• Journal of the Korean Data and Information Science Society
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• 제25권5호
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• pp.1151-1160
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• 2014

In DNA microarray studies, the number of genes far exceeds the number of samples and the gene expression measures are highly correlated. Partial least squares regression (PLSR) is one of the popular methods for dimensional reduction and known to be useful for the classifications of microarray data by several studies. In this study, we suggest a modified version of the partial least squares regression to analyze gene expression data with survival information. The method is designed as a new gene selection method using PLSR with an iterative procedure of imputing censored survival time. Mean square error of prediction criterion is used to determine the dimension of the model. To visualize the data, plot for variables superimposed with samples are used. The method is applied to two microarray data sets, both containing survival time. The results show that the proposed method works well for interpreting gene expression microarray data.

• 한국ITS학회 논문지
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• 제4권1호
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• pp.1-13
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• 2005

다양한 대중교통수단이 함께 구축되어 있는 통합대중교통망(Integrated Transit Network)에 대하여, 최적통행시간 경로정보뿐만 아니라 다수의 최적통행시간 정보를 제공하는 방안에 대한 기초연구는 그 사례를 찾아보기 어렵다. 본 연구는 다수의 대중교통경로를 탐색하기 위하여, 버스와 지하철의 두 수단이 함께 존재하는 복합교통망에서 K개의 최소통행시간을 갖는 경로를 탐색하는 방안을 제안한다 제안된 방안은 통행정보에서 대중교통 사용자가 일반적으로 필요로 하는 다음의 3가지 제약조건 (1) 수단의 서비스시간제약, (2) 통합거리비례제 요금제약, 3) 환승회수제약을 고려한다. 사례연구를 통해 K개의 최소통행시간 경로정보뿐만 아니라 위의 제약조건을 조합적으로 반영하여 사용자에게 필요한 경로정보의 질적 향상 및 다양화에 대한 가능성을 제시한다.

• 한국식생활문화학회지
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• 제10권2호
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• pp.75-81
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• 1995

This study was attempted to standard Yukwa recipies by proposing optimal conditions for soaking time and the number of beating. Soaking time and the number of beating had effects on the number of peak, implying that 15 days of soaking time at $15^{\circ}C$ and 160 times of beating would be required. In Yukwa's microstructural image, the better groups were over 15 days of soaking time and as number of beating increased, the appearance improved. The longer soaking time, the better tenderness and expansion volume. The number of beating had significant effects on all sensory evaluation except volume. Response surface model showed that the optimal condition would be at least 15 days of soaking and 319 times of beating.

• Journal of Communications and Networks
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• 제18권1호
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• pp.8-18
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• 2016

In this paper, we propose a number of blind equalization approaches for time-varying andmulti-path channels. The approaches employ cost reference particle filter (CRPF) as the symbol estimator, and additionally employ either least mean squares algorithm, recursive least squares algorithm, or $H{\infty}$ filter (HF) as a channel estimator such that they are jointly employed for the strategy of "Rao-Blackwellization," or equally called "mixture filtering." The novel feature of the proposed approaches is that the blind equalization is performed based on direct channel estimation with unknown noise statistics of the received signals and channel state system while the channel is not directly estimated in the conventional method, and the noise information if known in similar Kalman mixture filtering approach. Simulation results show that the proposed approaches estimate the transmitted symbols and time-varying channel very effectively, and outperform the previously proposed approach which requires the noise information in its application.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.886-890
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• 2007

Machine fault prognosis techniques have been considered profoundly in the recent time due to their profit for reducing unexpected faults or unscheduled maintenance. With those techniques, the working conditions of components, the trending of fault propagation, and the time-to-failure are forecasted precisely before they reach the failure thresholds. In this work, we propose an approach of Least Square Regression Tree (LSRT), which is an extension of the Classification and Regression Tree (CART), in association with one-step-ahead prediction of time-series forecasting technique to predict the future conditions of machines. In this technique, the number of available observations is firstly determined by using Cao's method and LSRT is employed as prognosis system in the next step. The proposed approach is evaluated by real data of low methane compressor. Furthermore, the comparison between the predicted results of CART and LSRT are carried out to prove the accuracy. The predicted results show that LSRT offers a potential for machine condition prognosis.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권1호
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• pp.72-80
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• 2016

Re-auction happens when a bid winner defaults on the payment without making second in-line purchase declaration even after determining sales permission. This is a process of selling under the court's authority. Re-auctioning contract price of real estate is largely influenced by the real estate business, real estate value, and the number of bidders. This paper is designed to establish a statistical model that deals with the number of bidders participating especially in apartment re-auctioning. For these, diverse factors are taken into consideration, including ratio of minimum sales value from the point of selling to re-auctioning, number of bidders at the time of selling, investment value of the real estate, and so forth. As an attempt to consider ambiguous and vague factors, this paper presents a comparatively vague concept of real estate and bidders as trapezoid fuzzy number. Two different methods based on the least squares estimation are applied to fuzzy regression model in this paper. The first method is the estimating method applying substitution after obtaining the estimators of regression coefficients, and the other method is to estimate directly from the estimating procedure without substitution. These methods are provided in application for re-auction data, and appropriate performance measure is also provided to compare the accuracies.

• Smart Structures and Systems
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• 제14권5호
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• pp.831-845
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• 2014

This paper proposed a discrete wavelet transform based method for time-varying physical parameter identification of shear type structures. The time-varying physical parameters are dispersed and expanded at multi-scale as profile and detail signal using discrete wavelet basis. To reduce the number of unknown quantity, the wavelet coefficients that reflect the detail signal are ignored by setting as zero value. Consequently, the time-varying parameter can be approximately estimated only using the scale coefficients that reflect the profile signal, and the identification task is transformed to an equivalent time-invariant scale coefficient estimation. The time-invariant scale coefficients can be simply estimated using regular least-squares methods, and then the original time-varying physical parameters can be reconstructed by using the identified time-invariant scale coefficients. To reduce the influence of the ill-posed problem of equation resolving caused by noise, the Tikhonov regularization method instead of regular least-squares method is used in the paper to estimate the scale coefficients. A two-story shear type frame structure with time-varying stiffness and damping are simulated to validate the effectiveness and accuracy of the proposed method. It is demonstrated that the identified time-varying stiffness is with a good accuracy, while the identified damping is sensitive to noise.

• 한국콘텐츠학회논문지
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• 제8권11호
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• pp.57-64
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• 2008

데이터 그리드는 대용량의 데이터 어플리케이션 처리를 위해 지리적으로 분산되어 있는 저장 자원을 제공한다. 대용량을 처리해야 하는 데이터 그리드 환경에서는 기존 웹 캐싱 정책이나 가상 메모리 캐쉬 교체 정책과는 다른 파일 교체 정책이 필요하다. LRU(Least Recently Used)나 LCB-K(Least Cost Beneficial based on K), EBR(Economic-based cache replacement), LVCT(Least Value-based on Caching Time) 같은 기존의 파일 교체 전략은 파일 교체를 위해 추가적인 자원이 필요하거나 미래를 예측해야한다. 본 논문은 이를 해결하기 위해 파일의 크기에 기반하여 파일 교체를 수행하는 SBR-k(Sized-based replacement-k)을 제안한다. 제안된 정책은 불확실한 미래 예측의 부담을 줄이고, 요청된 파일에 대응되는 교체 파일의 개수가 적게 하이 위해 파일 크기를 고려하였다. 성능평가 결과 캐쉬 크기가 작은 경우에 적중률이 비슷하나 캐쉬 크기가 크면 본 논문에서 제시한 정책이 우수함을 보였다.

• Journal of Information Processing Systems
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• 제13권1호
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• pp.104-113
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• 2017

In this paper, we present an approach to transmit data from the source to the destination through a minimal path (least-cost path) in a computer network of n nodes. The motivation behind our approach is to address the problem of finding a minimal path between the source and destination. From the work we have studied, we found that a Steiner tree with bounded Steiner vertices offers a good solution. A novel algorithm to construct a Steiner tree with vertices and bounded Steiner vertices is proposed in this paper. The algorithm finds a path from each source to each destination at a minimum cost and minimum number of Steiner vertices. We propose both the sequential and parallel versions. We also conducted a comparative study of sequential and parallel versions based on time complexity, which proved that parallel implementation is more efficient than sequential.

• Journal of information and communication convergence engineering
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• 제18권3호
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• pp.147-154
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• 2020

In this study, we created a system that can determine the number of vehicles entering and departing a charging station in real time for solving waiting time problems during refueling. Accordingly, we use the You Only Look Once object detection algorithm to detect and count the number of vehicles in the charging station and send the data to the Firebase Realtime Database. The result is shown using an Android application that provides a map function with the Kakao Maps API at the user interface side. Our system has an accuracy of 91% and an average response time of 3.1 s. Therefore, this system can be used by drivers to determine the availability of a charging station and to identify the charging station with the least waiting time for charging their vehicle.