An alignment-based framework to check the conformance of declarative process models and to preprocess event-log data

Process mining can be seen as the “missing link” between data mining and business process management. The lion's share of process mining research has been devoted to the discovery of procedural process models from event logs. However, often there are predefined constraints that (partially) describe the normative or expected process, e.g., “activity A should be followed by B” or “activities A and B should never be both executed”. A collection of such constraints is called a declarative process model. Although it is possible to discover such models based on event data, this paper focuses on aligning event logs and predefined declarative process models. Discrepancies between log and model are mediated such that observed log traces are related to paths in the model. The resulting alignments provide sophisticated diagnostics that pinpoint where deviations occur and how severe they are. Moreover, selected parts of the declarative process model can be used to clean and repair the event log before applying other process mining techniques. Our alignment-based approach for preprocessing and conformance checking using declarative process models has been implemented in ProM and has been evaluated using both synthetic logs and real-life logs from a Dutch hospital.     

基于线性时序逻辑理论的仓储机器人路径规划

首先根据仓储物流环境的特点构建了可灵活扩展的仓储环境模型,并制定了适合仓储物流需求的机器人运动规则,使该模型能够适用于动态的仓储物流环境;其次采用线性时序逻辑任务公式描述具体的任务需求,使其可以适用于实际应用中更加复杂的任务;继而将任务需求与环境信息相融合,构建任务可行网络拓扑,避免分段任务搜索;然后采用Dijkstra算法在任务可行网络拓扑上搜索出最优路径,确保规划所得路径的最优性;最后将任务可行网络拓扑上的最优路径映射回加权切换系统,获得环境中满足任务需求的最优路径。与目前广泛使用的A~*算法相比,上述方法不仅能够满足复杂的任务需求,而且能够保证路径规划的最优性,而不是次优解。     

Catalytic CO hydrogenation on potassic Fe/zeolite LTL

Zeolite LTL in the potassic form ( -LTL) was used as support of iron. The precursor was characterized by temperature programmed reduction (TPR) and Mössbauer spectroscopy (MS) at 298 and 15 K. The catalyst was obtained reducing the precursor with H₂ and its structural properties were studied by H₂ chemisorption, volumetric oxidation and MS under controlled conditions at 298 and 15 K. Measurements of activity and selectivity were carried out at 1 and 20 bar in the CO hydrogenation. Two different types of active sites were detected: Fe⁰ inside the zeolite channels and carburized iron on its external surface. The solid showed a high activity and selectivity towards light alkenes in comparison with other iron supported systems (Fe/SiO₂, Fe/Al₂O₃ and Fe/C). This behavior can be attributed to the high percentage of metallic iron promoted by potassium ions, located inside the zeolite channels. The external carbide crystals generate hydrocarbons in the diesel oil range.     

Model-based Runtime Verification Framework for Self-optimizing Systems

This paper describes a novel on-line model checking approach offered as service of a real-time operating system (RTOS). The verification system is intended especially for self-optimizing component-based real-time systems where self-optimization is performed by dynamically exchanging components. The verification is performed at the level of (RT-UML) models. The properties to be checked are expressed by RT-OCL terms where the underlying temporal logic is restricted to either time-annotated ACTL or LTL formulae. The on-line model checking runs interleaved with the execution of the component to be checked in a pipelined manner. The technique applied is based on on-the-fly model checking. More specifically for ACTL formulae this means on-the-fly solution of the NHORNSAT problem while in the case of LTL the emptiness checking method is applied.     

On Stubborn Sets in the Verification of Linear Time Temporal Properties

The stubborn set method is one of the methods that try to relieve the state space explosion problem that occurs in state space generation. This article is concentrated on the verification of next-time-less LTL (linear time temporal logic) formulas with the aid of the stubborn set method. The essential contribution is a theorem that gives us a way to utilize the structure of the checked formula when the stubborn set method is used and there is no fairness assumption. The theorem also applies to verification under fairness assumptions, including those which allow a predefined subset of actions to be treated unfairly.This work has been funded by the National Technology Agency of Finland, the Academy of Finland, Helsinki Graduate School in Computer Science and Engineering, Nokia Research Center, Nokia Networks, Elisa Communications, and Finnish Rail Administration.     

一种WS-BPEL流程的运行时监控方法

WS-BPEL作为一种web service组合语言,如今在企业解决方案中已经得到了广泛的应用.但是,由于WS-BPEL所依赖的外部服务的自治性以及流程本身的动态性和灵活性,其执行行为在运行前是不可预知的,流程的执行进行监控.本文提出了一种对WS-BPEL流程执行期进行动态监控的方法.该方法基于Past Linear Temporal Language (PLTL)描述监控规则,采用Aspect Oriented Programming(AOP)技术作为对BPEL引擎扩展监控功能的机制,从而实现对WS-BPEL流程实例的灵活有效监控.该方法在中国科学院软件研究所自主研发的OnceBPEL引擎上已经实现,能够满足灵活有效的监控需求.     

Catalytic coupling of propyne on Cu{111}

A novel analysis method of the platinum L₃ and L₂ X‐ray absorption edges of Pt/LTL catalysts indicates that chemisorbed hydrogen induces an antibonding resonance state just above the Fermi level at the Pt L₃ edge. The difference in energy of this antibonding state (E_res) with respect to the Fermi level is strongly influenced by the acidity/alkalinity of the LTL support: E_res decreases with increasing alkalinity. The decrease in E_res can also be correlated with the decrease of the neopentane hydrogenolysis turnover frequency of Pt/LTL with increasing support alkalinity. These results provide the most direct experimental evidence that the support acidity/alkalinity alters the actual chemical bond between the surface platinum atoms and the reacting molecule. This revised version was published online in July 2006 with corrections to the Cover Date.