• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.12-18
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• 2021

The purpose of this study is to effectively mitigate the bending displacement that occurs in the bridge due to forced vibration. We developed CTMD (Combine Tuned Mass Damper) that combines the relationship between spring and mass to control the bending behavior of simple beams. The experiment was conducted to confirm the control effect according to the change in the mass ratio of the developed CTMD. The developed CTMD is designed and manufactured so that the mass ratio can be adjusted according to the characteristics of the bridge. The maximum load of the spring applied to CTMD was fixed at 33.15 N. In order to evaluate the performance of the developed CTMD, a simple beam composed of hinges and rollers as boundary conditions was fabricated. In the experimental method, a CTMD was installed in the center of a simple beam and the deflection displacement according to the mass ratio was measured. The shaking condition was shaken at 3 Hz to induce the maximum bending behavior of the simple beam. As a result of the experiment, it was confirmed that when the optimal mass ratio was 2.1, the damping rate of the bending behavior displacement was about 71.2 %, indicating the best control effect.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.3
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• pp.115-122
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• 2019

For Korean phoneme recognition, Hidden Markov-Gaussian Mixture model(HMM-GMM) or hybrid models which combine artificial neural network with HMM have been mainly used. However, current approach has limitations in that such models require force-aligned corpus training data that is manually annotated by experts. Recently, researchers used neural network based phoneme recognition model which combines recurrent neural network(RNN)-based structure with connectionist temporal classification(CTC) algorithm to overcome the problem of obtaining manually annotated training data. Yet, in terms of implementation, these RNN-based models have another difficulty in that the amount of data gets larger as the structure gets more sophisticated. This problem of large data size is particularly problematic in the Korean language, which lacks refined corpora. In this study, we introduce CTC algorithm that does not require force-alignment to create a Korean phoneme recognition model. Specifically, the phoneme recognition model is based on convolutional neural network(CNN) which requires relatively small amount of data and can be trained faster when compared to RNN based models. We present the results from two different experiments and a resulting best performing phoneme recognition model which distinguishes 49 Korean phonemes. The best performing phoneme recognition model combines CNN with 3hop Bidirectional LSTM with the final Phoneme Error Rate(PER) at 3.26. The PER is a considerable improvement compared to existing Korean phoneme recognition models that report PER ranging from 10 to 12.

• Journal of Digital Convergence
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• v.12 no.4
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• pp.443-454
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• 2014

This study designed to know subjective structure about clinical experience of adaptation of new nursing staffs in a general hospital and using Q-methodology. Using Q-methodology, 40 new nursing staffs sorted working a general hospital through personal interview. The statement positions on the sorting continuum were scored from +4(representing the highest level of agreement) through 0(at the neutral position on the continuum) through to -4(representing the highest level of disagreement). Factor analysis of the data was undertaken using PC QUANL program to determine if any patterns were discernible. The five types extracted all had eigenvalues greater than 1.0 and explained 62.38% of the variation in responses.: (1) New workload type, (2) Interest and responsibility type, (3) Improve the situation type, (4) Lack of knowledge and technology type, and (5) Excessive workload type. The significant differences found in the subjective structure of clinical experience of adaptation of new nursing staffs in ad general hospital. The findings of this study could contribute to the development of an effective programmes of education and personnel clinical practice strategies.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.3
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• pp.293-300
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• 2015

In this study, a series of forced vibration testing and ambient vibration measurement were performed at a lowrise masonry-infilled reinforced concrete frame structure before and after seismic retrofit and its dynamic properties were extracted using system identification techniques. Also, analytical models which show similar dynamic properties to the measures ones were constructed. The system identification results showed that damping ratios in x direction along which the dampers were installed has been increased. From the comparison between the analytical models, the effective stiffness of post-installed member and post-reinforced members(shear walls and damper frames) were only 50% of gross sectional stiffness of the members, which indicates that the these members were not fully integrated with the existing structure or members. In addition, support condition of post-installed footing has to be pinned in y direction to match the dynamic properties, which is seemingly caused by the change of fixity of the soil due to the installation of new footing.

• Explosives and Blasting
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• v.22 no.3
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• pp.13-26
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• 2004

This work reports results of our study on the dynamic response of buried pipelines depending on their boundary conditions. We have studied behavior of the buried pipelines both along the axial and the transverse direction with a boundary condition of free ends. The buried pipelines are modeled as beams on elastic foundation while the seismic wave as a ground displacement in the form of a sinusoidal wave. The natural frequency, its mode, and the effect of parameters have been interpreted in terms of the free vibration. In order to investigate the response on the earthquake, the resulting frequency and the mode shape obtained from the free vibration have been utilized to derive the mathematical formula for the farced vibration. We have also completed the computer program to simulate the time-displacement graphs of the pipe lines with free ends for both cases of vibrations.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.1_2
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• pp.35-43
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• 2006

An MPI Checkpointer is a tool which provides fault-tolerance through checkpointing The previous researches related to the MPI checkpointer have focused on automatic checkpointing and recovery capabilities, but they haven't considered portability issues. In this paper, we discuss design and implementation issues considered for portability when we developed an MPI checkpointer called STFT. In order to increase portability, firstly STFT supports the abstraction interface for a single process checkpointer. Secondly, STFT uses a user-based checkpointing method, and limits possible checkpointing places a user can make. Thirdly, STFT lets the MPI_Init create network connections to the other MPI processes in a fixed order. With these features, we expect STFT can be easily adaptable to various platforms and MPI implementations, and confirmed STFT is easily adaptable to LAM and MPICH/P4 with the prototype Implementation.

• Fire Science and Engineering
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• v.24 no.4
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• pp.116-122
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• 2010

The fire protection system of nuclear power plants shall be designed, constructed and operated, through a defense-in depth criterion to suppress the leakage of radioactivity to the outside and to allow the safety shutdown function when a fire occurs. In order to achieve these purposes, most of countries abroad operating the nuclear power plants keep up the integrated regulations, however we have two guidelines, the fire protection service act and the nuclear energy act, as mandatory requirements to apply to the fire protection systems in nuclear power plants. It has shown that USA, Canada and Japan which have long experience in operating nuclear power plants have regulations integrated technically for fire protection system of nuclear power plants. It is proposed that the things once verified the risk analysis of the fire hazard by the nuclear law in the design for fire suppression system in plants should be authorized by the fire protection service act as an exception.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.1933-1940
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• 1997

The development of CMOS IC chip and external system with optical transmission sytem is proposed in this paper, which deal with 4 subject 4 channel biological signals, receive and transmit biological signals to the external system using LED and infrared light of photodiode. This system decreases the dependency of power supply voltage to the COMS IC chip. A newenforce synchronization technique using infrared bi-directional communication has ben proposed. The telemetner IC with the size of $5.1{\times}5.1mm^2$ has the followingfunctions:receiving of command signal, initialization of internal state of all functional blocks, decoding of subject selection signal, time division multiplexing of 4-channel modulated biological signals, transmission of modulated signals to external system, and auto power down control. To confirm the total telemetry system, electrocardogram is transmitted and received to the external system using optical link.

• Cross-Cultural Studies
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• v.48
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• pp.253-287
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• 2017

The purpose of this study is to examine the ethnic phenomenon in the multi-layered context, based upon data collected from my fieldwork in Asella Town, Ethiopia. The town has experienced few ethnic conflicts at the collective level because of ecological conditions, the numerical balance between the two major ethnic groups-i.e., the Oromo and the Amhara-, frequent ethnic intermarriages as well as effects of a unique sociocultural practice of 'breast-feeding.' However, despite positive influences of such a practice, the local community has continuously witnessed discrimination and threats by the dominant ethnic group. Most of my informants feel that ethnic intermarriage contributes to: (i) enforcement of bonds among both ethic groups and community members, (ii) acquisition of different ethnic cultures, (iii) cultivation of the spirit of tolerance among people, and (iv) production of the superior second generation that has hybrid/multiple ethnic identities. However, some informants harbor negative attitudes towards ethnic intermarriage because they perceive it as a selfish choice of two parties and damages ethnic identity. Most informants consider ongoing Oromonization as natural, whereas others insist that it should be understood in the context of coercion, superficiality and survival strategy.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.2
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• pp.144-155
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• 2019

One of the issues of the automotive industry today is autonomous driving vehicles. In order to achieve level 3 or higher as defined by SAE International, harmonization of autonomous driving technology and connected technology is essential. Current vehicles have new features such as autonomous driving, which not only increases the number of electrical components, but also the amount and complexity of software. As a result, the attack surface, which is the access point of attack, is widening, and software security vulnerabilities are also increasing. However, the reality is that the essential security requirements for vehicles are not defined. In this paper, based on real attacks and vulnerability cases and trends, we identify the assets in the in-vehicle network and derive the threats. We also defined the security requirements and derived essential security requirements that should be applied at least to the safety of the vehicle occupant through risk analysis.