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Semiconductor manufacturing technology keeps toward scaling down to a few nanometers. To protect the process yield and achieve the success of chip manufacturing, the center-to-edge uniformity of the wafer's temperature has become a crucial parameter. The thermal characteristics of the wafer are dominantly affected by the electrostatic chuck, which is generally used to support the wafer in the manufacturing process. In particular, the backside gas, which passes through the interface between the wafer and electrostatic chuck, is important for cooling the wafer below a critical temperature. The heat transfer via a backside gas can be explained by the layer-bulk model, and its pressure is a key factor to determine the cooling effectiveness. In this paper, a one-dimensional thermal circuit model is established for a system including the wafer, electrostatic chuck, and backside gas to calculate the convective heat transfer coefficient caused by the backside gas. The numerical results showed that the uniformity of the wafer's temperature became worse as the backside gas pressure increased in a low-pressure range but significantly improved above a critical value of the gas pressure. Based on our findings, we concluded that the backside gas pressure should be optimized to improve the uniformity of the wafer temperature.

Optoelectronic devices consist of heterointerfaces formed between dissimilar semiconducting materials. The relative energy-level alignment between contacting semiconductors determinately affects the heterointerface charge injection and extraction dynamics. For perovskite solar cells (PSCs), the heterointerface between the top perovskite surface and a charge-transporting material is often treated for defect passivation(1-4) to improve the PSC stability and performance. However, such surface treatments can also affect the heterointerface energetics(1). Here we show that surface treatments may induce a negative work function shift (that is, more n-type), which activates halide migration to aggravate PSC instability. Therefore, despite the beneficial effects of surface passivation, this detrimental side effect limits the maximum stability improvement attainable for PSCs treated in this way. This trade-off between the beneficial and detrimental effects should guide further work on improving PSC stability via surface treatments.

This study proposes a switching proportional-derivative (PD) controller for a press platform for inspecting the surfaces of a wind turbine blade. We use the Hunt-Crossley model to represent the probe shape or the nonlinearity of the inspection platform. This model consists of a nonlinear spring and a damper; therefore, it is more accurate than linear spring-damper models. We prove the global asymptotic stability of a PD force feedback controller and a PD position feedback (force) controller. However, both the controllers suffer from implementation-related problems. Specifically, the PD force feedback controller makes the impact force large, and the PD position feedback controller cannot easily measure small position changes when the platform contacts the surface. These problems of each controller are solved by switching the two controllers. The PD force feedback control and PD position feedback control are used when the platform is in the contact and noncontact states, respectively. We prove that the proposed switching PD force/position feedback controller is globally asymptotically stable. Further, simulations show satisfactory performance resulting from stable switching between the two control schemes.

In the concept of smart cities, technology is becoming centric over living and non-living beings in the cities. Radically saying, human beings are becoming human resources, and non-humans are being excluded from smart city plans but only focus on those qualified smart city people. The minorities, non-human living things, and even mother nature are being sacrificed under the name of technological advance since it is assumed that smart cities possibly control and care for them. This paper is to ask what and how smart cities should be in the next generation of city development if all living and non-living beings can be treated the same as the city members. To do so, we critically review the concepts of smart cities and human smart cities using three well-known smart cities’ planning phases including Barcelona, Dubai, and Singapore. Criticizing their human dimensions of smart cities, we legitimate three posthumanist dimensions: non-dualism, more-than-humans, and ecological community to ensure that the next generation of smart cities becomes inclusive of all humans, non-humans, and more-than-humans. From the legitimation, we articulate emerging values: inclusion, agency, and smartness which should be considered to embed each posthumanist dimension in smart city planning. Using this new posthumanistic framework, we evaluate three popular smart city evaluation models to prove their anti-humanism and anti-non-humanism aspects in detail and argue that the framework is meaningful and effective to ensure that next smart cities are free from dualistic anthropocentrism at least.

Improving semiconductor equipment and components is an important goal of semiconductor manufacture. Especially during the deposition process, the temperature of the wafer must be precisely controlled to form a uniform thin film. In the conventional plasma-enhanced chemical vapor deposition (PECVD) chuck, heating rate, and temperature uniformity are limited by the spiral pattern and volume of the heating element. To overcome the structural limitation of the heating element of conventional chuck, we tried to develop the planar heating chuck (PHC), a 6-inch PECVD chuck with a planar heating element based on NiCr thin film that would be a good candidate for rapidly and uniformly heating. The time for the temperature elevation from room temperature to 330 °C was 398 s. In a performance evaluation, the fabricated PHC successfully completed a SiO2 PECVD process.

Purpose: Metabolic syndrome (MetS) is a strong risk factor for type 2 diabetes and atherosclerotic cardiovascular diseases, and its pathological process starts from childhood and adolescence. Childhood and adolescence is an important developmental stage where gender-specific body image, self-identity, and health habits are formed. This study examined gender-specific factors associated with MetS among Korean children and adolescents. Method: Using data from the Korea National Health and Nutrition Examination Survey 5th and 6th waves (2010-2015), a total of 4,149 respondents (representing 4.6 million children and adolescents aged 10 to 18) were evaluated. MetS was defined based on the guidelines of the modified NCEP ATP III. Data were analyzed with descriptive statistics, independent t-test, χ2 -test and univariate logistic regression analysis (p < .05). Results: The prevalence rate of MetS in Korean children and adolescents was 4.17% (4.88% in boys and 3.42% in girls). The prevalence of abdominal obesity was significantly higher in girls (8.96% vs. 11.17%), and the prevalence of low HDL-C and elevated BP were significantly higher in boys (14.13% vs. 9.65%; 29.15% vs. 25.65%). For boys, increasing age, BMI, Waist-to-Height ratio (WHtR), one meal per day, weight loss effort, and perceived body shape as “fat” were significantly associated with MetS. For girls, BMI, WHtR, familial medical history of low HDL-C, weight loss effort, and perceived body shape as “average” and “fat” were significantly associated with MetS. Risk factors unique to boys were age and frequency of meal per day, whereas familial medical history of low HDL-C and perceived body shape as “average” were specific to girls. Conclusion: We found gender differences in the prevalence of MetS and its associated risk factors in Korean children and adolescents. Gender-difference should be considered in an effort to address MetS and risk factors in this population. Disclosure J. Choi: None. T. Yoon: None. M. Yu: None. D. Kang: None. S.E. Choi: None. Funding National Research Foundation of Korea (2017R1C1B5076837)

We investigated whether changes in adiponectin levels over time predict incident metabolic syndrome (MetS) in a population-based prospective study. In total, 1110 subjects were categorized into four groups according to their sex-specific median baseline adiponectin levels and the change in adiponectin levels at follow-up: low baseline adiponectin and decreased adiponectin during follow-up (LB&amp, DF), low baseline adiponectin and increased adiponectin during follow-up (LB&amp, IF), high baseline adiponectin and decreased adiponectin during follow-up (HB&amp, DF), and high baseline adiponectin and increased adiponectin during follow-up (HB&amp, IF). During the median 2.4-year follow-up period, 180 (16.2%) subjects developed MetS. Compared to the LB&amp, DF group, the fully adjusted hazard ratio (95% confidence interval) for incident MS was the lowest in the HB&amp, IF group (0.33, (0.17&ndash, 0.63)), followed by the HB&amp, DF group (0.58, (0.40&ndash, 0.84)) and LB&amp, IF group (0.63, (0.41&ndash, 0.93)). This phenomenon was more prominent in men than in women. Among the individual MetS components, increased adiponectin levels during follow-up were significantly associated with lower risks of incident low high density lipoprotein (HDL) cholesterol and incident high blood pressure. This finding suggests that a change in adiponectin level, as well as the baseline adiponectin level, might have a clinical role in the development of MetS among men.

Objective: The purpose of this study is to investigate the injury patterns of noncatastrophic accidents by individual age groups. Methods: Data were collected from the Korean In-Depth Accident Study database based on actual accident investigation. The noncatastrophic criteria were classified according to U.S. experts from the Centers for Disease Control and Prevention’s recommendations for field triage guidelines of high-risk automobile crash criteria by vehicle intrusions more than 12 in. on occupant sites (including the roof) and more than 18 in. on any site. The Abbreviated Injury Scale (AIS) was used to determine injury patterns for each body region. Severely injured patients were classified as Maximum Abbreviated Injury Scale (MAIS) 3 or higher. Results: In this study, the most significant injury regions were the head and neck, extremities, and thorax. In addition, the incidence of severe injury among elderly patients was nearly 1.6 times higher than that of non-elderly patients. According to age group, injured body regions among the elderly were the thorax, head and neck, and extremities, in that order. For the non-elderly groups, these were head and neck, extremities, and thorax. Severe injury rates were slightly different for the elderly group (head and neck, abdomen) and non-elderly group (thorax, head and neck). Conclusions: In both age groups, the rate of severe injury is proportional to an increase in crush extent zone. Front airbag deployment may have a relatively significant relationship to severe injuries.

A third-order nonlinear model for organic light emitting diodes (OLEDs) is presented. The model can consistently describe dynamic and static characteristics of OLEDs. The model can also be used to estimate the physical characteristics of specific layers of an OLED. The parameters of the proposed model are estimated using a trust-region algorithm and a particle swarm optimization algorithm. Several of the resulting parameters relate to the electrical and light emission characteristics of OLEDs. Using only one set of experiments on an OLED device, a nonlinear model including all parameters, can be obtained; this method is highly advantageous for the fast quality control of OLEDs.

This article presents a high-efficiency power amplifier using quasi-MMIC technology. The efficiency enhancement is achieved based upon the second or third harmonic control provided by input and output matching networks. The gate-source voltage waveform control with Class-F operation achieves significant efficiency improvements. The quasi-MMIC technology using silicon-integrated passive devices (Si-IPDs) can drive the solution to provide compact size at 2.4 GHz. The output matching network for Class-F operation is described, using lumped elements to reduce circuit size. The dimensions of the fabricated power amplifier are 3.6 mm × 7.6 mm, with a thickness of 0.15 mm. The measured results show that the power amplifier has a small signal gain of about 10 dB and a Psat of 41.8 dBm with a maximum drain efficiency of 70.8% at 2.4 GHz. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2178–2182, 2016

PURPOSE This study was performed to identify the prevalence of menstrual disorders in Korean women based on body mass index (BMI) and lifestyle factors, by utilizing the Korean National Health Insurance Database. METHODS A retrospective observational study design was used for the secondary data analysis. Data of women aged 15 to 49 years who were diagnosed with menstrual disorders were extracted from The National Health Insurance Service-National Health Screening Cohort in Korea from 2009 to 2016. The age-standardized prevalence rate of menstrual disorders was calculated using SAS version 9.4, and a Chi-square test and Cochran-Armitage test were performed. RESULTS In total, 2,219,445 cases were extracted from the database. The prevalence of menstrual disorders significantly increased from 8.6% to 11.6% (Z=135.16, p for trend

Human immunodeficiency virus (HIV) causes acquired immune deficiency syndrome (AIDS). The process of infection and mutation by HIV can be described by fifth-order ordinary differential equations. These equations can be reduced to third-order differential equations through the singular perturbation theory. The objective of this paper is to present a parameter estimation algorithm for this third-order HIV model, using two (out of three) state variables. We first show that the parameters of the HIV model are identifiable with these measurements. The structure of the proposed estimator parallels that of the full state feedback estimator with the unavailable state replaced with an estimated variable. We then prove that the resulting adaptive observer equipped with the so-called σ-modification can be tuned to be ultimately bounded under some conditions in terms of the concentration of uninfected CD4+ T cells. Furthermore, it is seen through computer simulations that an iterative application of the proposed algorithm is effective; the estimated parameters approach their true values, and the stability analysis of the ensuing HIV model leads to the results that are consistent with those obtained previously.

On the basis of the non-linear third-order generator model, this article proposes a dual control scheme for a single synchronous machine equipped with an energy storage device to regulate the terminal voltage while enhancing the damping. Based on the input-output feedback linearisation method, the exciter controller is designed such that the terminal voltage robustly converges to its predetermined reference in the presence of a model uncertainty. In addition, the control input of the energy storage device feedbacks only the relative speed. It is shown that this controller can effectively increase the damping of the synchronous machine and that there is a set of initial conditions such that all trajectories started from this set go to the equilibrium point, satisfying input constraints. Moreover, it is also verified that all generator variables are bounded except for the power angle. The simulation results show that the closed-loop performance is satisfactory despite a transmission line fault and a model u...

The HIV (Human Immunodeficiency Virus) causes AIDS (Acquired Immune Deficiency Syndrome). The process of infection and mutation by HIV can be described by a 3rd order state equation. For this HIV model that includes the dynamics of the mutant virus, we present a parameter estimation scheme using two state variables sporadically measured, out of the three, by employing a genetic algorithm. It is assumed that these non-uniformly sampled measurements are subject to random noises. The effectiveness of the proposed parameter estimation is demonstrated by simulations. In addition, the estimated parameters are used to analyze the equilibrium points of the HIV model, and the results are shown to be consistent with those previously obtained.

Feedback circuits are crucial dynamic motifs which occur in many biomolecular regulatory networks. They play a pivotal role in the regulation and control of many important cellular processes such as gene transcription, signal transduction, and metabolism. In this study, we develop a novel computationally efficient method to identify feedback loops embedded in intracellular networks, which uses only time-series experimental data and requires no knowledge of the network structure. In the proposed approach, a non-parametric system identification technique, as well as a spectral factor analysis, is applied to derive a graphical criterion based on non-causal components of the system's impulse response. The appearance of non-causal components in the impulse response sequences arising from stochastic output perturbations is shown to imply the presence of underlying feedback connections within a linear network. In order to extend the approach to nonlinear networks, we linearize the intracellular networks about an equilibrium point, and then choose the magnitude of the output perturbations sufficiently small so that the resulting time-series responses remain close to the chosen equilibrium point. In this way, the impulse response sequences of the linearized system can be used to determine the presence or absence of feedback loops in the corresponding nonlinear network. The proposed method utilizes the time profile data from intracellular perturbation experiments and only requires the perturbability of output nodes. Most importantly, the method does not require any a priori knowledge of the system structure. For these reasons, the proposed approach is very well suited to identifying feedback loops in large-scale biomolecular networks. The effectiveness of the proposed method is illustrated via two examples: a synthetic network model with a negative feedback loop and a nonlinear caspase function model of apoptosis with a positive feedback loop.

This paper proposes a dynamic compensation scheme for input-constrained feedback linearizable nonlinear systems to cope with the windup phenomenon. Given a dynamic feedback linearizing controller designed without considering its input constraint, an additional dynamic compensator is proposed to account for the constraint. This dynamic anti-windup is based on the minimization of a reasonable performance index. The proposed strategy is a nonlinear extended version of [Park, J.-K., & Choi, C.-H. (1995). Dynamic compensation method for multivariable control systems with saturating actuators. IEEE Transactions on Automatic Control, 40(9), 1635-1640] with simplified derivation of an optimization solution under relaxed assumptions. The parameter matrices and structure of the solution are explicitly decided by mathematical optimization for infinite horizon without tuning of design parameters unlike previous schemes. During input saturation, the role of the anti-windup scheme with the proposed dynamic feedback compensator is to maintain the controller states to be exactly the same as those without input saturation. The local asymptotic stability and the total stability of the resulting systems are proved. The usefulness of the proposed design method is illustrated by comparative simulations for a constrained control system.

An adaptive output feedback model predictive control (MPC) for an uncertain input-constrained neutrally stable linear plant using control-relevant switching is presented. By employing an input-to-state stabilising MPC as the multi-controller, switching adaptive output feedback MPC is proposed for the system. Unlike previous methods for handling uncertainties on the basis of minmax MPC laws or techniques for linear parameter varying systems, the proposed MPC scheme employs model switching to deal with modelling uncertainties through adaptation; a best model is selected for the MPC law from time to time. The proposed scheme using finite prediction horizon guarantees global stability. Simulation results are given to show the effectiveness of the scheme.

Feedback loops play pivotal roles in the regulation and control of many important cellular processes such as gene transcription, signal transduction, and metabolism. Hence, identification of feedback loops embedded in biomolecular regulatory networks is crucial to understanding the regulatory mechanisms underlying various cellular processes. In this paper, we introduce an identification method called the intermittent step perturbation method (ISPM) that can efficiently identify and locate feedback connectivities among reacting biomolecules. In particular, a sort of stochastic function called an intermittent step perturbation is applied to excite a given network. Then, we employ a statistical algorithm to analyze the resulting time-series data, thereby discerning any causal connection with a circular causal property. This circular causal property implies the existence of a feedback loop in the regulatory network. Finally, the proposed ISPM is demonstrated through an insulin signal transduction pathway model.

This paper presents a discrete-time supervisory control scheme for an input-constrained neutrally stable linear plant in the presence of modelling uncertainties. The small gain control is employed as the multi-controller, and is shown to stabilize the plant in the sense of integral-input-to-state stability. As the switching logic, a state-dependent dwell-time switching is employed. The proposed supervisory control guarantees that all signals in the closed loop are bounded and the state of the uncertain plant converges to the origin.

Many nonlinear controllers for the power system are based on nonlinear models involving the power angle as an element of the state, and therefore the reference value for the power angle is needed. As this reference value is not generally available, it is difficult to apply such nonlinear control methods in practice. To deal with this problem, we present an input-output feedback linearizing control scheme by selecting the output as a combination of the squared voltage and the relative frequency. It is shown that the internal dynamics are locally stable with controllable damping, and that the frequency remains bounded for all time. Simulations illustrate the effectiveness of the proposed method.

MPC or model predictive control is representative of control methods which are able to handle inequality constraints. Closed-loop stability can therefore be ensured only locally in the presence of constraints of this type. However, if the system is neutrally stable, and if the constraints are imposed only on the input, global asymptotic stability can be obtained; until recently, use of infinite horizons was thought to be inevitable in this case. A globally stabilizing finite-horizon MPC has lately been suggested for neutrally stable continuous-time systems using a non-quadratic terminal cost which consists of cubic as well as quadratic functions of the state. The idea originates from the so-called small gain control, where the global stability is proven using a non-quadratic Lyapunov function. The newly developed finite-horizon MPC employs the same form of Lyapunov function as the terminal cost, thereby leading to global asymptotic stability. A discrete-time version of this finite-horizon MPC is presented here. Furthermore, it is proved that the closed-loop system resulting from the proposed MPC is ISS (Input-to-State Stable), provided that the external disturbance is sufficiently small. The proposed MPC algorithm is also coded using an SQP (Sequential Quadratic Programming) algorithm, and simulation results are given to show the effectiveness of the method.

This paper presents a new supervisory control scheme, which is based on a control-relevant switching logic. Unlike most of the existing switching methods considering only estimator performance, the proposed scheme takes both estimator and controller performance into account. As an index to the controller performance, an iISS (integral-Input-to-State Stability) Lyapunov function is employed; it is ensured that the Lyapunov function satisfies a certain inequality. This Lyapunov-based switching is then coupled to the state-dependent dwell-time switching developed recently, and the state of the uncertain plant is shown to converge asymptotically .

This paper presents a discrete-time supervisory control of an input constrained neutrally stable linear plant in the presence of modelling uncertainties. The small gain control is employed as the multi-controller, and is shown to integral-input-to-state stabilizes the plant. As the switching logic, a state dependent dwell-time switching is employed. The proposed supervisory control guarantees that all signals in the system are bounded and the state of the uncertain plant converges to the origin.

This paper presents an indirect adaptive control scheme for a pH process, which is difficult to control due to its nonlinear dynamics with uncertainties. A nonlinear controller is designed using a backstepping technique which can deal with a large class of nonlinear systems with parametric uncertainty. The nonlinear controller is combined with a parameter estimator to estimate the concentrations of the reaction invariants in the wastewater stream, and the stability of the proposed adaptive scheme is proved. Simulations show that uniform closed-loop performance is obtained despite the nonlinearities and parametric uncertainties.

This paper proposes a dynamic compensation scheme for input-constrained linear systems to cope with the windup phenomenon. Given a linear controller for such a linear system designed without considering its input constraints, an additional dynamic compensator is proposed to account for the constraints. This dynamic anti-windup scheme is based on ℋ ∞ optimization, and some stability properties of the resulting closed-loop system are given.