Misleading stars: what cannot be measured in the internet?

Traceroute measurements are one of the main instruments to shed light onto the structure and properties of today’s complex networks such as the Internet. This article studies the feasibility and infeasibility of inferring the network topology given traceroute data from a worst-case perspective, i.e., without any probabilistic assumptions on, e.g., the nodes’ degree distribution. We attend to a scenario where some of the routers are anonymous, and propose two fundamental axioms that model two basic assumptions on the traceroute data: (1) each trace corresponds to a real path in the network, and (2) the routing paths are at most a factor $1/\alpha $ off the shortest paths, for some parameter $\alpha \in (0,1]$ . In contrast to existing literature that focuses on the cardinality of the set of (often only minimal) inferrable topologies, we argue that a large number of possible topologies alone is often unproblematic, as long as the networks have a similar structure. We hence seek to characterize the set of topologies inferred with our axioms. We introduce the notion of star graphs whose colorings capture the differences among inferred topologies; it also allows us to construct inferred topologies explicitly. We find that in general, inferrable topologies can differ significantly in many important aspects, such as the nodes’ distances or the number of triangles. These negative results are complemented by a discussion of a scenario where the trace set is best possible, i.e., “complete”. It turns out that while some properties such as the node degrees are still hard to measure, a complete trace set can help to determine global properties such as the connectivity.     

Can eye movements be effectively measured to assess product design?: Gender differences should be considered

This study investigates the relationship between eye movements and user emotional response to product features using eighteen product images as stimuli. The stimuli are composed of unpleasant, neutral and pleasant images. Regarding the emotional design, gender difference could be a major factor that should be taken into consideration. A task-free eye-tracking experiment was conducted in which forty participants (20 males and 20 females, mean age = 35.6, SD = 6.38, range 21–48 years) looked at randomly displayed product images. The eye movements of participants were measured while viewing product images. After viewing stimuli, participants rated immediately their emotional response to the product images on a seven-point scale. The results revealed that stimuli category and gender difference, caused different variations in fixation count, fixation duration, pupil diameter, and hit ratio. For stimuli category, participants have larger fixation count, fixation duration, pupil diameter, and hit ratio in response to pleasant and neutral product images than unpleasant product images. For gender difference, the results indicated that females provided larger scores in fixation count and fixation duration, but a smaller score in hit ratio in all stimuli than that provided by males. However, the measurement of pupil diameter yielded different results. The results showed that females provided larger pupil diameter in pleasant and neutral product images but a smaller pupil diameter in unpleasant product images than that provided by males, which is consistent with the result of subjective ratings.Relevance to industryThese findings could enable industrial counselors, product designers, and academics to categorize emotional response that can be subsequently incorporated into final product design. An understanding of gender-based processing differences of product features is important to designers since it enables them to communicate with these different market segments and to produce effective products for each segment.     

Can eye-tracking data be measured to assess product design?: Visual attention mechanism should be considered

Eye tracking probes user's perception of real-time reaction to products, while conventional methods (i.e. interviews, focus group, questionnaires and so on) have generally failed because they depend on users' willingness and competency to describe how they feel when they are exposed to a product. Two tasks were designed to explore the indexes of eye movement that can reflect user experience of product, and analyse the attention captured by product attributes and goal-oriented. In task one, participants just browsed two smart phone pictures and evaluated the whole user experience. Binary choices were used in task two to ask participants to select the smart phone picture with higher user experience and then click the mouse. The results showed that in the browsing task, participants had shorter time to first fixation for the smart phone picture with higher level of user experience than the lower. And pupil dilated significantly when participants browse smart phone picture with lower level of user experience. In goal-oriented task, participants' attentions were dominated by visual perception of task driven, mainly reflected on longer fixation time and larger pupil diameter when looking at the smart phone with higher level of user experience. These results support the notion that we cannot assess product design just by several eye-movement indexes without considering the effects of visual attention mechanism.Relevance to industryThe appearance of product plays an important role to attract user's attention and stimulate their intention to experience. And vision is the main channel for users to obtain product information. Hence a thorough research on the inherent mechanism of vision perception can provide technical support for product designers, which in turn can attract more consumers to experience the product, even buy it. Moreover, the seller can find out the real buyers and predict their desired products by tracking user's eyes.     

3D reconstruction: Why should the accuracy always be presented in the pixel unit?

This paper analyses the error presentation of parallax-based techniques (mainly stereoscopy and structured light). They are usually presented using an absolute (mm) or a relative (%) scale. These results are hard to compare between different systems as they are system-dependent. This paper presents results using the pixel unit which avoids the influence of geometric parameters. Moreover it is apt at evaluating whether the system under-performs or is similar compared to theoretical accuracy.     

Barriers to plant transparency,barriers to plant rigidity — A sketch of the problems posed by the radical changes in work forms in the machine-building industry

This article deals with the contradiction which became prominent with new market requirements for more flexibility and qualified products, on the one hand, and increased automatisation and informatisation of production and work processes, on the other. The new situation forces companies, especially small batch production, machine factories with their still qualified work and organisation, to build up more flexibility to stabilize and reinforce their market power. But their very technical answer shows that this management-strategy can, and in many cases will, lead to the opposite: growing inflexibility. Regarding this problem from a political-theoretical perspective and less from an economic-emperical one, the extending technical autonomy of the production process makes feasible extensive technical control by management over the working process and over the workers, too. But unlimited use of technical control by the computer-systems will not lead to more flexibility, on the contrary it hinders it and in addition to this it will be confronted with a barrier of productive innovation coming from the shop floor. Considering this, the author ventures the thesis that: as long as human work is needed in production processes, self regulation and control can be taken out of the qualification of the workers and be moved out of the organisation only at the risk of inflexibility and at the price of loss of social productivity and innovation. In order to prevent this, more care must be taken by using and designing technology for the interfaces between man-machine-system: differentiate the differences among them and do not mix or even convert them. A productive system also controlled by the workers who work in and with the system, and not only by management, shows that the question of more flexibility, productivity and innovation is tightly woven with the internal power structure in the organisation.     

Application of the QFD as a design approach to ensure comfort in using hand tools: Can the design team complete the House of Quality appropriately?

Quality Function Deployment is proposed as an effective design method to integrate ergonomics needs and comfort into hand tool design because it explicitly addresses the translation of customer needs into engineering characteristics. A crucial step during QFD concerns the linking of engineering characteristics to customer needs in the House of Quality by the design team. It is generally assumed (looking at all the QFD success stories) that design teams can accurately predict the correlations between customer needs and engineering characteristics (also referred to as “Whats”/“Hows” correlations). This paper explicitly tests this assumption by comparing the “Whats”/“Hows” correlations estimated by a design team with those observed in a systematic user evaluation study, which has not been done before. Testing the assumption is important, because inaccurate estimates may lead to ergonomically ineffective (re)design of hand tools and a waste of company resources. Results revealed that the design team's correlation estimates were not as accurate as is generally assumed. Twenty-five percent of the estimates differed significantly with those observed in the user evaluation study. Thus, QFD is a useful method to assist design teams in designing ergonomically more comfortable hand tools, but only on the condition that the correlations between customer needs and engineering characteristics are validated, preferably by means of a systematic user evaluation study.     

Enablers and barriers to the use of ICT in primary schools in Turkey: A comparative study of 2005–2011

The purpose of this study was to reveal barriers encountered by Turkish primary school teachers in the integration of ICT, to propose potential enablers to overcome those barriers, and to compare the current status of ICT integration (in 2011) with the status of ICT integration in 2005. Part of the data for this comparison was gathered in 2005 as part of a doctoral study by Goktas (2006). A survey design was used to investigate the barriers and enablers. Data were collected from 1373 teachers from 52 schools in 39 provinces. The results indicate that ‘lack of hardware’, ‘lack of appropriate software materials’, ‘limitations of hardware’, ‘lack of in-service training’, and ‘lack of technical support’ were the most important barriers. The highest ranked enablers were ‘allocation of more budget’, ‘allocation of specific units for peer support’, ‘allocation of support offices and personnel for teachers’, and ‘offering higher quality pre-service training for ICT’. Other leading enablers were ‘supporting teachers to enable effective ICT use’, ‘having technology plans’, ‘offering higher quality and more quantity of in-service training’, and ‘designing appropriate course content/instructional programs’. Analysis of an independent t-test revealed that most barriers showed significant differences and most enablers showed moderate or low differences between teachers' perceptions of their situation in 2005 and in 2011.     

Probing the axioms of evolutionary algorithm design: Commentary on “On the mapping of genotype to phenotype in evolutionary algorithms” by Peter A. Whigham,Grant Dick,and James Maclaurin

Properties such as continuity, locality, and modularity may seem necessary when designing representations and variation operators for evolutionary algorithms, but a closer look at what happens when evolutionary algorithms perform well reveals counterexamples to such schemes. Moreover, these variational properties can themselves evolve in sufficiently complex open-ended systems. These properties of evolutionary algorithms remain very much open questions.     

Social intelligence design in online chat communication: a psychological study on the effects of “congestion”

Social intelligence design (SID) is an essential concept for constructing electronic communities or computer-supported communication systems which effectively support various intelligent activities. This study is focused on one example of such systems, that is, online chat for real-time computer-mediated communication. We examined various dimensions of human information processing in online chat sessions from both the cognitive and social perspectives within psychology. A key variable which affects the process of a chat session is what we call communication congestion. We regard this quality as characterizing online chat sessions and are experimentally exploring its effects on chat performance and cognition processing by participants. Results of this experimental study suggest that medium-density congestion with a relevant topic might activate communication, particularly for experienced participants. Based on our findings, we discuss some suggestions regarding future innovations for chat systems.

The role of users in interactive systems design: When computers are theatre,do we want the audience to write the script?

User participation in the design process may be an axiom of quality design but in the design of interactive, innovative computer systems, user participation may be neither feasible nor desirable. Here, user centred methodologies miss the point. If computers are a medium rather than a tool, then we need a new design paradigm that recognizes the difference between using a product and experiencing a show. In this paper the role of users in interactive systems design within the context of Multimedia product development is discussed. The main features of Multimedia product development are outlined through reference to an empirical study of two organizations and the role of users in the design process is discussed. Finally a different design paradigm is suggested.     

On the controllability of the parameterized state matrix in “a continuation approach to eigenvalue assignment” by Harris,DeCarlo and Richter

This paper will investigate the controllability properties for systems parameterized as in Harns et al. (1983, Automatica, 19, 551–555). It will be shown that for systems of low dimensions this parameterization must be done carefully to guarantee that the system is controllable over the parameterization. The controllability property is key to the algorithms developed in Lefebvre et al. (1985, Int. J. Control, 41, 1273–1292), Richter and DeCarlo (1984, IEEE Trans. Aut. Control, AC-29), Harris et al. (1983, Automatica, 19, 551–555), Richter et al. (1981, Proc. 1981 Joint Aut. Control Conf.), Harris and DeCarlo (1982, Purdue School of EE, TR-EE 82-11) and Sebok and DeCarlo (1984, Proc. Allerton Conf. Communication, Control and Computing).