A First-Order Logic based Framework for Verifying Simulations

Modern science relies on simulation techniques for understanding phenomenon, exploring design options, or evaluating models. Assuring the correctness of simulators is a key problem where a multitude of solutions ranging from manual inspection to formal verification are applicable. Formal verification incorporates the rigor necessary but not all simulators are generated from formal specifications. Manual inspection is readily available but lacks the rigor and is prone to errors. In this paper, we describe an automated verification system (AVS) where the contraints that the system must adhere to are specified by the user in general purpose first-order logic. AVS translates these constraints into a verification program that scans the simulator trace and verifies that no constraints are violated. The advantage is the ability to verify any simulator trace using a formal specification of domain facts. Computer microarchitecture simulations were used to demonstrate the proposed approach. The system was implemented successfully to yield preliminary results

A Unifying Algorithm for Conditional, Probabilistic Planning

Several recent papers describe algorithms for generating conditional and/or probabilistic plans. In this paper, we synthesize this work, and present a unifying algorithm that incorporates and clarifies the main techniques that have been developed in the previous literature. Our algorithm decouples the search-control strategy for conditional and/or probabilistic planning from the underlying plan-refinement process. A similar decoupling has proven to be very useful in the analysis of classical planning algorithms, and we suspect it can be at least as useful here, where the search-control decisions are even more crucial. We describe an extension of conditional, probabilistic planning, to provide candidates for decision-theoretic assessment, and describe the reasoning about failed branches and side-effects that is needed for this purpose

Transgelin gene is frequently downregulated by promoter DNA hypermethylation in breast cancer

Tables not included in the main manuscript have been listed. Table S1. Number of probe sets affected by AZA treatment; Table S2. Comparison of significantly altered probe sets with the independent study GSE20713 Dataset; Table S3. Cancer vs. normal analysis of TAGLN mRNA in Oncomine database. (PDF 18 kb

Future engineers: leading the charge in the service sector

The demand for engineers to support the service sector is growing, and academic programs are needed to prepare students for these careers. This need was recognized at Michigan Tech and led to a dynamic effort by faculty members from different disciplines to develop a curriculum for Service Systems Engineering that integrates business, engineering, and the sciences and serves as a model for other universities. This is an exciting degree program that takes curriculum development beyond its current boundaries and branches into a new direction. In this paper, efforts related to the development of the curriculum will be described, as will the challenges faced by the project team to facilitate interdisciplinary education. The successes to date will be highlighted along with the lessons learned, and collaboration experiences with other university faculty members on curriculum development

Understanding labour productivity as an emergent property of individual and crew interactions on a construction site.”

ABSTRACT The construction site is a complex system composed of interactions in space between individual crewmembers and crews. Congestion often leads to lowered productivity. Lean construction research has shown that effective work flow management can improve construction labour performance, and labour flow contributes to lean work flow. The existing body of research in the study of construction labour productivity has primarily used a top-down approach to modelling and understanding the impacts of space congestion on labour productivity. In this paper, we propose a bottom-up approach and explore whether labour productivity on a construction site can be treated as an emergent property resulting from interactions between individual crewmembers and different crews. We present our pilot implementation and initial results depicting the relative value of various areas of space and the effect of the number of available tasks on congestion. KEY WORDS Agent Based Modelling, Productivity, Space Allocation INTRODUCTION Research in lean construction and the allied field of labour productivity has shown a strong dependence between work flows on a job-site and labour flow (Ballard and Howell 1998) and identified that variability in labour productivity can be reduced by appropriately matching labour resources to the available work to be performe

A hill-climbing approach for planning with temporal uncertainty

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Revisiting Partial-Order Probabilistic Planning

Abstract We present a partial-order probabilistic planning algorithm that adapts plan-graph based heuristics implemented in Repop. We describe our implemented planner, Reburidan, named after its predecessors Repop and Buridan. Reburidan uses plan-graph based heuristics to first generate a base plan. It then improves this plan using plan refinement heuristics based on the success probability of subgoals. Our initial experiments show that these heuristics are effective in improving Buridan significantly

Construction Management Applications: Challenges in Developing Execution Control Plans

The objective of automated planners is to synthesize sequences of actions (called policies in MDP frameworks) that will achieve a predetermined goal given a fully or partially observable formal representation of the domain. In contrast, the main characteristic of project management is the greater emphasis on plan execution under uncertainty as opposed to plan synthesis. This paper explains the need to transition from automated plan synthesis to plan management and identifies the challenges for the planning and scheduling communities using examples of construction projects

Verifying Micro-Architecture Simulators using Event Traces

Contemporary micro-architecture research inherently relies on cycleaccurate simulators to test new ideas. Typical simulator implementations involve tens of thousands of lines of high-level code. Although general software engineering verification and validation techniques can be applied, the mere complexity of simulators makes using formal techniques difficult and calls for domain-specific knowledge to be a part of the verification process. This domain-specific information includes modeling the pipeline stages and the timing behavior of instructions with respect to these stages. We present an approach to simulator verification that uses domainspecific information to effectively capture a potential mismatch between the assumed architecture model and its simulator. We first discuss how a simulator-generated event trace can be fed into an automatically generated verification program from a first-order logic specification to verify that the simulator obeys the invariants. We then show techniques that extract simulator behavior from traces and present the results to the user in the form of graphs and rules. While the former seeks an assurance of implementation correctness by checking that the model invariants hold, the latter attempts to derive an extended model of the implementation and hence enables a deeper understanding of what was implemented. Our techniques are applicable to any micro-architecture simulator. We present the application of our techniques to hand-written simulators as well as to those generated from an architecture specification language