• The Journal of the Acoustical Society of Korea
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• v.14 no.2
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• pp.101-112
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• 1995

In order to construct a feature map-based phoneme classification system for speech recognition, two procedures are usually required. One is clustering and the other is labeling. In this paper, we present a phoneme classification system based on the Kohonen's Self-Organizing Feature Map (SOFM) for clusterer and labeler. It is known that the SOFM performs self-organizing process by which optimal local topographical mapping of the signal space and yields a reasonably high accuracy in recognition tasks. Consequently, SOFM can effectively be applied to the recognition of phonemes. Besides to improve the performance of the phoneme classification system, we propose the learning algorithm combined with the classical K-mans clustering algorithm in fine-tuning stage. In order to evaluate the performance of the proposed phoneme classification algorithm, we first use totaly 43 phonemes which construct six intra-class feature maps for six different phoneme classes. From the speaker-dependent phoneme classification tests using these six feature maps, we obtain recognition rate of $87.2\%$ and confirm that the proposed algorithm is an efficient method for improvement of recognition performance and convergence speed.

• Journal of Chest Surgery
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• v.32 no.7
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• pp.613-620
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• 1999

Background: Recently, regional or isolated organ perfusion is being studied again as a drug administration modality which is able to reduce systemic toxicity while delivering high-dose chemotherapeutic agents. This research was planned to evaluate the pharmacokinetics and long-term pathologic changes of the lung in isolated lung perfusion (ILP) with cisplatin. Material and Method: Twenty-five New Zealand white rabbits were divided into 2 groups (Group I: 10, Group II: 15). The groups were then subdivided into 2 and 3 subgroups of 5 rabbits. In group I, tissue samples of the lung and kidney, and systemic blood for platinum concentration measurement were taken 30 minutes after systemic intravenous infusion of cisplatin (5 mg/kg) and isolated lung perfusion in each 5 rabbits. In 2 subgroups of group II, lung tissues for pathologic exams were taken 30 minutes and 1 week after ILP in each 5 rabbits, which received 10% pentastarch solution only and cisplatin, respectively. In the other subgroups, lung biopsy was undertaken 4 weeks after ILP with cisplatin. Result: When cisplatin was infused via systemic vein, the platinum concentration in the lung, kidney and plasma were 1.50${\pm}$0.43 $\mu\textrm{g}$/g, 7.65${\pm}$2.49 $\mu\textrm{g}$/g, 1.19${\pm}$0.03 $\mu\textrm{g}$/ml, respectively. However, the platinum concentration in the lung was about 50 times higher (75.43${\pm}$11.47 $\mu\textrm{g}$/g) than that of intravenous infusion group, and those in the kidney and plasma were decreased (1.30${\pm}$ 0.35 $\mu\textrm{g}$/g, 0.13${\pm}$0.02 $\mu\textrm{g}$/ml) when cisplatin was introduced through ILP. Pathologic change in the treated lung with ILP was characterized by the medial hypertrophy of the pulmonary arterioles and interstitial eosinophilic infiltration, which was not dependent on cisplatin

• Tuberculosis and Respiratory Diseases
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• v.46 no.2
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• pp.251-259
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• 1999

Background: Even though the necessity for premedication has been questioned, some combinations of antisialogogues, sedatives and analgesics are usually employed by most bronchoscopists. The goal of this study was to determine whether fiberoptic bronchoscopy(FOB) could be performed safely and effectively without premedication while using a standardized topical anesthetic. Method: Eighty outpatients were randomized in a double-blind manner into group I(n=20) with 1 ml normal saline, group II(n=20) with 0.5mg of atropine, group III(n=20) with 0.5mg of atropine plus 5mg of midazolam, and group IV(n=20) with 0.5mg of atropine plus 50mg of meperidine, given intramuscularly 30 minutes before FOB as premedication Topical anesthetics administered were same in each group. Each patient was given 5ml(200mg) of 4% nebulized lidocaine and additional intratracheobronchial 2% lidocaine. Oxygen saturation, pulse rate and electrocardiogram were monitored and recorded before, during, just after and 2 minutes after FOB. Immediately after FOB, the bronchoscopists answered four questions such as ease of procedure, extent of coughing, extent of secretion, and overall impression. Before leaving bronchoscopy suite, patients completed similar questions on discomfort during procedure, and willingness to return for a repeat procedure. Results: Age, gender, baseline pulmonary function, dose of 2% lidocaine used for topical anesthesia, and duration of FOB were not significantly different. There was no statistical difference among group I to IV with regard to extent of coughing answered by bronchoscopist. But extent of secretion was significantly different between group I without atropine and group II-IV with atropine. And there was also significant difference in ease of procedure and overall impression among groups. There was no statistical difference in patient's willingness and level of discomfort among the groups. Thirteen patients(16%) showed hypoxemia(arterial oxygen saturation: <90%), and 3 patients(4%) showed significant tachyarrhythmia(heart rate: > l60/min), but the rate of complication was not statistically different among the groups. Conclusion: These results suggest that the value of premedication is questionable for outpatient FOB, although it may be necessary in excessively anxious patient.

• The Korean Journal of Nuclear Medicine
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• v.32 no.6
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• pp.490-496
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• 1998

Purpose: We evaluated brain perfusion SPECT findings of MELAS syndrome and mitochondrial myopathy in correlation with MR imaging in search of specific imaging features. Materials and Methods: Subjects were five patients (four females and one male; age range, 1 to 25 year) who presented with repeated stroke-like episodes, seizures or developmental delay or asymptomatic but had elevated lactic acid in CSF and serum. Conventional non-contrast MR imaging and Tc-99m-ethyl cysteinate dimer (ECD) brain perfusion SPECT were Performed and imaging features were analyzed. Results: MRI demonstrated increased T2 signal intensities in the affected areas of gray and white matters mainly in the parietal (4/5) and occipital lobes (4/5) and in the basal ganglia (1/5), which were not restricted to a specific vascular territory. SPECT demonstrated decreased perfusion in the corresponding regions of MRI lesions. In addition, there were perfusion defects in parietal (1 patient), temporal (2), and frontal (1) lobes and basal ganglia (1) and thalami (2). In a patient with mitochondrial myopathy who had normal MRI, decreased perfusion was noted in left parietal area and bilateral thalami. Conclusion: Tc-99m ECD SPECT imaging in patients with MELAS syndrome and mitochondrial myopathy showed hypoperfusion of parieto-occipital cortex, basal ganglia, thalamus and temporal cortex, which were not restricted to a specific vascular territory. There were no specific imaging features on SPECT. The significance of abnormal perfusion on SPECT without corresponding MR abnormalities needs to be evaluated further in larger number of patients.

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.428-437
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• 2000

Background : Five year survival rate of postoperative stage I non-small cell lung cancer(NSCLC) reaches to 66%. In the remaining one third of patients, however, cancer recurs and the overall survival of NSCLC remains dismal. To evaluate clinical and pathologic characteristics of recurred NSCLC, the patterns and factors for postoperative recurrence in patients with staged I and II NSCLC were studied. Method : A retrospective analysis was performed in 234 patients who underwent radical resection for pathologic stage I and II NSCLC. All patients who were followed up for at least one year were included in this study. Results : 1) There were 177 men and 57 women The median age was 63. The median duration of the follow up period was 732 days (range 365~1,695 days). The overall recurrence rate was 26.5%, and the recurrence occurred $358.8{\pm}239.8$ days after operation. 2) The ages of recurred NSCLC patients were higher ($63.2{\pm}8.8$ years) than those of non-recurred patients ($60.3{\pm}9.8$ years)(p=0.043). The recurrence rate was higher in stage II (46.9%) than in stage I (18.8%) NSCLC p<0.001. The size of primary lung mass was larger in recurred ($5.45{\pm}3.22\;cm$) than that of non-recurred NSCLC ($3.74{\pm}1.75\;cm$, p<0.001). Interestingly, there were no recurrent cases when the resected primary tumor was less than 2cm. 3) Distant recurrence was more frequent than locoregional recurrence (66.1% vs. 33.9%). Distant recurrence rate was higher in females and in cases of adenocarcinoma. Brain metastasis was more frequent in patients with adenocarcinoma than in those with squamous cell carcinoma (p=0.024). Conclusion: The tumor size and stage were two important factors for determining the possibility of a recurrence. Because distant brain metastasis was more frequent in patients with adenocarinoma, a prospective study should be conducted to evaluate the effectiveness of preoperative brain imaging.

• Journal of Yeungnam Medical Science
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• v.22 no.1
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• pp.72-80
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• 2005

Background: Nasopharyngeal cancer is a rare disease with a relatively poor prognosis because it tends to be diagnosed at an advanced stage. The aim of this study was to establish the clinical characteristics of nasopharyngeal cancer. Materials and Methods: The medical records of 54 patients with nasopharyngeal cancer from January 1993 to December 2002 were reviewed retrospectively. Forty one cases were male (75.9%) and thirteen were female (24.1%). The average age was of 46.9 (range 16 to 78 years) years. The majority of patients (79.6%) were diagnosed in the advanced stage. The most common complaints were a neck mass (55.5%) and the WHO type III (53.7%) was the most frequent histological type. Results: The cumulative survival rate for a 5-year period was 46.5% and the T stage, N stage, pathologic type, and clinical stage were not significantly related to the survival rate. Sixteen of 54 (31.5%) cases presented with a distant metastasis of the bone, lung, brain, spine, and liver, and six cases (11.1%) presented with a locoregional recurrence. Conclusion: TNM staging is not appropriate for predicting survival rate of nasopharyngeal carcinoma patients. Therefore, a newer staging system, which includes new factors, is needed to predict the prognosis.

• Tuberculosis and Respiratory Diseases
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• v.39 no.3
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• pp.236-241
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• 1992

Background: As well as fiberoptic bronchoscopy, chest computerized tomographic scan can now differentiate the benign from malignant causes and the obstructive from non-obstructive causes of lung collapse. This study was designed to evaluate the usefulness of chest CT scan and fiberoptic bronchoscopy in the diagnosis of middle lobe syndrome. Method: We reviewed the clinical features, roentgenographic changes, pathologic findings and bronchoscopic findings in 16 patients with middle lobe syndrome who were admitted to Severance Hospital during period of January, 1987 through January, 1992. Results: The male to female ratio was 1:1. The most common symptoms were cough and sputums. Crackle was the most common physical finding. Underlying disease was lung cancer, pulmonary tuberculosis and endobronchial tuberculosis in 3 each other, benign stenosis in 2, lung abscess, broncholithiasis, bronchial chondroma, pneumonia and nonspecific inflammation in 1 each other. Conclusion: We conclude that the combination of chest computerized tomogram and fiberoptic bronchoscopy was most desirable for the diagnosis of middle lobe syndrome.

• Clinical and Experimental Pediatrics
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• v.52 no.8
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• pp.898-903
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• 2009

Purpose : This study investigated the predictive factors for identifying infection-prone febrile infants younger than three months. Methods : We conducted a retrospective study of 167 infants younger than three months with an axillary temperature >$38^{\circ}C$ who were hospitalized between 2006 and 2008. If they met any of the following criteria, positive blood culture, CSF WBC ${\geq}11/mm^3$ or positive CSF culture, urinalysis WBC ${\geq}6$/HPF and positive urine culture, WBC ${\geq}6$/HPF on microscopic stool examination or positive stool culture, they were considered at high risk for severe infection. Infants with focal infection, respiratory infection or antibiotic administration prior to admission to the hospital were excluded. We evaluated the symptoms, physical examination findings, laboratory data, and the clinical course between the high risk and low risk groups for severe infection. Results : The high-risk group included 77(46.1%) infants, and the most common diagnosis was urinary tract infection (51.9%). Factors, such as male sex, ESR and CRP were statistically different between the two groups. But, a multilinear regression analysis for severe infection showed that male and ESR factors are significant. Conclusion : We did not find the distinguishing symptoms and laboratory findings for identifying severe infection-prone febrile infants younger than three months. However, the high-risk group was male and ESR-dominated, and these can possibly be used as predictive factors for severe infection.

• Journal of Chest Surgery
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• v.34 no.9
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• pp.698-703
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• 2001

Background: Endovascular stent-graft insertion in aortic diseases is now generally accepted as an attractive alternative treatment modality. We reviewed our clinical experiences of endovascular stent-graft insertion in thoracic aorta. Material and Method: Since 1995, we performed 8 cases of endovasclar stent-graft insertion. Preoperative diagnoses were aortic aneurysms in 4, traumatic aortic ruptures in 3, and ruptured aortic pseudoaneurysm in 1. All procedures were performed in angiography room with the guidance of fluoroscopy. The stent-graft device is a custom-made 0.35mm thickness Z-shaped stainless steel wires, intertwined with each other using polypropylene suture ligation. It is covered with expanded Dacron vascular graft. Result: All procedures were performed successfully. Follow-up studies revealed 2 minimal perigraft leakages. There was no significant leakage or graft migration. 2 patients expired due to multiple organ failure and fungal sepsis. Other survivors(6) are doing well. Conclusion: Endovascular stent-graft insertion is relatively saft and effective treatment modality in the managment of various types of aortic diseases. In may be an effective alternative in aortic diseases of great surgical risk.

• Journal of the Korean Arthroscopy Society
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• v.5 no.1
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• pp.22-26
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• 2001

Purpose : To confirm the efficacy of arthroscopic synovectomy fur the pigmented villonodular synovitis in the knee. Materials and Methods : Between October 1996 and February 2000, the arthroscopic synovectomy had been performed in six patients(six knee joints), whose diagnoses were confirmed by pathologist. All patients complained of painful swelling in involved knee and four of the six patients had trauma history. There were three male and three female patients. Average age was 35.8 years ranging from 16 to 67 years. Follow up period was average 22.7 months(range, $13\~53$ months). Results : According to arthroscopic findings, there were three localized forms and three diffuse forms. At their last follow-up examinations, all patients had improvement in pain, swelling and range of motion and there was no evidence of recurrence. Conclusion : Complete arthroscopic excision is the definitive treatment for localized pigmented villonodular synovitis and meticulous arthroscopic excision through all portals including posterior portal can be considered as a valid alternative to traditional open synovectomy for the patients with diffuse pigmented villonodular synovitis.