Design Of Assistance Systems Research Articles

Response preparation in a lane change task

Anticipation of future events is crucial for driving performance and safety. The aim of this study is to assess the relevance of theoretical frameworks of response preparation (response priming, movement integration theory) for driving. In a customised lane change task, valid and invalid primes were used to indicate the direction of the forthcoming lane changes. Reaction time (RT) and phase durations from steering movements served as dependent measures. In agreement with the theoretical considerations, we found a clear effect of validity on RT and steering kinematics. RTs were faster and the duration of the initial steering phase was shorter with valid than with invalid advance information. The experimental outcomes suggest that the theoretical considerations about benefits and costs of response preparation can be generalised to driving manoeuvres. Therefore, response priming paradigms might be well suited to investigate preparatory effects of advance information, e.g. in the context of advanced driving assistance systems. Practitioner summary: Benefits and costs of response preparation were assessed in the context of driving. The findings suggest that the understanding of preparatory processes is of relevance to enhance driving performance and safety. It is possible to derive some implications that may be useful for the design of assistance and information systems.

Model-Based Analysis of the Design of Assistance Systems

Model-Based Analysis of the Design of Assistance Systems

Untangling RFID Privacy Models

The rise of wireless applications based on RFID has brought up major concerns on privacy. Indeed nowadays, when such an application is deployed, informed customers yearn for guarantees that their privacy will not be threatened. One formal way to perform this task is to assess the privacy level of the RFID application with a model. However, if the chosen model does not reflect the assumptions and requirements of the analyzed application, it may misevaluate its privacy level. Therefore, selecting the most appropriate model among all the existing ones is not an easy task. This paper investigates the eight most well-known RFID privacy models and thoroughly examines their advantages and drawbacks in three steps. Firstly, five RFID authentication protocols are analyzed with these models. This discloses a main worry: although these protocols intuitively ensure different privacy levels, no model is able to accurately distinguish them. Secondly, these models are grouped according to their features (e.g., tag corruption ability). This classification reveals the most appropriate candidate model(s) to be used for a privacy analysis when one of these features is especially required. Furthermore, it points out that none of the models are comprehensive. Hence, some combinations of features may not match any model. Finally, the privacy properties of the eight models are compared in order to provide an overall view of their relations. This part highlights that no model globally outclasses the other ones. Considering the required properties of an application, the thorough study provided in this paper aims to assist system designers to choose the best suited model.

On the measurement of privacy as an attacker’s estimation error

A wide variety of privacy metrics have been proposed in the literature to evaluate the level of protection offered by privacy-enhancing technologies. Most of these metrics are specific to concrete systems and adversarial models and are difficult to generalize or translate to other contexts. Furthermore, a better understanding of the relationships between the different privacy metrics is needed to enable more grounded and systematic approach to measuring privacy, as well as to assist system designers in selecting the most appropriate metric for a given application. In this work, we propose a theoretical framework for privacy-preserving systems, endowed with a general definition of privacy in terms of the estimation error incurred by an attacker who aims to disclose the private information that the system is designed to conceal. We show that our framework permits interpreting and comparing a number of well-known metrics under a common perspective. The arguments behind these interpretations are based on fundamental results related to the theories of information, probability, and Bayes decision.

Design of a flat field concave-grating-based micro-Raman spectrometer for environmental applications

In order to simplify the design process of microfabricated concave gratings, simplified algorithms for fast characterization of the concave grating were developed. These algorithms can be used to assist system designers using ray-tracing software in the determination of optimum design parameters considering the requirements and restrictions for specific applications. According to the algorithms, it is feasible to design a flat field microconcave grating with a 4 mm grating radius as a key component in a micro-Raman spectrometer system for inline environmental monitoring applications. This microspectrometer operates over the spectral wavelength band from 785 nm to 1000 nm and has a spectral resolution of 2 nm at 900 nm. The total size of the system is 1 mm×4 mm×3.7 mm, making it one of the smallest for this wavelength range and spectrum resolution.

A Receiver Architecture for Devices in Wireless Body Area Networks

A receiver architecture suitable for devices in wireless body area networks is presented. Such devices require minimum physical size and power consumption. To achieve this the receiver should, therefore, be fully integrated in state-of-the-art complementary metal-oxide-semiconductor (CMOS) technology, and size and power consumption must be carefully considered at all levels of design. The chosen modulation is frequency shift keying, for which transmitters can be realized with high efficiency and low spurious emissions. A direct-conversion receiver architecture is used to achieve minimum power consumption and a modulation index equal to two is chosen, creating a midchannel notch in the modulated signal. A tailored demodulation structure has been designed to make the digital baseband compact and low power. To increase sensitivity it has been designed to interface with an analog decoder. Implementation in the analog domain minimizes the decoder power consumption. Antenna design and wave propagation are taken into account via simulations with phantoms. The 2.45-GHz ISM band was chosen as a good compromise between antenna size and link loss. An ultra-low power medium access scheme has been designed, which is used both for system evaluation and for assisting system design choices. Receiver blocks have been fabricated in 65-nm CMOS, and a radio-frequency front-end and an analog-to-digital converter have been measured. Simulations of the complete baseband have been performed, investigating impairments due to 1/f noise, frequency and time offsets.

Design of integrated vehicle control using driver models

The paper proposes the control design of a driver assistance system which takes into consideration the interaction between vehicle and driver. The driver models, which describe the driver behaviours and activities, are incorporated in the vehicle model in a closed-loop interconnection system. In the control scheme a predefined road trajectory required by the driver with a steering command is followed. While the driver reduces the lateral error from the desired path, the control system focuses on the minimization of the yaw rate error. The vehicle maneuvers are supported by two control signals, i.e., the brake yaw moment and the auxiliary steering angle. The control design, in which the performance specifications and priority between the actuators are handled, is based on the LPV method.

Design of an LPV-based integrated control for driver assistance systems

The paper proposes the control design of a driver assistance system which integrates the brake, the steering, and the suspension systems. During vehicle maneuvers the control system generates the brake yaw moments, the auxiliary front steering angle and the camber angles of the wheels. The performance specifications such as trajectory tracking and road stability are guaranteed by the local controllers, while the coordination of the components is provided by the supervisor. The independent design of local controllers requires that monitoring signals are built in the performance specifications of the control design. The role of the robust LPV methods, which are able to handle parameter-dependent performances and guarantee performance requirements, is crucial. The main steps of the integrated control from the modeling to the control design are presented. The operation of the control system is illustrated through simulation examples.

Robust Assist for Conveyance of Flexible Structures Taking Account of Structured Uncertainties and Vibration Influence to Operators

Power assist systems have been introduced to reduce workers' load in industrial production. The authors have studied on control systems for power assisted conveyance of flexible structures. Generally, the systems include influences of various kinds of uncertainties. One of them is vibration influence of controlled objects to operators. Another one is structured uncertainties such as nonlinear friction or parameter variations. This paper shows a robust assist system design by taking these uncertainties into account. It consists of an impedance controller, a disturbance accommodating optimal controller, a disturbance observer and a reaction force controller. The first and second elements have already been applied to the authors' previous paper. In addition, the disturbance observer is needed for eliminating the influence of the structured uncertainties. Moreover, taking the characteristic of the controlled object model into account, the simple reaction force controller is applied in order to eliminate the influence of the reaction force from the vibration reduction actuator. As a controlled object example, this paper adopts a power assist cart with a vibration system. The effectiveness of the proposed control system is verified by experiments and their corresponding simulations.

Application of Frequency-Shaped Disturbance Accommodating Optimal Control to Robust Assist for Conveyance of Flexible Structures

Power assist systems have been introduced to reduce workers' load in industrial production. The author has studied on control systems for power assisted conveyance of flexible structures. Generally, the systems include influences of various kinds of uncertainties. One of them is vibration influence of controlled objects to operators. Another one is structured uncertainty such as nonlinear friction or parameter variations. The author's previous paper proposed a robust assist system design by taking these uncertainties into account. It consisted of an impedance controller, a disturbance accommodating optimal controller, a disturbance observer and a reaction force controller. However, the nonlinear friction such as Coulomb friction often induces chattering motion. Such a motion may cause a controlled object spill-over instability because the previous control system design does not take influences of unstructured uncertainties into account. Therefore, this note provides a modified version of the previous design by using the frequency-shaped disturbance accommodating optimal control. This note adopts the same controlled object as the author's previous paper. The effectiveness of the modification is verified by simulations.

A unifying framework for iterative approximate best-response algorithms for distributed constraint optimization problems

AbstractDistributed constraint optimization problems (DCOPs) are important in many areas of computer science and optimization. In a DCOP, each variable is controlled by one of many autonomous agents, who together have the joint goal of maximizing a global objective function. A wide variety of techniques have been explored to solve such problems, and here we focus on one of the main families, namely iterative approximate best-response algorithms used as local search algorithms for DCOPs. We define these algorithms as those in which, at each iteration, agents communicate only the states of the variables under their control to their neighbours on the constraint graph, and that reason about their next state based on the messages received from their neighbours. These algorithms include the distributed stochastic algorithm and stochastic coordination algorithms, the maximum-gain messaging algorithms, the families of fictitious play and adaptive play algorithms, and algorithms that use regret-based heuristics. This family of algorithms is commonly employed in real-world systems, as they can be used in domains where communication is difficult or costly, where it is appropriate to trade timeliness off against optimality, or where hardware limitations render complete or more computationally intensive algorithms unusable. However, until now, no overarching framework has existed for analyzing this broad family of algorithms, resulting in similar and overlapping work being published independently in several different literatures. The main contribution of this paper, then, is the development of a unified analytical framework for studying such algorithms. This framework is built on our insight that when formulated as non-cooperative games, DCOPs form a subset of the class of potential games. This result allows us to prove convergence properties of iterative approximate best-response algorithms developed in the computer science literature using game-theoretic methods (which also shows that such algorithms can also be applied to the more general problem of finding Nash equilibria in potential games), and, conversely, also allows us to show that many game-theoretic algorithms can be used to solve DCOPs. By so doing, our framework can assist system designers by making the pros and cons of, and the synergies between, the various iterative approximate best-response DCOP algorithm components clear.

Active Steering Assistance for Lane Keeping and Lane Departure Prevention

Single-vehicle road departure accidents represent a substantial amount of today’s accidents. This paper presents the design and experimental test of an active steering assistance system that offers two functions: lane departure avoidance by temporary activation and maintaining vehicle heading by permanent activation. Each of the two functions can be used exclusively or in combination. Specific constraints related to each of the two functions are taken into account in the control design of the steering assistance by using LMI (linear matrix inequality) and BMI (bilinear matrix inequality) optimization methods. Consequently, lane overshoot is minimized for assistance activations near the border of the lane even during curve negotiation and robust lane keeping is ensured. Furthermore, the effects on lane keeping performance of simultaneous steering by the driver and the assistance are theoretically quantified. The results are verified using a fully equipped prototype vehicle. The obtained field test is consistent with the expected performance.

Simultaneous analysis of driver behaviour and road condition for driver distraction detection

The design of intelligent driver assistance systems is of increasing importance for the vehicle-producing industry and road-safety solutions. This article starts with a review of road-situation monitoring and driver's behaviour analysis. This article also discusses lane tracking using vision (or other) sensors, and the strength or weakness of different methods of driver behaviour analysis (e.g. iris or pupil status monitoring, and EEG spectrum analysis). This article focuses then on image analysis techniques and develops a multi-faceted approach in order to analyse driver's face and eye status via implementing a real-time AdaBoost cascade classifier with Haar-like features. The proposed method is tested in a research vehicle for driver distraction detection using a binocular camera. The developed algorithm is robust in detecting different types of driver distraction such as drowsiness, fatigue, drunk driving or the performance of secondary tasks.

Design and Control of a Power Assist System for Lifting Objects Based on Human Operator's Weight Perception and Load Force Characteristics

This paper deals with the design and control of a power assist system for lifting objects. It was hypothesized that an operator's perception of weight due to inertial force might be different from the perceived weight due to gravitational force. The system was simulated for different sizes of objects. Results show that an increase in mechanical time constant reduces perceived heaviness and load forces. The results also show the technique for simultaneous optimization of motion and perceived heaviness. Psychophysical studies show that the power assist system reduces the weights of the lifted objects to 40%, 30%, and 25% of the actual weights for unimanual, bimanual, and cooperative lifting tasks, respectively. The studies also show that operators apply 6.30, 6.22, and 6.14 times larger than the actually required load forces for the unimanual, bimanual, and cooperative lifting tasks, respectively. Therefore, a novel control strategy was proposed that reduced the excessive load forces and thus enhanced maneuverability, safety, naturalness, etc., of the system. The feasibility of zero gravity and zero inertia was studied. The operator's load force characteristics in some worst cases were studied. The effects of friction between an object and the operator's hand on weight perception and load forces were also studied. Power-assisted manipulation of objects in harmonic motion was also considered. Finally, it was proposed to use the findings to design power assist systems for lifting heavy objects in industries such as manufacturing, logistics, transport, construction, military and rescue operations, mining, etc., that would enhance interactions with human users.

Mathematical Modeling of the Human Cognitive System in Two Serial Processing Stages With Its Applications in Adaptive Workload-Management Systems

With the increasing usage of in-vehicle systems, drivers have to frequently perceive and respond to messages from these in-vehicle systems. In addition, previous studies have found that the interval between the messages (arrival rate) presented to a driver becomes one of the factors affecting driver workload. To reduce driver workload, researchers on adaptive workload-management systems have found that adding extra delay time into the interval of messages can significantly reduce driver workload. However, it is unknown whether this extra delay time added by an adaptive workload-management system will increase the performance time of drivers or not. To answer this important question, using closed-form mathematical equations, the current work quantifies human performance time (total task completion time and reaction time of each task) when there are two serial processing stages in the human cognitive system. The mathematical model developed in this work provides solutions of the optimal interval of messages that generate the lowest workload without deteriorating drivers' performance time to respond to multiple messages from in-vehicle systems. This is one of a few closed-form deterministic mathematical models with analytic solutions that can predict average reaction time when there are two multiple serial stages in the cognitive system in dual tasks. With relatively simple equations, the mathematical model can still capture the major patterns of simulation results with stochastic properties and human behavioral experimental results. The mathematical equations developed in this study can be used in the design of adaptive workload-management systems and other driver assistance systems.

An Assistance System Approach for Flexible Product Transport Operations in Process Plants

AbstractIn today's process industry, the computer-aided automation of engineering processes appears to have a great potential for helping to increase the efficiency of the production and to improve the quality of products, while lowering the costs of both the engineering and the reengineering of existing solutions. Nevertheless, this technique has the drawback of isolating qualified users from the execution of the system. In this paper we present an approach for an assistance system for the execution of product transport operations in complex pipeline networks. By using this approach, these operations can be accomplished semi-automatically – from task definition to final execution with field devices. The assistance system knows which part of the task can be automated and in which circumstances the user should be consulted in order to provide decision-making based on her/his experience. Such an approach can also be used as a guideline for the design of future assistance systems.

Design and efficiency measurement of cooperative driver assistance system based on wireless communication devices

In this paper, we participate to the effort of investigating the use of the inter-vehicle communication in order to increase safety on the roads. In order to fill the gap between the standardization work and the proposed services, our work aims at designing cooperative applications using an existent wireless technology. In this paper, we describe the communication architecture deployed on board our fleet of intelligent vehicles and based on 802.11 g+ devices. Using this architecture, we will prove the feasibility of cooperative services. Thus, we choose to study two situations of conflict on roads: crossroads approaching and lane changing manœuvre. For both scenarios, we analyze the contribution of our system for risk assessment and collision avoidance.

A vulnerability-centric requirements engineering framework: analyzing security attacks, countermeasures, and requirements based on vulnerabilities

Many security breaches occur because of exploitation of vulnerabilities within the system. Vulnerabilities are weaknesses in the requirements, design, and implementation, which attackers exploit to compromise the system. This paper proposes a methodological framework for security requirements elicitation and analysis centered on vulnerabilities. The framework offers modeling and analysis facilities to assist system designers in analyzing vulnerabilities and their effects on the system; identifying potential attackers and analyzing their behavior for compromising the system; and identifying and analyzing the countermeasures to protect the system. The framework proposes a qualitative goal model evaluation analysis for assessing the risks of vulnerabilities exploitation and analyzing the impact of countermeasures on such risks.

Development of a driver information and warning system with vehicle hardware-in-the-loop simulations

This paper presents a new method for the design and validation of advanced driver assistance systems (ADASs). With vehicle hardware-in-the-loop (VeHIL) simulations the development process, and more specifically the validation phase, of intelligent vehicles is carried out safer, cheaper, and more manageable. In the VeHIL laboratory a full-scale ADAS-equipped vehicle is set up in a hardware-in-the-loop simulation environment, where a chassis dynamometer is used to emulate the road interaction and where robot vehicles are used to represent other traffic. In this controlled environment the performance and dependability of an ADAS is tested to great accuracy and reliability. The working principle and the added value of VeHIL are demonstrated with test results of a driver information and warning system. Based on the ‘ V’ diagram, the position of VeHIL in the development process of ADASs is illustrated.

Factors correlated with traffic accidents as a basis for evaluating Advanced Driver Assistance Systems

This study aims to identify factors which influence and cause errors in traffic accidents and to use these as a basis for information to guide the application and design of driver assistance systems. A total of 474 accidents were examined in depth for this study by means of a psychological survey, data from accident reports, and technical reconstruction information. An error analysis was subsequently carried out, taking into account the driver, environment, and vehicle sub-systems. Results showed that all accidents were influenced by errors as a consequence of distraction and reduced activity. For crossroad accidents, there were further errors resulting from sight obstruction, masked stimuli, focus errors, and law infringements. Lane departure crashes were additionally caused by errors as a result of masked stimuli, law infringements, expectation errors as well as objective and action slips, while same direction accidents occurred additionally because of focus errors, expectation errors, and objective and action slips. Most accidents were influenced by multiple factors. There is a safety potential for Advanced Driver Assistance Systems (ADAS), which support the driver in information assimilation and help to avoid distraction and reduced activity. The design of the ADAS is dependent on the specific influencing factors of the accident type.