Analytical design of an industrial two-term controller for optimal regulatory control of open-loop unstable processes under operational constraints

Tchamna, Rodrigue,Lee, Moonyong Elsevier 2018 ISA transactions Vol.72 No.-

<P><B>Abstract</B></P> <P>This paper proposes a novel optimization-based approach for the design of an industrial two-term proportional-integral (PI) controller for the optimal regulatory control of unstable processes subjected to three common operational constraints related to the process variable, manipulated variable and its rate of change. To derive analytical design relations, the constrained optimal control problem in the time domain was transformed into an unconstrained optimization problem in a new parameter space via an effective parameterization. The resulting optimal PI controller has been verified to yield optimal performance and stability of an open-loop unstable first-order process under operational constraints. The proposed analytical design method explicitly takes into account the operational constraints in the controller design stage and also provides useful insights into the optimal controller design. Practical procedures for designing optimal PI parameters and a feasible constraint set exclusive of complex optimization steps are also proposed. The proposed controller was compared with several other PI controllers to illustrate its performance. The robustness of the proposed controller against plant-model mismatch has also been investigated.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Optimal regulatory control of open-loop unstable process under operational constraints. </LI> <LI> An optimization based approach to find a global optimal solution of control system. </LI> <LI> The proposed method can handle operational constraints explicitly in controller design. </LI> <LI> The analytical design offers many useful insights to process control practitioners. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Optimization approach for the analytical design of an industrial PI controller for the optimal regulatory control of first order processes under operational constraints

Tchamna, Rodrigue,Lee, Moonyong Elsevier 2017 Journal of the Taiwan Institute of Chemical Engine Vol.80 No.-

<P><B>Abstract</B></P> <P>In this paper, an optimization-based approach for the closed-form design of an industrial proportional-integral (PI) controller was proposed for the optimal regulatory control of first order process under three typical operational constraints. An ingenious parameterization with Lagrangian multiplier method was used to convert the constrained optimal control problem in the time domain to an unconstrained optimization problem to derive an analytical solution for the optimal regulatory control. Three typical operational constraints could be taken into account in the controller design stage, explicitly. The proposed analytical design method required no complicated optimization steps and guaranteed global optimal closed-loop performance and stability. The proposed analytical approach also provides useful insights into the optimal controller design and analysis. A practical and facile procedure for designing optimal PI parameters and a feasible constraint set was also proposed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Analytical design of a PI controller for chemical processes is proposed. </LI> <LI> The controller handles the control performance and the operational constraints. </LI> <LI> The controller shows the connection between the plant and controller parameters. </LI> <LI> A procedure is provided, helping to know if a given constraint set is feasible. </LI> <LI> If the constraint set cannot be satisfied, the procedure suggests how to tune it. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The proposed PI controller design guarantees global optimal regulatory closed-loop performance and stability requiring no complicated optimization steps </P> <P>[DISPLAY OMISSION]</P>

유전자 알고리즘과 파레토 최적을 이용한 공동주택 환기시스템의 최적설계

김영진(Kim Young-Jin),박철수(Park Cheol-Soo) 한국건축친환경설비학회 2007 한국건축친환경설비학회 학술발표대회 논문집 Vol.- No.-

This paper addresses optimal design of ventilation system in a apartment floor plan in Korea. In the paper, the optimal design means optimal sizing of such system and optimal location of diffusers/registers. Performance criteria for decision-making includes initial and maintenance costs, indoor air quality, energy use and comfort. The multi-criteria optimal design problem introduces multi-objective optimization with Pareto optimality. In the study, the genetic algorithm was chosen for solving the constrained discrete optimization problem. The CONTAMW 2.4 developed by NIST(National Institute of Science and Technology) was used to simulate ventilation phenomena. The paper shows an example of an optimal design problem for a chosen apartment plan.

스템핑 공정 최적화 시스템의 개발 : 최적블랭크 설계와 최적배치의 일체화 Integration of Optimal Blank Design and Optimal Nesting

박종규,심현보 嶺南大學校 工業技術硏究所 2003 工業技術硏究所論文集 Vol.31 No.1

In recent years, design of an optimal blank shape is very important for sheet metal forming process in the automobile industry because the raw material cost rate is significant part in the automobile industry. With the design of an optimal blank shape, the engineer can protect a blank from an excessive holding force to improve the quality and reduce the ratio of material scrap. Therefore design of an optimal blank shape is inevitable in sheet metal forming process. However, if it causes a complicated shape of blank, it may be difficult to do the blank layout optimally. In this study, we developed software of optimal blank layout connected with the software of optimal blank shape design which was created in the past by the present authors. And by using these softwares, we would like to present the method in order to get optimal utilization ratio easily and precisely within short time for the sequence of works from design to blank layout.

유전자 알고리즘, 파레토 최적, 환기 시뮬레이션을 통합한 환기 시스템 최적설계

김영진(Kim Young-Jin),박철수(Park Cheol-Soo) 대한건축학회 2008 대한건축학회논문집 Vol.24 No.1

This paper addresses optimal design of ventilation system in an apartment floor plan in Korea. In the paper, the optimal design means optimal sizing and location of supply diffusers/exhaust registers. Performance criteria of decision-making for optimal design includes initial and operation costs, indoor air quality, energy use and comfort. The multi-criteria optimal design problem introduced multi-objective optimization with Pareto optimality. In the study, the Genetic Algorithm (GA) was chosen for solving a constrained discontinuous optimization problem. The CONTAMW 2.4 developed by NIST(National Institute of Science and Technology) was used to simulate ventilation phenomena. This multi-criteria optimization problem was then solved using integration of GA, Pareto optimality and CONTAMW simulation runs. The paper shows an example of an optimal design problem for a chosen apartment plan.

말라리아 감염의 신속 진단을 위한 Parasite Lactate Dehydrogenase-based Immunochromatographic Antigen Assay (DiaMed OptiMAL^�)의 유용성

김자영,임지향,김명신,이승옥,김용구,한경자,강창석 대한임상병리학회 2001 대한임상병리학회지 Vol.21 No.4

배경: 말초혈액도말법은 현재까지 말라리아 감염의 진단에 있어 표준검사법으로 이용되고 있지만 정확한 판독에는 많은 시간과 노력이 필요하다. 최근 말라리아 원충에 특이적으로 존재하는 대사효소인 parasite lactate dehydrogenase (pLDH)에 대한 단클론항체를 이용하여 빠른 시간 내에 말라리아 감염을 진단할 수 있는 면역크로마토그라피법(DiaMed OptiMAL test )이 국내에 소개되었다. 따라서 이 검사법을 말초혈액도말법과 비교하여 말라리아의 신속 진단에 있어 그 유용성을 평가해 보고자 하였다.<br> 재료 및 방법: 임상적으로 말라리아가 의심되어 말초 혈액도 말검사가 의뢰된 44명 환자의 총 58 검체(진단 당시 44검체, 치료후 추적관찰 14검체)를 대상으로 본 연구를 시행하였다. 환자의 EDTA 전혈 한 방울을 pLDH에 특이한 단클론항체가 도포된 dipstick과 반응시킨 후 발색된 band의 유무와 위치로 결과를 판정하였으며 모든 결과는 말초혈액도말법의 결과와 비교하였다.<br> 결과: OptiMAL 검사는 100%인 민감도와 특이도를 나타내었으며 말초혈액도말법과 정확히 일치하였다. 원충 수가 증가할수록 band의 염색강도는 증가하였다. 치료 후 추적검사시 치료에 따라 band 염색강도가 약해졌으며 말초혈액도말법에서보다 먼저 음성소견을 나타내었다.<br> 결론: OptiMAL 검사법은 말라리아 진단에 있어 간단하고 신속하며 정확한 검사법으로, 말라리아의 초기 진단뿐만 아니라 치료 효과 판정 및 추적검사에도 유용한 것으로 생각되었다. Background: Microscopic examination of peripheral blood smears has been a standard diagnostic test for malarial infection for a long time, but it is labor-intensive and time-consuming. Recently, a rapid diagnostic test for malarial infection containing a dipstick bearing monoclonal antibodies against the intracellular metabolic enzyme, parasite lactate dehydrogenase (pLDH), was introduced (DiaMed OptiMAL ). We evaluated the usefulness of the OptiMAL test in malaria diagnosis by comparing with a microscopic examination of peripheral blood smears.<br> Methods: Fifty-eight (initial 44 and follow-up 14) whole blood samples were obtained from 44 patients who were suspected of having malarial infection. After 1 drop of whole blood reacted with the dipstick, band numbers and positions on the dipsticks determined the results. All results were compared to those of microscopic examination findings.<br> Results: The OptiMAL test revealed 100% sensitivity and specificity by comparing with the microscopic examination. The intensity of stained bands showed positively correlated with the severity of parasitemia. The OptiMAL test revealed a more rapid negative conversion than the microscopic examination after treatment.<br> Conclusion: The OptiMAL test is a simple, rapid and accurate test for diagnosis of malarial infection; moreover, it is good tool for monitoring after treatment.

공교육비의 민간 부담과 출산율 선택

김봉주 ( Bong Ju Kim ) 한국경제학회 2015 經濟學硏究 Vol.63 No.4

계층 간 소득격차에 따라 정부가 공교육비를 조세나 민간 부담을 통해 어떻게 조달하는 것이 최적인지를 살펴본 후 다음의 결론을 얻었다. 첫째, 특정시점의 최적교육체제는 계층 간 소득격차가 큰 경우 무상교육이고, 소득 격차가 작은 경우 민간의 교육비 분담이다. 둘째, 소득격차가 매우 클 때, 균제상태에서 무상 공교육을 제공하는 것이 최적이고 안정적이며 유일한 균제상태를 갖는다. 셋째, 소득격차가 클 때, 균제상태를 갖지 않고 인구 비율은 순환할 수 있다. 넷째, 소득격차가 적을 때, 균제상태에서 민간이 교육비를 분담하는 것이 최적이고, 복수의 균제상태를 가지면서 안정적이지 않은 균제상태도 있다. 마지막으로 소득격차가 매우작을 때, 민간의 교육비 분담이 최적이며 안정적이고 유일한 균제상태를 갖는다. 이러한 결과는 무상교육에서 가계가 교육비를 직접 부담하지 않아 초래된 출산율 선택의 왜곡에서 비롯된다. 따라서 소득 불평등이 높아 형평성 제고가 우선시되지 않는 한 이러한 왜곡의 비용이 크기 때문에 최적 교육체제는 민간의 교육비 분담이다. This paper examines funding policies for education in a model with skilled and unskilled workers. We investigate how changes in the income gap between them affect optimal financing. The results are as follows: First, for a very large income gap, pure public financing is optimal in a unique steady-state. Second, for a large income gap, we find out a case in which no steady-state exists and partial private financing is optimal. Third, for a small income gap, partial private financing is optimal in multiple steady-states. Finally, for a very small income gap, partial private financing is optimal in a unique steady-state. The reason for these results is that pure public financing improves equity but causes inefficient fertility choice. Thus, from this trade-off between equity and efficiency, pure public financing is optimal when inequality is very high.

Optimal Design of a Novel Permanent Magnetic Actuator using Evolutionary Strategy Algorithm and Kriging Meta-model

Seung-Ki Hong,Jong-Suk Ro,Hyun-Kyo Jung 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.2

The novel permanent magnetic actuator (PMA) and its optimal design method were proposed in this paper. The proposed PMA is referred to as the separated permanent magnetic actuator (SPMA) and significantly superior in terms of its cost and performance level over a conventional PMA. The proposed optimal design method uses the evolutionary strategy algorithm (ESA), the kriging meta-model (KMM), and the multi-step optimization. The KMM can compensate the slow convergence of the ESA. The proposed multi-step optimization process, which separates the independent variables, can decrease time and increase the reliability for the optimal design result. Briefly, the optimization time and the poor reliability of the optimum are mitigated by the proposed optimization method.

Precise-Optimal Frame Length Based Collision Reduction Schemes for Frame Slotted Aloha RFID Systems

( Sunil Dhakal ),( Seokjoo Shin ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.1

An RFID systems employ efficient Anti-Collision Algorithms (ACAs) to enhance the performance in various applications. The EPC-Global G2 RFID system utilizes Frame Slotted Aloha (FSA) as its ACA. One of the common approaches used to maximize the system performance (tag identification efficiency) of FSA-based RFID systems involves finding the optimal value of the frame length relative to the contending population size of the RFID tags. Several analytical models for finding the optimal frame length have been developed; however, they are not perfectly optimized because they lack precise characterization for the timing details of the underlying ACA. In this paper, we investigate this promising direction by precisely characterizing the timing details of the EPC-Global G2 protocol and use it to derive a precise-optimal frame length model. The main objective of the model is to determine the optimal frame length value for the estimated number of tags that maximizes the performance of an RFID system. However, because precise estimation of the contending tags is difficult, we utilize a parametric-heuristic approach to maximize the system performance and propose two simple schemes based on the obtained optimal frame length―namely, Improved Dynamic-Frame Slotted Aloha (ID-FSA) and Exponential Random Partitioning-Frame Slotted Aloha (ERP-FSA). The ID-FSA scheme is based on the tag set estimation and frame size update mechanisms, whereas the ERP-FSA scheme adjusts the contending tag population in such a way that the applied frame size becomes optimal. The results of simulations conducted indicate that the ID-FSA scheme performs better than several well-known schemes in various conditions, while the ERP-FSA scheme performs well when the frame size is small.

Optimal Commodity Taxation in the Presence of Involuntary Unemployment : Importance of Progressive Income Taxation and Unemployment Insurance

Chul-In Lee 한국재정학회(구 한국재정·공공경제학회) 2004 한국재정학회 학술대회 논문집 Vol.2004 No.2

This paper addresses the optimal commodity taxation when involuntary unemployment arises from redistributive fiscal policies, e.g., a progressive income tax system and social insurance/welfare programs. This setting deals with a new dimension of distortions: the “between-states” (employment state vs. unemployment state) consumption choice distortion along with the usual “within-state” distortion conditional on a given state. We derive the optimal commodity taxation rule in the presence of the redistributive fiscal policies in a simplified ‘general-equilibrium’ efficiency wage model with effort and commodity choices. In contrast to the conventional results by Ramsey (1927) and Atkinson and Stiglitz (1976) that consider the within-state distortion only, we show that under the weakly separable utility and the constant marginal cost technology, uniform commodity taxation is optimal only when the government can choose all commodities’ tax rates. If at least one good’s tax rate is fixed at a certain level (e.g., due to redistributive purpose or to foreign competition), non-uniform commodity taxation is generally optimal. The intuition is that a deviation from uniform commodity taxation can alleviate the betweenstates distortion, moral hazard arising from a progressive income tax system and social insurance/welfare programs. This gain, combined with resulting greater effort and higher utilization of labor (i.e., lower unemployment), can outweigh the within-state consumption choice distortions from non-uniform taxation. Useful policy implications are also discussed.