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System Complexity (system + complexity)
Selected AbstractsSystem Complexity As a Measure of Safe Capacity for the Emergency DepartmentACADEMIC EMERGENCY MEDICINE, Issue 11 2006Daniel J. France PhD Objectives System complexity is introduced as a new measure of system state for the emergency department (ED). In its original form, the measure quantifies the uncertainty of demands on system resources. For application in the ED, the measure is being modified to quantify both workload and uncertainty to produce a single integrated measure of system state. Methods Complexity is quantified using an information-theoretic or entropic approach developed in manufacturing and operations research. In its original form, complexity is calculated on the basis of four system parameters: 1) the number of resources (clinicians and processing entities such as radiology and laboratory systems), 2) the number of possible work states for each resource, 3) the probability that a resource is in a particular work state, and 4) the probability of queue changes (i.e., where a queue is defined by the number of patients or patient orders being managed by a resource) during a specified time period. Results An example is presented to demonstrate how complexity is calculated and interpreted for a simple system composed of three resources (i.e., emergency physicians) managing varying patient loads. The example shows that variation in physician work states and patient queues produces different scores of complexity for each physician. It also illustrates how complexity and workload differ. Conclusions System complexity is a viable and technically feasible measurement for monitoring and managing surge capacity in the ED. [source] Optimised spreading code redistribution PAPR reduction technique for MC-CDMA systemsEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 5 2009Lin Yang Multicarrier code division multiple access (MC-CDMA) is one of the most promising techniques considered for future broadband mobile services. However, the high peak to average power ratio (PAPR) problem associated with MC-CDMA systems can significantly degrade the power efficiency at the transmitter. This paper proposes an efficient PAPR reduction technique for the downlink of MC-CDMA systems. It regards the order of the CDMA spreading codes as an extra degree of freedom and exploits it to effectively reduce the PAPR of the signal. The proposed technique requires only slight modification to the MC-CDMA base station and negligible complexity to the mobile terminals. Both lightly loaded and fully loaded systems are examined when using the orthogonal sets of Walsh,Hadamard (WH) and Golay complementary sequences (CSs). It will be demonstrated that the proposed technique achieves significant PAPR reduction with low system complexity at both transmitter and receiver. Copyright © 2009 John Wiley & Sons, Ltd. [source] Chaotic analysis of predictability versus knowledge discovery techniques: case study of the Polish stock marketEXPERT SYSTEMS, Issue 5 2002Hak Chun Increasing evidence over the past decade indicates that financial markets exhibit nonlinear dynamics in the form of chaotic behavior. Traditionally, the prediction of stock markets has relied on statistical methods including multivariate statistical methods, autoregressive integrated moving average models and autoregressive conditional heteroskedasticity models. In recent years, neural networks and other knowledge techniques have been applied extensively to the task of predicting financial variables. This paper examines the relationship between chaotic models and learning techniques. In particular, chaotic analysis indicates the upper limits of predictability for a time series. The learning techniques involve neural networks and case,based reasoning. The chaotic models take the form of R/S analysis to measure persistence in a time series, the correlation dimension to encapsulate system complexity, and Lyapunov exponents to indicate predictive horizons. The concepts are illustrated in the context of a major emerging market, namely the Polish stock market. [source] User involvement in developing mobile and temporarily interconnected systemsINFORMATION SYSTEMS JOURNAL, Issue 2 2010Ola Henfridsson Abstract Information systems (IS) research on user involvement has primarily theorized relationships between developers, managers and users in systems development. However, so far, marginal attention has been paid to differences in user involvement practices between information systems. This paper explores user involvement in developing mobile and temporarily interconnected systems (MTIS). We refer to MTIS as heterogeneous systems that rely on network technologies for increasing the ubiquity of information services for users on the move. Such systems are becoming increasingly important in leveraging, e.g. car infotainment, supply chain management and wireless e-commerce. With particular emphasis on the nature of MTIS and its implications for user involvement, the paper analyses the systems development process of an action research project. The findings suggest that user involvement practices need to be adapted to accommodate features of this class of systems. Being an early attempt to trace the implications of technology features such as use context switches and temporary system relationships, the paper contributes to the development of an updated theory of the user role in an era of increased system complexity and stakeholder ambiguity. [source] Adaptive coding and modulation scheme for satellite-UMTS TDD systems based on a photogrammetric channel estimation methodINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 1 2006Hsin-Piao Lin Abstract The conventional wireless communication systems are designed to overcome the worst-case channel, using the huge amount of redundant bits to assure communications performance and quality of services. Those systems cannot achieve the optimum spectrum and power efficiency. This paper presents an adaptive coding and modulation scheme used in the user terminals of the third-generation satellite communication system. A three-state photogrammetric channel estimation method is introduced for tracing the variations of large-scale environments. The mobile user terminal dynamically switches the suitable coding and modulation schemes according to the result of photogrammetric channel estimator in order to maximize the power efficiency and data throughput. The real measurement data were used to validate our proposed method. The results show that the proposed method not only reduces the system complexity, but also mitigates the power control requirements and increases the data throughput for the land mobile satellite personal communication systems. Copyright © 2006 John Wiley & Sons, Ltd. [source] Promoting evidence-based practices: the adoption of a prevention support system in community settingsJOURNAL OF COMMUNITY PSYCHOLOGY, Issue 5 2009Sarah B. Hunter Prevention support systems (PSSs) are designed to help communities implement evidence-based practices (EBPs). Little is known about the factors that influence their adoption. In this article, we examined adoption of a PSS for substance abuse prevention called Getting To Outcomes (GTO)® among staff in two community coalitions with varying levels of exposure to it over a 2-year period. A multistage regression model was used to determine the relative predictive power of organizational, innovation-related, and practitioner characteristics on adoption. Findings indicate that GTO adoption occurred through increased exposure, especially via staff training. Perceptions of the system's complexity moderated this effect. Individuals with high GTO exposure were less likely to adopt it if they perceived it as complex. Other organizational, innovation-related, and practitioner characteristics did not predict adoption. Results from this study are useful for understanding the factors associated with PSS adoption and suggest ways to increase their use in typical delivery settings. © 2009 Wiley Periodicals, Inc. [source] | ||||||||||