Search methods for tile sets in patterned DNA self-assembly

The Pattern self-Assembly Tile set Synthesis (PATS) problem, which arises in the theory of structured DNA self-assembly, is to determine a set of coloured tiles that, starting from a bordering seed structure, self-assembles to a given rectangular colour pattern. The task of finding minimum-size tile sets is known to be NP-hard. We explore several complete and incomplete search techniques for finding minimal, or at least small, tile sets and also assess the reliability of the solutions obtained according to the kinetic Tile Assembly Model.     

Size-separable tile self-assembly: a tight bound for temperature-1 mismatch-free systems

We introduce a new property of tile self-assembly systems that we call size-separability. A system is size-separable if every terminal assembly is a constant factor larger than any intermediate assembly. Size-separability is motivated by the practical problem of filtering completed assemblies from a variety of incomplete “garbage” assemblies using gel electrophoresis or other mass-based filtering techniques. Here we prove that any system without cooperative bonding assembling a unique mismatch-free terminal assembly can be used to construct a size-separable system uniquely assembling the same shape. The proof achieves optimal scale factor, temperature, and tile types (within a factor of 2) for the size-separable system.     

Fixed-point tile sets and their applications

An aperiodic tile set was first constructed by R. Berger while proving the undecidability of the domino problem. It turned out that aperiodic tile sets appear in many fields, ranging from logic (the Entscheidungsproblem) to physics (quasicrystals). We present a new construction of an aperiodic tile set that is based on Kleene?s fixed-point construction instead of geometric arguments. This construction is similar to J. von Neumann?s self-reproducing automata; similar ideas were also used by P. Gács in the context of error-correcting computations. This construction is rather flexible, so it can be used in many ways. We show how it can be used to implement substitution rules, to construct strongly aperiodic tile sets (in which any tiling is far from any periodic tiling), to give a new proof for the undecidability of the domino problem and related results, to characterize effectively closed one-dimensional subshifts in terms of two-dimensional subshifts of finite type (an improvement of a result by M. Hochman), to construct a tile set that has only complex tilings, and to construct a “robust” aperiodic tile set that does not have periodic (or close to periodic) tilings even if we allow some (sparse enough) tiling errors. For the latter, we develop a hierarchical classification of points in random sets into islands of different ranks. Finally, we combine and modify our tools to prove our main result: There exists a tile set such that all tilings have high Kolmogorov complexity even if (sparse enough) tiling errors are allowed. Some of these results were included in the DLT extended abstract (Durand et al., 2008 [9]) and in the ICALP extended abstract (Durand et al., 2009 [10]).     

分子自组装的应用与计算机模拟研究进展

分子自组装技术已经在纳米技术、膜技术和生命科学等领域有广泛的应用。计算机模拟又是研究分子自组装特性、超分子聚集体结构和特性的有效方法。本文综述了分子自组装技术的应用情况,从热力学和动力学角度对近年分子自组装特性计算机模拟的研究进展进行了评述,最后分析了存在的一些问题并对今后的发展前景进行了展望。     

Structural elements of coordination mechanisms in collaborative planning processes and their assessment through maturity models: Application to a ceramic tile company

Maturity is defined as a measure to evaluate the capabilities of an organization in regards to a certain discipline. The Collaborative Planning Process is a very complex process and Coordination mechanisms are especially relevant in this field to align the plans of the supply chain members. The objective of this paper is to develop a maturity model and a methodology to perform assessment for the Structural Elements of Coordination Mechanisms in the Collaborative Planning Process. Structural elements are specified in order to characterize coordination mechanisms in a collaborative planning context and they have been defined as key areas to be assessed by the maturity model. The identified structural elements are: number of decision-makers, collaboration level, interdependence relationships nature, interdependence relationships type, number of coordination mechanisms, information exchanged, information processing, decision sequence characteristics and stopping criteria. Structural elements are assessed using the scheme of five levels: Initial, Repeatable, Defined, Managed and Optimized. This proposal has been applied to a ceramic tile company and the results are also reported.     

Agent-based simulation of competitive and collaborative mechanisms for mobile service chains

A new paradigm for a mobile service chain’s competitive and collaborative mechanism is proposed in this study. The main idea of the proposed approach is based on a multi-agent system with optimal profit of the pull, push, and collaborative models among the portal access service provider (PASP), the product service provider (PSP), and the mobile service provider (MSP). To address the running mechanism for the multi-agent system, an integrated system framework is proposed based on the agent evolution algorithm (AEA), which could resolve all these modes. To examine the feasibility of the framework, a prototype system based on Java-Repast is implemented. The simulation experiments show that this system can help decision makers take the appropriate strategies with higher profits. By analyzing the expectations and variances (or risks) of each player’s profit, the interaction between and among entities in the chain is well understood. It is found that in the situation where a collaborative mechanism is applied, the performance of players is better as compared to the other two situations where a competitive mechanism is implemented. If some constraints are applied, the risk will be kept at a low level.     

嵌段共聚物受限自组装结构的计算机模拟和理论预测

本文简述高分子自组装的几种计算机理论模拟方法.重点叙述用模拟方法去模拟和预测嵌段共聚物受限诱导自组装结构的情况.总结它们在一维、二维以及三维受限条件下自组装的理论预测和模拟的研究成果,并指出了在受限条件下自组装的研究中亟待解决的问题.     

Error sources and their impact on c-velocity methods

We propose an efficient method for detecting 3D planes from a moving uncalibrated camera. It assumes only a 3D translation for the egomotion. The original idea is to get around the dependence between the 2D motion field, the depth (i.e. scene structure) and the ignored egomotion. Relations are established between predicted iso-velocity curves and 3D surface parameters in eliminating the depth variable from equations. Surface assessment is performed within a simple velocity voting-space: a 3D surface, like a given plane, emerges as a curve, like a parabola. Experimentations validate our approach for several applications including automatic driver assistance, showing a surprising robustness. The aim of the present paper is to analyze this robustness. Five main perturbations are focused on and their influence on the plane detection process is studied in details.     

A simulation testbed for analyzing trust and reputation mechanisms in unreliable online markets

Modern online markets are becoming extremely dynamic, indirectly dictating the need for (semi-) autonomous approaches for constant monitoring and immediate action in order to satisfy one’s needs/preferences. In such open and versatile environments, software agents may be considered as a suitable metaphor for dealing with the increasing complexity of the problem. Additionally, trust and reputation have been recognized as key issues in online markets and many researchers have, in different perspectives, surveyed the related notions, mechanisms and models. Within the context of this work we present an adaptable, multivariate agent testbed for the simulation of open online markets and the study of various factors affecting the quality of the service consumed. This testbed, which we call Euphemus, is highly parameterized and can be easily customized to suit a particular application domain. It allows for building various market scenarios and analyzing interesting properties of e-commerce environments from a trust perspective. The architecture of Euphemus is presented and a number of well-known trust and reputation models are built with Euphemus, in order to show how the testbed can be used to apply and adapt models. Extensive experimentation has been performed in order to show how models behave in unreliable online markets, results are discussed and interesting conclusions are drawn.     

Architecture for modeling and simulation of technical systems along their lifecycle

Modeling and simulation is an established scientific and industrial method to support engineers in their work in all lifecycle phases—from first concepts or tender to operation and service—of a technical system. Due to the fact of increasing complexity of such systems, e.g. plants, cyber-physical systems and infrastructures, system simulation is rapidly gaining impact. In this paper, a simulation architecture is presented and discussed on three different industrial applications, which offers a client–server concept to master the challenges of a lifecycle spanning simulation framework. Looking ahead, open software concepts for modeling, simulation and optimization will be required to cover new co-simulation techniques and to realize distributed, for example web-based simulation environments and tools.     

射频仿真目标模拟系统误差分析及补偿

阐明了近场效应产生的原理,推导了二元定向公式,并对其进行了建模仿真,得出其对系统精度的影响程度.建立了阵面及转台回转中心关系的模型,利用模型推导了幅度误差和相位误差对目标位置精度的影响,然后对衰减器与移相器幅相漂移产生的原因进行了分析,并提出了各种误差的补偿办法.最后给出了系统误差产生的顺序.     

Approximation Error and Error Accumulation for the Landen Transform

In this note we derive explicit a priori error bounds for the approximation error and error accumulation of the descending Landen transform. Our results apply to incomplete elliptic integral of the first kind and give the framework to calculate error bounds in the representation of Jacobi's Zeta- and Theta-function.     

A simulation framework for measuring robustness of incentive mechanisms and its implementation in reputation systems

In game theoretical analysis of incentive mechanisms, all players are assumed to be rational. Since it is likely that mechanism participants in the real world may not be fully rational, such mechanisms may not work as effectively as in the idealized settings for which they were designed. Therefore, it is important to evaluate the robustness of incentive mechanisms against various types of agents with bounded rational behaviors. Such evaluations would provide us with the information needed to choose mechanisms with desired properties in real environments. In this article, we first propose a general robustness measure, inspired by research in evolutionary game theory, as the maximal percentage of invaders taking non-equilibrium strategies such that the agents sustain the desired equilibrium strategy. We then propose a simulation framework based on evolutionary dynamics to empirically evaluate the equilibrium robustness. The proposed simulation framework is validated by comparing the simulated results with the analytical predictions based on a modified simplex analysis approach. Finally, we implement the proposed simulation framework for evaluating the robustness of incentive mechanisms in reputation systems for electronic marketplaces. The results from the implementation show that the evaluated mechanisms have high robustness against a certain non-equilibrium strategy, but is vulnerable to another strategy, indicating the need for designing more robust incentive mechanisms for reputation management in e-marketplaces.     

Direct mail promotion mechanisms and their application in supermarkets

In this study, we consider the problem of selecting supermarket loyalty program members to receive physical direct mail and promotional electronic direct mail (i.e., direct email). To help marketers choose the target members for physical direct mails, we modify the customer’s preference index of our original model to predict members’ repurchase rates for a physical supermarket’s members. Based on members’ predicted repurchase rates, marketers can design proper marketing strategies for different types of supermarket member to improve marketing effectiveness. In addition, because members can only spend a short amount of time reading direct emails before choosing the products that they like, a recommender system based on a simple combination method is introduced. The system determines the most suitable combination of commodity types under the condition that a customized direct email can include only a small, fixed number of such types. In this study, member transaction records from a well-known Taiwanese supermarket were used as the test data. This supermarket’s marketing department reviewed all the experimental results and confirmed that our approach is not only superior to the current approach employed by the supermarket but also useful in designing appropriate direct-mail marketing strategies for selected supermarket members. Our approach is also suitable for direct email sent by the supermarket.

     

Destruction mechanisms of meteoroids and heat transfer to their surfaces

The phenomena of the movement and destruction of celestial bodies in the Earth’s atmosphere are investigated based on the advanced equations of meteor physics. The movement of meteorites in Kunya-Urgench (1998) and Chelyabinsk (2013) is analyzed as an example taking into account changes in the ablation along the trajectory. Different mechanisms of destruction of these meteorites are described.     

A comparison of refinement orderings and their associated simulation rules

In this paper we compare the refinement orderings, and their associated simulation rules, of state-based specification languages such as Z and Object-Z with the refinement orderings of event-based specification languages such as CSP. We prove with a simple counter-example that data refinement, established using the standard simulation rules for Z, does not imply failures refinement in CSP. This contradicts accepted results.Having explored the differences between the simulation rules for establishing data refinement and those for establishing the refinement of action systems and state-transition systems—models in which refinement is equivalent to failures refinement within CSP—we present a new set of simulation rules for data types. These alternative rules are both sound and jointly complete with respect to the stable failures refinement ordering. Furthermore we present an alternative refinement ordering for CSP, one in which refinement is equivalent to data refinement in Z.