bluuebunny/crossref_metadata_2025 huggingface dataset:
A Teleoperated Microsurgical Robot and Associated Virtual Environment for Eye Surgery
Authors: Hunter Ian W. , Doukoglou Tilemachos D. , Lafontaine Serge R. , Charette Paul G. , Jones Lynette A. , Sagar Mark A. , Mallinson Gordon D. , Hunter Peter J.
Published: December 2015

We have developed a prototype teleoperated microsurgical robot (MSR-1) and associated virtual environment for eye surgery. Bidirectional pathways relay visual, auditory, and mechanical information between the MSR-1 master and slave. The surgeon wears a helmet (visual master) that is used to control the orientation of a stereo camera system (visual slave) observing the surgery. Images from the stereo camera system are relayed back to the helmet (or adjacent screen) where they are viewed by the surgeon. In each hand the surgeon holds a pseudotool (a shaft shaped like a microsurgical scalpel) that projects from the left and right limbs of a force reflecting interface (mechanical master). Movements of the left and right pseudotools cause corresponding movements (scaled down by 1 to 100 times) in the microsurgical tools held by the left and right limbs of the micromotion robot (mechanical slave) that performs the surgery. Forces exerted on the left and right limbs of the slave microsurgical robot via the microtools are reflected back (after being scaled up by 1 to 100 times) to the pseudotools and hence surgeon via actuators in the left and right limbs of the mechanical master. This system enables tissue cutting forces to be felt including those that would normally be imperceptible if they were transmitted directly to the surgeon's hands. The master and slave subsystems (visual, auditory, and mechanical) communicate through a computer system which serves to enhance and augment images, filter hand tremor, perform coordinate transformations, and perform safety checks. The computer system consists of master and slave computers that communicate via an optical fiber connection. As a result, the MSR-1 master and slave may be located at different sites, which permits remote robotic microsurgery to become a reality. MSR-1 is being used as an experimental testbed for studying the effects of feedforward and feedback delays on remote surgery and is used in research on enhancing the accuracy and dexterity of microsurgeons by creating mechanical and visual telepresence.
Using a Maximum Error Statistic to Evaluate Measurement Errors in 3D Position and Orientation Tracking Systems
Authors: Morris Ted , Donath Max
Published: December 2015

One approach to tracking anatomical and robot joint motion consists of tracking the XYZ locations of multiple point targets that are attached to each of the moving segments and then computing the three translations and three orientation angles between adjoining segments. The complexity of such systems requires that we introduce a new conservative maximum error statistic to be used for evaluating the accuracy of 3D motion tracking systems. This paper addresses the various phenomena that contribute to measurement error when computing six degrees of freedom associated with the relative motion between the adjacent segments. The characteristics of these errors, common to many 3D motion tracking systems, were first determined by experimentation using one such system (MnSCAN). These and additional artifacts were then modeled in order to quantitatively evaluate their effects using the maximum error statistic. Based on these computer experiments, several relationships were identified that predict how each of these phenomena influences the predicted measurement of relative motion between bodies. These suggest where design emphasis should be placed in order to minimize the error in tracking the six degrees of freedom. The methodology and the conclusions based on these results can be applied to designing most six degree of freedom position and motion measurement systems.
An Integrated Virtual Environment System
Authors: Hahn James K. , Gritz Larry , Darken Rudolph , Geigel Joseph , Lee Jong Won
Published: December 2015

Virtual environment research involves a number of related problems from a variety of domains. A joint research at the George Washington University and the Naval Research Laboratory is bringing together issues from these domains to study the factors that contribute to an integrated virtual environment. The research can be divided into three general categories: human factors, motion control, and sound synchronization. Human factors issues involve the development of new paradigms for movement and navigation, essential for performance of general tasks in virtual spaces. Novel approaches to motion control are being explored to help users of virtual environments interact and control virtual objects. This involves both interactive control as well as automation through evolutionary approaches. The sounds being generated as a result of these motions are modeled with compositional techniques to parameterize and synchronize them to the events in the environment. The research is being approached from both a fundamental point of view typical of an academic environment as well as from an application oriented point of view of interest to the Navy. The cooperative relationship has benefited both the George Washington University and the Naval Research Laboratory.
Evaluation Experiments of a Teleexistence Manipulation System
Authors: Tachi Susumu , Yasuda Kenichi
Published: December 2015

A teleexistence manipulation system was evaluated quantitatively by comparing tasks of tracking a randomly moving target under several operational conditions. The effects of various characteristics, e.g., binocular vision and the effect of natural arrangement of the head and the arm, are analyzed by comparing quantitatively the results under these operational conditions. A human tracking transfer function was measured and used for comparison. The results revealed the significant dominance of the binocular vision with natural arrangement of the head and arm, which is the most important characteristic of teleexistence.
Virtual Sand Box:Development of an Application of Virtual Environments for Clinical Medicine
Authors: Kijima Ryugo , Shirakawa Kimiko , Hirose Michitaka , Nihei Kenji
Published: December 2015

The sand play technique (Sandspiel) has often been used in psychological treatments. The primary purpose of this study was to construct a practical virtual environment to support the application of this technique with computers. The prototype application called “Virtual Sand Box” was developed to test the Sand Play Technique in the diagnosis and treatment of autistic patients. The display system and input device are discussed. A detailed description is also provided for how a virtual environment was constructed to cater input systems into output systems in order to facilitate manipulation tasks for the user. Experimental results gave insight into the feasibility and advantages of applying virtual reality technology to clinical medicine, particularly with respect to the diagnosis of the people with psychological and psychiatric sicknesses such as autism and neurosis.
Depth of Presence in Virtual Environments
Authors: Slater Mel , Usoh Martin , Steed Anthony
Published: December 2015

This paper describes a study to assess the influence of a variety of factors on reported level of presence in immersive virtual environments. It introduces the idea of “stacking depth,” that is, where a participant can simulate the process of entering the virtual environment while already in such an environment, which can be repeated to several levels of depth. An experimental study including 24 subjects was carried out. Half of the subjects were transported between environments by using virtual head-mounted displays, and the other half by going through doors. Three other binary factors were whether or not gravity operated, whether or not the subject experienced a virtual precipice, and whether or not the subject was followed around by a virtual actor. Visual, auditory, and kinesthetic representation systems and egocentric/exocentric perceptual positions were assessed by a preexperiment questionnaire. Presence was assessed by the subjects as their sense of “being there,” the extent to which they experienced the virtual environments as more the presenting reality than the real world in which the experiment was taking place, and the extent to which the subject experienced the virtual environments as places visited rather than images seen. A logistic regression analysis revealed that subjective reporting of presence was significantly positively associated with visual and kinesthetic representation systems, and negatively with the auditory system. This was not surprising since the virtual reality system used was primarily visual. The analysis also showed a significant and positive association with stacking level depth for those who were transported between environments by using the virtual HMD, and a negative association for those who were transported through doors. Finally, four of the subjects moved their real left arm to match movement of the left arm of the virtual body displayed by the system. These four scored significantly higher on the kinesthetic representation system than the remainder of the subjects.
Intelligent Assistive Technologies
Authors: Barry Philip , Dockery John , Littman David , Barry Melanie
Published: December 2015

Intelligent assistive technology (IAT) refers to the integration of existing assistive technology with artificial intelligence (AI) techniques and advanced environment interfaces. AI can be used to integrate a great deal of sensor information, to amplify primary intent as well as to conduct background tasks. Through the application of AI we believe that we can level the playing field for persons with disabilities and maximize existing and future capabilities of assistive devices. By beginning a dialogue now between the developers of AI and assistive technology, IAT can become a reality.
Human Factors Engineering of a Virtual Laboratory for Students with Physical Disabilities
Authors: Nemire Kenneth , Burke Adam , Jacoby Richard
Published: December 2015

Medical advances, new legislation, and changing social attitudes have encouraged more students with disabilities to enter college. Educational systems consequently must continue to respond to the unique needs of these Individuals by developing adaptive educational tools. Laboratory courses requiring hands-on experience, such as physics and biology, are challenging to students with physical limitations. One promising and innovative way to provide access is through virtual environment technology, which can provide a unique tool for students with physical disabilities by offering opportunities for mobility and manipulative exploration without requiring physical access, dexterity, and strength. We are developing a virtual physics laboratory that should benefit students with physical disabilities by providing them greater control over their environment and more educational opportunities. These benefits also will be realized by nondisabled students. We discuss some of the issues and technologies employed to design the laboratory, including user needs analyses, task analyses, and assessment of current technologies.
NPSNET:A Network Software Architecture for LargeScale Virtual Environments
Authors: Macedonia Michael R. , Zyda Michael J. , Pratt David R. , Barham Paul T. , Zeswitz Steven
Published: December 2015

This paper explores the issues involved in designing and developing network software architectures for large-scale virtual environments. We present our ideas in the context of NPSNET-IV, the first 3-D virtual environment that incorporates both the IEEE 1278 distributed interactive simulation (DIS) application protocol and the IP multicast network protocol for multiplayer simulation over the Internet.
AVIARY:Design Issues for Future Large-Scale Virtual Environments
Authors: Snowdon David N. , West Adrian J.
Published: December 2015

VR is already evolving away from single user small-scale demonstrators, and inexorably toward sophisticated environments in which many geographically distributed users can perform a diverse range of activities. There will therefore be a pressure to make such environments increasingly general purpose and dynamic in their support of applications, paralleling perhaps the historical evolution of conventional operating systems. It is from speculations about the nature of such a future large-scale VR system that the AVIARY project has developed. AVIARY provides multiple worlds, each with its own set of laws, that may be tailored to suit particular application domains. The overall structure enables a coherent relationship between worlds to be maintained, which is important both for purposes of code reuse, and to aid users in navigating the system. A prototype implementation exists that addresses underlying implementation issues in the AVIARY model, and, in particular, distribution across heterogeneous processor networks, dynamic management of objects and message types within the system, the separation of graphics processing, and the management of spatial extent. Implementations of the prototype have been tested on a Transputer array, and a heterogeneous network of Sun and Silicon Graphics workstations. The system is currently being ported to a 2.4-Gflop KSR-1 parallel supercomputer. This paper reviews approaches to distributed, multi-application VR systems, presents pertinent elements of the AVIARY design, and describes the prototype implementation with particular attention given to the issues of distribution.
Use of the Remote Access Virtual Environment Network (RAVEN) for Coordinated IVA—EVA Astronaut Training and Evaluation
Authors: Cater John P. , Huffman Stephen D.
Published: December 2015

This paper presents a unique virtual reality training and assessment tool developed under a NASA grant, “Research in Human Factors Aspects of Enhanced Virtual Environments for Extravehicular Activity (EVA) Training and Simulation.” The Remote Access Virtual Environment Network (RAVEN) was created to train and evaluate the verbal, mental, and physical coordination required between the intravehicular (IVA) astronaut operating the Remote Manipulator System (RMS) arm and the EVA astronaut standing in foot restraints on the end of the RMS. The RAVEN system currently allows the EVA astronaut to approach the Hubble Space Telescope (HST) under control of the IVA astronaut and grasp, remove, and replace the Wide Field Planetary Camera drawer from its location in the HST. Two viewpoints, one stereoscopic and one monoscopic, were created all linked by Ethernet, that provided the two trainees with the appropriate training environments.
The VR—Link™ Networked Virtual Environment Software Infrastructure
Authors: Morrison John
Published: December 2015

Four challenges to building large networked virtual environments (NVEs) are ever-increasing complexity, fidelity, scalability, and portability. We require a powerful, flexible, efficient, portable software infrastructure to overcome these challenges. We examine one such example, software infrastructure, which is currently the basis of dozens of NVE efforts. Its use of modern object-oriented inheritance and its use of an interpreted configuration programming language meet these requirements while achieving the efficiency to support thousands of entities on current-generation hardware.
Recombinant Architecture
Authors: Mitchell William J.
Published: December 2015

As advanced telecommunications and telepresence systems allow artificial adjacency to substitute for physical adjacency among activities, many traditional building types are likely to fragment and recombine. Built spaces will still be needed for living, work, and recreation, but they will be organized and configured in new ways. This paper examines a variety of traditional building types and sketches some plausible scenarios for their transformation in the digital telecommunications era.
Architectural Anatomy
Authors: Feiner Steven K. , Webster Anthony C. , Krueger Theodore E. , MacIntyre Blair , Keller Edward J.
Published: December 2015

We provide an overview of the early stages of three related research projects whose goals are to exploit augmented reality, virtual worlds, and artificial intelligence to explore relationships between perceived architectural space and the structural systems that support it. In one project, we use a see-through head-mounted display to overlay a graphic representation of a building's structural systems on the user's view of a room within the building. This overlaid virtual world shows the out-lines of the concrete joists, beams, and columns surrounding the room, as well as the reinforcing steel inside them, and includes displays from a commercially available structural analysis program. In a related project, the structural view is exposed by varying the opacity of room finishes and concrete in a 3D model of the room and surrounding structure rendered on a conventional CRT. We also describe a hypermedia database, currently under construction, depicting major, twentieth-century American buildings. The interactive, multidisciplinary elements of the database—including structural and thermal analyses, free body diagrams (which show how forces are resisted by portions of a structure under various loading conditions), facsimiles of construction documents, and critical essays—are bound together and made available over the World-Wide Web. Finally, we discuss the relationships among all these projects, and their potential applications to teaching architecture students and to construction, assembly, and repair of complex structures.
The Sense of Presence for the Suddenly Deafened Adult:Implications for Virtual Environments
Authors: Gilkey Robert H. , Weisenberger Janet M.
Published: December 2015

Reports from adventitiously deafened individuals of a sense of unconnectedness with their surroundings, of a sense that the world seems “dead,” offer a compelling rationale for the argument that auditory cues are a crucial determinant of the sense of presence. Moreover, the crucial element of auditory stimulation for creating a sense of presence may be the auditory background, comprising the incidental sounds made by objects in the environment, rather than the communication and warning signals that typically capture our attention. Although designers of virtual environments have most often tried to maximize the sense of presence in the user by attempting to improve the fidelity of visual displays, the arguments presented here suggest that background auditory stimulation may be useful or even critical for achieving a full sense of presence.
Tactile Display of Vibratory Information in Teleoperation and Virtual Environments
Authors: Kontarinis Dimitrios A. , Howe Robert D.
Published: December 2015

This paper investigates the use of tactile displays for conveying task-related vibrations in teleoperation and virtual environments. Vibration displays can be implemented with inexpensive, open loop devices that can be added to many existing systems to improve performance. We describe the design of our prototype vibration sensing and display system, and experimentally demonstrate the utility of this type of tactile feedback. We also delineate the kinds of tasks where high-frequency vibratory feedback is important. In inspection and exploration tasks the detection of vibrations can be the fundamental goal of the task, while in some manipulation tasks vibrations can enhance performance by reducing reaction times or permitting minimization of ferees. Design guidelines for implementation of vibration displays, based on simple mechanical models, are also presented.
A Two-Handed Interface for Object Manipulation in Virtual Environments
Authors: Mapes Daniel P. , Moshell J. Michael
Published: December 2015

A two-handed direct manipulation VE (virtual environment) interface has been developed as an intuitive manipulation metaphor for graphical objects. A new input device called ChordGloves introduces a simple technique for rapid and repeatable gesture recognition; the Chordgloves emulate a pair of 3-D mice and a keyboard. A drafting table is isomorphically mapped into the VE and provides hand support for 2-D interface techniques, as well as a reference frame for calibrating the mapping between real and virtual worlds. A cursor gravity function is used to grab vertices, edges, or faces and establish precisely aligned differential constraints between objects called anchors. The capability of subjects to translate, rotate, scale, align, and glue objects is tested with a puzzle building task. An approximation of the puzzle task is done in Adobe Illustrator to provide a performance reference. Results and informal user observations as well as topics for future work are presented.
Comments on the Use of Olfactory Displays for Virtual Environments
Authors: Barfield Woodrow , Danas Eric
Published: December 2015

Currently, the hardware to produce virtual environments does not include olfactory displays, in spite of the fact that a wealth of sensory information is available from the olfactory sense. This paper reviews the physiological and psychological aspects of olfaction and discusses the use of olfactory displays for virtual environments. Further, it outlines the information that will be needed by the virtual environment research community to integrate olfactory stimuli into virtual environments.
Effect of Frame Rate and Force Feedback on Virtual Object Manipulation
Authors: Richard Paul , Birebent Georges , Coiffet Philippe , Burdea Grigore , Gomez Daniel , Langrana Noshir
Published: December 2015

Research on virtual environments (VE) produced significant advances in computer hardware (graphics boards and i/o tools) and software (real-time distributed simulations). However, fundamental questions remain about how user performance is affected by such factors as graphics refresh rate, resolution, control latencies, and multimodal feedback. This article reports on two experiments performed to examine dextrous manipulation of virtual objects. The first experiment studies the effect of graphics frame rate and viewing mode (monoscopic vs. stereoscopic) on the time required to grasp a moving target. The second experiment studies the effect of direct force feedback, pseudoforce feedback, and redundant force feedback on grasping force regulation. The trials were performed using a partially-immersive environment (graphics workstation and LCD glasses), a DataGlove, and the Rutgers Master with force feedback. Results of the first experiment indicate that stereoscopic viewing is beneficial for low refresh rates (it reduced task completion time by about 50% vs. monoscopic graphics). Results of the second experiment indicate that haptic feedback increases performance and reduces error rates, as compared to the open loop case (with no force feedback). The best performance was obtained when both direct haptic and redundant auditory feedback were provided to the user. The large number of subjects participating in these experiments (over 160 male and female) indicates good statistical significance for the above results.
Virtual Reality Calibration and Preview/Predictive Displays for Telerobotics
Authors: Kim Won S.
Published: December 2015

A virtual reality (VR) calibration technique of matching a virtual environment of simulated three-dimensional (3-D) graphic models with actual camera views of the remote site task environment has been developed. This VR calibration enables high-fidelity preview/predictive displays with calibrated graphics overlay on live video. Reliable and accurate calibration is achieved by operator-interactive camera calibration and object localization procedures based on new linear/nonlinear least-squares algorithms that can handle multiple-camera views. Since the object pose becomes known through the VR calibration, the operator can now effectively use the semiautomatic computer-generated trajectory mode in addition to the manual teleoperation mode. The developed VR calibration technique and the resultant high fidelity preview/predictive displays were successfully utilized in a recent JPL/NASA-GSFC (Jet Propulsion Laboratory/Goddard Space Flight Center) telerobotic servicing demonstration. Preview/predictive displays were very useful for both noncontact and contact tasks, providing an effective VR interface with immediate visual prediction/verification to the operator. The positioning alignment accuracy achieved using four-camera views in inserting a tool into the ORU hole was 0.51 cm on the average with a 1.07 cm maximum error at 95% confidence level. Results also indicate that the object localization with two well-chosen, e.g., near orthogonal camera views, could be nearly as accurate as that with four-camera views.
Presence of Mind:A Reaction to Thomas Sheridan's “Further Musings on the Psychophysics of Presence”
Authors: Ellis Stephen R.
Published: December 2015

An operators' sense of remote presence during teleoperation or use of virtual environment interfaces is analyzed as to what characteristics it should have to qualify it as an explanatory scientific construct. But the implicit goal of designing virtual environment interfaces to maximize presence is itself questioned in a second section in which examples of human—machine interfaces beneficially designed to avoid a strong sense of egocentric presence are cited. In conclusion, it is argued that the design of a teleoperation or virtual environment system should generally focus on the efficient communication of causal interaction. In this view the sense of presence, that is of actually being at the simulated or remote workplace, is an epiphenomena of secondary importance for design.
The Effects of Pictorial Realism, Delay of Visual Feedback, and Observer Interactivity on the Subjective Sense of Presence
Authors: Welch Robert B. , Blackmon Theodore T. , Liu Andrew , Mellers Barbara A. , Stark Lawrence W.
Published: December 2015

Two experiments examined the effects of pictorial realism, observer interactivity, and delay of visual feedback on the sense of “presence.” Subjects were presented pairs of virtual environments (a simulated driving task) that differed In one or more ways from each other. After subjects had completed the second member of each pair they reported which of the two had produced the greater amount of presence and indicated the size of this difference by means of a 1-100 scale. As predicted, realism and interactivity increased presence while delay of visual feedback diminished it. According to subjects' verbal responses to a postexperiment Interview, pictorial realism was the least influential of the three variables examined. Further, although some subjects reported an increase in the sense of presence over the course of the experiment, most said that it had remained unchanged or become weaker.
Effectiveness of Virtual Environment Desensitization in the Treatment of Agoraphobia
Authors: North Max M. , North Sarah M. , Coble Joseph R.
Published: December 2015

The primary purpose of this study was to investigate the effectiveness of virtual environment technology in the area of psychotherapy. In particular, this study investigated the effectiveness of virtual environment desensitization (VED) in the treatment of agoraphobia (fear of being in places or situations from which escape might be difficult or embarrassing). Sixty undergraduate college students served as subjects. Thirty subjects served in the experimental group and the other 30 served as a control group. Subjects' degree of fear/anxiety was measured using two instruments, the Attitude Towards Agoraphobia Questionnaire (ATAQ) and the Subjective Units of Discomfort Scale (SUDS). Only subjects in the experimental group were exposed to the VED treatment. The scores of the control group did not change significantly, while both ATAQ and SUDS scores decreased significantly for the experimental group. The average SUDS scores of the experimental group decreased steadily across sessions, indicating steady improvement with treatment. It is hoped that this research will be a first step toward the utilization of virtual environment technology in providing more effective, economical, and confidential treatment of psychological disorders.
Implementation of Dynamic Robotic Graphics For a Virtual Control Panel
Authors: Gruenbaum P. E. , McNeely W. A. , Sowizral H. A. , Overman T. L. , Knutson B. W.
Published: December 2015

This paper describes an implementation of “robotic graphics,” in which forces and torques are provided in virtual environments by the method of interacting with robots that are not attached to the body. The demonstration simulates a flat control panel containing an assortment of switches by using an immersive virtual reality head-mounted display, electro-magnetic and videometric tracking, and a robot that holds a turret containing one of each of the types of switches. The robot dynamically presents the switches to be touched in a just-in-time only-as-needed basis. Results are presented regarding visual/force registration for finger tracking and human performance.
Virtual Reality (VR) and Psychotherapy: Opportunities and Challenges
Authors: Glantz Kalman , Durlach Nathaniel I. , Barnett Rosalind C. , Aviles Walter A.
Published: December 2015

Virtual reality technology is now being used to provide exposure and desensitization for a number of phobic conditions. In this paper, we first review these current applications and discuss the work needed to refine and expand these applications to phobias. We then comment briefly on some preliminary applications of VR technology to mental-health problems outside the domain of phobias. Finally, we consider ways in which VR might be used to further enhance psychotherapy and assist in the treatment of a wide variety of disorders. Various possible interventions are discussed, along with the technological developments needed to make them possible.
A Virtual Reality-Based System for Hand Diagnosis and Rehabilitation
Authors: Burdea Grigore , Deshpande Sonal , Langrana Noshir , Gomez Daniel , Liu Biao
Published: December 2015

This article describes a new and unified approach to computerized hand diagnosis and rehabilitation. The system uses a workstation to automate diagnosis data collection and analysis and to assess the rehabilitation progress. A new diagnosis glove was developed and tested. This device measures grasping forces applied to 16 regions of the hand. A physician using this system can also utilize modern diagnosis devices such as electronic dynamometer, pinchmeter, and goniometer. Additionally, three VR rehabilitation exercises were created using WorldToolKit graphics library and run on the same workstation. These exercises were modeled after standard hand rehabilitation procedures and involve manipulation of virtual objects and transparent real-time data gathering. Grasping forces were modeled and fed back using the Rutgers Master worn on the patient's hand. An Oracle database was used to store, analyze, and integrate the patient's diagnosis and rehabilitation data. The system is presently undergoing clinical trials.
Experiments Using Multimodal Virtual Environments in Design for Assembly Analysis
Authors: Gupta Rakesh , Sheridan Thomas , Whitney Daniel
Published: December 2015

The goal of this work is to investigate whether estimates of ease of part handling and part insertion can be provided by multimodal simulation using virtual environment (VE) technology. The long-term goal is to use this data to extend computer-aided design (CAD) systems in order to evaluate and compare alternate designs using design for assembly analysis. A unified, physically-based model has been developed for modeling dynamic interactions and has been built into a multimodal VE system called the Virtual Environment for Design for Assembly (VEDA). The designer sees a visual representation of objects, hears collision sounds when objects hit each other, and can feel and manipulate the objects through haptic interface devices with force feedback. Currently these models are 2D in order to preserve interactive update rates. Experiments were conducted with human subjects using a two-dimensional peg-in-hole apparatus and a VEDA simulation of the same apparatus. The simulation duplicated as well as possible the weight, shape, size, peg-hole clearance, and fictional characteristics of the physical apparatus. The experiments showed that the multimodal VE is able to replicate experimental results in which increased task completion times correlated with increasing task difficulty (measured as increased friction, increased handling distance, and decreased peg-hole clearance). However, the multimodal VE task completion times are approximately twice those of the physical apparatus completion process. A number of possible factors have been identified, but the effect of these factors has not been quantified.
A Survey of Augmented Reality
Authors: Azuma Ronald T.
Published: December 2015

This paper surveys the field of augmented reality (AR), in which 3D virtual objects are integrated into a 3D real environment in real time. It describes the medical, manufacturing, visualization, path planning, entertainment, and military applications that have been explored. This paper describes the characteristics of augmented reality systems, including a detailed discussion of the tradeoffs between optical and video blending approaches. Registration and sensing errors are two of the biggest problems in building effective augmented reality systems, so this paper summarizes current efforts to overcome these problems. Future directions and areas requiring further research are discussed. This survey provides a starting point for anyone interested in researching or using augmented reality.
Augmented Reality through Wearable Computing
Authors: Starner Thad , Mann Steve , Rhodes Bradley , Levine Jeffrey , Healey Jennifer , Kirsch Dana , Picard Rosalind W. , Pentland Alex
Published: December 2015

Wearable computing moves computation from the desktop to the user. We are forming a community of networked, wearable-computer users to explore, over a long period, the augmented realities that these systems can provide. By adapting its behavior to the user's changing environment, a body-worn computer can assist the user more intelligently, consistently, and continuously than a desktop system. A text-based augmented reality, the Remembrance Agent, is presented to illustrate this approach. Video cameras are used both to warp the visual input (mediated reality) and to sense the user's world for graphical overlay. With a camera, the computer could track the user's finger to act as the system's mouse; perform face recognition; and detect passive objects to overlay 2.5D and 3D graphics onto the real world. Additional apparatus such as audio systems, infrared beacons for sensing location, and biosensors for learning about the wearer's affect are described. With the use of input from these interface devices and sensors, a long-term goal of this project is to model the user's actions, anticipate his or her needs, and perform a seamless interaction between the virtual and physical environments.
A Framework for Immersive Virtual Environments (FIVE): Speculations on the Role of Presence in Virtual Environments
Authors: Slater Mel , Wilbur Sylvia
Published: December 2015

This paper reviews the concepts of immersion and presence in virtual environments (VEs). We propose that the degree of immersion can be objectively assessed as the characteristics of a technology, and has dimensions such as the extent to which a display system can deliver an inclusive, extensive, surrounding, and vivid illusion of virtual environment to a participant. Other dimensions of immersion are concerned with the extent of body matching, and the extent to which there is a self-contained plot in which the participant can act and in which there is an autonomous response. Presence is a state of consciousness that may be concomitant with immersion, and is related to a sense of being in a place. Presence governs aspects of autonomie responses and higher-level behaviors of a participant in a VE. The paper considers single and multiparticipant shared environments, and draws on the experience of ComputerSupported Cooperative Working (CSCW) research as a guide to understanding presence in shared environments. The paper finally outlines the aims of the FIVE Working Group, and the 1995 FIVE Conference in London, UK.
A Comparison of Cybersickness Incidences, Symptom Profiles, Measurement Techniques, and Suggestions for Further Research
Authors: Kennedy Robert S. , Lanham D. Susan , Drexler Julie M. , Massey Catherine J. , Lilienthal Michael G.
Published: December 2015

The widespread use of virtual environment (VE) systems in a variety of applications has serious implications for the user. Users with access to these sophisticated interactive “immersions” in multisensory, three-dimensional (3D) synthetic environments have been shown to experience motion sickness-like symptoms (i.e., eyestrain, ataxia, fatigue, drowsiness) and aftereffects such as visual flashbacks, disorientation, and balance disturbances occasionally occurring up to 12 hours after VE exposure. This is a significant health and safety concern. Technical improvements of VE systems need to be initiated to reduce these potential aftereffects that could result in adverse legal, economic, individual, and social consequences. Many different types of symptoms have been reported that appear to make up the cybersickness syndrome. From our extensive database of virtual environment and flight simulator exposures, we offer examples of these symptoms profiles along with suspected mechanisms and origins. We discuss these issues as well as various assessment techniques and methods used to determine the presence of VE sickness in individuals.
The Precise Issue Henry Adams, Global War, and the Role of Force in American History
Authors: Carter Stephen D.
Published: December 2015

War, imperialism, interstate conflict, military force—highlighting and reevaluating these concerns as central to the content, form, and context of Henry Adams’s History of the United States lays the groundwork for a new interpretation of the categories of war and force in his thought.
A NOTE ON THE ORIGINS OF “UNCLE SAM,” 1810–1820
Authors: Hickey Donald R.
Published: December 2015

Conventional wisdom holds that “Uncle” Sam Wilson—a Troy, New York, meatpacker who, when he was supplying troops during the War of 1812, stamped his crates “U.S.”—inspired the federal government’s nickname; new evidence suggests, however, that the personification originated earlier, simply as a creative and colorful expansion of “U.S.”
The lichen genus Cetrelia (Parmeliaceae, Ascomycota) in india
Authors: Mishra Gaurav Kumar
Published: December 2015

A detailed morpho-taxonomic account of ten species of the lichen genus Cetrelia occurring in India is provided. Cetrelia chicitae (W.L. Culb.) W.L. Culb. & C.F. Culb., is reported as new to India. A key to all worldwide known taxa of Cetrelia is provided.
Piper peltatifolium, a new species of Piperaceae from Hainan, China
Authors: Chao-Yun Hao , Yun-Hong Tan , Li-Song Hu , Le-He Tan , Hai-Ping Chen , Xia-Wei Qin , Gang Wu , Hua-Song Wu
Published: December 2015

Piper peltatifolium, a new species of Piperaceae from Hainan, China, is here described and illustrated. The new species is morphologically similar to P. hongkongense, but the former can be easily distinguished by the combination of characteristics: trophophyll blades peltate and subleathery with nonbranched hairs; leaves with longer sheaths; stamens usually only two; anthers ovoid and shorter than filaments; ovaries ellipsoid to ovoid; stigmas 3 or 4, or rarely 5; bracts suborbicular, sessile, and adnate to rachis; and drupes slightly hispidulous.
Leucoagaricus viridariorum (Agaricaceae, Agaricales), a new species from Spain
Authors: Munoz Guillermo , Caballero Agustin , Salom Joan Carles , Ercole Enrico , Vizzini Alfredo
Published: December 2015

Leucoagaricus viridariorum is proposed as a new species based on material collected in different areas of Spain. This taxon is characterised macroscopically by its small, whitish basidiomes, minutely squamulose-fibrillose pileus, evanescent ascendant annulus and growth in man-made environments. Microscopically, its subglobose to broadly ellipsoid spores, the clavate cheilocystidia and the trichodermic pileipellis are diagnostic. Based on molecular data of the internal transcribed spacer of nuclear ribosomal DNA (nrITS) this species belongs to the Leucoagaricus/Leucocoprinus clade of the Agaricaceae where it is sister to Leucoagaricus amanitoides.
Three new Solomon’s Seals (Polygonatum: Asparagaceae) from the Eastern Himalaya
Authors: Floden Aaron Jennings
Published: December 2015

Three new Polygonatum (Asparagaceae) are described and illustrated from the Eastern Himalaya. These species, Polygonatum autumnale, P. angelicum, and P. luteoverrucosum, have opposite leaves and are evergreen. The foremost is the first autumn-flowering species in the genus and is known from a single locality in Arunachal Pradesh, India. Polygonatum angelicum and P. luteoverrucosum are the first species in the genus to be reported with distinctly verrucose perigone surfaces. These two are sympatric in Arunachal Pradesh, India, and Xizang, China, but occur at different elevations. Their relationships to other opposite-leaved species are discussed and a key is provided to these and related species.
Comparing CAM5 and Superparameterized CAM5 Simulations of Summer Precipitation Characteristics over Continental East Asia: Mean State, Frequency–Intensity Relationship, Diurnal Cycle, and Influencing Factors
Authors: Zhang Yi , Chen Haoming
Published: December 2015

Numerical experiments are conducted to investigate the differences between summer precipitation over continental East Asia simulated by the Community Atmosphere Model, version 5 (CAM5), and superparameterized CAM5 (SPCAM5, a multiscale modeling framework). The results show that SPCAM5 effectively alleviates several original biases. Overestimates of precipitation on the eastern periphery of the Tibetan Plateau are reduced from CAM5 to SPCAM5 as a result of decreases in both the average hourly precipitation frequency and mean hourly intensity. Underestimates along the coastal regions in southern China are improved following a corresponding increase in mean hourly intensity and a decrease in average hourly precipitation frequency. The frequency–intesnsity relationship is also more realistic in SPCAM5. For western China, overestimated frequency values (in CAM5) of both weak-to-moderate (0–20 mm day−1) and heavy (20–50 mm day−1) intensity ranges are reduced in SPCAM5. For southern China, overestimates of frequency values (in CAM5) in the weak-to-moderate range are also reduced, whereas underestimates in the intense ranges are enhanced. In terms of diurnal variability, SPCAM5 generally exhibits a delay in the afternoon peak time and greater diurnal amplitude. The possible physical reasons for the variations in the precipitation between the models are further investigated. It is found that the change in deep convection intensity is a primary factor governing the shift in the precipitation simulations. SPCAM5 better simulates an intermediate transition stage from shallow to deep convection, which helps the deep convection to grow more fully to a greater magnitude, thus delaying the peak time and increasing the precipitation maxima.
The Utility of Convection-Permitting Ensembles for the Prediction of Stationary Convective Bands
Authors: Barrett Andrew I. , Gray Suzanne L. , Kirshbaum Daniel J. , Roberts Nigel M. , Schultz David M. , Fairman Jonathan G.
Published: December 2015

This study examines convection-permitting numerical simulations of four cases of terrain-locked quasi-stationary convective bands over the United Kingdom. For each case, a 2.2-km-grid-length, 12-member ensemble and a 1.5-km-grid-length deterministic forecast are analyzed, each with two different initialization times. Object-based verification is applied to determine whether the simulations capture the structure, location, timing, intensity, and duration of the observed precipitation. These verification diagnostics reveal that the forecast skill varies greatly between the four cases. Although the deterministic and ensemble simulations captured some aspects of the precipitation correctly in each case, they never simultaneously captured all of them satisfactorily. In general, the models predicted banded precipitation accumulations at approximately the correct time and location, but the precipitating structures were more cellular and less persistent than the coherent quasi-stationary bands that were observed. Ensemble simulations from the two different initialization times were not significantly different, which suggests a potential benefit of time-lagging subsequent ensembles to increase ensemble size. The predictive skill of the upstream larger-scale flow conditions and the simulated precipitation on the convection-permitting grids were strongly correlated, which suggests that more accurate forecasts from the parent ensemble should improve the performance of the convection-permitting ensemble nested within it.
A Note on Testing Mediated Effects in Structural Equation Models
Authors: Valente Matthew J. , Gonzalez Oscar , Miočević Milica , MacKinnon David P.
Published: December 2015

Methods to assess the significance of mediated effects in education and the social sciences are well studied and fall into two categories: single sample methods and computer-intensive methods. A popular single sample method to detect the significance of the mediated effect is the test of joint significance, and a popular computer-intensive method to detect the significance of the mediated effect is the bias-corrected bootstrap method. Both these methods are used for testing the significance of mediated effects in structural equation models (SEMs). A recent study by Leth-Steensen and Gallitto 2016 provided evidence that the test of joint significance was more powerful than the bias-corrected bootstrap method for detecting mediated effects in SEMs, which is inconsistent with previous research on the topic. The goal of this article was to investigate this surprising result and describe two issues related to testing the significance of mediated effects in SEMs which explain the inconsistent results regarding the power of the test of joint significance and the bias-corrected bootstrap found by Leth-Steensen and Gallitto 2016. The first issue was that the bias-corrected bootstrap method was conducted incorrectly. The bias-corrected bootstrap was used to estimate the standard error of the mediated effect as opposed to creating confidence intervals. The second issue was that the correlation between the path coefficients of the mediated effect was ignored as an important aspect of testing the significance of the mediated effect in SEMs. The results of the replication study confirmed prior research on testing the significance of mediated effects. That is, the bias-corrected bootstrap method was more powerful than the test of joint significance, and the bias-corrected bootstrap method had elevated Type 1 error rates in some cases. Additional methods for testing the significance of mediated effects in SEMs were considered and limitations and future directions were discussed.