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Search Results: 1 - 10 of 11233 matches for " Jong-Il Park "
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A Comparative Study on Isar Imaging Algorithms for Radar Target Identification
Jong-Il Park;Kyung-Tae Kim
PIER , 2010, DOI: 10.2528/PIER10071901
Abstract: Inverse synthetic aperture radar (ISAR) images represent the two-dimensional (2-D) spatial distribution of the radar cross-section (RCS) of an object and, thus, they can be applied to the problem of target identification. The traditional approach to ISAR imaging is the range-Doppler algorithm based on the 2-D Fourier transform. However, the 2-D Fourier transform often results in poor resolution ISAR images, especially when the measured frequency bandwidth and angular region are limited. Instead of the Fourier transform, high resolution spectral estimation techniques can be adopted to improve the resolution of ISAR images. These are the autoregressive (AR) model, multiple signal classification (MUSIC), and matrix enhancement and matrix pencil MUSIC (MEMP-MUSIC). In this study, the ISAR images from these high-resolution spectral estimators, as well as the FFT approach, are identified using a recently developed identification algorithm based on the polar mapping of ISAR images. In addition, each ISAR imaging algorithm is analyzed and compared in the framework of radar target identification. The results show that the dynamic range as well as the resolution of the ISAR images plays an important role in the identification performance. Moreover, the optimum size of the subarray (i.e. covariance matrix) for MUSIC and MEMP-MUSIC in terms of target identification is experimentally derived.
Motion Compensation for Squint Mode Spotlight SAR Imaging Using Efficient 2D Interpolation
Sang-Hong Park;Jong-Il Park;Kyung-Tae Kim
PIER , 2012, DOI: 10.2528/PIER12040201
Abstract: In the squint mode airborne spotlight synthetic aperture radar system using the range migration algorithm (RMA), autofocus (AF) technique yields poor results due to the squint spreading of the point spread function (PSF) of a scatterer. Thus, two-dimensional (2D) interpolation is required to direct PSF blurring in cross-range direction, to improve the cross-range resolution ¢y and to remove the spatially-varying sidelobe. Because conventional 2D interpolation requires huge computation time and yields large computation errors, we propose an efficient 2D interpolation technique for squint-mode RMA composed of two 1D interpolations. Simulation results using the measured turbulence data show ¢y was improved considerably and PSF was successfully focused by the proposed method with a reduced computation time.
Copy Number Variation of Age-Related Macular Degeneration Relevant Genes in the Korean Population
Jung Hyun Park, Seungbok Lee, Hyeong Gon Yu, Jong-Il Kim, Jeong-Sun Seo
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0031243
Abstract: Purpose Studies that analyzed single nucleotide polymorphisms (SNP) in various genes have shown that genetic factors are strongly associated with age-related macular degeneration (AMD) susceptibility. Copy number variation (CNV) may be an additional type of genetic variation that contributes to AMD pathogenesis. This study investigated CNV in 4 AMD-relevant genes in Korean AMD patients and control subjects. Methods Four CNV candidate regions located in AMD-relevant genes (VEGFA, ARMS2/HTRA1, CFH and VLDLR), were selected based on the outcomes of our previous study which elucidated common CNVs in the Asian populations. Real-time PCR based TaqMan Copy Number Assays were performed on CNV candidates in 273 AMD patients and 257 control subjects. Results The predicted copy number (PCN, 0, 1, 2 or 3+) of each region was called using the CopyCaller program. All candidate genes except ARMS2/HTRA1 showed CNV in at least one individual, in which losses of VEGFA and VLDLR represent novel findings in the Asian population. When the frequencies of PCN were compared, only the gain in VLDLR showed significant differences between AMD patients and control subjects (p = 0.025). Comparisons of the raw copy values (RCV) revealed that 3 of 4 candidate genes showed significant differences (2.03 vs. 1.92 for VEGFA, p<0.01; 2.01 vs. 1.97 for CFH, p<0.01; 1.97 vs. 2.01, p<0.01 for ARMS2/HTRA1). Conclusion CNVs located in AMD-relevant genes may be associated with AMD susceptibility. Further investigations encompassing larger patient cohorts are needed to elucidate the role of CNV in AMD pathogenesis.
Long-Acting Injectable Antipsychotics for First-Episode Schizophrenia: The Pros and Cons
Borah Kim,Sang-Hyuk Lee,Yen Kuang Yang,Jong-Il Park,Young-Chul Chung
Schizophrenia Research and Treatment , 2012, DOI: 10.1155/2012/560836
Abstract: Clinical and psychosocial deterioration associated with schizophrenia occurs within the first few years following the onset of the illness. Therefore, to improve the long-term prognosis, it is important to provide schizophrenia patients with intensive treatment following their first episode. Relapse is highly associated with partial medication adherence or nonadherence in patients with first-episode schizophrenia. Recent studies suggest that long-acting injectable (LAI) antipsychotics compared with oral antipsychotics are more effective for medication adherence and relapse prevention. Moreover, some clinical guidelines for the treatment of schizophrenia suggested that LAI antipsychotics should be considered when patients are nonadherent “at any stage.” Decreased compliance is a common cause of relapse during the initial stages of the disease. Therefore, LAI antipsychotics should be highly considered when treating patients with first-episode schizophrenia. In the present paper, clinical trial data and current guidelines on the use of LAI antipsychotics for first-episode schizophrenia are discussed as well as the pros and cons of this treatment option.
Long-Acting Injectable Antipsychotics for First-Episode Schizophrenia: The Pros and Cons
Borah Kim,Sang-Hyuk Lee,Yen Kuang Yang,Jong-Il Park,Young-Chul Chung
Schizophrenia Research and Treatment , 2012, DOI: 10.1155/2012/560836
Abstract: Clinical and psychosocial deterioration associated with schizophrenia occurs within the first few years following the onset of the illness. Therefore, to improve the long-term prognosis, it is important to provide schizophrenia patients with intensive treatment following their first episode. Relapse is highly associated with partial medication adherence or nonadherence in patients with first-episode schizophrenia. Recent studies suggest that long-acting injectable (LAI) antipsychotics compared with oral antipsychotics are more effective for medication adherence and relapse prevention. Moreover, some clinical guidelines for the treatment of schizophrenia suggested that LAI antipsychotics should be considered when patients are nonadherent “at any stage.” Decreased compliance is a common cause of relapse during the initial stages of the disease. Therefore, LAI antipsychotics should be highly considered when treating patients with first-episode schizophrenia. In the present paper, clinical trial data and current guidelines on the use of LAI antipsychotics for first-episode schizophrenia are discussed as well as the pros and cons of this treatment option. 1. Introduction Schizophrenia is a chronic disorder characterized by periods of illness alternating with periods of full or partial remission. Previous studies [1, 2] suggest that schizophrenia is a neurodegenerative disease associated with frequent relapses. This alternating nature of the illness causes neurotoxicity in the brain, thereby resulting in structural abnormalities, including ventricular enlargement and cortical atrophy. Recent evidence further suggests that progressive structural changes in the brain occur within the initial years following a diagnosis [3–5]. Moreover, with each subsequent relapse after the first episode, it usually takes longer time to reach remission [6]. The primary clinical and psychosocial deterioration associated with schizophrenia occurs within the first 5 years following the onset of the illness, called the critical period [7, 8]. Therefore, it is important to provide intensive biopsychosocial interventions during the critical period in an effort to improve the long-term prognosis. The primary goal of treatment during the critical period is to prevent a subsequent relapse and to restore socio-occupational functioning to the premorbid level. The relapse rate in patients with first-episode schizophrenia is relatively low during the first year of the illness but substantially rises to rates of 53.7% and 74%–81.9% after 2 and 5 years, respectively [9, 10]. The most common
A genome-wide Asian genetic map and ethnic comparison: The GENDISCAN study
Young Ju, Hansoo Park, Mi Kyeong Lee, Jong-Il Kim, Joohon Sung, Sung-Il Cho, Jeong-Sun Seo
BMC Genomics , 2008, DOI: 10.1186/1471-2164-9-554
Abstract: We constructed the genetic map of a Mongolian population in Asia with CRIMAP software. This new map, called the GENDISCAN map, is based on genotype data collected from 1026 individuals of 73 large Mongolian families, and includes 1790 total and 1500 observable meioses. The GENDISCAN map provides sex-averaged and sex-specific genetic positions of 1039 microsatellite markers in Kosambi centimorgans (cM) with physical positions. We also determined 95% confidence intervals of genetic distances of the adjacent marker intervals.Genetic lengths of the whole genome, chromosomes and adjacent marker intervals are compared with those of Rutgers Map v.2, which was constructed based on Caucasian populations (Centre d'Etudes du Polymorphisme Humain (CEPH) and Icelandic families) by mapping methods identical to those of the GENDISCAN map, CRIMAP software and the Kosambi map function. Mongolians showed approximately 1.9 fewer recombinations per meiosis than Caucasians. As a result, genetic lengths of the whole genome and chromosomes of the GENDISCAN map are shorter than those of Rutgers Map v.2. Thirty-eight marker intervals differed significantly between the Mongolian and Caucasian genetic maps.The new GENDISCAN map is applicable to the genetic study of Asian populations. Differences in the genetic distances between the GENDISCAN and Caucasian maps could facilitate elucidation of genomic variations between different ethnic groups.Genetic maps provide specific positions of genetic markers, which are required for performing genetic studies. Linkage analyses, which aim to identify genetic loci related to human phenotypes and complex diseases, have been performed with Caucasian genetic maps even in Asian populations, because no comprehensive Asian genetic maps with dense markers have yet been introduced. Since multipoint methods are frequently used in linkage analyses, it is important to use correct maps for the population being studied [1].Distance between adjacent genetic markers in
Targeted Next-Generation Sequencing at Copy-Number Breakpoints for Personalized Analysis of Rearranged Ends in Solid Tumors
Hyun-Kyoung Kim, Won Cheol Park, Kwang Man Lee, Hai-Li Hwang, Seong-Yeol Park, Sungbin Sorn, Vishal Chandra, Kwang Gi Kim, Woong-Bae Yoon, Joon Seol Bae, Hyoung Doo Shin, Jong-Yeon Shin, Ju-Young Seoh, Jong-Il Kim, Kyeong-Man Hong
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100089
Abstract: Background The concept of the utilization of rearranged ends for development of personalized biomarkers has attracted much attention owing to its clinical applicability. Although targeted next-generation sequencing (NGS) for recurrent rearrangements has been successful in hematologic malignancies, its application to solid tumors is problematic due to the paucity of recurrent translocations. However, copy-number breakpoints (CNBs), which are abundant in solid tumors, can be utilized for identification of rearranged ends. Method As a proof of concept, we performed targeted next-generation sequencing at copy-number breakpoints (TNGS-CNB) in nine colon cancer cases including seven primary cancers and two cell lines, COLO205 and SW620. For deduction of CNBs, we developed a novel competitive single-nucleotide polymorphism (cSNP) microarray method entailing CNB-region refinement by competitor DNA. Result Using TNGS-CNB, 19 specific rearrangements out of 91 CNBs (20.9%) were identified, and two polymerase chain reaction (PCR)-amplifiable rearrangements were obtained in six cases (66.7%). And significantly, TNGS-CNB, with its high positive identification rate (82.6%) of PCR-amplifiable rearrangements at candidate sites (19/23), just from filtering of aligned sequences, requires little effort for validation. Conclusion Our results indicate that TNGS-CNB, with its utility for identification of rearrangements in solid tumors, can be successfully applied in the clinical laboratory for cancer-relapse and therapy-response monitoring.
The Function of Heterodimeric AP-1 Comprised of c-Jun and c-Fos in Activin Mediated Spemann Organizer Gene Expression
Sung-Young Lee, Jaeho Yoon, Hyun-Shik Lee, Yoo-Seok Hwang, Sang-Wook Cha, Chul-Ho Jeong, Jong-Il Kim, Jae-Bong Park, Jae-Yong Lee, SungChan Kim, Mae Ja Park, Zigang Dong, Jaebong Kim
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0021796
Abstract: Background Activator protein-1 (AP-1) is a mediator of BMP or FGF signaling during Xenopus embryogenesis. However, specific role of AP-1 in activin signaling has not been elucidated during vertebrate development. Methodology/Principal Findings We provide new evidence showing that overexpression of heterodimeric AP-1 comprised of c-jun and c-fos (AP-1c-Jun/c-Fos) induces the expression of BMP-antagonizing organizer genes (noggin, chordin and goosecoid) that were normally expressed by high dose of activin. AP-1c-Jun/c-Fos enhanced the promoter activities of organizer genes but reduced that of PV.1, a BMP4-response gene. A loss of function study clearly demonstrated that AP-1c-Jun/c-Fos is required for the activin-induced organizer and neural gene expression. Moreover, physical interaction of AP-1c-Jun/c-Fos and Smad3 cooperatively enhanced the transcriptional activity of goosecoid via direct binding on this promoter. Interestingly, Smad3 mutants at c-Jun binding site failed in regulation of organizer genes, indicating that these physical interactions are specifically necessary for the expression of organizer genes. Conclusions/Significance AP-1c-Jun/c-Fos plays a specific role in organizer gene expression in downstream of activin signal during early Xenopus embryogenesis.
The first Irish genome and ways of improving sequence accuracy
Young Seok Ju, Yun Joo Yoo, Jong-Il Kim, Jeong-Sun Seo
Genome Biology , 2010, DOI: 10.1186/gb-2010-11-9-132
Abstract: See research article: http://genomebiology.com/2010/11/9/R91 webciteIn the past 10 years, numerous human genomic variants have been discovered and catalogued, mostly through the efforts of the International HapMap project and personal genome studies [1]. Information on human genomic variants may serve as a valuable resource for developing personalized medicine because some of these variants could potentially predispose humans to complex diseases. The 2009 version (version 130) of the dbSNP database included approximately 13.9 million (13.9 M) single nucleotide polymorphisms (SNPs) and 4.5 M small insertions and deletions (indels). However, many issues need to be addressed before personalized medicine becomes a reality. These include an understanding of: the kind and number of variants that exist in the entire human genome; the number of populations and individuals needed to detect most, if not all, human genomic variants with efficiency and accuracy; the frequency of common and rare variants in an individual genome; and finally the number of variants that influence human diseases.Recent advancements in next-generation sequencing technology have dramatically decreased both the cost and the time required for sequencing [1]. Consequently, in the past few years, sequencing of individual genomes (personal genomes) has gained in popularity. Currently, whole-genome sequencing is thought to be the best way to detect human genomic variations because it could detect novel variants [2]. Excluding cancer genomes, so far at least 15 personal genomes have been sequenced and analyzed using various platforms (Figure 1). In this issue of Genome Biology, Tong and colleagues [3] present data on the first whole-genome sequence of an Irish person using the Illumina Genome Analyzer platform. As the authors [3] suggest, the Irish population could be a good candidate for genomic studies as it is isolated and located in the western fringes of Europe, and thus may possess many polymorphisms
Targeted Sequencing of Cancer-Related Genes in Colorectal Cancer Using Next-Generation Sequencing
Sae-Won Han, Hwang-Phill Kim, Jong-Yeon Shin, Eun-Goo Jeong, Won-Chul Lee, Kyung-Hun Lee, Jae-Kyung Won, Tae-Yong Kim, Do-Youn Oh, Seock-Ah Im, Yung-Jue Bang, Seung-Yong Jeong, Kyu Joo Park, Jae-Gahb Park, Gyeong Hoon Kang, Jeong-Sun Seo, Jong-Il Kim, Tae-You Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064271
Abstract: Recent advance in sequencing technology has enabled comprehensive profiling of genetic alterations in cancer. We have established a targeted sequencing platform using next-generation sequencing (NGS) technology for clinical use, which can provide mutation and copy number variation data. NGS was performed with paired-end library enriched with exons of 183 cancer-related genes. Normal and tumor tissue pairs of 60 colorectal adenocarcinomas were used to test feasibility. Somatic mutation and copy number alteration were analyzed. A total of 526 somatic non-synonymous sequence variations were found in 113 genes. Among these, 278 single nucleotide variations were 232 different somatic point mutations. 216 SNV were 79 known single nucleotide polymorphisms in the dbSNP. 32 indels were 28 different indel mutations. Median number of mutated gene per tumor was 4 (range 0–23). Copy number gain (>X2 fold) was found in 65 genes in 40 patients, whereas copy number loss (
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