Analysis of Eye Tracking Data to Measure Situational Awareness in Offshore Drilling Operations

In complex, high-stakes tasks such as offshore oil and gas drilling where substantial number of monitoring parameters involve in the operation, the analyses of human operator’s situational awareness (or situation awareness, SA) become more important to avoid severe incidents initiated by the poor cognitive performance. Numerous SA measurement practices have been proposed in the previous researches, however, most of them employed the verbal and behavioral response analyses which are subjective to the researchers’ notions. In this study, an integrated approach combining subjective measures (e.g. verbal responses) with physiological metrics (e.g. eye fixation data) was investigated to seek the benefits for SA analyses in the field of offshore oil and gas drilling. A pre-existing incident based experimental test in a high-fidelity simulator facility was designed for real-time log indicators monitoring tasks, and a set of eye tracking devices collected verbal responses and oculomotor information simultaneously during the real-time tasks. To quantify the verbal responses, scoring metrics were newly developed for this study. The metrics assigned the points to the participants’ verbal responses based on their uttered keywords (abnormal, kick or blow-out) reacting to the situation. Quantitative statistical analyses were applied to ocular observations and verbal response scores collected from the predesigned Areas of Interests (AOIs) on the monitoring screen, using one-way ANOVA and Friedman test, respectively. The analyses provided unique and complementary insights that mapped the measures from both metrics to the level of situation awareness and that helped understand the cognitive process in time critical decision-making tasks in offshore oil and gas field. In addition to the statistical investigation, data mining approach using time series clustering technique was introduced to group the participants’ scanning pattern with respect to the temporal sequences, and to find the correlation of the scanning pattern to the quantified situation awareness. According to the analysis results, the expertise of the participants affected on their cognitive mechanisms to identify and respond to the situations to some extent. The content and timing of the situation also served as one of the important factors to determine the level of situation awareness. The participants’ scan patterns were clustered into four groups and suggested a potential correlation between the visual scanning pattern and the quantified situation awareness (i.e. verbal response scores). It was found that the vertical attending tendencies to the individual logs might lead a higher comprehension of the situation than the horizontally transitional attending tendencies between different logs

SULFIDE STRESS CRACKING BEHAVIOR OF GRADE C-110, Q-125 AND T-95 STEEL TUBULARS UNDER HIGH-PRESSURE CONDITIONS

Due to the expansion of hydrocarbon exploration into challenging sour oil and gas resources, the industry is now facing severe sour related corrosion problem. Sulfide Stress Cracking (SSC) is one of the detrimental types of corrosion which happens in sour environment. SSC quickly diminishes performance of downhole tubulars. The embrittlement induced by SSC causes failure of steel at a stress level, which is significantly lower than its yield strength. A premature failure of downhole tubulars impacts safety and operational issues during drilling, completion and production phases. Therefore, it is necessary to study the failure behavior of carbon steels used in sour environment. The principal aim of this study is to understand mechanisms of SSC in the presence of CO2 and experimentally investigate the failure characteristics of API steels (T-95, C-110 and Q-125) exposed to high-pressure sour environment while subjected to a tensile load. Hence, to carry out the experimental investigation, minipipe specimens were cut and manufactured from API grade tubulars. During the test, a specimen was place in a SSC test cell (high-pressure autoclave), which was partially filled with 2% NaCl solution saturated with mixed gas containing CH4, CO2 and H2S. In the cell, the specimen was strained to create stress level, which is equal to 80% of its yield strength while maintaining the desired CH4, CO2 and H2S partial pressures for seven days to simulate the corrosive environment. The total pressure inside the specimen was kept at 6,000 psi while the outer pressure was held at 4,000 psi. Impact of CO2 content of the gas phase on SSC is examined varying CO2 concentration (i.e. ratio of partial pressure of CO2 to the total pressure) from 0 to 40%. All tests were conducted at constant temperature (100°F) and H2S concentration (300 ppm). Temperature of 100°F is chosen for the CO2 investigation because SSC is known to occur at low temperature causing considerable change in mechanical properties of steel. Mechanical property changes occurring after exposure to the corrosive environment is used to quantify embrittlement of test specimens. Hence, mechanical properties of the specimens were measured after the exposure using Tensile Strength Testing (TST) apparatus and compared to the initial mechanical properties of an uncorroded clean specimen (baseline). After strength testing, microscopic examination was performed on broken specimens to assess embrittlement of the specimens based on crack features and shear deformation pattern. According to the experimental results, SSC susceptibility of T-95 and C-110 grade steels is maximized at about 10% CO2 while that of Q-125 grade maximized at 25% CO2. The experiment reveals that tested carbon steels are safe to use without SSC concerns in environment containing H2S content of up to 300 ppm which is equivalent to 1.8 psi at total pressure of 6000 psi. However, presence of CO2 in sour environment significantly reduces the SSC resistance of steel especially when CO2 concentration is in the range of 10 to 30%

Practical License Plate Recognition in Unconstrained Surveillance Systems with Adversarial Super-Resolution

Although most current license plate (LP) recognition applications have been significantly advanced, they are still limited to ideal environments where training data are carefully annotated with constrained scenes. In this paper, we propose a novel license plate recognition method to handle unconstrained real world traffic scenes. To overcome these difficulties, we use adversarial super-resolution (SR), and one-stage character segmentation and recognition. Combined with a deep convolutional network based on VGG-net, our method provides simple but reasonable training procedure. Moreover, we introduce GIST-LP, a challenging LP dataset where image samples are effectively collected from unconstrained surveillance scenes. Experimental results on AOLP and GIST-LP dataset illustrate that our method, without any scene-specific adaptation, outperforms current LP recognition approaches in accuracy and provides visual enhancement in our SR results that are easier to understand than original data.Comment: Accepted at VISAPP, 201

An eye tracking based framework for safety improvement of offshore operations

Offshore drilling operations consist of complex and high-risk processes. Lack of situational awareness in drilling operations has become an important human factor issue that causes safety accidents. Prolonged work shifts and fatigue are some of the crucial issues that impact performance. Eye tracking technology can be used to distinguish the degree of awareness or alertness of participants that might be related to fatigue or onsite distractions. Oculomotor activity can be used to obtain visual cues that can quantify the drilling operators’ situational awareness that might enable us to develop warning alarms to alert the driller. Such systems can help reduce accidents and save non-productive time. In this paper, eye movement characteristics were investigated to differentiate the situational awareness between a representative expert and a group of novices using a scenario-based Virtual Reality Drilling Simulator. Significant visual oculomotor activity differences were identified between the expert and the novices that indicate an eye-tracking based system can detect the distraction and alertness exhibited by the workers. Results show promise on developing a framework which implements a real-time eye tracking technology in various drilling operations at drilling rigs and Real Time Operation Centers to improve process safety

The Role of Confined Water in Ionic Liquid Electrolytes for Dye-Sensitized Solar Cells

Ionic liquids (ILs) provide an attractive medium for various chemical and redox reactions, where they are generally regarded as hydrophobic. However, Seddon et al. discovered that 4–10 wt % water absorbs into ILs that contain bulky anions, and Cammarata et al. found that the molecular state of water in ILs is dramatically different from that of bulk liquid water or that of water vapor. To determine the microstructure of water incorporated into ILs and the impact on properties, we carried out first-principles-based molecular dynamics simulations. We find water in three distinct phases depending on water content, and that the transport properties depend on the nature of the water phases. These results suggest that the optimal water content is ~10% mole fraction of water molecules (~1.1 wt %) for applications such as nonvolatile electrolytes for dye-sensitized solar cells (DSSCs). This suggests a strategy for improving the performance of IL DSSC by replacing water with additives that would play the same role as water (since too much water can deteriorate performance at the anode–dye interface)

Rapid Dye Regeneration Mechanism of Dye-Sensitized Solar Cells

During the light-harvesting process of dye-sensitized solar cells (DSSCs), the hole localized on the dye after the charge separation yields an oxidized dye, D^+. The fast regeneration of D^+ using the redox pair (typically the I^–/I_(3)^– couple) is critical for the efficient DSSCs. However, the kinetic processes of dye regeneration remain uncertain, still promoting vigorous debates. Here, we use molecular dynamics simulations to determine that the inner-sphere electron-transfer pathway provides a rapid dye regeneration route of ∼4 ps, where penetration of I^− next to D^+ enables an immediate electron transfer, forming a kinetic barrier. This explains the recently reported ultrafast dye regeneration rate of a few picoseconds determined experimentally. We expect that our MD based comprehensive understanding of the dye regeneration mechanism will provide a helpful guideline in designing TiO_2−dye−electrolyte interfacial systems for better performing DSSCs

Gate tunable optical absorption and band structure of twisted bilayer graphene

We report the infrared transmission measurement on electrically gated twisted bilayer graphene. The optical absorption spectrum clearly manifests the dramatic changes such as the splitting of inter-linear-band absorption step, the shift of inter-van Hove singularity transition peak, and the emergence of very strong intra-valence (intra-conduction) band transition. These anomalous optical behaviors demonstrate consistently the non-rigid band structure modification created by the ion-gel gating through the layer-dependent Coulomb screening. We propose that this screening-driven band modification is an universal phenomenon that persists to other bilayer crystals in general, establishing the electrical gating as a versatile technique to engineer the band structures and to create new types of optical absorptions that can be exploited in electro-optical device application.Comment: 13 pages, 4 figure