Biological production in the Indian Ocean upwelling zones - Part 1: refined estimation via the use of a variable compensation depth in ocean carbon models

Science.gov (United States)

Geethalekshmi Sreeush, Mohanan; Valsala, Vinu; Pentakota, Sreenivas; Venkata Siva Rama Prasad, Koneru; Murtugudde, Raghu

2018-04-01

Biological modelling approach adopted by the Ocean Carbon-Cycle Model Intercomparison Project (OCMIP-II) provided amazingly simple but surprisingly accurate rendition of the annual mean carbon cycle for the global ocean. Nonetheless, OCMIP models are known to have seasonal biases which are typically attributed to their bulk parameterisation of compensation depth. Utilising the criteria of surface Chl a-based attenuation of solar radiation and the minimum solar radiation required for production, we have proposed a new parameterisation for a spatially and temporally varying compensation depth which captures the seasonality in the production zone reasonably well. This new parameterisation is shown to improve the seasonality of CO2 fluxes, surface ocean pCO2, biological export and new production in the major upwelling zones of the Indian Ocean. The seasonally varying compensation depth enriches the nutrient concentration in the upper ocean yielding more faithful biological exports which in turn leads to accurate seasonality in the carbon cycle. The export production strengthens by ˜ 70 % over the western Arabian Sea during the monsoon period and achieves a good balance between export and new production in the model. This underscores the importance of having a seasonal balance in the model export and new productions for a better representation of the seasonality of the carbon cycle over upwelling regions. The study also implies that both the biological and solubility pumps play an important role in the Indian Ocean upwelling zones.

Biological and physical controls in the Southern Ocean on past millennial-scale atmospheric CO2 changes.

Science.gov (United States)

Gottschalk, Julia; Skinner, Luke C; Lippold, Jörg; Vogel, Hendrik; Frank, Norbert; Jaccard, Samuel L; Waelbroeck, Claire

2016-05-17

Millennial-scale climate changes during the last glacial period and deglaciation were accompanied by rapid changes in atmospheric CO2 that remain unexplained. While the role of the Southern Ocean as a 'control valve' on ocean-atmosphere CO2 exchange has been emphasized, the exact nature of this role, in particular the relative contributions of physical (for example, ocean dynamics and air-sea gas exchange) versus biological processes (for example, export productivity), remains poorly constrained. Here we combine reconstructions of bottom-water [O2], export production and (14)C ventilation ages in the sub-Antarctic Atlantic, and show that atmospheric CO2 pulses during the last glacial- and deglacial periods were consistently accompanied by decreases in the biological export of carbon and increases in deep-ocean ventilation via southern-sourced water masses. These findings demonstrate how the Southern Ocean's 'organic carbon pump' has exerted a tight control on atmospheric CO2, and thus global climate, specifically via a synergy of both physical and biological processes.

Autonomous observations of the ocean biological carbon pump

Energy Technology Data Exchange (ETDEWEB)

Bishop, James K.B.

2009-03-01

Prediction of the substantial biologically mediated carbon flows in a rapidly changing and acidifying ocean requires model simulations informed by observations of key carbon cycle processes on the appropriate space and time scales. From 2000 to 2004, the National Oceanographic Partnership Program (NOPP) supported the development of the first low-cost fully-autonomous ocean profiling Carbon Explorers that demonstrated that year-round real-time observations of particulate organic carbon (POC) concentration and sedimentation could be achieved in the world's ocean. NOPP also initiated the development of a sensor for particulate inorganic carbon (PIC) suitable for operational deployment across all oceanographic platforms. As a result, PIC profile characterization that once required shipboard sample collection and shipboard or shore based laboratory analysis, is now possible to full ocean depth in real time using a 0.2W sensor operating at 24 Hz. NOPP developments further spawned US DOE support to develop the Carbon Flux Explorer, a free-vehicle capable of following hourly variations of particulate inorganic and organic carbon sedimentation from near surface to kilometer depths for seasons to years and capable of relaying contemporaneous observations via satellite. We have demonstrated the feasibility of real time - low cost carbon observations which are of fundamental value to carbon prediction and when further developed, will lead to a fully enhanced global carbon observatory capable of real time assessment of the ocean carbon sink, a needed constraint for assessment of carbon management policies on a global scale.

Influence of diatom diversity on the ocean biological carbon pump

Science.gov (United States)

Tréguer, Paul; Bowler, Chris; Moriceau, Brivaela; Dutkiewicz, Stephanie; Gehlen, Marion; Aumont, Olivier; Bittner, Lucie; Dugdale, Richard; Finkel, Zoe; Iudicone, Daniele; Jahn, Oliver; Guidi, Lionel; Lasbleiz, Marine; Leblanc, Karine; Levy, Marina; Pondaven, Philippe

2018-01-01

Diatoms sustain the marine food web and contribute to the export of carbon from the surface ocean to depth. They account for about 40% of marine primary productivity and particulate carbon exported to depth as part of the biological pump. Diatoms have long been known to be abundant in turbulent, nutrient-rich waters, but observations and simulations indicate that they are dominant also in meso- and submesoscale structures such as fronts and filaments, and in the deep chlorophyll maximum. Diatoms vary widely in size, morphology and elemental composition, all of which control the quality, quantity and sinking speed of biogenic matter to depth. In particular, their silica shells provide ballast to marine snow and faecal pellets, and can help transport carbon to both the mesopelagic layer and deep ocean. Herein we show that the extent to which diatoms contribute to the export of carbon varies by diatom type, with carbon transfer modulated by the Si/C ratio of diatom cells, the thickness of the shells and their life strategies; for instance, the tendency to form aggregates or resting spores. Model simulations project a decline in the contribution of diatoms to primary production everywhere outside of the Southern Ocean. We argue that we need to understand changes in diatom diversity, life cycle and plankton interactions in a warmer and more acidic ocean in much more detail to fully assess any changes in their contribution to the biological pump.

AMS Observations over Coastal California from the Biological and Oceanic Atmospheric Study (BOAS)

Science.gov (United States)

Bates, K. H.; Coggon, M. M.; Hodas, N.; Negron, A.; Ortega, A. M.; Crosbie, E.; Sorooshian, A.; Nenes, A.; Flagan, R. C.; Seinfeld, J.

2015-12-01

In July 2015, fifteen research flights were conducted on a US Navy Twin Otter aircraft as part of the Biological and Oceanic Atmospheric Study (BOAS) campaign. The flights took place near the California coast at Monterey, to investigate the effects of sea surface temperature and algal blooms on oceanic particulate emissions, the diurnal mixing of urban pollution with other airmasses, and the impacts of biological aerosols on the California atmosphere. The aircraft's payload included an aerosol mass spectrometer (AMS), a differential mobility analyzer, a cloud condensation nuclei counter, a counterflow virtual impactor, a cloudwater collector, and two instruments designed to detect biological aerosols - a wideband integrated biological spectrometer and a SpinCon II - as well as a number of meteorology and aerosol probes, two condensation particle counters, and instruments to measure gas-phase CO, CO2, O3, and NOx. Here, we describe in depth the objectives and outcomes of BOAS and report preliminary results, primarily from the AMS. We detail the spatial characteristics and meteorological variability of speciated aerosol components over a strong and persistent bloom of Pseudo-Nitzschia, the harmful algae that cause 'red tide', and report newly identified AMS markers for biological particles. Finally, we compare these results with data collected during BOAS over urban, forested, and agricultural environments, and describe the mixing observed between oceanic and terrestrial airmasses.

The Impact of Transaction Costs on Rebalancing an Investment Portfolio in Portfolio Optimization

OpenAIRE

B. Marasović; S. Pivac; S. V. Vukasović

2015-01-01

Constructing a portfolio of investments is one of the most significant financial decisions facing individuals and institutions. In accordance with the modern portfolio theory maximization of return at minimal risk should be the investment goal of any successful investor. In addition, the costs incurred when setting up a new portfolio or rebalancing an existing portfolio must be included in any realistic analysis. In this paper rebalancing an investment portfolio in the pr...

Application of Markowitz Portfolio Theory by Building Optimal Portfolio on the US Stock Market

OpenAIRE

Širůček, Martin; Křen, Lukáš

2015-01-01

ŠIRŮČEK MARTIN, KŘEN LUKÁŠ. 2015. Application of Markowitz Portfolio Theory by Building Optimal Portfolio on the US Stock Market. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 63(4): 1375–1386. This paper is focused on building investment portfolios by using the Markowitz Portfolio Theory (MPT). Derivation based on the Capital Asset Pricing Model (CAPM) is used to calculate the weights of individual securities in portfolios. The calculated portfolios include a po...

Comparison of Portfolio Selection and Performance: Shari’ah-Compliant and Socially Responsible Investment Portfolios

Directory of Open Access Journals (Sweden)

Mehmet Asutay

2015-04-01

Full Text Available This study examines the effect of Islamic screening criteria on Shari’ah-compliant portfolio selection and performance compared to Socially Responsible Investment (SRI portfolio. Each portfolio constructed from 15 stocks based on FTSE 100 using data from year 1997. Mean-variance portfolio optimization is employed with some financial ratios added as constraints for the Shari’ah portfolio. Annual expected return of each portfolio from 2008 to 2013 is used to calculate Sharpe’s ratio, Treynor ratio and Jensen’s alpha as the performance measurement tools. Macroeconomic variables are assessed using ordinary least square to examine whether they influence the portfolios’ expected returns or not. The result finds that Shari’ah portfolio has a better performance than SRI from year 2008 to 2010 shown by higher value of the measurement tools. However, from 2011 to 2013, SRI portfolio has better performance than Shari’ah portfolio. 

Leptokurtic portfolio theory

Science.gov (United States)

Kitt, R.; Kalda, J.

2006-03-01

The question of optimal portfolio is addressed. The conventional Markowitz portfolio optimisation is discussed and the shortcomings due to non-Gaussian security returns are outlined. A method is proposed to minimise the likelihood of extreme non-Gaussian drawdowns of the portfolio value. The theory is called Leptokurtic, because it minimises the effects from “fat tails” of returns. The leptokurtic portfolio theory provides an optimal portfolio for investors, who define their risk-aversion as unwillingness to experience sharp drawdowns in asset prices. Two types of risks in asset returns are defined: a fluctuation risk, that has Gaussian distribution, and a drawdown risk, that deals with distribution tails. These risks are quantitatively measured by defining the “noise kernel” — an ellipsoidal cloud of points in the space of asset returns. The size of the ellipse is controlled with the threshold parameter: the larger the threshold parameter, the larger return are accepted for investors as normal fluctuations. The return vectors falling into the kernel are used for calculation of fluctuation risk. Analogously, the data points falling outside the kernel are used for the calculation of drawdown risks. As a result the portfolio optimisation problem becomes three-dimensional: in addition to the return, there are two types of risks involved. Optimal portfolio for drawdown-averse investors is the portfolio minimising variance outside the noise kernel. The theory has been tested with MSCI North America, Europe and Pacific total return stock indices.

Concurrent credit portfolio losses.

Science.gov (United States)

Sicking, Joachim; Guhr, Thomas; Schäfer, Rudi

2018-01-01

We consider the problem of concurrent portfolio losses in two non-overlapping credit portfolios. In order to explore the full statistical dependence structure of such portfolio losses, we estimate their empirical pairwise copulas. Instead of a Gaussian dependence, we typically find a strong asymmetry in the copulas. Concurrent large portfolio losses are much more likely than small ones. Studying the dependences of these losses as a function of portfolio size, we moreover reveal that not only large portfolios of thousands of contracts, but also medium-sized and small ones with only a few dozens of contracts exhibit notable portfolio loss correlations. Anticipated idiosyncratic effects turn out to be negligible. These are troublesome insights not only for investors in structured fixed-income products, but particularly for the stability of the financial sector. JEL codes: C32, F34, G21, G32, H81.

An Ocean Biology-induced Negative Feedback on ENSO in the Tropical Pacific Climate System

Science.gov (United States)

Zhang, R. H.

2016-02-01

Biological conditions in the tropical Pacific Ocean (e.g., phytoplankton biomass) are strongly regulated by physical changes associated with the El Niño-Southern Oscillation (ENSO). The existence and variation of phytoplankton biomass, in turn, act to modulate the vertical penetration of the incoming sunlight in the upper ocean, presenting an ocean biology-induced heating (OBH) effect on the climate system. Previously, a penetration depth of solar radiation in the upper ocean (Hp) is defined to describe the related bio-climate connections. Parameterized in terms of its relationship with the sea surface temperature (SST) in the tropical Pacific, an empirical model for interannual Hp variability has been derived from remotely sensed ocean color data, which is incorporated into a hybrid coupled model (HCM) to represent OBH effects. In this paper, various HCM experiments are performed to demonstrate the bio-feedback onto ENSO, including a climatological Hp run (in which Hp is prescribed as seasonally varying only), interannual Hp runs (with different intensities of interannually varying OBH effects), and a run in which the sign of the OBH effect is artificially reversed. Significant modulating impacts on interannual variability are found in the HCM, characterized by a negative feedback between ocean biology and the climate system in the tropical Pacific: the stronger the OBH feedback, the weaker the interannual variability. Processes involved in the feedback are analyzed; it is illustrated that the SST is modulated indirectly by ocean dynamical processes induced by OBH. The significance and implication of the OBH effects are discussed for their roles in ENSO variability and model biases in the tropical Pacific.

78 FR 21045 - Confirmation, Portfolio Reconciliation, Portfolio Compression, and Swap Trading Relationship...

Science.gov (United States)

2013-04-09

... COMMODITY FUTURES TRADING COMMISSION 17 CFR Part 23 RIN 3038-AC96 Confirmation, Portfolio Reconciliation, Portfolio Compression, and Swap Trading Relationship Documentation Requirements for Swap Dealers... CFTC published final rules setting forth requirements for swap confirmation, portfolio reconciliation...

Measuring Treasury Bond Portfolio Risk and Portfolio Optimization with a Non-Gaussian Multivariate Model

Science.gov (United States)

Dong, Yijun

The research about measuring the risk of a bond portfolio and the portfolio optimization was relatively rare previously, because the risk factors of bond portfolios are not very volatile. However, this condition has changed recently. The 2008 financial crisis brought high volatility to the risk factors and the related bond securities, even if the highly rated U.S. treasury bonds. Moreover, the risk factors of bond portfolios show properties of fat-tailness and asymmetry like risk factors of equity portfolios. Therefore, we need to use advanced techniques to measure and manage risk of bond portfolios. In our paper, we first apply autoregressive moving average generalized autoregressive conditional heteroscedasticity (ARMA-GARCH) model with multivariate normal tempered stable (MNTS) distribution innovations to predict risk factors of U.S. treasury bonds and statistically demonstrate that MNTS distribution has the ability to capture the properties of risk factors based on the goodness-of-fit tests. Then based on empirical evidence, we find that the VaR and AVaR estimated by assuming normal tempered stable distribution are more realistic and reliable than those estimated by assuming normal distribution, especially for the financial crisis period. Finally, we use the mean-risk portfolio optimization to minimize portfolios' potential risks. The empirical study indicates that the optimized bond portfolios have better risk-adjusted performances than the benchmark portfolios for some periods. Moreover, the optimized bond portfolios obtained by assuming normal tempered stable distribution have improved performances in comparison to the optimized bond portfolios obtained by assuming normal distribution.

Shifting the Perspective: Artists in the Ocean

Science.gov (United States)

Van Dover, C. L.

2014-12-01

The deep ocean is to most of us a place unknown. Few of us experience the sea far from shore, fewer still dive to the seafloor at great depths. When scientists report on the outcome of deep-ocean exploration, their technical prose captures facts and insights, but fails to capture the emotional power of place and process. Through batik, watercolor illustrations, music, digital art, cartoon, and experimental video, six artists have created a portfolio of work that communicates the human experience of the deep ocean.

Parametric Portfolio Selection: Evaluating and Comparing to Markowitz Portfolios

Directory of Open Access Journals (Sweden)

Marcelo C. Medeiros

2014-10-01

Full Text Available In this paper we exploit the parametric portfolio optimization in the Brazilian market. Our data consists of monthly returns of 306 Brazilian stocks in the period between 2001 and 2013. We tested the model both in and out of sample and compared the results with the value and equal weighted portfolios and with a Markowitz based portfolio. We performed statistical inference in the parametric optimization using bootstrap techniques in order to build the parameters empirical distributions. Our results showed that the parametric optimization is a very efficient technique out of sample. It consistently showed superior results when compared with the VW, EW and Markowitz portfolios even when transaction costs were included. Finally, we consider the parametric approach to be very flexible to the inclusion of constraints in weights, transaction costs and listing and delisting of stocks.

Comprehensive Education Portfolio with a Career Focus

Science.gov (United States)

Kruger, Evonne J.; Holtzman, Diane M.; Dagavarian, Debra A.

2013-01-01

There are many types of student portfolios used within academia: the prior learning portfolio, credentialing portfolio, developmental portfolio, capstone portfolio, individual course portfolio, and the comprehensive education portfolio. The comprehensive education portfolio (CEP), as used by the authors, is a student portfolio, developed over…

Academic portfolio in the digital era: organizing and maintaining a portfolio using reference managers.

Science.gov (United States)

Bhargava, Puneet; Patel, Vatsal B; Iyer, Ramesh S; Moshiri, Mariam; Robinson, Tracy J; Lall, Chandana; Heller, Matthew T

2015-02-01

The academic portfolio has become an integral part of the promotions process. Creating and maintaining an academic portfolio in paper-based or web-based formats can be a cumbersome and time-consuming task. In this article, we describe an alternative way to efficiently organize an academic portfolio using a reference manager software, and discuss some of the afforded advantages. The reference manager software Papers (Mekentosj, Amsterdam, The Netherlands) was used to create an academic portfolio. The article outlines the key steps in creating and maintaining a digital academic portfolio. Using reference manager software (Papers), we created an academic portfolio that allows the user to digitally organize clinical, teaching, and research accomplishments in an indexed library enabling efficient updating, rapid retrieval, and easy sharing. To our knowledge, this is the first digital portfolio of its kind.

IPCC workshop on impacts of ocean acidification on marine biology and ecosystems. Workshop report

Energy Technology Data Exchange (ETDEWEB)

Field, C.B.; Barros, V.; Stocker, T.F.; Dahe, Q.; Mach, K.J.; Plattner, G.-K.; Mastrandrea, M.D.; Tignor, M.; Ebi, K.L.

2011-09-15

Understanding the effects of increasing atmospheric CO{sub 2} concentrations on ocean chemistry, commonly termed ocean acidification, as well as associated impacts on marine biology and ecosystems, is an important component of scientific knowledge about global change. The Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) will include comprehensive coverage of ocean acidification and its impacts, including potential feedbacks to the climate system. To support ongoing AR5 assessment efforts, Working Group II and Working Group I (WGII and WGI) of the IPCC held a joint Workshop on Impacts of Ocean Acidification on Marine Biology and Ecosystems in Okinawa, Japan, from 17 to 19 January 2011. The workshop convened experts from the scientific community, including WGII and WGI AR5 authors and review editors, to synthesise scientific understanding of changes in ocean chemistry due to increased CO{sub 2} and of impacts of this changing chemistry on marine organisms, ecosystems, and ecosystem services. This workshop report summarises the scientific content and perspectives presented and discussed during the workshop. It provides syntheses of these perspectives for the workshop's core topics: (i) the changing chemistry of the oceans, (ii) impacts of ocean acidification for individual organisms, and (iii) scaling up responses from individual organisms to ecosystems. It also presents summaries of workshop discussions of key cross-cutting themes, ranging from detection and attribution of ocean acidification and its impacts to understanding ocean acidification in the context of other stressors on marine systems. Additionally, the workshop report includes extended abstracts for keynote and poster presentations at the workshop. (Author)

Switching portfolios.

Science.gov (United States)

Singer, Y

1997-08-01

A constant rebalanced portfolio is an asset allocation algorithm which keeps the same distribution of wealth among a set of assets along a period of time. Recently, there has been work on on-line portfolio selection algorithms which are competitive with the best constant rebalanced portfolio determined in hindsight (Cover, 1991; Helmbold et al., 1996; Cover and Ordentlich, 1996). By their nature, these algorithms employ the assumption that high returns can be achieved using a fixed asset allocation strategy. However, stock markets are far from being stationary and in many cases the wealth achieved by a constant rebalanced portfolio is much smaller than the wealth achieved by an ad hoc investment strategy that adapts to changes in the market. In this paper we present an efficient portfolio selection algorithm that is able to track a changing market. We also describe a simple extension of the algorithm for the case of a general transaction cost, including the transactions cost models recently investigated in (Blum and Kalai, 1997). We provide a simple analysis of the competitiveness of the algorithm and check its performance on real stock data from the New York Stock Exchange accumulated during a 22-year period. On this data, our algorithm outperforms all the algorithms referenced above, with and without transaction costs.

Portfolio langagier en francais (Language Portfolios in French).

Science.gov (United States)

Laplante, Bernard; Christiansen, Helen

2001-01-01

Suggests that first-year college students learning French should create a language portfolio that contains documents that illustrate what they have learned in French, along with a brief statement of what linguistic skill the document demonstrates. The goal of the portfolio is to make students more aware of their own learning, their strengths, and…

Do portfolios have a future?

Science.gov (United States)

Driessen, Erik

2017-03-01

While portfolios have seen an unprecedented surge in popularity, they have also become the subject of controversy: learners often perceive little gain from writing reflections as part of their portfolios; scholars question the ethics of such obligatory reflection; and students, residents, teachers and scholars alike condemn the bureaucracy surrounding portfolio implementation in competency-based education. It could be argued that mass adoption without careful attention to purpose and format may well jeopardize portfolios' viability in health sciences education. This paper explores this proposition by addressing the following three main questions: (1) Why do portfolios meet with such resistance from students and teachers, while educators love them?; (2) Is it ethical to require students to reflect and then grade their reflections?; (3) Does competency-based education empower or hamper the learner during workplace-based learning? Twenty-five years of portfolio reveal a clear story: without mentoring, portfolios have no future and are nothing short of bureaucratic hurdles in our competency-based education programs. Moreover, comprehensive portfolios, which are integrated into the curriculum and much more diverse in content than reflective portfolios, can serve as meaningful patient charts, providing doctor and patient with useful information to discuss well-being and treatment. In this sense, portfolios are also learner charts that comprehensively document progress in a learning trajectory which is lubricated by meaningful dialogue between learner and mentor in a trusting relationship to foster learning. If we are able to make such comprehensive and meaningful use of portfolios, then, yes, portfolios do have a bright future in medical education.

Teacher Portfolios.

Science.gov (United States)

Wolfe-Quintero, Kate; Brown, James Dean

1998-01-01

A portfolio of achievements, experiences, and reflections can help English-as-a-Second-Language teachers attain professional development goals and offer administrators greater insight for making informed hiring and job-performance decisions. This paper focuses on what teacher portfolios are, what their contents should be, and what their uses are…

Decentralized portfolio management

OpenAIRE

Coutinho, Paulo; Tabak, Benjamin Miranda

2003-01-01

We use a mean-variance model to analyze the problem of decentralized portfolio management. We find the solution for the optimal portfolio allocation for a head trader operating in n different markets, which is called the optimal centralized portfolio. However, as there are many traders specialized in different markets, the solution to the problem of optimal decentralized allocation should be different from the centralized case. In this paper we derive conditions for the solutions to be equiva...

Sparse and stable Markowitz portfolios.

Science.gov (United States)

Brodie, Joshua; Daubechies, Ingrid; De Mol, Christine; Giannone, Domenico; Loris, Ignace

2009-07-28

We consider the problem of portfolio selection within the classical Markowitz mean-variance framework, reformulated as a constrained least-squares regression problem. We propose to add to the objective function a penalty proportional to the sum of the absolute values of the portfolio weights. This penalty regularizes (stabilizes) the optimization problem, encourages sparse portfolios (i.e., portfolios with only few active positions), and allows accounting for transaction costs. Our approach recovers as special cases the no-short-positions portfolios, but does allow for short positions in limited number. We implement this methodology on two benchmark data sets constructed by Fama and French. Using only a modest amount of training data, we construct portfolios whose out-of-sample performance, as measured by Sharpe ratio, is consistently and significantly better than that of the naïve evenly weighted portfolio.

Dynamic Portfolio Strategy Using Clustering Approach.

Science.gov (United States)

Ren, Fei; Lu, Ya-Nan; Li, Sai-Ping; Jiang, Xiong-Fei; Zhong, Li-Xin; Qiu, Tian

2017-01-01

The problem of portfolio optimization is one of the most important issues in asset management. We here propose a new dynamic portfolio strategy based on the time-varying structures of MST networks in Chinese stock markets, where the market condition is further considered when using the optimal portfolios for investment. A portfolio strategy comprises two stages: First, select the portfolios by choosing central and peripheral stocks in the selection horizon using five topological parameters, namely degree, betweenness centrality, distance on degree criterion, distance on correlation criterion and distance on distance criterion. Second, use the portfolios for investment in the investment horizon. The optimal portfolio is chosen by comparing central and peripheral portfolios under different combinations of market conditions in the selection and investment horizons. Market conditions in our paper are identified by the ratios of the number of trading days with rising index to the total number of trading days, or the sum of the amplitudes of the trading days with rising index to the sum of the amplitudes of the total trading days. We find that central portfolios outperform peripheral portfolios when the market is under a drawup condition, or when the market is stable or drawup in the selection horizon and is under a stable condition in the investment horizon. We also find that peripheral portfolios gain more than central portfolios when the market is stable in the selection horizon and is drawdown in the investment horizon. Empirical tests are carried out based on the optimal portfolio strategy. Among all possible optimal portfolio strategies based on different parameters to select portfolios and different criteria to identify market conditions, 65% of our optimal portfolio strategies outperform the random strategy for the Shanghai A-Share market while the proportion is 70% for the Shenzhen A-Share market.

Dynamic Portfolio Strategy Using Clustering Approach.

Directory of Open Access Journals (Sweden)

Fei Ren

Full Text Available The problem of portfolio optimization is one of the most important issues in asset management. We here propose a new dynamic portfolio strategy based on the time-varying structures of MST networks in Chinese stock markets, where the market condition is further considered when using the optimal portfolios for investment. A portfolio strategy comprises two stages: First, select the portfolios by choosing central and peripheral stocks in the selection horizon using five topological parameters, namely degree, betweenness centrality, distance on degree criterion, distance on correlation criterion and distance on distance criterion. Second, use the portfolios for investment in the investment horizon. The optimal portfolio is chosen by comparing central and peripheral portfolios under different combinations of market conditions in the selection and investment horizons. Market conditions in our paper are identified by the ratios of the number of trading days with rising index to the total number of trading days, or the sum of the amplitudes of the trading days with rising index to the sum of the amplitudes of the total trading days. We find that central portfolios outperform peripheral portfolios when the market is under a drawup condition, or when the market is stable or drawup in the selection horizon and is under a stable condition in the investment horizon. We also find that peripheral portfolios gain more than central portfolios when the market is stable in the selection horizon and is drawdown in the investment horizon. Empirical tests are carried out based on the optimal portfolio strategy. Among all possible optimal portfolio strategies based on different parameters to select portfolios and different criteria to identify market conditions, 65% of our optimal portfolio strategies outperform the random strategy for the Shanghai A-Share market while the proportion is 70% for the Shenzhen A-Share market.

The standard for portfolio management

CERN Document Server

2017-01-01

The Standard for Portfolio Management – Fourth Edition has been updated to best reflect the current state of portfolio management. It describe the principles that drive accepted good portfolio management practices in today’s organizations. It also expands the description of portfolio management to reflect its relation to organizational project management and the organization.

Portfolios Dominating Indices: Optimization with Second-Order Stochastic Dominance Constraints vs. Minimum and Mean Variance Portfolios

Directory of Open Access Journals (Sweden)

Neslihan Fidan Keçeci

2016-10-01

Full Text Available The paper compares portfolio optimization with the Second-Order Stochastic Dominance (SSD constraints with mean-variance and minimum variance portfolio optimization. As a distribution-free decision rule, stochastic dominance takes into account the entire distribution of return rather than some specific characteristic, such as variance. The paper is focused on practical applications of the portfolio optimization and uses the Portfolio Safeguard (PSG package, which has precoded modules for optimization with SSD constraints, mean-variance and minimum variance portfolio optimization. We have done in-sample and out-of-sample simulations for portfolios of stocks from the Dow Jones, S&P 100 and DAX indices. The considered portfolios’ SSD dominate the Dow Jones, S&P 100 and DAX indices. Simulation demonstrated a superior performance of portfolios with SD constraints, versus mean-variance and minimum variance portfolios.

Making United States Integrated Ocean Observing System (U.S. IOOS) inclusive of marine biological resources

Science.gov (United States)

Moustahfid, H.; Potemra, J.; Goldstein, P.; Mendelssohn, R.; Desrochers, A.

2011-01-01

An important Data Management and Communication (DMAC) goal is to enable a multi-disciplinary view of the ocean environment by facilitating discovery and integration of data from various sources, projects and scientific domains. United States Integrated Ocean Observing System (U.S. IOOS) DMAC functional requirements are based upon guidelines for standardized data access services, data formats, metadata, controlled vocabularies, and other conventions. So far, the data integration effort has focused on geophysical U.S. IOOS core variables such as temperature, salinity, ocean currents, etc. The IOOS Biological Observations Project is addressing the DMAC requirements that pertain to biological observations standards and interoperability applicable to U.S. IOOS and to various observing systems. Biological observations are highly heterogeneous and the variety of formats, logical structures, and sampling methods create significant challenges. Here we describe an informatics framework for biological observing data (e.g. species presence/absence and abundance data) that will expand information content and reconcile standards for the representation and integration of these biological observations for users to maximize the value of these observing data. We further propose that the approach described can be applied to other datasets generated in scientific observing surveys and will provide a vehicle for wider dissemination of biological observing data. We propose to employ data definition conventions that are well understood in U.S. IOOS and to combine these with ratified terminologies, policies and guidelines. ?? 2011 MTS.

Post-modern portfolio theory supports diversification in an investment portfolio to measure investment's performance

OpenAIRE

Rasiah, Devinaga

2012-01-01

This study looks at the Post-Modern Portfolio Theory that maintains greater diversification in an investment portfolio by using the alpha and the beta coefficient to measure investment performance. Post-Modern Portfolio Theory appreciates that investment risk should be tied to each investor's goals and the outcome of this goal did not symbolize economic of the financial risk. Post-Modern Portfolio Theory's downside measure generated a noticeable distinction between downside and upside volatil...

Utility portfolio diversification

International Nuclear Information System (INIS)

Griffes, P.H.

1990-01-01

This paper discusses portfolio analysis as a method to evaluate utility supply decisions. Specifically a utility is assumed to increase the value of its portfolio of assets whenever it invests in a new supply technology. This increase in value occurs because the new asset either enhances the return or diversifies the risks of the firm's portfolio of assets. This evaluation method is applied to two supply innovations in the electric utility industry: jointly-owned generating plants and supply contracts with independent power producers (IPPs)

Teaching Portfolio

DEFF Research Database (Denmark)

Pedersen, Christian Fischer

The present teaching portfolio has been submitted for evaluation in partial fulfillment of the requirements of the teacher training programme for Assistant Professors at Department of Engineering, Aarhus University, Denmark.......The present teaching portfolio has been submitted for evaluation in partial fulfillment of the requirements of the teacher training programme for Assistant Professors at Department of Engineering, Aarhus University, Denmark....

Higher order thinking skills: using e-portfolio in project-based learning

Science.gov (United States)

Lukitasari, M.; Handhika, J.; Murtafiah, W.

2018-03-01

The purpose of this research is to describe students' higher-order thinking skills through project-based learning using e-portfolio. The method used in this research is descriptive qualitative method. The research instruments used were test, unstructured interview, and documentation. Research subjects were students of mathematics, physics and biology education department who take the Basics Physics course. The result shows that through project-based learning using e-portfolio the students’ ability to: analyze (medium category, N-Gain 0.67), evaluate (medium category, N-Gain 0.51), and create (medium Category, N-Gain 0.44) are improved.

Biological invasions on oceanic islands: Implications for island ecosystems and avifauna

Science.gov (United States)

Dean E. Pearson

2009-01-01

Biological invasions present a global threat to biodiversity, but oceanic islands are the systems hardest hit by invasions. Islands are generally depauperate in species richness, trophic complexity, and functional diversity relative to comparable mainland ecosystems. This situation results in low biotic resistance to invasion and many empty niches for invaders to...

Portfolio optimization with mean-variance model

Science.gov (United States)

Hoe, Lam Weng; Siew, Lam Weng

2016-06-01

Investors wish to achieve the target rate of return at the minimum level of risk in their investment. Portfolio optimization is an investment strategy that can be used to minimize the portfolio risk and can achieve the target rate of return. The mean-variance model has been proposed in portfolio optimization. The mean-variance model is an optimization model that aims to minimize the portfolio risk which is the portfolio variance. The objective of this study is to construct the optimal portfolio using the mean-variance model. The data of this study consists of weekly returns of 20 component stocks of FTSE Bursa Malaysia Kuala Lumpur Composite Index (FBMKLCI). The results of this study show that the portfolio composition of the stocks is different. Moreover, investors can get the return at minimum level of risk with the constructed optimal mean-variance portfolio.

Households' portfolio choices

NARCIS (Netherlands)

Hochgürtel, S.

1998-01-01

This thesis presents four topics on households' portfolio choices. Empirically, households do not hold well-diversified wealth portfolios. In particular, they refrain from putting their savings into risky assets. We explore several ways that might help explaining this observation. Using Dutch

Biological response to climate change in the Arctic Ocean: The view from the past

Science.gov (United States)

Cronin, Thomas M.; Cronin, Matthew A.

2017-01-01

The Arctic Ocean is undergoing rapid climatic changes including higher ocean temperatures, reduced sea ice, glacier and Greenland Ice Sheet melting, greater marine productivity, and altered carbon cycling. Until recently, the relationship between climate and Arctic biological systems was poorly known, but this has changed substantially as advances in paleoclimatology, micropaleontology, vertebrate paleontology, and molecular genetics show that Arctic ecosystem history reflects global and regional climatic changes over all timescales and climate states (103–107 years). Arctic climatic extremes include 25°C hyperthermal periods during the Paleocene-Eocene (56–46 million years ago, Ma), Quaternary glacial periods when thick ice shelves and sea ice cover rendered the Arctic Ocean nearly uninhabitable, seasonally sea-ice-free interglacials and abrupt climate reversals. Climate-driven biological impacts included large changes in species diversity, primary productivity, species’ geographic range shifts into and out of the Arctic, community restructuring, and possible hybridization, but evidence is not sufficient to determine whether or when major episodes of extinction occurred.

Evaluation of an established learning portfolio.

Science.gov (United States)

Vance, Gillian; Williamson, Alyson; Frearson, Richard; O'Connor, Nicole; Davison, John; Steele, Craig; Burford, Bryan

2013-02-01

The trainee-held learning portfolio is integral to the foundation programme in the UK. In the Northern Deanery, portfolio assessment is standardised through the Annual Review of Competence Progression (ARCP) process. In this study we aimed to establish how current trainees evaluate portfolio-based learning and ARCP, and how these attitudes may have changed since the foundation programme was first introduced. Deanery-wide trainee attitudes were surveyed by an electronic questionnaire in 2009 and compared with perceptions recorded during the pilot phase (2004-2005).  Many trainees continue to view the e-portfolio negatively. Indeed, significantly fewer trainees in 2009 thought that the e-portfolio was a 'good idea' or a 'worthwhile investment of time' than in 2005. Trainees remain unconvinced about the educational value of the e-portfolio: fewer trainees in 2009 regarded it as a tool that might help focus on training or recognise individual strengths and weaknesses. Issues around unnecessary bureaucracy persist. Current trainees tend to understand how to use the e-portfolio, but many did not know how much, or what evidence to collect. Few supervisors were reported to provide useful guidance on the portfolio. ARCP encouraged portfolio completion but did not give meaningful feedback to drive future learning.   Continued support is needed for both trainees and supervisors in portfolio-building skills and in using the e-portfolio as an educational tool. Trainee-tailored feedback is needed to ensure that portfolio-based assessment promotes lifelong, self-directed and reflective learners. © Blackwell Publishing Ltd 2013.

Making sense with ePortfolios

DEFF Research Database (Denmark)

Poulsen, Bo Klindt; Dimsits, Miriam

2017-01-01

of the statements from the students concerning their understanding of ePortfolio processes are fundamentally questions of how to make sense of the ePortfolio tool, both in their professional and personal lives. This calls for a didactical stance with the teachers who use ePortfolios, based on empowerment through......This article discusses the question of making sense out of working with ePortfolio in adult education. The article presents the results of a small-scale survey among adults in continuing education who have worked with ePortfolio as the central didactic principle. It is argued that many...... meaning-making, in order for ePortfolios to make sense. It is suggested that two relevant didactic perspectives for making sense of the world can be found in theories of biographicity and metaphor work. Moreover, a strong didactic stance that supports sense-making must be based on a strong teacher role...

Annual Report: EPAct Complementary Program's Ultra-Deepwater R&D Portfolio and Unconventional Resources R&D Portfolio (30 September 2012)

Energy Technology Data Exchange (ETDEWEB)

none,; Rose, Kelly [NETL; Hakala, Alexandra [NETL; Guthrie, George [NETL

2012-09-30

objective of this body of work is to build the scientific understanding and assessment tools necessary to develop the confidence that key domestic oil and gas resources can be produced safely and in an environmentally sustainable way. For the Deepwater and Ultra-Deepwater Portfolio, the general objective is to develop a scientific base for predicting and quantifying potential risks associated with exploration and production in extreme offshore environments. This includes: (1) using experimental studies to improve understanding of key parameters (e.g., properties and behavior of materials) tied to loss-of-control events in deepwater settings, (2) compiling data on spatial variability for key properties used to characterize and simulate the natural and engineered components involved in extreme offshore settings, and (3) utilizing findings from (1) and (2) in conjunction with integrated assessment models to model worst-case scenarios, as well as assessments of most likely scenarios relative to potential risks associated with flow assurance and loss of control. This portfolio and approach is responsive to key Federal-scale initiatives including the Ocean Energy Safety Advisory Committee (OESC). In particular, the findings and recommendations of the OESC's Spill Prevention Subcommittee are addressed by aspects of the Complementary Program research. The Deepwater and Ultra-Deepwater Portfolio is also aligned with some of the goals of the United States- Department of the Interior (US-DOI) led Alaska Interagency Working Group (AIWG) which brings together state, federal, and tribal government personnel in relation to energy-related issues and needs in the Alaskan Arctic. For the Unconventional Fossil Resources Portfolio, the general objective is to develop a sufficient scientific base for predicting and quantifying potential risks associated with the oil/gas resources in shale reservoirs that require hydraulic fracturing and/or other engineering measures to produce. The major

The biological carbon pump in the ocean: Reviewing model representations and its feedbacks on climate perturbations.

Science.gov (United States)

Hülse, Dominik; Arndt, Sandra; Ridgwell, Andy; Wilson, Jamie

2016-04-01

The ocean-sediment system, as the biggest carbon reservoir in the Earth's carbon cycle, plays a crucial role in regulating atmospheric carbon dioxide concentrations and climate. Therefore, it is essential to constrain the importance of marine carbon cycle feedbacks on global warming and ocean acidification. Arguably, the most important single component of the ocean's carbon cycle is the so-called "biological carbon pump". It transports carbon that is fixed in the light-flooded surface layer of the ocean to the deep ocean and the surface sediment, where it is degraded/dissolved or finally buried in the deep sediments. Over the past decade, progress has been made in understanding different factors that control the efficiency of the biological carbon pump and their feedbacks on the global carbon cycle and climate (i.e. ballasting = ocean acidification feedback; temperature dependant organic matter degradation = global warming feedback; organic matter sulphurisation = anoxia/euxinia feedback). Nevertheless, many uncertainties concerning the interplay of these processes and/or their relative significance remain. In addition, current Earth System Models tend to employ empirical and static parameterisations of the biological pump. As these parametric representations are derived from a limited set of present-day observations, their ability to represent carbon cycle feedbacks under changing climate conditions is limited. The aim of my research is to combine past carbon cycling information with a spatially resolved global biogeochemical model to constrain the functioning of the biological pump and to base its mathematical representation on a more mechanistic approach. Here, I will discuss important aspects that control the efficiency of the ocean's biological carbon pump, review how these processes of first order importance are mathematically represented in existing Earth system Models of Intermediate Complexity (EMIC) and distinguish different approaches to approximate

12 CFR 347.108 - Portfolio investments.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Portfolio investments. 347.108 Section 347.108... INTERNATIONAL BANKING § 347.108 Portfolio investments. (a) Portfolio investments. If a bank, directly or indirectly, acquires or holds an equity interest in a foreign organization as a portfolio investment and the...

Experimental strategies to assess the biological ramifications of multiple drivers of global ocean change-A review.

Science.gov (United States)

Boyd, Philip W; Collins, Sinead; Dupont, Sam; Fabricius, Katharina; Gattuso, Jean-Pierre; Havenhand, Jonathan; Hutchins, David A; Riebesell, Ulf; Rintoul, Max S; Vichi, Marcello; Biswas, Haimanti; Ciotti, Aurea; Gao, Kunshan; Gehlen, Marion; Hurd, Catriona L; Kurihara, Haruko; McGraw, Christina M; Navarro, Jorge M; Nilsson, Göran E; Passow, Uta; Pörtner, Hans-Otto

2018-06-01

Marine life is controlled by multiple physical and chemical drivers and by diverse ecological processes. Many of these oceanic properties are being altered by climate change and other anthropogenic pressures. Hence, identifying the influences of multifaceted ocean change, from local to global scales, is a complex task. To guide policy-making and make projections of the future of the marine biosphere, it is essential to understand biological responses at physiological, evolutionary and ecological levels. Here, we contrast and compare different approaches to multiple driver experiments that aim to elucidate biological responses to a complex matrix of ocean global change. We present the benefits and the challenges of each approach with a focus on marine research, and guidelines to navigate through these different categories to help identify strategies that might best address research questions in fundamental physiology, experimental evolutionary biology and community ecology. Our review reveals that the field of multiple driver research is being pulled in complementary directions: the need for reductionist approaches to obtain process-oriented, mechanistic understanding and a requirement to quantify responses to projected future scenarios of ocean change. We conclude the review with recommendations on how best to align different experimental approaches to contribute fundamental information needed for science-based policy formulation. © 2018 John Wiley & Sons Ltd.

Portfolios in Saudi medical colleges

Science.gov (United States)

Fida, Nadia M.; Shamim, Muhammad S.

2016-01-01

Over recent decades, the use of portfolios in medical education has evolved, and is being applied in undergraduate and postgraduate programs worldwide. Portfolios, as a learning process and method of documenting and assessing learning, is supported as a valuable tool by adult learning theories that stress the need for learners to be self-directed and to engage in experiential learning. Thoughtfully implemented, a portfolio provides learning experiences unequaled by any single learning tool. The credibility (validity) and dependability (reliability) of assessment through portfolios have been questioned owing to its subjective nature; however, methods to safeguard these features have been described in the literature. This paper discusses some of this literature, with particular attention to the role of portfolios in relation to self-reflective learning, provides an overview of current use of portfolios in undergraduate medical education in Saudi Arabia, and proposes research-based guidelines for its implementation and other similar contexts. PMID:26905344

Portfolio Analysis for Vector Calculus

Science.gov (United States)

Kaplan, Samuel R.

2015-01-01

Classic stock portfolio analysis provides an applied context for Lagrange multipliers that undergraduate students appreciate. Although modern methods of portfolio analysis are beyond the scope of vector calculus, classic methods reinforce the utility of this material. This paper discusses how to introduce classic stock portfolio analysis in a…

Optimal Portfolios in Wishart Models and Effects of Discrete Rebalancing on Portfolio Distribution and Strategy Selection

OpenAIRE

Li, Zejing

2012-01-01

This dissertation is mainly devoted to the research of two problems - the continuous-time portfolio optimization in different Wishart models and the effects of discrete rebalancing on portfolio wealth distribution and optimal portfolio strategy.

Using Electronic Portfolios

Science.gov (United States)

Page, Deb

2012-01-01

The digitized collections of artifacts known as electronic portfolios are creating solutions to a variety of performance improvement needs in ways that are cost-effective and improve both individual and group learning and performance. When social media functionality is embedded in e-portfolios, the tools support collaboration, social learning,…

Portfolios dominating indices: Optimization with second-order stochastic dominance constraints vs. minimum and mean variance portfolios

OpenAIRE

Keçeci, Neslihan Fidan; Kuzmenko, Viktor; Uryasev, Stan

2016-01-01

The paper compares portfolio optimization with the Second-Order Stochastic Dominance (SSD) constraints with mean-variance and minimum variance portfolio optimization. As a distribution-free decision rule, stochastic dominance takes into account the entire distribution of return rather than some specific characteristic, such as variance. The paper is focused on practical applications of the portfolio optimization and uses the Portfolio Safeguard (PSG) package, which has precoded modules for op...

Portfolios Dominating Indices: Optimization with Second-Order Stochastic Dominance Constraints vs. Minimum and Mean Variance Portfolios

OpenAIRE

Neslihan Fidan Keçeci; Viktor Kuzmenko; Stan Uryasev

2016-01-01

The paper compares portfolio optimization with the Second-Order Stochastic Dominance (SSD) constraints with mean-variance and minimum variance portfolio optimization. As a distribution-free decision rule, stochastic dominance takes into account the entire distribution of return rather than some specific characteristic, such as variance. The paper is focused on practical applications of the portfolio optimization and uses the Portfolio Safeguard (PSG) package, which has precoded modules for op...

Portfolio i erhvervsuddannelserne

DEFF Research Database (Denmark)

2008-01-01

Materialet kombinerer korte film med introducerende tekster og belyser fra forskellige vinkler, hvordan portfolio kan bruges som evalueringsmetode i erhvervsuddannelserne. Udgiver: Undervisningsministeriet Udgivelsessted: Pub.uvm.dk......Materialet kombinerer korte film med introducerende tekster og belyser fra forskellige vinkler, hvordan portfolio kan bruges som evalueringsmetode i erhvervsuddannelserne. Udgiver: Undervisningsministeriet Udgivelsessted: Pub.uvm.dk...

Portfolio Management

Science.gov (United States)

Duncan, Sharon L.

2011-01-01

Enterprise Business Information Services Division (EBIS) supports the Laboratory and its functions through the implementation and support of business information systems on behalf of its business community. EBIS Five Strategic Focus Areas: (1) Improve project estimating, planning and delivery capability (2) Improve maintainability and sustainability of EBIS Application Portfolio (3) Leap forward in IT Leadership (4) Comprehensive Talent Management (5) Continuous IT Security Program. Portfolio Management is a strategy in which software applications are managed as assets

From the microscope to the macroscopic: changing from the bench to portfolio management.

Science.gov (United States)

Sachs, Michael

2017-11-01

A role in portfolio management is ideal for individuals who enjoy tackling challenges that have both technical and business components. Portfolio management provides objective insights and analytics to support research and development decision making and planning. Successful practitioners usually have strong analytical abilities developed from a background in either science or business. Portfolio managers often advise key decision makers at both the team and senior management level and thus require robust oral, written, and interpersonal communication skills. Day-to-day tasks are rarely the same, and comfort with change and the unknown is essential. Here I will discuss my experience as a portfolio manager in a larger biopharmaceutical company and the skills from academic research I leveraged to make the transition. © 2017 Sachs. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Advancing Ocean Acidification Biology Using Durafet® pH Electrodes

Directory of Open Access Journals (Sweden)

Lydia Kapsenberg

2017-10-01

Full Text Available Research assessing the biological impacts of global ocean change often requires a burdensome characterization of seawater carbonate chemistry. For laboratory-based ocean acidification research, this impedes the scope of experimental design. Honeywell Durafet® III pH electrodes provide precise and continuous seawater pH measurements. In addition to use in oceanographic sensor packages, Durafets can also be used in the laboratory to track and control seawater treatments via Honeywell Universal Dual Analyzers (UDAs. Here we provide performance data, instructions, and step-by-step recommendations for use of multiple UDA-Durafets. Durafet pH measurements were within ±0.005 units pHT of spectrophotometric measurements and agreement among eight Durafets was better than ±0.005 units pHT. These results indicate equal performance to Durafets in oceanographic sensor packages, but methods for calibration and quality control differ. Use of UDA-Durafets vastly improves time-course documentation of experimental conditions and reduces person-hours dedicated to this activity. Due to the versatility of integrating Durafets in laboratory seawater systems, this technology opens the door to advance the scale of questions that the ocean acidification research community aims to address.

Large portfolio risk management and optimal portfolio allocation with dynamic elliptical copulas

Directory of Open Access Journals (Sweden)

Jin Xisong

2018-02-01

Full Text Available Previous research has focused on the importance of modeling the multivariate distribution for optimal portfolio allocation and active risk management. However, existing dynamic models are not easily applied to high-dimensional problems due to the curse of dimensionality. In this paper, we extend the framework of the Dynamic Conditional Correlation/Equicorrelation and an extreme value approach into a series of Dynamic Conditional Elliptical Copulas. We investigate risk measures such as Value at Risk (VaR and Expected Shortfall (ES for passive portfolios and dynamic optimal portfolios using Mean-Variance and ES criteria for a sample of US stocks over a period of 10 years. Our results suggest that (1 Modeling the marginal distribution is important for dynamic high-dimensional multivariate models. (2 Neglecting the dynamic dependence in the copula causes over-aggressive risk management. (3 The DCC/DECO Gaussian copula and t-copula work very well for both VaR and ES. (4 Grouped t-copulas and t-copulas with dynamic degrees of freedom further match the fat tail. (5 Correctly modeling the dependence structure makes an improvement in portfolio optimization with respect to tail risk. (6 Models driven by multivariate t innovations with exogenously given degrees of freedom provide a flexible and applicable alternative for optimal portfolio risk management.

The Development of E-Portfolio Evaluation Criteria and Application to the Blackboard LMS E-Portfolio

Science.gov (United States)

McKenna, Gary F.; Stansfield, Mark H.

2012-01-01

The purpose of this paper is to develop e-portfolio evaluation criteria which will be used to review the Blackboard LMS e-portfolio being used at one Higher Education (HE) institution in the UK as evaluation criteria for reviewing e-portfolio provision does not exist in the literature. The approach taken was to initiate a wide literature search…

13 CFR 107.760 - How a change in size or activity of a Portfolio Concern affects the Licensee and the Portfolio...

Science.gov (United States)

2010-01-01

... of a Portfolio Concern affects the Licensee and the Portfolio Concern. 107.760 Section 107.760... § 107.760 How a change in size or activity of a Portfolio Concern affects the Licensee and the Portfolio Concern. (a) Effect on Licensee of a change in size of a Portfolio Concern. If a Portfolio Concern no...

Robust Active Portfolio Management

National Research Council Canada - National Science Library

Erdogan, E; Goldfarb, D; Iyengar, G

2006-01-01

... on the portfolio beta, and limits on cash and industry exposure. We show that the optimal portfolios can be computed by solving second-order cone programs -- a class of optimization problems with a worst case complexity (i.e...

Universal portfolios generated by the Bregman divergence

Science.gov (United States)

Tan, Choon Peng; Kuang, Kee Seng

2017-04-01

The Bregman divergence of two probability vectors is a stronger form of the f-divergence introduced by Csiszar. Two versions of the Bregman universal portfolio are presented by exploiting the mean-value theorem. The explicit form of the Bregman universal portfolio generated by a function of a convex polynomial is derived and studied empirically. This portfolio can be regarded as another generalized of the well-known Helmbold portfolio. By running the portfolios on selected stock-price data sets from the local stock exchange, it is shown that it is possible to increase the wealth of the investor by using the portfolios in investment.

Different Variants of Fundamental Portfolio

Directory of Open Access Journals (Sweden)

Tarczyński Waldemar

2014-06-01

Full Text Available The paper proposes the fundamental portfolio of securities. This portfolio is an alternative for the classic Markowitz model, which combines fundamental analysis with portfolio analysis. The method’s main idea is based on the use of the TMAI1 synthetic measure and, in limiting conditions, the use of risk and the portfolio’s rate of return in the objective function. Different variants of fundamental portfolio have been considered under an empirical study. The effectiveness of the proposed solutions has been related to the classic portfolio constructed with the help of the Markowitz model and the WIG20 market index’s rate of return. All portfolios were constructed with data on rates of return for 2005. Their effectiveness in 2006- 2013 was then evaluated. The studied period comprises the end of the bull market, the 2007-2009 crisis, the 2010 bull market and the 2011 crisis. This allows for the evaluation of the solutions’ flexibility in various extreme situations. For the construction of the fundamental portfolio’s objective function and the TMAI, the study made use of financial and economic data on selected indicators retrieved from Notoria Serwis for 2005.

A Mean variance analysis of arbitrage portfolios

Science.gov (United States)

Fang, Shuhong

2007-03-01

Based on the careful analysis of the definition of arbitrage portfolio and its return, the author presents a mean-variance analysis of the return of arbitrage portfolios, which implies that Korkie and Turtle's results ( B. Korkie, H.J. Turtle, A mean-variance analysis of self-financing portfolios, Manage. Sci. 48 (2002) 427-443) are misleading. A practical example is given to show the difference between the arbitrage portfolio frontier and the usual portfolio frontier.

Patent portfolio management: literature review and a proposed model.

Science.gov (United States)

Conegundes De Jesus, Camila Kiyomi; Salerno, Mario Sergio

2018-05-09

Patents and patent portfolios are gaining attention in the last decades, from the called 'pro-patent era' to the recent billionaire transactions involving patent portfolios. The field is growing in importance, both theoretically and practically and despite having substantial literature on new product development portfolio management, we have not found an article relating this theory to patent portfolios. Areas covered: The paper develops a systematic literature review on patent portfolio management to organize the evolution and tendencies of patent portfolio management, highlighting distinctive features of patent portfolio management. Interview with IP manager of three life sciences companies, including a leading multinational group provided relevant information about patent portfolio management. Expert opinion: Based on the systematic literature review on portfolio management, more specifically, on new product development portfolio theory, and interview the paper proposes the paper proposes a reference model to manage patent portfolios. The model comprises four stages aligned with the three goals of the NPD portfolio management: 1 - Linking strategy of the Company's NPD Portfolio to Patent Portfolio; 2 - Balancing the portfolio in buckets; 3 - Patent Valuation (maximizing valuation); 4 - Regularly reviewing the patent portfolio.

Ancient clam gardens, traditional management portfolios, and the resilience of coupled human-ocean systems

Directory of Open Access Journals (Sweden)

Julia Jackley

2016-12-01

Full Text Available Indigenous communities have actively managed their environments for millennia using a diversity of resource use and conservation strategies. Clam gardens, ancient rock-walled intertidal beach terraces, represent one example of an early mariculture technology that may have been used to improve food security and confer resilience to coupled human-ocean systems. We surveyed a coastal landscape for evidence of past resource use and management to gain insight into ancient resource stewardship practices on the central coast of British Columbia, Canada. We found that clam gardens are embedded within a diverse portfolio of resource use and management strategies and were likely one component of a larger, complex resource management system. We compared clam diversity, density, recruitment, and biomass in three clam gardens and three unmodified nonwalled beaches. Evidence suggests that butter clams (Saxidomus gigantea had 1.96 times the biomass and 2.44 times the density in clam gardens relative to unmodified beaches. This was due to a reduction in beach slope and thus an increase in the optimal tidal range where clams grow and survive best. The most pronounced differences in butter clam density between nonwalled beaches and clam gardens were found at high tidal elevations at the top of the beach. Finally, clam recruits (0.5-2 mm in length tended to be greater in clam gardens compared to nonwalled beaches and may be attributed to the addition of shell hash by ancient people, which remains on the landscape today. As part of a broader social-ecological system, clam garden sites were among several modifications made by humans that collectively may have conferred resilience to past communities by providing reliable and diverse access to food resources.

Purchasing portfolio usage and purchasing sophistication

NARCIS (Netherlands)

Gelderman, C.J.; Weele, van A.J.

2005-01-01

Purchasing portfolio models have caused considerable controversy in literature. Many advantages and disadvantages have been put forward, revealing a strong disagreement on the merits of portfolio models. This study addresses the question whether or not the use of purchasing portfolio models should

Quantifying pCO2 in biological ocean acidification experiments: A comparison of four methods.

Science.gov (United States)

Watson, Sue-Ann; Fabricius, Katharina E; Munday, Philip L

2017-01-01

Quantifying the amount of carbon dioxide (CO2) in seawater is an essential component of ocean acidification research; however, equipment for measuring CO2 directly can be costly and involve complex, bulky apparatus. Consequently, other parameters of the carbonate system, such as pH and total alkalinity (AT), are often measured and used to calculate the partial pressure of CO2 (pCO2) in seawater, especially in biological CO2-manipulation studies, including large ecological experiments and those conducted at field sites. Here we compare four methods of pCO2 determination that have been used in biological ocean acidification experiments: 1) Versatile INstrument for the Determination of Total inorganic carbon and titration Alkalinity (VINDTA) measurement of dissolved inorganic carbon (CT) and AT, 2) spectrophotometric measurement of pHT and AT, 3) electrode measurement of pHNBS and AT, and 4) the direct measurement of CO2 using a portable CO2 equilibrator with a non-dispersive infrared (NDIR) gas analyser. In this study, we found these four methods can produce very similar pCO2 estimates, and the three methods often suited to field-based application (spectrophotometric pHT, electrode pHNBS and CO2 equilibrator) produced estimated measurement uncertainties of 3.5-4.6% for pCO2. Importantly, we are not advocating the replacement of established methods to measure seawater carbonate chemistry, particularly for high-accuracy quantification of carbonate parameters in seawater such as open ocean chemistry, for real-time measures of ocean change, nor for the measurement of small changes in seawater pCO2. However, for biological CO2-manipulation experiments measuring differences of over 100 μatm pCO2 among treatments, we find the four methods described here can produce similar results with careful use.

Household portfolios and implicit risk aversion

NARCIS (Netherlands)

Bucciol, A.; Miniaci, R.

2008-01-01

We derive from a sample of US households the distribution of the risk aversion implicit in their portfolio choice. Our estimate minimizes the distance between the certainty equivalent return generated with observed portfolios and portfolios that are optimal in a mean-variance framework. Taking into

Hierarchical Portfolio Management: Theory and Applications

NARCIS (Netherlands)

H. Ning (Haikun)

2007-01-01

textabstractUnder his own preference, how should an investor coordinate the asset managers such that his aggregated portfolio is optimized? The efficiency of each managed sub portfolio and the aggregation of all the sub portfolios are the 2 main underlying problems considered in this dissertation.

Quantitative investment strategies and portfolio management

NARCIS (Netherlands)

Guo, J.

2012-01-01

This book contains three essays on alternative investments and portfolio management. Taking from a portfolio investor’s perspective, the first essay analyzes the portfolio implication of investing in hedge funds when there is a hedge fund lockup period. The second essay studies the investment

AFSC/RACE/GAP/Conrath: Notes on the Reproductive Biology of Female Salmon Sharks in the Eastern North Pacific Ocean

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Little information has previously been published on the reproductive biology of the salmon shark in the Eastern North Pacific ocean. This data set incorporates basic...

Project Portfolio Management Applications Testing

OpenAIRE

Paul POCATILU

2006-01-01

Many IT companies are running project simultaneously. In order to achieve the best results, they have to group to the project in portfolios, and to use specific software that helps to manage them. Project portfolio management applications have a high degree of complexity and they are very important for the companies that are using it. This paper focuses on some characteristics of the testing process for project portfolio management applications

Analysis of the Capability Portfolio Review (CPR)

Science.gov (United States)

2014-06-01

10  2.4.1.1.  The Basics of Modern Portfolio Theory ...of Modern Portfolio Theory Much of modern portfolio management has been motivated by the influential work of Harry Markowitz (Markowitz, 1952) and...unsystematic risk associated with individual stocks, leaving only the generally market risk (Walls, 2004). The basic assumption of modern portfolio theory is

Project Portfolio Management Applications Testing

Directory of Open Access Journals (Sweden)

Paul POCATILU

2006-01-01

Full Text Available Many IT companies are running project simultaneously. In order to achieve the best results, they have to group to the project in portfolios, and to use specific software that helps to manage them. Project portfolio management applications have a high degree of complexity and they are very important for the companies that are using it. This paper focuses on some characteristics of the testing process for project portfolio management applications

Portfolio insurance using traded options

OpenAIRE

Machado-Santos, Carlos

2001-01-01

Literature concerning the institutional use of options indicates that the main purpose of option trading is to provide investors with the opportunity to create return distributions previously unavailable, considering that options provide the means to manipulate portfolio returns. In such a context, this study intends to analyse the returns of insured portfolios generated by hedging strategies on underlying stock portfolios. Because dynamic hedging is too expensive, we have hedged the stock po...

On the role of atmospheric forcing on upper ocean physics in the Southern Ocean and biological impacts

Science.gov (United States)

Carranza, Magdalena M.

The Southern Ocean (SO) plays a key role in regulating climate by absorbing nearly half of anthropogenic carbon dioxide (CO2). Both physical and biogeochemical processes contribute to the net CO2 sink. As a result of global warming and ozone depletion, westerly winds have increased, with consequences for upper ocean physics but little is known on how primary producers are expected to respond to changes in atmospheric forcing. This thesis addresses the impact of atmospheric forcing on upper ocean dynamics and phytoplankton bloom development in the SO on synoptic storm scales, combining a broad range of observations derived from satellites, reanalysis, profiling floats and Southern elephant seals. On atmospheric synoptic timescales (2-10 days), relevant for phytoplankton growth and accumulation, wind speed has a larger impact on satellite Chl-a variability than surface heat fluxes or wind stress curl. In summer, strong winds are linked to deep mixed layers, cold sea surface temperatures and enhanced satellite chlorophyll-a (Chl-a), which suggest wind-driven entrainment plays a role in sustaining phytoplankton blooms at the surface. Subsurface bio-optical data from floats and seals reveal deep Chl-a fluorescence maxima (DFM) are ubiquitous in summer and tend to sit at the base of the mixed layer, but can occur in all seasons. The fact that wind speed and Chl-a correlations are maximal at zero lag time (from daily data) and incubation experiments indicate phytoplankton growth occurs 3-4 days after iron addition, suggests high winds in summer entrain Chl-a from a subsurface maximum. Vertical profiles also reveal Chl-a fluorescence unevenness within hydrographically defined mixed layers, suggesting the biological timescales of adaptation through the light gradient (i.e. growth and/or photoacclimation) are often faster than mixing timescales, and periods of quiescence between storms are long enough for biological gradients to form within the homogeneous layer in density

Minimum Variance Portfolios in the Brazilian Equity Market

Directory of Open Access Journals (Sweden)

Alexandre Rubesam

2013-03-01

Full Text Available We investigate minimum variance portfolios in the Brazilian equity market using different methods to estimate the covariance matrix, from the simple model of using the sample covariance to multivariate GARCH models. We compare the performance of the minimum variance portfolios to those of the following benchmarks: (i the IBOVESPA equity index, (ii an equally-weighted portfolio, (iii the maximum Sharpe ratio portfolio and (iv the maximum growth portfolio. Our results show that the minimum variance portfolio has higher returns with lower risk compared to the benchmarks. We also consider long-short 130/30 minimum variance portfolios and obtain similar results. The minimum variance portfolio invests in relatively few stocks with low βs measured with respect to the IBOVESPA index, being easily replicable by individual and institutional investors alike.

PSN: Portfolio Social Network

DEFF Research Database (Denmark)

Cortes, Jordi Magrina; Nizamani, Sarwat; Memon, Nasrullah

2014-01-01

In this paper we present a web-based information system which is a portfolio social network (PSN) that provides solutions to the recruiters and job seekers. The proposed system enables users to create portfolio so that he/she can add his specializations with piece of code if any specifically...

Sygeplejestuderendes brug af portfolio i klinisk undervisning

DEFF Research Database (Denmark)

Hjorth, Anne Charlotte Overgaard; Bruhn, Helle

2014-01-01

Brugen af portfolio var mangelfuld, men et udviklingsprojekt i samarbejde med den kommunale sygepleje motiverede både sygeplejestuderende og kliniske vejledere til at anvende læringsdelen af portfolio aktivt.......Brugen af portfolio var mangelfuld, men et udviklingsprojekt i samarbejde med den kommunale sygepleje motiverede både sygeplejestuderende og kliniske vejledere til at anvende læringsdelen af portfolio aktivt....

Cluster analysis for portfolio optimization

OpenAIRE

Vincenzo Tola; Fabrizio Lillo; Mauro Gallegati; Rosario N. Mantegna

2005-01-01

We consider the problem of the statistical uncertainty of the correlation matrix in the optimization of a financial portfolio. We show that the use of clustering algorithms can improve the reliability of the portfolio in terms of the ratio between predicted and realized risk. Bootstrap analysis indicates that this improvement is obtained in a wide range of the parameters N (number of assets) and T (investment horizon). The predicted and realized risk level and the relative portfolio compositi...

Constant Proportion Portfolio Insurance

DEFF Research Database (Denmark)

Jessen, Cathrine

2014-01-01

on the theme, originally proposed by Fischer Black. In CPPI, a financial institution guarantees a floor value for the “insured” portfolio and adjusts the stock/bond mix to produce a leveraged exposure to the risky assets, which depends on how far the portfolio value is above the floor. Plain-vanilla portfolio...... insurance largely died with the crash of 1987, but CPPI is still going strong. In the frictionless markets of finance theory, the issuer’s strategy to hedge its liability under the contract is clear, but in the real world with transactions costs and stochastic jump risk, the optimal strategy is less obvious...

Validity of the Learning Portfolio: Analysis of a Portfolio Proposal for the University

Science.gov (United States)

Gregori-Giralt, Eva; Menéndez-Varela, José Luis

2015-01-01

Validity is a central issue in portfolio-based assessment. This empirical study used a quantitative approach to analyse the validity of the inferences drawn from a disciplinary course work portfolio assessment comprising profession-specific and learning competencies. The study also examined the problems involved in the development of the…

Performance of the reverse Helmbold universal portfolio

Science.gov (United States)

Tan, Choon Peng; Kuang, Kee Seng; Lee, Yap Jia

2017-04-01

The universal portfolio is an important investment strategy in a stock market where no stochastic model is assumed for the stock prices. The zero-gradient set of the objective function estimating the next-day portfolio which contains the reverse Kullback-Leibler order-alpha divergence is considered. From the zero-gradient set, the explicit, reverse Helmbold universal portfolio is obtained. The performance of the explicit, reverse Helmbold universal portfolio is studied by running them on some stock-price data sets from the local stock exchange. It is possible to increase the wealth of the investor by using these portfolios in investment.

Æstetik og portfolio

DEFF Research Database (Denmark)

Hyldahl, Kirsten Kofod; Sams, Pernille; Egelund, Karen Stine

2017-01-01

Nærværende artikel præsenterer resultaterne af udviklingsprojektet ”Portfolio og æstetik” på pædagoguddannelsen i Hjørring. Projektet har til formål, gennem æstetisk formsprog, at stilladsere og fastholde de studerendes læreprocesser samt udvikle og implementere portfolio i studieaktiviteter på...

Specific patterns in portfolio analysis

Directory of Open Access Journals (Sweden)

Gabriela Victoria ANGHELACHE

2013-11-01

Full Text Available In the mid-twentieth century, under an unprecedented growth of the business of trading in securities, the need to provide a modern framework for assessing the performance of portfolios of financial instruments was felt. To that effect, it is noted that over this period, more and more economists have attempted to develop statistical mathematical models that ensure the evaluation of profitability and portfolio risk securities. These models are considered to be part of "the modern portfolio theory".

Modern Portfolio Theory: Some Main Results

OpenAIRE

Müller, Heinz H.

2017-01-01

This article summarizes some main results in modern portfolio theory. First, the Markowitz approach is presented. Then the capital asset pricing model is derived and its empirical testability is discussed. Afterwards Neumann-Morgenstern utility theory is applied to the portfolio problem. Finally, it is shown how optimal risk allocation in an economy may lead to portfolio insurance

The Role of Agribusiness Assets in Investment Portfolios

OpenAIRE

Johnson, Michael; Malcolm, Bill; O'Connor, Ian

2006-01-01

Investment in agribusiness assets has grown significantly in recent years. The question of interest is whether including agribusiness assets in investment portfolios provide benefits. The effects of diversification by including agribusiness assets in two investment portfolios, a mixed asset portfolio and a diversified share portfolio was investigated using Markowitz’s (1952) Modern Portfolio Theory (MPT) of mean-variance optimization. To measure the performance of agribusiness assets, an in...

Performance of salmon fishery portfolios across western North America

Science.gov (United States)

Griffiths, Jennifer R; Schindler, Daniel E; Armstrong, Jonathan B; Scheuerell, Mark D; Whited, Diane C; Clark, Robert A; Hilborn, Ray; Holt, Carrie A; Lindley, Steven T; Stanford, Jack A; Volk, Eric C

2014-01-01

Quantifying the variability in the delivery of ecosystem services across the landscape can be used to set appropriate management targets, evaluate resilience and target conservation efforts. Ecosystem functions and services may exhibit portfolio-type dynamics, whereby diversity within lower levels promotes stability at more aggregated levels. Portfolio theory provides a framework to characterize the relative performance among ecosystems and the processes that drive differences in performance. We assessed Pacific salmon Oncorhynchus spp. portfolio performance across their native latitudinal range focusing on the reliability of salmon returns as a metric with which to assess the function of salmon ecosystems and their services to humans. We used the Sharpe ratio (e.g. the size of the total salmon return to the portfolio relative to its variability (risk)) to evaluate the performance of Chinook and sockeye salmon portfolios across the west coast of North America. We evaluated the effects on portfolio performance from the variance of and covariance among salmon returns within each portfolio, and the association between portfolio performance and watershed attributes. We found a positive latitudinal trend in the risk-adjusted performance of Chinook and sockeye salmon portfolios that also correlated negatively with anthropogenic impact on watersheds (e.g. dams and land-use change). High-latitude Chinook salmon portfolios were on average 2·5 times more reliable, and their portfolio risk was mainly due to low variance in the individual assets. Sockeye salmon portfolios were also more reliable at higher latitudes, but sources of risk varied among the highest performing portfolios. Synthesis and applications. Portfolio theory provides a straightforward method for characterizing the resilience of salmon ecosystems and their services. Natural variability in portfolio performance among undeveloped watersheds provides a benchmark for restoration efforts. Locally and regionally

Performance of salmon fishery portfolios across western North America.

Science.gov (United States)

Griffiths, Jennifer R; Schindler, Daniel E; Armstrong, Jonathan B; Scheuerell, Mark D; Whited, Diane C; Clark, Robert A; Hilborn, Ray; Holt, Carrie A; Lindley, Steven T; Stanford, Jack A; Volk, Eric C

2014-12-01

Quantifying the variability in the delivery of ecosystem services across the landscape can be used to set appropriate management targets, evaluate resilience and target conservation efforts. Ecosystem functions and services may exhibit portfolio-type dynamics, whereby diversity within lower levels promotes stability at more aggregated levels. Portfolio theory provides a framework to characterize the relative performance among ecosystems and the processes that drive differences in performance. We assessed Pacific salmon Oncorhynchus spp. portfolio performance across their native latitudinal range focusing on the reliability of salmon returns as a metric with which to assess the function of salmon ecosystems and their services to humans. We used the Sharpe ratio (e.g. the size of the total salmon return to the portfolio relative to its variability (risk)) to evaluate the performance of Chinook and sockeye salmon portfolios across the west coast of North America. We evaluated the effects on portfolio performance from the variance of and covariance among salmon returns within each portfolio, and the association between portfolio performance and watershed attributes. We found a positive latitudinal trend in the risk-adjusted performance of Chinook and sockeye salmon portfolios that also correlated negatively with anthropogenic impact on watersheds (e.g. dams and land-use change). High-latitude Chinook salmon portfolios were on average 2·5 times more reliable, and their portfolio risk was mainly due to low variance in the individual assets. Sockeye salmon portfolios were also more reliable at higher latitudes, but sources of risk varied among the highest performing portfolios. Synthesis and applications . Portfolio theory provides a straightforward method for characterizing the resilience of salmon ecosystems and their services. Natural variability in portfolio performance among undeveloped watersheds provides a benchmark for restoration efforts. Locally and regionally

Ant colony algorithm for clustering in portfolio optimization

Science.gov (United States)

Subekti, R.; Sari, E. R.; Kusumawati, R.

2018-03-01

This research aims to describe portfolio optimization using clustering methods with ant colony approach. Two stock portfolios of LQ45 Indonesia is proposed based on the cluster results obtained from ant colony optimization (ACO). The first portfolio consists of assets with ant colony displacement opportunities beyond the defined probability limits of the researcher, where the weight of each asset is determined by mean-variance method. The second portfolio consists of two assets with the assumption that each asset is a cluster formed from ACO. The first portfolio has a better performance compared to the second portfolio seen from the Sharpe index.

Financial Advice and Individual Investor Portfolio Performance

NARCIS (Netherlands)

Kramer, M.M.

2012-01-01

This paper investigates whether financial advisers add value to individual investors portfolio decisions by comparing portfolios of advised and self-directed (execution-only) Dutch individual investors. The results indicate significant differences in characteristics and portfolios between these

Decentralized Portfolio Management

Directory of Open Access Journals (Sweden)

Benjamin Miranda Tabak

2003-12-01

Full Text Available We use a mean-variance model to analyze the problem of decentralized portfolio management. We find the solution for the optimal portfolio allocation for a head trader operating in n different markets, which is called the optimal centralized portfolio. However, as there are many traders specialized in different markets, the solution to the problem of optimal decentralized allocation should be different from the centralized case. In this paper we derive conditions for the solutions to be equivalent. We use multivariate normal returns and a negative exponential function to solve the problem analytically. We generate the equivalence of solutions by assuming that different traders face different interest rates for borrowing and lending. This interest rate is dependent on the ratio of the degrees of risk aversion of the trader and the head trader, on the excess return, and on the correlation between asset returns.

Optimal Portfolio Rebalancing Strategy : Evidence from Finnish Stocks

OpenAIRE

Savage, Akinwunmi

2010-01-01

Portfolio rebalancing is an established concept in portfolio management and investing generally. Assets within a portfolio have different return and risk prospects, and this inevitably leads them to drift away from their initial allocation weights overtime. Portfolio rebalancing is arguably the only method by which such assets can be reset to their initial weights, thus ensuring the portfolio reflects the risk appetite of the investor. Like many other concepts and practices in finance, portfo...

The size distribution of marine atmospheric aerosol with regard to primary biological aerosol particles over the South Atlantic Ocean

Science.gov (United States)

Matthias-Maser, Sabine; Brinkmann, Jutta; Schneider, Wilhelm

The marine atmosphere is characterized by particles which originate from the ocean and by those which reached the air by advection from the continent. The bubble-burst mechanism produces both sea salt as well as biological particles. The following article describes the determination of the size distribution of marine aerosol particles with special emphasis on the biological particles. Th data were obtained on three cruises with the German Research Vessel "METEOR" crossing the South Atlantic Ocean. The measurements showed that biological particles amount to 17% in number and 10% in volume concentration. Another type of particle became obvious in the marine atmosphere, the biologically contaminated particle, i.e. particles which consist partly (approximately up to one-third) of biological matter. Their concentration in the evaluated size class ( r>2 μm) is higher than the concentration of the pure biological particles. The concentrations vary over about one to two orders of magnitude during all cruises.

A Relationship Strategy Perspective on Relationship Portfolios

DEFF Research Database (Denmark)

Ritter, Thomas; Andersen, Henrik

2014-01-01

The paper develops a three-dimensional portfolio model for business relationships which distinguishes among six different categories. Based on assessments of customer profitability, customer commitment, and growth potential, the positioning of a given customer relationship in the portfolio allows...... managers to determine appropriate customer relationship strategies and appropriate performance indicators. Results from applying the portfolio model are reported and managerial implications and future research are discussed.......The paper develops a three-dimensional portfolio model for business relationships which distinguishes among six different categories. Based on assessments of customer profitability, customer commitment, and growth potential, the positioning of a given customer relationship in the portfolio allows...

12 CFR 1252.1 - Enterprise portfolio holding criteria.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Enterprise portfolio holding criteria. 1252.1 Section 1252.1 Banks and Banking FEDERAL HOUSING FINANCE AGENCY ENTERPRISES PORTFOLIO HOLDINGS § 1252.1 Enterprise portfolio holding criteria. The Enterprises are required to comply with the portfolio holdings...

PRODUCT PORTFOLIO ANALYSIS - ARTHUR D. LITTLE MATRIX

Directory of Open Access Journals (Sweden)

Curmei Catalin Valeriu

2011-07-01

Full Text Available In recent decades we have witnessed an unseen dynamism among companies, which is explained by their desire to engage in more activities that provide a high level of development and diversification. Thus, as companies are diversifying more and more, their managers confront a number of challenges arising from the management of resources for the product portfolio and the low level of resources with which companies can identify, at a time. Responding to these challenges, over time were developed a series of analytical product portfolio methods through which managers can balance the sources of cash flows from the multiple products and also can identify the place and role of products, in strategic terms, within the product portfolio. In order to identify these methods the authors of the present paper have conducted a desk research in order to analyze the strategic marketing and management literature of the last 2 decades. Widely were studied a series of methods that are presented in the marketing and management literature as the main instruments used within the product portfolio strategic planning process. Among these methods we focused on the Arthur D. Little matrix. Thus the present paper has the purpose to outline the characteristics and strategic implications of the ADL matrix within a company’s product portfolio. After conducting this analysis we have found that restricting the product portfolio analysis to the A.D.L. matrix is not a very wise decision. The A.D.L. matrix among with other marketing tools of product portfolio analysis have some advantages and disadvantages and is trying to provide, at a time, a specific diagnosis of a company’s product portfolio. Therefore, the recommendation for the Romanian managers consists in a combined use of a wide range of tools and techniques for product portfolio analysis. This leads to a better understanding of the whole mix of product markets, included in portfolio analysis, the strategic position

METHODICAL BASES OF MANAGEMENT OF INSURANCE PORTFOLIO

Directory of Open Access Journals (Sweden)

Serdechna Yulia

2018-01-01

Full Text Available Introduction. Despite the considerable arsenal of developments in the issues of assessing the management of the insurance portfolio remains unresolved. In order to detail, specify and further systematize the indicators for the indicated evaluation, the publications of scientists are analyzed. The purpose of the study is to analyze existing methods by which it is possible to formulate and manage the insurance portfolio in order to achieve its balance, which will contribute to ensuring the financial reliability of the insurance company. Results. The description of the essence of the concept of “management of insurance portfolio”, as the application of actuarial methods and techniques to the combination of various insurance risks offered for insurance or are already part of the insurance portfolio, allowing to adjust the size and structure of the portfolio in order to ensure its financial stability, achievement the maximum level of income of an insurance organization, preservation of the value of its equity and financial security of insurance liabilities. It is determined that the main methods by which the insurer’s insurance portfolio can be formed and managed is the selection of risks; reinsurance operations that ensure diversification of risks; formation and placement of insurance reserves, which form the financial basis of insurance activities. The method of managing an insurance portfolio, which can be both active and passive, is considered. Conclusions. It is determined that the insurance portfolio is the basis on which all the activities of the insurer are based and which determines its financial stability. The combination of methods and technologies applied to the insurance portfolio is a management method that can be both active and passive and has a number of specific methods through which the insurer’s insurance portfolio can be formed and managed. It is substantiated that each insurance company aims to form an efficient and

Mean-Reverting Portfolio With Budget Constraint

Science.gov (United States)

Zhao, Ziping; Palomar, Daniel P.

2018-05-01

This paper considers the mean-reverting portfolio design problem arising from statistical arbitrage in the financial markets. We first propose a general problem formulation aimed at finding a portfolio of underlying component assets by optimizing a mean-reversion criterion characterizing the mean-reversion strength, taking into consideration the variance of the portfolio and an investment budget constraint. Then several specific problems are considered based on the general formulation, and efficient algorithms are proposed. Numerical results on both synthetic and market data show that our proposed mean-reverting portfolio design methods can generate consistent profits and outperform the traditional design methods and the benchmark methods in the literature.

Reliability of Portfolio: A Closer Look at Findings from Recent Publications

Science.gov (United States)

Oskay, Ozge Ozyalcin; Schallies, Michael; Morgil, Inci

2008-01-01

In this review article, conventional portfolio assessment and new developments in portfolio assessment are investigated. The concept of portfolio, portfolio building steps, contents of portfolio, evaluation of portfolio, advantages, disadvantages and concerns in using portfolio as well as validity and reliability of portfolio assessment are…

Vast Portfolio Selection with Gross-exposure Constraints().

Science.gov (United States)

Fan, Jianqing; Zhang, Jingjin; Yu, Ke

2012-01-01

We introduce the large portfolio selection using gross-exposure constraints. We show that with gross-exposure constraint the empirically selected optimal portfolios based on estimated covariance matrices have similar performance to the theoretical optimal ones and there is no error accumulation effect from estimation of vast covariance matrices. This gives theoretical justification to the empirical results in Jagannathan and Ma (2003). We also show that the no-short-sale portfolio can be improved by allowing some short positions. The applications to portfolio selection, tracking, and improvements are also addressed. The utility of our new approach is illustrated by simulation and empirical studies on the 100 Fama-French industrial portfolios and the 600 stocks randomly selected from Russell 3000.

Designing Modern Equity Portfolios

OpenAIRE

Ronald Jean Degen

2011-01-01

This aim of this paper is to describe possible ways of investing in equity; choosing the right stocks(among small-cap, large-cap, value, growth, and foreign) using fundamental analysis, defining their appropriate mix in the portfolios according to the desired return-risk profiles based on Markowitz?s modern portfolio theory, and using technical analysis to buy and sell them.

Student evaluations of the portfolio process.

Science.gov (United States)

Murphy, John E; Airey, Tatum C; Bisso, Andrea M; Slack, Marion K

2011-09-10

To evaluate pharmacy students' perceived benefits of the portfolio process and to gather suggestions for improving the process. A questionnaire was designed and administered to 250 first-, second-, and third-year pharmacy students at the University of Arizona College of Pharmacy. Although the objectives of the portfolio process were for students to understand the expected outcomes, understand the impact of extracurricular activities on attaining competencies, identify what should be learned, identify their strengths and weaknesses, and modify their approach to learning, overall students perceived the portfolio process as having less than moderate benefit. First-year students wanted more examples of portfolios while second- and third-year students suggested that more time with their advisor would be beneficial. The portfolio process will continue to be refined and efforts made to improve students' perceptions of the process as it is intended to develop the self-assessments skills they will need to improve their knowledge and professional skills throughout their pharmacy careers.

Portfolio optimization with skewness and kurtosis

Science.gov (United States)

Lam, Weng Hoe; Jaaman, Saiful Hafizah Hj.; Isa, Zaidi

2013-04-01

Mean and variance of return distributions are two important parameters of the mean-variance model in portfolio optimization. However, the mean-variance model will become inadequate if the returns of assets are not normally distributed. Therefore, higher moments such as skewness and kurtosis cannot be ignored. Risk averse investors prefer portfolios with high skewness and low kurtosis so that the probability of getting negative rates of return will be reduced. The objective of this study is to compare the portfolio compositions as well as performances between the mean-variance model and mean-variance-skewness-kurtosis model by using the polynomial goal programming approach. The results show that the incorporation of skewness and kurtosis will change the optimal portfolio compositions. The mean-variance-skewness-kurtosis model outperforms the mean-variance model because the mean-variance-skewness-kurtosis model takes skewness and kurtosis into consideration. Therefore, the mean-variance-skewness-kurtosis model is more appropriate for the investors of Malaysia in portfolio optimization.

Managing R&D Alliance Portfolios

DEFF Research Database (Denmark)

Engel Nielsen, Lars; Mahnke, Volker

2003-01-01

be observed in several companies engaged in the cross section of telecommunication and mobile technology where increased complexity magnifies managerial challenges. Drawing on modern portfolio theory, this paper offers a model for managing portfolios of R&D alliances. In particular, an analysis...

The Finite and Moving Order Multinomial Universal Portfolio

International Nuclear Information System (INIS)

Tan, Choon Peng; Pang, Sook Theng

2013-01-01

An upper bound for the ratio of wealths of the best constant -rebalanced portfolio to that of the multinomial universal portfolio is derived. The finite- order multinomial universal portfolios can reduce the implementation time and computer-memory requirements for computation. The improved performance of the finite-order portfolios on some selected local stock-price data sets is observed.

Correlation risk and optimal portfolio choice

OpenAIRE

Buraschi, Andrea; Porchia, Paolo; Trojani, Fabio

2010-01-01

We develop a new framework for multivariate intertemporal portfolio choice that allows us to derive optimal portfolio implications for economies in which the degree of correlation across industries, countries, or asset classes is stochastic. Optimal portfolios include distinct hedging components against both stochastic volatility and correlation risk. We find that the hedging demand is typically larger than in univariate models, and it includes an economically significant covariance hedging...

Essays on Rational Portfolio Theory

DEFF Research Database (Denmark)

Nielsen, Simon Ellersgaard

market prices, we findonly a very modest improvement in portfolio wealth over the corresponding strategy whichonly trades in bonds and stocks. Optimal Hedge Tracking Portfolios in a Limit Order Book. In this paper we developa control theoretic solution to the manner in which a portfolio manager optimally...... shouldtrack a targeted D, given that he wishes to hedge a short position in European call optionsthe underlying of which is traded in a limit order book. Specifically, we are interested in theinterplay between posting limit and market orders respectively: when should the portfoliomanager do what (and at what......’s theory of optimal portfolio selection for wealth maximisingagents. In this paper we present a systematic analysis of the optimal asset allocation in aderivative-free market for the Heston model, the 3/2 model, and a Fong Vasicek type model.Under the assumption that the market price of risk...

Digital Portfolio: a Strategy for Teachers Professional Development

Directory of Open Access Journals (Sweden)

R. Jans

2008-03-01

Full Text Available Teachers have to work with e-portfolio with theirstudents. This is a very demanding task because they neverwere educated with e-portfolio themselves. Therefore aEuropean Comenius project was submitted in 2005. In thisapproved project a whole week formation (april 2007 wasoffered to nineteen teachers from all over Europe. A yearlater they will meet again to see in what way the course hashad effects on their work with e-portfolio and students.Most interesting to notice was that the basic ICT-skills ofteachers are nowadays realized. However teachers are stillbusy with text and text-files. Rarely they uploadedmultimedia, like e.g. photo’s, video’s, youtube-movies, … intheir e-portfolio. The essential element of an e-portfolio, thepersonal and professional development plan, that forms thebackbone of the e-portfolio and offers the possibility tomake the e-portfolio an effective learning instrument wasunknown.

Parametric Portfolio Policies with Common Volatility Dynamics

DEFF Research Database (Denmark)

Ergemen, Yunus Emre; Taamouti, Abderrahim

A parametric portfolio policy function is considered that incorporates common stock volatility dynamics to optimally determine portfolio weights. Reducing dimension of the traditional portfolio selection problem significantly, only a number of policy parameters corresponding to first- and second......-order characteristics are estimated based on a standard method-of-moments technique. The method, allowing for the calculation of portfolio weight and return statistics, is illustrated with an empirical application to 30 U.S. industries to study the economic activity before and after the recent financial crisis....

Vast Portfolio Selection with Gross-exposure Constraints*

Science.gov (United States)

Fan, Jianqing; Zhang, Jingjin; Yu, Ke

2012-01-01

We introduce the large portfolio selection using gross-exposure constraints. We show that with gross-exposure constraint the empirically selected optimal portfolios based on estimated covariance matrices have similar performance to the theoretical optimal ones and there is no error accumulation effect from estimation of vast covariance matrices. This gives theoretical justification to the empirical results in Jagannathan and Ma (2003). We also show that the no-short-sale portfolio can be improved by allowing some short positions. The applications to portfolio selection, tracking, and improvements are also addressed. The utility of our new approach is illustrated by simulation and empirical studies on the 100 Fama-French industrial portfolios and the 600 stocks randomly selected from Russell 3000. PMID:23293404

Portfolio optimization retail investor

Directory of Open Access Journals (Sweden)

I. А. Kiseleva

2016-01-01

Full Text Available The article notes that the task of the investor's risk management is to, on the one hand, as much as possible to strive to achieve the criterion of risk level, and on the other hand, in any case not exceed it. Since the domestic theory of risk management is under development, the problem of the optimal ratio of "risk-income" becomes now of particular relevance. This article discusses the different distribution areas of the private investor in order to obtain the maximum profit. The analysis showed us the overall economic and political system of the country, as well as the legislative provision of guarantees to the investor. To obtain sufficient income and reduce losses it is important to maintain the optimum value found between the amount of the investor's risk and capital transactions. Model of optimal placement of funds led to the conclusion about inexpediency strong increase in the diversification of the investment portfolio (more than 10 different types of assets in the portfolio, since it increases the complexity of its practical form, while the portfolio characteristics are improved significantly. It is concluded that it is impossible to increase revenue without increasing the risk or reduce risk without reducing income. The analysis shows that there is no single best asset portfolio. It is impossible to increase revenue without increasing the risk or reduce risk without reducing income. Possible combination of the "riskincome" will depend on the objective function. Most diversified and bringing the best return per unit of risk, is a portfolio that contains the most risky assets.

Portfolio optimization and performance evaluation

DEFF Research Database (Denmark)

Juhl, Hans Jørn; Christensen, Michael

2013-01-01

Based on an exclusive business-to-business database comprising nearly 1,000 customers, the applicability of portfolio analysis is documented, and it is examined how such an optimization analysis can be used to explore the growth potential of a company. As opposed to any previous analyses, optimal...... customer portfolios are determined, and it is shown how marketing decision-makers can use this information in their marketing strategies to optimize the revenue growth of the company. Finally, our analysis is the first analysis which applies portfolio based methods to measure customer performance......, and it is shown how these performance measures complement the optimization analysis....

Marine Biology Activities. Ocean Related Curriculum Activities.

Science.gov (United States)

Pauls, John

The ocean affects all of our lives. Therefore, awareness of and information about the interconnections between humans and oceans are prerequisites to making sound decisions for the future. Project ORCA (Ocean Related Curriculum Activities) has developed interdisciplinary curriculum materials designed to meet the needs of students and teachers…

Using Electronic Portfolios for Second Language Assessment

Science.gov (United States)

Cummins, Patricia W.; Davesne, Celine

2009-01-01

Portfolio assessment as developed in Europe presents a learner-empowering alternative to computer-based testing. The authors present the European Language Portfolio (ELP) and its American adaptations, LinguaFolio and the Global Language Portfolio, as tools to be used with the Common European Framework of Reference for languages and the American…

Robust Portfolio Optimization Using Pseudodistances

Science.gov (United States)

2015-01-01

The presence of outliers in financial asset returns is a frequently occurring phenomenon which may lead to unreliable mean-variance optimized portfolios. This fact is due to the unbounded influence that outliers can have on the mean returns and covariance estimators that are inputs in the optimization procedure. In this paper we present robust estimators of mean and covariance matrix obtained by minimizing an empirical version of a pseudodistance between the assumed model and the true model underlying the data. We prove and discuss theoretical properties of these estimators, such as affine equivariance, B-robustness, asymptotic normality and asymptotic relative efficiency. These estimators can be easily used in place of the classical estimators, thereby providing robust optimized portfolios. A Monte Carlo simulation study and applications to real data show the advantages of the proposed approach. We study both in-sample and out-of-sample performance of the proposed robust portfolios comparing them with some other portfolios known in literature. PMID:26468948

Does health affect portfolio choice?

Science.gov (United States)

Love, David A; Smith, Paul A

2010-12-01

A number of recent studies find that poor health is empirically associated with a safer portfolio allocation. It is difficult to say, however, whether this relationship is truly causal. Both health status and portfolio choice are influenced by unobserved characteristics such as risk attitudes, impatience, information, and motivation, and these unobserved factors, if not adequately controlled for, can induce significant bias in the estimates of asset demand equations. Using the 1992-2006 waves of the Health and Retirement Study, we investigate how much of the connection between health and portfolio choice is causal and how much is due to the effects of unobserved heterogeneity. Accounting for unobserved heterogeneity with fixed effects and correlated random effects models, we find that health does not appear to significantly affect portfolio choice among single households. For married households, we find a small effect (about 2-3 percentage points) from being in the lowest of five self-reported health categories. Copyright © 2009 John Wiley & Sons, Ltd.

Robust Portfolio Optimization Using Pseudodistances.

Science.gov (United States)

Toma, Aida; Leoni-Aubin, Samuela

2015-01-01

The presence of outliers in financial asset returns is a frequently occurring phenomenon which may lead to unreliable mean-variance optimized portfolios. This fact is due to the unbounded influence that outliers can have on the mean returns and covariance estimators that are inputs in the optimization procedure. In this paper we present robust estimators of mean and covariance matrix obtained by minimizing an empirical version of a pseudodistance between the assumed model and the true model underlying the data. We prove and discuss theoretical properties of these estimators, such as affine equivariance, B-robustness, asymptotic normality and asymptotic relative efficiency. These estimators can be easily used in place of the classical estimators, thereby providing robust optimized portfolios. A Monte Carlo simulation study and applications to real data show the advantages of the proposed approach. We study both in-sample and out-of-sample performance of the proposed robust portfolios comparing them with some other portfolios known in literature.

The type k universal portfolio generated by the f-divergence

Science.gov (United States)

Tan, Choon Peng; Seng, Kuang Kee

2017-11-01

The logarithm of the estimated next-day wealth return is approximated by k terms of its Taylor series. The resulting Type k universal portfolio generated by the f -divergence is obtained. An implicit form of the portfolio is also obtained by exploiting the mean-value theorem. An empirical study of the performance of the portfolio is focused on the Type 2 Helmbold universal portfolio. A few generalizations of the Helmbold universal portfolio have recently been studied, namely the reverse Helmbold and the parametric Helmbold portfolios. This new type of portfolio can be regarded a contribution to the inventory of Helmbold related universal portfolios. It is verified experimentally that an investor's wealth can be significantly increased by using the Type 2 Helmbold portfolio in investment.

Model to Estimate Monthly Time Horizons for Application of DEA in Selection of Stock Portfolio and for Maintenance of the Selected Portfolio

Directory of Open Access Journals (Sweden)

José Claudio Isaias

2015-01-01

Full Text Available In the selecting of stock portfolios, one type of analysis that has shown good results is Data Envelopment Analysis (DEA. It, however, has been shown to have gaps regarding its estimates of monthly time horizons of data collection for the selection of stock portfolios and of monthly time horizons for the maintenance of a selected portfolio. To better estimate these horizons, this study proposes a model of mathematical programming binary of minimization of square errors. This model is the paper’s main contribution. The model’s results are validated by simulating the estimated annual return indexes of a portfolio that uses both horizons estimated and of other portfolios that do not use these horizons. The simulation shows that portfolios with both horizons estimated have higher indexes, on average 6.99% per year. The hypothesis tests confirm the statistically significant superiority of the results of the proposed mathematical model’s indexes. The model’s indexes are also compared with portfolios that use just one of the horizons estimated; here the indexes of the dual-horizon portfolios outperform the single-horizon portfolios, though with a decrease in percentage of statistically significant superiority.

ALPHA-BETA SEPARATION PORTFOLIO STRATEGIES FOR ISLAMIC FINANCE

Directory of Open Access Journals (Sweden)

Valentyn Khokhlov

2016-11-01

Full Text Available The purpose of this paper is to develop a mathematical alpha-beta separation model that can be used to create a core-satellite portfolio management strategy that complies with the principles of Islamic finance. Methodology. Core-satellite portfolio construction methodology is used to implement the alpha-beta separation approach, where the core part of the portfolio is managed using the tracking error minimization strategy, and the satellite part of the portfolio is managed using the mean-variance optimization strategy. Results of the portfolio dynamics clearly show that a significant amount of value was created by alpha-beta separation. The typical alpha ranges from 4% to 5.7%. The most aggressive portfolio strategies that allow short positions in the satellite portfolio work best with frequent rebalancing and benefit from the active bets. Smoothing technique that was introduced to decrease the portfolio turnover and stabilize its composition works better when active bets are less efficient, particularly with less frequent rebalancing. The best risk-return combinations are achieved with modest (3% to 10% allocation of the total portfolio to the satellite, and the remaining part (90% to 97% being managed in order to minimize the tracking error. Practical implications. The alpha-beta separation framework suggested in this paper can be used to enhance the portfolio management techniques for the hedge funds that operate under tight restrictions, particularly under the Islamic finance principles. The mathematical models developed in this paper allow practical implementation of the alphabeta separation concept. Originality/value. While the idea of alpha-beta separation existed in hedge fund management before, there was no comprehensive mathematical model under it, so its implementation was based on the ad hoc approach. This paper introduces such a mathematical model and demonstrates how portfolio managers can create value for their clients using it.

Renewable energy technology portfolio planning with scenario analysis: A case study for Taiwan

International Nuclear Information System (INIS)

Chen, T.-Y.; Yu, Oliver S.; Hsu, George Jyh-yih; Hsu, Fang-Ming; Sung, W.-N.

2009-01-01

This paper presents the results of a case study of applying a systematic and proven process of technology portfolio planning with the use of scenario analysis to renewable energy developments in Taiwan. The planning process starts with decision values of technology development based on a survey of society leaders. It then generates, based on expert opinions and literature search, a set of major technology alternatives, which in this study include: wind energy, photovoltaic, bio-energy, solar thermal power, ocean energy, and geothermal energy. Through a committee of technical experts with diversified professional backgrounds, the process in this study next constructs three scenarios ('Season in the Sun', 'More Desire than Energy', and 'Castle in the Air') to encompass future uncertainties in the relationships between the technology alternatives and the decision values. Finally, through a second committee of professionals, the process assesses the importance and risks of these alternative technologies and develops a general strategic plan for the renewable energy technology portfolio that is responsive and robust for the future scenarios. The most important contributions of this paper are the clear description of the systematic process of technology portfolio planning and scenario analysis, the detailed demonstration of their application through a case study on the renewable energy development in Taiwan, and the valuable results and insights gained from the application.

Portfolio Assessment: Production and Reduction of Complexity

DEFF Research Database (Denmark)

Keiding, Tina Bering; Qvortrup, Ane

2015-01-01

Over the last two decades, the education system has witnessed a shift from summative, product-oriented assessment towards formative, process-oriented assessment. Among the different learning and assessment initiatives introduced in the slipstream of this paradigmatic turn, the portfolio seems...... to have become one of the most popular. By re-describing the portfolio from a systems theoretical point of view, this article discusses established expectations of the portfolio in relation to transparency in learning, reflexivity and self-assessment. It shows that the majority of the literature deals...... with what-questions and that the portfolio is expected to handle a number of challenges with regard to the documentation of learning processes and achievements as well as the conditioning of learning activities. Furthermore, is becomes clear that descriptions of how the portfolio works are sparse. Based...

Performance of finite order distribution-generated universal portfolios

Science.gov (United States)

Pang, Sook Theng; Liew, How Hui; Chang, Yun Fah

2017-04-01

A Constant Rebalanced Portfolio (CRP) is an investment strategy which reinvests by redistributing wealth equally among a set of stocks. The empirical performance of the distribution-generated universal portfolio strategies are analysed experimentally concerning 10 higher volume stocks from different categories in Kuala Lumpur Stock Exchange. The time interval of study is from January 2000 to December 2015, which includes the credit crisis from September 2008 to March 2009. The performance of the finite-order universal portfolio strategies has been shown to be better than Constant Rebalanced Portfolio with some selected parameters of proposed universal portfolios.

Biological responses of sharks to ocean acidification.

Science.gov (United States)

Rosa, Rui; Rummer, Jodie L; Munday, Philip L

2017-03-01

Sharks play a key role in the structure of marine food webs, but are facing major threats due to overfishing and habitat degradation. Although sharks are also assumed to be at relatively high risk from climate change due to a low intrinsic rate of population growth and slow rates of evolution, ocean acidification (OA) has not, until recently, been considered a direct threat. New studies have been evaluating the potential effects of end-of-century elevated CO 2 levels on sharks and their relatives' early development, physiology and behaviour. Here, we review those findings and use a meta-analysis approach to quantify the overall direction and magnitude of biological responses to OA in the species of sharks that have been investigated to date. While embryo survival and development time are mostly unaffected by elevated CO 2 , there are clear effects on body condition, growth, aerobic potential and behaviour (e.g. lateralization, hunting and prey detection). Furthermore, studies to date suggest that the effects of OA could be as substantial as those due to warming in some species. A major limitation is that all past studies have involved relatively sedentary, benthic sharks that are capable of buccal ventilation-no studies have investigated pelagic sharks that depend on ram ventilation. Future research should focus on species with different life strategies (e.g. pelagic, ram ventilators), climate zones (e.g. polar regions), habitats (e.g. open ocean), and distinct phases of ontogeny in order to fully predict how OA and climate change will impact higher-order predators and therefore marine ecosystem dynamics. © 2017 The Author(s).

Reflection during Portfolio-Based Conversations

Science.gov (United States)

Oosterbaan, Anne E.; van der Schaaf, Marieke F.; Baartman, Liesbeth K. J.; Stokking, Karel M.

2010-01-01

This study aims to explore the relationship between the occurrence of reflection (and non-reflection) and thinking activities (e.g., orientating, selecting, analysing) during portfolio-based conversations. Analysis of 21 transcripts of portfolio-based conversations revealed that 20% of the segments were made up of reflection (content reflection…

Scales and scaling in turbulent ocean sciences; physics-biology coupling

Science.gov (United States)

Schmitt, Francois

2015-04-01

Geophysical fields possess huge fluctuations over many spatial and temporal scales. In the ocean, such property at smaller scales is closely linked to marine turbulence. The velocity field is varying from large scales to the Kolmogorov scale (mm) and scalar fields from large scales to the Batchelor scale, which is often much smaller. As a consequence, it is not always simple to determine at which scale a process should be considered. The scale question is hence fundamental in marine sciences, especially when dealing with physics-biology coupling. For example, marine dynamical models have typically a grid size of hundred meters or more, which is more than 105 times larger than the smallest turbulence scales (Kolmogorov scale). Such scale is fine for the dynamics of a whale (around 100 m) but for a fish larvae (1 cm) or a copepod (1 mm) a description at smaller scales is needed, due to the nonlinear nature of turbulence. The same is verified also for biogeochemical fields such as passive and actives tracers (oxygen, fluorescence, nutrients, pH, turbidity, temperature, salinity...) In this framework, we will discuss the scale problem in turbulence modeling in the ocean, and the relation of Kolmogorov's and Batchelor's scales of turbulence in the ocean, with the size of marine animals. We will also consider scaling laws for organism-particle Reynolds numbers (from whales to bacteria), and possible scaling laws for organism's accelerations.

ePortfolio & learning styles in Nursing Education

DEFF Research Database (Denmark)

Nielsen, Kirsten; Helms, Niels Henrik; Pedersen, Birthe D.

2012-01-01

Background Examination of the literature shows both advantages and disadvantages in implementing ePortfolio and learning styles in Nursing Education. The students reflect on nursing practice as well as on their strengths and weaknesses, and reflecting in the portfolio increases self-awareness, pe......Background Examination of the literature shows both advantages and disadvantages in implementing ePortfolio and learning styles in Nursing Education. The students reflect on nursing practice as well as on their strengths and weaknesses, and reflecting in the portfolio increases self...... in clinical settings. Insight into preferred learning style can be an advantage to both students and preceptors in attempt to promote students´ learning potential, but there are quite many different theoretical approaches and definitions of the concept, and reviewers call attention to the risk that teachers...... to intensify the differentiated guidance of students, and developed an ePortfolio which aim to facilitate four learning styles as described by Honey and Mumford. It was tested in a pilot project and now, a qualitative study of how learning is mediated in clinical education through this ePortfolio is passing...

Beating the market with small portfolios: Evidence from Brazil

Directory of Open Access Journals (Sweden)

André A.P. Santos

2015-01-01

Full Text Available Optimal portfolios with a restriction on the number of assets, also referred to as cardinality-constrained portfolios, have been receiving attention in the literature due to its popularity among market practitioners and retail investors. In most cases, however, the interest is in proposing efficient optimization methods to solve the problem, with little or no attention to the characteristics of the resulting portfolio such as risk-adjusted performance and turnover. We address this question by implementing a tractable reformulation of the cardinality-constrained version of the minimum variance portfolio. We analyze the out-of-sample performance of cardinality-constrained portfolios according to alternative criteria and check the robustness of the results for portfolios with alternative number of assets and under alternative re-balancing frequencies. Our empirical application for the Brazilian equities market shows that cardinality-constrained minimum variance portfolios with very few assets, e.g. 3 stocks, can deliver statistically lower portfolio risk and higher Sharpe ratios in comparison to the market index. Similar results are obtained for constrained portfolios with 5 and 10 assets and under daily, weekly, and monthly re-balancing frequencies. Our evidence indicates that it is possible to obtain better risk-adjusted performance with fewer securities in the portfolio by using an improved allocation scheme.

Construction of uncertainty sets for portfolio selection problems

OpenAIRE

Wiechers, Christof

2011-01-01

While modern portfolio theory grounds on the trade-off between portfolio return and portfolio variance to determine the optimal investment decision, postmodern portfolio theory uses downside risk measures instead of the variance. Prominent examples are given by the risk measures Value-at-Risk and its coherent extension, Conditional Value-at-Risk. When avoiding distributional assumptions on the process that generates the risky assets' returns, historical return data or expert knowledge remain ...

Formal Method of Description Supporting Portfolio Assessment

Science.gov (United States)

Morimoto, Yasuhiko; Ueno, Maomi; Kikukawa, Isao; Yokoyama, Setsuo; Miyadera, Youzou

2006-01-01

Teachers need to assess learner portfolios in the field of education. However, they need support in the process of designing and practicing what kind of portfolios are to be assessed. To solve the problem, a formal method of describing the relations between the lesson forms and portfolios that need to be collected and the relations between…

7 CFR 4290.760 - How a change in size or activity of a Portfolio Concern affects the RBIC and the Portfolio Concern.

Science.gov (United States)

2010-01-01

... 7 Agriculture 15 2010-01-01 2010-01-01 false How a change in size or activity of a Portfolio Concern affects the RBIC and the Portfolio Concern. 4290.760 Section 4290.760 Agriculture Regulations of... size or activity of a Portfolio Concern affects the RBIC and the Portfolio Concern. (a) Effect on RBIC...

Making practice transparent through e-portfolio.

Science.gov (United States)

Stewart, Sarah M

2013-12-01

Midwives are required to maintain a professional portfolio as part of their statutory requirements. Some midwives are using open social networking tools and processes to develop an e-portfolio. However, confidentiality of patient and client data and professional reputation have to be taken into consideration when using online public spaces for reflection. There is little evidence about how midwives use social networking tools for ongoing learning. It is uncertain how reflecting in an e-portfolio with an audience impacts on learning outcomes. This paper investigates ways in which reflective midwifery practice be carried out using e-portfolio in open, social networking platforms using collaborative processes. Using an auto-ethnographic approach I explored my e-portfolio and selected posts that had attracted six or more comments. I used thematic analysis to identify themes within the textual conversations in the posts and responses posted by readers. The analysis identified that my collaborative e-portfolio had four themes: to provide commentary and discuss issues; to reflect and process learning; to seek advice, brainstorm and process ideas for practice, projects and research, and provide evidence of professional development. E-portfolio using open social networking tools and processes is a viable option for midwives because it facilitates collaborative reflection and shared learning. However, my experience shows that concerns about what people think, and client confidentiality does impact on the nature of open reflection and learning outcomes. I conclude this paper with a framework for managing midwifery statutory obligations using online public spaces and social networking tools. Copyright © 2013 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

Analysis of the energy portfolio for electricity generation

International Nuclear Information System (INIS)

Ramirez S, J. R.; Alonso V, G.; Esquivel E, J.

2016-09-01

The planning of electricity generation systems considers several factors that must be taken into account in order to design systems that are economical, reliable and sustainable. For this purpose, the Financial Portfolio Theory is applicable to the energy portfolio or the diversification of electricity generation technologies, such as is the combined cycle, wind, thermoelectric and nuclear. This paper presents an application of the Portfolio Theory to the national energy system, based on the total generation costs for each technology, which allows determining the average variance portfolio and the respective share of each of the electricity generation technologies considered, obtaining a portfolio of electricity generation with the maximum possible return for the risk taken in the investments. This paper describes the basic aspects of the Portfolio Theory and its methodology, in which matrices are implemented for the solution of the resulting Lagrange system. (Author)

Meta-analysis reveals complex marine biological responses to the interactive effects of ocean acidification and warming

Science.gov (United States)

Harvey, Ben P; Gwynn-Jones, Dylan; Moore, Pippa J

2013-01-01

Ocean acidification and warming are considered two of the greatest threats to marine biodiversity, yet the combined effect of these stressors on marine organisms remains largely unclear. Using a meta-analytical approach, we assessed the biological responses of marine organisms to the effects of ocean acidification and warming in isolation and combination. As expected biological responses varied across taxonomic groups, life-history stages, and trophic levels, but importantly, combining stressors generally exhibited a stronger biological (either positive or negative) effect. Using a subset of orthogonal studies, we show that four of five of the biological responses measured (calcification, photosynthesis, reproduction, and survival, but not growth) interacted synergistically when warming and acidification were combined. The observed synergisms between interacting stressors suggest that care must be made in making inferences from single-stressor studies. Our findings clearly have implications for the development of adaptive management strategies particularly given that the frequency of stressors interacting in marine systems will be likely to intensify in the future. There is now an urgent need to move toward more robust, holistic, and ecologically realistic climate change experiments that incorporate interactions. Without them accurate predictions about the likely deleterious impacts to marine biodiversity and ecosystem functioning over the next century will not be possible. PMID:23610641

Tumor Biology and Microenvironment Research

Science.gov (United States)

Part of NCI's Division of Cancer Biology's research portfolio, research in this area seeks to understand the role of tumor cells and the tumor microenvironment (TME) in driving cancer initiation, progression, maintenance and recurrence.

Structural Biology and Molecular Applications Research

Science.gov (United States)

Part of NCI's Division of Cancer Biology's research portfolio, research and development in this area focuses on enabling technologies, models, and methodologies to support basic and applied cancer research.

Portfolio Assessment: A Handbook for Educators. Assessment Bookshelf Series.

Science.gov (United States)

Barton, James, Ed.; Collins, Angelo, Ed.

This guide contains practical steps for integrating portfolios into any K-12 classroom and tips for effective classroom management of portfolios. It also contains actual examples of portfolios in action in a variety of subject areas. The chapters are: (1) "Starting Out: Designing Your Portfolio" (James Barton and Angelo Collins); (2) "Preparing…

Professionalism, Portfolios and the Development of School Leaders.

Science.gov (United States)

Wildy, Helen; Wallace, John

1998-01-01

Describes how two reforms--portfolio culture and teacher professionalism--converge in a systemwide program for school leaders' professional development. Investigates use of portfolios to help (Australian) principals, deputy principals, and department heads improve their performance and accountability. Participants used portfolios as evidence of…

Selection of a portfolio of R & D projects

NARCIS (Netherlands)

Casault, Sébastien; Groen, Arend J.; Linton, J.D.; Linton, Jonathan; Link, A.N.; Vonortas, N.S.

2013-01-01

While portfolios of research are increasingly discussed, a portfolio perspective is infrequently taken when selecting two or more projects. Consequently, this chapter considers the current state of knowledge in project and portfolio selection, identifies why we can and cannot apply knowledge from

ALPHA-BETA SEPARATION PORTFOLIO STRATEGIES FOR ISLAMIC FINANCE

OpenAIRE

Valentyn Khokhlov

2016-01-01

The purpose of this paper is to develop a mathematical alpha-beta separation model that can be used to create a core-satellite portfolio management strategy that complies with the principles of Islamic finance. Methodology. Core-satellite portfolio construction methodology is used to implement the alpha-beta separation approach, where the core part of the portfolio is managed using the tracking error minimization strategy, and the satellite part of the portfolio is managed using the mean-vari...

Deformed exponentials and portfolio selection

Science.gov (United States)

Rodrigues, Ana Flávia P.; Guerreiro, Igor M.; Cavalcante, Charles Casimiro

In this paper, we present a method for portfolio selection based on the consideration on deformed exponentials in order to generalize the methods based on the gaussianity of the returns in portfolio, such as the Markowitz model. The proposed method generalizes the idea of optimizing mean-variance and mean-divergence models and allows a more accurate behavior for situations where heavy-tails distributions are necessary to describe the returns in a given time instant, such as those observed in economic crises. Numerical results show the proposed method outperforms the Markowitz portfolio for the cumulated returns with a good convergence rate of the weights for the assets which are searched by means of a natural gradient algorithm.

Optimal diversification of the securities portfolio

Directory of Open Access Journals (Sweden)

Валентина Михайловна Андриенко

2016-09-01

Full Text Available The article deals with problems of the theory and methods of forming the optimal portfolio of financial markets. The analytical review of methods in their historical development is given. Recommendations on the use of a particular method depends on the specific conditions are formulated. The classical and alternative methods are considered. The main attention is paid to the analysis of the investment portfolio of derivative securities in B/S-market modelThe article deals with problems of the theory and methods of forming the optimal portfolio of financial markets. The analytical review of methods in their historical development is given. Recommendations on the use of a particular method depends on the specific conditions are formulated. The classical and alternative methods are considered. The main attention is paid to the analysis of the investment portfolio of derivative securities in -market model

Complementary constraints from carbon (13C) and nitrogen (15N) isotopes on the glacial ocean's soft-tissue biological pump

Science.gov (United States)

Schmittner, A.; Somes, C. J.

2016-06-01

A three-dimensional, process-based model of the ocean's carbon and nitrogen cycles, including 13C and 15N isotopes, is used to explore effects of idealized changes in the soft-tissue biological pump. Results are presented from one preindustrial control run (piCtrl) and six simulations of the Last Glacial Maximum (LGM) with increasing values of the spatially constant maximum phytoplankton growth rate μmax, which accelerates biological nutrient utilization mimicking iron fertilization. The default LGM simulation, without increasing μmax and with a shallower and weaker Atlantic Meridional Overturning Circulation and increased sea ice cover, leads to 280 Pg more respired organic carbon (Corg) storage in the deep ocean with respect to piCtrl. Dissolved oxygen concentrations in the colder glacial thermocline increase, which reduces water column denitrification and, with delay, nitrogen fixation, thus increasing the ocean's fixed nitrogen inventory and decreasing δ15NNO3 almost everywhere. This simulation already fits sediment reconstructions of carbon and nitrogen isotopes relatively well, but it overestimates deep ocean δ13CDIC and underestimates δ15NNO3 at high latitudes. Increasing μmax enhances Corg and lowers deep ocean δ13CDIC, improving the agreement with sediment data. In the model's Antarctic and North Pacific Oceans modest increases in μmax result in higher δ15NNO3 due to enhanced local nutrient utilization, improving the agreement with reconstructions there. Models with moderately increased μmax fit both isotope data best, whereas large increases in nutrient utilization are inconsistent with nitrogen isotopes although they still fit the carbon isotopes reasonably well. The best fitting models reproduce major features of the glacial δ13CDIC, δ15N, and oxygen reconstructions while simulating increased Corg by 510-670 Pg compared with the preindustrial ocean. These results are consistent with the idea that the soft-tissue pump was more efficient

Technology Audit: Assessment of Innovative Portfolio

Directory of Open Access Journals (Sweden)

Kurushina Viktoria

2016-01-01

Full Text Available The article discusses the features of the technological audit performing in the companies of oil and gas sector of Russian economy. To measure the innovations quality level the scale was developed based on the Theory of Inventive Problem Solving and the theory of technological structures. Figures of the innovations quantity by levels, volume and quality of the innovative portfolio are offered for assessment the innovative portfolio quality. The method was tested on an example of oil and gas transporting enterprises. The results of the comparative analysis of innovative portfolio are shown.

Validity of portfolio assessment: which qualities determine ratings?

NARCIS (Netherlands)

Driessen, E.W.; Overeem, K.; Tartwijk, J. van; Vleuten, C.P.M. van der; Muijtjens, A.M.M.

2006-01-01

The portfolio is becoming increasingly accepted as a valuable tool for learning and assessment. The validity of portfolio assessment, however, may suffer from bias due to irrelevant qualities, such as lay-out and writing style. We examined the possible effects of such qualities in a portfolio

Physical and biological data collected with a towed vehicle to support studies in the Southern Oceans, January - February 1998 (NODC Accession 0000947)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Physical and biological data were collected using fluorometer and CTD casts from the ROGER REVELLE in the Southern Oceans from 12 January 1998 to 03 February 1998....

Portfolio at Tertiary Level – Lifelong Learning Tool

Directory of Open Access Journals (Sweden)

Galina Kavaliauskienė

2011-04-01

Full Text Available The use of electronic language portfolios has been preferable to the use of common paper portfolios for ease of application – there is no need for accumulating a number of files of written papers, which solves the problem of storing space and, to some extent, helps reduce students’ and teachers’ workload.The study investigated learners’ perceptions of employing electronic language portfolios for conducting various assignments in English for Specific Purposes. The research involved university students of different specializations. Learners’ experience of employing portfolios and opinions on their benefits for improving language skills have been analyzed and statistically treated using SPSS software. The results show that students are positive about application of electronic portfolios in ESP classes. The use of online portfolios for various assignments helps teachers foster students’ learning, encourages critical thinking, develops creativity, motivates learners to use digital technology, encourages collaboration of learners, and in the long run, leads to lifelong learning.

Portfolios in Saudi medical colleges. Why and how?

Directory of Open Access Journals (Sweden)

Nadia M. Fida

2016-03-01

Full Text Available Over recent decades, the use of portfolios in medical education has evolved, and is being applied in undergraduate and postgraduate programs worldwide. Portfolios, as a learning process and method of documenting and assessing learning, is supported as a valuable tool by adult learning theories that stress the need for learners to be self-directed and to engage in experiential learning. Thoughtfully implemented, a portfolio provides learning experiences unequaled by any single learning tool. The credibility (validity and dependability (reliability of assessment through portfolios have been questioned owing to its subjective nature; however, methods to safeguard these features have been described in the literature. This paper discusses some of this literature, with particular attention to the role of portfolios in relation to self-reflective learning, provides an overview of current use of portfolios in undergraduate medical education in Saudi Arabia, and proposes research-based guidelines for its implementation and other similar contexts.

The Shapley decomposition for portfolio risk

OpenAIRE

Stéphane Mussard; Virginie Terraza

2006-01-01

The aim of this paper is to provide an application of the Shapley Value to decompose financial portfolio risk. Decomposing the sample covariance risk measure yields relative measures, which enable securities of a portfolio to be classified according to risk scales.

Automatic Trading Agent. RMT Based Portfolio Theory and Portfolio Selection

Science.gov (United States)

Snarska, M.; Krzych, J.

2006-11-01

Portfolio theory is a very powerful tool in the modern investment theory. It is helpful in estimating risk of an investor's portfolio, arosen from lack of information, uncertainty and incomplete knowledge of reality, which forbids a perfect prediction of future price changes. Despite of many advantages this tool is not known and not widely used among investors on Warsaw Stock Exchange. The main reason for abandoning this method is a high level of complexity and immense calculations. The aim of this paper is to introduce an automatic decision-making system, which allows a single investor to use complex methods of Modern Portfolio Theory (MPT). The key tool in MPT is an analysis of an empirical covariance matrix. This matrix, obtained from historical data, biased by such a high amount of statistical uncertainty, that it can be seen as random. By bringing into practice the ideas of Random Matrix Theory (RMT), the noise is removed or significantly reduced, so the future risk and return are better estimated and controlled. These concepts are applied to the Warsaw Stock Exchange Simulator {http://gra.onet.pl}. The result of the simulation is 18% level of gains in comparison with respective 10% loss of the Warsaw Stock Exchange main index WIG.

Comparative Analysis of Investment Funds Stocks-based Portfolios and BET Stocks-based Portfolios

Directory of Open Access Journals (Sweden)

Ion STANCU

2010-04-01

Full Text Available In this paper we intend to find out what is the best choice of stocks-based portfolio. The major goal is to find whether is more efficient to invest the whole capital in a single sector, like financial investments, or to create a diversified portfolio, taking into account assets from various economic sectors. Capital allocation will be based on the concept of cointegration. We have chosen this method because it can be applied on non-stationary data series, and, besides, it has the advantage of using the whole set of information provided by the financial assets. Another goal is to study how the portfolio structure adjusts if a shock occurs during the period under analysis so that to preserve a certain return or minimize a potential loss. The study will result in an investment solution in the Romanian capital market, even in the context of financial crisis.

Portfolio Development in Teacher Education and Educational Leadership.

Science.gov (United States)

Biddle, James

The Ohio Consortium for Portfolio Development was established in 1988 as an interinstitutional research effort to integrate portfolio development into teacher education. A subphase focused on portfolio use by entry year teachers in a metropolitan school system. Personnel at Wright State University, Central State University, and the University of…

The true invariant of an arbitrage free portfolio

Science.gov (United States)

Schmidt, Anatoly B.

2003-03-01

It is shown that the arbitrage free portfolio paradigm being applied to a portfolio with an arbitrary number of shares N allows for the extended solution in which the option price F depends on N. However the resulting stock hedging expense Q= MF (where M is the number of options in the portfolio) does not depend on whether N is treated as an independent variable or as a parameter. Therefore the stock hedging expense is the true invariant of the arbitrage free portfolio paradigm.

Investment portfolio management from cybernetic point of view

Science.gov (United States)

Marchev, Angel, Jr.; Marchev, Angel

2013-12-01

The theory of investment portfolios is a well defined component of financial science. While sound in principle, it faces some setbacks in its real-world implementation. In this paper the authors propose a reformulation of the investment portfolio problem as a cybernetic system where the Investor is the controlling system and the portfolio is the controlled system. Also the portfolio controlling process should be dissected in several ordered phases, so that each phase is represented as a subsystem within the structure of the controlling system Investor.

EPOCA/EUR-OCEANS data compilation on the biological and biogeochemical responses to ocean acidification

NARCIS (Netherlands)

Nisumaa, A.-M.; Pesant, S.; Bellerby, R.G.J.; Delille, B.; Middelburg, J.J.; Orr, J.C.; Riebesell, U.; Tyrrell, T.; Wolf-Gladrow, D.; Gattuso, J.P.

2010-01-01

The uptake of anthropogenic CO2 by the oceans has led to a rise in the oceanic partial pressure of CO2, and to a decrease in pH and carbonate ion concentration. This modification of the marine carbonate system is referred to as ocean acidification. Numerous papers report the effects of ocean

An updated synthesis of the observed and projected impacts of climate change on the chemical, physical and biological processes in the oceans

Directory of Open Access Journals (Sweden)

Ella Louise Howes

2015-06-01

Full Text Available The 5th Assessment Report (AR5 of the Intergovernmental Panel on Climate Change (IPCC states with very high certainty that anthropogenic emissions have caused measurable changes in the physical ocean environment. These changes are summarized with special focus on those that are predicted to have the strongest, most direct effects on ocean biological processes; namely, ocean warming and associated phenomena (including stratification and sea level rise as well as deoxygenation and ocean acidification. The biological effects of these changes are then discussed for microbes (including phytoplankton, plants, animals, warm and cold-water corals, and ecosystems. The IPCC AR5 highlighted several areas related to both the physical and biological processes that required further research. As a rapidly developing field, there have been many pertinent studies published since the cut off dates for the AR5, which have increased our understanding of the processes at work. This study undertook an extensive review of recently published literature to update the findings of the AR5 and provide a synthesized review on the main issues facing future oceans. The level of detail provided in the AR5 and subsequent work provided a basis for constructing projections of the state of ocean ecosystems in 2100 under two the Representative Concentration Pathways RCP4.5 and 8.5. Finally the review highlights notable additions, clarifications and points of departure from AR5 provided by subsequent studies.

Stirring Up the Biological Pump: Vertical Mixing and Carbon Export in the Southern Ocean

Science.gov (United States)

Stukel, Michael R.; Ducklow, Hugh W.

2017-09-01

The biological carbon pump (BCP) transports organic carbon from the surface to the ocean's interior via sinking particles, vertically migrating organisms, and passive transport of organic matter by advection and diffusion. While many studies have quantified sinking particles, the magnitude of passive transport remains poorly constrained. In the Southern Ocean weak thermal stratification, strong vertical gradients in particulate organic matter, and weak vertical nitrate gradients suggest that passive transport from the euphotic zone may be particularly important. We compile data from seasonal time series at a coastal site near Palmer Station, annual regional cruises in the Western Antarctic Peninsula (WAP), cruises throughout the broader Southern Ocean, and SOCCOM (Southern Ocean Carbon and Climate Observations and Modeling) autonomous profiling floats to estimate spatial and temporal patterns in vertical gradients of nitrate, particulate nitrogen (PN), and dissolved organic carbon. Under a steady state approximation, the ratio of ∂PN/∂z to ∂NO3-/∂z suggests that passive transport of PN may be responsible for removing 46% (37%-58%) of the nitrate introduced into the surface ocean of the WAP (with dissolved organic matter contributing an additional 3-6%) and for 23% (19%-28%) of the BCP in the broader Southern Ocean. A simple model parameterized with in situ nitrate, PN, and primary production data suggested that passive transport was responsible for 54% of the magnitude of the BCP in the WAP. Our results highlight the potential importance of passive transport (by advection and diffusion) of organic matter in the Southern Ocean but should only be considered indicative of high passive transport (rather than conclusive evidence) due to our steady state assumptions.

E-PORTFOLIO: BEYOND ASSESSMENT FOR ENGLISH STUDENT TEACHER (a Preliminary Study of E-portfolio Implementation in Micro Teaching Class)

OpenAIRE

Sarlita D. Matra

2017-01-01

Teacher preparation programs across the country are showing an increased interest in the use of electronic portfolios as valuable authentic assessment tools that can document students‘ abilities and growth related to specific standards. The concept of developing e-portfolios is based on the fact that the reflective practice of creating portfolios enables students to document and track their learning; develop an integrated, coherent picture of their learning experiences; and enhanc...

Implementing portfolio in postgraduate general practice training. Benefits and recommendations.

Science.gov (United States)

Alotaibi, Fawaz S

2012-10-01

This paper presents a review to explore the literature focusing on portfolio in postgraduate general practice (GP) training, and to examine the impact of implementation of portfolio on learning process, as well as proposing recommendations for its implementation in postgraduate GP training. An electronic search was carried out on several databases for studies addressing portfolio in postgraduate GP training. Six articles were included to address specifically the effectiveness of portfolio in postgraduate GP training. Five of them described successful experiences of portfolio-based learning implementation. Only one article addressed portfolio-based assessment in postgraduate GP training. The existing evidence provides various benefits of professional portfolio-based learning. It does appear to have advantages of stimulating reflective learning, promoting proactive learning, and bridging the hospital experiences of the learners to GP. Moreover, the challenges to implementation of portfolio-based learning are often based on orientation and training of stakeholders.

Asset Allocation and Optimal Contract for Delegated Portfolio Management

Science.gov (United States)

Liu, Jingjun; Liang, Jianfeng

This article studies the portfolio selection and the contracting problems between an individual investor and a professional portfolio manager in a discrete-time principal-agent framework. Portfolio selection and optimal contracts are obtained in closed form. The optimal contract was composed with the fixed fee, the cost, and the fraction of excess expected return. The optimal portfolio is similar to the classical two-fund separation theorem.

On the microeconomic problems studied by portfolio theory

Science.gov (United States)

Nikonov, Oleg; Medvedeva, Marina

2012-09-01

In the paper we consider economically motivated problems, which are treated with the help of methods of portfolio theory that goes back to the papers by H. Markowitz [1] and J. Tobin [2]. We show that the portfolio theory initially developed for risky securities (stocks) could be applied to other objects. In the present paper we consider several situations where such an application is reasonable and seems to be fruitful. Namely, we consider the problems of constructing the efficient portfolio of banking services and the portfolio of counteragents of a firm.

Students' reflections in a portfolio pilot: highlighting professional issues.

Science.gov (United States)

Haffling, Ann-Christin; Beckman, Anders; Pahlmblad, Annika; Edgren, Gudrun

2010-01-01

Portfolios are highlighted as potential assessment tools for professional competence. Although students' self-reflections are considered to be central in the portfolio, the content of reflections in practice-based portfolios is seldom analysed. To investigate whether students' reflections include sufficient dimensions of professional competence, notwithstanding a standardized portfolio format, and to evaluate students' satisfaction with the portfolio. Thirty-five voluntary final-year medical students piloted a standardized portfolio in a general practice (GP) attachment at Lund University, Sweden. Students' portfolio reflections were based upon documentary evidence from practice, and aimed to demonstrate students' learning. The reflections were qualitatively analysed, using a framework approach. Students' evaluations of the portfolio were subjected to quantitative and qualitative analysis. Among professional issues, an integration of cognitive, affective and practical dimensions in clinical practice was provided by students' reflections. The findings suggested an emphasis on affective issues, particularly on self-awareness of feelings, attitudes and concerns. In addition, ethical problems, clinical reasoning strategies and future communication skills training were subjects of several reflective commentaries. Students' reflections on their consultation skills demonstrated their endeavour to achieve structure in the medical interview by negotiation of an agenda for the consultation, keeping the interview on track, and using internal summarizing. The importance of active listening and exploration of patient's perspective was also emphasized. In students' case summaries, illustrating characteristic attributes of GP, the dominating theme was 'patient-centred care', including the patient-doctor relationship, holistic modelling and longitudinal continuity. Students were satisfied with the portfolio, but improved instructions were needed. A standardized portfolio in a

Portfolios with nonlinear constraints and spin glasses

Science.gov (United States)

Gábor, Adrienn; Kondor, I.

1999-12-01

In a recent paper Galluccio, Bouchaud and Potters demonstrated that a certain portfolio problem with a nonlinear constraint maps exactly onto finding the ground states of a long-range spin glass, with the concomitant nonuniqueness and instability of the optimal portfolios. Here we put forward geometric arguments that lead to qualitatively similar conclusions, without recourse to the methods of spin glass theory, and give two more examples of portfolio problems with convex nonlinear constraints.

R functions development for stockPortfolio package

OpenAIRE

Luo, Rui

2013-01-01

Modern portfolio theory is a statistical framework to allocate investment assets properly, with the aim of reducing risk by diversification. In the past decades, a variety of index and group models (with different covariance assumption) have been proposed to optimize the portfolio, including Single Index Model, Constant Correlation Model, Multi-Group Model, and Multi-Index Model. An R package "stockPortfolio" is developed by Drs. Christou and Diez, and fully implemented Single Index Model, Co...

Optimal portfolio choice under loss aversion

NARCIS (Netherlands)

A.B. Berkelaar (Arjan); R.R.P. Kouwenberg (Roy)

2000-01-01

textabstractProspect theory and loss aversion play a dominant role in behavioral finance. In this paper we derive closed-form solutions for optimal portfolio choice under loss aversion. When confronted with gains a loss averse investor behaves similar to a portfolio insurer. When confronted with

Random matrix theory filters and currency portfolio optimisation

Science.gov (United States)

Daly, J.; Crane, M.; Ruskin, H. J.

2010-04-01

Random matrix theory (RMT) filters have recently been shown to improve the optimisation of financial portfolios. This paper studies the effect of three RMT filters on realised portfolio risk, using bootstrap analysis and out-of-sample testing. We considered the case of a foreign exchange and commodity portfolio, weighted towards foreign exchange, and consisting of 39 assets. This was intended to test the limits of RMT filtering, which is more obviously applicable to portfolios with larger numbers of assets. We considered both equally and exponentially weighted covariance matrices, and observed that, despite the small number of assets involved, RMT filters reduced risk in a way that was consistent with a much larger S&P 500 portfolio. The exponential weightings indicated showed good consistency with the value suggested by Riskmetrics, in contrast to previous results involving stocks. This decay factor, along with the low number of past moves preferred in the filtered, equally weighted case, displayed a trend towards models which were reactive to recent market changes. On testing portfolios with fewer assets, RMT filtering provided less or no overall risk reduction. In particular, no long term out-of-sample risk reduction was observed for a portfolio consisting of 15 major currencies and commodities.

RISK MANAGEMENT OF INVESTMENT PORTFOLIO BY FUTURE

Directory of Open Access Journals (Sweden)

K. Kerimov Alexandr

2017-01-01

Full Text Available The article considers the problem of the dynamic risk management of the investment portfolio using future con- tracts. The management starts with the concept of effective inhomogeneous portfolios, which contain futures together with underlying asserts. The effective portfolios are defined as the ones of the minimal dispersion with the expected return greater or equal to the specified value. Risk is measured by the probability of losing of a certain part of the portfolio value. The control parameters are the number of futures for each asset of portfolio, which is defined from the condition of effec- tiveness of portfolio and risk acceptability on each step.The effective adaptive strategies of portfolio risk management together with comparative analysis on a concrete example are presented. The proposed approach provides the forecast correction of the expected income and its variance for the assets with the emergence of new data. The financial time series are determined by volatility clustering, i.e. relative or absolute price changes tend to keep high or low magnitude for some time, with the result that clusters are created - periods of high or low volatility. Then adaptive estimate of correlational relationships between asset prices are essential because the degree of correlational relationship also changes in time. So the correlation of future and spot price changes considerably increases while approaching to performance of contracts. For taking into account of data instability of dispersion and correlation simple methods of volatility forecasting and correlation of relative changes of price data based on exponential smoothing are implemented.

Portfolio analysis of layered security measures.

Science.gov (United States)

Chatterjee, Samrat; Hora, Stephen C; Rosoff, Heather

2015-03-01

Layered defenses are necessary for protecting the public from terrorist attacks. Designing a system of such defensive measures requires consideration of the interaction of these countermeasures. In this article, we present an analysis of a layered security system within the lower Manhattan area. It shows how portfolios of security measures can be evaluated through portfolio decision analysis. Consideration is given to the total benefits and costs of the system. Portfolio diagrams are created that help communicate alternatives among stakeholders who have differing views on the tradeoffs between security and economic activity. © 2014 Society for Risk Analysis.

Does asymmetric correlation affect portfolio optimization?

Science.gov (United States)

Fryd, Lukas

2017-07-01

The classical portfolio optimization problem does not assume asymmetric behavior of relationship among asset returns. The existence of asymmetric response in correlation on the bad news could be important information in portfolio optimization. The paper applies Dynamic conditional correlation model (DCC) and his asymmetric version (ADCC) to propose asymmetric behavior of conditional correlation. We analyse asymmetric correlation among S&P index, bonds index and spot gold price before mortgage crisis in 2008. We evaluate forecast ability of the models during and after mortgage crisis and demonstrate the impact of asymmetric correlation on the reduction of portfolio variance.

On the economic risk capital of portfolio insurance

Directory of Open Access Journals (Sweden)

Werner Hürlimann

2004-09-01

Full Text Available A formula for the conditional value-at-risk of classical portfolio insurance is derived and shown to be constant for sufficiently small loss probabilities. As illustrations, we discuss portfolio insurance for an equity market index using empirical data, and analyze the more general multivariate situation of a portfolio of risky assets.

The electricity portfolio simulation model (EPSim) technical description.

Energy Technology Data Exchange (ETDEWEB)

Drennen, Thomas E.; Klotz, Richard (Hobart and William Smith Colleges, Geneva, NY)

2005-09-01

Stakeholders often have competing interests when selecting or planning new power plants. The purpose of developing this preliminary Electricity Portfolio Simulation Model (EPSim) is to provide a first cut, dynamic methodology and approach to this problem, that can subsequently be refined and validated, that may help energy planners, policy makers, and energy students better understand the tradeoffs associated with competing electricity portfolios. EPSim allows the user to explore competing electricity portfolios annually from 2002 to 2025 in terms of five different criteria: cost, environmental impacts, energy dependence, health and safety, and sustainability. Four additional criteria (infrastructure vulnerability, service limitations, policy needs and science and technology needs) may be added in future versions of the model. Using an analytic hierarchy process (AHP) approach, users or groups of users apply weights to each of the criteria. The default energy assumptions of the model mimic Department of Energy's (DOE) electricity portfolio to 2025 (EIA, 2005). At any time, the user can compare alternative portfolios to this reference case portfolio.

Portfolios for Majors in Professional Communication.

Science.gov (United States)

Killingsworth, M. Jimmie; Sanders, Scott P.

1987-01-01

Suggests general principles for developing assignments where students prepare portfolios that reveal their overall communication skills in addition to the usual job search tools. Emphasizes that students should concentrate on including works in the portfolio with the criteria of quality, variety, professionalism, and maturity in mind. (SKC)

Portfolio Diversification Effects of Downside Risk

NARCIS (Netherlands)

N. Hyung (Namwon); C.G. de Vries (Casper)

2004-01-01

textabstractRisk managers use portfolios to diversify away the un-priced risk of individual securities. In this paper we compare the benefits of portfolio diversification for downside risk in case returns are normally distributed with the case fat tailed distributed returns. The downside risk of a

Credit Portfolio Selection According to Sectors in Risky Environments: Markowitz Practice

OpenAIRE

Halim Kazan; Kültigin Uludag

2014-01-01

In this study, it was researched that how the rate of repayment of loans will be increased and how the credit risk will be minimized in banking sector, by using Markowitz Portfolio Theory. Construction, textile and wholesale and retail sectors were examined under the central bank data. Portfolio groups were selected and risks( variances of Portfolio groups) were evaluated according to Markowitz portfolio theory. Markowitz portfolio theory is effective than the other portfolio selection instru...

Optimal wind power deployment in Europe. A portfolio approach

International Nuclear Information System (INIS)

Roques, Fabien; Hiroux, Celine; Saguan, Marcelo

2010-01-01

Geographic diversification of wind farms can smooth out the fluctuations in wind power generation and reduce the associated system balancing and reliability costs. The paper uses historical wind production data from five European countries (Austria, Denmark, France, Germany, and Spain) and applies the Mean-Variance Portfolio theory to identify cross-country portfolios that minimise the total variance of wind production for a given level of production. Theoretical unconstrained portfolios show that countries (Spain and Denmark) with the best wind resource or whose size contributes to smoothing out the country output variability dominate optimal portfolios. The methodology is then elaborated to derive optimal constrained portfolios taking into account national wind resource potential and transmission constraints and compare them with the projected portfolios for 2020. Such constraints limit the theoretical potential efficiency gains from geographical diversification, but there is still considerable room to improve performance from actual or projected portfolios. These results highlight the need for more cross-border interconnection capacity, for greater coordination of European renewable support policies, and for renewable support mechanisms and electricity market designs providing locational incentives. Under these conditions, a mechanism for renewables credits trading could help aligning wind power portfolios with the theoretically efficient geographic dispersion. (author)

Power from Perspective: Potential future United States energy portfolios

International Nuclear Information System (INIS)

Tonn, Bruce; Healy, K.C.; Gibson, Amy; Ashish, Ashutosh; Cody, Preston; Beres, Drew; Lulla, Sam; Mazur, Jim; Ritter, A.J.

2009-01-01

This paper presents United States energy portfolios for the year 2030, developed from seven different Perspectives. The Perspectives are characterized by different weights placed on fourteen defining values (e.g., cost, social acceptance). The portfolios were constructed to achieve three primary goals, energy independence, energy security, and greenhouse gas reductions. The portfolios are also evaluated over a comprehensive set of secondary criteria (e.g., economic growth, technical feasibility). It is found that very different portfolios based on very different defining values can achieve the three primary goals. Commonalities among the portfolios include reliance upon cellulosic ethanol, nuclear power, and energy efficiency to meet year 2030 energy demands. It is concluded that the US energy portfolio must be diverse and to achieve national energy goals will require an explicit statement of goals, a strong role for government, and coordinated action across society

Ocean Uses: California

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This Ocean Uses Atlas Project is an innovative partnership between NOAA's National Marine Protected Areas Center and Marine Conservation Biology Institute. The...

On the Teaching of Portfolio Theory.

Science.gov (United States)

Biederman, Daniel K.

1992-01-01

Demonstrates how a simple portfolio problem expressed explicitly as an expected utility maximization problem can be used to instruct students in portfolio theory. Discusses risk aversion, decision making under uncertainty, and the limitations of the traditional mean variance approach. Suggests students may develop a greater appreciation of general…

Low volatility sector-based portfolios: a South African case

African Journals Online (AJOL)

Black pointed out that when investors are restricted from using leverage or bor- ..... takes into account the correlation between the sectors in a portfolio. ..... 3The information ratio of a portfolio is the active premium (portfolio annualised return ...

Portfolio Diversification with Commodity Futures: Properties of Levered Futures

NARCIS (Netherlands)

Woodard, J.D.; Egelkraut, T.M.; Garcia, P.; Pennings, J.M.E.

2005-01-01

Portfolio Diversification with Commodity Futures: Properties of Levered Futures This study extends previous work on the impact of commodity futures on portfolio performance by explicitly incorporating levered futures into the portfolio optimization problem. Using data on nine individual commodity

Log-Optimal Portfolio Selection Using the Blackwell Approachability Theorem

OpenAIRE

V'yugin, Vladimir

2014-01-01

We present a method for constructing the log-optimal portfolio using the well-calibrated forecasts of market values. Dawid's notion of calibration and the Blackwell approachability theorem are used for computing well-calibrated forecasts. We select a portfolio using this "artificial" probability distribution of market values. Our portfolio performs asymptotically at least as well as any stationary portfolio that redistributes the investment at each round using a continuous function of side in...

Linearly Adjustable International Portfolios

International Nuclear Information System (INIS)

Fonseca, R. J.; Kuhn, D.; Rustem, B.

2010-01-01

We present an approach to multi-stage international portfolio optimization based on the imposition of a linear structure on the recourse decisions. Multiperiod decision problems are traditionally formulated as stochastic programs. Scenario tree based solutions however can become intractable as the number of stages increases. By restricting the space of decision policies to linear rules, we obtain a conservative tractable approximation to the original problem. Local asset prices and foreign exchange rates are modelled separately, which allows for a direct measure of their impact on the final portfolio value.

Linearly Adjustable International Portfolios

Science.gov (United States)

Fonseca, R. J.; Kuhn, D.; Rustem, B.

2010-09-01

We present an approach to multi-stage international portfolio optimization based on the imposition of a linear structure on the recourse decisions. Multiperiod decision problems are traditionally formulated as stochastic programs. Scenario tree based solutions however can become intractable as the number of stages increases. By restricting the space of decision policies to linear rules, we obtain a conservative tractable approximation to the original problem. Local asset prices and foreign exchange rates are modelled separately, which allows for a direct measure of their impact on the final portfolio value.

Agile Project Portfolio Management

DEFF Research Database (Denmark)

Andersen, Jesper Rank; Riis, Jens Ove; Mikkelsen, Hans

2005-01-01

This paper will provide a preliminary introduction to the application of Agile Thinking in management of project portfolio and company development. At any point in time, companies have a crowd of development initiatives spread around the organisation and managed at different levels...... in the managerial hierarchy. They compete for resources and managerial attention, and they often take too long time - and some do not survive in the rapid changing context. Top man¬agers ask for speed, flexibility and effectiveness in the portfolio of development activities (projects). But which competencies...

Natural gas contracts in efficient portfolios

Energy Technology Data Exchange (ETDEWEB)

Sutherland, R.J.

1994-12-01

This report addresses the {open_quotes}contracts portfolio{close_quotes} issue of natural gas contracts in support of the Domestic Natural Gas and Oil Initiative (DGOI) published by the U.S. Department of Energy in 1994. The analysis is a result of a collaborative effort with the Public Service Commission of the State of Maryland to consider {open_quotes}reforms that enhance the industry`s competitiveness{close_quotes}. The initial focus of our collaborative effort was on gas purchasing and contract portfolios; however, it became apparent that efficient contracting to purchase and use gas requires a broader consideration of regulatory reform. Efficient portfolios are obtained when the holder of the portfolio is affected by and is responsible for the performance of the portfolio. Natural gas distribution companies may prefer a diversity of contracts, but the efficient use of gas requires that the local distribution company be held accountable for its own purchases. Ultimate customers are affected by their own portfolios, which they manage efficiently by making their own choices. The objectives of the DGOI, particularly the efficient use of gas, can be achieved when customers have access to suppliers of gas and energy services under an improved regulatory framework. The evolution of the natural gas market during the last 15 years is described to account for the changing preferences toward gas contracts. Long-term contracts for natural gas were prevalent before the early 1980s, primarily because gas producers had few options other than to sell to a single pipeline company, and this pipeline company, in turn, was the only seller to a gas distribution company.

Learning Styles and e-portfolio in Nursing Education

DEFF Research Database (Denmark)

Nielsen, Kirsten; Pedersen, Birthe D.; Helms, Niels Henrik

Purpose of the study Research from UK and USA indicates that an e-portfolio facilitates a stronger connection between theoretical and clinical studies in Nursing Education. It helps students reflect over practice and their own skills. Yet other results show that an e-portfolio is a time consumer....... Thus, the aim of this project is to examine the effects of an e-portfolio on nursing students learning of patients with chronic illness during their clinical practice, and to investigate if it makes any difference in facilitating four learning styles: the activist, the reflector, the theorist...... through observations in clinical settings, narrative interviews, and print-outs from the students e-portfolio. Findings So far a pilot project with a questionnaire shows that 84% of the students and nurses reported that the e-portfolio has a positive effect on students learning in clinical settings...

An Extensive Evaluation of Portfolio Approaches for Constraint Satisfaction Problems

Directory of Open Access Journals (Sweden)

Roberto Amadini

2016-06-01

Full Text Available In the context of Constraint Programming, a portfolio approach exploits the complementary strengths of a portfolio of different constraint solvers. The goal is to predict and run the best solver(s of the portfolio for solving a new, unseen problem. In this work we reproduce, simulate, and evaluate the performance of different portfolio approaches on extensive benchmarks of Constraint Satisfaction Problems. Empirical results clearly show the benefits of portfolio solvers in terms of both solved instances and solving time.

IT Portfolio Selection and IT Synergy

Science.gov (United States)

Cho, Woo Je

2010-01-01

This dissertation consists of three chapters. The primary objectives of this dissertation are: (1) to provide a methodological framework of IT (Information Technology) portfolio management, and (2) to identify the effect of IT synergy on IT portfolio selection of a firm. The first chapter presents a methodological framework for IT project…

Portfolio Optimization in a Semi-Markov Modulated Market

International Nuclear Information System (INIS)

Ghosh, Mrinal K.; Goswami, Anindya; Kumar, Suresh K.

2009-01-01

We address a portfolio optimization problem in a semi-Markov modulated market. We study both the terminal expected utility optimization on finite time horizon and the risk-sensitive portfolio optimization on finite and infinite time horizon. We obtain optimal portfolios in relevant cases. A numerical procedure is also developed to compute the optimal expected terminal utility for finite horizon problem

Student Chemical Engineering Reflective ePortfolios--ChE Student Perceptions of Learning from Reflective ePortfolio Creation

Science.gov (United States)

Cherrstrom, Catherine A.; Raisor, Cindy; Fowler, Debra

2015-01-01

Engineering educators and employers value and prioritize communication skills, but developing and assessing such skills in engineering programs is challenging. Reflective ePortfolios provide opportunities to enhance communication skills. The purpose of this three-­year qualitative case study was to investigate the use of reflective ePortfolios in…

Digital portfolio for learning: A new communication channel for education

Directory of Open Access Journals (Sweden)

Judit Coromina

2011-04-01

Full Text Available Purpose: The Catalonian Government has the intention of introducing the digital portfolio before 2017, an initiative related to new approaches for learning. Taking in consideration the increasing interest for digital portfolio as a new communication channel for education, the article aims are: on the one hand to describe how the digital portfolio works and on the other hand, to identify a list of criteria that should be useful for educative centers to select the best application to create the digital portfolio according to their needs.Design/methodology/approach: Firstly, a theoretical framework for portfolio functioning is described. After, applications to support the digital portfolio are classified. Next, a requirement analysis on an ideal application to support the portfolio is made, according to those phases for the portfolio creation identified in the theoretical framework. Lastly, a list of criteria is established to select the application for creating the digital portfolio.Findings and Originality/value: The article contributes to structure the portfolio creation process in some stages and phases in a wider way that it is described in the literature. In addition, a list of criteria is defined to help educative centers to select the application for managing the portfolio that fits better with their objectives. These criteria have been obtained with an exhaustive methodology.Research limitations/implications: In order to put in practice the identified criteria it is proposed to complete the multi-criteria decision model in a new study. It should include processes to weigh criteria and define normalizations. Afterwards it would be able to analyze the value of the model studying the satisfaction for using it by a sample of educative centers.Practical implications: The list of criteria identified should facilitate the selection of the more adequate application to create the learning portfolio to the educative centers, according to their

A Risk-Sensitive Portfolio Optimization Problem with Fixed Incomes Securities

OpenAIRE

Goel, Mayank; Kumar, K. Suresh

2007-01-01

We discuss a class of risk-sensitive portfolio optimization problems. We consider the portfolio optimization model investigated by Nagai in 2003. The model by its nature can include fixed income securities as well in the portfolio. Under fairly general conditions, we prove the existence of optimal portfolio in both finite and infinite horizon problems.

Portfolio use and practices in US colleges and schools of pharmacy.

Science.gov (United States)

Skrabal, Maryann Z; Turner, Paul D; Jones, Rhonda M; Tilleman, Jennifer A; Coover, Kelli L

2012-04-10

To identify the prevalence of portfolio use in US pharmacy programs, common components of portfolios, and advantages of and limitations to using portfolios. A cross-sectional electronic survey instrument was sent to experiential coordinators at US colleges and schools of pharmacy to collect data on portfolio content, methods, training and resource requirements, and benefits and challenges of portfolio use. Most colleges and schools of pharmacy (61.8%) use portfolios in experiential courses and the majority (67.1%) formally assess them, but there is wide variation regarding content and assessment. The majority of respondents used student portfolios as a formative evaluation primarily in the experiential curriculum. Although most colleges and schools of pharmacy have a portfolio system in place, few are using them to fulfill accreditation requirements. Colleges and schools need to carefully examine the intended purpose of their portfolio system and follow-through with implementation and maintenance of a system that meets their goals.

Portfolio selection between rational and behavioral theories emergent markets case

Directory of Open Access Journals (Sweden)

Bouri Abdelfatteh

2012-08-01

Full Text Available The aim of this paper is to explore the determinants of Portfolio Choice under the investors, professionals and academics’ perception. We introduce an approach based on cognitive mapping technique with a series of semi-directive interviews. Among a sample of 30 Tunisian individuals, we propose tow different frameworks: a mean-variance framework and a behavioral framework. Each framework is oriented to capture the effect of some concepts as proposed by the mean-variance portfolio theory and the behavioral portfolio theory on the portfolio choice decision. The originality of this research paper is guaranteed since it traits the behavioral portfolio choice in emergent markets. In the best of our knowledge this is the first study in the Tunisian context that explores such area of research. Ours results show that the Tunisian investors behave as it prescribed by the behavioral portfolio theory. They use some concepts proposed by the rational mean-variance theory of portfolio choice but they are affected by their emotions and some others cognitive bias when constructing and managing they portfolio of assets.

EPOCA/EUR-OCEANS data compilation on the biological and biogeochemical responses to ocean acidification

OpenAIRE

Nisumaa Anne-Marin; Pesant Stephane; Bellerby Richard G J; Delille Bruno; Middelburg Jack J; Orr James C; Riebesell Ulf; Tyrrell Toby; Wolf-Gladrow Dieter A; Gattuso Jean-Pierre

2010-01-01

The uptake of anthropogenic CO₂ by the oceans has led to a rise in the oceanic partial pressure of CO₂, and to a decrease in pH and carbonate ion concentration. This modification of the marine carbonate system is referred to as ocean acidification. Numerous papers report the effects of ocean acidification on marine organisms and communities but few have provided details concerning full carbonate chemistry and complementary observations. Additional...

Twelve tips for successful e-tutoring using electronic portfolios.

Science.gov (United States)

Deketelaere, Ann; Degryse, Jan; De Munter, Agnes; De Leyn, Paul

2009-06-01

E-tutoring by means of a digital portfolio offers personal guidance in a context in which regular face-to-face contact between supervisor and student is difficult. However, implementing e-tutoring in practice is not always straightforward. This article investigates the conditions for successful e-tutoring of electronic portfolios. A combination of three methods is used: our own experience with e-tutoring, interviews with 14 tutors using an e-portfolio and the answers on questionnaires by 107 students. We present 12 tips to increase the chances of successful e-tutoring when using electronic portfolios. E-tutoring by means of electronic portfolios can be a feasible alternative in contexts in which face-to-face tutoring is difficult.

Radioactivity in the ocean: laws and biological effects

Energy Technology Data Exchange (ETDEWEB)

Hunsaker, C.T.

1985-01-01

This paper summarizes the literature on US laws and international agreements, experimental and monitoring data, and ongoing studies to provide background information for environmental assessment and regulatory compliance activities for ocean dumping of low-level radioactive waste. The Marine Protection, Research, and Sanctuaries Act is the major US legislation governing ocean disposal of radioactive waste. The major international agreement on ocean dumping is the Convention on the Prevention of Marine Pollution by Dumping of Wastes and other Matter. The United States ended its ocean dumping of radioactive wastes in 1970, but other countries have continued ocean dumping under international supervision in the northeast Atlantic. Monitoring of former US disposal sites has neither revealed significant effects on marine biota nor indicated a hazard to human health. Also, no effects on marine organisms have been found that could be attributed to routine discharges into the Irish Sea from the Windscale reprocessing plant. We must improve our ability to predict the oceanic carrying capacity and the fate and effects of ionizing radiation in the marine environment.

Radioactivity in the ocean: laws and biological effects

International Nuclear Information System (INIS)

Hunsaker, C.T.

1985-01-01

This paper summarizes the literature on US laws and international agreements, experimental and monitoring data, and ongoing studies to provide background information for environmental assessment and regulatory compliance activities for ocean dumping of low-level radioactive waste. The Marine Protection, Research, and Sanctuaries Act is the major US legislation governing ocean disposal of radioactive waste. The major international agreement on ocean dumping is the Convention on the Prevention of Marine Pollution by Dumping of Wastes and other Matter. The United States ended its ocean dumping of radioactive wastes in 1970, but other countries have continued ocean dumping under international supervision in the northeast Atlantic. Monitoring of former US disposal sites has neither revealed significant effects on marine biota nor indicated a hazard to human health. Also, no effects on marine organisms have been found that could be attributed to routine discharges into the Irish Sea from the Windscale reprocessing plant. We must improve our ability to predict the oceanic carrying capacity and the fate and effects of ionizing radiation in the marine environment

SunShot Initiative Portfolio Book 2014

Energy Technology Data Exchange (ETDEWEB)

Solar Energy Technologies Office

2014-05-01

The 2014 SunShot Initiative Portfolio Book outlines the progress towards the goals outlined in the SunShot Vision Study. Contents include overviews of each of SunShot’s five subprogram areas, as well as a description of every active project in the SunShot’s project portfolio as of May 2014.

Guidelines for Good Evaluation Practice with the ACUMEN portfolio

DEFF Research Database (Denmark)

Wildgaard, Lorna Elizabeth

2014-01-01

This document gives guidelines for using the ACUMEN Portfolio to evaluate academic researchers. The ACUMEN Portfolio is a way for Portfolio owners to highlight their achievements and to present themselves in the most positive way. It supplements the traditional CV because it highlights key achiev...

Selection of risk reduction portfolios under interval-valued probabilities

International Nuclear Information System (INIS)

Toppila, Antti; Salo, Ahti

2017-01-01

A central problem in risk management is that of identifying the optimal combination (or portfolio) of improvements that enhance the reliability of the system most through reducing failure event probabilities, subject to the availability of resources. This optimal portfolio can be sensitive with regard to epistemic uncertainties about the failure events' probabilities. In this paper, we develop an optimization model to support the allocation of resources to improvements that mitigate risks in coherent systems in which interval-valued probabilities defined by lower and upper bounds are employed to capture epistemic uncertainties. Decision recommendations are based on portfolio dominance: a resource allocation portfolio is dominated if there exists another portfolio that improves system reliability (i) at least as much for all feasible failure probabilities and (ii) strictly more for some feasible probabilities. Based on non-dominated portfolios, recommendations about improvements to implement are derived by inspecting in how many non-dominated portfolios a given improvement is contained. We present an exact method for computing the non-dominated portfolios. We also present an approximate method that simplifies the reliability function using total order interactions so that larger problem instances can be solved with reasonable computational effort. - Highlights: • Reliability allocation under epistemic uncertainty about probabilities. • Comparison of alternatives using dominance. • Computational methods for generating the non-dominated alternatives. • Deriving decision recommendations that are robust with respect to epistemic uncertainty.

Fault Tolerant Distributed Portfolio Optimization in Smart Grids

DEFF Research Database (Denmark)

Juelsgaard, Morten; Wisniewski, Rafal; Bendtsen, Jan Dimon

2014-01-01

optimization scheme for power balancing, where communication is allowed only between units that are linked in the graph. We include consumers with controllable consumption as an active part of the portfolio. We show that a suboptimal, but arbitrarily good power balancing can be obtained in an uncoordinated......, distributed optimization framework, and argue that the scheme will work even if the computation time is limited. We further show that our approach can tolerate changes in the portfolio, in the sense that increasing or reducing the number of units in the portfolio requires only local updates. This ensures......This work considers a portfolio of units for electrical power production and the problem of utilizing it to maintain power balance in the electrical grid. We treat the portfolio as a graph in which the nodes are distributed generators and the links are communication paths. We present a distributed...

Real Time Investments with Adequate Portfolio Theory

Directory of Open Access Journals (Sweden)

Alina Kvietkauskienė

2015-02-01

Full Text Available The objective of this paper is to identify investment decision makingschemes using the adequate portfolio model. This approach can be employed to project investment in stocks, using the opportunities offered by the markets and investor intelligence. It was decided to use adequate portfolio theory for investment decision making, simulation of financial markets, and optimisation of utility function. The main conclusion of article suggests investigating return on individual portfolio level. Real investment is a way to make sure of the soundness of applicable strategies.

Quantitative Portfolio Optimization Techniques Applied to the Brazilian Stock Market

Directory of Open Access Journals (Sweden)

André Alves Portela Santos

2012-09-01

Full Text Available In this paper we assess the out-of-sample performance of two alternative quantitative portfolio optimization techniques - mean-variance and minimum variance optimization – and compare their performance with respect to a naive 1/N (or equally-weighted portfolio and also to the market portfolio given by the Ibovespa. We focus on short selling-constrained portfolios and consider alternative estimators for the covariance matrices: sample covariance matrix, RiskMetrics, and three covariance estimators proposed by Ledoit and Wolf (2003, Ledoit and Wolf (2004a and Ledoit and Wolf (2004b. Taking into account alternative portfolio re-balancing frequencies, we compute out-of-sample performance statistics which indicate that the quantitative approaches delivered improved results in terms of lower portfolio volatility and better risk-adjusted returns. Moreover, the use of more sophisticated estimators for the covariance matrix generated optimal portfolios with lower turnover over time.

The Southern Ocean biogeochemical divide.

Science.gov (United States)

Marinov, I; Gnanadesikan, A; Toggweiler, J R; Sarmiento, J L

2006-06-22

Modelling studies have demonstrated that the nutrient and carbon cycles in the Southern Ocean play a central role in setting the air-sea balance of CO(2) and global biological production. Box model studies first pointed out that an increase in nutrient utilization in the high latitudes results in a strong decrease in the atmospheric carbon dioxide partial pressure (pCO2). This early research led to two important ideas: high latitude regions are more important in determining atmospheric pCO2 than low latitudes, despite their much smaller area, and nutrient utilization and atmospheric pCO2 are tightly linked. Subsequent general circulation model simulations show that the Southern Ocean is the most important high latitude region in controlling pre-industrial atmospheric CO(2) because it serves as a lid to a larger volume of the deep ocean. Other studies point out the crucial role of the Southern Ocean in the uptake and storage of anthropogenic carbon dioxide and in controlling global biological production. Here we probe the system to determine whether certain regions of the Southern Ocean are more critical than others for air-sea CO(2) balance and the biological export production, by increasing surface nutrient drawdown in an ocean general circulation model. We demonstrate that atmospheric CO(2) and global biological export production are controlled by different regions of the Southern Ocean. The air-sea balance of carbon dioxide is controlled mainly by the biological pump and circulation in the Antarctic deep-water formation region, whereas global export production is controlled mainly by the biological pump and circulation in the Subantarctic intermediate and mode water formation region. The existence of this biogeochemical divide separating the Antarctic from the Subantarctic suggests that it may be possible for climate change or human intervention to modify one of these without greatly altering the other.

Portfolio optimization by using linear programing models based on genetic algorithm

Science.gov (United States)

Sukono; Hidayat, Y.; Lesmana, E.; Putra, A. S.; Napitupulu, H.; Supian, S.

2018-01-01

In this paper, we discussed the investment portfolio optimization using linear programming model based on genetic algorithms. It is assumed that the portfolio risk is measured by absolute standard deviation, and each investor has a risk tolerance on the investment portfolio. To complete the investment portfolio optimization problem, the issue is arranged into a linear programming model. Furthermore, determination of the optimum solution for linear programming is done by using a genetic algorithm. As a numerical illustration, we analyze some of the stocks traded on the capital market in Indonesia. Based on the analysis, it is shown that the portfolio optimization performed by genetic algorithm approach produces more optimal efficient portfolio, compared to the portfolio optimization performed by a linear programming algorithm approach. Therefore, genetic algorithms can be considered as an alternative on determining the investment portfolio optimization, particularly using linear programming models.

Information Acquisition and Portfolio Performance

OpenAIRE

Guiso, Luigi; Jappelli, Tullio

2006-01-01

Rational investors perceive correctly the value of financial information. Investment in information is therefore rewarded with a higher Sharpe ratio. Overconfident investors overstate the quality of their own information, and thus attain a lower Sharpe ratio. We contrast the implications of the two models using a unique survey of customers of an Italian leading bank with portfolio data and measures of financial information. We find that the portfolio Sharpe ratio is negatively associated with...

Mentoring portfolio use in undergraduate and postgraduate medical education

NARCIS (Netherlands)

Dekker, Hanke; Driessen, Erik; Ter Braak, Edith; Scheele, Fedde; Slaets, Joris; Van Der Molen, Thys; Cohen-Schotanus, Janke

2009-01-01

Aim: Mentoring is widely acknowledged as being crucial for portfolio learning. The aim of this study is to examine how mentoring portfolio use has been implemented in undergraduate and postgraduate settings. Method: The results of interviews with six key persons involved in setting up portfolio use

Land-Use Portfolio Modeler, Version 1.0

Science.gov (United States)

Taketa, Richard; Hong, Makiko

2010-01-01

Natural hazards pose significant threats to the public safety and economic health of many communities throughout the world. Community leaders and decision-makers continually face the challenges of planning and allocating limited resources to invest in protecting their communities against catastrophic losses from natural-hazard events. Public efforts to assess community vulnerability and encourage loss-reduction measures through mitigation often focused on either aggregating site-specific estimates or adopting standards based upon broad assumptions about regional risks. The site-specific method usually provided the most accurate estimates, but was prohibitively expensive, whereas regional risk assessments were often too general to be of practical use. Policy makers lacked a systematic and quantitative method for conducting a regional-scale risk assessment of natural hazards. In response, Bernknopf and others developed the portfolio model, an intermediate-scale approach to assessing natural-hazard risks and mitigation policy alternatives. The basis for the portfolio-model approach was inspired by financial portfolio theory, which prescribes a method of optimizing return on investment while reducing risk by diversifying investments in different security types. In this context, a security type represents a unique combination of features and hazard-risk level, while financial return is defined as the reduction in losses resulting from an investment in mitigation of chosen securities. Features are selected for mitigation and are modeled like investment portfolios. Earth-science and economic data for the features are combined and processed in order to analyze each of the portfolios, which are then used to evaluate the benefits of mitigating the risk in selected locations. Ultimately, the decision maker seeks to choose a portfolio representing a mitigation policy that maximizes the expected return-on-investment, while minimizing the uncertainty associated with that return

Household portfolios and risk taking over age and time

NARCIS (Netherlands)

Bucciol, A.; Miniaci, R.

2011-01-01

We exploit the US Survey of Consumer Finances (SCF) from 1998 to 2007 to provide new insights on the evolution of US households’ willingness to undertake portfolio risk. Specifically, we consider four alternative measures of portfolio risk, based on two definitions of portfolio - a narrow one,

Acreage portfolio management

International Nuclear Information System (INIS)

Schneider, G.M.

1992-01-01

This paper reports that the need for managing the acreage portfolio in the UK North Sea arises from fragmentation of holdings and complex field partnerships. The main concepts are building up the heartlands and balancing cashflow forecasts. This has generated a number of friendly win-win deals, motivated by differences in perception of values. The business process includes identifying, evaluating and negotiating deals. The Petroleum Economist plays a central role throughout this process, seeking value gaps and supporting negotiations. Variations in reserves estimates present a major source of value gaps between buyer and seller. Economists need to work closely with engineers and geologists. Portfolio management is an exciting and challenging task which broadens the traditional role of the Petroleum Economist

A Robust Statistics Approach to Minimum Variance Portfolio Optimization

Science.gov (United States)

Yang, Liusha; Couillet, Romain; McKay, Matthew R.

2015-12-01

We study the design of portfolios under a minimum risk criterion. The performance of the optimized portfolio relies on the accuracy of the estimated covariance matrix of the portfolio asset returns. For large portfolios, the number of available market returns is often of similar order to the number of assets, so that the sample covariance matrix performs poorly as a covariance estimator. Additionally, financial market data often contain outliers which, if not correctly handled, may further corrupt the covariance estimation. We address these shortcomings by studying the performance of a hybrid covariance matrix estimator based on Tyler's robust M-estimator and on Ledoit-Wolf's shrinkage estimator while assuming samples with heavy-tailed distribution. Employing recent results from random matrix theory, we develop a consistent estimator of (a scaled version of) the realized portfolio risk, which is minimized by optimizing online the shrinkage intensity. Our portfolio optimization method is shown via simulations to outperform existing methods both for synthetic and real market data.

Optimization of the bank's operating portfolio

Science.gov (United States)

Borodachev, S. M.; Medvedev, M. A.

2016-06-01

The theory of efficient portfolios developed by Markowitz is used to optimize the structure of the types of financial operations of a bank (bank portfolio) in order to increase the profit and reduce the risk. The focus of this paper is to check the stability of the model to errors in the original data.

Portfolio optimization using median-variance approach

Science.gov (United States)

Wan Mohd, Wan Rosanisah; Mohamad, Daud; Mohamed, Zulkifli

2013-04-01

Optimization models have been applied in many decision-making problems particularly in portfolio selection. Since the introduction of Markowitz's theory of portfolio selection, various approaches based on mathematical programming have been introduced such as mean-variance, mean-absolute deviation, mean-variance-skewness and conditional value-at-risk (CVaR) mainly to maximize return and minimize risk. However most of the approaches assume that the distribution of data is normal and this is not generally true. As an alternative, in this paper, we employ the median-variance approach to improve the portfolio optimization. This approach has successfully catered both types of normal and non-normal distribution of data. With this actual representation, we analyze and compare the rate of return and risk between the mean-variance and the median-variance based portfolio which consist of 30 stocks from Bursa Malaysia. The results in this study show that the median-variance approach is capable to produce a lower risk for each return earning as compared to the mean-variance approach.

A diversified portfolio model of adaptability.

Science.gov (United States)

Chandra, Siddharth; Leong, Frederick T L

2016-12-01

A new model of adaptability, the diversified portfolio model (DPM) of adaptability, is introduced. In the 1950s, Markowitz developed the financial portfolio model by demonstrating that investors could optimize the ratio of risk and return on their portfolios through risk diversification. The DPM integrates attractive features of a variety of models of adaptability, including Linville's self-complexity model, the risk and resilience model, and Bandura's social cognitive theory. The DPM draws on the concept of portfolio diversification, positing that diversified investment in multiple life experiences, life roles, and relationships promotes positive adaptation to life's challenges. The DPM provides a new integrative model of adaptability across the biopsychosocial levels of functioning. More importantly, the DPM addresses a gap in the literature by illuminating the antecedents of adaptive processes studied in a broad array of psychological models. The DPM is described in relation to the biopsychosocial model and propositions are offered regarding its utility in increasing adaptiveness. Recommendations for future research are also offered. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

The impact on atmospheric CO2 of iron fertilization induced changes in the ocean's biological pump

Science.gov (United States)

Jin, X.; Gruber, N.; Frenzel, H.; Doney, S. C.; McWilliams, J. C.

2008-03-01

Using numerical simulations, we quantify the impact of changes in the ocean's biological pump on the air-sea balance of CO2 by fertilizing a small surface patch in the high-nutrient, low-chlorophyll region of the eastern tropical Pacific with iron. Decade-long fertilization experiments are conducted in a basin-scale, eddy-permitting coupled physical/biogeochemical/ecological model. In contrast to previous studies, we find that most of the dissolved inorganic carbon (DIC) removed from the euphotic zone by the enhanced biological export is replaced by uptake of CO2 from the atmosphere. Atmospheric uptake efficiencies, the ratio of the perturbation in air-sea CO2 flux to the perturbation in export flux across 100 m, integrated over 10 years, are 0.75 to 0.93 in our patch size-scale experiments. The atmospheric uptake efficiency is insensitive to the duration of the experiment. The primary factor controlling the atmospheric uptake efficiency is the vertical distribution of the enhanced biological production and export. Iron fertilization at the surface tends to induce production anomalies primarily near the surface, leading to high efficiencies. In contrast, mechanisms that induce deep production anomalies (e.g. altered light availability) tend to have a low uptake efficiency, since most of the removed DIC is replaced by lateral and vertical transport and mixing. Despite high atmospheric uptake efficiencies, patch-scale iron fertilization of the ocean's biological pump tends to remove little CO2 from the atmosphere over the decadal timescale considered here.

Teaching ePortfolios in Teacher Education

Directory of Open Access Journals (Sweden)

Peter Groißböck

2012-11-01

Full Text Available Especially when starting their career in the induction phase, young teachers need personal, profession-related and social support. Young teachers can get personal support with a mentoring system, profession-related support in seminars and social support with peer-learning. E-portfolios offer ways to accompany those learning processes and are a central tool for the documentation of individual student progress in the induction phase of teachers. In this article a concept of teaching e-portfolios for the induction phase is presented, showing a basic structure, essential conditions and possible risks. Additionally this article also includes practical thoughts to the use of e-portfolios in basic teacher education and further teacher training.

Portfolio Selection Using Level Crossing Analysis

Science.gov (United States)

Bolgorian, Meysam; Shirazi, A. H.; Jafari, G. R.

Asset allocation is one of the most important and also challenging issues in finance. In this paper using level crossing analysis we introduce a new approach for portfolio selection. We introduce a portfolio index that is obtained based on minimizing the waiting time to receive known return and risk values. By the waiting time, we mean time that a special level is observed in average. The advantage of this approach is that the investors are able to set their goals based on gaining return and knowing the average waiting time and risk value at the same time. As an example we use our model for forming portfolio of stocks in Tehran Stock Exchange (TSE).

The Role of Learning- and Presentation- Portfolios in Design Educations

DEFF Research Database (Denmark)

Thomsen, Bente Dahl; Ovesen, Nis

2014-01-01

Students that primarily study design through team-based projects often struggle to develop presentation portfolios that differentiate from the ones of other students. In the industry, design managers experience this as a problem, as they often receive job applications with presentation portfolios...... resources from other activities, which is why the templates have to be carefully balanced in order to achieve the desired effect. The portfolio method proved to be especially good at illustrating process related competencies.......Students that primarily study design through team-based projects often struggle to develop presentation portfolios that differentiate from the ones of other students. In the industry, design managers experience this as a problem, as they often receive job applications with presentation portfolios...... of the portfolio method in engineering design educations, this research project has investigated the method as part of a course programme. The preliminary experiments and results show that learning portfolio templates are effective in strengthening certain activities. On the other hand, the method risks draining...

Marine biology

International Nuclear Information System (INIS)

Thurman, H.V.; Webber, H.H.

1984-01-01

This book discusses both taxonomic and ecological topics on marine biology. Full coverage of marine organisms of all five kingdoms is provided, along with interesting and thorough discussion of all major marine habitats. Organization into six major parts allows flexibility. It also provides insight into important topics such as disposal of nuclear waste at sea, the idea that life began on the ocean floor, and how whales, krill, and people interact. A full-color photo chapter reviews questions, and exercises. The contents are: an overview marine biology: fundamental concepts/investigating life in the ocean; the physical ocean, the ocean floor, the nature of water, the nature and motion of ocean water; general ecology, conditions for life in the sea, biological productivity and energy transfer; marine organisms; monera, protista, mycota and metaphyta; the smaller marine animals, the large animals marine habitats, the intertidal zone/benthos of the continental shelf, the photic zone, the deep ocean, the ocean under stress, marine pollution, appendix a: the metric system and conversion factors/ appendix b: prefixes and suffixes/ appendix c: taxonomic classification of common marine organisms, and glossary, and index

PORTFOLIO COMPOSITION WITH MINIMUM VARIANCE: COMPARISON WITH MARKET BENCHMARKS

Directory of Open Access Journals (Sweden)

Daniel Menezes Cavalcante

2016-07-01

Full Text Available Portfolio optimization strategies are advocated as being able to allow the composition of stocks portfolios that provide returns above market benchmarks. This study aims to determine whether, in fact, portfolios based on the minimum variance strategy, optimized by the Modern Portfolio Theory, are able to achieve earnings above market benchmarks in Brazil. Time series of 36 securities traded on the BM&FBOVESPA have been analyzed in a long period of time (1999-2012, with sample windows of 12, 36, 60 and 120 monthly observations. The results indicated that the minimum variance portfolio performance is superior to market benchmarks (CDI and IBOVESPA in terms of return and risk-adjusted return, especially in medium and long-term investment horizons.

Spin glasses and nonlinear constraints in portfolio optimization

International Nuclear Information System (INIS)

Andrecut, M.

2014-01-01

We discuss the portfolio optimization problem with the obligatory deposits constraint. Recently it has been shown that as a consequence of this nonlinear constraint, the solution consists of an exponentially large number of optimal portfolios, completely different from each other, and extremely sensitive to any changes in the input parameters of the problem, making the concept of rational decision making questionable. Here we reformulate the problem using a quadratic obligatory deposits constraint, and we show that from the physics point of view, finding an optimal portfolio amounts to calculating the mean-field magnetizations of a random Ising model with the constraint of a constant magnetization norm. We show that the model reduces to an eigenproblem, with 2N solutions, where N is the number of assets defining the portfolio. Also, in order to illustrate our results, we present a detailed numerical example of a portfolio of several risky common stocks traded on the Nasdaq Market.

Spin glasses and nonlinear constraints in portfolio optimization

Energy Technology Data Exchange (ETDEWEB)

Andrecut, M., E-mail: mircea.andrecut@gmail.com

2014-01-17

We discuss the portfolio optimization problem with the obligatory deposits constraint. Recently it has been shown that as a consequence of this nonlinear constraint, the solution consists of an exponentially large number of optimal portfolios, completely different from each other, and extremely sensitive to any changes in the input parameters of the problem, making the concept of rational decision making questionable. Here we reformulate the problem using a quadratic obligatory deposits constraint, and we show that from the physics point of view, finding an optimal portfolio amounts to calculating the mean-field magnetizations of a random Ising model with the constraint of a constant magnetization norm. We show that the model reduces to an eigenproblem, with 2N solutions, where N is the number of assets defining the portfolio. Also, in order to illustrate our results, we present a detailed numerical example of a portfolio of several risky common stocks traded on the Nasdaq Market.

Robust portfolio selection under norm uncertainty

Directory of Open Access Journals (Sweden)

Lei Wang

2016-06-01

Full Text Available Abstract In this paper, we consider the robust portfolio selection problem which has a data uncertainty described by the ( p , w $(p,w$ -norm in the objective function. We show that the robust formulation of this problem is equivalent to a linear optimization problem. Moreover, we present some numerical results concerning our robust portfolio selection problem.

MOSEP – More Self-Esteem With My E-Portfolio Development of a Train-the-Trainer Course for E-Portfolio Tutors

Directory of Open Access Journals (Sweden)

Wolf Hilzensauer

2009-03-01

Full Text Available E-portfolios are known as a technology- supported learning method for the documentation of competency development. In this article the didactic approach, the course design and the results of the Leonardo da Vinci project MOSEP (More self-esteem with my e-portfolio are described. The main objective of the project was to develop, test and evaluate a new e-portfolio training concept for teachers and tutors in order to support learners during their competence development phase.

Portfolio Diversification in the South-East European Equity Markets

Directory of Open Access Journals (Sweden)

Zaimovic Azra

2017-04-01

Full Text Available Diversification potential enables investors to manage their risk and decrease risk exposure. Good diversification policy is a safety net that prevents a portfolio from losing its value. A well-diversified portfolio consists of different categories of property with low correlations, while highly correlated markets have the feature of low possibilities for diversification. The biggest riddle in the world of investments is to find the optimal portfolio within a set of available assets with limited capital. There are numerous studies and mathematical models that deal with portfolio investment strategies. These strategies take advantage of diversification by spreading risk over several financial assets. Modern portfolio theory seeks to find the optimal model with the best results. This paper tries to identify relationships between returns of companies traded in South-East European equity markets. A Markowitz mean-variance (MV portfolio optimization method is used to identify possibilities for diversification among these markets and world leading capital markets. This research also offers insight into to the level of integration of South-East European equity markets. Principal component analysis (PCA is used to determine components that describe the strong patterns and co-movements of the dataset. Finally, we combined MV efficient frontier and equity, which represent PCA components, to draw conclusions. Our findings show that PC analysis substantially simplifies asset selection process in portfolio management. The results of the paper have practical applications for portfolio investors.

Portfolio optimization with structured products under return constraint

Directory of Open Access Journals (Sweden)

Baweja Meena

2015-01-01

Full Text Available A new approach for optimizing risk in a portfolio of financial instruments involving structured products is presented. This paper deals with a portfolio selection model which uses optimization methodology to minimize conditional Value-at-Risk (CVaR under return constraint. It focuses on minimizing CVaR rather than on minimizing value-at-Risk VaR, as portfolios with low CVaR necessarily have low VaR as well. We consider a simple investment problem where besides stocks and bonds, the investor can also include structured products into the investment portfolio. Due to possible intermediate payments from structured product, we have to deal with a re-investment problem modeled as a linear optimization problem.

Future Learning Strategy and ePortfolios in Education

Directory of Open Access Journals (Sweden)

C. Dorninger

2008-03-01

Full Text Available The rapid change of the information andknowledge Society does no stop at education:communication, teaching and learning are changing due todigital media. Therefore at Austrian schools a “FutureLearning”- strategy was started in October 2007, where newforms of learning are underlined by new media and socialsoftware. This strategy will be presented. An important partof the strategy is the introduction of electronic Portfolios forstudents. Portfolios could be powerful tools to realizeindividualisation in formal education. There are two maintypes, the process portfolio for learning, working andreflection and the application portfolio for assessmentpurposes and job application. It is now possible to collectformal and informal competences and skills-orientedknowledge for the later professional career.

Applying the partitioned multiobjective risk method (PMRM) to portfolio selection.

Science.gov (United States)

Reyes Santos, Joost; Haimes, Yacov Y

2004-06-01

The analysis of risk-return tradeoffs and their practical applications to portfolio analysis paved the way for Modern Portfolio Theory (MPT), which won Harry Markowitz a 1992 Nobel Prize in Economics. A typical approach in measuring a portfolio's expected return is based on the historical returns of the assets included in a portfolio. On the other hand, portfolio risk is usually measured using volatility, which is derived from the historical variance-covariance relationships among the portfolio assets. This article focuses on assessing portfolio risk, with emphasis on extreme risks. To date, volatility is a major measure of risk owing to its simplicity and validity for relatively small asset price fluctuations. Volatility is a justified measure for stable market performance, but it is weak in addressing portfolio risk under aberrant market fluctuations. Extreme market crashes such as that on October 19, 1987 ("Black Monday") and catastrophic events such as the terrorist attack of September 11, 2001 that led to a four-day suspension of trading on the New York Stock Exchange (NYSE) are a few examples where measuring risk via volatility can lead to inaccurate predictions. Thus, there is a need for a more robust metric of risk. By invoking the principles of the extreme-risk-analysis method through the partitioned multiobjective risk method (PMRM), this article contributes to the modeling of extreme risks in portfolio performance. A measure of an extreme portfolio risk, denoted by f(4), is defined as the conditional expectation for a lower-tail region of the distribution of the possible portfolio returns. This article presents a multiobjective problem formulation consisting of optimizing expected return and f(4), whose solution is determined using Evolver-a software that implements a genetic algorithm. Under business-as-usual market scenarios, the results of the proposed PMRM portfolio selection model are found to be compatible with those of the volatility-based model

Selling an Energy Efficiency Loan Portfolio in Oregon: Resale of the Craft3 loan portfolio to Self-Help Credit Union

Energy Technology Data Exchange (ETDEWEB)

Thompson, Peter; Borgeson, Merrian; Kramer, Chris; Zimring, Mark; Goldman, Charles

2014-05-30

Under the Clean Energy Works (CEW) program, Craft3 developed a loan product that widened access to financing for homeowners, offered long term funding, and collected repayments through the customer?s utility bill. The program?s success led Craft3 to pursue the sale of the loan portfolio to both mitigate its own risks and replenish funds for lending. This sale breaks new ground for energy efficiency finance and is notable as it was completed even with many novel program design elements. It replenished Craft3?s program capital and uncovered some valuable lessons that may facilitate future transactions. However, the lack of data history and the unproven nature of the loan portfolio meant that Craft3 had to limit the risk of losses to Self-Help, the purchaser of the portfolio. It remains to be seen whether this experience will pave the way for more sales of on-bill energy efficiency loan portfolios. This case study illustrates how certain program design decisions can sometimes both facilitate programmatic objectives and possibly present challenges for the sale of a portfolio of energy efficiency loans.

Portfolio Management System

Data.gov (United States)

US Agency for International Development — PfMS is an implementation of WorkLenz. WorkLenz is USAID's portfolio management system tool. It is a commercially available, off-the-shelf (COTS) package that...

Wavelet evolutionary network for complex-constrained portfolio rebalancing

Science.gov (United States)

Suganya, N. C.; Vijayalakshmi Pai, G. A.

2012-07-01

Portfolio rebalancing problem deals with resetting the proportion of different assets in a portfolio with respect to changing market conditions. The constraints included in the portfolio rebalancing problem are basic, cardinality, bounding, class and proportional transaction cost. In this study, a new heuristic algorithm named wavelet evolutionary network (WEN) is proposed for the solution of complex-constrained portfolio rebalancing problem. Initially, the empirical covariance matrix, one of the key inputs to the problem, is estimated using the wavelet shrinkage denoising technique to obtain better optimal portfolios. Secondly, the complex cardinality constraint is eliminated using k-means cluster analysis. Finally, WEN strategy with logical procedures is employed to find the initial proportion of investment in portfolio of assets and also rebalance them after certain period. Experimental studies of WEN are undertaken on Bombay Stock Exchange, India (BSE200 index, period: July 2001-July 2006) and Tokyo Stock Exchange, Japan (Nikkei225 index, period: March 2002-March 2007) data sets. The result obtained using WEN is compared with the only existing counterpart named Hopfield evolutionary network (HEN) strategy and also verifies that WEN performs better than HEN. In addition, different performance metrics and data envelopment analysis are carried out to prove the robustness and efficiency of WEN over HEN strategy.

Implementation of Portfolio Assessment in a Competency-based Dental Hygiene Program.

Science.gov (United States)

Gadbury-Amyot, Cynthia C.; Holt, Lorie P.; Overman, Pamela R.; Schmidt, Colleen R.

2000-01-01

Describes the implementation of a portfolio assessment program in the dental hygiene program at the University of Missouri School of Dentistry. Tables provide examples of program competencies and related portfolio entries, the complete scoring rubric for portfolios, and the student portfolio evaluation survey. Concludes that although portfolio…

AN EXAMPLE FOR PORTFOLIO PREPARATION IN GERMAN TEACHER TRAINING

Directory of Open Access Journals (Sweden)

Hüseyin ARAK

2017-04-01

Full Text Available In this study we are trying with the help of portfolio in teacher training and the diagnosis of the learning group concerning their skills in translation from German to Turkish, to show the documentation of the learning process. The portfolio provides a good overview about the performance of the students and it also prepares a basis for assessment. A growing self-awareness of students can be achieved through implementing the portfolio-method. The students should collect and reflect the most important materials and practices leading to key terms of the seminar. It is more than an assessment method it is a surrounding of learning. The work with portfolio has an influence on teaching, learning and assessing. As in detail, this is dependent on the aims and other characteristics of the models which take the portfolio work as a basis. The portfolio provides us a big advantage for the support of the cultural reflection. We can observe the process of the growth of knowledge step by step, because the measurement of the development in a determined period allows us either a written work or a Multiple Choice Test. In this sense we can look at the portfolio as an assessment instrument of a process.

Asset Attribution Stability and Portfolio Construction: An Educational Example

Science.gov (United States)

Chong, James T.; Jennings, William P.; Phillips, G. Michael

2014-01-01

This paper illustrates how a third statistic from asset pricing models, the R-squared statistic, may have information that can help in portfolio construction. Using a traditional CAPM model in comparison to an 18-factor Arbitrage Pricing Style Model, a portfolio separation test is conducted. Portfolio returns and risk metrics are compared using…

Predictors and Portfolios Over the Life Cycle

DEFF Research Database (Denmark)

Kraft, Holger; Munk, Claus; Weiss, Farina

In a calibrated consumption-portfolio model with stock, housing, and labor income predictability, we evaluate the welfare effects of predictability on life-cycle consumption-portfolio choice. We compare skilled investors who are able to take advantage of all sources of predictability with unskilled...

Purchasing portfolio models: a critique and update

NARCIS (Netherlands)

Gelderman, C.J.; Weele, van A.J.

2005-01-01

Purchasing portfolio models have spawned considerable discussion in the literature. Many advantages and disadvantages have been put forward, revealing considerable divergence in opinion on the merits of portfolio models. This study addresses the question of whether or not the use of purchasing

Essays on intertemporal consumption and portfolio choice

NARCIS (Netherlands)

van Bilsen, Servaas

2015-01-01

This dissertation consists of two parts, preceded by an introductory chapter. Part I (Chapters 2, 3 and 4) considers optimal consumption and portfolio choice using preference models. Chapter 2 analyzes optimal consumption and portfolio choice under loss aversion and endogenous updating of the

ROMANIAN INVESTORS PORTFOLIO. ONLINE VERSUS ASSISTED TRADING

Directory of Open Access Journals (Sweden)

Ioana Ancuţa IANCU

2017-05-01

Full Text Available One of the most important aspects in deciding to trade online, alone, without the help of a broker, is the portfolio profitability. In this study, using the personal experience, survey data and secondary sources, we identify some factors that may influence the gain and the loss of investors which trade online. Our study contradicts other results from literature that claim that the transition from assisted to online trading is a big drawback in terms of portfolio profitability. By analyzing the performance of the portfolio when passing from assisted to online trading, we observe that half of the investors achieved identical profitability. We also observed that the efficiency of the portfolios belonging to the online investors that were assisted in the past by a broker for a short period, is lower compared to the ones assisted (in the past for a longer period.

Three Essays on Robust Optimization of Efficient Portfolios

OpenAIRE

Liu, Hao

2013-01-01

The mean-variance approach was first proposed by Markowitz (1952), and laid the foundation of the modern portfolio theory. Despite its theoretical appeal, the practical implementation of optimized portfolios is strongly restricted by the fact that the two inputs, the means and the covariance matrix of asset returns, are unknown and have to be estimated by available historical information. Due to the estimation risk inherited from inputs, desired properties of estimated optimal portfolios are ...

Contract portfolio optimization for a gasoline supply chain

Science.gov (United States)

Wang, Shanshan

Major oil companies sell gasoline through three channels of trade: branded (associated with long-term contracts), unbranded (associated with short-term contracts), and spot market. The branded channel provides them with a long-term secured and sustainable demand source, but requires an inflexible long-term commitment with demand and price risks. The unbranded channel provides a medium level of allocation flexibility. The spot market provides them with the greatest allocation flexibility to the changing market conditions, but the spot market's illiquidity mitigates this benefit. In order to sell the product in a profitable and sustainable way, they need an optimal contract portfolio. This dissertation addresses the contract portfolio optimization problem from different perspectives (retrospective view and forward-looking view) at different levels (strategic level, tactical level and operational level). The objective of the retrospective operational model is to develop a financial case to estimate the business value of having a dynamic optimization model and quantify the opportunity values missed in the past. This model proves the financial significance of the problem and provides top management valuable insights into the business. BP has applied the insights and principles gained from this work and implemented the model to the entire Midwest gasoline supply chain to retrospectively review optimization opportunities. The strategic model is the most parsimonious model that captures the essential economic tradeoffs among different contract types, to demonstrate the need for a contract portfolio and what drives the portfolio. We examine the properties of the optimal contract portfolio and provide a comparative statics analysis by changing the model parameters. As the strategic model encapsulates the business problem at the macroscopic level, the tactical model resolves lower level issues. It considers the time dynamics, the information flow and contracting flow. Using

Portfolio Manager Selection – A Case Study

DEFF Research Database (Denmark)

Christensen, Michael

2017-01-01

Within a delegated portfolio management setting, this paper presents a case study of how the manager selection process can be operationalized in practice. Investors have to pursue a thorough screening of potential portfolio managers in order to discover their quality, and this paper discusses how...

Declarative Modeling for Production Order Portfolio Scheduling

Directory of Open Access Journals (Sweden)

Banaszak Zbigniew

2014-12-01

Full Text Available A declarative framework enabling to determine conditions as well as to develop decision-making software supporting small- and medium-sized enterprises aimed at unique, multi-project-like and mass customized oriented production is discussed. A set of unique production orders grouped into portfolio orders is considered. Operations executed along different production orders share available resources following a mutual exclusion protocol. A unique product or production batch is completed while following a given activity’s network order. The problem concerns scheduling a newly inserted project portfolio subject to constraints imposed by a multi-project environment The answers sought are: Can a given project portfolio specified by its cost and completion time be completed within the assumed time period in a manufacturing system in hand? Which manufacturing system capability guarantees the completion of a given project portfolio ordered under assumed cost and time constraints? The considered problems regard finding a computationally effective approach aimed at simultaneous routing and allocation as well as batching and scheduling of a newly ordered project portfolio subject to constraints imposed by a multi-project environment. The main objective is to provide a declarative model enabling to state a constraint satisfaction problem aimed at multi-project-like and mass customized oriented production scheduling. Multiple illustrative examples are discussed.

Biological profile and meteorological data collected by bottle and net in the Western Pacific Ocean from 6/5/1973 - 11/7/1973 (NODC Accession 0000151)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Biological profile and meteorological data were collected using bottle and net casts from the RYOFU MARU in the Northwest / Southwest Pacific Ocean. Data were...

Management of Portfolio Investment Held by Pension Funds

Directory of Open Access Journals (Sweden)

Dan Armeanu

2008-09-01

Full Text Available As a result of the fact that pension funds are financial intermediaries, the value of their assets and liabilities is influenced by changing conditions in financial markets. The market image of a pension fund (and hence its perceived value are closely tied to the “financial health” of the fund. Setting up and managing complex investment portfolios requires that pension administrators use scientific models of portfolio selection and optimization based on the risk-expected return relationship. Most investment portfolios are modified in time as result of changing stock prices and investment policy objectives. Having established investment policy guidelines, the administrators of pension funds have to determine the structure of their portfolios so that the latter meet legal requirements.

The current account as a dynamic portfolio choice problem

OpenAIRE

Didier, Tatiana; Lowenkron, Alexandre

2009-01-01

The current account can be understood as the outcome of investment decisions made by domestic and foreign investors. These decisions can be decomposed into a portfolio rebalancing and a portfolio growth component. This paper provides empirical evidence of the importance of portfolio rebalancing for the dynamics of the current account. The authors evaluate the predictions of a partial-equil...

An Arbitrary Benchmark CAPM: One Additional Frontier Portfolio is Sufficient

OpenAIRE

Ekern, Steinar

2008-01-01

First draft: July 16, 2008 This version: October 7, 2008 The benchmark CAPM linearly relates the expected returns on an arbitrary asset, an arbitrary benchmark portfolio, and an arbitrary MV frontier portfolio. The benchmark is not required to be on the frontier and may be non-perfectly correlated with the frontier portfolio. The benchmark CAPM extends and generalizes previous CAPM formulations, including the zero beta, two correlated frontier portfolios, riskless augmented frontier, an...

Continuous-Time Mean-Variance Portfolio Selection under the CEV Process

OpenAIRE

Ma, Hui-qiang

2014-01-01

We consider a continuous-time mean-variance portfolio selection model when stock price follows the constant elasticity of variance (CEV) process. The aim of this paper is to derive an optimal portfolio strategy and the efficient frontier. The mean-variance portfolio selection problem is formulated as a linearly constrained convex program problem. By employing the Lagrange multiplier method and stochastic optimal control theory, we obtain the optimal portfolio strategy and mean-variance effici...

Methods of Choosing an Optimal Portfolio of Projects

OpenAIRE

Yakovlev, A.; Chernenko, M.

2016-01-01

This paper presents an analysis of existing methods for a portfolio of project optimization. The necessity for their improvement is shown. It is suggested to assess the portfolio of projects on the basis of the amount in the difference between the results and costs during development and implementation of selected projects and the losses caused by non-implementation or delayed implementation of projects that were not included in the portfolio. Consideration of capital and current costs compon...

PORTFOLIO OPTIMIZATION ON CROATIAN CAPITAL MARKET

Directory of Open Access Journals (Sweden)

Sinisa Bogdan

2013-12-01

Full Text Available Purpose of this paper was to research portfolio optimization problem on Croatian capital market using Markowitz theory. Research systematically investigated the selection of securities, and defined the importance of using fundamental analysis when selecting the best combination of securities. Since fundamental analysis involves a large number of indicators, this paper selected key indicators that enable a complete and quick securities review on the market. This paper clarifies diversification effect and influence of the correlation coefficient on diversification. Two basic types of assets (stocks and cash funds have been chosen to build the optimal portfolio. Cash funds were selected because they represent a form of risk-free investment, while stocks were chosen because of the high level of return which they achieve. At the end of paper, optimal portfolio was calculated with an excellent yield of 1.82% and deviation of 5.77% on a monthly basis which corresponds to the minimum deviation of the selected stocks. Calculated optimal portfolio achieves better expected value than investing in stock index CROBEX, which for the same period achieves the expected result of -0.02%.

Summertime calcium carbonate undersaturation in shelf waters of the western Arctic Ocean – how biological processes exacerbate the impact of ocean acidification

Directory of Open Access Journals (Sweden)

N. R. Bates

2013-08-01

Full Text Available The Arctic Ocean accounts for only 4% of the global ocean area, but it contributes significantly to the global carbon cycle. Recent observations of seawater CO2-carbonate chemistry in shelf waters of the western Arctic Ocean, primarily in the Chukchi Sea, from 2009 to 2011 indicate that bottom waters are seasonally undersaturated with respect to calcium carbonate (CaCO3 minerals, particularly aragonite. Nearly 40% of sampled bottom waters on the shelf have saturation states less than one for aragonite (i.e., Ωaragonite 3-secreting organisms, while 80% of bottom waters present had Ωaragonite values less than 1.5. Our observations indicate seasonal reduction of saturation states (Ω for calcite (Ωcalcite and aragonite (Ωaragonite in the subsurface in the western Arctic by as much as 0.8 and 0.5, respectively. Such data indicate that bottom waters of the western Arctic shelves were already potentially corrosive for biogenic and sedimentary CaCO3 for several months each year. Seasonal changes in Ω are imparted by a variety of factors such as phytoplankton photosynthesis, respiration/remineralization of organic matter and air–sea gas exchange of CO2. Combined, these processes either increase or enhance in surface and subsurface waters, respectively. These seasonal physical and biological processes also act to mitigate or enhance the impact of Anthropocene ocean acidification (OA on Ω in surface and subsurface waters, respectively. Future monitoring of the western Arctic shelves is warranted to assess the present and future impact of ocean acidification and seasonal physico-biogeochemical processes on Ω values and Arctic marine ecosystems.

e-Portfolio as reflection tool during teaching practice: The interplay ...

African Journals Online (AJOL)

This paper focuses on an e-portfolio pilot initiative at the Faculty of Education ... expectations of an e-portfolio aligns with the current practices and attributes ... will impact the potential success of the integration of e-portfolios as reflective tools.

Optimal Portfolio Choice with Wash Sale Constraints

DEFF Research Database (Denmark)

Astrup Jensen, Bjarne; Marekwica, Marcel

2011-01-01

We analytically solve the portfolio choice problem in the presence of wash sale constraints in a two-period model with one risky asset. Our results show that wash sale constraints can heavily affect portfolio choice of investors with unrealized losses. The trading behavior of such investors...

Delegated Portfolio Management and Optimal Allocation of Portfolio Managers

DEFF Research Database (Denmark)

Christensen, Michael; Vangsgaard Christensen, Michael; Gamskjaer, Ken

2015-01-01

In this article, we investigate whether the application of the mean-variance framework on portfolio manager allocation offers any out-of-sample benefits compared to a naïve strategy of equal weighting. Based on an exclusive data-set of high-net-worth (HNW) investors, we utilize a wide variety of ...

The influence of volatility spill-overs and market beta on portfolio construction

Directory of Open Access Journals (Sweden)

André Heymans

2015-05-01

Full Text Available This study adds to Modern Portfolio Theory (MPT by providing an additional measure to market beta in constructing a more efficient investment portfolio. The additional measure analyses the volatility spill-over effects among stocks within the same portfolio. Using intraday stock returns from five top-40 listed stocks on the JSE between July 2008 and April 2010, volatility spill-over effects were estimated with a residual- based test (aggregate shock [AS] model framework. It is shown that when a particular stock attracted fewer volatility spill-over effects from the other stocks in the portfolio, the overall portfolio volatility decreased as well. In most cases market beta showcased similar results. Therefore, in order to construct a more efficient risk- adjusted portfolio, one requires both a portfolio that has a unit correlation with the market (beta-based, and stocks that showcase the least amount of volatility spill-over effects amongst one another. These results might assist portfolio managers to construct lower mean variance portfolios.

Biological oceanography of the red oceanic system

Science.gov (United States)

Theil, Hjalmar; Weikert, Horst

1. In 1977, 1979 and 1980-81, investigations were carried out which aimed at evaluating the potential risks from mining metalliferous muds precipating in the Atlantis II Deep of the central Red Sea. This environmental research was initiated by the Saudi Sudanese Red Sea Joint Commission in order to avoid any danger for the Red Sea ecosystem. The broad environmental research programme coherent studies in physical, chemical, biological, and geological oceanography as well as toxicological investigations in the oceanic and in reef zones. We summarise the results from our biological fiels studies in the open sea. 2. The biological investigations were concentrated on the area of the Atlantis II Deep. Benthos was sampled between 700-2000m. For comparison a few samples were also taken further north in the central Red Sea, and to east and west along the flanking deep terraces (500-1000m). Plankton studies covered the total water column above the Deep, and were extended along the axial through to north and south. 3. Benthos sampling was carried out using a heavy closing trawl, a large box grab (box size 50 × 50 cm), Van Veen grabs and traps; photographic surveys were made a phototrap and a photosled. Community respiration was measured with a ship-board method using grab subsamples. Nutrient concentrations, seston and phytoplankton standing stocks as well as in situ primary production were determined from hydrocast samples. Data on zooplankton and micronekton composition and standing stock were obtained from samples collected using different multiple opening-and-closing nets equipped with 100 μm, 300 μm, and 1000 μm mesh sizes. Daily and ontogenetical vertical migration patterns were studied by comparisons of data from midday and midnight tows. 4. Throughout the whole area the sediment is a pteropod ooze containing low contentrations of organic matter; measured organic carbon and nitrogen contents were 0.5 and 0.05% respectively, and chloroplastic pigment equivalents

Physical and biological data collected with CDT, fluorometer, and SeaSoar aboard the ship WECOMA as part of Global Ocean Ecosystem Dynamics (GLOBEC) in the North Pacific Ocean from May 30 to June 16 2000 (NODC Accession 0000986)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Physical and biological data collected with CDT, fluorometer, and SeaSoar aboard the ship WECOMA in the North Pacific Ocean from May 30 to June 16 2000. These data...

Learning to Select Supplier Portfolios for Service Supply Chain.

Science.gov (United States)

Zhang, Rui; Li, Jingfei; Wu, Shaoyu; Meng, Dabin

2016-01-01

The research on service supply chain has attracted more and more focus from both academia and industrial community. In a service supply chain, the selection of supplier portfolio is an important and difficult problem due to the fact that a supplier portfolio may include multiple suppliers from a variety of fields. To address this problem, we propose a novel supplier portfolio selection method based on a well known machine learning approach, i.e., Ranking Neural Network (RankNet). In the proposed method, we regard the problem of supplier portfolio selection as a ranking problem, which integrates a large scale of decision making features into a ranking neural network. Extensive simulation experiments are conducted, which demonstrate the feasibility and effectiveness of the proposed method. The proposed supplier portfolio selection model can be applied in a real corporation easily in the future.

E-Portfolio Web-based for Students’ Internship Program Activities

Science.gov (United States)

Juhana, A.; Abdullah, A. G.; Somantri, M.; Aryadi, S.; Zakaria, D.; Amelia, N.; Arasid, W.

2018-02-01

Internship program is an important part in vocational education process to improve the quality of competent graduates. The complete work documentation process in electronic portfolio (e-Portfolio) platform will facilitate students in reporting the results of their work to both university and industry supervisor. The purpose of this research is to create a more easily accessed e-Portfolio which is appropriate for students and supervisors’ need in documenting their work and monitoring process. The method used in this research is fundamental research. This research is focused on the implementation of internship e-Portfolio features by demonstrating them to students who have conducted internship program. The result of this research is to create a proper web-based e-Portfolio which can be used to facilitate students in documenting the results of their work and aid supervisors in monitoring process during internship.

The impact on atmospheric CO2 of iron fertilization induced changes in the ocean's biological pump

Directory of Open Access Journals (Sweden)

J. C. McWilliams

2008-03-01

Full Text Available Using numerical simulations, we quantify the impact of changes in the ocean's biological pump on the air-sea balance of CO2 by fertilizing a small surface patch in the high-nutrient, low-chlorophyll region of the eastern tropical Pacific with iron. Decade-long fertilization experiments are conducted in a basin-scale, eddy-permitting coupled physical/biogeochemical/ecological model. In contrast to previous studies, we find that most of the dissolved inorganic carbon (DIC removed from the euphotic zone by the enhanced biological export is replaced by uptake of CO2 from the atmosphere. Atmospheric uptake efficiencies, the ratio of the perturbation in air-sea CO2 flux to the perturbation in export flux across 100 m, integrated over 10 years, are 0.75 to 0.93 in our patch size-scale experiments. The atmospheric uptake efficiency is insensitive to the duration of the experiment. The primary factor controlling the atmospheric uptake efficiency is the vertical distribution of the enhanced biological production and export. Iron fertilization at the surface tends to induce production anomalies primarily near the surface, leading to high efficiencies. In contrast, mechanisms that induce deep production anomalies (e.g. altered light availability tend to have a low uptake efficiency, since most of the removed DIC is replaced by lateral and vertical transport and mixing. Despite high atmospheric uptake efficiencies, patch-scale iron fertilization of the ocean's biological pump tends to remove little CO2 from the atmosphere over the decadal timescale considered here.

Multi-objective possibilistic model for portfolio selection with transaction cost

Science.gov (United States)

Jana, P.; Roy, T. K.; Mazumder, S. K.

2009-06-01

In this paper, we introduce the possibilistic mean value and variance of continuous distribution, rather than probability distributions. We propose a multi-objective Portfolio based model and added another entropy objective function to generate a well diversified asset portfolio within optimal asset allocation. For quantifying any potential return and risk, portfolio liquidity is taken into account and a multi-objective non-linear programming model for portfolio rebalancing with transaction cost is proposed. The models are illustrated with numerical examples.

Status of portfolios in undergraduate medical education in the LCME accredited US medical school.

Science.gov (United States)

Chertoff, Jason; Wright, Ashleigh; Novak, Maureen; Fantone, Joseph; Fleming, Amy; Ahmed, Toufeeq; Green, Marianne M; Kalet, Adina; Linsenmeyer, Machelle; Jacobs, Joshua; Dokter, Christina; Zaidi, Zareen

2016-09-01

We sought to investigate the number of US medical schools utilizing portfolios, the format of portfolios, information technology (IT) innovations, purpose of portfolios and their ability to engage faculty and students. A 21-question survey regarding portfolios was sent to the 141 LCME-accredited, US medical schools. The response rate was 50% (71/141); 47% of respondents (33/71) reported that their medical school used portfolios in some form. Of those, 7% reported the use of paper-based portfolios and 76% use electronic portfolios. Forty-five percent reported portfolio use for formative evaluation only; 48% for both formative and summative evaluation, and 3% for summative evaluation alone. Seventy-two percent developed a longitudinal, competency-based portfolio. The most common feature of portfolios was reflective writing (79%). Seventy-three percent allow access to the portfolio off-campus, 58% allow usage of tablets and mobile devices, and 9% involve social media within the portfolio. Eighty percent and 69% agreed that the portfolio engaged students and faculty, respectively. Ninety-seven percent reported that the portfolios used at their institution have room for improvement. While there is significant variation in the purpose and structure of portfolios in the medical schools surveyed, most schools using portfolios reported a high level of engagement with students and faculty.

Portfolio Evaluation Based on Efficient Frontier Superiority Using Center of Gravity

Directory of Open Access Journals (Sweden)

Omar Samat

2010-01-01

Full Text Available Investing in portfolio of assets is the best way to reduce the investment risk. The most desired portfolio can be obtained when investors chose to invest in the portfolios that lay on the portfolio’s efficient frontier. However, the superiorities of the portfolios are difficult to differentiate especially when the efficient frontier curves are overlapping. This paper proposed the portfolio’s efficient frontier center of gravity (CoG and Euclidean distance to identify its superiority. A sample of 49 stocks of large-cap and small-cap were used to construct two hypothetical portfolios and its efficient frontiers. The Euclidean distance showed that the large-cap portfolio is superior and having wider feasible solutions compared to the small-cap portfolio. The results of new tool introduced are consistent with the conventional methods. Here the theoretical and practical implications are provided in light of the findings.

Robust Portfolio Optimization using CAPM Approach

Directory of Open Access Journals (Sweden)

mohsen gharakhani

2013-08-01

Full Text Available In this paper, a new robust model of multi-period portfolio problem has been developed. One of the key concerns in any asset allocation problem is how to cope with uncertainty about future returns. There are some approaches in the literature for this purpose including stochastic programming and robust optimization. Applying these techniques to multi-period portfolio problem may increase the problem size in a way that the resulting model is intractable. In this paper, a novel approach has been proposed to formulate multi-period portfolio problem as an uncertain linear program assuming that asset return follows the single-index factor model. Robust optimization technique has been also used to solve the problem. In order to evaluate the performance of the proposed model, a numerical example has been applied using simulated data.

A ubiquitous reflective e-portfolio architecture.

Science.gov (United States)

Forte, Marcos; de Souza, Wanderley L; da Silva, Roseli F; do Prado, Antonio F; Rodrigues, Jose F

2013-11-01

In nurse and in medicine courses, the use of reflective portfolios as a pedagogical tool is becoming a common practice; in the last years, this practice has gradually migrated from paper-based to electronic-based portfolios. Current approaches for reflective e-portfolios, however, do not widely operate at outdoor sites, where data networks are limited or nonexistent. Considering that many of the activities related to nurse and medicine courses relate to professional practices conducted in such conditions, these network shortcomings restrict the adoption of e-portfolios. The present study describes the requirements specification, design, implementation, and evaluation of the Ubiquitous Reflective E-Portfolio Architecture, a solution proposed to support the development of systems based on mobile and wired access for both online and offline operation. We have implemented a prototype named Professional Practice Module to evaluate the Ubiquitous Reflective E-Portfolio Architecture; the module was based on requirements observed during the professional practice, the paper-based portfolio in use, and related learning meetings in the Medicine Course of a Brazilian University. The evaluation of the system was carried out with a learning group of 2nd year students of the medicine course, who answered to extensive evaluation questionnaires. The prototype proved to be operational in the activities of the professional practice of the Medicine Course object of the study, including homework tasks, patient care, data sharing, and learning meetings. It also demonstrated to be versatile with respect to the availability of the computer network that, many times, was not accessible. Moreover, the students considered the module useful and easy to use, but pointed out difficulties about the keyboard and the display sizes of the netbook devices, and about their operational system. Lastly, most of the students declared preference for the electronic Professional Practice Module in internal

Developing a framework for energy technology portfolio selection

Science.gov (United States)

Davoudpour, Hamid; Ashrafi, Maryam

2012-11-01

Today, the increased consumption of energy in world, in addition to the risk of quick exhaustion of fossil resources, has forced industrial firms and organizations to utilize energy technology portfolio management tools viewed both as a process of diversification of energy sources and optimal use of available energy sources. Furthermore, the rapid development of technologies, their increasing complexity and variety, and market dynamics have made the task of technology portfolio selection difficult. Considering high level of competitiveness, organizations need to strategically allocate their limited resources to the best subset of possible candidates. This paper presents the results of developing a mathematical model for energy technology portfolio selection at a R&D center maximizing support of the organization's strategy and values. The model balances the cost and benefit of the entire portfolio.

On long-only information-based portfolio diversification framework

Science.gov (United States)

Santos, Raphael A.; Takada, Hellinton H.

2014-12-01

Using the concepts from information theory, it is possible to improve the traditional frameworks for long-only asset allocation. In modern portfolio theory, the investor has two basic procedures: the choice of a portfolio that maximizes its risk-adjusted excess return or the mixed allocation between the maximum Sharpe portfolio and the risk-free asset. In the literature, the first procedure was already addressed using information theory. One contribution of this paper is the consideration of the second procedure in the information theory context. The performance of these approaches was compared with three traditional asset allocation methodologies: the Markowitz's mean-variance, the resampled mean-variance and the equally weighted portfolio. Using simulated and real data, the information theory-based methodologies were verified to be more robust when dealing with the estimation errors.

Evaluation of the probabilistic safety assessment portfolio for NSD. Plan of work

International Nuclear Information System (INIS)

Gould, J.

1999-01-01

The aim is to use the research portfolio evaluation protocol developed by HSL to evaluate the Probabilistic Safety Assessment (PSA) portfolio, both to draw conclusions about the PSA portfolio and as a pilot study to show the suitability of the evaluation protocol. The objectives of the work are: (1) To collect sufficient information to carry out a preliminary review of the portfolio; (2) o produce a plan of work detailing the time and costs to carry out a full evaluation of the PSA portfolio; (3) to evaluate the PSA portfolio of research; (4) to produce a report of the evaluation of the PSA portfolio; (5) if necessary, to make changes to the methodology in light of the experience gained in the evaluation of the PSA research portfolio. This report completes objectives 1 and 2. It details the plan of work for the evaluation of the PSA research portfolio. The plan has shown that the evaluation of the PSA research portfolio has many difficulties to overcome. It is suitable as a pilot study to show the suitability of the portfolio evaluation protocol and will provide valuable information that can be used to improve it. The evaluation of the PSA portfolio will require a considerable amount of time and effort to complete. The task analysis has shown it to be of the order of Pound Sterling 25k and to take two months to complete after this preliminary data collection. The plan to evaluate the PSA research portfolio detailed in this report should be carried out and the lessons learned by carrying out this pilot study should be used to improve the evaluation protocol

Long-term portfolio investments: New insight into return and risk

Directory of Open Access Journals (Sweden)

Alexander Abramov

2015-09-01

Emphasis is placed on the need for regular adjustments to long-term investors’ portfolios. As portfolios get older, those investors see a reduction in the returns’ dispersion, while differences in risk between various portfolios increase. This means that to maintain a fixed risk–return ratio for a portfolio as the horizon increases, an investor needs to increase the share of lower-risk financial assets during asset allocation process. This thesis becomes especially relevant in the context of retirement savings management.

The Use of Portfolios in Leadership Education

Science.gov (United States)

Olsen, Paul E.

2009-01-01

This paper discusses the benefits of using student portfolios in undergraduate leadership education at Saint Michael's College. There appears to be a natural link between the use of portfolios as a tool to facilitate and document leadership growth and development. The Business Administration and Accounting Department at Saint Michael's College…

Impact of hydrothermalism on the ocean iron cycle.

Science.gov (United States)

Tagliabue, Alessandro; Resing, Joseph

2016-11-28

As the iron supplied from hydrothermalism is ultimately ventilated in the iron-limited Southern Ocean, it plays an important role in the ocean biological carbon pump. We deploy a set of focused sensitivity experiments with a state of the art global model of the ocean to examine the processes that regulate the lifetime of hydrothermal iron and the role of different ridge systems in governing the hydrothermal impact on the Southern Ocean biological carbon pump. Using GEOTRACES section data, we find that stabilization of hydrothermal iron is important in some, but not all regions. The impact on the Southern Ocean biological carbon pump is dominated by poorly explored southern ridge systems, highlighting the need for future exploration in this region. We find inter-basin differences in the isopycnal layer onto which hydrothermal Fe is supplied between the Atlantic and Pacific basins, which when combined with the inter-basin contrasts in oxidation kinetics suggests a muted influence of Atlantic ridges on the Southern Ocean biological carbon pump. Ultimately, we present a range of processes, operating at distinct scales, that must be better constrained to improve our understanding of how hydrothermalism affects the ocean cycling of iron and carbon.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'. © 2016 The Author(s).

An application of almost marginal conditional stochastic dominance (AMCSD) on forming efficient portfolios

Science.gov (United States)

Slamet, Isnandar; Mardiana Putri Carissa, Siska; Pratiwi, Hasih

2017-10-01

Investors always seek an efficient portfolio which is a portfolio that has a maximum return on specific risk or minimal risk on specific return. Almost marginal conditional stochastic dominance (AMCSD) criteria can be used to form the efficient portfolio. The aim of this research is to apply the AMCSD criteria to form an efficient portfolio of bank shares listed in the LQ-45. This criteria is used when there are areas that do not meet the criteria of marginal conditional stochastic dominance (MCSD). On the other words, this criteria can be derived from quotient of areas that violate the MCSD criteria with the area that violate and not violate the MCSD criteria. Based on the data bank stocks listed on LQ-45, it can be stated that there are 38 efficient portfolios of 420 portfolios where each portfolio comprises of 4 stocks and 315 efficient portfolios of 1710 portfolios with each of portfolio has 3 stocks.

Reinforcement Learning in Repeated Portfolio Decisions

OpenAIRE

Diao, Linan; Rieskamp, Jörg

2011-01-01

How do people make investment decisions when they receive outcome feedback? We examined how well the standard mean-variance model and two reinforcement models predict people's portfolio decisions. The basic reinforcement model predicts a learning process that relies solely on the portfolio's overall return, whereas the proposed extended reinforcement model also takes the risk and covariance of the investments into account. The experimental results illustrate that people reacted sensitively to...

Feature selection for portfolio optimization

DEFF Research Database (Denmark)

Bjerring, Thomas Trier; Ross, Omri; Weissensteiner, Alex

2016-01-01

Most portfolio selection rules based on the sample mean and covariance matrix perform poorly out-of-sample. Moreover, there is a growing body of evidence that such optimization rules are not able to beat simple rules of thumb, such as 1/N. Parameter uncertainty has been identified as one major....... While most of the diversification benefits are preserved, the parameter estimation problem is alleviated. We conduct out-of-sample back-tests to show that in most cases different well-established portfolio selection rules applied on the reduced asset universe are able to improve alpha relative...

CHARACTERISTICS OF INVESTMENT PORTFOLIOS PASSIVE MANAGEMENT STRATEGY ON THE CAPITAL MARKET

Directory of Open Access Journals (Sweden)

MIHAELA SUDACEVSCHI

2013-05-01

Full Text Available The strategies of investment portfolios management on the capital market involves a range of transactions with different financial securities, aimed at optimizing the results. On a developed and efficient capital market, with a high liquidity level, portfolio management primarly depends on investor’s targeted level of return and the risk profile of the investor. Passive strategy of investment portfolios management is applied especially by risk aversion investors, who are taking into account all existing risks in the capital market and seeking to preserve the value of investments, rather than increasing its value. This strategy presume that the investor has no information about the prices and the return of securities that would make him to give to his investment portfolio a different structure from the structure of capital market portfolio. Therefore, he will seek a return level equal to the return on the market portfolio, minimizing the portfolio risk up to eliminating the specific risk.

Capstone Portfolios and Geography Student Learning Outcomes

Science.gov (United States)

Mossa, Joann

2014-01-01

Due to increasing demands regarding student learning outcomes and accreditation, a capstone portfolio was added to assess critical thinking and communication skills of geography majors at a large public university in the USA. The portfolio guidelines were designed to be adaptable to a flexible curriculum where about half of the requirements within…

2010-11 Research Portfolio: Research & Development Division

Science.gov (United States)

Educational Testing Service, 2010

2010-01-01

This document describes the breadth of the research that the ETS (Educational Testing Service) Research & Development division is conducting in 2010. This portfolio will be updated in early 2011 to reflect changes to existing projects and new projects that were added after this document was completed. The research described in this portfolio falls…

Applying Portfolio Theory to EU Electricity Planning and Policy-Making

Energy Technology Data Exchange (ETDEWEB)

Awerbuch, Shimon; Berger, Martin

2003-02-01

This study introduces mean-variance portfolio theory and evaluates its potential application to the development of efficient (optimal) European Union (EU-15) generating portfolios that enhance energy security and diversification objectives. The analysis extends to European countries the previous work done by Awerbuch in the US, and applies a significantly more detailed portfolio model that reflects the risk of the relevant generating cost streams: fuel, operation and maintenance and construction period costs. It illustrates the portfolio effects of different generating mixes. The study offers preliminary findings on the effects of including more renewable energy sources in the typical EU portfolio mix and suggests interesting directions for further study. The study arises from the perception that these standard, finance-oriented analyses may offer valuable enhancements to energy planning, and concepts of energy security and diversity. Clearly the combination of better portfolio construction and more accurate pricing should lead to more optimal decisions in the round. This study, therefore, represents an effort to complement traditional approaches and point researchers and planners into new territory. The results generally indicate that the existing and projected EU generating mixes are sub optimal - though slightly - from a risk-return perspective, which implies that feasible portfolios with lower cost and risk exist. These can be developed by adjusting the conventional mix and by including larger shares of wind or similar renewable technologies. The results of the portfolio analysis suggest that fixed cost technologies such as renewables must be a part of any efficient generating portfolio. Our assessment of all technologies is limited to risk and cost measures, although other benefits, including low externality costs and sustainability, are often cited for renewables.

EFFICIENCY OF CREDIT PORTFOLIO MANAGEMENT IN CONDITIONS OF ECONOMIC INSTABILITY

Directory of Open Access Journals (Sweden)

Koshel H.

2018-01-01

Full Text Available Introduction. The active development of integration processes causes the necessity of applying high-level approaches to management of the banking system, which is an essential part of the financial sector. Due to the importance of credit operations in the portfolio of banking assets, development of efficient and flexible credit management system is the basis for financial and market stability of banks. Purpose. Analyze the condition of the credit portfolio of banking institutions under the influence of economic processes and make conclusions and recommendations about the effectiveness of managing the bank’s credit portfolio and generalize ways of improving the structure and quality of the bank’s credit portfolio. Results. Over the last six years, the quality of the credit portfolio has become worse because of the bad debts growing and, as a result, decreasing in revenues. The calculated coefficient of management efficiency of a credit portfolio shows the dependence of this indicator on the value of risk and yield. In order to confirm the dependence and determine the degree of influence of these indicators on the efficiency of management of a loan portfolio, an economic-mathematical model was constructed on the example of both individual banks and the banking system as a whole. Detected dependence of factors is quite logical, therefore, the model can be recommended for practical use. Conclusion. Using this method of determining the management efficiency of a credit portfolio will allow the management of the bank to make reasonable decisions. It will allow the possibility of forming a more justified credit portfolio, taking into account not only the profitability, but also the real level of risk of credit operations.

Optimal consumption—portfolio problem with CVaR constraints

International Nuclear Information System (INIS)

Zhang, Qingye; Gao, Yan

2016-01-01

The optimal portfolio selection is a fundamental issue in finance, and its two most important ingredients are risk and return. Merton's pioneering work in dynamic portfolio selection emphasized only the expected utility of the consumption and the terminal wealth. To make the optimal portfolio strategy be achievable, risk control over bankruptcy during the investment horizon is an indispensable ingredient. So, in this paper, we consider the consumption-portfolio problem coupled with a dynamic risk control. More specifically, different from the existing literature, we impose a dynamic relative CVaR constraint on it. By the stochastic dynamic programming techniques, we derive the corresponding Hamilton–Jacobi–Bellman (HJB) equation. Moreover, by the Lagrange multiplier method, the closed form solution is provided when the utility function is a logarithmic one. At last, an illustrative empirical study is given. The results show the distinct difference of the portfolio strategies with and without the CVaR constraints: the proportion invested in the risky assets is reduced over time with CVaR constraint instead of being constant without CVaR constraints. This can provide a good decision-making reference for the investors.

Applying Portfolio Selection: A Case of Indonesia Stock Exchange

Directory of Open Access Journals (Sweden)

Maria Praptiningsih

2012-01-01

Full Text Available This study has three objectives. First, we investigate whether Modern Portfolio Theory can be applied on the financial decisions that made by investors or individual in order to increase their wealth through investment activities. Second, we examine the real behavior of each asset in terms of capital assets pricing models. Third, we determine whether our portfolio is the best model to produce a higher return in a given level of risk or a lowest risk in a particular level of return. It is found that three different stocks listed in the Indonesia Stock Exchange have a positive relationship with market returns. The reactions of the investor regarding these stocks are not influenced by each other. Lastly, the minimum variance portfolio (MVP point which represents the single portfolio with the lowest possible level of standard deviation, occurs when the expected return of portfolio is approximately 2.2 percent at a standard deviation of 8.8 percent.

Investment risk management by applying contemporary modern portfolio theory

Directory of Open Access Journals (Sweden)

Jakšić Milena

2015-01-01

Full Text Available Investment risk is the principal threat to the assets side of the balance sheets of financial institutions. It is evident that investors who concentrate their wealth on one type of securities can rarely be found. Instead, they tend to invest diversified portfolio of securities. This reduces the degree of risk of the expected return, which depends both on the absolute risk of each investment in the portfolio, and the relationship that exists between individual investments within the portfolio. The paper analyzes the investment risk management by using modern portfolio theory in both national and global financial f lows. At the same time, the paper considers the risk management models that ensures efficient portfolio diversification, aiming at investment risk reduction. It is pointed out that the investment risk management in modern financial f lows is a complex process, and that the development of financial theory goes towards improving, soft risk management method.

The use of e-portfolio in a linear algebra course

Directory of Open Access Journals (Sweden)

María Isabel García-Planas

2016-03-01

Full Text Available The use of e-portfolio becomes more common learning and student assessment; and this is due to the need for teachers to enhance students’ autonomy. The use of e-portfolio helps students to reflect on their own learning process. Lectures to large groups should not be limited only to classes, but must foster active learning, and in this regard, the introduction of the e-portfolio is a good tool because it stimulates collaborative and cooperative work among students and in turn encourages feedback with the teacher. To apply active methodologies during 2014-15 has been introduced in the course of the preparation of Linear Algebra comprehensive e-portfolio. To prepare the work of the e-portfolio the teacher had to clearly define the objectives that must be achieved by the students, and has had to plan in an understandable manner the tasks that the students can work independently outside the classroom. For the realization of the e-portfolio have been used different platforms. Each third of the students worked with a different platform, through AteneaLabs that it has provided templates in order that each student make their own e-portfolio, as well as it provide all necessary manuals. The platforms used were: Mahara, Exabis, WordPress and Google Sites. Formative assessment of the e-portfolio has been made from different rubrics defined in in the course syllabus and known by students since the beginning of the course.

The returns and risks of investment portfolio in a financial market

Science.gov (United States)

Li, Jiang-Cheng; Mei, Dong-Cheng

2014-07-01

The returns and risks of investment portfolio in a financial system was investigated by constructing a theoretical model based on the Heston model. After the theoretical model and analysis of portfolio were calculated and analyzed, we find the following: (i) The statistical properties (i.e., the probability distribution, the variance and loss rate of equity portfolio return) between simulation results of the theoretical model and the real financial data obtained from Dow Jones Industrial Average are in good agreement; (ii) The maximum dispersion of the investment portfolio is associated with the maximum stability of the equity portfolio return and minimal investment risks; (iii) An increase of the investment period and a worst investment period are associated with a decrease of stability of the equity portfolio return and a maximum investment risk, respectively.

[Portfolio in nursing school: myth or reality].

Science.gov (United States)

Garnier, Chantal; Marchand, Claire

2012-09-01

The portfolio is a new tool that has been introduced for the setting up of a new program concerning the nurse training. It aims at the would-be nurse to improve their self-reliance and make them assess themselves through a critical and reflexive approach. Indeed, the portfolio is mostly made up of sheets that the student has to fill in when describing and analysing several professional conditions. This study is about the assessment of the relevance in the portfolio that each nurse student owns in order to make them improve their reflexive practical. The work will, thus, suggest different ways of thinking and improving the use of the tool. 30 portfolios were chosen randomly among the 2nd year students, because 180 analysis were assessed thanks to a grid. 10 viewpoints from volunteer students were gathered after several semi directive interviews. The qualitative and evaluative analysis shows that the students develop the reflexive practical throughout their trainings. It seems, indeed, relevant to choose the portfolio in order to help the students to develop this way of working. According to them, there are several positive points such as the distance towards an event, an awareness-raising of the acquisition, feedbacks about the quality of the text by the trainer and an ability to assess oneself. Yet, even though it was created 18 months ago, there are some limits such as the too short period of mentoring and feedback, the lack of time for the students to write their analysis, the fact that it is not a practical tool, and the unclear description of assessment criteria. In order to fulfil the needs, some solutions are to be found. The portfolio is clearly helpful for the students who wish to increase/improve gradually their reflexive practice. Thus, the trainer's role is crucial, when he is a supervisor.

An Artificial Bee Colony Algorithm for Uncertain Portfolio Selection

OpenAIRE

Chen, Wei

2014-01-01

Portfolio selection is an important issue for researchers and practitioners. In this paper, under the assumption that security returns are given by experts’ evaluations rather than historical data, we discuss the portfolio adjusting problem which takes transaction costs and diversification degree of portfolio into consideration. Uncertain variables are employed to describe the security returns. In the proposed mean-variance-entropy model, the uncertain mean value of the return is ...

A portfolio evaluation framework for air transportation improvement projects

Science.gov (United States)

Baik, Hyeoncheol

This thesis explores the application of portfolio theory to the Air Transportation System (ATS) improvement. The ATS relies on complexly related resources and different stakeholder groups. Moreover, demand for air travel is significantly increasing relative to capacity of air transportation. In this environment, improving the ATS is challenging. Many projects, which are defined as technologies or initiatives, for improvement have been proposed and some have been demonstrated in practice. However, there is no clear understanding of how well these projects work in different conditions nor of how they interact with each other or with existing systems. These limitations make it difficult to develop good project combinations, or portfolios that maximize improvement. To help address this gap, a framework for identifying good portfolios is proposed. The framework can be applied to individual projects or portfolios of projects. Projects or portfolios are evaluated using four different groups of factors (effectiveness, time-to-implement, scope of applicability, and stakeholder impacts). Portfolios are also evaluated in terms of interaction-determining factors (prerequisites, co-requisites, limiting factors, and amplifying factors) because, while a given project might work well in isolation, interdependencies between projects or with existing systems could result in lower overall performance in combination. Ways to communicate a portfolio to decision makers are also introduced. The framework is unique because (1) it allows using a variety of available data, and (2) it covers diverse benefit metrics. For demonstrating the framework, an application to ground delay management projects serves as a case study. The portfolio evaluation approach introduced in this thesis can aid decision makers and researchers at universities and aviation agencies such as Federal Aviation Administration (FAA), National Aeronautics and Space Administration (NASA), and Department of Defense (DoD), in

Transparency in the ePortfolio Creation Process

Science.gov (United States)

Jones, Stephanie A.; Downs, Elizabeth; Jenkins, Stephen J.

2015-01-01

This paper presents the findings of a study examining the effect of transparency on the ePortfolio creation process. The purpose of the study was to examine whether increased awareness of other students' ePortfolios through the implementation of transparency and peer review would positively affect the quality of performance of school library media…

Using ePortfolios to Encourage Responsible Feedback

Science.gov (United States)

Morales, Lucia; Soler-Dominguez, Amparo

2015-01-01

This article aims to look at the value that ePortfolios can add to business studies, specifically in the financial field. In order to answer the question, "Do ePortfolios contribute to the development and enhancement of responsible feedback in the classroom?", the study analyzed the work done by postgraduate students pursuing a Master's…

Portfolio management of hydropower producer via stochastic programming

International Nuclear Information System (INIS)

Liu, Hongling; Jiang, Chuanwen; Zhang, Yan

2009-01-01

This paper presents a stochastic linear programming framework for the hydropower portfolio management problem with uncertainty in market prices and inflows on medium term. The uncertainty is modeled as a scenario tree using the Monte Carlo simulation method, and the objective is to maximize the expected revenue over the entire scenario tree. The portfolio decisions of the stochastic model are formulated as a tradeoff involving different scenarios. Numerical results illustrate the impact of uncertainty on the portfolio management decisions, and indicate the significant value of stochastic solution. (author)

Multiperiod Mean-Variance Portfolio Optimization via Market Cloning

International Nuclear Information System (INIS)

Ankirchner, Stefan; Dermoune, Azzouz

2011-01-01

The problem of finding the mean variance optimal portfolio in a multiperiod model can not be solved directly by means of dynamic programming. In order to find a solution we therefore first introduce independent market clones having the same distributional properties as the original market, and we replace the portfolio mean and variance by their empirical counterparts. We then use dynamic programming to derive portfolios maximizing a weighted sum of the empirical mean and variance. By letting the number of market clones converge to infinity we are able to solve the original mean variance problem.

Multiperiod Mean-Variance Portfolio Optimization via Market Cloning

Energy Technology Data Exchange (ETDEWEB)

Ankirchner, Stefan, E-mail: ankirchner@hcm.uni-bonn.de [Rheinische Friedrich-Wilhelms-Universitaet Bonn, Institut fuer Angewandte Mathematik, Hausdorff Center for Mathematics (Germany); Dermoune, Azzouz, E-mail: Azzouz.Dermoune@math.univ-lille1.fr [Universite des Sciences et Technologies de Lille, Laboratoire Paul Painleve UMR CNRS 8524 (France)

2011-08-15

The problem of finding the mean variance optimal portfolio in a multiperiod model can not be solved directly by means of dynamic programming. In order to find a solution we therefore first introduce independent market clones having the same distributional properties as the original market, and we replace the portfolio mean and variance by their empirical counterparts. We then use dynamic programming to derive portfolios maximizing a weighted sum of the empirical mean and variance. By letting the number of market clones converge to infinity we are able to solve the original mean variance problem.

Acreage portfolio management

International Nuclear Information System (INIS)

Schneider, Georges

1994-01-01

This chapter demonstrates the need for acreage portfolio management at the stage of maturity which has been reached in the UK sector of the North Sea petroleum industry. It outlines the goals, the main features of the deals and the business process. (UK)

Towards a reference model for portfolio management for product development

DEFF Research Database (Denmark)

Larsson, Flemming

2006-01-01

The aim of this paper is to explore the concept of portfolio management for product development at company level. Departing from a combination of explorative interviews with industry professionals and a literature review a proposal for a reference model for portfolio management is developed....... The model consists of a set of defined and interrelated concepts which forms a coherent and consistent reference model that explicate the totality of the portfolio management concept at company level in terms of structure, processes and elements. The model simultaneously pinpoints, positions and integrates...... several central dimensions of portfolio management....

Subjective Life Horizon and Portfolio Choice

OpenAIRE

Spaenjers , Christophe; Spira, Sven Michael

2013-01-01

Using data from a U.S. household survey, we examine the empirical relation between subjective life horizon (i.e., the self-reported expectation of remaining life span) and portfolio choice. We find that equity portfolio shares are higher for investors with longer horizons, ceteris paribus, in line with theoretical predictions. This result is robust to controlling for optimism and health status, accounting for the endogeneity of equity market participation, or instrumenting subjective life hor...

Quantifying the role of personal management style in the success of investment portfolios

Directory of Open Access Journals (Sweden)

E.A. Wagenaar

2014-01-01

Full Text Available It is extremely difficult to quantify the effect of different management styles of portfolio managers upon the success of their portfolios. Various mathematical models in the literature attempt to predict the risk and returns of portfolios according to changes in the economic arena, but these models usually do not take into account the personal styles of portfolio managers. The aim of this paper is a modest attempt at quantifying the effect of different managerial styles upon decisions regarding portfolios. This is accomplished by the formulation of a mathematical performance index that portrays the influence of a portfolio manager's personal and managerial characteristics on the success of his portfolio.

Alternative Investments: Valuation of Wine as a Means for Portfolio Diversification

Directory of Open Access Journals (Sweden)

Daiva Jurevičienė

2015-03-01

Full Text Available This article analyses wine as an alternative investment tool and its relevance for investment portfolio diversification. Advantages and disadvantages of alternatives, benefits and weakness and peculiarities of investing in wine are systemised. In addition, the article looks at statistical data analysis of fine wine market and compares wine with other investment tools. The examination is based on three investment instruments: US equities (using S&P 500 index, bonds (using US 20-Year treasury constant maturity rate/DGS20 and wine (based on Fine Wine Investable index using 1993–2012 (end of year data. The investment portfolios made with two and three above-mentioned investment tools basing on H. Markowitz’s investment portfolio theory and effective curves are presented. It was found that return on investments only from equities and bonds or wine and one of these traditional instruments are signally less than from the investment mix of all three tools. Furthermore, portfolios made only from equities and bonds provide the lowest return compared to others. Choosing from two investments portfolios, results of bond/wine portfolios propose higher return with the same risk level compared to equities/wine portfolio. Consequently, despite some slowdown of wine index during financial crises, wine relevance for portfolio diversification in post crises period was proved.

Choosing an Optimal e-Portfolio System for the Institution

OpenAIRE

YAMAMOTO, Toshiyuki

2010-01-01

Implementing an e-Portfolio system to enhance educational processes and outcomes has been becoming a hot issue among the Japanese universities that are ambitious in resetting their mission statements. In such universities, defining purposes, clearly stating what to be focused, learning processes, and expected outcomes are the critical issues in the development of their original e-Portfolio system. However, not all institutions are aware that e-Portfolio has advantages and disadvantages. One o...

Portfolio Diversification in the South-East European Equity Markets

OpenAIRE

Zaimovic Azra; Arnaut-Berilo Almira; Mustafic Arnela

2017-01-01

Diversification potential enables investors to manage their risk and decrease risk exposure. Good diversification policy is a safety net that prevents a portfolio from losing its value. A well-diversified portfolio consists of different categories of property with low correlations, while highly correlated markets have the feature of low possibilities for diversification. The biggest riddle in the world of investments is to find the optimal portfolio within a set of available assets with limit...

[Development of a portfolio for competency-based assessment in a clinical clerkship curriculum].

Science.gov (United States)

Roh, HyeRin; Lee, Jong-Tae; Yoon, Yoo Sang; Rhee, Byoung Doo

2015-12-01

The purpose of this report was to describe our experience in planning and developing a portfolio for a clinical clerkship curriculum. We have developed a portfolio for assessing student competency since 2007. During an annual workshop on clinical clerkship curricula, clerkship directors from five Paik hospitals of Inje University met to improve the assessment of the portfolio. We generated templates for students to record their activities and reflection and receive feedback. We uploaded these templates to our school's website for students to download freely. Annually, we have held a faculty development seminar and a workshop for portfolio assessment and feedback. Also, we established an orientation program on how to construct a learning portfolio for students. Future actions include creating a ubiquitous portfolio system, extending the portfolio to the entire curriculum, setting up an advisor system, and managing the quality of the portfolio. This study could be helpful for medical schools that plan to improve their portfolio assessment with an outcome-based approach.

Development of an Electronic Portfolio System Success Model: An Information Systems Approach

Science.gov (United States)

Balaban, Igor; Mu, Enrique; Divjak, Blazenka

2013-01-01

This research has two main goals: to develop an instrument for assessing Electronic Portfolio (ePortfolio) success and to build a corresponding ePortfolio success model using DeLone and McLean's information systems success model as the theoretical framework. For this purpose, we developed an ePortfolio success measurement instrument and structural…

The influence of the ocean circulation state on ocean carbon storage and CO2 drawdown potential in an Earth system model

Science.gov (United States)

Ödalen, Malin; Nycander, Jonas; Oliver, Kevin I. C.; Brodeau, Laurent; Ridgwell, Andy

2018-03-01

During the four most recent glacial cycles, atmospheric CO2 during glacial maxima has been lowered by about 90-100 ppm with respect to interglacials. There is widespread consensus that most of this carbon was partitioned in the ocean. It is, however, still debated which processes were dominant in achieving this increased carbon storage. In this paper, we use an Earth system model of intermediate complexity to explore the sensitivity of ocean carbon storage to ocean circulation state. We carry out a set of simulations in which we run the model to pre-industrial equilibrium, but in which we achieve different states of ocean circulation by changing forcing parameters such as wind stress, ocean diffusivity and atmospheric heat diffusivity. As a consequence, the ensemble members also have different ocean carbon reservoirs, global ocean average temperatures, biological pump efficiencies and conditions for air-sea CO2 disequilibrium. We analyse changes in total ocean carbon storage and separate it into contributions by the solubility pump, the biological pump and the CO2 disequilibrium component. We also relate these contributions to differences in the strength of the ocean overturning circulation. Depending on which ocean forcing parameter is tuned, the origin of the change in carbon storage is different. When wind stress or ocean diapycnal diffusivity is changed, the response of the biological pump gives the most important effect on ocean carbon storage, whereas when atmospheric heat diffusivity or ocean isopycnal diffusivity is changed, the solubility pump and the disequilibrium component are also important and sometimes dominant. Despite this complexity, we obtain a negative linear relationship between total ocean carbon and the combined strength of the northern and southern overturning cells. This relationship is robust to different reservoirs dominating the response to different forcing mechanisms. Finally, we conduct a drawdown experiment in which we investigate

The influence of the ocean circulation state on ocean carbon storage and CO2 drawdown potential in an Earth system model

Directory of Open Access Journals (Sweden)

M. Ödalen

2018-03-01

Full Text Available During the four most recent glacial cycles, atmospheric CO2 during glacial maxima has been lowered by about 90–100 ppm with respect to interglacials. There is widespread consensus that most of this carbon was partitioned in the ocean. It is, however, still debated which processes were dominant in achieving this increased carbon storage. In this paper, we use an Earth system model of intermediate complexity to explore the sensitivity of ocean carbon storage to ocean circulation state. We carry out a set of simulations in which we run the model to pre-industrial equilibrium, but in which we achieve different states of ocean circulation by changing forcing parameters such as wind stress, ocean diffusivity and atmospheric heat diffusivity. As a consequence, the ensemble members also have different ocean carbon reservoirs, global ocean average temperatures, biological pump efficiencies and conditions for air–sea CO2 disequilibrium. We analyse changes in total ocean carbon storage and separate it into contributions by the solubility pump, the biological pump and the CO2 disequilibrium component. We also relate these contributions to differences in the strength of the ocean overturning circulation. Depending on which ocean forcing parameter is tuned, the origin of the change in carbon storage is different. When wind stress or ocean diapycnal diffusivity is changed, the response of the biological pump gives the most important effect on ocean carbon storage, whereas when atmospheric heat diffusivity or ocean isopycnal diffusivity is changed, the solubility pump and the disequilibrium component are also important and sometimes dominant. Despite this complexity, we obtain a negative linear relationship between total ocean carbon and the combined strength of the northern and southern overturning cells. This relationship is robust to different reservoirs dominating the response to different forcing mechanisms. Finally, we conduct a drawdown experiment

Aircraft technology portfolio optimization using ant colony optimization

Science.gov (United States)

Villeneuve, Frederic J.; Mavris, Dimitri N.

2012-11-01

Technology portfolio selection is a combinatorial optimization problem often faced with a large number of combinations and technology incompatibilities. The main research question addressed in this article is to determine if Ant Colony Optimization (ACO) is better suited than Genetic Algorithms (GAs) and Simulated Annealing (SA) for technology portfolio optimization when incompatibility constraints between technologies are present. Convergence rate, capability to find optima, and efficiency in handling of incompatibilities are the three criteria of comparison. The application problem consists of finding the best technology portfolio from 29 aircraft technologies. The results show that ACO and GAs converge faster and find optima more easily than SA, and that ACO can optimize portfolios with technology incompatibilities without using penalty functions. This latter finding paves the way for more use of ACO when the number of constraints increases, such as in the technology and concept selection for complex engineering systems.

Decomposing the effects of ocean warming on chlorophyll a concentrations into physically and biologically driven contributions

International Nuclear Information System (INIS)

Olonscheck, D; Hofmann, M; Schellnhuber, H J; Worm, B

2013-01-01

Recently compiled observational data suggest a substantial decline in the global median chlorophyll a concentration over the 20th century, a trend that appears to be linked to ocean warming. Several modelling studies have considered changes in the ocean’s physical structure as a possible cause, while experimental work supports a biological mechanism, namely an observed increase in zooplankton grazing rate that outpaces phytoplankton production at higher temperatures. Here, we present transient simulations derived from a coupled ocean general circulation and carbon cycle model forced by atmospheric fields under unabated anthropogenic global warming (IPCC SRES A1FI scenario). The simulations account for both physical and biological mechanisms, and can reproduce about one quarter of the observed chlorophyll a decline during the 20th century, when using realistically parameterized temperature sensitivity of zooplankton metabolism (Q 10 between 2 and 4) and phytoplankton growth (Q 10 ∼ 1.9). Therefore, we have employed and re-calibrated the standard ecosystem model which assumes a lower temperature sensitivity of zooplankton grazing (Q 10 = 1.1049) by re-scaling phytoplankton growth rates and zooplankton grazing rates. Our model projects a global chlorophyll a decline of >50% by the end of the 21st century. While phytoplankton abundance and chlorophyll a experience pronounced negative effects, primary production and zooplankton concentrations are less sensitive to ocean warming. Although changes in physical structure play an important role, much of the simulated change in chlorophyll a and productivity is related to the uneven temperature sensitivity of the marine ecosystem. (letter)

Portfolios and the market geometry

Science.gov (United States)

Eleutério, Samuel; Araújo, Tanya; Vilela Mendes, R.

2014-09-01

A geometric analysis of return time series, performed in the past, implied that most of the systematic information in the market is contained in a space of small dimension. Here we have explored subspaces of this space to find out the relative performance of portfolios formed from companies that have the largest projections in each one of the subspaces. As expected, it was found that the best performance portfolios are associated with some of the small eigenvalue subspaces and not to the dominant dimensions. This is found to occur in a systematic fashion over an extended period (1990-2008).

Using Facebook-Based e-Portfolio in ESL Writing Classrooms: Impact and Challenges

Science.gov (United States)

Barrot, Jessie S.

2016-01-01

In English as a second language (ESL) writing pedagogy, much attention has been given to electronic portfolio (e-portfolio) assessment via social networking sites. However, little is known about how Facebook can be used as an e-portfolio platform. Hence, this paper describes the impact of Facebook-based e-portfolio on ESL students' writing…

A risk-return based model to measure the performance of portfolio management

Directory of Open Access Journals (Sweden)

Hamid Reza Vakili Fard

2014-10-01

Full Text Available The primary concern in all portfolio management systems is to find a good tradeoff between risk and expected return and a good balance between accepted risk and actual return indicates the performance of a particular portfolio. This paper develops “A-Y Model” to measure the performance of a portfolio and analyze it during the bull and the bear market. This paper considers the daily information of one year before and one year after Iran's 2013 precedential election. The proposed model of this paper provides lost profit and unrealized loss to measure the portfolio performance. The proposed study first ranks the resulted data and then uses some non-parametric methods to see whether there is any change because of the changes in markets on the performance of the portfolio. The results indicate that despite increasing profitable opportunities in bull market, the performance of the portfolio did not match the target risk. As a result, using A-Y Model as a risk and return base model to measure portfolio management's performance appears to reduce risks and increases return of portfolio.

Fifteen years of portfolio assessment of dental hygiene student competency: lessons learned.

Science.gov (United States)

Gadbury-Amyot, Cynthia C; Bray, Kimberly Krust; Austin, Kylie J

2014-10-01

Adoption of portfolio assessment in the educational environment is gaining attention as a means to incorporate self-assessment into the curriculum and to use evidence to support learning outcomes and to demonstrate competency. Portfolios provide a medium for students to demonstrate and document their personal and professional growth across the curriculum. The purpose of this literature review is to discuss the drivers for portfolio education, the benefits to both students and program faculty/administrators, the barriers associated with portfolio use, and suggested solutions that have been determined through several years of "lessons learned." The University of Missouri Kansas City School of Dentistry, Division of Dental Hygiene department has been utilizing portfolio assessment for over 15 years and has collected data related to portfolio performance since 2001. Results from correlational statistics calculated on the 312 dental hygiene students that graduated from 2001 to 2013 demonstrate a positive and significant relationship between portfolio performance and overall GPA as well as portfolio performance and NBDHE scores. Copyright © 2014 The American Dental Hygienists’ Association.

Portfolio management: Finding growth opportunities in a restructured electricity marketplace. Final report

International Nuclear Information System (INIS)

Staley, J.; Patterson, A.; Gardner, T.

1997-12-01

Energy services companies are rapidly creating a wide array of new products and services for their customers. To penetrate the marketplace most effectively, however, these new offerings should be integrated into cohesive portfolios that meet the needs of key customer segments. This report explores the techniques of portfolio management and describes how this tool can help bring greater balance and focus to an energy provider's product and service portfolios. Portfolio management provides a process for initiating, overseeing, and exiting from diverse investments on the basis of not only the merits of each individual investment, but also the merits of those investments in combination. The principles of portfolio management can be applied to various types of investments, including those involving lines of business, new product initiatives, and project commitments. With the rapid transition to a more competitive environment, these types of market-oriented investments are receiving greater scrutiny in the energy services industry. Accordingly, portfolio management techniques are becoming increasingly important business tools. The project team considers three different categories of portfolio management within the context of the energy services industry. Passive portfolio management focuses on choosing the combination of products/services that will provide the most favorable trade-off of risk and return for a given risk tolerance. Balanced portfolio management provides a more aggressive set of techniques that look broadly at a company's multiple objectives and assist in deploying resources to achieve balance along multiple dimensions. Strategic portfolio management goes even further by helping to define a set of synergistic offerings that reinforce one another and the company's strategic direction. In this report the team also documents case studies of companies that profited from their portfolio management efforts and presents a project design for developing and

Seismic and Biological Sources of Ambient Ocean Sound

Science.gov (United States)

Freeman, Simon Eric

Sound is the most efficient radiation in the ocean. Sounds of seismic and biological origin contain information regarding the underlying processes that created them. A single hydrophone records summary time-frequency information from the volume within acoustic range. Beamforming using a hydrophone array additionally produces azimuthal estimates of sound sources. A two-dimensional array and acoustic focusing produce an unambiguous two-dimensional `image' of sources. This dissertation describes the application of these techniques in three cases. The first utilizes hydrophone arrays to investigate T-phases (water-borne seismic waves) in the Philippine Sea. Ninety T-phases were recorded over a 12-day period, implying a greater number of seismic events occur than are detected by terrestrial seismic monitoring in the region. Observation of an azimuthally migrating T-phase suggests that reverberation of such sounds from bathymetric features can occur over megameter scales. In the second case, single hydrophone recordings from coral reefs in the Line Islands archipelago reveal that local ambient reef sound is spectrally similar to sounds produced by small, hard-shelled benthic invertebrates in captivity. Time-lapse photography of the reef reveals an increase in benthic invertebrate activity at sundown, consistent with an increase in sound level. The dominant acoustic phenomenon on these reefs may thus originate from the interaction between a large number of small invertebrates and the substrate. Such sounds could be used to take census of hard-shelled benthic invertebrates that are otherwise extremely difficult to survey. A two-dimensional `map' of sound production over a coral reef in the Hawaiian Islands was obtained using two-dimensional hydrophone array in the third case. Heterogeneously distributed bio-acoustic sources were generally co-located with rocky reef areas. Acoustically dominant snapping shrimp were largely restricted to one location within the area surveyed

International Diversification Versus Domestic Diversification: Mean-Variance Portfolio Optimization and Stochastic Dominance Approaches

Directory of Open Access Journals (Sweden)

Fathi Abid

2014-05-01

Full Text Available This paper applies the mean-variance portfolio optimization (PO approach and the stochastic dominance (SD test to examine preferences for international diversification versus domestic diversification from American investors’ viewpoints. Our PO results imply that the domestic diversification strategy dominates the international diversification strategy at a lower risk level and the reverse is true at a higher risk level. Our SD analysis shows that there is no arbitrage opportunity between international and domestic stock markets; domestically diversified portfolios with smaller risk dominate internationally diversified portfolios with larger risk and vice versa; and at the same risk level, there is no difference between the domestically and internationally diversified portfolios. Nonetheless, we cannot find any domestically diversified portfolios that stochastically dominate all internationally diversified portfolios, but we find some internationally diversified portfolios with small risk that dominate all the domestically diversified portfolios.

Twelve tips for creating an academic teaching portfolio.

Science.gov (United States)

Little-Wienert, Kim; Mazziotti, Mark

2018-01-01

An academic teaching portfolio is not only a requirement at many academic teaching institutions, but it is also important in a medical educator's growth and development through documentation, reflection, evaluation, and change. Creating an academic portfolio may appear daunting at first but with careful advanced preparation, organized evidence collection of your educational work, proof of scholarship, and thorough documentation of self-reflection and change, you can produce a successful product that accurately represents your educational beliefs, accomplishments, and growth throughout your career. This article provides medical educators with twelve steps for creating a successful academic teaching portfolio.

Current industrial practice of managing risks in product development project portfolios

DEFF Research Database (Denmark)

Weng, R.; Oehmen, Josef; Ben-Daya, M.

2013-01-01

Managing portfolios of development and engineering projects currently presents significant challenges to companies. This is even more the case in the management of portfolio risks, where both industry and academia currently lack a clear conceptual understanding of what portfolio risks are and what...

Markowitz portfolio optimization model employing fuzzy measure

Science.gov (United States)

Ramli, Suhailywati; Jaaman, Saiful Hafizah

2017-04-01

Markowitz in 1952 introduced the mean-variance methodology for the portfolio selection problems. His pioneering research has shaped the portfolio risk-return model and become one of the most important research fields in modern finance. This paper extends the classical Markowitz's mean-variance portfolio selection model applying the fuzzy measure to determine the risk and return. In this paper, we apply the original mean-variance model as a benchmark, fuzzy mean-variance model with fuzzy return and the model with return are modeled by specific types of fuzzy number for comparison. The model with fuzzy approach gives better performance as compared to the mean-variance approach. The numerical examples are included to illustrate these models by employing Malaysian share market data.

Extended Information Ratio for Portfolio Optimization Using Simulated Annealing with Constrained Neighborhood

Science.gov (United States)

Orito, Yukiko; Yamamoto, Hisashi; Tsujimura, Yasuhiro; Kambayashi, Yasushi

The portfolio optimizations are to determine the proportion-weighted combination in the portfolio in order to achieve investment targets. This optimization is one of the multi-dimensional combinatorial optimizations and it is difficult for the portfolio constructed in the past period to keep its performance in the future period. In order to keep the good performances of portfolios, we propose the extended information ratio as an objective function, using the information ratio, beta, prime beta, or correlation coefficient in this paper. We apply the simulated annealing (SA) to optimize the portfolio employing the proposed ratio. For the SA, we make the neighbor by the operation that changes the structure of the weights in the portfolio. In the numerical experiments, we show that our portfolios keep the good performances when the market trend of the future period becomes different from that of the past period.

Portfolio careers for medical graduates: implications for postgraduate training and workforce planning.

Science.gov (United States)

Eyre, Harris A; Mitchell, Rob D; Milford, Will; Vaswani, Nitin; Moylan, Steven

2014-06-01

Portfolio careers in medicine can be defined as significant involvement in one or more portfolios of activity beyond a practitioner's primary clinical role, either concurrently or in sequence. Portfolio occupations may include medical education, research, administration, legal medicine, the arts, engineering, business and consulting, leadership, politics and entrepreneurship. Despite significant interest among junior doctors, portfolios are poorly integrated with prevocational and speciality training programs in Australia. The present paper seeks to explore this issue. More formal systems for portfolio careers in Australia have the potential to increase job satisfaction, flexibility and retention, as well as diversify trainee skill sets. Although there are numerous benefits from involvement in portfolio careers, there are also risks to the trainee, employing health service and workforce modelling. Formalising pathways to portfolio careers relies on assessing stakeholder interest, enhancing flexibility in training programs, developing support programs, mentorship and coaching schemes and improving support structures in health services.

Linear versus quadratic portfolio optimization model with transaction cost

Science.gov (United States)

Razak, Norhidayah Bt Ab; Kamil, Karmila Hanim; Elias, Siti Masitah

2014-06-01

Optimization model is introduced to become one of the decision making tools in investment. Hence, it is always a big challenge for investors to select the best model that could fulfill their goal in investment with respect to risk and return. In this paper we aims to discuss and compare the portfolio allocation and performance generated by quadratic and linear portfolio optimization models namely of Markowitz and Maximin model respectively. The application of these models has been proven to be significant and popular among others. However transaction cost has been debated as one of the important aspects that should be considered for portfolio reallocation as portfolio return could be significantly reduced when transaction cost is taken into consideration. Therefore, recognizing the importance to consider transaction cost value when calculating portfolio' return, we formulate this paper by using data from Shariah compliant securities listed in Bursa Malaysia. It is expected that, results from this paper will effectively justify the advantage of one model to another and shed some lights in quest to find the best decision making tools in investment for individual investors.

An unbalanced portfolio.

Science.gov (United States)

Federsel, Hans-Jurgen

2009-06-01

An excellent demonstration of how meaningful and valuable conferences devoted to the topic of project and portfolio management in the pharmaceutical industry can be, was given at an event organized in Barcelona, September 2008. Thus, over this 2-day meeting the delegates were updated on the state of the art in this wide-reaching area from speakers representing an array of companies; from small, relatively new players, via mid-sized, to established large and big pharmas. One common theme that emerged was the importance of assessing the value of drug projects as correctly as possible, especially under the current financial climate and the many challenges facing the industry. Furthermore, experiences from constructing portfolios with the aim to minimize risk and maximize return on investment were shared alongside mathematical approaches to obtain the data required for this purpose and accounts of the pleasures and hardships working in a global context and in partnership constellations. Copyright 2009 Prous Science, S.A.U. or its licensors. All rights reserved.

Portfolio i et lærings- og uddannelsesperspektiv

DEFF Research Database (Denmark)

adjunktpædagogikum og underviserkvalificeringsforløb ved andre uddannelser. Af Lone Krogh Indførelse af portfolio som pædagogisk redskab og som struktur for dokumentation af kompetence i kandidatuddannelse - potentialer og udfordringer. Af Annette Lorentsen og Birthe Lund. Et organisatorisk perspektiv på portfolio...

Electricity portfolio management : optimal peak/off-peak allocations

NARCIS (Netherlands)

Huisman, R.; Mahieu, R.J.; Schlichter, F.

2009-01-01

Electricity purchasers manage a portfolio of contracts in order to purchase the expected future electricity consumption profile of a company or a pool of clients. This paper proposes a mean-variance framework to address the concept of structuring the portfolio and focuses on how to optimally

Electricity Portfolio Management: Optimal Peak / Off-Peak Allocations

NARCIS (Netherlands)

R. Huisman (Ronald); R.J. Mahieu (Ronald); F. Schlichter (Felix)

2007-01-01

textabstractElectricity purchasers manage a portfolio of contracts in order to purchase the expected future electricity consumption profile of a company or a pool of clients. This paper proposes a mean-variance framework to address the concept of structuring the portfolio and focuses on how to

Random Matrix Theory Approach to Indonesia Energy Portfolio Analysis

Science.gov (United States)

Mahardhika, Alifian; Purqon, Acep

2017-07-01

In a few years, Indonesia experienced difficulties in maintaining energy security, the problem is the decline in oil production from 1.6 million barrels per day to 861 thousand barrels per day in 2012. However, there is a difference condition in 2015 until the third week in 2016, world oil prices actually fell at the lowest price level since last 12 years. The decline in oil prices due to oversupply of oil by oil-producing countries of the world due to the instability of the world economy. Wave of layoffs in Indonesia is a response to the decline in oil prices, this led to the energy and mines portfolios Indonesia feared would not be more advantageous than the portfolio in other countries. In this research, portfolio analysis will be done on energy and mining in Indonesia by using stock price data of energy and mines in the period 26 November 2010 until April 1, 2016. It was found that the results have a wide effect of the market potential is high in the determination of the return on the portfolio energy and mines. Later, it was found that there are eight of the thirty stocks in the energy and mining portfolio of Indonesia which have a high probability of return relative to the average return of stocks in a portfolio of energy and mines.

Mean-Coherent Risk and Mean-Variance Approaches in Portfolio Selection : An Empirical Comparison

NARCIS (Netherlands)

Polbennikov, S.Y.; Melenberg, B.

2005-01-01

We empirically analyze the implementation of coherent risk measures in portfolio selection.First, we compare optimal portfolios obtained through mean-coherent risk optimization with corresponding mean-variance portfolios.We find that, even for a typical portfolio of equities, the outcomes can be

Optimal annuity portfolio under inflation risk

DEFF Research Database (Denmark)

Konicz, Agnieszka Karolina; Pisinger, David; Weissensteiner, Alex

2015-01-01

The paper investigates the importance of in ation-linked annuities to individuals facing in ation risk. Given the investment opportunities in nominal, real, and variable annuities, as well as cash and stocks, we investigate the consumption and investment decisions under two different objective fu...... and risk aversion, real annuities are a crucial asset in every portfolio. In addition, without investing in real annuities, the retiree has to rebalance the portfolio more frequently, and still obtains the lower and more volatile real consumption....

Slow science: the value of long ocean biogeochemistry records.

Science.gov (United States)

Henson, Stephanie A

2014-09-28

Sustained observations (SOs) have provided invaluable information on the ocean's biology and biogeochemistry for over 50 years. They continue to play a vital role in elucidating the functioning of the marine ecosystem, particularly in the light of ongoing climate change. Repeated, consistent observations have provided the opportunity to resolve temporal and/or spatial variability in ocean biogeochemistry, which has driven exploration of the factors controlling biological parameters and processes. Here, I highlight some of the key breakthroughs in biological oceanography that have been enabled by SOs, which include areas such as trophic dynamics, understanding variability, improved biogeochemical models and the role of ocean biology in the global carbon cycle. In the near future, SOs are poised to make progress on several fronts, including detecting climate change effects on ocean biogeochemistry, high-resolution observations of physical-biological interactions and greater observational capability in both the mesopelagic zone and harsh environments, such as the Arctic. We are now entering a new era for biological SOs, one in which our motivations have evolved from the need to acquire basic understanding of the ocean's state and variability, to a need to understand ocean biogeochemistry in the context of increasing pressure in the form of climate change, overfishing and eutrophication.

Household Portfolios and Risk Bearing over Age and Time

OpenAIRE

Alessandro Bucciol; Raffaele Miniaci

2011-01-01

We exploit the US Survey of Consumer Finances from 1998 to 2007 to study households’ portfolio risk bearing. We compare four alternative measures of risk, two based on a financial portfolio and two based on a broader portfolio also including – as illiquid assets – human capital, real estate, business wealth and related debt. The measures provide a different ranking of household risk bearing, but they consistently show that risk bearing fell after 2001, and it positively correlates with wealth...

Using the Teaching Portfolio to Anticipate Programmatic Assessment

Science.gov (United States)

Price, Kenneth R.

2013-01-01

Portfolios have long been a staple in professional writing courses: both in employment materials assignments and in entire classes that ask students to reflect on their experiential learning. Portfolios may also be used effectively in business communication teaching methods courses. This article details the justification and methodology for having…

Digital Portfolios: Powerful Marketing Tool for Communications Students

Science.gov (United States)

Nikirk, Martin

2008-01-01

A digital portfolio is a powerful marketing tool for young people searching for employment in the communication or interactive media fields. With a digital portfolio, students can demonstrate their skills at working with software tools, demonstrate appropriate use of materials, explain technical procedures, show an understanding of processes and…

A Bicriteria Approach Identifying Nondominated Portfolios

Directory of Open Access Journals (Sweden)

Javier Pereira

2014-01-01

Full Text Available We explore a portfolio constructive model, formulated in terms of satisfaction of a given set of technical requirements, with the minimum number of projects and minimum redundancy. An algorithm issued from robust portfolio modeling is adapted to a vector model, modifying the dominance condition as convenient, in order to find the set of nondominated portfolios, as solutions of a bicriteria integer linear programming problem. In order to improve the former algorithm, a process finding an optimal solution of a monocriteria version of this problem is proposed, which is further used as a first feasible solution aiding to find nondominated solutions more rapidly. Next, a sorting process is applied on the input data or information matrix, which is intended to prune nonfeasible solutions early in the constructive algorithm. Numerical examples show that the optimization and sorting processes both improve computational efficiency of the original algorithm. Their limits are also shown on certain complex instances.

An artificial bee colony algorithm for uncertain portfolio selection.

Science.gov (United States)

Chen, Wei

2014-01-01

Portfolio selection is an important issue for researchers and practitioners. In this paper, under the assumption that security returns are given by experts' evaluations rather than historical data, we discuss the portfolio adjusting problem which takes transaction costs and diversification degree of portfolio into consideration. Uncertain variables are employed to describe the security returns. In the proposed mean-variance-entropy model, the uncertain mean value of the return is used to measure investment return, the uncertain variance of the return is used to measure investment risk, and the entropy is used to measure diversification degree of portfolio. In order to solve the proposed model, a modified artificial bee colony (ABC) algorithm is designed. Finally, a numerical example is given to illustrate the modelling idea and the effectiveness of the proposed algorithm.

Use of Portfolios by Medical Students: Significance of Critical Thinking

Directory of Open Access Journals (Sweden)

Samy A. Azer

2008-07-01

Full Text Available Portfolios have been used in the medical curriculum to evaluate difficult-to-assess areas such as students' attitudes, professionalism and teamwork. However, their use early in a problem-based learning (PBL course to foster deep learning and enhance students' self-directed learning has not been adequately studied. The aims of this paper are to: (1 understand the uses of portfolios and the rationale for using reflection in the early years of a PBL curriculum; (2 discuss how to introduce portfolios and encourage students' critical thinking skills, not just reflection; and (3 provide students with tips that could enhance their skills in constructing good portfolios.

A dynamic decision model for portfolio investment and assets management

Institute of Scientific and Technical Information of China (English)

QIAN Edward Y.; FENG Ying; HIGGISION James

2005-01-01

This paper addresses a dynamic portfolio investment problem. It discusses how we can dynamically choose candidate assets, achieve the possible maximum revenue and reduce the risk to the minimum level. The paper generalizes Markowitz's portfolio selection theory and Sharpe's rule for investment decision. An analytical solution is presented to show how an institutional or individual investor can combine Markowitz's portfolio selection theory, generalized Sharpe's rule and Value-at-Risk(VaR) to find candidate assets and optimal level of position sizes for investment (dis-investment). The result shows that the generalized Markowitz's portfolio selection theory and generalized Sharpe's rule improve decision making for investment.

Managing the New Product Portfolio

DEFF Research Database (Denmark)

Larsson, Flemming

2008-01-01

Product development companies are increasingly confronted with an unforgiving global marketplace, which urges the top management to pursue every product development opportunity that appears on the road. This situation incurs an important question: Which product development opportunities should a ....... The contributions encourage an improved understanding of the portfolio management concept and support industry professionals in their efforts to compose and continuously maintain a commercially strong product development portfolio.......Product development companies are increasingly confronted with an unforgiving global marketplace, which urges the top management to pursue every product development opportunity that appears on the road. This situation incurs an important question: Which product development opportunities should...

Application of Project Portfolio Management

Science.gov (United States)

Pankowska, Malgorzata

The main goal of the chapter is the presentation of the application project portfolio management approach to support development of e-Municipality and public administration information systems. The models of how people publish and utilize information on the web have been transformed continually. Instead of simply viewing on static web pages, users publish their own content through blogs and photo- and video-sharing slides. Analysed in this chapter, ICT (Information Communication Technology) projects for municipalities cover the mixture of the static web pages, e-Government information systems, and Wikis. So, for the management of the ICT projects' mixtures the portfolio project management approach is proposed.

Statistically Efficient Construction of α-Risk-Minimizing Portfolio

Directory of Open Access Journals (Sweden)

Hiroyuki Taniai

2012-01-01

Full Text Available We propose a semiparametrically efficient estimator for α-risk-minimizing portfolio weights. Based on the work of Bassett et al. (2004, an α-risk-minimizing portfolio optimization is formulated as a linear quantile regression problem. The quantile regression method uses a pseudolikelihood based on an asymmetric Laplace reference density, and asymptotic properties such as consistency and asymptotic normality are obtained. We apply the results of Hallin et al. (2008 to the problem of constructing α-risk-minimizing portfolios using residual signs and ranks and a general reference density. Monte Carlo simulations assess the performance of the proposed method. Empirical applications are also investigated.

Mean-Gini Portfolio Analysis: A Pedagogic Illustration

Directory of Open Access Journals (Sweden)

C. Sherman Cheung

2007-05-01

Full Text Available It is well known in the finance literature that mean-variance analysis is inappropriate when asset returns are not normally distributed or investors’ preferences of returns are not characterized by quadratic functions. The normality assumption has been widely rejected in cases of emerging market equities and hedge funds. The mean-Gini framework is an attractive alternative as it is consistent with stochastic dominance rules regardless of the probability distributions of asset returns. Applying mean-Gini to a portfolio setting involving multiple assets, however, has always been challenging to business students whose training in optimization is limited. This paper introduces a simple spreadsheet-based approach to mean-Gini portfolio optimization, thus allowing the mean-Gini concepts to be covered more effectively in finance courses such as portfolio theory and investment analysis.

Portfolio optimization using fuzzy linear programming

Science.gov (United States)

Pandit, Purnima K.

2013-09-01

Portfolio Optimization (PO) is a problem in Finance, in which investor tries to maximize return and minimize risk by carefully choosing different assets. Expected return and risk are the most important parameters with regard to optimal portfolios. In the simple form PO can be modeled as quadratic programming problem which can be put into equivalent linear form. PO problems with the fuzzy parameters can be solved as multi-objective fuzzy linear programming problem. In this paper we give the solution to such problems with an illustrative example.

Foreign portfolio capital flows and stock returns: a study of Brazilian listed firms

Directory of Open Access Journals (Sweden)

Tiago Rodrigues Loncan

2015-12-01

Full Text Available Abstract This study analyzed the effect of foreign portfolio capital flows on stock returns of Brazilian listed firms through a 6-factors APT model, in which an additional risk factor for foreign portfolio capital flows was included. First, an aggregate analysis was conducted. The partial effect of foreign portfolio capital flows on the IBOVESPA index’s returns was statistically significant and positive. Next, a disaggregate analysis was also implemented, in which portfolios of stocks were sorted by sector of economic activity, level of risk and level of corporate governance. Foreign portfolio capitals caused increases in returns especially for sectors related to commodities, industry and cyclical consumption. For the portfolios sorted by risk (in which the stocks’ betas were used as a risk parameter for sorting, foreign capitals increased the returns of mid-high and high beta portfolios, but decreased the returns of low and low-mid beta portfolios. For corporate governance portfolios, the firms listed on the Novo Mercado segment (according to BMF&Bovespa criteria experienced a statistically significant revaluation effect. Overall, the results of the study provide support to the revaluation effect hypothesis.

A Comparative Analysis of Ability of Mimicking Portfolios in Representing the Background Factors

OpenAIRE

Asgharian, Hossein

2004-01-01

Our aim is to give a comparative analysis of ability of different factor mimicking portfolios in representing the background factors. Our analysis contains a cross-sectional regression approach, a time-series regression approach and a portfolio approach for constructing factor mimicking portfolios. The focus of the analysis is the power of mimicking portfolios in the asset pricing models. We conclude that the time series regression approach, with the book-to-market sorted portfolios as the ba...

Biology and air–sea gas exchange controls on the distribution of carbon isotope ratios (δ13C in the ocean

Directory of Open Access Journals (Sweden)

A. Schmittner

2013-09-01

Full Text Available Analysis of observations and sensitivity experiments with a new three-dimensional global model of stable carbon isotope cycling elucidate processes that control the distribution of δ13C of dissolved inorganic carbon (DIC in the contemporary and preindustrial ocean. Biological fractionation and the sinking of isotopically light δ13C organic matter from the surface into the interior ocean leads to low δ13CDIC values at depths and in high latitude surface waters and high values in the upper ocean at low latitudes with maxima in the subtropics. Air–sea gas exchange has two effects. First, it acts to reduce the spatial gradients created by biology. Second, the associated temperature-dependent fractionation tends to increase (decrease δ13CDIC values of colder (warmer water, which generates gradients that oppose those arising from biology. Our model results suggest that both effects are similarly important in influencing surface and interior δ13CDIC distributions. However, since air–sea gas exchange is slow in the modern ocean, the biological effect dominates spatial δ13CDIC gradients both in the interior and at the surface, in contrast to conclusions from some previous studies. Calcium carbonate cycling, pH dependency of fractionation during air–sea gas exchange, and kinetic fractionation have minor effects on δ13CDIC. Accumulation of isotopically light carbon from anthropogenic fossil fuel burning has decreased the spatial variability of surface and deep δ13CDIC since the industrial revolution in our model simulations. Analysis of a new synthesis of δ13CDIC measurements from years 1990 to 2005 is used to quantify preformed and remineralized contributions as well as the effects of biology and air–sea gas exchange. The model reproduces major features of the observed large-scale distribution of δ13CDIC as well as the individual contributions and effects. Residual misfits are documented and analyzed. Simulated surface and subsurface �

Portfolio optimization for index tracking modelling in Malaysia stock market

Science.gov (United States)

Siew, Lam Weng; Jaaman, Saiful Hafizah; Ismail, Hamizun

2016-06-01

Index tracking is an investment strategy in portfolio management which aims to construct an optimal portfolio to generate similar mean return with the stock market index mean return without purchasing all of the stocks that make up the index. The objective of this paper is to construct an optimal portfolio using the optimization model which adopts regression approach in tracking the benchmark stock market index return. In this study, the data consists of weekly price of stocks in Malaysia market index which is FTSE Bursa Malaysia Kuala Lumpur Composite Index from January 2010 until December 2013. The results of this study show that the optimal portfolio is able to track FBMKLCI Index at minimum tracking error of 1.0027% with 0.0290% excess mean return over the mean return of FBMKLCI Index. The significance of this study is to construct the optimal portfolio using optimization model which adopts regression approach in tracking the stock market index without purchasing all index components.

Successful healthcare programs and projects: organization portfolio management essentials.

Science.gov (United States)

Pickens, Scott; Solak, Jamie

2005-01-01

Many healthcare organization projects take more time and resources than planned and fail to deliver desired business outcomes. Healthcare IT is a major component of many projects and often undeservedly receives the blame for failure. Poor results are often not a result of faulty healthcare IT or poor project management or poor project execution alone. Many projects fail because of poor portfolio management--poor planning and management of the portfolio of initiatives designed to meet an organization's strategic goals. Because resources are limited, portfolio management enables organizations to more strategically allocate and manage their resources so care delivery, service delivery, and initiatives that advance organizations toward their strategic goals, including healthcare IT initiatives, can be accomplished at the levels of quality and service desired by an organization. Proper portfolio management is the essential foundation for program and project success and supports overall organization success. Without portfolio management, even programs and projects that execute flawlessly may not meet desired objectives. This article discusses the essential requirements for porfolio management. These include opportunity identification, return on investment (ROI) forecast, project prioritization, capacity planning (inclusive of human, financial, capital, and facilities resources), work scheduling, program and project management and execution, and project performance and value assessment. Portfolio management is essential to successful healthcare project execution. Theories are drawn from the Organizational Project Management Maturity Model (OPM3) work of the Project Management Institute and other leading strategy, planning, and organization change management research institutes.

Semantic modeling of portfolio assessment in e-learning environment

Directory of Open Access Journals (Sweden)

Lucila Romero

2017-01-01

Full Text Available In learning environment, portfolio is used as a tool to keep track of learner’s progress. Particularly, when it comes to e-learning, continuous assessment allows greater customization and efficiency in learning process and prevents students lost interest in their study. Also, each student has his own characteristics and learning skills that must be taken into account in order to keep learner`s interest. So, personalized monitoring is the key to guarantee the success of technology-based education. In this context, portfolio assessment emerge as the solution because is an easy way to allow teacher organize and personalize assessment according to students characteristic and need. A portfolio assessment can contain various types of assessment like formative assessment, summative assessment, hetero or self-assessment and use different instruments like multiple choice questions, conceptual maps, and essay among others. So, a portfolio assessment represents a compilation of all assessments must be solved by a student in a course, it documents progress and set targets. In previous work, it has been proposed a conceptual framework that consist of an ontology network named AOnet which is a semantic tool conceptualizing different types of assessments. Continuing that work, this paper presents a proposal to implement portfolios assessment in e-learning environments. The proposal consists of a semantic model that describes key components and relations of this domain to set the bases to develop a tool to generate, manage and perform portfolios assessment.

A method for minimum risk portfolio optimization under hybrid uncertainty

Science.gov (United States)

Egorova, Yu E.; Yazenin, A. V.

2018-03-01

In this paper, we investigate a minimum risk portfolio model under hybrid uncertainty when the profitability of financial assets is described by fuzzy random variables. According to Feng, the variance of a portfolio is defined as a crisp value. To aggregate fuzzy information the weakest (drastic) t-norm is used. We construct an equivalent stochastic problem of the minimum risk portfolio model and specify the stochastic penalty method for solving it.

MODERN THEORETICAL APPROACHES CREDIT PORTFOLIO QUALITY MANAGEMENT OF COMMERCIAL BANK

Directory of Open Access Journals (Sweden)

Victoria Lisnic

2016-12-01

Full Text Available Credit portfolio management means the totality of financial and economic decisions realization aimed at achieving optimal ratio of performance indicators of loan portfolio. If low-quality loans increase, the reduction of productive assets volume and, respectively, profitability from banking lending. In extreme cases a such situation could lead to bank bankruptcy. At present bank loan portfolio quality assessment is an important component of bank management.

Strategic biopharmaceutical portfolio development: an analysis of constraint-induced implications.

Science.gov (United States)

George, Edmund D; Farid, Suzanne S

2008-01-01

Optimizing the structure and development pathway of biopharmaceutical drug portfolios are core concerns to the developer that come with several attached complexities. These include strategic decisions for the choice of drugs, the scheduling of critical activities, and the possible involvement of third parties for development and manufacturing at various stages for each drug. Additional complexities that must be considered include the impact of making such decisions in an uncertain environment. Presented here is the development of a stochastic multi-objective optimization framework designed to address these issues. The framework harnesses the ability of Bayesian networks to characterize the probabilistic structure of superior decisions via machine learning and evolve them to multi-objective optimality. Case studies that entailed three- and five-drug portfolios alongside a range of cash flow constraints were constructed to derive insight from the framework where results demonstrate that a variety of options exist for formulating nondominated strategies in the objective space considered, giving the manufacturer a range of pursuable options. In all cases limitations on cash flow reduce the potential for generating profits for a given probability of success. For the sizes of portfolio considered, results suggest that naïvely applying strategies optimal for a particular size of portfolio to a portfolio of another size is inappropriate. For the five-drug portfolio the most preferred means for development across the set of optimized strategies is to fully integrate development and commercial activities in-house. For the three-drug portfolio, the preferred means of development involves a mixture of in-house, outsourced, and partnered activities. Also, the size of the portfolio appears to have a larger impact on strategy and the quality of objectives than the magnitude of cash flow constraint.

Digital portfolio som metode og pædagogik

DEFF Research Database (Denmark)

Toft, Hanne; Luplau Schnefeld, Mette

2004-01-01

Artiklen præsenterer erfaringer med digital portfolio som didaktik og metode. Fokus er på kobling mellem didaktiske læreprocesser på en grunduddannelse og så understøttelse af disse via brug af en digital portfolio. Portfolioen adskiller en række forskellige dokumentsamlinger i privat og offentlig...

The biological pump: Profiles of plankton production and consumption in the upper ocean

Science.gov (United States)

Longhurst, Alan R.; Glen Harrison, W.

The ‘biological pump’ mediates flux of carbon to the interior of the ocean by interctions between the components of the vertically-structured pelagic ecosystem of the photic zone. Chlorophyll profiles are not a simple indicator of autotrophic biomass or production, because of non-linearities in the physiology of cells and preferential vertical distribution of taxa. Profiles of numbers or biomass of heterotrophs do not correspond with profiles of consumption, because of depth-selection (taxa, seasons) for reasons unconnected with feeding. Depths of highest plant biomass, chlorophyll and growth rate coincide when these depths are shallow, but become progressively separated in profiles where they are deeper - so that highest growth rate lies progressively shallower than the chloropyll maximum. It is still uncertain how plant biomass is distributed in deep profiles. Depths of greatest heterotroph biomass (mesozooplankton) are usually close to depths of fastest plant growth rate, and thus lie shallower than the chlorophyll maximum in profiles where this itself is deep. This correlation is functional, and relates to the role of heterotrophs in excreting metabolic wastes (especially ammonia), which may fuel a significant component of integrated algal production, especially in the oligotrophic ocean. Some, but not all faecal material from mesozooplankton of the photic zone appears in vertical flux below the pycnocine, depending on the size of the source organisms, and the degree of vertical mixing above the pycnocline. Diel, but probably not seasonal, vertical migration is significant in the vertical flux of dissolved nitrogen. Regional generalisations of the vertical relations of the main components of the ‘biological pump’ now appear within reach, and an approach is suggested.

Portfolio Selection with Jumps under Regime Switching

Directory of Open Access Journals (Sweden)

Lin Zhao

2010-01-01

Full Text Available We investigate a continuous-time version of the mean-variance portfolio selection model with jumps under regime switching. The portfolio selection is proposed and analyzed for a market consisting of one bank account and multiple stocks. The random regime switching is assumed to be independent of the underlying Brownian motion and jump processes. A Markov chain modulated diffusion formulation is employed to model the problem.

Equity Portfolio Management Using Option Price Information

DEFF Research Database (Denmark)

Christoffersen, Peter; Pan, Xuhui (Nick)

We survey the recent academic literature that uses option-implied information to construct equity portfolios. Studies show that equity managers can earn a positive alpha by using information in individual equity options, by using stocks' exposure to information in market index options, and by using...... stocks' exposure to crude oil option information. Option-implied information can also help construct better mean-variance portfolios and better estimates of market beta....

Essays on portfolio choice with Bayesian methods

OpenAIRE

Kebabci, Deniz

2007-01-01

How investors should allocate assets to their portfolios in the presence of predictable components in asset returns is a question of great importance in finance. While early studies took the return generating process as given, recent studies have addressed issues such as parameter estimation and model uncertainty. My dissertation develops Bayesian methods for portfolio choice - and industry allocation in particular - under parameter and model uncertainty. The first chapter of my dissertation,...

Project Portfolio Risk Identification and Analysis, Considering Project Risk Interactions and Using Bayesian Networks

Directory of Open Access Journals (Sweden)

Foroogh Ghasemi

2018-05-01

Full Text Available An organization’s strategic objectives are accomplished through portfolios. However, the materialization of portfolio risks may affect a portfolio’s sustainable success and the achievement of those objectives. Moreover, project interdependencies and cause–effect relationships between risks create complexity for portfolio risk analysis. This paper presents a model using Bayesian network (BN methodology for modeling and analyzing portfolio risks. To develop this model, first, portfolio-level risks and risks caused by project interdependencies are identified. Then, based on their cause–effect relationships all portfolio risks are organized in a BN. Conditional probability distributions for this network are specified and the Bayesian networks method is used to estimate the probability of portfolio risk. This model was applied to a portfolio of a construction company located in Iran and proved effective in analyzing portfolio risk probability. Furthermore, the model provided valuable information for selecting a portfolio’s projects and making strategic decisions.

Qualitative study of the impact of an authentic electronic portfolio in undergraduate medical education.

Science.gov (United States)

Belcher, Rosie; Jones, Anna; Smith, Laura-Jane; Vincent, Tim; Naidu, Sindhu Bhaarrati; Montgomery, Julia; Haq, Inam; Gill, Deborah

2014-12-17

Portfolios are increasingly used in undergraduate and postgraduate medical education. Four medical schools have collaborated with an established NHS electronic portfolio provider to develop and implement an authentic professional electronic portfolio for undergraduate students. We hypothesized that using an authentic portfolio would have significant advantages for students, particularly in familiarizing them with the tool many will continue to use for years after graduation. This paper describes the early evaluation of this undergraduate portfolio at two participating medical schools. To gather data, a questionnaire survey with extensive free text comments was used at School 1, and three focus groups were held at School 2. This paper reports thematic analysis of students' opinions expressed in the free text comments and focus groups. Five main themes, common across both schools were identified. These concerned the purpose, use and acceptability of the portfolio, advantages of and barriers to the use of the portfolio, and the impacts on both learning and professional identity. An authentic portfolio mitigated some of the negative aspects of using a portfolio, and had a positive effect on students' perception of themselves as becoming past of the profession. However, significant barriers to portfolio use remained, including a lack of understanding of the purpose of a portfolio and a perceived damaging effect on feedback.

A proposed selection process in Over-The-Top project portfolio management

Directory of Open Access Journals (Sweden)

Jemy Vestius Confido

2018-05-01

Full Text Available Purpose: The purpose of this paper is to propose an Over-The-Top (OTT initiative selection process for communication service providers (CSPs entering an OTT business. Design/methodology/approach: To achieve this objective, a literature review was conducted to comprehend the past and current practices of the project (or initiative selection process as mainly suggested in project portfolio management (PPM. This literature was compared with specific situations and the needs of CSPs when constructing an OTT portfolio. Based on the contrast between the conventional project selection process and specific OTT characteristics, a different selection process is developed and tested using group model-building (GMB, which involved an in-depth interview, a questionnaire and a focus group discussion (FGD. Findings: The paper recommends five distinct steps for CSPs to construct an OTT initiative portfolio: candidate list of OTT initiatives, interdependency diagram, evaluation of all interdependent OTT initiatives, evaluation of all non-interdependent OTT initiatives and optimal portfolio of OTT initiatives. Research limitations/implications: The research is empirical, and various OTT services are implemented; the conclusion is derived only from one CSP, which operates as a group. Generalization of this approach will require further empirical tests on different CSPs, OTT players or any firms performing portfolio selection with a degree of interdependency among the projects. Practical implications: Having considered interdependency, the proposed OTT initiative selection steps can be further implemented by portfolio managers for more effective OTT initiative portfolio construction. Originality/value: While the previous literature and common practices suggest ensuring the benefits (mainly financial of individual projects, this research accords higher priority to the success of the overall OTT initiative portfolio and recommends that an evaluation of the overall

Portfolio Sensitivity Model for Analyzing Credit Risk Caused by Structural and Macroeconomic Changes

Directory of Open Access Journals (Sweden)

Goran Klepac

2008-12-01

Full Text Available This paper proposes a new model for portfolio sensitivity analysis. The model is suitable for decision support in financial institutions, specifically for portfolio planning and portfolio management. The basic advantage of the model is the ability to create simulations for credit risk predictions in cases when we virtually change portfolio structure and/or macroeconomic factors. The model takes a holistic approach to portfolio management consolidating all organizational segments in the process such as marketing, retail and risk.

Designing a portfolio management programme to optimize cash-flow

International Nuclear Information System (INIS)

Fassom, D.

1996-01-01

The design and implementation of any portfolio management programme must, by definition, be tailored to the drivers and particular objectives of the company owning the assets. This paper will concentrate on one of the most important driving forces, namely managing cash-flow. Five key steps are required to achieve an effective portfolio management programme: 1. establish targets/goals; 2. describe and value the assets in your company's portfolio; 3. identify and catalogue potential 'customers'; 4. construct appropriate deal structures and other strategies to achieve your targets; 5. work hard and do deals. (author)

An Empirical Exploration of the Antecedents and Outcomes of NPD Portfolio Success

NARCIS (Netherlands)

Kester, L.; Hultink, H.J.; Griffin, A.

2013-01-01

The manuscript first combines theory and previous empirical findings to build a model of new product development portfolio success. Because relationships between product development portfolio decision-making effectiveness, portfolio success and firm-level success have not previously been

The feasibility and acceptability of using a portfolio to assess professional competence.

Science.gov (United States)

Miller, Patricia A; Tuekam, Rosine

2011-01-01

Little is known about physical therapists' views on the use of portfolios to evaluate professional competence. The purpose of this study was to gather the opinions of physical therapists on the feasibility and acceptability of a portfolio prepared to demonstrate evidence of clinical specialization through reported activities and accomplishments related to professional development, leadership, and research. Twenty-nine Canadian physical therapists practising in the neurosciences area were given 8 weeks to prepare a professional portfolio. Participants submitted the portfolio along with a survey addressing the preparation of the portfolio and its role as an assessment tool. Qualitative content analysis was used to interpret the participants' comments. Participants reported that maintaining organized records facilitated the preparation of their portfolio. They experienced pride when reviewing their completed portfolios, which summarized their professional activities and highlighted their achievements. Concerns were noted about the veracity of self-reported records and the ability of the documentation to provide a comprehensive view of the full scope of the professional competencies required for clinical specialization (e.g., clinical skills). The study's findings support the feasibility and acceptability of a portfolio review to assess professional competence and clinical specialization in physical therapy and have implications for both physical therapists and professional agencies.

The Use of Academic Portfolio in the Learning and Assessment of Physics Students

Directory of Open Access Journals (Sweden)

Meng Kay Ling

2016-05-01

Full Text Available The purpose of this research paper is to examine the use of portfolios in the teaching and learning of physics at a Singapore private college. The paper starts with a short introduction of the types of students and the purpose of using academic portfolios in their learning and assessment. Some ideas of how portfolios can be used in the local context will also be discussed. It is necessary for teachers to know how to incorporate portfolio assessment in their daily lesson plans. At the same time, students who are studying physics at the college should also know how to use portfolios to their academic advantage. The paper also highlights three of the relevant work artifacts that can be included into the physics portfolios. The three work samples are concept-maps, internet research reports and newspaper articles reports. Concept-maps are useful tools to help students establish the connections between concepts. Internet research reports serve as important means for students to know more about how some scientific devices or technology use physics in the operations. Newspaper articles reports allow students to understand the real impact of physics on the lives of people. Subsequent sections of the paper discuss about the organizational flow of the portfolio, the timeline, the selection process, the portfolio checklist and assessment rubrics, the positive influences of using portfolios, the issues to consider and also the potential problems that physics teachers may face in implementing portfolios. These sections present the important framework which teachers can use as references for their portfolio initiatives in schools.

New perspectives in ocean acidification research: editor's introduction to the special feature on ocean acidification.

Science.gov (United States)

Munday, Philip L

2017-09-01

Ocean acidification, caused by the uptake of additional carbon dioxide (CO 2 ) from the atmosphere, will have far-reaching impacts on marine ecosystems (Gattuso & Hansson 2011 Ocean acidification Oxford University Press). The predicted changes in ocean chemistry will affect whole biological communities and will occur within the context of global warming and other anthropogenic stressors; yet much of the biological research conducted to date has tested the short-term responses of single species to ocean acidification conditions alone. While an important starting point, these studies may have limited predictive power because they do not account for possible interactive effects of multiple climate change drivers or for ecological interactions with other species. Furthermore, few studies have considered variation in responses among populations or the evolutionary potential within populations. Therefore, our knowledge about the potential for marine organisms to adapt to ocean acidification is extremely limited. In 2015, two of the pioneers in the field, Ulf Riebesell and Jean-Pierre Gattuso, noted that to move forward as a field of study, future research needed to address critical knowledge gaps in three major areas: (i) multiple environmental drivers, (ii) ecological interactions and (iii) acclimation and adaptation (Riebesell and Gattuso 2015 Nat. Clim. Change 5 , 12-14 (doi:10.1038/nclimate2456)). In May 2016, more than 350 researchers, students and stakeholders met at the 4th International Symposium on the Ocean in a High-CO 2 World in Hobart, Tasmania, to discuss the latest advances in understanding ocean acidification and its biological consequences. Many of the papers presented at the symposium reflected this shift in focus from short-term, single species and single stressor experiments towards multi-stressor and multispecies experiments that address knowledge gaps about the ecological impacts of ocean acidification on marine communities. The nine papers in this

Using portfolios to introduce the clinical nurse leader to the job market.

Science.gov (United States)

Norris, Tommie L; Webb, Sherry S; McKeon, Leslie M; Jacob, Susan R; Herrin-Griffith, Donna

2012-01-01

Development of a portfolio is an effective strategy used by clinical nurse leaders (CNLs) to inform prospective employers of their specialized skills in quality improvement, patient safety, error prevention, and teamwork. The portfolio provides evidence of competence relative to the role of clinician, outcomes manager, client advocate, educator, information manager, systems analyst/risk anticipator, team manager, healthcare professional, and lifelong learner. This article describes the CNL portfolio developed by experts from the University of Tennessee Health Science Center and Methodist LeBonheur Healthcare. Examples of portfolio documents generated throughout the master's entry CNL curriculum are provided, along with student experiences using the portfolio in the employment interview process.

Developing a Template for Electronic Portfolios in Career and Technical Education

Science.gov (United States)

Fowler, Matthew

2012-01-01

The purposes of this multiple case study were to determine if manufacturing and services sector employers found value in the use of an ePortfolio in the hiring process, and to develop a suggested template for an ePortfolio format to be used within career and technical education. Electronic portfolios "allow students to showcase their…

E-Portfolios in Teacher Development: The Better Option?

Science.gov (United States)

Xerri, Daniel; Campbell, Caroline

2016-01-01

Following the introduction of print portfolios for teacher development in the ELT sector in Malta, this article discusses the findings of a small-scale study that highlighted teachers' views in relation to the possible future implementation of e-portfolios. It shows that while aware of the benefits of this tool, teachers have concerns about their…

A Holocaust Exhibit ePortfolio: Actively Engaging Students

Science.gov (United States)

Jordine, Melissa

2015-01-01

California State University, Fresno is currently considering implementing an ePortfolio requirement for all undergraduate students. The ePortfolio requirement would be introduced primarily to engage students in a HIP (high impact practice) but would also be used for assessment purposes. As a faculty member and a member of the CSU Fresno ePortfolio…

Portfolio optimization of the construction sector companies in ...

African Journals Online (AJOL)

The objective of this paper is to construct the optimal portfolio that will minimize the portfolio risk and can achieve the investors target rate of return by using the mean-semi absolute deviation model. The data of this study comprises 20 construction sector companies that listed in Malaysia stock market from July 2011 until ...

Vacation portfolio decisions: analysis using a Bayesian belief network

NARCIS (Netherlands)

Grigolon, A.B.; Kemperman, A.D.A.M.; Timmermans, H.J.P.

2011-01-01

The aim of this study is to analyse the extent to which vacation portfolio decisions are influenced by socio-demographic characteristics. A vacation portfolio involves interdependent decisions related to the facets that make the vacation trip, including transport mode, accommodation, destination,

Portfolio selection theory and wildlife management | Hearne | ORiON

African Journals Online (AJOL)

Portfolio selection theory and wildlife management. ... Abstract. With a strong commercial incentive driving the increase in game ranching in Southern Africa the need has come for more advanced management tools. ... Keywords: Portfolio selection, multi-objective optimisation, game ranching, wildlife management.

Portfolio Implementation Risk Management Using Evolutionary Multiobjective Optimization

Directory of Open Access Journals (Sweden)

David Quintana

2017-10-01

Full Text Available Portfolio management based on mean-variance portfolio optimization is subject to different sources of uncertainty. In addition to those related to the quality of parameter estimates used in the optimization process, investors face a portfolio implementation risk. The potential temporary discrepancy between target and present portfolios, caused by trading strategies, may expose investors to undesired risks. This study proposes an evolutionary multiobjective optimization algorithm aiming at regions with solutions more tolerant to these deviations and, therefore, more reliable. The proposed approach incorporates a user’s preference and seeks a fine-grained approximation of the most relevant efficient region. The computational experiments performed in this study are based on a cardinality-constrained problem with investment limits for eight broad-category indexes and 15 years of data. The obtained results show the ability of the proposed approach to address the robustness issue and to support decision making by providing a preferred part of the efficient set. The results reveal that the obtained solutions also exhibit a higher tolerance to prediction errors in asset returns and variance–covariance matrix.

Belief Propagation Algorithm for Portfolio Optimization Problems.

Science.gov (United States)

Shinzato, Takashi; Yasuda, Muneki

2015-01-01

The typical behavior of optimal solutions to portfolio optimization problems with absolute deviation and expected shortfall models using replica analysis was pioneeringly estimated by S. Ciliberti et al. [Eur. Phys. B. 57, 175 (2007)]; however, they have not yet developed an approximate derivation method for finding the optimal portfolio with respect to a given return set. In this study, an approximation algorithm based on belief propagation for the portfolio optimization problem is presented using the Bethe free energy formalism, and the consistency of the numerical experimental results of the proposed algorithm with those of replica analysis is confirmed. Furthermore, the conjecture of H. Konno and H. Yamazaki, that the optimal solutions with the absolute deviation model and with the mean-variance model have the same typical behavior, is verified using replica analysis and the belief propagation algorithm.

Belief Propagation Algorithm for Portfolio Optimization Problems.

Directory of Open Access Journals (Sweden)

Takashi Shinzato

Full Text Available The typical behavior of optimal solutions to portfolio optimization problems with absolute deviation and expected shortfall models using replica analysis was pioneeringly estimated by S. Ciliberti et al. [Eur. Phys. B. 57, 175 (2007]; however, they have not yet developed an approximate derivation method for finding the optimal portfolio with respect to a given return set. In this study, an approximation algorithm based on belief propagation for the portfolio optimization problem is presented using the Bethe free energy formalism, and the consistency of the numerical experimental results of the proposed algorithm with those of replica analysis is confirmed. Furthermore, the conjecture of H. Konno and H. Yamazaki, that the optimal solutions with the absolute deviation model and with the mean-variance model have the same typical behavior, is verified using replica analysis and the belief propagation algorithm.

Forecast Correlation Coefficient Matrix of Stock Returns in Portfolio Analysis

OpenAIRE

Zhao, Feng

2013-01-01

In Modern Portfolio Theory, the correlation coefficients decide the risk of a set of stocks in the portfolio. So, to understand the correlation coefficients between returns of stocks, is a challenge but is very important for the portfolio management. Usually, the stocks with small correlation coefficients or even negative correlation coefficients are preferred. One can calculate the correlation coefficients of stock returns based on the historical stock data. However, in order to control the ...

Analysis of the rebalancing frequency in log-optimal portfolio selection

OpenAIRE

Kuhn, Daniel; Luenberger, David G.

2010-01-01

In a dynamic investment situation, the right timing of portfolio revisions and adjustments is essential to sustain long-term growth. A high rebalancing frequency reduces the portfolio performance in the presence of transaction costs, whereas a low rebalancing frequency entails a static investment strategy that hardly reacts to changing market conditions. This article studies a family of portfolio problems in a Black-Scholes type economy which depend parametrically on the rebalancing frequency...

Teacher Electronic Portfolio and its Relation to EFL Student Teacher Performance and Attitude

Directory of Open Access Journals (Sweden)

Areej T Alshawi

2017-01-01

Full Text Available E-portfolio is a promising approach to develop teachers into reflective practitioners who show that they can adapt to new technologies, new criteria, and new environments. The current research explored the quality of EFL student teachers’ e-portfolios and their attitudes towards using them. The research was conducted on 30 EFL female student teachers at Princess Noura bint Abdulrahman University, Saudi Arabia. The participants were engaging in practical training at schools and reflecting their skills and experiences in their e-portfolios. This research posed further questions about the relationships between the quality of EFL student teachers’ e-portfolios, their attitudes towards using them and their teaching performance. In order to explore the possible answers, the participants’ teaching performance were observed, their e-portfolios were evaluated by a rubric, and a 24-item questionnaire was administered to them. The results proved high proficiency level of the EFL student teachers’ e-portfolios and positive attitudes towards using e-portfolios among EFL student teachers. Furthermore, the results denoted a statistically significant positive relationship between the quality of EFL student teachers’ e-portfolio and their teaching performance. The results of this study may encourage policy makers to integrate the idea of e-portfolio and reflection as an effective component in teacher education and development.

Exploring the role of assessment criteria during teachers' collaborative judgement processes of students' portfolios

NARCIS (Netherlands)

Schaaf, van der M.F.; Baartman, L.K.J.; Prins, F.J.

2012-01-01

Student portfolios are increasingly used for assessing student competences in higher education, but results about the construct validity of portfolio assessment are mixed. A prerequisite for construct validity is that the portfolio assessment is based on relevant portfolio content. Assessment

Towards a TENCompetence ePortfolio

Directory of Open Access Journals (Sweden)

Adriana J. Berlanga

2008-07-01

Full Text Available This article argues that the TENCompetence ePortfolio definition should integrate rhetorical, pedagogical, social, and technical perspectives. The rhetorical perspective is needed to show the learner’s competences, achievements and history; the pedagogical perspective aims at supporting learner’s self-reflection, through the definition of competences mastered, review and creation of (new competence development plans, and assessment of competences; the social perspective aims at fostering interaction and social help support; and the technical perspective aims at supporting the other three perspectives. Guiding principles for the design of the TENCompetence ePortfolio are provided, and the aforementioned perspectives detailed.

Online Learning of Commission Avoidant Portfolio Ensembles

OpenAIRE

Uziel, Guy; El-Yaniv, Ran

2016-01-01

We present a novel online ensemble learning strategy for portfolio selection. The new strategy controls and exploits any set of commission-oblivious portfolio selection algorithms. The strategy handles transaction costs using a novel commission avoidance mechanism. We prove a logarithmic regret bound for our strategy with respect to optimal mixtures of the base algorithms. Numerical examples validate the viability of our method and show significant improvement over the state-of-the-art.

The regional electricity generation mix in Scotland: A portfolio selection approach incorporating marine technologies

International Nuclear Information System (INIS)

Allan, Grant; Eromenko, Igor; McGregor, Peter; Swales, Kim

2011-01-01

Standalone levelised cost assessments of electricity supply options miss an important contribution that renewable and non-fossil fuel technologies can make to the electricity portfolio: that of reducing the variability of electricity costs, and their potentially damaging impact upon economic activity. Portfolio theory applications to the electricity generation mix have shown that renewable technologies, their costs being largely uncorrelated with non-renewable technologies, can offer such benefits. We look at the existing Scottish generation mix and examine drivers of changes out to 2020. We assess recent scenarios for the Scottish generation mix in 2020 against mean-variance efficient portfolios of electricity-generating technologies. Each of the scenarios studied implies a portfolio cost of electricity that is between 22% and 38% higher than the portfolio cost of electricity in 2007. These scenarios prove to be mean-variance 'inefficient' in the sense that, for example, lower variance portfolios can be obtained without increasing portfolio costs, typically by expanding the share of renewables. As part of extensive sensitivity analysis, we find that Wave and Tidal technologies can contribute to lower risk electricity portfolios, while not increasing portfolio cost. - Research Highlights: → Portfolio analysis of scenarios for Scotland's electricity generating mix in 2020. → Reveals potential inefficiencies of selecting mixes based on levelised cost alone. → Portfolio risk-reducing contribution of Wave and Tidal technologies assessed.

The regional electricity generation mix in Scotland: A portfolio selection approach incorporating marine technologies

Energy Technology Data Exchange (ETDEWEB)

Allan, Grant, E-mail: grant.j.allan@strath.ac.u [Fraser of Allander Institute, Department of Economics, University of Strathclyde, Sir William Duncan Building, 130 Rottenrow, Glasgow G4 0GE (United Kingdom); Eromenko, Igor; McGregor, Peter [Fraser of Allander Institute, Department of Economics, University of Strathclyde, Sir William Duncan Building, 130 Rottenrow, Glasgow G4 0GE (United Kingdom); Swales, Kim [Department of Economics, University of Strathclyde, Sir William Duncan Building, 130 Rottenrow, Glasgow G4 0GE (United Kingdom)

2011-01-15

Standalone levelised cost assessments of electricity supply options miss an important contribution that renewable and non-fossil fuel technologies can make to the electricity portfolio: that of reducing the variability of electricity costs, and their potentially damaging impact upon economic activity. Portfolio theory applications to the electricity generation mix have shown that renewable technologies, their costs being largely uncorrelated with non-renewable technologies, can offer such benefits. We look at the existing Scottish generation mix and examine drivers of changes out to 2020. We assess recent scenarios for the Scottish generation mix in 2020 against mean-variance efficient portfolios of electricity-generating technologies. Each of the scenarios studied implies a portfolio cost of electricity that is between 22% and 38% higher than the portfolio cost of electricity in 2007. These scenarios prove to be mean-variance 'inefficient' in the sense that, for example, lower variance portfolios can be obtained without increasing portfolio costs, typically by expanding the share of renewables. As part of extensive sensitivity analysis, we find that Wave and Tidal technologies can contribute to lower risk electricity portfolios, while not increasing portfolio cost. - Research Highlights: {yields} Portfolio analysis of scenarios for Scotland's electricity generating mix in 2020. {yields} Reveals potential inefficiencies of selecting mixes based on levelised cost alone. {yields} Portfolio risk-reducing contribution of Wave and Tidal technologies assessed.

Portfolio Management with Stochastic Interest Rates and Inflation Ambiguity

DEFF Research Database (Denmark)

Munk, Claus; Rubtsov, Alexey Vladimirovich

2014-01-01

prices. The investor is ambiguous about the inflation model and prefers a portfolio strategy which is robust to model misspecification. Ambiguity about the inflation dynamics is shown to affect the optimal portfolio fundamentally different than ambiguity about the price dynamics of traded assets...

Discourses and Theoretical Assumptions in IT Project Portfolio Management

DEFF Research Database (Denmark)

Hansen, Lars Kristian; Kræmmergaard, Pernille

2014-01-01

DISCOURSES AND THEORETICAL ASSUMPTIONS IN IT PROJECT PORTFOLIO MANAGEMENT: A REVIEW OF THE LITERATURE These years increasing interest is put on IT project portfolio management (IT PPM). Considering IT PPM an interdisciplinary practice, we conduct a concept-based literature review of relevant...

A Real Options Perspective On R&D Portfolio Diversification

NARCIS (Netherlands)

S. van Bekkum (Sjoerd); H.P.G. Pennings (Enrico); J.T.J. Smit (Han)

2009-01-01

textabstractThis paper shows that the conditionality of investment decisions in R&D has a critical impact on portfolio risk, and implies that traditional diversification strategies should be reevaluated when a portfolio is constructed. Real option theory argues that research projects have

A Real Options Perspective on R&D Portfolio Diversification

NARCIS (Netherlands)

S. van Bekkum (Sjoerd); H.P.G. Pennings (Enrico); J.T.J. Smit (Han)

2008-01-01

textabstractThis paper shows that the presence of conditional staging in R&D (Research & Development) has a critical impact on portfolio risk, and changes diversification arguments when a portfolio is constructed. When R&D projects exhibit option-like characteristics, correlation between projects

Portfolio allocation under the vendor managed inventory: A Markov ...

African Journals Online (AJOL)

Portfolio allocation under the vendor managed inventory: A Markov decision process. ... Journal of Applied Sciences and Environmental Management ... This study provides a review of Markov decision processes and investigates its suitability for solutions to portfolio allocation problems under vendor managed inventory in ...

Portfolios with fuzzy returns: Selection strategies based on semi-infinite programming

Science.gov (United States)

Vercher, Enriqueta

2008-08-01

This paper provides new models for portfolio selection in which the returns on securities are considered fuzzy numbers rather than random variables. The investor's problem is to find the portfolio that minimizes the risk of achieving a return that is not less than the return of a riskless asset. The corresponding optimal portfolio is derived using semi-infinite programming in a soft framework. The return on each asset and their membership functions are described using historical data. The investment risk is approximated by mean intervals which evaluate the downside risk for a given fuzzy portfolio. This approach is illustrated with a numerical example.

Portfolio management for investment projects in the construction industry

Directory of Open Access Journals (Sweden)

Kozlov Alexander

2017-01-01

Full Text Available The Russian business community has realized the need for project/targeted programme management procedures; therefore, the demand for customized project-oriented management methods goes up. In the meantime, this demand is not supplied in full, and the supply is far from being efficient. Project management methodologies need further improvement, including development of portfolio management processes applicable to investment projects developed and implemented in the construction industry. The article considers General approaches to the formalization of the management of portfolios of investment–construction projects. For the main groups of processes portfolio management (“Formation and alignment”, “Monitoring and control” and “Support and development” deals with their constituent sub-processes. The proposed decomposition can be used for both portfolio construction and investment projects and also has an invariant character, which allows extending the proposed approaches to other system target–oriented and project–oriented management.

Fuzzy portfolio optimization advances in hybrid multi-criteria methodologies

CERN Document Server

Gupta, Pankaj; Inuiguchi, Masahiro; Chandra, Suresh

2014-01-01

This monograph presents a comprehensive study of portfolio optimization, an important area of quantitative finance. Considering that the information available in financial markets is incomplete and that the markets are affected by vagueness and ambiguity, the monograph deals with fuzzy portfolio optimization models. At first, the book makes the reader familiar with basic concepts, including the classical mean–variance portfolio analysis. Then, it introduces advanced optimization techniques and applies them for the development of various multi-criteria portfolio optimization models in an uncertain environment. The models are developed considering both the financial and non-financial criteria of investment decision making, and the inputs from the investment experts. The utility of these models in practice is then demonstrated using numerical illustrations based on real-world data, which were collected from one of the premier stock exchanges in India. The book addresses both academics and professionals pursuin...

Portfolio assessment during medical internships: How to obtain a reliable and feasible assessment procedure?

Science.gov (United States)

Michels, Nele R M; Driessen, Erik W; Muijtjens, Arno M M; Van Gaal, Luc F; Bossaert, Leo L; De Winter, Benedicte Y

2009-12-01

A portfolio is used to mentor and assess students' clinical performance at the workplace. However, students and raters often perceive the portfolio as a time-consuming instrument. In this study, we investigated whether assessment during medical internship by a portfolio can combine reliability and feasibility. The domain-oriented reliability of 61 double-rated portfolios was measured, using a generalisability analysis with portfolio tasks and raters as sources of variation in measuring the performance of a student. We obtained reliability (Phi coefficient) of 0.87 with this internship portfolio containing 15 double-rated tasks. The generalisability analysis showed that an acceptable level of reliability (Phi = 0.80) was maintained when the amount of portfolio tasks was decreased to 13 or 9 using one and two raters, respectively. Our study shows that a portfolio can be a reliable method for the assessment of workplace learning. The possibility of reducing the amount of tasks or raters while maintaining a sufficient level of reliability suggests an increase in feasibility of portfolio use for both students and raters.

An isopycnic ocean carbon cycle model

Directory of Open Access Journals (Sweden)

K. M. Assmann

2010-02-01

Full Text Available The carbon cycle is a major forcing component in the global climate system. Modelling studies, aiming to explain recent and past climatic changes and to project future ones, increasingly include the interaction between the physical and biogeochemical systems. Their ocean components are generally z-coordinate models that are conceptually easy to use but that employ a vertical coordinate that is alien to the real ocean structure. Here, we present first results from a newly-developed isopycnic carbon cycle model and demonstrate the viability of using an isopycnic physical component for this purpose. As expected, the model represents well the interior ocean transport of biogeochemical tracers and produces realistic tracer distributions. Difficulties in employing a purely isopycnic coordinate lie mainly in the treatment of the surface boundary layer which is often represented by a bulk mixed layer. The most significant adjustments of the ocean biogeochemistry model HAMOCC, for use with an isopycnic coordinate, were in the representation of upper ocean biological production. We present a series of sensitivity studies exploring the effect of changes in biogeochemical and physical processes on export production and nutrient distribution. Apart from giving us pointers for further model development, they highlight the importance of preformed nutrient distributions in the Southern Ocean for global nutrient distributions. The sensitivity studies show that iron limitation for biological particle production, the treatment of light penetration for biological production, and the role of diapycnal mixing result in significant changes of nutrient distributions and liniting factors of biological production.

A Dynamic Spreadsheet Model for Determining the Portfolio Frontier for BSE30 Stocks

Directory of Open Access Journals (Sweden)

Dr. Anupam Mitra

2014-01-01

Full Text Available Introductory investments courses revolve around Harry Markowitz’s modern portfolio theory and William Sharpe’s Index for the performance measurement of those portfolios. This paper presents a simplified perspective of Markowitz’s contributions to Modern Portfolio Theory. It is to see the effect of duration of historical data on the risk and return of the portfolio and to see the applicability of risk-reward logic. The empirical results also show that short selling may increase the risk of the portfolio when the investor is instability preferred.

PORTFOLIO ANALYSIS BASED ON THE EXAMPLE OF ZAGREB STOCK EXCHANGE

Directory of Open Access Journals (Sweden)

Sinisa Bogdan

2010-06-01

Full Text Available In this paper we analyze the portfolio that was selected from the Zagreb Stock Exchange and also try to assess its risks and its future offerings that are relevant in making the decisions about investments. Through the work we will explain the importance of diversification and how the very diversification reduces risk. We will also analyze the systemic risk of individual stocks within the portfolio and the systemic risk of the given portfolio and explain its importance. Through regression analysis we will analyze the securities with the highest and lowest systemic risk and will clarify the results. At the end we will explain the correlation in the selected portfolio and point out the importance of the correlation and diversification itself.

Long term contracts in portfolios of core LDC gas supply

International Nuclear Information System (INIS)

John, F.E.

1992-01-01

This paper recommends that local distribution companies (LDCs) should use a portfolio approach for their gas supply strategy. The author recommends that LDCs not rely on spot supplies to meet the peak needs of the core residential and commercial markets. He recommends that a secure supply through long-term contracts are better sources than spot or even intermediate term suppliers. The paper provides a brief outline format of the advantages to the use of a portfolio approach which include the rapid restructuring of the market, general changes in the market, and general market performance. By maintaining a portfolio, a list of available natural gas suppliers is always available. This portfolio also acts to compare pricing between short, medium, and long-term pricing for the LDCs

Portfolio selection theory and wildlife management

Directory of Open Access Journals (Sweden)

JW Hearne

2008-12-01

Full Text Available With a strong commercial incentive driving the increase in game ranching in Southern Africa the need has come for more advanced management tools. In this paper the potential of Portfolio Selection Theory to determine the optimal mix of species on game ranches is explored. Land, or the food it produces, is a resource available to invest. We consider species as investment choices. Each species has its own return and risk profile. The question arises as to what proportion of the resource available should be invested in each species. We show that if the objective is to minimise risk for a given return, then the problem is analogous to the Portfolio Selection Problem. The method is then implemented for a typical game ranch. We show that besides risk and return objectives, it is necessary to include an additional objective so as to ensure sufficient species to maintain the character of a game ranch. Some other points of difference from the classical Portfolio Selection problem are also highlighted and discussed.

Optimization Stock Portfolio With Mean-Variance and Linear Programming: Case In Indonesia Stock Market

Directory of Open Access Journals (Sweden)

Yen Sun

2010-05-01

Full Text Available It is observed that the number of Indonesia’s domestic investor who involved in the stock exchange is very less compare to its total number of population (only about 0.1%. As a result, Indonesia Stock Exchange (IDX is highly affected by foreign investor that can threat the economy. Domestic investor tends to invest in risk-free asset such as deposit in the bank since they are not familiar yet with the stock market and anxious about the risk (risk-averse type of investor. Therefore, it is important to educate domestic investor to involve in the stock exchange. Investing in portfolio of stock is one of the best choices for risk-averse investor (such as Indonesia domestic investor since it offers lower risk for a given level of return. This paper studies the optimization of Indonesian stock portfolio. The data is the historical return of 10 stocks of LQ 45 for 5 time series (January 2004 – December 2008. It will be focus on selecting stocks into a portfolio, setting 10 of stock portfolios using mean variance method combining with the linear programming (solver. Furthermore, based on Efficient Frontier concept and Sharpe measurement, there will be one stock portfolio picked as an optimum Portfolio (Namely Portfolio G. Then, Performance of portfolio G will be evaluated by using Sharpe, Treynor and Jensen Measurement to show whether the return of Portfolio G exceeds the market return. This paper also illustrates how the stock composition of the Optimum Portfolio (G succeeds to predict the portfolio return in the future (5th January – 3rd April 2009. The result of the study observed that optimization portfolio using Mean-Variance (consistent with Markowitz theory combine with linear programming can be applied into Indonesia stock’s portfolio. All the measurements (Sharpe, Jensen, and Treynor show that the portfolio G is a superior portfolio. It is also been found that the composition (weights stocks of optimum portfolio (G can be used to

Transaction fees and optimal rebalancing in the growth-optimal portfolio

OpenAIRE

Yu Feng; Matus Medo; Liang Zhang; Yi-Cheng Zhang

2010-01-01

The growth-optimal portfolio optimization strategy pioneered by Kelly is based on constant portfolio rebalancing which makes it sensitive to transaction fees. We examine the effect of fees on an example of a risky asset with a binary return distribution and show that the fees may give rise to an optimal period of portfolio rebalancing. The optimal period is found analytically in the case of lognormal returns. This result is consequently generalized and numerically verified for broad return di...

From Process to Outcome: The Effect of Portfolio Assessment on Student Learning.

Science.gov (United States)

Tiwari, Agnes; Tang, Catherine

2003-01-01

Three findings emerged from 12 Hong Kong student nurses' descriptions of their experiences of portfolio assessment: (1) despite initial anxiety, all favored portfolio use; (2) portfolios had positive academic and affective outcomes; and (3) unexpectedly, spontaneous collaborative learning and increased motivation resulted. (Contains 35…

7 CFR 4290.740 - Portfolio diversification (“overline” limitation).

Science.gov (United States)

2010-01-01

... 7 Agriculture 15 2010-01-01 2010-01-01 false Portfolio diversification (âoverlineâ limitation). 4290.740 Section 4290.740 Agriculture Regulations of the Department of Agriculture (Continued) RURAL... Enterprise for Rbic Financing § 4290.740 Portfolio diversification (“overline” limitation). (a) Without the...

Can One Portfolio Measure the Six ACGME General Competencies?

Science.gov (United States)

Jarvis, Robert M.; O'Sullivan, Patricia S.; McClain, Tina; Clardy, James A.

2004-01-01

Objective: To determine that portfolios, useable by any program, can provide needed evidence of resident performance within the ACGME general competencies. Methods: Eighteen residents constructed portfolios with selected entries from thirteen psychiatric skills. Two raters assessed whether entries reflected resident performance within the general…

Research on regularized mean-variance portfolio selection strategy with modified Roy safety-first principle.

Science.gov (United States)

Atta Mills, Ebenezer Fiifi Emire; Yan, Dawen; Yu, Bo; Wei, Xinyuan

2016-01-01

We propose a consolidated risk measure based on variance and the safety-first principle in a mean-risk portfolio optimization framework. The safety-first principle to financial portfolio selection strategy is modified and improved. Our proposed models are subjected to norm regularization to seek near-optimal stable and sparse portfolios. We compare the cumulative wealth of our preferred proposed model to a benchmark, S&P 500 index for the same period. Our proposed portfolio strategies have better out-of-sample performance than the selected alternative portfolio rules in literature and control the downside risk of the portfolio returns.

Regional Ocean Data Assimilation

KAUST Repository

Edwards, Christopher A.

2015-01-03

This article reviews the past 15 years of developments in regional ocean data assimilation. A variety of scientific, management, and safety-related objectives motivate marine scientists to characterize many ocean environments, including coastal regions. As in weather prediction, the accurate representation of physical, chemical, and/or biological properties in the ocean is challenging. Models and observations alone provide imperfect representations of the ocean state, but together they can offer improved estimates. Variational and sequential methods are among the most widely used in regional ocean systems, and there have been exciting recent advances in ensemble and four-dimensional variational approaches. These techniques are increasingly being tested and adapted for biogeochemical applications.

Agriculture's portfolio for an uncertain future: Preparing for global warming

International Nuclear Information System (INIS)

Drabenstott, M.

1992-01-01

Farmers and foresters will adapt as the climate changes, but the attendant social costs call for policy steps now to encourage even more adaptation. The challenge to policymakers can be viewed as building a balanced portfolio of climate change assets and then managing it effectively. Put simply, investing in a diverse portfolio of agricultural assets must be viewed as prudent policy. The climate seems likely to change; how much and how soon, is not known. If the climate changes, there will be social costs to the nation, and the costs could be large. A prudent way to hedge the risk of those costs is to hold a diverse portfolio of assets and assure the flexibility to use them. Such a portfolio offers the best change for agriculture to adapt successfully to whatever climate unfolds. And even if the climate stays the same, investing in such a flexible portfolio will surely pay dividends in the stream of other changes bound to come. The present rich allocation of resources must be improved if they will be effective adapting agents in the future

RISK LOAN PORTFOLIO OPTIMIZATION MODEL BASED ON CVAR RISK MEASURE

Directory of Open Access Journals (Sweden)

Ming-Chang LEE

2015-07-01

Full Text Available In order to achieve commercial banks liquidity, safety and profitability objective requirements, loan portfolio risk analysis based optimization decisions are rational allocation of assets.  The risk analysis and asset allocation are the key technology of banking and risk management.  The aim of this paper, build a loan portfolio optimization model based on risk analysis.  Loan portfolio rate of return by using Value-at-Risk (VaR and Conditional Value-at-Risk (CVaR constraint optimization decision model reflects the bank's risk tolerance, and the potential loss of direct control of the bank.  In this paper, it analyze a general risk management model applied to portfolio problems with VaR and CVaR risk measures by using Using the Lagrangian Algorithm.  This paper solves the highly difficult problem by matrix operation method.  Therefore, the combination of this paper is easy understanding the portfolio problems with VaR and CVaR risk model is a hyperbola in mean-standard deviation space.  It is easy calculation in proposed method.

The Diversification Benefits of Including Carbon Assets in Financial Portfolios

Directory of Open Access Journals (Sweden)

Yinpeng Zhang

2017-03-01

Full Text Available Carbon allowances traded in the EU-Emission Trading Scheme (EU-ETS were initially designed as an economic motivation for efficiently curbing greenhouse as emissions, but now it mimics quite a few characteristics of financial assets, and have now been used as a candidate product in building financial portfolios. In this study, we examine the time-varying correlations between carbon allowance prices with other financial indices, during the third phase of EU-ETS. The results show that, at the beginning of this period, carbon price was still strongly corrected with other financial indices. However, this connection was weakened over time. Given the relative independence of carbon assets from other financial assets, we argue for the diversification benefits of including carbon assets in financial portfolios, and building such portfolios, respectively, with the traditional global minimum variance (GMV strategy, the mean-variance-OGARCH (MV-OGARCH strategy, and the dynamic conditional correlation (DCC strategy. It is shown that the portfolio built with the MV-OGARCH strategy far out-performs the others and that including carbon assets in financial portfolios does help reduce investment risks.

Multi-objective mean-variance-skewness model for generation portfolio allocation in electricity markets

Energy Technology Data Exchange (ETDEWEB)

Pindoriya, N.M.; Singh, S.N. [Department of Electrical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Singh, S.K. [Indian Institute of Management Lucknow, Lucknow 226013 (India)

2010-10-15

This paper proposes an approach for generation portfolio allocation based on mean-variance-skewness (MVS) model which is an extension of the classical mean-variance (MV) portfolio theory, to deal with assets whose return distribution is non-normal. The MVS model allocates portfolios optimally by considering the maximization of both the expected return and skewness of portfolio return while simultaneously minimizing the risk. Since, it is competing and conflicting non-smooth multi-objective optimization problem, this paper employed a multi-objective particle swarm optimization (MOPSO) based meta-heuristic technique to provide Pareto-optimal solution in a single simulation run. Using a case study of the PJM electricity market, the performance of the MVS portfolio theory based method and the classical MV method is compared. It has been found that the MVS portfolio theory based method can provide significantly better portfolios in the situation where non-normally distributed assets exist for trading. (author)

Multi-objective mean-variance-skewness model for generation portfolio allocation in electricity markets

International Nuclear Information System (INIS)

Pindoriya, N.M.; Singh, S.N.; Singh, S.K.

2010-01-01

This paper proposes an approach for generation portfolio allocation based on mean-variance-skewness (MVS) model which is an extension of the classical mean-variance (MV) portfolio theory, to deal with assets whose return distribution is non-normal. The MVS model allocates portfolios optimally by considering the maximization of both the expected return and skewness of portfolio return while simultaneously minimizing the risk. Since, it is competing and conflicting non-smooth multi-objective optimization problem, this paper employed a multi-objective particle swarm optimization (MOPSO) based meta-heuristic technique to provide Pareto-optimal solution in a single simulation run. Using a case study of the PJM electricity market, the performance of the MVS portfolio theory based method and the classical MV method is compared. It has been found that the MVS portfolio theory based method can provide significantly better portfolios in the situation where non-normally distributed assets exist for trading. (author)

Portfolio theory and cost-effectiveness analysis: a further discussion.

Science.gov (United States)

Sendi, Pedram; Al, Maiwenn J; Rutten, Frans F H

2004-01-01

Portfolio theory has been suggested as a means to improve the risk-return characteristics of investments in health-care programs through diversification when costs and effects are uncertain. This approach is based on the assumption that the investment proportions are not subject to uncertainty and that the budget can be invested in toto in health-care programs. In the present paper we develop an algorithm that accounts for the fact that investment proportions in health-care programs may be uncertain (due to the uncertainty associated with costs) and limited (due to the size of the programs). The initial budget allocation across programs may therefore be revised at the end of the investment period to cover the extra costs of some programs with the leftover budget of other programs in the portfolio. Once the total budget is equivalent to or exceeds the expected costs of the programs in the portfolio, the initial budget allocation policy does not impact the risk-return characteristics of the combined portfolio, i.e., there is no benefit from diversification anymore. The applicability of portfolio methods to improve the risk-return characteristics of investments in health care is limited to situations where the available budget is much smaller than the expected costs of the programs to be funded.

Portfolio Effects of Renewable Energies - Basics, Models, Exemplary Results

Energy Technology Data Exchange (ETDEWEB)

Wiese, Andreas; Herrmann, Matthias

2007-07-01

The combination of sites and technologies to so-called renewable energy portfolios, which are being developed and implemented under the same financing umbrella, is currently the subject of intense discussion in the finance world. The resulting portfolio effect may allow the prediction of a higher return with the same risk or the same return with a lower risk - always in comparison with the investment in a single project. Models are currently being developed to analyse this subject and derive the portfolio effect. In particular, the effect of the spatial distribution, as well as the effects of using different technologies, suppliers and cost assumptions with different level of uncertainties, are of importance. Wind parks, photovoltaic, biomass, biogas and hydropower are being considered. The status of the model development and first results are being presented in the current paper. In a first example, the portfolio effect has been calculated and analysed using selected parameters for a wind energy portfolio of 39 sites distributed over Europe. Consequently it has been shown that the predicted yield, with the predetermined probabilities between 75 to 90%, is 3 - 8% higher than the sum of the yields for the individual wind parks using the same probabilities. (auth)

The cost of geothermal energy in the western US region:a portfolio-based approach a mean-variance portfolio optimization of the regions' generating mix to 2013.

Energy Technology Data Exchange (ETDEWEB)

Beurskens, Luuk (ECN-Energy Research Centre of the Netherland); Jansen, Jaap C. (ECN-Energy Research Centre of the Netherlands); Awerbuch, Shimon Ph.D. (.University of Sussex, Brighton, UK); Drennen, Thomas E.

2005-09-01

Energy planning represents an investment-decision problem. Investors commonly evaluate such problems using portfolio theory to manage risk and maximize portfolio performance under a variety of unpredictable economic outcomes. Energy planners need to similarly abandon their reliance on traditional, ''least-cost'' stand-alone technology cost estimates and instead evaluate conventional and renewable energy sources on the basis of their portfolio cost--their cost contribution relative to their risk contribution to a mix of generating assets. This report describes essential portfolio-theory ideas and discusses their application in the Western US region. The memo illustrates how electricity-generating mixes can benefit from additional shares of geothermal and other renewables. Compared to fossil-dominated mixes, efficient portfolios reduce generating cost while including greater renewables shares in the mix. This enhances energy security. Though counter-intuitive, the idea that adding more costly geothermal can actually reduce portfolio-generating cost is consistent with basic finance theory. An important implication is that in dynamic and uncertain environments, the relative value of generating technologies must be determined not by evaluating alternative resources, but by evaluating alternative resource portfolios. The optimal results for the Western US Region indicate that compared to the EIA target mixes, there exist generating mixes with larger geothermal shares at equal-or-lower expected cost and risk.

A new enhanced index tracking model in portfolio optimization with sum weighted approach

Science.gov (United States)

Siew, Lam Weng; Jaaman, Saiful Hafizah; Hoe, Lam Weng

2017-04-01

Index tracking is a portfolio management which aims to construct the optimal portfolio to achieve similar return with the benchmark index return at minimum tracking error without purchasing all the stocks that make up the index. Enhanced index tracking is an improved portfolio management which aims to generate higher portfolio return than the benchmark index return besides minimizing the tracking error. The objective of this paper is to propose a new enhanced index tracking model with sum weighted approach to improve the existing index tracking model for tracking the benchmark Technology Index in Malaysia. The optimal portfolio composition and performance of both models are determined and compared in terms of portfolio mean return, tracking error and information ratio. The results of this study show that the optimal portfolio of the proposed model is able to generate higher mean return than the benchmark index at minimum tracking error. Besides that, the proposed model is able to outperform the existing model in tracking the benchmark index. The significance of this study is to propose a new enhanced index tracking model with sum weighted apporach which contributes 67% improvement on the portfolio mean return as compared to the existing model.

How Course Portfolios Can Advance the Scholarship and Practice of Management Teaching

Science.gov (United States)

New, J. Randolph; Clawson, James G.; Coughlan, Richard S.; Hoyle, Joe Ben

2008-01-01

The authors believe the development, peer review, and sharing of course portfolios can significantly improve the scholarship and teaching of management. To make this case, they provide background information about course portfolios, including origins, defining features, purposes, and potential benefits. They then identify actual portfolio projects…

Systemic risk contributions: a credit portfolio approach

OpenAIRE

Düllmann, Klaus; Puzanova, Natalia

2011-01-01

We put forward a Merton-type multi-factor portfolio model for assessing banks' contributions to systemic risk. This model accounts for the major drivers of banks' systemic relevance: size, default risk and correlation of banks' assets as a proxy for interconnectedness. We measure systemic risk in terms of the portfolio expected shortfall (ES). Banks' (marginal) risk contributions are calculated based on partial derivatives of the ES in order to ensure a full risk allocation among institutions...

Enhanced index tracking modelling in portfolio optimization

Science.gov (United States)

Lam, W. S.; Hj. Jaaman, Saiful Hafizah; Ismail, Hamizun bin

2013-09-01

Enhanced index tracking is a popular form of passive fund management in stock market. It is a dual-objective optimization problem, a trade-off between maximizing the mean return and minimizing the risk. Enhanced index tracking aims to generate excess return over the return achieved by the index without purchasing all of the stocks that make up the index by establishing an optimal portfolio. The objective of this study is to determine the optimal portfolio composition and performance by using weighted model in enhanced index tracking. Weighted model focuses on the trade-off between the excess return and the risk. The results of this study show that the optimal portfolio for the weighted model is able to outperform the Malaysia market index which is Kuala Lumpur Composite Index because of higher mean return and lower risk without purchasing all the stocks in the market index.

Estimating Risk of Natural Gas Portfolios by Using GARCH-EVT-Copula Model.

Science.gov (United States)

Tang, Jiechen; Zhou, Chao; Yuan, Xinyu; Sriboonchitta, Songsak

2015-01-01

This paper concentrates on estimating the risk of Title Transfer Facility (TTF) Hub natural gas portfolios by using the GARCH-EVT-copula model. We first use the univariate ARMA-GARCH model to model each natural gas return series. Second, the extreme value distribution (EVT) is fitted to the tails of the residuals to model marginal residual distributions. Third, multivariate Gaussian copula and Student t-copula are employed to describe the natural gas portfolio risk dependence structure. Finally, we simulate N portfolios and estimate value at risk (VaR) and conditional value at risk (CVaR). Our empirical results show that, for an equally weighted portfolio of five natural gases, the VaR and CVaR values obtained from the Student t-copula are larger than those obtained from the Gaussian copula. Moreover, when minimizing the portfolio risk, the optimal natural gas portfolio weights are found to be similar across the multivariate Gaussian copula and Student t-copula and different confidence levels.

Estimating Risk of Natural Gas Portfolios by Using GARCH-EVT-Copula Model

Directory of Open Access Journals (Sweden)

Jiechen Tang

2015-01-01

Full Text Available This paper concentrates on estimating the risk of Title Transfer Facility (TTF Hub natural gas portfolios by using the GARCH-EVT-copula model. We first use the univariate ARMA-GARCH model to model each natural gas return series. Second, the extreme value distribution (EVT is fitted to the tails of the residuals to model marginal residual distributions. Third, multivariate Gaussian copula and Student t-copula are employed to describe the natural gas portfolio risk dependence structure. Finally, we simulate N portfolios and estimate value at risk (VaR and conditional value at risk (CVaR. Our empirical results show that, for an equally weighted portfolio of five natural gases, the VaR and CVaR values obtained from the Student t-copula are larger than those obtained from the Gaussian copula. Moreover, when minimizing the portfolio risk, the optimal natural gas portfolio weights are found to be similar across the multivariate Gaussian copula and Student t-copula and different confidence levels.

Valuation of large variable annuity portfolios: Monte Carlo simulation and synthetic datasets

Directory of Open Access Journals (Sweden)

Gan Guojun

2017-12-01

Full Text Available Metamodeling techniques have recently been proposed to address the computational issues related to the valuation of large portfolios of variable annuity contracts. However, it is extremely diffcult, if not impossible, for researchers to obtain real datasets frominsurance companies in order to test their metamodeling techniques on such real datasets and publish the results in academic journals. To facilitate the development and dissemination of research related to the effcient valuation of large variable annuity portfolios, this paper creates a large synthetic portfolio of variable annuity contracts based on the properties of real portfolios of variable annuities and implements a simple Monte Carlo simulation engine for valuing the synthetic portfolio. In addition, this paper presents fair market values and Greeks for the synthetic portfolio of variable annuity contracts that are important quantities for managing the financial risks associated with variable annuities. The resulting datasets can be used by researchers to test and compare the performance of various metamodeling techniques.

Shedding New Light on Project Portfolio Risk Management

Directory of Open Access Journals (Sweden)

Mariusz Hofman

2017-10-01

Full Text Available This paper constitutes an innovative attempt to analyse the risks and negative phenomena dependencies within a project portfolio. Based on the available literature, the risks and negative phenomena (that is, the problems with the availability of resources, interpersonal conflicts, irregularities in the portfolio balance, etc. specific to a project portfolio were identified. Theoretical constructs were then used to connect the identified risks with the negative phenomena. Structural equations were used to confirm the existence and quality of these constructs, as well as models describing connections between phenomena. The determination of the structural equations also provided a setting in which statistical methods (χ2, RMSEA and CFI could be used to investigate the level of fit of the constructs and models to the empirical data.

13 CFR 107.740 - Portfolio diversification (“overline” limitation).

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Portfolio diversification (âoverlineâ limitation). 107.740 Section 107.740 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION... Eligibility of A Small Business for Sbic Financing § 107.740 Portfolio diversification (“overline” limitation...

13 CFR 108.740 - Portfolio diversification (“overline” limitation).

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Portfolio diversification (âoverlineâ limitation). 108.740 Section 108.740 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION... Determining the Eligibility of A Small Business for Nmvc Financing § 108.740 Portfolio diversification...

The Role of e-Portfolios in Supporting Productive Learning

Science.gov (United States)

Yang, Min; Tai, Mui; Lim, Cher Ping

2016-01-01

e-Portfolios are a form of authentic assessment with formative functions that include showcasing and sharing learning artifacts, documenting reflective learning processes, connecting learning across various stages and enabling frequent feedback for improvements. This paper examines how e-portfolios take up these formative roles to support…

Portfolio of automated trading systems: complexity and learning set size issues.

Science.gov (United States)

Raudys, Sarunas

2013-03-01

In this paper, we consider using profit/loss histories of multiple automated trading systems (ATSs) as N input variables in portfolio management. By means of multivariate statistical analysis and simulation studies, we analyze the influences of sample size (L) and input dimensionality on the accuracy of determining the portfolio weights. We find that degradation in portfolio performance due to inexact estimation of N means and N(N - 1)/2 correlations is proportional to N/L; however, estimation of N variances does not worsen the result. To reduce unhelpful sample size/dimensionality effects, we perform a clustering of N time series and split them into a small number of blocks. Each block is composed of mutually correlated ATSs. It generates an expert trading agent based on a nontrainable 1/N portfolio rule. To increase the diversity of the expert agents, we use training sets of different lengths for clustering. In the output of the portfolio management system, the regularized mean-variance framework-based fusion agent is developed in each walk-forward step of an out-of-sample portfolio validation experiment. Experiments with the real financial data (2003-2012) confirm the effectiveness of the suggested approach.

Strategic innovation portfolio management

Directory of Open Access Journals (Sweden)

Stanković Ljiljana

2015-01-01

Full Text Available In knowledge-based economy, strategic innovation portfolio management becomes more and more important and critical factor of enterprise's success. Value creation for all the participants in value chain is more successful if it is based on efficient resource allocation and improvement of innovation performances. Numerous researches have shown that companies with best position on the market found their competitiveness on efficient development and exploitation of innovations. In decision making process, enterprise's management is constantly faced with challenge to allocate resources and capabilities as efficiently as possible, in both short and long term. In this paper authors present preliminary results of realized empirical research related to strategic innovation portfolio management in ten chosen enterprises in Serbia. The structure of the paper includes the following parts: theoretical background, explanation of research purpose and methodology, discussion of the results and concluding remarks, including limitations and directions for further research.

On portfolio risk diversification

Science.gov (United States)

Takada, Hellinton H.; Stern, Julio M.

2017-06-01

The first portfolio risk diversification strategy was put into practice by the All Weather fund in 1996. The idea of risk diversification is related to the risk contribution of each available asset class or investment factor to the total portfolio risk. The maximum diversification or the risk parity allocation is achieved when the set of risk contributions is given by a uniform distribution. Meucci (2009) introduced the maximization of the Rényi entropy as part of a leverage constrained optimization problem to achieve such diversified risk contributions when dealing with uncorrelated investment factors. A generalization of the risk parity is the risk budgeting when there is a prior for the distribution of the risk contributions. Our contribution is the generalization of the existent optimization frameworks to be able to solve the risk budgeting problem. In addition, our framework does not possess any leverage constraint.

Portfolio analysis based on the example of Zagreb Stock Exchange

OpenAIRE

Bogdan, Sinisa; Baresa, Suzana; Ivanovic, Sasa

2010-01-01

In this paper we analyze the portfolio that was selected from the Zagreb Stock Exchange and also try to assess its risks and its future offerings that are relevant in making the decisions about investments. Through the work we will explain the importance of diversification and how the very diversification reduces risk. We will also analyze the systemic risk of individual stocks within the portfolio and the systemic risk of the given portfolio and explain its importance. Through regression ana...

Teaching empirical finance courses: A project on portfolio management

Directory of Open Access Journals (Sweden)

Bruce Morley

2016-12-01

Full Text Available The aim of this article was to assess the use of a group-based project for an empirical finance type of course. It examines the outline of the project, the methodology the students are encouraged to follow and how the course is assessed. This approach enables the students to apply many of the techniques learnt on this course and other courses such as econometrics, to determine an optimal portfolio of assets given their view on the risks in the economy. The emphasis is on risk management through portfolio diversification and the use of a simple hedge strategy. The overall aim was to introduce the students to the basics of portfolio management, as many work in this industry for their industrial placements and when they graduate. The main contribution to the literature is through the analysis of an empirically based portfolio management project. The feedback from the students suggests they felt that they had learnt useful concepts and information, in an enjoyable exercise.

Fellows' Perceptions of a Mandatory Reflective Electronic Portfolio in a Geriatric Medicine Fellowship Program

Science.gov (United States)

Ruiz, Jorge G.; Qadri, Syeda S.; Karides, Marina; Castillo, Carmen; Milanez, Marcos; Roos, Bernard A.

2009-01-01

Electronic portfolios (ePortfolios) can be useful for evaluating and documenting mastery of competencies. We investigated geriatric medicine fellows' perceptions of an ePortfolio. We conducted surveys and focus groups followed by quantitative and qualitative data analysis. Our study revealed that fellows considered the ePortfolio acceptable and…

ANALYSIS OF PROJECT PORTFOLIO MANAGEMENT MATURITY: THE CASE OF A SMALL FINANCIAL INSTITUTION

Directory of Open Access Journals (Sweden)

Karoline Doro Alves Carneiro

2012-04-01

Full Text Available This study explores the implementation of project portfolio management in the organizational context. The objective is to analyze the methodology of project portfolio management adopted by an organization based in the project portfolio management maturity model proposed by Rad and Levin (2006. We developed an exploratory case study in a small financial institution that experienced problems with the implementation of its methodology in project portfolio management. As a result of study, we found that the organization has maturity level 2 in portfolio project management, and that some methodology aspects are not appropriate at this level.

The regional electricity generation mix in Scotland. A portfolio selection approach incorporating marine technologies

Energy Technology Data Exchange (ETDEWEB)

Allan, Grant; Eromenko, Igor; McGregor, Peter [Fraser of Allander Institute, Department of Economics, University of Strathclyde, Sir William Duncan Building, 130 Rottenrow, Glasgow G4 0GE (United Kingdom); Swales, Kim [Department of Economics, University of Strathclyde, Sir William Duncan Building, 130 Rottenrow, Glasgow G4 0GE (United Kingdom)

2011-01-15

Standalone levelised cost assessments of electricity supply options miss an important contribution that renewable and non-fossil fuel technologies can make to the electricity portfolio: that of reducing the variability of electricity costs, and their potentially damaging impact upon economic activity. Portfolio theory applications to the electricity generation mix have shown that renewable technologies, their costs being largely uncorrelated with non-renewable technologies, can offer such benefits. We look at the existing Scottish generation mix and examine drivers of changes out to 2020. We assess recent scenarios for the Scottish generation mix in 2020 against mean-variance efficient portfolios of electricity-generating technologies. Each of the scenarios studied implies a portfolio cost of electricity that is between 22% and 38% higher than the portfolio cost of electricity in 2007. These scenarios prove to be mean-variance 'inefficient' in the sense that, for example, lower variance portfolios can be obtained without increasing portfolio costs, typically by expanding the share of renewables. As part of extensive sensitivity analysis, we find that Wave and Tidal technologies can contribute to lower risk electricity portfolios, while not increasing portfolio cost. (author)

Large and small baseload power plants: Drivers to define the optimal portfolios

International Nuclear Information System (INIS)

Locatelli, Giorgio; Mancini, Mauro

2011-01-01

Despite the growing interest in Small Medium sized Power Plants (SMPP) international literature provides only studies related to portfolios of large plants in infinite markets/grids with no particular attention given to base load SMPP. This paper aims to fill this gap, investigating the attractiveness of SMPP portfolios respect to large power plant portfolios. The analysis includes nuclear, coal and combined cycle gas turbines (CCGT) of different plant sizes. The Mean Variance Portfolio theory (MVP) is used to define the best portfolio according to Internal Rate of Return (IRR) and Levelised Unit Electricity Cost (LUEC) considering the life cycle costs of each power plant, Carbon Tax, Electricity Price and grid dimension. The results show how large plants are the best option for large grids, while SMPP are as competitive as large plants in small grids. In fact, in order to achieve the highest profitability with the lowest risk it is necessary to build several types of different plants and, in case of small grids, this is possible only with SMPP. A further result is the application of the framework to European OECD countries and the United States assessing their portfolios. - Highlights: ► The literature about power plant portfolios does not consider small grids and IRR. ► We evaluated Base load portfolios respect to IRR and LUEC. ► We assessed the influence of grid and plant size, CO 2 cost and Electricity Price. ► Large plants are optimal for large markets even if small plants have similar IRR. ► Small plants are suitable to diversify portfolios in small grids reducing the risk.

Big Data Challenges of High-Dimensional Continuous-Time Mean-Variance Portfolio Selection and a Remedy.

Science.gov (United States)

Chiu, Mei Choi; Pun, Chi Seng; Wong, Hoi Ying

2017-08-01

Investors interested in the global financial market must analyze financial securities internationally. Making an optimal global investment decision involves processing a huge amount of data for a high-dimensional portfolio. This article investigates the big data challenges of two mean-variance optimal portfolios: continuous-time precommitment and constant-rebalancing strategies. We show that both optimized portfolios implemented with the traditional sample estimates converge to the worst performing portfolio when the portfolio size becomes large. The crux of the problem is the estimation error accumulated from the huge dimension of stock data. We then propose a linear programming optimal (LPO) portfolio framework, which applies a constrained ℓ 1 minimization to the theoretical optimal control to mitigate the risk associated with the dimensionality issue. The resulting portfolio becomes a sparse portfolio that selects stocks with a data-driven procedure and hence offers a stable mean-variance portfolio in practice. When the number of observations becomes large, the LPO portfolio converges to the oracle optimal portfolio, which is free of estimation error, even though the number of stocks grows faster than the number of observations. Our numerical and empirical studies demonstrate the superiority of the proposed approach. © 2017 Society for Risk Analysis.

Student Portfolios as Windows into Intercultural Knowledge and Knowing

Science.gov (United States)

Johnson, Esko; Hynynen, Nina

2018-01-01

This research paper deals with intercultural knowledge and knowing as displayed in higher education student portfolios. The portfolios were written by student pairs taking a global education course at Centria University of Applied Sciences, Finland, during seven academic years. Conceptual metaphor theory and metaphor analysis were utilised to…

Forecasting Value-at-Risk Under Temporal and Portfolio Aggregation

NARCIS (Netherlands)

H.J.W.G. Kole (Erik); T.D. Markwat (Thijs); A. Opschoor (Anne); D.J.C. van Dijk (Dick)

2016-01-01

textabstractWe examine the impact of temporal and portfolio aggregation on the quality of Value-at-Risk (VaR) forecasts over a horizon of ten trading days for a well-diversified portfolio of stocks, bonds and alternative investments. The VaR forecasts are constructed based on daily, weekly or

Feedback using an ePortfolio for medicine long cases: quality not quantity.

Science.gov (United States)

Bleasel, Jane; Burgess, Annette; Weeks, Ruth; Haq, Inam

2016-10-21

The evidence for the positive impact of an electronic Portfolio (ePortfolio) on feedback in medicine is mixed. An ePortfolio for medical long cases in a Graduate Medical Program was developed. The purpose of this study was to explore the perceptions of medical students and faculty of the impact of the ePortfolio on the feedback process. In total, 130 Year 3 medical students, and six faculty participated in the study. This is a mixed methods study, using a combination of both quantitative and qualitative approaches. Quantitative methods were used to quantify the number of long cases performed. Qualitative methods were used to explore the relationship between quantity and quality of feedback, and provide a rich understanding of both students' and faculty's experience and perceptions of the ePortfolio. Students received a variable quantity of feedback at each of the three studied clinical schools, with an average of between 4 - 5.4 feedback episodes per student. Feedback that was constructive, specific and timely and delivered by a senior academic was important. Quantity was not an essential factor, with two episodes of detailed feedback reported to be adequate. The barriers to the use of the ePortfolio were technical aspects of the platform that interfered with student engagement. Feedback using the ePortfolio for medical long cases is a valuable tool providing a senior clinician delivers detailed, constructive and personalized feedback in a timely fashion. The ePortfolio system needs to be user-friendly to engage students.

Der Einsatz von E-Portfolios in der Berufsausbildung - Konzeption und Potenziale

Directory of Open Access Journals (Sweden)

Uwe Elsholz

2010-02-01

Full Text Available In der beruflichen Bildung sind (E-Portfolios zur Reflexion des Gelernten – anders als etwa an Hochschulen oder in allgemeinbildenden Schulen – in Theorie und Praxis gegenwärtig kaum existent. Konzepte und Studien zum Einsatz von E-Portfolios in der Berufsausbildung und der Weiterbildung fehlen weitgehend, so dass die Potenziale von Portfolioarbeit für eine selbstbewusstere und selbstbestimmtere Gestaltung beruflichen Lernens bisher ungenutzt bleiben. Hier setzt dieser Beitrag an. Es wird ein Konzept vorgestellt, wie der Einsatz eines E-Portfolios die Berufsausbildung im dualen System unterstützen kann. Anhand des dargestellten Beispiels werden Möglichkeiten und Grenzen des Einsatzes von E-Portfolios in der beruflichen Bildung aufgezeigt. Die Umsetzung des E-Portfolios findet im Rahmen des berufswissenschaftlich begründeten E- Learning-Konzepts der Kompetenzwerkst@tt statt (vgl. Howe/Knutzen 2007. Die Kompetenzwerkst@tt ist ein softwaregestütztes Ausbildungskonzept, das sich an realen beruflichen Arbeitsprozessen und Ansätzen des Situierten Lernens orientiert. Im Mittelpunkt des E-Portfolios als Teil der Kompetenzwerkst@tt steht die lernortübergreifende Dokumentation und Reflexion der Ausbildungsinhalte der Dualen Berufsausbildung. Im Beitrag wird gezeigt, wie die konzeptionellen Überlegungen zur Portfolioarbeit in der beruflichen Bildung vom Portfolio-Diskurs in anderen Bildungsbereichen beeinflusst sind, sich aber in der Umsetzung und in den konkreten Zielsetzungen deutlich unterscheiden. Es werden darüber hinaus weitere Möglichkeiten und Optionen von Portfolioarbeit in der beruflichen Bildung aufgezeigt.

Characteristics of Omega-Optimized Portfolios at Different Levels of Threshold Returns

Directory of Open Access Journals (Sweden)

Renaldas Vilkancas

2014-12-01

Full Text Available There is little literature considering effects that the loss-gain threshold used for dividing good and bad outcomes by all downside (upside risk measures has on portfolio optimization and performance. The purpose of this study is to assess the performance of portfolios optimized with respect to the Omega function developed by Keating and Shadwick at different levels of the threshold returns. The most common choices of the threshold values used in various Omega studies cover the risk-free rate and the average market return or simply a zero return, even though the inventors of this measure for risk warn that “using the values of the Omega function at particular points can be critically misleading” and that “only the entire Omega function contains information on distribution”. The obtained results demonstrate the importance of the selected values of the threshold return on portfolio performance – higher levels of the threshold lead to an increase in portfolio returns, albeit at the expense of a higher risk. In fact, within a certain threshold interval, Omega-optimized portfolios achieved the highest net return, compared with all other strategies for portfolio optimization using three different test datasets. However, beyond a certain limit, high threshold values will actually start hurting portfolio performance while meta-heuristic optimizers typically are able to produce a solution at any level of the threshold, and the obtained results would most likely be financially meaningless.

Portfolio, refleksion og feedback

DEFF Research Database (Denmark)

Hansen, Jens Jørgen; Qvortrup, Ane; Christensen, Inger-Marie F.

2017-01-01

Denne leder definerer indledningsvist begrebet portfolio og gør rede for anvendelsesmuligheder i en uddannelseskontekst. Dernæst behandles portfoliometodens kvalitet og effekt for læring og undervisning og de centrale begreber refleksion, progression og feedback præsenteres og diskuteres. Herefter...

Methyl bromide: ocean sources, ocean sinks, and climate sensitivity.

Science.gov (United States)

Anbar, A D; Yung, Y L; Chavez, F P

1996-03-01

The oceans play an important role in the geochemical cycle of methyl bromide (CH3Br), the major carrier of O3-destroying bromine to the stratosphere. The quantity of CH3Br produced annually in seawater is comparable to the amount entering the atmosphere each year from natural and anthropogenic sources. The production mechanism is unknown but may be biological. Most of this CH3Br is consumed in situ by hydrolysis or reaction with chloride. The size of the fraction which escapes to the atmosphere is poorly constrained; measurements in seawater and the atmosphere have been used to justify both a large oceanic CH3Br flux to the atmosphere and a small net ocean sink. Since the consumption reactions are extremely temperature-sensitive, small temperature variations have large effects on the CH3Br concentration in seawater, and therefore on the exchange between the atmosphere and the ocean. The net CH3Br flux is also sensitive to variations in the rate of CH3Br production. We have quantified these effects using a simple steady state mass balance model. When CH3Br production rates are linearly scaled with seawater chlorophyll content, this model reproduces the latitudinal variations in marine CH3Br concentrations observed in the east Pacific Ocean by Singh et al. [1983] and by Lobert et al. [1995]. The apparent correlation of CH3Br production with primary production explains the discrepancies between the two observational studies, strengthening recent suggestions that the open ocean is a small net sink for atmospheric CH3Br, rather than a large net source. The Southern Ocean is implicated as a possible large net source of CH3Br to the atmosphere. Since our model indicates that both the direction and magnitude of CH3Br exchange between the atmosphere and ocean are extremely sensitive to temperature and marine productivity, and since the rate of CH3Br production in the oceans is comparable to the rate at which this compound is introduced to the atmosphere, even small

Managing sovereign credit risk in bond portfolios

OpenAIRE

Bruder, Benjamin; Hereil, Pierre; Roncalli, Thierry

2011-01-01

With the recent development of the European debt crisis, traditional index bond management has been severely called into question. We focus here on the risk issues raised by the classical market-capitalization weighting scheme. We propose an approach to properly measure sovereign credit risk in a fixed-income portfolio. For that, we assume that CDS spreads follow a SABR process and we derive a sovereign credit risk measure based on CDS spreads and duration of portfolio bonds. We then consider...

Mean-Variance Efficiency of the Market Portfolio

OpenAIRE

Rafael Falcão Noda; Roy Martelanc; José Roberto Securato

2014-01-01

The objective of this study is to answer the criticism to the CAPM based on findings that the market portfolio is far from the efficient frontier. We run a numeric optimization model, based on Brazilian stock market data from 2003 to 2012. For each asset, we obtain adjusted returns and standard deviations such that (i) the efficient frontier intersects with the market portfolio and (ii) the distance between the adjusted parameters and the sample parameters is minimized. We conclude that the a...

Testing for structural changes in large portfolios

OpenAIRE

Posch, Peter N.; Ullmann, Daniel; Wied, Dominik

2015-01-01

Model free tests for constant parameters often fail to detect structural changes in high dimensions. In practice, this corresponds to a portfolio with many assets and a reasonable long time series. We reduce the dimensionality of the problem by looking a compressed panel of time series obtained by cluster analysis and the principal components of the data. Using our methodology we are able to extend a test for a constant correlation matrix from a sub portfolio to whole indices a...

The Ocean Tracking Network and its contribution to ocean biological observation

Science.gov (United States)

Whoriskey, F. G.

2016-02-01

Animals move to meet their needs for food, shelter, reproduction and to avoid unfavorable environments. In aquatic systems, it is essential that we understand these movements if we are to sustainably manage populations and maintain healthy ecosystems. Thus the ability to document and monitor changes in aquatic animal movements is a biological observing system need. The Ocean Tracking Network (OTN) is a global research, technology development, and data management platform headquartered at Dalhousie University, in Halifax, Nova Scotia working to fill this need. OTN uses electronic telemetry to document the local-to-global movements and survival of aquatic animals, and to correlate them to oceanographic or limnological variables that are influencing movements. Such knowledge can assist with planning for and managing of anthropogenic impacts on present and future animal distributions, including those due to climate change. OTN works with various tracking methods including satellite and data storage tag systems, but its dominant focus is acoustic telemetry. OTN is built on global partnerships for the sharing of equipment and data, and has stimulated technological development in telemetry by bringing researchers with needs for new capabilities together with manufacturers to generate, test, and operationalize new technologies. This has included pioneering work into the use of marine autonomous vehicles (Slocum electric gliders; Liquid Robotics Wave Glider) in animal telemetry research. Similarly, OTN scientists worked with the Sea Mammal Research Unit to develop mobile acoustic receiver that have been placed on grey seals and linked via Bluetooth to a satellite transmitter/receiver. This provided receiver coverage in areas occupied by the seals during their typically extensive migrations and allowed for the examination of ecosystem linkages by documenting behavioral interactions the seals had with the physical environment, conspecifics, and other tagged species.

Biological response to millennial variability of dust and nutrient supply in the Subantarctic South Atlantic Ocean.

Science.gov (United States)

Anderson, Robert F; Barker, Stephen; Fleisher, Martin; Gersonde, Rainer; Goldstein, Steven L; Kuhn, Gerhard; Mortyn, P Graham; Pahnke, Katharina; Sachs, Julian P

2014-07-13

Fluxes of lithogenic material and fluxes of three palaeo-productivity proxies (organic carbon, biogenic opal and alkenones) over the past 100,000 years were determined using the (230)Th-normalization method in three sediment cores from the Subantarctic South Atlantic Ocean. Features in the lithogenic flux record of each core correspond to similar features in the record of dust deposition in the EPICA Dome C ice core. Biogenic fluxes correlate with lithogenic fluxes in each sediment core. Our preferred interpretation is that South American dust, most probably from Patagonia, constitutes a major source of lithogenic material in Subantarctic South Atlantic sediments, and that past biological productivity in this region responded to variability in the supply of dust, probably due to biologically available iron carried by the dust. Greater nutrient supply as well as greater nutrient utilization (stimulated by dust) contributed to Subantarctic productivity during cold periods, in contrast to the region south of the Antarctic Polar Front (APF), where reduced nutrient supply during cold periods was the principal factor limiting productivity. The anti-phased patterns of productivity on opposite sides of the APF point to shifts in the physical supply of nutrients and to dust as cofactors regulating productivity in the Southern Ocean. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

E-portfolios in university and blended learning settings

DEFF Research Database (Denmark)

Ørngreen, Rikke

2009-01-01

or case work, if the process of and interaction between the students are prioritised. The paper adds to the existing findings within ePortfolio and their application to formal learning settings. It discusses both the planning of and running the process, psychological barriers, students' motivation as well...... as more technological practical aspects of ePortfolio use, that are relevant for people engaged in IT and learning....

Continuous-Time Mean-Variance Portfolio Selection with Random Horizon

International Nuclear Information System (INIS)

Yu, Zhiyong

2013-01-01

This paper examines the continuous-time mean-variance optimal portfolio selection problem with random market parameters and random time horizon. Treating this problem as a linearly constrained stochastic linear-quadratic optimal control problem, I explicitly derive the efficient portfolios and efficient frontier in closed forms based on the solutions of two backward stochastic differential equations. Some related issues such as a minimum variance portfolio and a mutual fund theorem are also addressed. All the results are markedly different from those in the problem with deterministic exit time. A key part of my analysis involves proving the global solvability of a stochastic Riccati equation, which is interesting in its own right

Continuous-Time Mean-Variance Portfolio Selection with Random Horizon

Energy Technology Data Exchange (ETDEWEB)

Yu, Zhiyong, E-mail: yuzhiyong@sdu.edu.cn [Shandong University, School of Mathematics (China)

2013-12-15

This paper examines the continuous-time mean-variance optimal portfolio selection problem with random market parameters and random time horizon. Treating this problem as a linearly constrained stochastic linear-quadratic optimal control problem, I explicitly derive the efficient portfolios and efficient frontier in closed forms based on the solutions of two backward stochastic differential equations. Some related issues such as a minimum variance portfolio and a mutual fund theorem are also addressed. All the results are markedly different from those in the problem with deterministic exit time. A key part of my analysis involves proving the global solvability of a stochastic Riccati equation, which is interesting in its own right.

Ambiguity aversion and household portfolio choice puzzles: Empirical evidence*

Science.gov (United States)

Dimmock, Stephen G.; Kouwenberg, Roy; Mitchell, Olivia S.; Peijnenburg, Kim

2017-01-01

We test the relation between ambiguity aversion and five household portfolio choice puzzles: nonparticipation in equities, low allocations to equity, home-bias, own-company stock ownership, and portfolio under-diversification. In a representative US household survey, we measure ambiguity preferences using custom-designed questions based on Ellsberg urns. As theory predicts, ambiguity aversion is negatively associated with stock market participation, the fraction of financial assets in stocks, and foreign stock ownership, but it is positively related to own-company stock ownership. Conditional on stock ownership, ambiguity aversion is related to portfolio under-diversification, and during the financial crisis, ambiguity-averse respondents were more likely to sell stocks. PMID:28458446

Ambiguity aversion and household portfolio choice puzzles: Empirical evidence.

Science.gov (United States)

Dimmock, Stephen G; Kouwenberg, Roy; Mitchell, Olivia S; Peijnenburg, Kim

2016-03-01

We test the relation between ambiguity aversion and five household portfolio choice puzzles: nonparticipation in equities, low allocations to equity, home-bias, own-company stock ownership, and portfolio under-diversification. In a representative US household survey, we measure ambiguity preferences using custom-designed questions based on Ellsberg urns. As theory predicts, ambiguity aversion is negatively associated with stock market participation, the fraction of financial assets in stocks, and foreign stock ownership, but it is positively related to own-company stock ownership. Conditional on stock ownership, ambiguity aversion is related to portfolio under-diversification, and during the financial crisis, ambiguity-averse respondents were more likely to sell stocks.

Equity portfolio optimization: A DEA based methodology applied to the Zagreb Stock Exchange