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An Efficient Implementation of LDPC Decoder with Partial Parallel Algorithm for DVB-S2 System
Suksoon Choi1,Minhyuk Kim,Jongtae Bae,Taedoo Park,Namsoo Kim,Jiwon Jung 대한전자공학회 2008 ITC-CSCC :International Technical Conference on Ci Vol.2008 No.7
In this paper, we investigate the encoding and decoding method of the irregular LDPC (Low Density Parity Check) codes that offer diverse coding rates from 1/2 to 9/10 defined in the Digital Video Broadcasting (DVB-S2) standard. We study the efficient memory assignment and the implementing method in the LDPC codes.
Jiwon Choi(Jiwon Choi),Keesin Jeong(Keesin Jeong),Haiyoung Jung(Haiyoung Jung) 한국화재소방학회 2022 International Journal of Fire Science and Engineer Vol.36 No.4
Dust and fine dust exist in various forms and can lead to various problems such as dust explosion and air pollution. To reduce them, recently, research on electrospray electric precipitation, among various dust collection methods, has been actively conducted. In this study, comparative analysis experiments were performed on microdroplet generation characteristics for direct and indirect charging methods of electrospray electric precipitation. A visualization device was fabricated to generate microdroplets, and microdroplets were photographed with a high-magnification camera according to each charging method. The size and number of microdroplets were then analyzed via ImageJ software.
Young Children’s Metacognition Expressed during Coding Play
Han Jiwon(Jiwon Han),Choi Younchul(Younchul Choi) The Pacific Early Childhood Education Research Ass 2023 Asia-Pacific journal of research in early childhoo Vol.17 No.3
The purpose of this study is to explore young children’s metacognition expressed during coding play. The children participating in this study consisted of 13 five-year children(6 males and 7 females) at H Kindergarten in S City. Various data, such as observation records, researcher’s own journals, and informal consultation meeting records were collected and analyzed. The results of this study are as follows: First, metacognitive planning can be further activated in coding play while children create their own meaning through judgment and selection. Second, children are engaged in monitoring the degree to which performance is progressing towards a desired goal. Third, metacognitive control actively appeared in coding play while children changed ways of conducting tasks. Fourth, children review task performance and evaluate the quality of performance in coding play. The results of this study are expected to help understand how young children’s metacognition appears in coding play, and further reveal the educational value of coding play that helps young children activate their metacognition.
( Jiwon Choi ),( Myoung Kyu Lee ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1
Background: Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are important causes of hospital admission and mortality. We evaluated CAT score and mMRC as prognostic factors associated the readmission or mortality due to re-exacerbation of COPD within 6 months. Methods: Prospective study was enrolled 314 patients who hospitalized with severe AECOPD. We collected demographic, clinical and laboratory .findings at admission. Lung function was evaluated using the COPD assessment test (CAT) questionnaire, the modi- fied Medical Research Council (mMRC) dyspnea scale, and spirometry in the stable state. Results: The mean age was 72.2 ± 9.4 years (76.4% of male), and the rate of readmission within 6 months was 50.0% and 180-day-mortality rate was 18.2%.The baseline CAT score categorized into four groups (0-9, 10-19, 20-29, and 30-40) and mMRC was also categorized into 4 groups (0-1, 2, 3 and 4) as a dyspnea scale. The 180-day-mortality according CAT score was 0/11 (0%) 9/102 (8.8%), 30/146 (20.5%) and 18/55 (32.7%) and re-admission was 0/11 (0%), 20/102 (19.6%), 91/146 (62.3%) and 46/55 (83.6%) respectively. The 180-day-mortality according mMRC was 1/29 (3.4%), 25/158 (15.8%), 19/100 (19.0%) and 12/27 (44.4%) and re-admission was 2/29 (6.9%), 63/158 (39.9%), 70/100 (70.0%) and 22/27 (81.5%) respectively. CAT score (P < 0.001) and mMRC (P < 0.001) were significantly associated with both 180.day-mortality and readmission due to severe AECOPD in multivariate analysis and showed a good accuracy to predict the mortality and readmission due to severe AECOPD. Conclusions: Our study suggested that CAT and mMRC could be valid prognostic factors to identify patients at further risk of exacerbation and mortality so can be used in clinical practice for more appropriate management and follow up on patient with severe AECOPD.
Automated Space Classification for Network Robots in Ubiquitous Environments
Choi, Jiwon,Cho, Seoungjae,Chu, Phuong,Vu, Hoang,Um, Kyhyun,Cho, Kyungeun Hindawi Limited 2015 Journal of sensors Vol.2015 No.-
<P>Network robots provide services to users in smart spaces while being connected to ubiquitous instruments through wireless networks in ubiquitous environments. For more effective behavior planning of network robots, it is necessary to reduce the state space by recognizing a smart space as a set of spaces. This paper proposes a space classification algorithm based on automatic graph generation and naive Bayes classification. The proposed algorithm first filters spaces in order of priority using automatically generated graphs, thereby minimizing the number of tasks that need to be predefined by a human. The filtered spaces then induce the final space classification result using naive Bayes space classification. The results of experiments conducted using virtual agents in virtual environments indicate that the performance of the proposed algorithm is better than that of conventional naive Bayes space classification.</P>
Initial Positioning of a Smart Actuator Using Dual Absolute Encoders
Jiwon Choi,Chang-Hyuk Lee,Young-bong Bang 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10
In order to precisely control motor positions, most motor systems use an encoder as the feedback sensor. In the case of a simple system, an incremental encoder and limit switches are used for initial position setting. However, this system loses the current position data when the power goes down and the final position is changed due to an external force. For this reason, absolute encoders are used in full-fledged systems and to facilitate the best performance, a high-resolution absolute encoder should be directly attached at the output axis. However high-resolution absolute encoders are usually large and expensive, and in many cases, it is structurally difficult to directly install the absolute encoder to the output axis. An alternative to this direct sensing of the output angle is a multiturn absolute encoder, which is attached to the motor shaft. However, the multiturn absolute encoder also loses its position data when the backup battery runs out and an external force is applied. In this paper, we therefore suggest a dual absolute encoder system, in which one absolute encoder is attached to the motor shaft and the other low-resolution absolute encoder is attached to the output shaft of the harmonic drive speed reducer (the output shaft of a smart actuator). The required conditions for the errorless operation of this dual encoder system are derived and verified by simulations and experiments.
Choi, Yeun Seoung,Lim, Jung Soo,Kwon, Woocheol,Jung, Soon-Hee,Park, Il Hwan,Lee, Myoung Kyu,Lee, Won Yeon,Yong, Suk Joong,Lee, Seok Jeong,Jung, Ye-Ryung,Choi, Jiwon,Choi, Ji Sun,Jeong, Joon Taek,Yoo, The Korean Academy of Tuberculosis and Respiratory 2015 Tuberculosis and Respiratory Diseases Vol.78 No.4
Pulmonary Langerhans cell histiocytosis is an uncommon diffuse cystic lung disease in adults. In rare cases, it can involve extrapulmonary organs and lead to endocrine abnormalities such as central diabetes insipidus. A 42-year-old man presented with polyphagia and polydipsia, as well as a dry cough and dyspnea on exertion. Magnetic resonance imaging of the hypothalamic-pituitary system failed to show the posterior pituitary, which is a typical finding in patients with central diabetes insipidus. This condition was confirmed by a water deprivation test, and the patient was also found to have type 2 diabetes mellitus. Computed tomographic scanning of the lungs revealed multiple, irregularly shaped cystic lesions and small nodules bilaterally, with sparing of the costophrenic angles. Lung biopsy through video-assisted thoracoscopic surgery revealed pulmonary Langerhans cell histiocytosis. On a follow-up visit, only 1 year after the patient had quit smoking, clinical and radiological improvement was significant. Here, we report an uncommon case of pulmonary Langerhans cell histiocytosis that simultaneously presented with diabetes insipidus and diabetes mellitus.
3',4'-Dihydroxyl Groups in Luteolin are Important for Its Inhibitory Activities against ADAMTS-4
Jiwon Choi,정기웅,Jin-Kyoung Kim,Byung Ha Chang,Jee-Young Lee,김양미 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.9
A disintegrin and metalloprotease with thrombospondin domains (ADAMTS) are a member of peptidase and involved in processing of von Willebrand factor as well as cleavage of aggrecan, versican, brevican and neurocan. Among 19 subfamilies of human ADAMTS, ADAMTS-4 is a zinc-binding metalloprotease and is a famous therapeutic target for arthritis. It has been reported that a flavonoid luteolin shows inhibitory activity against ADMATS-4. In this study, we verified that luteolin is a potent inhibitor of ADAMTS-4 and probed the molecular basis of its action. On the basis of a docking study, we proposed a binding model between luteolin and ADAMTS-4 in which 3',4'-dihydroxyl groups in luteolin formed hydrogen bonding with ADMATS-4 and these interactions are important for its inhibitory activity against ADAMTS-4..