Life Cycle Models, Heterogeneity of Initial Assets,and Wealth Inequality

Life cycle general equilibrium models with heterogeneous agents have a very hard time reproducing the American wealth distribution. A common assumption made in this literature is that all young adults enter the economy with no initial assets. In this article, we relax this assumption – not supported by the data - and evaluate the ability of an otherwise standard life cycle model to account for the U.S. wealth inequality. The new feature of the model is that agents enter the economy with assets drawn from an initial distribution of assets, which is estimated using a non-parametric method applied to data from the Survey of Consumer Finances. We found that heterogeneity with respect to initial wealth is key for this class of models to replicate the data. According to our results, American inequality can be explained almost entirely by the fact that some individuals are lucky enough to be born into wealth, while others are born with few or no assets.

Risk-based decision support system for life cycle management of industrials plants

Dissertação para obtenção do Grau de Doutor em Engenharia Electrotécnica e de Computadores

Life-Cycle, Effort and Academic Inactivity

It has been observed that university professors sometimes become less research active in their later years. This paper models the decision to become inactive as a utility maximising problem under conditions of uncertainty and derives an age-dependent activity condition for the level of research productivity. The model implies that professors who are close to retirement age are more likely to become inactive when faced with setbacks in their research while those who continue research do not lower their activity levels. Using data from the University of Iceland, we find support for the model’s predictions. The model suggests that universities should induce their older faculty to remain research active by striving to make their research more productive and enjoyable, maintaining peer pressure, reducing job security and offering higher performance related pay.

Integrating human indoor air pollutant exposure within Life Cycle Impact Assessment.

Neglecting health effects from indoor pollutant emissions and exposure, as currently done in Life Cycle Assessment (LCA), may result in product or process optimizations at the expense of workers' or consumers' health. To close this gap, methods for considering indoor exposure to chemicals are needed to complement the methods for outdoor human exposure assessment already in use. This paper summarizes the work of an international expert group on the integration of human indoor and outdoor exposure in LCA, within the UNEP/ SETAC Life Cycle Initiative. A new methodological framework is proposed for a general procedure to include human-health effects from indoor exposure in LCA. Exposure models from occupational hygiene and household indoor air quality studies and practices are critically reviewed and recommendations are provided on the appropriateness of various model alternatives in the context of LCA. A single-compartment box model is recommended for use as a default in LCA, enabling one to screen occupational and household exposures consistent with the existing models to assess outdoor emission in a multimedia environment. An initial set of model parameter values was collected. The comparison between indoor and outdoor human exposure per unit of emission shows that for many pollutants, intake per unit of indoor emission may be several orders of magnitude higher than for outdoor emissions. It is concluded that indoor exposure should be routinely addressed within LCA.

Predictable Life-Cycle Shocks, Income Risk and Consumption Inequality

Was the increase in income inequality in the US due to permanent shocks or merely to an increase in the variance of transitory shocks? The implications for consumption and welfare depend crucially on the answer to this question. We use CEX repeated cross-section data on consumption and income to decompose idiosyncratic changes in income into predictable life-cycle changes, transitory and permanent shocks and estimate the contribution of each to total inequality. Our model fits the joint evolution of consumption and income inequality well and delivers two main results. First, we find that permanent changes in income explain all of the increase in inequality in the 1980s and 90s. Second, we reconcile this finding with the fact that consumption inequality did not increase much over this period. Our results support the view that many permanent changes in income are predictable for consumers, even if they look unpredictable to the econometrician, consistent with models of heterogeneous income profiles.

Radar analysis of the life cycle of mesoscale convective systems during the 10 June 2000 event

The 10 June 2000 event was the largest flash flood event that occurred in the Northeast of Spain in the late 20th century, both as regards its meteorological features and its considerable social impact. This paper focuses on analysis of the structures that produced the heavy rainfalls, especially from the point of view of meteorological radar. Due to the fact that this case is a good example of a Mediterranean flash flood event, a final objective of this paper is to undertake a description of the evolution of the rainfall structure that would be sufficiently clear to be understood at an interdisciplinary forum. Then, it could be useful not only to improve conceptual meteorological models, but also for application in downscaling models. The main precipitation structure was a Mesoscale Convective System (MCS) that crossed the region and that developed as a consequence of the merging of two previous squall lines. The paper analyses the main meteorological features that led to the development and triggering of the heavy rainfalls, with special emphasis on the features of this MCS, its life cycle and its dynamic features. To this end, 2-D and 3-D algorithms were applied to the imagery recorded over the complete life cycle of the structures, which lasted approximately 18 h. Mesoscale and synoptic information were also considered. Results show that it was an NS-MCS, quasi-stationary during its stage of maturity as a consequence of the formation of a convective train, the different displacement directions of the 2-D structures and the 3-D structures, including the propagation of new cells, and the slow movement of the convergence line associated with the Mediterranean mesoscale low.

Integrating life cycle costs and environmental impacts of composite rail car-bodies for a Korean train

Background, aim, and scope A coupled Life Cycle Costing and life cycle assessment has been performed for car-bodies of the Korean Tilting Train eXpress (TTX) project using European and Korean databases, with the objective of assessing environmental and cost performance to aid materials and process selection. More specifically, the potential of polymer composite car-body structures for the Korean Tilting Train eXpress (TTX) has been investigated. Materials and methods This assessment includes the cost of both carriage manufacturing and use phases, coupled with the life cycle environmental impacts of all stages from raw material production, through carriage manufacture and use, to end-of-life scenarios. Metallic carriages were compared with two composite options: hybrid steel-composite and full-composite carriages. The total planned production for this regional Korean train was 440 cars, with an annual production volume of 80 cars. Results and discussion The coupled analyses were used to generate plots of cost versus energy consumption and environmental impacts. The results show that the raw material and manufacturing phase costs are approximately half of the total life cycle costs, whilst their environmental impact is relatively insignificant (3-8%). The use phase of the car-body has the largest environmental impact for all scenarios, with near negligible contributions from the other phases. Since steel rail carriages weigh more (27-51%), the use phase cost is correspondingly higher, resulting in both the greatest environmental impact and the highest life cycle cost. Compared to the steel scenario, the hybrid composite variant has a lower life cycle cost (16%) and a lower environmental impact (26%). Though the full composite rail carriage may have the highest manufacturing cost, it results in the lowest total life cycle costs and lowest environmental impacts. Conclusions and recommendations This coupled cost and life cycle assessment showed that the full composite variant was the optimum solution. This case study showed that coupling of technical cost models with life cycle assessment offers an efficient route to accurately evaluate economic and environmental performance in a consistent way.

Applying the principles of life cycle assessment and costing in process modeling to examine profit-making capability

Static process simulation has traditionally been used to model complex processes for various purposes. However, the use of static processsimulators for the preparation of holistic examinations aiming at improving profit-making capability requires a lot of work because the production of results requires the assessment of the applicability of detailed data which may be irrelevant to the objective. The relevant data for the total assessment gets buried byirrelevant data. Furthermore, the models do not include an examination of the maintenance or risk management, and economic examination is often an extra property added to them which can be performed with a spreadsheet program. A process model applicable to holistic economic examinations has been developed in this work. The model is based on the life cycle profit philosophy developed by Hagberg and Henriksson in 1996. The construction of the model has utilized life cycle assessment and life cycle costing methodologies with a view to developing, above all, a model which would be applicable to the economic examinations of complete wholes and which would require the need for information focusing on aspects essential to the objectives. Life cycle assessment and costing differ from each other in terms of the modeling principles, but the features of bothmethodologies can be used in the development of economic process modeling. Methods applicable to the modeling of complex processes can be examined from the viewpoint of life cycle methodologies, because they involve the collection and management of large corpuses of information and the production of information for the needs of decision-makers as well. The results of the study shows that on the basis of the principles of life cycle modeling, a process model can be created which may be used to produce holistic efficiency examinations on the profit-making capability of the production line, with fewer resources thanwith traditional methods. The calculations of the model are based to the maximum extent on the information system of the factory, which means that the accuracyof the results can be improved by developing information systems so that they can provide the best information for this kind of examinations.

Integration of Economics into Life Cycle Assessment in the Finnish Pulp and Paper Industry

Taloudellisen laskennan yhdistäminen elinkaariarviointiin (LCA) on alkanut kiinnostaa eri teollisuuden aloja maailmanlaajuisesti viime aikoina. Useat LCA-tietokoneohjelmat sisältävät kustannuslaskentaominaisuuksia ja yksittäiset projektit ovat yhdistäneet ympäristö- ja talouslaskentamenetelmiä. Tässä projektissa tutkitaan näiden yhdistelmien soveltuvuutta suomalaiselle sellu- ja paperiteollisuudelle, sekä kustannuslaskentaominaisuuden lisäämistä KCL:n LCA-ohjelmaan, KCL-ECO 3.0:aan. Kaikki tutkimuksen aikana löytyneet menetelmät, jotka yhdistävät LCA:n ja taloudellista laskentaa, on esitelty tässä työssä. Monet näistä käyttävät elinkaarikustannusarviointia (LCCA). Periaatteessa elinkaari määritellään eri tavalla LCCA:ssa ja LCA:ssa, mikä luo haasteita näiden menetelmien yhdistämiselle. Sopiva elinkaari tulee määritellä laskennan tavoitteiden mukaisesti. Työssä esitellään suositusmenetelmä, joka lähtee suomalaisen sellu- ja paperiteollisuuden erikoispiirteistä. Perusvaatimuksena on yhteensopivuus tavanomaisesti paperin LCA:ssa käytetyn elinkaaren kanssa. Menetelmän yhdistäminen KCL-ECO 3.0:aan on käsitelty yksityiskohtaisesti.

The holistic military capability life cycle model

Abstract - This paper reviews existing military capability models and the capability life cycle. It proposes a holistic capability life-cycle model (HCLCM) that combines capability systems with related capability models. ISO 15288 standard is used as a framework to construct the HCLCM. The HCLCM also shows how capability models and systems relate to each other throughout the capability life cycle. The main contribution of this paper is conceptual in nature. The model complements the existing, but still evolving, understanding of the military capability life cycle in a holistic and systemic way. The model also increases understanding and facilitates communication among various military capability stakeholders.

Creating an open-books implementation framework for a maintenance-related value-based life-cycle model

This study is a qualitative action research by its nature with elements of personal design in the form of a tangible model implementation framework construction. Utilized empirical data has been gathered via two questionnaires in relation to the arranged four workshop events with twelve individual participants. Five of them represented maintenance customers, three maintenance service providers and four equipment providers respectively. Further, there are two main research objectives in proportion to the two complementary focusing areas of this thesis. Firstly, the value-based life-cycle model, which first version has already been developed prior to this thesis, requires updating in order to increase its real-life applicability as an inter-firm decision-making tool in industrial maintenance. This first research objective is fulfilled by improving appearance, intelligibility and usability of the above-mentioned model. In addition, certain new features are also added. The workshop participants from the collaborating companies were reasonably pleased with made changes, although further attention will be required in future on the model’s intelligibility in particular as main results, charts and values were all reckoned as slightly hard to understand. Moreover, upgraded model’s appearance and added new features satisfied them the most. Secondly and more importantly, the premises of the model’s possible inter-firm implementation process need to be considered. This second research objective is delivered in two consecutive steps. At first, a bipartite open-books supported implementation framework is created and its different characteristics discussed in theory. Afterwards, the prerequisites and the pitfalls of increasing inter-organizational information transparency are studied in empirical context. One of the main findings was that the organizations are not yet prepared for network-wide information disclosure as dyadic collaboration was favored instead. However, they would be willing to share information bilaterally at least. Another major result was that the present state of companies’ cost accounting systems will definitely need implementation-wise enhancing in future since accurate and sufficiently detailed maintenance data is not available. Further, it will also be crucial to create supporting and mutually agreed network infrastructure. There are hardly any collaborative models, methods or tools currently in usage. Lastly, the essential questions about mutual trust and predominant purchasing strategies are cooperation-wise important. If inter-organizational activities are expanded, a more relational approach should be favored in this regard. Mutual trust was also recognized as a significant cooperation factor, but it is hard to measure in reality.

Evaluating land-use related environmental impacts of biomass value chains for decision-support : Comparison and testing of methodologies proposed for environmental life cycle assessment

Life cycle assessment (LCA) is one of the most established quantitative tools for environmental impact assessment of products. To be able to provide support to environmentally-aware decision makers on environmental impacts of biomass value-chains, the scope of LCA methodology needs to be augmented to cover landuse related environmental impacts. This dissertation focuses on analysing and discussing potential impact assessment methods, conceptual models and environmental indicators that have been proposed to be implemented into the LCA framework for impacts of land use. The applicability of proposed indicators and impact assessment frameworks is tested from practitioners' perspective, especially focusing on forest biomass value chains. The impacts of land use on biodiversity, resource depletion, climate change and other ecosystem services is analysed and discussed and the interplay in between value choices in LCA modelling and the decision-making situations to be supported is critically discussed. It was found out that land use impact indicators are necessary in LCA in highlighting differences in impacts from distinct land use classes. However, many open questions remain on certainty of highlighting actual impacts of land use, especially regarding impacts of managed forest land use on biodiversity and ecosystem services such as water regulation and purification. The climate impact of energy use of boreal stemwood was found to be higher in the short term and lower in the long-term in comparison with fossil fuels that emit identical amount of CO2 in combustion, due to changes implied to forest C stocks. The climate impacts of energy use of boreal stemwood were found to be higher than the previous estimates suggest on forest residues and stumps. The product lifetime was found to have much higher influence on the climate impacts of woodbased value chains than the origin of stemwood either from thinnings or final fellings. Climate neutrality seems to be likely only in the case when almost all the carbon of harvested wood is stored in long-lived wooden products. In the current form, the land use impacts cannot be modelled with a high degree of certainty nor communicated with adequate level of clarity to decision makers. The academia needs to keep on improving the modelling framework, and more importantly, clearly communicate to decision-makers the limited certainty on whether land-use intensive activities can help in meeting the strict mitigation targets we are globally facing.

Supply base development for life-cycle business

Yritysten liiketoimintamallit ovat jatkuvan kehityksen kohteena. Viimeisinä vuosina valmistavien yhtiöiden kiinnostus huolehtia asiakkaistaan koko tuotteen elinkaaren aikana ja tarjota erilaisia palveluita asiakkailleen on kasvanut. Tämän palvelujen laajentumisen myötä myös vaateet yrityksen omaa toimittajakenttää kohtaan ovat muuttuneet. Yritykset eivät kykene tuottamaan kaikkia tuotteistamiaan palveluja itse, jolloin yrityksen toimittajakenttä ja sen kyvykkyydet tuottaa tarvittavia palveluita ovat avainasemassa yrityksen menestystekijänä. Tämän työn teoriaosuudessa on esitelty toimittajakentän hallinnan perusteorioita. Kirjallisuus osuuden lisäksi työssä on hyödynnetty toimintatutkimusta kohdeyrityksessä. Tässä diplomityössä on tutkittu mahdollisia keinoja kehittää organisaation omaa toimintaa ja sekä yrityksen toimittajakenttää niin, että se tukee liiketoimintamallin kehitystä koneenrakennusyrityksestä kohti elinkaariliiketoimintaa. Työssä esitetyt keinot voidaan ottaa käyttöön, joko yksitellen tai kokonaisuutena.

Item-level life-cycle model for maintenance network – from cost to additional value

The importance of industrial maintenance has been emphasized during the last decades; it is no longer a mere cost item, but one of the mainstays of business. Market conditions have worsened lately, investments in production assets have decreased, and at the same time competition has changed from taking place between companies to competition between networks. Companies have focused on their core functions and outsourced support services, like maintenance, above all to decrease costs. This new phenomenon has led to increasing formation of business networks. As a result, a growing need for new kinds of tools for managing these networks effectively has arisen. Maintenance costs are usually a notable part of the life-cycle costs of an item, and it is important to be able to plan the future maintenance operations for the strategic period of the company or for the whole life-cycle period of the item. This thesis introduces an itemlevel life-cycle model (LCM) for industrial maintenance networks. The term item is used as a common definition for a part, a component, a piece of equipment etc. The constructed LCM is a working tool for a maintenance network (consisting of customer companies that buy maintenance services and various supplier companies). Each network member is able to input their own cost and profit data related to the maintenance services of one item. As a result, the model calculates the net present values of maintenance costs and profits and presents them from the points of view of all the network members. The thesis indicates that previous LCMs for calculating maintenance costs have often been very case-specific, suitable only for the item in question, and they have also been constructed for the needs of a single company, without the network perspective. The developed LCM is a proper tool for the decision making of maintenance services in the network environment; it enables analysing the past and making scenarios for the future, and offers choices between alternative maintenance operations. The LCM is also suitable for small companies in building active networks to offer outsourcing services for large companies. The research introduces also a five-step constructing process for designing a life-cycle costing model in the network environment. This five-step designing process defines model components and structure throughout the iteration and exploitation of user feedback. The same method can be followed to develop other models. The thesis contributes to the literature of value and value elements of maintenance services. It examines the value of maintenance services from the perspective of different maintenance network members and presents established value element lists for the customer and the service provider. These value element lists enable making value visible in the maintenance operations of a networked business. The LCM added with value thinking promotes the notion of maintenance from a “cost maker” towards a “value creator”.

Vision 2020 - A whole life-cycle information management system for built environments

A whole life-cycle information management vision is proposed, the organizational requirements for the realization of the scenario is investigated. Preliminary interviews with construction professionals are reported. Discontinuities at information transfer throughout life-cycle of built environments are resulting from lack of coordination and multiple data collection/storage practices. A more coherent history of these activities can improve the work practices of various teams by augmenting decision making processes and creating organizational learning opportunities. Therefore, there is a need for unifying these fragmented bits of data to create a meaningful, semantically rich and standardized information repository for built environment. The proposed vision utilizes embedded technologies and distributed building information models. Two diverse construction project types (large one-off design, small repetitive design) are investigated for the applicability of the vision. A functional prototype software/hardware system for demonstrating the practical use of this vision is developed and discussed. Plans for case-studies for validating the proposed model at a large PFI hospital and housing association projects are discussed.