• Journal of the Society of Naval Architects of Korea
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• v.46 no.3
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• pp.362-371
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• 2009

Shipbuilding is a typical 'build to order' industry. It has a business model that generates revenues from building various ships and offshore products in accordance with owner's requirements at each production stage. Under uncertainty in shipping market, it is very essential for the shipbuilder to prepare the fast and competitive decision for product portfolio strategy in order to maximize contribution margin by exploiting production facilities and constraints. In this study, we introduce the unique decision supporting methodology for the optimal product portfolio sets based on Theory of Constraints(TOC). This methodology is established by adopting the concept of Drum Buffer Rope(DBR) in constraints planning and Throughput Accounting (TA) in management accounting of TOC. In addition, Decision Supporting System(DSS) is implemented. This DSS system provides a throughput estimator with reflecting the cost structure of shipbuilding industry and a resource simulator built on heuristic algorithms to operate major constraint-resources in shipyard such as dock, quay and pre-erection area etc. Several examples are presented to show that the proposed methodology and system can effectively support the strategic decision-making process of a global shipbuilding company.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.316-329
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• 2008

Recently the increased attention pays on the processing of multiple, relatively low quantity, high value-added products resulted in adoption of batch process in the chemical process industry such as pharmaceuticals, polymers, bio-chemicals and foods. As there are more possibilities of the improvement of operations in batch process than continuous processes, a lot of effort has been made to enhance the productivity and operability of batch processes. But the chemical process industry faces a range of uncertainties factors such as demands for products, prices of product, lead time for the supply of raw materials and in the production, and the distribution of product. And global competition has made it imperative for the process industries to manage their supply chains optimally. Supply chain management aims to integrate plants with their supplier and customers so that they can be managed as a single entity and coordinate all input/output flows (of materials, information) so that products are produced and distributed in the right quantities, to the right locations, and at the right time.The objective of this study is to solve the purchase, distribution, production planning and scheduling problem, which minimizes the total costs of production, inventory, and transportation under uncertainty. And development of SCM model in chemical industry including batch mode operations. Through that, the enterprise can respond to uncertainty. Also integrated process optimal planning and scheduling model for manufacturing supply chain. The result shows that, the advantage of supply chain integration are quality matters seen by customers and suppliers, order schedules, flexibility, cost reduction, and increase in sales and profits. Also, an integration of supply chain (production and distribution system) generates significant savings by trading off the costs associated with the whole, rather than minimizing supply chain costs separately.

• The Journal of Information Technology and Database
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• v.6 no.1
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• pp.15-25
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• 1999

We propose an extended relational data model which can represent the reliability of data. In this paper, the reliability of data is defined as the reliability of the source, from which the data originated. We represent the reliability of data at the level of attribute values, instead of tuples, then define the selection, product and join operators.

• Proceedings of the Technology Innovation Conference
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• 1992.12a
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• pp.119-155
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• 1992

Traditionally, the target of manufaturing technology strategy was derived in a efficiency, cost and productivity. So most activities of the manufacturing brought focus into the engineering technology, equipments and research and improvement of new products to maximize the efficiency. As a resell of this legacy, most of the activities of manufacturing has been executed on the method of quality improvement, development of new equipment to incense the efficiency and the research of materials for new products. Those trends, however overlook the operation management activities which is very important as a assets in competitive strategy. But the market enviornment of morden manufacturing companies faced to the uncertainty and complexity. So they need capability of competition which requires new concept of manufacturing technology strategy to grasp the competitive advantages. In this point of view, this paper deal with the empirical study in korean manufacturing technology strategy of the electic and electronic industry. For the empirical study, check list was made to survey the 98 manufacturing companies. The analysis procedures are as below. First, identify the manufacturing technology group an product structure group by each variable. Second manufacturing technology variables are segmented into product technology and vertical integration, suborder and infrastructure, to analyse the decision making pattern which derive the strategy groups. Third, by the fitness analysis between product structure group and manufacturing technology group, the economic results of a growth rate of sale and a profit rate of sale are tested. In this approach, fitness analysis between product structure group and manufacturing technology group show, as a whole, the no significant values in economic results of the company. But investigating the statistical values shows the trend that econmic result of the complany is somewhat higher when the degree of fitness of manufacturing technology strategy by product structure has high value. Concluding the remarks, the competitive advantages of company lies not in the efficiency of manufacturing systems but in the way of the structure and decision making pattern of the manufacturing system. And the cons i stoney between strategy target and manufacturing technology strategy, and the consistency of manufacturing technology strategy and product structure are the term of competitive advantages.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.244-246
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• 2006

Softwares in railway system are being used in the area of railway control system, directly associated to safety. Because the instinct characteristic of Software is uncertainty, Software development without safety insurance is very hazardous situation. In order to derive safety certification process in the railway system, certification and approval processes in the nuclear, aviation, and military area are studied. Software quality should be improved by two aspects : one is product aspect, another is process aspect. GS(Good Software) and ES(Excellent Software) certification can be exemplified in a product aspect approach. In those process certification, CMMI (Capability Maturity Model Integration) or SPICE (Software Process Improvement and Capability dEtermination : ISO/IEC15504) is being used as models for assessing process maturity of organization. Following the studies, safety management procedure in the railway system is suggested.

• Korean Management Science Review
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• v.33 no.4
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• pp.77-89
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• 2016

Due to recent proliferation of the mobile shopping channels, customers increasingly tend to purchase using online channel while experiencing physical products in offline shops. This phenomenon requires traditional offline retailers to consider integrating online channels. In this study, we propose strategic options for the traditional offline retailers regarding the online channel integration, and provide corresponding decision models to maximize the expected profits. We also investigate how the strategic options vary with the product characteristics, by categorizing the products based on inventory cost, demand uncertainty, and fitness to the online channels. By analyzing numerical examples we illustrate how the best online channel integration strategy should be differentiated depending on the product categories.

• Management Science and Financial Engineering
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• v.6 no.2
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• pp.1-28
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• 2000

Supply chain management issues faced by a manufacturing company are considered in this paper. The supply chain consists of a manufacturing company and its suppliers. The manufacturer produces multiple products with inputs (e.g., raw materials) from the suppliers, but each product needs a different mix of these inputs. The market demand for the products is uncertain. We develop a mathematical model and algorithm, which can help the manufacturer to solve its procurement decision problem: how much of raw material to order from which supplier. The model incorporates such factors as market demand uncertainty, product's input requirement, supplier's as well as manufacturer's capacity, plus other costs comparable with those in a typical newsboy problem. Numerical examples are presented to see the interacting effects among critical parameters and variables.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.4
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• pp.1-9
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• 2019

Most product structural components are assembled by various members and castings except casting products. In such cases, a particular structure is required to move and fix each component. In particular, the safety uncertainty of heavy product assemblies can be linked to large accidents. Thus, the safety design and evaluation of additional structures have become more important. In the field and factories, these additional structures are called handling structures, which are designed and manufactured. As the types of products produced become more diverse, the design and manufacture of a handling structure are also diversified. The results of each evaluation should be derived. We develop a logical design and evaluation method, which was previously designed based on empirical data, for the handling structure.

• Analytical Science and Technology
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• v.25 no.1
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• pp.83-90
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• 2012

The objective of the study was to estimate the measurement uncertainty associated with determination of creatinine (Cr) in urine samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Centrifuged urine samples (10 ${\mu}L$) were diluted with 390 ${\mu}L$ of distilled water. To 20 ${\mu}L$ aliquots of diluted urine samples, 30 ${\mu}L$ of internal standard solution (Cr-$d_3$, 5 ${\mu}g/mL$) and 10 ${\mu}L$ of acetonitrile were added and filtered. The samples (1 ${\mu}L$) were introduced into LC-MS/MS with no further pretreatment. Cr was separated on a multi-mode ODS column (Scherzo SM-C18, 75 ${\times}$ 2.0 mm I.D., 3 ${\mu}m$) and quantified by LC-MS/MS operating in MRM mode (Cr, m/z 114.0${\rightarrow}$ 86.0; Cr-$d_3$, m/z 117.0${\rightarrow}$ 89.1). The four factors that contribute uncertainty to the final result were extracted and evaluated. The principal factors of contribution to combined standard uncertainty were sample dilution, calibration curve and repeatability, while the preparation of standard solution was only a minor factor. Relative extended uncertainty of the measured concentration was 14.2% in a real urine sample.

• Nuclear Engineering and Technology
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• v.47 no.1
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• pp.11-25
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• 2015

The accident at Japan's Fukushima Daiichi nuclear power plant in March 2011, caused by an earthquake and a subsequent tsunami, resulted in a failure of the power systems that are needed to cool the reactors at the plant. The accident progression in the absence of heat removal systems caused Units 1-3 to undergo fuel melting. Containment pressurization and hydrogen explosions ultimately resulted in the escape of radioactivity from reactor containments into the atmosphere and ocean. Problems in containment venting operation, leakage from primary containment boundary to the reactor building, improper functioning of standby gas treatment system (SGTS), unmitigated hydrogen accumulation in the reactor building were identified as some of the reasons those added-up in the severity of the accident. The Fukushima accident not only initiated worldwide demand for installation of adequate control and mitigation measures to minimize the potential source term to the environment but also advocated assessment of the existing mitigation systems performance behavior under a wide range of postulated accident scenarios. The uncertainty in estimating the released fraction of the radionuclides due to the Fukushima accident also underlined the need for comprehensive understanding of fission product behavior as a function of the thermal hydraulic conditions and the type of gaseous, aqueous, and solid materials available for interaction, e.g., gas components, decontamination paint, aerosols, and water pools. In the light of the Fukushima accident, additional experimental needs identified for hydrogen and fission product issues need to be investigated in an integrated and optimized way. Additionally, as more and more passive safety systems, such as passive autocatalytic recombiners and filtered containment venting systems are being retrofitted in current reactors and also planned for future reactors, identified hydrogen and fission product issues will need to be coupled with the operation of passive safety systems in phenomena oriented and coupled effects experiments. In the present paper, potential hydrogen and fission product issues raised by the Fukushima accident are discussed. The discussion focuses on hydrogen and fission product behavior inside nuclear power plant containments under severe accident conditions. The relevant experimental investigations conducted in the technical scale containment THAI (thermal hydraulics, hydrogen, aerosols, and iodine) test facility (9.2 m high, 3.2 m in diameter, and $60m^3$ volume) are discussed in the light of the Fukushima accident.