• Title/Summary/Keyword: Level curve

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Compact implementations of Curve Ed448 on low-end IoT platforms

  • Seo, Hwajeong
    • ETRI Journal
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    • v.41 no.6
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    • pp.863-872
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    • 2019
  • Elliptic curve cryptography is a relatively lightweight public-key cryptography method for key generation and digital signature verification. Some lightweight curves (eg, Curve25519 and Curve Ed448) have been adopted by upcoming Transport Layer Security 1.3 (TLS 1.3) to replace the standardized NIST curves. However, the efficient implementation of Curve Ed448 on Internet of Things (IoT) devices remains underexplored. This study is focused on the optimization of the Curve Ed448 implementation on low-end IoT processors (ie, 8-bit AVR and 16-bit MSP processors). In particular, the three-level and two-level subtractive Karatsuba algorithms are adopted for multi-precision multiplication on AVR and MSP processors, respectively, and two-level Karatsuba routines are employed for multi-precision squaring. For modular reduction and finite field inversion, fast reduction and Fermat-based inversion operations are used to mitigate side-channel vulnerabilities. The scalar multiplication operation using the Montgomery ladder algorithm requires only 103 and 73 M clock cycles on AVR and MSP processors.

Development of Measure of Effectiveness (MOE) and Algorithm for Hazard Level at Curve Sections (곡선부 위험도 판정척도 및 알고리즘 개발)

  • Ha, Tae-Jun;Jeong, Jun-Hwa;Lee, Jeong-Hwan;Lee, Suk-Ki
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.5D
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    • pp.627-638
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    • 2008
  • At present, there is a no rational MOE for evaluating hazard level at curve sections. Therefore, this study focus on developing the MOE and algorithm for hazard level at curve sections. The scopes of this study limited to rural two-way roads. Actual data used is accident, geometric features, safety facilities of the selected sites at curve sections. In order to develop MOE for hazard level at curve sections, accident contributing factors were classified by road geometry, visual guidance facility, speed and driver factor. A relationship between the four factors mentioned and accidents was conducted. And, the MOE for hazard level at curve sections was derived from the previous relationship analysis, and the algorithm for hazard level was developed. Finally, worksheets were suggested based on the MOE and algorithm for road designers. These developed MOE and algorithm can be used to reduce serious accident contributing factors when designing roads and also, these will be used to determine an order of priority when reconstructing roads.

Determination of the Tension-Softening Curve of Concrete at Different Strength Level using Fictitious Crack Model (가상균열모델에 의한 강도 수준이 다른 콘크리트의 인장연화곡선 결정)

  • 오성진;박현재;김희성;진치섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.125-130
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    • 2002
  • The most important material parameters are fracture energy and the stress-crack opening displacement($\sigma$-w) curve to determine the behavior of concrete. Especially, the relationship between the $\sigma$-w curve is strongly important to determine the load-displacement curve of concrete that has a major influence on the fracture behavior of a concrete. In this paper, notched plain concrete beams with different strength level were tested under three-point bending and fracture energy, the load-deflection curve, and the load-crack mouth opening displacement(CMOD) curve were obtained from the experimental data. Also, the fictitious crack model(FCM) was applied to determine the load-deflection curve of notched plain concrete beams using various types of $\sigma$-w curve model proposed by Petersson and we compared experimental results with numerical ones carried out by Finite Element Method(FEM).

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Improvement of Low Water Level Rating Curve in Tidal River Taehwa (태화강 갑조부의 저수위 수위-유량곡선 개선)

  • Jo, Hong-Je;Hwang, Jae-Ho;Mun, Seong-Jun
    • Journal of Korea Water Resources Association
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    • v.33 no.5
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    • pp.635-645
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    • 2000
  • In tidal rivers, the river level, discharge and tide are interrelated. Therefore, the stage-discharge relation that takes no account of tidal effects is inaccurate. For the calculation of river discharge in low water level, this paper attempts to formulate a multiple regression equation of stage-discharge curve to calculate the river discharge in low water level with variables as river level and differences between sea level and river level. Numerical application were perfonned on Ulsan gaging station in Taehwa river, and the comparison with existing rating curve equation showed good applicability of this multiple regression equation.uation.

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Estimating the rating curve of irrigation canals in the Cheongju Sindae area

  • Mikyoung Choi;Inhyeok Song;Heesung Lim;Hansol Kang;Hyunuk An
    • Korean Journal of Agricultural Science
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    • v.51 no.1
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    • pp.79-86
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    • 2024
  • As the frequency and intensity of heavy rains increase, the vulnerability of agriculture to disasters also increases. Consequently, there is a need to improve flood and inundation predictions. To enhance the accuracy of inundation predictions, it is essential to monitor water level and discharge data within agricultural areas. This study was conducted to monitor water levels and rainfall in the Cheongju Sindae area from 2022 to 2023, and the data was utilized as input and validation data for agricultural inundation modeling. Four irrigation drainage canals were installed to a square-shaped concrete structure where the water level gauge is. It was then confirmed that the water level rises with rainfall. The flow velocities were monitored during periods of heavy rainfall. The rating curve, which estimates water level and flow velocity based on observations, was estimated using the software K-HQ. The resulting curve was presented with the Coefficient of Determination (R2). K-HQ was also used to calculate the equation for the rating curve, taking outliers into account at each data point. Outliers were extracted and the rating curve was recalculated. As the coefficient of determination of three out of four stations exceeded 0.95, the estimated rating curve may be considered reliable for discharge estimation. This study provides critical data for enhancing agricultural inundation modeling accuracy and drainage improvement projects.

Application Method of Logistic Regression Analysis for Annoyance Prediction Model Based on Predicted Noise Level (예측소음도를 이용한 어노이언스 예측모델을 위한 로지스틱 회귀분석의 적용방법)

  • Son, Jin-Hee;Lee, Kun;Choung, Tae-Ryang;Chang, Seo-Il
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.6
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    • pp.555-561
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    • 2010
  • Predicted noise level has been used to assess the annoyance response since noise map was generalized and being the normal method to assess the environmental noise. Unfortunately using predicted noise level to derive the annoyance prediction curve caused some problems. The data have to be grouped manually to use the annoyance prediction curve. The aim of this paper is to propose the method to handle the predicted noise level and the survey data for annoyance prediction curve. This paper used the percentage of persons annoyed(%A) and the percentage of persons highly annoyed as the descriptor of noise annoyance in a population. The logistic regression method was used for deriving annoyance prediction curve. It is concluded that the method of dichotomizing data and logistic regression was suitable to handle the predicted noise level and survey data.

Wedge Shape Cage in Posterior Lumbar Interbody Fusion : Focusing on Changes of Lordotic Curve

  • Kim, Joon-Seok;Oh, Seong-Hoon;Kim, Sung-Bum;Yi, Hyeong-Joong;Ko, Yong;Kim, Young-Soo
    • Journal of Korean Neurosurgical Society
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    • v.38 no.4
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    • pp.255-258
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    • 2005
  • Objective : Lumbar lordotic curve on L4 to S1 level is important in maintaining spinal sagittal alignment. Although there has been no definite report in lordotic value, loss of lumbar lordotic curve may lead to pathologic change especially in degenerative lumbar disease. This study examines the changes of lumbar lordotic curve after posterior lumbar interbody fusion with wedge shape cage. Methods : We studied 45patients who had undergone posterior lumbar interbody fusion with wedge shape cage and screw fixation due to degenerative lumbar disease. Preoperative and postoperative lateral radiographs were taken and one independent observer measured the change of lordotic curve and height of intervertebral space where cages were placed. Segmental lordotic curve angle was measured by Cobb method. Height of intervertebral space was measured by averaging the sum of anterior, posterior, and midpoint interbody distance. Clinical outcome was assessed on Prolo scale at 1month of postoperative period. Results : Nineteen paired wedge shape cages were placed on L4-5 level and 6 paired same cages were inserted on L5-S1 level. Among them, 18patients showed increased segmental lordotic curve angle. Mean increased segmental lordotic curve angle after placing the wedge shape cages was $1.96^{\circ}$. Mean increased disc height was 3.21mm. No cases showed retropulsion of cage. The clinical success rate on Prolo's scale was 92.0%. Conclusion : Posterior lumbar interbody fusion with wedge shape cage provides increased lordotic curve, increased height of intervertebral space, and satisfactory clinical outcome in a short-term period.

A Study on Derivation of Rating Curve for Yangsan River (양산천 수위-유량 관계곡선의 유도에 관한 연구)

  • Lee, Y.H.;Lee, S.B.
    • Journal of Korean Port Research
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    • v.12 no.1
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    • pp.131-143
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    • 1998
  • This paper presents derivation of stage-discharge curve for Yangsan river. To derivate of stage-discharge lationship is one of the essential research areas in the water resource field. It provides reliable data a long term planning and hydrologic quantity on water resource development by quantitative analysis. The rating curve derivated through 15 discharge-observation on Yangsan river basin in 1997 has been estimated Q=1283.0262-1553.3158H+477.2702H2. According to the rating curve, the highest water level 2.6m, the limited water-level should be bound to the maximum of 2.6m. Before this research, stage-discharge curve of Yangsan river has not been developed, and only 15 discharge observation(hydrometry) has been carried out though this research. Therefore it seems necessary to collect observation data through a long term process to obtain a reliable rating curve equation.

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Review on the Relative Sea-level Changes in the Yellow Sea during the Late Holocene (한반도 서해안의 후기 홀로세 해수면 변동 곡선에 대한 검토)

  • Choi, Sung-Ja
    • Economic and Environmental Geology
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    • v.51 no.5
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    • pp.463-471
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    • 2018
  • In this paper, we review previous studies on the relative sea-level changes in the Yellow Sea during the Holocene to comprehensive understand the various research results. Currently, it is reported two theories : 1) the Holocene sea-level has never been higher than the present-day level; and 2) sea-level have reached highstand during mid-Holocene, followed by slow lowering to that of the present. The first theory yields a curve that is similar to a climate-change-related eustatic sea-level curve. However, in reality, most of the relative sea-level fluctuation resulted from land uplift or subsidence. The second theory yields a curve that is fairly coincident with a relative sea-level curve indicative of continental margins being located away from the ice sheets(i.e., far-field), and is considered as an effect of GIA(Glacio Isostatic Adjustment) and gravitational attraction. Based on detailed review of previous researches, we realized that they sourced the same papers, but obtained different results because they selectively chose and added the data. The data used to derive the second theory pertain to the northern Gunsan region, which is located within the western area of the Chugaryeong fault. Thus, we believe that the sea-level curve for the second theory is only representative of the area north of Gunsan, which is subject to GIA and tectonic deformation. Although the relative sea-level curve for the west coastal area is comparable to that for the far-field continental margin region, it is necessary to evaluate local tectonic activities as suggested by active seismicity in the west coastal area and the more than 400 faults currently existing in on the Korean Peninsula.

Extension of Rating Curve for High Water Level using Monte Carlo Simulation (MCS를 이용한 고수위 수위-유량관계곡선의 연장에 관한 연구)

  • Moon, Young-Il;Kim, Jong-Suk;Yoon, Sun-Kwon
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.683-686
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    • 2008
  • Flood damage has been increased due to the abnormal climate and extreme rainfall. So, quantitative and qualitative hydrologic data should be improved in oder to enhance accuracy of hydrologic forecast. However, research regarding hydrologic data have not been thorough enough. Therefore, in this study, monte carlo simulation was applied to rainfall runoff model to improve the reliability of runoff analysis and risk analysis. Rainfall-Stage-Discharge curve was developed as a consequence of MCS and it is possible to get correct rating curve for high water level.

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