Traditional Operation Research Articles

Teleoperated forwarder with VR: impact of latency on operator log handling performance

ABSTRACT This study uses a full scale cut to length forwarder prototype to explore crane log handling during teleoperation (remote-control). Visual feedback is provided from stereo cameras into a VR headset. Details of the system are provided along with measurements on key properties. The system allows for an artificial latency (the delay between a command and the observed response) to be introduced. A setup to allow repeated crane operations is used to evaluate operator performance at different latencies and also to compare teleoperation with in-machine operation. The results indicate that teleoperation of crane log handling can achieve comparable performance to traditional in-machine operation. Notably, the performance is consistent even at transmission latencies that surpass those expected in 4 G internet connections. This suggests a potential for remotely operating forwarders from both on-site and potentially off-site locations. This research did not delve into actual forwarding work or the implications of wireless connection bandwidth or alternative technologies like Wi-Fi or 5 G. Future investigations should consider these factors, along with the requirement for enhanced camera systems to ensure holistic machine visibility and consequently, safe teleoperation.

A Development and Evaluation of a Vertical Yam-Pounding Machine

A vertical yam pounding machine having a similar operational principle to the traditional method of pounding was developed. The machine consists of a shaft, pulleys, V-belts, bearings, an electric motor, a vertical pounder, a gear train and a pounding bowl. White yam was used to carry out a performance evaluation of the developed machine compared to a commercial yam pounder QASA® (LBQ041A, made in China) yam pounding machine and pounded yam from the traditional method of using mortar and pestle. It was observed that the traditional pounding operation, the developed and the QASA® yam pounding machines gave 89.73, 96.24 and 98.25% of well-pounded yam excluding lumps. However, the QASA® yam pounding machine is limited to a maximum of 4 kg mass of boiled yam. The average throughputs of the traditional pounding operation, the developed and the QASA® yam pounding machines were 20.3, 39.46 and 47.34 kg/h, while pounding times were 18 min, 10 min, and 5 min respectively. The developed machine had comparable quality with similar sensory scores with regards to the taste, aroma, stretchability, and mouldability to the one from the traditional method. It also had a comparative long-life span, and overall acceptability score and was preferred over the pounded yam produced by QASA® pounding machine.

Research on Regulation Method of Variable-Air-Volume Air Conditioning System with “Personal Space”

In large public facilities, such as airport terminals or open-plan office spaces, the HVAC system typically consumes substantial amounts of energy. However, individuals often gather at specific areas while other zones are occupied by transient or occasional users. To minimize operational energy usage, this paper aims to reduce thermal comfort demands in non-targeted areas. This paper introduces a method for regulating the thermal environment around occupants exclusively in the variable-air-volume (VAV) air conditioning running mode. The investigation utilizes Airpak modeling and experimental verification techniques. Additionally, an analysis of temperature field and velocity field distributions within the room under the “personal space” operation mode is presented. The results suggest that adjusting the numbers of air vents, openings, airflow velocities, and air supply orientations can establish a comfortable thermal environment for inhabitants and reduce the overall ADPI value. The combined air supply mode leads to a 16.7% reduction in power usage compared to traditional full-space operation.

Including dynamic capacity impact in an improved model for optimal flood control operation in river-type reservoirs

Flood control operations in river-type reservoirs are significantly affected by both the dynamic reservoir capacity and flood propagation within the reservoir area. However, the traditional reservoir flood control optimal operation (RFCOO) model is usually based on the static capacity method, which may bring large errors in scheduling calculations for river-type reservoirs. To address this issue, an improved model, the reservoir dynamic capacity flood control optimal operation (RDCFCOO) model, that includes the influence of the dynamic reservoir capacity and flood propagation, was developed to improve the accuracy of flood regulation calculations in river-type reservoirs. This improved model includes a 1D unsteady flow simulation and a rederived objective function based on the maximum peak clipping criterion, and expresses the state transformation equations using the de Saint-Venant equations. Furthermore, a multi-core parallel DP (PDP) algorithm that incorporates reduction of state dimensionality (RSD) was developed to effectively derive optimal operation schemes. The improved model and algorithm developed herein were validated through an application to the Xiangjiaba Reservoir, China. The results show that: (1) By adding the item (qiw) to the objective function and substituting the de Saint-Venant equations for the water balance equation, the RDCFCOO model developed in this paper can account for the impact of dynamic capacity and flood propagation. As a result, it exhibits a more accurate and detailed flood control process that was closer to the actual conditions of river-type reservoirs compared to the RFCOO model; (2) By removing the invalid discrete state points from the search space and fully utilizing multi-core processors, the proposed PDP with RSD can significantly improve the computational efficiency of the DP in solving RDCFCOO problems. The improved model and algorithm can effectively improve the calculation accuracy of flood control optimal scheduling in river-type reservoirs and provide more information for decision-makers.

Thread plate posture analysis for screw rolling adjustment design

Abstract This research focuses on process design of the adjustment of movable thread plate and fixed thread plate in the screw rolling machine during production. By observing some key dimensions of the threaded screw, one can determine the movement amount and the rotation direction of the adjustment screw bars mechanism of the fixed thread plate that required for the specified size of this type of screw. One establishes a relationship from the adjustment of the screw bars mechanism to the fixed thread plate posture. It can be seen that the formed screw size deviations will lead the machine operator to adopt one of the proposed process to achieve the posture adjustment of the fixed thread plate. While the screw specification deviations do not conform to the standard ones, the operator just need to find out the error type of the formed screw and measures its specification to follow one of the proposed formulas, then the wrong thread plate posture can be modified to the correct posture under operator’s adjustment. The method addressed in this research can not only reduce the operational difficulty of screw thread rolling machine but also can reduce the trial-and-error processes in traditional operation methods.

Application of remote sensing navigation system in total knee arthroplasty

To explore clinical accuracy of remote sensing navigation alignment (RSNA) system in total knee arthroplasty (TKA) and its influence on postoperative clinical efficacy. From May 2021 to May 2022, 60 knee osteoarthritis (KOA) patients with Kellgren-Lawrence (K-L) grade Ⅲ to Ⅳ treated by unilateral primary TKA were selected and divided into RSNA group and traditional operation group according to treatment methods, and 30 patients in each group. There were 6 males and 24 females in RSNA group, aged from 55 to 86 years old with an average of (68.06±8.23) years old;body mass index (BMI) ranged from 22.15 to 34.58 kg·m-2 with an average of (28.20±3.01) kg·m-2;the courses of disease ranged from 2 to 60 months with an average of (18.80±14.80) months;13 patients with grade Ⅲ and 17 patients with grade Ⅳ according to K-L grading. In traditional operation group, there were 8 males and 22 females, aged from 57 to 85 years old with an average of (67.26±6.32) years old;BMI ranged from 23.94 to 34.55 kg·m-2 with an average of (27.49±2.32) kg·m-2;the courses of disease ranged from 3 to 60 months with an average of (21.30±16.44) months;14 patients with grade Ⅲ and 16 patients with grade Ⅳ according to K-L grading. Western Ontario and McMaster Universities (WOMAC) osteoarthritis index and Knee Society score(KSS) were used to evaluate functional recovery of patients. Hip-knee-ankle angle (HKAA), distal femoral valgus angle (FVA) and distal fermoral flexion angle (DFFA) were measured before operation. HKAA and HKAA deviation angle were measured at 1 week after operation, and defective rate of lower limb force line, femur prosthesis valgus angle (FPVA) and femoral prosthesis flexion angle (FPFA), respectively, were calculated. There were no serious complications such as vascular and nerve injury during operation, and wound healed at stage Ⅰ. Both groups were followed up for 6 months. There were no significant difference in WOMAC index, KSS, HKAA, FVA and DFFA between two groups before operation (P>0.05). The force line defect rate, HKAA, HKAA deviation angle, FPVA deviation angle and FPFA of RSNA group were 6.7%, (178.74±1.56) °, (1.25±1.56) °, (1.84±0.16) ° and (4.85±2.46) °, respectively;while in traditional operation group were 20%, (176.73±3.46) °, (3.27±3.46) °, (2.44±0.26) °, (6.60±1.86) °;the difference between two groups were statistically significant (P<0.05). There were no significant difference in WOMAC index and KSS between two groups at 3 and 6 months after operation (P>0.05). RSNA system could reduce defective rate of lower limb force line, FPVA deviation angle and FPFA after TKA, which is more accurate and easy to operate than traditional intramedullary localization surgery while ensuring postoperative efficacy.

Active friction-regulated inertia impact piezoelectric actuator

In inertia impact piezoelectric actuators, the phenomenon of high-frequency drive-induced back-stepping poses a significant limitation to their overall performance. The ultra-fast response time of the piezoelectric stack enables the resolution of this issue. This paper introduces an inertia impact piezoelectric actuator operating under a novel Dual-Stack Motion Mode (DCMM), diverging from the traditional operation in the Single-Stack Motion Mode (STMM) that involves a solitary piezoelectric stack (PES) for active friction control. A comprehensive description of the actuator's structure and its operational principles under DCMM is provided. By constructing and experimentally evaluating the actuator using a controlled variable approach, a comparative analysis of performance between DCMM and STMM across various scenarios including different inertial mass blocks, driving voltages, frequencies, and load conditions was conducted. The experimental results indicate that DCMM significantly enhances the actuator's output performance, achieving a maximum speed of 1142.79 μm/s and a stable single-step displacement of 0.5 μm. The actuator features a simple yet effective structure and driving mechanism, allowing for multiple driving modes through the assembly of different inertial masses, thereby providing a substantial competitive advantage in output performance. The feasibility of using DCMM to improve actuator performance is corroborated by both theoretical and experimental studies. The ultra-fast response of the piezoelectric stacks expands the operational bandwidth of the actuator, achieving a seamless integration of speed and precision.

NKDFF-CNN: A convolutional neural network with narrow kernel and dual-view feature fusion for multitype gesture recognition based on sEMG

Deep learning algorithms have been widely applied to gesture recognition based on multi-channel surface electromyography (sEMG). However, the limitations in feature extraction capabilities of existing algorithms have restricted the performance of multitype gesture recognition. To address this challenge, we propose a novel sEMG-based gesture recognition algorithm, namely, Narrow Kernel and Dual-view Feature Fusion Convolutional Neural Network (NKDFF-CNN). Firstly, to overcome the issue of traditional square kernel convolution operation, which loses channel independence features, we employ the narrow kernel convolution in the model to learn time-related features in each independent channel of sEMG, resulting in obtaining representative correlation information between specific muscles and gestures. Then, the dual-view structure is used to capture both shallow and deep features, which are fused at the decision level. Thus, the multi-dimensional feature information is extracted. The NKDFF-CNN is further extended to ACCNKDFF-CNN by introducing acceleration signals for multimodal feature integration. Experimental validation on the NinaPro DB2 dataset demonstrates the superior classification performance of NKDFF-CNN, achieving 88.03 % accuracy for 49 hand gestures, outperforming other state-of-the-art MSFF-net. In addition, the ACCNKDFF-CNN model with multimodal feature information significantly improved the accuracy to 95.25 %. We also validated the proposed NKDFF-CNN on NinaPro DB3 with the disabled subjects and the NinaPro DB4 with healthy subjects. The results showcased that the NKDFF-CNN achieved advanced accuracies of 70.58 % and 85.91 % for the multitype hand gestures classification, respectively, showing the high generalization ability of the proposed model. As a consequence, the proposed NKDFF-CNN method achieved superior recognition performance in both accuracy and generality compared to other advanced models. Thus, it provides a reliable algorithm for research in fields such as rehabilitative medicine.

Treatment of thoracolumbar tuberculosis with robot-assisted and minimally invasive access via transforaminal expansion approach

To investigate the feasibility and effectiveness of robot-assisted posterior minimally invasive access in treatment of thoracolumbar tuberculosis via transforaminal expansion approach. A clinical data of 40 patients with thoracolumbar tuberculosis admitted between January 2017 and May 2022 and met the selection criteria was retrospectively analyzed. Among them, 15 cases were treated with robot-assisted and minimally invasive access via transforaminal expansion approach for lesion removal, bone graft, and internal fixation (robotic group), and 25 cases were treated with traditional transforaminal posterior approach for lesion removal and intervertebral bone grafting (traditional group). There was no significant difference in the baseline data between the two groups ( P>0.05) in terms of gender, age, lesion segment, and preoperative American Spinal Injury Association (ASIA) grading, Cobb angle, visual analogue scale (VAS) score, erythrocyte sedimentation rate (ESR), and C reactive protein (CRP). The outcome indicators were recorded and compared between the two groups, including operation time, intraoperative bleeding volume, hospital stay, postoperative bedtime, complications, ESR and CRP before operation and at 1 week after operation, the level of serum albumin at 3 days after operation, VAS score and ASIA grading of neurological function before operation and at 6 months after operation, the implant fusion, fusion time, Cobb angle of the lesion, and the loss of Cobb angle observed by X-ray films and CT. The differences of ESR, CRP, and VAS score (change values) between pre- and post-operation were calculated and compared. Compared with the traditional group, the operation time and intraoperative bleeding volume in the robotic group were significantly lower and the serum albumin level at 3 days after operation was significantly higher ( P<0.05); the postoperative bedtime and the length of hospital stay were also shorter, but the difference was not significant ( P>0.05). There were 2 cases of poor incision healing in the traditional group, but no complication occurred in the robotic group, and the difference in the incidence of complication between the two groups was not significant ( P>0.05). There were significant differences in the change values of ESR and CRP between the two groups ( P<0.05). All Patients were followed up, and the follow-up time was 12-18 months (mean, 13.0 months) in the traditional group and 12-16 months (mean, 13.0 months) in the robotic group. Imaging review showed that all bone grafts fused, and the difference in fusion time between the two groups was not significant ( P>0.05). The difference in Cobb angle between the pre- and post-operation in the two groups was significant ( P<0.05); and the Cobb angle loss was significant more in the traditional group than in the robotic group ( P<0.05). The VAS scores of the two groups significantly decreased at 6 months after operation when compared with those before operation ( P<0.05); the difference in the change values of VAS scores between the two groups was not significant ( P>0.05). There was no occurrence or aggravation of spinal cord neurological impairment in the two groups after operation. There was a significant difference in ASIA grading between the two groups at 6 months after operation compared to that before operation ( P<0.05), while there was no significant difference between the two groups ( P>0.05). Compared with traditional posterior open operation, the use of robot-assisted minimally invasive access via transforaminal approach for lesion removal and bone grafting internal fixation in the treatment of thoracolumbar tuberculosis can reduce the operation time and intraoperative bleeding, minimizes surgical trauma, and obtain definite effectiveness.

Analysis of Accounting Teaching Reform in Colleges and Universities from the Perspective of Blockchain

With the rapid development of information technology, blockchain technology, as an innovative distributed ledger technology, has begun to be applied in many fields such as finance, supply chain management, and the Internet of Things. As an important part of economic management, accounting faces the challenge of transforming from traditional manual operation to intelligent and automated direction. The characteristics of blockchain technology, such as decentralization, data immutability and transparency, provide new solutions for the authenticity, accuracy and completeness of accounting information. Based on this, this paper mainly discusses and analyzes how to reform accounting teaching in colleges and universities through blockchain.

Optimal distributed energy scheduling for port microgrid system considering the coupling of renewable energy and demand

The increased uptake of distributed renewable energy in port areas is facilitating the electrification and net zero transition of marine ports. Effective operation that considers unique characteristics of the port is critical to minimize the operating cost in the port microgrid (PMG). In this paper, we propose a joint scheduling method that considers the impact of tidal patterns on the period and intensity of port operations. The method takes advantage of the strong correlations between renewable energy (solar, wind and tidal) and multi-class load to support the PMG operator in determining the most cost-effective scheduling of energy supply and flexible loads during port activities. Additionally, the traditional centralized operation is vulnerable to local failures, and distributed operation for hundreds of energy units will result in significant computational burden, neither of which is suitable for the PMG operation. Our work decouples the PMG system based on the port functions and thus decomposes the PMG operation into a few subproblems. Then, we hierarchically solve the primal and dual problems by a distributed algorithm. Simulation results illustrate the benefits of tidal energy in the renewable generation mix. Furthermore, the proposed method achieves cost reductions of 12.4% and 21.7% under two different tidal patterns.

The Loop Technique in Cardiac Resynchronization Therapy: A Prospective Cohort Study.

A new approach called the loop technique has been proven safe and effective for repeated intraoperative transvenous left ventricular (LV) lead dislocations during cardiac resynchronization therapy (CRT) in a 3-year follow-up. This study aimed to report on the 5-year safety and effectiveness of the loop technique. This study was a prospective cohort study. Forty-four patients who underwent CRT device implantation at the Cardiology Department of Shaanxi Provincial People's Hospital between January 2013 and June 2019 were included. Data on patient demographics, medical history, laboratory test results, and echocardiography images at admission were collected. The loop technique was performed with repeated intraoperative dislocations of the LV lead. The intraoperative CRT parameters were also recorded. All patients were followed for 5 years. Several auxiliary examinations were performed during follow-up. The 44 patients were divided into the traditional operation group (n=36, 81.8%) and loop technique group (n=8, 18.2%). The baseline patient characteristics were almost balanced. During the 5-year follow-up, 8 (22.2%) patients in the traditional operation group and 2 (25.0%) patients in the loop technique group died. No lead dislocation or other complications related to CRT were observed. There were no significant differences in mortality rate (P=0.87), cardiac function (P=0.56), echocardiographic indices, threshold (P=0.58), or impedance (P=0.22) of the LV lead. There were no significant differences in the threshold and impedance between postoperative, 3-year, and 5-year follow-ups in the loop technique group (P=0.53). The loop technique is an ideal solution for repeated intraoperative LV lead dislocation during CRT implantation.

Surgical Correction of Orbital Hypertelorism With Absorbable Plate Instead of Frontal and Orbital Bar and Inverted U-Shaped Osteotomy.

The aim of the study is to investigate the effect and feasibility of using absorbable plate instead of frontal and orbital bar and inverted U-shaped osteotomy to correct the widening of orbital distance. The surgical effect and feasibility of using absorbable plate instead of frontal and orbital bridge plus inverted U-osteotomy for orbital widening syndrome in seven cases between January 2019 and February 2022 were retrospectively analyzed. First, the surgical procedure for orbital hypertelorism was inverted U-shaped orbital osteotomy, and a frontal bone flap was removed, exposing the superior orbital margin and the orbital circumference, and the orbital bone was directly cut off by inverted U-shaped osteotomy. The widened bone in the middle of the orbit was removed, and a long absorbable plate was used to replace the orbitofrontal bridge. The two sides of the orbit were fixed on the absorbable plate, and the absorbable plate was fixed on the rear skull. The clinical effect of treatment, complications (such as cerebrospinal fluid leakage and infection), safety, and feasibility of surgery were evaluated. Using absorbable plate instead of fronto-orbital bridge achieved the effect of orbitofrontal bridge, without orbital distance widening, cerebrospinal fluid leakage, and intracranial infection. Operating time was reduced. There was no metal fixation, and there was no risk of a second operation. The effect of replacing the frontal-orbital bridge with an absorbable plate and inverted U-shaped osteotomy is positive, the operation time is short, and the orbital distance is clearly improved. This approach can replace the traditional orbital-distance operation, and the incidence of postoperative cerebrospinal fluid leakage and infection is low. Long-term follow-up results are stable.

Urethral Mobilisation and Glanuloplasty Technique for Primary and Second-Stage Repair of Hypospadias: A Single Hospital Experience.

Background Over the years, the technique used to correct hypospadias has undergone several modifications to improve outcomes and reduce complication rates. In this study, a modification has been made to the second stage of the two-stage repair of proximal hypospadias. This modification utilises urethral mobilisation and glanuloplasty, traditionally used to repair distal hypospadias, in the second stage of repair of proximal hypospadias. This study aims to assess the implications of this modification on the outcomes in addition to adding to the pre-existing literature on the outcomes of urethral mobilisation and glanuloplasty in the repair of distal hypospadias. Methodology A prospective study was conducted at Salmaniya Medical Complex in Bahrain between January 2016 and December 2021. All patients with either proximal or distal hypospadias who underwent a surgical repair using the urethral mobilisation and glanuloplasty technique were included. The following cases were excluded: patients with proximal hypospadias who did not undergo a first-stage repair, those with a hypoplastic urethra, and those aged 14 years or more. Results The mean operative time for the proximal hypospadias group was 78 minutes, while it was 62 minutes in the distal hypospadias group. Furthermore, the catheter remained in situ for a mean of three days postoperatively in the proximal hypospadias group. Overall, four of 35 patients (11.4%) experienced complications in the proximal hypospadias group. Of these, there were two(5.7%) cases of meatal stenosis, two(5.7%) cases of wound dehiscence, and no cases of diverticula or urethrocutaneous fistulas. Meanwhile, in the distal hypospadias group, one of 117 patients (0.9%) experienced a complication; the complication was meatal stenosis. there was a significant correlation between the age of patients and the complication rate (p = 0.06). The operative time was also found to be a significant factor influencing the occurrence of complications. The follow-up duration ranged between five months and 12 months. All patients had good cosmetic outcomes. Conclusions This study found that urethral mobilisation and glanuloplasty for the second-stage repair of proximal hypospadias resulted in lower complications than the traditional two-stage operation and a short duration of urinary catheterisation. There is a need to conduct studies with longer follow-up durations and objective measures of function to provide a better comparison between the different techniques used.

Distributed Cooperative Optimal Operation of Multiple Virtual Power Plants Based on Multi-Stage Robust Optimization

This paper develops a distributed cooperative optimization model for multiple virtual power plant (VPP) operations based on multi-stage robust optimization and proposes a distributed solution methodology based on the combination of the alternating direction method of multipliers (ADMMs) and column-and-constraint generation (CCG) algorithm to solve the corresponding optimization problem. Firstly, considering the peer-to-peer (P2P) electricity transactions among multiple VPPs, a deterministic cooperative optimal operation model of multiple VPPs based on Nash bargaining is constructed. Secondly, considering the uncertainties of photovoltaic generation and load demand, as well as the non-anticipativity of real-time scheduling of VPPs in engineering, a cooperative optimal operation model of multiple VPPs based on multi-stage robust optimization is then constructed. Thirdly, the constructed model is solved using a distributed solution methodology based on the combination of the ADMM and CCG algorithms. Finally, a case study is solved. The case study results show that the proposed method can realize the optimal scheduling of renewable energy in a more extensive range, which contributes to the promotion of the local consumption of renewable energy and the improvement of the renewable energy utilization efficiency of VPPs. Compared with the traditional deterministic cooperative optimal operation method of multiple VPPs, the proposed method is more resistant to the risk of the uncertainties of renewable energy and load demand and conforms to the non-anticipativity of real-time scheduling of VPPs in engineering. In summary, the presented works strike a balance between the operational robustness and operational economy of VPPs. In addition, under the presented works, there is no need for each VPP to divulge personal private data such as photovoltaic generation and load demand to other VPPs, so the security privacy protection of each VPP can be achieved.

Numerical Simulation Research on Combustion and Emission Characteristics of Diesel/Ammonia Dual-Fuel Low-Speed Marine Engine

Amid increasingly stringent global environmental regulations, marine engines are undergoing an essential transition from conventional fossil fuels to alternative fuels to meet escalating regulatory requirements. This study evaluates the effects of injection pressure, the timing of ammonia injection, and the pre-injection of ammonia on combustion and emissions, aiming to identify optimal operational parameters for low-speed marine engines. A three-dimensional model of a large-bore, low-speed marine engine in a high-pressure diffusion mode was developed based on computational fluid dynamics (CFD). Simulations were conducted under 25%, 50%, 75% and 100% loads with a high ammonia energy substitution rate of 95%. The results indicate that, compared to traditional pure diesel operation, adjusting the injection pressure and the ammonia injection timing, along with employing appropriate pre-injection strategies, significantly enhances in-cylinder pressure and temperature, improves thermal efficiency, and reduces specific fuel consumption. Additionally, the dual-fuel strategy using diesel and ammonia effectively reduces nitrogen oxide emissions by up to 37.5% and carbon dioxide emissions by 93.7%.

An integrated approach of timetable and train ratio optimisation based on event-driven model with express/local mode

Express/local mode is an innovation combined with both express train and local train in metro system, which can offer conventional service for every station and rapid service for selected stations. The traditional operation planning for express/local mode is often carried out sequentially, leading to sub-optimality in the overall scheme and even an inability to match passenger demand. This paper aims to propose an integrated optimization approach of timetable and train ratio in express/local mode. An event-driven model and a ratio decomposition method are introduced to facilitate modeling of the problem. Then, a Two-stage Active Set Method is designed to solve the proposed model. The approach is verified through an example from Guangzhou Metro Line 14, revealing the correlation between train ratio and passenger waiting time. The results indicate that the approach can effectively allocate capacity resources of trains, leading to a significant 19.2% reduction in passenger waiting time.

Investigation on optimization strategy of IoT operation mode based on blockchain

Under the call of the national scientific and technological power, the research in the field of sensor technology has made rapid progress. Many smart devices integrating various technical heights have entered the homes of ordinary people. Making these smart devices increasingly intelligent has greatly improved people’s lifestyles and even changed their lives. With the development of blockchain technology and the development of 5G communication equipment and applications, the industrial model of Blockchain and the Internet of Things can also become an important guide for the development of the Internet of Things. Therefore, this paper studies the optimization strategy of the IoT operation mode based on Blockchain. The research results have shown that the IoT operation mode based on Blockchain is superior to the traditional IoT operation mode in terms of node energy consumption, life cycle, and flux performance. Under the IoT operation mode of the Blockchain, the node energy consumption is reduced by about 1.19J on average, and the flux performance is increased by about 21 on average. This showed that the IoT operation model based on Blockchain is feasible.

Novel positioning guiders accurately assist in situ acetabular reconstruction for patients undergoing pelvic bone tumor resection.

Acetabular reconstruction in situ after extensive pelvic resection is technically challenging. The aim of this study was to investigate the feasibility of positioning guiders for acetabular reconstruction following pelvic tumor resection and the clinical benefit brought by the approach. The study included patients who underwent acetabular reconstruction following periacetabular tumor resection using a modular hemipelvic prosthesis. In the guider-assisted group (n = 14), guiders were designed and applied to assist acetabular reconstruction. In the traditional operation group (n = 18), the patients underwent the same surgery but without the guiders. The displacement of the hip rotation center before and after surgery was calculated. The complications and the Musculoskeletal Tumor Society-93 scores were documented. The overall displacement of the hip rotation center was significantly reduced in the guider-assisted group compared with the traditional operation group (13.83 ± 4.06 vs. 22.95 ± 9.18mm in P = 0.000, 95%CI 3.90-12.96), especially in the anteroposterior axis (3.77 ± 3.03 versus 13.51 ± 9.43mm in P = 0.000, 95%CI 3.45-13.09). Guider-assisted acetabular reconstruction reduced the risk of prosthesis dislocation compared with the traditional operation (dislocation risks: 1/14, 7.1% vs. 4/18, 22.2%). Positioning guiders can effectively and conveniently help place the modular hemipelvic prosthesis at the native position, which might potentially reduce the risk of prosthesis dislocation. Therapeutic level III.

Aggregated model of an active distribution system for coordinated TSO–DSO fast frequency control

The growing integration of distributed energy sources (DERs) challenges the traditional independent operation of transmission system operators (TSOs) and distribution system operators (DSOs). The coordination between TSOs and DSOs becomes essential, as DERs not only offer local ancillary services but also enable the provision of these services at the distribution network level following disturbances in the transmission system. To enhance power system analyses in TSO–DSO coordination, the availability of reduced-order or aggregated models proves crucial, avoiding detailed modeling and reducing computational burden. Addressing the lack of reduced-order models capturing the dynamics of diverse distributed technologies and their control systems within a unified single-device model, this paper introduces a single equivalent device based on virtual synchronous machine (VSM) technology. This device effectively subsumes the frequency response of various DERs and loads. The proposed aggregation methodology undergoes validation on systems of different sizes and compositions of DERs. Results from simulated scenarios consistently demonstrate the accuracy and generalizability of the proposed aggregated model, irrespective of system size and included technologies.