Recommendations for tool-handle material choice based on finite element analysis

Huge areas of work are still done manually and require the usages of different powered and non-powered hand tools. In order to increase the user performance, satisfaction, and lower the risk of acute and cumulative trauma disorders, several researchers have investigated the sizes and shapes of tool-handles. However, only a few authors have investigated tool-handles' materials for further optimising them. Therefore, as presented in this paper, we have utilised a finite-element method for simulating human fingertip whilst grasping tool-handles. We modelled and simulated steel and ethylene propylene diene monomer (EPDM) rubber as homogeneous tool-handle materials and two composites consisting of EPDM rubber and EPDM foam, and also EPDM rubber and PU foam. The simulated finger force was set to obtain characteristic contact pressures of 20 kPa, 40 kPa, 80 kPa, and 100 kPa. Numerical tests have shown that EPDM rubber lowers the contact pressure just slightly. On the other hand, both composites showed significant reduction in contact pressure that could lower the risks of acute and cumulative trauma disorders which are pressure-dependent. Based on the results, it is also evident that a composite containing PU foam with a more evident and flat plateau deformed less at lower strain rates and deformed more when the plateau was reached, in comparison to the composite with EPDM foam. It was shown that hyper-elastic foam materials, which take into account the non-linear behaviour of fingertip soft tissue, can lower the contact pressure whilst maintaining low deformation rate of the tool-handle material for maintaining sufficient rate of stability of the hand tool in the hands. Lower contact pressure also lowers the risk of acute and cumulative trauma disorders, and increases comfort whilst maintaining performance.     

A novel cryptoprocessor architecture for chained Merkle signature scheme

One-time signature schemes rely on hash functions and are, therefore, assumed to be resistant to attacks by quantum computers. These approaches inherently raise a key management problem, as the key pair can be used only for one message. That means, for one-time signature schemes to work, the sender must deliver the verification key together with the message and the signature. Upon reception, the receiver has to verify the authenticity of the verification key before verifying the signature itself. Hash-tree based solutions tackle this problem by basing the authenticity of a large number of verification keys on the authenticity of a root key. This approach, however, causes computation, communication, and storage overhead. Due to hardware acceleration, this paper proposes, for the first time, a processor architecture which boosts the performance of a one-time signature scheme without degrading memory usage and communication properties. This architecture realizes the chained Merkle signature scheme on the basis of Winternitz one-time signature scheme. All operations, i.e., key generation, signing, and verification are implemented on an FPGA platform, which acts as a coprocessor. Timing measurements on the prototype show a performance boost of at least one order of magnitude compared to an identical software solution.     

Service integrators in business networks—the importance of relationship values

To realise the potentials of CRM (customer relationship management), relationship-specific processes need to be designed and implemented in companies. This is all the more important and complicated in business networks where two or more actors collaborate to serve the customers. A good collaboration within business networks is the basis for understanding the customer process and identifying customer needs. But, even in these days of customer orientation, transaction orientation is still a matter of strong interest, and the following questions remain to be answered: What is the difference between relationship-oriented processes and transaction-oriented processes, and how can relationship-oriented processes be designed for a business network? The authors give first answers to both questions by using a systematic, goal-oriented specialisation of generic actions. To give an example, one relationship-oriented process will be designed and specified for a certain customer process in the course of this paper.     

An empirical examination of application frameworks success based on technology acceptance model

Framework-based development is currently regarded as one of the most promising software development approaches when it comes to improvements in lead time, productivity and quality. However, many frameworks and projects based on frameworks still report failures, which indicate that there are problems related to both frameworks technology and frameworks usage. The objective of our research was to examine the major drivers that have an impact on a framework’s acceptance and a framework’s success. We used the technology acceptance model (TAM) and Seddon’s information systems success model as our underlying theory. Data collected from an online survey of 389 active framework users was used to test hypothesized models. Data analysis was performed via structural equation modeling. Our findings support the post-adoption version of TAM and the relationship between continuous use and the successful use of systems, where more use also means more net benefits. We found that the successful use of frameworks is mainly dependent on two factors: continuous framework usage intention and the perceived usefulness of the framework. Several practical and theoretical implications can be foreseen including advances in framework development guidelines and insight into the relationship between the acceptance and success of frameworks.     

Convolutional solutions of partial difference equations

A significant part of the theory of one-dimensional linear shift-invariant systems is based on the concept of weighting function (or impulse response): the output is the convolution of the weighting function with the input. This paper introduces the concept of linear translation-invariant systems and uses this notion in studying impulse response, z-transforms, and transfer functions for multidimensional systems.     

Exploring multi-user interactions with dynamic NFC-displays

Near Field Communication (NFC) is an emerging technology for touch-based mobile interactions with single- and multi-tagged objects. Although the latter may allow for simultaneous and collaborative interactions, most prototypes were not designed for multiple users and were only evaluated with single-user interactions. In this paper, we investigate the design, usability and user experience of multi-user interactions on dynamic NFC-displays. These interactive surfaces use a grid of NFC-tags for the direct manipulation of projected application user interfaces. In two user studies with three prototypes for multi-user interaction, we evaluated the performance of dynamic NFC-displays, interactions among users and the interplay between mobile devices and large displays.     

Fuzzy gain-scheduling control of a gas-liquid separation plant implemented on a PLC

In the paper an approach to the non-linear control of a gas-liquid separation plant is presented. To solve the problem the fuzzy gain-scheduling method was used and implemented on a programmable logic controller (PLC). Velocity-based linearization approach was used for control system design and implementation for the first time in process control application. Emphasis was placed on the appropriate adaptation of the method and some important implementation issues. The algorithm was carefully designed and tested by using ordinary simulation, hardware-in-the-loop simulation, and experiments on the real plant. The results show that the proposed approach substantially improves the closed-loop performance of the plant.     

Gaussian process internal model control

Nonlinear modelling approaches such as neural networks, fuzzy models and multiple model networks have been proposed for model based control, to improve the poor transient response of adaptive control techniques. The quality of control is known to be strongly related to the accuracy of the model which represents the process. A Bayesian Gaussian process (GP) approach provides an analytic prediction of the model uncertainty, which makes the GP model an ideal candidate for model based control strategies. This article extends the use of the GP model for nonlinear internal model control. The invertibility of the GP model is discussed and the use of predicted variance is illustrated on a simulated example.     

Impact of Posttraumatic Stress Disorder on early smoking lapse and relapse during a self-guided quit attempt among community-recruited daily smokers

The present investigation examined whether daily smokers with posttraumatic stress disorder (PTSD), as compared to daily smokers with either anxiety psychopathology or no current Axis I psychopathology, have decreased success in the early phases of a self-guided smoking quit attempt. Participants were 140 daily smokers (81 women; M (age) = 29.5; SD = 11.9; range = 18-65 years); approximately one-third of the sample met criteria for current PTSD (n = 47), one-third met criteria for other current anxiety disorders (without PTSD; n = 33), and one-third did not meet criteria for any current Axis I disorder (n = 60). Consistent with prediction, membership in the PTSD group, compared to membership in the other anxiety disorders group and the group with no current Axis I psychopathology, was associated with increased risk of lapse during the first week following quit day. Additionally, daily smokers with PTSD and other anxiety disorders were at significantly increased risk of relapse during the first week post-cessation compared to persons without Axis I psychopathology. However, the PTSD group and the other anxiety disorders group did not differ from one another in terms of relapse. Results suggest that PTSD is associated with increased risk of smoking lapse and relapse compared to smokers with no current Axis I psychiatric problems, and increased risk of early smoking lapse but not relapse, as compared to those with other anxiety disorders. Findings provide novel evidence that PTSD, and perhaps anxiety disorders more generally, may be important factors in reducing the odds of successful unaided quit attempts in the early phases of cessation.