Beginner Operators Research Articles

Optical microscopy evaluation of root canal filling removal by beginner operators in posterior teeth.

This study analyzed the effectiveness of root canal filling removal in lower molars performed by beginner operators using optical microscopy. A total of 55 mandibular first and second molars with mesial roots exhibiting an average curvature of 10-20° were selected based on preoperative radiographs. Instrumentation was done with ProTaper Gold (Dentsply Sirona) up to F2 (25/.08), using 2ml of 2.5% NaOCl irrigation solution after each file. Root canal obturation was performed using gutta-percha points with cold lateral condensation and Sealapex (Kerr Dental). Coronal fillings were made with composite resin and stored in distilled water for two years. Removal of the root canal fillings was performed with AF Retreatment Rotary (AFRR) and AF Blue R3 (AFBR3) (Fanta Dental Materials) under reciprocating motion with 2.5% NaOCl irrigation. Cross-sections of the coronal, middle, and apical thirds were analyzed at 40x magnification using a STEINDORFF POL microscope with a digital camera. Image analysis was conducted using Image J software, version 1.54, to determine the efficiency of root canal filling removal by percentage. Statistical analysis via one-way ANOVA revealed significant differences between distal and mesial roots (P < 0.05). Specifically, for mesial roots, the removal efficiency was 70.65% in the coronal third, 54.66% in the middle third, and 21.32% in the apical third. Significant difficulties were noted due to fractured files, calcifications, and debris accumulation in the isthmuses. The study concluded that the protocol using Fanta files demonstrated significant differences in removal efficiency correlated with root curvature, compounded by the inexperience of beginner operators. The findings highlight the challenges faced by novice practitioners in achieving effective root canal filling removal.

Calculation of Kidney Volumes with Magnetic Resonance in Patients with Autosomal Dominant Polycystic Kidney Disease: Comparison between Methods

Autosomal dominant polycystic renal disease (ADPKD) is the most frequent kidney inheritable disease, characterized by the presence of numerous bilateral renal cysts, causing a progressive increase in total kidney volume (TKV) and a progressive loss of renal function. Several methods can be used to measure TKV by using MRI, and they differ in complexity, accuracy and time consumption. This study was performed to assess the performance of the ellipsoid method and the semi-automatic segmentation method, both for TKV and SKV (single kidney volume) computation. In total, 40 patients were enrolled, and 78 polycystic kidneys analyzed. Two independent operators with different levels of experience evaluated renal volumetry using both methods. Mean error for ellipsoid method for SKV computation was −2.74 ± 11.79% and 3.25 ± 10.02% for the expert and the beginner operator, respectively (p = 0.0008). A Wilcoxon test showed a statistically significant difference between the two operators for both methods (SKV p = 0.0371 and 0.0034; TKV p = 0.0416 and 0.0171 for the expert and the beginner operator, respectively). No inter-operator significant difference was found for the semi-automatic method, in contrast to the ellipsoid method. Both with a Wilcoxon test and Bland–Altman plot, statistically significant differences were found when comparing SKV and TKV measurements obtained with the two methods for both operators, even if the differences are stronger for the beginner operator than for the expert one. The semi-automatic segmentation method showed more inter-observer reproducibility. The ellipsoid method, in contrast, appears to be affected by greater inter-observer variability, especially when performed by operators with limited experience.

Evaluation of the operator learning curve for radiofrequency ablation for atrioventricular nodal reentrant tachycardia

Aim The aim of this study was to determine the average minimum number of slow pathway ablation procedures required to reach a steady success rate among inexperienced operators.Material and Methods We analyzed the consecutive AVNRT ablation procedures of three inexperienced operators for the rate of operational success and complications.Results Operators performed a total of 156 AVNRT ablation procedures. There was no statistical significance between the three operators regarding the rate of success (p=0.69) and complications. There were significant differences between the operators in terms of procedure time, fluoroscopy time, and cumulative air kerma. The variability of procedure time and cumulative air kerma, both among three operators and within each operator, decreased significantly after the 25th case. Each operator was analyzed individually for the probability of success as related to the cumulative number of ablations. All trainee operators reached a success rate of 90 % at the 27th procedure.Conclusion An average of 27 slow pathway ablation procedures should be performed by a beginner operator to achieve proficiency.

Comparison of axial and coronal axis MRI kidney volume measurement in pediatric congenital solitary kidney.

Accurate estimation of kidney size and volume in the solitary functioning kidney is crucial because of a higher risk of developing kidney injury. MRI is an accurate method and is suitable for kidney volume measurement. Usually, axial axis images and measurement methods are preferred for kidney volume measurements. However, the anteroposterior diameter of the kidney is smaller than the longitudinal diameter, meaning that imaging in the coronal axis could provide needed information in a shorter time, enabling imaging of younger patients without sedation. Therefore, the purpose of this study was to compare coronal and axial axis kidney volume measurement methods and evaluate intra-observer and inter-observer reliability. Axial axis T2W and coronal axis FIESTA images of kidneys were obtained with 10mm slice thickness and no slice gap in pediatric patients with congenital solitary kidneys. Free-hand manual tracing was used to calculate volumes in both methods. Images were analyzed by two operators with different levels of experience. The expert operator computed solitary kidney volume twice in both methods for the intra-observer reliability, while the beginner operator's measurements were used for the inter-observer reliability. High intra-observer (0.965 for axial and 0.972 for coronal) and inter-observer reliability were revealed (0.964 for axial and 0.963 for the coronal) for both measurement methods. The coronal plane volume measurement method, which has a significantly shorter examination and post-processing time, is a highly reproducible and reliable method that can enable volume measurement with MRI in younger children, as the imaging time will be shortened. A higher resolution version of the Graphical abstract is available as Supplementary information.

Improvement of diagnostic efficiency in fetal congenital heart disease using fetal intelligent navigation echocardiography by less-experienced operators.

This study investigated the feasibility and accuracy of fetal intelligent navigation echocardiography (FINE) for the prenatal diagnosis of congenital heart disease (CHD) by inexperienced and experienced operators. In this prospective study, all volume data sets from 120 fetuses with a broad spectrum of CHD were acquired using spatiotemporal image correlation technology. The prenatal diagnostic procedures were performed by two operators with different experience (beginner: 1year and expert: 15 years) using FINE and traditional fetal echocardiography. Data were analyzed on the time of examination and acquisition of results. Diagnoses made by FINE and traditional echocardiography were completely consistent with the final diagnosis of CHD in 98 (81.66%) versus 20 (16.66%) (P< 0.001) beginners and 87.50% (n= 105) versus 101 (84.16%) experts, respectively. On the contrary, there was significant difference using traditional echocardiography (16.66% versus 84.16%, P< 0.001) by two examiners. Furthermore, the examination time decreased when using FINE compared with using traditional echocardiography (beginner operators: 4.54 ± 1.03 min versus 20.58 ± 3.36 min, P< 0.001; expert operators: 3.89 ± 0.96 min versus 12.73 ± 1.62 min, P< 0.001). Based on our results, a prenatal diagnosis of CHD can be made with high feasibility and accuracy using FINE compared with traditional fetal echocardiography for beginner operators.

The challenge of education in conduction system pacing: results from single or dual operators

Abstract Background The his bundle pacing (HBP) and Left bundle branch pacing (LBBp) techniques are quickly increasing in the cardiovascular interest being the most physiological mode of pacing. Education in these new conduction system pacing (CSP) is mandatory in the modern EP programs. Achieving acceptable implant success rate, together with electrical parameters adequacy is required. Objective The aim of the study was to compare clinical and technical outcomes in 2 groups of patients, those implanted by a single operator with large expertise in CSP and those implanted by two operators (one of them during his learning curve). Methods Data from 255 consecutive patients (mean age 78±9 years; 186 males) who underwent successful HBP or LBBp implants were collected and analyzed. The operators were classified as expert after performing more than 50 procedures. Baseline caracteristics were not significantly different between the two groups. Results After a mean follow-up of 20±10months, we found that there were no differences between patients implanted by 1 single expert operator and 2 operators (1 beginner during his learning cirve supervised by 1 expert operator) in terms of clinical end point (composite of death or heart failure hospitalizations) and technical end point (need for surgical revision of the implant for reason other than battery replacement). Fluoroscopy time (16±17 min vs 9.8±11 min; p 0.004) and procedural time (113±48 min vs 16±17 min; p 0.003) were significantly prolonged when the implant was performed by 2 operators. Conclusions Skill acquisition in physiological pacing (both HBP and LBBp) is a nowadays process which cannot put patient's safety at risk. Our experience shows that clinical and technical outcomes were equivalent when the implant was performed by an expert operator or a beginner operator supervised by 1 expert operator. Fluoroscopy time and duration of the procedure were significantly prolonged by the presence of a trainees. Kaplan Meyer curves Funding Acknowledgement Type of funding source: None

Fuzzy logic-based decision-making system design for safe forklift truck speed: cast cobblestone production application

This paper presents a model in which “fuzzy logic multi-criteria decision-making method” is suggested to determine real-time forklift speed to reduce occupational accidents caused by operators. The model developed in the study uses the variables: the weight and height of the load carried by the forklift, the number of products on its pallet, the places with high risk of accident, and the wet-dry condition of the ground. In order to evaluate the performance of the suggested model, a data set comprises 128 different conditions in cast cobblestone production. Determined forklift speeds were compared with the forklift speeds determined by fuzzy logic using statistically analyses. Results showed that fuzzy logic model has a high accuracy and low error. Fuzzy logic modeling has proved to be a good way to decide the real-time speed of the forklifts being used in production without compromising occupational safety. Friedman test and Wilcoxon test have been used to estimate the significance of fuzzy logic method. The fuzzy logic results showed that our method achieved better results compared to beginner operator.

Performance Evaluation on Rotary Preparation of Root Canal by Beginner Operators.

This study aims to analyze the performance of rotary root canal preparation, conducted by beginner operators (students). After acquiring the necessary skills involved in applying endodontic preparation techniques on extracted teeth, all students from a cohort learned to use ProTaper Universal files (Dentsply Maillefer). The preclinical training had several stages. Experience 1: instrumentation on extracted single-root teeth; Experience 2: instrumentation on EndoTraining blocks (Dentsply Maillefer); Experience 3: instrumentation on EndoTraining blocks (Dia Dent Group International); Experience 4: Instrumentation on extracted multiradicular teeth. Preparation was done according to the manufacturer’s instructions, the initial file is Sx, followed by S1, S2, F1, F2 and the last file is F3. A batch of 50 teeth (E1, E2, E3, E4) was randomly selected to evaluate the onset of the rotary preparation of young operators. Two independent evaluators analyzed the array radiologically by stereomicroscope evaluation (E1, E4) and photo-analysis of the resulting Endo Training blocks (E2, E3). The success rate was 80% for E1, 72% for E2, 64% for E3 and 76% for E4 (p<0.05). The following were considered a failure: ledge formation and apical transportation in 10.66%, over instrumentation in 6.66%, zipping in 3.33%, and instrument fracture in 4% of cases.Endodontic instrumentation techniques require training to acquire the necessary skills. Rotary root canal instrumentation techniques used almost exclusively in modern endodontics require adequate preclinical training.

Optimizing HR-pQCT workflow: a comparison of bias and precision error for quantitative bone analysis.

High-resolution peripheral quantitative computed tomography workflow includes manually correcting contours generated by the manufacturer's automated protocol. There is interest in minimizing corrections to save time and reduce precision error; however, bias related to the automated protocol is unknown. This study quantifies error bias when contours are uncorrected and identifies the impact of operator training on bias and precision error. Forty-five radii and tibiae scans across a representative range of bone density were analyzed using the automated and manually corrected contours of three operators, with training ranging from beginner to expert, and compared with a "ground truth" to estimate bias. Inter-operator precision was measured across operators. The tibia had greater error bias than the radius when contours were uncorrected, with compartmental bone mineral densities and cortical microarchitecture having greatest biases, which could have significant implications for interpretation of studies using this skeletal site. Bias and precision error were greatest when contours were corrected by the beginner operator; however, when this operator was removed, bias was no longer present and inter-operator precision was between 0.01 and 3.74% for all parameters except cortical porosity. These findings establish the need for manual correction and provide guidance on operator training needed to maximize workflow efficiency.

Skills development of mechanized softwood sawtimber cut-to-length harvester operators on the Highveld of South Africa

ABSTRACTIn this study, a South African pine sawtimber mechanized cut-to-length harvesting operation was analyzed with the objective of modelling productivity development learning curves of beginner operators in both clear-felling and thinning operations. Trainee operators were selected based on the results of an assortment of psychometric testing and subsequently completed several harvester simulator tests. On average, a trainee operator would start at aperformance level (PL) of 60% lower than the population’s mean test time per test (PTmean) and end with a PL of 22% higher than the PTmean. Furthermore, when the PL of an average simulator trainee was measured over a period of 8.4 days or 25.2 tests (three tests per day), the operator’s PL was improved by 200%. Following sufficient simulator training, the operators began working in-field. Thinning operators worked with an average tree size of 0.18 m3, starting at a productivity of 13.71 m3 per productive machine hour excluding delays longer than 5 minutes (PMH5) at month one and increasing their productivity to 38.96 m3·PMH5−1 by the end of month 12. Clear-felling operators worked with an average tree size of 0.54 m3, starting at a productivity of 27.56 m3·PMH5−1 at month one and increased their productivity to 43.75 m3·PMH5−1 by the end of month 12. Ultimately, the thinning and clear-fell operators reached the end of their learning curves after an average of 9 and 6.5 months, and increased their productivity performances by 218% and 104%, respectively. These findings suggest acceptable learning periods and performance increases for beginner harvester operators.

Learning curves of two different techniques for the intra-articular injection of the knee joint under fluoroscopic guidance

The aim of the study was to compare the learning curves of three beginner operators using two different techniques of intra-articular injection of the knee under fluoroscopic guidance with a superolateral approach. In total, 177 consecutive patients (72 females (40.7%) and 105 males (59.3%), mean age 42.2±15.0years) scheduled for a computed tomography (CT) arthrography and without joint effusion on the lateral X-rays were enrolled. They underwent an intra-articular injection of the knee under fluoroscopic guidance with a superolateral approach. Patients were randomly assigned to three different operators, including a junior supervisor and two first-year residents in radiology who never performed an intra-articular injection of the knee before the present study. Procedures in lateral or supine position were randomly assigned tothree operators. There was a higher rate of successful injections with the lateral position (92.1%) than with supine position (80.2%) (odds ratio (OR) 4.52, 95% confidence interval (CI) 1.46-14.0). A significant learning effect was observed for the supine position, while none was observed for the lateral position. Pain and time of fluoroscopy did not differ between the two procedures (p=0.85 and p=0.10, respectively). Junior supervisor had a higher rate of successful intra-articular injection compared with the other two operators (p=0.0072). There was a statistically significant higher rate of extravasation with the supine position (66.3%) than with lateral position (19.7%) (p<0.0001, OR 0.13, 95% CI 0.06-0.25). The intra-articular injection of the knee under fluoroscopic guidance with the patient in lateral position is an easy technique for operators in training with a low rate of extravasation. Lateral position does not require a supplementary irradiation and does not increase the procedural pain. Personal operator's skill is an independent factor in determining the success of the training.

Is Contrast Enhanced Ultrasonography a useful tool in a beginner's hand? How much can a Computer Assisted Diagnosis prototype help in characterizing the malignancy of focal liver lesions?

Contrast enhanced ultrasound (CEUS) improved the characterization of focal liver lesions (FLLs), but is an operatordependentmethod. The goal of this paper was to test a computer assisted diagnosis (CAD) prototype and to see its benefitin assisting a beginner in the evaluation of FLLs. Our cohort included 97 good quality CEUS videos[34% hepatocellular carcinomas (HCC), 12.3% hypervascular metastases (HiperM), 11.3% hypovascular metastases (HipoM),24.7% hemangiomas (HMG), 17.5% focal nodular hyperplasia (FNH)] that were used to develop a CAD prototype based onan algorithm that tested a binary decision based classifier. Two young medical doctors (1 year CEUS experience), two expertsand the CAD prototype, reevaluated 50 FLLs CEUS videos (diagnosis of benign vs. malignant) first blinded to clinical data,in order to evaluate the diagnostic gap beginner vs. expert. The CAD classifier managed a 75.2% overall (benign vs.malignant) correct classification rate. The overall classification rates for the evaluators, before and after clinical data were:first beginner-78%; 94%; second beginner-82%; 96%; first expert-94%; 100%; second expert-96%; 98%. For both beginners,the malignant vs. benign diagnosis significantly improved after knowing the clinical data (p=0.005; p=0,008). The expert wasbetter than the beginner (p=0.04) and better than the CAD (p=0.001). CAD in addition to the beginner can reach the expertdiagnosis. The most frequent lesions misdiagnosed at CEUS were FNH and HCC. The CAD prototype is a goodcomparing tool for a beginner operator that can be developed to assist the diagnosis. In order to increase the classification rate,the CAD system for FLL in CEUS must integrate the clinical data.

2A1-S04 2自由度制御による天井クレーンの制振搬送(人間機械協調)

This paper deals with the sway control of the overhead crane using 2-DOF control. High operation skill is necessary in the transport with reduced vibration of the payload. However, a skilled operator has been reduced. For this reason, the operation support system that can be easily operated even a beginner is required. Many researchers report that are to be achieved the transport with reduced vibration using a feedforward control or a feedback control. Only a feedforward control can't be achieved the transport with reduced vibration in any operation, and only a feedback control can't be achieved an improvement in operability. Therefore, we use 2-DOF control to design the controller to achieve the transport with reduce vibration and improve operability. The experimental results show the transport with reduced vibration even if the beginner operator is operated.

Using of DEVS and MAS Tools for Modeling and Simulation of an Industrial Steam Generator

Complex systems are made of many elementary components in interaction. To model such systems, it is generally more convenient to decompose them into subsystems that are simpler to handle. This new division is to be made in a methodical way, by identification and complete definition of the various structures, actions and interactions of those sub-systems. In this work, the decomposition of the overall system into sub-systems is based primarily on the use of the Discrete EVent System Specification (DEVS) formalism. The obtained atomic and coupled models are formally verified and validated. Then, we use the Multi-agent Development KIT (MAD-KIT) Multi Agent Systems (MAS) operational tools to implement an industrial simulator. This simulator is used by beginner operators in the petroleum field to ameliorate the process of training and learning without stopping the real processes. The advantage of this approach is its adaptability as well as its possibilities of extension (addition of new functionalities). Moreover, the decomposition into sub-systems reduces significantly the complexity of the elements being implemented and therefore, allows a greatmodularity and a better legibility to the system. Our work is realised in collaboration with the production department of natural gas liquefaction (GL1/K Skikda), one of the principal hydrocarbons poles from SONATRACH complex in Algeria.

035: Impact of operator learning curve on success of percutaneous coronary intervention for chronic total occlusions

Percutaneous coronary intervention (PCI) for Chronic Total Occlusions (CTO) is associated with a higher failure rate than PCI for other lesion subsets. The aim of this study was to assess the impact of operator learning curve on success rate of PCI for CTO. The study included consecutive patients undergoing PCI for CTO at 3 tertiary cardiac centres between January 2004 and December 2011. To identify minimum case volume for optimum clinical benefit, CTO-PCI cases were chronologically ranked and stratified into 6 case volume groups, as 1 to 50 (beginner operators), 51 to 100, 101 to 150, 151 to 200, 201 to 250, >250, for several operators. A multivariable mixed effect logistic regression for clustered data was used to assess the impact of case volume on PCI failure after adjustment for patient characteristics, lesion difficulty graded by angiographic score, vessel site, procedural techniques. A total of 1261 patients, median 63 yrs-old (25th-75th percentile, 55–72), undergoing PCI for 1418 CTO were included. PCI success occurred in 1008 (71%) lesions. Crude success rate was 69.6%, 66.2%, 69.6%, 76.1%, 70.2%, 77.8% across the 6 ordered case volume groups, respectively, p=0.04. At multivariable logistic regression, increasing case volume across the six categories was significantly associated with successful PCI (odds ratio (OR) 1.22, 95% confidence interval (CI) 1.13.–1.32, p<0.001). The OR of success increased substantially and significantly with a case volume of at least 151 to 200, as compared to 1 to 50 case volume (2.09, 95% CI 1.18–3.70, p=0.012), reaching the highest value in case volume >250 (OR 2.85, 95% CI 1.87–4.34, p<0.001, while the increase in odds ratio for case volumes < 151, as compared to 1 to 50 case volume, did not reach the statistical significance. Operator experience in PCI for CTO is an independent predictor of success. A minimum case volume >150 is required to increase significantly the chance of success compared to beginner operators

Measurement of intracranial translucency using three‐dimensional ultrasound and Volume IT™

To establish the reference range of intracranial translucency (IT) in the Korean population, and to evaluate whether Volume IT™ is a reliable technique for measuring IT. We retrospectively analyzed the IT of 93 singleton fetuses at 10.5 to 12.6 weeks of gestation using previously obtained three-dimensional volume data. The IT was measured manually and automatically using Volume IT™ in each fetus by one experienced and one beginner operator. We measured the IT values according to the crown-rump length and evaluated whether Volume IT™ can successfully measure the IT. Inter-observer agreement and intra-observer reproducibility were analyzed using the intraclass correlation coefficients (ICC), and the IT measurements obtained by the experienced operator using the manual and automated methods were then compared using the Bland-Altman plot and ICC. Among 93 cases, 2 were lost to follow-up after the first trimester scan and were excluded from further evaluation. Both operators identified the fourth ventricle in all 91 cases using Volume IT™. The experienced and beginner operators were able to measure the IT in 89 (98%) fetuses, with 4 and 13, respectively, requiring adjustments. The IT values increased with gestational age (correlation coefficient, r=0.491, P <0.0001). Inter-operator agreement was moderate (ICC=0.580 for automated and 0.546 for manual measurements), and intra-operator reproducibility was highest for automated measurements by the experienced operator (ICC=0.944). Agreement of the IT values between the manual and automated methods was high (ICC=0.950). Our results provide the reference range of IT in the Korean population. The Volume IT™ may be a reliable technique for measuring IT.

De la microchirurgie à la « supermicrochirurgie » : étude expérimentale de faisabilité et perspectives

Supermicrosurgical techniques developed for the anastomoses less or equal to 0.5mm show convincing results in specialized centers and with an advanced instrumentation. Can we integrate supermicrosurgical training animal models in the current teaching program of microsurgery?. Ten arterial anastomoses of the inferior epigastric artery (diameter less than or equal to 0.5mm) were performed consecutively in five rats by the same beginner operator in microsurgery, with standard microsurgical set of instruments. The intravascular stenting anastomosis method was used with 11-0nylon sutures. The immediate patency and flap survival on postoperative day three was assessed. The duration of each anastomosis was measured. The mean diameter of the arteries was 0.4mm. The average time for each anastomosis was 30minutes with a maximum of 55minutes and a minimum of 18minutes. The average number of stitches was 5.5. The immediate patency was 100% with a 70% success rate at the third day. There are several applications of supermicrosurgical techniques, especially in hand surgery, lymphoedema surgical treatment and for perforator-to-perforator flaps. The intravascular stenting method allows fast learning of the technique with a satisfactory success rate despite non-specific instrumentation. Furthermore, this method could easily be integrated among the microsurgical courses of many universities.

Risk factors for bleeding after endoscopic submucosal dissection for gastric lesions

To assess risk factors for bleeding after gastric endoscopic submucosal dissection (ESD) and to develop preventive measures. This retrospective study was performed in a tertiary referral center. A total of 328 patients underwent ESD for 398 gastric neoplasms between July 2007 and June 2009. The main outcome was association between post-ESD bleeding and the following: age; sex; comorbidities; daily use of medicine potentially related to gastric injury/bleeding; location, size, and histological depth of lesions; ulceration; experience of operator coagulating the ulcer floor, and duration of operation. We also determined the relationship between the location of post-ESD bleeding and risk factors for hemorrhage. Univariate analysis revealed significant risk factors: tumor location [odds ratio (OR), 2.86; 95% CI: 1.21-6.79, P = 0.024], coagulator experience (OR, 4.29; 95% CI: 1.43-12.86, P = 0.009), and medicine potentially related to gastric injury/bleeding (OR, 2.80; 95% CI: 1.14-6.90, P = 0.039). Multivariate logistic regression analysis confirmed significant, independent risk factors: tumor in lower third of stomach (OR, 2.47; 95% CI: 1.02-5.96, P = 0.044), beginner coagulator (OR, 3.93; 95% CI: 1.29-11.9, P = 0.016), and medicine (OR, 2.76; 95% CI: 1.09-6.98, P = 0.032). We classified cases of post-ESD bleeding into two groups (bleeding at the ulcer margin vs bleeding at the center) and found that bleeding at the margin occurred more frequently with beginner coagulators compared with experts (OR, 16.00; 95% CI: 1.22-210.59, P = 0.040). Beginner coagulators, tumor in the antrum, and medicines were significant risk factors for post-ESD bleeding. Bleeding at the ulcer margin frequently occurred with beginner operators.

Region of Attraction for Safe Manual Control of Pendulum System

The purpose of this study is to develop a skill acquisition support system for stabilizing operation of a pendulum system by EMG signals. Recently, many mechatronics using EMG signals as inputs are developed. However, it is difficult for beginner operators to control such mechatronics, and long time training is required to acquire the control skills. Therefore, this paper considers about development of a skill acquisition support system utilizing Safe Manual Control (SMC) to help beginners' training. We moreover introduce an impact factor to tune how actively an automatic support in SMC works because the support level should be adjusted according to the acquired skill level of trainees. In those case, stability of SMC may not be guaranteed generally. Hence, the region of attraction of SMC with the impact factor is analyzed for a pendulum on a cart system.