Implicit Communication Research Articles

Composing dataflow analyses and transformations

Dataflow analyses can have mutually beneficial interactions. Previous efforts to exploit these interactions have either (1) iteratively performed each individual analysis until no further improvements are discovered or (2) developed "super-analyses" that manually combine conceptually separate analyses. We have devised a new approach that allows analyses to be defined independently while still enabling them to be combined automatically and profitably. Our approach avoids the loss of precision associated with iterating individual analyses and the implementation difficulties of manually writing a super-analysis. The key to our approach is a novel method of implicit communication between the individual components of a super-analysis based on graph transformations. In this paper, we precisely define our approach; we demonstrate that it is sound and it terminates; finally we give experimental results showing that in practice (1) our framework produces results at least as precise as iterating the individual analyses while compiling at least 5 times faster, and (2) our framework achieves the same precision as a manually written super-analysis while incurring a compile-time overhead of less than 20%.

Performance-driven facial animation: basic research on human judgments of emotional state in facial avatars.

Virtual reality is rapidly evolving into a pragmatically usable technology for mental health (MH) applications. As the underlying enabling technologies continue to evolve and allow us to design more useful and usable structural virtual environments (VEs), the next important challenge will involve populating these environments with virtual representations of humans (avatars). This will be vital to create mental health VEs that leverage the use of avatars for applications that require human-human interaction and communication. As Alessi et al.1 pointed out at the 8th Annual Medicine Meets Virtual Reality Conference (MMVR8), virtual humans have mainly appeared in MH applications to "serve the role of props, rather than humans." More believable avatars inhabiting VEs would open up possibilities for MH applications that address social interaction, communication, instruction, assessment, and rehabilitation issues. They could also serve to enhance realism that might in turn promote the experience of presence in VR. Additionally, it will soon be possible to use computer-generated avatars that serve to provide believable dynamic facial and bodily representations of individuals communicating from a distance in real time. This could support the delivery, in shared virtual environments, of more natural human interaction styles, similar to what is used in real life between people. These techniques could enhance communication and interaction by leveraging our natural sensing and perceiving capabilities and offer the potential to model human-computer-human interaction after human-human interaction. To enhance the authenticity of virtual human representations, advances in the rendering of facial and gestural behaviors that support implicit communication will be needed. In this regard, the current paper presents data from a study that compared human raters' judgments of emotional expression between actual video clips of facial expressions and identical expressions rendered on a three-dimensional avatar using a performance-driven facial animation (PDFA) system developed at the University of Southern California Integrated Media Systems Center. PDFA offers a means for creating high-fidelity visual representations of human faces and bodies. This effort explores the feasibility of sensing and reproducing a range of facial expressions with a PDFA system. In order to test concordance of human ratings of emotional expression between video and avatar facial delivery, we first had facial model subjects observe stimuli that were designed to elicit naturalistic facial expressions. The emotional stimulus induction involved presenting text-based, still image, and video clips to subjects that were previously rated to induce facial expressions for the six universals2 of facial expression (happy, sad, fear, anger, disgust, and surprise), in addition to attentiveness, puzzlement and frustration. Videotapes of these induced facial expressions that best represented prototypic examples of the above emotional states and three-dimensional avatar animations of the same facial expressions were randomly presented to 38 human raters. The raters used open-end, forced choice and seven-point Likert-type scales to rate expression in terms of identification. The forced choice and seven-point ratings provided the most usable data to determine video/animation concordance and these data are presented. To support a clear understanding of this data, a website has been set up that will allow readers to view the video and facial animation clips to illustrate the assets and limitations of these types of facial expression-rendering methods (www. USCAvatars.com/MMVR). This methodological first step in our research program has served to provide valuable human user-centered feedback to support the iterative design and development of facial avatar characteristics for expression of emotional communication.

Normality, risk and the future: implicit communication of threat in health surveillance

In the practice of health surveillance, health professionals have to cope with the task of communicating outcomes of tests and measurements, as well as counselling individuals about present and future threats to their own or their children’s health. Research in this field has shed some light on the ‘language of risk’ and its implications for how the individual understands and deals with health in everyday life. Here, we want to further this exploration of the language of risk and to discuss the meaning of risk, normality and deviance. We focus on the implicit or explicit introduction and interpretation of threat in the communication between health professionals and patients in two programmes of health surveillance: child health surveillance and surveillance of 40‐year‐old men. Common themes in these two versions of health surveillance are discussed in relation to the meaning of risk, normality and threats for the future.

No Need for a Body Model: Positive Velocity Feedback for the Control of an 18‐DOF Robot Walker

In a multilegged walking robot several legs usually have ground contact and thereby form a closed kinematic chain. The control of such a system is generally assumed to require the explicit calculation of the body kinematics. Such a computation requires knowledge concerning all relevant joint angles as well as the segment lengths. Here, we propose a biologically inspired solution that does not need such a body model. This is done by using implicit communication through the body mechanics (embodiment) and a local positive velocity feedback strategy (LPVF) on the single joint level. In this control scheme the locally measured joint velocity of an elastic joint is fed into the same joint during the next time step to maintain the movement. At the same time, an additional part of this joint controller observes the mechanical joint power to confine the positive feedback. This solution does not depend on changes of the geometry, e.g. length of individual segments, and allows for a simple solution of negotiation of curves. The principle is tested in a dynamics simulation on a six‐legged walker and, for the first time, also on a real robot.

Cooperative behaviors in multi-robot systems through implicit communication

We illustrate the Cooperation through Implicit Communication behavior-based approach used for developing the PaSo-Team (The University of Padua Simulated Soccer Robot Team), a multi-robot software system for soccer robot competitions promoted by the RoboCup Simulation League. The configuration of the environment, namely the robots’ relative positions depending on both the global task and the game dynamics, provides a source of implicit information about the robots’ intention to be involved in collective actions, making them able to cooperate implicitly. The soccer team performance can be tuned by triggering the arbitration module of any single robot to generate, as many as possible, suitable situations which hint to the team the action of scoring the goal. Some macroscopic parameters can be usefully introduced to evaluate the evolution of the whole multi-robot software system.

Cooperative transportation by two four-legged robots with implicit communication

In this paper, we show cooperative object transportation by two four-legged robots. To realize cooperative transportation with autonomy, we adopt implicit communication based cooperation. Each robot uses only its own sensors to estimate the state of a task. With this method, people can attend to the cooperation system without any changes. We will show an algorithm and two experiments; one is by two legged robots and the other is by one robot and a human.

MUSLIM FAMILIES AND FAMILY THERAPY

Muslim immigrant families living in the United States may well come to the attention of mental health professionals. This article examines the applicability of the Anglo-American models of family therapy to Muslim immigrant families. The most significant differences in value systems between the Muslim and Anglo-American cultures is Muslim families' preference for greater connectedness, a less flexible and more hierarchical family structure, and an implicit communication style. Systemic thinking, which deals with the pattern of relationships, is valid for all families regardless of cultural differences. However, the preferred directions of change for Muslim families need to be integrated into the assessment and goals for family therapy.

‘‘Don't take my word for it.’’—understanding Chinese speaking practices

The purpose of this article was to examine: (1) How do Chinese communicate? and (2) Why do Chinese communicate the way they do? Five major speaking practices in Chinese culture were identified and analyzed. They include: (a) han xu, or implicit communication; (b) ting hua, or listening-centeredness; (c) ke qi or politeness; (d) zi ji ren, or a focus on insiders; and (e) mian zi, or face-directed communication strategies. These five speaking practices are situated in the relational and other focus of the Chinese self, and support the deeply rooted Chinese beliefs about talk as well as role-directed relationships.

Implicit Assumptions and Communication in Statistics

Statistics is becoming an increasingly important component of the school curriculum. The subject provides students with opportunities to explore situations that they read about or face in their everyday lives. This article describes a statistics project that focuses on communicating conclusions and on understanding implicit assumptions that may affect conclusions based on the information. The ability to make a table and draw graphs and charts is an important component of statistical education. However, the ability to communicate ideas to others and understand implicit assumptions associated with data are key objectives of educating students for a world that increasingly relies on statistical information as a means of mass communication.

A reactive coordination scheme for a many-robot system

This paper presents a novel approach for coordinating a homogeneous system of mobile robots using implicit communication in the form of broadcasts. The broadcast-based coordination scheme was developed for the Army Ant swarm-a system of small, relatively inexpensive mobile robots that can accomplish complex tasks by cooperating as a team. The primary drawback, however, of the Army Ant system is that the absence of a central supervisor poses difficulty in the coordination and control of the agents. Our coordination scheme provides a global "group dynamic" that controls the actions of each robot using only local interactions. Coordination of the swarm is achieved with signals we call "heartbeats". Each agent broadcasts a unique heartbeat and responds to the collective behavior of all other heartbeats. We generate heartbeats with van der Pol oscillators. In this application, we use the known properties of coupled van der Pol oscillators to create predictable group behavior. Some of the properties and behaviors of coupled van der Pol oscillators are discussed in detail. We emphasize the use of this scheme to allow agents to simultaneously perform an action such as lifting, steering, or changing speed. The results of experiments performed on three actual heartbeat circuits are presented and the behavior of the realized system is compared to simulated results. We also demonstrate the application of the coordination scheme to global speed control.

Using Fine-Grain Threads and Run-Time Decision Making in Parallel Computing

Programming distributed-memory multiprocessors and networks of workstations requires deciding what can execute concurrently, how processes communicate, and where data is placed. These decisions can be made statically by a programmer or compiler, or they can be made dynamically at run time. Using run-time decisions leads to a simpler interface—because decisions are implicit—and it can lead to better decisions—because more information is available. This paper examines the costs, benefits, and details of making decisions at run time. The starting point is explicit fine-grain parallelism with any number (even thousands) of threads. Five specific techniques are considered: (1) implicitly coarsening the granularity of parallelism, (2) using implicit communication implemented by a distributed shared memory, (3) overlapping computation and communication, (4) adaptively moving threads and data between nodes to minimize communication and balance load, and (5) dynamically remapping data to pages to avoid false sharing. Details are given on the performance of each of these techniques as well as on their overall performance for several scientific applications.

Monitoring Methods of Multiple Robots using Communication for Human Interface System.

This paper first discusses cooperation between the human operator and the decentralized autonomous robotic system. To realize cooperation, the operator must know condition of the mutli robot system. Therefore, monitoring methods which let the operator know system's condition are needed. Then strategies of communication between the human interface and agents are discussed. We propose explicit and implicit communication strategies to monitor the system, and several monitoring methods to implement them: time-based and event-based monitoring for the explicit monitoring and eavesdropping messages for the implicit monitoring. We compare the monitoring methods in order to ascertain how much information the human operator can gather in each method using simulation. Finally, the characteristics of each monitoring methods are analyzed.

Parallel visualization algorithms: performance and architectural implications

Recently, a new class of scalable, shared-address-space multiprocessors has emerged. Like message-passing machines, these multiprocessors have a distributed interconnection network and physically distributed main memory. However, they provide hardware support for efficient implicit communication through a shared address space, and they automatically exploit temporal locality by caching both local and remote data in a processor's hardware cache. In this article, we show that these architectural characteristics make it much easier to obtain very good speedups on the best known visualization algorithms. Simple and natural parallelizations work very well, the sequential implementations do not have to be fundamentally restructured, and the high degree of temporal locality obviates the need for explicit data distribution and communication management. We demonstrate our claims through parallel versions of three state-of-the-art algorithms: a recent hierarchical radiosity algorithm by Hanrahan et al. (1991), a parallelized ray-casting volume renderer by Levoy (1992), and an optimized ray-tracer by Spach and Pulleyblank (1992). We also discuss a new shear-warp volume rendering algorithm that provides the first demonstration of interactive frame rates for a 256/spl times/256/spl times/256 voxel data set on a general-purpose multiprocessor. >

Flexible Language Constructs for Large Parallel Programs

The goal of the research described in this article is to develop flexible language constructs for writing large data parallel numerical programs for distributed memory (multiple instruction multiple data [MIMD]) multiprocessors. Previously, several models have been developed to support synchronization and communication. Models for global synchronization include single instruction multiple data (SIMD), single program multiple data (SPMD), and sequential programs annotated with data distribution statements. The two primary models for communication include implicit communication based on shared memory and explicit communication based on messages. None of these models by themselves seem sufficient to permit the natural and efficient expression of the variety of algorithms that occur in large scientific computations. In this article, we give an overview of a new language that combines many of these programming models in a clean manner. This is done in a modular fashion such that different models can be combined to support large programs. Within a module, the selection of a model depends on the algorithm and its efficiency requirements. In this article, we give an overview of the language and discuss some of the critical implementation details.

Inferring Operator Intent as a Basis for Aiding in Man-Machine Systems

Abstract Intent interpretation by observing and explaining operator actions provides a powerful means of implicit communication between a human operator and a man-machine system. While not always required in an operational system, knowledge of the intentions of the user may be quite useful as a basis for providing assistance via an intelligent interface. Using an model of operator intent, intelligent assistance can be provided while leaving the operator in total control. Specifically, assistance can be offered through information management, error monitoring, and adaptive aiding. In addition, the intent model facilitates implicit communications between the human operator and intelligent planners and situation assessors, allowing the human to guide the reasoning of the intelligent aiding systems without the added burden of explicitly communicating with them. The basic design of the intent inferencer is described from a high level. Knowledge representation used in the intent inferencer is discussed more extensively.

Communication: What happens during the First Encounter between Patient and Physiotherapist?

First encounters between patients and physiotherapists have been video-taped and analysed as part of a research-project. Emphasis was on both functional assessment and patterns of interaction. Three groups of physiotherapists participated; manual therapists, psychomotor therapists, and district physiotherapists. The three groups used different approaches when examining their patients. Thus they conveyed different messages of content, roles, and relationships. Commonly, communication is discussed and analysed separately from diagnostic and therapeutic activity. Rejecting such separation, it is argued that it is important to highlight the way in which physiotherapists relate to their patients through their professional actions. The focus in this article is the implicit communication in the physiotherapist's examination. For physiotherapists, as for doctors, the body is the basis of their work. It is emphasized that it is especially important to discuss the body in connection with implicit communication.

Human-computer interaction software: lessons learned, challenges ahead

The author presents a knowledge-based approach to enhance and support communication between humans and computers. His system architecture has an explicit communication channel between the human and the hardware and an implicit communication channel between the human's knowledge base and the computer's stored knowledge. The author uses two intelligent support systems, Framer and Crack, to illustrate this concept. He concludes with a pragmatic description of lessons learned and problems ahead. >

Two Simulation Studies Investigating Means of Human-Computer Communication for Dynamic Task Allocation

When tasks are allocated dynamically within a human-computer system, system performance depends upon effective communication between the human and the computer. The results are presented of simulation studies which investigate two means of human-to-computer communication: implicit communication, in which the human's planned actions are conveyed to the computer through a model of the human's action strategy; and explicit communication, in which the human overtly transmits decisions to the computer. The results indicate that the effectiveness of implicit communication depends upon both the predictive validity of the model employed and the computer task allocation strategy built upon the model. The effectiveness of explicit communication depends upon the time the human must devote to transmitting action plans to the computer. These simulations indicate the payoffs that can be realized by optimization of implicit and explicit human-computer communication. They also provide an efficient means to determine the appropriate mix of these communication techniques for a given situation. Perhaps the most interesting finding is that implicit communication based upon a model possessing only modest predictive validity is capable of enhancing system performance. This suggests that implementation of implicit communication within human-computer systems need not require the development and use of complex all-encompassing models of human performance.

Categories of Implicit Interpersonal Communication

The purpose of the present study was to develop a set of eight nonverbal displays consistent with the eight interpersonal roles specified by Leary in 1957. The development of these displays was also based on the notion of a convergence of theory and fact based on the work of Leary, Osgood, and Schlosberg. Naive subjects' reactions to each of the eight displays were elicited on Leary's Interpersonal Check List and a simplified bipolar adjective instrument. Naive subjects placed the nonverbal displays as predicted. The present study is viewed as a first step in determining if in fact these eight displays represent major categories of nonverbal behavior used in implicit communication.

Extended person-machine interface

Current computer natural language systems lack discourse capabilities. They mainly treat utterances in isolation and are not able to track the coherence of extended dialogue. In general, however, human communication and task performance are not accomplished in this manner. Useful interface systems should incorporate extended conversational power. In this paper, we present an abstract computational system for extended person-machine interface. The system is theoretically motivated by an investigation into the human conversational system. The computer system incorporates many of the rules used by individuals in everyday interactions. Use of these rules enable implicit communication between conversants about their underlying models of an interaction. They function in place of explicit meta-communication about the structure of an ongoing exchange. Such communication is necessary since building compatible models of an interaction is necessary for effective interaction. Providing a comparable system of rules for the computer is then mandatory if we expect it to be able to integrate subsequent requests and exchanges to earlier ones.