• Title/Summary/Keyword: DST

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Development of the Korean Developmental Screening Test for Infants and Children (K-DST)

  • Chung, Hee Jung;Yang, Donghwa;Kim, Gun-Ha;Kim, Sung Koo;Kim, Seoung Woo;Kim, Young Key;Kim, Young Ah;Kim, Joon Sik;Kim, Jin Kyung;Kim, Cheongtag;Sung, In-Kyung;Shin, Son Moon;Oh, Kyung Ja;Yoo, Hee-Jeong;Yu, Hee Joon;Lim, Seoung-Joon;Lee, Jeehun;Jeong, Hae-Ik;Choi, Jieun;Kwon, Jeong-Yi;Eun, Baik-Lin
    • Clinical and Experimental Pediatrics
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    • v.63 no.11
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    • pp.438-446
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    • 2020
  • Background: Most developmental screening tools in Korea are adopted from foreign tests. To ensure efficient screening of infants and children in Korea, a nationwide screening tool with high reliability and validity is needed. Purpose: This study aimed to independently develop, standardize, and validate the Korean Developmental Screening Test for Infants and Children (K-DST) for screening infants and children for neurodevelopmental disorders in Korea. Methods: The standardization and validation conducted in 2012-2014 of 3,284 subjects (4-71 months of age) resulted in the first edition of the K-DST. The restandardization and revalidation performed in 2015-2016 of 3.06 million attendees of the National Health Screening Program for Infants and Children resulted in the revised K-DST. We analyzed inter-item consistency and test-retest reliability for the reliability analysis. Regarding the validation of K-DST, we examined the construct validity, sensitivity and specificity, receiver operating characteristic curve analysis, and a criterion-related validity analysis. Results: We ultimately selected 8 questions in 6 developmental domains. For most age groups and each domain, internal consistency was 0.73-0.93 and test-retest reliability was 0.77-0.88. The revised K-DST had high discriminatory ability with a sensitivity of 0.833 and specificity of 0.979. The test supported construct validity by distinguishing between normal and neurodevelopmentally delayed groups. The language and cognition domain of the revised K-DST was highly correlated with the K-Bayley Scales of Infant Development-II's Mental Age Quotient (r=0.766, 0.739), while the gross and fine motor domains were highly correlated with Motor Age Quotient (r=0.695, 0.668), respectively. The Verbal Intelligence Quotient of Korean Wechsler Preschool and Primary Scales of Intelligence was highly correlated with the K-DST cognition and language domains (r=0.701, 0.770), as was the performance intelligence quotient with the fine motor domain (r=0.700). Conclusion: The K-DST is reliable and valid, suggesting its good potential as an effective screening tool for infants and children with neurodevelopmental disorders in Korea.

Shuffled Discrete Sine Transform in Inter-Prediction Coding

  • Choi, Jun-woo;Kim, Nam-Uk;Lim, Sung-Chang;Kang, Jungwon;Kim, Hui Yong;Lee, Yung-Lyul
    • ETRI Journal
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    • v.39 no.5
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    • pp.672-682
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    • 2017
  • Video compression exploits statistical, spatial, and temporal redundancy, as well as transform and quantization. In particular, the transform in a frequency domain plays a major role in energy compaction of spatial domain data into frequency domain data. The high efficient video coding standard uses the type-II discrete cosine transform (DCT-II) and type-VII discrete sine transform (DST-VII) to improve the coding efficiency of residual data. However, the DST-VII is applied only to the Intra $4{\times}4$ residual block because it yields relatively small gains in the larger block than in the $4{\times}4$ block. In this study, after rearranging the data of the residual block, we apply the DST-VII to the inter-residual block to achieve coding gain. The rearrangement of the residual block data is similar to the arrangement of the basis vector with a the lowest frequency component of the DST-VII. Experimental results show that the proposed method reduces the luma-chroma (Cb+Cr) BD rates by approximately 0.23% to 0.22%, 0.44% to 0.58%, and 0.46% to 0.65% for the random access, low delay B, and low delay P configurations, respectively.

An ANALYTICTRANSFORM KERNEL DERIVATION METHOD FOR VERSATILE VIDEO CODING (VVC) (VVC 비디오 코덱을 위한 변환 커널 유도 방법)

  • Shrestha, Sandeep;lee, Bumshik
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2019.11a
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    • pp.246-248
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    • 2019
  • In the ongoing standardization of Versatile Video Coding (VVC), DCT-2, DST-7 and DCT-8 are accounted as the vital transform kernels. While storing all of those transform kernels, ROM memory storage is considered as the major problem. So, to deal with this scenario, a common sparse unified matrix concept is introduced in this paper. From the proposed matrix, any point transform kernels (DCT-2, DST-7, DCT-8, DST-4 and DCT-4) can be achieved after some mathematical computation. DCT-2, DST-7 and DCT-8 are the used major transform kernel in this paper.

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RECURRENT PATTERNS IN DST TIME SERIES

  • Kim, Hee-Jeong;Lee, Dae-Young;Choe, Won-Gyu
    • Journal of Astronomy and Space Sciences
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    • v.20 no.2
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    • pp.101-108
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    • 2003
  • This study reports one approach for the classification of magnetic storms into recurrent patterns. A storm event is defined as a local minimum of Dst index. The analysis of Dst index for the period of year 1957 through year 2000 has demonstrated that a large portion of the storm events can be classified into a set of recurrent patterns. In our approach, the classification is performed by seeking a categorization that minimizes thermodynamic free energy which is defined as the sum of classification errors and entropy. The error is calculated as the squared sum of the value differences between events. The classification depends on the noise parameter T that represents the strength of the intrinsic error in the observation and classification process. The classification results would be applicable in space weather forecasting.

Two-dimentsional systolic arrays for DCT/DST/DHT hardware implementation (DCT/DST/DHT 하드웨어 구현을 위한 2차원 시스톨릭 어레이)

  • 판성범;박래홍
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.10
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    • pp.11-20
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    • 1994
  • We propose two architectures using two dimensional systolic arrays for the DCT/DST/DHT. One decomposes the N-point DCT/DST/DHT into even-and odd-numbered frequency samples, and then computes them independently at the same time. In addition, the proposed architecture can be used for the IDCT/IDST/IDHT. Anogher is the modified version for the DHT/IDHT. Two proposed architectures generate outputs sequentially using real multiplications and additions. As compared to the conventional methods the proposed systolic arrays exhibit many advantages in terms of simplicity of the processing element (PE), latency, and throughput. Teh simulation results using VHDL, international standard language for hardware description, show the effectiveness of the proposed architecture.

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Parallel Computation of Elliptic Partial Differential Equation on MP-2 (MP-2에서의 타원형 편미분 방정식 병렬계산)

  • Kim, Hyoung-Joong;Lee, Yong-Ho
    • Journal of Industrial Technology
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    • v.14
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    • pp.19-28
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    • 1994
  • We can get a tridiagonal block Toeplitz linear system by the finite difference approximation of 2-D Poisson equation. To exploit the nice property of this linear equation, we transform the equation into a Lyapunov equation and apply DST (discrete sine transform) to get diagonal matrix based Lyapunov equation. DST can be performed using FFT, which enables high-speed computaion. All the computations are performed on an SIMD parallel computer, the MasPar MP-2 with 4,096 processing elements. In this paper, parallel algorithm, mapping method of the algorithm onto the MP-2, and timing results are presented.

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Single-center experience of the Korean-Developmental Screening Test for infants and children

  • Suh, Chae-Ri;Sohn, Su Ye;Kim, Gun-Ha;Jung, Seong-Kwan;Eun, Baik-Lin
    • Clinical and Experimental Pediatrics
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    • v.59 no.12
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    • pp.483-489
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    • 2016
  • Purpose: We investigated the number of test takers of the Korean-Developmental Screening Test (K-DST) in a single children's hospital within a year, according to age, referral rate, and follow-up percentage. Methods: For this study, 4,062 children who visited and received K-DST at Woorisoa Children's Hospital between January and December 2015 were enrolled. Seven test sets were used according to the Korean National Health Screening Program for infants and children in the following age groups: 4 to 6, 9 to 12, 18 to 24, 30 to 36, 42 to 48, 54 to 60, and 66 to 71 months. The results of the K-DST were categorized into 4 groups as follows: further evaluation (<-2 standard deviation [-2SD]), follow-up test (-2SD to -1SD), peer level (-1SD to 1SD), and high level (>1SD). Results: The test participants' population and follow-up population were concentrated before the age of 24 months (2,532, 62.3%). The children most commonly referred for further evaluation were those in the 30- to 41-month age group. A mismatch was found between the results of the K-DST and the additional questions. Most of the infants and children with suspicious developmental delays showed catch-up development in their follow-up tests (43 of 55, 78.2%). Conclusion: The use of K-DST should be encouraged, especially among children aged over 24 months. Multiple-choice question format for the additional questions is recommended to avoid confusion. We suggest a nationwide study to evaluate and revise the K-DST.

Dependence of Geomagnetic Storms on Their Assocatied Halo CME Parameters

  • Lee, Jae-Ok;Moon, Yong-Jae;Lee, Kyoung-Sun;Kim, Rok-Soon
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.1
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    • pp.95.2-95.2
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    • 2012
  • We have compared the geoeffective parameters of halo coronal mass ejections (CMEs) to predict geomagnetic storms. For this we consider 50 front-side full halo CMEs whose asymmetric cone model parameters and earthward direction parameter were available. For each CME we use its projected velocity (Vp), radial velocity (Vr), angle between cone axis and sky plane (${\gamma}$) from the cone model, earthward direction parameter (D), source longitude (L), and magnetic field orientation (M) of the CME source region. We make a simple and multiple linear regression analysis to find out the relationship between CME parameters and Dst index. Major results are as follows. (1) $Vr{\times}{\gamma}$ has a higher correlation coefficient (cc = 0.70) with the Dst index than the others. When we make a multiple regression of Dst and two parameters ($Vr{\times}{\gamma}$, D), the correlation coefficient increases from 0.70 to 0.77. (2) Correlation coefficients between Dst index and $Vr{\times}{\gamma}$ have different values depending on M and L. (3) Super geomagnetic storms (Dst ${\leq}$ -200 nT) only appear in the western and southward events. Our results demonstrate that not only the cone model parameters together with the earthward direction parameter improve the relationship between CME parameters and Dst index but also the source longitude and its magnetic field orientation play a significant role in predicting geomagnetic storms.

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Comparsion of Dst forecast models during intense geomagnetic storms (Dst $\leq$ -100 nT)

  • Ji, Eun-Young;Moon, Yong-Jae;Lee, Dong-Hun
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.51.2-51.2
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    • 2010
  • We have investigated 63 intense geomagnetic storms (Dst $\leq$ -100 nT) that occurred from 1998 to 2006. Using these events, we compared Dst forecast models: Burton et al. (1975), Fenrich and Luhmann (1998), O'Brien and McPherron (2000a), Wang et al. (2003), and Temerin and Li (2002, 2006) models. For comparison, we examined a linear correlation coefficient, RMS error, the difference of Dst minimum value (${\Delta}$peak), and the difference of Dst minimum time (${\Delta}$peak_time) between the observed and the predicted during geomagnetic storm period. As a result, we found that Temerin and Li model is mostly much better than other models. The model produces a linear correlation coefficient of 0.94, a RMS (Root Mean Square) error of 14.89 nT, a MAD (Mean Absolute Deviation) of ${\Delta}$peak of 12.54 nT, and a MAD of ${\Delta}$peak_time of 1.44 hour. Also, we classified storm events as five groups according to their interplanetary origin structures: 17 sMC events (IP shock and MC), 18 SH events (sheath field), 10 SH+MC events (Sheath field and MC), 8 CIR events, and 10 nonMC events (non-MC type ICME). We found that Temerin and Li model is also best for all structures. The RMS error and MAD of ${\Delta}$peak of their model depend on their associated interplanetary structures like; 19.1 nT and 16.7 nT for sMC, 12.5 nT and 7.8 nT for SH, 17.6 nT and 15.8 nT for SH+MC, 11.8 nT and 8.6 nT for CIR, and 11.9 nT and 10.5 nT for nonMC. One interesting thing is that MC-associated storms produce larger errors than the other-associated ones. Especially, the values of RMS error and MAD of ${\Delta}$peak of SH structure of Temerin and Li model are very lower than those of other models.

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