Total project cost: a simplified model for decision makers

A simplified model for total project cost is developed in this paper to meet the numerous requests from decision makers for a model that can be used to estimate the total project cost from the estimated cash flows and, more importantly, to check the accuracy of the project cost estimates in feasibility studies that require prudent decisions. It begins with a base cost estimate in constant dollars and discrete cash flows with discrete inflation rates as practised by the construction industry. The discrete inflation rates are used to estimate the current dollar costs of the project. The effects of inflation are estimated as escalation during construction. Using the future value concept, interest during construction is estimated, in a simplified approach, to estimate the total project cost. Data from an actual feasibility study is used to highlight the strengths and weaknesses of the simplified model. The model is extended to treat discrete cash flows with continuous inflation rates.     

Estimating nutrient releases from agriculture in China: An extended substance flow analysis framework and a modeling tool

Agriculture related pollution has attracted the attention of policy makers as well as scientists in China as its contribution to water impairment has increased, and quantitative information at the national and regional levels is being sought to support decision making. However, traditional approaches are either time-consuming, expensive (e.g. national surveys) or oversimplified and crude (e.g. coefficient methods). Therefore, this study proposed an extended substance flow analysis (SFA) framework to estimate nutrient releases from agricultural and rural activities in China by depicting the nutrient flows in Chinese agro-ecosystems. The six-step process proposed herein includes: (a) system definition; (b) model development; (c) database development; (d) model validation; (e) results interpretation; and (f) uncertainty analysis. The developed Eubolism (Elementary Unit based nutrient Balance mOdeLIng in agro-ecoSysteM) model combined a nutrient balance module with an emission inventory module to quantify the nutrient flows in the agro-ecosystem. The model was validated and then applied to estimate the total agricultural nutrient loads, identify the contribution of different agricultural and rural activities and different land use types to the total loads, and analyze the spatial pattern of agricultural nutrient emissions in China. These results could provide an entire picture of agricultural pollution at the national level and be used to support policy making. Furthermore, uncertainties associated with the structure of the elementary units, spatial resolution, and inputs/parameters were also analyzed to evaluate the robustness of the model results.     

Welfare payments and migration in a nonlinear,extended input-output model with an application to Scotland

This paper examines an extended input-output model that includes a migration mechanism and a locally funded welfare benefit regime. The model is developed to include two regions. Two different solution methods of the model are discussed, one involving the introduction of nonlinearities into the input-output framework. The results of the two solutions are compared using test data for a one-region formulation, and data for a two-region division of Scotland. The regional impacts of varying unemployment benefits differentially are assessed, and a range of impacts of economic and demographic regional injections presented.     

Economic impacts of transportation network changes: Implementation of a combined transportation network and input-output model

This article estimates and evaluates the economic impacts from a catastrophic earthquake within regional and national contexts, emphasising the inter-industry relationship in conjunction with regional commodity flows and the assessment of seismic damages on a transportation network. The analytical methods employed are twofold: a multi-regional input-output model and a regional commodity flow model. Using the above analytical framework, the economic impacts from a catastrophic earthquake are estimated and evaluated based on hypothetical scenarios of the event, by analysing the magnitude and extent of direct and indirect impacts. Furthermore, as possible extensions, the models developed here can be used as tools for strategic management of the recovery and reconstruction efforts after the event. Received: 24 September 2000 / Accepted: 23 May 2001     

Estimation of nitrate reductase enzyme parameters in activated sludge using an extended Kalman filter algorithm

This paper demonstrates an application of the extended Kalman filter to a wastewater plant using real process data to estimate parameters in a semi-mechanistic model. This technique for parameter identification allows a semi-mechanistic model developed for pure cultures to be applied to a mixed culture population where isolation of enzyme kinetic parameters is not practical. This paper demonstrates an application in which a wastewater treatment facility with three physical unit operations and an unusual operating profile is modeled as 11 reactor units with recirculation streams. On-line nutrient probe data from two locations in the aerobic reactor are combined with operational data for flows and feed composition. This paper demonstrates the successful application of a biochemical model developed at the bench scale to this facility through the use of an extended Kalman filter. The estimated biological model parameters and the covariance matrix diagonal converge to stable values, indicating a successful implementation.     

A comparison of impact measures from hybrid and synthetic techniques: A case study of the Foothills Model Forest

This article presents an applied framework for selective precision in the insertion of superior data into hybrid regional models where regional purchasing coefficients are absent or unattainable. Due to the lack of regional-level data, crude top-down methods are the most frequently applied methods in Canadian regional studies. However, they may lead to inaccurate policy analysis where significant variation exists between the technical coefficients and trade flows of two economies. This article discusses an alternative, hybrid approach that involves the collection of region-specific information and therefore promises greater accuracy and validity of impact analysis. The robustness of the hybrid model is tested against the results derived from a synthetically regionalized model. The Foothills Model Forest (FMF) in west-central Alberta is used as a case study for the development of a sub-provincial economic database for the purpose of regional impact modeling. Received: September 1999/Accepted: September 2001     

Generating alternative designs for interjurisdictional natural resource development schemes in the Greater Ganges River basin

Planning for the development of regional water resources is often complicated by severe disputes. For example, in the Greater Ganges River basin, there are disagreements between India and Bangladesh over sharing the low river flows during the dry season and over controlling the potentially destructive large river flows during the monsoon. This paper illustrates an approach for providing the two riparian nations with distinct water resources plans to help solve their regional water conflicts. More specifically, a linear programming (LP) model representing a multipurpose river basin system is presented. The concept of near optimality is employed to generate a variety of solutions, in contrast to searching only for a global optimum. These solutions are grouped into similar project designs by applying a cluster analysis, which is a multivariate technique. Several project designs are graphically displayed, and their implications for national and international agreements are discussed. The range of regional alternatives available to India and Bangladesh could aid in their negotiations.An earlier version of this paper was presented at the 37th North American Meetings, Boston, November 1990.     

Regional adjustment and migration flows in Canada, 1971 to 1981

The primary purpose of this paper is to consider and test for various interlinkages between migration flows, and also between migration and employment change. Three types of migration flows are distinguished: domestic in-migration and outmigration, and net international migration. The three migration equations are embedded in a model of regional adjustment that also includes regional employment and wage changes as endogenous variables. The data base utilizes Canadian census statistics for 1971 and 1981 in a cross-section analysis with 183 regions represented by counties, or theri equavalents. The empirical performance of the various interlinkages is broadly in line with expectations, but the results raise some important questions about interpretation.     

A mathematical model for simulating spring discharge and estimating sinkhole porosity in a karst watershed

Documenting and understanding water balances in a karst watershed in which groundwater and surface water resources are strongly interconnected are important aspects for managing regional water resources. Assessing water balances in karst watersheds can be difficult, however, because karst watersheds are so very strongly affected by groundwater flows through solution conduits that are often connected to one or more sinkholes. In this paper we develop a mathematical model to approximate sinkhole porosity from discharge at a downstream spring. The model represents a combination of a traditional linear reservoir model with turbulent hydrodynamics in the solution conduit connecting the downstream spring with the upstream sinkhole, which allows for the simulation of spring discharges and estimation of sinkhole porosity. Noting that spring discharge is an integral of all aspects of water storage and flow, it is mainly dependent on the behavior of the karst aquifer as a whole and can be adequately simulated using the analytical model described in this paper. The model is advantageous in that it obviates the need for a sophisticated numerical model that is much more costly to calibrate and operate. The model is demonstrated using the St. Marks River Watershed in northwestern Florida.     

A general formula for the prediction of vent flows

A new formula for fire-induced wall vent flow rate is developed based upon a theoretical derivation and mathematical fit to data. Previous research had developed a formula of mass flow rate for fire-induced doorway flows only. Here it is extended to include window flows. A theoretical model based on an ideal point source fire plume is used to guide the form of the empirical correlation. A thorough examination concerning the difference between the window and doorway flow modes is conducted. Both sill height and width of the windows pose key influence on the formula. The two vent configurations are merged into one equation. The results were compared to available flow data and shown to be within 15% accuracy for a wide range of fire conditions.     

AN EXTENDED INPUT-OUTPUT MODEL INCORPORATING EMPLOYED, UNEMPLOYED, AND IN-MIGRANT HOUSEHOLDS

ABSTRACT Household disaggregation is an important, yet relatively neglected, factor in the construction of regional input-output models. This paper shows how a simple input-output model can he progressively extended to provide a more realistic representation or the relationship between industrial sectors anti demographic characteristics of a local labor market. An extended, model including employed, unemployed, and in-migrant households is proposed and its analytical properties examined. A detailed sensitivity analysis of this model is conducted, using data for Strathelyde in Scotland. Particular attention is given to establishing the range of parameter values that must be adhered in in order that economically feasible solutions may he obtained.     

The effects of fiscal equalisation in a model with endogenous regional governments: an analysis in a two-region numerical model

This paper is concerned primarily with the economic and welfare consequences of federal redistributive grants. We use a model which has two regions, each with households, firms and regional governments as well as a federal government. Private agents are (utility and profit) maximisers and we assume that regional governments are empire-builders in that they choose their expenditure and tax levels so as to maximise total expenditure—the size of their empire. Labour is free to move between regions in response to utility differences and does so until such differences have been eliminated. Inter-regional migration, inter-regional trade flows and federal government redistribution are the main sources of interconnectedness between the two regions. The model is linearised in log-differences and simulated using a calibration based on Australian state-level data. We find that the welfare effect of intergovernmental transfers is trivial but that all other variables of interest change substantially—consumption, employment, prices, taxes, wages, output and government expenditure. Finally, the signs of the effects of a federal transfer are not affected by the empire-building behaviour of regional governments although the magnitude of the effects is generally dampened.     

A FUZZY REGIONAL GROWTH MODEL TO CONTROL FOR REGIONAL INCOME DISPARITIES THAT ARISE IN A MODIFIED RAHMAN MODEL

ABSTRACT This paper reports on a first step towards controlling regional income disparities that arise in a modified Rahman model. The study is based on the use of the concept of fuzzy numbers from fuzzy set theory and the motions of an optimism and pessimistic optimal solution. A particular algorithm is advanced and detailed stimulations are discussed that focus on the controllability of the minimum share if investment. The fuzzy regional growth model codicils of a relatively easy to implement system with a fuzzy condition that can be extended to allow for a range of disparities in a system of regions.     

Efficient pricing for European electricity networks – The theory of nodal pricing applied to feeding-in wind in Germany

This paper applies nodal pricing as an economic approach to efficient use of electricity networks utilization for the fairly large German grid. We combine a straightforward welfare maximization with the technical specificities of electricity flows on a realistically large network. The nodal pricing model is applied in order to analyze the impact of extended German wind power production on the power grid. The paper shows that economic modeling, taking into account physical and technical constraints, makes important contributions to the assessment and optimization of system configuration and operation.     

Interregional analysis of energy flows

ABSTRACT The analysis of energy problems is limited by the lack of adequate statistics and instruments for energy analysis. The Commission of the European Communities, therefore, asked the Federal Statistical Office of the Federal Republic of Germany and the Ifo-Institute for Economic Research in Munich to establish input-output tables of energy flows. Relevant studies were simultaneously conducted in six other EEC countries (France, Italy, Belgium, Netherlands, United Kingdom and Denmark). This paper analyses the regional structure of energy flows in Europe. Empirical results are presented for the physical energy content (terajoule) and the energy costs (mill. DM) of commodities in France, Italy, Denmark, and the Federal Republic of Germany. In addition, it shows how mixed input-output systems in physical and value units can be analysed with the general input-output model. Mathematically, input-output analysis can be regarded as a special statement of a linear programming model; here, the customary quantity and price models of input-output analysis are transferred into a linear optimization model (general input-output model) with a substantial gain of information for users. The objective is to analyse regional differences in energy production and energy use within the European Communities.     

Labor migration amongst hierarchically competing and intervening origins and destinations

"A spatial interaction methodology is developed for modeling flows in a hierarchical system. A competing and intervening destinations framework is employed to model and predict U.S. state-to-state labor migration. This analysis is used to assess the importance of geographic variables in explaining variations in regional labor flows. Empirical findings suggest that U.S. labor migration is largely explained by...size, distance, locational accessibility, and intervening opportunities in a spatial hierarchy. It is also suggested that lagged migration or migrant stock is a product of the combined effect of these forces."     

INFERRING REGIONAL STRUCTURE FROM PARTIAL TRANSPORTATION FLOW DATA

ABSTRACT This paper modifies a doubly-constrained gravity model for use with incomplete, intercity flow data in a region where marginal trip totals are unknown. The model contains a new specification for the spatial separation term and uses dummy variables for balancing and trip-generation terms. From the data it infers regional structure in the form of trip-production and trip-altraction potentials. It also reveals demand elasticity with respect to variables describing the transportation system. The model is estimated with its uses are illustrated with 1933 rail-passenger traffic flows.     

Interregional labour migration and real wage disparities: Evidence from Japan

This paper empirically tests the relationships between interregional labour migration and regional real wages based on a multi-region economic geography model, which describes bilateral migration flows. In particular, this paper highlights real wage disparities in the migration analysis. Our empirical methodology contains two steps. First, we structurally estimate a gravity model using manufacturing workers’ migration flows across the 47 Japanese prefectures. Second, using the estimates of the structural parameters, we examine the impact of the real wage on the net migration rate. We find that migrants respond to real wage disparities, rather than to nominal wage disparities.     

The influence of modifications in a central heating system of a dwelling on the energy consumption,calculated with a dynamic model

An existing dynamic model of a dwelling has been extended with a model of a central heating system. Results of research regarding static and dynamic properties of boilers, radiators, convectors and thermostats have been used for this. With this mathematical model several design and operation strategies and their influence on the energy consumption and temperature in the living room have been studied. Application of a high-efficiency boiler instead of a conventional boiler in this example resulted in an energy saving of about 15%. Also, heating of only three rooms (living room, kitchen and bathroom), placing the boiler in the kitchen instead of the attic and reduction of the return-water temperature to 50 °C resulted in energy savings varying from 6% to 15%. In the last case, the temperature in the living room is about 1 °C lower because the dimensioning of the radiators was based on the usual water temperatures so that their capacity became too low.Improper distribution of the water over the radiators causes an increase of 10% in the energy consumption. Application of convectors and improper adjustment of the anticipator of the room thermostat both cause a 6% higher energy consumption. In the case of the convectors this is explained by the increased water flows and the reduced temperature drop over the convectors as compared with radiators.     

Eastern reforms,trade, and spatial change in the EU

Economic reforms in Eastern Europe and Eastern Europe's integration into the world economy are supposed to induce fundamental changes into European trade patterns. This will affect regions in the EU differently, depending on location and specialization. The article quantifies the impact of changing trade flows on EU regional manufacturing. Estimates are based on comparative static simulations, using an empirically calibrated computable partial equilibrium model of interregional trade. The spatial EU output pattern under status-quo conditions is compared with an optimistic “successful reform scenario”. The article explains the model structure and its calibration, and presents results for 13 manufacturing industries.