Design Method Research Articles

Single-etched fiber-chip coupler with a metal mirror on a 220-nm silicon-on-insulator platform for perfectly vertical coupling.

Vertical couplers play a pivotal role as essential components supporting interconnections between fibers and photonic integrated circuits (PICs). In this study, we propose and demonstrate a high-performance perfectly vertical coupler based on a three-stage inverse design method, realized through a single full etching process on a 220-nm silicon-on-insulator (SOI) platform with a backside metal mirror. Under surface-normal fiber placement, experimental results indicate a remarkable 3-dB bandwidth of 99 nm with a peak coupling efficiency of -1.44 dB at the wavelength of 1549 nm. This achievement represents the best record to date, to the best of our knowledge, for a perfectly vertical coupler fabricated under similar process conditions.

Design of a Millimeter-Wave Broadband Linearizer Based on an Extended Design Space

In this study, a broadband linearizer design method based on an extended design space is proposed to optimize the design complexity and linearization performance of conventional linearizers for broadband operation. The gain characteristics of the power amplifier (PA) and linearizer are fitted to simplify the analyses and to quickly derive the ideal objective function of the linearizer design. Then, the 1 dB compression point of a nonlinear system is redefined and used to further extend the design space of the linearizer. To verify the proposed design method, a millimeter-wave linearizer prototype based on the extended design space was designed and fabricated. The linearizer was tested with continuous-wave and 100 MHz two-tone signals from 40 GHz to 43 GHz. The measurement results of the linearized PA showed that the output 1 dB power point (OP1dB) was improved by more than 1.7 dB, the phase error was reduced by more than 15°, and the third-order intermodulation distortion (IMD3) was suppressed by 8.6 dB–13.1 dB over the working frequencies. The proposed linearizer achieved good linearization performance, low power consumption, and simple design implementation, and it was not necessary to tune the bias during broadband operation, making it applicable in complex communication scenarios.

A novel design model of flow channel paths for additive manufacturing

Purpose This paper aims to propose a method for automatic design of additive manufacturing (AM) flow channel paths driven by path length and pressure loss. The research focuses on the automatic design of channel paths, intending to achieve the shortest flow channel length or minimum pressure loss and improve the design efficiency of AM parts. Design/methodology/approach The initial layout of the flow channels is redesigned to consider the channels print supports. Boundary conditions and constraints are defined according to the redesigned channels layout, and the equation consisting of channel length and pressure loss is used as the objective function. Then the path planning simulation is performed based on particle swarm algorithm. The proposed method describes the path of flow channels using spline cures. The spline curve is controlled by particle (one particle represents a path), and the particle is randomly generated within the design space. After the path planning simulation is completed, the generated paths are used to create 3D parts. Findings Case study 1 demonstrates the automatic design of hydraulic spool valve. Compared to conventional spool valve, the pressure loss was reduced by 86% and the mass was reduced by 83%. The design results of case study 2 indicate that this approach is able to find the shortest channel path with lower computational cost. Originality/value The automatic design method of flow channel paths driven by path length and pressure loss presented in this paper provides a novel solution for the creation of AM flow components.

Hybrid control for non-overshooting step responses of linear systems

This paper focuses on the problem of applying hybrid control to overcome overshoot performance limitations of linear time-invariant (LTI) systems, and puts forward a systematic method for the joint design of a hybrid controller. By modeling the whole closed-loop system in the framework of a hybrid system, an input-to-state stable (ISS) criterion for the system is established, and on the basis of this, conditions for non-overshooting step responses are obtained. In the proposed hybrid controller, apart from its input and output information, state information of the LTI plant and a basic LTI controller is used to design flow and jump sets. The advantage is that when the trigger matrix of flow and jump sets is unknown, it can be designed conveniently. Based on the conditions, the hybrid controller synthesis is formulated in linear matrix inequalities and the algorithm of solving controller matrices and the triggering matrix is given. In addition, the design method of the hybrid controller with a certain triggering matrix is derived. The effectiveness and reliability of the obtained results are demonstrated through a numerical example.

Fusion design of six-port waveguide coupler integrating tight and loose coupling

This paper introduces a fusion design method of a six-port waveguide (WG) coupler integrating tight and loose coupling together. The couplers exhibit a compact size due to the stacked configuration of three WGs. A methodology for designing the integrating tight and loose coupler is presented. The tight and loose coupling is achieved by setting a rectangular slot in the common narrow wall along with one or two cross slots in the common broad wall. Inspired by the superposition of TE10 and TE20 modes used to design the short-slot −3-dB coupler. The loose-coupling part of the fusion design is analyzed theoretically utilizing modes superposition. Based on the theoretical analysis, the loose coupling can be precisely designed, meanwhile, low coupling-level fluctuation can be obtained in the operating band. For demonstration, two design examples are designed and a prototype centered at about 3.73 GHz is fabricated. The fractional bandwidth (FBW) (|S11| < −15 dB) is about 28.4 %. Within it, the tight coupling (−3 dB) coupler achieves ± 0.5 dB amplitude imbalance. Meanwhile, the loose coupling (−20 dB) coupler achieves little fluctuation of < 0.56 dB and its isolation is better than 25 dB.

A new multi-input multi-output control design method for a large-scale web transport system

The paper introduces an innovative multi-input multi-output (MIMO) control design approach tailored for the complex dynamics of large-scale web transport systems in printed electronics manufacturing technology. First, a novel hybrid control design is proposed to a MIMO strict-feedback nonlinear dynamic system, in which a modified tracking error is introduced in term of a sliding surface for design purpose. Then, a combined use of Lyapunov-based control design and sliding mode control is employed to formulate a novel control law, called Backstepping Sliding Mode Control (BSMC) and a BSMC based control structure is provided. Second, application of this control strategy is implemented to control web tension and velocity of a three-span web transport system. In this study, a series of assumptions are provided to transform an original system dynamics of web transport system into a standard strict-feedback form. Then, the proposed theory is applied for the achieved system, a BSMC for the system is synthesized for simulation study. Finally, numerical simulations are conducted under different operating conditions to validate the effectiveness, reliability, and robustness of the proposed control method.

Fuzzy control for networked systems with mixed data missing under quantization based event-triggered scheme

This paper presents an innovative event-triggered fuzzy control approach for networked systems operating over unreliable network channels. Traditional complicated modeling and analysis process of network induced issues is replaced by a bran-new logarithmic quantization based event-triggered scheme method. The joint characterization of mixed data missing, arising from the event-triggered mechanism and unreliable network channels, becomes a challenging issue due to disrupted data sequences and variable relations. Consequently, this paper contributes a formulated auxiliary stochastic sequence approach to overcome the difficulty of dynamics modeling. With an formulated event driven controller, the modeling and implementation of the closed-loop systems are constructed and further simplified. Considering the difference and relation between the membership functions of plant and controller, we present a new fuzzy output feedback controller design method to obtain feasible result via uncertainty based method. Finally, we verify the validity of the designed control policy via a simulation example.

Initial tweet valence, abuse volume, and observer Dark Tetrad characteristics influence perceptions of female celebrity abuse on Twitter

Research into relationships between victim-generated content, abuse received, and observer characteristics when considering Twitter abuse has been limited to male victims. We evaluated participant perceptions of female celebrity victims and abuse received on Twitter. We used a 3 (Initial Tweet Valence; negative, neutral, positive) × 2 (Abuse Volume; low, high) repeated measures design and online survey method. Participants were shown tweets generated by six female celebrities, counterbalanced such that each participant saw each celebrity in one Valence-Volume condition. Stimuli were presented across six ‘lists’ such that celebrity ‘victims’ could be rotated across Valence-Volume pairings. Participants rated—per target stimulus—the level of blame attributable to the victim and the perceived severity of the incident. Furthermore, participants were asked to complete a Dark Tetrad scale—measuring their Machiavellianism, Narcissism, Psychopathy, and Sadism. Analyses determined that victim-blaming was influenced by victim Initial Tweet Valence (greater victim-blaming associated with more-negative content) and observer Machiavellianism. Perceived severity was influenced by victim Initial Tweet Valence, Volume of Abuse received, and observer Machiavellianism. Results were consistent with previous research involving male celebrity victims. Further research is needed to understand the contributions of participants’ hostile and benevolent sexism, as well as the role of victim attractiveness.

Evaluation and Analysis of the Effects of Feed Supplements, Including both Organic and Inorganic Selenium, on the Production of Layer Eggs

This research aims to evaluate and analyze the provision of additional feed in the form of selenium (Se) on the performance of egg production produced by layers. This research took the main object in the form of 60 weeks old laying hens with the Isa Brown strain. The research was carried out using a Completely Randomized Design (CRD) method with Duncan’s advanced test. The results of this study explain that providing additional feed in the form of selenium (Se) in several doses has a very real influence on egg production performance (egg weight, feed intake, mortality, daily egg production, and FCR). The best dose of selenium was shown in treatment three (commercial feed + organic selenium dose of 150 grams/ton of inorganic selenium feed + vitamin E dose of 1000 grams/ton of feed). The presence of selenium and vitamin E given as additional feed for laying hens can increase egg weight, egg production, minimize mortality rates, and increase appetite.

Disturbance rejections of polynomial fuzzy systems under equivalent-input-disturbance estimator approach

This paper proposes an integrated robust stabilization and anti-disturbance control scheme for nonlinear systems using a polynomial fuzzy model approach. To estimate unknown disturbances, an equivalent-input-disturbance (EID) estimator is employed. The proposed approach incorporates a novel fuzzy model assisted by EID estimator into the sum-of-squares-based approach, utilizing a polynomial fuzzy model-based observer to estimate the disturbance effect. A suitable fuzzy rule-based control law is developed by utilizing the parallel distributed compensation approach and the output of the EID estimator. To ensure stability, fuzzy membership functions are converted into sum-of-square polynomials using a polynomial curve fitting approach, allowing their exact shape information to be used in the stability condition. The addressed system is transformed into an augmented system by incorporating the system, observer, and filter states, simplifying the analysis. Gain matrices for the controller and observer are obtained using Lyapunov stability theory and sum-of-squares methods to confirm asymptotic stabilization of the fuzzy system. Two numerical examples are presented to demonstrate the effectiveness of the proposed control design method.

Atık mermer tozu ile zemin stabilizasyonunun mekanistik-amprik tasarım yöntemine göre incelenmesi

Mermer kullanımının artmasına bağlı olarak, ortaya çıkan mermer atıkları dünya çapında önemli bir çevre sorunu haline gelmiştir. Sürdürülebilirliğin önemli olduğu günümüzde bu tür atıklar inşaat işlerinde çeşitli amaçlar için kullanılmaktadır. Sürdürülebilirliğe en büyük katkı, atık maddelerin yeniden kullanımıdır. Yapılan deneysel ve hesaplamalı çalışmada, üç farklı atık mermer tozunun zemin stabilizasyon malzemesi olarak kullanılabilirliği araştırılmıştır. Çalışmanın deneysel kısmında atık mermer tozları % 0-10-20-30 ve 40 oranlarında iki farklı CL sınıfı killi zemine eklenmiş ve zeminlerin mukavemet özelliklerindeki değişiklikler Atterberg limitleri, standart Proctor sıkıştırma, kesme kutusu, ve Kaliforniya taşıma oranı (CBR) testleri ile izlenmiştir. Hesaplamalı kısımda ise CBR ve AASHTO-93yöntemleri kullanılarak yapılan stabilizasyonun üstyapı kalınlığına etkileri belirlenirken, KENPAVE yazılımı ile Mekanistik-Amprik tasarım metoduna uygun olarak mermer tozu iyileştirmesinin üstyapının yorulma ömrüne olan katkısı araştırılmıştır. Elde edilen test sonuçları mermer toz atıklarıyla stabilize edilen düşük plastisiteli killerin dayanım özelliklerinin iyileştiğini göstermiştir. CBR ve AASHTO-93 metotları ile bu iyileştirmenin gereken üstyapı kalınlığını azaltabileceği, SN sayısındaki azalma ile karayolu imalatında yüzlerce metreküp malzeme kazancı sağlanabileceği hesaplanmıştır. Mekanistik-Amprik yöntem ile yapılan hesaplar da atık mermer tozu stabilizasyonu ile üstyapının kritik tekerlek izi oturması ömrünün ortalama %86’ya kadar artabileceğini öngörmektedir.

Design of an optically transparent and broadband absorber based on a multi-objective optimization algorithm.

In this Letter, an optically transparent and broadband absorber designed using a multi-objective genetic algorithm (MOGA) is proposed. The absorption of the multilayer lossy frequency selective surface-based absorber is calculated by multilayer absorption equations and equivalent circuit models. To solve the problem of the unbalanced structure absorption bandwidth and thickness, an algorithm is used for optimizing the geometric and sheet resistance parameters of the structure. A multilayer and optically transparent absorber with 90% absorption bandwidth covering a frequency range of 2-18 GHz (S-band to Ku-band) is developed based on the MOGA design method with optical transmittance of 60%. Its total thickness consists of a wavelength of only 0.095, and it has high oblique incidence stability, which makes it useful in the stealth technology and transparent electromagnetic shielding applications.

A Review on Structural Configurations of Magnetorheological Clutch

Abstract:: In recent years, with the development of "smart materials", magnetorheological fluids have been widely used in the fields of mechanical transmission, aerospace, construction, and medical treatment because of the unique rheological properties that can occur under the action of an applied magnetic field. Magnetorheological clutches with magnetorheological fluid as the working medium have the advantages of simple structure, low noise, fast response, and easy control compared with traditional clutches. In order to provide an overview of the issues encountered by magnetorheological clutches in their current applications and to summarize the optimization designs implemented to address these issues, with the aim of promoting the widespread application of magnetorheological clutches. The basic theory of magnetorheological fluid and magnetorheological clutch design method is introduced. The related patents of magnetorheological clutch structure design are reviewed. The characteristics and advantages of magnetorheological clutch in different working modes are summarized. This study introduces the basic theory of magnetorheological fluid. The problems existing in the application of magnetorheological clutch are explained. The characteristics of magnetorheological clutch based on shear mode, shear-extrusion mode and heat dissipation mode are described. The development trend of magnetorheological clutch is discussed. This paper provides an important basis for the design and application of magnetorheological clutch, offers specific guidance for improving the torque transmission capacity and heat dissipation capacity of magnetorheological clutch, and lays a theoretical foundation for the wide application of magnetorheological clutch in the future.

Design Method of Cam Steering Mechanism Based on Path Fitting

In order to improve the accuracy of a solar-powered punch card car’s movement on a designated route and reduce positional deviations during its operation, a solar-powered punch card car with a single cam as the steering guidance mechanism was designed. The car adopts a three-wheel structure. The transmission mechanism, steering mechanism, driving mechanism, and regulating mechanism of the car were analyzed. The kinematics model of the car was established and the motion characteristics of the car were obtained. By analyzing the relationship between the steering angle of the car and the curvature radius of its travel route, the front wheel angle of the car at each position was calculated using MATLAB R2020a. This allowed us to establish the relationship between the front wheel angle and the displacement of the steering push rod, which was further converted into the theoretical contour line of the cam. Subsequently, the theoretical contour line of the cam was completed and envelope correction was performed. Finally, through mechanical analysis and experimental verification using a prototype, the results indicated that the single-cam steering guidance mechanism calculated using this fast path fitting method exhibited excellent mechanical performance and a smooth and accurate trajectory, and the traveling path of the theoretical cam contour curve was basically consistent with the actual trajectory route.

Students’ Perceived Role of Rote Learning in Vocabulary Learning Strategies at Secondary Level

This paper aims to examine the students’ perceived role of rote learning strategy for learning English vocabulary at secondary level. 1497 mixed-ability public and private secondary school students of district Multan were used to gather information. Respondents in age range from 12 to 18 years. The findings were collected through the adapted questionnaires. English version with Urdu translation was administered to participants and a proportional stratified random sampling technique was implemented. Survey method of quantitative design was used in this study. The data were analyzed using descriptive and inferential statistical approaches, including Pearson's R correlations, Mean, SD, Independent samples t-test, and ANOVA. Factor analysis was also performed. Findings showed positive behavior of students’ towards using vocabulary learning strategies. It was concluded that students’ perceived the most effective role of rote learning in vocabulary learning strategies at secondary level then other vocabulary learning strategies. Significant correlation was found between students’ perception of vocabulary learning strategies and students’ perception of preferring rote learning strategy. It was found that students’ perception of vocabulary learning strategies with respect to School Sector, Gender, Group, Medium, Tehsil, Father’s Qualification and Mother’s Qualification varies significantly while students’ perception of vocabulary learning strategies based on Class and Age are not varied significantly. No statistically significant differences was found between students’ perception of preferring rote learning strategy with respect to School Sector, Class, Gender, Tehsil, Father’s Qualification and Mother’s Qualification. Furthermore students’ perception of preferring rote learning strategy based on Group, Medium and Age differs significantly.

Ultra-Wideband Vertical Transition in Coplanar Stripline for Ultra-High-Speed Digital Interfaces.

A design method for an ultra-wideband coplanar-stripline-based vertical transition that can be used for ultra-high-speed digital interfaces is proposed. A conventional via structure, based on a differential line (DL), inherently possesses performance limitations (<10 GHz) due to difficulties in maintaining constant line impedance and smooth electric field transformation, in addition to the effects of signal skews, FR4 fiber weave, and unbalanced EM interferences. DL-based digital interfaces may not meet the demands of ultra-high-speed digital data transmission required for the upcoming 6G communications. The use of a coplanar stripline (CPS), a type of planar balanced line (BL), for the vertical transition, along with the ultra-wideband DL-to-CPS transition, mostly removes the inherent and unfavorable issues of the DL and enables ultra-high-speed digital data transmission. The design process of the transition is simplified using the analytical design formulas, derived using the conformal mapping method, of the transition. The characteristic line impedances of the transition are calculated and found to be in close agreement with the results obtained from EM simulations. Utilizing these results, the CPS-based vertical transition, maintaining the characteristic line impedance of 100 Ω, is designed and fabricated. The measured results confirm its ultra-wideband characteristics, with a maximum of 1.6 dB insertion loss and more than 10 dB return loss in the frequency range of DC to 30 GHz. Therefore, the proposed CPS-based vertical transition offers a significantly wider frequency bandwidth, i.e., more than three times that of conventional DL-based via structures.

Reverse optimization design of OAM sound barrier based on acoustic metamaterials

An optimized acoustic metamaterial (OAM) railway sound barrier has been designed to address the growing noise problem in railway construction. The low-frequency broadband noise attenuation is realized by an reverse design method relying on genetic algorithm-neural network (GA-NN). Simulation results show that the OAM can perfectly cover the target frequency band from 400 Hz to 1000 Hz with a bandgap ranging from 210 Hz to 1253 Hz. Compared with the initial acoustic metamaterial (IAM), the bandgap of the OAM is widened by 1295 Hz, and the sound transmission loss is improved by 15 dB. The noise reduction performance of the OAM is verified by the experiments of the fully-enclosed impedance tube and the simulation of the acoustic field modes. The acoustic experiments of the semi-enclosed OAM sound barriers show that the noise reduction of OAM sound barriers has a low-frequency broadband noise reduction effect. Compared with the existing sound barriers, the average noise reductions of OAM sound barriers in the target frequency band and bandgap range are improved to 15.9 dB and 7.8 dB, respectively.

Multi-objective design of parametric equivalent-input-disturbance approaches with application to vehicle suspension systems

A multi-objective parametric design method is developed for an equivalent-input-disturbance-based control system with mismatched disturbances. Different from the existing design methods that calculated control parameters by stability conditions, multiple performance objectives including unmeasurable output estimation, disturbance rejection, noise suppression, input refinement, and robustness, are simultaneously optimized in the developed design. First, for the sake of low computation complexity, the closed-loop system is represented. Then, the parameterization of the design conditions for multiple performance objectives is given. Further, a nonlinear optimization method is used to perform the performance-oriented system design. Lastly, the efficacy and benefits of the developed methods are demonstrated through simulations of a quarter-vehicle suspension system and comparisons with other alternative methods.

Novel tuning rules for IMC-high-order PID load frequency controller of power systems

The problem of load frequency control (LFC) for power grids has received widespread attention in power industrial control. Ensuring the stability of the frequency is the primary concern that constrains the development of the electric power system. This paper presents a novel internal model control (IMC)- proportional-integral-derivative (PID) controller design method for LFC control systems, centered on pole-zero conversion. This method aims to simplify the system model's complexity and improve the system's performance. The IMC controller is approximated as a PID series compensator (high-order PID), with exact tuning formulas provided for various scenarios. These include single-area without or with reheat turbines, hydro turbines with transient droop compensators, wind turbines, and gas turbines. The tuning formulas are characterized by a single parameter, determined under robustness constraints and integrated time absolute error (ITAE). The proposed tuning method considers the generator rate constraint (GRC) and applies to multi-area single-source and multi-area multi-source power systems. The results of the simulation confirm that the controller tuning method presented in this paper has significant advantages over the existing design methods concerning robustness and anti-interference performance.

Reflecting optical systems desensitization: Modulation by freeform surfaces

Freeform surfaces have been used to achieve high imaging performance in recent years. Apart from the nominal performance, sensitivity is a vital factor for the realizability of the as-built performance. We found that freeform surfaces are not only excellent for aberration correction but also enable the achievement of desensitization. In this paper, two merit functions, FDS and SDS, are established, and a desensitization design method that performs desensitization modulation by using freeform surfaces (DMF), is proposed. This method elucidates the reasons behind freeform surfaces enabling low sensitivity and taps into the desensitizing potential of freeform surfaces. We used the Tianwen-1 High-Resolution Imaging Camera (HiRIC) optical system as the prototype and achieved a 42.14 % reduction in sensitivity by using the DMF design method we proposed.