• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.11
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• pp.890-896
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• 2003

It is said that the goal of the design of good acoustical environment is at first the reduction of undesirable sounds. and in addition the introduction of desirable sounds by which our minds are soothed. The task of creating the desirable sounds leads to the realization of a comfortable acoustic environment and the design of soundscape. It may be an important starting point of soundscape design to select suitable sounds for the target spaces. because each space has a different surrounding condition and requires a special ambient sound. This paper aims to survey preference of the environmental sounds suitable for the public spaces in urban areas such as parks. bus terminals. 35 kinds of natural sounds are. rated by 26 pairs of adjectives. The results of psycho-acoustic experiments are as follows. 1. The proper adjectives for expressing the environmental sounds are classified into 6 groups of comfort, pleasure, fullness. variety, distinctness. and naturalness. 2. Bird singing. murmuring of a stream, artificial sounds. singing of insects and animals are the affirmative rank of preference. 3. Green musics consisted of music and natural sounds are preferred to the pure natural sounds. 4. Sound level relative to background noise causes various preferences to natural sounds in public spaces.

• The Journal of Society for e-Business Studies
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• v.1 no.1
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• pp.209-226
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• 1996

System Intergration (SI) has resently been conceived as one df the most important tools for enforciong and reinforcing the competitiveness of an enterprise. A major concern of SI lies in sharing many types of information, such as engineering, production, finance, marketing, and so on. Product Data Management (PDM) systems are mainly concerned with product- related information, and also support a large portion of the Commerce At Light Speed (CALS) straitegy. PDM systems receive a great amount df attention form industry, A variety of PDM solutions have been introduced for the last few years, and its market has expanded very fast with an annual growth of 30%. However, in general, it is not an easy task to choose a right PDM solution for a particular company. A major purpose of this paper is to provide essential factors in evaluating PDM systems. While developing the factors. we consider the expected future trend of PDM technologies and three types of PDM-based intergration (frontward, rearward, and sideward integrations). We Propose to carry out the evaluation process in two fold. An overall evaluation is performed first to narrow down many alternatives into a few candidate systems, and then a detailed technical evaluation step follows to determine the final solution. A number of influencing factors are categorized and described in each of these steps.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.2
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• pp.97-104
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• 2015

Compared with a strong axial rigidity due to large intial tension, cable has a weak laterally flexural rigidity. A variety of dynamic loads such as traffic loads and wind loads etc. cause the cables to vibrate significantly and affect the mechanical properties and the performance of cables. Therefore, vibration reduction design is an urgent task to control the vibration of cable-supported bridges. Because a various kind of dampers have shown to reduce the amplitude and duration time of vibration of cable from measured date in field test, damper can be considered that it is effective device significantly to reduce the amplitude and duration time in vibration of cable. Vibration characteristics of cable can change according to manufacturing method and type of established form, and damper has been designed according to distribution of natural frequencies and vibration modes. In this study, numerical analysis is used to show the reduction effects of vibrations and present the design of damper for vibration reduction of cable.

• Journal of Information Processing Systems
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• v.6 no.3
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• pp.307-322
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• 2010

Traffic classification is an essential task for network management. Many researchers have paid attention to initial sub-flow features based classifiers for traffic classification. However, the existing classifiers cannot classify traffic effectively in mobile IP networks. The classifiers depend on initial sub-flows, but they cannot always capture the sub-flows at a point of attachment for a variety of elements because of seamless mobility. Thus the ideal classifier should be capable of traffic classification based on not only initial sub-flows but also various types of sub-flows. In this paper, we propose a classifiable sub-flow selection method to realize the ideal classifier. The experimental results are so far promising for this research direction, even though they are derived from a reduced set of general applications and under relatively simplifying assumptions. Altogether, the significant contribution is indicating the feasibility of the ideal classifier by selecting not only initial sub-flows but also transition sub-flows.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.3
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• pp.40-48
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• 2009

In this article, scheduling of a casting sequence is studied in a casting foundry which must deliver products according to the Just-in-time(JIT) production policy of a customer. When a foundry manufactures a variety of casts with an identical alloy simultaneously, it frequently faces the task of production scheduling. An optimal casting schedule should be emphasized in order to maximize the production rate and raw material efficiency under the constraints of limited resources; melting furnaces and operation time for a casting machine. To solve this practical problem-fulfilling the objectives of casting the assigned mixed orders for the highest raw material efficiency in a way specified by the customer's JIT schedule, we implement simple integer programming. A simulation to solve a real production problem in a typical casting plant proves that the proposed method provides a feasible solution with a high accuracy for a complex, multi-variable and multi-constraint optimization problem. Employing this simple methodology, a casting foundry having an automated casting machine can produce a mixed order of casts with a maximum furnace utilization within the due date, and provide them according to their customer's JIT inventory policy.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.7
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• pp.720-725
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• 2008

This paper proposes a system architecture for USN with a service robot to provide more active assisted living services for elderly persons by monitoring their mental and physical well-being with USN environments at home, hospital, or silver town. Sensors embedded in USN are used to detect preventive measures for chronic disease. Logged data are transferred to main controller of a service robot via wireless channel in which the analysis of data is performed. For the purpose of handling emergency situations, it needs real-time processing on gathering variety sensor data, routing algorithms for sensor nodes to a moving sink node and processing of logged data. This paper realized multi-hop sensor network to detect user movements with biometric data transmission and performed algorithms on Xenomai, a real-time embedded Linux. To leverage active sensing, a mobile robot is used of which task was implemented with a priority to process urgent data came from the sink-node. This software architecture is anticipated to integrate sensing, communication and computing with real-time manner. In order to verify the usefulness of a proposed system, the performance of data transferring and processing on a real-time OS with non real-time OS is also evaluated.

• Journal of IKEEE
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• v.5 no.2 s.9
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• pp.164-173
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• 2001

In this paper, we have designed and implemented a new hard embedded real-time system to satisfy hard real-time constraints in moving independently. Real-time kernel should be small size, fast and predictable. Because of the great variety of demands on real time scheduling, a real time kernel should also include a flexible and re-programmable task scheduling discipline. In this paper, we present that real-time applications should be split into small and simple parts with hard real-time constraints. To satisfy these properties, we designed real-time kernel and general kernel, that have their different properties. In real-time tasks, interrupt processing should be run. In general kernel, non real time tasks or general tasks are run. The efficiency of the proposed hard embedded real-time system is shown by comparison results for performance of the proposal real time kernel with both RT-Linux and QNX.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.1 no.1
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• pp.13-23
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• 2001

Most current machine vision systems for industrial inspection were developed with one specific task in mind. Hence, these systems are inflexible in the sense that they cannot easily be adapted to other applications. In this paper, a general vision system framework has been developed that can be easily adapted to a variety of industrial web inspection problems. The objective of this system is to automatically locate and identify \\\"defects\\\" on the surface of the material being inspected. This framework is designed to be robust, to be flexible, and to be as computationally simple as possible. To assure robustness this framework employs a combined strategy of top-down and bottom-up control, hierarchical defect models, and uncertain reasoning methods. To make this framework flexible, a modular Blackboard framework is employed. To minimize computational complexity the system incorporates a simple multi-thresholding segmentation scheme, a fuzzy logic focus of attention mechanism for scene analysis operations, and a partitioning if knowledge that allows concurrent parallel processing during recognition.cognition.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.370-375
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• 2004

The management of daily work report is very important due to the variety of work trade and activities. Although various project management systems have been developed to effectively deal with various task in site, they are not in practical use due to the non-coorperative attitude of sub-contractors. This is the reason the system are not developed in the focus of sub-contractors, but main contractors and the detail information about daily work report is omitted or lost in the collection process by contractors. Therefore the purpose of this study was to propose the Web-based coordination system for daily work report between contractor and sub-contractors

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.523-528
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• 2001

There are many difficult problems in analyzing the flow characteristics in a high voltage circuit breaker such as shock wave and complex geometries, which may be either static or in relative motion. Although a variety of mesh generation techniques are now available, the generation of meshes around complicated, multicomponent geometries like a gas circuit breaker is still a tedious and difficult task for the computational fluid dynamics. This paper presents the computational method for analyzing the compressible flow fields in a high voltage gas circuit breaker using the Cartesian cut-cell method based on the CFD-CAD integration, which can achieve the accurate representation of the geometry designed by a CAD tools. The technique is frequently satisfied, and it will be almost universally so in the future, as the CFD-CAD traffic increases.