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Search Results: 1 - 10 of 1777 matches for " Byoung Kuk Jang "
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A hybrid decision support model to discover informative knowledge in diagnosing acute appendicitis
Chang Sik Son, Byoung Kuk Jang, Suk Tae Seo, Min Soo Kim, Yoon Nyun Kim
BMC Medical Informatics and Decision Making , 2012, DOI: 10.1186/1472-6947-12-17
Abstract: We enrolled 326 patients who attended an emergency medical center complaining mainly of acute abdominal pain. Statistical analysis approaches were used as a feature selection process in the design of decision support models, including the Chi-square test, Fisher's exact test, the Mann-Whitney U-test (p < 0.01), and Wald forward logistic regression (entry and removal criteria of 0.01 and 0.05, or 0.05 and 0.10, respectively). The final decision support models were constructed using the C5.0 decision tree algorithm of Clementine 12.0 after pre-processing.Of 55 variables, two subsets were found to be indispensable for early diagnostic knowledge discovery in acute appendicitis. The two subsets were as follows: (1) lymphocytes, urine glucose, total bilirubin, total amylase, chloride, red blood cell, neutrophils, eosinophils, white blood cell, complaints, basophils, glucose, monocytes, activated partial thromboplastin time, urine ketone, and direct bilirubin in the univariate analysis-based model; and (2) neutrophils, complaints, total bilirubin, urine glucose, and lipase in the multivariate analysis-based model. The experimental results showed that the model with univariate analysis (80.2%, 82.4%, 78.3%, 76.8%, 83.5%, and 80.3%) outperformed models using multivariate analysis (71.6%, 69.3%, 73.7%, 69.7%, 73.3%, and 71.5% with entry and removal criteria of 0.01 and 0.05; 73.5%, 66.0%, 80.0%, 74.3%, 72.9%, and 73.0% with entry and removal criteria of 0.05 and 0.10) in terms of accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and area under ROC curve, during a 10-fold cross validation. A statistically significant difference was detected in the pairwise comparison of ROC curves (p < 0.01, 95% CI, 3.13-14.5; p < 0.05, 95% CI, 1.54-13.1). The larger induced decision model was more effective for identifying acute appendicitis in patients with acute abdominal pain, whereas the smaller induced decision tree was less accurate with the test
Duodenal variceal bleeding after balloon-occluded retrograde transverse obliteration: Treatment with transjugular intrahepatic portosystemic shunt
Min Joung Kim,Byoung Kuk Jang,Woo Jin Chung,Jae Seok Hwang
World Journal of Gastroenterology , 2012, DOI: 10.3748/wjg.v18.i22.2877
Abstract: We report a case of duodenal varix bleeding as a long term complication of balloon occluded retrograde transvenous obliteration (BRTO), which was successfully treated with a transjugular intrahepatic portosystemic shunt (TIPS). A 57-year-old man was admitted to the emergency room suffering from melena. He had undergone BRTO to treat gastric varix bleeding 5 mo before admission. Endoscopy and a computed tomography (CT) scan showed complete obliteration of the gastric varix, but the nodular varices in the second portion of the duodenum expanded after BRTO, and spurting blood was seen. TIPS was performed for treatment of duodenal variceal bleeding, because attempts at endoscopic varix ligation were unsuccessful. The postoperative course was uneventful and the patient was discharged without complications. A follow up CT scan obtained 21 mo after TIPS revealed a patent TIPS tract and complete obliteration of duodenal varices, but multinodular hepatocellular carcinoma had developed. He died of hepatic failure 28 mo after TIPS.
The Autophagy-Related Marker LC3 Can Predict Prognosis in Human Hepatocellular Carcinoma
Yoo Jin Lee, Yu Jin Ha, Yu Na Kang, Koo Jeong Kang, Jae Seok Hwang, Woo Jin Chung, Kwang Bum Cho, Kyung Sik Park, Eun Soo Kim, Hye-Young Seo, Mi-Kyung Kim, Keun-Gyu Park, Byoung Kuk Jang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0081540
Abstract: Background Defects of autophagy and endoplasmic reticulum (ER) stress are related to many diseases and tumors. However, only a few studies have examined hepatocellular carcinoma (HCC) as related to these processes. Therefore, in this study, we investigated the expression and extent of autophagy and ER stress-related markers in HCC and their influence on clinical characteristics and prognosis for each protein. Methodology The expression of autophagy-related markers (LC3 and Beclin-1) and ER stress-related markers (GRP78 and CHOP) was analyzed by immunohistochemistry on tissues from completely resected specimens of 190 HCC patients. Their influence on clinicopathologic features and prognosis were evaluated using the chi-square test and Kaplan-Meier analysis. Correlations of each protein were determined by Spearman's correlation analysis. Principal Findings LC3 expression was not correlated with TNM, BCLC stage, or Edmonson-Steiner grading, whereas it was correlated with longer overall survival (OS) (p = 0.039) and tended to be related with longer time to recurrence (TTR) (p=0.068) although it did not show statistical significance. Multivariate analysis indicated that LC3 expression was a significantly independent prognostic factor of OS (HR, 0.42; 95% CI, 0.22-0.80; p-value=0.009) and TTR (HR, 0.54; 95% CI, 0.33–0.90; p=0.017). Expression of LC3 in advanced stages of TNM (III) (p=0.045) and Edmonson-Steiner Grades (III and IV) (p=0.043) was correlated with longer survival, but not in the early stages. A positive correlation was not observed between the expression of autophagy-related markers and ER stress-related markers. Conclusion Our results suggest that the expression and extent of LC3 might be a strong prognostic factor of HCC, especially in patients with surgical resection.
Distributed Sensor Network Based on RFID System for Localization of Multiple Mobile Agents  [PDF]
Byoung-Suk Choi, Joon-Woo Lee, Ju-Jang Lee, Kyoung-Taik Park
Wireless Sensor Network (WSN) , 2011, DOI: 10.4236/wsn.2011.31001
Abstract: This paper presents a distributed wireless sensor network for multiple mobile agents localization. Localization of mobile agents, such as mobile robots, humans, and moving objects, in an indoor space is essential for robot-robot interaction (RRI) and human-robot interaction (HRI). The standard localization system, which is based on sensors installed in the robot body, is not suitable for multiple agents. Therefore, the concept of sensor network, which uses wireless sensors distributed in a specified space, is used in this study. By analyzing related studies, two solutions are proposed for the localization of mobile agents including humans: a new hardware system and a new software algorithm. The first solution focuses on the architectural design of the wireless sensor network for multiple agent localization. A passive RFID system is used, and then the architecture of the sensor network is adapted to suit the target system. The second solution centers on a localization algorithm based on the sensor network. The proposed localization algorithm improves the accuracy in the multiple agent localization system. The algorithm uses the displacement conditions of the mobile agents and the recognition changes between the RFID tags and RFID reader. Through experiments using a real platform, the usefulness of the proposed system is verified.
Model Checking Implantable Cardioverter Defibrillators
Houssam Abbas,Kuk Jin Jang,Zhihao Jiang,Rahul Mangharam
Computer Science , 2015,
Abstract: Ventricular Fibrillation is a disorganized electrical excitation of the heart that results in inadequate blood flow to the body. It usually ends in death within seconds. The most common way to treat the symptoms of fibrillation is to implant a medical device, known as an Implantable Cardioverter Defibrillator (ICD), in the patient's body. Model-based verification can supply rigorous proofs of safety and efficacy. In this paper, we build a hybrid system model of the human heart+ICD closed loop, and show it to be a STORMED system, a class of o-minimal hybrid systems that admit finite bisimulations. In general, it may not be possible to compute the bisimulation. We show that approximate reachability can yield a finite simulation for STORMED systems, which improves on the existing verification procedure. In the process, we show that certain compositions respect the STORMED property. Thus it is possible to model check important formal properties of ICDs in a closed loop with the heart, such as delayed therapy, missed therapy, or inappropriately administered therapy. The results of this paper are theoretical and motivate the creation of concrete model checking procedures for STORMED systems.
Estimating the malaria transmission of Plasmodium vivax based on serodiagnosis
Kim Jung-Yeon,Kim Hyung-Hwan,Na Byoung-Kuk,Kim Yeon-Joo
Malaria Journal , 2012, DOI: 10.1186/1475-2875-11-257
Abstract: Background Plasmodium vivax re-emerged in 1993 and has now become a major public health problem during the summer season in South Korea. The aim of this study was to interpret and understand the meaning of seroepidemiological studies for developing the best malaria control programme in South Korea. Methods Blood samples were collected in Gimpo city, Paju city, Yeoncheon County, Cheorwon County and Goseong County of high risk area in South Korea. Microscopy was performed to identify patients infected with P. vivax. Antibody detection for P. vivax was performed using indirect fluorescent antibody test (IFAT). Results A total of 1,574 blood samples was collected from participants in the study areas and evaluated against three parameters: IFAT positive rate, annual antibody positive index (AAPI), and annual parasite index (API). The IFAT positive rate was 7.24% (n = 114). Of the five study areas, Gimpo had the highest IFAT positive rate (13.68%) and AAPI (4.63). Yeongcheon had the highest API in 2005 (2.06) while Gimpo had the highest API in 2006 (5.00). No correlation was observed between any of the three parameters and study sites' distance from the demilitarized zone (DMZ). Conclusions These results showed that P. vivax antibody levels could provide useful information about the prevalence of malaria in endemic areas. Furthermore, AAPI results for each year showed a closer relationship to API the following year than the API of the same year and thus could be helpful in predicting malaria transmission risks.
FATIGUE LIVES FOR INDUCTION HARDENED SHAFTS MATERIALS ACCORDING TO THE ENVIRONMENTAL TEMPERATURES
DG Lee,KC Jang,JM Kuk,IS Kim,
D.
,G.,Lee,K.,C.,Jang,J.M.,Kuk,I.S.,Kim

金属学报(英文版) , 2005,
Abstract: Rotary bending fatigue tests were carried out with two kinds of materials, S43C and S50C, using the front engine and front drive shaft (FF shaft) of vehicle. The specimens were induction hardened about 1.0mm depth from the specimen surface, and the hardness value on the surface was about HRC56-60. The tested environment temperatures were -30, 25 and 80℃ in order to look over effect of the induction hardening and the environmental temperatures on the fatigue characteristics. The fatigue limit of induction hardened specimens increased more about 45% than non-hardened specimens showing that the endurances of S43C and S50C were 98.1 and 107.9MPa in non-hardened samples, 147.1 and 156.9MPa in hardened samplesrespectably. The maximum tensile and compressive stress on the small circular defect was about +250 and -450MPa respectively when circular defect is situated on top and bottom. The fatigue life increased 80, 25 and -30℃ in order regardless of hardening. In comparison of the fatigue lives on the basis of tested result at 25℃, the fatigue lives of non-hardened specimens decreased about 35%, but that of hardened specimens decreased about only 5% at 80℃ more than at 25℃. And fatigue life of non-hardened and hardened specimens were about 110% and 120% higher at -30℃ than that of 25℃. Based on the result of stress distribution near the defect, the tensile and compressive stress repeatedly generated by load direction were the largest on the small circular defect due to the stress concentration.
Preparation and characterization of Ce-doped ZnO nanofibers by an electrospinning method
Jong-Seong Bae,Mi-Sook Won,Jang-Hee Yoon,Byoung-Seob Lee
Journal of Analytical Science & Technology , 2011,
Abstract: ZnO and Ce-doped ZnO Nanofibers on (111) Pt/SiO2/Si substrates were produced using an electrospinning technique. The as-prepared composite fibres were subjected to high-temperature calcination to produce inorganic fibers. After calcining at a temperature of 500 °C, the average diameter of the ZnO and Ce-doped ZnO nanofibers were determined to be 170 nm and 225 nm, respectively. The average grain size of the ZnO and Ce-doped ZnO nanofibers were about 50 nm and 57 nm, respectively. The microstructure, chemical bonding state and photoluminescence of the produced ZnO and Ce-doped ZnO nanofibers were investigated. The Ce-doped ZnO nanofiber can be assigned to the presence of Ce ions on substitutional sites of Zn ions and the Ce3+ state from X-ray photoelectron spectra. Compared with PL spectra of ZnO nanofibers, the peak position of the UV emission of the Ce-doped ZnO nanofibers is sharply suppressed while the green emission band is highly enhanced.
Zidovudine (AZT) and Hepatic Lipid Accumulation: Implication of Inflammation, Oxidative and Endoplasmic Reticulum Stress Mediators
Atrayee Banerjee, Mohamed A. Abdelmegeed, Sehwan Jang, Byoung-Joon Song
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0076850
Abstract: The clinical effectiveness of Zidovudine (AZT) is constrained due to its side-effects including hepatic steatosis and toxicity. However, the mechanism(s) of hepatic lipid accumulation in AZT-treated individuals is unknown. We hypothesized that AZT-mediated oxidative and endoplasmic reticulum (ER) stress may play a role in the AZT-induced hepatic lipid accumulation. AZT treatment of C57BL/6J female mice (400 mg/day/kg body weight, i.p.) for 10 consecutive days significantly increased hepatic triglyceride levels and inflammation. Markers of oxidative stress such as protein oxidation, nitration, glycation and lipid peroxidation were significantly higher in the AZT-treated mice compared to vehicle controls. Further, the levels of ER stress marker proteins like GRP78, p-PERK, and p-eIF2α were significantly elevated in AZT-treated mice. The level of nuclear SREBP-1c, a transcription factor involved in fat synthesis, was increased while significantly decreased protein levels of phospho-acetyl-CoA carboxylase, phospho-AMP kinase and PPARα as well as inactivation of 3-keto-acyl-CoA thiolase in the mitochondrial fatty acid β-oxidation pathway were observed in AZT-exposed mice compared to those in control animals. Collectively, these data suggest that elevated oxidative and ER stress plays a key role, at least partially, in lipid accumulation, inflammation and hepatotoxicity in AZT-treated mice.
A Higher Education Leadership Distance Ph.D. Program: An Assessment Using Blocher’s Ecological Learning Theory  [PDF]
Linda Kuk, James H. Banning
Creative Education (CE) , 2014, DOI: 10.4236/ce.2014.59082
Abstract:

This study utilized a case study approach to discuss the issues of distance education in the delivery of doctoral education. The case study provided abroad background to the issues of distance education graduate programs and an assessment of the case. Blocher’s (1974) Ecological Learning Theory is applied to the case to provide for analytical generalization. The results support the need for distance delivery of academic programs to consider both the content and the program’s delivery structure as important components in realizing student success.

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