• 한국소음진동공학회논문집
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• 제18권7호
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• pp.746-755
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• 2008

This research presents a laboratory study on subjective response of impulsive sound caused by construction site (breaker and blasting). The sources are sampled from outdoor noise and their levels range from 40 to 75 dBA at the interval of 5 dBA. The noise unit is based on A-weighted sound exposure level(ASEL; $L_{AE}$). To make equal ASEL of listening level, finite impulse response(FIR) filter is applied to the originally sampled source to include the effect of propagation attenuation. Sixty-three subjects, forty-two males and twenty-one female, between 18 and 29 years of age, participated in the experiment. The evaluation method of jury test adopted a semantic difference method(SDM). In the test results for impulsive noise, the subjective response of blasting noise was higher than that of breaker noise. The result of %HA that has been combined responses of the three methods except for pink-noise was executed by regression analysis and was shown as the following equation.: $%HA=746.53/(1+{\exp} (L_{AE}-93.3))+0.34$.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1999년도 추계 학술대회논문집
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• pp.77-84
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• 1999

Numerical design optimization techniques are implemented for the improvement of the ram accelerator performance. The design object is to find the minimum ram tube length required to accelerate projectile from initial velocity $V_0$ to target velocity $V_e$. The premixture is composed of $H_2,\;O_2,\;N_2$ and the mole numbers of these species are selected as design variables. The objective function and the constraints are linearized during the optimization process and gradient-based Simplex method and SLP(Sequential Linear Programming) have been employed. With the assumption of two dimensional inviscid flow for internal flow field, the analyses of the nonequilibrium chemical reactions for 8 steps 7 species lave been performed. To determined the tube length, ram tube internal flow field is assumed to be in a quasi-steady state and the flow velocity is divided into several subregions with equal interval. Hence the thrust coefficients and accelerations for corresponding subregions are obtained and integrated for the whole velocity region. With the proposed design optimization techniques, the total ram tube length had been reduced $19\%$ within 7 design iterations. This optimization procedure can be directly applied to the multi-stage, multi-premixture ram accelerator design optimization problems.

• 대한수학회지
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• 제46권1호
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• pp.41-49
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• 2009

Let $\zeta$ be a fixed complex number. In this paper, we study the quantity $S(\zeta,\;n):=mas_{f{\in}{\Lambda}_n}\;|f(\zeta)|$, where ${\Lambda}_n$ is the set of all real polynomials of degree at most n-1 with coefficients in the interval [0, 1]. We first show how, in principle, for any given ${\zeta}\;{\in}\;{\mathbb{C}}$ and $n\;{\in}\;{\mathbb{N}}$, the quantity S($\zeta$, n) can be calculated. Then we compute the limit $lim_{n{\rightarrow}{\infty}}\;S(\zeta,\;n)/n$ for every ${\zeta}\;{\in}\;{\mathbb{C}}$ of modulus 1. It is equal to 1/$\pi$ if $\zeta$ is not a root of unity. If $\zeta\;=\;\exp(2{\pi}ik/d)$, where $d\;{\in}\;{\mathbb{N}}$ and k $\in$ [1, d-1] is an integer satisfying gcd(k, d) = 1, then the answer depends on the parity of d. More precisely, the limit is 1, 1/(d sin($\pi$/d)) and 1/(2d sin($\pi$/2d)) for d = 1, d even and d > 1 odd, respectively.

• 동력기계공학회지
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• 제9권4호
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• pp.18-23
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• 2005

The experimental investigation was carried out to evaluate the performance of air-to-air heat exchanger with rotating porous plates newly developed in this study. The rotating porous plates are mounted with an equal interval of 18 mm inside the heat exchanger where the hot and cold airs enter at opposite ends. When flowing in opposite directions by the separating plate installed in the center of the rotating porous plates, the airs give and receive the heat each other. The material of the porous plate is cooper and its thickness is 1.0 mm. Air flow rate is varied from 10 to 120 m3/h. From the experiment of air-to-air heat exchanger with the rotating porous plates, the heat exchange performance increased with the increase in RPM of the porous rotating discs at the conditions of the same air flow rate. The sensible heat exchange efficiency was maximum 60 to 70 percent, and enthalpy exchange efficiency 50 to 60 percent.

• 대한기계학회논문집B
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• 제31권3호
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• pp.306-312
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• 2007

This paper describes the flow characteristics of circular multiple jet investigated by hot-wire anemometry. The nozzle arrays were classified into two cases; 6- or 7-nozzle located circumferentially in equal interval without or with a central jet. The flow field was measured according to the number of nozzles when the Reynolds number based on the nozzle exit is about $10^4$. Mean velocity, Reynolds shear stress and turbulent kinetic energy were investigated in the downstream of jets. The Tollmien's theory holds for downstream only when a nozzle locates at the center. Jet interaction is influenced due to with or without a center nozzle. In addition, the two-dimensional numerical computation was conducted for 3-nozzle case to obtain the general flow structure near the nozzle exit, which verifies the formation of the recirculation region with captive vortices, that is, the evidence of the interaction between jets.

• Archives of Pharmacal Research
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• 제13권2호
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• pp.180-186
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• 1990

A bioequivalence study of ranitidine tablets was conducted according to the Korean Guidine for the Bioequivalence Test using twelve healthy male subjects. The plasma concentration-timecurves of ranitidine from the test and reference tablets showed profound multiple peak phenomenon in each subject as reported earlier. However, the area under the plasma concentration-time curve (AUC) and the maximum ploasma concentration at the first peak ($C_{max1}$) of the two preparations was proven to be equal when analyzed satistically according to the criteria of the guidline;i. e., statistical power (1-$\beta$)was calculated to be over 0.8 under the condition of $\alpha$ = 5% and $\Delta$(minimum detectable difference) = 20%, and the confidence interval of the difference in AUC at 95% confidence level was in the range of $\pm$ 20%, which statisfied the criteria of bioequivalence. Equivalence of the peak concentration of ranitidine at the second peak ($C_{max2}$), and the time to reach the first ($T_{max1}$) and second verify the bioequivalence of $c_{max2}$ , $T_{max1}$ and $T_{max2}$ between the two tablets. However, we conclude that the test and reference tablets are bioequivalent taking the therapeutic characteristics of the ranitidine preparations into consideration.

• 말소리와 음성과학
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• 제12권3호
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• pp.15-23
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• 2020

This study examines the duration of Korean lax and tense stops in the prosodic word-medial position, their interactions with nearby segments, and the phonological implications of these interactions. It first examines the lengthening of consonants at the function of the short lax stop. Experiment 1 shows that the sonorant C1 is significantly longer before a short lax stop C2 than before a long tense stop. Experiment 2 shows that the short lax stop C1 cancels the contrast between the lax and tense obstruent at C2, making them appear as long tense obstruents (Post-Stop Tensing Rule). We suggest that such lengthening phenomena occur in Korean to robustly preserve the contrastive length difference between C and CC. Second, this study examines the vowel shortening, known as Closed-Syllable Vowel Shortening, before a long tense stop or before the consonant sequence. Experiment 3 suggests that it be interpreted as temporal adjustment to make the interval from the onset of a vowel to the onset of the following vowel of near-equal length. Conclusively, we suggest that Korean speech be planned and controlled with two specific intervals. One is the duration of contrastive consonant intervals between vowels, and the other is the duration from the onset of a vowel to the onset of the following vowel.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6391-6395
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• 2012

Background: Ovarian cancer is ranked as the fifth most common cause of cancer death in women. In Malaysia, it is the fourth most common cancer in females. CA125 has been the tumor marker of choice in ovarian cancer but its diagnostic specificity in early stages is only 50%. Hence, there is a critical need to identify an alternative tumor marker that is capable of detecting detect ovarian cancer at an early stage. HE4 is a new tumor marker proposed for the early diagnosis of ovarian cancer and disease recurrence. Currently, none of the normal ranges of HE4 quoted in the literature are based on data for a multiethnic Asian population. Therefore, the aim of this study was to determine reference intervals for HE4 in an Asian population presenting in University Malaya Medical Centre, a tertiary reference hospital. Materials and Methods: 300 healthy women were recruited comprising 150 premenopausal and 150 postmenopausal women, aged from 20-76 years. All women were subjected to a pelvic ultrasonograph and were confirmed to be free from ovarian pathology on recruitment. Serum HE4 levels were determined by chemiluminescent microparticle immunoassay (CMIA, Abbott Architect). The reference intervals were determined following CLSI guidelines (C28-A2) using a non-parametric method. Results: The upper limits of the $95^{th}$ percentile reference interval (90%CI) for all the women collectively were 64.6 pmol/L, and 58.4 pmol/L for premenopausal) and 69.0 pmol/L for postmenopausal. The concentration of HE4 was noted to increase with age especially in women who were more than 50 years old. We also noted that our proposed reference limit was lower compared to the level given by manufacturer Abbott Architect HE4 kit insert (58.4 vs 70 pmol/L for premenopausal group and 69.0 vs 140 pmol/L in the postmenopausal group). The study also showed a significant difference in HE4 concentrations between ethnic groups (Malays and Indians). The levels of HE4 in Indians appeared higher than in Malays (p<0.05), while no significant differences were noted between the Malays and Chinese ethnic groups. Conclusions: More data are needed to establish a reference interval that will better represent the multiethnic Malaysian population. Probably a larger sampling size of equal representation of the Malay, Chinese, Indians as well as the other native ethnic communities will give us a greater confidence on whether genetics plays a role in reference interval determination.

• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5773-5775
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• 2012

Objective: To assess the diagnostic and prognostic value of AFP and des-gamma-carboxyprothrombin (DCP) in combination and alone for hepatocellular carcinoma. Materials and Methods: A case control study carried out in the Department of Biochemistry of Manipal College of Medical Sciences, Pokhara, Nepal between $1^{st}$ January 2010 and $31^{st}$ December 2011. The variables collected were age, gender, BMI, total proteins, albumin, AST, ALT, total bilirubin, DCP, AFP. Approval for the study was obtained from the institutional research ethical committee. Estimation of AFP was performed by ELISA reader for all cases. Analysis was done using descriptive statistics and confidence interval (CI). The data was analyzed using Excel 2003, R 2.8.0 Statistical Package for the Social Sciences (SPSS) for Windows Version 16.0 (SPSS Inc; Chicago, IL, USA) and the EPI Info 3.5.1 Windows Version. Results:The mean age of HCC cases was $53.6{\pm}14.93$ yrs. The percentage of females was less than males in both cases (23%) and controls (29%). The specificity of DCP reached 100% when its values was equal or greater than 150 (MAU/ml) for 0, 3, 6, 9, 12 months preceding the diagnosis of HCC. Similarly, the specificity for AFP was also nearly 100% when its value was equal or greater than 200 ng/ml 0, 3, 6, 9, 12 months earlier to the finding of HCC. The specificity of DCP (${\geq}40MAU/mL$) and AFP(${\geq}20$ ng/mL) in combination was 93%, 97%, 95%, 96%, 97% in respect to 0, 3, 6, 9, 12 months prior to the diagnosis of HCC. Conclusion: The combination of both DCP and AFP will improve the finding of initial HCC and the sensitivity of these markers was utmost at the time of HCC identification and noticeably lesser at former time points.

• 한국식물병리학회지
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• 제13권3호
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• pp.167-171
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• 1997

올방개 지문무늬병균(E. mematosporus)의 접종농도, 처리회수, 올방개의 모령이 제초효과에 미치는 영향을 온실에서 검정하였다. 포자현택액의 농도를 $10^{5}$ conidia/ml로 조정하여 분무접종하였을 때 15~20일 이내에 올방개 지상부 줄기의 82.6%~92.1% 정도가 고사하였으나, 그 이하의 농도에서는 제초효과가 53.7%이하로 급격히 감소하였다. 또한 지상부 줄기의 고사는 지하부 괴경형성에서도 영향을 미쳐, $10^{5}$ conidia/ml의 농도에서는 무처리나 $10^[3},\;10^{4}$ 농도의 처리에 비해 약 6~21배의 괴격형성 억제력을 나타내었다. 올방개 지문무늬평균 분생포자현탁액($6.3\;{\times}\;10^{5}$ conidia/ml)은 여러번 처리할수록 제초효과가 높았는데 2회 이상 처리했을 때 지상부 줄기의 고사율(93.8%)이 급격히 증가하였고 고사하기까지의 시간도 단축되었으며 신초의 발생율은 1회 처리에 비해 2.5배 무처리에 비해 12배 감소시켰고 지하부 괴경형성도 1회처리에 비해 6배, 무처리에 비해 35배 억제하였다. 올방개의 모령에 따라서도 제초효율에 차이가 있었는데 신초 형성후 20일 되었을 때 처리하는 것이 줄기 고사율이 가장 높았고, 신초의 발생율이 현저히 감소하였으며 또한 지하부 괴경형성 억제력도 높게 나타났다. 이상의 결과로 보아 올방개 지문무늬병균의 최적처리의 포자량은 $10^[5}$ conidia/ml 이상, 1주일 간격으로 2~3회 처리하며 신초형성 20일 후 처리하는 것이 가장 효과적이라 생각된다.