• Journal of the Korean institute of surface engineering
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• v.51 no.6
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• pp.421-429
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• 2018

In this study, various electrochemical experiments were carried out to compare the corrosion characteristics of AA5052-O, AA5083-H321 and AA6061-T6 in seawater. The electrochemical impedance and potentiostatic polarization measurements showed that the corrosion resistance is decreased in the order of AA5052-O, AA5083-H321 and AA6061-T6, with AA5052-O being the highest resistant. This is closely associated with the property of passive film formed on three tested Al alloys. Based on the slope of Mott-Schottky plots of an n-type semiconductor, the density of oxygen vacancies in the passive film formed on the alloys was determined. This revealed that the defect density is increased in the order of AA5052-O, AA5083-H321 and AA6061-T6. Considering these facts, it is implied that the addition of Mg, Si, and Cu to the Al alloys can degrade the passivity, which is characterized by a passive film structure containing more defect sites, contributing to the decrease in corrosion resistance in seawater.

• The Journal of Information Systems
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• v.17 no.4
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• pp.321-340
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• 2008

Collaborative planning, forecasting and replenishment (CPFR) is the most recent successful management initiative that provides supply chain collaboration. By adopting CPFR, companies can dramatically improve the effectiveness of supply chain. The CPFR process has three major sub-processes; planning, forecasting and replenishment, which are formed by a number of steps. Despite the existence of a detailed and comprehensive process model, which is published by the Voluntary Interindustry Commerce Standards Association, in practice CPFR can take a number of different forms. Therefore, this research suggests that business process management system (BPMS) can be utilized as a base system on which a CPFR is consistently constructed and implemented, regardless of a number of its possible forms. We illustrate how a CPFR protype is implemented by using a BPMS and then describe how the prototype is agilely extended to adopt a variety of changes of CPFR collaboration process.

• Journal of the Korean Mathematical Society
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• v.37 no.2
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• pp.321-337
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• 2000

• The Korean Journal of Air & Space Law and Policy
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• v.11
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• pp.321-327
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• 1999

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.321-321
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• 2009

This paper presents quasi-zero-stiffness (QZS) characteristic of a passive isolator using flexures under compression force. The passive isolator consists of a positive stiffness element (a vertical coil spring) and a negative stiffness element (flexures under compression force), and their proper combination of the positive and negative stiffness elements can produce both substantial static and zero dynamic stiffness, so called QZS. Firstly, a nonlinear dimensionless expression of a flexure under compression force is derived. A dynamic model of the passive isolator is developed and numerical simulations of its time and frequency response are performed. Then, undesirable nonlinear vibration is quantified using a period doubling bifurcation diagram and a Poincare's map of the isolator under forced excitation. Finally, experiments are performed to validate the QZS characteristic of the passive isolator.

• Korean Journal of Computational Design and Engineering
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• v.18 no.5
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• pp.321-328
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• 2013

A method of designing a manufacturing shape of ship plate parts considering welding deformation is introduced. In this paper, the design shape of a bracket is deformed not by a thermoelastic method but by a pure geometric method. Deformation quantities are estimated based on data captured in the field and then a manufacturing design shape is obtained by deforming an original design shape by a geometric deformation method. The proposed method has been implemented and tested in the shipyard.

• Communications for Statistical Applications and Methods
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• v.22 no.4
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• pp.321-331
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• 2015

The K-means clustering algorithm is a popular and widely used method for clustering. For covariance matrices, we consider a geodesic clustering algorithm based on the K-means clustering framework in consideration of symmetric positive definite matrices as a Riemannian (non-Euclidean) manifold. This paper considers a geodesic clustering algorithm for data consisting of symmetric positive definite (SPD) matrices, utilizing the Riemannian geometric structure for SPD matrices and the idea of a K-means clustering algorithm. A K-means clustering algorithm is divided into two main steps for which we need a dissimilarity measure between two matrix data points and a way of computing centroids for observations in clusters. In order to use the Riemannian structure, we adopt the geodesic distance and the intrinsic mean for symmetric positive definite matrices. We demonstrate our proposed method through simulations as well as application to real financial data.

• Korean Journal of Veterinary Service
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• v.36 no.4
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• pp.321-325
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• 2013

A mass of the adrenal gland was observed during a routine necropsy of a female 23-year-old Asian Water Buffalo (Bubalus bubalis) at Seoul Zoo in Gyeonggi Province, Korea. The animal showed no clinical signs but the necropsy examination revealed hydropericardium, ascites, hydrothorax and edema of the intestinal wall, lung and adrenal gland. Histopathologically, the neoplastic cells of the right adrenal gland were arranged in lobules supported by a fine fibrovascular stroma. The neoplastic cells had round hyperchromatic nuclei and granular eosinophilic to basophilic cytoplasm. Immunohistochemically, tumor cells were positive for chromogranin A and S-100 and negative for vimentin, synaptophysin and cytokeratin. Based on the above findings, this case was diagnosed as a pheochromocytoma. To the best of our knowledge, this is the first report of a pheochromocytoma in an Asian Water Buffalo (Bubalus bubalis).

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.6
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• pp.321-328
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• 2018

This paper presents an automatic target tracking flight system using a PID controller based on velocity command of a multirotor UAV. The automatic flight system includes marker based onboard target detection and an automatic velocity command generation replacing manual controller. A quad-rotor UAV is equipped with a camera and an image processing computer to detect the marker in real time and to estimate the relative distance from the target. The marker tracking system consists of PID controller and generates velocity command based on the relative distance. The generated velocity command is used as the input of the UAV's original flight controller. The operation of the proposed system was verified through actual flight tests using a marker on top of a moving vehicle and tracks it to successfully demonstrate its capability using a quad-rotor UAV.

• Journal of Navigation and Port Research
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• v.36 no.4
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• pp.321-327
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• 2012

Logistics in a supply chain network has become an important operational strategy in a competitive market. A number of internal and external risks involved in the logistics operations in a company tend to create problems in fulfilling customer orders. This research presents how ERM (enterprise risk management) can be used to identify, assess, and control logistics risks. An electronic company's logistics activities were used as an industry case to demonstrate a way to identify and assess risks surrounding global logistics function. This paper has further presented action plans to mitigate the impact of the risks that occur.