• 전기학회논문지
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• 제60권2호
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• pp.285-292
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• 2011

DC traction power system is operated ungrounded so that minimize the stray current. Because the stray current is still present, a rail potential is increased. The ground faults in the DC railway systems are usually detected by a potential relay(64P). Moreover, if the rail potential goes high in the ordinary operating state because of the traction load, the potential relay would be maloperated. A presented protective relaying algorithm that can identify exactly the faulted region and can distinguish a ground fault from the potential rising of the rail is presented in this paper. This paper presents simulation technique that is very similar to the real operation situation using PSCAD/EMTDC.

• 대한원격탐사학회지
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• 제23권3호
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• pp.189-198
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• 2007

Introduction of lidar technology have contributed to a wide range of applications in generating quality surface models. Accordingly, because of the importance of terrain surface models in mapping applications, rigorous studies have been performed to extract ground points from a lidar data point cloud. Although most filters have been shown abilities to extract ground points with their parameters tuned, however, most experiments revealed that there are certain limitations in optimizing filter parameters and the correction of remaining misclassified points is not straightforward. In this study, therefore, a method to improve the quality of filtered lidar data is proposed, which exploits neighboring surface properties arising between immediate neighbors. The method comprises a sequence of procedures which can reduce commission and omission errors. Commission errors occurring in low-rise objects are reduced by utilizing morphological operations. On the other hand, omission errors are reduced by adding missing ground points around step edges. Experimental results show that the qualities of filtered data can be improved considerably by the proposed method.

• 제어로봇시스템학회논문지
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• 제21권3호
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• pp.210-216
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• 2015

This paper proposes a method to determine vehicle driving state using the driving characteristics index. This index is a quantitative value to classify the driving state of a vehicle with its velocity and heading angle in that instant. It can classify driving state into straight driving, lane changing driving and curve driving in real time. In addition, the number of positional information is movably set up by designed region of interest. The proposed index is expressed on the stable driving states. Each driving state has characteristic tendency, and is compared with index distributional areas. The proposed method is verified by the actual driving experiment on the KATECH proving ground.

• Ocean and Polar Research
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• 제41권1호
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• pp.19-34
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• 2019

The present study obtained universal mathematical models of all elements and characteristics regarding hook and line fishing systems. To describe the hook and line fishing systems on site we used three kinds of coordinate systems: the earth based coordinate system, natural coordinate system, and flow (velocity) coordinate system. Mathematical models presented in this article allow us to define the shape of the fishing gear, the tension of the rope at different points, hydrodynamic resistance, diameter of the hook's wire, immersion depth of the fishing hooks, distance from hooks to the ground and the required lifting force of the floats. These models allow for the performance of computer simulations regarding any kinds of hook and line gears in still water or water where flow occurs.

• 대한토목학회논문집
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• 제31권1C호
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• pp.53-63
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• 2011

본 논문은 터널굴착으로 인해 발생된 인접지반에서의 지반변위가 구조물에 미치는 영향을 지반조건(느슨한 모래, 조밀한 모래, 연약한 점토, 단단한 점토) 및 시공조건(지반손실량)을 달리하면서 지반-구조물 상호작용이 고려된 상태에서 조사한 것이다. 터널굴착에 의해 발생된 지반변위에 노출된 4층 블록식구조물이 서로 다른 지반조건 및 시공조건(지반손실량)에 노출될 때 발생되는 구조물 거동이 수치해석을 통해 조사되었다. 수치해석을 위한 구조물은 소요전단 및 인장강도 이상의 응력이 발생할 때 구조물에 실제크랙이 발생될 수 있도록 개별요소법(DEM)을 이용하여 모델링되었다. 터널굴착유발 지반변위에 노출된 4층 블록식구조물의 거동 및 손상정도가 지반변위의 크기에 따라 조사되었으며, 발생된 구조물의 거동 및 손상정도는 구조물에 발생한 변형, 크랙크기 및 분포를 고려하여 지반조건 및 시공조건(지반손실)별로 비교되었다. 뿐만 아니라, 다양한 지반조건 및 시공조건(지반손실)의 변화에 의해 구조물에 유발될 수 있는 손상정도의 크기가 손상도 예측기준 (Son and Cording, 2005)을 사용하여 제시되었다. 이러한 결과들은 향후 터널굴착으로 인해 유발되는 인접구조물의 손상을 제어하고 최소화하는데 필요한 정보를 제공할 것이다.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2343-2353
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• 2007

We report the application of time-dependent density functional theory (TDDFT) to the calculation of potential energy profile relevant to the excited state intramolecular proton transfer (ESIPT) processes in title molecules. The TDDFT single point energy calculations along the reaction path have been performed using the CIS optimized structure in the excited state. In addition to the Stokes shifts, the transition energies including absorption, fluorescence, and 0-0 transition are estimated from the TDDFT potential energy profiles along the proton transfer coordinate. The excited state TDDFT potential energy profile of SA and 3ASA resulted in very flat function of the OH distance in the range ROH = 1.0-1.6 A, in contrast to the relatively deep single minimum function in the ground state. Furthermore, we obtained very shallow double minima in the excited state potential energy profile of SA and 3ASA in contrast to the single minimum observed in the previous work. The change of potential energy profile along the reaction path induced by the substitution of electron donating groups (-NH2 and -OCH3) at different sites has been investigated. Substitution at para position with respect to the phenolic OH group showed strong suppression of excited state proton dislocation compared with unsubstitued SA, while substitution at ortho position hardly affected the shape of the ESIPT curve. The TDDFT results are discussed in comparison with those of CASPT2 method.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2271-2276
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• 2014

Second-order rate constants ($k_N$) have been measured spectrophotometrically for the reaction of 4-chloro-2-nitrophenyl X-substituted-benzoates (6a-6h) with a series of primary amines including hydrazine in 80 mol % $H_2O$/20 mol % DMSO at $25.0^{\circ}C$. The Br${\o}$nsted-type plot for the reaction of 4-chloro-2-nitrophenyl benzoate (6d) is linear with ${\beta}_{nuc}$ = 0.74 when hydrazine is excluded from the correlation. Such a linear Br${\o}$nsted-type plot is typical for reactions reported previously to proceed through a stepwise mechanism in which expulsion of the leaving group occurs in the rate-determining step (RDS). The Hammett plots for the reactions of 6a-6h with hydrazine and glycylglycine are nonlinear. In contrast, the Yukawa-Tsuno plots exhibit excellent linear correlations with ${\rho}_X$ = 1.29-1.45 and r = 0.53-0.56, indicating that the nonlinear Hammett plots are not due to a change in RDS but are caused by resonance stabilization of the substrates possessing an electron-donating group (EDG). Hydrazine is ca. 47-93 times more reactive than similarly basic glycylglycine toward 6a-6h (e.g., the ${\alpha}$-effect). The ${\alpha}$-effect increases as the substituent X in the benzoyl moiety becomes a stronger electron-withdrawing group (EWG), indicating that destabilization of the ground state (GS) of hydrazine through the repulsion between the nonbonding electron pairs on the two N atoms is not solely responsible for the substituent-dependent ${\alpha}$-effect. Stabilization of transition state (TS) through five-membered cyclic TSs, which would increase the electrophilicity of the reaction center or the nucleofugality of the leaving group, contributes to the ${\alpha}$-effect observed in this study.

• 수산해양기술연구
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• 제34권3호
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• pp.294-301
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• 1998

Towing performance of a midwater trawl system was examined aboard the training ship KAYA(2900ps) at the East Sea using the midwater trawl gear that had been designed and manufactured in accordance with the vessel. In this experiment, the trawl system data, the towing speed, the length and tension of the warp, net mouth height, and the depth of otter boards and net were measured and analyzed. The results are as follows: 1. In case of heaving in the warp with constant towing speed, the tension was suddenly increased and then again was reduced and after returned to the original steady state tension. At this time, net height was reduced a bit by ascension of ground rope, but returned to it’s original value. In the case where the warp was paid out, the tension was suddenly decreased and after increased and then returned to the tension of the original state, and the net height was greatly increased instantly by the sinking of the ground rope and then returned to the steady state 2. In the case of increased towing speed mm constant warp length, the tension was increased, and reducing the net height, the gear depth was decreased. On the other hand, in the case where towing speed was reduced, the tension was reduced and the gear depth and net height was increased. 3. Otter boards show a swing motion in the scope of 5~ 10m continuously. Otter boards responded to the state change of the trawl system at first, and then the motion of the net appeared. 4. The depth of net center was about 20m deeper than that of the otter boards, it shows about 0.4 times the warp length at the 4knots towing speed.

• Asian-Australasian Journal of Animal Sciences
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• 제15권8호
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• pp.1186-1190
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• 2002

One hundred and twenty nine primiparous sows were used to determine the effects of alternative processing procedures and feeding systems on the nutritional value of sorghum grain-based diets for lactating sows. Treatments were a ground sorghum control, steam-flaked sorghum and extruded sorghum fed in meal form and the ground sorghum control given as pellets or gruel (1:1 ratio of water and feed on a volume:volume basis). Average daily feed intake was greater for sows fed pelleted and gruel diet forms than sow fed the diets with steam-flaked and extruded sorghum (p<0.04). However, no differences occurred in sow weight or backfat losses among the treatments (p>0.14). Number of pigs weaned and livability rates were similar among treatments except that steam-flaked sorghum supported greater litter weight gains than extruded sorghum (p<0.02). Apparent digestibilities of DM, N and GE in sows fed steam-flaked and extruded sorghum were greater (p<0.001) than in sows fed pelleted or gruel diets. Of the various treatments, sows fed extruded sorghum tended to have the highest digestibilities of DM, N and GE, and lowest excretions of DM and N in the faeces. Severity of ulceration was not significantly affected by treatments (p>0.35), but keratinization was greatest for sows fed extruded sorghum (p<0.01). In conclusion, the alternative processing methods (steam-flaking and extrusion) and feeding system (pellets and gruel) had little effect on sow and litter performance. However, nutrient digestibilities were improved for all treatments that involved heating (steam flaking, extrusion and pelleting) and, thus, these treatments resulted in less fecal excretion of DM and N.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2877-2882
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• 2013

Second-order rate constants ($k_{Ox^-}$) have been measured spectrophotometrically for nucleophilic substitution reactions of 4-nitrophenyl X-substituted-cinnamates (7a-7e) and Y-substituted-phenyl cinnamates (8a-8e) with butane-2,3-dione monoximate ($Ox^-$) in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. The Hammett plot for the reactions of 7a-7e consists of two intersecting straight lines while the Yukawa-Tsuno plot exhibits an excellent linearity with ${\rho}_X$=0.85 and r=0.58, indicating that the nonlinear Hammett plot is not due to a change in the rate-determining step but is caused by resonance stabilization of the ground state (GS) of the substrate possessing an electron-donating group (EDG). The Br${\o}$nsted-type plot for the reactions of Y-substituted-phenyl cinnamates (8a-8e) is linear with ${\beta}_{lg}$ = -0.64, which is typical of reactions reported previously to proceed through a concerted mechanism. The ${\alpha}$-nucleophile ($Ox^-$) is more reactive than the reference normal-nucleophile ($4-ClPhO^-$). The magnitude of the ${\alpha}$-effect (i.e., the $k_{Ox^-}/k_{4-ClPhO^-}$ ratio) is independent of the electronic nature of the substituent X in the nonleaving group but increases linearly as the substituent Y in the leaving group becomes a weaker electron-withdrawing group (EWG). It has been concluded that the difference in solvation energy between $Ox^-$ and $4-ClPhO^-$ (i.e., GS effect) is not solely responsible for the ${\alpha}$-effect but stabilization of transition state (TS) through a cyclic TS structure contributes also to the Y-dependent ${\alpha}$-effect trend (i.e., TS effect).