An Architectural Approach to Ensuring Consistency in Hierarchical Execution

Hierarchical task decomposition is a method used in many agent systems to organize agent knowledge. This work shows how the combination of a hierarchy and persistent assertions of knowledge can lead to difficulty in maintaining logical consistency in asserted knowledge. We explore the problematic consequences of persistent assumptions in the reasoning process and introduce novel potential solutions. Having implemented one of the possible solutions, Dynamic Hierarchical Justification, its effectiveness is demonstrated with an empirical analysis

Oak Persistence in Mediterranean Landscapes: The Combined Role of Management, Topography, and Wildfires

Mediterranean ecosystems have been shaped by a history of human and ecological disturbances. Understanding the dynamics of these social-ecological systems requires an understanding of how human and ecological factors interact. In this study, we assess the combined role of management practices and biophysical variables, i.e., wildfire and topography, to explain patterns of tree persistence in a cork oak (Quercus suber L.) landscape of southern Portugal. We used face-to-face interviews with landowners to identify the management practices and the incentives that motivated them. We used aerial photographs and a Geographic Information System (GIS) to classify vegetation patch-type transitions over a period of 45 years (1958-2002) and logistic regression to explain such changes based on management and biophysical factors. The best model explaining vegetation transitions leading to cork oak persistence in the landscape included both biophysical and management variables. Tree persistence was more likely to occur on steeper slopes, in the absence of wildfires, and in the absence of understory management. We identified ecological, ideological, and economical barriers that preclude oak persistence and that are important to consider in implementing efficient environmental policies for adequate conservation and reforestation programs of Mediterranean cork oak landscape

Scheduling with partial orders and a causal model

In an ongoing project at Honeywell SRC, we are constructing a prototype scheduling system for a NASA domain using the 'Time Map Manager' (TMM). The TMM representations are flexible enough to permit the representation of precedence constraints, metric constraints between activities, and constraints relative to a variety of references (e.g., Mission Elapsed Time vs. Mission Day). The TMM also supports a simple form of causal reasoning (projection), dynamic database updates, and monitoring specified database properties as changes occur over time. The greatest apparent advantage to using the TMM is the flexibility added to the scheduling process: schedules are constructed by a process of 'iterative refinement,' in which scheduling decisions correspond to constraining an activity either with respect to another activity or with respect to one time line. The schedule becomes more detailed as activities and constraints are added. Undoing a scheduling decision means removing a constraint, not removing an activity from a specified place on the time line. For example, we can move an activity around on the time line by deleting constraints and adding new ones

Japanese Monetary Policy during the Collapse of the Bubble Economy: A View of Policymaking under Uncertainty

Focusing on policymaking under uncertainty, we analyze the monetary policy of the Bank of Japan (BOJ) in the early 1990s, when the bubble economy collapsed. Conducting stochastic simulations with a large- scale macroeconomic model of the Japanese economy, we find that the BOJf s monetary policy at that time was essentially optimal under uncertainty about the policy multiplier. On the other hand, we also find that the BOJ's policy was not optimal under uncertainty about inflation dynamics, and that a more aggressive policy response than actually implemented would have been needed. Thus, optimal monetary policy differs greatly depending upon which type of uncertainty is emphasized. Taking into account the fact that overcoming deflation became an important issue from the latter 1990s, it is possible to argue that during the early 1990s the BOJ should have placed greater emphasis on uncertainty about inflation dynamics and implemented a more aggressive monetary policy. The result from a counterfactual simulation indicates that the inflation rate and the real growth rate would have been higher to some extent if the BOJ had implemented a more accommodative policy during the early 1990s. However, the simulation result also suggests that the effects would have been limited, and that an accommodative monetary policy itself would not have changed the overall image of the prolonged stagnation of the Japanese economy during the 1990s.Collapse of the bubble economy; Monetary policy; Uncertainty

Composing Aspects at Shared Join Points

Aspect-oriented languages provide means to superimpose aspectual behavior on a given set of join points. It is possible that not just a single, but several units of aspectual behavior need to be superimposed on the same join point. Aspects that specify the superimposition of these units are said to "share" the same join point. Such shared join points may give rise to issues such as\ud determining the exact execution order and the dependencies among the aspects. In this paper, we present a detailed analysis of the problem, and identify a set of requirements upon mechanisms for composing aspects at shared join points. To address the identified issues, we propose a general and declarative model for defining constraints upon the possible compositions of aspects at a shared join point. Finally, by using an extended notion of join points, we show how concrete aspectoriented programming languages, particularly AspectJ and Compose*, can adopt the proposed model

Analiza diagnostic a subsitemelor sistemului de management Diagnosis Analysis of the Sub-Sistems of Management System

The management system represents all the elements having an organizational, decisional, informational, and methodological character through the agency of whom the process of management is achieved with a view of attaining a maximum level of performance. The managerial machinery of a modern company has a systemic structure within which the interdependencies among the component elements determine the functioning mechanism of the management at all levels. Irrespective of company’s characteristics (profile, size, market position, etc.) the following components of the management system should be noticed: the decisional sub-system, the organizational sub-system, the methodological and managerial sub-system, and the informational sub-system. The paper deals with a profound diagnosis analysis of these sub-systems considering the case of a company which activates within the Romanian energetic industry. The decisional sub-system gathers all the decisions adopted and implemented within the company according to the established goals and to the managerial hierarchical configuration. Integrated within the methodology of managerial analysis of the company, the diagnosis analysis of the decisional sub-system has as a goal the knowledge of its components, namely of the decisions established by managers during a certain period, of the manner the authority within the company is structured, of the decisional tools employed as well as of the part played by the organisms of participative management. Organizational sub-system represents all organizational elements that provide the frame, the division, the combination, and the functionality of labor processes with a view of achieving envisaged goals. The data displayed by the organizational scheme, the organizational and functioning regulations, jobs responsibilities at the level of a machines building company have emphasized several aspects that represent the starting point of analyzing the two components of this management sub-system, namely formal organization and informal organization. Informational sub-system comprises a series of data, items of information, informational fluxes and circuits, procedures and means of approaching information meant to contribute to the settlement and achievement of the company’s goals. The analysis of the informational sub-system has in view the fact that its part is to provide the company’s inner needs of information and its quality depends on the level of development of the technologies of transmitting information. The methodological sub-system designates the group of systems (complex methods), methods, and techniques employed in conceiving and exerting managerial functions and relations within a company. The important mutations that take place within the internal and external environment of the companies determine the managerial team to employ systems, methods, and techniques characteristic to managerial activity that are continually up-dated.diagnosis analysis; management system; decisional sub-system, organizational sub-system; informational sub-system; methodological sub-system

Lessons Learned and Next Steps in Energy Efficiency Measurement and Attribution: Energy Savings, Net to Gross, Non-Energy Benefits, and Persistence of Energy Efficiency Behavior

This white paper examines four topics addressing evaluation, measurement, and attribution of direct and indirect effects to energy efficiency and behavioral programs: Estimates of program savings (gross); Net savings derivation through free ridership / net to gross analyses; Indirect non-energy benefits / impacts (e.g., comfort, convenience, emissions, jobs); and, Persistence of savings