• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.05a
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• pp.97-105
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• 1999

An important task for any software project manager is to be able to predict and control project size. Unfortunately, there is comparatively little work that deals with the problem of building estimation methods for software size in fourth-generation languages systems. In this paper, we propose a new estimation method for estimating for software size based on minimum relative error(MRE) criterion. The characteristic of the proposed method is insensitive to the extreme values of the observed measures which can be obtained early in the development life cycle. In order to verify the performance of the proposed estimation method for software size in terms of both quality of fit and predictive quality, the experiments has been conducted for the dataset I and II, respectively. For the data set I and II, our proposed estimation method was shown to be superior to the traditional method LS and RLS in terms of both the quality of fit and predictive quality when applied to data obtained from actual software development projects.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.15-21
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• 2020

In this paper, the observation performance of the electro-optical telescope system which surveils the unknown space objects, is analyzed by the Modeling & Simulation(M&S). The operation concept for the observation of the unknown space objects using two telescope systems is considered and the M&S models are constructed. Based on the operation concept for observing the unknown space objects, the estimated orbit is generated by Initial Orbit Determination(IOD) and the observation performance is analyzed according to the offset compensation cycle for the estimated orbit. The result of the M&S based analysis in this paper shows that the observation performance increases with the shorter offset compensation cycle, and decreases with the longer offset compensation cycle. Therefore, to improve the performance of the telescope system which surveils the unknown space objects, the observation system with accurate initial orbit determination or shorter offset compensation cycle should be designed and constructed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.10
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• pp.43-48
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• 2010

In general, in order to reduce an initial cell searching time, W-CDMA systems adopt a three-step cell search scheme: slot synchronization, frame synchronization, and primary scrambling code identification. We consider the second step (frame synchronization), in which a coherent detection using P-SCH (primary synchronization channel) is possible. In this paper, we propose a new coherent detection scheme, where a first order recursive filter is used to enhance channel estimation performance. Computer simulation results indicate that the detection performance of the proposed scheme can be robust over large range of frequency offset.

• Journal of the Korean Data and Information Science Society
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• v.27 no.4
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• pp.993-1000
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• 2016

Semi-supervised learning makes it easy to use an unlabeled data in the supervised learning such as classification. Applying the semi-supervised learning on the regression analysis, we propose two methods for a better regression function estimation. The proposed methods have been assumed different marginal densities of independent variables and different smoothing parameters in unlabeled and labeled data. We shows that the overfitted pilot estimator should be used to achieve the fastest convergence rate and unlabeled data may help to improve the convergence rate with well estimated smoothing parameters. We also find the conditions of smoothing parameters to achieve optimal convergence rate.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.217-219
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• 2004

본 연구에서는 Feedforward Neural Network에 적용될 수 있는 개선된 학습 알고리즘을 개발하고자 한다. 제시된 알고리즘을 이용하여 학습을 할 때 학습 초기는 가장 단순한 경우로써 한 개의 학습 패턴과 은닉 층으로부터 시작한다. 신경망 학습 중에 지역 최소값에 수렴되면 weights scaling 기법을 이용하여 지역 최소값을 벗어나도록 한다. 지역 최소값의 탈출이 용이하지 않으면 은닉노드를 점차적으로 추가한다. 이러한 단계에서 새롭게 추가된 노드에 대한 초기값 선택은 선형계획법을 이용한 최적 처리절차론 이용한다. 최적 처리절차의 결과로써 은닉 층의 노드가 추가된 후의 네트워크는 학습회수를 증가시키지 않아도 학습 허용오차를 만족시킬 수 있다 본 연구에서 적용한 개선된 알고리즘을 이용하면 신경망 학습시의 수렴 정도를 높여주고 최소한의 단순 구조를 갖는 신경망으로 추정할 수 있게 하며, 이 결과를 모의실험을 통하여 살펴보고 기존의 연구 결과와 비교한다.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.243-244
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• 2011

이 논문에서는 부하전류의 크기에 따라 시시각각 변하는 매입형 영구자석 동기전동기의 d, q 축 인덕턴스를 실시간으로 추정해 제어에 반영시킬 수 있는 방법을 제안했다. 정지상태에서 초기 기동에 필요한 인덕턴스 값을 추정해도 운전시 부하전류의 크기에 따라 인덕턴스가 변하기 때문에 모든 영역에서 같은 인덕턴스 값을 적용하면 성능을 제대로 내기 어렵다. 이 논문에서는 인덕턴스 오차에 따라 발생되는 지령전압과 계산전압의 차이를 이용해 이를 실시간으로 보정함으로써 부하 성능을 개선할 수 있다는 사실을 확인했다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.575-579
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• 2007

스마트 홈 환경에서 사용자 중심 서비스를 제공하기 위해서는 가전기기를 제어하고 네트워크에 연결하기 위한 미들웨어기술과 상황에 맞는 서비스를 제공하기 위해 사용자 위치 정보가 중요하다. 기존의 위치 시스템들은 장애물 등에 영향을 많이 받아 정확한 위치 정보를 얻을 수 없다는 단점이 있다. 본 논문에서는 OSGi 미들웨어 상에서 관성 센서와 RFID Reader를 이용하여 위치추적 시스템의 난점인 초기 위치설정 문제와 오차 누적 문제를 개선한 사용자 위치 추정 시스템을 설계하였다. 또한 스마트 홈 환경 안에서 본 논문에서 제안한 시스템이 장애물의 영향을 받지 않고 동작하는 것을 확인하였다.

• Korean Journal of Construction Engineering and Management
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• v.19 no.4
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• pp.82-92
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• 2018

Considering that earlier stage of construction project has a great influence on the possibility of lowering of environmental load, it is important to build and utilize system that can support effective decision making at the initial stage of the project. In this study, we constructed an environmental load estimation model that can be used at the early stage of the project using basic design factors. The model was constructed by using the artificial neural network to estimate environmental load by applying to planning stage (ANN-1), basic design stage (ANN-2). The result of test, shows that average of absolute measuring efficiency and standard deviation of ANN-1 and ANN-2 were 11.19% / 5.30% and 9.59% / 3.09% each. This result indicates that the model using the input variables extended with the project progress has high reliability and it is considered to be effective in decision support at the initial design stage of the project.

• Journal of the Korea Institute of Building Construction
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• v.21 no.1
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• pp.21-29
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• 2021

The objective of this study is to evaluate the effect of the application of double layered bubble sheet on the curing of slab and wall concrete placed at the job site in cold weather and to offer a feasibility of Concrete IoT Management System(CIMS), which is wireless sensor network developed by the authors, to manage early age quality of the concrete in terms of temperature, maturity and strength development. Test results indicated that the application of bubble sheet enhances the insulation performance, which results in an increase of the temperature by around 1~20. 6℃. It is found that CIMS can gather the temperature, maturity and strength development data from the sensors embedded from 30 m far from CIMS successfully. Predicted compressive strengths by CIMS had good agreement with measured ones within 2 MPa error level until 7 days. It is thought that the combination of the bubble sheet application for cold weather protection and CIMS for quality management tool in cold weather concreting contributes to shorten the time for the form removal by one day.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.10
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• pp.819-824
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• 2017

This paper presents a target localization scheme for distributed Multi-input Multi-output(MIMO) radar system using ToA measurements obtained from multiple transmitter and receiver pairs. The proposed method can locate the target from an arbitrary initial point by iteratively finding the Taylor linear approximation equation. The simulation results show that proposed method achieves the better mean square error(MSE) performance than the existing target localization methods, and furthermore, attains Cramer-Rao Lower Bound(CRLB).