• 응용통계연구
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• 제25권6호
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• pp.1019-1026
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• 2012

This paper presents a method for the identification of "edge observations" located on a boundary area constructed by a truncation variable as well as for the identification of outliers and the after fit of multivariate skew $t$-distribution(MST) to asymmetric data. The detection of edge observation is important in data analysis because it provides information on a certain critical area in observation space. The proposed method is applied to an Australian Institute of Sport(AIS) dataset that is well known for asymmetry in data space.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.487-492
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• 2008

The cooling of data centers has emerged as a significant challenge as the density of IT server increases. Server installations, along with the shrinking physical size of servers and storage systems, has resulted in high power density and high heat density. The introduction of high density enclosures into a data center creates the potential for "hot spots" within the room that the cooling system may not be able to address, since traditional designs assume relatively uniform cooling patterns within a data center. The cooling system for data center consists of a CRAC or CRAH unit and the associated air distribution system. It is the configuration of the distribution system that primarily distinguishes the different types of data center cooling systems, this is the main subject of this paper.

• Journal of Information Processing Systems
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• 제17권3호
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• pp.441-452
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• 2021

Federated learning provides an efficient integrated model for distributed data, allowing the local training of different data. Meanwhile, the goal of multi-task learning is to simultaneously establish models for multiple related tasks, and to obtain the underlying main structure. However, traditional federated multi-task learning models not only have strict requirements for the data distribution, but also demand large amounts of calculation and have slow convergence, which hindered their promotion in many fields. In our work, we apply the rank constraint on weight vectors of the multi-task learning model to adaptively adjust the task's similarity learning, according to the distribution of federal node data. The proposed model has a general framework for solving optimal solutions, which can be used to deal with various data types. Experiments show that our model has achieved the best results in different dataset. Notably, our model can still obtain stable results in datasets with large distribution differences. In addition, compared with traditional federated multi-task learning models, our algorithm is able to converge on a local optimal solution within limited training iterations.

• 상하수도학회지
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• 제37권6호
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• pp.383-394
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• 2023

Currently, there is no definitive regulation for the appropriate frequency of data sampling in water distribution networks, yet it plays a crucial role in the efficient operation of these systems. This study proposes a new methodology for determining the optimal frequency of data acquisition in water distribution networks. Based on the decomposition of signals using harmonic series, this methodology has been validated using actual data from water distribution networks. By analyzing 12 types of data collected from two points, it was demonstrated that utilizing the factors and cumulative periodograms of harmonic series enables similar accuracy at lower data acquisition frequencies compared to the original signals. Type your abstract here.

• Communications for Statistical Applications and Methods
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• 제25권3호
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• pp.245-261
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• 2018

Attempts have been made to define new classes of distributions that provide more flexibility for modelling skewed data in practice. In this work we define a new extension of the generalized gamma distribution (Stacy, The Annals of Mathematical Statistics, 33, 1187-1192, 1962) for Marshall-Olkin generalized gamma (MOGG) distribution, based on the generator pioneered by Marshall and Olkin (Biometrika, 84, 641-652, 1997). This new lifetime model is very flexible including twenty one special models. The main advantage of the new family relies on the fact that practitioners will have a quite flexible distribution to fit real data from several fields, such as engineering, hydrology and survival analysis. Further, we also define a MOGG mixture model, a modification of the MOGG distribution for analyzing lifetime data in presence of cure fraction. This proposed model can be seen as a model of competing causes, where the parameter associated with the Marshall-Olkin distribution controls the activation mechanism of the latent risks (Cooner et al., Statistical Methods in Medical Research, 15, 307-324, 2006). The asymptotic properties of the maximum likelihood estimation approach of the parameters of the model are evaluated by means of simulation studies. The proposed distribution is fitted to two real data sets, one arising from measuring the strength of fibers and the other on melanoma data.

• 융합보안논문지
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• 제20권4호
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• pp.71-80
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• 2020

사이버전 훈련 시스템에 현실감 있는 트래픽을 제공하기 위해서는 사전에 트래픽 유통계획 작성과 정상/위협 데이터셋을 이용한 훈련데이터셋 생성이 필요하다. 본 논문은 사이버전 훈련 시스템에 실제 환경과 같은 배경 트래픽을 제공하기 위한 트래픽 유통계획 저작과 훈련데이터셋을 생성하는 방법의 설계와 구현 결과를 제시한다. 트래픽 유통계획은 트래픽을 유통할 훈련 환경의 네트워크 토폴로지와 실제 및 모의환경에서 수집한 트래픽 속성 정보를 이용하여 저작하는 방법을 제안한다. 트래픽 유통계획에 따라 훈련데이터셋을 생성하는 방법은 단위트래픽을 이용하는 방법과 프로토콜의 비율을 이용하는 혼합트래픽 양상 방법을 제안한다. 구현한 도구를 이용하여 트래픽 유통계획을 저작하고, 유통계획에 따른 훈련데이터셋 생성결과를 확인하였다.

• Journal of the Korean Data and Information Science Society
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• 제18권2호
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• pp.543-552
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• 2007

We consider estimation of the right-tail probability in a half-triangle distribution, and also consider inference on reliability, and derive the k-th moment of ratio of two independent half-triangle distributions with different supports. As we define a skew-symmetric random variable from a symmetric triangle distribution about origin, we derive its k-th moment.

• Journal of the Korean Data and Information Science Society
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• 제10권1호
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• pp.67-77
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• 1999

For a orientation-shift model supported on the unit sphere, Euler angles are the conventional measure to parametrize orientation-shifts. The essential role which is played by rotationally symmetry of an underlying distribution is reviewed. In this paper we propose the inference procedure based on Euler angles for the rotationally symmetric spherical distribution. The likelihood ratio test(LRT) based on the Euler angles is worked out. The asymptotic distribution of the test under the null hypotheses and certain contiguous alternatives is obtained.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권2호
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• pp.211-215
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• 2008

통신 미들웨어는 응용프로그램에서 담당하던 데이타 교환을 대행한다. 여러 가지 통신 미들웨어 기술이 있지만, 다양한 디바이스들이 동적으로 네트워크 도메인을 형성하고 동일한 타입의 데이타를 빈번히 주고받는 통신환경에서는 데이타 중심 발간/구독 방식의 데이타 교환이 적합하며 OMG의 DDS(Data Distribution Service)에서 이러한 방식을 표준으로 채택하였다. 본 연구에서는 OMG의 DDS 표준 규격을 준수하고 시스템 관리 자동화가 가능한 데이타 분배 서비스 시스템인 ReTiCoM을 설계하고, 그 성능을 유사한 미들웨어인 JMS와 비교 분석하였다.

• 대한토목학회논문집
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• 제26권4D호
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• pp.661-670
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• 2006

건설 공정계획을 수립함에 있어 시뮬레이션의 제한적인 활용은 시뮬레이션 관련 데이터의 수집과 모델 구축의 어려움에 그 원인을 두고 있다. 본 연구에서는 시뮬레이션 관련 데이터 수집과 분석을 통하여 건설 장비 운영 특성 데이터 축적과 데이터 분포 특성 분석 방법론을 제시하였다. 실제 현장에서 측정한 건설 장비 운영 데이터를 확률 통계적 기법을 적용하여 데이터의 분포 특성을 분석하였으며, 이러한 데이터 축적 및 데이터베이스(DB)화는 시뮬레이션 입력 데이터의 지원과 건설 장비 운영 계획에 다시 사용되어 건설 관련 정보의 효율적 활용이 가능하다.