http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
李志泰 경북대학교 공과대학 1984 工大硏究誌 Vol.13 No.-
A series expansion method for the optimal regulation of nonlinear chemical processes is derived by apply???? perturbation technique to the Bellman's recurrence equation. The approximate solution by this method is accurate can be easily calculated and implemented, which is illustrated by simulating two examples for well-known chemical processes.
작은 이득의 적분오차 궤환시스템에 관한 Riccati식을 풀기위한 섭동법
李志泰 경북대학교 공과대학 1985 工大硏究誌 Vol.14 No.-
출력측의 offset를 없애기 위하여 적분오차 궤환시스템이 많이 이용되고 있다. 이런 궤환시스템을 설계할 때 나타나는 Riccati식을 효율적이면서 수치적으로 안전하게 풀 수 있는 방법을 고안하였다. 섭동법의 기술을 이용하였다. 간단한 예제를 통하여 본 방법의 유용성을 보였다.
Nonlinear pH Control Using a Three Parameter Model
Lee, Jie-Tae,Park, Ho-Cheol Institute of Control 2000 Transaction on control, automation and systems eng Vol.2 No.2
A two parameter model of a single fictitious weak acid with unknown dissociation constant has been successfully applied to design a neutralization system for many multi-component acid streams. But there are some processes for which above two parameter model is not satisfactory due to poor approxmation of the nonlinearity of pH process. Here, for etter control of wide class of multi-component acid streams, a three parameter model of a strong acid and a weak acid with unknown dissociation constant is proposed. The model approximates effectively three types of largest gain variation nonlinearities. Based on this model a nonlinear pH control system is designed. Parameters can eeasily estimated since their combinations appear linearly in the model equations and nonlinear adaptive control system may also be constructed just as with the two parameter model.
Lee, Jie Tae 한국화학공학회 2000 Korean Journal of Chemical Engineering Vol.17 No.5
Nonminimum-phase parts are better removed in the feedback loop like the time delay term. For this, Wright and Kravaris [1992] proposed the concept of optimal minimum-phase output to control nonlinear nonminimum-phase processes. However, their optimal minimum-phase output has no analytic solutions for processes with more than three state variables. Here, methods for analytic minimum-phase outputs approximating the optimal ones are proposed, having no limitations in the number of state variables. The proposed methods provide analytic solutions for processes with three state variables and simple numerical solutions for those with more state variables.
Lee, Jie-Eun,Kim, Kyoung Min,Kim, Lee-Kyung,Kim, Kyong Young,Oh, Tae Jung,Moon, Jae Hoon,Choi, Sung Hee,Lim, Soo,Kim, Sang Wan,Shin, Chan Soo,Jang, Hak Chul Elsevier 2017 Bone Vol.105 No.-
<P><B>Abstract</B></P> <P>Trabecular bone score (TBS) is a parameter of bone quality that has been shown to be related to vertebral fractures. This study aimed to analyze the difference in discriminatory power of TBS for vertebral fractures according to the bone mineral density (BMD) T-score. Areal BMD at the lumbar spine (LS, L1–L4), femur neck (FN) and total hip were assessed using dual x-ray absorptiometry (Discovery W, Hologic, Bedford, MA) in 929 women aged 50years or older. TBS was analyzed using iNsight software (Med-Imaps, Pessac, France). Vertebral fractures were identified on lateral X-ray films of the thoracic and lumbar spine using a semi-quantitative method. The study subjects consisted of 158 subjects (17.0%) with normal BMD, 461 (49.6%) with osteopenia and 310 (33.4%) with osteoporosis. The incident vertebral fractures were observed in 92 (9.9%) subjects, including 59 fractures in osteoporosis, 29 fractures in osteopenia, and only 4 fractures in normal BMD. We stratified study subjects into two groups according to their BMD T-scores, osteoporosis or osteopenia/normal BMD. The logistic regression model showed that LS BMD values per each 1 standard deviation (SD) decrease were significantly associated with increased risk of vertebral fracture in both osteoporosis and osteopenia/normal BMD group with stronger association in osteoporosis group. However, a TBS value that was lower by 1SD was significantly associated with vertebral fracture risk only in the osteopenia/normal BMD group. The TBS use in addition to FN BMD and age also showed significantly better discriminatory power for vertebral fracture only in the osteopenia/normal BMD group, but not osteoporosis group. In conclusion, TBS is significantly associated with vertebral fractures in subjects with osteopenia/normal BMD levels. Additional assessment of bone microarchitecture using TBS is better able to identify women at risk of fracture, in particular, those with relatively higher BMD.</P> <P><B>Highlights</B></P> <P> <UL> <LI> TBS and BMD showed a significant positive correlation and the association becomes stronger as BMD increases. </LI> <LI> TBS could identify women at risk of fracture, in particular, those having relatively higher BMD-osteopenia or normal BMD. </LI> <LI> TBS did not show a significant association with risk of vertebral fractures in subjects having osteoporotic BMD levels. </LI> </UL> </P>