· · · Institutional Repository

This is the report for our Bachelor project (IN3405). We did an internship at Centric and made a simulator to visualise their concept "Mobile Hubs and Smart Connected Containers".

Within the Dow Chemical Company the strategy is to centre process flowsheet design activities around the simulation tool Aspen Plus (from Aspen Tech Inc.). However, the model library of Aspen Plus is limited in type and number of models of process unit operations. Equation oriented modelling tools, such as gPROMS (from Process Systems Enterprise Ltd.) or Aspen Custom Modeler – ACM (from Aspen Tech Inc.), can be used to develop custom models of process unit operations which are not available in the Aspen Plus model library. For consistent flowsheet simulation and optimization it is required that these custom models can be exported to and used within Aspen Plus, just like any other model already available in the Aspen Plus model library. Recently, interfaces – based on the CAPE-OPEN standards - have been implemented in the latest releases of the above mentioned process simulation tools. To test the status and performance of the software interoperability, as well as to examine the custom model performance in Aspen Plus, a model of a gas separation membrane unit is developed in gPROMS and in ACM and exported for use in Aspen Plus. This thesis describes the achievements made in the development of the custom membrane model and its interfacing with Aspen Plus. Also, an improved method for model initialisation is presented. Model initialisation is one of the principal obstacles for the development of generic custom models, i.e. models which can run successfully irrespective of the set of components, physical property method, or range of operating conditions. The main conclusions from this study are that several software features enhance the development of generic and robust custom models in equation oriented modelling tools, such as a hierarchical model structure, the usage of an external physical property package, as well as the incorporation of a model initialisation structure (e.g. like the one proposed in this thesis). Moreover, the current functionality and performance of the interfaces for custom models between gPROMS and ACM on one side – and Aspen Plus on the other side – are not sufficient to be used for industrial practice. They need to be improved significantly by the software vendors.

The advanced technology of today has reduced the need of testing medical equipment on human patients. The invention of the lung simulator has made it possible to test ventilators without putting the condition of test patients in jeopardy. The device also allows medical staff to be trained in a safe and more rapid way. Several types of lung simulators are available. The digitally controlled variant is the most versatile one for simulations. This type has easily adjustable static and dynamic properties, which, in contrary to traditional passive mechanical simulators, make it possible to simulate different types of breathing. The available design of a digitally controlled lung simulator, however, has one major drawback. The system uses a motor-ball screw assembly to drive a piston in the air compartment. One of the properties of this assembly is that the motor shaft motion is negligibly affected (not ‘backdrivable’) by air pressure exerted on the piston by an external source. The result of this is a feedback system that needs to realize the entire dynamic response to pressure changes, by active control of the motor. Because of this, the system can easily become unstable for certain settings of the static and dynamic properties. The objective of this thesis is to determine what the best alternative actuator is for the lung simulator, to the end of making it more stable than the current version. By improving the existing lung simulator and improving its range of operation, and its performance, it can be made more effective and accurate, which will result in better healthcare. To reach this goal, firstly the desired requirements for the lung simulator will be obtained from the end user. After this, a literature study about alternative actuators shall be conducted. With the results of the literature study, a ranking of the alternative actuators are determined. From the literature study eight alternative actuators have come up. These are the moving coil actuator, moving iron actuator, permanent magnet synchronous motor (PMSM), ironless core motor, piezoelectric actuator, pneumatic actuator, hydraulic actuator and wax motor. The most important requirements on which the different actuators are evaluated are backdrivability, force linearity, force, precision, speed and stroke length. Of the eight alternative actuators, except for the PMSM and the ironless core actuator, all the others have an insufficient score on one or more of the requirements. A comparison of the PMSM and the ironless core actuator shows that the backdrivability of the ironless core actuator is better, and that it has the best overall score. The conclusion is that the ironless core actuator is the most suitable alternative for the lung simulator. The use of the actuator should increase the stability of the lung simulator. However, no testing was possible because of malfunctioning hardware and time shortage. Therefore no practical confirmation could be obtained about the effects of the new actuator on the system. It is recommended to put the top-ranked actuators to the test in a prototype. From the test results it will be possible to confirm whether the instability of the original lung simulator was indeed caused by the actuator, and whether the ironless core motor is indeed the best suitable alternative actuator for the lung simulator.

It is suspected that instability problems in the current generation of lung simulators are caused by its actuator, a brushless DC motor, in combination with the system configuration. The hypothesis is that these problems can be resolved by replacing the actuator with a backdrivable actuator (that is, an actuator that responds well to external force) in a new system. In this BSc Thesis this hypothesis is researched. The backdrivable actuator (in this particular case, a Voice Coil actuator) in a new system can overcome the instability problems.

In the Netherlands most people have mastered riding a bicycle. Usually at the age of 4 a child learns to ride a bicycle. Few people however know how a bicycle actually works. A bicycle is a dynamic system that is more complex than one would expect. For example in order to go through a left curve on a bicycle one first has to steer right for a short period of time in order to make the bicycle lean to the left. This effect is called: "countersteering". While going through the left curve one needs to apply torque to the handlebars but not in the direction of the curve. The torque that is applied to the handlebars is to the right and it prevents the handlebars from rotating even further. The bicycle as a dynamical system is described in the article "Linearized dynamics equations for the balance and steer of a bicycle: a benchmark and review" [1] written by J. P. Meijaard, Jim M. Papadopoulos, Andy Ruina and A. L. Schwab in 2007.

Epidural anaesthesia is a pain relief technique commonly performed on patients in labor. It requires insertion of a needle into patients back into the epidural space of the spine and inject anaesthetic. It is a blind procedure and anaesthesiologists rely only on the forces felt during needle insertion to determine the position of the needle tip. It is a complex procedure that requires training. However, in a majority of hospitals the residents are trained on patiets. In this thesis development and validation of a new epidural needle insertion simulator with haptic feedback is discussed. . The simulator has 1DOF for needle insertion and 1DOF for needle orientation. The simulator uses a cable-pulley mechanism to transmit forces to the needle. The simulator provides active force-feedback by means of a motor in the needle insertion direction and passive force-feedback by means of a brake in the needle orientation direction. The simulator simulates needle-tissue and needle-bone interaction forces. It also incorporates simulation of different virtual patients, which can be selected from the graphical user interface. The real-time position of the needle can be seen in the graphical user interface. The simulator is validated through experiments by expert anaesthesiologists and novices. The simulator is validated for face and constuct validity. The results were promising showing high acceptance rate with addition of some features. Moreover, difference in performance between experts and novices was found and thus evaluating similarity to a real scenario.

Current trends in computer architecture focus on multicore platforms. The target of these new platforms is to scale the performance of the system with the number of cores. However, the performance of current archictectures is limited due to thread-level parallelism overhead and programmability. StarSS is a task-based programming model that eases the programmability of multicores and tries to exploit functional parallelism within applications. However, the performance of StarSS does not scale efficiently for fine-grained tasks, as for such tasks the task management overhead becomes significant in comparison to the execution of the tasks. Nexus is a dynamic hardware support system that aims to alleviate the current overhead of StarSS, by offloading the dependency resolution process and the synchronization with the cores to hardware. In this work, we implement Nexus by defining and connecting the new hardware in a Cell archictecture simulator. The scalability, performance, and throughput of the implementation are evaluated for different task sizes and number of cores, using several dependency patterns. Furthermore, different configuration parameters are evaluated, such as the dimension of the new hardware inserted in the existing architecture. Results show a large improvement of the scalability offered by Nexus in comparison with StarSS, especially for fine-grained tasks. Nexus succeeds at alleviating the overhead of StarSS by accelerating the dependency resolution process and the synchronization with the worker cores. Furthermore, the evaluation of the Nexus system dimensions has shown that its scalability decreases slightly with its area.

Objectives The main objectives of this study were to establish expert validity (a convincing realistic representation of colonoscopy according to experts) and construct validity (the ability to discriminate between different levels of expertise) of the Simbionix GI Mentor II virtual reality (VR) simulator for colonoscopy tasks, and to assess the didactic value of the simulator, as judged by experts. Methods Four groups were selected to perform one hand–eye coordination task (EndoBubble level 1) and two virtual colonoscopy simulations on the simulator; the levels were: novices (no endoscopy experience), intermediate experienced (<200 colonoscopies performed before), experienced (200–1,000 colonoscopies performed before), and experts (>1,000 colonoscopies performed before). All participants filled out a questionnaire about previous experience in flexible endoscopy and appreciation of the realism of the colonoscopy simulations. The average time to reach the cecum was defined as one of the main test parameters as well as the number of times view of the lumen was lost. Results Novices (N = 35) reached the cecum in an average time of 29:57 (min:sec), intermediate experienced (N = 15) in 5:45, experienced (N = 20) in 4:19 and experts (N = 35) in 4:56. Novices lost view of the lumen significantly more often compared to the other groups, and the EndoBubble task was also completed significantly faster with increasing experience (Kruskal Wallis Test, p < 0.001). The group of expert endoscopists rated the colonoscopy simulation as 2.95 on a four-point scale for overall realism. Expert opinion was that the GI Mentor II simulator should be included in the training of novice endoscopists (3.51). Conclusion In this study we have demonstrated that the GI Mentor II simulator offers a convincing realistic representation of colonoscopy according to experts (expert validity) and that the simulator can discriminate between different levels of expertise (construct validity) in colonoscopy. According to experts the simulator should be implemented in the training programme of novice endoscopists.

The phenomenon of wave overtopping during storms was simulated by the Wave Overtopping Simulator on a 1/15 grass covered slope. The four 'Wave Overtopping Simulator' tests were done within the framework of the Research project 'Super sea dike with high safety level and environmental friendly' funded by Viet Nam government. The main objective of these tests was to test the resistance of the gentle slope (steepness of 1/15) protected with local grass against wave overtopping with the Wave Overtopping Simulator. The super dike model was built up at the outdoor laboratory of the Viet Nam academy for water resources, in Yen Binh ward, Thach That district, Ha Noi. In June 2012, the super dike slope covered with one year grass mat was tested with the simulator. The front velocity of overtopping flows were estimated at three positions along the slope using digital camcorders. In general, increasing volume generates higher front velocity and it is likely to become larger downward the slope. Under attack of overtopping flows generated by the simulator, the super dike slope covered with Bermuda and Carpet grass was damaged moderately. Damage was in the form of a shallow erosion which took place around the dike crest and toe (geometric transitions). The mechanism is defined as 'roll up' or 'turf set-off', the grass mat of about 5 to 7 cm thick is lifted and rolled up gradually to expose the underneath soil body. Small damaged spots were observed around two obstacles of YB1 and YB4 sections therefore, influence of these objects on slope performance was unclear. Man-made eroded spots were introduced at two positions on YB3 slope by removing the grass turf which was about 10 cm thick of the top layer including most of roots. Applying discharges of 40, 60, 80 and 100 l/s per m with a wave height of 2.0 m caused a gradual extension of the artificial damage downward while depths and widths remained the same. Apparently, the destructive impact of overtopping flow is most effective in its direction, from crest to toe. The super dike slope was 1/15 of inclination and protected by two local grass species, Bermuda and Carpet. When being tested, the grass mats were about one year old. The maximum discharge of the simulator 100 l/s per m was applied for 6 to 10 hours, thus resulting in moderate damage to the grass cover. These damaged spots were limited within 7 to 10 cm under the slope surface and insufficiently significant that might threaten the function of the super dike. The simulator was designed to test the normal sea (river) dike slopes with a steepness of 1/3 to 1/6 under a mild wave condition, significant wave heights not above 2.0 m. Therefore, to assess the super dike slope which is unbreachable even in extreme condition, a device with much higher capacity is clearly required.

The drinking water treatment industry is becoming increasingly centralized and automated. This requires a different operator training approach then the traditional on the job training. To address this requirement a drinking water treatment plant simulator was developed. A major advantage of such a simulator might be that the normally very slow process can be accelerated, giving an increase in feedback to the trainees. In this paper the effectiveness of training on an accelerated simulated process is investigated. Four groups of subjects were trained on the Waterspot Simulator, three groups (of various experience) trained at 60x accelerated simulation speed, and one group trained at real-time simulation speed. The results showed that the Waterspot Simulator could distinguish between experienced operators and laymen and that the groups that trained with 60x accelerated simulation speed outperformed the group that trained at real-time, when they were compared ona real-time quasi transfer of training task.

The demand for high quality care is in contrast to reduced training time for residents to develop arthroscopic skills. Thereto, simulators are introduced to train skills away from the operating room. In our clinic, a physical simulation environment to Practice Arthroscopic Surgical Skills for Perfect Operative Real-life Treatment (PASSPORT) is being developed. The PASSPORT concept consists of maintaining the normal arthroscopic equipment, replacing the human knee joint by a phantom, and integrating registration devices to provide performance feedback. The first prototype of the knee phantom allows inspection, treatment of menisci, irrigation, and limb stressing. PASSPORT was evaluated for face and construct validity. Construct validity was assessed by measuring the performance of two groups with different levels of arthroscopic experience (20 surgeons and 8 residents). Participants performed a navigation task five times on PASSPORT. Task times were recorded. Face validity was assessed by completion of a short questionnaire on the participants’ impressions and comments for improvements. Construct validity was demonstrated as the surgeons (median task time 19.7 s [8.0–37.6]) were more efficient than the residents (55.2 s [27.9–96.6]) in task completion for each repetition (Mann–Whitney U test, P < 0.05). The prototype of the knee phantom sufficiently imitated limb outer appearance (79%), portal resistance (82%), and arthroscopic view (81%). Improvements are required for the stressing device and the material of cruciate ligaments. Our physical simulation environment (PASSPORT) demonstrates its potential to evolve as a training modality. In future, automated performance feedback is aimed for.

Rational An increasing number of fatal road-accidents have been reported in which ecstasy was found in the blood of drivers. Although, ecstasy is frequently found to have been used in combination with alcohol, studies on the acute effects of ecstasy co-administered with alcohol on driving performance are relatively rare. Objective The present study was designed to establish the extent of driver impairment as a consequence of ecstasy or combined ecstasy and alcohol use as compared to driving under the influence of 0.3‰, 0.5‰ and 0.8‰ alcohol. Furthermore, subjective performance was also assessed. Results Alcohol and ecstasy mainly influenced automated driving performance such as lateral and speed control. However, small to no effects of the substances were found on more complex driving behaviour. Overall, variance within the different driving measures was high especially when participants were treated with 3.4-methylenedioxy-methamphetamine (MDMA) and alcohol. Furthermore, equivalence testing showed that combined use may lead to impaired driving for some, but not all, drivers. Participants rated their own performance to be slightly worse than normal in both studies. Since driving was actually seriously deteriorated, this was a falsely positive assessment of their condition. Conclusions The dissociation between subjective perceptions and objective performance decrements are important notions for traffic safety since this may affect a driver’s judgement of whether or not it is safe to drive. For example, an intoxicated individual might decide to drive because the feelings of alertness caused by MDMA cloud the impairing effects of other drugs such as alcohol, thereby creating a potentially serious risk for traffic safety.

An enterprise resource planning (ERP) system is a comprehensive set of integrated software solutions. It is used for example to allow companies to improve their performance by streamlining business processes and to manage the companies’ resources. An ERP system incorporates a central database that supports the various functions of a company by drawing and feeding data to the applications used within the different departments so that the information is integrated throughout the business. ERP implementations are costly and the reason for why companies are willing to spend considerable money on such an endeavor is because they have been associated with benefits that make it worth it. The problem is that the benefits that justify the cost of implementing such a system are often not realized to their potential. That might render the cost associated with the implementation to outweigh the benefits and not the other way around as it should have been. In order to get the most out of the implementation, so at least the benefits outweigh the cost, it is crucial to carry out the implementation process successfully. That means by overcoming the challenges that are manifested not only in the complicated technical rollout and installing of the system but also in the reconfiguration of the organization in terms of its business processes and its structure so that the system fits with the organization. Furthermore, as this leads an organizational change as well as an adoption of a new information system which impose great changes on employees, there is also the challenge to facilitate the transition in order to mitigate the effects of resistance to change. Most companies rely on external consultants to transfer their accumulated knowledge of ERP implementations to their employees to facilitate in-house contribution to successful implementations. This study is carried out for the company Accenture that commonly takes on the role for providing such consultancy. It is carried out in order to develop a product that can assist with getting the knowledge transfer across not only in sessions with clients of Accenture but also for in-house education. Driven by above mentioned motive this study sets out to develop an interactive model that can be used in a gaming session that simulates the process of implementing an ERP system. This model provides a formal system that captures the essence of the systematic challenge of the natural system of ERP implementations in terms of realizing the associated benefits. Here interactive means that it is allowed for multiple inputs (levers) which can be tweaked by users so that they can interact with the formal system in a way that mimics how the natural system is interacted with in reality. Through the interaction with the model the users should experience the systematic challenge of carrying out the implementation process, which brings up one of the purposes of the model. The other purpose is to provide a medium for discussion, as the model is interacted with by several persons (at once) in a group session. The aim of such discussions is to facilitate a common understanding (e.g. between consultants and clients or people from different departments) on the overall process. The interactive model was formulated and supplied with an interface aimed for usability in terms of allowing for game-like experience of going through a simulated process of an ERP implementation. This forms the product of this study which can be summarized as a prototype of a management flight simulator on the process of implementing an ERP system. The model is based on the methodology of system dynamics and the study looks also towards the field of serious gaming as the product is intended for gaming purposes. In order to realize this product so that it meets the purposes stated above the following research questions were stated and answered as follows: 1. When looking at ERP implementations in general, what is the systematic challenge that commonly needs to be overcome so the benefits of the implementation can be realized? 2. What is the best way to represent the process of ERP implementations, what are the foreseen challenges for transforming that representation to a simulation model and what are the implications of the approach taken (for this case and in general)? 3. What is the potential of the product of this study to deliver its purpose? The decision for implementing an ERP system should not be based purely on the benefits that have been generally associated with the technology but on a strategy that identifies if they apply to the organization. A benefit hierarchy was formulated in this study that traces not just what the benefits of ERP implementations are but what constitutes them. The implementation should be justified based on how the specific constituting elements of the benefits fit to solve identified problems or lead to identified opportunities. If this is clear then the systematic challenge remains to carry out the implementation by balancing the resources available for the project between four aspects that commonly need to be aligned in order for the ERP implementations to be successful. These are the aspects of technology, business processes, organizational structure and people. The level of detail for representing the activities of these four common aspects needed to be quite high in order for the challenge to be captured, of balancing resources between the aspects (and the activities within them) while making sure that the aspects are aligned. A design choice was therefore made to represent the activities in terms of what drives them which is reasonably the resource allocation to the activities. All phases of an implementation, from analysis until after the go live, were decided to be included in the simulation. From this and the level of detail for activities a modeling challenge was foreseen due to the great many activities to be included dynamically. Conceptual maps of how the activities relate to each other in terms of dependencies were first constructed in order to model the process of the activities that should be carried out in terms of their effects and dependencies. These conceptual maps were then validated with expert interviews and what remained was to transform them to a simulation model. To make this transformation feasible an approach was taken to use molecules of structures to represent the activities in general. What is meant with that is that the activities are represented by general structures that can be used repeatedly to incorporate all activities in the simulation so that they are represented dynamically. Only two types of molecule structures were needed to allow for each activity to be captured. The dynamic feedback governed behavior of the model of this study is mostly based on the model’s base structure. This base structure is the result of improving upon a pre-existing model of which the model of this study builds upon. The inputs for how this behavior will result are the outputs of the streams of activities that make up the implementation process. These streams of activities were formed by stringing together the molecules that represent the individual activities. The individual molecules are governed by a limiting feedback loop and their behavior is therefore logically characterized by an asymptotic growth of completing an activity. The behavior of entire streams of activities is therefore a combination of the activities being performed where output of activities influence the effectiveness of attaining the completeness of the asymptotic growth of other activities until it has an effect on the base structure. The management flight simulator (the product of this study) allows users to play integral part in the simulation of the ERP implementation process that the model provides for. The users travel through the streams of activities mentioned above by making sure that individual activities are performed by allocating resources to them. It is completely up to the users how they move through the process in terms of when, how much and for how long they allocate resources to the individual activities. Logically, though, the path of direction is from the analysis phase to the deploy phase by moving through the phases of design, build and test. For each of these phases the users allocate resources to the aspects and then further divide that allocation to the individual activities within them. They should try to carry out the implementation by staying within the given planned budget and to make sure that the system can be set to go live on time. If necessary the users can delay the go live point. Since the molecule structures are general they can be used in any other situation where the focus is on the rate performing the activity as driven by some input rather than how the activity is performed; where this input, such as resource allocation, is the main force driving the activity’s rate of completeness or increase in output quality. The use of the molecules is especially relevant if an activity dense process is to be modeled and simulated interactively. What would then set apart the models for the different type of projects would be the interconnections between the activities, the relative difference of the effort needed for them and there would always be some structure of which is influenced by the activities but a separate structure in itself. The evaluation of the product conducted in this thesis provides promising indications for the usability of the product in terms of fulfilling its two purposes mentioned above. Yet this is only an indication, a sneak preview, for the potential usability and usefulness. That is why this is merely a preliminary evaluation and that a more thorough face evaluation and tests for usability are needed. The criteria that the promising indication of the preliminary evaluation is based on is that the questions about the potential for the product to deliver its intended purpose received positive and affirmative answers in two feedback sessions conducted. The preliminary evaluation of the product conducted in this thesis only gives indication that the potential usability is good. What is lacking in this thesis, due to time restrictions, is that the product still needs to be tested directly for its usability. To say if the product actually delivers its purpose would require a testing of it in sessions with people, who are potential users and would play through the simulation.

The aim of this study is to develop new interpretation methods and overall risk assessment models for navigation aspects in association with waterway design. The methods, which are based on the results achieved from ship maneuvering simulation and numerical models, address two ship accident scenarios (i.e. grounding or collision with fixed objects) in terms of the occurrence probability of such accidents. The final results derived from risk assessment are straightforwardly used in the optimal design of waterway dimensions. Several important procedures pertaining to the application of design tools and techniques for such purposes have also been discussed.

Simulation fidelity is an intrinsic element of any simulation system, one that all its developers and users have to deal with one way or the other. It is commonly recognized by the modeling and simulation community that simulation fidelity is an essential vehicle in properly assessing the validity and credibility of simulation results. Furthermore, fidelity is one of the main cost-drives of any model or simulation development. Rigorous assessment of fidelity is, however, one of the most difficult and hard to grasp issues within the model and simulation community. Substantial and exhaustive research endeavors in this area are very limited. Due to this, simulation fidelity still remains a hardly touched upon and rather uncultivated area. This thesis tries to fill this void by the analysis, extension and integration of existing simulation fidelity approaches into a single unified fidelity theory and practice. All this is done from a general simulation system life cycle perspective, not limited by any specific application or problem domain aspects. The foundation for this developed unified fidelity framework comprises a precise mathematical formulation for fidelity and the fundamental concepts underlying its characterization and measurement. The unified fidelity framework is completed with a fidelity management process model outlining a series of generic stages, activities and tasks, which together provide a structured but generic approach to properly integrate and apply all other unified fidelity framework elements in the simulation system development and validation process.

Visuo-spatial ability is associated with a quality of performance in a variety of surgical and medical skills. However, visuo-spatial ability is typically assessed using Visualization tests only, which led to an incomplete understanding of the involvement of visuo-spatial ability in these skills. To remedy this situation, the current study investigated the role of a broad range of visuo-spatial factors in colonoscopy simulator training. Fifteen medical trainees (no clinical experience in colonoscopy) participated in two psycho-metric test sessions to assess four visuo-spatial ability factors. Next, participants trained flexible endoscope manipulation, and navigation to the cecum on the GI Mentor II simulator, for four sessions within 1 week. Visualization, and to a lesser degree Spatial relations were the only visuo-spatial ability factors to correlate with colonoscopy simulator performance. Visualization additionally covaried with learning rate for time on task on both simulator tasks. High Visualization ability indicated faster exercise completion. Similar to other endoscopic procedures, performance in colonoscopy is positively associated with Visualization, a visuo-spatial ability factor characterized by the ability to mentally manipulate complex visuo-spatial stimuli. The complexity of the visuo-spatial mental transformations required to successfully perform colonoscopy is likely responsible for the challenging nature of this technique, and should inform training- and assessment design. Long term training studies, as well as studies investigating the nature of visuo-spatial complexity in this domain are needed to better understand the role of visuo-spatial ability in colonoscopy, and other endoscopic techniques.

Background. Surgeons perform complex tasks while exposed to multiple distracting sources that may increase stress in the operating room (e.g., music, conversation, and unadapted use of sophisticated technologies). This study aimed to examine whether such realistic social and technological distracting conditions may influence surgical performance. Methods. Twelve medical interns performed a laparoscopic cholecystectomy task with the Xitact LC 3.0 virtual reality simulator under distracting conditions (exposure to music, conversation, and nonoptimal handling of the laparoscope) versus nondistracting conditions (control condition) as part of a 2 x 2 within-subject experimental design. Results. Under distracting conditions, the medical interns showed a significant decline in task performance (overall task score, task errors, and operating time) and significantly increased levels of irritation toward both the assistant handling the laparoscope in a nonoptimal way and the sources of social distraction. Furthermore, individual differences in cognitive style (i.e., cognitive absorption and need for cognition) significantly influenced the levels of irritation experienced by the medical interns. Conclusion. The results suggest careful evaluation of the social and technological sources of distraction in the operation room to reduce irritation for the surgeon and provision of proper preclinical laparoscope navigation training to increase security for the patient.