• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 춘계학술대회논문집
• /
• pp.356-360
• /
• 2007

Fuel sloshing in a vehicle fuel tank generates a reluctant low frequency noise, called slosh noise. To reduce slosh noise, whilst many approaches have used the Computational Fluid Dynamics method to first identify fuel behavior in a fuel tank, this paper applies the Transfer Path Analysis method. It is to find contribution of each transfer path from noise transfer function, vibration transfer function and acceleration. Then the final goal is to attenuate slosh noise by controlling them. To this aim, two types of models are studied. One is the decoupled model in which some of connection points of the fuel tank with the vehicle underbody are separated. The other is the modified model which is created by changing noise transfer function and acceleration from the original model. The analysis and validation test results show that the transfer path analysis can be an approach to enhancing slosh noise.

• 한국소음진동공학회논문집
• /
• 제17권8호
• /
• pp.766-770
• /
• 2007

Fuel sloshing in a vehicle fuel tank generates a reluctant low frequency noise, called slosh noise. To reduce slosh noise, whilst many approaches have used the Computational Fluid Dynamics method to first identify fuel behavior in a fuel tank, this paper applies the Transfer Path Analysis method. It is to find contribution of each transfer path from noise transfer function, vibration transfer function and acceleration. Then the final goal is to attenuate slosh noise by controlling them. To this aim, two types of models are studied. One is the decoupled model in which some of connection points of the fuel tank with the vehicle underbody are separated. The other is the modified model which is created by changing noise transfer function and acceleration from the original model. The analysis and validation test results show that the transfer path analysis can be an approach to enhancing slosh noise.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제3권3호
• /
• pp.139-144
• /
• 2003

We report the results of extensive mixed mode simulations and theoretical analysis to quantify the contribution of the edge direct tunneling (EDT) current on the total gate leakage current of 80nm NMOSFET with SiO2 gate dielectric. It is shown that EDT has a profound impact on basic analog circuit building blocks such as sample-hold (S/H) circuit and the current mirror circuit. A transistor design methodology with zero gate-source/drain overlap is proposed to mitigate the EDT effect. This results in lower voltage droop in S/H application and better current matching in current mirror application. It is demonstrated that decreasing the overlap length also improves the basic analog circuit performance metrics of the transistor. The transistor with zero gate-source/drain overlap, results in better transconductance, input resistance, output resistance, intrinsic gain and unity gain transition frequency.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2005년도 춘계 학술발표회 논문집
• /
• pp.302-307
• /
• 2005

Love wave and Rayleigh wave are the major elastic waves belonging to the category of the surface wave. The fact that Love wave is not contaminated by P-wave which makes Love wave superior to Rayleigh wave and other body waves. Therefore, the information that Love wave carries is more distinct and clearer than the information of Rayleigh wave. Based on theoretical research, the joint inversion analysis which is used both Love wave dispersion information and Rayleigh wave dispersion information was proposed. Purpose of the joint inversion analysis is to improve accuracy and convergency of inversion results utilizing that frequency contribution of each wave is different. This analysis technique is consisted of the forward modeling using transfer matrix, the sensitivity matrix determined to the ground system and DLSS(Damped Least Square Solution) as a inversion technique. The application of this analysis was examined through the field test.

• The Journal of Asian Finance, Economics and Business
• /
• 제8권2호
• /
• pp.99-109
• /
• 2021

This study aims to examine the causal links between the fiscal components, i.e., government expenditures (GE) and government revenues (GR), and their impact on the economic growth of the Association of Southeast Asian Nations (ASEAN) region. This analysis considered secondary panel data from 1990 to 2019 at an annual frequency. The data is obtained from the Asian Development Bank (ADB) and World Bank Database. A panel cointegration and panel DH causality (Dumitrescu and Hurlin) approach was employed on financial data at an annual frequency from 1990 to 2019. The findings from panel unit root and panel cointegration tests demonstrate that, at first, all the variables are stationary and cointegrated. The panel ARDL disclosed that GE has a long-run connection with GDP, is significantly and positively associated with economic growth in the long run, whereas GR is significant in the short run. The contribution of GE is high in sustaining economic growth as compared to GR. Also, cointegration regression disclosed that GE is more sensitive toward GDP, while GR is less elastic. Lastly, the findings reveal that bidirectional causality exists between GE and GR variables. These results have policy implications for sustainable economic growth in the ASEAN region.

• 한국소음진동공학회논문집
• /
• 제26권7호
• /
• pp.774-780
• /
• 2016

In this paper noise source and transfer path of tactical vehicle are analyzed with partial coherence function and spectrum analysis. Engine, transmission, structure panel and aerodynamic are main source of cabin noise. To reduce cabin noise, identifying transfer path of sources and analyzing their contribution is important. With modeling of transfer path and partial coherence function, transfer path and principal noise source can be identified. Engine/transmission and structural resonance are principal source of low frequency noise and by adding stiffener and sound absorbing material, resonance of vibration and inflow air problem can be solved.

• 한국철도학회논문집
• /
• 제15권2호
• /
• pp.147-153
• /
• 2012

철도교량과 같이 주기적 가진에 의해 공진발생의 가능성이 높은 구조물에 있어서, 정확한 구조물의 동적거동 분석은 설계단계 및 공용중 안정적인 응답을 확보하기 위해 필수적이다. 특히, 콘크리트궤도는 강성기여와 질량기여를 통해 철도교량의 동특성을 변화시킬 수 있음에도 불구하고 일반적으로 철도교량 동적해석 시 질량으로만 고려되어진다. 본 연구에서는 실제 콘크리트궤도가 부설된 거더시험체를 제작하여 철도교량의 정 동적거동을 분석하였다. 또한, 궤도질량만을 고려한 경우와 궤도강성을 고려한 수치해석을 통해 중립축 위치와 고유진동수를 실험치와 비교 분석하였다. 이를 통해 콘크리트궤도 부설 철도교량의 경우 정량적인 산정이 가능한 콘크리트궤도의 강성과 질량을 고려한 해석값이 실험값과 근사한 결과를 얻을 수 있음을 확인하였다. 따라서 본 연구에서는 콘크리트궤도 부설 철도교량에 대한 동적설계 및 동적안정성 분석 시 콘크리트궤도의 강성과 질량을 함께 고려할 것을 제안하였다.

• 대한후두음성언어의학회지
• /
• 제17권2호
• /
• pp.115-126
• /
• 2006

Background and Objectives : Training of breath support and laryngeal muscles control are important components in the development of the singing voice. The purpose of this study is to compare characteristics of respiratory and phonatory control on pitch, loudness, register change with untrained males and trained male singers. Materials and Methods : The 11 untrained males and 11 trained male singers participated. Closed Quotient(CQ), fundamental frequency (fo) and relative volume contribution of the rib cage (in percentage rib cage, % RC) and relative volume contribution of abdomen (in percentage abdomen, % AB) were measured during various pitch, loudness, register tasks using /a/ vowel phonation : Legato, staccato with C3-D3-E3-F3-G3 notes and crescendo and decrescendo with C3 note as well as modal register with C3 and falsetto register with C4 note using an integrated analysis system of Respiration, EGG and Voice. Results : (1) When pitch increased with legato task, loudness also increased in untrained male group but maintained in trained male singers. CQ was also increased both untrained and trained male singers but it was not significantly different ($p>.05$). The abdomen contribution to lung volume were significantly predominant both in inhalation and exhalation in trained males singers ($p<.05$). (2) When pitch increased with staccato task, CQ was not significantly different in untrained but significantly different in trained male singers. The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$) (3) When loudness increased with crescendo, fo was significantly increased with increasing CQ in untrained males but fo was relatively consistent with increasing CQ in trained male singers. The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$). (4) Most male singers were able to change register from modal to falsetto register, but untrained males were not. Thus, CQ was significantly different between modal and falsetto register in trained male singers ($p<.05$). The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$). Conclusion : Male singers were superior to untrained males in coordination of respiratory and phonatory control on pitch, loudness, register change. Implication are offered regarding how the results might be applied to the voice therapy as well as singing training.

• 한국환경보건학회지
• /
• 제49권5호
• /
• pp.262-274
• /
• 2023

Background: Exposure levels for heavy metals such as lead (Pb), mercury (Hg), and cadmium (Cd) have increased due to human activities. They are known to be a public health concern. Objectives: This study aimed to determine the exposure levels to heavy metals in the blood and urine of South Korean adults and to present the contribution rate of exposure pathways using an exposure algorithm for men aged 19~64, women aged 19~64, and all seniors aged 65 or older. Methods: We analyzed data from the Korean National Environmental Health Survey (KoNEHS) Cycle 4 (2018~2020). A total of 2,646 participants aged ≥19 years were included. Multiple regression analysis was performed to determine the factors affecting heavy metal concentrations. The contribution rate was calculated by applying three exposure algorithms for ingestion, inhalation, and dermal exposure. Results: Factors that commonly affect heavy metal concentrations in blood and urine were gender and age. The main influencing factors for Pb and Cd were education level and smoking status, while frequency of fish consumption and of alcohol consumption were indicated to be the main influencing factors for mercury. The contribution rates of lead and cadmium from food ingestion were 78.03~79.62% and 88.39~92.89%, respectively. Additionally, the highest contribution for mercury was accounted for by food at 81.69~85.77%. As a result of the risk assessment, cadmium was found to pose a potential health risk a with total cancer risk (TCR) of more than 1×10^-6. Conclusions: The KoNEHS could be an important study for determining the level of exposure to heavy metals and their influencing factors. Integrated exposure to heavy metals could assess the main exposure pathways, and this methodology could be applied to exposure management of heavy metals.

• 소음진동
• /
• 제8권6호
• /
• pp.1158-1165
• /
• 1998

실내 저주파 소음은 도로가진, 차량 현가 또는 엔진 마운트와 같은 차량 샤시 부품의 진동인 구조 진동에 기인한다. 실내 저주파 소음을 줄이려는 노력의 일환으로 소음 원의 위치 및 소음 전달경로를 추적하는 기술인 TPA (Transfer Path Analysis) 를 소개하였다. 본 연구에서는 TPA 기술을 이론적으로 고찰해보고 이를 실제로 적용하여, 도로가진에 의해 앞 좌석에서의 실내 소음에 기여도가 가장 큰 샤시 부품을 찾는 Case Study를 소개하였다. TPA를 적용하기 위한 데이터를 얻기 위해. 도로가진에서 소음으로 연결되는 계측과 실차 운행 상태의 진동 데이터 계측을 실시하였다. 또한 아스팔트 도로에서 시속 30 km/h로 달리면서 관능 평가와 진동 소음 계측 평가 모두를 실시하여 문제가 되는 저주파 실내 소음을 확인하였다. 시험 분석 결과 Trailing Arm을 통해 전달되는 소음이 앞 좌석 저주파 실내 소음에 대한 기여도가 가장 크게 나타났다.