Stop Technique Research Articles

Technical evaluation of a prototype ratio 29:1 grid for adult patient cardiovascular angiography imaging conditions

The purpose of this work was to assess technical performance of a prototype high-ratio (r29), 80 line cm−1 grid for imaging conditions which mimic those for adult cardiovascular angiography. The standard equipment r15, 80 line cm−1 grid was used as a reference. Plastic Water® LR phantoms with thickness in the range 20–44 cm were used to simulate adult patient attenuation and scatter. Grids were tested using x-ray field of view 20 and 25 cm and x-ray source to detector distance (SID) 107 and 120 cm. The primary transmission fraction (TP ) was measured using both narrow beam geometry and a lead beam stop (BS) technique. Scatter transmission (TS ) was measured with the lead BS technique. The quantum signal to noise ratio improvement factor (K SNR) was used to describe relative grid performance. The experimental conditions required revised theory to assess grid performance. Theory to account for the detector glare and underestimation of scatter intensity by the lead BS method was developed. Also, novel K SNR theory was developed to allow direct comparison of two grids operated at different SID. Mean TP was modestly lower for the r29 versus r15 grid (0.69 versus 0.75). When tested under equivalent scatter condition, TS of the r29 grid was approximately ½ that of the r15 grid (0.18 versus 0.34). K SNR of the r29 grid at SID 120 cm compared to the r15 grid at SID 107 cm increased linearly with phantom thickness (range 1.0 to ∼1.16). Findings of this work indicate that the r29 grid used at SID 120 cm is expected to provide improved image quality (or reduced patient radiation dose) when compared to the r15 grid used at SID 107 cm for adult cardiovascular patients and that the potential benefit of the r29 grid increases with patient thickness >20 cm.

MACULAR OCT OUTCOMES OF PHACOEMULSIFICATION CATARACT SURGERY IN DIABETIC VERSUS NON DIABETIC PATIENTS

Background: Cataract surgery with phacoemulsification is one of the most common surgical procedures performed today .Compared to people without diabetes, diabetic patients have been shown to have an elevated risk of developing cataracts. Cataract surgery in diabetics is indicated not only to improve visual acuity, but also to allow assessment and treatment of fundus changes. Even in the absence of diabetic retinopathy, diabetes mellitus has been found to have about twice the occurrence rate of pseudophakic CME. Objectives: This study was done to document any subsequent post-phacoemulsification macular edema (PPME) as postoperative sequelae in the diabetic versus non-diabetic nuclear senile cataract patients. Methods: This study was conducted on patients complained from visually significant immature senile cataract in ophthalmology department at Sohag university hospital between January 2018 and December 2020.Corrected distance visual acuity, Keratomerty, refraction, slit-lamp examination, macular optical coherence tomography (OCT) and biometry. Phacoemulsification was performed to all patients by stop and shop technique. The macular OCT changes were documented preoperatively and at postoperative month 1, 3, 6. Results: 64 eyes of 64 patients with visually significant senile cataract were included 32eye of them were diabetics, (33 males, and 31 females), our study documented four cases of the entire 64 eyes (6%) complicated with PPME in groups A and B at the postoperative month 1. Both A and B groups exhibited the same incidence of postoperative macular edema i.e. two (6%) cases in each group. Conclusion: Our outcomes confirmed that there was a similar probability of PPME occurrence in both non-diabetic and diabetic patients as this probability was mostly related to the surgical procedure itself. Meanwhile, the non-diabetic PPME exhibited rapid and complete recovery within one month in comparison to the diabetic PPME that exhibited gradual and incomplete recovery during the postoperative six months follow-up period.

Comparing corneal outcome between femtosecond laser-assisted cataract surgery and conventional phaco surgery in Fuchs' endothelial dystrophy patients: a randomized pilot study with 6mo follow up.

To compare the corneal outcome in Fuchs' endothelial dystrophy (FED) patients between femtosecond laser-assisted cataract surgery (FLACS) and conventional phaco surgery (CPS). This was a randomized controlled study comparing one eye surgery by FLACS and the contralateral eye operated by CPS (stop and chop technique) in FED patients. Central corneal thickness, corneal light backscatter, corneal densitometry, and central corneal endothelial cell count and hexagonality (noncontact endothelial cell microscope), and corrected distance visual acuity (CDVA) were assessed preoperatively and at day 1, 40, and 180 postoperatively. Totally 31 patients (16 women) were included. At day 40 postoperatively, the mean endothelial cell loss (ECL) was 23.67% by FLACS and 17.30% by CPS (P=0.53). At day 180 postoperatively, ECL was 25.58% in FLACS and 21.32% in CPS (P=0.69). Densitometry data in all layers and all annuli from anterior layer to posterior layer in annuli 0-2, 2-6, 6-10 and 10-12, total densitometry with all layers and all annuli was performed. A significant difference was found in 6-10 (posterior layer) at day 1 with -1.42 grayscale units (GSU; 95%CI: -2.66 to -0.19, P=0.02). In 10-12 (anterior layer, central layer and all layers) at day 40 were significant different with 7.7 (95%CI: 1.89 to 13.50, P=0.009), 3.97 (95%CI: 0.23 to 7.71, P=0.03), 4.73 GSU (95%CI: 0.71 to 8.75, P=0.02), respectively. In the remaining parameters we found no difference between the two groups (P>0.05). Three CPS eyes suffered from corneal decompensation. There is no significant difference in corneal outcome between FLACS and CPS. Endothelial cell density and pentacam corneal outcome may be inadequate as outcome parameters in FED patients.

Early stopping technique using a genetic algorithm for calibration of an urban runoff model

ABSTRACT Identifying suitable parameter sets for use in catchment modelling remains a critical issue in hydrology. This paper describes an early stopping technique (EST) for use during calibration of a multi-parameter urban catchment modelling system. The proposed method takes advantage of MODE and lower confidence limit (LCL) functions in statistical analysis of spanning set of objective function values. The paper also introduces a monitoring process and regularization techniques to avoid under/overfitting during the calibration and to enhance generalisation performance. The methodology is assessed using SWMM and linked with a Genetic Algorithm for calibration of a Powells Creek catchment model in Sydney, Australia. Results demonstrate that the statistical spanning set analysis approach overcomes issues of poor interpretation and deterioration in the model’s generalisation properties. By stopping early, the calibration process avoided overfitting; this was indicated by too closely fitting to the calibration dataset and a failure to fit to the monitoring dataset.

Phaco chop versus stop and chop nucleotomy techniques: A comparative evaluation

To perform a comparative evaluation of phaco chop versus stop and chop nucleotomy techniques in phacoemulsification. Materials and Methods: 60 patients with uncomplicated senile cataract were included in this study which were randomly divided into phaco chop group (group 1) and stop and chop group. (group 2) with 30 patients each and each group had 10 patients each of nuclear sclerosis grade II, III and IV. The main parameters were effective phaco time, total balanced salt solution used, total phacoemulsification power, intraoperative complications and postoperative visual acuity on day 1, 1st week and 3rd week. Results: The mean effective phacoemulsification time was 30.33±3.77 seconds in group 1 and 31.63 ± 4.22 seconds in group 2. The mean total phacoemulsification power in group 1 was 38.97 ± 4.33% whereas 41.93 ± 7.09 % in group 2. The mean total BSSV used in group 1 was 111.67 ± 13.86 ml whereas 113.17 ± 19.94 ml in group 2. The difference between the two groups was not significant. All patients received BCVA of 6/6 in both the groups after 3 weeks. Conclusion: The stop and chop technique and phaco chop technique are equally efficacious for nuclear cracking in patients in terms of visual acuity but if we compare according to nuclear grading, stop and chop technique requires more phaco power, phaco time and balanced salt solution which can lead to higher endothelial cell loss in grade IV nuclear cataract. Keywords: Cataract, Nucleotomy, Phacoemulsification, Phaco chop, Stop and Chop.

Fixed Pattern Noise Reduction and Linearity Improvement in Time-Mode CMOS Image Sensors

In the paper, a digital clock stopping technique for gain and offset correction in time-mode analog-to-digital converters (ADCs) has been proposed. The technique is dedicated to imagers with massively parallel image acquisition working in the time mode where compensation of dark signal non-uniformity (DSNU) as well as photo-response non-uniformity (PRNU) is critical. Fixed pattern noise (FPN) reduction has been experimentally validated using 128-pixel CMOS imager. The reduction of the PRNU to about 0.5 LSB has been achieved. Linearity improvement technique has also been proposed, which allows for integral nonlinearity (INL) reduction to about 0.5 LSB. Measurements confirm the proposed approach.

Comparison of phacoemulsification parameters in eyes with and without exfoliation syndrome

To evaluate and to compare the phacoemulsification machine parameters in eyes with and without XFS, requiring cataract surgery. Patients who underwent phacoemulsification and in-the-bag IOL implantation for cataract were included in this retrospective study. All surgeries were performed by the same experienced surgeon using the stop & chop technique with the same phacoemulsification device (Infiniti Vision System, Alcon Laboratories, Inc., USA). Patients were divided into two groups according to the presence of exfoliation material (XFM). Each group consisted of consecutive patients. Their characteristics and intraoperative phacoemulsification parameters were compared. Sixty-eight eyes of 68 patients [29 in the exfoliation syndrome (XFS) (-) group, 39 in XFS (+)] were enrolled. There were no statistical differences regarding preoperative patient characteristics. There was a statistically significant difference in total U/S time, phaco time, aspiration time and estimated fluid used between the XFS (+) and XFS (-) groups (P=0.021, P=0.017, P=0.009 and P=0.002, respectively). Considering that the use of a CTR (capsule tension ring) might be an important factor potentially affecting surgical parameters, the data were analyzed accordingly. Aspiration time and estimated fluid used remained statistically significant (P=0.046 and P=0.017, respectively); however, although the U/S total and phaco time were found to be longer in XFS (+) group compared to XFS (-) group, the difference did not show statistical significance (P=0.061 and P=0.059, respectively). There were no differences between groups regarding endothelial cell loss or any other postoperative complications. The presence of XFS results in longer total U/S time, phaco and aspiration time and more estimated fluid used in phacoemulsification, but this prolongation does not result in additional complications.

In situ recovery of copper sulfide ores: Alternative process schemes for bioleaching application

There is a growing interest in exploring the application of bioleaching for treating copper sulfide ores of decreasing grade and located at larger depth by in situ recovery (ISR) for its potential savings in ore extraction, crushing, grinding and the avoidance of tailings. As copper sulfide ores are usually present in well consolidated rocks a crucial aspect for ISR to be successful is to increase the ore permeability in order to allow a good access of solution to the valuable metal values. However, in bioleaching an additional critical aspect is to guarantee an adequate supply of oxygen, the final electron acceptor in the reaction chain. Two alternative schemes to solve this issue are here characterized and compared using process simulation.One approach considers pre-treating the rock with hydrofracturing and/or confined blasting in order to create a network of cracks adequate for pumping the pressurized leaching solution into the ore bed in a saturated flow regime. In this scheme oxygen needs to be added in an external bioreactor where ferric iron is generated by bacterial oxidation of ferrous iron. A second approach considers pre-treating the ore by application of sublevel stopping techniques with partial removal of the rock to be able to irrigate the solution into the ore bed under an unsaturated flow regime. In this scheme oxygen can be directly supplied into the ore bed enabling in situ generation of ferric iron by the oxidative action of microorganisms present in the ore.The influence of irrigation rate, leaching solution concentration, bacterial population and ore bed dimensions on copper recovery and bioreactor requirements was assessed for these two process schemes. Some economic aspects of these two alternatives are discussed.

Estimating Mean of Maximum Fields Inside Reverberation Chambers Using Deep Neural Networks

Recently, there has been great interest in estimating the mean of the maximum field strength in a nested reverberation chamber in such conditions that the field coupled inside the equipment under test (EUT) deviates from the parent distribution, thus generating a non-Rayleigh distribution. For this purpose, a new regression model with the deep feedforward neural network is proposed to predict the mean of the maximum field inside a nested reverberation chamber configuration. In our proposed method, a frequency range that comprises the EUT in the overmoded regime is treated as an input of the network, and the mean of the maximum field is treated as the output of the network. Several networks with different numbers of hidden layers are trained, while adaptive learning rates and early stopping techniques are used to improve the network training process, subsequently reducing the uncertainties. After training, the networks are verified using a test set that is not implicitly employed during the training process. The testing and training mean-squared errors (625e-5 and 325e-5) with the network with five layers have a good agreement for a considered configuration, demonstrating a novel regression model that is able to rigorously extrapolate the mean of the maximum field in the other frequency steps that are not used in the training set.

Penetrating the influence of regularizations on neural network based on information bottleneck theory

Regularization is a very effective algorithm to solve overfitting problem in neural network, which improves the generalization ability of the model. However, their working mechanisms and the impact on the model performance have not been fully explored. In this paper, we study and analyze them using information bottleneck theory and one theory from human brain sensory system. We propose a metric to characterise the encoding length of hidden layers, named as AEntry value. Then, we implement extensive experiments on MNIST and FashionMNIST datasets with several commonly used regularization algorithms, and calculate the corresponding AEntry values. We analyze these results and obtain three conclusions. (1) The introduction of regularization influences the encoding of relative features with prediction task in neural network. The early stopping technique avoids introducing unrelated information with the task into the model by stopping the training process as an appropriate iterations. Laplace, Gaussian and Sparse Response regularizations compress the related representation and improve the performance of neural network by introducing the prior information into the model. In contrast, Dropout, Batch Normalization, and Layer Normalization increase the encoding length of features by adopting redundant representation to improve the performance. (2) The encoding of neural network does not satisfy the data processing inequality of information theory, which is mainly caused by redundant coding of extracted features. (3) The overfitting is caused by introducing irrelative information with the target. These results can give us insight into building more efficient regularization algorithm to improve the performance of neural network model.

Phacomulsification in senile white mature cataracts;its safety and efficacy

Abstract
 Purpose 
 To evaluate the intraoperative difficulty, complications and post operative outcome in patients with white mature cataracts undergoing phacomulsification and foldable intraocular lens implantation and to develop a strategy for achieving continuous curvilinear capsulorhexis in these cases.
 Study design
 Descriptive case series
 Place and duration 
 Ophthalmology department of Holy family hospital, Rawalpindi in six months interval since January 2017 to June 2017
 Material and Methods 
 50 Patients who had senile white mature cataract were enrolled in this prospective study .Detailed preoperative and intraoperative notes were made. A small capsulorhexis was attempted initially after staining capsule with trypan blue .An initial cut was made with cystotome and it was enlarged with utrata forceps. Endophacomulsification was done with stop and chop technique. Intraoperative difficulties related to continuous curvilinear capsulorhexis, phacomulsification and post operative visual outcomes were analyzed.post operative examinations were done at day 1,1st week,1st month and 3rd month.
 Results
 There were 28 males (56%) and 22 females (44%).The mean age was 63.18±7.997 standard deviation years(48-78).The mean preoperative best corrected visual acuity BCVA was 0.0276±0.013 (SD)Snellen, decimal(0.01-0.05) and the mean post operative BCVA was 0.638±0.305 (SD) Snellen, decimal(0.1-1.0) .Mean phaco time was 4.08±1.03 (SD)mins(2.08-6.66).The mean preoperative intraocular pressure IOP was 15.90±1.799 (SD)mmHg (12-22) and mean post op IOP was 11.98±2.035 (SD) mmHg(10-18) .Posterior capsular rupture occurred in 3 (6%) , vitreous loss occurred in 1 (2%) patients. 5 (10%) cases were converted to extra capsular cataract extraction (ECCE). Postoperatively 10 (20%) patients had transient corneal edema, 3 patients (6%) had persistent corneal edema and corneal burn treated with steroids and hyper osmotic agents.
 Conclusion 
 The intraoperative and postoperative complications rate is higher in white mature cataracts. White mature cataract is a challenge for cataract surgeon, yet by means of additional dyes and proper techniques and expertise, the rate of complications can be reduced.
 Keywords
 Phacomulsification, continuous curvilinear capsulorhexis, senile mature cataract, trypan blue, posterior capsular rupture, persistent corneal edema

Effects of ‘STOP’ Mindfulness on Decreasing Cortisol in Primigravida Mothers

<p><strong>Background: </strong>Stress in pregnant women may give different effects on the development of pregnancy. Mindfulness is an intervention which can be practiced independently by primigravida mothers for stress management. Stress is indicated by a biological parameter of cortisol levels. </p><p><strong>Purpose</strong><strong>:</strong> This study aimed to analyze the effects of mindfulness on decreasing cortisol levels in primigravida mothers. </p><p><strong>Method</strong><strong>s</strong><strong>:</strong> This study used a pretest-posttest quasy experimental design with a control group. The samples were 30 primigravida mothers who experienced stress in the area of public health centers in Semarang city. A consecutive sampling technique was used to select the samples. Mindfulness with STOP technique (Stop-Take a breath-Observe-Proceed) was given for four meetings for 60 minutes each. Before and after the implementation of mindfulness, 3 ml of blood was taken from the samples for the cortisol examination. Data were analyzed using a paired t-test.</p><p><strong>Results:</strong> The results showed that the majority of women (46.7%) were in the second trimester of pregnancy, and aged 20-35 years old (86.7%). The mean of cortisol level before and after the intervention was 180.60 and 152.50, respectively. There was a decrease in the level of cortisol after the implementation of mindfulness with a p-value of 0.000 (? <0.05).</p><strong>Conclusion:</strong> Mindfulness is effective in decreasing cortisol levels in primigravida mothers. Mindfulness can be used as an intervention to increase the self-reliance of pregnant women for stress management.

A Power-Efficient Digital Technique for Gain and Offset Correction in Slope ADCs

In this brief, a power-efficient digital technique for gain and offset correction in slope analog-to-digital converters (ADCs) has been proposed. The technique is especially useful for imaging arrays with massively parallel image acquisition where simultaneous compensation of dark signal non-uniformity (DSNU) as well as photo-response non-uniformity (PRNU) is critical. The presented approach is based on stopping the ADC clock by a specially prepared clock-enable pulse sequence. This brief describes the properties of ADCs utilizing this clock stopping technique, including power dissipation, integral, and differential nonlinearity. The experimental validation has been performed for the ASIC implementation of the 128-pixel imager containing photo-sensors integrated with ADCs. Finally, a modification is proposed that increases the accuracy of the gain correction. Measurements confirm functionality of the proposed approach. Reduction of the PRNU (to ~0.4 LSB) has been achieved as well.

A gas-jet apparatus for high-resolution laser spectroscopy on the heaviest elements at SHIP

Laser spectroscopy enables the determination of fundamental atomic and nuclear properties with high precision. In view of the low production rates of the heaviest elements, a high total efficiency is a crucial requirement for any experimental setup to be used in on-line experiments. The setup requires the use of gas stopping techniques to slow down the radionuclides of interest. In previous studies laser spectroscopy was performed inside a gas-filled stopping cell with a limited spectral resolution of a few GHz. Collisional broadening inside stopping cells ultimately limits the precision of laser spectroscopic studies and hampers in particular hyperfine spectroscopy. The spectral linewidth is reduced by an order of magnitude when the laser spectroscopy is performed in a well-collimated gas jet formed by the exit nozzle of a gas stopping cell. In addition, the exposure of the jet to high-repetition rate laser light which saturates the optical transitions allows maintaining a high total efficiency. Here, we present a new setup dedicated to laser spectroscopy of the heaviest elements with an improved resolution, which is presently under construction. This setup combines the efficient filament neutralization demonstrated for nobelium with the improved resolution of in-gas-jet spectroscopy.

Management of an Immature Tooth Using MTA and Composite Canal Reinforcement

Complete debridement, thorough disinfection and optimal sealing of the root canal system are the major challenges associated with endodontic treatment of teeth with open apices. In such teeth, thin radicular dentinal walls are susceptible to fracture. To ensure a better prognosis in such fractured prone thin dentinal walls, internal radicular reinforcement with various adhesive materials like glass ionomer cement, composites is recommended. A 15-year boy reported to the department with tooth #21showing large periapical radiolucency in association with an immature tooth having flared wide root canal. Here presenting a management of this case using MTA as an apical plug and composite as canal reinforcement material. This case report highlights the use of apical stop and canal reinforcement technique for management of immature teeth with thin radicular walls.

Phacoemulsification of Hard Nuclei on a Single-Piece Foldable Acrylic Intraocular Lens

Objectives: We describe a technique for phacoemulsification of hard (brunescent and white) cataract after implantation of a foldable acrylic posterior chamber IOL (PCIOL) between the hard nucleus and the posterior capsule. This new technique was compared with the standard phacoemulsification. Methods: Interventional randomized case series of 64 eyes of 56 patients with senile mature white or hard brunescent cataract. The first 32 eyes were randomized for standard phacoemulsification using stop and chop technique and one-piece foldable acrylic PCIOL (soft haptics). The second 32 eyes were randomized for the same type of PCIOL implanted between the hard nucleus and the posterior capsule before starting phacoemulsification “the implant pre-phaco” group. Results: In each group 2 eyes developed transient corneal edema. Iris phaco-burn developed in 2 eyes of the standard phacoemulsification group and one eye of the “implant pre-phaco” group. Posterior capsule rupture (PCR) with vitreous prolapse occurred in 3 eyes of the standard phacoemulsification group. In the “implant pre-phaco” group one eye developed PCR with no vitreous prolapse. The difference in PCR between the 2 groups was not statistically significant but the vitreous prolapse in the AC was significantly higher in the standard phacoemulsification group. IOL decentration or dropped lens fragments did not occur in either group. Conclusion: The IOL behind the hard nucleus acts as barrier shield that covers and protects the posterior capsule and the anterior vitreous face. This could make phacoemulsification of hard cataracts safer.

Constitutive Modelling of INCONEL 718 using Artificial Neural Network

Artificial neural network is used to model INCONEL 718 in this paper. The model accounts for precipitate hardening in the alloy. The input variables for the neural network model are strain, strain rate, temperature and microstructure state. The output variable is the flow stress. The early stopping technique is combined with Bayesian regularization process in training the network. Sample and non-sample measurement data were taken from the literature. The model predictions of flow stress of the alloy are in good agreement with experimental measurements.

Análisis de la validez de las ecuaciones de estimación del 1RM con técnica de parada: una nueva propuesta

<p>El objetivo de esta investigación es validar nuevas ecuaciones de regresión para estimar el valor de fuerza dinámica máxima absoluta (1RM) mediante test de máximo número de repeticiones hasta el fallo muscular (nRM) ejecutados con técnica de parada o stop. Igualmente, se estudian los niveles de validez que presentan las ecuaciones que ya se encuentran actualmente definidas en la literatura internacional para estimar la magnitud de la carga (%1RM) y el valor de 1RM a partir de un test nRM en ejecuciones con técnica de parada. Los resultados indican que las nuevas ecuaciones propuestas en esta investigación [1RM en Press Banca = masa desplazada en kg (-0,01841*nRM)+0,981; 1RM en Sentadilla Completa = masa desplazada en kg (-0,01176*nRM)+0,975] muestran indicadores sustancialmente mejores de validez(ET = 1,8-2,2 kg; R<sup>2</sup> = 0,956-0,988), y por lo tanto de mayor capacidad predictiva, que el resto de ecuaciones definidas en la literatura internacional hasta la fecha.</p>

The Prediction of Three Key Properties on Coalbed Methane Reservoir Using Artificial Intelligence

This research focuses on creating the prediction tools for the three key properties in coalbed methane (CBM) reservoir; the properties are gas content, Langmuir parameters, and permeability. Basically, their roles are to describe the gas in place and also future dynamic behavior of CBM reservoir. These three key properties are tried to be predicted with open-hole data as the inputs.It uses artificial neural network (ANN) and adaptive neuro fuzzy inference system (ANFIS) to generate the prediction tools. It is started from data preparation and processing, then pattern or function identifications, and finalized by validation and testing. Several training algorithms are applied for ANN such as adaptive gradient descent (ANN_GDX), Levenberg-Marquardt (ANN_LM), resilient backpropagation (ANN_RP), scaled conjugate gradient (ANN_SCG), and Bayesian regularization algorithm (ANN_BR). The first fives employ the early stopping technique for regularization, and the last one does Bayesian regularization. On the other hand, the ANFIS will use only early stopping technique.Based on this research, it is concluded that both ANN and ANFIS are able to identify the patterns or function between open-hole log data and the three key properties (TKP). Furthermore, it can be concluded that ANN_LM, ANFIS, and ANN_BR are the best selected algorithms which resulted the lowest error of TKP’s predictions.

Research on the automatically trajectory control of a spherical isolation plug in subsea pipeline

The rapid growth demanding for oil and gas resources has gradually driven the fossil energy exploitation from the land to the ocean. Technology shifts from manually operated oil fields to the remotely operated oil fields is necessary, and robotic assistance to human cognition is essential. Hot tapping and line stop techniques, as a great method for the replacement of the risky pipelines without disrupting the service to customers, demands for the automation to improve the efficiency and reliability. In this paper, automatically trajectory control of a spherical isolation plug in subsea pipeline was investigated. Mathematical model for the spherical plug head insertion was presented, and two control algorithms for the automatically insertion of the plug were proposed, named the rotation angle based control algorithm and the vertical displacement based control algorithm. Simulation was conducted and the results indicate that the vertical displacement based control algorithm owes better performance than the rotation angle based control algorithm. The accuracy and efficiency of the vertical displacement based control algorithm was then experimentally researched. The results in this paper can provide references for the automatically trajectory control of an isolation plug, as well as improve the accuracy and reliability of offshore hot tapping.