• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.2
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• pp.175-182
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• 1993

The probabilistic order level inventory model is developed when a supplier allows some credit period T for settling the accounts for purchase quantity. The credit period T is known constant. Mathematical models are derived for both the cases i) T'.leq. T and ii) T'>T. Expressions are derived for average expected total cost of the system, the optimum cycle time and for obtaining optimum order level S = S$_{0}$ in each case. The exmaples are given to illustrate the model.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.6
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• pp.447-460
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• 2012

In this study, the shutdown system of the fuel gas supply system is designed based on the Safety Integrity Level of IEC 61508 and IEC 61511. First of all, the individual risk($10^{-4}$/year) and the risk matrix which are the risk acceptance criteria are set up for the qualitative risk assessment such as the HAZOP study. The natural gas leakage at the gas supply pipe is identified as the highest risk among the hazards identified through the HAZOP study and as a safety instrumented function the shutdown function for leakage was defined. SIL 2 and PFD($2.5{\cdot}10^{-3}$) for the shutdown function are determined by the layer of protection analysis(LOPA). The shutdown system(SIS) carrying out the shutdown function(SIF) is verified and designed according to qualitative and quantitative requirements of IEC 61508 and IEC 61511. As a result of SIL verification and SIS conceptual design, the shutdown system is composed of two gas detectors voted 1oo2, one programmable logic solver, and two shutdown valve voted 1oo2.

• Tribology and Lubricants
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• v.26 no.2
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• pp.129-135
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• 2010

Geckos have a unique ability to cling to ceilings and walls utilizing dry adhesion. Their foot pads are covered by a large number of small hairs (setae) that contain many branches per seta with a lower level of spatulae. Their fibrillar structure is the primary source of high adhesion. In this study, we construct the adhesion design database for biomimetic adhesive system. A simple idealized fibrillar structure consisting of single array of beams is modeled. The fibers are assumed as oriented cylindrical cantilever beams with spherical tip. We consider three necessary conditions; buckling, fracture and sticking of fiber structure, which constrain the allowed geometry. The adhesion analysis is performed for the attachment system in contact with rough surfaces with different s values for different main design variables-fiber radius, aspect ratio and material elastic modulus and so on. The developed adhesion design databases are useful for understanding biological systems and for guiding of fabrication of the biomimetic attachment system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.1
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• pp.149-158
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• 1987

This paper describes the SEAS which is a 2-dimensional graphic editor for schematic circuit and IC mask layout. This system runs on general purpose computer and Tektronix 4110 series graphic terminal. With this system, user can edit schematic circuits and/or IC mask layout with 2 level hierarchy. This system supports more than 20 kinds of built-in symbol, user definable internal symbols, 60 macros, 16 function keys, 4 level on-screen menu operation and edit-in-place of cell in main drawing. And it provides editing functions such as reflection, rotation, move and copy of one or a group of elements, and modification of polygona geometry etc. To improve the excution speed, we used local memory of graphic terminal. For the portability of the program, the system is written in FORTRAN 77 programming language.

• Communications for Statistical Applications and Methods
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• v.2 no.2
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• pp.358-365
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• 1995

This paper presents another system of multi-level skip-lot sampling plan, which can directly retum to normal inspection from any skpping inspection level when a sudden shift for the worse in the process mean occurs. All the other properties of the proposed sampling plan are similar to those of the Choi's(1993) plan. The formula of the poerating characteristic function for the proposed n-level skip-lot sampling plan is derived. Sone poerating characteristic properties for the proposed plan are graphically compared with those of the Choi's plan.

• KIEE International Transactions on Power Engineering
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• v.4A no.2
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• pp.84-90
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• 2004

This paper presents a new method for choosing the best line for transmission system expansion planning considering the highest reliability level of the transmission system. Conventional methodologies for transmission system expansion planning have been mainly focused on economics, which is the minimization of construction costs. However, quantitative evaluation of transmission system reliability is important because successful operation and planning of an electric power system under the deregulated electricity market depends on transmission system reliability management. Therefore, it is expected that the development of methodology for choosing the best lines considering the highest transmission system reliability level while taking into account uncertainties of transmission system equipment is useful for the future. The characteristics and effectiveness of the proposed methodology are illustrated by the case study using a MRBTS.

• Journal of the Korean Society of Systems Engineering
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• v.13 no.2
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• pp.57-64
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• 2017

A new paradigm based on distributed manufacturing services is emerging. This paradigm shift can be realized by smart functions and smart technologies such as Cyber Physical System (CPS), Artificial Intelligence (AI), and Cloud Computing. Most architectures define stack levels from Level 0 (equipment) to Level 4 (business area) and specify the services to be provided between them. Because of their a rough technical specification, there is a limitation on how to actually utilize a technology to actually implement a smart factory service with this architecture. In this paper, we propose a smart factory architecture that can be utilized directly from the perspective of a smart service system by making the use of System Engineering Process and System Modeling Language (SysML).

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.255-260
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• 2013

Nowadays, the intelligent education system has been studied using the self-directed learning ability. It can connect to the online virtual university and it is based on web technology that can be accessed anywhere anyplace. In order to implement the intelligent tutoring system, the student's weak and strong subjects must be first determined in real time, it proposed level learning capabilities and security algorithms in this paper. Moreover, in this paper, to implement the intelligent education tutoring system it proposed qr code and student level learning simulation.

• Journal of the Korean Home Economics Association
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• v.33 no.1
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• pp.99-110
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• 1995

The purpose of this study was to provide basic material of positive effects on moral development through educational intervention between parent and chile reciprocal. The major findings were as follows: (1)Child's moral development level was a significant difference according to the level of socialization patterns. (2) Predictability of subvariables of socialization patterns revealed an order of mode of social control, role system and communication system. (3) Therer was a significant difference between stage 2 and the other of stages in socialization patterns. (4) There was a significant difference between stage 2 and stage P in role system. (5) There was no difference between stage 2 and the other of stages in communication system, mode of social control, IQ, and S.E.S.

• KIEAE Journal
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• v.9 no.2
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• pp.99-106
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• 2009

The noise in apartment buildings are major factor that determine the quality of indoor noise environment. Particularly, the noise from children's running footsteps and plumbing noise have caused the residents who live in decrepit apartment houses to uncomfortable environment. And as time go by, sound performance are getting worse according to the aging of the facilities. So this study deals with the plans to improve the sound performance of decrepit apartment house. To compare the noise reduction, we measured the heavy-weight impact sound level and plumbing noise level before and after changes the measurement conditions. As the results of measurements, the heavy-weight impact sound level were decreased when stiffness reinforcement were installed on slab. Especially the sound level were decreased 2.1-7.6dB in 50-80Hz of low frequency range. Instead of PVC pipe system, cast iron pipe and triple elbow drain pipe systems were installed. Noise level were decreased 15dB(A) in 250Hz. Noise level of pipe system's on the slab is less than under slab one. On the contrary water saving stool showed increasing the noise level.