DESIGN OF FILTER LENGTH OF ORDER FILTER AND ITS APPLICATION TO FILTERED-X ALGORITHM FOR ACTIVE NOISE CANCELLATION OF INTERIOR NOISE INSIDE AN EXCAVATOR CABIN

백지선,이창훈,유지환,이상권,최기수,김성재,김형호 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.5

This paper presents a novel method to determine the filter length. Major interior noises inside an excavator cabin are hydraulic pump noise. The filtered x-LMS (FxLMS) algorithm using a notch filter has been widely applied to ANC of engine noise inside the cabin of a passenger car. A notch adaptive filter is a comb-type filter and is useful to attenuate a steady-state pure tone. When the rotating speed of the crankshaft accelerates steadily in sweep mode, instantaneous frequencies of the hydraulic pump noise and cooling fan noise inside an excavator cabin increase steadily. The FxLMS algorithm using a notch filter can be stably applied to the ANC of the interior noise inside an excavator cabin in steady sweep mode. However, when a hydraulic pump is operated in dynamic mode, the rotating speed of the crankshaft fluctuates rapidly due to rapid change of the working load, and instantaneous frequencies of the hydraulic pump noise are also periodic and fluctuate rapidly. The FxLMS algorithm using an order filter is effective for ANC of the noise in which the instantaneous frequency rapidly fluctuates. For effective application of the order filter to ANC of non-stationary noise, the filter length should be optimally determined.

코로나19 발생 이후 사업체의 매출 변화와 이의 지역 간 차이

백지선 한국응용경제학회 2022 응용경제 Vol.24 No.2

본 논문은 BC카드사의 신용카드 지역(동)별 매출 데이터를 이용하여, 코로나19 이후 사업체의 매출 변화는 각 지역별로 다르게 나타나며, 해당 변화의 지역 간 이질성은 업종별로 다를 수 있음을 밝혔다. 주거 기능이 밀집된 지역의 경우 코로나19 유행 이후 신용카드 가맹점의 피해가 상대적으로 적었으며, 업무 기능 혹은 상업 기능이 밀집된 지역은 그 피해의 규모가 컸다. 또한, 지역별 특성변수와 지역별 매출 변화의 상관관계는 업종별로 상이한 것으로 나타났다. 유통업, 일반음식, 음식료품 등의 업종에서는 매출변화와 지역별 특성변수가 통계적으로 유의미한 상관관계가 있었으나, 내구재 업종 등의 매출은 지역별 특성과 상관관계가 나타나지 않았다. 1차 확산기에 집단감염이 발생했던 레저업소나 방역 조치의 직접적 규제의 대상이었던 유흥주점의 매출은 지역별 특성과 상관관계를 보이지 않았다.

[學位論文紹介] 『聊齋志異』의 문학적 치유성 연구

백지선 한국중국소설학회 2020 中國小說硏究會報 Vol.- No.110

Cause and Management of Patients With Failed Endonasal Dacryocystorhinostomy

백지선,정성훈,이정혜,최혜선,김성주,장재우 대한이비인후과학회 2017 Clinical and Experimental Otorhinolaryngology Vol.10 No.1

Objectives. Endonasal dacryocystorhinostomy (DCR) is a well-established treatment method in patients with nasolacrimal duct obstruction. However, there are a few reports about the overall management of failed endonasal DCR. We investigated the causes and management strategies of failed endonasal DCR. Methods. This retrospective review included 61 patients (61 eyes) who had undergone revision surgery by the same surgeon after failed endonasal DCR between January 2008 and December 2012. The appropriate revision method was determined after analysis of the etiology of failure by the fluorescein dye disappearance test, nasal endoscopy, lacrimal irrigation, and probing. The criteria for success of the revision surgery were defined by the passage of fluid without resistance upon lacrimal irrigation and normalization of the tear meniscus height. Results. The mean duration between the primary endonasal DCR and revision surgery was 15.3 months. The average follow-up period after revision surgery was 12.2 months. The most common cause of endoscopic revision surgery was membranous obstruction. Endoscopic revision surgery was performed in 48 patients, while lacrimal silicone tube intubation under endoscopy was performed in 13 patients. The most common indication for lacrimal silicone tube intubation was functional epiphora. The overall success rate of the revision surgery was 89%. Conclusion. The most common cause of failed endonasal DCR was membranous obstruction. When patients with failed endonasal DCR presented at the clinic, it is important to identify the cause of the failure. Revision surgery could increase the final success rate of endonasal DCR.

전남북 지역 맥류 붉은곰팡이병균의 Propiconazole 약제에 대한 감수성 변화

백지선,나주영,이미정,임수빈,최정혜,장자영,이데레사,최효원,김점순 한국균학회 2022 韓國菌學會誌 Vol.50 No.4

Fusarium head blight is an important disease of small grains. It is mainly caused by members of the Fusarium graminearum species complex (FGSC). Barley and wheat growers spray fungicides, especially demethylation-inhibitor fungicides, to suppress the disease. The objective of this study was to examine the changes in the sensitivity of the FGSC population to the triazole fungicide, propiconazole. A total of 124 and 350 isolates of FGSC were obtained from barley and wheat in Jeolla Province during 2010-2016 and 2020-2021, respectively. The species identity and trichothecene chemotypes of the FGSC isolates were determined based on polymerase chain reaction assays targeting translation elongation factor 1-alpha and TRI12 genes, respectively. Sensitivity to propiconazole was determined based on the effective concentration that reduced 50% of the mycelial growth (EC50) using the agar dilution method. Of all isolates, F. asiaticum with the nivalenol chemotype was the most common (83.9% in 2010-2016 and 96.0% in 2020-2021), followed by F. asiaticum with the 3-acetyl deoxynivalenol chemotype (12.1% in 2010-2016 and 2.9% in 2020-2021). The EC50 values of the isolates collected in 2010-2016 and 2020-2021 ranged from 0.0180 to 11.0166 μg/mL and 1.3104 to 17.9587 μg/mL, respectively. The mean EC50 value of the isolates increased from 3.8648 μg/mL in 2010-2016 to 5.9635 μg/mL in 2020-2021. The baseline resistance to propiconazole was determined to be 7 μg/mL, based on the EC50 value of isolates collected in 2010-2016, and the ratio of resistant isolates increased from 9.7% in 2010-2016 to 28.6% in 2020-2021.

Predictive Value of Dental Maturity for a Positive Gonadotropin-Releasing Hormone Stimulation Test Result in Girls with Precocious Puberty

백지선,최진우,김수진,김지현,김솔잎,김재현 대한의학회 2017 Journal of Korean medical science Vol.32 No.2

Dental maturity is associated with skeletal maturity, which is advanced in girls with central precocious puberty (CPP). We investigated the performance of dental maturity as a screening method for CPP using mandibular second premolar and molar calcification stages, assessed the associated anthropometric and laboratory factors, and evaluated pubertal response predictors using the gonadotropin-releasing hormone stimulation test (GnRHST) in prepubertal and pubertal girls. A prospective case-control study was conducted in girls, aged 7.0–8.9 years, classified into pubertal (peak luteinizing hormone [LH] after GnRHST ≥ 5 IU/L), prepubertal (peak LH < 5 IU/L), and control groups. Auxological and biochemical tests, panoramic radiographs, and GnRHSTs in participants with breast development were conducted. Dental maturity was assessed using the Demirjian index (DI). We included 103 girls (pubertal, 40; prepubertal, 19; control, 44). Chronological age (CA) was not significantly different between groups. Bone age (BA) and BA advancement was higher in the pubertal and prepubertal groups. Increased DI values at the mandibular second premolar and molar were significantly associated with CA, BA, BA advancement, height standard deviation score (SDS), peak LH after GnRHST, and insulin-like growth factor-I (IGF-I) (all P < 0.05). Moreover, odds ratio (OR) of the mandibular second premolar and molar (a DI value of ≥ E) for predicting a positive response to GnRHST was 8.7 (95% confidence intervals [CI], 2.9–26.1) and 5.2 (95% CI, 2.2–12.7), respectively. Dental maturity was a strong predictor for diagnosing CPP. Determining dental maturity in girls with suspected precocious puberty might help determine the performance of GnRHSTs.

능동 소음 제어를 이용한 자동차 실내 타이어 공명음의 저감

백지선,유진환,이상권,윤영삼,이재훈,염기호,황성욱 한국자동차공학회 2022 한국 자동차공학회논문집 Vol.30 No.10

This study proposesa new method for active noise cancellation(ANC) of cavity noise of a tire. A general method for ANC of road noise is to use several accelerometers for acquirement of reference signals. Cavity noise of tire is caused by the resonance of tire cavity mode. Resonance frequencies of tire cavity are determined by the cavity structure of tire. Therefore, harmonic sinusoidal signals can be used for reference signals. However,resonance frequencies could be varied due to small change of tire cavity during driving of a car. For the overcome of this variation, adaptive filter of ANC system was designed and applied to the ANC of a cavity noise. The proposed method didnot need accelerometers for the ANC of cavity noise and practically was applied to the ANC of cavity noise of a tire in a car. Cavity noise of a test was attenuated to 3-5dBA and effect of reduction was similar to passive method like resonant type tire.

병행적 혼합조사의 모드효과 분석

백지선,민경아,Baek, Jeeseon,Min, Kyung A 한국통계학회 2016 응용통계연구 Vol.29 No.5

사회환경 변화와 정보기술 발전에 따라 한 조사에 다양한 조사모드(survey mode)를 활용하는 혼합조사(mixed-mode survey)가 확대되고 있으며, 포함오차 축소, 비용절감, 응답률 향상 등의 장점을 가진다. 그러나 혼합조사는 선택효과와 측정효과가 혼재된 모드효과 발생으로 조사품질에 대한 우려가 있다. 통계개발원은 이러한 혼합조사의 모드효과를 파악하기 위하여 2014년에 병행적 혼합모드 시험조사를 수행하였다. 본 연구는 시험조사 자료에 대해 자기기입식 종이조사와 웹조사 간 모드효과를 선택효과와 측정효과로 분리하여 계량적으로 분석하였다. 선택계층의 효과를 분리하였을 때, 조사항목에 따라 과대 또는 과소 응답하는 측정효과가 존재하는 것을 확인하였다. Mixed-mode (MM) designs in which data are collected by different modes in one design have become increasingly popular. An MM data collection has several advantages such as reductions of coverage error, non-response and cost. However, MM designs may introduce mode effects that are confounded by selection effects and measurement effects, which can make MM data quality poor. In order to investigate mode effects, SRI implemented a concurrent mixed-mode experiment in 2014 where respondents could choose between a self-administrated Web survey and a self-administrated paper survey. This paper separately estimates selection effects and measurement effects. We found that measurement effects on some items are large.

Effect of the Introduction of High-speed Trains on Consumer Welfare

백지선 한국개발연구원 2016 KDI Journal of Economic Policy (KDI JEP) Vol.38 No.1

This paper examines the impact of introducing high-speed trains on consumer welfare, taking the ensuing changes in train schedules into account. Based on the estimated demand model for travel which incorporates consumer’s heterogeneous preferences for travel schedules into the standard discrete-choice model, I separately evaluate the impact from adding high-speed trains and that from changes in train schedules. The results indicate that consumers who travel between two cities connected by high-speed trains benefit from the introduction of high-speed trains, while some travelers whose choice set does not include high-speed trains face a reduced frequency of non-high-speed trains, resulting in significant losses.

Frontoethmoidal Mucocele Presenting as Progressive Enophthalmos

백지선,김수환,양석우 대한안과학회 2012 Korean Journal of Ophthalmology Vol.26 No.3

In this case report we describe a 27-year-old man who presented with progressive enophthalmos for 5 months without any other associated ocular symptoms such as pain, diplopia, or visual disturbance. Computed tomography showed that his progressive enophthalmos originated from a frontoethmoidal mucocele and this caused destruction of the lamina papyracea and shrinkage of the ethmoidal air cell. Finally the enlarged orbital space caused an inward deviation of the eyeball. Endoscopic marsupialization was successfully performed by an otolaryngologist and did not result in any ophthalmologic sequelae. Although frontoethmoidal sinus mucoceles mostly frequently originates from orbital mucoceles, enophthalmic manifestations are very rare. Enophthalmic conditions are not as responsive to surgical interventions as exophthalmic conditions.