3,026 research outputs found
A World Trade Model with Bilateral Trade Based on Comparative Advantage
This paper describes an extension of Duchin's World Trade Model to include the explicit representation of transportation costs, permitting the endogenous determination of bilateral trade °ree;ows and region-specific prices. The original model is a linear program that, based on comparative advantage and the minimization of factor use, determines regional production and trade °ree;ows as well as world prices and scarcity rents for m regions, n goods, s transportation sectors, and k factors. The new World Trade Model with Bilateral Trade achieves its objectives by introducing transportation services and geographically dependent transportation requirements for each traded good and each pair of potential trade partners. The formulation of this model and its major properties are presented, and results from a preliminary analysis with 11 regions, 8 goods, 4 transportation sectors, and 6 factors of production are reported and compared with corresponding results from the World Trade Model.
Wage bargaining and political strength in the public sector
This paper analysis the link between political strength and public sector wages using a unique
matched individual-employer data set for Norwegian local governments during the period
1990-1998. The results indicate that political strength, measured in several ways, has a
positive effect on wages, while administrative strength, measured by the tenure of the chief
executive, has a negative effect. The positive effect of political strength is consistent with a
model in which the budgetary process is a multistage game and employment is determined in
an interaction with interest groups prior to the wage bargain
Shifting Trade Patterns as a Means to Reduce Global CO2 Emissions: Implications for the Aluminium Industry
This paper investigates how changes in the international division of labor can contribute to reducing CO2 emissions. The mitigation potential and costs implied by this mechanism are analyzed. Implications for the aluminium sector are assessed, including changes in the price of aluminium when global carbon emissions are constrained and the constraints are progressively tightened. The analysis makes use of the World Trade Model with Bilateral Trade (WTMBT), a linear program based on comparative advantage with any number of goods, factors, and regional trade partners. Minimizing factor use, WTMBT determines regional production, bilateral trade patterns, and region-specific prices. The model is extended for this study through the application of multi-objective optimization techniques and is used to explore efficient trade-offs between reducing CO2 emissions and increasing global factor costs. This application demonstrates how the WTMBT, with its global scope and regional and sectoral production detail, can be used to build bridges between global objectives and concerns about a specific industry in specific regions. This capability can extend the reach of more traditional studies in industrial ecology.
Applying lean principles and set-based approaches in product development
The research described in this thesis addresses the problem of transformation to lean product development (LPD) and how to introduce and support the use of set-based design (SBD) in the concept development process. The original description of SBD does not define how to generate, evaluate and reduce a set of design solutions. Evaluation of solution candidates, which are too complex to be analytically verified, or are driven by qualitative criteria, has here been given special attention, particularly in cases when methods utilising human judgment may be needed. For some products, the solution space can consist of both principally different alternatives and parameterised variants of these. The question here is if established methods can be combined and introduced in an efficient way to support an SBD process for development of such products, when driven by both quantitative and qualitative criteria.The research approaches used are:-\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 a two-case study (Yin, 2009), -\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 the design research methodology (Blessing and Chakrabarti, 2009), and -\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 the scientific work paradigm (J\uf8rgensen, 1992), the last two combined with multiple case studies. Also, elements of action research (Oosthuizen, 2002) are used. The results show that the principles and introduction of LPD were experienced as positive by participating practitioners in the conducted case studies. It was furthermore shown that SBD can be introduced and applied in a workshop at team level within a time frame of one or two working days if the design problem at hand is not too complex. Another result is that SBD can be combined with and supported by established methods such as creative and systematic methods for synthesis, enhanced function-means modelling, axiomatic design, extended causal diagrammes, interactive evolutionary algorithms (IEA) and Pugh matrices for generation, analysis, evaluation and reduction of a solution space of design alternatives and variants of these. Both qualitative and quantitative requirements can be handled. The conclusions are that a transformation to LPD is facilitated by information about good examples and internal support by management. Also, the existence of a lean enthusiast in the organization and an appropriate implementation plan supports a transformation to LPD. A function to maintain the LPD system as well as influence of the lean principles are valuable guides on how to use LPD.\ua0 Also concluded is that a seamless, efficient process, applying set-based principles, for synthesis, evaluation, and reduction of a solution space of design alternatives can be created by combining enhanced function-means modelling, morphological matrices, axiomatic design, causal diagrammes and Pugh matrices. Such a compound of methods can be introduced and applied in a workshop at team level within a time frame of one to two days when solving well-known and not too complex design problems. The workshop should be facilitated by an expert on the methods used and initiated and surveyed by a team manager. Furthermore, a solution space of parameterised design variants, with criteria that are either qualitative or too complicated to be numerically defined, can be generated, evaluated and reduced in such a process. By using a defined set of functional and constraining criteria, and applying axiomatic design and IEA, a variant solution space can be generated and refined. A set-up of the IEA that does not overburden the user should be preferred
Integrated Circuit Design for High Data Rate Polymer Microwave Fiber Communication
The rapid development of semiconductor processes with a maximum frequency of oscillation well above 300 GHz enables new applications at frequencies above 100 GHz to be researched and developed. Such applications include wireless backhaul, wireless access, radar and radiometer sensors, wireless energy distribution and harvesting, etc.\ua0For several of these applications, a throughput in data rate well above 10 Gbps, even up to 100 Gbps, is required. Optical fiber communication is the leading option for high data rate and long-range wired communication. However, for shorter ranges like chip-to-chip or module-to-module (up to ten meters), millimeter-wave communication over a polymer microwave fiber (PMF) is an interesting alternative due to its potential low cost. Other advantages include flexibility, less sensitivity to temperature variations, and a more relaxed mechanical tolerance requirement. Similar to optical fiber, dispersion occurs on PMFs and will cause symbol interference. Different ways to deal with this effect are investigated, for example, pulse shaping and equalization of the signal.\ua0This work proposes and presents various circuit solutions enabling high data rate communication. Two technologies are used, 250 nm InP DHBT and 130 nm SiGe BiCMOS. An energy-efficient solution using an RF-DAC and power detector for pulse amplitude modulated links are evaluated, as well as an I/Q modulated solution. I/Q (de-)modulators require more complexity, but the increased spectral efficiency can also increase the data rate further.\ua0\ua0In summary, I explore the opportunities and challenges of short-range, ultra-high data rate, PMF bound communication, which is found to support 56 Gbps error-free (BER<10-12) data and 102 Gbps with a BER=2.1*10-3
Formation and characterization of FeLV iscoms.
Immunostimulating complexes (ISCOMs) have been prepared from feline leukaemia virus (FeLV) envelope proteins. The ISCOMs were characterized biochemically in SDS-polyacrylamide gel electrophoresis showing the presence of proteins of estimated molecular weights of 15,000, 27,000 and 70,000. Immunoblotting showed that both the transmembrane protein p15E and the external glycoprotein gp70 (making up the gp85 protein) were present in the ISCOM. Furthermore, a degradation product of gp70 with an estimated molecular weight of 32,000 was identified in the immunoblot. The FeLV ISCOM was shown by electron microscopy to have the characteristic cage-like structure of an ISCOM with a mean diameter of 37 nm. About 10% of the total amount of gp70 in the culture fluid was recovered in the ISCOMs. The largest loss was encountered during the sedimentation of the virus. In a preliminary immunization experiment in mice the FeLV ISCOMs elicited after a booster gave a clear-cut immune response against gp70
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