• Proceedings of the Korean Society for Cognitive Science Conference
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• 2005.05a
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• pp.171-176
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• 2005

본 논문에서는 진단시스템의 추론성능을 향상시키기 위한 방법으로서, 사례 기반 추론을 통해서 규칙 기반 추론의 단점을 보완하여 성능을 향상시키는 혼합형 추론 모델을 제안한다. 본 모델의 특징은 규칙 기반 추론의 확장성 문제와 규칙화 할 수 없는 예외적인 상황에 대한 문제점을 사례 기반 추론에서 사례로 저장하여 규칙 기반 추론의 단점을 보완하는데 있다. 이런 두 모델의 문제점을 해결하는 과정은 첫째로, 문제에 따라 규칙기반추론 모듈의 베이스를 통해서 적절한 규칙을 적용 후 추론을 적용하여 근접한 해를 얻어낸다. 두 번째로, 규칙베이스에 저장되어 있지 않은 문제에 대해서는 사례 라이브러리를 검색하고 유사성 검사를 통해서 저장된 사례를 찾아 입력된 사례에 적용하여 문제를 해결한다. 셋째로, 해결된 문제에 대해서 수정작업을 통해 사례 라이브러리를 확장한다. 이와 같이 세 과정을 통해 본 논문에서 제안하는 방법론의 성과를 측정하기 위하여 정비 메뉴얼을 규칙화하여 규칙베이스를 구축하였고 전문가들의 경험적인 지식에 대해서는 사례라이브러리로 구축하였다. 또한 지식베이스를 통해서 진단을 수행하고 해결된 문제에 대해서 정확도 검사를 통해 진단의 정확성을 측정하여 혼합형추론엔진의 성능을 검증하였다.

• Korean Journal of Cognitive Science
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• v.10 no.2
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• pp.17-25
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• 1999

In developing a Korean database interfacing system exist many difficult problems which are not usually pointed out in developing an English version. Basically the difficulty in implementing deep level Korean database interfacing system lies in the fact that Korean has fewer syntactic restrictions. This means that while less burden will be placed on semantic analysis more burden will be placed on contextual processing for Korean when compared to English. This paper discusses various difficulties which we came across while developing a prototype Korean DB interfacing system (the Korean Core L Language Engine) especially focusing on issues of representing and resolving Quasi Logical Forms.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.2
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• pp.81-87
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• 2013

In this paper, we present an implementation of Long Term Evolution (LTE) Uplink (UL) system on a Software Defined Radio (SDR) platform using a conventional Personal Computer (PC), which adopts Graphic Processing Units (GPU) and Universal Software Radio Peripheral2 (USRP2) with URSP Hardware Driver (UHD) for SDR software modem and Radio Frequency (RF) transceiver, respectively. We have adopted UHD because UHD provides flexibility in the design of transceiver chain. Also, Cognitive Radio (CR) engine have been implemented by using libraries from UHD. Meanwhile, we have implemented the software modem in our system on GPU which is suitable for parallel computing due to its powerful Arithmetic and Logic Units (ALUs). From our experiment tests, we have measured the total processing time for a single frame of both transmit and receive LTE UL data to find that it takes about 5.00ms and 6.78ms for transmit and receive, respectively. It particularly means that the implemented system is capable of real-time processing of all the baseband signal processing algorithms required for LTE UL system.

• Science of Emotion and Sensibility
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• v.21 no.4
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• pp.43-54
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• 2018

The aim of this study is to determine the effect of motion sickness on pupil rhythm. Sixteen volunteers of both genders (8 male, 8 female, mean age $25.67{\pm}2.43$ years) experienced VR contents in both 2D and HMD versions for 15 minutes, and their pupillary rhythms were compared. The irregular pattern of the pupillary rhythms, as demonstrated by increasing mean pupil diameter (mPD) and standard deviation of the pupil diameter (sPD), revealed motion sickness after experiencing HMD condition. The pupillary response is strongly related to the cognitive load, and the motion sickness can be interpreted as a change in the cognitive load caused by the increasing volume of visual information that must be processed and the conflict or inconsistency between different sensory modalities. The method proposed in this study could be a non-contact measurement method for the monitoring of motion sickness using a web-camera rather than previous sensor-based methods.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.02a
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• pp.7-11
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• 2008

최근의 로봇에 대한 연구를 살펴보면 인간-로봇 상호작용과 시스템의 통합에 관련된 연구가 증가하고 있음을 알 수 있다. 또한 인식 및 인지에 관련된 요소기술들은 이미 상당한 수준에 올라서 있다. 이를 바탕으로 전 세계적인 로봇연구의 추세는 요소기술들의 통합을 통하여 완전한 개체로서의 로봇을 만들려고 하고 있으며 상업화된 시장으로 끌어내려는 쪽으로 변화하고 있다. 그러나 로봇을 상업화된 시장으로 끌어내기 위한 다양한 연구와 노력에도 불구하고 많은 부분에서 부족한 것이 현실이며, 지금까지 개별적으로 개발된 각 요소기술의 통합 또한 필수적이다. 특히 인간과 비슷한 인지능력의 확보를 위한 불확실성 극복능력과 개별적인 요소기술의 성능에만 의지하지 않는 인식능력의 확보는 서비스로봇의 신뢰성 향상을 위하여 필수적이다. 본 논문에서는 이러한 문제를 해결하기 위해서 행위적 인지 개념을 제안하였으며 Cognitive Robotic Engine을 통하여 이를 구현하여 상용화된 서비스로봇 플랫폼에 적용하여 실험하였다.

• Journal of Communications and Networks
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• v.16 no.6
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• pp.600-612
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• 2014

In this paper, we consider the problem of spectrum sensing for advanced television systems committee (ATSC) digital television (DTV) signal detection. To exploit the cyclostationarity of the ATSC DTV signals, we employ spectral correlation density (SCD) as the decision statistic and propose an optimal detection algorithm. The major difficulty is in obtaining the probability distribution functions of the SCD. To overcome the difficulty, we probabilistically model the pilot frequency location and employ Gaussian approximation for the SCD distribution. Then, we obtain a practically implementable detection algorithm that outperforms the industry leading systems by 2-3 dB. We also propose various techniques that greatly reduce the system complexity with performance degradation by only a few tenths of decibels. Finally, we show how robust the system is to the estimation errors of the noise power spectral density level and the probability distribution of the pilot frequency location.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.11
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• pp.938-943
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• 2013

In this paper, we propose a transmission parameter optimization scheme based on genetic algorithm for dynamic spectrum access systems. Specifically, we represent a multiple objective fitness function as a weighted sum of single objective fitness functions to optimize transmission parameters, and then, obtain optimized transmission parameters based on genetic algorithm for given transmission scenarios. From numerical results, we confirm that the transmission parameters are well optimized by using the proposed optimization scheme.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.461-467
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• 1998

Although many methods of knowledge acquisition has been developed in the expert systems field, such a need for causal knowledge acquisition has not been stressed relatively. In this respect, this paper is aimed at suggesting a causal knowledge acquisition process, and then investigate the causal knowledge-based inference process. A vehicle for causal knowledge acquisition is FCM (Fuzzy Cognitive Map), a fuzzy signed digraph with causal relationships between concept variables found in a specific application domain. Although FCM has a plenty of generic properties for causal knowledge acquisition, it needs some theoretical improvement for acquiring a more refined causal knowledge. In this sense, we refine fuzzy implications of FCM by proposing fuzzy implications of FCM by proposing fuzzy causal relationship and fuzzy partially causal relationship. To test the validity of our proposed approcach, we prototyped a causal knowledge-driven inference engine named CAKES and then experime ted with some illustrative examples.

• Korean Journal of Cognitive Science
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• v.3 no.2
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• pp.329-347
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• 1992

This paper deals with the results of development tools for knowldge base implementation on personal computers which is focused on university's student affairs as the education sector.Tje consultant expert system consists of the inference system which makes the object-oriented inference possible by using the present typical rule-based expert systems organized with inference engine,knowledge base,and user interface the user interface management system providing a variety of interfaces,the knowlege managment system for the efficient management and acquirement of knowledge which is independently constucted,and the object management system for the effective management of these systems. This system's design is the consultant expert system'C-I(Consultant-One),in which users can consult with expert at the use's various points of view and which can be operated on the easily accessible personal compuers. We implemented the Student Affairs Administration Consultation Expert System(SACES)'which constructed the knowledge base for three fields of university student affairs management such as timetable management,curriculum and grade points.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.80-89
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• 2019

Prospecting future social environmental changes and improvement research on future technologies is required for prospecting promising technology, as it would be useful for institution·company to set up technical planning. This study aims at providing a methodology for retaining international technology competitiveness, marketable industry, and sustainable promising technology in a field of new growth engine industry such as national unmanned aerial vehicle industry. We draw a result by analysing with tools such as KrKwic, Excel, NetMiner, presenting methods of a Social Network Analysis, sub-group analysis, and cognitive map analysis based on patent data in a field of unmanned aerial vehicle industry. Therefore, this study explored the technology evolution of UAV and to prospect promising technology. As a result, some future promising technologies are prospected as what worths concentrated investment, such as 'system integration tech', 'assessment/airworthiness certification tech', 'avionics', 'pilot control tech', 'identification of friend or foe', 'flight control tech', 'supportive equipment'.