System-level Coordination Research Articles

Making Evaluations Work

This article describes the design and evaluation approaches to address the complexity posed by systems change initiatives. The role of evaluations in addressing the following issues is briefly reviewed: moving from strategic planning to implementation, impacts on system-level coordination, anticipated timeline of impact, and individual level impacts. The role of evaluations in enhancing multiple types of learning is also summarized.

Cooperative interference mitigation using fractional frequency reuse and intercell spatial demultiplexing

For mobile wireless systems with full frequency reuse, co-channel interference near the cell coverage boundaries has a significant impact on the signal reception performance. This paper addresses an approach to efficiently mitigate the effect of downlink co-channel interference when multi-antenna terminals are used in cellular environments, by proposing a signal detection strategy combined with a system-level coordination for dynamic frequency reuse. We demonstrate the utilization of multi-antennas to perform spatial demultiplexing of both the desired signal and interfering signals from adjacent cells results in significant improvement of spectral efficiency compared to the maximal ratio combining (MRC) performance, especially when an appropriate frequency reuse based on the traffic loading condition is coordinated among cells. Both analytic expressions for the capacity and experimental results using the adaptive modulation and coding (AMC) are used to confirm the performance gain. The robustness of the proposed scheme against varying operational conditions such as the channel estimation error and shadowing effects are also verified by simulation results.

Multi-Objective Pareto Concurrent Subspace Optimization for Multidisciplinary Design

Most real-world design problems are complex and multidisciplinary, with almost always more than one objective (cost) function to be extremized simultaneously. The primary goal of this research is to develop a framework to enable multi-objective optimization of multidisciplinary design applications, wherein each discipline is able to retain substantial autonomous control during the process. To achieve this end, we have extended the capability of the concurrent subspace optimization method to handle multi-objective optimization problems in a multidisciplinary design optimization context Although the conventional concurrent subspace optimization approach is easily able to deal with multi-objective optimization problems by applying the weighted sum approach, the main disadvantage is that the weighted sum cannot capture Pareto points on any nonconvex part of the Pareto frontier. Moreover, an aggregate objective function simply cannot reflect the true spirit of the concurrent subspace optimization method, which was developed to allow groups of specialists to independently have more control over their own design criteria and goals, even while maintaining system level coordination. In this paper, the multi-objective Pareto concurrent subspace optimization method is proposed in which each discipline has substantial control over its own objective function during the design process, while still ensuring responsibility for constraint satisfaction in coupled subspaces. The proposed approach is particularly useful given the realities of geographical distribution, computational platform variation, and dependence upon legacy codes within individual disciplines that so predominates the design of large-scale products such as aircraft and automobiles. As part of the multi-objective Pareto concurrent subspace optimization method developed here, it is demonstrated that the endpoints of the Pareto frontier can be easily identified, together with an ability to generate Pareto points within prescribed limits to ensure a reasonably even distribution across the entire frontier. The approach is validated (using three multidisciplinary design optimization test problems) against Pareto frontiers generated using the weighted sum approach.

분야별 하부시스템의 최적화를 통합한 분해기반 MDO 방법론

The paper describes the development of a decomposition based multidisciplinary design optimization (MDO)method that coordinates each of disciplinary subspace optimization (DSO). A multidisciplinary design system considered in the present study is decomposed into a number of subspaces based on their own design objective and constraints associated with engineering discipline. The coupled relations among subspaces are identified by interdisciplinary design variables. Each of subsystem level optimization, that is DSO would be performed in parallel, and the system level coordination is determined by the first order optimal sensitivities of subspace objective functions with respect to interdisciplinary design variables. The central of the present work resides on the formulation of system level coordination strategy and its capability in decomposition based MDO. A fluid-structure coupled design problem is explored as a test-bed to support the proposed MDO method.

Mental Health in Head Start: New Directions for the Twenty-First Century

This article has two aims: to explore the historical reasons why mental health has been a contested issue in Head Start, and to describe areas of challenge and innovation which might further the program's goal of improving the well-being of parents and children in poverty. The historical sources of silence in the program concerning mental health issues are noted, and recent efforts to bring mental health closer to the center of the Head Start agenda described. Four areas of challenge which are crucial in improving mental health in Head Start, are then reviewed: definitional issues at the individual and family levels, program-level consultation and services, system-level coordination, and macro-level policy changes. In each section, the nature of the challenge, current innovative practices in response to the challenge, and recommendations for further action are discussed. A concluding section presents a summary of recommendations for both program practice and research.

Decategorizing health services: interim findings from the Robert Wood Johnson Foundation's Child Health Initiative.

Although results from the evaluation are preliminary thus far, certain tentative conclusions can be reached. First, both care coordination on a small scale and the production of community health report cards are achievable within the relatively short life of a foundation grant. Moreover, both efforts can result in tangible improvements for children and their families. Report cards associated with the initiative have made children's issues more prominent and appear to have led many community leaders to focus greater attention on children's needs. Likewise, many of the care coordination systems developed under the initiative have produced real change for children and their families by guiding them to needed health care and other services. It is important, however, to keep these accomplishments in perspective. While of significant benefit to demonstration communities, the monitoring and care coordination components of this initiative are not unique. A large number of communities have adopted monitoring and reporting programs in recent years. Similarly, care coordination efforts are well established in many communities. What is unique about the RWJF initiative is its attempt at decategorization, and much less progress has been demonstrated for this component. The less-than-hoped-for progress in implementing decategorization at the original sites appears to be the product of a number of interrelated factors. These include an absence of existing models and appropriate technical assistance; political difficulties in gaining cooperation from multiple local agencies involved in service provision; limited progress in establishing needed connections with the state and federal agencies that have authority over categorical programs; and difficulties in implementing major programatic changes when the health care system itself is undergoing rapid change. In combination, these barriers have proven to be largely insurmountable for the originally funded sites, although it is too early in the project to determine which of these factors is predominantly responsible for the lack of success. Whether the newer sites can learn from the experience of the first group and adapt strategies to overcome the multiple hurdles involved remains to be seen. Decategorization is a tool that has the potential to rationalize a fragmented service system by facilitating the coordination of services, especially for children and families with multiple needs. The need for decategorization of funds will not disappear, even if the federal government chooses to combine more of its grant programs to the states into block grants.(ABSTRACT TRUNCATED AT 400 WORDS)

A coordination structure approach to the management of projects

The paper uses object based models to capture and make visible the system level coordination structure of complex projects. These models facilitate the development of a shared view necessary for effective project management. In the paper, development and use of the models are illustrated using examples drawn from the design of custom silicon. We examine three custom silicon design projects to identify the significant coordination problems encountered as well as the difficulties of using activity based project management tools. Then we develop object based models of coordination structure as a tool to overcome these difficulties. We use these models to capture a project manager's view of the four stages of the custom silicon design cycle: design definition, chip design, prototype manufacture, and system integration. We conclude by discussing the relationship between the coordination structure approach and other project management tools, and the managerial advantages of the proposed approach in the management of complex projects. The approach has particular value for the management of projects in which the task structure is complex, uncertain, and unstable, as is typically the case in new product development. >

Integrated controls-structures optimization of a large space structure

The next generation of large space structure (LSS) will undoubtedly be characterized by high flexibility and low inherent damping and will benefit from integrated controls-structures (C–S) optimization. New methods are required to optimize these LSS for low weight and low power consumption while meeting operational and safety requirements. There is great interest in C–S optimization, but most research has focused on problems with simple models and simplified constraints implemented using special purpose software. The present research is significant because it uses general purpose control and structural analysis codes, is applied to a large, detailed structural model and includes objective and constraint functions derived from actual design specifications. Structural design variables are truss member sizes, material properties and spacecraft dimensions. Control design variables are gains. The approach is to divide the problem into a structural optimization step, a controls optimization step and a system level coordination step. The objective is to minimize mass and power consumption with constraints on strength, vibration characteristics and damping. This decomposition and optimization approach significantly improves the design of a structure based on the COFS-I Mast Flight System, which is chosen as a demonstration problem.