• The Research Journal of the Costume Culture
• /
• v.8 no.1
• /
• pp.30-39
• /
• 2000

The purpose of this study were to 1) identify types and levels of production environments, 2) classify apparel manufacturers based on production environments and 3) investigate relationship between characteristics of apparel manufacturers and production environment. Apparel manufacturer's characteristics included product line and the number of employees. For this study, the questionnaires were administered to 215 apparel manufacturers in seoul and Kyung-gi region from Feb. to Mar. 1998. Employing a sample of 201, data were analyzed by factor analysis, descriptive statistics, cluster analysis, cluster analysis, discriminant Analysis, and multivariate analysis of variance. The following are the results of this study : 1. The production environment was identified as three types such as complexity of product environment, uncertainty of demand/supply environment and uncertainty of worker environment. 2. Based on three types of the production environment, apparel manufacturers were classified into stable group, uncertain group and complicated group. 3. With respect to product line, men's wear manufacturers were lied the most high complexity of product environment, casual wear and knit wear were lied the most frequently uncertainty of worker environment. With respect to the number employees, apparel manufacturers comprising 50∼99 employees were lied the most high complexity of product environment, while those comprising 100∼299 employees the most high demand/supply environment.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.28 no.4
• /
• pp.147-153
• /
• 2020

This study analyzed the outlook for aviation demand for the recovery of the aviation industry, focusing on airlines facing difficulties in management due to the Covid-19 crisis. Although the timing of the recovery in aviation demand is uncertain at the moment, this study is based on prior research related to Covid-19 and forecasts by aviation specialists, and analyzed by SWOT technique to a group of aviation experts to derive and suggest implications for the prospects of aviation demand. Looking at the implications based on the analysis results, first, customer trust to prevent infection should be considered a top priority for recovering aviation demand. Second, promote reasonable air price policy. Finally, it seeks to try various research and analysis techniques to predict long-term aviation demand to overcome Covid-19.

• Structural Engineering and Mechanics
• /
• v.28 no.4
• /
• pp.357-372
• /
• 2008

This study investigates effect of uncertainty in natural vibration period on the seismic demand. It is shown that since this uncertainty affects the acceleration and displacement responses differently, two ratios, one relating peak acceleration responses and the other relating the peak displacement responses, are not equal and both must be employed in evaluating and defining the critical seismic demand. The evaluation of the ratios is carried out using more than 200 strong ground motion records. The results suggest that the uncertainty in the natural vibration period impacts significantly the statistics of the ratios relating the peak responses. By using the statistics of the ratios, a procedure and sets of empirical equations are developed for estimating the probability consistent seismic demand for both linear and nonlinear systems.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.3
• /
• pp.789-795
• /
• 2014

In a demand response (DR) market run by independent system operators (ISOs), load aggregators are important market participants who aggregate small retail customers through various DR programs. A load aggregator can minimize the allocation cost by efficiently allocating its demand response resources (DRRs) considering retail customers' characteristics. However, the uncertain response behaviors of retail customers can influence the allocation strategy of its DRRs, increasing the economic risk of DRR allocation. This paper presents a risk-based DRR allocation method for the load aggregator that takes into account not only the physical characteristics of retail customers but also the risk due to the associated response uncertainties. In the paper, a conditional value-at-risk (CVaR) is applied to deal with the risk due to response uncertainties. Numerical results are presented to illustrate the effectiveness of the proposed method.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.7
• /
• pp.2589-2609
• /
• 2021

Segment routing (SR) is a highly implementable approach for traffic engineering (TE) with high flexibility, high scalability, and high stability, which can be established upon existing network infrastructure. Thus, when a network failure occurs, it can leverage the existing rerouting methods, such as rerouting based on Interior Gateway Protocol (IGP) and fast rerouting with loop-free alternates. To better exploit these features, we propose a high-performance and easy-to-deploy method SRUF (Segment Routing under Uncertain Failures). The method is inspired by the Value-at-Risk (VaR) theory in finance. Just as each investment risk is considered in financial investment, SRUF also considers each traffic distribution scheme's risk when forwarding traffic to achieve optimal traffic distribution. Specifically, SRUF takes into account that every link may fail and therefore has inherent robustness and high availability. Also, SRUF considers that a single link failure is a low-probability event; hence it can achieve high performance. We perform experiments on real topologies to validate the flexibility, high-availability, and load balancing of SRUF. The results show that when given an availability requirement, SRUF has greater load balancing performance under uncertain failures and that when given a demand requirement, SRUF can achieve higher availability.

• Asian Journal of Innovation and Policy
• /
• v.7 no.3
• /
• pp.581-605
• /
• 2018

In the soft drink industry, especially small and medium enterprises in Japan, there is a possibility of conversion from a labor-intensive industry to a capital-intensive. The demand for soft drinks may not be satisfied in the summer because the supply is too low to meet the demand. To address this situation, this paper proposes optimal investment that integrates demand uncertainty, based on real options approach (ROA) and seasonal autoregressive integrated moving average. Two alternative options are compared and evaluated. One is the Bermudan option: to employ additional workers to elevate efficiency in summer and laying off in winter, this attitude is repeated each year. The other is the American option: to replace equipment to increase machine ability throughout the year. Results in ROA show that the highest improvement is gained if the two options are in a symbiotic relationship. Soft drink producers should search for replacing equipment, using the employees repeatedly. A temporary decision is not equal to an infinite decision.

• The Journal of Korean Medicine
• /
• v.34 no.1
• /
• pp.69-79
• /
• 2013

Objectives: The aim of this survey was to investigate utilization, intended use, problems with and demand for medical devices by surveying members of the traditional Korean medical society. Methods: We distributed questionnaires to 13,957 traditional Korean medical doctors via e-mail, and received replies from 1,225. The questionnaire consisted of 4 multiple-choice questions for survey respondent information, 8 multiple-choice questions about the status of medical devices utilizing, and a short answer question about the demand for medical devices. Results: Use of medical devices in traditional Korean medical clinics is common. Diagnostic medical devices are mainly used to assess the patient's condition and to establish a close rapport with clients. In case of therapeutic medical devices, they are usually used for secondary treatment. Issues with traditional Korean medical devices currently in use were ineligibility for national health insurance, low reliability, uncertain validity, and high price. In development of traditional Korean medical equipment, the need for diagnostic medical devices was greater than for therapeutic, and the need for the recording and analysis of medical image data and visualization of medical information was great. Conclusions: There is growing demand for facilitating the development and commercialization of traditional Korean medical devices. To satisfy this demand, research on evaluation indicators that reflect functional and structural clinical information and how to clinically assess the indicators should proceed.

• Journal of Korean Institute of Industrial Engineers
• /
• v.2 no.1
• /
• pp.79-83
• /
• 1976

This paper deals with a computer simulation for the stochastic inventory system in which the decision rules are associated with the problem of forecasting uncertain demand, lead time, and amount of shortages. The model consists of mainly three parts; part I$\cdots$the model calculates the expected demand during lead time through the built-in subrou tine program for random number generator and the probability distribution of the demand, part II$\cdots$the model calculates all the possible expected shortages per lead time period, part III$\cdots$finally the model calculates all the possible total inventory cost over the simulation period. These total inventory costs are compared for searching the optimal inventory cost with the best ordering quantity and reorder point. An application example of the simulation program is given.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.8
• /
• pp.2840-2853
• /
• 2015

A major challenge in network service providers is to provide adequate resources in service level agreements based on forecasts of future demands. In this paper, we address the problem of capacity provisioning in a network subject to demand uncertainty such that a network coded multicast is applied as the data delivery mechanism with limited budget to purchase extra capacity. We address some particular type of uncertainty sets that obtain a tractable constrained capacity provisioning problem. For this reason, we first formulate a mathematical model for the problem under uncertain demand. Then, a robust optimization model is proposed for the problem to optimize the worst-case system performance. The robustness and effectiveness of the developed model are demonstrated by numerical results. The robust solution achieves more than 10% reduction and is better than the deterministic solution in the worst case.

• Management Science and Financial Engineering
• /
• v.18 no.2
• /
• pp.23-27
• /
• 2012

The problem of jointly determining a robust optimal bundle of price and order quantity for a retailer in a single-retailer, single supplier, single-product supply chain is considered. Demand is modeled as a decreasing power function of product price, and unit purchasing cost is modeled as a decreasing power function of order quantity and demand. Parameters defining the two power functions are uncertain but their possible values are characterized by ellipsoids. We extend a previous study in two ways; the purchasing cost function is generalized to take into account the economies of scale realized by higher product demand in addition to larger order quantity, and an exact transformation into an equivalent convex optimization program is developed instead of a geometric programming approximation scheme proposed in the previous study.