• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.5
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• pp.13-20
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• 2008

Although digital hearing aid algorithms have been developed to compensate hearing loss and to help hearing impaired people to communicate with others, digital hearing aid user still complain about difficulty of hearing the speech. The reason could be the quality of speech through digital hearing aid is insufficient to understand the speech caused by feedback, residual noise and etc. And another thing is masking effect among formants that makes sound quality low. In this study, we measured the masking characteristics of normal listeners and hearing impaired listeners having presbyacusis to confirm masking effect in speech itself. The experiment is composed of 5 tests; pure tone test, speech reception threshold (SRT) test, word recognition score (WRS) test, puretone masking test and speech masking test. In speech masking test, there are 25 speeches in each speech set. And log likelihood ratio (LLR) is introduced to evaluate the distortion of each speech objectively. As a result, the speech perception became lower by increasing the quantity of formant enhancement. And each enhanced speech in a speech set has statistically similar LLR, however speech perception is not. It means that acoustic masking effect rather than distortion influences speech perception. In actuality, according to the result of frequency analysis of the speech that people can not answer correctly, level difference between first formant and second formant is about 35dB, and it is similar to result of pure tone masking test(normal hearing subject:36.36dB, hearing impaired subject:32.86dB). Characteristics of masking effect is not similar between normal listeners and hearing impaired listeners. So it is required to check the characteristics of masking effect before wearing a hearing aid and to apply this characteristics to fitting.

• The Journal of the Korea Contents Association
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• v.17 no.11
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• pp.50-59
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• 2017

To evaluate the capability of integrated PET-MRI, which has recently been utilized in the clinical practices, on the diagnosis of liver cancer, its utility was assessed by $2{\times}2$ decision matrix. The numbers of abnormal and normal decisions on the liver cancer were 98 and 51 cases, respectively, upon PET-MRI scan results of the subjects, and the numbers of positive and negative decisions were 103 and 62, respectively, upon cytopathologic results. Out of the two tests, 95 cases were shown as true-positive and 3 were false positive, while 62 were true negative and 5 were false negative. Upon the results of PET-MRI test, its sensitivity, specificity, false negative rate, and false positive rate were 95.00%, 95.38%, 0.05%, and 95.15%, respectively. Therefore, it is considered to have the high potential to use the determination of the stage before the surgery, detections of recurrence and remote metastasis, assessment of uncertain remote lymph node metastasis, and so on in the diagnosis of the liver cancer, and also for the clinical utility of PET-MRI to be sufficient by integrated diagnosis and follow up scan with pathological studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.913-918
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• 2006

Patients of dyslexia have an reading disorder marked by the occurrence of semantic errors. Because there is little understanding of dyslexia in korea, we use a translation version of foreign tester for testing the patients of dyslexia. However, the foreign testers is not suitable for testing the korean patients, because language is sensitive to national culture and trait. In this paper, we propose a model of tester for dyslexia Which is used for classification and analysis of korean patients. In addition, we show some characteristics of the implemented tester by a performance study.

• Phonetics and Speech Sciences
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• v.16 no.1
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• pp.49-55
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• 2024

This study aims to develop a three-sentence speech screening test to evaluate speech development in 4-year-old children and provide standards for comparison with peers. Screening tests were conducted on 24 children each in the first and second halves of 4 years old. The screening test results showed a correlation of .7 with the existing speech disorder evaluation test results. We compared whether there was a difference between the two groups of 4-year-old in the phonological development indicators and error patterns obtained through the screening test. The developmental indicators of the children in the second half were high, but there were no statistically significant differences. The Korean Speech Sound Analysis Tool (KSAT) was used for all analyses, and the automatic analysis results and contents of the clinician's manual analysis were compared. The degree of agreement between the automatic and manual error pattern analyses was 93.63%. The significance of this study is that the standard of speech of a 4-year-old child of the speech screening test according to three sentences at the level of elicited sentences, and the applicability of the KSAT were reviewed in both clinical and research fields.

• Pediatric Infection and Vaccine
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• v.11 no.1
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• pp.90-100
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• 2004

Objective : Urinary tract infection(UTI) is a frequent serious bacterial infection in young infants. The clinical presentation may be non-specific and variable, depends on factors such as the age and the level of infection. Children with renal involvement may be at risk of permanent renal damage. Experimental studies have shown that renal lesions caused by acute febrile UTI may be prevented or diminished by early diagnosis and treatment. Therefore, it is important to find a method that can permit early diagnosis and identification of patients who are at risk for progressive renal damage. We designed this study to identify related factors in culture positive UTI infants, and also to identify related factors in culture negative UTI infants, who are febrile with pyuria, by using renal imaging and functional studies including renal sonography, DMSA scan and VCUG. Methods : Retrospectively analyzed the medical records of 136 febrile infants with pyuria over 2 years(from January 2001 to February 2003). Urine culture was done in all cases, and regardless of urine culture findings, renal imaging study was done if symptomatic UTI suspected. Results : Total 57 organisms were isolated in 53 patients. E. coli was the most common organism(86%), followed by E. faecalis, M. morganii, Proteus species, P. aeruginosa, S. aureus and E. fergusonii. Most of the isolates had high sensitivity on cephalosporins or amikacin and had low sensitivities on aminopenicillins. Abnormal acute phase DMSA scan or VCUG findings were seen in both urine culture positive and negative group without statistical differences(P>0.05). In febrile infants with pyuria, fever over 48 hours, older age and high CRP related to abnormal acute phase DMSA scan findings regardless urine culture results. Conclusion : 1st or 3rd generation cephalosporins with amikacin could be the first choice of treatment for UTI. Febrile infants with positive urine culture dose mean urinary tract infection but not acute pyelonephritis which directly relates to cortical damage which could be confirmed by acute phase DMSA scan. Even cases with negative urine culture findings, acute pyelonephritis should be concerned in febrile infants with pyuria who are older than 3 months of age, has fever over 48 hours or high CRP level. And in such cases, acute phase DMSA scan and VCUG should be evaluated for early treatment and long term prognosis.

• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.1
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• pp.35-40
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• 2011

Purpose: This study was performed to evaluate the diagnostic usefulness of ankle stress radiograph for evaluation of chronic lateral ankle instability. Materials and Methods: Among patients undergoing the modified-Brostrom procedure, 42 cases with complete rupture of the anterior talofibular ligament were enrolled in this study. Sixty Korean adults (120 cases) were recruited as the control group. Radiologic measurement of talar tilt and anterior talar translation was performed through stress radiographs using Telos device. We obtained the normal range of Korean adults, and used as a standard value for judgment of mechanical instability. We analyzed the sensitivity, specificity, positive and negative prediction value of ankle stress radiograph. Results: On ankle stress radiograph, normal range of talar tilt angle and anterior talar translation was below $8.3^{\circ}$, below 7.6mm. Talar tilt angle on varus stress radiograph showed 57% of sensitivity, 97% of specificity, 89% of positive and 86% of negative prediction value. Anterior talar translation on anterior drawer stress radiograph showed 69% of sensitivity, 97% of specificity, 91% of positive and 90% of negative prediction value. Conclusion: Ankle stress radiograph had a good specificity, positive and negative prediction value for the evaluation of mechanical instability. However it underestimated the mechanical instability of ankle joint. It must be remembered that normal stress radiograph does not exclude ankle instability.

• Proceedings of the KSPS conference
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• 2005.04a
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• pp.77-80
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• 2005

The aim of this paper was to analyze the lexical effects on spoken word recognition of Korean monosyllabic word. The lexical factors chosen in this paper was frequency, density and lexical familiarity of words. Result of the analysis was as follows; frequency was the significant factor to predict spoken word recognition score of monosyllabic word. The other factors were not significant. This result suggest that word frequency should be considered in speech perception test.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.3
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• pp.132-142
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• 2023

Human leukocyte antigen (HLA) typing was performed in the diagnostic immunology laboratory of the Seoul National University Hospital. Among 611 HLA-DR tests, specific bead reactions suspected of being false positive and false negative in Lot 20 reagents were found. Therefore, we aimed to identify the factors causing cut-off corrections by examining cases where cut-off corrections were not made for 533 test results and cases where cut-off corrections were made for 78 cases after the cut-off corrections of specific beads. Frequency analysis was conducted to verify the demographic characteristics, and descriptive statistics were used to assess the humidity in the laboratory as a variable. Cross-tabulation was done to examine the association between cut-off corrections and demographic characteristics. Independent samples t-tests were conducted to verify the difference in humidity based on cut-off corrections. Finally, logistic regression analysis was conducted to examine the relationship between humidity levels and the rate of cut-off corrections, and results showed as the humidity level in the laboratory highs, the number of cut-off corrections decreased by a factor of 0.986. This suggests cut-off corrections rate increases when the humidity lowers. Therefore, it indicates that humidity in the laboratory is also a factor that affects HLA typing results.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.14 no.1
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• pp.16-25
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• 2003

Background and Objectives : Electroglottography(EGG) is a non-invasive method of monitoring the vocal cord vibration by measuring the variation of physiological impedance across the vocal folds through the neck skin. It reveals especially the vocal fold contact area and is widely used for basic laryngeal researches, voice analysis and synthesis. The purpose of this study is to investigate the effectiveness of EGG parameters in differential diagnosis of laryngeal cancer. Materials and Methods : The author investigated 10 laryngeal cancer and 25 benign laryngeal disease patients who visited at the Department of Otolaryngology, Pusan National University Hospital. The EGG equipment was devised in the author's Department. Among various parameters of EGG, closed quotient(CQ), speed quotient(SQ), speed index(SI), Jitter, Shimmer, Fo were determined by an analysis program made with MATLAB 6.5$^{\circledR}$(Mathwork, Inc.). In order to differentiate various laryngeal diseases from pathologic voice signals, the author has used the electroglottographic parameters using the neural network of multilayer perceptron structure. Results : SQ, SI, Jitter and Shimmer values except those of CQ and Fo showed remarkable differences between benign and malignant laryngeal disease groups. From the artificial neural network, the percentage of differentiating the laryngeal cancer was over 80% in SQ, SI, Jitter, Shimmer except for CQ and Fo. These results indicated that it is possible to discriminate the benign and malignant laryngeal diseases by EGG parameters using the artificial neural network. Conclusion : If parameters of EGG which can reveal for the pathology of laryngeal diseases are additionally developed and the current classification algorithm is improved, the discrimination of laryngeal cancer will become much more accurate.

• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.79-89
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• 1997

Purpose : Neonatal bacterial meningitis is the disease which clinical manifestations are nonspecific and several neurologic complications may occur. We studied neonatal bacterial meningitis, particularly in treatment and prognosis according to causative organisms -gram positive and gram negative bacteria- to assist in treatment of neonatal bacterial meningitis. Methods : We analysed twenty-four cases retrospectively who had been admitted in NICU or pediatric ward in Chung-ang Gil hospital from Jan. 1991 to Jun. 1996, and who had proven causative organisms in culture or latex agglutination[n test in CSF. Results : 1) The ratio of male to female was 2.4: 1. The mean birth weight and gestational age in cases with gram positive bacterial meningitis were $2.91{\pm}0.79kg$ and $38.4{\pm}2.74$ weeks and those in cases with yam negative bacterial meningitis were $3.30{\pm}0.90kg$ and $37.7{\pm}3.33$weeks respectively. There was no significant difference between the two groups. 2) The perinatal predisposing factors were pematurity, mecoinium staining amnionic fluid, matemal diabetes and pregnancy-induced hypertension, etc. The clinical manifestations Were fever, seizure, poor oral intake and fontanel bulging, etc. There were eleven cases with early onset bacterial meningitis(four cases by gram positive bacteria, seven cases by gram negative bacteria), and thirteen cases with late onset bacterial meningitis(seven cases by gram positive bacteria, six cases by gram negative bacteria). There was no significant difference between the two groups in terms of onset. 3) There were eleven cases with yam positive bacterial meningitis and they were coagulase-negative staphylococci(three cases), group B streptococci(three cases), Staphylococcus aureus(two cases), Streptococcus viridans(two cases), and enterococci(one case). And there were thirteen cases with gram negative bacterial menir gitis and they were Escherichia coli(seven cases), Klevsiella pneumoniae(three cases), Pseudomonas aeruginosa(one case), Acinetobactor(one case) and Enterobacter(one case). 4) The initial CSF WBC counts in cases with yam negative bacterial meningitis were significantly higher than those in cases with gram positive bacterial meningitis but the CSF protein and glucose levels were no significant difference in the two groups statistically. 5) The number of cases with abnormal findings in brain ultrasonography was seven in gram positive bacterial meningitis and ten in gram negative bacterial meningitis. 6) There were relatively high sensitivity to penicillin derivatives, the first generation cephalosporin and vancomycin in gram positive bacteria and to the third generation cephalosporin and amikacin in gram negative bacteria. 7) The mortality rate was 20.8%(5 cases were expired or discharged hopelessly). There was no significant difference between the two groups in prognosis. Conclusions : We recommend active treatment in noenatal bacterial meningitis to improve prognosis because the prognosis is poor.