• The Journal of the Acoustical Society of Korea
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• v.16 no.2E
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• pp.14-20
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• 1997

The future teleconferencing systems will need an appropriate system which controls properly the acoustic echo for the convenient communication. The conventional acoustic echo cancellation algorithms involve large adaptive filters identifying the impulse response of the echo path. The use of adaptive IIR filters appears to be a reasonable way to reduce computational complexity. Effective cancellation of acoustic echo presented in teleconferencing system requires that adaptive filters have a rapid convergence speed. One of the main problems of acoustic echo cancellation techniques is that the convergence properties degrade for an highly correlated signal input such as speech signals. By the way, the introduction of linear prediction filers onto the structure of the acoustic echo cancellation represents one approach to decorrelate the speech signal. And variable step-size LMS algorithm improves the convergence speed through a little increasing of computational complexity. In this paper, we applied these two methods to the acoustic echo canceller(AEC) and showed that these methods have better performances than the conventional AEC.

• The Journal of the Acoustical Society of Korea
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• v.27 no.1E
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• pp.17-24
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• 2008

Blind speech separation (BSS) is well-known as a powerful technique for speech enhancement in many real world environments. In this paper, we propose a new application of BSS - acoustic echo cancellation (AEC) in a car environment. For this purpose, we develop a block-online BSS algorithm which provides robust separation than a batch version in changing environments with moving speakers. Simulation results using real world recordings show that the block-online BSS algorithm is very robust to speaker movement. When combined with AEC, simulation results using real audio recording in a car confirm the expectation that BSS improves double talk detection and echo suppression.

• Journal of The Korean Digital Architecture Interior Association
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• v.9 no.1
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• pp.83-90
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• 2009

Building Information Modeling (BIM) has the great possibility of transforming the AEC industry. BIM will require increased information exchange and mutual collaboration between all stakeholders. BIM implementation and such increased collaboration can affect legal issues and contract provisions. And some legal issues accompanying BIM Implementation will be raised while a large change also comes in responsibility and role between all stakeholders. However, current standard agreement system is based on fragmented agreement between the architect and the owner, and between the owner and the contractor. Another legal obstacles and considerations associated with BIM implementation will be arose from BlM technology and use of BIM. AEC professionals in Korea have long utilized the standard agreement forms as well and look forward complementation of current standard agreement for BlM implementation. Such complement direction for the standard agreement will be examined by investigating the legal issues and overview comparison between AlA E202 and ConsensusDOCS 301.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.490-492
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• 1998

In this paper, fuzzy-PD control system is designed to control angle and position of the inverted pendulum. To optimize parameters of fuzzy-PD controller, we used adaptive evolutionary computation(AEC). AEC uses a Genetic A1gorithm(GA) and an Evolution Strategy(ES) in an adaptive manner in order to take merits of two different evolutionary computations.

• International Journal of High-Rise Buildings
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• v.3 no.4
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• pp.279-283
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• 2014

This paper introduces two platforms created by the development team at CORE studio, Thornton Tomasetti's global innovation studio. Collaborative platforms change the way that parties communicate and develop projects. Wikipedia is one of many great examples for a platform that supports collaborative development of a product - the world's largest encyclopedia. In the AEC industry, no such platform exists that can be used for collaborative development of a building project, and hence, information exchange between the parties involved, and modeling programs used in a project is slow and opaque. The platforms introduced in this paper allow for much greater transparency at all stages of the building design process, and hence improve the flow of information between parties involved in the process, both firm-internal and external. While traditionally, the use of a large number of different modeling and analysis platforms is hard to manage by a project team; this paper introduces methods that strengthen the design process by using a multitude of programs needed in the different building design phases.

• Construction Engineering and Management
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• v.16 no.6
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• pp.45-49
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• 2015

• Journal of radiological science and technology
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• v.41 no.3
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• pp.249-254
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• 2018

In this study, we evaluated the DAP(Dose Area Product) reduction effect of the newly developed IRIS collimator by measuring the DAP of the Rectangle collimator and the IRIS collimator depending on the field, SID(Source to Image recpetor Distance) change, and AEC mode use. The results were as follows. The IRIS collimator decreased DAP by 34.91, 29.33, and 29.04%, respectively, compared to the Rectangle collimator when the field was increased to $8{\times}8$, $12{\times}12$, $16{\times}16inch$. And also, when the SID was increased to 100, 120 and 140 cm, the IRIS collimator decreased DAP by 10.73, 33.68 and 46.22%, respectively, compared to the Rectangle collimator. In AEC mode and none-AEC mode, DAP in IRIS collimator was reduced by 32.71 and 21.69%, respectively, compared with the Rectangle type. The IRIS collimator can reduce DAP by 29.62% on average compared to Rectangle type, which is statistically significant. These results suggest that the newly developed IRIS collimator can be used in medical field to alleviate radiation exposure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.287-294
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• 2017

BIM technology has been used in the domestic AEC field since the middle 2000s. BIM has proved its worth in cutting-edge buildings, mega-buildings and freeform buildings in particular. Many freeform buildings could not be completed due to the low level of construction technique. However, many successful cases emerged after adopting digital technology, including BIM which encouraged architects to challenge freeform designs. The modeling software that can generate the freeform shape are not usually able to build the efficient BIM data type in the AEC industry. In this study a process model of the parametric freeform construction member generation and conversion to BIM data is shown and the prototype system is demonstrated.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.421-426
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• 2011

This research was accomplished to assess dose effects on image quality at computed radiography (CR). The ultimate target of the research was finding optimized exposure that provides necessary image quality for the clinical chest diagnosis. Modulation transfer function (MTF), normalized noise power spectrum (NNPS), and Noise equivalent quanta (NEQ) corresponding to the different doses were measured for the assessment of image quality. The preparation of "edge test device" used in MTF measurement and experimental geometry setup were followed by the recommendations of International Electrotechnical Commission (IEC). The experimental results show the necessary image quality can be achieved even at a half of the automatic exposure control (AEC) setting dose for chest diagnosis. It means that the patient exposure can be reduced dramatically by using optimized dose.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.7
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• pp.61-70
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• 2017

In this paper, an Ethernet equalizer that compensates for automotive temperature variations within a broad range is presented. Communications in automotive systems have become increasingly important because of the many electronics in vehicles. Ethernet protocols are a good candidate for automotive communications. However, they should satisfy the AEC-Q100 requirements that stipulate an operational temperature range from -40 to $150^{\circ}C$. This paper proposes an Ethernet equalizer that can recover data up until 100 m length of CAT-5 cable adaptively within a temperature range of -40 to $150^{\circ}C$. To support the wide temperature range, a feedback system is used. The proposed equalizer has a bandwidth of 31.25 MHz with a fully-differential structure and is implemented in a Hynix $0.13{\mu}m$ BCDMOS technology.