High-order volterra model predictive control and its application to a nonlinear polymerisation process

Model Predictive Control (MPC) has recently found wide acceptance in the process industry, but the existing design and implementation methods are restricted to linear process models. A chemical process involves, however, severe nonlinearity which cannot be ignored in practice. This paper aims to solve this nonlinear control problem by extending MPC to nonlinear models. It develops an analytical framework for nonlinear model predictive control (NMPC), and also offers a third-order Volterra series based nonparametric nonlinear modelling technique for NMPC design which relieves practising engineers from the need for first deriving a physical-principles based model. An on-line realisation technique for implementing the NMPC is also developed. The NMPC is then applied to a Mitsubishi Chemicals polymerisation reaction process. The results show that this nonlinear MPC technique is feasible and very effective. It considerably outperforms linear and low-order Volterra model based methods. The advantages of the approach developed lie not only in control performance superior to existing NMPC methods, but also in relieving practising engineers from the need for deriving an analytical model and then converting it to a Volterra model through which the model can only be obtained up to the second order

CAutoCSD-evolutionary search and optimisation enabled computer automated control system design

This paper attempts to set a unified scene for various linear time-invariant (LTI) control system design schemes, by transforming the existing concept of 'Computer-Aided Control System Design' (CACSD) to the novel 'Computer-Automated Control System Design' (CAutoCSD). The first step towards this goal is to accommodate, under practical constraints, various design objectives that are desirable in both time and frequency-domains. Such performance-prioritised unification is aimed to relieve practising engineers from having to select a particular control scheme and from sacrificing certain performance goals resulting from pre-committing to the adopted scheme. With the recent progress in evolutionary computing based extra-numeric, multi-criterion search and optimisation techniques, such unification of LTI control schemes becomes feasible, analytically and practically, and the resultant designs can be creative. The techniques developed are applied to, and illustrated by, three design problems. The unified approach automatically provides an integrator for zero-steady state error in velocity control of a DC motor, meets multiple objectives in designing an LTI controller for a non-minimum phase plant and offers a high-performing LTI controller network for a nonlinear chemical process

Validating Variational Bayes Linear Regression Method With Multi-Central Datasets.

PurposeTo validate the prediction accuracy of variational Bayes linear regression (VBLR) with two datasets external to the training dataset.MethodThe training dataset consisted of 7268 eyes of 4278 subjects from the University of Tokyo Hospital. The Japanese Archive of Multicentral Databases in Glaucoma (JAMDIG) dataset consisted of 271 eyes of 177 patients, and the Diagnostic Innovations in Glaucoma Study (DIGS) dataset includes 248 eyes of 173 patients, which were used for validation. Prediction accuracy was compared between the VBLR and ordinary least squared linear regression (OLSLR). First, OLSLR and VBLR were carried out using total deviation (TD) values at each of the 52 test points from the second to fourth visual fields (VFs) (VF2-4) to 2nd to 10th VF (VF2-10) of each patient in JAMDIG and DIGS datasets, and the TD values of the 11th VF test were predicted every time. The predictive accuracy of each method was compared through the root mean squared error (RMSE) statistic.ResultsOLSLR RMSEs with the JAMDIG and DIGS datasets were between 31 and 4.3 dB, and between 19.5 and 3.9 dB. On the other hand, VBLR RMSEs with JAMDIG and DIGS datasets were between 5.0 and 3.7, and between 4.6 and 3.6 dB. There was statistically significant difference between VBLR and OLSLR for both datasets at every series (VF2-4 to VF2-10) (P < 0.01 for all tests). However, there was no statistically significant difference in VBLR RMSEs between JAMDIG and DIGS datasets at any series of VFs (VF2-2 to VF2-10) (P > 0.05).ConclusionsVBLR outperformed OLSLR to predict future VF progression, and the VBLR has a potential to be a helpful tool at clinical settings

Nonparametric nonlinear model predictive control

Model Predictive Control (MPC) has recently found wide acceptance in industrial applications, but its potential has been much impeded by linear models due to the lack of a similarly accepted nonlinear modeling or databased technique. Aimed at solving this problem, the paper addresses three issues: (i) extending second-order Volterra nonlinear MPC (NMPC) to higher-order for improved prediction and control; (ii) formulating NMPC directly with plant data without needing for parametric modeling, which has hindered the progress of NMPC; and (iii) incorporating an error estimator directly in the formulation and hence eliminating the need for a nonlinear state observer. Following analysis of NMPC objectives and existing solutions, nonparametric NMPC is derived in discrete-time using multidimensional convolution between plant data and Volterra kernel measurements. This approach is validated against the benchmark van de Vusse nonlinear process control problem and is applied to an industrial polymerization process by using Volterra kernels of up to the third order. Results show that the nonparametric approach is very efficient and effective and considerably outperforms existing methods, while retaining the original data-based spirit and characteristics of linear MPC

Smallpox and Season: Reanalysis of Historical Data

Seasonal variation in smallpox transmission is one of the most pressing ecological questions and is relevant to bioterrorism preparedness. The present study reanalyzed 7 historical datasets which recorded monthly cases or deaths. In addition to time series analyses of reported data, an estimation and spectral analysis of the effective reproduction number at calendar time t, R(t), were made. Meteorological variables were extracted from a report in India from 1890–1921 and compared with smallpox mortality as well as R(t). Annual cycles of smallpox transmission were clearly shown not only in monthly reports but also in the estimates of R(t). Even short-term epidemic data clearly exhibited an annual peak every January. Both mortality and R(t) revealed significant negative association (P < .01) and correlation (P < .01), respectively, with humidity. These findings suggest that smallpox transmission greatly varies with season and is most likely enhanced by dry weather

카시와기 히로시 인터뷰

1. Since years before, you have mentioned the concept of Digital Bauhaus. Like Bauhaus emerged in early 20th century when drastic social change occurred due to machine production technology, perhaps you saw digital technology will bring drastic change and the new Bauhaus adequate for the 21st century. In what context have you mentioned the Digital Bauhaus, and do you still think it is possible? To what I remember, I mentioned Digital Bauhaus concept in the 1990s. The Bauhaus movement in the 1920s, with mechanical technology deeply embedded in life at the times as the background, pursued realization of new integrated design. Also its aim was collaboration between each technicians, artists, designers and architects to achieve this. The name BAUHAUS is with reference to BAUHUTTE (term for architectural studio where technicians and architects collaborated for building cathedrals and etc in the past). After the 1980s, it was thought that the digital technology embedded in our daily life will change our life style. Therefore, holistic design form (like the case of Bauhaus where experts of different fields have collaborated and generated thoughts) based on digital technology –the Digital Bauhaus- was suggested. Unfortunately the suggestion ended without significant attention. In modern days where digital technology has become everyday life, holistic design through collaboration based on digital technology is still important. 1. 오래전에 디지털 바우하우스라는 개념을 언급하신 것으로 알고 있습니다. 기계 생산 기술로 급격한 사회 변화가 일어난 20세기 초에 바우하우스가 등장했듯이 디지털 테크놀로지가 또 한번 급격한 변화를 일어나는 21세기에 그에 걸맞는 바우하우스의 등장이 가능하리라 생각하신 것이 아닌가 합니다. 어떤 의미로 디지털 바우하우스를 언급하셨는지, 그리고 오늘도 그것이 가능하다 고 생각합니까? "디지털 바우하우스"라는 개념을 말한 것이 1990년대 이었다고 기억하고 있습니다. 1920년대에 전개된 바우하우스의 활동은, 당시 급속하게 일상생활 속으로 침투했던 "기계 기술"을 배경으로, 새로운 통합적 디자인의 실현을 추구했습니다. 또한 그를 위하여 기술 자, 예술가, 디자이너, 건축가가 각각 협동하는 것을 목표로 했습니다. BAUHAUS라고 하 는 명칭은, 과거에 대성당 등의 건축 작업을 할 때 기술자나 건축가가 모여서 일을 하는 건 축 작업장 (BAUHUTTE)을 의식하고 있었습니다. 1980년대 이후, 일상생활에 침투된 디지 털 테크놀로지는 당시 우리 생활의 형태도 바꿀 것이라고 생각했습니다. 그래서 디지털 테 크놀로지를 전제로 한 종합적인 디자인의 형태를, 바우하우스의 경우처럼 여러 영역의 전 문가와 협동해서 생각해 나가자고 제안 한 것이 "디지털 바우하우스"였습니다. 하지만 유 감스럽게도 큰 반향은 없이 끝났습니다. 디지털 테크놀로지가 일상화된 현재, 그것을 전제로 한 총합디자인을 협동하여 생각하는 것은 지금도 중요하다고 생각합니다

Clotting Changes, Including Disseminated Intravascular Coagulation, during Rapid Renal-Homograft Rejection

One of two patients in whom early homograft rejection developed after renal transplantation had many antidonor antibodies before operation. By the measurement of gradients across intracorporeal and extracorporeal homografts in this patient, the new kidneys were shown to sequester host immunoglobulins, platelets, white cells and clotting factors. Moreover, the renal venous blood then contained fibrinolytic activity. This presensitized recipient, as well as a second patient who did not have detectable preformed humoral antibodies, gave evidence from clinical observation and from the various clotting tests of disseminated intravascular coagulation with fibrinolysis and a severe bleeding diathesis. Immunofluorescent and histologic studies revealed a laying down of fibrin in the homograft vessels that continued in some cases to cortical necrosis of the transplanted kidneys or, alternatively, receded at the time fibrinolysis occurred. The variety of rejection seen in these patients has been characterized as an immunologically induced coagulopathy. © 1970, Massachusetts Medical Society. All rights reserved

A Case of Meningococcal Meningitis in Tokyo and A Carrier Rate of Neisseria meningitidis in Those Close to The Patient.

Serogroup B Neisseria meningitidis was isolated from a 3-year-old girl with acute meningitis. The patient was completely recovered from the disease by the successful treatment by ampicillin and cefotaxime. From nasopharyngeal swab culture, N. meningitidis was isolated from her parents and 5 out of 93 pupils and kindergarten staff. The isolates from the parents were serogroup B and those from the pupils of the kindergarten were serogroup A. Since the mother of the patient reported an episode of common cold-like symptoms a few days before the patient\u27s illness, we speculate that the mother was the possible source of infection

An improved physico-chemical model of hybridization on high-density oligonucleotide microarrays

Motivation: High-density DNA microarrays provide useful tools to analyze gene expression comprehensively. However, it is still difficult to obtain accurate expression levels from the observed microarray data because the signal intensity is affected by complicated factors involving probe–target hybridization, such as non-linear behavior of hybridization, non-specific hybridization, and folding of probe and target oligonucleotides. Various methods for microarray data analysis have been proposed to address this problem. In our previous report, we presented a benchmark analysis of probe–target hybridization using artificially synthesized oligonucleotides as targets, in which the effect of non-specific hybridization was negligible. The results showed that the preceding models explained the behavior of probe–target hybridization only within a narrow range of target concentrations. More accurate models are required for quantitative expression analysis