• 호남수학학술지
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• 제40권3호
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• pp.377-389
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• 2018

The notion of a uni-soft commutative ideal with thresholds is introduced, and related properties are investigated. Relations between a uni-soft ideal with thresholds and a uni-soft commutative ideal with thresholds are discussed. Conditions for a uni-soft ideal with thresholds to be a uni-soft commutative ideal with the same thresholds are provided. Characterizations of a uni-soft commutative ideal with thresholds are established.

• Korean Journal of Radiology
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• 제21권6호
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• pp.756-763
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• 2020

Objective: To evaluate the effects of attenuation threshold on CT pulmonary vascular volume ratios in children and young adults with congenital heart disease, and to suggest an optimal attenuation threshold. Materials and Methods: CT percentages of right pulmonary vascular volume were compared and correlated with percentages calculated from nuclear medicine right lung perfusion in 52 patients with congenital heart disease. The selected patients had undergone electrocardiography-synchronized cardiothoracic CT and lung perfusion scintigraphy within a 1-year interval, but not interim surgical or transcatheter intervention. The percentages of CT right pulmonary vascular volumes were calculated with fixed (80-600 Hounsfield units [HU]) and adaptive thresholds (average pulmonary artery enhancement [PA_avg] divided by 2.50, 2.00, 1.75, 1.63, 1.50, and 1.25). The optimal threshold exhibited the smallest mean difference, the lowest p-value in statistically significant paired comparisons, and the highest Pearson correlation coefficient. Results: The PA_avg value was 529.5 ± 164.8 HU (range, 250.1-956.6 HU). Results showed that fixed thresholds in the range of 320-400 HU, and adaptive thresholds of PA_avg/1.75-1.50 were optimal for quantifying CT pulmonary vascular volume ratios. The optimal thresholds demonstrated a small mean difference of ≤ 5%, no significant difference (> 0.2 for fixed thresholds, and > 0.5 for adaptive thresholds), and a high correlation coefficient (0.93 for fixed thresholds, and 0.91 for adaptive thresholds). Conclusion: The optimal fixed and adaptive thresholds for quantifying CT pulmonary vascular volume ratios appeared equally useful. However, when considering a wide range of PAavg, application of optimal adaptive thresholds may be more suitable than fixed thresholds in actual clinical practice.

• 대한치과보철학회지
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• 제8권1호
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• pp.20-24
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• 1968

Recognition thresholds for representatives of the salt, sweet, bitter, and sour modalities of taste were determined in 25 patients with dentures. The following results were obtained. (1) Recognition thresholds for the taste of NaCl(salt) and Sucrose(sweet) were essentially unchanged with or without the dentures in place. (2) Recognition thresholds for HCl(sour) and Urea(bitter) increased after the patients inserted their dentures. The amount of increase was 59.4% and 112.5% for HCl and Urea, respectively. (3) Recognition thresholds for all four taste modalities inpatients with ill-fitting dentures were not significantly changed with or without dentures in place. (4) Recogniton thresholds for all four taste modalities in Korean were greater than those of Pfaffamann's.

• Nuclear Engineering and Technology
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• 제36권6호
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• pp.485-496
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• 2004

Typical probabilistic safety assessment (PSA) results were used to estimate the performance indicator (PI) thresholds of unplanned reactor scram (URS) and safety system unavailability (SSU) for Korean nuclear power plants (NPPs). The changes in core damage frequency (${\Delta}$CDFs) of $10^{-6}/yr$, $10^{-5}/yr$, and $10^{-4}/yr$ were adopted as the risk criteria in setting up the PI thresholds. The PI thresholds for the URS were estimated using information pertaining to the initiating event frequencies, the CDF, and the CDF contribution of each initiating event. The PI thresholds of the SSU were estimated using information on the unavailability, the Fussell-Vesely importance, and the CDF.

• Geomechanics and Engineering
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• 제12권4호
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• pp.639-655
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• 2017

The binary mixture consists of two types of granular media with different physical attributes and sizes, which can be characterized by the percentage of large granules by weight (P) and the particle size ratio (${\alpha}$). Researchers determine that two thresholds ($P_S$ and $P_L$) exist for the peak shear strength of binary mixtures, i.e., at $P{\leq}P_S$, the peak shear strength is controlled by the small granules; at $P{\leq}P_L$, the peak shear strength is controlled by the large granules; at $P_S{\leq}P{\leq}P_L$, the peak shear strength is governed by both the large and small granules. However, the thresholds of binary mixtures with different ${\alpha}$ values, and the explanation related to the inner details of binary mixtures to account for why these thresholds exist, require further confirmation. This paper considers the mechanical behavior of binary mixtures with DEM analysis. The thresholds of binary mixtures are found to be strongly related to their coordination numbers $Z_L$ for all values of ${\alpha}$, where $Z_L$ denotes the partial coordination number only between the large particles. The arrangement structure of the large particles is examined when P approaches the thresholds, and a similar arrangement structure of large particles is formed in both 2D and 3D particle systems.

• 지질공학
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• 제34권2호
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• pp.173-191
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• 2024

Landslides pose significant threats to many countries globally, yet the development and implementation of effective landslide early warning systems (LEWS) remain challenging due to multifaceted complexities spanning scientific, technological, and political domains. Addressing these challenges demands a holistic approach. Technologically, integrating thresholds, such as rainfall thresholds, with real-time data within accessible, open-source software stands as a promising solution for LEWS. This article introduces LandScient_EWS, a PHP-based program tailored to address this need. The software facilitates the comparison of real-time measured data, such as rainfall, with predefined landslide thresholds, enabling precise calculations and graphical representation of real-time landslide advisory levels across diverse spatial scales, including regional, basin, and hillslope levels. To illustrate its efficacy, the program was applied to a case study in Medellin, Colombia, where a rainfall event on August 26, 2008, triggered a shallow landslide. Through pre-defined rainfall intensity and duration thresholds, the software simulated advisory levels during the recorded rainfall event, utilizing data from a rain gauge positioned within a small watershed and a single grid cell (representing a hillslope) within that watershed. By identifying critical conditions that may lead to landslides in real-time scenarios, LandScient_EWS offers a new paradigm for assessing and responding to landslide hazards, thereby improving the efficiency and effectiveness of LEWS. The findings underscore the software's potential to streamline the integration of rainfall thresholds into both existing and future landslide early warning systems.

• Journal of Oral Medicine and Pain
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• 제32권4호
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• pp.413-419
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• 2007

다양한 종류의 정량적 통각검사들의 연관성을 알아보기 위하여 56 명의 측두하악장애 환자를 대상으로 측두근, 교근, 측두하악관절 부위, 그리고 경골근의 냉통각역치 (Cold Pain Threshold, CPT), 열통각역치 (Heat Pain Threshold, HPT), 열통증인내역치 (Heat Pain Tolerance Threshold, PTT), 압력통각역치 (Pressure Pain Threshold, PPT)를 측정하였으며, 각기 다른 통각 역치 간의 상관관계와 측정 부위 별 통각 역치 간의 상관 관계를 분석하였다. CPT, HPT, PTT를 포함한 온도통각역치의 성별간 차이는 나타나지 않았다. 그러나 PPT는 여성이 남성에 비하여 모든 부위에서 유의하게 낮은 역치를 나타내었다. CPT, HPT, PTT를 포함한 세 가지의 온도통각역치들은 모든 측정 부위에서 약정도에서 강정도 (mild to high)의 상관관계를 나타내었다 (r= 0.324-0.754, p<0.05). PPT 값은 각각의 온도통각역치와 통계적으로 유의한 상관관계를 나타내지 않았다. 모든 측정 부위의 통각역치값들은 서로간에 약정도에서 강정도 (mild to high)의 상관관계를 나타내었다 (r= 0.284-0.878, p<0.05). 측두하악장애 환자의 온도통각역치와 열통각인내역치 사이에는 유의한 상관관계가 존재하나 온도통각역치와 압력통각역치 간에는 상관관계가 나타나지 않는 것이 관찰되었으며, 각기 다른 부위에서 측정된 통각역치 간에는 비교적 높은 상관관계가 나타났다.

• 한국산업보건학회지
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• 제21권3호
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• pp.168-176
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• 2011

Objectives: Hundreds of thousands of call center workers are wearing an acoustic device for their businesses, such as telemarketing and customer counseling, and the number of the workers are increasing sharply. Because call center workers always talk to dozens of customers over the headset, they would be placed under the state of a higher risk with their hearing ability. The purpose of this study is to investigate factors that affect the hearing thresholds for the call center workers. Methods: This study investigated hearing losses of 101 workers of 5 call centers in Korea by executing puretone audiometry and self-administered questionnaires. A cross table analysis was processed to compare gender differences between male and female. Male and female hearing thresholds were compared with the Students' t-test, and one-way ANOVA was conducted to observe the difference between non-occupational and occupational characteristics in 2, 3, 4, 6, and 8 kHz hearing thresholds for the female workers. Additionally, multiple regression analysis was conducted to find the factors that affect the 4 kHz hearing thresholds. Results and Conclusions: Male hearing thresholds were higher than those of female except for 8 kHz. In the group having an ear related disease, hearing threshold of male left ear was highly affected rather than that of female in 4 kHz. There were significant differences in the variables of alcohol drinking (2 kHz) and headset volume (8 kHz) in both ears. While this study does not show any significant factors that affect the hearing thresholds in the occupational characteristics, the gender and the previous ear related diseases, non-occupational characteristics, were found as the factors in 4 kHz. It is suggested that the more detailed survey be performed to identify the occupational factors that affect the hearing thresholds in the call center workers based on the result derived from this study.

• 전자공학회논문지A
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• 제32A권4호
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• pp.32-39
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• 1995

In this paper, a timer thresholds tuning algorithm is proposed, satisfying the required response time for traffic with time-critical applications and asynchronous traffic in FDDI network. Under light and medium load, priorities and timer thresholds play a minor role for medium access control. In these cases all quenes are served exhaustively with a ver high service probability and the packet loss probability approaches almost zero. Under overload condition, however, the performance of the FDDI Network is completely determined by the selection of the timer thresholds. The timer thresholds tuned by mathematical results is confirmed by simulation results using SIMAN/UNIX package. The allocation of guaranteed bandwidth can be controlled easily by tuning the timer thresholds according to the proposed rules.

• 대한임상전기생리학회지
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• 제7권1호
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• pp.23-27
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• 2009

Purpose : The purpose of this study was to examine the effects of different medium frequency currents on afferent fibers. Methods : Thirty healthy volunteers who had no known history of neurological disorders were equally assigned to one of three groups; 2500Hz, 4000Hz, and control and each group was applied to the left wrist in palmer cutaneous branch of radial nerve by different medium frequency currents for 15 min. We measured the changes of thresholds for tactile, two-point discrimination, and thresholds for pain. Results : The results showed that the medium frequency currents stimulation increased thresholds for tactile, two-point discrimination, and thresholds for pain. However, there is no statistically significant difference between group 2500Hz and group 4000Hz. Conclusion : This may explain thresholds for tactile, two-point discrimination, and thresholds for pain plain medium frequency currents stimulation inhibits the excitability of afferent fibers, but the effect of the frequency difference within medium frequency currents is not demonstrated.