Interaction between local and overall buckling

Numerical solutions of the equations governing the interaction of local and overall modes on box columns are presented. In confirmation of previous results these solutions show that elastic buckling is highly sensitive to changes in the magnitude of both local and overall small imperfections, and that the strong optimum indicated for coincident mode design is effectively eliminated when this imperfection sensitivity as well as effects of plasticity are included. It is also clearly demonstrated that the reduced modulus approach provides a conservative estimate of the elastic load-carrying capacity.The inclusion of plasticity into the analysis shows that the effects of elastic interaction may also be highly significant in controlling the plastic collapse load, and for most practical cases this plastic interactive buckling will control design. An extension of the Perry-Robertson procedure is shown to provide a convenient means of presenting the design information. Finally, the usefulness of the van der Neut model as the starting point of the analysis is verified.     

Use or disposal of by-products and spent material from the vegetable oil processing industry in Europe

The tendency in the oil and fat industry in Europe as far as by-products and spent material are concerned is to use and regenerate as much as possible for chemical-technical purposes. Materials with a high thermal value which are not suitable or profitable for use in chemical-technical products will in the future probably be utilized as a fuel in combination with fuel oil. By-products and spent material that cannot be exploited in the manners outlined above will be deposited in dumps. Incineration is another possibility. However, the quantities of waste must be of a considerable magnitude if this method is not to be too expensive.     

Embracing ambiguity in the design of non-stigmatizing digital technology for social interaction among senior citizens

In this paper we report our early experience with the design of technology for senior citizens. We take as our point of departure a pre-study of the ways in which older adult living occurs at three different senior housing facilities in southern Sweden. We contribute to the current debate concerning the ways in which digital technology can be designed to enable new types of living arrangements for the ever growing population of older people. We focus on technology designed to support the social rather than physical challenges of growing older. In particular we discuss how designing for social interaction can circumvent the stigma associated with being lonely in light of diminishing social networks, changed patterns of interactions with family, moving to a new neighbourhood, and the loss of a spouse. We will suggest that designers, in the design of digital technology for social interaction, deliberately leave room for ambiguity to make it possible for people to leave their intentions of use unarticulated. Furthermore, recognizing that many everyday activities already act as enablers for social interaction, we suggest utilizing such activities as an approach for design. We will support our suggestions by introducing three perspectives: a perspective emphasizing that the population of older adults is one of resourceful individuals; a perspective on social interaction emphasizing its circumstantial nature as an inherent part of everyday activities; and a perspective on the role of digital technology emphasizing its role as merely one of many resources present for human action. Finally, we will present an example concept showing how an enhanced TV remote control may be designed to enable social interactions without inflicting too much on the original experience of watching TV and most importantly, without stigmatizing the people using the remote control as lonely individuals craving the company of others.     

An Introduction to Adaptive QAM Modulation Schemes for Known and Predicted Channels

A major disadvantage with fixed modulation (nonadaptive) on channels with varying signal-to-noise ratio (SNR) is that the bit-error-rate (BER) probability performance is changing with the channel quality. Most applications require a certain maximum BER and there is normally no reason for providing a smaller BER than required. An adaptive modulation scheme, on the contrary, can be designed to have a BER which is constant for all channel SNRs. The spectral efficiency of the fixed modulation is constant, while it, in general, will increase with increasing channel SNRs for the adaptive scheme. This in effect means that the average spectral efficiency of the adaptive scheme is improved, while at the same time the BER is better suited to the requirement of the application. Thus, the adaptive link becomes much more efficient for data transmission. The major disadvantage is that the transmitter needs to know the channel SNR such that the best suitable modulation is chosen and the receiver must be informed on the used modulation in order to decode the information. This leads to an increased overhead in the system as compared with a fixed modulation system. In this paper, we introduce adaptive modulation systems by presenting some of the simpler adaptive quadrature amplitude modulation schemes and their performance for both perfectly known and predicted channels.     

REACTIVE TUNING OF TARGET ESTIMATE ACCURACY IN MULTISENSOR DATA FUSION

Dealing with conflicting and target-specific requirements is an important issue in multisensor and multitarget tracking. This paper aims to allocate sensing resources among various targets in reaction to individual information requests. The proposed approach is to introduce agents for every relevant target responsible for its tracking. Such agents are expected to bargain with each other for a division of resources. A bilateral negotiation model is established for resource allocation in two-target tracking. The applications of agent negotiation to target covariance tuning are illustrated together with simulation results presented. Moreover, we suggest a way of organizing simultaneous one-to-one negotiations, making our negotiation model still applicable in scenarios of tracking more than two targets.     

Economy and CO2 emissions trade-off: A systematic approach for optimizing investments in process integration measures under uncertainty

In this paper we present a systematic approach for taking into account the resulting CO₂ emissions reductions from investments in process integration measures in industry when optimizing those investments under economic uncertainty. The fact that many of the uncertainties affecting investment decisions are related to future CO₂ emissions targets and policies implies that a method for optimizing not only economic criteria, but also greenhouse gas reductions, will provide better information to base the decisions on, and possibly also result in a more robust solution. In the proposed approach we apply a model for optimization of decisions on energy efficiency investments under uncertainty and regard the decision problem as a multiobjective programming problem. The method is applied to a case of energy efficiency investments at a chemical pulp mill. The case study is used to illustrate that the proposed method provides a good framework for decision-making about energy efficiency measures when considerations regarding greenhouse gas reductions influence the decisions. We show that by setting up the problem as a multiobjective programming model and at the same time incorporating uncertainties, the trade-off between economic and environmental criteria is clearly illustrated.     

Optimized test circuits for SER characterization of a manufacturingprocess

Novel test circuits for the accurate determination of soft error rate (SER) dependency on critical charges Q_CRIT have been developed. The minimum charge necessary for flipping the state of a sensor cell, denoted by Q_CRIT, is measured with 1%-2% accuracy before exposing the circuits to radiation. During the accelerated testing, circuits biased with multiple different supply voltages V_CC are simultaneously placed into a beam and any bit flips are logged. From the measured SER dependency on V_CC and previously measured Q_CRIT dependency on V_CC, the dependency of SER on Q_CRIT can be deduced by correlating V_CC's for the two measurements. Furthermore, the sensor cell utilizes a single dynamic node which can be programmed to detect strikes on either N- or P-type diffusions, but not both at the same time. The measured dependency SER(Q_CRIT), normalized by the diffusion area, can be used for predicting SER of any other circuit fabricated in the same process and aid designers in optimization for reduced SER. Predictions of a theoretical SER model, if one is available, can be compared directly with the measurements. Since the true Q_CRIT of the test circuits is known accurately, any discrepancy larger than given by the measurement uncertainty of SER(Q_CRIT) would be clearly due to limitations of the SER model. We implemented the test circuits in a 0.6-μm bulk CMOS process and verified accuracy of Q_CRIT(V_CC) calibration method