Exploring the Multi-touch Interaction Design Space for 3D Virtual Objects to Support Procedural Training Tasks

Multi-touch interaction has the potential to be an important input method for realistic training in 3D environments. However, multi-touch interaction has not been explored much in 3D tasks, especially when trying to leverage realistic, real-world interaction paradigms. A systematic inquiry into what realistic gestures look like for 3D environments is required to understand how users translate real-world motions to multi-touch motions. Once those gestures are defined, it is important to see how we can leverage those gestures to enhance training tasks. In order to explore the interaction design space for 3D virtual objects, we began by conducting our first study exploring user-defined gestures. From this work we identified a taxonomy and design guidelines for 3D multi-touch gestures and how perspective view plays a role in the chosen gesture. We also identified a desire to use pressure on capacitive touch screens. Since the best way to implement pressure still required some investigation, our second study evaluated two different pressure estimation techniques in two different scenarios. Once we had a taxonomy of gestures we wanted to examine whether implementing these realistic multi-touch interactions in a training environment provided training benefits. Our third study compared multi-touch interaction to standard 2D mouse interaction and to actual physical training and found that multi-touch interaction performed better than 2D mouse and as well as physical training. This study showed us that multi-touch training using a realistic gesture set can perform as well as training on the actual apparatus. One limitation of the first training study was that the user had constrained perspective to allow for us to focus on isolating the gestures. Since users can change their perspective in a real life training scenario and therefore gain spatial knowledge of components, we wanted to see if allowing users to alter their perspective helped or hindered training. Our final study compared training with Unconstrained multi-touch interaction, Constrained multi-touch interaction, or training on the actual physical apparatus. Results show that the Unconstrained multi-touch interaction and the Physical groups had significantly better performance scores than the Constrained multi-touch interaction group, with no significant difference between the Unconstrained multi-touch and Physical groups. Our results demonstrate that allowing users more freedom to manipulate objects as they would in the real world benefits training. In addition to the research already performed, we propose several avenues for future research into the interaction design space for 3D virtual objects that we believe will be of value to researchers and designers of 3D multi-touch training environments

The impact of surface water-groundwater interactions on water quality in an urban stream

Stream restoration is a billion dollar business in the United States, and one of the processes restoration projects often try to improve is surface water-groundwater interaction. Groundwater is a key component of nutrient cycling, as it is where dissolved organic carbon and zones of anoxia can interact with the nitrate dissolved in the surface water. Groundwater also generally has greater total dissolved ions, as movement through pore space is many times slower than flowing surface water. Restoration projects that enhance surface water-groundwater interaction may help improve urban stream water quality. In an effort to decrease floods, many cities have physically altered streams to move water downstream as quickly as possible. Engineering projects result in straightened channels, armored banks with boulders or cement, incised channels, and removed riparian vegetation, sometimes even burying streams and making them part of storm sewer systems. This process, plus the large amount of impervious surface cover in cities, results in runoff going directly into streams, to be discharged downstream, instead of infiltrating to groundwater; this causes the streams to have flashy hydrographs and lowers baseflow. Many nonpoint source pollutants are discharged to urban streams, including heavy metals, pathogens, road salt, and nutrients. Urban planning is evolving and city planners now often recognize the importance of streams, even if just for aesthetic purposes, and when it is monetarily feasible, some cities are restoring urbanized streams to more natural designs. The goal of my research is to study how surface water-groundwater interactions, promoted by restoration practices, impact water quality in urban systems. The study site for this research is a first-order stream located in Syracuse, NY. Meadowbrook Creek emerges from a stormwater retention basin to flow 5.5 km downstream before discharging into the Erie Canal. There are two distinct reaches to the stream: the upper 4 km, which are heavily urbanized and flow along a bouldered, incised channel down the middle of a boulevard with no riparian vegetation. The most downstream 1.5 km, however, are more natural, with a meandering channel, established floodplain, and mature riparian vegetation. This dichotomy was used to investigate how effects of stream restoration, specifically reconnection of surface water to groundwater, impact surface water chemistry. I made bi-weekly longitudinal surveys of stream water chemistry in the creek from May 2012 until June 2013. Chloride concentrations in the upstream, urbanized reach were influenced by discharge of road salt during snow melt, peaking at 1440 mg/L. However, the natural, downstream reach had less temporal variation, only peaking at 1049 mg/L, due to buffering by lower chloride groundwater discharge. In the summer, there was little-to-no nitrate in the upper reach due to limited sources and high primary productivity, but concentrations reached over 1 mg N/L in the lower reach where riparian vegetation shade the stream. When temperatures fell below freezing, nitrate concentrations in the upper reach increased to 0.58 mg N/L, but were still lower than the natural reach, which averaged 0.88 mg N/L. Urban stream restoration projects that restore floodplain connection may impact water quality by storing high salinity road runoff during winter overbank events and discharging that water year-round, thereby attenuating seasonal fluctuations in chloride. Contrary to prior findings, we observed floodplain connection and riparian vegetation may alter nitrate sources and sinks such that nitrate concentrations increase longitudinally in connected urban streams downstream of disconnected reaches. I investigated the processes controlling chloride movement and storage in the lower floodplain further by building a 3D groundwater flow and solute transport model. The model was calibrated to hydraulic head across the floodplain and the observed baseflow groundwater discharge to the stream. The model was validated by comparing simulated chloride concentrations in the floodplain groundwater to observed field data. The main mechanism transporting chloride to the floodplain aquifer was winter overbank flood events during snowmelt or rain-on-snow precipitation, and flooding recharges floodplain groundwater directly. The model accurately predicts the maximum winter chloride concentration in the floodplain and the residence time of chloride as it is slowly released to surface water. Restoration projects that promote overbank flooding in winter have the potential to mitigate the negative ecosystem impacts of road salt in areas with high chloride contamination by temporarily storing chloride in groundwater, buffering surface water concentrations, and minimizing first-flush concentrations following periods of road salting. Finally, I investigated the sources and sinks of nitrate in the stream to evaluate what impact restoration may have on nutrient cycling. Altered channel morphology in urban streams changes the relative importance of nutrient sinks throughout the year, limiting denitrification and promoting assimilation. Nitrate injection tests and isotopic analysis of nitrate were performed to identify sources and sinks throughout the year, along with indirect measures of autotrophic uptake. The main source of nitrate to the system appears to be leaky sewers, as shown by the nitrate isotopes and fluoride concentrations, with a potential soil nitrogen signal as well. The urban reach has little-to-no nitrate in the spring through fall due to autotrophic uptake by filamentous green algae, as indicated by measurements of uptake properties along with measures of canopy density and algae mats. When temperatures decrease in the winter, autotrophic uptake shuts off and nitrate concentrations increase. The downstream, natural reach has high nitrate concentrations throughout the year, as the assimilation sink is minimized due to riparian shading. Nitrate isotopes do not indicate denitrification despite the surface water-groundwater interaction between the stream and floodplain. Uptake will lower nitrate concentrations for a large portion of the year, but restoration efforts that promote denitrification through increased dissolved organic carbon and increased hydrologic residence time may allow for permanent removal

Vulnerability analysis of hydrological infrastructure to flooding in coastal cities - a graph theory approach

Hydrological infrastructure such as pumps and floodgates are invaluable assets for mitigating flooding in coastal cities. These infrastructure components are often vulnerable to damage or failure due to the impact of flood waters, thus exacerbating the flood hazards and causing significant loss of life and destruction to property worth billions of dollars. Hence, there is a growing need worldwide to enhance the understanding of flood vulnerability and to develop key metrics for assessing it. This study proposes an approach for measuring the vulnerability of hydrological infrastructure to flood damage in coastal cities. In this approach, a hydrological infrastructure flood vulnerability index (HIFVI) is developed based on exposure, sensitivity and resilience of infrastructure assets to flooding. A graph-theoretic algorithm for implementing the proposed HIFVI is presented and applied to assess the flood vulnerability of floodgates in one of the most representative coastal cities - Jakarta, Indonesia. The application involves the construction of a graph-based spatio-topological network model of Jakarta\u27s hydrological system, with floodgates represented as network nodes and waterways as edges. An analysis of the constructed network is carried out based on the underlying graph-theoretic algorithm to compute HIFVI for all nodes that represent floodgates. The results show that HIFVI can point to the most vulnerable hydrological infrastructure components and also highlight locations within coastal cities where additional infrastructure are required to improve resilience to flooding. These information are vital to decision makers when planning and prioritising infrastructure maintenance and resource allocation for flood preparedness in coastal cities

Assessing the vulnerability of pumping stations to trash blockage in coastal mega-cities of developing nations

Pumping stations are important flood mitigation infrastructure used in coastal cities to remove accumulating floodwater from low-lying areas, where drainage is naturally poor due to very low slope gradient. In coastal mega-cities situated in developing nations, these pumping stations are often vulnerable to trash blockage as a result of frequent dumping of solid waste in water bodies. Given that blocked pumps are common causes of drainage infrastructure failure, the inability to identify the most vulnerable pumping stations can lead to inefficient allocation of limited resources for preventative maintenance of the drainage system. This study proposes an approach for measuring and ranking the vulnerability of pumping stations to trash blockage. In this approach, a trash blockage vulnerability index (TBVI) is developed based on the concepts of exposure, sensitivity and resilience. Using a graph-based network analysis technique, the proposed TBVI is applied to assess and rank the vulnerability of pumping stations in one of the most representative coastal mega-cities − Jakarta, Indonesia. The results show that TBVI can point to the pumping stations that are most vulnerable to trash blockage. Such information are vital to decision makers when planning and prioritising infrastructure to be serviced or upgraded as part of flood preparedness in coastal cities

Assessing the vulnerability of hydrological infrastructure to flood damage in coastal cities of developing nations

Hydrological infrastructure such as pumps, floodgates (or sluice gates), dams, embankments, and flood barriers are invaluable assets used for controlling water in flood-prone areas such coastal cities. These infrastructure components are often vulnerable to damage or failure due to the impact of floodwaters, thus leaving people and urban property exposed to flood hazards. To minimise the failure of hydrological infrastructure during intense flooding events, it is important to identify the most vulnerable components and to invest scarce resources in reducing their vulnerability. Using the concepts of exposure, susceptibility and resilience, this study proposes a graph-based network approach for measuring the vulnerability of hydrological infrastructure to flood damage in coastal cities. In this graph-based approach, hydrological infrastructures are represented as network nodes and the waterways as edges. The proposed vulnerability assessment approach is applied to measure and rank the vulnerability of floodgates in one of the most exemplary coastal cities - Jakarta, Indonesia. The results show that the proposed solution is both useful in highlighting the most vulnerable infrastructure components and also providing clues as to what actions can be taken to minimise infrastructure vulnerability. More so, the solution was found to be useful in identifying potential locations within the city of Jakarta, where additional infrastructure are required to improve resilience to flooding. This type of information about infrastructure vulnerability and resilience actions is vital to decision-making authorities responsible for planning, flood preparedness and priority-based allocation of resources for the maintenance of flood control infrastructure in coastal cities

Exploring Multi-Touch Contact Size For Z-Axis Movement In 3D Environments

In this paper we examine two methods for using relative contact size as an interaction technique for 3D environments on multi-touch capacitive touch screens. We refer to interpreting relative contact size changes as pressure simulation. We conducted a 2 x 2 withinsubjects experimental design using two methods for pressure estimation (calibrated and comparative) and two different 3D tasks (bidirectional and unidirectional). Calibrated pressure estimation was based upon a calibration session, whereas comparative pressure estimation was based upon the contact size of each initial touch. The bidirectional task was guiding a ball through a hoop, while the unidirectional task involved using pressure to rotate a stove knob. Results indicate that the preferred and best performing pressure estimation technique was dependent on the 3D task. For the bidirectional task, calibrated pressure performed significantly better, while the comparative method performed better for the unidirectional task. We discuss the implications and future research directions based on our findings

Towards User-Defined Multi-Touch Gestures For 3D Objects

Although multi-touch interaction in 2D has become widespread on mobile devices, intuitive ways to interact with 3D objects has not been thoroughly explored. We present a study on natural and guided multi-touch interaction with 3D objects on a 2D multi-touch display. Specifically, we focus on interactions with 3D objects that have either rotational, tightening, or switching components on mechanisms that might be found in mechanical operation or training simulations. The results of our study led to the following contributions: a classification procedure for determining the category and nature of a gesture, an initial user-defined gesture set for multi-touch gestures applied to 3D objects, and user preferences with regards to metaphorical versus physical gestures. © 2013 ACM

Towards User-Defined Multi-Touch Gestures for 3D Objects

Although multi-touch interaction in 2D has become widespread on mobile devices, intuitive ways to interact with 3D objects has not been thoroughly explored. We present a study on natural and guided multi-touch interaction with 3D objects on a 2D multi-touch display. Specifically, we focus on interactions with 3D objects that have either rotational, tightening, or switching components on mechanisms that might be found in mechanical operation or training simulations. The results of our study led to the following contributions: a classification procedure for determining the category and nature of a gesture, an initial user-defined gesture set for multi-touch gestures applied to 3D objects, and user preferences with regards to metaphorical versus physical gestures