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Until now, identification of three‐dimensional non‐convex (concave) blocks has not been accomplished. However, a direct body concept, which is introduced here, can deal with both convex and concave blocks in the same process in connection with detection of individual blocks and computation of physical quantities. Thus, the dilemma in the generalization of identifying three‐dimensional multi‐block systems has been eliminated. The directed body concept used in geometrical identification problems makes it possible to build a novel automatic identification system for three‐dimensional multi‐block systems. This new system eliminates the time‐consuming work on geometrical identification, and copes with a variety of applications in multi‐body systems, such as rock masses.

This chapter provides basic knowledge on the principles used in modern signalling systems to ensure safe train separation and to establish safe routes through point zones. For train control, lineside signals are compared with cab signalling. For block protection, fixed block and moving block systems are covered. The described interlocking principles for routes leading through point zones include route locking and release, conflicting routes, flank protection, and overlaps. A section on automatic train protection explains the principles of how trains can be prevented from violating speed and authority limits. For this, an overview on the levels of the European Train Control System is provided. Some information is also given on train describers and automatic route setting systems to support traffic management in signalling centres.

Large sparse least-squares problems arise in different scientific disciplines such as optimization, data analysis, machine learning and simulation. This paper aims to propose a two-level hybrid direct-iterative scheme, based on novel block independent column reordering, for efficiently solving large sparse least-squares linear systems.

Herewith, a novel block column independent set reordering scheme is used to separate the columns in two groups: columns that are block independent and columns that are coupled. The permutation scheme leads to a two-level hierarchy. Using this two-level hierarchy, the solution of the least-squares linear system results in the solution of a reduced size Schur complement-type square linear system, using the preconditioned conjugate gradient (PCG) method as well as backward substitution using the upper triangular factor, computed through sparse Q-less QR factorization of the columns that are block independent. To improve the convergence behavior of the PCG method, the upper triangular factor, computed through sparse Q-less QR factorization of the coupled columns, is used as a preconditioner. Moreover, to further reduce the fill-in, then the column approximate minimum degree (COLAMD) algorithm is used to permute the block consisting of the coupled columns.

The memory requirements for solving large sparse least-squares linear systems are significantly reduced compared to Q-less QR decomposition of the original as well as the permuted problem with COLAMD. The memory requirements are reduced further by choosing to form larger blocks of independent columns. The convergence behavior of the iterative scheme is improved due to the chosen preconditioning scheme. The proposed scheme is inherently parallel due to the introduction of block independent column reordering.

The proposed scheme is a hybrid direct-iterative approach for solving sparse least squares linear systems based on the implicit computation of a two-level approximate pseudo-inverse matrix. Numerical results indicating the applicability and effectiveness of the proposed scheme are given.

A numerical model of deformable block systems that gives a unique solution for large displacement, large deformation and failure computations is presented. The forces acting on each block, from external loading or contact with other blocks, satisfy the equilibrium equations. Equilibrium is also achieved between external forces and the block stresses. Furthermore, the analysis fulfills constraints of no tension between blocks and no penetration of one block into another. Also, Coloumb's law is fulfilled at all contact positions for both static and dynamic computations. The program ready algorithms with brief derivations are stated in this paper.

Many physically challenged users cannot interact with a computer through a conventional keyboard and mouse. They may interact with a computer through one or two switches with the help of a scanning mechanism. In this paper we present a new scanning technique based on clustering screen objects and then compare it with two other scanning systems by using a simulator. The analysis shows that the best scanning system is a type of block scanning that divides the screen in four equal sized partitions for four iterations and then switches to eight‐directional scanning. However, with a more accurate target acquisition process, the cluster scanning technique is found to outperform other scanning systems.

This chapter examines the existing work on tangible user interfaces (TUIs) and focuses on tangible programming with the scope to enlighten the opportunities for innovation and entrepreneurship in this particular domain.

In the first section, we start by presenting in short the history of TUIs and then focus on tangible programming presenting the different design approaches. Then we present the opportunities for innovation and guidelines for future products.

In the second section, we review the entrepreneurial activities that combine educational toys and TUIs.

The main finding of this chapter is that although TUI design and research are still in its infancy and more design guidelines and research are required to further bridge the digital and the physical world, the first signs of entrepreneurship promise a bright future.

Limitations arise from the fact that many companies keep many of their financial data confidential. Thus, it was impossible to include and validate all the information that we intended to present.

Initially, this chapter motivates and challenges scientist to find novel innovative solutions in the field. Then, reveals the entrepreneurial opportunities and potential customers. Finally, shows the funding sources and how tangible products are offered in the market.

We propose a new kind of toys that might alter and expand science, technology, engineering, and mathematics (STEM) in education.

This chapter appears to be unique in the sense that is the first that reports simultaneously on TUIs, entrepreneurship, and innovation.

Deadlock is a rather undesirable phenomenon and must be well solved in flexible manufacturing systems (FMS). This paper aims to propose a general iterative deadlock control method for a class of generalized Petri nets (GPN), namely, G-systems, which can model an FMS with assembly and disassembly operations of multiple resource acquisition. When given an uncontrolled G-system prone to deadlocks, the work focuses on the synthesis of a near-optimal, non-blocking supervisor based on reachability graph (RG) analysis.

The concept of a global idle place (GIP) for an original uncontrolled G-system is presented. To simplify the RG computation of an uncontrolled G-system, a GIP is added temporarily to the net model during monitor computation steps. Starting with one token and then by gradually increasing the number of tokens in the GIP at each iteration step, the related net system is obtained. The minimal-covered-set of all bad markings of the related net system suffering from deadlock can be identified and then removed by additional monitors through an established place-invariant control method. Consequently, all related systems are live, and the GIP is finally removed when the non-blockingness of the controlled system is achieved. Meanwhile, the redundancy of monitors is also checked.

A typical G-system example is provided to demonstrate the applicability and effectiveness of the proposed method. Experiments show that the proposed method is easy to use and provides very high behavioral permissiveness for G-system. Generally, it can achieve an optimal or a near-optimal solution of the non-blocking supervisor.

In this work, the concept of GIP for G-systems is presented for synthesis non-blocking supervisors based on RG analysis. By using GIP, an effective deadlock control method is proposed. Generally, the proposed method can achieve an optimal or a near-optimal, non-blocking supervisor for an uncontrolled G-system prone to deadlocks.

The purpose of this paper is to present a hierarchical circuit synthesis system with a hybrid deterministic local optimization – multi‐objective genetic algorithm (DLO‐MOGA) optimization scheme for system‐level synthesis.

The use of a local optimization with a deterministic algorithm based on linear equations which is computationally efficient and improves the feasibility of designs, allows reduction in the number of MOGA generations required to achieve convergence.

This approach reduces the total number of simulation iterations required for optimization. Reduction in run time enables use of full transistor‐level models for simulation of critical system‐level sub‐blocks. Consequently, for system‐level synthesis, simulation accuracy is maintained. The approach is demonstrated for the design of pipeline analog‐to‐digital converters on a 0.35 μm process.

The use of a hybrid DLO‐MOGA optimization approach is a new approach to improve hierarchical circuit synthesis time while preserving accuracy.

This paper aims to be a think piece that promotes discussion around the design of coding toys for children. In particular, the authors examine three different toys that have some sort of block-based coding interface. The authors juxtapose three different design features and the demands they place on young children learning to code. To examine the toys, the authors apply a framework developed based on Gibson’s theory of affordances and Palmer’s external representations. The authors look specifically at the toys: interface design, intended play scenario and representational conventions for computational ideas.

As a research team, the authors have been playing with toys, observing their own children play with the toys and using them in kindergarten classrooms. In this paper, the authors reflect specifically on the design of the toys and the demands they place on children.

The authors make no claims about whether one toy/design approach is superior to another. However, the differences that the authors articulate should serve as a provocation for researchers and designers to be mindful about what demands and expectations they place on young children as they learn to code and use code to learn in any given system.

As mentioned above, the authors want to start a discussion about design of these toys and how they shape children's experience with coding.

There is a push to get coding and computational thinking into K-12, but there is not enough research on what this looks like in early childhood. Further, while research is starting to emerge on block-based programming vs text-based for older children and adults, little research has been done on the representational form of code for young children. The authors hope to start a discussion on design of coding toys for children.