• Bulletin of the Korean Mathematical Society
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• v.60 no.2
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• pp.339-348
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• 2023

It is shown that every nilpotent-invariant module can be decomposed into a direct sum of a quasi-injective module and a square-free module that are relatively injective and orthogonal. This paper is also concerned with rings satisfying every cyclic right R-module is nilpotent-invariant. We prove that R ≅ R₁ × R₂, where R₁, R₂ are rings which satisfy R₁ is a semi-simple Artinian ring and R₂ is square-free as a right R₂-module and all idempotents of R₂ is central. The paper concludes with a structure theorem for cyclic nilpotent-invariant right R-modules. Such a module is shown to have isomorphic simple modules eR and fR, where e, f are orthogonal primitive idempotents such that eRf ≠ 0.

• International journal of advanced smart convergence
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• v.4 no.1
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• pp.145-153
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• 2015

Friction Stir Welding (FSW) is a solid state welding that could successfully weld the difficult-to-weldmaterials such as an aluminum alloy. In this welding process, the stirrer of the welding tool is one of the important factors for producing the perfect sound joint that indicates the higher joint strength. So, this report aims to apply the friction stir welding using various stirrer geometries to weld the AA6063-T1 aluminum alloy butt joint, investigates the mechanical properties of the joint and then compares the mechanical properties with the microstructure of the joint. An experiment was started by applying the friction stir welding process to weld a 6.3 mm thickness of AA6063-T1 aluminum alloy butt joint. A study of the stirrer geometries effect such as a cylindrical geometry, a cone geometry, a left screw geometry and a right screw geometry at a rotational speed of 2000 rpm and a welding speed of 50-200 mm/min was performed. The mechanical properties such as a tensile strength and a hardness of the joint were also investigated and compared with the microstructure of the joint. The results are as follows. A variation of FSW Stirrer shape directly affected the quality AA6063-T1 aluminum alloy butt joint. A cylindrical stirrer shape and a cone stirrer shape produced the void defect at the bottom part of the weld metal and initiated the failure of the joint when the joint was subjected to the load during the tensile test. Left and right screw stirrer shapes gave the sound joint with no void defect in the weld metal and affected to increase the joint strength that was higher than that of the aluminum base metal.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.4
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• pp.413-420
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• 2003

We can take 'Profit security', in the field Process improvement activity and man-power upgrade in the learning of organization activity or upgrading ability of each peoples. After Tayler System(Scientific Management in1911) and Ford System(Conveyor system in 1913), Toyota System(Ohno's TPS; Toyota Production System around 1980) which was developed by Toyota in Japan in the third productive revolution. This thesis study on the focus of 2 successful examples(P and S companies in Seong-Seo industrial complex Tae-Gu city) which introduce Toyota system can apply to VM(Visual Management), 3jeong(Right Products Right Quantity, Right Box and Right Position)5S(Seiri, Seiton, Seisoh Seiketsu, Sitsuke), JIT(Just In Time), KAIZEN(Improvement), KANBAN System(Logistic) and output of Factory. For examples P company obtained a lot of results(productivity increase 19%, Quality up 46%-36ppm, storage decrease 25% per year), S company obtained a lot of results(productivity increase 20%, Quality up 40%, storage decrease 33% per year, 2600 improvements in 2002. In conclusion Korean KANBAN system (modified Toyota System) is similar to exchange of work as Korean traditional system in agriculture as like dure 'PUMASHI' SANGBU-SANJO) that's autonomous management systems. In conclusion Korea KANBAN system needs apply to not only all the manufacturing industry but also the various fields of industry.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.8 no.2
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• pp.1-5
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• 2004

A multiplicative plane partition is a two-dimensional array of positive integers larger than 1 that are nonincreasing both from left to right and top to bottom and whose multiple is a given number n. For a natural number n, let $f_2(n)$ be the number of multiplicative plane partitions of n. In this paper, we prove $f_2(n)\;{\leq}\;n^2$ and a table of them up to $10^5$ is provided.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.710-713
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• 2008

LED Scanning Backlight Stereoscopic Display with Shutter Glasses is provided to realize stereoscopic image viewing even in a liquid crystal display. The eye shutter signal is alternately switched from the left eye to the right eye with 120Hz of LCD Vertical synchronization (V-sync).

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.3
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• pp.365-375
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• 1996

We consider an extension of the multiple choice linear knapsack problem and develop a fast algorithm of order $O(r_{max}n^2)$ by exploiting some new properties, where $r_{max}$ is the largest multiple choice number and n is the total number of variables. The proposed algorithm has convenient structures for the post-optimization in changes of the right-hand-side and multiple choice numbers. A numerical example is presented.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.4
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• pp.519-527
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• 1995

By finding some new properties, we develop an O($r_{max}n^2$) algorithm for the generalized multiple choice linear knapsack problem where $r_{max}$ is the largest multiple choice number and n is the total number of variables. The proposed algorithm can easily be embedded in a branch-and-bound procedure due to its convenient structure for the post-optimization in changes of the right-hand-side and multiple choice numbers. A numerical example is presented.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.4
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• pp.314-322
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• 2006

Despite its brilliant success, Six Sigma has suffered from two shortcomings, namely, the lack of a systematic method to identify the right projects in the "Define" stage and to sustain the improvement in the "Control" stage. The integration of Six Sigma and Business Process Management(BPM) seems to be a promising way to overcome the shortcomings of Six Sigma. This paper first reviews the existing efforts on this issue, and then proposes a framework for an effective integration of Six Sigma and BPM. The framework consists of five phases - DEFINE, EXECUTE, MONITOR, ANALYZE, and IMPROVE(DEMAI). A detailed description on the procedural model is also presented.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.1
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• pp.17-24
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• 2020

This study analyzes economic feasibility by looking at the case of wastewater reclamation and reuse system of Osan, the only place currently operated in Korea, exploiting wastewater uniquely reused as industrial water. Furthermore, this paper examines the problem in wastewater recycling and present the method to expand the potential of using reclaimed water. Method to activate the reuse of wastewater as industrial water. First, it is required to provide self-governing body and demander with diverse information on this project so that they correctly recognize the reuse of wastewater as industrial water. Second, law should be amended so that the water quality requirement of reused water can be given in the national level to supply industrial water depending on right standard. Third, financial support should be expanded in diverse parts so that more private investment advantageous to investor can be made, for instance, BTL, BTO.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.6
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• pp.13-20
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• 2011

Nowadays, digital-images are widely used at Web, industrial and medical applications. There have been many studies on online and Web copyright. But there are a few studies on industrial digital-image. In this paper, we propose the image encryption scheme for digital image in the industrial film. We implement and verify the proposed digital image encryption scheme for prevention of industrial secrets and intellectual property right outflow.