Pipeline Architecture and Parallel Computation-Based Real-Time Stereovision Tracking System for Surgical Navigation

This paper studies the development of a real-time stereovision system to track multiple infrared markers attached to a surgical instrument. Multiple stages of pipeline in field-programmable gate array (FPGA) are developed to recognize the targets in both left and right image planes and to give each target a unique label. The pipeline architecture includes a smoothing filter, an adaptive threshold module, a connected component labeling operation, and a centroid extraction process. A parallel distortion correction method is proposed and implemented in a dual-core DSP. A suitable kinematic model is established for the moving targets, and a novel set of parallel and interactive computation mechanisms is proposed to position and track the targets, which are carried out by a cross-computation method in a dual-core DSP. The proposed tracking system can track the 3-D coordinate, velocity, and acceleration of four infrared markers with a delay of 9.18 ms. Furthermore, it is capable of tracking a maximum of 110 infrared markers without frame dropping at a frame rate of 60 f/s. The accuracy of the proposed system can reach the scale of 0.37 mm RMS along the x- and y-directions and 0.45 mm RMS along the depth direction (the depth is from 0.8 to 0.45 m). The performance of the proposed system can meet the requirements of applications such as surgical navigation, which needs high real time and accuracy capability.

Developing Porphyra/salmon integrated aquaculture for bioremediation and diversification of the aquaculture industry

FUNCTIONAL-FORM GROUPS; RED ALGAE; ATLANTIC SALMON; NEW-HAMPSHIRE; NITROGEN; PHOSPHORUS; RHODOPHYTA; TEMPERATURE; NUTRIENTS; KJELLMAN

The relationship between rural livelihoods and livestock keeping: the case of Sidama Zone, Southern Ethiopia

This study examines the relationship between rural livelihoods and livestock keeping in Sidama Zones, southern Ethiopia. The livelihood context, assets and strategies of households are the key features of rural livelihoods considered in the study; while households’ livestock ownership, dependence on livestock and livestock management are the main aspects of livestock keeping examined. The study used the sustainable livelihood approach as a framework for data collection and analysis. Describing the main features of rural livelihoods and livestock keeping, and the general pattern of relationship between them, this study mainly aims at identifying the main livelihood factors that determine livestock keeping in the study area. Descriptive statistics, pair wise correlations, mean comparisons and analysis of variance were used to describe rural livelihoods and livestock keeping as well as the relationship between them. Tobit regressions were used to examine the effect of the various livelihood factors on households’ livestock ownership and dependence; Poisson regressions are used to investigate the factors that influence the intensity of livestock management measured by the use of different technologies and inputs. The findings indicated that a number of livelihood factors - assets, livelihood strategies, livelihood shocks and institutional supports - significantly determine the different aspects of livestock keeping. These include: human assets such as age, education and family size; social assets such as membership to social groups; financial assets such as credit; natural assets such as land, and household physical assets; and livelihood strategies such as diversification into farm and nonfarm activities, and coping mechanisms. In addition the livelihood vulnerability context such as shocks and institutional support are among the main determinants of livestock keeping. The results, by and large, matched the findings of previous studies, and it is concluded that households livestock keeping depends on their livelihoods. Accordingly, it is recommended that policies aiming at livestock asset building and productivity improvement should take the livelihoods of rural households in to consideration. As such the study contribute to scholarly works in the area of rural livelihoods, in general, and livestock keeping, in particular. It also contributes to a better understanding of the problems of livestock keeping within the context of rural livelihoods in the country and to the formulation of appropriate policy for the development of the sector.

Empirical Evidence on Relationships between Ex Ante Innovation Pursuit and Post-M&A Performance in the Vietnamese M&A Industry, 2005-2012

This research aims to communicate new results of empirical investigations to learn about the relationship between determination of controlling an acquired firm’s capital, assets and brand versus its capability of innovation and ex post performance of the rising Vietnamese M&A industry in the 2005-2012 period. The analysis employs a categorical data sample, consisting of 212 M&A cases reported by various information sources, and performs a number of logistic regressions with significant results as follows. Firstly, the overall relationship between pre-M&A pursuit’s determination on acquiring resources and performance of the post-M&A performance is found significant. There exist profound effects of a ‘size matters’ strategy in M&A ex post performance. When there is an overwhelming ‘resources acquiring’ strategy, the innovation factor’s explanatory power becomes negligible. Secondly, for negative performance of post-M&A operations, the emphasis on both capital base and asset size, and the brand value at the time of the M&A pursuit is the major explanation in the post-M&A period. So does the absence of innovation as a goal in the pre-M&A period. These two insights together are useful in careful M&A planning. Lastly, expensive pre-M&A expenditures tend to adversely affect the post-M&A performance. As a general conclusion, this study shows that innovation can be an important factor to pursue in M&A transitions, together with the need to emphasize and find capable and willing human capital, rather than a capital base (equity or debt) and existing values of the acquired brands.

Dynamic evolution of the alpha (α) and beta (β) keratins has accompanied integument diversification and the adaptation of birds into novel lifestyles.

BACKGROUND: Vertebrate skin appendages are constructed of keratins produced by multigene families. Alpha (α) keratins are found in all vertebrates, while beta (β) keratins are found exclusively in reptiles and birds. We have studied the molecular evolution of these gene families in the genomes of 48 phylogenetically diverse birds and their expression in the scales and feathers of the chicken. RESULTS: We found that the total number of α-keratins is lower in birds than mammals and non-avian reptiles, yet two α-keratin genes (KRT42 and KRT75) have expanded in birds. The β-keratins, however, demonstrate a dynamic evolution associated with avian lifestyle. The avian specific feather β-keratins comprise a large majority of the total number of β-keratins, but independently derived lineages of aquatic and predatory birds have smaller proportions of feather β-keratin genes and larger proportions of keratinocyte β-keratin genes. Additionally, birds of prey have a larger proportion of claw β-keratins. Analysis of α- and β-keratin expression during development of chicken scales and feathers demonstrates that while α-keratins are expressed in these tissues, the number and magnitude of expressed β-keratin genes far exceeds that of α-keratins. CONCLUSIONS: These results support the view that the number of α- and β-keratin genes expressed, the proportion of the β-keratin subfamily genes expressed and the diversification of the β-keratin genes have been important for the evolution of the feather and the adaptation of birds into multiple ecological niches.

Resolving questions about bias in real and hypothetical referenda

Despite 10 years of research on behavior in hypothetical referenda, conflict remains in the literature on whether or not the mechanism generates biased responses compared to real referenda, and the nature and source of any such bias. Almost all previous inquiry in respect of this issue has concentrated on bias at the aggregate level. This paper reports a series of three experiments which focuses on bias at the individual level and how this can translate to bias at the aggregate level. The authors argue that only an individual approach to hypothetical bias is consistent with the concept of incentive compatibility. The results of these experiments reflect these previous conflicting findings but go on to show that individual hypothetical bias is a robust result driven by the differing influence of pure self-interest and other-regarding preferences in real and hypothetical situations, rather than by a single behavioral theory such as free riding. In a hypothetical situation these preferences cause yea-saying and non-demand revealing voting. This suggests that investigation of individual respondents in other hypothetical one-shot binary choices may also provide us with insights into aggregate behavior in these situations.

Down with MNE-centric theories! Market entry and expansion as the bundling of MNE and local assets

Both Anderson and Gatignon and the Uppsala internationalization model see the initial mode of foreign market entry and subsequent modes of operation as unilaterally determined by multinational enterprises (MNEs) arbitraging control and risk and increasing their commitment as they gain experience in the target market. OLI and internalization models do recognize that foreign market entry requires the bundling of MNE and complementary local assets, which they call location or country-specific advantages, but implicitly assume that those assets are freely accessible to MNEs. In contrast to both of these MNE-centric views, I explicitly consider the transactional characteristics of complementary local assets and model foreign market entry as the optimal assignment of equity between their owners and MNEs. By looking at the relative efficiency of the different markets in which MNE and complementary local assets are traded, and at how these two categories of assets match, I am able to predict whether equity will be held by MNEs or by local firms, or shared between them, and whether MNEs will enter through greenfields, brownfields, or acquisitions. The bundling model I propose has interesting implications for the evolution of the MNE footprint in host countries, and for the reasons behind the emergence of Dragon MNEs.

An FPGA based decimation filter processor design for real-time continuous-time Σ−Δ modulator performance measurement and evaluation

This paper reports on a Field Programmable Gate Array (FPGA) implementation as well as prototyping for real-time testing of a low complexity high efficiency decimation filter processor which is deployed in conjunction with a custom built low-power jitter insensitive Continuous Time (CT) Sigma-Delta (Σ-Δ) Modulator to measure and assess its performance. The CT Σ-Δ modulator/decimation filter cascade can be used in integrated all-digital microphone interfaces for a variety of applications including mobile phone handsets, wireless handsets as well as other applications requiring all-digital microphones. The work reported here concentrates on the design and implementation as well as prototyping on a Xilinx Spartan 3 FPGA development system and real-time testing of the decimation processing part deploying All-Pass based structures to process the bit stream coming from CT Σ-Δ modulator hence measuring in real-time and fully assessing the modulator's performance.

A traffic differentiation add-on to the IEEE 802.15.4 protocol: implementation and experimental validation over a real-time operating system

The IEEE 802.15.4 is the most widespread used protocol for Wireless Sensor Networks (WSNs) and it is being used as a baseline for several higher layer protocols such as ZigBee, 6LoWPAN or WirelessHART. Its MAC (Medium Access Control) supports both contention-free (CFP, based on the reservation of guaranteed time-slots GTS) and contention based (CAP, ruled by CSMA/CA) access, when operating in beacon-enabled mode. Thus, it enables the differentiation between real-time and best-effort traffic. However, some WSN applications and higher layer protocols may strongly benefit from the possibility of supporting more traffic classes. This happens, for instance, for dense WSNs used in time-sensitive industrial applications. In this context, we propose to differentiate traffic classes within the CAP, enabling lower transmission delays and higher success probability to timecritical messages, such as for event detection, GTS reservation and network management. Building upon a previously proposed methodology (TRADIF), in this paper we outline its implementation and experimental validation over a real-time operating system. Importantly, TRADIF is fully backward compatible with the IEEE 802.15.4 standard, enabling to create different traffic classes just by tuning some MAC parameters.

Search-for-yield in Portuguese fixed-income mutual funds and monetary policy

This paper studies the effects of monetary policy on mutual fund risk taking using a sample of Portuguese fixed-income mutual funds in the 2000-2012 period. Firstly I estimate time-varying measures of risk exposure (betas) for the individual funds, for the benchmark portfolio, as well as for a representative equally-weighted portfolio, through 24-month rolling regressions of a two-factor model with two systematic risk factors: interest rate risk (TERM) and default risk (DEF). Next, in the second phase, using the estimated betas, I try to understand what portion of the risk exposure is in excess of the benchmark (active risk) and how it relates to monetary policy proxies (one-month rate, Taylor residual, real rate and first principal component of a cross-section of government yields and rates). Using this methodology, I provide empirical evidence that Portuguese fixed-income mutual funds respond to accommodative monetary policy by significantly increasing exposure, in excess of their benchmarks, to default risk rate and slightly to interest risk rate as well. I also find that the increase in funds’ risk exposure to gain a boost in return (search-for-yield) is more pronounced following the 2007-2009 global financial crisis, indicating that the current historic low interest rates may incentivize excessive risk taking. My results suggest that monetary policy affects the risk appetite of non-bank financial intermediaries.

Real convergence in per capita output and growth in Eurozone: A time-series approach

The real convergence hypothesis has spurred a myriad of empirical tests and approaches in the economic literature. This Work Project intends to test for real output and growth convergence in all N(N-1)/2 possible pairs of output and output growth gaps of 14 Eurozone countries. This paper follows a time-series approach, as it tests for the presence of unit roots and persistence changes in the above mentioned pairs of output gaps, as well as for the existence of growth convergence with autoregressive models. Overall, significantly greater evidence has been found to support growth convergence rather than output convergence in our sample.

Efectos del sistema de multifondos en el Régimen de Ahorro Individual en Colombia

Recientemente, el gobierno nacional radicó un proyecto de reforma financiera en el que se propone flexibilizar la regulación de los Fondos de Pensiones. En particular, se propone que los agentes pueden escoger la composición del portafolio en el que están invertidos sus ahorros pensionales. Para evaluar los posibles efectos de este cambio sobre el bienestar de los agentes, este trabajo analiza las decisiones de inversión de un individuo con función de utilidad con aversión absoluta al riesgo constante (CARA) frente a la Teoría de la diversificación del portafolio. Adicionalmente, se realiza un ejercicio contrafactual con el fin de calcular cual hubiera sido el valor del activo pensional para diferentes individuos si la legislación propuesta por el gobierno hubiera aplicado para el período 1980-2008. Este ejercicio se realiza utilizando información de las Bolsas de Valores de Colombia y la Encuesta de Calidad de Vida 2003 (ECV 2003), siguiendo la metodología de Herscovich (2003) los resultados del análisis teórico sugieren que ante un mayor valor acumulado en las cuentas de pensión, los individuos disminuyen su exposición ante el riesgo en sus portafolios. Así, la composición del portafolio debe estar más concentrada en renta variable para los agentes jóvenes y más concentrada en renta fija para los agentes viejos. Por otro lado, el ejercicio contrafactual, indica que la mejor decisión habría sido invertir todo el portafolio en activos de renta variable. Este contraste en los resultados llama la atención acerca de dos problemas: Primero, es posible que la estrategia que maximiza la utilidad ex-ante de los individuos no sea la misma que maximiza el valor de su pensión. Segundo, el ejercicio presentado parte del supuesto de que no hay información adicional que permita suponer cambios de tendencia o de volatilidad en las rentabilidades de los distintos activos financieros. No obstante, es claro que los especialistas en el mercado financiero cuentan con información suficiente para predecir este tipo de eventos. Por esta razón, el estudio sugiere que el papel de la asesoría financiera a los ahorradores es fundamental para permitir un cambio al sistema multifondos, puesto que el incremento en las opciones de inversión no conduce a un incremento en el bienestar de los individuos en ausencia de información. Adicionalmente, al comparar la evolución de las cuentas de pensión con los porcentajes históricos y con el sistema multifondos, se encuentra un mejor desempeño cuando el porcentaje de inversión en activos de renta variable es mayor que el actual, lo cual sugiere un incremento en la restricción actual de inversión de activos de renta variable para mejorar el desempeño de los fondos.

A distributed environment for virtual and/or real experiments for underwater robots

This paper presents the distributed environment for virtual and/or real experiments for underwater robots (DEVRE). This environment is composed of a set of processes running on a local area network composed of three sites: 1) the onboard AUV computer; 2) a surface computer used as human-machine interface (HMI); and 3) a computer used for simulating the vehicle dynamics and representing the virtual world. The HMI can be transparently linked to the real sensors and actuators dealing with a real mission. It can also be linked with virtual sensors and virtual actuators, dealing with a virtual mission. The aim of DEVRE is to assist engineers during the software development and testing in the lab prior to real experiments

Stock return comovements and integration within the Latin American integrated market

Financial integration has been pursued aggressively across the globe in the last fifty years; however, there is no conclusive evidence on the diversification gains (or losses) of such efforts. These gains (or losses) are related to the degree of comovements and synchronization among increasingly integrated global markets. We quantify the degree of comovements within the integrated Latin American market (MILA). We use dynamic correlation models to quantify comovements across securities as well as a direct integration measure. Our results show an increase in comovements when we look at the country indexes, however, the increase in the trend of correlation is previous to the institutional efforts to establish an integrated market in the region. On the other hand, when we look at sector indexes and an integration measure, we find a decreased in comovements among a representative sample of securities form the integrated market.

Estado situacional de los algoritmos genéticos en los negocios internacionales

La computación evolutiva y muy especialmente los algoritmos genéticos son cada vez más empleados en las organizaciones para resolver sus problemas de gestión y toma de decisiones (Apoteker & Barthelemy, 2000). La literatura al respecto es creciente y algunos estados del arte han sido publicados. A pesar de esto, no hay un trabajo explícito que evalúe de forma sistemática el uso de los algoritmos genéticos en problemas específicos de los negocios internacionales (ejemplos de ello son la logística internacional, el comercio internacional, el mercadeo internacional, las finanzas internacionales o estrategia internacional). El propósito de este trabajo de grado es, por lo tanto, realizar un estado situacional de las aplicaciones de los algoritmos genéticos en los negocios internacionales.