minimizing this function with respect to the three control variables, namely, the sample size, the sampling interval and acceptance number, the economically optimal control plan can be optained. The article shows what influence increasing or decreasing condition, according to changeability of the size of these factors, of expected cost can have on the economy when an attribute control chart is used.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.6
• /
• pp.969-978
• /
• 2016

Around the world are increasing the demand for ESS. Currently, the domestic is expected to benefit by operating ESS. In the domestic, it is expected to benefit from operations of the installed ESS because of the introduction of ESS less capacity. However ESS capacity to the maximum profit occurs is unknown. ESS is different from the charge-discharge characteristics and the reserve to replace, depending on the application. Therefore, it should be established in accordance with the ESS optimal capacity according to the purpose used because it can maximize the quality and efficiency of the electric energy. To the ESS optimal capacity estimation by the purpose used, It should compare the investment cost caused by ESS facility installation and operation cost caused by operating ESS. In this paper, the operation mathematical model for estimating marginal operation costs established. In operation mathematical model, operating cost is considered fuel cost and no-load cost start-up cost. Because no-load cost and start-up cost are not related to cost and power plant output, there are expressed an integer variable costs as a step function.

• Korean Management Science Review
• /
• v.19 no.2
• /
• pp.191-204
• /
• 2002

As the portion of information systems (IS) budget to the total government budget becomes greater, the cost estimation of IS development and maintenance projects is recognized as one of the most important problems to be resolved for scientific and efficient management of IS budget. Since IS budget makes much effect on the delivery time, quality and productivity of IS projects, the exact cost estimation is also necessary for the successful accomplishment of IS projects. The primary concern in the cost estimation of IS projects is software cost estimation, which requires the measurement of the size of softwares. There are two methods for sizing software : line-of-code approach, function point model. In this paper, we propose a function-point-based model for estimating software cost. The proposed model is derived by collecting about fifty domestic IT projects in public sector and analyzing their relationship between cost drivers and development effort. Since the proposed model is developed by simplifying the function point model that can be used only when detailed user requirements are specified, it can be also applied at project planning and budgeting phase.