• The Journal of the Acoustical Society of Korea
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• v.16 no.1E
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• pp.15-23
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• 1997

Zero-Crossings with Peak Amplitudes(ZCPA) model motivated by human auditory periphery was proposed to extract reliable features speech signals even in noisy environments for robust speech recognition. In this paper, some practical considerations for digital hardware implementations of the ZCPA model are addressed and evaluated for recognition of speech corrupted by several real world noises as well as white Gaussian noise. Infinite impulse response(IIR) filters which constitute the cochliar filterbank of the ZCPA are replaced by hamming bandpass filters of which frequency responses are less similar to biological neural tuning curves. Experimental results demonstrate that the detailed frequency response of the cochlear filters are not critical to performance. Also, the sensitivity of the model output to the variations in microphone gain is investigated, and results in good reliability of the ZCPA model.

• The Journal of the Acoustical Society of Korea
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• v.27 no.1E
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• pp.30-34
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• 2008

An improvement to the existing blind signal separation (BSS) method has been made in this paper. The proposed method models the inherent signal dependency observed in acoustic object to separate the real-world convolutive sound mixtures. The frequency domain approach requires solving the well known permutation problem, and the problem had been successfully solved by a vector representation of the sources whose multidimensional joint densities have a certain amount of dependency expressed by non-spherical distributions. Especially for speech signals, we observe strong dependencies across neighboring frequency bins and the decrease of those dependencies as the bins become far apart. The non-spherical joint density model proposed in this paper reflects this property of real-world speech signals. Experimental results show the improved performances over the spherical joint density representations.

• Journal of Auto-vehicle Safety Association
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• v.9 no.4
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• pp.48-54
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• 2017

This paper presents the motorcycle inspection standards development on the vehicle identification, engine and transmission, tyres and wheels, steering and suspension, and brake system. 187 real-world motorcycles are visually and mechanically inspected according to the developed inspection standards. The non-compliance rate of the vehicle identification is 20.3% and main causes are insecure, damaged, and not clearly visible number plate. The non-compliance rate of the brake system is 15.5% and main cause is failing to meet the brake performance requirements. The motorcycle inspections standards are improved reflecting 187 cases of real-world motorcycle inspection results.

• Journal of Auto-vehicle Safety Association
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• v.9 no.4
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• pp.55-60
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• 2017

This paper presents the motorcycle inspection standards of electrical system, frame & body, lights and speedometers. 187 real-world motorcycles are visually and mechanically inspected according to the developed inspection standards. The non-compliance rate of inspection standards of the lights is 23.7% and main causes are damage, tinting, painting and coloration of head-lamp, number plate lamp, front-rear position lights, stop lamp and direction indicators of motorcycles. Also, 28.4% of motorcycles are dropped from the luminous intensity inspection standard. Motorcycle electrical system cannot be visually inspected. The motorcycle inspections standards are improved reflecting 187 cases of real-world motorcycle inspection results.

• ETRI Journal
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• v.20 no.2
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• pp.192-213
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• 1998

The current approaches in Object-Oriented Analysis have limitations on modeling complex real world systems because they require priori knowledge about objects and their interactions before applying them. This may be practical in small systems and systems with clear domain knowledge, but not in large real world systems with unclear domain knowledge. Our approach uses a stepwise refinement technique in a top-down manner to the Object-Oriented Analysis stage with the application of use cases. This approach is especially good for new areas where we do not know all the information in advance. We present the approach with an example of its application to the B-ISDN service modeling and distributed systems.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.122-125
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• 1997

It is needless to say that the hemodynamic variables estimation is a very important study or the artificial heart. Even though its importance there have not been satisfactory results which can be applied to the real-world situations. In this paper, we propose a practical afterload model ( AoP, PAP) which can be applied to the real-world situation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.06a
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• pp.89-94
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• 1997

In this paper, we present a VR-based interface method which provides users more natural, realistic, and interactive communication and collaboration tool. Since most services in the communication systems matches with the services in the real world, the best understanding would be achieved when the communication services are represented in accordance with the services in the real world. However, conventional text-based interface and 2D GUI cannot provide such reality to the users. In this paper, we discuss VR-based interface to overcome such difficulty and introduce one instance of communication system using the VR-based realistic, what we call Virtual Village, which we are currently developing. This application might be applied to education in virtual space, desktop conferencing system, and entertainment such as MUD or the games in the distributed environment, etc.

• The Journal of Korea Robotics Society
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• v.3 no.2
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• pp.117-122
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• 2008

This paper presents a multi-robot localization based on multidimensional scaling (MDS) in spite of the existence of incomplete and noisy data. While the traditional algorithms for MDS work on the full-rank distance matrix, there might be many missing data in the real world due to occlusions. Moreover, it has no considerations to dealing with the uncertainty due to noisy observations. We propose a robust MDS to handle both the incomplete and noisy data, which is applied to solve the multi-robot localization problem. To deal with the incomplete data, we use the Nystr$\ddot{o}$m approximation which approximates the full distance matrix. To deal with the uncertainty, we formulate a Bayesian framework for MDS which finds the posterior of coordinates of objects by means of statistical inference. We not only verify the performance of MDS-based multi-robot localization by computer simulations, but also implement a real world localization of multi-robot team. Using extensive empirical results, we show that the accuracy of the proposed method is almost similar to that of Monte Carlo Localization(MCL).

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.5
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• pp.136-144
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• 2013

An extensive real world in-depth crash accident data is needed to make a precise occupant injury risk prediction at crash accidents which might be a critical information from the scene of the accident in ACNS(Automatic Crash Notification System). However it is rather unfortunate that there is no such a domestic database unlike other leading countries. Therefore we propose a numerical method, i.e., crash simulation using a sled model to make a virtual database that can substitute car crash database in real world. The proposing crash injury risk prediction is validated against a limited domestic crash accident data.

• Journal of Information Technology Applications and Management
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• v.10 no.1
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• pp.35-46
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• 2003

This study focuses on the effect of Social Scaffolding of virtual community on its growth and thrift. The research model proposed in this study is that communities, which have goof social scaffolding, tend to grow and thrive. Social Scaffolding refers to those aspects of a site Purpose, Places, Profiles, leaders, Roles, Rules, Cyclic Events, integrating with the real world, and Subgroups. The data were collected from 100 virtual communities in Daum Communications and analyzed in this study. Multiple regression is used to analyze the relationship of variables. The result is following ; purpose, loaders, rules, integrating with the real world support the effects of social scaffolding of virtual community on its growth and thrift, but profiles, roles, cyclic events do not. The result of this study implies the importance of social scaffolding of virtual community for re-searches, and developers.