• Journal of applied mathematics & informatics
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• v.30 no.5_6
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• pp.903-911
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• 2012

Let $\{u(t)\}$ and $\{u(dt)\}$ be two maximal length sequences of period $2^n-1$. The cross-correlation is defined by $C_d({\tau})=\sum{_{t=0}^{2^n-2}}(-1)^{u(t+{\tau})+v(t)$ for ${\tau}=0,1,{\cdots},2^n-2$. In this paper, we propose a new proof for finding the values and the number of occurrences of each value of $C_d({\tau})$ when $d=2^{k-2}(2^k+3)$, where $n=2k$, $k$ is a positive integer.

• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.3
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• pp.123-146
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• 1995

Several quality control schemes have been extensively compared using multivariate normal data sets simulated with various correlation structures. They include multiple univariate CUSUM charts, multivariate EWMA charts, multivariate CUSUM charts and Shewhart T$^{3}$ chart. This paper considers a new approach of the multivariate EWMA chart, in which the smoothing matrix has full elements instead of only diagonal elements. Performance of the schemes is measured by avaerage run length (ARL), coefficient of variation of run length (CVRL) and rank in order of signaling of off-target shifts in the process mean vector. The schemes are also compared by noncentrality parameter. The multiple univariate CUSUM charts are generally affected by the correlation structure. The multivariate EWMA charts provide better ARL performance. Especially, the new EWMA chart shows remarkable results in small shifts.

• Journal of the Korean Data and Information Science Society
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• v.22 no.4
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• pp.803-809
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• 2011

Properties of multivariate Shewhart and CUSUM charts for monitoring variance-covariance matrix, specially focused on correlation coefficient components, are investigated. The performances of the proposed charts based on control statistic Lawley-Hotelling $V_i$ and likelihood ratio test (LRT) statistic $TV_i$ are evaluated in terms of average run length (ARL). For monitoring correlation coe cient components of dispersion matrix, we found that CUSUM chart based on $TV_i$ gives relatively better performances and is more preferable, and the charts based on $V_i$ perform badly and are not recommended.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.711-714
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• 2008

The objective of this study is to analyze the relationship between the watershed characteristics and the critical duration of design rainfall. For estimation of critical duration, adjustment Huff's method and ILLUDAS urban runoff model were applied to urban 21 areas. Watershed characteristics such as area, channel length, channel slope, shape factor, and pipe density were used to simulate correlation analysis. The conclusions of this study are as follows; it is revealed that critical duration is influenced by the watershed characteristics such as pipe density, area and channel length. Also, multiple regression analysis using watershed characteristics is carried out and the determination coefficient of multiple regression equation shows 0.972.

• Progress in Superconductivity and Cryogenics
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• v.25 no.4
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• pp.40-44
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• 2023

For high-temperature superconducting power applications that need large current capacity, a large current conductor manufactured using multiple superconducting tape is required. Conductors being studied for large currents capacity such as CORC, TSTC, and RACC have advantages and disadvantages, and in order to use these conductors in coil form and apply them to AC power devices, research on magnetization loss occurring in superconductors due to external magnetic fields is essential. To accurately measure magnetization loss in a conductor that is twisted by stacking straight conductors like TSTC, the correlation between the measuring system and the shape of the sample must be clearly known to accurately measure the loss. In this paper, we will confirm the difference in magnetization loss measurement values according to the correlation between the length of the pickup coil and the twist pitch of the sample in CORC and TSTC shapes, and review considerations for accurate magnetization loss measurement from the results.

• The Journal of Korean Physical Therapy
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• v.12 no.1
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• pp.73-78
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• 2000

The Sit-and-Reach Test (SRT) is commonly nea to assess flexibility of the spine and length of the hamstring muscle, The purpose of this study was to describe hamstring muscle length as reflected by use of the SRT, the Hip Joint Angle (HJA) and Sack length(from C7 to S2) in children, to examine the correlation between Back length, SRT and HJA measurements and to examine gender differences. The 162 subjects were participated without known musculoskeletal and neurological impairments of their spine or lower exeremities. In the Long-silting position, the Back length, SRT and HJA measurements were obtained. A mean Back length value of 46.2cm, a mean SRT value of 29.4cm and a mean HJA of 77,0 degrees were obtained including all subjects. There was a strong correlation between the SRT and HJA measurements (r=.66). There were a difference between boys and girls in Back(p=.0019) and HJA measurements (p=.015). The results of this study suggest that measurements for the SRT and HJA were correlated than Back. The HJA measurements guide treatment more effectively than do Back length and SRT measurements.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.6
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• pp.760-768
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• 2007

Statement of problem. Conventional denture treatment for totally edentulous patients is associated with a variety of functional and psychosocial problems. The placement of implants in the anterior region of the maxilla and mandible and the fabrication of an implant-retained overdenture might solve these problems. Purpose. This study compared the marginal bone loss around the implant and evaluated the implant survival rate and complications in patients treated with overdentures retained by implants for 2 years. Material and methods. Patients who had received implant-retained overdentures using a Dolder bar at Samsung Medical Center from January 1999 to June 2005 and had participated in the annual recall programs for two years were selected for this study. A total of 18 patients and 56 $Br{\aa}ne-mark\;system^{(R)}$ implants were used, and their data were reviewed. Evaluations of the survival rate, bone quality, marginal bone loss, and complications were performed. The data on the Dolder bar length and clip length were measured. The change in marginal bone loss and the correlation between the marginal bone loss and bar length, clip length, or bone quality were investigated. Results. Implants placed in this study showed a 100% survival rate. The average annual bone loss was 1.12mm in the first year and 0.27mm in the second year in the maxilla, and 0.58mm in the first year and 0.22mm in the second year in the mandible. The marginal bone loss in the maxilla showed no significant association with those in the mandible. (P>.05). There was no significant difference in marginal bone loss around implants between the first and second year. (P>.05) There was no statistically significant relationship (P>.05) between the marginal bone loss and bone quality, clip length, or Dolder bar length. The Dolder bar length showed a high correlation with the clip length. (P<.05) Various complications were noted. Conclusion. These results confirmed the favorable outcome for patients treated with implant-retained overdentures.

• Phonetics and Speech Sciences
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• v.14 no.2
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• pp.39-54
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• 2022

This study aims to clarify the prosodic differences in speech types by examining the Korean read speech and spontaneous speech in the Korean part of the L2 Korean Speech Corpus (speech corpus for Korean as a foreign language). To this end, the articulation length, articulation speed, pause length and frequency, and the average fundamental frequency values of sentences were set as variables and analyzed via statistical methodologies (t-test, correlation analysis, and regression analysis). The results found that read speech and spontaneous speech were structurally different in the form of prosodic phrases constituting each sentence and that the prosodic elements differentiating each speech type were articulation length, pause length, and pause frequency. The statistical results show that the correlation between articulation speed and articulation length was highest in read speech, explaining that the longer a given sentence is, the faster the speaker speaks. In spontaneous speech, however, the relationship between the articulation length and the pause frequency in a sentence was high. Overall, spontaneous speech produces more pauses because short intonation phrases are continuously built to make a sentence, and as a result, the sentence gets lengthened.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.5
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• pp.313-320
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• 2020

Objectives: The aim of this study was to evaluate the relationship between masticatory muscle thickness and mandibular morphology in young Korean adults with normal occlusion and mandibular prognathism. Patients and Methods: Multidetector computed tomography (MDCT) was used to measure the masticatory muscle thickness on the right side in 100 Korean young adults (50 normal occlusion group, 50 mandibular prognathism group). Cephalometric analysis was done to measure mandibular morphology. Pearson correlation analysis was done to investigate the relationship between the masticatory muscle thickness and mandibular morphometry. Results: The four masticatory muscles showed positive correlation with intergonial width in all subjects. All muscles, except temporalis, positively correlated with height of the ramus and mandibular length. Positive correlation was also observed in all muscles, except medial pterygoid, with thickness of the ramus. In the normal occlusion group, all four masticatory muscles showed positive correlation with intergonial width and ramus thickness. Positive correlation was also observed in all muscles (except lateral pterygoid) with mandibular length. Masseter and lateral pterygoid positively correlated with height of the ramus. In the mandibular prognathism group, all masticatory muscles, except lateral pterygoid, showed positive correlation with intergonial width. The masseter muscle showed negative correlation with ANB. Conclusion: The results suggest a positive correlation of the thickness of masticatory muscles with both horizontal and vertical dimensions of the mandible. However, thickness of the masseter was found to decrease in patients with increasing severity of mandibular prognathism.

• Journal of Korean Society of Forest Science
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• v.57 no.1
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• pp.39-44
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• 1982

These studies were carried out to know the variation of needle characteristics of Abies Koreana distributed in Korea. The results are summarized as follows. The differences of needle length and number of stomata row among the population were shown one percent level, but not in each individual tree. Correlations coefficients between the D.B.H. and needle length or needle width of mother trees were not correlated all populations respectively. It was found that correlation coefficient between needle length and needle width was positive in two populations. of Mt. Doukyou and Mt. Hanla, but it was not in Mt Jiri. Correlation coefficient between needle length and the number of stomata row positive correlation in Mt. Doukyou. Correlation coefficient between needle width and the number of stomata row was shown positive in all populations, but it was not that correlation coefficient between needle width and density of serrations, and between number of stomata row and density of serrations. The coefficients of variations were shown higher density of serration than needle length, needle width and stomata row.