The Unpublished Working Drawings for the Nineteenth-Century Restoration of the Double Structure of the Real Chiesa di San Lorenzo in Torino

In his church of San Lorenzo in Torino Guarino Guarini conceived a structural organism that transfers the weight of the dome to the foundations by means of a partially concealed ribbed structure. This rare example of architecture in which form and structure do not coincide is not the result of an eccentric choice of technical virtuosity, but rather a structure mechanism aimed at achieving certain effects that have been knowingly sought out by the architect.     

为了志同道合者

11月2日至8日,名为“UnfoldingLandscape”的中央美术学院设计学院毕业生作品震在伦敦苏富比画廊举行。这是作为中国酋席艺术学府的中央美术学院第一次在海外举行毕业生作品展,策展人布菜克本说：“一切都是为了志同道合者之间的分享。”     

Unfolding rules for GHC programs

This paper presents a set of rules for the transformation of GHC (Guarded Horn Clauses) programs based on unfolding. The proposed set of rules, called UR-set, is shown to preserve freedom from deadlock and to preserve the set of solutions to be derived. UR-set is expected to give a basis for various program transformations, especially partial evaluation of GHC programs.     

Unfolding semantics of graph transformation

Several attempts have been made of extending to graph grammars the unfolding semantics originally developed by Winskel for (safe) Petri nets, but only partial results were obtained. In this paper, we fully extend Winskel’s approach to single-pushout grammars providing them with a categorical concurrent semantics expressed as a coreflection between the category of (semi-weighted) graph grammars and the category of prime algebraic domains, which factorises through the category of occurrence grammars and the category of asymmetric event structures. For general, possibly nonsemi-weighted single-pushout grammars, we define an analogous functorial concurrent semantics, which, however, is not characterised as an adjunction. Similar results can be obtained for double-pushout graph grammars, under the assumptions that nodes are never deleted.     

An Improvement of McMillan's Unfolding Algorithm

McMillan has recently proposed a new technique to avoid the state explosion problem in the verification of systems modelled with finite-state Petri nets. The technique requires to construct a finite initial part of the unfolding of the net. McMillan's algorithm for this task may yield initial parts that are larger than necessary (exponentially larger in the worst case). We present a refinement of the algorithm which overcomes this problem.     

Optimized Topological Surgery for Unfolding 3D Meshes

Constructing a 3D papercraft model from its unfolding has been fun for both children and adults since we can reproduce virtual 3D models in the real world. However, facilitating the papercraft construction process is still a challenging problem, especially when the shape of the input model is complex in the sense that it has large variation in its surface curvature. This paper presents a new heuristic approach to unfolding 3D triangular meshes without any shape distortions, so that we can construct the 3D papercraft models through simple atomic operations for gluing boundary edges around the 2D unfoldings. Our approach is inspired by the concept of topological surgery, where the appearance of boundary edges of the unfolded closed surface can be encoded using a symbolic representation. To fully simplify the papercraft construction process, we developed a genetic‐based algorithm for unfolding the 3D mesh into a single connected patch in general, while optimizing the usage of the paper sheet and balance in the shape of that patch. Several examples together with user studies are included to demonstrate that the proposed approach works well for a broad range of 3D triangular meshes.     

Control of Safe Ordinary Petri Nets Using Unfolding

In this paper we deal with the problem of controlling a safe place/transition net so as to avoid a set of forbidden markings . We say that a given set of markings has property REACH if it is closed under the reachability operator. We assume that all transitions of the net are controllable and that the set of forbidden markings has the property REACH. The technique of unfolding is used to design a maximally permissive supervisor to solve this control problem. The supervisor takes the form of a set of control places to be added to the unfolding of the original net. The approach is also extended to the problem of preventing a larger set of impending forbidden marking. This is a superset of the forbidden markings that also includes all those markings from which—unless the supervisor blocks the plant—a marking in is inevitably reached in a finite number of steps. Finally, we consider the particular case in which the control objective is that of designing a maximally permissive supervisor for deadlock avoidance and we show that in this particular case our procedure can be efficiently implemented by means of linear algebraic techniques. Submitted to Discrete Event Dynamic Systems. A preliminary version of this paper titled “Control of safe ordinary Petri nets with marking specifications using unfolding,” was published in the Proc. IFAC WODES'04: 7th Work. on Discrete Event Systems (Reims, France), September 2004. Contact author is Alessandro Giua.     

3D Topology Preserving Flows for Viewpoint-Based Cortical Unfolding

We present a variational method for unfolding of the cortex based on a user-chosen point of view as an alternative to more traditional global flattening methods, which incur more distortion around the region of interest. Our approach involves three novel contributions. The first is an energy function and its corresponding gradient flow to measure the average visibility of a region of interest of a surface with respect to a given viewpoint. The second is an additional energy function and flow designed to preserve the 3D topology of the evolving surface. The third is a method that dramatically improves the computational speed of the 3D topology preservation approach by creating a tree structure of the 3D surface and using a recursion technique. Experiments results show that the proposed approach can successfully unfold highly convoluted surfaces such as the cortex while preserving their topology during the evolution.     

Petri网展开图法的分析和应用

Petri网的展开图是一种特殊的并发系统状态空间搜索方法，它不需要重复考虑并发事件的所有可能的交集，从而大大缩减状态空间爆炸给验证分析带来的空间复杂度和时间复杂度。使用展开图分析Petri网的行为属性与传统的Petri网分析方法相比，具有自己的特点。该文首先介绍了Petri网展开图的构造算法，在此基础上使用展开图分析方法对一个典型Petri网的活性，有界性和可逆性等行为属性进行了分析，并与传统的Petri网分析方法作比较。     

Unfolding Edges: Adding Context to Edges in Multivariate Graph Visualization

Existing work on visualizing multivariate graphs is primarily concerned with representing the attributes of nodes. Even though edges are the constitutive elements of networks, there have been only few attempts to visualize attributes of edges. In this work, we focus on the critical importance of edge attributes for interpreting network visualizations and building trust in the underlying data. We propose ‘unfolding of edges’ as an interactive approach to integrate multivariate edge attributes dynamically into existing node-link diagrams. Unfolding edges is an in-situ approach that gradually transforms basic links into detailed representations of the associated edge attributes. This approach extends focus+context, semantic zoom, and animated transitions for network visualizations to accommodate edge details on-demand without cluttering the overall graph layout. We explore the design space for the unfolding of edges, which covers aspects of making space for the unfolding, of actually representing the edge context, and of navigating between edges. To demonstrate the utility of our approach, we present two case studies in the context of historical network analysis and computational social science. For these, web-based prototypes were implemented based on which we conducted interviews with domain experts. The experts' feedback suggests that the proposed unfolding of edges is a useful tool for exploring rich edge information of multivariate graphs.     

Unfolding the privacy paradox among mobile social commerce users: a multi-mediation approach

Considering that privacy paradox is currently an underexplored research area, this study proposes a privacy paradox model to explain the reasons behind such phenomenon. Built upon the theoretical link of belief-intention-behaviour and the idea of multi-mediation, this study seeks to discover the relationship between concern for social media information privacy and usage intention, and the potential mediators that stand between such linkage. The results suggest that perceived mobility and social support do mediate the said linkage, and the model could reasonably explain usage intention, which surprisingly has a negative association with usage behaviour. Theoretical and practical implications are subsequently offered.