• Title/Summary/Keyword: serial-correlation

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LM Tests in Nested Serially Correlated Error Components Model with Panel Data

  • Song, Seuck-Heun;Jung, Byoung-Cheol;Myoungshic Jhun
    • Journal of the Korean Statistical Society
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    • v.30 no.4
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    • pp.541-550
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    • 2001
  • This paper considers a panel data regression model in which the disturbances follow a nested error components with serial correlation. Given this model, this paper derives several Lagrange Multiplier(LM) testis for the presence of serial correlation as well as random individual effects, nested effects, and for existence of serial correlation given random individual and nested effects.

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Trend Detection of Serially Correlated Hydrologic Series (상관성을 가진 시계열 자료의 경향성 분석에 관한 연구)

  • Oh, Je Seung;Kim, Byung Sik;Kim, Hung Soo;Seoh, Byung Ha
    • Journal of Wetlands Research
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    • v.6 no.4
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    • pp.35-43
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    • 2004
  • The non-parametric Mann-Kendall(MK) statistical test has been widely used to assess the significance of trend in hydrologic time series. The test requires sample data should be serially independent. If sample data is serially correlated, the presence of serial correlation in a time series will affect the test ability for trend analysis. So, we would like to use the modified MK test which uses the effective sample size(ESS) to eliminate the effect of serial correlation in a series. This study investigates the ability of ESS to eliminate the influence of serial correlation of MK test by Monte Carlo simulation and by real series. As the results, MK test shows the increase of trend rate as the serial correlation is increased but the modified MK test shows ESS can eliminate the serial correlation for trend analysis. Therefore we confirmed the modified MK test is a very useful tool for trend analysis.

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An Analysis on Correlations between the Factors Related to Collection Development and Collection Size of University Libraries in Korea (대학도서관의 장서개발 관련요소와 장서규모간의 관계분석)

  • 손정표
    • Journal of the Korean Society for information Management
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    • v.18 no.4
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    • pp.103-125
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    • 2001
  • The study is to analyze correlation between 12 factors related to the collection development and the collection size by the type of materials of university libraries in Korea. The results of this study are summarized as follows. The result of the correlation analysis: the number of volumes and serials titles showed the positive correlation, except 1∼2 factors by the founder, but there was no correlation between most of factors and the number of nonbok materials. And as the result of Spearman correlation analysis, the rank between correlation coefficients of the national university libraries and those of the private ones showed the coincidence of 61% only in the case of serials. The results of the bring out the significant differences only in total volumes. By the type of materials, between total volumes and added ones, most of factors revealed the higher correlation with total volumes; between added volumes and serial titles, 2∼3 factors brought out the higher correlation with serial titles; between total volumes and serial titles, most of factors showed the higher correlation with total volumes.

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Visual Analytics for Abnormal Event detection using Seasonal-Trend Decomposition and Serial-Correlation (Seasonal-Trend Decomposition과 시계열 상관관계 분석을 통한 비정상 이벤트 탐지 시각적 분석 시스템)

  • Yeon, Hanbyul;Jang, Yun
    • Journal of KIISE
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    • v.41 no.12
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    • pp.1066-1074
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    • 2014
  • In this paper, we present a visual analytics system that uses serial-correlation to detect an abnormal event in spatio-temporal data. Our approach extracts the topic-model from spatio-temporal tweets and then filters the abnormal event candidates using a seasonal-trend decomposition procedure based on Loess smoothing (STL). We re-extract the topic from the candidates, and then, we apply STL to the second candidate. Finally, we analyze the serial-correlation between the first candidates and the second candidate in order to detect abnormal events. We have used a visual analytic approach to detect the abnormal events, and therefore, the users can intuitively analyze abnormal event trends and cyclical patterns. For the case study, we have verified our visual analytics system by analyzing information related to two different events: the 'Gyeongju Mauna Resort collapse' and the 'Jindo-ferry sinking'.

Identification of Serial DNA Methylation Changes in the Blood Samples of Patients with Lung Cancer

  • Moon, Da Hye;Kwon, Sung Ok;Kim, Woo Jin;Hong, Yoonki
    • Tuberculosis and Respiratory Diseases
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    • v.82 no.2
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    • pp.126-132
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    • 2019
  • Background: The development of lung cancer results from the interaction between genetic mutations and dynamic epigenetic alterations, although the exact mechanisms are not completely understood. Changes in DNA methylation may be a promising biomarker for early detection and prognosis of lung cancer. We evaluated the serial changes in genome-wide DNA methylation patterns in blood samples of lung cancer patients. Methods: Blood samples were obtained for three consecutive years from three patients (2 years before, 1 year before, and after lung cancer detection) and from three control subjects (without lung cancer). We used the MethylationEPIC BeadChip method, which covers the 850,000 bp cytosine-phosphate-guanine (CpG) site, to conduct an epigenome-wide analysis. Significant differentially methylated regions (DMRs) were identified using p-values <0.05 in a correlation test identifying serial methylation changes and serial increase or decrease in ${\beta}$ value above 0.1 for three consecutive years. Results: We found three significant CpG sites with differentially methylated ${\beta}$ values and 7,105 CpG sites with significant correlation from control patients without lung cancer. However, there were no significant DMRs. In contrast, we found 11 significant CpG sites with differentially methylated ${\beta}$ values and 10,562 CpG sites with significant correlation from patients with lung cancer. There were two significant DMRs: cg21126229 (RNF212) and cg27098574 (BCAR1). Conclusion: This study revealed DNA methylation changes that might be implicated in lung cancer development. The DNA methylation changes may be the possible candidate target regions for the early detection and prevention of lung cancer.

Optimization based serial music generation and control (최적화 기반의 음열음악 생성 및 제어 기법)

  • Yoon, Jong-Chul;Lee, In-Kwon;Yoo, Min-Joon
    • 한국HCI학회:학술대회논문집
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    • 2008.02a
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    • pp.712-716
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    • 2008
  • In this paper, we introduce a way to generate and control the serial music using stochastical tools. A serialism, which is one of composition techniques in the 20th century modern music, is composed using uniformly distributed notes or durations. To conserve this property, we design the optimization process to generate the random numbers which can be used to compose the serial music. The optimization are designed using chi-square test and auto-correlation test. User can also apply the additional constraint to the objective function for controlling the serial music. Using the our method, we can compose and control the traditional serial music automatically.

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Effect of serial Characteristics and Library Environment on Serial Collection Decision in an Academic Health Science Library (의학분야 학술잡지 선택에 영향을 미치는 요인 연구)

  • Kim, Gi-Yeong
    • Journal of the Korean Society for information Management
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    • v.23 no.2
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    • pp.245-263
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    • 2006
  • Since the beginning of discussions on serial collection management, as budgets have waxed and waned over the ensuing decades, a number of key variables affecting selection/deselection have emerged but without the framework of a coherent and accepted theoretical model. This study is an effort to identify variables which affect the serial collection decision with special attention to selection/deselection in the context of an academic health science library. Based on results from correlation analyses and logistic regression analyses, the serial collection decision can be explained and predicted using various combinations of a reduced set of objective variables. Applications of the results to libraries are discussed, and further research is proposed.

Modeling and Analysis of High Speed Serial Links (SerDes) for Hybrid Memory Cube Systems (하이브리드 메모리 큐브 (HMC) 시스템의 고속 직렬 링크 (SerDes)를 위한 모델링 및 성능 분석)

  • Jeon, Dong-Ik;Chung, Ki-Seok
    • IEMEK Journal of Embedded Systems and Applications
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    • v.12 no.4
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    • pp.193-204
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    • 2017
  • Various 3D-stacked DRAMs have been proposed to overcome the memory wall problem. Hybrid Memory Cube (HMC) is a true 3D-stacked DRAM with stacked DRAM layers on top of a logic layer. The logic die is mainly used to implement a memory controller for HMC, and it is connected through a high speed serial link called SerDes with a host that is either a processor or another HMC. In HMC, the serial link is crucial for both performance and power consumption. Therefore, it is important that the link is configured properly so that the required performance should be satisfied while the power consumption is minimized. In this paper, we propose a HMC system model included the high speed serial link to estimate performance accurately. Since the link modeling strictly follows the link flow control mechanism defined in the HMC spec, the actual HMC performance can be estimated accurately with respect to each link configuration. Various simulations are conducted in order to deduce the correlation between the HMC performance and the link configuration with regard to memory utilization. It is confirmed that there is a strong correlation between the achievable maximum performance of HMC and the link configuration in terms of both bandwidth and latency. Therefore, it is possible to find the best link configuration when the required HMC performance is known in advance, and finding the best configuration will lead to significant power saving while the performance requirement is satisfied.

Clinical application of an intraoral scanner for serial evaluation of orthodontic tooth movement: A preliminary study

  • Yun, Dalsun;Choi, Dong-Soon;Jang, Insan;Cha, Bong-Kuen
    • The korean journal of orthodontics
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    • v.48 no.4
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    • pp.262-267
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    • 2018
  • The aim of this study was to test the clinical application of an intraoral scanner for serial evaluation of orthodontic tooth movement. The maxillary dentitions of eight patients with fixed orthodontic appliances were scanned using an intraoral scanner at the beginning of treatment (T0), and at 1 month (T1), 2 months (T2), 3 months (T3), and 4 months (T4) after T0. The serial digital models were superimposed on the palatal surface as a reference area, and the linear and angular changes of the central incisors, canines, and first molars were evaluated. The intraclass correlation coefficient and method errors showed that this method was clinically acceptable. Various types of orthodontic tooth movements, including minute movements, could be observed every month. The intraoral scanner and digital superimposition technique enabled the serial evaluation of orthodontic tooth movement without taking serial impressions and/or acquiring radiographs.

Does Coronal Knee and Ankle Alignment Affect Recurrence of the Varus Deformity after High Tibial Osteotomy?

  • Lee, O-Sung;Lee, Seung Hoon;Lee, Yong Seuk
    • Knee surgery & related research
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    • v.30 no.4
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    • pp.311-318
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    • 2018
  • Purpose: The purpose of this study was to evaluate changes in the coronal alignment of the knee and ankle joints after open wedge high tibial osteotomy (OWHTO) to determine factors related to the recurrence (R) of the varus deformity by serial analysis. Materials and Methods: Sixty-four OWHTOs were enrolled in this study. The weight bearing line (WBL) ratio, joint line convergence angle (JLCA), knee joint inclination, mechanical axis-tibial plateau angle, talar inclination (TI), and distal tibia articular angle (DTAA) were serially assessed. Serial correlation analysis between all parameters was performed. Patients were divided into R group and no recurrence (NR) group according to the WBL ratio (55%) at postoperative one year. Results: The preoperative WBL ratio showed significantly negative correlation with serial changes of JLCA, TI, and DTAA (p<0.05). The JLCA, TI, and DTAA as well as WBL ratio showed a significantly larger degree of varus alignment in the R group than in NR group at postoperative 6 weeks and 1 year after OWHTO (p<0.05). Conclusions: Sufficient correction of the WBL and restoration of the JLCA during OWHTO are essential to prevention of the R of varus deformity after the surgery because they are the only modifiable factors during surgery. Level of Evidence: IV, Case series.