• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.3
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• pp.35-43
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• 2012

Medium size rotorcraft consist of approximately 5,000 key components. The components must satisfy the target weight and performance requirement through optimization. Therefore a rotorcraft component has approximately 100 times higher unit cost for mass production than the equivalent of an automobile's, along with huge development cost. Configuration management consists of four main parts : configuration identification, configuration control, configuration audit, and data management. In development programme, configuration management is one of the methods to save development cost, and setting a well-structured configuration management system according to the Military Standard is an important factor in success of the programme. The paper proposes a configuration management system suitable for development of various multi-use components development and presents that the configuration management was performed successfully during dual-use component development programme using the established system.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.398-403
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• 2000

The design of multi-stage gear drives is a time-consuming process that includes additional design problems, which are not considered in the design of single-stage gear drives. In the previous research works, the authors have proposed a new algorithm to design multi-stage gear drives at the preliminary design phase. The proposed design algorithm automates the design process by integrating the dimensional design and the configuration design process. In the configuration design process, the positions of gears and shafts are determined by minimizing the geometrical volume (size) of a gearbox. However, various types of spatial constraints should be satisfied in practical design situation. To locate input and output shaft in specified positions is the typical example of such problems. In this paper, the authors show the formulations of spatial constraints applied to the design of four-stage gear drives. The design solution shows considerably good results, and the design system is confirmed to be readily applicable to practical design situation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.464-469
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• 1999

Recently, the need for designing multi-stage gear drive has been increased as the hear drives are used more in the applications with high-speed and small volume. The design of multi-stage gear drives includes not only dimensional design but also configuration design of various machine elements. Until now, however, the researches on the design of gear drives are mainly focused on the single-stage gear drives and the design practices for multi-stage gear drives, especially in configuration design activity, mainly depend on the experiences and 'sense' of the designer by trial and error. We propose a design algorithm to automate the dimension design and the configuration design of multi-stage gear drives. The design process consists of four steps. The number of stage should be determined in the first step. In second step, the gear ratios of each reduction stage are determined using random search, and the ratios are basic input for the dimension design of gears, which is performed by the exhaustive search in third step. The designs of gears are guaranteed by the pitting resistance and bending strength rating practices by AGMA rating formulas. In configuration design, the positions of gears are determined to minimize the volume of gearbox using simulated annealing algorithm. The effectiveness of the algorithm is assured by the design example of a 4-stage gear drive.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.3
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• pp.385-392
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• 2009

This study aims to methodology a system which is able to monitor and configuration management of long span bridge in real time using multi GPS. Through setting up many GPS at the important points of long span bridge and measuring displacement in real time, over all 3D configuration of bridge could be analyzed. Behavior analyzing system developed in this study is able to digitize and visualize the overall and points displacement of bridge and deal with events actively. Also it is able to calculate statistical data related to analyze behavior through the constricting database of measuring data.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.5
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• pp.161-166
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• 1998

As a part of the configuration design expert system of machine tools, inference mechanisms are constructed in this paper. In addition to procedural inference, the method of multivariable inference is considered as an efficient approach to deal with the cases of highly coupled condition. We propose a generalized multi-variable inference procedure. The procedure is applied to the type selection module of the configuration design expert system of machine tools in order to demonstrate the efficiency and validity.

• Korean Journal of Computational Design and Engineering
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• v.20 no.4
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• pp.337-347
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• 2015

This paper presents a dynamic association and natural interaction method for multi-displays composed of smart devices. Users can intuitively associate relations among smart devices by shake gestures, flexibly modify the layout of the display by tilt gestures, and naturally interact with the multi-display by multi-touch interactions. First of all, users shake their smart devices to create and bind a group for a multi-display with a matrix configuration in an ad-hoc and collaborative situation. After the creation of the group, if needed, their display layout can be flexibly changed by tilt gestures that move the tilted device to the nearest vacant cell in the matrix configuration. During the tilt gestures, the system automatically modifies the relation, view, and configuration of the multi-display. Finally, users can interact with the multi-display through multi-touch interactions just as they interact with a single large display. Furthermore, depending on the context or role, synchronous or asynchronous mode is available to them for providing a split view or another UI. We will show the effectiveness and advantages of the proposed approach by demonstrating implementation results and evaluating the method by the usability study.

• Journal of the Korea Society of Computer and Information
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• v.24 no.3
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• pp.65-75
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• 2019

Non-Functional Requirements (NFR) play a crucial role during the software development process. Currently, NFRs are considered more important than Functional Requirements and can determine the success of a software system. NFRs can be very complicated to understand due to their subjective manner and especially their conflicting nature. Self-adaptive systems (SAS) are operating in dynamically changing environment. Furthermore, the configuration of the SAS systems is dynamically changing according to the current systems context. This means that the configuration that manages the trade-off between NFRs in this context may not be suitable in another. This is because the NFRs satisfaction is based on a per-context basis. Therefore, one context configuration to satisfy one NFR may produce a conflict with another NFR. Furthermore, current approaches managing Non-Functional Requirements trade-off stops managing them during the system runtime which of concern. To solve this, we propose fragmentizing the NFRs and their alternative solutions in form of Multi-entity Bayesian network fragments. Consequently, when changes occur, our system creates a situation specific Bayesian network to measure the impact of the system's conditions and environmental changes on the NFRs satisfaction. Moreover, it dynamically decides which alternative solution is suitable for the current situation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.618-622
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• 2004

The vibration test system of SITC(Satellite Integration and Test Center) at KARI(Korea Aerospace Research Institute) has been used successfully for the environmental tests of a majority of korean space programs, such as KOMPSAT, Koreasat KITSAT, STSAT and KSR program since 1996. To meet the recent needs of large size test facility available for the vibrational tests of the huge launch vehicles and tole-communication satellites which will be developed in the near future, KARI undertook to construct the large size multi-electromagnetic shaking system with 3 $\times$ 3m head expander system. The new system will consist of three electromagnetic shakers which has 160 kN thrust force individually, and be able te sustain up to 8 tons test load and 300 kNm overturing moment. And to avoid the tremendous cost and effort to furnish the seismic block with large size and weight, it will adopt a Lin-E-Air type configuration with which the seismic block is less severe than a Solid-Truninon type. In addition, to fulfill the strong requirement of high overturning moment the additional guidance system including a central bearing system on a central support and several pad bearings around the head expander body is now considered. This paper describes the configuration and the design parameters of the multi-shaking system which is under development by KARI's engineers.

• Smart Structures and Systems
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• v.30 no.6
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• pp.583-599
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• 2022

In this paper, a multi-objective wireless sensor network configuration optimization method is proposed. The proposed method aims to determine the optimal information and lifespan wireless sensor network for structural health monitoring of large-scale infrastructures. In particular, cluster-based wireless sensor networks with multi-type of sensors are considered. To optimize the lifetime of the wireless sensor network, a cluster-based network optimization algorithm that optimizes the arrangement of cluster heads and base station is developed. On the other hand, based on the Bayesian inference, the uncertainty of the estimated parameters can be quantified. The coefficient of variance of the estimated parameters can be obtained, which is utilized as a holistic measure to evaluate the estimation accuracy of sensor configurations with multi-type of sensors. The proposed method provides the optimal wireless sensor network configuration that satisfies the required estimation accuracy with the longest lifetime. The proposed method is illustrated by designing the optimal wireless sensor network configuration of a cable-stayed bridge and a space truss.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.3
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• pp.285-297
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• 2016

In this paper, a centralized mmWave-based multi-spot beam cellular system architecture having such a base station equipped with a plurality of beam-forming antennas, multi-layered dynamic cell configuration method as one of key concepts of this system operation and a mobility management method based on it are introduced. To estimate the performance of new system, system simulation was performed under the ideal environment without blockage. These results show the possibility that system capacity can be dramatically increased and mobility performance similar to the existing cellular system may be achieved.