• Title/Summary/Keyword: method optimization

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Signal Timing Calculation Model of Transit Signal Priority using Shockwave Theory (충격파 이론을 이용한 대중교통 우선신호의 신호시간 산정모형)

  • Park, Sang Sup;Cho, Hye Rim;Kim, Youngchan;Jeong, Youngje
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.4
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    • pp.897-905
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    • 2015
  • This research suggested the traffic signal calculation model of active transit signal priority using a shockwave model. Using this signal priority timing optimization model, the shockwave area is computed under the condition of Early Green and Green Extension among active transit signal priority techniques. This study suggested the speed estimation method of backward shockwave using average travel time and intersection passing time. A shockwave area change is calculated according to signal timing change of transit signal priority. Moreover, this signal timing calculation model could determine the optimal signal priority timings to minimize intersection delay of general vehicles. A micro simulation analysis using VISSIM and its user application model ComInterface was applied. This study checked that this model could calculate the signal timings to minimize intersection delay considering saturation condition of traffic flow. In case studies using an isolated intersection, this study checked that this model could improve general vehicle delay of more over ten percentage as compared with equality reduction strategy of non-priority phases. Recently, transit priority facilities are spreading such as tram, BRT and median bus lane in Korea. This research has an important significance in that the proposed priority model is a new methodology that improve operation efficiency of signal intersection.

Calibration of WASP7 Model using a Genetic Algorithm and Application to a Drinking Water Resource Reservoir (유전알고리즘을 이용한 WASP7 모형의 보정과 상수원 저수지에 대한 적용)

  • Bae, Sang-Mok;Cho, Jae-Heon
    • Journal of Environmental Impact Assessment
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    • v.23 no.6
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    • pp.432-444
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    • 2014
  • When the water quality modelling is done with a manual calibration, it is possible that the researcher's opinion may affect the objectivity of the research. Hence, the role of the automatic calibration is highly important. This research applies a technique to automatically calibrate the water quality parameters by implementing an optimization method. This involves estimating the optimum water quality parameters targeting influential parameters towards the lake's BOD, DO, Phosphorus, Nitrogen and Phytoplankton. To accurately calculate the water temperature and hydraulic characteristics of a deep, stratifying lake, EFDC, a 3-dimensional hydraulic model which can be linked to the WASP7 was applied. With EFDC, the segment of the lake is formed and utilized as an input data of the WASP7. For the calibration of the water quality parameters of the WASP7, an influence coefficient algorithm and a genetic algorithm was applied. Of the five water quality variables for calibration, the normalized residuals of the observed and calculated values of DO, TN, CBOD were relatively small and the three water quality variables were calibrated properly. Yet the accuracy of the calibration of TP and Chl-a was relatively low.

Tencel Dyeing by Natural Indigo Prepared from Dyer's Knotweed (천연인디고를 이용한 텐셀직물의 염색)

  • Shin, Youn-Sook;Son, Kyung-Hee;Yoo, Dong-Il
    • Journal of the Korean Society of Clothing and Textiles
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    • v.32 no.12
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    • pp.1963-1970
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    • 2008
  • Natural indigo dye in powder form was prepared by modifying traditional Niram method, using $Ca(OH)_2$ instead of baked oyster powder for precipitating indigo dye. The prepared dye was applied to dyeing Tencel fabrics to investigate the effect of experimental conditions for the optimization of dyeing process. The indigo dye powder contained 15.2%(w/w) of indigo content and 0.757%(w/w) of indirubin content on the basis of HPLC analysis. Maximum dye uptake was obtained at $60^{\circ}C$ for 20min. Almost saturated dye uptake was obtained at 2g/L of sodium hydrosulfite concentration up to 4g/L of indigo dye and then slowly increased for further increase of sodium hydrosulfite. Whereas at higher indigo dye concentration(8g/L) more than 3g/L of reducing agent concentration was required for obtaining the maximum dye uptake. At the same indigo dye and reducing agent concentration, K/S value of the sample dyed without sodium hydroxide(pH 5.75) was 15.19, much higher than one dyed in alkaline condition(K/S 5.76). There was no difference in colorfastness ratings among samples with different color strength. However, more fading was occurred for the sample with low color strength.

Optimization of Culture Conditions for Maintaining Pig Muscle Stem Cells In Vitro

  • Choi, Kwang-Hwan;Yoon, Ji Won;Kim, Minsu;Jeong, Jinsol;Ryu, Minkyung;Park, Sungkwon;Jo, Cheorun;Lee, Chang-Kyu
    • Food Science of Animal Resources
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    • v.40 no.4
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    • pp.659-667
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    • 2020
  • Muscle stem cells isolated from domestic animals, including cows and pigs, were recently spotlighted as candidates for the production of alternative protein resources, so-called cultured meat or lab-grown meat. In the present study, we aimed to optimize the in vitro culture conditions for the long-term expansion of pig muscle stem cells via the screening of various signaling molecules. Pig muscle stem cells were collected from the biceps femoris muscles of 3-d-old crossbred pigs (Landrace×Yorkshire×Duroc, LYD) and cultured in minimum essential medium-based growth media. However, the pig muscle stem cells gradually lost their proliferation ability and featured morphologies during the long-term culture over two weeks. To find suitable in vitro culture conditions for an extended period, skeletal muscle growth medium-2, including epidermal growth factor (EGF), dexamethasone, and a p38 inhibitor (SB203580), was used to support the stemness of the pig muscle stem cells. Interestingly, pig muscle stem cells were stably maintained in a long-term culture without loss of the expression of myogenic marker genes as determined by PCR analysis. Immunostaining analysis showed that the stem cells were capable of myogenic differentiation after multiple passaging. Therefore, we found that basal culture conditions containing EGF, dexamethasone, and a p38 inhibitor were suitable for maintaining pig muscle stem cells during expanded culture in vitro. This culture method may be applied for the production of cultured meat and further basic research on muscle development in the pig.

Enhancing Robustness of Floor Vibration Control by Using Asymmetric Tuned Mass Damper (비대칭 동조질량감쇠기를 활용한 바닥진동제어의 강건성 향상 방안)

  • Ko, A Ra;Lee, Cheol Ho;Kim, Sung Yong
    • Journal of Korean Society of Steel Construction
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    • v.26 no.3
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    • pp.177-189
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    • 2014
  • When floor vibration problems occur in existing buildings, TMD (tuned mass damper) can be a viable alternative to resolving the problem. Only when TMD has been exactly tuned to the natural frequency of the floor, it can control the vibration as intended in design. However, TMD gets inefficient in the situation where the natural frequency changes as a result of the uncontrollable variation of the floor mass weight. This physical phenomenon is often called as TMD-off-tuning. This study proposes asymmetric TMD for enhancing the robustness of floor vibration control against uncertain natural frequencies. The proposed TMD features two asymmetric linear springs such that the floor vibrational energy can be dissipated through both the translational and rotational motion. An easy-to-use graphical optimization method was developed in this study. The asymmetric TMD proposed outperformed in vibration control by 28% compared to that of conventional TMD. The robustness of asymmetric TMD of this study was two times higher than that of conventional TMD.

Application of Ant System Algorithm on Parcels Delivery Service in Korea (국내택배시스템에 개미시스템 알고리즘의 적용가능성 검토)

  • Jo, Wan-Kyung;Rhee, Jong-Ho
    • Journal of Korean Society of Transportation
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    • v.23 no.4 s.82
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    • pp.81-91
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    • 2005
  • The Traveling Salesman Problem(TSP) is one of the NP-complete (None-deterministic Polynomial time complete) route optimization problems. Its calculation time increases very rapidly as the number of nodes does. Therefore, the near optimum solution has been searched by heuristic algorithms rather than the real optimum has. This paper reviews the Ant System Algorithm(ANS), an heuristic algorithm of TSP and its applicability in the parcel delivery service in Korea. ASA, which is an heuristic algorithm of NP-complete has been studied by M. Dorigo in the early 1990. ASA finds the optimum route by the probabilistic method based on the cumulated pheromone on the links by ants. ASA has been known as one of the efficient heuristic algorithms in terms of its calculation time and result. Its applications have been expanded to vehicle routing problems, network management and highway alignment planning. The precise criteria for vehicle routing has not been set up in the parcel delivery service of Korea. Vehicle routing has been determined by the vehicle deriver himself or herself. In this paper the applicability of ASA to the parcel delivery service has been reviewed. When the driver s vehicle routing is assumed to follow the Nearest Neighbor Algorithm (NNA) with 20 nodes (pick-up and drop-off places) in $10Km{\times}10Km$ service area, his or her decision was compared with ASA's one. Also, ASA showed better results than NNA as the number of nodes increases from 10 to 200. If ASA is applied, the transport cost savings could be expected in the parcel delivery service in Korea.

Optimization of Lipase-Catalyzed Production of Structured Lipids from Canola Oil Containing Similar Composition of Triacylglycerols to Cocoa Butter (Canola Oil로부터 코코아버터와 유사한 Triacylglycerol 조성을 가진 재구성지질의 효소적 합성 최적화 연구)

  • Moon, Jun-Hee;Lee, Jeung-Hee;Shin, Jung-Ah;Hong, Soon-Taek;Lee, Ki-Teak
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.10
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    • pp.1430-1437
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    • 2011
  • Synthesis conditions of cocoa butter equivalents were optimized using the response surface method (RSM) by interesterification of canola oil (Ca), palmitic ethyl ester (PEE), and stearic ethyl ester (StEE). The reaction was catalyzed by immobilized lipase (Lipozyme TLIM) from Thermomyces lanuginosa to produce structured lipids containing a composition of triacylglycerols similar to cocoa butter. Reaction conditions were optimized using D-optimal design with the three reaction factors of the substrate molar ratio of canola oil to palmitic ethyl ester and stearic ethyl ester (Ca : PEE : StEE=1:1:3, 1:1.66:5, 1:2:6, 1:2.33:7, 1:3:9, $X_1$), enzyme ratio (2~6%, $X_2$), and reaction time (30~270 min, $X_3$). The optimal conditions that minimized acyl-migration while maximizing 1-palmitoyl-2-oleoyl-3-stearoyl glycerol (POS), 1,3-distearoyl-2-oleoyl glycerol (SOS), and 1,3-dipalmitoyl-2-oleoyl glycerol (POP) were predicted, resulting in Ca : PEE : StEE=1:3:9, 6% of enzyme ratio, and 40 min of reaction time. The reaction product of structured lipids was synthesized again under the same conditions, showing 10.43 area% of acyl-migration, 25.31 area% of POS/PSO, 19.79 area% of SOS, and 11.22 area% of POP.

Analysis of Operational Status the Landscape Committee by Comparing before and after the Revision of Landscape Law -Focused on Deajeon City- (경관법 개정 전·후 비교를 통한 경관위원회 운영 실태 분석 -대전광역시 사례를 중심으로-)

  • Kang, Hyun-Wook;Eo, Sang-Jin;Ryu, Kyung-Moo;Kim, Young-Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.594-600
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    • 2018
  • Landscape law was enacted in 2007 after the development of the Korea Planning Support System (KOPSS) in 2006. In addition, KOPSS was utilized by many local governments to improve reliability and optimization in 2010. In 2014, landscape law was fully revised, and it is likely to have a considerable impact on municipal ordinances and deliberations, which may have a considerable effect on the results of landscape reviews. This paper presents an analysis and verification of changes in the subject of deliberation by the amendment of the law and system, the method of deliberation, the composition of the scenery committee, and the introduction of KOPSS. We also propose a direction for improving the landscape deliberation system. As a result, the change of the number of deliberation items repeatedly increased and decreased due to the change of the deliberation subject and deliberation management according to the total revision of the resultant laws and institutions. In sum, it affected the deliberation decisions.

Wavelet Thresholding Techniques to Support Multi-Scale Decomposition for Financial Forecasting Systems

  • Shin, Taek-Soo;Han, In-Goo
    • Proceedings of the Korea Inteligent Information System Society Conference
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    • 1999.03a
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    • pp.175-186
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    • 1999
  • Detecting the features of significant patterns from their own historical data is so much crucial to good performance specially in time-series forecasting. Recently, a new data filtering method (or multi-scale decomposition) such as wavelet analysis is considered more useful for handling the time-series that contain strong quasi-cyclical components than other methods. The reason is that wavelet analysis theoretically makes much better local information according to different time intervals from the filtered data. Wavelets can process information effectively at different scales. This implies inherent support for multiresolution analysis, which correlates with time series that exhibit self-similar behavior across different time scales. The specific local properties of wavelets can for example be particularly useful to describe signals with sharp spiky, discontinuous or fractal structure in financial markets based on chaos theory and also allows the removal of noise-dependent high frequencies, while conserving the signal bearing high frequency terms of the signal. To data, the existing studies related to wavelet analysis are increasingly being applied to many different fields. In this study, we focus on several wavelet thresholding criteria or techniques to support multi-signal decomposition methods for financial time series forecasting and apply to forecast Korean Won / U.S. Dollar currency market as a case study. One of the most important problems that has to be solved with the application of the filtering is the correct choice of the filter types and the filter parameters. If the threshold is too small or too large then the wavelet shrinkage estimator will tend to overfit or underfit the data. It is often selected arbitrarily or by adopting a certain theoretical or statistical criteria. Recently, new and versatile techniques have been introduced related to that problem. Our study is to analyze thresholding or filtering methods based on wavelet analysis that use multi-signal decomposition algorithms within the neural network architectures specially in complex financial markets. Secondly, through the comparison with different filtering techniques results we introduce the present different filtering criteria of wavelet analysis to support the neural network learning optimization and analyze the critical issues related to the optimal filter design problems in wavelet analysis. That is, those issues include finding the optimal filter parameter to extract significant input features for the forecasting model. Finally, from existing theory or experimental viewpoint concerning the criteria of wavelets thresholding parameters we propose the design of the optimal wavelet for representing a given signal useful in forecasting models, specially a well known neural network models.

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Depth Upsampling Method Using Total Generalized Variation (일반적 총변이를 이용한 깊이맵 업샘플링 방법)

  • Hong, Su-Min;Ho, Yo-Sung
    • Journal of Broadcast Engineering
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    • v.21 no.6
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    • pp.957-964
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    • 2016
  • Acquisition of reliable depth maps is a critical requirement in many applications such as 3D videos and free-viewpoint TV. Depth information can be obtained from the object directly using physical sensors, such as infrared ray (IR) sensors. Recently, Time-of-Flight (ToF) range camera including KINECT depth camera became popular alternatives for dense depth sensing. Although ToF cameras can capture depth information for object in real time, but are noisy and subject to low resolutions. Recently, filter-based depth up-sampling algorithms such as joint bilateral upsampling (JBU) and noise-aware filter for depth up-sampling (NAFDU) have been proposed to get high quality depth information. However, these methods often lead to texture copying in the upsampled depth map. To overcome this limitation, we formulate a convex optimization problem using higher order regularization for depth map upsampling. We decrease the texture copying problem of the upsampled depth map by using edge weighting term that chosen by the edge information. Experimental results have shown that our scheme produced more reliable depth maps compared with previous methods.