topauthor: Thomas_G* : Human-Computer Interaction Bibliography Search

[1] ImmersiveMe'15: 3rd ACM International Workshop on Immersive Media Experiences Workshop Summaries / Chambel, Teresa / Viana, Paula / Bove, V. Michael / Strover, Sharon / Thomas, Graham Proceedings of the 2015 ACM International Conference on Multimedia 2015-10-26 p.1339-1340

ACM Digital Library Link

Summary: This ACM International Workshop on Immersive Media Experiences is in its 3rd edition. Since 2013 in Barcelona, it has been a meeting point of researchers, students, media producers, service providers and industry players in the area of immersive media environments, applications and experiences. After the successful first edition at ACM Multimedia 2013 and the consolidation of the theme and the team at Orlando in 2014, ImmersiveMe'15 aims at bringing to the stage new ideas and developments that keep this topic as appealing as in the previous editions. ImmersiveMe'15 will now take place in Brisbane and, again, it will be a platform to present interesting and out-of-the-box new work that contributes to make the world more interactive, immersive and engaging.

[2] ImmersiveMe'14: 2nd ACM international workshop on immersive media experiences Workshop Summaries / Chambel, Teresa / Viana, Paula / Bove, V. Michael / Strover, Sharon / Thomas, Graham Proceedings of the 2014 ACM International Conference on Multimedia 2014-11-03 p.1255-1256

ACM Digital Library Link

Summary: The 2nd ACM International Workshop on Immersive Media Experiences (ImmersiveMe'14) at ACM Multimedia aims at bringing together researchers, students, media producers, service providers and industry players in the emergent area of immersive media experiences, through the exploration of different scenarios, applications, and neighboring fields. This second edition, after a successful first edition at ACM Multimedia 2013, provides a platform for presenting on-going work, to consolidate and tie different research communities working on this engaging area, as well as to point directions for the future.

[3] Immersive media experiences: ImmersiveMe 2013 workshop at ACM multimedia Workshops overview / Chambel, Teresa / Bove, V. Michael / Strover, Sharon / Viana, Paula / Thomas, Graham Proceedings of the 2013 ACM International Conference on Multimedia 2013-10-21 p.1095-1096

ACM Digital Library Link

Summary: Immersive media has the potential for strong impact on users' emotions and their sense of presence and engagement. The main objective of this workshop is to bring together researchers, students, media producers, service providers and industry players in the area of emergent immersive media. The workshop will provide a platform for a deep discussion on ongoing work, recent achievements and experiences. It is expected not only to consolidate experiences but also to identify aspects where strong collaboration among all the interested players is needed and to point towards future working directions.

[4] Perception of Meta-Information Representation: A Psychophysical Approach Cognitive Engineering and Decision Making: CE3 -- Advances in Support System Design / Fortenbery, Nicholas / Jenkins, Michael P. / Bisantz, Ann M. / D'Arcy, Jean-François / Farry, Michael / Nagy, Allen / Roth, Emilie / Pfautz, Jonathan / Thomas, Gina Proceedings of the Human Factors and Ergonomics Society 2012 Annual Meeting 2012-10-22 p.218-222

doi 10.1177/1071181312561053

Link to HFES Digital Content

Summary: Previous research has identified many effective methods to visualize different types of meta-information, or information qualifiers; however, these methods are often incorporated without understanding how the graphical codes are perceived and how the encoded information is interpreted by display users. This results in display designers selecting graphical codes to represent meta-information without empirical evidence to determine the appropriateness of these selections. To help address this lack of guidance, this paper presents a systematic study of how people perceive two graphical codes (saturation and opacity) and relate those codes to different types of meta-information. Results were generated using psychophysical scaling methods, and provide visualization designers with a means to more appropriately design meta-information representations.

[5] Differences in Novice and Experienced Driver Response to Lane Departure Warnings that Provide Active Intervention Surface Transportation: ST2 -- Driver Assistance Systems / Hollopeter, Nicole / Brown, Timothy / Thomas, Geb Proceedings of the Human Factors and Ergonomics Society 2012 Annual Meeting 2012-10-22 p.2216-2220

doi 10.1177/1071181312561467

Link to HFES Digital Content

Summary: It is widely known that young drivers are over-represented in the crash data for reasons such as risk perception and acceptance, age, gender, experience, exposure, and social contexts. The current mitigations implemented to address this issue consist mainly of graduated driver's licenses and parental involvement programs. However, as technology begins to find its way into transportation in the form of advanced driver assistance systems, there is a need to understand whether these technologies will be a benefit or a detriment to young novice drivers. This effort investigates the reactions of young novice drivers to a control intervention lane departure warning. The results show less urgent reactions to the warning from novice drivers compared to the older more experienced drivers tested. Young novice males were found to have degraded performance compared to their novice female peers as well as older more experienced male drivers. This study provides useful insights concerning the necessary investigations of effects of advanced driver assistance systems on young novice drivers and the associated young driver safety epidemic.

[6] An Investigation of Learning Style and Discipline in a Human Factors Course Education: E2 - The Science of Pedagogy / Schall, Mark C., Jr. / Rusch, Michelle L. / Thomas, Geb / Lee, John D. Proceedings of the Human Factors and Ergonomics Society 55th Annual Meeting 2011-09-19 p.555-559

doi: 10.1177/1071181311551113

Link to HFES Digital Content

Summary: This study investigated adjustments made to learning materials for an Industrial Engineering Human Factors course at a public research university in the United States. Adjustments were made in an attempt to improve student comprehension of course content. Modifications included creating alternative homework assignments, design exercises, active classroom learning lessons, and lecture presentations to accommodate learning styles defined by Kolb's experiential learning theory. The same instructor taught the course before and after adjustment. Performance scores (e.g. homework, quizzes, exams) were used to evaluate whether or not the changes in course materials were associated with an improvement in student comprehension of material. Results suggested that while the adjusted materials educated all learning styles similarly, they did not significantly improve student performance. Significant differences were found across various disciplines; however, adjustments reduced these differences over the course of the semester.

[7] Improving Patient Safety With Hand Hygiene Compliance Monitoring Heath Care: HC15 - Novel Technologies Used in Health Care / Thomas, Geb / Polgreen, Philip / Herman, Ted / Sharma, Deepti / Johns, Brian / Chen, Howard / Scranton, Gregg / Naylor, David / Ireland, Michael / McCarty, Tina / Decker, Tim / Segre, Alberto Proceedings of the Human Factors and Ergonomics Society 55th Annual Meeting 2011-09-19 p.823-827

doi: 10.1177/1071181311551171

Link to HFES Digital Content

Summary: Hand hygiene is important for patient safety; increasing hand hygiene compliance may reduce the frequency of healthcare-associated infections. This paper describes a distributed system that uses instrumented product dispensers and doorway monitors to systematically measure hand hygiene compliance as an alternative to compliance measurements by human observers, which is the current standard. The paper describes two experiments. The first experiment monitored 4,266 doorway crossings and 858 hand hygiene dispenser events for 4 patient rooms over 80 consecutive hours. The second experiment was part of a larger effort that included a direct comparison of a human observer with the automatically recorded observations. The results of the two experiments suggest that large quantities of data could be readily acquired, but the data was sensitive to several limitations not suffered by human observers including: distinguishing between single versus closely spaced multiple threshold crossings and distinguishing staff from patients and visitors. However, a direct comparison of human versus machine readings suggested that the system might overcome observational challenges faced by the human observers, providing more consistent and reliable measurements.

[8] GoSlow: designing for slowness, reflection and solitude alt.chi: ... and I just can't take it anymore! / Cheng, Justin / Bapat, Akshay / Thomas, Gregory / Tse, Kevin / Nawathe, Nikhil / Crockett, Jeremy / Leshed, Gilly Proceedings of ACM CHI 2011 Conference on Human Factors in Computing Systems 2011-05-07 v.2 p.429-438

ACM Digital Library Link

Summary: We are surrounded by technologies that fuel a fast-paced, at-the-moment, connected life. In contrast, GoSlow is a mobile application designed to help users slow down, contemplate, and be alone. Through serendipWe are surrounded by technologies that fuel a fast-paced, at-the-moment, connected life. In contrast, GoSlow is a mobile application designed to help users slow down, contemplate, and be alone. Through serendipitous moments of pause and reflection, GoSlow offers simple ways for users to cut back and relax, provides an outlet for contemplation and reminiscence, and helps them disconnect and get away. Our user study reveals that GoSlow encourages introspective reflection, slowing down, and can help reduce stress with minimal intervention.itous moments of pause and reflection, GoSlow offers simple ways for users to cut back and relax, provides an outlet for contemplation and reminiscence, and helps them disconnect and get away. Our user study reveals that GoSlow encourages introspective reflection, slowing down, and can help reduce stress with minimal intervention.

[9] Meta-Information Representation and Communication COGNITIVE ENGINEERING AND DECISION MAKING: Meta-Information Communication and Representation / Pfautz, Jonathan / Roth, Emilie / Bisantz, Ann / Jackson, Cullen / Thomas, Gina / Trafton, Greg / Whitaker, Randy Proceedings of the Human Factors and Ergonomics Society 51st Annual Meeting 2007-10-01 v.51 p.225-228

Link to HFES Digital Content

Summary: Increasingly, the study of cognition and action in complex sociotechnical systems has revealed that humans reason about both information and the qualifications of that information. These qualifications, or meta-information (e.g., pedigree, recency, uncertainty), play a role in human performance across work domains (Pfautz et al., 2006). Meta-information contextualizes information, and therefore can critically influence how a human will process, understand, and act on that information. This panel will discuss the role of meta-information in the design and evaluation of visualization and decision-support systems.

[10] Directed stigmergy-based control for multi-robot systems Posters / Steele, Fitzgerald, Jr. / Thomas, Geb Proceedings of the ACM/IEEE International Conference on Human-Robot Interaction 2007-03-10 p.223-230

Keywords: human robot interaction, multi-robot, robotics, stigmergy, supervisory control, swarm, user interface

ACM Digital Library Link

Summary: Multi-robot systems are particularly useful in tasks that require searching large areas such as planetary science exploration, urban search and rescue, or landmine remediation. In order to overcome the inherent complexity of controlling multiple robots, the user must be able to give high-level, goal driven direction to the robot team. Since human robot interaction is a relatively new discipline, it is helpful to look to existing systems for concepts, analogies, or metaphors that might be utilized in building useful systems. Inspiration from natural decentralized systems guides the development of a computer simulation for stigmergy-based control of multi-robot system, and the interface with which an operator can interact and control mobile robots. In-depth description of the design process includes a description of a basic stigmergy-based control system and an innovative Directed Stigmergy control system that facilitates operator control of the robot team in an interesting and surprisingly effective way.

[11] Categorizing Adverse Medical Device and Medication Event Frequency HEALTH CARE: Adverse Events and Reporting Systems in Health Care / Thornburg, Kristopher / Thomas, Geb / Draper, Scott Proceedings of the Human Factors and Ergonomics Society 50th Annual Meeting 2006-10-16 v.50 p.1009-1013

Link to HFES Digital Content

Summary: Much of the research interest in reducing adverse medical events emphasizes medical device interfaces and software design. Infusion pump programming has enjoyed particular research attention. This study categorized 1260 adverse medical event reports at three Midwestern hospitals. Although an important contributor, infusion pump programming contributes to fewer adverse events than the amount of literature implies. More common problems involve opening the intravenous infusion piggyback clamp and medication identification.

[12] Searching for a quantitative proxy for rover science effectiveness Metrics and work study practices / Pudenz, Erin / Thomas, Geb / Glasgow, Justin / Coppin, Peter / Wettergreen, David / Cabrol, Nathalie Proceedings of the 1st ACM SIGCHI/SIGART Conference on Human-Robot Interaction 2006-03-02 p.18-25

Keywords: human robot interaction (HRI), mobile robots, remote rover exploration, supervisory control, teleoperation interface

ACM Digital Library Link

Summary: During two weeks of study in September and October of 2004, a science team directed a rover and explored the arid Atacama Desert in Chile. The objective of the mission was to search for life. Over the course of the mission the team gained experience with the rover and the rover became more reliable and autonomous. As a result, the rover/operator system became more effective. Several factors likely contributed to the improvement in science effectiveness including increased experience, more effective search strategies, different science team composition, different science site locations, changes in rover operational capabilities, and changes in the operation interface. However, it is difficult to quantify this effectiveness because science is a largely creative and unstructured task. This study considers techniques that quantify science team performance leading to an understanding of which features of the human-rover system are most effective and which features need further development. Continuous observation of the scientists throughout the mission led to coded transcripts enumerating each scientific statement. This study considers whether six variables correlate with scientific effectiveness. Several of these variables are metrics and ratios related to the daily rover plan, the time spent programming the rover, the number of scientific statements made and the data returned. The results indicate that the scientists created more complex rover plans without increasing the time to create the plans. The total number of scientific statements was approximately equal (2187 versus 2415) for each week. There was a 50% reduction in bytes of returned data between the two weeks resulting in an increase in scientific statements per byte of returned data ratio. Of the original six, the most successful proxies for science effectiveness were the time to program each rover task and the number of scientific statements related to data delivered by the rover. Although both these measures have face validity and were consistent with the results of this experiment, their ultimate empirical utility must be measured further.

[13] Cognitive comparison of 3D interaction in front of large vs. small displays Interaction and design -- II / Tyndiuk, F. / Thomas, G. / Lespinet-Najib, V. / Schlick, C. Proceedings of the 2005 ACM Symposium on Virtual Reality Software and Technology 2005-11-07 p.117-123

Keywords: cognitive aids, display size, interaction, virtual reality, visual attention

ACM Digital Library Link

Summary: This paper presents some experimental results on the comparison of users performance for different kinds of 3D interaction tasks (travel, manipulation), when using either a standard desktop display or a large immersive display. The main results of our experimentation are the following: first, not all users benefit similarly from the use of large displays, and second, the gains of performance strongly depend on the nature of the interaction task. To explain these results, we borrow some tools from cognitive science in order to identify one cognitive factor (visual attention) that is involved in the difference of performance that can be observed.

[14] Two Dimensional Finite Element Modeling to Identify Physiological Bases for Tactile Gap Discrimination GENERAL SESSION: General Sessions Potpourri / Gerling, Gregory J. / Thomas, Geb W. Proceedings of the Human Factors and Ergonomics Society 49th Annual Meeting 2005-09-26 v.49 p.891-895

Link to HFES Digital Content

Summary: Tactile edge and gap detection are fundamental to performing manual tasks. Because slowly adapting type I (SA-I) mechanoreceptors encode details pertinent to edge localization, understanding low-level encoding is critical to understanding edge perception. Solid mechanics models may help us understand how mechanoreceptors in the skin encode applied surface indentation into neural signals representing edges. Finite element models test whether an indenter separated by a gap creates unique stress/strain distributions in models based upon orientation to fingerprint lines. Results indicate that a gap axis parallel to ridge lines elicits a more pronounced signal than a gap axis perpendicular to ridge lines. The differences may be due to underlying intermediate ridge microstructure. The percentage differences for three derived stress metrics range from 30-87% greater when the indenter's gap axis parallels the ridges. This initial effort demonstrates that underlying skin microstructure may aid tactile perception of stimulus orientation.

[15] Displaying Small Surface Features with a Force Feedback Device in a Dental Training Simulator VIRTUAL ENVIRONMENTS: Human Interactions in Virtual Environments / Thomas, Geb W. / Liu, Li Proceedings of the Human Factors and Ergonomics Society 49th Annual Meeting 2005-09-26 v.49 p.2235-2239

Link to HFES Digital Content

Summary: This paper describes two algorithms for representing small (< 100 µm) step edges with a force feedback simulator. The first algorithm is the traditional spring-damper force feedback model that represents the cursor's present position as a point. The second, new, model represents the cursor as a small sphere. A forced-choice experiment with eight participants indicates that people can judge the height of small edges more reliably with the sphere model. The results are useful for the development of simulators for training fine haptic skills. They are more generally useful to human factors professionals in the haptics community because they describe how to overcome a fundamental perceptual challenge with haptic stimulators.

[16] Error-Associated Behaviors and Error Rates for Robotic Geology COGNITIVE ENGINEERING AND DECISION MAKING: Error Analysis and Decision Quality / Wagner, Jacob / Thomas, Geb / Glasgow, Justin / Anderson, Robert C. / Cabrol, Nathalie / Grin, Edmond Proceedings of the Human Factors and Ergonomics Society 48th Annual Meeting 2004-09-20 v.48 p.444-447

Link to HFES Digital Content

Summary: Humans are often blamed for errors in complex systems. A number of taxonomies exist for classifying human errors, but recent doubts have been raised as to whether these are actually errors or simply processes involved in both correct and incorrect decisions. A field test was designed to address some of these issues. During the field test, three geologists made assessments about the recent and past environment based on robotically collected data. The decisions were classified based on previous error taxonomy. Each conclusion was then checked for accuracy. From this data, the error rate for specific behaviors could be calculated. The results indicate many of the behaviors describe earlier as erroneous actually produce correct decisions most of the time. One behavior is singled out as producing a majority of the errors and further research is needed to better understand its causes.

[17] The Identification of the Critical Haptic Stimulus Features in a Clinical Dental Task STUDENT FORUM: Cutting-Edge Research by Students I / Liu, Li / Thomas, Geb / Stanford, Clark / Johnson, Lynn Proceedings of the Human Factors and Ergonomics Society 48th Annual Meeting 2004-09-20 v.48 p.2137-2141

Link to HFES Digital Content

Summary: This paper reviews evidence from a series of experiments that identify a characteristic 250-350 Hz tool vibration that may enable a dentist to make a specific clinical determination during a dental exam. The specific task is a generalized version of crown margin gap estimation. The results suggest that the vibration of the dental tool may be the salient haptic characteristic perceived by the dentist. Our previous experiments indicate that this vibration occurs when the probe releases potential energy after moving across the gap. A Fourier power spectrum of the vibration indicates that the vibration energy is in the maximally sensitive range of the Pacinian corpuscle, an organ which senses fingertip skin vibration. This paper discusses follow-up experiments designed to verify that including the vibration makes the size of the crown margin gap more salient while damping the vibration makes the size of crown margin gap more difficult to estimate. Defining the essential characteristics of the haptic signal is essential for redesigning, implementing and assessing the next generation of our dental surgical simulator.

[18] Dynamic Simulator for Training Clinical Breast Examination MEDICAL SYSTEMS AND REHABILITATION: Ergonomic and Training Issues in Medical Systems Development [Lecture] / Gerling, Gregory J. / Thomas, Geb W. / Weissman, Alicia M. / Dove, Edwin L. Proceedings of the Human Factors and Ergonomics Society 46th Annual Meeting 2002-09-30 v.46 p.1472-1476

Link to HFES Digital Content

Summary: Clinical breast examinations (CBE) play a role in the detection of breast cancers. However, most physicians receive inadequate training in tactile search of breast tissue to detect small (< 2 cm), hard tumors. The dynamic, variable-lump, silicone breast simulator was designed to improve physicians' CBE performance and increase tumor detection. Water inflates balloons embedded in formed silicone to simulate the presence of tumors and allow independent adjustment of tumor hardness. The advantage, compared to static models with five, non-movable tumors, is that training scenarios can be reconfigured and repeated until each trainee learns the subtle tactile cues associated with tumors. In a study of 48 medical students, training with the dynamic simulator increased the number of tumors found (F(42)=7.85, p=0.0077), reduced the number of false positives (F(42)=5.20, p=0.0277), and improved transfer of training. This advancement can allow CBE to become more reliable, consistent, and effective.

[19] The Effects of Pictograph Explicitness on Hazard Perceptions POSTERS / Alves-Foss, Janice D. / Thomas, Gregory W. / Braun, Curt C. Proceedings of the Human Factors and Ergonomics Society 39th Annual Meeting 1995-10-09 v.2 p.934

WARNING: THE ABSTRACT OF THIS ENTRY HAS NOT BEEN VALIDATED

Summary: Little is known about how warning label pictographs representing the same hazard condition compare in effectiveness. Thirty-three undergraduate students viewed six pictographs that varied across three levels of pictograph explicitness (high, medium and low) and two hazard conditions (electric shock and hand trauma). Subjects rated each pictograph on five variables: hazardousness, carefulness, likelihood of injury, severity of injury and exaggeration of the hazard. A composite variable named "perceived hazard" was formed from the averaged ratings of hazardousness and carefulness. Results showed that increasing explicitness was associated with higher levels of perceived hazard, likelihood of injury and severity of injury. The data also indicated that increases in explicitness were viewed as exaggerations of the hazard. These results suggest that the pictograph can play a role in communicating varying levels of hazard.

[20] Designing Computers with People in Mind Features: Article / Garrison, Anne / Mountford, S. Joy / Thomas, Greg interactions 1994 v.1 n.2 p.60-69

Broken Link to ACM Digital Library

Summary: The authors describe three prototype products from the Apple Interface Design Project.

[21] Modeling Pilot Expertise in Air Combat TRAINING: Analyzing Workload, Modeling Expertise, and Maintaining Motivation in Experiments / Thomas, Gary S. / Obermayer, Richard W. / Raspotnik, William B. / Waag, Wayne L. Proceedings of the Human Factors Society 36th Annual Meeting 1992-10-12 v.2 p.1331-1334

Summary: The purpose of this effort was to model expert pilot performance and decision making in one-versus-one (1v1) air-to-air combat. Several knowledge-elicitation techniques were used to extract air combat expertise from a former fighter pilot, who served as the subject-matter-expert (SME). Unstructured and then structured interviews were used to elicit the goals and sub-goals of air-to-air combat, plus some of the pilot behaviors necessary to accomplish the goals. The SME also flew a number of combat sorties against another former fighter pilot in the Simulator for Air-to-Air Combat (SAAC) to demonstrate pilot performance required to accomplish the goals of air combat. Based on the SME's verbal protocols, a group of air combat rules were developed. A rule-based production system was then designed to incorporate the resulting knowledge base. The production system was also designed to be capable of analyzing an existing data base of air combat engagements. Expert system development required additional input from the SME to identify specific values of flight parameters required by the production system. Upon completion and SME verification of the expert model, it will be validated by comparing its performance to that of our SME in simulated air-to-air combat. If the model can successfully describe expert pilot performance, the model will be used to provide diagnostic performance feedback in conjunction with SAAC training.

[22] Training Potential of Multiplayer Air Combat Simulation Training: Training Device Design / Houck, Michael R. / Thomas, Gary S. / Bell, Herbert H. Proceedings of the Human Factors Society 33rd Annual Meeting 1989-10-16 v.2 p.1300-1304

WARNING: THE ABSTRACT OF THIS ENTRY HAS NOT BEEN VALIDATED

Summary: The objective of this investigation was to identify air combat mission tasks that could be trained using existing multiship simulator technology. Forty-two mission ready F-15 pilots and 16 tactical air controllers rated their need for additional training on 41 air combat tasks. These pilots and controllers then participated in four days of air combat training using McDonnell Aircraft Company's simulation facility. This training allowed the participants to practice two-ship tactics in an unrestricted combat environment which included multiple air and ground threats, electronic combat, and real-time kill removal. Following training, the participants rated the value of their current unit training and training provided by the multiship simulation. Pilots rated the multiship simulator training superior to their current unit training for 22 of the 41 air combat tasks. Pilots also rated their need for additional training in those 22 combat tasks from "very" to "extremely" desirable. The controllers indicated that all combat tasks were better trained in the multiplayer simulation than in their current unit training program. Interviews and questionnaires also identified a number of strengths and weaknesses of the simulation that provide "lessons learned" for the development and use of future multiplayer air combat simulations.

[23] Development of an Air Combat Performance Measure Training: Performance Assessment Techniques and Applications / Thomas, Gary S. / Miller, David C. Proceedings of the Human Factors Society 32nd Annual Meeting 1988-10-24 v.2 p.1207-1211

WARNING: THE ABSTRACT OF THIS ENTRY HAS NOT BEEN VALIDATED

Summary: The purpose of this research was to formulate a unitary measure of performance of simulated one-versus-one, within visual range, air-to-air combat. The measure will serve as a criterion for the development and validation of specific measures of ACM skill that can be used to provide diagnostic performance feedback to pilots. Two experiments were conducted in which fighter pilots served as judges and rank-ordered, from most to least desirable, hypothetical ACM engagement outcomes. Outcome variables included (1) whether or not the hypothetical pilot achieved a "kill", (2) whether or not he survived the mission, (3) the percent of time the pilot was in an offensive, defensive, or neutral posture, (4) length of engagement, and (5) posture at the beginning and end of the engagement (offensive, defensive, or neutral). In order to determine inter-rater agreement among judges in Experiment I, their rankings were correlated. Correlations ranged from .93 to .99. Pilots' rankings of engagement outcomes were subjected to linear regression analyses to derive equations that could be used as a unitary measure of ACM success. The regression equation in Experiment I accounted for 95% of the variance in rankings, and the composite regression model calculated in Experiment II accounted for more than 70% for the variance.