Small Workspace Research Articles

Is Intraoperative Blood Loss Underestimated in Patients Undergoing Laparoscopic Hepatectomy?

Less intraoperative blood loss is frequently reported as an advantage of laparoscopic hepatectomy (LH) over open hepatectomy (OH). However, the small work space during laparoscopic surgery could lead to insufficient blood suction from the abdominal cavity, with possible underestimation of intraoperative blood loss. This study compared estimated blood loss (E-BL) with intraoperatively counted blood loss (IC-BL) in patients undergoing LH. This study included 110 consecutive patients undergoing partial hepatectomy for solitary liver tumors (59 had OH and 51 had LH). IC-BL and E-BL were determined, and the difference between them was calculated based on the surgical approach. Factors affecting the difference were investigated. IC-BL was quantified from the suction fluid volume and weight of surgical gauzes used for blood and fluid collection. E-BL was calculated with the total blood volume and change in hematocrit. Although there were no significant differences between IC-BL and E-BL in the OH group (292 ± 198 vs. 259 ± 167mL, p = 0.1239), E-BL was significantly greater than IC-BL in the LH group (273 ± 166 vs. 128 ± 177mL, p < 0.0001). Percentage of patients with E-BL > IC-BL in the LH group was significantly greater than in the OH group (86.3 vs. 42.4%, p < 0.0001). The surgical approach (OH/LH) was the only significant independent factor determining E-BL > IC-BL status. E-BL was significantly greater than IC-BL only in patients undergoing LH, and the surgical approach (OH/LH) was the only factor affecting E-BL > IC-BL status. These results suggest that intraoperative blood loss may be underestimated during LH.

Closed loop control of microscopic particles incorporating steady streaming and visual feedback.

Automatic manipulation of microscopic particles is very important in biology, especially in new lab-on-chip systems for automatic testing and DNA manipulation. We suggest a particle manipulation system (PMS) based on vibrating piezoelectric beams creating steady streaming flow in a viscous liquid. The flow is nearly unidirectional and it is used to control the position and velocity of the particles in the workspace of the PMS. The particles position in the PMS are controlled by visual feedback. This study presents the manipulation method, the system's model describing its behavior and characterizes experimentally its performance. The PMS is capable moving a 2-200 μm particle in a workspace of 8x8 mm2 with an absolute accuracy of 0.2 μm. The characteristic velocity in 500 cP Si oil, is 20 μm/s using an actuation voltage amplitude of 5 V and can reach 250 μm/s using 15 V respectively. We can also move a constellation of several particles in various sizes without changing the distance between them. The accuracy of the manipulation can be increased by enhancing the amplification of the microscope on the expanse of a smaller workspace field of view.

USING THE SIMULATION PROGRAM FOR THE DESIGN AND OPTIMIZATION OF THE PRODUCTION LINE

Urgency of the research. Increasing productivity while maintaining sufficient production quality is one of the main crite-ria for maintaining competitiveness. An appropriate way is to automate and robotize the production process. In order for robotization to succeed, all design steps need to undergo indepth research. Target setting. The aim is to design a robotic device (robotic line) capable of increasing the production of components in a smaller workspace from 91,000 to 160,000 per year for each of the 7 types of components. Actual scientific researches and issues analysis. The introduction of robotic devices into production systems is devoted to a large part of the publication. In general, it is possible to state that the robot deployment is specific and depends on the partic-ular manufacturing process. For this reason, it is necessary to carry out a new analysis of the suitability of the robot for each manufacturing process, supported by off-line simulation. Uninvestigated parts of general matters defining. This article focuses on a specific workplace solution that uses one type of robot delivered by a parent company. The use of a different robot type with more appropriate parameters was not feasible in financial terms. The research objective. The aim is to design the most suitable placement of production machines against the position of the industrial robot. Then analyse all the robot's working moves so that it can be manipulated by one of the 7 types of component on the line, with a production increase of 483.000 pieces per year. The statement of basic materials. Simulating the production workspace in the offline environment allows you to optimize your design before it is actually created on the selected desktop. This reduces the development costs and saves the total time when the work is completed. Conclusions. The article describes the problems of design, optimization and simulation of a robot equipped workplace. For optimizing workplace was precisely defined robot type when, which limited the use of the robot from better parameters. Using the robot can increase workplace productivity while reducing the work area. With the implementation of the proposal, the target was achieved to increase workplace output by 483.000 components/year.

Smooth assembled mappings for large-scale real walking

Virtual reality applications prefer real walking to provide highly immersive presence than other locomotive methods. Mapping-based techniques are very effective for supporting real walking in small physical workspaces while exploring large virtual scenes. However, the existing methods for computing real walking maps suffer from poor quality due to distortion. In this paper, we present a novel divide-and-conquer method, called Smooth Assembly Mapping (SAM), to compute real walking maps with low isometric distortion for large-scale virtual scenes. First, the input virtual scene is decomposed into a set of smaller local patches. Then, a group of local patches is mapped together into a real workspace by minimizing a low isometric distortion energy with smoothness constraints between the adjacent patches. All local patches are mapped and assembled one by one to obtain a complete map. Finally, a global optimization is adopted to further reduce the distortion throughout the entire map. Our method easily handles teleportation technique by computing maps of individual regions and assembling them with teleporter conformity constraints. A large number of experiments, including formative user studies and comparisons, have shown that our method succeeds in generating high-quality real walking maps from large-scale virtual scenes to small real workspaces and is demonstrably superior to state-of-the-art methods.

Calibrate parallel machine tools by using interval type-2 fuzzy interpolation method

This paper is an extended research of our previous study, in which only type-1 fuzzy system was discussed, for a novel technique used in the pose error compensations for parallel machine tools calibration process based on an interval type-2 fuzzy error interpolation (IT2FEI) method. Robot calibrations can be classified into model-based and modeless methods. Either inverse or forward kinematic models need to be used in the traditional calibration methods to perform the identification and compensation of the pose errors for parallel machine tools. Instead of using a model, the proposed method presents a modeless technique combined with an interval type-2 fuzzy interpolation method to obtain the same or higher calibration accuracy when a small workspace is adopted. Simulated results show that not only the robot compensation accuracy can be improved but also the calibration process can be significantly simplified, and it is more suitable for practical applications.

LZ77 Computation Based on the Run-Length Encoded BWT

Computing the LZ77 factorization is a fundamental task in text compression and indexing, being the size z of this compressed representation closely related to the self-repetitiveness of the text. A long-standing problem is to compute LZ77 using small working space. Considering that $$\mathcal {O}(z)$$ words of space can be significantly (up to exponentially) smaller than the size n of the input text, even succinct and entropy-compressed solutions are often unduly memory demanding. In this work we focus on an important measure of text repetitiveness: the number $$r$$ of equal-letter runs in the Burrows–Wheeler transform of the reversed input text. As z, the measure $$r$$ is closely related to the number of repetitions in the text and can be exponentially smaller than n. We describe two algorithms computing LZ77 in $$\mathcal {O}(r\log n)$$ bits of working space and $$\mathcal {O}(n\log r)$$ time. Roughly speaking, our algorithms store a constant number of memory words per BWT run to keep track of first-last run-positions and a suitable indexing mechanism to sample the runs of the BWT (instead of its positions). Important consequences of our results include (i) the possibility to convert from RLBWT- to LZ77-based compressed formats without first decompressing the text, and (ii) the existence of asymptotically-optimal construction algorithms for repetition-aware self-indexes based on these compression techniques. We finally describe an implementation of our solutions and present extensive experiments on highly repetitive datasets. Our algorithms use a working space as small as 1% of the dataset size and are two to three orders of magnitude more space-efficient (albeit slower) than existing solutions based, respectively, on entropy compression and suffix arrays.

Easy and Fast Reconstruction of a 3D Avatar with an RGB-D Sensor.

This paper proposes a new easy and fast 3D avatar reconstruction method using an RGB-D sensor. Users can easily implement human body scanning and modeling just with a personal computer and a single RGB-D sensor such as a Microsoft Kinect within a small workspace in their home or office. To make the reconstruction of 3D avatars easy and fast, a new data capture strategy is proposed for efficient human body scanning, which captures only 18 frames from six views with a close scanning distance to fully cover the body; meanwhile, efficient alignment algorithms are presented to locally align the data frames in the single view and then globally align them in multi-views based on pairwise correspondence. In this method, we do not adopt shape priors or subdivision tools to synthesize the model, which helps to reduce modeling complexity. Experimental results indicate that this method can obtain accurate reconstructed 3D avatar models, and the running performance is faster than that of similar work. This research offers a useful tool for the manufacturers to quickly and economically create 3D avatars for products design, entertainment and online shopping.

Orientation Workspace and Stiffness Optimization of Cable-Driven Parallel Manipulators With Base Mobility

Cable-driven parallel manipulators (CDPM) potentially offer many advantages over serial manipulators, including greater structural rigidity, greater accuracy, and higher payload-to-weight ratios. However, CDPMs possess limited moment resisting/exerting capabilities and relatively small orientation workspaces. Various methods have been contemplated for overcoming these limitations, each with its own advantages and disadvantages. The focus of this paper is on one such method: the addition of base mobility to the system. Such base mobility gives rise to kinematic redundancy, which needs to be resolved carefully in order to control the system. However, this redundancy can also be exploited in order to optimize some secondary criteria, e.g., maximizing the size and quality of the wrench-closure workspace with the addition of base mobility. In this work, the quality of the wrench-closure workspace is examined using a tension-factor index. Two planar mobile base configurations are investigated, and their results are compared with a traditional fixed-base system. In the rectangular configuration, each base is constrained to move along its own linear rail, with each rail forming right angles with the two adjacent rails. In the circular configuration, the bases are constrained to move along one circular rail. While a rectangular configuration enhances the size and quality of the orientation workspace in a particular rotational direction, the circular configuration allows for the platform to obtain any position and orientation within the boundary of the base circle. Furthermore, if the bases are configured in such a way that the cables are fully symmetric with respect to the platform, a maximum possible tension-factor of one is guaranteed. This fully symmetric configuration is shown to offer a variety of additional advantages: it eliminates the need to perform computationally expensive nonlinear optimization by providing a closed-form solution to the inverse kinematics problem, and it results in a convergence between kinematic singularities and wrench-closure singularities of the system. Finally, we discuss a particular limitation of this fully symmetric configuration: the inability of the cables to obtain an even tension distribution in a loaded configuration. For this reason, it may be useful to relax the fully symmetric cable requirement in order to yield reasonable tensions of equal magnitude.

Trajectory Tracking of a Planer Parallel Manipulator by Using Computed Force Control Method

Despite small workspace, parallel manipulators have some advantages over their serial counterparts in terms of higher speed, acceleration, rigidity, accuracy, manufacturing cost and payload. Accordingly, this type of manipulators can be used in many applications such as in high-speed machine tools, tuning machine for feeding, sensitive cutting, assembly and packaging. This paper presents a special type of planar parallel manipulator with three degrees of freedom. It is constructed as a variable geometry truss generally known planar Stewart platform. The reachable and orientation workspaces are obtained for this manipulator. The inverse kinematic analysis is solved for the trajectory tracking according to the redundancy and joint limit avoidance. Then, the dynamics model of the manipulator is established by using Virtual Work method. The simulations are performed to follow the given planar trajectories by using the dynamic equations of the variable geometry truss manipulator and computed force control method. In computed force control method, the feedback gain matrices for PD control are tuned with fixed matrices by trail end error and variable ones by means of optimization with genetic algorithm.

A Survey of Work-Related Musculoskeletal Disorders Among Otolaryngologists.

There are increased reports of prevalence of work-related musculoskeletal disorders (WRMSDs) in surgeons performing minimal access surgeries. Due to the nature of the speciality, otolaryngologists spend their work days in performing markedly precise procedures in small workspaces i.e. the patients' ear, nose and throat. Due to this, they frequently adopt awkward neck, back and shoulder postures while using devices like otoscope, endoscope and microscope. The field of otolaryngology has barely received any attention with respect to ergonomic assessment. Thus, the aim of this study was to find out the prevalence of WRMSDs in otolaryngologists in Mumbai and Navi Mumbai. A pre-validated, structured questionnaire was distributed to 150 otolaryngologists. Seventy-three otolaryngologists responded to the questionnaire. The questionnaire comprised of demographic and workload data, report of musculoskeletal symptoms and otolaryngologists' interpretation of casual and preventive factors of symptoms at workplace. Response rate of the survey was 48.6%. The total prevalence of WRMSDs in the otolaryngologists was 87.67%. Majority of those surveyed reported that they suffered from musculoskeletal problems which they attributed to the ergonomic flaws encountered during surgery (60.27%) and OPD (69.86%) respectively. Pain and discomfort during surgery experienced by the surgeons were most frequently attributed to the awkward and sustained postures adopted during surgery. Effective time management, ergonomically apt postures, intermittent change of posture, using back rest and availing skilled assistance during OPD and surgery, were the self-assessed corrective measures suggested by the respondents. The otolaryngologists' job profile puts them at high risk for WRMSDs.

Trajectory tracking through overwhelming control of human vertebrae as a hybrid manipulator

Industrial robots, generally, are composed of architecture with serial manipulators having large workspace but these suffer from several drawbacks, such as low accuracy and low load-carrying capacity. Similarly, the parallel architecture robots have better accuracy but small workspace. Therefore, the combination of serial and parallel chain architectures has become attractive as hybrid manipulators over the last two decades. A planar hybrid manipulator is proposed here and this is made by placing a planar parallel manipulator, having three degrees of freedom, each over the other in series so as to increase its load-carrying capacity and then it is modeled with the help of the bond graph approach. The human vertebrae are considered as a hybrid manipulator in this paper. The translation of the human vertebrae model on the frontal plane and lateral bending in the right- and left-hand directions are proposed here to increase the flexibility of the body part of humanoid robots used in industries and sports so that they can execute spine bending activities. The forward and inverse models for the manipulator are presented and the system inversion is carried out through the overwhelming controller. Finally, the simulation results for trajectory tracking of left-hand lateral bending in the frontal plane is done with or without the consideration of leg inertia and conclusions are presented to show that response follows the command within acceptable limits.

動作範囲に制限のあるマスタアームによる直感的遠隔操縦法の検討

We proposed a new teleoperation control method by using a master control device with small working space. The proposed method sets the slave velocity based on the master velocity. Changing the slave velocity by the master velocity, the operator can control the slave arm freely and intuitively using a small working space master device. In this paper, we propose a new scale conversion method that are expected to be better than the previously proposed. The new scale conversion methods determine the position scale directly based on the master velocity. We tested the new scale conversion method and the result of experiment is shown.

Preliminary Study of Video-Based Pediatric Endoscopic Surgical Skill Assessment Using a Neonatal Esophageal Atresia/Tracheoesophageal Fistula Model.

Thoracoscopic esophageal atresia/tracheoesophageal fistula (EA/TEF) repair in neonates is technically difficult because of the small working space and fragility of tissues. This study aimed to show the construct validity of the neonatal EA/TEF simulator by video-based assessment of endoscopic suturing skill. A rapid-prototyped neonatal chest model with an artificial esophagus model similar to the actual neonatal esophagus was developed. Forty pediatric surgeons performed an endoscopic intracorporeal suturing task and a knot-tying task using the model, and a questionnaire survey was administered. Each task was video recorded and assessed using two skill assessment methods (the 29-point checklist method and the error assessment sheet method). The task completion time and the number of manipulations were measured. With regard to experience in performing thoracoscopic TEF repair, the experienced surgeons (ESs, ≥3 EA/TEF repair experiences, n = 6) were significantly superior to the inexperienced surgeons (ISs, <3 experiences, n = 34) in all metrics. Upon comparison by the pediatric Endoscopic Surgical Skill Qualification (ESSQ) status, there were no significant differences in all metrics between the ESSQ-qualified (n = 15) and nonqualified (n = 25) surgeons. The qualified ESs (n = 6) were significantly superior to the qualified ISs (n = 9) in all metrics. Video-based endoscopic surgical skill assessment using the neonatal EA/TEF simulator could differentiate ESs from ISs. The construct validity of the simulator was demonstrated, and the simulator would be useful especially for practicing thoracoscopic EA/TEF procedures.

Techniques to perform robotic left adrenalectomy in the obese patient.

Minimally invasive adrenalectomy may be associated with reduction in postoperative pain, morbidity, and length of stay and, as a result, has become a preferred approach for many adrenal tumors. Left-sided adrenal tumors, however, are particularly challenging to address in the morbidly obese patient due to difficulties in maintaining exposure and dissection. The robotic platform offers instruments with greater degrees of freedom that aid in retraction and dissection, especially of the adrenal vein, but fixed patient positioning and the large distance needed between patient ports to avoid arm collisions can be restrictive in patients with a large amount of retroperitoneal fat and small working space. We demonstrate robotic left adrenalectomy (RLA) in a consecutive series of patients with a mean weight of 99 kg and mean BMI of 36. Techniques to safely and efficiently perform RLA in obese patients are stepwise demonstrated, including (1) Patient positioning, (2) Management of the pannus, (3) Customized port placement, (4) Medial retraction of the pancreas, (5) Finding the left adrenal vein, and (6) Management of bleeding. Intraoperative videos from multiple patients also show surgical pitfalls, examples of poor port placement, arm collisions, alternative approaches to the vein, and techniques to control unexpected bleeding. All patients in the series underwent successful RLA with negative margins, no major intra- or postoperative complications, and discharge on POD 1-2. Though poor exposure due to patient body habitus is a relative contraindication, even large left-sided adrenal tumors can be safely approached robotically while adhering to oncologic principles, as is demonstrated in this video.

Toward Improving Transurethral Prostate Surgery: Development and Initial Experiments with a Prototype Concentric Tube Robotic Platform.

Despite the potential clinical advantages of holmium laser enucleation of the prostate (HoLEP), there has been reluctance of the urologic community to adopt the procedure, as a result of a perceived steep learning curve. Thus, we sought to design and develop a transurethral endoscopic robotic platform for HoLEP. We developed a novel transurethral, concentric tube robotic platform for HoLEP. We conducted magnetic tracking experiments to compare movements of the end effectors of the robot with those of a rigid endoscope. Additionally, we tested the robot on an HoLEP simulator and with a human cadaveric prostate to assess its ability to maneuver within a small working space. In the prostate scanning experiment, the area reached by the robot represents a 65% improvement vs the area accessible by a rigid endoscope without tissue deformation. Additionally, the robot performed well within the confines of the prostatic urethra and was able to successfully complete prostate lobe enucleation, on both the HoLEP simulator and with a human cadaveric prostate. We have developed a concentric tube robotic platform that is passed through a standard endoscope that is capable of producing complex movements of the end effectors. We have shown that these movements of the concentric tube manipulators are capable of performing tasks that may eventually translate into improved ease of performing HoLEP.

Transforming the multifluid PPM algorithm to run on GPUs

In the past several years, there has been much success in adapting numerical algorithms involving linear algebra and pairwise N-body force calculations to run well on GPUs. These numerical algorithms share the feature that high computational intensity can be achieved while holding only small amounts of data in on-chip storage. In previous work, we combined a briquette data structure and a heavily pipelined CFD processing of these data briquettes in sequence that results in a very small on-chip data workspace and high performance for our multifluid PPM gas dynamics algorithm on CPUs with standard sized caches. The on-chip data workspace produced in that earlier work is not small enough to meet the requirements of today’s GPUs, which demand that no more than 32 kB of on-chip data be associated with a single thread of control (a warp). Here we report a variant of our earlier technique that allows a user-controllable trade-off between workspace size and redundant computation that can be a win on GPUs. We use our multifluid PPM gas dynamics algorithm to illustrate this technique. Performance results for this algorithm in 32-bit precision on a recently introduced dual-chip GPU, the Nvidia K80, are 1.7 times that on a similarly recent dual CPU node using two 16-core Intel Haswell chips. The redundant computation that allows the on-chip data context for each thread of control to be less than 32 kB is roughly 9% of the total. We have built an automatic translator from a Fortran expression to CUDA to ease the programming burden that is involved in applying our technique.

전방향 이동 메커니즘을 적용한 콘크리트 폴리싱 로봇의 성능평가

Article history: In the construction industry, concrete polishing is used to grind and rub the surface of concrete grounds with polishing machines to increase the strength of the concrete after deposition. Polishing is performed manually in spite of the generation of dust and the requirement of frequent replacements of the polishing pad. The concrete polishing robot developed in this research is a novel polishing automation system for preventing the workers from being exposed to poor working environments. This robot is able to change multiple polishing tools automatically; however, the workers can conveniently replace the worn-out polishing pads with new ones. The mobile platform of the polishing robot employs omnidirectional wheels to enable a flexible motion even in small and complicated workspaces. To evaluate the performance of the developed concrete polishing robot, extensive experiments including square trajectory tracking, automatic tool changing, actual polishing, and path generation simulation were performed.

THE ANATOMY OF PEDIATRIC LAPAROSCOPIC AND THORACOSCOPIC PROCEDURES ‐ NEWER CONCEPTS AND PROCEDURES

Laparoscopic procedures in pediatric surgery can be be divided grossly into abdominal and thoracic procedures. The basic procedures in laparoscopy require an understanding of body wall surface and muscle anatomy. Laparoscopic pediatric procedures have revolutionized the treatment of tracheo‐oesophageal fistulas with oesophageal atresia, duodenal atresia, anorectal malformations, appendicitis, hirschsrpung disease and inguinal hernias.Abdominal laparoscopy requires gas insufflation, the use of surface ports in various sites and and a keen understanding of upper and lower abdominal anatomy. Iatrogenic abdominal injuries include vascular trauma, retroperitoneal heamorrhage, bladder injuries and stomach injuries especially when it is overinflated. Most procedures use a camera port with 2 or more ports for instrumentation. Lower abdominal laparoscopies have a risk of hernias, damage to the inferior epigastric blood vessels and bowel damage. A detailed knowledge of the abdominal body wall musculature and underlying vascular structures is required. The anatomy reinforcing single port laparoscopy procedures is presented in this work too. Transuterine and cul‐de‐sac approaches are revisited and explained.Thoracospic pediatric surgical procedures have a risk of injury to the lung, pleura and thoracic wall vasculature. Newer anatomical approaches through the posterior thoracic wall ports are also proposed and explained.To correct spinal and vertebral defects newer sites of laparoscopic port entry are proposed with an eye to access and maximum utilization of small working space in such procedures.Support or Funding InformationFunding received from the Ministry of Health, Saudi Arabia and the Indian Institute of Morphology, Kolkata.

Dealing with Magnetic Disturbances in Human Motion Capture: A Survey of Techniques.

Magnetic-Inertial Measurement Units (MIMUs) based on microelectromechanical (MEMS) technologies are widespread in contexts such as human motion tracking. Although they present several advantages (lightweight, size, cost), their orientation estimation accuracy might be poor. Indoor magnetic disturbances represent one of the limiting factors for their accuracy, and, therefore, a variety of work was done to characterize and compensate them. In this paper, the main compensation strategies included within Kalman-based orientation estimators are surveyed and classified according to which degrees of freedom are affected by the magnetic data and to the magnetic disturbance rejection methods implemented. By selecting a representative method from each category, four algorithms were obtained and compared in two different magnetic environments: (1) small workspace with an active magnetic source; (2) large workspace without active magnetic sources. A wrist-worn MIMU was used to acquire data from a healthy subject, whereas a stereophotogrammetric system was adopted to obtain ground-truth data. The results suggested that the model-based approaches represent the best compromise between the two testbeds. This is particularly true when the magnetic data are prevented to affect the estimation of the angles with respect to the vertical direction.

Pediatric Robot-Assisted Laparoscopic Pyeloplasty.

The laparoscopic approach to the pyeloplasty procedure has proven to be safe and effective in the pediatric population. Multiple studies have revealed outcomes comparable to the open approach. However, a major drawback to laparoscopy is the technical challenge of precise suturing in the small working space in children. The advantages of robotic surgery when compared to conventional laparoscopy have been well established and include motion scaling, enhanced magnification, 3-dimensional stereoscopic vision, and improved instrument dexterity. As a result, surgeons with limited laparoscopic experience are able to more readily acquire robotic surgical skills. Limitations of the robotic platform include its high costs for acquisition and maintenance, as well as the need for additional robotic surgical training. In this article, we review the current status of the robot-assisted laparoscopic pyeloplasty, including a brief history, comparative outcomes, cost considerations, and training.