Urban Living Labs (ULL) are advanced as an explicit form of intervention delivering sustainability goals for cities. Established at the boundaries between research, innovation and policy, ULL are intended to design, demonstrate and learn about the effects of urban interventions in real time. While rapidly growing as an empirical phenomenon, our understanding of the nature and purpose of ULL is still evolving. While much of the existing literature draws attention to the aims and workings of ULL, there have to date been fewer critical accounts that seek to understand their purpose and implications. In this paper, we suggest that transition studies and the literature on urban governance offer important insights that can enable us to address this gap.

This article analyzes the connectivity of multihop radio networks in a log-normal shadow fading environment. Assuming the nodes have equal transmission capabilities and are randomly distributed according to a homogeneous Poisson process, we give a tight lower bound for the minimum node density that is necessary to obtain an almost surely connected subnetwork on a bounded area of given size. We derive an explicit expression for this bound, compute it in a variety of scenarios, and verify its tightness by simulation. The numerical results can be used for the practical design and simulation of wireless sensor and ad hoc networks. In addition, they give insight into how fading affects the topology of multihop networks. It is explained why a high fading variance helps the network to become connected.

This paper analyzes the impact of beamforming antennas on the topological connectivity of multihop wireless networks. As a metric for the connectivity of the network, we use the percentage P (path) of nodes that are connected via a multihop path. We show that simple randomized beamforming -i.e., each node adjusts its main beam into a randomly chosen direction for transmission and reception -significantly improves P (path) compared to networks with omnidirectional antennas employing the same power and sensitivity. The study is performed using accurate, analytical antenna models for uniform linear and circular antenna arrays. Already small arrays with four antenna elements give high gains of P (path). These gains are achieved although the nodes' average number of neighbors does not necessarily increase.

The Productive Failure (PF) approach prompts students to attempt to solve a problem prior to instruction – at which point they typically fail. Yet, research on PF shows that students who are involved in problem solving prior to instruction gain more conceptual knowledge from the subsequent instruction compared to students who receive the instruction first. So far, there is no conclusive evidence, however, that the beneficial effects of PF are explained by the attempt to generate one’s own solutions prior to instruction. The literature on example-based learning suggests that observing someone else engaging in problem-solving attempts may be an equally effective means to prepare students for instruction. In an experimental study, we compared a PF condition, in which students were actively engaged in problem solving prior to instruction, to two example conditions, in which students either observed the complete problem-solving-and-failing process of another student engaging in PF or looked at the outcome of this process (i.e., another student’s failed solution attempts). Rather than worked examples of the correct solution procedure, the students observed examples of failed solution attempts. We found that students’ own problem solving was not superior to the two example conditions. In fact, students who observed the complete PF process even outperformed students who engaged in PF themselves. Additional analyses revealed that the students’ prior knowledge moderated this effect: While students who observed the complete PF process were able to take advantage of their prior knowledge to gain more conceptual knowledge from the subsequent instruction, prior knowledge did not affect students’ post-test performance in the PF condition.

Summary Studies on the productive failure (PF) approach have demonstrated that attempting to solve a problem prepares students more effectively for later instruction compared to observing failed problem‐solving attempts prior to instruction. However, the examples of failure used in these studies did not display the problem‐solving‐and‐failing process, which may have limited the preparatory effects. In this quasi‐experiment, we investigated whether observing someone else engaging in problem solving can prepare students for instruction, and whether examples that show the problem‐solving‐and ‐failing process are more effective than those that only show the outcome of this process. We also explored whether the perceived model–observer similarity had an impact on the effectiveness of observing examples of failure. The results showed that observing examples effectively prepares students for learning from instruction. However, observing the model's problem‐solving‐and‐failing process did not prepare students more effectively than merely looking at the outcome. Studying examples were more effective if model–observer similarity was high.