• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.477-477
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• 2000

A multifunctional sensor is designed to measure viscosity, cleanness, temperature and capacitance of engine oil to make a clear decision on its condition. The simple structure helps easy fabrication and low cost while measuring four parameters by one sensor. The operation is described theoretically and is supported by experimental data. A fuzzy based algorithm to fuse the four kinds of data from multi-functional sensor in order to make a decision on the best time to change the oil is proposed.

• Communications of the Korean Mathematical Society
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• v.38 no.2
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• pp.509-524
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• 2023

In this study, we characterize the structure of the multivariable mappings which are sextic in each component. Indeed, we unify the general system of multi-sextic functional equations defining a multi-sextic mapping to a single equation. We also establish the Hyers-Ulam and Găvruţa stability of multi-sextic mappings by a fixed point theorem in non-Archimedean normed spaces. Moreover, we generalize some known stability results in the setting of quasi-𝛽-normed spaces. Using a characterization result, we indicate an example for the case that a multi-sextic mapping is non-stable.

• The Journal of the Acoustical Society of Korea
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• v.20 no.5
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• pp.54-60
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• 2001

This paper investigates the equivalent circuit analysis method for the multi-functional device in mobile telephones, which works both as a buzzer and a vibrator in a single unit form. With a representative multi-functional device, we construct the corresponding equivalent circuits for the buzzer mode and the vibrator mode of the device, respectively, and analyze the performance of each of the modes. For proper construction of the circuit, we analyze the structure and operation mechanism of the device, and develop a computer simulation tool to simulate the behavior of the device. Validity of the analysis method is verified through comparison of the analysis results with experimental measurement results, which shows good agreement between the two sets of data.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.178-179
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• 2014

In this study, $Ni-W-Si_3N_4$ alloy composite coatings were prepared by pulse electrodeposition method using nickel sulfate bath with different contents of tungsten source, $Na_2WO_4.2H_2O$, and dispersed $Si_3N_4$ nano particles. The structure and microstructure ofcoatings was separately analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results indicated that nano $Si_3N_4$ and W content in alloy had remarkable effect on microstructure, microhardness and scratch resistant properties. Tungsten content in Ni-W and $Ni-W-Si_3N_4$ alloy ranged from 7 to 14 at.%. Scratch test results suggest that as compared to Ni-W only, $Ni-W-Si_3N_4$ prepared from Ni/W molar ratio of 1:1.5 dispersed with 20 g/L $Si_3N_4$ has shown the best result among different samples.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.629-639
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• 2014

This paper deals with an alternative multi-functional structures by using grid-stiffened composite structure with excellent bending stiffness and lightweight characteristics which is capable of easy embedding of electrical/electronic circuitry into structure. The enhancement of thermal conduction capability is made by the application of pitch-based carbon fiber. The lightweight radiation spot shielding technique is also proposed for multi-functional structures without conventional housing and the effectiveness of selective radiation shielding is validated through the proton irradiation test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.6
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• pp.526-534
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• 2011

The MFS (Mlti-Functional Structure) concept, which integrates the electronics, thermal control and structure into a single packaging system, has been developed and applied to reduce the volume and weight of the satellite. Therefore, this MFS can eliminate the bulky chassis/frames, cables and connectors of the electronic equipment. The main point of this traditional MFS is the replacement of the electrical chassis/frames with MCMs (Multi-Chip Modules) that require much costs and efforts for developing. This paper shows the new MFS concept that effectively saves the volume and weight. The structure including the thermal control and radiation shielding elements will be designed and manufactured as the rectangular grid-stiffened structure. The rectangular grid-stiffened structure is the modification of the iso-grid structure, and provides the enough spaces for putting the general PCBs without the chassis/frames.

• Journal of the Korean Institute of Educational Facilities
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• v.13 no.2
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• pp.34-41
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• 2006

A multi-sected campus can be explained as an university to be consisted of several campuses, which are physically separate, but are functionally interconnected. The basic structure of university campuses started with a single-nuclei structure of which the facilities were layed out around a single campus core, and it has been changed to multi-nuclei layout, where a single campus core was subdivided into several service cores due to increased service demands. The limitation on the expansion of campuses due to urbanization of surroundings leads to the physical separation of the campuses, and the development of information technology made it possible to connect physically-separate campuses to form the multi-sected campus. The three general characteristics of multi-sected campuses were found; 1) the need for programatic specialization of each individual campus, 2) the need for representative imageability for each campus, 3) necessity for physical connectivity between campuses and functional independency for each campus.

• Journal of the Korea Safety Management & Science
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• v.15 no.3
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• pp.133-141
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• 2013

As a work analysis technique, Work Domain Analysis (WDA) aims to identify the design knowledge structure of a work domain that human operators interact with through human-system interfaces. Abstraction hierarchy (AH) is a multi-level, hierarchical knowledge representation framework for modeling the functional structure of any kinds of systems. Thus, WDA based on AH aims to identify the functional knowledge structure of a work domain. AH has been used in a range of work domains and problems to model their functional knowledge structure and has proven its generality and usefulness. However, many of researchers and system designers have reported that it is never easy to understand the concepts underlying AH and use it effectively for WDA. This would be because WDA is a form of work analysis that is different from other types of work analysis techniques such as task analysis and AH has several unique characteristics that are differentiated from other types of function analysis techniques used in systems engineering. With this issue in mind, this paper introduces the concepts of WDA based on AH and offers a comprehensive list of references. Next, this paper proposes a set of principles for effectively applying AH for work domain analysis, which are developed based on the author's experiences, consultation with experts, and literature reviews.

• Polymer(Korea)
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• v.36 no.3
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• pp.315-320
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• 2012

Ultra violet (UV) curable pressure sensitive adhesives (PSA) were prepared by controlling both the structure of acryl copolymer and the functionality and content of multi-functional monomers. Acryl copolymer worked as the base polymer for giving the tackiness. Multi-functional monomers were used to vary the crosslinked structure and the degree of crosslink. Acryl copolymer showed the reduced peel strength after UV curing by decreasing the content of 2-ethylhexyl acrylate in the monomer composition. Both the peel strength of PSA and the content of residue found on silicon wafer decreased after UV curing by increasing the functionality of multi-functional monomers. UV curable PSA containing 20 phr six-functional monomer showed the higher peel strength before UV curing and the lower peel strength and the least residue on silicon wafer after UV curing.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.8
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• pp.689-696
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• 2001

Large-scale Multi-disciplinary Systems(LMS) such as transportation, aerospace, defense etc. are complex systems in which there are many subsystems, interfaces, functions and demanding performance requirements. Because many contractors participate in the development, it is necessary to apply methods of sharing common objectives and communicating design status effectively among all of the stakeholders. The processes and methods of systems engineering which includes system requirement analysis; functional analysis; architecting; system analysis; interface control; and system specification development provide a success-oriented disciplined approach to the project. This paper shows not only the methodology and the results of model-based systems engineering to Automated Guided Transit(AGT) system as one of LMS systems, but also propose the extension of the model-based tool to help manage a project by linking WBS (Work Breakdown Structure), work organization, and PBS (Product Breakdown Structure). In performing the model-based functional analysis, the focus was on the operation concept of an example rail system at the top-level and the propulsion/braking function, a key function of the modern automated rail system. The model-based behavior analysis approach that applies a discrete-event simulation method facilitates the system functional definition and the test and verification activities. The first application of computer-aided tool, RDD-100, in the railway industry demonstrates the capability to model product design knowledge and decisions concerning key issues such as the rationale for architecting the top-level system. The model-based product design knowledge will be essential in integrating the follow-on life-cycle phase activities. production through operation and support, over the life of the AGT system. Additionally, when a new generation train system is required, the reuse of the model-based database can increase the system design productivity and effectiveness significantly.