• Title/Summary/Keyword: Optimal control methods

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Determining the Optimal Dose Prescription for the Planning Target Volume with Stereotactic Body Radiotherapy for Non-Small Cell Lung Cancer Patients

  • Liu, Xi-Jun;Lin, Xiu-Tong;Yin, Yong;Chen, Jin-Hu;Xing, Li-Gang;Yu, Jin-Ming
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.5
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    • pp.2573-2577
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    • 2016
  • Objective: The aim of this study was to determine a method of dose prescription that minimizes normal tissue irradiation outside the planning target volume (PTV) during stereotactic body radiotherapy (SBRT) for patients with non-small cell lung cancer. Methods: Previous research and patients with typical T1 lung tumors with peripheral lesions in the lung were selected for analysis. A PTV and several organs at risk (OARs) were constructed for the dose calculated; six treatment plans employing intensity modulated radiotherapy (IMRT) were produced, in which the dose was prescribed to encompass the PTV, with the prescription isodose level (PIL) set at 50, 60, 70, 80, 90 or 95% of the isocenter dose. Additionally, four OARs around the PTV were constructed to evaluate the dose received in adjacent tissues. Results: The use of higher PILs for SBRT resulted in improved sparing of OARs, with the exception of the volume of lung treated with a lower dose. Conclusions: The use of lower PILs is likely to create significant inhomogeneity of the dose delivered to the target, which may be beneficial for the control of tumors with poor conformity indices.

Multiple Path-planning of Unmanned Autonomous Forklift using Modified Genetic Algorithm and Fuzzy Inference system (수정된 유전자 알고리즘과 퍼지 추론 시스템을 이용한 무인 자율주행 이송장치의 다중경로계획)

  • Kim, Jung-Min;Heo, Jung-Min;Kim, Sung-Shin
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.8
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    • pp.1483-1490
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    • 2009
  • This parer is presented multiple path-planning of unmanned autonomous forklift using modified genetic algorithm and fuzzy inference system. There are a task-level feedback method and a method that path is dynamically replaned in realtime while the autonomous vehicles are moving by means of an optimal algorithm for existing multiple path-planning. However, such methods cause malfunctions and inefficiency in the sense of time and energy, and path-planning should be dynamically replanned in realtime. To solve these problems, we propose multiple path-planning using modified genetic algorithm and fuzzy inference system and show the performance with autonomous vehicles. For experiment, we designed and built two autonomous mobile vehicles that equipped with the same driving control part used in actual autonomous forklift, and test the proposed multiple path-planning algorithm. Experimental result that actual autonomous mobile vehicle, we verified that fast optimized path-planning and efficient collision avoidance are possible.

A Geometric Compression Method Using Dominant Points for Transmission to LEO Satellites

  • Ko, Kwang Hee;Ahn, Hyo-Sung;Wang, Semyung;Choi, Sujin;Jung, Okchul;Chung, Daewon;Park, Hyungjun
    • International Journal of Aeronautical and Space Sciences
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    • v.17 no.4
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    • pp.622-630
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    • 2016
  • In the operation of a low earth orbit satellite, a series of antenna commands are transmitted from a ground station to the satellite within a visibility window (i.e., the time period for which an antenna of the satellite is visible from the station) and executed to control the antenna. The window is a limited resource where all data transmission is carried out. Therefore, minimizing the transmission time for the antenna commands by reducing the data size is necessary in order to provide more time for the transmission of other data. In this paper, we propose a geometric compression method based on B-spline curve fitting using dominant points in order to compactly represent the antenna commands. We transform the problem of command size reduction into a geometric problem that is relatively easier to deal with. The command data are interpreted as points in a 2D space. The geometric properties of the data distribution are considered to determine the optimal parameters for a curve approximating the data with sufficient accuracy. Experimental results demonstrate that the proposed method is superior to conventional methods currently used in practice.

Feasibility Study on Long-Term Continuous Ethanol Production from Cassava Supernatant by Immobilized Yeast Cells in Packed Bed Reactor

  • Liu, Qingguo;Zhao, Nan;Zou, Yanan;Ying, Hanjie;Liu, Dong;Chen, Yong
    • Journal of Microbiology and Biotechnology
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    • v.30 no.8
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    • pp.1227-1234
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    • 2020
  • In this study, yeast cell immobilization was carried out in a packed bed reactor (PBR) to investigate the effects of the volumetric capacity of carriers as well as the different fermentation modes on fuel ethanol production. An optimal volumetric capacity of 10 g/l was found to obtain a high cell concentration. The productivity of immobilized cell fermentation was 16% higher than that of suspended-cell fermentation in batch and it reached a higher value of 4.28 g/l/h in repeated batches. Additionally, using this method, the ethanol yield (95.88%) was found to be higher than that of other tested methods due to low concentrations of residual sugars and free cells. Continuous ethanol production using four bioreactors showed a higher productivity (9.57 g/l/h) and yield (96.96%) with an ethanol concentration of 104.65 g/l obtained from 219.42 g/l of initial total sugar at a dilution rate of 0.092 h-1. Furthermore, we reversed the substrate-feed flow directions in the in-series bioreactors to keep the cells at their highest activity and to extend the length of continuous fermentation. Our study demonstrates an effective method of ethanol production with a new immobilized approach, and that by switching the flow directions, traditional continuous fermentation can be greatly improved, which could have practical and broad implications in industrial applications.

A Synthesis of New 2-Iminothiazolines and Their Antifungal Activities (II) (새로운 2-이미노티아졸린 유도체의 합성과 항균활성 (II))

  • Nam, Kee-Dal;Choi, Gyung-Ja;Cho, Kwang-Yun;Hahn, Hoh-Gyu
    • Applied Biological Chemistry
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    • v.41 no.6
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    • pp.471-476
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    • 1998
  • A synthesis and the screening of new 2-iminothiazolines (IV) of which structures are modified based on a lead compound, thiazoline for development of new agrochemical fungicide were described. Bromination of acetoacetanilides (I) which were prepared by the reaction of diketene with anilines gave the corresponding ${\gamma}-bromoacetoactanilide\;(II)$. Treatment of II with N-phenyl-N'-methyl thiourea (III) afforded IV, structure of which was confirmed by various spectroscopic methods. Antifungal activity of the new IV was tested against six kinds of typical plant diseases (in vivo). The IV with aromatic substituents showed remarkable activity against the Pyricuraria oryzae at 250 ppm in primary screening. The candidates with control value over 90% in primary screening were selected and further tested for second screening at lower concentrations. The IV which has an electron-withdrawing substituent such as halogen, especially fluorine in aryl group showed a higher activity as compared to those with electron-donating group and meta substituent was for optimal position.

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Malignancy Risk Scoring of Hydatidiform Moles

  • Pradjatmo, Heru;Dasuki, Djaswadi;Dwianingsih, Ery Kus;Triningsih, Ediati
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.6
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    • pp.2441-2445
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    • 2015
  • Background: Several risk factors leading to malignant transformation of hydatidiform moles have been described previously. Many studies showed that prophylactic chemotherapy for high risk hydatidiform moles could significantly decrease the incidence of malignancy. Thus, it is essential to discover a breakthrough to determine patients with high risk malignancy so that prophylactic chemotherapy can be started as soon as possible. Objectives: Development of a scoring system of risk factors as a predictor of hydatidiform mole malignant transformation. Materials and Methods: This research is a case control study with hydatidiform mole and choriocarcinoma patients as subjects. Multiple logistic regression was used to analyze the data. Odds ratios (OR), attributable at risk (AR : OR-1) and risk index ($ARx{\beta}$) were calculated for develoipment of a scoring system of malignancy risk. The optimal cut-off point was determined using receiver operating characteristic (ROC) curve. Results: This study analyzed 34 choriocarcinoma cases and 68 benign hydatidiform mole cases. Four factors significantly increased the risk of malignancy, namely age ${\geq}35$ years old (OR:4.41, 95%CI:1.07-16.09, risk index 5); gestational age ${\geq}$ 12weeks (OR:11.7, 95%CI:1.8-72.4, risk index 26); uterine size greater than the gestational age (OR:10.2, 95%CI:2.8-36.6, risk index 21); and histopathological grade II-III (OR:3.4, 95%CI:1.1-10.6, risk index 3). The lowest and the highest scores for the risk factors were zero and 55, respectively. The best cut-off point to decide high risk malignancy patients was ${\geq}31$. Conclusions: Malignant transformation of hydatidiform moles can be predicted using the risk scoring by analyzing the above four parameters. Score ${\geq}31$ implies high risk patients so that prophylactic chemotherapy can be promptly administered for prevention.

Current Treatments for Breast Cancer-Related Lymphoedema: A Systematic Review

  • Li, Lun;Yuan, Liqin;Chen, Xianyu;Wang, Quan;Tian, Jinhui;Yang, Kehu;Zhou, Enxiang
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.11
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    • pp.4875-4883
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    • 2016
  • Background and objective: Breast cancer-related lymphoedema (BCRL) is a disabling complication with long term impact on quality on life after breast cancer treatment. Its management remains a major challenge for patients and health care professionals; the goal of this overview was to summarize effects of different treatment strategies for patients with BCRL. Methods: A thorough search was undertaken to allow a systematic review or meta-analysis of treatments for BCRL. Two investigators independently selected studies and abstracted the data. Results: Combined physical therapy (CPT) with different combinations of surgery, oral pharmaceuticals, low-level laser therapy, weight reduction, mesenchymal stem cell therapy, kinesio tex taping, and acupuncture might be effective in reducing lymphoedema, but exercise demonstrated no obvious benefit. The results of direct comparisons showed CPT might be more effective than standard physiotherapy (ST). Manual lymphatic drainage (MLD) may not offer additional benefits to ST for swelling reduction, but could facilitate compression bandaging. MLD seemed to have similar effects with self-administered simple lymphatic drainage (SLD) or using an intermittent pneumatic compression pump (IPC). IPC might also not be associated with additional effectiveness for CPT. Efficacy of stem cell therapy vs. compression sleeve or CPT, as well as the effects of daflon and coumarin could not be established. Conclusion: Although many treatments for BCRL might reduce lymphoedema volume, their effects were not well established. The quality of many of the original studies in the included reviews was not optimal, so that in future randomized control trials are a high priority.

Effects of galactagogue herbal tea containing Chrysanthemum indicum as the main component on milk production in postpartum rats (감국을 주성분으로 하는 허브차의 투여가 출산 후 쥐의 유즙 생성 및 관련 호르몬 분비에 미치는 영향)

  • Choi, Jiyoung;Lee, Yunjung;Choi, Sunuk;Park, Eunju
    • Journal of Nutrition and Health
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    • v.53 no.5
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    • pp.445-451
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    • 2020
  • Purpose: Breastfeeding is the optimal method for feeding a newborn. But insufficient breast milk is the major reason why mothers give up breastfeeding. Herbal galactagogues have been used increasingly to treat postpartum hypogalactia. This study examined the effect of an herbal tea containing Chrysanthemum indicum, as the main ingredient, on milk production in lactating rats. Methods: The herbal tea contained C. indicum (27%), Foeniculum vulgare Mill (21%), Pimpinella anisum (18.2%), Carum carvi (16.1%), Urtica dioica (14.7%), and Gardenia jasminoides (3%). Sixteen lactating Sprague-Dawley (SD) rats were divided randomly into 2 groups, the normal control group (NC; n = 8), and the galactagogue herbal tea group (GHT; n = 8) for 7 days. Lactating rats were administered the decoction of an herbal galactagogue mixture by oral gavage or the same amount of distilled water and milk production was assessed by measuring the pups' weights during the suckling period. The blood concentrations of prolactin, cortisol, oxytocin levels and mammary gland tissues were examined to assess the effects of the galactagogue. Results: Milk production was 9.2% higher in the GHT group given the herbal tea than in the NC group and the difference was statistically significant. The cortisol level in the GHT group was 17.2% higher than the NC group. The herbal tea containing C. indicum increased the size of the alveoli epithelium cells and the mammary lobe. Conclusion: The present study revealed the potential of herbal tea containing C. indicum to enhance milk production in postpartum SD rats.

Optimal Treatment of Molasses Wastewater Using UASB Process (UASB 공정에 의한 당밀폐수의 최적처리 방안)

  • Huh, Kwan-Yong;Jeong, Eui-Geun;Chung, Yoon-Jin;Yoo, Sang-Keun
    • Journal of Korean Society of Water and Wastewater
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    • v.11 no.2
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    • pp.112-127
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    • 1997
  • The purpose of this study is to get optimum operating factors of Upflow Anaerobic Sludge Blanket (UASB) reactor by introducing methods that make it to reduce inhibition possible in each process wastewater treatment. The used substrates, concentrated corn starch liquid (CSL) wastewater, modified starch, filtering and decoloring wastewater, ion refining wastewater, and mixed wastewater including modified starch and not including modified starch, are generated from molasses process. The seeding sludge is the digested sludge that had been applied to molasses wastewater. Batch test to reduce the inhibition factors that might be existed in each wastewater was examined. Based on the this test, the optimum operating factors according to alkalinity and pH variation was studied through the continuous test using three 5.5 L UASB reactor. The first reactor added $NaHCO_3$ to control alkalinity. The hydraulic retention time (HRT) reduced to 8 hours and the organic loading rate increased gradually. The second reactor changed the pH of influent from 7.0 to 6.0 using NaOH. The third reactor was operated without changes to compare the above two reactors. As the result, the inhibition in concentrated CSL wastewater was removed by adding iron (II). When trace metals were added to mixed wastewater not including modified starch, the digestability by gas production rate increased to more fifty percentage than mixed wastewater that was not adding the trace metals. The reason that the inhibition did not decreased in spite of adding trace metals and nutrients was influenced by high concentration generated during the acid fermentation. The UASB reactors using the mixed wastewater with the most effective performance were operated as 500 mg/L as $CaCO_3$ alkalinity and 6.0 pH at steady state, and at this time, the gas production rates were 283 and 311mL gas/g $COD_{added}$. The COD removal rates were 84.7 and 86.3%, respectively.

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Radiation for persistent or recurrent epithelial ovarian cancer: a need for reassessment

  • Choi, Noorie;Chang, Ji Hyun;Kim, Suzy;Kim, Hak Jae
    • Radiation Oncology Journal
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    • v.35 no.2
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    • pp.144-152
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    • 2017
  • Purpose: The role of radiotherapy (RT) was largely deserted after the introduction of platinum-based chemotherapy, but still survival rates are disappointingly low. This study focuses on assessing the clinical efficacy of RT in relation to chemotherapy resistance. Materials and Methods: From October 2002 to January 2015, 44 patients were diagnosed with epithelial ovarian cancer (EOC) and treated with palliative RT for persistent or recurrent EOC. All patients received initial treatment with optimal debulking surgery and adjuvant platinum-based chemotherapy. The biologically effective dose (BED) was calculated with ${\alpha}/{\beta}$ set at 10. Ninety-four sites were treated with RT with a median BED of 50.7 Gy (range 28.0 to 79.2 Gy). The primary end-point was the in-field local control (LC) interval, defined as the time interval from the date RT was completed to the date any progressive or newly recurring disease within the RT field was detected on radiographic imaging. Results: The median follow-up duration was 52.3 months (range 7.7 to 179.0 months). The 1-year and 2-year in-field LC rates were 66.0% and 55.0%, respectively. Comparisons of percent change of in-field tumor response showed similar distribution of responses among chemoresistant and chemosensitive tumors. On multivariate analysis of predictive factors for in-field LC analyzed by sites treated, $BED{\geq}50Gy$ (hazard ratio, 0.4; confidence interval, 0.2-0.9; p = 0.025) showed better outcomes. Conclusion: Regardless of resistance to platinum-based chemotherapy, RT can be a feasible treatment modality for patients with persistent of recurrent EOC. The specific role of RT using updated approaches needs to be reassessed.