Local Control Method Research Articles

Traffic signal optimization on a square lattice with quantum annealing

The spread of intelligent transportation systems in urban cities has caused heavy computational loads, requiring a novel architecture for managing large-scale traffic. In this study, we develop a method for globally controlling traffic signals arranged on a square lattice by means of a quantum annealing machine, namely the D-Wave quantum annealer. We first formulate a signal optimization problem that minimizes the imbalance of traffic flows in two orthogonal directions. Then we reformulate this problem as an Ising Hamiltonian, which is compatible with quantum annealers. The new control method is compared with a conventional local control method for a large 50-by-50 city, and the results exhibit the superiority of our global control method in suppressing traffic imbalance over wide parameter ranges. Furthermore, the solutions to the global control method obtained with the quantum annealing machine are better than those obtained with conventional simulated annealing. In addition, we prove analytically that the local and the global control methods converge at the limit where cars have equal probabilities for turning and going straight. These results are verified with numerical experiments.

Comprehensive Comparative Analysis of Local False Discovery Rate Control Methods.

Due to the advance in technology, the type of data is getting more complicated and large-scale. To analyze such complex data, more advanced technique is required. In case of omics data from two different groups, it is interesting to find significant biomarkers between two groups while controlling error rate such as false discovery rate (FDR). Over the last few decades, a lot of methods that control local false discovery rate have been developed, ranging from one-dimensional to k-dimensional FDR procedure. For comparison study, we select three of them, which have unique and significant properties: Efron’s approach, Ploner’s approach, and Kim’s approach in chronological order. The first approach is one-dimensional approach while the other two are two-dimensional ones. Furthermore, we consider two more variants of Ploner’s approach. We compare the performance of those methods on both simulated and real data.

Эмбриональная рабдомиосаркома влагалища

Vaginal embryonal rhabdomyosarcoma is a relatively rare tumor, which is more commonly diagnosed in children under three years of age and is rarely associated with organ-sparing treatment. Neoadjuvant chemotherapy followed by radiotherapy or surgery can be currently used as local tumor control. A clinical case of vaginal embryonal rhabdomyosarcoma in a 5-year-old girl is presented. Considering the tumor response to polychemotherapy, high dose rate intracavitary radiation therapy (brachytherapy) was chosen as the method of local control. Brachytherapy reduces the need for surgery and radiation of large regions in children and enables young patients to realize their reproductive function in the future. Key words: brachytherapy, management strategies, embryonal rhabdomyosarcoma

Diagnostic possibilities of laboratory assessment of cathepsin K activity in gingival and peri-implant fluid under normal conditions and periimplantitis

The aim of the work was to develop a non-invasive laboratory method for local control of the severity of osteo-destructive processes in the bone tissue of the jaws after dental implantation. The study comprised 75 individuals aged 18 to 65. The main group included 40 patients with a diagnosis of dental periimplantitis (ICD K 10.2). A comparison group (n=20) included patients after dental implantation without postoperative complications. The control group (n=25) consisted of individuals without dental pathology. Cathepsin K (CTSK) (Human) ELISA Kit (Cloud-Clone Corp., USA) was used to determine the concentration of cathepsin K by the enzyme immunoassay in the gingival or peri-implant fluid. The concentration of cathepsin K in the gingival fluid in the patients of the control group was 1.7±0.3 pmol/l, in the comparison group the concentration of the studied biomarker corresponded to 2.3±0.4 pmol/l. In the main group, the concentration of cathepsin K in the exudate of peri-implantation pockets increased 2.8 times (p<0.05) and corresponded to 4.9±0.5 pmol/l. The concentration of cathepsin K in the gingival fluid normally did not depend on age and gender, which increased the independence of the osteomarker for characterizing the osteoresorbent process in the peri-implantation area. After dental implantation, an excess of cathepsin K concentration above the level of 2.7 pmol/l with a diagnostic sensitivity of 82.5% and a specificity of 83.7% suggests a high risk of developing peri-implantitis. The concentration of cathepsin K may be seen as valuable marker for local inflammatory and destructive processes in the contents of the peri-implantation area.

A Hybrid Active Noise Control System for the Attenuation of Road Noise Inside a Vehicle Cabin.

This paper proposed a local active control method for the reduction of road noise inside a vehicle cabin. A multichannel simplified hybrid active noise control (sHANC) system was first developed and applied to the rear left seat of a large sport utility vehicle (SUV). The attenuation capability of the sHANC system was investigated through simulations, using reference signals provided by accelerometers on the suspensions and bodywork of the vehicle and microphones on the floor of cabin, respectively. It was shown that compared to the traditional feedforward system, the sHANC system using either vibrational or acoustical reference signals can produce a significant suppression of the narrowband peak noise between 75 and 80 Hz, but the system lost the control capability in a range of 100–500 Hz when the acoustic signals were used as references. To reduce the practical implementation costs while maintaining excellent reduction performance, a modified simplified hybrid ANC (msHANC) system was further proposed, in which combined vibrational and acoustical signals were used as reference signals. The off-line analyses showed that four reference accelerometers can be substituted by ten microphones without compromising attenuation performance, with 3.7 dBA overall noise reduction being achieved. The effect of delays on the reduction performance of msHANC system was also investigated. The result showed that the msHANC system was more sensitive to the delays compared to the sHANC system if using only vibrational reference signals.

Gradient-Limiting Shape Control for Efficient Aerodynamic Optimization

Local shape control methods, such as B-spline surfaces, are well-conditioned such that they allow high-fidelity design optimization; however, this comes at the cost of degraded optimization convergence rate as control fidelity is refined due to the resulting exponential increase in the size of the design space. Moreover, optimizations in higher-fidelity design spaces become ill-posed due to high-frequency shape components being insufficiently bounded; this can lead to nonsmooth and oscillatory geometries that are invalid in both physicality (shape) and discretization (mesh). This issue is addressed here by developing a geometrically meaningful constraint to reduce the effective degrees of freedom and improve the design space, thereby improving optimization convergence rate and final result. A new approach to shape control is presented using coordinate control () to recover shape-relevant displacements and surface gradient constraints to ensure smooth and valid iterates. The new formulation transforms constraints directly onto design variables, and these bound the out-of-plane variations to ensure smooth shapes as well as the in-plane variations for mesh validity. Shape gradient constraints approximating a continuity condition are derived and demonstrated on a challenging test case: inviscid transonic drag minimization of a symmetric NACA0012 airfoil. Significantly, the regularized shape problem is shown to have an optimization convergence rate independent of both shape control fidelity and numerical mesh resolution, while still making use of increased control fidelity to achieve improved results. Consequently, a value of 1.6 drag counts is achieved on the test case, the lowest value achieved by any method.

Incursion pathways of the Asian tiger mosquito (Aedes albopictus) into Australia contrast sharply with those of the yellow fever mosquito (Aedes aegypti)

Understanding pest incursion pathways is critical for preventing new invasions and for stopping the transfer of alleles that reduce the efficacy of local control methods. The mosquitoes Aedes albopictus (Skuse) and Ae. aegypti (Linnaeus) are both highly invasive disease vectors, and through a series of ongoing international incursions are continuing to colonize new regions and spread insecticide resistance alleles among established populations. This study uses high-resolution molecular markers and a set of 241 reference genotypes to trace incursion pathways of Ae. albopictus into mainland Australia, where no successful invasions have yet been observed. We contrast these results with incursion pathways of Ae. aegypti, investigated previously. Assignments successfully identified China, Japan, Singapore and Taiwan as source locations. Incursion pathways of Ae. albopictus were entirely different to those of Ae. aegypti, despite broad sympatry of these species throughout the Indo-Pacific region. Incursions of Ae. albopictus appeared to have come predominantly along marine routes from key trading locations, while Ae. aegypti was mostly linked to aerial routes from tourism hotspots. These results demonstrate how genomics can help decipher otherwise cryptic incursion pathways. The inclusion of reference genotypes from the Americas may help resolve some unsuccessful assignments. While many congeneric taxa will share common incursion pathways, this study highlights that this is not always the case, and incursion pathways of important taxa should be specifically investigated. Species differences in aerial and marine incursion rates may reflect the efficacy of ongoing control programmes such as aircraft disinsection. © 2020 Society of Chemical Industry.

Online trajectory planning and control of a MAV payload system in dynamic environments

Micro Aerial Vehicles (MAVs) can be used for aerial transportation in remote and urban spaces where portability can be exploited to reach previously inaccessible and inhospitable spaces. Current approaches for path planning of MAV swung payload system either compute conservative minimal-swing trajectories or pre-generate agile collision-free trajectories. However, these approaches have failed to address the prospect of online re-planning in uncertain and dynamic environments, which is a prerequisite for real-world deployability. This paper describes an online method for agile and closed-loop local trajectory planning and control that relies on Non-Linear Model Predictive Control and that addresses the mentioned limitations of contemporary approaches. We integrate the controller in a full system framework, and demonstrate the algorithm’s effectiveness in simulation and in experimental studies. Results show the scalability and adaptability of our method to various dynamic setups with repeatable performance over several complex tasks that include flying through a narrow opening and avoiding moving humans.

Local reactive power dispatch optimisation minimising global objectives

The number of distributed energy resources (DERs) deployed in distribution systems has been rapidly increasing in recent years. Consequently, many researchers have proposed to utilise the DERs for local reactive power support. Yet, the expansion of infrastructure necessary to allow communication among the DERs, and with a centralised controller, has not been as fast. This necessitates an independent local control method that is able to fulfil the objectives of a centralised controller. Therefore, this work proposes a data-driven local optimisation of global objectives (LOGO) algorithm to control the reactive power dispatch from DERs in distribution systems. The proposed method has been validated across different test systems with real topology, irradiance and load data, for steady-state undervoltage and overvoltage scenarios. The results have shown that LOGO performs almost as well as centralised optimisation without any communication and without any information regarding the grid topology. LOGO is able to satisfy the voltage constraints using only locally available information even when other algorithms fail to do so. Compared with distributed and other local reactive power controls, LOGO is much more stable and yields significantly better results. Moreover, LOGO’s superiority over other control methods increases with system size and complexity. Hence, this work provides a viable alternative for real-life dispatch optimisation and opens up new possibilities to optimise global variables without any communication. Lastly, this paper also highlights the importance of accurate solar forecasting and validation of reactive power control.

Combination of ALA-induced fluorescence-guided resection and intraoperative open photodynamic therapy for recurrent glioblastoma: case series on a promising dual strategy for local tumor control.

High-grade glioma (HGG) prognosis remains dismal, with inevitable, mostly local recurrence. Regimens for improving local tumor control are therefore needed. Photodynamic therapy (PDT) using porfimer sodium has been investigated but was abandoned due to side effects and lack of survival benefits. Intracellular porphyrins induced by 5-aminolevulinic acid (5-ALA) are approved for fluorescence-guided resections (FGRs), but are also photosensitizers. Activated by light, they generate reactive oxygen species with resultant cytotoxicity. The authors present a combined approach of 5-ALA FGR and PDT. After 5-ALA FGR in recurrent HGG, laser diffusors were strategically positioned inside the resection cavity. PDT was applied for 60 minutes (635 nm, 200 mW/cm diffusor, for 1 hour) under continuous irrigation for maintaining optical clarity and ventilation with 100% oxygen. MRI was performed at 24 hours, 14 days, and every 3 months after surgery, including diffusion tensor imaging and apparent diffusion coefficient maps. Twenty patients were treated. One surgical site infection after treatment was noted at 6 months as the only adverse event. MRI revealed cytotoxic edema along resection margins in 16 (80%) of 20 cases, mostly annular around the cavity, corresponding to prior laser diffusor locations (mean volume 3.3 cm3). Edema appeared selective for infiltrated tissue or nonresected enhancing tumor. At the 14-day follow-up, enhancement developed in former regions of edema, in some cases vanishing after 4-5 months. Median progression-free survival (PFS) was 6 months (95% CI 4.8-7.2 months). Combined 5-ALA FGR and PDT provides an innovative and safe method of local tumor control resulting in promising PFS. Further prospective studies are warranted to evaluate long-term therapeutic effects.

A New Local Control Method of Interlinking Converters to Improve Global Power Sharing in an Islanded Hybrid AC/DC Microgrid

We propose a new local controller to determine the active power reference for an interlinking converter (IC) of an islanded hybrid ac/dc microgrid (IHMG). The main objective of the proposed method is to improve the accuracy of global power sharing (GPS) between distributed generators throughout an IHMG to enhance the reliability and stability. Based on our analysis of the required active power of ICs for GPS, a local IC controller is proposed to enable parallel IC operation and improve GPS. The effects of the proposed controller on the system stability and GPS accuracy are also analyzed using a small-signal model. Furthermore, we provide guidelines on how to determine an appropriate control parameter for the proposed controller based on the desired GPS accuracy and the stability margin. Finally, the proposed method is verified by Simulink/MATLAB and hardware-in-the-loop experimental platform.

Simulation and experiment on tonal vibration transmission control with a multi-channel global control method

A multi-channel global control method is proposed in combination with active isolators to suppress tonal vibration transmission in structures. This method is built on a modified adaptive control algorithm and the mutual interferences in control channels are compensated. The efficacy of the global control method is investigated by using a mechanical system, which consists of a hull structure, a controllable vibration source and four active mounts. A dynamic model of the mechanical system is established and the results of numerical simulation indicate that the global control method is more effective as the channel interferences are compensated and the convergence rate of it is faster than the local control method, which considers the local vibration feedback only. Experimental results also demonstrate that the global control method is able to suppress tonal vibration transmission effectively, even in the circumstance of strong mutual interferences in control channels.

Multi‐mode adaptive local reactive power control method based on PV inverters in low voltage distribution networks

Low voltage distribution networks with the high penetration of photovoltaic (PV) units are facing four types of challenges, including over-voltage issues, under-voltage issues, voltage fluctuation issues and high power losses. In order to mitigate the above issues, this study proposes a multi-mode adaptive local reactive power control method based on Q(P) characteristics. A new concept, node virtual injection active power (NVIP), is developed to take the PV active power, load active power and load reactive power as a whole and as the basis to regulate the PV reactive power. Then, an NVIP-based multi-mode local Q(P) framework is proposed to consider the four types of challenges based on four operation modes, respectively, that can be adaptively switched according to the NVIP value and the NVIP variation. In addition, a systematic parameter design for the Q(P) framework is proposed based on an optimisation model to further enhance the effectiveness of the proposed multi-mode control. The simulation results demonstrate the effectiveness of the proposed method in mitigating voltage violations and voltage fluctuations, and improving the power losses and power factor.

Thermal Ablation for Small Papillary Thyroid Cancer: A Systematic Review.

Background: Although clinical studies indicate that thermal ablation is effective in treating low-risk papillary thyroid microcarcinomas (PTMCs), the effectiveness of this treatment in patients with low-risk PTMC has not yet been systematically evaluated. Methods: Ovid-MEDLINE and EMBASE databases were searched for studies published through May 1, 2019, which report the efficacy of thermal ablation in patients with low-risk PTMCs. Data were extracted and methodological quality was assessed independently by two radiologists according to PRISMA guidelines. Results: This systematic review identified 503 low-risk PTMCs in 470 patients treated by thermal ablation from 9 studies. During follow-up, no patient experienced local tumor recurrence or distant metastasis, whereas two patients (0.4%) experienced lymph node (LN) metastasis. One patient (0.2%) developed a new PTMC, which was successfully treated by additional ablation. Five patients (1.1%) underwent delayed surgery after ablation, including the two patients with LN metastasis and three additional patients with unknown etiology. Conclusions: Thermal ablation is an excellent local tumor control method in patients with low-risk PTMCs. Strict inclusion criteria and technical expertise are required to obtain favorable results.

A Design of Standalone Hybrid PV/Wind/Fuel cell Generation System and Hydrogen Electrolyzer With Local Controller for Remote Areas

Integration of fuel cell and electrolyzer on DC bus is a promising alternative to solve voltage fluctuation and balance of power problems in a standalone hybrid renewable power generation systems. The hybrid renewable power generation systems consist of photovoltaic, wind turbine, fuel cell and hydrogen electrolyzer. Each the component integrated on DC bus through the converter DC – DC using local controller to supply the inverter which connected to the islanded load. Local controller in each part will make the system become flexible if there are additional generating units in the future. The local control methods used in this hybrid renewable power generation system is MPPT and constant voltage control. MPPT control applied to photovoltaic and wind turbine converters to maximize power generation from photovoltaic and wind turbine. Constant voltage controller applied to the fuel cell and electrolyzer converters to control the DC bus voltage alternately. This research is a new design system for remote areas by utilizing the potensial of renewable energy in the area. The result show the power quality and continuity of electricity services.

A transient heat current model for dynamic performance analysis and optimal control of heat transfer system

Taking dynamic characteristic into consideration to realize performance prediction and optimal control of heat transfer systems is significant for energy conservation. This paper first proposes a transient heat current model of heat exchanger to clearly express the relation of different variables at unsteady state. Then, utilizing the topological relations of every heat exchanger in heat transfer systems forms the transient heat current models and derives the integrated constraint equations to reflect the system heat transfer and storage laws, which further offers the state equation and the output equation to reflect the interrelation of different system parameters. Applying these equations yields an integrated control method to realize the optimal control of heat transfer systems by taking the interaction of multiple control variables and objectives into consideration. For a four-loop heat transfer system, the newly proposed integrated control method with optimized intermediate temperatures reduces 25.7% of the total pumping power comparing to that obtained by a traditional local control method with preset intermediate temperatures, which shows the capability and superiority of the newly proposed method.

Wide Area Predictive Control of Power System Considering Communication Delay and Data Drops

Wide area control (WAC) is an efficient technique to damp out low frequency oscillation of power system. In this process, the communication delay (constant and random) and multiple data drops in control input signals are major issues. To overcome these problems, in this paper, a wide area predictive control (WAPC) strategy is proposed for power system with lines having thyristor controlled series compensation (TCSC). This method establishes a predictive algorithm that uses variable weighting sequence for an available data window with higher weights to the recent data. Thereby, the proposed method is able to track sudden changes in power system operating conditions satisfactorily. In case of WAPC detects nonavailability of any data in a window, the predicted data for the window are used to fill these gaps. In this way, the proposed approach compensates the data drop(s). The effectiveness of the proposed WAPC is tested for the 39-bus New England system and compared with the local control, WAC, and network predictive control method.

Survival and factors affecting the outcome of synovial sarcoma in children and adolescents single institute experience

Introduction: To check the impact of the clinical and pathologic features at diagnosis and treatment given, on the outcome of synovial sarcoma in children and adolescents.Methods: Retrospective analysis of patients below 18 years old diagnosed by synovial sarcoma and treated at Children CancerHospital Egypt 57,357 (CCHE) between July 2007 and December 2016. We reviewed Clinical characteristics, pathological information, treatment modalities and survival data.Results: We included thirty one patients with median age at diagnosis was 14.8 years. Initial surgical excision was possible in 10 patients (58.8%) while 5 (29.4%) patients underwent surgical excision after response to preoperative chemotherapy. Two patients had unresectable tumor, showed no response to chemotherapy and received radiotherapy as the only local control therapy. Adjuvant radiotherapy only was given in 2 patients and 5 patients received chemotherapy without local radiotherapy and 10 patients received both modalities. The estimated 5-year overall survival and failure free survival rates for the entire group were 84.4% ± 7.2% and 63.8% ± 9.7% respectively, the 5-year OS and FFS were studied in correlation to age of patient, tumor size, different pathological types, site of the lesion and methods of local control. In patients with tumor size below 5 cm when compared to size more than 5 cm with OS was (100%) in comparison to (79.3 ± 9.3) who underwent complete surgical excision either initial or post chemotherapy as it was 66.7% versus 55.6% for those with gross or microscopic residual (p-value = .38). Also, the 3-year failure free survival was 75% versus 56.3% for those smaller than or equal 5 cm and those larger than 5 cmrespectively (p-value = .3).Conclusion: Increasing number of patients to increase sample size to assess tumor size and complete surgical excision as important prognostic factors as in our study, we found them statistically insignificant. Preoperative chemotherapy can help for delayed excision in patients presented initially with unresectable tumors

Stable Torque Optimization for Redundant Robots Using a Short Preview

We consider the known phenomenon of torque oscillations and motion instabilities that occur in redundant robots during the execution of sufficiently long Cartesian trajectories when the joint torque is instantaneously minimized. In the framework of on-line local redundancy resolution methods, we propose basic variations of the minimum torque scheme to address this issue. Either the joint torque norm is minimized over two successive discrete-time samples using a short preview window, or we minimize the norm of the difference with respect to a desired momentum-damping joint torque, or the two schemes are combined together. The resulting local control methods are all formulated as well-posed linear-quadratic problems, and their closed-form solutions also generate low joint velocities while addressing the primary torque optimization objectives. Stable and consistent behaviors are obtained along short or long Cartesian position trajectories, as illustrated with simulations on a 3R planar arm and with experiments on a 7R KUKA LWR robot.

Mitigation of DER-Caused Over-Voltage in MV Distribution Systems Using Voltage Regulators

This paper presents an investigation on the performance of voltage regulators (VRs) in mitigating overvoltage problems caused by distributed energy resources (DERs) in medium-voltage (MV) distribution systems. The control method of VRs is found to be a crucial factor. Studies reveal that even advanced control modes of commercial VRs cannot be relied upon as effective solutions to manage every scenario. The main problems associated with local control methods are identified. A supplementary voltage control scheme is proposed to enhance the capability of VRs as a solution option. The proposed scheme addresses the problems due to local control methods with a minimal investment. The studies are accompanied by several simulations on IEEE 123 nodes system as well as an actual feeder facing such overvoltage problems. Merits of the proposed supplementary control scheme are also demonstrated through simulation results.