• Title/Summary/Keyword: threshold methods

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An Alternative Study of the Determination of the Threshold for the Generalized Pareto Distribution (일반화 파레토 분포에서 임계치 결정에 대한 대안적 연구)

  • Yoon, Jeong-Yoen;Cho, Jae-Beom;Jun, Byoung-Cheol
    • The Korean Journal of Applied Statistics
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    • v.24 no.5
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    • pp.931-939
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    • 2011
  • In practice, thresholds are determined by the two subjective assessment methods in a generalized pareto distribution of mean extreme function(MEF-graph) or Hill-graph. To remedy the problem of subjectiveness of these methods, we propose an alternative method to determine the threshold based on the robust statistics. We compared the MEF-graph, Hill-graph and our method through VaRs on the Korean stock market data from January 5, 1987 to August 3, 2009. As a result, the VaR based on the proposed method is not much different from the existing methods, and the standard deviation of VaR for our method was the smallest. The results show that our method can be a promising alternative to determine thresholds of the generalized pareto distributions.

Development of Rainfall Information Production Technology Using Optical Sensors (Estimation of Real-Time Rainfall Information Using Optima Rainfall Intensity Technique) (광학센서를 이용한 강우정보 생산기법 개발 (최적 강우강도 기법을 이용한 실시간 강우정보 산정))

  • Lee, Byung-Hyun;Kim, Byung-Sik;Lee, Young-Mi;Oh, Cheong-Hyeon;Choi, Jung-Ryel;Jun, Weon-Hyouk
    • Journal of Environmental Science International
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    • v.30 no.12
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    • pp.1101-1111
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    • 2021
  • In this study, among the W-S-R(Wiper-Signal-Rainfall) relationship methods used to produce sensor-based rain information in real time, we sought to produce actual rainfall information by applying machine learning techniques to account for the effects of wiper operation. To this end, we used the gradient descent and threshold map methods for pre-processing the cumulative value of the difference before and after wiper operation by utilizing four sensitive channels for optical sensors which collected rain sensor data produced by five rain conditions in indoor artificial rainfall experiments. These methods produced rainfall information by calculating the average value of the threshold according to the rainfall conditions and channels, creating a threshold map corresponding to the 4 (channel) × 5 (considering rainfall information) grid and applying Optima Rainfall Intensity among the big data processing techniques. To verify these proposed results, the application was evaluated by comparing rainfall observations.

The Clinical study on the change of pain after needle acupuncture and needle acupuncture combined herbal acupuncture therapy in the musculoskeletal disorder (근골격계질환에 있어서 침치료와 침과 약침복합치료 자극 후 통증의 변화)

  • Lim, Jeong-A;Kim, Sung-Nam;Lee, Sung-Yong;Lee, Sang-Kwan;Moon, Hyung-Cheol;Koo, Sung-Tae;Choi, Sun-Mi;Kim, Sung-Chul
    • Journal of Pharmacopuncture
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    • v.8 no.2
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    • pp.83-90
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    • 2005
  • Objective : This study was performed to compare needle acupuncture combined herbal acupuncture therapy with only needle acupuncture therapy in VAS and pain threshold. Methods : We used pressure algometer to evaluate the change of pain threshold before and after treatment. The numberical value of pressure algometer is obtained twice and averaged by identical acupuncturist. Visual analogue scale(VAS) was used to estimate the efficacy of needle acupuncture combined herbal acupuncture therapy. Result : The following results were obtained; 1. The significant difference in VAS was showed before and after treatment in only needle acupuncture therapy. 2. The significant difference in pain threshold and VAS was showed before and after treatment in needle acupuncture combined herbal acupuncture therapy. 3. In the pain threshold, the significant difference between only needle acupuncture and needle acupuncture combined herbal acupuncture therapy was not showed. 4. Needle acupuncture combined herbal acupuncture therapy showed the more effective change of VAS than only needle acupuncture therapy. Conclusions : In the pain control, needle acupuncture combined herbal acupuncture therapy is more effective than only needle acupuncture therapy.

Effects of Fixed-intensity and Varied-intensity Electroacupuncture in Pain and Sensory Threshold in Patients with Chronic Tension Headache (전침 자극 강도에 따른 만성 긴장성 두통 환자의 통증과 감각역치 변화 연구)

  • Kwon, You-Jung;Lee, Dong-Hua;Lee, Ung-In;Park, Kyung-Mo;Lee, Sang-Hoon
    • Journal of Acupuncture Research
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    • v.29 no.4
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    • pp.25-34
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    • 2012
  • Objectives : This study was conducted to investigate the effects of fixed-intensity and varied-intensity electroacupuncture in pain and sensory threshold concerning parameters visual analogue scale(VAS), brief pain inventory(BPI) and quantitative sensory testing(QST), among chronic tension headache patients. Methods : Thirty patients with chronic tension headache were randomly assigned to three groups and received different kinds of electroacupuncture at $ST_{36}$ and $ST_{37}$. Group A received fixed-intensity electroacupuncture(fixed-EA), group B received varied-intensity electroacupuncture (varied-EA), and group C received only acupuncture treatment without electrical stimulation as a control group. The intervention was given three times per week, and continued in two weeks. All the experiments were conducted blindly. Results : Fixed-EA group showed a significant decrease of VAS and BPI compared to the baseline measurement, while both varied-EA and control group did not. Of the parameters of QST, subtraction of heat pain threshold(HPT) and cold pain threshold(CPT) slightly increased in all groups, but this was not significant. Conclusions : These results suggest that fixed-EA reduce pain and improve quality of life in patients with chronic tension headache and that acupuncture may regulate patient's pain sensitivity through changing sensory threshold.

Correlations Among Threshold and Assessment for Salty Taste and High-salt Dietary Behavior by Age (연령별 짠맛 역치, 짠맛 미각판정치와 짜게 먹는 식행동과의 상관성 분석)

  • Jiang, Lin;Jung, Yun-Young;Lee, Yeon-Kyung
    • Korean Journal of Community Nutrition
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    • v.21 no.1
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    • pp.75-83
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    • 2016
  • Objectives: The purpose of this study was to analyze correlation thresholds and assessment for salty taste and high-salt dietary behaviors by age. Methods: A total of 524 subjects including 100 each of elementary school students, middle school students, college students, and elderly as well as 124 adults were surveyed for detection and recognition thresholds, salty taste assessments, and high-salt dietary behaviors. Results: Elementary students had a lower detection threshold (p<0.05) and recognition threshold (p<0.01) than did the other groups. Salty taste assessments were lowest among elementary students, followed by middle school students, while college students, adults, and elderly had higher assessment score (p<0.001). Elementary students had significantly lower scores for high-salt dietary behavior than did middle school students, college students, adults and elderly (p<0.001). Middle school students had higher scores for high-salt dietary behavior than did elementary school students and elderly (p<0.001) but no meaningful difference was found in dietary behavior scores between college students, adults, and elderly. There were positive correlations between high-salt dietary behavior and detection thresholds (p<0.001), recognition thresholds (p<0.001), and salty taste assessment (p<0.001). High-salt dietary behavior was more positively correlated with salty taste assessment than detection and recognition thresholds for salty taste. Conclusions: This study suggested that salty taste assessments were positively associated with scores for the detection and recognition thresholds and high-salt dietary behavior.

Application of Bimodal Histogram Method to Oil Spill Detection from a Satellite Synthetic Aperture Radar Image

  • Kim, Tae-Sung;Park, Kyung-Ae;Lee, Min-Sun;Park, Jae-Jin;Hong, Sungwook;Kim, Kum-Lan;Chang, Eunmi
    • Korean Journal of Remote Sensing
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    • v.29 no.6
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    • pp.645-655
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    • 2013
  • As one of segmentation techniques for Synthetic Aperture Radar (SAR) image with oil spill, we applied a bimodal histogram method to discriminate oil pixels from non-oil pixels. The threshold of each moving window was objectively determined using the two peaks in the histogram distribution of backscattering coefficients from ENVISAT ASAR image. To reduce the effect of wind speed on oil spill detection, we selected ASAR image which satisfied a limit of wind speeds for successful detection. Overall, a commonly used adaptive threshold method has been applied with a subjectively-determined single threshold. In contrast, the bimodal histogram method utilized herein produces a variety of thresholds objectively for each moving window by considering the characteristics of statistical distribution of backscattering coefficients. Comparison between the two methods revealed that the bimodal histogram method exhibited no significant difference in terms of performance when compared to the adaptive threshold method, except for around the edges of dark oil spots. Thus, we anticipate that the objective method based on the bimodality of oil slicks may also be applicable to the detection of oil spills from other SAR imagery.

Orofacial Thermal Quantitative Sensory Testing (QST): A Study of Healthy Korean Women and Sex Difference

  • Ahn, Sung-Woo;Kim, Ki-Suk
    • Journal of Oral Medicine and Pain
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    • v.40 no.3
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    • pp.96-101
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    • 2015
  • Purpose: Thermal sensory test as an essential part of quantitative sensory testing (QST) has been recognized as a useful tool in the evaluation of the trigeminal nerve function. Normative data in the orofacial region have been reported but the data on differences in the test site, sex and ethnicity are still insufficient. Thus, this study aimed to investigate the normal range of orofacial thermal QST data in the healthy Korean women, and assess sex difference of thermal perception in the orofacial regions. Methods: Thermal QST was conducted on 20 healthy women participants (mean age, 26.4 years; range, 21 to 34 years). The thermal thresholds (cold detection threshold, CDT; warm detection threshold, WDT; cold pain threshold, CPT; and heat pain threshold, HPT) were measured bilaterally at the 5 trigeminal sites (the forehead, cheek, mentum, lower lip and tongue tip). The normative thermal thresholds of women in the orofacial region were evaluated using one-way ANOVA and compared with the previously reported data from age- and site-matched 30 healthy men (mean age, 26.1 years; range, 23 to 32 years) using two-way ANOVA. One experienced operator performed the tests of both sexes and all tests were done in the same condition except the time variability. Results: Women showed significant site differences for the CDT (p<0.001), WDT (p<0.001), and HPT (p=0.047) in the orofacial region. The CDT (p<0.001) and the CPT (p=0.007) presented significant sex difference unlike the WDT and the HPT. Conclusions: The thermal sensory evaluation in the orofacial region should be considered in the context of site and sex and the normative data in this study could be useful for assessment of the sensory abnormalities in the clinical setting.

Quantitative Detection of Residual E. coli Host Cell DNA by Real-Time PCR

  • Lee, Dong-Hyuck;Bae, Jung-Eun;Lee, Jung-Hee;Shin, Jeong-Sup;Kim, In-Seop
    • Journal of Microbiology and Biotechnology
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    • v.20 no.10
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    • pp.1463-1470
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    • 2010
  • E. coli has long been widely used as a host system for the manufacture of recombinant proteins intended for human therapeutic use. When considering the impurities to be eliminated during the downstream process, residual host cell DNA is a major safety concern. The presence of residual E. coli host cell DNA in the final products is typically determined using a conventional slot blot hybridization assay or total DNA Threshold assay. However, both the former and latter methods are time consuming, expensive, and relatively insensitive. This study thus attempted to develop a more sensitive real-time PCR assay for the specific detection of residual E. coli DNA. This novel method was then compared with the slot blot hybridization assay and total DNA Threshold assay in order to determine its effectiveness and overall capabilities. The novel approach involved the selection of a specific primer pair for amplification of the E. coli 16S rRNA gene in an effort to improve sensitivity, whereas the E. coli host cell DNA quantification took place through the use of SYBR Green I. The detection limit of the real-time PCR assay, under these optimized conditions, was calculated to be 0.042 pg genomic DNA, which was much higher than those of both the slot blot hybridization assay and total DNA Threshold assay, where the detection limits were 2.42 and 3.73 pg genomic DNA, respectively. Hence, the real-time PCR assay can be said to be more reproducible, more accurate, and more precise than either the slot blot hybridization assay or total DNA Threshold assay. The real-time PCR assay may thus be a promising new tool for the quantitative detection and clearance validation of residual E. coli host cell DNA during the manufacturingprocess for recombinant therapeutics.

The Effects of Spiral Taping Theraphy-A Randomisation Controlled Trial

  • Choi, Sung-Hun;Ko, Kyoung-Mo;Kim, Kyung-Woon;Lee, Yoon-Kyung;Lim, Seong-Chul;Jung, Tae-Young;Lee, Kyung-Min;Hwang, Jae-Wok;Seo, Jung-Chul
    • Journal of Acupuncture Research
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    • v.23 no.2
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    • pp.165-172
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    • 2006
  • Objectives : This study was designed to estimate the effects of Spiral Taping theraphy on low back pain or neck pain patients by using pressure pain threshold, visual analogue scale(VAS), and range of motion(ROM). Methods : The patients were allocated into two groups by randomisation. Spiral Taping theraphy group consisted of 11 patients and acupuncture theraphy group consisted of 10 patients. The degree of improvement of neck pain was evaluated by pressure pain threshold, VAS, and ROM before treatment and after treatment. The patients were commonly treated with acupuncture theraphy. After acupuncture Spiral Taping theraphy was peformed in Spiral Taping theraphy group. Results : Pressure pain threshold and VAS were significantly different between two groups. In Spiral Taping theraphy group the pressure pain threshold of the all points was significantly increased and VAS was significantly decreased than control group. But there was no significant difference between the two groups in ROM. Conclusion : The effectiveness of Spiral Taping theraphy on low back pain and neck pain patients was shown through pressure algometer and VAS. These imply that Spiral Taping theraphy may be useful for on low back pain or neck pain. Further study is needed about Spiral Taping theraphy.

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The Clinical Effects of Heating-conduction Acupuncture Therapy with General Acupuncture Therapy for Lateral Ligament Injury Induced by Ankle Sprain Grade II (전열침(傳熱鍼)과 일반 침의 병행치료가 발목 염좌로 인한 외측인대 2도 손상에 미치는 임상적 효과)

  • Jahng, Sun-Jeong;Jang, Hyo-Kil;Heo, Dong-Seok
    • Journal of Korean Medicine Rehabilitation
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    • v.21 no.4
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    • pp.191-203
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    • 2011
  • Objectives: The purpose of this study is to investigate the clinical effects of heating-conduction therapy on lateral ligament injury induced by ankle sprain grade II. Methods: The 67 outpatients who were diagnosed as ankle sprain grade II were performed heating-conduction acupuncture therapy on lateral ligament injury. To evaluate the efficiency of heating-conduction acupuncture therapy, pain threshold with pressure algometer and visual analogue scale(VAS) were applied pretreatment and after 1st, 2nd treatment. Results: 1. The pain threshold and VAS score after 1st and 2nd treatment with an isolated injury of the anterior talofibular ligament showed statistically significant improvement compared with pretreatment. 2. The VAS score after 1st and 2nd treatment with an combined injury to the anterior talofibular and the calcaneofibular ligament showed statistically significant improvement compared with pretreatment. 3. The VAS score after 1st and 2nd treatment with an combined injury to the anterior talofibular, calcaneofibular and posterior talofibular ligament showed statistically significant improvement compared with pretreatment. 4. After 1st and 2nd treatment on the posterior talofibular ligament and after 2nd treatment on the anterior taofibular and calcaneofibular ligament with an combined injury to the anterior talofibular, calcaneofibular and posterior talofibular ligament the pain threshold showed statistically significant improvement compared with pretreatment. 5. Between isolated injury and combined injury of lateral ligament, the difference in pain threshold and VAS score was not statistically significant. Conclusions: Heating-conduction acupuncture therapy has clinical effects of pain reduction on patient with an isolated injury and combined injury of lateral ligament induced by ankle sprain grade II.