• 센서학회지
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• 제30권3호
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• pp.139-147
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• 2021

Numerical analysis was performed using FIMMWAVE to optimize the specifications of Si₃N₄/SiO₂ slot and ridge-slot optical waveguides based on confinement factor and effective mode area. The optimized specifications were confirmed based on sensitivity in terms of the refractive index of the analyte. The specifications of the slot optical waveguide, i.e., the width of the slot and the width and height of the rails, were optimized to 0.2 ㎛, 0.46 ㎛, and 0.5 ㎛ respectively. When the wavelength was 1.55 ㎛ and the refractive index of the slot was 1.3, the confinement factor and effective mode area of 0.2024 and 2.04 ㎛², respectively, were obtained based on the optimized specifications. The thickness of the ridge and the refractive index of the slot were set to 0.04 ㎛ and 1.1, respectively, to optimize the ridge-slot optical waveguide, and the confinement factor and effective mode area were calculated as 0.1393 and 2.90 ㎛², respectively. When the confinement coefficient and detection degree of the two structures were compared in the range of 1 to 1.3 of the analyte index, it was observed that the confinement coefficient and sensitivity were higher in the ridge-slot optical waveguide in the region with a refractive index less than 1.133, but the reverse situation occurred in the other region. Therefore, in the implementation of the integrated optical biochemical sensor, it is possible to propose a selection criterion for the two parameters depending on the value of the refractive index of the analyte.

• The Journal of the Acoustical Society of Korea
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• 제20권1E호
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• pp.31-37
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• 2001

Matched Field Processing (MFP) is a successive process of correcting mismatches between true and assumed parameters by matching the measured acoustic field data with numerically simulated data which we call replica. The MFP is widely used both in geo-acoustic parameter inversions and in source localizations. Whether a certain parameter can be inverted effectively or whether a source can be localized correctly depends on the amount of the influence that a parameter has on the acoustic field during the matching process. Sensitive parameters can be better estimated than the less sensitive ones in MFP. On the contrary, the sensitive parameters affect adversely on the source localization results when they have uncertainties. In this paper, a sensitivity index is defined based upon the field variation resulting from the perturbed parameters. Numerical test results show that the index behaves in accordance with the results of source localization under a mismatched environment and also with the inversion solutions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.244-249
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• 1998

The present paper improves the direct identification scheme based upon the equation error formulation with incomplete modal data. First, an indirect estimation technique is considered for estimating unmeasured elements of latent vectors by the combined use of a model and measured incomplete eigen vectors. It is used for estimating the other elements of eigen vectors, which are essential for identification but not available. Next an index is introduced here to indicate the quality of estimation with respect to the mode and the measured positions. A sensitivity formula for eigenvalues with respect to the unknown joint coefficient is also derived to select the modes appropriate for identification. An identification strategy is suggested to meet with practical problems with the help of the index and sensitivity formula. The index and the sensitivity are proved to be useful for selecting measurement positions and modes appropriate for identification A comprehensive simulation study is performed to test the proposed method.

• 한국조사연구학회지:조사연구
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• 제11권3호
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• pp.19-32
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• 2010

본 연구에서는 일반인들의 도박 중독 유병률 조사에 활용할 수 있는 단축형 조사도구를 개발하고, 도박 중독자 선별을 위한 기준점(cutoff score)을 탐색했다. 먼저 501명의 도박 이용자들을 대상으로 K-PGSI(Korean Problem Gambling Severity Index)의 단축형 척도를 개발했다. 문항을 선별하기 위해 원척도의 요인부하량과 문항-총점 간 상관, 응답자들의 반응 빈도나 전문가의 경험적 판단 등을 단계적으로 참고하여 요인타당도와 신뢰도가 양호한 네 문항의 단축형 척도를 개발했다. 다음으로 일반인 1,584명을 대상으로 단축형 척도를 교차타당화 하고, 도박 중독자 선별을 위한 기준점을 개발했다. 단축형 척도의 기준점으로 도박 중독 집단을 선별할 때 나타난 민감도(sensitivity)와 특이도(specificity)는 각각 1.00과 0.99로 모두 우수했다. 끝으로 도박 중독 유병률 조사에 본 척도를 어떻게 활용할 수 있을지 논의하였다.

• Current Optics and Photonics
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• 제3권3호
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• pp.199-203
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• 2019

The characteristics of a photonic crystal fiber sensor with reuleaux triangle are studied by using the finite element method. The wavelength sensitivity of the designed optical fiber sensor is related to the arc radius of the reuleaux triangle. Whether the core area is solid or liquid as well as the refractive index of the liquid core contributes to wavelength sensitivity. The simulation results show that larger arc radius leads to higher sensitivity. The sensitivity can be improved by introducing a liquid core, and higher wavelength sensitivity can be achieved with a lower refractive index liquid core. In addition, the specific channel plated with gold film is polished and then analyte is deposited on the film surface, in which case the position of the resonance peak is the same as that of the complete photonic crystal fiber with three analyte channels being filled with analyte. This means that filling process becomes convenient with equivalent performance of designed sensor. The maximum wavelength sensitivity of the sensor is 10200 nm/RIU and the resolution is $9.8{\times}10^{-6}RIU$.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.226-227
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• 2019

The basic type construction cost which is the base of the building cost estimation is being adjusted according to the price changes by utilizing the apartment construction cost index in order to flexibly operate it. In this study, we analyzed the change trends and characteristics of the housing cost index for the basic type building cost model project operated from September, 2012 to March, 2018. As a result, the increase in material costs is slight while the share of the labor cost increased in the construction cost due to the rise of labor unit price, leading to a perceived increase in sensitivity of labor costs. We should be careful to keep the sensitivity of the material cost and the labor cost to an appropriate level so that the index may not be distorted.

• 한국경영과학회지
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• 제25권4호
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• pp.1-14
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• 2000

The methods of sensitivity analysis for linear programming can be classified in two types: sensitivity analysis using an optimal solution, and sensitivity analysis using an approximate optimal solution. As the methods of sensitivity analysis using an optimal solution, there are three sensitivity analysis methods: sensitivity analysis using an optimal basis, positive sensitivity analysis, and optimal partition sensitivity analysis. Since they may provide different characteristic regions under degeneracy, it is not easy to understand and apply the results of the three methods. In this paper, we propose a generalized sensitivity analysis that can integrate the three existing methods of sensitivity analysis. When a right-hand side or a cost coefficient is perturbed, the generalized sensitivity analysis gives different characteristic regions according to the controlling index set that denotes the set of variables allowed to have positive values in optimal solutions to the perturbed problem. We show that the three existing sensitivity analysis methods are special cases of the generalized sensitivity analysis, and present some properties of the generalized sensitivity analysis.

• 한국물환경학회지
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• 제35권2호
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• pp.152-164
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• 2019

In this study, a Benthic Macroinvertebrates Family Index (BMFI) was developed using 100 indicator groups (99 families including Chironomidae with 2 phena). Families were assigned a score between 1 and 10 depending on their sensitivity to organic pollution. The BMFI was composed of the sensitivity and relative abundance of the indicator taxa. Sensitivity values of each group were generally similar to Biological Monitoring Working Party (BMWP) scores or Walley, Hawkes, Paisley, Trigg (WHPT) scores of UK, Japanese BMWP scores, and the FBI tolerance values of North America. However, sensitivity values of some taxa were significantly different from those of foreign countries, which seemed to have resulted from discrepancy in species composition, difference of taxonomic classification system, or methodological difference for estimation of sensitivity. As an annual average level, BMFI showed significant correlation with concentration of 5-day biochemical oxygen demand (BOD5) (correlation coefficient r = -0.80, n = 569 sites), total suspended solids (r = -0.68), and total phosphorus (r = -0.79). In addition, BMFI revealed strong correlation with Shannon-Weaver's species diversity (r = 0.85), Margalef's species richness (r = 0.85) and McNaughton's dominance (r = -0.84). Correlation between BMFI and water quality parameters or community indices such as species diversity did not show significant difference compared to that of species-level indices such as BMI (Benthic Macroinvertebrates Index). This means that BMFI is a more useful indicator in terms of easy identification of organisms. BMFI was used to assess the environmental status of 3,017 sites of Stream Ecosystem Survey conducted by the Korean Ministry of Environment between 2016 and 2018. As a result, about half of all sites appeared to be in good condition, and a quarter in poor condition.

• Advances in Traditional Medicine
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• 제7권2호
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• pp.205-210
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• 2007

The objectives of the study were (1) To evaluate the safety and tolerability of Damtab. (2) To characterize hypoglycemic effect of Damtab, if any. (3) To evaluate insulin sensitivity effect of Damtab, if any. Hypoglycemic effect of Damtab (700 mg and 1,400 mg) were examined. Gliclazide (80 mg) was used as an active control. Placebo was used as control. Breakfast was given, half an hour before dosing whereas lunch, snacks and dinner were given at 6, 10 and 14 h post dose. An oral glucose tolerance test was conducted to calculate the insulin sensitivity index from the values of glucose and insulin during oral glucose tolerance test. Both giclazide 80 mg and Damtab 1,400 mg significantly lowered plasma glucose level up to 6 h. Insulin sensitivity index of Damtab (1,400 mg) was found to be similar to that of placebo. A significant increase in insulin level at 1 h post dose of Damtab (1,400 mg) was observed. Damtab 700 mg shows placebo like effect whereas Damtab 1,400 mg possesses hypoglycemic effect.

• 한국대기환경학회지
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• 제22권4호
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• pp.421-430
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• 2006

This paper explores a new methodology of socio-statistical survey to classify environmental perception characteristics and to quantify atmospheric environmental sensitivity of neighboring people around a large industrial complex. In order to compensate intrinsic inclination against environmental problems, Atmospheric Environmental Sensitivity Index (AESI) is proposed as the weighted-summation of four representative questions asking the current status of the local air quality, which are chosen by the factor analysis of questionnaire. Atmospheric environmental perception is tried to be classified into interest/indifference characteristics and rational/emotional perception on environmental issues, positive/negative opinion on the solution of environmental problems. According to the chi-square cross-correlation and two-way layout analyses, it was clearly shown that environmental perception is categorized into two major groups, i.e., the positive-rational group having lower AESI and the negative-emotional group having higher AESI which means more seriously senses the status of local air quality.