• 대한전자공학회논문지TC
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• 제44권7호통권361호
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• pp.88-95
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• 2007

본 논문에서는 다양한 방식의 MIMO 기법에 쉽게 적용이 가능한 송수신 시스템 모델을 제안하고 이들의 성능 분석 시 필요한 채널간의 상관 특성 획득이 가능한 MIMO 채널 모델을 제시한다. 실내 환경에서의 채널 모델링을 통하여 MIMO 채널 형성에 따른 안테나 사이의 간섭을 시뮬레이션을 통하여 획득하고 주파수 선택적 채널 하에서 MIMO-UWB 시스템의 성능을 분석한다. 특히 채널 전달함수의 역행렬 계산시 과다한 연산량을 줄이기 위하여, 임의의 한 수신안테나에서 각각의 송신 안테나 신호를 복원하며, 각 수신안테나에서 추정된 송신 신호를 결합하는 방법을 채택하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권3호
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• pp.1583-1598
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• 2019

Recently, software has increased in complexity and been applied in various industrial fields. As a result, the presence of software bugs cannot be avoided. Various bug severity prediction methodologies have been proposed, but their performance needs to be further improved. In this study, we propose a novel technique for bug severity prediction in cross projects such as Eclipse, Mozilla, WireShark, and Xamarin by using topic modeling and similarity (i.e., KL-divergence). First, we construct topic models from bug repositories in cross projects using Latent Dirichlet Allocation (LDA). Then, we find topics in each project that contain the most numerous similar bug reports by using a new bug report. Next, we extract the bug reports belonging to the selected topics and input them to a Naïve Bayes Multinomial (NBM) algorithm. Finally, we predict the bug severity in the new bug report. In order to evaluate the performance of our approach and to verify the difference between cross projects and single project, we compare it with the Naïve Bayes Multinomial approach; the Lamkanfi methodology, which is a well-known bug severity prediction approach; and an emotional similarity-based bug severity prediction approach. Our approach exhibits a better performance than the compared methods.

• 한국전자통신학회논문지
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• 제14권5호
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• pp.825-836
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• 2019

군 병력의 효율적 운용을 위한 정보공유의 수단으로서 높은 망 유연성을 제공할 수 있는 드론형 기지국이 최적의 플랫폼이 될 것으로 예상된다. 또한 넓은 대역폭을 활용 가능한 밀리미터파 주파수대역은 대용량 데이터를 송수신하는데 적합하지만 shadowing에 취약한 특성을 가지게 되는데, 자유롭게 고도를 조절할 수 있는 드론형 기지국의 특성을 활용하면 LoS를 안정적으로 확보하여 취약점을 상쇄할 것으로 기대된다. 본 논문에서는 다양한 요소가 반영된 드론형 기지국의 성능분석을 위한 모델링을 수행함으로써, 차후 군 통신망으로써 활용가능성이 기대되는 드론형 기지국의 성능평가에 대한 틀을 제공하고자 한다.

• 한국시뮬레이션학회논문지
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• 제19권2호
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• pp.157-164
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• 2010

우수하고 신뢰성 있는 통신 시스템의 개발을 위해 시스템에 대한 기능 검증과 성능 평가가 모두 필수적인데 반해 이들은 주로 형식 언어 도구를 이용한 기능 모델링과 전문 네트워크 성능 평가 도구에 의한 성능 모델링을 통해 개별적으로 수행되어 왔다. 그러나 한 시스템을 별도로 중복하여 모델링 하는 것은 비용의 증가와 모델 간 불일치를 가져오게 된다. 본 논문은 이 문제를 해결하기 위해 SDL-OPNET 코-시뮬레이션을 통해 SDL로 설계된 통신 프로토콜의 성능을 평가하는 통합 설계 기법을 제안한다. 제안 기법은 Tau의 환경함수와 OPNET의 외부시스템 모듈을 이용하는 코-시뮬레이션 시스템의 설계 방법을 제시한다. InRes 프로토콜이 예로 사용되어 제안 기법의 적용가능성과 효용성을 보여준다.

• 대한산업공학회지
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• 제22권2호
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• pp.277-302
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• 1996

The overall performance of BISDN depends significantly on the interconnection network or the switch fabric. Hence, it is extremely important to evaluate the performance of the network or the fabric. The well developed performance models also provide insight into the factors that determine design tradeoffs as well as quantitative estimates of their importance. The objective of this paper is to investigate and critically compare all the developed performance analysis models of FPS according to internal switch fabric structure, traffic assumptions, performance measures, methodologies, etc. FPSs are described according to their internal fabric structure. Brief history of FPS performance analysis is mentioned and performance analysis modeling is discussed.

• Journal of information and communication convergence engineering
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• 제5권2호
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• pp.159-163
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• 2007

RFID applications are mostly associated with the timestamp when the events occur. For managing RFID data we need to design data modeling for RFID data to support monitoring and temporal queries. In this paper, we propose a temporal RFID data modeling to maintain the history of events and state changes and to monitor the states of RFID objects. This data modeling involves essential basic operations for RFID data to monitor the information of RFID objects and to support temporal queries. Filter operations can achieve better query performance and obtain efficient storage space usage. It is possible to adapt into different temporal business applications.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.265-271
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• 1997

A bond graph modeling approach which is equivalent to a finite element method is formulated in the case of the piezoelectric thickness vibrator. This formulation suggests a new definition of the generalized displacements for a continuous system as well as the piezoelectric thickness vibrator. The newly defined coordinates are illustrated to be easily interpreted physically and easily used in analysis of the system performance. Compared to the Mason equivalent circuit model, the bond graph model offers the primary advantage of physical realizability. Compared to circuit models based on standard discrete electrical elements, the main advantage of the bond graph model is a greater physical accuracy because of the use of multiport energic elements. While results are presented here for the thickness vibrator, the modeling method presented is general in scope and can be applied to arbitrary physical systems.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.86-89
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• 2003

To model a numerical problem space under the limitation of available data, we need to extract sparse but key points from the space and to efficiently approximate the space with them. This study proposes a sampling method based on the search process of genetic algorithm and a space modeling method based on least-squares approximation using the summation of Gaussian functions. We conducted simulations to evaluate them for several kinds of problem spaces: DeJong's, Schaffer's, and our original one. We then compared the performance between our sampling method and sampling at regular intervals and that between our modeling method and modeling using a polynomial. The results showed that the error between a problem space and its model was the smallest for the combination of our sampling and modeling methods for many problem spaces when the number of samples was considerably small.

• Journal of the Korean Data and Information Science Society
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• 제17권2호
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• pp.269-278
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• 2006

This paper presents the new hybrid data mining technique using error pattern, modeling of improving classification accuracy. The proposed method improves classification accuracy by combining two different supervised learning methods. The main algorithm generates error pattern modeling between the two supervised learning methods(ex: Neural Networks, Decision Tree, Logistic Regression and so on.) The Proposed modeling method has been applied to the simulation of 10,000 data sets generated by Normal and exponential random distribution. The simulation results show that the performance of proposed method is superior to the existing methods like Logistic regression and Discriminant analysis.

• Journal of the Korean Data and Information Science Society
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• 제16권3호
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• pp.683-693
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• 2005

This paper presents a new transmembrane Protein topology prediction method which is an attempt to model the topological rules governing the topogenesis of transmembrane proteins. Context-dependent structural regions of the transmembrane protein are used as basic modeling units in order to effectively represent their topogenic roles during transmembrane protein assembly. These modeling units are modeled by means of a tied-state hidden Markov model, which can express the position-specific effect of amino acids during ransmembrane protein assembly. The performance of prediction improves with these modeling approaches. In particular, marked improvement of orientation prediction shows the validity of the proposed modeling. The proposed method is available at http://bioroutine.com/TRAPTOP.