• Archives of Plastic Surgery
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• v.33 no.2
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• pp.144-148
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• 2006

The velopharyngeal dysfunction usually occurs in patients with previous operation of the cleft palate or with submucosal cleft palate. In case of velopharyngeal dysfunction without cleft palate, no study has been made when it comes to operative method and postoperative results. Here, we would like to present the operative methods and the postoperative results with the cases we've experienced. This study is based on seven cases of velopharyngeal dysfunction without cleft palate from 1999 to 2004. Analysis of age, sex, etiology, operative methods, satisfaction rate and speech evaluation was done. The patients were 3 males and 4 females, with an age ranged from 10 to 28 at the time of surgery. The follow-up period was more than six months. One case had bifid uvula, another had atypical anomaly in palate, and five cases had no anatomical abnormality. The palatal lengthening was done on one patient, the levator muscle repositioning on another patient and to the rest of them, the superiorly based posterior pharyngeal flap was done. It was difficult to determine the etiology of the velopharyngeal dysfunction without cleft palate. The speech improvement and the satisfaction rate of the patients and parents were diverse. Although the authors had a problem with statistical analysis between the operative age and the speech improvement, it was reasonable to perform a surgical operation because postoperative speech improvement was observed in most cases regardless of age. There is little statistical correlation, but significantly higher outcomes were observed in palatal lengthening and levator muscle repositioning than in pharyngeal flap.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.2
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• pp.61-69
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• 2020

Purpose: Zirconia fixed partial dentures with mandibular 2^nd premolar and 2^nd molar as abutments are fabricated and then the effects of inter-abutment distance on fracture resistance of zirconia fixed partial dentures is studied. Materials and Methods: The materials used in this study are Cameleon S zirconia block and S2 zirconia block, which are divided into CS Group and S2 Group applying different inter-abutment distance for each material, and the sintered zirconia fixed partial denture was luted to the epoxy resin die using a temporary luting cement, and then the fracture resistance was measured by placing a 6 mm diameter hardened steel ball on the occlusal surfaces of the pontics and applying pressure at a cross head speed of 1.0 mm/min on a universal testing machine with a load cell of 5.0 kN. Results: The fracture resistance of zirconia fixed partial dentures is not significantly affected by inter-abutment distance The fracture resistance of zirconia fixed partial dentures in CS Group was significantly higher in 15 mm of inter-abutment distance than in 13 mm and 17 mm of inter-abutment distance (P < 0.05). The fracture resistance of zirconia fixed partial dentures in S2 Group was not significantly different between the three groups (P > 0.05). Conclusion: The fracture resistance of zirconia fixed partial dentures with mandibular 2^nd premolar and 2^nd molar as abutments does not significantly affected by the inter-abutment distance.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.385-388
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• 2008

Recycled fine aggregate has low quality because it contains large amount of old mortar. So, its usage is limited to a lower value-add, such as the roadbed material etc. Also, alkaline water occurred from treatment process of the waste concrete is becoming the cause of environmental problem. Accordingly, this study is to develop on the high quality recycled fine aggregate produced by low speed wet abraser using sulphuric. We investigated the properties of compressive strength of the mortar which was manufactured using recycled fine aggregate containing calcined gypsum produced by earlier mentioned process. Test results indicate that concrete using recycled fine aggregate containing calcined gypsum is higher compressive strength than concrete using other sands.

• Resources Recycling
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• v.2 no.2
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• pp.27-38
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• 1993

In this study, we investigated the grinding and sedimentation(elutriation) process of the dusts for the effective separation of high purity iron and iron oxides. For characterization of the dust, particle size distribution and chemical composition, were examined. The results obtained in this study may be summarized as follows : 1. The converter CF(clarifier) dust of the Pohang 1st, 2nd steel making factory and EC(Evaporation Cooler), EP(Eltrostatic precititator) dust of the Kwangyang 2nd steel making factory are composed $\alpha$-Fe(21~50%), FeO(wustite)$Fe_3$$O_4$(magnetite), $Fe_2$$O_3$, CaO, $Al_2$$O_3$, $SiO_2$, and etc. 2. Pure iron has ductile characteristic in nature, particle size of the pure iron increase by increasing the grinding time. On the other hand, it is conformed that bo고 particles of hematite and magnetite become less than 325 mesh after 10 minutes grinding. 3. By applying the elutriation technique for the EC dust of the Kwangyang 2nd steel making factory, the iron powder of high content more than 99.17% of pure Fe was recovered with 37.8% yield at grinding time for 40 minutes. 4. By applying the elutriation technique for the CF dust of the Pohang 2nd steel making factory, the iron powder of high content more than 98.38% of pure Fe was recovered with 44.42% yield at grinding time for 40 minutes. 5. When magnetic separation was performed using plastic bonding magnet of 70 gauss, more than 98% Fe grade of iron powder was recovered in the size range +65 -200 mesh but the recovery of it was low.

• Archives of Plastic Surgery
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• v.36 no.3
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• pp.294-298
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• 2009

Purpose: The pharyngeal flap is one of the popular surgical method to treat the problem of velopharyngeal dysfunction. This study evaluated speech outcomes of patients who underwent superiorly based pharyngeal flap surgery based on timing of surgery. Methods: A restrospective review of 50 patients who underwent pharyngeal flap surgery for velopharyngeal insufficiency between September 1996 and January 2008 was undertaken. Thirty patients with an available preoprative and postoperative speech assessments with at least 6 months of follow-up were included in this study. We checked out the significance of speech improvement after surgery analysing preoperative and postoperative scoring of speech assessment. We also investigated the direct relationship between the age at surgery and the degree of speech improvement, and the improvement score in different age groups. Results: The mean score of preoperative speech was $52.6{\pm}7.4points$ and postoperative speech was $58.6{\pm}6.5points$, which presented significant postoperative speech improvement with an average of 5.9 points(p<0.01). There was a significant inverse relationship between the age at operation and speech improvement degree(p<0.01, r = -0.54). Comparing the age groups, the age group of 4 to 5 years presented statistically significant speech improvement(p<0.01). Conclusion: we propose that all patients indicated should take pharyngeal flap irrespective of age. In this study, the younger the age at surgery, the higher degree of speech improvement, for which we suggest that surgical approach should be undertaken as early as possible, especially younger than age 5 years.

• Radiation Oncology Journal
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• v.8 no.2
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• pp.151-154
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• 1990

The acute effects of variable dos rates to total body irradiation (TBI) were investigaed with 600 cGy of single exposure in the mice as a preclinical model. Total 80 mice (ICR) were used. Twenty of which sewed as controls, receiving no irradiation. All irradiated mice showed a universal decline in their weight and white blood cell count. The degree of weight loss and leukopenia were similar at 3 different dos rate but slightly prominent with 15 cGy/minute group. The degree of recovery among the groups showed no dose rate dependence. Our results suggest that TBI with 15 cGy/mimute may be applicable for clinical therapy with careful evaluation of patient's condition.

• Journal of Korea Multimedia Society
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• v.11 no.11
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• pp.1471-1479
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• 2008

In this paper, we propose a technique to improve Out-Of-Vocabulary(OOV) rejection algorithms in variable vocabulary recognition system which is much used in ASR(Automatic Speech Recognition). The rejection system can be classified into two categories by their implementation method, keyword spotting method and utterance verification method. The utterance verification method uses the likelihood ratio of each phoneme Viterbi score relative to anti-phoneme score for deciding OOV. In this paper, we add speaker verification system before utterance verification and calculate an speaker verification probability. The obtained speaker verification probability is applied for determining the proposed variable-confidence threshold. Using the proposed method, we achieve the significant performance improvement; CA(Correctly Accepted for keyword) 94.23%, CR(Correctly Rejected for out-of-vocabulary) 95.11% in office environment, and CA 91.14%, CR 92.74% in noisy environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.718-721
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• 2011

In this paper, cross ambiguity function map is proposed to estimate the location of a unknown interferer which emits the harmful radio in the satellite communication network. To estimate the interferer, a time difference between received radio signals at earth stations and a frequency difference caused by the movement of interferers or receiving earth stations are calculated. Therefore, cross ambiguity function is used to calculate that values. The calculating process of the time and the frequency differences using cross ambiguity function is operated at every designated time then the correlation values between the time and frequency are calculated. After calcuation, the final location of the harmful interferer is estimated. From the simulation results, about 800 m distance error is occurred at 10~4 dB of $E_b/N_0$ and about 13 km distance errer is occurred at -20 dB of $E_b/N_0$.

• Archives of Plastic Surgery
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• v.33 no.3
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• pp.308-312
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• 2006

Time to time, we face patients who missed the proper time for primary palatal repair. Although we do not have enough available documents, it is important to establish efficacy of palatal repair in patients more than 4 years old. From May 1995 to March 2005, we selected 14 patients who underwent palatal repair in more than 4 years old patients and they are able to tolerate speech articulation tests. Out of 14 patients 5 males an 9 females in sex, aged form 4 to 50 years old. 6 patients with incomplete cleft palate and 8 patients with submucous cleft palate. Double reversing Z-plasty(n=5), pushback palatoplasty(n=4), two flap palatoplasty(n=2), von Langenbeck palatoplasty(n=2), and intravelar veloplasty(n=1) were performed. Preoperative and postoperative speech articulation test, "Simple method of speech evaluation in Korean patients with cleft palate", were conducted. Satisfaction rate was sorted into 5 levels. There is no significant statistical correlation in the speech improvement, satisfaction rate, patients sex, cleft type and operative method. But there is significant statistical correlation between the speech improvement and patienet's age. There were better result in younger patient group than aged patients group.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.265-274
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• 2019

The paper describes an application of unscented Kalman filter(UKF) for attitude estimation of an unmanned vehicle(UV), which is equipped with a low-cost attitude heading reference system (AHRS). The roll, pitch and yaw required at the correction stage of the UKF are calculated from the measurements of acceleration and geomagnetic field. The roll and pitch are attributed to the measurement of acceleration, while yaw is calculated from the geomagnetic field measurement. Since the measurement of geomagnetic field is vulnerable to distortion by hard-iron and soft-iron effects, the calculated yaw has more uncertainty than the calculated roll and pitch. To reduce the uncertainty of geomagnetic field measurement, the proposed method estimates bias in the geomagnetic field measurement and compensates for the bias for more accurate calculation of yaw. The proposed method is verified through navigation experiments of a UV in a test pool. The results show that the proposed method yields more accurate attitude estimation; thus, it results more accurate location estimation.