• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1543-1546
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• 2003

잘못된 명세로 인한 자원의 손실을 악기 위해서는 반드시 명세에 대한 검증이 필요하다. 객체지향 모델링 언어의 표준인 UML은 각각의 다이어그램이 사용자의 요구사항을 정확히 반영하고 있는지를 검증하기가 매우 어렵다. 본 논문은 UML의 여러 다이어그램 중 상태 다이어그램(Statechart Diagram)의 명세에 발생해서는 안되는 상태 또는 발생할 수 없는 상태와 같은 오류의 존재여부 등의 정확성을 검증하기 위해 CTL을 이용한 정형검증도구인 SMV를 이용한다. 이를 위해 UML의 상태 다이어그램에서 상태 정보와 상태 천이 정보를 추출하여 SMV로 변환하는 규칙을 찾아내어 UML의 상태 다이어그램의 정확성 검증을 수행하는 방법을 제안하고 자동으로 변환하는 툴을 설계한다.

• Annual Conference on Human and Language Technology
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• 2022.10a
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• pp.497-501
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• 2022

대화 상태 추적(Dialogue State Tracking)은 특정 목적을 달성하기 위한 대화 시스템인 목적 지향 대화 시스템의 핵심 부분으로, 대화에서 표현된 사용자의 목적을 추출한다. 조기 위험 검출 시스템은 연속적으로 들어오는 정보를 바탕으로 분류 대상인지 아닌지를 판별하며, 정확도 저하를 피하면서 최대한 빠르게 분류하는 것을 목표로 한다. 본 연구에서는 대화 상태 추적 시스템에서 나온 은닉층을 입력으로 하여 실시간으로 공황 장애 여부를 점진적으로 조기 분류하는 시스템과 조기 분류를 위한 새로운 손실 함수를 제안한다. 조기 위험 검출 시스템에 대화 상태인 belief state의 정보를 함께 사용했을 때, 큰 성능 향상을 보였으며 대화 상태가 조기 위험 검출에 필요한 정보를 담고 있음을 확인할 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2A
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• pp.176-186
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• 2006

In this paper, we propose an enhanced symbol detector algorithm for 2.45GHz LR-WPAN(Low-Rate Wireless Personal Area Network) receiver. Because the frequency offset of $\pm$80ppm on 2.45GHz band is recommended in IEEE 802.15.4 LR-WPAN(Low-Rate Wireless Personal Area Network) specification, a symbol detector algorithm having stable operation in the channel environment with large frequency offset is required. For robustness to the frequency offset, non-coherent detection-based symbol detector algorithm is typically applied in the LR-WPAN receiver modem. However, the noncoherent symbol detector has increased performance degradation and hardware complexity due to squaring loss of I/Q squaring operation. Therefore we propose a coherent detection-based symbol detector algorithm with frequency offset compensation using a preamble symbol. The proposed algorithm is more suitable for LR-WPAN receiver aimed at low-cost, low-power and low-complexity than the non-coherent symbol detector, since it can reduce performance degradation due to squaring loss of I/Q squaring operation and implementation complexity. Simulation results show that the proposed algorithm has performance improvement of about 1dB in various channel environments.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.191-196
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• 2013

In this paper, the interaural intensity difference (IID)-based sounr source separation method in closely spaced stereo omnidirectional microphones is proposed. First, in order to improve the channel separability, a minimum variance distortionless response (MVDR) beamformer is employed to increase the intensity difference between stereo channels. After that, IID-based sound source separation method is applied. In order to evaluate the performance of the proposed method, source-to-distortion ratio (SDR), source-to-interference ratio (SIR), and sources-to-artifacts ratio (SAR), which are defined as objective evaluation criteria in stereo audio source separation evaluation campaign (SASSEC), are measured. As a result, it was shown from the objective evaluation that the proposed method outperforms a sound source separation method without applying a beamformer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3A
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• pp.282-290
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• 2006

In this paper, we propose an enhanced Timing Estimator algorithm for 2.45GHz LR-WPAN receiver. Because an expensive and highly efficient oscillator can't be used for low-cost implementation, a Timing Estimator algorithm having stable operation in the channel environment with center frequency tolerance of 80 ppm is required. To enhance the robustness to frequency offset and the stability of receiver performance, multiple delay differential filter is adopted. By utilizing the characteristic that the correlation result between the output signal of Multiple delay differential filter and reference signal is restricted on the In-phase part of the correlator output, a coherent detection scheme instead of the typical noncoherent one is adopted for Timing Estimator. The application of the coherent detection scheme is suitable for LR-WPAN receiver aimed at low-cost, low-power, and low-complexity, since it can remove performance degradation due to squaring loss of I/Q squaring operation and decrease implementation complexity. Computer simulation results show that the proposed algorithm achieved performance improvement compared with the differential detection-based noncoherent scheme by 2dB in average.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.5
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• pp.501-509
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• 2002

SGML(ISO 8879) has been proliferated to support various document styles and to transfer documents into different platforms. SGML documents have logical structure information in addition to contents. As SGML documents are widely used, there is an increasing need for database storage and retrieval system using the logical structure of documents. However. traditional search engines using document indexes cannot exploit the logical structure. In this Paper, we have developed an SGML document storage system, which is DTD-independent and store the document type and the document instance separately by using Grove which is the document model for DSSSL and HyTime. We have used the Object Store, an object-oriented DBMS, to store the structure information appropriately without any loss of structural information. Also, we have supported a index structure for search efficiency like the relational DBMS, and constructed an effective user interface which combines content-based search with structure-based search.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2596-2604
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• 1997

There are two kinds of backends in ACK:code generator(full-fledged backend) and code expander(fast backend). Code generators generate target code using string pattern matching and code expanders generate target code using macro expansion. ACK translates EM to SPARC code using code expander. The corresponding SPARC code sequences for a EM code are generated and then push-pop optimization is performed. But, there is the problem of maintaining hybrid stack. And code expander is not considered to passes parameters of a procedure call through register windows. The purpose of this paper is to improve SPARC code quality. We suggest a method of SPARC cod generation using EM tree. Our method is divided into two phases:EM tree building phase and code expansion phase. The EM tree building phase creates the EM tree and code expansion phase translates it into SPARC code. EM tree is designed to pass parameters of a procedure call through register windows. To remove hybrid stack, we extract an additional information from EM code. We improved many disadvantages that arise from code expander in ACK.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.7-13
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• 2007

In this paper, we have designed and fabricated a small size wide-band monopole antenna which can integrate the frequency of previous business mobile communication system by adding 4 PCS of post type parasitic element on top-loaded sleeve monopole antenna. We have observed the properties of return loss upon a parameter change of element, and we also examined radiation properties in the band of PCS, W-CDMA, WiBro, W-LAN and S-DMB in order to make sure the suggested antenna's wide-band properties. We have found that the proposed antenna has omni-direction in horizontal plane and figure eight-direction in vertical plane, and we could have good return loss($Return\;loss{\leq}-10\;dB$) and $1.14{\sim}3.66\;dBi$ gain in $1.67{\sim}3.55\;GHz$ of frequency range($B/W{\fallingdotsep}72%$).

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.6
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• pp.105-110
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• 2012

In this paper, A planar UWB antenna with notched WLAN band, 802.11a band (5.15 ~ 5.825GHz), by using slot and slit is designed by using CST Microwave Studio. The notched bandwidth can be controlled by the length and width of the slot and slit in the patch and ground plane and it's radiation characteristics are examined through the experiments. The bandwidth based on the -10dB return loss level can be covered the full UWB band (3.1 ~ 10.6GHz) with a notched WLAN band (5.147 ~ 5.83GHz). Also, the experimental radiation pattern is almost omnidirectional in the H-plane.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1991.10a
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• pp.96-101
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• 1991

프리스트레스트 콘크리트 교량은 콘크리트와 PS 강재의 역학적 장점들을 십분 활용하여 경제적인 단면 구성이 가능한 반면, 서로 다른 두 재료의 복합적인 특성들 즉, 콘크리트의 크리이프 (creep), 건조수축 (shrinkage)과 PS 강재의 이완 (relaxation) 등과 같이 시간에 따라 변화하는 인자들로 인하여 복잡한 구조적 거동을 보여 해석상 어려움이 따른다. 이와같은 복합거동은 시공순서와 시공방법에 의해 시공중의 구조계와 지지조건 등이 변화하는 경우에는 더욱 복잡한 양상을 띄게 된다. 뿐만 아니라 박스 거더와 같은 박벽요소에서는 일반적인 보요소(beam element)로는 나타낼 수 없는 ？(warping)을 무시할 수 없으므로 ？ 자유도를 구현할 수 있는 특수한 기능의 구조해석용 프로그램의 개발이 절실히 요망된다. 그리고 시공단계별로 출력되는 많은 양의 수치결과들을 설계와 시공실무자에 지향된 형태로 조합, 변형시켜 그래픽 화면상에 나타내는 후처리 프로그램(Post-processor) 기능도 구조해석용 프로그램의 개발 못지않게 중요하다. 본 연구의 목적은 삼성종합건설과 서울대 토목공학과가 공동으로 ？(warping) 자유도를 포함한 7개의 자유도를 갖는 3차원 보요소를 사용하여 PS 콘크리트의 재료적 특성인 크리이프와 건조수축, 그리고 강재의 이완(relaxation)을 포함한 프리스트레싱력의 손실을 고려할 수 있고 시공 단계별 구조계의 변화 및 지지조건들의 다양한 변화를 효율적으로 모사할 수 있는 프로그램의 개발에 있다.