• Title/Summary/Keyword: Rate function

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The prediction of Performance in Two-Stroke Large Marine Diesel Engine Using Double-Wiebc Combustion Model (2중 Wiebe 연소모델을 이용한 2행정 대형 선박용 디젤엔진의 성능예측)

  • 김태훈
    • Journal of Advanced Marine Engineering and Technology
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    • v.23 no.5
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    • pp.637-653
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    • 1999
  • In this study well-known burned rate expressions of Weibe function and double Wiebe function have been adopted for the combustion analysis of large two stroke marine diesel engine. A cycle simulation program was also developed to predict the performance and pressure waves in pipes using validated burned rate function,. Levenberg-Marquardt iteration method was applied to cali-brate the shape coefficients included in double Wiebe function for the performance prediction of two-stroke marine diesel engine. As a result the performance prediction using double Wiebe func-tion is well correlated withexperimental dta with the accuracy of 5% and pressure waves in intake and transport pipe are well predicted. From the results of this study it can be confirmed that the shape coefficients of burned rate function should be modified using the numerical method suggested for the accurated prediction and double Wiebe function is more suitable than Wiebe func-tion for combustion analysis of large two stroke marine engine.

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A Study on the Aerodynamic and Acoustic Characteristics in Dysarthria Speakers' Diadochokinesis by Articulation Valves in Vocal Tract (마비성구어장애 화자의 조음밸브 교호운동에 관한 공기역학 및 음향학적 특징)

  • Park, Hee-June;Kwon, Soon-Bok;Wang, Soo-Geun;Jeong, Ok-Ran
    • Speech Sciences
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    • v.15 no.2
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    • pp.177-189
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    • 2008
  • This study was to investigate diadochokinetic (DDK) rate, regularity and mean flow rate of articulation valves in dysarthria. DDK rate, mean airflow rate (MFR) and regularity of DDK syllable repetitions of vocal function /ihi/, tongue function /ta/, velopharyngeal function /bm/, and labial function /pa/ in 24 normal and dysarthric speakers were measured. Aerophone Ⅱ and Motor Speech Profile were used for data recording and analysis. The results of the findings were as follows: First, there were significant differences between the dysarthria and the normal group in DDK rate. DDK rates in ataxic dysarthria were the lowest and spastic, flaccid, and hypokinetic dysarthria followed in sequence. Second, there was a significant difference between the dysarthria and the normal group in DDK regularity. Third, there was a significant difference between dysarthria groups and normal group in DDK MFR. Finally, there was a significant difference between the 4 groups of dysarthria and the normal group in DDK air flow tracking. The results of this study can be guidelines for normal DDK rate, regularity and flow rate in dysarthria groups. In addition, their differential diagnoses and descriptions are important to make a decision on medical and behavioral management of the individuals with disorders according to DDK characteristics.

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Effect of thoracic cage mobilization on respiratory function, spinal curve and spinal movement in patients with restrictive lung disease

  • Wang, Joong San
    • Journal of International Academy of Physical Therapy Research
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    • v.7 no.2
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    • pp.1006-1010
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    • 2016
  • This study aimed to examine the effects of thoracic cage mobilization on the respiratory function, spinal curve and spinal movement in patients with restrictive lung diseases. The subjects were ten community-dwelling elderly with a restrictive lung diseases when measured using a spirometer($FEV1/FVC{\leq}65%$, FVC<80%). They received an intervention over an eight-week period: three times a week and for 30 minutes a day. SPSS for Windows(ver. 19.0) was used to analyze all the collected data. Independent t-tests were used to examine changes before and after the intervention. The study's results showed statistically significant improvement(p<.05) in forced expiratory volume in 1 second(chage rate: .$24{\pm}.25$), thoracic curve(chage rate: $-2.50{\pm}2.76$), lumbar curve(chage rate: $-.80{\pm}1.32$), thoracic flexion(chage rate: $2.10{\pm}1.52$), thoracic extension(chage rate: $-2.00{\pm}1.25$), lumbar flexion(chage rate: $2.40{\pm}3.13$) and lumbar extension(chage rate: $-1.30{\pm}1.42$). The results of this study suggest that the thoracic cage mobilization contribute to improve pulmonary function in patients with restrictive lung disease.

A Study of Optimal Maintenance Schedules of a System under the Periodic Inspection Policy (주기적인 검사 정책하에서 최적예방 교체시기 결정에 관한 연구)

  • 정현태;김제승
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.20 no.44
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    • pp.263-271
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    • 1997
  • This paper presents a preventive maintenance model for determining the preventive replacement period of a system in which a failure rate is affected by the cumulative damage of fault and inspection. Especially, the failure rate function is considered to be a function of the cumulative damage of the fault and inspection time. Types of replacement considered are preventive replacement and failure replacement. Failure rate and expected cost function between replacement are derived. An optimal policy is obtained that minimizes the average cost per unit time for preventive replacement, failure replacement, inspection and repair.

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A Study of Two Rate Three Color Maker for Differentiated Service Network (차별화된 서비스 네트워크를 위한 two rate Three Color Maker에 관한 연구)

  • Nyamdagva, Nyamdagva;Ho, Kwang-Chun;Park, Chun-Kwan
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.9 no.5
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    • pp.23-30
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    • 2009
  • This paper addresses the design of trTCM (Two Rate Three Color Marker) described in RFC2698. It has proposed for trTCM to be used in Differentiated Service network that provides AF PHB (Assured Forwarding Per Hop Behavior). trTCM is the marker with the metering function, and consists of the token updating function and the marking function. The token updating function uses the dual token bucket. The marking function compares the token values with the length of input packet and then marks the result into IP QoS field (ToS field). In this paper, we design trTCM function and then addresses the scheme to implement it using FPGA technology.

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Design of Single Rate Three Color Marker using FPGA (EPGA를 이용한 Single Rate Three Color Marker 설계)

  • Park, Chung-Kwan
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.12
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    • pp.141-148
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    • 2005
  • This paper addresses the design of srTCM (single rate Three Color Marker) described in RFC2697. It has proposed for srTCM to be used at the ingress of Differentiated Service network that provides AF PHB (Assured Forwarding Per Hop Behavior). srTCM is the marker with the metering function, and consists of the token updating function and the marking function. The token updating function uses the dual token bucket. The marking function compares the token values with the length of input packet, and then marks the result into IP QoS field (ToS field). This paper designs srTCM function and then implements it in one chip using VHDL and FPGA technology.

Development of Replacement Models under Minimal Repair with Wavelet Failure Rate Functions (웨이브릿 고장률 함수를 갖는 최소수리 교체모형 개발)

  • 최성운
    • Journal of the Korea Safety Management & Science
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    • v.3 no.4
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    • pp.91-101
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    • 2001
  • This paper is to develop replacement models under minimal repair with exponential polynomial wavelet failure rate function. Wavelets have good time-frequency localization, fast algorithms and parsimonious representation. Also this study is presented along with numerical examples using sensitivity analysis for exponential polynomial trigonometric failure rate function.

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Consideration of Appropriate Thermal Storage Time of Air-Conditioning System with Slab Thermal Storage in an Office Building by Use of Measurement Value (실측치를 통한 사무소건물 슬래브축열 공조시스템의 적정 축열시간 검토)

  • Jung, Jae-Hoon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.10
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    • pp.719-726
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    • 2010
  • In this paper, the appropriate thermal storage time of an air-conditioning system with slab thermal storage was considered by use of summer measurement values. Two standards of heat extraction rate and criterion function were established as the standard that evaluates appropriateness. When heat extraction rate was a standard, zero hour and seven hours were obtained as appropriate thermal storage time, in the case of evaluation by energy consumption and running cost individually. Also, when criterion function was a standard, the difference between energy consumption and running cost was small, it was because the weight function to room air temperature deviation was much bigger than heat extraction rate.

Length-biased Rayleigh distribution: reliability analysis, estimation of the parameter, and applications

  • Kayid, M.;Alshingiti, Arwa M.;Aldossary, H.
    • International Journal of Reliability and Applications
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    • v.14 no.1
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    • pp.27-39
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    • 2013
  • In this article, a new model based on the Rayleigh distribution is introduced. This model is useful and practical in physics, reliability, and life testing. The statistical and reliability properties of this model are presented, including moments, the hazard rate, the reversed hazard rate, and mean residual life functions, among others. In addition, it is shown that the distributions of the new model are ordered regarding the strongest likelihood ratio ordering. Four estimating methods, namely, method of moment, maximum likelihood method, Bayes estimation, and uniformly minimum variance unbiased, are used to estimate the parameters of this model. Simulation is used to calculate the estimates and to study their properties. Finally, the appropriateness of this model for real data sets is shown by using the chi-square goodness of fit test and the Kolmogorov-Smirnov statistic.

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