Every child deserves bouncers

While it was Spike Lee who made sneakers inextricably bound up with pop culture in his 1989 film “Do the Right Thing”, the emergence of sneakers as the footwear of the cool kids would already happen in the early 60’s. The rubber basket shoes, Converse’s All Stars and Bata’s Super Bullets, became as legendary as the people who wore them. The BATA shoe factory, established in 1894 by the Czech entrepreneur Tomas Bata, grew quickly to become the world’s biggest shoe company. The severe division of the world after the second world war into first and second however, meant the division of the company as well. The Eastern branch was nationalised; The Western branch moved its headquarters to Toronto. While the first focused completely on the production of shoes for within the Soviet Union, the latter quickly reached towards new international markets, with two new factories being built per year at its height. One of these new factories, BATA 300, was built in 1962 in the newly independent nation of Congo. The production of rubber tennis and basketball shoes in Kinshasa seems to suggest that the company wanted to open up a new consumer market for their products in Africa as well. The Belgian contractor and family business Blaton-Aubert, who developed a ground-breaking prestressing system for concrete in the early 1940’s with the Ghent based professor Gustave Magnel , was active since early 1950’s in the Belgian Congo with the subsidiary company Compagnie Congolais de Constructions (CCC). With the end of Belgian reign in 1960 however, the Blatons had to find a way to reposition themselves on the newly independent Congolese market. The company actively searched for new opportunities, abroad but also within Congo (Smets, 2012, p.192). In 1962 they seized the opportunity and gave everything to win the important contract to build the new factory for the multinational shoe company. The experience with prestressed concrete they had gained in Belgium was used as the main argument in their promotional material (Brussel: aam, Fonds Blaton). The development of the Blaton-Magnel prestressing system gave the company serious credibility as one of the founding fathers of the building technique. A pioneering application of prestressed concrete in a building was the factory for the Union Cottonière (UCO) in Ghent built by Blaton , followed by the experiments in Charleroi of the Blaton-engineer Jacques Robin. It is the same (Blaton in-house) engineer who would use his body of knowledge for the BATA 300 building in the wholly different context of Congo. The case of the Bata 300-factory in Kinshasa allows us to reassess the architectural history of Congo by shifting our view from the obsession with style and form to a more inclusive perspective with attention for transnational flows of ideas, models and practices. By focusing mainly on the figure of the architect, architectural history research on 20th century building in Africa so far has indeed only touched upon a small part of the immense built production in the former Belgian colony and presented a rather narrow narrative on the topic. If in 1949 Pierre Wigny, the then Minister of colonies, declared that “tout le congo est un chantier”, we need to broaden our gaze and include these other players in our narratives to gain a more complete and profound understanding of Congo’s architectural history. Our approach of the case of the new Bata factory in Kinshasa, then is in tune with the emerging scholarship that views construction history not only as a way of bringing a more complex web of different actors to the fore (contractors, engineers, clients and construction workers), but also, in line with what the French architectural historian Antoine Picon already argued in 2006, to write an alternative cultural history of building in the Congo that goes beyond an exclusively as a history of technology. (Picon, 2006). If we are interested in investigating the transfer (and transformation) of modes of production in the realm of concrete technology in Congo’s (post)colonial context, then we are also interested which African consumers Bata was targeting with their fancy new shoes

Towards a socially adaptive digital playground

We are working towards a socially adaptive digital playground for children. To this end, we are looking into nonverbal synchrony and other social signals as a measure of social behaviour and into ways to alter game dynamics to trigger and inhibit certain social behaviours. Our first results indicate that we can indeed influence social behaviours in a digital playground by changing game dynamics. Furthermore, our first results show that we will be able to sense some of these social behaviours using only computer vision techniques. I propose an iterative method for working towards a socially adaptive digital playground

Deflection control of prestressed concrete elements considering uncertainties

Excessive deflections can affect serviceability e.g. by causing damage to connecting building components and resulting in problems related to drainage in roof slabs. The deflections of a reinforced or prestressed concrete structure are subject to change over time, among others due to creep and shrinkage of concrete and relaxation of the steel used for prestressing. This structural response can be predicted as a function of time using calculation models available in literature which incorporate methods to account for these time-dependent effects. The deflection of prestressed elements is the result of the application of external loads and the prestressing of the tendons, which are two opposing actions (with respect to deflections). The resulting total deflection of the concrete element is very sensitive to small changes to the input variables used during design. A design method for deflection control is proposed which limits the deflection during the lifespan of the elements by defining requirements for the prestressing arrangement accounting for parameter uncertainty. An example of a prestressed beam is given in which the deflection is optimized over its lifetime

A parametric study on buckling of R/C columns exposed to fire

Buckling of concrete columns is a major issue in fire design, since heating of the columns will result in loss of stiffness and strength in the outer concrete layers. In the Dutch concrete code NEN 6720 (NEN, 1995), a quasi-linear theory of elasticity (KLE) method is provided for columns at ambient temperature. However, no literature is available showing whether this method could be adopted for elevated temperatures. Hence, an efficient calculation tool is needed to validate the applicability of this method in case of fire. As a first step, a cross-sectional calculation tool is introduced to calculate interaction curves of columns at ambient temperature. Further, the interaction diagrams obtained with this numerical method as well as the stiffness method provided in (Eurocode, 2004) and the KLE method are compared. Then, an assumed formula in the KLE-method for the nominal stiffness calculation is discussed considering interaction curves of columns in case of an ISO 834 fire. Finally, parameters like the fire duration and the slenderness ratio are investigated

SHM strategy optimization and structural maintenance planning based on Bayesian joint modelling

In this contribution, an example is used to illustrate the application of Bayesian joint modelling in optimizing the SHM strategy and structural maintenance planning. The model parameters were evaluated first, using the Markov Chain Monte Carlo (MCMC) method. Then different parameters including expected SHM accuracy and risk acceptance criteria were investigated in order to give an insight on how the maintenance planning and life-cycle benefit are influenced. The optimal SHM strategy was then identified as the one that maximizes the benefit

Coactive Learning for Locally Optimal Problem Solving

Coactive learning is an online problem solving setting where the solutions provided by a solver are interactively improved by a domain expert, which in turn drives learning. In this paper we extend the study of coactive learning to problems where obtaining a globally optimal or near-optimal solution may be intractable or where an expert can only be expected to make small, local improvements to a candidate solution. The goal of learning in this new setting is to minimize the cost as measured by the expert effort over time. We first establish theoretical bounds on the average cost of the existing coactive Perceptron algorithm. In addition, we consider new online algorithms that use cost-sensitive and Passive-Aggressive (PA) updates, showing similar or improved theoretical bounds. We provide an empirical evaluation of the learners in various domains, which show that the Perceptron based algorithms are quite effective and that unlike the case for online classification, the PA algorithms do not yield significant performance gains.Comment: AAAI 2014 paper, including appendice

Classes of decision analysis

The ultimate task of an engineer consists of developing a consistent decision procedure for the planning, design, construction and use and management of a project. Moreover, the utility over the entire lifetime of the project should be maximized, considering requirements with respect to safety of individuals and the environment as specified in regulations. Due to the fact that the information with respect to design parameters is usually incomplete or uncertain, decisions are made under uncertainty. In order to cope with this, Bayesian statistical decision theory can be used to incorporate objective as well as subjective information (e.g. engineering judgement). In this factsheet, the decision tree is presented and answers are given for questions on how new data can be combined with prior probabilities that have been assigned, and whether it is beneficial or not to collect more information before the final decision is made. Decision making based on prior analysis and posterior analysis is briefly explained. Pre-posterior analysis is considered in more detail and the Value of Information (VoI) is defined

Parametric study of the load-bearing mechanisms in RC beam-grids to resist progressive collapse

Recently, several structural failures demonstrated the disastrous consequences of progressive collapse and raised the awareness of the engineering community. However the low probability of progressive collapse makes it uneconomical to design every building against progressive collapse using conventional design methods. Furthermore in most cases the initiating events of progressive collapses are unknown during the design. As such, consideration of secondary load-carrying mechanisms can be an effective alternative. These mechanisms include compressive arch action (CAA) and tensile catenary action (TCA) in reinforced concrete (RC) beams. Several researchers have investigated the effects of CAA and TCA experimentally and numerically in individual RC beams. However to date limited studies have been carried out to study these mechanisms in RC beam-grids. Hence in this contribution a validated numerical model is developed to study and quantify the individual contributions and development of the different mechanisms in RC beam-grids. Parametric studies are performed in relation to the influence of the aspect ratio of the grid, reinforcement ratio and ultimate reinforcement strain