• Journal of Korean Society for Quality Management
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• v.40 no.4
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• pp.441-452
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• 2012

Purpose: In this paper, we have considered a problem of newsvendor model in an environment of random yields in quality and customer balking behavior, in which only the mean and the variance of the demand are known. In practice, the distributional information of the demand is very limited and only the mean and variance are guessed by experience. In addition, due to the customers balking behavior occurring when the available inventory level decreases, the product's demand becomes a function of inventory level so that the classical newsvendor's optimal order quantity is no longer optimal. Methods: We have developed an optimal order quantity model that enables us to incorporate the random yield of a product and the customer balking information such as a threshold inventory level of balking and the corresponding probability of a sale during the balking. Results: We illustrated the concepts developed here through simple numerical examples and showed the robustness of our model in a various setting of parameters. Conclusion: This paper provides a useful analysis showing that our distribution-specific and distribution-free approach to the optimal order quantity in the newsboy model can act as an effective tools to match supply with demand for these product lines.

• Industrial Engineering and Management Systems
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• v.13 no.2
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• pp.129-147
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• 2014

This study proposes an optimal operational policy for a green supply chain (GSC) where a retailer pays an incentive for collection of used products from customers and determines the optimal order quantity of a single product under uncertainty in product demand. A manufacturer produces the optimal order quantity of product using recyclable parts with acceptable quality levels and covers a part of the retailer's incentive from the recycled parts. Here, two scenarios for the product demand are assumed as: the distribution of product demand is known, and only both mean and variance are known. This paper develops mathematical models to find how order quantity, collection incentive of used products and lower limit of quality level for recycling affect the expected profits of each member and the whole supply chain under both a decentralized GSC (DGSC) and an integrated GSC (IGSC). The analysis numerically compares the results under DGSC with those under IGSC for each scenario of product demand. Also, the effect of the quality of the recyclable parts on the optimal decisions is shown. Moreover, supply chain coordination to shift the optimal decisions of IGSC is discussed based on: I) profit ratio, II) Nash bargaining solution, and III) Combination of (I) and (II).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.1
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• pp.185-201
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• 2023

Grant-free random access (GFRA) can reduce the access delay and signaling cost, and satisfy the short transmission packet and strict delay constraints requirement in internet of things (IoT). IoT is a major trend in the future, which is characterized by the variety of applications and devices. However, most existing studies on GFRA only consider a single type of device and omit the effect of access delay. In this paper, we study GFRA in multicell massive multipleinput multiple-output (MIMO) systems where different types of devices with various configurations and requirements co-exist. By introducing the backoff mechanism, each device is randomly activated according to the backoff parameter, and active devices randomly select an orthogonal pilot sequence from a predefined pilot pool. An analytical approximation of the average spectral efficiency for each type of device is derived. Based on it, we obtain the optimal backoff parameter for each type of devices under their delay constraints. It is found that the optimal backoff parameters are closely related to the device number and delay constraint. In general, devices that have larger quantity should have more backoff time before they are allowed to access. However, as the delay constraint become stricter, the required backoff time reduces gradually, and the device with larger quantity may have less backoff time than that with smaller quantity when its delay constraint is extremely strict. When the pilot length is short, the effect of delay constraints mentioned above works more obviously.

• Journal of the Korean Graphic Arts Communication Society
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• v.22 no.2
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• pp.83-100
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• 2004

In this paper, the quantity of dot gain in off-set printing is estimated by using the method of UCR(under color removal) and GCR(gray component replacement) and the degree of dot gain is researched through measurement of dot coverage of each color patch at the output film that is variously applied to discretionary quantity of dot gain each line in screen in the printing for the process of color separation and at the offset printing. Also, the best appropriate quantity of dot gain treatment is examined by printing each line in screen for reproduction of colors.

• Journal of Korean Society for Quality Management
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• v.46 no.1
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• pp.11-26
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• 2018

Purpose: This study is to help the construction of smart factories of other manufacturing enterprises through IDIS 's case of smart factory construction. Methods: We introduce the four phases of implementing smart factory building by IDIS company, which produces a small quantity of multi-odd units. Results: Through the smart factory construction, the cost of product is reduced due to the improvement of total productivity such as office work, production work, and energy saving, and sales are enhanced by customized production, quality / delivery reliability improvement. Conclusion: We present the actual examples needed to build the manufacturer's smart factory.

• Journal of the Korea Safety Management & Science
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• v.19 no.3
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• pp.117-122
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• 2017

Companies are reluctant to disclose information because of trade secret and corporate identity For the same reasons, logistics companies do not want to operate in the form of a community In urban areas, the loading of vehicles is 100% as the quantity of goods transported is too much. In mountain areas, however, the load condition of the vehicle is not 100% because of the low quantity of goods transported Therefore, the transportation costs will increase as the cost of transport increase, the competitiveness of firms will also decline In this paper, we studied a simulation to measure driving time and volume of cargo according to the change of the quantity of goods transported in the mountain area According to the research results, we got a conclusion that the proposed method makes the operation time be less and the volume of cargo increase compared with the existing operation method.

• Journal of Family Resource Management and Policy Review
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• v.11 no.2
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• pp.85-93
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• 2007

The purpose of this study was to assess gender differences in the quantity and quality of leisure time. It uses time diary for a nationally representative sample of Koreans(10 years old over) collected in 2004 by KNSO. This time use surveys provide information about a primary activity and a secondary activity (that is simultaneous activity accompanying the primary activity). The results was that married women experience less of leisure time and more contaminated leisure time by a secondary activity(especially household labor) than married men. This research presents that men and women have different quantity and quality of leisure time, and gender discrepancies persist in the experience of leisure time.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.419-425
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• 2013

Recently AEC industry has required construction automation according to becoming large and complex. Thus BIM-based construction project is increased and used in whole fields of AEC industry. Quantity take-off and estimation fields are important factor for decision-making in conceptual and schematic design stages of construction projects. The purpose of this study improves reliability of the estimation through QTO based on Open BIM. Scope and method to apply QTO is to select conceptual design stage through LoD(Level of Detail) in AEC field and to extract information from BIM model through analysis of IFC structure. This study proceeds three step to make BIM model and check the model quality and calculate QTO. The methodology of QTO using IFC is to verify of result in this study and expects utilizing in design stage of construction projects. The result from this study is expected to decrease the risk factor and time of estimation in the project early phase through improving reliability of schematic estimation.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.7-11
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• 2011

Quantity take-off (QT) is one of the most important tasks for determining the total cost of a construction project, and it requires accuracy and reliability for the result. Accuracy and reliability in BIM-based QT are also required to assure the completeness of the result. However, there has been no basis to measure the completeness of the BIM-based QT result. As BIM is increasingly being adopted in the construction industry with a wide variety of purposes, it becomes more important to have a method to improve the completeness of BIM-based QT and criteria to measure it. This research focuses on the hypothesis that the completeness of BIM-based QT relies on the accuracy and reliability of BIM and the BIM-based QT process. As a basic research to determine the completeness of BIM-based QT, this research analyzes and derives factors that affect the completeness of BIM-based QT.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.5
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• pp.735-746
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• 2020

Recently, in Korea, various technology developments have been made to utilize 3D space and facility data such as unmanned aerial vehicles (UAV) and laser scanners with the goal of improving productivity at construction sites. However, the lack of related regulations for 3D laser scanner surveying has been a barrier to using the technology across the surveying industry. As a result, owners, contractors, and construction supervisors are reluctant to introduce and apply technology to the site. In this study, the guidelines (drafting and inspection work to be supervised by construction supervisors when constructing earthworks using laser scanners) was developed and presented so that the earth surveying and quantity calculation technology using a laser scanner could be applied and diffused in a construction site. Through the development of this guideline (proposal), it is judged that the supervision and inspection of earthworks quantity using a laser scanner will be activated in the field.