• 한국환경과학회지
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• 제23권3호
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• pp.511-520
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• 2014

The MFFn(Mass first flush), EMCs(Event mean concentrations) and runoff loads were analyzed for various rainy events(monitoring data from 2011 to 2012) in transportation area(rail road in station). The pollutant EMCs by volume of stormwater runoff showed the BOD5 9.6 mg/L, COD 29.9 mg/L, SS 16.7 mg/L, T-N 3.271 mg/L, T-P 0.269 mg/L in the transportation areas(Railroad in station). The average pollutant loading by unit area of stormwater runoff showed the BOD5 $27.26kg/km^2$, COD $92.55kg/km^2$, SS $50.35kg/km^2$, T-N $10.13kg/km^2$ and T-P $10.13kg/km^2$ in the transportation areas. Estimated NCL-curve(Normalized cumulated-curve) was evaluated by comparison with observed MFFn. MFFn was estimated by varying n-value from 10% to 90% on the rainy events. The n-value increases, MFFn is closed to '1'. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good.

• 한국자동차공학회논문집
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• 제25권2호
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• pp.250-256
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• 2017

Automatic transmission(A/T) is one of a car's core components. The durability of A/T has an effect on the durability of the car. The input shaft of A/T passes the power directly from the engine, so the durability of the input shaft for A/T is likewise vital. In this study, the test method of the input shaft is considered and the load spectrum of A/T is analyzed to secure durability of the input shaft. The shape parameter, T-N curve of the input shaft torsional fatigue test are obtained for life evaluation and analysis. Results of this study can be used to get the basic background of the durability test for A/T components.

• 대한기계학회논문집A
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• 제39권12호
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• pp.1207-1212
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• 2015

진동리퍼는 암반의 파쇄와 리핑 작업을 동시에 하기 위해서 개발된 장비이며 기존의 암반 파쇄용 유압 브레이커와 작동 원리가 다르다 진동리퍼의 기진력을 투스로 전달하는 기어박스-생크 용접부는 매우 중요한 부분이며 진동리퍼의 기계적 건전성의 예측이 필수적이다. 본 연구는 생크소재 및 용접재료의 변화에 따른 접부의 피로수명 예측을 목적으로 하고 있다. 생크의 재료는 Hadox-hituf, AR 400을 사용하였고 접금속은 CSF-71T, CSF-81T를 사용하였다. 피로시험은 응력비 R=0에서 각 재료조건에 대해서 수행하였다. P-S-N 선도는 JSME-S002 규정에 맞춰 파괴확률 10%, 50%, 90%에 대해서 나타냈으며 수명 예측 식을 도출하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.840-842
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• 2000

DC모터의 T-N(토크-회전수)특성이 선형성을 갖는다는 사실은 널리 알려져 있다. 더욱이 인덕턴스가 작은 소형 모터의 경우에는 T-N특성이 거의 직선에 가깝게 된다. 그러나 대형모터일수록 인덕턴스가 커지므로 이 인덕턴스의 영향으로 T-N특성은 비선형의 곡선으로 변하게 된다. 이렇게 되면 모터의 출력은 직선으로 예측하였을 때 보다 실제적으로 작은 출력이 발생하게 된다. 따라서 일반적으로 DC모터를 설계할 때 T-N특성의 비선형화로 인한 출력의 감소현상을 고려하여 임의의 여유를 주고 설계하여 왔다. 그러나 효율적인 모터설계를 위하여서는 임의의 여유가 아닌, 이론적 계산에 의한 정확한 T-N특성의 곡선을 필요로 하게 된다. 하지만 아직까지 이를 위한 용이한 계산법은 마련되어 있지 않다. 따라서 본 논문에서는 matlab을 이용하여 DC모터의 비선형 T-N곡선의 계산법을 도출하여 그 방법을 제시하고자 한다.

• 한국안광학회지
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• 제5권2호
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• pp.151-155
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• 2000

칼라 렌즈 제작시 착색 시간에 따른 분광반사율을 측정하여 렌즈표면의 굴절률을 계산하였다. 착색 시간이 길수록 반사율과 굴절률은 커진다. 렌즈 표면에 착색물질이 포화상태가 될 때까지 굴절률은 시간에 따라 증가하였다. 시간에 따른 blue color 렌즈의 굴절률 변화 곡선은 Boltzmann 성장곡선을 따르며, 이때 $n_{min}$은 1.482. $n_{max}$는 1.497. $t_c=11.53$ 그리고 $d_0$ 등의 2.287 등의 parameter 값을 얻었다.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.115-125
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• 2014

We investigate dissociation of diatomic molecules and anions using density functional theory (DFT) and density-corrected density functional theory (DC-DFT). We scan the potential energy curve of CH, NH and NO neutral molecule and its anion with both DFT and DC-DFT (in form of Hartree-Fock DFT, HF-DFT) using various functionals. Using CCSD(T) results as reference, we perform the error decomposition scheme recently proposed by Kim et al. The results show while most neutrals are $functio{\acute{n}}al$ error $domi{\bar{n}}ating$ normal calculations, $CH^-$ and $NO^-$ anions are density-driven error dominating abnormal calculations. In case of $NH^-$, traditional DFT goes to a wrong dissociation limit indicating abnormality, but both HF-DFT and CCSD(T) results need further investigation due to the kinks on the curve.

• 한국물환경학회지
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• 제29권6호
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• pp.762-776
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• 2013

Load duration curve was applied to determine important water quality parameter control term for improvement of Paldang lake water quality. Load duration curve was analyzed with long term data from 1985 to 2012 including water quality, flow rate and climate state of Paldang water environment. From the result of flow rate patterns of paldang lake, differences between high and low flow rate of each year showed tendency of increase because rainfall characteristics of paldang lake watershed were changed by climate exchange. Both of land use state of upper Paldang lake watershed and number of limit excess from load duration curve indicated that seasonal action related with land use such as agricultural fertilizer distribution in upper watershed affected Paldang lake water quality. So focused BOD (biological oxygen demand) management during spring season from march to June is required to control organic materials in Paldand lake. The main affecting factor of TOC (total organic carbon) increase in Paldang lake was initial rainfall after march. T-N (total nitrogen) kept increasing during research period, so enhancement of T-N standard is needed to T-N control. Initial rainfall and increase of temperature during spring season from March to June showed a positive correlation with TP (total phosphorus) and Chl-a, respectively.

• 한국환경과학회지
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• 제28권10호
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• pp.873-885
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• 2019

In this study, a load duration curve was applied to the Jangseongcheon, one of the tributaries of the Yeongsan River, to assess whether the target water quality was achieved. In addition, pollution of the water body was investigated to develop and suggest the optimal management time with respect to polluted flow sections and monthly conditions. The average flow rates of sections JS1 and JS2 were $0.25m^3/s$ and $1.08m^3/s$, respectively. The BOD and T-P for water-quality standards at JS1 were rated at II, whereas the COD and TOC were rated at III, thus indicating a fair level of water quality. By contrast, the BOD at JS2 was rated at III, the T-P at IV, and the TOC at V, indicating poor water quality in this section. The load duration curve was plotted using the actual flow data measured in eight-day intervals for eight years from 2011 to 2018 at locations JS1 and JS2 in the Jangsungcheon Basin. In an assessment using the load duration curve on whether the target water quality was met at location JS1, all of the water quality parameters (BOD, COD, TOC, T-N, T-P, and SS) satisfied the target water quality. By contrast, at location JS2, parameters COD, TOC, T-N, and T-P exceeded target values by more than 50%, indicating the target water quality was not met. The discharge loads of locations JS1 and JS2 were analyzed to identify the reasons the target water quality was exceeded. Results revealed that the land system contributed considerably. Furthermore, the discharge load of JS2 accounted for more than 80% of the load on the entire basin, excluding that of JS1. Therefore, the best method for restraining the inflow of pollutants into the stream near location JS2 must be applied to manage the water quality of the Jangsungcheon.

• 한국물환경학회지
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• 제26권6호
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• pp.903-909
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• 2010

The purpose of this study was evaluated on the applicability of Load Duration Curve Method (LDC Method) using HSPF watershed model and sampling data for efficient TMDLs in Korea. The LDC Method was used for assessment pollutant characteristics in watershed and water quality variation in each water flow level. Load Duration Curve is applied for judge the level of impaired water-body and can be estimated the impaired level by pollutant, such as BOD, T-N, and T-P in this study depending on variation of stream flow. As a result, BOD, T-P was usually exceed the standard value at low flow and dry hydrologic period. Improvement of effluent concentration from WWTP and riparian buffer protection zone are effective to improve the water quality. T-N showed the worst condition at mid-range hydrologic period and moist hydrologic period. Therefore, soil erosion control program and BMPs for non-point source pollution control is effective for recovery the water quality, which can be useful method for management of water quality in the plan of recovery water quality spontaneously. Applicability of LDC Method was evaluated in the Nakbon A watershed. However, we need to consider more detailed and accumulated data set such as accurate GIS data and detail pollution data, and WWTP discharge water quality data for accurate evaluation of watershed. Overall, The LDC Method is adequate for evaluation of watersheds characteristics, and its application is recommended for watershed management and TMDL Implementation.

• 사물인터넷융복합논문지
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• 제6권2호
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• pp.25-29
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• 2020

타원곡선 암호 알고리즘은 RSA 공개키 알고리즘에 비해 짧은 키의 길이와 적은 통신 부하 때문에 IoT 환경에서 인증용으로 많이 사용되고 있다. 타원곡선 암호 알고리즘의 핵심연산인 스칼라 곱셈이 안전하게 구현되지 않으면, 공격자가 단순 전력분석이나 차분 전력분석을 사용하여 비밀 키를 찾을 수 있다. 본 논문에서는 스칼라 난수화와 타원곡선점 가리기를 함께 적용하고, 연산의 효율성이 크게 떨어지지 않으며 전력분석 공격법에 대응하는 결합 난수 타원곡선 스칼라 알고리즘을 제안한다. 난수 r과 랜덤 타원곡선 점 R에 대해 변형된 Shamir의 두 배 사다리 알고리즘을 사용하여 타원곡선 스칼라 곱셈 kP = u(P+R)-vR을 계산한다. 여기에서 위수 n=2^l±c일 때, 2^lP=∓cP를 이용하여 l+20 비트 정도의 u≡rn+k(modn)과 ν≡rn-k(modn)를 구한다.