Application Of Systems Analysis Techniques Research Articles

Application of a systems approach to problem analysis of African animal trypanosomiasis in the Gambia

The application of systems analysis techniques identified a number of key factors which will determine future developments in the Gambian livestock industry, with especial reference to traditionally managed trypanotolerant, N'dama cattle, and the importance of tsetse and trypanosomiasis. Different components of the analysis repeatedly identified the following key factors: human population growth; declining rainfall; loss of tree cover; trends in land-use including increased areas under cultivation, reduced fallowing and reduced access for grazing; livestock numbers; prices for groundnuts (the main cash crop) and cattle; and indicators of national wealth reflecting cash available to invest in livestock or to purchase livestock products. In many areas tsetse and trypanosomiasis appear to be in decline as a result of habitat destruction but they are likely to persist in others where trypanotolerant animals face a high risk of trypanosomiasis infection and active control may bring significant benefits. Several of the identified trends raise doubts concerning the long-term sustainability of traditional grazing on common land, although improved, intensive management strategies can do much to alleviate these problems.

Multicriteria methods in river basin planning – a case study

A large number of multicriteria decision making (MCDM) methods have been proposed in the past and applied to water resources planning. The development and application of systems analysis techniques to assist decision makers in evaluating project alternatives having more than one objective in river basin planning is of recent origin. In this paper an attempt is made to demonstrate the use of ELECTRE (ELimination and (Et) Choice Translating REality) I and ELECTRE-II techniques for water resources planning in one of the major river basins (Krishna river basin) of South India. The river basin consists of 8 reservoirs and a diversion work. Formulation of the problem is provided leading to an array of 27 alternative systems (different combinations of reservoirs with a minimum of three in each alternative) with 6 criteria related to: (i) irrigation, (ii) power production, (iii) drinking water, (iv) environmental quality; (v) floods and (vi) cost of the project. Out of the six criteria two, namely environmental quality and floods, are qualitative in nature. A set of best alternative systems with their partial ordering is obtained from ELECTRE-I, which forms the input for ELECTRE-II. Complete ordering of the reduced alternatives is achieved with ELECTRE-II. Sensitivity analysis shows that changing the weights assigned to each criterion has greater effect on the results than does changing the scales. However, neither effect is significant. Therefore it is recommended that ELECTRE-I be used for screening alternatives under consideration and ELECTRE-II for complete ordering of the reduced set.

Multicriteria methods in river basin planning — A case study

A large number of multicriteria decision making (MCDM) methods have been proposed in the past and applied to water resources planning. The development and application of systems analysis techniques to assist decision makers in evaluating project alternatives having more than one objective in river basin planning is of recent origin.In this paper an attempt is made to demonstrate the use of ELECTRE (ELimination and (Et) Choice Translating REality) I and ELECTRE-II techniques for water resources planning in one of the major river basins (Krishna river basin) of South India. The river basin consists of 8 reservoirs and a diversion work. Formulation of the problem is provided leading to an array of 27 alternative systems (different combinations of reservoirs with a minimum of three in each alternative) with 6 criteria related to: (i) irrigation, (ii) power production, (iii) drinking water, (iv) environmental quality; (v) floods and (vi) cost of the project. Out of the six criteria two, namely environmental quality and floods, are qualitative in nature. A set of best alternative systems with their partial ordering is obtained from ELECTRE-I, which forms the input for ELECTRE-II. Complete ordering of the reduced alternatives is achieved with ELECTRE-II. Sensitivity analysis shows that changing the weights assigned to each criterion has greater effect on the results than does changing the scales. However, neither effect is significant. Therefore it is recommended that ELECTRE-I be used for screening alternatives under consideration and ELECTRE-II for complete ordering of the reduced set.

The Frequency-Dependent Behavior of Cerebral Autoregulation

Abstract Cerebral autoregulation is a complex physiological process composed of both fast and slow components that may respond differently to different rates and patterns of blood pressure variation. To assess the temporal nature of autoregulation, transcranial Doppler velocity recordings of the middle cerebral artery obtained over prolonged periods were compared with blood pressure recordings in 5 patients without cerebral disease and in 13 patients with intracranial pathological changes. Correlations between the velocity and pressure wave forms at various frequencies of variation were measured with systems analysis techniques. Patients with aneurysmal subarachnoid hemorrhage had high correlations indicating pressure-dependent flow and impaired autoregulation. Patients without cerebral disease had significantly lower correlations (P<0.01), indicating intact autoregulation. Examples of increasing correlations and correlations at new frequencies emerging as the clinical condition worsened are given. These preliminary examples suggest that the application of systems analysis techniques to velocity and pressure data allow measurement of the temporal nature of cerebral autoregulation.

The frequency-dependent behavior of cerebral autoregulation

Cerebral autoregulation is a complex physiological process composed of both fast and slow components that may respond differently to different rates and patterns of blood pressure variation. To assess the temporal nature of autoregulation, transcranial Doppler velocity recordings of the middle cerebral artery obtained over prolonged periods were compared with blood pressure recordings in 5 patients without cerebral disease and in 13 patients with intracranial pathological changes. Correlations between the velocity and pressure wave forms at various frequencies of variation were measured with systems analysis techniques. Patients with aneurysmal subarachnoid hemorrhage had high correlations indicating pressure-dependent flow and impaired autoregulation. Patients without cerebral disease had significantly lower correlations (P less than 0.01), indicating intact autoregulation. Examples of increasing correlations and correlations at new frequencies emerging as the clinical condition worsened are given. These preliminary examples suggest that the application of systems analysis techniques to velocity and pressure data allow measurement of the temporal nature of cerebral autoregulation.

Application of Systems Analysis Techniques to Vulnerability Studies of Complex Installations

Vulnerability analysis provides an assessment of the likelihood of system failure in a man‐made hostile environment, involving sabotage, security compromise and combat damage. The fault‐tree approach proved most useful as many obscure but significant failure modes surfaced as a result of the step‐by‐step logic involved. Analysis tools were applied to the problems of nuclear reactor sabotage, space shuttle and combat system vulnerability. An increased qualitative understanding of system vulnerabilities, the effectiveness of counter‐measures and the ranking of scenarios by their attractiveness to saboteurs or other adversaries were the chief results of the work.

Application of Systems Analysis Techniques in Optimizing Gas Lift Installations

Systems analysis technqiues are applied to several well cases in order to optimize production rate and gas consumption of a continuous flow gas lift system. It is a procedure whereby various components, such as well capability, tubing size, flowline size, and separator pressure are analyzed in conjunction with the entire system in order to optimize the individual well or group of wells in a field. The solution point (node) can be taken anywhere in the system, but normally taken at the bottom or top of the well, and preferably both. Example problems will show the most logical manner to increase the flow rate, reduce the gas consumption, or both. A lowering of separator pressure to increase the flow rate may be a serious mistake. Examples will show that a more logical approach may be to increase the flowline size. In conclusion, all the individual components of a system must be analyzed in conjunction with the entire system for proper final analysis.

Preliminary results from a methodology study in the field of groundwater resources management

Increasing water demand, conflicts among utilizations, water-body pollution have given a considerable impulse to the application of systems analysis techniques also to the field of groundwater resources management. In line with this, some mathematical simulation and optimization models taking into account the various aspects of management have been prepared. The first of these models, known as IDROSIM, is actually a package including various flow models developed both for the problem of parameter identification (distribution of transmissivity and porosity parameters, etc.) and for the so called direct problem. The second model, called IASO, deals with modifications in water quality as a function of pollution from urban, industrial or agricultural sources. The third model, called IDROPROG, sets out to apply linear programming techniques to the aquifer in order to optimize water resource utilization. Finally, problems of combined management of both groundwater and surface water are investigated by means of a fourth model, dubbed IDRINTEGRO. All these models are currently being tested on a coastal aquifer extending over an area of 600 km 2 on the Ionian side of the Puglia region of Italy. This paper makes a comprehensive survey of the principles on which the models are based, and provides further details on the IDROSIM simulation model.

An application of systems analysis techniques to the study of reactor seismic safety

Systems analysis is being used in conjunction with structural analysis to study the conservatisms and to provide insights into aspects of reactor seismic safety. An event-tree/fault-tree model of a commercial nuclear power plant is being constructed to determine the probability of release and probabilities of system and component failures caused by possible seismic events. The event-tree/fault-tree model is evaluated using failure data generated by applying the response a component sees to the component's fragility function. The responses are calculated by a structural analysis code using earthquake time histories as forcing functions. The quantification of the event-tree/fault-tree model is done conditional on a given seismic event and the conditional probabilities thus calculated unconditioned by integrating the results over the seismic hazard curve. In this way, most of the dependencies between event failures resulting from the seismic event itself are removed making known fault-tree analysis quentification techniques applicable. The outputs from the computations will be used in sensitivity studies to determine the key calculations and variables involved in seismic analyses of nuclear power plants.

Computer models in sub-regional planning

Rhodes T. (1969) Computer models in sub-regional planning, Reg. Studies 3, 331–336. The application of systems analysis techniques to urban research and their exploitation through the use of larger, faster computers is likely to transform traditional approaches to land-use forecasting. There is no shortage of conceptual models for use in sub-regional planning: however, there are relatively few operational models available to practising planners, mainly because of the elaborate data requirements of most conceptual systems. Data availability has therefore been an important criterion in the design of two operational computer models for use in the preparation of a Structure Plan for South Hampshire—a macro model of regional population growth and a micro model for activities allocation within the region. The main body of the paper describes in some detail the design, output and data requirements of these models. Although of use initially in plan preparation, both models are seen as the core of a management inf...