• Communications for Statistical Applications and Methods
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• 제17권6호
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• pp.909-916
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• 2010

A trend in software reliability engineering is to take into account the coverage growth behavior during testing. A coverage growth function that represents the coverage growth behavior is an essential factor in software reliability models. When multiple competitive coverage growth functions are available, there is a need for a criterion to select the best coverage growth functions. This paper proposes a selection criterion based on the prediction error. The conditional coverage growth function is introduced for predicting future coverage growth. Then the sum of the squares of the prediction error is defined and used for selecting the best coverage growth function.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.972-975
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• 2004

In order to reduce the noise of BLDC motor, a systematic optimization procedure for rotor structure is presented. The noise index is defined as the sum of volume velocity of FE-model that are calculated at the dominant frequencies during dehydration process, which is based on the principle of radiation simple volume source. Then, the five design variables are selected to represent the shape and layout or rotor structure. This discrete design optimization problem for minimizing the noise index is solved by 3-level orthogonal array based effect analysis. Finally, the response surface method (RSM) combined optimization approach is employed for more refining the approximate optimum.

• 한국신뢰성학회지:신뢰성응용연구
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• 제7권3호
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• pp.127-136
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• 2007

The accelerated life tests(ALTs) and degradation characteristics of image intensifier assembly(KIT-7) under low illuminance and high temperature were investigated. The accelerated life tests were carried out at $5{\times}10^5\;fc-40^{\circ}C,\;10{\times}10^5\;fc-40^{\circ}C,\;5{\times}10^5\;fc-50^{\circ}C,\;10{\times}10^5\;fc-50^{\circ}C$ and relationship related to illuminance and temperature was used as an accelerated life test model. An ALTA program[6] was used to calculate an acceleration factor and the test of life distribution fit, and estimate three parameters of an life test model. To sum up, MTTF 10,000 h at $5{\times}10^{-5}\;fc-40^{\circ}C$ of image intensifier assembly was certificated.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.2125-2129
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• 2008

In present, RCM has been hot issue in the domestic railway industry areas. Based on this circumstance, in this paper, for the purpose of an effective RCM system construction, a suitable organization structures which are to be applied to the railway system is proposed. Some examples and descriptions about the responsibilities and the roles which should be done by each RCM team, during the RCM analysis, as step by step for RCM analysis are also described. By using the formalized organization, the tasks for maintenance are allocated to each staff and the data for RCM analysis could be managed, systematically, as well. To sum up, it would be expected that based on the systematic organization structure for RCM analysis, the results of RCM analysis, that mean the maintenance methods and intervals for preventive maintenance, on specific railway system could be more reliable and accurate.

• Nonlinear Functional Analysis and Applications
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• 제26권4호
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• pp.855-868
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• 2021

If p(z) is a polynomial of degree n having all its zeros in |z| ≤ k, k ≤ 1, then for 𝜌R ≥ k² and 𝜌 ≤ R, Aziz and Zargar [4] proved that $${\max_{{\mid}z{\mid}=1}}{\mid}p^{\prime}(z){\mid}{\geq}n{\frac{(R+k)^{n-1}}{({\rho}+k)^n}}\{{\max_{{\mid}z{\mid}=1}}{\mid}p(z){\mid}+{\min_{{\mid}z{\mid}=k}}{\mid}p(z){\mid}\}$$. We prove a generalized L^r extension of the above result for a more general class of polynomials $p(z)=a_nz^n+\sum\limits_{{\nu}={\mu}}^{n}a_n-_{\nu}z^{n-\nu}$, $1{\leq}{\mu}{\leq}n$. We also obtain another L^r analogue of a result for the above general class of polynomials proved by Chanam and Dewan [6].

• Communications for Statistical Applications and Methods
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• 제29권4호
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• pp.453-469
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• 2022

The study of immune cellular composition has been of great scientific interest in immunology because of the generation of multiple large-scale data. From the statistical point of view, such immune cellular data should be treated as compositional. In compositional data, each element is positive, and all the elements sum to a constant, which can be set to one in general. Standard statistical methods are not directly applicable for the analysis of compositional data because they do not appropriately handle correlations between the compositional elements. In this paper, we review statistical methods for compositional data analysis and illustrate them in the context of immunology. Specifically, we focus on regression analyses using log-ratio transformations and the alternative approach using Dirichlet regression analysis, discuss their theoretical foundations, and illustrate their applications with immune cellular fraction data generated from colorectal cancer patients.

• 한국축산식품학회지
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• 제33권5호
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• pp.581-586
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• 2013

The objective of this study was to investigate the effects of supercritical carbon dioxide (SC-$CO_2$) treatment on meat quality and sensory evaluation of marinated pork. Meat marinated in two traditional Korean marinades, soy sauce and hot-pepper paste, and raw marinated meat were then treated with 7.4, 12.2, or 15.2 MPa $CO_2$ at $31.1^{\circ}C$for 10 min. The SC-$CO_2$ treatments had no effect on the meat pH (p>0.05) or Warner-Bratzler shear force (p>0.05). There was no significant difference (p>0.05) in the total loss (sum of treatment loss and cooking loss) between the control and SC-$CO_2$ treated samples at 15.2 MPa (soy sauce marinated pork: 21.78 vs. 18.97%; hot-pepper marinated pork: 21.61 vs. 18.01%). After the SC-$CO_2$ treatment, lighter surface colors were observed in the treatment samples compared to those of the control samples (p< 0.001). However, tasting panelists were unable to distinguish a difference in color or in overall acceptability of the control and treatment (p>0.05). In the case of soy sauce marinated pork, when SC-$CO_2$ applied at 15.2 MPa and $31.1^{\circ}C$for 10 min, treatment samples showed a tenderer meat than the control samples. Therefore, the SC-$CO_2$ treatment conditions had no adverse effects on the sensory quality characteristics of the marinated meat products.

• 한국항행학회논문지
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• 제12권5호
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• pp.437-443
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• 2008

본 논문에서는 다중사용자 환경의 상향링크 가상적 MIMO-OFDM 시스템 기반 하에서 정보 이론적인 관점에서의 합 전송률을 최대화 할 수 있는 최적의 사용자 수에 대하여 분석하였다. 다중 안테나 기반의 기지국과 단일 안테나용 단말기를 기반으로 하고 있으며 주파수 비선택적 블록 페이딩 및 시변 페이딩 채널 하의 파일럿 기반의 채널 추정 방식을 가정하였다. 이론적 분석을 통하여 낮은 SNR 영역에서 다중화 이득과 파일럿 오버헤드 간의 트레이드오프가 있음을 증명하였고 동일한 파일럿 및 신호 전력이 주어질 때, 주파수 비선택적 블록 채널에서의 시스템 성능을 최대화 하는 최적의 사용자 수는 min ($N_r$,LT/2)으로 결정되는 반면, 페이딩 채널에서는 min($N_r$, ${\lfloor}{\sqrt{LT+1}}-1{\rfloor}$)으로 접근함을 보여 준다.

• 한국대기환경학회지
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• 제30권2호
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• pp.95-109
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• 2014

In this study, the concentration of odorants released from albumin (EA) and yolk (EY) portions of boiled egg samples were determined as a function of storage time. The concentrations were measured at storage days of 0, 1, 3, 6, and 9 under room temperature. As such, odorants produced during both fresh and decay conditions were measured through time. A total of 19 compounds were selected as the main target odorants along with 12 reference compounds. GC-MS (for VOC) and GC-PFPD system (for sulfur gases) equipped with thermal desorption (TD) system were employed for odorant analysis in this work. The initial concentrations measured from the chamber system were converted into flux terms ($ng{\cdot}g^{-1}{\cdot}min^{-1}$). The EA showed the highest concentration of $H_2S$ (234 $ng{\cdot}g^{-1}{\cdot}min^{-1}$) at EA-0, and the concentrations of AT (Acetone) was also seen clearly in the range of 11.7 (EA-0) to 58.6 $ng{\cdot}g^{-1}{\cdot}min^{-1}$ (EA-9). The EY showed similar patterns. EtAl (Ethyl alcohol) increased 9.47 (EA-1) to 96.7 $ng{\cdot}g^{-1}{\cdot}min^{-1}$ (EA-9) in EA samples. Ketone, alcohol, sulfur groups generally exhibited high concentrations compared to other odorants. These data were also compared in relation to olfactometry related dilution-to-threshold (D/T) ratio by air dilution sensory (ADS) test and sum of odor intensity (SOI).

• 한국식품과학회지
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• 제30권1호
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• pp.103-109
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• 1998

생멸치를 열풍건조 후 마이크로파(MW), 마이크로파/열풍(MWH), 마이크로파 진공(MWV)의 건조방법들을 이용하여 5분 건조 1분 정지를 12회 및 10분 건조 1분 정지를 6회 반복하는 방법으로 처리하여 품질특성을 검토한 결과 수분함량, pH, 색도, 산도, 휘발성, 염기질소는 마이크로파 건조방법에 따라 큰 차이가 없는 것으로 나타났다. 지방산 조성은 대조구의 경우 포화산이 38.34%, 모노엔산이 22.91%, 폴리엔산이 38.75%로 나타났으며 마이크로파 건조방법도 각각 비슷한 구성을 나타내었고 각 건조방법 공히 palmitic acid와 docosahexaenoic acid의 함량이 많았다. 마이크로파 건조 후 마른 멸치의 palmitic acid의 함량이 대조구에 비하여 현저히 감소하는 것으로 나타났다. 주요 유리아미노산은 각 마이크로파 건조 방법 공히 alanine, arginine, lysine, leucine 등으로 나타났다. 조직감 측정은 대조구에 비교하여 마이크로파 건조 방법이 각 측정항목에 따라 큰 차이를 보이지 않았으며 관능검사 결과 마이크로파 진공 건조 방법이 가장 우수한 것으로 나타났다.